NEWS revision 1.17
1 This file contains information about GCC releases which has been generated 2 automatically from the online release notes. It covers releases of GCC 3 (and the former EGCS project) since EGCS 1.0, on the line of development 4 that led to GCC 3. For information on GCC 2.8.1 and older releases of GCC 2, 5 see ONEWS. 6 7 ====================================================================== 8 http://gcc.gnu.org/gcc-12/index.html 9 10 GCC 12 Release Series 11 12 May 8, 2023 13 14 The GCC developers are pleased to announce the release of GCC 12.3. 15 16 This release is a bug-fix release, containing fixes for regressions in 17 GCC 12.2 relative to previous releases of GCC. 18 19 Release History 20 21 GCC 12.3 22 May 8, 2023 ([1]changes, [2]documentation) 23 24 GCC 12.2 25 Aug 19, 2022 ([3]changes, [4]documentation) 26 27 GCC 12.1 28 May 6, 2022 ([5]changes, [6]documentation) 29 30 References and Acknowledgements 31 32 GCC used to stand for the GNU C Compiler, but since the compiler 33 supports several other languages aside from C, it now stands for the 34 GNU Compiler Collection. 35 36 A list of [7]successful builds is updated as new information becomes 37 available. 38 39 The GCC developers would like to thank the numerous people that have 40 contributed new features, improvements, bug fixes, and other changes as 41 well as test results to GCC. This [8]amazing group of volunteers is 42 what makes GCC successful. 43 44 For additional information about GCC please refer to the [9]GCC project 45 web site or contact the [10]GCC development mailing list. 46 47 To obtain GCC please use [11]our mirror sites or [12]our version 48 control system. 49 50 51 For questions related to the use of GCC, please consult these web 52 pages and the [13]GCC manuals. If that fails, the 53 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 54 web pages and the development of GCC are welcome on our developer 55 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 56 archives. 57 58 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 59 distribution of this entire article is permitted in any medium, 60 provided this notice is preserved. 61 62 These pages are [18]maintained by the GCC team. Last modified 63 2023-05-08. 64 65 References 66 67 1. http://gcc.gnu.org/gcc-12/changes.html 68 2. http://gcc.gnu.org/onlinedocs/12.3.0/ 69 3. http://gcc.gnu.org/gcc-12/changes.html 70 4. http://gcc.gnu.org/onlinedocs/12.2.0/ 71 5. http://gcc.gnu.org/gcc-12/changes.html 72 6. http://gcc.gnu.org/onlinedocs/12.1.0/ 73 7. http://gcc.gnu.org/gcc-12/buildstat.html 74 8. http://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Contributors.html 75 9. http://gcc.gnu.org/index.html 76 10. mailto:gcc (a] gcc.gnu.org 77 11. http://gcc.gnu.org/mirrors.html 78 12. http://gcc.gnu.org/git.html 79 13. https://gcc.gnu.org/onlinedocs/ 80 14. mailto:gcc-help (a] gcc.gnu.org 81 15. mailto:gcc (a] gcc.gnu.org 82 16. https://gcc.gnu.org/lists.html 83 17. https://www.fsf.org/ 84 18. https://gcc.gnu.org/about.html 85 ====================================================================== 86 http://gcc.gnu.org/gcc-12/changes.html 87 88 GCC 12 Release Series 89 Changes, New Features, and Fixes 90 91 This page is a "brief" summary of some of the huge number of 92 improvements in GCC 12. You may also want to check out our [1]Porting 93 to GCC 12 page and the [2]full GCC documentation. 94 95 Caveats 96 97 * An ABI incompatibility between C and C++ when passing or returning 98 by value certain aggregates containing zero width bit-fields has 99 been discovered on various targets. As mentioned in [3]PR102024, 100 since the [4]PR42217 fix in GCC 4.5 the C++ front-end has been 101 removing zero width bit-fields from the internal representation of 102 the aggregates after the layout of those aggregates, but the C 103 front-end kept them, so passing e.g. struct S { float a; int : 0; 104 float b; } or struct T { float c; int : 0; } by value could differ 105 between C and C++. Starting with GCC 12 the C++ front-end no longer 106 removes those bit-fields from the internal representation and per 107 clarified psABI some targets have been changed, so that they either 108 ignore those bit-fields in the argument passing by value decisions 109 in both C and C++, or they always take them into account. x86-64, 110 ARM and AArch64 will always ignore them (so there is a C ABI 111 incompatibility between GCC 11 and earlier with GCC 12 or later), 112 PowerPC64 ELFv2 and S/390 always take them into account (so there 113 is a C++ ABI incompatibility, GCC 4.4 and earlier compatible with 114 GCC 12 or later, incompatible with GCC 4.5 through GCC 11). RISC-V 115 has changed the handling of these already starting with GCC 10. As 116 the ABI requires, MIPS takes them into account handling function 117 return values so there is a C++ ABI incompatibility with GCC 4.5 118 through 11. For function arguments on MIPS, refer to [5]the MIPS 119 specific entry. GCC 12 on the above targets will report such 120 incompatibilities as warnings or other diagnostics unless 121 -Wno-psabi is used. 122 * C: Computed gotos require a pointer type now. 123 * C++: Two non-standard std::pair constructors have been deprecated. 124 These allowed the use of an rvalue and a literal 0 to construct a 125 pair containing a move-only type and a pointer. The nullptr keyword 126 should be used to initialize the pointer member instead of a 127 literal 0, as this is portable to other C++ implementations. 128 * The configuration option --enable-libstdcxx-allocator no longer 129 supports the bitmap, mt, and pool arguments. Those configurations 130 had been broken for some time. 131 * D: Building and bootstrapping GDC, the D compiler, now requires a 132 working GDC compiler (GCC version 9.1 or later) and D runtime 133 library, libphobos, as the D front end is written in D. On some 134 targets, libphobos isn't enabled by default, but compiles and works 135 if --enable-libphobos is used. Other targets may require a more 136 recent minimum version of GCC to bootstrap. Specifics are 137 documented for affected targets in the [6]manual for installing 138 GCC. 139 * Fortran: OpenMP code using the omp_lib.h include file can no longer 140 be compiled with -std=f95 but now requires at least -std=f2003. 141 Alternatively, use the omp_lib module, which still supports 142 -std=f95 and is recommended to be used instead in general. 143 * OpenMP offloading to Intel MIC has been deprecated and will be 144 removed in a future release. 145 * The cr16 target with the cr16-*-* configuration has been obsoleted 146 and will be removed in a future release. 147 * The hppa[12]*-*-hpux10* and hppa[12]*-*-hpux11* configurations 148 targeting 32-bit PA-RISC with HP-UX have been obsoleted and will be 149 removed in a future release. 150 * The m32c*-*-rtems* configuration has been obsoleted and will be 151 removed in a future release. 152 * The support for the m32r-*-linux*, m32rle-*-linux*, 153 m68k*-*-openbsd* and vax-*-openbsd* configurations has been 154 removed. 155 * STABS: Support for emitting the STABS debugging format is 156 deprecated and will be removed in the next release. All ports now 157 default to emit DWARF (version 2 or later) debugging info or are 158 obsoleted. 159 * The optimization level -Ofast now implies 160 -fno-semantic-interposition. 161 162 General Improvements 163 164 * Vectorization is enabled at -O2 which is now equivalent to the 165 original -O2 -ftree-vectorize -fvect-cost-model=very-cheap. Note 166 that default vectorizer cost model has been changed which used to 167 behave as -fvect-cost-model=cheap were specified. 168 * GCC now supports the [7]ShadowCallStack sanitizer, which can be 169 enabled using the command-line option 170 [8]-fsanitize=shadow-call-stack. This sanitizer currently only 171 works on AArch64 targets and it requires an environment in which 172 all code has been compiled with -ffixed-r18. Its primary initial 173 user is the Linux kernel. 174 175 New Languages and Language specific improvements 176 177 * OpenMP 178 + OpenMP 5.0 support has been extended: The close map modifier 179 and the affinity clause are now supported. In addition, 180 Fortran gained the following features which were available in 181 C and C++ before: declare variant is now available, depobj, 182 mutexinoutset and iterator can now also be used with the 183 depend clause, defaultmap has been updated for OpenMP 5.0, and 184 the loop directive and combined directives involving the 185 master directive have been added. 186 + The following OpenMP 5.1 features have been added: support for 187 expressing OpenMP directives as C++ 11 attributes, the masked 188 and scope constructs, the nothing and error directives, and 189 using primary with the proc_bind clause and OMP_PROC_BIND 190 environment variable, the reproducible and unconstrained 191 modifiers to the order clause, and, for C/C++ only, the align 192 and allocator modifiers to the allocate clause and the atomic 193 extensions are now available. The OMP_PLACE environment 194 variable supports the OpenMP 5.1 features. In addition, the 195 OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT environment variables 196 and their associated API routines are now supported as well as 197 the memory-allocation routines added for Fortran and extended 198 for C/C++ in OpenMP 5.1. In Fortran code, strictly structured 199 blocks can be used. 200 + The [9]OpenMP Implementation Status can be found in the 201 libgomp manual. 202 * Version 2.6 of the [10]OpenACC specification continues to be 203 maintained and improved in the C, C++ and Fortran compilers. See 204 the [11]implementation status section on the OpenACC wiki page and 205 the [12]run-time library documentation for further information. In 206 addition to general performance tuning and bug fixing, new features 207 include: 208 + OpenACC worker parallelism for [13]AMD GPUs (already for a 209 long time supported for [14]Nvidia GPUs). 210 + Data privatization/sharing at the OpenACC gang level. 211 + Considerable improvements for the experimental OpenACC 212 'kernels' decomposition ([15]--param 213 openacc-kernels=decompose). 214 + A new warning flag [16]-Wopenacc-parallelism to warn about 215 potentially suboptimal choices related to OpenACC parallelism. 216 * The offload target code generation for OpenMP and OpenACC can now 217 be better adjusted using the new [17]-foffload-options= flag and 218 the pre-existing but now documented [18]-foffload= flag. 219 220 Ada 221 222 * Ada 2022 223 + Added the -gnat2022 flag to indicate strict Ada 2022 224 compliance. The old -gnat2020 flag is now deprecated. 225 + Support for Big Numbers (Annex G) has seen continuous 226 improvements. It is now considered complete. It is compatible 227 with SPARK, i.e. can be used from SPARK code. 228 + Continuous improvements to the Ada 2022 standard since GCC 11. 229 + Greatly improved compile time support. More functions can now 230 have the with Static aspect and can be used in more contexts. 231 * Ada 2022 extensions. The use of the -gnatX flag is necessary to 232 access these features as they are not considered stable or 233 standard. 234 + Fixed lower bound for unconstrained arrays. 235 o type Matrix is array (Natural range 0 .. <>, Natural 236 range 0 .. <>) of Integer; is now valid. 237 o Subtypes can also specify a lower bound: subtype String_1 238 is String (1 .. <>);. Boundaries from slices will "slide" 239 to the correct lower bound of the subtype. 240 + Generalized Object.Operand notation. The following code is now 241 valid V.Add_Element(42);, with V being a vector, for example. 242 + Additional when constructs. Keywords return, goto and raise 243 can now use when in addition to the existing exit when. The 244 following expression is therefore now valid raise 245 Constraint_Error with "Element is null" when Element = null; 246 + Pattern matching 247 o The case statement has been extended to cover records and 248 arrays as well as finer grained casing on scalar types. 249 In the future it is expected to provide more compile time 250 guarantees when accessing discriminated fields. Case 251 exhaustion is supported for pattern matching. An example 252 would be 253 type Sign is (Neg, Zero, Pos); 254 255 function Multiply (S1, S2 : Sign) return Sign is 256 (case (S1, S2) is 257 when (Neg, Neg) | (Pos, Pos) => Pos, 258 when (Zero, <>) | (<>, Zero) => Zero, 259 when (Neg, Pos) | (Pos, Neg) => Neg); 260 261 * gnatfind and gnatxref, which were already deprecated, have been 262 removed. 263 * Greatly expanded code covered by contracts. Thanks to this work, 264 there are now several Ada standard libraries fully proven in SPARK 265 which means they have no runtime nor logical errors. They are 266 mostly numeric and string handling libraries. 267 * Enable return-slot optimization for Pure functions. 268 * General optimizations, improvements and additions to the standard 269 library. Performance, correctness and in some cases stability was 270 improved. Memory pools have also seen some minor enhancements. 271 * Improvements to embedded-RTOS targets such as RTEMS, VxWorks and 272 QNX. Older targets were removed or cleaned. 273 * Added some [19]hardening features. 274 275 C family 276 277 * Support for __builtin_shufflevector compatible with the clang 278 language extension was added. 279 * Support for attribute unavailable was added. 280 * A new built-in function, __builtin_assoc_barrier, was added. It can 281 be used to inhibit re-association of floating-point expressions. 282 * Support for __builtin_dynamic_object_size compatible with the clang 283 language extension was added. 284 * New warnings: 285 + [20]-Wbidi-chars warns about potentially misleading UTF-8 286 bidirectional control characters. The default is 287 -Wbidi-chars=unpaired ([21]PR103026) 288 + [22]-Warray-compare warns about comparisons between two 289 operands of array type ([23]PR97573) 290 * Enhancements to existing warnings: 291 + [24]-Wattributes has been extended so that it's possible to 292 use -Wno-attributes=ns::attr or -Wno-attributes=ns:: to 293 suppress warnings about unknown scoped attributes (in C++11 294 and C2X). Similarly, #pragma GCC diagnostic ignored_attributes 295 "vendor::attr" can be used to achieve the same effect 296 ([25]PR101940) 297 298 C 299 300 * Some new features from the upcoming C2X revision of the ISO C 301 standard are supported with -std=c2x and -std=gnu2x. Some of these 302 features are also supported as extensions when compiling for older 303 language versions. In addition to the features listed, some 304 features previously supported as extensions and now added to the C 305 standard are enabled by default in C2X mode and not diagnosed with 306 -std=c2x -Wpedantic. 307 + Digit separators (as in C++) are supported for C2X. 308 + The #elifdef and #elifndef preprocessing directives are now 309 supported. 310 + The printf and scanf format checking with [26]-Wformat now 311 supports the %b format specified by C2X for binary integers, 312 and the %B format recommended by C2X for printf. 313 314 C++ 315 316 * Several C++23 features have been implemented: 317 + [27]P1938R3, if consteval ([28]PR100974) 318 + [29]P0849R8, auto(x): decay-copy in the language 319 ([30]PR103049) 320 + [31]P2242R3, Non-literal variables (and labels and gotos) in 321 constexpr functions ([32]PR102612) 322 + [33]P2334R1, Support for preprocessing directives elifdef and 323 elifndef ([34]PR102616) 324 + [35]P2360R0, Extend init-statement to allow alias-declaration 325 ([36]PR102617) 326 + [37]P2128R6, Multidimensional subscript operator 327 + [38]DR 2397, auto specifier for pointers and references to 328 arrays ([39]PR100975) 329 * Several C++ Defect Reports have been resolved, e.g.: 330 + [40]DR 960, Covariant functions and lvalue/rvalue references 331 + [41]DR 1227, Mixing immediate and non-immediate contexts in 332 deduction failure 333 + [42]DR 1315, Restrictions on non-type template arguments in 334 partial specializations 335 + [43]DR 2082, Referring to parameters in unevaluated operands 336 of default arguments 337 + [44]DR 2351, void{} 338 + [45]DR 2374, Overly permissive specification of enum 339 direct-list-initialization 340 + [46]DR 2397, auto specifier for pointers and references to 341 arrays 342 + [47]DR 2446, Questionable type-dependency of concept-ids 343 * New command-line option -fimplicit-constexpr can be used to make 344 inline functions implicitly constexpr ([48]git) 345 * New command-line option -ffold-simple-inlines can be used to fold 346 calls to certain trivial inline functions (currently std::move, 347 std::forward, std::addressof and std::as_const). In contrast to 348 inlining such calls, folding means that no intermediate code or 349 debug information will be generated for them; this minimizes the 350 abstraction penalty incurred for using these functions versus using 351 the fundamental operations from which they're defined (e.g. 352 std::move versus static_cast). This flag is enabled by default when 353 -fno-inline is not active. 354 * Deduction guides can be declared at class scope ([49]PR79501) 355 * [50]-Wuninitialized warns about using uninitialized variables in 356 member initializer lists ([51]PR19808) 357 * [52]-Wint-in-bool-context is now disabled when instantiating a 358 template ([53]git) 359 * Stricter checking of attributes on friend declarations: if a friend 360 declaration has an attribute, that declaration must be a 361 definition. Moreover, a C++11 attribute cannot appear in the middle 362 of the decl-specifier-seq. ([54]PR99032) 363 * New warning options for C++ language mismatches: 364 -Wc++11-extensions, -Wc++14-extensions, -Wc++17-extensions, 365 -Wc++20-extensions, and -Wc++23-extensions. They are enabled by 366 default and can be used to control existing pedwarns about 367 occurrences of new C++ constructs in code using an old C++ standard 368 dialect. 369 * New warning [55]-Wmissing-requires warns about missing requires 370 ([56]git) 371 * The existing std::is_constant_evaluated in if warning was extended 372 to warn in more cases ([57]PR100995) 373 * [58]-Waddress has been enhanced so that it now warns about, for 374 instance, comparing the address of a nonstatic member function to 375 null ([59]PR102103) 376 * Errors about narrowing are no longer hidden if they occur in system 377 headers 378 * Ordered comparison of null pointers is now rejected ([60]PR99701) 379 * Anonymous structs with bases are now rejected ([61]git) 380 * The compiler rejects taking the address of an immediate member 381 function ([62]PR102753) 382 * The compiler has support for C++20 383 __cpp_lib_is_pointer_interconvertible and 384 __cpp_lib_is_layout_compatible to help the C++ library implement 385 [63]P0466, Layout-compatibility and Pointer-interconvertibility 386 Traits ([64]PR101539) 387 * Memory usage of constraint subsumption has been improved 388 ([65]PR100828) 389 * constinit thread_local variables are optimized better 390 ([66]PR101786) 391 * Support for C++17 std::hardware_destructive_interference_size was 392 added, along with the [67]-Winterference-size warning ([68]git) 393 * Many bugs in the CTAD handling have been fixed ([69]PR101344, 394 [70]PR101883, [71]PR89062, [72]PR101233, [73]PR88252, [74]PR86439, 395 [75]PR98832, [76]PR102933 ...) 396 * Two-stage name lookup for dependent operator expressions has been 397 corrected ([77]PR51577) 398 * Several issues with constrained variable templates have been fixed 399 ([78]PR98486) 400 * The compiler performs less instantiating when doing speculative 401 constant evaluation ([79]git) 402 * Various diagnostic improvements; e.g., a more precise caret 403 location for pointer-to-member expressions 404 * The new -fconstexpr-fp-except flag allows IEC559 floating point 405 exceptions in constant-expressions. 406 407 Runtime Library (libstdc++) 408 409 * Improved experimental C++20 support, including: 410 + std::vector, std::basic_string, std::optional, and 411 std::variant can be used in constexpr functions. 412 + std::make_shared for arrays with default initialization, and 413 std::atomic<std::shared_ptr<T>>. 414 + Layout-compatibility and pointer-interconvertibility traits. 415 * Improved experimental C++23 support, including: 416 + Monadic operations for std::optional. 417 + std::expected 418 + std::move_only_function 419 + <spanstream> 420 + std::basic_string::resize_and_overwrite 421 + std::unique_ptr can be used in constexpr functions. 422 + <stacktrace> (not built by default, requires linking to an 423 extra library). 424 + <stdatomic.h> 425 + std::invoke_r 426 + constexpr std::type_info::operator== 427 428 D 429 430 * New features: 431 + Support for the D programming language has been updated to 432 version 2.100.1 of the language and run-time library. Full 433 changelog for this release and previous releases can be found 434 on the [80]dlang.org website. 435 + On supported targets, the __traits(compiles) expression can 436 now be used to determine whether a target-specific built-in is 437 available without error during CTFE ([81]PR101127). 438 + Functions annotated with pragma(inline, true) are now compiled 439 into every module where they are used from ([82]PR106563). 440 + Partial support for directly importing C99 sources into a D 441 compilation ([83]ImportC) has been added to the language. A 442 notable missing feature is support for preprocessing C 443 imports, which can be worked around by preprocessing all C 444 sources used for importing ahead of time. 445 * New language options: 446 + -fcheck=, enables or disables the code generation of specific 447 run-time contract checks. 448 + -fcheckaction=, controls the run-time behavior on an assert, 449 array bounds check, or final switch contract failure. The 450 default is -fcheckaction=throw. 451 + -fdump-c++-spec=, dumps all compiled extern(C++) declarations 452 as C++ code to the given file. The supplementary option 453 -fdump-c++-spec-verbose turns on emission of comments for 454 ignored declarations in the generated spec. 455 + -fextern-std=, controls which C++ standard extern(C++) 456 declarations are compiled to be compatible with. The default 457 is -fextern-std=c++17. 458 + -fpreview=, added to enable upcoming D language features in 459 the compiler. 460 + -frevert=, added to revert D language changes to support older 461 D codebases that need more time to transition. 462 + -fsave-mixins=, saves mixins expanded at compile-time to a 463 file. 464 * Deprecated and removed features: 465 + The -Wtemplates compiler switch has been removed, as it had 466 been superceded by -ftransition=templates, which more 467 accurately reports on which templates have been instantiated. 468 + The -ftransition=dip25 and -ftransition=dip1000 compiler 469 switches have been renamed to -fpreview=dip25 and 470 -fpreview=dip1000. 471 472 Fortran 473 474 * WG5/N1942, "TS 29113 Further Interoperability of Fortran with C", 475 is now fully supported. In addition to implementing previously 476 missing functionality, such as support for character arguments of 477 length greater than one in functions marked bind(c) and gaps in the 478 handling for assumed-rank arrays, numerous other bugs have been 479 fixed, and an extensive set of new conformance test cases has been 480 added. 481 * GCC 12 now uses OPERATION as the name of the function to the 482 CO_REDUCE intrinsic for the pairwise reduction, thus conforming to 483 the Fortran 2018 standard. Previous versions used OPERATOR which 484 conforms to TS 18508. 485 * On POWER systems which support it, the -mabi=ieeelongdouble option 486 now selects the IEEE 128-bit floating point format for 487 REAL(KIND=16). R16_IBM and R16_IEEE have been added to the 488 -fconvert option, the CONVERT specifier of the OPEN statement and 489 the GFORTRAN_CONVERT_UNIT environment variable. 490 491 Go 492 493 * GCC 12 provides a complete implementation of the Go 1.18 user 494 packages. 495 * Although Go 1.18 includes support for generic programming, that 496 support is not yet available in GCC. 497 498 libgccjit 499 500 * The libgccjit API gained 30 new entry points: 501 + 17 new "reflection" entry points for querying functions and 502 types ([84]LIBGCCJIT_ABI_16) 503 + [85]gcc_jit_lvalue_set_tls_model for supporting thread-local 504 variables ([86]LIBGCCJIT_ABI_17) 505 + [87]gcc_jit_lvalue_set_link_section for setting the link 506 section of global variables, analogous to 507 [88]__attribute__((section(".section"))) 508 ([89]LIBGCCJIT_ABI_18) 509 + 4 new entry points for initializing global variables and 510 creating constructors for rvalues ([90]LIBGCCJIT_ABI_19) 511 + Support for sized integer types, including 128-bit integers 512 and helper functions for such types ([91]LIBGCCJIT_ABI_20) 513 + [92]gcc_jit_context_new_bitcast for reinterpreting the bits of 514 an rvalue as a different type ([93]LIBGCCJIT_ABI_21) 515 + [94]gcc_jit_lvalue_set_register_name for setting a specific 516 register for a variable ([95]LIBGCCJIT_ABI_22) 517 + [96]gcc_jit_context_set_bool_print_errors_to_stderr 518 ([97]LIBGCCJIT_ABI_23) 519 + 2 new entry points for setting the alignment of a variable 520 ([98]LIBGCCJIT_ABI_24) 521 * libgccjit has gained support for the use of various atomic builtins 522 ([99]PR96066, [100]PR96067) 523 * [101]gcc_jit_context_new_cast is now able to handle truncation and 524 extension between different integer types ([102]PR95498) 525 526 New Targets and Target Specific Improvements 527 528 AArch64 & arm 529 530 * Newer revisions of the Arm Architecture are supported as arguments 531 to the -march option: armv8.7-a, armv8.8-a, armv9-a. 532 * The Arm Cortex-A510 CPU is now supported through the cortex-a510 533 argument to the -mcpu and -mtune options. 534 * GCC can now auto-vectorize operations performing sign-differing 535 dot-product operations, taking advantage of instructions in the 536 Advanced SIMD (AArch64/AArch32) and SVE (AArch64) instruction sets. 537 538 AArch64 539 540 * A number of new CPUs are supported through the -mcpu and -mtune 541 options (GCC identifiers in parentheses). 542 + Ampere-1 (ampere1). 543 + Arm Cortex-A710 (cortex-a710). 544 + Arm Cortex-X2 (cortex-x2). 545 * The 64-byte atomic load/store intrinsics to accelerator memory from 546 the [103]2020 Arm Architecture extensions are supported through the 547 +ls64 option extension. 548 * Initial code generation support is supported for hardware 549 instructions used to accelerate the memcpy,memmove and memset 550 standard functions. These instructions can be generated when 551 compiling with the +mopsoption extension. 552 * The ACLE Advanced SIMD intrinsics accessible through the arm_neon.h 553 header have been significantly reimplemented and generate 554 higher-performing code than previous GCC versions. 555 * The option -mtune=neoverse-512tvb is added to tune for Arm Neoverse 556 cores that have a total vector bandwidth of 512 bits. Please refer 557 to the documentation for more details. 558 559 AMD Radeon (GCN) 560 561 * Debug experience with ROCGDB has been improved. 562 * Support for the type __int128_t/integer(kind=16) was added. 563 * For offloading, the limitation of using only one wavefront per 564 compute unit (CU) has been lifted. Up to 40 workgroups per CU and 565 16 wavefronts per workgroup are supported (up to a limit of 40 566 wavefronts in total, per CU). Additionally, the number of used 567 wavefronts and workgroups was tuned for performance. 568 569 arm 570 571 * Support is added for accessing the stack canary value via the TLS 572 register through the -fstack-protector-guard=tls and 573 -mstack-protector-guard-offset= options. This intended for use in 574 Linux kernel development. Please refer to the documentation for 575 more details. 576 577 BPF 578 579 * Support for CO-RE (compile-once, run-everywhere) has been added to 580 the BPF backend. CO-RE allows to compile portable BPF programs that 581 are able to run among different versions of the Linux kernel. 582 583 IA-32/x86-64 584 585 * New ISA extension support for Intel AVX512-FP16 was added. 586 AVX512-FP16 intrinsics are available via the -mavx512fp16 compiler 587 switch. 588 * For both C and C++ the _Float16 type is supported on x86 systems 589 with SSE2 enabled. Without {-mavx512fp16}, all operations will be 590 emulated in software and float instructions. 591 * Mitigation against straight line speculation (SLS) for function 592 return and indirect jump is supported via 593 -mharden-sls=[none|all|return|indirect-jmp]. 594 * Add CS prefix to call and jmp to indirect thunk with branch target 595 in r8-r15 registers via -mindirect-branch-cs-prefix. 596 * Always use global offset table (GOT) to access external data and 597 function symbols when the new -mno-direct-extern-access 598 command-line option is specified. 599 600 LoongArch 601 602 * Support for the LoongArch architecture instruction set has been 603 added. 604 * The Loongson CPU codename LA464 and LoongArch 64-bit generic CPU 605 codename loongarch64 are supported through the -march= and -mtune= 606 options (GCC identifiers in parentheses). 607 + Loongson LA464 core (la464). 608 + LoongArch 64-bit generic core (loongarch64). 609 610 MIPS 611 612 * The ABI passing arguments containing zero-width fields (for 613 example, C/C++ zero-width bit-fields, GNU C/C++ zero-length arrays, 614 and GNU C empty structs) has changed. Now a zero-width field will 615 not prevent an aligned 64-bit floating-point field next to it from 616 being passed through FPR. This is compatible with LLVM, but 617 incompatible with previous GCC releases. GCC 12 on MIPS will report 618 such incompatibilities as an inform unless -Wno-psabi is used. 619 * The ABI returning values containing C++17 empty bases has changed. 620 Now an empty base will not prevent an aggregate containing only one 621 or two floating-point fields from being returned through FPR. This 622 is compatible with GCC 6 and earlier, but incompatible with GCC 7 623 through 11. GCC 12 on MIPS will report such incompatibilities as an 624 inform unless -Wno-psabi is used. 625 626 NVPTX 627 628 * The -march flag has been added. The -misa flag is now considered an 629 alias of the -march flag. 630 * Support for PTX ISA target architectures sm_53, sm_70, sm_75 and 631 sm_80 has been added. These can be specified using the -march flag. 632 * The default PTX ISA target architecture has been set back to sm_30, 633 to fix support for sm_30 boards. 634 * The -march-map flag has been added. The -march-map value will be 635 mapped to an valid -march flag value. For instance, 636 -march-map=sm_50 maps to -march=sm_35. This can be used to specify 637 that generated code is to be executed on a board with at least some 638 specific compute capability, without having to know the valid 639 values for the -march flag. 640 * The -mptx flag has been added to specify the PTX ISA version for 641 the generated code; permitted values are 3.1 (matches previous GCC 642 versions), 6.0, 6.3, and 7.0. If not specified, the used version is 643 the minimal version required for -march but at least 6.0. 644 * An mptx-3.1 multilib was added. This allows using older drivers 645 which do not support PTX ISA version 6.0. 646 * The new __PTX_SM__ predefined macro allows code to check the PTX 647 ISA target architecture being targeted by the compiler. 648 * The new __PTX_ISA_VERSION_MAJOR__ and __PTX_ISA_VERSION_MINOR__ 649 predefined macros allows code to check the PTX ISA version being 650 targeted by the compiler. 651 652 PowerPC / PowerPC64 / RS6000 653 654 * The internal implementation of Power's target-specific built-in 655 functions has been rewritten to be easier and less error-prone to 656 maintain. Every attempt has been made to ensure that the new 657 behavior matches the old behavior, but inevitably some bugs can be 658 expected. Please report any problems via [104]GCC Bugzilla. 659 * The built-in functions __builtin_get_texasr, __builtin_get_texasru, 660 __builtin_get_tfhar, __builtin_get_tfiar, __builtin_set_texasr, 661 __builtin_set_texasru, __builtin_set_tfhar, and __builtin_set_tfiar 662 now behave as documented in all supported configurations. On prior 663 releases, the arguments and return values of these functions were 664 treated as unsigned long long instead of as unsigned long, when the 665 options -m32 -mpowerpc64 were in effect. 666 * The overloaded built-in functions vec_cntlz_lsbb and vec_cnttz_lsbb 667 now behave as documented. On prior releases, these built-in 668 functions had incorrect semantics on little-endian targets. 669 670 PRU 671 672 * The [105]__regio_symbol variable qualifier has been added. It 673 allows easier access in C programs to the __R30 and __R31 CPU I/O 674 registers. 675 676 RISC-V 677 678 * Default ISA spec version was bump to 20191213, more detail see this 679 [106]announcement 680 * New ISA extension support for zba, zbb, zbc, zbs was added. 681 * New ISA extension support for vector and scalar crypto was added, 682 only support architecture testing marco and -march= parsing. 683 * The option -mtune=thead-c906 is added to tune for T-HEAD c906 684 cores. 685 * libstdc++ no longer attempts to detect built-in atomics. 686 Distributions that have out-of-tree workarounds for -latomic should 687 check their ABIs again. 688 689 Operating Systems 690 691 Improvements to Static Analyzer 692 693 * The analyzer has gained a 694 [107]-Wanalyzer-use-of-uninitialized-value warning, similar to 695 [108]-Wuninitialized and [109]-Wmaybe-uninitialized, but based on 696 an interprocedural path-sensitive analysis ([110]PR95006). 697 Such warnings are not disabled by the new 698 [111]-ftrivial-auto-var-init (see below), as the latter is 699 considered a mitigation option. 700 * [112]-Wanalyzer-write-to-const and 701 [113]-Wanalyzer-write-to-string-literal will now check for 702 [114]__attribute__ ((access, ....)) on calls to externally-defined 703 functions, and complain about read-only regions pointed to by 704 arguments marked with a write_only or read_write attribute 705 ([115]PR104793). 706 * The analyzer's "taint" mode, activated by 707 [116]-fanalyzer-checker=taint (in addition to [117]-fanalyzer), has 708 gained four new taint-based warnings: 709 + [118]-Wanalyzer-tainted-allocation-size for e.g. 710 attacker-controlled malloc and alloca, 711 + [119]-Wanalyzer-tainted-divisor for detecting where an 712 attacker can inject a divide-by-zero, 713 + [120]-Wanalyzer-tainted-offset for attacker-controlled pointer 714 offsets, 715 + [121]-Wanalyzer-tainted-size for attacker-controlled values 716 being used as a size parameter to calls to memset or to 717 functions marked with [122]__attribute__ ((access, ....)). 718 The existing [123]-Wanalyzer-tainted-array-index has been reworded 719 to talk about "attacker-controlled" rather than "tainted" values, 720 for consistency with the new warnings. 721 A new [124]__attribute__ ((tainted_args)) has been added to the C 722 and C++ front ends, usable on functions, and on function pointer 723 callback fields in structs. The analyzer's taint mode will treat 724 all parameters and buffers pointed to by parameters of such 725 functions as being attacker-controlled, such as for annotating 726 system calls in an operating system kernel as being an "attack 727 surface". 728 * The analyzer now respects [125]__attribute__((const)): it will 729 treat such functions as returning the same value when given the 730 same inputs ([126]PR104434), and as having no side effects 731 ([127]PR104576). 732 * The analyzer is now able to split its analysis into multiple 733 execution paths in places where there isn't a split in the control 734 flow graph. For example, it now handles realloc calls by splitting 735 the execution path into three possible outcomes for the call: 736 + failure, returning NULL 737 + success, growing the buffer in-place without moving it 738 + success, allocating a new buffer, copying the content of the 739 old buffer to it, and freeing the old buffer 740 * The analyzer's interprocedural path exploration logic is now able 741 to track calls through function pointers. 742 * The analyzer now makes the assumption that if we know PTR is 743 non-NULL, then (PTR + OFFSET) is also non-NULL. This isn't strictly 744 true, but eliminates false positives in practice ([128]PR101962). 745 * The analyzer has gained some initial support for inline assembler 746 code. This is extremely limited, and is purely to help suppress 747 false positives when analyzing the Linux kernel, which makes heavy 748 use of inline assembler ([129]PR101570). 749 * The way the analyzer tracks the state of memory along an execution 750 path has been improved in various ways for GCC 12: 751 + An optimization for representing bulk updates to memory (e.g. 752 zero fills) has been removed as it never worked well. In GCC 753 12 it has been replaced with a simpler and more accurate 754 approach, eliminating many false positives ([130]PR95006). 755 + Various optimizations have been added, speeding up the 756 analysis on a particularly problematic source file from 4 757 minutes down to 17 seconds ([131]PR104943, [132]PR104954, and 758 [133]PR104955). 759 + The analyzer now tracks the sizes of dynamically-allocated 760 regions, both on the heap (via malloc etc) and stack (via 761 alloca), though none of the analyzer warnings make use of this 762 yet in GCC 12. 763 * The analyzer's handling of switch statements has been rewritten, 764 fixing various bugs. 765 766 Other significant improvements 767 768 Eliminating uninitialized variables 769 770 * GCC can now [134]initialize all stack variables implicitly, 771 including padding. This is intended to eliminate all classes of 772 uninitialized stack variable flaws. Lack of explicit initialization 773 will still warn when [135]-Wuninitialized is active. For best 774 debugging, use of the new command-line option 775 [136]-ftrivial-auto-var-init=pattern can be used to fill variables 776 with a repeated 0xFE pattern, which tends to illuminate many bugs 777 (e.g. pointers receive invalid addresses, sizes and indices are 778 very large). For best production results, the new command-line 779 option [137]-ftrivial-auto-var-init=zero can be used to fill 780 variables with 0x00, which tends to provide a safer state for bugs 781 (e.g. pointers are NULL, strings are NUL filled, and sizes and 782 indices are 0). 783 784 Debugging formats 785 786 * GCC can now generate debugging information in [138]CTF, a 787 lightweight debugging format that provides information about C 788 types and the association between functions and data symbols and 789 types. This format is designed to be embedded in ELF files and to 790 be very compact and simple. A new command-line option -gctf enables 791 the generation of CTF. 792 * GCC can now generate debugging information in BTF. This is a 793 debugging format mainly used in BPF programs and the Linux kernel. 794 The compiler can generate BTF for any target, when enabled with the 795 command-line option -gbtf 796 797 GCC 12.1 798 799 This is the [139]list of problem reports (PRs) from GCC's bug tracking 800 system that are known to be fixed in the 12.1 release. This list might 801 not be complete (that is, it is possible that some PRs that have been 802 fixed are not listed here). 803 804 GCC 12.2 805 806 This is the [140]list of problem reports (PRs) from GCC's bug tracking 807 system that are known to be fixed in the 12.2 release. This list might 808 not be complete (that is, it is possible that some PRs that have been 809 fixed are not listed here). 810 811 Target Specific Changes 812 813 LoongArch 814 815 * The default setting of -m[check|no-check]-zero-division is changed 816 for optimized code. Now -mno-check-zero-division is the default for 817 all optimization levels but -O0 and -Og. The old behavior can be 818 obtained by explicitly passing -mcheck-zero-division to GCC. 819 820 GCC 12.3 821 822 Target Specific Changes 823 824 x86-64 825 826 * GCC now supports AMD CPUs based on the znver4 core via 827 -march=znver4. The switch makes GCC consider using 512 bit vectors 828 when auto-vectorizing. 829 830 This is the [141]list of problem reports (PRs) from GCC's bug tracking 831 system that are known to be fixed in the 12.3 release. This list might 832 not be complete (that is, it is possible that some PRs that have been 833 fixed are not listed here). 834 835 GCC 12.4 836 837 Note: GCC 12.4 has not been released yet, so this section is a 838 work-in-progress. 839 840 This is the [142]list of problem reports (PRs) from GCC's bug tracking 841 system that are known to be fixed in the 12.4 release. This list might 842 not be complete (that is, it is possible that some PRs that have been 843 fixed are not listed here). 844 845 846 For questions related to the use of GCC, please consult these web 847 pages and the [143]GCC manuals. If that fails, the 848 [144]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 849 web pages and the development of GCC are welcome on our developer 850 list at [145]gcc (a] gcc.gnu.org. All of [146]our lists have public 851 archives. 852 853 Copyright (C) [147]Free Software Foundation, Inc. Verbatim copying and 854 distribution of this entire article is permitted in any medium, 855 provided this notice is preserved. 856 857 These pages are [148]maintained by the GCC team. Last modified 858 2023-05-08. 859 860 References 861 862 1. http://gcc.gnu.org/gcc-12/porting_to.html 863 2. http://gcc.gnu.org/onlinedocs/index.html#current 864 3. https://gcc.gnu.org/PR102024 865 4. https://gcc.gnu.org/PR42217 866 5. http://gcc.gnu.org/gcc-12/changes.html#mips_zero_width_fields 867 6. https://gcc.gnu.org/install/specific.html 868 7. https://clang.llvm.org/docs/ShadowCallStack.html 869 8. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Instrumentation-Options.html#index-fsanitize_003dshadow-call-stack 870 9. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/libgomp/OpenMP-Implementation-Status.html 871 10. https://www.openacc.org/ 872 11. https://gcc.gnu.org/wiki/OpenACC/Implementation%20Status#status-12 873 12. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/libgomp/Enabling-OpenACC.html 874 13. http://gcc.gnu.org/gcc-12/changes.html#amdgcn 875 14. http://gcc.gnu.org/gcc-12/changes.html#nvptx 876 15. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Optimize-Options.html#index-param 877 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https://gcc.gnu.org/PR101233 934 73. https://gcc.gnu.org/PR88252 935 74. https://gcc.gnu.org/PR86439 936 75. https://gcc.gnu.org/PR98832 937 76. https://gcc.gnu.org/PR102933 938 77. https://gcc.gnu.org/PR51577 939 78. https://gcc.gnu.org/PR98486 940 79. https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=1595fe44 941 80. https://dlang.org/changelog/2.100.1.html 942 81. https://gcc.gnu.org/PR101127 943 82. https://gcc.gnu.org/PR106563 944 83. https://dlang.org/spec/importc.html 945 84. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-16 946 85. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/expressions.html#c.gcc_jit_lvalue_set_tls_model 947 86. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-17 948 87. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/expressions.html#c.gcc_jit_lvalue_set_link_section 949 88. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Common-Variable-Attributes.html#index-section-variable-attribute 950 89. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-18 951 90. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-19 952 91. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-20 953 92. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/expressions.html#c.gcc_jit_context_new_bitcast 954 93. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-21 955 94. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/expressions.html#c.gcc_jit_lvalue_set_register_name 956 95. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-22 957 96. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/contexts.html#c.gcc_jit_context_set_bool_print_errors_to_stderr 958 97. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-23 959 98. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/compatibility.html#libgccjit-abi-24 960 99. https://gcc.gnu.org/PR96066 961 100. https://gcc.gnu.org/PR96067 962 101. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/jit/topics/expressions.html#c.gcc_jit_context_new_cast 963 102. https://gcc.gnu.org/PR95498 964 103. https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/arm-a-profile-architecture-developments-2020 965 104. https://gcc.gnu.org/bugzilla/ 966 105. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Named-Address-Spaces.html#PRU-Named-Address-Spaces 967 106. https://groups.google.com/a/groups.riscv.org/g/sw-dev/c/aE1ZeHHCYf4 968 107. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-use-of-uninitialized-value 969 108. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Warning-Options.html#index-Wuninitialized 970 109. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Warning-Options.html#index-Wmaybe-uninitialized 971 110. https://gcc.gnu.org/PR95006 972 111. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Optimize-Options.html#index-ftrivial-auto-var-init 973 112. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-write-to-const 974 113. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-write-to-string-literal 975 114. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Common-Function-Attributes.html 976 115. https://gcc.gnu.org/PR104793 977 116. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-fanalyzer-checker 978 117. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-fanalyzer 979 118. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-tainted-allocation-size 980 119. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-tainted-divisor 981 120. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-tainted-offset 982 121. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-tainted-size 983 122. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Common-Function-Attributes.html 984 123. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-tainted-array-index 985 124. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Common-Function-Attributes.html#index-tainted_005fargs-function-attribute 986 125. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Common-Function-Attributes.html#index-const-function-attribute 987 126. https://gcc.gnu.org/PR104434 988 127. https://gcc.gnu.org/PR104576 989 128. https://gcc.gnu.org/PR101962 990 129. https://gcc.gnu.org/PR101570 991 130. https://gcc.gnu.org/PR95006 992 131. https://gcc.gnu.org/PR104943 993 132. https://gcc.gnu.org/PR104954 994 133. https://gcc.gnu.org/PR104955 995 134. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Optimize-Options.html#index-ftrivial-auto-var-init 996 135. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Warning-Options.html#index-Wuninitialized 997 136. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Optimize-Options.html#index-ftrivial-auto-var-init 998 137. https://gcc.gnu.org/onlinedocs/gcc-12.1.0/gcc/Optimize-Options.html#index-ftrivial-auto-var-init 999 138. https://ctfstd.org/ 1000 139. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=12.0 1001 140. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=12.2 1002 141. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=12.3 1003 142. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=12.4 1004 143. https://gcc.gnu.org/onlinedocs/ 1005 144. mailto:gcc-help (a] gcc.gnu.org 1006 145. mailto:gcc (a] gcc.gnu.org 1007 146. https://gcc.gnu.org/lists.html 1008 147. https://www.fsf.org/ 1009 148. https://gcc.gnu.org/about.html 1010 ====================================================================== 1011 http://gcc.gnu.org/gcc-11/index.html 1012 1013 GCC 11 Release Series 1014 1015 April 21, 2022 1016 1017 The GCC developers are pleased to announce the release of GCC 11.3. 1018 1019 This release is a bug-fix release, containing fixes for regressions in 1020 GCC 11.2 relative to previous releases of GCC. 1021 1022 Release History 1023 1024 GCC 11.3 1025 April 21, 2022 ([1]changes, [2]documentation) 1026 1027 GCC 11.2 1028 July 28, 2021 ([3]changes, [4]documentation) 1029 1030 GCC 11.1 1031 April 27, 2021 ([5]changes, [6]documentation) 1032 1033 References and Acknowledgements 1034 1035 GCC used to stand for the GNU C Compiler, but since the compiler 1036 supports several other languages aside from C, it now stands for the 1037 GNU Compiler Collection. 1038 1039 A list of [7]successful builds is updated as new information becomes 1040 available. 1041 1042 The GCC developers would like to thank the numerous people that have 1043 contributed new features, improvements, bug fixes, and other changes as 1044 well as test results to GCC. This [8]amazing group of volunteers is 1045 what makes GCC successful. 1046 1047 For additional information about GCC please refer to the [9]GCC project 1048 web site or contact the [10]GCC development mailing list. 1049 1050 To obtain GCC please use [11]our mirror sites or [12]our version 1051 control system. 1052 1053 1054 For questions related to the use of GCC, please consult these web 1055 pages and the [13]GCC manuals. If that fails, the 1056 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1057 web pages and the development of GCC are welcome on our developer 1058 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 1059 archives. 1060 1061 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 1062 distribution of this entire article is permitted in any medium, 1063 provided this notice is preserved. 1064 1065 These pages are [18]maintained by the GCC team. Last modified 1066 2022-10-26. 1067 1068 References 1069 1070 1. http://gcc.gnu.org/gcc-11/changes.html 1071 2. http://gcc.gnu.org/onlinedocs/11.3.0/ 1072 3. http://gcc.gnu.org/gcc-11/changes.html 1073 4. http://gcc.gnu.org/onlinedocs/11.2.0/ 1074 5. http://gcc.gnu.org/gcc-11/changes.html 1075 6. http://gcc.gnu.org/onlinedocs/11.1.0/ 1076 7. http://gcc.gnu.org/gcc-11/buildstat.html 1077 8. http://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Contributors.html 1078 9. http://gcc.gnu.org/index.html 1079 10. mailto:gcc (a] gcc.gnu.org 1080 11. http://gcc.gnu.org/mirrors.html 1081 12. http://gcc.gnu.org/git.html 1082 13. https://gcc.gnu.org/onlinedocs/ 1083 14. mailto:gcc-help (a] gcc.gnu.org 1084 15. mailto:gcc (a] gcc.gnu.org 1085 16. https://gcc.gnu.org/lists.html 1086 17. https://www.fsf.org/ 1087 18. https://gcc.gnu.org/about.html 1088 ====================================================================== 1089 http://gcc.gnu.org/gcc-11/changes.html 1090 1091 GCC 11 Release Series 1092 Changes, New Features, and Fixes 1093 1094 This page is a "brief" summary of some of the huge number of 1095 improvements in GCC 11. You may also want to check out our [1]Porting 1096 to GCC 11 page and the [2]full GCC documentation. 1097 1098 Caveats 1099 1100 * The default mode for C++ is now -std=gnu++17 instead of 1101 -std=gnu++14. Note that [3]C++17 changes to template template 1102 parameter matching can be disabled independently of other features 1103 with -fno-new-ttp-matching. 1104 * When building GCC itself, the host compiler must now support C++11, 1105 rather than C++98. In particular bootstrapping GCC 11 using an 1106 older version of GCC requires a binary of GCC 4.8 or later, rather 1107 than of GCC 3.4 or later as was the case for bootstrapping GCC 10. 1108 * Naming and location of auxiliary and dump output files changed. If 1109 you compile multiple input files in a single command, if you enable 1110 Link Time Optimization, or if you use -dumpbase, -dumpdir, 1111 -save-temps=*, and you expect any file other than the primary 1112 output file(s) to be created as a side effect, watch out for 1113 improvements and a few surprises. See [4]the patch, particularly 1114 its textual description, for more details about the changes. 1115 * -gsplit-dwarf no longer enables debug info generation on its own 1116 but requires a separate -g for this. 1117 * The libstdc++ configure option --enable-cheaders=c_std is 1118 deprecated and will be removed in a future release. It should be 1119 possible to use --enable-cheaders=c_global (the default) with no 1120 change in behaviour. 1121 * The front end for compiling BRIG format of Heterogeneous System 1122 Architecture Intermediate Language (HSAIL) has been deprecated and 1123 will likely be removed in a future release. 1124 * Some short options of the gcov tool have been renamed: -i to -j and 1125 -j to -H. 1126 1127 General Improvements 1128 1129 * [5]ThreadSanitizer improvements to support alternative runtimes and 1130 environments. The [6]Linux Kernel Concurrency Sanitizer (KCSAN) is 1131 now supported. 1132 + Add --param tsan-distinguish-volatile to optionally emit 1133 instrumentation distinguishing volatile accesses. 1134 + Add --param tsan-instrument-func-entry-exit to optionally 1135 control if function entries and exits should be instrumented. 1136 * In previous releases of GCC, the "column numbers" emitted in 1137 diagnostics were actually a count of bytes from the start of the 1138 source line. This could be problematic, both because of: 1139 + multibyte characters (requiring more than one byte to encode), 1140 and 1141 + multicolumn characters (requiring more than one column to 1142 display in a monospace font) 1143 For example, the character p ("GREEK SMALL LETTER PI (U+03C0)") 1144 occupies one column, and its UTF-8 encoding requires two bytes; the 1145 character 🙂 ("SLIGHTLY SMILING FACE (U+1F642)") occupies 1146 two columns, and its UTF-8 encoding requires four bytes. 1147 In GCC 11 the column numbers default to being column numbers, 1148 respecting multi-column characters. The old behavior can be 1149 restored using a new option [7]-fdiagnostics-column-unit=byte. 1150 There is also a new option [8]-fdiagnostics-column-origin=, 1151 allowing the pre-existing default of the left-hand column being 1152 column 1 to be overridden if desired (e.g. for 0-based columns). 1153 The output of [9]-fdiagnostics-format=json has been extended to 1154 supply both byte counts and column numbers for all source 1155 locations. 1156 Additionally, in previous releases of GCC, tab characters in the 1157 source would be emitted verbatim when quoting source code, but be 1158 prefixed with whitespace or line number information, leading to 1159 misalignments in the resulting output when compared with the actual 1160 source. Tab characters are now printed as an appropriate number of 1161 spaces, using the [10]-ftabstop option (which defaults to 8 spaces 1162 per tab stop). 1163 * Introduce [11]Hardware-assisted AddressSanitizer support. This 1164 sanitizer currently only works for the AArch64 target. It helps 1165 debug address problems similarly to [12]AddressSanitizer but is 1166 based on partial hardware assistance and provides probabilistic 1167 protection to use less RAM at run time. [13]Hardware-assisted 1168 AddressSanitizer is not production-ready for user space, and is 1169 provided mainly for use compiling the Linux Kernel. 1170 To use this sanitizer the command line arguments are: 1171 + -fsanitize=hwaddress to instrument userspace code. 1172 + -fsanitize=kernel-hwaddress to instrument kernel code. 1173 * For targets that produce DWARF debugging information GCC now 1174 defaults to [14]DWARF version 5 (with the exception of VxWorks and 1175 Darwin/Mac OS X which default to version 2 and AIX which defaults 1176 to version 4). This can produce up to 25% more compact debug 1177 information compared to earlier versions. 1178 To take full advantage of DWARF version 5 GCC needs to be built 1179 against binutils version 2.35.2 or higher. When GCC is built 1180 against earlier versions of binutils GCC will still emit DWARF 1181 version 5 for most debuginfo data, but will generate version 4 1182 debug line tables (even when explicitly given -gdwarf-5). 1183 The following debug information consumers can process DWARF version 1184 5: 1185 + GDB 8.0, or higher 1186 + valgrind 3.17.0 1187 + elfutils 0.172, or higher (for use with systemtap, 1188 dwarves/pahole, perf and libabigail) 1189 + dwz 0.14 1190 Programs embedding libbacktrace are urged to upgrade to the version 1191 shipping with GCC 11. 1192 To make GCC 11 generate an older DWARF version use -g together with 1193 -gdwarf-2, -gdwarf-3 or -gdwarf-4. 1194 * Vectorizer improvements: 1195 + The straight-line code vectorizer now considers the whole 1196 function when vectorizing and can handle opportunities 1197 crossing CFG merges and backedges. 1198 * A series of conditional expressions that compare the same variable 1199 can be transformed into a switch statement if each of them contains 1200 a comparison expression. Example: 1201 int IsHTMLWhitespace(int aChar) { 1202 return aChar == 0x0009 || aChar == 0x000A || 1203 aChar == 0x000C || aChar == 0x000D || 1204 aChar == 0x0020; 1205 } 1206 1207 This statement can be transformed into a switch statement and then 1208 expanded into a bit-test. 1209 * New command-line options: 1210 + [15]-fbit-tests, enabled by default, can be used to enable or 1211 disable switch expansion using bit-tests. 1212 * Inter-procedural optimization improvements: 1213 + A new IPA-modref pass was added to track side effects of 1214 function calls and improve precision of points-to-analysis. 1215 The pass can be controlled by the [16]-fipa-modref option. 1216 + The identical code folding pass (controlled by [17]-fipa-icf) 1217 was significantly improved to increase the number of unified 1218 functions and to reduce compile-time memory use. 1219 + IPA-CP (Interprocedural constant propagation) heuristics 1220 improved its estimation of potential usefulness of known loop 1221 bounds and strides by taking the estimated frequency of these 1222 loops into account. 1223 * Link-time optimization improvements: 1224 + The LTO bytecode format was optimized for smaller object files 1225 and faster streaming. 1226 + Memory allocation of the linking stage was improved to reduce 1227 peak memory use. 1228 * Profile driven optimization improvements: 1229 + Using [18]-fprofile-values, was improved by tracking more 1230 target values for e.g. indirect calls. 1231 + GCOV data file format outputs smaller files by representing 1232 zero counters in a more compact way. 1233 1234 New Languages and Language specific improvements 1235 1236 * GCC 11 adds support for non-rectangular loop nests in OpenMP 1237 constructs and the allocator routines of [19]OpenMP 5.0, including 1238 initial allocate clause support in C/C++. The OMP_TARGET_OFFLOAD 1239 environment variable and the active-levels routines are now 1240 supported. For C/C++, the declare variant and map support has been 1241 extended. For Fortran, OpenMP 4.5 is now fully supported and OpenMP 1242 5.0 support has been extended, including the following features 1243 which were before only available in C and C++: order(concurrent), 1244 device_type, memorder-clauses for flush, lastprivate with 1245 conditional modifier, atomic construct and reduction clause 1246 extensions of OpenMP 5.0, if clause with simd and cancel modifiers, 1247 target data without map clause, and limited support for the 1248 requires construct. 1249 * Version 2.6 of the [20]OpenACC specification continues to be 1250 maintained and improved in the C, C++ and Fortran compilers. See 1251 the [21]implementation status section on the OpenACC wiki page and 1252 the [22]run-time library documentation for further information. 1253 1254 C family 1255 1256 * New attributes: 1257 + The [23]no_stack_protector attribute has been added to mark 1258 functions which should not be instrumented with stack 1259 protection (-fstack-protector). 1260 + The existing [24]malloc attribute has been extended so that it 1261 can be used to identify allocator/deallocator API pairs. A 1262 pair of new [25]-Wmismatched-dealloc and 1263 [26]-Wmismatched-new-delete warnings will complain about 1264 mismatched calls, and [27]-Wfree-nonheap-object about 1265 deallocation calls with pointers not obtained from allocation 1266 functions. Additionally, the static analyzer will use these 1267 attributes when checking for leaks, double-frees, 1268 use-after-frees, and similar issues. 1269 * New warnings: 1270 + [28]-Wmismatched-dealloc, enabled by default, warns about 1271 calls to deallocation functions with pointers returned from 1272 mismatched allocation functions. 1273 + [29]-Wsizeof-array-div, enabled by -Wall, warns about 1274 divisions of two sizeof operators when the first one is 1275 applied to an array and the divisor does not equal the size of 1276 the array element. 1277 + [30]-Wstringop-overread, enabled by default, warns about calls 1278 to string functions reading past the end of the arrays passed 1279 to them as arguments. In prior GCC releases most instances of 1280 his warning are diagnosed by -Wstringop-overflow. 1281 + [31]-Wtsan, enabled by default, warns about unsupported 1282 features in ThreadSanitizer (currently 1283 std::atomic_thread_fence). 1284 * Enhancements to existing warnings: 1285 + [32]-Wfree-nonheap-object detects many more instances of calls 1286 to deallocation functions with pointers not returned from a 1287 dynamic memory allocation function. 1288 + [33]-Wmaybe-uninitialized diagnoses passing pointers or 1289 references to uninitialized memory to functions taking 1290 const-qualified arguments. 1291 + [34]-Wuninitialized detects reads from uninitialized 1292 dynamically allocated memory. 1293 * For ELF targets that support the GNU or FreeBSD OSABIs, the used 1294 attribute will now save the symbol declaration it is applied to 1295 from linker garbage collection. 1296 To support this behavior, used symbols that have not been placed in 1297 specific sections (e.g. with the section attribute, or the 1298 -f{function,data}-sections options) will be placed in new, unique 1299 sections. 1300 This functionality requires Binutils version 2.36 or later. 1301 1302 C 1303 1304 * Several new features from the upcoming C2X revision of the ISO C 1305 standard are supported with -std=c2x and -std=gnu2x. Some of these 1306 features are also supported as extensions when compiling for older 1307 language versions. In addition to the features listed, some 1308 features previously supported as extensions and now added to the C 1309 standard are enabled by default in C2X mode and not diagnosed with 1310 -std=c2x -Wpedantic. 1311 + The BOOL_MAX and BOOL_WIDTH macros are provided in <limits.h>. 1312 + As in C++, function definitions no longer need to give names 1313 for unused function parameters. 1314 + The expansions of the true and false macros in <stdbool.h> 1315 have changed so that they have type bool. 1316 + The [[nodiscard]] standard attribute is now supported. 1317 + The __has_c_attribute preprocessor operator is now supported. 1318 + Macros INFINITY, NAN, FLT_SNAN, DBL_SNAN, LDBL_SNAN, 1319 DEC_INFINITY, DEC_NAN, and corresponding signaling NaN macros 1320 for _FloatN, _FloatNx and _DecimalN types, are provided in 1321 <float.h>. There are also corresponding built-in functions 1322 __builtin_nansdN for decimal signaling NaNs. 1323 + Macros FLT_IS_IEC_60559, DBL_IS_IEC_60559 and 1324 LDBL_IS_IEC_60559 are provided in <float.h>. 1325 + The feature test macro __STDC_WANT_IEC_60559_EXT__ is 1326 supported by <float.h>. 1327 + Labels may appear before declarations and at the end of a 1328 compound statement. 1329 * New warnings: 1330 + [35]-Warray-parameter, enabled by -Wall, warns about 1331 redeclarations of functions with ordinary array arguments 1332 declared using inconsistent forms. The warning also enables 1333 the detection of the likely out of bounds accesses in calls to 1334 such functions with smaller arrays. 1335 + [36]-Wvla-parameter, enabled by -Wall, warns redeclarations of 1336 functions with variable length array arguments declared using 1337 inconsistent forms or with mismatched bounds. The warning also 1338 enables the detection of the likely out of bounds accesses in 1339 calls to such functions with smaller arrays. 1340 1341 C++ 1342 1343 * The default mode has been changed to -std=gnu++17. 1344 * Several C++20 features have been implemented: 1345 + the compiler now supports consteval virtual functions 1346 + P2082R1, Fixing CTAD for aggregates 1347 + P0593R6, Pseudo-destructors end object lifetimes 1348 + P1907R1, Inconsistencies with non-type template parameters 1349 (complete implementation) 1350 + P1975R0, Fixing the wording of parenthesized 1351 aggregate-initialization 1352 + P1009R2, Array size deduction in new-expressions 1353 + P1099R5, using enum 1354 + Modules, Requires -fmodules-ts and some aspects are 1355 incomplete. Refer to [37]C++ 20 Status 1356 * The C++ front end has experimental support for some of the upcoming 1357 C++23 draft features with the -std=c++23, -std=gnu++23, -std=c++2b 1358 or -std=gnu++2b flags, including 1359 + P0330R8, Literal Suffix for (signed) size_t. 1360 For a full list of new features, see [38]the C++ status page. 1361 * Several C++ Defect Reports have been resolved, e.g.: 1362 + DR 625, Use of auto as a template-argument 1363 + DR 1512, Pointer comparison vs qualification conversions 1364 + DR 1722, Should lambda to function pointer conversion function 1365 be noexcept? 1366 + DR 1914, Duplicate standard attributes 1367 + DR 2032, Default template-arguments of variable templates 1368 + DR 2289, Uniqueness of decomposition declaration names 1369 + DR 2237, Can a template-id name a constructor? 1370 + DR 2303, Partial ordering and recursive variadic inheritance 1371 + DR 2369, Ordering between constraints and substitution 1372 + DR 2450, braced-init-list as a template-argument 1373 * G++ now performs better access checking in templates ([39]PR41437). 1374 * reinterpret_casts in constexpr evaluation are now checked more 1375 completely ([40]PR95307). 1376 * The diagnostic for static_assert has been improved: the compiler 1377 now shows the expression including its template arguments (if there 1378 were any), and can point to the failing clause if the condition 1379 comprised of any logical AND operators ([41]PR97518). 1380 * New warnings: 1381 + [42]-Wctad-maybe-unsupported, disabled by default, warns about 1382 performing class template argument deduction on a type with no 1383 deduction guides. 1384 + [43]-Wrange-loop-construct, enabled by -Wall, warns when a 1385 range-based for-loop is creating unnecessary and expensive 1386 copies. 1387 + [44]-Wdeprecated-enum-enum-conversion, enabled by default in 1388 C++20, warns about deprecated arithmetic conversions on 1389 operands of enumeration types, as outlined in 1390 [depr.arith.conv.enum]. 1391 + [45]-Wdeprecated-enum-float-conversion, enabled by default in 1392 C++20, warns about deprecated arithmetic conversions on 1393 operands where one is of enumeration type and the other is of 1394 a floating-point type, as outlined in [depr.arith.conv.enum]. 1395 + [46]-Wmismatched-new-delete, enabled by -Wall, warns about 1396 calls to C++ operator delete with pointers returned from 1397 mismatched forms of operator new or from other mismatched 1398 allocation functions. 1399 + [47]-Wvexing-parse, enabled by default, warns about the most 1400 vexing parse rule: the cases when a declaration looks like a 1401 variable definition, but the C++ language requires it to be 1402 interpreted as a function declaration. 1403 * Enhancements to existing warnings: 1404 + [48]-Wnonnull considers the implicit this argument of every 1405 C++ nonstatic member function to have been implicitly declared 1406 with attribute nonnull and triggers warnings for calls where 1407 the pointer is null. 1408 1409 Runtime Library (libstdc++) 1410 1411 * Improved C++17 support, including: 1412 + std::from_chars and std::to_chars for floating-point types. 1413 * Improved experimental C++20 support, including: 1414 + Calendar additions to <chrono>. Thanks to Cassio Neri for 1415 optimizations. 1416 + std::bit_cast 1417 + std::source_location 1418 + Atomic wait and notify operations. 1419 + <barrier>, <latch>, and <semaphore> 1420 + <syncstream> 1421 + Efficient access to basic_stringbuf's buffer. 1422 + Heterogeneous lookup in unordered containers. 1423 * Experimental C++23 support, including: 1424 + contains member functions for strings, thanks to Paul Fee. 1425 + std::to_underlying, std::is_scoped_enum 1426 * Experimental support for Data-Parallel Types (simd) from the 1427 Parallelism 2 TS, thanks to Matthias Kretz. 1428 * Faster std::uniform_int_distribution, thanks to Daniel Lemire. 1429 1430 D 1431 1432 * New features: 1433 + A new bottom type typeof(*null) has been added to represent 1434 run-time errors and non-terminating functions. This also 1435 introduces a new standard alias for the type named noreturn, 1436 and is implicitly imported into every module. 1437 + Printf-like and scanf-like functions are now detected by 1438 prefixing them with pragma(printf) for printf-like functions 1439 or pragma(scanf) for scanf-like functions. 1440 + The __traits() expression now supports the extensions 1441 isDeprecated, isDisabled, isFuture, isModule, isPackage, 1442 child, isReturnOnStack, isZeroInit, getTargetInfo, 1443 getLocation, hasPostblit, isCopyable, getVisibility, and 1444 totype. 1445 + An expression-based contract syntax has been added to the 1446 language. 1447 + Function literals can now return a value by reference with the 1448 ref keyword. 1449 + A new syntax is available to declare aliases to function types 1450 using the alias syntax based on the assignment operator. 1451 + New types __c_complex_float, __c_complex_double, 1452 __c_complex_real, and __c_wchar_t have been added for 1453 interfacing with C and C++ code, and are available from the 1454 core.stdc.config module. 1455 + User-defined attributes can now be used to annotate enum 1456 members, alias declarations, and function parameters. 1457 + Templates alias parameters can now be instantiated with basic 1458 types such as int or void function(). 1459 + The mixin construct can now be used as types in the form 1460 mixin(string) var. 1461 + The mixin construct can now take an argument list, same as 1462 pragma(msg). 1463 * New intrinsics: 1464 + Bitwise rotate intrinsics core.bitop.rol and core.bitop.ror 1465 have been added. 1466 + Byte swap intrinsic core.bitop.byteswap for swapping bytes in 1467 a 2-byte ushort has been added. 1468 + Math intrinsics available from core.math now have overloads 1469 for float and double types. 1470 + Volatile intrinsics core.volatile.volatileLoad and 1471 core.volatile.volatileStore have been moved from the 1472 core.bitop module. 1473 * New attributes: 1474 + The following GCC attributes are now recognized and available 1475 from the gcc.attributes module with short-hand aliases for 1476 convenience: 1477 o @attribute("alloc_size", arguments) or 1478 @alloc_size(arguments). 1479 o @attribute("always_inline") or @always_inline. 1480 o @attribute("used") or @used. 1481 o @attribute("optimize", arguments) or 1482 @optimize(arguments). 1483 o @attribute("cold") or @cold. 1484 o @attribute("noplt") or @noplt. 1485 o @attribute("target_clones", arguments) or 1486 @target_clones(arguments). 1487 o @attribute("no_icf") or @no_icf. 1488 o @attribute("noipa") or @noipa. 1489 o @attribute("symver", arguments) or @symver(arguments). 1490 + New aliases have been added to gcc.attributes for 1491 compatibility with ldc.attributes. 1492 o The @allocSize(arguments) attribute is the same as 1493 @alloc_size(arguments), but uses a 0-based index for 1494 function arguments. 1495 o The @assumeUsed attribute is an alias for 1496 @attribute("used"). 1497 o The @fastmath attribute is an alias for 1498 @optimize("Ofast"). 1499 o The @naked attribute is an alias for @attribute("naked"). 1500 This attribute may not be available on all targets. 1501 o The @restrict attribute has been added to specify that a 1502 function parameter is to be restrict-qualified in the C99 1503 sense of the term. 1504 o The @optStrategy(strategy) attribute is an alias for 1505 @optimize("O0") when the strategy is "none", otherwise 1506 @optimize("Os") for the "optsize" and "minsize" 1507 strategies. 1508 o The @polly attribute is an alias for 1509 @optimize("loop-parallelize-all"). 1510 o The @section(name) attribute is an alias for 1511 @attribute("section", name). 1512 o The @target(arguments) attribute is an alias for 1513 attribute("target", arguments). 1514 o The @weak attribute is an alias for @attribute("weak"). 1515 * New language options: 1516 + -fweak-templates, added to control whether declarations that 1517 can be defined in multiple objects should be emitted as weak 1518 symbols. The default is to emit all symbols with extern 1519 linkage as weak, unless the target lacks support for weak 1520 symbols. 1521 + -Wdeprecated, this option is now enabled by default. 1522 + -Wextra, this option now turns on all warnings that are not 1523 part of the core D language front-end - -Waddress, 1524 -Wcast-result, -Wunknown-pragmas. 1525 + -Wvarargs, added to turn on warnings about questionable usage 1526 of the va_start intrinsic. 1527 * Deprecated and removed features: 1528 + Compiler-recognized attributes are now made available from the 1529 gcc.attributes module, the former module gcc.attribute has 1530 been deprecated and will be removed in a future release. 1531 + The @attribute("alias") attribute has been removed, as it had 1532 been superseded by pragma(mangle). 1533 + The @attribute("forceinline") attribute has been removed and 1534 renamed to @always_inline. 1535 + __vector types that are not supported in hardware are now 1536 rejected at compile-time. Previously all vector types were 1537 accepted by the compiler and emulated when target support was 1538 absent. 1539 + The extern(Pascal) linkage attribute has been removed. 1540 + The deprecation phase for -ftransition=import and 1541 -ftransition=checkimports is finished. These switches no 1542 longer have an effect and are now removed. Symbols that are 1543 not visible in a particular scope will no longer be found by 1544 the compiler. 1545 + It is now an error to use private variables selectively 1546 imported from other modules. Due to a bug, some imported 1547 private members were visible from other modules, violating the 1548 specification. 1549 + The -fweak compiler switch has been removed, as it existed 1550 only for testing. 1551 1552 Fortran 1553 1554 * Added DEPRECATED to !GCC$'s attributes directive. 1555 1556 Go 1557 1558 * GCC 11 provides a complete implementation of the Go 1.16.3 user 1559 packages. 1560 1561 libgccjit 1562 1563 * libgccjit was marked as merely "Alpha" quality when [49]originally 1564 added in GCC 5. Given that we have maintained [50]API and ABI 1565 compatibility since then and it is in use by various projects, we 1566 have removed that caveat. 1567 * libgccjit can now be built for MinGW 1568 * The libgccjit API gained 10 new entry points: 1569 + [51]gcc_jit_global_set_initializer 1570 + 9 entrypoints for [52]directly embedding asm statements into a 1571 compile, analogous to inline asm in the C front end 1572 1573 New Targets and Target Specific Improvements 1574 1575 AArch64 & arm 1576 1577 * A number of new CPUs are supported through arguments to the -mcpu 1578 and -mtune options in both the arm and aarch64 backends (GCC 1579 identifiers in parentheses): 1580 + Arm Cortex-A78 (cortex-a78). 1581 + Arm Cortex-A78AE (cortex-a78ae). 1582 + Arm Cortex-A78C (cortex-a78c). 1583 + Arm Cortex-X1 (cortex-x1). 1584 + Arm Neoverse V1 (neoverse-v1). 1585 + Arm Neoverse N2 (neoverse-n2). 1586 * GCC can now auto-vectorize operations performing addition, 1587 subtraction, multiplication and the accumulate/subtract variants on 1588 complex numbers, taking advantage of the Advanced SIMD instructions 1589 in the Armv8.3-a (AArch64/AArch32), SVE (AArch64), SVE2 (AArch64) 1590 and MVE (AArch32 M-profile) instruction sets. 1591 1592 AArch64 1593 1594 * In addition to the above, the following AArch64-only CPUs are now 1595 supported: 1596 + Fujitsu A64FX (a64fx). 1597 + Arm Cortex-R82 (cortex-r82). 1598 * The AArch64 Armv8-R architecture is now supported through the 1599 -march=armv8-r option. 1600 * Mitigation against the [53]Straight-line Speculation vulnerability 1601 is supported with the -mharden-sls= option. Please refer to the 1602 documentation for usage instructions. 1603 * The availability of Advanced SIMD intrinsics available through the 1604 arm_neon.h header is improved and GCC 11 supports the full set of 1605 intrinsics defined by ACLE Q3 2020. 1606 1607 AMD Radeon (GCN) 1608 1609 * Initial support for gfx908 GPUs has been added. 1610 1611 arm 1612 1613 * Initial auto-vectorization is now available when targeting the MVE 1614 instruction set. 1615 * GCC can now make use of the Low Overhead Branch instruction in 1616 Armv8.1-M to optimize loop counters and checks. 1617 * The -mcpu=cortex-m55 option now supports the extensions +nomve and 1618 +nomve.fp to control generation of MVE and MVE floating-point 1619 instructions. 1620 1621 IA-32/x86-64 1622 1623 * New ISA extension support for Intel TSXLDTRK was added to GCC. 1624 TSXLDTRK intrinsics are available via the -mtsxldtrk compiler 1625 switch. 1626 * New ISA extension support for Intel SERIALIZE was added to GCC. 1627 SERIALIZE intrinsics are available via the -mserialize compiler 1628 switch. 1629 * New ISA extension support for Intel HRESET was added to GCC. HRESET 1630 intrinsics are available via the -mhreset compiler switch. 1631 * New ISA extension support for Intel UINTR was added to GCC. UINTR 1632 intrinsics are available via the -muintr compiler switch. 1633 * New ISA extension support for Intel KEYLOCKER was added to GCC. 1634 KEYLOCKER intrinsics are available via the -mkeylocker compiler 1635 switch. 1636 * New ISA extension support for Intel AMX-TILE, AMX-INT8, AMX-BF16 1637 was added to GCC. AMX-TILE, AMX-INT8, AMX-BF16 intrinsics are 1638 available via the -mamx-tile, -mamx-int8, -mamx-bf16 compiler 1639 switches. 1640 * New ISA extension support for Intel AVX-VNNI was added to GCC. 1641 AVX-VNNI intrinsics are available via the -mavxvnni compiler 1642 switch. 1643 * GCC now supports the Intel CPU named Sapphire Rapids through 1644 -march=sapphirerapids. The switch enables the MOVDIRI, MOVDIR64B, 1645 AVX512VP2INTERSECT, ENQCMD, CLDEMOTE, SERIALIZE, PTWRITE, WAITPKG, 1646 TSXLDTRK, AMT-TILE, AMX-INT8, AMX-BF16, and AVX-VNNI ISA 1647 extensions. 1648 * GCC now supports the Intel CPU named Alderlake through 1649 -march=alderlake. The switch enables the CLDEMOTE, PTWRITE, 1650 WAITPKG, SERIALIZE, KEYLOCKER, AVX-VNNI, and HRESET ISA extensions. 1651 * GCC now supports the Intel CPU named Rocketlake through 1652 -march=rocketlake. Rocket Lake is based on Icelake client and minus 1653 SGX. 1654 * GCC now supports AMD CPUs based on the znver3 core via 1655 -march=znver3. 1656 * GCC now supports micro-architecture levels defined in the x86-64 1657 psABI via -march=x86-64-v2, -march=x86-64-v3 and -march=x86-64-v4. 1658 1659 Nios II 1660 1661 * The options -mcustom-insn=N no longer produce compiler warnings if 1662 the custom instruction is not generated due to missing optimization 1663 options such as -fno-math-errno, -ffinite-math-only, or 1664 -funsafe-math-optimizations. These warnings were not consistently 1665 emitted for all custom instructions. 1666 * The -mcustom-fpu-cfg=fph2 option has been added to enable the 1667 custom instructions supported by the Nios II Floating Point 1668 Hardware 2 Component. 1669 1670 NVPTX 1671 1672 * The -misa default has changed from sm_30 to sm_35. 1673 * The -m32 compiler switch has been removed. 1674 * The -msoft-stack-reserve-local format has been fixed. Previously, 1675 it accepted -msoft-stack-reserve-local<n>. It now accepts 1676 -msoft-stack-reserve-local=<n>. 1677 1678 S/390, System z, IBM Z Systems 1679 1680 * The behavior when compiling with -fexcess-precision=standard (e.g., 1681 implied by -std=c99) on s390(x) targets can now be controlled at 1682 configure time with the flag --enable-s390-excess-float-precision. 1683 When enabled, GCC will maintain previous behavior and evaluate 1684 float expressions in double precision, which aligns with the 1685 definition of float_t as double. With the flag disabled, GCC will 1686 always evaluate float expressions in single precision. In native 1687 builds and cross compiles that have target libc headers, GCC will 1688 by default match the definition of float_t in the installed glibc. 1689 1690 RISC-V 1691 1692 * Support address sanitizer for RISC-V. 1693 * Support big-endian for RISC-V, thanks to Marcus Comstedt. 1694 * Implement new style of architecture extension test macros: each 1695 architecture extension has a corresponding feature test macro, 1696 which can be used to test its existence and version information. 1697 * Legacy architecture extension test macros like __riscv_atomic are 1698 deprecated, but will still be supported for at least 2 release 1699 cycles. 1700 * Support IFUNC for riscv*-*-linux*. 1701 * Add new option -misa-spec=* to control ISA spec version. This 1702 controls the default version of each extensions. It defaults to 1703 2.2. 1704 * Introduce the --with-multilib-generator configure time option. This 1705 allows for flexible config multi-lib settings. Its syntax is the 1706 same as RISC-V's multilib-generator. 1707 * Extend the sytax for multilib-generator, support expansion operator 1708 * to reduce the complexity of complicated multi-lib re-use rules. 1709 * Support -mcpu=* option aligned with RISC-V clang/LLVM. It sets the 1710 pipeline model and architecture extensions, like -mtune=* plus 1711 -march=*. 1712 * Support for TLS stack protector canary access, thanks to Cooper Qu. 1713 * Support __builtin_thread_pointer for RISC-V. 1714 * Introduce shorten_memrefs optimization, which reduces the code size 1715 for memory access, thanks to Craig Blackmore. 1716 1717 Operating Systems 1718 1719 AIX 1720 1721 * GCC for AIX can be built as a 64 bit application and the runtime is 1722 built as FAT libraries containing both 32 bit and 64 bit objects. 1723 * Support AIX Vector Extended ABI with -mabi=vec-extabi. 1724 * Thread-Local uninitiated data placed in local common section. 1725 * Use thread-safe access in ctype. 1726 * Link with libc128.a when long-double-128 enabled. 1727 1728 Improvements to Static Analyzer 1729 1730 * The implementation of how program state is tracked within 1731 [54]-fanalyzer has been completely rewritten for GCC 11, fixing 1732 numerous bugs, and allowing for the analyzer to scale to larger C 1733 source files. 1734 * The analysis of allocations and deallocations has been generalized 1735 beyond malloc and free. 1736 + As preliminary work towards eventually supporting C++, the 1737 malloc/free checking will also check new/delete and 1738 new[]/delete[]. However, C++ is not yet properly supported by 1739 [55]-fanalyzer (for example, exception-handling is 1740 unimplemented). 1741 + As noted above, the existing [56]malloc attribute has been 1742 extended so that it can be used to identify 1743 allocator/deallocator API pairs. The analyzer will use these 1744 attributes when checking for leaks, double-frees, 1745 use-after-frees, and similar issues. 1746 + A new [57]-Wanalyzer-mismatching-deallocation warning has been 1747 added, covering such mismatches as using scalar delete rather 1748 vector delete[]. 1749 * The analyzer has gained warnings 1750 [58]-Wanalyzer-shift-count-negative, 1751 [59]-Wanalyzer-shift-count-overflow, [60]-Wanalyzer-write-to-const, 1752 and [61]-Wanalyzer-write-to-string-literal, all enabled by default 1753 when [62]-fanalyzer is enabled. 1754 * The analyzer can now be extended by GCC plugins, allowing for 1755 domain-specific path-sensitive warnings. An example of using a 1756 [63]GCC plugin to check for misuses of CPython's global interpreter 1757 lock can be seen in the test suite 1758 * The analyzer has gained new debugging options 1759 [64]-fdump-analyzer-json and [65]-fno-analyzer-feasibility. 1760 1761 Other significant improvements 1762 1763 * GCC has gained a new environment variable 1764 [66]GCC_EXTRA_DIAGNOSTIC_OUTPUT which can be used by IDEs to 1765 request machine-readable fix-it hints without needing to adjust 1766 build flags. 1767 1768 GCC 11.1 1769 1770 This is the [67]list of problem reports (PRs) from GCC's bug tracking 1771 system that are known to be fixed in the 11.1 release. This list might 1772 not be complete (that is, it is possible that some PRs that have been 1773 fixed are not listed here). 1774 1775 GCC 11.2 1776 1777 This is the [68]list of problem reports (PRs) from GCC's bug tracking 1778 system that are known to be fixed in the 11.2 release. This list might 1779 not be complete (that is, it is possible that some PRs that have been 1780 fixed are not listed here). 1781 1782 GCC 11.3 1783 1784 This is the [69]list of problem reports (PRs) from GCC's bug tracking 1785 system that are known to be fixed in the 11.3 release. This list might 1786 not be complete (that is, it is possible that some PRs that have been 1787 fixed are not listed here). 1788 1789 Target Specific Changes 1790 1791 x86-64 1792 1793 * The x86-64 ABI of passing and returning structure with a 64-bit 1794 single precision vector changed in GCC 11.1 when 3DNOW is disabled. 1795 Disabling 3DNOW no longer changes how they are passed nor returned. 1796 This ABI change is now diagnosed with -Wpsabi. 1797 * Mitigation against straight line speculation (SLS) for function 1798 return and indirect jump is supported via 1799 -mharden-sls=[none|all|return|indirect-jmp]. 1800 * Add CS prefix to call and jmp to indirect thunk with branch target 1801 in r8-r15 registers via -mindirect-branch-cs-prefix. 1802 1803 1804 For questions related to the use of GCC, please consult these web 1805 pages and the [70]GCC manuals. If that fails, the 1806 [71]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1807 web pages and the development of GCC are welcome on our developer 1808 list at [72]gcc (a] gcc.gnu.org. All of [73]our lists have public 1809 archives. 1810 1811 Copyright (C) [74]Free Software Foundation, Inc. Verbatim copying and 1812 distribution of this entire article is permitted in any medium, 1813 provided this notice is preserved. 1814 1815 These pages are [75]maintained by the GCC team. Last modified 1816 2023-02-02. 1817 1818 References 1819 1820 1. http://gcc.gnu.org/gcc-11/porting_to.html 1821 2. http://gcc.gnu.org/onlinedocs/index.html#current 1822 3. https://wg21.link/p0522r0 1823 4. https://gcc.gnu.org/pipermail/gcc-patches/2020-May/546494.html 1824 5. https://github.com/google/sanitizers/wiki/ThreadSanitizerCppManual 1825 6. https://www.kernel.org/doc/html/latest/dev-tools/kcsan.html 1826 7. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-column-unit 1827 8. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-column-origin 1828 9. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 1829 10. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Preprocessor-Options.html#index-ftabstop 1830 11. https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html 1831 12. https://github.com/google/sanitizers/wiki/AddressSanitizer 1832 13. https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html 1833 14. https://dwarfstd.org/doc/DWARF5.pdf 1834 15. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Code-Gen-Options.html#index-fno-bit-tests 1835 16. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Optimize-Options.html#index-fipa-modref 1836 17. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Optimize-Options.html#index-fipa-ocf 1837 18. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Optimize-Options.html#index-fprofile-values 1838 19. https://www.openmp.org/specifications/ 1839 20. https://www.openacc.org/ 1840 21. https://gcc.gnu.org/wiki/OpenACC/Implementation%20Status#status-11 1841 22. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/libgomp/Enabling-OpenACC.html 1842 23. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Common-Function-Attributes.html#index-no_005fstack_005fprotector-function-attribute 1843 24. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Common-Function-Attributes.html#index-malloc-function-attribute 1844 25. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wmismatched-dealloc 1845 26. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-new-delete 1846 27. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wfree-nonheap-object 1847 28. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wmismatched-dealloc 1848 29. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wsizeof-array-div 1849 30. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wstringop-overread 1850 31. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wtsan 1851 32. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wfree-nonheap-object 1852 33. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wmaybe-uninitialized 1853 34. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wuninitialized 1854 35. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Warray-parameter 1855 36. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wvla-parameter 1856 37. http://gcc.gnu.org/projects/cxx-status.html#cxx20 1857 38. http://gcc.gnu.org/projects/cxx-status.html#cxx23 1858 39. https://gcc.gnu.org/PR41437 1859 40. https://gcc.gnu.org/PR95307 1860 41. https://gcc.gnu.org/PR97518 1861 42. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wctad-maybe-unsupported 1862 43. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wrange-loop-construct 1863 44. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wdeprecated-enum-enum-conversion 1864 45. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wdeprecated-enum-float-conversion 1865 46. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-new-delete 1866 47. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wvexing-parse 1867 48. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Warning-Options.html#index-Wnonnull 1868 49. http://gcc.gnu.org/gcc-5/changes.html#jit 1869 50. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/jit/topics/compatibility.html 1870 51. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/jit/topics/expressions.html#c.gcc_jit_global_set_initializer 1871 52. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/jit/topics/asm.html 1872 53. https://developer.arm.com/documentation/102587/0102/Straight-line-speculation-frequently-asked-questions 1873 54. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html 1874 55. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html 1875 56. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Common-Function-Attributes.html#index-malloc-function-attribute 1876 57. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-mismatching-deallocation 1877 58. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-shift-count-negative 1878 59. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-shift-count-overflow 1879 60. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-write-to-const 1880 61. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-Wanalyzer-write-to-string-literal 1881 62. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html 1882 63. https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=66dde7bc64b75d4a338266333c9c490b12d49825 1883 64. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-fdump-analyzer-json 1884 65. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Static-Analyzer-Options.html#index-fno-analyzer-feasibility 1885 66. https://gcc.gnu.org/onlinedocs/gcc-11.1.0/gcc/Environment-Variables.html#index-GCC_005fEXTRA_005fDIAGNOSTIC_005fOUTPUT 1886 67. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=11.0 1887 68. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=11.2 1888 69. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=11.3 1889 70. https://gcc.gnu.org/onlinedocs/ 1890 71. mailto:gcc-help (a] gcc.gnu.org 1891 72. mailto:gcc (a] gcc.gnu.org 1892 73. https://gcc.gnu.org/lists.html 1893 74. https://www.fsf.org/ 1894 75. https://gcc.gnu.org/about.html 1895 ====================================================================== 1896 http://gcc.gnu.org/gcc-10/index.html 1897 1898 GCC 10 Release Series 1899 1900 June 28, 2022 1901 1902 The [1]GNU project and the GCC developers are pleased to announce the 1903 release of GCC 10.4. 1904 1905 This release is a bug-fix release, containing fixes for regressions in 1906 GCC 10.3 relative to previous releases of GCC. 1907 1908 Release History 1909 1910 GCC 10.4 1911 June 28, 2022 ([2]changes, [3]documentation) 1912 1913 GCC 10.3 1914 April 8, 2021 ([4]changes, [5]documentation) 1915 1916 GCC 10.2 1917 July 23, 2020 ([6]changes, [7]documentation) 1918 1919 GCC 10.1 1920 May 7, 2020 ([8]changes, [9]documentation) 1921 1922 References and Acknowledgements 1923 1924 GCC used to stand for the GNU C Compiler, but since the compiler 1925 supports several other languages aside from C, it now stands for the 1926 GNU Compiler Collection. 1927 1928 A list of [10]successful builds is updated as new information becomes 1929 available. 1930 1931 The GCC developers would like to thank the numerous people that have 1932 contributed new features, improvements, bug fixes, and other changes as 1933 well as test results to GCC. This [11]amazing group of volunteers is 1934 what makes GCC successful. 1935 1936 For additional information about GCC please refer to the [12]GCC 1937 project web site or contact the [13]GCC development mailing list. 1938 1939 To obtain GCC please use [14]our mirror sites or [15]our version 1940 control system. 1941 1942 1943 For questions related to the use of GCC, please consult these web 1944 pages and the [16]GCC manuals. If that fails, the 1945 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1946 web pages and the development of GCC are welcome on our developer 1947 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 1948 archives. 1949 1950 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 1951 distribution of this entire article is permitted in any medium, 1952 provided this notice is preserved. 1953 1954 These pages are [21]maintained by the GCC team. Last modified 1955 2022-10-26. 1956 1957 References 1958 1959 1. http://www.gnu.org/ 1960 2. http://gcc.gnu.org/gcc-10/changes.html 1961 3. http://gcc.gnu.org/onlinedocs/10.4.0/ 1962 4. http://gcc.gnu.org/gcc-10/changes.html 1963 5. http://gcc.gnu.org/onlinedocs/10.3.0/ 1964 6. http://gcc.gnu.org/gcc-10/changes.html 1965 7. http://gcc.gnu.org/onlinedocs/10.2.0/ 1966 8. http://gcc.gnu.org/gcc-10/changes.html 1967 9. http://gcc.gnu.org/onlinedocs/10.1.0/ 1968 10. http://gcc.gnu.org/gcc-10/buildstat.html 1969 11. http://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Contributors.html 1970 12. http://gcc.gnu.org/index.html 1971 13. mailto:gcc (a] gcc.gnu.org 1972 14. http://gcc.gnu.org/mirrors.html 1973 15. http://gcc.gnu.org/git.html 1974 16. https://gcc.gnu.org/onlinedocs/ 1975 17. mailto:gcc-help (a] gcc.gnu.org 1976 18. mailto:gcc (a] gcc.gnu.org 1977 19. https://gcc.gnu.org/lists.html 1978 20. https://www.fsf.org/ 1979 21. https://gcc.gnu.org/about.html 1980 ====================================================================== 1981 http://gcc.gnu.org/gcc-10/changes.html 1982 1983 GCC 10 Release Series 1984 Changes, New Features, and Fixes 1985 1986 This page is a "brief" summary of some of the huge number of 1987 improvements in GCC 10. You may also want to check out our [1]Porting 1988 to GCC 10 page and the [2]full GCC documentation. 1989 1990 Caveats 1991 1992 * An ABI incompatibility between C++14 and C++17 has been fixed. On 1993 some targets a class with a zero-sized subobject would be passed 1994 incorrectly when compiled as C++17 or C++20. See the [3]C++ notes 1995 below for more details. 1996 * The deprecated Profile Mode and array_allocator extensions have 1997 been removed from libstdc++. 1998 * The non-standard std::__is_nullptr_t type trait is deprecated and 1999 will be removed from libstdc++ in a future release. The standard 2000 trait std::is_null_pointer should be instead. 2001 * The minimum version of the [4]MPFR library required for building 2002 GCC has been increased to version 3.1.0 (released 2011-10-03). 2003 * The automatic template instantiation at link time (-frepo) has been 2004 removed. 2005 * The --param allow-store-data-races internal parameter has been 2006 removed in favor of a new official option -fallow-store-data-races. 2007 While default behavior is unchanged and the new option allows to 2008 correctly maintain a per compilation unit setting across link-time 2009 optimization, alteration of the default via --param 2010 allow-store-data-races will now be diagnosed and build systems have 2011 to be adjusted accordingly. 2012 * Offloading to Heterogeneous System Architecture Intermediate 2013 Language (HSAIL) has been deprecated and will likely be removed in 2014 a future release. 2015 * The type of the std::iterator base class of 2016 std::istreambuf_iterator was changed in C++98 mode to be consistent 2017 with C++11 and later standards. See the [5]libstdc++ notes below 2018 for more details. 2019 2020 General Improvements 2021 2022 * New built-in functions: 2023 + The [6]__has_builtin built-in preprocessor operator can be 2024 used to query support for built-in functions provided by GCC 2025 and other compilers that support it. 2026 + __builtin_roundeven for the corresponding function from 2027 ISO/IEC TS 18661. 2028 * New command-line options: 2029 + [7]-fallocation-dce removes unneeded pairs of new and delete 2030 operators. 2031 + [8]-fprofile-partial-training can now be used to inform the 2032 compiler that code paths not covered by the training run 2033 should not be optimized for size. 2034 + [9]-fprofile-reproducible controls level of reproducibility of 2035 profile gathered by [10]-fprofile-generate. This makes it 2036 possible to rebuild program with same outcome which is useful, 2037 for example, for distribution packages. 2038 + [11]-fprofile-prefix-path can be used in combination with 2039 -fprofile-generate=profile_dir and -fprofile-use=profile_dir 2040 to inform GCC where the base directory of build source tree is 2041 in case it differs between instrumentation and optimized 2042 builds. 2043 + [12]-fanalyzer enables a new static analysis pass and 2044 associated warnings. This pass performs a time-consuming 2045 exploration of paths through the code in the hope of detecting 2046 various common errors, such as double-free bugs. This option 2047 should be regarded as experimental in this release. In 2048 particular, analysis of non-C code is unlikely to work. 2049 * Inter-procedural optimization improvements: 2050 + The inter-procedural scalar replacement of aggregates 2051 (IPA-SRA) pass was re-implemented to work at link-time and can 2052 now also remove computing and returning unused return values. 2053 + [13]-finline-functions is now enabled at -O2 and was retuned 2054 for better code size versus runtime performance trade-offs. 2055 Inliner heuristics was also significantly sped up to avoid 2056 negative impact to -flto -O2 compile times. 2057 + Inliner heuristics and function cloning can now use 2058 value-range information to predict effectivity of individual 2059 transformations. 2060 + During link-time optimization the C++ One Definition Rule is 2061 used to increase precision of type based alias analysis. 2062 * Link-time optimization improvements: 2063 + A new binary [14]lto-dump has been added. It dumps various 2064 information about LTO bytecode object files. 2065 + The parallel phase of the LTO can automatically detect a 2066 running make's jobserver or fall back to number of available 2067 cores. 2068 + The LTO bytecode can be compressed with the [15]zstd 2069 algorithm. The configure script automatically detects zstd 2070 support. 2071 + Most --param values can now be specified at translation unit 2072 granularity. This includes all parameters controlling the 2073 inliner and other inter-procedural optimizations. Unlike 2074 earlier releases, GCC 10 will ignore parameters controlling 2075 optimizations specified at link-time and apply parameters 2076 specified at compile-time in the same manner as done for 2077 optimization flags. 2078 * Profile driven optimization improvements: 2079 + Profile maintenance during compilation and hot/cold code 2080 partitioning have been improved. 2081 + Using [16]-fprofile-values, an instrumented binary can track 2082 multiple values (up to 4) for e.g. indirect calls and provide 2083 more precise profile information. 2084 2085 New Languages and Language-Specific Improvements 2086 2087 * Version 2.6 of the [17]OpenACC specification is now supported by 2088 the C, C++ and Fortran compilers. See the [18]implementation status 2089 section on the OpenACC wiki page and the [19]run-time library 2090 documentation for further information. 2091 * GCC 10 adds a number of newly implemented [20]OpenMP 5.0 features 2092 such as conditional lastprivate clause, scan and loop directives, 2093 order(concurrent) and use_device_addr clauses support, if clause on 2094 simd construct, and partial support for the declare variant 2095 directive, getting closer to full support of the OpenMP 5.0 2096 standard. 2097 * OpenMP and OpenACC now support [21]offloading to AMD Radeon (GCN) 2098 GPUs; supported are the third-generation Fiji (fiji) and the 2099 fifth-generation VEGA 10/VEGA 20 (gfx900 or gfx906). 2100 2101 C family 2102 2103 * New attributes: 2104 + The access function and type attribute has been added to 2105 describe how a function accesses objects passed to it by 2106 pointer or reference, and to associate such arguments with 2107 integer arguments denoting the objects' sizes. The attribute 2108 is used to enable the detection of invalid accesses by 2109 user-defined functions, such as those diagnosed by 2110 -Wstringop-overflow. 2111 + The symver attribute can be used to bind symbols to specific 2112 version nodes on ELF platforms. This is preferred to using 2113 inline assembly with GNU as symver directive because the 2114 latter is not compatible with link-time optimizations. 2115 * New warnings: 2116 + [22]-Wstring-compare, enabled by -Wextra, warns about equality 2117 and inequality expressions between zero and the result of a 2118 call to either strcmp and strncmp that evaluate to a constant 2119 as a result of the length of one argument being greater than 2120 the size of the array pointed to by the other. 2121 + [23]-Wzero-length-bounds, enabled by -Warray-bounds, warns 2122 about accesses to elements of zero-length arrays that might 2123 overlap other members of the same object. 2124 * Enhancements to existing warnings: 2125 + [24]-Warray-bounds detects more out-of-bounds accesses to 2126 member arrays as well as accesses to elements of zero-length 2127 arrays. 2128 + [25]-Wformat-overflow makes full use of string length 2129 information computed by the strlen optimization pass. 2130 + [26]-Wrestrict detects overlapping accesses to dynamically 2131 allocated objects. 2132 + [27]-Wreturn-local-addr diagnoses more instances of return 2133 statements returning addresses of automatic variables. 2134 + [28]-Wstringop-overflow detects more out-of-bounds stores to 2135 member arrays including zero-length arrays, dynamically 2136 allocated objects and variable length arrays, as well as more 2137 instances of reads of unterminated character arrays by string 2138 built-in functions. The warning also detects out-of-bounds 2139 accesses by calls to user-defined functions declared with the 2140 new attribute access. 2141 + [29]-Warith-conversion re-enables warnings from -Wconversion, 2142 -Wfloat-conversion, and -Wsign-conversion that are now off by 2143 default for an expression where the result of an arithmetic 2144 operation will not fit in the target type due to promotion, 2145 but the operands of the expression do fit in the target type. 2146 * Extended characters in identifiers may now be specified directly in 2147 the input encoding (UTF-8, by default), in addition to the UCN 2148 syntax (\uNNNN or \UNNNNNNNN) that is already supported: 2149 2150 static const int p = 3; 2151 int get_nave_pi() { 2152 return p; 2153 } 2154 2155 C 2156 2157 * Several new features from the upcoming C2X revision of the ISO C 2158 standard are supported with -std=c2x and -std=gnu2x. Some of these 2159 features are also supported as extensions when compiling for older 2160 language versions. In addition to the features listed, some 2161 features previously supported as extensions and now added to the C 2162 standard are enabled by default in C2X mode and not diagnosed with 2163 -std=c2x -Wpedantic. 2164 + The [[]] attribute syntax is supported, as in C++. Existing 2165 attributes can be used with this syntax in forms such as 2166 [[gnu::const]]. The standard attributes [[deprecated]], 2167 [[fallthrough]] and [[maybe_unused]] are supported. 2168 + UTF-8 character constants using the u8'' syntax are supported. 2169 + <float.h> defines macros FLT_NORM_MAX, DBL_NORM_MAX and 2170 LDBL_NORM_MAX. 2171 + When decimal floating-point arithmetic is supported, <float.h> 2172 defines macros DEC32_TRUE_MIN, DEC64_TRUE_MIN and 2173 DEC128_TRUE_MIN, in addition to the macros that were 2174 previously only defined if __STDC_WANT_DEC_FP__ was defined 2175 before including <float.h>. 2176 + In C2X mode, empty parentheses in a function definition give 2177 that function a type with a prototype for subsequent calls; 2178 other old-style function definitions are diagnosed by default 2179 in C2X mode. 2180 + The strftime format checking supports the %OB and %Ob formats. 2181 + In C2X mode, -fno-fp-int-builtin-inexact is enabled by 2182 default. 2183 * GCC now defaults to -fno-common. As a result, global variable 2184 accesses are more efficient on various targets. In C, global 2185 variables with multiple tentative definitions now result in linker 2186 errors. With -fcommon such definitions are silently merged during 2187 linking. 2188 2189 C++ 2190 2191 * Several C++20 features have been implemented: 2192 + Concepts, including P0734R0, P0857R0, P1084R2, P1141R2, 2193 P0848R3, P1616R1, P1452R2 2194 + P1668R1, Permitting Unevaluated inline-assembly in constexpr 2195 Functions 2196 + P1161R3, Deprecate a[b,c] 2197 + P0848R3, Conditionally Trivial Special Member Functions 2198 + P1091R3, Extending structured bindings 2199 + P1143R2, Adding the constinit keyword 2200 + P1152R4, Deprecating volatile 2201 + P0388R4, Permit conversions to arrays of unknown bound 2202 + P0784R7, constexpr new 2203 + P1301R4, [[nodiscard("with reason")]] 2204 + P1814R0, class template argument deduction for alias templates 2205 + P1816R0, class template argument deduction for aggregates 2206 + P0960R3, Parenthesized initialization of aggregates 2207 + P1331R2, Allow trivial default initialization in constexpr 2208 contexts 2209 + P1327R1, Allowing dynamic_cast and polymorphic typeid in 2210 constexpr contexts 2211 + P0912R5, Coroutines (requires -fcoroutines) 2212 * Several C++ Defect Reports have been resolved, e.g.: 2213 + DR 1560, lvalue-to-rvalue conversion in ?: 2214 + DR 1813, __is_standard_layout for a class with repeated bases 2215 + DR 2094, volatile scalars are trivially copyable, 2216 + DR 2096, constraints on literal unions 2217 + DR 2413, typename in conversion-function-ids 2218 + DR 2352, Similar types and reference binding 2219 + DR 1601, Promotion of enumeration with fixed underlying type 2220 + DR 330, Qualification conversions and pointers to arrays of 2221 pointers 2222 + DR 1307, Overload resolution based on size of array 2223 initializer-list 2224 + DR 1710, Missing template keyword in class-or-decltype 2225 * New warnings: 2226 + [30]-Wmismatched-tags, disabled by default, warns about 2227 declarations of structs, classes, and class templates and 2228 their specializations with a class-key that does not match 2229 either the definition or the first declaration if no 2230 definition is provided. The option is provided to ease 2231 portability to Windows-based compilers. 2232 + [31]-Wredundant-tags, disabled by default, warns about 2233 redundant class-key and enum-key in contexts where the key can 2234 be eliminated without causing an syntactic ambiguity. 2235 * G++ can now detect modifying constant objects in constexpr 2236 evaluation (which is undefined behavior). 2237 * G++ no longer emits bogus -Wsign-conversion warnings with explicit 2238 casts. 2239 * Narrowing is now detected in more contexts (e.g., case values). 2240 * Memory consumption of the compiler has been reduced in constexpr 2241 evaluation. 2242 * The noexcept-specifier is now properly treated as a complete-class 2243 context as per [class.mem]. 2244 * The attribute deprecated can now be used on namespaces too. 2245 * The ABI of passing and returning certain C++ classes by value 2246 changed on several targets in GCC 10, including [32]AArch64, 2247 [33]ARM, [34]PowerPC ELFv2, [35]S/390 and [36]Itanium. These 2248 changes affect classes with a zero-sized subobject (an empty base 2249 class, or data member with the [[no_unique_address]] attribute) 2250 where all other non-static data members have the same type (this is 2251 called a "homogeneous aggregate" in some ABI specifications, or if 2252 there is only one such member, a "single element"). In -std=c++17 2253 and -std=c++20 modes, classes with an empty base class were not 2254 considered to have a single element or to be a homogeneous 2255 aggregate, and so could be passed differently (in the wrong 2256 registers or at the wrong stack address). This could make code 2257 compiled with -std=c++17 and -std=c++14 ABI incompatible. This has 2258 been corrected and the empty bases are ignored in those ABI 2259 decisions, so functions compiled with -std=c++14 and -std=c++17 are 2260 now ABI compatible again. Example: struct empty {}; struct S : 2261 empty { float f; }; void f(S);. Similarly, in classes containing 2262 non-static data members with empty class types using the C++20 2263 [[no_unique_address]] attribute, those members weren't ignored in 2264 the ABI argument passing decisions as they should be. Both of these 2265 ABI changes are now diagnosed with -Wpsabi. 2266 2267 Runtime Library (libstdc++) 2268 2269 * Improved experimental C++2a support, including: 2270 + Library concepts in <concepts> and <iterator>. 2271 + Constrained algorithms in <ranges>, <algorithm>, and <memory> 2272 (thanks to Patrick Palka). 2273 + New algorithms shift_left and shift_right (thanks to Patrick 2274 Palka). 2275 + std::span (thanks to JeanHeyd Meneide). 2276 + Three-way comparisons in <compare> and throughout the library. 2277 + Constexpr support in <algorithm> and elsewhere (thanks to 2278 Edward Smith-Rowland). 2279 + <stop_token> and std::jthread (thanks to Thomas Rodgers). 2280 + std::atomic_ref and std::atomic<floating point>. 2281 + Integer comparison functions (cmp_equal, cmp_less etc.). 2282 + std::ssize, std::to_array. 2283 + std::construct_at, std::destroy, constexpr std::allocator. 2284 + Mathematical constants in <numbers>. 2285 * Support for RDSEED in std::random_device. 2286 * Reduced header dependencies, leading to faster compilation for some 2287 code. 2288 * The std::iterator base class of std::istreambuf_iterator was 2289 changed in C++98 mode to be consistent with C++11 and later 2290 standards. This is expected to have no noticeable effect except in 2291 the unlikely case of a class which has potentially overlapping 2292 subobjects of type std::istreambuf_iterator<C> and another iterator 2293 type with a std::iterator<input_iterator_tag, C, ...> base class. 2294 The layout of such a type might change when compiled as C++98. 2295 [37]Bug 92285 has more details and concrete examples. 2296 2297 D 2298 2299 * Support for static foreach has been implemented. 2300 * Aliases can now be created directly from any __traits that return 2301 symbols or tuples. Previously, an AliasSeq was necessary in order 2302 to alias their return. 2303 * It is now possible to detect the language ABI specified for a 2304 struct, class, or interface using __traits(getLinkage, ...). 2305 * Support for core.math.toPrec intrinsics has been added. These 2306 intrinsics guarantee the rounding to specific floating-point 2307 precisions at specified points in the code. 2308 * Support for pragma(inline) has been implemented. Previously the 2309 pragma was recognized, but had no effect on the compilation. 2310 * Optional parentheses in asm operands are deprecated and will be 2311 removed in a future release. 2312 * All content imported files are now included in the make dependency 2313 list when compiling with -M. 2314 * Compiler recognized attributes provided by the gcc.attribute module 2315 will now take effect when applied to function prototypes as well as 2316 when applied to full function declarations. 2317 * Added a --enable-libphobos-checking configure option to control 2318 whether run-time checks are compiled into the D runtime library. 2319 * Added a --with-libphobos-druntime-only configure option to indicate 2320 whether to build only the core D runtime library, or both the core 2321 and standard libraries into libphobos. 2322 2323 Fortran 2324 2325 * use_device_addr of version 5.0 of the [38]OpenMP specification is 2326 now supported. Note that otherwise OpenMP 4.5 is partially 2327 supported in the Fortran compiler; the largest missing item is 2328 structure element mapping. 2329 * The default buffer size for I/O using unformatted files has been 2330 increased to 1048576. The buffer size for can now be set at runtime 2331 via the environment variables GFORTRAN_FORMATTED_BUFFER_SIZE and 2332 GFORTRAN_UNFORMATTED_BUFFER_SIZE for formatted and unformatted 2333 files, respectively. 2334 * Mismatches between actual and dummy argument lists in a single file 2335 are now rejected with an error. Use the new option 2336 -fallow-argument-mismatch to turn these errors into warnings; this 2337 option is implied with -std=legacy. -Wargument-mismatch has been 2338 removed. 2339 * The handling of a BOZ literal constant has been reworked to provide 2340 better conformance to the Fortran 2008 and 2018 standards. In these 2341 Fortran standards, a BOZ literal constant is a typeless and 2342 kindless entity. As a part of the rework, documented and 2343 undocumented extensions to the Fortran standard now emit errors 2344 during compilation. Some of these extensions are permitted with the 2345 -fallow-invalid-boz option, which degrades the error to a warning 2346 and the code is compiled as with older gfortran. 2347 * At any optimization level except-Os, gfortran now uses inline 2348 packing for arguments instead of calling a library routine. If the 2349 source contains a large number of arguments that need to be 2350 repacked, code size or time for compilation can become excessive. 2351 If that is the case, -fno-inline-arg-packing can be used to disable 2352 inline argument packing. 2353 * Legacy extensions: 2354 + For formatted input/output, if the explicit widths after the 2355 data-edit descriptors I, F and G have been omitted, default 2356 widths are used. 2357 + A blank format item at the end of a format specification, i.e. 2358 nothing following the final comma, is allowed. Use the option 2359 -fdec-blank-format-item; this option is implied with -fdec. 2360 + The existing support for AUTOMATIC and STATIC attributes has 2361 been extended to allow variables with the AUTOMATIC attribute 2362 to be used in EQUIVALENCE statements. Use -fdec-static; this 2363 option is implied by -fdec. 2364 + Allow character literals in assignments and DATA statements 2365 for numeric (INTEGER, REAL, or COMPLEX) or LOGICAL variables. 2366 Use the option -fdec-char-conversions; this option is implied 2367 with -fdec. 2368 + DEC comparisons, i.e. allow Hollerith constants to be used in 2369 comparisons with INTEGER, REAL, COMPLEX and CHARACTER 2370 expressions. Use the option -fdec. 2371 * Character type names in errors and warnings now include len in 2372 addition to kind; * is used for assumed length. The kind is omitted 2373 if it is the default kind. Examples: CHARACTER(12), CHARACTER(6,4). 2374 * CO_BROADCAST now supports derived type variables including objects 2375 with allocatable components. In this case, the optional arguments 2376 STAT= and ERRMSG= are currently ignored. 2377 * The handling of module and submodule names has been reworked to 2378 allow the full 63-character length mandated by the standard. 2379 Previously symbol names were truncated if the combined length of 2380 module, submodule, and function name exceeded 126 characters. This 2381 change therefore breaks the ABI, but only for cases where this 126 2382 character limit was exceeded. 2383 2384 Go 2385 2386 * GCC 10 provides a complete implementation of the Go 1.14.6 user 2387 packages. 2388 2389 libgccjit 2390 2391 * The libgccjit API gained four new entry points: 2392 + [39]gcc_jit_version_major, [40]gcc_jit_version_minor, and 2393 [41]gcc_jit_version_patchlevel for programmatically checking 2394 the libgccjit version from client code, and 2395 + [42]gcc_jit_context_new_bitfield 2396 2397 New Targets and Target Specific Improvements 2398 2399 AArch64 & arm 2400 2401 * The AArch64 and arm ports now support condition flag output 2402 constraints in inline assembly, as indicated by the 2403 __GCC_ASM_FLAG_OUTPUTS__. On arm this feature is only available for 2404 A32 and T32 targets. Please refer to the documentation for more 2405 details. 2406 2407 AArch64 2408 2409 * There have been several improvements related to the Scalable Vector 2410 Extension (SVE): 2411 + The SVE ACLE types and intrinsics are now supported. They can 2412 be accessed using the header file arm_sve.h. 2413 + It is now possible to create fixed-length SVE types using the 2414 arm_sve_vector_bits attribute. For example: 2415 #if __ARM_FEATURE_SVE_BITS==512 2416 typedef svint32_t vec512 __attribute__((arm_sve_vector_bits(512))); 2417 typedef svbool_t pred512 __attribute__((arm_sve_vector_bits(512))); 2418 #endif 2419 + -mlow-precision-div, -mlow-precision-sqrt and 2420 -mlow-precision-recip-sqrt now work for SVE. 2421 + -msve-vector-bits=128 now generates vector-length-specific 2422 code for little-endian targets. It continues to generate 2423 vector-length-agnostic code for big-endian targets, just as 2424 previous releases did for all targets. 2425 + The vectorizer is now able to use extending loads and 2426 truncating stores, including gather loads and scatter stores. 2427 + The vectorizer now compares the cost of vectorizing with SVE 2428 and vectorizing with Advanced SIMD and tries to pick the best 2429 one. Previously it would always use SVE if possible. 2430 + If a vector loop uses Advanced SIMD rather than SVE, the 2431 vectorizer now considers using SVE to vectorize the left-over 2432 elements (the "scalar tail" or "epilog"). 2433 + Besides these specific points, there have been many general 2434 improvements to the way that the vectorizer uses SVE. 2435 * The -mbranch-protection=pac-ret option now accepts the optional 2436 argument +b-key extension to perform return address signing with 2437 the B-key instead of the A-key. 2438 * The option -moutline-atomics has been added to aid deployment of 2439 the Large System Extensions (LSE) on GNU/Linux systems built with a 2440 baseline architecture targeting Armv8-A. When the option is 2441 specified code is emitted to detect the presence of LSE 2442 instructions at runtime and use them for standard atomic 2443 operations. For more information please refer to the documentation. 2444 * The Transactional Memory Extension is now supported through ACLE 2445 intrinsics. It can be enabled through the +tme option extension 2446 (for example, -march=armv8.5-a+tme). 2447 * A number of features from Armv8.5-A are now supported through ACLE 2448 intrinsics. These include: 2449 + The random number instructions that can be enabled through the 2450 (already present in GCC 9.1) +rng option extension. 2451 + Floating-point intrinsics to round to integer instructions 2452 from Armv8.5-A when targeting -march=armv8.5-a or later. 2453 + Memory Tagging Extension intrinsics enabled through the 2454 +memtag option extension. 2455 * Similarly, the following Armv8.6-A features are now supported 2456 through ACLE intrinsics: 2457 + The bfloat16 extension. This extension is enabled 2458 automatically when Armv8.6-A is selected (such as by 2459 -march=armv8.6-a). It can also be enabled for Armv8.2-A and 2460 later using the +bf16 option extension. 2461 + The Matrix Multiply extension. This extension is split into 2462 three parts, one for each supported data type: 2463 o Support for 8-bit integer matrix multiply instructions. 2464 This extension is enabled automatically when Armv8.6-A is 2465 selected. It can also be enabled for Armv8.2-A and later 2466 using the +i8mm option extension. 2467 o Support for 32-bit floating-point matrix multiply 2468 instructions. This extension can be enabled using the 2469 +f32mm option extension, which also has the effect of 2470 enabling SVE. 2471 o Support for 64-bit floating-point matrix multiply 2472 instructions. This extension can be enabled using the 2473 +f64mm option extension, which likewise has the effect of 2474 enabling SVE. 2475 * SVE2 is now supported through ACLE intrinsics and (to a limited 2476 extent) through autovectorization. It can be enabled through the 2477 +sve2 option extension (for example, -march=armv8.5-a+sve2). 2478 Additional extensions can be enabled through +sve2-sm4, +sve2-aes, 2479 +sve2-sha3 and +sve2-bitperm. 2480 * Support has been added for the following processors (GCC 2481 identifiers in parentheses): 2482 + Arm Cortex-A77 (cortex-a77). 2483 + Arm Cortex-A76AE (cortex-a76ae). 2484 + Arm Cortex-A65 (cortex-a65). 2485 + Arm Cortex-A65AE (cortex-a65ae). 2486 + Arm Cortex-A34 (cortex-a34). 2487 + Marvell ThunderX3 (thunderx3t110). 2488 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2489 options, for example: -mcpu=cortex-a77 or -mtune=cortex-a65ae or as 2490 arguments to the equivalent target attributes and pragmas. 2491 2492 arm 2493 2494 * Support for the FDPIC ABI has been added. It uses 64-bit function 2495 descriptors to represent pointers to functions, and enables code 2496 sharing on MMU-less systems. The corresponding target triple is 2497 arm-uclinuxfdpiceabi, and the C library is uclibc-ng. 2498 * Support has been added for the Arm EABI on NetBSD through the 2499 arm*-*-netbsdelf-*eabi* triplet. 2500 * The handling of 64-bit integer operations has been significantly 2501 reworked and improved leading to improved performance and reduced 2502 stack usage when using 64-bit integral data types. The option 2503 -mneon-for-64bits is now deprecated and will be removed in a future 2504 release. 2505 * Support has been added for the following processors (GCC 2506 identifiers in parentheses): 2507 + Arm Cortex-A77 (cortex-a77). 2508 + Arm Cortex-A76AE (cortex-a76ae). 2509 + Arm Cortex-M35P (cortex-m35p). 2510 + Arm Cortex-M55 (cortex-m55). 2511 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2512 options, for example: -mcpu=cortex-a77 or -mtune=cortex-m35p. 2513 * Support has been extended for the ACLE [43]data-processing 2514 intrinsics to include 32-bit SIMD, saturating arithmetic, 16-bit 2515 multiplication and other related intrinsics aimed at DSP algorithm 2516 optimization. 2517 * Support for -mpure-code in Thumb-1 (v6m) has been added: this 2518 M-profile feature is no longer restricted to targets with MOVT. For 2519 example, -mcpu=cortex-m0 now supports this option. 2520 * Support for the [44]Armv8.1-M Mainline Architecture has been added. 2521 + Armv8.1-M Mainline can be enabled by using the 2522 -march=armv8.1-m.main command-line option. 2523 * Support for the [45]MVE beta ACLE intrinsics has been added. These 2524 intrinsics can be enabled by including the arm_mve.h header file 2525 and passing the +mve or +mve.fp option extensions (for example: 2526 -march=armv8.1-m.main+mve). 2527 * Support for the Custom Datapath Extension beta ACLE [46]intrinsics 2528 has been added. 2529 * Support for Armv8.1-M Mainline Security Extensions architecture has 2530 been added. The -mcmse option, when used in combination with an 2531 Armv8.1-M Mainline architecture (for example: -march=armv8.1-m.main 2532 -mcmse), now leads to the generation of improved code sequences 2533 when changing security states. 2534 2535 AMD Radeon (GCN) 2536 2537 * Code generation and in particular vectorization support have been 2538 much improved. 2539 2540 ARC 2541 2542 * The interrupt service routine functions save all used registers, 2543 including extension registers and auxiliary registers used by Zero 2544 Overhead Loops. 2545 * Improve code size by using multiple short instructions instead of a 2546 single long mov or ior instruction when its long immediate constant 2547 is known. 2548 * Fix usage of the accumulator register for ARC600. 2549 * Fix issues with uncached attribute. 2550 * Remove -mq-class option. 2551 * Improve 64-bit integer addition and subtraction operations. 2552 2553 AVR 2554 2555 * Support for the XMEGA-like devices 2556 2557 ATtiny202, ATtiny204, ATtiny402, ATtiny404, ATtiny406, ATtiny804, 2558 ATtiny806, ATtiny807, ATtiny1604, ATtiny1606, ATtiny1607, ATmega808, 2559 ATmega809, ATmega1608, ATmega1609, ATmega3208, ATmega3209, 2560 ATmega4808, ATmega4809 2561 has been added. 2562 * A new command-line option -nodevicespecs has been added. It allows 2563 to provide a custom device-specs file by means of 2564 2565 avr-gcc -nodevicespecs -specs=my-spec-file <options> 2566 and without the need to provide options -B and -mmcu=. See [47]AVR 2567 command-line options for details. This feature is also available in 2568 GCC 9.3+ and GCC 8.4+. 2569 * New command-line options -mdouble=[32,64] and -mlong-double=[32,64] 2570 have been added. They allow to choose the size (in bits) of the 2571 double and long double types, respectively. Whether or not the 2572 mentioned layouts are available, whether the options act as a 2573 multilib option, and the default for either option are controlled 2574 by the new [48]AVR configure options --with-double= and 2575 --with-long-double=. 2576 * A new configure option --with-libf7= has been added. It controls to 2577 which level avr-libgcc provides 64-bit floating point support by 2578 means of [49]Libf7. 2579 * A new configure option --with-double-comparison= has been added. 2580 It's unlikely you need to set this option by hand. 2581 2582 IA-32/x86-64 2583 2584 * Support to expand __builtin_roundeven into the appropriate SSE 4.1 2585 instruction has been added. 2586 * New ISA extension support for Intel ENQCMD was added to GCC. ENQCMD 2587 intrinsics are available via the -menqcmd compiler switch. 2588 * GCC now supports the Intel CPU named Cooperlake through 2589 -march=cooperlake. The switch enables the AVX512BF16 ISA 2590 extensions. 2591 * GCC now supports the Intel CPU named Tigerlake through 2592 -march=tigerlake. The switch enables the MOVDIRI MOVDIR64B 2593 AVX512VP2INTERSECT ISA extensions. 2594 2595 MIPS 2596 2597 * The mips*-*-linux* targets now mark object files with appropriate 2598 GNU-stack note, facilitating use of non-executable stack hardening 2599 on GNU/Linux. The soft-float targets have this feature enabled by 2600 default, while for hard-float targets it is required for GCC to be 2601 configured with --with-glibc-version=2.31 against glibc 2.31 or 2602 later. 2603 2604 PowerPC / PowerPC64 / RS6000 2605 2606 * Many vector builtins have been listed as deprecated in the 2607 [50]64-Bit ELF V2 ABI Specification for quite a number of years. 2608 The vector builtins listed in Tables A.8 through A.10 are now 2609 deprecated for GCC 10, and will likely be removed from support in 2610 GCC 11. Note that this does not result in any loss of function. 2611 These deprecated builtins generally provide somewhat nonsensical 2612 argument lists (for example, mixing signed, unsigned, and bool 2613 vector arguments arbitrarily), or are duplicate builtins that are 2614 inconsistent with the expected naming scheme. We expect that this 2615 will be unlikely to affect much if any code, and any required code 2616 changes will be trivial. 2617 2618 PRU 2619 2620 * A new back end targeting TI PRU I/O processors has been contributed 2621 to GCC. 2622 2623 RISC-V 2624 2625 * The riscv*-*-* targets now require GNU binutils version 2.30 or 2626 later, to support new assembly instructions produced by GCC. 2627 2628 V850 2629 2630 * The ABI for V850 nested functions has been changed. Previously the 2631 V850 port used %r20 for the static chain pointer, now the port uses 2632 %r19. This corrects a long standing latent bug in the v850 port 2633 where a call to a nested function would unexpectedly change the 2634 value in %r20. 2635 2636 Operating Systems 2637 2638 Improvements for plugin authors 2639 2640 * GCC diagnostics can now have a chain of events associated with 2641 them, describing a path through the code that triggers the problem. 2642 These can be printed by the diagnostics subsystem in various ways, 2643 controlled by the [51]-fdiagnostics-path-format option, or captured 2644 in JSON form via [52]-fdiagnostics-format=json. 2645 * GCC diagnostics can now be associated with [53]CWE weakness 2646 identifiers, which will appear on the standard error stream, and in 2647 the JSON output from [54]-fdiagnostics-format=json. 2648 2649 Other significant improvements 2650 2651 * To allow inline expansion of both memcpy and memmove, the existing 2652 movmem instruction patterns used for non-overlapping memory copies 2653 have been renamed to cpymem. The movmem name is now used for 2654 overlapping memory moves, consistent with the library functions 2655 memcpy and memmove. 2656 * For many releases, when GCC emits a warning it prints the option 2657 controlling that warning. As of GCC 10, that option text is now a 2658 clickable hyperlink for the documentation of that option (assuming 2659 a [55]sufficiently capable terminal). This behavior can be 2660 controlled via a new [56]-fdiagnostics-urls option (along with 2661 various environment variables and heuristics documented with that 2662 option). 2663 2664 GCC 10.1 2665 2666 This is the [57]list of problem reports (PRs) from GCC's bug tracking 2667 system that are known to be fixed in the 10.1 release. This list might 2668 not be complete (that is, it is possible that some PRs that have been 2669 fixed are not listed here). 2670 2671 GCC 10.2 2672 2673 This is the [58]list of problem reports (PRs) from GCC's bug tracking 2674 system that are known to be fixed in the 10.2 release. This list might 2675 not be complete (that is, it is possible that some PRs that have been 2676 fixed are not listed here). 2677 2678 GCC 10.3 2679 2680 This is the [59]list of problem reports (PRs) from GCC's bug tracking 2681 system that are known to be fixed in the 10.3 release. This list might 2682 not be complete (that is, it is possible that some PRs that have been 2683 fixed are not listed here). 2684 2685 Target Specific Changes 2686 2687 AArch64 2688 2689 * A bug with the Random Number intrinsics in the arm_acle.h header 2690 that resulted in an incorrect status result being returned has been 2691 fixed. 2692 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 2693 options are -mcpu=a64fx and -mtune=a64fx respectively. In 2694 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 2695 tunes the code for the A64FX. This includes tuning the SVE code, 2696 although by default the code is still length-agnostic and so works 2697 for all SVE implementations. Adding -msve-vector-bits=512 makes the 2698 code specific to 512-bit SVE. 2699 2700 x86-64 2701 2702 * GCC 10.3 supports AMD CPUs based on the znver3 core via 2703 -march=znver3. 2704 2705 GCC 10.4 2706 2707 This is the [60]list of problem reports (PRs) from GCC's bug tracking 2708 system that are known to be fixed in the 10.4 release. This list might 2709 not be complete (that is, it is possible that some PRs that have been 2710 fixed are not listed here). 2711 2712 Target Specific Changes 2713 2714 x86-64 2715 2716 * The x86-64 ABI of passing and returning structures with a 64-bit 2717 integer vector changed in GCC 10.1 when MMX is disabled. Disabling 2718 MMX no longer changes how they are passed nor returned. This ABI 2719 change is now diagnosed with -Wpsabi. 2720 2721 2722 For questions related to the use of GCC, please consult these web 2723 pages and the [61]GCC manuals. If that fails, the 2724 [62]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 2725 web pages and the development of GCC are welcome on our developer 2726 list at [63]gcc (a] gcc.gnu.org. All of [64]our lists have public 2727 archives. 2728 2729 Copyright (C) [65]Free Software Foundation, Inc. Verbatim copying and 2730 distribution of this entire article is permitted in any medium, 2731 provided this notice is preserved. 2732 2733 These pages are [66]maintained by the GCC team. Last modified 2734 2023-03-11. 2735 2736 References 2737 2738 1. http://gcc.gnu.org/gcc-10/porting_to.html 2739 2. http://gcc.gnu.org/onlinedocs/index.html#current 2740 3. http://gcc.gnu.org/gcc-10/changes.html#empty_base 2741 4. https://www.mpfr.org/ 2742 5. http://gcc.gnu.org/gcc-10/changes.html#iterator_base 2743 6. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/cpp/_005f_005fhas_005fbuiltin.html#g_t_005f_005fhas_005fbuiltin 2744 7. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fno-allocation-dce 2745 8. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-partial-training 2746 9. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-reproducible 2747 10. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-generate 2748 11. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-prefix-path 2749 12. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html 2750 13. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-finline-functions 2751 14. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/lto-dump.html 2752 15. https://facebook.github.io/zstd/ 2753 16. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-values 2754 17. https://www.openacc.org/ 2755 18. https://gcc.gnu.org/wiki/OpenACC/Implementation%20Status#status-10 2756 19. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/libgomp/#toc-Enabling-OpenACC-1 2757 20. https://www.openmp.org/specifications/ 2758 21. https://gcc.gnu.org/wiki/Offloading 2759 22. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstring-compare 2760 23. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wzero-length-bounds 2761 24. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warray-bounds 2762 25. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wformat-overflow 2763 26. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wrestrict 2764 27. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wreturn-local-addr 2765 28. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstringop-overflow 2766 29. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warith-conversion 2767 30. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-tags 2768 31. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wredundant-tags 2769 32. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94383 2770 33. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711 2771 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94707 2772 35. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94704 2773 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94706 2774 37. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92285 2775 38. https://www.openmp.org/specifications/ 2776 39. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_major 2777 40. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_minor 2778 41. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_patchlevel 2779 42. https://gcc.gnu.org/onlinedocs/jit/topics/types.html#c.gcc_jit_context_new_bitfield 2780 43. https://developer.arm.com/documentation/101028/0009/Data-processing-intrinsics 2781 44. https://developer.arm.com/Architectures/M-Profile%20Architecture 2782 45. https://developer.arm.com/architectures/instruction-sets/intrinsics/ 2783 46. https://developer.arm.com/documentation/101028/0010/Custom-Datapath-Extension 2784 47. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/AVR-Options.html#index-nodevicespecs 2785 48. https://gcc.gnu.org/install/configure.html#avr 2786 49. https://gcc.gnu.org/wiki/avr-gcc#Libf7 2787 50. https://openpowerfoundation.org/?resource_lib=64-bit-elf-v2-abi-specification-power-architecture 2788 51. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-path-format 2789 52. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 2790 53. https://cwe.mitre.org/ 2791 54. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 2792 55. https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda 2793 56. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-urls 2794 57. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.0 2795 58. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.2 2796 59. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.3 2797 60. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.4 2798 61. https://gcc.gnu.org/onlinedocs/ 2799 62. mailto:gcc-help (a] gcc.gnu.org 2800 63. mailto:gcc (a] gcc.gnu.org 2801 64. https://gcc.gnu.org/lists.html 2802 65. https://www.fsf.org/ 2803 66. https://gcc.gnu.org/about.html 2804 ====================================================================== 2805 http://gcc.gnu.org/gcc-9/index.html 2806 2807 GCC 9 Release Series 2808 2809 (This release series is no longer supported.) 2810 2811 May 27, 2022 2812 2813 The [1]GNU project and the GCC developers are pleased to announce the 2814 release of GCC 9.5. 2815 2816 This release is a bug-fix release, containing fixes for regressions in 2817 GCC 9.4 relative to previous releases of GCC. 2818 2819 Release History 2820 2821 GCC 9.5 2822 May 27, 2022 ([2]changes, [3]documentation) 2823 2824 GCC 9.4 2825 June 1, 2021 ([4]changes, [5]documentation) 2826 2827 GCC 9.3 2828 Mar 12, 2020 ([6]changes, [7]documentation) 2829 2830 GCC 9.2 2831 Aug 12, 2019 ([8]changes, [9]documentation) 2832 2833 GCC 9.1 2834 May 3, 2019 ([10]changes, [11]documentation) 2835 2836 References and Acknowledgements 2837 2838 GCC used to stand for the GNU C Compiler, but since the compiler 2839 supports several other languages aside from C, it now stands for the 2840 GNU Compiler Collection. 2841 2842 A list of [12]successful builds is updated as new information becomes 2843 available. 2844 2845 The GCC developers would like to thank the numerous people that have 2846 contributed new features, improvements, bug fixes, and other changes as 2847 well as test results to GCC. This [13]amazing group of volunteers is 2848 what makes GCC successful. 2849 2850 For additional information about GCC please refer to the [14]GCC 2851 project web site or contact the [15]GCC development mailing list. 2852 2853 To obtain GCC please use [16]our mirror sites or [17]our version 2854 control system. 2855 2856 2857 For questions related to the use of GCC, please consult these web 2858 pages and the [18]GCC manuals. If that fails, the 2859 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 2860 web pages and the development of GCC are welcome on our developer 2861 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 2862 archives. 2863 2864 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 2865 distribution of this entire article is permitted in any medium, 2866 provided this notice is preserved. 2867 2868 These pages are [23]maintained by the GCC team. Last modified 2869 2022-10-26. 2870 2871 References 2872 2873 1. http://www.gnu.org/ 2874 2. http://gcc.gnu.org/gcc-9/changes.html 2875 3. http://gcc.gnu.org/onlinedocs/9.5.0/ 2876 4. http://gcc.gnu.org/gcc-9/changes.html 2877 5. http://gcc.gnu.org/onlinedocs/9.4.0/ 2878 6. http://gcc.gnu.org/gcc-9/changes.html 2879 7. http://gcc.gnu.org/onlinedocs/9.3.0/ 2880 8. http://gcc.gnu.org/gcc-9/changes.html 2881 9. http://gcc.gnu.org/onlinedocs/9.2.0/ 2882 10. http://gcc.gnu.org/gcc-9/changes.html 2883 11. http://gcc.gnu.org/onlinedocs/9.1.0/ 2884 12. http://gcc.gnu.org/gcc-9/buildstat.html 2885 13. http://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Contributors.html 2886 14. http://gcc.gnu.org/index.html 2887 15. mailto:gcc (a] gcc.gnu.org 2888 16. http://gcc.gnu.org/mirrors.html 2889 17. http://gcc.gnu.org/git.html 2890 18. https://gcc.gnu.org/onlinedocs/ 2891 19. mailto:gcc-help (a] gcc.gnu.org 2892 20. mailto:gcc (a] gcc.gnu.org 2893 21. https://gcc.gnu.org/lists.html 2894 22. https://www.fsf.org/ 2895 23. https://gcc.gnu.org/about.html 2896 ====================================================================== 2897 http://gcc.gnu.org/gcc-9/changes.html 2898 2899 GCC 9 Release Series 2900 Changes, New Features, and Fixes 2901 2902 This page is a "brief" summary of some of the huge number of 2903 improvements in GCC 9. You may also want to check out our [1]Porting to 2904 GCC 9 page and the [2]full GCC documentation. 2905 2906 Caveats 2907 2908 * On Arm targets (arm*-*-*), [3]a bug in the implementation of the 2909 procedure call standard (AAPCS) in the GCC 6, 7 and 8 releases has 2910 been fixed: a structure containing a bit-field based on a 64-bit 2911 integral type and where no other element in a structure required 2912 64-bit alignment could be passed incorrectly to functions. This is 2913 an ABI change. If the option -Wpsabi is enabled (on by default) the 2914 compiler will emit a diagnostic note for code that might be 2915 affected. 2916 * Support for a number of older systems and recently unmaintained or 2917 untested target ports of GCC has been declared obsolete in GCC 9. 2918 Unless there is activity to revive them, the next release of GCC 2919 will have their sources permanently removed. 2920 The following ports for individual systems on particular 2921 architectures have been obsoleted: 2922 + Solaris 10 (*-*-solaris2.10). Details can be found in the 2923 [4]announcement. 2924 + Cell Broadband Engine SPU (spu*-*-*). Details can be found in 2925 the [5]announcement. 2926 * A change to the C++ std::rotate algorithm in GCC 9.1.0 can cause 2927 ABI incompatibilities with object files compiled with other 2928 versions of GCC. If the std::rotate algorithm is called with an 2929 empty range then it might cause a divide-by-zero error (as a SIGFPE 2930 signal) and crash. The change has been reverted for GCC 9.2.0 and 2931 future releases. For more details see [6]Bug 90920. The problem can 2932 be avoided by recompiling any objects that might call std::rotate 2933 with an empty range, so that the GCC 9.1.0 definition of 2934 std::rotate is not used. 2935 * The automatic template instantiation at link time ([7]-frepo) has 2936 been deprecated and will be removed in a future release. 2937 * The --with-default-libstdcxx-abi=gcc4-compatible configure option 2938 is broken in the 9.1 and 9.2 releases, producing a shared library 2939 with missing symbols (see [8]Bug 90361). As a workaround, configure 2940 without that option and build GCC as normal, then edit the 2941 installed <bits/c++config.h> headers to define the 2942 _GLIBCXX_USE_CXX11_ABI macro to 0. 2943 2944 General Improvements 2945 2946 The following GCC command line options have been introduced or 2947 improved. 2948 * All command line options that take a byte-size argument accept 2949 64-bit integers as well as standard SI and IEC suffixes such as kb 2950 and KiB, MB and MiB, or GB and GiB denoting the corresponding 2951 multiples of bytes. See [9]Invoking GCC for more. 2952 * A new option [10]-flive-patching=[inline-only-static|inline-clone] 2953 generates code suitable for live patching. At the same time it 2954 provides multiple-level control over IPA optimizations. See the 2955 user guide for more details. 2956 * A new option, --completion, has been added to provide more fine 2957 option completion in a shell. It is intended to be used by 2958 Bash-completion. 2959 * GCC's diagnostics now print source code with a left margin showing 2960 line numbers, configurable with 2961 [11]-fno-diagnostics-show-line-numbers. 2962 GCC's diagnostics can also now label regions of the source code to 2963 show pertinent information, such as the types within an expression. 2964 $ g++ t.cc 2965 t.cc: In function 'int test(const shape&, const shape&)': 2966 t.cc:15:4: error: no match for 'operator+' (operand types are 'boxed_value<doubl 2967 e>' and 'boxed_value<double>') 2968 14 | return (width(s1) * height(s1) 2969 | ~~~~~~~~~~~~~~~~~~~~~~ 2970 | | 2971 | boxed_value<[...]> 2972 15 | + width(s2) * height(s2)); 2973 | ^ ~~~~~~~~~~~~~~~~~~~~~~ 2974 | | 2975 | boxed_value<[...]> 2976 2977 These labels can be disabled via [12]-fno-diagnostics-show-labels. 2978 * A new option [13]-fdiagnostics-format=json has been introduced for 2979 emitting diagnostics in a machine-readable format. 2980 * The alignment-related options [14]-falign-functions, 2981 [15]-falign-labels, [16]-falign-loops, and [17]-falign-jumps 2982 received support for a secondary alignment (e.g. 2983 -falign-loops=n:m:n2:m2). 2984 * New pair of profiling options ([18]-fprofile-filter-files and 2985 [19]-fprofile-exclude-files) has been added. The options help to 2986 filter which source files are instrumented. 2987 * AddressSanitizer generates more compact redzones for automatic 2988 variables. That helps to reduce memory footprint of a sanitized 2989 binary. 2990 * Numerous improvements have been made to the output of 2991 [20]-fopt-info. 2992 Messages are now prefixed with optimized, missed, or note, rather 2993 than the old behavior of all being prefixed with note. 2994 The output from -fopt-info can now contain information on inlining 2995 decisions: 2996 $ g++ -c inline.cc -O2 -fopt-info-inline-all 2997 inline.cc:24:11: note: Considering inline candidate void foreach(T, T, void (*)( 2998 E)) [with T = char**; E = char*]/2. 2999 inline.cc:24:11: optimized: Inlining void foreach(T, T, void (*)(E)) [with T = 3000 char**; E = char*]/2 into int main(int, char**)/1. 3001 inline.cc:19:12: missed: not inlinable: void inline_me(char*)/0 -> int std::pu 3002 ts(const char*)/3, function body not available 3003 inline.cc:13:8: optimized: Inlined void inline_me(char*)/4 into int main(int, c 3004 har**)/1 which now has time 127.363637 and size 11, net change of +0. 3005 Unit growth for small function inlining: 16->16 (0%) 3006 3007 Inlined 2 calls, eliminated 1 functions 3008 3009 3010 The output from the vectorizer has been rationalized so that failed 3011 attempts to vectorize a loop are displayed in the form 3012 [LOOP-LOCATION]: couldn't vectorize this loop 3013 [PROBLEM-LOCATION]: because of [REASON] 3014 3015 rather than an exhaustive log of all decisions made by the 3016 vectorizer. For example: 3017 $ gcc -c v.c -O3 -fopt-info-all-vec 3018 v.c:7:3: missed: couldn't vectorize loop 3019 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 3020 mory"); 3021 v.c:3:6: note: vectorized 0 loops in function. 3022 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 3023 mory"); 3024 3025 The old behavior can be obtained via a new -internals suboption of 3026 -fopt-info. 3027 * A new option, [21]-fsave-optimization-record has been added, which 3028 writes a SRCFILE.opt-record.json.gz file describing the 3029 optimization decisions made by GCC. This is similar to the output 3030 of -fopt-info, but with additional metadata such as the inlining 3031 chain, and profile information (if available). 3032 * Inter-procedural propagation of stack alignment can now be 3033 controlled by [22]-fipa-stack-alignment. 3034 * Propagation of addressability, readonly and writeonly flags on 3035 static variables can now be controlled by 3036 [23]-fipa-reference-addressable. 3037 3038 The following built-in functions have been introduced. 3039 * [24]__builtin_expect_with_probability to provide branch prediction 3040 probability hints to the optimizer. 3041 * [25]__builtin_has_attribute determines whether a function, type, or 3042 variable has been declared with some attribute. 3043 * [26]__builtin_speculation_safe_value can be used to help mitigate 3044 against unsafe speculative execution. 3045 3046 The following attributes have been introduced. 3047 * The [27]copy function attribute has been added. The attribute can 3048 also be applied to type definitions and to variable declarations. 3049 3050 A large number of improvements to code generation have been made, 3051 including but not limited to the following. 3052 * Switch expansion has been improved by using a different strategy 3053 (jump table, bit test, decision tree) for a subset of switch cases. 3054 * A linear function expression defined as a switch statement can be 3055 transformed by [28]-ftree-switch-conversion. For example: 3056 3057 int 3058 foo (int how) 3059 { 3060 switch (how) { 3061 case 2: how = 205; break; 3062 case 3: how = 305; break; 3063 case 4: how = 405; break; 3064 case 5: how = 505; break; 3065 case 6: how = 605; break; 3066 } 3067 return how; 3068 } 3069 3070 can be transformed into 100 * how + 5 (for values defined in the 3071 switch statement). 3072 * Inter-procedural optimization improvements: 3073 + Inliner defaults was tuned to better suits modern C++ 3074 codebases especially when built with link time optimizations. 3075 New parameters max-inline-insns-small, max-inline-insns-size, 3076 uninlined-function-insns, uninlined-function-time, 3077 uninlined-thunk-insns, and uninlined-thunk-time were added. 3078 + Hot/cold partitioning is now more precise and aggressive. 3079 + Improved scalability for very large translation units 3080 (especially when link-time optimizing large programs). 3081 * Profile driven optimization improvements: 3082 + [29]-fprofile-use now enables [30]-fversion-loops-for-strides, 3083 [31]-floop-interchange, [32]-floop-unroll-and-jam, 3084 [33]-ftree-loop-distribution. 3085 + Streaming of counter histograms was removed. This reduces the 3086 size of profile files. Histogram is computed on the fly with 3087 link-time optimization. Parameter hot-bb-count-ws-permille was 3088 reduced from 999 to 990 to account for more precise 3089 histograms. 3090 * Link-time optimization improvements: 3091 + Types are now simplified prior streaming resulting in 3092 significant reductions of the LTO object files, link-time 3093 memory use, and improvements of link-time parallelism. 3094 + Default number of partitions (--param lto-partitions) was 3095 increased from 32 to 128 enabling effective use of CPUs with 3096 more than 32 hyperthreads. --param 3097 lto-max-streaming-parallelism can now be used to control 3098 number of streaming processes. 3099 + Warnings on C++ One Decl Rule violations (-Wodr) are now more 3100 informative and produce fewer redundant results. 3101 Overall compile time of Firefox 66 and LibreOffice 6.2.3 on an 3102 8-core machine was reduced by about 5% compared to GCC 8.3, and the 3103 size of LTO object files by 7%. LTO link-time improves by 11% on an 3104 8-core machine and scales significantly better for more parallel 3105 build environments. The serial stage of the link-time optimization 3106 is 28% faster consuming 20% less memory. The parallel stage now 3107 scales to up to 128 partitions rather than 32 and reduces memory 3108 use for every worker by 30%. 3109 3110 The following improvements to the gcov command-line utility have been 3111 made. 3112 * The gcov tool received a new option [34]--use-hotness-colors (-q) 3113 that can provide perf-like coloring of hot functions. 3114 * The gcov tool has changed its intermediate format to a new JSON 3115 format. 3116 3117 New Languages and Language specific improvements 3118 3119 [35]OpenACC support in C, C++, and Fortran continues to be maintained 3120 and improved. Most of the OpenACC 2.5 specification is implemented. See 3121 the [36]implementation status section on the OpenACC wiki page for 3122 further information. 3123 3124 C family 3125 3126 * Version 5.0 of the [37]OpenMP specification is now partially 3127 supported in the C and C++ compilers. For details which features of 3128 OpenMP 5.0 are and which are not supported in the GCC 9 release see 3129 [38]this mail. 3130 * New extensions: 3131 + [39]__builtin_convertvector built-in for vector conversions 3132 has been added. 3133 * New warnings: 3134 + [40]-Waddress-of-packed-member, enabled by default, warns 3135 about an unaligned pointer value from the address of a packed 3136 member of a struct or union. 3137 * Enhancements to existing warnings: 3138 + [41]-Warray-bounds detects more instances of out-of-bounds 3139 indices. 3140 + [42]-Wattribute-alias also detects attribute mismatches 3141 between alias declarations and their targets, in addition to 3142 mismatches between their types. 3143 + [43]-Wformat-overflow and [44]-Wformat-truncation have been 3144 extended to all formatted input/output functions (where 3145 applicable) and enhanced to detect a subset of instances of 3146 reading past the end of unterminated constant character arrays 3147 in %s directives. 3148 + [45]-Wmissing-attributes detects instances of missing function 3149 attributes on declarations of aliases and weak references. 3150 + [46]-Wstringop-truncation also detects a subset of instances 3151 of reading past the end of unterminated constant character 3152 arrays, 3153 * If a macro is used with the wrong argument count, the C and C++ 3154 front ends now show the definition of that macro via a note. 3155 * The spelling corrector now considers transposed letters, and the 3156 threshold for similarity has been tightened, to avoid nonsensical 3157 suggestions. 3158 3159 C 3160 3161 * There is now experimental support for -std=c2x, to select support 3162 for the upcoming C2X revision of the ISO C standard. This standard 3163 is in the early stages of development and the only feature 3164 supported in GCC 9 is _Static_assert with a single argument 3165 (support for _Static_assert with two arguments was added in C11 and 3166 GCC 4.6). There are also new options -std=gnu2x, for C2X with GNU 3167 extensions, and -Wc11-c2x-compat, to warn for uses of features 3168 added in C2X (such warnings are also enabled by use of -Wpedantic 3169 if not using -std=c2x or -std=gnu2x). 3170 * New warnings: 3171 + [47]-Wabsolute-value warns for calls to standard functions 3172 that compute the absolute value of an argument when a more 3173 appropriate standard function is available. For example, 3174 calling abs(3.14) triggers the warning because the appropriate 3175 function to call to compute the absolute value of a double 3176 argument is fabs. The option also triggers warnings when the 3177 argument in a call to such a function has an unsigned type. 3178 This warning can be suppressed with an explicit type cast and 3179 it is also enabled by -Wextra. 3180 3181 C++ 3182 3183 * New warnings: 3184 + [48]-Wdeprecated-copy, implied by -Wextra, warns about the 3185 C++11 deprecation of implicitly declared copy constructor and 3186 assignment operator if one of them is user-provided. 3187 -Wdeprecated-copy-dtor also warns if the destructor is 3188 user-provided, as specified in C++11. 3189 + [49]-Winit-list-lifetime, on by default, warns about uses of 3190 std::initializer_list that are likely to result in a dangling 3191 pointer, such as returning or assigning from a temporary list. 3192 + [50]-Wredundant-move, implied by -Wextra, warns about 3193 redundant calls to std::move. 3194 + [51]-Wpessimizing-move, implied by -Wall, warns when a call to 3195 std::move prevents copy elision. 3196 + [52]-Wclass-conversion, on by default, warns when a conversion 3197 function will never be called due to the type it converts to. 3198 * The C++ front end has experimental support for some of the upcoming 3199 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 3200 including range-based for statements with initializer, default 3201 constructible and assignable stateless lambdas, lambdas in 3202 unevaluated contexts, language support for empty data members, 3203 allowing pack expansion in lambda init-capture, likely and unlikely 3204 attributes, class types in non-type template parameters, allowing 3205 virtual function calls in constant expressions, explicit(bool), 3206 std::is_constant_evaluated, nested inline namespaces, etc. For a 3207 full list of new features, see [53]the C++ status page. 3208 * The C++ front end now preserves source locations for literals, 3209 id-expression, and mem-initializer for longer. For example it is 3210 now able to pin-point the pertinent locations for bad 3211 initializations such as these 3212 $ g++ -c bad-inits.cc 3213 bad-inits.cc:10:14: error: cannot convert 'json' to 'int' in initialization 3214 10 | { 3, json::object }, 3215 | ~~~~~~^~~~~~ 3216 | | 3217 | json 3218 bad-inits.cc:14:31: error: initializer-string for array of chars is too long [-f 3219 permissive] 3220 14 | char buffers[3][5] = { "red", "green", "blue" }; 3221 | ^~~~~~~ 3222 bad-inits.cc: In constructor 'X::X()': 3223 bad-inits.cc:17:13: error: invalid conversion from 'int' to 'void*' [-fpermissiv 3224 e] 3225 17 | X() : one(42), two(42), three(42) 3226 | ^~ 3227 | | 3228 | int 3229 3230 rather than emitting the error at the final closing parenthesis or 3231 brace. 3232 * Error-reporting of overload resolution has been special-cased to 3233 make the case of a single failed candidate easier to read. For 3234 example: 3235 $ g++ param-type-mismatch.cc 3236 param-type-mismatch.cc: In function 'int test(int, const char*, float)': 3237 param-type-mismatch.cc:8:32: error: cannot convert 'const char*' to 'const char* 3238 *' 3239 8 | return foo::member_1 (first, second, third); 3240 | ^~~~~~ 3241 | | 3242 | const char* 3243 param-type-mismatch.cc:3:46: note: initializing argument 2 of 'static int foo: 3244 :member_1(int, const char**, float)' 3245 3 | static int member_1 (int one, const char **two, float three); 3246 | ~~~~~~~~~~~~~^~~ 3247 3248 highlights both the problematic argument, and the parameter that it 3249 can't be converted to. 3250 * Diagnostics involving binary operators now use color to distinguish 3251 the two operands, and label them separately (as per the example of 3252 source labelling above). 3253 * Diagnostics involving function calls now highlight the pertinent 3254 parameter of the declaration in more places. 3255 $ g++ bad-conversion.cc 3256 bad-conversion.cc: In function 'void caller()': 3257 bad-conversion.cc:9:14: error: cannot convert 'bool' to 'void*' 3258 9 | callee (0, false, 2); 3259 | ^~~~~ 3260 | | 3261 | bool 3262 bad-conversion.cc:3:19: note: initializing argument 2 of 'void callee(int, voi 3263 d*, int)' 3264 3 | void callee (int, void *, int) 3265 | ^~~~~~ 3266 3267 * The C++ front end's implementation of [54]-Wformat now shows 3268 precise locations within string literals, and underlines the 3269 pertinent arguments at bogus call sites (the C front end has been 3270 doing this since GCC 7). For example: 3271 $ g++ -c bad-printf.cc -Wall 3272 bad-printf.cc: In function 'void print_field(const char*, float, long int, long 3273 int)': 3274 bad-printf.cc:6:17: warning: field width specifier '*' expects argument of type 3275 'int', but argument 3 has type 'long int' [-Wformat=] 3276 6 | printf ("%s: %*ld ", fieldname, column - width, value); 3277 | ~^~~ ~~~~~~~~~~~~~~ 3278 | | | 3279 | int long int 3280 bad-printf.cc:6:19: warning: format '%ld' expects argument of type 'long int', b 3281 ut argument 4 has type 'double' [-Wformat=] 3282 6 | printf ("%s: %*ld ", fieldname, column - width, value); 3283 | ~~~^ ~~~~~ 3284 | | | 3285 | long int double 3286 | %*f 3287 3288 * The C++ front end has gained new fix-it hints for forgetting the 3289 return *this; needed by various C++ operators: 3290 $ g++ -c operator.cc 3291 operator.cc: In member function 'boxed_ptr& boxed_ptr::operator=(const boxed_ptr 3292 &)': 3293 operator.cc:7:3: warning: no return statement in function returning non-void [-W 3294 return-type] 3295 6 | m_ptr = other.m_ptr; 3296 +++ |+ return *this; 3297 7 | } 3298 | ^ 3299 3300 for when the compiler needs a typename: 3301 $ g++ -c template.cc 3302 template.cc:3:3: error: need 'typename' before 'Traits::type' because 'Traits' i 3303 s a dependent scope 3304 3 | Traits::type type; 3305 | ^~~~~~ 3306 | typename 3307 3308 when trying to use an accessor member as if it were a data member: 3309 $ g++ -c fncall.cc 3310 fncall.cc: In function 'void hangman(const mystring&)': 3311 fncall.cc:12:11: error: invalid use of member function 'int mystring::get_length 3312 () const' (did you forget the '()' ?) 3313 12 | if (str.get_length > 0) 3314 | ~~~~^~~~~~~~~~ 3315 | () 3316 3317 for C++11's scoped enums: 3318 $ g++ -c enums.cc 3319 enums.cc: In function 'void json::test(const json::value&)': 3320 enums.cc:12:26: error: 'STRING' was not declared in this scope; did you mean 'js 3321 on::kind::STRING'? 3322 12 | if (v.get_kind () == STRING) 3323 | ^~~~~~ 3324 | json::kind::STRING 3325 enums.cc:3:44: note: 'json::kind::STRING' declared here 3326 3 | enum class kind { OBJECT, ARRAY, NUMBER, STRING, TRUE, FALSE, NULL_ }; 3327 | ^~~~~~ 3328 3329 and a tweak to integrate the suggestions about misspelled members 3330 with that for accessors: 3331 $ g++ -c accessor-fixit.cc 3332 accessor-fixit.cc: In function 'int test(t*)': 3333 accessor-fixit.cc:17:15: error: 'class t' has no member named 'ratio'; did you m 3334 ean 'int t::m_ratio'? (accessible via 'int t::get_ratio() const') 3335 17 | return ptr->ratio; 3336 | ^~~~~ 3337 | get_ratio() 3338 3339 In addition, various diagnostics in the C++ front-end have been 3340 streamlined by consolidating the suggestion into the initial error, 3341 rather than emitting a follow-up note: 3342 $ g++ typo.cc 3343 typo.cc:5:13: error: 'BUFSIZE' was not declared in this scope; did you mean 'BUF 3344 _SIZE'? 3345 5 | uint8_t buf[BUFSIZE]; 3346 | ^~~~~~~ 3347 | BUF_SIZE 3348 3349 Runtime Library (libstdc++) 3350 3351 * Improved support for C++17, including: 3352 + The C++17 implementation is no longer experimental. 3353 + Parallel algorithms and <execution> (requires [55]Thread 3354 Building Blocks 2018 or newer). 3355 + <memory_resource>. 3356 + Using the types and functions in <filesystem> does not require 3357 linking with -lstdc++fs now. 3358 * Improved experimental support for C++2a, including: 3359 + Type traits std::remove_cvref, std::unwrap_reference, 3360 std::unwrap_decay_ref, std::is_nothrow_convertible, and 3361 std::type_identity. 3362 + Headers <bit> and <version>. 3363 + Uniform container erasure (std::erase_if). 3364 + contains member of maps and sets. 3365 + String prefix and suffix checking (starts_with, ends_with). 3366 + Functions std::midpoint and std::lerp for interpolation. 3367 + std::bind_front. 3368 + std::visit<R>. 3369 + std::assume_aligned. 3370 + Uses-allocator construction utilities. 3371 + std::pmr::polymorphic_allocator<std::byte>. 3372 + Library support for char8_t type. 3373 + Destroying delete. 3374 + std::is_constant_evaluated() function. 3375 * Support for opening file streams with wide character paths on 3376 Windows 3377 * Incomplete support for the C++17 Filesystem library and the 3378 Filesystem TS on Windows. 3379 * Incomplete, experimental support for the Networking TS. 3380 3381 D 3382 3383 * Support for the D programming language has been added to GCC, 3384 implementing version 2.076 of the language and run-time library. 3385 3386 Fortran 3387 3388 * Asynchronous I/O is now fully supported. The program needs to be 3389 linked against the pthreads library to use it, otherwise the I/O is 3390 done synchronously. For systems which do not support POSIX 3391 condition variables, such as AIX, all I/O is still done 3392 synchronously. 3393 * The BACK argument for MINLOC and MAXLOC has been implemented. 3394 * The FINDLOC intrinsic function has been implemented. 3395 * The IS_CONTIGUOUS intrinsic function has been implemented. 3396 * Direct access to the real and imaginary parts of a complex variable 3397 via c%re and c%im has been implemented. 3398 * Type parameter inquiry via str%len and a%kind has been implemented. 3399 * C descriptors and the ISO_Fortran_binding.h source file have been 3400 implemented. 3401 * The MAX and MIN intrinsics are no longer guaranteed to return any 3402 particular value in case one of the arguments is a NaN. Note that 3403 this conforms to the Fortran standard and to what other Fortran 3404 compilers do. If there is a need to handle that case in some 3405 specific way, one needs to explicitly check for NaN's before 3406 calling MAX or MIN, e.g. by using the IEEE_IS_NAN function from the 3407 intrinsic module IEEE_ARITHMETIC. 3408 * A new command-line option [56]-fdec-include, set also by the 3409 [57]-fdec option, has been added to increase compatibility with 3410 legacy code. With this option, an INCLUDE directive is also parsed 3411 as a statement, which allows the directive to be spread across 3412 multiple source lines with line continuations. 3413 * A new [58]BUILTIN directive, has been added. The purpose of the 3414 directive is to provide an API between the GCC compiler and the GNU 3415 C Library which would define vector implementations of math 3416 routines. 3417 3418 Go 3419 3420 * GCC 9 provides a complete implementation of the Go 1.12.2 user 3421 packages. 3422 3423 libgccjit 3424 3425 * The libgccjit API gained a new entry point: 3426 [59]gcc_jit_context_add_driver_option. 3427 3428 New Targets and Target Specific Improvements 3429 3430 AArch64 & Arm 3431 3432 * Support has been added for the following processors (GCC 3433 identifiers in parentheses): 3434 + Arm Cortex-A76 (cortex-a76). 3435 + Arm Cortex-A55/Cortex-A76 DynamIQ big.LITTLE 3436 (cortex-a76.cortex-a55). 3437 + Arm Neoverse N1 (neoverse-n1). 3438 The GCC identifiers can be used as arguments to the -mcpu or -mtune 3439 options, for example: -mcpu=cortex-a76 or 3440 -mtune=cortex-a76.cortex-a55 or as arguments to the equivalent 3441 target attributes and pragmas. 3442 * The Armv8.3-A complex number instructions are now supported via 3443 intrinsics when the option -march=armv8.3-a or equivalent is 3444 specified. For the half-precision floating-point variants of these 3445 instructions use the architecture extension flag +fp16, e.g. 3446 -march=armv8.3-a+fp16. 3447 The intrinsics are defined by the ACLE specification. 3448 * The Armv8.5-A architecture is now supported through the 3449 -march=armv8.5-a option. 3450 * The Armv8.5-A architecture also adds some security features that 3451 are optional to all older architecture versions. These are now 3452 supported and only affect the assembler. 3453 + Speculation Barrier instruction through the -march=armv8-a+sb 3454 option. 3455 + Execution and Data Prediction Restriction instructions through 3456 the -march=armv8-a+predres option. 3457 + Speculative Store Bypass Safe instruction through the 3458 -march=armv8-a+ssbs option. This does not require a compiler 3459 option for Arm and thus -march=armv8-a+ssbs is an 3460 AArch64-specific option. 3461 3462 AArch64 specific 3463 3464 * Support has been added for the Arm Neoverse E1 processor 3465 (-mcpu=neoverse-e1). 3466 * The AArch64 port now has support for stack clash protection using 3467 the [60]-fstack-clash-protection option. The probing interval/guard 3468 size can be set by using --param 3469 stack-clash-protection-guard-size=12|16. The value of this 3470 parameter must be in bytes represented as a power of two. The two 3471 supported values for this parameter are 12 (for a 4KiB size, 2^12) 3472 and 16 (for a 64KiB size, 2^16). The default value is 16 (64Kb) and 3473 can be changed at configure time using the flag 3474 --with-stack-clash-protection-guard-size=12|16. 3475 * The option -msign-return-address= has been deprecated. This has 3476 been replaced by the new -mbranch-protection= option. This new 3477 option can now be used to enable the return address signing as well 3478 as the new Branch Target Identification feature of Armv8.5-A 3479 architecture. For more information on the arguments accepted by 3480 this option, please refer to [61]AArch64-Options. 3481 * The following optional extensions to Armv8.5-A architecture are now 3482 supported and only affect the assembler. 3483 + Random Number Generation instructions through the 3484 -march=armv8.5-a+rng option. 3485 + Memory Tagging Extension through the -march=armv8.5-a+memtag 3486 option. 3487 3488 Arm specific 3489 3490 * Support for the deprecated Armv2 and Armv3 architectures and their 3491 variants has been removed. Their corresponding -march values and 3492 the -mcpu options that used these architectures have been removed. 3493 * Support for the Armv5 and Armv5E architectures (which have no known 3494 implementations) has been removed. Note that Armv5T, Armv5TE and 3495 Armv5TEJ architectures remain supported. 3496 * Corrected FPU configurations for Cortex-R7 and Cortex-R8 when using 3497 their respective -mcpu options. 3498 3499 AMD GCN 3500 3501 * A new back end targeting AMD GCN GPUs has been contributed to GCC. 3502 The implementation is currently limited to compiling 3503 single-threaded, stand-alone programs. Future versions will add 3504 support for offloading multi-threaded kernels via OpenMP and 3505 OpenACC. The following devices are supported (GCC identifiers in 3506 parentheses): 3507 + Fiji (fiji). 3508 + Vega 10 (gfx900). 3509 3510 ARC 3511 3512 * LRA is now on by default for the ARC target. This can be controlled 3513 by -mlra. 3514 * Add support for frame code-density and branch-and-index 3515 instructions. 3516 3517 C-SKY 3518 3519 * A new back end targeting C-SKY V2 processors has been contributed 3520 to GCC. 3521 3522 IA-32/x86-64 3523 3524 * Support of Intel MPX (Memory Protection Extensions) has been 3525 removed. 3526 * New ISA extension support for Intel PTWRITE was added to GCC. 3527 PTWRITE intrinsics are available via the -mptwrite compiler switch. 3528 * GCC now supports the Intel CPU named Cascade Lake with AVX512 3529 extensions through -march=cascadelake. The switch enables the 3530 following ISA extensions: AVX512F, AVX512VL, AVX512CD, AVX512BW, 3531 AVX512DQ, AVX512VNNI. 3532 3533 MIPS 3534 3535 * The Loongson loongson-mmi and loongson-ext extensions have been 3536 split from loongson3a: 3537 + loongson-mmi contains the Loongson MMI (MultiMedia extensions 3538 Instructions). 3539 + loongson-ext contains the Loongson EXT (EXTensions 3540 instructions). 3541 * The Loongson EXT2 (EXTensions R2 instructions) are now supported. 3542 + loongson-ext2 contains the Loongson EXT2 instructions. 3543 Command-line options-m[no-]loongson-mmi, -m[no-]loongson-ext, and 3544 -m[no-]loongson-ext2 enable or disable those extensions. 3545 * Support has been added for the following processors (GCC 3546 identifiers in parentheses): 3547 + Loongson 3A1000 (gs464) which enables loongson-mmi, 3548 loongson-ext by default. 3549 + Loongson 3A2000/3A3000 (gs464e) which enables loongson-mmi, 3550 loongson-ext, loongson-ext2 by default. 3551 + Loongson 2K1000 (gs264e) which enables loongson-ext, 3552 loongson-ext2, msa by default. 3553 The GCC identifiers can be used as arguments to the -mcpu and 3554 -mtune options (as in -mcpu=gs464 or -mtune=gs464e) or as arguments 3555 to the equivalent target attributes and pragmas. 3556 3557 OpenRISC 3558 3559 * A new back end targeting OpenRISC processors has been contributed 3560 to GCC. 3561 3562 S/390, System z, IBM z Systems 3563 3564 * Support for the arch13 architecture has been added. When using the 3565 -march=arch13 option, the compiler will generate code making use of 3566 the new instructions introduced with the vector enhancement 3567 facility 2 and the miscellaneous instruction extension facility 2. 3568 The -mtune=arch13 option enables arch13 specific instruction 3569 scheduling without making use of new instructions. 3570 * Builtins for the new vector instructions have been added and can be 3571 enabled using the -mzvector option. 3572 * Support for ESA architecture machines g5 and g6 is deprecated since 3573 GCC 6.1.0 and has been removed now. 3574 * When compiling with -march=z14 or higher GCC emits alignments hints 3575 on the vector load/store instructions (8 or 16 byte). 3576 * Functions now have a default alignment of 16 bytes. This helps with 3577 branch prediction effects. 3578 * -mfentry is now supported. As well as the mcount mechanism the 3579 __fentry__ is called before the function prologue. However, since 3580 just a single instruction is required to call __fentry__ the call 3581 sequence imposes a smaller overhead than mcount (4 instructions). 3582 The produced code is compatible only with newer glibc versions, 3583 which provide the __fentry__ symbol and do not clobber r0 when 3584 resolving lazily bound functions. -mfentry is only supported when 3585 generating 64 bit code and does not work with nested C functions. 3586 * The -mnop-mcount option can be used to emit NOP instructions 3587 instead of an mcount or fentry call stub. 3588 * With the -mrecord-mcount option a __mcount_loc section is generated 3589 containing pointers to each profiling call stub. This is useful for 3590 automatically patching in and out calls. 3591 3592 Operating Systems 3593 3594 Solaris 3595 3596 * g++ now unconditionally enables large file support when compiling 3597 32-bit code. 3598 * Support for the AddressSanitizer and UndefinedBehaviorSanitizer has 3599 been merged from LLVM. For the moment, this only works for 32-bit 3600 code on both SPARC and x86. 3601 * An initial port of the D runtime library has been completed on 3602 Solaris 11/x86. It requires the use of GNU as. Solaris 11/SPARC 3603 support is still work-in-progress. 3604 3605 Windows 3606 3607 * A C++ Microsoft ABI bitfield layout bug, [62]PR87137 has been 3608 fixed. A non-field declaration could cause the current bitfield 3609 allocation unit to be completed, incorrectly placing a following 3610 bitfield into a new allocation unit. The Microsoft ABI is selected 3611 for: 3612 + Mingw targets 3613 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 3614 option is specified, or __attribute__((ms_struct)) is used 3615 + SuperH targets when the -mhitachi option is specified, or 3616 __attribute__((renesas)) is used 3617 3618 Improvements for plugin authors 3619 3620 * GCC's diagnostic subsystem now has a way to logically group 3621 together related diagnostics, auto_diagnostic_group. Such 3622 diagnostics will be nested by the output of 3623 [63]-fdiagnostics-format=json. 3624 * GCC now has a set of [64]user experience guidelines for GCC, with 3625 information and advice on implementing new diagnostics. 3626 3627 Other significant improvements 3628 3629 * GCC's internal "selftest" suite now runs for C++ as well as C (in 3630 debug builds of the compiler). 3631 3632 GCC 9.1 3633 3634 This is the [65]list of problem reports (PRs) from GCC's bug tracking 3635 system that are known to be fixed in the 9.1 release. This list might 3636 not be complete (that is, it is possible that some PRs that have been 3637 fixed are not listed here). 3638 3639 GCC 9.2 3640 3641 This is the [66]list of problem reports (PRs) from GCC's bug tracking 3642 system that are known to be fixed in the 9.2 release. This list might 3643 not be complete (that is, it is possible that some PRs that have been 3644 fixed are not listed here). 3645 3646 GCC 9.3 3647 3648 This is the [67]list of problem reports (PRs) from GCC's bug tracking 3649 system that are known to be fixed in the 9.3 release. This list might 3650 not be complete (that is, it is possible that some PRs that have been 3651 fixed are not listed here). 3652 3653 GCC 9.4 3654 3655 This is the [68]list of problem reports (PRs) from GCC's bug tracking 3656 system that are known to be fixed in the 9.4 release. This list might 3657 not be complete (that is, it is possible that some PRs that have been 3658 fixed are not listed here). 3659 3660 Target Specific Changes 3661 3662 AArch64 3663 3664 * The option -moutline-atomics has been added to aid deployment of 3665 the Large System Extensions (LSE) on GNU/Linux systems built with a 3666 baseline architecture targeting Armv8-A. When the option is 3667 specified code is emitted to detect the presence of LSE 3668 instructions at run time and use them for standard atomic 3669 operations. For more information please refer to the documentation. 3670 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 3671 options are -mcpu=a64fx and -mtune=a64fx respectively. In 3672 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 3673 tunes the code for the A64FX. This includes tuning the SVE code, 3674 although by default the code is still length-agnostic and so works 3675 for all SVE implementations. Adding -msve-vector-bits=512 makes the 3676 code specific to 512-bit SVE. 3677 3678 GCC 9.5 3679 3680 This is the [69]list of problem reports (PRs) from GCC's bug tracking 3681 system that are known to be fixed in the 9.5 release. This list might 3682 not be complete (that is, it is possible that some PRs that have been 3683 fixed are not listed here). 3684 3685 3686 For questions related to the use of GCC, please consult these web 3687 pages and the [70]GCC manuals. If that fails, the 3688 [71]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 3689 web pages and the development of GCC are welcome on our developer 3690 list at [72]gcc (a] gcc.gnu.org. All of [73]our lists have public 3691 archives. 3692 3693 Copyright (C) [74]Free Software Foundation, Inc. Verbatim copying and 3694 distribution of this entire article is permitted in any medium, 3695 provided this notice is preserved. 3696 3697 These pages are [75]maintained by the GCC team. Last modified 3698 2023-02-22. 3699 3700 References 3701 3702 1. http://gcc.gnu.org/gcc-9/porting_to.html 3703 2. http://gcc.gnu.org/onlinedocs/index.html#current 3704 3. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88469 3705 4. https://gcc.gnu.org/ml/gcc/2018-10/msg00139.html 3706 5. https://gcc.gnu.org/ml/gcc/2019-04/msg00023.html 3707 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90920 3708 7. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-frepo 3709 8. https://gcc.gnu.org/PR90361 3710 9. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-GCC.html#Invoking-GCC 3711 10. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-flive-patching 3712 11. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-line-numbers 3713 12. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-labels 3714 13. 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https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fversion-loops-for-strides 3732 31. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-interchange 3733 32. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-unroll-and-jam 3734 33. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-ftree-loop-distribution 3735 34. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-Gcov.html#Invoking-Gcov 3736 35. https://www.openacc.org/ 3737 36. https://gcc.gnu.org/wiki/OpenACC/Implementation%20Status#status-9 3738 37. https://www.openmp.org/specifications/ 3739 38. https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00628.html 3740 39. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Vector-Extensions.html#index-_005f_005fbuiltin_005fconvertvector 3741 40. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Waddress-of-packed-member 3742 41. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Warray-bounds 3743 42. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wattribute-alias 3744 43. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wformat-overflow 3745 44. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wformat-truncation 3746 45. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wmissing-attributes 3747 46. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wstringop-truncation 3748 47. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wabsolute-value 3749 48. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wdeprecated-copy 3750 49. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Winit-list-lifetime 3751 50. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wredundant-move 3752 51. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wpessimizing-move 3753 52. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wclass-conversion 3754 53. http://gcc.gnu.org/projects/cxx-status.html#cxx2a 3755 54. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wformat 3756 55. https://github.com/oneapi-src/oneTBB 3757 56. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gfortran/Fortran-Dialect-Options.html#index-fdec-include 3758 57. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gfortran/Fortran-Dialect-Options.html#index-fdec 3759 58. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gfortran/BUILTIN-directive.html#BUILTIN-directive 3760 59. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/jit/topics/contexts.html#gcc_jit_context_add_driver_option 3761 60. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Instrumentation-Options.html#index-fstack-protector 3762 61. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/AArch64-Options.html#AArch64-Options 3763 62. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137 3764 63. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 3765 64. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gccint/User-Experience-Guidelines.html 3766 65. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=9.0 3767 66. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=9.2 3768 67. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=9.3 3769 68. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=9.4 3770 69. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=9.5 3771 70. https://gcc.gnu.org/onlinedocs/ 3772 71. mailto:gcc-help (a] gcc.gnu.org 3773 72. mailto:gcc (a] gcc.gnu.org 3774 73. https://gcc.gnu.org/lists.html 3775 74. https://www.fsf.org/ 3776 75. https://gcc.gnu.org/about.html 3777 ====================================================================== 3778 http://gcc.gnu.org/gcc-8/index.html 3779 3780 GCC 8 Release Series 3781 3782 (This release series is no longer supported.) 3783 3784 May 14, 2021 3785 3786 The [1]GNU project and the GCC developers are pleased to announce the 3787 release of GCC 8.5. 3788 3789 This release is a bug-fix release, containing fixes for regressions in 3790 GCC 8.4 relative to previous releases of GCC. 3791 3792 Release History 3793 3794 GCC 8.5 3795 May 14, 2021 ([2]changes, [3]documentation) 3796 3797 GCC 8.4 3798 Mar 4, 2020 ([4]changes, [5]documentation) 3799 3800 GCC 8.3 3801 Feb 22, 2019 ([6]changes, [7]documentation) 3802 3803 GCC 8.2 3804 Jul 26, 2018 ([8]changes, [9]documentation) 3805 3806 GCC 8.1 3807 May 2, 2018 ([10]changes, [11]documentation) 3808 3809 References and Acknowledgements 3810 3811 GCC used to stand for the GNU C Compiler, but since the compiler 3812 supports several other languages aside from C, it now stands for the 3813 GNU Compiler Collection. 3814 3815 A list of [12]successful builds is updated as new information becomes 3816 available. 3817 3818 The GCC developers would like to thank the numerous people that have 3819 contributed new features, improvements, bug fixes, and other changes as 3820 well as test results to GCC. This [13]amazing group of volunteers is 3821 what makes GCC successful. 3822 3823 For additional information about GCC please refer to the [14]GCC 3824 project web site or contact the [15]GCC development mailing list. 3825 3826 To obtain GCC please use [16]our mirror sites or [17]our version 3827 control system. 3828 3829 3830 For questions related to the use of GCC, please consult these web 3831 pages and the [18]GCC manuals. If that fails, the 3832 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 3833 web pages and the development of GCC are welcome on our developer 3834 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 3835 archives. 3836 3837 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 3838 distribution of this entire article is permitted in any medium, 3839 provided this notice is preserved. 3840 3841 These pages are [23]maintained by the GCC team. Last modified 3842 2022-10-26. 3843 3844 References 3845 3846 1. http://www.gnu.org/ 3847 2. http://gcc.gnu.org/gcc-8/changes.html 3848 3. http://gcc.gnu.org/onlinedocs/8.5.0/ 3849 4. http://gcc.gnu.org/gcc-8/changes.html 3850 5. http://gcc.gnu.org/onlinedocs/8.4.0/ 3851 6. http://gcc.gnu.org/gcc-8/changes.html 3852 7. http://gcc.gnu.org/onlinedocs/8.3.0/ 3853 8. http://gcc.gnu.org/gcc-8/changes.html 3854 9. http://gcc.gnu.org/onlinedocs/8.2.0/ 3855 10. http://gcc.gnu.org/gcc-8/changes.html 3856 11. http://gcc.gnu.org/onlinedocs/8.1.0/ 3857 12. http://gcc.gnu.org/gcc-8/buildstat.html 3858 13. http://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Contributors.html 3859 14. http://gcc.gnu.org/index.html 3860 15. mailto:gcc (a] gcc.gnu.org 3861 16. http://gcc.gnu.org/mirrors.html 3862 17. http://gcc.gnu.org/git.html 3863 18. https://gcc.gnu.org/onlinedocs/ 3864 19. mailto:gcc-help (a] gcc.gnu.org 3865 20. mailto:gcc (a] gcc.gnu.org 3866 21. https://gcc.gnu.org/lists.html 3867 22. https://www.fsf.org/ 3868 23. https://gcc.gnu.org/about.html 3869 ====================================================================== 3870 http://gcc.gnu.org/gcc-8/changes.html 3871 3872 GCC 8 Release Series 3873 Changes, New Features, and Fixes 3874 3875 This page is a "brief" summary of some of the huge number of 3876 improvements in GCC 8. You may also want to check out our [1]Porting to 3877 GCC 8 page and the [2]full GCC documentation. 3878 3879 Caveats 3880 3881 * Support for the obsolete SDB/coff debug info format has been 3882 removed. The option -gcoff no longer does anything. 3883 * The Cilk+ extensions to the C and C++ languages have been removed. 3884 * The MPX extensions to the C and C++ languages have been deprecated 3885 and will be removed in a future release. 3886 * The extension allowing arithmetic on std::atomic<void*> and types 3887 like std::atomic<R(*)()> has been deprecated. 3888 * The non-standard C++0x std::copy_exception function was removed. 3889 std::make_exception_ptr should be used instead. 3890 * Support for the powerpc*-*-*spe* target ports which have been 3891 recently unmaintained and untested in GCC has been declared 3892 obsolete in GCC 8 as [3]announced. Unless there is activity to 3893 revive them, the next release of GCC will have their sources 3894 permanently removed. 3895 3896 General Improvements 3897 3898 * Inter-procedural optimization improvements: 3899 + Reworked run-time estimation metrics leading to more realistic 3900 guesses driving inliner and cloning heuristics. 3901 + The ipa-pure-const pass is extended to propagate the malloc 3902 attribute, and the corresponding warning option 3903 -Wsuggest-attribute=malloc emits a diagnostic for functions 3904 which can be annotated with the malloc attribute. 3905 * Profile driven optimization improvements: 3906 + New infrastructure for representing profiles (both statically 3907 guessed and profile feedback) which allows propagation of 3908 additional information about the reliability of the profile. 3909 + A number of improvements in the profile updating code solving 3910 problems found by new verification code. 3911 + Static detection of code which is not executed in a valid run 3912 of the program. This includes paths which trigger undefined 3913 behavior as well as calls to functions declared with the cold 3914 attribute. Newly the noreturn attribute does not imply all 3915 effects of cold to differentiate between exit (which is 3916 noreturn) and abort (which is in addition not executed in 3917 valid runs). 3918 + -freorder-blocks-and-partition, a pass splitting function 3919 bodies into hot and cold regions, is now enabled by default at 3920 -O2 and higher for x86 and x86-64. 3921 * Link-time optimization improvements: 3922 + We have significantly improved debug information on ELF 3923 targets using DWARF by properly preserving language-specific 3924 information. This allows for example the libstdc++ 3925 pretty-printers to work with LTO optimized executables. 3926 * A new option -fcf-protection=[full|branch|return|none] is 3927 introduced to perform code instrumentation to increase program 3928 security by checking that target addresses of control-flow transfer 3929 instructions (such as indirect function call, function return, 3930 indirect jump) are valid. Currently the instrumentation is 3931 supported on x86 GNU/Linux targets only. See the user guide for 3932 further information about the option syntax and section "New 3933 Targets and Target Specific Improvements" for IA-32/x86-64 for more 3934 details. 3935 * The -gcolumn-info option is now enabled by default. It includes 3936 column information in addition to just filenames and line numbers 3937 in DWARF debugging information. 3938 * The polyhedral-based loop nest optimization pass 3939 -floop-nest-optimize has been overhauled. It's still considered 3940 experimental and may not result in any runtime improvements. 3941 * Two new classical loop nest optimization passes have been added. 3942 -floop-unroll-and-jam performs outer loop unrolling and fusing of 3943 the inner loop copies. -floop-interchange exchanges loops in a loop 3944 nest to improve data locality. Both passes are enabled by default 3945 at -O3 and above. 3946 * The classic loop nest optimization pass -ftree-loop-distribution 3947 has been improved and enabled by default at -O3 and above. It 3948 supports loop nest distribution in some restricted scenarios; it 3949 also supports cancellable innermost loop distribution with loop 3950 versioning under run-time alias checks. 3951 * The new option -fstack-clash-protection causes the compiler to 3952 insert probes whenever stack space is allocated statically or 3953 dynamically to reliably detect stack overflows and thus mitigate 3954 the attack vector that relies on jumping over a stack guard page as 3955 provided by the operating system. 3956 * A new pragma GCC unroll has been implemented in the C family of 3957 languages, as well as Fortran and Ada, so as to make it possible 3958 for the user to have a finer-grained control over the loop 3959 unrolling optimization. 3960 * GCC has been enhanced to detect more instances of meaningless or 3961 mutually exclusive attribute specifications and handle such 3962 conflicts more consistently. Mutually exclusive attribute 3963 specifications are ignored with a warning regardless of whether 3964 they appear on the same declaration or on distinct declarations of 3965 the same entity. For example, because the noreturn attribute on the 3966 second declaration below is mutually exclusive with the malloc 3967 attribute on the first, it is ignored and a warning is issued. 3968 > 3969 void* __attribute__ ((malloc)) f (unsigned); 3970 void* __attribute__ ((noreturn)) f (unsigned); 3971 3972 warning: ignoring attribute 'noreturn' because it conflicts with attribute 3973 'malloc' [-Wattributes] 3974 * The gcov tool can distinguish functions that begin on a same line 3975 in a source file. This can be a different template instantiation or 3976 a class constructor: 3977 3978 File 'ins.C' 3979 Lines executed:100.00% of 8 3980 Creating 'ins.C.gcov' 3981 3982 -: 0:Source:ins.C 3983 -: 0:Graph:ins.gcno 3984 -: 0:Data:ins.gcda 3985 -: 0:Runs:1 3986 -: 0:Programs:1 3987 -: 1:template<class T> 3988 -: 2:class Foo 3989 -: 3:{ 3990 -: 4: public: 3991 2: 5: Foo(): b (1000) {} 3992 ------------------ 3993 Foo<char>::Foo(): 3994 1: 5: Foo(): b (1000) {} 3995 ------------------ 3996 Foo<int>::Foo(): 3997 1: 5: Foo(): b (1000) {} 3998 ------------------ 3999 2: 6: void inc () { b++; } 4000 ------------------ 4001 Foo<char>::inc(): 4002 1: 6: void inc () { b++; } 4003 ------------------ 4004 Foo<int>::inc(): 4005 1: 6: void inc () { b++; } 4006 ------------------ 4007 -: 7: 4008 -: 8: private: 4009 -: 9: int b; 4010 -: 10:}; 4011 -: 11: 4012 1: 12:int main(int argc, char **argv) 4013 -: 13:{ 4014 1: 14: Foo<int> a; 4015 1: 15: Foo<char> b; 4016 -: 16: 4017 1: 17: a.inc (); 4018 1: 18: b.inc (); 4019 1: 19:} 4020 4021 * The gcov tool has more accurate numbers for execution of lines in a 4022 source file. 4023 * The gcov tool can use TERM colors to provide more readable output. 4024 * AddressSanitizer gained a new pair of sanitization options, 4025 -fsanitize=pointer-compare and -fsanitize=pointer-subtract, which 4026 warn about subtraction (or comparison) of pointers that point to a 4027 different memory object: 4028 4029 int 4030 main () 4031 { 4032 /* Heap allocated memory. */ 4033 char *heap1 = (char *)__builtin_malloc (42); 4034 char *heap2 = (char *)__builtin_malloc (42); 4035 if (heap1 > heap2) 4036 return 1; 4037 4038 return 0; 4039 } 4040 4041 ==17465==ERROR: AddressSanitizer: invalid-pointer-pair: 0x604000000010 0x6040000 4042 00050 4043 #0 0x40070f in main /tmp/pointer-compare.c:7 4044 #1 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 4045 #2 0x400629 in _start (/tmp/a.out+0x400629) 4046 4047 0x604000000010 is located 0 bytes inside of 42-byte region [0x604000000010,0x604 4048 00000003a) 4049 allocated by thread T0 here: 4050 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 4051 _malloc_linux.cc:86 4052 #1 0x4006ea in main /tmp/pointer-compare.c:5 4053 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 4054 4055 0x604000000050 is located 0 bytes inside of 42-byte region [0x604000000050,0x604 4056 00000007a) 4057 allocated by thread T0 here: 4058 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 4059 _malloc_linux.cc:86 4060 #1 0x4006f8 in main /tmp/pointer-compare.c:6 4061 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 4062 4063 SUMMARY: AddressSanitizer: invalid-pointer-pair /tmp/pointer-compare.c:7 in main 4064 4065 * The store merging pass has been enhanced to handle bit-fields and 4066 not just constant stores, but also data copying from adjacent 4067 memory locations into other adjacent memory locations, including 4068 bitwise logical operations on the data. The pass can also handle 4069 byte swapping into memory locations. 4070 * The undefined behavior sanitizer gained two new options included in 4071 -fsanitize=undefined: -fsanitize=builtin which diagnoses at run 4072 time invalid arguments to __builtin_clz or __builtin_ctz prefixed 4073 builtins, and -fsanitize=pointer-overflow which performs cheap run 4074 time tests for pointer wrapping. 4075 * A new attribute no_sanitize can be applied to functions to instruct 4076 the compiler not to do sanitization of the options provided as 4077 arguments to the attribute. Acceptable values for no_sanitize match 4078 those acceptable by the -fsanitize command-line option. 4079 4080 void __attribute__ ((no_sanitize ("alignment", "object-size"))) 4081 f () { /* Do something. */; } 4082 4083 New Languages and Language specific improvements 4084 4085 Ada 4086 4087 * For its internal exception handling used on the host for error 4088 recovery in the front-end, the compiler now relies on the native 4089 exception handling mechanism of the host platform, which should be 4090 more efficient than the former mechanism. 4091 4092 BRIG (HSAIL) 4093 4094 In this release cycle, the focus for the BRIGFE was on stabilization 4095 and performance improvements. Also a couple of completely new features 4096 were added. 4097 * Improved support for function and module scope group segment 4098 variables. PRM specs define function and module scope group segment 4099 variables as an experimental feature. However, PRM test suite uses 4100 them. Now group segment is handled by separate book keeping of 4101 module scope and function (kernel) offsets. Each function has a 4102 "frame" in the group segment offset to which is given as an 4103 argument, similar to traditional call stack frame handling. 4104 * Reduce the number of type conversions due to the untyped HSAIL 4105 registers. Instead of always representing the HSAIL's untyped 4106 registers as unsigned int, the gccbrig now pre-analyzes the BRIG 4107 code and builds the register variables as a type used the most when 4108 storing or reading data to/from each register. This reduces the 4109 number of total casts which cannot be always optimized away. 4110 * Support for BRIG_KIND_NONE directives. 4111 * Made -O3 the default optimization level for BRIGFE. 4112 * Fixed illegal addresses generated from address expressions which 4113 refer only to offset 0. 4114 * Fixed a bug with reg+offset addressing on 32b segments. In 'large' 4115 mode, the offset is treated as 32-bit unless it's in global, 4116 read-only or kernarg address space. 4117 * Fixed a crash caused sometimes by calls with more than 4 arguments. 4118 * Fixed a mis-execution issue with kernels that have both unexpanded 4119 ID functions and calls to subfunctions. 4120 * Treat HSAIL barrier builtins as setjmp/longjump style functions to 4121 avoid illegal optimizations. 4122 * Ensure per WI copies of private variables are aligned correctly. 4123 * libhsail-rt: Assume the host runtime allocates the work group 4124 memory. 4125 4126 C family 4127 4128 * New command-line options have been added for the C and C++ 4129 compilers: 4130 + [4]-Wmultistatement-macros warns about unsafe macros expanding 4131 to multiple statements used as a body of a statement such as 4132 if, else, while, switch, or for. 4133 + [5]-Wstringop-truncation warns for calls to bounded string 4134 manipulation functions such as strncat, strncpy, and stpncpy 4135 that might either truncate the copied string or leave the 4136 destination unchanged. For example, the following call to 4137 strncat is diagnosed because it appends just three of the four 4138 characters from the source string. 4139 void append (char *buf, size_t bufsize) 4140 { 4141 strncat (buf, ".txt", 3); 4142 } 4143 warning: 'strncat' output truncated copying 3 bytes from a string of length 4 [- 4144 Wstringop-truncation] 4145 Similarly, in the following example, the call to strncpy 4146 specifies the size of the destination buffer as the bound. If 4147 the length of the source string is equal to or greater than 4148 this size the result of the copy will not be NUL-terminated. 4149 Therefore, the call is also diagnosed. To avoid the warning, 4150 specify sizeof buf - 1 as the bound and set the last element 4151 of the buffer to NUL. 4152 void copy (const char *s) 4153 { 4154 char buf[80]; 4155 strncpy (buf, s, sizeof buf); 4156 ... 4157 } 4158 warning: 'strncpy' specified bound 80 equals destination size [-Wstringop-trunca 4159 tion] 4160 The -Wstringop-truncation option is included in -Wall. 4161 Note that due to GCC bug [6]82944, defining strncat, strncpy, 4162 or stpncpy as a macro in a system header as some 4163 implementations do, suppresses the warning. 4164 + [7]-Wif-not-aligned controls warnings issued in response to 4165 invalid uses of objects declared with attribute 4166 [8]warn_if_not_aligned. 4167 The -Wif-not-aligned option is included in -Wall. 4168 + [9]-Wmissing-attributes warns when a declaration of a function 4169 is missing one or more attributes that a related function is 4170 declared with and whose absence may adversely affect the 4171 correctness or efficiency of generated code. For example, in 4172 C++, the warning is issued when an explicit specialization of 4173 a primary template declared with attribute alloc_align, 4174 alloc_size, assume_aligned, format, format_arg, malloc, or 4175 nonnull is declared without it. Attributes deprecated, error, 4176 and warning suppress the warning. 4177 The -Wmissing-attributes option is included in -Wall. 4178 + [10]-Wpacked-not-aligned warns when a struct or union declared 4179 with attribute packed defines a member with an explicitly 4180 specified alignment greater than 1. Such a member will wind up 4181 under-aligned. For example, a warning will be issued for the 4182 definition of struct A in the following: 4183 struct __attribute__ ((aligned (8))) 4184 S8 { char a[8]; }; 4185 4186 struct __attribute__ ((packed)) A 4187 { 4188 struct S8 s8; 4189 }; 4190 warning: alignment 1 of 'struct S' is less than 8 [-Wpacked-not-aligned] 4191 The -Wpacked-not-aligned option is included in -Wall. 4192 + -Wcast-function-type warns when a function pointer is cast to 4193 an incompatible function pointer. This warning is enabled by 4194 -Wextra. 4195 + -Wsizeof-pointer-div warns for suspicious divisions of the 4196 size of a pointer by the size of the elements it points to, 4197 which looks like the usual way to compute the array size but 4198 won't work out correctly with pointers. This warning is 4199 enabled by -Wall. 4200 + -Wcast-align=strict warns whenever a pointer is cast such that 4201 the required alignment of the target is increased. For 4202 example, warn if a char * is cast to an int * regardless of 4203 the target machine. 4204 + -fprofile-abs-path creates absolute path names in the .gcno 4205 files. This allows gcov to find the correct sources in 4206 projects where compilations occur with different working 4207 directories. 4208 * -fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer and 4209 signed integer overflow is now undefined by default at all 4210 optimization levels. Using -fsanitize=signed-integer-overflow is 4211 now the preferred way to audit code, -Wstrict-overflow is 4212 deprecated. 4213 * The [11]-Warray-bounds option has been improved to detect more 4214 instances of out-of-bounds array indices and pointer offsets. For 4215 example, negative or excessive indices into flexible array members 4216 and string literals are detected. 4217 * The [12]-Wrestrict option introduced in GCC 7 has been enhanced to 4218 detect many more instances of overlapping accesses to objects via 4219 restrict-qualified arguments to standard memory and string 4220 manipulation functions such as memcpy and strcpy. For example, the 4221 strcpy call in the function below attempts to truncate the string 4222 by replacing its initial characters with the last four. However, 4223 because the function writes the terminating NUL into a[4], the 4224 copies overlap and the call is diagnosed. 4225 void f (void) 4226 { 4227 char a[] = "abcd1234"; 4228 strcpy (a, a + 4); 4229 ... 4230 } 4231 warning: 'strcpy' accessing 5 bytes at offsets 0 and 4 overlaps 1 byte at offset 4232 4 [-Wrestrict] 4233 The -Wrestrict option is included in -Wall. 4234 * Several optimizer enhancements have enabled improvements to the 4235 [13]-Wformat-overflow and [14]-Wformat-truncation options. The 4236 warnings detect more instances of buffer overflow and truncation 4237 than in GCC 7 and are better at avoiding certain kinds of false 4238 positives. 4239 * When reporting mismatching argument types at a function call, the C 4240 and C++ compilers now underline both the argument and the pertinent 4241 parameter in the declaration. 4242 $ gcc arg-type-mismatch.cc 4243 arg-type-mismatch.cc: In function 'int caller(int, int, float)': 4244 arg-type-mismatch.cc:5:24: error: invalid conversion from 'int' to 'const char*' 4245 [-fpermissive] 4246 return callee(first, second, third); 4247 ^~~~~~ 4248 arg-type-mismatch.cc:1:40: note: initializing argument 2 of 'int callee(int, c 4249 onst char*, float)' 4250 extern int callee(int one, const char *two, float three); 4251 ~~~~~~~~~~~~^~~ 4252 4253 * When reporting on unrecognized identifiers, the C and C++ compilers 4254 will now emit fix-it hints suggesting #include directives for 4255 various headers in the C and C++ standard libraries. 4256 $ gcc incomplete.c 4257 incomplete.c: In function 'test': 4258 incomplete.c:3:10: error: 'NULL' undeclared (first use in this function) 4259 return NULL; 4260 ^~~~ 4261 incomplete.c:3:10: note: 'NULL' is defined in header '<stddef.h>'; did you forge 4262 t to '#include <stddef.h>'? 4263 incomplete.c:1:1: 4264 +#include <stddef.h> 4265 const char *test(void) 4266 incomplete.c:3:10: 4267 return NULL; 4268 ^~~~ 4269 incomplete.c:3:10: note: each undeclared identifier is reported only once for ea 4270 ch function it appears in 4271 4272 $ gcc incomplete.cc 4273 incomplete.cc:1:6: error: 'string' in namespace 'std' does not name a type 4274 std::string s("hello world"); 4275 ^~~~~~ 4276 incomplete.cc:1:1: note: 'std::string' is defined in header '<string>'; did you 4277 forget to '#include <string>'? 4278 +#include <string> 4279 std::string s("hello world"); 4280 ^~~ 4281 4282 * The C and C++ compilers now use more intuitive locations when 4283 reporting on missing semicolons, and offer fix-it hints: 4284 $ gcc t.c 4285 t.c: In function 'test': 4286 t.c:3:12: error: expected ';' before '}' token 4287 return 42 4288 ^ 4289 ; 4290 } 4291 ~ 4292 4293 * When reporting on missing '}' and ')' tokens, the C and C++ 4294 compilers will now highlight the corresponding '{' and '(' token, 4295 issuing a 'note' if it's on a separate line: 4296 $ gcc unclosed.c 4297 unclosed.c: In function 'log_when_out_of_range': 4298 unclosed.c:12:50: error: expected ')' before '{' token 4299 && (temperature < MIN || temperature > MAX) { 4300 ^~ 4301 ) 4302 unclosed.c:11:6: note: to match this '(' 4303 if (logging_enabled && check_range () 4304 ^ 4305 4306 or highlighting it directly if it's on the same line: 4307 $ gcc unclosed-2.c 4308 unclosed-2.c: In function 'test': 4309 unclosed-2.c:8:45: error: expected ')' before '{' token 4310 if (temperature < MIN || temperature > MAX { 4311 ~ ^~ 4312 ) 4313 4314 They will also emit fix-it hints. 4315 4316 C++ 4317 4318 * GCC 8 (-fabi-version=12) has a couple of corrections to the calling 4319 convention, which changes the ABI for some uncommon code: 4320 + Passing an empty class as an argument now takes up no space on 4321 x86_64, as required by the psABI. 4322 + Passing or returning a class with only deleted copy and move 4323 constructors now uses the same calling convention as a class 4324 with a non-trivial copy or move constructor. This only affects 4325 C++17 mode, as in earlier standards passing or returning such 4326 a class was impossible. 4327 + WARNING: In GCC 8.1 the second change mistakenly also affects 4328 classes with a deleted copy constructor and defaulted trivial 4329 move constructor (bug [15]c++/86094). This issue is fixed in 4330 GCC 8.2 (-fabi-version=13). 4331 You can test whether these changes affect your code with -Wabi=11 4332 (or -Wabi=12 in GCC 8.2 for the third issue); if these changes are 4333 problematic for your project, the GCC 7 ABI can be selected with 4334 -fabi-version=11. 4335 * The value of the C++11 alignof operator has been corrected to match 4336 C _Alignof (minimum alignment) rather than GNU __alignof__ 4337 (preferred alignment); on ia32 targets this means that 4338 alignof(double) is now 4 rather than 8. Code that wants the 4339 preferred alignment should use __alignof__ instead. 4340 * New command-line options have been added for the C++ compiler to 4341 control warnings: 4342 + [16]-Wclass-memaccess warns when objects of non-trivial class 4343 types are manipulated in potentially unsafe ways by raw memory 4344 functions such as memcpy, or realloc. The warning helps detect 4345 calls that bypass user-defined constructors or copy-assignment 4346 operators, corrupt virtual table pointers, data members of 4347 const-qualified types or references, or member pointers. The 4348 warning also detects calls that would bypass access controls 4349 to data members. For example, a call such as: 4350 memcpy (&std::cout, &std::cerr, sizeof std::cout); 4351 results in 4352 warning: 'void* memcpy(void*, const void*, long unsigned int)' writing t 4353 o an object of type 'std::ostream' {aka 'class std::basic_ostream<char>'} with n 4354 o trivial copy-assignment [-Wclass-memaccess] 4355 The -Wclass-memaccess option is included in -Wall. 4356 * The C++ front end has experimental support for some of the upcoming 4357 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 4358 including designated initializers, default member initializers for 4359 bit-fields, __VA_OPT__ (except that #__VA_OPT__ is unsupported), 4360 lambda [=, this] captures, etc. For a full list of new features, 4361 see [17]the C++ status page. 4362 * When reporting on attempts to access private fields of a class or 4363 struct, the C++ compiler will now offer fix-it hints showing how to 4364 use an accessor function to get at the field in question, if one 4365 exists. 4366 $ gcc accessor.cc 4367 accessor.cc: In function 'void test(foo*)': 4368 accessor.cc:12:12: error: 'double foo::m_ratio' is private within this context 4369 if (ptr->m_ratio >= 0.5) 4370 ^~~~~~~ 4371 accessor.cc:7:10: note: declared private here 4372 double m_ratio; 4373 ^~~~~~~ 4374 accessor.cc:12:12: note: field 'double foo::m_ratio' can be accessed via 'double 4375 foo::get_ratio() const' 4376 if (ptr->m_ratio >= 0.5) 4377 ^~~~~~~ 4378 get_ratio() 4379 4380 * The C++ compiler can now give you a hint if you use a macro before 4381 it was defined (e.g. if you mess up the order of your #include 4382 directives): 4383 $ gcc ordering.cc 4384 ordering.cc:2:24: error: expected ';' at end of member declaration 4385 virtual void clone() const OVERRIDE { } 4386 ^~~~~ 4387 ; 4388 ordering.cc:2:30: error: 'OVERRIDE' does not name a type 4389 virtual void clone() const OVERRIDE { } 4390 ^~~~~~~~ 4391 ordering.cc:2:30: note: the macro 'OVERRIDE' had not yet been defined 4392 In file included from ordering.cc:5: 4393 c++11-compat.h:2: note: it was later defined here 4394 #define OVERRIDE override 4395 4396 4397 * The -Wold-style-cast diagnostic can now emit fix-it hints telling 4398 you when you can use a static_cast, const_cast, or 4399 reinterpret_cast. 4400 $ gcc -c old-style-cast-fixits.cc -Wold-style-cast 4401 old-style-cast-fixits.cc: In function 'void test(void*)': 4402 old-style-cast-fixits.cc:5:19: warning: use of old-style cast to 'struct foo*' [ 4403 -Wold-style-cast] 4404 foo *f = (foo *)ptr; 4405 ^~~ 4406 ---------- 4407 static_cast<foo *> (ptr) 4408 4409 * When reporting on problems within extern "C" linkage 4410 specifications, the C++ compiler will now display the location of 4411 the start of the extern "C". 4412 $ gcc -c extern-c.cc 4413 extern-c.cc:3:1: error: template with C linkage 4414 template <typename T> void test (void); 4415 ^~~~~~~~ 4416 In file included from extern-c.cc:1: 4417 unclosed.h:1:1: note: 'extern "C"' linkage started here 4418 extern "C" { 4419 ^~~~~~~~~~ 4420 extern-c.cc:3:39: error: expected '}' at end of input 4421 template <typename T> void test (void); 4422 ^ 4423 In file included from extern-c.cc:1: 4424 unclosed.h:1:12: note: to match this '{' 4425 extern "C" { 4426 ^ 4427 4428 * When reporting on mismatching template types, the C++ compiler will 4429 now use color to highlight the mismatching parts of the template, 4430 and will elide the parameters that are common between two 4431 mismatching templates, printing [...] instead: 4432 $ gcc templates.cc 4433 templates.cc: In function 'void test()': 4434 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 4435 e>' to 'vector<int>' 4436 fn_1(vector<double> ()); 4437 ^~~~~~~~~~~~~~~~~ 4438 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<[...] 4439 ,double>' to 'map<[...],int>' 4440 fn_2(map<int, double>()); 4441 ^~~~~~~~~~~~~~~~~~ 4442 4443 Those [...] elided parameters can be seen using -fno-elide-type: 4444 $ gcc templates.cc -fno-elide-type 4445 templates.cc: In function 'void test()': 4446 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 4447 e>' to 'vector<int>' 4448 fn_1(vector<double> ()); 4449 ^~~~~~~~~~~~~~~~~ 4450 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<int,d 4451 ouble>' to 'map<int,int>' 4452 fn_2(map<int, double>()); 4453 ^~~~~~~~~~~~~~~~~~ 4454 4455 The C++ compiler has also gained an option 4456 -fdiagnostics-show-template-tree which visualizes such mismatching 4457 templates in a hierarchical form: 4458 $ gcc templates-2.cc -fdiagnostics-show-template-tree 4459 templates-2.cc: In function 'void test()': 4460 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 4461 ble>' to 'vector<int>' 4462 vector< 4463 [double != int]> 4464 fn_1(vector<double> ()); 4465 ^~~~~~~~~~~~~~~~~ 4466 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 4467 ctor<double> >()' from 'map<map<[...],vector<double>>,vector<double>>' to 'map<m 4468 ap<[...],vector<float>>,vector<float>>' 4469 map< 4470 map< 4471 [...], 4472 vector< 4473 [double != float]>>, 4474 vector< 4475 [double != float]>> 4476 fn_2(map<map<int, vector<double>>, vector<double>> ()); 4477 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4478 4479 which again works with -fno-elide-type: 4480 $ gcc templates-2.cc -fdiagnostics-show-template-tree -fno-elide-type 4481 templates-2.cc: In function 'void test()': 4482 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 4483 ble>' to 'vector<int>' 4484 vector< 4485 [double != int]> 4486 fn_1(vector<double> ()); 4487 ^~~~~~~~~~~~~~~~~ 4488 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 4489 ctor<double> >()' from 'map<map<int,vector<double>>,vector<double>>' to 'map<map 4490 <int,vector<float>>,vector<float>>' 4491 map< 4492 map< 4493 int, 4494 vector< 4495 [double != float]>>, 4496 vector< 4497 [double != float]>> 4498 fn_2(map<map<int, vector<double>>, vector<double>> ()); 4499 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4500 4501 * Flowing off the end of a non-void function is considered 4502 unreachable and may be subject to optimization on that basis. As a 4503 result of this change, -Wreturn-type warnings are enabled by 4504 default for C++. 4505 4506 Runtime Library (libstdc++) 4507 4508 * Improved experimental support for C++17, including the following 4509 features: 4510 + Deduction guides to support class template argument deduction. 4511 + std::filesystem implementation. 4512 + std::char_traits<char> and std::char_traits<wchar_t> are 4513 usable in constant expressions. 4514 + std::to_chars and std::from_chars (for integers only, not for 4515 floating point types). 4516 * Experimental support for C++2a: std::to_address (thanks to Glen 4517 Fernandes) and std::endian. 4518 * On GNU/Linux, std::random_device::entropy() accesses the kernel's 4519 entropy count for the random device, if known (thanks to Xi 4520 Ruoyao). 4521 * Support for std::experimental::source_location. 4522 * AddressSanitizer integration for std::vector, detecting 4523 out-of-range accesses to the unused capacity of a vector. 4524 * Extensions __gnu_cxx::airy_ai and __gnu_cxx::airy_bi added to the 4525 Mathematical Special Functions. 4526 4527 Fortran 4528 4529 * The main version of libfortran has been changed to 5. 4530 * Parameterized derived types, a major feature of Fortran 2003, have 4531 been implemented. 4532 * Partial support is provided for Fortran 2018 teams, which are 4533 hierarchical subsets of images that execute independently of other 4534 image subsets. 4535 * The maximum rank for arrays has been increased to 15, conforming to 4536 the Fortran 2008 standard. 4537 * Transformational intrinsics are now fully supported in 4538 initialization expressions. 4539 * New flag -fc-prototypes to write C prototypes for BIND(C) 4540 procedures and variables. 4541 * If -fmax-stack-var-size is honored if given together with -Ofast, 4542 -fstack-arrays is no longer set in that case. 4543 * New options -fdefault-real-16 and -fdefault-real-10 to control the 4544 default kind of REAL variables. 4545 * A warning is now issued if an array subscript inside a DO loop 4546 could lead to an out-of-bounds-access. The new option 4547 -Wdo-subscript, enabled by -Wextra, warns about this even if the 4548 compiler can not prove that the code will be executed. 4549 * The Fortran front end now attempts to interchange loops if it is 4550 deemed profitable. So far, this is restricted to FORALL and DO 4551 CONCURRENT statements with multiple indices. This behavior be 4552 controlled with the new flag -ffrontend-loop-interchange, which is 4553 enabled with optimization by default. The 4554 -Wfrontend-loop-interchange option warns about such occurrences. 4555 * When an actual argument contains too few elements for a dummy 4556 argument, an error is now issued. The -std=legacy option can be 4557 used to still compile such code. 4558 * The RECL= argument to OPEN and INQUIRE statements now allows 64-bit 4559 integers, making records larger than 2GiB possible. 4560 * The GFORTRAN_DEFAULT_RECL environment variable no longer has any 4561 effect. The record length for preconnected units is now larger than 4562 any practical limit, same as for sequential access units opened 4563 without an explicit RECL= specifier. 4564 * Character variables longer than HUGE(0) elements are now possible 4565 on 64-bit targets. Note that this changes the procedure call ABI 4566 for all procedures with character arguments on 64-bit targets, as 4567 the type of the hidden character length argument has changed. The 4568 hidden character length argument is now of type INTEGER(C_SIZE_T). 4569 * Partial support is provided for Fortran 2018 teams, which are 4570 hierarchical subsets of images that execute independently of other 4571 image subsets. 4572 4573 Go 4574 4575 * GCC 8 provides a complete implementation of the Go 1.10.1 user 4576 packages. 4577 * The garbage collector is now fully concurrent. As before, values 4578 stored on the stack are scanned conservatively, but value stored in 4579 the heap are scanned precisely. 4580 * Escape analysis is fully implemented and enabled by default in the 4581 Go front end. This significantly reduces the number of heap 4582 allocations by allocating values on the stack instead. 4583 4584 libgccjit 4585 4586 The libgccjit API gained four new entry points: 4587 * [18]gcc_jit_type_get_vector and 4588 * [19]gcc_jit_context_new_rvalue_from_vector for working with 4589 vectors, 4590 * [20]gcc_jit_type_get_aligned 4591 * [21]gcc_jit_function_get_address 4592 4593 The C code generated by [22]gcc_jit_context_dump_reproducer_to_file is 4594 now easier-to-read. 4595 4596 New Targets and Target Specific Improvements 4597 4598 AArch64 4599 4600 * The Armv8.4-A architecture is now supported. It can be used by 4601 specifying the -march=armv8.4-a option. 4602 * The Dot Product instructions are now supported as an optional 4603 extension to the Armv8.2-A architecture and newer and are mandatory 4604 on Armv8.4-A. The extension can be used by specifying the +dotprod 4605 architecture extension. E.g. -march=armv8.2-a+dotprod. 4606 * The Armv8-A +crypto extension has now been split into two 4607 extensions for finer grained control: 4608 + +aes which contains the Armv8-A AES crytographic instructions. 4609 + +sha2 which contains the Armv8-A SHA2 and SHA1 cryptographic 4610 instructions. 4611 Using +crypto will now enable these two extensions. 4612 * New Armv8.4-A FP16 Floating Point Multiplication Variant 4613 instructions have been added. These instructions are mandatory in 4614 Armv8.4-A but available as an optional extension to Armv8.2-A and 4615 Armv8.3-A. The new extension can be used by specifying the +fp16fml 4616 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 4617 the instructions can be enabled by specifying +fp16. 4618 * New cryptographic instructions have been added as optional 4619 extensions to Armv8.2-A and newer. These instructions can be 4620 enabled with: 4621 + +sha3 New SHA3 and SHA2 instructions from Armv8.4-A. This 4622 implies +sha2. 4623 + +sm4 New SM3 and SM4 instructions from Armv8.4-A. 4624 * The Scalable Vector Extension (SVE) is now supported as an optional 4625 extension to the Armv8.2-A architecture and newer. This support 4626 includes automatic vectorization with SVE instructions, but it does 4627 not yet include the SVE Arm C Language Extensions (ACLE). It can be 4628 enabled by specifying the +sve architecture extension (for example, 4629 -march=armv8.2-a+sve). By default, the generated code works with 4630 all vector lengths, but it can be made specific to N-bit vectors 4631 using -msve-vector-bits=N. 4632 * Support has been added for the following processors (GCC 4633 identifiers in parentheses): 4634 + Arm Cortex-A75 (cortex-a75). 4635 + Arm Cortex-A55 (cortex-a55). 4636 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 4637 (cortex-a75.cortex-a55). 4638 The GCC identifiers can be used as arguments to the -mcpu or -mtune 4639 options, for example: -mcpu=cortex-a75 or -mtune=cortex-a75 or as 4640 arguments to the equivalent target attributes and pragmas. 4641 4642 ARC 4643 4644 * Added support for: 4645 + Fast interrupts. 4646 + Naked functions. 4647 + aux variable attributes. 4648 + uncached type qualifier. 4649 + Secure functions via sjli instruction. 4650 * New exception handling implementation. 4651 * Revamped trampoline implementation. 4652 * Refactored small data feature implementation, controlled via the -G 4653 command-line option. 4654 * New support for reduced register set ARC architecture 4655 configurations, controlled via the -mrf16 command-line option. 4656 * Refurbished and improved support for zero overhead loops. 4657 Introduced -mlpc-width command-line option to control the width of 4658 the lp_count register. 4659 4660 ARM 4661 4662 * The -mfpu option now takes a new option setting of -mfpu=auto. When 4663 set to this the floating-point and SIMD settings are derived from 4664 the settings of the -mcpu or -march options. The internal CPU 4665 configurations have been updated with information about the 4666 permitted floating-point configurations supported. See the user 4667 guide for further information about the extended option syntax for 4668 controlling architectural extensions via the -march option. 4669 -mfpu=auto is now the default setting unless the compiler has been 4670 configured with an explicit --with-fpu option. 4671 * The -march and -mcpu options now accept optional extensions to the 4672 architecture or CPU option, allowing the user to enable or disable 4673 any such extensions supported by that architecture or CPU such as 4674 (but not limited to) floating-point and AdvancedSIMD. For example: 4675 the option -mcpu=cortex-a53+nofp will generate code for the 4676 Cortex-A53 processor with no floating-point support. This, in 4677 combination with the new -mfpu=auto option, provides a 4678 straightforward way of specifying a valid build target through a 4679 single -mcpu or -march option. The -mtune option accepts the same 4680 arguments as -mcpu but only the CPU name has an effect on tuning. 4681 The architecture extensions do not have any effect. For details of 4682 what extensions a particular architecture or CPU option supports 4683 please refer to the [23]documentation. 4684 * The -mstructure-size-boundary option has been deprecated and will 4685 be removed in a future release. 4686 * The default link behavior for Armv6 and Armv7-R targets has been 4687 changed to produce BE8 format when generating big-endian images. A 4688 new flag -mbe32 can be used to force the linker to produce legacy 4689 BE32 format images. There is no change of behavior for Armv6-M and 4690 other Armv7 or later targets: these already defaulted to BE8 4691 format. This change brings GCC into alignment with other compilers 4692 for the ARM architecture. 4693 * The Armv8-R architecture is now supported. It can be used by 4694 specifying the -march=armv8-r option. 4695 * The Armv8.3-A architecture is now supported. It can be used by 4696 specifying the -march=armv8.3-a option. 4697 * The Armv8.4-A architecture is now supported. It can be used by 4698 specifying the -march=armv8.4-a option. 4699 * The Dot Product instructions are now supported as an optional 4700 extension to the Armv8.2-A architecture and newer and are mandatory 4701 on Armv8.4-A. The extension can be used by specifying the +dotprod 4702 architecture extension. E.g. -march=armv8.2-a+dotprod. 4703 * Support for setting extensions and architectures using the GCC 4704 target pragma and attribute has been added. It can be used by 4705 specifying #pragma GCC target ("arch=..."), #pragma GCC target 4706 ("+extension"), __attribute__((target("arch=..."))) or 4707 __attribute__((target("+extension"))). 4708 * New Armv8.4-A FP16 Floating Point Multiplication Variant 4709 instructions have been added. These instructions are mandatory in 4710 Armv8.4-A but available as an optional extension to Armv8.2-A and 4711 Armv8.3-A. The new extension can be used by specifying the +fp16fml 4712 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 4713 the instructions can be enabled by specifying +fp16. 4714 * Support has been added for the following processors (GCC 4715 identifiers in parentheses): 4716 + Arm Cortex-A75 (cortex-a75). 4717 + Arm Cortex-A55 (cortex-a55). 4718 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 4719 (cortex-a75.cortex-a55). 4720 + Arm Cortex-R52 for Armv8-R (cortex-r52). 4721 The GCC identifiers can be used as arguments to the -mcpu or -mtune 4722 options, for example: -mcpu=cortex-a75 or -mtune=cortex-r52 or as 4723 arguments to the equivalent target attributes and pragmas. 4724 4725 AVR 4726 4727 * The AVR port now supports the following XMEGA-like devices: 4728 4729 ATtiny212, ATtiny214, ATtiny412, ATtiny414, ATtiny416, ATtiny417, 4730 ATtiny814, ATtiny816, ATtiny817, ATtiny1614, ATtiny1616, ATtiny1617, 4731 ATtiny3214, ATtiny3216, ATtiny3217 4732 The new devices are listed under [24]-mmcu=avrxmega3. 4733 + These devices see flash memory in the RAM address space, so 4734 that features like PROGMEM and __flash are not needed any more 4735 (as opposed to other AVR families for which read-only data 4736 will be located in RAM except special, non-standard features 4737 are used to locate and access such data). This requires that 4738 the compiler is used with Binutils 2.29 or newer so that 4739 [25]read-only data will be located in flash memory. 4740 + A new command-line option -mshort-calls is supported. This 4741 option is used internally for multilib selection of the 4742 avrxmega3 variants. It is not an optimization option. Do not 4743 set it by hand. 4744 * The compiler now generates [26]efficient interrupt service routine 4745 (ISR) prologues and epilogues. This is achieved by using the new 4746 [27]AVR pseudo instruction __gcc_isr which is supported and 4747 resolved by the GNU assembler. 4748 + As the __gcc_isr pseudo-instruction will be resolved by the 4749 assembler, inline assembly is transparent to the process. This 4750 means that when inline assembly uses an instruction like INC 4751 that clobbers the condition code, then the assembler will 4752 detect this and generate an appropriate ISR prologue / 4753 epilogue chunk to save / restore SREG as needed. 4754 + A new command-line option -mno-gas-isr-prologues disables the 4755 generation of the __gcc_isr pseudo instruction. Any non-naked 4756 ISR will save and restore SREG, tmp_reg and zero_reg, no 4757 matter whether the respective register is clobbered or used. 4758 + The feature is turned on per default for all optimization 4759 levels except for -O0 and -Og. It is explicitly enabled by 4760 means of option -mgas-isr-prologues. 4761 + Support has been added for a new [28]AVR function attribute 4762 no_gccisr. It can be used to disable __gcc_isr pseudo 4763 instruction generation for individual ISRs. 4764 + This optimization is only available if GCC is configured with 4765 GNU Binutils 2.29 or newer; or at least with a version of 4766 Binutils that implements feature [29]PR21683. 4767 * The compiler no more saves / restores registers in main; the effect 4768 is the same as if attribute OS_task was specified for main. This 4769 optimization can be switched off by the new command-line option 4770 -mno-main-is-OS_task. 4771 4772 IA-32/x86-64 4773 4774 * The x86 port now supports the naked function attribute. 4775 * Better tuning for znver1 and Intel Core based CPUs. 4776 * Vectorization cost metrics has been reworked leading to significant 4777 improvements on some benchmarks. 4778 * GCC now supports the Intel CPU named Cannonlake through 4779 -march=cannonlake. The switch enables the AVX512VBMI, AVX512IFMA 4780 and SHA ISA extensions. 4781 * GCC now supports the Intel CPU named Icelake through 4782 -march=icelake. The switch enables the AVX512VNNI, GFNI, VAES, 4783 AVX512VBMI2, VPCLMULQDQ, AVX512BITALG, RDPID and AVX512VPOPCNTDQ 4784 ISA extensions. 4785 * GCC now supports the Intel Control-flow Enforcement Technology 4786 (CET) extension through -fcf-protection option. 4787 4788 NDS32 4789 4790 * New command-line options -mext-perf, -mext-perf2, and -mext-string 4791 have been added for performance extension instructions. 4792 4793 Nios II 4794 4795 * The Nios II back end has been improved to generate better-optimized 4796 code. Changes include switching to LRA, more accurate cost models, 4797 and more compact code for addressing static variables. 4798 * New command-line options -mgprel-sec= and -mr0rel-sec= have been 4799 added. 4800 * The stack-smashing protection options are now enabled on Nios II. 4801 4802 PA-RISC 4803 4804 * The default call ABI on 32-bit linux has been changed from callee 4805 copies to caller copies. This affects objects larger than eight 4806 bytes passed by value. The goal is to improve compatibility with 4807 x86 and resolve issues with OpenMP. 4808 * Other PA-RISC targets are unchanged. 4809 4810 PowerPC / PowerPC64 / RS6000 4811 4812 * The PowerPC SPE support is split off to a separate powerpcspe port. 4813 The separate port is deprecated and might be removed in a future 4814 release. 4815 * The Paired Single support (as used on some PPC750 CPUs, -mpaired, 4816 powerpc*-*-linux*paired*) is deprecated and will be removed in a 4817 future release. 4818 * The Xilinx floating point support (-mxilinx-fpu, 4819 powerpc-xilinx-eabi*) is deprecated and will be removed in a future 4820 release. 4821 * Support for using big-endian AltiVec intrinsics on a little-endian 4822 target (-maltivec=be) is deprecated and will be removed in a future 4823 release. 4824 4825 Tile 4826 4827 * The TILE-Gx port is deprecated and will be removed in a future 4828 release. 4829 4830 Operating Systems 4831 4832 Windows 4833 4834 * GCC on Microsoft Windows can now be configured via 4835 --enable-mingw-wildcard or --disable-mingw-wildcard to force a 4836 specific behavior for GCC itself with regards to supporting the 4837 wildcard character. Prior versions of GCC would follow the 4838 configuration of the MinGW runtime. This behavior can still be 4839 obtained by not using the above options or by using 4840 --enable-mingw-wildcard=platform. 4841 4842 Improvements for plugin authors 4843 4844 * Plugins can now register a callback hook for when comments are 4845 encountered by the C and C++ compilers, e.g. allowing for plugins 4846 to handle documentation markup in code comments. 4847 * The gdbinit support script for debugging GCC now has a 4848 break-on-diagnostic command, providing an easy way to trigger a 4849 breakpoint whenever a diagnostic is emitted. 4850 * The API for creating fix-it hints now supports newlines, and for 4851 emitting mutually incompatible fix-it hints for one diagnostic. 4852 4853 GCC 8.1 4854 4855 This is the [30]list of problem reports (PRs) from GCC's bug tracking 4856 system that are known to be fixed in the 8.1 release. This list might 4857 not be complete (that is, it is possible that some PRs that have been 4858 fixed are not listed here). 4859 4860 GCC 8.2 4861 4862 This is the [31]list of problem reports (PRs) from GCC's bug tracking 4863 system that are known to be fixed in the 8.2 release. This list might 4864 not be complete (that is, it is possible that some PRs that have been 4865 fixed are not listed here). 4866 4867 General Improvements 4868 4869 * Fixed LTO link-time performance problems caused by an overflow in 4870 the partitioning algorithm while building large binaries. 4871 4872 Language Specific Changes 4873 4874 C++ 4875 4876 GCC 8.2 fixed a bug introduced in GCC 8.1 affecting passing or 4877 returning of classes with a deleted copy constructor and defaulted 4878 trivial move constructor (bug [32]c++/86094). GCC 8.2 introduces 4879 -fabi-version=13 and makes it the default, ABI incompatibilities 4880 between GCC 8.1 and 8.2 can be reported with -Wabi=12. See [33]C++ 4881 changes for more details. 4882 4883 Target Specific Changes 4884 4885 IA-32/x86-64 4886 4887 * -mtune=native performance regression [34]PR84413 on Intel Skylake 4888 processors has been fixed. 4889 4890 GCC 8.3 4891 4892 This is the [35]list of problem reports (PRs) from GCC's bug tracking 4893 system that are known to be fixed in the 8.3 release. This list might 4894 not be complete (that is, it is possible that some PRs that have been 4895 fixed are not listed here). 4896 4897 Windows 4898 4899 * A C++ Microsoft ABI bitfield layout bug, [36]PR87137 has been 4900 fixed. A non-field declaration could cause the current bitfield 4901 allocation unit to be completed, incorrectly placing a following 4902 bitfield into a new allocation unit. The Microsoft ABI is selected 4903 for: 4904 + Mingw targets 4905 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 4906 option is specified, or __attribute__((ms_struct)) is used 4907 + SuperH targets when the -mhitachi option is specified, or 4908 __attribute__((renesas)) is used 4909 GCC 8 introduced additional cases of this defect, but rather than 4910 resolve only those regressions, we decided to resolve all the cases 4911 of this defect in single change. 4912 4913 GCC 8.4 4914 4915 This is the [37]list of problem reports (PRs) from GCC's bug tracking 4916 system that are known to be fixed in the 8.4 release. This list might 4917 not be complete (that is, it is possible that some PRs that have been 4918 fixed are not listed here). 4919 4920 GCC 8.5 4921 4922 This is the [38]list of problem reports (PRs) from GCC's bug tracking 4923 system that are known to be fixed in the 8.5 release. This list might 4924 not be complete (that is, it is possible that some PRs that have been 4925 fixed are not listed here). 4926 4927 Target Specific Changes 4928 4929 AArch64 4930 4931 * The option -moutline-atomics has been added to aid deployment of 4932 the Large System Extensions (LSE) on GNU/Linux systems built with a 4933 baseline architecture targeting Armv8-A. When the option is 4934 specified code is emitted to detect the presence of LSE 4935 instructions at run time and use them for standard atomic 4936 operations. For more information please refer to the documentation. 4937 4938 4939 For questions related to the use of GCC, please consult these web 4940 pages and the [39]GCC manuals. If that fails, the 4941 [40]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 4942 web pages and the development of GCC are welcome on our developer 4943 list at [41]gcc (a] gcc.gnu.org. All of [42]our lists have public 4944 archives. 4945 4946 Copyright (C) [43]Free Software Foundation, Inc. Verbatim copying and 4947 distribution of this entire article is permitted in any medium, 4948 provided this notice is preserved. 4949 4950 These pages are [44]maintained by the GCC team. Last modified 4951 2023-01-11. 4952 4953 References 4954 4955 1. http://gcc.gnu.org/gcc-8/porting_to.html 4956 2. http://gcc.gnu.org/onlinedocs/index.html#current 4957 3. https://gcc.gnu.org/ml/gcc/2018-04/msg00102.html 4958 4. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmultistatement-macros 4959 5. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wstringop-truncation 4960 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944 4961 7. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wif-not-aligned 4962 8. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Common-Variable-Attributes.html#index-warn_005fif_005fnot_005faligned-variable-attribute 4963 9. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmissing-attributes 4964 10. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wpacked-not-aligned 4965 11. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Warray-bounds 4966 12. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wrestrict 4967 13. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-overflow 4968 14. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-truncation 4969 15. https://gcc.gnu.org/PR86094 4970 16. https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wclass-memaccess 4971 17. http://gcc.gnu.org/projects/cxx-status.html#cxx2a 4972 18. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_vector 4973 19. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/expressions.html#gcc_jit_context_new_rvalue_from_vector 4974 20. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_aligned 4975 21. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/function-pointers.html#gcc_jit_function_get_address 4976 22. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/contexts.html#gcc_jit_context_dump_reproducer_to_file 4977 23. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/ARM-Options.html#ARM-Options 4978 24. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Options.html 4979 25. https://sourceware.org/PR21472 4980 26. https://gcc.gnu.org/PR20296 4981 27. https://sourceware.org/binutils/docs-2.29/as/AVR-Pseudo-Instructions.html 4982 28. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Function-Attributes.html 4983 29. https://sourceware.org/PR21683 4984 30. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.0 4985 31. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.2 4986 32. https://gcc.gnu.org/PR86094 4987 33. http://gcc.gnu.org/gcc-8/changes.html#cxx 4988 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84413 4989 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.3 4990 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137 4991 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.4 4992 38. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.5 4993 39. https://gcc.gnu.org/onlinedocs/ 4994 40. mailto:gcc-help (a] gcc.gnu.org 4995 41. mailto:gcc (a] gcc.gnu.org 4996 42. https://gcc.gnu.org/lists.html 4997 43. https://www.fsf.org/ 4998 44. https://gcc.gnu.org/about.html 4999 ====================================================================== 5000 http://gcc.gnu.org/gcc-7/index.html 5001 5002 GCC 7 Release Series 5003 5004 (This release series is no longer supported.) 5005 5006 Nov 14, 2019 5007 5008 The [1]GNU project and the GCC developers are pleased to announce the 5009 release of GCC 7.5. 5010 5011 This release is a bug-fix release, containing fixes for regressions in 5012 GCC 7.4 relative to previous releases of GCC. 5013 5014 Release History 5015 5016 GCC 7.5 5017 Nov 14, 2019 ([2]changes, [3]documentation) 5018 5019 GCC 7.4 5020 Dec 6, 2018 ([4]changes, [5]documentation) 5021 5022 GCC 7.3 5023 Jan 25, 2018 ([6]changes, [7]documentation) 5024 5025 GCC 7.2 5026 Aug 14, 2017 ([8]changes, [9]documentation) 5027 5028 GCC 7.1 5029 May 2, 2017 ([10]changes, [11]documentation) 5030 5031 References and Acknowledgements 5032 5033 GCC used to stand for the GNU C Compiler, but since the compiler 5034 supports several other languages aside from C, it now stands for the 5035 GNU Compiler Collection. 5036 5037 A list of [12]successful builds is updated as new information becomes 5038 available. 5039 5040 The GCC developers would like to thank the numerous people that have 5041 contributed new features, improvements, bug fixes, and other changes as 5042 well as test results to GCC. This [13]amazing group of volunteers is 5043 what makes GCC successful. 5044 5045 For additional information about GCC please refer to the [14]GCC 5046 project web site or contact the [15]GCC development mailing list. 5047 5048 To obtain GCC please use [16]our mirror sites or [17]our version 5049 control system. 5050 5051 5052 For questions related to the use of GCC, please consult these web 5053 pages and the [18]GCC manuals. If that fails, the 5054 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 5055 web pages and the development of GCC are welcome on our developer 5056 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 5057 archives. 5058 5059 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 5060 distribution of this entire article is permitted in any medium, 5061 provided this notice is preserved. 5062 5063 These pages are [23]maintained by the GCC team. Last modified 5064 2022-10-26. 5065 5066 References 5067 5068 1. http://www.gnu.org/ 5069 2. http://gcc.gnu.org/gcc-7/changes.html 5070 3. http://gcc.gnu.org/onlinedocs/7.5.0/ 5071 4. http://gcc.gnu.org/gcc-7/changes.html 5072 5. http://gcc.gnu.org/onlinedocs/7.4.0/ 5073 6. http://gcc.gnu.org/gcc-7/changes.html 5074 7. http://gcc.gnu.org/onlinedocs/7.3.0/ 5075 8. http://gcc.gnu.org/gcc-7/changes.html 5076 9. http://gcc.gnu.org/onlinedocs/7.2.0/ 5077 10. http://gcc.gnu.org/gcc-7/changes.html 5078 11. http://gcc.gnu.org/onlinedocs/7.1.0/ 5079 12. http://gcc.gnu.org/gcc-7/buildstat.html 5080 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 5081 14. http://gcc.gnu.org/index.html 5082 15. mailto:gcc (a] gcc.gnu.org 5083 16. http://gcc.gnu.org/mirrors.html 5084 17. http://gcc.gnu.org/git.html 5085 18. https://gcc.gnu.org/onlinedocs/ 5086 19. mailto:gcc-help (a] gcc.gnu.org 5087 20. mailto:gcc (a] gcc.gnu.org 5088 21. https://gcc.gnu.org/lists.html 5089 22. https://www.fsf.org/ 5090 23. https://gcc.gnu.org/about.html 5091 ====================================================================== 5092 http://gcc.gnu.org/gcc-7/changes.html 5093 5094 GCC 7 Release Series 5095 Changes, New Features, and Fixes 5096 5097 This page is a brief summary of some of the huge number of improvements 5098 in GCC 7. For more information, see the [1]Porting to GCC 7 page and 5099 the [2]full GCC documentation. 5100 5101 Caveats 5102 5103 * GCC now uses [3]LRA (a new local register allocator) by default for 5104 new targets. 5105 * The non-standard C++0x type traits has_trivial_default_constructor, 5106 has_trivial_copy_constructor and has_trivial_copy_assign have been 5107 removed. 5108 * The libstdc++ [4]Profile Mode has been deprecated and will be 5109 removed in a future version. 5110 * The Cilk+ extensions to the C and C++ languages have been 5111 deprecated. 5112 * On ARM targets (arm*-*-*), [5]a bug introduced in GCC 5 that 5113 affects conformance to the procedure call standard (AAPCS) has been 5114 fixed. The bug affects some C++ code where class objects are passed 5115 by value to functions and could result in incorrect or inconsistent 5116 code being generated. This is an ABI change. If the option -Wpsabi 5117 is enabled (on by default) the compiler will emit a diagnostic note 5118 for code that might be affected. 5119 5120 General Optimizer Improvements 5121 5122 * GCC 7 can determine the return value or range of return values of 5123 some calls to the sprintf family of functions and make it available 5124 to other optimization passes. Some calls to the snprintf function 5125 with a zero size argument can be folded into constants. This 5126 optimization is included in -O1 and can be selectively controlled 5127 by the -fprintf-return-value option. 5128 * A new store merging pass has been added. It merges constant stores 5129 to adjacent memory locations into fewer, wider, stores. It is 5130 enabled by the -fstore-merging option and at the -O2 optimization 5131 level or higher (and -Os). 5132 * A new code hoisting optimization has been added to the partial 5133 redundancy elimination pass. It attempts to move evaluation of 5134 expressions executed on all paths to the function exit as early as 5135 possible. This primarily helps improve code size, but can improve 5136 the speed of the generated code as well. It is enabled by the 5137 -fcode-hoisting option and at the -O2 optimization level or higher 5138 (and -Os). 5139 * A new interprocedural bitwise constant propagation optimization has 5140 been added, which propagates knowledge about which bits of 5141 variables are known to be zero (including pointer alignment 5142 information) across the call graph. It is enabled by the 5143 -fipa-bit-cp option if -fipa-cp is enabled as well, and is enabled 5144 at the -O2 optimization level and higher (and -Os). This 5145 optimization supersedes interprocedural alignment propagation of 5146 GCC 6, and therefore the option -fipa-cp-alignment is now 5147 deprecated and ignored. 5148 * A new interprocedural value range propagation optimization has been 5149 added, which propagates integral range information across the call 5150 graph when variable values can be proven to be within those ranges. 5151 It is enabled by the -fipa-vrp option and at the -O2 optimization 5152 level and higher (and -Os). 5153 * A new loop splitting optimization pass has been added. Certain 5154 loops which contain a condition that is always true on one side of 5155 the iteration space and always false on the other are split into 5156 two loops, such that each of the two new loops iterates on just one 5157 side of the iteration space and the condition does not need to be 5158 checked inside of the loop. It is enabled by the -fsplit-loops 5159 option and at the -O3 optimization level or higher. 5160 * The shrink-wrapping optimization can now separate portions of 5161 prologues and epilogues to improve performance if some of the work 5162 done traditionally by prologues and epilogues is not needed on 5163 certain paths. This is controlled by the -fshrink-wrap-separate 5164 option, enabled by default. It requires target support, which is 5165 currently only implemented in the PowerPC and AArch64 ports. 5166 * AddressSanitizer gained a new sanitization option, 5167 -fsanitize-address-use-after-scope, which enables sanitization of 5168 variables whose address is taken and used after a scope where the 5169 variable is defined: 5170 5171 int 5172 main (int argc, char **argv) 5173 { 5174 char *ptr; 5175 { 5176 char my_char; 5177 ptr = &my_char; 5178 } 5179 5180 *ptr = 123; 5181 return *ptr; 5182 } 5183 5184 ==28882==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffb8dba99 5185 0 at pc 0x0000004006d5 bp 0x7fffb8dba960 sp 0x7fffb8dba958 5186 WRITE of size 1 at 0x7fffb8dba990 thread T0 5187 #0 0x4006d4 in main /tmp/use-after-scope-1.c:10 5188 #1 0x7f9c71943290 in __libc_start_main (/lib64/libc.so.6+0x20290) 5189 #2 0x400739 in _start (/tmp/a.out+0x400739) 5190 5191 Address 0x7fffb8dba990 is located in stack of thread T0 at offset 32 in frame 5192 #0 0x40067f in main /tmp/use-after-scope-1.c:3 5193 5194 This frame has 1 object(s): 5195 [32, 33) 'my_char' <== Memory access at offset 32 is inside this variable 5196 5197 The option is enabled by default with -fsanitize=address and 5198 disabled by default with -fsanitize=kernel-address. Compared to the 5199 LLVM compiler, where the option already exists, the implementation 5200 in the GCC compiler has some improvements and advantages: 5201 + Complex uses of gotos and case labels are properly handled and 5202 should not report any false positive or false negatives. 5203 + C++ temporaries are sanitized. 5204 + Sanitization can handle invalid memory stores that are 5205 optimized out by the LLVM compiler when optimization is 5206 enabled. 5207 * The -fsanitize=signed-integer-overflow suboption of the 5208 UndefinedBehavior Sanitizer now diagnoses arithmetic overflows even 5209 on arithmetic operations with generic vectors. 5210 * Version 5 of the DWARF debugging information standard is supported 5211 through the -gdwarf-5 option. The DWARF version 4 debugging 5212 information remains the default until consumers of debugging 5213 information are adjusted. 5214 5215 New Languages and Language specific improvements 5216 5217 OpenACC support in C, C++, and Fortran continues to be maintained and 5218 improved. See the [6]OpenACC and [7]Offloading wiki pages for further 5219 information. 5220 5221 Ada 5222 5223 * On mainstream native platforms, Ada programs no longer require the 5224 stack to be made executable in order to run properly. 5225 5226 BRIG (HSAIL) 5227 5228 Support for processing BRIG 1.0 files was added in this release. BRIG 5229 is a binary format for HSAIL (Heterogeneous System Architecture 5230 Intermediate Language). The BRIG front end can be used for implementing 5231 HSAIL "finalizers" (compilation of HSAIL to a native ISA) for 5232 GCC-supported targets. An implementation of an HSAIL runtime library, 5233 libhsail-rt is also included. 5234 5235 C family 5236 5237 * New command-line options have been added for the C and C++ 5238 compilers: 5239 + -Wimplicit-fallthrough warns when a switch case falls through. 5240 This warning has five different levels. The compiler is able 5241 to parse a wide range of fallthrough comments, depending on 5242 the level. It also handles control-flow statements, such as 5243 ifs. It's possible to suppress the warning by either adding a 5244 fallthrough comment, or by using a null statement: 5245 __attribute__ ((fallthrough)); (C, C++), or [[fallthrough]]; 5246 (C++17), or [[gnu::fallthrough]]; (C++11/C++14). This warning 5247 is enabled by -Wextra. 5248 + -Wpointer-compare warns when a pointer is compared with a zero 5249 character constant. Such code is now invalid in C++11 and GCC 5250 rejects it. This warning is enabled by default. 5251 + -Wduplicated-branches warns when an if-else has identical 5252 branches. 5253 + -Wrestrict warns when an argument passed to a 5254 restrict-qualified parameter aliases with another argument. 5255 + -Wmemset-elt-size warns for memset calls, when the first 5256 argument references an array, and the third argument is a 5257 number equal to the number of elements of the array, but not 5258 the size of the array. This warning is enabled by -Wall. 5259 + -Wint-in-bool-context warns about suspicious uses of integer 5260 values where boolean values are expected. This warning is 5261 enabled by -Wall. 5262 + -Wswitch-unreachable warns when a switch statement has 5263 statements between the controlling expression and the first 5264 case label which will never be executed. This warning is 5265 enabled by default. 5266 + -Wexpansion-to-defined warns when defined is used outside #if. 5267 This warning is enabled by -Wextra or -Wpedantic. 5268 + -Wregister warns about uses of the register storage specifier. 5269 In C++17 this keyword has been removed and for C++17 this is a 5270 pedantic warning enabled by default. The warning is not 5271 emitted for the GNU Explicit Register Variables extension. 5272 + -Wvla-larger-than=N warns about unbounded uses of 5273 variable-length arrays, and about bounded uses of 5274 variable-length arrays whose bound can be larger than N bytes. 5275 + -Wduplicate-decl-specifier warns when a declaration has 5276 duplicate const, volatile, restrict or _Atomic specifier. This 5277 warning is enabled by -Wall. 5278 * GCC 6's C and C++ front ends were able to offer suggestions for 5279 misspelled field names: 5280 5281 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 5282 you mean 'color'? 5283 return ptr->colour; 5284 ^~~~~~ 5285 5286 GCC 7 greatly expands the scope of these suggestions. Firstly, it 5287 adds fix-it hints to such suggestions: 5288 5289 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 5290 you mean 'color'? 5291 return ptr->colour; 5292 ^~~~~~ 5293 color 5294 5295 The suggestions now cover many other things, such as misspelled 5296 function names: 5297 5298 spellcheck-identifiers.c:11:3: warning: implicit declaration of function 'gtk_wi 5299 dget_showall'; did you mean 'gtk_widget_show_all'? [-Wimplicit-function-declarat 5300 ion] 5301 gtk_widget_showall (w); 5302 ^~~~~~~~~~~~~~~~~~ 5303 gtk_widget_show_all 5304 5305 misspelled macro names and enum values: 5306 5307 spellcheck-identifiers.cc:85:11: error: 'MAX_ITEM' undeclared here (not in a fun 5308 ction); did you mean 'MAX_ITEMS'? 5309 int array[MAX_ITEM]; 5310 ^~~~~~~~ 5311 MAX_ITEMS 5312 5313 misspelled type names: 5314 5315 spellcheck-typenames.c:7:14: error: unknown type name 'singed'; did you mean 'si 5316 gned'? 5317 void test (singed char e); 5318 ^~~~~~ 5319 signed 5320 5321 and, in the C front end, named initializers: 5322 5323 test.c:7:20: error: 'struct s' has no member named 'colour'; did you mean 'color 5324 '? 5325 struct s test = { .colour = 3 }; 5326 ^~~~~~ 5327 color 5328 5329 * The preprocessor can now offer suggestions for misspelled 5330 directives, e.g.: 5331 5332 test.c:5:2: error:invalid preprocessing directive #endfi; did you mean #endif? 5333 #endfi 5334 ^~~~~ 5335 endif 5336 5337 * Warnings about format strings now underline the pertinent part of 5338 the string, and can offer suggested fixes. In some cases, the 5339 pertinent argument is underlined. 5340 5341 test.c:51:29: warning: format '%s' expects argument of type 'char *', but argume 5342 nt 3 has type 'int' [-Wformat=] 5343 printf ("foo: %d bar: %s baz: %d", 100, i + j, 102); 5344 ~^ ~~~~~ 5345 %d 5346 5347 * The new -Wdangling-else command-line option has been split out of 5348 -Wparentheses and warns about dangling else. 5349 * The -Wshadow warning has been split into three variants. 5350 -Wshadow=global warns for any shadowing. This is the default when 5351 using -Wshadow without any argument. -Wshadow=local only warns for 5352 a local variable shadowing another local variable or parameter. 5353 -Wshadow=compatible-local only warns for a local variable shadowing 5354 another local variable or parameter whose type is compatible (in 5355 C++ compatible means that the type of the shadowing variable can be 5356 converted to that of the shadowed variable). 5357 The following example shows the different kinds of shadow warnings: 5358 5359 enum operation { add, count }; 5360 struct container { int nr; }; 5361 5362 int 5363 container_count (struct container c, int count) 5364 { 5365 int r = 0; 5366 for (int count = 0; count > 0; count--) 5367 { 5368 struct container count = c; 5369 r += count.nr; 5370 } 5371 return r; 5372 } 5373 5374 -Wshadow=compatible-local will warn for the parameter being 5375 shadowed with the same type: 5376 5377 warn-test.c:8:12: warning: declaration of 'count' shadows a parameter [-Wshadow= 5378 compatible-local] 5379 for (int count = 0; count > 0; count--) 5380 ^~~~~ 5381 warn-test.c:5:42: note: shadowed declaration is here 5382 container_count (struct container c, int count) 5383 ^~~~~ 5384 5385 -Wshadow=local will warn for the above and for the shadowed 5386 declaration with incompatible type: 5387 5388 warn-test.c:10:24: warning: declaration of 'count' shadows a previous local [-Ws 5389 hadow=local] 5390 struct container count = c; 5391 ^~~~~ 5392 warn-test.c:8:12: note: shadowed declaration is here 5393 for (int count = 0; count > 0; count--) 5394 ^~~~~ 5395 5396 -Wshadow=global will warn for all of the above and the shadowing of 5397 the global declaration: 5398 5399 warn-test.c:5:42: warning: declaration of 'count' shadows a global declaration [ 5400 -Wshadow] 5401 container_count (struct container c, int count) 5402 ^~~~~ 5403 warn-test.c:1:23: note: shadowed declaration is here 5404 enum operation { add, count }; 5405 ^~~~~ 5406 5407 * GCC 7 contains a number of enhancements that help detect buffer 5408 overflow and other forms of invalid memory accesses. 5409 + The -Walloc-size-larger-than=size option detects calls to 5410 standard and user-defined memory allocation functions 5411 decorated with attribute alloc_size whose argument exceeds the 5412 specified size (PTRDIFF_MAX by default). The option also 5413 detects arithmetic overflow in the computation of the size in 5414 two-argument allocation functions like calloc where the total 5415 size is the product of the two arguments. Since calls with an 5416 excessive size cannot succeed they are typically the result of 5417 programming errors. Such bugs have been known to be the source 5418 of security vulnerabilities and a target of exploits. 5419 -Walloc-size-larger-than=PTRDIFF_MAX is included in -Wall. 5420 For example, the following call to malloc incorrectly tries to 5421 avoid passing a negative argument to the function and instead 5422 ends up unconditionally invoking it with an argument less than 5423 or equal to zero. Since after conversion to the type of the 5424 argument of the function (size_t) a negative argument results 5425 in a value in excess of the maximum PTRDIFF_MAX the call is 5426 diagnosed. 5427 5428 void* f (int n) 5429 { 5430 return malloc (n > 0 ? 0 : n); 5431 } 5432 5433 warning: argument 1 range [2147483648, 4294967295] exceeds maximum object size 2 5434 147483647 [-Walloc-size-larger-than=] 5435 5436 + The -Walloc-zero option detects calls to standard and 5437 user-defined memory allocation functions decorated with 5438 attribute alloc_size with a zero argument. -Walloc-zero is not 5439 included in either -Wall or -Wextra and must be explicitly 5440 enabled. 5441 + The -Walloca option detects all calls to the alloca function 5442 in the program. -Walloca is not included in either -Wall or 5443 -Wextra and must be explicitly enabled. 5444 + The -Walloca-larger-than=size option detects calls to the 5445 alloca function whose argument either may exceed the specified 5446 size, or that is not known to be sufficiently constrained to 5447 avoid exceeding it. -Walloca-larger-than is not included in 5448 either -Wall or -Wextra and must be explicitly enabled. 5449 For example, compiling the following snippet with 5450 -Walloca-larger-than=1024 results in a warning because even 5451 though the code appears to call alloca only with sizes of 1kb 5452 and less, since n is signed, a negative value would result in 5453 a call to the function well in excess of the limit. 5454 5455 void f (int n) 5456 { 5457 char *d; 5458 if (n < 1025) 5459 d = alloca (n); 5460 else 5461 d = malloc (n); 5462 ... 5463 } 5464 5465 warning: argument to 'alloca may be too large due to conversion from 'int' to 'l 5466 ong unsigned int' [-Walloca-larger-than=] 5467 5468 In contrast, a call to alloca that isn't bounded at all such 5469 as in the following function will elicit the warning below 5470 regardless of the size argument to the option. 5471 5472 void f (size_t n) 5473 { 5474 char *d = alloca (n); 5475 ... 5476 } 5477 5478 warning: unbounded use of 'alloca' [-Walloca-larger-than=] 5479 5480 + The -Wformat-overflow=level option detects certain and likely 5481 buffer overflow in calls to the sprintf family of formatted 5482 output functions. Although the option is enabled even without 5483 optimization it works best with -O2 and higher. 5484 For example, in the following snippet the call to sprintf is 5485 diagnosed because even though its output has been constrained 5486 using the modulo operation it could result in as many as three 5487 bytes if mday were negative. The solution is to either 5488 allocate a larger buffer or make sure the argument is not 5489 negative, for example by changing mday's type to unsigned or 5490 by making the type of the second operand of the modulo 5491 expression unsigned: 100U. 5492 5493 void* f (int mday) 5494 { 5495 char *buf = malloc (3); 5496 sprintf (buf, "%02i", mday % 100); 5497 return buf; 5498 } 5499 5500 warning: 'sprintf may write a terminating nul past the end of the destination [- 5501 Wformat-overflow=] 5502 note: 'sprintf' output between 3 and 4 bytes into a destination of size 3 5503 5504 + The -Wformat-truncation=level option detects certain and 5505 likely output truncation in calls to the snprintf family of 5506 formatted output functions. -Wformat-truncation=1 is included 5507 in -Wall and enabled without optimization but works best with 5508 -O2 and higher. 5509 For example, the following function attempts to format an 5510 integer between 0 and 255 in hexadecimal, including the 0x 5511 prefix, into a buffer of four characters. But since the 5512 function must always terminate output by the null character 5513 ('\0') such a buffer is only big enough to fit just one digit 5514 plus the prefix. Therefore the snprintf call is diagnosed. To 5515 avoid the warning either use a bigger buffer or handle the 5516 function's return value which indicates whether or not its 5517 output has been truncated. 5518 5519 void f (unsigned x) 5520 { 5521 char d[4]; 5522 snprintf (d, sizeof d, "%#02x", x & 0xff); 5523 ... 5524 } 5525 5526 warning: 'snprintf' output may be truncated before the last format character [-W 5527 format-truncation=] 5528 note: 'snprintf' output between 3 and 5 bytes into a destination of size 4 5529 5530 + The -Wnonnull option has been enhanced to detect a broader set 5531 of cases of passing null pointers to functions that expect a 5532 non-null argument (those decorated with attribute nonnull). By 5533 taking advantage of optimizations the option can detect many 5534 more cases of the problem than in prior GCC versions. 5535 + The -Wstringop-overflow=type option detects buffer overflow in 5536 calls to string handling functions like memcpy and strcpy. The 5537 option relies on [8]Object Size Checking and has an effect 5538 similar to defining the _FORTIFY_SOURCE macro. 5539 -Wstringop-overflow=2 is enabled by default. 5540 For example, in the following snippet, because the call to 5541 strncat specifies a maximum that allows the function to write 5542 past the end of the destination, it is diagnosed. To correct 5543 the problem and avoid the overflow the function should be 5544 called with a size of at most sizeof d - strlen(d) - 1. 5545 5546 void f (const char *fname) 5547 { 5548 char d[8]; 5549 strncpy (d, "/tmp/", sizeof d); 5550 strncat (d, fname, sizeof d); 5551 ... 5552 } 5553 5554 warning: specified bound 8 equals the size of the destination [-Wstringop-overfl 5555 ow=] 5556 5557 * The <limits.h> header provided by GCC defines macros such as 5558 INT_WIDTH for the width in bits of integer types, if 5559 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 5560 included. The <stdint.h> header defines such macros as SIZE_WIDTH 5561 and INTMAX_WIDTH for the width of some standard typedef names for 5562 integer types, again if __STDC_WANT_IEC_60559_BFP_EXT__ is defined 5563 before the header is included; note that GCC's implementation of 5564 this header is only used for freestanding compilations, not hosted 5565 compilations, on most systems. These macros come from ISO/IEC TS 5566 18661-1:2014. 5567 * The <float.h> header provided by GCC defines the macro 5568 CR_DECIMAL_DIG, from ISO/IEC TS 18661-1:2014, if 5569 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 5570 included. This represents the number of decimal digits for which 5571 conversions between decimal character strings and binary formats, 5572 in both directions, are correctly rounded, and currently has the 5573 value of UINTMAX_MAX on all systems, reflecting that GCC's 5574 compile-time conversions are correctly rounded for any number of 5575 digits. 5576 * New __builtin_add_overflow_p, __builtin_sub_overflow_p, 5577 __builtin_mul_overflow_p built-in functions have been added. These 5578 work similarly to their siblings without the _p suffix, but do not 5579 actually store the result of the arithmetics anywhere, just return 5580 whether the operation would overflow. Calls to these built-ins with 5581 integer constant arguments evaluate to integer constants 5582 expressions. 5583 For example, in the following, c is assigned the result of a * b 5584 only if the multiplication does not overflow, otherwise it is 5585 assigned the value zero. The multiplication is performed at 5586 compile-time and without triggering a -Woverflow warning. 5587 5588 enum { 5589 a = 12345678, 5590 b = 87654321, 5591 c = __builtin_mul_overflow_p (a, b, a) ? 0 : a * b 5592 }; 5593 5594 C 5595 5596 * The C front end now supports type names _FloatN for floating-point 5597 types with IEEE interchange formats and _FloatNx for floating-point 5598 types with IEEE extended formats. These type names come from 5599 ISO/IEC TS 18661-3:2015. 5600 The set of types supported depends on the target for which GCC is 5601 configured. Most targets support _Float32, _Float32x and _Float64. 5602 _Float128 is supported on targets where IEEE binary128 encoding was 5603 already supported as long double or __float128. _Float64x is 5604 supported on targets where a type with either binary128 or Intel 5605 extended precision format is available. 5606 Constants with these types are supported using suffixes fN, FN, fNx 5607 and FNx (e.g., 1.2f128 or 2.3F64x). Macros such as FLT128_MAX are 5608 defined in <float.h> if __STDC_WANT_IEC_60559_TYPES_EXT__ is 5609 defined before it is included. 5610 These new types are always distinct from each other and from float, 5611 double and long double, even if they have the same encoding. 5612 Complex types such as _Complex _Float128 are also supported. 5613 Type-generic built-in functions such as __builtin_isinf support the 5614 new types, and the following type-specific built-in functions have 5615 versions (suffixed fN or fNx) for the new types: 5616 __builtin_copysign, __builtin_fabs, __builtin_huge_val, 5617 __builtin_inf, __builtin_nan, __builtin_nans. 5618 * Compilation with -fopenmp is now compatible with the C11 _Atomic 5619 keyword. 5620 5621 C++ 5622 5623 * The C++ front end has experimental support for all of the current 5624 C++17 draft with the -std=c++1z or -std=gnu++1z flags, including if 5625 constexpr, class template argument deduction, auto template 5626 parameters, and structured bindings. For a full list of new 5627 features, see [9]the C++ status page. 5628 * C++17 support for new of over-aligned types can be enabled in other 5629 modes with the -faligned-new flag. 5630 * The C++17 evaluation order requirements can be selected in other 5631 modes with the -fstrong-eval-order flag, or disabled in C++17 mode 5632 with -fno-strong-eval-order. 5633 * The default semantics of inherited constructors has changed in all 5634 modes, following [10]P0136. Essentially, overload resolution 5635 happens as if calling the inherited constructor directly, and the 5636 compiler fills in construction of the other bases and members as 5637 needed. Most uses should not need any changes. The old behavior can 5638 be restored with -fno-new-inheriting-ctors, or -fabi-version less 5639 than 11. 5640 * The resolution of DR 150 on matching of template template 5641 parameters, allowing default template arguments to make a template 5642 match a parameter, is currently enabled by default in C++17 mode 5643 only. The default can be overridden with -f{no-,}new-ttp-matching. 5644 * The C++ front end will now provide fix-it hints for some missing 5645 semicolons, allowing for automatic fixes by IDEs: 5646 5647 test.cc:4:11: error: expected ';' after class definition 5648 class a {} 5649 ^ 5650 ; 5651 5652 * -Waligned-new has been added to the C++ front end. It warns about 5653 new of type with extended alignment without -faligned-new. 5654 5655 Runtime Library (libstdc++) 5656 5657 * The type of exception thrown by iostreams, std::ios_base::failure, 5658 now uses the [11]cxx11 ABI. 5659 * Experimental support for C++17, including the following new 5660 features: 5661 + std::string_view; 5662 + std::any, std::optional, and std::variant; 5663 + std::invoke, std::is_invocable, std::is_nothrow_invocable, and 5664 invoke_result; 5665 + std::is_swappable, and std::is_nothrow_swappable; 5666 + std::apply, and std::make_from_tuple; 5667 + std::void_t, std::bool_constant, std::conjunction, 5668 std::disjunction, and std::negation; 5669 + Variable templates for type traits; 5670 + Mathematical Special Functions; 5671 + std::chrono::floor, std::chrono::ceil, std::chrono::round, and 5672 std::chrono::abs; 5673 + std::clamp, std::gcd, std::lcm, 3-dimensional std::hypot; 5674 + std::scoped_lock, std::shared_mutex, 5675 std::atomic<T>::is_always_lock_free; 5676 + std::sample, std::default_searcher, std::boyer_moore_searcher 5677 and std::boyer_moore_horspool_searcher; 5678 + Extraction and re-insertion of map and set nodes, try_emplace 5679 members for maps, and functions for accessing containers 5680 std::size, std::empty, and std::data; 5681 + std::shared_ptr support for arrays, 5682 std::shared_ptr<T>::weak_type, 5683 std::enable_shared_from_this<T>::weak_from_this(), and 5684 std::owner_less<void>; 5685 + std::byte; 5686 + std::as_const, std::not_fn, 5687 std::has_unique_object_representations, constexpr 5688 std::addressof. 5689 Thanks to Daniel Krgler, Tim Shen, Edward Smith-Rowland, and Ville 5690 Voutilainen for work on the C++17 support. 5691 * A new power-of-two rehashing policy for use with the _Hashtable 5692 internals, thanks to Franois Dumont. 5693 5694 Fortran 5695 5696 * Support for a number of extensions for compatibility with legacy 5697 code with new flags: 5698 + -fdec-structure Support for DEC STRUCTURE and UNION 5699 + -fdec-intrinsic-ints Support for new integer intrinsics with 5700 B/I/J/K prefixes such as BABS, JIAND... 5701 + -fdec-math Support for additional math intrinsics, including 5702 COTAN and degree-valued trigonometric functions such as TAND, 5703 ASIND... 5704 + -fdec Enable the -fdec-* family of extensions. 5705 * New flag -finit-derived to allow default initialization of 5706 derived-type variables. 5707 * Improved DO loops with step equal to 1 or -1, generates faster code 5708 without a loop preheader. A new warning, -Wundefined-do-loop, warns 5709 when a loop iterates either to HUGE(i) (with step equal to 1), or 5710 to -HUGE(i) (with step equal to -1). Invalid behavior can be caught 5711 at run time with -fcheck=do enabled: 5712 5713 program test 5714 implicit none 5715 integer(1) :: i 5716 do i = -HUGE(i)+10, -HUGE(i)-1, -1 5717 print *, i 5718 end do 5719 end program test 5720 5721 At line 8 of file do_check_12.f90 5722 Fortran runtime error: Loop iterates infinitely 5723 5724 * Version 4.5 of the [12]OpenMP specification is now partially 5725 supported in the Fortran compiler; the largest missing item is 5726 structure element mapping. 5727 * User-defined derived-type input/output (UDTIO) is added. 5728 * Derived type coarrays with allocatable and pointer components are 5729 partially supported. 5730 * Non-constant stop codes and error stop codes (Fortran 2015 5731 feature). 5732 * Derived types with allocatable components of recursive type. 5733 * Intrinsic assignment to polymorphic variables. 5734 * Improved submodule support. 5735 * Improved diagnostics (polymorphic results in pure functions). 5736 * Coarray: Support for failed images (Fortan 2015 feature). 5737 5738 Go 5739 5740 * GCC 7 provides a complete implementation of the Go 1.8.1 user 5741 packages. 5742 * Compared to the Go 1.8.1 toolchain, the garbage collector is more 5743 conservative and less concurrent. 5744 * Escape analysis is available for experimental use via the 5745 -fgo-optimize-allocs option. The -fgo-debug-escape prints 5746 information useful for debugging escape analysis choices. 5747 5748 Java (GCJ) 5749 5750 The GCC Java front end and associated libjava runtime library have been 5751 removed from GCC. 5752 5753 libgccjit 5754 5755 The libgccjit API gained support for marking calls as requiring 5756 tail-call optimization via a new entry point: 5757 [13]gcc_jit_rvalue_set_bool_require_tail_call. 5758 5759 libgccjit performs numerous checks at the API boundary, but if these 5760 succeed, it previously ignored errors and other diagnostics emitted 5761 within the core of GCC, and treated the compile of a gcc_jit_context as 5762 having succeeded. As of GCC 7 it now ensures that if any diagnostics 5763 are emitted, they are visible from the libgccjit API, and that the the 5764 context is flagged as having failed. 5765 5766 New Targets and Target Specific Improvements 5767 5768 AArch64 5769 5770 * GCC has been updated to the latest revision of the procedure call 5771 standard (AAPCS64) to provide support for parameter passing when 5772 data types have been over-aligned. 5773 * The ARMv8.3-A architecture is now supported. It can be used by 5774 specifying the -march=armv8.3-a option. 5775 * The option -msign-return-address= is supported to enable return 5776 address protection using ARMv8.3-A Pointer Authentication 5777 Extensions. For more information on the arguments accepted by this 5778 option, please refer to [14]AArch64-Options. 5779 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 5780 Extensions are now supported. They can be used by specifying the 5781 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 5782 Floating-Point Extensions introduce new half-precision data 5783 processing floating-point instructions. 5784 * Support has been added for the following processors (GCC 5785 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), Broadcom 5786 Vulcan (vulcan), Cavium ThunderX CN81xx (thunderxt81), Cavium 5787 ThunderX CN83xx (thunderxt83), Cavium ThunderX CN88xx 5788 (thunderxt88), Cavium ThunderX CN88xx pass 1.x (thunderxt88p1), 5789 Cavium ThunderX 2 CN99xx (thunderx2t99), Qualcomm Falkor (falkor). 5790 The GCC identifiers can be used as arguments to the -mcpu or -mtune 5791 options, for example: -mcpu=cortex-a73 or -mtune=vulcan or as 5792 arguments to the equivalent target attributes and pragmas. 5793 5794 ARC 5795 5796 * Added support for ARC HS and ARC EM processors. 5797 * Added support for ARC EM variation found in Intel QuarkSE SoCs. 5798 * Added support for NPS400 ARC700 based CPUs. 5799 * Thread Local Storage is now supported by ARC CPUs. 5800 * Fixed errors for ARC600 when using 32x16 multiplier option. 5801 * Fixed PIE for ARC CPUs. 5802 * New CPU templates are supported via multilib. 5803 5804 ARM 5805 5806 * Support for the ARMv5 and ARMv5E architectures has been deprecated 5807 (which have no known implementations) and will be removed in a 5808 future GCC release. Note that ARMv5T, ARMv5TE and ARMv5TEJ 5809 architectures remain supported. The values armv5 and armv5e of 5810 -march are thus deprecated. 5811 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 5812 Extensions are now supported. They can be used by specifying the 5813 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 5814 Floating-Point Extensions introduce new half-precision data 5815 processing floating-point instructions. 5816 * The ARMv8-M architecture is now supported in its two architecture 5817 profiles: ARMv8-M Baseline and ARMv8-M Mainline with its DSP and 5818 Floating-Point Extensions. They can be used by specifying the 5819 -march=armv8-m.base, armv8-m.main or armv8-m.main+dsp options. 5820 * Support has been added for the following processors (GCC 5821 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), ARM 5822 Cortex-M23 (cortex-m23) and ARM Cortex-M33 (cortex-m33). The GCC 5823 identifiers can be used as arguments to the -mcpu or -mtune 5824 options, for example: -mcpu=cortex-a73 or -mtune=cortex-m33. 5825 * A new command-line option -mpure-code has been added. It does not 5826 allow constant data to be placed in code sections. This option is 5827 only available when generating non-PIC code for ARMv7-M targets. 5828 * Support for the ACLE Coprocessor Intrinsics has been added. This 5829 enables the generation of coprocessor instructions through the use 5830 of intrinsics such as cdp, ldc, and others. 5831 * The configure option --with-multilib-list now accepts the value 5832 rmprofile to build multilib libraries for a range of embedded 5833 targets. See our [15]installation instructions for details. 5834 5835 AVR 5836 5837 * On the reduced Tiny cores, the progmem [16]variable attribute is 5838 now properly supported. Respective read-only variables are located 5839 in flash memory in section .progmem.data. No special code is needed 5840 to access such variables; the compiler automatically adds an offset 5841 of 0x4000 to all addresses, which is needed to access variables in 5842 flash memory. As opposed to ordinary cores where it is sufficient 5843 to specify the progmem attribute with definitions, on the reduced 5844 Tiny cores the attribute also has to be specified with (external) 5845 declarations: 5846 5847 extern const int array[] __attribute__((__progmem__)); 5848 5849 int get_value2 (void) 5850 { 5851 /* Access via addresses array + 0x4004 and array + 0x4005. */ 5852 return array[2]; 5853 } 5854 5855 const int* get_address (unsigned idx) 5856 { 5857 /* Returns array + 0x4000 + 2 * idx. */ 5858 return &array[idx]; 5859 } 5860 5861 * A new command-line option -Wmisspelled-isr has been added. It turns 5862 off -- or turns into errors -- warnings that are reported for 5863 interrupt service routines (ISRs) which don't follow AVR-LibC's 5864 naming convention of prefixing ISR names with __vector. 5865 * __builtin_avr_nops(n) is a new [17]built-in function that inserts n 5866 NOP instructions into the instruction stream. n must be a value 5867 known at compile time. 5868 5869 IA-32/x86-64 5870 5871 * Support for the AVX-512 Fused Multiply Accumulation Packed Single 5872 precision (4FMAPS), AVX-512 Vector Neural Network Instructions Word 5873 variable precision (4VNNIW), AVX-512 Vector Population Count 5874 (VPOPCNTDQ) and Software Guard Extensions (SGX) ISA extensions has 5875 been added. 5876 5877 NVPTX 5878 5879 * OpenMP target regions can now be offloaded to NVidia PTX GPGPUs. 5880 See the [18]Offloading Wiki on how to configure it. 5881 5882 PowerPC / PowerPC64 / RS6000 5883 5884 * The PowerPC port now uses LRA by default. 5885 * GCC now diagnoses inline assembly that clobbers register r2. This 5886 has always been invalid code, and is no longer quietly tolerated. 5887 * The PowerPC port's support for ISA 3.0 (-mcpu=power9) has been 5888 enhanced to generate more of the new instructions by default, and 5889 to provide more built-in functions to generate code for other new 5890 instructions. 5891 * The configuration option --enable-gnu-indirect-function is now 5892 enabled by default on PowerPC GNU/Linux builds. 5893 * The PowerPC port will now allow 64-bit and 32-bit integer types to 5894 be allocated to the VSX vector registers (ISA 2.06 and above). In 5895 addition, on ISA 3.0, 16-bit and 8-bit integer types can be 5896 allocated in the vector registers. Previously, only 64-bit integer 5897 types were allowed in the traditional floating point registers. 5898 * New options -mstack-protector-guard=global, 5899 -mstack-protector-guard=tls, -mstack-protector-guard-reg=, and 5900 -mstack-protector-guard-offset= change how the stack protector gets 5901 the value to use as canary. 5902 5903 S/390, System z, IBM z Systems, IBM Z 5904 5905 * Support for the IBM z14 processor has been added. When using the 5906 -march=z14 option, the compiler will generate code making use of 5907 the new instructions introduced with the vector enhancement 5908 facility and the miscellaneous instruction extension facility 2. 5909 The -mtune=z14 option enables z14 specific instruction scheduling 5910 without making use of new instructions. 5911 * Builtins for the new vector instructions have been added and can be 5912 enabled using the -mzvector option. 5913 5914 RISC-V 5915 5916 * Support for the RISC-V instruction set has been added. 5917 5918 RX 5919 5920 Basic support for atomic built-in function has been added. It is 5921 currently implemented by flipping interrupts off and on as needed. 5922 5923 SH 5924 5925 * Support for SH5/SH64 has been removed. 5926 * Improved utilization of delay slots on SH2A. 5927 * Improved utilization of zero-displacement conditional branches. 5928 * The following deprecated options have been removed 5929 + -mcbranchdi 5930 + -mcmpeqdi 5931 + -minvalid-symbols 5932 + -msoft-atomic 5933 + -mspace 5934 + -madjust-unroll 5935 * Support for the following SH2A instructions has been added 5936 + mov.b @-Rm,R0 5937 + mov.w @-Rm,R0 5938 + mov.l @-Rm,R0 5939 + mov.b R0,@Rn+ 5940 + mov.w R0,@Rn+ 5941 + mov.l R0,@Rn+ 5942 5943 SPARC 5944 5945 * The SPARC port now uses LRA by default. 5946 * Support for the new Subtract-Extended-with-Carry instruction 5947 available in SPARC M7 (Niagara 7) has been added. 5948 5949 Operating Systems 5950 5951 AIX 5952 5953 * Visibility support has been enabled for AIX 7.1 and above. 5954 5955 Fuchsia 5956 5957 * Support has been added for the [19]Fuchsia OS. 5958 5959 RTEMS 5960 5961 * The ABI changes on ARM so that no short enums are used by default. 5962 5963 Other significant improvements 5964 5965 * -fverbose-asm previously emitted information on the meanings of 5966 assembly expressions. This has been extended so that it now also 5967 prints comments showing the source lines that correspond to the 5968 assembly, making it easier to read the generated assembly 5969 (especially with larger functions). For example, given this C 5970 source file: 5971 5972 int test (int n) 5973 { 5974 int i; 5975 int total = 0; 5976 5977 for (i = 0; i < n; i++) 5978 total += i * i; 5979 return total; 5980 } 5981 5982 -fverbose-asm now gives output similar to this for the function 5983 body (when compiling for x86_64, with -Os): 5984 5985 .text 5986 .globl test 5987 .type test, @@function 5988 test: 5989 .LFB0: 5990 .cfi_startproc 5991 # example.c:4: int total = 0; 5992 xorl %eax, %eax # <retval> 5993 # example.c:6: for (i = 0; i < n; i++) 5994 xorl %edx, %edx # i 5995 .L2: 5996 # example.c:6: for (i = 0; i < n; i++) 5997 cmpl %edi, %edx # n, i 5998 jge .L5 #, 5999 # example.c:7: total += i * i; 6000 movl %edx, %ecx # i, tmp92 6001 imull %edx, %ecx # i, tmp92 6002 # example.c:6: for (i = 0; i < n; i++) 6003 incl %edx # i 6004 # example.c:7: total += i * i; 6005 addl %ecx, %eax # tmp92, <retval> 6006 jmp .L2 # 6007 .L5: 6008 # example.c:10: } 6009 ret 6010 .cfi_endproc 6011 6012 * Two new options have been added for printing fix-it hints: 6013 + -fdiagnostics-parseable-fixits allows for fix-it hints to be 6014 emitted in a machine-readable form, suitable for consumption 6015 by IDEs. For example, given: 6016 6017 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 6018 you mean 'color'? 6019 return ptr->colour; 6020 ^~~~~~ 6021 color 6022 6023 it will emit: 6024 6025 fix-it:"spellcheck-fields.cc":{52:13-52:19}:"color" 6026 6027 + -fdiagnostics-generate-patch will print a patch in "unified" 6028 format after any diagnostics are printed, showing the result 6029 of applying all fix-it hints. For the above example it would 6030 emit: 6031 6032 --- spellcheck-fields.cc 6033 +++ spellcheck-fields.cc 6034 @@ -49,5 +49,5 @@ 6035 6036 color get_color(struct s *ptr) 6037 { 6038 - return ptr->colour; 6039 + return ptr->color; 6040 } 6041 6042 * The gcc and g++ driver programs will now provide suggestions for 6043 misspelled arguments to command-line options. 6044 6045 $ gcc -c test.c -ftls-model=global-dinamic 6046 gcc: error: unknown TLS model 'global-dinamic' 6047 gcc: note: valid arguments to '-ftls-model=' are: global-dynamic initial-exec lo 6048 cal-dynamic local-exec; did you mean 'global-dynamic'? 6049 6050 * The compiler will now provide suggestions for misspelled 6051 parameters. 6052 6053 $ gcc -c test.c --param max-early-inliner-iteration=3 6054 cc1: error: invalid --param name 'max-early-inliner-iteration'; did you mean 'ma 6055 x-early-inliner-iterations'? 6056 6057 * Profile-guided optimization (PGO) instrumentation, as well as test 6058 coverage (GCOV), can newly instrument constructors (functions marks 6059 with __attribute__((constructor))), destructors and C++ 6060 constructors (and destructors) of classes that are used as the type 6061 of a global variable. 6062 * A new option -fprofile-update=atomic prevents creation of corrupted 6063 profiles created during an instrumentation run (-fprofile=generate) 6064 of an application. The downside of the option is a speed penalty. 6065 Providing -pthread on the command line selects atomic profile 6066 updating (when supported by the target). 6067 * GCC's already extensive testsuite has gained some new capabilities, 6068 to further improve the reliability of the compiler: 6069 + GCC now has an internal unit-testing API and a suite of tests 6070 for programmatic self-testing of subsystems. 6071 + GCC's C front end has been extended so that it can parse dumps 6072 of GCC's internal representations, allowing for DejaGnu tests 6073 that more directly exercise specific optimization passes. This 6074 covers both the [20]GIMPLE representation (for testing 6075 higher-level optimizations) and the [21]RTL representation, 6076 allowing for more direct testing of lower-level details, such 6077 as register allocation and instruction selection. 6078 6079 GCC 7.1 6080 6081 This is the [22]list of problem reports (PRs) from GCC's bug tracking 6082 system that are known to be fixed in the 7.1 release. This list might 6083 not be complete (that is, it is possible that some PRs that have been 6084 fixed are not listed here). 6085 6086 GCC 7.2 6087 6088 This is the [23]list of problem reports (PRs) from GCC's bug tracking 6089 system that are known to be fixed in the 7.2 release. This list might 6090 not be complete (that is, it is possible that some PRs that have been 6091 fixed are not listed here). 6092 6093 Target Specific Changes 6094 6095 SPARC 6096 6097 * Support for the SPARC M8 processor has been added. 6098 * The switches -mfix-ut700 and -mfix-gr712rc have been added to work 6099 around an erratum in LEON3FT processors. 6100 * Use of the Floating-point Multiply Single to Double (FsMULd) 6101 instruction can now be controlled by the -mfsmuld and -fno-fsmuld 6102 options. 6103 6104 Operating Systems 6105 6106 RTEMS 6107 6108 * The Ada run-time support uses now thread-local storage (TLS). 6109 * Support for RISC-V has been added. 6110 * Support for 64-bit PowerPC using the ELFv2 ABI with 64-bit long 6111 double has been added. 6112 6113 GCC 7.3 6114 6115 This is the [24]list of problem reports (PRs) from GCC's bug tracking 6116 system that are known to be fixed in the 7.3 release. This list might 6117 not be complete (that is, it is possible that some PRs that have been 6118 fixed are not listed here). 6119 6120 Target Specific Changes 6121 6122 SPARC 6123 6124 * Workarounds for the four [25]LEON3FT errata GRLIB-TN-0010..0013 6125 have been added. Relevant errata are activated by the target 6126 specific -mfix-ut699, -mfix-ut700 and -mfix-gr712rc switches. 6127 6128 Operating Systems 6129 6130 RTEMS 6131 6132 * Support has been added for Epiphany target. 6133 6134 GCC 7.4 6135 6136 This is the [26]list of problem reports (PRs) from GCC's bug tracking 6137 system that are known to be fixed in the 7.4 release. This list might 6138 not be complete (that is, it is possible that some PRs that have been 6139 fixed are not listed here). 6140 6141 GCC 7.5 6142 6143 This is the [27]list of problem reports (PRs) from GCC's bug tracking 6144 system that are known to be fixed in the 7.5 release. This list might 6145 not be complete (that is, it is possible that some PRs that have been 6146 fixed are not listed here). 6147 6148 6149 For questions related to the use of GCC, please consult these web 6150 pages and the [28]GCC manuals. If that fails, the 6151 [29]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6152 web pages and the development of GCC are welcome on our developer 6153 list at [30]gcc (a] gcc.gnu.org. All of [31]our lists have public 6154 archives. 6155 6156 Copyright (C) [32]Free Software Foundation, Inc. Verbatim copying and 6157 distribution of this entire article is permitted in any medium, 6158 provided this notice is preserved. 6159 6160 These pages are [33]maintained by the GCC team. Last modified 6161 2022-10-26. 6162 6163 References 6164 6165 1. http://gcc.gnu.org/gcc-7/porting_to.html 6166 2. http://gcc.gnu.org/onlinedocs/index.html#current 6167 3. https://gcc.gnu.org/wiki/LRAIsDefault 6168 4. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/manual/profile_mode.html 6169 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728 6170 6. https://gcc.gnu.org/wiki/OpenACC 6171 7. https://gcc.gnu.org/wiki/Offloading 6172 8. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Object-Size-Checking.html 6173 9. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 6174 10. https://wg21.link/p0136 6175 11. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/using_dual_abi.html 6176 12. https://www.openmp.org/specifications/ 6177 13. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/jit/topics/expressions.html#gcc_jit_rvalue_set_bool_require_tail_call 6178 14. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AArch64-Options.html#AArch64-Options 6179 15. https://gcc.gnu.org/install/configure.html 6180 16. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Variable-Attributes.html 6181 17. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Built-in-Functions.html 6182 18. https://gcc.gnu.org/wiki/Offloading 6183 19. https://fuchsia.googlesource.com/ 6184 20. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/GIMPLE-Tests.html 6185 21. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/RTL-Tests.html 6186 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.0 6187 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.2 6188 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.3 6189 25. https://www.gaisler.com/index.php/information/app-tech-notes 6190 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.4 6191 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.5 6192 28. https://gcc.gnu.org/onlinedocs/ 6193 29. mailto:gcc-help (a] gcc.gnu.org 6194 30. mailto:gcc (a] gcc.gnu.org 6195 31. https://gcc.gnu.org/lists.html 6196 32. https://www.fsf.org/ 6197 33. https://gcc.gnu.org/about.html 6198 ====================================================================== 6199 http://gcc.gnu.org/gcc-6/index.html 6200 6201 GCC 6 Release Series 6202 6203 (This release series is no longer supported.) 6204 6205 October 26, 2018 6206 6207 The [1]GNU project and the GCC developers are pleased to announce the 6208 release of GCC 6.5. 6209 6210 This release is a bug-fix release, containing fixes for regressions in 6211 GCC 6.4 relative to previous releases of GCC. 6212 6213 Release History 6214 6215 GCC 6.5 6216 October 26, 2018 ([2]changes, [3]documentation) 6217 6218 GCC 6.4 6219 July 4, 2017 ([4]changes, [5]documentation) 6220 6221 GCC 6.3 6222 December 21, 2016 ([6]changes, [7]documentation) 6223 6224 GCC 6.2 6225 August 22, 2016 ([8]changes, [9]documentation) 6226 6227 GCC 6.1 6228 April 27, 2016 ([10]changes, [11]documentation) 6229 6230 References and Acknowledgements 6231 6232 GCC used to stand for the GNU C Compiler, but since the compiler 6233 supports several other languages aside from C, it now stands for the 6234 GNU Compiler Collection. 6235 6236 A list of [12]successful builds is updated as new information becomes 6237 available. 6238 6239 The GCC developers would like to thank the numerous people that have 6240 contributed new features, improvements, bug fixes, and other changes as 6241 well as test results to GCC. This [13]amazing group of volunteers is 6242 what makes GCC successful. 6243 6244 For additional information about GCC please refer to the [14]GCC 6245 project web site or contact the [15]GCC development mailing list. 6246 6247 To obtain GCC please use [16]our mirror sites or [17]our version 6248 control system. 6249 6250 6251 For questions related to the use of GCC, please consult these web 6252 pages and the [18]GCC manuals. If that fails, the 6253 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6254 web pages and the development of GCC are welcome on our developer 6255 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 6256 archives. 6257 6258 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 6259 distribution of this entire article is permitted in any medium, 6260 provided this notice is preserved. 6261 6262 These pages are [23]maintained by the GCC team. Last modified 6263 2022-10-26. 6264 6265 References 6266 6267 1. http://www.gnu.org/ 6268 2. http://gcc.gnu.org/gcc-6/changes.html 6269 3. http://gcc.gnu.org/onlinedocs/6.5.0/ 6270 4. http://gcc.gnu.org/gcc-6/changes.html 6271 5. http://gcc.gnu.org/onlinedocs/6.4.0/ 6272 6. http://gcc.gnu.org/gcc-6/changes.html 6273 7. http://gcc.gnu.org/onlinedocs/6.3.0/ 6274 8. http://gcc.gnu.org/gcc-6/changes.html 6275 9. http://gcc.gnu.org/onlinedocs/6.2.0/ 6276 10. http://gcc.gnu.org/gcc-6/changes.html 6277 11. http://gcc.gnu.org/onlinedocs/6.1.0/ 6278 12. http://gcc.gnu.org/gcc-6/buildstat.html 6279 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 6280 14. http://gcc.gnu.org/index.html 6281 15. mailto:gcc (a] gcc.gnu.org 6282 16. http://gcc.gnu.org/mirrors.html 6283 17. http://gcc.gnu.org/git.html 6284 18. https://gcc.gnu.org/onlinedocs/ 6285 19. mailto:gcc-help (a] gcc.gnu.org 6286 20. mailto:gcc (a] gcc.gnu.org 6287 21. https://gcc.gnu.org/lists.html 6288 22. https://www.fsf.org/ 6289 23. https://gcc.gnu.org/about.html 6290 ====================================================================== 6291 http://gcc.gnu.org/gcc-6/changes.html 6292 6293 GCC 6 Release Series 6294 Changes, New Features, and Fixes 6295 6296 This page is a brief summary of some of the huge number of improvements 6297 in GCC 6. For more information, see the [1]Porting to GCC 6 page and 6298 the [2]full GCC documentation. 6299 6300 Caveats 6301 6302 * The default mode for C++ is now -std=gnu++14 instead of 6303 -std=gnu++98. 6304 * Support for a number of older systems and recently unmaintained or 6305 untested target ports of GCC has been declared obsolete in GCC 6. 6306 Unless there is activity to revive them, the next release of GCC 6307 will have their sources permanently removed. 6308 The following ports for individual systems on particular 6309 architectures have been obsoleted: 6310 + SH5 / SH64 (sh64-*-*) as announced [3]here. 6311 * The AVR port requires binutils version 2.26.1 or later for the fix 6312 for [4]PR71151 to work. 6313 * The GCC 6.5 release has an accidental ABI incompatibility for 6314 nested std::pair objects, for more details see [5]PR 87822. The bug 6315 causes a layout change for pairs where the first member is also a 6316 pair, e.g. std::pair<std::pair<X, Y>, Z>. The GCC 6 release series 6317 is closed so the bug in GCC 6.5 will not be fixed upstream, but 6318 there is a patch in the bug report to allow it to be fixed by 6319 anybody packaging GCC 6.5 or installing it themselves. 6320 6321 General Optimizer Improvements 6322 6323 * UndefinedBehaviorSanitizer gained a new sanitization option, 6324 -fsanitize=bounds-strict, which enables strict checking of array 6325 bounds. In particular, it enables -fsanitize=bounds as well as 6326 instrumentation of flexible array member-like arrays. 6327 * Type-based alias analysis now disambiguates accesses to different 6328 pointers. This improves precision of the alias oracle by about 6329 20-30% on higher-level C++ programs. Programs doing invalid type 6330 punning of pointer types may now need -fno-strict-aliasing to work 6331 correctly. 6332 * Alias analysis now correctly supports the weakref and alias 6333 attributes. This allows accessing both a variable and its alias in 6334 one translation unit which is common with link-time optimization. 6335 * Value range propagation now assumes that the this pointer in C++ 6336 member functions is non-null. This eliminates common null pointer 6337 checks but also breaks some non-conforming code-bases (such as 6338 Qt-5, Chromium, KDevelop). As a temporary work-around 6339 -fno-delete-null-pointer-checks can be used. Wrong code can be 6340 identified by using -fsanitize=undefined. 6341 * Link-time optimization improvements: 6342 + warning and error attributes are now correctly preserved by 6343 declaration linking and thus -D_FORTIFY_SOURCE=2 is now 6344 supported with -flto. 6345 + Type merging was fixed to handle C and Fortran 6346 interoperability rules as defined by the Fortran 2008 language 6347 standard. 6348 As an exception, CHARACTER(KIND=C_CHAR) is not inter-operable 6349 with char in all cases because it is an array while char is 6350 scalar. INTEGER(KIND=C_SIGNED_CHAR) should be used instead. In 6351 general, this inter-operability cannot be implemented, for 6352 example on targets where the argument passing convention for 6353 arrays differs from scalars. 6354 + More type information is now preserved at link time, reducing 6355 the loss of accuracy of the type-based alias analysis compared 6356 to builds without link-time optimization. 6357 + Invalid type punning on global variables and declarations is 6358 now reported with -Wodr-type-mismatch. 6359 + The size of LTO object files was reduced by about 11% 6360 (measured by compiling Firefox 46.0). 6361 + Link-time parallelization (enabled using -flto=n) was 6362 significantly improved by decreasing the size of streamed data 6363 when partitioning programs. The size of streamed IL while 6364 compiling Firefox 46.0 was reduced by 66%. 6365 + The linker plugin was extended to pass information about the 6366 type of binary produced to the GCC back end. (That can also be 6367 controlled manually by -flinker-output.) This makes it 6368 possible to properly configure the code generator and support 6369 incremental linking. Incremental linking of LTO objects by gcc 6370 -r is now supported for plugin-enabled setups. 6371 There are two ways to perform incremental linking: 6372 1. Linking by ld -r will result in an object file with all 6373 sections from individual object files mechanically 6374 merged. This delays the actual link-time optimization to 6375 the final linking step and thus permits whole program 6376 optimization. Linking the final binary with such object 6377 files is however slower. 6378 2. Linking by gcc -r will lead to link-time optimization and 6379 emit the final binary into the object file. Linking such 6380 an object file is fast but avoids any benefits from whole 6381 program optimization. 6382 GCC 7 will support incremental link-time optimization with gcc 6383 -r. 6384 * Inter-procedural optimization improvements: 6385 + Basic jump threading is now performed before profile 6386 construction and inline analysis, resulting in more realistic 6387 size and time estimates that drive the heuristics of the 6388 inliner and function cloning passes. 6389 + Function cloning now more aggressively eliminates unused 6390 function parameters. 6391 6392 New Languages and Language specific improvements 6393 6394 Compared to GCC 5, the GCC 6 release series includes a much improved 6395 implementation of the [6]OpenACC 2.0a specification. Highlights are: 6396 * In addition to single-threaded host-fallback execution, offloading 6397 is supported for nvptx (Nvidia GPUs) on x86_64 and PowerPC 64-bit 6398 little-endian GNU/Linux host systems. For nvptx offloading, with 6399 the OpenACC parallel construct, the execution model allows for an 6400 arbitrary number of gangs, up to 32 workers, and 32 vectors. 6401 * Initial support for parallelized execution of OpenACC kernels 6402 constructs: 6403 + Parallelization of a kernels region is switched on by 6404 -fopenacc combined with -O2 or higher. 6405 + Code is offloaded onto multiple gangs, but executes with just 6406 one worker, and a vector length of 1. 6407 + Directives inside a kernels region are not supported. 6408 + Loops with reductions can be parallelized. 6409 + Only kernels regions with one loop nest are parallelized. 6410 + Only the outer-most loop of a loop nest can be parallelized. 6411 + Loop nests containing sibling loops are not parallelized. 6412 Typically, using the OpenACC parallel construct gives much better 6413 performance, compared to the initial support of the OpenACC kernels 6414 construct. 6415 * The device_type clause is not supported. The bind and nohost 6416 clauses are not supported. The host_data directive is not supported 6417 in Fortran. 6418 * Nested parallelism (cf. CUDA dynamic parallelism) is not supported. 6419 * Usage of OpenACC constructs inside multithreaded contexts (such as 6420 created by OpenMP, or pthread programming) is not supported. 6421 * If a call to the acc_on_device function has a compile-time constant 6422 argument, the function call evaluates to a compile-time constant 6423 value only for C and C++ but not for Fortran. 6424 6425 See the [7]OpenACC and [8]Offloading wiki pages for further 6426 information. 6427 6428 C family 6429 6430 * Version 4.5 of the [9]OpenMP specification is now supported in the 6431 C and C++ compilers. 6432 * The C and C++ compilers now support attributes on enumerators. For 6433 instance, it is now possible to mark enumerators as deprecated: 6434 6435 enum { 6436 newval, 6437 oldval __attribute__ ((deprecated ("too old"))) 6438 }; 6439 6440 * Source locations for the C and C++ compilers are now tracked as 6441 ranges, rather than just points, making it easier to identify the 6442 subexpression of interest within a complicated expression. For 6443 example: 6444 6445 test.cc: In function 'int test(int, int, foo, int, int)': 6446 test.cc:5:16: error: no match for 'operator*' (operand types are 'int' and 'foo' 6447 ) 6448 return p + q * r * s + t; 6449 ~~^~~ 6450 6451 In addition, there is now initial support for precise diagnostic 6452 locations within strings: 6453 6454 format-strings.c:3:14: warning: field width specifier '*' expects a matching 'in 6455 t' argument [-Wformat=] 6456 printf("%*d"); 6457 ^ 6458 6459 * Diagnostics can now contain "fix-it hints", which are displayed in 6460 context underneath the relevant source code. For example: 6461 6462 fixits.c: In function 'bad_deref': 6463 fixits.c:11:13: error: 'ptr' is a pointer; did you mean to use '->'? 6464 return ptr.x; 6465 ^ 6466 -> 6467 6468 * The C and C++ compilers now offer suggestions for misspelled field 6469 names: 6470 6471 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 6472 you mean 'color'? 6473 return ptr->colour; 6474 ^~~~~~ 6475 6476 * New command-line options have been added for the C and C++ 6477 compilers: 6478 + -Wshift-negative-value warns about left shifting a negative 6479 value. 6480 + -Wshift-overflow warns about left shift overflows. This 6481 warning is enabled by default. -Wshift-overflow=2 also warns 6482 about left-shifting 1 into the sign bit. 6483 + -Wtautological-compare warns if a self-comparison always 6484 evaluates to true or false. This warning is enabled by -Wall. 6485 + -Wnull-dereference warns if the compiler detects paths that 6486 trigger erroneous or undefined behavior due to dereferencing a 6487 null pointer. This option is only active when 6488 -fdelete-null-pointer-checks is active, which is enabled by 6489 optimizations in most targets. The precision of the warnings 6490 depends on the optimization options used. 6491 + -Wduplicated-cond warns about duplicated conditions in an 6492 if-else-if chain. 6493 + -Wmisleading-indentation warns about places where the 6494 indentation of the code gives a misleading idea of the block 6495 structure of the code to a human reader. For example, given 6496 [10]CVE-2014-1266: 6497 6498 sslKeyExchange.c: In function 'SSLVerifySignedServerKeyExchange': 6499 sslKeyExchange.c:629:3: warning: this 'if' clause does not guard... [-Wmisleadin 6500 g-indentation] 6501 if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0) 6502 ^~ 6503 sslKeyExchange.c:631:5: note: ...this statement, but the latter is misleadingly 6504 indented as if it is guarded by the 'if' 6505 goto fail; 6506 ^~~~ 6507 6508 This warning is enabled by -Wall. 6509 * The C and C++ compilers now emit saner error messages if 6510 merge-conflict markers are present in a source file. 6511 6512 test.c:3:1: error: version control conflict marker in file 6513 <<<<<<< HEAD 6514 ^~~~~~~ 6515 6516 C 6517 6518 * It is possible to disable warnings when an initialized field of a 6519 structure or a union with side effects is being overridden when 6520 using designated initializers via a new warning option 6521 -Woverride-init-side-effects. 6522 * A new type attribute scalar_storage_order applying to structures 6523 and unions has been introduced. It specifies the storage order (aka 6524 endianness) in memory of scalar fields in structures or unions. 6525 6526 C++ 6527 6528 * The default mode has been changed to -std=gnu++14. 6529 * [11]C++ Concepts are now supported when compiling with -fconcepts. 6530 * -flifetime-dse is more aggressive in dead-store elimination in 6531 situations where a memory store to a location precedes a 6532 constructor to that memory location. 6533 * G++ now supports [12]C++17 fold expressions, u8 character literals, 6534 extended static_assert, and nested namespace definitions. 6535 * G++ now allows constant evaluation for all non-type template 6536 arguments. 6537 * G++ now supports C++ Transactional Memory when compiling with 6538 -fgnu-tm. 6539 6540 Runtime Library (libstdc++) 6541 6542 * Extensions to the C++ Library to support mathematical special 6543 functions (ISO/IEC 29124:2010), thanks to Edward Smith-Rowland. 6544 * Experimental support for C++17, including the following new 6545 features: 6546 + std::uncaught_exceptions function (this is also available for 6547 -std=gnu++NN modes); 6548 + new member functions try_emplace and insert_or_assign for 6549 unique_key maps; 6550 + non-member functions std::size, std::empty, and std::data for 6551 accessing containers and arrays; 6552 + std::invoke; 6553 + std::shared_mutex; 6554 + std::void_t and std::bool_constant metaprogramming utilities. 6555 Thanks to Ville Voutilainen for contributing many of the C++17 6556 features. 6557 * An experimental implementation of the File System TS. 6558 * Experimental support for most features of the second version of the 6559 Library Fundamentals TS. This includes polymorphic memory resources 6560 and array support in shared_ptr, thanks to Fan You. 6561 * Some assertions checked by Debug Mode can now also be enabled by 6562 _GLIBCXX_ASSERTIONS. The subset of checks enabled by the new macro 6563 have less run-time overhead than the full _GLIBCXX_DEBUG checks and 6564 don't affect the library ABI, so can be enabled per-translation 6565 unit. 6566 * Timed mutex types are supported on more targets, including Darwin. 6567 * Improved std::locale support for DragonFly and FreeBSD, thanks to 6568 John Marino and Andreas Tobler. 6569 6570 Fortran 6571 6572 * Fortran 2008 SUBMODULE support. 6573 * Fortran 2015 EVENT_TYPE, EVENT_POST, EVENT_WAIT, and EVENT_QUERY 6574 support. 6575 * Improved support for Fortran 2003 deferred-length character 6576 variables. 6577 * Improved support for OpenMP and OpenACC. 6578 * The MATMUL intrinsic is now inlined for straightforward cases if 6579 front-end optimization is active. The maximum size for inlining can 6580 be set to n with the -finline-matmul-limit=n option and turned off 6581 with -finline-matmul-limit=0. 6582 * The -Wconversion-extra option will warn about REAL constants which 6583 have excess precision for their kind. 6584 * The -Winteger-division option has been added, which warns about 6585 divisions of integer constants which are truncated. This option is 6586 included in -Wall by default. 6587 6588 libgccjit 6589 6590 * The driver code is now run in-process within libgccjit, providing a 6591 small speed-up of the compilation process. 6592 * The API has gained entrypoints for 6593 + [13]timing how long was spent in different parts of code, 6594 + [14]creating switch statements, 6595 + [15]allowing unreachable basic blocks in a function, and 6596 + [16]adding arbitrary command-line options to a compilation. 6597 6598 New Targets and Target Specific Improvements 6599 6600 AArch64 6601 6602 * A number of AArch64-specific options have been added. The most 6603 important ones are summarised in this section; for more detailed 6604 information please refer to the documentation. 6605 * The command-line options -march=native, -mcpu=native and 6606 -mtune=native are now available on native AArch64 GNU/Linux 6607 systems. Specifying these options causes GCC to auto-detect the 6608 host CPU and choose the optimal setting for that system. 6609 * -fpic is now supported when generating code for the small code 6610 model (-mcmodel=small). The size of the global offset table (GOT) 6611 is limited to 28KiB under the LP64 SysV ABI, and 15KiB under the 6612 ILP32 SysV ABI. 6613 * The AArch64 port now supports target attributes and pragmas. Please 6614 refer to the [17]documentation for details of available attributes 6615 and pragmas as well as usage instructions. 6616 * Link-time optimization across translation units with different 6617 target-specific options is now supported. 6618 * The option -mtls-size= is now supported. It can be used to specify 6619 the bit size of TLS offsets, allowing GCC to generate better TLS 6620 instruction sequences. 6621 * The option -fno-plt is now fully functional. 6622 * The ARMv8.1-A architecture and the Large System Extensions are now 6623 supported. They can be used by specifying the -march=armv8.1-a 6624 option. Additionally, the +lse option extension can be used in a 6625 similar fashion to other option extensions. The Large System 6626 Extensions introduce new instructions that are used in the 6627 implementation of atomic operations. 6628 * The ACLE half-precision floating-point type __fp16 is now supported 6629 in the C and C++ languages. 6630 * The ARM Cortex-A35 processor is now supported via the 6631 -mcpu=cortex-a35 and -mtune=cortex-a35 options as well as the 6632 equivalent target attributes and pragmas. 6633 * The Qualcomm QDF24xx processor is now supported via the 6634 -mcpu=qdf24xx and -mtune=qdf24xx options as well as the equivalent 6635 target attributes and pragmas. 6636 * Code generation for the ARM Cortex-A57 processor is improved. Among 6637 general code generation improvements, a better algorithm is added 6638 for allocating registers to floating-point multiply-accumulate 6639 instructions offering increased performance when compiling with 6640 -mcpu=cortex-a57 or -mtune=cortex-a57. 6641 * Code generation for the ARM Cortex-A53 processor is improved. A 6642 more accurate instruction scheduling model for the processor is now 6643 used, and a number of compiler tuning parameters have been set to 6644 offer increased performance when compiling with -mcpu=cortex-a53 or 6645 -mtune=cortex-a53. 6646 * Code generation for the Samsung Exynos M1 processor is improved. A 6647 more accurate instruction scheduling model for the processor is now 6648 used, and a number of compiler tuning parameters have been set to 6649 offer increased performance when compiling with -mcpu=exynos-m1 or 6650 -mtune=exynos-m1. 6651 * Improvements in the generation of conditional branches and literal 6652 pools allow the compiler to compile functions of a large size. 6653 Constant pools are now placed into separate rodata sections. The 6654 new option -mpc-relative-literal-loads generates per-function 6655 literal pools, limiting the maximum size of functions to 1MiB. 6656 * Several correctness issues generating Advanced SIMD instructions 6657 for big-endian targets have been fixed resulting in improved code 6658 generation for ACLE intrinsics with -mbig-endian. 6659 6660 ARM 6661 6662 * Support for revisions of the ARM architecture prior to ARMv4t has 6663 been deprecated and will be removed in a future GCC release. The 6664 -mcpu and -mtune values that are deprecated are: arm2, arm250, 6665 arm3, arm6, arm60, arm600, arm610, arm620, arm7, arm7d, arm7di, 6666 arm70, arm700, arm700i, arm710, arm720, arm710c, arm7100, arm7500, 6667 arm7500fe, arm7m, arm7dm, arm7dmi, arm8, arm810, strongarm, 6668 strongarm110, strongarm1100, strongarm1110, fa526, fa626. The value 6669 arm7tdmi is still supported. The values of -march that are 6670 deprecated are: armv2,armv2a,armv3,armv3m,armv4. 6671 * The ARM port now supports target attributes and pragmas. Please 6672 refer to the [18]documentation for details of available attributes 6673 and pragmas as well as usage instructions. 6674 * Support has been added for the following processors (GCC 6675 identifiers in parentheses): ARM Cortex-A32 (cortex-a32), ARM 6676 Cortex-A35 (cortex-a35) and ARM Cortex-R8 (cortex-r8). The GCC 6677 identifiers can be used as arguments to the -mcpu or -mtune 6678 options, for example: -mcpu=cortex-a32 or -mtune=cortex-a35. 6679 6680 Heterogeneous Systems Architecture 6681 6682 * GCC can now generate HSAIL (Heterogeneous System Architecture 6683 Intermediate Language) for simple OpenMP device constructs if 6684 configured with --enable-offload-targets=hsa. A new libgomp plugin 6685 then runs the HSA GPU kernels implementing these constructs on HSA 6686 capable GPUs via a standard HSA run time. 6687 If the HSA compilation back end determines it cannot output HSAIL 6688 for a particular input, it gives a warning by default. These 6689 warnings can be suppressed with -Wno-hsa. To give a few examples, 6690 the HSA back end does not implement compilation of code using 6691 function pointers, automatic allocation of variable sized arrays, 6692 functions with variadic arguments as well as a number of other less 6693 common programming constructs. 6694 When compilation for HSA is enabled, the compiler attempts to 6695 compile composite OpenMP constructs 6696 6697 #pragma omp target teams distribute parallel for 6698 6699 into parallel HSA GPU kernels. 6700 6701 IA-32/x86-64 6702 6703 * GCC now supports the Intel CPU named Skylake with AVX-512 6704 extensions through -march=skylake-avx512. The switch enables the 6705 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 6706 AVX-512DQ. 6707 * Support for new AMD instructions monitorx and mwaitx has been 6708 added. This includes new intrinsic and built-in support. It is 6709 enabled through option -mmwaitx. The instructions monitorx and 6710 mwaitx implement the same functionality as the old monitor and 6711 mwait instructions. In addition, mwaitx adds a configurable timer. 6712 The timer value is received as third argument and stored in 6713 register %ebx. 6714 * x86-64 targets now allow stack realignment from a word-aligned 6715 stack pointer using the command-line option -mstackrealign or 6716 __attribute__ ((force_align_arg_pointer)). This allows functions 6717 compiled with a vector-aligned stack to be invoked from objects 6718 that keep only word-alignment. 6719 * Support for address spaces __seg_fs, __seg_gs, and __seg_tls. These 6720 can be used to access data via the %fs and %gs segments without 6721 having to resort to inline assembly. Please refer to the 6722 [19]documentation for usage instructions. 6723 * Support for AMD Zen (family 17h) processors is now available 6724 through the -march=znver1 and -mtune=znver1 options. 6725 6726 MeP 6727 6728 * Support for the MeP (mep-elf) architecture has been deprecated and 6729 will be removed in a future GCC release. 6730 6731 MSP430 6732 6733 * The MSP430 compiler now has the ability to automatically distribute 6734 code and data between low memory (addresses below 64K) and high 6735 memory. This only applies to parts that actually have both memory 6736 regions and only if the linker script for the part has been 6737 specifically set up to support this feature. 6738 A new attribute of either can be applied to both functions and 6739 data, and this tells the compiler to place the object into low 6740 memory if there is room and into high memory otherwise. Two other 6741 new attributes - lower and upper - can be used to explicitly state 6742 that an object should be placed in the specified memory region. If 6743 there is not enough left in that region the compilation will fail. 6744 Two new command-line options - -mcode-region=[lower|upper|either] 6745 and -mdata-region=[lower|upper|either] - can be used to tell the 6746 compiler what to do with objects that do not have one of these new 6747 attributes. 6748 6749 PowerPC / PowerPC64 / RS6000 6750 6751 * PowerPC64 now supports IEEE 128-bit floating-point using the 6752 __float128 data type. In GCC 6, this is not enabled by default, but 6753 you can enable it with -mfloat128. The IEEE 128-bit floating-point 6754 support requires the use of the VSX instruction set. IEEE 128-bit 6755 floating-point values are passed and returned as a single vector 6756 value. The software emulator for IEEE 128-bit floating-point 6757 support is only built on PowerPC GNU/Linux systems where the 6758 default CPU is at least power7. On future ISA 3.0 systems (POWER 9 6759 and later), you will be able to use the -mfloat128-hardware option 6760 to use the ISA 3.0 instructions that support IEEE 128-bit 6761 floating-point. An additional type (__ibm128) has been added to 6762 refer to the IBM extended double type that normally implements long 6763 double. This will allow for a future transition to implementing 6764 long double with IEEE 128-bit floating-point. 6765 * Basic support has been added for POWER9 hardware that will use the 6766 recently published OpenPOWER ISA 3.0 instructions. The following 6767 new switches are available: 6768 + -mcpu=power9: Implement all of the ISA 3.0 instructions 6769 supported by the compiler. 6770 + -mtune=power9: In the future, apply tuning for POWER9 systems. 6771 Currently, POWER8 tunings are used. 6772 + -mmodulo: Generate code using the ISA 3.0 integer instructions 6773 (modulus, count trailing zeros, array index support, integer 6774 multiply/add). 6775 + -mpower9-fusion: Generate code to suitably fuse instruction 6776 sequences for a POWER9 system. 6777 + -mpower9-dform: Generate code to use the new D-form 6778 (register+offset) memory instructions for the vector 6779 registers. 6780 + -mpower9-vector: Generate code using the new ISA 3.0 vector 6781 (VSX or Altivec) instructions. 6782 + -mpower9-minmax: Reserved for future development. 6783 + -mtoc-fusion: Keep TOC entries together to provide more fusion 6784 opportunities. 6785 * New constraints have been added to support IEEE 128-bit 6786 floating-point and ISA 3.0 instructions: 6787 + wb: Altivec register if -mpower9-dform is enabled. 6788 + we: VSX register if -mpower9-vector is enabled for 64-bit code 6789 generation. 6790 + wo: VSX register if -mpower9-vector is enabled. 6791 + wp: Reserved for future use if long double is implemented with 6792 IEEE 128-bit floating-point instead of IBM extended double. 6793 + wq: VSX register if -mfloat128 is enabled. 6794 + wF: Memory operand suitable for POWER9 fusion load/store. 6795 + wG: Memory operand suitable for TOC fusion memory references. 6796 + wL: Integer constant identifying the element number mfvsrld 6797 accesses within a vector. 6798 * Support has been added for __builtin_cpu_is() and 6799 __builtin_cpu_supports(), allowing for very fast access to 6800 AT_PLATFORM, AT_HWCAP, and AT_HWCAP2 values. This requires use of 6801 glibc 2.23 or later. 6802 * All hardware transactional memory builtins now correctly behave as 6803 memory barriers. Programmers can use #ifdef __TM_FENCE__ to 6804 determine whether their "old" compiler treats the builtins as 6805 barriers. 6806 * Split-stack support has been added for gccgo on PowerPC64 for both 6807 big- and little-endian (but not for 32-bit). The gold linker from 6808 at least binutils 2.25.1 must be available in the PATH when 6809 configuring and building gccgo to enable split stack. (The 6810 requirement for binutils 2.25.1 applies to PowerPC64 only.) The 6811 split-stack feature allows a small initial stack size to be 6812 allocated for each goroutine, which increases as needed. 6813 * GCC on PowerPC now supports the standard lround function. 6814 * A new configuration option ---with-advance-toolchain=at was added 6815 for PowerPC 64-bit GNU/Linux systems to use the header files, 6816 library files, and the dynamic linker from a specific Advance 6817 Toolchain release instead of the default versions that are provided 6818 by the GNU/Linux distribution. In general, this option is intended 6819 for the developers of GCC, and it is not intended for general use. 6820 * The "q", "S", "T", and "t" asm-constraints have been removed. 6821 * The "b", "B", "m", "M", and "W" format modifiers have been removed. 6822 6823 S/390, System z, IBM z Systems 6824 6825 * Support for the IBM z13 processor has been added. When using the 6826 -march=z13 option, the compiler will generate code making use of 6827 the new instructions and registers introduced with the vector 6828 extension facility. The -mtune=z13 option enables z13 specific 6829 instruction scheduling without making use of new instructions. 6830 Compiling code with -march=z13 reduces the default alignment of 6831 vector types bigger than 8 bytes to 8. This is an ABI change and 6832 care must be taken when linking modules compiled with different 6833 arch levels which interchange variables containing vector type 6834 values. For newly compiled code the GNU linker will emit a warning. 6835 * The -mzvector option enables a C/C++ language extension. This 6836 extension provides a new keyword vector which can be used to define 6837 vector type variables. (Note: This is not available when enforcing 6838 strict standard compliance e.g. with -std=c99. Either enable GNU 6839 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 6840 Additionally a set of overloaded builtins is provided which is 6841 partially compatible to the PowerPC Altivec builtins. In order to 6842 make use of these builtins the vecintrin.h header file needs to be 6843 included. 6844 * The new command-line options -march=native, and -mtune=native are 6845 now available on native IBM z Systems. Specifying these options 6846 causes GCC to auto-detect the host CPU and choose the optimal 6847 setting for that system. If GCC is unable to detect the host CPU 6848 these options have no effect. 6849 * The IBM z Systems port now supports target attributes and pragmas. 6850 Please refer to the [20]documentation for details of available 6851 attributes and pragmas as well as usage instructions. 6852 * -fsplit-stack is now supported as part of the IBM z Systems port. 6853 This feature requires a recent gold linker to be used. 6854 * Support for the g5 and g6 -march=/-mtune= CPU level switches has 6855 been deprecated and will be removed in a future GCC release. -m31 6856 from now on defaults to -march=z900 if not specified otherwise. 6857 -march=native on a g5/g6 machine will default to -march=z900. 6858 6859 SH 6860 6861 * Support for SH5 / SH64 has been declared obsolete and will be 6862 removed in future releases. 6863 * Support for the FDPIC ABI has been added. It can be enabled using 6864 the new -mfdpic target option and --enable-fdpic configure option. 6865 6866 SPARC 6867 6868 * An ABI bug has been fixed in 64-bit mode. Unfortunately, this 6869 change will break binary compatibility with earlier releases for 6870 code it affects, but this should be pretty rare in practice. The 6871 conditions are: a 16-byte structure containing a double or a 8-byte 6872 vector in the second half is passed to a subprogram in slot #15, 6873 for example as 16th parameter if the first 15 ones have at most 8 6874 bytes. The double or vector was wrongly passed in floating-point 6875 register %d32 in lieu of on the stack as per the SPARC calling 6876 conventions. 6877 6878 Operating Systems 6879 6880 AIX 6881 6882 * DWARF debugging support for AIX 7.1 has been enabled as an optional 6883 debugging format. A more recent Technology Level (TL) and GCC built 6884 with that level are required for full exploitation of DWARF 6885 debugging capabilities. 6886 6887 Linux 6888 6889 * Support for the [21]musl C library was added for the AArch64, ARM, 6890 MicroBlaze, MIPS, MIPS64, PowerPC, PowerPC64, SH, i386, x32 and 6891 x86_64 targets. It can be selected using the new -mmusl option in 6892 case musl is not the default libc. GCC defaults to musl libc if it 6893 is built with a target triplet matching the *-linux-musl* pattern. 6894 6895 RTEMS 6896 6897 * The RTEMS thread model implementation changed. Mutexes now use 6898 self-contained objects defined in newlib <sys/lock.h> instead of 6899 Classic API semaphores. The keys for thread specific data and the 6900 once function are directly defined via <pthread.h>. Self-contained 6901 condition variables are provided via newlib <sys/lock.h>. The RTEMS 6902 thread model also supports C++11 threads. 6903 * OpenMP support now uses self-contained objects provided by newlib 6904 <sys/lock.h> and offers a significantly better performance compared 6905 to the POSIX configuration of libgomp. It is possible to configure 6906 thread pools for each scheduler instance via the environment 6907 variable GOMP_RTEMS_THREAD_POOLS. 6908 6909 Solaris 6910 6911 * Solaris 12 is now fully supported. Minimal support had already been 6912 present in GCC 5.3. 6913 * Solaris 12 provides a full set of startup files (crt1.o, crti.o, 6914 crtn.o), which GCC now prefers over its own ones. 6915 * Position independent executables (PIE) are now supported on Solaris 6916 12. 6917 * Constructor priority is now supported on Solaris 12 with the system 6918 linker. 6919 * libvtv has been ported to Solaris 11 and up. 6920 6921 Windows 6922 6923 * The option -mstackrealign is now automatically activated in 32-bit 6924 mode whenever the use of SSE instructions is requested. 6925 6926 Other significant improvements 6927 6928 * The gcc and g++ driver programs will now provide suggestions for 6929 misspelled command-line options. 6930 6931 $ gcc -static-libfortran test.f95 6932 gcc: error: unrecognized command line option '-static-libfortran'; did you mean 6933 '-static-libgfortran'? 6934 6935 * The --enable-default-pie configure option enables generation of PIE 6936 by default. 6937 6938 GCC 6.2 6939 6940 This is the [22]list of problem reports (PRs) from GCC's bug tracking 6941 system that are known to be fixed in the 6.2 release. This list might 6942 not be complete (that is, it is possible that some PRs that have been 6943 fixed are not listed here). 6944 6945 Target Specific Changes 6946 6947 SPARC 6948 6949 * Support for --with-cpu-32 and --with-cpu-64 configure options has 6950 been added on bi-architecture platforms. 6951 * Support for the SPARC M7 (Niagara 7) processor has been added. 6952 * Support for the VIS 4.0 instruction set has been added. 6953 6954 GCC 6.3 6955 6956 This is the [23]list of problem reports (PRs) from GCC's bug tracking 6957 system that are known to be fixed in the 6.3 release. This list might 6958 not be complete (that is, it is possible that some PRs that have been 6959 fixed are not listed here). 6960 6961 Target Specific Changes 6962 6963 IA-32/x86-64 6964 6965 * Support for the [24]deprecated pcommit instruction has been 6966 removed. 6967 6968 GCC 6.4 6969 6970 This is the [25]list of problem reports (PRs) from GCC's bug tracking 6971 system that are known to be fixed in the 6.4 release. This list might 6972 not be complete (that is, it is possible that some PRs that have been 6973 fixed are not listed here). 6974 6975 Operating Systems 6976 6977 RTEMS 6978 6979 * The ABI changes on ARM so that no short enums are used by default. 6980 6981 GCC 6.5 6982 6983 This is the [26]list of problem reports (PRs) from GCC's bug tracking 6984 system that are known to be fixed in the 6.5 release. This list might 6985 not be complete (that is, it is possible that some PRs that have been 6986 fixed are not listed here). 6987 6988 6989 For questions related to the use of GCC, please consult these web 6990 pages and the [27]GCC manuals. If that fails, the 6991 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6992 web pages and the development of GCC are welcome on our developer 6993 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 6994 archives. 6995 6996 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 6997 distribution of this entire article is permitted in any medium, 6998 provided this notice is preserved. 6999 7000 These pages are [32]maintained by the GCC team. Last modified 7001 2023-02-20. 7002 7003 References 7004 7005 1. http://gcc.gnu.org/gcc-6/porting_to.html 7006 2. http://gcc.gnu.org/onlinedocs/index.html#current 7007 3. https://gcc.gnu.org/ml/gcc/2015-08/msg00101.html 7008 4. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71151 7009 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87822 7010 6. https://www.openacc.org/ 7011 7. https://gcc.gnu.org/wiki/OpenACC 7012 8. https://gcc.gnu.org/wiki/Offloading 7013 9. https://www.openmp.org/specifications/ 7014 10. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1266 7015 11. https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4377.pdf 7016 12. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 7017 13. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/performance.html 7018 14. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/functions.html#gcc_jit_block_end_with_switch 7019 15. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_set_bool_allow_unreachable_blocks 7020 16. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_add_command_line_option 7021 17. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/AArch64-Function-Attributes.html#AArch64-Function-Attributes 7022 18. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/ARM-Function-Attributes.html#ARM-Function-Attributes 7023 19. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Named-Address-Spaces.html#Named-Address-Spaces 7024 20. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/S_002f390-Function-Attributes.html#S_002f390-Function-Attributes 7025 21. http://www.musl-libc.org/ 7026 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.2 7027 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.3 7028 24. https://www.intel.com/content/www/us/en/developer/articles/technical/deprecate-pcommit-instruction.html 7029 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.4 7030 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.5 7031 27. https://gcc.gnu.org/onlinedocs/ 7032 28. mailto:gcc-help (a] gcc.gnu.org 7033 29. mailto:gcc (a] gcc.gnu.org 7034 30. https://gcc.gnu.org/lists.html 7035 31. https://www.fsf.org/ 7036 32. https://gcc.gnu.org/about.html 7037 ====================================================================== 7038 http://gcc.gnu.org/gcc-5/index.html 7039 7040 GCC 5 Release Series 7041 7042 (This release series is no longer supported.) 7043 7044 October 10, 2017 7045 7046 The [1]GNU project and the GCC developers are pleased to announce the 7047 release of GCC 5.5. 7048 7049 This release is a bug-fix release, containing fixes for regressions in 7050 GCC 5.4 relative to previous releases of GCC. 7051 7052 Release History 7053 7054 GCC 5.5 7055 October 10, 2017 ([2]changes, [3]documentation) 7056 7057 GCC 5.4 7058 June 3, 2016 ([4]changes, [5]documentation) 7059 7060 GCC 5.3 7061 December 4, 2015 ([6]changes, [7]documentation) 7062 7063 GCC 5.2 7064 July 16, 2015 ([8]changes, [9]documentation) 7065 7066 GCC 5.1 7067 April 22, 2015 ([10]changes, [11]documentation) 7068 7069 References and Acknowledgements 7070 7071 GCC used to stand for the GNU C Compiler, but since the compiler 7072 supports several other languages aside from C, it now stands for the 7073 GNU Compiler Collection. 7074 7075 A list of [12]successful builds is updated as new information becomes 7076 available. 7077 7078 The GCC developers would like to thank the numerous people that have 7079 contributed new features, improvements, bug fixes, and other changes as 7080 well as test results to GCC. This [13]amazing group of volunteers is 7081 what makes GCC successful. 7082 7083 For additional information about GCC please refer to the [14]GCC 7084 project web site or contact the [15]GCC development mailing list. 7085 7086 To obtain GCC please use [16]our mirror sites or [17]our version 7087 control system. 7088 7089 7090 For questions related to the use of GCC, please consult these web 7091 pages and the [18]GCC manuals. If that fails, the 7092 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 7093 web pages and the development of GCC are welcome on our developer 7094 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 7095 archives. 7096 7097 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 7098 distribution of this entire article is permitted in any medium, 7099 provided this notice is preserved. 7100 7101 These pages are [23]maintained by the GCC team. Last modified 7102 2022-10-26. 7103 7104 References 7105 7106 1. http://www.gnu.org/ 7107 2. http://gcc.gnu.org/gcc-5/changes.html 7108 3. http://gcc.gnu.org/onlinedocs/5.5.0/ 7109 4. http://gcc.gnu.org/gcc-5/changes.html 7110 5. http://gcc.gnu.org/onlinedocs/5.4.0/ 7111 6. http://gcc.gnu.org/gcc-5/changes.html 7112 7. http://gcc.gnu.org/onlinedocs/5.3.0/ 7113 8. http://gcc.gnu.org/gcc-5/changes.html 7114 9. http://gcc.gnu.org/onlinedocs/5.2.0/ 7115 10. http://gcc.gnu.org/gcc-5/changes.html 7116 11. http://gcc.gnu.org/onlinedocs/5.1.0/ 7117 12. http://gcc.gnu.org/gcc-5/buildstat.html 7118 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 7119 14. http://gcc.gnu.org/index.html 7120 15. mailto:gcc (a] gcc.gnu.org 7121 16. http://gcc.gnu.org/mirrors.html 7122 17. http://gcc.gnu.org/git.html 7123 18. https://gcc.gnu.org/onlinedocs/ 7124 19. mailto:gcc-help (a] gcc.gnu.org 7125 20. mailto:gcc (a] gcc.gnu.org 7126 21. https://gcc.gnu.org/lists.html 7127 22. https://www.fsf.org/ 7128 23. https://gcc.gnu.org/about.html 7129 ====================================================================== 7130 http://gcc.gnu.org/gcc-5/changes.html 7131 7132 GCC 5 Release Series 7133 Changes, New Features, and Fixes 7134 7135 Caveats 7136 7137 * The default mode for C is now -std=gnu11 instead of -std=gnu89. 7138 * The C++ runtime library (libstdc++) uses a new ABI by default (see 7139 [1]below). 7140 * The Graphite framework for loop optimizations no longer requires 7141 the CLooG library, only ISL version 0.14 (recommended) or 0.12.2. 7142 The installation manual contains more information about 7143 requirements to build GCC. 7144 * The non-standard C++0x type traits has_trivial_default_constructor, 7145 has_trivial_copy_constructor and has_trivial_copy_assign have been 7146 deprecated and will be removed in a future version. The standard 7147 C++11 traits is_trivially_default_constructible, 7148 is_trivially_copy_constructible and is_trivially_copy_assignable 7149 should be used instead. 7150 * On AVR, support has been added for the devices 7151 ATtiny4/5/9/10/20/40. This requires Binutils 2.25 or newer. 7152 * The AVR port uses a new scheme to describe supported devices: For 7153 each supported device the compiler provides a device-specific 7154 [2]spec file. If the compiler is used together with AVR-LibC, this 7155 requires at least GCC 5.2 and a version of AVR-LibC which 7156 implements [3]feature #44574. 7157 7158 General Optimizer Improvements 7159 7160 * Inter-procedural optimization improvements: 7161 + An Identical Code Folding (ICF) pass (controlled via 7162 -fipa-icf) has been added. Compared to the identical code 7163 folding performed by the Gold linker this pass does not 7164 require function sections. It also performs merging before 7165 inlining, so inter-procedural optimizations are aware of the 7166 code re-use. On the other hand not all unifications performed 7167 by a linker are doable by GCC which must honor aliasing 7168 information. During link-time optimization of Firefox, this 7169 pass unifies about 31000 functions, that is 14% overall. 7170 + The devirtualization pass was significantly improved by adding 7171 better support for speculative devirtualization and dynamic 7172 type detection. About 50% of virtual calls in Firefox are now 7173 speculatively devirtualized during link-time optimization. 7174 + A new comdat localization pass allows the linker to eliminate 7175 more dead code in presence of C++ inline functions. 7176 + Virtual tables are now optimized. Local aliases are used to 7177 reduce dynamic linking time of C++ virtual tables on ELF 7178 targets and data alignment has been reduced to limit data 7179 segment bloat. 7180 + A new -fno-semantic-interposition option can be used to 7181 improve code quality of shared libraries where interposition 7182 of exported symbols is not allowed. 7183 + Write-only variables are now detected and optimized out. 7184 + With profile feedback the function inliner can now bypass 7185 --param inline-insns-auto and --param inline-insns-single 7186 limits for hot calls. 7187 + The IPA reference pass was significantly sped up making it 7188 feasible to enable -fipa-reference with -fprofile-generate. 7189 This also solves a bottleneck seen when building Chromium with 7190 link-time optimization. 7191 + The symbol table and call-graph API was reworked to C++ and 7192 simplified. 7193 + The interprocedural propagation of constants now also 7194 propagates alignments of pointer parameters. This for example 7195 means that the vectorizer often does not need to generate loop 7196 prologues and epilogues to make up for potential 7197 misalignments. 7198 * Link-time optimization improvements: 7199 + One Definition Rule based merging of C++ types has been 7200 implemented. Type merging enables better devirtualization and 7201 alias analysis. Streaming extra information needed to merge 7202 types adds about 2-6% of memory size and object size increase. 7203 This can be controlled by -flto-odr-type-merging. 7204 + Command-line optimization and target options are now streamed 7205 on a per-function basis and honored by the link-time 7206 optimizer. This change makes link-time optimization a more 7207 transparent replacement of per-file optimizations. It is now 7208 possible to build projects that require different optimization 7209 settings for different translation units (such as -ffast-math, 7210 -mavx, or -finline). Contrary to earlier GCC releases, the 7211 optimization and target options passed on the link command 7212 line are ignored. 7213 Note that this applies only to those command-line options that 7214 can be passed to optimize and target attributes. Command-line 7215 options affecting global code generation (such as -fpic), 7216 warnings (such as -Wodr), optimizations affecting the way 7217 static variables are optimized (such as -fcommon), debug 7218 output (such as -g), and --param parameters can be applied 7219 only to the whole link-time optimization unit. In these cases, 7220 it is recommended to consistently use the same options at both 7221 compile time and link time. 7222 + GCC bootstrap now uses slim LTO object files. 7223 + Memory usage and link times were improved. Tree merging was 7224 sped up, memory usage of GIMPLE declarations and types was 7225 reduced, and, support for on-demand streaming of variable 7226 constructors was added. 7227 * Feedback directed optimization improvements: 7228 + A new auto-FDO mode uses profiles collected by low overhead 7229 profiling tools (perf) instead of more expensive program 7230 instrumentation (via -fprofile-generate). SPEC2006 benchmarks 7231 on x86-64 improve by 4.7% with auto-FDO and by 7.3% with 7232 traditional feedback directed optimization. 7233 + Profile precision was improved in presence of C++ inline and 7234 extern inline functions. 7235 + The new gcov-tool utility allows manipulating profiles. 7236 + Profiles are now more tolerant to source file changes (this 7237 can be controlled by --param profile-func-internal-id). 7238 * Register allocation improvements: 7239 + A new local register allocator (LRA) sub-pass, controlled by 7240 -flra-remat, implements control-flow sensitive global register 7241 rematerialization. Instead of spilling and restoring a 7242 register value, it is recalculated if it is profitable. The 7243 sub-pass improved SPEC2000 generated code by 1% and 0.5% 7244 correspondingly on ARM and x86-64. 7245 + Reuse of the PIC hard register, instead of using a fixed 7246 register, was implemented on x86/x86-64 targets. This improves 7247 generated PIC code performance as more hard registers can be 7248 used. Shared libraries can significantly benefit from this 7249 optimization. Currently it is switched on only for x86/x86-64 7250 targets. As RA infrastructure is already implemented for PIC 7251 register reuse, other targets might follow this in the future. 7252 + A simple form of inter-procedural RA was implemented. When it 7253 is known that a called function does not use caller-saved 7254 registers, save/restore code is not generated around the call 7255 for such registers. This optimization can be controlled by 7256 -fipa-ra 7257 + LRA is now much more effective at generating spills of general 7258 registers into vector registers instead of memory on 7259 architectures (e.g., modern Intel processors) where this is 7260 profitable. 7261 * UndefinedBehaviorSanitizer gained a few new sanitization options: 7262 + -fsanitize=float-divide-by-zero: detect floating-point 7263 division by zero; 7264 + -fsanitize=float-cast-overflow: check that the result of 7265 floating-point type to integer conversions do not overflow; 7266 + -fsanitize=bounds: enable instrumentation of array bounds and 7267 detect out-of-bounds accesses; 7268 + -fsanitize=alignment: enable alignment checking, detect 7269 various misaligned objects; 7270 + -fsanitize=object-size: enable object size checking, detect 7271 various out-of-bounds accesses. 7272 + -fsanitize=vptr: enable checking of C++ member function calls, 7273 member accesses and some conversions between pointers to base 7274 and derived classes, detect if the referenced object does not 7275 have the correct dynamic type. 7276 * Pointer Bounds Checker, a bounds violation detector, has been added 7277 and can be enabled via -fcheck-pointer-bounds. Memory accesses are 7278 instrumented with run-time checks of used pointers against their 7279 bounds to detect pointer bounds violations (overflows). The Pointer 7280 Bounds Checker is available on x86/x86-64 GNU/Linux targets with a 7281 new ISA extension Intel MPX support. See the Pointer Bounds Checker 7282 [4]Wiki page for more details. 7283 7284 New Languages and Language specific improvements 7285 7286 * [5]OpenMP 4.0 specification offloading features are now supported 7287 by the C, C++, and Fortran compilers. Generic changes: 7288 + Infrastructure (suitable for any vendor). 7289 + Testsuite which covers offloading from the [6]OpenMP 4.0 7290 Examples document. 7291 Specific for upcoming Intel Xeon Phi products: 7292 + Run-time library. 7293 + Card emulator. 7294 * GCC 5 includes a preliminary implementation of the OpenACC 2.0a 7295 specification. OpenACC is intended for programming accelerator 7296 devices such as GPUs. See [7]the OpenACC wiki page for more 7297 information. 7298 7299 C family 7300 7301 * The default setting of the -fdiagnostics-color= command-line option 7302 is now [8]configurable when building GCC using configuration option 7303 --with-diagnostics-color=. The possible values are: never, always, 7304 auto and auto-if-env. The new default auto uses color only when the 7305 standard error is a terminal. The default in GCC 4.9 was 7306 auto-if-env, which is equivalent to auto if there is a non-empty 7307 GCC_COLORS environment variable, and never otherwise. As in GCC 7308 4.9, an empty GCC_COLORS variable in the environment will always 7309 disable colors, no matter what the default is or what command-line 7310 options are used. 7311 * A new command-line option -Wswitch-bool has been added for the C 7312 and C++ compilers, which warns whenever a switch statement has an 7313 index of boolean type. 7314 * A new command-line option -Wlogical-not-parentheses has been added 7315 for the C and C++ compilers, which warns about "logical not" used 7316 on the left hand side operand of a comparison. 7317 * A new command-line option -Wsizeof-array-argument has been added 7318 for the C and C++ compilers, which warns when the sizeof operator 7319 is applied to a parameter that has been declared as an array in a 7320 function definition. 7321 * A new command-line option -Wbool-compare has been added for the C 7322 and C++ compilers, which warns about boolean expressions compared 7323 with an integer value different from true/false. 7324 * Full support for Cilk Plus has been added to the GCC compiler. Cilk 7325 Plus is an extension to the C and C++ languages to support data and 7326 task parallelism. 7327 * A new attribute no_reorder prevents reordering of selected symbols 7328 against other such symbols or inline assembler. This enables to 7329 link-time optimize the Linux kernel without having to resort to 7330 -fno-toplevel-reorder that disables several optimizations. 7331 * New preprocessor constructs, __has_include and __has_include_next, 7332 to test the availability of headers have been added. 7333 This demonstrates a way to include the header <optional> only if it 7334 is available: 7335 7336 #ifdef __has_include 7337 # if __has_include(<optional>) 7338 # include <optional> 7339 # define have_optional 1 7340 # elif __has_include(<experimental/optional>) 7341 # include <experimental/optional> 7342 # define have_optional 1 7343 # define experimental_optional 7344 # else 7345 # define have_optional 0 7346 # endif 7347 #endif 7348 7349 The header search paths for __has_include and __has_include_next 7350 are equivalent to those of the standard directive #include and the 7351 extension #include_next respectively. 7352 * A new built-in function-like macro to determine the existence of an 7353 attribute, __has_attribute, has been added. The equivalent built-in 7354 macro __has_cpp_attribute was added to C++ to support 7355 [9]Feature-testing recommendations for C++. The macro 7356 __has_attribute is added to all C-like languages as an extension: 7357 7358 int 7359 #ifdef __has_attribute 7360 # if __has_attribute(__noinline__) 7361 __attribute__((__noinline__)) 7362 # endif 7363 #endif 7364 foo(int x); 7365 7366 If an attribute exists, a nonzero constant integer is returned. For 7367 standardized C++ attributes a date is returned, otherwise the 7368 constant returned is 1. Both __has_attribute and 7369 __has_cpp_attribute will add underscores to an attribute name if 7370 necessary to resolve the name. For C++11 and onwards the attribute 7371 may be scoped. 7372 * A new set of built-in functions for arithmetics with overflow 7373 checking has been added: __builtin_add_overflow, 7374 __builtin_sub_overflow and __builtin_mul_overflow and for 7375 compatibility with clang also other variants. These builtins have 7376 two integral arguments (which don't need to have the same type), 7377 the arguments are extended to infinite precision signed type, +, - 7378 or * is performed on those, and the result is stored in an integer 7379 variable pointed to by the last argument. If the stored value is 7380 equal to the infinite precision result, the built-in functions 7381 return false, otherwise true. The type of the integer variable that 7382 will hold the result can be different from the types of the first 7383 two arguments. The following snippet demonstrates how this can be 7384 used in computing the size for the calloc function: 7385 7386 void * 7387 calloc (size_t x, size_t y) 7388 { 7389 size_t sz; 7390 if (__builtin_mul_overflow (x, y, &sz)) 7391 return NULL; 7392 void *ret = malloc (sz); 7393 if (ret) memset (res, 0, sz); 7394 return ret; 7395 } 7396 7397 On e.g. i?86 or x86-64 the above will result in a mul instruction 7398 followed by a jump on overflow. 7399 * The option -fextended-identifiers is now enabled by default for 7400 C++, and for C99 and later C versions. Various bugs in the 7401 implementation of extended identifiers have been fixed. 7402 7403 C 7404 7405 * The default mode has been changed to -std=gnu11. 7406 * A new command-line option -Wc90-c99-compat has been added to warn 7407 about features not present in ISO C90, but present in ISO C99. 7408 * A new command-line option -Wc99-c11-compat has been added to warn 7409 about features not present in ISO C99, but present in ISO C11. 7410 * It is possible to disable warnings about conversions between 7411 pointers that have incompatible types via a new warning option 7412 -Wno-incompatible-pointer-types; warnings about implicit 7413 incompatible integer to pointer and pointer to integer conversions 7414 via a new warning option -Wno-int-conversion; and warnings about 7415 qualifiers on pointers being discarded via a new warning option 7416 -Wno-discarded-qualifiers. 7417 * To allow proper use of const qualifiers with multidimensional 7418 arrays, GCC will not warn about incompatible pointer types anymore 7419 for conversions between pointers to arrays with and without const 7420 qualifier (except when using -pedantic). Instead, a new warning is 7421 emitted only if the const qualifier is lost. This can be controlled 7422 with a new warning option -Wno-discarded-array-qualifiers. 7423 * The C front end now generates more precise caret diagnostics. 7424 * The -pg command-line option now only affects the current file in an 7425 LTO build. 7426 7427 C++ 7428 7429 * G++ now supports [10]C++14 variable templates. 7430 * -Wnon-virtual-dtor doesn't warn anymore for final classes. 7431 * Excessive template instantiation depth is now a fatal error. This 7432 prevents excessive diagnostics that usually do not help to identify 7433 the problem. 7434 * G++ and libstdc++ now implement the feature-testing macros from 7435 [11]Feature-testing recommendations for C++. 7436 * G++ now allows typename in a template template parameter. 7437 7438 template<template<typename> typename X> struct D; // OK 7439 7440 * G++ now supports [12]C++14 aggregates with non-static data member 7441 initializers. 7442 7443 struct A { int i, j = i; }; 7444 A a = { 42 }; // a.j is also 42 7445 7446 * G++ now supports [13]C++14 extended constexpr. 7447 7448 constexpr int f (int i) 7449 { 7450 int j = 0; 7451 for (; i > 0; --i) 7452 ++j; 7453 return j; 7454 } 7455 7456 constexpr int i = f(42); // i is 42 7457 7458 * G++ now supports the [14]C++14 sized deallocation functions. 7459 7460 void operator delete (void *, std::size_t) noexcept; 7461 void operator delete[] (void *, std::size_t) noexcept; 7462 7463 * A new One Definition Rule violation warning (controlled by -Wodr) 7464 detects mismatches in type definitions and virtual table contents 7465 during link-time optimization. 7466 * New warnings -Wsuggest-final-types and -Wsuggest-final-methods help 7467 developers to annotate programs with final specifiers (or anonymous 7468 namespaces) to improve code generation. These warnings can be used 7469 at compile time, but they are more useful in combination with 7470 link-time optimization. 7471 * G++ no longer supports [15]N3639 variable length arrays, as they 7472 were removed from the C++14 working paper prior to ratification. 7473 GNU VLAs are still supported, so VLA support is now the same in 7474 C++14 mode as in C++98 and C++11 modes. 7475 * G++ now allows passing a non-trivially-copyable class via C 7476 varargs, which is conditionally-supported with 7477 implementation-defined semantics in the standard. This uses the 7478 same calling convention as a normal value parameter. 7479 * G++ now defaults to -fabi-version=9 and -fabi-compat-version=2. So 7480 various mangling bugs are fixed, but G++ will still emit aliases 7481 with the old, wrong mangling where feasible. -Wabi=2 will warn 7482 about differences between ABI version 2 and the current setting. 7483 * G++ 5.2 fixes the alignment of std::nullptr_t. Most code is likely 7484 to be unaffected, but -Wabi=8 will warn about a non-static data 7485 member with type std::nullptr_t which changes position due to this 7486 change. 7487 7488 Runtime Library (libstdc++) 7489 7490 * A [16]Dual ABI is provided by the library. A new ABI is enabled by 7491 default. The old ABI is still supported and can be used by defining 7492 the macro _GLIBCXX_USE_CXX11_ABI to 0 before including any C++ 7493 standard library headers. 7494 * A new implementation of std::string is enabled by default, using 7495 the small string optimization instead of copy-on-write reference 7496 counting. 7497 * A new implementation of std::list is enabled by default, with an 7498 O(1) size() function; 7499 * [17]Full support for C++11, including the following new features: 7500 + std::deque and std::vector<bool> meet the allocator-aware 7501 container requirements; 7502 + movable and swappable iostream classes; 7503 + support for std::align and std::aligned_union; 7504 + type traits std::is_trivially_copyable, 7505 std::is_trivially_constructible, std::is_trivially_assignable 7506 etc.; 7507 + I/O manipulators std::put_time, std::get_time, std::hexfloat 7508 and std::defaultfloat; 7509 + generic locale-aware std::isblank; 7510 + locale facets for Unicode conversion; 7511 + atomic operations for std::shared_ptr; 7512 + std::notify_all_at_thread_exit() and functions for making 7513 futures ready at thread exit. 7514 * Support for the C++11 hexfloat manipulator changes how the num_put 7515 facet formats floating point types when 7516 ios_base::fixed|ios_base::scientific is set in a stream's fmtflags. 7517 This change affects all language modes, even though the C++98 7518 standard gave no special meaning to that combination of flags. To 7519 prevent the use of hexadecimal notation for floating point types 7520 use str.unsetf(std::ios_base::floatfield) to clear the relevant 7521 bits in str.flags(). 7522 * [18]Full experimental support for C++14, including the following 7523 new features: 7524 + std::is_final type trait; 7525 + heterogeneous comparison lookup in associative containers. 7526 + global functions cbegin, cend, rbegin, rend, crbegin, and 7527 crend for range access to containers, arrays and initializer 7528 lists. 7529 * [19]Improved experimental support for the Library Fundamentals TS, 7530 including: 7531 + class std::experimental::any; 7532 + function template std::experimental::apply; 7533 + function template std::experimental::sample; 7534 + function template std::experimental::search and related 7535 searcher types; 7536 + variable templates for type traits; 7537 + function template std::experimental::not_fn. 7538 * New random number distributions logistic_distribution and 7539 uniform_on_sphere_distribution as extensions. 7540 * [20]GDB Xmethods for containers and std::unique_ptr. 7541 7542 Fortran 7543 7544 * Compatibility notice: 7545 + The version of the module files (.mod) has been incremented. 7546 + For free-form source files [21]-Werror=line-truncation is now 7547 enabled by default. Note that comments exceeding the line 7548 length are not diagnosed. (For fixed-form source code, the 7549 same warning is available but turned off by default, such that 7550 excess characters are ignored. -ffree-line-length-n and 7551 -ffixed-line-length-n can be used to modify the default line 7552 lengths of 132 and 72 columns, respectively.) 7553 + The -Wtabs option is now more sensible: with -Wtabs the 7554 compiler warns if it encounters tabs and with -Wno-tabs this 7555 warning is turned off. Before, -Wno-tabs warned and -Wtabs 7556 disabled the warning. As before, this warning is also enabled 7557 by -Wall, -pedantic and the f95, f2003, f2008 and f2008ts 7558 options of -std=. 7559 * Incomplete support for colorizing diagnostics emitted by gfortran 7560 has been added. The option [22]-fdiagnostics-color controls when 7561 color is used in diagnostics. The default value of this option can 7562 be [23]configured when building GCC. The GCC_COLORS environment 7563 variable can be used to customize the colors or disable coloring 7564 completely. Sample diagnostics output: 7565 $ gfortran -fdiagnostics-color=always -Wuse-without-only test.f90 7566 test.f90:6:1: 7567 7568 0 continue 7569 1 7570 Error: Zero is not a valid statement label at (1) 7571 test.f90:9:6: 7572 7573 USE foo 7574 1 7575 Warning: USE statement at (1) has no ONLY qualifier [-Wuse-without-only] 7576 7577 * The -Wuse-without-only option has been added to warn when a USE 7578 statement has no ONLY qualifier and thus implicitly imports all 7579 public entities of the used module. 7580 * Formatted READ and WRITE statements now work correctly in 7581 locale-aware programs. For more information and potential caveats, 7582 see [24]Section 5.3 Thread-safety of the runtime library in the 7583 manual. 7584 * [25]Fortran 2003: 7585 + The intrinsic IEEE modules (IEEE_FEATURES, IEEE_EXCEPTIONS and 7586 IEEE_ARITHMETIC) are now supported. 7587 * [26]Fortran 2008: 7588 + [27]Coarrays: Full experimental support of Fortran 2008's 7589 coarrays with -fcoarray=lib except for allocatable/pointer 7590 components of derived-type coarrays. GCC currently only ships 7591 with a single-image library (libcaf_single), but multi-image 7592 support based on MPI and GASNet is provided by the libraries 7593 of the [28]OpenCoarrays project. 7594 * TS18508 Additional Parallel Features in Fortran: 7595 + Support for the collective intrinsic subroutines CO_MAX, 7596 CO_MIN, CO_SUM, CO_BROADCAST and CO_REDUCE has been added, 7597 including -fcoarray=lib support. 7598 + Support for the new atomic intrinsics has been added, 7599 including -fcoarray=lib support. 7600 * Fortran 2015: 7601 + Support for IMPLICIT NONE (external, type). 7602 + ERROR STOP is now permitted in pure procedures. 7603 7604 Go 7605 7606 * GCC 5 provides a complete implementation of the Go 1.4.2 release. 7607 * Building GCC 5 with Go enabled will install two new programs: 7608 [29]go and [30]gofmt. 7609 7610 libgccjit 7611 7612 New in GCC 5 is the ability to build GCC as a shared library for 7613 embedding in other processes (such as interpreters), suitable for 7614 Just-In-Time compilation to machine code. 7615 7616 The shared library has a [31]C API and a [32]C++ wrapper API providing 7617 some "syntactic sugar". There are also bindings available from 3rd 7618 parties for [33]Python and for [34]D. 7619 7620 For example, this library can be used by interpreters for [35]compiling 7621 functions from bytecode to machine code. 7622 7623 The library can also be used for ahead-of-time compilation, enabling 7624 GCC to be plugged into a pre-existing front end. An example of using 7625 this to build a compiler for an esoteric language we'll refer to as 7626 "brainf" can be seen [36]here. 7627 7628 libgccjit is licensed under the GPLv3 (or at your option, any later 7629 version) 7630 7631 It should be regarded as experimental at this time. 7632 7633 New Targets and Target Specific Improvements 7634 7635 Reporting stack usage 7636 7637 * The BFIN, FT32, H8300, IQ2000 and M32C targets now support the 7638 -fstack-usage option. 7639 7640 AArch64 7641 7642 * Code generation for the ARM Cortex-A57 processor has been improved. 7643 A more accurate instruction scheduling model for the processor is 7644 now used, and a number of compiler tuning parameters have been set 7645 to offer increased performance when compiling with -mcpu=cortex-a57 7646 or -mtune=cortex-a57. 7647 * A workaround for the ARM Cortex-A53 erratum 835769 has been added 7648 and can be enabled by giving the -mfix-cortex-a53-835769 option. 7649 Alternatively it can be enabled by default by configuring GCC with 7650 the --enable-fix-cortex-a53-835769 option. 7651 * The optional cryptographic extensions to the ARMv8-A architecture 7652 are no longer enabled by default when specifying the 7653 -mcpu=cortex-a53, -mcpu=cortex-a57 or -mcpu=cortex-a57.cortex-a53 7654 options. To enable these extensions add +crypto to the value of 7655 -mcpu or -march e.g. -mcpu=cortex-a53+crypto. 7656 * Support has been added for the following processors (GCC 7657 identifiers in parentheses): ARM Cortex-A72 (cortex-a72) and 7658 initial support for its big.LITTLE combination with the ARM 7659 Cortex-A53 (cortex-a72.cortex-a53), Cavium ThunderX (thunderx), 7660 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 7661 The GCC identifiers can be used as arguments to the -mcpu or -mtune 7662 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 7663 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 7664 support for the Cortex-A72. 7665 * The transitional options -mlra and -mno-lra have been removed. The 7666 AArch64 backend now uses the local register allocator (LRA) only. 7667 7668 ARM 7669 7670 * Thumb-1 assembly code is now generated in unified syntax. The new 7671 option -masm-syntax-unified specifies whether inline assembly code 7672 is using unified syntax. By default the option is off which means 7673 non-unified syntax is used. However this is subject to change in 7674 future releases. Eventually the non-unified syntax will be 7675 deprecated. 7676 * It is now a configure-time error to use the --with-cpu configure 7677 option with either of --with-tune or --with-arch. 7678 * Code generation for the ARM Cortex-A57 processor has been improved. 7679 A more accurate instruction scheduling model for the processor is 7680 now used, and a number of compiler tuning parameters have been set 7681 to offer increased performance when compiling with -mcpu=cortex-a57 7682 or -mtune=cortex-a57. 7683 * Support has been added for the following processors (GCC 7684 identifiers in parentheses): ARM Cortex-A17 (cortex-a17) and 7685 initial support for its big.LITTLE combination with the ARM 7686 Cortex-A7 (cortex-a17.cortex-a7), ARM Cortex-A72 (cortex-a72) and 7687 initial support for its big.LITTLE combination with the ARM 7688 Cortex-A53 (cortex-a72.cortex-a53), ARM Cortex-M7 (cortex-m7), 7689 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 7690 The GCC identifiers can be used as arguments to the -mcpu or -mtune 7691 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 7692 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 7693 support for the Cortex-A72. 7694 * The deprecated option -mwords-little-endian has been removed. 7695 * The options -mapcs, -mapcs-frame, -mtpcs-frame and 7696 -mtpcs-leaf-frame which are only applicable to the old ABI have 7697 been deprecated. 7698 * The transitional options -mlra and -mno-lra have been removed. The 7699 ARM backend now uses the local register allocator (LRA) only. 7700 7701 AVR 7702 7703 * The compiler no more supports individual devices like ATmega8. 7704 Specifying, say, -mmcu=atmega8 triggers the usage of the 7705 device-specific [37]spec file specs-atmega8 which is part of the 7706 installation and describes options for the sub-processes like 7707 compiler proper, assembler and linker. You can add support for a 7708 new device -mmcu=mydevice as follows: 7709 1. In an empty directory /someplace, create a new directory 7710 device-specs. 7711 2. Copy a device spec file from the installed device-specs 7712 folder, follow the comments in that file and then save it as 7713 /someplace/device-specs/specs-mydevice. 7714 3. Add -B /someplace -mmcu=mydevice to the compiler's 7715 command-line options. Notice that /someplace must specify an 7716 absolute path and that mydevice must not start with "avr". 7717 4. Provided you have a device-specific library libmydevice.a 7718 available, you can put it at /someplace, dito for a 7719 device-specific startup file crtmydevice.o. 7720 The contents of the device spec files depend on the compiler's 7721 configuration, in particular on --with-avrlibc=no and whether or 7722 not it is configured for RTEMS. 7723 * A new command-line option -nodevicelib has been added. It prevents 7724 the compiler from linking against AVR-LibC's device-specific 7725 library libdevice.a. 7726 * The following three command-line options have been added: 7727 7728 -mrmw 7729 Set if the device supports the read-modify-write 7730 instructions LAC, LAS, LAT and XCH. 7731 7732 -mn-flash=size 7733 Specify the flash size of the device in units of 64 KiB, 7734 rounded up to the next integer as needed. This option 7735 affects the availability of the [38]AVR address-spaces. 7736 7737 -mskip-bug 7738 Set if the device is affected by the respective silicon 7739 bug. 7740 7741 In general, you don't need to set these options by hand. The new 7742 device-specific spec file will set them as needed. 7743 7744 IA-32/x86-64 7745 7746 * New ISA extensions support AVX-512{BW,DQ,VL,IFMA,VBMI} of Intel's 7747 CPU codenamed Skylake Server was added to GCC. That includes inline 7748 assembly support, new intrinsics, and basic autovectorization. 7749 These new AVX-512 extensions are available via the following GCC 7750 switches: AVX-512 Vector Length EVEX feature: -mavx512vl, AVX-512 7751 Byte and Word instructions: -mavx512bw, AVX-512 Dword and Qword 7752 instructions: -mavx512dq, AVX-512 FMA-52 instructions: -mavx512ifma 7753 and for AVX-512 Vector Bit Manipulation Instructions: -mavx512vbmi. 7754 * New ISA extensions support Intel MPX was added to GCC. This new 7755 extension is available via the -mmpx compiler switch. Intel MPX is 7756 a set of processor features which, with compiler, run-time library 7757 and OS support, brings increased robustness to software by run-time 7758 checking pointer references against their bounds. In GCC Intel MPX 7759 is supported by Pointer Bounds Checker and libmpx run-time 7760 libraries. 7761 * The new -mrecord-mcount option for -pg generates a Linux kernel 7762 style table of pointers to mcount or __fentry__ calls at the 7763 beginning of functions. The new -mnop-mcount option in addition 7764 also generates nops in place of the __fentry__ or mcount call, so 7765 that a call per function can be later patched in. This can be used 7766 for low overhead tracing or hot code patching. 7767 * The new -malign-data option controls how GCC aligns variables. 7768 -malign-data=compat uses increased alignment compatible with GCC 7769 4.8 and earlier, -malign-data=abi uses alignment as specified by 7770 the psABI, and -malign-data=cacheline uses increased alignment to 7771 match the cache line size. -malign-data=compat is the default. 7772 * The new -mskip-rax-setup option skips setting up the RAX register 7773 when SSE is disabled and there are no variable arguments passed in 7774 vector registers. This can be used to optimize the Linux kernel. 7775 7776 MIPS 7777 7778 * MIPS Releases 3 and 5 are now directly supported. Use the 7779 command-line options -mips32r3, -mips64r3, -mips32r5 and -mips64r5 7780 to enable code-generation for these processors. 7781 * The Imagination P5600 processor is now supported using the 7782 -march=p5600 command-line option. 7783 * The Cavium Octeon3 processor is now supported using the 7784 -march=octeon3 command-line option. 7785 * MIPS Release 6 is now supported using the -mips32r6 and -mips64r6 7786 command-line options. 7787 * The o32 ABI has been modified and extended. The o32 64-bit 7788 floating-point register support is now obsolete and has been 7789 removed. It has been replaced by three ABI extensions FPXX, FP64A, 7790 and FP64. The meaning of the -mfp64 command-line option has 7791 changed. It is now used to enable the FP64A and FP64 ABI 7792 extensions. 7793 + The FPXX extension requires that code generated to access 7794 double-precision values use even-numbered registers. Code that 7795 adheres to this extension is link-compatible with all other 7796 o32 double-precision ABI variants and will execute correctly 7797 in all hardware FPU modes. The command-line options -mabi=32 7798 -mfpxx can be used to enable this extension. MIPS II is the 7799 minimum processor required. 7800 + The o32 FP64A extension requires that floating-point registers 7801 be 64-bit and odd-numbered single-precision registers are not 7802 allowed. Code that adheres to the o32 FP64A variant is 7803 link-compatible with all other o32 double-precision ABI 7804 variants. The command-line options -mabi=32 -mfp64 7805 -mno-odd-spreg can be used to enable this extension. MIPS32R2 7806 is the minimum processor required. 7807 + The o32 FP64 extension also requires that floating-point 7808 registers be 64-bit, but permits the use of single-precision 7809 registers. Code that adheres to the o32 FP64 variant is 7810 link-compatible with o32 FPXX and o32 FP64A variants only, 7811 i.e. it is not compatible with the original o32 7812 double-precision ABI. The command-line options -mabi=32 -mfp64 7813 -modd-spreg can be used to enable this extension. MIPS32R2 is 7814 the minimum processor required. 7815 The new ABI variants can be enabled by default using the configure 7816 time options --with-fp-32=[32|xx|64] and --with(out)-odd-sp-reg-32. 7817 It is strongly recommended that all vendors begin to set o32 FPXX 7818 as the default ABI. This will be required to run the generated code 7819 on MIPSR5 cores in conjunction with future MIPS SIMD (MSA) code and 7820 MIPSR6 cores. 7821 * GCC will now pass all floating-point options to the assembler if 7822 GNU binutils 2.25 is used. As a result, any inline assembly code 7823 that uses hard-float instructions should be amended to include a 7824 .set directive to override the global assembler options when 7825 compiling for soft-float targets. 7826 7827 NDS32 7828 7829 * The variadic function ABI implementation is now compatible with 7830 past Andes toolchains where the caller uses registers to pass 7831 arguments and the callee is in charge of pushing them on stack. 7832 * The options -mforce-fp-as-gp, -mforbid-fp-as-gp, and -mex9 have 7833 been removed since they are not yet available in the nds32 port of 7834 GNU binutils. 7835 * A new option -mcmodel=[small|medium|large] supports varied code 7836 models on code generation. The -mgp-direct option became 7837 meaningless and can be discarded. 7838 7839 RX 7840 7841 * A new command line option -mno-allow-string-insns can be used to 7842 disable the generation of the SCMPU, SMOVU, SMOVB, SMOVF, SUNTIL, 7843 SWHILE and RMPA instructions. An erratum released by Renesas shows 7844 that it is unsafe to use these instructions on addresses within the 7845 I/O space of the processor. The new option can be used when the 7846 programmer is concerned that the I/O space might be accessed. The 7847 default is still to enable these instructions. 7848 7849 SH 7850 7851 * The compiler will now pass the appropriate --isa= option to the 7852 assembler. 7853 * The default handling for the GBR has been changed from call 7854 clobbered to call preserved. The old behavior can be reinstated by 7855 specifying the option -fcall-used-gbr. 7856 * Support for the SH4A fpchg instruction has been added which will be 7857 utilized when switching between single and double precision FPU 7858 modes. 7859 * The compiler no longer uses the __fpscr_values array for switching 7860 between single and double FPU precision modes on non-SH4A targets. 7861 Instead mode switching will now be performed by storing, modifying 7862 and reloading the FPSCR, so that other FPSCR bits are preserved 7863 across mode switches. The __fpscr_values array that is defined in 7864 libgcc is still present for backwards compatibility, but it will 7865 not be referenced by compiler generated code anymore. 7866 * New builtin functions __builtin_sh_get_fpscr and 7867 __builtin_sh_set_fpscr have been added. The __builtin_sh_set_fpscr 7868 function will mask the specified bits in such a way that the SZ, PR 7869 and FR mode bits will be preserved, while changing the other bits. 7870 These new functions do not reference the __fpscr_values array. The 7871 old functions __set_fpscr and __get_fpscr in libgcc which access 7872 the __fpscr_values array are still present for backwards 7873 compatibility, but their usage is highly discouraged. 7874 * Some improvements to code generated for __atomic built-in 7875 functions. 7876 * When compiling for SH2E the compiler will no longer force the usage 7877 of delay slots for conditional branch instructions bt and bf. The 7878 old behavior can be reinstated (e.g. to work around a hardware bug 7879 in the original SH7055) by specifying the new option 7880 -mcbranch-force-delay-slot. 7881 7882 Operating Systems 7883 7884 AIX 7885 7886 * GCC now supports stabs debugging continuation lines to allow long 7887 stabs debug information without overflow that generates AIX linker 7888 errors. 7889 7890 DragonFly BSD 7891 7892 * GCC now supports the DragonFly BSD operating system. 7893 7894 FreeBSD 7895 7896 * GCC now supports the FreeBSD operating system for the arm port 7897 through the arm*-*-freebsd* target triplets. 7898 7899 VxWorks MILS 7900 7901 * GCC now supports the MILS (Multiple Independent Levels of Security) 7902 variant of WindRiver's VxWorks operating system for PowerPC 7903 targets. 7904 7905 Other significant improvements 7906 7907 * The gcc-ar, gcc-nm, gcc-ranlib wrappers now understand a -B option 7908 to set the compiler to use. 7909 7910 * When the new command-line option -freport-bug is used, GCC 7911 automatically generates a developer-friendly reproducer whenever an 7912 internal compiler error is encountered. 7913 7914 GCC 5.2 7915 7916 This is the [39]list of problem reports (PRs) from GCC's bug tracking 7917 system that are known to be fixed in the 5.2 release. This list might 7918 not be complete (that is, it is possible that some PRs that have been 7919 fixed are not listed here). 7920 7921 Target Specific Changes 7922 7923 IA-32/x86-64 7924 7925 * Support for new AMD instructions monitorx and mwaitx has been 7926 added. This includes new intrinsic and built-in support. It is 7927 enabled through option -mmwaitx. The instructions monitorx and 7928 mwaitx implement the same functionality as the old monitor and 7929 mwait instructions. In addition, mwaitx adds a configurable timer. 7930 The timer value is received as third argument and stored in 7931 register %ebx. 7932 7933 S/390, System z, IBM z Systems 7934 7935 * Support for the IBM z13 processor has been added. When using the 7936 -march=z13 option, the compiler will generate code making use of 7937 the new instructions and registers introduced with the vector 7938 extension facility. The -mtune=z13 option enables z13 specific 7939 instruction scheduling without making use of new instructions. 7940 Compiling code with -march=z13 reduces the default alignment of 7941 vector types bigger than 8 bytes to 8. This is an ABI change and 7942 care must be taken when linking modules compiled with different 7943 arch levels which interchange variables containing vector type 7944 values. For newly compiled code the GNU linker will emit a warning. 7945 * The -mzvector option enables a C/C++ language extension. This 7946 extension provides a new keyword vector which can be used to define 7947 vector type variables. (Note: This is not available when enforcing 7948 strict standard compliance e.g. with -std=c99. Either enable GNU 7949 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 7950 Additionally a set of overloaded builtins is provided which is 7951 partially compatible to the PowerPC Altivec builtins. In order to 7952 make use of these builtins the vecintrin.h header file needs to be 7953 included. 7954 7955 GCC 5.3 7956 7957 This is the [40]list of problem reports (PRs) from GCC's bug tracking 7958 system that are known to be fixed in the 5.3 release. This list might 7959 not be complete (that is, it is possible that some PRs that have been 7960 fixed are not listed here). 7961 7962 Target Specific Changes 7963 7964 IA-32/x86-64 7965 7966 * GCC now supports the Intel CPU named Skylake with AVX-512 7967 extensions through -march=skylake-avx512. The switch enables the 7968 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 7969 AVX-512DQ. 7970 7971 S/390, System z, IBM z Systems 7972 7973 * With this version of GCC IBM z Systems support has been added to 7974 the GO runtime environment. GCC 5.3 has proven to be able to 7975 compile larger GO applications on IBM z Systems. 7976 7977 GCC 5.4 7978 7979 This is the [41]list of problem reports (PRs) from GCC's bug tracking 7980 system that are known to be fixed in the 5.4 release. This list might 7981 not be complete (that is, it is possible that some PRs that have been 7982 fixed are not listed here). 7983 7984 GCC 5.5 7985 7986 This is the [42]list of problem reports (PRs) from GCC's bug tracking 7987 system that are known to be fixed in the 5.5 release. This list might 7988 not be complete (that is, it is possible that some PRs that have been 7989 fixed are not listed here). 7990 7991 Target Specific Changes 7992 7993 IA-32/x86-64 7994 7995 * Support for the [43]deprecated pcommit instruction has been 7996 removed. 7997 7998 7999 For questions related to the use of GCC, please consult these web 8000 pages and the [44]GCC manuals. If that fails, the 8001 [45]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8002 web pages and the development of GCC are welcome on our developer 8003 list at [46]gcc (a] gcc.gnu.org. All of [47]our lists have public 8004 archives. 8005 8006 Copyright (C) [48]Free Software Foundation, Inc. Verbatim copying and 8007 distribution of this entire article is permitted in any medium, 8008 provided this notice is preserved. 8009 8010 These pages are [49]maintained by the GCC team. Last modified 8011 2023-02-20. 8012 8013 References 8014 8015 1. http://gcc.gnu.org/gcc-5/changes.html#libstdcxx 8016 2. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 8017 3. https://savannah.nongnu.org/bugs/?44574 8018 4. https://gcc.gnu.org/wiki/Intel%20MPX%20support%20in%20the%20GCC%20compiler 8019 5. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.pdf 8020 6. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.Examples.pdf 8021 7. https://gcc.gnu.org/wiki/OpenACC 8022 8. https://gcc.gnu.org/install/configure.html 8023 9. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 8024 10. http://gcc.gnu.org/projects/cxx1y.html 8025 11. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 8026 12. http://gcc.gnu.org/projects/cxx1y.html 8027 13. http://gcc.gnu.org/projects/cxx1y.html 8028 14. http://gcc.gnu.org/projects/cxx1y.html 8029 15. https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3639.html 8030 16. http://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html 8031 17. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2011 8032 18. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 8033 19. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 8034 20. https://sourceware.org/gdb/current/onlinedocs/gdb#Xmethods-In-Python 8035 21. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Error-and-Warning-Options.html 8036 22. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Language-Independent-Options.html 8037 23. https://gcc.gnu.org/install/configure.html 8038 24. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Thread-safety-of-the-runtime-library.html 8039 25. https://gcc.gnu.org/wiki/Fortran2003Status 8040 26. https://gcc.gnu.org/wiki/Fortran2008Status 8041 27. https://gcc.gnu.org/wiki/Coarray 8042 28. http://www.opencoarrays.org/ 8043 29. https://pkg.go.dev/cmd/go 8044 30. https://pkg.go.dev/cmd/gofmt 8045 31. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/index.html 8046 32. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/cp/index.html 8047 33. https://github.com/davidmalcolm/pygccjit 8048 34. https://github.com/ibuclaw/gccjitd 8049 35. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial04.html 8050 36. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial05.html 8051 37. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 8052 38. https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html 8053 39. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.2 8054 40. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.3 8055 41. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.4 8056 42. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.5 8057 43. https://www.intel.com/content/www/us/en/developer/articles/technical/deprecate-pcommit-instruction.html 8058 44. https://gcc.gnu.org/onlinedocs/ 8059 45. mailto:gcc-help (a] gcc.gnu.org 8060 46. mailto:gcc (a] gcc.gnu.org 8061 47. https://gcc.gnu.org/lists.html 8062 48. https://www.fsf.org/ 8063 49. https://gcc.gnu.org/about.html 8064 ====================================================================== 8065 http://gcc.gnu.org/gcc-4.9/index.html 8066 8067 GCC 4.9 Release Series 8068 8069 (This release series is no longer supported.) 8070 8071 Aug 3, 2016 8072 8073 The [1]GNU project and the GCC developers are pleased to announce the 8074 release of GCC 4.9.4. 8075 8076 This release is a bug-fix release, containing fixes for regressions in 8077 GCC 4.9.3 relative to previous releases of GCC. 8078 8079 Release History 8080 8081 GCC 4.9.4 8082 Aug 3, 2016 ([2]changes, [3]documentation) 8083 8084 GCC 4.9.3 8085 June 26, 2015 ([4]changes, [5]documentation) 8086 8087 GCC 4.9.2 8088 October 30, 2014 ([6]changes, [7]documentation) 8089 8090 GCC 4.9.1 8091 July 16, 2014 ([8]changes, [9]documentation) 8092 8093 GCC 4.9.0 8094 April 22, 2014 ([10]changes, [11]documentation) 8095 8096 References and Acknowledgements 8097 8098 GCC used to stand for the GNU C Compiler, but since the compiler 8099 supports several other languages aside from C, it now stands for the 8100 GNU Compiler Collection. 8101 8102 A list of [12]successful builds is updated as new information becomes 8103 available. 8104 8105 The GCC developers would like to thank the numerous people that have 8106 contributed new features, improvements, bug fixes, and other changes as 8107 well as test results to GCC. This [13]amazing group of volunteers is 8108 what makes GCC successful. 8109 8110 For additional information about GCC please refer to the [14]GCC 8111 project web site or contact the [15]GCC development mailing list. 8112 8113 To obtain GCC please use [16]our mirror sites or [17]our version 8114 control system. 8115 8116 8117 For questions related to the use of GCC, please consult these web 8118 pages and the [18]GCC manuals. If that fails, the 8119 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8120 web pages and the development of GCC are welcome on our developer 8121 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 8122 archives. 8123 8124 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 8125 distribution of this entire article is permitted in any medium, 8126 provided this notice is preserved. 8127 8128 These pages are [23]maintained by the GCC team. Last modified 8129 2022-10-26. 8130 8131 References 8132 8133 1. http://www.gnu.org/ 8134 2. http://gcc.gnu.org/gcc-4.9/changes.html 8135 3. http://gcc.gnu.org/onlinedocs/4.9.4/ 8136 4. http://gcc.gnu.org/gcc-4.9/changes.html 8137 5. http://gcc.gnu.org/onlinedocs/4.9.3/ 8138 6. http://gcc.gnu.org/gcc-4.9/changes.html 8139 7. http://gcc.gnu.org/onlinedocs/4.9.2/ 8140 8. http://gcc.gnu.org/gcc-4.9/changes.html 8141 9. http://gcc.gnu.org/onlinedocs/4.9.1/ 8142 10. http://gcc.gnu.org/gcc-4.9/changes.html 8143 11. https://gcc.gnu.org/onlinedocs/4.9.0/ 8144 12. http://gcc.gnu.org/gcc-4.9/buildstat.html 8145 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 8146 14. http://gcc.gnu.org/index.html 8147 15. mailto:gcc (a] gcc.gnu.org 8148 16. http://gcc.gnu.org/mirrors.html 8149 17. http://gcc.gnu.org/git.html 8150 18. https://gcc.gnu.org/onlinedocs/ 8151 19. mailto:gcc-help (a] gcc.gnu.org 8152 20. mailto:gcc (a] gcc.gnu.org 8153 21. https://gcc.gnu.org/lists.html 8154 22. https://www.fsf.org/ 8155 23. https://gcc.gnu.org/about.html 8156 ====================================================================== 8157 http://gcc.gnu.org/gcc-4.9/changes.html 8158 8159 GCC 4.9 Release Series 8160 Changes, New Features, and Fixes 8161 8162 Caveats 8163 8164 * The mudflap run time checker has been removed. The mudflap options 8165 remain, but do nothing. 8166 * Support for a number of older systems and recently unmaintained or 8167 untested target ports of GCC has been declared obsolete in GCC 4.9. 8168 Unless there is activity to revive them, the next release of GCC 8169 will have their sources permanently removed. 8170 The following ports for individual systems on particular 8171 architectures have been obsoleted: 8172 + Solaris 9 (*-*-solaris2.9). Details can be found in the 8173 [1]announcement. 8174 * On AArch64, the singleton vector types int64x1_t, uint64x1_t and 8175 float64x1_t exported by arm_neon.h are defined to be the same as 8176 their base types. This results in incorrect application of 8177 parameter passing rules to arguments of types int64x1_t and 8178 uint64x1_t, with respect to the AAPCS64 ABI specification. In 8179 addition, names of C++ functions with parameters of these types 8180 (including float64x1_t) are not mangled correctly. The current 8181 typedef declarations also unintentionally allow implicit casting 8182 between singleton vector types and their base types. These issues 8183 will be resolved in a near future release. See [2]PR60825 for more 8184 information. 8185 8186 More information on porting to GCC 4.9 from previous versions of GCC 8187 can be found in the [3]porting guide for this release. 8188 8189 General Optimizer Improvements 8190 8191 * AddressSanitizer, a fast memory error detector, is now available on 8192 ARM. 8193 * UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior 8194 detector, has been added and can be enabled via 8195 -fsanitize=undefined. Various computations will be instrumented to 8196 detect undefined behavior at runtime. UndefinedBehaviorSanitizer is 8197 currently available for the C and C++ languages. 8198 * Link-time optimization (LTO) improvements: 8199 + Type merging was rewritten. The new implementation is 8200 significantly faster and uses less memory. 8201 + Better partitioning algorithm resulting in less streaming 8202 during link time. 8203 + Early removal of virtual methods reduces the size of object 8204 files and improves link-time memory usage and compile time. 8205 + Function bodies are now loaded on-demand and released early 8206 improving overall memory usage at link time. 8207 + C++ hidden keyed methods can now be optimized out. 8208 + When using a linker plugin, compiling with the -flto option 8209 now generates slim object files (.o) which only contain 8210 intermediate language representation for LTO. Use 8211 -ffat-lto-objects to create files which contain additionally 8212 the object code. To generate static libraries suitable for LTO 8213 processing, use gcc-ar and gcc-ranlib; to list symbols from a 8214 slim object file use gcc-nm. (This requires that ar, ranlib 8215 and nm have been compiled with plugin support.) 8216 Memory usage building Firefox with debug enabled was reduced from 8217 15GB to 3.5GB; link time from 1700 seconds to 350 seconds. 8218 * Inter-procedural optimization improvements: 8219 + New type inheritance analysis module improving 8220 devirtualization. Devirtualization now takes into account 8221 anonymous name-spaces and the C++11 final keyword. 8222 + New speculative devirtualization pass (controlled by 8223 -fdevirtualize-speculatively. 8224 + Calls that were speculatively made direct are turned back to 8225 indirect where direct call is not cheaper. 8226 + Local aliases are introduced for symbols that are known to be 8227 semantically equivalent across shared libraries improving 8228 dynamic linking times. 8229 * Feedback directed optimization improvements: 8230 + Profiling of programs using C++ inline functions is now more 8231 reliable. 8232 + New time profiling determines typical order in which functions 8233 are executed. 8234 + A new function reordering pass (controlled by 8235 -freorder-functions) significantly reduces startup time of 8236 large applications. Until binutils support is completed, it is 8237 effective only with link-time optimization. 8238 + Feedback driven indirect call removal and devirtualization now 8239 handle cross-module calls when link-time optimization is 8240 enabled. 8241 8242 New Languages and Language specific improvements 8243 8244 * Version 4.0 of the [4]OpenMP specification is now supported in the 8245 C and C++ compilers and starting with the 4.9.1 release also in the 8246 Fortran compiler. The new -fopenmp-simd option can be used to 8247 enable OpenMP's SIMD directives while ignoring other OpenMP 8248 directives. The new [5]-fsimd-cost-model= option permits to tune 8249 the vectorization cost model for loops annotated with OpenMP and 8250 Cilk Plus simd directives. -Wopenmp-simd warns when the current 8251 cost model overrides simd directives set by the user. 8252 * The -Wdate-time option has been added for the C, C++ and Fortran 8253 compilers, which warns when the __DATE__, __TIME__ or __TIMESTAMP__ 8254 macros are used. Those macros might prevent bit-wise-identical 8255 reproducible compilations. 8256 8257 Ada 8258 8259 * GNAT switched to Ada 2012 instead of Ada 2005 by default. 8260 8261 C family 8262 8263 * Support for colorizing diagnostics emitted by GCC has been added. 8264 The [6]-fdiagnostics-color=auto will enable it when outputting to 8265 terminals, -fdiagnostics-color=always unconditionally. The 8266 GCC_COLORS environment variable can be used to customize the colors 8267 or disable coloring. If GCC_COLORS variable is present in the 8268 environment, the default is -fdiagnostics-color=auto, otherwise 8269 -fdiagnostics-color=never. 8270 Sample diagnostics output: 8271 $ g++ -fdiagnostics-color=always -S -Wall test.C 8272 test.C: In function `int foo()': 8273 test.C:1:14: warning: no return statement in function returning non-void [-W 8274 return-type] 8275 int foo () { } 8276 ^ 8277 test.C:2:46: error: template instantiation depth exceeds maximum of 900 (use 8278 -ftemplate-depth= to increase the maximum) instantiating `struct X<100>' 8279 template <int N> struct X { static const int value = X<N-1>::value; }; temp 8280 late struct X<1000>; 8281 ^ 8282 test.C:2:46: recursively required from `const int X<999>::value' 8283 test.C:2:46: required from `const int X<1000>::value' 8284 test.C:2:88: required from here 8285 8286 test.C:2:46: error: incomplete type `X<100>' used in nested name specifier 8287 8288 * With the new [7]#pragma GCC ivdep, the user can assert that there 8289 are no loop-carried dependencies which would prevent concurrent 8290 execution of consecutive iterations using SIMD (single instruction 8291 multiple data) instructions. 8292 * Support for Cilk Plus has been added and can be enabled with the 8293 -fcilkplus option. Cilk Plus is an extension to the C and C++ 8294 languages to support data and task parallelism. The present 8295 implementation follows ABI version 1.2; all features but _Cilk_for 8296 have been implemented. 8297 8298 C 8299 8300 * ISO C11 atomics (the _Atomic type specifier and qualifier and the 8301 <stdatomic.h> header) are now supported. 8302 * ISO C11 generic selections (_Generic keyword) are now supported. 8303 * ISO C11 thread-local storage (_Thread_local, similar to GNU C 8304 __thread) is now supported. 8305 * ISO C11 support is now at a similar level of completeness to ISO 8306 C99 support: substantially complete modulo bugs, extended 8307 identifiers (supported except for corner cases when 8308 -fextended-identifiers is used), floating-point issues (mainly but 8309 not entirely relating to optional C99 features from Annexes F and 8310 G) and the optional Annexes K (Bounds-checking interfaces) and L 8311 (Analyzability). 8312 * A new C extension __auto_type provides a subset of the 8313 functionality of C++11 auto in GNU C. 8314 8315 C++ 8316 8317 * The G++ implementation of [8]C++1y return type deduction for normal 8318 functions has been updated to conform to [9]N3638, the proposal 8319 accepted into the working paper. Most notably, it adds 8320 decltype(auto) for getting decltype semantics rather than the 8321 template argument deduction semantics of plain auto: 8322 8323 int& f(); 8324 auto i1 = f(); // int 8325 decltype(auto) i2 = f(); // int& 8326 8327 * G++ supports [10]C++1y lambda capture initializers: 8328 8329 [x = 42]{ ... }; 8330 8331 Actually, they have been accepted since GCC 4.5, but now the 8332 compiler doesn't warn about them with -std=c++1y, and supports 8333 parenthesized and brace-enclosed initializers as well. 8334 * G++ supports [11]C++1y variable length arrays. G++ has supported 8335 GNU/C99-style VLAs for a long time, but now additionally supports 8336 initializers and lambda capture by reference. In C++1y mode G++ 8337 will complain about VLA uses that are not permitted by the draft 8338 standard, such as forming a pointer to VLA type or applying sizeof 8339 to a VLA variable. Note that it now appears that VLAs will not be 8340 part of C++14, but will be part of a separate document and then 8341 perhaps C++17. 8342 8343 void f(int n) { 8344 int a[n] = { 1, 2, 3 }; // throws std::bad_array_length if n < 3 8345 [&a]{ for (int i : a) { cout << i << endl; } }(); 8346 &a; // error, taking address of VLA 8347 } 8348 8349 * G++ supports the [12]C++1y [[deprecated]] attribute modulo bugs in 8350 the underlying [[gnu::deprecated]] attribute. Classes and functions 8351 can be marked deprecated and a diagnostic message added: 8352 8353 class A; 8354 int bar(int n); 8355 #if __cplusplus > 201103 8356 class [[deprecated("A is deprecated in C++14; Use B instead")]] A; 8357 [[deprecated("bar is unsafe; use foo() instead")]] 8358 int bar(int n); 8359 8360 int foo(int n); 8361 class B; 8362 #endif 8363 A aa; // warning: 'A' is deprecated : A is deprecated in C++14; Use B instead 8364 int j = bar(2); // warning: 'int bar(int)' is deprecated : bar is unsafe; use fo 8365 o() instead 8366 8367 * G++ supports [13]C++1y digit separators. Long numeric literals can 8368 be subdivided with a single quote ' to enhance readability: 8369 8370 int i = 1048576; 8371 int j = 1'048'576; 8372 int k = 0x10'0000; 8373 int m = 0'004'000'000; 8374 int n = 0b0001'0000'0000'0000'0000'0000; 8375 8376 double x = 1.602'176'565e-19; 8377 double y = 1.602'176'565e-1'9; 8378 8379 * G++ supports [14]C++1y generic (polymorphic) lambdas. 8380 8381 // a functional object that will increment any type 8382 auto incr = [](auto x) { return x++; }; 8383 8384 * As a GNU extension, G++ supports explicit template parameter syntax 8385 for generic lambdas. This can be combined in the expected way with 8386 the standard auto syntax. 8387 8388 // a functional object that will add two like-type objects 8389 auto add = [] <typename T> (T a, T b) { return a + b; }; 8390 8391 * G++ supports unconstrained generic functions as specified by 4.1.2 8392 and 5.1.1 of [15]N3889: Concepts Lite Specification. Briefly, auto 8393 may be used as a type-specifier in a parameter declaration of any 8394 function declarator in order to introduce an implicit function 8395 template parameter, akin to generic lambdas. 8396 8397 // the following two function declarations are equivalent 8398 auto incr(auto x) { return x++; } 8399 template <typename T> 8400 auto incr(T x) { return x++; } 8401 8402 Runtime Library (libstdc++) 8403 8404 * [16]Improved support for C++11, including: 8405 + support for <regex>; 8406 + The associative containers in <map> and <set> and the 8407 unordered associative containers in <unordered_map> and 8408 <unordered_set> meet the allocator-aware container 8409 requirements; 8410 * [17]Improved experimental support for the upcoming ISO C++ 8411 standard, C++14, including: 8412 + fixing constexpr member functions without const; 8413 + implementation of the std::exchange() utility function; 8414 + addressing tuples by type; 8415 + implemention of std::make_unique; 8416 + implemention of std::shared_lock; 8417 + making std::result_of SFINAE-friendly; 8418 + adding operator() to std::integral_constant; 8419 + adding user-defined literals for standard library types 8420 std::basic_string, std::chrono::duration, and std::complex; 8421 + adding two range overloads to non-modifying sequence oprations 8422 std::equal and std::mismatch; 8423 + adding IO manipulators for quoted strings; 8424 + adding constexpr members to <utility>, <complex>, <chrono>, 8425 and some containers; 8426 + adding compile-time std::integer_sequence; 8427 + adding cleaner transformation traits; 8428 + making <functional>s operator functors easier to use and more 8429 generic; 8430 * An implementation of std::experimental::optional. 8431 * An implementation of std::experimental::string_view. 8432 * The non-standard function std::copy_exception has been deprecated 8433 and will be removed in a future version. std::make_exception_ptr 8434 should be used instead. 8435 8436 Fortran 8437 8438 * Compatibility notice: 8439 + Module files: The version of the module files (.mod) has been 8440 incremented; additionally, module files are now compressed. 8441 Fortran MODULEs compiled by earlier GCC versions have to be 8442 recompiled, when they are USEd by files compiled with GCC 4.9. 8443 GCC 4.9 is not able to read .mod files of earlier GCC 8444 versions; attempting to do so gives an error message. Note: 8445 The ABI of the produced assembler data itself has not changed: 8446 object files and libraries are fully compatible with older 8447 versions (except as stated below). 8448 + ABI changes: 8449 o The [18]argument passing ABI has changed for scalar dummy 8450 arguments of type INTEGER, REAL, COMPLEX and LOGICAL, 8451 which have both the VALUE and the OPTIONAL attributes. 8452 o To support finalization the virtual table associated with 8453 polymorphic variables has changed. Code containing CLASS 8454 should be recompiled, including all files which define 8455 derived types involved in the type definition used by 8456 polymorphic variables. (Note: Due to the incremented 8457 module version, trying to mix old code with new code will 8458 usually give an error message.) 8459 + GNU Fortran no longer deallocates allocatable variables or 8460 allocatable components of variables declared in the main 8461 program. Since Fortran 2008, the standard explicitly states 8462 that variables declared in the Fortran main program 8463 automatically have the SAVE attribute. 8464 + When opening files, the close-on-exec flag is set if the 8465 system supports such a feature. This is generally considered 8466 good practice these days, but if there is a need to pass file 8467 descriptors to child processes the parent process must now 8468 remember to clear the close-on-exec flag by calling fcntl(), 8469 e.g. via ISO_C_BINDING, before executing the child process. 8470 * The deprecated command-line option -fno-whole-file has been 8471 removed. (-fwhole-file is the default since GCC 4.6.) 8472 -fwhole-file/-fno-whole-file continue to be accepted but do not 8473 influence the code generation. 8474 * The compiler no longer unconditionally warns about DO loops with 8475 zero iterations. This warning is now controlled by the -Wzerotrip 8476 option, which is implied by -Wall. 8477 * The new NO_ARG_CHECK attribute of the [19]!GCC$ directive can be 8478 used to disable the type-kind-rank (TKR) argument check for a dummy 8479 argument. The feature is similar to ISO/IEC TS 29133:2012's 8480 TYPE(*), except that it additionally also disables the rank check. 8481 Variables with NO_ARG_CHECK have to be dummy arguments and may only 8482 be used as argument to ISO_C_BINDING's C_LOC and as actual argument 8483 to another NO_ARG_CHECK dummy argument; also the other constraints 8484 of TYPE(*) apply. The dummy arguments should be declared as scalar 8485 or assumed-size variable of type type(*) (recommended) - or of type 8486 integer, real, complex or logical. With NO_ARG_CHECK, a pointer to 8487 the data without further type or shape information is passed, 8488 similar to C's void*. Note that also TS 29113's 8489 type(*),dimension(..) accepts arguments of any type and rank; 8490 contrary to NO_ARG_CHECK assumed-rank arguments pass an array 8491 descriptor which contains the array shape and stride of the 8492 argument. 8493 * [20]Fortran 2003: 8494 + Finalization is now supported. It is currently only done for a 8495 subset of those situations in which it should occur. 8496 + Experimental support for scalar character components with 8497 deferred length (i.e. allocatable string length) in derived 8498 types has been added. (Deferred-length character variables are 8499 supported since GCC 4.6.) 8500 * [21]Fortran 2008: 8501 + When STOP or ERROR STOP are used to terminate the execution 8502 and any exception (but inexact) is signaling, a warning is 8503 printed to ERROR_UNIT, indicating which exceptions are 8504 signaling. The [22]-ffpe-summary= command-line option can be 8505 used to fine-tune for which exceptions the warning should be 8506 shown. 8507 + Rounding on input (READ) is now handled on systems where 8508 strtod honours the rounding mode. (For output, rounding is 8509 supported since GCC 4.5.) Note that for input, the compatible 8510 rounding mode is handled as nearest (i.e., rounding to an even 8511 least significant [cf. IEC 60559:1989] for a tie, while 8512 compatible rounds away from zero in that case). 8513 8514 Go 8515 8516 * GCC 4.9 provides a complete implementation of the Go 1.2.1 release. 8517 8518 New Targets and Target Specific Improvements 8519 8520 AArch64 8521 8522 * The ARMv8-A crypto and CRC instructions are now supported through 8523 intrinsics. These are enabled when the architecture supports these 8524 and are available through the -march=armv8-a+crc and 8525 -march=armv8-a+crypto options. 8526 * Initial support for ILP32 has now been added to the compiler. This 8527 is now available through the command-line option -mabi=ilp32. 8528 Support for ILP32 is considered experimental as the ABI 8529 specification is still beta. 8530 * Coverage of more of the ISA including the SIMD extensions has been 8531 added. The Advanced SIMD intrinsics have also been improved. 8532 * The new local register allocator (LRA) is now on by default for the 8533 AArch64 backend. 8534 * The REE (Redundant extension elimination) pass has now been enabled 8535 by default for the AArch64 backend. 8536 * Tuning for the Cortex-A53 and Cortex-A57 has been improved. 8537 * Initial big.LITTLE tuning support for the combination of Cortex-A57 8538 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 8539 option. 8540 * A number of structural changes have been made to both the ARM and 8541 AArch64 backends to facilitate improved code-generation. 8542 * As of GCC 4.9.2 a workaround for the ARM Cortex-A53 erratum 835769 8543 has been added and can be enabled by giving the 8544 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 8545 default by configuring GCC with the --enable-fix-cortex-a53-835769 8546 option. 8547 8548 ARC 8549 8550 * A port for Synopsys Designware ARC has been contributed by Embecosm 8551 and Synopsys Inc. 8552 8553 ARM 8554 8555 * Use of Advanced SIMD (Neon) for 64-bit scalar computations has been 8556 disabled by default. This was found to generate better code in only 8557 a small number of cases. It can be turned back on with the 8558 -mneon-for-64bits option. 8559 * Further support for the ARMv8-A architecture, notably implementing 8560 the restriction around IT blocks in the Thumb32 instruction set has 8561 been added. The -mrestrict-it option can be used with 8562 -march=armv7-a or the -march=armv7ve options to make code 8563 generation fully compatible with the deprecated instructions in 8564 ARMv8-A. 8565 * Support has now been added for the ARMv7ve variant of the 8566 architecture. This can be used by the -march=armv7ve option. 8567 * The ARMv8-A crypto and CRC instructions are now supported through 8568 intrinsics and are available through the -march=armv8-a+crc and 8569 mfpu=crypto-neon-fp-armv8 options. 8570 * LRA is now on by default for the ARM target. This can be turned off 8571 using the -mno-lra option. This option is a purely transitionary 8572 command-line option and will be removed in a future release. We are 8573 interested in any bug reports regarding functional and performance 8574 regressions with LRA. 8575 * A new option -mslow-flash-data to improve performance of programs 8576 fetching data on slow flash memory has now been introduced for the 8577 ARMv7-M profile cores. 8578 * A new option -mpic-data-is-text-relative for targets that allows 8579 data segments to be relative to text segments has been added. This 8580 is on by default for all targets except VxWorks RTP. 8581 * A number of infrastructural changes have been made to both the ARM 8582 and AArch64 backends to facilitate improved code-generation. 8583 * GCC now supports Cortex-A12 and the Cortex-R7 through the 8584 -mcpu=cortex-a12 and -mcpu=cortex-r7 options. 8585 * GCC now has tuning for the Cortex-A57 and Cortex-A53 through the 8586 -mcpu=cortex-a57 and -mcpu=cortex-a53 options. 8587 * Initial big.LITTLE tuning support for the combination of Cortex-A57 8588 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 8589 option. Similar support was added for the combination of Cortex-A15 8590 and Cortex-A7 through the -mcpu=cortex-a15.cortex-a7 option. 8591 * Further performance optimizations for the Cortex-A15 and the 8592 Cortex-M4 have been added. 8593 * A number of code generation improvements for Thumb2 to reduce code 8594 size when compiling for the M-profile processors. 8595 8596 AVR 8597 8598 * A new command-line option -mfract-convert-truncate has been added. 8599 It allows compiler to use truncation instead of rounding towards 8600 zero for fractional fixed-point types. 8601 8602 IA-32/x86-64 8603 8604 * -mfpmath=sse is now implied by -ffast-math on all targets where 8605 SSE2 is supported. 8606 * Intel AVX-512 support was added to GCC. That includes inline 8607 assembly support, new registers and extending existing ones, new 8608 intrinsics (covered by corresponding testsuite), and basic 8609 autovectorization. AVX-512 instructions are available via the 8610 following GCC switches: AVX-512 foundation instructions: -mavx512f, 8611 AVX-512 prefetch instructions: -mavx512pf, AVX-512 exponential and 8612 reciprocal instructions: -mavx512er, AVX-512 conflict detection 8613 instructions: -mavx512cd. 8614 * It is now possible to call x86 intrinsics from select functions in 8615 a file that are tagged with the corresponding target attribute 8616 without having to compile the entire file with the -mxxx option. 8617 This improves the usability of x86 intrinsics and is particularly 8618 useful when doing [23]Function Multiversioning. 8619 * GCC now supports the new Intel microarchitecture named Silvermont 8620 through -march=silvermont. 8621 * GCC now supports the new Intel microarchitecture named Broadwell 8622 through -march=broadwell. 8623 * Optimizing for other Intel microarchitectures have been renamed to 8624 -march=nehalem, westmere, sandybridge, ivybridge, haswell, bonnell. 8625 * -march=generic has been retuned for better support of Intel core 8626 and AMD Bulldozer architectures. Performance of AMD K7, K8, Intel 8627 Pentium-M, and Pentium4 based CPUs is no longer considered 8628 important for generic. 8629 * -mtune=intel can now be used to generate code running well on the 8630 most current Intel processors, which are Haswell and Silvermont for 8631 GCC 4.9. 8632 * Support to encode 32-bit assembly instructions in 16-bit format is 8633 now available through the -m16 command-line option. 8634 * Better inlining of memcpy and memset that is aware of value ranges 8635 and produces shorter alignment prologues. 8636 * -mno-accumulate-outgoing-args is now honored when unwind 8637 information is output. Argument accumulation is also now turned off 8638 for portions of programs optimized for size. 8639 * Support for new AMD family 15h processors (Excavator core) is now 8640 available through the -march=bdver4 and -mtune=bdver4 options. 8641 8642 MSP430 8643 8644 * A new command-line option -mcpu= has been added to the MSP430 8645 backend. This option is used to specify the ISA to be used. 8646 Accepted values are msp430 (the default), msp430x and msp430xv2. 8647 The ISA is no longer deduced from the -mmcu= option as there are 8648 far too many different MCU names. The -mmcu= option is still 8649 supported, and this is still used to select linker scripts and 8650 generate a C preprocessor symbol that will be recognised by the 8651 msp430.h header file. 8652 8653 NDS32 8654 8655 * A new nds32 port supports the 32-bit architecture from Andes 8656 Technology Corporation. 8657 * The port provides initial support for the V2, V3, V3m instruction 8658 set architectures. 8659 8660 Nios II 8661 8662 * A port for the Altera Nios II has been contributed by Mentor 8663 Graphics. 8664 8665 PowerPC / PowerPC64 / RS6000 8666 8667 * GCC now supports Power ISA 2.07, which includes support for 8668 Hardware Transactional Memory (HTM), Quadword atomics and several 8669 VMX and VSX additions, including Crypto, 64-bit integer, 128-bit 8670 integer and decimal integer operations. 8671 * Support for the POWER8 processor is now available through the 8672 -mcpu=power8 and -mtune=power8 options. 8673 * The libitm library has been modified to add a HTM fastpath that 8674 automatically uses POWER's HTM hardware instructions when it is 8675 executing on a HTM enabled processor. 8676 * Support for the new powerpc64le-linux platform has been added. It 8677 defaults to generating code that conforms to the ELFV2 ABI. 8678 8679 S/390, System z 8680 8681 * Support for the Transactional Execution Facility included with the 8682 IBM zEnterprise zEC12 processor has been added. A set of GCC style 8683 builtins as well as XLC style builtins are provided. The builtins 8684 are enabled by default when using the -march=zEC12 option but can 8685 explicitly be disabled with -mno-htm. Using the GCC builtins also 8686 libitm supports hardware transactions on S/390. 8687 * The hotpatch features allows to prepare functions for hotpatching. 8688 A certain amount of bytes is reserved before the function entry 8689 label plus a NOP is inserted at its very beginning to implement a 8690 backward jump when applying a patch. The feature can either be 8691 enabled per compilation unit via the command-line option -mhotpatch 8692 or per function using the hotpatch attribute. 8693 * The shrink wrap optimization is now supported on S/390 and enabled 8694 by default. 8695 * A major rework of the routines to determine which registers need to 8696 be saved and restored in function prologue/epilogue now allow to 8697 use floating point registers as save slots. This will happen for 8698 certain leaf function with -march=z10 or higher. 8699 * The LRA rtl pass replaces reload by default on S/390. 8700 8701 RX 8702 8703 * The port now allows to specify the RX100, RX200, and RX600 8704 processors with the command-line options -mcpu=rx100, -mcpu=rx200 8705 and -mcpu=rx600. 8706 8707 SH 8708 8709 * Minor improvements to code generated for integer arithmetic and 8710 code that involves the T bit. 8711 * Added support for the SH2A clips and clipu instructions. The 8712 compiler will now try to utilize them for min/max expressions such 8713 as max (-128, min (127, x)). 8714 * Added support for the cmp/str instruction through built-in 8715 functions such as __builtin_strlen. When not optimizing for size, 8716 the compiler will now expand calls to e.g. strlen as an inlined 8717 sequences which utilize the cmp/str instruction. 8718 * Improved code generated around volatile memory loads and stores. 8719 * The option -mcbranchdi has been deprecated. Specifying it will 8720 result in a warning and will not influence code generation. 8721 * The option -mcmpeqdi has been deprecated. Specifying it will result 8722 in a warning and will not influence code generation. 8723 8724 GCC 4.9.1 8725 8726 This is the [24]list of problem reports (PRs) from GCC's bug tracking 8727 system that are known to be fixed in the 4.9.1 release. This list might 8728 not be complete (that is, it is possible that some PRs that have been 8729 fixed are not listed here). 8730 8731 Version 4.0 of the OpenMP specification is supported even in Fortran, 8732 not just C and C++. 8733 8734 GCC 4.9.2 8735 8736 This is the [25]list of problem reports (PRs) from GCC's bug tracking 8737 system that are known to be fixed in the 4.9.2 release. This list might 8738 not be complete (that is, it is possible that some PRs that have been 8739 fixed are not listed here). 8740 8741 GCC 4.9.3 8742 8743 This is the [26]list of problem reports (PRs) from GCC's bug tracking 8744 system that are known to be fixed in the 4.9.3 release. This list might 8745 not be complete (that is, it is possible that some PRs that have been 8746 fixed are not listed here). 8747 8748 GCC 4.9.4 8749 8750 This is the [27]list of problem reports (PRs) from GCC's bug tracking 8751 system that are known to be fixed in the 4.9.4 release. This list might 8752 not be complete (that is, it is possible that some PRs that have been 8753 fixed are not listed here). 8754 8755 8756 For questions related to the use of GCC, please consult these web 8757 pages and the [28]GCC manuals. If that fails, the 8758 [29]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8759 web pages and the development of GCC are welcome on our developer 8760 list at [30]gcc (a] gcc.gnu.org. All of [31]our lists have public 8761 archives. 8762 8763 Copyright (C) [32]Free Software Foundation, Inc. Verbatim copying and 8764 distribution of this entire article is permitted in any medium, 8765 provided this notice is preserved. 8766 8767 These pages are [33]maintained by the GCC team. Last modified 8768 2023-01-19. 8769 8770 References 8771 8772 1. https://gcc.gnu.org/ml/gcc-patches/2013-05/msg00728.html 8773 2. https://gcc.gnu.org/PR60825 8774 3. https://gcc.gnu.org/gcc-4.9/porting_to.html 8775 4. https://www.openmp.org/specifications/ 8776 5. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Optimize-Options.html#index-fsimd-cost-model-908 8777 6. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Language-Independent-Options.html#index-fdiagnostics-color-252 8778 7. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Loop-Specific-Pragmas.html 8779 8. http://gcc.gnu.org/projects/cxx1y.html 8780 9. https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3638.html 8781 10. http://gcc.gnu.org/projects/cxx1y.html 8782 11. http://gcc.gnu.org/projects/cxx1y.html 8783 12. http://gcc.gnu.org/projects/cxx1y.html 8784 13. http://gcc.gnu.org/projects/cxx1y.html 8785 14. http://gcc.gnu.org/projects/cxx1y.html 8786 15. https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3889.pdf 8787 16. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/libstdc++/manual/manual/status.html#status.iso.2011 8788 17. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2014 8789 18. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Argument-passing-conventions.html 8790 19. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/GNU-Fortran-Compiler-Directives.html 8791 20. https://gcc.gnu.org/wiki/Fortran2003Status 8792 21. https://gcc.gnu.org/wiki/Fortran2008Status 8793 22. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Debugging-Options.html 8794 23. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Function-Multiversioning.html 8795 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.1 8796 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.2 8797 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.3 8798 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.4 8799 28. https://gcc.gnu.org/onlinedocs/ 8800 29. mailto:gcc-help (a] gcc.gnu.org 8801 30. mailto:gcc (a] gcc.gnu.org 8802 31. https://gcc.gnu.org/lists.html 8803 32. https://www.fsf.org/ 8804 33. https://gcc.gnu.org/about.html 8805 ====================================================================== 8806 http://gcc.gnu.org/gcc-4.8/index.html 8807 8808 GCC 4.8 Release Series 8809 8810 (This release series is no longer supported.) 8811 8812 June 23, 2015 8813 8814 The [1]GNU project and the GCC developers are pleased to announce the 8815 release of GCC 4.8.5. 8816 8817 This release is a bug-fix release, containing fixes for regressions in 8818 GCC 4.8.4 relative to previous releases of GCC. 8819 8820 Release History 8821 8822 GCC 4.8.5 8823 June 23, 2015 ([2]changes, [3]documentation) 8824 8825 GCC 4.8.4 8826 December 19, 2014 ([4]changes, [5]documentation) 8827 8828 GCC 4.8.3 8829 May 22, 2014 ([6]changes, [7]documentation) 8830 8831 GCC 4.8.2 8832 October 16, 2013 ([8]changes, [9]documentation) 8833 8834 GCC 4.8.1 8835 May 31, 2013 ([10]changes, [11]documentation) 8836 8837 GCC 4.8.0 8838 March 22, 2013 ([12]changes, [13]documentation) 8839 8840 References and Acknowledgements 8841 8842 GCC used to stand for the GNU C Compiler, but since the compiler 8843 supports several other languages aside from C, it now stands for the 8844 GNU Compiler Collection. 8845 8846 A list of [14]successful builds is updated as new information becomes 8847 available. 8848 8849 The GCC developers would like to thank the numerous people that have 8850 contributed new features, improvements, bug fixes, and other changes as 8851 well as test results to GCC. This [15]amazing group of volunteers is 8852 what makes GCC successful. 8853 8854 For additional information about GCC please refer to the [16]GCC 8855 project web site or contact the [17]GCC development mailing list. 8856 8857 To obtain GCC please use [18]our mirror sites or [19]our version 8858 control system. 8859 8860 8861 For questions related to the use of GCC, please consult these web 8862 pages and the [20]GCC manuals. If that fails, the 8863 [21]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8864 web pages and the development of GCC are welcome on our developer 8865 list at [22]gcc (a] gcc.gnu.org. All of [23]our lists have public 8866 archives. 8867 8868 Copyright (C) [24]Free Software Foundation, Inc. Verbatim copying and 8869 distribution of this entire article is permitted in any medium, 8870 provided this notice is preserved. 8871 8872 These pages are [25]maintained by the GCC team. Last modified 8873 2022-10-26. 8874 8875 References 8876 8877 1. http://www.gnu.org/ 8878 2. http://gcc.gnu.org/gcc-4.8/changes.html 8879 3. https://gcc.gnu.org/onlinedocs/4.8.5/ 8880 4. http://gcc.gnu.org/gcc-4.8/changes.html 8881 5. https://gcc.gnu.org/onlinedocs/4.8.4/ 8882 6. http://gcc.gnu.org/gcc-4.8/changes.html 8883 7. https://gcc.gnu.org/onlinedocs/4.8.3/ 8884 8. http://gcc.gnu.org/gcc-4.8/changes.html 8885 9. https://gcc.gnu.org/onlinedocs/4.8.2/ 8886 10. http://gcc.gnu.org/gcc-4.8/changes.html 8887 11. https://gcc.gnu.org/onlinedocs/4.8.1/ 8888 12. http://gcc.gnu.org/gcc-4.8/changes.html 8889 13. https://gcc.gnu.org/onlinedocs/4.8.0/ 8890 14. http://gcc.gnu.org/gcc-4.8/buildstat.html 8891 15. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 8892 16. http://gcc.gnu.org/index.html 8893 17. mailto:gcc (a] gcc.gnu.org 8894 18. http://gcc.gnu.org/mirrors.html 8895 19. http://gcc.gnu.org/git.html 8896 20. https://gcc.gnu.org/onlinedocs/ 8897 21. mailto:gcc-help (a] gcc.gnu.org 8898 22. mailto:gcc (a] gcc.gnu.org 8899 23. https://gcc.gnu.org/lists.html 8900 24. https://www.fsf.org/ 8901 25. https://gcc.gnu.org/about.html 8902 ====================================================================== 8903 http://gcc.gnu.org/gcc-4.8/changes.html 8904 8905 GCC 4.8 Release Series 8906 Changes, New Features, and Fixes 8907 8908 Caveats 8909 8910 GCC now uses C++ as its implementation language. This means that to 8911 build GCC from sources, you will need a C++ compiler that understands 8912 C++ 2003. For more details on the rationale and specific changes, 8913 please refer to the [1]C++ conversion page. 8914 8915 To enable the Graphite framework for loop optimizations you now need 8916 CLooG version 0.18.0 and ISL version 0.11.1. Both can be obtained from 8917 the [2]GCC infrastructure directory. The installation manual contains 8918 more information about requirements to build GCC. 8919 8920 GCC now uses a more aggressive analysis to derive an upper bound for 8921 the number of iterations of loops using constraints imposed by language 8922 standards. This may cause non-conforming programs to no longer work as 8923 expected, such as SPEC CPU 2006 464.h264ref and 416.gamess. A new 8924 option, -fno-aggressive-loop-optimizations, was added to disable this 8925 aggressive analysis. In some loops that have known constant number of 8926 iterations, but undefined behavior is known to occur in the loop before 8927 reaching or during the last iteration, GCC will warn about the 8928 undefined behavior in the loop instead of deriving lower upper bound of 8929 the number of iterations for the loop. The warning can be disabled with 8930 -Wno-aggressive-loop-optimizations. 8931 8932 On ARM, a bug has been fixed in GCC's implementation of the AAPCS rules 8933 for the layout of vectors that could lead to wrong code being 8934 generated. Vectors larger than 8 bytes in size are now by default 8935 aligned to an 8-byte boundary. This is an ABI change: code that makes 8936 explicit use of vector types may be incompatible with binary objects 8937 built with older versions of GCC. Auto-vectorized code is not affected 8938 by this change. 8939 8940 On AVR, support has been removed for the command-line option 8941 -mshort-calls deprecated in GCC 4.7. 8942 8943 On AVR, the configure option --with-avrlibc supported since GCC 4.7.2 8944 is turned on per default for all non-RTEMS configurations. This option 8945 arranges for a better integration of [3]AVR Libc with avr-gcc. For 8946 technical details, see [4]PR54461. To turn off the option in non-RTEMS 8947 configurations, use --with-avrlibc=no. If the compiler is configured 8948 for RTEMS, the option is always turned off. 8949 8950 More information on porting to GCC 4.8 from previous versions of GCC 8951 can be found in the [5]porting guide for this release. 8952 8953 General Optimizer Improvements (and Changes) 8954 8955 * DWARF4 is now the default when generating DWARF debug information. 8956 When -g is used on a platform that uses DWARF debugging 8957 information, GCC will now default to -gdwarf-4 8958 -fno-debug-types-section. 8959 GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information 8960 consumers support DWARF4 by default. Before GCC 4.8 the default 8961 version used was DWARF2. To make GCC 4.8 generate an older DWARF 8962 version use -g together with -gdwarf-2 or -gdwarf-3. The default 8963 for Darwin and VxWorks is still -gdwarf-2 -gstrict-dwarf. 8964 * A new general optimization level, -Og, has been introduced. It 8965 addresses the need for fast compilation and a superior debugging 8966 experience while providing a reasonable level of run-time 8967 performance. Overall experience for development should be better 8968 than the default optimization level -O0. 8969 * A new option -ftree-partial-pre was added to control the partial 8970 redundancy elimination (PRE) optimization. This option is enabled 8971 by default at the -O3 optimization level, and it makes PRE more 8972 aggressive. 8973 * The option -fconserve-space has been removed; it was no longer 8974 useful on most targets since GCC supports putting variables into 8975 BSS without making them common. 8976 * The struct reorg and matrix reorg optimizations (command-line 8977 options -fipa-struct-reorg and -fipa-matrix-reorg) have been 8978 removed. They did not always work correctly, nor did they work with 8979 link-time optimization (LTO), hence were only applicable to 8980 programs consisting of a single translation unit. 8981 * Several scalability bottle-necks have been removed from GCC's 8982 optimization passes. Compilation of extremely large functions, e.g. 8983 due to the use of the flatten attribute in the "Eigen" C++ linear 8984 algebra templates library, is significantly faster than previous 8985 releases of GCC. 8986 * Link-time optimization (LTO) improvements: 8987 + LTO partitioning has been rewritten for better reliability and 8988 maintanibility. Several important bugs leading to link 8989 failures have been fixed. 8990 * Interprocedural optimization improvements: 8991 + A new symbol table has been implemented. It builds on existing 8992 callgraph and varpool modules and provide a new API. Unusual 8993 symbol visibilities and aliases are handled more consistently 8994 leading to, for example, more aggressive unreachable code 8995 removal with LTO. 8996 + The inline heuristic can now bypass limits on the size of of 8997 inlined functions when the inlining is particularly 8998 profitable. This happens, for example, when loop bounds or 8999 array strides get propagated. 9000 + Values passed through aggregates (either by value or 9001 reference) are now propagated at the inter-procedural level 9002 leading to better inlining decisions (for example in the case 9003 of Fortran array descriptors) and devirtualization. 9004 * [6]AddressSanitizer , a fast memory error detector, has been added 9005 and can be enabled via -fsanitize=address. Memory access 9006 instructions will be instrumented to detect heap-, stack-, and 9007 global-buffer overflow as well as use-after-free bugs. To get nicer 9008 stacktraces, use -fno-omit-frame-pointer. The AddressSanitizer is 9009 available on IA-32/x86-64/x32/PowerPC/PowerPC64 GNU/Linux and on 9010 x86-64 Darwin. 9011 * [7]ThreadSanitizer has been added and can be enabled via 9012 -fsanitize=thread. Instructions will be instrumented to detect data 9013 races. The ThreadSanitizer is available on x86-64 GNU/Linux. 9014 * A new local register allocator (LRA) has been implemented, which 9015 replaces the 26 year old reload pass and improves generated code 9016 quality. For now it is active on the IA-32 and x86-64 targets. 9017 * Support for transactional memory has been implemented on the 9018 following architectures: IA-32/x86-64, ARM, PowerPC, SH, SPARC, and 9019 Alpha. 9020 9021 New Languages and Language specific improvements 9022 9023 C family 9024 9025 * Each diagnostic emitted now includes the original source line and a 9026 caret '^' indicating the column. The option 9027 -fno-diagnostics-show-caret suppresses this information. 9028 * The option -ftrack-macro-expansion=2 is now enabled by default. 9029 This allows the compiler to display the macro expansion stack in 9030 diagnostics. Combined with the caret information, an example 9031 diagnostic showing these two features is: 9032 9033 t.c:1:94: error: invalid operands to binary < (have `struct mystruct' and `float 9034 ') 9035 #define MYMAX(A,B) __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) _ 9036 _b = (B); __a < __b ? __b : __a; }) 9037 9038 ^ 9039 t.c:7:7: note: in expansion of macro 'MYMAX' 9040 X = MYMAX(P, F); 9041 ^ 9042 9043 * A new -Wsizeof-pointer-memaccess warning has been added (also 9044 enabled by -Wall) to warn about suspicious length parameters to 9045 certain string and memory built-in functions if the argument uses 9046 sizeof. This warning warns e.g. about memset (ptr, 0, sizeof 9047 (ptr)); if ptr is not an array, but a pointer, and suggests a 9048 possible fix, or about memcpy (&foo, ptr, sizeof (&foo));. 9049 * The new option -Wpedantic is an alias for -pedantic, which is now 9050 deprecated. The forms -Wno-pedantic, -Werror=pedantic, and 9051 -Wno-error=pedantic work in the same way as for any other -W 9052 option. One caveat is that -Werror=pedantic is not equivalent to 9053 -pedantic-errors, since the latter makes into errors some warnings 9054 that are not controlled by -Wpedantic, and the former only affects 9055 diagnostics that are disabled when using -Wno-pedantic. 9056 * The option -Wshadow no longer warns if a declaration shadows a 9057 function declaration, unless the former declares a function or 9058 pointer to function, because this is [8]a common and valid case in 9059 real-world code. 9060 9061 C++ 9062 9063 * G++ now implements the [9]C++11 thread_local keyword; this differs 9064 from the GNU __thread keyword primarily in that it allows dynamic 9065 initialization and destruction semantics. Unfortunately, this 9066 support requires a run-time penalty for references to 9067 non-function-local thread_local variables defined in a different 9068 translation unit even if they don't need dynamic initialization, so 9069 users may want to continue to use __thread for TLS variables with 9070 static initialization semantics. 9071 If the programmer can be sure that no use of the variable in a 9072 non-defining TU needs to trigger dynamic initialization (either 9073 because the variable is statically initialized, or a use of the 9074 variable in the defining TU will be executed before any uses in 9075 another TU), they can avoid this overhead with the 9076 -fno-extern-tls-init option. 9077 OpenMP threadprivate variables now also support dynamic 9078 initialization and destruction by the same mechanism. 9079 * G++ now implements the [10]C++11 attribute syntax, e.g. 9080 9081 [[noreturn]] void f(); 9082 9083 and also the alignment specifier, e.g. 9084 9085 alignas(double) int i; 9086 9087 * G++ now implements [11]C++11 inheriting constructors, e.g. 9088 9089 struct A { A(int); }; 9090 struct B: A { using A::A; }; // defines B::B(int) 9091 B b(42); // OK 9092 9093 * As of GCC 4.8.1, G++ implements the change to decltype semantics 9094 from [12]N3276. 9095 9096 struct A f(); 9097 decltype(f()) g(); // OK, return type of f() is not required to be complete. 9098 9099 * As of GCC 4.8.1, G++ implements [13]C++11 ref-qualifiers, e.g. 9100 9101 struct A { int f() &; }; 9102 int i = A().f(); // error, f() requires an lvalue object 9103 9104 * G++ now supports a -std=c++1y option for experimentation with 9105 features proposed for the next revision of the standard, expected 9106 around 2014. Currently the only difference from -std=c++11 is 9107 support for return type deduction in normal functions, as proposed 9108 in [14]N3386. Status of C++1y features in GCC 4.8 can be found 9109 [15]here. 9110 * The G++ namespace association extension, __attribute ((strong)), 9111 has been deprecated. Inline namespaces should be used instead. 9112 * G++ now supports a -fext-numeric-literal option to control whether 9113 GNU numeric literal suffixes are accepted as extensions or 9114 processed as C++11 user-defined numeric literal suffixes. The flag 9115 is on (use suffixes for GNU literals) by default for -std=gnu++*, 9116 and -std=c++98. The flag is off (use suffixes for user-defined 9117 literals) by default for -std=c++11 and later. 9118 9119 Runtime Library (libstdc++) 9120 9121 * [16]Improved experimental support for the new ISO C++ standard, 9122 C++11, including: 9123 + forward_list meets the allocator-aware container requirements; 9124 + this_thread::sleep_for(), this_thread::sleep_until() and 9125 this_thread::yield() are defined without requiring the 9126 configure option --enable-libstdcxx-time; 9127 * Improvements to <random>: 9128 + SSE optimized normal_distribution. 9129 + Use of hardware RNG instruction for random_device on new x86 9130 processors (requires the assembler to support the 9131 instruction.) 9132 and <ext/random>: 9133 + New random number engine simd_fast_mersenne_twister_engine 9134 with an optimized SSE implementation. 9135 + New random number distributions beta_distribution, 9136 normal_mv_distribution, rice_distribution, 9137 nakagami_distribution, pareto_distribution, k_distribution, 9138 arcsine_distribution, hoyt_distribution. 9139 * Added --disable-libstdcxx-verbose configure option to disable 9140 diagnostic messages issued when a process terminates abnormally. 9141 This may be useful for embedded systems to reduce the size of 9142 executables that link statically to the library. 9143 9144 Fortran 9145 9146 * Compatibility notice: 9147 + Module files: The version of module files (.mod) has been 9148 incremented. Fortran MODULEs compiled by earlier GCC versions 9149 have to be recompiled, when they are USEd by files compiled 9150 with GCC 4.8. GCC 4.8 is not able to read .mod files created 9151 by earlier versions; attempting to do so gives an error 9152 message. 9153 Note: The ABI of the produced assembler data itself has not 9154 changed; object files and libraries are fully compatible with 9155 older versions except as noted below. 9156 + ABI: Some internal names (used in the assembler/object file) 9157 have changed for symbols declared in the specification part of 9158 a module. If an affected module - or a file using it via use 9159 association - is recompiled, the module and all files which 9160 directly use such symbols have to be recompiled as well. This 9161 change only affects the following kind of module symbols: 9162 o Procedure pointers. Note: C-interoperable function 9163 pointers (type(c_funptr)) are not affected nor are 9164 procedure-pointer components. 9165 o Deferred-length character strings. 9166 * The [17]BACKTRACE intrinsic subroutine has been added. It shows a 9167 backtrace at an arbitrary place in user code; program execution 9168 continues normally afterwards. 9169 * The [18]-Wc-binding-type warning option has been added (disabled by 9170 default). It warns if the a variable might not be C interoperable; 9171 in particular, if the variable has been declared using an intrinsic 9172 type with default kind instead of using a kind parameter defined 9173 for C interoperability in the intrinsic ISO_C_Binding module. 9174 Before, this warning was always printed. The -Wc-binding-type 9175 option is enabled by -Wall. 9176 * The [19]-Wrealloc-lhs and -Wrealloc-lhs-all warning command-line 9177 options have been added, which diagnose when code is inserted for 9178 automatic (re)allocation of a variable during assignment. This 9179 option can be used to decide whether it is safe to use 9180 [20]-fno-realloc-lhs. Additionally, it can be used to find 9181 automatic (re)allocation in hot loops. (For arrays, replacing 9182 "var=" by "var(:)=" disables the automatic reallocation.) 9183 * The [21]-Wcompare-reals command-line option has been added. When 9184 this is set, warnings are issued when comparing REAL or COMPLEX 9185 types for equality and inequality; consider replacing a == b by 9186 abs(a-b) < eps with a suitable eps. -Wcompare-reals is enabled by 9187 -Wextra. 9188 * The [22]-Wtarget-lifetime command-line option has been added 9189 (enabled with -Wall), which warns if the pointer in a pointer 9190 assignment might outlive its target. 9191 * Reading floating point numbers which use "q" for the exponential 9192 (such as 4.0q0) is now supported as vendor extension for better 9193 compatibility with old data files. It is strongly recommended to 9194 use for I/O the equivalent but standard conforming "e" (such as 9195 4.0e0). 9196 (For Fortran source code, consider replacing the "q" in 9197 floating-point literals by a kind parameter (e.g. 4.0e0_qp with a 9198 suitable qp). Note that - in Fortran source code - replacing "q" by 9199 a simple "e" is not equivalent.) 9200 * The GFORTRAN_TMPDIR environment variable for specifying a 9201 non-default directory for files opened with STATUS="SCRATCH", is 9202 not used anymore. Instead gfortran checks the POSIX/GNU standard 9203 TMPDIR environment variable. If TMPDIR is not defined, gfortran 9204 falls back to other methods to determine the directory for 9205 temporary files as documented in the [23]user manual. 9206 * [24]Fortran 2003: 9207 + Support for unlimited polymorphic variables (CLASS(*)) has 9208 been added. Nonconstant character lengths are not yet 9209 supported. 9210 * [25]TS 29113: 9211 + Assumed types (TYPE(*)) are now supported. 9212 + Experimental support for assumed-rank arrays (dimension(..)) 9213 has been added. Note that currently gfortran's own array 9214 descriptor is used, which is different from the one defined in 9215 TS29113, see [26]gfortran's header file or use the [27]Chasm 9216 Language Interoperability Tools. 9217 9218 Go 9219 9220 * GCC 4.8.2 provides a complete implementation of the Go 1.1.2 9221 release. 9222 * GCC 4.8.0 and 4.8.1 implement a preliminary version of the Go 1.1 9223 release. The library support is not quite complete. 9224 * Go has been tested on GNU/Linux and Solaris platforms for various 9225 processors including x86, x86_64, PowerPC, SPARC, and Alpha. It may 9226 work on other platforms as well. 9227 9228 New Targets and Target Specific Improvements 9229 9230 AArch64 9231 9232 * A new port has been added to support AArch64, the new 64-bit 9233 architecture from ARM. Note that this is a separate port from the 9234 existing 32-bit ARM port. 9235 * The port provides initial support for the Cortex-A53 and the 9236 Cortex-A57 processors with the command line options 9237 -mcpu=cortex-a53 and -mcpu=cortex-a57. 9238 * As of GCC 4.8.4 a workaround for the ARM Cortex-A53 erratum 835769 9239 has been added and can be enabled by giving the 9240 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 9241 default by configuring GCC with the --enable-fix-cortex-a53-835769 9242 option. 9243 9244 ARM 9245 9246 * Initial support has been added for the AArch32 extensions defined 9247 in the ARMv8 architecture. 9248 * Code generation improvements for the Cortex-A7 and Cortex-A15 CPUs. 9249 * A new option, -mcpu=marvell-pj4, has been added to generate code 9250 for the Marvell PJ4 processor. 9251 * The compiler can now automatically generate the VFMA, VFMS, REVSH 9252 and REV16 instructions. 9253 * A new vectorizer cost model for Advanced SIMD configurations to 9254 improve the auto-vectorization strategies used. 9255 * The scheduler now takes into account the number of live registers 9256 to reduce the amount of spilling that can occur. This should 9257 improve code performance in large functions. The limit can be 9258 removed by using the option -fno-sched-pressure. 9259 * Improvements have been made to the Marvell iWMMX code generation 9260 and support for the iWMMX2 SIMD unit has been added. The option 9261 -mcpu=iwmmxt2 can be used to enable code generation for the latter. 9262 * A number of code generation improvements for Thumb2 to reduce code 9263 size when compiling for the M-profile processors. 9264 * The RTEMS (arm-rtems) port has been updated to use the EABI. 9265 * Code generation support for the old FPA and Maverick floating-point 9266 architectures has been removed. Ports that previously relied on 9267 these features have also been removed. This includes the targets: 9268 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 9269 + arm*-*-elf (use arm*-*-eabi) 9270 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 9271 + arm*-*-ecos-elf (no alternative) 9272 + arm*-*-freebsd (no alternative) 9273 + arm*-wince-pe* (no alternative). 9274 9275 AVR 9276 9277 * Support for the "Embedded C" fixed-point has been added. For 9278 details, see the [28]GCC wiki and the [29]user manual. The support 9279 is not complete. 9280 * A new print modifier %r for register operands in inline assembler 9281 is supported. It will print the raw register number without the 9282 register prefix 'r': 9283 /* Return the most significant byte of 'val', a 64-bit value. */ 9284 9285 unsigned char msb (long long val) 9286 { 9287 unsigned char c; 9288 __asm__ ("mov %0, %r1+7" : "=r" (c) : "r" (val)); 9289 return c; 9290 } 9291 The inline assembler in this example will generate code like 9292 mov r24, 8+7 9293 provided c is allocated to R24 and val is allocated to R8...R15. 9294 This works because the GNU assembler accepts plain register numbers 9295 without register prefix. 9296 * Static initializers with 3-byte symbols are supported now: 9297 extern const __memx char foo; 9298 const __memx void *pfoo = &foo; 9299 This requires at least Binutils 2.23. 9300 9301 IA-32/x86-64 9302 9303 * Allow -mpreferred-stack-boundary=3 for the x86-64 architecture with 9304 SSE extensions disabled. Since the x86-64 ABI requires 16 byte 9305 stack alignment, this is ABI incompatible and intended to be used 9306 in controlled environments where stack space is an important 9307 limitation. This option will lead to wrong code when functions 9308 compiled with 16 byte stack alignment (such as functions from a 9309 standard library) are called with misaligned stack. In this case, 9310 SSE instructions may lead to misaligned memory access traps. In 9311 addition, variable arguments will be handled incorrectly for 16 9312 byte aligned objects (including x87 long double and __int128), 9313 leading to wrong results. You must build all modules with 9314 -mpreferred-stack-boundary=3, including any libraries. This 9315 includes the system libraries and startup modules. 9316 * Support for the new Intel processor codename Broadwell with RDSEED, 9317 ADCX, ADOX, PREFETCHW is available through -madx, -mprfchw, 9318 -mrdseed command-line options. 9319 * Support for the Intel RTM and HLE intrinsics, built-in functions 9320 and code generation is available via -mrtm and -mhle. 9321 * Support for the Intel FXSR, XSAVE and XSAVEOPT instruction sets. 9322 Intrinsics and built-in functions are available via -mfxsr, -mxsave 9323 and -mxsaveopt respectively. 9324 * New -maddress-mode=[short|long] options for x32. 9325 -maddress-mode=short overrides default 64-bit addresses to 32-bit 9326 by emitting the 0x67 address-size override prefix. This is the 9327 default address mode for x32. 9328 * New built-in functions to detect run-time CPU type and ISA: 9329 + A built-in function __builtin_cpu_is has been added to detect 9330 if the run-time CPU is of a particular type. It returns a 9331 positive integer on a match and zero otherwise. It accepts one 9332 string literal argument, the CPU name. For example, 9333 __builtin_cpu_is("westmere") returns a positive integer if the 9334 run-time CPU is an Intel Core i7 Westmere processor. Please 9335 refer to the [30]user manual for the list of valid CPU names 9336 recognized. 9337 + A built-in function __builtin_cpu_supports has been added to 9338 detect if the run-time CPU supports a particular ISA feature. 9339 It returns a positive integer on a match and zero otherwise. 9340 It accepts one string literal argument, the ISA feature. For 9341 example, __builtin_cpu_supports("ssse3") returns a positive 9342 integer if the run-time CPU supports SSSE3 instructions. 9343 Please refer to the [31]user manual for the list of valid ISA 9344 names recognized. 9345 Caveat: If these built-in functions are called before any static 9346 constructors are invoked, like during IFUNC initialization, then 9347 the CPU detection initialization must be explicitly run using this 9348 newly provided built-in function, __builtin_cpu_init. The 9349 initialization needs to be done only once. For example, this is how 9350 the invocation would look like inside an IFUNC initializer: 9351 static void (*some_ifunc_resolver(void))(void) 9352 { 9353 __builtin_cpu_init(); 9354 if (__builtin_cpu_is("amdfam10h") ... 9355 if (__builtin_cpu_supports("popcnt") ... 9356 } 9357 9358 * Function Multiversioning Support with G++: 9359 It is now possible to create multiple function versions each 9360 targeting a specific processor and/or ISA. Function versions have 9361 the same signature but different target attributes. For example, 9362 here is a program with function versions: 9363 __attribute__ ((target ("default"))) 9364 int foo(void) 9365 { 9366 return 1; 9367 } 9368 9369 __attribute__ ((target ("sse4.2"))) 9370 int foo(void) 9371 { 9372 return 2; 9373 } 9374 9375 int main (void) 9376 { 9377 int (*p) = &foo; 9378 assert ((*p)() == foo()); 9379 return 0; 9380 } 9381 9382 Please refer to this [32]wiki for more information. 9383 * The x86 back end has been improved to allow option -fschedule-insns 9384 to work reliably. This option can be used to schedule instructions 9385 better and leads to improved performace in certain cases. 9386 * Windows MinGW-w64 targets (*-w64-mingw*) require at least r5437 9387 from the Mingw-w64 trunk. 9388 * Support for new AMD family 15h processors (Steamroller core) is now 9389 available through the -march=bdver3 and -mtune=bdver3 options. 9390 * Support for new AMD family 16h processors (Jaguar core) is now 9391 available through the -march=btver2 and -mtune=btver2 options. 9392 9393 FRV 9394 9395 * This target now supports the -fstack-usage command-line option. 9396 9397 MIPS 9398 9399 * GCC can now generate code specifically for the R4700, Broadcom XLP 9400 and MIPS 34kn processors. The associated -march options are 9401 -march=r4700, -march=xlp and -march=34kn respectively. 9402 * GCC now generates better DSP code for MIPS 74k cores thanks to 9403 further scheduling optimizations. 9404 * The MIPS port now supports the -fstack-check option. 9405 * GCC now passes the -mmcu and -mno-mcu options to the assembler. 9406 * Previous versions of GCC would silently accept -fpic and -fPIC for 9407 -mno-abicalls targets like mips*-elf. This combination was not 9408 intended or supported, and did not generate position-independent 9409 code. GCC 4.8 now reports an error when this combination is used. 9410 9411 PowerPC / PowerPC64 / RS6000 9412 9413 * SVR4 configurations (GNU/Linux, FreeBSD, NetBSD) no longer save, 9414 restore or update the VRSAVE register by default. The respective 9415 operating systems manage the VRSAVE register directly. 9416 * Large TOC support has been added for AIX through the command line 9417 option -mcmodel=large. 9418 * Native Thread-Local Storage support has been added for AIX. 9419 * VMX (Altivec) and VSX instruction sets now are enabled implicitly 9420 when targetting processors that support those hardware features on 9421 AIX 6.1 and above. 9422 9423 RX 9424 9425 * This target will now issue a warning message whenever multiple fast 9426 interrupt handlers are found in the same compilation unit. This 9427 feature can be turned off by the new 9428 -mno-warn-multiple-fast-interrupts command-line option. 9429 9430 S/390, System z 9431 9432 * Support for the IBM zEnterprise zEC12 processor has been added. 9433 When using the -march=zEC12 option, the compiler will generate code 9434 making use of the following new instructions: 9435 + load and trap instructions 9436 + 2 new compare and trap instructions 9437 + rotate and insert selected bits - without CC clobber 9438 The -mtune=zEC12 option enables zEC12 specific instruction 9439 scheduling without making use of new instructions. 9440 * Register pressure sensitive instruction scheduling is enabled by 9441 default. 9442 * The ifunc function attribute is enabled by default. 9443 * memcpy and memcmp invokations on big memory chunks or with run time 9444 lengths are not generated inline anymore when tuning for z10 or 9445 higher. The purpose is to make use of the IFUNC optimized versions 9446 in Glibc. 9447 9448 SH 9449 9450 * The default alignment settings have been reduced to be less 9451 aggressive. This results in more compact code for optimization 9452 levels other than -Os. 9453 * Improved support for the __atomic built-in functions: 9454 + A new option -matomic-model=model selects the model for the 9455 generated atomic sequences. The following models are 9456 supported: 9457 9458 soft-gusa 9459 Software gUSA sequences (SH3* and SH4* only). On 9460 SH4A targets this will now also partially utilize 9461 the movco.l and movli.l instructions. This is the 9462 default when the target is sh3*-*-linux* or 9463 sh4*-*-linux*. 9464 9465 hard-llcs 9466 Hardware movco.l / movli.l sequences (SH4A only). 9467 9468 soft-tcb 9469 Software thread control block sequences. 9470 9471 soft-imask 9472 Software interrupt flipping sequences (privileged 9473 mode only). This is the default when the target is 9474 sh1*-*-linux* or sh2*-*-linux*. 9475 9476 none 9477 Generates function calls to the respective __atomic 9478 built-in functions. This is the default for SH64 9479 targets or when the target is not sh*-*-linux*. 9480 9481 + The option -msoft-atomic has been deprecated. It is now an 9482 alias for -matomic-model=soft-gusa. 9483 + A new option -mtas makes the compiler generate the tas.b 9484 instruction for the __atomic_test_and_set built-in function 9485 regardless of the selected atomic model. 9486 + The __sync functions in libgcc now reflect the selected atomic 9487 model when building the toolchain. 9488 * Added support for the mov.b and mov.w instructions with 9489 displacement addressing. 9490 * Added support for the SH2A instructions movu.b and movu.w. 9491 * Various improvements to code generated for integer arithmetic. 9492 * Improvements to conditional branches and code that involves the T 9493 bit. A new option -mzdcbranch tells the compiler to favor 9494 zero-displacement branches. This is enabled by default for SH4* 9495 targets. 9496 * The pref instruction will now be emitted by the __builtin_prefetch 9497 built-in function for SH3* targets. 9498 * The fmac instruction will now be emitted by the fmaf standard 9499 function and the __builtin_fmaf built-in function. 9500 * The -mfused-madd option has been deprecated in favor of the 9501 machine-independent -ffp-contract option. Notice that the fmac 9502 instruction will now be generated by default for expressions like a 9503 * b + c. This is due to the compiler default setting 9504 -ffp-contract=fast. 9505 * Added new options -mfsrra and -mfsca to allow the compiler using 9506 the fsrra and fsca instructions on targets other than SH4A (where 9507 they are already enabled by default). 9508 * Added support for the __builtin_bswap32 built-in function. It is 9509 now expanded as a sequence of swap.b and swap.w instructions 9510 instead of a library function call. 9511 * The behavior of the -mieee option has been fixed and the negative 9512 form -mno-ieee has been added to control the IEEE conformance of 9513 floating point comparisons. By default -mieee is now enabled and 9514 the option -ffinite-math-only implicitly sets -mno-ieee. 9515 * Added support for the built-in functions __builtin_thread_pointer 9516 and __builtin_set_thread_pointer. This assumes that GBR is used to 9517 hold the thread pointer of the current thread. Memory loads and 9518 stores relative to the address returned by __builtin_thread_pointer 9519 will now also utilize GBR based displacement address modes. 9520 * The -mdiv= option for targets other than SHmedia has been fixed and 9521 documented. 9522 9523 SPARC 9524 9525 * Added optimized instruction scheduling for Niagara4. 9526 9527 TILE-Gx 9528 9529 * Added support for the -mcmodel=MODEL command-line option. The 9530 models supported are small and large. 9531 9532 V850 9533 9534 * This target now supports the E3V5 architecture via the use of the 9535 new -mv850e3v5 command-line option. It also has experimental 9536 support for the e3v5 LOOP instruction which can be enabled via the 9537 new -mloop command-line option. 9538 9539 XStormy16 9540 9541 * This target now supports the -fstack-usage command-line option. 9542 9543 Operating Systems 9544 9545 OpenBSD 9546 9547 * Support for OpenBSD/amd64 (x86_64-*-openbsd*) has been added and 9548 support for OpenBSD/i386 (i386-*-openbsd*) has been rejuvenated. 9549 9550 Windows (Cygwin) 9551 9552 * Executables are now linked against shared libgcc by default. The 9553 previous default was to link statically, which can still be done by 9554 explicitly specifying -static or static-libgcc on the command line. 9555 However it is strongly advised against, as it will cause problems 9556 for any application that makes use of DLLs compiled by GCC. It 9557 should be alright for a monolithic stand-alone application that 9558 only links against the Windows DLLs, but offers little or no 9559 benefit. 9560 9561 GCC 4.8.1 9562 9563 This is the [33]list of problem reports (PRs) from GCC's bug tracking 9564 system that are known to be fixed in the 4.8.1 release. This list might 9565 not be complete (that is, it is possible that some PRs that have been 9566 fixed are not listed here). 9567 9568 The C++11 <chrono> std::chrono::system_clock and 9569 std::chrono::steady_clock classes have changed ABI in GCC 4.8.1, they 9570 both are now separate (never typedefs of each other), both use 9571 std::chrono::nanoseconds resolution, on most GNU/Linux configurations 9572 std::chrono::steady_clock is now finally monotonic, and both classes 9573 are mangled differently than in the previous GCC releases. 9574 std::chrono::system_clock::now() with std::chrono::microseconds resp. 9575 std::chrono::seconds resolution is still exported for backwards 9576 compatibility with default configured libstdc++. Note that libstdc++ 9577 configured with --enable-libstdcxx-time= used to be ABI incompatible 9578 with default configured libstdc++ for those two classes and no ABI 9579 compatibility can be offered for those configurations, so any C++11 9580 code that uses those classes and has been compiled and linked against 9581 libstdc++ configured with the non-default --enable-libstdcxx-time= 9582 configuration option needs to be recompiled. 9583 9584 GCC 4.8.2 9585 9586 This is the [34]list of problem reports (PRs) from GCC's bug tracking 9587 system that are known to be fixed in the 4.8.2 release. This list might 9588 not be complete (that is, it is possible that some PRs that have been 9589 fixed are not listed here). 9590 9591 GCC 4.8.3 9592 9593 This is the [35]list of problem reports (PRs) from GCC's bug tracking 9594 system that are known to be fixed in the 4.8.3 release. This list might 9595 not be complete (that is, it is possible that some PRs that have been 9596 fixed are not listed here). 9597 9598 Support for the new powerpc64le-linux platform has been added. It 9599 defaults to generating code that conforms to the ELFV2 ABI. 9600 9601 GCC 4.8.4 9602 9603 This is the [36]list of problem reports (PRs) from GCC's bug tracking 9604 system that are known to be fixed in the 4.8.4 release. This list might 9605 not be complete (that is, it is possible that some PRs that have been 9606 fixed are not listed here). 9607 9608 GCC 4.8.5 9609 9610 This is the [37]list of problem reports (PRs) from GCC's bug tracking 9611 system that are known to be fixed in the 4.8.5 release. This list might 9612 not be complete (that is, it is possible that some PRs that have been 9613 fixed are not listed here). 9614 9615 9616 For questions related to the use of GCC, please consult these web 9617 pages and the [38]GCC manuals. If that fails, the 9618 [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9619 web pages and the development of GCC are welcome on our developer 9620 list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public 9621 archives. 9622 9623 Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and 9624 distribution of this entire article is permitted in any medium, 9625 provided this notice is preserved. 9626 9627 These pages are [43]maintained by the GCC team. Last modified 9628 2022-11-05. 9629 9630 References 9631 9632 1. https://gcc.gnu.org/wiki/cxx-conversion 9633 2. ftp://gcc.gnu.org/pub/gcc/infrastructure/ 9634 3. http://www.nongnu.org/avr-libc/ 9635 4. https://gcc.gnu.org/PR54461 9636 5. https://gcc.gnu.org/gcc-4.8/porting_to.html 9637 6. https://github.com/google/sanitizers 9638 7. https://code.google.com/archive/p/data-race-test/wikis/ThreadSanitizer.wiki 9639 8. https://lkml.org/lkml/2006/11/28/239 9640 9. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 9641 10. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 9642 11. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 9643 12. https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3276.pdf 9644 13. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 9645 14. https://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3386.html 9646 15. http://gcc.gnu.org/projects/cxx1y.html 9647 16. https://gcc.gnu.org/onlinedocs/gcc-4.8.4/libstdc++/manual/manual/status.html#status.iso.2011 9648 17. https://gcc.gnu.org/onlinedocs/gfortran/BACKTRACE.html 9649 18. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 9650 19. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 9651 20. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 9652 21. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 9653 22. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 9654 23. https://gcc.gnu.org/onlinedocs/gfortran/TMPDIR.html 9655 24. https://gcc.gnu.org/wiki/Fortran2003Status 9656 25. https://gcc.gnu.org/wiki/TS29113Status 9657 26. https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libgfortran/libgfortran.h 9658 27. https://chasm-interop.sourceforge.net/ 9659 28. https://gcc.gnu.org/wiki/avr-gcc#Fixed-Point_Support 9660 29. https://gcc.gnu.org/onlinedocs/gcc/Fixed-Point.html 9661 30. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 9662 31. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 9663 32. https://gcc.gnu.org/wiki/FunctionMultiVersioning 9664 33. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.1 9665 34. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.2 9666 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.3 9667 36. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.4 9668 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.5 9669 38. https://gcc.gnu.org/onlinedocs/ 9670 39. mailto:gcc-help (a] gcc.gnu.org 9671 40. mailto:gcc (a] gcc.gnu.org 9672 41. https://gcc.gnu.org/lists.html 9673 42. https://www.fsf.org/ 9674 43. https://gcc.gnu.org/about.html 9675 ====================================================================== 9676 http://gcc.gnu.org/gcc-4.7/index.html 9677 9678 GCC 4.7 Release Series 9679 9680 (This release series is no longer supported.) 9681 9682 June 12, 2014 9683 9684 The [1]GNU project and the GCC developers are pleased to announce the 9685 release of GCC 4.7.4. 9686 9687 This release is a bug-fix release, containing fixes for regressions in 9688 GCC 4.7.3 relative to previous releases of GCC. 9689 9690 Release History 9691 9692 GCC 4.7.4 9693 June 12, 2014 ([2]changes, [3]documentation) 9694 9695 GCC 4.7.3 9696 April 11, 2013 ([4]changes, [5]documentation) 9697 9698 GCC 4.7.2 9699 September 20, 2012 ([6]changes, [7]documentation) 9700 9701 GCC 4.7.1 9702 June 14, 2012 ([8]changes, [9]documentation) 9703 9704 GCC 4.7.0 9705 March 22, 2012 ([10]changes, [11]documentation) 9706 9707 References and Acknowledgements 9708 9709 GCC used to stand for the GNU C Compiler, but since the compiler 9710 supports several other languages aside from C, it now stands for the 9711 GNU Compiler Collection. 9712 9713 A list of [12]successful builds is updated as new information becomes 9714 available. 9715 9716 The GCC developers would like to thank the numerous people that have 9717 contributed new features, improvements, bug fixes, and other changes as 9718 well as test results to GCC. This [13]amazing group of volunteers is 9719 what makes GCC successful. 9720 9721 For additional information about GCC please refer to the [14]GCC 9722 project web site or contact the [15]GCC development mailing list. 9723 9724 To obtain GCC please use [16]our mirror sites or [17]our version 9725 control system. 9726 9727 9728 For questions related to the use of GCC, please consult these web 9729 pages and the [18]GCC manuals. If that fails, the 9730 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9731 web pages and the development of GCC are welcome on our developer 9732 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 9733 archives. 9734 9735 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 9736 distribution of this entire article is permitted in any medium, 9737 provided this notice is preserved. 9738 9739 These pages are [23]maintained by the GCC team. Last modified 9740 2022-10-26. 9741 9742 References 9743 9744 1. http://www.gnu.org/ 9745 2. http://gcc.gnu.org/gcc-4.7/changes.html 9746 3. https://gcc.gnu.org/onlinedocs/4.7.4/ 9747 4. http://gcc.gnu.org/gcc-4.7/changes.html 9748 5. https://gcc.gnu.org/onlinedocs/4.7.3/ 9749 6. http://gcc.gnu.org/gcc-4.7/changes.html 9750 7. https://gcc.gnu.org/onlinedocs/4.7.2/ 9751 8. http://gcc.gnu.org/gcc-4.7/changes.html 9752 9. https://gcc.gnu.org/onlinedocs/4.7.1/ 9753 10. http://gcc.gnu.org/gcc-4.7/changes.html 9754 11. https://gcc.gnu.org/onlinedocs/4.7.0/ 9755 12. http://gcc.gnu.org/gcc-4.7/buildstat.html 9756 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 9757 14. http://gcc.gnu.org/index.html 9758 15. mailto:gcc (a] gcc.gnu.org 9759 16. http://gcc.gnu.org/mirrors.html 9760 17. http://gcc.gnu.org/git.html 9761 18. https://gcc.gnu.org/onlinedocs/ 9762 19. mailto:gcc-help (a] gcc.gnu.org 9763 20. mailto:gcc (a] gcc.gnu.org 9764 21. https://gcc.gnu.org/lists.html 9765 22. https://www.fsf.org/ 9766 23. https://gcc.gnu.org/about.html 9767 ====================================================================== 9768 http://gcc.gnu.org/gcc-4.7/changes.html 9769 9770 GCC 4.7 Release Series 9771 Changes, New Features, and Fixes 9772 9773 Caveats 9774 9775 * The -fconserve-space flag has been deprecated. The flag had no 9776 effect for most targets: only targets without a global .bss section 9777 and without support for switchable sections. Furthermore, the flag 9778 only had an effect for G++, where it could result in wrong 9779 semantics (please refer to the GCC manual for further details). The 9780 flag will be removed in GCC 4.8 9781 * Support for a number of older systems and recently unmaintained or 9782 untested target ports of GCC has been declared obsolete in GCC 4.7. 9783 Unless there is activity to revive them, the next release of GCC 9784 will have their sources permanently removed. 9785 All GCC ports for the following processor architectures have been 9786 declared obsolete: 9787 + picoChip (picochip-*) 9788 The following ports for individual systems on particular 9789 architectures have been obsoleted: 9790 + IRIX 6.5 (mips-sgi-irix6.5) 9791 + MIPS OpenBSD (mips*-*-openbsd*) 9792 + Solaris 8 (*-*-solaris2.8). Details can be found in the 9793 [1]announcement. 9794 + Tru64 UNIX V5.1 (alpha*-dec-osf5.1*) 9795 * On ARM, when compiling for ARMv6 (but not ARMv6-M), ARMv7-A, 9796 ARMv7-R, or ARMv7-M, the new option -munaligned-access is active by 9797 default, which for some sources generates code that accesses memory 9798 on unaligned addresses. This requires the kernel of those systems 9799 to enable such accesses (controlled by CP15 register c1, refer to 9800 ARM documentation). Alternatively, or for compatibility with 9801 kernels where unaligned accesses are not supported, all code has to 9802 be compiled with -mno-unaligned-access. Upstream Linux kernel 9803 releases have automatically and unconditionally supported unaligned 9804 accesses as emitted by GCC due to this option being active since 9805 version 2.6.28. 9806 * Support on ARM for the legacy floating-point accelerator (FPA) and 9807 the mixed-endian floating-point format that it used has been 9808 obsoleted. The ports that still use this format have been obsoleted 9809 as well. Many legacy ARM ports already provide an alternative that 9810 uses the VFP floating-point format. The obsolete ports will be 9811 deleted in the next release. 9812 The obsolete ports with alternatives are: 9813 + arm*-*-rtems (use arm*-*-rtemseabi) 9814 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 9815 + arm*-*-elf (use arm*-*-eabi) 9816 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 9817 Note, however, that these alternatives are not binary compatible 9818 with their legacy counterparts (although some can support running 9819 legacy applications). 9820 The obsolete ports that currently lack a modern alternative are: 9821 + arm*-*-ecos-elf 9822 + arm*-*-freebsd 9823 + arm*-wince-pe* 9824 New ports that support more recent versions of the architecture are 9825 welcome. 9826 * Support for the Maverick co-processor on ARM has been obsoleted. 9827 Code to support it will be deleted in the next release. 9828 * Support has been removed for Unix International threads on Solaris 9829 2, so the --enable-threads=solaris configure option and the 9830 -threads compiler option don't work any longer. 9831 * Support has been removed for the Solaris BSD Compatibility Package, 9832 which lives in /usr/ucbinclude and /usr/ucblib. It has been removed 9833 from Solaris 11, and was only intended as a migration aid from 9834 SunOS 4 to SunOS 5. The -compat-bsd compiler option is not 9835 recognized any longer. 9836 * The AVR port's libgcc has been improved and its multilib structure 9837 has been enhanced. As a result, all objects contributing to an 9838 application must either be compiled with GCC versions up to 4.6.x 9839 or with GCC versions 4.7.1 or later. If the compiler is used with 9840 AVR Libc, you need a version that supports the new layout, i.e. 9841 implements [2]#35407. 9842 * The AVR port's -mshort-calls command-line option has been 9843 deprecated. It will be removed in the GCC 4.8 release. See -mrelax 9844 for a replacement. 9845 * The AVR port only references startup code that clears .bss and the 9846 common section resp. initializes the .data and .rodata section 9847 provided respective sections (or subsections thereof) are not 9848 empty, see [3]PR18145. Applications that put all static storage 9849 objects into non-standard sections and / or define all static 9850 storage objects in assembler modules, must reference __do_clear_bss 9851 resp. __do_copy_data by hand or undefine the symbol(s) by means of 9852 -Wl,-u,__do_clear_bss resp. -Wl,-u,__do_copy_data. 9853 * The ARM port's -mwords-little-endian option has been deprecated. It 9854 will be removed in a future release. 9855 * Support has been removed for the NetWare x86 configuration 9856 obsoleted in GCC 4.6. 9857 * It is no longer possible to use the "l" constraint in MIPS16 asm 9858 statements. 9859 * GCC versions 4.7.0 and 4.7.1 had changes to the C++ standard 9860 library which affected the ABI in C++11 mode: a data member was 9861 added to std::list changing its size and altering the definitions 9862 of some member functions, and std::pair's move constructor was 9863 non-trivial which altered the calling convention for functions with 9864 std::pair arguments or return types. The ABI incompatibilities have 9865 been fixed for GCC version 4.7.2 but as a result C++11 code 9866 compiled with GCC 4.7.0 or 4.7.1 may be incompatible with C++11 9867 code compiled with different GCC versions and with C++98/C++03 code 9868 compiled with any version. 9869 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 9870 rules for the layout of vectors that could lead to wrong code being 9871 generated. Vectors larger than 8 bytes in size are now by default 9872 aligned to an 8-byte boundary. This is an ABI change: code that 9873 makes explicit use of vector types may be incompatible with binary 9874 objects built with older versions of GCC. Auto-vectorized code is 9875 not affected by this change. (This change affects GCC versions 9876 4.7.2 and later.) 9877 * More information on porting to GCC 4.7 from previous versions of 9878 GCC can be found in the [4]porting guide for this release. 9879 9880 General Optimizer Improvements 9881 9882 * Support for a new parameter --param case-values-threshold=n was 9883 added to allow users to control the cutoff between doing switch 9884 statements as a series of if statements and using a jump table. 9885 * Link-time optimization (LTO) improvements: 9886 + Improved scalability and reduced memory usage. Link time 9887 optimization of Firefox now requires 3GB of RAM on a 64-bit 9888 system, while over 8GB was needed previously. Linking time has 9889 been improved, too. The serial stage of linking Firefox has 9890 been sped up by about a factor of 10. 9891 + Reduced size of object files and temporary storage used during 9892 linking. 9893 + Streaming performance (both outbound and inbound) has been 9894 improved. 9895 + ld -r is now supported with LTO. 9896 + Several bug fixes, especially in symbol table handling and 9897 merging. 9898 * Interprocedural optimization improvements: 9899 + Heuristics now take into account that after inlining code will 9900 be optimized out because of known values (or properties) of 9901 function parameters. For example: 9902 void foo(int a) 9903 { 9904 if (a > 10) 9905 ... huge code ... 9906 } 9907 void bar (void) 9908 { 9909 foo (0); 9910 } 9911 9912 The call of foo will be inlined into bar even when optimizing 9913 for code size. Constructs based on __builtin_constant_p are 9914 now understood by the inliner and code size estimates are 9915 evaluated a lot more realistically. 9916 + The representation of C++ virtual thunks and aliases (both 9917 implicit and defined via the alias attribute) has been 9918 re-engineered. Aliases no longer pose optimization barriers 9919 and calls to an alias can be inlined and otherwise optimized. 9920 + The inter-procedural constant propagation pass has been 9921 rewritten. It now performs generic function specialization. 9922 For example when compiling the following: 9923 void foo(bool flag) 9924 { 9925 if (flag) 9926 ... do something ... 9927 else 9928 ... do something else ... 9929 } 9930 void bar (void) 9931 { 9932 foo (false); 9933 foo (true); 9934 foo (false); 9935 foo (true); 9936 foo (false); 9937 foo (true); 9938 } 9939 9940 GCC will now produce two copies of foo. One with flag being 9941 true, while other with flag being false. This leads to 9942 performance improvements previously possible only by inlining 9943 all calls. Cloning causes a lot less code size growth. 9944 * A string length optimization pass has been added. It attempts to 9945 track string lengths and optimize various standard C string 9946 functions like strlen, strchr, strcpy, strcat, stpcpy and their 9947 _FORTIFY_SOURCE counterparts into faster alternatives. This pass is 9948 enabled by default at -O2 or above, unless optimizing for size, and 9949 can be disabled by the -fno-optimize-strlen option. The pass can 9950 e.g. optimize 9951 char *bar (const char *a) 9952 { 9953 size_t l = strlen (a) + 2; 9954 char *p = malloc (l); if (p == NULL) return p; 9955 strcpy (p, a); strcat (p, "/"); return p; 9956 } 9957 9958 into: 9959 char *bar (const char *a) 9960 { 9961 size_t tmp = strlen (a); 9962 char *p = malloc (tmp + 2); if (p == NULL) return p; 9963 memcpy (p, a, tmp); memcpy (p + tmp, "/", 2); return p; 9964 } 9965 9966 or for hosted compilations where stpcpy is available in the runtime 9967 and headers provide its prototype, e.g. 9968 void foo (char *a, const char *b, const char *c, const char *d) 9969 { 9970 strcpy (a, b); strcat (a, c); strcat (a, d); 9971 } 9972 9973 can be optimized into: 9974 void foo (char *a, const char *b, const char *c, const char *d) 9975 { 9976 strcpy (stpcpy (stpcpy (a, b), c), d); 9977 } 9978 9979 New Languages and Language specific improvements 9980 9981 * Version 3.1 of the OpenMP specification is now supported for the C, 9982 C++, and Fortran compilers. 9983 9984 Ada 9985 9986 * The command-line option -feliminate-unused-debug-types has been 9987 re-enabled by default, as it is for the other languages, leading to 9988 a reduction in debug info size of 12.5% and more for relevant 9989 cases, as well as to a small compilation speedup. 9990 9991 C family 9992 9993 * A new built-in, __builtin_assume_aligned, has been added, through 9994 which the compiler can be hinted about pointer alignment and can 9995 use it to improve generated code. 9996 * A new warning option -Wunused-local-typedefs was added for C, C++, 9997 Objective-C and Objective-C++. This warning diagnoses typedefs 9998 locally defined in a function, and otherwise not used. 9999 * A new experimental command-line option -ftrack-macro-expansion was 10000 added for C, C++, Objective-C, Objective-C++ and Fortran. It allows 10001 the compiler to emit diagnostic about the current macro expansion 10002 stack when a compilation error occurs in a macro expansion. 10003 * Experimental support for transactional memory has been added. It 10004 includes support in the compiler, as well as a supporting runtime 10005 library called libitm. To compile code with transactional memory 10006 constructs, use the -fgnu-tm option. 10007 Support is currently available for Alpha, ARM, PowerPC, SH, SPARC, 10008 and 32-bit/64-bit x86 platforms. 10009 For more details on transactional memory see [5]the GCC WiKi. 10010 * Support for atomic operations specifying the C++11/C11 memory model 10011 has been added. These new __atomic routines replace the existing 10012 __sync built-in routines. 10013 Atomic support is also available for memory blocks. Lock-free 10014 instructions will be used if a memory block is the same size and 10015 alignment as a supported integer type. Atomic operations which do 10016 not have lock-free support are left as function calls. A set of 10017 library functions is available on the GCC atomic wiki in the 10018 "External Atomics Library" section. 10019 For more details on the memory models and features, see the 10020 [6]atomic wiki. 10021 * When a binary operation is performed on vector types and one of the 10022 operands is a uniform vector, it is possible to replace the vector 10023 with the generating element. For example: 10024 typedef int v4si __attribute__ ((vector_size (16))); 10025 v4si res, a = {1,2,3,4}; 10026 int x; 10027 10028 res = 2 + a; /* means {2,2,2,2} + a */ 10029 res = a - x; /* means a - {x,x,x,x} */ 10030 10031 C 10032 10033 * There is support for some more features from the C11 revision of 10034 the ISO C standard. GCC now accepts the options -std=c11 and 10035 -std=gnu11, in addition to the previous -std=c1x and -std=gnu1x. 10036 + Unicode strings (previously supported only with options such 10037 as -std=gnu11, now supported with -std=c11), and the 10038 predefined macros __STDC_UTF_16__ and __STDC_UTF_32__. 10039 + Nonreturning functions (_Noreturn and <stdnoreturn.h>). 10040 + Alignment support (_Alignas, _Alignof, max_align_t, 10041 <stdalign.h>). 10042 + A built-in function __builtin_complex is provided to support C 10043 library implementation of the CMPLX family of macros. 10044 10045 C++ 10046 10047 * G++ now accepts the -std=c++11, -std=gnu++11, and -Wc++11-compat 10048 options, which are equivalent to -std=c++0x, -std=gnu++0x, and 10049 -Wc++0x-compat, respectively. 10050 * G++ now implements [7]C++11 extended friend syntax: 10051 10052 template<class W> 10053 class Q 10054 { 10055 static const int I = 2; 10056 public: 10057 friend W; 10058 }; 10059 10060 struct B 10061 { 10062 int ar[Q<B>::I]; 10063 }; 10064 10065 * Thanks to Ville Voutilainen, G++ now implements [8]C++11 explicit 10066 override control. 10067 10068 struct B { 10069 virtual void f() const final; 10070 virtual void f(int); 10071 }; 10072 10073 struct D : B { 10074 void f() const; // error: D::f attempts to override final B::f 10075 void f(long) override; // error: doesn't override anything 10076 void f(int) override; // ok 10077 }; 10078 10079 struct E final { }; 10080 struct F: E { }; // error: deriving from final class 10081 10082 * G++ now implements [9]C++11 non-static data member initializers. 10083 10084 struct A { 10085 int i = 42; 10086 } a; // initializes a.i to 42 10087 10088 * Thanks to Ed Smith-Rowland, G++ now implements [10]C++11 10089 user-defined literals. 10090 10091 // Not actually a good approximation. :) 10092 constexpr long double operator"" _degrees (long double d) { return d * 0.0175; } 10093 long double pi = 180.0_degrees; 10094 10095 * G++ now implements [11]C++11 alias-declarations. 10096 10097 template <class T> using Ptr = T*; 10098 Ptr<int> ip; // decltype(ip) is int* 10099 10100 * Thanks to Ville Voutilainen and Pedro Lamaro, G++ now implements 10101 [12]C++11 delegating constructors. 10102 10103 struct A { 10104 A(int); 10105 A(): A(42) { } // delegate to the A(int) constructor 10106 }; 10107 10108 * G++ now fully implements C++11 atomic classes rather than just 10109 integer derived classes. 10110 10111 class POD { 10112 int a; 10113 int b; 10114 }; 10115 std::atomic<POD> my_atomic_POD; 10116 10117 * G++ now sets the predefined macro __cplusplus to the correct value, 10118 199711L for C++98/03, and 201103L for C++11. 10119 * G++ now correctly implements the two-phase lookup rules such that 10120 an unqualified name used in a template must have an appropriate 10121 declaration found either in scope at the point of definition of the 10122 template or by argument-dependent lookup at the point of 10123 instantiation. As a result, code that relies on a second 10124 unqualified lookup at the point of instantiation to find functions 10125 declared after the template or in dependent bases will be rejected. 10126 The compiler will suggest ways to fix affected code, and using the 10127 -fpermissive compiler flag will allow the code to compile with a 10128 warning. 10129 10130 template <class T> 10131 void f() { g(T()); } // error, g(int) not found by argument-dependent lookup 10132 void g(int) { } // fix by moving this declaration before the declaration of f 10133 10134 template <class T> 10135 struct A: T { 10136 // error, B::g(B) not found by argument-dependent lookup 10137 void f() { g(T()); } // fix by using this->g or A::g 10138 }; 10139 10140 struct B { void g(B); }; 10141 10142 int main() 10143 { 10144 f<int>(); 10145 A<B>().f(); 10146 } 10147 10148 * G++ now properly re-uses stack space allocated for temporary 10149 objects when their lifetime ends, which can significantly lower 10150 stack consumption for some C++ functions. As a result of this, some 10151 code with undefined behavior will now break: 10152 10153 const int &f(const int &i) { return i; } 10154 .... 10155 const int &x = f(1); 10156 const int &y = f(2); 10157 10158 Here, x refers to the temporary allocated to hold the 1 argument, 10159 which only lives until the end of the initialization; it 10160 immediately becomes a dangling reference. So the next statement 10161 re-uses the stack slot to hold the 2 argument, and users of x get 10162 that value instead. 10163 Note that this should not cause any change of behavior for 10164 temporaries of types with non-trivial destructors, as they are 10165 already destroyed at end of full-expression; the change is that now 10166 the storage is released as well. 10167 * A new command-line option -Wdelete-non-virtual-dtor has been added 10168 to warn when delete is used to destroy an instance of a class which 10169 has virtual functions and non-virtual destructor. It is unsafe to 10170 delete an instance of a derived class through a pointer to a base 10171 class if the base class does not have a virtual destructor. This 10172 warning is enabled by -Wall. 10173 * A new command-line option -Wzero-as-null-pointer-constant has been 10174 added to warn when a literal '0' is used as null pointer constant. 10175 It can be useful to facilitate the conversion to nullptr in C++11. 10176 * As per C++98, access-declarations are now deprecated by G++. 10177 Using-declarations are to be used instead. Furthermore, some 10178 efforts have been made to improve the support of class scope 10179 using-declarations. In particular, using-declarations referring to 10180 a dependent type now work as expected ([13]bug c++/14258). 10181 * The ELF symbol visibility of a template instantiation is now 10182 properly constrained by the visibility of its template arguments 10183 ([14]bug c++/35688). 10184 10185 Runtime Library (libstdc++) 10186 10187 * [15]Improved experimental support for the new ISO C++ standard, 10188 C++11, including: 10189 + using noexcept in most of the library; 10190 + implementations of pointer_traits, allocator_traits and 10191 scoped_allocator_adaptor; 10192 + uses-allocator construction for tuple; 10193 + vector meets the allocator-aware container requirements; 10194 + replacing monotonic_clock with steady_clock; 10195 + enabling the thread support library on most POSIX targets; 10196 + many small improvements to conform to the FDIS. 10197 * Added --enable-clocale=newlib configure option. 10198 * Debug Mode iterators for unordered associative containers. 10199 * Avoid polluting the global namespace and do not include <unistd.h>. 10200 10201 Fortran 10202 10203 * The compile flag [16]-fstack-arrays has been added, which causes 10204 all local arrays to be put on stack memory. For some programs this 10205 will improve the performance significantly. If your program uses 10206 very large local arrays, it is possible that you will have to 10207 extend your runtime limits for stack memory. 10208 * The [17]-Ofast flag now also implies [18]-fno-protect-parens and 10209 [19]-fstack-arrays. 10210 * Front-end optimizations can now be selected by the 10211 [20]-ffrontend-optimize option and deselected by the 10212 -fno-frontend-optimize option. 10213 * When front-end optimization removes a function call, 10214 [21]-Wfunction-elimination warns about that. 10215 * When performing front-end-optimization, the 10216 [22]-faggressive-function-elimination option allows the removal of 10217 duplicate function calls even for impure functions. 10218 * The flag [23]-Wreal-q-constant has been added, which warns if 10219 floating-point literals have been specified using q (such as 10220 1.0q0); the q marker is now supported as a vendor extension to 10221 denote quad precision (REAL(16) or, if not available, REAL(10)). 10222 Consider using a kind parameter (such as in 1.0_qp) instead, which 10223 can be obtained via [24]SELECTED_REAL_KIND. 10224 * The GFORTRAN_USE_STDERR environment variable has been removed. GNU 10225 Fortran now always prints error messages to standard error. If you 10226 wish to redirect standard error, please consult the manual for your 10227 OS, shell, batch environment etc. as appropriate. 10228 * The -fdump-core option and GFORTRAN_ERROR_DUMPCORE environment 10229 variable have been removed. When encountering a serious error, 10230 gfortran will now always abort the program. Whether a core dump is 10231 generated depends on the user environment settings; see the ulimit 10232 -c setting for POSIX shells, limit coredumpsize for C shells, and 10233 the [25]WER user-mode dumps settings on Windows. 10234 * The [26]-fbacktrace option is now enabled by default. When 10235 encountering a fatal error, gfortran will attempt to print a 10236 backtrace to standard error before aborting. It can be disabled 10237 with -fno-backtrace. Note: On POSIX targets with the addr2line 10238 utility from GNU binutils, GNU Fortran can print a backtrace with 10239 function name, file name, line number information in addition to 10240 the addresses; otherwise only the addresses are printed. 10241 * [27]Fortran 2003: 10242 + Generic interface names which have the same name as derived 10243 types are now supported, which allows to write constructor 10244 functions. Note that Fortran does not support static 10245 constructor functions; only default initialization or an 10246 explicit structure-constructor initialization are available. 10247 + [28]Polymorphic (class) arrays are now supported. 10248 * [29]Fortran 2008: 10249 + Support for the DO CONCURRENT construct has been added, which 10250 allows the user to specify that individual loop iterations 10251 have no interdependencies. 10252 + [30]Coarrays: Full single-image support except for polymorphic 10253 coarrays. Additionally, preliminary support for multiple 10254 images via an MPI-based [31]coarray communication library has 10255 been added. Note: The library version is not yet usable as 10256 remote coarray access is not yet possible. 10257 * [32]TS 29113: 10258 + New flag [33]-std=f2008ts permits programs that are expected 10259 to conform to the Fortran 2008 standard and the draft 10260 Technical Specification (TS) 29113 on Further Interoperability 10261 of Fortran with C. 10262 + The OPTIONAL attribute is now allowed for dummy arguments of 10263 BIND(C) procedures. 10264 + The RANK intrinsic has been added. 10265 + The implementation of the ASYNCHRONOUS attribute in GCC is 10266 compatible with the candidate draft of TS 29113 (since GCC 10267 4.6). 10268 10269 Go 10270 10271 * GCC 4.7 implements the [34]Go 1 language standard. The library 10272 support in 4.7.0 is not quite complete, due to release timing. 10273 Release 4.7.1 includes complete support for Go 1. The Go library is 10274 from the Go 1.0.1 release. 10275 * Go has been tested on GNU/Linux and Solaris platforms. It may work 10276 on other platforms as well. 10277 10278 New Targets and Target Specific Improvements 10279 10280 ARM 10281 10282 * GCC now supports the Cortex-A7 processor implementing the v7-a 10283 version of the architecture using the option -mcpu=cortex-a7. 10284 * The default vector size in auto-vectorization for NEON is now 128 10285 bits. If vectorization fails thusly, the vectorizer tries again 10286 with 64-bit vectors. 10287 * A new option -mvectorize-with-neon-double was added to allow users 10288 to change the vector size to 64 bits. 10289 10290 AVR 10291 10292 * GCC now supports the XMEGA architecture. This requires GNU binutils 10293 2.22 or later. 10294 * Support for the [35]named address spaces __flash, __flash1, ..., 10295 __flash5 and __memx has been added. These address spaces locate 10296 read-only data in flash memory and allow reading from flash memory 10297 by means of ordinary C code, i.e. without the need of (inline) 10298 assembler code: 10299 10300 const __flash int values[] = { 42, 31 }; 10301 10302 int add_values (const __flash int *p, int i) 10303 { 10304 return values[i] + *p; 10305 } 10306 10307 * Support has been added for the AVR-specific configure option 10308 --with-avrlibc=yes in order to arrange for better integration of 10309 [36]AVR-Libc. This configure option is supported in avr-gcc 4.7.2 10310 and newer and will only take effect in non-RTEMS configurations. If 10311 avr-gcc is configured for RTEMS, the option will be ignored which 10312 is the same as specifying --with-avrlibc=no. See [37]PR54461 for 10313 more technical details. 10314 * Support for AVR-specific [38]built-in functions has been added. 10315 * Support has been added for the signed and unsigned 24-bit scalar 10316 integer types __int24 and __uint24. 10317 * New command-line options -maccumulate-args, -mbranch-cost=cost and 10318 -mstrict-X were added to allow better fine-tuning of code 10319 optimization. 10320 * The command-line option -fdata-sections now also takes affect on 10321 the section names of variables with the progmem attribute. 10322 * A new inline assembler print modifier %i to print a RAM address as 10323 I/O address has been added: 10324 10325 #include <avr/io.h> /* Port Definitions from AVR-LibC */ 10326 10327 void set_portb (uint8_t value) 10328 { 10329 asm volatile ("out %i0, %1" :: "n" (&PORTB), "r" (value) : "memory"); 10330 } 10331 10332 The offset between an I/O address and the RAM address for that I/O 10333 location is device-specific. This offset is taken into account when 10334 printing a RAM address with the %i modifier so that the address is 10335 suitable to be used as operand in an I/O command. The address must 10336 be a constant integer known at compile time. 10337 * The inline assembler constraint "R" to represent integers in the 10338 range -6 ... 5 has been removed without replacement. 10339 * Many optimizations to: 10340 + 64-bit integer arithmetic 10341 + Widening multiplication 10342 + Integer division by a constant 10343 + Avoid constant reloading in multi-byte instructions. 10344 + Micro-optimizations for special instruction sequences. 10345 + Generic built-in functions like __builtin_ffs*, 10346 __builtin_clz*, etc. 10347 + If-else decision trees generated by switch instructions 10348 + Merging of data located in flash memory 10349 + New libgcc variants for devices with 8-bit wide stack pointer 10350 + ... 10351 * Better documentation: 10352 + Handling of EIND and indirect jumps on devices with more than 10353 128 KiB of program memory. 10354 + Handling of the RAMPD, RAMPX, RAMPY and RAMPZ special function 10355 registers. 10356 + Function attributes OS_main and OS_task. 10357 + AVR-specific built-in macros. 10358 10359 C6X 10360 10361 * Support has been added for the Texas Instruments C6X family of 10362 processors. 10363 10364 CR16 10365 10366 * Support has been added for National Semiconductor's CR16 10367 architecture. 10368 10369 Epiphany 10370 10371 * Support has been added for Adapteva's Epiphany architecture. 10372 10373 IA-32/x86-64 10374 10375 * Support for Intel AVX2 intrinsics, built-in functions and code 10376 generation is available via -mavx2. 10377 * Support for Intel BMI2 intrinsics, built-in functions and code 10378 generation is available via -mbmi2. 10379 * Implementation and automatic generation of __builtin_clz* using the 10380 lzcnt instruction is available via -mlzcnt. 10381 * Support for Intel FMA3 intrinsics and code generation is available 10382 via -mfma. 10383 * A new -mfsgsbase command-line option is available that makes GCC 10384 generate new segment register read/write instructions through 10385 dedicated built-ins. 10386 * Support for the new Intel rdrnd instruction is available via 10387 -mrdrnd. 10388 * Two additional AVX vector conversion instructions are available via 10389 -mf16c. 10390 * Support for new Intel processor codename IvyBridge with RDRND, 10391 FSGSBASE and F16C is available through -march=core-avx-i. 10392 * Support for the new Intel processor codename Haswell with AVX2, 10393 FMA, BMI, BMI2, LZCNT is available through -march=core-avx2. 10394 * Support for new AMD family 15h processors (Piledriver core) is now 10395 available through -march=bdver2 and -mtune=bdver2 options. 10396 * Support for [39]the x32 psABI is now available through the -mx32 10397 option. 10398 * Windows mingw targets are using the -mms-bitfields option by 10399 default. 10400 * Windows x86 targets are using the __thiscall calling convention for 10401 C++ class-member functions. 10402 * Support for the configure option --with-threads=posix for Windows 10403 mingw targets. 10404 10405 MIPS 10406 10407 * GCC now supports thread-local storage (TLS) for MIPS16. This 10408 requires GNU binutils 2.22 or later. 10409 * GCC can now generate code specifically for the Cavium Octeon+ and 10410 Octeon2 processors. The associated command-line options are 10411 -march=octeon+ and -march=octeon2 respectively. Both options 10412 require GNU binutils 2.22 or later. 10413 * GCC can now work around certain 24k errata, under the control of 10414 the command-line option -mfix-24k. These workarounds require GNU 10415 binutils 2.20 or later. 10416 * 32-bit MIPS GNU/Linux targets such as mips-linux-gnu can now build 10417 n32 and n64 multilibs. The result is effectively a 64-bit GNU/Linux 10418 toolchain that generates 32-bit code by default. Use the 10419 configure-time option --enable-targets=all to select these extra 10420 multilibs. 10421 * Passing -fno-delayed-branch now also stops the assembler from 10422 automatically filling delay slots. 10423 10424 PowerPC/PowerPC64 10425 10426 * Vectors of type vector long long or vector long are passed and 10427 returned using the same method as other vectors with the VSX 10428 instruction set. Previously GCC did not adhere to the ABI for 10429 128-bit vectors with 64-bit integer base types (PR 48857). This 10430 will also be fixed in the GCC 4.6.1 and 4.5.4 releases. 10431 * A new option -mno-pointers-to-nested-functions was added to allow 10432 AIX 32-bit/64-bit and GNU/Linux 64-bit PowerPC users to specify 10433 that the compiler should not load up the chain register (r11) 10434 before calling a function through a pointer. If you use this 10435 option, you cannot call nested functions through a pointer, or call 10436 other languages that might use the static chain. 10437 * A new option msave-toc-indirect was added to allow AIX 10438 32-bit/64-bit and GNU/Linux 64-bit PowerPC users control whether we 10439 save the TOC in the prologue for indirect calls or generate the 10440 save inline. This can speed up some programs that call through a 10441 function pointer a lot, but it can slow down other functions that 10442 only call through a function pointer in exceptional cases. 10443 * The PowerPC port will now enable machine-specific built-in 10444 functions when the user switches the target machine using the 10445 #pragma GCC target or __attribute__ ((__target__ ("target"))) code 10446 sequences. In addition, the target macros are updated. However, due 10447 to the way the -save-temps switch is implemented, you won't see the 10448 effect of these additional macros being defined in preprocessor 10449 output. 10450 10451 SH 10452 10453 * A new option -msoft-atomic has been added. When it is specified, 10454 GCC will generate GNU/Linux-compatible gUSA atomic sequences for 10455 the new __atomic routines. 10456 * Since it is neither supported by GAS nor officially documented, 10457 code generation for little endian SH2A has been disabled. 10458 Specifying -ml with -m2a* will now result in a compiler error. 10459 * The defunct -mbranch-cost option has been fixed. 10460 * Some improvements to the generated code of: 10461 + Utilization of the tst #imm,R0 instruction. 10462 + Dynamic shift instructions on SH2A. 10463 + Integer absolute value calculations. 10464 * The -mdiv= option for targets other than SHmedia has been fixed and 10465 documented. 10466 10467 SPARC 10468 10469 * The option -mflat has been reinstated. When it is specified, the 10470 compiler will generate code for a single register window model. 10471 This is essentially a new implementation and the corresponding 10472 debugger support has been added to GDB 7.4. 10473 * Support for the options -mtune=native and -mcpu=native has been 10474 added on selected native platforms (GNU/Linux and Solaris). 10475 * Support for the SPARC T3 (Niagara 3) processor has been added. 10476 * VIS: 10477 + An intrinsics header visintrin.h has been added. 10478 + Builtin intrinsics for the VIS 1.0 edge handling and pixel 10479 compare instructions have been added. 10480 + The little-endian version of alignaddr is now supported. 10481 + When possible, VIS builtins are marked const, which should 10482 increase the compiler's ability to optimize VIS operations. 10483 + The compiler now properly tracks the %gsr register and how it 10484 behaves as an input for various VIS instructions. 10485 + Akin to fzero, the compiler can now generate fone instructions 10486 in order to set all of the bits of a floating-point register 10487 to 1. 10488 + The documentation for the VIS intrinsics in the GCC manual has 10489 been brought up to date and many inaccuracies were fixed. 10490 + Intrinsics for the VIS 2.0 bmask, bshuffle, and 10491 non-condition-code setting edge instructions have been added. 10492 Their availability is controlled by the new -mvis2 and 10493 -mno-vis2 options. They are enabled by default on 10494 UltraSPARC-III and later CPUs. 10495 * Support for UltraSPARC Fused Multiply-Add floating-point extensions 10496 has been added. These instructions are enabled by default on SPARC 10497 T3 (Niagara 3) and later CPUs. 10498 10499 TILE-Gx/TILEPro 10500 10501 * Support has been added for the Tilera TILE-Gx and TILEPro families 10502 of processors. 10503 10504 Other significant improvements 10505 10506 * A new option (-grecord-gcc-switches) was added that appends 10507 compiler command-line options that might affect code generation to 10508 the DW_AT_producer attribute string in the DWARF debugging 10509 information. 10510 * GCC now supports various new GNU extensions to the DWARF debugging 10511 information format, like [40]entry value and [41]call site 10512 information, [42]typed DWARF stack or [43]a more compact macro 10513 representation. Support for these extensions has been added to GDB 10514 7.4. They can be disabled through the -gstrict-dwarf command-line 10515 option. 10516 10517 GCC 4.7.1 10518 10519 This is the [44]list of problem reports (PRs) from GCC's bug tracking 10520 system that are known to be fixed in the 4.7.1 release. This list might 10521 not be complete (that is, it is possible that some PRs that have been 10522 fixed are not listed here). 10523 10524 The Go front end in the 4.7.1 release fully supports the [45]Go 1 10525 language standard. 10526 10527 GCC 4.7.2 10528 10529 This is the [46]list of problem reports (PRs) from GCC's bug tracking 10530 system that are known to be fixed in the 4.7.2 release. This list might 10531 not be complete (that is, it is possible that some PRs that have been 10532 fixed are not listed here). 10533 10534 GCC 4.7.3 10535 10536 This is the [47]list of problem reports (PRs) from GCC's bug tracking 10537 system that are known to be fixed in the 4.7.3 release. This list might 10538 not be complete (that is, it is possible that some PRs that have been 10539 fixed are not listed here). 10540 10541 GCC 4.7.4 10542 10543 This is the [48]list of problem reports (PRs) from GCC's bug tracking 10544 system that are known to be fixed in the 4.7.4 release. This list might 10545 not be complete (that is, it is possible that some PRs that have been 10546 fixed are not listed here). 10547 10548 10549 For questions related to the use of GCC, please consult these web 10550 pages and the [49]GCC manuals. If that fails, the 10551 [50]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10552 web pages and the development of GCC are welcome on our developer 10553 list at [51]gcc (a] gcc.gnu.org. All of [52]our lists have public 10554 archives. 10555 10556 Copyright (C) [53]Free Software Foundation, Inc. Verbatim copying and 10557 distribution of this entire article is permitted in any medium, 10558 provided this notice is preserved. 10559 10560 These pages are [54]maintained by the GCC team. Last modified 10561 2023-03-29. 10562 10563 References 10564 10565 1. https://gcc.gnu.org/ml/gcc-patches/2011-03/msg01263.html 10566 2. http://savannah.nongnu.org/bugs/?35407 10567 3. https://gcc.gnu.org/PR18145 10568 4. https://gcc.gnu.org/gcc-4.7/porting_to.html 10569 5. https://gcc.gnu.org/wiki/TransactionalMemory 10570 6. https://gcc.gnu.org/wiki/Atomic/GCCMM 10571 7. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10572 8. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10573 9. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10574 10. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10575 11. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10576 12. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 10577 13. https://gcc.gnu.org/PR14258 10578 14. https://gcc.gnu.org/PR35688 10579 15. https://gcc.gnu.org/onlinedocs/gcc-4.7.4/libstdc++/manual/manual/status.html#status.iso.2011 10580 16. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 10581 17. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Optimize-Options.html#index-Ofast-689 10582 18. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfno-protect-parens_007d-270 10583 19. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 10584 20. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfrontend-optimize_007d-275 10585 21. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWfunction-elimination_007d-170 10586 22. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfaggressive-function-elimination_007d-270 10587 23. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWreal-q-constant_007d-149 10588 24. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/SELECTED_005fREAL_005fKIND.html 10589 25. https://learn.microsoft.com/en-us/windows/win32/wer/collecting-user-mode-dumps 10590 26. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Debugging-Options.html#index-g_t_0040code_007bfno-backtrace_007d-183 10591 27. https://gcc.gnu.org/wiki/Fortran2003Status 10592 28. https://gcc.gnu.org/wiki/OOP 10593 29. https://gcc.gnu.org/wiki/Fortran2008Status 10594 30. https://gcc.gnu.org/wiki/Coarray 10595 31. https://gcc.gnu.org/wiki/CoarrayLib 10596 32. https://gcc.gnu.org/wiki/TS29113Status 10597 33. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bstd_003d_007d_0040var_007bstd_007d-option-53 10598 34. https://go.dev/doc/go1 10599 35. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Named-Address-Spaces.html 10600 36. http://www.nongnu.org/avr-libc/ 10601 37. https://gcc.gnu.org/PR54461 10602 38. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/AVR-Built%5f002din-Functions.html 10603 39. https://sites.google.com/site/x32abi/ 10604 40. https://dwarfstd.org/issues/100909.1.html 10605 41. https://dwarfstd.org/issues/100909.2.html 10606 42. https://dwarfstd.org/issues/140425.1.html 10607 43. https://dwarfstd.org/issues/110722.1.html 10608 44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.1 10609 45. https://go.dev/doc/go1 10610 46. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.2 10611 47. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.3 10612 48. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.4 10613 49. https://gcc.gnu.org/onlinedocs/ 10614 50. mailto:gcc-help (a] gcc.gnu.org 10615 51. mailto:gcc (a] gcc.gnu.org 10616 52. https://gcc.gnu.org/lists.html 10617 53. https://www.fsf.org/ 10618 54. https://gcc.gnu.org/about.html 10619 ====================================================================== 10620 http://gcc.gnu.org/gcc-4.6/index.html 10621 10622 GCC 4.6 Release Series 10623 10624 (This release series is no longer supported.) 10625 10626 April 12, 2013 10627 10628 The [1]GNU project and the GCC developers are pleased to announce the 10629 release of GCC 4.6.4. 10630 10631 This release is a bug-fix release, containing fixes for regressions in 10632 GCC 4.6.3 relative to previous releases of GCC. 10633 10634 Release History 10635 10636 GCC 4.6.4 10637 April 12, 2013 ([2]changes, [3]documentation) 10638 10639 GCC 4.6.3 10640 March 1, 2012 ([4]changes, [5]documentation) 10641 10642 GCC 4.6.2 10643 October 26, 2011 ([6]changes, [7]documentation) 10644 10645 GCC 4.6.1 10646 June 27, 2011 ([8]changes, [9]documentation) 10647 10648 GCC 4.6.0 10649 March 25, 2011 ([10]changes, [11]documentation) 10650 10651 References and Acknowledgements 10652 10653 GCC used to stand for the GNU C Compiler, but since the compiler 10654 supports several other languages aside from C, it now stands for the 10655 GNU Compiler Collection. 10656 10657 A list of [12]successful builds is updated as new information becomes 10658 available. 10659 10660 The GCC developers would like to thank the numerous people that have 10661 contributed new features, improvements, bug fixes, and other changes as 10662 well as test results to GCC. This [13]amazing group of volunteers is 10663 what makes GCC successful. 10664 10665 For additional information about GCC please refer to the [14]GCC 10666 project web site or contact the [15]GCC development mailing list. 10667 10668 To obtain GCC please use [16]our mirror sites or [17]our version 10669 control system. 10670 10671 10672 For questions related to the use of GCC, please consult these web 10673 pages and the [18]GCC manuals. If that fails, the 10674 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10675 web pages and the development of GCC are welcome on our developer 10676 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 10677 archives. 10678 10679 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 10680 distribution of this entire article is permitted in any medium, 10681 provided this notice is preserved. 10682 10683 These pages are [23]maintained by the GCC team. Last modified 10684 2022-10-26. 10685 10686 References 10687 10688 1. http://www.gnu.org/ 10689 2. http://gcc.gnu.org/gcc-4.6/changes.html 10690 3. https://gcc.gnu.org/onlinedocs/4.6.4/ 10691 4. http://gcc.gnu.org/gcc-4.6/changes.html 10692 5. https://gcc.gnu.org/onlinedocs/4.6.3/ 10693 6. http://gcc.gnu.org/gcc-4.6/changes.html 10694 7. https://gcc.gnu.org/onlinedocs/4.6.2/ 10695 8. http://gcc.gnu.org/gcc-4.6/changes.html 10696 9. https://gcc.gnu.org/onlinedocs/4.6.1/ 10697 10. http://gcc.gnu.org/gcc-4.6/changes.html 10698 11. https://gcc.gnu.org/onlinedocs/4.6.0/ 10699 12. http://gcc.gnu.org/gcc-4.6/buildstat.html 10700 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 10701 14. http://gcc.gnu.org/index.html 10702 15. mailto:gcc (a] gcc.gnu.org 10703 16. http://gcc.gnu.org/mirrors.html 10704 17. http://gcc.gnu.org/git.html 10705 18. https://gcc.gnu.org/onlinedocs/ 10706 19. mailto:gcc-help (a] gcc.gnu.org 10707 20. mailto:gcc (a] gcc.gnu.org 10708 21. https://gcc.gnu.org/lists.html 10709 22. https://www.fsf.org/ 10710 23. https://gcc.gnu.org/about.html 10711 ====================================================================== 10712 http://gcc.gnu.org/gcc-4.6/changes.html 10713 10714 GCC 4.6 Release Series 10715 Changes, New Features, and Fixes 10716 10717 Caveats 10718 10719 * The options -b <machine> and -V <version> have been removed because 10720 they were unreliable. Instead, users should directly run 10721 <machine>-gcc when cross-compiling, or <machine>-gcc-<version> to 10722 run a different version of gcc. 10723 * GCC now has stricter checks for invalid command-line options. In 10724 particular, when gcc was called to link object files rather than 10725 compile source code, it would previously accept and ignore all 10726 options starting with --, including linker options such as 10727 --as-needed and --export-dynamic, although such options would 10728 result in errors if any source code was compiled. Such options, if 10729 unknown to the compiler, are now rejected in all cases; if the 10730 intent was to pass them to the linker, options such as 10731 -Wl,--as-needed should be used. 10732 * Versions of the GNU C library up to and including 2.11.1 included 10733 an [1]incorrect implementation of the cproj function. GCC optimizes 10734 its builtin cproj according to the behavior specified and allowed 10735 by the ISO C99 standard. If you want to avoid discrepancies between 10736 the C library and GCC's builtin transformations when using cproj in 10737 your code, use GLIBC 2.12 or later. If you are using an older GLIBC 10738 and actually rely on the incorrect behavior of cproj, then you can 10739 disable GCC's transformations using -fno-builtin-cproj. 10740 * The C-only intermodule optimization framework (IMA, enabled by 10741 -combine) has been removed in favor of the new generic link-time 10742 optimization framework (LTO) introduced in [2]GCC 4.5.0. 10743 * GCC now ships with the LGPL-licensed libquadmath library, which 10744 provides quad-precision mathematical functions for targets with a 10745 __float128 datatype. __float128 is available for targets on 32-bit 10746 x86, x86-64 and Itanium architectures. The libquadmath library is 10747 automatically built on such targets when building the Fortran 10748 compiler. 10749 * New -Wunused-but-set-variable and -Wunused-but-set-parameter 10750 warnings were added for C, C++, Objective-C and Objective-C++. 10751 These warnings diagnose variables respective parameters which are 10752 only set in the code and never otherwise used. Usually such 10753 variables are useless and often even the value assigned to them is 10754 computed needlessly, sometimes expensively. The 10755 -Wunused-but-set-variable warning is enabled by default by -Wall 10756 flag and -Wunused-but-set-parameter by -Wall -Wextra flags. 10757 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 10758 rules for the layout of vectors that could lead to wrong code being 10759 generated. Vectors larger than 8 bytes in size are now by default 10760 aligned to an 8-byte boundary. This is an ABI change: code that 10761 makes explicit use of vector types may be incompatible with binary 10762 objects built with older versions of GCC. Auto-vectorized code is 10763 not affected by this change. (This change affects GCC versions 10764 4.6.4 and later, with the exception of versions 4.7.0 and 4.7.1.) 10765 * On AVR, variables with the progmem attribute to locate data in 10766 flash memory must be qualified as const. 10767 * Support for a number of older systems and recently unmaintained or 10768 untested target ports of GCC has been declared obsolete in GCC 4.6. 10769 Unless there is activity to revive them, the next release of GCC 10770 will have their sources permanently removed. 10771 All GCC ports for the following processor architectures have been 10772 declared obsolete: 10773 + Argonaut ARC (arc-*) 10774 + National Semiconductor CRX (crx-*) 10775 + Motorola 68HC11 and 68HC12 (m68hc11-*-*, m6811-*-*, 10776 m68hc12-*-*, m6812-*-*) 10777 + Sunplus S+core (score-*) 10778 The following ports for individual systems on particular 10779 architectures have been obsoleted: 10780 + Interix (i[34567]86-*-interix3*) 10781 + NetWare x86 (i[3456x]86-*-netware*) 10782 + Generic ARM PE (arm-*-pe* other than arm*-wince-pe*) 10783 + MCore PE (mcore-*-pe*) 10784 + SH SymbianOS (sh*-*-symbianelf*) 10785 + GNU Hurd on Alpha and PowerPC (alpha*-*-gnu*, powerpc*-*-gnu*) 10786 + M68K uClinux old ABI (m68k-*-uclinuxoldabi*) 10787 + a.out NetBSD (arm*-*-netbsd*, i[34567]86-*-netbsd*, 10788 vax-*-netbsd*, but not *-*-netbsdelf*) 10789 The i[34567]86-*-pe alias for Cygwin targets has also been 10790 obsoleted; users should configure for i[34567]86-*-cygwin* instead. 10791 Certain configure options to control the set of libraries built 10792 with GCC on some targets have been obsoleted. On ARM targets, the 10793 options --disable-fpu, --disable-26bit, --disable-underscore, 10794 --disable-interwork, --disable-biendian and --disable-nofmult have 10795 been obsoleted. On MIPS targets, the options 10796 --disable-single-float, --disable-biendian and --disable-softfloat 10797 have been obsoleted. 10798 * Support has been removed for all the [3]configurations obsoleted in 10799 GCC 4.5. 10800 * More information on porting to GCC 4.6 from previous versions of 10801 GCC can be found in the [4]porting guide for this release. 10802 10803 General Optimizer Improvements 10804 10805 * A new general optimization level, -Ofast, has been introduced. It 10806 combines the existing optimization level -O3 with options that can 10807 affect standards compliance but result in better optimized code. 10808 For example, -Ofast enables -ffast-math. 10809 * Link-time optimization improvements: 10810 + The [5]Scalable Whole Program Optimizer (WHOPR) project has 10811 stabilized to the point of being usable. It has become the 10812 default mode when using the LTO optimization model. Link time 10813 optimization can now split itself into multiple parallel 10814 compilations. Parallelism is controlled with -flto=n (where n 10815 specifies the number of compilations to execute in parallel). 10816 GCC can also cooperate with a GNU make job server by 10817 specifying the -flto=jobserver option and adding + to the 10818 beginning of the Makefile rule executing the linker. 10819 Classical LTO mode can be enforced by -flto-partition=none. 10820 This may result in small code quality improvements. 10821 + A large number of bugs were fixed. GCC itself, Mozilla Firefox 10822 and other large applications can be built with LTO enabled. 10823 + The linker plugin support improvements 10824 o Linker plugin is now enabled by default when the linker 10825 is detected to have plugin support. This is the case for 10826 GNU ld 2.21.51 or newer (on ELF and Cygwin targets) and 10827 the Gold linker on ELF targets. Plugin support of the 10828 Apple linker on Darwin is not compatible with GCC. The 10829 linker plugin can also be controlled by the 10830 -fuse-linker-plugin command-line option. 10831 o Resolution information from the linker plugin is used to 10832 drive whole program assumptions. Use of the linker plugin 10833 results in more aggressive optimization on binaries and 10834 on shared libraries that use the hidden visibility 10835 attribute. Consequently the use of -fwhole-program is not 10836 necessary in addition to LTO. 10837 + Hidden symbols used from non-LTO objects now have to be 10838 explicitly annotated with externally_visible when the linker 10839 plugin is not used. 10840 + C++ inline functions and virtual tables are now privatized 10841 more aggressively, leading to better inter-procedural 10842 optimization and faster dynamic linking. 10843 + Memory usage and intermediate language streaming performance 10844 have been improved. 10845 + Static constructors and destructors from individual units are 10846 inlined into a single function. This can significantly improve 10847 startup times of large C++ applications where static 10848 constructors are very common. For example, static constructors 10849 are used when including the iostream header. 10850 + Support for the Ada language has been added. 10851 * Interprocedural optimization improvements 10852 + The interprocedural framework was re-tuned for link time 10853 optimization. Several scalability issues were resolved. 10854 + Improved auto-detection of const and pure functions. Newly, 10855 noreturn functions are auto-detected. 10856 The [6]-Wsuggest-attribute=[const|pure|noreturn] flag is 10857 available that informs users when adding attributes to headers 10858 might improve code generation. 10859 + A number of inlining heuristic improvements. In particular: 10860 o Partial inlining is now supported and enabled by default 10861 at -O2 and greater. The feature can be controlled via 10862 -fpartial-inlining. 10863 Partial inlining splits functions with short hot path to 10864 return. This allows more aggressive inlining of the hot 10865 path leading to better performance and often to code size 10866 reductions (because cold parts of functions are not 10867 duplicated). 10868 o Scalability for large compilation units was improved 10869 significantly. 10870 o Inlining of callbacks is now more aggressive. 10871 o Virtual methods are considered for inlining when the 10872 caller is inlined and devirtualization is then possible. 10873 o Inlining when optimizing for size (either in cold regions 10874 of a program or when compiling with -Os) was improved to 10875 better handle C++ programs with larger abstraction 10876 penalty, leading to smaller and faster code. 10877 + The IPA reference optimization pass detecting global variables 10878 used or modified by functions was strengthened and sped up. 10879 + Functions whose address was taken are now optimized out when 10880 all references to them are dead. 10881 + A new inter-procedural static profile estimation pass detects 10882 functions that are executed once or unlikely to be executed. 10883 Unlikely executed functions are optimized for size. Functions 10884 executed once are optimized for size except for the inner 10885 loops. 10886 + On most targets with named section support, functions used 10887 only at startup (static constructors and main), functions used 10888 only at exit and functions detected to be cold are placed into 10889 separate text segment subsections. This extends the 10890 -freorder-functions feature and is controlled by the same 10891 switch. The goal is to improve the startup time of large C++ 10892 programs. 10893 Proper function placement requires linker support. GNU ld 10894 2.21.51 on ELF targets was updated to place those functions 10895 together within the text section leading to better code 10896 locality and faster startup times of large C++ programs. The 10897 feature is also supported in the Apple linker. Support in the 10898 gold linker is planned. 10899 * A new switch -fstack-usage has been added. It makes the compiler 10900 output stack usage information for the program, on a per-function 10901 basis, in an auxiliary file. 10902 * A new switch -fcombine-stack-adjustments has been added. It can be 10903 used to enable or disable the compiler's stack-slot combining pass 10904 which before was enabled automatically at -O1 and above, but could 10905 not be controlled on its own. 10906 * A new switch -fstrict-volatile-bitfields has been added. Using it 10907 indicates that accesses to volatile bitfields should use a single 10908 access of the width of the field's type. This option can be useful 10909 for precisely defining and accessing memory-mapped peripheral 10910 registers from C or C++. 10911 10912 Compile time and memory usage improvements 10913 10914 * Datastructures used by the dataflow framework in GCC were 10915 reorganized for better memory usage and more cache locality. 10916 Compile time is improved especially on units with large functions 10917 (possibly resulting from a lot of inlining) not fitting into the 10918 processor cache. The compile time of the GCC C compiler binary with 10919 link-time optimization went down by over 10% (benchmarked on x86-64 10920 target). 10921 10922 New Languages and Language specific improvements 10923 10924 Ada 10925 10926 * Stack checking has been improved on selected architectures (Alpha, 10927 IA-32/x86-64, RS/6000 and SPARC): it now will detect stack 10928 overflows in all cases on these architectures. 10929 * Initial support for Ada 2012 has been added. 10930 10931 C family 10932 10933 * A new warning, enabled by -Wdouble-promotion, has been added that 10934 warns about cases where a value of type float is implicitly 10935 promoted to double. This is especially helpful for CPUs that handle 10936 the former in hardware, but emulate the latter in software. 10937 * A new function attribute leaf was introduced. This attribute allows 10938 better inter-procedural optimization across calls to functions that 10939 return to the current unit only via returning or exception 10940 handling. This is the case for most library functions that have no 10941 callbacks. 10942 * Support for a new data type __int128 for targets having wide enough 10943 machine-mode support. 10944 * The new function attribute callee_pop_aggregate allows to specify 10945 if the caller or callee is responsible for popping the aggregate 10946 return pointer value from the stack. 10947 * Support for selectively enabling and disabling warnings via #pragma 10948 GCC diagnostic has been added. For instance: 10949 #pragma GCC diagnostic error "-Wuninitialized" 10950 foo(a); /* error is given for this one */ 10951 #pragma GCC diagnostic push 10952 #pragma GCC diagnostic ignored "-Wuninitialized" 10953 foo(b); /* no diagnostic for this one */ 10954 #pragma GCC diagnostic pop 10955 foo(c); /* error is given for this one */ 10956 #pragma GCC diagnostic pop 10957 foo(d); /* depends on command-line options */ 10958 10959 * The -fmax-errors=N option is now supported. Using this option 10960 causes the compiler to exit after N errors have been issued. 10961 10962 C 10963 10964 * There is now experimental support for some features from the 10965 upcoming C1X revision of the ISO C standard. This support may be 10966 selected with -std=c1x, or -std=gnu1x for C1X with GNU extensions. 10967 Note that this support is experimental and may change incompatibly 10968 in future releases for consistency with changes to the C1X standard 10969 draft. The following features are newly supported as described in 10970 the N1539 draft of C1X (with changes agreed at the March 2011 WG14 10971 meeting); some other features were already supported with no 10972 compiler changes being needed, or have some support but not in full 10973 accord with N1539 (as amended). 10974 + Static assertions (_Static_assert keyword) 10975 + Typedef redefinition 10976 + New macros in <float.h> 10977 + Anonymous structures and unions 10978 * The new -fplan9-extensions option directs the compiler to support 10979 some extensions for anonymous struct fields which are implemented 10980 by the Plan 9 compiler. A pointer to a struct may be automatically 10981 converted to a pointer to an anonymous field when calling a 10982 function, in order to make the types match. An anonymous struct 10983 field whose type is a typedef name may be referred to using the 10984 typedef name. 10985 10986 C++ 10987 10988 * Improved [7]experimental support for the upcoming C++0x ISO C++ 10989 standard, including support for constexpr (thanks to Gabriel Dos 10990 Reis and Jason Merrill), nullptr (thanks to Magnus Fromreide), 10991 noexcept, unrestricted unions, range-based for loops (thanks to 10992 Rodrigo Rivas Costa), opaque enum declarations (thanks also to 10993 Rodrigo), implicitly deleted functions and implicit move 10994 constructors. 10995 * When an extern declaration within a function does not match a 10996 declaration in the enclosing context, G++ now properly declares the 10997 name within the namespace of the function rather than the namespace 10998 which was open just before the function definition ([8]c++/43145). 10999 * GCC now warns by default when casting integers to larger pointer 11000 types. These warnings can be disabled with the option 11001 -Wno-int-to-pointer-cast, which is now also available in C++. 11002 * G++ no longer optimizes using the assumption that a value of 11003 enumeration type will fall within the range specified by the 11004 standard, since that assumption is easily violated with a 11005 conversion from integer type ([9]c++/43680). The old behavior can 11006 be restored with -fstrict-enums. 11007 * The new -fnothrow-opt flag changes the semantics of a throw() 11008 exception specification to match the proposed semantics of the 11009 noexcept specification: just call terminate if an exception tries 11010 to propagate out of a function with such an exception 11011 specification. This dramatically reduces or eliminates the code 11012 size overhead from adding the exception specification. 11013 * The new -Wnoexcept flag will suggest adding a noexcept qualifier to 11014 a function that the compiler can tell doesn't throw if it would 11015 change the value of a noexcept expression. 11016 * The -Wshadow option now warns if a local variable or type 11017 declaration shadows another type in C++. Note that the compiler 11018 will not warn if a local variable shadows a struct/class/enum, but 11019 will warn if it shadows an explicit typedef. 11020 * When an identifier is not found in the current scope, G++ now 11021 offers suggestions about which identifier might have been intended. 11022 * G++ now issues clearer diagnostics for missing semicolons after 11023 class, struct, and union definitions. 11024 * G++ now issues clearer diagnostics for missing semicolons after 11025 class member declarations. 11026 * G++ now issues clearer diagnostics when a colon is used in a place 11027 where a double-colon was intended. 11028 * G++ no longer accepts mutable on reference members ([10]c++/33558). 11029 Use -fpermissive to allow the old, non-conforming behaviour. 11030 * A few mangling fixes have been made, to attribute const/volatile on 11031 function pointer types, decltype of a plain decl, and use of a 11032 function parameter in the declaration of another parameter. By 11033 default the compiler still uses the old mangling, but emits aliases 11034 with the new mangling on targets that support strong aliases. Users 11035 can switch over entirely to the new mangling with -fabi-version=5 11036 or -fabi-version=0. -Wabi will now warn about code that uses the 11037 old mangling. 11038 * In 4.6.0 and 4.6.1 G++ no longer allows objects of const-qualified 11039 type to be default initialized unless the type has a user-declared 11040 default constructor. In 4.6.2 G++ implements the proposed 11041 resolution of [11]DR 253, so default initialization is allowed if 11042 it initializes all subobjects. Code that fails to compile can be 11043 fixed by providing an initializer e.g. 11044 struct A { A(); }; 11045 struct B : A { int i; }; 11046 const B b = B(); 11047 Use -fpermissive to allow the old, non-conforming behaviour. 11048 11049 Runtime Library (libstdc++) 11050 11051 * [12]Improved experimental support for the upcoming ISO C++ 11052 standard, C++0x, including using constexpr and nullptr. 11053 * Performance improvements to the [13]Debug Mode, thanks to Franois 11054 Dumont. 11055 * Atomic operations used for reference-counting are annotated so that 11056 they can be understood by race detectors such as Helgrind, see 11057 [14]Data Race Hunting. 11058 * Most libstdc++ standard headers have been changed to no longer 11059 include the cstddef header as an implementation detail. Code that 11060 relied on that header being included as side-effect of including 11061 other standard headers will need to include cstddef explicitly. 11062 11063 Fortran 11064 11065 * On systems supporting the libquadmath library, GNU Fortran now also 11066 supports a quad-precision, kind=16 floating-point data type 11067 (REAL(16), COMPLEX(16)). As the data type is not fully supported in 11068 hardware, calculations might be one to two orders of magnitude 11069 slower than with the 4, 8 or 10 bytes floating-point data types. 11070 This change does not affect systems which support REAL(16) in 11071 hardware nor those which do not support libquadmath. 11072 * Much improved compile time for large array constructors. 11073 * In order to reduce execution time and memory consumption, use of 11074 temporary arrays in assignment expressions is avoided for many 11075 cases. The compiler now reverses loops in order to avoid generating 11076 a temporary array where possible. 11077 * Improved diagnostics, especially with -fwhole-file. 11078 * The -fwhole-file flag is now enabled by default. This improves code 11079 generation and diagnostics. It can be disabled using the deprecated 11080 -fno-whole-file flag. 11081 * Support the generation of Makefile dependencies via the [15]-M... 11082 flags of GCC; you may need to specify the -cpp option in addition. 11083 The dependencies take modules, Fortran's include, and CPP's 11084 #include into account. Note: Using -M for the module path is no 11085 longer supported, use -J instead. 11086 * The flag -Wconversion has been modified to only issue warnings 11087 where a conversion leads to information loss. This drastically 11088 reduces the number of warnings; -Wconversion is thus now enabled 11089 with -Wall. The flag -Wconversion-extra has been added and also 11090 warns about other conversions; -Wconversion-extra typically issues 11091 a huge number of warnings, most of which can be ignored. 11092 * A new command-line option -Wunused-dummy-argument warns about 11093 unused dummy arguments and is included in -Wall. Before, 11094 -Wunused-variable also warned about unused dummy arguments. 11095 * Fortran 2003 support has been extended: 11096 + Improved support for polymorphism between libraries and 11097 programs and for complicated inheritance patterns (cf. 11098 [16]object-oriented programming). 11099 + Experimental support of the ASSOCIATE construct. 11100 + In pointer assignments it is now possible to specify the lower 11101 bounds of the pointer and, for a rank-1 or a simply contiguous 11102 data-target, to remap the bounds. 11103 + Automatic (re)allocation: In intrinsic assignments to 11104 allocatable variables the left-hand side will be automatically 11105 allocated (if unallocated) or reallocated (if the shape or 11106 type parameter is different). To avoid the small performance 11107 penalty, you can use a(:) = ... instead of a = ... for arrays 11108 and character strings - or disable the feature using -std=f95 11109 or -fno-realloc-lhs. 11110 + Deferred type parameter: For scalar allocatable and pointer 11111 variables the character length can be deferred. 11112 + Namelist variables with allocatable and pointer attribute and 11113 nonconstant length type parameter are supported. 11114 * Fortran 2008 support has been extended: 11115 + Experimental [17]coarray support (for one image only, i.e. 11116 num_images() == 1); use the [18]-fcoarray=single flag to 11117 enable it. 11118 + The STOP and the new ERROR STOP statements now support all 11119 constant expressions. 11120 + Support for the CONTIGUOUS attribute. 11121 + Support for ALLOCATE with MOLD. 11122 + Support for the STORAGE_SIZE intrinsic inquiry function. 11123 + Support of the NORM2 and PARITY intrinsic functions. 11124 + The following bit intrinsics were added: POPCNT and POPPAR for 11125 counting the number of 1 bits and returning the parity; BGE, 11126 BGT, BLE, and BLT for bitwise comparisons; DSHIFTL and DSHIFTR 11127 for combined left and right shifts, MASKL and MASKR for simple 11128 left and right justified masks, MERGE_BITS for a bitwise merge 11129 using a mask, SHIFTA, SHIFTL and SHIFTR for shift operations, 11130 and the transformational bit intrinsics IALL, IANY and 11131 IPARITY. 11132 + Support of the EXECUTE_COMMAND_LINE intrinsic subroutine. 11133 + Support for the IMPURE attribute for procedures, which allows 11134 for ELEMENTAL procedures without the restrictions of PURE. 11135 + Null pointers (including NULL()) and not allocated variables 11136 can be used as actual argument to optional non-pointer, 11137 non-allocatable dummy arguments, denoting an absent argument. 11138 + Non-pointer variables with TARGET attribute can be used as 11139 actual argument to POINTER dummies with INTENT(IN) 11140 + Pointers including procedure pointers and those in a derived 11141 type (pointer components) can now be initialized by a target 11142 instead of only by NULL. 11143 + The EXIT statement (with construct-name) can now be used to 11144 leave not only the DO but also the ASSOCIATE, BLOCK, IF, 11145 SELECT CASE and SELECT TYPE constructs. 11146 + Internal procedures can now be used as actual argument. 11147 + The named constants INTEGER_KINDS, LOGICAL_KINDS, REAL_KINDS 11148 and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV 11149 have been added; these arrays contain the supported kind 11150 values for the respective types. 11151 + The module procedures C_SIZEOF of the intrinsic module 11152 ISO_C_BINDINGS and COMPILER_VERSION and COMPILER_OPTIONS of 11153 ISO_FORTRAN_ENV have been implemented. 11154 + Minor changes: obsolescence diagnostics for ENTRY was added 11155 for -std=f2008; a line may start with a semicolon; for 11156 internal and module procedures END can be used instead of END 11157 SUBROUTINE and END FUNCTION; SELECTED_REAL_KIND now also takes 11158 a RADIX argument; intrinsic types are supported for 11159 TYPE(intrinsic-type-spec); multiple type-bound procedures can 11160 be declared in a single PROCEDURE statement; implied-shape 11161 arrays are supported for named constants (PARAMETER). The 11162 transformational, three argument versions of BESSEL_JN and 11163 BESSEL_YN were added - the elemental, two-argument version had 11164 been added in GCC 4.4; note that the transformational 11165 functions use a recurrence algorithm. 11166 11167 Go 11168 11169 Support for the Go programming language has been added to GCC. It is 11170 not enabled by default when you build GCC; use the --enable-languages 11171 configure option to build it. The driver program for compiling Go code 11172 is gccgo. 11173 11174 Go is currently known to work on GNU/Linux and RTEMS. Solaris support 11175 is in progress. It may or may not work on other platforms. 11176 11177 Objective-C and Objective-C++ 11178 11179 * The -fobjc-exceptions flag is now required to enable Objective-C 11180 exception and synchronization syntax (introduced by the keywords 11181 @try, @catch, @finally and @synchronized). 11182 * A number of Objective-C 2.0 features and extensions are now 11183 supported by GCC. These features are enabled by default; you can 11184 disable them by using the new -fobjc-std=objc1 command-line option. 11185 * The Objective-C 2.0 dot-syntax is now supported. It is an 11186 alternative syntax for using getters and setters; object.count is 11187 automatically converted into [object count] or [object setCount: 11188 ...] depending on context; for example if (object.count > 0) is 11189 automatically compiled into the equivalent of if ([object count] > 11190 0) while object.count = 0; is automatically compiled into the 11191 equivalent ot [object setCount: 0];. The dot-syntax can be used 11192 with instance and class objects and with any setters or getters, no 11193 matter if they are part of a declared property or not. 11194 * Objective-C 2.0 declared properties are now supported. They are 11195 declared using the new @property keyword, and are most commonly 11196 used in conjunction with the new Objective-C 2.0 dot-syntax. The 11197 nonatomic, readonly, readwrite, assign, retain, copy, setter and 11198 getter attributes are all supported. Marking declared properties 11199 with __attribute__ ((deprecated)) is supported too. 11200 * The Objective-C 2.0 @synthesize and @dynamic keywords are 11201 supported. @synthesize causes the compiler to automatically 11202 synthesize a declared property, while @dynamic is used to disable 11203 all warnings for a declared property for which no implementation is 11204 provided at compile time. Synthesizing declared properties requires 11205 runtime support in most useful cases; to be able to use it with the 11206 GNU runtime, appropriate helper functions have been added to the 11207 GNU Objective-C runtime ABI, and are implemented by the GNU 11208 Objective-C runtime library shipped with GCC. 11209 * The Objective-C 2.0 fast enumeration syntax is supported in 11210 Objective-C. This is currently not yet available in Objective-C++. 11211 Fast enumeration requires support in the runtime, and such support 11212 has been added to the GNU Objective-C runtime library (shipped with 11213 GCC). 11214 * The Objective-C 2.0 @optional keyword is supported. It allows you 11215 to mark methods or properties in a protocol as optional as opposed 11216 to required. 11217 * The Objective-C 2.0 @package keyword is supported. It has currently 11218 the same effect as the @public keyword. 11219 * Objective-C 2.0 method attributes are supported. Currently the 11220 supported attributes are deprecated, sentinel, noreturn and format. 11221 * Objective-C 2.0 method argument attributes are supported. The most 11222 widely used attribute is unused, to mark an argument as unused in 11223 the implementation. 11224 * Objective-C 2.0 class and protocol attributes are supported. 11225 Currently the only supported attribute is deprecated. 11226 * Objective-C 2.0 class extensions are supported. A class extension 11227 has the same syntax as a category declaration with no category 11228 name, and the methods and properties declared in it are added 11229 directly to the main class. It is mostly used as an alternative to 11230 a category to add methods to a class without advertising them in 11231 the public headers, with the advantage that for class extensions 11232 the compiler checks that all the privately declared methods are 11233 actually implemented. 11234 * As a result of these enhancements, GCC can now be used to build 11235 Objective-C and Objective-C++ software that uses Foundation and 11236 other important system frameworks with the NeXT runtime on Darwin 9 11237 and Darwin 10 (OSX 10.5 and 10.6). 11238 * Many bugs in the compiler have been fixed in this release; in 11239 particular, LTO can now be used when compiling Objective-C and 11240 Objective-C++ and the parser is much more robust in dealing with 11241 invalid code. 11242 11243 Runtime Library (libobjc) 11244 11245 * The GNU Objective-C runtime library now defines the macro 11246 __GNU_LIBOBJC__ (with a value that is increased at every release 11247 where there is any change to the API) in objc/objc.h, making it 11248 easy to determine if the GNU Objective-C runtime library is being 11249 used, and if so, which version. Previous versions of the GNU 11250 Objective-C runtime library (and other Objective-C runtime 11251 libraries such as the Apple one) do not define this macro. 11252 * A new Objective-C 2.0 API, almost identical to the one implemented 11253 by the Apple Objective-C runtime, has been implemented in the GNU 11254 Objective-C runtime library. The new API hides the internals of 11255 most runtime structures but provides a more extensive set of 11256 functions to operate on them. It is much easier, for example, to 11257 create or modify classes at runtime. The new API also makes it 11258 easier to port software from Apple to GNU as almost no changes 11259 should be required. The old API is still supported for backwards 11260 compatibility; including the old objc/objc-api.h header file 11261 automatically selects the old API, while including the new 11262 objc/runtime.h header file automatically selects the new API. 11263 Support for the old API is being phased out and upgrading the 11264 software to use the new API is strongly recommended. To check for 11265 the availability of the new API, the __GNU_LIBOBJC__ macro can be 11266 used as older versions of the GNU Objective-C runtime library, 11267 which do not support the new API, do not define such a macro. 11268 * Runtime support for @synchronized has been added. 11269 * Runtime support for Objective-C 2.0 synthesized property accessors 11270 has been added. 11271 * Runtime support for Objective-C 2.0 fast enumeration has been 11272 added. 11273 11274 New Targets and Target Specific Improvements 11275 11276 ARM 11277 11278 * GCC now supports the Cortex-M4 processor implementing the v7-em 11279 version of the architecture using the option -mcpu=cortex-m4. 11280 * Scheduling descriptions for the Cortex-M4, the Neon and the 11281 floating point units of the Cortex-A9 and a pipeline description 11282 for the Cortex-A5 have been added. 11283 * Synchronization primitives such as __sync_fetch_and_add and friends 11284 are now inlined for supported architectures rather than calling 11285 into a kernel helper function. 11286 * SSA loop prefetching is enabled by default for the Cortex-A9 at 11287 -O3. 11288 * Several improvements were committed to improve code generation for 11289 the ARM architecture including a rewritten implementation for load 11290 and store multiples. 11291 * Several enhancements were committed to improve SIMD code generation 11292 for NEON by adding support for widening instructions, misaligned 11293 loads and stores, vector conditionals and support for 64 bit 11294 arithmetic. 11295 * Support was added for the Faraday cores fa526, fa606te, fa626te, 11296 fmp626te, fmp626 and fa726te and can be used with the respective 11297 names as parameters to the -mcpu= option. 11298 * Basic support was added for Cortex-A15 and is available through 11299 -mcpu=cortex-a15. 11300 * GCC for AAPCS configurations now more closely adheres to the AAPCS 11301 specification by enabling -fstrict-volatile-bitfields by default. 11302 11303 IA-32/x86-64 11304 11305 * The new -fsplit-stack option permits programs to use a 11306 discontiguous stack. This is useful for threaded programs, in that 11307 it is no longer necessary to specify the maximum stack size when 11308 creating a thread. This feature is currently only implemented for 11309 32-bit and 64-bit x86 GNU/Linux targets. 11310 * Support for emitting profiler counter calls before function 11311 prologues. This is enabled via a new command-line option -mfentry. 11312 * Optimization for the Intel Core 2 processors is now available 11313 through the -march=core2 and -mtune=core2 options. 11314 * Support for Intel Core i3/i5/i7 processors is now available through 11315 the -march=corei7 and -mtune=corei7 options. 11316 * Support for Intel Core i3/i5/i7 processors with AVX is now 11317 available through the -march=corei7-avx and -mtune=corei7-avx 11318 options. 11319 * Support for AMD Bobcat (family 14) processors is now available 11320 through the -march=btver1 and -mtune=btver1 options. 11321 * Support for AMD Bulldozer (family 15) processors is now available 11322 through the -march=bdver1 and -mtune=bdver1 options. 11323 * The default setting (when not optimizing for size) for 32-bit 11324 GNU/Linux and Darwin x86 targets has been changed to 11325 -fomit-frame-pointer. The default can be reverted to 11326 -fno-omit-frame-pointer by configuring GCC with the 11327 --enable-frame-pointer configure option. 11328 * Darwin, FreeBSD, Solaris 2, MinGW and Cygwin now all support 11329 __float128 on 32-bit and 64-bit x86 targets. 11330 * AVX floating-point arithmetic can now be enabled by default at 11331 configure time with the new --with-fpmath=avx option. 11332 * The SSA loop prefetching pass is enabled when using -O3 when 11333 optimizing for CPUs where prefetching is beneficial (AMD CPUs newer 11334 than K6). 11335 * Support for TBM (Trailing Bit Manipulation) built-in functions and 11336 code generation is available via -mtbm. 11337 * Support for AMD's BMI (Bit Manipulation) built-in functions and 11338 code generation is available via -mbmi. 11339 11340 MicroBlaze 11341 11342 * Support has been added for the Xilinx MicroBlaze softcore processor 11343 (microblaze-elf) embedded target. This configurable processor is 11344 supported on several Xilinx Spartan and Virtex FPGAs. 11345 11346 MIPS 11347 11348 * GCC now supports the Loongson 3A processor. Its canonical -march= 11349 and -mtune= name is loongson3a. 11350 11351 MN10300 / AM33 11352 11353 * The inline assembly register constraint "A" has been renamed "c". 11354 This constraint is used to select a floating-point register that 11355 can be used as the destination of a multiply-accumulate 11356 instruction. 11357 * New inline assembly register constraints "A" and "D" have been 11358 added. These constraint letters resolve to all general registers 11359 when compiling for AM33, and resolve to address registers only or 11360 data registers only when compiling for MN10300. 11361 * The MDR register is represented in the compiler. One can access the 11362 register via the "z" constraint in inline assembly. It can be 11363 marked as clobbered or used as a local register variable via the 11364 "mdr" name. The compiler uses the RETF instruction if the function 11365 does not modify the MDR register, so it is important that inline 11366 assembly properly annotate any usage of the register. 11367 11368 PowerPC/PowerPC64 11369 11370 * GCC now supports the Applied Micro Titan processor with 11371 -mcpu=titan. 11372 * The -mrecip option has been added, which indicates whether the 11373 reciprocal and reciprocal square root instructions should be used. 11374 * The -mveclibabi=mass option can be used to enable the compiler to 11375 autovectorize mathematical functions using the Mathematical 11376 Acceleration Subsystem library. 11377 * The -msingle-pic-base option has been added, which instructs the 11378 compiler to avoid loading the PIC base register in function 11379 prologues. The PIC base register must be initialized by the runtime 11380 system. 11381 * The -mblock-move-inline-limit option has been added, which enables 11382 the user to control the maximum size of inlined memcpy calls and 11383 similar. 11384 * PowerPC64 GNU/Linux support for applications requiring a large TOC 11385 section has been improved. A new command-line option, 11386 -mcmodel=MODEL, controls this feature; valid values for MODEL are 11387 small, medium, or large. 11388 * The Altivec builtin functions vec_ld and vec_st have been modified 11389 to generate the Altivec memory instructions LVX and STVX, even if 11390 the -mvsx option is used. In the initial GCC 4.5 release, these 11391 builtin functions were changed to generate VSX memory reference 11392 instructions instead of Altivec memory instructions, but there are 11393 differences between the two instructions. If the VSX instruction 11394 set is available, you can now use the new builtin functions 11395 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 11396 instructions. 11397 * The GCC compiler on AIX now defaults to a process layout with a 11398 larger data space allowing larger programs to be compiled. 11399 * The GCC long double type on AIX 6.1 and above has reverted to 64 11400 bit double precision, matching the AIX XL compiler default, because 11401 of missing C99 symbols required by the GCC runtime. 11402 * The default processor scheduling model and tuning for PowerPC64 11403 GNU/Linux and for AIX 6.1 and above now is POWER7. 11404 * Starting with GCC 4.6.1, vectors of type vector long long or vector 11405 long are passed and returned in the same method as other vectors 11406 with the VSX instruction set. Previously the GCC compiler did not 11407 adhere to the ABI for 128-bit vectors with 64-bit integer base 11408 types (PR 48857). This is also fixed in the GCC 4.5.4 release. 11409 11410 S/390, zSeries and System z9/z10, IBM zEnterprise z196 11411 11412 * Support for the zEnterprise z196 processor has been added. When 11413 using the -march=z196 option, the compiler will generate code 11414 making use of the following instruction facilities: 11415 + Conditional load/store 11416 + Distinct-operands 11417 + Floating-point-extension 11418 + Interlocked-access 11419 + Population-count 11420 The -mtune=z196 option avoids the compare and branch instructions 11421 as well as the load address instruction with an index register as 11422 much as possible and performs instruction scheduling appropriate 11423 for the new out-of-order pipeline architecture. 11424 * When using the -m31 -mzarch options the generated code still 11425 conforms to the 32-bit ABI but uses the general purpose registers 11426 as 64-bit registers internally. This requires a Linux kernel saving 11427 the whole 64-bit registers when doing a context switch. Kernels 11428 providing that feature indicate that by the 'highgprs' string in 11429 /proc/cpuinfo. 11430 * The SSA loop prefetching pass is enabled when using -O3. 11431 11432 SPARC 11433 11434 * GCC now supports the LEON series of SPARC V8 processors. The code 11435 generated by the compiler can either be tuned to it by means of the 11436 --with-tune=leon configure option and -mtune=leon compilation 11437 option, or the compiler can be built for the sparc-leon-{elf,linux} 11438 and sparc-leon3-{elf,linux} targets directly. 11439 * GCC has stopped sign/zero-extending parameter registers in the 11440 callee for functions taking parameters with sub-word size in 32-bit 11441 mode, since this is redundant with the specification of the ABI. 11442 GCC has never done so in 64-bit mode since this is also redundant. 11443 * The command-line option -mfix-at697f has been added to enable the 11444 documented workaround for the single erratum of the Atmel AT697F 11445 processor. 11446 11447 Operating Systems 11448 11449 Android 11450 11451 * GCC now supports the Bionic C library and provides a convenient way 11452 of building native libraries and applications for the Android 11453 platform. Refer to the documentation of the -mandroid and -mbionic 11454 options for details on building native code. At the moment, Android 11455 support is enabled only for ARM. 11456 11457 Darwin/Mac OS X 11458 11459 * General 11460 + Initial support for CFString types has been added. 11461 This allows GCC to build projects including the system Core 11462 Foundation frameworks. The GCC Objective-C family supports 11463 CFString "toll-free bridged" as per the Mac OS X system tools. 11464 CFString is also recognized in the context of format 11465 attributes and arguments (see the documentation for format 11466 attributes for limitations). At present, 8-bit character types 11467 are supported. 11468 + Object file size reduction. 11469 The Darwin zeroed memory allocators have been re-written to 11470 make more use of .zerofill sections. For non-debug code, this 11471 can reduce object file size significantly. 11472 + Objective-C family 64-bit support (NeXT ABI 2). 11473 Initial support has been added to support 64-bit Objective-C 11474 code using the Darwin/OS X native (NeXT) runtime. ABI version 11475 2 will be selected automatically when 64-bit code is built. 11476 + Objective-C family 32-bit ABI 1. 11477 For 32-bit code ABI 1 is also now also allowed. At present it 11478 must be selected manually using -fobjc-abi-version=1 where 11479 applicable - i.e. on Darwin 9/10 (OS X 10.5/10.6). 11480 * x86 Architecture 11481 + The -mdynamic-no-pic option has been enabled. 11482 Code supporting -mdynamic-no-pic optimization has been added 11483 and is applicable to -m32 builds. The compiler bootstrap uses 11484 the option where appropriate. 11485 + The default value for -mtune= has been changed. 11486 Since Darwin systems are primarily Xeon, Core-2 or similar the 11487 default tuning has been changed to -mtune=core2. 11488 + Enable 128-bit long double (__float128) support on Darwin. 11489 * PPC Architecture 11490 + Darwin64 ABI. 11491 Several significant bugs have been fixed, such that GCC now 11492 produces code compatible with the Darwin64 PowerPC ABI. 11493 + libffi and boehm-gc. 11494 The Darwin ports of the libffi and boehm-gc libraries have 11495 been upgraded to include a Darwin64 implementation. This means 11496 that powerpc*-*-darwin9 platforms may now, for example, build 11497 Java applications with -m64 enabled. 11498 + Plug-in support has been enabled. 11499 + The -fsection-anchors option is now available although, 11500 presently, not heavily tested. 11501 11502 Solaris 2 11503 11504 New Features 11505 11506 * Support symbol versioning with the Sun linker. 11507 * Allow libstdc++ to leverage full ISO C99 support on Solaris 10+. 11508 * Support thread-local storage (TLS) with the Sun assembler on 11509 Solaris 2/x86. 11510 * Support TLS on Solaris 8/9 if prerequisites are met. 11511 * Support COMDAT group with the GNU assembler and recent Sun linker. 11512 * Support the Sun assembler visibility syntax. 11513 * Default Solaris 2/x86 to -march=pentium4 (Solaris 10+) resp. 11514 -march=pentiumpro (Solaris 8/9). 11515 * Don't use SSE on Solaris 8/9 x86 by default. 11516 * Enable 128-bit long double (__float128) support on Solaris 2/x86. 11517 11518 ABI Change 11519 11520 * Change the ABI for returning 8-byte vectors like __m64 in MMX 11521 registers on Solaris 10+/x86 to match the Sun Studio 12.1+ 11522 compilers. This is an incompatible change. If you use such types, 11523 you must either recompile all your code with the new compiler or 11524 use the new -mvect8-ret-in-mem option to remain compatible with 11525 previous versions of GCC and Sun Studio. 11526 11527 Windows x86/x86_64 11528 11529 * Initial support for decimal floating point. 11530 * Support for the __thiscall calling-convention. 11531 * Support for hot-patchable function prologues via the 11532 ms_hook_prologue attribute for x86_64 in addition to 32-bit x86. 11533 * Improvements of stack-probing and stack-allocation mechanisms. 11534 * Support of push/pop-macro pragma as preprocessor command. 11535 With #pragma push_macro("macro-name") the current definition of 11536 macro-name is saved and can be restored with #pragma 11537 pop_macro("macro-name") to its saved definition. 11538 * Enable 128-bit long double (__float128) support on MinGW and 11539 Cygwin. 11540 11541 Other significant improvements 11542 11543 Installation changes 11544 11545 * An install-strip make target is provided that installs stripped 11546 executables, and may install libraries with unneeded or debugging 11547 sections stripped. 11548 * On Power7 systems, there is a potential problem if you build the 11549 GCC compiler with a host compiler using options that enable the VSX 11550 instruction set generation. If the host compiler has been patched 11551 so that the vec_ld and vec_st builtin functions generate Altivec 11552 memory instructions instead of VSX memory instructions, then you 11553 should be able to build the compiler with VSX instruction 11554 generation. 11555 11556 Changes for GCC Developers 11557 11558 Note: these changes concern developers that develop GCC itself or 11559 software that integrates with GCC, such as plugins, and not the general 11560 GCC users. 11561 * The gengtype utility, which previously was internal to the GCC 11562 build process, has been enchanced to provide GC root information 11563 for plugins as necessary. 11564 * The old GC allocation interface of ggc_alloc and friends was 11565 replaced with a type-safe alternative. 11566 11567 GCC 4.6.1 11568 11569 This is the [19]list of problem reports (PRs) from GCC's bug tracking 11570 system that are known to be fixed in the 4.6.1 release. This list might 11571 not be complete (that is, it is possible that some PRs that have been 11572 fixed are not listed here). 11573 11574 GCC 4.6.2 11575 11576 This is the [20]list of problem reports (PRs) from GCC's bug tracking 11577 system that are known to be fixed in the 4.6.2 release. This list might 11578 not be complete (that is, it is possible that some PRs that have been 11579 fixed are not listed here). 11580 11581 GCC 4.6.3 11582 11583 This is the [21]list of problem reports (PRs) from GCC's bug tracking 11584 system that are known to be fixed in the 4.6.3 release. This list might 11585 not be complete (that is, it is possible that some PRs that have been 11586 fixed are not listed here). 11587 11588 GCC 4.6.4 11589 11590 This is the [22]list of problem reports (PRs) from GCC's bug tracking 11591 system that are known to be fixed in the 4.6.4 release. This list might 11592 not be complete (that is, it is possible that some PRs that have been 11593 fixed are not listed here). 11594 11595 11596 For questions related to the use of GCC, please consult these web 11597 pages and the [23]GCC manuals. If that fails, the 11598 [24]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11599 web pages and the development of GCC are welcome on our developer 11600 list at [25]gcc (a] gcc.gnu.org. All of [26]our lists have public 11601 archives. 11602 11603 Copyright (C) [27]Free Software Foundation, Inc. Verbatim copying and 11604 distribution of this entire article is permitted in any medium, 11605 provided this notice is preserved. 11606 11607 These pages are [28]maintained by the GCC team. Last modified 11608 2023-01-18. 11609 11610 References 11611 11612 1. https://sourceware.org/bugzilla/show_bug.cgi?id=10401 11613 2. http://gcc.gnu.org/gcc-4.5/changes.html 11614 3. http://gcc.gnu.org/gcc-4.5/changes.html#obsoleted 11615 4. http://gcc.gnu.org/gcc-4.6/porting_to.html 11616 5. http://gcc.gnu.org/projects/lto/whopr.pdf 11617 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 11618 7. http://gcc.gnu.org/gcc-4.6/cxx0x_status.html 11619 8. https://gcc.gnu.org/PR43145 11620 9. https://gcc.gnu.org/PR43680 11621 10. https://gcc.gnu.org/PR33558 11622 11. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253 11623 12. https://gcc.gnu.org/onlinedocs/gcc-4.6.4/libstdc++/manual/manual/status.html#status.iso.200x 11624 13. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode.html 11625 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html#debug.races 11626 15. https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html 11627 16. https://gcc.gnu.org/wiki/OOP 11628 17. https://gcc.gnu.org/wiki/Coarray 11629 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcoarray_007d-233 11630 19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.1 11631 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.2 11632 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.3 11633 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.4 11634 23. https://gcc.gnu.org/onlinedocs/ 11635 24. mailto:gcc-help (a] gcc.gnu.org 11636 25. mailto:gcc (a] gcc.gnu.org 11637 26. https://gcc.gnu.org/lists.html 11638 27. https://www.fsf.org/ 11639 28. https://gcc.gnu.org/about.html 11640 ====================================================================== 11641 http://gcc.gnu.org/gcc-4.5/index.html 11642 11643 GCC 4.5 Release Series 11644 11645 (This release series is no longer supported.) 11646 11647 Jul 2, 2012 11648 11649 The [1]GNU project and the GCC developers are pleased to announce the 11650 release of GCC 4.5.4. 11651 11652 This release is a bug-fix release, containing fixes for regressions in 11653 GCC 4.5.3 relative to previous releases of GCC. 11654 11655 Release History 11656 11657 GCC 4.5.4 11658 Jul 2, 2012 ([2]changes) 11659 11660 GCC 4.5.3 11661 Apr 28, 2011 ([3]changes) 11662 11663 GCC 4.5.2 11664 Dec 16, 2010 ([4]changes) 11665 11666 GCC 4.5.1 11667 Jul 31, 2010 ([5]changes) 11668 11669 GCC 4.5.0 11670 April 14, 2010 ([6]changes) 11671 11672 References and Acknowledgements 11673 11674 GCC used to stand for the GNU C Compiler, but since the compiler 11675 supports several other languages aside from C, it now stands for the 11676 GNU Compiler Collection. 11677 11678 A list of [7]successful builds is updated as new information becomes 11679 available. 11680 11681 The GCC developers would like to thank the numerous people that have 11682 contributed new features, improvements, bug fixes, and other changes as 11683 well as test results to GCC. This [8]amazing group of volunteers is 11684 what makes GCC successful. 11685 11686 For additional information about GCC please refer to the [9]GCC project 11687 web site or contact the [10]GCC development mailing list. 11688 11689 To obtain GCC please use [11]our mirror sites or [12]our version 11690 control system. 11691 11692 11693 For questions related to the use of GCC, please consult these web 11694 pages and the [13]GCC manuals. If that fails, the 11695 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11696 web pages and the development of GCC are welcome on our developer 11697 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 11698 archives. 11699 11700 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 11701 distribution of this entire article is permitted in any medium, 11702 provided this notice is preserved. 11703 11704 These pages are [18]maintained by the GCC team. Last modified 11705 2022-10-26. 11706 11707 References 11708 11709 1. http://www.gnu.org/ 11710 2. http://gcc.gnu.org/gcc-4.5/changes.html 11711 3. http://gcc.gnu.org/gcc-4.5/changes.html 11712 4. http://gcc.gnu.org/gcc-4.5/changes.html 11713 5. http://gcc.gnu.org/gcc-4.5/changes.html 11714 6. http://gcc.gnu.org/gcc-4.5/changes.html 11715 7. http://gcc.gnu.org/gcc-4.5/buildstat.html 11716 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 11717 9. http://gcc.gnu.org/index.html 11718 10. mailto:gcc (a] gcc.gnu.org 11719 11. http://gcc.gnu.org/mirrors.html 11720 12. http://gcc.gnu.org/git.html 11721 13. https://gcc.gnu.org/onlinedocs/ 11722 14. mailto:gcc-help (a] gcc.gnu.org 11723 15. mailto:gcc (a] gcc.gnu.org 11724 16. https://gcc.gnu.org/lists.html 11725 17. https://www.fsf.org/ 11726 18. https://gcc.gnu.org/about.html 11727 ====================================================================== 11728 http://gcc.gnu.org/gcc-4.5/changes.html 11729 11730 GCC 4.5 Release Series 11731 Changes, New Features, and Fixes 11732 11733 Caveats 11734 11735 * GCC now requires the [1]MPC library in order to build. See the 11736 [2]prerequisites page for version requirements. 11737 * Support for a number of older systems and recently unmaintained or 11738 untested target ports of GCC has been declared obsolete in GCC 4.5. 11739 Unless there is activity to revive them, the next release of GCC 11740 will have their sources permanently removed. 11741 The following ports for individual systems on particular 11742 architectures have been obsoleted: 11743 + IRIX releases before 6.5 (mips-sgi-irix5*, 11744 mips-sgi-irix6.[0-4]) 11745 + Solaris 7 (*-*-solaris2.7) 11746 + Tru64 UNIX releases before V5.1 (alpha*-dec-osf4*, 11747 alpha-dec-osf5.0*) 11748 + Details for the IRIX, Solaris 7, and Tru64 UNIX obsoletions 11749 can be found in the [3]announcement. 11750 Support for the classic POWER architecture implemented in the 11751 original RIOS and RIOS2 processors of the old IBM RS/6000 product 11752 line has been obsoleted in the rs6000 port. This does not affect 11753 the new generation Power and PowerPC architectures. 11754 * Support has been removed for all the [4]configurations obsoleted in 11755 GCC 4.4. 11756 * Support has been removed for the protoize and unprotoize utilities, 11757 obsoleted in GCC 4.4. 11758 * Support has been removed for tuning for Itanium1 (Merced) variants. 11759 Note that code tuned for Itanium2 should also run correctly on 11760 Itanium1. 11761 * GCC now generates unwind info also for epilogues. DWARF debuginfo 11762 generated by GCC now uses more features of DWARF3 than before, and 11763 also some DWARF4 features. GDB older than 7.0 is not able to handle 11764 either of these, so to debug GCC 4.5 generated binaries or 11765 libraries GDB 7.0 or later is needed. You can disable use of DWARF4 11766 features with the -gdwarf-3 -gstrict-dwarf options, or use 11767 -gdwarf-2 -gstrict-dwarf to restrict GCC to just DWARF2, but 11768 epilogue unwind info is emitted unconditionally whenever unwind 11769 info is emitted. 11770 * On x86 targets, code containing floating-point calculations may run 11771 significantly more slowly when compiled with GCC 4.5 in strict C99 11772 conformance mode than they did with earlier GCC versions. This is 11773 due to stricter standard conformance of the compiler and can be 11774 avoided by using the option -fexcess-precision=fast; also see 11775 [5]below. 11776 * The function attribute noinline no longer prevents GCC from cloning 11777 the function. A new attribute noclone has been introduced for this 11778 purpose. Cloning a function means that it is duplicated and the new 11779 copy is specialized for certain contexts (for example when a 11780 parameter is a known constant). 11781 11782 General Optimizer Improvements 11783 11784 * The -save-temps now takes an optional argument. The -save-temps and 11785 -save-temps=cwd switches write the temporary files in the current 11786 working directory based on the original source file. The 11787 -save-temps=obj switch will write files into the directory 11788 specified with the -o option, and the intermediate filenames are 11789 based on the output file. This will allow the user to get the 11790 compiler intermediate files when doing parallel builds without two 11791 builds of the same filename located in different directories from 11792 interfering with each other. 11793 * Debugging dumps are now created in the same directory as the object 11794 file rather than in the current working directory. This allows the 11795 user to get debugging dumps when doing parallel builds without two 11796 builds of the same filename interfering with each other. 11797 * GCC has been integrated with the MPC library. This allows GCC to 11798 evaluate complex arithmetic at compile time [6]more accurately. It 11799 also allows GCC to evaluate calls to complex built-in math 11800 functions having constant arguments and replace them at compile 11801 time with their mathematically equivalent results. In doing so, GCC 11802 can generate correct results regardless of the math library 11803 implementation or floating point precision of the host platform. 11804 This also allows GCC to generate identical results regardless of 11805 whether one compiles in native or cross-compile configurations to a 11806 particular target. The following built-in functions take advantage 11807 of this new capability: cacos, cacosh, casin, casinh, catan, 11808 catanh, ccos, ccosh, cexp, clog, cpow, csin, csinh, csqrt, ctan, 11809 and ctanh. The float and long double variants of these functions 11810 (e.g. csinf and csinl) are also handled. 11811 * A new link-time optimizer has been added ([7]-flto). When this 11812 option is used, GCC generates a bytecode representation of each 11813 input file and writes it to specially-named sections in each object 11814 file. When the object files are linked together, all the function 11815 bodies are read from these named sections and instantiated as if 11816 they had been part of the same translation unit. This enables 11817 interprocedural optimizations to work across different files (and 11818 even different languages), potentially improving the performance of 11819 the generated code. To use the link-timer optimizer, -flto needs to 11820 be specified at compile time and during the final link. If the 11821 program does not require any symbols to be exported, it is possible 11822 to combine -flto and the experimental [8]-fwhopr with 11823 [9]-fwhole-program to allow the interprocedural optimizers to use 11824 more aggressive assumptions. 11825 * The automatic parallelization pass was enhanced to support 11826 parallelization of outer loops. 11827 * Automatic parallelization can be enabled as part of Graphite. In 11828 addition to -ftree-parallelize-loops=, specify 11829 -floop-parallelize-all to enable the Graphite-based optimization. 11830 * The infrastructure for optimizing based on [10]restrict qualified 11831 pointers has been rewritten and should result in code generation 11832 improvements. Optimizations based on restrict qualified pointers 11833 are now also available when using -fno-strict-aliasing. 11834 * There is a new optimization pass that attempts to change prototype 11835 of functions to avoid unused parameters, pass only relevant parts 11836 of structures and turn arguments passed by reference to arguments 11837 passed by value when possible. It is enabled by -O2 and above as 11838 well as -Os and can be manually invoked using the new command-line 11839 switch -fipa-sra. 11840 * GCC now optimize exception handling code. In particular cleanup 11841 regions that are proved to not have any effect are optimized out. 11842 11843 New Languages and Language specific improvements 11844 11845 All languages 11846 11847 * The -fshow-column option is now on by default. This means error 11848 messages now have a column associated with them. 11849 11850 Ada 11851 11852 * Compilation of programs heavily using discriminated record types 11853 with variant parts has been sped up and generates more compact 11854 code. 11855 * Stack checking now works reasonably well on most plaforms. In some 11856 specific cases, stack overflows may still fail to be detected, but 11857 a compile-time warning will be issued for these cases. 11858 11859 C family 11860 11861 * If a header named in a #include directive is not found, the 11862 compiler exits immediately. This avoids a cascade of errors arising 11863 from declarations expected to be found in that header being 11864 missing. 11865 * A new built-in function __builtin_unreachable() has been added that 11866 tells the compiler that control will never reach that point. It may 11867 be used after asm statements that terminate by transferring control 11868 elsewhere, and in other places that are known to be unreachable. 11869 * The -Wlogical-op option now warns for logical expressions such as 11870 (c == 1 && c == 2) and (c != 1 || c != 2), which are likely to be 11871 mistakes. This option is disabled by default. 11872 * An asm goto feature has been added to allow asm statements that 11873 jump to C labels. 11874 * C++0x raw strings are supported for C++ and for C with -std=gnu99. 11875 * The deprecated attribute now takes an optional string argument, for 11876 example, __attribute__((deprecated("text string"))), that will be 11877 printed together with the deprecation warning. 11878 11879 C 11880 11881 * The -Wenum-compare option, which warns when comparing values of 11882 different enum types, now works for C. It formerly only worked for 11883 C++. This warning is enabled by -Wall. It may be avoided by using a 11884 type cast. 11885 * The -Wcast-qual option now warns about casts which are unsafe in 11886 that they permit const-correctness to be violated without further 11887 warnings. Specifically, it warns about cases where a qualifier is 11888 added when all the lower types are not const. For example, it warns 11889 about a cast from char ** to const char **. 11890 * The -Wc++-compat option is significantly improved. It issues new 11891 warnings for: 11892 + Using C++ reserved operator names as identifiers. 11893 + Conversions to enum types without explicit casts. 11894 + Using va_arg with an enum type. 11895 + Using different enum types in the two branches of ?:. 11896 + Using ++ or -- on a variable of enum type. 11897 + Using the same name as both a struct, union or enum tag and a 11898 typedef, unless the typedef refers to the tagged type itself. 11899 + Using a struct, union, or enum which is defined within another 11900 struct or union. 11901 + A struct field defined using a typedef if there is a field in 11902 the struct, or an enclosing struct, whose name is the typedef 11903 name. 11904 + Duplicate definitions at file scope. 11905 + Uninitialized const variables. 11906 + A global variable with an anonymous struct, union, or enum 11907 type. 11908 + Using a string constant to initialize a char array whose size 11909 is the length of the string. 11910 * The new -Wjump-misses-init option warns about cases where a goto or 11911 switch skips the initialization of a variable. This sort of branch 11912 is an error in C++ but not in C. This warning is enabled by 11913 -Wc++-compat. 11914 * GCC now ensures that a C99-conforming <stdint.h> is present on most 11915 targets, and uses information about the types in this header to 11916 implement the Fortran bindings to those types. GCC does not ensure 11917 the presence of such a header, and does not implement the Fortran 11918 bindings, on the following targets: NetBSD, VxWorks, VMS, 11919 SymbianOS, WinCE, LynxOS, Netware, QNX, Interix, TPF. 11920 * GCC now implements C90- and C99-conforming rules for constant 11921 expressions. This may cause warnings or errors for some code using 11922 expressions that can be folded to a constant but are not constant 11923 expressions as defined by ISO C. 11924 * All known target-independent C90 and C90 Amendment 1 conformance 11925 bugs, and all known target-independent C99 conformance bugs not 11926 related to floating point or extended identifiers, have been fixed. 11927 * The C decimal floating point support now includes support for the 11928 FLOAT_CONST_DECIMAL64 pragma. 11929 * The named address space feature from ISO/IEC TR 18037 is now 11930 supported. This is currently only implemented for the SPU 11931 processor. 11932 11933 C++ 11934 11935 * Improved [11]experimental support for the upcoming C++0x ISO C++ 11936 standard, including support for raw strings, lambda expressions and 11937 explicit type conversion operators. 11938 * When printing the name of a class template specialization, G++ will 11939 now omit any template arguments which come from default template 11940 arguments. This behavior (and the pretty-printing of function 11941 template specializations as template signature and arguments) can 11942 be disabled with the -fno-pretty-templates option. 11943 * Access control is now applied to typedef names used in a template, 11944 which may cause G++ to reject some ill-formed code that was 11945 accepted by earlier releases. The -fno-access-control option can be 11946 used as a temporary workaround until the code is corrected. 11947 * Compilation time for code that uses templates should now scale 11948 linearly with the number of instantiations rather than 11949 quadratically, as template instantiations are now looked up using 11950 hash tables. 11951 * Declarations of functions that look like builtin declarations of 11952 library functions are only considered to be redeclarations if they 11953 are declared with extern "C". This may cause problems with code 11954 that omits extern "C" on hand-written declarations of C library 11955 functions such as abort or memcpy. Such code is ill-formed, but was 11956 accepted by earlier releases. 11957 * Diagnostics that used to complain about passing non-POD types to 11958 ... or jumping past the declaration of a non-POD variable now check 11959 for triviality rather than PODness, as per C++0x. 11960 * In C++0x mode local and anonymous classes are now allowed as 11961 template arguments, and in declarations of variables and functions 11962 with linkage, so long as any such declaration that is used is also 11963 defined ([12]DR 757). 11964 * Labels may now have attributes, as has been permitted for a while 11965 in C. This is only permitted when the label definition and the 11966 attribute specifier is followed by a semicolon--i.e., the label 11967 applies to an empty statement. The only useful attribute for a 11968 label is unused. 11969 * G++ now implements [13]DR 176. Previously G++ did not support using 11970 the injected-class-name of a template base class as a type name, 11971 and lookup of the name found the declaration of the template in the 11972 enclosing scope. Now lookup of the name finds the 11973 injected-class-name, which can be used either as a type or as a 11974 template, depending on whether or not the name is followed by a 11975 template argument list. As a result of this change, some code that 11976 was previously accepted may be ill-formed because 11977 1. The injected-class-name is not accessible because it's from a 11978 private base, or 11979 2. The injected-class-name cannot be used as an argument for a 11980 template template parameter. 11981 In either of these cases, the code can be fixed by adding a 11982 nested-name-specifier to explicitly name the template. The first 11983 can be worked around with -fno-access-control; the second is only 11984 rejected with -pedantic. 11985 * A new standard mangling for SIMD vector types has been added, to 11986 avoid name clashes on systems with vectors of varying length. By 11987 default the compiler still uses the old mangling, but emits aliases 11988 with the new mangling on targets that support strong aliases. Users 11989 can switch over entirely to the new mangling with -fabi-version=4 11990 or -fabi-version=0. -Wabi will now warn about code that uses the 11991 old mangling. 11992 * The command-line option -ftemplate-depth-N is now written as 11993 -ftemplate-depth=N and the old form is deprecated. 11994 * Conversions between NULL and non-pointer types are now warned by 11995 default. The new option -Wno-conversion-null disables these 11996 warnings. Previously these warnings were only available when using 11997 -Wconversion explicitly. 11998 11999 Runtime Library (libstdc++) 12000 12001 * Improved experimental support for the upcoming ISO C++ standard, 12002 C++0x, including: 12003 + Support for <future>, <functional>, and <random>. 12004 + Existing facilities now exploit explicit operators and the 12005 newly implemented core C++0x features. 12006 + The header <cstdatomic> has been renamed to <atomic>. 12007 * An experimental [14]profile mode has been added. This is an 12008 implementation of many C++ standard library constructs with an 12009 additional analysis layer that gives performance improvement advice 12010 based on recognition of suboptimal usage patterns. For example, 12011 #include <vector> 12012 int main() 12013 { 12014 std::vector<int> v; 12015 for (int k = 0; k < 1024; ++k) 12016 v.insert(v.begin(), k); 12017 } 12018 12019 When instrumented via the profile mode, can return suggestions 12020 about the initial size and choice of the container used as follows: 12021 vector-to-list: improvement = 5: call stack = 0x804842c ... 12022 : advice = change std::vector to std::list 12023 vector-size: improvement = 3: call stack = 0x804842c ... 12024 : advice = change initial container size from 0 to 1024 12025 12026 These constructs can be substituted for the normal libstdc++ 12027 constructs on a piecemeal basis, or all existing components can be 12028 transformed via the -D_GLIBCXX_PROFILE macro. 12029 * [15]Support for decimal floating-point arithmetic (aka ISO C++ TR 12030 24733) has been added. This support is in header file 12031 <decimal/decimal>, uses namespace std::decimal, and includes 12032 classes decimal32, decimal64, and decimal128. 12033 * Sources have been audited for application of function attributes 12034 nothrow, const, pure, and noreturn. 12035 * Python pretty-printers have been added for many standard library 12036 components that simplify the internal representation and present a 12037 more intuitive view of components when used with 12038 appropriately-advanced versions of GDB. For more information, 12039 please consult the more [16]detailed description. 12040 * The default behavior for comparing typeinfo names has changed, so 12041 in <typeinfo>, __GXX_MERGED_TYPEINFO_NAMES now defaults to zero. 12042 * The new -static-libstdc++ option directs g++ to link the C++ 12043 library statically, even if the default would normally be to link 12044 it dynamically. 12045 12046 Fortran 12047 12048 * The COMMON default padding has been changed - instead of adding the 12049 padding before a variable it is now added afterwards, which 12050 increases the compatibility with other vendors and helps to obtain 12051 the correct output in some cases. Cf. also the -falign-commons 12052 option ([17]added in 4.4). 12053 * The -finit-real= option now also supports the value snan for 12054 signaling not-a-number; to be effective, one additionally needs to 12055 enable trapping (e.g. via -ffpe-trap=). Note: Compile-time 12056 optimizations can turn a signaling NaN into a quiet one. 12057 * The new option -fcheck= has been added with the options bounds, 12058 array-temps, do, pointer, and recursive. The bounds and array-temps 12059 options are equivalent to -fbounds-check and 12060 -fcheck-array-temporaries. The do option checks for invalid 12061 modification of loop iteration variables, and the recursive option 12062 tests for recursive calls to subroutines/functions which are not 12063 marked as recursive. With pointer pointer association checks in 12064 calls are performed; however, neither undefined pointers nor 12065 pointers in expressions are handled. Using -fcheck=all enables all 12066 these run-time checks. 12067 * The run-time checking -fcheck=bounds now warns about invalid string 12068 lengths of character dummy arguments. Additionally, more 12069 compile-time checks have been added. 12070 * The new option [18]-fno-protect-parens has been added; if set, the 12071 compiler may reorder REAL and COMPLEX expressions without regard to 12072 parentheses. 12073 * GNU Fortran no longer links against libgfortranbegin. As before, 12074 MAIN__ (assembler symbol name) is the actual Fortran main program, 12075 which is invoked by the main function. However, main is now 12076 generated and put in the same object file as MAIN__. For the time 12077 being, libgfortranbegin still exists for backward compatibility. 12078 For details see the new [19]Mixed-Language Programming chapter in 12079 the manual. 12080 * The I/O library was restructured for performance and cleaner code. 12081 * Array assignments and WHERE are now run in parallel when OpenMP's 12082 WORKSHARE is used. 12083 * The experimental option -fwhole-file was added. The option allows 12084 whole-file checking of procedure arguments and allows for better 12085 optimizations. It can also be used with -fwhole-program, which is 12086 now also supported in gfortran. 12087 * More Fortran 2003 and Fortran 2008 mathematical functions can now 12088 be used as initialization expressions. 12089 * Some extended attributes such as STDCALL are now supported via the 12090 [20]GCC$ compiler directive. 12091 * For Fortran 77 compatibility: If -fno-sign-zero is used, the SIGN 12092 intrinsic behaves now as if zero were always positive. 12093 * For legacy compatibiliy: On Cygwin and MinGW, the special files 12094 CONOUT$ and CONIN$ (and CONERR$ which maps to CONOUT$) are now 12095 supported. 12096 * Fortran 2003 support has been extended: 12097 + Procedure-pointer function results and procedure-pointer 12098 components (including PASS), 12099 + allocatable scalars (experimental), 12100 + DEFERRED type-bound procedures, 12101 + the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements 12102 have been implemented. 12103 + The ALLOCATE statement supports type-specs and the SOURCE= 12104 argument. 12105 + OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC 12106 type-bound procedure (i.e. as type-bound operators). 12107 + Rounding (ROUND=, RZ, ...) for output is now supported. 12108 + The INT_FAST{8,16,32,64,128}_T kind type parameters of the 12109 intrinsic module ISO_C_BINDING are now supported, except for 12110 the targets listed above as ones where GCC does not have 12111 <stdint.h> type information. 12112 + Extensible derived types with type-bound procedure or 12113 procedure pointer with PASS attribute now have to use CLASS in 12114 line with the Fortran 2003 standard; the workaround to use 12115 TYPE is no longer supported. 12116 + [21]Experimental, incomplete support for polymorphism, 12117 including CLASS, SELECT TYPE and dynamic dispatch of 12118 type-bound procedure calls. Some features do not work yet such 12119 as unlimited polymorphism (CLASS(*)). 12120 * Fortran 2008 support has been extended: 12121 + The OPEN statement now supports the NEWUNIT= option, which 12122 returns a unique file unit, thus preventing inadvertent use of 12123 the same unit in different parts of the program. 12124 + Support for unlimited format items has been added. 12125 + The INT{8,16,32} and REAL{32,64,128} kind type parameters of 12126 the intrinsic module ISO_FORTRAN_ENV are now supported. 12127 + Using complex arguments with TAN, SINH, COSH, TANH, ASIN, 12128 ACOS, and ATAN is now possible; the functions ASINH, ACOSH, 12129 and ATANH have been added (for real and complex arguments) and 12130 ATAN(Y,X) is now an alias for ATAN2(Y,X). 12131 + The BLOCK construct has been implemented. 12132 12133 New Targets and Target Specific Improvements 12134 12135 AIX 12136 12137 * Full cross-toolchain support now available with GNU Binutils 12138 12139 ARM 12140 12141 * GCC now supports the Cortex-M0 and Cortex-A5 processors. 12142 * GCC now supports the ARM v7E-M architecture. 12143 * GCC now supports VFPv4-based FPUs and FPUs with 12144 single-precision-only VFP. 12145 * GCC has many improvements to optimization for other ARM processors, 12146 including scheduling support for the integer pipeline on Cortex-A9. 12147 * GCC now supports the IEEE 754-2008 half-precision floating-point 12148 type, and a variant ARM-specific half-precision type. This type is 12149 specified using __fp16, with the layout determined by 12150 -mfp16-format. With appropriate -mfpu options, the Cortex-A9 and 12151 VFPv4 half-precision instructions will be used. 12152 * GCC now supports the variant of AAPCS that uses VFP registers for 12153 parameter passing and return values. 12154 12155 AVR 12156 12157 * The -mno-tablejump option has been removed because it has the same 12158 effect as the -fno-jump-tables option. 12159 * Added support for these new AVR devices: 12160 + ATmega8U2 12161 + ATmega16U2 12162 + ATmega32U2 12163 12164 IA-32/x86-64 12165 12166 * GCC now will set the default for -march= based on the configure 12167 target. 12168 * GCC now supports handling floating-point excess precision arising 12169 from use of the x87 floating-point unit in a way that conforms to 12170 ISO C99. This is enabled with -fexcess-precision=standard and with 12171 standards conformance options such as -std=c99, and may be disabled 12172 using -fexcess-precision=fast. 12173 * Support for the Intel Atom processor is now available through the 12174 -march=atom and -mtune=atom options. 12175 * A new -mcrc32 option is now available to enable crc32 intrinsics. 12176 * A new -mmovbe option is now available to enable GCC to use the 12177 movbe instruction to implement __builtin_bswap32 and 12178 __builtin_bswap64. 12179 * SSE math now can be enabled by default at configure time with the 12180 new --with-fpmath=sse option. 12181 * There is a new intrinsic header file, <x86intrin.h>. It should be 12182 included before using any IA-32/x86-64 intrinsics. 12183 * Support for the XOP, FMA4, and LWP instruction sets for the AMD 12184 Orochi processors are now available with the -mxop, -mfma4, and 12185 -mlwp options. 12186 * The -mabm option enables GCC to use the popcnt and lzcnt 12187 instructions on AMD processors. 12188 * The -mpopcnt option enables GCC to use the popcnt instructions on 12189 both AMD and Intel processors. 12190 12191 M68K/ColdFire 12192 12193 * GCC now supports ColdFire 51xx, 5221x, 5225x, 52274, 52277, 5301x 12194 and 5441x devices. 12195 * GCC now supports thread-local storage (TLS) on M68K and ColdFire 12196 processors. 12197 12198 MeP 12199 12200 Support has been added for the Toshiba Media embedded Processor (MeP, 12201 or mep-elf) embedded target. 12202 12203 MIPS 12204 12205 * GCC now supports MIPS 1004K processors. 12206 * GCC can now be configured with options --with-arch-32, 12207 --with-arch-64, --with-tune-32 and --with-tune-64 to control the 12208 default optimization separately for 32-bit and 64-bit modes. 12209 * MIPS targets now support an alternative _mcount interface, in which 12210 register $12 points to the function's save slot for register $31. 12211 This interface is selected by the -mcount-ra-address option; see 12212 the documentation for more details. 12213 * GNU/Linux targets can now generate read-only .eh_frame sections. 12214 This optimization requires GNU binutils 2.20 or above, and is only 12215 available if GCC is configured with a suitable version of binutils. 12216 * GNU/Linux targets can now attach special relocations to indirect 12217 calls, so that the linker can turn them into direct jumps or 12218 branches. This optimization requires GNU binutils 2.20 or later, 12219 and is automatically selected if GCC is configured with an 12220 appropriate version of binutils. It can be explicitly enabled or 12221 disabled using the -mrelax-pic-calls command-line option. 12222 * GCC now generates more heavily-optimized atomic operations on 12223 Octeon processors. 12224 * MIPS targets now support the -fstack-protector option. 12225 * GCC now supports an -msynci option, which specifies that synci is 12226 enough to flush the instruction cache, without help from the 12227 operating system. GCC uses this information to optimize 12228 automatically-generated cache flush operations, such as those used 12229 for nested functions in C. There is also a --with-synci 12230 configure-time option, which makes -msynci the default. 12231 * GCC supports four new function attributes for interrupt handlers: 12232 interrupt, use_shadow_register_set, keep_interrupts_masked and 12233 use_debug_exception_return. See the documentation for more details 12234 about these attributes. 12235 12236 RS/6000 (POWER/PowerPC) 12237 12238 * GCC now supports the Power ISA 2.06, which includes the VSX 12239 instructions that add vector 64-bit floating point support, new 12240 population count instructions, and conversions between floating 12241 point and unsigned types. 12242 * Support for the power7 processor is now available through the 12243 -mcpu=power7 and -mtune=power7. 12244 * GCC will now vectorize loops that contain simple math functions 12245 like copysign when generating code for altivec or VSX targets. 12246 * Support for the A2 processor is now available through the -mcpu=a2 12247 and -mtune=a2 options. 12248 * Support for the 476 processor is now available through the 12249 -mcpu={476,476fp} and -mtune={476,476fp} options. 12250 * Support for the e500mc64 processor is now available through the 12251 -mcpu=e500mc64 and -mtune=e500mc64 options. 12252 * GCC can now be configured with options --with-cpu-32, 12253 --with-cpu-64, --with-tune-32 and --with-tune-64 to control the 12254 default optimization separately for 32-bit and 64-bit modes. 12255 * Starting with GCC 4.5.4, vectors of type vector long long or vector 12256 long are passed and returned in the same method as other vectors 12257 with the VSX instruction set. Previously the GCC compiler did not 12258 adhere to the ABI for 128-bit vectors with 64-bit integer base 12259 types (PR 48857). This is also fixed in the GCC 4.6.1 release. 12260 12261 RX 12262 12263 Support has been added for the Renesas RX Processor (rx-elf) target. 12264 12265 Operating Systems 12266 12267 Windows (Cygwin and MinGW) 12268 12269 * GCC now installs all the major language runtime libraries as DLLs 12270 when configured with the --enable-shared option. 12271 * GCC now makes use of the new support for aligned common variables 12272 in versions of binutils >= 2.20 to fix bugs in the support for SSE 12273 data types. 12274 * Improvements to the libffi support library increase the reliability 12275 of code generated by GCJ on all Windows platforms. Libgcj is 12276 enabled by default for the first time. 12277 * Libtool improvements simplify installation by placing the generated 12278 DLLs in the correct binaries directory. 12279 * Numerous other minor bugfixes and improvements, and substantial 12280 enhancements to the Fortran language support library. 12281 12282 > 12283 12284 Other significant improvements 12285 12286 Plugins 12287 12288 * It is now possible to extend the compiler without having to modify 12289 its source code. A new option -fplugin=file.so tells GCC to load 12290 the shared object file.so and execute it as part of the compiler. 12291 The internal documentation describes the details on how plugins can 12292 interact with the compiler. 12293 12294 Installation changes 12295 12296 * The move to newer autotools changed default installation 12297 directories and switches to control them: The --with-datarootdir, 12298 --with-docdir, --with-pdfdir, and --with-htmldir switches are not 12299 used any more. Instead, you can now use --datarootdir, --docdir, 12300 --htmldir, and --pdfdir. The default installation directories have 12301 changed as follows according to the GNU Coding Standards: 12302 12303 datarootdir read-only architecture-independent data root [PREFIX/share] 12304 localedir locale-specific message catalogs [DATAROOTDIR/locale] 12305 docdir documentation root [DATAROOTDIR/doc/PACKAGE] 12306 htmldir html documentation [DOCDIR] 12307 dvidir dvi documentation [DOCDIR] 12308 pdfdir pdf documentation [DOCDIR] 12309 psdir ps documentation [DOCDIR] 12310 The following variables have new default values: 12311 12312 datadir read-only architecture-independent data [DATAROOTDIR] 12313 infodir info documentation [DATAROOTDIR/info] 12314 mandir man documentation [DATAROOTDIR/man] 12315 12316 GCC 4.5.1 12317 12318 This is the [22]list of problem reports (PRs) from GCC's bug tracking 12319 system that are known to be fixed in the 4.5.1 release. This list might 12320 not be complete (that is, it is possible that some PRs that have been 12321 fixed are not listed here). 12322 12323 All languages 12324 12325 * GCC's new link-time optimizer ([23]-flto) now also works on a few 12326 non-ELF targets: 12327 + Cygwin (*-cygwin*) 12328 + MinGW (*-mingw*) 12329 + Darwin on x86-64 (x86_64-apple-darwin*) 12330 LTO is not enabled by default for these targets. To enable LTO, you 12331 should configure with the --enable-lto option. 12332 12333 GCC 4.5.2 12334 12335 This is the [24]list of problem reports (PRs) from GCC's bug tracking 12336 system that are known to be fixed in the 4.5.2 release. This list might 12337 not be complete (that is, it is possible that some PRs that have been 12338 fixed are not listed here). 12339 12340 GCC 4.5.3 12341 12342 This is the [25]list of problem reports (PRs) from GCC's bug tracking 12343 system that are known to be fixed in the 4.5.3 release. This list might 12344 not be complete (that is, it is possible that some PRs that have been 12345 fixed are not listed here). 12346 12347 On the PowerPC compiler, the Altivec builtin functions vec_ld and 12348 vec_st have been modified to generate the Altivec memory instructions 12349 LVX and STVX, even if the -mvsx option is used. In the initial GCC 4.5 12350 release, these builtin functions were changed to generate VSX memory 12351 reference instructions instead of Altivec memory instructions, but 12352 there are differences between the two instructions. If the VSX 12353 instruction set is available, you can now use the new builtin functions 12354 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 12355 instructions. 12356 12357 GCC 4.5.4 12358 12359 This is the [26]list of problem reports (PRs) from GCC's bug tracking 12360 system that are known to be fixed in the 4.5.4 release. This list might 12361 not be complete (that is, it is possible that some PRs that have been 12362 fixed are not listed here). 12363 12364 12365 For questions related to the use of GCC, please consult these web 12366 pages and the [27]GCC manuals. If that fails, the 12367 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12368 web pages and the development of GCC are welcome on our developer 12369 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 12370 archives. 12371 12372 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 12373 distribution of this entire article is permitted in any medium, 12374 provided this notice is preserved. 12375 12376 These pages are [32]maintained by the GCC team. Last modified 12377 2023-01-15. 12378 12379 References 12380 12381 1. https://www.multiprecision.org/mpc/ 12382 2. https://gcc.gnu.org/install/prerequisites.html 12383 3. https://gcc.gnu.org/ml/gcc/2010-01/msg00510.html 12384 4. http://gcc.gnu.org/gcc-4.4/changes.html#obsoleted 12385 5. http://gcc.gnu.org/gcc-4.5/changes.html#x86 12386 6. https://gcc.gnu.org/PR30789 12387 7. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 12388 8. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhopr-802 12389 9. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhole-program-800 12390 10. https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html 12391 11. http://gcc.gnu.org/gcc-4.5/cxx0x_status.html 12392 12. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#757 12393 13. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#176 12394 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/profile_mode.html 12395 15. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.tr24733 12396 16. https://sourceware.org/gdb/wiki/STLSupport 12397 17. http://gcc.gnu.org/gcc-4.4/changes.html 12398 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 12399 19. https://gcc.gnu.org/onlinedocs/gfortran/Mixed-Language-Programming.html 12400 20. https://gcc.gnu.org/onlinedocs/gfortran/GNU-Fortran-Compiler-Directives.html 12401 21. https://gcc.gnu.org/wiki/OOP 12402 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.1 12403 23. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 12404 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.2 12405 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.3 12406 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.4 12407 27. https://gcc.gnu.org/onlinedocs/ 12408 28. mailto:gcc-help (a] gcc.gnu.org 12409 29. mailto:gcc (a] gcc.gnu.org 12410 30. https://gcc.gnu.org/lists.html 12411 31. https://www.fsf.org/ 12412 32. https://gcc.gnu.org/about.html 12413 ====================================================================== 12414 http://gcc.gnu.org/gcc-4.4/index.html 12415 12416 GCC 4.4 Release Series 12417 12418 This release series is no longer maintained. 12419 12420 March 13, 2012 12421 12422 The [1]GNU project and the GCC developers are pleased to announce the 12423 release of GCC 4.4.7. 12424 12425 This release is a bug-fix release, containing fixes for regressions in 12426 GCC 4.4.6 relative to previous releases of GCC. 12427 12428 Release History 12429 12430 GCC 4.4.7 12431 March 13, 2012 ([2]changes) 12432 12433 GCC 4.4.6 12434 April 16, 2011 ([3]changes) 12435 12436 GCC 4.4.5 12437 October 1, 2010 ([4]changes) 12438 12439 GCC 4.4.4 12440 April 29, 2010 ([5]changes) 12441 12442 GCC 4.4.3 12443 January 21, 2010 ([6]changes) 12444 12445 GCC 4.4.2 12446 October 15, 2009 ([7]changes) 12447 12448 GCC 4.4.1 12449 July 22, 2009 ([8]changes) 12450 12451 GCC 4.4.0 12452 April 21, 2009 ([9]changes) 12453 12454 References and Acknowledgements 12455 12456 GCC used to stand for the GNU C Compiler, but since the compiler 12457 supports several other languages aside from C, it now stands for the 12458 GNU Compiler Collection. 12459 12460 A list of [10]successful builds is updated as new information becomes 12461 available. 12462 12463 The GCC developers would like to thank the numerous people that have 12464 contributed new features, improvements, bug fixes, and other changes as 12465 well as test results to GCC. This [11]amazing group of volunteers is 12466 what makes GCC successful. 12467 12468 For additional information about GCC please refer to the [12]GCC 12469 project web site or contact the [13]GCC development mailing list. 12470 12471 To obtain GCC please use [14]our mirror sites or [15]our version 12472 control system. 12473 12474 12475 For questions related to the use of GCC, please consult these web 12476 pages and the [16]GCC manuals. If that fails, the 12477 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12478 web pages and the development of GCC are welcome on our developer 12479 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 12480 archives. 12481 12482 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 12483 distribution of this entire article is permitted in any medium, 12484 provided this notice is preserved. 12485 12486 These pages are [21]maintained by the GCC team. Last modified 12487 2022-10-26. 12488 12489 References 12490 12491 1. http://www.gnu.org/ 12492 2. http://gcc.gnu.org/gcc-4.4/changes.html 12493 3. http://gcc.gnu.org/gcc-4.4/changes.html 12494 4. http://gcc.gnu.org/gcc-4.4/changes.html 12495 5. http://gcc.gnu.org/gcc-4.4/changes.html 12496 6. http://gcc.gnu.org/gcc-4.4/changes.html 12497 7. http://gcc.gnu.org/gcc-4.4/changes.html 12498 8. http://gcc.gnu.org/gcc-4.4/changes.html 12499 9. http://gcc.gnu.org/gcc-4.4/changes.html 12500 10. http://gcc.gnu.org/gcc-4.4/buildstat.html 12501 11. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 12502 12. http://gcc.gnu.org/index.html 12503 13. mailto:gcc (a] gcc.gnu.org 12504 14. http://gcc.gnu.org/mirrors.html 12505 15. http://gcc.gnu.org/git.html 12506 16. https://gcc.gnu.org/onlinedocs/ 12507 17. mailto:gcc-help (a] gcc.gnu.org 12508 18. mailto:gcc (a] gcc.gnu.org 12509 19. https://gcc.gnu.org/lists.html 12510 20. https://www.fsf.org/ 12511 21. https://gcc.gnu.org/about.html 12512 ====================================================================== 12513 http://gcc.gnu.org/gcc-4.4/changes.html 12514 12515 GCC 4.4 Release Series 12516 Changes, New Features, and Fixes 12517 12518 The latest release in the 4.4 release series is [1]GCC 4.4.7. 12519 12520 Caveats 12521 12522 * __builtin_stdarg_start has been completely removed from GCC. 12523 Support for <varargs.h> had been deprecated since GCC 4.0. Use 12524 __builtin_va_start as a replacement. 12525 * Some of the errors issued by the C++ front end that could be 12526 downgraded to warnings in previous releases by using -fpermissive 12527 are now warnings by default. They can be converted into errors by 12528 using -pedantic-errors. 12529 * Use of the cpp assertion extension will now emit a warning when 12530 -Wdeprecated or -pedantic is used. This extension has been 12531 deprecated for many years, but never warned about. 12532 * Packed bit-fields of type char were not properly bit-packed on many 12533 targets prior to GCC 4.4. On these targets, the fix in GCC 4.4 12534 causes an ABI change. For example there is no longer a 4-bit 12535 padding between field a and b in this structure: 12536 struct foo 12537 { 12538 char a:4; 12539 char b:8; 12540 } __attribute__ ((packed)); 12541 There is a new warning to help identify fields that are affected: 12542 foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4 12543 The warning can be disabled with -Wno-packed-bitfield-compat. 12544 * On ARM EABI targets, the C++ mangling of the va_list type has been 12545 changed to conform to the current revision of the EABI. This does 12546 not affect the libstdc++ library included with GCC. 12547 * The SCOUNT and POS bits of the MIPS DSP control register are now 12548 treated as global. Previous versions of GCC treated these fields as 12549 call-clobbered instead. 12550 * The MIPS port no longer recognizes the h asm constraint. It was 12551 necessary to remove this constraint in order to avoid generating 12552 unpredictable code sequences. 12553 One of the main uses of the h constraint was to extract the high 12554 part of a multiplication on 64-bit targets. For example: 12555 asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y)); 12556 You can now achieve the same effect using 128-bit types: 12557 typedef unsigned int uint128_t __attribute__((mode(TI))); 12558 result = ((uint128_t) x * y) >> 64; 12559 The second sequence is better in many ways. For example, if x and y 12560 are constants, the compiler can perform the multiplication at 12561 compile time. If x and y are not constants, the compiler can 12562 schedule the runtime multiplication better than it can schedule an 12563 asm statement. 12564 * Support for a number of older systems and recently unmaintained or 12565 untested target ports of GCC has been declared obsolete in GCC 4.4. 12566 Unless there is activity to revive them, the next release of GCC 12567 will have their sources permanently removed. 12568 The following ports for individual systems on particular 12569 architectures have been obsoleted: 12570 + Generic a.out on IA32 and m68k (i[34567]86-*-aout*, 12571 m68k-*-aout*) 12572 + Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*, 12573 armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*, 12574 sh-*-*). This does not affect other more specific targets 12575 using the COFF object format on those architectures, or the 12576 more specific H8300 and SH targets (h8300-*-rtems*, 12577 h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*, 12578 sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks). 12579 + 2BSD on PDP-11 (pdp11-*-bsd) 12580 + AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*, 12581 powerpc-ibm-aix4.[12]*) 12582 + Tuning support for Itanium1 (Merced) variants. Note that code 12583 tuned for Itanium2 should also run correctly on Itanium1. 12584 * The protoize and unprotoize utilities have been obsoleted and will 12585 be removed in GCC 4.5. These utilities have not been installed by 12586 default since GCC 3.0. 12587 * Support has been removed for all the [2]configurations obsoleted in 12588 GCC 4.3. 12589 * Unknown -Wno-* options are now silently ignored by GCC if no other 12590 diagnostics are issued. If other diagnostics are issued, then GCC 12591 warns about the unknown options. 12592 * More information on porting to GCC 4.4 from previous versions of 12593 GCC can be found in the [3]porting guide for this release. 12594 12595 General Optimizer Improvements 12596 12597 * A new command-line switch -findirect-inlining has been added. When 12598 turned on it allows the inliner to also inline indirect calls that 12599 are discovered to have known targets at compile time thanks to 12600 previous inlining. 12601 * A new command-line switch -ftree-switch-conversion has been added. 12602 This new pass turns simple initializations of scalar variables in 12603 switch statements into initializations from a static array, given 12604 that all the values are known at compile time and the ratio between 12605 the new array size and the original switch branches does not exceed 12606 the parameter --param switch-conversion-max-branch-ratio (default 12607 is eight). 12608 * A new command-line switch -ftree-builtin-call-dce has been added. 12609 This optimization eliminates unnecessary calls to certain builtin 12610 functions when the return value is not used, in cases where the 12611 calls can not be eliminated entirely because the function may set 12612 errno. This optimization is on by default at -O2 and above. 12613 * A new command-line switch -fconserve-stack directs the compiler to 12614 minimize stack usage even if it makes the generated code slower. 12615 This affects inlining decisions. 12616 * When the assembler supports it, the compiler will now emit unwind 12617 information using assembler .cfi directives. This makes it possible 12618 to use such directives in inline assembler code. The new option 12619 -fno-dwarf2-cfi-asm directs the compiler to not use .cfi 12620 directives. 12621 * The [4]Graphite branch has been merged. This merge has brought in a 12622 new framework for loop optimizations based on a polyhedral 12623 intermediate representation. These optimizations apply to all the 12624 languages supported by GCC. The following new code transformations 12625 are available in GCC 4.4: 12626 + -floop-interchange performs loop interchange transformations 12627 on loops. Interchanging two nested loops switches the inner 12628 and outer loops. For example, given a loop like: 12629 DO J = 1, M 12630 DO I = 1, N 12631 A(J, I) = A(J, I) * C 12632 ENDDO 12633 ENDDO 12634 12635 loop interchange will transform the loop as if the user had 12636 written: 12637 DO I = 1, N 12638 DO J = 1, M 12639 A(J, I) = A(J, I) * C 12640 ENDDO 12641 ENDDO 12642 12643 which can be beneficial when N is larger than the caches, 12644 because in Fortran, the elements of an array are stored in 12645 memory contiguously by column, and the original loop iterates 12646 over rows, potentially creating at each access a cache miss. 12647 + -floop-strip-mine performs loop strip mining transformations 12648 on loops. Strip mining splits a loop into two nested loops. 12649 The outer loop has strides equal to the strip size and the 12650 inner loop has strides of the original loop within a strip. 12651 For example, given a loop like: 12652 DO I = 1, N 12653 A(I) = A(I) + C 12654 ENDDO 12655 12656 loop strip mining will transform the loop as if the user had 12657 written: 12658 DO II = 1, N, 4 12659 DO I = II, min (II + 3, N) 12660 A(I) = A(I) + C 12661 ENDDO 12662 ENDDO 12663 12664 + -floop-block performs loop blocking transformations on loops. 12665 Blocking strip mines each loop in the loop nest such that the 12666 memory accesses of the element loops fit inside caches. For 12667 example, given a loop like: 12668 DO I = 1, N 12669 DO J = 1, M 12670 A(J, I) = B(I) + C(J) 12671 ENDDO 12672 ENDDO 12673 12674 loop blocking will transform the loop as if the user had 12675 written: 12676 DO II = 1, N, 64 12677 DO JJ = 1, M, 64 12678 DO I = II, min (II + 63, N) 12679 DO J = JJ, min (JJ + 63, M) 12680 A(J, I) = B(I) + C(J) 12681 ENDDO 12682 ENDDO 12683 ENDDO 12684 ENDDO 12685 12686 which can be beneficial when M is larger than the caches, 12687 because the innermost loop will iterate over a smaller amount 12688 of data that can be kept in the caches. 12689 * A new register allocator has replaced the old one. It is called 12690 integrated register allocator (IRA) because coalescing, register 12691 live range splitting, and hard register preferencing are done 12692 on-the-fly during coloring. It also has better integration with the 12693 reload pass. IRA is a regional register allocator which uses modern 12694 Chaitin-Briggs coloring instead of Chow's priority coloring used in 12695 the old register allocator. More info about IRA internals and 12696 options can be found in the GCC manuals. 12697 * A new instruction scheduler and software pipeliner, based on the 12698 selective scheduling approach, has been added. The new pass 12699 performs instruction unification, register renaming, substitution 12700 through register copies, and speculation during scheduling. The 12701 software pipeliner is able to pipeline non-countable loops. The new 12702 pass is targeted at scheduling-eager in-order platforms. In GCC 4.4 12703 it is available for the Intel Itanium platform working by default 12704 as the second scheduling pass (after register allocation) at the 12705 -O3 optimization level. 12706 * When using -fprofile-generate with a multi-threaded program, the 12707 profile counts may be slightly wrong due to race conditions. The 12708 new -fprofile-correction option directs the compiler to apply 12709 heuristics to smooth out the inconsistencies. By default the 12710 compiler will give an error message when it finds an inconsistent 12711 profile. 12712 * The new -fprofile-dir=PATH option permits setting the directory 12713 where profile data files are stored when using -fprofile-generate 12714 and friends, and the directory used when reading profile data files 12715 using -fprofile-use and friends. 12716 12717 New warning options 12718 12719 * The new -Wframe-larger-than=NUMBER option directs GCC to emit a 12720 warning if any stack frame is larger than NUMBER bytes. This may be 12721 used to help ensure that code fits within a limited amount of stack 12722 space. 12723 * The command-line option -Wlarger-than-N is now written as 12724 -Wlarger-than=N and the old form is deprecated. 12725 * The new -Wno-mudflap option disables warnings about constructs 12726 which can not be instrumented when using -fmudflap. 12727 12728 New Languages and Language specific improvements 12729 12730 * Version 3.0 of the OpenMP specification is now supported for the C, 12731 C++, and Fortran compilers. 12732 * New character data types, per [5]TR 19769: New character types in 12733 C, are now supported for the C compiler in -std=gnu99 mode, as 12734 __CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in 12735 -std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too. 12736 12737 C family 12738 12739 * A new optimize attribute was added to allow programmers to change 12740 the optimization level and particular optimization options for an 12741 individual function. You can also change the optimization options 12742 via the GCC optimize pragma for functions defined after the pragma. 12743 The GCC push_options pragma and the GCC pop_options pragma allow 12744 you temporarily save and restore the options used. The GCC 12745 reset_options pragma restores the options to what was specified on 12746 the command line. 12747 * Uninitialized warnings do not require enabling optimization 12748 anymore, that is, -Wuninitialized can be used together with -O0. 12749 Nonetheless, the warnings given by -Wuninitialized will probably be 12750 more accurate if optimization is enabled. 12751 * -Wparentheses now warns about expressions such as (!x | y) and (!x 12752 & y). Using explicit parentheses, such as in ((!x) | y), silences 12753 this warning. 12754 * -Wsequence-point now warns within if, while,do while and for 12755 conditions, and within for begin/end expressions. 12756 * A new option -dU is available to dump definitions of preprocessor 12757 macros that are tested or expanded. 12758 12759 C++ 12760 12761 * [6]Improved experimental support for the upcoming ISO C++ standard, 12762 C++0x. Including support for auto, inline namespaces, generalized 12763 initializer lists, defaulted and deleted functions, new character 12764 types, and scoped enums. 12765 * Those errors that may be downgraded to warnings to build legacy 12766 code now mention -fpermissive when -fdiagnostics-show-option is 12767 enabled. 12768 * -Wconversion now warns if the result of a static_cast to enumeral 12769 type is unspecified because the value is outside the range of the 12770 enumeral type. 12771 * -Wuninitialized now warns if a non-static reference or non-static 12772 const member appears in a class without constructors. 12773 * G++ now properly implements value-initialization, so objects with 12774 an initializer of () and an implicitly defined default constructor 12775 will be zero-initialized before the default constructor is called. 12776 12777 Runtime Library (libstdc++) 12778 12779 * Improved experimental support for the upcoming ISO C++ standard, 12780 C++0x, including: 12781 + Support for <chrono>, <condition_variable>, <cstdatomic>, 12782 <forward_list>, <initializer_list>, <mutex>, <ratio>, 12783 <system_error>, and <thread>. 12784 + unique_ptr, <algorithm> additions, exception propagation, and 12785 support for the new character types in <string> and <limits>. 12786 + Existing facilities now exploit initializer lists, defaulted 12787 and deleted functions, and the newly implemented core C++0x 12788 features. 12789 + Some standard containers are more efficient together with 12790 stateful allocators, i.e., no allocator is constructed on the 12791 fly at element construction time. 12792 * Experimental support for non-standard pointer types in containers. 12793 * The long standing libstdc++/30928 has been fixed for targets 12794 running glibc 2.10 or later. 12795 * As usual, many small and larger bug fixes, in particular quite a 12796 few corner cases in <locale>. 12797 12798 Fortran 12799 12800 * GNU Fortran now employs libcpp directly instead of using cc1 as an 12801 external preprocessor. The [7]-cpp option was added to allow manual 12802 invocation of the preprocessor without relying on filename 12803 extensions. 12804 * The [8]-Warray-temporaries option warns about array temporaries 12805 generated by the compiler, as an aid to optimization. 12806 * The [9]-fcheck-array-temporaries option has been added, printing a 12807 notification at run time, when an array temporary had to be created 12808 for an function argument. Contrary to -Warray-temporaries the 12809 warning is only printed if the array is noncontiguous. 12810 * Improved generation of DWARF debugging symbols 12811 * If using an intrinsic not part of the selected standard (via -std= 12812 and -fall-intrinsics) gfortran will now treat it as if this 12813 procedure were declared EXTERNAL and try to link to a user-supplied 12814 procedure. -Wintrinsics-std will warn whenever this happens. The 12815 now-useless option -Wnonstd-intrinsic was removed. 12816 * The flag -falign-commons has been added to control the alignment of 12817 variables in COMMON blocks, which is enabled by default in line 12818 with previous GCC version. Using -fno-align-commons one can force 12819 commons to be contiguous in memory as required by the Fortran 12820 standard, however, this slows down the memory access. The option 12821 -Walign-commons, which is enabled by default, warns when padding 12822 bytes were added for alignment. The proper solution is to sort the 12823 common objects by decreasing storage size, which avoids the 12824 alignment problems. 12825 * Fortran 2003 support has been extended: 12826 + Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is 12827 now supported (except internal reads from/writes to wide 12828 strings). [10]-fbackslash now supports also \unnnn and 12829 \Unnnnnnnn to enter Unicode characters. 12830 + Asynchronous I/O (implemented as synchronous I/O) and the 12831 decimal=, size=, sign=, pad=, blank=, and delim= specifiers 12832 are now supported in I/O statements. 12833 + Support for Fortran 2003 structure constructors and for array 12834 constructor with typespec has been added. 12835 + Procedure Pointers (but not yet as component in derived types 12836 and as function results) are now supported. 12837 + Abstract types, type extension, and type-bound procedures 12838 (both PROCEDURE and GENERIC but not as operators). Note: As 12839 CLASS/polymorphyic types are not implemented, type-bound 12840 procedures with PASS accept as non-standard extension TYPE 12841 arguments. 12842 * Fortran 2008 support has been added: 12843 + The -std=f2008 option and support for the file extensions 12844 .f2008 and .F2008 has been added. 12845 + The g0 format descriptor is now supported. 12846 + The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH, 12847 ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED 12848 are now available (some of them existed as GNU extension 12849 before). Note: The hyperbolic functions are not yet supporting 12850 complex arguments and the three- argument version of BESSEL_*N 12851 is not available. 12852 + The bit intrinsics LEADZ and TRAILZ have been added. 12853 12854 Java (GCJ) 12855 12856 Ada 12857 12858 * The Ada runtime now supports multilibs on many platforms including 12859 x86_64, SPARC and PowerPC. Their build is enabled by default. 12860 12861 New Targets and Target Specific Improvements 12862 12863 ARM 12864 12865 * GCC now supports optimizing for the Cortex-A9, Cortex-R4 and 12866 Cortex-R4F processors and has many other improvements to 12867 optimization for ARM processors. 12868 * GCC now supports the VFPv3 variant with 16 double-precision 12869 registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been 12870 renamed to -mfpu=vfpv3. 12871 * GCC now supports the -mfix-cortex-m3-ldrd option to work around an 12872 erratum on Cortex-M3 processors. 12873 * GCC now supports the __sync_* atomic operations for ARM EABI 12874 GNU/Linux. 12875 * The section anchors optimization is now enabled by default when 12876 optimizing for ARM. 12877 * GCC now uses a new EABI-compatible profiling interface for EABI 12878 targets. This requires a function __gnu_mcount_nc, which is 12879 provided by GNU libc versions 2.8 and later. 12880 12881 AVR 12882 12883 * The -mno-tablejump option has been deprecated because it has the 12884 same effect as the -fno-jump-tables option. 12885 * Added support for these new AVR devices: 12886 + ATA6289 12887 + ATtiny13A 12888 + ATtiny87 12889 + ATtiny167 12890 + ATtiny327 12891 + ATmega8C1 12892 + ATmega16C1 12893 + ATmega32C1 12894 + ATmega8M1 12895 + ATmega16M1 12896 + ATmega32M1 12897 + ATmega32U4 12898 + ATmega16HVB 12899 + ATmega4HVD 12900 + ATmega8HVD 12901 + ATmega64C1 12902 + ATmega64M1 12903 + ATmega16U4 12904 + ATmega32U6 12905 + ATmega128RFA1 12906 + AT90PWM81 12907 + AT90SCR100 12908 + M3000F 12909 + M3000S 12910 + M3001B 12911 12912 IA-32/x86-64 12913 12914 * Support for Intel AES built-in functions and code generation is 12915 available via -maes. 12916 * Support for Intel PCLMUL built-in function and code generation is 12917 available via -mpclmul. 12918 * Support for Intel AVX built-in functions and code generation is 12919 available via -mavx. 12920 * Automatically align the stack for local variables with alignment 12921 requirement. 12922 * GCC can now utilize the SVML library for vectorizing calls to a set 12923 of C99 functions if -mveclibabi=svml is specified and you link to 12924 an SVML ABI compatible library. 12925 * On x86-64, the ABI has been changed in the following cases to 12926 conform to the x86-64 ABI: 12927 + Passing/returning structures with flexible array member: 12928 struct foo 12929 { 12930 int i; 12931 int flex[]; 12932 }; 12933 + Passing/returning structures with complex float member: 12934 struct foo 12935 { 12936 int i; 12937 __complex__ float f; 12938 }; 12939 + Passing/returning unions with long double member: 12940 union foo 12941 { 12942 int x; 12943 long double ld; 12944 }; 12945 Code built with previous versions of GCC that uses any of these is 12946 not compatible with code built with GCC 4.4.0 or later. 12947 * A new target attribute was added to allow programmers to change the 12948 target options like -msse2 or -march=k8 for an individual function. 12949 You can also change the target options via the GCC target pragma 12950 for functions defined after the pragma. 12951 * GCC can now be configured with options --with-arch-32, 12952 --with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and 12953 --with-tune-64 to control the default optimization separately for 12954 32-bit and 64-bit modes. 12955 12956 IA-32/IA64 12957 12958 * Support for __float128 (TFmode) IEEE quad type and corresponding 12959 TCmode IEEE complex quad type is available via the soft-fp library 12960 on IA-32/IA64 targets. This includes basic arithmetic operations 12961 (addition, subtraction, negation, multiplication and division) on 12962 __float128 real and TCmode complex values, the full set of IEEE 12963 comparisons between __float128 values, conversions to and from 12964 float, double and long double floating point types, as well as 12965 conversions to and from signed or unsigned integer, signed or 12966 unsigned long integer and signed or unsigned quad (TImode, IA64 12967 only) integer types. Additionally, all operations generate the full 12968 set of IEEE exceptions and support the full set of IEEE rounding 12969 modes. 12970 12971 M68K/ColdFire 12972 12973 * GCC now supports instruction scheduling for ColdFire V1, V3 and V4 12974 processors. (Scheduling support for ColdFire V2 processors was 12975 added in GCC 4.3.) 12976 * GCC now supports the -mxgot option to support programs requiring 12977 many GOT entries on ColdFire. 12978 * The m68k-*-linux-gnu target now builds multilibs by default. 12979 12980 MIPS 12981 12982 * MIPS Technologies have extended the original MIPS SVR4 ABI to 12983 include support for procedure linkage tables (PLTs) and copy 12984 relocations. These extensions allow GNU/Linux executables to use a 12985 significantly more efficient code model than the one defined by the 12986 original ABI. 12987 GCC support for this code model is available via a new command-line 12988 option, -mplt. There is also a new configure-time option, 12989 --with-mips-plt, to make -mplt the default. 12990 The new code model requires support from the assembler, the linker, 12991 and the runtime C library. This support is available in binutils 12992 2.19 and GLIBC 2.9. 12993 * GCC can now generate MIPS16 code for 32-bit GNU/Linux executables 12994 and 32-bit GNU/Linux shared libraries. This feature requires GNU 12995 binutils 2.19 or above. 12996 * Support for RMI's XLR processor is now available through the 12997 -march=xlr and -mtune=xlr options. 12998 * 64-bit targets can now perform 128-bit multiplications inline, 12999 instead of relying on a libgcc function. 13000 * Native GNU/Linux toolchains now support -march=native and 13001 -mtune=native, which select the host processor. 13002 * GCC now supports the R10K, R12K, R14K and R16K processors. The 13003 canonical -march= and -mtune= names for these processors are 13004 r10000, r12000, r14000 and r16000 respectively. 13005 * GCC can now work around the side effects of speculative execution 13006 on R10K processors. Please see the documentation of the 13007 -mr10k-cache-barrier option for details. 13008 * Support for the MIPS64 Release 2 instruction set has been added. 13009 The option -march=mips64r2 enables generation of these 13010 instructions. 13011 * GCC now supports Cavium Networks' Octeon processor. This support is 13012 available through the -march=octeon and -mtune=octeon options. 13013 * GCC now supports STMicroelectronics' Loongson 2E/2F processors. The 13014 canonical -march= and -mtune= names for these processors are 13015 loongson2e and loongson2f. 13016 13017 picochip 13018 13019 Picochip is a 16-bit processor. A typical picoChip contains over 250 13020 small cores, each with small amounts of memory. There are three 13021 processor variants (STAN, MEM and CTRL) with different instruction sets 13022 and memory configurations and they can be chosen using the -mae option. 13023 13024 This port is intended to be a "C" only port. 13025 13026 Power Architecture and PowerPC 13027 13028 * GCC now supports the e300c2, e300c3 and e500mc processors. 13029 * GCC now supports Xilinx processors with a single-precision FPU. 13030 * Decimal floating point is now supported for e500 processors. 13031 13032 S/390, zSeries and System z9/z10 13033 13034 * Support for the IBM System z10 EC/BC processor has been added. When 13035 using the -march=z10 option, the compiler will generate code making 13036 use of instructions provided by the General-Instruction-Extension 13037 Facility and the Execute-Extension Facility. 13038 13039 VxWorks 13040 13041 * GCC now supports the thread-local storage mechanism used on 13042 VxWorks. 13043 13044 Xtensa 13045 13046 * GCC now supports thread-local storage (TLS) for Xtensa processor 13047 configurations that include the Thread Pointer option. TLS also 13048 requires support from the assembler and linker; this support is 13049 provided in the GNU binutils beginning with version 2.19. 13050 13051 Documentation improvements 13052 13053 Other significant improvements 13054 13055 GCC 4.4.1 13056 13057 This is the [11]list of problem reports (PRs) from GCC's bug tracking 13058 system that are known to be fixed in the 4.4.1 release. This list might 13059 not be complete (that is, it is possible that some PRs that have been 13060 fixed are not listed here). 13061 13062 GCC 4.4.2 13063 13064 This is the [12]list of problem reports (PRs) from GCC's bug tracking 13065 system that are known to be fixed in the 4.4.2 release. This list might 13066 not be complete (that is, it is possible that some PRs that have been 13067 fixed are not listed here). 13068 13069 GCC 4.4.3 13070 13071 This is the [13]list of problem reports (PRs) from GCC's bug tracking 13072 system that are known to be fixed in the 4.4.3 release. This list might 13073 not be complete (that is, it is possible that some PRs that have been 13074 fixed are not listed here). 13075 13076 GCC 4.4.4 13077 13078 This is the [14]list of problem reports (PRs) from GCC's bug tracking 13079 system that are known to be fixed in the 4.4.4 release. This list might 13080 not be complete (that is, it is possible that some PRs that have been 13081 fixed are not listed here). 13082 13083 GCC 4.4.5 13084 13085 This is the [15]list of problem reports (PRs) from GCC's bug tracking 13086 system that are known to be fixed in the 4.4.5 release. This list might 13087 not be complete (that is, it is possible that some PRs that have been 13088 fixed are not listed here). 13089 13090 GCC 4.4.6 13091 13092 This is the [16]list of problem reports (PRs) from GCC's bug tracking 13093 system that are known to be fixed in the 4.4.6 release. This list might 13094 not be complete (that is, it is possible that some PRs that have been 13095 fixed are not listed here). 13096 13097 GCC 4.4.7 13098 13099 This is the [17]list of problem reports (PRs) from GCC's bug tracking 13100 system that are known to be fixed in the 4.4.7 release. This list might 13101 not be complete (that is, it is possible that some PRs that have been 13102 fixed are not listed here). 13103 13104 13105 For questions related to the use of GCC, please consult these web 13106 pages and the [18]GCC manuals. If that fails, the 13107 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13108 web pages and the development of GCC are welcome on our developer 13109 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 13110 archives. 13111 13112 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 13113 distribution of this entire article is permitted in any medium, 13114 provided this notice is preserved. 13115 13116 These pages are [23]maintained by the GCC team. Last modified 13117 2022-11-01. 13118 13119 References 13120 13121 1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.7 13122 2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted 13123 3. http://gcc.gnu.org/gcc-4.4/porting_to.html 13124 4. https://gcc.gnu.org/wiki/Graphite 13125 5. https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf 13126 6. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html 13127 7. https://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html 13128 8. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125 13129 9. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221 13130 10. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34 13131 11. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1 13132 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2 13133 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3 13134 14. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4 13135 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.5 13136 16. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.6 13137 17. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.7 13138 18. https://gcc.gnu.org/onlinedocs/ 13139 19. mailto:gcc-help (a] gcc.gnu.org 13140 20. mailto:gcc (a] gcc.gnu.org 13141 21. https://gcc.gnu.org/lists.html 13142 22. https://www.fsf.org/ 13143 23. https://gcc.gnu.org/about.html 13144 ====================================================================== 13145 http://gcc.gnu.org/gcc-4.3/index.html 13146 13147 GCC 4.3 Release Series 13148 13149 (This release series is no longer supported.) 13150 13151 Jun 27, 2011 13152 13153 The [1]GNU project and the GCC developers are pleased to announce the 13154 release of GCC 4.3.6. 13155 13156 This release is a bug-fix release, containing fixes for regressions in 13157 GCC 4.3.5 relative to previous releases of GCC. 13158 13159 Release History 13160 13161 GCC 4.3.6 13162 Jun 27, 2011 ([2]changes) 13163 13164 GCC 4.3.5 13165 May 22, 2010 ([3]changes) 13166 13167 GCC 4.3.4 13168 August 4, 2009 ([4]changes) 13169 13170 GCC 4.3.3 13171 January 24, 2009 ([5]changes) 13172 13173 GCC 4.3.2 13174 August 27, 2008 ([6]changes) 13175 13176 GCC 4.3.1 13177 June 6, 2008 ([7]changes) 13178 13179 GCC 4.3.0 13180 March 5, 2008 ([8]changes) 13181 13182 References and Acknowledgements 13183 13184 GCC used to stand for the GNU C Compiler, but since the compiler 13185 supports several other languages aside from C, it now stands for the 13186 GNU Compiler Collection. 13187 13188 A list of [9]successful builds is updated as new information becomes 13189 available. 13190 13191 The GCC developers would like to thank the numerous people that have 13192 contributed new features, improvements, bug fixes, and other changes as 13193 well as test results to GCC. This [10]amazing group of volunteers is 13194 what makes GCC successful. 13195 13196 For additional information about GCC please refer to the [11]GCC 13197 project web site or contact the [12]GCC development mailing list. 13198 13199 To obtain GCC please use [13]our mirror sites or [14]our version 13200 control system. 13201 13202 13203 For questions related to the use of GCC, please consult these web 13204 pages and the [15]GCC manuals. If that fails, the 13205 [16]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13206 web pages and the development of GCC are welcome on our developer 13207 list at [17]gcc (a] gcc.gnu.org. All of [18]our lists have public 13208 archives. 13209 13210 Copyright (C) [19]Free Software Foundation, Inc. Verbatim copying and 13211 distribution of this entire article is permitted in any medium, 13212 provided this notice is preserved. 13213 13214 These pages are [20]maintained by the GCC team. Last modified 13215 2022-10-26. 13216 13217 References 13218 13219 1. http://www.gnu.org/ 13220 2. http://gcc.gnu.org/gcc-4.3/changes.html 13221 3. http://gcc.gnu.org/gcc-4.3/changes.html 13222 4. http://gcc.gnu.org/gcc-4.3/changes.html 13223 5. http://gcc.gnu.org/gcc-4.3/changes.html 13224 6. http://gcc.gnu.org/gcc-4.3/changes.html 13225 7. http://gcc.gnu.org/gcc-4.3/changes.html 13226 8. http://gcc.gnu.org/gcc-4.3/changes.html 13227 9. http://gcc.gnu.org/gcc-4.3/buildstat.html 13228 10. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13229 11. http://gcc.gnu.org/index.html 13230 12. mailto:gcc (a] gcc.gnu.org 13231 13. http://gcc.gnu.org/mirrors.html 13232 14. http://gcc.gnu.org/git.html 13233 15. https://gcc.gnu.org/onlinedocs/ 13234 16. mailto:gcc-help (a] gcc.gnu.org 13235 17. mailto:gcc (a] gcc.gnu.org 13236 18. https://gcc.gnu.org/lists.html 13237 19. https://www.fsf.org/ 13238 20. https://gcc.gnu.org/about.html 13239 ====================================================================== 13240 http://gcc.gnu.org/gcc-4.3/changes.html 13241 13242 GCC 4.3 Release Series 13243 Changes, New Features, and Fixes 13244 13245 The latest release in the 4.3 release series is [1]GCC 4.3.5. 13246 13247 Caveats 13248 13249 * GCC requires the [2]GMP and [3]MPFR libraries for building all the 13250 various front-end languages it supports. See the [4]prerequisites 13251 page for version requirements. 13252 * ColdFire targets now treat long double as having the same format as 13253 double. In earlier versions of GCC, they used the 68881 long double 13254 format instead. 13255 * The m68k-uclinux target now uses the same calling conventions as 13256 m68k-linux-gnu. You can select the original calling conventions by 13257 configuring for m68k-uclinuxoldabi instead. Note that 13258 m68k-uclinuxoldabi also retains the original 80-bit long double on 13259 ColdFire targets. 13260 * The -fforce-mem option has been removed because it has had no 13261 effect in the last few GCC releases. 13262 * The i386 -msvr3-shlib option has been removed since it is no longer 13263 used. 13264 * Fastcall for i386 has been changed not to pass aggregate arguments 13265 in registers, following Microsoft compilers. 13266 * Support for the AOF assembler has been removed from the ARM back 13267 end; this affects only the targets arm-semi-aof and armel-semi-aof, 13268 which are no longer recognized. We removed these targets without a 13269 deprecation period because we discovered that they have been 13270 unusable since GCC 4.0.0. 13271 * Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*) 13272 has been removed. This support had been deprecated since GCC 4.0.0. 13273 * Support for a number of older systems and recently unmaintained or 13274 untested target ports of GCC has been declared obsolete in GCC 4.3. 13275 Unless there is activity to revive them, the next release of GCC 13276 will have their sources permanently removed. 13277 All GCC ports for the following processor architectures have been 13278 declared obsolete: 13279 + Morpho MT (mt-*) 13280 The following aliases for processor architectures have been 13281 declared obsolete. Users should use the indicated generic target 13282 names instead, with compile-time options such as -mcpu or 13283 configure-time options such as --with-cpu to control the 13284 configuration more precisely. 13285 + strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-* 13286 instead). 13287 + parisc*-*-* (use hppa*-*-* instead). 13288 + m680[012]0-*-* (use m68k-*-* instead). 13289 All GCC ports for the following operating systems have been 13290 declared obsolete: 13291 + BeOS (*-*-beos*) 13292 + kaOS (*-*-kaos*) 13293 + GNU/Linux using the a.out object format (*-*-linux*aout*) 13294 + GNU/Linux using version 1 of the GNU C Library 13295 (*-*-linux*libc1*) 13296 + Solaris versions before Solaris 7 (*-*-solaris2.[0-6], 13297 *-*-solaris2.[0-6].*) 13298 + Miscellaneous System V (*-*-sysv*) 13299 + WindISS (*-*-windiss*) 13300 Also, those for some individual systems on particular architectures 13301 have been obsoleted: 13302 + UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*) 13303 + CRIS with a.out object format (cris-*-aout) 13304 + BSD 4.3 on PA-RISC (hppa1.1-*-bsd*) 13305 + OSF/1 on PA-RISC (hppa1.1-*-osf*) 13306 + PRO on PA-RISC (hppa1.1-*-pro*) 13307 + Sequent PTX on IA32 (i[34567]86-sequent-ptx4*, 13308 i[34567]86-sequent-sysv4*) 13309 + SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*) 13310 + UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host 13311 was previously [5]removed in 2001, leaving only the support 13312 for UWIN as a target now being deprecated) 13313 + ChorusOS on PowerPC (powerpc-*-chorusos*) 13314 + All VAX configurations apart from NetBSD and OpenBSD 13315 (vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*) 13316 * The [6]-Wconversion option has been modified. Its purpose now is to 13317 warn for implicit conversions that may alter a value. This new 13318 behavior is available for both C and C++. Warnings about 13319 conversions between signed and unsigned integers can be disabled by 13320 using -Wno-sign-conversion. In C++, they are disabled by default 13321 unless -Wsign-conversion is explicitly requested. The old behavior 13322 of -Wconversion, that is, warn for prototypes causing a type 13323 conversion that is different from what would happen to the same 13324 argument in the absence of a prototype, has been moved to a new 13325 option -Wtraditional-conversion, which is only available for C. 13326 * The -m386, -m486, -mpentium and -mpentiumpro tuning options have 13327 been removed because they were deprecated for more than 3 GCC major 13328 releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or 13329 -mtune=pentiumpro as a replacement. 13330 * The -funsafe-math-optimizations option now automatically turns on 13331 -fno-trapping-math in addition to -fno-signed-zeros, as it enables 13332 reassociation and thus may introduce or remove traps. 13333 * The -ftree-vectorize option is now on by default under -O3. In 13334 order to generate code for a SIMD extension, it has to be enabled 13335 as well: use -maltivec for PowerPC platforms and -msse/-msse2 for 13336 i?86 and x86_64. 13337 * More information on porting to GCC 4.3 from previous versions of 13338 GCC can be found in the [7]porting guide for this release. 13339 13340 General Optimizer Improvements 13341 13342 * The GCC middle-end has been integrated with the MPFR library. This 13343 allows GCC to evaluate and replace at compile-time calls to 13344 built-in math functions having constant arguments with their 13345 mathematically equivalent results. In making use of MPFR, GCC can 13346 generate correct results regardless of the math library 13347 implementation or floating point precision of the host platform. 13348 This also allows GCC to generate identical results regardless of 13349 whether one compiles in native or cross-compile configurations to a 13350 particular target. The following built-in functions take advantage 13351 of this new capability: acos, acosh, asin, asinh, atan2, atan, 13352 atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1, 13353 fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10, 13354 log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh, 13355 tan, tanh, tgamma, y0, y1 and yn. The float and long double 13356 variants of these functions (e.g. sinf and sinl) are also handled. 13357 The sqrt and cabs functions with constant arguments were already 13358 optimized in prior GCC releases. Now they also use MPFR. 13359 * A new forward propagation pass on RTL was added. The new pass 13360 replaces several slower transformations, resulting in compile-time 13361 improvements as well as better code generation in some cases. 13362 * A new command-line switch -frecord-gcc-switches has been added to 13363 GCC, although it is only enabled for some targets. The switch 13364 causes the command line that was used to invoke the compiler to be 13365 recorded into the object file that is being created. The exact 13366 format of this recording is target and binary file format 13367 dependent, but it usually takes the form of a note section 13368 containing ASCII text. The switch is related to the -fverbose-asm 13369 switch, but that one only records the information in the assembler 13370 output file as comments, so the information never reaches the 13371 object file. 13372 * The inliner heuristic is now aware of stack frame consumption. New 13373 command-line parameters --param large-stack-frame and --param 13374 large-stack-frame-growth can be used to limit stack frame size 13375 growth caused by inlining. 13376 * During feedback directed optimizations, the expected block size the 13377 memcpy, memset and bzero functions operate on is discovered and for 13378 cases of commonly used small sizes, specialized inline code is 13379 generated. 13380 * __builtin_expect no longer requires its argument to be a compile 13381 time constant. 13382 * Interprocedural optimization was reorganized to work on functions 13383 in SSA form. This enables more precise and cheaper dataflow 13384 analysis and makes writing interprocedural optimizations easier. 13385 The following improvements have been implemented on top of this 13386 framework: 13387 + Pre-inline optimization: Selected local optimization passes 13388 are run before the inliner (and other interprocedural passes) 13389 are executed. This significantly improves the accuracy of code 13390 growth estimates used by the inliner and reduces the overall 13391 memory footprint for large compilation units. 13392 + Early inlining (a simple bottom-up inliner pass inlining only 13393 functions whose body is smaller than the expected call 13394 overhead) is now executed with the early optimization passes, 13395 thus inlining already optimized function bodies into an 13396 unoptimized function that is subsequently optimized by early 13397 optimizers. This enables the compiler to quickly eliminate 13398 abstraction penalty in C++ programs. 13399 + Interprocedural constant propagation now operate on SSA form 13400 increasing accuracy of the analysis. 13401 * A new internal representation for GIMPLE statements has been 13402 contributed, resulting in compile-time memory savings. 13403 * The vectorizer was enhanced to support vectorization of outer 13404 loops, intra-iteration parallelism (loop-aware SLP), vectorization 13405 of strided accesses and loops with multiple data-types. Run-time 13406 dependency testing using loop versioning was added. The cost model, 13407 turned on by -fvect-cost-model, was developed. 13408 13409 New Languages and Language specific improvements 13410 13411 * We have added new command-line options 13412 -finstrument-functions-exclude-function-list and 13413 -finstrument-functions-exclude-file-list. They provide more control 13414 over which functions are annotated by the -finstrument-functions 13415 option. 13416 13417 C family 13418 13419 * Implicit conversions between generic vector types are now only 13420 permitted when the two vectors in question have the same number of 13421 elements and compatible element types. (Note that the restriction 13422 involves compatible element types, not implicitly-convertible 13423 element types: thus, a vector type with element type int may not be 13424 implicitly converted to a vector type with element type unsigned 13425 int.) This restriction, which is in line with specifications for 13426 SIMD architectures such as AltiVec, may be relaxed using the flag 13427 -flax-vector-conversions. This flag is intended only as a 13428 compatibility measure and should not be used for new code. 13429 * -Warray-bounds has been added and is now enabled by default for 13430 -Wall . It produces warnings for array subscripts that can be 13431 determined at compile time to be always out of bounds. 13432 -Wno-array-bounds will disable the warning. 13433 * The constructor and destructor function attributes now accept 13434 optional priority arguments which control the order in which the 13435 constructor and destructor functions are run. 13436 * New [8]command-line options -Wtype-limits, -Wold-style-declaration, 13437 -Wmissing-parameter-type, -Wempty-body, -Wclobbered and 13438 -Wignored-qualifiers have been added for finer control of the 13439 diverse warnings enabled by -Wextra. 13440 * A new function attribute alloc_size has been added to mark up 13441 malloc style functions. For constant sized allocations this can be 13442 used to find out the size of the returned pointer using the 13443 __builtin_object_size() function for buffer overflow checking and 13444 similar. This supplements the already built-in malloc and calloc 13445 constant size handling. 13446 * Integer constants written in binary are now supported as a GCC 13447 extension. They consist of a prefix 0b or 0B, followed by a 13448 sequence of 0 and 1 digits. 13449 * A new predefined macro __COUNTER__ has been added. It expands to 13450 sequential integral values starting from 0. In conjunction with the 13451 ## operator, this provides a convenient means to generate unique 13452 identifiers. 13453 * A new command-line option -fdirectives-only has been added. It 13454 enables a special preprocessing mode which improves the performance 13455 of applications like distcc and ccache. 13456 * Fixed-point data types and operators have been added. They are 13457 based on Chapter 4 of the Embedded-C specification (n1169.pdf). 13458 Currently, only MIPS targets are supported. 13459 * Decimal floating-point arithmetic based on draft ISO/IEC TR 24732, 13460 N1241, is now supported as a GCC extension to C for targets 13461 i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu, 13462 and x86_64-*-linux-gnu. The feature introduces new data types 13463 _Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF, 13464 DD, and DL. 13465 13466 C++ 13467 13468 * [9]Experimental support for the upcoming ISO C++ standard, C++0x. 13469 * -Wc++0x-compat has been added and is now enabled by default for 13470 -Wall. It produces warnings for constructs whose meaning differs 13471 between ISO C++ 1998 and C++0x. 13472 * The -Wparentheses option now works for C++ as it does for C. It 13473 warns if parentheses are omitted when operators with confusing 13474 precedence are nested. It also warns about ambiguous else 13475 statements. Since -Wparentheses is enabled by -Wall, this may cause 13476 additional warnings with existing C++ code which uses -Wall. These 13477 new warnings may be disabled by using -Wall -Wno-parentheses. 13478 * The -Wmissing-declarations now works for C++ as it does for C. 13479 * The -fvisibility-ms-compat flag was added, to make it easier to 13480 port larger projects using shared libraries from Microsoft's Visual 13481 Studio to ELF and Mach-O systems. 13482 * C++ attribute handling has been overhauled for template arguments 13483 (ie dependent types). In particular, __attribute__((aligned(T))); 13484 works for C++ types. 13485 13486 Runtime Library (libstdc++) 13487 13488 * [10]Experimental support for the upcoming ISO C++ standard, C++0x. 13489 * Support for TR1 mathematical special functions and regular 13490 expressions. 13491 * Default what implementations give more elaborate exception strings 13492 for bad_cast, bad_typeid, bad_exception, and bad_alloc. 13493 * Header dependencies have been streamlined, reducing unnecessary 13494 includes and pre-processed bloat. 13495 * Variadic template implementations of items in <tuple> and 13496 <functional>. 13497 * An experimental [11]parallel mode has been added. This is a 13498 parallel implementation of many C++ Standard library algorithms, 13499 like std::accumulate, std::for_each, std::transform, or std::sort, 13500 to give but four examples. These algorithms can be substituted for 13501 the normal (sequential) libstdc++ algorithms on a piecemeal basis, 13502 or all existing algorithms can be transformed via the 13503 -D_GLIBCXX_PARALLEL macro. 13504 * Debug mode versions of classes in <unordered_set> and 13505 <unordered_map>. 13506 * Formal deprecation of <ext/hash_set> and <ext/hash_map>, which are 13507 now <backward/hash_set> and <backward/hash_map>. This code: 13508 #include <ext/hash_set> 13509 __gnu_cxx::hash_set<int> s; 13510 13511 Can be transformed (in order of preference) to: 13512 #include <tr1/unordered_set> 13513 std::tr1::unordered_set<int> s; 13514 13515 or 13516 #include <backward/hash_set> 13517 __gnu_cxx::hash_set<int> s; 13518 13519 Similar transformations apply to __gnu_cxx::hash_map, 13520 __gnu_cxx::hash_multimap, __gnu_cxx::hash_set, 13521 __gnu_cxx::hash_multiset. 13522 13523 Fortran 13524 13525 * Due to the fact that the GMP and MPFR libraries are required for 13526 all languages, Fortran is no longer special in this regard and is 13527 available by default. 13528 * The [12]-fexternal-blas option has been added, which generates 13529 calls to BLAS routines for intrinsic matrix operations such as 13530 matmul rather than using the built-in algorithms. 13531 * Support to give a backtrace (compiler flag -fbacktrace or 13532 environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems 13533 only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a 13534 run-time error occured. 13535 * GNU Fortran now defines __GFORTRAN__ when it runs the C 13536 preprocessor (CPP). 13537 * The [13]-finit-local-zero, -finit-real, -finit-integer, 13538 -finit-character, and -finit-logical options have been added, which 13539 can be used to initialize local variables. 13540 * The intrinsic procedures [14]GAMMA and [15]LGAMMA have been added, 13541 which calculate the Gamma function and its logarithm. Use EXTERNAL 13542 gamma if you want to use your own gamma function. 13543 * GNU Fortran now regards the backslash character as literal (as 13544 required by the Fortran 2003 standard); using [16]-fbackslash GNU 13545 Fortran interprets backslashes as C-style escape characters. 13546 * The [17]interpretation of binary, octal and hexadecimal (BOZ) 13547 literal constants has been changed. Before they were always 13548 interpreted as integer; now they are bit-wise transferred as 13549 argument of INT, REAL, DBLE and CMPLX as required by the Fortran 13550 2003 standard, and for real and complex variables in DATA 13551 statements or when directly assigned to real and complex variables. 13552 Everywhere else and especially in expressions they are still 13553 regarded as integer constants. 13554 * Fortran 2003 support has been extended: 13555 + Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE 13556 + Pointer intent 13557 + Intrinsic module ISO_ENV_FORTRAN 13558 + Interoperability with C (ISO C Bindings) 13559 + ABSTRACT INTERFACES and PROCEDURE statements (without POINTER 13560 attribute) 13561 + Fortran 2003 BOZ 13562 13563 Java (GCJ) 13564 13565 * GCJ now uses the Eclipse Java compiler for its Java parsing needs. 13566 This enables the use of all 1.5 language features, and fixes most 13567 existing front end bugs. 13568 * libgcj now supports all 1.5 language features which require runtime 13569 support: foreach, enum, annotations, generics, and auto-boxing. 13570 * We've made many changes to the tools shipped with gcj. 13571 + The old jv-scan tool has been removed. This tool never really 13572 worked properly. There is no replacement. 13573 + gcjh has been rewritten. Some of its more obscure options no 13574 longer work, but are still recognized in an attempt at 13575 compatibility. gjavah is a new program with similar 13576 functionality but different command-line options. 13577 + grmic and grmiregistry have been rewritten. grmid has been 13578 added. 13579 + gjar replaces the old fastjar. 13580 + gjarsigner (used for signing jars), gkeytool (used for key 13581 management), gorbd (for CORBA), gserialver (computes 13582 serialization UIDs), and gtnameserv (also for CORBA) are now 13583 installed. 13584 * The ability to dump the contents of the java run time heap to a 13585 file for off-line analysis has been added. The heap dumps may be 13586 analyzed with the new gc-analyze tool. They may be generated on 13587 out-of-memory conditions or on demand and are controlled by the new 13588 run time class gnu.gcj.util.GCInfo. 13589 * java.util.TimeZone can now read files from /usr/share/zoneinfo to 13590 provide correct, updated, timezone information. This means that 13591 packagers no longer have to update libgcj when a time zone change 13592 is published. 13593 13594 New Targets and Target Specific Improvements 13595 13596 IA-32/x86-64 13597 13598 * Tuning for Intel Core 2 processors is available via -mtune=core2 13599 and -march=core2. 13600 * Tuning for AMD Geode processors is available via -mtune=geode and 13601 -march=geode. 13602 * Code generation of block move (memcpy) and block set (memset) was 13603 rewritten. GCC can now pick the best algorithm (loop, unrolled 13604 loop, instruction with rep prefix or a library call) based on the 13605 size of the block being copied and the CPU being optimized for. A 13606 new option -minline-stringops-dynamically has been added. With this 13607 option string operations of unknown size are expanded such that 13608 small blocks are copied by in-line code, while for large blocks a 13609 library call is used. This results in faster code than 13610 -minline-all-stringops when the library implementation is capable 13611 of using cache hierarchy hints. The heuristic choosing the 13612 particular algorithm can be overwritten via -mstringop-strategy. 13613 Newly also memset of values different from 0 is inlined. 13614 * GCC no longer places the cld instruction before string operations. 13615 Both i386 and x86-64 ABI documents mandate the direction flag to be 13616 clear at the entry of a function. It is now invalid to set the flag 13617 in asm statement without reseting it afterward. 13618 * Support for SSSE3 built-in functions and code generation are 13619 available via -mssse3. 13620 * Support for SSE4.1 built-in functions and code generation are 13621 available via -msse4.1. 13622 * Support for SSE4.2 built-in functions and code generation are 13623 available via -msse4.2. 13624 * Both SSE4.1 and SSE4.2 support can be enabled via -msse4. 13625 * A new set of options -mpc32, -mpc64 and -mpc80 have been added to 13626 allow explicit control of x87 floating point precision. 13627 * Support for __float128 (TFmode) IEEE quad type and corresponding 13628 TCmode IEEE complex quad type is available via the soft-fp library 13629 on x86_64 targets. This includes basic arithmetic operations 13630 (addition, subtraction, negation, multiplication and division) on 13631 __float128 real and TCmode complex values, the full set of IEEE 13632 comparisons between __float128 values, conversions to and from 13633 float, double and long double floating point types, as well as 13634 conversions to and from signed or unsigned integer, signed or 13635 unsigned long integer and signed or unsigned quad (TImode) integer 13636 types. Additionally, all operations generate the full set of IEEE 13637 exceptions and support the full set of IEEE rounding modes. 13638 * GCC can now utilize the ACML library for vectorizing calls to a set 13639 of C99 functions on x86_64 if -mveclibabi=acml is specified and you 13640 link to an ACML ABI compatible library. 13641 13642 ARM 13643 13644 * Compiler and Library support for Thumb-2 and the ARMv7 architecture 13645 has been added. 13646 13647 CRIS 13648 13649 New features 13650 13651 * Compiler and Library support for the CRIS v32 architecture, as 13652 found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been 13653 added. 13654 13655 Configuration changes 13656 13657 * The cris-*-elf target now includes support for CRIS v32, including 13658 libraries, through the -march=v32 option. 13659 * A new crisv32-*-elf target defaults to generate code for CRIS v32. 13660 * A new crisv32-*-linux* target defaults to generate code for CRIS 13661 v32. 13662 * The cris-*-aout target has been obsoleted. 13663 13664 Improved support for built-in functions 13665 13666 * GCC can now use the lz and swapwbr instructions to implement the 13667 __builtin_clz, __builtin_ctz and __builtin_ffs family of functions. 13668 * __builtin_bswap32 is now implemented using the swapwb instruction, 13669 when available. 13670 13671 m68k and ColdFire 13672 13673 New features 13674 13675 * Support for several new ColdFire processors has been added. You can 13676 generate code for them using the new -mcpu option. 13677 * All targets now support ColdFire processors. 13678 * m68k-uclinux targets have improved support for C++ constructors and 13679 destructors, and for shared libraries. 13680 * It is now possible to set breakpoints on the first or last line of 13681 a function, even if there are no statements on that line. 13682 13683 Optimizations 13684 13685 * Support for sibling calls has been added. 13686 * More use is now made of the ColdFire mov3q instruction. 13687 * __builtin_clz is now implemented using the ff1 ColdFire 13688 instruction, when available. 13689 * GCC now honors the -m68010 option. 68010 code now uses clr rather 13690 than move to zero volatile memory. 13691 * 68020 targets and above can now use symbol(index.size*scale) 13692 addresses for indexed array accesses. Earlier compilers would 13693 always load the symbol into a base register first. 13694 13695 Configuration changes 13696 13697 * All m68k and ColdFire targets now allow the default processor to be 13698 set at configure time using --with-cpu. 13699 * A --with-arch configuration option has been added. This option 13700 allows you to restrict a target to ColdFire or non-ColdFire 13701 processors. 13702 13703 Preprocessor macros 13704 13705 * An __mcfv*__ macro is now defined for all ColdFire targets. 13706 (Earlier versions of GCC only defined __mcfv4e__.) 13707 * __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added. 13708 * All targets now define __mc68010 and __mc68010__ when generating 13709 68010 code. 13710 13711 Command-line changes 13712 13713 * New command-line options -march, -mcpu, -mtune and -mhard-float 13714 have been added. These options apply to both m68k and ColdFire 13715 targets. 13716 * -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative 13717 versions of -mshort, etc. 13718 * -fforce-addr has been removed. It is now ignored by the compiler. 13719 13720 Other improvements 13721 13722 * ColdFire targets now try to maintain a 4-byte-aligned stack where 13723 possible. 13724 * m68k-uclinux targets now try to avoid situations that lead to the 13725 load-time error: BINFMT_FLAT: reloc outside program. 13726 13727 MIPS 13728 13729 Changes to existing configurations 13730 13731 * libffi and libjava now support all three GNU/Linux ABIs: o32, n32 13732 and n64. Every GNU/Linux configuration now builds these libraries 13733 by default. 13734 * GNU/Linux configurations now generate -mno-shared code unless 13735 overridden by -fpic, -fPIC, -fpie or -fPIE. 13736 * mipsisa32*-linux-gnu configurations now generate hard-float code by 13737 default, just like other mipsisa32* and mips*-linux-gnu 13738 configurations. You can build a soft-float version of any 13739 mips*-linux-gnu configuration by passing --with-float=soft to 13740 configure. 13741 * mips-wrs-vxworks now supports run-time processes (RTPs). 13742 13743 Changes to existing command-line options 13744 13745 * The -march and -mtune options no longer accept 24k as a processor 13746 name. Please use 24kc, 24kf2_1 or 24kf1_1 instead. 13747 * The -march and -mtune options now accept 24kf2_1, 24kef2_1 and 13748 34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The 13749 options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for 13750 24kx, 24kex and 34kx. 13751 13752 New configurations 13753 13754 GCC now supports the following configurations: 13755 * mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by 13756 default. Earlier releases also recognized this configuration, but 13757 they treated it in the same way as mipsisa32*-linux-gnu*. Note that 13758 you can customize any mips*-linux-gnu* configuration to a 13759 particular ISA or processor by passing an appropriate --with-arch 13760 option to configure. 13761 * mipsisa*-sde-elf*, which provides compatibility with MIPS 13762 Technologies' SDE toolchains. The configuration uses the SDE 13763 libraries by default, but you can use it like other newlib-based 13764 ELF configurations by passing --with-newlib to configure. It is the 13765 only configuration besides mips64vr*-elf* to build MIPS16 as well 13766 as non-MIPS16 libraries. 13767 * mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf* 13768 configuration, but uses the o32 and o64 ABIs instead of the 32-bit 13769 and 64-bit forms of the EABI. 13770 13771 New processors and application-specific extensions 13772 13773 * Support for the SmartMIPS ASE is available through the new 13774 -msmartmips option. 13775 * Support for revision 2 of the DSP ASE is available through the new 13776 -mdspr2 option. A new preprocessor macro called __mips_dsp_rev 13777 indicates the revision of the ASE in use. 13778 * Support for the 4KS and 74K families of processors is available 13779 through the -march and -mtune options. 13780 13781 Improved support for built-in functions 13782 13783 * GCC can now use load-linked, store-conditional and sync 13784 instructions to implement atomic built-in functions such as 13785 __sync_fetch_and_add. The memory reference must be 4 bytes wide for 13786 32-bit targets and either 4 or 8 bytes wide for 64-bit targets. 13787 * GCC can now use the clz and dclz instructions to implement the 13788 __builtin_ctz and __builtin_ffs families of functions. 13789 * There is a new __builtin___clear_cache function for flushing the 13790 instruction cache. GCC expands this function inline on MIPS32 13791 revision 2 targets, otherwise it calls the function specified by 13792 -mcache-flush-func. 13793 13794 MIPS16 improvements 13795 13796 * GCC can now compile objects that contain a mixture of MIPS16 and 13797 non-MIPS16 code. There are two new attributes, mips16 and nomips16, 13798 for specifying which mode a function should use. 13799 * A new option called -minterlink-mips16 makes non-MIPS16 code 13800 link-compatible with MIPS16 code. 13801 * After many bug fixes, the long-standing MIPS16 -mhard-float support 13802 should now work fairly reliably. 13803 * GCC can now use the MIPS16e save and restore instructions. 13804 * -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled 13805 with -G0 -fsection-anchors is often smaller than code compiled with 13806 -G8. However, please note that you must usually compile all objects 13807 in your application with the same -G option; see the documentation 13808 of -G for details. 13809 * A new option called-mcode-readable specifies which instructions are 13810 allowed to load from the code segment. -mcode-readable=yes is the 13811 default and says that any instruction may load from the code 13812 segment. The other alternatives are -mcode-readable=pcrel, which 13813 says that only PC-relative MIPS16 instructions may load from the 13814 code segment, and -mcode-readable=no, which says that no 13815 instruction may do so. Please see the documentation for more 13816 details, including example uses. 13817 13818 Small-data improvements 13819 13820 There are three new options for controlling small data: 13821 * -mno-extern-sdata, which disables small-data accesses for 13822 externally-defined variables. Code compiled with -Gn 13823 -mno-extern-sdata will be link-compatible with any -G setting 13824 between -G0 and -Gn inclusive. 13825 * -mno-local-sdata, which disables the use of small-data sections for 13826 data that is not externally visible. This option can be a useful 13827 way of reducing small-data usage in less performance-critical parts 13828 of an application. 13829 * -mno-gpopt, which disables the use of the $gp register while still 13830 honoring the -G limit when placing externally-visible data. This 13831 option implies -mno-extern-sdata and -mno-local-sdata and it can be 13832 useful in situations where $gp does not necessarily hold the 13833 expected value. 13834 13835 Miscellaneous improvements 13836 13837 * There is a new option called -mbranch-cost for tweaking the 13838 perceived cost of branches. 13839 * If GCC is configured to use a version of GAS that supports the 13840 .gnu_attribute directive, it will use that directive to record 13841 certain properties of the output code. .gnu_attribute is new to GAS 13842 2.18. 13843 * There are two new function attributes, near and far, for overriding 13844 the command-line setting of -mlong-calls on a function-by-function 13845 basis. 13846 * -mfp64, which previously required a 64-bit target, now works with 13847 MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and 13848 mipsisa*-sde-elf* configurations provide suitable library support. 13849 * GCC now recognizes the -mdmx and -mmt options and passes them down 13850 to the assembler. It does nothing else with the options at present. 13851 13852 SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture 13853 (BEA) 13854 13855 * Support has been added for this new architecture. 13856 13857 RS6000 (POWER/PowerPC) 13858 13859 * Support for the PowerPC 750CL paired-single instructions has been 13860 added with a new powerpc-*-linux*paired* target configuration. It 13861 is enabled by an associated -mpaired option and can be accessed 13862 using new built-in functions. 13863 * Support for auto-detecting architecture and system configuration to 13864 auto-select processor optimization tuning. 13865 * Support for VMX on AIX 5.3 has been added. 13866 * Support for AIX Version 6.1 has been added. 13867 13868 S/390, zSeries and System z9 13869 13870 * Support for the IBM System z9 EC/BC processor (z9 GA3) has been 13871 added. When using the -march=z9-ec option, the compiler will 13872 generate code making use of instructions provided by the decimal 13873 floating point facility and the floating point conversion facility 13874 (pfpo). Besides the instructions used to implement decimal floating 13875 point operations these facilities also contain instructions to move 13876 between general purpose and floating point registers and to modify 13877 and copy the sign-bit of floating point values. 13878 * When the -march=z9-ec option is used the new 13879 -mhard-dfp/-mno-hard-dfp options can be used to specify whether the 13880 decimal floating point hardware instructions will be used or not. 13881 If none of them is given the hardware support is enabled by 13882 default. 13883 * The -mstack-guard option can now be omitted when using stack 13884 checking via -mstack-size in order to let GCC choose a sensible 13885 stack guard value according to the frame size of each function. 13886 * Various changes to improve performance of generated code have been 13887 implemented, including: 13888 + The condition code set by an add logical with carry 13889 instruction is now available for overflow checks like: a + b + 13890 carry < b. 13891 + The test data class instruction is now used to implement 13892 sign-bit and infinity checks of binary and decimal floating 13893 point numbers. 13894 13895 SPARC 13896 13897 * Support for the Sun UltraSPARC T2 (Niagara 2) processor has been 13898 added. 13899 13900 Xtensa 13901 13902 * Stack unwinding for exception handling now uses by default a 13903 specialized version of DWARF unwinding. This is not 13904 binary-compatible with the setjmp/longjmp (sjlj) unwinding used for 13905 Xtensa with previous versions of GCC. 13906 * For Xtensa processors that include the Conditional Store option, 13907 the built-in functions for atomic memory access are now implemented 13908 using S32C1I instructions. 13909 * If the Xtensa NSA option is available, GCC will use it to implement 13910 the __builtin_ctz and __builtin_clz functions. 13911 13912 Documentation improvements 13913 13914 * Existing libstdc++ documentation has been edited and restructured 13915 into a single DocBook XML manual. The results can be viewed online 13916 [18]here. 13917 13918 Other significant improvements 13919 13920 * The compiler's --help command-line option has been extended so that 13921 it now takes an optional set of arguments. These arguments restrict 13922 the information displayed to specific classes of command-line 13923 options, and possibly only a subset of those options. It is also 13924 now possible to replace the descriptive text associated with each 13925 displayed option with an indication of its current value, or for 13926 binary options, whether it has been enabled or disabled. 13927 Here are some examples. The following will display all the options 13928 controlling warning messages: 13929 --help=warnings 13930 13931 Whereas this will display all the undocumented, target specific 13932 options: 13933 --help=target,undocumented 13934 13935 This sequence of commands will display the binary optimizations 13936 that are enabled by -O3: 13937 gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts 13938 gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts 13939 diff /tmp/O2-opts /tmp/O3-opts | grep enabled 13940 13941 * The configure options --with-pkgversion and --with-bugurl have been 13942 added. These allow distributors of GCC to include a 13943 distributor-specific string in manuals and --version output and to 13944 specify the URL for reporting bugs in their versions of GCC. 13945 13946 GCC 4.3.1 13947 13948 This is the [19]list of problem reports (PRs) from GCC's bug tracking 13949 system that are known to be fixed in the 4.3.1 release. This list might 13950 not be complete (that is, it is possible that some PRs that have been 13951 fixed are not listed here). 13952 13953 Target Specific Changes 13954 13955 IA-32/x86-64 13956 13957 ABI changes 13958 13959 * Starting with GCC 4.3.1, decimal floating point variables are 13960 aligned to their natural boundaries when they are passed on the 13961 stack for i386. 13962 13963 Command-line changes 13964 13965 * Starting with GCC 4.3.1, the -mcld option has been added to 13966 automatically generate a cld instruction in the prologue of 13967 functions that use string instructions. This option is used for 13968 backward compatibility on some operating systems and can be enabled 13969 by default for 32-bit x86 targets by configuring GCC with the 13970 --enable-cld configure option. 13971 13972 GCC 4.3.2 13973 13974 This is the [20]list of problem reports (PRs) from GCC's bug tracking 13975 system that are known to be fixed in the 4.3.2 release. This list might 13976 not be complete (that is, it is possible that some PRs that have been 13977 fixed are not listed here). 13978 13979 GCC 4.3.3 13980 13981 This is the [21]list of problem reports (PRs) from GCC's bug tracking 13982 system that are known to be fixed in the 4.3.3 release. This list might 13983 not be complete (that is, it is possible that some PRs that have been 13984 fixed are not listed here). 13985 13986 GCC 4.3.4 13987 13988 This is the [22]list of problem reports (PRs) from GCC's bug tracking 13989 system that are known to be fixed in the 4.3.4 release. This list might 13990 not be complete (that is, it is possible that some PRs that have been 13991 fixed are not listed here). 13992 13993 GCC 4.3.5 13994 13995 This is the [23]list of problem reports (PRs) from GCC's bug tracking 13996 system that are known to be fixed in the 4.3.5 release. This list might 13997 not be complete (that is, it is possible that some PRs that have been 13998 fixed are not listed here). 13999 14000 GCC 4.3.6 14001 14002 This is the [24]list of problem reports (PRs) from GCC's bug tracking 14003 system that are known to be fixed in the 4.3.6 release. This list might 14004 not be complete (that is, it is possible that some PRs that have been 14005 fixed are not listed here). 14006 14007 14008 For questions related to the use of GCC, please consult these web 14009 pages and the [25]GCC manuals. If that fails, the 14010 [26]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 14011 web pages and the development of GCC are welcome on our developer 14012 list at [27]gcc (a] gcc.gnu.org. All of [28]our lists have public 14013 archives. 14014 14015 Copyright (C) [29]Free Software Foundation, Inc. Verbatim copying and 14016 distribution of this entire article is permitted in any medium, 14017 provided this notice is preserved. 14018 14019 These pages are [30]maintained by the GCC team. Last modified 14020 2022-10-26. 14021 14022 References 14023 14024 1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.5 14025 2. https://gmplib.org/ 14026 3. https://www.mpfr.org/ 14027 4. https://gcc.gnu.org/install/prerequisites.html 14028 5. https://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html 14029 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 14030 7. http://gcc.gnu.org/gcc-4.3/porting_to.html 14031 8. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 14032 9. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 14033 10. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 14034 11. https://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html 14035 12. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options 14036 13. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167 14037 14. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html 14038 15. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html 14039 16. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html 14040 17. https://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html 14041 18. https://gcc.gnu.org/onlinedocs/libstdc++/ 14042 19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1 14043 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2 14044 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3 14045 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4 14046 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.5 14047 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.6 14048 25. https://gcc.gnu.org/onlinedocs/ 14049 26. mailto:gcc-help (a] gcc.gnu.org 14050 27. mailto:gcc (a] gcc.gnu.org 14051 28. https://gcc.gnu.org/lists.html 14052 29. https://www.fsf.org/ 14053 30. https://gcc.gnu.org/about.html 14054 ====================================================================== 14055 http://gcc.gnu.org/gcc-4.2/index.html 14056 14057 GCC 4.2 Release Series 14058 14059 (This release series is no longer supported.) 14060 14061 May 19, 2008 14062 14063 The [1]GNU project and the GCC developers are pleased to announce the 14064 release of GCC 4.2.4. 14065 14066 This release is a bug-fix release, containing fixes for regressions in 14067 GCC 4.2.3 relative to previous releases of GCC. 14068 14069 Release History 14070 14071 GCC 4.2.4 14072 May 19, 2008 ([2]changes) 14073 14074 GCC 4.2.3 14075 February 1, 2008 ([3]changes) 14076 14077 GCC 4.2.2 14078 October 7, 2007 ([4]changes) 14079 14080 GCC 4.2.1 14081 July 18, 2007 ([5]changes) 14082 14083 GCC 4.2.0 14084 May 13, 2007 ([6]changes) 14085 14086 References and Acknowledgements 14087 14088 GCC used to stand for the GNU C Compiler, but since the compiler 14089 supports several other languages aside from C, it now stands for the 14090 GNU Compiler Collection. 14091 14092 A list of [7]successful builds is updated as new information becomes 14093 available. 14094 14095 The GCC developers would like to thank the numerous people that have 14096 contributed new features, improvements, bug fixes, and other changes as 14097 well as test results to GCC. This [8]amazing group of volunteers is 14098 what makes GCC successful. 14099 14100 For additional information about GCC please refer to the [9]GCC project 14101 web site or contact the [10]GCC development mailing list. 14102 14103 To obtain GCC please use [11]our mirror sites or [12]our version 14104 control system. 14105 14106 14107 For questions related to the use of GCC, please consult these web 14108 pages and the [13]GCC manuals. If that fails, the 14109 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 14110 web pages and the development of GCC are welcome on our developer 14111 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 14112 archives. 14113 14114 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 14115 distribution of this entire article is permitted in any medium, 14116 provided this notice is preserved. 14117 14118 These pages are [18]maintained by the GCC team. Last modified 14119 2022-10-26. 14120 14121 References 14122 14123 1. http://www.gnu.org/ 14124 2. http://gcc.gnu.org/gcc-4.2/changes.html 14125 3. http://gcc.gnu.org/gcc-4.2/changes.html 14126 4. http://gcc.gnu.org/gcc-4.2/changes.html 14127 5. http://gcc.gnu.org/gcc-4.2/changes.html 14128 6. http://gcc.gnu.org/gcc-4.2/changes.html 14129 7. http://gcc.gnu.org/gcc-4.2/buildstat.html 14130 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 14131 9. http://gcc.gnu.org/index.html 14132 10. mailto:gcc (a] gcc.gnu.org 14133 11. http://gcc.gnu.org/mirrors.html 14134 12. http://gcc.gnu.org/git.html 14135 13. https://gcc.gnu.org/onlinedocs/ 14136 14. mailto:gcc-help (a] gcc.gnu.org 14137 15. mailto:gcc (a] gcc.gnu.org 14138 16. https://gcc.gnu.org/lists.html 14139 17. https://www.fsf.org/ 14140 18. https://gcc.gnu.org/about.html 14141 ====================================================================== 14142 http://gcc.gnu.org/gcc-4.2/changes.html 14143 14144 GCC 4.2 Release Series 14145 Changes, New Features, and Fixes 14146 14147 Caveats 14148 14149 * GCC no longer accepts the -fshared-data option. This option has had 14150 no effect in any GCC 4 release; the targets to which the option 14151 used to apply had been removed before GCC 4.0. 14152 14153 General Optimizer Improvements 14154 14155 * New command-line options specify the possible relationships among 14156 parameters and between parameters and global data. For example, 14157 -fargument-noalias-anything specifies that arguments do not alias 14158 any other storage. 14159 Each language will automatically use whatever option is required by 14160 the language standard. You should not need to use these options 14161 yourself. 14162 14163 New Languages and Language specific improvements 14164 14165 * [1]OpenMP is now supported for the C, C++ and Fortran compilers. 14166 * New command-line options -fstrict-overflow and -Wstrict-overflow 14167 have been added. -fstrict-overflow tells the compiler that it may 14168 assume that the program follows the strict signed overflow 14169 semantics permitted for the language: for C and C++ this means that 14170 the compiler may assume that signed overflow does not occur. For 14171 example, a loop like 14172 for (i = 1; i > 0; i *= 2) 14173 14174 is presumably intended to continue looping until i overflows. With 14175 -fstrict-overflow, the compiler may assume that signed overflow 14176 will not occur, and transform this into an infinite loop. 14177 -fstrict-overflow is turned on by default at -O2, and may be 14178 disabled via -fno-strict-overflow. The -Wstrict-overflow option may 14179 be used to warn about cases where the compiler assumes that signed 14180 overflow will not occur. It takes five different levels: 14181 -Wstrict-overflow=1 to 5. See the [2]documentation for details. 14182 -Wstrict-overflow=1 is enabled by -Wall. 14183 * The new command-line option -fno-toplevel-reorder directs GCC to 14184 emit top-level functions, variables, and asm statements in the same 14185 order that they appear in the input file. This is intended to 14186 support existing code which relies on a particular ordering (for 14187 example, code which uses top-level asm statements to switch 14188 sections). For new code, it is generally better to use function and 14189 variable attributes. The -fno-toplevel-reorder option may be used 14190 for most cases which currently use -fno-unit-at-a-time. The 14191 -fno-unit-at-a-time option will be removed in some future version 14192 of GCC. If you know of a case which requires -fno-unit-at-a-time 14193 which is not fixed by -fno-toplevel-reorder, please open a bug 14194 report. 14195 14196 C family 14197 14198 * The pragma redefine_extname will now macro expand its tokens for 14199 compatibility with SunPRO. 14200 * In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct 14201 GCC to handle inline functions as specified in the C99 standard. In 14202 preparation for this, GCC 4.2 will warn about any use of non-static 14203 inline functions in gnu99 or c99 mode. This new warning may be 14204 disabled with the new gnu_inline function attribute or the new 14205 -fgnu89-inline command-line option. Also, GCC 4.2 and later will 14206 define one of the preprocessor macros __GNUC_GNU_INLINE__ or 14207 __GNUC_STDC_INLINE__ to indicate the semantics of inline functions 14208 in the current compilation. 14209 * A new command-line option -Waddress has been added to warn about 14210 suspicious uses of memory addresses as, for example, using the 14211 address of a function in a conditional expression, and comparisons 14212 against the memory address of a string literal. This warning is 14213 enabled by -Wall. 14214 14215 C++ 14216 14217 * C++ visibility handling has been overhauled. 14218 Restricted visiblity is propagated from classes to members, from 14219 functions to local statics, and from templates and template 14220 arguments to instantiations, unless the latter has explicitly 14221 declared visibility. 14222 The visibility attribute for a class must come between the 14223 class-key and the name, not after the closing brace. 14224 Attributes are now allowed for enums and elaborated-type-specifiers 14225 that only declare a type. 14226 Members of the anonymous namespace are now local to a particular 14227 translation unit, along with any other declarations which use them, 14228 though they are still treated as having external linkage for 14229 language semantics. 14230 * The (undocumented) extension which permitted templates with default 14231 arguments to be bound to template template parameters with fewer 14232 parameters has been removed. For example: 14233 template <template <typename> class C> 14234 void f(C<double>) {} 14235 14236 template <typename T, typename U = int> 14237 struct S {}; 14238 14239 template void f(S<double>); 14240 14241 is no longer accepted by G++. The reason this code is not accepted 14242 is that S is a template with two parameters; therefore, it cannot 14243 be bound to C which has only one parameter. 14244 * The <?, >?, <?=, and >?= operators, deprecated in previous GCC 14245 releases, have been removed. 14246 * The command-line option -fconst-strings, deprecated in previous GCC 14247 releases, has been removed. 14248 * The configure variable enable-__cxa_atexit is now enabled by 14249 default for more targets. Enabling this variable is necessary in 14250 order for static destructors to be executed in the correct order, 14251 but it depends upon the presence of a non-standard C library in the 14252 target library in order to work. The variable is now enabled for 14253 more targets which are known to have suitable C libraries. 14254 * -Wextra will produce warnings for if statements with a semicolon as 14255 the only body, to catch code like: 14256 if (a); 14257 return 1; 14258 return 0; 14259 14260 To suppress the warning in valid cases, use { } instead. 14261 * The C++ front end now also produces strict aliasing warnings when 14262 -fstrict-aliasing -Wstrict-aliasing is in effect. 14263 14264 Runtime Library (libstdc++) 14265 14266 * Added support for TR1 <random>, <complex>, and C compatibility 14267 headers. In addition, a lock-free version of shared_ptr was 14268 contributed as part of Phillip Jordan's Google Summer of Code 14269 project on lock-free containers. 14270 * In association with the Summer of Code work on lock-free 14271 containers, the interface for atomic builtins was adjusted, 14272 creating simpler alternatives for non-threaded code paths. Also, 14273 usage was consolidated and all elements were moved from namespace 14274 std to namespace__gnu_cxx. Affected interfaces are the functions 14275 __exchange_and_add, __atomic_add, and the objects __mutex, 14276 __recursive_mutex, and __scoped_lock. 14277 * Support for versioning weak symbol names via namespace association 14278 was added. However, as this changes the names of exported symbols, 14279 this is turned off by default in the current ABI. Intrepid users 14280 can enable this feature by using 14281 --enable-symvers=gnu-versioned-namespace during configuration. 14282 * Revised, simplified, and expanded policy-based associative 14283 containers, including data types for tree and trie forms 14284 (basic_tree, tree, trie), lists (list_update), and both 14285 collision-chaining and probing hash-based containers 14286 (basic_hash_table, cc_hash_table, gp_hash_table). More details per 14287 the [3]documentation. 14288 * The implementation of the debug mode was modified, whereby the 14289 debug namespaces were nested inside of namespace std and namespace 14290 __gnu_cxx in order to resolve some long standing corner cases 14291 involving name lookup. Debug functionality from the policy-based 14292 data structures was consolidated and enabled with the single macro, 14293 _GLIBCXX_DEBUG. See PR 26142 for more information. 14294 * Added extensions for type traits: __conditional_type, 14295 __numeric_traits, __add_unsigned, __removed_unsigned, __enable_if. 14296 * Added a typelist implementation for compile-time meta-programming. 14297 Elements for typelist construction and operation can be found 14298 within namespace __gnu_cxx::typelist. 14299 * Added a new allocator, __gnu_cxx::throw_allocator, for testing 14300 exception-safety. 14301 * Enabled library-wide visibility control, allowing -fvisibility to 14302 be used. 14303 * Consolidated all nested namespaces and the conversion of 14304 __gnu_internal implementation-private details to anonymous 14305 namespaces whenever possible. 14306 * Implemented LWG resolutions DR 431 and DR 538. 14307 14308 Fortran 14309 14310 * Support for allocatable components has been added (TR 15581 and 14311 Fortran 2003). 14312 * Support for the Fortran 2003 streaming IO extension has been added. 14313 * The GNU Fortran compiler now uses 4-byte record markers by default 14314 for unformatted files to be compatible with g77 and most other 14315 compilers. The implementation allows for records greater than 2 GB 14316 and is compatible with several other compilers. Older versions of 14317 gfortran used 8-byte record markers by default (on most systems). 14318 In order to change the length of the record markers, e.g. to read 14319 unformatted files created by older gfortran versions, the 14320 [4]-frecord-marker=8 option can be used. 14321 14322 Java (GCJ) 14323 14324 * A new command-line option -static-libgcj has been added for targets 14325 that use a linker compatible with GNU Binutils. As its name 14326 implies, this causes libgcj to be linked statically. In some cases 14327 this causes the resulting executable to start faster and use less 14328 memory than if the shared version of libgcj were used. However 14329 caution should be used as it can also cause essential parts of the 14330 library to be omitted. Some of these issues are discussed in: 14331 [5]https://gcc.gnu.org/wiki/Statically_linking_libgcj 14332 * fastjar is no longer bundled with GCC. To build libgcj, you will 14333 need either InfoZIP (both zip and unzip) or an external jar 14334 program. In the former case, the GCC build will install a jar shell 14335 script that is based on InfoZIP and provides the same functionality 14336 as fastjar. 14337 14338 New Targets and Target Specific Improvements 14339 14340 IA-32/x86-64 14341 14342 * -mtune=generic can now be used to generate code running well on 14343 common x86 chips. This includes AMD Athlon, AMD Opteron, Intel 14344 Pentium-M, Intel Pentium 4 and Intel Core 2. 14345 * -mtune=native and -march=native will produce code optimized for the 14346 host architecture as detected using the cpuid instruction. 14347 * Added a new command-line option -fstackrealign and and 14348 __attribute__ ((force_align_arg_pointer)) to realign the stack at 14349 runtime. This allows functions compiled with a vector-aligned stack 14350 to be invoked from legacy objects that keep only word-alignment. 14351 14352 SPARC 14353 14354 * The default CPU setting has been changed from V7 to V9 in 32-bit 14355 mode on Solaris 7 and above. This is already the case in 64-bit 14356 mode. It can be overridden by specifying --with-cpu at configure 14357 time. 14358 * Back-end support of built-in functions for atomic memory access has 14359 been implemented. 14360 * Support for the Sun UltraSPARC T1 (Niagara) processor has been 14361 added. 14362 14363 M32C 14364 14365 * Various bug fixes have made some functions (notably, functions 14366 returning structures) incompatible with previous releases. 14367 Recompiling all libraries is recommended. Note that code quality 14368 has considerably improved since 4.1, making a recompile even more 14369 beneficial. 14370 14371 MIPS 14372 14373 * Added support for the Broadcom SB-1A core. 14374 14375 IA-64 14376 14377 * Added support for IA-64 data and control speculation. By default 14378 speculation is enabled only during second scheduler pass. A number 14379 of machine flags was introduced to control the usage of speculation 14380 for both scheduler passes. 14381 14382 HPPA 14383 14384 * Added Java language support (libffi and libjava) for 32-bit HP-UX 14385 11 target. 14386 14387 Obsolete Systems 14388 14389 Documentation improvements 14390 14391 PDF Documentation 14392 14393 * A make pdf target has been added to the top-level makefile, 14394 enabling automated production of PDF documentation files. 14395 (Front-ends external to GCC should modify their Make-lang.in file 14396 to add a lang.pdf: target.) 14397 14398 Other significant improvements 14399 14400 Build system improvements 14401 14402 * All the components of the compiler are now bootstrapped by default. 14403 This improves the resilience to bugs in the system compiler or 14404 binary compatibility problems, as well as providing better testing 14405 of GCC 4.2 itself. In addition, if you build the compiler from a 14406 combined tree, the assembler, linker, etc. will also be 14407 bootstrapped (i.e. built with themselves). 14408 You can disable this behavior, and go back to the pre-GCC 4.2 set 14409 up, by configuring GCC with --disable-bootstrap. 14410 * The rules that configure follows to find target tools resemble more 14411 closely the locations that the built compiler will search. In 14412 addition, you can use the new configure option --with-target-tools 14413 to specify where to find the target tools used during the build, 14414 without affecting what the built compiler will use. 14415 This can be especially useful when building packages of GCC. For 14416 example, you may want to build GCC with GNU as or ld, even if the 14417 resulting compiler to work with the native assembler and linker. To 14418 do so, you can use --with-target-tools to point to the native 14419 tools. 14420 14421 Incompatible changes to the build system 14422 14423 * Front-ends external to GCC should modify their Make-lang.in file to 14424 replace double-colon rules (e.g. dvi::) with normal rules (like 14425 lang.dvi:). Front-end makefile hooks do not use double-colon rules 14426 anymore. 14427 * Up to GCC 4.1, a popular way to specify the target tools used 14428 during the build was to create directories named gas, binutils, 14429 etc. in the build tree, and create links to the tools from there. 14430 This does not work any more when the compiler is bootstrapped. The 14431 new configure option --with-target-tools provides a better way to 14432 achieve the same effect, and works for all native and cross 14433 settings. 14434 14435 14436 For questions related to the use of GCC, please consult these web 14437 pages and the [6]GCC manuals. If that fails, the 14438 [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 14439 web pages and the development of GCC are welcome on our developer 14440 list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives. 14441 14442 Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and 14443 distribution of this entire article is permitted in any medium, 14444 provided this notice is preserved. 14445 14446 These pages are [11]maintained by the GCC team. Last modified 14447 2022-10-26. 14448 14449 References 14450 14451 1. http://gcc.gnu.org/projects/gomp/ 14452 2. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 14453 3. https://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html 14454 4. https://gcc.gnu.org/onlinedocs/gfortran/Runtime-Options.html 14455 5. https://gcc.gnu.org/wiki/Statically_linking_libgcj 14456 6. https://gcc.gnu.org/onlinedocs/ 14457 7. mailto:gcc-help (a] gcc.gnu.org 14458 8. mailto:gcc (a] gcc.gnu.org 14459 9. https://gcc.gnu.org/lists.html 14460 10. https://www.fsf.org/ 14461 11. https://gcc.gnu.org/about.html 14462 ====================================================================== 14463 http://gcc.gnu.org/gcc-4.1/index.html 14464 14465 GCC 4.1 Release Series 14466 14467 (This release series is no longer supported.) 14468 14469 February 13, 2007 14470 14471 The [1]GNU project and the GCC developers are pleased to announce the 14472 release of GCC 4.1.2. 14473 14474 This release is a bug-fix release, containing fixes for regressions in 14475 GCC 4.1.1 relative to previous releases of GCC. 14476 14477 Release History 14478 14479 GCC 4.1.2 14480 February 13, 2007 ([2]changes) 14481 14482 GCC 4.1.1 14483 May 24, 2006 ([3]changes) 14484 14485 GCC 4.1.0 14486 February 28, 2006 ([4]changes) 14487 14488 References and Acknowledgements 14489 14490 GCC used to stand for the GNU C Compiler, but since the compiler 14491 supports several other languages aside from C, it now stands for the 14492 GNU Compiler Collection. 14493 14494 A list of [5]successful builds is updated as new information becomes 14495 available. 14496 14497 The GCC developers would like to thank the numerous people that have 14498 contributed new features, improvements, bug fixes, and other changes as 14499 well as test results to GCC. This [6]amazing group of volunteers is 14500 what makes GCC successful. 14501 14502 For additional information about GCC please refer to the [7]GCC project 14503 web site or contact the [8]GCC development mailing list. 14504 14505 To obtain GCC please use [9]our mirror sites or [10]our version control 14506 system. 14507 14508 14509 For questions related to the use of GCC, please consult these web 14510 pages and the [11]GCC manuals. If that fails, the 14511 [12]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 14512 web pages and the development of GCC are welcome on our developer 14513 list at [13]gcc (a] gcc.gnu.org. All of [14]our lists have public 14514 archives. 14515 14516 Copyright (C) [15]Free Software Foundation, Inc. Verbatim copying and 14517 distribution of this entire article is permitted in any medium, 14518 provided this notice is preserved. 14519 14520 These pages are [16]maintained by the GCC team. Last modified 14521 2022-10-26. 14522 14523 References 14524 14525 1. http://www.gnu.org/ 14526 2. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 14527 3. http://gcc.gnu.org/gcc-4.1/changes.html 14528 4. http://gcc.gnu.org/gcc-4.1/changes.html 14529 5. http://gcc.gnu.org/gcc-4.1/buildstat.html 14530 6. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 14531 7. http://gcc.gnu.org/index.html 14532 8. mailto:gcc (a] gcc.gnu.org 14533 9. http://gcc.gnu.org/mirrors.html 14534 10. http://gcc.gnu.org/git.html 14535 11. https://gcc.gnu.org/onlinedocs/ 14536 12. mailto:gcc-help (a] gcc.gnu.org 14537 13. mailto:gcc (a] gcc.gnu.org 14538 14. https://gcc.gnu.org/lists.html 14539 15. https://www.fsf.org/ 14540 16. https://gcc.gnu.org/about.html 14541 ====================================================================== 14542 http://gcc.gnu.org/gcc-4.1/changes.html 14543 14544 GCC 4.1 Release Series 14545 Changes, New Features, and Fixes 14546 14547 The latest release in the 4.1 release series is [1]GCC 4.1.2. 14548 14549 Caveats 14550 14551 General Optimizer Improvements 14552 14553 * GCC now has infrastructure for inter-procedural optimizations and 14554 the following inter-procedural optimizations are implemented: 14555 + Profile guided inlining. When doing profile feedback guided 14556 optimization, GCC can now use the profile to make better 14557 informed decisions on whether inlining of a function is 14558 profitable or not. This means that GCC will no longer inline 14559 functions at call sites that are not executed very often, and 14560 that functions at hot call sites are more likely to be 14561 inlined. 14562 A new parameter min-inline-recursive-probability is also now 14563 available to throttle recursive inlining of functions with 14564 small average recursive depths. 14565 + Discovery of pure and const functions, a form of side-effects 14566 analysis. While older GCC releases could also discover such 14567 special functions, the new IPA-based pass runs earlier so that 14568 the results are available to more optimizers. The pass is also 14569 simply more powerful than the old one. 14570 + Analysis of references to static variables and type escape 14571 analysis, also forms of side-effects analysis. The results of 14572 these passes allow the compiler to be less conservative about 14573 call-clobbered variables and references. This results in more 14574 redundant loads being eliminated and in making static 14575 variables candidates for register promotion. 14576 + Improvement of RTL-based alias analysis. The results of type 14577 escape analysis are fed to the RTL type-based alias analyzer, 14578 allowing it to disambiguate more memory references. 14579 + Interprocedural constant propagation and function versioning. 14580 This pass looks for functions that are always called with the 14581 same constant value for one or more of the function arguments, 14582 and propagates those constants into those functions. 14583 + GCC will now eliminate static variables whose usage was 14584 optimized out. 14585 + -fwhole-program --combine can now be used to make all 14586 functions in program static allowing whole program 14587 optimization. As an exception, the main function and all 14588 functions marked with the new externally_visible attribute are 14589 kept global so that programs can link with runtime libraries. 14590 * GCC can now do a form of partial dead code elimination (PDCE) that 14591 allows code motion of expressions to the paths where the result of 14592 the expression is actually needed. This is not always a win, so the 14593 pass has been limited to only consider profitable cases. Here is an 14594 example: 14595 int foo (int *, int *); 14596 int 14597 bar (int d) 14598 { 14599 int a, b, c; 14600 b = d + 1; 14601 c = d + 2; 14602 a = b + c; 14603 if (d) 14604 { 14605 foo (&b, &c); 14606 a = b + c; 14607 } 14608 printf ("%d\n", a); 14609 } 14610 14611 The a = b + c can be sunk to right before the printf. Normal code 14612 sinking will not do this, it will sink the first one above into the 14613 else-branch of the conditional jump, which still gives you two 14614 copies of the code. 14615 * GCC now has a value range propagation pass. This allows the 14616 compiler to eliminate bounds checks and branches. The results of 14617 the pass can also be used to accurately compute branch 14618 probabilities. 14619 * The pass to convert PHI nodes to straight-line code (a form of 14620 if-conversion for GIMPLE) has been improved significantly. The two 14621 most significant improvements are an improved algorithm to 14622 determine the order in which the PHI nodes are considered, and an 14623 improvement that allow the pass to consider if-conversions of basic 14624 blocks with more than two predecessors. 14625 * Alias analysis improvements. GCC can now differentiate between 14626 different fields of structures in Tree-SSA's virtual operands form. 14627 This lets stores/loads from non-overlapping structure fields not 14628 conflict. A new algorithm to compute points-to sets was contributed 14629 that can allows GCC to see now that p->a and p->b, where p is a 14630 pointer to a structure, can never point to the same field. 14631 * Various enhancements to auto-vectorization: 14632 + Incrementally preserve SSA form when vectorizing. 14633 + Incrementally preserve loop-closed form when vectorizing. 14634 + Improvements to peeling for alignment: generate better code 14635 when the misalignment of an access is known at compile time, 14636 or when different accesses are known to have the same 14637 misalignment, even if the misalignment amount itself is 14638 unknown. 14639 + Consider dependence distance in the vectorizer. 14640 + Externalize generic parts of data reference analysis to make 14641 this analysis available to other passes. 14642 + Vectorization of conditional code. 14643 + Reduction support. 14644 * GCC can now partition functions in sections of hot and cold code. 14645 This can significantly improve performance due to better 14646 instruction cache locality. This feature works best together with 14647 profile feedback driven optimization. 14648 * A new pass to avoid saving of unneeded arguments to the stack in 14649 vararg functions if the compiler can prove that they will not be 14650 needed. 14651 * Transition of basic block profiling to tree level implementation 14652 has been completed. The new implementation should be considerably 14653 more reliable (hopefully avoiding profile mismatch errors when 14654 using -fprofile-use or -fbranch-probabilities) and can be used to 14655 drive higher level optimizations, such as inlining. 14656 The -ftree-based-profiling command-line option was removed and 14657 -fprofile-use now implies disabling old RTL level loop optimizer 14658 (-fno-loop-optimize). Speculative prefetching optimization 14659 (originally enabled by -fspeculative-prefetching) was removed. 14660 14661 New Languages and Language specific improvements 14662 14663 C and Objective-C 14664 14665 * The old Bison-based C and Objective-C parser has been replaced by a 14666 new, faster hand-written recursive-descent parser. 14667 14668 Ada 14669 14670 * The build infrastructure for the Ada runtime library and tools has 14671 been changed to be better integrated with the rest of the build 14672 infrastructure of GCC. This should make doing cross builds of Ada a 14673 bit easier. 14674 14675 C++ 14676 14677 * ARM-style name-injection of friend declarations is no longer the 14678 default. For example: 14679 struct S { 14680 friend void f(); 14681 }; 14682 14683 void g() { f(); } 14684 will not be accepted; instead a declaration of f will need to be 14685 present outside of the scope of S. The new -ffriend-injection 14686 option will enable the old behavior. 14687 * The (undocumented) extension which permitted templates with default 14688 arguments to be bound to template template parameters with fewer 14689 parameters has been deprecated, and will be removed in the next 14690 major release of G++. For example: 14691 template <template <typename> class C> 14692 void f(C<double>) {} 14693 14694 template <typename T, typename U = int> 14695 struct S {}; 14696 14697 template void f(S<double>); 14698 14699 makes use of the deprecated extension. The reason this code is not 14700 valid ISO C++ is that S is a template with two parameters; 14701 therefore, it cannot be bound to C which has only one parameter. 14702 14703 Runtime Library (libstdc++) 14704 14705 * Optimization work: 14706 + A new implementation of std::search_n is provided, better 14707 performing in case of random access iterators. 14708 + Added further efficient specializations of istream functions, 14709 i.e., character array and string extractors. 14710 + Other smaller improvements throughout. 14711 * Policy-based associative containers, designed for high-performance, 14712 flexibility and semantic safety are delivered in ext/pb_assoc. 14713 * A versatile string class, __gnu_cxx::__versa_string, providing 14714 facilities conforming to the standard requirements for 14715 basic_string, is delivered in <ext/vstring.h>. In particular: 14716 + Two base classes are provided: the default one avoids 14717 reference counting and is optimized for short strings; the 14718 alternate one, still uses it while improving in a few low 14719 level areas (e.g., alignment). See vstring_fwd.h for some 14720 useful typedefs. 14721 + Various algorithms have been rewritten (e.g., replace), the 14722 code streamlined and simple optimizations added. 14723 + Option 3 of DR 431 is implemented for both available bases, 14724 thus improving the support for stateful allocators. 14725 * As usual, many bugs have been fixed (e.g., libstdc++/13583, 14726 libstdc++/23953) and LWG resolutions put into effect for the first 14727 time (e.g., DR 280, DR 464, N1780 recommendations for DR 233, TR1 14728 Issue 6.19). The implementation status of TR1 is now tracked in the 14729 docs in tr1.html. 14730 14731 Objective-C++ 14732 14733 * A new language front end for Objective-C++ has been added. This 14734 language allows users to mix the object oriented features of 14735 Objective-C with those of C++. 14736 14737 Java (GCJ) 14738 14739 * Core library (libgcj) updates based on GNU Classpath 0.15 - 0.19 14740 features (plus some 0.20 bug-fixes) 14741 + Networking 14742 o The java.net.HttpURLConnection implementation no longer 14743 buffers the entire response body in memory. This means 14744 that response bodies larger than available memory can now 14745 be handled. 14746 + (N)IO 14747 o NIO FileChannel.map implementation, fast bulk put 14748 implementation for DirectByteBuffer (speeds up this 14749 method 10x). 14750 o FileChannel.lock() and FileChannel.force() implemented. 14751 + XML 14752 o gnu.xml fix for nodes created outside a namespace 14753 context. 14754 o Add support for output indenting and 14755 cdata-section-elements output instruction in 14756 xml.transform. 14757 o xml.xpath corrections for cases where elements/attributes 14758 might have been created in non-namespace-aware mode. 14759 Corrections to handling of XSL variables and minor 14760 conformance updates. 14761 + AWT 14762 o GNU JAWT implementation, the AWT Native Interface, which 14763 allows direct access to native screen resources from 14764 within a Canvas's paint method. GNU Classpath Examples 14765 comes with a Demo, see libjava/classpath/examples/README. 14766 o awt.datatransfer updated to 1.5 with support for 14767 FlavorEvents. The gtk+ awt peers now allow copy/paste of 14768 text, images, URIs/files and serialized objects with 14769 other applications and tracking clipboard change events 14770 with gtk+ 2.6 (for gtk+ 2.4 only text and serialized 14771 objects are supported). A GNU Classpath Examples 14772 datatransfer Demo was added to show the new 14773 functionality. 14774 o Split gtk+ awt peers event handling in two threads and 14775 improve gdk lock handling (solves several awt lock ups). 14776 o Speed up awt Image loading. 14777 o Better gtk+ scrollbar peer implementation when using gtk+ 14778 >= 2.6. 14779 o Handle image loading errors correctly for gdkpixbuf and 14780 MediaTracker. 14781 o Better handle GDK lock. Properly prefix gtkpeer native 14782 functions (cp_gtk). 14783 o GdkGraphics2D has been updated to use Cairo 0.5.x or 14784 higher. 14785 o BufferedImage and GtkImage rewrites. All image drawing 14786 operations should now work correctly (flipping requires 14787 gtk+ >= 2.6) 14788 o When gtk+ 2.6 or higher is installed the default log 14789 handler will produce stack traces whenever a WARNING, 14790 CRITICAL or ERROR message is produced. 14791 + Free Swing 14792 o The RepaintManager has been reworked for more efficient 14793 painting, especially for large GUIs. 14794 o The layout manager OverlayLayout has been implemented, 14795 the BoxLayout has been rewritten to make use of the 14796 SizeRequirements utility class and caching for more 14797 efficient layout. 14798 o Improved accessibility support. 14799 o Significant progress has been made in the implementation 14800 of the javax.swing.plaf.metal package, with most UI 14801 delegates in a working state now. Please test this with 14802 your own applications and provide feedback that will help 14803 us to improve this package. 14804 o The GUI demo (gnu.classpath.examples.swing.Demo) has been 14805 extended to highlight various features in our Free Swing 14806 implementation. And it includes a look and feel switcher 14807 for Metal (default), Ocean and GNU themes. 14808 o The javax.swing.plaf.multi package is now implemented. 14809 o Editing and several key actions for JTree and JTable were 14810 implemented. 14811 o Lots of icons and look and feel improvements for Free 14812 Swing basic and metal themes were added. Try running the 14813 GNU Classpath Swing Demo in examples 14814 (gnu.classpath.examples.swing.Demo) with: 14815 -Dswing.defaultlaf=javax.swing.plaf.basic.BasicLookAndFee 14816 l or 14817 -Dswing.defaultlaf=javax.swing.plaf.metal.MetalLookAndFee 14818 l 14819 o Start of styled text capabilites for java.swing.text. 14820 o DefaultMutableTreeNode pre-order, post-order, depth-first 14821 and breadth-first traversal enumerations implemented. 14822 o JInternalFrame colors and titlebar draw properly. 14823 o JTree is working up to par (icons, selection and keyboard 14824 traversal). 14825 o JMenus were made more compatible in visual and 14826 programmatic behavior. 14827 o JTable changeSelection and multiple selections 14828 implemented. 14829 o JButton and JToggleButton change states work properly 14830 now. 14831 o JFileChooser fixes. 14832 o revalidate() and repaint() fixes which make Free Swing 14833 much more responsive. 14834 o MetalIconFactory implemented. 14835 o Free Swing Top-Level Compatibility. JFrame, JDialog, 14836 JApplet, JInternalFrame, and JWindow are now 1.5 14837 compatible in the sense that you can call add() and 14838 setLayout() directly on them, which will have the same 14839 effect as calling getContentPane().add() and 14840 getContentPane().setLayout(). 14841 o The JTree interface has been completed. JTrees now 14842 recognizes mouse clicks and selections work. 14843 o BoxLayout works properly now. 14844 o Fixed GrayFilter to actually work. 14845 o Metal SplitPane implemented. 14846 o Lots of Free Swing text and editor stuff work now. 14847 + Free RMI and Corba 14848 o Andrew Watson, Vice President and Technical Director of 14849 the Object Management Group, has officially assigned us 14850 20 bit Vendor Minor Code Id: 0x47430 ("GC") that will 14851 mark remote classpath-specific system exceptions. 14852 Obtaining the VMCID means that GNU Classpath now is a 14853 recogniseable type of node in a highly interoperable 14854 CORBA world. 14855 o GNU Classpath now includes the first working draft to 14856 support the RMI over IIOP protocol. The current 14857 implementation is capable of remote invocations, 14858 transferring various Serializables and Externalizables 14859 via RMI-IIOP protocol. It can flatten graphs and, at 14860 least for the simple cases, is interoperable with 1.5 14861 JDKs. 14862 o org.omg.PortableInterceptor and related functionality in 14863 other packages is now implemented: 14864 # The sever and client interceptors work as required 14865 since 1.4. 14866 # The IOR interceptor works as needed for 1.5. 14867 o The org.omg.DynamicAny package is completed and passes 14868 the prepared tests. 14869 o The Portable Object Adapter should now support the output 14870 of the recent IDL to java compilers. These compilers now 14871 generate servants and not CORBA objects as before, making 14872 the output depend on the existing POA implementation. 14873 Completing POA means that such code can already be tried 14874 to run on Classpath. Our POA is tested for the following 14875 usager scenarios: 14876 # POA converts servant to the CORBA object. 14877 # Servant provides to the CORBA object. 14878 # POA activates new CORBA object with the given Object 14879 Id (byte array) that is later accessible for the 14880 servant. 14881 # During the first call, the ServantActivator provides 14882 servant for this and all subsequent calls on the 14883 current object. 14884 # During each call, the ServantLocator provides 14885 servant for this call only. 14886 # ServantLocator or ServantActivator forwards call to 14887 another server. 14888 # POA has a single servant, responsible for all 14889 objects. 14890 # POA has a default servant, but some objects are 14891 explicitly connected to they specific servants. 14892 The POA is verified using tests from the former 14893 cost.omg.org. 14894 o The CORBA implementation is now a working prototype that 14895 should support features up to 1.3 inclusive. We invite 14896 groups writing CORBA dependent applications to try 14897 Classpath implementation, reporting any possible bugs. 14898 The CORBA prototype is interoperable with Sun's 14899 implementation v 1.4, transferring object references, 14900 primitive types, narrow and wide strings, arrays, 14901 structures, trees, abstract interfaces and value types 14902 (feature of CORBA 2.3) between these two platforms. 14903 Remote exceptions are transferred and handled correctly. 14904 The stringified object references (IORs) from various 14905 sources are parsed as required. The transient (for 14906 current session) and permanent (till jre restart) 14907 redirections work. Both Little and Big Endian encoded 14908 messages are accepted. The implementation is verified 14909 using tests from the former cost.omg.org. The current 14910 release includes working examples (see the examples 14911 directory), demonstrating the client-server 14912 communication, using either CORBA Request or IDL-based 14913 stub (usually generated by a IDL to java compiler). These 14914 examples also show how to use the Classpath CORBA naming 14915 service. The IDL to java compiler is not yet written, but 14916 as our library must be compatible, it naturally accepts 14917 the output of other idlj implementations. 14918 + Misc 14919 o Updated TimeZone data against Olson tzdata2005l. 14920 o Make zip and jar packages UTF-8 clean. 14921 o "native" code builds and compiles (warning free) on 14922 Darwin and Solaris. 14923 o java.util.logging.FileHandler now rotates files. 14924 o Start of a generic JDWP framework in gnu/classpath/jdwp. 14925 This is unfinished, but feedback (at classpath (a] gnu.org) 14926 from runtime hackers is greatly appreciated. Although 14927 most of the work is currently being done around gcj/gij 14928 we want this framework to be as VM neutral as possible. 14929 Early design is described in: 14930 [2]https://gcc.gnu.org/ml/java/2005-05/msg00260.html 14931 o QT4 AWT peers, enable by giving configure 14932 --enable-qt-peer. Included, but not ready for production 14933 yet. They are explicitly disabled and not supported. But 14934 if you want to help with the development of these new 14935 features we are interested in feedback. You will have to 14936 explicitly enable them to try them out (and they will 14937 most likely contain bugs). 14938 o Documentation fixes all over the place. See 14939 [3]https://developer.classpath.org/doc/ 14940 14941 New Targets and Target Specific Improvements 14942 14943 IA-32/x86-64 14944 14945 * The x86-64 medium model (that allows building applications whose 14946 data segment exceeds 4GB) was redesigned to match latest ABI draft. 14947 New implementation split large datastructures into separate segment 14948 improving performance of accesses to small datastructures and also 14949 allows linking of small model libraries into medium model programs 14950 as long as the libraries are not accessing the large datastructures 14951 directly. Medium model is also supported in position independent 14952 code now. 14953 The ABI change results in partial incompatibility among medium 14954 model objects. Linking medium model libraries (or objects) compiled 14955 with new compiler into medium model program compiled with older 14956 will likely result in exceeding ranges of relocations. 14957 Binutils 2.16.91 or newer are required for compiling medium model 14958 now. 14959 14960 RS6000 (POWER/PowerPC) 14961 14962 * The AltiVec vector primitives in <altivec.h> are now implemented in 14963 a way that puts a smaller burden on the preprocessor, instead 14964 processing the "overloading" in the front ends. This should benefit 14965 compilation speed on AltiVec vector code. 14966 * AltiVec initializers now are generated more efficiently. 14967 * The popcountb instruction available on POWER5 now is generated. 14968 * The floating point round to integer instructions available on 14969 POWER5+ now is generated. 14970 * Floating point divides can be synthesized using the floating point 14971 reciprocal estimate instructions. 14972 * Double precision floating point constants are initialized as single 14973 precision values if they can be represented exactly. 14974 14975 S/390, zSeries and System z9 14976 14977 * Support for the IBM System z9 109 processor has been added. When 14978 using the -march=z9-109 option, the compiler will generate code 14979 making use of instructions provided by the extended immediate 14980 facility. 14981 * Support for 128-bit IEEE floating point has been added. When using 14982 the -mlong-double-128 option, the compiler will map the long double 14983 data type to 128-bit IEEE floating point. Using this option 14984 constitutes an ABI change, and requires glibc support. 14985 * Various changes to improve performance of generated code have been 14986 implemented, including: 14987 + In functions that do not require a literal pool, register %r13 14988 (which is traditionally reserved as literal pool pointer), can 14989 now be freely used for other purposes by the compiler. 14990 + More precise tracking of register use allows the compiler to 14991 generate more efficient function prolog and epilog code in 14992 certain cases. 14993 + The SEARCH STRING, COMPARE LOGICAL STRING, and MOVE STRING 14994 instructions are now used to implement C string functions. 14995 + The MOVE CHARACTER instruction with single byte overlap is now 14996 used to implement the memset function with non-zero fill byte. 14997 + The LOAD ZERO instructions are now used where appropriate. 14998 + The INSERT CHARACTERS UNDER MASK, STORE CHARACTERS UNDER MASK, 14999 and INSERT IMMEDIATE instructions are now used more frequently 15000 to optimize bitfield operations. 15001 + The BRANCH ON COUNT instruction is now used more frequently. 15002 In particular, the fact that a loop contains a subroutine call 15003 no longer prevents the compiler from using this instruction. 15004 + The compiler is now aware that all shift and rotate 15005 instructions implicitly truncate the shift count to six bits. 15006 * Back-end support for the following generic features has been 15007 implemented: 15008 + The full set of [4]built-in functions for atomic memory 15009 access. 15010 + The -fstack-protector feature. 15011 + The optimization pass avoiding unnecessary stores of incoming 15012 argument registers in functions with variable argument list. 15013 15014 SPARC 15015 15016 * The default code model in 64-bit mode has been changed from 15017 Medium/Anywhere to Medium/Middle on Solaris. 15018 * TLS support is disabled by default on Solaris prior to release 10. 15019 It can be enabled on TLS-capable Solaris 9 versions (4/04 release 15020 and later) by specifying --enable-tls at configure time. 15021 15022 MorphoSys 15023 15024 * Support has been added for this new architecture. 15025 15026 Obsolete Systems 15027 15028 Documentation improvements 15029 15030 Other significant improvements 15031 15032 * GCC can now emit code for protecting applications from 15033 stack-smashing attacks. The protection is realized by buffer 15034 overflow detection and reordering of stack variables to avoid 15035 pointer corruption. 15036 * Some built-in functions have been fortified to protect them against 15037 various buffer overflow (and format string) vulnerabilities. 15038 Compared to the mudflap bounds checking feature, the safe builtins 15039 have far smaller overhead. This means that programs built using 15040 safe builtins should not experience any measurable slowdown. 15041 15042 GCC 4.1.2 15043 15044 This is the [5]list of problem reports (PRs) from GCC's bug tracking 15045 system that are known to be fixed in the 4.1.2 release. This list might 15046 not be complete (that is, it is possible that some PRs that have been 15047 fixed are not listed here). 15048 15049 When generating code for a shared library, GCC now recognizes that 15050 global functions may be replaced when the program runs. Therefore, it 15051 is now more conservative in deducing information from the bodies of 15052 functions. For example, in this example: 15053 void f() {} 15054 void g() { 15055 try { f(); } 15056 catch (...) { 15057 cout << "Exception"; 15058 } 15059 } 15060 15061 G++ would previously have optimized away the catch clause, since it 15062 would have concluded that f cannot throw exceptions. Because users may 15063 replace f with another function in the main body of the program, this 15064 optimization is unsafe, and is no longer performed. If you wish G++ to 15065 continue to optimize as before, you must add a throw() clause to the 15066 declaration of f to make clear that it does not throw exceptions. 15067 15068 15069 For questions related to the use of GCC, please consult these web 15070 pages and the [6]GCC manuals. If that fails, the 15071 [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15072 web pages and the development of GCC are welcome on our developer 15073 list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives. 15074 15075 Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and 15076 distribution of this entire article is permitted in any medium, 15077 provided this notice is preserved. 15078 15079 These pages are [11]maintained by the GCC team. Last modified 15080 2022-10-26. 15081 15082 References 15083 15084 1. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 15085 2. https://gcc.gnu.org/ml/java/2005-05/msg00260.html 15086 3. https://developer.classpath.org/doc/ 15087 4. https://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html 15088 5. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.1.2 15089 6. https://gcc.gnu.org/onlinedocs/ 15090 7. mailto:gcc-help (a] gcc.gnu.org 15091 8. mailto:gcc (a] gcc.gnu.org 15092 9. https://gcc.gnu.org/lists.html 15093 10. https://www.fsf.org/ 15094 11. https://gcc.gnu.org/about.html 15095 ====================================================================== 15096 http://gcc.gnu.org/gcc-4.0/index.html 15097 15098 GCC 4.0 Release Series 15099 15100 (This release series is no longer supported.) 15101 15102 January 31, 2007 15103 15104 The [1]GNU project and the GCC developers are pleased to announce the 15105 release of GCC 4.0.4. 15106 15107 This release is a bug-fix release, containing fixes for regressions in 15108 GCC 4.0.3 relative to previous releases of GCC. 15109 15110 Release History 15111 15112 GCC 4.0.4 15113 January 31, 2007 ([2]changes) 15114 15115 GCC 4.0.3 15116 March 10, 2006 ([3]changes) 15117 15118 GCC 4.0.2 15119 September 28, 2005 ([4]changes) 15120 15121 GCC 4.0.1 15122 July 7, 2005 ([5]changes) 15123 15124 GCC 4.0.0 15125 April 20, 2005 ([6]changes) 15126 15127 References and Acknowledgements 15128 15129 GCC used to stand for the GNU C Compiler, but since the compiler 15130 supports several other languages aside from C, it now stands for the 15131 GNU Compiler Collection. 15132 15133 A list of [7]successful builds is updated as new information becomes 15134 available. 15135 15136 The GCC developers would like to thank the numerous people that have 15137 contributed new features, improvements, bug fixes, and other changes as 15138 well as test results to GCC. This [8]amazing group of volunteers is 15139 what makes GCC successful. 15140 15141 For additional information about GCC please refer to the [9]GCC project 15142 web site or contact the [10]GCC development mailing list. 15143 15144 To obtain GCC please use [11]our mirror sites, or [12]our version 15145 control system. 15146 15147 15148 For questions related to the use of GCC, please consult these web 15149 pages and the [13]GCC manuals. If that fails, the 15150 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15151 web pages and the development of GCC are welcome on our developer 15152 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 15153 archives. 15154 15155 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 15156 distribution of this entire article is permitted in any medium, 15157 provided this notice is preserved. 15158 15159 These pages are [18]maintained by the GCC team. Last modified 15160 2022-10-26. 15161 15162 References 15163 15164 1. http://www.gnu.org/ 15165 2. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 15166 3. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.3 15167 4. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.2 15168 5. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.1 15169 6. http://gcc.gnu.org/gcc-4.0/changes.html 15170 7. http://gcc.gnu.org/gcc-4.0/buildstat.html 15171 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 15172 9. http://gcc.gnu.org/index.html 15173 10. mailto:gcc (a] gcc.gnu.org 15174 11. http://gcc.gnu.org/mirrors.html 15175 12. http://gcc.gnu.org/git.html 15176 13. https://gcc.gnu.org/onlinedocs/ 15177 14. mailto:gcc-help (a] gcc.gnu.org 15178 15. mailto:gcc (a] gcc.gnu.org 15179 16. https://gcc.gnu.org/lists.html 15180 17. https://www.fsf.org/ 15181 18. https://gcc.gnu.org/about.html 15182 ====================================================================== 15183 http://gcc.gnu.org/gcc-4.0/changes.html 15184 15185 GCC 4.0 Release Series 15186 Changes, New Features, and Fixes 15187 15188 The latest release in the 4.0 release series is [1]GCC 4.0.4. 15189 15190 Caveats 15191 15192 * GCC now generates location lists by default when compiling with 15193 debug info and optimization. 15194 + GDB 6.0 and older crashes when it sees location lists. GDB 6.1 15195 or later is needed to debug binaries containing location 15196 lists. 15197 + When you are trying to view a value of a variable in a part of 15198 a function where it has no location (for example when the 15199 variable is no longer used and thus its location was used for 15200 something else) GDB will say that it is not available. 15201 You can disable generating location lists by -fno-var-tracking. 15202 * GCC no longer accepts the -fwritable-strings option. Use named 15203 character arrays when you need a writable string. 15204 * The options -freduce-all-givs and -fmove-all-movables have been 15205 discontinued. They were used to circumvent a shortcoming in the 15206 heuristics of the old loop optimization code with respect to common 15207 Fortran constructs. The new (tree) loop optimizer works differently 15208 and doesn't need those work-arounds. 15209 * The graph-coloring register allocator, formerly enabled by the 15210 option -fnew-ra, has been discontinued. 15211 * -I- has been deprecated. -iquote is meant to replace the need for 15212 this option. 15213 * The MIPS -membedded-pic and -mrnames options have been removed. 15214 * All MIPS targets now require the GNU assembler. In particular, IRIX 15215 configurations can no longer use the MIPSpro assemblers, although 15216 they do still support the MIPSpro linkers. 15217 * The SPARC option -mflat has been removed. 15218 * English-language diagnostic messages will now use Unicode quotation 15219 marks in UTF-8 locales. (Non-English messages already used the 15220 quotes appropriate for the language in previous releases.) If your 15221 terminal does not support UTF-8 but you are using a UTF-8 locale 15222 (such locales are the default on many GNU/Linux systems) then you 15223 should set LC_CTYPE=C in the environment to disable that locale. 15224 Programs that parse diagnostics and expect plain ASCII 15225 English-language messages should set LC_ALL=C. See [2]Markus Kuhn's 15226 explanation of Unicode quotation marks for more information. 15227 * The specs file is no longer installed on most platforms. Most users 15228 will be totally unaffected. However, if you are accustomed to 15229 editing the specs file yourself, you will now have to use the 15230 -dumpspecs option to generate the specs file, and then edit the 15231 resulting file. 15232 15233 General Optimizer Improvements 15234 15235 * The [3]tree ssa branch has been merged. This merge has brought in a 15236 completely new optimization framework based on a higher level 15237 intermediate representation than the existing RTL representation. 15238 Numerous new code transformations based on the new framework are 15239 available in GCC 4.0, including: 15240 + Scalar replacement of aggregates 15241 + Constant propagation 15242 + Value range propagation 15243 + Partial redundancy elimination 15244 + Load and store motion 15245 + Strength reduction 15246 + Dead store elimination 15247 + Dead and unreachable code elimination 15248 + [4]Autovectorization 15249 + Loop interchange 15250 + Tail recursion by accumulation 15251 Many of these passes outperform their counterparts from previous 15252 GCC releases. 15253 * [5]Swing Modulo Scheduling (SMS). An RTL level instruction 15254 scheduling optimization intended for loops that perform heavy 15255 computations. 15256 15257 New Languages and Language specific improvements 15258 15259 C family 15260 15261 * The sentinel attribute has been added to GCC. This function 15262 attribute allows GCC to warn when variadic functions such as execl 15263 are not NULL terminated. See the GCC manual for a complete 15264 description of its behavior. 15265 * Given __attribute__((alias("target"))) it is now an error if target 15266 is not a symbol, defined in the same translation unit. This also 15267 applies to aliases created by #pragma weak alias=target. This is 15268 because it's meaningless to define an alias to an undefined symbol. 15269 On Solaris, the native assembler would have caught this error, but 15270 GNU as does not. 15271 15272 C and Objective-C 15273 15274 * The -Wstrict-aliasing=2 option has been added. This warning catches 15275 all unsafe cases, but it may also give a warning for some cases 15276 that are safe. 15277 * The cast-as-lvalue, conditional-expression-as-lvalue and 15278 compound-expression-as-lvalue extensions, which were deprecated in 15279 3.3.4 and 3.4, have been removed. 15280 * The -fwritable-strings option, which was deprecated in 3.4, has 15281 been removed. 15282 * #pragma pack() semantics have been brought closer to those used by 15283 other compilers. This also applies to C++. 15284 * Taking the address of a variable with register storage is invalid 15285 in C. GCC now issues an error instead of a warning. 15286 * Arrays of incomplete element type are invalid in C. GCC now issues 15287 an error for such arrays. Declarations such as extern struct s x[]; 15288 (where struct s has not been defined) can be moved after the 15289 definition of struct s. Function parameters declared as arrays of 15290 incomplete type can instead be declared as pointers. 15291 15292 C++ 15293 15294 * When compiling without optimizations (-O0), the C++ front end is 15295 much faster than in any previous versions of GCC. Independent 15296 testers have measured speed-ups up to 25% in real-world production 15297 code, compared to the 3.4 family (which was already the fastest 15298 version to date). Upgrading from older versions might show even 15299 bigger improvements. 15300 * ELF visibility attributes can now be applied to a class type, so 15301 that it affects every member function of a class at once, without 15302 having to specify each individually: 15303 class __attribute__ ((visibility("hidden"))) Foo 15304 { 15305 int foo1(); 15306 void foo2(); 15307 }; 15308 The syntax is deliberately similar to the __declspec() system used 15309 by Microsoft Windows based compilers, allowing cross-platform 15310 projects to easily reuse their existing macro system for denoting 15311 exports and imports. By explicitly marking internal classes never 15312 used outside a binary as hidden, one can completely avoid PLT 15313 indirection overheads during their usage by the compiler. You can 15314 find out more about the advantages of this at 15315 [6]https://www.akkadia.org/drepper/dsohowto.pdf 15316 * The -fvisibility-inlines-hidden option has been added which marks 15317 all inlineable functions as having hidden ELF visibility, thus 15318 removing their symbol and typeinfo from the exported symbol table 15319 of the output ELF binary. Using this option can reduce the exported 15320 symbol count of template-heavy code by up to 40% with no code 15321 change at all, thus notably improving link and load times for the 15322 binary as well as a reduction in size of up to 10%. Also, check the 15323 new [7]-fvisibility option. 15324 * The compiler now uses the library interface specified by the [8]C++ 15325 ABI for thread-safe initialization of function-scope static 15326 variables. Most users should leave this alone, but embedded 15327 programmers may want to disable this by specifying 15328 -fno-threadsafe-statics for a small savings in code size. 15329 * Taking the address of an explicit register variable is no longer 15330 supported. Note that C++ allows taking the address of variables 15331 with register storage so this will continue to compile with a 15332 warning. For example, assuming that r0 is a machine register: 15333 register int foo asm ("r0"); 15334 register int bar; 15335 &foo; // error, no longer accepted 15336 &bar; // OK, with a warning 15337 * G++ has an undocumented extension to virtual function covariancy 15338 rules that allowed the overrider to return a type that was 15339 implicitly convertable to the overridden function's return type. 15340 For instance a function returning void * could be overridden by a 15341 function returning T *. This is now deprecated and will be removed 15342 in a future release. 15343 * The G++ minimum and maximum operators (<? and >?) and their 15344 compound forms (<?=) and >?=) have been deprecated and will be 15345 removed in a future version. Code using these operators should be 15346 modified to use std::min and std::max instead. 15347 * Declaration of nested classes of class templates as friends are 15348 supported: 15349 template <typename T> struct A { 15350 class B {}; 15351 }; 15352 class C { 15353 template <typename T> friend class A<T>::B; 15354 }; 15355 This complements the feature member functions of class templates as 15356 friends introduced in GCC 3.4.0. 15357 * When declaring a friend class using an unqualified name, classes 15358 outside the innermost non-class scope are not searched: 15359 class A; 15360 namespace N { 15361 class B { 15362 friend class A; // Refer to N::A which has not been declared yet 15363 // because name outside namespace N are not searched 15364 friend class ::A; // Refer to ::A 15365 }; 15366 } 15367 Hiding the friend name until declaration is still not implemented. 15368 * Friends of classes defined outside their namespace are correctly 15369 handled: 15370 namespace N { 15371 class A; 15372 } 15373 class N::A { 15374 friend class B; // Refer to N::B in GCC 4.0.0 15375 // but ::B in earlier versions of GCC 15376 }; 15377 15378 Runtime Library (libstdc++) 15379 15380 * Optimization work: 15381 + Added efficient specializations of istream functions for char 15382 and wchar_t. 15383 + Further performance tuning of strings, in particular wrt 15384 single-char append and getline. 15385 + iter_swap - and therefore most of the mutating algorithms - 15386 now makes an unqualified call to swap when the value_type of 15387 the two iterators is the same. 15388 * A large subset of the features in Technical Report 1 (TR1 for 15389 short) is experimentally delivered (i.e., no guarantees about the 15390 implementation are provided. In particular it is not promised that 15391 the library will remain link-compatible when code using TR1 is 15392 used): 15393 + General utilities such as reference_wrapper and shared_ptr. 15394 + Function objects, i.e., result_of, mem_fn, bind, function. 15395 + Support for metaprogramming. 15396 + New containers such as tuple, array, unordered_set, 15397 unordered_map, unordered_multiset, unordered_multimap. 15398 * As usual, many bugs have been fixed and LWG resolutions implemented 15399 for the first time (e.g., DR 409). 15400 15401 Java 15402 15403 * In order to prevent naming conflicts with other implementations of 15404 these tools, some GCJ binaries have been renamed: 15405 + rmic is now grmic, 15406 + rmiregistry is now grmiregistry, and 15407 + jar is now fastjar. 15408 In particular, these names were problematic for the jpackage.org 15409 packaging conventions which install symlinks in /usr/bin that point 15410 to the preferred versions of these tools. 15411 * The -findirect-dispatch argument to the compiler now works and 15412 generates code following a new "binary compatibility" ABI. Code 15413 compiled this way follows the binary compatibility rules of the 15414 Java Language Specification. 15415 * libgcj now has support for using GCJ as a JIT, using the 15416 gnu.gcj.jit family of system properties. 15417 * libgcj can now find a shared library corresponding to the bytecode 15418 representation of a class. See the documentation for the new 15419 gcj-dbtool program, and the new gnu.gcj.precompiled.db.path system 15420 property. 15421 * There have been many improvements to the class library. Here are 15422 some highlights: 15423 + Much more of AWT and Swing exist. 15424 + Many new packages and classes were added, including 15425 java.util.regex, java.net.URI, javax.crypto, 15426 javax.crypto.interfaces, javax.crypto.spec, javax.net, 15427 javax.net.ssl, javax.security.auth, 15428 javax.security.auth.callback, javax.security.auth.login, 15429 javax.security.auth.x500, javax.security.sasl, org.ietf.jgss, 15430 javax.imageio, javax.imageio.event, javax.imageio.spi, 15431 javax.print, javax.print.attribute, 15432 javax.print.attribute.standard, javax.print.event, and 15433 javax.xml 15434 + Updated SAX and DOM, and imported GNU JAXP 15435 15436 Fortran 15437 15438 * A new [9]Fortran front end has replaced the aging GNU Fortran 77 15439 front end. The new front end supports Fortran 90 and Fortran 95. It 15440 may not yet be as stable as the old Fortran front end. 15441 15442 Ada 15443 15444 * Ada (with tasking and Zero Cost Exceptions) is now available on 15445 many more targets, including but not limited to: alpha-linux, 15446 hppa-hpux, hppa-linux, powerpc-darwin, powerpc-linux, s390-linux, 15447 s390x-linux, sparc-linux. 15448 * Some of the new Ada 2005 features are now implemented like 15449 Wide_Wide_Character and Ada.Containers. 15450 * Many bugs have been fixed, tools and documentation improved. 15451 * To compile Ada from the sources, install an older working Ada 15452 compiler and then use --enable-languages=ada at configuration time, 15453 since the Ada front end is not currently activated by default. See 15454 the [10]Installing GCC for details. 15455 15456 New Targets and Target Specific Improvements 15457 15458 H8/300 15459 15460 * The frame layout has changed. In the new layout, the prologue of a 15461 function first saves registers and then allocate space for locals, 15462 resulting in an 1% improvement on code size. 15463 15464 IA-32/x86-64 (AMD64) 15465 15466 * The acos, asin, drem, exp10, exp2, expm1, fmod, ilogb, log10, 15467 log1p, log2, logb and tan mathematical builtins (and their float 15468 and long double variants) are now implemented as inline x87 15469 intrinsics when using -ffast-math. 15470 * The ceil, floor, nearbyint, rint and trunc mathematical builtins 15471 (and their float and long double variants) are now implemented as 15472 inline x87 intrinsics when using -ffast-math. 15473 * The x87's fsincos instruction is now used automatically with 15474 -ffast-math when calculating both the sin and cos of the same 15475 argument. 15476 * Instruction selection for multiplication and division by constants 15477 has been improved. 15478 15479 IA-64 15480 15481 * Floating point division, integer division and sqrt are now inlined, 15482 resulting in significant performance improvements on some codes. 15483 15484 MIPS 15485 15486 * Division by zero checks now use conditional traps if the target 15487 processor supports them. This decreases code size by one word per 15488 division operation. The old behavior (branch and break) can be 15489 obtained either at configure time by passing --with-divide=breaks 15490 to configure or at runtime by passing -mdivide-breaks to GCC. 15491 * Support for MIPS64 paired-single instructions has been added. It is 15492 enabled by -mpaired-single and can be accessed using both the 15493 target-independent vector extensions and new MIPS-specific built-in 15494 functions. 15495 * Support for the MIPS-3D ASE has been added. It is enabled by 15496 -mips3d and provides new MIPS-3D-specific built-in functions. 15497 * The -mexplicit-relocs option now supports static n64 code (as is 15498 used, for example, in 64-bit linux kernels). -mexplicit-relocs 15499 should now be feature-complete and is enabled by default when GCC 15500 is configured to use a compatible assembler. 15501 * Support for the NEC VR4130 series has been added. This support 15502 includes the use of VR-specific instructions and a new VR4130 15503 scheduler. Full VR4130 support can be selected with -march=vr4130 15504 while code for any ISA can be tuned for the VR4130 using 15505 -mtune=vr4130. There is also a new -mvr4130-align option that 15506 produces better schedules at the cost of increased code size. 15507 * Support for the Broadcom SB-1 has been extended. There is now an 15508 SB-1 scheduler as well as support for the SB-1-specific 15509 paired-single instructions. Full SB-1 support can be selected with 15510 -march=sb1 while code for any ISA can be optimized for the SB-1 15511 using -mtune=sb1. 15512 * The compiler can now work around errata in R4000, R4400, VR4120 and 15513 VR4130 processors. These workarounds are enabled by -mfix-r4000, 15514 -mfix-r4400, -mfix-vr4120 and -mfix-vr4130 respectively. The VR4120 15515 and VR4130 workarounds need binutils 2.16 or above. 15516 * IRIX shared libraries are now installed into the standard library 15517 directories: o32 libraries go into lib/, n32 libraries go into 15518 lib32/ and n64 libraries go into lib64/. 15519 * The compiler supports a new -msym32 option. It can be used to 15520 optimize n64 code in which all symbols are known to have 32-bit 15521 values. 15522 15523 S/390 and zSeries 15524 15525 * New command-line options help to generate code intended to run in 15526 an environment where stack space is restricted, e.g. Linux kernel 15527 code: 15528 + -mwarn-framesize and -mwarn-dynamicstack trigger compile-time 15529 warnings for single functions that require large or dynamic 15530 stack frames. 15531 + -mstack-size and -mstack-guard generate code that checks for 15532 stack overflow at run time. 15533 + -mpacked-stack generates code that reduces the stack frame 15534 size of many functions by reusing unneeded parts of the stack 15535 bias area. 15536 * The -msoft-float option now ensures that generated code never 15537 accesses floating point registers. 15538 * The s390x-ibm-tpf target now fully supports C++, including 15539 exceptions and threads. 15540 * Various changes to improve performance of the generated code have 15541 been implemented, including: 15542 + GCC now uses sibling calls where possible. 15543 + Condition code handling has been optimized, allowing GCC to 15544 omit redundant comparisons in certain cases. 15545 + The cost function guiding many optimizations has been refined 15546 to more accurately represent the z900 and z990 processors. 15547 + The ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL WITH BORROW 15548 instructions are now used to avoid conditional branches in 15549 certain cases. 15550 + The back end now uses the LEGITIMIZE_RELOAD_ADDRESS feature to 15551 optimize address arithmetic required to access large stack 15552 frames. 15553 + GCC now makes more efficient use of memory-to-memory type 15554 instructions (MVC, CLC, ...). 15555 + More precise tracking of special register use allows better 15556 instruction scheduling, in particular of the function prologue 15557 and epilogue sequences. 15558 + The Java front end now generates inline code to implement 15559 integer division, instead of calling library routines. 15560 15561 SPARC 15562 15563 * The options -mv8, -msparclite, -mcypress, -msupersparc, -mf930 and 15564 -mf934 have been removed. They have been replaced with -mcpu=xxx. 15565 * The internal model used to estimate the relative cost of each 15566 instruction has been updated. It is expected to give better results 15567 on recent UltraSPARC processors. 15568 * Code generation for function prologues and epilogues has been 15569 improved, resulting in better scheduling and allowing multiple exit 15570 points in functions. 15571 * Support for Sun's Visual Instruction Set (VIS) has been enhanced. 15572 It is enabled by -mvis and provides new built-in functions for VIS 15573 instructions on UltraSPARC processors. 15574 * The option -mapp-regs has been turned on by default on Solaris too. 15575 15576 NetWare 15577 15578 * Novell NetWare (on ix86, no other hardware platform was ever really 15579 supported by this OS) has been re-enabled and the ABI supported by 15580 GCC has been brought into sync with that of MetroWerks CodeWarrior 15581 (the ABI previously supported was that of some Unix systems, which 15582 NetWare never tried to support). 15583 15584 Obsolete Systems 15585 15586 Support for a number of older systems has been declared obsolete in GCC 15587 4.0. Unless there is activity to revive them, the next release of GCC 15588 will have their sources permanently removed. 15589 15590 All GCC ports for the following processor architectures have been 15591 declared obsolete: 15592 * Intel i860 15593 * Ubicom IP2022 15594 * National Semiconductor NS32K (ns32k) 15595 * Texas Instruments TMS320C[34]x 15596 15597 Also, those for some individual systems have been obsoleted: 15598 * SPARC family 15599 + SPARClite-based systems (sparclite-*-coff, sparclite-*-elf, 15600 sparc86x-*-elf) 15601 + OpenBSD 32-bit (sparc-*-openbsd*) 15602 15603 Documentation improvements 15604 15605 Other significant improvements 15606 15607 * Location lists are now generated by default when compiling with 15608 debug info and optimization. Location lists provide more accurate 15609 debug info about locations of variables and they allow debugging 15610 code compiled with -fomit-frame-pointer. 15611 * The -fvisibility option has been added which allows the default ELF 15612 visibility of all symbols to be set per compilation and the new 15613 #pragma GCC visibility preprocessor command allows the setting of 15614 default ELF visibility for a region of code. Using 15615 -fvisibility=hidden especially in combination with the new 15616 -fvisibility-inlines-hidden can yield substantial improvements in 15617 output binary quality including avoiding PLT indirection overheads, 15618 reduction of the exported symbol count by up to 60% (with resultant 15619 improvements to link and load times), better scope for the 15620 optimizer to improve code and up to a 20% reduction in binary size. 15621 Using these options correctly yields a binary with a similar symbol 15622 count to a Windows DLL. 15623 Perhaps more importantly, this new feature finally allows (with 15624 careful planning) complete avoidance of symbol clashes when 15625 manually loading shared objects with RTLD_GLOBAL, thus finally 15626 solving problems many projects such as python were forced to use 15627 RTLD_LOCAL for (with its resulting issues for C++ correctness). You 15628 can find more information about using these options at 15629 [11]https://gcc.gnu.org/wiki/Visibility. 15630 __________________________________________________________________ 15631 15632 GCC 4.0.1 15633 15634 This is the [12]list of problem reports (PRs) from GCC's bug tracking 15635 system that are known to be fixed in the 4.0.1 release. This list might 15636 not be complete (that is, it is possible that some PRs that have been 15637 fixed are not listed here). 15638 15639 GCC 4.0.2 15640 15641 This is the [13]list of problem reports (PRs) from GCC's bug tracking 15642 system that are known to be fixed in the 4.0.2 release. This list might 15643 not be complete (that is, it is possible that some PRs that have been 15644 fixed are not listed here). 15645 15646 Unfortunately, due to a release engineering failure, this release has a 15647 regression on Solaris that will affect some C++ programs. We suggest 15648 that Solaris users apply a [14]patch that corrects the problem. Users 15649 who do not wish to apply the patch should explicitly link C++ programs 15650 with the -pthreads option, even if they do not use threads. This 15651 problem has been corrected in the current 4.0 branch sources and will 15652 not be present in GCC 4.0.3. 15653 15654 GCC 4.0.3 15655 15656 Starting with this release, the function getcontext is recognized by 15657 the compiler as having the same semantics as the setjmp function. In 15658 particular, the compiler will ensure that all registers are dead before 15659 calling such a function and will emit a warning about the variables 15660 that may be clobbered after the second return from the function. 15661 15662 GCC 4.0.4 15663 15664 This is the [15]list of problem reports (PRs) from GCC's bug tracking 15665 system that are known to be fixed in the 4.0.4 release. This list might 15666 not be complete (that is, it is possible that some PRs that have been 15667 fixed are not listed here). 15668 15669 The 4.0.4 release is provided for those that require a high degree of 15670 binary compatibility with previous 4.0.x releases. For most users, the 15671 GCC team recommends that version 4.1.1 or later be used instead." 15672 15673 15674 For questions related to the use of GCC, please consult these web 15675 pages and the [16]GCC manuals. If that fails, the 15676 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15677 web pages and the development of GCC are welcome on our developer 15678 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 15679 archives. 15680 15681 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 15682 distribution of this entire article is permitted in any medium, 15683 provided this notice is preserved. 15684 15685 These pages are [21]maintained by the GCC team. Last modified 15686 2022-10-26. 15687 15688 References 15689 15690 1. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 15691 2. https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html 15692 3. http://gcc.gnu.org/projects/tree-ssa/ 15693 4. http://gcc.gnu.org/projects/tree-ssa/vectorization.html 15694 5. http://gcc.gnu.org/news/sms.html 15695 6. https://www.akkadia.org/drepper/dsohowto.pdf 15696 7. http://gcc.gnu.org/gcc-4.0/changes.html#visibility 15697 8. https://itanium-cxx-abi.github.io/cxx-abi/ 15698 9. http://gcc.gnu.org/fortran/ 15699 10. https://gcc.gnu.org/install/ 15700 11. https://gcc.gnu.org/wiki/Visibility 15701 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.1 15702 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.2 15703 14. https://gcc.gnu.org/ml/gcc-cvs/2005-09/msg00984.html 15704 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.4 15705 16. https://gcc.gnu.org/onlinedocs/ 15706 17. mailto:gcc-help (a] gcc.gnu.org 15707 18. mailto:gcc (a] gcc.gnu.org 15708 19. https://gcc.gnu.org/lists.html 15709 20. https://www.fsf.org/ 15710 21. https://gcc.gnu.org/about.html 15711 ====================================================================== 15712 http://gcc.gnu.org/gcc-3.4/index.html 15713 15714 GCC 3.4 Release Series 15715 15716 (This release series is no longer supported.) 15717 15718 May 26, 2006 15719 15720 The [1]GNU project and the GCC developers are pleased to announce the 15721 release of GCC 3.4.6. 15722 15723 This release is a bug-fix release, containing fixes for regressions in 15724 GCC 3.4.4 relative to previous releases of GCC. This is the last of the 15725 3.4.x series. 15726 15727 The GCC 3.4 release series includes numerous [2]new features, 15728 improvements, bug fixes, and other changes, thanks to an [3]amazing 15729 group of volunteers. 15730 15731 Release History 15732 15733 GCC 3.4.6 15734 March 6, 2006 ([4]changes) 15735 15736 GCC 3.4.5 15737 November 30, 2005 ([5]changes) 15738 15739 GCC 3.4.4 15740 May 18, 2005 ([6]changes) 15741 15742 GCC 3.4.3 15743 November 4, 2004 ([7]changes) 15744 15745 GCC 3.4.2 15746 September 6, 2004 ([8]changes) 15747 15748 GCC 3.4.1 15749 July 1, 2004 ([9]changes) 15750 15751 GCC 3.4.0 15752 April 18, 2004 ([10]changes) 15753 15754 References and Acknowledgements 15755 15756 GCC used to stand for the GNU C Compiler, but since the compiler 15757 supports several other languages aside from C, it now stands for the 15758 GNU Compiler Collection. 15759 15760 A list of [11]successful builds is updated as new information becomes 15761 available. 15762 15763 The GCC developers would like to thank the numerous people that have 15764 contributed new features, improvements, bug fixes, and other changes as 15765 well as test results to GCC. This [12]amazing group of volunteers is 15766 what makes GCC successful. 15767 15768 For additional information about GCC please refer to the [13]GCC 15769 project web site or contact the [14]GCC development mailing list. 15770 15771 To obtain GCC please use [15]our mirror sites, or [16]our version 15772 control system. 15773 15774 15775 For questions related to the use of GCC, please consult these web 15776 pages and the [17]GCC manuals. If that fails, the 15777 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15778 web pages and the development of GCC are welcome on our developer 15779 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 15780 archives. 15781 15782 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 15783 distribution of this entire article is permitted in any medium, 15784 provided this notice is preserved. 15785 15786 These pages are [22]maintained by the GCC team. Last modified 15787 2022-10-26. 15788 15789 References 15790 15791 1. http://www.gnu.org/ 15792 2. http://gcc.gnu.org/gcc-3.4/changes.html 15793 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 15794 4. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6 15795 5. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.5 15796 6. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.4 15797 7. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.3 15798 8. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.2 15799 9. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.1 15800 10. http://gcc.gnu.org/gcc-3.4/changes.html 15801 11. http://gcc.gnu.org/gcc-3.4/buildstat.html 15802 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 15803 13. http://gcc.gnu.org/index.html 15804 14. mailto:gcc (a] gcc.gnu.org 15805 15. http://gcc.gnu.org/mirrors.html 15806 16. http://gcc.gnu.org/git.html 15807 17. https://gcc.gnu.org/onlinedocs/ 15808 18. mailto:gcc-help (a] gcc.gnu.org 15809 19. mailto:gcc (a] gcc.gnu.org 15810 20. https://gcc.gnu.org/lists.html 15811 21. https://www.fsf.org/ 15812 22. https://gcc.gnu.org/about.html 15813 ====================================================================== 15814 http://gcc.gnu.org/gcc-3.4/changes.html 15815 15816 GCC 3.4 Release Series 15817 Changes, New Features, and Fixes 15818 15819 The final release in the 3.4 release series is [1]GCC 3.4.6. The series 15820 is now closed. 15821 15822 GCC 3.4 has [2]many improvements in the C++ front end. Before reporting 15823 a bug, please make sure it's really GCC, and not your code, that is 15824 broken. 15825 15826 Caveats 15827 15828 * GNU Make is now required to build GCC. 15829 * With -nostdinc the preprocessor used to ignore both standard 15830 include paths and include paths contained in environment variables. 15831 It was neither documented nor intended that environment variable 15832 paths be ignored, so this has been corrected. 15833 * GCC no longer accepts the options -fvolatile, -fvolatile-global and 15834 -fvolatile-static. It is unlikely that they worked correctly in any 15835 3.x release. 15836 * GCC no longer ships <varargs.h>. Use <stdarg.h> instead. 15837 * Support for all the systems [3]obsoleted in GCC 3.3 has been 15838 removed from GCC 3.4. See below for a [4]list of systems which are 15839 obsoleted in this release. 15840 * GCC now requires an ISO C90 (ANSI C89) C compiler to build. K&R C 15841 compilers will not work. 15842 * The implementation of the [5]MIPS ABIs has changed. As a result, 15843 the code generated for certain MIPS targets will not be binary 15844 compatible with earlier releases. 15845 * In previous releases, the MIPS port had a fake "hilo" register with 15846 the user-visible name accum. This register has been removed. 15847 * The implementation of the [6]SPARC ABIs has changed. As a result, 15848 the code generated will not be binary compatible with earlier 15849 releases in certain cases. 15850 * The configure option --enable-threads=pthreads has been removed; 15851 use --enable-threads=posix instead, which should have the same 15852 effect. 15853 * Code size estimates used by inlining heuristics for C, Objective-C, 15854 C++ and Java have been redesigned significantly. As a result the 15855 parameters of -finline-insns, --param max-inline-insns-single and 15856 --param max-inline-insns-auto need to be reconsidered. 15857 * --param max-inline-slope and --param min-inline-insns have been 15858 removed; they are not needed for the new bottom-up inlining 15859 heuristics. 15860 * The new unit-at-a-time compilation scheme has several compatibility 15861 issues: 15862 + The order in which functions, variables, and top-level asm 15863 statements are emitted may have changed. Code relying on some 15864 particular ordering needs to be updated. The majority of such 15865 top-level asm statements can be replaced by section 15866 attributes. 15867 + Unreferenced static variables and functions are removed. This 15868 may result in undefined references when an asm statement 15869 refers to the variable/function directly. In that case either 15870 the variable/function shall be listed in asm statement operand 15871 or in the case of top-level asm statements the attribute used 15872 shall be used to force function/variable to be always output 15873 and considered as a possibly used by unknown code. 15874 For variables the attribute is accepted only by GCC 3.4 and 15875 newer, while for earlier versions it is sufficient to use 15876 unused to silence warnings about the variables not being 15877 referenced. To keep code portable across different GCC 15878 versions, you can use appropriate preprocessor conditionals. 15879 + Static functions now can use non-standard passing conventions 15880 that may break asm statements calling functions directly. 15881 Again the attribute used shall be used to prevent this 15882 behavior. 15883 As a temporary workaround, -fno-unit-at-a-time can be used, but 15884 this scheme may not be supported by future releases of GCC. 15885 * GCC 3.4 automatically places zero-initialized variables in the .bss 15886 section on some operating systems. Versions of GNU Emacs up to (and 15887 including) 21.3 will not work correctly when using this 15888 optimization; you can use -fno-zero-initialized-in-bss to disable 15889 it. 15890 * If GCC 3.4 is configured with --enable-threads=posix (the default 15891 on most targets that support pthreads) then _REENTRANT will be 15892 defined unconditionally by some libstdc++ headers. C++ code which 15893 relies on that macro to detect whether multi-threaded code is being 15894 compiled might change in meaning, possibly resulting in linker 15895 errors for single-threaded programs. Affected users of [7]Boost 15896 should compile single-threaded code with -DBOOST_DISABLE_THREADS. 15897 See Bugzilla for [8]more information. 15898 15899 General Optimizer Improvements 15900 15901 * Usability of the profile feedback and coverage testing has been 15902 improved. 15903 + Performance of profiled programs has been improved by faster 15904 profile merging code. 15905 + Better use of the profile feedback for optimization (loop 15906 unrolling and loop peeling). 15907 + File locking support allowing fork() calls and parallel runs 15908 of profiled programs. 15909 + Coverage file format has been redesigned. 15910 + gcov coverage tool has been improved. 15911 + make profiledbootstrap available to build a faster compiler. 15912 Experiments made on i386 hardware showed an 11% speedup on -O0 15913 and a 7.5% speedup on -O2 compilation of a [9]large C++ 15914 testcase. 15915 + New value profiling pass enabled via -fprofile-values 15916 + New value profile transformations pass enabled via -fvpt aims 15917 to optimize some code sequences by exploiting knowledge about 15918 value ranges or other properties of the operands. At the 15919 moment a conversion of expensive divisions into cheaper 15920 operations has been implemented. 15921 + New -fprofile-generate and -fprofile-use command-line options 15922 to simplify the use of profile feedback. 15923 * A new unit-at-a-time compilation scheme for C, Objective-C, C++ and 15924 Java which is enabled via -funit-at-a-time (and implied by -O2). In 15925 this scheme a whole file is parsed first and optimized later. The 15926 following basic inter-procedural optimizations are implemented: 15927 + Removal of unreachable functions and variables 15928 + Discovery of local functions (functions with static linkage 15929 whose address is never taken) 15930 + On i386, these local functions use register parameter passing 15931 conventions. 15932 + Reordering of functions in topological order of the call graph 15933 to enable better propagation of optimizing hints (such as the 15934 stack alignments needed by functions) in the back end. 15935 + Call graph based out-of-order inlining heuristics which allows 15936 to limit overall compilation unit growth (--param 15937 inline-unit-growth). 15938 Overall, the unit-at-a-time scheme produces a 1.3% improvement for 15939 the SPECint2000 benchmark on the i386 architecture (AMD Athlon 15940 CPU). 15941 * More realistic code size estimates used by inlining for C, 15942 Objective-C, C++ and Java. The growth of large functions can now be 15943 limited via --param large-function-insns and --param 15944 large-function-growth. 15945 * A new cfg-level loop optimizer pass replaces the old loop unrolling 15946 pass and adds two other loop transformations -- loop peeling and 15947 loop unswitching -- and also uses the profile feedback to limit 15948 code growth. (The three optimizations are enabled by 15949 -funroll-loops, -fpeel-loops and -funswitch-loops flags, 15950 respectively). 15951 The old loop unroller still can be enabled by -fold-unroll-loops 15952 and may produce better code in some cases, especially when the 15953 webizer optimization pass is not run. 15954 * A new web construction pass enabled via -fweb (and implied by -O3) 15955 improves the quality of register allocation, CSE, first scheduling 15956 pass and some other optimization passes by avoiding re-use of 15957 pseudo registers with non-overlapping live ranges. The pass almost 15958 always improves code quality but does make debugging difficult and 15959 thus is not enabled by default by -O2 15960 The pass is especially effective as cleanup after code duplication 15961 passes, such as the loop unroller or the tracer. 15962 * Experimental implementations of superblock or trace scheduling in 15963 the second scheduling pass can be enabled via 15964 -fsched2-use-superblocks and -fsched2-use-traces, respectively. 15965 15966 New Languages and Language specific improvements 15967 15968 Ada 15969 15970 * The Ada front end has been updated to include numerous bug fixes 15971 and enhancements. These include: 15972 + Improved project file support 15973 + Additional set of warnings about potential wrong code 15974 + Improved error messages 15975 + Improved code generation 15976 + Improved cross reference information 15977 + Improved inlining 15978 + Better run-time check elimination 15979 + Better error recovery 15980 + More efficient implementation of unbounded strings 15981 + Added features in GNAT.Sockets, GNAT.OS_Lib, GNAT.Debug_Pools, 15982 ... 15983 + New GNAT.xxxx packages (e.g. GNAT.Strings, 15984 GNAT.Exception_Action) 15985 + New pragmas 15986 + New -gnatS switch replacing gnatpsta 15987 + Implementation of new Ada features (in particular limited 15988 with, limited aggregates) 15989 15990 C/Objective-C/C++ 15991 15992 * Precompiled headers are now supported. Precompiled headers can 15993 dramatically speed up compilation of some projects. There are some 15994 known defects in the current precompiled header implementation that 15995 will result in compiler crashes in relatively rare situations. 15996 Therefore, precompiled headers should be considered a "technology 15997 preview" in this release. Read the manual for details about how to 15998 use precompiled headers. 15999 * File handling in the preprocessor has been rewritten. GCC no longer 16000 gets confused by symlinks and hardlinks, and now has a correct 16001 implementation of #import and #pragma once. These two directives 16002 have therefore been un-deprecated. 16003 * The undocumented extension that allowed C programs to have a label 16004 at the end of a compound statement, which has been deprecated since 16005 GCC 3.0, has been removed. 16006 * The cast-as-lvalue extension has been removed for C++ and 16007 deprecated for C and Objective-C. In particular, code like this: 16008 int i; 16009 (char) i = 5; 16010 16011 or this: 16012 char *p; 16013 ((int *) p)++; 16014 16015 is no longer accepted for C++ and will not be accepted for C and 16016 Objective-C in a future version. 16017 * The conditional-expression-as-lvalue extension has been deprecated 16018 for C and Objective-C. In particular, code like this: 16019 int a, b, c; 16020 (a ? b : c) = 2; 16021 16022 will not be accepted for C and Objective-C in a future version. 16023 * The compound-expression-as-lvalue extension has been deprecated for 16024 C and Objective-C. In particular, code like this: 16025 int a, b; 16026 (a, b) = 2; 16027 16028 will not be accepted for C and Objective-C in a future version. A 16029 possible non-intrusive workaround is the following: 16030 (*(a, &b)) = 2; 16031 16032 * Several [10]built-in functions such as __builtin_popcount for 16033 counting bits, finding the highest and lowest bit in a word, and 16034 parity have been added. 16035 * The -fwritable-strings option has been deprecated and will be 16036 removed. 16037 * Many C math library functions are now recognized as built-ins and 16038 optimized. 16039 * The C, C++, and Objective-C compilers can now handle source files 16040 written in any character encoding supported by the host C library. 16041 The default input character set is taken from the current locale, 16042 and may be overridden with the -finput-charset command line option. 16043 In the future we will add support for inline encoding markers. 16044 16045 C++ 16046 16047 * G++ is now much closer to full conformance to the ISO/ANSI C++ 16048 standard. This means, among other things, that a lot of invalid 16049 constructs which used to be accepted in previous versions will now 16050 be rejected. It is very likely that existing C++ code will need to 16051 be fixed. This document lists some of the most common issues. 16052 * A hand-written recursive-descent C++ parser has replaced the 16053 YACC-derived C++ parser from previous GCC releases. The new parser 16054 contains much improved infrastructure needed for better parsing of 16055 C++ source codes, handling of extensions, and clean separation 16056 (where possible) between proper semantics analysis and parsing. The 16057 new parser fixes many bugs that were found in the old parser. 16058 * You must now use the typename and template keywords to disambiguate 16059 dependent names, as required by the C++ standard. 16060 struct K { 16061 typedef int mytype_t; 16062 }; 16063 16064 template <class T1> struct A { 16065 template <class T2> struct B { 16066 void callme(void); 16067 }; 16068 16069 template <int N> void bar(void) 16070 { 16071 // Use 'typename' to tell the parser that T1::mytype_t names 16072 // a type. This is needed because the name is dependent (in 16073 // this case, on template parameter T1). 16074 typename T1::mytype_t x; 16075 x = 0; 16076 } 16077 }; 16078 16079 template <class T> void template_func(void) 16080 { 16081 // Use 'template' to prefix member templates within 16082 // dependent types (a has type A<T>, which depends on 16083 // the template parameter T). 16084 A<T> a; 16085 a.template bar<0>(); 16086 16087 // Use 'template' to tell the parser that B is a nested 16088 // template class (dependent on template parameter T), and 16089 // 'typename' because the whole A<T>::B<int> is 16090 // the name of a type (again, dependent). 16091 typename A<T>::template B<int> b; 16092 b.callme(); 16093 } 16094 16095 void non_template_func(void) 16096 { 16097 // Outside of any template class or function, no names can be 16098 // dependent, so the use of the keyword 'typename' and 'template' 16099 // is not needed (and actually forbidden). 16100 A<K> a; 16101 a.bar<0>(); 16102 A<K>::B<float> b; 16103 b.callme(); 16104 } 16105 * In a template definition, unqualified names will no longer find 16106 members of a dependent base (as specified by [temp.dep]/3 in the 16107 C++ standard). For example, 16108 template <typename T> struct B { 16109 int m; 16110 int n; 16111 int f (); 16112 int g (); 16113 }; 16114 int n; 16115 int g (); 16116 template <typename T> struct C : B<T> { 16117 void h () 16118 { 16119 m = 0; // error 16120 f (); // error 16121 n = 0; // ::n is modified 16122 g (); // ::g is called 16123 } 16124 }; 16125 You must make the names dependent, e.g. by prefixing them with 16126 this->. Here is the corrected definition of C<T>::h, 16127 template <typename T> void C<T>::h () 16128 { 16129 this->m = 0; 16130 this->f (); 16131 this->n = 0 16132 this->g (); 16133 } 16134 As an alternative solution (unfortunately not backwards compatible 16135 with GCC 3.3), you may use using declarations instead of this->: 16136 template <typename T> struct C : B<T> { 16137 using B<T>::m; 16138 using B<T>::f; 16139 using B<T>::n; 16140 using B<T>::g; 16141 void h () 16142 { 16143 m = 0; 16144 f (); 16145 n = 0; 16146 g (); 16147 } 16148 }; 16149 * In templates, all non-dependent names are now looked up and bound 16150 at definition time (while parsing the code), instead of later when 16151 the template is instantiated. For instance: 16152 void foo(int); 16153 16154 template <int> struct A { 16155 static void bar(void){ 16156 foo('a'); 16157 } 16158 }; 16159 16160 void foo(char); 16161 16162 int main() 16163 { 16164 A<0>::bar(); // Calls foo(int), used to call foo(char). 16165 } 16166 16167 * In an explicit instantiation of a class template, you must use 16168 class or struct before the template-id: 16169 template <int N> 16170 class A {}; 16171 16172 template A<0>; // error, not accepted anymore 16173 template class A<0>; // OK 16174 * The "named return value" and "implicit typename" extensions have 16175 been removed. 16176 * Default arguments in function types have been deprecated and will 16177 be removed. 16178 * ARM-style name-injection of friend declarations has been deprecated 16179 and will be removed. For example: struct S { friend void f(); }; 16180 void g() { f(); } will not be accepted by future versions of G++; 16181 instead a declaration of "f" will need to be present outside of the 16182 scope of "S". 16183 * Covariant returns are implemented for all but varadic functions 16184 that require an adjustment. 16185 * When -pedantic is used, G++ now issues errors about spurious 16186 semicolons. For example, 16187 namespace N {}; // Invalid semicolon. 16188 void f() {}; // Invalid semicolon. 16189 * G++ no longer accepts attributes for a declarator after the 16190 initializer associated with that declarator. For example, 16191 X x(1) __attribute__((...)); 16192 is no longer accepted. Instead, use: 16193 X x __attribute__((...)) (1); 16194 * Inside the scope of a template class, the name of the class itself 16195 can be treated as either a class or a template. So GCC used to 16196 accept the class name as argument of type template, and template 16197 template parameter. However this is not C++ standard compliant. Now 16198 the name is not treated as a valid template template argument 16199 unless you qualify the name by its scope. For example, the code 16200 below no longer compiles. 16201 template <template <class> class TT> class X {}; 16202 template <class T> class Y { 16203 X<Y> x; // Invalid, Y is always a type template parameter. 16204 }; 16205 The valid code for the above example is 16206 X< ::Y> x; // Valid. 16207 (Notice the space between < and : to prevent GCC to interpret this 16208 as a digraph for [.) 16209 * Friend declarations that refer to template specializations are 16210 rejected if the template has not already been declared. For 16211 example, 16212 template <typename T> 16213 class C { 16214 friend void f<> (C&); 16215 }; 16216 is rejected. You must first declare f as a template, 16217 template <typename T> 16218 void f(T); 16219 * In case of friend declarations, every name used in the friend 16220 declaration must be accessible at the point of that declaration. 16221 Previous versions of G++ used to be less strict about this and 16222 allowed friend declarations for private class members, for example. 16223 See the ISO C++ Standard Committee's [11]defect report #209 for 16224 details. 16225 * Declaration of member functions of class templates as friends are 16226 supported. For example, 16227 template <typename T> struct A { 16228 void f(); 16229 }; 16230 class C { 16231 template <typename T> friend void A<T>::f(); 16232 }; 16233 * You must use template <> to introduce template specializations, as 16234 required by the standard. For example, 16235 template <typename T> 16236 struct S; 16237 16238 struct S<int> { }; 16239 is rejected. You must write, 16240 template <> struct S<int> {}; 16241 * G++ used to accept code like this, 16242 struct S { 16243 int h(); 16244 void f(int i = g()); 16245 int g(int i = h()); 16246 }; 16247 This behavior is not mandated by the standard. Now G++ issues an 16248 error about this code. To avoid the error, you must move the 16249 declaration of g before the declaration of f. The default arguments 16250 for g must be visible at the point where it is called. 16251 * The C++ ABI Section 3.3.3 specifications for the array construction 16252 routines __cxa_vec_new2 and __cxa_vec_new3 were changed to return 16253 NULL when the allocator argument returns NULL. These changes are 16254 incorporated into the libstdc++ runtime library. 16255 * Using a name introduced by a typedef in a friend declaration or in 16256 an explicit instantiation is now rejected, as specified by the ISO 16257 C++ standard. 16258 class A; 16259 typedef A B; 16260 class C { 16261 friend class B; // error, no typedef name here 16262 friend B; // error, friend always needs class/struct/enum 16263 friend class A; // OK 16264 }; 16265 16266 template <int> class Q {}; 16267 typedef Q<0> R; 16268 template class R; // error, no typedef name here 16269 template class Q<0>; // OK 16270 * When allocating an array with a new expression, GCC used to allow 16271 parentheses around the type name. This is actually ill-formed and 16272 it is now rejected: 16273 int* a = new (int)[10]; // error, not accepted anymore 16274 int* a = new int[10]; // OK 16275 * When binding an rvalue of class type to a reference, the copy 16276 constructor of the class must be accessible. For instance, consider 16277 the following code: 16278 class A 16279 { 16280 public: 16281 A(); 16282 16283 private: 16284 A(const A&); // private copy ctor 16285 }; 16286 16287 A makeA(void); 16288 void foo(const A&); 16289 16290 void bar(void) 16291 { 16292 foo(A()); // error, copy ctor is not accessible 16293 foo(makeA()); // error, copy ctor is not accessible 16294 16295 A a1; 16296 foo(a1); // OK, a1 is a lvalue 16297 } 16298 This might be surprising at first sight, especially since most 16299 popular compilers do not correctly implement this rule ([12]further 16300 details). 16301 * When forming a pointer to member or a pointer to member function, 16302 access checks for class visibility (public, protected, private) are 16303 now performed using the qualifying scope of the name itself. This 16304 is better explained with an example: 16305 class A 16306 { 16307 public: 16308 void pub_func(); 16309 protected: 16310 void prot_func(); 16311 private: 16312 void priv_func(); 16313 }; 16314 16315 class B : public A 16316 { 16317 public: 16318 void foo() 16319 { 16320 &A::pub_func; // OK, pub_func is accessible through A 16321 &A::prot_func; // error, cannot access prot_func through A 16322 &A::priv_func; // error, cannot access priv_func through A 16323 16324 &B::pub_func; // OK, pub_func is accessible through B 16325 &B::prot_func; // OK, can access prot_func through B (within B) 16326 &B::priv_func; // error, cannot access priv_func through B 16327 } 16328 }; 16329 16330 Runtime Library (libstdc++) 16331 16332 * Optimization work: 16333 + Streamlined streambuf, filebuf, separate synched with C 16334 Standard I/O streambuf. 16335 + All formatted I/O now uses cached locale information. 16336 + STL optimizations (memory/speed for list, red-black trees as 16337 used by sets and maps). 16338 + More use of GCC builtins. 16339 + String optimizations (avoid contention on 16340 increment/decrement-and-test of the reference count in the 16341 empty-string object, constructor from input_iterators 16342 speedup). 16343 * Static linkage size reductions. 16344 * Large File Support (files larger than 2 GB on 32-bit systems). 16345 * Wide character and variable encoding filebuf work (UTF-8, Unicode). 16346 * Generic character traits. 16347 * Also support wchar_t specializations on Mac OS 10.3.x, FreeBSD 5.x, 16348 Solaris 2.7 and above, AIX 5.x, Irix 6.5. 16349 * The allocator class is now standard-conformant, and two additional 16350 extension allocators have been added, mt_alloc and 16351 bitmap_allocator. 16352 * PCH support: -include bits/stdc++.h (2x compile speedup). 16353 * Rewrote __cxa_demangle with support for C++ style allocators. 16354 * New debug modes for STL containers and iterators. 16355 * Testsuite rewrite: five times as many tests, plus increasingly 16356 sophisticated tests, including I/O, MT, multi-locale, wide and 16357 narrow characters. 16358 * Use current versions of GNU "autotools" for build/configuration. 16359 16360 Objective-C 16361 16362 * The Objective-C front end has been updated to include the numerous 16363 bug fixes and enhancements previously available only in Apple's 16364 version of GCC. These include: 16365 + Structured exception (@try... @catch... @finally, @throw) and 16366 synchronization (@synchronized) support. These are accessible 16367 via the -fobjc-exceptions switch; as of this writing, they may 16368 only be used in conjunction with -fnext-runtime on Mac OS X 16369 10.3 and later. See [13]Options Controlling Objective-C 16370 Dialect for more information. 16371 + An overhaul of @encode logic. The C99 _Bool and C++ bool type 16372 may now be encoded as 'B'. In addition, the back-end/codegen 16373 dependencies have been removed. 16374 + An overhaul of message dispatch construction, ensuring that 16375 the various receiver types (and casts thereof) are handled 16376 properly, and that correct diagnostics are issued. 16377 + Support for "Zero-Link" (-fzero-link) and "Fix-and-Continue" 16378 (-freplace-objc-classes) debugging modes, currently available 16379 on Mac OS X 10.3 and later. See [14]Options Controlling 16380 Objective-C Dialect for more information. 16381 + Access to optimized runtime entry points (-fno-nil-receivers ) 16382 on the assumption that message receivers are never nil. This 16383 is currently available on Mac OS X 10.3 and later. See 16384 [15]Options Controlling Objective-C Dialect for more 16385 information. 16386 16387 Java 16388 16389 * Compiling a .jar file will now cause non-.class entries to be 16390 automatically compiled as resources. 16391 * libgcj has been ported to Darwin. 16392 * Jeff Sturm has adapted Jan Hubicka's call graph optimization code 16393 to gcj. 16394 * libgcj has a new gcjlib URL type; this lets URLClassLoader load 16395 code from shared libraries. 16396 * libgcj has been much more completely merged with [16]GNU Classpath. 16397 * Class loading is now much more correct; in particular the caller's 16398 class loader is now used when that is required. 16399 * [17]Eclipse 2.x will run out of the box using gij. 16400 * Parts of java.nio have been implemented. Direct and indirect 16401 buffers work, as do fundamental file and socket operations. 16402 * java.awt has been improved, though it is still not ready for 16403 general use. 16404 * The HTTP protocol handler now uses HTTP/1.1 and can handle the POST 16405 method. 16406 * The MinGW port has matured. Enhancements include socket timeout 16407 support, thread interruption, improved Runtime.exec() handling and 16408 support for accented characters in filenames. 16409 16410 Fortran 16411 16412 * Fortran improvements are listed in the [18]Fortran documentation. 16413 16414 New Targets and Target Specific Improvements 16415 16416 Alpha 16417 16418 * Several [19]built-in functions have been added such as 16419 __builtin_alpha_zap to allow utilizing the more obscure 16420 instructions of the CPU. 16421 * Parameter passing of complex arguments has changed to match the 16422 ABI. This change is incompatible with previous GCC versions, but 16423 does fix compatibility with the Tru64 compiler and several corner 16424 cases where GCC was incompatible with itself. 16425 16426 ARM 16427 16428 * Nicolas Pitre has contributed his hand-coded floating-point support 16429 code for ARM. It is both significantly smaller and faster than the 16430 existing C-based implementation, even when building applications 16431 for Thumb. The arm-elf configuration has been converted to use the 16432 new code. 16433 * Support for the Intel's iWMMXt architecture, a second generation 16434 XScale processor, has been added. Enabled at run time with the 16435 -mcpu=iwmmxt command line switch. 16436 * A new ARM target has been added: arm-wince-pe. This is similar to 16437 the arm-pe target, but it defaults to using the APCS32 ABI. 16438 * The existing ARM pipeline description has been converted to the use 16439 the [20]DFA processor pipeline model. There is not much change in 16440 code performance, but the description is now [21]easier to 16441 understand. 16442 * Support for the Cirrus EP9312 Maverick floating point co-processor 16443 added. Enabled at run time with the -mcpu=ep9312 command line 16444 switch. Note however that the multilibs to support this chip are 16445 currently disabled in gcc/config/arm/t-arm-elf, so if you want to 16446 enable their production you will have to uncomment the entries in 16447 that file. 16448 16449 H8/300 16450 16451 * Support for long long has been added. 16452 * Support for saveall attribute has been added. 16453 * Pavel Pisa contributed hand-written 32-bit-by-32-bit division code 16454 for H8/300H and H8S, which is much faster than the previous 16455 implementation. 16456 * A lot of small performance improvements. 16457 16458 IA-32/AMD64 (x86-64) 16459 16460 * Tuning for K8 (AMD Opteron/Athlon64) core is available via 16461 -march=k8 and -mcpu=k8. 16462 * Scalar SSE code generation carefully avoids reformatting penalties, 16463 hidden dependencies and minimizes the number of uops generated on 16464 both Intel and AMD CPUs. 16465 * Vector MMX and SSE operands are now passed in registers to improve 16466 performance and match the argument passing convention used by the 16467 Intel C++ Compiler. As a result it is not possible to call 16468 functions accepting vector arguments compiled by older GCC version. 16469 * Conditional jump elimination is now more aggressive on modern CPUs. 16470 * The Athlon ports has been converted to use the DFA processor 16471 pipeline description. 16472 * Optimization of indirect tail calls is now possible in a similar 16473 fashion as direct sibcall optimization. 16474 * Further small performance improvements. 16475 * -m128bit-long-double is now less buggy. 16476 * __float128 support in 64-bit compilation. 16477 * Support for data structures exceeding 2GB in 64-bit mode. 16478 * -mcpu has been renamed to -mtune. 16479 16480 IA-64 16481 16482 * Tuning code for the Itanium 2 processor has been added. The 16483 generation of code tuned for Itanium 2 (option -mtune=itanium2) is 16484 enabled by default now. To generate code tuned for Itanium 1 the 16485 option -mtune=itanium1 should be used. 16486 * [22]DFA processor pipeline descriptions for the IA-64 processors 16487 have been added. This resulted in about 3% improvement on the 16488 SPECInt2000 benchmark for Itanium 2. 16489 * Instruction bundling for the IA-64 processors has been rewritten 16490 using the DFA pipeline hazard recognizer. It resulted in about 60% 16491 compiler speedup on the SPECInt2000 C programs. 16492 16493 M32R 16494 16495 * Support for the M32R/2 processor has been added by Renesas. 16496 * Support for an M32R GNU/Linux target and PIC code generation has 16497 been added by Renesas. 16498 16499 M68000 16500 16501 * Bernardo Innocenti (Develer S.r.l.) has contributed the 16502 m68k-uclinux target, based on former work done by Paul Dale 16503 (SnapGear Inc.). Code generation for the ColdFire processors family 16504 has been enhanced and extended to support the MCF 53xx and MCF 54xx 16505 cores, integrating former work done by Peter Barada (Motorola). 16506 16507 MIPS 16508 16509 Processor-specific changes 16510 16511 * Support for the RM7000 and RM9000 processors has been added. It can 16512 be selected using the -march compiler option and should work with 16513 any MIPS I (mips-*) or MIPS III (mips64-*) configuration. 16514 * Support for revision 2 of the MIPS32 ISA has been added. It can be 16515 selected with the command-line option -march=mips32r2. 16516 * There is a new option, -mfix-sb1, to work around certain SB-1 16517 errata. 16518 16519 Configuration 16520 16521 * It is possible to customize GCC using the following configure-time 16522 options: 16523 + --with-arch, which specifies the default value of the -march 16524 option. 16525 + --with-tune, which specifies the default value of the -mtune 16526 option. 16527 + --with-abi, which specifies the default ABI. 16528 + --with-float=soft, which tells GCC to use software floating 16529 point by default. 16530 + --with-float=hard, which tells GCC to use hardware floating 16531 point by default. 16532 * A 64-bit GNU/Linux port has been added. The associated 16533 configurations are mips64-linux-gnu and mips64el-linux-gnu. 16534 * The 32-bit GNU/Linux port now supports Java. 16535 * The IRIX 6 configuration now supports the o32 ABI and will build 16536 o32 multilibs by default. This support is compatible with both 16537 binutils and the SGI tools, but note that several features, 16538 including debugging information and DWARF2 exception handling, are 16539 only available when using the GNU assembler. Use of the GNU 16540 assembler and linker (version 2.15 or above) is strongly 16541 recommended. 16542 * The IRIX 6 configuration now supports 128-bit long doubles. 16543 * There are two new RTEMS-specific configurations, mips-rtems and 16544 mipsel-rtems. 16545 * There are two new *-elf configurations, mipsisa32r2-elf and 16546 mipsisa32r2el-elf. 16547 16548 General 16549 16550 * Several [23]ABI bugs have been fixed. Unfortunately, these changes 16551 will break binary compatibility with earlier releases. 16552 * GCC can now use explicit relocation operators when generating 16553 -mabicalls code. This behavior is controlled by -mexplicit-relocs 16554 and can have several performance benefits. For example: 16555 + It allows for more optimization of GOT accesses, including 16556 better scheduling and redundancy elimination. 16557 + It allows sibling calls to be implemented as jumps. 16558 + n32 and n64 leaf functions can use a call-clobbered global 16559 pointer instead of $28. 16560 + The code to set up $gp can be removed from functions that 16561 don't need it. 16562 * A new option, -mxgot, allows the GOT to be bigger than 64k. This 16563 option is equivalent to the assembler's -xgot option and should be 16564 used instead of -Wa,-xgot. 16565 * Frame pointer elimination is now supported when generating 64-bit 16566 MIPS16 code. 16567 * Inline block moves have been optimized to take more account of 16568 alignment information. 16569 * Many internal changes have been made to the MIPS port, mostly aimed 16570 at reducing the reliance on assembler macros. 16571 16572 PowerPC 16573 16574 * GCC 3.4 releases have a number of fixes for PowerPC and PowerPC64 16575 [24]ABI incompatibilities regarding the way parameters are passed 16576 during functions calls. These changes may result in incompatibility 16577 between code compiled with GCC 3.3 and GCC 3.4. 16578 16579 PowerPC Darwin 16580 16581 * Support for shared/dylib gcc libraries has been added. It is 16582 enabled by default on powerpc-apple-darwin7.0.0 and up. 16583 * Libgcj is enabled by default. On systems older than 16584 powerpc-apple-darwin7.0.0 you need to install dlcompat. 16585 * 128-bit IBM extended precision format support added for long 16586 double. 16587 16588 PowerPC64 GNU/Linux 16589 16590 * By default, PowerPC64 GNU/Linux now uses natural alignment of 16591 structure elements. The old four byte alignment for double, with 16592 special rules for a struct starting with a double, can be chosen 16593 with -malign-power. This change may result in incompatibility 16594 between code compiled with GCC 3.3 and GCC 3.4. 16595 * -mabi=altivec is now the default rather than -mabi=no-altivec. 16596 * 128-bit IBM extended precision format support added for long 16597 double. 16598 16599 S/390 and zSeries 16600 16601 * New command-line options allow to specify the intended execution 16602 environment for generated code: 16603 + -mesa/-mzarch allows to specify whether to generate code 16604 running in ESA/390 mode or in z/Architecture mode (this is 16605 applicable to 31-bit code only). 16606 + -march allows to specify a minimum processor architecture 16607 level (g5, g6, z900, or z990). 16608 + -mtune allows to specify which processor to tune for. 16609 * It is possible to customize GCC using the following configure-time 16610 options: 16611 + --with-mode, which specifies whether to default to assuming 16612 ESA/390 or z/Architecture mode. 16613 + --with-arch, which specifies the default value of the -march 16614 option. 16615 + --with-tune, which specifies the default value of the -mtune 16616 option. 16617 * Support for the z990 processor has been added, and can be selected 16618 using -march=z990 or -mtune=z990. This includes instruction 16619 scheduling tuned for the superscalar instruction pipeline of the 16620 z990 processor as well as support for all new instructions provided 16621 by the long-displacement facility. 16622 * Support to generate 31-bit code optimized for zSeries processors 16623 (running in ESA/390 or in z/Architecture mode) has been added. This 16624 can be selected using -march=z900 and -mzarch respectively. 16625 * Instruction scheduling for the z900 and z990 processors now uses 16626 the DFA pipeline hazard recognizer. 16627 * GCC no longer generates code to maintain a stack backchain, 16628 previously used to generate stack backtraces for debugging 16629 purposes. As replacement that does not incur runtime overhead, 16630 DWARF-2 call frame information is provided by GCC; this is 16631 supported by GDB 6.1. The old behavior can be restored using the 16632 -mbackchain option. 16633 * The stack frame size of functions may now exceed 2 GB in 64-bit 16634 code. 16635 * A port for the 64-bit IBM TPF operating system has been added; the 16636 configuration is s390x-ibm-tpf. This configuration is supported as 16637 cross-compilation target only. 16638 * Various changes to improve the generated code have been 16639 implemented, including: 16640 + GCC now uses the MULTIPLY AND ADD and MULTIPLY AND SUBTRACT 16641 instructions to significantly speed up many floating-point 16642 applications. 16643 + GCC now uses the ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL 16644 WITH BORROW instructions to speed up long long arithmetic. 16645 + GCC now uses the SEARCH STRING instruction to implement 16646 strlen(). 16647 + In many cases, function call overhead for 31-bit code has been 16648 reduced by placing the literal pool after the function code 16649 instead of after the function prolog. 16650 + Register 14 is no longer reserved in 64-bit code. 16651 + Handling of global register variables has been improved. 16652 16653 SPARC 16654 16655 * The option -mflat is deprecated. 16656 * Support for large (> 2GB) frames has been added to the 64-bit port. 16657 * Several [25]ABI bugs have been fixed. Unfortunately, these changes 16658 will break binary compatibility with earlier releases. 16659 * The default debugging format has been switched from STABS to 16660 DWARF-2 for 32-bit code on Solaris 7 and later. DWARF-2 is already 16661 the default debugging format for 64-bit code on Solaris. 16662 16663 SuperH 16664 16665 * Support for the SH2E processor has been added. Enabled at run time 16666 with the -m2e command line switch, or at configure time by 16667 specifying sh2e as the machine part of the target triple. 16668 16669 V850 16670 16671 * Support for the Mitsubishi V850E1 processor has been added. This is 16672 a variant of the V850E processor with some additional debugging 16673 instructions. 16674 16675 Xtensa 16676 16677 * Several ABI bugs have been fixed. Unfortunately, these changes 16678 break binary compatibility with earlier releases. 16679 + For big-endian processors, the padding of aggregate return 16680 values larger than a word has changed. If the size of an 16681 aggregate return value is not a multiple of 32 bits, previous 16682 versions of GCC inserted padding in the most-significant bytes 16683 of the first return value register. Aggregates larger than a 16684 word are now padded in the least-significant bytes of the last 16685 return value register used. Aggregates smaller than a word are 16686 still padded in the most-significant bytes. The return value 16687 padding has not changed for little-endian processors. 16688 + Function arguments with 16-byte alignment are now properly 16689 aligned. 16690 + The implementation of the va_list type has changed. A va_list 16691 value created by va_start from a previous release cannot be 16692 used with va_arg from this release, or vice versa. 16693 * More processor configuration options for Xtensa processors are 16694 supported: 16695 + the ABS instruction is now optional; 16696 + the ADDX* and SUBX* instructions are now optional; 16697 + an experimental CONST16 instruction can be used to synthesize 16698 constants instead of loading them from constant pools. 16699 These and other Xtensa processor configuration options can no 16700 longer be enabled or disabled by command-line options; the 16701 processor configuration must be specified by the xtensa-config.h 16702 header file when building GCC. Additionally, the 16703 -mno-serialize-volatile option is no longer supported. 16704 16705 Obsolete Systems 16706 16707 Support for a number of older systems has been declared obsolete in GCC 16708 3.4. Unless there is activity to revive them, the next release of GCC 16709 will have their sources permanently removed. 16710 16711 All configurations of the following processor architectures have been 16712 declared obsolete: 16713 * Mitsubishi D30V, d30v-* 16714 * AT&T DSP1600 and DSP1610, dsp16xx-* 16715 * Intel 80960, i960 16716 16717 Also, some individual systems have been obsoleted: 16718 * ARM Family 16719 + Support for generating code for operation in APCS/26 mode 16720 (-mapcs-26). 16721 * IBM ESA/390 16722 + "Bigfoot" port, i370-*. (The other port, s390-*, is actively 16723 maintained and supported.) 16724 * Intel 386 family 16725 + MOSS, i?86-moss-msdos and i?86-*-moss* 16726 + NCR 3000 running System V r.4, i?86-ncr-sysv4* 16727 + FreeBSD with a.out object format, i?86-*-freebsd*aout* and 16728 i?86-*-freebsd2* 16729 + GNU/Linux with a.out object format, i?86-linux*aout* 16730 + GNU/Linux with libc5, a.k.a. glibc1, i?86-linux*libc1* 16731 + Interix versions before Interix 3, i?86-*-interix 16732 + Mach microkernel, i?86-mach* 16733 + SCO UnixWare with UDK, i?86-*-udk* 16734 + Generic System V releases 1, 2, and 3, i?86-*-sysv[123]* 16735 + VSTa microkernel, i386-*-vsta 16736 * Motorola M68000 family 16737 + HPUX, m68k-hp-hpux* and m68000-hp-hpux* 16738 + NetBSD with a.out object format (before NetBSD 1.4), 16739 m68k-*-*-netbsd* except m68k-*-*-netbsdelf* 16740 + Generic System V r.4, m68k-*-sysv4* 16741 * VAX 16742 + Generic VAX, vax-*-* (This is generic VAX only; we have not 16743 obsoleted any VAX triples for specific operating systems.) 16744 16745 Documentation improvements 16746 16747 Other significant improvements 16748 16749 * The build system has undergone several significant cleanups. 16750 Subdirectories will only be configured if they are being built, and 16751 all subdirectory configures are run from the make command. The top 16752 level has been autoconfiscated. 16753 * Building GCC no longer writes to its source directory. This should 16754 help those wishing to share a read-only source directory over NFS 16755 or build from a CD. The exceptions to this feature are if you 16756 configure with either --enable-maintainer-mode or 16757 --enable-generated-files-in-srcdir. 16758 * The -W warning option has been renamed to -Wextra, which is more 16759 easily understood. The older spelling will be retained for 16760 backwards compatibility. 16761 * Substantial improvements in compile time have been made, 16762 particularly for non-optimizing compilations. 16763 __________________________________________________________________ 16764 16765 GCC 3.4.0 16766 16767 Bug Fixes 16768 16769 A vast number of bugs have been fixed in 3.4.0, too many to publish a 16770 complete list here. [26]Follow this link to query the Bugzilla database 16771 for the list of over 900 bugs fixed in 3.4.0. This is the list of all 16772 bugs marked as resolved and fixed in 3.4.0 that are not flagged as 3.4 16773 regressions. 16774 __________________________________________________________________ 16775 16776 GCC 3.4.1 16777 16778 Bug Fixes 16779 16780 This section lists the problem reports (PRs) from GCC's bug tracking 16781 system that are known to be fixed in the 3.4.1 release. This list might 16782 not be complete (that is, it is possible that some PRs that have been 16783 fixed are not listed here). 16784 16785 Bootstrap failures 16786 16787 * [27]10129 Ada bootstrap fails on PPC-Darwin - invalid assembler 16788 emitted - PIC related 16789 * [28]14576 [ARM] ICE in libiberty when building gcc-3.4 for arm-elf 16790 * [29]14760 A bug in configure.in prevents using both 16791 --program-suffix and --program-prefix 16792 * [30]14671 [hppa64] bootstrap fails: ICE in 16793 save_call_clobbered_regs, in caller_save.c 16794 * [31]15093 [alpha][Java] make bootstrap fails to configure libffi on 16795 Alpha 16796 * [32]15178 Solaris 9/x86 fails linking after stage 3 16797 16798 Multi-platform internal compiler errors (ICEs) 16799 16800 * [33]12753 (preprocessor) Memory corruption in preprocessor on bad 16801 input 16802 * [34]13985 ICE in gcc.c-torture/compile/930621-1.c 16803 * [35]14810 (c++) tree check failures with invalid code involving 16804 templates 16805 * [36]14883 (c++) ICE on invalid code, in cp_parser_lookup_name, in 16806 cp/parser.c 16807 * [37]15044 (c++) ICE on syntax error, template header 16808 * [38]15057 (c++) Compiling of conditional value throw constructs 16809 cause a segmentation violation 16810 * [39]15064 (c++) typeid of template parameter gives ICE 16811 * [40]15142 (c++) ICE when passing a string where a char* is expected 16812 in a throw statement 16813 * [41]15159 ICE in rtl_verify_flow_info_1 16814 * [42]15165 (c++) ICE in instantiate_template 16815 * [43]15193 Unary minus using pointer to V4SF vector causes 16816 -fforce-mem to exhaust all memory 16817 * [44]15209 (c++) Runs out of memory with packed structs 16818 * [45]15227 (c++) Trouble with invalid function definition 16819 * [46]15285 (c++) instantiate_type ICE when forming pointer to 16820 template function 16821 * [47]15299 (c++) ICE in resolve_overloaded_unification 16822 * [48]15329 (c++) ICE on constructor of member template 16823 * [49]15550 ICE in extract_insn, in recog.c 16824 * [50]15554 (c++) ICE in tsubst_copy, in cp/pt.c 16825 * [51]15640 (c++) ICE on invalid code in arg_assoc, in 16826 cp/name-lookup.c 16827 * [52]15666 [unit-at-a-time] Gcc abort on valid code 16828 * [53]15696 (c++) ICE with bad pointer-to-member code 16829 * [54]15701 (c++) ICE with friends and template template parameter 16830 * [55]15761 ICE in do_SUBST, in combine.c 16831 * [56]15829 (c++) ICE on Botan-1.3.13 due to -funroll-loops 16832 16833 Ada 16834 16835 * [57]14538 All RTEMS targets broken for gnat 16836 16837 C front end 16838 16839 * [58]12391 missing warning about assigning to an incomplete type 16840 * [59]14649 atan(1.0) should not be a constant expression 16841 * [60]15004 [unit-at-a-time] no warning for unused paramater in 16842 static function 16843 * [61]15749 --pedantic-errors behaves differently from --pedantic 16844 with C-compiler on GNU/Linux 16845 16846 C++ compiler and library 16847 16848 * [62]10646 non-const reference is incorrectly matched in a "const T" 16849 partial specialization 16850 * [63]12077 wcin.rdbuf()->in_avail() return value too high 16851 * [64]13598 enc_filebuf doesn't work 16852 * [65]14211 const_cast returns lvalue but should be rvalue 16853 * [66]14220 num_put::do_put() undesired float/double behavior 16854 * [67]14245 problem with user-defined allocators in std::basic_string 16855 * [68]14340 libstdc++ Debug mode: failure to convert iterator to 16856 const_iterator 16857 * [69]14600 __gnu_cxx::stdio_sync_filebuf should expose internal 16858 FILE* 16859 * [70]14668 no warning anymore for reevaluation of declaration 16860 * [71]14775 LFS (large file support) tests missing 16861 * [72]14821 Duplicate namespace alias declaration should not conflict 16862 * [73]14930 Friend declaration ignored 16863 * [74]14932 cannot use offsetof to get offsets of array elements in 16864 g++ 3.4.0 16865 * [75]14950 [non unit-at-a-time] always_inline does not mix with 16866 templates and -O0 16867 * [76]14962 g++ ignores #pragma redefine_extname 16868 * [77]14975 Segfault on low-level write error during imbue 16869 * [78]15002 Linewise stream input is unusably slow (std::string slow) 16870 * [79]15025 compiler accepts redeclaration of template as 16871 non-template 16872 * [80]15046 [arm] Math functions misdetected by cross configuration 16873 * [81]15069 a bit test on a variable of enum type is miscompiled 16874 * [82]15074 g++ -lsupc++ still links against libstdc++ 16875 * [83]15083 spurious "statement has no effect" warning 16876 * [84]15096 parse error with templates and pointer to const member 16877 * [85]15287 combination of operator[] and operator .* fails in 16878 templates 16879 * [86]15317 __attribute__ unused in first parameter of constructor 16880 gives error 16881 * [87]15337 sizeof on incomplete type diagnostic 16882 * [88]15361 bitset<>::_Find_next fails 16883 * [89]15412 _GLIBCXX_ symbols symbols defined and used in different 16884 namespaces 16885 * [90]15427 valid code results in incomplete type error 16886 * [91]15471 Incorrect member pointer offsets in anonymous 16887 structs/unions 16888 * [92]15503 nested template problem 16889 * [93]15507 compiler hangs while laying out union 16890 * [94]15542 operator & and template definitions 16891 * [95]15565 SLES9: leading + sign for unsigned int with showpos 16892 * [96]15625 friend defined inside a template fails to find static 16893 function 16894 * [97]15629 Function templates, overloads, and friend name injection 16895 * [98]15742 'noreturn' attribute ignored in method of template 16896 functions. 16897 * [99]15775 Allocator::pointer consistently ignored 16898 * [100]15821 Duplicate namespace alias within namespace rejected 16899 * [101]15862 'enum yn' fails (confict with undeclared builtin) 16900 * [102]15875 rejects pointer to member in template 16901 * [103]15877 valid code using templates and anonymous enums is 16902 rejected 16903 * [104]15947 Puzzling error message for wrong destructor declaration 16904 in template class 16905 * [105]16020 cannot copy __gnu_debug::bitset 16906 * [106]16154 input iterator concept too restrictive 16907 * [107]16174 deducing top-level consts 16908 16909 Java 16910 16911 * [108]14315 Java compiler is not parallel make safe 16912 16913 Fortran 16914 16915 * [109]15151 [g77] incorrect logical i/o in 64-bit mode 16916 16917 Objective-C 16918 16919 * [110]7993 private variables cannot be shadowed in subclasses 16920 16921 Optimization bugs 16922 16923 * [111]15228 useless copies of floating point operands 16924 * [112]15345 [non-unit-at-a-time] unreferenced nested inline 16925 functions not optimized away 16926 * [113]15945 Incorrect floating point optimization 16927 * [114]15526 ftrapv aborts on 0 * (-1) 16928 * [115]14690 Miscompiled POOMA tests 16929 * [116]15112 GCC generates code to write to unchanging memory 16930 16931 Preprocessor 16932 16933 * [117]15067 Minor glitch in the source of cpp 16934 16935 Main driver program bugs 16936 16937 * [118]1963 collect2 interprets -oldstyle_liblookup as -o 16938 ldstyle_liblookup 16939 16940 x86-specific (Intel/AMD) 16941 16942 * [119]15717 Error: can't resolve `L0' {*ABS* section} - `xx' {*UND* 16943 section} 16944 16945 HPPA-specific 16946 16947 * [120]14782 GCC produces an unaligned data access at -O2 16948 * [121]14828 FAIL: gcc.c-torture/execute/20030408-1.c execution, -O2 16949 * [122]15202 ICE in reload_cse_simplify_operands, in postreload.c 16950 16951 IA64-specific 16952 16953 * [123]14610 __float80 constants incorrectly emitted 16954 * [124]14813 init_array sections are initialized in the wrong order 16955 * [125]14857 GCC segfault on duplicated asm statement 16956 * [126]15598 Gcc 3.4 ICE on valid code 16957 * [127]15653 Gcc 3.4 ICE on valid code 16958 16959 MIPS-specific 16960 16961 * [128]15189 wrong filling of delay slot with -march=mips1 -G0 16962 -mno-split-addresses -mno-explicit-relocs 16963 * [129]15331 Assembler error building gnatlib on IRIX 6.5 with GNU as 16964 2.14.91 16965 * [130]16144 Bogus reference to __divdf3 when -O1 16966 * [131]16176 Miscompilation of unaligned data in MIPS backend 16967 16968 PowerPC-specific 16969 16970 * [132]11591 ICE in gcc.dg/altivec-5.c 16971 * [133]12028 powerpc-eabispe produces bad sCOND operation 16972 * [134]14478 rs6000 geu/ltu patterns generate incorrect code 16973 * [135]14567 long double and va_arg complex args 16974 * [136]14715 Altivec stack layout may overlap gpr save with stack 16975 temps 16976 * [137]14902 (libstdc++) Stream checking functions fail when -pthread 16977 option is used. 16978 * [138]14924 Compiler ICE on valid code 16979 * [139]14960 -maltivec affects vector return with -mabi=no-altivec 16980 * [140]15106 vector varargs failure passing from altivec to 16981 non-altivec code for -m32 16982 * [141]16026 ICE in function.c:4804, assign_parms, when -mpowerpc64 & 16983 half-word operation 16984 * [142]15191 -maltivec -mabi=no-altivec results in mis-aligned lvx 16985 and stvx 16986 * [143]15662 Segmentation fault when an exception is thrown - even if 16987 try and catch are specified 16988 16989 s390-specific 16990 16991 * [144]15054 Bad code due to overlapping stack temporaries 16992 16993 SPARC-specific 16994 16995 * [145]15783 ICE with union assignment in 64-bit mode 16996 * [146]15626 GCC 3.4 emits "ld: warning: relocation error: 16997 R_SPARC_UA32" 16998 16999 x86-64-specific 17000 17001 * [147]14326 boehm-gc hardcodes to 3DNow! prefetch for x86_64 17002 * [148]14723 Backported -march=nocona from mainline 17003 * [149]15290 __float128 failed to pass to function properly 17004 17005 Cygwin/Mingw32-specific 17006 17007 * [150]15250 Option -mms-bitfields support on GCC 3.4 is not 17008 conformant to MS layout 17009 * [151]15551 -mtune=pentium4 -O2 with sjlj EH breaks stack probe 17010 worker on windows32 targets 17011 17012 Bugs specific to embedded processors 17013 17014 * [152]8309 [m68k] -m5200 produces erroneous SImode set of short 17015 varaible on stack 17016 * [153]13250 [SH] Gcc code for rotation clobbers the register, but 17017 gcc continues to use the register as if it was not clobbered 17018 * [154]13803 [coldfire] movqi operand constraints too restrictivefor 17019 TARGET_COLDFIRE 17020 * [155]14093 [SH] ICE for code when using -mhitachi option in SH 17021 * [156]14457 [m6811hc] ICE with simple c++ source 17022 * [157]14542 [m6811hc] ICE on simple source 17023 * [158]15100 [SH] cc1plus got hang-up on 17024 libstdc++-v3/testsuite/abi_check.cc 17025 * [159]15296 [CRIS] Delayed branch scheduling causing invalid code on 17026 cris-* 17027 * [160]15396 [SH] ICE with -O2 -fPIC 17028 * [161]15782 [coldfire] m68k_output_mi_thunk emits wrong code for 17029 ColdFire 17030 17031 Testsuite problems (compiler not affected) 17032 17033 * [162]11610 libstdc++ testcases 27_io/* don't work properly remotely 17034 * [163]15488 (libstdc++) possibly insufficient file permissions for 17035 executing test suite 17036 * [164]15489 (libstdc++) testsuite_files determined incorrectly 17037 17038 Documentation bugs 17039 17040 * [165]13928 (libstdc++) no whatis info in some man pages generated 17041 by doxygen 17042 * [166]14150 Ada documentation out of date 17043 * [167]14949 (c++) Need to document method visibility changes 17044 * [168]15123 libstdc++-doc: Allocators.3 manpage is empty 17045 __________________________________________________________________ 17046 17047 GCC 3.4.2 17048 17049 Bug Fixes 17050 17051 This section lists the problem reports (PRs) from GCC's bug tracking 17052 system that are known to be fixed in the 3.4.2 release. This list might 17053 not be complete (that is, it is possible that some PRs that have been 17054 fixed are not listed here). 17055 17056 Bootstrap failures and issues 17057 17058 * [169]16469 [mips-sgi-irix5.3] bootstrap fails in 17059 libstdc++-v3/testsuite 17060 * [170]16344 [hppa-linux-gnu] libstdc++'s PCH built by 17061 profiledbootstrap does not work with the built compiler 17062 * [171]16842 [Solaris/x86] mkheaders can not find mkheaders.conf 17063 17064 Multi-platform internal compiler errors (ICEs) 17065 17066 * [172]12608 (c++) ICE: expected class 't', have 'x' (error_mark) in 17067 cp_parser_class_specifier, in cp/parser.c 17068 * [173]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 17069 * [174]15461 (c++) ICE due to NRV and inlining 17070 * [175]15890 (c++) ICE in c_expand_expr, in c-common.c 17071 * [176]16180 ICE: segmentation fault in RTL optimization 17072 * [177]16224 (c++) ICE in write_unscoped_name (template/namespace) 17073 * [178]16408 ICE: in delete_insn, in cfgrtl.c 17074 * [179]16529 (c++) ICE for: namespace-alias shall not be declared as 17075 the name of any other entity 17076 * [180]16698 (c++) ICE with exceptions and declaration of __cxa_throw 17077 * [181]16706 (c++) ICE in finish_member_declaration, in 17078 cp/semantics.c 17079 * [182]16810 (c++) Legal C++ program with cast gives ICE in 17080 build_ptrmemfunc 17081 * [183]16851 (c++) ICE when throwing a comma expression 17082 * [184]16870 (c++) Boost.Spirit causes ICE in tsubst, in cp/pt.c 17083 * [185]16904 (c++) ICE in finish_class_member_access_expr, in 17084 cp/typeck.c 17085 * [186]16905 (c++) ICE (segfault) with exceptions 17086 * [187]16964 (c++) ICE in cp_parser_class_specifier due to 17087 redefinition 17088 * [188]17068 (c++) ICE: tree check: expected class 'd', have 'x' 17089 (identifier_node) in dependent_template_p, in cp/pt.c 17090 17091 Preprocessor bugs 17092 17093 * [189]16366 Preprocessor option -remap causes memory corruption 17094 17095 Optimization 17096 17097 * [190]15345 unreferenced nested inline functions not optimized away 17098 * [191]16590 Incorrect execution when compiling with -O2 17099 * [192]16693 Bitwise AND is lost when used within a cast to an enum 17100 of the same precision 17101 * [193]17078 Jump into if(0) substatement fails 17102 17103 Problems in generated debug information 17104 17105 * [194]13956 incorrect stabs for nested local variables 17106 17107 C front end bugs 17108 17109 * [195]16684 GCC should not warn about redundant redeclarations of 17110 built-ins 17111 17112 C++ compiler and library 17113 17114 * [196]12658 Thread safety problems in locale::global() and 17115 locale::locale() 17116 * [197]13092 g++ accepts invalid pointer-to-member conversion 17117 * [198]15320 Excessive memory consumption 17118 * [199]16246 Incorrect template argument deduction 17119 * [200]16273 Memory exhausted when using nested classes and virtual 17120 functions 17121 * [201]16401 ostringstream in gcc 3.4.x very slow for big data 17122 * [202]16411 undefined reference to 17123 __gnu_cxx::stdio_sync_filebuf<char, std::char_traits<char> 17124 >::file() 17125 * [203]16489 G++ incorrectly rejects use of a null constant integral 17126 expression as a null constant pointer 17127 * [204]16618 offsetof fails with constant member 17128 * [205]16637 syntax error reported for valid input code 17129 * [206]16717 __attribute__((constructor)) broken in C++ 17130 * [207]16813 compiler error in DEBUG version of range insertion 17131 std::map::insert 17132 * [208]16853 pointer-to-member initialization from incompatible one 17133 accepted 17134 * [209]16889 ambiguity is not detected 17135 * [210]16959 Segmentation fault in ios_base::sync_with_stdio 17136 17137 Java compiler and library 17138 17139 * [211]7587 direct threaded interpreter not thread-safe 17140 * [212]16473 ServerSocket accept() leaks file descriptors 17141 * [213]16478 Hash synchronization deadlock with finalizers 17142 17143 Alpha-specific 17144 17145 * [214]10695 ICE in dwarf2out_frame_debug_expr, in dwarf2out.c 17146 * [215]16974 could not split insn (ice in final_scan_insn, in 17147 final.c) 17148 17149 x86-specific 17150 17151 * [216]16298 ICE in output_operand 17152 * [217]17113 ICE with SSE2 intrinsics 17153 17154 x86-64 specific 17155 17156 * [218]14697 libstdc++ couldn't find 32bit libgcc_s 17157 17158 MIPS-specific 17159 17160 * [219]15869 [mips64] No NOP after LW (with -mips1 -O0) 17161 * [220]16325 [mips64] value profiling clobbers gp on mips 17162 * [221]16357 [mipsisa64-elf] ICE copying 7 bytes between extern 17163 char[]s 17164 * [222]16380 [mips64] Use of uninitialised register after dbra 17165 conversion 17166 * [223]16407 [mips64] Unaligned access to local variables 17167 * [224]16643 [mips64] verify_local_live_at_start ICE after 17168 crossjumping & cfgcleanup 17169 17170 ARM-specific 17171 17172 * [225]15927 THUMB -O2: strength-reduced iteration variable ends up 17173 off by 1 17174 * [226]15948 THUMB: ICE with non-commutative cbranch 17175 * [227]17019 THUMB: bad switch statement in md code for 17176 addsi3_cbranch_scratch 17177 17178 IA64-specific 17179 17180 * [228]16130 ICE on valid code: in bundling, in config/ia64/ia64.c 17181 (-mtune=merced) 17182 * [229]16142 ICE on valid code: in bundling, in config/ia64/ia64.c 17183 (-mtune=itanium) 17184 * [230]16278 Gcc failed to build Linux kernel with -mtune=merced 17185 * [231]16414 ICE on valid code: typo in comparison of asm_noperands 17186 result 17187 * [232]16445 ICE on valid code: don't count ignored insns 17188 * [233]16490 ICE (segfault) while compiling with -fprofile-use 17189 * [234]16683 ia64 does not honor SUBTARGET_EXTRA_SPECS 17190 17191 PowerPC-specific 17192 17193 * [235]16195 (ppc64): Miscompilation of GCC 3.3.x by 3.4.x 17194 * [236]16239 ICE on ppc64 (mozilla 1.7 compile, -O1 -fno-exceptions 17195 issue) 17196 17197 SPARC-specific 17198 17199 * [237]16199 ICE while compiling apache 2.0.49 17200 * [238]16416 -m64 doesn't imply -mcpu=v9 anymore 17201 * [239]16430 ICE when returning non-C aggregates larger than 16 bytes 17202 17203 Bugs specific to embedded processors 17204 17205 * [240]16379 [m32r] can't output large model function call of memcpy 17206 * [241]17093 [m32r] ICE with -msdata=use -O0 17207 * [242]17119 [m32r] ICE at switch case 0x8000 17208 17209 DJGPP-specific 17210 17211 * [243]15928 libstdc++ in 3.4.x doesn't cross-compile for djgpp 17212 17213 Alpha Tru64-specific 17214 17215 * [244]16210 libstdc++ gratuitously omits "long long" I/O 17216 17217 Testsuite, documentation issues (compiler is not affected): 17218 17219 * [245]15488 (libstdc++) possibly insufficient file permissions for 17220 executing test suite 17221 * [246]16250 ada/doctools runs makeinfo even in release tarball 17222 __________________________________________________________________ 17223 17224 GCC 3.4.3 17225 17226 This is the [247]list of problem reports (PRs) from GCC's bug tracking 17227 system that are known to be fixed in the 3.4.3 release. This list might 17228 not be complete (that is, it is possible that some PRs that have been 17229 fixed are not listed here). 17230 17231 Bootstrap failures 17232 17233 * [248]17369 [ia64] Bootstrap failure with binutils-2.15.90.0.1.1 17234 * [249]17850 [arm-elf] bootstrap failure - libstdc++ uses strtold 17235 when undeclared 17236 17237 Internal compiler errors (ICEs) affecting multiple platforms 17238 17239 * [250]13948 (java) GCJ segmentation fault while compiling GL4Java 17240 .class files 17241 * [251]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 17242 * [252]16301 (c++) ICE when "strong" attribute is attached to a using 17243 directive 17244 * [253]16566 ICE with flexible arrays 17245 * [254]17023 ICE with nested functions in parameter declaration 17246 * [255]17027 ICE with noreturn function in loop at -O2 17247 * [256]17524 ICE in grokdeclarator, in cp/decl.c 17248 * [257]17826 (c++) ICE in cp_tree_equal 17249 17250 C and optimization bugs 17251 17252 * [258]15526 -ftrapv aborts on 0 * (-1) 17253 * [259]16999 #ident stopped working 17254 * [260]17503 quadratic behaviour in invalid_mode_change_p 17255 * [261]17581 Long long arithmetic fails inside a switch/case 17256 statement when compiled with -O2 17257 * [262]18129 -fwritable-strings doesn't work 17258 17259 C++ compiler and library bugs 17260 17261 * [263]10975 incorrect initial ostringstream::tellp() 17262 * [264]11722 Unbuffered filebuf::sgetn is slow 17263 * [265]14534 Unrecognizing static function as a template parameter 17264 when its return value is also templated 17265 * [266]15172 Copy constructor optimization in aggregate 17266 initialization 17267 * [267]15786 Bad error message for frequently occuring error. 17268 * [268]16162 Rejects valid member-template-definition 17269 * [269]16612 empty basic_strings can't live in shared memory 17270 * [270]16715 std::basic_iostream is instantiated when used, even 17271 though instantiations are already contained in libstdc++ 17272 * [271]16848 code in /ext/demangle.h appears broken 17273 * [272]17132 GCC fails to eliminate function template specialization 17274 when argument deduction fails 17275 * [273]17259 One more _S_leaf incorrectly qualified with _RopeRep:: 17276 in ropeimpl.h 17277 * [274]17327 use of `enumeral_type' in template type unification 17278 * [275]17393 "unused variable '._0'" warning with -Wall 17279 * [276]17501 Confusion with member templates 17280 * [277]17537 g++ not passing -lstdc++ to linker when all command line 17281 arguments are libraries 17282 * [278]17585 usage of unqualified name of static member from within 17283 class not allowed 17284 * [279]17821 Poor diagnostic for using "." instead of "->" 17285 * [280]17829 wrong error: call of overloaded function is ambiguous 17286 * [281]17851 Misleading diagnostic for invalid function declarations 17287 with undeclared types 17288 * [282]17976 Destructor is called twice 17289 * [283]18020 rejects valid definition of enum value in template 17290 * [284]18093 bogus conflict in namespace aliasing 17291 * [285]18140 C++ parser bug when using >> in templates 17292 17293 Fortran 17294 17295 * [286]17541 data statements with double precision constants fail 17296 17297 x86-specific 17298 17299 * [287]17853 -O2 ICE for MMX testcase 17300 17301 SPARC-specific 17302 17303 * [288]17245 ICE compiling gsl-1.5 statistics/lag1.c 17304 17305 Darwin-specific 17306 17307 * [289]17167 FATAL:Symbol L_foo$stub already defined. 17308 17309 AIX-specific 17310 17311 * [290]17277 could not catch an exception when specified -maix64 17312 17313 Solaris-specific 17314 17315 * [291]17505 <cmath> calls acosf(), ceilf(), and other functions 17316 missing from system libraries 17317 17318 HP/UX specific: 17319 17320 * [292]17684 /usr/ccs/bin/ld: Can't create libgcc_s.sl 17321 17322 ARM-specific 17323 17324 * [293]17384 ICE with mode attribute on structures 17325 17326 MIPS-specific 17327 17328 * [294]17770 No NOP after LWL with -mips1 17329 17330 Other embedded target specific 17331 17332 * [295]11476 [arc-elf] gcc ICE on newlib's vfprintf.c 17333 * [296]14064 [avr-elf] -fdata-sections triggers ICE 17334 * [297]14678 [m68hc11-elf] gcc ICE 17335 * [298]15583 [powerpc-rtems] powerpc-rtems lacks __USE_INIT_FINI__ 17336 * [299]15790 [i686-coff] Alignment error building gcc with i686-coff 17337 target 17338 * [300]15886 [SH] Miscompilation with -O2 -fPIC 17339 * [301]16884 [avr-elf] [fweb related] bug while initializing 17340 variables 17341 17342 Bugs relating to debugger support 17343 17344 * [302]13841 missing debug info for _Complex function arguments 17345 * [303]15860 [big-endian targets] No DW_AT_location debug info is 17346 emitted for formal arguments to a function that uses "register" 17347 qualifiers 17348 17349 Testsuite issues (compiler not affected) 17350 17351 * [304]17465 Testsuite in libffi overrides LD_LIBRARY_PATH 17352 * [305]17469 Testsuite in libstdc++ overrides LD_LIBRARY_PATH 17353 * [306]18138 [mips-sgi-irix6.5] libgcc_s.so.1 not found by 64-bit 17354 testsuite 17355 17356 Documentation 17357 17358 * [307]15498 typo in gcc manual: non-existing locale example en_UK, 17359 should be en_GB 17360 * [308]15747 [mips-sgi-irix5.3] /bin/sh hangs during bootstrap: 17361 document broken shell 17362 * [309]16406 USE_LD_AS_NEEDED undocumented 17363 __________________________________________________________________ 17364 17365 GCC 3.4.4 17366 17367 This is the [310]list of problem reports (PRs) from GCC's bug tracking 17368 system that are known to be fixed in the 3.4.4 release. This list might 17369 not be complete (that is, it is possible that some PRs that have been 17370 fixed are not listed here). 17371 __________________________________________________________________ 17372 17373 GCC 3.4.5 17374 17375 This is the [311]list of problem reports (PRs) from GCC's bug tracking 17376 system that are known to be fixed in the 3.4.5 release. This list might 17377 not be complete (that is, it is possible that some PRs that have been 17378 fixed are not listed here). 17379 17380 Bootstrap issues 17381 17382 * [312]24688 sco_math fixincl breaks math.h 17383 17384 C compiler bugs 17385 17386 * [313]17188 struct Foo { } redefinition 17387 * [314]20187 wrong code for ((unsigned char)(unsigned long 17388 long)((a?a:1)&(a*b)))?0:1) 17389 * [315]21873 infinite warning loop on bad array initializer 17390 * [316]21899 enum definition accepts values to be overriden 17391 * [317]22061 ICE in find_function_data, in function.c 17392 * [318]22308 Failure to diagnose violation of constraint 6.516p2 17393 * [319]22458 ICE on missing brace 17394 * [320]22589 ICE casting to long long 17395 * [321]24101 Segfault with preprocessed source 17396 17397 C++ compiler and library bugs 17398 17399 * [322]10611 operations on vector mode not recognized in C++ 17400 * [323]13377 unexpected behavior of namespace usage directive 17401 * [324]16002 Strange error message with new parser 17402 * [325]17413 local classes as template argument 17403 * [326]17609 spurious error message after using keyword 17404 * [327]17618 ICE in cp_convert_to_pointer, in cp/cvt.c 17405 * [328]18124 ICE with invalid template template parameter 17406 * [329]18155 typedef in template declaration not rejected 17407 * [330]18177 ICE with const_cast for undeclared variable 17408 * [331]18368 C++ error message regression 17409 * [332]16378 ICE when returning a copy of a packed member 17410 * [333]18466 int ::i; accepted 17411 * [334]18512 ICE on invalid usage of template base class 17412 * [335]18454 ICE when returning undefined type 17413 * [336]18738 typename not allowed with non-dependent qualified name 17414 * [337]18803 rejects access to operator() in template 17415 * [338]19004 ICE in uses_template_parms, in cp/pt.c 17416 * [339]19208 Spurious error about variably modified type 17417 * [340]18253 bad error message / ICE for invalid template parameter 17418 * [341]19608 ICE after friend function definition in local class 17419 * [342]19884 ICE on explicit instantiation of a non-template 17420 constructor 17421 * [343]20153 ICE when C++ template function contains anonymous union 17422 * [344]20563 Infinite loop in diagnostic (and ice after error 17423 message) 17424 * [345]20789 ICE with incomplete type in template 17425 * [346]21336 Internal compiler error when using custom new operators 17426 * [347]21768 ICE in error message due to violation of coding 17427 conventions 17428 * [348]21853 constness of pointer to data member ignored 17429 * [349]21903 Default argument of template function causes a 17430 compile-time error 17431 * [350]21983 multiple diagnostics 17432 * [351]21987 New testsuite failure 17433 g++.dg/warn/conversion-function-1.C 17434 * [352]22153 ICE on invalid template specialization 17435 * [353]22172 Internal compiler error, seg fault. 17436 * [354]21286 filebuf::xsgetn vs pipes 17437 * [355]22233 ICE with wrong number of template parameters 17438 * [356]22508 ICE after invalid operator new 17439 * [357]22545 ICE with pointer to class member & user defined 17440 conversion operator 17441 * [358]23528 Wrong default allocator in ext/hash_map 17442 * [359]23550 char_traits requirements/1.cc test bad math 17443 * [360]23586 Bad diagnostic for invalid namespace-name 17444 * [361]23624 ICE in invert_truthvalue, in fold-const.c 17445 * [362]23639 Bad error message: not a member of '<declaration error>' 17446 * [363]23797 ICE on typename outside template 17447 * [364]23965 Bogus error message: no matching function for call to 17448 'foo(<type error>)' 17449 * [365]24052 &#`label_decl' not supported by dump_expr#<expression 17450 error> 17451 * [366]24580 virtual base class cause exception not to be caught 17452 17453 Problems in generated debug information 17454 17455 * [367]24267 Bad DWARF for altivec vectors 17456 17457 Optimizations issues 17458 17459 * [368]17810 ICE in verify_local_live_at_start 17460 * [369]17860 Wrong generated code for loop with varying bound 17461 * [370]21709 ICE on compile-time complex NaN 17462 * [371]21964 broken tail call at -O2 or more 17463 * [372]22167 Strange optimization bug when using -Os 17464 * [373]22619 Compilation failure for real_const_1.f and 17465 real_const_2.f90 17466 * [374]23241 Invalid code generated for comparison of uchar to 255 17467 * [375]23478 Miscompilation due to reloading of a var that is also 17468 used in EH pad 17469 * [376]24470 segmentation fault in cc1plus when compiling with -O 17470 * [377]24950 ICE in operand_subword_force 17471 17472 Precompiled headers problems 17473 17474 * [378]14400 Cannot compile qt-x11-free-3.3.0 17475 * [379]14940 PCH largefile test fails on various platforms 17476 17477 Preprocessor bugs 17478 17479 * [380]20239 ICE on empty preprocessed input 17480 * [381]15220 "gcc -E -MM -MG" reports missing system headers in 17481 source directory 17482 17483 Testsuite issues 17484 17485 * [382]19275 gcc.dg/20020919-1.c fails with -fpic/-fPIC on 17486 i686-pc-linux-gnu 17487 17488 Alpha specific 17489 17490 * [383]21888 bootstrap failure with linker relaxation enabled 17491 17492 ARM specific 17493 17494 * [384]15342 [arm-linux]: ICE in verify_local_live_at_start 17495 * [385]23985 Memory aliasing information incorrect in inlined memcpy 17496 17497 ColdFile specific 17498 17499 * [386]16719 Illegal move of byte into address register causes 17500 compiler to ICE 17501 17502 HPPA specific 17503 17504 * [387]21723 ICE while building libgfortran 17505 * [388]21841 -mhp-ld/-mgnu-ld documentation 17506 17507 IA-64 specific 17508 17509 * [389]23644 IA-64 hardware models and configuration options 17510 documentation error 17511 * [390]24718 Shared libgcc not used for linking by default 17512 17513 M68000 specific 17514 17515 * [391]18421 ICE in reload_cse_simplify_operands, in postreload.c 17516 17517 MIPS specific 17518 17519 * [392]20621 ICE in change_address_1, in emit-rtl.c 17520 17521 PowerPC and PowerPC64 specific 17522 17523 * [393]18583 error on valid code: const 17524 __attribute__((altivec(vector__))) doesn't work in arrays 17525 * [394]20191 ICE in reload_cse_simplify_operands 17526 * [395]22083 AIX: TARGET_C99_FUNCTIONS is wrongly defined 17527 * [396]23070 CALL_V4_CLEAR_FP_ARGS flag not properly set 17528 * [397]23404 gij trashes args of functions with more than 8 fp args 17529 * [398]23539 C & C++ compiler generating misaligned references 17530 regardless of compiler flags 17531 * [399]24102 floatdisf2_internal2 broken 17532 * [400]24465 -mminimal-toc miscompilation of __thread vars 17533 17534 Solaris specific 17535 17536 * [401]19933 Problem with define of HUGE_VAL in math_c99 17537 * [402]21889 Native Solaris assembler cannot grok DTP-relative debug 17538 symbols 17539 17540 SPARC specific 17541 17542 * [403]19300 PCH failures on sparc-linux 17543 * [404]20301 Assembler labels have a leading "-" 17544 * [405]20673 C PCH testsuite assembly comparison failure 17545 17546 x86 and x86_64 specific 17547 17548 * [406]18582 ICE with arrays of type V2DF 17549 * [407]19340 Compilation SEGFAULTs with -O1 -fschedule-insns2 17550 -fsched2-use-traces 17551 * [408]21716 ICE in reg-stack.c's swap_rtx_condition 17552 * [409]24315 amd64 fails -fpeephole2 17553 __________________________________________________________________ 17554 17555 GCC 3.4.6 17556 17557 This is the [410]list of problem reports (PRs) from GCC's bug tracking 17558 system that are known to be fixed in the 3.4.6 release. This list might 17559 not be complete (that is, it is possible that some PRs that have been 17560 fixed are not listed here). 17561 17562 17563 For questions related to the use of GCC, please consult these web 17564 pages and the [411]GCC manuals. If that fails, the 17565 [412]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 17566 web pages and the development of GCC are welcome on our developer 17567 list at [413]gcc (a] gcc.gnu.org. All of [414]our lists have public 17568 archives. 17569 17570 Copyright (C) [415]Free Software Foundation, Inc. Verbatim copying and 17571 distribution of this entire article is permitted in any medium, 17572 provided this notice is preserved. 17573 17574 These pages are [416]maintained by the GCC team. Last modified 17575 2023-01-27. 17576 17577 References 17578 17579 1. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6 17580 2. http://gcc.gnu.org/gcc-3.4/changes.html#cplusplus 17581 3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems 17582 4. http://gcc.gnu.org/gcc-3.4/changes.html#obsolete_systems 17583 5. http://gcc.gnu.org/gcc-3.4/mips-abi.html 17584 6. http://gcc.gnu.org/gcc-3.4/sparc-abi.html 17585 7. https://www.boost.org/ 17586 8. https://gcc.gnu.org/PR11953 17587 9. https://gcc.gnu.org/PR8361 17588 10. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Other-Builtins.html#Other%20Builtins 17589 11. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_closed.html#209 17590 12. http://gcc.gnu.org/bugs/#cxx_rvalbind 17591 13. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 17592 14. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 17593 15. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 17594 16. http://www.gnu.org/software/classpath/ 17595 17. https://www.eclipse.org/ 17596 18. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/g77/News.html 17597 19. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Alpha-Built-in-Functions.html 17598 20. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Processor-pipeline-description.html 17599 21. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Comparison-of-the-two-descriptions.html 17600 22. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Processor-pipeline-description.html 17601 23. http://gcc.gnu.org/gcc-3.4/mips-abi.html 17602 24. http://gcc.gnu.org/gcc-3.4/powerpc-abi.html 17603 25. http://gcc.gnu.org/gcc-3.4/sparc-abi.html 17604 26. https://gcc.gnu.org/bugzilla/buglist.cgi?short_desc_type=notregexp&short_desc=%5C%5B3%5C.4.*%5BRr%5Degression&target_milestone=3.4.0&bug_status=RESOLVED&resolution=FIXED 17605 27. https://gcc.gnu.org/PR10129 17606 28. https://gcc.gnu.org/PR14576 17607 29. https://gcc.gnu.org/PR14760 17608 30. 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https://gcc.gnu.org/PR20673 17984 406. https://gcc.gnu.org/PR18582 17985 407. https://gcc.gnu.org/PR19340 17986 408. https://gcc.gnu.org/PR21716 17987 409. https://gcc.gnu.org/PR24315 17988 410. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.6 17989 411. https://gcc.gnu.org/onlinedocs/ 17990 412. mailto:gcc-help (a] gcc.gnu.org 17991 413. mailto:gcc (a] gcc.gnu.org 17992 414. https://gcc.gnu.org/lists.html 17993 415. https://www.fsf.org/ 17994 416. https://gcc.gnu.org/about.html 17995 ====================================================================== 17996 http://gcc.gnu.org/gcc-3.3/index.html 17997 17998 GCC 3.3 Release Series 17999 18000 (This release series is no longer supported.) 18001 18002 May 03, 2005 18003 18004 The [1]GNU project and the GCC developers are pleased to announce the 18005 release of GCC 3.3.6. 18006 18007 This release is a bug-fix release, containing fixes for regressions in 18008 GCC 3.3.5 relative to previous releases of GCC. 18009 18010 This release is the last of the series 3.3.x. 18011 18012 The GCC 3.3 release series includes numerous [2]new features, 18013 improvements, bug fixes, and other changes, thanks to an [3]amazing 18014 group of volunteers. 18015 18016 Release History 18017 18018 GCC 3.3.6 18019 May 3, 2005 ([4]changes) 18020 18021 GCC 3.3.5 18022 September 30, 2004 ([5]changes) 18023 18024 GCC 3.3.4 18025 May 31, 2004 ([6]changes) 18026 18027 GCC 3.3.3 18028 February 14, 2004 ([7]changes) 18029 18030 GCC 3.3.2 18031 October 16, 2003 ([8]changes) 18032 18033 GCC 3.3.1 18034 August 8, 2003 ([9]changes) 18035 18036 GCC 3.3 18037 May 14, 2003 ([10]changes) 18038 18039 References and Acknowledgements 18040 18041 GCC used to stand for the GNU C Compiler, but since the compiler 18042 supports several other languages aside from C, it now stands for the 18043 GNU Compiler Collection. 18044 18045 A list of [11]successful builds is updated as new information becomes 18046 available. 18047 18048 The GCC developers would like to thank the numerous people that have 18049 contributed new features, improvements, bug fixes, and other changes as 18050 well as test results to GCC. This [12]amazing group of volunteers is 18051 what makes GCC successful. 18052 18053 For additional information about GCC please refer to the [13]GCC 18054 project web site or contact the [14]GCC development mailing list. 18055 18056 To obtain GCC please use [15]our mirror sites, or our CVS server. 18057 18058 18059 For questions related to the use of GCC, please consult these web 18060 pages and the [16]GCC manuals. If that fails, the 18061 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 18062 web pages and the development of GCC are welcome on our developer 18063 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 18064 archives. 18065 18066 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 18067 distribution of this entire article is permitted in any medium, 18068 provided this notice is preserved. 18069 18070 These pages are [21]maintained by the GCC team. Last modified 18071 2022-10-26. 18072 18073 References 18074 18075 1. http://www.gnu.org/ 18076 2. http://gcc.gnu.org/gcc-3.3/changes.html 18077 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 18078 4. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 18079 5. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.5 18080 6. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.4 18081 7. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.3 18082 8. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.2 18083 9. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.1 18084 10. http://gcc.gnu.org/gcc-3.3/changes.html 18085 11. http://gcc.gnu.org/gcc-3.3/buildstat.html 18086 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 18087 13. http://gcc.gnu.org/index.html 18088 14. mailto:gcc (a] gcc.gnu.org 18089 15. http://gcc.gnu.org/mirrors.html 18090 16. https://gcc.gnu.org/onlinedocs/ 18091 17. mailto:gcc-help (a] gcc.gnu.org 18092 18. mailto:gcc (a] gcc.gnu.org 18093 19. https://gcc.gnu.org/lists.html 18094 20. https://www.fsf.org/ 18095 21. https://gcc.gnu.org/about.html 18096 ====================================================================== 18097 http://gcc.gnu.org/gcc-3.3/changes.html 18098 18099 GCC 3.3 Release Series 18100 Changes, New Features, and Fixes 18101 18102 The latest release in the 3.3 release series is [1]GCC 3.3.6. 18103 18104 Caveats 18105 18106 * The preprocessor no longer accepts multi-line string literals. They 18107 were deprecated in 3.0, 3.1, and 3.2. 18108 * The preprocessor no longer supports the -A- switch when appearing 18109 alone. -A- followed by an assertion is still supported. 18110 * Support for all the systems [2]obsoleted in GCC 3.1 has been 18111 removed from GCC 3.3. See below for a [3]list of systems which are 18112 obsoleted in this release. 18113 * Checking for null format arguments has been decoupled from the rest 18114 of the format checking mechanism. Programs which use the format 18115 attribute may regain this functionality by using the new [4]nonnull 18116 function attribute. Note that all functions for which GCC has a 18117 built-in format attribute, an appropriate built-in nonnull 18118 attribute is also applied. 18119 * The DWARF (version 1) debugging format has been deprecated and will 18120 be removed in a future version of GCC. Version 2 of the DWARF 18121 debugging format will continue to be supported for the foreseeable 18122 future. 18123 * The C and Objective-C compilers no longer accept the "Naming Types" 18124 extension (typedef foo = bar); it was already unavailable in C++. 18125 Code which uses it will need to be changed to use the "typeof" 18126 extension instead: typedef typeof(bar) foo. (We have removed this 18127 extension without a period of deprecation because it has caused the 18128 compiler to crash since version 3.0 and no one noticed until very 18129 recently. Thus we conclude it is not in widespread use.) 18130 * The -traditional C compiler option has been removed. It was 18131 deprecated in 3.1 and 3.2. (Traditional preprocessing remains 18132 available.) The <varargs.h> header, used for writing variadic 18133 functions in traditional C, still exists but will produce an error 18134 message if used. 18135 * GCC 3.3.1 automatically places zero-initialized variables in the 18136 .bss section on some operating systems. Versions of GNU Emacs up to 18137 (and including) 21.3 will not work correctly when using this 18138 optimization; you can use -fno-zero-initialized-in-bss to disable 18139 it. 18140 18141 General Optimizer Improvements 18142 18143 * A new scheme for accurately describing processor pipelines, the 18144 [5]DFA scheduler, has been added. 18145 * Pavel Nejedly, Charles University Prague, has contributed new file 18146 format used by the edge coverage profiler (-fprofile-arcs). 18147 The new format is robust and diagnoses common mistakes where 18148 profiles from different versions (or compilations) of the program 18149 are combined resulting in nonsensical profiles and slow code to 18150 produced with profile feedback. Additionally this format allows 18151 extra data to be gathered. Currently, overall statistics are 18152 produced helping optimizers to identify hot spots of a program 18153 globally replacing the old intra-procedural scheme and resulting in 18154 better code. Note that the gcov tool from older GCC versions will 18155 not be able to parse the profiles generated by GCC 3.3 and vice 18156 versa. 18157 * Jan Hubicka, SuSE Labs, has contributed a new superblock formation 18158 pass enabled using -ftracer. This pass simplifies the control flow 18159 of functions allowing other optimizations to do better job. 18160 He also contributed the function reordering pass 18161 (-freorder-functions) to optimize function placement using profile 18162 feedback. 18163 18164 New Languages and Language specific improvements 18165 18166 C/ObjC/C++ 18167 18168 * The preprocessor now accepts directives within macro arguments. It 18169 processes them just as if they had not been within macro arguments. 18170 * The separate ISO and traditional preprocessors have been completely 18171 removed. The front end handles either type of preprocessed output 18172 if necessary. 18173 * In C99 mode preprocessor arithmetic is done in the precision of the 18174 target's intmax_t, as required by that standard. 18175 * The preprocessor can now copy comments inside macros to the output 18176 file when the macro is expanded. This feature, enabled using the 18177 -CC option, is intended for use by applications which place 18178 metadata or directives inside comments, such as lint. 18179 * The method of constructing the list of directories to be searched 18180 for header files has been revised. If a directory named by a -I 18181 option is a standard system include directory, the option is 18182 ignored to ensure that the default search order for system 18183 directories and the special treatment of system header files are 18184 not defeated. 18185 * A few more [6]ISO C99 features now work correctly. 18186 * A new function attribute, nonnull, has been added which allows 18187 pointer arguments to functions to be specified as requiring a 18188 non-null value. The compiler currently uses this information to 18189 issue a warning when it detects a null value passed in such an 18190 argument slot. 18191 * A new type attribute, may_alias, has been added. Accesses to 18192 objects with types with this attribute are not subjected to 18193 type-based alias analysis, but are instead assumed to be able to 18194 alias any other type of objects, just like the char type. 18195 18196 C++ 18197 18198 * Type based alias analysis has been implemented for C++ aggregate 18199 types. 18200 18201 Objective-C 18202 18203 * Generate an error if Objective-C objects are passed by value in 18204 function and method calls. 18205 * When -Wselector is used, check the whole list of selectors at the 18206 end of compilation, and emit a warning if a @selector() is not 18207 known. 18208 * Define __NEXT_RUNTIME__ when compiling for the NeXT runtime. 18209 * No longer need to include objc/objc-class.h to compile self calls 18210 in class methods (NeXT runtime only). 18211 * New -Wundeclared-selector option. 18212 * Removed selector bloating which was causing object files to be 10% 18213 bigger on average (GNU runtime only). 18214 * Using at run time @protocol() objects has been fixed in certain 18215 situations (GNU runtime only). 18216 * Type checking has been fixed and improved in many situations 18217 involving protocols. 18218 18219 Java 18220 18221 * The java.sql and javax.sql packages now implement the JDBC 3.0 (JDK 18222 1.4) API. 18223 * The JDK 1.4 assert facility has been implemented. 18224 * The bytecode interpreter is now direct threaded and thus faster. 18225 18226 Fortran 18227 18228 * Fortran improvements are listed in [7]the Fortran documentation. 18229 18230 Ada 18231 18232 * Ada tasking now works with glibc 2.3.x threading libraries. 18233 18234 New Targets and Target Specific Improvements 18235 18236 * The following changes have been made to the HP-PA port: 18237 + The port now defaults to scheduling for the PA8000 series of 18238 processors. 18239 + Scheduling support for the PA7300 processor has been added. 18240 + The 32-bit port now supports weak symbols under HP-UX 11. 18241 + The handling of initializers and finalizers has been improved 18242 under HP-UX 11. The 64-bit port no longer uses collect2. 18243 + Dwarf2 EH support has been added to the 32-bit GNU/Linux port. 18244 + ABI fixes to correct the passing of small structures by value. 18245 * The SPARC, HP-PA, SH4, and x86/pentium ports have been converted to 18246 use the DFA processor pipeline description. 18247 * The following NetBSD configurations for the SuperH processor family 18248 have been added: 18249 + SH3, big-endian, sh-*-netbsdelf* 18250 + SH3, little-endian, shle-*-netbsdelf* 18251 + SH5, SHmedia, big-endian, 32-bit default, sh5-*-netbsd* 18252 + SH5, SHmedia, little-endian, 32-bit default, sh5le-*-netbsd* 18253 + SH5, SHmedia, big-endian, 64-bit default, sh64-*-netbsd* 18254 + SH5, SHmedia, little-endian, 64-bit default, sh64le-*-netbsd* 18255 * The following changes have been made to the IA-32/x86-64 port: 18256 + SSE2 and 3dNOW! intrinsics are now supported. 18257 + Support for thread local storage has been added to the IA-32 18258 and x86-64 ports. 18259 + The x86-64 port has been significantly improved. 18260 * The following changes have been made to the MIPS port: 18261 + All configurations now accept the -mabi switch. Note that you 18262 will need appropriate multilibs for this option to work 18263 properly. 18264 + ELF configurations will always pass an ABI flag to the 18265 assembler, except when the MIPS EABI is selected. 18266 + -mabi=64 no longer selects MIPS IV code. 18267 + The -mcpu option, which was deprecated in 3.1 and 3.2, has 18268 been removed from this release. 18269 + -march now changes the core ISA level. In previous releases, 18270 it would change the use of processor-specific extensions, but 18271 would leave the core ISA unchanged. For example, mips64-elf 18272 -march=r8000 will now generate MIPS IV code. 18273 + Under most configurations, -mipsN now acts as a synonym for 18274 -march. 18275 + There are some new preprocessor macros to describe the -march 18276 and -mtune settings. See the documentation of those options 18277 for details. 18278 + Support for the NEC VR-Series processors has been added. This 18279 includes the 54xx, 5500, and 41xx series. 18280 + Support for the Sandcraft sr71k processor has been added. 18281 * The following changes have been made to the S/390 port: 18282 + Support to build the Java runtime libraries has been added. 18283 Java is now enabled by default on s390-*-linux* and 18284 s390x-*-linux* targets. 18285 + Multilib support for the s390x-*-linux* target has been added; 18286 this allows to build 31-bit binaries using the -m31 option. 18287 + Support for thread local storage has been added. 18288 + Inline assembler code may now use the 'Q' constraint to 18289 specify memory operands without index register. 18290 + Various platform-specific performance improvements have been 18291 implemented; in particular, the compiler now uses the BRANCH 18292 ON COUNT family of instructions and makes more frequent use of 18293 the TEST UNDER MASK family of instructions. 18294 * The following changes have been made to the PowerPC port: 18295 + Support for IBM Power4 processor added. 18296 + Support for Motorola e500 SPE added. 18297 + Support for AIX 5.2 added. 18298 + Function and Data sections now supported on AIX. 18299 + Sibcall optimizations added. 18300 * The support for H8 Tiny is added to the H8/300 port with -mn. 18301 18302 Obsolete Systems 18303 18304 Support for a number of older systems has been declared obsolete in GCC 18305 3.3. Unless there is activity to revive them, the next release of GCC 18306 will have their sources permanently removed. 18307 18308 All configurations of the following processor architectures have been 18309 declared obsolete: 18310 * Matsushita MN10200, mn10200-*-* 18311 * Motorola 88000, m88k-*-* 18312 * IBM ROMP, romp-*-* 18313 18314 Also, some individual systems have been obsoleted: 18315 * Alpha 18316 + Interix, alpha*-*-interix* 18317 + Linux libc1, alpha*-*-linux*libc1* 18318 + Linux ECOFF, alpha*-*-linux*ecoff* 18319 * ARM 18320 + Generic a.out, arm*-*-aout* 18321 + Conix, arm*-*-conix* 18322 + "Old ABI," arm*-*-oabi 18323 + StrongARM/COFF, strongarm-*-coff* 18324 * HPPA (PA-RISC) 18325 + Generic OSF, hppa1.0-*-osf* 18326 + Generic BSD, hppa1.0-*-bsd* 18327 + HP/UX versions 7, 8, and 9, hppa1.[01]-*-hpux[789]* 18328 + HiUX, hppa*-*-hiux* 18329 + Mach Lites, hppa*-*-lites* 18330 * Intel 386 family 18331 + Windows NT 3.x, i?86-*-win32 18332 * MC68000 family 18333 + HP systems, m68000-hp-bsd* and m68k-hp-bsd* 18334 + Sun systems, m68000-sun-sunos*, m68k-sun-sunos*, and 18335 m68k-sun-mach* 18336 + AT&T systems, m68000-att-sysv* 18337 + Atari systems, m68k-atari-sysv* 18338 + Motorola systems, m68k-motorola-sysv* 18339 + NCR systems, m68k-ncr-sysv* 18340 + Plexus systems, m68k-plexus-sysv* 18341 + Commodore systems, m68k-cbm-sysv* 18342 + Citicorp TTI, m68k-tti-* 18343 + Unos, m68k-crds-unos* 18344 + Concurrent RTU, m68k-ccur-rtu* 18345 + Linux a.out, m68k-*-linux*aout* 18346 + Linux libc1, m68k-*-linux*libc1* 18347 + pSOS, m68k-*-psos* 18348 * MIPS 18349 + Generic ECOFF, mips*-*-ecoff* 18350 + SINIX, mips-sni-sysv4 18351 + Orion RTEMS, mips64orion-*-rtems* 18352 * National Semiconductor 32000 18353 + OpenBSD, ns32k-*-openbsd* 18354 * POWER (aka RS/6000) and PowerPC 18355 + AIX versions 1, 2, and 3, rs6000-ibm-aix[123]* 18356 + Bull BOSX, rs6000-bull-bosx 18357 + Generic Mach, rs6000-*-mach* 18358 + Generic SysV, powerpc*-*-sysv* 18359 + Linux libc1, powerpc*-*-linux*libc1* 18360 * Sun SPARC 18361 + Generic a.out, sparc-*-aout*, sparclet-*-aout*, 18362 sparclite-*-aout*, and sparc86x-*-aout* 18363 + NetBSD a.out, sparc-*-netbsd*aout* 18364 + Generic BSD, sparc-*-bsd* 18365 + ChorusOS, sparc-*-chorusos* 18366 + Linux a.out, sparc-*-linux*aout* 18367 + Linux libc1, sparc-*-linux*libc1* 18368 + LynxOS, sparc-*-lynxos* 18369 + Solaris on HAL hardware, sparc-hal-solaris2* 18370 + SunOS versions 3 and 4, sparc-*-sunos[34]* 18371 * NEC V850 18372 + RTEMS, v850-*-rtems* 18373 * VAX 18374 + VMS, vax-*-vms* 18375 18376 Documentation improvements 18377 18378 Other significant improvements 18379 18380 * Almost all front-end dependencies in the compiler have been 18381 separated out into a set of language hooks. This should make adding 18382 a new front end clearer and easier. 18383 * One effect of removing the separate preprocessor is a small 18384 increase in the robustness of the compiler in general, and the 18385 maintainability of target descriptions. Previously target-specific 18386 built-in macros and others, such as __FAST_MATH__, had to be 18387 handled with so-called specs that were hard to maintain. Often they 18388 would fail to behave properly when conflicting options were 18389 supplied on the command line, and define macros in the user's 18390 namespace even when strict ISO compliance was requested. 18391 Integrating the preprocessor has cleanly solved these issues. 18392 * The Makefile suite now supports redirection of make install by 18393 means of the variable DESTDIR. 18394 __________________________________________________________________ 18395 18396 GCC 3.3 18397 18398 Detailed release notes for the GCC 3.3 release follow. 18399 18400 Bug Fixes 18401 18402 bootstrap failures 18403 18404 * [8]10140 cross compiler build failures: missing __mempcpy (DUP: 18405 [9]10198,[10]10338) 18406 18407 Internal compiler errors (multi-platform) 18408 18409 * [11]3581 large string causes segmentation fault in cc1 18410 * [12]4382 __builtin_{set,long}jmp with -O3 can crash the compiler 18411 * [13]5533 (c++) ICE when processing std::accumulate(begin, end, 18412 init, invalid_op) 18413 * [14]6387 -fpic -gdwarf-2 -g1 combination gives ICE in dwarf2out 18414 * [15]6412 (c++) ICE in retrieve_specialization 18415 * [16]6620 (c++) partial template specialization causes an ICE 18416 (segmentation fault) 18417 * [17]6663 (c++) ICE with attribute aligned 18418 * [18]7068 ICE with incomplete types 18419 * [19]7083 (c++) ICE using -gstabs with dodgy class derivation 18420 * [20]7647 (c++) ICE when data member has the name of the enclosing 18421 class 18422 * [21]7675 ICE in fixup_var_refs_1 18423 * [22]7718 'complex' template instantiation causes ICE 18424 * [23]8116 (c++) ICE in member template function 18425 * [24]8358 (ada) Ada compiler accesses freed memory, crashes 18426 * [25]8511 (c++) ICE: (hopefully) reproducible cc1plus segmentation 18427 fault 18428 * [26]8564 (c++) ICE in find_function_data, in function.c 18429 * [27]8660 (c++) template overloading ICE in tsubst_expr, in cp/pt.c 18430 * [28]8766 (c++) ICE after failed initialization of static template 18431 variable 18432 * [29]8803 ICE in instantiate_virtual_regs_1, in function.c 18433 * [30]8846 (c++) ICE after diagnostic if fr_FR@euro locale is set 18434 * [31]8906 (c++) ICE (Segmentation fault) when parsing nested-class 18435 definition 18436 * [32]9216 (c++) ICE on missing template parameter 18437 * [33]9261 (c++) ICE in arg_assoc, in cp/decl2.c 18438 * [34]9263 (fortran) ICE caused by invalid PARAMETER in implied DO 18439 loop 18440 * [35]9429 (c++) ICE in template instantiation with a pointered new 18441 operator 18442 * [36]9516 Internal error when using a big array 18443 * [37]9600 (c++) ICE with typedefs in template class 18444 * [38]9629 (c++) virtual inheritance segfault 18445 * [39]9672 (c++) ICE: Error reporting routines re-entered 18446 * [40]9749 (c++) ICE in write_expression on invalid function 18447 prototype 18448 * [41]9794 (fortran) ICE: floating point exception during constant 18449 folding 18450 * [42]9829 (c++) Missing colon in nested namespace usage causes ICE 18451 * [43]9916 (c++) ICE with noreturn function in ?: statement 18452 * [44]9936 ICE with local function and variable-length 2d array 18453 * [45]10262 (c++) cc1plus crashes with large generated code 18454 * [46]10278 (c++) ICE in parser for invalid code 18455 * [47]10446 (c++) ICE on definition of nonexistent member function of 18456 nested class in a class template 18457 * [48]10451 (c++) ICE in grokdeclarator on spurious mutable 18458 declaration 18459 * [49]10506 (c++) ICE in build_new at cp/init.c with 18460 -fkeep-inline-functions and multiple inheritance 18461 * [50]10549 (c++) ICE in store_bit_field on bitfields that exceed the 18462 precision of the declared type 18463 18464 Optimization bugs 18465 18466 * [51]2001 Inordinately long compile times in reload CSE regs 18467 * [52]2391 Exponential compilation time explosion in combine 18468 * [53]2960 Duplicate loop conditions even with -Os 18469 * [54]4046 redundant conditional branch 18470 * [55]6405 Loop-unrolling related performance regressions 18471 * [56]6798 very long compile time with large case-statement 18472 * [57]6871 const objects shouldn't be moved to .bss 18473 * [58]6909 problem w/ -Os on modified loop-2c.c test case 18474 * [59]7189 gcc -O2 -Wall does not print ``control reaches end of 18475 non-void function'' warning 18476 * [60]7642 optimization problem with signbit() 18477 * [61]8634 incorrect code for inlining of memcpy under -O2 18478 * [62]8750 Cygwin prolog generation erroneously emitting __alloca as 18479 regular function call 18480 18481 C front end 18482 18483 * [63]2161 long if-else cascade overflows parser stack 18484 * [64]4319 short accepted on typedef'd char 18485 * [65]8602 incorrect line numbers in warning messages when using 18486 inline functions 18487 * [66]9177 -fdump-translation-unit: C front end deletes function_decl 18488 AST nodes and breaks debugging dumps 18489 * [67]9853 miscompilation of non-constant structure initializer 18490 18491 c++ compiler and library 18492 18493 * [68]45 legal template specialization code is rejected (DUP: 18494 [69]3784) 18495 * [70]764 lookup failure: friend operator and dereferencing a pointer 18496 and templates (DUP: [71]5116) 18497 * [72]2862 gcc accepts invalid explicit instantiation syntax (DUP: 18498 2863) 18499 * [73]3663 G++ doesn't check access control during template 18500 instantiation 18501 * [74]3797 gcc fails to emit explicit specialization of a template 18502 member 18503 * [75]3948 Two destructors are called when no copy destructor is 18504 defined (ABI change) 18505 * [76]4137 Conversion operator within template is not accepted 18506 * [77]4361 bogus ambiguity taking the address of a member template 18507 * [78]4802 g++ accepts illegal template code (access to private 18508 member; DUP: [79]5837) 18509 * [80]4803 inline function is used but never defined, and g++ does 18510 not object 18511 * [81]5094 Partial specialization cannot be friend? 18512 * [82]5730 complex<double>::norm() -- huge slowdown from egcs-2.91.66 18513 * [83]6713 Regression wrt 3.0.4: g++ -O2 leads to seg fault at run 18514 time 18515 * [84]7015 certain __asm__ constructs rejected 18516 * [85]7086 compile time regression (quadratic behavior in 18517 fixup_var_refs) 18518 * [86]7099 G++ doesn't set the noreturn attribute on std::exit and 18519 std::abort 18520 * [87]7247 copy constructor missing when inlining enabled (invalid 18521 optimization?) 18522 * [88]7441 string array initialization compilation time regression 18523 from seconds to minutes 18524 * [89]7768 __PRETTY_FUNCTION__ for template destructor is wrong 18525 * [90]7804 bad printing of floating point constant in warning message 18526 * [91]8099 Friend classes and template specializations 18527 * [92]8117 member function pointers and multiple inheritance 18528 * [93]8205 using declaration and multiple inheritance 18529 * [94]8645 unnecessary non-zero checks in stl_tree.h 18530 * [95]8724 explicit destructor call for incomplete class allowed 18531 * [96]8805 compile time regression with many member variables 18532 * [97]8691 -O3 and -fno-implicit-templates are incompatible 18533 * [98]8700 unhelpful error message for binding temp to reference 18534 * [99]8724 explicit destructor call for incomplete class allowed 18535 * [100]8949 numeric_limits<>::denorm_min() and is_iec559 problems 18536 * [101]9016 Failure to consistently constant fold "constant" C++ 18537 objects 18538 * [102]9053 g++ confused about ambiguity of overloaded function 18539 templates 18540 * [103]9152 undefined virtual thunks 18541 * [104]9182 basic_filebuf<> does not report errors in codecvt<>::out 18542 * [105]9297 data corruption due to codegen bug (when copying.) 18543 * [106]9318 i/ostream::operator>>/<<(streambuf*) broken 18544 * [107]9320 Incorrect usage of traits_type::int_type in stdio_filebuf 18545 * [108]9400 bogus -Wshadow warning: shadowed declaration of this in 18546 local classes 18547 * [109]9424 i/ostream::operator>>/<<(streambuf*) drops characters 18548 * [110]9425 filebuf::pbackfail broken (DUP: [111]9439) 18549 * [112]9474 GCC freezes in compiling a weird code mixing <iostream> 18550 and <iostream.h> 18551 * [113]9548 Incorrect results from setf(ios::fixed) and precision(-1) 18552 [114][DR 231] 18553 * [115]9555 ostream inserters fail to set badbit on exception 18554 * [116]9561 ostream inserters rethrow exception of wrong type 18555 * [117]9563 ostream::sentry returns true after a failed preparation 18556 * [118]9582 one-definition rule violation in std::allocator 18557 * [119]9622 __PRETTY_FUNCTION__ incorrect in template destructors 18558 * [120]9683 bug in initialization chains for static const variables 18559 from template classes 18560 * [121]9791 -Woverloaded-virtual reports hiding of destructor 18561 * [122]9817 collate::compare doesn't handle nul characters 18562 * [123]9825 filebuf::sputbackc breaks sbumpc 18563 * [124]9826 operator>>(basic_istream, basic_string) fails to compile 18564 with custom traits 18565 * [125]9924 Multiple using statements for builtin functions not 18566 allowed 18567 * [126]9946 destructor is not called for temporary object 18568 * [127]9964 filebuf::close() sometimes fails to close file 18569 * [128]9988 filebuf::overflow writes EOF to file 18570 * [129]10033 optimization breaks polymorphic references w/ typeid 18571 operator 18572 * [130]10097 filebuf::underflow drops characters 18573 * [131]10132 filebuf destructor can throw exceptions 18574 * [132]10180 gcc fails to warn about non-inlined function 18575 * [133]10199 method parametrized by template does not work everywhere 18576 * [134]10300 use of array-new (nothrow) in segfaults on NULL return 18577 * [135]10427 Stack corruption with variable-length automatic arrays 18578 and virtual destructors 18579 * [136]10503 Compilation never stops in fixed_type_or_null 18580 18581 Objective-C 18582 18583 * [137]5956 selectors aren't matched properly when added to the 18584 selector table 18585 18586 Fortran compiler and library 18587 18588 * [138]1832 list directed i/o overflow hangs, -fbounds-check doesn't 18589 detect 18590 * [139]3924 g77 generates code that is rejected by GAS if COFF debug 18591 info requested 18592 * [140]5634 doc: explain that configure --prefix=~/... does not work 18593 * [141]6367 multiple repeat counts confuse namelist read into array 18594 * [142]6491 Logical operations error on logicals when using 18595 -fugly-logint 18596 * [143]6742 Generation of C++ Prototype for FORTRAN and extern "C" 18597 * [144]7113 Failure of g77.f-torture/execute/f90-intrinsic-bit.f -Os 18598 on irix6.5 18599 * [145]7236 OPEN(...,RECL=nnn,...) without ACCESS='DIRECT' should 18600 assume a direct access file 18601 * [146]7278 g77 "bug"; the executable misbehaves (with -O2 18602 -fno-automatic) 18603 * [147]7384 DATE_AND_TIME milliseconds field inactive on Windows 18604 * [148]7388 Incorrect output with 0-based array of characters 18605 * [149]8587 Double complex zero ** double precision number -> NaN 18606 instead of zero 18607 * [150]9038 -ffixed-line-length-none -x f77-cpp-input gives: Warning: 18608 unknown register name line-length-none 18609 * [151]10197 Direct access files not unformatted by default 18610 18611 Java compiler and library 18612 18613 * [152]6005 gcj fails to build rhug on alpha 18614 * [153]6389 System.getProperty("") should always throw an 18615 IllegalArgumentException 18616 * [154]6576 java.util.ResourceBundle.getResource ignores locale 18617 * [155]6652 new java.io.File("").getCanonicalFile() throws exception 18618 * [156]7060 getMethod() doesn't search super interface 18619 * [157]7073 bytecode interpreter gives wrong answer for interface 18620 getSuperclass() 18621 * [158]7180 possible bug in 18622 javax.naming.spi.NamingManager.getPlusPath() 18623 * [159]7416 java.security startup refs "GNU libgcj.security" 18624 * [160]7570 Runtime.exec with null envp: child doesn't inherit parent 18625 env (DUP: [161]7578) 18626 * [162]7611 Internal error while compiling libjava with -O 18627 * [163]7709 NullPointerException in _Jv_ResolvePoolEntry 18628 * [164]7766 ZipInputStream.available returns 0 immediately after 18629 construction 18630 * [165]7785 Calendar.getTimeInMillis/setTimeInMillis should be public 18631 * [166]7786 TimeZone.getDSTSavings() from JDK1.4 not implemented 18632 * [167]8142 '$' in class names vs. dlopen 'dynamic string tokens' 18633 * [168]8234 ZipInputStream chokes when InputStream.read() returns 18634 small chunks 18635 * [169]8415 reflection bug: exception info for Method 18636 * [170]8481 java.Random.nextInt(int) may return negative 18637 * [171]8593 Error reading GZIPped files with BufferedReader 18638 * [172]8759 java.beans.Introspector has no flushCaches() or 18639 flushFromCaches() methods 18640 * [173]8997 spin() calls Thread.sleep 18641 * [174]9253 on win32, java.io.File.listFiles("C:\\") returns pwd 18642 instead of the root content of C: 18643 * [175]9254 java::lang::Object::wait(), threads-win32.cc returns 18644 wrong return codes 18645 * [176]9271 Severe bias in java.security.SecureRandom 18646 18647 Ada compiler and library 18648 18649 * [177]6767 make gnatlib-shared fails on -laddr2line 18650 * [178]9911 gnatmake fails to link when GCC configured with 18651 --with-sjlj-exceptions=yes 18652 * [179]10020 Can't bootstrap gcc on AIX with Ada enabled 18653 * [180]10546 Ada tasking not working on Red Hat 9 18654 18655 preprocessor 18656 18657 * [181]7029 preprocessor should ignore #warning with -M 18658 18659 ARM-specific 18660 18661 * [182]2903 [arm] Optimization bug with long long arithmetic 18662 * [183]7873 arm-linux-gcc fails when assigning address to a bit field 18663 18664 FreeBSD-specific 18665 18666 * [184]7680 float functions undefined in math.h/cmath with #define 18667 _XOPEN_SOURCE 18668 18669 HP-UX or HP-PA-specific 18670 18671 * [185]8705 [HP-PA] ICE in emit_move_insn_1, in expr.c 18672 * [186]9986 [HP-UX] Incorrect transformation of fputs_unlocked to 18673 fputc_unlocked 18674 * [187]10056 [HP-PA] ICE at -O2 when building c++ code from doxygen 18675 18676 m68hc11-specific 18677 18678 * [188]6744 Bad assembler code generated: reference to pseudo 18679 register z 18680 * [189]7361 Internal compiler error in reload_cse_simplify_operands, 18681 in reload1.c 18682 18683 MIPS-specific 18684 18685 * [190]9496 [mips-linux] bug in optimizer? 18686 18687 PowerPC-specific 18688 18689 * [191]7067 -Os with -mcpu=powerpc optimizes for speed (?) instead of 18690 space 18691 * [192]8480 reload ICEs for LAPACK code on powerpc64-linux 18692 * [193]8784 [AIX] Internal compiler error in simplify_gen_subreg 18693 * [194]10315 [powerpc] ICE: in extract_insn, in recog.c 18694 18695 SPARC-specific 18696 18697 * [195]10267 (documentation) Wrong build instructions for 18698 *-*-solaris2* 18699 18700 x86-specific (Intel/AMD) 18701 18702 * [196]7916 ICE in instantiate_virtual_register_1 18703 * [197]7926 (c++) i486 instructions in header files make c++ programs 18704 crash on i386 18705 * [198]8555 ICE in gen_split_1231 18706 * [199]8994 ICE with -O -march=pentium4 18707 * [200]9426 ICE with -fssa -funroll-loops -fprofile-arcs 18708 * [201]9806 ICE in inline assembly with -fPIC flag 18709 * [202]10077 gcc -msse2 generates movd to move dwords between xmm 18710 regs 18711 * [203]10233 64-bit comparison only comparing bottom 32-bits 18712 * [204]10286 type-punning doesn't work with __m64 and -O 18713 * [205]10308 [x86] ICE with -O -fgcse or -O2 18714 __________________________________________________________________ 18715 18716 GCC 3.3.1 18717 18718 Bug Fixes 18719 18720 This section lists the problem reports (PRs) from GCC's bug tracking 18721 system that are known to be fixed in the 3.3.1 release. This list might 18722 not be complete (that is, it is possible that some PRs that have been 18723 fixed are not listed here). 18724 18725 Bootstrap failures 18726 18727 * [206]11272 [Solaris] make bootstrap fails while building libstdc++ 18728 18729 Internal compiler errors (multi-platform) 18730 18731 * [207]5754 ICE on invalid nested template class 18732 * [208]6597 ICE in set_mem_alias_set compiling Qt with -O2 on ia64 18733 and --enable-checking 18734 * [209]6949 (c++) ICE in tsubst_decl, in cp/pt.c 18735 * [210]7053 (c++) ICE when declaring a function already defined as a 18736 friend method of a template class 18737 * [211]8164 (c++) ICE when using different const expressions as 18738 template parameter 18739 * [212]8384 (c++) ICE in is_base_type, in dwarf2out.c 18740 * [213]9559 (c++) ICE with invalid initialization of a static const 18741 * [214]9649 (c++) ICE in finish_member_declaration, in cp/semantics.c 18742 when redeclaring a static member variable 18743 * [215]9864 (fortran) ICE in add_abstract_origin_attribute, in 18744 dwarfout.c with -g -O -finline-functions 18745 * [216]10432 (c++) ICE in poplevel, in cp/decl.c 18746 * [217]10475 ICE in subreg_highpart_offset for code with long long 18747 * [218]10635 (c++) ICE when dereferencing an incomplete type casted 18748 from a void pointer 18749 * [219]10661 (c++) ICE in instantiate_decl, in cp/pt.c while 18750 instantiating static member variables 18751 * [220]10700 ICE in copy_to_mode_reg on 64-bit targets 18752 * [221]10712 (c++) ICE in constructor_name_full, in cp/decl2.c 18753 * [222]10796 (c++) ICE when defining an enum with two values: -1 and 18754 MAX_INT_64BIT 18755 * [223]10890 ICE in merge_assigned_reloads building Linux 2.4.2x 18756 sched.c 18757 * [224]10939 (c++) ICE with template code 18758 * [225]10956 (c++) ICE when specializing a template member function 18759 of a template class, in tsubst, in cp/pt.c 18760 * [226]11041 (c++) ICE: const myclass &x = *x; (when operator*() 18761 defined) 18762 * [227]11059 (c++) ICE with empty union 18763 * [228]11083 (c++) ICE in commit_one_edge_insertion, in cfgrtl.c with 18764 -O2 -fnon-call-exceptions 18765 * [229]11105 (c++) ICE in mangle_conv_op_name_for_type 18766 * [230]11149 (c++) ICE on error when instantiation with call function 18767 of a base type 18768 * [231]11228 (c++) ICE on new-expression using array operator new and 18769 default-initialization 18770 * [232]11282 (c++) Infinite memory usage after syntax error 18771 * [233]11301 (fortran) ICE with -fno-globals 18772 * [234]11308 (c++) ICE when using an enum type name as if it were a 18773 class or namespace 18774 * [235]11473 (c++) ICE with -gstabs when empty struct inherits from 18775 an empty struct 18776 * [236]11503 (c++) ICE when instantiating template with ADDR_EXPR 18777 * [237]11513 (c++) ICE in push_template_decl_real, in cp/pt.c: 18778 template member functions 18779 18780 Optimization bugs 18781 18782 * [238]11198 -O2 -frename-registers generates wrong code (aliasing 18783 problem) 18784 * [239]11304 Wrong code production with -fomit-frame-pointer 18785 * [240]11381 volatile memory access optimized away 18786 * [241]11536 [strength-reduce] -O2 optimization produces wrong code 18787 * [242]11557 constant folding bug generates wrong code 18788 18789 C front end 18790 18791 * [243]5897 No warning for statement after return 18792 * [244]11279 DWARF-2 output mishandles large enums 18793 18794 Preprocessor bugs 18795 18796 * [245]11022 no warning for non-compatible macro redefinition 18797 18798 C++ compiler and library 18799 18800 * [246]2330 static_cast<>() to a private base is allowed 18801 * [247]5388 Incorrect message "operands to ?: have different types" 18802 * [248]5390 Libiberty fails to demangle multi-digit template 18803 parameters 18804 * [249]7877 Incorrect parameter passing to specializations of member 18805 function templates 18806 * [250]9393 Anonymous namespaces and compiling the same file twice 18807 * [251]10032 -pedantic converts some errors to warnings 18808 * [252]10468 const typeof(x) is non-const, but only in templates 18809 * [253]10527 confused error message with "new int()" parameter 18810 initializer 18811 * [254]10679 parameter MIN_INLINE_INSNS is not honored 18812 * [255]10682 gcc chokes on a typedef for an enum inside a class 18813 template 18814 * [256]10689 pow(std::complex(0),1/3) returns (nan, nan) instead of 18815 0. 18816 * [257]10845 template member function (with nested template as 18817 parameter) cannot be called anymore if another unrelated template 18818 member function is defined 18819 * [258]10849 Cannot define an out-of-class specialization of a 18820 private nested template class 18821 * [259]10888 Suppress -Winline warnings for system headers 18822 * [260]10929 -Winline warns about functions for which no definition 18823 is visible 18824 * [261]10931 valid conversion static_cast<const unsigned 18825 int&>(lvalue-of-type-int) is rejected 18826 * [262]10940 Bad code with explicit specialization 18827 * [263]10968 If member function implicitly instantiated, explicit 18828 instantiation of class fails to instantiate it 18829 * [264]10990 Cannot convert with dynamic_cast<> to a private base 18830 class from within a member function 18831 * [265]11039 Bad interaction between implicit typename deprecation 18832 and friendship 18833 * [266]11062 (libstdc++) avoid __attribute__ ((unused)); say 18834 "__unused__" instead 18835 * [267]11095 C++ iostream manipulator causes segfault when called 18836 with negative argument 18837 * [268]11098 g++ doesn't emit complete debugging information for 18838 local variables in destructors 18839 * [269]11137 GNU/Linux shared library constructors not called unless 18840 there's one global object 18841 * [270]11154 spurious ambiguity report for template class 18842 specialization 18843 * [271]11329 Compiler cannot find user defined implicit typecast 18844 * [272]11332 Spurious error with casts in ?: expression 18845 * [273]11431 static_cast behavior with subclasses when default 18846 constructor available 18847 * [274]11528 money_get facet does not accept "$.00" as valid 18848 * [275]11546 Type lookup problems in out-of-line definition of a 18849 class doubly nested from a template class 18850 * [276]11567 C++ code containing templated member function with same 18851 name as pure virtual member function results in linking failure 18852 * [277]11645 Failure to deal with using and private inheritance 18853 18854 Java compiler and library 18855 18856 * [278]5179 Qualified static field access doesn't initialize its 18857 class 18858 * [279]8204 gcj -O2 to native reorders certain instructions 18859 improperly 18860 * [280]10838 java.io.ObjectInputStream syntax error 18861 * [281]10886 The RMI registry that comes with GCJ does not work 18862 correctly 18863 * [282]11349 JNDI URL context factories not located correctly 18864 18865 x86-specific (Intel/AMD) 18866 18867 * [283]4823 ICE on inline assembly code 18868 * [284]8878 miscompilation with -O and SSE 18869 * [285]9815 (c++ library) atomicity.h - fails to compile with -O3 18870 -masm=intel 18871 * [286]10402 (inline assembly) [x86] ICE in merge_assigned_reloads, 18872 in reload1.c 18873 * [287]10504 ICE with SSE2 code and -O3 -mcpu=pentium4 -msse2 18874 * [288]10673 ICE for x86-64 on freebsd libc vfprintf.c source 18875 * [289]11044 [x86] out of range loop instructions for FP code on K6 18876 * [290]11089 ICE: instantiate_virtual_regs_lossage while using SSE 18877 built-ins 18878 * [291]11420 [x86_64] gcc generates invalid asm code when "-O -fPIC" 18879 is used 18880 18881 SPARC- or Solaris- specific 18882 18883 * [292]9362 solaris 'as' dies when fed .s and "-gstabs" 18884 * [293]10142 [SPARC64] gcc produces wrong code when passing 18885 structures by value 18886 * [294]10663 New configure check aborts with Sun tools. 18887 * [295]10835 combinatorial explosion in scheduler on HyperSPARC 18888 * [296]10876 ICE in calculate_giv_inc when building KDE 18889 * [297]10955 wrong code at -O3 for structure argument in context of 18890 structure return 18891 * [298]11018 -mcpu=ultrasparc busts tar-1.13.25 18892 * [299]11556 [sparc64] ICE in gen_reg_rtx() while compiling 2.6.x 18893 Linux kernel 18894 18895 ia64 specific 18896 18897 * [300]10907 gcc violates the ia64 ABI (GP must be preserved) 18898 * [301]11320 scheduler bug (in machine depended reorganization pass) 18899 * [302]11599 bug with conditional and __builtin_prefetch 18900 18901 PowerPC specific 18902 18903 * [303]9745 [powerpc] gcc mis-compiles libmcrypt (alias problem 18904 during loop) 18905 * [304]10871 error in rs6000_stack_info save_size computation 18906 * [305]11440 gcc mis-compiles c++ code (libkhtml) with -O2, -fno-gcse 18907 cures it 18908 18909 m68k-specific 18910 18911 * [306]7594 [m68k] ICE on legal code associated with simplify-rtx 18912 * [307]10557 [m68k] ICE in subreg_offset_representable_p 18913 * [308]11054 [m68k] ICE in reg_overlap_mentioned_p 18914 18915 ARM-specific 18916 18917 * [309]10834 [arm] GCC 3.3 still generates incorrect instructions for 18918 functions with __attribute__ ((interrupt ("IRQ"))) 18919 * [310]10842 [arm] Clobbered link register is copied to pc under 18920 certain circumstances 18921 * [311]11052 [arm] noce_process_if_block() can lose REG_INC notes 18922 * [312]11183 [arm] ICE in change_address_1 (3.3) / subreg_hard_regno 18923 (3.4) 18924 18925 MIPS-specific 18926 18927 * [313]11084 ICE in propagate_one_insn, in flow.c 18928 18929 SH-specific 18930 18931 * [314]10331 can't compile c++ part of gcc cross compiler for sh-elf 18932 * [315]10413 [SH] ICE in reload_cse_simplify_operands, in reload1.c 18933 * [316]11096 i686-linux to sh-linux cross compiler fails to compile 18934 C++ files 18935 18936 GNU/Linux (or Hurd?) specific 18937 18938 * [317]2873 Bogus fixinclude of stdio.h from glibc 2.2.3 18939 18940 UnixWare specific 18941 18942 * [318]3163 configure bug: gcc/aclocal.m4 mmap test fails on UnixWare 18943 7.1.1 18944 18945 Cygwin (or mingw) specific 18946 18947 * [319]5287 ICE with dllimport attribute 18948 * [320]10148 [MingW/CygWin] Compiler dumps core 18949 18950 DJGPP specific 18951 18952 * [321]8787 GCC fails to emit .intel_syntax when invoked with 18953 -masm=intel on DJGPP 18954 18955 Darwin (and MacOS X) specific 18956 18957 * [322]10900 trampolines crash 18958 18959 Documentation 18960 18961 * [323]1607 (c++) Format attributes on methods undocumented 18962 * [324]4252 Invalid option `-fdump-translation-unit' 18963 * [325]4490 Clarify restrictions on -m96bit-long-double, 18964 -m128bit-long-double 18965 * [326]10355 document an issue with regparm attribute on some systems 18966 (e.g. Solaris) 18967 * [327]10726 (fortran) Documentation for function "IDate Intrinsic 18968 (Unix)" is wrong 18969 * [328]10805 document bug in old version of Sun assembler 18970 * [329]10815 warn against GNU binutils on AIX 18971 * [330]10877 document need for newer binutils on i?86-*-linux-gnu 18972 * [331]11280 Manual incorrect with respect to -freorder-blocks 18973 * [332]11466 Document -mlittle-endian and its restrictions for the 18974 sparc64 port 18975 18976 Testsuite bugs (compiler itself is not affected) 18977 18978 * [333]10737 newer bison causes g++.dg/parse/crash2.C to incorrectly 18979 report failure 18980 * [334]10810 gcc-3.3 fails make check: buffer overrun in 18981 test_demangle.c 18982 __________________________________________________________________ 18983 18984 GCC 3.3.2 18985 18986 Bug Fixes 18987 18988 This section lists the problem reports (PRs) from GCC's bug tracker 18989 that are known to be fixed in the 3.3.2 release. This list might not be 18990 complete (that is, it is possible that some PRs that have been fixed 18991 are not listed here). 18992 18993 Bootstrap failures and problems 18994 18995 * [335]8336 [SCO5] bootstrap config still tries to use COFF options 18996 * [336]9330 [alpha-osf] Bootstrap failure on Compaq Tru64 with 18997 --enable-threads=posix 18998 * [337]9631 [hppa64-linux] gcc-3.3 fails to bootstrap 18999 * [338]9877 fixincludes makes a bad sys/byteorder.h on svr5 (UnixWare 19000 7.1.1) 19001 * [339]11687 xstormy16-elf build fails in libf2c 19002 * [340]12263 [SGI IRIX] bootstrap fails during compile of 19003 libf2c/libI77/backspace.c 19004 * [341]12490 buffer overflow in scan-decls.c (during Solaris 9 19005 fix-header processing) 19006 19007 Internal compiler errors (multi-platform) 19008 19009 * [342]7277 Casting integers to vector types causes ICE 19010 * [343]7939 (c++) ICE on invalid function template specialization 19011 * [344]11063 (c++) ICE on parsing initialization list of const array 19012 member 19013 * [345]11207 ICE with negative index in array element designator 19014 * [346]11522 (fortran) g77 dwarf-2 ICE in 19015 add_abstract_origin_attribute 19016 * [347]11595 (c++) ICE on duplicate label definition 19017 * [348]11646 (c++) ICE in commit_one_edge_insertion with 19018 -fnon-call-exceptions -fgcse -O 19019 * [349]11665 ICE in struct initializer when taking address 19020 * [350]11852 (c++) ICE with bad struct initializer. 19021 * [351]11878 (c++) ICE in cp_expr_size 19022 * [352]11883 ICE with any -O on mercury-generated C code 19023 * [353]11991 (c++) ICE in cxx_incomplete_type_diagnostic, in 19024 cp/typeck2.c when applying typeid operator to template template 19025 parameter 19026 * [354]12146 ICE in lookup_template_function, in cp/pt.c 19027 * [355]12215 ICE in make_label_edge with -fnon-call-exceptions 19028 -fno-gcse -O2 19029 * [356]12369 (c++) ICE with templates and friends 19030 * [357]12446 ICE in emit_move_insn on complicated array reference 19031 * [358]12510 ICE in final_scan_insn 19032 * [359]12544 ICE with large parameters used in nested functions 19033 19034 C and optimization bugs 19035 19036 * [360]9862 spurious warnings with -W -finline-functions 19037 * [361]10962 lookup_field is a linear search on a linked list (can be 19038 slow if large struct) 19039 * [362]11370 -Wunreachable-code gives false complaints 19040 * [363]11637 invalid assembly with -fnon-call-exceptions 19041 * [364]11885 Problem with bitfields in packed structs 19042 * [365]12082 Inappropriate unreachable code warnings 19043 * [366]12180 Inline optimization fails for variadic function 19044 * [367]12340 loop unroller + gcse produces wrong code 19045 19046 C++ compiler and library 19047 19048 * [368]3907 nested template parameter collides with member name 19049 * [369]5293 confusing message when binding a temporary to a reference 19050 * [370]5296 [DR115] Pointers to functions and to template functions 19051 behave differently in deduction 19052 * [371]7939 ICE on function template specialization 19053 * [372]8656 Unable to assign function with __attribute__ and pointer 19054 return type to an appropriate variable 19055 * [373]10147 Confusing error message for invalid template function 19056 argument 19057 * [374]11400 std::search_n() makes assumptions about Size parameter 19058 * [375]11409 issues with using declarations, overloading, and 19059 built-in functions 19060 * [376]11740 ctype<wchar_t>::do_is(mask, wchar_t) doesn't handle 19061 multiple bits in mask 19062 * [377]11786 operator() call on variable in other namespace not 19063 recognized 19064 * [378]11867 static_cast ignores ambiguity 19065 * [379]11928 bug with conversion operators that are typedefs 19066 * [380]12114 Uninitialized memory accessed in dtor 19067 * [381]12163 static_cast + explicit constructor regression 19068 * [382]12181 Wrong code with comma operator and c++ 19069 * [383]12236 regparm and fastcall messes up parameters 19070 * [384]12266 incorrect instantiation of unneeded template during 19071 overload resolution 19072 * [385]12296 istream::peek() doesn't set eofbit 19073 * [386]12298 [sjlj exceptions] Stack unwind destroys 19074 not-yet-constructed object 19075 * [387]12369 ICE with templates and friends 19076 * [388]12337 apparently infinite loop in g++ 19077 * [389]12344 stdcall attribute ignored if function returns a pointer 19078 * [390]12451 missing(late) class forward declaration in cxxabi.h 19079 * [391]12486 g++ accepts invalid use of a qualified name 19080 19081 x86 specific (Intel/AMD) 19082 19083 * [392]8869 [x86 MMX] ICE with const variable optimization and MMX 19084 builtins 19085 * [393]9786 ICE in fixup_abnormal_edges with -fnon-call-exceptions 19086 -O2 19087 * [394]11689 g++3.3 emits un-assembleable code for k6 architecture 19088 * [395]12116 [k6] Invalid assembly output values with X-MAME code 19089 * [396]12070 ICE converting between double and long double with 19090 -msoft-float 19091 19092 ia64-specific 19093 19094 * [397]11184 [ia64 hpux] ICE on __builtin_apply building libobjc 19095 * [398]11535 __builtin_return_address may not work on ia64 19096 * [399]11693 [ia64] ICE in gen_nop_type 19097 * [400]12224 [ia64] Thread-local storage doesn't work 19098 19099 PowerPC-specific 19100 19101 * [401]11087 [powerpc64-linux] GCC miscompiles raid1.c from linux 19102 kernel 19103 * [402]11319 loop miscompiled on ppc32 19104 * [403]11949 ICE Compiler segfault with ffmpeg -maltivec code 19105 19106 SPARC-specific 19107 19108 * [404]11662 wrong code for expr. with cast to long long and 19109 exclusive or 19110 * [405]11965 invalid assembler code for a shift < 32 operation 19111 * [406]12301 (c++) stack corruption when a returned expression throws 19112 an exception 19113 19114 Alpha-specific 19115 19116 * [407]11717 [alpha-linux] unrecognizable insn compiling for.c of 19117 kernel 2.4.22-pre8 19118 19119 HPUX-specific 19120 19121 * [408]11313 problem with #pragma weak and static inline functions 19122 * [409]11712 __STDC_EXT__ not defined for C++ by default anymore? 19123 19124 Solaris specific 19125 19126 * [410]12166 Profiled programs crash if PROFDIR is set 19127 19128 Solaris-x86 specific 19129 19130 * [411]12101 i386 Solaris no longer works with GNU as? 19131 19132 Miscellaneous embedded target-specific bugs 19133 19134 * [412]10988 [m32r-elf] wrong blockmove code with -O3 19135 * [413]11805 [h8300-unknown-coff] [H8300] ICE for simple code with 19136 -O2 19137 * [414]11902 [sh4] spec file improperly inserts rpath even when none 19138 needed 19139 * [415]11903 [sh4] -pthread fails to link due to error in spec file 19140 on sh4 19141 __________________________________________________________________ 19142 19143 GCC 3.3.3 19144 19145 Minor features 19146 19147 In addition to the bug fixes documented below, this release contains 19148 few minor features such as: 19149 * Support for --with-sysroot 19150 * Support for automatic detection of executable stacks 19151 * Support for SSE3 instructions 19152 * Support for thread local storage debugging under GDB on S390 19153 19154 Bug Fixes 19155 19156 This section lists the problem reports (PRs) from GCC's bug tracker 19157 that are known to be fixed in the 3.3.3 release. This list might not be 19158 complete (that is, it is possible that some PRs that have been fixed 19159 are not listed here). 19160 19161 Bootstrap failures and issues 19162 19163 * [416]11890 Building cross gcc-3.3.1 for sparc-sun-solaris2.6 fails 19164 * [417]12399 boehm-gc fails (when building a cross compiler): libtool 19165 unable to infer tagged configuration 19166 * [418]13068 mklibgcc.in doesn't handle multi-level multilib 19167 subdirectories properly 19168 19169 Internal compiler errors (multi-platform) 19170 19171 * [419]10060 ICE (stack overflow) on huge file (300k lines) due to 19172 recursive behaviour of copy_rtx_if_shared, in emit_rtl.c 19173 * [420]10555 (c++) ICE on undefined template argument 19174 * [421]10706 (c++) ICE in mangle_class_name_for_template 19175 * [422]11496 (fortran) error in flow_loops_find when -funroll-loops 19176 active 19177 * [423]11741 ICE in pre_insert_copy_insn, in gcse.c 19178 * [424]12440 GCC crashes during compilation of quicktime4linux 2.0.0 19179 * [425]12632 (fortran) -fbounds-check ICE 19180 * [426]12712 (c++) ICE on short legit C++ code fragment with gcc 19181 3.3.2 19182 * [427]12726 (c++) ICE (segfault) on trivial code 19183 * [428]12890 (c++) ICE on compilation of class with throwing method 19184 * [429]12900 (c++) ICE in rtl_verify_flow_info_1 19185 * [430]13060 (fortran) ICE in fixup_var_refs_1, in function.c on 19186 correct code with -O2 -fno-force-mem 19187 * [431]13289 (c++) ICE in regenerate_decl_from_template on recursive 19188 template 19189 * [432]13318 ICE: floating point exception in the loop optimizer 19190 * [433]13392 (c++) ICE in convert_from_eh_region_ranges_1, in 19191 except.c 19192 * [434]13574 (c++) invalid array default initializer in class lets 19193 gcc consume all memory and die 19194 * [435]13475 ICE on SIMD variables with partial value initialization 19195 * [436]13797 (c++) ICE on invalid template parameter 19196 * [437]13824 (java) gcj SEGV with simple .java program 19197 19198 C and optimization bugs 19199 19200 * [438]8776 loop invariants are not removed (most likely) 19201 * [439]10339 [sparc,ppc,ppc64] Invalid optimization: replacing 19202 strncmp by memcmp 19203 * [440]11350 undefined labels with -Os -fPIC 19204 * [441]12826 Optimizer removes reference through volatile pointer 19205 * [442]12500 stabs debug info: void no longer a predefined / builtin 19206 type 19207 * [443]12941 builtin-bitops-1.c miscompilation (latent bug) 19208 * [444]12953 tree inliner bug (in inline_forbidden_p) and fix 19209 * [445]13041 linux-2.6/sound/core/oss/rate.c miscompiled 19210 * [446]13507 spurious printf format warning 19211 * [447]13382 Type information for const pointer disappears during 19212 optimization. 19213 * [448]13394 noreturn attribute ignored on recursive invokation 19214 * [449]13400 Compiled code crashes storing to read-only location 19215 * [450]13521 Endless loop in calculate_global_regs_live 19216 19217 C++ compiler and library 19218 19219 Some of the bug fixes in this list were made to implement decisions 19220 that the ISO C++ standards committee has made concerning several defect 19221 reports (DRs). Links in the list below point to detailed discussion of 19222 the relevant defect report. 19223 * [451]2094 unimplemented: use of `ptrmem_cst' in template type 19224 unification 19225 * [452]2294 using declaration confusion 19226 * [453]5050 template instantiation depth exceeds limit: recursion 19227 problem? 19228 * [454]9371 Bad exception handling in 19229 i/ostream::operator>>/<<(streambuf*) 19230 * [455]9546 bad exception handling in ostream members 19231 * [456]10081 basic_ios::_M_cache_locale leaves NULL members in the 19232 face of unknown locales 19233 * [457]10093 [458][DR 61] Setting failbit in exceptions doesn't work 19234 * [459]10095 istream::operator>>(int&) sets ios::badbit when 19235 ios::failbit is set. 19236 * [460]11554 Warning about reordering of initializers doesn't mention 19237 location of constructor 19238 * [461]12297 istream::sentry::sentry() handles eof() incorrectly. 19239 * [462]12352 Exception safety problems in src/localename.cc 19240 * [463]12438 Memory leak in locale::combine() 19241 * [464]12540 Memory leak in locale::locale(const char*) 19242 * [465]12594 DRs [466]60 [TC] and [467]63 [TC] not implemented 19243 * [468]12657 Resolution of [469]DR 292 (WP) still unimplemented 19244 * [470]12696 memory eating infinite loop in diagnostics (error 19245 recovery problem) 19246 * [471]12815 Code compiled with optimization behaves unexpectedly 19247 * [472]12862 Conflicts between typedefs/enums and namespace member 19248 declarations 19249 * [473]12926 Wrong value after assignment in initialize list using 19250 bit-fields 19251 * [474]12967 Resolution of [475]DR 300 [WP] still unimplemented 19252 * [476]12971 Resolution of [477]DR 328 [WP] still unimplemented 19253 * [478]13007 basic_streambuf::pubimbue, imbue wrong 19254 * [479]13009 Implicitly-defined assignment operator writes to wrong 19255 memory 19256 * [480]13057 regparm attribute not applied to destructor 19257 * [481]13070 -Wformat option ignored in g++ 19258 * [482]13081 forward template declarations in <complex> let inlining 19259 fail 19260 * [483]13239 Assertion does not seem to work correctly anymore 19261 * [484]13262 "xxx is private within this context" when initializing a 19262 self-contained template class 19263 * [485]13290 simple typo in concept checking for std::generate_n 19264 * [486]13323 Template code does not compile in presence of typedef 19265 * [487]13369 __verify_grouping (and __add_grouping?) not correct 19266 * [488]13371 infinite loop with packed struct and inlining 19267 * [489]13445 Template argument replacement "dereferences" a typedef 19268 * [490]13461 Fails to access protected-ctor from public constant 19269 * [491]13462 Non-standard-conforming type set::pointer 19270 * [492]13478 gcc uses wrong constructor to initialize a const 19271 reference 19272 * [493]13544 "conflicting types" for enums in different scopes 19273 * [494]13650 string::compare should not (always) use 19274 traits_type::length() 19275 * [495]13683 bogus warning about passing non-PODs through ellipsis 19276 * [496]13688 Derived class is denied access to protected base class 19277 member class 19278 * [497]13774 Member variable cleared in virtual multiple inheritance 19279 class 19280 * [498]13884 Protect sstream.tcc from extern template use 19281 19282 Java compiler and library 19283 19284 * [499]10746 [win32] garbage collection crash in GCJ 19285 19286 Objective-C compiler and library 19287 19288 * [500]11433 Crash due to dereferencing null pointer when querying 19289 protocol 19290 19291 Fortran compiler and library 19292 19293 * [501]12633 logical expression gives incorrect result with 19294 -fugly-logint option 19295 * [502]13037 [gcse-lm] g77 generates incorrect code 19296 * [503]13213 Hex constant problem when compiling with -fugly-logint 19297 and -ftypeless-boz 19298 19299 x86-specific (Intel/AMD) 19300 19301 * [504]4490 ICE with -m128bit-long-double 19302 * [505]12292 [x86_64] ICE: RTL check: expected code `const_int', have 19303 `reg' in make_field_assignment, in combine.c 19304 * [506]12441 ICE: can't find a register to spill 19305 * [507]12943 array static-init failure under -fpic, -fPIC 19306 * [508]13608 Incorrect code with -O3 -ffast-math 19307 19308 PowerPC-specific 19309 19310 * [509]11598 testcase gcc.dg/20020118-1.c fails runtime check of 19311 __attribute__((aligned(16))) 19312 * [510]11793 ICE in extract_insn, in recog.c (const_vector's) 19313 * [511]12467 vmsumubm emitted when vmsummbm appropriate (typo in 19314 altivec.md) 19315 * [512]12537 g++ generates writeable text sections 19316 19317 SPARC-specific 19318 19319 * [513]12496 wrong result for __atomic_add(&value, -1) when using -O0 19320 -m64 19321 * [514]12865 mprotect call to make trampoline executable may fail 19322 * [515]13354 ICE in sparc_emit_set_const32 19323 19324 ARM-specific 19325 19326 * [516]10467 [arm] ICE in pre_insert_copy_insn, 19327 19328 ia64-specific 19329 19330 * [517]11226 ICE passing struct arg with two floats 19331 * [518]11227 ICE for _Complex float, _Complex long double args 19332 * [519]12644 GCC 3.3.2 fails to compile glibc on ia64 19333 * [520]13149 build gcc-3.3.2 1305 error:unrecognizable insn 19334 * Various fixes for libunwind 19335 19336 Alpha-specific 19337 19338 * [521]12654 Incorrect comparison code generated for Alpha 19339 * [522]12965 SEGV+ICE in cc1plus on alpha-linux with -O2 19340 * [523]13031 ICE (unrecognizable insn) when building gnome-libs-1.4.2 19341 19342 HPPA-specific 19343 19344 * [524]11634 [hppa] ICE in verify_local_live_at_start, in flow.c 19345 * [525]12158 [hppa] compilation does not terminate at -O1 19346 19347 S390-specific 19348 19349 * [526]11992 Wrong built-in code for memcmp with length 1<<24: only 19350 (1<<24)-1 possible for CLCL-Instruction 19351 19352 SH-specific 19353 19354 * [527]9365 segfault in gen_far_branch (config/sh/sh.c) 19355 * [528]10392 optimizer generates faulty array indexing 19356 * [529]11322 SH profiler outputs multiple definitions of symbol 19357 * [530]13069 gcc/config/sh/rtems.h broken 19358 * [531]13302 Putting a va_list in a struct causes seg fault 19359 * [532]13585 Incorrect optimization of call to sfunc 19360 * Fix inappropriately exported libgcc functions from the shared 19361 library 19362 19363 Other embedded target specific 19364 19365 * [533]8916 [mcore] unsigned char assign gets hosed. 19366 * [534]11576 [h8300] ICE in change_address_1, in emit-rtl.c 19367 * [535]13122 [h8300] local variable gets corrupted by function call 19368 when -fomit-frame-pointer is given 19369 * [536]13256 [cris] strict_low_part mistreated in delay slots 19370 * [537]13373 [mcore] optimization with -frerun-cse-after-loop 19371 -fexpensive-optimizations produces wrong code on mcore 19372 19373 GNU HURD-specific 19374 19375 * [538]12561 gcc/config/t-gnu needs updating to work with 19376 --with-sysroot 19377 19378 Tru64 Unix specific 19379 19380 * [539]6243 testsuite fails almost all tests due to no libintl in 19381 LD_LIBRARY_PATH during test. 19382 * [540]11397 weak aliases broken on Tru64 UNIX 19383 19384 AIX-specific 19385 19386 * [541]12505 build failure due to defines of uchar in cpphash.h and 19387 sys/types.h 19388 * [542]13150 WEAK symbols not exported by collect2 19389 19390 IRIX-specific 19391 19392 * [543]12666 fixincludes problem on IRIX 6.5.19m 19393 19394 Solaris-specific 19395 19396 * [544]12969 Including sys/byteorder.h breaks configure checks 19397 19398 Testsuite problems (compiler is not affected) 19399 19400 * [545]10819 testsuite creates CR+LF on compiler version lines in 19401 test summary files 19402 * [546]11612 abi_check not finding correct libgcc_s.so.1 19403 19404 Miscellaneous 19405 19406 * [547]13211 using -###, incorrect warnings about unused linker file 19407 are produced 19408 __________________________________________________________________ 19409 19410 GCC 3.3.4 19411 19412 This is the [548]list of problem reports (PRs) from GCC's bug tracking 19413 system that are known to be fixed in the 3.3.4 release. This list might 19414 not be complete (that is, it is possible that some PRs that have been 19415 fixed are not listed here). 19416 __________________________________________________________________ 19417 19418 GCC 3.3.5 19419 19420 This is the [549]list of problem reports (PRs) from GCC's bug tracking 19421 system that are known to be fixed in the 3.3.5 release. This list might 19422 not be complete (that is, it is possible that some PRs that have been 19423 fixed are not listed here). 19424 __________________________________________________________________ 19425 19426 GCC 3.3.6 19427 19428 This is the [550]list of problem reports (PRs) from GCC's bug tracking 19429 system that are known to be fixed in the 3.3.6 release. This list might 19430 not be complete (that is, it is possible that some PRs that have been 19431 fixed are not listed here). 19432 19433 19434 For questions related to the use of GCC, please consult these web 19435 pages and the [551]GCC manuals. If that fails, the 19436 [552]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19437 web pages and the development of GCC are welcome on our developer 19438 list at [553]gcc (a] gcc.gnu.org. All of [554]our lists have public 19439 archives. 19440 19441 Copyright (C) [555]Free Software Foundation, Inc. Verbatim copying and 19442 distribution of this entire article is permitted in any medium, 19443 provided this notice is preserved. 19444 19445 These pages are [556]maintained by the GCC team. Last modified 19446 2023-01-19. 19447 19448 References 19449 19450 1. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 19451 2. http://gcc.gnu.org/gcc-3.1/changes.html#obsolete_systems 19452 3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems 19453 4. http://gcc.gnu.org/gcc-3.3/changes.html#nonnull_attribute 19454 5. http://gcc.gnu.org/news/dfa.html 19455 6. http://gcc.gnu.org/c99status.html 19456 7. https://gcc.gnu.org/onlinedocs/gcc-3.3.6/g77/News.html 19457 8. https://gcc.gnu.org/PR10140 19458 9. https://gcc.gnu.org/PR10198 19459 10. https://gcc.gnu.org/PR10338 19460 11. https://gcc.gnu.org/PR3581 19461 12. https://gcc.gnu.org/PR4382 19462 13. https://gcc.gnu.org/PR5533 19463 14. https://gcc.gnu.org/PR6387 19464 15. https://gcc.gnu.org/PR6412 19465 16. https://gcc.gnu.org/PR6620 19466 17. https://gcc.gnu.org/PR6663 19467 18. https://gcc.gnu.org/PR7068 19468 19. https://gcc.gnu.org/PR7083 19469 20. https://gcc.gnu.org/PR7647 19470 21. https://gcc.gnu.org/PR7675 19471 22. 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19834 385. https://gcc.gnu.org/PR12296 19835 386. https://gcc.gnu.org/PR12298 19836 387. https://gcc.gnu.org/PR12369 19837 388. https://gcc.gnu.org/PR12337 19838 389. https://gcc.gnu.org/PR12344 19839 390. https://gcc.gnu.org/PR12451 19840 391. https://gcc.gnu.org/PR12486 19841 392. https://gcc.gnu.org/PR8869 19842 393. https://gcc.gnu.org/PR9786 19843 394. https://gcc.gnu.org/PR11689 19844 395. https://gcc.gnu.org/PR12116 19845 396. https://gcc.gnu.org/PR12070 19846 397. https://gcc.gnu.org/PR11184 19847 398. https://gcc.gnu.org/PR11535 19848 399. https://gcc.gnu.org/PR11693 19849 400. https://gcc.gnu.org/PR12224 19850 401. https://gcc.gnu.org/PR11087 19851 402. https://gcc.gnu.org/PR11319 19852 403. https://gcc.gnu.org/PR11949 19853 404. https://gcc.gnu.org/PR11662 19854 405. https://gcc.gnu.org/PR11965 19855 406. https://gcc.gnu.org/PR12301 19856 407. https://gcc.gnu.org/PR11717 19857 408. https://gcc.gnu.org/PR11313 19858 409. https://gcc.gnu.org/PR11712 19859 410. 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https://gcc.gnu.org/PR13475 19885 436. https://gcc.gnu.org/PR13797 19886 437. https://gcc.gnu.org/PR13824 19887 438. https://gcc.gnu.org/PR8776 19888 439. https://gcc.gnu.org/PR10339 19889 440. https://gcc.gnu.org/PR11350 19890 441. https://gcc.gnu.org/PR12826 19891 442. https://gcc.gnu.org/PR12500 19892 443. https://gcc.gnu.org/PR12941 19893 444. https://gcc.gnu.org/PR12953 19894 445. https://gcc.gnu.org/PR13041 19895 446. https://gcc.gnu.org/PR13507 19896 447. https://gcc.gnu.org/PR13382 19897 448. https://gcc.gnu.org/PR13394 19898 449. https://gcc.gnu.org/PR13400 19899 450. https://gcc.gnu.org/PR13521 19900 451. https://gcc.gnu.org/PR2094 19901 452. https://gcc.gnu.org/PR2294 19902 453. https://gcc.gnu.org/PR5050 19903 454. https://gcc.gnu.org/PR9371 19904 455. https://gcc.gnu.org/PR9546 19905 456. https://gcc.gnu.org/PR10081 19906 457. https://gcc.gnu.org/PR10093 19907 458. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#61 19908 459. https://gcc.gnu.org/PR10095 19909 460. https://gcc.gnu.org/PR11554 19910 461. https://gcc.gnu.org/PR12297 19911 462. https://gcc.gnu.org/PR12352 19912 463. https://gcc.gnu.org/PR12438 19913 464. https://gcc.gnu.org/PR12540 19914 465. https://gcc.gnu.org/PR12594 19915 466. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#60 19916 467. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#63 19917 468. https://gcc.gnu.org/PR12657 19918 469. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#292 19919 470. https://gcc.gnu.org/PR12696 19920 471. https://gcc.gnu.org/PR12815 19921 472. https://gcc.gnu.org/PR12862 19922 473. https://gcc.gnu.org/PR12926 19923 474. https://gcc.gnu.org/PR12967 19924 475. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html 19925 476. https://gcc.gnu.org/PR12971 19926 477. https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#328 19927 478. https://gcc.gnu.org/PR13007 19928 479. https://gcc.gnu.org/PR13009 19929 480. https://gcc.gnu.org/PR13057 19930 481. https://gcc.gnu.org/PR13070 19931 482. https://gcc.gnu.org/PR13081 19932 483. https://gcc.gnu.org/PR13239 19933 484. https://gcc.gnu.org/PR13262 19934 485. https://gcc.gnu.org/PR13290 19935 486. https://gcc.gnu.org/PR13323 19936 487. https://gcc.gnu.org/PR13369 19937 488. https://gcc.gnu.org/PR13371 19938 489. https://gcc.gnu.org/PR13445 19939 490. https://gcc.gnu.org/PR13461 19940 491. https://gcc.gnu.org/PR13462 19941 492. https://gcc.gnu.org/PR13478 19942 493. https://gcc.gnu.org/PR13544 19943 494. https://gcc.gnu.org/PR13650 19944 495. https://gcc.gnu.org/PR13683 19945 496. https://gcc.gnu.org/PR13688 19946 497. https://gcc.gnu.org/PR13774 19947 498. https://gcc.gnu.org/PR13884 19948 499. https://gcc.gnu.org/PR10746 19949 500. https://gcc.gnu.org/PR11433 19950 501. https://gcc.gnu.org/PR12633 19951 502. https://gcc.gnu.org/PR13037 19952 503. https://gcc.gnu.org/PR13213 19953 504. https://gcc.gnu.org/PR4490 19954 505. https://gcc.gnu.org/PR12292 19955 506. https://gcc.gnu.org/PR12441 19956 507. https://gcc.gnu.org/PR12943 19957 508. https://gcc.gnu.org/PR13608 19958 509. https://gcc.gnu.org/PR11598 19959 510. https://gcc.gnu.org/PR11793 19960 511. https://gcc.gnu.org/PR12467 19961 512. https://gcc.gnu.org/PR12537 19962 513. https://gcc.gnu.org/PR12496 19963 514. https://gcc.gnu.org/PR12865 19964 515. https://gcc.gnu.org/PR13354 19965 516. https://gcc.gnu.org/PR10467 19966 517. https://gcc.gnu.org/PR11226 19967 518. https://gcc.gnu.org/PR11227 19968 519. https://gcc.gnu.org/PR12644 19969 520. https://gcc.gnu.org/PR13149 19970 521. https://gcc.gnu.org/PR12654 19971 522. https://gcc.gnu.org/PR12965 19972 523. https://gcc.gnu.org/PR13031 19973 524. https://gcc.gnu.org/PR11634 19974 525. https://gcc.gnu.org/PR12158 19975 526. https://gcc.gnu.org/PR11992 19976 527. https://gcc.gnu.org/PR9365 19977 528. https://gcc.gnu.org/PR10392 19978 529. https://gcc.gnu.org/PR11322 19979 530. https://gcc.gnu.org/PR13069 19980 531. https://gcc.gnu.org/PR13302 19981 532. https://gcc.gnu.org/PR13585 19982 533. https://gcc.gnu.org/PR8916 19983 534. https://gcc.gnu.org/PR11576 19984 535. https://gcc.gnu.org/PR13122 19985 536. https://gcc.gnu.org/PR13256 19986 537. https://gcc.gnu.org/PR13373 19987 538. https://gcc.gnu.org/PR12561 19988 539. https://gcc.gnu.org/PR6243 19989 540. https://gcc.gnu.org/PR11397 19990 541. https://gcc.gnu.org/PR12505 19991 542. https://gcc.gnu.org/PR13150 19992 543. https://gcc.gnu.org/PR12666 19993 544. https://gcc.gnu.org/PR12969 19994 545. https://gcc.gnu.org/PR10819 19995 546. https://gcc.gnu.org/PR11612 19996 547. https://gcc.gnu.org/PR13211 19997 548. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.4 19998 549. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.5 19999 550. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.6 20000 551. https://gcc.gnu.org/onlinedocs/ 20001 552. mailto:gcc-help (a] gcc.gnu.org 20002 553. mailto:gcc (a] gcc.gnu.org 20003 554. https://gcc.gnu.org/lists.html 20004 555. https://www.fsf.org/ 20005 556. https://gcc.gnu.org/about.html 20006 ====================================================================== 20007 http://gcc.gnu.org/gcc-3.2/index.html 20008 20009 GCC 3.2 Release Series 20010 20011 (This release series is no longer supported.) 20012 20013 April 25, 2003 20014 20015 The [1]GNU project and the GCC developers are pleased to announce the 20016 release of GCC 3.2.3. 20017 20018 The purpose of the GCC 3.2 release series is to provide a stable 20019 platform for OS distributors to use building their next releases. A 20020 primary objective was to stabilize the C++ ABI; we believe that the 20021 interface to the compiler and the C++ standard library are now 20022 relatively stable. 20023 20024 Be aware that C++ code compiled by GCC 3.2.x will (in general) not 20025 interoperate with code compiled by GCC 3.1.1 or earlier. 20026 20027 Please refer to our [2]detailed list of news, caveats, and bug-fixes 20028 for further information. 20029 20030 Release History 20031 20032 GCC 3.2.3 20033 April 25, 2003 ([3]changes) 20034 20035 GCC 3.2.2 20036 February 5, 2003 ([4]changes) 20037 20038 GCC 3.2.1 20039 November 19, 2002 ([5]changes) 20040 20041 GCC 3.2 20042 August 14, 2002 ([6]changes) 20043 20044 References and Acknowledgements 20045 20046 GCC used to stand for the GNU C Compiler, but since the compiler 20047 supports several other languages aside from C, it now stands for the 20048 GNU Compiler Collection. 20049 20050 A list of [7]successful builds is updated as new information becomes 20051 available. 20052 20053 The GCC developers would like to thank the numerous people that have 20054 contributed new features, improvements, bug fixes, and other changes as 20055 well as test results to GCC. This [8]amazing group of volunteers is 20056 what makes GCC successful. 20057 20058 For additional information about GCC please refer to the [9]GCC project 20059 web site or contact the [10]GCC development mailing list. 20060 20061 To obtain GCC please use [11]our mirror sites, or our CVS server. 20062 20063 20064 For questions related to the use of GCC, please consult these web 20065 pages and the [12]GCC manuals. If that fails, the 20066 [13]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20067 web pages and the development of GCC are welcome on our developer 20068 list at [14]gcc (a] gcc.gnu.org. All of [15]our lists have public 20069 archives. 20070 20071 Copyright (C) [16]Free Software Foundation, Inc. Verbatim copying and 20072 distribution of this entire article is permitted in any medium, 20073 provided this notice is preserved. 20074 20075 These pages are [17]maintained by the GCC team. Last modified 20076 2022-10-26. 20077 20078 References 20079 20080 1. http://www.gnu.org/ 20081 2. http://gcc.gnu.org/gcc-3.2/changes.html 20082 3. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 20083 4. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.2 20084 5. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.1 20085 6. http://gcc.gnu.org/gcc-3.2/changes.html#3.2 20086 7. http://gcc.gnu.org/gcc-3.2/buildstat.html 20087 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 20088 9. http://gcc.gnu.org/index.html 20089 10. mailto:gcc (a] gcc.gnu.org 20090 11. http://gcc.gnu.org/mirrors.html 20091 12. https://gcc.gnu.org/onlinedocs/ 20092 13. mailto:gcc-help (a] gcc.gnu.org 20093 14. mailto:gcc (a] gcc.gnu.org 20094 15. https://gcc.gnu.org/lists.html 20095 16. https://www.fsf.org/ 20096 17. https://gcc.gnu.org/about.html 20097 ====================================================================== 20098 http://gcc.gnu.org/gcc-3.2/changes.html 20099 20100 GCC 3.2 Release Series 20101 Changes, New Features, and Fixes 20102 20103 The latest release in the 3.2 release series is [1]GCC 3.2.3. 20104 20105 Caveats and New Features 20106 20107 Caveats 20108 20109 * The C++ compiler does not correctly zero-initialize 20110 pointers-to-data members. You must explicitly initialize them. For 20111 example: int S::*m(0); will work, but depending on 20112 default-initialization to zero will not work. This bug cannot be 20113 fixed in GCC 3.2 without inducing unacceptable risks. It will be 20114 fixed in GCC 3.3. 20115 * This GCC release is based on the GCC 3.1 sourcebase, and thus has 20116 all the [2]changes in the GCC 3.1 series. In addition, GCC 3.2 has 20117 a number of C++ ABI fixes which make its C++ compiler generate 20118 binary code which is incompatible with the C++ compilers found in 20119 earlier GCC releases, including GCC 3.1 and GCC 3.1.1. 20120 20121 Frontend Enhancements 20122 20123 C/C++/Objective-C 20124 20125 * The method of constructing the list of directories to be searched 20126 for header files has been revised. If a directory named by a -I 20127 option is a standard system include directory, the option is 20128 ignored to ensure that the default search order for system 20129 directories and the special treatment of system header files are 20130 not defeated. 20131 * The C and Objective-C compilers no longer accept the "Naming Types" 20132 extension (typedef foo = bar); it was already unavailable in C++. 20133 Code which uses it will need to be changed to use the "typeof" 20134 extension instead: typedef typeof(bar) foo. (We have removed this 20135 extension without a period of deprecation because it has caused the 20136 compiler to crash since version 3.0 and no one noticed until very 20137 recently. Thus we conclude it is not in widespread use.) 20138 20139 C++ 20140 20141 * GCC 3.2 fixed serveral differences between the C++ ABI implemented 20142 in GCC and the multi-vendor standard, but more have been found 20143 since the release. 3.2.1 adds a new warning, -Wabi, to warn about 20144 code which is affected by these bugs. We will fix these bugs in 20145 some future release, once we are confident that all have been 20146 found; until then, it is our intention to make changes to the ABI 20147 only if they are necessary for correct compilation of C++, as 20148 opposed to conformance to the ABI documents. 20149 * For details on how to build an ABI compliant compiler for GNU/Linux 20150 systems, check the [3]common C++ ABI page. 20151 20152 New Targets and Target Specific Improvements 20153 20154 IA-32 20155 20156 * Fixed a number of bugs in SSE and MMX intrinsics. 20157 * Fixed common compiler crashes with SSE instruction set enabled 20158 (implied by -march=pentium3, pentium4, athlon-xp) 20159 * __m128 and __m128i is not 128bit aligned when used in structures. 20160 20161 x86-64 20162 20163 * A bug whereby the compiler could generate bad code for bzero has 20164 been fixed. 20165 * ABI fixes (implying ABI incompatibilities with previous version in 20166 some corner cases) 20167 * Fixed prefetch code generation 20168 __________________________________________________________________ 20169 20170 GCC 3.2.3 20171 20172 3.2.3 is a bug fix release only; there are no new features that were 20173 not present in GCC 3.2.2. 20174 20175 Bug Fixes 20176 20177 This section lists the problem reports (PRs) from GCC's bug tracking 20178 system that are known to be fixed in the 3.2.3 release. This list might 20179 not be complete (that is, it is possible that some PRs that have been 20180 fixed are not listed here), and some of the titles have been changed to 20181 make them more clear. 20182 20183 Internal Compiler Errors (multi-platform) 20184 20185 * [4]3782: (c++) -quiet -fstats produces a segmentation fault in 20186 cc1plus 20187 * [5]6440: (c++) template specializations cause ICE 20188 * [6]7050: (c++) ICE on: (i ? get_string() : throw) 20189 * [7]7741: ICE on conflicting types (make_decl_rtl in varasm.c) 20190 * [8]7982: (c++) ICE due to infinite recursion (using STL set) 20191 * [9]8068: exceedingly high (infinite) memory usage 20192 * [10]8178: ICE with __builtin_ffs 20193 * [11]8396: ICE in copy_to_mode_reg, in explow.c 20194 * [12]8674: (c++) ICE in cp_expr_size, in cp/cp-lang.c 20195 * [13]9768: ICE when optimizing inline code at -O2 20196 * [14]9798: (c++) Infinite recursion (segfault) in 20197 cp/decl.c:push_using_directive with recursive using directives 20198 * [15]9799: mismatching structure initializer with nested flexible 20199 array member: ICE 20200 * [16]9928: ICE on duplicate enum declaration 20201 * [17]10114: ICE in mem_loc_descriptor, in dwarf2out.c (affects 20202 sparc, alpha) 20203 * [18]10352: ICE in find_reloads_toplev 20204 * [19]10336: ICE with -Wunreachable-code 20205 20206 C/optimizer bugs: 20207 20208 * [20]8224: Incorrect joining of signed and unsigned division 20209 * [21]8613: -O2 produces wrong code with builtin strlen and 20210 postincrements 20211 * [22]8828: gcc reports some code is unreachable when it is not 20212 * [23]9226: GCSE breaking argument passing 20213 * [24]9853: miscompilation of non-constant structure initializer 20214 * [25]9797: C99-style struct initializers are miscompiled 20215 * [26]9967: Some standard C function calls should not be replaced 20216 when optimizing for size 20217 * [27]10116: ce2: invalid merge of join_bb in the context of switch 20218 statements 20219 * [28]10171: wrong code for inlined function 20220 * [29]10175: -Wunreachable-code doesn't work for single lines 20221 20222 C++ compiler and library: 20223 20224 * [30]8316: Confusing diagnostic for code that misuses conversion 20225 operators 20226 * [31]9169: filebuf output fails if codecvt<>::out returns noconv 20227 * [32]9420: incomplete type incorrectly reported 20228 * [33]9459: typeof in return type specification of template not 20229 supported 20230 * [34]9507: filebuf::open handles ios_base::ate incorrectly 20231 * [35]9538: Out-of-bounds memory access in streambuf::sputbackc 20232 * [36]9602: Total confusion about template/friend/virtual/abstract 20233 * [37]9993: destructor not called for local object created within and 20234 returned from infinite loop 20235 * [38]10167: ieee_1003.1-2001 locale specialisations on a glibc-2.3.2 20236 system 20237 20238 Java compiler and library: 20239 20240 * [39]9652: libgcj build fails on irix6.5.1[78] 20241 * [40]10144: gas on solaris complains about bad .stabs lines for 20242 java, native as unaffected 20243 20244 x86-specific (Intel/AMD): 20245 20246 * [41]8746: gcc miscompiles Linux kernel ppa driver on x86 20247 * [42]9888: -mcpu=k6 -Os produces out of range loop instructions 20248 * [43]9638: Cross-build for target i386-elf and i586-pc-linux-gnu 20249 failed 20250 * [44]9954: Cross-build for target i586-pc-linux-gnu (--with-newlib) 20251 failed 20252 20253 SPARC-specific: 20254 20255 * [45]7784: [Sparc] ICE in extract_insn, in recog.c 20256 * [46]7796: sparc extra failure with -m64 on execute/930921-1.c in 20257 unroll.c 20258 * [47]8281: ICE when compiling with -O2 -fPIC for Ultrasparc 20259 * [48]8366: [Sparc] C testsuite failure with -m64 -fpic -O in 20260 execute/loop-2d.c 20261 * [49]8726: gcc -O2 miscompiles Samba 2.2.7 on 32-bit sparc 20262 * [50]9414: Scheduling bug on Ultrasparc 20263 * [51]10067: GCC-3.2.2 outputs invalid asm on sparc64 20264 20265 m68k-specific: 20266 20267 * [52]7248: broken "inclusive or" code 20268 * [53]8343: m68k-elf/rtems ICE at instantiate_virtual_regs_1 20269 20270 PowerPC-specific: 20271 20272 * [54]9732: Wrong code with -O2 -fPIC 20273 * [55]10073: ICE: powerpc cannot split insn 20274 20275 Alpha-specific: 20276 20277 * [56]7702: optimization problem on a DEC alpha under OSF1 20278 * [57]9671: gcc.3.2.2 does not build on a HP Tru64 Unix v5.1B system 20279 20280 HP-specific: 20281 20282 * [58]8694: <string> breaks <ctype.h> on HP-UX 10.20 (DUP: 9275) 20283 * [59]9953: (ada) gcc 3.2.x can't build 3.3-branch ada on HP-UX 10 20284 (missing symbol) 20285 * [60]10271: Floating point args don't get reloaded across function 20286 calls with -O2 20287 20288 MIPS specific: 20289 20290 * [61]6362: mips-irix6 gcc-3.1 C testsuite failure with -mips4 in 20291 compile/920501-4.c 20292 20293 CRIS specific: 20294 20295 * [62]10377: gcc-3.2.2 creates bad assembler code for cris 20296 20297 Miscellaneous and minor bugs: 20298 20299 * [63]6955: collect2 says "core dumped" when there is no core 20300 __________________________________________________________________ 20301 20302 GCC 3.2.2 20303 20304 Beginning with 3.2.2, GCC's Makefile suite supports redirection of make 20305 install by means of the DESTDIR variable. Parts of the GCC tree have 20306 featured that support long before, but now it is available even from 20307 the top level. 20308 20309 Other than that, GCC 3.2.2 is a bug fix release only; there are no new 20310 features that were not present in GCC 3.2.1. 20311 20312 Bug Fixes 20313 20314 On the following i386-based systems GCC 3.2.1 broke the C ABI wrt. 20315 functions returning structures: Cygwin, FreeBSD (GCC 3.2.1 as shipped 20316 with FreeBSD 5.0 does not have this problem), Interix, a.out-based 20317 GNU/Linux and NetBSD, OpenBSD, and Darwin. GCC 3.2.2 reverts this ABI 20318 change, and thus restores ABI-compatibility with previous releases 20319 (except GCC 3.2.1) on these platforms. 20320 20321 This section lists the problem reports (PRs) from GCC's bug tracking 20322 system that are known to be fixed in the 3.2.2 release. This list might 20323 not be complete (that is, it is possible that some PRs that have been 20324 fixed are not listed here) and some of the titles have been changed to 20325 make them more clear. 20326 20327 Internal Compiler Errors (multi-platform) 20328 20329 * [64]5919: (c++) ICE when passing variable array to template 20330 function 20331 * [65]7129: (c++) ICE with min/max assignment operators (<?= and >?=) 20332 * [66]7507: ICE with -O2 when address of called function is a 20333 complicated expression 20334 * [67]7622: ICE with nested inline functions if function's address is 20335 taken 20336 * [68]7681: (fortran) ICE in compensate_edge, in reg-stack.c (also PR 20337 [69]9258) 20338 * [70]8031: (c++) ICE in code comparing typeids and casting from 20339 virtual base 20340 * [71]8275: ICE in simplify_subreg 20341 * [72]8332: (c++) builtin strlen/template interaction causes ICE 20342 * [73]8372: (c++) ICE on explicit call of destructor 20343 * [74]8439: (c, not c++) empty struct causes ICE 20344 * [75]8442: (c++) ICE with nested template classes 20345 * [76]8518: ICE when compiling mplayer ("extern inline" issue) 20346 * [77]8615: (c++) ICE with out-of-range character constant template 20347 argument 20348 * [78]8663: (c++) ICE in cp_expr_size, at cp-lang.c:307 20349 * [79]8799: (c++) ICE: error reporting routines re-entered 20350 * [80]9328: (c++) ICE with typeof(X) for overloaded X 20351 * [81]9465: (preprocessor) cpp -traditional ICE on null bytes 20352 20353 C++ (compiler and library) bugs 20354 20355 * [82]47: scoping in nested classes is broken 20356 * [83]6745: problems with iostream rdbuf() member function 20357 * [84]8214: conversion from const char* const to char* sometimes 20358 accepted illegally 20359 * [85]8493: builtin strlen and overload resolution (same bug as 20360 [86]8332) 20361 * [87]8503: strange behaviour of function types 20362 * [88]8727: compiler confused by inheritance from an anonymous struct 20363 * [89]7445: poor performance of std::locale::classic() in 20364 multi-threaded applications 20365 * [90]8230: mishandling of overflow in vector<T>::resize 20366 * [91]8399: sync_with_stdio(false) breaks unformatted input 20367 * [92]8662: illegal access of private member of unnamed class is 20368 accepted 20369 * [93]8707: "make distclean" fails in libstdc++-v3 directory 20370 * [94]8708: __USE_MALLOC doesn't work 20371 * [95]8790: Use of non-thread-safe strtok in src/localename.cc 20372 * [96]8887: Bug in date formats with --enable-clocale=generic 20373 * [97]9076: Call Frame Instructions are not handled correctly during 20374 unwind operation 20375 * [98]9151: std::setprecision limited to 16 digits when outputting a 20376 double to a stream 20377 * [99]9168: codecvt<char, char, mbstate_t> overwrites output buffers 20378 * [100]9269: libstdc++ headers: explicit specialization of function 20379 must precede its first use 20380 * [101]9322: return value of basic_streambuf<>::getloc affected by 20381 locale::global 20382 * [102]9433: segfault in runtime support for dynamic_cast 20383 20384 C and optimizer bugs 20385 20386 * [103]8032: GCC incorrectly initializes static structs that have 20387 flexible arrays 20388 * [104]8639: simple arithmetic expression broken 20389 * [105]8794: optimization improperly eliminates certain expressions 20390 * [106]8832: traditional "asm volatile" code is illegally optimized 20391 * [107]8988: loop optimizer bug: with -O2, code is generated that 20392 segfaults (found on i386, bug present for all platforms) 20393 * [108]9492: structure copy clobbers subsequent stores to structure 20394 20395 Objective-C bugs 20396 20397 * [109]9267: Objective-C parser won't build with newer bison versions 20398 (e.g. 1.875) 20399 20400 Ada bugs 20401 20402 * [110]8344: Ada build problem due to conflict between gcc/final.o, 20403 gcc/ada/final.o 20404 20405 Preprocessor bugs 20406 20407 * [111]8524: _Pragma within macros is improperly expanded 20408 * [112]8880: __WCHAR_TYPE__ macro incorrectly set to "long int" with 20409 -fshort-wchar 20410 20411 ARM-specific 20412 20413 * [113]9090: arm ICE with >= -O2; regression from gcc-2.95 20414 20415 x86-specific (Intel/AMD) 20416 20417 * [114]8588: ICE in extract_insn, at recog.c:NNNN (shift instruction) 20418 * [115]8599: loop unroll bug with -march=k6-3 20419 * [116]9506: ABI breakage in structure return (affects BSD and 20420 Cygwin, but not GNU/Linux) 20421 20422 FreeBSD 5.0 specific 20423 20424 * [117]9484: GCC 3.2.1 Bootstrap failure on FreeBSD 5.0 20425 20426 RTEMS-specific 20427 20428 * [118]9292: hppa1.1-rtems configurery problems 20429 * [119]9293: [m68k-elf/rtems] config/m68k/t-crtstuff bug 20430 * [120]9295: [mips-rtems] config/mips/rtems.h init/fini issue 20431 * [121]9296: gthr-rtems regression 20432 * [122]9316: powerpc-rtems: extending multilibs 20433 20434 HP-PA specific 20435 20436 * [123]9493: ICE with -O2 when building a simple function 20437 20438 Documentation 20439 20440 * [124]7341: hyperlink to gcov in GCC documentation doesn't work 20441 * [125]8947: Please add a warning about "-malign-double" in docs 20442 * [126]7448, [127]8882: typo cleanups 20443 __________________________________________________________________ 20444 20445 GCC 3.2.1 20446 20447 3.2.1 adds a new warning, -Wabi. This option warns when GNU C++ 20448 generates code that is known not to be binary-compatible with the 20449 vendor-neutral ia32/ia64 ABI. Please consult the GCC manual, included 20450 in the distribution, for details. 20451 20452 This release also removes an old GCC extension, "naming types", and the 20453 documentation now directs users to use a different GCC extension, 20454 __typeof__, instead. The feature had evidently been broken for a while. 20455 20456 Otherwise, 3.2.1 is a bug fix release only; other than bug fixes and 20457 the new warning there are no new features that were not present in GCC 20458 3.2. 20459 20460 In addition, the previous fix for [128]PR 7445 (poor performance of 20461 std::locale::classic() in multi-threaded applications) was reverted 20462 ("unfixed"), because the "fix" was not thread-safe. 20463 20464 Bug Fixes 20465 20466 This section lists the problem reports (PRs) from GCC's bug tracking 20467 system that are known to be fixed in the 3.2.1 release. This list might 20468 not be complete (that is, it is possible that some PRs that have been 20469 fixed are not listed here). As you can see, the number of bug fixes is 20470 quite large, so it is strongly recommended that users of earlier GCC 20471 3.x releases upgrade to GCC 3.2.1. 20472 20473 Internal Compiler Errors (multi-platform) 20474 20475 * [129]2521: (c++) ICE in build_ptrmemfunc, in cp/typeck.c 20476 * [130]5661: (c++) ICE instantiating template on array of unknown 20477 size (bad code) 20478 * [131]6419: (c++) ICE in make_decl_rtl for "longest" attribute on 20479 64-bit platforms 20480 * [132]6994: (c++) ICE in find_function_data 20481 * [133]7150: preprocessor: GCC -dM -E gives an ICE 20482 * [134]7160: ICE when optimizing branches without a return value 20483 * [135]7228: (c++) ICE when using member template and template 20484 function 20485 * [136]7266: (c++) ICE with -pedantic on missing typename 20486 * [137]7353: ICE from use of "Naming Types" extension, see above 20487 * [138]7411: ICE in instantiate_virtual_regs_1, in function.c 20488 * [139]7478: (c++) ICE on static_cast inside template 20489 * [140]7526: preprocessor core dump when _Pragma implies #pragma 20490 dependency 20491 * [141]7721: (c++) ICE on simple (but incorrect) template ([142]7803 20492 is a duplicate) 20493 * [143]7754: (c++) ICE on union with template parameter 20494 * [144]7788: (c++) redeclaring a definition as an incomplete class 20495 causes ICE 20496 * [145]8031: (c++) ICE in comptypes, in cp/typeck.c 20497 * [146]8055: preprocessor dies with SIG11 when building FreeBSD 20498 kernel 20499 * [147]8067: (c++) ICE due to mishandling of __FUNCTION__ and related 20500 variables 20501 * [148]8134: (c++) ICE in force_store_init_value on legal code 20502 * [149]8149: (c++) ICE on incomplete type 20503 * [150]8160: (c++) ICE in build_modify_expr, in cp/typeck.c: array 20504 initialization 20505 20506 C++ (compiler and library) bugs 20507 20508 * [151]5607: No pointer adjustment in covariant return types 20509 * [152]6579: Infinite loop with statement expressions in member 20510 initialization 20511 * [153]6803: Default copy constructor bug in GCC 3.1 20512 * [154]7176: g++ confused by friend and static member with same name 20513 * [155]7188: Segfault with template class and recursive (incorrect) 20514 initializer list 20515 * [156]7306: Regression: GCC 3.x fails to compile code with virtual 20516 inheritance if a method has a variable number of arguments 20517 * [157]7461: ctype<char>::classic_table() returns offset array on 20518 Cygwin 20519 * [158]7524: f(const float arg[3]) fails 20520 * [159]7584: Erroneous ambiguous base error on using declaration 20521 * [160]7676: Member template overloading problem 20522 * [161]7679: infinite loop when a right parenthesis is missing 20523 * [162]7811: default locale not taken from environment 20524 * [163]7961: compare( char *) implemented incorrectly in 20525 basic_string<> 20526 * [164]8071: basic_ostream::operator<<(streambuf*) loops forever if 20527 streambuf::underflow() leaves gptr() NULL (dups: [165]8127, 20528 [166]6745) 20529 * [167]8096: deque::at() throws std::range_error instead of 20530 std::out_of_range 20531 * [168]8127: cout << cin.rdbuf() infinite loop 20532 * [169]8218: Excessively large memory consumed for classes with large 20533 array members 20534 * [170]8287: GCC 3.2: Destructor called for non-constructed local 20535 object 20536 * [171]8347: empty vector range used in string construction causes 20537 core dump 20538 * [172]8348: fail() flag is set in istringstream when eof() flag is 20539 set 20540 * [173]8391: regression: infinite loop in cp/decl2.c(finish_file) 20541 20542 C and optimizer bugs 20543 20544 * [174]6627: -fno-align-functions doesn't seem to disable function 20545 alignment 20546 * [175]6631: life_analysis misoptimizes code to initialize fields of 20547 a structure 20548 * [176]7102: unsigned char division results in floating exception 20549 * [177]7120: Run once loop should *always* be unrolled 20550 (pessimization) 20551 * [178]7209: Bug involving array referencing and ?: operator 20552 * [179]7515: invalid inlining of global function with -O3 20553 * [180]7814: incorrect scheduling for glibc-2.2.92 strcpy test 20554 * [181]8467: bug in sibling call optimization 20555 20556 Preprocessor bugs 20557 20558 * [182]4890: incorrect line markers from the traditional preprocessor 20559 * [183]7357: -M option omits system headers files (making it the same 20560 as -MM) 20561 * [184]7358: Changes to Sun's make Dependencies 20562 * [185]7602: C++ header files found in CPLUS_INCLUDE_PATH treated as 20563 C headers 20564 * [186]7862: Interrupting GCC -MD removes .d file but not .o 20565 * [187]8190: Failed compilation deletes -MD dependency file 20566 * [188]8524: _Pragma within macro is improperly expanded 20567 20568 x86 specific (Intel/AMD) 20569 20570 * [189]5351: (i686-only) function pass-by-value structure copy 20571 corrupts stack ([190]7591 is a duplicate) 20572 * [191]6845, [192]7034, [193]7124, [194]7174: ICE's with 20573 -march=pentium3/pentium2/athlon (these are all the same underlying 20574 bug, in MMX register use) 20575 * [195]7134, [196]7375, [197]7390: ICE with -march=athlon (maybe same 20576 as above?) 20577 * [198]6890: xmmintrin.h, _MM_TRANSPOSE4_PS is broken 20578 * [199]6981: wrong code in 64-bit manipulation on x86 20579 * [200]7242: GCC -mcpu=pentium[23] doesn't define __tune_pentiumpro__ 20580 macro 20581 * [201]7396: ix86: cmpgt_ss, cmpge_ss, cmpngt_ss, and cmpnge_ss SSE 20582 intrinsics are broken 20583 * [202]7630: GCC 3.2 breaks on Mozilla 1.0's JS sources with 20584 -march=pentium4 20585 * [203]7693: Typo in i386 mmintrin.h header 20586 * [204]7723: ICE - Pentium3 sse - GCC 3.2 20587 * [205]7951: ICE on -march=pentium4 -O2 -mfpmath=sse 20588 * [206]8146: (i686 only) gcc 3.2 miscompiles gcc 2.95.3 20589 20590 PowerPC specific 20591 20592 * [207]5967: GCC bug when profiling nested functions on powerpc 20593 * [208]6984: wrong code generated with -O2, -O3, -Os for do-while 20594 loop on PowerPC 20595 * [209]7114: PowerPC: ICE building strcoll.op from glibc-2.2.5 20596 * [210]7130: miscompiled code for GCC-3.1 on 20597 powerpc-unknown-linux-gnu with -funroll-all-loops 20598 * [211]7133: PowerPC ICE: unrecognizable insn 20599 * [212]7380: ICE in extract_insn, at recog.c:2148 20600 * [213]8252: ICE on Altivec code with optimization turned on 20601 * [214]8451: Altivec ICE in GCC 3.2 20602 20603 HP/PA specific 20604 20605 * [215]7250: __ashrdi3 returns wrong value on 32 bit hppa 20606 20607 SPARC specific 20608 20609 * [216]6668: when using --disable-multilib, libgcc_s.so is installed 20610 in the wrong place on sparc-solaris 20611 * [217]7151: ICE when compiling for UltraSPARC 20612 * [218]7335: SPARC: ICE in verify_wide_reg (flow.c:557) with long 20613 double and -O1 20614 * [219]7842: [REGRESSION] SPARC code gen bug 20615 20616 ARM specific 20617 20618 * [220]7856: [arm] invalid offset in constant pool reference 20619 * [221]7967: optimization produces wrong code (ARM) 20620 20621 Alpha specific 20622 20623 * [222]7374: __builtin_fabsl broken on alpha 20624 20625 IBM s390 specific 20626 20627 * [223]7370: ICE in fixup_var_refs_1 on s390x 20628 * [224]7409: loop optimization bug on s390x-linux-gnu 20629 * [225]8232: s390x: ICE when using bcmp with int length argument 20630 20631 SCO specific 20632 20633 * [226]7623: SCO OpenServer build fails with machmode.def: undefined 20634 symbol: BITS_PER_UNIT 20635 20636 m68k/Coldfire specific 20637 20638 * [227]8314: crtbegin, crtend need to be multilib'ed for this 20639 platform 20640 20641 Documentation 20642 20643 * [228]761: Document some undocumented options 20644 * [229]5610: Fix documentation about invoking SSE instructions 20645 (-mfpmath=sse) 20646 * [230]7484: List -Wmissing-declarations as C-only option 20647 * [231]7531: -mcmodel not documented for x86-64 20648 * [232]8120: Update documentation of bad use of ## 20649 __________________________________________________________________ 20650 20651 GCC 3.2 20652 20653 3.2 is a small bug fix release, but there is a change to the 20654 application binary interface (ABI), hence the change to the second part 20655 of the version number. 20656 20657 The main purpose of the 3.2 release is to correct a couple of problems 20658 in the C++ ABI, with the intention of providing a stable interface 20659 going forward. Accordingly, 3.2 is only a small change to 3.1.1. 20660 20661 Bug Fixes 20662 20663 C++ 20664 20665 * [233]7320: g++ 3.2 relocation problem 20666 * [234]7470: vtable: virtual function pointers not in declaration 20667 order 20668 20669 libstdc++ 20670 20671 * [235]6410: Trouble with non-ASCII monetary symbols and wchar_t 20672 * [236]6503, [237]6642, [238]7186: Problems with comparing or 20673 subtracting various types of const and non-const iterators 20674 * [239]7216: ambiguity with basic_iostream::traits_type 20675 * [240]7220: problem with basic_istream::ignore(0,delimiter) 20676 * [241]7222: locale::operator==() doesn't work on std::locale("") 20677 * [242]7286: placement operator delete issue 20678 * [243]7442: cxxabi.h does not match the C++ ABI 20679 * [244]7445: poor performance of std::locale::classic() in 20680 multi-threaded applications 20681 20682 x86-64 specific 20683 20684 * [245]7291: off-by-one in generated inline bzero code for x86-64 20685 20686 20687 For questions related to the use of GCC, please consult these web 20688 pages and the [246]GCC manuals. If that fails, the 20689 [247]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20690 web pages and the development of GCC are welcome on our developer 20691 list at [248]gcc (a] gcc.gnu.org. All of [249]our lists have public 20692 archives. 20693 20694 Copyright (C) [250]Free Software Foundation, Inc. Verbatim copying and 20695 distribution of this entire article is permitted in any medium, 20696 provided this notice is preserved. 20697 20698 These pages are [251]maintained by the GCC team. Last modified 20699 2022-10-26. 20700 20701 References 20702 20703 1. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 20704 2. http://gcc.gnu.org/gcc-3.1/changes.html 20705 3. http://gcc.gnu.org/gcc-3.2/c++-abi.html 20706 4. https://gcc.gnu.org/PR3782 20707 5. https://gcc.gnu.org/PR6440 20708 6. https://gcc.gnu.org/PR7050 20709 7. https://gcc.gnu.org/PR7741 20710 8. https://gcc.gnu.org/PR7982 20711 9. https://gcc.gnu.org/PR8068 20712 10. https://gcc.gnu.org/PR8178 20713 11. https://gcc.gnu.org/PR8396 20714 12. https://gcc.gnu.org/PR8674 20715 13. https://gcc.gnu.org/PR9768 20716 14. https://gcc.gnu.org/PR9798 20717 15. https://gcc.gnu.org/PR9799 20718 16. https://gcc.gnu.org/PR9928 20719 17. https://gcc.gnu.org/PR10114 20720 18. https://gcc.gnu.org/PR10352 20721 19. https://gcc.gnu.org/PR10336 20722 20. https://gcc.gnu.org/PR8224 20723 21. https://gcc.gnu.org/PR8613 20724 22. https://gcc.gnu.org/PR8828 20725 23. https://gcc.gnu.org/PR9226 20726 24. https://gcc.gnu.org/PR9853 20727 25. 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https://gcc.gnu.org/PR6419 20834 132. https://gcc.gnu.org/PR6994 20835 133. https://gcc.gnu.org/PR7150 20836 134. https://gcc.gnu.org/PR7160 20837 135. https://gcc.gnu.org/PR7228 20838 136. https://gcc.gnu.org/PR7266 20839 137. https://gcc.gnu.org/PR7353 20840 138. https://gcc.gnu.org/PR7411 20841 139. https://gcc.gnu.org/PR7478 20842 140. https://gcc.gnu.org/PR7526 20843 141. https://gcc.gnu.org/PR7721 20844 142. https://gcc.gnu.org/PR7803 20845 143. https://gcc.gnu.org/PR7754 20846 144. https://gcc.gnu.org/PR7788 20847 145. https://gcc.gnu.org/PR8031 20848 146. https://gcc.gnu.org/PR8055 20849 147. https://gcc.gnu.org/PR8067 20850 148. https://gcc.gnu.org/PR8134 20851 149. https://gcc.gnu.org/PR8149 20852 150. https://gcc.gnu.org/PR8160 20853 151. https://gcc.gnu.org/PR5607 20854 152. https://gcc.gnu.org/PR6579 20855 153. https://gcc.gnu.org/PR6803 20856 154. https://gcc.gnu.org/PR7176 20857 155. https://gcc.gnu.org/PR7188 20858 156. https://gcc.gnu.org/PR7306 20859 157. https://gcc.gnu.org/PR7461 20860 158. https://gcc.gnu.org/PR7524 20861 159. https://gcc.gnu.org/PR7584 20862 160. https://gcc.gnu.org/PR7676 20863 161. https://gcc.gnu.org/PR7679 20864 162. https://gcc.gnu.org/PR7811 20865 163. https://gcc.gnu.org/PR7961 20866 164. https://gcc.gnu.org/PR8071 20867 165. https://gcc.gnu.org/PR8127 20868 166. https://gcc.gnu.org/PR6745 20869 167. https://gcc.gnu.org/PR8096 20870 168. https://gcc.gnu.org/PR8127 20871 169. https://gcc.gnu.org/PR8218 20872 170. https://gcc.gnu.org/PR8287 20873 171. https://gcc.gnu.org/PR8347 20874 172. https://gcc.gnu.org/PR8348 20875 173. https://gcc.gnu.org/PR8391 20876 174. https://gcc.gnu.org/PR6627 20877 175. https://gcc.gnu.org/PR6631 20878 176. https://gcc.gnu.org/PR7102 20879 177. https://gcc.gnu.org/PR7120 20880 178. https://gcc.gnu.org/PR7209 20881 179. https://gcc.gnu.org/PR7515 20882 180. https://gcc.gnu.org/PR7814 20883 181. https://gcc.gnu.org/PR8467 20884 182. https://gcc.gnu.org/PR4890 20885 183. https://gcc.gnu.org/PR7357 20886 184. https://gcc.gnu.org/PR7358 20887 185. https://gcc.gnu.org/PR7602 20888 186. https://gcc.gnu.org/PR7862 20889 187. https://gcc.gnu.org/PR8190 20890 188. https://gcc.gnu.org/PR8524 20891 189. https://gcc.gnu.org/PR5351 20892 190. https://gcc.gnu.org/PR7591 20893 191. https://gcc.gnu.org/PR6845 20894 192. https://gcc.gnu.org/PR7034 20895 193. https://gcc.gnu.org/PR7124 20896 194. https://gcc.gnu.org/PR7174 20897 195. https://gcc.gnu.org/PR7134 20898 196. https://gcc.gnu.org/PR7375 20899 197. https://gcc.gnu.org/PR7390 20900 198. https://gcc.gnu.org/PR6890 20901 199. https://gcc.gnu.org/PR6981 20902 200. https://gcc.gnu.org/PR7242 20903 201. https://gcc.gnu.org/PR7396 20904 202. https://gcc.gnu.org/PR7630 20905 203. https://gcc.gnu.org/PR7693 20906 204. https://gcc.gnu.org/PR7723 20907 205. https://gcc.gnu.org/PR7951 20908 206. https://gcc.gnu.org/PR8146 20909 207. https://gcc.gnu.org/PR5967 20910 208. https://gcc.gnu.org/PR6984 20911 209. https://gcc.gnu.org/PR7114 20912 210. https://gcc.gnu.org/PR7130 20913 211. https://gcc.gnu.org/PR7133 20914 212. https://gcc.gnu.org/PR7380 20915 213. https://gcc.gnu.org/PR8252 20916 214. https://gcc.gnu.org/PR8451 20917 215. https://gcc.gnu.org/PR7250 20918 216. https://gcc.gnu.org/PR6668 20919 217. https://gcc.gnu.org/PR7151 20920 218. https://gcc.gnu.org/PR7335 20921 219. https://gcc.gnu.org/PR7842 20922 220. https://gcc.gnu.org/PR7856 20923 221. https://gcc.gnu.org/PR7967 20924 222. https://gcc.gnu.org/PR7374 20925 223. https://gcc.gnu.org/PR7370 20926 224. https://gcc.gnu.org/PR7409 20927 225. https://gcc.gnu.org/PR8232 20928 226. https://gcc.gnu.org/PR7623 20929 227. https://gcc.gnu.org/PR8314 20930 228. https://gcc.gnu.org/PR761 20931 229. https://gcc.gnu.org/PR5610 20932 230. https://gcc.gnu.org/PR7484 20933 231. https://gcc.gnu.org/PR7531 20934 232. https://gcc.gnu.org/PR8120 20935 233. https://gcc.gnu.org/PR7320 20936 234. https://gcc.gnu.org/PR7470 20937 235. https://gcc.gnu.org/PR6410 20938 236. https://gcc.gnu.org/PR6503 20939 237. https://gcc.gnu.org/PR6642 20940 238. https://gcc.gnu.org/PR7186 20941 239. https://gcc.gnu.org/PR7216 20942 240. https://gcc.gnu.org/PR7220 20943 241. https://gcc.gnu.org/PR7222 20944 242. https://gcc.gnu.org/PR7286 20945 243. https://gcc.gnu.org/PR7442 20946 244. https://gcc.gnu.org/PR7445 20947 245. https://gcc.gnu.org/PR7291 20948 246. https://gcc.gnu.org/onlinedocs/ 20949 247. mailto:gcc-help (a] gcc.gnu.org 20950 248. mailto:gcc (a] gcc.gnu.org 20951 249. https://gcc.gnu.org/lists.html 20952 250. https://www.fsf.org/ 20953 251. https://gcc.gnu.org/about.html 20954 ====================================================================== 20955 http://gcc.gnu.org/gcc-3.1/index.html 20956 20957 GCC 3.1 20958 20959 (This release series is no longer supported.) 20960 20961 July 27, 2002 20962 20963 The [1]GNU project and the GCC developers are pleased to announce the 20964 release of GCC 3.1.1. 20965 20966 The links below still apply to GCC 3.1.1. 20967 20968 May 15, 2002 20969 20970 The [2]GNU project and the GCC developers are pleased to announce the 20971 release of GCC 3.1. 20972 20973 GCC used to stand for the GNU C Compiler, but since the compiler 20974 supports several other languages aside from C, it now stands for the 20975 GNU Compiler Collection. 20976 20977 A list of [3]successful builds is updated as new information becomes 20978 available. 20979 20980 The GCC developers would like to thank the numerous people that have 20981 contributed [4]new features, improvements, bug fixes, and other changes 20982 as well as test results to GCC. This [5]amazing group of volunteers is 20983 what makes GCC successful. 20984 20985 For additional information about GCC please refer to the [6]GCC project 20986 web site or contact the [7]GCC development mailing list. 20987 20988 To obtain GCC please use [8]our mirror sites, or our CVS server. 20989 __________________________________________________________________ 20990 20991 20992 For questions related to the use of GCC, please consult these web 20993 pages and the [9]GCC manuals. If that fails, the 20994 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20995 web pages and the development of GCC are welcome on our developer 20996 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 20997 archives. 20998 20999 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 21000 distribution of this entire article is permitted in any medium, 21001 provided this notice is preserved. 21002 21003 These pages are [14]maintained by the GCC team. Last modified 21004 2022-10-26. 21005 21006 References 21007 21008 1. http://www.gnu.org/ 21009 2. http://www.gnu.org/ 21010 3. http://gcc.gnu.org/gcc-3.1/buildstat.html 21011 4. http://gcc.gnu.org/gcc-3.1/changes.html 21012 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 21013 6. http://gcc.gnu.org/index.html 21014 7. mailto:gcc (a] gcc.gnu.org 21015 8. http://gcc.gnu.org/mirrors.html 21016 9. https://gcc.gnu.org/onlinedocs/ 21017 10. mailto:gcc-help (a] gcc.gnu.org 21018 11. mailto:gcc (a] gcc.gnu.org 21019 12. https://gcc.gnu.org/lists.html 21020 13. https://www.fsf.org/ 21021 14. https://gcc.gnu.org/about.html 21022 ====================================================================== 21023 http://gcc.gnu.org/gcc-3.1/changes.html 21024 21025 GCC 3.1 Release Series 21026 Changes, New Features, and Fixes 21027 21028 Additional changes in GCC 3.1.1 21029 21030 * A bug related to how structures and unions are returned has been 21031 fixed for powerpc-*-netbsd*. 21032 * An important bug in the implementation of -fprefetch-loop-arrays 21033 has been fixed. Previously the optimization prefetched random 21034 blocks of memory for most targets except for i386. 21035 * The Java compiler now compiles Java programs much faster and also 21036 works with parallel make. 21037 * Nested functions have been fixed for mips*-*-netbsd*. 21038 * Some missing floating point support routines have beed added for 21039 mips*-*-netbsd*. 21040 * This [1]message gives additional information about the bugs fixed 21041 in this release. 21042 21043 Caveats 21044 21045 * The -traditional C compiler option has been deprecated and will be 21046 removed in GCC 3.3. (It remains possible to preprocess non-C code 21047 with the traditional preprocessor.) 21048 * The default debugging format for most ELF platforms (including 21049 GNU/Linux and FreeBSD; notable exception is Solaris) has changed 21050 from stabs to DWARF2. This requires GDB 5.1.1 or later. 21051 21052 General Optimizer Improvements 21053 21054 * Jan Hubicka, SuSE Labs, together with Richard Henderson, Red Hat, 21055 and Andreas Jaeger, SuSE Labs, has contributed [2]infrastructure 21056 for profile driven optimizations. 21057 Options -fprofile-arcs and -fbranch-probabilities can now be used 21058 to improve speed of the generated code by profiling the actual 21059 program behaviour on typical runs. In the absence of profile info 21060 the compiler attempts to guess the profile statically. 21061 * [3]SPEC2000 and SPEC95 benchmark suites are now used daily to 21062 monitor performance of the generated code. 21063 According to the SPECInt2000 results on an AMD Athlon CPU, the code 21064 generated by GCC 3.1 is 6% faster on the average (8.2% faster with 21065 profile feedback) compared to GCC 3.0. The code produced by GCC 3.0 21066 is about 2.1% faster compared to 2.95.3. Tests were done using the 21067 -O2 -march=athlon command-line options. 21068 * Alexandre Oliva, of Red Hat, has generalized the tree inlining 21069 infrastructure developed by CodeSourcery, LLC for the C++ front 21070 end, so that it is now used in the C front end too. Inlining 21071 functions as trees exposes them earlier to the compiler, giving it 21072 more opportunities for optimization. 21073 * Support for data prefetching instructions has been added to the GCC 21074 back end and several targets. A new __builtin_prefetch intrinsic is 21075 available to explicitly insert prefetch instructions and 21076 experimental support for loop array prefetching has been added (see 21077 -fprefetch-loop-array documentation). 21078 * Support for emitting debugging information for macros has been 21079 added for DWARF2. It is activated using -g3. 21080 21081 New Languages and Language specific improvements 21082 21083 C/C++ 21084 21085 * A few more [4]ISO C99 features. 21086 * The preprocessor is 10-50% faster than the preprocessor in GCC 3.0. 21087 * The preprocessor's symbol table has been merged with the symbol 21088 table of the C, C++ and Objective-C front ends. 21089 * The preprocessor consumes less memory than the preprocessor in GCC 21090 3.0, often significantly so. On normal input files, it typically 21091 consumes less memory than pre-3.0 cccp-based GCC, too. 21092 21093 C++ 21094 21095 * -fhonor-std and -fno-honor-std have been removed. -fno-honor-std 21096 was a workaround to allow std compliant code to work with the 21097 non-std compliant libstdc++-v2. libstdc++-v3 is std compliant. 21098 * The C++ ABI has been fixed so that void (A::*)() const is mangled 21099 as "M1AKFvvE", rather than "MK1AFvvE" as before. This change only 21100 affects pointer to cv-qualified member function types. 21101 * The C++ ABI has been changed to correctly handle this code: 21102 struct A { 21103 void operator delete[] (void *, size_t); 21104 }; 21105 21106 struct B : public A { 21107 }; 21108 21109 new B[10]; 21110 21111 The amount of storage allocated for the array will be greater than 21112 it was in 3.0, in order to store the number of elements in the 21113 array, so that the correct size can be passed to operator delete[] 21114 when the array is deleted. Previously, the value passed to operator 21115 delete[] was unpredictable. 21116 This change will only affect code that declares a two-argument 21117 operator delete[] with a second parameter of type size_t in a base 21118 class, and does not override that definition in a derived class. 21119 * The C++ ABI has been changed so that: 21120 struct A { 21121 void operator delete[] (void *, size_t); 21122 void operator delete[] (void *); 21123 }; 21124 21125 does not cause unnecessary storage to be allocated when an array of 21126 A objects is allocated. 21127 This change will only affect code that declares both of these forms 21128 of operator delete[], and declared the two-argument form before the 21129 one-argument form. 21130 * The C++ ABI has been changed so that when a parameter is passed by 21131 value, any cleanup for that parameter is performed in the caller, 21132 as specified by the ia64 C++ ABI, rather than the called function 21133 as before. As a result, classes with a non-trivial destructor but a 21134 trivial copy constructor will be passed and returned by invisible 21135 reference, rather than by bitwise copy as before. 21136 * G++ now supports the "named return value optimization": for code 21137 like 21138 A f () { 21139 A a; 21140 ... 21141 return a; 21142 } 21143 21144 G++ will allocate a in the return value slot, so that the return 21145 becomes a no-op. For this to work, all return statements in the 21146 function must return the same variable. 21147 * Improvements to the C++ library are listed in [5]the libstdc++-v3 21148 FAQ. 21149 21150 Objective-C 21151 21152 * Annoying linker warnings (due to incorrect code being generated) 21153 have been fixed. 21154 * If a class method cannot be found, the compiler no longer issues a 21155 warning if a corresponding instance method exists in the root 21156 class. 21157 * Forward @protocol declarations have been fixed. 21158 * Loading of categories has been fixed in certain situations (GNU run 21159 time only). 21160 * The class lookup in the run-time library has been rewritten so that 21161 class method dispatch is more than twice as fast as it used to be 21162 (GNU run time only). 21163 21164 Java 21165 21166 * libgcj now includes RMI, java.lang.ref.*, javax.naming, and 21167 javax.transaction. 21168 * Property files and other system resources can be compiled into 21169 executables which use libgcj using the new gcj --resource feature. 21170 * libgcj has been ported to more platforms. In particular there is 21171 now a mostly-functional mingw32 (Windows) target port. 21172 * JNI and CNI invocation interfaces were implemented, so gcj-compiled 21173 Java code can now be called from a C/C++ application. 21174 * gcj can now use builtin functions for certain known methods, for 21175 instance Math.cos. 21176 * gcj can now automatically remove redundant array-store checks in 21177 some common cases. 21178 * The --no-store-checks optimization option was added. This can be 21179 used to omit runtime store checks for code which is known not to 21180 throw ArrayStoreException 21181 * The following third party interface standards were added to libgcj: 21182 org.w3c.dom and org.xml.sax. 21183 * java.security has been merged with GNU Classpath. The new package 21184 is now JDK 1.2 compliant, and much more complete. 21185 * A bytecode verifier was added to the libgcj interpreter. 21186 * java.lang.Character was rewritten to comply with the Unicode 3.0 21187 standard, and improve performance. 21188 * Partial support for many more locales was added to libgcj. 21189 * Socket timeouts have been implemented. 21190 * libgcj has been merged into a single shared library. There are no 21191 longer separate shared libraries for the garbage collector and 21192 zlib. 21193 * Several performance improvements were made to gcj and libgcj: 21194 + Hash synchronization (thin locks) 21195 + A special allocation path for finalizer-free objects 21196 + Thread-local allocation 21197 + Parallel GC, and other GC tweaks 21198 21199 Fortran 21200 21201 Fortran improvements are listed in [6]the Fortran documentation. 21202 21203 Ada 21204 21205 [7]AdaCore, has contributed its GNAT Ada 95 front end and associated 21206 tools. The GNAT compiler fully implements the Ada language as defined 21207 by the ISO/IEC 8652 standard. 21208 21209 Please note that the integration of the Ada front end is still work in 21210 progress. 21211 21212 New Targets and Target Specific Improvements 21213 21214 * Hans-Peter Nilsson has contributed a port to MMIX, the CPU 21215 architecture used in new editions of Donald E. Knuth's The Art of 21216 Computer Programming. 21217 * Axis Communications has contributed its port to the CRIS CPU 21218 architecture, used in the ETRAX system-on-a-chip series. 21219 * Alexandre Oliva, of Red Hat, has contributed a port to the SuperH 21220 SH5 64-bit RISC microprocessor architecture, extending the existing 21221 SH port. 21222 * UltraSPARC is fully supported in 64-bit mode. The option -m64 21223 enables it. 21224 * For compatibility with the Sun compiler #pragma redefine_extname 21225 has been implemented on Solaris. 21226 * The x86 back end has had some noticeable work done to it. 21227 + SuSE Labs developers Jan Hubicka, Bo Thorsen and Andreas 21228 Jaeger have contributed a port to the AMD x86-64 architecture. 21229 For more information on x86-64 see http://www.x86-64.org. 21230 + The compiler now supports MMX, 3DNow!, SSE, and SSE2 21231 instructions. Options -mmmx, -m3dnow, -msse, and -msse2 will 21232 enable the respective instruction sets. Intel C++ compatible 21233 MMX/3DNow!/SSE intrinsics are implemented. SSE2 intrinsics 21234 will be added in next major release. 21235 + Following those improvements, targets for Pentium MMX, K6-2, 21236 K6-3, Pentium III, Pentium 4, and Athlon 4 Mobile/XP/MP were 21237 added. Refer to the documentation on -march= and -mcpu= 21238 options for details. 21239 + For those targets that support it, -mfpmath=sse will cause the 21240 compiler to generate SSE/SSE2 instructions for floating point 21241 math instead of x87 instructions. Usually, this will lead to 21242 quicker code -- especially on the Pentium 4. Note that only 21243 scalar floating point instructions are used and GCC does not 21244 exploit SIMD features yet. 21245 + Prefetch support has been added to the Pentium III, Pentium 4, 21246 K6-2, K6-3, and Athlon series. 21247 + Code generated for floating point to integer conversions has 21248 been improved leading to better performance of many 3D 21249 applications. 21250 * The PowerPC back end has added 64-bit PowerPC GNU/Linux support. 21251 * C++ support for AIX has been improved. 21252 * Aldy Hernandez, of Red Hat, Inc, has contributed extensions to the 21253 PowerPC port supporting the AltiVec programming model (SIMD). The 21254 support, though presently useful, is experimental and is expected 21255 to stabilize for 3.2. The support is written to conform to 21256 Motorola's AltiVec specs. See -maltivec. 21257 21258 Obsolete Systems 21259 21260 Support for a number of older systems has been declared obsolete in GCC 21261 3.1. Unless there is activity to revive them, the next release of GCC 21262 will have their sources permanently removed. 21263 21264 All configurations of the following processor architectures have been 21265 declared obsolete: 21266 * MIL-STD-1750A, 1750a-*-* 21267 * AMD A29k, a29k-*-* 21268 * Convex, c*-convex-* 21269 * Clipper, clipper-*-* 21270 * Elxsi, elxsi-*-* 21271 * Intel i860, i860-*-* 21272 * Sun picoJava, pj-*-* and pjl-*-* 21273 * Western Electric 32000, we32k-*-* 21274 21275 Most configurations of the following processor architectures have been 21276 declared obsolete, but we are preserving a few systems which may have 21277 active developers. It is unlikely that the remaining systems will 21278 survive much longer unless we see definite signs of port activity. 21279 * Motorola 88000 except 21280 + Generic a.out, m88k-*-aout* 21281 + Generic SVR4, m88k-*-sysv4 21282 + OpenBSD, m88k-*-openbsd* 21283 * NS32k except 21284 + NetBSD, ns32k-*-netbsd* 21285 + OpenBSD, ns32k-*-openbsd*. 21286 * ROMP except 21287 + OpenBSD, romp-*-openbsd*. 21288 21289 Finally, only some configurations of these processor architectures are 21290 being obsoleted. 21291 * Alpha: 21292 + OSF/1, alpha*-*-osf[123]*. (Digital Unix and Tru64 Unix, aka 21293 alpha*-*-osf[45], are still supported.) 21294 * ARM: 21295 + RISCiX, arm-*-riscix*. 21296 * i386: 21297 + 386BSD, i?86-*-bsd* 21298 + Chorus, i?86-*-chorusos* 21299 + DG/UX, i?86-*-dgux* 21300 + FreeBSD 1.x, i?86-*-freebsd1.* 21301 + IBM AIX, i?86-*-aix* 21302 + ISC UNIX, i?86-*-isc* 21303 + GNU/Linux with pre-BFD linker, i?86-*-linux*oldld* 21304 + NEXTstep, i?86-next-* 21305 + OSF UNIX, i?86-*-osf1* and i?86-*-osfrose* 21306 + RTEMS/coff, i?86-*-rtemscoff* 21307 + RTEMS/go32, i?86-go32-rtems* 21308 + Sequent/BSD, i?86-sequent-bsd* 21309 + Sequent/ptx before version 3, i?86-sequent-ptx[12]* and 21310 i?86-sequent-sysv3* 21311 + SunOS, i?86-*-sunos* 21312 * Motorola 68000: 21313 + Altos, m68[k0]*-altos-* 21314 + Apollo, m68[k0]*-apollo-* 21315 + Apple A/UX, m68[k0]*-apple-* 21316 + Bull, m68[k0]*-bull-* 21317 + Convergent, m68[k0]*-convergent-* 21318 + Generic SVR3, m68[k0]*-*-sysv3* 21319 + ISI, m68[k0]*-isi-* 21320 + LynxOS, m68[k0]*-*-lynxos* 21321 + NEXT, m68[k0]*-next-* 21322 + RTEMS/coff, m68[k0]*-*-rtemscoff* 21323 + Sony, m68[k0]*-sony-* 21324 * MIPS: 21325 + DEC Ultrix, mips-*-ultrix* and mips-dec-* 21326 + Generic BSD, mips-*-bsd* 21327 + Generic System V, mips-*-sysv* 21328 + IRIX before version 5, mips-sgi-irix[1234]* 21329 + RiscOS, mips-*-riscos* 21330 + Sony, mips-sony-* 21331 + Tandem, mips-tandem-* 21332 * SPARC: 21333 + RTEMS/a.out, sparc-*-rtemsaout*. 21334 21335 Documentation improvements 21336 21337 * The old manual ("Using and Porting the GNU Compiler Collection") 21338 has been replaced by a users manual ("Using the GNU Compiler 21339 Collection") and a separate internals reference manual ("GNU 21340 Compiler Collection Internals"). 21341 * More complete and much improved documentation about GCC's internal 21342 representation used by the C and C++ front ends. 21343 * Many cleanups and improvements in general. 21344 21345 21346 For questions related to the use of GCC, please consult these web 21347 pages and the [8]GCC manuals. If that fails, the 21348 [9]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 21349 web pages and the development of GCC are welcome on our developer 21350 list at [10]gcc (a] gcc.gnu.org. All of [11]our lists have public 21351 archives. 21352 21353 Copyright (C) [12]Free Software Foundation, Inc. Verbatim copying and 21354 distribution of this entire article is permitted in any medium, 21355 provided this notice is preserved. 21356 21357 These pages are [13]maintained by the GCC team. Last modified 21358 2022-10-26. 21359 21360 References 21361 21362 1. https://gcc.gnu.org/ml/gcc/2002-07/msg01208.html 21363 2. http://gcc.gnu.org/news/profiledriven.html 21364 3. http://gcc.gnu.org/benchmarks/ 21365 4. http://gcc.gnu.org/c99status.html 21366 5. https://gcc.gnu.org/onlinedocs/libstdc++/faq.html 21367 6. https://gcc.gnu.org/onlinedocs/gcc-3.1.1/g77/News.html 21368 7. https://www.adacore.com/ 21369 8. https://gcc.gnu.org/onlinedocs/ 21370 9. mailto:gcc-help (a] gcc.gnu.org 21371 10. mailto:gcc (a] gcc.gnu.org 21372 11. https://gcc.gnu.org/lists.html 21373 12. https://www.fsf.org/ 21374 13. https://gcc.gnu.org/about.html 21375 ====================================================================== 21376 http://gcc.gnu.org/gcc-3.0/index.html 21377 21378 GCC 3.0.4 21379 21380 (This release series is no longer supported.) 21381 21382 February 20, 2002 21383 21384 The [1]GNU project and the GCC developers are pleased to announce the 21385 release of GCC 3.0.4, which is a bug-fix release for the GCC 3.0 21386 series. 21387 21388 GCC used to stand for the GNU C Compiler, but since the compiler 21389 supports several other languages aside from C, it now stands for the 21390 GNU Compiler Collection. 21391 21392 GCC 3.0.x has several new optimizations, new targets, new languages and 21393 many other new features, relative to GCC 2.95.x. See the [2]new 21394 features page for a more complete list. 21395 21396 A list of [3]successful builds is updated as new information becomes 21397 available. 21398 21399 The GCC developers would like to thank the numerous people that have 21400 contributed new features, test results, bug fixes, etc to GCC. This 21401 [4]amazing group of volunteers is what makes GCC successful. 21402 21403 And finally, we can't in good conscience fail to mention some 21404 [5]caveats to using GCC 3.0.x. 21405 21406 For additional information about GCC please refer to the [6]GCC project 21407 web site or contact the [7]GCC development mailing list. 21408 21409 To obtain GCC please use [8]our mirror sites, or our CVS server. 21410 __________________________________________________________________ 21411 21412 Previous 3.0.x Releases 21413 21414 December 20, 2001: GCC 3.0.3 has been released. 21415 October 25, 2001: GCC 3.0.2 has been released. 21416 August 20, 2001: GCC 3.0.1 has been released. 21417 June 18, 2001: GCC 3.0 has been released. 21418 21419 21420 For questions related to the use of GCC, please consult these web 21421 pages and the [9]GCC manuals. If that fails, the 21422 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 21423 web pages and the development of GCC are welcome on our developer 21424 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 21425 archives. 21426 21427 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 21428 distribution of this entire article is permitted in any medium, 21429 provided this notice is preserved. 21430 21431 These pages are [14]maintained by the GCC team. Last modified 21432 2022-10-26. 21433 21434 References 21435 21436 1. http://www.gnu.org/ 21437 2. http://gcc.gnu.org/gcc-3.0/features.html 21438 3. http://gcc.gnu.org/gcc-3.0/buildstat.html 21439 4. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 21440 5. http://gcc.gnu.org/gcc-3.0/caveats.html 21441 6. http://gcc.gnu.org/index.html 21442 7. mailto:gcc (a] gcc.gnu.org 21443 8. http://gcc.gnu.org/mirrors.html 21444 9. https://gcc.gnu.org/onlinedocs/ 21445 10. mailto:gcc-help (a] gcc.gnu.org 21446 11. mailto:gcc (a] gcc.gnu.org 21447 12. https://gcc.gnu.org/lists.html 21448 13. https://www.fsf.org/ 21449 14. https://gcc.gnu.org/about.html 21450 ====================================================================== 21451 http://gcc.gnu.org/gcc-3.0/features.html 21452 21453 GCC 3.0 New Features 21454 21455 Additional changes in GCC 3.0.4 21456 21457 * GCC 3.0 now supports newer versions of the [1]NetBSD operating 21458 system, which use the ELF object file format, on x86 processors. 21459 * Correct debugging information is generated from functions that have 21460 lines from multiple files (e.g. yacc output). 21461 * A fix for whitespace handling in the -traditional preprocessor, 21462 which can affect Fortran. 21463 * Fixes to the exception handling runtime. 21464 * More fixes for bad code generation in C++. 21465 * A fix for shared library generation under AIX 4.3. 21466 * Documentation updates. 21467 * Port of GCC to Tensilica's Xtensa processor contributed. 21468 * A fix for compiling the PPC Linux kernel (FAT fs wouldn't link). 21469 21470 Additional changes in GCC 3.0.3 21471 21472 * A fix to correct an accidental change to the PowerPC ABI. 21473 * Fixes for bad code generation on a variety of architectures. 21474 * Improvements to the debugging information generated for C++ 21475 classes. 21476 * Fixes for bad code generation in C++. 21477 * A fix to avoid crashes in the C++ demangler. 21478 * A fix to the C++ standard library to avoid buffer overflows. 21479 * Miscellaneous improvements for a variety of architectures. 21480 21481 Additional changes in GCC 3.0.2 21482 21483 * Fixes for bad code generation during loop unrolling. 21484 * Fixes for bad code generation by the sibling call optimization. 21485 * Minor improvements to x86 code generation. 21486 * Implementation of function descriptors in C++ vtables for IA64. 21487 * Numerous minor bug-fixes. 21488 21489 Additional changes in GCC 3.0.1 21490 21491 * C++ fixes for incorrect code-generation. 21492 * Improved cross-compiling support for the C++ standard library. 21493 * Fixes for some embedded targets that worked in GCC 2.95.3, but not 21494 in GCC 3.0. 21495 * Fixes for various exception-handling bugs. 21496 * A port to the S/390 architecture. 21497 21498 General Optimizer Improvements 21499 21500 * [2]Basic block reordering pass. 21501 * New if-conversion pass with support for conditional (predicated) 21502 execution. 21503 * New tail call and sibling call elimination optimizations. 21504 * New register renaming pass. 21505 * New (experimental) [3]static single assignment (SSA) representation 21506 support. 21507 * New dead-code elimination pass implemented using the SSA 21508 representation. 21509 * [4]Global null pointer test elimination. 21510 * [5]Global code hoisting/unification. 21511 * More builtins and optimizations for stdio.h, string.h and old BSD 21512 functions, as well as for ISO C99 functions. 21513 * New builtin __builtin_expect for giving hints to the branch 21514 predictor. 21515 21516 New Languages and Language specific improvements 21517 21518 * The GNU Compiler for the Java(TM) language (GCJ) is now integrated 21519 and supported, including the run-time library containing most 21520 common non-GUI Java classes, a bytecode interpreter, and the Boehm 21521 conservative garbage collector. Many bugs have been fixed. GCJ can 21522 compile Java source or Java bytecodes to either native code or Java 21523 class files, and supports native methods written in either the 21524 standard JNI or the more efficient and convenient CNI. 21525 * Here is a [6]partial list of C++ improvements, both new features 21526 and those no longer supported. 21527 * New C++ ABI. On the IA-64 platform GCC is capable of 21528 inter-operating with other IA-64 compilers. 21529 * The new ABI also significantly reduces the size of symbol and debug 21530 information. 21531 * New C++ support library and many C++ bug fixes, vastly improving 21532 our conformance to the ISO C++ standard. 21533 * New [7]inliner for C++. 21534 * Rewritten C preprocessor, integrated into the C, C++ and Objective 21535 C compilers, with very many improvements including ISO C99 support 21536 and [8]improvements to dependency generation. 21537 * Support for more [9]ISO C99 features. 21538 * Many improvements to support for checking calls to format functions 21539 such as printf and scanf, including support for ISO C99 format 21540 features, extensions from the Single Unix Specification and GNU 21541 libc 2.2, checking of strfmon formats and features to assist in 21542 auditing for format string security bugs. 21543 * New warnings for C code that may have undefined semantics because 21544 of violations of sequence point rules in the C standard (such as a 21545 = a++;, a[n] = b[n++]; and a[i++] = i;), included in -Wall. 21546 * Additional warning option -Wfloat-equal. 21547 * Improvements to -Wtraditional. 21548 * Fortran improvements are listed in [10]the Fortran documentation. 21549 21550 New Targets and Target Specific Improvements 21551 21552 * New x86 back end, generating much improved code. 21553 * Support for a generic i386-elf target contributed. 21554 * New option to emit x86 assembly code using Intel style syntax 21555 (-mintel-syntax). 21556 * HPUX 11 support contributed. 21557 * Improved PowerPC code generation, including scheduled prologue and 21558 epilogue. 21559 * Port of GCC to Intel's IA-64 processor contributed. 21560 * Port of GCC to Motorola's MCore 210 and 340 contributed. 21561 * New unified back-end for Arm, Thumb and StrongArm contributed. 21562 * Port of GCC to Intel's XScale processor contributed. 21563 * Port of GCC to Atmel's AVR microcontrollers contributed. 21564 * Port of GCC to Mitsubishi's D30V processor contributed. 21565 * Port of GCC to Matsushita's AM33 processor (a member of the MN10300 21566 processor family) contributed. 21567 * Port of GCC to Fujitsu's FR30 processor contributed. 21568 * Port of GCC to Motorola's 68HC11 and 68HC12 processors contributed. 21569 * Port of GCC to Sun's picoJava processor core contributed. 21570 21571 Documentation improvements 21572 21573 * Substantially rewritten and improved C preprocessor manual. 21574 * Many improvements to other documentation. 21575 * Manpages for gcc, cpp and gcov are now generated automatically from 21576 the master Texinfo manual, eliminating the problem of manpages 21577 being out of date. (The generated manpages are only extracts from 21578 the full manual, which is provided in Texinfo form, from which 21579 info, HTML, other formats and a printed manual can be generated.) 21580 * Generated info files are included in the release tarballs alongside 21581 their Texinfo sources, avoiding problems on some platforms with 21582 building makeinfo as part of the GCC distribution. 21583 21584 Other significant improvements 21585 21586 * Garbage collection used internally by the compiler for most memory 21587 allocation instead of obstacks. 21588 * Lengauer and Tarjan algorithm used for computing dominators in the 21589 CFG. This algorithm can be significantly faster and more space 21590 efficient than our older algorithm. 21591 * gccbug script provided to assist in submitting bug reports to our 21592 bug tracking system. (Bug reports previously submitted directly to 21593 our mailing lists, for which you received no bug tracking number, 21594 should be submitted again using gccbug if you can reproduce the 21595 problem with GCC 3.0.) 21596 * The internal libgcc library is [11]built as a shared library on 21597 systems that support it. 21598 * Extensive testsuite included with GCC, with many new tests. In 21599 addition to tests for GCC bugs that have been fixed, many tests 21600 have been added for language features, compiler warnings and 21601 builtin functions. 21602 * Additional language-independent warning options -Wpacked, -Wpadded, 21603 -Wunreachable-code and -Wdisabled-optimization. 21604 * Target-independent options -falign-functions, -falign-loops and 21605 -falign-jumps. 21606 21607 Plus a great many bug fixes and almost all the [12]features found in 21608 GCC 2.95. 21609 21610 21611 For questions related to the use of GCC, please consult these web 21612 pages and the [13]GCC manuals. If that fails, the 21613 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 21614 web pages and the development of GCC are welcome on our developer 21615 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 21616 archives. 21617 21618 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 21619 distribution of this entire article is permitted in any medium, 21620 provided this notice is preserved. 21621 21622 These pages are [18]maintained by the GCC team. Last modified 21623 2022-10-26. 21624 21625 References 21626 21627 1. http://www.netbsd.org/ 21628 2. http://gcc.gnu.org/news/reorder.html 21629 3. http://gcc.gnu.org/news/ssa.html 21630 4. http://gcc.gnu.org/news/null.html 21631 5. http://gcc.gnu.org/news/unify.html 21632 6. http://gcc.gnu.org/gcc-3.0/c++features.html 21633 7. http://gcc.gnu.org/news/inlining.html 21634 8. http://gcc.gnu.org/news/dependencies.html 21635 9. http://gcc.gnu.org/c99status.html 21636 10. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 21637 11. http://gcc.gnu.org/gcc-3.0/libgcc.html 21638 12. http://gcc.gnu.org/gcc-2.95/features.html 21639 13. https://gcc.gnu.org/onlinedocs/ 21640 14. mailto:gcc-help (a] gcc.gnu.org 21641 15. mailto:gcc (a] gcc.gnu.org 21642 16. https://gcc.gnu.org/lists.html 21643 17. https://www.fsf.org/ 21644 18. https://gcc.gnu.org/about.html 21645 ====================================================================== 21646 http://gcc.gnu.org/gcc-3.0/caveats.html 21647 21648 GCC 3.0 Caveats 21649 21650 * -fstrict-aliasing is now part of -O2 and higher optimization 21651 levels. This allows the compiler to assume the strictest aliasing 21652 rules applicable to the language being compiled. For C and C++, 21653 this activates optimizations based on the type of expressions. This 21654 optimization may thus break old, non-compliant code. 21655 * Enumerations are now properly promoted to int in function 21656 parameters and function returns. Normally this change is not 21657 visible, but when using -fshort-enums this is an ABI change. 21658 * The undocumented extension that allowed C programs to have a label 21659 at the end of a compound statement has been deprecated and may be 21660 removed in a future version. Programs that now generate a warning 21661 about this may be fixed by adding a null statement (a single 21662 semicolon) after the label. 21663 * The poorly documented extension that allowed string constants in C, 21664 C++ and Objective C to contain unescaped newlines has been 21665 deprecated and may be removed in a future version. Programs using 21666 this extension may be fixed in several ways: the bare newline may 21667 be replaced by \n, or preceded by \n\, or string concatenation may 21668 be used with the bare newline preceded by \n" and " placed at the 21669 start of the next line. 21670 * The Chill compiler is not included in GCC 3.0, because of the lack 21671 of a volunteer to convert it to use garbage collection. 21672 * Certain non-standard iostream methods from earlier versions of 21673 libstdc++ are not included in libstdc++ v3, i.e. filebuf::attach, 21674 ostream::form, and istream::gets. 21675 * The new C++ ABI is not yet fully supported by current (as of 21676 2001-07-01) releases and development versions of GDB, or any 21677 earlier versions. There is a problem setting breakpoints by line 21678 number, and other related issues that have been fixed in GCC 3.0 21679 but not yet handled in GDB: 21680 [1]https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 21681 21682 21683 For questions related to the use of GCC, please consult these web 21684 pages and the [2]GCC manuals. If that fails, the 21685 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 21686 web pages and the development of GCC are welcome on our developer 21687 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 21688 21689 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 21690 distribution of this entire article is permitted in any medium, 21691 provided this notice is preserved. 21692 21693 These pages are [7]maintained by the GCC team. Last modified 21694 2022-10-26. 21695 21696 References 21697 21698 1. https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 21699 2. https://gcc.gnu.org/onlinedocs/ 21700 3. mailto:gcc-help (a] gcc.gnu.org 21701 4. mailto:gcc (a] gcc.gnu.org 21702 5. https://gcc.gnu.org/lists.html 21703 6. https://www.fsf.org/ 21704 7. https://gcc.gnu.org/about.html 21705 ====================================================================== 21706 http://gcc.gnu.org/gcc-2.95/index.html 21707 21708 GCC 2.95 21709 21710 (This release series is no longer supported.) 21711 21712 March 16, 2001: The GNU project and the GCC developers are pleased to 21713 announce the release of GCC version 2.95.3. 21714 21715 Release History 21716 21717 GCC 2.95.3 21718 March 16, 2001 21719 21720 GCC 2.95.2 21721 October 27, 1999 21722 21723 GCC 2.95.1 21724 August 19, 1999 21725 21726 GCC 2.95 21727 July 31, 1999. This is the first release of GCC since the April 21728 1999 GCC/EGCS reunification and includes nearly a year's worth 21729 of new development and bugfixes. 21730 21731 References and Acknowledgements 21732 21733 GCC used to stand for the GNU C Compiler, but since the compiler 21734 supports several other languages aside from C, it now stands for the 21735 GNU Compiler Collection. 21736 21737 The whole suite has been extensively [1]regression tested and 21738 [2]package tested. It should be reliable and suitable for widespread 21739 use. 21740 21741 The compiler has several new optimizations, new targets, new languages 21742 and other new features. See the [3]new features page for a more 21743 complete list of new features found in the GCC 2.95 releases. 21744 21745 The sources include installation instructions in both HTML and 21746 plaintext forms in the install directory in the distribution. However, 21747 the most up to date installation instructions and [4]build/test status 21748 are on the web pages. We will update those pages as new information 21749 becomes available. 21750 21751 The GCC developers would like to thank the numerous people that have 21752 contributed new features, test results, bugfixes, etc to GCC. This 21753 [5]amazing group of volunteers is what makes GCC successful. 21754 21755 And finally, we can't in good conscience fail to mention some 21756 [6]caveats to using GCC 2.95. 21757 21758 Download GCC 2.95 from one of our many [7]mirror sites. 21759 21760 For additional information about GCC please see the [8]GCC project web 21761 server or contact the [9]GCC development mailing list. 21762 21763 21764 For questions related to the use of GCC, please consult these web 21765 pages and the [10]GCC manuals. If that fails, the 21766 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 21767 web pages and the development of GCC are welcome on our developer 21768 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 21769 archives. 21770 21771 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 21772 distribution of this entire article is permitted in any medium, 21773 provided this notice is preserved. 21774 21775 These pages are [15]maintained by the GCC team. Last modified 21776 2022-10-26. 21777 21778 References 21779 21780 1. http://gcc.gnu.org/gcc-2.95/regress.html 21781 2. http://gcc.gnu.org/gcc-2.95/othertest.html 21782 3. http://gcc.gnu.org/gcc-2.95/features.html 21783 4. http://gcc.gnu.org/gcc-2.95/buildstat.html 21784 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 21785 6. http://gcc.gnu.org/gcc-2.95/caveats.html 21786 7. http://gcc.gnu.org/mirrors.html 21787 8. http://gcc.gnu.org/index.html 21788 9. mailto:gcc (a] gcc.gnu.org 21789 10. https://gcc.gnu.org/onlinedocs/ 21790 11. mailto:gcc-help (a] gcc.gnu.org 21791 12. mailto:gcc (a] gcc.gnu.org 21792 13. https://gcc.gnu.org/lists.html 21793 14. https://www.fsf.org/ 21794 15. https://gcc.gnu.org/about.html 21795 ====================================================================== 21796 http://gcc.gnu.org/gcc-2.95/features.html 21797 21798 GCC 2.95 New Features 21799 21800 * General Optimizer Improvements: 21801 + [1]Localized register spilling to improve speed and code 21802 density especially on small register class machines. 21803 + [2]Global CSE using lazy code motion algorithms. 21804 + [3]Improved global constant/copy propagation. 21805 + [4]Improved control flow graph analysis and manipulation. 21806 + [5]Local dead store elimination. 21807 + [6]Memory Load hoisting/store sinking in loops. 21808 + [7]Type based alias analysis is enabled by default. Note this 21809 feature will expose bugs in the Linux kernel. Please refer to 21810 the FAQ (as shipped with GCC 2.95) for additional information 21811 on this issue. 21812 + Major revamp of GIV detection, combination and simplification 21813 to improve loop performance. 21814 + Major improvements to register allocation and reloading. 21815 * New Languages and Language specific improvements 21816 + [8]Many C++ improvements. 21817 + [9]Many Fortran improvements. 21818 + [10]Java front-end has been integrated. A [11]runtime library 21819 is available separately. 21820 + [12]ISO C99 support 21821 + [13]Chill front-end and runtime has been integrated. 21822 + Boehm garbage collector support in libobjc. 21823 + More support for various pragmas which appear in vendor 21824 include files 21825 * New Targets and Target Specific Improvements 21826 + [14]SPARC backend rewrite. 21827 + -mschedule=8000 will optimize code for PA8000 class 21828 processors; -mpa-risc-2-0 will generate code for PA2.0 21829 processors 21830 + Various micro-optimizations for the ia32 port. K6 21831 optimizations 21832 + Compiler will attempt to align doubles in the stack on the 21833 ia32 port 21834 + Alpha EV6 support 21835 + PowerPC 750 21836 + RS6000/PowerPC: -mcpu=401 was added as an alias for -mcpu=403. 21837 -mcpu=e603e was added to do -mcpu=603e and -msoft-float. 21838 + c3x, c4x 21839 + HyperSPARC 21840 + SparcLite86x 21841 + sh4 21842 + Support for new systems (OpenBSD, FreeBSD, UWIN, Interix, 21843 arm-linux) 21844 + vxWorks targets include support for vxWorks threads 21845 + StrongARM 110 and ARM9 support added. ARM Scheduling 21846 parameters rewritten. 21847 + Various changes to the MIPS port to avoid assembler macros, 21848 which in turn improves performance 21849 + Various performance improvements to the i960 port. 21850 + Major rewrite of ns32k port 21851 * Other significant improvements 21852 + [15]Ability to dump cfg information and display it using vcg. 21853 + The new faster scheme for fixing vendor header files is 21854 enabled by default. 21855 + Experimental internationalization support. 21856 + multibyte character support 21857 + Some compile-time speedups for pathological problems 21858 + Better support for complex types 21859 * Plus the usual mountain of bugfixes 21860 * Core compiler is based on the gcc2 development tree from Sept 30, 21861 1998, so we have all of the [16]features found in GCC 2.8. 21862 21863 Additional Changes in GCC 2.95.1 21864 21865 * Generic bugfixes and improvements 21866 + Various documentation fixes related to the GCC/EGCS merger. 21867 + Fix memory management bug which could lead to spurious aborts, 21868 core dumps or random parsing errors in the compiler. 21869 + Fix a couple bugs in the dwarf1 and dwarf2 debug record 21870 support. 21871 + Fix infinite loop in the CSE optimizer. 21872 + Avoid undefined behavior in compiler FP emulation code 21873 + Fix install problem when prefix is overridden on the make 21874 install command. 21875 + Fix problem with unwanted installation of assert.h on some 21876 systems. 21877 + Fix problem with finding the wrong assembler in a single tree 21878 build. 21879 + Avoid increasing the known alignment of a register that is 21880 already known to be a pointer. 21881 * Platform specific bugfixes and improvements 21882 + Codegen bugfix for prologue/epilogue for cpu32 target. 21883 + Fix long long code generation bug for the Coldfire target. 21884 + Fix various aborts in the SH compiler. 21885 + Fix bugs in libgcc support library for the SH. 21886 + Fix alpha ev6 code generation bug. 21887 + Fix problems with EXIT_SUCCESS/EXIT_FAILURE redefinitions on 21888 AIX platforms. 21889 + Fix -fpic code generation bug for rs6000/ppc svr4 targets. 21890 + Fix varargs/stdarg code generation bug for rs6000/ppc svr4 21891 targets. 21892 + Fix weak symbol handling for rs6000/ppc svr4 targets. 21893 + Fix various problems with 64bit code generation for the 21894 rs6000/ppc port. 21895 + Fix codegen bug which caused tetex to be mis-compiled on the 21896 x86. 21897 + Fix compiler abort in new cfg code exposed by x86 port. 21898 + Fix out of range array reference in code convert flat 21899 registers to the x87 stacked FP register file. 21900 + Fix minor vxworks configuration bug. 21901 + Fix return type of bsearch for SunOS 4.x. 21902 * Language & Runtime specific fixes. 21903 + The G++ signature extension has been deprecated. It will be 21904 removed in the next major release of G++. Use of signatures 21905 will result in a warning from the compiler. 21906 + Several bugs relating to templates and namespaces were fixed. 21907 + A bug that caused crashes when combining templates with -g on 21908 DWARF1 platforms was fixed. 21909 + Pointers-to-members, virtual functions, and multiple 21910 inheritance should now work together correctly. 21911 + Some code-generation bugs relating to function try blocks were 21912 fixed. 21913 + G++ is a little bit more lenient with certain archaic 21914 constructs than in GCC 2.95. 21915 + Fix to prevent shared library version #s from bring truncated 21916 to 1 digit 21917 + Fix missing std:: in the libstdc++ library. 21918 + Fix stream locking problems in libio. 21919 + Fix problem in java compiler driver. 21920 21921 Additional Changes in GCC 2.95.2 21922 21923 The -fstrict-aliasing is not enabled by default for GCC 2.95.2. While 21924 the optimizations performed by -fstrict-aliasing are valid according to 21925 the C and C++ standards, the optimization have caused some problems, 21926 particularly with old non-conforming code. 21927 21928 The GCC developers are experimenting with ways to warn users about code 21929 which violates the C/C++ standards, but those warnings are not ready 21930 for widespread use at this time. Rather than wait for those warnings 21931 the GCC developers have chosen to disable -fstrict-aliasing by default 21932 for the GCC 2.95.2 release. 21933 21934 We strongly encourage developers to find and fix code which violates 21935 the C/C++ standards as -fstrict-aliasing may be enabled by default in 21936 future releases. Use the option -fstrict-aliasing to re-enable these 21937 optimizations. 21938 * Generic bugfixes and improvements 21939 + Fix incorrectly optimized memory reference in global common 21940 subexpression elimination (GCSE) optimization pass. 21941 + Fix code generation bug in regmove.c in which it could 21942 incorrectly change a "const" value. 21943 + Fix bug in optimization of conditionals involving volatile 21944 memory references. 21945 + Avoid over-allocation of stack space for some procedures. 21946 + Fixed bug in the compiler which caused incorrect optimization 21947 of an obscure series of bit manipulations, shifts and 21948 arithmetic. 21949 + Fixed register allocator bug which caused teTeX to be 21950 mis-compiled on SPARC targets. 21951 + Avoid incorrect optimization of degenerate case statements for 21952 certain targets such as the ARM. 21953 + Fix out of range memory reference in the jump optimizer. 21954 + Avoid dereferencing null pointer in fix-header. 21955 + Fix test for GCC specific features so that it is possible to 21956 bootstrap with gcc-2.6.2 and older versions of GCC. 21957 + Fix typo in scheduler which could potentially cause out of 21958 range memory accesses. 21959 + Avoid incorrect loop reversal which caused incorrect code for 21960 certain loops on PowerPC targets. 21961 + Avoid incorrect optimization of switch statements on certain 21962 targets (for example the ARM). 21963 * Platform specific bugfixes and improvements 21964 + Work around bug in Sun V5.0 compilers which caused bootstrap 21965 comparison failures on SPARC targets. 21966 + Fix SPARC backend bug which caused aborts in final.c. 21967 + Fix sparc-hal-solaris2* configuration fragments. 21968 + Fix bug in sparc block profiling. 21969 + Fix obscure code generation bug for the PARISC targets. 21970 + Define __STDC_EXT__ for HPUX configurations. 21971 + Various POWERPC64 code generation bugfixes. 21972 + Fix abort for PPC targets using ELF (ex GNU/Linux). 21973 + Fix collect2 problems for AIX targets. 21974 + Correct handling of .file directive for PPC targets. 21975 + Fix bug in fix_trunc x86 patterns. 21976 + Fix x86 port to correctly pop the FP stack for functions that 21977 return structures in memory. 21978 + Fix minor bug in strlen x86 pattern. 21979 + Use stabs debugging instead of dwarf1 for x86-solaris targets. 21980 + Fix template repository code to handle leading underscore in 21981 mangled names. 21982 + Fix weak/weak alias support for OpenBSD. 21983 + GNU/Linux for the ARM has C++ compatible include files. 21984 * Language & Runtime specific fixes. 21985 + Fix handling of constructor attribute in the C front-end which 21986 caused problems building the Chill runtime library on some 21987 targets. 21988 + Fix minor problem merging type qualifiers in the C front-end. 21989 + Fix aliasing bug for pointers and references (C/C++). 21990 + Fix incorrect "non-constant initializer bug" when -traditional 21991 or -fwritable-strings is enabled. 21992 + Fix build error for Chill front-end on SunOS. 21993 + Do not complain about duplicate instantiations when using 21994 -frepo (C++). 21995 + Fix array bounds handling in C++ front-end which caused 21996 problems with dwarf debugging information in some 21997 circumstances. 21998 + Fix minor namespace problem. 21999 + Fix problem linking java programs. 22000 22001 Additional Changes in GCC 2.95.3 22002 22003 * Generic bugfixes and improvements 22004 + Fix numerous problems that caused incorrect optimization in 22005 the register reloading code. 22006 + Fix numerous problems that caused incorrect optimization in 22007 the loop optimizer. 22008 + Fix aborts in the functions build_insn_chain and scan_loops 22009 under some circumstances. 22010 + Fix an alias analysis bug. 22011 + Fix an infinite compilation bug in the combiner. 22012 + A few problems with complex number support have been fixed. 22013 + It is no longer possible for gcc to act as a fork bomb when 22014 installed incorrectly. 22015 + The -fpack-struct option should be recognized now. 22016 + Fixed a bug that caused incorrect code to be generated due to 22017 a lost stack adjustment. 22018 * Platform specific bugfixes and improvements 22019 + Support building ARM toolchains hosted on Windows. 22020 + Fix attribute calculations in ARM toolchains. 22021 + arm-linux support has been improved. 22022 + Fix a PIC failure on sparc targets. 22023 + On ix86 targets, the regparm attribute should now work 22024 reliably. 22025 + Several updates for the h8300 port. 22026 + Fix problem building libio with glibc 2.2. 22027 22028 22029 For questions related to the use of GCC, please consult these web 22030 pages and the [17]GCC manuals. If that fails, the 22031 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22032 web pages and the development of GCC are welcome on our developer 22033 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 22034 archives. 22035 22036 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 22037 distribution of this entire article is permitted in any medium, 22038 provided this notice is preserved. 22039 22040 These pages are [22]maintained by the GCC team. Last modified 22041 2022-10-26. 22042 22043 References 22044 22045 1. http://gcc.gnu.org/news/spill.html 22046 2. http://gcc.gnu.org/news/lcm.html 22047 3. http://gcc.gnu.org/news/cprop.html 22048 4. http://gcc.gnu.org/news/cfg.html 22049 5. http://gcc.gnu.org/news/dse.html 22050 6. http://gcc.gnu.org/news/hoist.html 22051 7. http://gcc.gnu.org/news/alias.html 22052 8. http://gcc.gnu.org/gcc-2.95/c++features.html 22053 9. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 22054 10. http://gcc.gnu.org/news/gcj-announce.txt 22055 11. http://gcc.gnu.org/news/javaannounce.html 22056 12. http://gcc.gnu.org/c99status.html 22057 13. http://gcc.gnu.org/news/chill.html 22058 14. http://gcc.gnu.org/news/sparc.html 22059 15. http://gcc.gnu.org/news/egcs-vcg.html 22060 16. http://gcc.gnu.org/egcs-1.0/features-2.8.html 22061 17. https://gcc.gnu.org/onlinedocs/ 22062 18. mailto:gcc-help (a] gcc.gnu.org 22063 19. mailto:gcc (a] gcc.gnu.org 22064 20. https://gcc.gnu.org/lists.html 22065 21. https://www.fsf.org/ 22066 22. https://gcc.gnu.org/about.html 22067 ====================================================================== 22068 http://gcc.gnu.org/gcc-2.95/caveats.html 22069 22070 GCC 2.95 Caveats 22071 22072 * GCC 2.95 will issue an error for invalid asm statements that had 22073 been silently accepted by earlier versions of the compiler. This is 22074 particularly noticeable when compiling older versions of the Linux 22075 kernel (2.0.xx). Please refer to the FAQ (as shipped with GCC 2.95) 22076 for more information on this issue. 22077 * GCC 2.95 implements type based alias analysis to disambiguate 22078 memory references. Some programs, particularly the Linux kernel 22079 violate ANSI/ISO aliasing rules and therefore may not operate 22080 correctly when compiled with GCC 2.95. Please refer to the FAQ (as 22081 shipped with GCC 2.95) for more information on this issue. 22082 * GCC 2.95 has a known bug in its handling of complex variables for 22083 64bit targets. Instead of silently generating incorrect code, GCC 22084 2.95 will issue a fatal error for situations it can not handle. 22085 This primarily affects the Fortran community as Fortran makes more 22086 use of complex variables than C or C++. 22087 * GCC 2.95 has an integrated libstdc++, but does not have an 22088 integrated libg++. Furthermore old libg++ releases will not work 22089 with GCC 2.95. You can retrieve a recent copy of libg++ from the 22090 [1]GCC ftp server. 22091 Note most C++ programs only need libstdc++. 22092 * Exception handling may not work with shared libraries, particularly 22093 on alphas, hppas, rs6000/powerpc and mips based platforms. 22094 Exception handling is known to work on x86 GNU/Linux platforms with 22095 shared libraries. 22096 * In general, GCC 2.95 is more rigorous about rejecting invalid C++ 22097 code or deprecated C++ constructs than G++ 2.7, G++ 2.8, EGCS 1.0, 22098 or EGCS 1.1. As a result it may be necessary to fix C++ code before 22099 it will compile with GCC 2.95. 22100 * G++ is also converting toward the ISO C++ standard; as a result 22101 code which was previously valid (and thus accepted by other 22102 compilers and older versions of g++) may no longer be accepted. The 22103 flag -fpermissive may allow some non-conforming code to compile 22104 with GCC 2.95. 22105 * GCC 2.95 compiled C++ code is not binary compatible with EGCS 22106 1.1.x, EGCS 1.0.x or GCC 2.8.x. 22107 * GCC 2.95 does not have changes from the GCC 2.8 tree that were made 22108 between Sept 30, 1998 and April 30, 1999 (the official end of the 22109 GCC 2.8 project). Future GCC releases will include all the changes 22110 from the defunct GCC 2.8 sources. 22111 22112 22113 For questions related to the use of GCC, please consult these web 22114 pages and the [2]GCC manuals. If that fails, the 22115 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22116 web pages and the development of GCC are welcome on our developer 22117 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 22118 22119 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 22120 distribution of this entire article is permitted in any medium, 22121 provided this notice is preserved. 22122 22123 These pages are [7]maintained by the GCC team. Last modified 22124 2022-10-26. 22125 22126 References 22127 22128 1. ftp://gcc.gnu.org/pub/gcc/infrastructure/libg++-2.8.1.3.tar.gz 22129 2. https://gcc.gnu.org/onlinedocs/ 22130 3. mailto:gcc-help (a] gcc.gnu.org 22131 4. mailto:gcc (a] gcc.gnu.org 22132 5. https://gcc.gnu.org/lists.html 22133 6. https://www.fsf.org/ 22134 7. https://gcc.gnu.org/about.html 22135 ====================================================================== 22136 http://gcc.gnu.org/egcs-1.1/index.html 22137 22138 EGCS 1.1 22139 22140 September 3, 1998: We are pleased to announce the release of EGCS 1.1. 22141 December 1, 1998: We are pleased to announce the release of EGCS 1.1.1. 22142 March 15, 1999: We are pleased to announce the release of EGCS 1.1.2. 22143 22144 EGCS is a free software project to further the development of the GNU 22145 compilers using an open development environment. 22146 22147 EGCS 1.1 is a major new release of the EGCS compiler system. It has 22148 been [1]extensively tested and is believed to be stable and suitable 22149 for widespread use. 22150 22151 EGCS 1.1 is based on an June 6, 1998 snapshot of the GCC 2.8 22152 development sources; it contains all of the new features found in GCC 22153 2.8.1 as well as all new development from GCC up to June 6, 1998. 22154 22155 EGCS 1.1 also contains many improvements and features not found in GCC 22156 or in older versions of EGCS: 22157 * Global common subexpression elimination and global constant/copy 22158 propagation (aka [2]gcse) 22159 * Ongoing improvements to the [3]alias analysis support to allow for 22160 better optimizations throughout the compiler. 22161 * Vastly improved [4]C++ compiler and integrated C++ runtime 22162 libraries. 22163 * Fixes for the /tmp symlink race security problems. 22164 * New targets including mips16, arm-thumb and 64 bit PowerPC. 22165 * Improvements to GNU Fortran (g77) compiler and runtime library made 22166 since g77 version 0.5.23. 22167 22168 See the [5]new features page for a more complete list of new features 22169 found in EGCS 1.1 releases. 22170 22171 EGCS 1.1.1 is a minor update to fix several serious problems in EGCS 22172 1.1: 22173 * General improvements and fixes 22174 + Avoid some stack overflows when compiling large functions. 22175 + Avoid incorrect loop invariant code motions. 22176 + Fix some core dumps on Linux kernel code. 22177 + Bring back the imake -Di386 and friends fix from EGCS 1.0.2. 22178 + Fix code generation problem in gcse. 22179 + Various documentation related fixes. 22180 * g++/libstdc++ improvements and fixes 22181 + MT safe EH fix for setjmp/longjmp based exception handling. 22182 + Fix a few bad interactions between optimization and exception 22183 handling. 22184 + Fixes for demangling of template names starting with "__". 22185 + Fix a bug that would fail to run destructors in some cases 22186 with -O2. 22187 + Fix 'new' of classes with virtual bases. 22188 + Fix crash building Qt on the Alpha. 22189 + Fix failure compiling WIFEXITED macro on GNU/Linux. 22190 + Fix some -frepo failures. 22191 * g77 and libf2c improvements and fixes 22192 + Various documentation fixes. 22193 + Avoid compiler crash on RAND intrinsic. 22194 + Fix minor bugs in makefiles exposed by BSD make programs. 22195 + Define _XOPEN_SOURCE for libI77 build to avoid potential 22196 problems on some 64-bit systems. 22197 + Fix problem with implicit endfile on rewind. 22198 + Fix spurious recursive I/O errors. 22199 * platform specific improvements and fixes 22200 + Match all versions of UnixWare7. 22201 + Do not assume x86 SVR4 or UnixWare targets can handle stabs. 22202 + Fix PPC/RS6000 LEGITIMIZE_ADDRESS macro and bug in conversion 22203 from unsigned ints to double precision floats. 22204 + Fix ARM ABI issue with NetBSD. 22205 + Fix a few arm code generation bugs. 22206 + Fixincludes will fix additional broken SCO OpenServer header 22207 files. 22208 + Fix a m68k backend bug which caused invalid offsets in reg+d 22209 addresses. 22210 + Fix problems with 64bit AIX 4.3 support. 22211 + Fix handling of long longs for varargs/stdarg functions on the 22212 ppc. 22213 + Minor fixes to CPP predefines for Windows. 22214 + Fix code generation problems with gpr<->fpr copies for 64bit 22215 ppc. 22216 + Fix a few coldfire code generation bugs. 22217 + Fix some more header file problems on SunOS 4.x. 22218 + Fix assert.h handling for RTEMS. 22219 + Fix Windows handling of TREE_SYMBOL_REFERENCED. 22220 + Fix x86 compiler abort in reg-stack pass. 22221 + Fix cygwin/windows problem with section attributes. 22222 + Fix Alpha code generation problem exposed by SMP Linux 22223 kernels. 22224 + Fix typo in m68k 32->64bit integer conversion. 22225 + Make sure target libraries build with -fPIC for PPC & Alpha 22226 targets. 22227 22228 EGCS 1.1.2 is a minor update to fix several serious problems in EGCS 22229 1.1.1: 22230 * General improvements and fixes 22231 + Fix bug in loop optimizer which caused the SPARC (and 22232 potentially other) ports to segfault. 22233 + Fix infinite recursion in alias analysis and combiner code. 22234 + Fix bug in regclass preferencing. 22235 + Fix incorrect loop reversal which caused incorrect code to be 22236 generated for several targets. 22237 + Fix return value for builtin memcpy. 22238 + Reduce compile time for certain loops which exposed quadratic 22239 behavior in the loop optimizer. 22240 + Fix bug which caused volatile memory to be written multiple 22241 times when only one write was needed/desired. 22242 + Fix compiler abort in caller-save.c 22243 + Fix combiner bug which caused incorrect code generation for 22244 certain division by constant operations. 22245 + Fix incorrect code generation due to a bug in range check 22246 optimizations. 22247 + Fix incorrect code generation due to mis-handling of clobbered 22248 values in CSE. 22249 + Fix compiler abort/segfault due to incorrect register 22250 splitting when unrolling loops. 22251 + Fix code generation involving autoincremented addresses with 22252 ternary operators. 22253 + Work around bug in the scheduler which caused qt to be 22254 mis-compiled on some platforms. 22255 + Fix code generation problems with -fshort-enums. 22256 + Tighten security for temporary files. 22257 + Improve compile time for codes which make heavy use of 22258 overloaded functions. 22259 + Fix multiply defined constructor/destructor symbol problems. 22260 + Avoid setting bogus RPATH environment variable during 22261 bootstrap. 22262 + Avoid GNU-make dependencies in the texinfo subdir. 22263 + Install CPP wrapper script in $(prefix)/bin if --enable-cpp. 22264 --enable-cpp=<dirname> can be used to specify an additional 22265 install directory for the cpp wrapper script. 22266 + Fix CSE bug which caused incorrect label-label refs to appear 22267 on some platforms. 22268 + Avoid linking in EH routines from libgcc if they are not 22269 needed. 22270 + Avoid obscure bug in aliasing code. 22271 + Fix bug in weak symbol handling. 22272 * Platform-specific improvements and fixes 22273 + Fix detection of PPro/PII on Unixware 7. 22274 + Fix compiler segfault when building spec99 and other programs 22275 for SPARC targets. 22276 + Fix code-generation bugs for integer and floating point 22277 conditional move instructions on the PPro/PII. 22278 + Use fixincludes to fix byteorder problems on i?86-*-sysv. 22279 + Fix build failure for the arc port. 22280 + Fix floating point format configuration for i?86-gnu port. 22281 + Fix problems with hppa1.0-hp-hpux10.20 configuration when 22282 threads are enabled. 22283 + Fix coldfire code generation bugs. 22284 + Fix "unrecognized insn" problems for Alpha and PPC ports. 22285 + Fix h8/300 code generation problem with floating point values 22286 in memory. 22287 + Fix unrecognized insn problems for the m68k port. 22288 + Fix namespace-pollution problem for the x86 port. 22289 + Fix problems with old assembler on x86 NeXT systems. 22290 + Fix PIC code-generation problems for the SPARC port. 22291 + Fix minor bug with LONG_CALLS in PowerPC SVR4 support. 22292 + Fix minor ISO namespace violation in Alpha varargs/stdarg 22293 support. 22294 + Fix incorrect "braf" instruction usage for the SH port. 22295 + Fix minor bug in va-sh which prevented its use with -ansi. 22296 + Fix problems recognizing and supporting FreeBSD. 22297 + Handle OpenBSD systems correctly. 22298 + Minor fixincludes fix for Digital UNIX 4.0B. 22299 + Fix problems with ctors/dtors in SCO shared libraries. 22300 + Abort instead of generating incorrect code for PPro/PII 22301 floating point conditional moves. 22302 + Avoid multiply defined symbols on GNU/Linux systems using 22303 libc-5.4.xx. 22304 + Fix abort in alpha compiler. 22305 * Fortran-specific fixes 22306 + Fix the IDate intrinsic (VXT) (in libg2c) so the returned year 22307 is in the documented, non-Y2K-compliant range of 0-99, instead 22308 of being returned as 100 in the year 2000. 22309 + Fix the `Date_and_Time' intrinsic (in libg2c) to return the 22310 milliseconds value properly in Values(8). 22311 + Fix the `LStat' intrinsic (in libg2c) to return device-ID 22312 information properly in SArray(7). 22313 22314 Each release includes installation instructions in both HTML and 22315 plaintext forms (see the INSTALL directory in the toplevel directory of 22316 the distribution). However, we also keep the most up to date 22317 installation instructions and [6]build/test status on our web page. We 22318 will update those pages as new information becomes available. 22319 22320 The EGCS project would like to thank the numerous people that have 22321 contributed new features, test results, bugfixes, etc. This [7]amazing 22322 group of volunteers is what makes EGCS successful. 22323 22324 And finally, we can't in good conscience fail to mention some 22325 [8]caveats to using EGCS 1.1. 22326 22327 Download EGCS from egcs.cygnus.com (USA California). 22328 22329 The EGCS 1.1 release is also available on many mirror sites. 22330 [9]Goto mirror list to find a closer site. 22331 22332 22333 For questions related to the use of GCC, please consult these web 22334 pages and the [10]GCC manuals. If that fails, the 22335 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22336 web pages and the development of GCC are welcome on our developer 22337 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 22338 archives. 22339 22340 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 22341 distribution of this entire article is permitted in any medium, 22342 provided this notice is preserved. 22343 22344 These pages are [15]maintained by the GCC team. Last modified 22345 2023-01-21. 22346 22347 References 22348 22349 1. http://gcc.gnu.org/egcs-1.1/egcs-1.1-test.html 22350 2. http://gcc.gnu.org/news/gcse.html 22351 3. http://gcc.gnu.org/news/alias.html 22352 4. http://gcc.gnu.org/egcs-1.1/c++features.html 22353 5. http://gcc.gnu.org/egcs-1.1/features.html 22354 6. http://gcc.gnu.org/egcs-1.1/buildstat.html 22355 7. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 22356 8. http://gcc.gnu.org/egcs-1.1/caveats.html 22357 9. http://gcc.gnu.org/mirrors.html 22358 10. https://gcc.gnu.org/onlinedocs/ 22359 11. mailto:gcc-help (a] gcc.gnu.org 22360 12. mailto:gcc (a] gcc.gnu.org 22361 13. https://gcc.gnu.org/lists.html 22362 14. https://www.fsf.org/ 22363 15. https://gcc.gnu.org/about.html 22364 ====================================================================== 22365 http://gcc.gnu.org/egcs-1.1/features.html 22366 22367 EGCS 1.1 new features 22368 22369 * Integrated GNU Fortran (g77) compiler and runtime library with 22370 improvements, based on g77 version 0.5.23. 22371 * Vast improvements in the C++ compiler; so many they have [1]page of 22372 their own! 22373 * Compiler implements [2]global common subexpression elimination and 22374 global copy/constant propagation. 22375 * More major improvements in the [3]alias analysis code. 22376 * More major improvements in the exception handling code to improve 22377 performance, lower static overhead and provide the infrastructure 22378 for future improvements. 22379 * The infamous /tmp symlink race security problems have been fixed. 22380 * The regmove optimization pass has been nearly completely rewritten 22381 to improve performance of generated code. 22382 * The compiler now recomputes register usage information before local 22383 register allocation. By providing more accurate information to the 22384 priority based allocator, we get better register allocation. 22385 * The register reloading phase of the compiler optimizes spill code 22386 much better than in previous releases. 22387 * Some bad interactions between the register allocator and 22388 instruction scheduler have been fixed, resulting in much better 22389 code for certain programs. Additionally, we have tuned the 22390 scheduler in various ways to improve performance of generated code 22391 for some architectures. 22392 * The compiler's branch shortening algorithms have been significantly 22393 improved to work better on targets which align jump targets. 22394 * The compiler now supports -Os to prefer optimizing for code space 22395 over optimizing for code speed. 22396 * The compiler will now totally eliminate library calls which compute 22397 constant values. This primarily helps targets with no integer 22398 div/mul support and targets without floating point support. 22399 * The compiler now supports an extensive "--help" option. 22400 * cpplib has been greatly improved and may be suitable for limited 22401 use. 22402 * Memory footprint for the compiler has been significantly reduced 22403 for some pathological cases. 22404 * The time to build EGCS has been improved for certain targets 22405 (particularly the alpha and mips platforms). 22406 * Many infrastructure improvements throughout the compiler, plus the 22407 usual mountain of bugfixes and minor improvements. 22408 * Target dependent improvements: 22409 + SPARC port now includes V8 plus and V9 support as well as 22410 performance tuning for Ultra class machines. The SPARC port 22411 now uses the Haifa scheduler. 22412 + Alpha port has been tuned for the EV6 processor and has an 22413 optimized expansion of memcpy/bzero. The Alpha port now uses 22414 the Haifa scheduler. 22415 + RS6000/PowerPC: support for the Power64 architecture and AIX 22416 4.3. The RS6000/PowerPC port now uses the Haifa scheduler. 22417 + x86: Alignment of static store data and jump targets is per 22418 Intel recommendations now. Various improvements throughout the 22419 x86 port to improve performance on Pentium processors 22420 (including improved epilogue sequences for Pentium chips and 22421 backend improvements which should help register allocation on 22422 all x86 variants. Conditional move support has been fixed and 22423 enabled for PPro processors. The x86 port also better supports 22424 64bit operations now. Unixware 7, a System V Release 5 target, 22425 is now supported and SCO OpenServer targets can support GAS. 22426 + MIPS has improved multiply/multiply-add support and now 22427 includes mips16 ISA support. 22428 + M68k has many micro-optimizations and Coldfire fixes. 22429 * Core compiler is based on the GCC development tree from June 9, 22430 1998, so we have all of the [4]features found in GCC 2.8. 22431 22432 22433 For questions related to the use of GCC, please consult these web 22434 pages and the [5]GCC manuals. If that fails, the 22435 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22436 web pages and the development of GCC are welcome on our developer 22437 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 22438 22439 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 22440 distribution of this entire article is permitted in any medium, 22441 provided this notice is preserved. 22442 22443 These pages are [10]maintained by the GCC team. Last modified 22444 2022-10-26. 22445 22446 References 22447 22448 1. http://gcc.gnu.org/egcs-1.1/c++features.html 22449 2. http://gcc.gnu.org/news/gcse.html 22450 3. http://gcc.gnu.org/news/alias.html 22451 4. http://gcc.gnu.org/egcs-1.0/features-2.8.html 22452 5. https://gcc.gnu.org/onlinedocs/ 22453 6. mailto:gcc-help (a] gcc.gnu.org 22454 7. mailto:gcc (a] gcc.gnu.org 22455 8. https://gcc.gnu.org/lists.html 22456 9. https://www.fsf.org/ 22457 10. https://gcc.gnu.org/about.html 22458 ====================================================================== 22459 http://gcc.gnu.org/egcs-1.1/caveats.html 22460 22461 EGCS 1.1 Caveats 22462 22463 * EGCS has an integrated libstdc++, but does not have an integrated 22464 libg++. Furthermore old libg++ releases will not work with EGCS; HJ 22465 Lu has made a libg++-2.8.1.2 snapshot available which may work with 22466 EGCS. 22467 Note most C++ programs only need libstdc++. 22468 * Exception handling may not work with shared libraries, particularly 22469 on alphas, hppas, rs6000/powerpc and mips based platforms. 22470 Exception handling is known to work on x86-linux platforms with 22471 shared libraries. 22472 * Some versions of the Linux kernel have bugs which prevent them from 22473 being compiled or from running when compiled by EGCS. See the FAQ 22474 (as shipped with EGCS 1.1) for additional information. 22475 * In general, EGCS is more rigorous about rejecting invalid C++ code 22476 or deprecated C++ constructs than g++-2.7, g++-2.8 or EGCS 1.0. As 22477 a result it may be necessary to fix C++ code before it will compile 22478 with EGCS. 22479 * G++ is also converting toward the ISO C++ standard; as a result 22480 code which was previously valid (and thus accepted by other 22481 compilers and older versions of g++) may no longer be accepted. 22482 * EGCS 1.1 compiled C++ code is not binary compatible with EGCS 1.0.x 22483 or GCC 2.8.x due to changes necessary to support thread safe 22484 exception handling. 22485 22486 22487 For questions related to the use of GCC, please consult these web 22488 pages and the [1]GCC manuals. If that fails, the 22489 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22490 web pages and the development of GCC are welcome on our developer 22491 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 22492 22493 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 22494 distribution of this entire article is permitted in any medium, 22495 provided this notice is preserved. 22496 22497 These pages are [6]maintained by the GCC team. Last modified 22498 2022-10-26. 22499 22500 References 22501 22502 1. https://gcc.gnu.org/onlinedocs/ 22503 2. mailto:gcc-help (a] gcc.gnu.org 22504 3. mailto:gcc (a] gcc.gnu.org 22505 4. https://gcc.gnu.org/lists.html 22506 5. https://www.fsf.org/ 22507 6. https://gcc.gnu.org/about.html 22508 ====================================================================== 22509 http://gcc.gnu.org/egcs-1.0/index.html 22510 22511 EGCS 1.0 22512 22513 December 3, 1997: We are pleased to announce the release of EGCS 1.0. 22514 January 6, 1998: We are pleased to announce the release of EGCS 1.0.1. 22515 March 16, 1998: We are pleased to announce the release of EGCS 1.0.2. 22516 May 15, 1998 We are pleased to announce the release of EGCS 1.0.3. 22517 22518 EGCS is a collaborative effort involving several groups of hackers 22519 using an open development model to accelerate development and testing 22520 of GNU compilers and runtime libraries. 22521 22522 An important goal of EGCS is to allow wide scale testing of 22523 experimental features and optimizations; therefore, EGCS contains some 22524 features and optimizations which are still under development. However, 22525 EGCS has been carefully tested and should be comparable in quality to 22526 most GCC releases. 22527 22528 EGCS 1.0 is based on an August 2, 1997 snapshot of the GCC 2.8 22529 development sources; it contains nearly all of the new features found 22530 in GCC 2.8. 22531 22532 EGCS 1.0 also contains many improvements and features not found in GCC 22533 2.7 and even the GCC 2.8 series (which was released after the original 22534 EGCS 1.0 release). 22535 * Integrated C++ runtime libraries, including support for most major 22536 GNU/Linux systems! 22537 * The integrated libstdc++ library includes a verbatim copy of SGI's 22538 STL release. 22539 * Integrated GNU Fortran compiler. 22540 * New instruction scheduler. 22541 * New alias analysis code. 22542 22543 See the [1]new features page for a more complete list of new features. 22544 22545 EGCS 1.0.1 is a minor update to the EGCS 1.0 compiler to fix a few 22546 critical bugs and add support for Red Hat 5.0 Linux. Changes since the 22547 EGCS 1.0 release: 22548 * Add support for Red Hat 5.0 Linux and better support for Linux 22549 systems using glibc2. 22550 Many programs failed to link when compiled with EGCS 1.0 on Red Hat 22551 5.0 or on systems with newer versions of glibc2. EGCS 1.0.1 should 22552 fix these problems. 22553 * Compatibility with both EGCS 1.0 and GCC 2.8 libgcc exception 22554 handling interfaces. 22555 To avoid future compatibility problems, we strongly urge anyone who 22556 is planning on distributing shared libraries that contain C++ code 22557 to upgrade to EGCS 1.0.1 first. 22558 Soon after EGCS 1.0 was released, the GCC developers made some 22559 incompatible changes in libgcc's exception handling interfaces. 22560 These changes were needed to solve problems on some platforms. This 22561 means that GCC 2.8.0, when released, will not be seamlessly 22562 compatible with shared libraries built by EGCS 1.0. The reason is 22563 that the libgcc.a in GCC 2.8.0 will not contain a function needed 22564 by the old interface. 22565 The result of this is that there may be compatibility problems with 22566 shared libraries built by EGCS 1.0 when used with GCC 2.8.0. 22567 With EGCS 1.0.1, generated code uses the new (GCC 2.8.0) interface, 22568 and libgcc.a has the support routines for both the old and the new 22569 interfaces (so EGCS 1.0.1 and EGCS 1.0 code can be freely mixed, 22570 and EGCS 1.0.1 and GCC 2.8.0 code can be freely mixed). 22571 The maintainers of GCC 2.x have decided against including seamless 22572 support for the old interface in 2.8.0, since it was never 22573 "official", so to avoid future compatibility problems we recommend 22574 against distributing any shared libraries built by EGCS 1.0 that 22575 contain C++ code (upgrade to 1.0.1 and use that). 22576 * Various bugfixes in the x86, hppa, mips, and rs6000/ppc back ends. 22577 The x86 changes fix code generation errors exposed when building 22578 glibc2 and the usual GNU/Linux dynamic linker (ld.so). 22579 The hppa change fixes a compiler abort when configured for use with 22580 RTEMS. 22581 The MIPS changes fix problems with the definition of LONG_MAX on 22582 newer systems, allow for command line selection of the target ABI, 22583 and fix one code generation problem. 22584 The rs6000/ppc change fixes some problems with passing structures 22585 to varargs/stdarg functions. 22586 * A few machine independent bugfixes, mostly to fix code generation 22587 errors when building Linux kernels or glibc. 22588 * Fix a few critical exception handling and template bugs in the C++ 22589 compiler. 22590 * Fix Fortran namelist bug on alphas. 22591 * Fix build problems on x86-solaris systems. 22592 22593 EGCS 1.0.2 is a minor update to the EGCS 1.0.1 compiler to fix several 22594 serious problems in EGCS 1.0.1. 22595 * General improvements and fixes 22596 + Memory consumption significantly reduced, especially for 22597 templates and inline functions. 22598 + Fix various problems with glibc2.1. 22599 + Fix loop optimization bug exposed by rs6000/ppc port. 22600 + Fix to avoid potential code generation problems in jump.c. 22601 + Fix some undefined symbol problems in dwarf1 debug support. 22602 * g++/libstdc++ improvements and fixes 22603 + libstdc++ in the EGCS release has been updated and should be 22604 link compatible with libstdc++-2.8. 22605 + Various fixes in libio/libstdc++ to work better on GNU/Linux 22606 systems. 22607 + Fix problems with duplicate symbols on systems that do not 22608 support weak symbols. 22609 + Memory corruption bug and undefined symbols in bastring have 22610 been fixed. 22611 + Various exception handling fixes. 22612 + Fix compiler abort for very long thunk names. 22613 * g77 improvements and fixes 22614 + Fix compiler crash for omitted bound in Fortran CASE 22615 statement. 22616 + Add missing entries to g77 lang-options. 22617 + Fix problem with -fpedantic in the g77 compiler. 22618 + Fix "backspace" problem with g77 on alphas. 22619 + Fix x86 backend problem with Fortran literals and -fpic. 22620 + Fix some of the problems with negative subscripts for g77 on 22621 alphas. 22622 + Fixes for Fortran builds on cygwin32/mingw32. 22623 * platform specific improvements and fixes 22624 + Fix long double problems on x86 (exposed by glibc). 22625 + x86 ports define i386 again to keep imake happy. 22626 + Fix exception handling support on NetBSD ports. 22627 + Several changes to collect2 to fix many problems with AIX. 22628 + Define __ELF__ for GNU/Linux on rs6000. 22629 + Fix -mcall-linux problem on GNU/Linux on rs6000. 22630 + Fix stdarg/vararg problem for GNU/Linux on rs6000. 22631 + Allow autoconf to select a proper install problem on AIX 3.1. 22632 + m68k port support includes -mcpu32 option as well as cpu32 22633 multilibs. 22634 + Fix stdarg bug for irix6. 22635 + Allow EGCS to build on irix5 without the gnu assembler. 22636 + Fix problem with static linking on sco5. 22637 + Fix bootstrap on sco5 with native compiler. 22638 + Fix for abort building newlib on H8 target. 22639 + Fix fixincludes handling of math.h on SunOS. 22640 + Minor fix for Motorola 3300 m68k systems. 22641 22642 EGCS 1.0.3 is a minor update to the EGCS 1.0.2 compiler to fix a few 22643 problems reported by Red Hat for builds of Red Hat 5.1. 22644 * Generic bugfixes: 22645 + Fix a typo in the libio library which resulted in incorrect 22646 behavior of istream::get. 22647 + Fix the Fortran negative array index problem. 22648 + Fix a major problem with the ObjC runtime thread support 22649 exposed by glibc2. 22650 + Reduce memory consumption of the Haifa scheduler. 22651 * Target specific bugfixes: 22652 + Fix one x86 floating point code generation bug exposed by 22653 glibc2 builds. 22654 + Fix one x86 internal compiler error exposed by glibc2 builds. 22655 + Fix profiling bugs on the Alpha. 22656 + Fix ImageMagick & emacs 20.2 build problems on the Alpha. 22657 + Fix rs6000/ppc bug when converting values from integer types 22658 to floating point types. 22659 22660 The EGCS 1.0 releases include installation instructions in both HTML 22661 and plaintext forms (see the INSTALL directory in the toplevel 22662 directory of the distribution). However, we also keep the most up to 22663 date installation instructions and [2]build/test status on our web 22664 page. We will update those pages as new information becomes available. 22665 22666 And, we can't in good conscience fail to mention some [3]caveats to 22667 using EGCS. 22668 22669 Update: Big thanks to Stanford for providing a high speed link for 22670 downloading EGCS (go.cygnus.com)! 22671 22672 Download EGCS from ftp.cygnus.com (USA California) or go.cygnus.com 22673 (USA California -- High speed link provided by Stanford). 22674 22675 The EGCS 1.0 release is also available many mirror sites. 22676 [4]Goto mirror list to find a closer site 22677 22678 We'd like to thank the numerous people that have contributed new 22679 features, test results, bugfixes, etc. Unfortunately, they're far too 22680 numerous to mention by name. 22681 22682 22683 For questions related to the use of GCC, please consult these web 22684 pages and the [5]GCC manuals. If that fails, the 22685 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22686 web pages and the development of GCC are welcome on our developer 22687 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 22688 22689 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 22690 distribution of this entire article is permitted in any medium, 22691 provided this notice is preserved. 22692 22693 These pages are [10]maintained by the GCC team. Last modified 22694 2023-01-21. 22695 22696 References 22697 22698 1. http://gcc.gnu.org/egcs-1.0/features.html 22699 2. http://gcc.gnu.org/egcs-1.0/buildstat.html 22700 3. http://gcc.gnu.org/egcs-1.0/caveats.html 22701 4. http://gcc.gnu.org/mirrors.html 22702 5. https://gcc.gnu.org/onlinedocs/ 22703 6. mailto:gcc-help (a] gcc.gnu.org 22704 7. mailto:gcc (a] gcc.gnu.org 22705 8. https://gcc.gnu.org/lists.html 22706 9. https://www.fsf.org/ 22707 10. https://gcc.gnu.org/about.html 22708 ====================================================================== 22709 http://gcc.gnu.org/egcs-1.0/features.html 22710 22711 EGCS 1.0 features 22712 22713 * Core compiler is based on the gcc2 development tree from Aug 2, 22714 1997, so we have most of the [1]features found in GCC 2.8. 22715 * Integrated GNU Fortran compiler based on g77-0.5.22-19970929. 22716 * Vast improvements in the C++ compiler; so many they have [2]page of 22717 their own! 22718 * Integrated C++ runtime libraries, including support for most major 22719 GNU/Linux systems! 22720 * New instruction scheduler from IBM Haifa which includes support for 22721 function wide instruction scheduling as well as superscalar 22722 scheduling. 22723 * Significantly improved alias analysis code. 22724 * Improved register allocation for two address machines. 22725 * Significant code generation improvements for Fortran code on 22726 Alphas. 22727 * Various optimizations from the g77 project as well as improved loop 22728 optimizations. 22729 * Dwarf2 debug format support for some targets. 22730 * egcs libstdc++ includes the SGI STL implementation without changes. 22731 * As a result of these and other changes, egcs libstc++ is not binary 22732 compatible with previous releases of libstdc++. 22733 * Various new ports -- UltraSPARC, Irix6.2 & Irix6.3 support, The SCO 22734 Openserver 5 family (5.0.{0,2,4} and Internet FastStart 1.0 and 22735 1.1), Support for RTEMS on several embedded targets, Support for 22736 arm-linux, Mitsubishi M32R, Hitachi H8/S, Matsushita MN102 and 22737 MN103, NEC V850, Sparclet, Solaris & GNU/Linux on PowerPCs, etc. 22738 * Integrated testsuites for gcc, g++, g77, libstdc++ and libio. 22739 * RS6000/PowerPC ports generate code which can run on all 22740 RS6000/PowerPC variants by default. 22741 * -mcpu= and -march= switches for the x86 port to allow better 22742 control over how the x86 port generates code. 22743 * Includes the template repository patch (aka repo patch); note the 22744 new template code makes repo obsolete for ELF systems using gnu-ld 22745 such as GNU/Linux. 22746 * Plus the usual assortment of bugfixes and improvements. 22747 22748 22749 For questions related to the use of GCC, please consult these web 22750 pages and the [3]GCC manuals. If that fails, the 22751 [4]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22752 web pages and the development of GCC are welcome on our developer 22753 list at [5]gcc (a] gcc.gnu.org. All of [6]our lists have public archives. 22754 22755 Copyright (C) [7]Free Software Foundation, Inc. Verbatim copying and 22756 distribution of this entire article is permitted in any medium, 22757 provided this notice is preserved. 22758 22759 These pages are [8]maintained by the GCC team. Last modified 22760 2022-10-26. 22761 22762 References 22763 22764 1. http://gcc.gnu.org/egcs-1.0/features-2.8.html 22765 2. http://gcc.gnu.org/egcs-1.0/c++features.html 22766 3. https://gcc.gnu.org/onlinedocs/ 22767 4. mailto:gcc-help (a] gcc.gnu.org 22768 5. mailto:gcc (a] gcc.gnu.org 22769 6. https://gcc.gnu.org/lists.html 22770 7. https://www.fsf.org/ 22771 8. https://gcc.gnu.org/about.html 22772 ====================================================================== 22773 http://gcc.gnu.org/egcs-1.0/caveats.html 22774 22775 EGCS 1.0 Caveats 22776 22777 * EGCS has an integrated libstdc++, but does not have an integrated 22778 libg++. Furthermore old libg++ releases will not work with egc; HJ 22779 Lu has made a libg++-2.8.1.2 available which may work with EGCS. 22780 Note most C++ programs only need libstdc++. 22781 * Note that using -pedantic or -Wreturn-type can cause an explosion 22782 in the amount of memory needed for template-heavy C++ code, such as 22783 code that uses STL. Also note that -Wall includes -Wreturn-type, so 22784 if you use -Wall you will need to specify -Wno-return-type to turn 22785 it off. 22786 * Exception handling may not work with shared libraries, particularly 22787 on alphas, hppas, and mips based platforms. Exception handling is 22788 known to work on x86-linux platforms with shared libraries. 22789 * Some versions of the Linux kernel have bugs which prevent them from 22790 being compiled or from running when compiled by EGCS. See the FAQ 22791 (as shipped with EGCS 1.0) for additional information. 22792 * In general, EGCS is more rigorous about rejecting invalid C++ code 22793 or deprecated C++ constructs than G++ 2.7. As a result it may be 22794 necessary to fix C++ code before it will compile with EGCS. 22795 * G++ is also aggressively tracking the C++ standard; as a result 22796 code which was previously valid (and thus accepted by other 22797 compilers and older versions of G++) may no longer be accepted. 22798 * EGCS 1.0 may not work with Red Hat Linux 5.0 on all targets. EGCS 22799 1.0.x and later releases should work with Red Hat Linux 5.0. 22800 22801 22802 For questions related to the use of GCC, please consult these web 22803 pages and the [1]GCC manuals. If that fails, the 22804 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 22805 web pages and the development of GCC are welcome on our developer 22806 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 22807 22808 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 22809 distribution of this entire article is permitted in any medium, 22810 provided this notice is preserved. 22811 22812 These pages are [6]maintained by the GCC team. Last modified 22813 2022-10-26. 22814 22815 References 22816 22817 1. https://gcc.gnu.org/onlinedocs/ 22818 2. mailto:gcc-help (a] gcc.gnu.org 22819 3. mailto:gcc (a] gcc.gnu.org 22820 4. https://gcc.gnu.org/lists.html 22821 5. https://www.fsf.org/ 22822 6. https://gcc.gnu.org/about.html 22823 ====================================================================== 22824
Indexes created Tue Oct 27 00:25:24 UTC 2026