NEWS revision 1.1.1.10
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-10/index.html 9 GCC 10 Release Series 10 11 June 28, 2022 12 13 The [1]GNU project and the GCC developers are pleased to announce the 14 release of GCC 10.4. 15 16 This release is a bug-fix release, containing fixes for regressions in 17 GCC 10.3 relative to previous releases of GCC. 18 19 Release History 20 21 GCC 10.4 22 June 28, 2022 ([2]changes, [3]documentation) 23 24 GCC 10.3 25 April 8, 2021 ([4]changes, [5]documentation) 26 27 GCC 10.2 28 July 23, 2020 ([6]changes, [7]documentation) 29 30 GCC 10.1 31 May 7, 2020 ([8]changes, [9]documentation) 32 33 References and Acknowledgements 34 35 GCC used to stand for the GNU C Compiler, but since the compiler 36 supports several other languages aside from C, it now stands for the 37 GNU Compiler Collection. 38 39 A list of [10]successful builds is updated as new information becomes 40 available. 41 42 The GCC developers would like to thank the numerous people that have 43 contributed new features, improvements, bug fixes, and other changes as 44 well as test results to GCC. This [11]amazing group of volunteers is 45 what makes GCC successful. 46 47 For additional information about GCC please refer to the [12]GCC 48 project web site or contact the [13]GCC development mailing list. 49 50 To obtain GCC please use [14]our mirror sites or [15]our version 51 control system. 52 53 54 For questions related to the use of GCC, please consult these web 55 pages and the [16]GCC manuals. If that fails, the 56 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 57 web pages and the development of GCC are welcome on our developer 58 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 59 archives. 60 61 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 62 distribution of this entire article is permitted in any medium, 63 provided this notice is preserved. 64 65 These pages are [21]maintained by the GCC team. Last modified 66 2022-06-28[22]. 67 68 References 69 70 1. http://www.gnu.org/ 71 2. http://gcc.gnu.org/gcc-10/changes.html 72 3. http://gcc.gnu.org/onlinedocs/10.4.0/ 73 4. http://gcc.gnu.org/gcc-10/changes.html 74 5. http://gcc.gnu.org/onlinedocs/10.3.0/ 75 6. http://gcc.gnu.org/gcc-10/changes.html 76 7. http://gcc.gnu.org/onlinedocs/10.2.0/ 77 8. http://gcc.gnu.org/gcc-10/changes.html 78 9. http://gcc.gnu.org/onlinedocs/10.1.0/ 79 10. http://gcc.gnu.org/gcc-10/buildstat.html 80 11. http://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Contributors.html 81 12. http://gcc.gnu.org/index.html 82 13. mailto:gcc (a] gcc.gnu.org 83 14. http://gcc.gnu.org/mirrors.html 84 15. http://gcc.gnu.org/git.html 85 16. https://gcc.gnu.org/onlinedocs/ 86 17. mailto:gcc-help (a] gcc.gnu.org 87 18. mailto:gcc (a] gcc.gnu.org 88 19. https://gcc.gnu.org/lists.html 89 20. https://www.fsf.org/ 90 21. https://gcc.gnu.org/about.html 91 22. http://validator.w3.org/check/referer 92 ====================================================================== 93 http://gcc.gnu.org/gcc-10/changes.html 94 GCC 10 Release Series 95 Changes, New Features, and Fixes 96 97 This page is a "brief" summary of some of the huge number of 98 improvements in GCC 10. You may also want to check out our [1]Porting 99 to GCC 10 page and the [2]full GCC documentation. 100 101 Caveats 102 103 * An ABI incompatibility between C++14 and C++17 has been fixed. On 104 some targets a class with a zero-sized subobject would be passed 105 incorrectly when compiled as C++17 or C++20. See the [3]C++ notes 106 below for more details. 107 * The deprecated Profile Mode and array_allocator extensions have 108 been removed from libstdc++. 109 * The non-standard std::__is_nullptr_t type trait is deprecated and 110 will be removed from libstdc++ in a future release. The standard 111 trait std::is_null_pointer should be instead. 112 * The minimum version of the [4]MPFR library required for building 113 GCC has been increased to version 3.1.0 (released 2011-10-03). 114 * The automatic template instantiation at link time (-frepo) has been 115 removed. 116 * The --param allow-store-data-races internal parameter has been 117 removed in favor of a new official option -fallow-store-data-races. 118 While default behavior is unchanged and the new option allows to 119 correctly maintain a per compilation unit setting across link-time 120 optimization, alteration of the default via --param 121 allow-store-data-races will now be diagnosed and build systems have 122 to be adjusted accordingly. 123 * Offloading to Heterogeneous System Architecture Intermediate 124 Language (HSAIL) has been deprecated and will likely be removed in 125 a future release. 126 * The type of the std::iterator base class of 127 std::istreambuf_iterator was changed in C++98 mode to be consistent 128 with C++11 and later standards. See the [5]libstdc++ notes below 129 for more details. 130 131 General Improvements 132 133 * New built-in functions: 134 + The [6]__has_builtin built-in preprocessor operator can be 135 used to query support for built-in functions provided by GCC 136 and other compilers that support it. 137 + __builtin_roundeven for the corresponding function from 138 ISO/IEC TS 18661. 139 * New command-line options: 140 + [7]-fallocation-dce removes unneeded pairs of new and delete 141 operators. 142 + [8]-fprofile-partial-training can now be used to inform the 143 compiler that code paths not covered by the training run 144 should not be optimized for size. 145 + [9]-fprofile-reproducible controls level of reproducibility of 146 profile gathered by [10]-fprofile-generate. This makes it 147 possible to rebuild program with same outcome which is useful, 148 for example, for distribution packages. 149 + [11]-fprofile-prefix-path can be used in combination with 150 -fprofile-generate=profile_dir and -fprofile-use=profile_dir 151 to inform GCC where the base directory of build source tree is 152 in case it differs between instrumentation and optimized 153 builds. 154 + [12]-fanalyzer enables a new static analysis pass and 155 associated warnings. This pass performs a time-consuming 156 exploration of paths through the code in the hope of detecting 157 various common errors, such as double-free bugs. This option 158 should be regarded as experimental in this release. In 159 particular, analysis of non-C code is unlikely to work. 160 * Inter-procedural optimization improvements: 161 + The inter-procedural scalar replacement of aggregates 162 (IPA-SRA) pass was re-implemented to work at link-time and can 163 now also remove computing and returning unused return values. 164 + [13]-finline-functions is now enabled at -O2 and was retuned 165 for better code size versus runtime performance trade-offs. 166 Inliner heuristics was also significantly sped up to avoid 167 negative impact to -flto -O2 compile times. 168 + Inliner heuristics and function cloning can now use 169 value-range information to predict effectivity of individual 170 transformations. 171 + During link-time optimization the C++ One Definition Rule is 172 used to increase precision of type based alias analysis. 173 * Link-time optimization improvements: 174 + A new binary [14]lto-dump has been added. It dumps various 175 information about LTO bytecode object files. 176 + The parallel phase of the LTO can automatically detect a 177 running make's jobserver or fall back to number of available 178 cores. 179 + The LTO bytecode can be compressed with the [15]zstd 180 algorithm. The configure script automatically detects zstd 181 support. 182 + Most --param values can now be specified at translation unit 183 granularity. This includes all parameters controlling the 184 inliner and other inter-procedural optimizations. Unlike 185 earlier releases, GCC 10 will ignore parameters controlling 186 optimizations specified at link-time and apply parameters 187 specified at compile-time in the same manner as done for 188 optimization flags. 189 * Profile driven optimization improvements: 190 + Profile maintenance during compilation and hot/cold code 191 partitioning have been improved. 192 + Using [16]-fprofile-values, an instrumented binary can track 193 multiple values (up to 4) for e.g. indirect calls and provide 194 more precise profile information. 195 196 New Languages and Language-Specific Improvements 197 198 * Version 2.6 of the [17]OpenACC specification is now supported in 199 the C, C++ and Fortran compilers. See the [18]implementation status 200 section on the OpenACC wiki page and the [19]run-time library 201 documentation for further information. 202 * GCC 10 adds a number of newly implemented [20]OpenMP 5.0 features 203 on top of the GCC 9 release such as conditional lastprivate clause, 204 scan and loop directives, order(concurrent) and use_device_addr 205 clauses support, if clause on simd construct or partial support for 206 the declare variant directive, getting closer to full support of 207 the OpenMP 5.0 standard. 208 * OpenMP and OpenACC now support [21]offloading to AMD Radeon (GCN) 209 GPUs; supported are the third-generation Fiji (fiji) and the 210 fifth-generation VEGA 10/VEGA 20 (gfx900 or gfx906). 211 212 C family 213 214 * New attributes: 215 + The access function and type attribute has been added to 216 describe how a function accesses objects passed to it by 217 pointer or reference, and to associate such arguments with 218 integer arguments denoting the objects' sizes. The attribute 219 is used to enable the detection of invalid accesses by 220 user-defined functions, such as those diagnosed by 221 -Wstringop-overflow. 222 + The symver attribute can be used to bind symbols to specific 223 version nodes on ELF platforms. This is preferred to using 224 inline assembly with GNU as symver directive because the 225 latter is not compatible with link-time optimizations. 226 * New warnings: 227 + [22]-Wstring-compare, enabled by -Wextra, warns about equality 228 and inequality expressions between zero and the result of a 229 call to either strcmp and strncmp that evaluate to a constant 230 as a result of the length of one argument being greater than 231 the size of the array pointed to by the other. 232 + [23]-Wzero-length-bounds, enabled by -Warray-bounds, warns 233 about accesses to elements of zero-length arrays that might 234 overlap other members of the same object. 235 * Enhancements to existing warnings: 236 + [24]-Warray-bounds detects more out-of-bounds accesses to 237 member arrays as well as accesses to elements of zero-length 238 arrays. 239 + [25]-Wformat-overflow makes full use of string length 240 information computed by the strlen optimization pass. 241 + [26]-Wrestrict detects overlapping accesses to dynamically 242 allocated objects. 243 + [27]-Wreturn-local-addr diagnoses more instances of return 244 statements returning addresses of automatic variables. 245 + [28]-Wstringop-overflow detects more out-of-bounds stores to 246 member arrays including zero-length arrays, dynamically 247 allocated objects and variable length arrays, as well as more 248 instances of reads of unterminated character arrays by string 249 built-in functions. The warning also detects out-of-bounds 250 accesses by calls to user-defined functions declared with the 251 new attribute access. 252 + [29]-Warith-conversion re-enables warnings from -Wconversion, 253 -Wfloat-conversion, and -Wsign-conversion that are now off by 254 default for an expression where the result of an arithmetic 255 operation will not fit in the target type due to promotion, 256 but the operands of the expression do fit in the target type. 257 * Extended characters in identifiers may now be specified directly in 258 the input encoding (UTF-8, by default), in addition to the UCN 259 syntax (\uNNNN or \UNNNNNNNN) that is already supported: 260 261 static const int = 3; 262 int get_nave_pi() { 263 return ; 264 } 265 266 C 267 268 * Several new features from the upcoming C2X revision of the ISO C 269 standard are supported with -std=c2x and -std=gnu2x. Some of these 270 features are also supported as extensions when compiling for older 271 language versions. In addition to the features listed, some 272 features previously supported as extensions and now added to the C 273 standard are enabled by default in C2X mode and not diagnosed with 274 -std=c2x -Wpedantic. 275 + The [[]] attribute syntax is supported, as in C++. Existing 276 attributes can be used with this syntax in forms such as 277 [[gnu::const]]. The standard attributes [[deprecated]], 278 [[fallthrough]] and [[maybe_unused]] are supported. 279 + UTF-8 character constants using the u8'' syntax are supported. 280 + <float.h> defines macros FLT_NORM_MAX, DBL_NORM_MAX and 281 LDBL_NORM_MAX. 282 + When decimal floating-point arithmetic is supported, <float.h> 283 defines macros DEC32_TRUE_MIN, DEC64_TRUE_MIN and 284 DEC128_TRUE_MIN, in addition to the macros that were 285 previously only defined if __STDC_WANT_DEC_FP__ was defined 286 before including <float.h>. 287 + In C2X mode, empty parentheses in a function definition give 288 that function a type with a prototype for subsequent calls; 289 other old-style function definitions are diagnosed by default 290 in C2X mode. 291 + The strftime format checking supports the %OB and %Ob formats. 292 + In C2X mode, -fno-fp-int-builtin-inexact is enabled by 293 default. 294 * GCC now defaults to -fno-common. As a result, global variable 295 accesses are more efficient on various targets. In C, global 296 variables with multiple tentative definitions now result in linker 297 errors. With -fcommon such definitions are silently merged during 298 linking. 299 300 C++ 301 302 * Several C++20 features have been implemented: 303 + Concepts, including P0734R0, P0857R0, P1084R2, P1141R2, 304 P0848R3, P1616R1, P1452R2 305 + P1668R1, Permitting Unevaluated inline-assembly in constexpr 306 Functions 307 + P1161R3, Deprecate a[b,c] 308 + P0848R3, Conditionally Trivial Special Member Functions 309 + P1091R3, Extending structured bindings 310 + P1143R2, Adding the constinit keyword 311 + P1152R4, Deprecating volatile 312 + P0388R4, Permit conversions to arrays of unknown bound 313 + P0784R7, constexpr new 314 + P1301R4, [[nodiscard("with reason")]] 315 + P1814R0, class template argument deduction for alias templates 316 + P1816R0, class template argument deduction for aggregates 317 + P0960R3, Parenthesized initialization of aggregates 318 + P1331R2, Allow trivial default initialization in constexpr 319 contexts 320 + P1327R1, Allowing dynamic_cast and polymorphic typeid in 321 constexpr contexts 322 + P0912R5, Coroutines (requires -fcoroutines) 323 * Several C++ Defect Reports have been resolved, e.g.: 324 + DR 1560, lvalue-to-rvalue conversion in ?: 325 + DR 1813, __is_standard_layout for a class with repeated bases 326 + DR 2094, volatile scalars are trivially copyable, 327 + DR 2096, constraints on literal unions 328 + DR 2413, typename in conversion-function-ids 329 + DR 2352, Similar types and reference binding 330 + DR 1601, Promotion of enumeration with fixed underlying type 331 + DR 330, Qualification conversions and pointers to arrays of 332 pointers 333 + DR 1307, Overload resolution based on size of array 334 initializer-list 335 + DR 1710, Missing template keyword in class-or-decltype 336 * New warnings: 337 + [30]-Wmismatched-tags, disabled by default, warns about 338 declarations of structs, classes, and class templates and 339 their specializations with a class-key that does not match 340 either the definition or the first declaration if no 341 definition is provided. The option is provided to ease 342 portability to Windows-based compilers. 343 + [31]-Wredundant-tags, disabled by default, warns about 344 redundant class-key and enum-key in contexts where the key can 345 be eliminated without causing an syntactic ambiguity. 346 * G++ can now detect modifying constant objects in constexpr 347 evaluation (which is undefined behavior). 348 * G++ no longer emits bogus -Wsign-conversion warnings with explicit 349 casts. 350 * Narrowing is now detected in more contexts (e.g., case values). 351 * Memory consumption of the compiler has been reduced in constexpr 352 evaluation. 353 * The noexcept-specifier is now properly treated as a complete-class 354 context as per [class.mem]. 355 * The attribute deprecated can now be used on namespaces too. 356 * The ABI of passing and returning certain C++ classes by value 357 changed on several targets in GCC 10, including [32]AArch64, 358 [33]ARM, [34]PowerPC ELFv2, [35]S/390 and [36]Itanium. These 359 changes affect classes with a zero-sized subobject (an empty base 360 class, or data member with the [[no_unique_address]] attribute) 361 where all other non-static data members have the same type (this is 362 called a "homogeneous aggregate" in some ABI specifications, or if 363 there is only one such member, a "single element"). In -std=c++17 364 and -std=c++20 modes, classes with an empty base class were not 365 considered to have a single element or to be a homogeneous 366 aggregate, and so could be passed differently (in the wrong 367 registers or at the wrong stack address). This could make code 368 compiled with -std=c++17 and -std=c++14 ABI incompatible. This has 369 been corrected and the empty bases are ignored in those ABI 370 decisions, so functions compiled with -std=c++14 and -std=c++17 are 371 now ABI compatible again. Example: struct empty {}; struct S : 372 empty { float f; }; void f(S);. Similarly, in classes containing 373 non-static data members with empty class types using the C++20 374 [[no_unique_address]] attribute, those members weren't ignored in 375 the ABI argument passing decisions as they should be. Both of these 376 ABI changes are now diagnosed with -Wpsabi. 377 378 Runtime Library (libstdc++) 379 380 * Improved experimental C++2a support, including: 381 + Library concepts in <concepts> and <iterator>. 382 + Constrained algorithms in <ranges>, <algorithm>, and <memory> 383 (thanks to Patrick Palka). 384 + New algorithms shift_left and shift_right (thanks to Patrick 385 Palka). 386 + std::span (thanks to JeanHeyd Meneide). 387 + Three-way comparisons in <compare> and throughout the library. 388 + Constexpr support in <algorithm> and elsewhere (thanks to 389 Edward Smith-Rowland). 390 + <stop_token> and std::jthread (thanks to Thomas Rodgers). 391 + std::atomic_ref and std::atomic<floating point>. 392 + Integer comparison functions (cmp_equal, cmp_less etc.). 393 + std::ssize, std::to_array. 394 + std::construct_at, std::destroy, constexpr std::allocator. 395 + Mathematical constants in <numbers>. 396 * Support for RDSEED in std::random_device. 397 * Reduced header dependencies, leading to faster compilation for some 398 code. 399 * The std::iterator base class of std::istreambuf_iterator was 400 changed in C++98 mode to be consistent with C++11 and later 401 standards. This is expected to have no noticeable effect except in 402 the unlikely case of a class which has potentially overlapping 403 subobjects of type std::istreambuf_iterator<C> and another iterator 404 type with a std::iterator<input_iterator_tag, C, ...> base class. 405 The layout of such a type might change when compiled as C++98. 406 [37]Bug 92285 has more details and concrete examples. 407 408 D 409 410 * Support for static foreach has been implemented. 411 * Aliases can now be created directly from any __traits that return 412 symbols or tuples. Previously, an AliasSeq was necessary in order 413 to alias their return. 414 * It is now possible to detect the language ABI specified for a 415 struct, class, or interface using __traits(getLinkage, ...). 416 * Support for core.math.toPrec intrinsics has been added. These 417 intrinsics guarantee the rounding to specific floating-point 418 precisions at specified points in the code. 419 * Support for pragma(inline) has been implemented. Previously the 420 pragma was recognized, but had no effect on the compilation. 421 * Optional parentheses in asm operands are deprecated and will be 422 removed in a future release. 423 * All content imported files are now included in the make dependency 424 list when compiling with -M. 425 * Compiler recognized attributes provided by the gcc.attribute module 426 will now take effect when applied to function prototypes as well as 427 when applied to full function declarations. 428 * Added a --enable-libphobos-checking configure option to control 429 whether run-time checks are compiled into the D runtime library. 430 * Added a --with-libphobos-druntime-only configure option to indicate 431 whether to build only the core D runtime library, or both the core 432 and standard libraries into libphobos. 433 434 Fortran 435 436 * use_device_addr of version 5.0 of the [38]OpenMP specification is 437 now supported. Note that otherwise OpenMP 4.5 is partially 438 supported in the Fortran compiler; the largest missing item is 439 structure element mapping. 440 * The default buffer size for I/O using unformatted files has been 441 increased to 1048576. The buffer size for can now be set at runtime 442 via the environment variables GFORTRAN_FORMATTED_BUFFER_SIZE and 443 GFORTRAN_UNFORMATTED_BUFFER_SIZE for formatted and unformatted 444 files, respectively. 445 * Mismatches between actual and dummy argument lists in a single file 446 are now rejected with an error. Use the new option 447 -fallow-argument-mismatch to turn these errors into warnings; this 448 option is implied with -std=legacy. -Wargument-mismatch has been 449 removed. 450 * The handling of a BOZ literal constant has been reworked to provide 451 better conformance to the Fortran 2008 and 2018 standards. In these 452 Fortran standards, a BOZ literal constant is a typeless and 453 kindless entity. As a part of the rework, documented and 454 undocumented extensions to the Fortran standard now emit errors 455 during compilation. Some of these extensions are permitted with the 456 -fallow-invalid-boz option, which degrades the error to a warning 457 and the code is compiled as with older gfortran. 458 * At any optimization level except-Os, gfortran now uses inline 459 packing for arguments instead of calling a library routine. If the 460 source contains a large number of arguments that need to be 461 repacked, code size or time for compilation can become excessive. 462 If that is the case, -fno-inline-arg-packing can be used to disable 463 inline argument packing. 464 * Legacy extensions: 465 + For formatted input/output, if the explicit widths after the 466 data-edit descriptors I, F and G have been omitted, default 467 widths are used. 468 + A blank format item at the end of a format specification, i.e. 469 nothing following the final comma, is allowed. Use the option 470 -fdec-blank-format-item; this option is implied with -fdec. 471 + The existing support for AUTOMATIC and STATIC attributes has 472 been extended to allow variables with the AUTOMATIC attribute 473 to be used in EQUIVALENCE statements. Use -fdec-static; this 474 option is implied by -fdec. 475 + Allow character literals in assignments and DATA statements 476 for numeric (INTEGER, REAL, or COMPLEX) or LOGICAL variables. 477 Use the option -fdec-char-conversions; this option is implied 478 with -fdec. 479 + DEC comparisons, i.e. allow Hollerith constants to be used in 480 comparisons with INTEGER, REAL, COMPLEX and CHARACTER 481 expressions. Use the option -fdec. 482 * Character type names in errors and warnings now include len in 483 addition to kind; * is used for assumed length. The kind is omitted 484 if it is the default kind. Examples: CHARACTER(12), CHARACTER(6,4). 485 * CO_BROADCAST now supports derived type variables including objects 486 with allocatable components. In this case, the optional arguments 487 STAT= and ERRMSG= are currently ignored. 488 * The handling of module and submodule names has been reworked to 489 allow the full 63-character length mandated by the standard. 490 Previously symbol names were truncated if the combined length of 491 module, submodule, and function name exceeded 126 characters. This 492 change therefore breaks the ABI, but only for cases where this 126 493 character limit was exceeded. 494 495 Go 496 497 * GCC 10 provides a complete implementation of the Go 1.14.6 user 498 packages. 499 500 libgccjit 501 502 * The libgccjit API gained four new entry points: 503 + [39]gcc_jit_version_major, [40]gcc_jit_version_minor, and 504 [41]gcc_jit_version_patchlevel for programmatically checking 505 the libgccjit version from client code, and 506 + [42]gcc_jit_context_new_bitfield 507 508 New Targets and Target Specific Improvements 509 510 AArch64 & arm 511 512 * The AArch64 and arm ports now support condition flag output 513 constraints in inline assembly, as indicated by the 514 __GCC_ASM_FLAG_OUTPUTS__. On arm this feature is only available for 515 A32 and T32 targets. Please refer to the documentation for more 516 details. 517 518 AArch64 519 520 * There have been several improvements related to the Scalable Vector 521 Extension (SVE): 522 + The SVE ACLE types and intrinsics are now supported. They can 523 be accessed using the header file arm_sve.h. 524 + It is now possible to create fixed-length SVE types using the 525 arm_sve_vector_bits attribute. For example: 526 #if __ARM_FEATURE_SVE_BITS==512 527 typedef svint32_t vec512 __attribute__((arm_sve_vector_bits(512))); 528 typedef svbool_t pred512 __attribute__((arm_sve_vector_bits(512))); 529 #endif 530 + -mlow-precision-div, -mlow-precision-sqrt and 531 -mlow-precision-recip-sqrt now work for SVE. 532 + -msve-vector-bits=128 now generates vector-length-specific 533 code for little-endian targets. It continues to generate 534 vector-length-agnostic code for big-endian targets, just as 535 previous releases did for all targets. 536 + The vectorizer is now able to use extending loads and 537 truncating stores, including gather loads and scatter stores. 538 + The vectorizer now compares the cost of vectorizing with SVE 539 and vectorizing with Advanced SIMD and tries to pick the best 540 one. Previously it would always use SVE if possible. 541 + If a vector loop uses Advanced SIMD rather than SVE, the 542 vectorizer now considers using SVE to vectorize the left-over 543 elements (the scalar tail or epilog). 544 + Besides these specific points, there have been many general 545 improvements to the way that the vectorizer uses SVE. 546 * The -mbranch-protection=pac-ret option now accepts the optional 547 argument +b-key extension to perform return address signing with 548 the B-key instead of the A-key. 549 * The option -moutline-atomics has been added to aid deployment of 550 the Large System Extensions (LSE) on GNU/Linux systems built with a 551 baseline architecture targeting Armv8-A. When the option is 552 specified code is emitted to detect the presence of LSE 553 instructions at runtime and use them for standard atomic 554 operations. For more information please refer to the documentation. 555 * The Transactional Memory Extension is now supported through ACLE 556 intrinsics. It can be enabled through the +tme option extension 557 (for example, -march=armv8.5-a+tme). 558 * A number of features from Armv8.5-A are now supported through ACLE 559 intrinsics. These include: 560 + The random number instructions that can be enabled through the 561 (already present in GCC 9.1) +rng option extension. 562 + Floating-point intrinsics to round to integer instructions 563 from Armv8.5-A when targeting -march=armv8.5-a or later. 564 + Memory Tagging Extension intrinsics enabled through the 565 +memtag option extension. 566 * Similarly, the following Armv8.6-A features are now supported 567 through ACLE intrinsics: 568 + The bfloat16 extension. This extension is enabled 569 automatically when Armv8.6-A is selected (such as by 570 -march=armv8.6-a). It can also be enabled for Armv8.2-A and 571 later using the +bf16 option extension. 572 + The Matrix Multiply extension. This extension is split into 573 three parts, one for each supported data type: 574 o Support for 8-bit integer matrix multiply instructions. 575 This extension is enabled automatically when Armv8.6-A is 576 selected. It can also be enabled for Armv8.2-A and later 577 using the +i8mm option extension. 578 o Support for 32-bit floating-point matrix multiply 579 instructions. This extension can be enabled using the 580 +f32mm option extension, which also has the effect of 581 enabling SVE. 582 o Support for 64-bit floating-point matrix multiply 583 instructions. This extension can be enabled using the 584 +f64mm option extension, which likewise has the effect of 585 enabling SVE. 586 * SVE2 is now supported through ACLE intrinsics and (to a limited 587 extent) through autovectorization. It can be enabled through the 588 +sve2 option extension (for example, -march=armv8.5-a+sve2). 589 Additional extensions can be enabled through +sve2-sm4, +sve2-aes, 590 +sve2-sha3 and +sve2-bitperm. 591 * Support has been added for the following processors (GCC 592 identifiers in parentheses): 593 + Arm Cortex-A77 (cortex-a77). 594 + Arm Cortex-A76AE (cortex-a76ae). 595 + Arm Cortex-A65 (cortex-a65). 596 + Arm Cortex-A65AE (cortex-a65ae). 597 + Arm Cortex-A34 (cortex-a34). 598 + Marvell ThunderX3 (thunderx3t110). 599 The GCC identifiers can be used as arguments to the -mcpu or -mtune 600 options, for example: -mcpu=cortex-a77 or -mtune=cortex-a65ae or as 601 arguments to the equivalent target attributes and pragmas. 602 603 arm 604 605 * Support for the FDPIC ABI has been added. It uses 64-bit function 606 descriptors to represent pointers to functions, and enables code 607 sharing on MMU-less systems. The corresponding target triple is 608 arm-uclinuxfdpiceabi, and the C library is uclibc-ng. 609 * Support has been added for the Arm EABI on NetBSD through the 610 arm*-*-netbsdelf-*eabi* triplet. 611 * The handling of 64-bit integer operations has been significantly 612 reworked and improved leading to improved performance and reduced 613 stack usage when using 64-bit integral data types. The option 614 -mneon-for-64bits is now deprecated and will be removed in a future 615 release. 616 * Support has been added for the following processors (GCC 617 identifiers in parentheses): 618 + Arm Cortex-A77 (cortex-a77). 619 + Arm Cortex-A76AE (cortex-a76ae). 620 + Arm Cortex-M35P (cortex-m35p). 621 + Arm Cortex-M55 (cortex-m55). 622 The GCC identifiers can be used as arguments to the -mcpu or -mtune 623 options, for example: -mcpu=cortex-a77 or -mtune=cortex-m35p. 624 * Support has been extended for the ACLE [43]data-processing 625 intrinsics to include 32-bit SIMD, saturating arithmetic, 16-bit 626 multiplication and other related intrinsics aimed at DSP algorithm 627 optimization. 628 * Support for -mpure-code in Thumb-1 (v6m) has been added: this 629 M-profile feature is no longer restricted to targets with MOVT. For 630 example, -mcpu=cortex-m0 now supports this option. 631 * Support for the [44]Armv8.1-M Mainline Architecture has been added. 632 + Armv8.1-M Mainline can be enabled by using the 633 -march=armv8.1-m.main command-line option. 634 * Support for the [45]MVE beta ACLE intrinsics has been added. These 635 intrinsics can be enabled by including the arm_mve.h header file 636 and passing the +mve or +mve.fp option extensions (for example: 637 -march=armv8.1-m.main+mve). 638 * Support for the Custom Datapath Extension beta ACLE [46]intrinsics 639 has been added. 640 * Support for Armv8.1-M Mainline Security Extensions architecture has 641 been added. The -mcmse option, when used in combination with an 642 Armv8.1-M Mainline architecture (for example: -march=armv8.1-m.main 643 -mcmse), now leads to the generation of improved code sequences 644 when changing security states. 645 646 AMD Radeon (GCN) 647 648 * The code generation and in particular the vectorization support has 649 been much improved. 650 651 ARC 652 653 * The interrupt service routine functions save all used registers, 654 including extension registers and auxiliary registers used by Zero 655 Overhead Loops. 656 * Improve code size by using multiple short instructions instead of a 657 single long mov or ior instruction when its long immediate constant 658 is known. 659 * Fix usage of the accumulator register for ARC600. 660 * Fix issues with uncached attribute. 661 * Remove -mq-class option. 662 * Improve 64-bit integer addition and subtraction operations. 663 664 AVR 665 666 * Support for the XMEGA-like devices 667 668 ATtiny202, ATtiny204, ATtiny402, ATtiny404, ATtiny406, ATtiny804, 669 ATtiny806, ATtiny807, ATtiny1604, ATtiny1606, ATtiny1607, ATmega808, 670 ATmega809, ATmega1608, ATmega1609, ATmega3208, ATmega3209, 671 ATmega4808, ATmega4809 672 has been added. 673 * A new command-line option -nodevicespecs has been added. It allows 674 to provide a custom device-specs file by means of 675 676 avr-gcc -nodevicespecs -specs=my-spec-file <options> 677 and without the need to provide options -B and -mmcu=. See [47]AVR 678 command-line options for details. This feature is also available in 679 GCC 9.3+ and GCC 8.4+. 680 * New command-line options -mdouble=[32,64] and -mlong-double=[32,64] 681 have been added. They allow to choose the size (in bits) of the 682 double and long double types, respectively. Whether or not the 683 mentioned layouts are available, whether the options act as a 684 multilib option, and the default for either option are controlled 685 by the new [48]AVR configure options --with-double= and 686 --with-long-double=. 687 * A new configure option --with-libf7= has been added. It controls to 688 which level avr-libgcc provides 64-bit floating point support by 689 means of [49]Libf7. 690 * A new configure option --with-double-comparison= has been added. 691 It's unlikely you need to set this option by hand. 692 693 IA-32/x86-64 694 695 * Support to expand __builtin_roundeven into the appropriate SSE 4.1 696 instruction has been added. 697 * New ISA extension support for Intel ENQCMD was added to GCC. ENQCMD 698 intrinsics are available via the -menqcmd compiler switch. 699 * GCC now supports the Intel CPU named Cooperlake through 700 -march=cooperlake. The switch enables the AVX512BF16 ISA 701 extensions. 702 * GCC now supports the Intel CPU named Tigerlake through 703 -march=tigerlake. The switch enables the MOVDIRI MOVDIR64B 704 AVX512VP2INTERSECT ISA extensions. 705 706 MIPS 707 708 * The mips*-*-linux* targets now mark object files with appropriate 709 GNU-stack note, facilitating use of non-executable stack hardening 710 on GNU/Linux. The soft-float targets have this feature enabled by 711 default, while for hard-float targets it is required for GCC to be 712 configured with --with-glibc-version=2.31 against glibc 2.31 or 713 later. 714 715 PowerPC / PowerPC64 / RS6000 716 717 * Many vector builtins have been listed as deprecated in the 718 [50]64-Bit ELF V2 ABI Specification for quite a number of years. 719 The vector builtins listed in Tables A.8 through A.10 are now 720 deprecated for GCC 10, and will likely be removed from support in 721 GCC 11. Note that this does not result in any loss of function. 722 These deprecated builtins generally provide somewhat nonsensical 723 argument lists (for example, mixing signed, unsigned, and bool 724 vector arguments arbitrarily), or are duplicate builtins that are 725 inconsistent with the expected naming scheme. We expect that this 726 will be unlikely to affect much if any code, and any required code 727 changes will be trivial. 728 729 PRU 730 731 * A new back end targeting TI PRU I/O processors has been contributed 732 to GCC. 733 734 RISC-V 735 736 * The riscv*-*-* targets now require GNU binutils version 2.30 or 737 later, to support new assembly instructions produced by GCC. 738 739 V850 740 741 * The ABI for V850 nested functions has been changed. Previously the 742 V850 port used %r20 for the static chain pointer, now the port uses 743 %r19. This corrects a long standing latent bug in the v850 port 744 where a call to a nested function would unexpectedly change the 745 value in %r20. 746 747 Operating Systems 748 749 Improvements for plugin authors 750 751 * GCC diagnostics can now have a chain of events associated with 752 them, describing a path through the code that triggers the problem. 753 These can be printed by the diagnostics subsystem in various ways, 754 controlled by the [51]-fdiagnostics-path-format option, or captured 755 in JSON form via [52]-fdiagnostics-format=json. 756 * GCC diagnostics can now be associated with [53]CWE weakness 757 identifiers, which will appear on the standard error stream, and in 758 the JSON output from [54]-fdiagnostics-format=json. 759 760 Other significant improvements 761 762 * To allow inline expansion of both memcpy and memmove, the existing 763 movmem instruction patterns used for non-overlapping memory copies 764 have been renamed to cpymem. The movmem name is now used for 765 overlapping memory moves, consistent with the library functions 766 memcpy and memmove. 767 * For many releases, when GCC emits a warning it prints the option 768 controlling that warning. As of GCC 10, that option text is now a 769 clickable hyperlink for the documentation of that option (assuming 770 a [55]sufficiently capable terminal). This behavior can be 771 controlled via a new [56]-fdiagnostics-urls option (along with 772 various environment variables and heuristics documented with that 773 option). 774 775 GCC 10.1 776 777 This is the [57]list of problem reports (PRs) from GCC's bug tracking 778 system that are known to be fixed in the 10.1 release. This list might 779 not be complete (that is, it is possible that some PRs that have been 780 fixed are not listed here). 781 782 GCC 10.2 783 784 This is the [58]list of problem reports (PRs) from GCC's bug tracking 785 system that are known to be fixed in the 10.2 release. This list might 786 not be complete (that is, it is possible that some PRs that have been 787 fixed are not listed here). 788 789 GCC 10.3 790 791 This is the [59]list of problem reports (PRs) from GCC's bug tracking 792 system that are known to be fixed in the 10.3 release. This list might 793 not be complete (that is, it is possible that some PRs that have been 794 fixed are not listed here). 795 796 Target Specific Changes 797 798 AArch64 799 800 * A bug with the Random Number intrinsics in the arm_acle.h header 801 that resulted in an incorrect status result being returned has been 802 fixed. 803 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 804 options are -mcpu=a64fx and -mtune=a64fx respectively. In 805 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 806 tunes the code for the A64FX. This includes tuning the SVE code, 807 although by default the code is still length-agnostic and so works 808 for all SVE implementations. Adding -msve-vector-bits=512 makes the 809 code specific to 512-bit SVE. 810 811 x86-64 812 813 * GCC 10.3 supports AMD CPUs based on the znver3 core via 814 -march=znver3. 815 816 GCC 10.4 817 818 This is the [60]list of problem reports (PRs) from GCC's bug tracking 819 system that are known to be fixed in the 10.4 release. This list might 820 not be complete (that is, it is possible that some PRs that have been 821 fixed are not listed here). 822 823 Target Specific Changes 824 825 x86-64 826 827 * The x86-64 ABI of passing and returning structures with a 64-bit 828 integer vector changed in GCC 10.1 when MMX is disabled. Disabling 829 MMX no longer changes how they are passed nor returned. This ABI 830 change is now diagnosed with -Wpsabi. 831 832 833 For questions related to the use of GCC, please consult these web 834 pages and the [61]GCC manuals. If that fails, the 835 [62]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 836 web pages and the development of GCC are welcome on our developer 837 list at [63]gcc (a] gcc.gnu.org. All of [64]our lists have public 838 archives. 839 840 Copyright (C) [65]Free Software Foundation, Inc. Verbatim copying and 841 distribution of this entire article is permitted in any medium, 842 provided this notice is preserved. 843 844 These pages are [66]maintained by the GCC team. Last modified 845 2022-06-28[67]. 846 847 References 848 849 1. http://gcc.gnu.org/gcc-10/porting_to.html 850 2. http://gcc.gnu.org/onlinedocs/index.html#current 851 3. http://gcc.gnu.org/gcc-10/changes.html#empty_base 852 4. https://www.mpfr.org/ 853 5. http://gcc.gnu.org/gcc-10/changes.html#iterator_base 854 6. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/cpp/_005f_005fhas_005fbuiltin.html#g_t_005f_005fhas_005fbuiltin 855 7. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fno-allocation-dce 856 8. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-partial-training 857 9. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-reproducible 858 10. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-generate 859 11. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-prefix-path 860 12. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html 861 13. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-finline-functions 862 14. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/lto-dump.html 863 15. https://facebook.github.io/zstd/ 864 16. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-values 865 17. https://www.openacc.org/ 866 18. https://gcc.gnu.org/wiki/OpenACC/Implementation Status#status-10 867 19. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/libgomp/#toc-Enabling-OpenACC-1 868 20. https://www.openmp.org/specifications/ 869 21. https://gcc.gnu.org/wiki/Offloading 870 22. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstring-compare 871 23. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wzero-length-bounds 872 24. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warray-bounds 873 25. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wformat-overflow 874 26. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wrestrict 875 27. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wreturn-local-addr 876 28. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstringop-overflow 877 29. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warith-conversion 878 30. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-tags 879 31. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wredundant-tags 880 32. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94383 881 33. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711 882 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94707 883 35. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94704 884 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94706 885 37. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92285 886 38. https://www.openmp.org/specifications/ 887 39. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_major 888 40. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_minor 889 41. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_patchlevel 890 42. https://gcc.gnu.org/onlinedocs/jit/topics/types.html#c.gcc_jit_context_new_bitfield 891 43. https://developer.arm.com/documentation/101028/0009/Data-processing-intrinsics 892 44. https://developer.arm.com/architectures/cpu-architecture/m-profile 893 45. https://developer.arm.com/architectures/instruction-sets/simd-isas/helium/helium-intrinsics 894 46. https://developer.arm.com/documentation/101028/0010/Custom-Datapath-Extension 895 47. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/AVR-Options.html#index-nodevicespecs 896 48. https://gcc.gnu.org/install/configure.html#avr 897 49. https://gcc.gnu.org/wiki/avr-gcc#Libf7 898 50. https://openpowerfoundation.org/?resource_lib=64-bit-elf-v2-abi-specification-power-architecture 899 51. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-path-format 900 52. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 901 53. https://cwe.mitre.org/ 902 54. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 903 55. https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda 904 56. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-urls 905 57. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.0 906 58. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.2 907 59. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.3 908 60. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.4 909 61. https://gcc.gnu.org/onlinedocs/ 910 62. mailto:gcc-help (a] gcc.gnu.org 911 63. mailto:gcc (a] gcc.gnu.org 912 64. https://gcc.gnu.org/lists.html 913 65. https://www.fsf.org/ 914 66. https://gcc.gnu.org/about.html 915 67. http://validator.w3.org/check/referer 916 ====================================================================== 917 http://gcc.gnu.org/gcc-9/index.html 918 GCC 9 Release Series 919 920 May 27, 2022 921 922 The [1]GNU project and the GCC developers are pleased to announce the 923 release of GCC 9.5. 924 925 This release is a bug-fix release, containing fixes for regressions in 926 GCC 9.4 relative to previous releases of GCC. 927 928 Release History 929 930 GCC 9.5 931 May 27, 2022 ([2]changes, [3]documentation) 932 933 GCC 9.4 934 June 1, 2021 ([4]changes, [5]documentation) 935 936 GCC 9.3 937 Mar 12, 2020 ([6]changes, [7]documentation) 938 939 GCC 9.2 940 Aug 12, 2019 ([8]changes, [9]documentation) 941 942 GCC 9.1 943 May 3, 2019 ([10]changes, [11]documentation) 944 945 References and Acknowledgements 946 947 GCC used to stand for the GNU C Compiler, but since the compiler 948 supports several other languages aside from C, it now stands for the 949 GNU Compiler Collection. 950 951 A list of [12]successful builds is updated as new information becomes 952 available. 953 954 The GCC developers would like to thank the numerous people that have 955 contributed new features, improvements, bug fixes, and other changes as 956 well as test results to GCC. This [13]amazing group of volunteers is 957 what makes GCC successful. 958 959 For additional information about GCC please refer to the [14]GCC 960 project web site or contact the [15]GCC development mailing list. 961 962 To obtain GCC please use [16]our mirror sites or [17]our version 963 control system. 964 965 966 For questions related to the use of GCC, please consult these web 967 pages and the [18]GCC manuals. If that fails, the 968 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 969 web pages and the development of GCC are welcome on our developer 970 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 971 archives. 972 973 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 974 distribution of this entire article is permitted in any medium, 975 provided this notice is preserved. 976 977 These pages are [23]maintained by the GCC team. Last modified 978 2022-05-27[24]. 979 980 References 981 982 1. http://www.gnu.org/ 983 2. http://gcc.gnu.org/gcc-9/changes.html 984 3. http://gcc.gnu.org/onlinedocs/9.5.0/ 985 4. http://gcc.gnu.org/gcc-9/changes.html 986 5. http://gcc.gnu.org/onlinedocs/9.4.0/ 987 6. http://gcc.gnu.org/gcc-9/changes.html 988 7. http://gcc.gnu.org/onlinedocs/9.3.0/ 989 8. http://gcc.gnu.org/gcc-9/changes.html 990 9. http://gcc.gnu.org/onlinedocs/9.2.0/ 991 10. http://gcc.gnu.org/gcc-9/changes.html 992 11. http://gcc.gnu.org/onlinedocs/9.1.0/ 993 12. http://gcc.gnu.org/gcc-9/buildstat.html 994 13. http://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Contributors.html 995 14. http://gcc.gnu.org/index.html 996 15. mailto:gcc (a] gcc.gnu.org 997 16. http://gcc.gnu.org/mirrors.html 998 17. http://gcc.gnu.org/git.html 999 18. https://gcc.gnu.org/onlinedocs/ 1000 19. mailto:gcc-help (a] gcc.gnu.org 1001 20. mailto:gcc (a] gcc.gnu.org 1002 21. https://gcc.gnu.org/lists.html 1003 22. https://www.fsf.org/ 1004 23. https://gcc.gnu.org/about.html 1005 24. http://validator.w3.org/check/referer 1006 ====================================================================== 1007 http://gcc.gnu.org/gcc-9/changes.html 1008 GCC 9 Release Series 1009 Changes, New Features, and Fixes 1010 1011 This page is a "brief" summary of some of the huge number of 1012 improvements in GCC 9. You may also want to check out our [1]Porting to 1013 GCC 9 page and the [2]full GCC documentation. 1014 1015 Caveats 1016 1017 * On Arm targets (arm*-*-*), [3]a bug in the implementation of the 1018 procedure call standard (AAPCS) in the GCC 6, 7 and 8 releases has 1019 been fixed: a structure containing a bit-field based on a 64-bit 1020 integral type and where no other element in a structure required 1021 64-bit alignment could be passed incorrectly to functions. This is 1022 an ABI change. If the option -Wpsabi is enabled (on by default) the 1023 compiler will emit a diagnostic note for code that might be 1024 affected. 1025 * Support for a number of older systems and recently unmaintained or 1026 untested target ports of GCC has been declared obsolete in GCC 9. 1027 Unless there is activity to revive them, the next release of GCC 1028 will have their sources permanently removed. 1029 The following ports for individual systems on particular 1030 architectures have been obsoleted: 1031 + Solaris 10 (*-*-solaris2.10). Details can be found in the 1032 [4]announcement. 1033 + Cell Broadband Engine SPU (spu*-*-*). Details can be found in 1034 the [5]announcement. 1035 * A change to the C++ std::rotate algorithm in GCC 9.1.0 can cause 1036 ABI incompatibilities with object files compiled with other 1037 versions of GCC. If the std::rotate algorithm is called with an 1038 empty range then it might cause a divide-by-zero error (as a SIGFPE 1039 signal) and crash. The change has been reverted for GCC 9.2.0 and 1040 future releases. For more details see [6]Bug 90920. The problem can 1041 be avoided by recompiling any objects that might call std::rotate 1042 with an empty range, so that the GCC 9.1.0 definition of 1043 std::rotate is not used. 1044 * The automatic template instantiation at link time ([7]-frepo) has 1045 been deprecated and will be removed in a future release. 1046 * The --with-default-libstdcxx-abi=gcc4-compatible configure option 1047 is broken in the 9.1 and 9.2 releases, producing a shared library 1048 with missing symbols (see [8]Bug 90361). As a workaround, configure 1049 without that option and build GCC as normal, then edit the 1050 installed <bits/c++config.h> headers to define the 1051 _GLIBCXX_USE_CXX11_ABI macro to 0. 1052 1053 General Improvements 1054 1055 The following GCC command line options have been introduced or 1056 improved. 1057 * All command line options that take a byte-size argument accept 1058 64-bit integers as well as standard SI and IEC suffixes such as kb 1059 and KiB, MB and MiB, or GB and GiB denoting the corresponding 1060 multiples of bytes. See [9]Invoking GCC for more. 1061 * A new option, 1062 [10]-flive-patching=[inline-only-static|inline-clone], has been 1063 introduced to provide a safe compilation for live-patching. At the 1064 same time, provides multiple-level control on the enabled IPA 1065 optimizations. See the user guide for more details about the 1066 option. 1067 * A new option, --completion, has been added to provide more fine 1068 option completion in a shell. It is intended to be used by 1069 Bash-completion. 1070 * GCC's diagnostics now print source code with a left margin showing 1071 line numbers, configurable with 1072 [11]-fno-diagnostics-show-line-numbers. 1073 GCC's diagnostics can also now label regions of the source code to 1074 show pertinent information, such as the types within an expression. 1075 $ g++ t.cc 1076 t.cc: In function 'int test(const shape&, const shape&)': 1077 t.cc:15:4: error: no match for 'operator+' (operand types are 'boxed_value<doubl 1078 e>' and 'boxed_value<double>') 1079 14 | return (width(s1) * height(s1) 1080 | ~~~~~~~~~~~~~~~~~~~~~~ 1081 | | 1082 | boxed_value<[...]> 1083 15 | + width(s2) * height(s2)); 1084 | ^ ~~~~~~~~~~~~~~~~~~~~~~ 1085 | | 1086 | boxed_value<[...]> 1087 1088 These labels can be disabled via [12]-fno-diagnostics-show-labels. 1089 * A new option [13]-fdiagnostics-format=json has been introduced for 1090 emitting diagnostics in a machine-readable format. 1091 * The alignment-related options [14]-falign-functions, 1092 [15]-falign-labels, [16]-falign-loops, and [17]-falign-jumps 1093 received support for a secondary alignment (e.g. 1094 -falign-loops=n:m:n2:m2). 1095 * New pair of profiling options ([18]-fprofile-filter-files and 1096 [19]-fprofile-exclude-files) has been added. The options help to 1097 filter which source files are instrumented. 1098 * AddressSanitizer generates more compact redzones for automatic 1099 variables. That helps to reduce memory footprint of a sanitized 1100 binary. 1101 * Numerous improvements have been made to the output of 1102 [20]-fopt-info. 1103 Messages are now prefixed with optimized, missed, or note, rather 1104 than the old behavior of all being prefixed with note. 1105 The output from -fopt-info can now contain information on inlining 1106 decisions: 1107 $ g++ -c inline.cc -O2 -fopt-info-inline-all 1108 inline.cc:24:11: note: Considering inline candidate void foreach(T, T, void (*)( 1109 E)) [with T = char**; E = char*]/2. 1110 inline.cc:24:11: optimized: Inlining void foreach(T, T, void (*)(E)) [with T = 1111 char**; E = char*]/2 into int main(int, char**)/1. 1112 inline.cc:19:12: missed: not inlinable: void inline_me(char*)/0 -> int std::pu 1113 ts(const char*)/3, function body not available 1114 inline.cc:13:8: optimized: Inlined void inline_me(char*)/4 into int main(int, c 1115 har**)/1 which now has time 127.363637 and size 11, net change of +0. 1116 Unit growth for small function inlining: 16->16 (0%) 1117 1118 Inlined 2 calls, eliminated 1 functions 1119 1120 1121 The output from the vectorizer has been rationalized so that failed 1122 attempts to vectorize a loop are displayed in the form 1123 [LOOP-LOCATION]: couldn't vectorize this loop 1124 [PROBLEM-LOCATION]: because of [REASON] 1125 1126 rather than an exhaustive log of all decisions made by the 1127 vectorizer. For example: 1128 $ gcc -c v.c -O3 -fopt-info-all-vec 1129 v.c:7:3: missed: couldn't vectorize loop 1130 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 1131 mory"); 1132 v.c:3:6: note: vectorized 0 loops in function. 1133 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 1134 mory"); 1135 1136 The old behavior can be obtained via a new -internals suboption of 1137 -fopt-info. 1138 * A new option, [21]-fsave-optimization-record has been added, which 1139 writes a SRCFILE.opt-record.json.gz file describing the 1140 optimization decisions made by GCC. This is similar to the output 1141 of -fopt-info, but with additional metadata such as the inlining 1142 chain, and profile information (if available). 1143 * Inter-procedural propagation of stack alignment can now be 1144 controlled by [22]-fipa-stack-alignment. 1145 * Propagation of addressability, readonly and writeonly flags on 1146 static variables can now be controlled by 1147 [23]-fipa-reference-addressable. 1148 1149 The following built-in functions have been introduced. 1150 * [24]__builtin_expect_with_probability to provide branch prediction 1151 probability hints to the optimizer. 1152 * [25]__builtin_has_attribute determines whether a function, type, or 1153 variable has been declared with some attribute. 1154 * [26]__builtin_speculation_safe_value can be used to help mitigate 1155 against unsafe speculative execution. 1156 1157 The following attributes have been introduced. 1158 * The [27]copy function attribute has been added. The attribute can 1159 also be applied to type definitions and to variable declarations. 1160 1161 A large number of improvements to code generation have been made, 1162 including but not limited to the following. 1163 * Switch expansion has been improved by using a different strategy 1164 (jump table, bit test, decision tree) for a subset of switch cases. 1165 * A linear function expression defined as a switch statement can be 1166 transformed by [28]-ftree-switch-conversion. For example: 1167 1168 int 1169 foo (int how) 1170 { 1171 switch (how) { 1172 case 2: how = 205; break; 1173 case 3: how = 305; break; 1174 case 4: how = 405; break; 1175 case 5: how = 505; break; 1176 case 6: how = 605; break; 1177 } 1178 return how; 1179 } 1180 1181 can be transformed into 100 * how + 5 (for values defined in the 1182 switch statement). 1183 * Inter-procedural optimization improvements: 1184 + Inliner defaults was tuned to better suits modern C++ 1185 codebases especially when built with link time optimizations. 1186 New parameters max-inline-insns-small, max-inline-insns-size, 1187 uninlined-function-insns, uninlined-function-time, 1188 uninlined-thunk-insns, and uninlined-thunk-time were added. 1189 + Hot/cold partitioning is now more precise and aggressive. 1190 + Improved scalability for very large translation units 1191 (especially when link-time optimizing large programs). 1192 * Profile driven optimization improvements: 1193 + [29]-fprofile-use now enables [30]-fversion-loops-for-strides, 1194 [31]-floop-interchange, [32]-floop-unroll-and-jam, 1195 [33]-ftree-loop-distribution. 1196 + Streaming of counter histograms was removed. This reduces the 1197 size of profile files. Histogram is computed on the fly with 1198 link-time optimization. Parameter hot-bb-count-ws-permille was 1199 reduced from 999 to 990 to account for more precise 1200 histograms. 1201 * Link-time optimization improvements: 1202 + Types are now simplified prior streaming resulting in 1203 significant reductions of the LTO object files, link-time 1204 memory use, and improvements of link-time parallelism. 1205 + Default number of partitions (--param lto-partitions) was 1206 increased from 32 to 128 enabling effective use of CPUs with 1207 more than 32 hyperthreads. --param 1208 lto-max-streaming-parallelism can now be used to control 1209 number of streaming processes. 1210 + Warnings on C++ One Decl Rule violations (-Wodr) are now more 1211 informative and produce fewer redundant results. 1212 Overall compile time of Firefox 66 and LibreOffice 6.2.3 on an 1213 8-core machine was reduced by about 5% compared to GCC 8.3, and the 1214 size of LTO object files by 7%. LTO link-time improves by 11% on an 1215 8-core machine and scales significantly better for more parallel 1216 build environments. The serial stage of the link-time optimization 1217 is 28% faster consuming 20% less memory. The parallel stage now 1218 scales to up to 128 partitions rather than 32 and reduces memory 1219 use for every worker by 30%. 1220 1221 The following improvements to the gcov command-line utility have been 1222 made. 1223 * The gcov tool received a new option [34]--use-hotness-colors (-q) 1224 that can provide perf-like coloring of hot functions. 1225 * The gcov tool has changed its intermediate format to a new JSON 1226 format. 1227 1228 New Languages and Language specific improvements 1229 1230 [35]OpenACC support in C, C++, and Fortran continues to be maintained 1231 and improved. Most of the OpenACC 2.5 specification is implemented. See 1232 the [36]implementation status section on the OpenACC wiki page for 1233 further information. 1234 1235 C family 1236 1237 * Version 5.0 of the [37]OpenMP specification is now partially 1238 supported in the C and C++ compilers. For details which features of 1239 OpenMP 5.0 are and which are not supported in the GCC 9 release see 1240 [38]this mail. 1241 * New extensions: 1242 + [39]__builtin_convertvector built-in for vector conversions 1243 has been added. 1244 * New warnings: 1245 + [40]-Waddress-of-packed-member, enabled by default, warns 1246 about an unaligned pointer value from the address of a packed 1247 member of a struct or union. 1248 * Enhancements to existing warnings: 1249 + [41]-Warray-bounds detects more instances of out-of-bounds 1250 indices. 1251 + [42]-Wattribute-alias also detects attribute mismatches 1252 between alias declarations and their targets, in addition to 1253 mismatches between their types. 1254 + [43]-Wformat-overflow and [44]-Wformat-truncation have been 1255 extended to all formatted input/output functions (where 1256 applicable) and enhanced to detect a subset of instances of 1257 reading past the end of unterminated constant character arrays 1258 in %s directives. 1259 + [45]-Wmissing-attributes detects instances of missing function 1260 attributes on declarations of aliases and weak references. 1261 + [46]-Wstringop-truncation also detects a subset of instances 1262 of reading past the end of unterminated constant character 1263 arrays, 1264 * If a macro is used with the wrong argument count, the C and C++ 1265 front ends now show the definition of that macro via a note. 1266 * The spelling corrector now considers transposed letters, and the 1267 threshold for similarity has been tightened, to avoid nonsensical 1268 suggestions. 1269 1270 C 1271 1272 * There is now experimental support for -std=c2x, to select support 1273 for the upcoming C2X revision of the ISO C standard. This standard 1274 is in the early stages of development and the only feature 1275 supported in GCC 9 is _Static_assert with a single argument 1276 (support for _Static_assert with two arguments was added in C11 and 1277 GCC 4.6). There are also new options -std=gnu2x, for C2X with GNU 1278 extensions, and -Wc11-c2x-compat, to warn for uses of features 1279 added in C2X (such warnings are also enabled by use of -Wpedantic 1280 if not using -std=c2x or -std=gnu2x). 1281 * New warnings: 1282 + [47]-Wabsolute-value warns for calls to standard functions 1283 that compute the absolute value of an argument when a more 1284 appropriate standard function is available. For example, 1285 calling abs(3.14) triggers the warning because the appropriate 1286 function to call to compute the absolute value of a double 1287 argument is fabs. The option also triggers warnings when the 1288 argument in a call to such a function has an unsigned type. 1289 This warning can be suppressed with an explicit type cast and 1290 it is also enabled by -Wextra. 1291 1292 C++ 1293 1294 * New warnings: 1295 + [48]-Wdeprecated-copy, implied by -Wextra, warns about the 1296 C++11 deprecation of implicitly declared copy constructor and 1297 assignment operator if one of them is user-provided. 1298 -Wdeprecated-copy-dtor also warns if the destructor is 1299 user-provided, as specified in C++11. 1300 + [49]-Winit-list-lifetime, on by default, warns about uses of 1301 std::initializer_list that are likely to result in a dangling 1302 pointer, such as returning or assigning from a temporary list. 1303 + [50]-Wredundant-move, implied by -Wextra, warns about 1304 redundant calls to std::move. 1305 + [51]-Wpessimizing-move, implied by -Wall, warns when a call to 1306 std::move prevents copy elision. 1307 + [52]-Wclass-conversion, on by default, warns when a conversion 1308 function will never be called due to the type it converts to. 1309 * The C++ front end has experimental support for some of the upcoming 1310 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 1311 including range-based for statements with initializer, default 1312 constructible and assignable stateless lambdas, lambdas in 1313 unevaluated contexts, language support for empty data members, 1314 allowing pack expansion in lambda init-capture, likely and unlikely 1315 attributes, class types in non-type template parameters, allowing 1316 virtual function calls in constant expressions, explicit(bool), 1317 std::is_constant_evaluated, nested inline namespaces, etc. For a 1318 full list of new features, see [53]the C++ status page. 1319 * The C++ front end now preserves source locations for literals, 1320 id-expression, and mem-initializer for longer. For example it is 1321 now able to pin-point the pertinent locations for bad 1322 initializations such as these 1323 $ g++ -c bad-inits.cc 1324 bad-inits.cc:10:14: error: cannot convert 'json' to 'int' in initialization 1325 10 | { 3, json::object }, 1326 | ~~~~~~^~~~~~ 1327 | | 1328 | json 1329 bad-inits.cc:14:31: error: initializer-string for array of chars is too long [-f 1330 permissive] 1331 14 | char buffers[3][5] = { "red", "green", "blue" }; 1332 | ^~~~~~~ 1333 bad-inits.cc: In constructor 'X::X()': 1334 bad-inits.cc:17:13: error: invalid conversion from 'int' to 'void*' [-fpermissiv 1335 e] 1336 17 | X() : one(42), two(42), three(42) 1337 | ^~ 1338 | | 1339 | int 1340 1341 rather than emitting the error at the final closing parenthesis or 1342 brace. 1343 * Error-reporting of overload resolution has been special-cased to 1344 make the case of a single failed candidate easier to read. For 1345 example: 1346 $ g++ param-type-mismatch.cc 1347 param-type-mismatch.cc: In function 'int test(int, const char*, float)': 1348 param-type-mismatch.cc:8:32: error: cannot convert 'const char*' to 'const char* 1349 *' 1350 8 | return foo::member_1 (first, second, third); 1351 | ^~~~~~ 1352 | | 1353 | const char* 1354 param-type-mismatch.cc:3:46: note: initializing argument 2 of 'static int foo: 1355 :member_1(int, const char**, float)' 1356 3 | static int member_1 (int one, const char **two, float three); 1357 | ~~~~~~~~~~~~~^~~ 1358 1359 highlights both the problematic argument, and the parameter that it 1360 can't be converted to. 1361 * Diagnostics involving binary operators now use color to distinguish 1362 the two operands, and label them separately (as per the example of 1363 source labelling above). 1364 * Diagnostics involving function calls now highlight the pertinent 1365 parameter of the declaration in more places. 1366 $ g++ bad-conversion.cc 1367 bad-conversion.cc: In function 'void caller()': 1368 bad-conversion.cc:9:14: error: cannot convert 'bool' to 'void*' 1369 9 | callee (0, false, 2); 1370 | ^~~~~ 1371 | | 1372 | bool 1373 bad-conversion.cc:3:19: note: initializing argument 2 of 'void callee(int, voi 1374 d*, int)' 1375 3 | void callee (int, void *, int) 1376 | ^~~~~~ 1377 1378 * The C++ front end's implementation of [54]-Wformat now shows 1379 precise locations within string literals, and underlines the 1380 pertinent arguments at bogus call sites (the C front end has been 1381 doing this since GCC 7). For example: 1382 $ g++ -c bad-printf.cc -Wall 1383 bad-printf.cc: In function 'void print_field(const char*, float, long int, long 1384 int)': 1385 bad-printf.cc:6:17: warning: field width specifier '*' expects argument of type 1386 'int', but argument 3 has type 'long int' [-Wformat=] 1387 6 | printf ("%s: %*ld ", fieldname, column - width, value); 1388 | ~^~~ ~~~~~~~~~~~~~~ 1389 | | | 1390 | int long int 1391 bad-printf.cc:6:19: warning: format '%ld' expects argument of type 'long int', b 1392 ut argument 4 has type 'double' [-Wformat=] 1393 6 | printf ("%s: %*ld ", fieldname, column - width, value); 1394 | ~~~^ ~~~~~ 1395 | | | 1396 | long int double 1397 | %*f 1398 1399 * The C++ front end has gained new fix-it hints for forgetting the 1400 return *this; needed by various C++ operators: 1401 $ g++ -c operator.cc 1402 operator.cc: In member function 'boxed_ptr& boxed_ptr::operator=(const boxed_ptr 1403 &)': 1404 operator.cc:7:3: warning: no return statement in function returning non-void [-W 1405 return-type] 1406 6 | m_ptr = other.m_ptr; 1407 +++ |+ return *this; 1408 7 | } 1409 | ^ 1410 1411 for when the compiler needs a typename: 1412 $ g++ -c template.cc 1413 template.cc:3:3: error: need 'typename' before 'Traits::type' because 'Traits' i 1414 s a dependent scope 1415 3 | Traits::type type; 1416 | ^~~~~~ 1417 | typename 1418 1419 when trying to use an accessor member as if it were a data member: 1420 $ g++ -c fncall.cc 1421 fncall.cc: In function 'void hangman(const mystring&)': 1422 fncall.cc:12:11: error: invalid use of member function 'int mystring::get_length 1423 () const' (did you forget the '()' ?) 1424 12 | if (str.get_length > 0) 1425 | ~~~~^~~~~~~~~~ 1426 | () 1427 1428 for C++11's scoped enums: 1429 $ g++ -c enums.cc 1430 enums.cc: In function 'void json::test(const json::value&)': 1431 enums.cc:12:26: error: 'STRING' was not declared in this scope; did you mean 'js 1432 on::kind::STRING'? 1433 12 | if (v.get_kind () == STRING) 1434 | ^~~~~~ 1435 | json::kind::STRING 1436 enums.cc:3:44: note: 'json::kind::STRING' declared here 1437 3 | enum class kind { OBJECT, ARRAY, NUMBER, STRING, TRUE, FALSE, NULL_ }; 1438 | ^~~~~~ 1439 1440 and a tweak to integrate the suggestions about misspelled members 1441 with that for accessors: 1442 $ g++ -c accessor-fixit.cc 1443 accessor-fixit.cc: In function 'int test(t*)': 1444 accessor-fixit.cc:17:15: error: 'class t' has no member named 'ratio'; did you m 1445 ean 'int t::m_ratio'? (accessible via 'int t::get_ratio() const') 1446 17 | return ptr->ratio; 1447 | ^~~~~ 1448 | get_ratio() 1449 1450 In addition, various diagnostics in the C++ front-end have been 1451 streamlined by consolidating the suggestion into the initial error, 1452 rather than emitting a follow-up note: 1453 $ g++ typo.cc 1454 typo.cc:5:13: error: 'BUFSIZE' was not declared in this scope; did you mean 'BUF 1455 _SIZE'? 1456 5 | uint8_t buf[BUFSIZE]; 1457 | ^~~~~~~ 1458 | BUF_SIZE 1459 1460 Runtime Library (libstdc++) 1461 1462 * Improved support for C++17, including: 1463 + The C++17 implementation is no longer experimental. 1464 + Parallel algorithms and <execution> (requires [55]Thread 1465 Building Blocks 2018 or newer). 1466 + <memory_resource>. 1467 + Using the types and functions in <filesystem> does not require 1468 linking with -lstdc++fs now. 1469 * Improved experimental support for C++2a, including: 1470 + Type traits std::remove_cvref, std::unwrap_reference, 1471 std::unwrap_decay_ref, std::is_nothrow_convertible, and 1472 std::type_identity. 1473 + Headers <bit> and <version>. 1474 + Uniform container erasure (std::erase_if). 1475 + contains member of maps and sets. 1476 + String prefix and suffix checking (starts_with, ends_with). 1477 + Functions std::midpoint and std::lerp for interpolation. 1478 + std::bind_front. 1479 + std::visit<R>. 1480 + std::assume_aligned. 1481 + Uses-allocator construction utilities. 1482 + std::pmr::polymorphic_allocator<std::byte>. 1483 + Library support for char8_t type. 1484 + Destroying delete. 1485 + std::is_constant_evaluated() function. 1486 * Support for opening file streams with wide character paths on 1487 Windows 1488 * Incomplete support for the C++17 Filesystem library and the 1489 Filesystem TS on Windows. 1490 * Incomplete, experimental support for the Networking TS. 1491 1492 D 1493 1494 * Support for the D programming language has been added to GCC, 1495 implementing version 2.076 of the language and run-time library. 1496 1497 Fortran 1498 1499 * Asynchronous I/O is now fully supported. The program needs to be 1500 linked against the pthreads library to use it, otherwise the I/O is 1501 done synchronously. For systems which do not support POSIX 1502 condition variables, such as AIX, all I/O is still done 1503 synchronously. 1504 * The BACK argument for MINLOC and MAXLOC has been implemented. 1505 * The FINDLOC intrinsic function has been implemented. 1506 * The IS_CONTIGUOUS intrinsic function has been implemented. 1507 * Direct access to the real and imaginary parts of a complex variable 1508 via c%re and c%im has been implemented. 1509 * Type parameter inquiry via str%len and a%kind has been implemented. 1510 * C descriptors and the ISO_Fortran_binding.h source file have been 1511 implemented. 1512 * The MAX and MIN intrinsics are no longer guaranteed to return any 1513 particular value in case one of the arguments is a NaN. Note that 1514 this conforms to the Fortran standard and to what other Fortran 1515 compilers do. If there is a need to handle that case in some 1516 specific way, one needs to explicitly check for NaN's before 1517 calling MAX or MIN, e.g. by using the IEEE_IS_NAN function from the 1518 intrinsic module IEEE_ARITHMETIC. 1519 * A new command-line option [56]-fdec-include, set also by the 1520 [57]-fdec option, has been added to increase compatibility with 1521 legacy code. With this option, an INCLUDE directive is also parsed 1522 as a statement, which allows the directive to be spread across 1523 multiple source lines with line continuations. 1524 * A new [58]BUILTIN directive, has been added. The purpose of the 1525 directive is to provide an API between the GCC compiler and the GNU 1526 C Library which would define vector implementations of math 1527 routines. 1528 1529 Go 1530 1531 * GCC 9 provides a complete implementation of the Go 1.12.2 user 1532 packages. 1533 1534 libgccjit 1535 1536 * The libgccjit API gained a new entry point: 1537 [59]gcc_jit_context_add_driver_option. 1538 1539 New Targets and Target Specific Improvements 1540 1541 AArch64 & Arm 1542 1543 * Support has been added for the following processors (GCC 1544 identifiers in parentheses): 1545 + Arm Cortex-A76 (cortex-a76). 1546 + Arm Cortex-A55/Cortex-A76 DynamIQ big.LITTLE 1547 (cortex-a76.cortex-a55). 1548 + Arm Neoverse N1 (neoverse-n1). 1549 The GCC identifiers can be used as arguments to the -mcpu or -mtune 1550 options, for example: -mcpu=cortex-a76 or 1551 -mtune=cortex-a76.cortex-a55 or as arguments to the equivalent 1552 target attributes and pragmas. 1553 * The Armv8.3-A complex number instructions are now supported via 1554 intrinsics when the option -march=armv8.3-a or equivalent is 1555 specified. For the half-precision floating-point variants of these 1556 instructions use the architecture extension flag +fp16, e.g. 1557 -march=armv8.3-a+fp16. 1558 The intrinsics are defined by the ACLE specification. 1559 * The Armv8.5-A architecture is now supported through the 1560 -march=armv8.5-a option. 1561 * The Armv8.5-A architecture also adds some security features that 1562 are optional to all older architecture versions. These are now 1563 supported and only affect the assembler. 1564 + Speculation Barrier instruction through the -march=armv8-a+sb 1565 option. 1566 + Execution and Data Prediction Restriction instructions through 1567 the -march=armv8-a+predres option. 1568 + Speculative Store Bypass Safe instruction through the 1569 -march=armv8-a+ssbs option. This does not require a compiler 1570 option for Arm and thus -march=armv8-a+ssbs is an 1571 AArch64-specific option. 1572 1573 AArch64 specific 1574 1575 * Support has been added for the Arm Neoverse E1 processor 1576 (-mcpu=neoverse-e1). 1577 * The AArch64 port now has support for stack clash protection using 1578 the [60]-fstack-clash-protection option. The probing interval/guard 1579 size can be set by using --param 1580 stack-clash-protection-guard-size=12|16. The value of this 1581 parameter must be in bytes represented as a power of two. The two 1582 supported values for this parameter are 12 (for a 4KiB size, 2^12) 1583 and 16 (for a 64KiB size, 2^16). The default value is 16 (64Kb) and 1584 can be changed at configure time using the flag 1585 --with-stack-clash-protection-guard-size=12|16. 1586 * The option -msign-return-address= has been deprecated. This has 1587 been replaced by the new -mbranch-protection= option. This new 1588 option can now be used to enable the return address signing as well 1589 as the new Branch Target Identification feature of Armv8.5-A 1590 architecture. For more information on the arguments accepted by 1591 this option, please refer to [61]AArch64-Options. 1592 * The following optional extensions to Armv8.5-A architecture are now 1593 supported and only affect the assembler. 1594 + Random Number Generation instructions through the 1595 -march=armv8.5-a+rng option. 1596 + Memory Tagging Extension through the -march=armv8.5-a+memtag 1597 option. 1598 1599 Arm specific 1600 1601 * Support for the deprecated Armv2 and Armv3 architectures and their 1602 variants has been removed. Their corresponding -march values and 1603 the -mcpu options that used these architectures have been removed. 1604 * Support for the Armv5 and Armv5E architectures (which have no known 1605 implementations) has been removed. Note that Armv5T, Armv5TE and 1606 Armv5TEJ architectures remain supported. 1607 * Corrected FPU configurations for Cortex-R7 and Cortex-R8 when using 1608 their respective -mcpu options. 1609 1610 AMD GCN 1611 1612 * A new back end targeting AMD GCN GPUs has been contributed to GCC. 1613 The implementation is currently limited to compiling 1614 single-threaded, stand-alone programs. Future versions will add 1615 support for offloading multi-threaded kernels via OpenMP and 1616 OpenACC. The following devices are supported (GCC identifiers in 1617 parentheses): 1618 + Fiji (fiji). 1619 + Vega 10 (gfx900). 1620 1621 ARC 1622 1623 * LRA is now on by default for the ARC target. This can be controlled 1624 by -mlra. 1625 * Add support for frame code-density and branch-and-index 1626 instructions. 1627 1628 C-SKY 1629 1630 * A new back end targeting C-SKY V2 processors has been contributed 1631 to GCC. 1632 1633 IA-32/x86-64 1634 1635 * Support of Intel MPX (Memory Protection Extensions) has been 1636 removed. 1637 * New ISA extension support for Intel PTWRITE was added to GCC. 1638 PTWRITE intrinsics are available via the -mptwrite compiler switch. 1639 * GCC now supports the Intel CPU named Cascade Lake with AVX512 1640 extensions through -march=cascadelake. The switch enables the 1641 following ISA extensions: AVX512F, AVX512VL, AVX512CD, AVX512BW, 1642 AVX512DQ, AVX512VNNI. 1643 1644 OpenRISC 1645 1646 * A new back end targeting OpenRISC processors has been contributed 1647 to GCC. 1648 1649 S/390, System z, IBM z Systems 1650 1651 * Support for the arch13 architecture has been added. When using the 1652 -march=arch13 option, the compiler will generate code making use of 1653 the new instructions introduced with the vector enhancement 1654 facility 2 and the miscellaneous instruction extension facility 2. 1655 The -mtune=arch13 option enables arch13 specific instruction 1656 scheduling without making use of new instructions. 1657 * Builtins for the new vector instructions have been added and can be 1658 enabled using the -mzvector option. 1659 * Support for ESA architecture machines g5 and g6 is deprecated since 1660 GCC 6.1.0 and has been removed now. 1661 * When compiling with -march=z14 or higher GCC emits alignments hints 1662 on the vector load/store instructions (8 or 16 byte). 1663 * Functions now have a default alignment of 16 bytes. This helps with 1664 branch prediction effects. 1665 * -mfentry is now supported. As well as the mcount mechanism the 1666 __fentry__ is called before the function prologue. However, since 1667 just a single instruction is required to call __fentry__ the call 1668 sequence imposes a smaller overhead than mcount (4 instructions). 1669 The produced code is compatible only with newer glibc versions, 1670 which provide the __fentry__ symbol and do not clobber r0 when 1671 resolving lazily bound functions. -mfentry is only supported when 1672 generating 64 bit code and does not work with nested C functions. 1673 * The -mnop-mcount option can be used to emit NOP instructions 1674 instead of an mcount or fentry call stub. 1675 * With the -mrecord-mcount option a __mcount_loc section is generated 1676 containing pointers to each profiling call stub. This is useful for 1677 automatically patching in and out calls. 1678 1679 Operating Systems 1680 1681 Solaris 1682 1683 * g++ now unconditionally enables large file support when compiling 1684 32-bit code. 1685 * Support for the AddressSanitizer and UndefinedBehaviorSanitizer has 1686 been merged from LLVM. For the moment, this only works for 32-bit 1687 code on both SPARC and x86. 1688 * An initial port of the D runtime library has been completed on 1689 Solaris 11/x86. It requires the use of GNU as. Solaris 11/SPARC 1690 support is still work-in-progress. 1691 1692 Windows 1693 1694 * A C++ Microsoft ABI bitfield layout bug, [62]PR87137 has been 1695 fixed. A non-field declaration could cause the current bitfield 1696 allocation unit to be completed, incorrectly placing a following 1697 bitfield into a new allocation unit. The Microsoft ABI is selected 1698 for: 1699 + Mingw targets 1700 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 1701 option is specified, or __attribute__((ms_struct)) is used 1702 + SuperH targets when the -mhitachi option is specified, or 1703 __attribute__((renesas)) is used 1704 1705 Improvements for plugin authors 1706 1707 * GCC's diagnostic subsystem now has a way to logically group 1708 together related diagnostics, auto_diagnostic_group. Such 1709 diagnostics will be nested by the output of 1710 [63]-fdiagnostics-format=json. 1711 * GCC now has a set of [64]user experience guidelines for GCC, with 1712 information and advice on implementing new diagnostics. 1713 1714 Other significant improvements 1715 1716 * GCC's internal "selftest" suite now runs for C++ as well as C (in 1717 debug builds of the compiler). 1718 1719 GCC 9.1 1720 1721 This is the [65]list of problem reports (PRs) from GCC's bug tracking 1722 system that are known to be fixed in the 9.1 release. This list might 1723 not be complete (that is, it is possible that some PRs that have been 1724 fixed are not listed here). 1725 1726 GCC 9.2 1727 1728 This is the [66]list of problem reports (PRs) from GCC's bug tracking 1729 system that are known to be fixed in the 9.2 release. This list might 1730 not be complete (that is, it is possible that some PRs that have been 1731 fixed are not listed here). 1732 1733 GCC 9.3 1734 1735 This is the [67]list of problem reports (PRs) from GCC's bug tracking 1736 system that are known to be fixed in the 9.3 release. This list might 1737 not be complete (that is, it is possible that some PRs that have been 1738 fixed are not listed here). 1739 1740 GCC 9.4 1741 1742 This is the [68]list of problem reports (PRs) from GCC's bug tracking 1743 system that are known to be fixed in the 9.4 release. This list might 1744 not be complete (that is, it is possible that some PRs that have been 1745 fixed are not listed here). 1746 1747 Target Specific Changes 1748 1749 AArch64 1750 1751 * The option -moutline-atomics has been added to aid deployment of 1752 the Large System Extensions (LSE) on GNU/Linux systems built with a 1753 baseline architecture targeting Armv8-A. When the option is 1754 specified code is emitted to detect the presence of LSE 1755 instructions at run time and use them for standard atomic 1756 operations. For more information please refer to the documentation. 1757 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 1758 options are -mcpu=a64fx and -mtune=a64fx respectively. In 1759 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 1760 tunes the code for the A64FX. This includes tuning the SVE code, 1761 although by default the code is still length-agnostic and so works 1762 for all SVE implementations. Adding -msve-vector-bits=512 makes the 1763 code specific to 512-bit SVE. 1764 1765 GCC 9.5 1766 1767 This is the [69]list of problem reports (PRs) from GCC's bug tracking 1768 system that are known to be fixed in the 9.5 release. This list might 1769 not be complete (that is, it is possible that some PRs that have been 1770 fixed are not listed here). 1771 1772 1773 For questions related to the use of GCC, please consult these web 1774 pages and the [70]GCC manuals. If that fails, the 1775 [71]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1776 web pages and the development of GCC are welcome on our developer 1777 list at [72]gcc (a] gcc.gnu.org. All of [73]our lists have public 1778 archives. 1779 1780 Copyright (C) [74]Free Software Foundation, Inc. Verbatim copying and 1781 distribution of this entire article is permitted in any medium, 1782 provided this notice is preserved. 1783 1784 These pages are [75]maintained by the GCC team. Last modified 1785 2022-05-27[76]. 1786 1787 References 1788 1789 1. http://gcc.gnu.org/gcc-9/porting_to.html 1790 2. http://gcc.gnu.org/onlinedocs/index.html#current 1791 3. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88469 1792 4. https://gcc.gnu.org/ml/gcc/2018-10/msg00139.html 1793 5. https://gcc.gnu.org/ml/gcc/2019-04/msg00023.html 1794 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90920 1795 7. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-frepo 1796 8. https://gcc.gnu.org/PR90361 1797 9. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-GCC.html#Invoking-GCC 1798 10. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-flive-patching 1799 11. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-line-numbers 1800 12. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-labels 1801 13. 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https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fversion-loops-for-strides 1819 31. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-interchange 1820 32. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-unroll-and-jam 1821 33. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-ftree-loop-distribution 1822 34. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-Gcov.html#Invoking-Gcov 1823 35. https://www.openacc.org/ 1824 36. https://gcc.gnu.org/wiki/OpenACC/Implementation Status#status-9 1825 37. https://www.openmp.org/specifications/ 1826 38. https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00628.html 1827 39. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Vector-Extensions.html#index-_005f_005fbuiltin_005fconvertvector 1828 40. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Waddress-of-packed-member 1829 41. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Warray-bounds 1830 42. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wattribute-alias 1831 43. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wformat-overflow 1832 44. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wformat-truncation 1833 45. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wmissing-attributes 1834 46. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wstringop-truncation 1835 47. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Wabsolute-value 1836 48. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wdeprecated-copy 1837 49. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Winit-list-lifetime 1838 50. 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1858 70. https://gcc.gnu.org/onlinedocs/ 1859 71. mailto:gcc-help (a] gcc.gnu.org 1860 72. mailto:gcc (a] gcc.gnu.org 1861 73. https://gcc.gnu.org/lists.html 1862 74. https://www.fsf.org/ 1863 75. https://gcc.gnu.org/about.html 1864 76. http://validator.w3.org/check/referer 1865 ====================================================================== 1866 http://gcc.gnu.org/gcc-8/index.html 1867 GCC 8 Release Series 1868 1869 (This release series is no longer supported.) 1870 1871 May 14, 2021 1872 1873 The [1]GNU project and the GCC developers are pleased to announce the 1874 release of GCC 8.5. 1875 1876 This release is a bug-fix release, containing fixes for regressions in 1877 GCC 8.4 relative to previous releases of GCC. 1878 1879 Release History 1880 1881 GCC 8.5 1882 May 14, 2021 ([2]changes, [3]documentation) 1883 1884 GCC 8.4 1885 Mar 4, 2020 ([4]changes, [5]documentation) 1886 1887 GCC 8.3 1888 Feb 22, 2019 ([6]changes, [7]documentation) 1889 1890 GCC 8.2 1891 Jul 26, 2018 ([8]changes, [9]documentation) 1892 1893 GCC 8.1 1894 May 2, 2018 ([10]changes, [11]documentation) 1895 1896 References and Acknowledgements 1897 1898 GCC used to stand for the GNU C Compiler, but since the compiler 1899 supports several other languages aside from C, it now stands for the 1900 GNU Compiler Collection. 1901 1902 A list of [12]successful builds is updated as new information becomes 1903 available. 1904 1905 The GCC developers would like to thank the numerous people that have 1906 contributed new features, improvements, bug fixes, and other changes as 1907 well as test results to GCC. This [13]amazing group of volunteers is 1908 what makes GCC successful. 1909 1910 For additional information about GCC please refer to the [14]GCC 1911 project web site or contact the [15]GCC development mailing list. 1912 1913 To obtain GCC please use [16]our mirror sites or [17]our version 1914 control system. 1915 1916 1917 For questions related to the use of GCC, please consult these web 1918 pages and the [18]GCC manuals. If that fails, the 1919 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1920 web pages and the development of GCC are welcome on our developer 1921 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 1922 archives. 1923 1924 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 1925 distribution of this entire article is permitted in any medium, 1926 provided this notice is preserved. 1927 1928 These pages are [23]maintained by the GCC team. Last modified 1929 2022-05-06[24]. 1930 1931 References 1932 1933 1. http://www.gnu.org/ 1934 2. http://gcc.gnu.org/gcc-8/changes.html 1935 3. http://gcc.gnu.org/onlinedocs/8.5.0/ 1936 4. http://gcc.gnu.org/gcc-8/changes.html 1937 5. http://gcc.gnu.org/onlinedocs/8.4.0/ 1938 6. http://gcc.gnu.org/gcc-8/changes.html 1939 7. http://gcc.gnu.org/onlinedocs/8.3.0/ 1940 8. http://gcc.gnu.org/gcc-8/changes.html 1941 9. http://gcc.gnu.org/onlinedocs/8.2.0/ 1942 10. http://gcc.gnu.org/gcc-8/changes.html 1943 11. http://gcc.gnu.org/onlinedocs/8.1.0/ 1944 12. http://gcc.gnu.org/gcc-8/buildstat.html 1945 13. http://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Contributors.html 1946 14. http://gcc.gnu.org/index.html 1947 15. mailto:gcc (a] gcc.gnu.org 1948 16. http://gcc.gnu.org/mirrors.html 1949 17. http://gcc.gnu.org/git.html 1950 18. https://gcc.gnu.org/onlinedocs/ 1951 19. mailto:gcc-help (a] gcc.gnu.org 1952 20. mailto:gcc (a] gcc.gnu.org 1953 21. https://gcc.gnu.org/lists.html 1954 22. https://www.fsf.org/ 1955 23. https://gcc.gnu.org/about.html 1956 24. http://validator.w3.org/check/referer 1957 ====================================================================== 1958 http://gcc.gnu.org/gcc-8/changes.html 1959 GCC 8 Release Series 1960 Changes, New Features, and Fixes 1961 1962 This page is a "brief" summary of some of the huge number of 1963 improvements in GCC 8. You may also want to check out our [1]Porting to 1964 GCC 8 page and the [2]full GCC documentation. 1965 1966 Caveats 1967 1968 * Support for the obsolete SDB/coff debug info format has been 1969 removed. The option -gcoff no longer does anything. 1970 * The Cilk+ extensions to the C and C++ languages have been removed. 1971 * The MPX extensions to the C and C++ languages have been deprecated 1972 and will be removed in a future release. 1973 * The extension allowing arithmetic on std::atomic<void*> and types 1974 like std::atomic<R(*)()> has been deprecated. 1975 * The non-standard C++0x std::copy_exception function was removed. 1976 std::make_exception_ptr should be used instead. 1977 * Support for the powerpc*-*-*spe* target ports which have been 1978 recently unmaintained and untested in GCC has been declared 1979 obsolete in GCC 8 as [3]announced. Unless there is activity to 1980 revive them, the next release of GCC will have their sources 1981 permanently removed. 1982 1983 General Improvements 1984 1985 * Inter-procedural optimization improvements: 1986 + Reworked run-time estimation metrics leading to more realistic 1987 guesses driving inliner and cloning heuristics. 1988 + The ipa-pure-const pass is extended to propagate the malloc 1989 attribute, and the corresponding warning option 1990 -Wsuggest-attribute=malloc emits a diagnostic for functions 1991 which can be annotated with the malloc attribute. 1992 * Profile driven optimization improvements: 1993 + New infrastructure for representing profiles (both statically 1994 guessed and profile feedback) which allows propagation of 1995 additional information about the reliability of the profile. 1996 + A number of improvements in the profile updating code solving 1997 problems found by new verification code. 1998 + Static detection of code which is not executed in a valid run 1999 of the program. This includes paths which trigger undefined 2000 behavior as well as calls to functions declared with the cold 2001 attribute. Newly the noreturn attribute does not imply all 2002 effects of cold to differentiate between exit (which is 2003 noreturn) and abort (which is in addition not executed in 2004 valid runs). 2005 + -freorder-blocks-and-partition, a pass splitting function 2006 bodies into hot and cold regions, is now enabled by default at 2007 -O2 and higher for x86 and x86-64. 2008 * Link-time optimization improvements: 2009 + We have significantly improved debug information on ELF 2010 targets using DWARF by properly preserving language-specific 2011 information. This allows for example the libstdc++ 2012 pretty-printers to work with LTO optimized executables. 2013 * A new option -fcf-protection=[full|branch|return|none] is 2014 introduced to perform code instrumentation to increase program 2015 security by checking that target addresses of control-flow transfer 2016 instructions (such as indirect function call, function return, 2017 indirect jump) are valid. Currently the instrumentation is 2018 supported on x86 GNU/Linux targets only. See the user guide for 2019 further information about the option syntax and section "New 2020 Targets and Target Specific Improvements" for IA-32/x86-64 for more 2021 details. 2022 * The -gcolumn-info option is now enabled by default. It includes 2023 column information in addition to just filenames and line numbers 2024 in DWARF debugging information. 2025 * The polyhedral-based loop nest optimization pass 2026 -floop-nest-optimize has been overhauled. It's still considered 2027 experimental and may not result in any runtime improvements. 2028 * Two new classical loop nest optimization passes have been added. 2029 -floop-unroll-and-jam performs outer loop unrolling and fusing of 2030 the inner loop copies. -floop-interchange exchanges loops in a loop 2031 nest to improve data locality. Both passes are enabled by default 2032 at -O3 and above. 2033 * The classic loop nest optimization pass -ftree-loop-distribution 2034 has been improved and enabled by default at -O3 and above. It 2035 supports loop nest distribution in some restricted scenarios; it 2036 also supports cancellable innermost loop distribution with loop 2037 versioning under run-time alias checks. 2038 * The new option -fstack-clash-protection causes the compiler to 2039 insert probes whenever stack space is allocated statically or 2040 dynamically to reliably detect stack overflows and thus mitigate 2041 the attack vector that relies on jumping over a stack guard page as 2042 provided by the operating system. 2043 * A new pragma GCC unroll has been implemented in the C family of 2044 languages, as well as Fortran and Ada, so as to make it possible 2045 for the user to have a finer-grained control over the loop 2046 unrolling optimization. 2047 * GCC has been enhanced to detect more instances of meaningless or 2048 mutually exclusive attribute specifications and handle such 2049 conflicts more consistently. Mutually exclusive attribute 2050 specifications are ignored with a warning regardless of whether 2051 they appear on the same declaration or on distinct declarations of 2052 the same entity. For example, because the noreturn attribute on the 2053 second declaration below is mutually exclusive with the malloc 2054 attribute on the first, it is ignored and a warning is issued. 2055 > 2056 void* __attribute__ ((malloc)) f (unsigned); 2057 void* __attribute__ ((noreturn)) f (unsigned); 2058 2059 warning: ignoring attribute 'noreturn' because it conflicts with attribute 2060 'malloc' [-Wattributes] 2061 * The gcov tool can distinguish functions that begin on a same line 2062 in a source file. This can be a different template instantiation or 2063 a class constructor: 2064 2065 File 'ins.C' 2066 Lines executed:100.00% of 8 2067 Creating 'ins.C.gcov' 2068 2069 -: 0:Source:ins.C 2070 -: 0:Graph:ins.gcno 2071 -: 0:Data:ins.gcda 2072 -: 0:Runs:1 2073 -: 0:Programs:1 2074 -: 1:template<class T> 2075 -: 2:class Foo 2076 -: 3:{ 2077 -: 4: public: 2078 2: 5: Foo(): b (1000) {} 2079 ------------------ 2080 Foo<char>::Foo(): 2081 1: 5: Foo(): b (1000) {} 2082 ------------------ 2083 Foo<int>::Foo(): 2084 1: 5: Foo(): b (1000) {} 2085 ------------------ 2086 2: 6: void inc () { b++; } 2087 ------------------ 2088 Foo<char>::inc(): 2089 1: 6: void inc () { b++; } 2090 ------------------ 2091 Foo<int>::inc(): 2092 1: 6: void inc () { b++; } 2093 ------------------ 2094 -: 7: 2095 -: 8: private: 2096 -: 9: int b; 2097 -: 10:}; 2098 -: 11: 2099 1: 12:int main(int argc, char **argv) 2100 -: 13:{ 2101 1: 14: Foo<int> a; 2102 1: 15: Foo<char> b; 2103 -: 16: 2104 1: 17: a.inc (); 2105 1: 18: b.inc (); 2106 1: 19:} 2107 2108 * The gcov tool has more accurate numbers for execution of lines in a 2109 source file. 2110 * The gcov tool can use TERM colors to provide more readable output. 2111 * AddressSanitizer gained a new pair of sanitization options, 2112 -fsanitize=pointer-compare and -fsanitize=pointer-subtract, which 2113 warn about subtraction (or comparison) of pointers that point to a 2114 different memory object: 2115 2116 int 2117 main () 2118 { 2119 /* Heap allocated memory. */ 2120 char *heap1 = (char *)__builtin_malloc (42); 2121 char *heap2 = (char *)__builtin_malloc (42); 2122 if (heap1 > heap2) 2123 return 1; 2124 2125 return 0; 2126 } 2127 2128 ==17465==ERROR: AddressSanitizer: invalid-pointer-pair: 0x604000000010 0x6040000 2129 00050 2130 #0 0x40070f in main /tmp/pointer-compare.c:7 2131 #1 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2132 #2 0x400629 in _start (/tmp/a.out+0x400629) 2133 2134 0x604000000010 is located 0 bytes inside of 42-byte region [0x604000000010,0x604 2135 00000003a) 2136 allocated by thread T0 here: 2137 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 2138 _malloc_linux.cc:86 2139 #1 0x4006ea in main /tmp/pointer-compare.c:5 2140 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2141 2142 0x604000000050 is located 0 bytes inside of 42-byte region [0x604000000050,0x604 2143 00000007a) 2144 allocated by thread T0 here: 2145 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 2146 _malloc_linux.cc:86 2147 #1 0x4006f8 in main /tmp/pointer-compare.c:6 2148 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2149 2150 SUMMARY: AddressSanitizer: invalid-pointer-pair /tmp/pointer-compare.c:7 in main 2151 2152 * The store merging pass has been enhanced to handle bit-fields and 2153 not just constant stores, but also data copying from adjacent 2154 memory locations into other adjacent memory locations, including 2155 bitwise logical operations on the data. The pass can also handle 2156 byte swapping into memory locations. 2157 * The undefined behavior sanitizer gained two new options included in 2158 -fsanitize=undefined: -fsanitize=builtin which diagnoses at run 2159 time invalid arguments to __builtin_clz or __builtin_ctz prefixed 2160 builtins, and -fsanitize=pointer-overflow which performs cheap run 2161 time tests for pointer wrapping. 2162 * A new attribute no_sanitize can be applied to functions to instruct 2163 the compiler not to do sanitization of the options provided as 2164 arguments to the attribute. Acceptable values for no_sanitize match 2165 those acceptable by the -fsanitize command-line option. 2166 2167 void __attribute__ ((no_sanitize ("alignment", "object-size"))) 2168 f () { /* Do something. */; } 2169 2170 New Languages and Language specific improvements 2171 2172 Ada 2173 2174 * For its internal exception handling used on the host for error 2175 recovery in the front-end, the compiler now relies on the native 2176 exception handling mechanism of the host platform, which should be 2177 more efficient than the former mechanism. 2178 2179 BRIG (HSAIL) 2180 2181 In this release cycle, the focus for the BRIGFE was on stabilization 2182 and performance improvements. Also a couple of completely new features 2183 were added. 2184 * Improved support for function and module scope group segment 2185 variables. PRM specs define function and module scope group segment 2186 variables as an experimental feature. However, PRM test suite uses 2187 them. Now group segment is handled by separate book keeping of 2188 module scope and function (kernel) offsets. Each function has a 2189 "frame" in the group segment offset to which is given as an 2190 argument, similar to traditional call stack frame handling. 2191 * Reduce the number of type conversions due to the untyped HSAIL 2192 registers. Instead of always representing the HSAIL's untyped 2193 registers as unsigned int, the gccbrig now pre-analyzes the BRIG 2194 code and builds the register variables as a type used the most when 2195 storing or reading data to/from each register. This reduces the 2196 number of total casts which cannot be always optimized away. 2197 * Support for BRIG_KIND_NONE directives. 2198 * Made -O3 the default optimization level for BRIGFE. 2199 * Fixed illegal addresses generated from address expressions which 2200 refer only to offset 0. 2201 * Fixed a bug with reg+offset addressing on 32b segments. In 'large' 2202 mode, the offset is treated as 32-bit unless it's in global, 2203 read-only or kernarg address space. 2204 * Fixed a crash caused sometimes by calls with more than 4 arguments. 2205 * Fixed a mis-execution issue with kernels that have both unexpanded 2206 ID functions and calls to subfunctions. 2207 * Treat HSAIL barrier builtins as setjmp/longjump style functions to 2208 avoid illegal optimizations. 2209 * Ensure per WI copies of private variables are aligned correctly. 2210 * libhsail-rt: Assume the host runtime allocates the work group 2211 memory. 2212 2213 C family 2214 2215 * New command-line options have been added for the C and C++ 2216 compilers: 2217 + [4]-Wmultistatement-macros warns about unsafe macros expanding 2218 to multiple statements used as a body of a statement such as 2219 if, else, while, switch, or for. 2220 + [5]-Wstringop-truncation warns for calls to bounded string 2221 manipulation functions such as strncat, strncpy, and stpncpy 2222 that might either truncate the copied string or leave the 2223 destination unchanged. For example, the following call to 2224 strncat is diagnosed because it appends just three of the four 2225 characters from the source string. 2226 void append (char *buf, size_t bufsize) 2227 { 2228 strncat (buf, ".txt", 3); 2229 } 2230 warning: 'strncat' output truncated copying 3 bytes from a string of length 4 [- 2231 Wstringop-truncation] 2232 Similarly, in the following example, the call to strncpy 2233 specifies the size of the destination buffer as the bound. If 2234 the length of the source string is equal to or greater than 2235 this size the result of the copy will not be NUL-terminated. 2236 Therefore, the call is also diagnosed. To avoid the warning, 2237 specify sizeof buf - 1 as the bound and set the last element 2238 of the buffer to NUL. 2239 void copy (const char *s) 2240 { 2241 char buf[80]; 2242 strncpy (buf, s, sizeof buf); 2243 2244 } 2245 warning: 'strncpy' specified bound 80 equals destination size [-Wstringop-trunca 2246 tion] 2247 The -Wstringop-truncation option is included in -Wall. 2248 Note that due to GCC bug [6]82944, defining strncat, strncpy, 2249 or stpncpy as a macro in a system header as some 2250 implementations do, suppresses the warning. 2251 + [7]-Wif-not-aligned controls warnings issued in response to 2252 invalid uses of objects declared with attribute 2253 [8]warn_if_not_aligned. 2254 The -Wif-not-aligned option is included in -Wall. 2255 + [9]-Wmissing-attributes warns when a declaration of a function 2256 is missing one or more attributes that a related function is 2257 declared with and whose absence may adversely affect the 2258 correctness or efficiency of generated code. For example, in 2259 C++, the warning is issued when an explicit specialization of 2260 a primary template declared with attribute alloc_align, 2261 alloc_size, assume_aligned, format, format_arg, malloc, or 2262 nonnull is declared without it. Attributes deprecated, error, 2263 and warning suppress the warning. 2264 The -Wmissing-attributes option is included in -Wall. 2265 + [10]-Wpacked-not-aligned warns when a struct or union declared 2266 with attribute packed defines a member with an explicitly 2267 specified alignment greater than 1. Such a member will wind up 2268 under-aligned. For example, a warning will be issued for the 2269 definition of struct A in the following: 2270 struct __attribute__ ((aligned (8))) 2271 S8 { char a[8]; }; 2272 2273 struct __attribute__ ((packed)) A 2274 { 2275 struct S8 s8; 2276 }; 2277 warning: alignment 1 of 'struct S' is less than 8 [-Wpacked-not-aligned] 2278 The -Wpacked-not-aligned option is included in -Wall. 2279 + -Wcast-function-type warns when a function pointer is cast to 2280 an incompatible function pointer. This warning is enabled by 2281 -Wextra. 2282 + -Wsizeof-pointer-div warns for suspicious divisions of the 2283 size of a pointer by the size of the elements it points to, 2284 which looks like the usual way to compute the array size but 2285 won't work out correctly with pointers. This warning is 2286 enabled by -Wall. 2287 + -Wcast-align=strict warns whenever a pointer is cast such that 2288 the required alignment of the target is increased. For 2289 example, warn if a char * is cast to an int * regardless of 2290 the target machine. 2291 + -fprofile-abs-path creates absolute path names in the .gcno 2292 files. This allows gcov to find the correct sources in 2293 projects where compilations occur with different working 2294 directories. 2295 * -fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer and 2296 signed integer overflow is now undefined by default at all 2297 optimization levels. Using -fsanitize=signed-integer-overflow is 2298 now the preferred way to audit code, -Wstrict-overflow is 2299 deprecated. 2300 * The [11]-Warray-bounds option has been improved to detect more 2301 instances of out-of-bounds array indices and pointer offsets. For 2302 example, negative or excessive indices into flexible array members 2303 and string literals are detected. 2304 * The [12]-Wrestrict option introduced in GCC 7 has been enhanced to 2305 detect many more instances of overlapping accesses to objects via 2306 restrict-qualified arguments to standard memory and string 2307 manipulation functions such as memcpy and strcpy. For example, the 2308 strcpy call in the function below attempts to truncate the string 2309 by replacing its initial characters with the last four. However, 2310 because the function writes the terminating NUL into a[4], the 2311 copies overlap and the call is diagnosed. 2312 void f (void) 2313 { 2314 char a[] = "abcd1234"; 2315 strcpy (a, a + 4); 2316 2317 } 2318 warning: 'strcpy' accessing 5 bytes at offsets 0 and 4 overlaps 1 byte at offset 2319 4 [-Wrestrict] 2320 The -Wrestrict option is included in -Wall. 2321 * Several optimizer enhancements have enabled improvements to the 2322 [13]-Wformat-overflow and [14]-Wformat-truncation options. The 2323 warnings detect more instances of buffer overflow and truncation 2324 than in GCC 7 and are better at avoiding certain kinds of false 2325 positives. 2326 * When reporting mismatching argument types at a function call, the C 2327 and C++ compilers now underline both the argument and the pertinent 2328 parameter in the declaration. 2329 $ gcc arg-type-mismatch.cc 2330 arg-type-mismatch.cc: In function 'int caller(int, int, float)': 2331 arg-type-mismatch.cc:5:24: error: invalid conversion from 'int' to 'const char*' 2332 [-fpermissive] 2333 return callee(first, second, third); 2334 ^~~~~~ 2335 arg-type-mismatch.cc:1:40: note: initializing argument 2 of 'int callee(int, c 2336 onst char*, float)' 2337 extern int callee(int one, const char *two, float three); 2338 ~~~~~~~~~~~~^~~ 2339 2340 * When reporting on unrecognized identifiers, the C and C++ compilers 2341 will now emit fix-it hints suggesting #include directives for 2342 various headers in the C and C++ standard libraries. 2343 $ gcc incomplete.c 2344 incomplete.c: In function 'test': 2345 incomplete.c:3:10: error: 'NULL' undeclared (first use in this function) 2346 return NULL; 2347 ^~~~ 2348 incomplete.c:3:10: note: 'NULL' is defined in header '<stddef.h>'; did you forge 2349 t to '#include <stddef.h>'? 2350 incomplete.c:1:1: 2351 +#include <stddef.h> 2352 const char *test(void) 2353 incomplete.c:3:10: 2354 return NULL; 2355 ^~~~ 2356 incomplete.c:3:10: note: each undeclared identifier is reported only once for ea 2357 ch function it appears in 2358 2359 $ gcc incomplete.cc 2360 incomplete.cc:1:6: error: 'string' in namespace 'std' does not name a type 2361 std::string s("hello world"); 2362 ^~~~~~ 2363 incomplete.cc:1:1: note: 'std::string' is defined in header '<string>'; did you 2364 forget to '#include <string>'? 2365 +#include <string> 2366 std::string s("hello world"); 2367 ^~~ 2368 2369 * The C and C++ compilers now use more intuitive locations when 2370 reporting on missing semicolons, and offer fix-it hints: 2371 $ gcc t.c 2372 t.c: In function 'test': 2373 t.c:3:12: error: expected ';' before '}' token 2374 return 42 2375 ^ 2376 ; 2377 } 2378 ~ 2379 2380 * When reporting on missing '}' and ')' tokens, the C and C++ 2381 compilers will now highlight the corresponding '{' and '(' token, 2382 issuing a 'note' if it's on a separate line: 2383 $ gcc unclosed.c 2384 unclosed.c: In function 'log_when_out_of_range': 2385 unclosed.c:12:50: error: expected ')' before '{' token 2386 && (temperature < MIN || temperature > MAX) { 2387 ^~ 2388 ) 2389 unclosed.c:11:6: note: to match this '(' 2390 if (logging_enabled && check_range () 2391 ^ 2392 2393 or highlighting it directly if it's on the same line: 2394 $ gcc unclosed-2.c 2395 unclosed-2.c: In function 'test': 2396 unclosed-2.c:8:45: error: expected ')' before '{' token 2397 if (temperature < MIN || temperature > MAX { 2398 ~ ^~ 2399 ) 2400 2401 They will also emit fix-it hints. 2402 2403 C++ 2404 2405 * GCC 8 (-fabi-version=12) has a couple of corrections to the calling 2406 convention, which changes the ABI for some uncommon code: 2407 + Passing an empty class as an argument now takes up no space on 2408 x86_64, as required by the psABI. 2409 + Passing or returning a class with only deleted copy and move 2410 constructors now uses the same calling convention as a class 2411 with a non-trivial copy or move constructor. This only affects 2412 C++17 mode, as in earlier standards passing or returning such 2413 a class was impossible. 2414 + WARNING: In GCC 8.1 the second change mistakenly also affects 2415 classes with a deleted copy constructor and defaulted trivial 2416 move constructor (bug [15]c++/86094). This issue is fixed in 2417 GCC 8.2 (-fabi-version=13). 2418 You can test whether these changes affect your code with -Wabi=11 2419 (or -Wabi=12 in GCC 8.2 for the third issue); if these changes are 2420 problematic for your project, the GCC 7 ABI can be selected with 2421 -fabi-version=11. 2422 * The value of the C++11 alignof operator has been corrected to match 2423 C _Alignof (minimum alignment) rather than GNU __alignof__ 2424 (preferred alignment); on ia32 targets this means that 2425 alignof(double) is now 4 rather than 8. Code that wants the 2426 preferred alignment should use __alignof__ instead. 2427 * New command-line options have been added for the C++ compiler to 2428 control warnings: 2429 + [16]-Wclass-memaccess warns when objects of non-trivial class 2430 types are manipulated in potentially unsafe ways by raw memory 2431 functions such as memcpy, or realloc. The warning helps detect 2432 calls that bypass user-defined constructors or copy-assignment 2433 operators, corrupt virtual table pointers, data members of 2434 const-qualified types or references, or member pointers. The 2435 warning also detects calls that would bypass access controls 2436 to data members. For example, a call such as: 2437 memcpy (&std::cout, &std::cerr, sizeof std::cout); 2438 results in 2439 warning: 'void* memcpy(void*, const void*, long unsigned int)' writing t 2440 o an object of type 'std::ostream' {aka 'class std::basic_ostream<char>'} with n 2441 o trivial copy-assignment [-Wclass-memaccess] 2442 The -Wclass-memaccess option is included in -Wall. 2443 * The C++ front end has experimental support for some of the upcoming 2444 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 2445 including designated initializers, default member initializers for 2446 bit-fields, __VA_OPT__ (except that #__VA_OPT__ is unsupported), 2447 lambda [=, this] captures, etc. For a full list of new features, 2448 see [17]the C++ status page. 2449 * When reporting on attempts to access private fields of a class or 2450 struct, the C++ compiler will now offer fix-it hints showing how to 2451 use an accessor function to get at the field in question, if one 2452 exists. 2453 $ gcc accessor.cc 2454 accessor.cc: In function 'void test(foo*)': 2455 accessor.cc:12:12: error: 'double foo::m_ratio' is private within this context 2456 if (ptr->m_ratio >= 0.5) 2457 ^~~~~~~ 2458 accessor.cc:7:10: note: declared private here 2459 double m_ratio; 2460 ^~~~~~~ 2461 accessor.cc:12:12: note: field 'double foo::m_ratio' can be accessed via 'double 2462 foo::get_ratio() const' 2463 if (ptr->m_ratio >= 0.5) 2464 ^~~~~~~ 2465 get_ratio() 2466 2467 * The C++ compiler can now give you a hint if you use a macro before 2468 it was defined (e.g. if you mess up the order of your #include 2469 directives): 2470 $ gcc ordering.cc 2471 ordering.cc:2:24: error: expected ';' at end of member declaration 2472 virtual void clone() const OVERRIDE { } 2473 ^~~~~ 2474 ; 2475 ordering.cc:2:30: error: 'OVERRIDE' does not name a type 2476 virtual void clone() const OVERRIDE { } 2477 ^~~~~~~~ 2478 ordering.cc:2:30: note: the macro 'OVERRIDE' had not yet been defined 2479 In file included from ordering.cc:5: 2480 c++11-compat.h:2: note: it was later defined here 2481 #define OVERRIDE override 2482 2483 2484 * The -Wold-style-cast diagnostic can now emit fix-it hints telling 2485 you when you can use a static_cast, const_cast, or 2486 reinterpret_cast. 2487 $ gcc -c old-style-cast-fixits.cc -Wold-style-cast 2488 old-style-cast-fixits.cc: In function 'void test(void*)': 2489 old-style-cast-fixits.cc:5:19: warning: use of old-style cast to 'struct foo*' [ 2490 -Wold-style-cast] 2491 foo *f = (foo *)ptr; 2492 ^~~ 2493 ---------- 2494 static_cast<foo *> (ptr) 2495 2496 * When reporting on problems within extern "C" linkage 2497 specifications, the C++ compiler will now display the location of 2498 the start of the extern "C". 2499 $ gcc -c extern-c.cc 2500 extern-c.cc:3:1: error: template with C linkage 2501 template <typename T> void test (void); 2502 ^~~~~~~~ 2503 In file included from extern-c.cc:1: 2504 unclosed.h:1:1: note: 'extern "C"' linkage started here 2505 extern "C" { 2506 ^~~~~~~~~~ 2507 extern-c.cc:3:39: error: expected '}' at end of input 2508 template <typename T> void test (void); 2509 ^ 2510 In file included from extern-c.cc:1: 2511 unclosed.h:1:12: note: to match this '{' 2512 extern "C" { 2513 ^ 2514 2515 * When reporting on mismatching template types, the C++ compiler will 2516 now use color to highlight the mismatching parts of the template, 2517 and will elide the parameters that are common between two 2518 mismatching templates, printing [...] instead: 2519 $ gcc templates.cc 2520 templates.cc: In function 'void test()': 2521 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 2522 e>' to 'vector<int>' 2523 fn_1(vector<double> ()); 2524 ^~~~~~~~~~~~~~~~~ 2525 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<[...] 2526 ,double>' to 'map<[...],int>' 2527 fn_2(map<int, double>()); 2528 ^~~~~~~~~~~~~~~~~~ 2529 2530 Those [...] elided parameters can be seen using -fno-elide-type: 2531 $ gcc templates.cc -fno-elide-type 2532 templates.cc: In function 'void test()': 2533 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 2534 e>' to 'vector<int>' 2535 fn_1(vector<double> ()); 2536 ^~~~~~~~~~~~~~~~~ 2537 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<int,d 2538 ouble>' to 'map<int,int>' 2539 fn_2(map<int, double>()); 2540 ^~~~~~~~~~~~~~~~~~ 2541 2542 The C++ compiler has also gained an option 2543 -fdiagnostics-show-template-tree which visualizes such mismatching 2544 templates in a hierarchical form: 2545 $ gcc templates-2.cc -fdiagnostics-show-template-tree 2546 templates-2.cc: In function 'void test()': 2547 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 2548 ble>' to 'vector<int>' 2549 vector< 2550 [double != int]> 2551 fn_1(vector<double> ()); 2552 ^~~~~~~~~~~~~~~~~ 2553 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 2554 ctor<double> >()' from 'map<map<[...],vector<double>>,vector<double>>' to 'map<m 2555 ap<[...],vector<float>>,vector<float>>' 2556 map< 2557 map< 2558 [...], 2559 vector< 2560 [double != float]>>, 2561 vector< 2562 [double != float]>> 2563 fn_2(map<map<int, vector<double>>, vector<double>> ()); 2564 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2565 2566 which again works with -fno-elide-type: 2567 $ gcc templates-2.cc -fdiagnostics-show-template-tree -fno-elide-type 2568 templates-2.cc: In function 'void test()': 2569 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 2570 ble>' to 'vector<int>' 2571 vector< 2572 [double != int]> 2573 fn_1(vector<double> ()); 2574 ^~~~~~~~~~~~~~~~~ 2575 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 2576 ctor<double> >()' from 'map<map<int,vector<double>>,vector<double>>' to 'map<map 2577 <int,vector<float>>,vector<float>>' 2578 map< 2579 map< 2580 int, 2581 vector< 2582 [double != float]>>, 2583 vector< 2584 [double != float]>> 2585 fn_2(map<map<int, vector<double>>, vector<double>> ()); 2586 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2587 2588 * Flowing off the end of a non-void function is considered 2589 unreachable and may be subject to optimization on that basis. As a 2590 result of this change, -Wreturn-type warnings are enabled by 2591 default for C++. 2592 2593 Runtime Library (libstdc++) 2594 2595 * Improved experimental support for C++17, including the following 2596 features: 2597 + Deduction guides to support class template argument deduction. 2598 + std::filesystem implementation. 2599 + std::char_traits<char> and std::char_traits<wchar_t> are 2600 usable in constant expressions. 2601 + std::to_chars and std::from_chars (for integers only, not for 2602 floating point types). 2603 * Experimental support for C++2a: std::to_address (thanks to Glen 2604 Fernandes) and std::endian. 2605 * On GNU/Linux, std::random_device::entropy() accesses the kernel's 2606 entropy count for the random device, if known (thanks to Xi 2607 Ruoyao). 2608 * Support for std::experimental::source_location. 2609 * AddressSanitizer integration for std::vector, detecting 2610 out-of-range accesses to the unused capacity of a vector. 2611 * Extensions __gnu_cxx::airy_ai and __gnu_cxx::airy_bi added to the 2612 Mathematical Special Functions. 2613 2614 Fortran 2615 2616 * The main version of libfortran has been changed to 5. 2617 * Parameterized derived types, a major feature of Fortran 2003, have 2618 been implemented. 2619 * Partial support is provided for Fortran 2018 teams, which are 2620 hierarchical subsets of images that execute independently of other 2621 image subsets. 2622 * The maximum rank for arrays has been increased to 15, conforming to 2623 the Fortran 2008 standard. 2624 * Transformational intrinsics are now fully supported in 2625 initialization expressions. 2626 * New flag -fc-prototypes to write C prototypes for BIND(C) 2627 procedures and variables. 2628 * If -fmax-stack-var-size is honored if given together with -Ofast, 2629 -fstack-arrays is no longer set in that case. 2630 * New options -fdefault-real-16 and -fdefault-real-10 to control the 2631 default kind of REAL variables. 2632 * A warning is now issued if an array subscript inside a DO loop 2633 could lead to an out-of-bounds-access. The new option 2634 -Wdo-subscript, enabled by -Wextra, warns about this even if the 2635 compiler can not prove that the code will be executed. 2636 * The Fortran front end now attempts to interchange loops if it is 2637 deemed profitable. So far, this is restricted to FORALL and DO 2638 CONCURRENT statements with multiple indices. This behavior be 2639 controlled with the new flag -ffrontend-loop-interchange, which is 2640 enabled with optimization by default. The 2641 -Wfrontend-loop-interchange option warns about such occurrences. 2642 * When an actual argument contains too few elements for a dummy 2643 argument, an error is now issued. The -std=legacy option can be 2644 used to still compile such code. 2645 * The RECL= argument to OPEN and INQUIRE statements now allows 64-bit 2646 integers, making records larger than 2GiB possible. 2647 * The GFORTRAN_DEFAULT_RECL environment variable no longer has any 2648 effect. The record length for preconnected units is now larger than 2649 any practical limit, same as for sequential access units opened 2650 without an explicit RECL= specifier. 2651 * Character variables longer than HUGE(0) elements are now possible 2652 on 64-bit targets. Note that this changes the procedure call ABI 2653 for all procedures with character arguments on 64-bit targets, as 2654 the type of the hidden character length argument has changed. The 2655 hidden character length argument is now of type INTEGER(C_SIZE_T). 2656 * Partial support is provided for Fortran 2018 teams, which are 2657 hierarchical subsets of images that execute independently of other 2658 image subsets. 2659 2660 Go 2661 2662 * GCC 8 provides a complete implementation of the Go 1.10.1 user 2663 packages. 2664 * The garbage collector is now fully concurrent. As before, values 2665 stored on the stack are scanned conservatively, but value stored in 2666 the heap are scanned precisely. 2667 * Escape analysis is fully implemented and enabled by default in the 2668 Go front end. This significantly reduces the number of heap 2669 allocations by allocating values on the stack instead. 2670 2671 libgccjit 2672 2673 The libgccjit API gained four new entry points: 2674 * [18]gcc_jit_type_get_vector and 2675 * [19]gcc_jit_context_new_rvalue_from_vector for working with 2676 vectors, 2677 * [20]gcc_jit_type_get_aligned 2678 * [21]gcc_jit_function_get_address 2679 2680 The C code generated by [22]gcc_jit_context_dump_reproducer_to_file is 2681 now easier-to-read. 2682 2683 New Targets and Target Specific Improvements 2684 2685 AArch64 2686 2687 * The Armv8.4-A architecture is now supported. It can be used by 2688 specifying the -march=armv8.4-a option. 2689 * The Dot Product instructions are now supported as an optional 2690 extension to the Armv8.2-A architecture and newer and are mandatory 2691 on Armv8.4-A. The extension can be used by specifying the +dotprod 2692 architecture extension. E.g. -march=armv8.2-a+dotprod. 2693 * The Armv8-A +crypto extension has now been split into two 2694 extensions for finer grained control: 2695 + +aes which contains the Armv8-A AES crytographic instructions. 2696 + +sha2 which contains the Armv8-A SHA2 and SHA1 cryptographic 2697 instructions. 2698 Using +crypto will now enable these two extensions. 2699 * New Armv8.4-A FP16 Floating Point Multiplication Variant 2700 instructions have been added. These instructions are mandatory in 2701 Armv8.4-A but available as an optional extension to Armv8.2-A and 2702 Armv8.3-A. The new extension can be used by specifying the +fp16fml 2703 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 2704 the instructions can be enabled by specifying +fp16. 2705 * New cryptographic instructions have been added as optional 2706 extensions to Armv8.2-A and newer. These instructions can be 2707 enabled with: 2708 + +sha3 New SHA3 and SHA2 instructions from Armv8.4-A. This 2709 implies +sha2. 2710 + +sm4 New SM3 and SM4 instructions from Armv8.4-A. 2711 * The Scalable Vector Extension (SVE) is now supported as an optional 2712 extension to the Armv8.2-A architecture and newer. This support 2713 includes automatic vectorization with SVE instructions, but it does 2714 not yet include the SVE Arm C Language Extensions (ACLE). It can be 2715 enabled by specifying the +sve architecture extension (for example, 2716 -march=armv8.2-a+sve). By default, the generated code works with 2717 all vector lengths, but it can be made specific to N-bit vectors 2718 using -msve-vector-bits=N. 2719 * Support has been added for the following processors (GCC 2720 identifiers in parentheses): 2721 + Arm Cortex-A75 (cortex-a75). 2722 + Arm Cortex-A55 (cortex-a55). 2723 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 2724 (cortex-a75.cortex-a55). 2725 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2726 options, for example: -mcpu=cortex-a75 or -mtune=cortex-a75 or as 2727 arguments to the equivalent target attributes and pragmas. 2728 2729 ARC 2730 2731 * Added support for: 2732 + Fast interrupts. 2733 + Naked functions. 2734 + aux variable attributes. 2735 + uncached type qualifier. 2736 + Secure functions via sjli instruction. 2737 * New exception handling implementation. 2738 * Revamped trampoline implementation. 2739 * Refactored small data feature implementation, controlled via -G 2740 command line option. 2741 * New support for reduced register set ARC architecture 2742 configurations, controlled via -mrf16 command line option. 2743 * Refurbished and improved support for zero overhead loops. 2744 Introduced -mlpc-width command line option to control the width of 2745 lp_count register. 2746 2747 ARM 2748 2749 * The -mfpu option now takes a new option setting of -mfpu=auto. When 2750 set to this the floating-point and SIMD settings are derived from 2751 the settings of the -mcpu or -march options. The internal CPU 2752 configurations have been updated with information about the 2753 permitted floating-point configurations supported. See the user 2754 guide for further information about the extended option syntax for 2755 controlling architectural extensions via the -march option. 2756 -mfpu=auto is now the default setting unless the compiler has been 2757 configured with an explicit --with-fpu option. 2758 * The -march and -mcpu options now accept optional extensions to the 2759 architecture or CPU option, allowing the user to enable or disable 2760 any such extensions supported by that architecture or CPU such as 2761 (but not limited to) floating-point and AdvancedSIMD. For example: 2762 the option -mcpu=cortex-a53+nofp will generate code for the 2763 Cortex-A53 processor with no floating-point support. This, in 2764 combination with the new -mfpu=auto option, provides a 2765 straightforward way of specifying a valid build target through a 2766 single -mcpu or -march option. The -mtune option accepts the same 2767 arguments as -mcpu but only the CPU name has an effect on tuning. 2768 The architecture extensions do not have any effect. For details of 2769 what extensions a particular architecture or CPU option supports 2770 please refer to the [23]documentation. 2771 * The -mstructure-size-boundary option has been deprecated and will 2772 be removed in a future release. 2773 * The default link behavior for Armv6 and Armv7-R targets has been 2774 changed to produce BE8 format when generating big-endian images. A 2775 new flag -mbe32 can be used to force the linker to produce legacy 2776 BE32 format images. There is no change of behavior for Armv6-M and 2777 other Armv7 or later targets: these already defaulted to BE8 2778 format. This change brings GCC into alignment with other compilers 2779 for the ARM architecture. 2780 * The Armv8-R architecture is now supported. It can be used by 2781 specifying the -march=armv8-r option. 2782 * The Armv8.3-A architecture is now supported. It can be used by 2783 specifying the -march=armv8.3-a option. 2784 * The Armv8.4-A architecture is now supported. It can be used by 2785 specifying the -march=armv8.4-a option. 2786 * The Dot Product instructions are now supported as an optional 2787 extension to the Armv8.2-A architecture and newer and are mandatory 2788 on Armv8.4-A. The extension can be used by specifying the +dotprod 2789 architecture extension. E.g. -march=armv8.2-a+dotprod. 2790 * Support for setting extensions and architectures using the GCC 2791 target pragma and attribute has been added. It can be used by 2792 specifying #pragma GCC target ("arch=..."), #pragma GCC target 2793 ("+extension"), __attribute__((target("arch=..."))) or 2794 __attribute__((target("+extension"))). 2795 * New Armv8.4-A FP16 Floating Point Multiplication Variant 2796 instructions have been added. These instructions are mandatory in 2797 Armv8.4-A but available as an optional extension to Armv8.2-A and 2798 Armv8.3-A. The new extension can be used by specifying the +fp16fml 2799 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 2800 the instructions can be enabled by specifying +fp16. 2801 * Support has been added for the following processors (GCC 2802 identifiers in parentheses): 2803 + Arm Cortex-A75 (cortex-a75). 2804 + Arm Cortex-A55 (cortex-a55). 2805 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 2806 (cortex-a75.cortex-a55). 2807 + Arm Cortex-R52 for Armv8-R (cortex-r52). 2808 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2809 options, for example: -mcpu=cortex-a75 or -mtune=cortex-r52 or as 2810 arguments to the equivalent target attributes and pragmas. 2811 2812 AVR 2813 2814 * The AVR port now supports the following XMEGA-like devices: 2815 2816 ATtiny212, ATtiny214, ATtiny412, ATtiny414, ATtiny416, ATtiny417, 2817 ATtiny814, ATtiny816, ATtiny817, ATtiny1614, ATtiny1616, ATtiny1617, 2818 ATtiny3214, ATtiny3216, ATtiny3217 2819 The new devices are listed under [24]-mmcu=avrxmega3. 2820 + These devices see flash memory in the RAM address space, so 2821 that features like PROGMEM and __flash are not needed any more 2822 (as opposed to other AVR families for which read-only data 2823 will be located in RAM except special, non-standard features 2824 are used to locate and access such data). This requires that 2825 the compiler is used with Binutils 2.29 or newer so that 2826 [25]read-only data will be located in flash memory. 2827 + A new command-line option -mshort-calls is supported. This 2828 option is used internally for multilib selection of the 2829 avrxmega3 variants. It is not an optimization option. Do not 2830 set it by hand. 2831 * The compiler now generates [26]efficient interrupt service routine 2832 (ISR) prologues and epilogues. This is achieved by using the new 2833 [27]AVR pseudo instruction __gcc_isr which is supported and 2834 resolved by the GNU assembler. 2835 + As the __gcc_isr pseudo-instruction will be resolved by the 2836 assembler, inline assembly is transparent to the process. This 2837 means that when inline assembly uses an instruction like INC 2838 that clobbers the condition code, then the assembler will 2839 detect this and generate an appropriate ISR prologue / 2840 epilogue chunk to save / restore SREG as needed. 2841 + A new command-line option -mno-gas-isr-prologues disables the 2842 generation of the __gcc_isr pseudo instruction. Any non-naked 2843 ISR will save and restore SREG, tmp_reg and zero_reg, no 2844 matter whether the respective register is clobbered or used. 2845 + The feature is turned on per default for all optimization 2846 levels except for -O0 and -Og. It is explicitly enabled by 2847 means of option -mgas-isr-prologues. 2848 + Support has been added for a new [28]AVR function attribute 2849 no_gccisr. It can be used to disable __gcc_isr pseudo 2850 instruction generation for individual ISRs. 2851 + This optimization is only available if GCC is configured with 2852 GNU Binutils 2.29 or newer; or at least with a version of 2853 Binutils that implements feature [29]PR21683. 2854 * The compiler no more saves / restores registers in main; the effect 2855 is the same as if attribute OS_task was specified for main. This 2856 optimization can be switched off by the new command-line option 2857 -mno-main-is-OS_task. 2858 2859 IA-32/x86-64 2860 2861 * The x86 port now supports the naked function attribute. 2862 * Better tuning for znver1 and Intel Core based CPUs. 2863 * Vectorization cost metrics has been reworked leading to significant 2864 improvements on some benchmarks. 2865 * GCC now supports the Intel CPU named Cannonlake through 2866 -march=cannonlake. The switch enables the AVX512VBMI, AVX512IFMA 2867 and SHA ISA extensions. 2868 * GCC now supports the Intel CPU named Icelake through 2869 -march=icelake. The switch enables the AVX512VNNI, GFNI, VAES, 2870 AVX512VBMI2, VPCLMULQDQ, AVX512BITALG, RDPID and AVX512VPOPCNTDQ 2871 ISA extensions. 2872 * GCC now supports the Intel Control-flow Enforcement Technology 2873 (CET) extension through -fcf-protection option. 2874 2875 NDS32 2876 2877 * New command-line options -mext-perf, -mext-perf2, and -mext-string 2878 have been added for performance extension instructions. 2879 2880 Nios II 2881 2882 * The Nios II back end has been improved to generate better-optimized 2883 code. Changes include switching to LRA, more accurate cost models, 2884 and more compact code for addressing static variables. 2885 * New command-line options -mgprel-sec= and -mr0rel-sec= have been 2886 added. 2887 * The stack-smashing protection options are now enabled on Nios II. 2888 2889 PA-RISC 2890 2891 * The default call ABI on 32-bit linux has been changed from callee 2892 copies to caller copies. This affects objects larger than eight 2893 bytes passed by value. The goal is to improve compatibility with 2894 x86 and resolve issues with OpenMP. 2895 * Other PA-RISC targets are unchanged. 2896 2897 PowerPC / PowerPC64 / RS6000 2898 2899 * The PowerPC SPE support is split off to a separate powerpcspe port. 2900 The separate port is deprecated and might be removed in a future 2901 release. 2902 * The Paired Single support (as used on some PPC750 CPUs, -mpaired, 2903 powerpc*-*-linux*paired*) is deprecated and will be removed in a 2904 future release. 2905 * The Xilinx floating point support (-mxilinx-fpu, 2906 powerpc-xilinx-eabi*) is deprecated and will be removed in a future 2907 release. 2908 * Support for using big-endian AltiVec intrinsics on a little-endian 2909 target (-maltivec=be) is deprecated and will be removed in a future 2910 release. 2911 2912 Tile 2913 2914 * The TILE-Gx port is deprecated and will be removed in a future 2915 release. 2916 2917 Operating Systems 2918 2919 Windows 2920 2921 * GCC on Microsoft Windows can now be configured via 2922 --enable-mingw-wildcard or --disable-mingw-wildcard to force a 2923 specific behavior for GCC itself with regards to supporting the 2924 wildcard character. Prior versions of GCC would follow the 2925 configuration of the MinGW runtime. This behavior can still be 2926 obtained by not using the above options or by using 2927 --enable-mingw-wildcard=platform. 2928 2929 Improvements for plugin authors 2930 2931 * Plugins can now register a callback hook for when comments are 2932 encountered by the C and C++ compilers, e.g. allowing for plugins 2933 to handle documentation markup in code comments. 2934 * The gdbinit support script for debugging GCC now has a 2935 break-on-diagnostic command, providing an easy way to trigger a 2936 breakpoint whenever a diagnostic is emitted. 2937 * The API for creating fix-it hints now supports newlines, and for 2938 emitting mutually incompatible fix-it hints for one diagnostic. 2939 2940 GCC 8.1 2941 2942 This is the [30]list of problem reports (PRs) from GCC's bug tracking 2943 system that are known to be fixed in the 8.1 release. This list might 2944 not be complete (that is, it is possible that some PRs that have been 2945 fixed are not listed here). 2946 2947 GCC 8.2 2948 2949 This is the [31]list of problem reports (PRs) from GCC's bug tracking 2950 system that are known to be fixed in the 8.2 release. This list might 2951 not be complete (that is, it is possible that some PRs that have been 2952 fixed are not listed here). 2953 2954 General Improvements 2955 2956 * Fixed LTO link-time performance problems caused by an overflow in 2957 the partitioning algorithm while building large binaries. 2958 2959 Language Specific Changes 2960 2961 C++ 2962 2963 GCC 8.2 fixed a bug introduced in GCC 8.1 affecting passing or 2964 returning of classes with a deleted copy constructor and defaulted 2965 trivial move constructor (bug [32]c++/86094). GCC 8.2 introduces 2966 -fabi-version=13 and makes it the default, ABI incompatibilities 2967 between GCC 8.1 and 8.2 can be reported with -Wabi=12. See [33]C++ 2968 changes for more details. 2969 2970 Target Specific Changes 2971 2972 IA-32/x86-64 2973 2974 * -mtune=native performance regression [34]PR84413 on Intel Skylake 2975 processors has been fixed. 2976 2977 GCC 8.3 2978 2979 This is the [35]list of problem reports (PRs) from GCC's bug tracking 2980 system that are known to be fixed in the 8.3 release. This list might 2981 not be complete (that is, it is possible that some PRs that have been 2982 fixed are not listed here). 2983 2984 Windows 2985 2986 * A C++ Microsoft ABI bitfield layout bug, [36]PR87137 has been 2987 fixed. A non-field declaration could cause the current bitfield 2988 allocation unit to be completed, incorrectly placing a following 2989 bitfield into a new allocation unit. The Microsoft ABI is selected 2990 for: 2991 + Mingw targets 2992 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 2993 option is specified, or __attribute__((ms_struct)) is used 2994 + SuperH targets when the -mhitachi option is specified, or 2995 __attribute__((renesas)) is used 2996 GCC 8 introduced additional cases of this defect, but rather than 2997 resolve only those regressions, we decided to resolve all the cases 2998 of this defect in single change. 2999 3000 GCC 8.4 3001 3002 This is the [37]list of problem reports (PRs) from GCC's bug tracking 3003 system that are known to be fixed in the 8.4 release. This list might 3004 not be complete (that is, it is possible that some PRs that have been 3005 fixed are not listed here). 3006 3007 GCC 8.5 3008 3009 This is the [38]list of problem reports (PRs) from GCC's bug tracking 3010 system that are known to be fixed in the 8.5 release. This list might 3011 not be complete (that is, it is possible that some PRs that have been 3012 fixed are not listed here). 3013 3014 Target Specific Changes 3015 3016 AArch64 3017 3018 * The option -moutline-atomics has been added to aid deployment of 3019 the Large System Extensions (LSE) on GNU/Linux systems built with a 3020 baseline architecture targeting Armv8-A. When the option is 3021 specified code is emitted to detect the presence of LSE 3022 instructions at run time and use them for standard atomic 3023 operations. For more information please refer to the documentation. 3024 3025 3026 For questions related to the use of GCC, please consult these web 3027 pages and the [39]GCC manuals. If that fails, the 3028 [40]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 3029 web pages and the development of GCC are welcome on our developer 3030 list at [41]gcc (a] gcc.gnu.org. All of [42]our lists have public 3031 archives. 3032 3033 Copyright (C) [43]Free Software Foundation, Inc. Verbatim copying and 3034 distribution of this entire article is permitted in any medium, 3035 provided this notice is preserved. 3036 3037 These pages are [44]maintained by the GCC team. Last modified 3038 2021-10-01[45]. 3039 3040 References 3041 3042 1. http://gcc.gnu.org/gcc-8/porting_to.html 3043 2. http://gcc.gnu.org/onlinedocs/index.html#current 3044 3. https://gcc.gnu.org/ml/gcc/2018-04/msg00102.html 3045 4. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmultistatement-macros 3046 5. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wstringop-truncation 3047 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944 3048 7. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wif-not-aligned 3049 8. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Common-Variable-Attributes.html#index-warn_005fif_005fnot_005faligned-variable-attribute 3050 9. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmissing-attributes 3051 10. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wpacked-not-aligned 3052 11. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Warray-bounds 3053 12. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wrestrict 3054 13. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-overflow 3055 14. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-truncation 3056 15. https://gcc.gnu.org/PR86094 3057 16. https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wclass-memaccess 3058 17. http://gcc.gnu.org/projects/cxx-status.html#cxx2a 3059 18. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_vector 3060 19. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/expressions.html#gcc_jit_context_new_rvalue_from_vector 3061 20. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_aligned 3062 21. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/function-pointers.html#gcc_jit_function_get_address 3063 22. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/contexts.html#gcc_jit_context_dump_reproducer_to_file 3064 23. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/ARM-Options.html#ARM-Options 3065 24. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Options.html 3066 25. https://sourceware.org/PR21472 3067 26. https://gcc.gnu.org/PR20296 3068 27. https://sourceware.org/binutils/docs-2.29/as/AVR-Pseudo-Instructions.html 3069 28. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Function-Attributes.html 3070 29. https://sourceware.org/PR21683 3071 30. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.0 3072 31. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.2 3073 32. https://gcc.gnu.org/PR86094 3074 33. http://gcc.gnu.org/gcc-8/changes.html#cxx 3075 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84413 3076 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.3 3077 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137 3078 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.4 3079 38. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.5 3080 39. https://gcc.gnu.org/onlinedocs/ 3081 40. mailto:gcc-help (a] gcc.gnu.org 3082 41. mailto:gcc (a] gcc.gnu.org 3083 42. https://gcc.gnu.org/lists.html 3084 43. https://www.fsf.org/ 3085 44. https://gcc.gnu.org/about.html 3086 45. http://validator.w3.org/check/referer 3087 ====================================================================== 3088 http://gcc.gnu.org/gcc-7/index.html 3089 GCC 7 Release Series 3090 3091 (This release series is no longer supported.) 3092 3093 Nov 14, 2019 3094 3095 The [1]GNU project and the GCC developers are pleased to announce the 3096 release of GCC 7.5. 3097 3098 This release is a bug-fix release, containing fixes for regressions in 3099 GCC 7.4 relative to previous releases of GCC. 3100 3101 Release History 3102 3103 GCC 7.5 3104 Nov 14, 2019 ([2]changes, [3]documentation) 3105 3106 GCC 7.4 3107 Dec 6, 2018 ([4]changes, [5]documentation) 3108 3109 GCC 7.3 3110 Jan 25, 2018 ([6]changes, [7]documentation) 3111 3112 GCC 7.2 3113 Aug 14, 2017 ([8]changes, [9]documentation) 3114 3115 GCC 7.1 3116 May 2, 2017 ([10]changes, [11]documentation) 3117 3118 References and Acknowledgements 3119 3120 GCC used to stand for the GNU C Compiler, but since the compiler 3121 supports several other languages aside from C, it now stands for the 3122 GNU Compiler Collection. 3123 3124 A list of [12]successful builds is updated as new information becomes 3125 available. 3126 3127 The GCC developers would like to thank the numerous people that have 3128 contributed new features, improvements, bug fixes, and other changes as 3129 well as test results to GCC. This [13]amazing group of volunteers is 3130 what makes GCC successful. 3131 3132 For additional information about GCC please refer to the [14]GCC 3133 project web site or contact the [15]GCC development mailing list. 3134 3135 To obtain GCC please use [16]our mirror sites or [17]our version 3136 control system. 3137 3138 3139 For questions related to the use of GCC, please consult these web 3140 pages and the [18]GCC manuals. If that fails, the 3141 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 3142 web pages and the development of GCC are welcome on our developer 3143 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 3144 archives. 3145 3146 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 3147 distribution of this entire article is permitted in any medium, 3148 provided this notice is preserved. 3149 3150 These pages are [23]maintained by the GCC team. Last modified 3151 2022-05-06[24]. 3152 3153 References 3154 3155 1. http://www.gnu.org/ 3156 2. http://gcc.gnu.org/gcc-7/changes.html 3157 3. http://gcc.gnu.org/onlinedocs/7.5.0/ 3158 4. http://gcc.gnu.org/gcc-7/changes.html 3159 5. http://gcc.gnu.org/onlinedocs/7.4.0/ 3160 6. http://gcc.gnu.org/gcc-7/changes.html 3161 7. http://gcc.gnu.org/onlinedocs/7.3.0/ 3162 8. http://gcc.gnu.org/gcc-7/changes.html 3163 9. http://gcc.gnu.org/onlinedocs/7.2.0/ 3164 10. http://gcc.gnu.org/gcc-7/changes.html 3165 11. http://gcc.gnu.org/onlinedocs/7.1.0/ 3166 12. http://gcc.gnu.org/gcc-7/buildstat.html 3167 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 3168 14. http://gcc.gnu.org/index.html 3169 15. mailto:gcc (a] gcc.gnu.org 3170 16. http://gcc.gnu.org/mirrors.html 3171 17. http://gcc.gnu.org/git.html 3172 18. https://gcc.gnu.org/onlinedocs/ 3173 19. mailto:gcc-help (a] gcc.gnu.org 3174 20. mailto:gcc (a] gcc.gnu.org 3175 21. https://gcc.gnu.org/lists.html 3176 22. https://www.fsf.org/ 3177 23. https://gcc.gnu.org/about.html 3178 24. http://validator.w3.org/check/referer 3179 ====================================================================== 3180 http://gcc.gnu.org/gcc-7/changes.html 3181 GCC 7 Release Series 3182 Changes, New Features, and Fixes 3183 3184 This page is a brief summary of some of the huge number of improvements 3185 in GCC 7. For more information, see the [1]Porting to GCC 7 page and 3186 the [2]full GCC documentation. 3187 3188 Caveats 3189 3190 * GCC now uses [3]LRA (a new local register allocator) by default for 3191 new targets. 3192 * The non-standard C++0x type traits has_trivial_default_constructor, 3193 has_trivial_copy_constructor and has_trivial_copy_assign have been 3194 removed. 3195 * The libstdc++ [4]Profile Mode has been deprecated and will be 3196 removed in a future version. 3197 * The Cilk+ extensions to the C and C++ languages have been 3198 deprecated. 3199 * On ARM targets (arm*-*-*), [5]a bug introduced in GCC 5 that 3200 affects conformance to the procedure call standard (AAPCS) has been 3201 fixed. The bug affects some C++ code where class objects are passed 3202 by value to functions and could result in incorrect or inconsistent 3203 code being generated. This is an ABI change. If the option -Wpsabi 3204 is enabled (on by default) the compiler will emit a diagnostic note 3205 for code that might be affected. 3206 3207 General Optimizer Improvements 3208 3209 * GCC 7 can determine the return value or range of return values of 3210 some calls to the sprintf family of functions and make it available 3211 to other optimization passes. Some calls to the snprintf function 3212 with a zero size argument can be folded into constants. This 3213 optimization is included in -O1 and can be selectively controlled 3214 by the -fprintf-return-value option. 3215 * A new store merging pass has been added. It merges constant stores 3216 to adjacent memory locations into fewer, wider, stores. It is 3217 enabled by the -fstore-merging option and at the -O2 optimization 3218 level or higher (and -Os). 3219 * A new code hoisting optimization has been added to the partial 3220 redundancy elimination pass. It attempts to move evaluation of 3221 expressions executed on all paths to the function exit as early as 3222 possible. This primarily helps improve code size, but can improve 3223 the speed of the generated code as well. It is enabled by the 3224 -fcode-hoisting option and at the -O2 optimization level or higher 3225 (and -Os). 3226 * A new interprocedural bitwise constant propagation optimization has 3227 been added, which propagates knowledge about which bits of 3228 variables are known to be zero (including pointer alignment 3229 information) across the call graph. It is enabled by the 3230 -fipa-bit-cp option if -fipa-cp is enabled as well, and is enabled 3231 at the -O2 optimization level and higher (and -Os). This 3232 optimization supersedes interprocedural alignment propagation of 3233 GCC 6, and therefore the option -fipa-cp-alignment is now 3234 deprecated and ignored. 3235 * A new interprocedural value range propagation optimization has been 3236 added, which propagates integral range information across the call 3237 graph when variable values can be proven to be within those ranges. 3238 It is enabled by the -fipa-vrp option and at the -O2 optimization 3239 level and higher (and -Os). 3240 * A new loop splitting optimization pass has been added. Certain 3241 loops which contain a condition that is always true on one side of 3242 the iteration space and always false on the other are split into 3243 two loops, such that each of the two new loops iterates on just one 3244 side of the iteration space and the condition does not need to be 3245 checked inside of the loop. It is enabled by the -fsplit-loops 3246 option and at the -O3 optimization level or higher. 3247 * The shrink-wrapping optimization can now separate portions of 3248 prologues and epilogues to improve performance if some of the work 3249 done traditionally by prologues and epilogues is not needed on 3250 certain paths. This is controlled by the -fshrink-wrap-separate 3251 option, enabled by default. It requires target support, which is 3252 currently only implemented in the PowerPC and AArch64 ports. 3253 * AddressSanitizer gained a new sanitization option, 3254 -fsanitize-address-use-after-scope, which enables sanitization of 3255 variables whose address is taken and used after a scope where the 3256 variable is defined: 3257 3258 int 3259 main (int argc, char **argv) 3260 { 3261 char *ptr; 3262 { 3263 char my_char; 3264 ptr = &my_char; 3265 } 3266 3267 *ptr = 123; 3268 return *ptr; 3269 } 3270 3271 ==28882==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffb8dba99 3272 0 at pc 0x0000004006d5 bp 0x7fffb8dba960 sp 0x7fffb8dba958 3273 WRITE of size 1 at 0x7fffb8dba990 thread T0 3274 #0 0x4006d4 in main /tmp/use-after-scope-1.c:10 3275 #1 0x7f9c71943290 in __libc_start_main (/lib64/libc.so.6+0x20290) 3276 #2 0x400739 in _start (/tmp/a.out+0x400739) 3277 3278 Address 0x7fffb8dba990 is located in stack of thread T0 at offset 32 in frame 3279 #0 0x40067f in main /tmp/use-after-scope-1.c:3 3280 3281 This frame has 1 object(s): 3282 [32, 33) 'my_char' <== Memory access at offset 32 is inside this variable 3283 3284 The option is enabled by default with -fsanitize=address and 3285 disabled by default with -fsanitize=kernel-address. Compared to the 3286 LLVM compiler, where the option already exists, the implementation 3287 in the GCC compiler has some improvements and advantages: 3288 + Complex uses of gotos and case labels are properly handled and 3289 should not report any false positive or false negatives. 3290 + C++ temporaries are sanitized. 3291 + Sanitization can handle invalid memory stores that are 3292 optimized out by the LLVM compiler when optimization is 3293 enabled. 3294 * The -fsanitize=signed-integer-overflow suboption of the 3295 UndefinedBehavior Sanitizer now diagnoses arithmetic overflows even 3296 on arithmetic operations with generic vectors. 3297 * Version 5 of the DWARF debugging information standard is supported 3298 through the -gdwarf-5 option. The DWARF version 4 debugging 3299 information remains the default until consumers of debugging 3300 information are adjusted. 3301 3302 New Languages and Language specific improvements 3303 3304 OpenACC support in C, C++, and Fortran continues to be maintained and 3305 improved. See the [6]OpenACC and [7]Offloading wiki pages for further 3306 information. 3307 3308 Ada 3309 3310 * On mainstream native platforms, Ada programs no longer require the 3311 stack to be made executable in order to run properly. 3312 3313 BRIG (HSAIL) 3314 3315 Support for processing BRIG 1.0 files was added in this release. BRIG 3316 is a binary format for HSAIL (Heterogeneous System Architecture 3317 Intermediate Language). The BRIG front end can be used for implementing 3318 HSAIL "finalizers" (compilation of HSAIL to a native ISA) for 3319 GCC-supported targets. An implementation of an HSAIL runtime library, 3320 libhsail-rt is also included. 3321 3322 C family 3323 3324 * New command-line options have been added for the C and C++ 3325 compilers: 3326 + -Wimplicit-fallthrough warns when a switch case falls through. 3327 This warning has five different levels. The compiler is able 3328 to parse a wide range of fallthrough comments, depending on 3329 the level. It also handles control-flow statements, such as 3330 ifs. It's possible to suppress the warning by either adding a 3331 fallthrough comment, or by using a null statement: 3332 __attribute__ ((fallthrough)); (C, C++), or [[fallthrough]]; 3333 (C++17), or [[gnu::fallthrough]]; (C++11/C++14). This warning 3334 is enabled by -Wextra. 3335 + -Wpointer-compare warns when a pointer is compared with a zero 3336 character constant. Such code is now invalid in C++11 and GCC 3337 rejects it. This warning is enabled by default. 3338 + -Wduplicated-branches warns when an if-else has identical 3339 branches. 3340 + -Wrestrict warns when an argument passed to a 3341 restrict-qualified parameter aliases with another argument. 3342 + -Wmemset-elt-size warns for memset calls, when the first 3343 argument references an array, and the third argument is a 3344 number equal to the number of elements of the array, but not 3345 the size of the array. This warning is enabled by -Wall. 3346 + -Wint-in-bool-context warns about suspicious uses of integer 3347 values where boolean values are expected. This warning is 3348 enabled by -Wall. 3349 + -Wswitch-unreachable warns when a switch statement has 3350 statements between the controlling expression and the first 3351 case label which will never be executed. This warning is 3352 enabled by default. 3353 + -Wexpansion-to-defined warns when defined is used outside #if. 3354 This warning is enabled by -Wextra or -Wpedantic. 3355 + -Wregister warns about uses of the register storage specifier. 3356 In C++17 this keyword has been removed and for C++17 this is a 3357 pedantic warning enabled by default. The warning is not 3358 emitted for the GNU Explicit Register Variables extension. 3359 + -Wvla-larger-than=N warns about unbounded uses of 3360 variable-length arrays, and about bounded uses of 3361 variable-length arrays whose bound can be larger than N bytes. 3362 + -Wduplicate-decl-specifier warns when a declaration has 3363 duplicate const, volatile, restrict or _Atomic specifier. This 3364 warning is enabled by -Wall. 3365 * GCC 6's C and C++ front ends were able to offer suggestions for 3366 misspelled field names: 3367 3368 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 3369 you mean 'color'? 3370 return ptr->colour; 3371 ^~~~~~ 3372 3373 GCC 7 greatly expands the scope of these suggestions. Firstly, it 3374 adds fix-it hints to such suggestions: 3375 3376 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 3377 you mean 'color'? 3378 return ptr->colour; 3379 ^~~~~~ 3380 color 3381 3382 The suggestions now cover many other things, such as misspelled 3383 function names: 3384 3385 spellcheck-identifiers.c:11:3: warning: implicit declaration of function 'gtk_wi 3386 dget_showall'; did you mean 'gtk_widget_show_all'? [-Wimplicit-function-declarat 3387 ion] 3388 gtk_widget_showall (w); 3389 ^~~~~~~~~~~~~~~~~~ 3390 gtk_widget_show_all 3391 3392 misspelled macro names and enum values: 3393 3394 spellcheck-identifiers.cc:85:11: error: 'MAX_ITEM' undeclared here (not in a fun 3395 ction); did you mean 'MAX_ITEMS'? 3396 int array[MAX_ITEM]; 3397 ^~~~~~~~ 3398 MAX_ITEMS 3399 3400 misspelled type names: 3401 3402 spellcheck-typenames.c:7:14: error: unknown type name 'singed'; did you mean 'si 3403 gned'? 3404 void test (singed char e); 3405 ^~~~~~ 3406 signed 3407 3408 and, in the C front end, named initializers: 3409 3410 test.c:7:20: error: 'struct s' has no member named 'colour'; did you mean 'color 3411 '? 3412 struct s test = { .colour = 3 }; 3413 ^~~~~~ 3414 color 3415 3416 * The preprocessor can now offer suggestions for misspelled 3417 directives, e.g.: 3418 3419 test.c:5:2: error:invalid preprocessing directive #endfi; did you mean #endif? 3420 #endfi 3421 ^~~~~ 3422 endif 3423 3424 * Warnings about format strings now underline the pertinent part of 3425 the string, and can offer suggested fixes. In some cases, the 3426 pertinent argument is underlined. 3427 3428 test.c:51:29: warning: format '%s' expects argument of type 'char *', but argume 3429 nt 3 has type 'int' [-Wformat=] 3430 printf ("foo: %d bar: %s baz: %d", 100, i + j, 102); 3431 ~^ ~~~~~ 3432 %d 3433 3434 * The new -Wdangling-else command-line option has been split out of 3435 -Wparentheses and warns about dangling else. 3436 * The -Wshadow warning has been split into three variants. 3437 -Wshadow=global warns for any shadowing. This is the default when 3438 using -Wshadow without any argument. -Wshadow=local only warns for 3439 a local variable shadowing another local variable or parameter. 3440 -Wshadow=compatible-local only warns for a local variable shadowing 3441 another local variable or parameter whose type is compatible (in 3442 C++ compatible means that the type of the shadowing variable can be 3443 converted to that of the shadowed variable). 3444 The following example shows the different kinds of shadow warnings: 3445 3446 enum operation { add, count }; 3447 struct container { int nr; }; 3448 3449 int 3450 container_count (struct container c, int count) 3451 { 3452 int r = 0; 3453 for (int count = 0; count > 0; count--) 3454 { 3455 struct container count = c; 3456 r += count.nr; 3457 } 3458 return r; 3459 } 3460 3461 -Wshadow=compatible-local will warn for the parameter being 3462 shadowed with the same type: 3463 3464 warn-test.c:8:12: warning: declaration of 'count' shadows a parameter [-Wshadow= 3465 compatible-local] 3466 for (int count = 0; count > 0; count--) 3467 ^~~~~ 3468 warn-test.c:5:42: note: shadowed declaration is here 3469 container_count (struct container c, int count) 3470 ^~~~~ 3471 3472 -Wshadow=local will warn for the above and for the shadowed 3473 declaration with incompatible type: 3474 3475 warn-test.c:10:24: warning: declaration of 'count' shadows a previous local [-Ws 3476 hadow=local] 3477 struct container count = c; 3478 ^~~~~ 3479 warn-test.c:8:12: note: shadowed declaration is here 3480 for (int count = 0; count > 0; count--) 3481 ^~~~~ 3482 3483 -Wshadow=global will warn for all of the above and the shadowing of 3484 the global declaration: 3485 3486 warn-test.c:5:42: warning: declaration of 'count' shadows a global declaration [ 3487 -Wshadow] 3488 container_count (struct container c, int count) 3489 ^~~~~ 3490 warn-test.c:1:23: note: shadowed declaration is here 3491 enum operation { add, count }; 3492 ^~~~~ 3493 3494 * GCC 7 contains a number of enhancements that help detect buffer 3495 overflow and other forms of invalid memory accesses. 3496 + The -Walloc-size-larger-than=size option detects calls to 3497 standard and user-defined memory allocation functions 3498 decorated with attribute alloc_size whose argument exceeds the 3499 specified size (PTRDIFF_MAX by default). The option also 3500 detects arithmetic overflow in the computation of the size in 3501 two-argument allocation functions like calloc where the total 3502 size is the product of the two arguments. Since calls with an 3503 excessive size cannot succeed they are typically the result of 3504 programming errors. Such bugs have been known to be the source 3505 of security vulnerabilities and a target of exploits. 3506 -Walloc-size-larger-than=PTRDIFF_MAX is included in -Wall. 3507 For example, the following call to malloc incorrectly tries to 3508 avoid passing a negative argument to the function and instead 3509 ends up unconditionally invoking it with an argument less than 3510 or equal to zero. Since after conversion to the type of the 3511 argument of the function (size_t) a negative argument results 3512 in a value in excess of the maximum PTRDIFF_MAX the call is 3513 diagnosed. 3514 3515 void* f (int n) 3516 { 3517 return malloc (n > 0 ? 0 : n); 3518 } 3519 3520 warning: argument 1 range [2147483648, 4294967295] exceeds maximum object size 2 3521 147483647 [-Walloc-size-larger-than=] 3522 3523 + The -Walloc-zero option detects calls to standard and 3524 user-defined memory allocation functions decorated with 3525 attribute alloc_size with a zero argument. -Walloc-zero is not 3526 included in either -Wall or -Wextra and must be explicitly 3527 enabled. 3528 + The -Walloca option detects all calls to the alloca function 3529 in the program. -Walloca is not included in either -Wall or 3530 -Wextra and must be explicitly enabled. 3531 + The -Walloca-larger-than=size option detects calls to the 3532 alloca function whose argument either may exceed the specified 3533 size, or that is not known to be sufficiently constrained to 3534 avoid exceeding it. -Walloca-larger-than is not included in 3535 either -Wall or -Wextra and must be explicitly enabled. 3536 For example, compiling the following snippet with 3537 -Walloca-larger-than=1024 results in a warning because even 3538 though the code appears to call alloca only with sizes of 1kb 3539 and less, since n is signed, a negative value would result in 3540 a call to the function well in excess of the limit. 3541 3542 void f (int n) 3543 { 3544 char *d; 3545 if (n < 1025) 3546 d = alloca (n); 3547 else 3548 d = malloc (n); 3549 3550 } 3551 3552 warning: argument to 'alloca may be too large due to conversion from 'int' to 'l 3553 ong unsigned int' [-Walloca-larger-than=] 3554 3555 In contrast, a call to alloca that isn't bounded at all such 3556 as in the following function will elicit the warning below 3557 regardless of the size argument to the option. 3558 3559 void f (size_t n) 3560 { 3561 char *d = alloca (n); 3562 3563 } 3564 3565 warning: unbounded use of 'alloca' [-Walloca-larger-than=] 3566 3567 + The -Wformat-overflow=level option detects certain and likely 3568 buffer overflow in calls to the sprintf family of formatted 3569 output functions. Although the option is enabled even without 3570 optimization it works best with -O2 and higher. 3571 For example, in the following snippet the call to sprintf is 3572 diagnosed because even though its output has been constrained 3573 using the modulo operation it could result in as many as three 3574 bytes if mday were negative. The solution is to either 3575 allocate a larger buffer or make sure the argument is not 3576 negative, for example by changing mday's type to unsigned or 3577 by making the type of the second operand of the modulo 3578 expression unsigned: 100U. 3579 3580 void* f (int mday) 3581 { 3582 char *buf = malloc (3); 3583 sprintf (buf, "%02i", mday % 100); 3584 return buf; 3585 } 3586 3587 warning: 'sprintf may write a terminating nul past the end of the destination [- 3588 Wformat-overflow=] 3589 note: 'sprintf' output between 3 and 4 bytes into a destination of size 3 3590 3591 + The -Wformat-truncation=level option detects certain and 3592 likely output truncation in calls to the snprintf family of 3593 formatted output functions. -Wformat-truncation=1 is included 3594 in -Wall and enabled without optimization but works best with 3595 -O2 and higher. 3596 For example, the following function attempts to format an 3597 integer between 0 and 255 in hexadecimal, including the 0x 3598 prefix, into a buffer of four characters. But since the 3599 function must always terminate output by the null character 3600 ('\0') such a buffer is only big enough to fit just one digit 3601 plus the prefix. Therefore the snprintf call is diagnosed. To 3602 avoid the warning either use a bigger buffer or handle the 3603 function's return value which indicates whether or not its 3604 output has been truncated. 3605 3606 void f (unsigned x) 3607 { 3608 char d[4]; 3609 snprintf (d, sizeof d, "%#02x", x & 0xff); 3610 3611 } 3612 3613 warning: 'snprintf' output may be truncated before the last format character [-W 3614 format-truncation=] 3615 note: 'snprintf' output between 3 and 5 bytes into a destination of size 4 3616 3617 + The -Wnonnull option has been enhanced to detect a broader set 3618 of cases of passing null pointers to functions that expect a 3619 non-null argument (those decorated with attribute nonnull). By 3620 taking advantage of optimizations the option can detect many 3621 more cases of the problem than in prior GCC versions. 3622 + The -Wstringop-overflow=type option detects buffer overflow in 3623 calls to string handling functions like memcpy and strcpy. The 3624 option relies on [8]Object Size Checking and has an effect 3625 similar to defining the _FORTIFY_SOURCE macro. 3626 -Wstringop-overflow=2 is enabled by default. 3627 For example, in the following snippet, because the call to 3628 strncat specifies a maximum that allows the function to write 3629 past the end of the destination, it is diagnosed. To correct 3630 the problem and avoid the overflow the function should be 3631 called with a size of at most sizeof d - strlen(d) - 1. 3632 3633 void f (const char *fname) 3634 { 3635 char d[8]; 3636 strncpy (d, "/tmp/", sizeof d); 3637 strncat (d, fname, sizeof d); 3638 3639 } 3640 3641 warning: specified bound 8 equals the size of the destination [-Wstringop-overfl 3642 ow=] 3643 3644 * The <limits.h> header provided by GCC defines macros such as 3645 INT_WIDTH for the width in bits of integer types, if 3646 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 3647 included. The <stdint.h> header defines such macros as SIZE_WIDTH 3648 and INTMAX_WIDTH for the width of some standard typedef names for 3649 integer types, again if __STDC_WANT_IEC_60559_BFP_EXT__ is defined 3650 before the header is included; note that GCC's implementation of 3651 this header is only used for freestanding compilations, not hosted 3652 compilations, on most systems. These macros come from ISO/IEC TS 3653 18661-1:2014. 3654 * The <float.h> header provided by GCC defines the macro 3655 CR_DECIMAL_DIG, from ISO/IEC TS 18661-1:2014, if 3656 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 3657 included. This represents the number of decimal digits for which 3658 conversions between decimal character strings and binary formats, 3659 in both directions, are correctly rounded, and currently has the 3660 value of UINTMAX_MAX on all systems, reflecting that GCC's 3661 compile-time conversions are correctly rounded for any number of 3662 digits. 3663 * New __builtin_add_overflow_p, __builtin_sub_overflow_p, 3664 __builtin_mul_overflow_p built-in functions have been added. These 3665 work similarly to their siblings without the _p suffix, but do not 3666 actually store the result of the arithmetics anywhere, just return 3667 whether the operation would overflow. Calls to these built-ins with 3668 integer constant arguments evaluate to integer constants 3669 expressions. 3670 For example, in the following, c is assigned the result of a * b 3671 only if the multiplication does not overflow, otherwise it is 3672 assigned the value zero. The multiplication is performed at 3673 compile-time and without triggering a -Woverflow warning. 3674 3675 enum { 3676 a = 12345678, 3677 b = 87654321, 3678 c = __builtin_mul_overflow_p (a, b, a) ? 0 : a * b 3679 }; 3680 3681 C 3682 3683 * The C front end now supports type names _FloatN for floating-point 3684 types with IEEE interchange formats and _FloatNx for floating-point 3685 types with IEEE extended formats. These type names come from 3686 ISO/IEC TS 18661-3:2015. 3687 The set of types supported depends on the target for which GCC is 3688 configured. Most targets support _Float32, _Float32x and _Float64. 3689 _Float128 is supported on targets where IEEE binary128 encoding was 3690 already supported as long double or __float128. _Float64x is 3691 supported on targets where a type with either binary128 or Intel 3692 extended precision format is available. 3693 Constants with these types are supported using suffixes fN, FN, fNx 3694 and FNx (e.g., 1.2f128 or 2.3F64x). Macros such as FLT128_MAX are 3695 defined in <float.h> if __STDC_WANT_IEC_60559_TYPES_EXT__ is 3696 defined before it is included. 3697 These new types are always distinct from each other and from float, 3698 double and long double, even if they have the same encoding. 3699 Complex types such as _Complex _Float128 are also supported. 3700 Type-generic built-in functions such as __builtin_isinf support the 3701 new types, and the following type-specific built-in functions have 3702 versions (suffixed fN or fNx) for the new types: 3703 __builtin_copysign, __builtin_fabs, __builtin_huge_val, 3704 __builtin_inf, __builtin_nan, __builtin_nans. 3705 * Compilation with -fopenmp is now compatible with the C11 _Atomic 3706 keyword. 3707 3708 C++ 3709 3710 * The C++ front end has experimental support for all of the current 3711 C++17 draft with the -std=c++1z or -std=gnu++1z flags, including if 3712 constexpr, class template argument deduction, auto template 3713 parameters, and structured bindings. For a full list of new 3714 features, see [9]the C++ status page. 3715 * C++17 support for new of over-aligned types can be enabled in other 3716 modes with the -faligned-new flag. 3717 * The C++17 evaluation order requirements can be selected in other 3718 modes with the -fstrong-eval-order flag, or disabled in C++17 mode 3719 with -fno-strong-eval-order. 3720 * The default semantics of inherited constructors has changed in all 3721 modes, following [10]P0136. Essentially, overload resolution 3722 happens as if calling the inherited constructor directly, and the 3723 compiler fills in construction of the other bases and members as 3724 needed. Most uses should not need any changes. The old behavior can 3725 be restored with -fno-new-inheriting-ctors, or -fabi-version less 3726 than 11. 3727 * The resolution of DR 150 on matching of template template 3728 parameters, allowing default template arguments to make a template 3729 match a parameter, is currently enabled by default in C++17 mode 3730 only. The default can be overridden with -f{no-,}new-ttp-matching. 3731 * The C++ front end will now provide fix-it hints for some missing 3732 semicolons, allowing for automatic fixes by IDEs: 3733 3734 test.cc:4:11: error: expected ';' after class definition 3735 class a {} 3736 ^ 3737 ; 3738 3739 * -Waligned-new has been added to the C++ front end. It warns about 3740 new of type with extended alignment without -faligned-new. 3741 3742 Runtime Library (libstdc++) 3743 3744 * The type of exception thrown by iostreams, std::ios_base::failure, 3745 now uses the [11]cxx11 ABI. 3746 * Experimental support for C++17, including the following new 3747 features: 3748 + std::string_view; 3749 + std::any, std::optional, and std::variant; 3750 + std::invoke, std::is_invocable, std::is_nothrow_invocable, and 3751 invoke_result; 3752 + std::is_swappable, and std::is_nothrow_swappable; 3753 + std::apply, and std::make_from_tuple; 3754 + std::void_t, std::bool_constant, std::conjunction, 3755 std::disjunction, and std::negation; 3756 + Variable templates for type traits; 3757 + Mathematical Special Functions; 3758 + std::chrono::floor, std::chrono::ceil, std::chrono::round, and 3759 std::chrono::abs; 3760 + std::clamp, std::gcd, std::lcm, 3-dimensional std::hypot; 3761 + std::scoped_lock, std::shared_mutex, 3762 std::atomic<T>::is_always_lock_free; 3763 + std::sample, std::default_searcher, std::boyer_moore_searcher 3764 and std::boyer_moore_horspool_searcher; 3765 + Extraction and re-insertion of map and set nodes, try_emplace 3766 members for maps, and functions for accessing containers 3767 std::size, std::empty, and std::data; 3768 + std::shared_ptr support for arrays, 3769 std::shared_ptr<T>::weak_type, 3770 std::enable_shared_from_this<T>::weak_from_this(), and 3771 std::owner_less<void>; 3772 + std::byte; 3773 + std::as_const, std::not_fn, 3774 std::has_unique_object_representations, constexpr 3775 std::addressof. 3776 Thanks to Daniel Krgler, Tim Shen, Edward Smith-Rowland, and Ville 3777 Voutilainen for work on the C++17 support. 3778 * A new power-of-two rehashing policy for use with the _Hashtable 3779 internals, thanks to Franois Dumont. 3780 3781 Fortran 3782 3783 * Support for a number of extensions for compatibility with legacy 3784 code with new flags: 3785 + -fdec-structure Support for DEC STRUCTURE and UNION 3786 + -fdec-intrinsic-ints Support for new integer intrinsics with 3787 B/I/J/K prefixes such as BABS, JIAND... 3788 + -fdec-math Support for additional math intrinsics, including 3789 COTAN and degree-valued trigonometric functions such as TAND, 3790 ASIND... 3791 + -fdec Enable the -fdec-* family of extensions. 3792 * New flag -finit-derived to allow default initialization of 3793 derived-type variables. 3794 * Improved DO loops with step equal to 1 or -1, generates faster code 3795 without a loop preheader. A new warning, -Wundefined-do-loop, warns 3796 when a loop iterates either to HUGE(i) (with step equal to 1), or 3797 to -HUGE(i) (with step equal to -1). Invalid behavior can be caught 3798 at run time with -fcheck=do enabled: 3799 3800 program test 3801 implicit none 3802 integer(1) :: i 3803 do i = -HUGE(i)+10, -HUGE(i)-1, -1 3804 print *, i 3805 end do 3806 end program test 3807 3808 At line 8 of file do_check_12.f90 3809 Fortran runtime error: Loop iterates infinitely 3810 3811 * Version 4.5 of the [12]OpenMP specification is now partially 3812 supported in the Fortran compiler; the largest missing item is 3813 structure element mapping. 3814 * User-defined derived-type input/output (UDTIO) is added. 3815 * Derived type coarrays with allocatable and pointer components are 3816 partially supported. 3817 * Non-constant stop codes and error stop codes (Fortran 2015 3818 feature). 3819 * Derived types with allocatable components of recursive type. 3820 * Intrinsic assignment to polymorphic variables. 3821 * Improved submodule support. 3822 * Improved diagnostics (polymorphic results in pure functions). 3823 * Coarray: Support for failed images (Fortan 2015 feature). 3824 3825 Go 3826 3827 * GCC 7 provides a complete implementation of the Go 1.8.1 user 3828 packages. 3829 * Compared to the Go 1.8.1 toolchain, the garbage collector is more 3830 conservative and less concurrent. 3831 * Escape analysis is available for experimental use via the 3832 -fgo-optimize-allocs option. The -fgo-debug-escape prints 3833 information useful for debugging escape analysis choices. 3834 3835 Java (GCJ) 3836 3837 The GCC Java front end and associated libjava runtime library have been 3838 removed from GCC. 3839 3840 libgccjit 3841 3842 The libgccjit API gained support for marking calls as requiring 3843 tail-call optimization via a new entry point: 3844 [13]gcc_jit_rvalue_set_bool_require_tail_call. 3845 3846 libgccjit performs numerous checks at the API boundary, but if these 3847 succeed, it previously ignored errors and other diagnostics emitted 3848 within the core of GCC, and treated the compile of a gcc_jit_context as 3849 having succeeded. As of GCC 7 it now ensures that if any diagnostics 3850 are emitted, they are visible from the libgccjit API, and that the the 3851 context is flagged as having failed. 3852 3853 New Targets and Target Specific Improvements 3854 3855 AArch64 3856 3857 * GCC has been updated to the latest revision of the procedure call 3858 standard (AAPCS64) to provide support for parameter passing when 3859 data types have been over-aligned. 3860 * The ARMv8.3-A architecture is now supported. It can be used by 3861 specifying the -march=armv8.3-a option. 3862 * The option -msign-return-address= is supported to enable return 3863 address protection using ARMv8.3-A Pointer Authentication 3864 Extensions. For more information on the arguments accepted by this 3865 option, please refer to [14]AArch64-Options. 3866 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 3867 Extensions are now supported. They can be used by specifying the 3868 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 3869 Floating-Point Extensions introduce new half-precision data 3870 processing floating-point instructions. 3871 * Support has been added for the following processors (GCC 3872 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), Broadcom 3873 Vulcan (vulcan), Cavium ThunderX CN81xx (thunderxt81), Cavium 3874 ThunderX CN83xx (thunderxt83), Cavium ThunderX CN88xx 3875 (thunderxt88), Cavium ThunderX CN88xx pass 1.x (thunderxt88p1), 3876 Cavium ThunderX 2 CN99xx (thunderx2t99), Qualcomm Falkor (falkor). 3877 The GCC identifiers can be used as arguments to the -mcpu or -mtune 3878 options, for example: -mcpu=cortex-a73 or -mtune=vulcan or as 3879 arguments to the equivalent target attributes and pragmas. 3880 3881 ARC 3882 3883 * Added support for ARC HS and ARC EM processors. 3884 * Added support for ARC EM variation found in Intel QuarkSE SoCs. 3885 * Added support for NPS400 ARC700 based CPUs. 3886 * Thread Local Storage is now supported by ARC CPUs. 3887 * Fixed errors for ARC600 when using 32x16 multiplier option. 3888 * Fixed PIE for ARC CPUs. 3889 * New CPU templates are supported via multilib. 3890 3891 ARM 3892 3893 * Support for the ARMv5 and ARMv5E architectures has been deprecated 3894 (which have no known implementations) and will be removed in a 3895 future GCC release. Note that ARMv5T, ARMv5TE and ARMv5TEJ 3896 architectures remain supported. The values armv5 and armv5e of 3897 -march are thus deprecated. 3898 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 3899 Extensions are now supported. They can be used by specifying the 3900 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 3901 Floating-Point Extensions introduce new half-precision data 3902 processing floating-point instructions. 3903 * The ARMv8-M architecture is now supported in its two architecture 3904 profiles: ARMv8-M Baseline and ARMv8-M Mainline with its DSP and 3905 Floating-Point Extensions. They can be used by specifying the 3906 -march=armv8-m.base, armv8-m.main or armv8-m.main+dsp options. 3907 * Support has been added for the following processors (GCC 3908 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), ARM 3909 Cortex-M23 (cortex-m23) and ARM Cortex-M33 (cortex-m33). The GCC 3910 identifiers can be used as arguments to the -mcpu or -mtune 3911 options, for example: -mcpu=cortex-a73 or -mtune=cortex-m33. 3912 * A new command-line option -mpure-code has been added. It does not 3913 allow constant data to be placed in code sections. This option is 3914 only available when generating non-PIC code for ARMv7-M targets. 3915 * Support for the ACLE Coprocessor Intrinsics has been added. This 3916 enables the generation of coprocessor instructions through the use 3917 of intrinsics such as cdp, ldc, and others. 3918 * The configure option --with-multilib-list now accepts the value 3919 rmprofile to build multilib libraries for a range of embedded 3920 targets. See our [15]installation instructions for details. 3921 3922 AVR 3923 3924 * On the reduced Tiny cores, the progmem [16]variable attribute is 3925 now properly supported. Respective read-only variables are located 3926 in flash memory in section .progmem.data. No special code is needed 3927 to access such variables; the compiler automatically adds an offset 3928 of 0x4000 to all addresses, which is needed to access variables in 3929 flash memory. As opposed to ordinary cores where it is sufficient 3930 to specify the progmem attribute with definitions, on the reduced 3931 Tiny cores the attribute also has to be specified with (external) 3932 declarations: 3933 3934 extern const int array[] __attribute__((__progmem__)); 3935 3936 int get_value2 (void) 3937 { 3938 /* Access via addresses array + 0x4004 and array + 0x4005. */ 3939 return array[2]; 3940 } 3941 3942 const int* get_address (unsigned idx) 3943 { 3944 /* Returns array + 0x4000 + 2 * idx. */ 3945 return &array[idx]; 3946 } 3947 3948 * A new command-line option -Wmisspelled-isr has been added. It turns 3949 off or turns into errors warnings that are reported for 3950 interrupt service routines (ISRs) which don't follow AVR-LibC's 3951 naming convention of prefixing ISR names with __vector. 3952 * __builtin_avr_nops(n) is a new [17]built-in function that inserts n 3953 NOP instructions into the instruction stream. n must be a value 3954 known at compile time. 3955 3956 IA-32/x86-64 3957 3958 * Support for the AVX-512 Fused Multiply Accumulation Packed Single 3959 precision (4FMAPS), AVX-512 Vector Neural Network Instructions Word 3960 variable precision (4VNNIW), AVX-512 Vector Population Count 3961 (VPOPCNTDQ) and Software Guard Extensions (SGX) ISA extensions has 3962 been added. 3963 3964 NVPTX 3965 3966 * OpenMP target regions can now be offloaded to NVidia PTX GPGPUs. 3967 See the [18]Offloading Wiki on how to configure it. 3968 3969 PowerPC / PowerPC64 / RS6000 3970 3971 * The PowerPC port now uses LRA by default. 3972 * GCC now diagnoses inline assembly that clobbers register r2. This 3973 has always been invalid code, and is no longer quietly tolerated. 3974 * The PowerPC port's support for ISA 3.0 (-mcpu=power9) has been 3975 enhanced to generate more of the new instructions by default, and 3976 to provide more built-in functions to generate code for other new 3977 instructions. 3978 * The configuration option --enable-gnu-indirect-function is now 3979 enabled by default on PowerPC GNU/Linux builds. 3980 * The PowerPC port will now allow 64-bit and 32-bit integer types to 3981 be allocated to the VSX vector registers (ISA 2.06 and above). In 3982 addition, on ISA 3.0, 16-bit and 8-bit integer types can be 3983 allocated in the vector registers. Previously, only 64-bit integer 3984 types were allowed in the traditional floating point registers. 3985 * New options -mstack-protector-guard=global, 3986 -mstack-protector-guard=tls, -mstack-protector-guard-reg=, and 3987 -mstack-protector-guard-offset= change how the stack protector gets 3988 the value to use as canary. 3989 3990 S/390, System z, IBM z Systems, IBM Z 3991 3992 * Support for the IBM z14 processor has been added. When using the 3993 -march=z14 option, the compiler will generate code making use of 3994 the new instructions introduced with the vector enhancement 3995 facility and the miscellaneous instruction extension facility 2. 3996 The -mtune=z14 option enables z14 specific instruction scheduling 3997 without making use of new instructions. 3998 * Builtins for the new vector instructions have been added and can be 3999 enabled using the -mzvector option. 4000 4001 RISC-V 4002 4003 * Support for the RISC-V instruction set has been added. 4004 4005 RX 4006 4007 Basic support for atomic built-in function has been added. It is 4008 currently implemented by flipping interrupts off and on as needed. 4009 4010 SH 4011 4012 * Support for SH5/SH64 has been removed. 4013 * Improved utilization of delay slots on SH2A. 4014 * Improved utilization of zero-displacement conditional branches. 4015 * The following deprecated options have been removed 4016 + -mcbranchdi 4017 + -mcmpeqdi 4018 + -minvalid-symbols 4019 + -msoft-atomic 4020 + -mspace 4021 + -madjust-unroll 4022 * Support for the following SH2A instructions has been added 4023 + mov.b @-Rm,R0 4024 + mov.w @-Rm,R0 4025 + mov.l @-Rm,R0 4026 + mov.b R0,@Rn+ 4027 + mov.w R0,@Rn+ 4028 + mov.l R0,@Rn+ 4029 4030 SPARC 4031 4032 * The SPARC port now uses LRA by default. 4033 * Support for the new Subtract-Extended-with-Carry instruction 4034 available in SPARC M7 (Niagara 7) has been added. 4035 4036 Operating Systems 4037 4038 AIX 4039 4040 * Visibility support has been enabled for AIX 7.1 and above. 4041 4042 Fuchsia 4043 4044 * Support has been added for the [19]Fuchsia OS. 4045 4046 RTEMS 4047 4048 * The ABI changes on ARM so that no short enums are used by default. 4049 4050 Other significant improvements 4051 4052 * -fverbose-asm previously emitted information on the meanings of 4053 assembly expressions. This has been extended so that it now also 4054 prints comments showing the source lines that correspond to the 4055 assembly, making it easier to read the generated assembly 4056 (especially with larger functions). For example, given this C 4057 source file: 4058 4059 int test (int n) 4060 { 4061 int i; 4062 int total = 0; 4063 4064 for (i = 0; i < n; i++) 4065 total += i * i; 4066 return total; 4067 } 4068 4069 -fverbose-asm now gives output similar to this for the function 4070 body (when compiling for x86_64, with -Os): 4071 4072 .text 4073 .globl test 4074 .type test, @@function 4075 test: 4076 .LFB0: 4077 .cfi_startproc 4078 # example.c:4: int total = 0; 4079 xorl %eax, %eax # <retval> 4080 # example.c:6: for (i = 0; i < n; i++) 4081 xorl %edx, %edx # i 4082 .L2: 4083 # example.c:6: for (i = 0; i < n; i++) 4084 cmpl %edi, %edx # n, i 4085 jge .L5 #, 4086 # example.c:7: total += i * i; 4087 movl %edx, %ecx # i, tmp92 4088 imull %edx, %ecx # i, tmp92 4089 # example.c:6: for (i = 0; i < n; i++) 4090 incl %edx # i 4091 # example.c:7: total += i * i; 4092 addl %ecx, %eax # tmp92, <retval> 4093 jmp .L2 # 4094 .L5: 4095 # example.c:10: } 4096 ret 4097 .cfi_endproc 4098 4099 * Two new options have been added for printing fix-it hints: 4100 + -fdiagnostics-parseable-fixits allows for fix-it hints to be 4101 emitted in a machine-readable form, suitable for consumption 4102 by IDEs. For example, given: 4103 4104 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 4105 you mean 'color'? 4106 return ptr->colour; 4107 ^~~~~~ 4108 color 4109 4110 it will emit: 4111 4112 fix-it:"spellcheck-fields.cc":{52:13-52:19}:"color" 4113 4114 + -fdiagnostics-generate-patch will print a patch in "unified" 4115 format after any diagnostics are printed, showing the result 4116 of applying all fix-it hints. For the above example it would 4117 emit: 4118 4119 --- spellcheck-fields.cc 4120 +++ spellcheck-fields.cc 4121 @@ -49,5 +49,5 @@ 4122 4123 color get_color(struct s *ptr) 4124 { 4125 - return ptr->colour; 4126 + return ptr->color; 4127 } 4128 4129 * The gcc and g++ driver programs will now provide suggestions for 4130 misspelled arguments to command-line options. 4131 4132 $ gcc -c test.c -ftls-model=global-dinamic 4133 gcc: error: unknown TLS model 'global-dinamic' 4134 gcc: note: valid arguments to '-ftls-model=' are: global-dynamic initial-exec lo 4135 cal-dynamic local-exec; did you mean 'global-dynamic'? 4136 4137 * The compiler will now provide suggestions for misspelled 4138 parameters. 4139 4140 $ gcc -c test.c --param max-early-inliner-iteration=3 4141 cc1: error: invalid --param name 'max-early-inliner-iteration'; did you mean 'ma 4142 x-early-inliner-iterations'? 4143 4144 * Profile-guided optimization (PGO) instrumentation, as well as test 4145 coverage (GCOV), can newly instrument constructors (functions marks 4146 with __attribute__((constructor))), destructors and C++ 4147 constructors (and destructors) of classes that are used as the type 4148 of a global variable. 4149 * A new option -fprofile-update=atomic prevents creation of corrupted 4150 profiles created during an instrumentation run (-fprofile=generate) 4151 of an application. The downside of the option is a speed penalty. 4152 Providing -pthread on the command line selects atomic profile 4153 updating (when supported by the target). 4154 * GCC's already extensive testsuite has gained some new capabilities, 4155 to further improve the reliability of the compiler: 4156 + GCC now has an internal unit-testing API and a suite of tests 4157 for programmatic self-testing of subsystems. 4158 + GCC's C front end has been extended so that it can parse dumps 4159 of GCC's internal representations, allowing for DejaGnu tests 4160 that more directly exercise specific optimization passes. This 4161 covers both the [20]GIMPLE representation (for testing 4162 higher-level optimizations) and the [21]RTL representation, 4163 allowing for more direct testing of lower-level details, such 4164 as register allocation and instruction selection. 4165 4166 GCC 7.1 4167 4168 This is the [22]list of problem reports (PRs) from GCC's bug tracking 4169 system that are known to be fixed in the 7.1 release. This list might 4170 not be complete (that is, it is possible that some PRs that have been 4171 fixed are not listed here). 4172 4173 GCC 7.2 4174 4175 This is the [23]list of problem reports (PRs) from GCC's bug tracking 4176 system that are known to be fixed in the 7.2 release. This list might 4177 not be complete (that is, it is possible that some PRs that have been 4178 fixed are not listed here). 4179 4180 Target Specific Changes 4181 4182 SPARC 4183 4184 * Support for the SPARC M8 processor has been added. 4185 * The switches -mfix-ut700 and -mfix-gr712rc have been added to work 4186 around an erratum in LEON3FT processors. 4187 * Use of the Floating-point Multiply Single to Double (FsMULd) 4188 instruction can now be controlled by the -mfsmuld and -fno-fsmuld 4189 options. 4190 4191 Operating Systems 4192 4193 RTEMS 4194 4195 * The Ada run-time support uses now thread-local storage (TLS). 4196 * Support for RISC-V has been added. 4197 * Support for 64-bit PowerPC using the ELFv2 ABI with 64-bit long 4198 double has been added. 4199 4200 GCC 7.3 4201 4202 This is the [24]list of problem reports (PRs) from GCC's bug tracking 4203 system that are known to be fixed in the 7.3 release. This list might 4204 not be complete (that is, it is possible that some PRs that have been 4205 fixed are not listed here). 4206 4207 Target Specific Changes 4208 4209 SPARC 4210 4211 * Workarounds for the four [25]LEON3FT errata GRLIB-TN-0010..0013 4212 have been added. Relevant errata are activated by the target 4213 specific -mfix-ut699, -mfix-ut700 and -mfix-gr712rc switches. 4214 4215 Operating Systems 4216 4217 RTEMS 4218 4219 * Support has been added for Epiphany target. 4220 4221 GCC 7.4 4222 4223 This is the [26]list of problem reports (PRs) from GCC's bug tracking 4224 system that are known to be fixed in the 7.4 release. This list might 4225 not be complete (that is, it is possible that some PRs that have been 4226 fixed are not listed here). 4227 4228 GCC 7.5 4229 4230 This is the [27]list of problem reports (PRs) from GCC's bug tracking 4231 system that are known to be fixed in the 7.5 release. This list might 4232 not be complete (that is, it is possible that some PRs that have been 4233 fixed are not listed here). 4234 4235 4236 For questions related to the use of GCC, please consult these web 4237 pages and the [28]GCC manuals. If that fails, the 4238 [29]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 4239 web pages and the development of GCC are welcome on our developer 4240 list at [30]gcc (a] gcc.gnu.org. All of [31]our lists have public 4241 archives. 4242 4243 Copyright (C) [32]Free Software Foundation, Inc. Verbatim copying and 4244 distribution of this entire article is permitted in any medium, 4245 provided this notice is preserved. 4246 4247 These pages are [33]maintained by the GCC team. Last modified 4248 2021-10-17[34]. 4249 4250 References 4251 4252 1. http://gcc.gnu.org/gcc-7/porting_to.html 4253 2. http://gcc.gnu.org/onlinedocs/index.html#current 4254 3. https://gcc.gnu.org/wiki/LRAIsDefault 4255 4. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/manual/profile_mode.html 4256 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728 4257 6. https://gcc.gnu.org/wiki/OpenACC 4258 7. https://gcc.gnu.org/wiki/Offloading 4259 8. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Object-Size-Checking.html 4260 9. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 4261 10. https://wg21.link/p0136 4262 11. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/using_dual_abi.html 4263 12. https://www.openmp.org/specifications/ 4264 13. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/jit/topics/expressions.html#gcc_jit_rvalue_set_bool_require_tail_call 4265 14. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AArch64-Options.html#AArch64-Options 4266 15. https://gcc.gnu.org/install/configure.html 4267 16. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Variable-Attributes.html 4268 17. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Built-in-Functions.html 4269 18. https://gcc.gnu.org/wiki/Offloading 4270 19. https://fuchsia.googlesource.com/ 4271 20. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/GIMPLE-Tests.html 4272 21. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/RTL-Tests.html 4273 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.0 4274 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.2 4275 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.3 4276 25. https://www.gaisler.com/index.php/information/app-tech-notes 4277 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.4 4278 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.5 4279 28. https://gcc.gnu.org/onlinedocs/ 4280 29. mailto:gcc-help (a] gcc.gnu.org 4281 30. mailto:gcc (a] gcc.gnu.org 4282 31. https://gcc.gnu.org/lists.html 4283 32. https://www.fsf.org/ 4284 33. https://gcc.gnu.org/about.html 4285 34. http://validator.w3.org/check/referer 4286 ====================================================================== 4287 http://gcc.gnu.org/gcc-6/index.html 4288 GCC 6 Release Series 4289 4290 (This release series is no longer supported.) 4291 4292 October 26, 2018 4293 4294 The [1]GNU project and the GCC developers are pleased to announce the 4295 release of GCC 6.5. 4296 4297 This release is a bug-fix release, containing fixes for regressions in 4298 GCC 6.4 relative to previous releases of GCC. 4299 4300 Release History 4301 4302 GCC 6.5 4303 October 26, 2018 ([2]changes, [3]documentation) 4304 4305 GCC 6.4 4306 July 4, 2017 ([4]changes, [5]documentation) 4307 4308 GCC 6.3 4309 December 21, 2016 ([6]changes, [7]documentation) 4310 4311 GCC 6.2 4312 August 22, 2016 ([8]changes, [9]documentation) 4313 4314 GCC 6.1 4315 April 27, 2016 ([10]changes, [11]documentation) 4316 4317 References and Acknowledgements 4318 4319 GCC used to stand for the GNU C Compiler, but since the compiler 4320 supports several other languages aside from C, it now stands for the 4321 GNU Compiler Collection. 4322 4323 A list of [12]successful builds is updated as new information becomes 4324 available. 4325 4326 The GCC developers would like to thank the numerous people that have 4327 contributed new features, improvements, bug fixes, and other changes as 4328 well as test results to GCC. This [13]amazing group of volunteers is 4329 what makes GCC successful. 4330 4331 For additional information about GCC please refer to the [14]GCC 4332 project web site or contact the [15]GCC development mailing list. 4333 4334 To obtain GCC please use [16]our mirror sites or [17]our version 4335 control system. 4336 4337 4338 For questions related to the use of GCC, please consult these web 4339 pages and the [18]GCC manuals. If that fails, the 4340 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 4341 web pages and the development of GCC are welcome on our developer 4342 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 4343 archives. 4344 4345 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 4346 distribution of this entire article is permitted in any medium, 4347 provided this notice is preserved. 4348 4349 These pages are [23]maintained by the GCC team. Last modified 4350 2021-07-28[24]. 4351 4352 References 4353 4354 1. http://www.gnu.org/ 4355 2. http://gcc.gnu.org/gcc-6/changes.html 4356 3. http://gcc.gnu.org/onlinedocs/6.5.0/ 4357 4. http://gcc.gnu.org/gcc-6/changes.html 4358 5. http://gcc.gnu.org/onlinedocs/6.4.0/ 4359 6. http://gcc.gnu.org/gcc-6/changes.html 4360 7. http://gcc.gnu.org/onlinedocs/6.3.0/ 4361 8. http://gcc.gnu.org/gcc-6/changes.html 4362 9. http://gcc.gnu.org/onlinedocs/6.2.0/ 4363 10. http://gcc.gnu.org/gcc-6/changes.html 4364 11. http://gcc.gnu.org/onlinedocs/6.1.0/ 4365 12. http://gcc.gnu.org/gcc-6/buildstat.html 4366 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 4367 14. http://gcc.gnu.org/index.html 4368 15. mailto:gcc (a] gcc.gnu.org 4369 16. http://gcc.gnu.org/mirrors.html 4370 17. http://gcc.gnu.org/git.html 4371 18. https://gcc.gnu.org/onlinedocs/ 4372 19. mailto:gcc-help (a] gcc.gnu.org 4373 20. mailto:gcc (a] gcc.gnu.org 4374 21. https://gcc.gnu.org/lists.html 4375 22. https://www.fsf.org/ 4376 23. https://gcc.gnu.org/about.html 4377 24. http://validator.w3.org/check/referer 4378 ====================================================================== 4379 http://gcc.gnu.org/gcc-6/changes.html 4380 GCC 6 Release Series 4381 Changes, New Features, and Fixes 4382 4383 This page is a brief summary of some of the huge number of improvements 4384 in GCC 6. For more information, see the [1]Porting to GCC 6 page and 4385 the [2]full GCC documentation. 4386 4387 Caveats 4388 4389 * The default mode for C++ is now -std=gnu++14 instead of 4390 -std=gnu++98. 4391 * Support for a number of older systems and recently unmaintained or 4392 untested target ports of GCC has been declared obsolete in GCC 6. 4393 Unless there is activity to revive them, the next release of GCC 4394 will have their sources permanently removed. 4395 The following ports for individual systems on particular 4396 architectures have been obsoleted: 4397 + SH5 / SH64 (sh64-*-*) as announced [3]here. 4398 * The AVR port requires binutils version 2.26.1 or later for the fix 4399 for [4]PR71151 to work. 4400 * The GCC 6.5 release has an accidental ABI incompatibility for 4401 nested std::pair objects, for more details see [5]PR 87822. The bug 4402 causes a layout change for pairs where the first member is also a 4403 pair, e.g. std::pair<std::pair<X, Y>, Z>. The GCC 6 release series 4404 is closed so the bug in GCC 6.5 will not be fixed upstream, but 4405 there is a patch in the bug report to allow it to be fixed by 4406 anybody packaging GCC 6.5 or installing it themselves. 4407 4408 General Optimizer Improvements 4409 4410 * UndefinedBehaviorSanitizer gained a new sanitization option, 4411 -fsanitize=bounds-strict, which enables strict checking of array 4412 bounds. In particular, it enables -fsanitize=bounds as well as 4413 instrumentation of flexible array member-like arrays. 4414 * Type-based alias analysis now disambiguates accesses to different 4415 pointers. This improves precision of the alias oracle by about 4416 20-30% on higher-level C++ programs. Programs doing invalid type 4417 punning of pointer types may now need -fno-strict-aliasing to work 4418 correctly. 4419 * Alias analysis now correctly supports the weakref and alias 4420 attributes. This allows accessing both a variable and its alias in 4421 one translation unit which is common with link-time optimization. 4422 * Value range propagation now assumes that the this pointer in C++ 4423 member functions is non-null. This eliminates common null pointer 4424 checks but also breaks some non-conforming code-bases (such as 4425 Qt-5, Chromium, KDevelop). As a temporary work-around 4426 -fno-delete-null-pointer-checks can be used. Wrong code can be 4427 identified by using -fsanitize=undefined. 4428 * Link-time optimization improvements: 4429 + warning and error attributes are now correctly preserved by 4430 declaration linking and thus -D_FORTIFY_SOURCE=2 is now 4431 supported with -flto. 4432 + Type merging was fixed to handle C and Fortran 4433 interoperability rules as defined by the Fortran 2008 language 4434 standard. 4435 As an exception, CHARACTER(KIND=C_CHAR) is not inter-operable 4436 with char in all cases because it is an array while char is 4437 scalar. INTEGER(KIND=C_SIGNED_CHAR) should be used instead. In 4438 general, this inter-operability cannot be implemented, for 4439 example on targets where the argument passing convention for 4440 arrays differs from scalars. 4441 + More type information is now preserved at link time, reducing 4442 the loss of accuracy of the type-based alias analysis compared 4443 to builds without link-time optimization. 4444 + Invalid type punning on global variables and declarations is 4445 now reported with -Wodr-type-mismatch. 4446 + The size of LTO object files was reduced by about 11% 4447 (measured by compiling Firefox 46.0). 4448 + Link-time parallelization (enabled using -flto=n) was 4449 significantly improved by decreasing the size of streamed data 4450 when partitioning programs. The size of streamed IL while 4451 compiling Firefox 46.0 was reduced by 66%. 4452 + The linker plugin was extended to pass information about the 4453 type of binary produced to the GCC back end. (That can also be 4454 controlled manually by -flinker-output.) This makes it 4455 possible to properly configure the code generator and support 4456 incremental linking. Incremental linking of LTO objects by gcc 4457 -r is now supported for plugin-enabled setups. 4458 There are two ways to perform incremental linking: 4459 1. Linking by ld -r will result in an object file with all 4460 sections from individual object files mechanically 4461 merged. This delays the actual link-time optimization to 4462 the final linking step and thus permits whole program 4463 optimization. Linking the final binary with such object 4464 files is however slower. 4465 2. Linking by gcc -r will lead to link-time optimization and 4466 emit the final binary into the object file. Linking such 4467 an object file is fast but avoids any benefits from whole 4468 program optimization. 4469 GCC 7 will support incremental link-time optimization with gcc 4470 -r. 4471 * Inter-procedural optimization improvements: 4472 + Basic jump threading is now performed before profile 4473 construction and inline analysis, resulting in more realistic 4474 size and time estimates that drive the heuristics of the 4475 inliner and function cloning passes. 4476 + Function cloning now more aggressively eliminates unused 4477 function parameters. 4478 4479 New Languages and Language specific improvements 4480 4481 Compared to GCC 5, the GCC 6 release series includes a much improved 4482 implementation of the [6]OpenACC 2.0a specification. Highlights are: 4483 * In addition to single-threaded host-fallback execution, offloading 4484 is supported for nvptx (Nvidia GPUs) on x86_64 and PowerPC 64-bit 4485 little-endian GNU/Linux host systems. For nvptx offloading, with 4486 the OpenACC parallel construct, the execution model allows for an 4487 arbitrary number of gangs, up to 32 workers, and 32 vectors. 4488 * Initial support for parallelized execution of OpenACC kernels 4489 constructs: 4490 + Parallelization of a kernels region is switched on by 4491 -fopenacc combined with -O2 or higher. 4492 + Code is offloaded onto multiple gangs, but executes with just 4493 one worker, and a vector length of 1. 4494 + Directives inside a kernels region are not supported. 4495 + Loops with reductions can be parallelized. 4496 + Only kernels regions with one loop nest are parallelized. 4497 + Only the outer-most loop of a loop nest can be parallelized. 4498 + Loop nests containing sibling loops are not parallelized. 4499 Typically, using the OpenACC parallel construct gives much better 4500 performance, compared to the initial support of the OpenACC kernels 4501 construct. 4502 * The device_type clause is not supported. The bind and nohost 4503 clauses are not supported. The host_data directive is not supported 4504 in Fortran. 4505 * Nested parallelism (cf. CUDA dynamic parallelism) is not supported. 4506 * Usage of OpenACC constructs inside multithreaded contexts (such as 4507 created by OpenMP, or pthread programming) is not supported. 4508 * If a call to the acc_on_device function has a compile-time constant 4509 argument, the function call evaluates to a compile-time constant 4510 value only for C and C++ but not for Fortran. 4511 4512 See the [7]OpenACC and [8]Offloading wiki pages for further 4513 information. 4514 4515 C family 4516 4517 * Version 4.5 of the [9]OpenMP specification is now supported in the 4518 C and C++ compilers. 4519 * The C and C++ compilers now support attributes on enumerators. For 4520 instance, it is now possible to mark enumerators as deprecated: 4521 4522 enum { 4523 newval, 4524 oldval __attribute__ ((deprecated ("too old"))) 4525 }; 4526 4527 * Source locations for the C and C++ compilers are now tracked as 4528 ranges, rather than just points, making it easier to identify the 4529 subexpression of interest within a complicated expression. For 4530 example: 4531 4532 test.cc: In function 'int test(int, int, foo, int, int)': 4533 test.cc:5:16: error: no match for 'operator*' (operand types are 'int' and 'foo' 4534 ) 4535 return p + q * r * s + t; 4536 ~~^~~ 4537 4538 In addition, there is now initial support for precise diagnostic 4539 locations within strings: 4540 4541 format-strings.c:3:14: warning: field width specifier '*' expects a matching 'in 4542 t' argument [-Wformat=] 4543 printf("%*d"); 4544 ^ 4545 4546 * Diagnostics can now contain "fix-it hints", which are displayed in 4547 context underneath the relevant source code. For example: 4548 4549 fixits.c: In function 'bad_deref': 4550 fixits.c:11:13: error: 'ptr' is a pointer; did you mean to use '->'? 4551 return ptr.x; 4552 ^ 4553 -> 4554 4555 * The C and C++ compilers now offer suggestions for misspelled field 4556 names: 4557 4558 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 4559 you mean 'color'? 4560 return ptr->colour; 4561 ^~~~~~ 4562 4563 * New command-line options have been added for the C and C++ 4564 compilers: 4565 + -Wshift-negative-value warns about left shifting a negative 4566 value. 4567 + -Wshift-overflow warns about left shift overflows. This 4568 warning is enabled by default. -Wshift-overflow=2 also warns 4569 about left-shifting 1 into the sign bit. 4570 + -Wtautological-compare warns if a self-comparison always 4571 evaluates to true or false. This warning is enabled by -Wall. 4572 + -Wnull-dereference warns if the compiler detects paths that 4573 trigger erroneous or undefined behavior due to dereferencing a 4574 null pointer. This option is only active when 4575 -fdelete-null-pointer-checks is active, which is enabled by 4576 optimizations in most targets. The precision of the warnings 4577 depends on the optimization options used. 4578 + -Wduplicated-cond warns about duplicated conditions in an 4579 if-else-if chain. 4580 + -Wmisleading-indentation warns about places where the 4581 indentation of the code gives a misleading idea of the block 4582 structure of the code to a human reader. For example, given 4583 [10]CVE-2014-1266: 4584 4585 sslKeyExchange.c: In function 'SSLVerifySignedServerKeyExchange': 4586 sslKeyExchange.c:629:3: warning: this 'if' clause does not guard... [-Wmisleadin 4587 g-indentation] 4588 if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0) 4589 ^~ 4590 sslKeyExchange.c:631:5: note: ...this statement, but the latter is misleadingly 4591 indented as if it is guarded by the 'if' 4592 goto fail; 4593 ^~~~ 4594 4595 This warning is enabled by -Wall. 4596 * The C and C++ compilers now emit saner error messages if 4597 merge-conflict markers are present in a source file. 4598 4599 test.c:3:1: error: version control conflict marker in file 4600 <<<<<<< HEAD 4601 ^~~~~~~ 4602 4603 C 4604 4605 * It is possible to disable warnings when an initialized field of a 4606 structure or a union with side effects is being overridden when 4607 using designated initializers via a new warning option 4608 -Woverride-init-side-effects. 4609 * A new type attribute scalar_storage_order applying to structures 4610 and unions has been introduced. It specifies the storage order (aka 4611 endianness) in memory of scalar fields in structures or unions. 4612 4613 C++ 4614 4615 * The default mode has been changed to -std=gnu++14. 4616 * [11]C++ Concepts are now supported when compiling with -fconcepts. 4617 * -flifetime-dse is more aggressive in dead-store elimination in 4618 situations where a memory store to a location precedes a 4619 constructor to that memory location. 4620 * G++ now supports [12]C++17 fold expressions, u8 character literals, 4621 extended static_assert, and nested namespace definitions. 4622 * G++ now allows constant evaluation for all non-type template 4623 arguments. 4624 * G++ now supports C++ Transactional Memory when compiling with 4625 -fgnu-tm. 4626 4627 Runtime Library (libstdc++) 4628 4629 * Extensions to the C++ Library to support mathematical special 4630 functions (ISO/IEC 29124:2010), thanks to Edward Smith-Rowland. 4631 * Experimental support for C++17, including the following new 4632 features: 4633 + std::uncaught_exceptions function (this is also available for 4634 -std=gnu++NN modes); 4635 + new member functions try_emplace and insert_or_assign for 4636 unique_key maps; 4637 + non-member functions std::size, std::empty, and std::data for 4638 accessing containers and arrays; 4639 + std::invoke; 4640 + std::shared_mutex; 4641 + std::void_t and std::bool_constant metaprogramming utilities. 4642 Thanks to Ville Voutilainen for contributing many of the C++17 4643 features. 4644 * An experimental implementation of the File System TS. 4645 * Experimental support for most features of the second version of the 4646 Library Fundamentals TS. This includes polymorphic memory resources 4647 and array support in shared_ptr, thanks to Fan You. 4648 * Some assertions checked by Debug Mode can now also be enabled by 4649 _GLIBCXX_ASSERTIONS. The subset of checks enabled by the new macro 4650 have less run-time overhead than the full _GLIBCXX_DEBUG checks and 4651 don't affect the library ABI, so can be enabled per-translation 4652 unit. 4653 * Timed mutex types are supported on more targets, including Darwin. 4654 * Improved std::locale support for DragonFly and FreeBSD, thanks to 4655 John Marino and Andreas Tobler. 4656 4657 Fortran 4658 4659 * Fortran 2008 SUBMODULE support. 4660 * Fortran 2015 EVENT_TYPE, EVENT_POST, EVENT_WAIT, and EVENT_QUERY 4661 support. 4662 * Improved support for Fortran 2003 deferred-length character 4663 variables. 4664 * Improved support for OpenMP and OpenACC. 4665 * The MATMUL intrinsic is now inlined for straightforward cases if 4666 front-end optimization is active. The maximum size for inlining can 4667 be set to n with the -finline-matmul-limit=n option and turned off 4668 with -finline-matmul-limit=0. 4669 * The -Wconversion-extra option will warn about REAL constants which 4670 have excess precision for their kind. 4671 * The -Winteger-division option has been added, which warns about 4672 divisions of integer constants which are truncated. This option is 4673 included in -Wall by default. 4674 4675 libgccjit 4676 4677 * The driver code is now run in-process within libgccjit, providing a 4678 small speed-up of the compilation process. 4679 * The API has gained entrypoints for 4680 + [13]timing how long was spent in different parts of code, 4681 + [14]creating switch statements, 4682 + [15]allowing unreachable basic blocks in a function, and 4683 + [16]adding arbitrary command-line options to a compilation. 4684 4685 New Targets and Target Specific Improvements 4686 4687 AArch64 4688 4689 * A number of AArch64-specific options have been added. The most 4690 important ones are summarised in this section; for more detailed 4691 information please refer to the documentation. 4692 * The command-line options -march=native, -mcpu=native and 4693 -mtune=native are now available on native AArch64 GNU/Linux 4694 systems. Specifying these options causes GCC to auto-detect the 4695 host CPU and choose the optimal setting for that system. 4696 * -fpic is now supported when generating code for the small code 4697 model (-mcmodel=small). The size of the global offset table (GOT) 4698 is limited to 28KiB under the LP64 SysV ABI, and 15KiB under the 4699 ILP32 SysV ABI. 4700 * The AArch64 port now supports target attributes and pragmas. Please 4701 refer to the [17]documentation for details of available attributes 4702 and pragmas as well as usage instructions. 4703 * Link-time optimization across translation units with different 4704 target-specific options is now supported. 4705 * The option -mtls-size= is now supported. It can be used to specify 4706 the bit size of TLS offsets, allowing GCC to generate better TLS 4707 instruction sequences. 4708 * The option -fno-plt is now fully functional. 4709 * The ARMv8.1-A architecture and the Large System Extensions are now 4710 supported. They can be used by specifying the -march=armv8.1-a 4711 option. Additionally, the +lse option extension can be used in a 4712 similar fashion to other option extensions. The Large System 4713 Extensions introduce new instructions that are used in the 4714 implementation of atomic operations. 4715 * The ACLE half-precision floating-point type __fp16 is now supported 4716 in the C and C++ languages. 4717 * The ARM Cortex-A35 processor is now supported via the 4718 -mcpu=cortex-a35 and -mtune=cortex-a35 options as well as the 4719 equivalent target attributes and pragmas. 4720 * The Qualcomm QDF24xx processor is now supported via the 4721 -mcpu=qdf24xx and -mtune=qdf24xx options as well as the equivalent 4722 target attributes and pragmas. 4723 * Code generation for the ARM Cortex-A57 processor is improved. Among 4724 general code generation improvements, a better algorithm is added 4725 for allocating registers to floating-point multiply-accumulate 4726 instructions offering increased performance when compiling with 4727 -mcpu=cortex-a57 or -mtune=cortex-a57. 4728 * Code generation for the ARM Cortex-A53 processor is improved. A 4729 more accurate instruction scheduling model for the processor is now 4730 used, and a number of compiler tuning parameters have been set to 4731 offer increased performance when compiling with -mcpu=cortex-a53 or 4732 -mtune=cortex-a53. 4733 * Code generation for the Samsung Exynos M1 processor is improved. A 4734 more accurate instruction scheduling model for the processor is now 4735 used, and a number of compiler tuning parameters have been set to 4736 offer increased performance when compiling with -mcpu=exynos-m1 or 4737 -mtune=exynos-m1. 4738 * Improvements in the generation of conditional branches and literal 4739 pools allow the compiler to compile functions of a large size. 4740 Constant pools are now placed into separate rodata sections. The 4741 new option -mpc-relative-literal-loads generates per-function 4742 literal pools, limiting the maximum size of functions to 1MiB. 4743 * Several correctness issues generating Advanced SIMD instructions 4744 for big-endian targets have been fixed resulting in improved code 4745 generation for ACLE intrinsics with -mbig-endian. 4746 4747 ARM 4748 4749 * Support for revisions of the ARM architecture prior to ARMv4t has 4750 been deprecated and will be removed in a future GCC release. The 4751 -mcpu and -mtune values that are deprecated are: arm2, arm250, 4752 arm3, arm6, arm60, arm600, arm610, arm620, arm7, arm7d, arm7di, 4753 arm70, arm700, arm700i, arm710, arm720, arm710c, arm7100, arm7500, 4754 arm7500fe, arm7m, arm7dm, arm7dmi, arm8, arm810, strongarm, 4755 strongarm110, strongarm1100, strongarm1110, fa526, fa626. The value 4756 arm7tdmi is still supported. The values of -march that are 4757 deprecated are: armv2,armv2a,armv3,armv3m,armv4. 4758 * The ARM port now supports target attributes and pragmas. Please 4759 refer to the [18]documentation for details of available attributes 4760 and pragmas as well as usage instructions. 4761 * Support has been added for the following processors (GCC 4762 identifiers in parentheses): ARM Cortex-A32 (cortex-a32), ARM 4763 Cortex-A35 (cortex-a35) and ARM Cortex-R8 (cortex-r8). The GCC 4764 identifiers can be used as arguments to the -mcpu or -mtune 4765 options, for example: -mcpu=cortex-a32 or -mtune=cortex-a35. 4766 4767 Heterogeneous Systems Architecture 4768 4769 * GCC can now generate HSAIL (Heterogeneous System Architecture 4770 Intermediate Language) for simple OpenMP device constructs if 4771 configured with --enable-offload-targets=hsa. A new libgomp plugin 4772 then runs the HSA GPU kernels implementing these constructs on HSA 4773 capable GPUs via a standard HSA run time. 4774 If the HSA compilation back end determines it cannot output HSAIL 4775 for a particular input, it gives a warning by default. These 4776 warnings can be suppressed with -Wno-hsa. To give a few examples, 4777 the HSA back end does not implement compilation of code using 4778 function pointers, automatic allocation of variable sized arrays, 4779 functions with variadic arguments as well as a number of other less 4780 common programming constructs. 4781 When compilation for HSA is enabled, the compiler attempts to 4782 compile composite OpenMP constructs 4783 4784 #pragma omp target teams distribute parallel for 4785 4786 into parallel HSA GPU kernels. 4787 4788 IA-32/x86-64 4789 4790 * GCC now supports the Intel CPU named Skylake with AVX-512 4791 extensions through -march=skylake-avx512. The switch enables the 4792 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 4793 AVX-512DQ. 4794 * Support for new AMD instructions monitorx and mwaitx has been 4795 added. This includes new intrinsic and built-in support. It is 4796 enabled through option -mmwaitx. The instructions monitorx and 4797 mwaitx implement the same functionality as the old monitor and 4798 mwait instructions. In addition mwaitx adds a configurable timer. 4799 The timer value is received as third argument and stored in 4800 register %ebx. 4801 * x86-64 targets now allow stack realignment from a word-aligned 4802 stack pointer using the command-line option -mstackrealign or 4803 __attribute__ ((force_align_arg_pointer)). This allows functions 4804 compiled with a vector-aligned stack to be invoked from objects 4805 that keep only word-alignment. 4806 * Support for address spaces __seg_fs, __seg_gs, and __seg_tls. These 4807 can be used to access data via the %fs and %gs segments without 4808 having to resort to inline assembly. Please refer to the 4809 [19]documentation for usage instructions. 4810 * Support for AMD Zen (family 17h) processors is now available 4811 through the -march=znver1 and -mtune=znver1 options. 4812 4813 MeP 4814 4815 * Support for the MeP (mep-elf) architecture has been deprecated and 4816 will be removed in a future GCC release. 4817 4818 MSP430 4819 4820 * The MSP430 compiler now has the ability to automatically distribute 4821 code and data between low memory (addresses below 64K) and high 4822 memory. This only applies to parts that actually have both memory 4823 regions and only if the linker script for the part has been 4824 specifically set up to support this feature. 4825 A new attribute of either can be applied to both functions and 4826 data, and this tells the compiler to place the object into low 4827 memory if there is room and into high memory otherwise. Two other 4828 new attributes - lower and upper - can be used to explicitly state 4829 that an object should be placed in the specified memory region. If 4830 there is not enough left in that region the compilation will fail. 4831 Two new command-line options - -mcode-region=[lower|upper|either] 4832 and -mdata-region=[lower|upper|either] - can be used to tell the 4833 compiler what to do with objects that do not have one of these new 4834 attributes. 4835 4836 PowerPC / PowerPC64 / RS6000 4837 4838 * PowerPC64 now supports IEEE 128-bit floating-point using the 4839 __float128 data type. In GCC 6, this is not enabled by default, but 4840 you can enable it with -mfloat128. The IEEE 128-bit floating-point 4841 support requires the use of the VSX instruction set. IEEE 128-bit 4842 floating-point values are passed and returned as a single vector 4843 value. The software emulator for IEEE 128-bit floating-point 4844 support is only built on PowerPC GNU/Linux systems where the 4845 default CPU is at least power7. On future ISA 3.0 systems (POWER 9 4846 and later), you will be able to use the -mfloat128-hardware option 4847 to use the ISA 3.0 instructions that support IEEE 128-bit 4848 floating-point. An additional type (__ibm128) has been added to 4849 refer to the IBM extended double type that normally implements long 4850 double. This will allow for a future transition to implementing 4851 long double with IEEE 128-bit floating-point. 4852 * Basic support has been added for POWER9 hardware that will use the 4853 recently published OpenPOWER ISA 3.0 instructions. The following 4854 new switches are available: 4855 + -mcpu=power9: Implement all of the ISA 3.0 instructions 4856 supported by the compiler. 4857 + -mtune=power9: In the future, apply tuning for POWER9 systems. 4858 Currently, POWER8 tunings are used. 4859 + -mmodulo: Generate code using the ISA 3.0 integer instructions 4860 (modulus, count trailing zeros, array index support, integer 4861 multiply/add). 4862 + -mpower9-fusion: Generate code to suitably fuse instruction 4863 sequences for a POWER9 system. 4864 + -mpower9-dform: Generate code to use the new D-form 4865 (register+offset) memory instructions for the vector 4866 registers. 4867 + -mpower9-vector: Generate code using the new ISA 3.0 vector 4868 (VSX or Altivec) instructions. 4869 + -mpower9-minmax: Reserved for future development. 4870 + -mtoc-fusion: Keep TOC entries together to provide more fusion 4871 opportunities. 4872 * New constraints have been added to support IEEE 128-bit 4873 floating-point and ISA 3.0 instructions: 4874 + wb: Altivec register if -mpower9-dform is enabled. 4875 + we: VSX register if -mpower9-vector is enabled for 64-bit code 4876 generation. 4877 + wo: VSX register if -mpower9-vector is enabled. 4878 + wp: Reserved for future use if long double is implemented with 4879 IEEE 128-bit floating-point instead of IBM extended double. 4880 + wq: VSX register if -mfloat128 is enabled. 4881 + wF: Memory operand suitable for POWER9 fusion load/store. 4882 + wG: Memory operand suitable for TOC fusion memory references. 4883 + wL: Integer constant identifying the element number mfvsrld 4884 accesses within a vector. 4885 * Support has been added for __builtin_cpu_is() and 4886 __builtin_cpu_supports(), allowing for very fast access to 4887 AT_PLATFORM, AT_HWCAP, and AT_HWCAP2 values. This requires use of 4888 glibc 2.23 or later. 4889 * All hardware transactional memory builtins now correctly behave as 4890 memory barriers. Programmers can use #ifdef __TM_FENCE__ to 4891 determine whether their "old" compiler treats the builtins as 4892 barriers. 4893 * Split-stack support has been added for gccgo on PowerPC64 for both 4894 big- and little-endian (but not for 32-bit). The gold linker from 4895 at least binutils 2.25.1 must be available in the PATH when 4896 configuring and building gccgo to enable split stack. (The 4897 requirement for binutils 2.25.1 applies to PowerPC64 only.) The 4898 split-stack feature allows a small initial stack size to be 4899 allocated for each goroutine, which increases as needed. 4900 * GCC on PowerPC now supports the standard lround function. 4901 * A new configuration option ---with-advance-toolchain=at was added 4902 for PowerPC 64-bit GNU/Linux systems to use the header files, 4903 library files, and the dynamic linker from a specific Advance 4904 Toolchain release instead of the default versions that are provided 4905 by the GNU/Linux distribution. In general, this option is intended 4906 for the developers of GCC, and it is not intended for general use. 4907 * The "q", "S", "T", and "t" asm-constraints have been removed. 4908 * The "b", "B", "m", "M", and "W" format modifiers have been removed. 4909 4910 S/390, System z, IBM z Systems 4911 4912 * Support for the IBM z13 processor has been added. When using the 4913 -march=z13 option, the compiler will generate code making use of 4914 the new instructions and registers introduced with the vector 4915 extension facility. The -mtune=z13 option enables z13 specific 4916 instruction scheduling without making use of new instructions. 4917 Compiling code with -march=z13 reduces the default alignment of 4918 vector types bigger than 8 bytes to 8. This is an ABI change and 4919 care must be taken when linking modules compiled with different 4920 arch levels which interchange variables containing vector type 4921 values. For newly compiled code the GNU linker will emit a warning. 4922 * The -mzvector option enables a C/C++ language extension. This 4923 extension provides a new keyword vector which can be used to define 4924 vector type variables. (Note: This is not available when enforcing 4925 strict standard compliance e.g. with -std=c99. Either enable GNU 4926 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 4927 Additionally a set of overloaded builtins is provided which is 4928 partially compatible to the PowerPC Altivec builtins. In order to 4929 make use of these builtins the vecintrin.h header file needs to be 4930 included. 4931 * The new command-line options -march=native, and -mtune=native are 4932 now available on native IBM z Systems. Specifying these options 4933 causes GCC to auto-detect the host CPU and choose the optimal 4934 setting for that system. If GCC is unable to detect the host CPU 4935 these options have no effect. 4936 * The IBM z Systems port now supports target attributes and pragmas. 4937 Please refer to the [20]documentation for details of available 4938 attributes and pragmas as well as usage instructions. 4939 * -fsplit-stack is now supported as part of the IBM z Systems port. 4940 This feature requires a recent gold linker to be used. 4941 * Support for the g5 and g6 -march=/-mtune= CPU level switches has 4942 been deprecated and will be removed in a future GCC release. -m31 4943 from now on defaults to -march=z900 if not specified otherwise. 4944 -march=native on a g5/g6 machine will default to -march=z900. 4945 4946 SH 4947 4948 * Support for SH5 / SH64 has been declared obsolete and will be 4949 removed in future releases. 4950 * Support for the FDPIC ABI has been added. It can be enabled using 4951 the new -mfdpic target option and --enable-fdpic configure option. 4952 4953 SPARC 4954 4955 * An ABI bug has been fixed in 64-bit mode. Unfortunately, this 4956 change will break binary compatibility with earlier releases for 4957 code it affects, but this should be pretty rare in practice. The 4958 conditions are: a 16-byte structure containing a double or a 8-byte 4959 vector in the second half is passed to a subprogram in slot #15, 4960 for example as 16th parameter if the first 15 ones have at most 8 4961 bytes. The double or vector was wrongly passed in floating-point 4962 register %d32 in lieu of on the stack as per the SPARC calling 4963 conventions. 4964 4965 Operating Systems 4966 4967 AIX 4968 4969 * DWARF debugging support for AIX 7.1 has been enabled as an optional 4970 debugging format. A more recent Technology Level (TL) and GCC built 4971 with that level are required for full exploitation of DWARF 4972 debugging capabilities. 4973 4974 Linux 4975 4976 * Support for the [21]musl C library was added for the AArch64, ARM, 4977 MicroBlaze, MIPS, MIPS64, PowerPC, PowerPC64, SH, i386, x32 and 4978 x86_64 targets. It can be selected using the new -mmusl option in 4979 case musl is not the default libc. GCC defaults to musl libc if it 4980 is built with a target triplet matching the *-linux-musl* pattern. 4981 4982 RTEMS 4983 4984 * The RTEMS thread model implementation changed. Mutexes now use 4985 self-contained objects defined in Newlib <sys/lock.h> instead of 4986 Classic API semaphores. The keys for thread specific data and the 4987 once function are directly defined via <pthread.h>. Self-contained 4988 condition variables are provided via Newlib <sys/lock.h>. The RTEMS 4989 thread model also supports C++11 threads. 4990 * OpenMP support now uses self-contained objects provided by Newlib 4991 <sys/lock.h> and offers a significantly better performance compared 4992 to the POSIX configuration of libgomp. It is possible to configure 4993 thread pools for each scheduler instance via the environment 4994 variable GOMP_RTEMS_THREAD_POOLS. 4995 4996 Solaris 4997 4998 * Solaris 12 is now fully supported. Minimal support had already been 4999 present in GCC 5.3. 5000 * Solaris 12 provides a full set of startup files (crt1.o, crti.o, 5001 crtn.o), which GCC now prefers over its own ones. 5002 * Position independent executables (PIE) are now supported on Solaris 5003 12. 5004 * Constructor priority is now supported on Solaris 12 with the system 5005 linker. 5006 * libvtv has been ported to Solaris 11 and up. 5007 5008 Windows 5009 5010 * The option -mstackrealign is now automatically activated in 32-bit 5011 mode whenever the use of SSE instructions is requested. 5012 5013 Other significant improvements 5014 5015 * The gcc and g++ driver programs will now provide suggestions for 5016 misspelled command-line options. 5017 5018 $ gcc -static-libfortran test.f95 5019 gcc: error: unrecognized command line option '-static-libfortran'; did you mean 5020 '-static-libgfortran'? 5021 5022 * The --enable-default-pie configure option enables generation of PIE 5023 by default. 5024 5025 GCC 6.2 5026 5027 This is the [22]list of problem reports (PRs) from GCC's bug tracking 5028 system that are known to be fixed in the 6.2 release. This list might 5029 not be complete (that is, it is possible that some PRs that have been 5030 fixed are not listed here). 5031 5032 Target Specific Changes 5033 5034 SPARC 5035 5036 * Support for --with-cpu-32 and --with-cpu-64 configure options has 5037 been added on bi-architecture platforms. 5038 * Support for the SPARC M7 (Niagara 7) processor has been added. 5039 * Support for the VIS 4.0 instruction set has been added. 5040 5041 GCC 6.3 5042 5043 This is the [23]list of problem reports (PRs) from GCC's bug tracking 5044 system that are known to be fixed in the 6.3 release. This list might 5045 not be complete (that is, it is possible that some PRs that have been 5046 fixed are not listed here). 5047 5048 Target Specific Changes 5049 5050 IA-32/x86-64 5051 5052 * Support for the [24]deprecated pcommit instruction has been 5053 removed. 5054 5055 GCC 6.4 5056 5057 This is the [25]list of problem reports (PRs) from GCC's bug tracking 5058 system that are known to be fixed in the 6.4 release. This list might 5059 not be complete (that is, it is possible that some PRs that have been 5060 fixed are not listed here). 5061 5062 Operating Systems 5063 5064 RTEMS 5065 5066 * The ABI changes on ARM so that no short enums are used by default. 5067 5068 GCC 6.5 5069 5070 This is the [26]list of problem reports (PRs) from GCC's bug tracking 5071 system that are known to be fixed in the 6.5 release. This list might 5072 not be complete (that is, it is possible that some PRs that have been 5073 fixed are not listed here). 5074 5075 5076 For questions related to the use of GCC, please consult these web 5077 pages and the [27]GCC manuals. If that fails, the 5078 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 5079 web pages and the development of GCC are welcome on our developer 5080 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 5081 archives. 5082 5083 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 5084 distribution of this entire article is permitted in any medium, 5085 provided this notice is preserved. 5086 5087 These pages are [32]maintained by the GCC team. Last modified 5088 2021-10-31[33]. 5089 5090 References 5091 5092 1. http://gcc.gnu.org/gcc-6/porting_to.html 5093 2. http://gcc.gnu.org/onlinedocs/index.html#current 5094 3. https://gcc.gnu.org/ml/gcc/2015-08/msg00101.html 5095 4. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71151 5096 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87822 5097 6. https://www.openacc.org/ 5098 7. https://gcc.gnu.org/wiki/OpenACC 5099 8. https://gcc.gnu.org/wiki/Offloading 5100 9. https://www.openmp.org/specifications/ 5101 10. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1266 5102 11. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4377.pdf 5103 12. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 5104 13. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/performance.html 5105 14. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/functions.html#gcc_jit_block_end_with_switch 5106 15. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_set_bool_allow_unreachable_blocks 5107 16. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_add_command_line_option 5108 17. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/AArch64-Function-Attributes.html#AArch64-Function-Attributes 5109 18. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/ARM-Function-Attributes.html#ARM-Function-Attributes 5110 19. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Named-Address-Spaces.html#Named-Address-Spaces 5111 20. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/S_002f390-Function-Attributes.html#S_002f390-Function-Attributes 5112 21. http://www.musl-libc.org/ 5113 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.2 5114 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.3 5115 24. https://www.intel.com/content/www/us/en/developer/articles/technical/deprecate-pcommit-instruction.html 5116 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.4 5117 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.5 5118 27. https://gcc.gnu.org/onlinedocs/ 5119 28. mailto:gcc-help (a] gcc.gnu.org 5120 29. mailto:gcc (a] gcc.gnu.org 5121 30. https://gcc.gnu.org/lists.html 5122 31. https://www.fsf.org/ 5123 32. https://gcc.gnu.org/about.html 5124 33. http://validator.w3.org/check/referer 5125 ====================================================================== 5126 http://gcc.gnu.org/gcc-5/index.html 5127 GCC 5 Release Series 5128 5129 (This release series is no longer supported.) 5130 5131 October 10, 2017 5132 5133 The [1]GNU project and the GCC developers are pleased to announce the 5134 release of GCC 5.5. 5135 5136 This release is a bug-fix release, containing fixes for regressions in 5137 GCC 5.4 relative to previous releases of GCC. 5138 5139 Release History 5140 5141 GCC 5.5 5142 October 10, 2017 ([2]changes, [3]documentation) 5143 5144 GCC 5.4 5145 June 3, 2016 ([4]changes, [5]documentation) 5146 5147 GCC 5.3 5148 December 4, 2015 ([6]changes, [7]documentation) 5149 5150 GCC 5.2 5151 July 16, 2015 ([8]changes, [9]documentation) 5152 5153 GCC 5.1 5154 April 22, 2015 ([10]changes, [11]documentation) 5155 5156 References and Acknowledgements 5157 5158 GCC used to stand for the GNU C Compiler, but since the compiler 5159 supports several other languages aside from C, it now stands for the 5160 GNU Compiler Collection. 5161 5162 A list of [12]successful builds is updated as new information becomes 5163 available. 5164 5165 The GCC developers would like to thank the numerous people that have 5166 contributed new features, improvements, bug fixes, and other changes as 5167 well as test results to GCC. This [13]amazing group of volunteers is 5168 what makes GCC successful. 5169 5170 For additional information about GCC please refer to the [14]GCC 5171 project web site or contact the [15]GCC development mailing list. 5172 5173 To obtain GCC please use [16]our mirror sites or [17]our version 5174 control system. 5175 5176 5177 For questions related to the use of GCC, please consult these web 5178 pages and the [18]GCC manuals. If that fails, the 5179 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 5180 web pages and the development of GCC are welcome on our developer 5181 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 5182 archives. 5183 5184 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 5185 distribution of this entire article is permitted in any medium, 5186 provided this notice is preserved. 5187 5188 These pages are [23]maintained by the GCC team. Last modified 5189 2021-07-28[24]. 5190 5191 References 5192 5193 1. http://www.gnu.org/ 5194 2. http://gcc.gnu.org/gcc-5/changes.html 5195 3. http://gcc.gnu.org/onlinedocs/5.5.0/ 5196 4. http://gcc.gnu.org/gcc-5/changes.html 5197 5. http://gcc.gnu.org/onlinedocs/5.4.0/ 5198 6. http://gcc.gnu.org/gcc-5/changes.html 5199 7. http://gcc.gnu.org/onlinedocs/5.3.0/ 5200 8. http://gcc.gnu.org/gcc-5/changes.html 5201 9. http://gcc.gnu.org/onlinedocs/5.2.0/ 5202 10. http://gcc.gnu.org/gcc-5/changes.html 5203 11. http://gcc.gnu.org/onlinedocs/5.1.0/ 5204 12. http://gcc.gnu.org/gcc-5/buildstat.html 5205 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 5206 14. http://gcc.gnu.org/index.html 5207 15. mailto:gcc (a] gcc.gnu.org 5208 16. http://gcc.gnu.org/mirrors.html 5209 17. http://gcc.gnu.org/git.html 5210 18. https://gcc.gnu.org/onlinedocs/ 5211 19. mailto:gcc-help (a] gcc.gnu.org 5212 20. mailto:gcc (a] gcc.gnu.org 5213 21. https://gcc.gnu.org/lists.html 5214 22. https://www.fsf.org/ 5215 23. https://gcc.gnu.org/about.html 5216 24. http://validator.w3.org/check/referer 5217 ====================================================================== 5218 http://gcc.gnu.org/gcc-5/changes.html 5219 GCC 5 Release Series 5220 Changes, New Features, and Fixes 5221 5222 Caveats 5223 5224 * The default mode for C is now -std=gnu11 instead of -std=gnu89. 5225 * The C++ runtime library (libstdc++) uses a new ABI by default (see 5226 [1]below). 5227 * The Graphite framework for loop optimizations no longer requires 5228 the CLooG library, only ISL version 0.14 (recommended) or 0.12.2. 5229 The installation manual contains more information about 5230 requirements to build GCC. 5231 * The non-standard C++0x type traits has_trivial_default_constructor, 5232 has_trivial_copy_constructor and has_trivial_copy_assign have been 5233 deprecated and will be removed in a future version. The standard 5234 C++11 traits is_trivially_default_constructible, 5235 is_trivially_copy_constructible and is_trivially_copy_assignable 5236 should be used instead. 5237 * On AVR, support has been added for the devices 5238 ATtiny4/5/9/10/20/40. This requires Binutils 2.25 or newer. 5239 * The AVR port uses a new scheme to describe supported devices: For 5240 each supported device the compiler provides a device-specific 5241 [2]spec file. If the compiler is used together with AVR-LibC, this 5242 requires at least GCC 5.2 and a version of AVR-LibC which 5243 implements [3]feature #44574. 5244 5245 General Optimizer Improvements 5246 5247 * Inter-procedural optimization improvements: 5248 + An Identical Code Folding (ICF) pass (controlled via 5249 -fipa-icf) has been added. Compared to the identical code 5250 folding performed by the Gold linker this pass does not 5251 require function sections. It also performs merging before 5252 inlining, so inter-procedural optimizations are aware of the 5253 code re-use. On the other hand not all unifications performed 5254 by a linker are doable by GCC which must honor aliasing 5255 information. During link-time optimization of Firefox, this 5256 pass unifies about 31000 functions, that is 14% overall. 5257 + The devirtualization pass was significantly improved by adding 5258 better support for speculative devirtualization and dynamic 5259 type detection. About 50% of virtual calls in Firefox are now 5260 speculatively devirtualized during link-time optimization. 5261 + A new comdat localization pass allows the linker to eliminate 5262 more dead code in presence of C++ inline functions. 5263 + Virtual tables are now optimized. Local aliases are used to 5264 reduce dynamic linking time of C++ virtual tables on ELF 5265 targets and data alignment has been reduced to limit data 5266 segment bloat. 5267 + A new -fno-semantic-interposition option can be used to 5268 improve code quality of shared libraries where interposition 5269 of exported symbols is not allowed. 5270 + Write-only variables are now detected and optimized out. 5271 + With profile feedback the function inliner can now bypass 5272 --param inline-insns-auto and --param inline-insns-single 5273 limits for hot calls. 5274 + The IPA reference pass was significantly sped up making it 5275 feasible to enable -fipa-reference with -fprofile-generate. 5276 This also solves a bottleneck seen when building Chromium with 5277 link-time optimization. 5278 + The symbol table and call-graph API was reworked to C++ and 5279 simplified. 5280 + The interprocedural propagation of constants now also 5281 propagates alignments of pointer parameters. This for example 5282 means that the vectorizer often does not need to generate loop 5283 prologues and epilogues to make up for potential 5284 misalignments. 5285 * Link-time optimization improvements: 5286 + One Definition Rule based merging of C++ types has been 5287 implemented. Type merging enables better devirtualization and 5288 alias analysis. Streaming extra information needed to merge 5289 types adds about 2-6% of memory size and object size increase. 5290 This can be controlled by -flto-odr-type-merging. 5291 + Command-line optimization and target options are now streamed 5292 on a per-function basis and honored by the link-time 5293 optimizer. This change makes link-time optimization a more 5294 transparent replacement of per-file optimizations. It is now 5295 possible to build projects that require different optimization 5296 settings for different translation units (such as -ffast-math, 5297 -mavx, or -finline). Contrary to earlier GCC releases, the 5298 optimization and target options passed on the link command 5299 line are ignored. 5300 Note that this applies only to those command-line options that 5301 can be passed to optimize and target attributes. Command-line 5302 options affecting global code generation (such as -fpic), 5303 warnings (such as -Wodr), optimizations affecting the way 5304 static variables are optimized (such as -fcommon), debug 5305 output (such as -g), and --param parameters can be applied 5306 only to the whole link-time optimization unit. In these cases, 5307 it is recommended to consistently use the same options at both 5308 compile time and link time. 5309 + GCC bootstrap now uses slim LTO object files. 5310 + Memory usage and link times were improved. Tree merging was 5311 sped up, memory usage of GIMPLE declarations and types was 5312 reduced, and, support for on-demand streaming of variable 5313 constructors was added. 5314 * Feedback directed optimization improvements: 5315 + A new auto-FDO mode uses profiles collected by low overhead 5316 profiling tools (perf) instead of more expensive program 5317 instrumentation (via -fprofile-generate). SPEC2006 benchmarks 5318 on x86-64 improve by 4.7% with auto-FDO and by 7.3% with 5319 traditional feedback directed optimization. 5320 + Profile precision was improved in presence of C++ inline and 5321 extern inline functions. 5322 + The new gcov-tool utility allows manipulating profiles. 5323 + Profiles are now more tolerant to source file changes (this 5324 can be controlled by --param profile-func-internal-id). 5325 * Register allocation improvements: 5326 + A new local register allocator (LRA) sub-pass, controlled by 5327 -flra-remat, implements control-flow sensitive global register 5328 rematerialization. Instead of spilling and restoring a 5329 register value, it is recalculated if it is profitable. The 5330 sub-pass improved SPEC2000 generated code by 1% and 0.5% 5331 correspondingly on ARM and x86-64. 5332 + Reuse of the PIC hard register, instead of using a fixed 5333 register, was implemented on x86/x86-64 targets. This improves 5334 generated PIC code performance as more hard registers can be 5335 used. Shared libraries can significantly benefit from this 5336 optimization. Currently it is switched on only for x86/x86-64 5337 targets. As RA infrastructure is already implemented for PIC 5338 register reuse, other targets might follow this in the future. 5339 + A simple form of inter-procedural RA was implemented. When it 5340 is known that a called function does not use caller-saved 5341 registers, save/restore code is not generated around the call 5342 for such registers. This optimization can be controlled by 5343 -fipa-ra 5344 + LRA is now much more effective at generating spills of general 5345 registers into vector registers instead of memory on 5346 architectures (e.g., modern Intel processors) where this is 5347 profitable. 5348 * UndefinedBehaviorSanitizer gained a few new sanitization options: 5349 + -fsanitize=float-divide-by-zero: detect floating-point 5350 division by zero; 5351 + -fsanitize=float-cast-overflow: check that the result of 5352 floating-point type to integer conversions do not overflow; 5353 + -fsanitize=bounds: enable instrumentation of array bounds and 5354 detect out-of-bounds accesses; 5355 + -fsanitize=alignment: enable alignment checking, detect 5356 various misaligned objects; 5357 + -fsanitize=object-size: enable object size checking, detect 5358 various out-of-bounds accesses. 5359 + -fsanitize=vptr: enable checking of C++ member function calls, 5360 member accesses and some conversions between pointers to base 5361 and derived classes, detect if the referenced object does not 5362 have the correct dynamic type. 5363 * Pointer Bounds Checker, a bounds violation detector, has been added 5364 and can be enabled via -fcheck-pointer-bounds. Memory accesses are 5365 instrumented with run-time checks of used pointers against their 5366 bounds to detect pointer bounds violations (overflows). The Pointer 5367 Bounds Checker is available on x86/x86-64 GNU/Linux targets with a 5368 new ISA extension Intel MPX support. See the Pointer Bounds Checker 5369 [4]Wiki page for more details. 5370 5371 New Languages and Language specific improvements 5372 5373 * [5]OpenMP 4.0 specification offloading features are now supported 5374 by the C, C++, and Fortran compilers. Generic changes: 5375 + Infrastructure (suitable for any vendor). 5376 + Testsuite which covers offloading from the [6]OpenMP 4.0 5377 Examples document. 5378 Specific for upcoming Intel Xeon Phi products: 5379 + Run-time library. 5380 + Card emulator. 5381 * GCC 5 includes a preliminary implementation of the OpenACC 2.0a 5382 specification. OpenACC is intended for programming accelerator 5383 devices such as GPUs. See [7]the OpenACC wiki page for more 5384 information. 5385 5386 C family 5387 5388 * The default setting of the -fdiagnostics-color= command-line option 5389 is now [8]configurable when building GCC using configuration option 5390 --with-diagnostics-color=. The possible values are: never, always, 5391 auto and auto-if-env. The new default auto uses color only when the 5392 standard error is a terminal. The default in GCC 4.9 was 5393 auto-if-env, which is equivalent to auto if there is a non-empty 5394 GCC_COLORS environment variable, and never otherwise. As in GCC 5395 4.9, an empty GCC_COLORS variable in the environment will always 5396 disable colors, no matter what the default is or what command-line 5397 options are used. 5398 * A new command-line option -Wswitch-bool has been added for the C 5399 and C++ compilers, which warns whenever a switch statement has an 5400 index of boolean type. 5401 * A new command-line option -Wlogical-not-parentheses has been added 5402 for the C and C++ compilers, which warns about "logical not" used 5403 on the left hand side operand of a comparison. 5404 * A new command-line option -Wsizeof-array-argument has been added 5405 for the C and C++ compilers, which warns when the sizeof operator 5406 is applied to a parameter that has been declared as an array in a 5407 function definition. 5408 * A new command-line option -Wbool-compare has been added for the C 5409 and C++ compilers, which warns about boolean expressions compared 5410 with an integer value different from true/false. 5411 * Full support for Cilk Plus has been added to the GCC compiler. Cilk 5412 Plus is an extension to the C and C++ languages to support data and 5413 task parallelism. 5414 * A new attribute no_reorder prevents reordering of selected symbols 5415 against other such symbols or inline assembler. This enables to 5416 link-time optimize the Linux kernel without having to resort to 5417 -fno-toplevel-reorder that disables several optimizations. 5418 * New preprocessor constructs, __has_include and __has_include_next, 5419 to test the availability of headers have been added. 5420 This demonstrates a way to include the header <optional> only if it 5421 is available: 5422 5423 #ifdef __has_include 5424 # if __has_include(<optional>) 5425 # include <optional> 5426 # define have_optional 1 5427 # elif __has_include(<experimental/optional>) 5428 # include <experimental/optional> 5429 # define have_optional 1 5430 # define experimental_optional 5431 # else 5432 # define have_optional 0 5433 # endif 5434 #endif 5435 5436 The header search paths for __has_include and __has_include_next 5437 are equivalent to those of the standard directive #include and the 5438 extension #include_next respectively. 5439 * A new built-in function-like macro to determine the existence of an 5440 attribute, __has_attribute, has been added. The equivalent built-in 5441 macro __has_cpp_attribute was added to C++ to support 5442 [9]Feature-testing recommendations for C++. The macro 5443 __has_attribute is added to all C-like languages as an extension: 5444 5445 int 5446 #ifdef __has_attribute 5447 # if __has_attribute(__noinline__) 5448 __attribute__((__noinline__)) 5449 # endif 5450 #endif 5451 foo(int x); 5452 5453 If an attribute exists, a nonzero constant integer is returned. For 5454 standardized C++ attributes a date is returned, otherwise the 5455 constant returned is 1. Both __has_attribute and 5456 __has_cpp_attribute will add underscores to an attribute name if 5457 necessary to resolve the name. For C++11 and onwards the attribute 5458 may be scoped. 5459 * A new set of built-in functions for arithmetics with overflow 5460 checking has been added: __builtin_add_overflow, 5461 __builtin_sub_overflow and __builtin_mul_overflow and for 5462 compatibility with clang also other variants. These builtins have 5463 two integral arguments (which don't need to have the same type), 5464 the arguments are extended to infinite precision signed type, +, - 5465 or * is performed on those, and the result is stored in an integer 5466 variable pointed to by the last argument. If the stored value is 5467 equal to the infinite precision result, the built-in functions 5468 return false, otherwise true. The type of the integer variable that 5469 will hold the result can be different from the types of the first 5470 two arguments. The following snippet demonstrates how this can be 5471 used in computing the size for the calloc function: 5472 5473 void * 5474 calloc (size_t x, size_t y) 5475 { 5476 size_t sz; 5477 if (__builtin_mul_overflow (x, y, &sz)) 5478 return NULL; 5479 void *ret = malloc (sz); 5480 if (ret) memset (res, 0, sz); 5481 return ret; 5482 } 5483 5484 On e.g. i?86 or x86-64 the above will result in a mul instruction 5485 followed by a jump on overflow. 5486 * The option -fextended-identifiers is now enabled by default for 5487 C++, and for C99 and later C versions. Various bugs in the 5488 implementation of extended identifiers have been fixed. 5489 5490 C 5491 5492 * The default mode has been changed to -std=gnu11. 5493 * A new command-line option -Wc90-c99-compat has been added to warn 5494 about features not present in ISO C90, but present in ISO C99. 5495 * A new command-line option -Wc99-c11-compat has been added to warn 5496 about features not present in ISO C99, but present in ISO C11. 5497 * It is possible to disable warnings about conversions between 5498 pointers that have incompatible types via a new warning option 5499 -Wno-incompatible-pointer-types; warnings about implicit 5500 incompatible integer to pointer and pointer to integer conversions 5501 via a new warning option -Wno-int-conversion; and warnings about 5502 qualifiers on pointers being discarded via a new warning option 5503 -Wno-discarded-qualifiers. 5504 * To allow proper use of const qualifiers with multidimensional 5505 arrays, GCC will not warn about incompatible pointer types anymore 5506 for conversions between pointers to arrays with and without const 5507 qualifier (except when using -pedantic). Instead, a new warning is 5508 emitted only if the const qualifier is lost. This can be controlled 5509 with a new warning option -Wno-discarded-array-qualifiers. 5510 * The C front end now generates more precise caret diagnostics. 5511 * The -pg command-line option now only affects the current file in an 5512 LTO build. 5513 5514 C++ 5515 5516 * G++ now supports [10]C++14 variable templates. 5517 * -Wnon-virtual-dtor doesn't warn anymore for final classes. 5518 * Excessive template instantiation depth is now a fatal error. This 5519 prevents excessive diagnostics that usually do not help to identify 5520 the problem. 5521 * G++ and libstdc++ now implement the feature-testing macros from 5522 [11]Feature-testing recommendations for C++. 5523 * G++ now allows typename in a template template parameter. 5524 5525 template<template<typename> typename X> struct D; // OK 5526 5527 * G++ now supports [12]C++14 aggregates with non-static data member 5528 initializers. 5529 5530 struct A { int i, j = i; }; 5531 A a = { 42 }; // a.j is also 42 5532 5533 * G++ now supports [13]C++14 extended constexpr. 5534 5535 constexpr int f (int i) 5536 { 5537 int j = 0; 5538 for (; i > 0; --i) 5539 ++j; 5540 return j; 5541 } 5542 5543 constexpr int i = f(42); // i is 42 5544 5545 * G++ now supports the [14]C++14 sized deallocation functions. 5546 5547 void operator delete (void *, std::size_t) noexcept; 5548 void operator delete[] (void *, std::size_t) noexcept; 5549 5550 * A new One Definition Rule violation warning (controlled by -Wodr) 5551 detects mismatches in type definitions and virtual table contents 5552 during link-time optimization. 5553 * New warnings -Wsuggest-final-types and -Wsuggest-final-methods help 5554 developers to annotate programs with final specifiers (or anonymous 5555 namespaces) to improve code generation. These warnings can be used 5556 at compile time, but they are more useful in combination with 5557 link-time optimization. 5558 * G++ no longer supports [15]N3639 variable length arrays, as they 5559 were removed from the C++14 working paper prior to ratification. 5560 GNU VLAs are still supported, so VLA support is now the same in 5561 C++14 mode as in C++98 and C++11 modes. 5562 * G++ now allows passing a non-trivially-copyable class via C 5563 varargs, which is conditionally-supported with 5564 implementation-defined semantics in the standard. This uses the 5565 same calling convention as a normal value parameter. 5566 * G++ now defaults to -fabi-version=9 and -fabi-compat-version=2. So 5567 various mangling bugs are fixed, but G++ will still emit aliases 5568 with the old, wrong mangling where feasible. -Wabi=2 will warn 5569 about differences between ABI version 2 and the current setting. 5570 * G++ 5.2 fixes the alignment of std::nullptr_t. Most code is likely 5571 to be unaffected, but -Wabi=8 will warn about a non-static data 5572 member with type std::nullptr_t which changes position due to this 5573 change. 5574 5575 Runtime Library (libstdc++) 5576 5577 * A [16]Dual ABI is provided by the library. A new ABI is enabled by 5578 default. The old ABI is still supported and can be used by defining 5579 the macro _GLIBCXX_USE_CXX11_ABI to 0 before including any C++ 5580 standard library headers. 5581 * A new implementation of std::string is enabled by default, using 5582 the small string optimization instead of copy-on-write reference 5583 counting. 5584 * A new implementation of std::list is enabled by default, with an 5585 O(1) size() function; 5586 * [17]Full support for C++11, including the following new features: 5587 + std::deque and std::vector<bool> meet the allocator-aware 5588 container requirements; 5589 + movable and swappable iostream classes; 5590 + support for std::align and std::aligned_union; 5591 + type traits std::is_trivially_copyable, 5592 std::is_trivially_constructible, std::is_trivially_assignable 5593 etc.; 5594 + I/O manipulators std::put_time, std::get_time, std::hexfloat 5595 and std::defaultfloat; 5596 + generic locale-aware std::isblank; 5597 + locale facets for Unicode conversion; 5598 + atomic operations for std::shared_ptr; 5599 + std::notify_all_at_thread_exit() and functions for making 5600 futures ready at thread exit. 5601 * Support for the C++11 hexfloat manipulator changes how the num_put 5602 facet formats floating point types when 5603 ios_base::fixed|ios_base::scientific is set in a stream's fmtflags. 5604 This change affects all language modes, even though the C++98 5605 standard gave no special meaning to that combination of flags. To 5606 prevent the use of hexadecimal notation for floating point types 5607 use str.unsetf(std::ios_base::floatfield) to clear the relevant 5608 bits in str.flags(). 5609 * [18]Full experimental support for C++14, including the following 5610 new features: 5611 + std::is_final type trait; 5612 + heterogeneous comparison lookup in associative containers. 5613 + global functions cbegin, cend, rbegin, rend, crbegin, and 5614 crend for range access to containers, arrays and initializer 5615 lists. 5616 * [19]Improved experimental support for the Library Fundamentals TS, 5617 including: 5618 + class std::experimental::any; 5619 + function template std::experimental::apply; 5620 + function template std::experimental::sample; 5621 + function template std::experimental::search and related 5622 searcher types; 5623 + variable templates for type traits; 5624 + function template std::experimental::not_fn. 5625 * New random number distributions logistic_distribution and 5626 uniform_on_sphere_distribution as extensions. 5627 * [20]GDB Xmethods for containers and std::unique_ptr. 5628 5629 Fortran 5630 5631 * Compatibility notice: 5632 + The version of the module files (.mod) has been incremented. 5633 + For free-form source files [21]-Werror=line-truncation is now 5634 enabled by default. Note that comments exceeding the line 5635 length are not diagnosed. (For fixed-form source code, the 5636 same warning is available but turned off by default, such that 5637 excess characters are ignored. -ffree-line-length-n and 5638 -ffixed-line-length-n can be used to modify the default line 5639 lengths of 132 and 72 columns, respectively.) 5640 + The -Wtabs option is now more sensible: with -Wtabs the 5641 compiler warns if it encounters tabs and with -Wno-tabs this 5642 warning is turned off. Before, -Wno-tabs warned and -Wtabs 5643 disabled the warning. As before, this warning is also enabled 5644 by -Wall, -pedantic and the f95, f2003, f2008 and f2008ts 5645 options of -std=. 5646 * Incomplete support for colorizing diagnostics emitted by gfortran 5647 has been added. The option [22]-fdiagnostics-color controls when 5648 color is used in diagnostics. The default value of this option can 5649 be [23]configured when building GCC. The GCC_COLORS environment 5650 variable can be used to customize the colors or disable coloring 5651 completely. Sample diagnostics output: 5652 $ gfortran -fdiagnostics-color=always -Wuse-without-only test.f90 5653 test.f90:6:1: 5654 5655 0 continue 5656 1 5657 Error: Zero is not a valid statement label at (1) 5658 test.f90:9:6: 5659 5660 USE foo 5661 1 5662 Warning: USE statement at (1) has no ONLY qualifier [-Wuse-without-only] 5663 5664 * The -Wuse-without-only option has been added to warn when a USE 5665 statement has no ONLY qualifier and thus implicitly imports all 5666 public entities of the used module. 5667 * Formatted READ and WRITE statements now work correctly in 5668 locale-aware programs. For more information and potential caveats, 5669 see [24]Section 5.3 Thread-safety of the runtime library in the 5670 manual. 5671 * [25]Fortran 2003: 5672 + The intrinsic IEEE modules (IEEE_FEATURES, IEEE_EXCEPTIONS and 5673 IEEE_ARITHMETIC) are now supported. 5674 * [26]Fortran 2008: 5675 + [27]Coarrays: Full experimental support of Fortran 2008's 5676 coarrays with -fcoarray=lib except for allocatable/pointer 5677 components of derived-type coarrays. GCC currently only ships 5678 with a single-image library (libcaf_single), but multi-image 5679 support based on MPI and GASNet is provided by the libraries 5680 of the [28]OpenCoarrays project. 5681 * TS18508 Additional Parallel Features in Fortran: 5682 + Support for the collective intrinsic subroutines CO_MAX, 5683 CO_MIN, CO_SUM, CO_BROADCAST and CO_REDUCE has been added, 5684 including -fcoarray=lib support. 5685 + Support for the new atomic intrinsics has been added, 5686 including -fcoarray=lib support. 5687 * Fortran 2015: 5688 + Support for IMPLICIT NONE (external, type). 5689 + ERROR STOP is now permitted in pure procedures. 5690 5691 Go 5692 5693 * GCC 5 provides a complete implementation of the Go 1.4.2 release. 5694 * Building GCC 5 with Go enabled will install two new programs: 5695 [29]go and [30]gofmt. 5696 5697 libgccjit 5698 5699 New in GCC 5 is the ability to build GCC as a shared library for 5700 embedding in other processes (such as interpreters), suitable for 5701 Just-In-Time compilation to machine code. 5702 5703 The shared library has a [31]C API and a [32]C++ wrapper API providing 5704 some "syntactic sugar". There are also bindings available from 3rd 5705 parties for [33]Python and for [34]D. 5706 5707 For example, this library can be used by interpreters for [35]compiling 5708 functions from bytecode to machine code. 5709 5710 The library can also be used for ahead-of-time compilation, enabling 5711 GCC to be plugged into a pre-existing front end. An example of using 5712 this to build a compiler for an esoteric language we'll refer to as 5713 "brainf" can be seen [36]here. 5714 5715 libgccjit is licensed under the GPLv3 (or at your option, any later 5716 version) 5717 5718 It should be regarded as experimental at this time. 5719 5720 New Targets and Target Specific Improvements 5721 5722 Reporting stack usage 5723 5724 * The BFIN, FT32, H8300, IQ2000 and M32C targets now support the 5725 -fstack-usage option. 5726 5727 AArch64 5728 5729 * Code generation for the ARM Cortex-A57 processor has been improved. 5730 A more accurate instruction scheduling model for the processor is 5731 now used, and a number of compiler tuning parameters have been set 5732 to offer increased performance when compiling with -mcpu=cortex-a57 5733 or -mtune=cortex-a57. 5734 * A workaround for the ARM Cortex-A53 erratum 835769 has been added 5735 and can be enabled by giving the -mfix-cortex-a53-835769 option. 5736 Alternatively it can be enabled by default by configuring GCC with 5737 the --enable-fix-cortex-a53-835769 option. 5738 * The optional cryptographic extensions to the ARMv8-A architecture 5739 are no longer enabled by default when specifying the 5740 -mcpu=cortex-a53, -mcpu=cortex-a57 or -mcpu=cortex-a57.cortex-a53 5741 options. To enable these extensions add +crypto to the value of 5742 -mcpu or -march e.g. -mcpu=cortex-a53+crypto. 5743 * Support has been added for the following processors (GCC 5744 identifiers in parentheses): ARM Cortex-A72 (cortex-a72) and 5745 initial support for its big.LITTLE combination with the ARM 5746 Cortex-A53 (cortex-a72.cortex-a53), Cavium ThunderX (thunderx), 5747 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 5748 The GCC identifiers can be used as arguments to the -mcpu or -mtune 5749 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 5750 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 5751 support for the Cortex-A72. 5752 * The transitional options -mlra and -mno-lra have been removed. The 5753 AArch64 backend now uses the local register allocator (LRA) only. 5754 5755 ARM 5756 5757 * Thumb-1 assembly code is now generated in unified syntax. The new 5758 option -masm-syntax-unified specifies whether inline assembly code 5759 is using unified syntax. By default the option is off which means 5760 non-unified syntax is used. However this is subject to change in 5761 future releases. Eventually the non-unified syntax will be 5762 deprecated. 5763 * It is now a configure-time error to use the --with-cpu configure 5764 option with either of --with-tune or --with-arch. 5765 * Code generation for the ARM Cortex-A57 processor has been improved. 5766 A more accurate instruction scheduling model for the processor is 5767 now used, and a number of compiler tuning parameters have been set 5768 to offer increased performance when compiling with -mcpu=cortex-a57 5769 or -mtune=cortex-a57. 5770 * Support has been added for the following processors (GCC 5771 identifiers in parentheses): ARM Cortex-A17 (cortex-a17) and 5772 initial support for its big.LITTLE combination with the ARM 5773 Cortex-A7 (cortex-a17.cortex-a7), ARM Cortex-A72 (cortex-a72) and 5774 initial support for its big.LITTLE combination with the ARM 5775 Cortex-A53 (cortex-a72.cortex-a53), ARM Cortex-M7 (cortex-m7), 5776 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 5777 The GCC identifiers can be used as arguments to the -mcpu or -mtune 5778 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 5779 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 5780 support for the Cortex-A72. 5781 * The deprecated option -mwords-little-endian has been removed. 5782 * The options -mapcs, -mapcs-frame, -mtpcs-frame and 5783 -mtpcs-leaf-frame which are only applicable to the old ABI have 5784 been deprecated. 5785 * The transitional options -mlra and -mno-lra have been removed. The 5786 ARM backend now uses the local register allocator (LRA) only. 5787 5788 AVR 5789 5790 * The compiler no more supports individual devices like ATmega8. 5791 Specifying, say, -mmcu=atmega8 triggers the usage of the 5792 device-specific [37]spec file specs-atmega8 which is part of the 5793 installation and describes options for the sub-processes like 5794 compiler proper, assembler and linker. You can add support for a 5795 new device -mmcu=mydevice as follows: 5796 1. In an empty directory /someplace, create a new directory 5797 device-specs. 5798 2. Copy a device spec file from the installed device-specs 5799 folder, follow the comments in that file and then save it as 5800 /someplace/device-specs/specs-mydevice. 5801 3. Add -B /someplace -mmcu=mydevice to the compiler's 5802 command-line options. Notice that /someplace must specify an 5803 absolute path and that mydevice must not start with "avr". 5804 4. Provided you have a device-specific library libmydevice.a 5805 available, you can put it at /someplace, dito for a 5806 device-specific startup file crtmydevice.o. 5807 The contents of the device spec files depend on the compiler's 5808 configuration, in particular on --with-avrlibc=no and whether or 5809 not it is configured for RTEMS. 5810 * A new command-line option -nodevicelib has been added. It prevents 5811 the compiler from linking against AVR-LibC's device-specific 5812 library libdevice.a. 5813 * The following three command-line options have been added: 5814 5815 -mrmw 5816 Set if the device supports the read-modify-write 5817 instructions LAC, LAS, LAT and XCH. 5818 5819 -mn-flash=size 5820 Specify the flash size of the device in units of 64 KiB, 5821 rounded up to the next integer as needed. This option 5822 affects the availability of the [38]AVR address-spaces. 5823 5824 -mskip-bug 5825 Set if the device is affected by the respective silicon 5826 bug. 5827 5828 In general, you don't need to set these options by hand. The new 5829 device-specific spec file will set them as needed. 5830 5831 IA-32/x86-64 5832 5833 * New ISA extensions support AVX-512{BW,DQ,VL,IFMA,VBMI} of Intel's 5834 CPU codenamed Skylake Server was added to GCC. That includes inline 5835 assembly support, new intrinsics, and basic autovectorization. 5836 These new AVX-512 extensions are available via the following GCC 5837 switches: AVX-512 Vector Length EVEX feature: -mavx512vl, AVX-512 5838 Byte and Word instructions: -mavx512bw, AVX-512 Dword and Qword 5839 instructions: -mavx512dq, AVX-512 FMA-52 instructions: -mavx512ifma 5840 and for AVX-512 Vector Bit Manipulation Instructions: -mavx512vbmi. 5841 * New ISA extensions support Intel MPX was added to GCC. This new 5842 extension is available via the -mmpx compiler switch. Intel MPX is 5843 a set of processor features which, with compiler, run-time library 5844 and OS support, brings increased robustness to software by run-time 5845 checking pointer references against their bounds. In GCC Intel MPX 5846 is supported by Pointer Bounds Checker and libmpx run-time 5847 libraries. 5848 * The new -mrecord-mcount option for -pg generates a Linux kernel 5849 style table of pointers to mcount or __fentry__ calls at the 5850 beginning of functions. The new -mnop-mcount option in addition 5851 also generates nops in place of the __fentry__ or mcount call, so 5852 that a call per function can be later patched in. This can be used 5853 for low overhead tracing or hot code patching. 5854 * The new -malign-data option controls how GCC aligns variables. 5855 -malign-data=compat uses increased alignment compatible with GCC 5856 4.8 and earlier, -malign-data=abi uses alignment as specified by 5857 the psABI, and -malign-data=cacheline uses increased alignment to 5858 match the cache line size. -malign-data=compat is the default. 5859 * The new -mskip-rax-setup option skips setting up the RAX register 5860 when SSE is disabled and there are no variable arguments passed in 5861 vector registers. This can be used to optimize the Linux kernel. 5862 5863 MIPS 5864 5865 * MIPS Releases 3 and 5 are now directly supported. Use the 5866 command-line options -mips32r3, -mips64r3, -mips32r5 and -mips64r5 5867 to enable code-generation for these processors. 5868 * The Imagination P5600 processor is now supported using the 5869 -march=p5600 command-line option. 5870 * The Cavium Octeon3 processor is now supported using the 5871 -march=octeon3 command-line option. 5872 * MIPS Release 6 is now supported using the -mips32r6 and -mips64r6 5873 command-line options. 5874 * The o32 ABI has been modified and extended. The o32 64-bit 5875 floating-point register support is now obsolete and has been 5876 removed. It has been replaced by three ABI extensions FPXX, FP64A, 5877 and FP64. The meaning of the -mfp64 command-line option has 5878 changed. It is now used to enable the FP64A and FP64 ABI 5879 extensions. 5880 + The FPXX extension requires that code generated to access 5881 double-precision values use even-numbered registers. Code that 5882 adheres to this extension is link-compatible with all other 5883 o32 double-precision ABI variants and will execute correctly 5884 in all hardware FPU modes. The command-line options -mabi=32 5885 -mfpxx can be used to enable this extension. MIPS II is the 5886 minimum processor required. 5887 + The o32 FP64A extension requires that floating-point registers 5888 be 64-bit and odd-numbered single-precision registers are not 5889 allowed. Code that adheres to the o32 FP64A variant is 5890 link-compatible with all other o32 double-precision ABI 5891 variants. The command-line options -mabi=32 -mfp64 5892 -mno-odd-spreg can be used to enable this extension. MIPS32R2 5893 is the minimum processor required. 5894 + The o32 FP64 extension also requires that floating-point 5895 registers be 64-bit, but permits the use of single-precision 5896 registers. Code that adheres to the o32 FP64 variant is 5897 link-compatible with o32 FPXX and o32 FP64A variants only, 5898 i.e. it is not compatible with the original o32 5899 double-precision ABI. The command-line options -mabi=32 -mfp64 5900 -modd-spreg can be used to enable this extension. MIPS32R2 is 5901 the minimum processor required. 5902 The new ABI variants can be enabled by default using the configure 5903 time options --with-fp-32=[32|xx|64] and --with(out)-odd-sp-reg-32. 5904 It is strongly recommended that all vendors begin to set o32 FPXX 5905 as the default ABI. This will be required to run the generated code 5906 on MIPSR5 cores in conjunction with future MIPS SIMD (MSA) code and 5907 MIPSR6 cores. 5908 * GCC will now pass all floating-point options to the assembler if 5909 GNU binutils 2.25 is used. As a result, any inline assembly code 5910 that uses hard-float instructions should be amended to include a 5911 .set directive to override the global assembler options when 5912 compiling for soft-float targets. 5913 5914 NDS32 5915 5916 * The variadic function ABI implementation is now compatible with 5917 past Andes toolchains where the caller uses registers to pass 5918 arguments and the callee is in charge of pushing them on stack. 5919 * The options -mforce-fp-as-gp, -mforbid-fp-as-gp, and -mex9 have 5920 been removed since they are not yet available in the nds32 port of 5921 GNU binutils. 5922 * A new option -mcmodel=[small|medium|large] supports varied code 5923 models on code generation. The -mgp-direct option became 5924 meaningless and can be discarded. 5925 5926 RX 5927 5928 * A new command line option -mno-allow-string-insns can be used to 5929 disable the generation of the SCMPU, SMOVU, SMOVB, SMOVF, SUNTIL, 5930 SWHILE and RMPA instructions. An erratum released by Renesas shows 5931 that it is unsafe to use these instructions on addresses within the 5932 I/O space of the processor. The new option can be used when the 5933 programmer is concerned that the I/O space might be accessed. The 5934 default is still to enable these instructions. 5935 5936 SH 5937 5938 * The compiler will now pass the appropriate --isa= option to the 5939 assembler. 5940 * The default handling for the GBR has been changed from call 5941 clobbered to call preserved. The old behavior can be reinstated by 5942 specifying the option -fcall-used-gbr. 5943 * Support for the SH4A fpchg instruction has been added which will be 5944 utilized when switching between single and double precision FPU 5945 modes. 5946 * The compiler no longer uses the __fpscr_values array for switching 5947 between single and double FPU precision modes on non-SH4A targets. 5948 Instead mode switching will now be performed by storing, modifying 5949 and reloading the FPSCR, so that other FPSCR bits are preserved 5950 across mode switches. The __fpscr_values array that is defined in 5951 libgcc is still present for backwards compatibility, but it will 5952 not be referenced by compiler generated code anymore. 5953 * New builtin functions __builtin_sh_get_fpscr and 5954 __builtin_sh_set_fpscr have been added. The __builtin_sh_set_fpscr 5955 function will mask the specified bits in such a way that the SZ, PR 5956 and FR mode bits will be preserved, while changing the other bits. 5957 These new functions do not reference the __fpscr_values array. The 5958 old functions __set_fpscr and __get_fpscr in libgcc which access 5959 the __fpscr_values array are still present for backwards 5960 compatibility, but their usage is highly discouraged. 5961 * Some improvements to code generated for __atomic built-in 5962 functions. 5963 * When compiling for SH2E the compiler will no longer force the usage 5964 of delay slots for conditional branch instructions bt and bf. The 5965 old behavior can be reinstated (e.g. to work around a hardware bug 5966 in the original SH7055) by specifying the new option 5967 -mcbranch-force-delay-slot. 5968 5969 Operating Systems 5970 5971 AIX 5972 5973 * GCC now supports stabs debugging continuation lines to allow long 5974 stabs debug information without overflow that generates AIX linker 5975 errors. 5976 5977 DragonFly BSD 5978 5979 * GCC now supports the DragonFly BSD operating system. 5980 5981 FreeBSD 5982 5983 * GCC now supports the FreeBSD operating system for the arm port 5984 through the arm*-*-freebsd* target triplets. 5985 5986 VxWorks MILS 5987 5988 * GCC now supports the MILS (Multiple Independent Levels of Security) 5989 variant of WindRiver's VxWorks operating system for PowerPC 5990 targets. 5991 5992 Other significant improvements 5993 5994 * The gcc-ar, gcc-nm, gcc-ranlib wrappers now understand a -B option 5995 to set the compiler to use. 5996 5997 * When the new command-line option -freport-bug is used, GCC 5998 automatically generates a developer-friendly reproducer whenever an 5999 internal compiler error is encountered. 6000 6001 GCC 5.2 6002 6003 This is the [39]list of problem reports (PRs) from GCC's bug tracking 6004 system that are known to be fixed in the 5.2 release. This list might 6005 not be complete (that is, it is possible that some PRs that have been 6006 fixed are not listed here). 6007 6008 Target Specific Changes 6009 6010 IA-32/x86-64 6011 6012 * Support for new AMD instructions monitorx and mwaitx has been 6013 added. This includes new intrinsic and built-in support. It is 6014 enabled through option -mmwaitx. The instructions monitorx and 6015 mwaitx implement the same functionality as the old monitor and 6016 mwait instructions. In addition mwaitx adds a configurable timer. 6017 The timer value is received as third argument and stored in 6018 register %ebx. 6019 6020 S/390, System z, IBM z Systems 6021 6022 * Support for the IBM z13 processor has been added. When using the 6023 -march=z13 option, the compiler will generate code making use of 6024 the new instructions and registers introduced with the vector 6025 extension facility. The -mtune=z13 option enables z13 specific 6026 instruction scheduling without making use of new instructions. 6027 Compiling code with -march=z13 reduces the default alignment of 6028 vector types bigger than 8 bytes to 8. This is an ABI change and 6029 care must be taken when linking modules compiled with different 6030 arch levels which interchange variables containing vector type 6031 values. For newly compiled code the GNU linker will emit a warning. 6032 * The -mzvector option enables a C/C++ language extension. This 6033 extension provides a new keyword vector which can be used to define 6034 vector type variables. (Note: This is not available when enforcing 6035 strict standard compliance e.g. with -std=c99. Either enable GNU 6036 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 6037 Additionally a set of overloaded builtins is provided which is 6038 partially compatible to the PowerPC Altivec builtins. In order to 6039 make use of these builtins the vecintrin.h header file needs to be 6040 included. 6041 6042 GCC 5.3 6043 6044 This is the [40]list of problem reports (PRs) from GCC's bug tracking 6045 system that are known to be fixed in the 5.3 release. This list might 6046 not be complete (that is, it is possible that some PRs that have been 6047 fixed are not listed here). 6048 6049 Target Specific Changes 6050 6051 IA-32/x86-64 6052 6053 * GCC now supports the Intel CPU named Skylake with AVX-512 6054 extensions through -march=skylake-avx512. The switch enables the 6055 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 6056 AVX-512DQ. 6057 6058 S/390, System z, IBM z Systems 6059 6060 * With this version of GCC IBM z Systems support has been added to 6061 the GO runtime environment. GCC 5.3 has proven to be able to 6062 compile larger GO applications on IBM z Systems. 6063 6064 GCC 5.4 6065 6066 This is the [41]list of problem reports (PRs) from GCC's bug tracking 6067 system that are known to be fixed in the 5.4 release. This list might 6068 not be complete (that is, it is possible that some PRs that have been 6069 fixed are not listed here). 6070 6071 GCC 5.5 6072 6073 This is the [42]list of problem reports (PRs) from GCC's bug tracking 6074 system that are known to be fixed in the 5.5 release. This list might 6075 not be complete (that is, it is possible that some PRs that have been 6076 fixed are not listed here). 6077 6078 Target Specific Changes 6079 6080 IA-32/x86-64 6081 6082 * Support for the [43]deprecated pcommit instruction has been 6083 removed. 6084 6085 6086 For questions related to the use of GCC, please consult these web 6087 pages and the [44]GCC manuals. If that fails, the 6088 [45]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6089 web pages and the development of GCC are welcome on our developer 6090 list at [46]gcc (a] gcc.gnu.org. All of [47]our lists have public 6091 archives. 6092 6093 Copyright (C) [48]Free Software Foundation, Inc. Verbatim copying and 6094 distribution of this entire article is permitted in any medium, 6095 provided this notice is preserved. 6096 6097 These pages are [49]maintained by the GCC team. Last modified 6098 2022-03-11[50]. 6099 6100 References 6101 6102 1. http://gcc.gnu.org/gcc-5/changes.html#libstdcxx 6103 2. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 6104 3. https://savannah.nongnu.org/bugs/?44574 6105 4. https://gcc.gnu.org/wiki/Intel MPX support in the GCC compiler 6106 5. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.pdf 6107 6. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.Examples.pdf 6108 7. https://gcc.gnu.org/wiki/OpenACC 6109 8. https://gcc.gnu.org/install/configure.html 6110 9. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 6111 10. http://gcc.gnu.org/projects/cxx1y.html 6112 11. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 6113 12. http://gcc.gnu.org/projects/cxx1y.html 6114 13. http://gcc.gnu.org/projects/cxx1y.html 6115 14. http://gcc.gnu.org/projects/cxx1y.html 6116 15. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3639.html 6117 16. http://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html 6118 17. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2011 6119 18. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 6120 19. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 6121 20. https://sourceware.org/gdb/current/onlinedocs/gdb/Xmethods-In-Python.html 6122 21. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Error-and-Warning-Options.html 6123 22. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Language-Independent-Options.html 6124 23. https://gcc.gnu.org/install/configure.html 6125 24. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Thread-safety-of-the-runtime-library.html 6126 25. https://gcc.gnu.org/wiki/Fortran2003Status 6127 26. https://gcc.gnu.org/wiki/Fortran2008Status 6128 27. https://gcc.gnu.org/wiki/Coarray 6129 28. http://www.opencoarrays.org/ 6130 29. https://pkg.go.dev/cmd/go 6131 30. https://pkg.go.dev/cmd/gofmt 6132 31. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/index.html 6133 32. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/cp/index.html 6134 33. https://github.com/davidmalcolm/pygccjit 6135 34. https://github.com/ibuclaw/gccjitd 6136 35. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial04.html 6137 36. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial05.html 6138 37. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 6139 38. https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html 6140 39. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.2 6141 40. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.3 6142 41. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.4 6143 42. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.5 6144 43. https://www.intel.com/content/www/us/en/developer/articles/technical/deprecate-pcommit-instruction.html 6145 44. https://gcc.gnu.org/onlinedocs/ 6146 45. mailto:gcc-help (a] gcc.gnu.org 6147 46. mailto:gcc (a] gcc.gnu.org 6148 47. https://gcc.gnu.org/lists.html 6149 48. https://www.fsf.org/ 6150 49. https://gcc.gnu.org/about.html 6151 50. http://validator.w3.org/check/referer 6152 ====================================================================== 6153 http://gcc.gnu.org/gcc-4.9/index.html 6154 GCC 4.9 Release Series 6155 6156 (This release series is no longer supported.) 6157 6158 Aug 3, 2016 6159 6160 The [1]GNU project and the GCC developers are pleased to announce the 6161 release of GCC 4.9.4. 6162 6163 This release is a bug-fix release, containing fixes for regressions in 6164 GCC 4.9.3 relative to previous releases of GCC. 6165 6166 Release History 6167 6168 GCC 4.9.4 6169 Aug 3, 2016 ([2]changes, [3]documentation) 6170 6171 GCC 4.9.3 6172 June 26, 2015 ([4]changes, [5]documentation) 6173 6174 GCC 4.9.2 6175 October 30, 2014 ([6]changes, [7]documentation) 6176 6177 GCC 4.9.1 6178 July 16, 2014 ([8]changes, [9]documentation) 6179 6180 GCC 4.9.0 6181 April 22, 2014 ([10]changes, [11]documentation) 6182 6183 References and Acknowledgements 6184 6185 GCC used to stand for the GNU C Compiler, but since the compiler 6186 supports several other languages aside from C, it now stands for the 6187 GNU Compiler Collection. 6188 6189 A list of [12]successful builds is updated as new information becomes 6190 available. 6191 6192 The GCC developers would like to thank the numerous people that have 6193 contributed new features, improvements, bug fixes, and other changes as 6194 well as test results to GCC. This [13]amazing group of volunteers is 6195 what makes GCC successful. 6196 6197 For additional information about GCC please refer to the [14]GCC 6198 project web site or contact the [15]GCC development mailing list. 6199 6200 To obtain GCC please use [16]our mirror sites or [17]our version 6201 control system. 6202 6203 6204 For questions related to the use of GCC, please consult these web 6205 pages and the [18]GCC manuals. If that fails, the 6206 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6207 web pages and the development of GCC are welcome on our developer 6208 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 6209 archives. 6210 6211 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 6212 distribution of this entire article is permitted in any medium, 6213 provided this notice is preserved. 6214 6215 These pages are [23]maintained by the GCC team. Last modified 6216 2021-07-28[24]. 6217 6218 References 6219 6220 1. http://www.gnu.org/ 6221 2. http://gcc.gnu.org/gcc-4.9/changes.html 6222 3. http://gcc.gnu.org/onlinedocs/4.9.4/ 6223 4. http://gcc.gnu.org/gcc-4.9/changes.html 6224 5. http://gcc.gnu.org/onlinedocs/4.9.3/ 6225 6. http://gcc.gnu.org/gcc-4.9/changes.html 6226 7. http://gcc.gnu.org/onlinedocs/4.9.2/ 6227 8. http://gcc.gnu.org/gcc-4.9/changes.html 6228 9. http://gcc.gnu.org/onlinedocs/4.9.1/ 6229 10. http://gcc.gnu.org/gcc-4.9/changes.html 6230 11. https://gcc.gnu.org/onlinedocs/4.9.0/ 6231 12. http://gcc.gnu.org/gcc-4.9/buildstat.html 6232 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 6233 14. http://gcc.gnu.org/index.html 6234 15. mailto:gcc (a] gcc.gnu.org 6235 16. http://gcc.gnu.org/mirrors.html 6236 17. http://gcc.gnu.org/git.html 6237 18. https://gcc.gnu.org/onlinedocs/ 6238 19. mailto:gcc-help (a] gcc.gnu.org 6239 20. mailto:gcc (a] gcc.gnu.org 6240 21. https://gcc.gnu.org/lists.html 6241 22. https://www.fsf.org/ 6242 23. https://gcc.gnu.org/about.html 6243 24. http://validator.w3.org/check/referer 6244 ====================================================================== 6245 http://gcc.gnu.org/gcc-4.9/changes.html 6246 GCC 4.9 Release Series 6247 Changes, New Features, and Fixes 6248 6249 Caveats 6250 6251 * The mudflap run time checker has been removed. The mudflap options 6252 remain, but do nothing. 6253 * Support for a number of older systems and recently unmaintained or 6254 untested target ports of GCC has been declared obsolete in GCC 4.9. 6255 Unless there is activity to revive them, the next release of GCC 6256 will have their sources permanently removed. 6257 The following ports for individual systems on particular 6258 architectures have been obsoleted: 6259 + Solaris 9 (*-*-solaris2.9). Details can be found in the 6260 [1]announcement. 6261 * On AArch64, the singleton vector types int64x1_t, uint64x1_t and 6262 float64x1_t exported by arm_neon.h are defined to be the same as 6263 their base types. This results in incorrect application of 6264 parameter passing rules to arguments of types int64x1_t and 6265 uint64x1_t, with respect to the AAPCS64 ABI specification. In 6266 addition, names of C++ functions with parameters of these types 6267 (including float64x1_t) are not mangled correctly. The current 6268 typedef declarations also unintentionally allow implicit casting 6269 between singleton vector types and their base types. These issues 6270 will be resolved in a near future release. See [2]PR60825 for more 6271 information. 6272 6273 More information on porting to GCC 4.9 from previous versions of GCC 6274 can be found in the [3]porting guide for this release. 6275 6276 General Optimizer Improvements 6277 6278 * AddressSanitizer, a fast memory error detector, is now available on 6279 ARM. 6280 * UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior 6281 detector, has been added and can be enabled via 6282 -fsanitize=undefined. Various computations will be instrumented to 6283 detect undefined behavior at runtime. UndefinedBehaviorSanitizer is 6284 currently available for the C and C++ languages. 6285 * Link-time optimization (LTO) improvements: 6286 + Type merging was rewritten. The new implementation is 6287 significantly faster and uses less memory. 6288 + Better partitioning algorithm resulting in less streaming 6289 during link time. 6290 + Early removal of virtual methods reduces the size of object 6291 files and improves link-time memory usage and compile time. 6292 + Function bodies are now loaded on-demand and released early 6293 improving overall memory usage at link time. 6294 + C++ hidden keyed methods can now be optimized out. 6295 + When using a linker plugin, compiling with the -flto option 6296 now generates slim object files (.o) which only contain 6297 intermediate language representation for LTO. Use 6298 -ffat-lto-objects to create files which contain additionally 6299 the object code. To generate static libraries suitable for LTO 6300 processing, use gcc-ar and gcc-ranlib; to list symbols from a 6301 slim object file use gcc-nm. (This requires that ar, ranlib 6302 and nm have been compiled with plugin support.) 6303 Memory usage building Firefox with debug enabled was reduced from 6304 15GB to 3.5GB; link time from 1700 seconds to 350 seconds. 6305 * Inter-procedural optimization improvements: 6306 + New type inheritance analysis module improving 6307 devirtualization. Devirtualization now takes into account 6308 anonymous name-spaces and the C++11 final keyword. 6309 + New speculative devirtualization pass (controlled by 6310 -fdevirtualize-speculatively. 6311 + Calls that were speculatively made direct are turned back to 6312 indirect where direct call is not cheaper. 6313 + Local aliases are introduced for symbols that are known to be 6314 semantically equivalent across shared libraries improving 6315 dynamic linking times. 6316 * Feedback directed optimization improvements: 6317 + Profiling of programs using C++ inline functions is now more 6318 reliable. 6319 + New time profiling determines typical order in which functions 6320 are executed. 6321 + A new function reordering pass (controlled by 6322 -freorder-functions) significantly reduces startup time of 6323 large applications. Until binutils support is completed, it is 6324 effective only with link-time optimization. 6325 + Feedback driven indirect call removal and devirtualization now 6326 handle cross-module calls when link-time optimization is 6327 enabled. 6328 6329 New Languages and Language specific improvements 6330 6331 * Version 4.0 of the [4]OpenMP specification is now supported in the 6332 C and C++ compilers and starting with the 4.9.1 release also in the 6333 Fortran compiler. The new -fopenmp-simd option can be used to 6334 enable OpenMP's SIMD directives while ignoring other OpenMP 6335 directives. The new [5]-fsimd-cost-model= option permits to tune 6336 the vectorization cost model for loops annotated with OpenMP and 6337 Cilk Plus simd directives. -Wopenmp-simd warns when the current 6338 cost model overrides simd directives set by the user. 6339 * The -Wdate-time option has been added for the C, C++ and Fortran 6340 compilers, which warns when the __DATE__, __TIME__ or __TIMESTAMP__ 6341 macros are used. Those macros might prevent bit-wise-identical 6342 reproducible compilations. 6343 6344 Ada 6345 6346 * GNAT switched to Ada 2012 instead of Ada 2005 by default. 6347 6348 C family 6349 6350 * Support for colorizing diagnostics emitted by GCC has been added. 6351 The [6]-fdiagnostics-color=auto will enable it when outputting to 6352 terminals, -fdiagnostics-color=always unconditionally. The 6353 GCC_COLORS environment variable can be used to customize the colors 6354 or disable coloring. If GCC_COLORS variable is present in the 6355 environment, the default is -fdiagnostics-color=auto, otherwise 6356 -fdiagnostics-color=never. 6357 Sample diagnostics output: 6358 $ g++ -fdiagnostics-color=always -S -Wall test.C 6359 test.C: In function int foo(): 6360 test.C:1:14: warning: no return statement in function returning non-void [-W 6361 return-type] 6362 int foo () { } 6363 ^ 6364 test.C:2:46: error: template instantiation depth exceeds maximum of 900 (use 6365 -ftemplate-depth= to increase the maximum) instantiating struct X<100> 6366 template <int N> struct X { static const int value = X<N-1>::value; }; temp 6367 late struct X<1000>; 6368 ^ 6369 test.C:2:46: recursively required from const int X<999>::value 6370 test.C:2:46: required from const int X<1000>::value 6371 test.C:2:88: required from here 6372 6373 test.C:2:46: error: incomplete type X<100> used in nested name specifier 6374 6375 * With the new [7]#pragma GCC ivdep, the user can assert that there 6376 are no loop-carried dependencies which would prevent concurrent 6377 execution of consecutive iterations using SIMD (single instruction 6378 multiple data) instructions. 6379 * Support for Cilk Plus has been added and can be enabled with the 6380 -fcilkplus option. Cilk Plus is an extension to the C and C++ 6381 languages to support data and task parallelism. The present 6382 implementation follows ABI version 1.2; all features but _Cilk_for 6383 have been implemented. 6384 6385 C 6386 6387 * ISO C11 atomics (the _Atomic type specifier and qualifier and the 6388 <stdatomic.h> header) are now supported. 6389 * ISO C11 generic selections (_Generic keyword) are now supported. 6390 * ISO C11 thread-local storage (_Thread_local, similar to GNU C 6391 __thread) is now supported. 6392 * ISO C11 support is now at a similar level of completeness to ISO 6393 C99 support: substantially complete modulo bugs, extended 6394 identifiers (supported except for corner cases when 6395 -fextended-identifiers is used), floating-point issues (mainly but 6396 not entirely relating to optional C99 features from Annexes F and 6397 G) and the optional Annexes K (Bounds-checking interfaces) and L 6398 (Analyzability). 6399 * A new C extension __auto_type provides a subset of the 6400 functionality of C++11 auto in GNU C. 6401 6402 C++ 6403 6404 * The G++ implementation of [8]C++1y return type deduction for normal 6405 functions has been updated to conform to [9]N3638, the proposal 6406 accepted into the working paper. Most notably, it adds 6407 decltype(auto) for getting decltype semantics rather than the 6408 template argument deduction semantics of plain auto: 6409 6410 int& f(); 6411 auto i1 = f(); // int 6412 decltype(auto) i2 = f(); // int& 6413 6414 * G++ supports [10]C++1y lambda capture initializers: 6415 6416 [x = 42]{ ... }; 6417 6418 Actually, they have been accepted since GCC 4.5, but now the 6419 compiler doesn't warn about them with -std=c++1y, and supports 6420 parenthesized and brace-enclosed initializers as well. 6421 * G++ supports [11]C++1y variable length arrays. G++ has supported 6422 GNU/C99-style VLAs for a long time, but now additionally supports 6423 initializers and lambda capture by reference. In C++1y mode G++ 6424 will complain about VLA uses that are not permitted by the draft 6425 standard, such as forming a pointer to VLA type or applying sizeof 6426 to a VLA variable. Note that it now appears that VLAs will not be 6427 part of C++14, but will be part of a separate document and then 6428 perhaps C++17. 6429 6430 void f(int n) { 6431 int a[n] = { 1, 2, 3 }; // throws std::bad_array_length if n < 3 6432 [&a]{ for (int i : a) { cout << i << endl; } }(); 6433 &a; // error, taking address of VLA 6434 } 6435 6436 * G++ supports the [12]C++1y [[deprecated]] attribute modulo bugs in 6437 the underlying [[gnu::deprecated]] attribute. Classes and functions 6438 can be marked deprecated and a diagnostic message added: 6439 6440 class A; 6441 int bar(int n); 6442 #if __cplusplus > 201103 6443 class [[deprecated("A is deprecated in C++14; Use B instead")]] A; 6444 [[deprecated("bar is unsafe; use foo() instead")]] 6445 int bar(int n); 6446 6447 int foo(int n); 6448 class B; 6449 #endif 6450 A aa; // warning: 'A' is deprecated : A is deprecated in C++14; Use B instead 6451 int j = bar(2); // warning: 'int bar(int)' is deprecated : bar is unsafe; use fo 6452 o() instead 6453 6454 * G++ supports [13]C++1y digit separators. Long numeric literals can 6455 be subdivided with a single quote ' to enhance readability: 6456 6457 int i = 1048576; 6458 int j = 1'048'576; 6459 int k = 0x10'0000; 6460 int m = 0'004'000'000; 6461 int n = 0b0001'0000'0000'0000'0000'0000; 6462 6463 double x = 1.602'176'565e-19; 6464 double y = 1.602'176'565e-1'9; 6465 6466 * G++ supports [14]C++1y generic (polymorphic) lambdas. 6467 6468 // a functional object that will increment any type 6469 auto incr = [](auto x) { return x++; }; 6470 6471 * As a GNU extension, G++ supports explicit template parameter syntax 6472 for generic lambdas. This can be combined in the expected way with 6473 the standard auto syntax. 6474 6475 // a functional object that will add two like-type objects 6476 auto add = [] <typename T> (T a, T b) { return a + b; }; 6477 6478 * G++ supports unconstrained generic functions as specified by 4.1.2 6479 and 5.1.1 of [15]N3889: Concepts Lite Specification. Briefly, auto 6480 may be used as a type-specifier in a parameter declaration of any 6481 function declarator in order to introduce an implicit function 6482 template parameter, akin to generic lambdas. 6483 6484 // the following two function declarations are equivalent 6485 auto incr(auto x) { return x++; } 6486 template <typename T> 6487 auto incr(T x) { return x++; } 6488 6489 Runtime Library (libstdc++) 6490 6491 * [16]Improved support for C++11, including: 6492 + support for <regex>; 6493 + The associative containers in <map> and <set> and the 6494 unordered associative containers in <unordered_map> and 6495 <unordered_set> meet the allocator-aware container 6496 requirements; 6497 * [17]Improved experimental support for the upcoming ISO C++ 6498 standard, C++14, including: 6499 + fixing constexpr member functions without const; 6500 + implementation of the std::exchange() utility function; 6501 + addressing tuples by type; 6502 + implemention of std::make_unique; 6503 + implemention of std::shared_lock; 6504 + making std::result_of SFINAE-friendly; 6505 + adding operator() to std::integral_constant; 6506 + adding user-defined literals for standard library types 6507 std::basic_string, std::chrono::duration, and std::complex; 6508 + adding two range overloads to non-modifying sequence oprations 6509 std::equal and std::mismatch; 6510 + adding IO manipulators for quoted strings; 6511 + adding constexpr members to <utility>, <complex>, <chrono>, 6512 and some containers; 6513 + adding compile-time std::integer_sequence; 6514 + adding cleaner transformation traits; 6515 + making <functional>s operator functors easier to use and more 6516 generic; 6517 * An implementation of std::experimental::optional. 6518 * An implementation of std::experimental::string_view. 6519 * The non-standard function std::copy_exception has been deprecated 6520 and will be removed in a future version. std::make_exception_ptr 6521 should be used instead. 6522 6523 Fortran 6524 6525 * Compatibility notice: 6526 + Module files: The version of the module files (.mod) has been 6527 incremented; additionally, module files are now compressed. 6528 Fortran MODULEs compiled by earlier GCC versions have to be 6529 recompiled, when they are USEd by files compiled with GCC 4.9. 6530 GCC 4.9 is not able to read .mod files of earlier GCC 6531 versions; attempting to do so gives an error message. Note: 6532 The ABI of the produced assembler data itself has not changed: 6533 object files and libraries are fully compatible with older 6534 versions (except as stated below). 6535 + ABI changes: 6536 o The [18]argument passing ABI has changed for scalar dummy 6537 arguments of type INTEGER, REAL, COMPLEX and LOGICAL, 6538 which have both the VALUE and the OPTIONAL attributes. 6539 o To support finalization the virtual table associated with 6540 polymorphic variables has changed. Code containing CLASS 6541 should be recompiled, including all files which define 6542 derived types involved in the type definition used by 6543 polymorphic variables. (Note: Due to the incremented 6544 module version, trying to mix old code with new code will 6545 usually give an error message.) 6546 + GNU Fortran no longer deallocates allocatable variables or 6547 allocatable components of variables declared in the main 6548 program. Since Fortran 2008, the standard explicitly states 6549 that variables declared in the Fortran main program 6550 automatically have the SAVE attribute. 6551 + When opening files, the close-on-exec flag is set if the 6552 system supports such a feature. This is generally considered 6553 good practice these days, but if there is a need to pass file 6554 descriptors to child processes the parent process must now 6555 remember to clear the close-on-exec flag by calling fcntl(), 6556 e.g. via ISO_C_BINDING, before executing the child process. 6557 * The deprecated command-line option -fno-whole-file has been 6558 removed. (-fwhole-file is the default since GCC 4.6.) 6559 -fwhole-file/-fno-whole-file continue to be accepted but do not 6560 influence the code generation. 6561 * The compiler no longer unconditionally warns about DO loops with 6562 zero iterations. This warning is now controlled by the -Wzerotrip 6563 option, which is implied by -Wall. 6564 * The new NO_ARG_CHECK attribute of the [19]!GCC$ directive can be 6565 used to disable the type-kind-rank (TKR) argument check for a dummy 6566 argument. The feature is similar to ISO/IEC TS 29133:2012's 6567 TYPE(*), except that it additionally also disables the rank check. 6568 Variables with NO_ARG_CHECK have to be dummy arguments and may only 6569 be used as argument to ISO_C_BINDING's C_LOC and as actual argument 6570 to another NO_ARG_CHECK dummy argument; also the other constraints 6571 of TYPE(*) apply. The dummy arguments should be declared as scalar 6572 or assumed-size variable of type type(*) (recommended) or of type 6573 integer, real, complex or logical. With NO_ARG_CHECK, a pointer to 6574 the data without further type or shape information is passed, 6575 similar to C's void*. Note that also TS 29113's 6576 type(*),dimension(..) accepts arguments of any type and rank; 6577 contrary to NO_ARG_CHECK assumed-rank arguments pass an array 6578 descriptor which contains the array shape and stride of the 6579 argument. 6580 * [20]Fortran 2003: 6581 + Finalization is now supported. It is currently only done for a 6582 subset of those situations in which it should occur. 6583 + Experimental support for scalar character components with 6584 deferred length (i.e. allocatable string length) in derived 6585 types has been added. (Deferred-length character variables are 6586 supported since GCC 4.6.) 6587 * [21]Fortran 2008: 6588 + When STOP or ERROR STOP are used to terminate the execution 6589 and any exception (but inexact) is signaling, a warning is 6590 printed to ERROR_UNIT, indicating which exceptions are 6591 signaling. The [22]-ffpe-summary= command-line option can be 6592 used to fine-tune for which exceptions the warning should be 6593 shown. 6594 + Rounding on input (READ) is now handled on systems where 6595 strtod honours the rounding mode. (For output, rounding is 6596 supported since GCC 4.5.) Note that for input, the compatible 6597 rounding mode is handled as nearest (i.e., rounding to an even 6598 least significant [cf. IEC 60559:1989] for a tie, while 6599 compatible rounds away from zero in that case). 6600 6601 Go 6602 6603 * GCC 4.9 provides a complete implementation of the Go 1.2.1 release. 6604 6605 New Targets and Target Specific Improvements 6606 6607 AArch64 6608 6609 * The ARMv8-A crypto and CRC instructions are now supported through 6610 intrinsics. These are enabled when the architecture supports these 6611 and are available through the -march=armv8-a+crc and 6612 -march=armv8-a+crypto options. 6613 * Initial support for ILP32 has now been added to the compiler. This 6614 is now available through the command-line option -mabi=ilp32. 6615 Support for ILP32 is considered experimental as the ABI 6616 specification is still beta. 6617 * Coverage of more of the ISA including the SIMD extensions has been 6618 added. The Advanced SIMD intrinsics have also been improved. 6619 * The new local register allocator (LRA) is now on by default for the 6620 AArch64 backend. 6621 * The REE (Redundant extension elimination) pass has now been enabled 6622 by default for the AArch64 backend. 6623 * Tuning for the Cortex-A53 and Cortex-A57 has been improved. 6624 * Initial big.LITTLE tuning support for the combination of Cortex-A57 6625 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 6626 option. 6627 * A number of structural changes have been made to both the ARM and 6628 AArch64 backends to facilitate improved code-generation. 6629 * As of GCC 4.9.2 a workaround for the ARM Cortex-A53 erratum 835769 6630 has been added and can be enabled by giving the 6631 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 6632 default by configuring GCC with the --enable-fix-cortex-a53-835769 6633 option. 6634 6635 ARC 6636 6637 * A port for Synopsys Designware ARC has been contributed by Embecosm 6638 and Synopsys Inc. 6639 6640 ARM 6641 6642 * Use of Advanced SIMD (Neon) for 64-bit scalar computations has been 6643 disabled by default. This was found to generate better code in only 6644 a small number of cases. It can be turned back on with the 6645 -mneon-for-64bits option. 6646 * Further support for the ARMv8-A architecture, notably implementing 6647 the restriction around IT blocks in the Thumb32 instruction set has 6648 been added. The -mrestrict-it option can be used with 6649 -march=armv7-a or the -march=armv7ve options to make code 6650 generation fully compatible with the deprecated instructions in 6651 ARMv8-A. 6652 * Support has now been added for the ARMv7ve variant of the 6653 architecture. This can be used by the -march=armv7ve option. 6654 * The ARMv8-A crypto and CRC instructions are now supported through 6655 intrinsics and are available through the -march=armv8-a+crc and 6656 mfpu=crypto-neon-fp-armv8 options. 6657 * LRA is now on by default for the ARM target. This can be turned off 6658 using the -mno-lra option. This option is a purely transitionary 6659 command-line option and will be removed in a future release. We are 6660 interested in any bug reports regarding functional and performance 6661 regressions with LRA. 6662 * A new option -mslow-flash-data to improve performance of programs 6663 fetching data on slow flash memory has now been introduced for the 6664 ARMv7-M profile cores. 6665 * A new option -mpic-data-is-text-relative for targets that allows 6666 data segments to be relative to text segments has been added. This 6667 is on by default for all targets except VxWorks RTP. 6668 * A number of infrastructural changes have been made to both the ARM 6669 and AArch64 backends to facilitate improved code-generation. 6670 * GCC now supports Cortex-A12 and the Cortex-R7 through the 6671 -mcpu=cortex-a12 and -mcpu=cortex-r7 options. 6672 * GCC now has tuning for the Cortex-A57 and Cortex-A53 through the 6673 -mcpu=cortex-a57 and -mcpu=cortex-a53 options. 6674 * Initial big.LITTLE tuning support for the combination of Cortex-A57 6675 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 6676 option. Similar support was added for the combination of Cortex-A15 6677 and Cortex-A7 through the -mcpu=cortex-a15.cortex-a7 option. 6678 * Further performance optimizations for the Cortex-A15 and the 6679 Cortex-M4 have been added. 6680 * A number of code generation improvements for Thumb2 to reduce code 6681 size when compiling for the M-profile processors. 6682 6683 AVR 6684 6685 * A new command-line option -mfract-convert-truncate has been added. 6686 It allows compiler to use truncation instead of rounding towards 6687 zero for fractional fixed-point types. 6688 6689 IA-32/x86-64 6690 6691 * -mfpmath=sse is now implied by -ffast-math on all targets where 6692 SSE2 is supported. 6693 * Intel AVX-512 support was added to GCC. That includes inline 6694 assembly support, new registers and extending existing ones, new 6695 intrinsics (covered by corresponding testsuite), and basic 6696 autovectorization. AVX-512 instructions are available via the 6697 following GCC switches: AVX-512 foundation instructions: -mavx512f, 6698 AVX-512 prefetch instructions: -mavx512pf, AVX-512 exponential and 6699 reciprocal instructions: -mavx512er, AVX-512 conflict detection 6700 instructions: -mavx512cd. 6701 * It is now possible to call x86 intrinsics from select functions in 6702 a file that are tagged with the corresponding target attribute 6703 without having to compile the entire file with the -mxxx option. 6704 This improves the usability of x86 intrinsics and is particularly 6705 useful when doing [23]Function Multiversioning. 6706 * GCC now supports the new Intel microarchitecture named Silvermont 6707 through -march=silvermont. 6708 * GCC now supports the new Intel microarchitecture named Broadwell 6709 through -march=broadwell. 6710 * Optimizing for other Intel microarchitectures have been renamed to 6711 -march=nehalem, westmere, sandybridge, ivybridge, haswell, bonnell. 6712 * -march=generic has been retuned for better support of Intel core 6713 and AMD Bulldozer architectures. Performance of AMD K7, K8, Intel 6714 Pentium-M, and Pentium4 based CPUs is no longer considered 6715 important for generic. 6716 * -mtune=intel can now be used to generate code running well on the 6717 most current Intel processors, which are Haswell and Silvermont for 6718 GCC 4.9. 6719 * Support to encode 32-bit assembly instructions in 16-bit format is 6720 now available through the -m16 command-line option. 6721 * Better inlining of memcpy and memset that is aware of value ranges 6722 and produces shorter alignment prologues. 6723 * -mno-accumulate-outgoing-args is now honored when unwind 6724 information is output. Argument accumulation is also now turned off 6725 for portions of programs optimized for size. 6726 * Support for new AMD family 15h processors (Excavator core) is now 6727 available through the -march=bdver4 and -mtune=bdver4 options. 6728 6729 MSP430 6730 6731 * A new command-line option -mcpu= has been added to the MSP430 6732 backend. This option is used to specify the ISA to be used. 6733 Accepted values are msp430 (the default), msp430x and msp430xv2. 6734 The ISA is no longer deduced from the -mmcu= option as there are 6735 far too many different MCU names. The -mmcu= option is still 6736 supported, and this is still used to select linker scripts and 6737 generate a C preprocessor symbol that will be recognised by the 6738 msp430.h header file. 6739 6740 NDS32 6741 6742 * A new nds32 port supports the 32-bit architecture from Andes 6743 Technology Corporation. 6744 * The port provides initial support for the V2, V3, V3m instruction 6745 set architectures. 6746 6747 Nios II 6748 6749 * A port for the Altera Nios II has been contributed by Mentor 6750 Graphics. 6751 6752 PowerPC / PowerPC64 / RS6000 6753 6754 * GCC now supports Power ISA 2.07, which includes support for 6755 Hardware Transactional Memory (HTM), Quadword atomics and several 6756 VMX and VSX additions, including Crypto, 64-bit integer, 128-bit 6757 integer and decimal integer operations. 6758 * Support for the POWER8 processor is now available through the 6759 -mcpu=power8 and -mtune=power8 options. 6760 * The libitm library has been modified to add a HTM fastpath that 6761 automatically uses POWER's HTM hardware instructions when it is 6762 executing on a HTM enabled processor. 6763 * Support for the new powerpc64le-linux platform has been added. It 6764 defaults to generating code that conforms to the ELFV2 ABI. 6765 6766 S/390, System z 6767 6768 * Support for the Transactional Execution Facility included with the 6769 IBM zEnterprise zEC12 processor has been added. A set of GCC style 6770 builtins as well as XLC style builtins are provided. The builtins 6771 are enabled by default when using the -march=zEC12 option but can 6772 explicitly be disabled with -mno-htm. Using the GCC builtins also 6773 libitm supports hardware transactions on S/390. 6774 * The hotpatch features allows to prepare functions for hotpatching. 6775 A certain amount of bytes is reserved before the function entry 6776 label plus a NOP is inserted at its very beginning to implement a 6777 backward jump when applying a patch. The feature can either be 6778 enabled per compilation unit via the command-line option -mhotpatch 6779 or per function using the hotpatch attribute. 6780 * The shrink wrap optimization is now supported on S/390 and enabled 6781 by default. 6782 * A major rework of the routines to determine which registers need to 6783 be saved and restored in function prologue/epilogue now allow to 6784 use floating point registers as save slots. This will happen for 6785 certain leaf function with -march=z10 or higher. 6786 * The LRA rtl pass replaces reload by default on S/390. 6787 6788 RX 6789 6790 * The port now allows to specify the RX100, RX200, and RX600 6791 processors with the command-line options -mcpu=rx100, -mcpu=rx200 6792 and -mcpu=rx600. 6793 6794 SH 6795 6796 * Minor improvements to code generated for integer arithmetic and 6797 code that involves the T bit. 6798 * Added support for the SH2A clips and clipu instructions. The 6799 compiler will now try to utilize them for min/max expressions such 6800 as max (-128, min (127, x)). 6801 * Added support for the cmp/str instruction through built-in 6802 functions such as __builtin_strlen. When not optimizing for size, 6803 the compiler will now expand calls to e.g. strlen as an inlined 6804 sequences which utilize the cmp/str instruction. 6805 * Improved code generated around volatile memory loads and stores. 6806 * The option -mcbranchdi has been deprecated. Specifying it will 6807 result in a warning and will not influence code generation. 6808 * The option -mcmpeqdi has been deprecated. Specifying it will result 6809 in a warning and will not influence code generation. 6810 6811 GCC 4.9.1 6812 6813 This is the [24]list of problem reports (PRs) from GCC's bug tracking 6814 system that are known to be fixed in the 4.9.1 release. This list might 6815 not be complete (that is, it is possible that some PRs that have been 6816 fixed are not listed here). 6817 6818 Version 4.0 of the OpenMP specification is supported even in Fortran, 6819 not just C and C++. 6820 6821 GCC 4.9.2 6822 6823 This is the [25]list of problem reports (PRs) from GCC's bug tracking 6824 system that are known to be fixed in the 4.9.2 release. This list might 6825 not be complete (that is, it is possible that some PRs that have been 6826 fixed are not listed here). 6827 6828 GCC 4.9.3 6829 6830 This is the [26]list of problem reports (PRs) from GCC's bug tracking 6831 system that are known to be fixed in the 4.9.3 release. This list might 6832 not be complete (that is, it is possible that some PRs that have been 6833 fixed are not listed here). 6834 6835 GCC 4.9.4 6836 6837 This is the [27]list of problem reports (PRs) from GCC's bug tracking 6838 system that are known to be fixed in the 4.9.4 release. This list might 6839 not be complete (that is, it is possible that some PRs that have been 6840 fixed are not listed here). 6841 6842 6843 For questions related to the use of GCC, please consult these web 6844 pages and the [28]GCC manuals. If that fails, the 6845 [29]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6846 web pages and the development of GCC are welcome on our developer 6847 list at [30]gcc (a] gcc.gnu.org. All of [31]our lists have public 6848 archives. 6849 6850 Copyright (C) [32]Free Software Foundation, Inc. Verbatim copying and 6851 distribution of this entire article is permitted in any medium, 6852 provided this notice is preserved. 6853 6854 These pages are [33]maintained by the GCC team. Last modified 6855 2021-07-28[34]. 6856 6857 References 6858 6859 1. https://gcc.gnu.org/ml/gcc-patches/2013-05/msg00728.html 6860 2. https://gcc.gnu.org/PR60825 6861 3. https://gcc.gnu.org/gcc-4.9/porting_to.html 6862 4. https://www.openmp.org/specifications/ 6863 5. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Optimize-Options.html#index-fsimd-cost-model-908 6864 6. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Language-Independent-Options.html#index-fdiagnostics-color-252 6865 7. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Loop-Specific-Pragmas.html 6866 8. http://gcc.gnu.org/projects/cxx1y.html 6867 9. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3638.html 6868 10. http://gcc.gnu.org/projects/cxx1y.html 6869 11. http://gcc.gnu.org/projects/cxx1y.html 6870 12. http://gcc.gnu.org/projects/cxx1y.html 6871 13. http://gcc.gnu.org/projects/cxx1y.html 6872 14. http://gcc.gnu.org/projects/cxx1y.html 6873 15. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3889.pdf 6874 16. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/libstdc++/manual/manual/status.html#status.iso.2011 6875 17. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2014 6876 18. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Argument-passing-conventions.html 6877 19. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/GNU-Fortran-Compiler-Directives.html 6878 20. https://gcc.gnu.org/wiki/Fortran2003Status 6879 21. https://gcc.gnu.org/wiki/Fortran2008Status 6880 22. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Debugging-Options.html 6881 23. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Function-Multiversioning.html 6882 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.1 6883 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.2 6884 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.3 6885 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.4 6886 28. https://gcc.gnu.org/onlinedocs/ 6887 29. mailto:gcc-help (a] gcc.gnu.org 6888 30. mailto:gcc (a] gcc.gnu.org 6889 31. https://gcc.gnu.org/lists.html 6890 32. https://www.fsf.org/ 6891 33. https://gcc.gnu.org/about.html 6892 34. http://validator.w3.org/check/referer 6893 ====================================================================== 6894 http://gcc.gnu.org/gcc-4.8/index.html 6895 GCC 4.8 Release Series 6896 6897 (This release series is no longer supported.) 6898 6899 June 23, 2015 6900 6901 The [1]GNU project and the GCC developers are pleased to announce the 6902 release of GCC 4.8.5. 6903 6904 This release is a bug-fix release, containing fixes for regressions in 6905 GCC 4.8.4 relative to previous releases of GCC. 6906 6907 Release History 6908 6909 GCC 4.8.5 6910 June 23, 2015 ([2]changes, [3]documentation) 6911 6912 GCC 4.8.4 6913 December 19, 2014 ([4]changes, [5]documentation) 6914 6915 GCC 4.8.3 6916 May 22, 2014 ([6]changes, [7]documentation) 6917 6918 GCC 4.8.2 6919 October 16, 2013 ([8]changes, [9]documentation) 6920 6921 GCC 4.8.1 6922 May 31, 2013 ([10]changes, [11]documentation) 6923 6924 GCC 4.8.0 6925 March 22, 2013 ([12]changes, [13]documentation) 6926 6927 References and Acknowledgements 6928 6929 GCC used to stand for the GNU C Compiler, but since the compiler 6930 supports several other languages aside from C, it now stands for the 6931 GNU Compiler Collection. 6932 6933 A list of [14]successful builds is updated as new information becomes 6934 available. 6935 6936 The GCC developers would like to thank the numerous people that have 6937 contributed new features, improvements, bug fixes, and other changes as 6938 well as test results to GCC. This [15]amazing group of volunteers is 6939 what makes GCC successful. 6940 6941 For additional information about GCC please refer to the [16]GCC 6942 project web site or contact the [17]GCC development mailing list. 6943 6944 To obtain GCC please use [18]our mirror sites or [19]our version 6945 control system. 6946 6947 6948 For questions related to the use of GCC, please consult these web 6949 pages and the [20]GCC manuals. If that fails, the 6950 [21]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6951 web pages and the development of GCC are welcome on our developer 6952 list at [22]gcc (a] gcc.gnu.org. All of [23]our lists have public 6953 archives. 6954 6955 Copyright (C) [24]Free Software Foundation, Inc. Verbatim copying and 6956 distribution of this entire article is permitted in any medium, 6957 provided this notice is preserved. 6958 6959 These pages are [25]maintained by the GCC team. Last modified 6960 2021-07-28[26]. 6961 6962 References 6963 6964 1. http://www.gnu.org/ 6965 2. http://gcc.gnu.org/gcc-4.8/changes.html 6966 3. https://gcc.gnu.org/onlinedocs/4.8.5/ 6967 4. http://gcc.gnu.org/gcc-4.8/changes.html 6968 5. https://gcc.gnu.org/onlinedocs/4.8.4/ 6969 6. http://gcc.gnu.org/gcc-4.8/changes.html 6970 7. https://gcc.gnu.org/onlinedocs/4.8.3/ 6971 8. http://gcc.gnu.org/gcc-4.8/changes.html 6972 9. https://gcc.gnu.org/onlinedocs/4.8.2/ 6973 10. http://gcc.gnu.org/gcc-4.8/changes.html 6974 11. https://gcc.gnu.org/onlinedocs/4.8.1/ 6975 12. http://gcc.gnu.org/gcc-4.8/changes.html 6976 13. https://gcc.gnu.org/onlinedocs/4.8.0/ 6977 14. http://gcc.gnu.org/gcc-4.8/buildstat.html 6978 15. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 6979 16. http://gcc.gnu.org/index.html 6980 17. mailto:gcc (a] gcc.gnu.org 6981 18. http://gcc.gnu.org/mirrors.html 6982 19. http://gcc.gnu.org/git.html 6983 20. https://gcc.gnu.org/onlinedocs/ 6984 21. mailto:gcc-help (a] gcc.gnu.org 6985 22. mailto:gcc (a] gcc.gnu.org 6986 23. https://gcc.gnu.org/lists.html 6987 24. https://www.fsf.org/ 6988 25. https://gcc.gnu.org/about.html 6989 26. http://validator.w3.org/check/referer 6990 ====================================================================== 6991 http://gcc.gnu.org/gcc-4.8/changes.html 6992 GCC 4.8 Release Series 6993 Changes, New Features, and Fixes 6994 6995 Caveats 6996 6997 GCC now uses C++ as its implementation language. This means that to 6998 build GCC from sources, you will need a C++ compiler that understands 6999 C++ 2003. For more details on the rationale and specific changes, 7000 please refer to the [1]C++ conversion page. 7001 7002 To enable the Graphite framework for loop optimizations you now need 7003 CLooG version 0.18.0 and ISL version 0.11.1. Both can be obtained from 7004 the [2]GCC infrastructure directory. The installation manual contains 7005 more information about requirements to build GCC. 7006 7007 GCC now uses a more aggressive analysis to derive an upper bound for 7008 the number of iterations of loops using constraints imposed by language 7009 standards. This may cause non-conforming programs to no longer work as 7010 expected, such as SPEC CPU 2006 464.h264ref and 416.gamess. A new 7011 option, -fno-aggressive-loop-optimizations, was added to disable this 7012 aggressive analysis. In some loops that have known constant number of 7013 iterations, but undefined behavior is known to occur in the loop before 7014 reaching or during the last iteration, GCC will warn about the 7015 undefined behavior in the loop instead of deriving lower upper bound of 7016 the number of iterations for the loop. The warning can be disabled with 7017 -Wno-aggressive-loop-optimizations. 7018 7019 On ARM, a bug has been fixed in GCC's implementation of the AAPCS rules 7020 for the layout of vectors that could lead to wrong code being 7021 generated. Vectors larger than 8 bytes in size are now by default 7022 aligned to an 8-byte boundary. This is an ABI change: code that makes 7023 explicit use of vector types may be incompatible with binary objects 7024 built with older versions of GCC. Auto-vectorized code is not affected 7025 by this change. 7026 7027 On AVR, support has been removed for the command-line option 7028 -mshort-calls deprecated in GCC 4.7. 7029 7030 On AVR, the configure option --with-avrlibc supported since GCC 4.7.2 7031 is turned on per default for all non-RTEMS configurations. This option 7032 arranges for a better integration of [3]AVR Libc with avr-gcc. For 7033 technical details, see [4]PR54461. To turn off the option in non-RTEMS 7034 configurations, use --with-avrlibc=no. If the compiler is configured 7035 for RTEMS, the option is always turned off. 7036 7037 More information on porting to GCC 4.8 from previous versions of GCC 7038 can be found in the [5]porting guide for this release. 7039 7040 General Optimizer Improvements (and Changes) 7041 7042 * DWARF4 is now the default when generating DWARF debug information. 7043 When -g is used on a platform that uses DWARF debugging 7044 information, GCC will now default to -gdwarf-4 7045 -fno-debug-types-section. 7046 GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information 7047 consumers support DWARF4 by default. Before GCC 4.8 the default 7048 version used was DWARF2. To make GCC 4.8 generate an older DWARF 7049 version use -g together with -gdwarf-2 or -gdwarf-3. The default 7050 for Darwin and VxWorks is still -gdwarf-2 -gstrict-dwarf. 7051 * A new general optimization level, -Og, has been introduced. It 7052 addresses the need for fast compilation and a superior debugging 7053 experience while providing a reasonable level of run-time 7054 performance. Overall experience for development should be better 7055 than the default optimization level -O0. 7056 * A new option -ftree-partial-pre was added to control the partial 7057 redundancy elimination (PRE) optimization. This option is enabled 7058 by default at the -O3 optimization level, and it makes PRE more 7059 aggressive. 7060 * The option -fconserve-space has been removed; it was no longer 7061 useful on most targets since GCC supports putting variables into 7062 BSS without making them common. 7063 * The struct reorg and matrix reorg optimizations (command-line 7064 options -fipa-struct-reorg and -fipa-matrix-reorg) have been 7065 removed. They did not always work correctly, nor did they work with 7066 link-time optimization (LTO), hence were only applicable to 7067 programs consisting of a single translation unit. 7068 * Several scalability bottle-necks have been removed from GCC's 7069 optimization passes. Compilation of extremely large functions, e.g. 7070 due to the use of the flatten attribute in the "Eigen" C++ linear 7071 algebra templates library, is significantly faster than previous 7072 releases of GCC. 7073 * Link-time optimization (LTO) improvements: 7074 + LTO partitioning has been rewritten for better reliability and 7075 maintanibility. Several important bugs leading to link 7076 failures have been fixed. 7077 * Interprocedural optimization improvements: 7078 + A new symbol table has been implemented. It builds on existing 7079 callgraph and varpool modules and provide a new API. Unusual 7080 symbol visibilities and aliases are handled more consistently 7081 leading to, for example, more aggressive unreachable code 7082 removal with LTO. 7083 + The inline heuristic can now bypass limits on the size of of 7084 inlined functions when the inlining is particularly 7085 profitable. This happens, for example, when loop bounds or 7086 array strides get propagated. 7087 + Values passed through aggregates (either by value or 7088 reference) are now propagated at the inter-procedural level 7089 leading to better inlining decisions (for example in the case 7090 of Fortran array descriptors) and devirtualization. 7091 * [6]AddressSanitizer , a fast memory error detector, has been added 7092 and can be enabled via -fsanitize=address. Memory access 7093 instructions will be instrumented to detect heap-, stack-, and 7094 global-buffer overflow as well as use-after-free bugs. To get nicer 7095 stacktraces, use -fno-omit-frame-pointer. The AddressSanitizer is 7096 available on IA-32/x86-64/x32/PowerPC/PowerPC64 GNU/Linux and on 7097 x86-64 Darwin. 7098 * [7]ThreadSanitizer has been added and can be enabled via 7099 -fsanitize=thread. Instructions will be instrumented to detect data 7100 races. The ThreadSanitizer is available on x86-64 GNU/Linux. 7101 * A new local register allocator (LRA) has been implemented, which 7102 replaces the 26 year old reload pass and improves generated code 7103 quality. For now it is active on the IA-32 and x86-64 targets. 7104 * Support for transactional memory has been implemented on the 7105 following architectures: IA-32/x86-64, ARM, PowerPC, SH, SPARC, and 7106 Alpha. 7107 7108 New Languages and Language specific improvements 7109 7110 C family 7111 7112 * Each diagnostic emitted now includes the original source line and a 7113 caret '^' indicating the column. The option 7114 -fno-diagnostics-show-caret suppresses this information. 7115 * The option -ftrack-macro-expansion=2 is now enabled by default. 7116 This allows the compiler to display the macro expansion stack in 7117 diagnostics. Combined with the caret information, an example 7118 diagnostic showing these two features is: 7119 7120 t.c:1:94: error: invalid operands to binary < (have struct mystruct and float 7121 ) 7122 #define MYMAX(A,B) __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) _ 7123 _b = (B); __a < __b ? __b : __a; }) 7124 7125 ^ 7126 t.c:7:7: note: in expansion of macro 'MYMAX' 7127 X = MYMAX(P, F); 7128 ^ 7129 7130 * A new -Wsizeof-pointer-memaccess warning has been added (also 7131 enabled by -Wall) to warn about suspicious length parameters to 7132 certain string and memory built-in functions if the argument uses 7133 sizeof. This warning warns e.g. about memset (ptr, 0, sizeof 7134 (ptr)); if ptr is not an array, but a pointer, and suggests a 7135 possible fix, or about memcpy (&foo, ptr, sizeof (&foo));. 7136 * The new option -Wpedantic is an alias for -pedantic, which is now 7137 deprecated. The forms -Wno-pedantic, -Werror=pedantic, and 7138 -Wno-error=pedantic work in the same way as for any other -W 7139 option. One caveat is that -Werror=pedantic is not equivalent to 7140 -pedantic-errors, since the latter makes into errors some warnings 7141 that are not controlled by -Wpedantic, and the former only affects 7142 diagnostics that are disabled when using -Wno-pedantic. 7143 * The option -Wshadow no longer warns if a declaration shadows a 7144 function declaration, unless the former declares a function or 7145 pointer to function, because this is [8]a common and valid case in 7146 real-world code. 7147 7148 C++ 7149 7150 * G++ now implements the [9]C++11 thread_local keyword; this differs 7151 from the GNU __thread keyword primarily in that it allows dynamic 7152 initialization and destruction semantics. Unfortunately, this 7153 support requires a run-time penalty for references to 7154 non-function-local thread_local variables defined in a different 7155 translation unit even if they don't need dynamic initialization, so 7156 users may want to continue to use __thread for TLS variables with 7157 static initialization semantics. 7158 If the programmer can be sure that no use of the variable in a 7159 non-defining TU needs to trigger dynamic initialization (either 7160 because the variable is statically initialized, or a use of the 7161 variable in the defining TU will be executed before any uses in 7162 another TU), they can avoid this overhead with the 7163 -fno-extern-tls-init option. 7164 OpenMP threadprivate variables now also support dynamic 7165 initialization and destruction by the same mechanism. 7166 * G++ now implements the [10]C++11 attribute syntax, e.g. 7167 7168 [[noreturn]] void f(); 7169 7170 and also the alignment specifier, e.g. 7171 7172 alignas(double) int i; 7173 7174 * G++ now implements [11]C++11 inheriting constructors, e.g. 7175 7176 struct A { A(int); }; 7177 struct B: A { using A::A; }; // defines B::B(int) 7178 B b(42); // OK 7179 7180 * As of GCC 4.8.1, G++ implements the change to decltype semantics 7181 from [12]N3276. 7182 7183 struct A f(); 7184 decltype(f()) g(); // OK, return type of f() is not required to be complete. 7185 7186 * As of GCC 4.8.1, G++ implements [13]C++11 ref-qualifiers, e.g. 7187 7188 struct A { int f() &; }; 7189 int i = A().f(); // error, f() requires an lvalue object 7190 7191 * G++ now supports a -std=c++1y option for experimentation with 7192 features proposed for the next revision of the standard, expected 7193 around 2014. Currently the only difference from -std=c++11 is 7194 support for return type deduction in normal functions, as proposed 7195 in [14]N3386. Status of C++1y features in GCC 4.8 can be found 7196 [15]here. 7197 * The G++ namespace association extension, __attribute ((strong)), 7198 has been deprecated. Inline namespaces should be used instead. 7199 * G++ now supports a -fext-numeric-literal option to control whether 7200 GNU numeric literal suffixes are accepted as extensions or 7201 processed as C++11 user-defined numeric literal suffixes. The flag 7202 is on (use suffixes for GNU literals) by default for -std=gnu++*, 7203 and -std=c++98. The flag is off (use suffixes for user-defined 7204 literals) by default for -std=c++11 and later. 7205 7206 Runtime Library (libstdc++) 7207 7208 * [16]Improved experimental support for the new ISO C++ standard, 7209 C++11, including: 7210 + forward_list meets the allocator-aware container requirements; 7211 + this_thread::sleep_for(), this_thread::sleep_until() and 7212 this_thread::yield() are defined without requiring the 7213 configure option --enable-libstdcxx-time; 7214 * Improvements to <random>: 7215 + SSE optimized normal_distribution. 7216 + Use of hardware RNG instruction for random_device on new x86 7217 processors (requires the assembler to support the 7218 instruction.) 7219 and <ext/random>: 7220 + New random number engine simd_fast_mersenne_twister_engine 7221 with an optimized SSE implementation. 7222 + New random number distributions beta_distribution, 7223 normal_mv_distribution, rice_distribution, 7224 nakagami_distribution, pareto_distribution, k_distribution, 7225 arcsine_distribution, hoyt_distribution. 7226 * Added --disable-libstdcxx-verbose configure option to disable 7227 diagnostic messages issued when a process terminates abnormally. 7228 This may be useful for embedded systems to reduce the size of 7229 executables that link statically to the library. 7230 7231 Fortran 7232 7233 * Compatibility notice: 7234 + Module files: The version of module files (.mod) has been 7235 incremented. Fortran MODULEs compiled by earlier GCC versions 7236 have to be recompiled, when they are USEd by files compiled 7237 with GCC 4.8. GCC 4.8 is not able to read .mod files created 7238 by earlier versions; attempting to do so gives an error 7239 message. 7240 Note: The ABI of the produced assembler data itself has not 7241 changed; object files and libraries are fully compatible with 7242 older versions except as noted below. 7243 + ABI: Some internal names (used in the assembler/object file) 7244 have changed for symbols declared in the specification part of 7245 a module. If an affected module or a file using it via use 7246 association is recompiled, the module and all files which 7247 directly use such symbols have to be recompiled as well. This 7248 change only affects the following kind of module symbols: 7249 o Procedure pointers. Note: C-interoperable function 7250 pointers (type(c_funptr)) are not affected nor are 7251 procedure-pointer components. 7252 o Deferred-length character strings. 7253 * The [17]BACKTRACE intrinsic subroutine has been added. It shows a 7254 backtrace at an arbitrary place in user code; program execution 7255 continues normally afterwards. 7256 * The [18]-Wc-binding-type warning option has been added (disabled by 7257 default). It warns if the a variable might not be C interoperable; 7258 in particular, if the variable has been declared using an intrinsic 7259 type with default kind instead of using a kind parameter defined 7260 for C interoperability in the intrinsic ISO_C_Binding module. 7261 Before, this warning was always printed. The -Wc-binding-type 7262 option is enabled by -Wall. 7263 * The [19]-Wrealloc-lhs and -Wrealloc-lhs-all warning command-line 7264 options have been added, which diagnose when code is inserted for 7265 automatic (re)allocation of a variable during assignment. This 7266 option can be used to decide whether it is safe to use 7267 [20]-fno-realloc-lhs. Additionally, it can be used to find 7268 automatic (re)allocation in hot loops. (For arrays, replacing 7269 "var=" by "var(:)=" disables the automatic reallocation.) 7270 * The [21]-Wcompare-reals command-line option has been added. When 7271 this is set, warnings are issued when comparing REAL or COMPLEX 7272 types for equality and inequality; consider replacing a == b by 7273 abs(ab) < eps with a suitable eps. -Wcompare-reals is enabled by 7274 -Wextra. 7275 * The [22]-Wtarget-lifetime command-line option has been added 7276 (enabled with -Wall), which warns if the pointer in a pointer 7277 assignment might outlive its target. 7278 * Reading floating point numbers which use "q" for the exponential 7279 (such as 4.0q0) is now supported as vendor extension for better 7280 compatibility with old data files. It is strongly recommended to 7281 use for I/O the equivalent but standard conforming "e" (such as 7282 4.0e0). 7283 (For Fortran source code, consider replacing the "q" in 7284 floating-point literals by a kind parameter (e.g. 4.0e0_qp with a 7285 suitable qp). Note that in Fortran source code replacing "q" by 7286 a simple "e" is not equivalent.) 7287 * The GFORTRAN_TMPDIR environment variable for specifying a 7288 non-default directory for files opened with STATUS="SCRATCH", is 7289 not used anymore. Instead gfortran checks the POSIX/GNU standard 7290 TMPDIR environment variable. If TMPDIR is not defined, gfortran 7291 falls back to other methods to determine the directory for 7292 temporary files as documented in the [23]user manual. 7293 * [24]Fortran 2003: 7294 + Support for unlimited polymorphic variables (CLASS(*)) has 7295 been added. Nonconstant character lengths are not yet 7296 supported. 7297 * [25]TS 29113: 7298 + Assumed types (TYPE(*)) are now supported. 7299 + Experimental support for assumed-rank arrays (dimension(..)) 7300 has been added. Note that currently gfortran's own array 7301 descriptor is used, which is different from the one defined in 7302 TS29113, see [26]gfortran's header file or use the [27]Chasm 7303 Language Interoperability Tools. 7304 7305 Go 7306 7307 * GCC 4.8.2 provides a complete implementation of the Go 1.1.2 7308 release. 7309 * GCC 4.8.0 and 4.8.1 implement a preliminary version of the Go 1.1 7310 release. The library support is not quite complete. 7311 * Go has been tested on GNU/Linux and Solaris platforms for various 7312 processors including x86, x86_64, PowerPC, SPARC, and Alpha. It may 7313 work on other platforms as well. 7314 7315 New Targets and Target Specific Improvements 7316 7317 AArch64 7318 7319 * A new port has been added to support AArch64, the new 64-bit 7320 architecture from ARM. Note that this is a separate port from the 7321 existing 32-bit ARM port. 7322 * The port provides initial support for the Cortex-A53 and the 7323 Cortex-A57 processors with the command line options 7324 -mcpu=cortex-a53 and -mcpu=cortex-a57. 7325 * As of GCC 4.8.4 a workaround for the ARM Cortex-A53 erratum 835769 7326 has been added and can be enabled by giving the 7327 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 7328 default by configuring GCC with the --enable-fix-cortex-a53-835769 7329 option. 7330 7331 ARM 7332 7333 * Initial support has been added for the AArch32 extensions defined 7334 in the ARMv8 architecture. 7335 * Code generation improvements for the Cortex-A7 and Cortex-A15 CPUs. 7336 * A new option, -mcpu=marvell-pj4, has been added to generate code 7337 for the Marvell PJ4 processor. 7338 * The compiler can now automatically generate the VFMA, VFMS, REVSH 7339 and REV16 instructions. 7340 * A new vectorizer cost model for Advanced SIMD configurations to 7341 improve the auto-vectorization strategies used. 7342 * The scheduler now takes into account the number of live registers 7343 to reduce the amount of spilling that can occur. This should 7344 improve code performance in large functions. The limit can be 7345 removed by using the option -fno-sched-pressure. 7346 * Improvements have been made to the Marvell iWMMX code generation 7347 and support for the iWMMX2 SIMD unit has been added. The option 7348 -mcpu=iwmmxt2 can be used to enable code generation for the latter. 7349 * A number of code generation improvements for Thumb2 to reduce code 7350 size when compiling for the M-profile processors. 7351 * The RTEMS (arm-rtems) port has been updated to use the EABI. 7352 * Code generation support for the old FPA and Maverick floating-point 7353 architectures has been removed. Ports that previously relied on 7354 these features have also been removed. This includes the targets: 7355 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 7356 + arm*-*-elf (use arm*-*-eabi) 7357 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 7358 + arm*-*-ecos-elf (no alternative) 7359 + arm*-*-freebsd (no alternative) 7360 + arm*-wince-pe* (no alternative). 7361 7362 AVR 7363 7364 * Support for the "Embedded C" fixed-point has been added. For 7365 details, see the [28]GCC wiki and the [29]user manual. The support 7366 is not complete. 7367 * A new print modifier %r for register operands in inline assembler 7368 is supported. It will print the raw register number without the 7369 register prefix 'r': 7370 /* Return the most significant byte of 'val', a 64-bit value. */ 7371 7372 unsigned char msb (long long val) 7373 { 7374 unsigned char c; 7375 __asm__ ("mov %0, %r1+7" : "=r" (c) : "r" (val)); 7376 return c; 7377 } 7378 The inline assembler in this example will generate code like 7379 mov r24, 8+7 7380 provided c is allocated to R24 and val is allocated to R8R15. This 7381 works because the GNU assembler accepts plain register numbers 7382 without register prefix. 7383 * Static initializers with 3-byte symbols are supported now: 7384 extern const __memx char foo; 7385 const __memx void *pfoo = &foo; 7386 This requires at least Binutils 2.23. 7387 7388 IA-32/x86-64 7389 7390 * Allow -mpreferred-stack-boundary=3 for the x86-64 architecture with 7391 SSE extensions disabled. Since the x86-64 ABI requires 16 byte 7392 stack alignment, this is ABI incompatible and intended to be used 7393 in controlled environments where stack space is an important 7394 limitation. This option will lead to wrong code when functions 7395 compiled with 16 byte stack alignment (such as functions from a 7396 standard library) are called with misaligned stack. In this case, 7397 SSE instructions may lead to misaligned memory access traps. In 7398 addition, variable arguments will be handled incorrectly for 16 7399 byte aligned objects (including x87 long double and __int128), 7400 leading to wrong results. You must build all modules with 7401 -mpreferred-stack-boundary=3, including any libraries. This 7402 includes the system libraries and startup modules. 7403 * Support for the new Intel processor codename Broadwell with RDSEED, 7404 ADCX, ADOX, PREFETCHW is available through -madx, -mprfchw, 7405 -mrdseed command-line options. 7406 * Support for the Intel RTM and HLE intrinsics, built-in functions 7407 and code generation is available via -mrtm and -mhle. 7408 * Support for the Intel FXSR, XSAVE and XSAVEOPT instruction sets. 7409 Intrinsics and built-in functions are available via -mfxsr, -mxsave 7410 and -mxsaveopt respectively. 7411 * New -maddress-mode=[short|long] options for x32. 7412 -maddress-mode=short overrides default 64-bit addresses to 32-bit 7413 by emitting the 0x67 address-size override prefix. This is the 7414 default address mode for x32. 7415 * New built-in functions to detect run-time CPU type and ISA: 7416 + A built-in function __builtin_cpu_is has been added to detect 7417 if the run-time CPU is of a particular type. It returns a 7418 positive integer on a match and zero otherwise. It accepts one 7419 string literal argument, the CPU name. For example, 7420 __builtin_cpu_is("westmere") returns a positive integer if the 7421 run-time CPU is an Intel Core i7 Westmere processor. Please 7422 refer to the [30]user manual for the list of valid CPU names 7423 recognized. 7424 + A built-in function __builtin_cpu_supports has been added to 7425 detect if the run-time CPU supports a particular ISA feature. 7426 It returns a positive integer on a match and zero otherwise. 7427 It accepts one string literal argument, the ISA feature. For 7428 example, __builtin_cpu_supports("ssse3") returns a positive 7429 integer if the run-time CPU supports SSSE3 instructions. 7430 Please refer to the [31]user manual for the list of valid ISA 7431 names recognized. 7432 Caveat: If these built-in functions are called before any static 7433 constructors are invoked, like during IFUNC initialization, then 7434 the CPU detection initialization must be explicitly run using this 7435 newly provided built-in function, __builtin_cpu_init. The 7436 initialization needs to be done only once. For example, this is how 7437 the invocation would look like inside an IFUNC initializer: 7438 static void (*some_ifunc_resolver(void))(void) 7439 { 7440 __builtin_cpu_init(); 7441 if (__builtin_cpu_is("amdfam10h") ... 7442 if (__builtin_cpu_supports("popcnt") ... 7443 } 7444 7445 * Function Multiversioning Support with G++: 7446 It is now possible to create multiple function versions each 7447 targeting a specific processor and/or ISA. Function versions have 7448 the same signature but different target attributes. For example, 7449 here is a program with function versions: 7450 __attribute__ ((target ("default"))) 7451 int foo(void) 7452 { 7453 return 1; 7454 } 7455 7456 __attribute__ ((target ("sse4.2"))) 7457 int foo(void) 7458 { 7459 return 2; 7460 } 7461 7462 int main (void) 7463 { 7464 int (*p) = &foo; 7465 assert ((*p)() == foo()); 7466 return 0; 7467 } 7468 7469 Please refer to this [32]wiki for more information. 7470 * The x86 back end has been improved to allow option -fschedule-insns 7471 to work reliably. This option can be used to schedule instructions 7472 better and leads to improved performace in certain cases. 7473 * Windows MinGW-w64 targets (*-w64-mingw*) require at least r5437 7474 from the Mingw-w64 trunk. 7475 * Support for new AMD family 15h processors (Steamroller core) is now 7476 available through the -march=bdver3 and -mtune=bdver3 options. 7477 * Support for new AMD family 16h processors (Jaguar core) is now 7478 available through the -march=btver2 and -mtune=btver2 options. 7479 7480 FRV 7481 7482 * This target now supports the -fstack-usage command-line option. 7483 7484 MIPS 7485 7486 * GCC can now generate code specifically for the R4700, Broadcom XLP 7487 and MIPS 34kn processors. The associated -march options are 7488 -march=r4700, -march=xlp and -march=34kn respectively. 7489 * GCC now generates better DSP code for MIPS 74k cores thanks to 7490 further scheduling optimizations. 7491 * The MIPS port now supports the -fstack-check option. 7492 * GCC now passes the -mmcu and -mno-mcu options to the assembler. 7493 * Previous versions of GCC would silently accept -fpic and -fPIC for 7494 -mno-abicalls targets like mips*-elf. This combination was not 7495 intended or supported, and did not generate position-independent 7496 code. GCC 4.8 now reports an error when this combination is used. 7497 7498 PowerPC / PowerPC64 / RS6000 7499 7500 * SVR4 configurations (GNU/Linux, FreeBSD, NetBSD) no longer save, 7501 restore or update the VRSAVE register by default. The respective 7502 operating systems manage the VRSAVE register directly. 7503 * Large TOC support has been added for AIX through the command line 7504 option -mcmodel=large. 7505 * Native Thread-Local Storage support has been added for AIX. 7506 * VMX (Altivec) and VSX instruction sets now are enabled implicitly 7507 when targetting processors that support those hardware features on 7508 AIX 6.1 and above. 7509 7510 RX 7511 7512 * This target will now issue a warning message whenever multiple fast 7513 interrupt handlers are found in the same compilation unit. This 7514 feature can be turned off by the new 7515 -mno-warn-multiple-fast-interrupts command-line option. 7516 7517 S/390, System z 7518 7519 * Support for the IBM zEnterprise zEC12 processor has been added. 7520 When using the -march=zEC12 option, the compiler will generate code 7521 making use of the following new instructions: 7522 + load and trap instructions 7523 + 2 new compare and trap instructions 7524 + rotate and insert selected bits - without CC clobber 7525 The -mtune=zEC12 option enables zEC12 specific instruction 7526 scheduling without making use of new instructions. 7527 * Register pressure sensitive instruction scheduling is enabled by 7528 default. 7529 * The ifunc function attribute is enabled by default. 7530 * memcpy and memcmp invokations on big memory chunks or with run time 7531 lengths are not generated inline anymore when tuning for z10 or 7532 higher. The purpose is to make use of the IFUNC optimized versions 7533 in Glibc. 7534 7535 SH 7536 7537 * The default alignment settings have been reduced to be less 7538 aggressive. This results in more compact code for optimization 7539 levels other than -Os. 7540 * Improved support for the __atomic built-in functions: 7541 + A new option -matomic-model=model selects the model for the 7542 generated atomic sequences. The following models are 7543 supported: 7544 7545 soft-gusa 7546 Software gUSA sequences (SH3* and SH4* only). On 7547 SH4A targets this will now also partially utilize 7548 the movco.l and movli.l instructions. This is the 7549 default when the target is sh3*-*-linux* or 7550 sh4*-*-linux*. 7551 7552 hard-llcs 7553 Hardware movco.l / movli.l sequences (SH4A only). 7554 7555 soft-tcb 7556 Software thread control block sequences. 7557 7558 soft-imask 7559 Software interrupt flipping sequences (privileged 7560 mode only). This is the default when the target is 7561 sh1*-*-linux* or sh2*-*-linux*. 7562 7563 none 7564 Generates function calls to the respective __atomic 7565 built-in functions. This is the default for SH64 7566 targets or when the target is not sh*-*-linux*. 7567 7568 + The option -msoft-atomic has been deprecated. It is now an 7569 alias for -matomic-model=soft-gusa. 7570 + A new option -mtas makes the compiler generate the tas.b 7571 instruction for the __atomic_test_and_set built-in function 7572 regardless of the selected atomic model. 7573 + The __sync functions in libgcc now reflect the selected atomic 7574 model when building the toolchain. 7575 * Added support for the mov.b and mov.w instructions with 7576 displacement addressing. 7577 * Added support for the SH2A instructions movu.b and movu.w. 7578 * Various improvements to code generated for integer arithmetic. 7579 * Improvements to conditional branches and code that involves the T 7580 bit. A new option -mzdcbranch tells the compiler to favor 7581 zero-displacement branches. This is enabled by default for SH4* 7582 targets. 7583 * The pref instruction will now be emitted by the __builtin_prefetch 7584 built-in function for SH3* targets. 7585 * The fmac instruction will now be emitted by the fmaf standard 7586 function and the __builtin_fmaf built-in function. 7587 * The -mfused-madd option has been deprecated in favor of the 7588 machine-independent -ffp-contract option. Notice that the fmac 7589 instruction will now be generated by default for expressions like a 7590 * b + c. This is due to the compiler default setting 7591 -ffp-contract=fast. 7592 * Added new options -mfsrra and -mfsca to allow the compiler using 7593 the fsrra and fsca instructions on targets other than SH4A (where 7594 they are already enabled by default). 7595 * Added support for the __builtin_bswap32 built-in function. It is 7596 now expanded as a sequence of swap.b and swap.w instructions 7597 instead of a library function call. 7598 * The behavior of the -mieee option has been fixed and the negative 7599 form -mno-ieee has been added to control the IEEE conformance of 7600 floating point comparisons. By default -mieee is now enabled and 7601 the option -ffinite-math-only implicitly sets -mno-ieee. 7602 * Added support for the built-in functions __builtin_thread_pointer 7603 and __builtin_set_thread_pointer. This assumes that GBR is used to 7604 hold the thread pointer of the current thread. Memory loads and 7605 stores relative to the address returned by __builtin_thread_pointer 7606 will now also utilize GBR based displacement address modes. 7607 * The -mdiv= option for targets other than SHmedia has been fixed and 7608 documented. 7609 7610 SPARC 7611 7612 * Added optimized instruction scheduling for Niagara4. 7613 7614 TILE-Gx 7615 7616 * Added support for the -mcmodel=MODEL command-line option. The 7617 models supported are small and large. 7618 7619 V850 7620 7621 * This target now supports the E3V5 architecture via the use of the 7622 new -mv850e3v5 command-line option. It also has experimental 7623 support for the e3v5 LOOP instruction which can be enabled via the 7624 new -mloop command-line option. 7625 7626 XStormy16 7627 7628 * This target now supports the -fstack-usage command-line option. 7629 7630 Operating Systems 7631 7632 OpenBSD 7633 7634 * Support for OpenBSD/amd64 (x86_64-*-openbsd*) has been added and 7635 support for OpenBSD/i386 (i386-*-openbsd*) has been rejuvenated. 7636 7637 Windows (Cygwin) 7638 7639 * Executables are now linked against shared libgcc by default. The 7640 previous default was to link statically, which can still be done by 7641 explicitly specifying -static or static-libgcc on the command line. 7642 However it is strongly advised against, as it will cause problems 7643 for any application that makes use of DLLs compiled by GCC. It 7644 should be alright for a monolithic stand-alone application that 7645 only links against the Windows DLLs, but offers little or no 7646 benefit. 7647 7648 GCC 4.8.1 7649 7650 This is the [33]list of problem reports (PRs) from GCC's bug tracking 7651 system that are known to be fixed in the 4.8.1 release. This list might 7652 not be complete (that is, it is possible that some PRs that have been 7653 fixed are not listed here). 7654 7655 The C++11 <chrono> std::chrono::system_clock and 7656 std::chrono::steady_clock classes have changed ABI in GCC 4.8.1, they 7657 both are now separate (never typedefs of each other), both use 7658 std::chrono::nanoseconds resolution, on most GNU/Linux configurations 7659 std::chrono::steady_clock is now finally monotonic, and both classes 7660 are mangled differently than in the previous GCC releases. 7661 std::chrono::system_clock::now() with std::chrono::microseconds resp. 7662 std::chrono::seconds resolution is still exported for backwards 7663 compatibility with default configured libstdc++. Note that libstdc++ 7664 configured with --enable-libstdcxx-time= used to be ABI incompatible 7665 with default configured libstdc++ for those two classes and no ABI 7666 compatibility can be offered for those configurations, so any C++11 7667 code that uses those classes and has been compiled and linked against 7668 libstdc++ configured with the non-default --enable-libstdcxx-time= 7669 configuration option needs to be recompiled. 7670 7671 GCC 4.8.2 7672 7673 This is the [34]list of problem reports (PRs) from GCC's bug tracking 7674 system that are known to be fixed in the 4.8.2 release. This list might 7675 not be complete (that is, it is possible that some PRs that have been 7676 fixed are not listed here). 7677 7678 GCC 4.8.3 7679 7680 This is the [35]list of problem reports (PRs) from GCC's bug tracking 7681 system that are known to be fixed in the 4.8.3 release. This list might 7682 not be complete (that is, it is possible that some PRs that have been 7683 fixed are not listed here). 7684 7685 Support for the new powerpc64le-linux platform has been added. It 7686 defaults to generating code that conforms to the ELFV2 ABI. 7687 7688 GCC 4.8.4 7689 7690 This is the [36]list of problem reports (PRs) from GCC's bug tracking 7691 system that are known to be fixed in the 4.8.4 release. This list might 7692 not be complete (that is, it is possible that some PRs that have been 7693 fixed are not listed here). 7694 7695 GCC 4.8.5 7696 7697 This is the [37]list of problem reports (PRs) from GCC's bug tracking 7698 system that are known to be fixed in the 4.8.5 release. This list might 7699 not be complete (that is, it is possible that some PRs that have been 7700 fixed are not listed here). 7701 7702 7703 For questions related to the use of GCC, please consult these web 7704 pages and the [38]GCC manuals. If that fails, the 7705 [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 7706 web pages and the development of GCC are welcome on our developer 7707 list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public 7708 archives. 7709 7710 Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and 7711 distribution of this entire article is permitted in any medium, 7712 provided this notice is preserved. 7713 7714 These pages are [43]maintained by the GCC team. Last modified 7715 2021-07-28[44]. 7716 7717 References 7718 7719 1. https://gcc.gnu.org/wiki/cxx-conversion 7720 2. ftp://gcc.gnu.org/pub/gcc/infrastructure/ 7721 3. http://www.nongnu.org/avr-libc/ 7722 4. https://gcc.gnu.org/PR54461 7723 5. https://gcc.gnu.org/gcc-4.8/porting_to.html 7724 6. https://github.com/google/sanitizers 7725 7. https://code.google.com/archive/p/data-race-test/wikis/ThreadSanitizer.wiki 7726 8. https://lkml.org/lkml/2006/11/28/239 7727 9. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7728 10. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7729 11. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7730 12. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3276.pdf 7731 13. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7732 14. http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3386.html 7733 15. http://gcc.gnu.org/projects/cxx1y.html 7734 16. https://gcc.gnu.org/onlinedocs/gcc-4.8.4/libstdc++/manual/manual/status.html#status.iso.2011 7735 17. https://gcc.gnu.org/onlinedocs/gfortran/BACKTRACE.html 7736 18. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7737 19. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7738 20. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 7739 21. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7740 22. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7741 23. https://gcc.gnu.org/onlinedocs/gfortran/TMPDIR.html 7742 24. https://gcc.gnu.org/wiki/Fortran2003Status 7743 25. https://gcc.gnu.org/wiki/TS29113Status 7744 26. https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libgfortran/libgfortran.h 7745 27. http://chasm-interop.sourceforge.net/ 7746 28. https://gcc.gnu.org/wiki/avr-gcc#Fixed-Point_Support 7747 29. https://gcc.gnu.org/onlinedocs/gcc/Fixed-Point.html 7748 30. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 7749 31. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 7750 32. https://gcc.gnu.org/wiki/FunctionMultiVersioning 7751 33. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.1 7752 34. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.2 7753 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.3 7754 36. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.4 7755 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.5 7756 38. https://gcc.gnu.org/onlinedocs/ 7757 39. mailto:gcc-help (a] gcc.gnu.org 7758 40. mailto:gcc (a] gcc.gnu.org 7759 41. https://gcc.gnu.org/lists.html 7760 42. https://www.fsf.org/ 7761 43. https://gcc.gnu.org/about.html 7762 44. http://validator.w3.org/check/referer 7763 ====================================================================== 7764 http://gcc.gnu.org/gcc-4.7/index.html 7765 GCC 4.7 Release Series 7766 7767 (This release series is no longer supported.) 7768 7769 June 12, 2014 7770 7771 The [1]GNU project and the GCC developers are pleased to announce the 7772 release of GCC 4.7.4. 7773 7774 This release is a bug-fix release, containing fixes for regressions in 7775 GCC 4.7.3 relative to previous releases of GCC. 7776 7777 Release History 7778 7779 GCC 4.7.4 7780 June 12, 2014 ([2]changes, [3]documentation) 7781 7782 GCC 4.7.3 7783 April 11, 2013 ([4]changes, [5]documentation) 7784 7785 GCC 4.7.2 7786 September 20, 2012 ([6]changes, [7]documentation) 7787 7788 GCC 4.7.1 7789 June 14, 2012 ([8]changes, [9]documentation) 7790 7791 GCC 4.7.0 7792 March 22, 2012 ([10]changes, [11]documentation) 7793 7794 References and Acknowledgements 7795 7796 GCC used to stand for the GNU C Compiler, but since the compiler 7797 supports several other languages aside from C, it now stands for the 7798 GNU Compiler Collection. 7799 7800 A list of [12]successful builds is updated as new information becomes 7801 available. 7802 7803 The GCC developers would like to thank the numerous people that have 7804 contributed new features, improvements, bug fixes, and other changes as 7805 well as test results to GCC. This [13]amazing group of volunteers is 7806 what makes GCC successful. 7807 7808 For additional information about GCC please refer to the [14]GCC 7809 project web site or contact the [15]GCC development mailing list. 7810 7811 To obtain GCC please use [16]our mirror sites or [17]our version 7812 control system. 7813 7814 7815 For questions related to the use of GCC, please consult these web 7816 pages and the [18]GCC manuals. If that fails, the 7817 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 7818 web pages and the development of GCC are welcome on our developer 7819 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 7820 archives. 7821 7822 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 7823 distribution of this entire article is permitted in any medium, 7824 provided this notice is preserved. 7825 7826 These pages are [23]maintained by the GCC team. Last modified 7827 2021-07-28[24]. 7828 7829 References 7830 7831 1. http://www.gnu.org/ 7832 2. http://gcc.gnu.org/gcc-4.7/changes.html 7833 3. https://gcc.gnu.org/onlinedocs/4.7.4/ 7834 4. http://gcc.gnu.org/gcc-4.7/changes.html 7835 5. https://gcc.gnu.org/onlinedocs/4.7.3/ 7836 6. http://gcc.gnu.org/gcc-4.7/changes.html 7837 7. https://gcc.gnu.org/onlinedocs/4.7.2/ 7838 8. http://gcc.gnu.org/gcc-4.7/changes.html 7839 9. https://gcc.gnu.org/onlinedocs/4.7.1/ 7840 10. http://gcc.gnu.org/gcc-4.7/changes.html 7841 11. https://gcc.gnu.org/onlinedocs/4.7.0/ 7842 12. http://gcc.gnu.org/gcc-4.7/buildstat.html 7843 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 7844 14. http://gcc.gnu.org/index.html 7845 15. mailto:gcc (a] gcc.gnu.org 7846 16. http://gcc.gnu.org/mirrors.html 7847 17. http://gcc.gnu.org/git.html 7848 18. https://gcc.gnu.org/onlinedocs/ 7849 19. mailto:gcc-help (a] gcc.gnu.org 7850 20. mailto:gcc (a] gcc.gnu.org 7851 21. https://gcc.gnu.org/lists.html 7852 22. https://www.fsf.org/ 7853 23. https://gcc.gnu.org/about.html 7854 24. http://validator.w3.org/check/referer 7855 ====================================================================== 7856 http://gcc.gnu.org/gcc-4.7/changes.html 7857 GCC 4.7 Release Series 7858 Changes, New Features, and Fixes 7859 7860 Caveats 7861 7862 * The -fconserve-space flag has been deprecated. The flag had no 7863 effect for most targets: only targets without a global .bss section 7864 and without support for switchable sections. Furthermore, the flag 7865 only had an effect for G++, where it could result in wrong 7866 semantics (please refer to the GCC manual for further details). The 7867 flag will be removed in GCC 4.8 7868 * Support for a number of older systems and recently unmaintained or 7869 untested target ports of GCC has been declared obsolete in GCC 4.7. 7870 Unless there is activity to revive them, the next release of GCC 7871 will have their sources permanently removed. 7872 All GCC ports for the following processor architectures have been 7873 declared obsolete: 7874 + picoChip (picochip-*) 7875 The following ports for individual systems on particular 7876 architectures have been obsoleted: 7877 + IRIX 6.5 (mips-sgi-irix6.5) 7878 + MIPS OpenBSD (mips*-*-openbsd*) 7879 + Solaris 8 (*-*-solaris2.8). Details can be found in the 7880 [1]announcement. 7881 + Tru64 UNIX V5.1 (alpha*-dec-osf5.1*) 7882 * On ARM, when compiling for ARMv6 (but not ARMv6-M), ARMv7-A, 7883 ARMv7-R, or ARMv7-M, the new option -munaligned-access is active by 7884 default, which for some sources generates code that accesses memory 7885 on unaligned addresses. This requires the kernel of those systems 7886 to enable such accesses (controlled by CP15 register c1, refer to 7887 ARM documentation). Alternatively, or for compatibility with 7888 kernels where unaligned accesses are not supported, all code has to 7889 be compiled with -mno-unaligned-access. Upstream Linux kernel 7890 releases have automatically and unconditionally supported unaligned 7891 accesses as emitted by GCC due to this option being active since 7892 version 2.6.28. 7893 * Support on ARM for the legacy floating-point accelerator (FPA) and 7894 the mixed-endian floating-point format that it used has been 7895 obsoleted. The ports that still use this format have been obsoleted 7896 as well. Many legacy ARM ports already provide an alternative that 7897 uses the VFP floating-point format. The obsolete ports will be 7898 deleted in the next release. 7899 The obsolete ports with alternatives are: 7900 + arm*-*-rtems (use arm*-*-rtemseabi) 7901 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 7902 + arm*-*-elf (use arm*-*-eabi) 7903 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 7904 Note, however, that these alternatives are not binary compatible 7905 with their legacy counterparts (although some can support running 7906 legacy applications). 7907 The obsolete ports that currently lack a modern alternative are: 7908 + arm*-*-ecos-elf 7909 + arm*-*-freebsd 7910 + arm*-wince-pe* 7911 New ports that support more recent versions of the architecture are 7912 welcome. 7913 * Support for the Maverick co-processor on ARM has been obsoleted. 7914 Code to support it will be deleted in the next release. 7915 * Support has been removed for Unix International threads on Solaris 7916 2, so the --enable-threads=solaris configure option and the 7917 -threads compiler option don't work any longer. 7918 * Support has been removed for the Solaris BSD Compatibility Package, 7919 which lives in /usr/ucbinclude and /usr/ucblib. It has been removed 7920 from Solaris 11, and was only intended as a migration aid from 7921 SunOS 4 to SunOS 5. The -compat-bsd compiler option is not 7922 recognized any longer. 7923 * The AVR port's libgcc has been improved and its multilib structure 7924 has been enhanced. As a result, all objects contributing to an 7925 application must either be compiled with GCC versions up to 4.6.x 7926 or with GCC versions 4.7.1 or later. If the compiler is used with 7927 AVR Libc, you need a version that supports the new layout, i.e. 7928 implements [2]#35407. 7929 * The AVR port's -mshort-calls command-line option has been 7930 deprecated. It will be removed in the GCC 4.8 release. See -mrelax 7931 for a replacement. 7932 * The AVR port only references startup code that clears .bss and the 7933 common section resp. initializes the .data and .rodata section 7934 provided respective sections (or subsections thereof) are not 7935 empty, see [3]PR18145. Applications that put all static storage 7936 objects into non-standard sections and / or define all static 7937 storage objects in assembler modules, must reference __do_clear_bss 7938 resp. __do_copy_data by hand or undefine the symbol(s) by means of 7939 -Wl,-u,__do_clear_bss resp. -Wl,-u,__do_copy_data. 7940 * The ARM port's -mwords-little-endian option has been deprecated. It 7941 will be removed in a future release. 7942 * Support has been removed for the NetWare x86 configuration 7943 obsoleted in GCC 4.6. 7944 * It is no longer possible to use the "l" constraint in MIPS16 asm 7945 statements. 7946 * GCC versions 4.7.0 and 4.7.1 had changes to the C++ standard 7947 library which affected the ABI in C++11 mode: a data member was 7948 added to std::list changing its size and altering the definitions 7949 of some member functions, and std::pair's move constructor was 7950 non-trivial which altered the calling convention for functions with 7951 std::pair arguments or return types. The ABI incompatibilities have 7952 been fixed for GCC version 4.7.2 but as a result C++11 code 7953 compiled with GCC 4.7.0 or 4.7.1 may be incompatible with C++11 7954 code compiled with different GCC versions and with C++98/C++03 code 7955 compiled with any version. 7956 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 7957 rules for the layout of vectors that could lead to wrong code being 7958 generated. Vectors larger than 8 bytes in size are now by default 7959 aligned to an 8-byte boundary. This is an ABI change: code that 7960 makes explicit use of vector types may be incompatible with binary 7961 objects built with older versions of GCC. Auto-vectorized code is 7962 not affected by this change. (This change affects GCC versions 7963 4.7.2 and later.) 7964 * More information on porting to GCC 4.7 from previous versions of 7965 GCC can be found in the [4]porting guide for this release. 7966 7967 General Optimizer Improvements 7968 7969 * Support for a new parameter --param case-values-threshold=n was 7970 added to allow users to control the cutoff between doing switch 7971 statements as a series of if statements and using a jump table. 7972 * Link-time optimization (LTO) improvements: 7973 + Improved scalability and reduced memory usage. Link time 7974 optimization of Firefox now requires 3GB of RAM on a 64-bit 7975 system, while over 8GB was needed previously. Linking time has 7976 been improved, too. The serial stage of linking Firefox has 7977 been sped up by about a factor of 10. 7978 + Reduced size of object files and temporary storage used during 7979 linking. 7980 + Streaming performance (both outbound and inbound) has been 7981 improved. 7982 + ld -r is now supported with LTO. 7983 + Several bug fixes, especially in symbol table handling and 7984 merging. 7985 * Interprocedural optimization improvements: 7986 + Heuristics now take into account that after inlining code will 7987 be optimized out because of known values (or properties) of 7988 function parameters. For example: 7989 void foo(int a) 7990 { 7991 if (a > 10) 7992 ... huge code ... 7993 } 7994 void bar (void) 7995 { 7996 foo (0); 7997 } 7998 7999 The call of foo will be inlined into bar even when optimizing 8000 for code size. Constructs based on __builtin_constant_p are 8001 now understood by the inliner and code size estimates are 8002 evaluated a lot more realistically. 8003 + The representation of C++ virtual thunks and aliases (both 8004 implicit and defined via the alias attribute) has been 8005 re-engineered. Aliases no longer pose optimization barriers 8006 and calls to an alias can be inlined and otherwise optimized. 8007 + The inter-procedural constant propagation pass has been 8008 rewritten. It now performs generic function specialization. 8009 For example when compiling the following: 8010 void foo(bool flag) 8011 { 8012 if (flag) 8013 ... do something ... 8014 else 8015 ... do something else ... 8016 } 8017 void bar (void) 8018 { 8019 foo (false); 8020 foo (true); 8021 foo (false); 8022 foo (true); 8023 foo (false); 8024 foo (true); 8025 } 8026 8027 GCC will now produce two copies of foo. One with flag being 8028 true, while other with flag being false. This leads to 8029 performance improvements previously possible only by inlining 8030 all calls. Cloning causes a lot less code size growth. 8031 * A string length optimization pass has been added. It attempts to 8032 track string lengths and optimize various standard C string 8033 functions like strlen, strchr, strcpy, strcat, stpcpy and their 8034 _FORTIFY_SOURCE counterparts into faster alternatives. This pass is 8035 enabled by default at -O2 or above, unless optimizing for size, and 8036 can be disabled by the -fno-optimize-strlen option. The pass can 8037 e.g. optimize 8038 char *bar (const char *a) 8039 { 8040 size_t l = strlen (a) + 2; 8041 char *p = malloc (l); if (p == NULL) return p; 8042 strcpy (p, a); strcat (p, "/"); return p; 8043 } 8044 8045 into: 8046 char *bar (const char *a) 8047 { 8048 size_t tmp = strlen (a); 8049 char *p = malloc (tmp + 2); if (p == NULL) return p; 8050 memcpy (p, a, tmp); memcpy (p + tmp, "/", 2); return p; 8051 } 8052 8053 or for hosted compilations where stpcpy is available in the runtime 8054 and headers provide its prototype, e.g. 8055 void foo (char *a, const char *b, const char *c, const char *d) 8056 { 8057 strcpy (a, b); strcat (a, c); strcat (a, d); 8058 } 8059 8060 can be optimized into: 8061 void foo (char *a, const char *b, const char *c, const char *d) 8062 { 8063 strcpy (stpcpy (stpcpy (a, b), c), d); 8064 } 8065 8066 New Languages and Language specific improvements 8067 8068 * Version 3.1 of the OpenMP specification is now supported for the C, 8069 C++, and Fortran compilers. 8070 8071 Ada 8072 8073 * The command-line option -feliminate-unused-debug-types has been 8074 re-enabled by default, as it is for the other languages, leading to 8075 a reduction in debug info size of 12.5% and more for relevant 8076 cases, as well as to a small compilation speedup. 8077 8078 C family 8079 8080 * A new built-in, __builtin_assume_aligned, has been added, through 8081 which the compiler can be hinted about pointer alignment and can 8082 use it to improve generated code. 8083 * A new warning option -Wunused-local-typedefs was added for C, C++, 8084 Objective-C and Objective-C++. This warning diagnoses typedefs 8085 locally defined in a function, and otherwise not used. 8086 * A new experimental command-line option -ftrack-macro-expansion was 8087 added for C, C++, Objective-C, Objective-C++ and Fortran. It allows 8088 the compiler to emit diagnostic about the current macro expansion 8089 stack when a compilation error occurs in a macro expansion. 8090 * Experimental support for transactional memory has been added. It 8091 includes support in the compiler, as well as a supporting runtime 8092 library called libitm. To compile code with transactional memory 8093 constructs, use the -fgnu-tm option. 8094 Support is currently available for Alpha, ARM, PowerPC, SH, SPARC, 8095 and 32-bit/64-bit x86 platforms. 8096 For more details on transactional memory see [5]the GCC WiKi. 8097 * Support for atomic operations specifying the C++11/C11 memory model 8098 has been added. These new __atomic routines replace the existing 8099 __sync built-in routines. 8100 Atomic support is also available for memory blocks. Lock-free 8101 instructions will be used if a memory block is the same size and 8102 alignment as a supported integer type. Atomic operations which do 8103 not have lock-free support are left as function calls. A set of 8104 library functions is available on the GCC atomic wiki in the 8105 "External Atomics Library" section. 8106 For more details on the memory models and features, see the 8107 [6]atomic wiki. 8108 * When a binary operation is performed on vector types and one of the 8109 operands is a uniform vector, it is possible to replace the vector 8110 with the generating element. For example: 8111 typedef int v4si __attribute__ ((vector_size (16))); 8112 v4si res, a = {1,2,3,4}; 8113 int x; 8114 8115 res = 2 + a; /* means {2,2,2,2} + a */ 8116 res = a - x; /* means a - {x,x,x,x} */ 8117 8118 C 8119 8120 * There is support for some more features from the C11 revision of 8121 the ISO C standard. GCC now accepts the options -std=c11 and 8122 -std=gnu11, in addition to the previous -std=c1x and -std=gnu1x. 8123 + Unicode strings (previously supported only with options such 8124 as -std=gnu11, now supported with -std=c11), and the 8125 predefined macros __STDC_UTF_16__ and __STDC_UTF_32__. 8126 + Nonreturning functions (_Noreturn and <stdnoreturn.h>). 8127 + Alignment support (_Alignas, _Alignof, max_align_t, 8128 <stdalign.h>). 8129 + A built-in function __builtin_complex is provided to support C 8130 library implementation of the CMPLX family of macros. 8131 8132 C++ 8133 8134 * G++ now accepts the -std=c++11, -std=gnu++11, and -Wc++11-compat 8135 options, which are equivalent to -std=c++0x, -std=gnu++0x, and 8136 -Wc++0x-compat, respectively. 8137 * G++ now implements [7]C++11 extended friend syntax: 8138 8139 template<class W> 8140 class Q 8141 { 8142 static const int I = 2; 8143 public: 8144 friend W; 8145 }; 8146 8147 struct B 8148 { 8149 int ar[Q<B>::I]; 8150 }; 8151 8152 * Thanks to Ville Voutilainen, G++ now implements [8]C++11 explicit 8153 override control. 8154 8155 struct B { 8156 virtual void f() const final; 8157 virtual void f(int); 8158 }; 8159 8160 struct D : B { 8161 void f() const; // error: D::f attempts to override final B::f 8162 void f(long) override; // error: doesn't override anything 8163 void f(int) override; // ok 8164 }; 8165 8166 struct E final { }; 8167 struct F: E { }; // error: deriving from final class 8168 8169 * G++ now implements [9]C++11 non-static data member initializers. 8170 8171 struct A { 8172 int i = 42; 8173 } a; // initializes a.i to 42 8174 8175 * Thanks to Ed Smith-Rowland, G++ now implements [10]C++11 8176 user-defined literals. 8177 8178 // Not actually a good approximation. :) 8179 constexpr long double operator"" _degrees (long double d) { return d * 0.0175; } 8180 long double pi = 180.0_degrees; 8181 8182 * G++ now implements [11]C++11 alias-declarations. 8183 8184 template <class T> using Ptr = T*; 8185 Ptr<int> ip; // decltype(ip) is int* 8186 8187 * Thanks to Ville Voutilainen and Pedro Lamaro, G++ now implements 8188 [12]C++11 delegating constructors. 8189 8190 struct A { 8191 A(int); 8192 A(): A(42) { } // delegate to the A(int) constructor 8193 }; 8194 8195 * G++ now fully implements C++11 atomic classes rather than just 8196 integer derived classes. 8197 8198 class POD { 8199 int a; 8200 int b; 8201 }; 8202 std::atomic<POD> my_atomic_POD; 8203 8204 * G++ now sets the predefined macro __cplusplus to the correct value, 8205 199711L for C++98/03, and 201103L for C++11. 8206 * G++ now correctly implements the two-phase lookup rules such that 8207 an unqualified name used in a template must have an appropriate 8208 declaration found either in scope at the point of definition of the 8209 template or by argument-dependent lookup at the point of 8210 instantiation. As a result, code that relies on a second 8211 unqualified lookup at the point of instantiation to find functions 8212 declared after the template or in dependent bases will be rejected. 8213 The compiler will suggest ways to fix affected code, and using the 8214 -fpermissive compiler flag will allow the code to compile with a 8215 warning. 8216 8217 template <class T> 8218 void f() { g(T()); } // error, g(int) not found by argument-dependent lookup 8219 void g(int) { } // fix by moving this declaration before the declaration of f 8220 8221 template <class T> 8222 struct A: T { 8223 // error, B::g(B) not found by argument-dependent lookup 8224 void f() { g(T()); } // fix by using this->g or A::g 8225 }; 8226 8227 struct B { void g(B); }; 8228 8229 int main() 8230 { 8231 f<int>(); 8232 A<B>().f(); 8233 } 8234 8235 * G++ now properly re-uses stack space allocated for temporary 8236 objects when their lifetime ends, which can significantly lower 8237 stack consumption for some C++ functions. As a result of this, some 8238 code with undefined behavior will now break: 8239 8240 const int &f(const int &i) { return i; } 8241 .... 8242 const int &x = f(1); 8243 const int &y = f(2); 8244 8245 Here, x refers to the temporary allocated to hold the 1 argument, 8246 which only lives until the end of the initialization; it 8247 immediately becomes a dangling reference. So the next statement 8248 re-uses the stack slot to hold the 2 argument, and users of x get 8249 that value instead. 8250 Note that this should not cause any change of behavior for 8251 temporaries of types with non-trivial destructors, as they are 8252 already destroyed at end of full-expression; the change is that now 8253 the storage is released as well. 8254 * A new command-line option -Wdelete-non-virtual-dtor has been added 8255 to warn when delete is used to destroy an instance of a class which 8256 has virtual functions and non-virtual destructor. It is unsafe to 8257 delete an instance of a derived class through a pointer to a base 8258 class if the base class does not have a virtual destructor. This 8259 warning is enabled by -Wall. 8260 * A new command-line option -Wzero-as-null-pointer-constant has been 8261 added to warn when a literal '0' is used as null pointer constant. 8262 It can be useful to facilitate the conversion to nullptr in C++11. 8263 * As per C++98, access-declarations are now deprecated by G++. 8264 Using-declarations are to be used instead. Furthermore, some 8265 efforts have been made to improve the support of class scope 8266 using-declarations. In particular, using-declarations referring to 8267 a dependent type now work as expected ([13]bug c++/14258). 8268 * The ELF symbol visibility of a template instantiation is now 8269 properly constrained by the visibility of its template arguments 8270 ([14]bug c++/35688). 8271 8272 Runtime Library (libstdc++) 8273 8274 * [15]Improved experimental support for the new ISO C++ standard, 8275 C++11, including: 8276 + using noexcept in most of the library; 8277 + implementations of pointer_traits, allocator_traits and 8278 scoped_allocator_adaptor; 8279 + uses-allocator construction for tuple; 8280 + vector meets the allocator-aware container requirements; 8281 + replacing monotonic_clock with steady_clock; 8282 + enabling the thread support library on most POSIX targets; 8283 + many small improvements to conform to the FDIS. 8284 * Added --enable-clocale=newlib configure option. 8285 * Debug Mode iterators for unordered associative containers. 8286 * Avoid polluting the global namespace and do not include <unistd.h>. 8287 8288 Fortran 8289 8290 * The compile flag [16]-fstack-arrays has been added, which causes 8291 all local arrays to be put on stack memory. For some programs this 8292 will improve the performance significantly. If your program uses 8293 very large local arrays, it is possible that you will have to 8294 extend your runtime limits for stack memory. 8295 * The [17]-Ofast flag now also implies [18]-fno-protect-parens and 8296 [19]-fstack-arrays. 8297 * Front-end optimizations can now be selected by the 8298 [20]-ffrontend-optimize option and deselected by the 8299 -fno-frontend-optimize option. 8300 * When front-end optimization removes a function call, 8301 [21]-Wfunction-elimination warns about that. 8302 * When performing front-end-optimization, the 8303 [22]-faggressive-function-elimination option allows the removal of 8304 duplicate function calls even for impure functions. 8305 * The flag [23]-Wreal-q-constant has been added, which warns if 8306 floating-point literals have been specified using q (such as 8307 1.0q0); the q marker is now supported as a vendor extension to 8308 denote quad precision (REAL(16) or, if not available, REAL(10)). 8309 Consider using a kind parameter (such as in 1.0_qp) instead, which 8310 can be obtained via [24]SELECTED_REAL_KIND. 8311 * The GFORTRAN_USE_STDERR environment variable has been removed. GNU 8312 Fortran now always prints error messages to standard error. If you 8313 wish to redirect standard error, please consult the manual for your 8314 OS, shell, batch environment etc. as appropriate. 8315 * The -fdump-core option and GFORTRAN_ERROR_DUMPCORE environment 8316 variable have been removed. When encountering a serious error, 8317 gfortran will now always abort the program. Whether a core dump is 8318 generated depends on the user environment settings; see the ulimit 8319 -c setting for POSIX shells, limit coredumpsize for C shells, and 8320 the [25]WER user-mode dumps settings on Windows. 8321 * The [26]-fbacktrace option is now enabled by default. When 8322 encountering a fatal error, gfortran will attempt to print a 8323 backtrace to standard error before aborting. It can be disabled 8324 with -fno-backtrace. Note: On POSIX targets with the addr2line 8325 utility from GNU binutils, GNU Fortran can print a backtrace with 8326 function name, file name, line number information in addition to 8327 the addresses; otherwise only the addresses are printed. 8328 * [27]Fortran 2003: 8329 + Generic interface names which have the same name as derived 8330 types are now supported, which allows to write constructor 8331 functions. Note that Fortran does not support static 8332 constructor functions; only default initialization or an 8333 explicit structure-constructor initialization are available. 8334 + [28]Polymorphic (class) arrays are now supported. 8335 * [29]Fortran 2008: 8336 + Support for the DO CONCURRENT construct has been added, which 8337 allows the user to specify that individual loop iterations 8338 have no interdependencies. 8339 + [30]Coarrays: Full single-image support except for polymorphic 8340 coarrays. Additionally, preliminary support for multiple 8341 images via an MPI-based [31]coarray communication library has 8342 been added. Note: The library version is not yet usable as 8343 remote coarray access is not yet possible. 8344 * [32]TS 29113: 8345 + New flag [33]-std=f2008ts permits programs that are expected 8346 to conform to the Fortran 2008 standard and the draft 8347 Technical Specification (TS) 29113 on Further Interoperability 8348 of Fortran with C. 8349 + The OPTIONAL attribute is now allowed for dummy arguments of 8350 BIND(C) procedures. 8351 + The RANK intrinsic has been added. 8352 + The implementation of the ASYNCHRONOUS attribute in GCC is 8353 compatible with the candidate draft of TS 29113 (since GCC 8354 4.6). 8355 8356 Go 8357 8358 * GCC 4.7 implements the [34]Go 1 language standard. The library 8359 support in 4.7.0 is not quite complete, due to release timing. 8360 Release 4.7.1 includes complete support for Go 1. The Go library is 8361 from the Go 1.0.1 release. 8362 * Go has been tested on GNU/Linux and Solaris platforms. It may work 8363 on other platforms as well. 8364 8365 New Targets and Target Specific Improvements 8366 8367 ARM 8368 8369 * GCC now supports the Cortex-A7 processor implementing the v7-a 8370 version of the architecture using the option -mcpu=cortex-a7. 8371 * The default vector size in auto-vectorization for NEON is now 128 8372 bits. If vectorization fails thusly, the vectorizer tries again 8373 with 64-bit vectors. 8374 * A new option -mvectorize-with-neon-double was added to allow users 8375 to change the vector size to 64 bits. 8376 8377 AVR 8378 8379 * GCC now supports the XMEGA architecture. This requires GNU binutils 8380 2.22 or later. 8381 * Support for the [35]named address spaces __flash, __flash1, , 8382 __flash5 and __memx has been added. These address spaces locate 8383 read-only data in flash memory and allow reading from flash memory 8384 by means of ordinary C code, i.e. without the need of (inline) 8385 assembler code: 8386 8387 const __flash int values[] = { 42, 31 }; 8388 8389 int add_values (const __flash int *p, int i) 8390 { 8391 return values[i] + *p; 8392 } 8393 8394 * Support has been added for the AVR-specific configure option 8395 --with-avrlibc=yes in order to arrange for better integration of 8396 [36]AVR-Libc. This configure option is supported in avr-gcc 4.7.2 8397 and newer and will only take effect in non-RTEMS configurations. If 8398 avr-gcc is configured for RTEMS, the option will be ignored which 8399 is the same as specifying --with-avrlibc=no. See [37]PR54461 for 8400 more technical details. 8401 * Support for AVR-specific [38]built-in functions has been added. 8402 * Support has been added for the signed and unsigned 24-bit scalar 8403 integer types __int24 and __uint24. 8404 * New command-line options -maccumulate-args, -mbranch-cost=cost and 8405 -mstrict-X were added to allow better fine-tuning of code 8406 optimization. 8407 * The command-line option -fdata-sections now also takes affect on 8408 the section names of variables with the progmem attribute. 8409 * A new inline assembler print modifier %i to print a RAM address as 8410 I/O address has been added: 8411 8412 #include <avr/io.h> /* Port Definitions from AVR-LibC */ 8413 8414 void set_portb (uint8_t value) 8415 { 8416 asm volatile ("out %i0, %1" :: "n" (&PORTB), "r" (value) : "memory"); 8417 } 8418 8419 The offset between an I/O address and the RAM address for that I/O 8420 location is device-specific. This offset is taken into account when 8421 printing a RAM address with the %i modifier so that the address is 8422 suitable to be used as operand in an I/O command. The address must 8423 be a constant integer known at compile time. 8424 * The inline assembler constraint "R" to represent integers in the 8425 range 6 5 has been removed without replacement. 8426 * Many optimizations to: 8427 + 64-bit integer arithmetic 8428 + Widening multiplication 8429 + Integer division by a constant 8430 + Avoid constant reloading in multi-byte instructions. 8431 + Micro-optimizations for special instruction sequences. 8432 + Generic built-in functions like __builtin_ffs*, 8433 __builtin_clz*, etc. 8434 + If-else decision trees generated by switch instructions 8435 + Merging of data located in flash memory 8436 + New libgcc variants for devices with 8-bit wide stack pointer 8437 + 8438 * Better documentation: 8439 + Handling of EIND and indirect jumps on devices with more than 8440 128 KiB of program memory. 8441 + Handling of the RAMPD, RAMPX, RAMPY and RAMPZ special function 8442 registers. 8443 + Function attributes OS_main and OS_task. 8444 + AVR-specific built-in macros. 8445 8446 C6X 8447 8448 * Support has been added for the Texas Instruments C6X family of 8449 processors. 8450 8451 CR16 8452 8453 * Support has been added for National Semiconductor's CR16 8454 architecture. 8455 8456 Epiphany 8457 8458 * Support has been added for Adapteva's Epiphany architecture. 8459 8460 IA-32/x86-64 8461 8462 * Support for Intel AVX2 intrinsics, built-in functions and code 8463 generation is available via -mavx2. 8464 * Support for Intel BMI2 intrinsics, built-in functions and code 8465 generation is available via -mbmi2. 8466 * Implementation and automatic generation of __builtin_clz* using the 8467 lzcnt instruction is available via -mlzcnt. 8468 * Support for Intel FMA3 intrinsics and code generation is available 8469 via -mfma. 8470 * A new -mfsgsbase command-line option is available that makes GCC 8471 generate new segment register read/write instructions through 8472 dedicated built-ins. 8473 * Support for the new Intel rdrnd instruction is available via 8474 -mrdrnd. 8475 * Two additional AVX vector conversion instructions are available via 8476 -mf16c. 8477 * Support for new Intel processor codename IvyBridge with RDRND, 8478 FSGSBASE and F16C is available through -march=core-avx-i. 8479 * Support for the new Intel processor codename Haswell with AVX2, 8480 FMA, BMI, BMI2, LZCNT is available through -march=core-avx2. 8481 * Support for new AMD family 15h processors (Piledriver core) is now 8482 available through -march=bdver2 and -mtune=bdver2 options. 8483 * Support for [39]the x32 psABI is now available through the -mx32 8484 option. 8485 * Windows mingw targets are using the -mms-bitfields option by 8486 default. 8487 * Windows x86 targets are using the __thiscall calling convention for 8488 C++ class-member functions. 8489 * Support for the configure option --with-threads=posix for Windows 8490 mingw targets. 8491 8492 MIPS 8493 8494 * GCC now supports thread-local storage (TLS) for MIPS16. This 8495 requires GNU binutils 2.22 or later. 8496 * GCC can now generate code specifically for the Cavium Octeon+ and 8497 Octeon2 processors. The associated command-line options are 8498 -march=octeon+ and -march=octeon2 respectively. Both options 8499 require GNU binutils 2.22 or later. 8500 * GCC can now work around certain 24k errata, under the control of 8501 the command-line option -mfix-24k. These workarounds require GNU 8502 binutils 2.20 or later. 8503 * 32-bit MIPS GNU/Linux targets such as mips-linux-gnu can now build 8504 n32 and n64 multilibs. The result is effectively a 64-bit GNU/Linux 8505 toolchain that generates 32-bit code by default. Use the 8506 configure-time option --enable-targets=all to select these extra 8507 multilibs. 8508 * Passing -fno-delayed-branch now also stops the assembler from 8509 automatically filling delay slots. 8510 8511 PowerPC/PowerPC64 8512 8513 * Vectors of type vector long long or vector long are passed and 8514 returned using the same method as other vectors with the VSX 8515 instruction set. Previously GCC did not adhere to the ABI for 8516 128-bit vectors with 64-bit integer base types (PR 48857). This 8517 will also be fixed in the GCC 4.6.1 and 4.5.4 releases. 8518 * A new option -mno-pointers-to-nested-functions was added to allow 8519 AIX 32-bit/64-bit and GNU/Linux 64-bit PowerPC users to specify 8520 that the compiler should not load up the chain register (r11) 8521 before calling a function through a pointer. If you use this 8522 option, you cannot call nested functions through a pointer, or call 8523 other languages that might use the static chain. 8524 * A new option msave-toc-indirect was added to allow AIX 8525 32-bit/64-bit and GNU/Linux 64-bit PowerPC users control whether we 8526 save the TOC in the prologue for indirect calls or generate the 8527 save inline. This can speed up some programs that call through a 8528 function pointer a lot, but it can slow down other functions that 8529 only call through a function pointer in exceptional cases. 8530 * The PowerPC port will now enable machine-specific built-in 8531 functions when the user switches the target machine using the 8532 #pragma GCC target or __attribute__ ((__target__ ("target"))) code 8533 sequences. In addition, the target macros are updated. However, due 8534 to the way the -save-temps switch is implemented, you won't see the 8535 effect of these additional macros being defined in preprocessor 8536 output. 8537 8538 SH 8539 8540 * A new option -msoft-atomic has been added. When it is specified, 8541 GCC will generate GNU/Linux-compatible gUSA atomic sequences for 8542 the new __atomic routines. 8543 * Since it is neither supported by GAS nor officially documented, 8544 code generation for little endian SH2A has been disabled. 8545 Specifying -ml with -m2a* will now result in a compiler error. 8546 * The defunct -mbranch-cost option has been fixed. 8547 * Some improvements to the generated code of: 8548 + Utilization of the tst #imm,R0 instruction. 8549 + Dynamic shift instructions on SH2A. 8550 + Integer absolute value calculations. 8551 * The -mdiv= option for targets other than SHmedia has been fixed and 8552 documented. 8553 8554 SPARC 8555 8556 * The option -mflat has been reinstated. When it is specified, the 8557 compiler will generate code for a single register window model. 8558 This is essentially a new implementation and the corresponding 8559 debugger support has been added to GDB 7.4. 8560 * Support for the options -mtune=native and -mcpu=native has been 8561 added on selected native platforms (GNU/Linux and Solaris). 8562 * Support for the SPARC T3 (Niagara 3) processor has been added. 8563 * VIS: 8564 + An intrinsics header visintrin.h has been added. 8565 + Builtin intrinsics for the VIS 1.0 edge handling and pixel 8566 compare instructions have been added. 8567 + The little-endian version of alignaddr is now supported. 8568 + When possible, VIS builtins are marked const, which should 8569 increase the compiler's ability to optimize VIS operations. 8570 + The compiler now properly tracks the %gsr register and how it 8571 behaves as an input for various VIS instructions. 8572 + Akin to fzero, the compiler can now generate fone instructions 8573 in order to set all of the bits of a floating-point register 8574 to 1. 8575 + The documentation for the VIS intrinsics in the GCC manual has 8576 been brought up to date and many inaccuracies were fixed. 8577 + Intrinsics for the VIS 2.0 bmask, bshuffle, and 8578 non-condition-code setting edge instructions have been added. 8579 Their availability is controlled by the new -mvis2 and 8580 -mno-vis2 options. They are enabled by default on 8581 UltraSPARC-III and later CPUs. 8582 * Support for UltraSPARC Fused Multiply-Add floating-point extensions 8583 has been added. These instructions are enabled by default on SPARC 8584 T3 (Niagara 3) and later CPUs. 8585 8586 TILE-Gx/TILEPro 8587 8588 * Support has been added for the Tilera TILE-Gx and TILEPro families 8589 of processors. 8590 8591 Other significant improvements 8592 8593 * A new option (-grecord-gcc-switches) was added that appends 8594 compiler command-line options that might affect code generation to 8595 the DW_AT_producer attribute string in the DWARF debugging 8596 information. 8597 * GCC now supports various new GNU extensions to the DWARF debugging 8598 information format, like [40]entry value and [41]call site 8599 information, [42]typed DWARF stack or [43]a more compact macro 8600 representation. Support for these extensions has been added to GDB 8601 7.4. They can be disabled through the -gstrict-dwarf command-line 8602 option. 8603 8604 GCC 4.7.1 8605 8606 This is the [44]list of problem reports (PRs) from GCC's bug tracking 8607 system that are known to be fixed in the 4.7.1 release. This list might 8608 not be complete (that is, it is possible that some PRs that have been 8609 fixed are not listed here). 8610 8611 The Go front end in the 4.7.1 release fully supports the [45]Go 1 8612 language standard. 8613 8614 GCC 4.7.2 8615 8616 This is the [46]list of problem reports (PRs) from GCC's bug tracking 8617 system that are known to be fixed in the 4.7.2 release. This list might 8618 not be complete (that is, it is possible that some PRs that have been 8619 fixed are not listed here). 8620 8621 GCC 4.7.3 8622 8623 This is the [47]list of problem reports (PRs) from GCC's bug tracking 8624 system that are known to be fixed in the 4.7.3 release. This list might 8625 not be complete (that is, it is possible that some PRs that have been 8626 fixed are not listed here). 8627 8628 GCC 4.7.4 8629 8630 This is the [48]list of problem reports (PRs) from GCC's bug tracking 8631 system that are known to be fixed in the 4.7.4 release. This list might 8632 not be complete (that is, it is possible that some PRs that have been 8633 fixed are not listed here). 8634 8635 8636 For questions related to the use of GCC, please consult these web 8637 pages and the [49]GCC manuals. If that fails, the 8638 [50]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8639 web pages and the development of GCC are welcome on our developer 8640 list at [51]gcc (a] gcc.gnu.org. All of [52]our lists have public 8641 archives. 8642 8643 Copyright (C) [53]Free Software Foundation, Inc. Verbatim copying and 8644 distribution of this entire article is permitted in any medium, 8645 provided this notice is preserved. 8646 8647 These pages are [54]maintained by the GCC team. Last modified 8648 2022-02-10[55]. 8649 8650 References 8651 8652 1. https://gcc.gnu.org/ml/gcc-patches/2011-03/msg01263.html 8653 2. http://savannah.nongnu.org/bugs/?35407 8654 3. https://gcc.gnu.org/PR18145 8655 4. https://gcc.gnu.org/gcc-4.7/porting_to.html 8656 5. https://gcc.gnu.org/wiki/TransactionalMemory 8657 6. https://gcc.gnu.org/wiki/Atomic/GCCMM 8658 7. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8659 8. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8660 9. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8661 10. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8662 11. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8663 12. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8664 13. https://gcc.gnu.org/PR14258 8665 14. https://gcc.gnu.org/PR35688 8666 15. https://gcc.gnu.org/onlinedocs/gcc-4.7.4/libstdc++/manual/manual/status.html#status.iso.2011 8667 16. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 8668 17. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Optimize-Options.html#index-Ofast-689 8669 18. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfno-protect-parens_007d-270 8670 19. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 8671 20. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfrontend-optimize_007d-275 8672 21. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWfunction-elimination_007d-170 8673 22. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfaggressive-function-elimination_007d-270 8674 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 8675 24. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/SELECTED_005fREAL_005fKIND.html 8676 25. https://docs.microsoft.com/en-us/windows/win32/wer/collecting-user-mode-dumps 8677 26. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Debugging-Options.html#index-g_t_0040code_007bfno-backtrace_007d-183 8678 27. https://gcc.gnu.org/wiki/Fortran2003Status 8679 28. https://gcc.gnu.org/wiki/OOP 8680 29. https://gcc.gnu.org/wiki/Fortran2008Status 8681 30. https://gcc.gnu.org/wiki/Coarray 8682 31. https://gcc.gnu.org/wiki/CoarrayLib 8683 32. https://gcc.gnu.org/wiki/TS29113Status 8684 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 8685 34. https://go.dev/doc/go1 8686 35. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Named-Address-Spaces.html 8687 36. http://www.nongnu.org/avr-libc/ 8688 37. https://gcc.gnu.org/PR54461 8689 38. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/AVR-Built_002din-Functions.html 8690 39. https://sites.google.com/site/x32abi/ 8691 40. https://www.dwarfstd.org/ShowIssue.php?issue=100909.1 8692 41. https://www.dwarfstd.org/ShowIssue.php?issue=100909.2 8693 42. https://www.dwarfstd.org/ShowIssue.php?issue=140425.1 8694 43. https://www.dwarfstd.org/ShowIssue.php?issue=110722.1 8695 44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.1 8696 45. https://go.dev/doc/go1 8697 46. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.2 8698 47. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.3 8699 48. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.4 8700 49. https://gcc.gnu.org/onlinedocs/ 8701 50. mailto:gcc-help (a] gcc.gnu.org 8702 51. mailto:gcc (a] gcc.gnu.org 8703 52. https://gcc.gnu.org/lists.html 8704 53. https://www.fsf.org/ 8705 54. https://gcc.gnu.org/about.html 8706 55. http://validator.w3.org/check/referer 8707 ====================================================================== 8708 http://gcc.gnu.org/gcc-4.6/index.html 8709 GCC 4.6 Release Series 8710 8711 (This release series is no longer supported.) 8712 8713 April 12, 2013 8714 8715 The [1]GNU project and the GCC developers are pleased to announce the 8716 release of GCC 4.6.4. 8717 8718 This release is a bug-fix release, containing fixes for regressions in 8719 GCC 4.6.3 relative to previous releases of GCC. 8720 8721 Release History 8722 8723 GCC 4.6.4 8724 April 12, 2013 ([2]changes, [3]documentation) 8725 8726 GCC 4.6.3 8727 March 1, 2012 ([4]changes, [5]documentation) 8728 8729 GCC 4.6.2 8730 October 26, 2011 ([6]changes, [7]documentation) 8731 8732 GCC 4.6.1 8733 June 27, 2011 ([8]changes, [9]documentation) 8734 8735 GCC 4.6.0 8736 March 25, 2011 ([10]changes, [11]documentation) 8737 8738 References and Acknowledgements 8739 8740 GCC used to stand for the GNU C Compiler, but since the compiler 8741 supports several other languages aside from C, it now stands for the 8742 GNU Compiler Collection. 8743 8744 A list of [12]successful builds is updated as new information becomes 8745 available. 8746 8747 The GCC developers would like to thank the numerous people that have 8748 contributed new features, improvements, bug fixes, and other changes as 8749 well as test results to GCC. This [13]amazing group of volunteers is 8750 what makes GCC successful. 8751 8752 For additional information about GCC please refer to the [14]GCC 8753 project web site or contact the [15]GCC development mailing list. 8754 8755 To obtain GCC please use [16]our mirror sites or [17]our version 8756 control system. 8757 8758 8759 For questions related to the use of GCC, please consult these web 8760 pages and the [18]GCC manuals. If that fails, the 8761 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8762 web pages and the development of GCC are welcome on our developer 8763 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 8764 archives. 8765 8766 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 8767 distribution of this entire article is permitted in any medium, 8768 provided this notice is preserved. 8769 8770 These pages are [23]maintained by the GCC team. Last modified 8771 2021-07-28[24]. 8772 8773 References 8774 8775 1. http://www.gnu.org/ 8776 2. http://gcc.gnu.org/gcc-4.6/changes.html 8777 3. https://gcc.gnu.org/onlinedocs/4.6.4/ 8778 4. http://gcc.gnu.org/gcc-4.6/changes.html 8779 5. https://gcc.gnu.org/onlinedocs/4.6.3/ 8780 6. http://gcc.gnu.org/gcc-4.6/changes.html 8781 7. https://gcc.gnu.org/onlinedocs/4.6.2/ 8782 8. http://gcc.gnu.org/gcc-4.6/changes.html 8783 9. https://gcc.gnu.org/onlinedocs/4.6.1/ 8784 10. http://gcc.gnu.org/gcc-4.6/changes.html 8785 11. https://gcc.gnu.org/onlinedocs/4.6.0/ 8786 12. http://gcc.gnu.org/gcc-4.6/buildstat.html 8787 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 8788 14. http://gcc.gnu.org/index.html 8789 15. mailto:gcc (a] gcc.gnu.org 8790 16. http://gcc.gnu.org/mirrors.html 8791 17. http://gcc.gnu.org/git.html 8792 18. https://gcc.gnu.org/onlinedocs/ 8793 19. mailto:gcc-help (a] gcc.gnu.org 8794 20. mailto:gcc (a] gcc.gnu.org 8795 21. https://gcc.gnu.org/lists.html 8796 22. https://www.fsf.org/ 8797 23. https://gcc.gnu.org/about.html 8798 24. http://validator.w3.org/check/referer 8799 ====================================================================== 8800 http://gcc.gnu.org/gcc-4.6/changes.html 8801 GCC 4.6 Release Series 8802 Changes, New Features, and Fixes 8803 8804 Caveats 8805 8806 * The options -b <machine> and -V <version> have been removed because 8807 they were unreliable. Instead, users should directly run 8808 <machine>-gcc when cross-compiling, or <machine>-gcc-<version> to 8809 run a different version of gcc. 8810 * GCC now has stricter checks for invalid command-line options. In 8811 particular, when gcc was called to link object files rather than 8812 compile source code, it would previously accept and ignore all 8813 options starting with --, including linker options such as 8814 --as-needed and --export-dynamic, although such options would 8815 result in errors if any source code was compiled. Such options, if 8816 unknown to the compiler, are now rejected in all cases; if the 8817 intent was to pass them to the linker, options such as 8818 -Wl,--as-needed should be used. 8819 * Versions of the GNU C library up to and including 2.11.1 included 8820 an [1]incorrect implementation of the cproj function. GCC optimizes 8821 its builtin cproj according to the behavior specified and allowed 8822 by the ISO C99 standard. If you want to avoid discrepancies between 8823 the C library and GCC's builtin transformations when using cproj in 8824 your code, use GLIBC 2.12 or later. If you are using an older GLIBC 8825 and actually rely on the incorrect behavior of cproj, then you can 8826 disable GCC's transformations using -fno-builtin-cproj. 8827 * The C-only intermodule optimization framework (IMA, enabled by 8828 -combine) has been removed in favor of the new generic link-time 8829 optimization framework (LTO) introduced in [2]GCC 4.5.0. 8830 * GCC now ships with the LGPL-licensed libquadmath library, which 8831 provides quad-precision mathematical functions for targets with a 8832 __float128 datatype. __float128 is available for targets on 32-bit 8833 x86, x86-64 and Itanium architectures. The libquadmath library is 8834 automatically built on such targets when building the Fortran 8835 compiler. 8836 * New -Wunused-but-set-variable and -Wunused-but-set-parameter 8837 warnings were added for C, C++, Objective-C and Objective-C++. 8838 These warnings diagnose variables respective parameters which are 8839 only set in the code and never otherwise used. Usually such 8840 variables are useless and often even the value assigned to them is 8841 computed needlessly, sometimes expensively. The 8842 -Wunused-but-set-variable warning is enabled by default by -Wall 8843 flag and -Wunused-but-set-parameter by -Wall -Wextra flags. 8844 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 8845 rules for the layout of vectors that could lead to wrong code being 8846 generated. Vectors larger than 8 bytes in size are now by default 8847 aligned to an 8-byte boundary. This is an ABI change: code that 8848 makes explicit use of vector types may be incompatible with binary 8849 objects built with older versions of GCC. Auto-vectorized code is 8850 not affected by this change. (This change affects GCC versions 8851 4.6.4 and later, with the exception of versions 4.7.0 and 4.7.1.) 8852 * On AVR, variables with the progmem attribute to locate data in 8853 flash memory must be qualified as const. 8854 * Support for a number of older systems and recently unmaintained or 8855 untested target ports of GCC has been declared obsolete in GCC 4.6. 8856 Unless there is activity to revive them, the next release of GCC 8857 will have their sources permanently removed. 8858 All GCC ports for the following processor architectures have been 8859 declared obsolete: 8860 + Argonaut ARC (arc-*) 8861 + National Semiconductor CRX (crx-*) 8862 + Motorola 68HC11 and 68HC12 (m68hc11-*-*, m6811-*-*, 8863 m68hc12-*-*, m6812-*-*) 8864 + Sunplus S+core (score-*) 8865 The following ports for individual systems on particular 8866 architectures have been obsoleted: 8867 + Interix (i[34567]86-*-interix3*) 8868 + NetWare x86 (i[3456x]86-*-netware*) 8869 + Generic ARM PE (arm-*-pe* other than arm*-wince-pe*) 8870 + MCore PE (mcore-*-pe*) 8871 + SH SymbianOS (sh*-*-symbianelf*) 8872 + GNU Hurd on Alpha and PowerPC (alpha*-*-gnu*, powerpc*-*-gnu*) 8873 + M68K uClinux old ABI (m68k-*-uclinuxoldabi*) 8874 + a.out NetBSD (arm*-*-netbsd*, i[34567]86-*-netbsd*, 8875 vax-*-netbsd*, but not *-*-netbsdelf*) 8876 The i[34567]86-*-pe alias for Cygwin targets has also been 8877 obsoleted; users should configure for i[34567]86-*-cygwin* instead. 8878 Certain configure options to control the set of libraries built 8879 with GCC on some targets have been obsoleted. On ARM targets, the 8880 options --disable-fpu, --disable-26bit, --disable-underscore, 8881 --disable-interwork, --disable-biendian and --disable-nofmult have 8882 been obsoleted. On MIPS targets, the options 8883 --disable-single-float, --disable-biendian and --disable-softfloat 8884 have been obsoleted. 8885 * Support has been removed for all the [3]configurations obsoleted in 8886 GCC 4.5. 8887 * More information on porting to GCC 4.6 from previous versions of 8888 GCC can be found in the [4]porting guide for this release. 8889 8890 General Optimizer Improvements 8891 8892 * A new general optimization level, -Ofast, has been introduced. It 8893 combines the existing optimization level -O3 with options that can 8894 affect standards compliance but result in better optimized code. 8895 For example, -Ofast enables -ffast-math. 8896 * Link-time optimization improvements: 8897 + The [5]Scalable Whole Program Optimizer (WHOPR) project has 8898 stabilized to the point of being usable. It has become the 8899 default mode when using the LTO optimization model. Link time 8900 optimization can now split itself into multiple parallel 8901 compilations. Parallelism is controlled with -flto=n (where n 8902 specifies the number of compilations to execute in parallel). 8903 GCC can also cooperate with a GNU make job server by 8904 specifying the -flto=jobserver option and adding + to the 8905 beginning of the Makefile rule executing the linker. 8906 Classical LTO mode can be enforced by -flto-partition=none. 8907 This may result in small code quality improvements. 8908 + A large number of bugs were fixed. GCC itself, Mozilla Firefox 8909 and other large applications can be built with LTO enabled. 8910 + The linker plugin support improvements 8911 o Linker plugin is now enabled by default when the linker 8912 is detected to have plugin support. This is the case for 8913 GNU ld 2.21.51 or newer (on ELF and Cygwin targets) and 8914 the Gold linker on ELF targets. Plugin support of the 8915 Apple linker on Darwin is not compatible with GCC. The 8916 linker plugin can also be controlled by the 8917 -fuse-linker-plugin command-line option. 8918 o Resolution information from the linker plugin is used to 8919 drive whole program assumptions. Use of the linker plugin 8920 results in more aggressive optimization on binaries and 8921 on shared libraries that use the hidden visibility 8922 attribute. Consequently the use of -fwhole-program is not 8923 necessary in addition to LTO. 8924 + Hidden symbols used from non-LTO objects now have to be 8925 explicitly annotated with externally_visible when the linker 8926 plugin is not used. 8927 + C++ inline functions and virtual tables are now privatized 8928 more aggressively, leading to better inter-procedural 8929 optimization and faster dynamic linking. 8930 + Memory usage and intermediate language streaming performance 8931 have been improved. 8932 + Static constructors and destructors from individual units are 8933 inlined into a single function. This can significantly improve 8934 startup times of large C++ applications where static 8935 constructors are very common. For example, static constructors 8936 are used when including the iostream header. 8937 + Support for the Ada language has been added. 8938 * Interprocedural optimization improvements 8939 + The interprocedural framework was re-tuned for link time 8940 optimization. Several scalability issues were resolved. 8941 + Improved auto-detection of const and pure functions. Newly, 8942 noreturn functions are auto-detected. 8943 The [6]-Wsuggest-attribute=[const|pure|noreturn] flag is 8944 available that informs users when adding attributes to headers 8945 might improve code generation. 8946 + A number of inlining heuristic improvements. In particular: 8947 o Partial inlining is now supported and enabled by default 8948 at -O2 and greater. The feature can be controlled via 8949 -fpartial-inlining. 8950 Partial inlining splits functions with short hot path to 8951 return. This allows more aggressive inlining of the hot 8952 path leading to better performance and often to code size 8953 reductions (because cold parts of functions are not 8954 duplicated). 8955 o Scalability for large compilation units was improved 8956 significantly. 8957 o Inlining of callbacks is now more aggressive. 8958 o Virtual methods are considered for inlining when the 8959 caller is inlined and devirtualization is then possible. 8960 o Inlining when optimizing for size (either in cold regions 8961 of a program or when compiling with -Os) was improved to 8962 better handle C++ programs with larger abstraction 8963 penalty, leading to smaller and faster code. 8964 + The IPA reference optimization pass detecting global variables 8965 used or modified by functions was strengthened and sped up. 8966 + Functions whose address was taken are now optimized out when 8967 all references to them are dead. 8968 + A new inter-procedural static profile estimation pass detects 8969 functions that are executed once or unlikely to be executed. 8970 Unlikely executed functions are optimized for size. Functions 8971 executed once are optimized for size except for the inner 8972 loops. 8973 + On most targets with named section support, functions used 8974 only at startup (static constructors and main), functions used 8975 only at exit and functions detected to be cold are placed into 8976 separate text segment subsections. This extends the 8977 -freorder-functions feature and is controlled by the same 8978 switch. The goal is to improve the startup time of large C++ 8979 programs. 8980 Proper function placement requires linker support. GNU ld 8981 2.21.51 on ELF targets was updated to place those functions 8982 together within the text section leading to better code 8983 locality and faster startup times of large C++ programs. The 8984 feature is also supported in the Apple linker. Support in the 8985 gold linker is planned. 8986 * A new switch -fstack-usage has been added. It makes the compiler 8987 output stack usage information for the program, on a per-function 8988 basis, in an auxiliary file. 8989 * A new switch -fcombine-stack-adjustments has been added. It can be 8990 used to enable or disable the compiler's stack-slot combining pass 8991 which before was enabled automatically at -O1 and above, but could 8992 not be controlled on its own. 8993 * A new switch -fstrict-volatile-bitfields has been added. Using it 8994 indicates that accesses to volatile bitfields should use a single 8995 access of the width of the field's type. This option can be useful 8996 for precisely defining and accessing memory-mapped peripheral 8997 registers from C or C++. 8998 8999 Compile time and memory usage improvements 9000 9001 * Datastructures used by the dataflow framework in GCC were 9002 reorganized for better memory usage and more cache locality. 9003 Compile time is improved especially on units with large functions 9004 (possibly resulting from a lot of inlining) not fitting into the 9005 processor cache. The compile time of the GCC C compiler binary with 9006 link-time optimization went down by over 10% (benchmarked on x86-64 9007 target). 9008 9009 New Languages and Language specific improvements 9010 9011 Ada 9012 9013 * Stack checking has been improved on selected architectures (Alpha, 9014 IA-32/x86-64, RS/6000 and SPARC): it now will detect stack 9015 overflows in all cases on these architectures. 9016 * Initial support for Ada 2012 has been added. 9017 9018 C family 9019 9020 * A new warning, enabled by -Wdouble-promotion, has been added that 9021 warns about cases where a value of type float is implicitly 9022 promoted to double. This is especially helpful for CPUs that handle 9023 the former in hardware, but emulate the latter in software. 9024 * A new function attribute leaf was introduced. This attribute allows 9025 better inter-procedural optimization across calls to functions that 9026 return to the current unit only via returning or exception 9027 handling. This is the case for most library functions that have no 9028 callbacks. 9029 * Support for a new data type __int128 for targets having wide enough 9030 machine-mode support. 9031 * The new function attribute callee_pop_aggregate allows to specify 9032 if the caller or callee is responsible for popping the aggregate 9033 return pointer value from the stack. 9034 * Support for selectively enabling and disabling warnings via #pragma 9035 GCC diagnostic has been added. For instance: 9036 #pragma GCC diagnostic error "-Wuninitialized" 9037 foo(a); /* error is given for this one */ 9038 #pragma GCC diagnostic push 9039 #pragma GCC diagnostic ignored "-Wuninitialized" 9040 foo(b); /* no diagnostic for this one */ 9041 #pragma GCC diagnostic pop 9042 foo(c); /* error is given for this one */ 9043 #pragma GCC diagnostic pop 9044 foo(d); /* depends on command-line options */ 9045 9046 * The -fmax-errors=N option is now supported. Using this option 9047 causes the compiler to exit after N errors have been issued. 9048 9049 C 9050 9051 * There is now experimental support for some features from the 9052 upcoming C1X revision of the ISO C standard. This support may be 9053 selected with -std=c1x, or -std=gnu1x for C1X with GNU extensions. 9054 Note that this support is experimental and may change incompatibly 9055 in future releases for consistency with changes to the C1X standard 9056 draft. The following features are newly supported as described in 9057 the N1539 draft of C1X (with changes agreed at the March 2011 WG14 9058 meeting); some other features were already supported with no 9059 compiler changes being needed, or have some support but not in full 9060 accord with N1539 (as amended). 9061 + Static assertions (_Static_assert keyword) 9062 + Typedef redefinition 9063 + New macros in <float.h> 9064 + Anonymous structures and unions 9065 * The new -fplan9-extensions option directs the compiler to support 9066 some extensions for anonymous struct fields which are implemented 9067 by the Plan 9 compiler. A pointer to a struct may be automatically 9068 converted to a pointer to an anonymous field when calling a 9069 function, in order to make the types match. An anonymous struct 9070 field whose type is a typedef name may be referred to using the 9071 typedef name. 9072 9073 C++ 9074 9075 * Improved [7]experimental support for the upcoming C++0x ISO C++ 9076 standard, including support for constexpr (thanks to Gabriel Dos 9077 Reis and Jason Merrill), nullptr (thanks to Magnus Fromreide), 9078 noexcept, unrestricted unions, range-based for loops (thanks to 9079 Rodrigo Rivas Costa), opaque enum declarations (thanks also to 9080 Rodrigo), implicitly deleted functions and implicit move 9081 constructors. 9082 * When an extern declaration within a function does not match a 9083 declaration in the enclosing context, G++ now properly declares the 9084 name within the namespace of the function rather than the namespace 9085 which was open just before the function definition ([8]c++/43145). 9086 * GCC now warns by default when casting integers to larger pointer 9087 types. These warnings can be disabled with the option 9088 -Wno-int-to-pointer-cast, which is now also available in C++. 9089 * G++ no longer optimizes using the assumption that a value of 9090 enumeration type will fall within the range specified by the 9091 standard, since that assumption is easily violated with a 9092 conversion from integer type ([9]c++/43680). The old behavior can 9093 be restored with -fstrict-enums. 9094 * The new -fnothrow-opt flag changes the semantics of a throw() 9095 exception specification to match the proposed semantics of the 9096 noexcept specification: just call terminate if an exception tries 9097 to propagate out of a function with such an exception 9098 specification. This dramatically reduces or eliminates the code 9099 size overhead from adding the exception specification. 9100 * The new -Wnoexcept flag will suggest adding a noexcept qualifier to 9101 a function that the compiler can tell doesn't throw if it would 9102 change the value of a noexcept expression. 9103 * The -Wshadow option now warns if a local variable or type 9104 declaration shadows another type in C++. Note that the compiler 9105 will not warn if a local variable shadows a struct/class/enum, but 9106 will warn if it shadows an explicit typedef. 9107 * When an identifier is not found in the current scope, G++ now 9108 offers suggestions about which identifier might have been intended. 9109 * G++ now issues clearer diagnostics for missing semicolons after 9110 class, struct, and union definitions. 9111 * G++ now issues clearer diagnostics for missing semicolons after 9112 class member declarations. 9113 * G++ now issues clearer diagnostics when a colon is used in a place 9114 where a double-colon was intended. 9115 * G++ no longer accepts mutable on reference members ([10]c++/33558). 9116 Use -fpermissive to allow the old, non-conforming behaviour. 9117 * A few mangling fixes have been made, to attribute const/volatile on 9118 function pointer types, decltype of a plain decl, and use of a 9119 function parameter in the declaration of another parameter. By 9120 default the compiler still uses the old mangling, but emits aliases 9121 with the new mangling on targets that support strong aliases. Users 9122 can switch over entirely to the new mangling with -fabi-version=5 9123 or -fabi-version=0. -Wabi will now warn about code that uses the 9124 old mangling. 9125 * In 4.6.0 and 4.6.1 G++ no longer allows objects of const-qualified 9126 type to be default initialized unless the type has a user-declared 9127 default constructor. In 4.6.2 G++ implements the proposed 9128 resolution of [11]DR 253, so default initialization is allowed if 9129 it initializes all subobjects. Code that fails to compile can be 9130 fixed by providing an initializer e.g. 9131 struct A { A(); }; 9132 struct B : A { int i; }; 9133 const B b = B(); 9134 Use -fpermissive to allow the old, non-conforming behaviour. 9135 9136 Runtime Library (libstdc++) 9137 9138 * [12]Improved experimental support for the upcoming ISO C++ 9139 standard, C++0x, including using constexpr and nullptr. 9140 * Performance improvements to the [13]Debug Mode, thanks to Franois 9141 Dumont. 9142 * Atomic operations used for reference-counting are annotated so that 9143 they can be understood by race detectors such as Helgrind, see 9144 [14]Data Race Hunting. 9145 * Most libstdc++ standard headers have been changed to no longer 9146 include the cstddef header as an implementation detail. Code that 9147 relied on that header being included as side-effect of including 9148 other standard headers will need to include cstddef explicitly. 9149 9150 Fortran 9151 9152 * On systems supporting the libquadmath library, GNU Fortran now also 9153 supports a quad-precision, kind=16 floating-point data type 9154 (REAL(16), COMPLEX(16)). As the data type is not fully supported in 9155 hardware, calculations might be one to two orders of magnitude 9156 slower than with the 4, 8 or 10 bytes floating-point data types. 9157 This change does not affect systems which support REAL(16) in 9158 hardware nor those which do not support libquadmath. 9159 * Much improved compile time for large array constructors. 9160 * In order to reduce execution time and memory consumption, use of 9161 temporary arrays in assignment expressions is avoided for many 9162 cases. The compiler now reverses loops in order to avoid generating 9163 a temporary array where possible. 9164 * Improved diagnostics, especially with -fwhole-file. 9165 * The -fwhole-file flag is now enabled by default. This improves code 9166 generation and diagnostics. It can be disabled using the deprecated 9167 -fno-whole-file flag. 9168 * Support the generation of Makefile dependencies via the [15]-M... 9169 flags of GCC; you may need to specify the -cpp option in addition. 9170 The dependencies take modules, Fortran's include, and CPP's 9171 #include into account. Note: Using -M for the module path is no 9172 longer supported, use -J instead. 9173 * The flag -Wconversion has been modified to only issue warnings 9174 where a conversion leads to information loss. This drastically 9175 reduces the number of warnings; -Wconversion is thus now enabled 9176 with -Wall. The flag -Wconversion-extra has been added and also 9177 warns about other conversions; -Wconversion-extra typically issues 9178 a huge number of warnings, most of which can be ignored. 9179 * A new command-line option -Wunused-dummy-argument warns about 9180 unused dummy arguments and is included in -Wall. Before, 9181 -Wunused-variable also warned about unused dummy arguments. 9182 * Fortran 2003 support has been extended: 9183 + Improved support for polymorphism between libraries and 9184 programs and for complicated inheritance patterns (cf. 9185 [16]object-oriented programming). 9186 + Experimental support of the ASSOCIATE construct. 9187 + In pointer assignments it is now possible to specify the lower 9188 bounds of the pointer and, for a rank-1 or a simply contiguous 9189 data-target, to remap the bounds. 9190 + Automatic (re)allocation: In intrinsic assignments to 9191 allocatable variables the left-hand side will be automatically 9192 allocated (if unallocated) or reallocated (if the shape or 9193 type parameter is different). To avoid the small performance 9194 penalty, you can use a(:) = ... instead of a = ... for arrays 9195 and character strings or disable the feature using -std=f95 9196 or -fno-realloc-lhs. 9197 + Deferred type parameter: For scalar allocatable and pointer 9198 variables the character length can be deferred. 9199 + Namelist variables with allocatable and pointer attribute and 9200 nonconstant length type parameter are supported. 9201 * Fortran 2008 support has been extended: 9202 + Experimental [17]coarray support (for one image only, i.e. 9203 num_images() == 1); use the [18]-fcoarray=single flag to 9204 enable it. 9205 + The STOP and the new ERROR STOP statements now support all 9206 constant expressions. 9207 + Support for the CONTIGUOUS attribute. 9208 + Support for ALLOCATE with MOLD. 9209 + Support for the STORAGE_SIZE intrinsic inquiry function. 9210 + Support of the NORM2 and PARITY intrinsic functions. 9211 + The following bit intrinsics were added: POPCNT and POPPAR for 9212 counting the number of 1 bits and returning the parity; BGE, 9213 BGT, BLE, and BLT for bitwise comparisons; DSHIFTL and DSHIFTR 9214 for combined left and right shifts, MASKL and MASKR for simple 9215 left and right justified masks, MERGE_BITS for a bitwise merge 9216 using a mask, SHIFTA, SHIFTL and SHIFTR for shift operations, 9217 and the transformational bit intrinsics IALL, IANY and 9218 IPARITY. 9219 + Support of the EXECUTE_COMMAND_LINE intrinsic subroutine. 9220 + Support for the IMPURE attribute for procedures, which allows 9221 for ELEMENTAL procedures without the restrictions of PURE. 9222 + Null pointers (including NULL()) and not allocated variables 9223 can be used as actual argument to optional non-pointer, 9224 non-allocatable dummy arguments, denoting an absent argument. 9225 + Non-pointer variables with TARGET attribute can be used as 9226 actual argument to POINTER dummies with INTENT(IN) 9227 + Pointers including procedure pointers and those in a derived 9228 type (pointer components) can now be initialized by a target 9229 instead of only by NULL. 9230 + The EXIT statement (with construct-name) can now be used to 9231 leave not only the DO but also the ASSOCIATE, BLOCK, IF, 9232 SELECT CASE and SELECT TYPE constructs. 9233 + Internal procedures can now be used as actual argument. 9234 + The named constants INTEGER_KINDS, LOGICAL_KINDS, REAL_KINDS 9235 and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV 9236 have been added; these arrays contain the supported kind 9237 values for the respective types. 9238 + The module procedures C_SIZEOF of the intrinsic module 9239 ISO_C_BINDINGS and COMPILER_VERSION and COMPILER_OPTIONS of 9240 ISO_FORTRAN_ENV have been implemented. 9241 + Minor changes: obsolescence diagnostics for ENTRY was added 9242 for -std=f2008; a line may start with a semicolon; for 9243 internal and module procedures END can be used instead of END 9244 SUBROUTINE and END FUNCTION; SELECTED_REAL_KIND now also takes 9245 a RADIX argument; intrinsic types are supported for 9246 TYPE(intrinsic-type-spec); multiple type-bound procedures can 9247 be declared in a single PROCEDURE statement; implied-shape 9248 arrays are supported for named constants (PARAMETER). The 9249 transformational, three argument versions of BESSEL_JN and 9250 BESSEL_YN were added the elemental, two-argument version had 9251 been added in GCC 4.4; note that the transformational 9252 functions use a recurrence algorithm. 9253 9254 Go 9255 9256 Support for the Go programming language has been added to GCC. It is 9257 not enabled by default when you build GCC; use the --enable-languages 9258 configure option to build it. The driver program for compiling Go code 9259 is gccgo. 9260 9261 Go is currently known to work on GNU/Linux and RTEMS. Solaris support 9262 is in progress. It may or may not work on other platforms. 9263 9264 Objective-C and Objective-C++ 9265 9266 * The -fobjc-exceptions flag is now required to enable Objective-C 9267 exception and synchronization syntax (introduced by the keywords 9268 @try, @catch, @finally and @synchronized). 9269 * A number of Objective-C 2.0 features and extensions are now 9270 supported by GCC. These features are enabled by default; you can 9271 disable them by using the new -fobjc-std=objc1 command-line option. 9272 * The Objective-C 2.0 dot-syntax is now supported. It is an 9273 alternative syntax for using getters and setters; object.count is 9274 automatically converted into [object count] or [object setCount: 9275 ...] depending on context; for example if (object.count > 0) is 9276 automatically compiled into the equivalent of if ([object count] > 9277 0) while object.count = 0; is automatically compiled into the 9278 equivalent ot [object setCount: 0];. The dot-syntax can be used 9279 with instance and class objects and with any setters or getters, no 9280 matter if they are part of a declared property or not. 9281 * Objective-C 2.0 declared properties are now supported. They are 9282 declared using the new @property keyword, and are most commonly 9283 used in conjunction with the new Objective-C 2.0 dot-syntax. The 9284 nonatomic, readonly, readwrite, assign, retain, copy, setter and 9285 getter attributes are all supported. Marking declared properties 9286 with __attribute__ ((deprecated)) is supported too. 9287 * The Objective-C 2.0 @synthesize and @dynamic keywords are 9288 supported. @synthesize causes the compiler to automatically 9289 synthesize a declared property, while @dynamic is used to disable 9290 all warnings for a declared property for which no implementation is 9291 provided at compile time. Synthesizing declared properties requires 9292 runtime support in most useful cases; to be able to use it with the 9293 GNU runtime, appropriate helper functions have been added to the 9294 GNU Objective-C runtime ABI, and are implemented by the GNU 9295 Objective-C runtime library shipped with GCC. 9296 * The Objective-C 2.0 fast enumeration syntax is supported in 9297 Objective-C. This is currently not yet available in Objective-C++. 9298 Fast enumeration requires support in the runtime, and such support 9299 has been added to the GNU Objective-C runtime library (shipped with 9300 GCC). 9301 * The Objective-C 2.0 @optional keyword is supported. It allows you 9302 to mark methods or properties in a protocol as optional as opposed 9303 to required. 9304 * The Objective-C 2.0 @package keyword is supported. It has currently 9305 the same effect as the @public keyword. 9306 * Objective-C 2.0 method attributes are supported. Currently the 9307 supported attributes are deprecated, sentinel, noreturn and format. 9308 * Objective-C 2.0 method argument attributes are supported. The most 9309 widely used attribute is unused, to mark an argument as unused in 9310 the implementation. 9311 * Objective-C 2.0 class and protocol attributes are supported. 9312 Currently the only supported attribute is deprecated. 9313 * Objective-C 2.0 class extensions are supported. A class extension 9314 has the same syntax as a category declaration with no category 9315 name, and the methods and properties declared in it are added 9316 directly to the main class. It is mostly used as an alternative to 9317 a category to add methods to a class without advertising them in 9318 the public headers, with the advantage that for class extensions 9319 the compiler checks that all the privately declared methods are 9320 actually implemented. 9321 * As a result of these enhancements, GCC can now be used to build 9322 Objective-C and Objective-C++ software that uses Foundation and 9323 other important system frameworks with the NeXT runtime on Darwin 9 9324 and Darwin 10 (OSX 10.5 and 10.6). 9325 * Many bugs in the compiler have been fixed in this release; in 9326 particular, LTO can now be used when compiling Objective-C and 9327 Objective-C++ and the parser is much more robust in dealing with 9328 invalid code. 9329 9330 Runtime Library (libobjc) 9331 9332 * The GNU Objective-C runtime library now defines the macro 9333 __GNU_LIBOBJC__ (with a value that is increased at every release 9334 where there is any change to the API) in objc/objc.h, making it 9335 easy to determine if the GNU Objective-C runtime library is being 9336 used, and if so, which version. Previous versions of the GNU 9337 Objective-C runtime library (and other Objective-C runtime 9338 libraries such as the Apple one) do not define this macro. 9339 * A new Objective-C 2.0 API, almost identical to the one implemented 9340 by the Apple Objective-C runtime, has been implemented in the GNU 9341 Objective-C runtime library. The new API hides the internals of 9342 most runtime structures but provides a more extensive set of 9343 functions to operate on them. It is much easier, for example, to 9344 create or modify classes at runtime. The new API also makes it 9345 easier to port software from Apple to GNU as almost no changes 9346 should be required. The old API is still supported for backwards 9347 compatibility; including the old objc/objc-api.h header file 9348 automatically selects the old API, while including the new 9349 objc/runtime.h header file automatically selects the new API. 9350 Support for the old API is being phased out and upgrading the 9351 software to use the new API is strongly recommended. To check for 9352 the availability of the new API, the __GNU_LIBOBJC__ macro can be 9353 used as older versions of the GNU Objective-C runtime library, 9354 which do not support the new API, do not define such a macro. 9355 * Runtime support for @synchronized has been added. 9356 * Runtime support for Objective-C 2.0 synthesized property accessors 9357 has been added. 9358 * Runtime support for Objective-C 2.0 fast enumeration has been 9359 added. 9360 9361 New Targets and Target Specific Improvements 9362 9363 ARM 9364 9365 * GCC now supports the Cortex-M4 processor implementing the v7-em 9366 version of the architecture using the option -mcpu=cortex-m4. 9367 * Scheduling descriptions for the Cortex-M4, the Neon and the 9368 floating point units of the Cortex-A9 and a pipeline description 9369 for the Cortex-A5 have been added. 9370 * Synchronization primitives such as __sync_fetch_and_add and friends 9371 are now inlined for supported architectures rather than calling 9372 into a kernel helper function. 9373 * SSA loop prefetching is enabled by default for the Cortex-A9 at 9374 -O3. 9375 * Several improvements were committed to improve code generation for 9376 the ARM architecture including a rewritten implementation for load 9377 and store multiples. 9378 * Several enhancements were committed to improve SIMD code generation 9379 for NEON by adding support for widening instructions, misaligned 9380 loads and stores, vector conditionals and support for 64 bit 9381 arithmetic. 9382 * Support was added for the Faraday cores fa526, fa606te, fa626te, 9383 fmp626te, fmp626 and fa726te and can be used with the respective 9384 names as parameters to the -mcpu= option. 9385 * Basic support was added for Cortex-A15 and is available through 9386 -mcpu=cortex-a15. 9387 * GCC for AAPCS configurations now more closely adheres to the AAPCS 9388 specification by enabling -fstrict-volatile-bitfields by default. 9389 9390 IA-32/x86-64 9391 9392 * The new -fsplit-stack option permits programs to use a 9393 discontiguous stack. This is useful for threaded programs, in that 9394 it is no longer necessary to specify the maximum stack size when 9395 creating a thread. This feature is currently only implemented for 9396 32-bit and 64-bit x86 GNU/Linux targets. 9397 * Support for emitting profiler counter calls before function 9398 prologues. This is enabled via a new command-line option -mfentry. 9399 * Optimization for the Intel Core 2 processors is now available 9400 through the -march=core2 and -mtune=core2 options. 9401 * Support for Intel Core i3/i5/i7 processors is now available through 9402 the -march=corei7 and -mtune=corei7 options. 9403 * Support for Intel Core i3/i5/i7 processors with AVX is now 9404 available through the -march=corei7-avx and -mtune=corei7-avx 9405 options. 9406 * Support for AMD Bobcat (family 14) processors is now available 9407 through the -march=btver1 and -mtune=btver1 options. 9408 * Support for AMD Bulldozer (family 15) processors is now available 9409 through the -march=bdver1 and -mtune=bdver1 options. 9410 * The default setting (when not optimizing for size) for 32-bit 9411 GNU/Linux and Darwin x86 targets has been changed to 9412 -fomit-frame-pointer. The default can be reverted to 9413 -fno-omit-frame-pointer by configuring GCC with the 9414 --enable-frame-pointer configure option. 9415 * Darwin, FreeBSD, Solaris 2, MinGW and Cygwin now all support 9416 __float128 on 32-bit and 64-bit x86 targets. 9417 * AVX floating-point arithmetic can now be enabled by default at 9418 configure time with the new --with-fpmath=avx option. 9419 * The SSA loop prefetching pass is enabled when using -O3 when 9420 optimizing for CPUs where prefetching is beneficial (AMD CPUs newer 9421 than K6). 9422 * Support for TBM (Trailing Bit Manipulation) built-in functions and 9423 code generation is available via -mtbm. 9424 * Support for AMD's BMI (Bit Manipulation) built-in functions and 9425 code generation is available via -mbmi. 9426 9427 MicroBlaze 9428 9429 * Support has been added for the Xilinx MicroBlaze softcore processor 9430 (microblaze-elf) embedded target. This configurable processor is 9431 supported on several Xilinx Spartan and Virtex FPGAs. 9432 9433 MIPS 9434 9435 * GCC now supports the Loongson 3A processor. Its canonical -march= 9436 and -mtune= name is loongson3a. 9437 9438 MN10300 / AM33 9439 9440 * The inline assembly register constraint "A" has been renamed "c". 9441 This constraint is used to select a floating-point register that 9442 can be used as the destination of a multiply-accumulate 9443 instruction. 9444 * New inline assembly register constraints "A" and "D" have been 9445 added. These constraint letters resolve to all general registers 9446 when compiling for AM33, and resolve to address registers only or 9447 data registers only when compiling for MN10300. 9448 * The MDR register is represented in the compiler. One can access the 9449 register via the "z" constraint in inline assembly. It can be 9450 marked as clobbered or used as a local register variable via the 9451 "mdr" name. The compiler uses the RETF instruction if the function 9452 does not modify the MDR register, so it is important that inline 9453 assembly properly annotate any usage of the register. 9454 9455 PowerPC/PowerPC64 9456 9457 * GCC now supports the Applied Micro Titan processor with 9458 -mcpu=titan. 9459 * The -mrecip option has been added, which indicates whether the 9460 reciprocal and reciprocal square root instructions should be used. 9461 * The -mveclibabi=mass option can be used to enable the compiler to 9462 autovectorize mathematical functions using the Mathematical 9463 Acceleration Subsystem library. 9464 * The -msingle-pic-base option has been added, which instructs the 9465 compiler to avoid loading the PIC base register in function 9466 prologues. The PIC base register must be initialized by the runtime 9467 system. 9468 * The -mblock-move-inline-limit option has been added, which enables 9469 the user to control the maximum size of inlined memcpy calls and 9470 similar. 9471 * PowerPC64 GNU/Linux support for applications requiring a large TOC 9472 section has been improved. A new command-line option, 9473 -mcmodel=MODEL, controls this feature; valid values for MODEL are 9474 small, medium, or large. 9475 * The Altivec builtin functions vec_ld and vec_st have been modified 9476 to generate the Altivec memory instructions LVX and STVX, even if 9477 the -mvsx option is used. In the initial GCC 4.5 release, these 9478 builtin functions were changed to generate VSX memory reference 9479 instructions instead of Altivec memory instructions, but there are 9480 differences between the two instructions. If the VSX instruction 9481 set is available, you can now use the new builtin functions 9482 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 9483 instructions. 9484 * The GCC compiler on AIX now defaults to a process layout with a 9485 larger data space allowing larger programs to be compiled. 9486 * The GCC long double type on AIX 6.1 and above has reverted to 64 9487 bit double precision, matching the AIX XL compiler default, because 9488 of missing C99 symbols required by the GCC runtime. 9489 * The default processor scheduling model and tuning for PowerPC64 9490 GNU/Linux and for AIX 6.1 and above now is POWER7. 9491 * Starting with GCC 4.6.1, vectors of type vector long long or vector 9492 long are passed and returned in the same method as other vectors 9493 with the VSX instruction set. Previously the GCC compiler did not 9494 adhere to the ABI for 128-bit vectors with 64-bit integer base 9495 types (PR 48857). This is also fixed in the GCC 4.5.4 release. 9496 9497 S/390, zSeries and System z9/z10, IBM zEnterprise z196 9498 9499 * Support for the zEnterprise z196 processor has been added. When 9500 using the -march=z196 option, the compiler will generate code 9501 making use of the following instruction facilities: 9502 + Conditional load/store 9503 + Distinct-operands 9504 + Floating-point-extension 9505 + Interlocked-access 9506 + Population-count 9507 The -mtune=z196 option avoids the compare and branch instructions 9508 as well as the load address instruction with an index register as 9509 much as possible and performs instruction scheduling appropriate 9510 for the new out-of-order pipeline architecture. 9511 * When using the -m31 -mzarch options the generated code still 9512 conforms to the 32-bit ABI but uses the general purpose registers 9513 as 64-bit registers internally. This requires a Linux kernel saving 9514 the whole 64-bit registers when doing a context switch. Kernels 9515 providing that feature indicate that by the 'highgprs' string in 9516 /proc/cpuinfo. 9517 * The SSA loop prefetching pass is enabled when using -O3. 9518 9519 SPARC 9520 9521 * GCC now supports the LEON series of SPARC V8 processors. The code 9522 generated by the compiler can either be tuned to it by means of the 9523 --with-tune=leon configure option and -mtune=leon compilation 9524 option, or the compiler can be built for the sparc-leon-{elf,linux} 9525 and sparc-leon3-{elf,linux} targets directly. 9526 * GCC has stopped sign/zero-extending parameter registers in the 9527 callee for functions taking parameters with sub-word size in 32-bit 9528 mode, since this is redundant with the specification of the ABI. 9529 GCC has never done so in 64-bit mode since this is also redundant. 9530 * The command-line option -mfix-at697f has been added to enable the 9531 documented workaround for the single erratum of the Atmel AT697F 9532 processor. 9533 9534 Operating Systems 9535 9536 Android 9537 9538 * GCC now supports the Bionic C library and provides a convenient way 9539 of building native libraries and applications for the Android 9540 platform. Refer to the documentation of the -mandroid and -mbionic 9541 options for details on building native code. At the moment, Android 9542 support is enabled only for ARM. 9543 9544 Darwin/Mac OS X 9545 9546 * General 9547 + Initial support for CFString types has been added. 9548 This allows GCC to build projects including the system Core 9549 Foundation frameworks. The GCC Objective-C family supports 9550 CFString "toll-free bridged" as per the Mac OS X system tools. 9551 CFString is also recognized in the context of format 9552 attributes and arguments (see the documentation for format 9553 attributes for limitations). At present, 8-bit character types 9554 are supported. 9555 + Object file size reduction. 9556 The Darwin zeroed memory allocators have been re-written to 9557 make more use of .zerofill sections. For non-debug code, this 9558 can reduce object file size significantly. 9559 + Objective-C family 64-bit support (NeXT ABI 2). 9560 Initial support has been added to support 64-bit Objective-C 9561 code using the Darwin/OS X native (NeXT) runtime. ABI version 9562 2 will be selected automatically when 64-bit code is built. 9563 + Objective-C family 32-bit ABI 1. 9564 For 32-bit code ABI 1 is also now also allowed. At present it 9565 must be selected manually using -fobjc-abi-version=1 where 9566 applicable - i.e. on Darwin 9/10 (OS X 10.5/10.6). 9567 * x86 Architecture 9568 + The -mdynamic-no-pic option has been enabled. 9569 Code supporting -mdynamic-no-pic optimization has been added 9570 and is applicable to -m32 builds. The compiler bootstrap uses 9571 the option where appropriate. 9572 + The default value for -mtune= has been changed. 9573 Since Darwin systems are primarily Xeon, Core-2 or similar the 9574 default tuning has been changed to -mtune=core2. 9575 + Enable 128-bit long double (__float128) support on Darwin. 9576 * PPC Architecture 9577 + Darwin64 ABI. 9578 Several significant bugs have been fixed, such that GCC now 9579 produces code compatible with the Darwin64 PowerPC ABI. 9580 + libffi and boehm-gc. 9581 The Darwin ports of the libffi and boehm-gc libraries have 9582 been upgraded to include a Darwin64 implementation. This means 9583 that powerpc*-*-darwin9 platforms may now, for example, build 9584 Java applications with -m64 enabled. 9585 + Plug-in support has been enabled. 9586 + The -fsection-anchors option is now available although, 9587 presently, not heavily tested. 9588 9589 Solaris 2 9590 9591 New Features 9592 9593 * Support symbol versioning with the Sun linker. 9594 * Allow libstdc++ to leverage full ISO C99 support on Solaris 10+. 9595 * Support thread-local storage (TLS) with the Sun assembler on 9596 Solaris 2/x86. 9597 * Support TLS on Solaris 8/9 if prerequisites are met. 9598 * Support COMDAT group with the GNU assembler and recent Sun linker. 9599 * Support the Sun assembler visibility syntax. 9600 * Default Solaris 2/x86 to -march=pentium4 (Solaris 10+) resp. 9601 -march=pentiumpro (Solaris 8/9). 9602 * Don't use SSE on Solaris 8/9 x86 by default. 9603 * Enable 128-bit long double (__float128) support on Solaris 2/x86. 9604 9605 ABI Change 9606 9607 * Change the ABI for returning 8-byte vectors like __m64 in MMX 9608 registers on Solaris 10+/x86 to match the Sun Studio 12.1+ 9609 compilers. This is an incompatible change. If you use such types, 9610 you must either recompile all your code with the new compiler or 9611 use the new -mvect8-ret-in-mem option to remain compatible with 9612 previous versions of GCC and Sun Studio. 9613 9614 Windows x86/x86_64 9615 9616 * Initial support for decimal floating point. 9617 * Support for the __thiscall calling-convention. 9618 * Support for hot-patchable function prologues via the 9619 ms_hook_prologue attribute for x86_64 in addition to 32-bit x86. 9620 * Improvements of stack-probing and stack-allocation mechanisms. 9621 * Support of push/pop-macro pragma as preprocessor command. 9622 With #pragma push_macro("macro-name") the current definition of 9623 macro-name is saved and can be restored with #pragma 9624 pop_macro("macro-name") to its saved definition. 9625 * Enable 128-bit long double (__float128) support on MinGW and 9626 Cygwin. 9627 9628 Other significant improvements 9629 9630 Installation changes 9631 9632 * An install-strip make target is provided that installs stripped 9633 executables, and may install libraries with unneeded or debugging 9634 sections stripped. 9635 * On Power7 systems, there is a potential problem if you build the 9636 GCC compiler with a host compiler using options that enable the VSX 9637 instruction set generation. If the host compiler has been patched 9638 so that the vec_ld and vec_st builtin functions generate Altivec 9639 memory instructions instead of VSX memory instructions, then you 9640 should be able to build the compiler with VSX instruction 9641 generation. 9642 9643 Changes for GCC Developers 9644 9645 Note: these changes concern developers that develop GCC itself or 9646 software that integrates with GCC, such as plugins, and not the general 9647 GCC users. 9648 * The gengtype utility, which previously was internal to the GCC 9649 build process, has been enchanced to provide GC root information 9650 for plugins as necessary. 9651 * The old GC allocation interface of ggc_alloc and friends was 9652 replaced with a type-safe alternative. 9653 9654 GCC 4.6.1 9655 9656 This is the [19]list of problem reports (PRs) from GCC's bug tracking 9657 system that are known to be fixed in the 4.6.1 release. This list might 9658 not be complete (that is, it is possible that some PRs that have been 9659 fixed are not listed here). 9660 9661 GCC 4.6.2 9662 9663 This is the [20]list of problem reports (PRs) from GCC's bug tracking 9664 system that are known to be fixed in the 4.6.2 release. This list might 9665 not be complete (that is, it is possible that some PRs that have been 9666 fixed are not listed here). 9667 9668 GCC 4.6.3 9669 9670 This is the [21]list of problem reports (PRs) from GCC's bug tracking 9671 system that are known to be fixed in the 4.6.3 release. This list might 9672 not be complete (that is, it is possible that some PRs that have been 9673 fixed are not listed here). 9674 9675 GCC 4.6.4 9676 9677 This is the [22]list of problem reports (PRs) from GCC's bug tracking 9678 system that are known to be fixed in the 4.6.4 release. This list might 9679 not be complete (that is, it is possible that some PRs that have been 9680 fixed are not listed here). 9681 9682 9683 For questions related to the use of GCC, please consult these web 9684 pages and the [23]GCC manuals. If that fails, the 9685 [24]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9686 web pages and the development of GCC are welcome on our developer 9687 list at [25]gcc (a] gcc.gnu.org. All of [26]our lists have public 9688 archives. 9689 9690 Copyright (C) [27]Free Software Foundation, Inc. Verbatim copying and 9691 distribution of this entire article is permitted in any medium, 9692 provided this notice is preserved. 9693 9694 These pages are [28]maintained by the GCC team. Last modified 9695 2021-12-05[29]. 9696 9697 References 9698 9699 1. https://sourceware.org/bugzilla/show_bug.cgi?id=10401 9700 2. http://gcc.gnu.org/gcc-4.5/changes.html 9701 3. http://gcc.gnu.org/gcc-4.5/changes.html#obsoleted 9702 4. http://gcc.gnu.org/gcc-4.6/porting_to.html 9703 5. http://gcc.gnu.org/projects/lto/whopr.pdf 9704 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 9705 7. http://gcc.gnu.org/gcc-4.6/cxx0x_status.html 9706 8. https://gcc.gnu.org/PR43145 9707 9. https://gcc.gnu.org/PR43680 9708 10. https://gcc.gnu.org/PR33558 9709 11. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253 9710 12. https://gcc.gnu.org/onlinedocs/gcc-4.6.4/libstdc++/manual/manual/status.html#status.iso.200x 9711 13. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode.html 9712 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html#debug.races 9713 15. https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html 9714 16. https://gcc.gnu.org/wiki/OOP 9715 17. https://gcc.gnu.org/wiki/Coarray 9716 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcoarray_007d-233 9717 19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.1 9718 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.2 9719 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.3 9720 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.4 9721 23. https://gcc.gnu.org/onlinedocs/ 9722 24. mailto:gcc-help (a] gcc.gnu.org 9723 25. mailto:gcc (a] gcc.gnu.org 9724 26. https://gcc.gnu.org/lists.html 9725 27. https://www.fsf.org/ 9726 28. https://gcc.gnu.org/about.html 9727 29. http://validator.w3.org/check/referer 9728 ====================================================================== 9729 http://gcc.gnu.org/gcc-4.5/index.html 9730 GCC 4.5 Release Series 9731 9732 (This release series is no longer supported.) 9733 9734 Jul 2, 2012 9735 9736 The [1]GNU project and the GCC developers are pleased to announce the 9737 release of GCC 4.5.4. 9738 9739 This release is a bug-fix release, containing fixes for regressions in 9740 GCC 4.5.3 relative to previous releases of GCC. 9741 9742 Release History 9743 9744 GCC 4.5.4 9745 Jul 2, 2012 ([2]changes) 9746 9747 GCC 4.5.3 9748 Apr 28, 2011 ([3]changes) 9749 9750 GCC 4.5.2 9751 Dec 16, 2010 ([4]changes) 9752 9753 GCC 4.5.1 9754 Jul 31, 2010 ([5]changes) 9755 9756 GCC 4.5.0 9757 April 14, 2010 ([6]changes) 9758 9759 References and Acknowledgements 9760 9761 GCC used to stand for the GNU C Compiler, but since the compiler 9762 supports several other languages aside from C, it now stands for the 9763 GNU Compiler Collection. 9764 9765 A list of [7]successful builds is updated as new information becomes 9766 available. 9767 9768 The GCC developers would like to thank the numerous people that have 9769 contributed new features, improvements, bug fixes, and other changes as 9770 well as test results to GCC. This [8]amazing group of volunteers is 9771 what makes GCC successful. 9772 9773 For additional information about GCC please refer to the [9]GCC project 9774 web site or contact the [10]GCC development mailing list. 9775 9776 To obtain GCC please use [11]our mirror sites or [12]our version 9777 control system. 9778 9779 9780 For questions related to the use of GCC, please consult these web 9781 pages and the [13]GCC manuals. If that fails, the 9782 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9783 web pages and the development of GCC are welcome on our developer 9784 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 9785 archives. 9786 9787 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 9788 distribution of this entire article is permitted in any medium, 9789 provided this notice is preserved. 9790 9791 These pages are [18]maintained by the GCC team. Last modified 9792 2021-07-28[19]. 9793 9794 References 9795 9796 1. http://www.gnu.org/ 9797 2. http://gcc.gnu.org/gcc-4.5/changes.html 9798 3. http://gcc.gnu.org/gcc-4.5/changes.html 9799 4. http://gcc.gnu.org/gcc-4.5/changes.html 9800 5. http://gcc.gnu.org/gcc-4.5/changes.html 9801 6. http://gcc.gnu.org/gcc-4.5/changes.html 9802 7. http://gcc.gnu.org/gcc-4.5/buildstat.html 9803 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 9804 9. http://gcc.gnu.org/index.html 9805 10. mailto:gcc (a] gcc.gnu.org 9806 11. http://gcc.gnu.org/mirrors.html 9807 12. http://gcc.gnu.org/git.html 9808 13. https://gcc.gnu.org/onlinedocs/ 9809 14. mailto:gcc-help (a] gcc.gnu.org 9810 15. mailto:gcc (a] gcc.gnu.org 9811 16. https://gcc.gnu.org/lists.html 9812 17. https://www.fsf.org/ 9813 18. https://gcc.gnu.org/about.html 9814 19. http://validator.w3.org/check/referer 9815 ====================================================================== 9816 http://gcc.gnu.org/gcc-4.5/changes.html 9817 GCC 4.5 Release Series 9818 Changes, New Features, and Fixes 9819 9820 Caveats 9821 9822 * GCC now requires the [1]MPC library in order to build. See the 9823 [2]prerequisites page for version requirements. 9824 * Support for a number of older systems and recently unmaintained or 9825 untested target ports of GCC has been declared obsolete in GCC 4.5. 9826 Unless there is activity to revive them, the next release of GCC 9827 will have their sources permanently removed. 9828 The following ports for individual systems on particular 9829 architectures have been obsoleted: 9830 + IRIX releases before 6.5 (mips-sgi-irix5*, 9831 mips-sgi-irix6.[0-4]) 9832 + Solaris 7 (*-*-solaris2.7) 9833 + Tru64 UNIX releases before V5.1 (alpha*-dec-osf4*, 9834 alpha-dec-osf5.0*) 9835 + Details for the IRIX, Solaris 7, and Tru64 UNIX obsoletions 9836 can be found in the [3]announcement. 9837 Support for the classic POWER architecture implemented in the 9838 original RIOS and RIOS2 processors of the old IBM RS/6000 product 9839 line has been obsoleted in the rs6000 port. This does not affect 9840 the new generation Power and PowerPC architectures. 9841 * Support has been removed for all the [4]configurations obsoleted in 9842 GCC 4.4. 9843 * Support has been removed for the protoize and unprotoize utilities, 9844 obsoleted in GCC 4.4. 9845 * Support has been removed for tuning for Itanium1 (Merced) variants. 9846 Note that code tuned for Itanium2 should also run correctly on 9847 Itanium1. 9848 * GCC now generates unwind info also for epilogues. DWARF debuginfo 9849 generated by GCC now uses more features of DWARF3 than before, and 9850 also some DWARF4 features. GDB older than 7.0 is not able to handle 9851 either of these, so to debug GCC 4.5 generated binaries or 9852 libraries GDB 7.0 or later is needed. You can disable use of DWARF4 9853 features with the -gdwarf-3 -gstrict-dwarf options, or use 9854 -gdwarf-2 -gstrict-dwarf to restrict GCC to just DWARF2, but 9855 epilogue unwind info is emitted unconditionally whenever unwind 9856 info is emitted. 9857 * On x86 targets, code containing floating-point calculations may run 9858 significantly more slowly when compiled with GCC 4.5 in strict C99 9859 conformance mode than they did with earlier GCC versions. This is 9860 due to stricter standard conformance of the compiler and can be 9861 avoided by using the option -fexcess-precision=fast; also see 9862 [5]below. 9863 * The function attribute noinline no longer prevents GCC from cloning 9864 the function. A new attribute noclone has been introduced for this 9865 purpose. Cloning a function means that it is duplicated and the new 9866 copy is specialized for certain contexts (for example when a 9867 parameter is a known constant). 9868 9869 General Optimizer Improvements 9870 9871 * The -save-temps now takes an optional argument. The -save-temps and 9872 -save-temps=cwd switches write the temporary files in the current 9873 working directory based on the original source file. The 9874 -save-temps=obj switch will write files into the directory 9875 specified with the -o option, and the intermediate filenames are 9876 based on the output file. This will allow the user to get the 9877 compiler intermediate files when doing parallel builds without two 9878 builds of the same filename located in different directories from 9879 interfering with each other. 9880 * Debugging dumps are now created in the same directory as the object 9881 file rather than in the current working directory. This allows the 9882 user to get debugging dumps when doing parallel builds without two 9883 builds of the same filename interfering with each other. 9884 * GCC has been integrated with the MPC library. This allows GCC to 9885 evaluate complex arithmetic at compile time [6]more accurately. It 9886 also allows GCC to evaluate calls to complex built-in math 9887 functions having constant arguments and replace them at compile 9888 time with their mathematically equivalent results. In doing so, GCC 9889 can generate correct results regardless of the math library 9890 implementation or floating point precision of the host platform. 9891 This also allows GCC to generate identical results regardless of 9892 whether one compiles in native or cross-compile configurations to a 9893 particular target. The following built-in functions take advantage 9894 of this new capability: cacos, cacosh, casin, casinh, catan, 9895 catanh, ccos, ccosh, cexp, clog, cpow, csin, csinh, csqrt, ctan, 9896 and ctanh. The float and long double variants of these functions 9897 (e.g. csinf and csinl) are also handled. 9898 * A new link-time optimizer has been added ([7]-flto). When this 9899 option is used, GCC generates a bytecode representation of each 9900 input file and writes it to specially-named sections in each object 9901 file. When the object files are linked together, all the function 9902 bodies are read from these named sections and instantiated as if 9903 they had been part of the same translation unit. This enables 9904 interprocedural optimizations to work across different files (and 9905 even different languages), potentially improving the performance of 9906 the generated code. To use the link-timer optimizer, -flto needs to 9907 be specified at compile time and during the final link. If the 9908 program does not require any symbols to be exported, it is possible 9909 to combine -flto and the experimental [8]-fwhopr with 9910 [9]-fwhole-program to allow the interprocedural optimizers to use 9911 more aggressive assumptions. 9912 * The automatic parallelization pass was enhanced to support 9913 parallelization of outer loops. 9914 * Automatic parallelization can be enabled as part of Graphite. In 9915 addition to -ftree-parallelize-loops=, specify 9916 -floop-parallelize-all to enable the Graphite-based optimization. 9917 * The infrastructure for optimizing based on [10]restrict qualified 9918 pointers has been rewritten and should result in code generation 9919 improvements. Optimizations based on restrict qualified pointers 9920 are now also available when using -fno-strict-aliasing. 9921 * There is a new optimization pass that attempts to change prototype 9922 of functions to avoid unused parameters, pass only relevant parts 9923 of structures and turn arguments passed by reference to arguments 9924 passed by value when possible. It is enabled by -O2 and above as 9925 well as -Os and can be manually invoked using the new command-line 9926 switch -fipa-sra. 9927 * GCC now optimize exception handling code. In particular cleanup 9928 regions that are proved to not have any effect are optimized out. 9929 9930 New Languages and Language specific improvements 9931 9932 All languages 9933 9934 * The -fshow-column option is now on by default. This means error 9935 messages now have a column associated with them. 9936 9937 Ada 9938 9939 * Compilation of programs heavily using discriminated record types 9940 with variant parts has been sped up and generates more compact 9941 code. 9942 * Stack checking now works reasonably well on most plaforms. In some 9943 specific cases, stack overflows may still fail to be detected, but 9944 a compile-time warning will be issued for these cases. 9945 9946 C family 9947 9948 * If a header named in a #include directive is not found, the 9949 compiler exits immediately. This avoids a cascade of errors arising 9950 from declarations expected to be found in that header being 9951 missing. 9952 * A new built-in function __builtin_unreachable() has been added that 9953 tells the compiler that control will never reach that point. It may 9954 be used after asm statements that terminate by transferring control 9955 elsewhere, and in other places that are known to be unreachable. 9956 * The -Wlogical-op option now warns for logical expressions such as 9957 (c == 1 && c == 2) and (c != 1 || c != 2), which are likely to be 9958 mistakes. This option is disabled by default. 9959 * An asm goto feature has been added to allow asm statements that 9960 jump to C labels. 9961 * C++0x raw strings are supported for C++ and for C with -std=gnu99. 9962 * The deprecated attribute now takes an optional string argument, for 9963 example, __attribute__((deprecated("text string"))), that will be 9964 printed together with the deprecation warning. 9965 9966 C 9967 9968 * The -Wenum-compare option, which warns when comparing values of 9969 different enum types, now works for C. It formerly only worked for 9970 C++. This warning is enabled by -Wall. It may be avoided by using a 9971 type cast. 9972 * The -Wcast-qual option now warns about casts which are unsafe in 9973 that they permit const-correctness to be violated without further 9974 warnings. Specifically, it warns about cases where a qualifier is 9975 added when all the lower types are not const. For example, it warns 9976 about a cast from char ** to const char **. 9977 * The -Wc++-compat option is significantly improved. It issues new 9978 warnings for: 9979 + Using C++ reserved operator names as identifiers. 9980 + Conversions to enum types without explicit casts. 9981 + Using va_arg with an enum type. 9982 + Using different enum types in the two branches of ?:. 9983 + Using ++ or -- on a variable of enum type. 9984 + Using the same name as both a struct, union or enum tag and a 9985 typedef, unless the typedef refers to the tagged type itself. 9986 + Using a struct, union, or enum which is defined within another 9987 struct or union. 9988 + A struct field defined using a typedef if there is a field in 9989 the struct, or an enclosing struct, whose name is the typedef 9990 name. 9991 + Duplicate definitions at file scope. 9992 + Uninitialized const variables. 9993 + A global variable with an anonymous struct, union, or enum 9994 type. 9995 + Using a string constant to initialize a char array whose size 9996 is the length of the string. 9997 * The new -Wjump-misses-init option warns about cases where a goto or 9998 switch skips the initialization of a variable. This sort of branch 9999 is an error in C++ but not in C. This warning is enabled by 10000 -Wc++-compat. 10001 * GCC now ensures that a C99-conforming <stdint.h> is present on most 10002 targets, and uses information about the types in this header to 10003 implement the Fortran bindings to those types. GCC does not ensure 10004 the presence of such a header, and does not implement the Fortran 10005 bindings, on the following targets: NetBSD, VxWorks, VMS, 10006 SymbianOS, WinCE, LynxOS, Netware, QNX, Interix, TPF. 10007 * GCC now implements C90- and C99-conforming rules for constant 10008 expressions. This may cause warnings or errors for some code using 10009 expressions that can be folded to a constant but are not constant 10010 expressions as defined by ISO C. 10011 * All known target-independent C90 and C90 Amendment 1 conformance 10012 bugs, and all known target-independent C99 conformance bugs not 10013 related to floating point or extended identifiers, have been fixed. 10014 * The C decimal floating point support now includes support for the 10015 FLOAT_CONST_DECIMAL64 pragma. 10016 * The named address space feature from ISO/IEC TR 18037 is now 10017 supported. This is currently only implemented for the SPU 10018 processor. 10019 10020 C++ 10021 10022 * Improved [11]experimental support for the upcoming C++0x ISO C++ 10023 standard, including support for raw strings, lambda expressions and 10024 explicit type conversion operators. 10025 * When printing the name of a class template specialization, G++ will 10026 now omit any template arguments which come from default template 10027 arguments. This behavior (and the pretty-printing of function 10028 template specializations as template signature and arguments) can 10029 be disabled with the -fno-pretty-templates option. 10030 * Access control is now applied to typedef names used in a template, 10031 which may cause G++ to reject some ill-formed code that was 10032 accepted by earlier releases. The -fno-access-control option can be 10033 used as a temporary workaround until the code is corrected. 10034 * Compilation time for code that uses templates should now scale 10035 linearly with the number of instantiations rather than 10036 quadratically, as template instantiations are now looked up using 10037 hash tables. 10038 * Declarations of functions that look like builtin declarations of 10039 library functions are only considered to be redeclarations if they 10040 are declared with extern "C". This may cause problems with code 10041 that omits extern "C" on hand-written declarations of C library 10042 functions such as abort or memcpy. Such code is ill-formed, but was 10043 accepted by earlier releases. 10044 * Diagnostics that used to complain about passing non-POD types to 10045 ... or jumping past the declaration of a non-POD variable now check 10046 for triviality rather than PODness, as per C++0x. 10047 * In C++0x mode local and anonymous classes are now allowed as 10048 template arguments, and in declarations of variables and functions 10049 with linkage, so long as any such declaration that is used is also 10050 defined ([12]DR 757). 10051 * Labels may now have attributes, as has been permitted for a while 10052 in C. This is only permitted when the label definition and the 10053 attribute specifier is followed by a semicoloni.e., the label 10054 applies to an empty statement. The only useful attribute for a 10055 label is unused. 10056 * G++ now implements [13]DR 176. Previously G++ did not support using 10057 the injected-class-name of a template base class as a type name, 10058 and lookup of the name found the declaration of the template in the 10059 enclosing scope. Now lookup of the name finds the 10060 injected-class-name, which can be used either as a type or as a 10061 template, depending on whether or not the name is followed by a 10062 template argument list. As a result of this change, some code that 10063 was previously accepted may be ill-formed because 10064 1. The injected-class-name is not accessible because it's from a 10065 private base, or 10066 2. The injected-class-name cannot be used as an argument for a 10067 template template parameter. 10068 In either of these cases, the code can be fixed by adding a 10069 nested-name-specifier to explicitly name the template. The first 10070 can be worked around with -fno-access-control; the second is only 10071 rejected with -pedantic. 10072 * A new standard mangling for SIMD vector types has been added, to 10073 avoid name clashes on systems with vectors of varying length. By 10074 default the compiler still uses the old mangling, but emits aliases 10075 with the new mangling on targets that support strong aliases. Users 10076 can switch over entirely to the new mangling with -fabi-version=4 10077 or -fabi-version=0. -Wabi will now warn about code that uses the 10078 old mangling. 10079 * The command-line option -ftemplate-depth-N is now written as 10080 -ftemplate-depth=N and the old form is deprecated. 10081 * Conversions between NULL and non-pointer types are now warned by 10082 default. The new option -Wno-conversion-null disables these 10083 warnings. Previously these warnings were only available when using 10084 -Wconversion explicitly. 10085 10086 Runtime Library (libstdc++) 10087 10088 * Improved experimental support for the upcoming ISO C++ standard, 10089 C++0x, including: 10090 + Support for <future>, <functional>, and <random>. 10091 + Existing facilities now exploit explicit operators and the 10092 newly implemented core C++0x features. 10093 + The header <cstdatomic> has been renamed to <atomic>. 10094 * An experimental [14]profile mode has been added. This is an 10095 implementation of many C++ standard library constructs with an 10096 additional analysis layer that gives performance improvement advice 10097 based on recognition of suboptimal usage patterns. For example, 10098 #include <vector> 10099 int main() 10100 { 10101 std::vector<int> v; 10102 for (int k = 0; k < 1024; ++k) 10103 v.insert(v.begin(), k); 10104 } 10105 10106 When instrumented via the profile mode, can return suggestions 10107 about the initial size and choice of the container used as follows: 10108 vector-to-list: improvement = 5: call stack = 0x804842c ... 10109 : advice = change std::vector to std::list 10110 vector-size: improvement = 3: call stack = 0x804842c ... 10111 : advice = change initial container size from 0 to 1024 10112 10113 These constructs can be substituted for the normal libstdc++ 10114 constructs on a piecemeal basis, or all existing components can be 10115 transformed via the -D_GLIBCXX_PROFILE macro. 10116 * [15]Support for decimal floating-point arithmetic (aka ISO C++ TR 10117 24733) has been added. This support is in header file 10118 <decimal/decimal>, uses namespace std::decimal, and includes 10119 classes decimal32, decimal64, and decimal128. 10120 * Sources have been audited for application of function attributes 10121 nothrow, const, pure, and noreturn. 10122 * Python pretty-printers have been added for many standard library 10123 components that simplify the internal representation and present a 10124 more intuitive view of components when used with 10125 appropriately-advanced versions of GDB. For more information, 10126 please consult the more [16]detailed description. 10127 * The default behavior for comparing typeinfo names has changed, so 10128 in <typeinfo>, __GXX_MERGED_TYPEINFO_NAMES now defaults to zero. 10129 * The new -static-libstdc++ option directs g++ to link the C++ 10130 library statically, even if the default would normally be to link 10131 it dynamically. 10132 10133 Fortran 10134 10135 * The COMMON default padding has been changed instead of adding the 10136 padding before a variable it is now added afterwards, which 10137 increases the compatibility with other vendors and helps to obtain 10138 the correct output in some cases. Cf. also the -falign-commons 10139 option ([17]added in 4.4). 10140 * The -finit-real= option now also supports the value snan for 10141 signaling not-a-number; to be effective, one additionally needs to 10142 enable trapping (e.g. via -ffpe-trap=). Note: Compile-time 10143 optimizations can turn a signaling NaN into a quiet one. 10144 * The new option -fcheck= has been added with the options bounds, 10145 array-temps, do, pointer, and recursive. The bounds and array-temps 10146 options are equivalent to -fbounds-check and 10147 -fcheck-array-temporaries. The do option checks for invalid 10148 modification of loop iteration variables, and the recursive option 10149 tests for recursive calls to subroutines/functions which are not 10150 marked as recursive. With pointer pointer association checks in 10151 calls are performed; however, neither undefined pointers nor 10152 pointers in expressions are handled. Using -fcheck=all enables all 10153 these run-time checks. 10154 * The run-time checking -fcheck=bounds now warns about invalid string 10155 lengths of character dummy arguments. Additionally, more 10156 compile-time checks have been added. 10157 * The new option [18]-fno-protect-parens has been added; if set, the 10158 compiler may reorder REAL and COMPLEX expressions without regard to 10159 parentheses. 10160 * GNU Fortran no longer links against libgfortranbegin. As before, 10161 MAIN__ (assembler symbol name) is the actual Fortran main program, 10162 which is invoked by the main function. However, main is now 10163 generated and put in the same object file as MAIN__. For the time 10164 being, libgfortranbegin still exists for backward compatibility. 10165 For details see the new [19]Mixed-Language Programming chapter in 10166 the manual. 10167 * The I/O library was restructured for performance and cleaner code. 10168 * Array assignments and WHERE are now run in parallel when OpenMP's 10169 WORKSHARE is used. 10170 * The experimental option -fwhole-file was added. The option allows 10171 whole-file checking of procedure arguments and allows for better 10172 optimizations. It can also be used with -fwhole-program, which is 10173 now also supported in gfortran. 10174 * More Fortran 2003 and Fortran 2008 mathematical functions can now 10175 be used as initialization expressions. 10176 * Some extended attributes such as STDCALL are now supported via the 10177 [20]GCC$ compiler directive. 10178 * For Fortran 77 compatibility: If -fno-sign-zero is used, the SIGN 10179 intrinsic behaves now as if zero were always positive. 10180 * For legacy compatibiliy: On Cygwin and MinGW, the special files 10181 CONOUT$ and CONIN$ (and CONERR$ which maps to CONOUT$) are now 10182 supported. 10183 * Fortran 2003 support has been extended: 10184 + Procedure-pointer function results and procedure-pointer 10185 components (including PASS), 10186 + allocatable scalars (experimental), 10187 + DEFERRED type-bound procedures, 10188 + the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements 10189 have been implemented. 10190 + The ALLOCATE statement supports type-specs and the SOURCE= 10191 argument. 10192 + OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC 10193 type-bound procedure (i.e. as type-bound operators). 10194 + Rounding (ROUND=, RZ, ...) for output is now supported. 10195 + The INT_FAST{8,16,32,64,128}_T kind type parameters of the 10196 intrinsic module ISO_C_BINDING are now supported, except for 10197 the targets listed above as ones where GCC does not have 10198 <stdint.h> type information. 10199 + Extensible derived types with type-bound procedure or 10200 procedure pointer with PASS attribute now have to use CLASS in 10201 line with the Fortran 2003 standard; the workaround to use 10202 TYPE is no longer supported. 10203 + [21]Experimental, incomplete support for polymorphism, 10204 including CLASS, SELECT TYPE and dynamic dispatch of 10205 type-bound procedure calls. Some features do not work yet such 10206 as unlimited polymorphism (CLASS(*)). 10207 * Fortran 2008 support has been extended: 10208 + The OPEN statement now supports the NEWUNIT= option, which 10209 returns a unique file unit, thus preventing inadvertent use of 10210 the same unit in different parts of the program. 10211 + Support for unlimited format items has been added. 10212 + The INT{8,16,32} and REAL{32,64,128} kind type parameters of 10213 the intrinsic module ISO_FORTRAN_ENV are now supported. 10214 + Using complex arguments with TAN, SINH, COSH, TANH, ASIN, 10215 ACOS, and ATAN is now possible; the functions ASINH, ACOSH, 10216 and ATANH have been added (for real and complex arguments) and 10217 ATAN(Y,X) is now an alias for ATAN2(Y,X). 10218 + The BLOCK construct has been implemented. 10219 10220 New Targets and Target Specific Improvements 10221 10222 AIX 10223 10224 * Full cross-toolchain support now available with GNU Binutils 10225 10226 ARM 10227 10228 * GCC now supports the Cortex-M0 and Cortex-A5 processors. 10229 * GCC now supports the ARM v7E-M architecture. 10230 * GCC now supports VFPv4-based FPUs and FPUs with 10231 single-precision-only VFP. 10232 * GCC has many improvements to optimization for other ARM processors, 10233 including scheduling support for the integer pipeline on Cortex-A9. 10234 * GCC now supports the IEEE 754-2008 half-precision floating-point 10235 type, and a variant ARM-specific half-precision type. This type is 10236 specified using __fp16, with the layout determined by 10237 -mfp16-format. With appropriate -mfpu options, the Cortex-A9 and 10238 VFPv4 half-precision instructions will be used. 10239 * GCC now supports the variant of AAPCS that uses VFP registers for 10240 parameter passing and return values. 10241 10242 AVR 10243 10244 * The -mno-tablejump option has been removed because it has the same 10245 effect as the -fno-jump-tables option. 10246 * Added support for these new AVR devices: 10247 + ATmega8U2 10248 + ATmega16U2 10249 + ATmega32U2 10250 10251 IA-32/x86-64 10252 10253 * GCC now will set the default for -march= based on the configure 10254 target. 10255 * GCC now supports handling floating-point excess precision arising 10256 from use of the x87 floating-point unit in a way that conforms to 10257 ISO C99. This is enabled with -fexcess-precision=standard and with 10258 standards conformance options such as -std=c99, and may be disabled 10259 using -fexcess-precision=fast. 10260 * Support for the Intel Atom processor is now available through the 10261 -march=atom and -mtune=atom options. 10262 * A new -mcrc32 option is now available to enable crc32 intrinsics. 10263 * A new -mmovbe option is now available to enable GCC to use the 10264 movbe instruction to implement __builtin_bswap32 and 10265 __builtin_bswap64. 10266 * SSE math now can be enabled by default at configure time with the 10267 new --with-fpmath=sse option. 10268 * There is a new intrinsic header file, <x86intrin.h>. It should be 10269 included before using any IA-32/x86-64 intrinsics. 10270 * Support for the XOP, FMA4, and LWP instruction sets for the AMD 10271 Orochi processors are now available with the -mxop, -mfma4, and 10272 -mlwp options. 10273 * The -mabm option enables GCC to use the popcnt and lzcnt 10274 instructions on AMD processors. 10275 * The -mpopcnt option enables GCC to use the popcnt instructions on 10276 both AMD and Intel processors. 10277 10278 M68K/ColdFire 10279 10280 * GCC now supports ColdFire 51xx, 5221x, 5225x, 52274, 52277, 5301x 10281 and 5441x devices. 10282 * GCC now supports thread-local storage (TLS) on M68K and ColdFire 10283 processors. 10284 10285 MeP 10286 10287 Support has been added for the Toshiba Media embedded Processor (MeP, 10288 or mep-elf) embedded target. 10289 10290 MIPS 10291 10292 * GCC now supports MIPS 1004K processors. 10293 * GCC can now be configured with options --with-arch-32, 10294 --with-arch-64, --with-tune-32 and --with-tune-64 to control the 10295 default optimization separately for 32-bit and 64-bit modes. 10296 * MIPS targets now support an alternative _mcount interface, in which 10297 register $12 points to the function's save slot for register $31. 10298 This interface is selected by the -mcount-ra-address option; see 10299 the documentation for more details. 10300 * GNU/Linux targets can now generate read-only .eh_frame sections. 10301 This optimization requires GNU binutils 2.20 or above, and is only 10302 available if GCC is configured with a suitable version of binutils. 10303 * GNU/Linux targets can now attach special relocations to indirect 10304 calls, so that the linker can turn them into direct jumps or 10305 branches. This optimization requires GNU binutils 2.20 or later, 10306 and is automatically selected if GCC is configured with an 10307 appropriate version of binutils. It can be explicitly enabled or 10308 disabled using the -mrelax-pic-calls command-line option. 10309 * GCC now generates more heavily-optimized atomic operations on 10310 Octeon processors. 10311 * MIPS targets now support the -fstack-protector option. 10312 * GCC now supports an -msynci option, which specifies that synci is 10313 enough to flush the instruction cache, without help from the 10314 operating system. GCC uses this information to optimize 10315 automatically-generated cache flush operations, such as those used 10316 for nested functions in C. There is also a --with-synci 10317 configure-time option, which makes -msynci the default. 10318 * GCC supports four new function attributes for interrupt handlers: 10319 interrupt, use_shadow_register_set, keep_interrupts_masked and 10320 use_debug_exception_return. See the documentation for more details 10321 about these attributes. 10322 10323 RS/6000 (POWER/PowerPC) 10324 10325 * GCC now supports the Power ISA 2.06, which includes the VSX 10326 instructions that add vector 64-bit floating point support, new 10327 population count instructions, and conversions between floating 10328 point and unsigned types. 10329 * Support for the power7 processor is now available through the 10330 -mcpu=power7 and -mtune=power7. 10331 * GCC will now vectorize loops that contain simple math functions 10332 like copysign when generating code for altivec or VSX targets. 10333 * Support for the A2 processor is now available through the -mcpu=a2 10334 and -mtune=a2 options. 10335 * Support for the 476 processor is now available through the 10336 -mcpu={476,476fp} and -mtune={476,476fp} options. 10337 * Support for the e500mc64 processor is now available through the 10338 -mcpu=e500mc64 and -mtune=e500mc64 options. 10339 * GCC can now be configured with options --with-cpu-32, 10340 --with-cpu-64, --with-tune-32 and --with-tune-64 to control the 10341 default optimization separately for 32-bit and 64-bit modes. 10342 * Starting with GCC 4.5.4, vectors of type vector long long or vector 10343 long are passed and returned in the same method as other vectors 10344 with the VSX instruction set. Previously the GCC compiler did not 10345 adhere to the ABI for 128-bit vectors with 64-bit integer base 10346 types (PR 48857). This is also fixed in the GCC 4.6.1 release. 10347 10348 RX 10349 10350 Support has been added for the Renesas RX Processor (rx-elf) target. 10351 10352 Operating Systems 10353 10354 Windows (Cygwin and MinGW) 10355 10356 * GCC now installs all the major language runtime libraries as DLLs 10357 when configured with the --enable-shared option. 10358 * GCC now makes use of the new support for aligned common variables 10359 in versions of binutils >= 2.20 to fix bugs in the support for SSE 10360 data types. 10361 * Improvements to the libffi support library increase the reliability 10362 of code generated by GCJ on all Windows platforms. Libgcj is 10363 enabled by default for the first time. 10364 * Libtool improvements simplify installation by placing the generated 10365 DLLs in the correct binaries directory. 10366 * Numerous other minor bugfixes and improvements, and substantial 10367 enhancements to the Fortran language support library. 10368 10369 > 10370 10371 Other significant improvements 10372 10373 Plugins 10374 10375 * It is now possible to extend the compiler without having to modify 10376 its source code. A new option -fplugin=file.so tells GCC to load 10377 the shared object file.so and execute it as part of the compiler. 10378 The internal documentation describes the details on how plugins can 10379 interact with the compiler. 10380 10381 Installation changes 10382 10383 * The move to newer autotools changed default installation 10384 directories and switches to control them: The --with-datarootdir, 10385 --with-docdir, --with-pdfdir, and --with-htmldir switches are not 10386 used any more. Instead, you can now use --datarootdir, --docdir, 10387 --htmldir, and --pdfdir. The default installation directories have 10388 changed as follows according to the GNU Coding Standards: 10389 10390 datarootdir read-only architecture-independent data root [PREFIX/share] 10391 localedir locale-specific message catalogs [DATAROOTDIR/locale] 10392 docdir documentation root [DATAROOTDIR/doc/PACKAGE] 10393 htmldir html documentation [DOCDIR] 10394 dvidir dvi documentation [DOCDIR] 10395 pdfdir pdf documentation [DOCDIR] 10396 psdir ps documentation [DOCDIR] 10397 The following variables have new default values: 10398 10399 datadir read-only architecture-independent data [DATAROOTDIR] 10400 infodir info documentation [DATAROOTDIR/info] 10401 mandir man documentation [DATAROOTDIR/man] 10402 10403 GCC 4.5.1 10404 10405 This is the [22]list of problem reports (PRs) from GCC's bug tracking 10406 system that are known to be fixed in the 4.5.1 release. This list might 10407 not be complete (that is, it is possible that some PRs that have been 10408 fixed are not listed here). 10409 10410 All languages 10411 10412 * GCC's new link-time optimizer ([23]-flto) now also works on a few 10413 non-ELF targets: 10414 + Cygwin (*-cygwin*) 10415 + MinGW (*-mingw*) 10416 + Darwin on x86-64 (x86_64-apple-darwin*) 10417 LTO is not enabled by default for these targets. To enable LTO, you 10418 should configure with the --enable-lto option. 10419 10420 GCC 4.5.2 10421 10422 This is the [24]list of problem reports (PRs) from GCC's bug tracking 10423 system that are known to be fixed in the 4.5.2 release. This list might 10424 not be complete (that is, it is possible that some PRs that have been 10425 fixed are not listed here). 10426 10427 GCC 4.5.3 10428 10429 This is the [25]list of problem reports (PRs) from GCC's bug tracking 10430 system that are known to be fixed in the 4.5.3 release. This list might 10431 not be complete (that is, it is possible that some PRs that have been 10432 fixed are not listed here). 10433 10434 On the PowerPC compiler, the Altivec builtin functions vec_ld and 10435 vec_st have been modified to generate the Altivec memory instructions 10436 LVX and STVX, even if the -mvsx option is used. In the initial GCC 4.5 10437 release, these builtin functions were changed to generate VSX memory 10438 reference instructions instead of Altivec memory instructions, but 10439 there are differences between the two instructions. If the VSX 10440 instruction set is available, you can now use the new builtin functions 10441 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 10442 instructions. 10443 10444 GCC 4.5.4 10445 10446 This is the [26]list of problem reports (PRs) from GCC's bug tracking 10447 system that are known to be fixed in the 4.5.4 release. This list might 10448 not be complete (that is, it is possible that some PRs that have been 10449 fixed are not listed here). 10450 10451 10452 For questions related to the use of GCC, please consult these web 10453 pages and the [27]GCC manuals. If that fails, the 10454 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10455 web pages and the development of GCC are welcome on our developer 10456 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 10457 archives. 10458 10459 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 10460 distribution of this entire article is permitted in any medium, 10461 provided this notice is preserved. 10462 10463 These pages are [32]maintained by the GCC team. Last modified 10464 2022-02-02[33]. 10465 10466 References 10467 10468 1. https://www.multiprecision.org/mpc/ 10469 2. https://gcc.gnu.org/install/prerequisites.html 10470 3. https://gcc.gnu.org/ml/gcc/2010-01/msg00510.html 10471 4. http://gcc.gnu.org/gcc-4.4/changes.html#obsoleted 10472 5. http://gcc.gnu.org/gcc-4.5/changes.html#x86 10473 6. https://gcc.gnu.org/PR30789 10474 7. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 10475 8. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhopr-802 10476 9. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhole-program-800 10477 10. https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html 10478 11. http://gcc.gnu.org/gcc-4.5/cxx0x_status.html 10479 12. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#757 10480 13. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#176 10481 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/profile_mode.html 10482 15. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.tr24733 10483 16. https://sourceware.org/gdb/wiki/STLSupport 10484 17. http://gcc.gnu.org/gcc-4.4/changes.html 10485 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 10486 19. https://gcc.gnu.org/onlinedocs/gfortran/Mixed-Language-Programming.html 10487 20. https://gcc.gnu.org/onlinedocs/gfortran/GNU-Fortran-Compiler-Directives.html 10488 21. https://gcc.gnu.org/wiki/OOP 10489 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.1 10490 23. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 10491 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.2 10492 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.3 10493 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.4 10494 27. https://gcc.gnu.org/onlinedocs/ 10495 28. mailto:gcc-help (a] gcc.gnu.org 10496 29. mailto:gcc (a] gcc.gnu.org 10497 30. https://gcc.gnu.org/lists.html 10498 31. https://www.fsf.org/ 10499 32. https://gcc.gnu.org/about.html 10500 33. http://validator.w3.org/check/referer 10501 ====================================================================== 10502 http://gcc.gnu.org/gcc-4.4/index.html 10503 GCC 4.4 Release Series 10504 10505 This release series is no longer maintained. 10506 10507 March 13, 2012 10508 10509 The [1]GNU project and the GCC developers are pleased to announce the 10510 release of GCC 4.4.7. 10511 10512 This release is a bug-fix release, containing fixes for regressions in 10513 GCC 4.4.6 relative to previous releases of GCC. 10514 10515 Release History 10516 10517 GCC 4.4.7 10518 March 13, 2012 ([2]changes) 10519 10520 GCC 4.4.6 10521 April 16, 2011 ([3]changes) 10522 10523 GCC 4.4.5 10524 October 1, 2010 ([4]changes) 10525 10526 GCC 4.4.4 10527 April 29, 2010 ([5]changes) 10528 10529 GCC 4.4.3 10530 January 21, 2010 ([6]changes) 10531 10532 GCC 4.4.2 10533 October 15, 2009 ([7]changes) 10534 10535 GCC 4.4.1 10536 July 22, 2009 ([8]changes) 10537 10538 GCC 4.4.0 10539 April 21, 2009 ([9]changes) 10540 10541 References and Acknowledgements 10542 10543 GCC used to stand for the GNU C Compiler, but since the compiler 10544 supports several other languages aside from C, it now stands for the 10545 GNU Compiler Collection. 10546 10547 A list of [10]successful builds is updated as new information becomes 10548 available. 10549 10550 The GCC developers would like to thank the numerous people that have 10551 contributed new features, improvements, bug fixes, and other changes as 10552 well as test results to GCC. This [11]amazing group of volunteers is 10553 what makes GCC successful. 10554 10555 For additional information about GCC please refer to the [12]GCC 10556 project web site or contact the [13]GCC development mailing list. 10557 10558 To obtain GCC please use [14]our mirror sites or [15]our version 10559 control system. 10560 10561 10562 For questions related to the use of GCC, please consult these web 10563 pages and the [16]GCC manuals. If that fails, the 10564 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10565 web pages and the development of GCC are welcome on our developer 10566 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 10567 archives. 10568 10569 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 10570 distribution of this entire article is permitted in any medium, 10571 provided this notice is preserved. 10572 10573 These pages are [21]maintained by the GCC team. Last modified 10574 2021-07-28[22]. 10575 10576 References 10577 10578 1. http://www.gnu.org/ 10579 2. http://gcc.gnu.org/gcc-4.4/changes.html 10580 3. http://gcc.gnu.org/gcc-4.4/changes.html 10581 4. http://gcc.gnu.org/gcc-4.4/changes.html 10582 5. http://gcc.gnu.org/gcc-4.4/changes.html 10583 6. http://gcc.gnu.org/gcc-4.4/changes.html 10584 7. http://gcc.gnu.org/gcc-4.4/changes.html 10585 8. http://gcc.gnu.org/gcc-4.4/changes.html 10586 9. http://gcc.gnu.org/gcc-4.4/changes.html 10587 10. http://gcc.gnu.org/gcc-4.4/buildstat.html 10588 11. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 10589 12. http://gcc.gnu.org/index.html 10590 13. mailto:gcc (a] gcc.gnu.org 10591 14. http://gcc.gnu.org/mirrors.html 10592 15. http://gcc.gnu.org/git.html 10593 16. https://gcc.gnu.org/onlinedocs/ 10594 17. mailto:gcc-help (a] gcc.gnu.org 10595 18. mailto:gcc (a] gcc.gnu.org 10596 19. https://gcc.gnu.org/lists.html 10597 20. https://www.fsf.org/ 10598 21. https://gcc.gnu.org/about.html 10599 22. http://validator.w3.org/check/referer 10600 ====================================================================== 10601 http://gcc.gnu.org/gcc-4.4/changes.html 10602 GCC 4.4 Release Series 10603 Changes, New Features, and Fixes 10604 10605 The latest release in the 4.4 release series is [1]GCC 4.4.7. 10606 10607 Caveats 10608 10609 * __builtin_stdarg_start has been completely removed from GCC. 10610 Support for <varargs.h> had been deprecated since GCC 4.0. Use 10611 __builtin_va_start as a replacement. 10612 * Some of the errors issued by the C++ front end that could be 10613 downgraded to warnings in previous releases by using -fpermissive 10614 are now warnings by default. They can be converted into errors by 10615 using -pedantic-errors. 10616 * Use of the cpp assertion extension will now emit a warning when 10617 -Wdeprecated or -pedantic is used. This extension has been 10618 deprecated for many years, but never warned about. 10619 * Packed bit-fields of type char were not properly bit-packed on many 10620 targets prior to GCC 4.4. On these targets, the fix in GCC 4.4 10621 causes an ABI change. For example there is no longer a 4-bit 10622 padding between field a and b in this structure: 10623 struct foo 10624 { 10625 char a:4; 10626 char b:8; 10627 } __attribute__ ((packed)); 10628 There is a new warning to help identify fields that are affected: 10629 foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4 10630 The warning can be disabled with -Wno-packed-bitfield-compat. 10631 * On ARM EABI targets, the C++ mangling of the va_list type has been 10632 changed to conform to the current revision of the EABI. This does 10633 not affect the libstdc++ library included with GCC. 10634 * The SCOUNT and POS bits of the MIPS DSP control register are now 10635 treated as global. Previous versions of GCC treated these fields as 10636 call-clobbered instead. 10637 * The MIPS port no longer recognizes the h asm constraint. It was 10638 necessary to remove this constraint in order to avoid generating 10639 unpredictable code sequences. 10640 One of the main uses of the h constraint was to extract the high 10641 part of a multiplication on 64-bit targets. For example: 10642 asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y)); 10643 You can now achieve the same effect using 128-bit types: 10644 typedef unsigned int uint128_t __attribute__((mode(TI))); 10645 result = ((uint128_t) x * y) >> 64; 10646 The second sequence is better in many ways. For example, if x and y 10647 are constants, the compiler can perform the multiplication at 10648 compile time. If x and y are not constants, the compiler can 10649 schedule the runtime multiplication better than it can schedule an 10650 asm statement. 10651 * Support for a number of older systems and recently unmaintained or 10652 untested target ports of GCC has been declared obsolete in GCC 4.4. 10653 Unless there is activity to revive them, the next release of GCC 10654 will have their sources permanently removed. 10655 The following ports for individual systems on particular 10656 architectures have been obsoleted: 10657 + Generic a.out on IA32 and m68k (i[34567]86-*-aout*, 10658 m68k-*-aout*) 10659 + Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*, 10660 armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*, 10661 sh-*-*). This does not affect other more specific targets 10662 using the COFF object format on those architectures, or the 10663 more specific H8300 and SH targets (h8300-*-rtems*, 10664 h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*, 10665 sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks). 10666 + 2BSD on PDP-11 (pdp11-*-bsd) 10667 + AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*, 10668 powerpc-ibm-aix4.[12]*) 10669 + Tuning support for Itanium1 (Merced) variants. Note that code 10670 tuned for Itanium2 should also run correctly on Itanium1. 10671 * The protoize and unprotoize utilities have been obsoleted and will 10672 be removed in GCC 4.5. These utilities have not been installed by 10673 default since GCC 3.0. 10674 * Support has been removed for all the [2]configurations obsoleted in 10675 GCC 4.3. 10676 * Unknown -Wno-* options are now silently ignored by GCC if no other 10677 diagnostics are issued. If other diagnostics are issued, then GCC 10678 warns about the unknown options. 10679 * More information on porting to GCC 4.4 from previous versions of 10680 GCC can be found in the [3]porting guide for this release. 10681 10682 General Optimizer Improvements 10683 10684 * A new command-line switch -findirect-inlining has been added. When 10685 turned on it allows the inliner to also inline indirect calls that 10686 are discovered to have known targets at compile time thanks to 10687 previous inlining. 10688 * A new command-line switch -ftree-switch-conversion has been added. 10689 This new pass turns simple initializations of scalar variables in 10690 switch statements into initializations from a static array, given 10691 that all the values are known at compile time and the ratio between 10692 the new array size and the original switch branches does not exceed 10693 the parameter --param switch-conversion-max-branch-ratio (default 10694 is eight). 10695 * A new command-line switch -ftree-builtin-call-dce has been added. 10696 This optimization eliminates unnecessary calls to certain builtin 10697 functions when the return value is not used, in cases where the 10698 calls can not be eliminated entirely because the function may set 10699 errno. This optimization is on by default at -O2 and above. 10700 * A new command-line switch -fconserve-stack directs the compiler to 10701 minimize stack usage even if it makes the generated code slower. 10702 This affects inlining decisions. 10703 * When the assembler supports it, the compiler will now emit unwind 10704 information using assembler .cfi directives. This makes it possible 10705 to use such directives in inline assembler code. The new option 10706 -fno-dwarf2-cfi-asm directs the compiler to not use .cfi 10707 directives. 10708 * The [4]Graphite branch has been merged. This merge has brought in a 10709 new framework for loop optimizations based on a polyhedral 10710 intermediate representation. These optimizations apply to all the 10711 languages supported by GCC. The following new code transformations 10712 are available in GCC 4.4: 10713 + -floop-interchange performs loop interchange transformations 10714 on loops. Interchanging two nested loops switches the inner 10715 and outer loops. For example, given a loop like: 10716 DO J = 1, M 10717 DO I = 1, N 10718 A(J, I) = A(J, I) * C 10719 ENDDO 10720 ENDDO 10721 10722 loop interchange will transform the loop as if the user had 10723 written: 10724 DO I = 1, N 10725 DO J = 1, M 10726 A(J, I) = A(J, I) * C 10727 ENDDO 10728 ENDDO 10729 10730 which can be beneficial when N is larger than the caches, 10731 because in Fortran, the elements of an array are stored in 10732 memory contiguously by column, and the original loop iterates 10733 over rows, potentially creating at each access a cache miss. 10734 + -floop-strip-mine performs loop strip mining transformations 10735 on loops. Strip mining splits a loop into two nested loops. 10736 The outer loop has strides equal to the strip size and the 10737 inner loop has strides of the original loop within a strip. 10738 For example, given a loop like: 10739 DO I = 1, N 10740 A(I) = A(I) + C 10741 ENDDO 10742 10743 loop strip mining will transform the loop as if the user had 10744 written: 10745 DO II = 1, N, 4 10746 DO I = II, min (II + 3, N) 10747 A(I) = A(I) + C 10748 ENDDO 10749 ENDDO 10750 10751 + -floop-block performs loop blocking transformations on loops. 10752 Blocking strip mines each loop in the loop nest such that the 10753 memory accesses of the element loops fit inside caches. For 10754 example, given a loop like: 10755 DO I = 1, N 10756 DO J = 1, M 10757 A(J, I) = B(I) + C(J) 10758 ENDDO 10759 ENDDO 10760 10761 loop blocking will transform the loop as if the user had 10762 written: 10763 DO II = 1, N, 64 10764 DO JJ = 1, M, 64 10765 DO I = II, min (II + 63, N) 10766 DO J = JJ, min (JJ + 63, M) 10767 A(J, I) = B(I) + C(J) 10768 ENDDO 10769 ENDDO 10770 ENDDO 10771 ENDDO 10772 10773 which can be beneficial when M is larger than the caches, 10774 because the innermost loop will iterate over a smaller amount 10775 of data that can be kept in the caches. 10776 * A new register allocator has replaced the old one. It is called 10777 integrated register allocator (IRA) because coalescing, register 10778 live range splitting, and hard register preferencing are done 10779 on-the-fly during coloring. It also has better integration with the 10780 reload pass. IRA is a regional register allocator which uses modern 10781 Chaitin-Briggs coloring instead of Chow's priority coloring used in 10782 the old register allocator. More info about IRA internals and 10783 options can be found in the GCC manuals. 10784 * A new instruction scheduler and software pipeliner, based on the 10785 selective scheduling approach, has been added. The new pass 10786 performs instruction unification, register renaming, substitution 10787 through register copies, and speculation during scheduling. The 10788 software pipeliner is able to pipeline non-countable loops. The new 10789 pass is targeted at scheduling-eager in-order platforms. In GCC 4.4 10790 it is available for the Intel Itanium platform working by default 10791 as the second scheduling pass (after register allocation) at the 10792 -O3 optimization level. 10793 * When using -fprofile-generate with a multi-threaded program, the 10794 profile counts may be slightly wrong due to race conditions. The 10795 new -fprofile-correction option directs the compiler to apply 10796 heuristics to smooth out the inconsistencies. By default the 10797 compiler will give an error message when it finds an inconsistent 10798 profile. 10799 * The new -fprofile-dir=PATH option permits setting the directory 10800 where profile data files are stored when using -fprofile-generate 10801 and friends, and the directory used when reading profile data files 10802 using -fprofile-use and friends. 10803 10804 New warning options 10805 10806 * The new -Wframe-larger-than=NUMBER option directs GCC to emit a 10807 warning if any stack frame is larger than NUMBER bytes. This may be 10808 used to help ensure that code fits within a limited amount of stack 10809 space. 10810 * The command-line option -Wlarger-than-N is now written as 10811 -Wlarger-than=N and the old form is deprecated. 10812 * The new -Wno-mudflap option disables warnings about constructs 10813 which can not be instrumented when using -fmudflap. 10814 10815 New Languages and Language specific improvements 10816 10817 * Version 3.0 of the OpenMP specification is now supported for the C, 10818 C++, and Fortran compilers. 10819 * New character data types, per [5]TR 19769: New character types in 10820 C, are now supported for the C compiler in -std=gnu99 mode, as 10821 __CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in 10822 -std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too. 10823 10824 C family 10825 10826 * A new optimize attribute was added to allow programmers to change 10827 the optimization level and particular optimization options for an 10828 individual function. You can also change the optimization options 10829 via the GCC optimize pragma for functions defined after the pragma. 10830 The GCC push_options pragma and the GCC pop_options pragma allow 10831 you temporarily save and restore the options used. The GCC 10832 reset_options pragma restores the options to what was specified on 10833 the command line. 10834 * Uninitialized warnings do not require enabling optimization 10835 anymore, that is, -Wuninitialized can be used together with -O0. 10836 Nonetheless, the warnings given by -Wuninitialized will probably be 10837 more accurate if optimization is enabled. 10838 * -Wparentheses now warns about expressions such as (!x | y) and (!x 10839 & y). Using explicit parentheses, such as in ((!x) | y), silences 10840 this warning. 10841 * -Wsequence-point now warns within if, while,do while and for 10842 conditions, and within for begin/end expressions. 10843 * A new option -dU is available to dump definitions of preprocessor 10844 macros that are tested or expanded. 10845 10846 C++ 10847 10848 * [6]Improved experimental support for the upcoming ISO C++ standard, 10849 C++0x. Including support for auto, inline namespaces, generalized 10850 initializer lists, defaulted and deleted functions, new character 10851 types, and scoped enums. 10852 * Those errors that may be downgraded to warnings to build legacy 10853 code now mention -fpermissive when -fdiagnostics-show-option is 10854 enabled. 10855 * -Wconversion now warns if the result of a static_cast to enumeral 10856 type is unspecified because the value is outside the range of the 10857 enumeral type. 10858 * -Wuninitialized now warns if a non-static reference or non-static 10859 const member appears in a class without constructors. 10860 * G++ now properly implements value-initialization, so objects with 10861 an initializer of () and an implicitly defined default constructor 10862 will be zero-initialized before the default constructor is called. 10863 10864 Runtime Library (libstdc++) 10865 10866 * Improved experimental support for the upcoming ISO C++ standard, 10867 C++0x, including: 10868 + Support for <chrono>, <condition_variable>, <cstdatomic>, 10869 <forward_list>, <initializer_list>, <mutex>, <ratio>, 10870 <system_error>, and <thread>. 10871 + unique_ptr, <algorithm> additions, exception propagation, and 10872 support for the new character types in <string> and <limits>. 10873 + Existing facilities now exploit initializer lists, defaulted 10874 and deleted functions, and the newly implemented core C++0x 10875 features. 10876 + Some standard containers are more efficient together with 10877 stateful allocators, i.e., no allocator is constructed on the 10878 fly at element construction time. 10879 * Experimental support for non-standard pointer types in containers. 10880 * The long standing libstdc++/30928 has been fixed for targets 10881 running glibc 2.10 or later. 10882 * As usual, many small and larger bug fixes, in particular quite a 10883 few corner cases in <locale>. 10884 10885 Fortran 10886 10887 * GNU Fortran now employs libcpp directly instead of using cc1 as an 10888 external preprocessor. The [7]-cpp option was added to allow manual 10889 invocation of the preprocessor without relying on filename 10890 extensions. 10891 * The [8]-Warray-temporaries option warns about array temporaries 10892 generated by the compiler, as an aid to optimization. 10893 * The [9]-fcheck-array-temporaries option has been added, printing a 10894 notification at run time, when an array temporary had to be created 10895 for an function argument. Contrary to -Warray-temporaries the 10896 warning is only printed if the array is noncontiguous. 10897 * Improved generation of DWARF debugging symbols 10898 * If using an intrinsic not part of the selected standard (via -std= 10899 and -fall-intrinsics) gfortran will now treat it as if this 10900 procedure were declared EXTERNAL and try to link to a user-supplied 10901 procedure. -Wintrinsics-std will warn whenever this happens. The 10902 now-useless option -Wnonstd-intrinsic was removed. 10903 * The flag -falign-commons has been added to control the alignment of 10904 variables in COMMON blocks, which is enabled by default in line 10905 with previous GCC version. Using -fno-align-commons one can force 10906 commons to be contiguous in memory as required by the Fortran 10907 standard, however, this slows down the memory access. The option 10908 -Walign-commons, which is enabled by default, warns when padding 10909 bytes were added for alignment. The proper solution is to sort the 10910 common objects by decreasing storage size, which avoids the 10911 alignment problems. 10912 * Fortran 2003 support has been extended: 10913 + Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is 10914 now supported (except internal reads from/writes to wide 10915 strings). [10]-fbackslash now supports also \unnnn and 10916 \Unnnnnnnn to enter Unicode characters. 10917 + Asynchronous I/O (implemented as synchronous I/O) and the 10918 decimal=, size=, sign=, pad=, blank=, and delim= specifiers 10919 are now supported in I/O statements. 10920 + Support for Fortran 2003 structure constructors and for array 10921 constructor with typespec has been added. 10922 + Procedure Pointers (but not yet as component in derived types 10923 and as function results) are now supported. 10924 + Abstract types, type extension, and type-bound procedures 10925 (both PROCEDURE and GENERIC but not as operators). Note: As 10926 CLASS/polymorphyic types are not implemented, type-bound 10927 procedures with PASS accept as non-standard extension TYPE 10928 arguments. 10929 * Fortran 2008 support has been added: 10930 + The -std=f2008 option and support for the file extensions 10931 .f2008 and .F2008 has been added. 10932 + The g0 format descriptor is now supported. 10933 + The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH, 10934 ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED 10935 are now available (some of them existed as GNU extension 10936 before). Note: The hyperbolic functions are not yet supporting 10937 complex arguments and the three- argument version of BESSEL_*N 10938 is not available. 10939 + The bit intrinsics LEADZ and TRAILZ have been added. 10940 10941 Java (GCJ) 10942 10943 Ada 10944 10945 * The Ada runtime now supports multilibs on many platforms including 10946 x86_64, SPARC and PowerPC. Their build is enabled by default. 10947 10948 New Targets and Target Specific Improvements 10949 10950 ARM 10951 10952 * GCC now supports optimizing for the Cortex-A9, Cortex-R4 and 10953 Cortex-R4F processors and has many other improvements to 10954 optimization for ARM processors. 10955 * GCC now supports the VFPv3 variant with 16 double-precision 10956 registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been 10957 renamed to -mfpu=vfpv3. 10958 * GCC now supports the -mfix-cortex-m3-ldrd option to work around an 10959 erratum on Cortex-M3 processors. 10960 * GCC now supports the __sync_* atomic operations for ARM EABI 10961 GNU/Linux. 10962 * The section anchors optimization is now enabled by default when 10963 optimizing for ARM. 10964 * GCC now uses a new EABI-compatible profiling interface for EABI 10965 targets. This requires a function __gnu_mcount_nc, which is 10966 provided by GNU libc versions 2.8 and later. 10967 10968 AVR 10969 10970 * The -mno-tablejump option has been deprecated because it has the 10971 same effect as the -fno-jump-tables option. 10972 * Added support for these new AVR devices: 10973 + ATA6289 10974 + ATtiny13A 10975 + ATtiny87 10976 + ATtiny167 10977 + ATtiny327 10978 + ATmega8C1 10979 + ATmega16C1 10980 + ATmega32C1 10981 + ATmega8M1 10982 + ATmega16M1 10983 + ATmega32M1 10984 + ATmega32U4 10985 + ATmega16HVB 10986 + ATmega4HVD 10987 + ATmega8HVD 10988 + ATmega64C1 10989 + ATmega64M1 10990 + ATmega16U4 10991 + ATmega32U6 10992 + ATmega128RFA1 10993 + AT90PWM81 10994 + AT90SCR100 10995 + M3000F 10996 + M3000S 10997 + M3001B 10998 10999 IA-32/x86-64 11000 11001 * Support for Intel AES built-in functions and code generation is 11002 available via -maes. 11003 * Support for Intel PCLMUL built-in function and code generation is 11004 available via -mpclmul. 11005 * Support for Intel AVX built-in functions and code generation is 11006 available via -mavx. 11007 * Automatically align the stack for local variables with alignment 11008 requirement. 11009 * GCC can now utilize the SVML library for vectorizing calls to a set 11010 of C99 functions if -mveclibabi=svml is specified and you link to 11011 an SVML ABI compatible library. 11012 * On x86-64, the ABI has been changed in the following cases to 11013 conform to the x86-64 ABI: 11014 + Passing/returning structures with flexible array member: 11015 struct foo 11016 { 11017 int i; 11018 int flex[]; 11019 }; 11020 + Passing/returning structures with complex float member: 11021 struct foo 11022 { 11023 int i; 11024 __complex__ float f; 11025 }; 11026 + Passing/returning unions with long double member: 11027 union foo 11028 { 11029 int x; 11030 long double ld; 11031 }; 11032 Code built with previous versions of GCC that uses any of these is 11033 not compatible with code built with GCC 4.4.0 or later. 11034 * A new target attribute was added to allow programmers to change the 11035 target options like -msse2 or -march=k8 for an individual function. 11036 You can also change the target options via the GCC target pragma 11037 for functions defined after the pragma. 11038 * GCC can now be configured with options --with-arch-32, 11039 --with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and 11040 --with-tune-64 to control the default optimization separately for 11041 32-bit and 64-bit modes. 11042 11043 IA-32/IA64 11044 11045 * Support for __float128 (TFmode) IEEE quad type and corresponding 11046 TCmode IEEE complex quad type is available via the soft-fp library 11047 on IA-32/IA64 targets. This includes basic arithmetic operations 11048 (addition, subtraction, negation, multiplication and division) on 11049 __float128 real and TCmode complex values, the full set of IEEE 11050 comparisons between __float128 values, conversions to and from 11051 float, double and long double floating point types, as well as 11052 conversions to and from signed or unsigned integer, signed or 11053 unsigned long integer and signed or unsigned quad (TImode, IA64 11054 only) integer types. Additionally, all operations generate the full 11055 set of IEEE exceptions and support the full set of IEEE rounding 11056 modes. 11057 11058 M68K/ColdFire 11059 11060 * GCC now supports instruction scheduling for ColdFire V1, V3 and V4 11061 processors. (Scheduling support for ColdFire V2 processors was 11062 added in GCC 4.3.) 11063 * GCC now supports the -mxgot option to support programs requiring 11064 many GOT entries on ColdFire. 11065 * The m68k-*-linux-gnu target now builds multilibs by default. 11066 11067 MIPS 11068 11069 * MIPS Technologies have extended the original MIPS SVR4 ABI to 11070 include support for procedure linkage tables (PLTs) and copy 11071 relocations. These extensions allow GNU/Linux executables to use a 11072 significantly more efficient code model than the one defined by the 11073 original ABI. 11074 GCC support for this code model is available via a new command-line 11075 option, -mplt. There is also a new configure-time option, 11076 --with-mips-plt, to make -mplt the default. 11077 The new code model requires support from the assembler, the linker, 11078 and the runtime C library. This support is available in binutils 11079 2.19 and GLIBC 2.9. 11080 * GCC can now generate MIPS16 code for 32-bit GNU/Linux executables 11081 and 32-bit GNU/Linux shared libraries. This feature requires GNU 11082 binutils 2.19 or above. 11083 * Support for RMI's XLR processor is now available through the 11084 -march=xlr and -mtune=xlr options. 11085 * 64-bit targets can now perform 128-bit multiplications inline, 11086 instead of relying on a libgcc function. 11087 * Native GNU/Linux toolchains now support -march=native and 11088 -mtune=native, which select the host processor. 11089 * GCC now supports the R10K, R12K, R14K and R16K processors. The 11090 canonical -march= and -mtune= names for these processors are 11091 r10000, r12000, r14000 and r16000 respectively. 11092 * GCC can now work around the side effects of speculative execution 11093 on R10K processors. Please see the documentation of the 11094 -mr10k-cache-barrier option for details. 11095 * Support for the MIPS64 Release 2 instruction set has been added. 11096 The option -march=mips64r2 enables generation of these 11097 instructions. 11098 * GCC now supports Cavium Networks' Octeon processor. This support is 11099 available through the -march=octeon and -mtune=octeon options. 11100 * GCC now supports STMicroelectronics' Loongson 2E/2F processors. The 11101 canonical -march= and -mtune= names for these processors are 11102 loongson2e and loongson2f. 11103 11104 picochip 11105 11106 Picochip is a 16-bit processor. A typical picoChip contains over 250 11107 small cores, each with small amounts of memory. There are three 11108 processor variants (STAN, MEM and CTRL) with different instruction sets 11109 and memory configurations and they can be chosen using the -mae option. 11110 11111 This port is intended to be a "C" only port. 11112 11113 Power Architecture and PowerPC 11114 11115 * GCC now supports the e300c2, e300c3 and e500mc processors. 11116 * GCC now supports Xilinx processors with a single-precision FPU. 11117 * Decimal floating point is now supported for e500 processors. 11118 11119 S/390, zSeries and System z9/z10 11120 11121 * Support for the IBM System z10 EC/BC processor has been added. When 11122 using the -march=z10 option, the compiler will generate code making 11123 use of instructions provided by the General-Instruction-Extension 11124 Facility and the Execute-Extension Facility. 11125 11126 VxWorks 11127 11128 * GCC now supports the thread-local storage mechanism used on 11129 VxWorks. 11130 11131 Xtensa 11132 11133 * GCC now supports thread-local storage (TLS) for Xtensa processor 11134 configurations that include the Thread Pointer option. TLS also 11135 requires support from the assembler and linker; this support is 11136 provided in the GNU binutils beginning with version 2.19. 11137 11138 Documentation improvements 11139 11140 Other significant improvements 11141 11142 GCC 4.4.1 11143 11144 This is the [11]list of problem reports (PRs) from GCC's bug tracking 11145 system that are known to be fixed in the 4.4.1 release. This list might 11146 not be complete (that is, it is possible that some PRs that have been 11147 fixed are not listed here). 11148 11149 GCC 4.4.2 11150 11151 This is the [12]list of problem reports (PRs) from GCC's bug tracking 11152 system that are known to be fixed in the 4.4.2 release. This list might 11153 not be complete (that is, it is possible that some PRs that have been 11154 fixed are not listed here). 11155 11156 GCC 4.4.3 11157 11158 This is the [13]list of problem reports (PRs) from GCC's bug tracking 11159 system that are known to be fixed in the 4.4.3 release. This list might 11160 not be complete (that is, it is possible that some PRs that have been 11161 fixed are not listed here). 11162 11163 GCC 4.4.4 11164 11165 This is the [14]list of problem reports (PRs) from GCC's bug tracking 11166 system that are known to be fixed in the 4.4.4 release. This list might 11167 not be complete (that is, it is possible that some PRs that have been 11168 fixed are not listed here). 11169 11170 GCC 4.4.5 11171 11172 This is the [15]list of problem reports (PRs) from GCC's bug tracking 11173 system that are known to be fixed in the 4.4.5 release. This list might 11174 not be complete (that is, it is possible that some PRs that have been 11175 fixed are not listed here). 11176 11177 GCC 4.4.6 11178 11179 This is the [16]list of problem reports (PRs) from GCC's bug tracking 11180 system that are known to be fixed in the 4.4.6 release. This list might 11181 not be complete (that is, it is possible that some PRs that have been 11182 fixed are not listed here). 11183 11184 GCC 4.4.7 11185 11186 This is the [17]list of problem reports (PRs) from GCC's bug tracking 11187 system that are known to be fixed in the 4.4.7 release. This list might 11188 not be complete (that is, it is possible that some PRs that have been 11189 fixed are not listed here). 11190 11191 11192 For questions related to the use of GCC, please consult these web 11193 pages and the [18]GCC manuals. If that fails, the 11194 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11195 web pages and the development of GCC are welcome on our developer 11196 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 11197 archives. 11198 11199 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 11200 distribution of this entire article is permitted in any medium, 11201 provided this notice is preserved. 11202 11203 These pages are [23]maintained by the GCC team. Last modified 11204 2021-07-28[24]. 11205 11206 References 11207 11208 1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.7 11209 2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted 11210 3. http://gcc.gnu.org/gcc-4.4/porting_to.html 11211 4. https://gcc.gnu.org/wiki/Graphite 11212 5. http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf 11213 6. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html 11214 7. https://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html 11215 8. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125 11216 9. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221 11217 10. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34 11218 11. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1 11219 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2 11220 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3 11221 14. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4 11222 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.5 11223 16. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.6 11224 17. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.7 11225 18. https://gcc.gnu.org/onlinedocs/ 11226 19. mailto:gcc-help (a] gcc.gnu.org 11227 20. mailto:gcc (a] gcc.gnu.org 11228 21. https://gcc.gnu.org/lists.html 11229 22. https://www.fsf.org/ 11230 23. https://gcc.gnu.org/about.html 11231 24. http://validator.w3.org/check/referer 11232 ====================================================================== 11233 http://gcc.gnu.org/gcc-4.3/index.html 11234 GCC 4.3 Release Series 11235 11236 (This release series is no longer supported.) 11237 11238 Jun 27, 2011 11239 11240 The [1]GNU project and the GCC developers are pleased to announce the 11241 release of GCC 4.3.6. 11242 11243 This release is a bug-fix release, containing fixes for regressions in 11244 GCC 4.3.5 relative to previous releases of GCC. 11245 11246 Release History 11247 11248 GCC 4.3.6 11249 Jun 27, 2011 ([2]changes) 11250 11251 GCC 4.3.5 11252 May 22, 2010 ([3]changes) 11253 11254 GCC 4.3.4 11255 August 4, 2009 ([4]changes) 11256 11257 GCC 4.3.3 11258 January 24, 2009 ([5]changes) 11259 11260 GCC 4.3.2 11261 August 27, 2008 ([6]changes) 11262 11263 GCC 4.3.1 11264 June 6, 2008 ([7]changes) 11265 11266 GCC 4.3.0 11267 March 5, 2008 ([8]changes) 11268 11269 References and Acknowledgements 11270 11271 GCC used to stand for the GNU C Compiler, but since the compiler 11272 supports several other languages aside from C, it now stands for the 11273 GNU Compiler Collection. 11274 11275 A list of [9]successful builds is updated as new information becomes 11276 available. 11277 11278 The GCC developers would like to thank the numerous people that have 11279 contributed new features, improvements, bug fixes, and other changes as 11280 well as test results to GCC. This [10]amazing group of volunteers is 11281 what makes GCC successful. 11282 11283 For additional information about GCC please refer to the [11]GCC 11284 project web site or contact the [12]GCC development mailing list. 11285 11286 To obtain GCC please use [13]our mirror sites or [14]our version 11287 control system. 11288 11289 11290 For questions related to the use of GCC, please consult these web 11291 pages and the [15]GCC manuals. If that fails, the 11292 [16]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11293 web pages and the development of GCC are welcome on our developer 11294 list at [17]gcc (a] gcc.gnu.org. All of [18]our lists have public 11295 archives. 11296 11297 Copyright (C) [19]Free Software Foundation, Inc. Verbatim copying and 11298 distribution of this entire article is permitted in any medium, 11299 provided this notice is preserved. 11300 11301 These pages are [20]maintained by the GCC team. Last modified 11302 2021-07-28[21]. 11303 11304 References 11305 11306 1. http://www.gnu.org/ 11307 2. http://gcc.gnu.org/gcc-4.3/changes.html 11308 3. http://gcc.gnu.org/gcc-4.3/changes.html 11309 4. http://gcc.gnu.org/gcc-4.3/changes.html 11310 5. http://gcc.gnu.org/gcc-4.3/changes.html 11311 6. http://gcc.gnu.org/gcc-4.3/changes.html 11312 7. http://gcc.gnu.org/gcc-4.3/changes.html 11313 8. http://gcc.gnu.org/gcc-4.3/changes.html 11314 9. http://gcc.gnu.org/gcc-4.3/buildstat.html 11315 10. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 11316 11. http://gcc.gnu.org/index.html 11317 12. mailto:gcc (a] gcc.gnu.org 11318 13. http://gcc.gnu.org/mirrors.html 11319 14. http://gcc.gnu.org/git.html 11320 15. https://gcc.gnu.org/onlinedocs/ 11321 16. mailto:gcc-help (a] gcc.gnu.org 11322 17. mailto:gcc (a] gcc.gnu.org 11323 18. https://gcc.gnu.org/lists.html 11324 19. https://www.fsf.org/ 11325 20. https://gcc.gnu.org/about.html 11326 21. http://validator.w3.org/check/referer 11327 ====================================================================== 11328 http://gcc.gnu.org/gcc-4.3/changes.html 11329 GCC 4.3 Release Series 11330 Changes, New Features, and Fixes 11331 11332 The latest release in the 4.3 release series is [1]GCC 4.3.5. 11333 11334 Caveats 11335 11336 * GCC requires the [2]GMP and [3]MPFR libraries for building all the 11337 various front-end languages it supports. See the [4]prerequisites 11338 page for version requirements. 11339 * ColdFire targets now treat long double as having the same format as 11340 double. In earlier versions of GCC, they used the 68881 long double 11341 format instead. 11342 * The m68k-uclinux target now uses the same calling conventions as 11343 m68k-linux-gnu. You can select the original calling conventions by 11344 configuring for m68k-uclinuxoldabi instead. Note that 11345 m68k-uclinuxoldabi also retains the original 80-bit long double on 11346 ColdFire targets. 11347 * The -fforce-mem option has been removed because it has had no 11348 effect in the last few GCC releases. 11349 * The i386 -msvr3-shlib option has been removed since it is no longer 11350 used. 11351 * Fastcall for i386 has been changed not to pass aggregate arguments 11352 in registers, following Microsoft compilers. 11353 * Support for the AOF assembler has been removed from the ARM back 11354 end; this affects only the targets arm-semi-aof and armel-semi-aof, 11355 which are no longer recognized. We removed these targets without a 11356 deprecation period because we discovered that they have been 11357 unusable since GCC 4.0.0. 11358 * Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*) 11359 has been removed. This support had been deprecated since GCC 4.0.0. 11360 * Support for a number of older systems and recently unmaintained or 11361 untested target ports of GCC has been declared obsolete in GCC 4.3. 11362 Unless there is activity to revive them, the next release of GCC 11363 will have their sources permanently removed. 11364 All GCC ports for the following processor architectures have been 11365 declared obsolete: 11366 + Morpho MT (mt-*) 11367 The following aliases for processor architectures have been 11368 declared obsolete. Users should use the indicated generic target 11369 names instead, with compile-time options such as -mcpu or 11370 configure-time options such as --with-cpu to control the 11371 configuration more precisely. 11372 + strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-* 11373 instead). 11374 + parisc*-*-* (use hppa*-*-* instead). 11375 + m680[012]0-*-* (use m68k-*-* instead). 11376 All GCC ports for the following operating systems have been 11377 declared obsolete: 11378 + BeOS (*-*-beos*) 11379 + kaOS (*-*-kaos*) 11380 + GNU/Linux using the a.out object format (*-*-linux*aout*) 11381 + GNU/Linux using version 1 of the GNU C Library 11382 (*-*-linux*libc1*) 11383 + Solaris versions before Solaris 7 (*-*-solaris2.[0-6], 11384 *-*-solaris2.[0-6].*) 11385 + Miscellaneous System V (*-*-sysv*) 11386 + WindISS (*-*-windiss*) 11387 Also, those for some individual systems on particular architectures 11388 have been obsoleted: 11389 + UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*) 11390 + CRIS with a.out object format (cris-*-aout) 11391 + BSD 4.3 on PA-RISC (hppa1.1-*-bsd*) 11392 + OSF/1 on PA-RISC (hppa1.1-*-osf*) 11393 + PRO on PA-RISC (hppa1.1-*-pro*) 11394 + Sequent PTX on IA32 (i[34567]86-sequent-ptx4*, 11395 i[34567]86-sequent-sysv4*) 11396 + SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*) 11397 + UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host 11398 was previously [5]removed in 2001, leaving only the support 11399 for UWIN as a target now being deprecated) 11400 + ChorusOS on PowerPC (powerpc-*-chorusos*) 11401 + All VAX configurations apart from NetBSD and OpenBSD 11402 (vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*) 11403 * The [6]-Wconversion option has been modified. Its purpose now is to 11404 warn for implicit conversions that may alter a value. This new 11405 behavior is available for both C and C++. Warnings about 11406 conversions between signed and unsigned integers can be disabled by 11407 using -Wno-sign-conversion. In C++, they are disabled by default 11408 unless -Wsign-conversion is explicitly requested. The old behavior 11409 of -Wconversion, that is, warn for prototypes causing a type 11410 conversion that is different from what would happen to the same 11411 argument in the absence of a prototype, has been moved to a new 11412 option -Wtraditional-conversion, which is only available for C. 11413 * The -m386, -m486, -mpentium and -mpentiumpro tuning options have 11414 been removed because they were deprecated for more than 3 GCC major 11415 releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or 11416 -mtune=pentiumpro as a replacement. 11417 * The -funsafe-math-optimizations option now automatically turns on 11418 -fno-trapping-math in addition to -fno-signed-zeros, as it enables 11419 reassociation and thus may introduce or remove traps. 11420 * The -ftree-vectorize option is now on by default under -O3. In 11421 order to generate code for a SIMD extension, it has to be enabled 11422 as well: use -maltivec for PowerPC platforms and -msse/-msse2 for 11423 i?86 and x86_64. 11424 * More information on porting to GCC 4.3 from previous versions of 11425 GCC can be found in the [7]porting guide for this release. 11426 11427 General Optimizer Improvements 11428 11429 * The GCC middle-end has been integrated with the MPFR library. This 11430 allows GCC to evaluate and replace at compile-time calls to 11431 built-in math functions having constant arguments with their 11432 mathematically equivalent results. In making use of MPFR, GCC can 11433 generate correct results regardless of the math library 11434 implementation or floating point precision of the host platform. 11435 This also allows GCC to generate identical results regardless of 11436 whether one compiles in native or cross-compile configurations to a 11437 particular target. The following built-in functions take advantage 11438 of this new capability: acos, acosh, asin, asinh, atan2, atan, 11439 atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1, 11440 fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10, 11441 log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh, 11442 tan, tanh, tgamma, y0, y1 and yn. The float and long double 11443 variants of these functions (e.g. sinf and sinl) are also handled. 11444 The sqrt and cabs functions with constant arguments were already 11445 optimized in prior GCC releases. Now they also use MPFR. 11446 * A new forward propagation pass on RTL was added. The new pass 11447 replaces several slower transformations, resulting in compile-time 11448 improvements as well as better code generation in some cases. 11449 * A new command-line switch -frecord-gcc-switches has been added to 11450 GCC, although it is only enabled for some targets. The switch 11451 causes the command line that was used to invoke the compiler to be 11452 recorded into the object file that is being created. The exact 11453 format of this recording is target and binary file format 11454 dependent, but it usually takes the form of a note section 11455 containing ASCII text. The switch is related to the -fverbose-asm 11456 switch, but that one only records the information in the assembler 11457 output file as comments, so the information never reaches the 11458 object file. 11459 * The inliner heuristic is now aware of stack frame consumption. New 11460 command-line parameters --param large-stack-frame and --param 11461 large-stack-frame-growth can be used to limit stack frame size 11462 growth caused by inlining. 11463 * During feedback directed optimizations, the expected block size the 11464 memcpy, memset and bzero functions operate on is discovered and for 11465 cases of commonly used small sizes, specialized inline code is 11466 generated. 11467 * __builtin_expect no longer requires its argument to be a compile 11468 time constant. 11469 * Interprocedural optimization was reorganized to work on functions 11470 in SSA form. This enables more precise and cheaper dataflow 11471 analysis and makes writing interprocedural optimizations easier. 11472 The following improvements have been implemented on top of this 11473 framework: 11474 + Pre-inline optimization: Selected local optimization passes 11475 are run before the inliner (and other interprocedural passes) 11476 are executed. This significantly improves the accuracy of code 11477 growth estimates used by the inliner and reduces the overall 11478 memory footprint for large compilation units. 11479 + Early inlining (a simple bottom-up inliner pass inlining only 11480 functions whose body is smaller than the expected call 11481 overhead) is now executed with the early optimization passes, 11482 thus inlining already optimized function bodies into an 11483 unoptimized function that is subsequently optimized by early 11484 optimizers. This enables the compiler to quickly eliminate 11485 abstraction penalty in C++ programs. 11486 + Interprocedural constant propagation now operate on SSA form 11487 increasing accuracy of the analysis. 11488 * A new internal representation for GIMPLE statements has been 11489 contributed, resulting in compile-time memory savings. 11490 * The vectorizer was enhanced to support vectorization of outer 11491 loops, intra-iteration parallelism (loop-aware SLP), vectorization 11492 of strided accesses and loops with multiple data-types. Run-time 11493 dependency testing using loop versioning was added. The cost model, 11494 turned on by -fvect-cost-model, was developed. 11495 11496 New Languages and Language specific improvements 11497 11498 * We have added new command-line options 11499 -finstrument-functions-exclude-function-list and 11500 -finstrument-functions-exclude-file-list. They provide more control 11501 over which functions are annotated by the -finstrument-functions 11502 option. 11503 11504 C family 11505 11506 * Implicit conversions between generic vector types are now only 11507 permitted when the two vectors in question have the same number of 11508 elements and compatible element types. (Note that the restriction 11509 involves compatible element types, not implicitly-convertible 11510 element types: thus, a vector type with element type int may not be 11511 implicitly converted to a vector type with element type unsigned 11512 int.) This restriction, which is in line with specifications for 11513 SIMD architectures such as AltiVec, may be relaxed using the flag 11514 -flax-vector-conversions. This flag is intended only as a 11515 compatibility measure and should not be used for new code. 11516 * -Warray-bounds has been added and is now enabled by default for 11517 -Wall . It produces warnings for array subscripts that can be 11518 determined at compile time to be always out of bounds. 11519 -Wno-array-bounds will disable the warning. 11520 * The constructor and destructor function attributes now accept 11521 optional priority arguments which control the order in which the 11522 constructor and destructor functions are run. 11523 * New [8]command-line options -Wtype-limits, -Wold-style-declaration, 11524 -Wmissing-parameter-type, -Wempty-body, -Wclobbered and 11525 -Wignored-qualifiers have been added for finer control of the 11526 diverse warnings enabled by -Wextra. 11527 * A new function attribute alloc_size has been added to mark up 11528 malloc style functions. For constant sized allocations this can be 11529 used to find out the size of the returned pointer using the 11530 __builtin_object_size() function for buffer overflow checking and 11531 similar. This supplements the already built-in malloc and calloc 11532 constant size handling. 11533 * Integer constants written in binary are now supported as a GCC 11534 extension. They consist of a prefix 0b or 0B, followed by a 11535 sequence of 0 and 1 digits. 11536 * A new predefined macro __COUNTER__ has been added. It expands to 11537 sequential integral values starting from 0. In conjunction with the 11538 ## operator, this provides a convenient means to generate unique 11539 identifiers. 11540 * A new command-line option -fdirectives-only has been added. It 11541 enables a special preprocessing mode which improves the performance 11542 of applications like distcc and ccache. 11543 * Fixed-point data types and operators have been added. They are 11544 based on Chapter 4 of the Embedded-C specification (n1169.pdf). 11545 Currently, only MIPS targets are supported. 11546 * Decimal floating-point arithmetic based on draft ISO/IEC TR 24732, 11547 N1241, is now supported as a GCC extension to C for targets 11548 i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu, 11549 and x86_64-*-linux-gnu. The feature introduces new data types 11550 _Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF, 11551 DD, and DL. 11552 11553 C++ 11554 11555 * [9]Experimental support for the upcoming ISO C++ standard, C++0x. 11556 * -Wc++0x-compat has been added and is now enabled by default for 11557 -Wall. It produces warnings for constructs whose meaning differs 11558 between ISO C++ 1998 and C++0x. 11559 * The -Wparentheses option now works for C++ as it does for C. It 11560 warns if parentheses are omitted when operators with confusing 11561 precedence are nested. It also warns about ambiguous else 11562 statements. Since -Wparentheses is enabled by -Wall, this may cause 11563 additional warnings with existing C++ code which uses -Wall. These 11564 new warnings may be disabled by using -Wall -Wno-parentheses. 11565 * The -Wmissing-declarations now works for C++ as it does for C. 11566 * The -fvisibility-ms-compat flag was added, to make it easier to 11567 port larger projects using shared libraries from Microsoft's Visual 11568 Studio to ELF and Mach-O systems. 11569 * C++ attribute handling has been overhauled for template arguments 11570 (ie dependent types). In particular, __attribute__((aligned(T))); 11571 works for C++ types. 11572 11573 Runtime Library (libstdc++) 11574 11575 * [10]Experimental support for the upcoming ISO C++ standard, C++0x. 11576 * Support for TR1 mathematical special functions and regular 11577 expressions. 11578 * Default what implementations give more elaborate exception strings 11579 for bad_cast, bad_typeid, bad_exception, and bad_alloc. 11580 * Header dependencies have been streamlined, reducing unnecessary 11581 includes and pre-processed bloat. 11582 * Variadic template implementations of items in <tuple> and 11583 <functional>. 11584 * An experimental [11]parallel mode has been added. This is a 11585 parallel implementation of many C++ Standard library algorithms, 11586 like std::accumulate, std::for_each, std::transform, or std::sort, 11587 to give but four examples. These algorithms can be substituted for 11588 the normal (sequential) libstdc++ algorithms on a piecemeal basis, 11589 or all existing algorithms can be transformed via the 11590 -D_GLIBCXX_PARALLEL macro. 11591 * Debug mode versions of classes in <unordered_set> and 11592 <unordered_map>. 11593 * Formal deprecation of <ext/hash_set> and <ext/hash_map>, which are 11594 now <backward/hash_set> and <backward/hash_map>. This code: 11595 #include <ext/hash_set> 11596 __gnu_cxx::hash_set<int> s; 11597 11598 Can be transformed (in order of preference) to: 11599 #include <tr1/unordered_set> 11600 std::tr1::unordered_set<int> s; 11601 11602 or 11603 #include <backward/hash_set> 11604 __gnu_cxx::hash_set<int> s; 11605 11606 Similar transformations apply to __gnu_cxx::hash_map, 11607 __gnu_cxx::hash_multimap, __gnu_cxx::hash_set, 11608 __gnu_cxx::hash_multiset. 11609 11610 Fortran 11611 11612 * Due to the fact that the GMP and MPFR libraries are required for 11613 all languages, Fortran is no longer special in this regard and is 11614 available by default. 11615 * The [12]-fexternal-blas option has been added, which generates 11616 calls to BLAS routines for intrinsic matrix operations such as 11617 matmul rather than using the built-in algorithms. 11618 * Support to give a backtrace (compiler flag -fbacktrace or 11619 environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems 11620 only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a 11621 run-time error occured. 11622 * GNU Fortran now defines __GFORTRAN__ when it runs the C 11623 preprocessor (CPP). 11624 * The [13]-finit-local-zero, -finit-real, -finit-integer, 11625 -finit-character, and -finit-logical options have been added, which 11626 can be used to initialize local variables. 11627 * The intrinsic procedures [14]GAMMA and [15]LGAMMA have been added, 11628 which calculate the Gamma function and its logarithm. Use EXTERNAL 11629 gamma if you want to use your own gamma function. 11630 * GNU Fortran now regards the backslash character as literal (as 11631 required by the Fortran 2003 standard); using [16]-fbackslash GNU 11632 Fortran interprets backslashes as C-style escape characters. 11633 * The [17]interpretation of binary, octal and hexadecimal (BOZ) 11634 literal constants has been changed. Before they were always 11635 interpreted as integer; now they are bit-wise transferred as 11636 argument of INT, REAL, DBLE and CMPLX as required by the Fortran 11637 2003 standard, and for real and complex variables in DATA 11638 statements or when directly assigned to real and complex variables. 11639 Everywhere else and especially in expressions they are still 11640 regarded as integer constants. 11641 * Fortran 2003 support has been extended: 11642 + Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE 11643 + Pointer intent 11644 + Intrinsic module ISO_ENV_FORTRAN 11645 + Interoperability with C (ISO C Bindings) 11646 + ABSTRACT INTERFACES and PROCEDURE statements (without POINTER 11647 attribute) 11648 + Fortran 2003 BOZ 11649 11650 Java (GCJ) 11651 11652 * GCJ now uses the Eclipse Java compiler for its Java parsing needs. 11653 This enables the use of all 1.5 language features, and fixes most 11654 existing front end bugs. 11655 * libgcj now supports all 1.5 language features which require runtime 11656 support: foreach, enum, annotations, generics, and auto-boxing. 11657 * We've made many changes to the tools shipped with gcj. 11658 + The old jv-scan tool has been removed. This tool never really 11659 worked properly. There is no replacement. 11660 + gcjh has been rewritten. Some of its more obscure options no 11661 longer work, but are still recognized in an attempt at 11662 compatibility. gjavah is a new program with similar 11663 functionality but different command-line options. 11664 + grmic and grmiregistry have been rewritten. grmid has been 11665 added. 11666 + gjar replaces the old fastjar. 11667 + gjarsigner (used for signing jars), gkeytool (used for key 11668 management), gorbd (for CORBA), gserialver (computes 11669 serialization UIDs), and gtnameserv (also for CORBA) are now 11670 installed. 11671 * The ability to dump the contents of the java run time heap to a 11672 file for off-line analysis has been added. The heap dumps may be 11673 analyzed with the new gc-analyze tool. They may be generated on 11674 out-of-memory conditions or on demand and are controlled by the new 11675 run time class gnu.gcj.util.GCInfo. 11676 * java.util.TimeZone can now read files from /usr/share/zoneinfo to 11677 provide correct, updated, timezone information. This means that 11678 packagers no longer have to update libgcj when a time zone change 11679 is published. 11680 11681 New Targets and Target Specific Improvements 11682 11683 IA-32/x86-64 11684 11685 * Tuning for Intel Core 2 processors is available via -mtune=core2 11686 and -march=core2. 11687 * Tuning for AMD Geode processors is available via -mtune=geode and 11688 -march=geode. 11689 * Code generation of block move (memcpy) and block set (memset) was 11690 rewritten. GCC can now pick the best algorithm (loop, unrolled 11691 loop, instruction with rep prefix or a library call) based on the 11692 size of the block being copied and the CPU being optimized for. A 11693 new option -minline-stringops-dynamically has been added. With this 11694 option string operations of unknown size are expanded such that 11695 small blocks are copied by in-line code, while for large blocks a 11696 library call is used. This results in faster code than 11697 -minline-all-stringops when the library implementation is capable 11698 of using cache hierarchy hints. The heuristic choosing the 11699 particular algorithm can be overwritten via -mstringop-strategy. 11700 Newly also memset of values different from 0 is inlined. 11701 * GCC no longer places the cld instruction before string operations. 11702 Both i386 and x86-64 ABI documents mandate the direction flag to be 11703 clear at the entry of a function. It is now invalid to set the flag 11704 in asm statement without reseting it afterward. 11705 * Support for SSSE3 built-in functions and code generation are 11706 available via -mssse3. 11707 * Support for SSE4.1 built-in functions and code generation are 11708 available via -msse4.1. 11709 * Support for SSE4.2 built-in functions and code generation are 11710 available via -msse4.2. 11711 * Both SSE4.1 and SSE4.2 support can be enabled via -msse4. 11712 * A new set of options -mpc32, -mpc64 and -mpc80 have been added to 11713 allow explicit control of x87 floating point precision. 11714 * Support for __float128 (TFmode) IEEE quad type and corresponding 11715 TCmode IEEE complex quad type is available via the soft-fp library 11716 on x86_64 targets. This includes basic arithmetic operations 11717 (addition, subtraction, negation, multiplication and division) on 11718 __float128 real and TCmode complex values, the full set of IEEE 11719 comparisons between __float128 values, conversions to and from 11720 float, double and long double floating point types, as well as 11721 conversions to and from signed or unsigned integer, signed or 11722 unsigned long integer and signed or unsigned quad (TImode) integer 11723 types. Additionally, all operations generate the full set of IEEE 11724 exceptions and support the full set of IEEE rounding modes. 11725 * GCC can now utilize the ACML library for vectorizing calls to a set 11726 of C99 functions on x86_64 if -mveclibabi=acml is specified and you 11727 link to an ACML ABI compatible library. 11728 11729 ARM 11730 11731 * Compiler and Library support for Thumb-2 and the ARMv7 architecture 11732 has been added. 11733 11734 CRIS 11735 11736 New features 11737 11738 * Compiler and Library support for the CRIS v32 architecture, as 11739 found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been 11740 added. 11741 11742 Configuration changes 11743 11744 * The cris-*-elf target now includes support for CRIS v32, including 11745 libraries, through the -march=v32 option. 11746 * A new crisv32-*-elf target defaults to generate code for CRIS v32. 11747 * A new crisv32-*-linux* target defaults to generate code for CRIS 11748 v32. 11749 * The cris-*-aout target has been obsoleted. 11750 11751 Improved support for built-in functions 11752 11753 * GCC can now use the lz and swapwbr instructions to implement the 11754 __builtin_clz, __builtin_ctz and __builtin_ffs family of functions. 11755 * __builtin_bswap32 is now implemented using the swapwb instruction, 11756 when available. 11757 11758 m68k and ColdFire 11759 11760 New features 11761 11762 * Support for several new ColdFire processors has been added. You can 11763 generate code for them using the new -mcpu option. 11764 * All targets now support ColdFire processors. 11765 * m68k-uclinux targets have improved support for C++ constructors and 11766 destructors, and for shared libraries. 11767 * It is now possible to set breakpoints on the first or last line of 11768 a function, even if there are no statements on that line. 11769 11770 Optimizations 11771 11772 * Support for sibling calls has been added. 11773 * More use is now made of the ColdFire mov3q instruction. 11774 * __builtin_clz is now implemented using the ff1 ColdFire 11775 instruction, when available. 11776 * GCC now honors the -m68010 option. 68010 code now uses clr rather 11777 than move to zero volatile memory. 11778 * 68020 targets and above can now use symbol(index.size*scale) 11779 addresses for indexed array accesses. Earlier compilers would 11780 always load the symbol into a base register first. 11781 11782 Configuration changes 11783 11784 * All m68k and ColdFire targets now allow the default processor to be 11785 set at configure time using --with-cpu. 11786 * A --with-arch configuration option has been added. This option 11787 allows you to restrict a target to ColdFire or non-ColdFire 11788 processors. 11789 11790 Preprocessor macros 11791 11792 * An __mcfv*__ macro is now defined for all ColdFire targets. 11793 (Earlier versions of GCC only defined __mcfv4e__.) 11794 * __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added. 11795 * All targets now define __mc68010 and __mc68010__ when generating 11796 68010 code. 11797 11798 Command-line changes 11799 11800 * New command-line options -march, -mcpu, -mtune and -mhard-float 11801 have been added. These options apply to both m68k and ColdFire 11802 targets. 11803 * -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative 11804 versions of -mshort, etc. 11805 * -fforce-addr has been removed. It is now ignored by the compiler. 11806 11807 Other improvements 11808 11809 * ColdFire targets now try to maintain a 4-byte-aligned stack where 11810 possible. 11811 * m68k-uclinux targets now try to avoid situations that lead to the 11812 load-time error: BINFMT_FLAT: reloc outside program. 11813 11814 MIPS 11815 11816 Changes to existing configurations 11817 11818 * libffi and libjava now support all three GNU/Linux ABIs: o32, n32 11819 and n64. Every GNU/Linux configuration now builds these libraries 11820 by default. 11821 * GNU/Linux configurations now generate -mno-shared code unless 11822 overridden by -fpic, -fPIC, -fpie or -fPIE. 11823 * mipsisa32*-linux-gnu configurations now generate hard-float code by 11824 default, just like other mipsisa32* and mips*-linux-gnu 11825 configurations. You can build a soft-float version of any 11826 mips*-linux-gnu configuration by passing --with-float=soft to 11827 configure. 11828 * mips-wrs-vxworks now supports run-time processes (RTPs). 11829 11830 Changes to existing command-line options 11831 11832 * The -march and -mtune options no longer accept 24k as a processor 11833 name. Please use 24kc, 24kf2_1 or 24kf1_1 instead. 11834 * The -march and -mtune options now accept 24kf2_1, 24kef2_1 and 11835 34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The 11836 options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for 11837 24kx, 24kex and 34kx. 11838 11839 New configurations 11840 11841 GCC now supports the following configurations: 11842 * mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by 11843 default. Earlier releases also recognized this configuration, but 11844 they treated it in the same way as mipsisa32*-linux-gnu*. Note that 11845 you can customize any mips*-linux-gnu* configuration to a 11846 particular ISA or processor by passing an appropriate --with-arch 11847 option to configure. 11848 * mipsisa*-sde-elf*, which provides compatibility with MIPS 11849 Technologies' SDE toolchains. The configuration uses the SDE 11850 libraries by default, but you can use it like other newlib-based 11851 ELF configurations by passing --with-newlib to configure. It is the 11852 only configuration besides mips64vr*-elf* to build MIPS16 as well 11853 as non-MIPS16 libraries. 11854 * mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf* 11855 configuration, but uses the o32 and o64 ABIs instead of the 32-bit 11856 and 64-bit forms of the EABI. 11857 11858 New processors and application-specific extensions 11859 11860 * Support for the SmartMIPS ASE is available through the new 11861 -msmartmips option. 11862 * Support for revision 2 of the DSP ASE is available through the new 11863 -mdspr2 option. A new preprocessor macro called __mips_dsp_rev 11864 indicates the revision of the ASE in use. 11865 * Support for the 4KS and 74K families of processors is available 11866 through the -march and -mtune options. 11867 11868 Improved support for built-in functions 11869 11870 * GCC can now use load-linked, store-conditional and sync 11871 instructions to implement atomic built-in functions such as 11872 __sync_fetch_and_add. The memory reference must be 4 bytes wide for 11873 32-bit targets and either 4 or 8 bytes wide for 64-bit targets. 11874 * GCC can now use the clz and dclz instructions to implement the 11875 __builtin_ctz and __builtin_ffs families of functions. 11876 * There is a new __builtin___clear_cache function for flushing the 11877 instruction cache. GCC expands this function inline on MIPS32 11878 revision 2 targets, otherwise it calls the function specified by 11879 -mcache-flush-func. 11880 11881 MIPS16 improvements 11882 11883 * GCC can now compile objects that contain a mixture of MIPS16 and 11884 non-MIPS16 code. There are two new attributes, mips16 and nomips16, 11885 for specifying which mode a function should use. 11886 * A new option called -minterlink-mips16 makes non-MIPS16 code 11887 link-compatible with MIPS16 code. 11888 * After many bug fixes, the long-standing MIPS16 -mhard-float support 11889 should now work fairly reliably. 11890 * GCC can now use the MIPS16e save and restore instructions. 11891 * -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled 11892 with -G0 -fsection-anchors is often smaller than code compiled with 11893 -G8. However, please note that you must usually compile all objects 11894 in your application with the same -G option; see the documentation 11895 of -G for details. 11896 * A new option called-mcode-readable specifies which instructions are 11897 allowed to load from the code segment. -mcode-readable=yes is the 11898 default and says that any instruction may load from the code 11899 segment. The other alternatives are -mcode-readable=pcrel, which 11900 says that only PC-relative MIPS16 instructions may load from the 11901 code segment, and -mcode-readable=no, which says that no 11902 instruction may do so. Please see the documentation for more 11903 details, including example uses. 11904 11905 Small-data improvements 11906 11907 There are three new options for controlling small data: 11908 * -mno-extern-sdata, which disables small-data accesses for 11909 externally-defined variables. Code compiled with -Gn 11910 -mno-extern-sdata will be link-compatible with any -G setting 11911 between -G0 and -Gn inclusive. 11912 * -mno-local-sdata, which disables the use of small-data sections for 11913 data that is not externally visible. This option can be a useful 11914 way of reducing small-data usage in less performance-critical parts 11915 of an application. 11916 * -mno-gpopt, which disables the use of the $gp register while still 11917 honoring the -G limit when placing externally-visible data. This 11918 option implies -mno-extern-sdata and -mno-local-sdata and it can be 11919 useful in situations where $gp does not necessarily hold the 11920 expected value. 11921 11922 Miscellaneous improvements 11923 11924 * There is a new option called -mbranch-cost for tweaking the 11925 perceived cost of branches. 11926 * If GCC is configured to use a version of GAS that supports the 11927 .gnu_attribute directive, it will use that directive to record 11928 certain properties of the output code. .gnu_attribute is new to GAS 11929 2.18. 11930 * There are two new function attributes, near and far, for overriding 11931 the command-line setting of -mlong-calls on a function-by-function 11932 basis. 11933 * -mfp64, which previously required a 64-bit target, now works with 11934 MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and 11935 mipsisa*-sde-elf* configurations provide suitable library support. 11936 * GCC now recognizes the -mdmx and -mmt options and passes them down 11937 to the assembler. It does nothing else with the options at present. 11938 11939 SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture 11940 (BEA) 11941 11942 * Support has been added for this new architecture. 11943 11944 RS6000 (POWER/PowerPC) 11945 11946 * Support for the PowerPC 750CL paired-single instructions has been 11947 added with a new powerpc-*-linux*paired* target configuration. It 11948 is enabled by an associated -mpaired option and can be accessed 11949 using new built-in functions. 11950 * Support for auto-detecting architecture and system configuration to 11951 auto-select processor optimization tuning. 11952 * Support for VMX on AIX 5.3 has been added. 11953 * Support for AIX Version 6.1 has been added. 11954 11955 S/390, zSeries and System z9 11956 11957 * Support for the IBM System z9 EC/BC processor (z9 GA3) has been 11958 added. When using the -march=z9-ec option, the compiler will 11959 generate code making use of instructions provided by the decimal 11960 floating point facility and the floating point conversion facility 11961 (pfpo). Besides the instructions used to implement decimal floating 11962 point operations these facilities also contain instructions to move 11963 between general purpose and floating point registers and to modify 11964 and copy the sign-bit of floating point values. 11965 * When the -march=z9-ec option is used the new 11966 -mhard-dfp/-mno-hard-dfp options can be used to specify whether the 11967 decimal floating point hardware instructions will be used or not. 11968 If none of them is given the hardware support is enabled by 11969 default. 11970 * The -mstack-guard option can now be omitted when using stack 11971 checking via -mstack-size in order to let GCC choose a sensible 11972 stack guard value according to the frame size of each function. 11973 * Various changes to improve performance of generated code have been 11974 implemented, including: 11975 + The condition code set by an add logical with carry 11976 instruction is now available for overflow checks like: a + b + 11977 carry < b. 11978 + The test data class instruction is now used to implement 11979 sign-bit and infinity checks of binary and decimal floating 11980 point numbers. 11981 11982 SPARC 11983 11984 * Support for the Sun UltraSPARC T2 (Niagara 2) processor has been 11985 added. 11986 11987 Xtensa 11988 11989 * Stack unwinding for exception handling now uses by default a 11990 specialized version of DWARF unwinding. This is not 11991 binary-compatible with the setjmp/longjmp (sjlj) unwinding used for 11992 Xtensa with previous versions of GCC. 11993 * For Xtensa processors that include the Conditional Store option, 11994 the built-in functions for atomic memory access are now implemented 11995 using S32C1I instructions. 11996 * If the Xtensa NSA option is available, GCC will use it to implement 11997 the __builtin_ctz and __builtin_clz functions. 11998 11999 Documentation improvements 12000 12001 * Existing libstdc++ documentation has been edited and restructured 12002 into a single DocBook XML manual. The results can be viewed online 12003 [18]here. 12004 12005 Other significant improvements 12006 12007 * The compiler's --help command-line option has been extended so that 12008 it now takes an optional set of arguments. These arguments restrict 12009 the information displayed to specific classes of command-line 12010 options, and possibly only a subset of those options. It is also 12011 now possible to replace the descriptive text associated with each 12012 displayed option with an indication of its current value, or for 12013 binary options, whether it has been enabled or disabled. 12014 Here are some examples. The following will display all the options 12015 controlling warning messages: 12016 --help=warnings 12017 12018 Whereas this will display all the undocumented, target specific 12019 options: 12020 --help=target,undocumented 12021 12022 This sequence of commands will display the binary optimizations 12023 that are enabled by -O3: 12024 gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts 12025 gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts 12026 diff /tmp/O2-opts /tmp/O3-opts | grep enabled 12027 12028 * The configure options --with-pkgversion and --with-bugurl have been 12029 added. These allow distributors of GCC to include a 12030 distributor-specific string in manuals and --version output and to 12031 specify the URL for reporting bugs in their versions of GCC. 12032 12033 GCC 4.3.1 12034 12035 This is the [19]list of problem reports (PRs) from GCC's bug tracking 12036 system that are known to be fixed in the 4.3.1 release. This list might 12037 not be complete (that is, it is possible that some PRs that have been 12038 fixed are not listed here). 12039 12040 Target Specific Changes 12041 12042 IA-32/x86-64 12043 12044 ABI changes 12045 12046 * Starting with GCC 4.3.1, decimal floating point variables are 12047 aligned to their natural boundaries when they are passed on the 12048 stack for i386. 12049 12050 Command-line changes 12051 12052 * Starting with GCC 4.3.1, the -mcld option has been added to 12053 automatically generate a cld instruction in the prologue of 12054 functions that use string instructions. This option is used for 12055 backward compatibility on some operating systems and can be enabled 12056 by default for 32-bit x86 targets by configuring GCC with the 12057 --enable-cld configure option. 12058 12059 GCC 4.3.2 12060 12061 This is the [20]list of problem reports (PRs) from GCC's bug tracking 12062 system that are known to be fixed in the 4.3.2 release. This list might 12063 not be complete (that is, it is possible that some PRs that have been 12064 fixed are not listed here). 12065 12066 GCC 4.3.3 12067 12068 This is the [21]list of problem reports (PRs) from GCC's bug tracking 12069 system that are known to be fixed in the 4.3.3 release. This list might 12070 not be complete (that is, it is possible that some PRs that have been 12071 fixed are not listed here). 12072 12073 GCC 4.3.4 12074 12075 This is the [22]list of problem reports (PRs) from GCC's bug tracking 12076 system that are known to be fixed in the 4.3.4 release. This list might 12077 not be complete (that is, it is possible that some PRs that have been 12078 fixed are not listed here). 12079 12080 GCC 4.3.5 12081 12082 This is the [23]list of problem reports (PRs) from GCC's bug tracking 12083 system that are known to be fixed in the 4.3.5 release. This list might 12084 not be complete (that is, it is possible that some PRs that have been 12085 fixed are not listed here). 12086 12087 GCC 4.3.6 12088 12089 This is the [24]list of problem reports (PRs) from GCC's bug tracking 12090 system that are known to be fixed in the 4.3.6 release. This list might 12091 not be complete (that is, it is possible that some PRs that have been 12092 fixed are not listed here). 12093 12094 12095 For questions related to the use of GCC, please consult these web 12096 pages and the [25]GCC manuals. If that fails, the 12097 [26]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12098 web pages and the development of GCC are welcome on our developer 12099 list at [27]gcc (a] gcc.gnu.org. All of [28]our lists have public 12100 archives. 12101 12102 Copyright (C) [29]Free Software Foundation, Inc. Verbatim copying and 12103 distribution of this entire article is permitted in any medium, 12104 provided this notice is preserved. 12105 12106 These pages are [30]maintained by the GCC team. Last modified 12107 2021-07-28[31]. 12108 12109 References 12110 12111 1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.5 12112 2. https://gmplib.org/ 12113 3. https://www.mpfr.org/ 12114 4. https://gcc.gnu.org/install/prerequisites.html 12115 5. https://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html 12116 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 12117 7. http://gcc.gnu.org/gcc-4.3/porting_to.html 12118 8. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 12119 9. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 12120 10. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 12121 11. https://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html 12122 12. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options 12123 13. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167 12124 14. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html 12125 15. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html 12126 16. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html 12127 17. https://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html 12128 18. https://gcc.gnu.org/onlinedocs/libstdc++/ 12129 19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1 12130 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2 12131 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3 12132 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4 12133 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.5 12134 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.6 12135 25. https://gcc.gnu.org/onlinedocs/ 12136 26. mailto:gcc-help (a] gcc.gnu.org 12137 27. mailto:gcc (a] gcc.gnu.org 12138 28. https://gcc.gnu.org/lists.html 12139 29. https://www.fsf.org/ 12140 30. https://gcc.gnu.org/about.html 12141 31. http://validator.w3.org/check/referer 12142 ====================================================================== 12143 http://gcc.gnu.org/gcc-4.2/index.html 12144 GCC 4.2 Release Series 12145 12146 (This release series is no longer supported.) 12147 12148 May 19, 2008 12149 12150 The [1]GNU project and the GCC developers are pleased to announce the 12151 release of GCC 4.2.4. 12152 12153 This release is a bug-fix release, containing fixes for regressions in 12154 GCC 4.2.3 relative to previous releases of GCC. 12155 12156 Release History 12157 12158 GCC 4.2.4 12159 May 19, 2008 ([2]changes) 12160 12161 GCC 4.2.3 12162 February 1, 2008 ([3]changes) 12163 12164 GCC 4.2.2 12165 October 7, 2007 ([4]changes) 12166 12167 GCC 4.2.1 12168 July 18, 2007 ([5]changes) 12169 12170 GCC 4.2.0 12171 May 13, 2007 ([6]changes) 12172 12173 References and Acknowledgements 12174 12175 GCC used to stand for the GNU C Compiler, but since the compiler 12176 supports several other languages aside from C, it now stands for the 12177 GNU Compiler Collection. 12178 12179 A list of [7]successful builds is updated as new information becomes 12180 available. 12181 12182 The GCC developers would like to thank the numerous people that have 12183 contributed new features, improvements, bug fixes, and other changes as 12184 well as test results to GCC. This [8]amazing group of volunteers is 12185 what makes GCC successful. 12186 12187 For additional information about GCC please refer to the [9]GCC project 12188 web site or contact the [10]GCC development mailing list. 12189 12190 To obtain GCC please use [11]our mirror sites or [12]our version 12191 control system. 12192 12193 12194 For questions related to the use of GCC, please consult these web 12195 pages and the [13]GCC manuals. If that fails, the 12196 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12197 web pages and the development of GCC are welcome on our developer 12198 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 12199 archives. 12200 12201 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 12202 distribution of this entire article is permitted in any medium, 12203 provided this notice is preserved. 12204 12205 These pages are [18]maintained by the GCC team. Last modified 12206 2021-07-28[19]. 12207 12208 References 12209 12210 1. http://www.gnu.org/ 12211 2. http://gcc.gnu.org/gcc-4.2/changes.html 12212 3. http://gcc.gnu.org/gcc-4.2/changes.html 12213 4. http://gcc.gnu.org/gcc-4.2/changes.html 12214 5. http://gcc.gnu.org/gcc-4.2/changes.html 12215 6. http://gcc.gnu.org/gcc-4.2/changes.html 12216 7. http://gcc.gnu.org/gcc-4.2/buildstat.html 12217 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 12218 9. http://gcc.gnu.org/index.html 12219 10. mailto:gcc (a] gcc.gnu.org 12220 11. http://gcc.gnu.org/mirrors.html 12221 12. http://gcc.gnu.org/git.html 12222 13. https://gcc.gnu.org/onlinedocs/ 12223 14. mailto:gcc-help (a] gcc.gnu.org 12224 15. mailto:gcc (a] gcc.gnu.org 12225 16. https://gcc.gnu.org/lists.html 12226 17. https://www.fsf.org/ 12227 18. https://gcc.gnu.org/about.html 12228 19. http://validator.w3.org/check/referer 12229 ====================================================================== 12230 http://gcc.gnu.org/gcc-4.2/changes.html 12231 GCC 4.2 Release Series 12232 Changes, New Features, and Fixes 12233 12234 Caveats 12235 12236 * GCC no longer accepts the -fshared-data option. This option has had 12237 no effect in any GCC 4 release; the targets to which the option 12238 used to apply had been removed before GCC 4.0. 12239 12240 General Optimizer Improvements 12241 12242 * New command-line options specify the possible relationships among 12243 parameters and between parameters and global data. For example, 12244 -fargument-noalias-anything specifies that arguments do not alias 12245 any other storage. 12246 Each language will automatically use whatever option is required by 12247 the language standard. You should not need to use these options 12248 yourself. 12249 12250 New Languages and Language specific improvements 12251 12252 * [1]OpenMP is now supported for the C, C++ and Fortran compilers. 12253 * New command-line options -fstrict-overflow and -Wstrict-overflow 12254 have been added. -fstrict-overflow tells the compiler that it may 12255 assume that the program follows the strict signed overflow 12256 semantics permitted for the language: for C and C++ this means that 12257 the compiler may assume that signed overflow does not occur. For 12258 example, a loop like 12259 for (i = 1; i > 0; i *= 2) 12260 12261 is presumably intended to continue looping until i overflows. With 12262 -fstrict-overflow, the compiler may assume that signed overflow 12263 will not occur, and transform this into an infinite loop. 12264 -fstrict-overflow is turned on by default at -O2, and may be 12265 disabled via -fno-strict-overflow. The -Wstrict-overflow option may 12266 be used to warn about cases where the compiler assumes that signed 12267 overflow will not occur. It takes five different levels: 12268 -Wstrict-overflow=1 to 5. See the [2]documentation for details. 12269 -Wstrict-overflow=1 is enabled by -Wall. 12270 * The new command-line option -fno-toplevel-reorder directs GCC to 12271 emit top-level functions, variables, and asm statements in the same 12272 order that they appear in the input file. This is intended to 12273 support existing code which relies on a particular ordering (for 12274 example, code which uses top-level asm statements to switch 12275 sections). For new code, it is generally better to use function and 12276 variable attributes. The -fno-toplevel-reorder option may be used 12277 for most cases which currently use -fno-unit-at-a-time. The 12278 -fno-unit-at-a-time option will be removed in some future version 12279 of GCC. If you know of a case which requires -fno-unit-at-a-time 12280 which is not fixed by -fno-toplevel-reorder, please open a bug 12281 report. 12282 12283 C family 12284 12285 * The pragma redefine_extname will now macro expand its tokens for 12286 compatibility with SunPRO. 12287 * In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct 12288 GCC to handle inline functions as specified in the C99 standard. In 12289 preparation for this, GCC 4.2 will warn about any use of non-static 12290 inline functions in gnu99 or c99 mode. This new warning may be 12291 disabled with the new gnu_inline function attribute or the new 12292 -fgnu89-inline command-line option. Also, GCC 4.2 and later will 12293 define one of the preprocessor macros __GNUC_GNU_INLINE__ or 12294 __GNUC_STDC_INLINE__ to indicate the semantics of inline functions 12295 in the current compilation. 12296 * A new command-line option -Waddress has been added to warn about 12297 suspicious uses of memory addresses as, for example, using the 12298 address of a function in a conditional expression, and comparisons 12299 against the memory address of a string literal. This warning is 12300 enabled by -Wall. 12301 12302 C++ 12303 12304 * C++ visibility handling has been overhauled. 12305 Restricted visiblity is propagated from classes to members, from 12306 functions to local statics, and from templates and template 12307 arguments to instantiations, unless the latter has explicitly 12308 declared visibility. 12309 The visibility attribute for a class must come between the 12310 class-key and the name, not after the closing brace. 12311 Attributes are now allowed for enums and elaborated-type-specifiers 12312 that only declare a type. 12313 Members of the anonymous namespace are now local to a particular 12314 translation unit, along with any other declarations which use them, 12315 though they are still treated as having external linkage for 12316 language semantics. 12317 * The (undocumented) extension which permitted templates with default 12318 arguments to be bound to template template parameters with fewer 12319 parameters has been removed. For example: 12320 template <template <typename> class C> 12321 void f(C<double>) {} 12322 12323 template <typename T, typename U = int> 12324 struct S {}; 12325 12326 template void f(S<double>); 12327 12328 is no longer accepted by G++. The reason this code is not accepted 12329 is that S is a template with two parameters; therefore, it cannot 12330 be bound to C which has only one parameter. 12331 * The <?, >?, <?=, and >?= operators, deprecated in previous GCC 12332 releases, have been removed. 12333 * The command-line option -fconst-strings, deprecated in previous GCC 12334 releases, has been removed. 12335 * The configure variable enable-__cxa_atexit is now enabled by 12336 default for more targets. Enabling this variable is necessary in 12337 order for static destructors to be executed in the correct order, 12338 but it depends upon the presence of a non-standard C library in the 12339 target library in order to work. The variable is now enabled for 12340 more targets which are known to have suitable C libraries. 12341 * -Wextra will produce warnings for if statements with a semicolon as 12342 the only body, to catch code like: 12343 if (a); 12344 return 1; 12345 return 0; 12346 12347 To suppress the warning in valid cases, use { } instead. 12348 * The C++ front end now also produces strict aliasing warnings when 12349 -fstrict-aliasing -Wstrict-aliasing is in effect. 12350 12351 Runtime Library (libstdc++) 12352 12353 * Added support for TR1 <random>, <complex>, and C compatibility 12354 headers. In addition, a lock-free version of shared_ptr was 12355 contributed as part of Phillip Jordan's Google Summer of Code 12356 project on lock-free containers. 12357 * In association with the Summer of Code work on lock-free 12358 containers, the interface for atomic builtins was adjusted, 12359 creating simpler alternatives for non-threaded code paths. Also, 12360 usage was consolidated and all elements were moved from namespace 12361 std to namespace__gnu_cxx. Affected interfaces are the functions 12362 __exchange_and_add, __atomic_add, and the objects __mutex, 12363 __recursive_mutex, and __scoped_lock. 12364 * Support for versioning weak symbol names via namespace association 12365 was added. However, as this changes the names of exported symbols, 12366 this is turned off by default in the current ABI. Intrepid users 12367 can enable this feature by using 12368 --enable-symvers=gnu-versioned-namespace during configuration. 12369 * Revised, simplified, and expanded policy-based associative 12370 containers, including data types for tree and trie forms 12371 (basic_tree, tree, trie), lists (list_update), and both 12372 collision-chaining and probing hash-based containers 12373 (basic_hash_table, cc_hash_table, gp_hash_table). More details per 12374 the [3]documentation. 12375 * The implementation of the debug mode was modified, whereby the 12376 debug namespaces were nested inside of namespace std and namespace 12377 __gnu_cxx in order to resolve some long standing corner cases 12378 involving name lookup. Debug functionality from the policy-based 12379 data structures was consolidated and enabled with the single macro, 12380 _GLIBCXX_DEBUG. See PR 26142 for more information. 12381 * Added extensions for type traits: __conditional_type, 12382 __numeric_traits, __add_unsigned, __removed_unsigned, __enable_if. 12383 * Added a typelist implementation for compile-time meta-programming. 12384 Elements for typelist construction and operation can be found 12385 within namespace __gnu_cxx::typelist. 12386 * Added a new allocator, __gnu_cxx::throw_allocator, for testing 12387 exception-safety. 12388 * Enabled library-wide visibility control, allowing -fvisibility to 12389 be used. 12390 * Consolidated all nested namespaces and the conversion of 12391 __gnu_internal implementation-private details to anonymous 12392 namespaces whenever possible. 12393 * Implemented LWG resolutions DR 431 and DR 538. 12394 12395 Fortran 12396 12397 * Support for allocatable components has been added (TR 15581 and 12398 Fortran 2003). 12399 * Support for the Fortran 2003 streaming IO extension has been added. 12400 * The GNU Fortran compiler now uses 4-byte record markers by default 12401 for unformatted files to be compatible with g77 and most other 12402 compilers. The implementation allows for records greater than 2 GB 12403 and is compatible with several other compilers. Older versions of 12404 gfortran used 8-byte record markers by default (on most systems). 12405 In order to change the length of the record markers, e.g. to read 12406 unformatted files created by older gfortran versions, the 12407 [4]-frecord-marker=8 option can be used. 12408 12409 Java (GCJ) 12410 12411 * A new command-line option -static-libgcj has been added for targets 12412 that use a linker compatible with GNU Binutils. As its name 12413 implies, this causes libgcj to be linked statically. In some cases 12414 this causes the resulting executable to start faster and use less 12415 memory than if the shared version of libgcj were used. However 12416 caution should be used as it can also cause essential parts of the 12417 library to be omitted. Some of these issues are discussed in: 12418 [5]https://gcc.gnu.org/wiki/Statically_linking_libgcj 12419 * fastjar is no longer bundled with GCC. To build libgcj, you will 12420 need either InfoZIP (both zip and unzip) or an external jar 12421 program. In the former case, the GCC build will install a jar shell 12422 script that is based on InfoZIP and provides the same functionality 12423 as fastjar. 12424 12425 New Targets and Target Specific Improvements 12426 12427 IA-32/x86-64 12428 12429 * -mtune=generic can now be used to generate code running well on 12430 common x86 chips. This includes AMD Athlon, AMD Opteron, Intel 12431 Pentium-M, Intel Pentium 4 and Intel Core 2. 12432 * -mtune=native and -march=native will produce code optimized for the 12433 host architecture as detected using the cpuid instruction. 12434 * Added a new command-line option -fstackrealign and and 12435 __attribute__ ((force_align_arg_pointer)) to realign the stack at 12436 runtime. This allows functions compiled with a vector-aligned stack 12437 to be invoked from legacy objects that keep only word-alignment. 12438 12439 SPARC 12440 12441 * The default CPU setting has been changed from V7 to V9 in 32-bit 12442 mode on Solaris 7 and above. This is already the case in 64-bit 12443 mode. It can be overridden by specifying --with-cpu at configure 12444 time. 12445 * Back-end support of built-in functions for atomic memory access has 12446 been implemented. 12447 * Support for the Sun UltraSPARC T1 (Niagara) processor has been 12448 added. 12449 12450 M32C 12451 12452 * Various bug fixes have made some functions (notably, functions 12453 returning structures) incompatible with previous releases. 12454 Recompiling all libraries is recommended. Note that code quality 12455 has considerably improved since 4.1, making a recompile even more 12456 beneficial. 12457 12458 MIPS 12459 12460 * Added support for the Broadcom SB-1A core. 12461 12462 IA-64 12463 12464 * Added support for IA-64 data and control speculation. By default 12465 speculation is enabled only during second scheduler pass. A number 12466 of machine flags was introduced to control the usage of speculation 12467 for both scheduler passes. 12468 12469 HPPA 12470 12471 * Added Java language support (libffi and libjava) for 32-bit HP-UX 12472 11 target. 12473 12474 Obsolete Systems 12475 12476 Documentation improvements 12477 12478 PDF Documentation 12479 12480 * A make pdf target has been added to the top-level makefile, 12481 enabling automated production of PDF documentation files. 12482 (Front-ends external to GCC should modify their Make-lang.in file 12483 to add a lang.pdf: target.) 12484 12485 Other significant improvements 12486 12487 Build system improvements 12488 12489 * All the components of the compiler are now bootstrapped by default. 12490 This improves the resilience to bugs in the system compiler or 12491 binary compatibility problems, as well as providing better testing 12492 of GCC 4.2 itself. In addition, if you build the compiler from a 12493 combined tree, the assembler, linker, etc. will also be 12494 bootstrapped (i.e. built with themselves). 12495 You can disable this behavior, and go back to the pre-GCC 4.2 set 12496 up, by configuring GCC with --disable-bootstrap. 12497 * The rules that configure follows to find target tools resemble more 12498 closely the locations that the built compiler will search. In 12499 addition, you can use the new configure option --with-target-tools 12500 to specify where to find the target tools used during the build, 12501 without affecting what the built compiler will use. 12502 This can be especially useful when building packages of GCC. For 12503 example, you may want to build GCC with GNU as or ld, even if the 12504 resulting compiler to work with the native assembler and linker. To 12505 do so, you can use --with-target-tools to point to the native 12506 tools. 12507 12508 Incompatible changes to the build system 12509 12510 * Front-ends external to GCC should modify their Make-lang.in file to 12511 replace double-colon rules (e.g. dvi::) with normal rules (like 12512 lang.dvi:). Front-end makefile hooks do not use double-colon rules 12513 anymore. 12514 * Up to GCC 4.1, a popular way to specify the target tools used 12515 during the build was to create directories named gas, binutils, 12516 etc. in the build tree, and create links to the tools from there. 12517 This does not work any more when the compiler is bootstrapped. The 12518 new configure option --with-target-tools provides a better way to 12519 achieve the same effect, and works for all native and cross 12520 settings. 12521 12522 12523 For questions related to the use of GCC, please consult these web 12524 pages and the [6]GCC manuals. If that fails, the 12525 [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12526 web pages and the development of GCC are welcome on our developer 12527 list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives. 12528 12529 Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and 12530 distribution of this entire article is permitted in any medium, 12531 provided this notice is preserved. 12532 12533 These pages are [11]maintained by the GCC team. Last modified 12534 2021-07-28[12]. 12535 12536 References 12537 12538 1. http://gcc.gnu.org/projects/gomp/ 12539 2. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 12540 3. https://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html 12541 4. https://gcc.gnu.org/onlinedocs/gfortran/Runtime-Options.html 12542 5. https://gcc.gnu.org/wiki/Statically_linking_libgcj 12543 6. https://gcc.gnu.org/onlinedocs/ 12544 7. mailto:gcc-help (a] gcc.gnu.org 12545 8. mailto:gcc (a] gcc.gnu.org 12546 9. https://gcc.gnu.org/lists.html 12547 10. https://www.fsf.org/ 12548 11. https://gcc.gnu.org/about.html 12549 12. http://validator.w3.org/check/referer 12550 ====================================================================== 12551 http://gcc.gnu.org/gcc-4.1/index.html 12552 GCC 4.1 Release Series 12553 12554 (This release series is no longer supported.) 12555 12556 February 13, 2007 12557 12558 The [1]GNU project and the GCC developers are pleased to announce the 12559 release of GCC 4.1.2. 12560 12561 This release is a bug-fix release, containing fixes for regressions in 12562 GCC 4.1.1 relative to previous releases of GCC. 12563 12564 Release History 12565 12566 GCC 4.1.2 12567 February 13, 2007 ([2]changes) 12568 12569 GCC 4.1.1 12570 May 24, 2006 ([3]changes) 12571 12572 GCC 4.1.0 12573 February 28, 2006 ([4]changes) 12574 12575 References and Acknowledgements 12576 12577 GCC used to stand for the GNU C Compiler, but since the compiler 12578 supports several other languages aside from C, it now stands for the 12579 GNU Compiler Collection. 12580 12581 A list of [5]successful builds is updated as new information becomes 12582 available. 12583 12584 The GCC developers would like to thank the numerous people that have 12585 contributed new features, improvements, bug fixes, and other changes as 12586 well as test results to GCC. This [6]amazing group of volunteers is 12587 what makes GCC successful. 12588 12589 For additional information about GCC please refer to the [7]GCC project 12590 web site or contact the [8]GCC development mailing list. 12591 12592 To obtain GCC please use [9]our mirror sites or [10]our version control 12593 system. 12594 12595 12596 For questions related to the use of GCC, please consult these web 12597 pages and the [11]GCC manuals. If that fails, the 12598 [12]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12599 web pages and the development of GCC are welcome on our developer 12600 list at [13]gcc (a] gcc.gnu.org. All of [14]our lists have public 12601 archives. 12602 12603 Copyright (C) [15]Free Software Foundation, Inc. Verbatim copying and 12604 distribution of this entire article is permitted in any medium, 12605 provided this notice is preserved. 12606 12607 These pages are [16]maintained by the GCC team. Last modified 12608 2021-07-28[17]. 12609 12610 References 12611 12612 1. http://www.gnu.org/ 12613 2. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 12614 3. http://gcc.gnu.org/gcc-4.1/changes.html 12615 4. http://gcc.gnu.org/gcc-4.1/changes.html 12616 5. http://gcc.gnu.org/gcc-4.1/buildstat.html 12617 6. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 12618 7. http://gcc.gnu.org/index.html 12619 8. mailto:gcc (a] gcc.gnu.org 12620 9. http://gcc.gnu.org/mirrors.html 12621 10. http://gcc.gnu.org/git.html 12622 11. https://gcc.gnu.org/onlinedocs/ 12623 12. mailto:gcc-help (a] gcc.gnu.org 12624 13. mailto:gcc (a] gcc.gnu.org 12625 14. https://gcc.gnu.org/lists.html 12626 15. https://www.fsf.org/ 12627 16. https://gcc.gnu.org/about.html 12628 17. http://validator.w3.org/check/referer 12629 ====================================================================== 12630 http://gcc.gnu.org/gcc-4.1/changes.html 12631 GCC 4.1 Release Series 12632 Changes, New Features, and Fixes 12633 12634 The latest release in the 4.1 release series is [1]GCC 4.1.2. 12635 12636 Caveats 12637 12638 General Optimizer Improvements 12639 12640 * GCC now has infrastructure for inter-procedural optimizations and 12641 the following inter-procedural optimizations are implemented: 12642 + Profile guided inlining. When doing profile feedback guided 12643 optimization, GCC can now use the profile to make better 12644 informed decisions on whether inlining of a function is 12645 profitable or not. This means that GCC will no longer inline 12646 functions at call sites that are not executed very often, and 12647 that functions at hot call sites are more likely to be 12648 inlined. 12649 A new parameter min-inline-recursive-probability is also now 12650 available to throttle recursive inlining of functions with 12651 small average recursive depths. 12652 + Discovery of pure and const functions, a form of side-effects 12653 analysis. While older GCC releases could also discover such 12654 special functions, the new IPA-based pass runs earlier so that 12655 the results are available to more optimizers. The pass is also 12656 simply more powerful than the old one. 12657 + Analysis of references to static variables and type escape 12658 analysis, also forms of side-effects analysis. The results of 12659 these passes allow the compiler to be less conservative about 12660 call-clobbered variables and references. This results in more 12661 redundant loads being eliminated and in making static 12662 variables candidates for register promotion. 12663 + Improvement of RTL-based alias analysis. The results of type 12664 escape analysis are fed to the RTL type-based alias analyzer, 12665 allowing it to disambiguate more memory references. 12666 + Interprocedural constant propagation and function versioning. 12667 This pass looks for functions that are always called with the 12668 same constant value for one or more of the function arguments, 12669 and propagates those constants into those functions. 12670 + GCC will now eliminate static variables whose usage was 12671 optimized out. 12672 + -fwhole-program --combine can now be used to make all 12673 functions in program static allowing whole program 12674 optimization. As an exception, the main function and all 12675 functions marked with the new externally_visible attribute are 12676 kept global so that programs can link with runtime libraries. 12677 * GCC can now do a form of partial dead code elimination (PDCE) that 12678 allows code motion of expressions to the paths where the result of 12679 the expression is actually needed. This is not always a win, so the 12680 pass has been limited to only consider profitable cases. Here is an 12681 example: 12682 int foo (int *, int *); 12683 int 12684 bar (int d) 12685 { 12686 int a, b, c; 12687 b = d + 1; 12688 c = d + 2; 12689 a = b + c; 12690 if (d) 12691 { 12692 foo (&b, &c); 12693 a = b + c; 12694 } 12695 printf ("%d\n", a); 12696 } 12697 12698 The a = b + c can be sunk to right before the printf. Normal code 12699 sinking will not do this, it will sink the first one above into the 12700 else-branch of the conditional jump, which still gives you two 12701 copies of the code. 12702 * GCC now has a value range propagation pass. This allows the 12703 compiler to eliminate bounds checks and branches. The results of 12704 the pass can also be used to accurately compute branch 12705 probabilities. 12706 * The pass to convert PHI nodes to straight-line code (a form of 12707 if-conversion for GIMPLE) has been improved significantly. The two 12708 most significant improvements are an improved algorithm to 12709 determine the order in which the PHI nodes are considered, and an 12710 improvement that allow the pass to consider if-conversions of basic 12711 blocks with more than two predecessors. 12712 * Alias analysis improvements. GCC can now differentiate between 12713 different fields of structures in Tree-SSA's virtual operands form. 12714 This lets stores/loads from non-overlapping structure fields not 12715 conflict. A new algorithm to compute points-to sets was contributed 12716 that can allows GCC to see now that p->a and p->b, where p is a 12717 pointer to a structure, can never point to the same field. 12718 * Various enhancements to auto-vectorization: 12719 + Incrementally preserve SSA form when vectorizing. 12720 + Incrementally preserve loop-closed form when vectorizing. 12721 + Improvements to peeling for alignment: generate better code 12722 when the misalignment of an access is known at compile time, 12723 or when different accesses are known to have the same 12724 misalignment, even if the misalignment amount itself is 12725 unknown. 12726 + Consider dependence distance in the vectorizer. 12727 + Externalize generic parts of data reference analysis to make 12728 this analysis available to other passes. 12729 + Vectorization of conditional code. 12730 + Reduction support. 12731 * GCC can now partition functions in sections of hot and cold code. 12732 This can significantly improve performance due to better 12733 instruction cache locality. This feature works best together with 12734 profile feedback driven optimization. 12735 * A new pass to avoid saving of unneeded arguments to the stack in 12736 vararg functions if the compiler can prove that they will not be 12737 needed. 12738 * Transition of basic block profiling to tree level implementation 12739 has been completed. The new implementation should be considerably 12740 more reliable (hopefully avoiding profile mismatch errors when 12741 using -fprofile-use or -fbranch-probabilities) and can be used to 12742 drive higher level optimizations, such as inlining. 12743 The -ftree-based-profiling command-line option was removed and 12744 -fprofile-use now implies disabling old RTL level loop optimizer 12745 (-fno-loop-optimize). Speculative prefetching optimization 12746 (originally enabled by -fspeculative-prefetching) was removed. 12747 12748 New Languages and Language specific improvements 12749 12750 C and Objective-C 12751 12752 * The old Bison-based C and Objective-C parser has been replaced by a 12753 new, faster hand-written recursive-descent parser. 12754 12755 Ada 12756 12757 * The build infrastructure for the Ada runtime library and tools has 12758 been changed to be better integrated with the rest of the build 12759 infrastructure of GCC. This should make doing cross builds of Ada a 12760 bit easier. 12761 12762 C++ 12763 12764 * ARM-style name-injection of friend declarations is no longer the 12765 default. For example: 12766 struct S { 12767 friend void f(); 12768 }; 12769 12770 void g() { f(); } 12771 will not be accepted; instead a declaration of f will need to be 12772 present outside of the scope of S. The new -ffriend-injection 12773 option will enable the old behavior. 12774 * The (undocumented) extension which permitted templates with default 12775 arguments to be bound to template template parameters with fewer 12776 parameters has been deprecated, and will be removed in the next 12777 major release of G++. For example: 12778 template <template <typename> class C> 12779 void f(C<double>) {} 12780 12781 template <typename T, typename U = int> 12782 struct S {}; 12783 12784 template void f(S<double>); 12785 12786 makes use of the deprecated extension. The reason this code is not 12787 valid ISO C++ is that S is a template with two parameters; 12788 therefore, it cannot be bound to C which has only one parameter. 12789 12790 Runtime Library (libstdc++) 12791 12792 * Optimization work: 12793 + A new implementation of std::search_n is provided, better 12794 performing in case of random access iterators. 12795 + Added further efficient specializations of istream functions, 12796 i.e., character array and string extractors. 12797 + Other smaller improvements throughout. 12798 * Policy-based associative containers, designed for high-performance, 12799 flexibility and semantic safety are delivered in ext/pb_assoc. 12800 * A versatile string class, __gnu_cxx::__versa_string, providing 12801 facilities conforming to the standard requirements for 12802 basic_string, is delivered in <ext/vstring.h>. In particular: 12803 + Two base classes are provided: the default one avoids 12804 reference counting and is optimized for short strings; the 12805 alternate one, still uses it while improving in a few low 12806 level areas (e.g., alignment). See vstring_fwd.h for some 12807 useful typedefs. 12808 + Various algorithms have been rewritten (e.g., replace), the 12809 code streamlined and simple optimizations added. 12810 + Option 3 of DR 431 is implemented for both available bases, 12811 thus improving the support for stateful allocators. 12812 * As usual, many bugs have been fixed (e.g., libstdc++/13583, 12813 libstdc++/23953) and LWG resolutions put into effect for the first 12814 time (e.g., DR 280, DR 464, N1780 recommendations for DR 233, TR1 12815 Issue 6.19). The implementation status of TR1 is now tracked in the 12816 docs in tr1.html. 12817 12818 Objective-C++ 12819 12820 * A new language front end for Objective-C++ has been added. This 12821 language allows users to mix the object oriented features of 12822 Objective-C with those of C++. 12823 12824 Java (GCJ) 12825 12826 * Core library (libgcj) updates based on GNU Classpath 0.15 - 0.19 12827 features (plus some 0.20 bug-fixes) 12828 + Networking 12829 o The java.net.HttpURLConnection implementation no longer 12830 buffers the entire response body in memory. This means 12831 that response bodies larger than available memory can now 12832 be handled. 12833 + (N)IO 12834 o NIO FileChannel.map implementation, fast bulk put 12835 implementation for DirectByteBuffer (speeds up this 12836 method 10x). 12837 o FileChannel.lock() and FileChannel.force() implemented. 12838 + XML 12839 o gnu.xml fix for nodes created outside a namespace 12840 context. 12841 o Add support for output indenting and 12842 cdata-section-elements output instruction in 12843 xml.transform. 12844 o xml.xpath corrections for cases where elements/attributes 12845 might have been created in non-namespace-aware mode. 12846 Corrections to handling of XSL variables and minor 12847 conformance updates. 12848 + AWT 12849 o GNU JAWT implementation, the AWT Native Interface, which 12850 allows direct access to native screen resources from 12851 within a Canvas's paint method. GNU Classpath Examples 12852 comes with a Demo, see libjava/classpath/examples/README. 12853 o awt.datatransfer updated to 1.5 with support for 12854 FlavorEvents. The gtk+ awt peers now allow copy/paste of 12855 text, images, URIs/files and serialized objects with 12856 other applications and tracking clipboard change events 12857 with gtk+ 2.6 (for gtk+ 2.4 only text and serialized 12858 objects are supported). A GNU Classpath Examples 12859 datatransfer Demo was added to show the new 12860 functionality. 12861 o Split gtk+ awt peers event handling in two threads and 12862 improve gdk lock handling (solves several awt lock ups). 12863 o Speed up awt Image loading. 12864 o Better gtk+ scrollbar peer implementation when using gtk+ 12865 >= 2.6. 12866 o Handle image loading errors correctly for gdkpixbuf and 12867 MediaTracker. 12868 o Better handle GDK lock. Properly prefix gtkpeer native 12869 functions (cp_gtk). 12870 o GdkGraphics2D has been updated to use Cairo 0.5.x or 12871 higher. 12872 o BufferedImage and GtkImage rewrites. All image drawing 12873 operations should now work correctly (flipping requires 12874 gtk+ >= 2.6) 12875 o When gtk+ 2.6 or higher is installed the default log 12876 handler will produce stack traces whenever a WARNING, 12877 CRITICAL or ERROR message is produced. 12878 + Free Swing 12879 o The RepaintManager has been reworked for more efficient 12880 painting, especially for large GUIs. 12881 o The layout manager OverlayLayout has been implemented, 12882 the BoxLayout has been rewritten to make use of the 12883 SizeRequirements utility class and caching for more 12884 efficient layout. 12885 o Improved accessibility support. 12886 o Significant progress has been made in the implementation 12887 of the javax.swing.plaf.metal package, with most UI 12888 delegates in a working state now. Please test this with 12889 your own applications and provide feedback that will help 12890 us to improve this package. 12891 o The GUI demo (gnu.classpath.examples.swing.Demo) has been 12892 extended to highlight various features in our Free Swing 12893 implementation. And it includes a look and feel switcher 12894 for Metal (default), Ocean and GNU themes. 12895 o The javax.swing.plaf.multi package is now implemented. 12896 o Editing and several key actions for JTree and JTable were 12897 implemented. 12898 o Lots of icons and look and feel improvements for Free 12899 Swing basic and metal themes were added. Try running the 12900 GNU Classpath Swing Demo in examples 12901 (gnu.classpath.examples.swing.Demo) with: 12902 -Dswing.defaultlaf=javax.swing.plaf.basic.BasicLookAndFee 12903 l or 12904 -Dswing.defaultlaf=javax.swing.plaf.metal.MetalLookAndFee 12905 l 12906 o Start of styled text capabilites for java.swing.text. 12907 o DefaultMutableTreeNode pre-order, post-order, depth-first 12908 and breadth-first traversal enumerations implemented. 12909 o JInternalFrame colors and titlebar draw properly. 12910 o JTree is working up to par (icons, selection and keyboard 12911 traversal). 12912 o JMenus were made more compatible in visual and 12913 programmatic behavior. 12914 o JTable changeSelection and multiple selections 12915 implemented. 12916 o JButton and JToggleButton change states work properly 12917 now. 12918 o JFileChooser fixes. 12919 o revalidate() and repaint() fixes which make Free Swing 12920 much more responsive. 12921 o MetalIconFactory implemented. 12922 o Free Swing Top-Level Compatibility. JFrame, JDialog, 12923 JApplet, JInternalFrame, and JWindow are now 1.5 12924 compatible in the sense that you can call add() and 12925 setLayout() directly on them, which will have the same 12926 effect as calling getContentPane().add() and 12927 getContentPane().setLayout(). 12928 o The JTree interface has been completed. JTrees now 12929 recognizes mouse clicks and selections work. 12930 o BoxLayout works properly now. 12931 o Fixed GrayFilter to actually work. 12932 o Metal SplitPane implemented. 12933 o Lots of Free Swing text and editor stuff work now. 12934 + Free RMI and Corba 12935 o Andrew Watson, Vice President and Technical Director of 12936 the Object Management Group, has officially assigned us 12937 20 bit Vendor Minor Code Id: 0x47430 ("GC") that will 12938 mark remote classpath-specific system exceptions. 12939 Obtaining the VMCID means that GNU Classpath now is a 12940 recogniseable type of node in a highly interoperable 12941 CORBA world. 12942 o GNU Classpath now includes the first working draft to 12943 support the RMI over IIOP protocol. The current 12944 implementation is capable of remote invocations, 12945 transferring various Serializables and Externalizables 12946 via RMI-IIOP protocol. It can flatten graphs and, at 12947 least for the simple cases, is interoperable with 1.5 12948 JDKs. 12949 o org.omg.PortableInterceptor and related functionality in 12950 other packages is now implemented: 12951 # The sever and client interceptors work as required 12952 since 1.4. 12953 # The IOR interceptor works as needed for 1.5. 12954 o The org.omg.DynamicAny package is completed and passes 12955 the prepared tests. 12956 o The Portable Object Adapter should now support the output 12957 of the recent IDL to java compilers. These compilers now 12958 generate servants and not CORBA objects as before, making 12959 the output depend on the existing POA implementation. 12960 Completing POA means that such code can already be tried 12961 to run on Classpath. Our POA is tested for the following 12962 usager scenarios: 12963 # POA converts servant to the CORBA object. 12964 # Servant provides to the CORBA object. 12965 # POA activates new CORBA object with the given Object 12966 Id (byte array) that is later accessible for the 12967 servant. 12968 # During the first call, the ServantActivator provides 12969 servant for this and all subsequent calls on the 12970 current object. 12971 # During each call, the ServantLocator provides 12972 servant for this call only. 12973 # ServantLocator or ServantActivator forwards call to 12974 another server. 12975 # POA has a single servant, responsible for all 12976 objects. 12977 # POA has a default servant, but some objects are 12978 explicitly connected to they specific servants. 12979 The POA is verified using tests from the former 12980 cost.omg.org. 12981 o The CORBA implementation is now a working prototype that 12982 should support features up to 1.3 inclusive. We invite 12983 groups writing CORBA dependent applications to try 12984 Classpath implementation, reporting any possible bugs. 12985 The CORBA prototype is interoperable with Sun's 12986 implementation v 1.4, transferring object references, 12987 primitive types, narrow and wide strings, arrays, 12988 structures, trees, abstract interfaces and value types 12989 (feature of CORBA 2.3) between these two platforms. 12990 Remote exceptions are transferred and handled correctly. 12991 The stringified object references (IORs) from various 12992 sources are parsed as required. The transient (for 12993 current session) and permanent (till jre restart) 12994 redirections work. Both Little and Big Endian encoded 12995 messages are accepted. The implementation is verified 12996 using tests from the former cost.omg.org. The current 12997 release includes working examples (see the examples 12998 directory), demonstrating the client-server 12999 communication, using either CORBA Request or IDL-based 13000 stub (usually generated by a IDL to java compiler). These 13001 examples also show how to use the Classpath CORBA naming 13002 service. The IDL to java compiler is not yet written, but 13003 as our library must be compatible, it naturally accepts 13004 the output of other idlj implementations. 13005 + Misc 13006 o Updated TimeZone data against Olson tzdata2005l. 13007 o Make zip and jar packages UTF-8 clean. 13008 o "native" code builds and compiles (warning free) on 13009 Darwin and Solaris. 13010 o java.util.logging.FileHandler now rotates files. 13011 o Start of a generic JDWP framework in gnu/classpath/jdwp. 13012 This is unfinished, but feedback (at classpath (a] gnu.org) 13013 from runtime hackers is greatly appreciated. Although 13014 most of the work is currently being done around gcj/gij 13015 we want this framework to be as VM neutral as possible. 13016 Early design is described in: 13017 [2]https://gcc.gnu.org/ml/java/2005-05/msg00260.html 13018 o QT4 AWT peers, enable by giving configure 13019 --enable-qt-peer. Included, but not ready for production 13020 yet. They are explicitly disabled and not supported. But 13021 if you want to help with the development of these new 13022 features we are interested in feedback. You will have to 13023 explicitly enable them to try them out (and they will 13024 most likely contain bugs). 13025 o Documentation fixes all over the place. See 13026 [3]https://developer.classpath.org/doc/ 13027 13028 New Targets and Target Specific Improvements 13029 13030 IA-32/x86-64 13031 13032 * The x86-64 medium model (that allows building applications whose 13033 data segment exceeds 4GB) was redesigned to match latest ABI draft. 13034 New implementation split large datastructures into separate segment 13035 improving performance of accesses to small datastructures and also 13036 allows linking of small model libraries into medium model programs 13037 as long as the libraries are not accessing the large datastructures 13038 directly. Medium model is also supported in position independent 13039 code now. 13040 The ABI change results in partial incompatibility among medium 13041 model objects. Linking medium model libraries (or objects) compiled 13042 with new compiler into medium model program compiled with older 13043 will likely result in exceeding ranges of relocations. 13044 Binutils 2.16.91 or newer are required for compiling medium model 13045 now. 13046 13047 RS6000 (POWER/PowerPC) 13048 13049 * The AltiVec vector primitives in <altivec.h> are now implemented in 13050 a way that puts a smaller burden on the preprocessor, instead 13051 processing the "overloading" in the front ends. This should benefit 13052 compilation speed on AltiVec vector code. 13053 * AltiVec initializers now are generated more efficiently. 13054 * The popcountb instruction available on POWER5 now is generated. 13055 * The floating point round to integer instructions available on 13056 POWER5+ now is generated. 13057 * Floating point divides can be synthesized using the floating point 13058 reciprocal estimate instructions. 13059 * Double precision floating point constants are initialized as single 13060 precision values if they can be represented exactly. 13061 13062 S/390, zSeries and System z9 13063 13064 * Support for the IBM System z9 109 processor has been added. When 13065 using the -march=z9-109 option, the compiler will generate code 13066 making use of instructions provided by the extended immediate 13067 facility. 13068 * Support for 128-bit IEEE floating point has been added. When using 13069 the -mlong-double-128 option, the compiler will map the long double 13070 data type to 128-bit IEEE floating point. Using this option 13071 constitutes an ABI change, and requires glibc support. 13072 * Various changes to improve performance of generated code have been 13073 implemented, including: 13074 + In functions that do not require a literal pool, register %r13 13075 (which is traditionally reserved as literal pool pointer), can 13076 now be freely used for other purposes by the compiler. 13077 + More precise tracking of register use allows the compiler to 13078 generate more efficient function prolog and epilog code in 13079 certain cases. 13080 + The SEARCH STRING, COMPARE LOGICAL STRING, and MOVE STRING 13081 instructions are now used to implement C string functions. 13082 + The MOVE CHARACTER instruction with single byte overlap is now 13083 used to implement the memset function with non-zero fill byte. 13084 + The LOAD ZERO instructions are now used where appropriate. 13085 + The INSERT CHARACTERS UNDER MASK, STORE CHARACTERS UNDER MASK, 13086 and INSERT IMMEDIATE instructions are now used more frequently 13087 to optimize bitfield operations. 13088 + The BRANCH ON COUNT instruction is now used more frequently. 13089 In particular, the fact that a loop contains a subroutine call 13090 no longer prevents the compiler from using this instruction. 13091 + The compiler is now aware that all shift and rotate 13092 instructions implicitly truncate the shift count to six bits. 13093 * Back-end support for the following generic features has been 13094 implemented: 13095 + The full set of [4]built-in functions for atomic memory 13096 access. 13097 + The -fstack-protector feature. 13098 + The optimization pass avoiding unnecessary stores of incoming 13099 argument registers in functions with variable argument list. 13100 13101 SPARC 13102 13103 * The default code model in 64-bit mode has been changed from 13104 Medium/Anywhere to Medium/Middle on Solaris. 13105 * TLS support is disabled by default on Solaris prior to release 10. 13106 It can be enabled on TLS-capable Solaris 9 versions (4/04 release 13107 and later) by specifying --enable-tls at configure time. 13108 13109 MorphoSys 13110 13111 * Support has been added for this new architecture. 13112 13113 Obsolete Systems 13114 13115 Documentation improvements 13116 13117 Other significant improvements 13118 13119 * GCC can now emit code for protecting applications from 13120 stack-smashing attacks. The protection is realized by buffer 13121 overflow detection and reordering of stack variables to avoid 13122 pointer corruption. 13123 * Some built-in functions have been fortified to protect them against 13124 various buffer overflow (and format string) vulnerabilities. 13125 Compared to the mudflap bounds checking feature, the safe builtins 13126 have far smaller overhead. This means that programs built using 13127 safe builtins should not experience any measurable slowdown. 13128 13129 GCC 4.1.2 13130 13131 This is the [5]list of problem reports (PRs) from GCC's bug tracking 13132 system that are known to be fixed in the 4.1.2 release. This list might 13133 not be complete (that is, it is possible that some PRs that have been 13134 fixed are not listed here). 13135 13136 When generating code for a shared library, GCC now recognizes that 13137 global functions may be replaced when the program runs. Therefore, it 13138 is now more conservative in deducing information from the bodies of 13139 functions. For example, in this example: 13140 void f() {} 13141 void g() { 13142 try { f(); } 13143 catch (...) { 13144 cout << "Exception"; 13145 } 13146 } 13147 13148 G++ would previously have optimized away the catch clause, since it 13149 would have concluded that f cannot throw exceptions. Because users may 13150 replace f with another function in the main body of the program, this 13151 optimization is unsafe, and is no longer performed. If you wish G++ to 13152 continue to optimize as before, you must add a throw() clause to the 13153 declaration of f to make clear that it does not throw exceptions. 13154 13155 13156 For questions related to the use of GCC, please consult these web 13157 pages and the [6]GCC manuals. If that fails, the 13158 [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13159 web pages and the development of GCC are welcome on our developer 13160 list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives. 13161 13162 Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and 13163 distribution of this entire article is permitted in any medium, 13164 provided this notice is preserved. 13165 13166 These pages are [11]maintained by the GCC team. Last modified 13167 2021-10-18[12]. 13168 13169 References 13170 13171 1. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 13172 2. https://gcc.gnu.org/ml/java/2005-05/msg00260.html 13173 3. https://developer.classpath.org/doc/ 13174 4. https://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html 13175 5. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.1.2 13176 6. https://gcc.gnu.org/onlinedocs/ 13177 7. mailto:gcc-help (a] gcc.gnu.org 13178 8. mailto:gcc (a] gcc.gnu.org 13179 9. https://gcc.gnu.org/lists.html 13180 10. https://www.fsf.org/ 13181 11. https://gcc.gnu.org/about.html 13182 12. http://validator.w3.org/check/referer 13183 ====================================================================== 13184 http://gcc.gnu.org/gcc-4.0/index.html 13185 GCC 4.0 Release Series 13186 13187 (This release series is no longer supported.) 13188 13189 January 31, 2007 13190 13191 The [1]GNU project and the GCC developers are pleased to announce the 13192 release of GCC 4.0.4. 13193 13194 This release is a bug-fix release, containing fixes for regressions in 13195 GCC 4.0.3 relative to previous releases of GCC. 13196 13197 Release History 13198 13199 GCC 4.0.4 13200 January 31, 2007 ([2]changes) 13201 13202 GCC 4.0.3 13203 March 10, 2006 ([3]changes) 13204 13205 GCC 4.0.2 13206 September 28, 2005 ([4]changes) 13207 13208 GCC 4.0.1 13209 July 7, 2005 ([5]changes) 13210 13211 GCC 4.0.0 13212 April 20, 2005 ([6]changes) 13213 13214 References and Acknowledgements 13215 13216 GCC used to stand for the GNU C Compiler, but since the compiler 13217 supports several other languages aside from C, it now stands for the 13218 GNU Compiler Collection. 13219 13220 A list of [7]successful builds is updated as new information becomes 13221 available. 13222 13223 The GCC developers would like to thank the numerous people that have 13224 contributed new features, improvements, bug fixes, and other changes as 13225 well as test results to GCC. This [8]amazing group of volunteers is 13226 what makes GCC successful. 13227 13228 For additional information about GCC please refer to the [9]GCC project 13229 web site or contact the [10]GCC development mailing list. 13230 13231 To obtain GCC please use [11]our mirror sites, or [12]our version 13232 control system. 13233 13234 13235 For questions related to the use of GCC, please consult these web 13236 pages and the [13]GCC manuals. If that fails, the 13237 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13238 web pages and the development of GCC are welcome on our developer 13239 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 13240 archives. 13241 13242 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 13243 distribution of this entire article is permitted in any medium, 13244 provided this notice is preserved. 13245 13246 These pages are [18]maintained by the GCC team. Last modified 13247 2021-07-28[19]. 13248 13249 References 13250 13251 1. http://www.gnu.org/ 13252 2. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 13253 3. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.3 13254 4. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.2 13255 5. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.1 13256 6. http://gcc.gnu.org/gcc-4.0/changes.html 13257 7. http://gcc.gnu.org/gcc-4.0/buildstat.html 13258 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13259 9. http://gcc.gnu.org/index.html 13260 10. mailto:gcc (a] gcc.gnu.org 13261 11. http://gcc.gnu.org/mirrors.html 13262 12. http://gcc.gnu.org/git.html 13263 13. https://gcc.gnu.org/onlinedocs/ 13264 14. mailto:gcc-help (a] gcc.gnu.org 13265 15. mailto:gcc (a] gcc.gnu.org 13266 16. https://gcc.gnu.org/lists.html 13267 17. https://www.fsf.org/ 13268 18. https://gcc.gnu.org/about.html 13269 19. http://validator.w3.org/check/referer 13270 ====================================================================== 13271 http://gcc.gnu.org/gcc-4.0/changes.html 13272 GCC 4.0 Release Series 13273 Changes, New Features, and Fixes 13274 13275 The latest release in the 4.0 release series is [1]GCC 4.0.4. 13276 13277 Caveats 13278 13279 * GCC now generates location lists by default when compiling with 13280 debug info and optimization. 13281 + GDB 6.0 and older crashes when it sees location lists. GDB 6.1 13282 or later is needed to debug binaries containing location 13283 lists. 13284 + When you are trying to view a value of a variable in a part of 13285 a function where it has no location (for example when the 13286 variable is no longer used and thus its location was used for 13287 something else) GDB will say that it is not available. 13288 You can disable generating location lists by -fno-var-tracking. 13289 * GCC no longer accepts the -fwritable-strings option. Use named 13290 character arrays when you need a writable string. 13291 * The options -freduce-all-givs and -fmove-all-movables have been 13292 discontinued. They were used to circumvent a shortcoming in the 13293 heuristics of the old loop optimization code with respect to common 13294 Fortran constructs. The new (tree) loop optimizer works differently 13295 and doesn't need those work-arounds. 13296 * The graph-coloring register allocator, formerly enabled by the 13297 option -fnew-ra, has been discontinued. 13298 * -I- has been deprecated. -iquote is meant to replace the need for 13299 this option. 13300 * The MIPS -membedded-pic and -mrnames options have been removed. 13301 * All MIPS targets now require the GNU assembler. In particular, IRIX 13302 configurations can no longer use the MIPSpro assemblers, although 13303 they do still support the MIPSpro linkers. 13304 * The SPARC option -mflat has been removed. 13305 * English-language diagnostic messages will now use Unicode quotation 13306 marks in UTF-8 locales. (Non-English messages already used the 13307 quotes appropriate for the language in previous releases.) If your 13308 terminal does not support UTF-8 but you are using a UTF-8 locale 13309 (such locales are the default on many GNU/Linux systems) then you 13310 should set LC_CTYPE=C in the environment to disable that locale. 13311 Programs that parse diagnostics and expect plain ASCII 13312 English-language messages should set LC_ALL=C. See [2]Markus Kuhn's 13313 explanation of Unicode quotation marks for more information. 13314 * The specs file is no longer installed on most platforms. Most users 13315 will be totally unaffected. However, if you are accustomed to 13316 editing the specs file yourself, you will now have to use the 13317 -dumpspecs option to generate the specs file, and then edit the 13318 resulting file. 13319 13320 General Optimizer Improvements 13321 13322 * The [3]tree ssa branch has been merged. This merge has brought in a 13323 completely new optimization framework based on a higher level 13324 intermediate representation than the existing RTL representation. 13325 Numerous new code transformations based on the new framework are 13326 available in GCC 4.0, including: 13327 + Scalar replacement of aggregates 13328 + Constant propagation 13329 + Value range propagation 13330 + Partial redundancy elimination 13331 + Load and store motion 13332 + Strength reduction 13333 + Dead store elimination 13334 + Dead and unreachable code elimination 13335 + [4]Autovectorization 13336 + Loop interchange 13337 + Tail recursion by accumulation 13338 Many of these passes outperform their counterparts from previous 13339 GCC releases. 13340 * [5]Swing Modulo Scheduling (SMS). An RTL level instruction 13341 scheduling optimization intended for loops that perform heavy 13342 computations. 13343 13344 New Languages and Language specific improvements 13345 13346 C family 13347 13348 * The sentinel attribute has been added to GCC. This function 13349 attribute allows GCC to warn when variadic functions such as execl 13350 are not NULL terminated. See the GCC manual for a complete 13351 description of its behavior. 13352 * Given __attribute__((alias("target"))) it is now an error if target 13353 is not a symbol, defined in the same translation unit. This also 13354 applies to aliases created by #pragma weak alias=target. This is 13355 because it's meaningless to define an alias to an undefined symbol. 13356 On Solaris, the native assembler would have caught this error, but 13357 GNU as does not. 13358 13359 C and Objective-C 13360 13361 * The -Wstrict-aliasing=2 option has been added. This warning catches 13362 all unsafe cases, but it may also give a warning for some cases 13363 that are safe. 13364 * The cast-as-lvalue, conditional-expression-as-lvalue and 13365 compound-expression-as-lvalue extensions, which were deprecated in 13366 3.3.4 and 3.4, have been removed. 13367 * The -fwritable-strings option, which was deprecated in 3.4, has 13368 been removed. 13369 * #pragma pack() semantics have been brought closer to those used by 13370 other compilers. This also applies to C++. 13371 * Taking the address of a variable with register storage is invalid 13372 in C. GCC now issues an error instead of a warning. 13373 * Arrays of incomplete element type are invalid in C. GCC now issues 13374 an error for such arrays. Declarations such as extern struct s x[]; 13375 (where struct s has not been defined) can be moved after the 13376 definition of struct s. Function parameters declared as arrays of 13377 incomplete type can instead be declared as pointers. 13378 13379 C++ 13380 13381 * When compiling without optimizations (-O0), the C++ front end is 13382 much faster than in any previous versions of GCC. Independent 13383 testers have measured speed-ups up to 25% in real-world production 13384 code, compared to the 3.4 family (which was already the fastest 13385 version to date). Upgrading from older versions might show even 13386 bigger improvements. 13387 * ELF visibility attributes can now be applied to a class type, so 13388 that it affects every member function of a class at once, without 13389 having to specify each individually: 13390 class __attribute__ ((visibility("hidden"))) Foo 13391 { 13392 int foo1(); 13393 void foo2(); 13394 }; 13395 The syntax is deliberately similar to the __declspec() system used 13396 by Microsoft Windows based compilers, allowing cross-platform 13397 projects to easily reuse their existing macro system for denoting 13398 exports and imports. By explicitly marking internal classes never 13399 used outside a binary as hidden, one can completely avoid PLT 13400 indirection overheads during their usage by the compiler. You can 13401 find out more about the advantages of this at 13402 [6]https://www.akkadia.org/drepper/dsohowto.pdf 13403 * The -fvisibility-inlines-hidden option has been added which marks 13404 all inlineable functions as having hidden ELF visibility, thus 13405 removing their symbol and typeinfo from the exported symbol table 13406 of the output ELF binary. Using this option can reduce the exported 13407 symbol count of template-heavy code by up to 40% with no code 13408 change at all, thus notably improving link and load times for the 13409 binary as well as a reduction in size of up to 10%. Also, check the 13410 new [7]-fvisibility option. 13411 * The compiler now uses the library interface specified by the [8]C++ 13412 ABI for thread-safe initialization of function-scope static 13413 variables. Most users should leave this alone, but embedded 13414 programmers may want to disable this by specifying 13415 -fno-threadsafe-statics for a small savings in code size. 13416 * Taking the address of an explicit register variable is no longer 13417 supported. Note that C++ allows taking the address of variables 13418 with register storage so this will continue to compile with a 13419 warning. For example, assuming that r0 is a machine register: 13420 register int foo asm ("r0"); 13421 register int bar; 13422 &foo; // error, no longer accepted 13423 &bar; // OK, with a warning 13424 * G++ has an undocumented extension to virtual function covariancy 13425 rules that allowed the overrider to return a type that was 13426 implicitly convertable to the overridden function's return type. 13427 For instance a function returning void * could be overridden by a 13428 function returning T *. This is now deprecated and will be removed 13429 in a future release. 13430 * The G++ minimum and maximum operators (<? and >?) and their 13431 compound forms (<?=) and >?=) have been deprecated and will be 13432 removed in a future version. Code using these operators should be 13433 modified to use std::min and std::max instead. 13434 * Declaration of nested classes of class templates as friends are 13435 supported: 13436 template <typename T> struct A { 13437 class B {}; 13438 }; 13439 class C { 13440 template <typename T> friend class A<T>::B; 13441 }; 13442 This complements the feature member functions of class templates as 13443 friends introduced in GCC 3.4.0. 13444 * When declaring a friend class using an unqualified name, classes 13445 outside the innermost non-class scope are not searched: 13446 class A; 13447 namespace N { 13448 class B { 13449 friend class A; // Refer to N::A which has not been declared yet 13450 // because name outside namespace N are not searched 13451 friend class ::A; // Refer to ::A 13452 }; 13453 } 13454 Hiding the friend name until declaration is still not implemented. 13455 * Friends of classes defined outside their namespace are correctly 13456 handled: 13457 namespace N { 13458 class A; 13459 } 13460 class N::A { 13461 friend class B; // Refer to N::B in GCC 4.0.0 13462 // but ::B in earlier versions of GCC 13463 }; 13464 13465 Runtime Library (libstdc++) 13466 13467 * Optimization work: 13468 + Added efficient specializations of istream functions for char 13469 and wchar_t. 13470 + Further performance tuning of strings, in particular wrt 13471 single-char append and getline. 13472 + iter_swap - and therefore most of the mutating algorithms - 13473 now makes an unqualified call to swap when the value_type of 13474 the two iterators is the same. 13475 * A large subset of the features in Technical Report 1 (TR1 for 13476 short) is experimentally delivered (i.e., no guarantees about the 13477 implementation are provided. In particular it is not promised that 13478 the library will remain link-compatible when code using TR1 is 13479 used): 13480 + General utilities such as reference_wrapper and shared_ptr. 13481 + Function objects, i.e., result_of, mem_fn, bind, function. 13482 + Support for metaprogramming. 13483 + New containers such as tuple, array, unordered_set, 13484 unordered_map, unordered_multiset, unordered_multimap. 13485 * As usual, many bugs have been fixed and LWG resolutions implemented 13486 for the first time (e.g., DR 409). 13487 13488 Java 13489 13490 * In order to prevent naming conflicts with other implementations of 13491 these tools, some GCJ binaries have been renamed: 13492 + rmic is now grmic, 13493 + rmiregistry is now grmiregistry, and 13494 + jar is now fastjar. 13495 In particular, these names were problematic for the jpackage.org 13496 packaging conventions which install symlinks in /usr/bin that point 13497 to the preferred versions of these tools. 13498 * The -findirect-dispatch argument to the compiler now works and 13499 generates code following a new "binary compatibility" ABI. Code 13500 compiled this way follows the binary compatibility rules of the 13501 Java Language Specification. 13502 * libgcj now has support for using GCJ as a JIT, using the 13503 gnu.gcj.jit family of system properties. 13504 * libgcj can now find a shared library corresponding to the bytecode 13505 representation of a class. See the documentation for the new 13506 gcj-dbtool program, and the new gnu.gcj.precompiled.db.path system 13507 property. 13508 * There have been many improvements to the class library. Here are 13509 some highlights: 13510 + Much more of AWT and Swing exist. 13511 + Many new packages and classes were added, including 13512 java.util.regex, java.net.URI, javax.crypto, 13513 javax.crypto.interfaces, javax.crypto.spec, javax.net, 13514 javax.net.ssl, javax.security.auth, 13515 javax.security.auth.callback, javax.security.auth.login, 13516 javax.security.auth.x500, javax.security.sasl, org.ietf.jgss, 13517 javax.imageio, javax.imageio.event, javax.imageio.spi, 13518 javax.print, javax.print.attribute, 13519 javax.print.attribute.standard, javax.print.event, and 13520 javax.xml 13521 + Updated SAX and DOM, and imported GNU JAXP 13522 13523 Fortran 13524 13525 * A new [9]Fortran front end has replaced the aging GNU Fortran 77 13526 front end. The new front end supports Fortran 90 and Fortran 95. It 13527 may not yet be as stable as the old Fortran front end. 13528 13529 Ada 13530 13531 * Ada (with tasking and Zero Cost Exceptions) is now available on 13532 many more targets, including but not limited to: alpha-linux, 13533 hppa-hpux, hppa-linux, powerpc-darwin, powerpc-linux, s390-linux, 13534 s390x-linux, sparc-linux. 13535 * Some of the new Ada 2005 features are now implemented like 13536 Wide_Wide_Character and Ada.Containers. 13537 * Many bugs have been fixed, tools and documentation improved. 13538 * To compile Ada from the sources, install an older working Ada 13539 compiler and then use --enable-languages=ada at configuration time, 13540 since the Ada front end is not currently activated by default. See 13541 the [10]Installing GCC for details. 13542 13543 New Targets and Target Specific Improvements 13544 13545 H8/300 13546 13547 * The frame layout has changed. In the new layout, the prologue of a 13548 function first saves registers and then allocate space for locals, 13549 resulting in an 1% improvement on code size. 13550 13551 IA-32/x86-64 (AMD64) 13552 13553 * The acos, asin, drem, exp10, exp2, expm1, fmod, ilogb, log10, 13554 log1p, log2, logb and tan mathematical builtins (and their float 13555 and long double variants) are now implemented as inline x87 13556 intrinsics when using -ffast-math. 13557 * The ceil, floor, nearbyint, rint and trunc mathematical builtins 13558 (and their float and long double variants) are now implemented as 13559 inline x87 intrinsics when using -ffast-math. 13560 * The x87's fsincos instruction is now used automatically with 13561 -ffast-math when calculating both the sin and cos of the same 13562 argument. 13563 * Instruction selection for multiplication and division by constants 13564 has been improved. 13565 13566 IA-64 13567 13568 * Floating point division, integer division and sqrt are now inlined, 13569 resulting in significant performance improvements on some codes. 13570 13571 MIPS 13572 13573 * Division by zero checks now use conditional traps if the target 13574 processor supports them. This decreases code size by one word per 13575 division operation. The old behavior (branch and break) can be 13576 obtained either at configure time by passing --with-divide=breaks 13577 to configure or at runtime by passing -mdivide-breaks to GCC. 13578 * Support for MIPS64 paired-single instructions has been added. It is 13579 enabled by -mpaired-single and can be accessed using both the 13580 target-independent vector extensions and new MIPS-specific built-in 13581 functions. 13582 * Support for the MIPS-3D ASE has been added. It is enabled by 13583 -mips3d and provides new MIPS-3D-specific built-in functions. 13584 * The -mexplicit-relocs option now supports static n64 code (as is 13585 used, for example, in 64-bit linux kernels). -mexplicit-relocs 13586 should now be feature-complete and is enabled by default when GCC 13587 is configured to use a compatible assembler. 13588 * Support for the NEC VR4130 series has been added. This support 13589 includes the use of VR-specific instructions and a new VR4130 13590 scheduler. Full VR4130 support can be selected with -march=vr4130 13591 while code for any ISA can be tuned for the VR4130 using 13592 -mtune=vr4130. There is also a new -mvr4130-align option that 13593 produces better schedules at the cost of increased code size. 13594 * Support for the Broadcom SB-1 has been extended. There is now an 13595 SB-1 scheduler as well as support for the SB-1-specific 13596 paired-single instructions. Full SB-1 support can be selected with 13597 -march=sb1 while code for any ISA can be optimized for the SB-1 13598 using -mtune=sb1. 13599 * The compiler can now work around errata in R4000, R4400, VR4120 and 13600 VR4130 processors. These workarounds are enabled by -mfix-r4000, 13601 -mfix-r4400, -mfix-vr4120 and -mfix-vr4130 respectively. The VR4120 13602 and VR4130 workarounds need binutils 2.16 or above. 13603 * IRIX shared libraries are now installed into the standard library 13604 directories: o32 libraries go into lib/, n32 libraries go into 13605 lib32/ and n64 libraries go into lib64/. 13606 * The compiler supports a new -msym32 option. It can be used to 13607 optimize n64 code in which all symbols are known to have 32-bit 13608 values. 13609 13610 S/390 and zSeries 13611 13612 * New command-line options help to generate code intended to run in 13613 an environment where stack space is restricted, e.g. Linux kernel 13614 code: 13615 + -mwarn-framesize and -mwarn-dynamicstack trigger compile-time 13616 warnings for single functions that require large or dynamic 13617 stack frames. 13618 + -mstack-size and -mstack-guard generate code that checks for 13619 stack overflow at run time. 13620 + -mpacked-stack generates code that reduces the stack frame 13621 size of many functions by reusing unneeded parts of the stack 13622 bias area. 13623 * The -msoft-float option now ensures that generated code never 13624 accesses floating point registers. 13625 * The s390x-ibm-tpf target now fully supports C++, including 13626 exceptions and threads. 13627 * Various changes to improve performance of the generated code have 13628 been implemented, including: 13629 + GCC now uses sibling calls where possible. 13630 + Condition code handling has been optimized, allowing GCC to 13631 omit redundant comparisons in certain cases. 13632 + The cost function guiding many optimizations has been refined 13633 to more accurately represent the z900 and z990 processors. 13634 + The ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL WITH BORROW 13635 instructions are now used to avoid conditional branches in 13636 certain cases. 13637 + The back end now uses the LEGITIMIZE_RELOAD_ADDRESS feature to 13638 optimize address arithmetic required to access large stack 13639 frames. 13640 + GCC now makes more efficient use of memory-to-memory type 13641 instructions (MVC, CLC, ...). 13642 + More precise tracking of special register use allows better 13643 instruction scheduling, in particular of the function prologue 13644 and epilogue sequences. 13645 + The Java front end now generates inline code to implement 13646 integer division, instead of calling library routines. 13647 13648 SPARC 13649 13650 * The options -mv8, -msparclite, -mcypress, -msupersparc, -mf930 and 13651 -mf934 have been removed. They have been replaced with -mcpu=xxx. 13652 * The internal model used to estimate the relative cost of each 13653 instruction has been updated. It is expected to give better results 13654 on recent UltraSPARC processors. 13655 * Code generation for function prologues and epilogues has been 13656 improved, resulting in better scheduling and allowing multiple exit 13657 points in functions. 13658 * Support for Sun's Visual Instruction Set (VIS) has been enhanced. 13659 It is enabled by -mvis and provides new built-in functions for VIS 13660 instructions on UltraSPARC processors. 13661 * The option -mapp-regs has been turned on by default on Solaris too. 13662 13663 NetWare 13664 13665 * Novell NetWare (on ix86, no other hardware platform was ever really 13666 supported by this OS) has been re-enabled and the ABI supported by 13667 GCC has been brought into sync with that of MetroWerks CodeWarrior 13668 (the ABI previously supported was that of some Unix systems, which 13669 NetWare never tried to support). 13670 13671 Obsolete Systems 13672 13673 Support for a number of older systems has been declared obsolete in GCC 13674 4.0. Unless there is activity to revive them, the next release of GCC 13675 will have their sources permanently removed. 13676 13677 All GCC ports for the following processor architectures have been 13678 declared obsolete: 13679 * Intel i860 13680 * Ubicom IP2022 13681 * National Semiconductor NS32K (ns32k) 13682 * Texas Instruments TMS320C[34]x 13683 13684 Also, those for some individual systems have been obsoleted: 13685 * SPARC family 13686 + SPARClite-based systems (sparclite-*-coff, sparclite-*-elf, 13687 sparc86x-*-elf) 13688 + OpenBSD 32-bit (sparc-*-openbsd*) 13689 13690 Documentation improvements 13691 13692 Other significant improvements 13693 13694 * Location lists are now generated by default when compiling with 13695 debug info and optimization. Location lists provide more accurate 13696 debug info about locations of variables and they allow debugging 13697 code compiled with -fomit-frame-pointer. 13698 * The -fvisibility option has been added which allows the default ELF 13699 visibility of all symbols to be set per compilation and the new 13700 #pragma GCC visibility preprocessor command allows the setting of 13701 default ELF visibility for a region of code. Using 13702 -fvisibility=hidden especially in combination with the new 13703 -fvisibility-inlines-hidden can yield substantial improvements in 13704 output binary quality including avoiding PLT indirection overheads, 13705 reduction of the exported symbol count by up to 60% (with resultant 13706 improvements to link and load times), better scope for the 13707 optimizer to improve code and up to a 20% reduction in binary size. 13708 Using these options correctly yields a binary with a similar symbol 13709 count to a Windows DLL. 13710 Perhaps more importantly, this new feature finally allows (with 13711 careful planning) complete avoidance of symbol clashes when 13712 manually loading shared objects with RTLD_GLOBAL, thus finally 13713 solving problems many projects such as python were forced to use 13714 RTLD_LOCAL for (with its resulting issues for C++ correctness). You 13715 can find more information about using these options at 13716 [11]https://gcc.gnu.org/wiki/Visibility. 13717 __________________________________________________________________ 13718 13719 GCC 4.0.1 13720 13721 This is the [12]list of problem reports (PRs) from GCC's bug tracking 13722 system that are known to be fixed in the 4.0.1 release. This list might 13723 not be complete (that is, it is possible that some PRs that have been 13724 fixed are not listed here). 13725 13726 GCC 4.0.2 13727 13728 This is the [13]list of problem reports (PRs) from GCC's bug tracking 13729 system that are known to be fixed in the 4.0.2 release. This list might 13730 not be complete (that is, it is possible that some PRs that have been 13731 fixed are not listed here). 13732 13733 Unfortunately, due to a release engineering failure, this release has a 13734 regression on Solaris that will affect some C++ programs. We suggest 13735 that Solaris users apply a [14]patch that corrects the problem. Users 13736 who do not wish to apply the patch should explicitly link C++ programs 13737 with the -pthreads option, even if they do not use threads. This 13738 problem has been corrected in the current 4.0 branch sources and will 13739 not be present in GCC 4.0.3. 13740 13741 GCC 4.0.3 13742 13743 Starting with this release, the function getcontext is recognized by 13744 the compiler as having the same semantics as the setjmp function. In 13745 particular, the compiler will ensure that all registers are dead before 13746 calling such a function and will emit a warning about the variables 13747 that may be clobbered after the second return from the function. 13748 13749 GCC 4.0.4 13750 13751 This is the [15]list of problem reports (PRs) from GCC's bug tracking 13752 system that are known to be fixed in the 4.0.4 release. This list might 13753 not be complete (that is, it is possible that some PRs that have been 13754 fixed are not listed here). 13755 13756 The 4.0.4 release is provided for those that require a high degree of 13757 binary compatibility with previous 4.0.x releases. For most users, the 13758 GCC team recommends that version 4.1.1 or later be used instead." 13759 13760 13761 For questions related to the use of GCC, please consult these web 13762 pages and the [16]GCC manuals. If that fails, the 13763 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13764 web pages and the development of GCC are welcome on our developer 13765 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 13766 archives. 13767 13768 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 13769 distribution of this entire article is permitted in any medium, 13770 provided this notice is preserved. 13771 13772 These pages are [21]maintained by the GCC team. Last modified 13773 2021-07-28[22]. 13774 13775 References 13776 13777 1. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 13778 2. https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html 13779 3. http://gcc.gnu.org/projects/tree-ssa/ 13780 4. http://gcc.gnu.org/projects/tree-ssa/vectorization.html 13781 5. http://gcc.gnu.org/news/sms.html 13782 6. https://www.akkadia.org/drepper/dsohowto.pdf 13783 7. http://gcc.gnu.org/gcc-4.0/changes.html#visibility 13784 8. https://itanium-cxx-abi.github.io/cxx-abi/ 13785 9. http://gcc.gnu.org/fortran/ 13786 10. https://gcc.gnu.org/install/ 13787 11. https://gcc.gnu.org/wiki/Visibility 13788 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.1 13789 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.2 13790 14. https://gcc.gnu.org/ml/gcc-cvs/2005-09/msg00984.html 13791 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.4 13792 16. https://gcc.gnu.org/onlinedocs/ 13793 17. mailto:gcc-help (a] gcc.gnu.org 13794 18. mailto:gcc (a] gcc.gnu.org 13795 19. https://gcc.gnu.org/lists.html 13796 20. https://www.fsf.org/ 13797 21. https://gcc.gnu.org/about.html 13798 22. http://validator.w3.org/check/referer 13799 ====================================================================== 13800 http://gcc.gnu.org/gcc-3.4/index.html 13801 GCC 3.4 Release Series 13802 13803 (This release series is no longer supported.) 13804 13805 May 26, 2006 13806 13807 The [1]GNU project and the GCC developers are pleased to announce the 13808 release of GCC 3.4.6. 13809 13810 This release is a bug-fix release, containing fixes for regressions in 13811 GCC 3.4.4 relative to previous releases of GCC. This is the last of the 13812 3.4.x series. 13813 13814 The GCC 3.4 release series includes numerous [2]new features, 13815 improvements, bug fixes, and other changes, thanks to an [3]amazing 13816 group of volunteers. 13817 13818 Release History 13819 13820 GCC 3.4.6 13821 March 6, 2006 ([4]changes) 13822 13823 GCC 3.4.5 13824 November 30, 2005 ([5]changes) 13825 13826 GCC 3.4.4 13827 May 18, 2005 ([6]changes) 13828 13829 GCC 3.4.3 13830 November 4, 2004 ([7]changes) 13831 13832 GCC 3.4.2 13833 September 6, 2004 ([8]changes) 13834 13835 GCC 3.4.1 13836 July 1, 2004 ([9]changes) 13837 13838 GCC 3.4.0 13839 April 18, 2004 ([10]changes) 13840 13841 References and Acknowledgements 13842 13843 GCC used to stand for the GNU C Compiler, but since the compiler 13844 supports several other languages aside from C, it now stands for the 13845 GNU Compiler Collection. 13846 13847 A list of [11]successful builds is updated as new information becomes 13848 available. 13849 13850 The GCC developers would like to thank the numerous people that have 13851 contributed new features, improvements, bug fixes, and other changes as 13852 well as test results to GCC. This [12]amazing group of volunteers is 13853 what makes GCC successful. 13854 13855 For additional information about GCC please refer to the [13]GCC 13856 project web site or contact the [14]GCC development mailing list. 13857 13858 To obtain GCC please use [15]our mirror sites, or [16]our version 13859 control system. 13860 13861 13862 For questions related to the use of GCC, please consult these web 13863 pages and the [17]GCC manuals. If that fails, the 13864 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13865 web pages and the development of GCC are welcome on our developer 13866 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 13867 archives. 13868 13869 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 13870 distribution of this entire article is permitted in any medium, 13871 provided this notice is preserved. 13872 13873 These pages are [22]maintained by the GCC team. Last modified 13874 2021-07-28[23]. 13875 13876 References 13877 13878 1. http://www.gnu.org/ 13879 2. http://gcc.gnu.org/gcc-3.4/changes.html 13880 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13881 4. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6 13882 5. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.5 13883 6. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.4 13884 7. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.3 13885 8. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.2 13886 9. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.1 13887 10. http://gcc.gnu.org/gcc-3.4/changes.html 13888 11. http://gcc.gnu.org/gcc-3.4/buildstat.html 13889 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13890 13. http://gcc.gnu.org/index.html 13891 14. mailto:gcc (a] gcc.gnu.org 13892 15. http://gcc.gnu.org/mirrors.html 13893 16. http://gcc.gnu.org/git.html 13894 17. https://gcc.gnu.org/onlinedocs/ 13895 18. mailto:gcc-help (a] gcc.gnu.org 13896 19. mailto:gcc (a] gcc.gnu.org 13897 20. https://gcc.gnu.org/lists.html 13898 21. https://www.fsf.org/ 13899 22. https://gcc.gnu.org/about.html 13900 23. http://validator.w3.org/check/referer 13901 ====================================================================== 13902 http://gcc.gnu.org/gcc-3.4/changes.html 13903 GCC 3.4 Release Series 13904 Changes, New Features, and Fixes 13905 13906 The final release in the 3.4 release series is [1]GCC 3.4.6. The series 13907 is now closed. 13908 13909 GCC 3.4 has [2]many improvements in the C++ front end. Before reporting 13910 a bug, please make sure it's really GCC, and not your code, that is 13911 broken. 13912 13913 Caveats 13914 13915 * GNU Make is now required to build GCC. 13916 * With -nostdinc the preprocessor used to ignore both standard 13917 include paths and include paths contained in environment variables. 13918 It was neither documented nor intended that environment variable 13919 paths be ignored, so this has been corrected. 13920 * GCC no longer accepts the options -fvolatile, -fvolatile-global and 13921 -fvolatile-static. It is unlikely that they worked correctly in any 13922 3.x release. 13923 * GCC no longer ships <varargs.h>. Use <stdarg.h> instead. 13924 * Support for all the systems [3]obsoleted in GCC 3.3 has been 13925 removed from GCC 3.4. See below for a [4]list of systems which are 13926 obsoleted in this release. 13927 * GCC now requires an ISO C90 (ANSI C89) C compiler to build. K&R C 13928 compilers will not work. 13929 * The implementation of the [5]MIPS ABIs has changed. As a result, 13930 the code generated for certain MIPS targets will not be binary 13931 compatible with earlier releases. 13932 * In previous releases, the MIPS port had a fake "hilo" register with 13933 the user-visible name accum. This register has been removed. 13934 * The implementation of the [6]SPARC ABIs has changed. As a result, 13935 the code generated will not be binary compatible with earlier 13936 releases in certain cases. 13937 * The configure option --enable-threads=pthreads has been removed; 13938 use --enable-threads=posix instead, which should have the same 13939 effect. 13940 * Code size estimates used by inlining heuristics for C, Objective-C, 13941 C++ and Java have been redesigned significantly. As a result the 13942 parameters of -finline-insns, --param max-inline-insns-single and 13943 --param max-inline-insns-auto need to be reconsidered. 13944 * --param max-inline-slope and --param min-inline-insns have been 13945 removed; they are not needed for the new bottom-up inlining 13946 heuristics. 13947 * The new unit-at-a-time compilation scheme has several compatibility 13948 issues: 13949 + The order in which functions, variables, and top-level asm 13950 statements are emitted may have changed. Code relying on some 13951 particular ordering needs to be updated. The majority of such 13952 top-level asm statements can be replaced by section 13953 attributes. 13954 + Unreferenced static variables and functions are removed. This 13955 may result in undefined references when an asm statement 13956 refers to the variable/function directly. In that case either 13957 the variable/function shall be listed in asm statement operand 13958 or in the case of top-level asm statements the attribute used 13959 shall be used to force function/variable to be always output 13960 and considered as a possibly used by unknown code. 13961 For variables the attribute is accepted only by GCC 3.4 and 13962 newer, while for earlier versions it is sufficient to use 13963 unused to silence warnings about the variables not being 13964 referenced. To keep code portable across different GCC 13965 versions, you can use appropriate preprocessor conditionals. 13966 + Static functions now can use non-standard passing conventions 13967 that may break asm statements calling functions directly. 13968 Again the attribute used shall be used to prevent this 13969 behavior. 13970 As a temporary workaround, -fno-unit-at-a-time can be used, but 13971 this scheme may not be supported by future releases of GCC. 13972 * GCC 3.4 automatically places zero-initialized variables in the .bss 13973 section on some operating systems. Versions of GNU Emacs up to (and 13974 including) 21.3 will not work correctly when using this 13975 optimization; you can use -fno-zero-initialized-in-bss to disable 13976 it. 13977 * If GCC 3.4 is configured with --enable-threads=posix (the default 13978 on most targets that support pthreads) then _REENTRANT will be 13979 defined unconditionally by some libstdc++ headers. C++ code which 13980 relies on that macro to detect whether multi-threaded code is being 13981 compiled might change in meaning, possibly resulting in linker 13982 errors for single-threaded programs. Affected users of [7]Boost 13983 should compile single-threaded code with -DBOOST_DISABLE_THREADS. 13984 See Bugzilla for [8]more information. 13985 13986 General Optimizer Improvements 13987 13988 * Usability of the profile feedback and coverage testing has been 13989 improved. 13990 + Performance of profiled programs has been improved by faster 13991 profile merging code. 13992 + Better use of the profile feedback for optimization (loop 13993 unrolling and loop peeling). 13994 + File locking support allowing fork() calls and parallel runs 13995 of profiled programs. 13996 + Coverage file format has been redesigned. 13997 + gcov coverage tool has been improved. 13998 + make profiledbootstrap available to build a faster compiler. 13999 Experiments made on i386 hardware showed an 11% speedup on -O0 14000 and a 7.5% speedup on -O2 compilation of a [9]large C++ 14001 testcase. 14002 + New value profiling pass enabled via -fprofile-values 14003 + New value profile transformations pass enabled via -fvpt aims 14004 to optimize some code sequences by exploiting knowledge about 14005 value ranges or other properties of the operands. At the 14006 moment a conversion of expensive divisions into cheaper 14007 operations has been implemented. 14008 + New -fprofile-generate and -fprofile-use command-line options 14009 to simplify the use of profile feedback. 14010 * A new unit-at-a-time compilation scheme for C, Objective-C, C++ and 14011 Java which is enabled via -funit-at-a-time (and implied by -O2). In 14012 this scheme a whole file is parsed first and optimized later. The 14013 following basic inter-procedural optimizations are implemented: 14014 + Removal of unreachable functions and variables 14015 + Discovery of local functions (functions with static linkage 14016 whose address is never taken) 14017 + On i386, these local functions use register parameter passing 14018 conventions. 14019 + Reordering of functions in topological order of the call graph 14020 to enable better propagation of optimizing hints (such as the 14021 stack alignments needed by functions) in the back end. 14022 + Call graph based out-of-order inlining heuristics which allows 14023 to limit overall compilation unit growth (--param 14024 inline-unit-growth). 14025 Overall, the unit-at-a-time scheme produces a 1.3% improvement for 14026 the SPECint2000 benchmark on the i386 architecture (AMD Athlon 14027 CPU). 14028 * More realistic code size estimates used by inlining for C, 14029 Objective-C, C++ and Java. The growth of large functions can now be 14030 limited via --param large-function-insns and --param 14031 large-function-growth. 14032 * A new cfg-level loop optimizer pass replaces the old loop unrolling 14033 pass and adds two other loop transformations -- loop peeling and 14034 loop unswitching -- and also uses the profile feedback to limit 14035 code growth. (The three optimizations are enabled by 14036 -funroll-loops, -fpeel-loops and -funswitch-loops flags, 14037 respectively). 14038 The old loop unroller still can be enabled by -fold-unroll-loops 14039 and may produce better code in some cases, especially when the 14040 webizer optimization pass is not run. 14041 * A new web construction pass enabled via -fweb (and implied by -O3) 14042 improves the quality of register allocation, CSE, first scheduling 14043 pass and some other optimization passes by avoiding re-use of 14044 pseudo registers with non-overlapping live ranges. The pass almost 14045 always improves code quality but does make debugging difficult and 14046 thus is not enabled by default by -O2 14047 The pass is especially effective as cleanup after code duplication 14048 passes, such as the loop unroller or the tracer. 14049 * Experimental implementations of superblock or trace scheduling in 14050 the second scheduling pass can be enabled via 14051 -fsched2-use-superblocks and -fsched2-use-traces, respectively. 14052 14053 New Languages and Language specific improvements 14054 14055 Ada 14056 14057 * The Ada front end has been updated to include numerous bug fixes 14058 and enhancements. These include: 14059 + Improved project file support 14060 + Additional set of warnings about potential wrong code 14061 + Improved error messages 14062 + Improved code generation 14063 + Improved cross reference information 14064 + Improved inlining 14065 + Better run-time check elimination 14066 + Better error recovery 14067 + More efficient implementation of unbounded strings 14068 + Added features in GNAT.Sockets, GNAT.OS_Lib, GNAT.Debug_Pools, 14069 ... 14070 + New GNAT.xxxx packages (e.g. GNAT.Strings, 14071 GNAT.Exception_Action) 14072 + New pragmas 14073 + New -gnatS switch replacing gnatpsta 14074 + Implementation of new Ada features (in particular limited 14075 with, limited aggregates) 14076 14077 C/Objective-C/C++ 14078 14079 * Precompiled headers are now supported. Precompiled headers can 14080 dramatically speed up compilation of some projects. There are some 14081 known defects in the current precompiled header implementation that 14082 will result in compiler crashes in relatively rare situations. 14083 Therefore, precompiled headers should be considered a "technology 14084 preview" in this release. Read the manual for details about how to 14085 use precompiled headers. 14086 * File handling in the preprocessor has been rewritten. GCC no longer 14087 gets confused by symlinks and hardlinks, and now has a correct 14088 implementation of #import and #pragma once. These two directives 14089 have therefore been un-deprecated. 14090 * The undocumented extension that allowed C programs to have a label 14091 at the end of a compound statement, which has been deprecated since 14092 GCC 3.0, has been removed. 14093 * The cast-as-lvalue extension has been removed for C++ and 14094 deprecated for C and Objective-C. In particular, code like this: 14095 int i; 14096 (char) i = 5; 14097 14098 or this: 14099 char *p; 14100 ((int *) p)++; 14101 14102 is no longer accepted for C++ and will not be accepted for C and 14103 Objective-C in a future version. 14104 * The conditional-expression-as-lvalue extension has been deprecated 14105 for C and Objective-C. In particular, code like this: 14106 int a, b, c; 14107 (a ? b : c) = 2; 14108 14109 will not be accepted for C and Objective-C in a future version. 14110 * The compound-expression-as-lvalue extension has been deprecated for 14111 C and Objective-C. In particular, code like this: 14112 int a, b; 14113 (a, b) = 2; 14114 14115 will not be accepted for C and Objective-C in a future version. A 14116 possible non-intrusive workaround is the following: 14117 (*(a, &b)) = 2; 14118 14119 * Several [10]built-in functions such as __builtin_popcount for 14120 counting bits, finding the highest and lowest bit in a word, and 14121 parity have been added. 14122 * The -fwritable-strings option has been deprecated and will be 14123 removed. 14124 * Many C math library functions are now recognized as built-ins and 14125 optimized. 14126 * The C, C++, and Objective-C compilers can now handle source files 14127 written in any character encoding supported by the host C library. 14128 The default input character set is taken from the current locale, 14129 and may be overridden with the -finput-charset command line option. 14130 In the future we will add support for inline encoding markers. 14131 14132 C++ 14133 14134 * G++ is now much closer to full conformance to the ISO/ANSI C++ 14135 standard. This means, among other things, that a lot of invalid 14136 constructs which used to be accepted in previous versions will now 14137 be rejected. It is very likely that existing C++ code will need to 14138 be fixed. This document lists some of the most common issues. 14139 * A hand-written recursive-descent C++ parser has replaced the 14140 YACC-derived C++ parser from previous GCC releases. The new parser 14141 contains much improved infrastructure needed for better parsing of 14142 C++ source codes, handling of extensions, and clean separation 14143 (where possible) between proper semantics analysis and parsing. The 14144 new parser fixes many bugs that were found in the old parser. 14145 * You must now use the typename and template keywords to disambiguate 14146 dependent names, as required by the C++ standard. 14147 struct K { 14148 typedef int mytype_t; 14149 }; 14150 14151 template <class T1> struct A { 14152 template <class T2> struct B { 14153 void callme(void); 14154 }; 14155 14156 template <int N> void bar(void) 14157 { 14158 // Use 'typename' to tell the parser that T1::mytype_t names 14159 // a type. This is needed because the name is dependent (in 14160 // this case, on template parameter T1). 14161 typename T1::mytype_t x; 14162 x = 0; 14163 } 14164 }; 14165 14166 template <class T> void template_func(void) 14167 { 14168 // Use 'template' to prefix member templates within 14169 // dependent types (a has type A<T>, which depends on 14170 // the template parameter T). 14171 A<T> a; 14172 a.template bar<0>(); 14173 14174 // Use 'template' to tell the parser that B is a nested 14175 // template class (dependent on template parameter T), and 14176 // 'typename' because the whole A<T>::B<int> is 14177 // the name of a type (again, dependent). 14178 typename A<T>::template B<int> b; 14179 b.callme(); 14180 } 14181 14182 void non_template_func(void) 14183 { 14184 // Outside of any template class or function, no names can be 14185 // dependent, so the use of the keyword 'typename' and 'template' 14186 // is not needed (and actually forbidden). 14187 A<K> a; 14188 a.bar<0>(); 14189 A<K>::B<float> b; 14190 b.callme(); 14191 } 14192 * In a template definition, unqualified names will no longer find 14193 members of a dependent base (as specified by [temp.dep]/3 in the 14194 C++ standard). For example, 14195 template <typename T> struct B { 14196 int m; 14197 int n; 14198 int f (); 14199 int g (); 14200 }; 14201 int n; 14202 int g (); 14203 template <typename T> struct C : B<T> { 14204 void h () 14205 { 14206 m = 0; // error 14207 f (); // error 14208 n = 0; // ::n is modified 14209 g (); // ::g is called 14210 } 14211 }; 14212 You must make the names dependent, e.g. by prefixing them with 14213 this->. Here is the corrected definition of C<T>::h, 14214 template <typename T> void C<T>::h () 14215 { 14216 this->m = 0; 14217 this->f (); 14218 this->n = 0 14219 this->g (); 14220 } 14221 As an alternative solution (unfortunately not backwards compatible 14222 with GCC 3.3), you may use using declarations instead of this->: 14223 template <typename T> struct C : B<T> { 14224 using B<T>::m; 14225 using B<T>::f; 14226 using B<T>::n; 14227 using B<T>::g; 14228 void h () 14229 { 14230 m = 0; 14231 f (); 14232 n = 0; 14233 g (); 14234 } 14235 }; 14236 * In templates, all non-dependent names are now looked up and bound 14237 at definition time (while parsing the code), instead of later when 14238 the template is instantiated. For instance: 14239 void foo(int); 14240 14241 template <int> struct A { 14242 static void bar(void){ 14243 foo('a'); 14244 } 14245 }; 14246 14247 void foo(char); 14248 14249 int main() 14250 { 14251 A<0>::bar(); // Calls foo(int), used to call foo(char). 14252 } 14253 14254 * In an explicit instantiation of a class template, you must use 14255 class or struct before the template-id: 14256 template <int N> 14257 class A {}; 14258 14259 template A<0>; // error, not accepted anymore 14260 template class A<0>; // OK 14261 * The "named return value" and "implicit typename" extensions have 14262 been removed. 14263 * Default arguments in function types have been deprecated and will 14264 be removed. 14265 * ARM-style name-injection of friend declarations has been deprecated 14266 and will be removed. For example: struct S { friend void f(); }; 14267 void g() { f(); } will not be accepted by future versions of G++; 14268 instead a declaration of "f" will need to be present outside of the 14269 scope of "S". 14270 * Covariant returns are implemented for all but varadic functions 14271 that require an adjustment. 14272 * When -pedantic is used, G++ now issues errors about spurious 14273 semicolons. For example, 14274 namespace N {}; // Invalid semicolon. 14275 void f() {}; // Invalid semicolon. 14276 * G++ no longer accepts attributes for a declarator after the 14277 initializer associated with that declarator. For example, 14278 X x(1) __attribute__((...)); 14279 is no longer accepted. Instead, use: 14280 X x __attribute__((...)) (1); 14281 * Inside the scope of a template class, the name of the class itself 14282 can be treated as either a class or a template. So GCC used to 14283 accept the class name as argument of type template, and template 14284 template parameter. However this is not C++ standard compliant. Now 14285 the name is not treated as a valid template template argument 14286 unless you qualify the name by its scope. For example, the code 14287 below no longer compiles. 14288 template <template <class> class TT> class X {}; 14289 template <class T> class Y { 14290 X<Y> x; // Invalid, Y is always a type template parameter. 14291 }; 14292 The valid code for the above example is 14293 X< ::Y> x; // Valid. 14294 (Notice the space between < and : to prevent GCC to interpret this 14295 as a digraph for [.) 14296 * Friend declarations that refer to template specializations are 14297 rejected if the template has not already been declared. For 14298 example, 14299 template <typename T> 14300 class C { 14301 friend void f<> (C&); 14302 }; 14303 is rejected. You must first declare f as a template, 14304 template <typename T> 14305 void f(T); 14306 * In case of friend declarations, every name used in the friend 14307 declaration must be accessible at the point of that declaration. 14308 Previous versions of G++ used to be less strict about this and 14309 allowed friend declarations for private class members, for example. 14310 See the ISO C++ Standard Committee's [11]defect report #209 for 14311 details. 14312 * Declaration of member functions of class templates as friends are 14313 supported. For example, 14314 template <typename T> struct A { 14315 void f(); 14316 }; 14317 class C { 14318 template <typename T> friend void A<T>::f(); 14319 }; 14320 * You must use template <> to introduce template specializations, as 14321 required by the standard. For example, 14322 template <typename T> 14323 struct S; 14324 14325 struct S<int> { }; 14326 is rejected. You must write, 14327 template <> struct S<int> {}; 14328 * G++ used to accept code like this, 14329 struct S { 14330 int h(); 14331 void f(int i = g()); 14332 int g(int i = h()); 14333 }; 14334 This behavior is not mandated by the standard. Now G++ issues an 14335 error about this code. To avoid the error, you must move the 14336 declaration of g before the declaration of f. The default arguments 14337 for g must be visible at the point where it is called. 14338 * The C++ ABI Section 3.3.3 specifications for the array construction 14339 routines __cxa_vec_new2 and __cxa_vec_new3 were changed to return 14340 NULL when the allocator argument returns NULL. These changes are 14341 incorporated into the libstdc++ runtime library. 14342 * Using a name introduced by a typedef in a friend declaration or in 14343 an explicit instantiation is now rejected, as specified by the ISO 14344 C++ standard. 14345 class A; 14346 typedef A B; 14347 class C { 14348 friend class B; // error, no typedef name here 14349 friend B; // error, friend always needs class/struct/enum 14350 friend class A; // OK 14351 }; 14352 14353 template <int> class Q {}; 14354 typedef Q<0> R; 14355 template class R; // error, no typedef name here 14356 template class Q<0>; // OK 14357 * When allocating an array with a new expression, GCC used to allow 14358 parentheses around the type name. This is actually ill-formed and 14359 it is now rejected: 14360 int* a = new (int)[10]; // error, not accepted anymore 14361 int* a = new int[10]; // OK 14362 * When binding an rvalue of class type to a reference, the copy 14363 constructor of the class must be accessible. For instance, consider 14364 the following code: 14365 class A 14366 { 14367 public: 14368 A(); 14369 14370 private: 14371 A(const A&); // private copy ctor 14372 }; 14373 14374 A makeA(void); 14375 void foo(const A&); 14376 14377 void bar(void) 14378 { 14379 foo(A()); // error, copy ctor is not accessible 14380 foo(makeA()); // error, copy ctor is not accessible 14381 14382 A a1; 14383 foo(a1); // OK, a1 is a lvalue 14384 } 14385 This might be surprising at first sight, especially since most 14386 popular compilers do not correctly implement this rule ([12]further 14387 details). 14388 * When forming a pointer to member or a pointer to member function, 14389 access checks for class visibility (public, protected, private) are 14390 now performed using the qualifying scope of the name itself. This 14391 is better explained with an example: 14392 class A 14393 { 14394 public: 14395 void pub_func(); 14396 protected: 14397 void prot_func(); 14398 private: 14399 void priv_func(); 14400 }; 14401 14402 class B : public A 14403 { 14404 public: 14405 void foo() 14406 { 14407 &A::pub_func; // OK, pub_func is accessible through A 14408 &A::prot_func; // error, cannot access prot_func through A 14409 &A::priv_func; // error, cannot access priv_func through A 14410 14411 &B::pub_func; // OK, pub_func is accessible through B 14412 &B::prot_func; // OK, can access prot_func through B (within B) 14413 &B::priv_func; // error, cannot access priv_func through B 14414 } 14415 }; 14416 14417 Runtime Library (libstdc++) 14418 14419 * Optimization work: 14420 + Streamlined streambuf, filebuf, separate synched with C 14421 Standard I/O streambuf. 14422 + All formatted I/O now uses cached locale information. 14423 + STL optimizations (memory/speed for list, red-black trees as 14424 used by sets and maps). 14425 + More use of GCC builtins. 14426 + String optimizations (avoid contention on 14427 increment/decrement-and-test of the reference count in the 14428 empty-string object, constructor from input_iterators 14429 speedup). 14430 * Static linkage size reductions. 14431 * Large File Support (files larger than 2 GB on 32-bit systems). 14432 * Wide character and variable encoding filebuf work (UTF-8, Unicode). 14433 * Generic character traits. 14434 * Also support wchar_t specializations on Mac OS 10.3.x, FreeBSD 5.x, 14435 Solaris 2.7 and above, AIX 5.x, Irix 6.5. 14436 * The allocator class is now standard-conformant, and two additional 14437 extension allocators have been added, mt_alloc and 14438 bitmap_allocator. 14439 * PCH support: -include bits/stdc++.h (2x compile speedup). 14440 * Rewrote __cxa_demangle with support for C++ style allocators. 14441 * New debug modes for STL containers and iterators. 14442 * Testsuite rewrite: five times as many tests, plus increasingly 14443 sophisticated tests, including I/O, MT, multi-locale, wide and 14444 narrow characters. 14445 * Use current versions of GNU "autotools" for build/configuration. 14446 14447 Objective-C 14448 14449 * The Objective-C front end has been updated to include the numerous 14450 bug fixes and enhancements previously available only in Apple's 14451 version of GCC. These include: 14452 + Structured exception (@try... @catch... @finally, @throw) and 14453 synchronization (@synchronized) support. These are accessible 14454 via the -fobjc-exceptions switch; as of this writing, they may 14455 only be used in conjunction with -fnext-runtime on Mac OS X 14456 10.3 and later. See [13]Options Controlling Objective-C 14457 Dialect for more information. 14458 + An overhaul of @encode logic. The C99 _Bool and C++ bool type 14459 may now be encoded as 'B'. In addition, the back-end/codegen 14460 dependencies have been removed. 14461 + An overhaul of message dispatch construction, ensuring that 14462 the various receiver types (and casts thereof) are handled 14463 properly, and that correct diagnostics are issued. 14464 + Support for "Zero-Link" (-fzero-link) and "Fix-and-Continue" 14465 (-freplace-objc-classes) debugging modes, currently available 14466 on Mac OS X 10.3 and later. See [14]Options Controlling 14467 Objective-C Dialect for more information. 14468 + Access to optimized runtime entry points (-fno-nil-receivers ) 14469 on the assumption that message receivers are never nil. This 14470 is currently available on Mac OS X 10.3 and later. See 14471 [15]Options Controlling Objective-C Dialect for more 14472 information. 14473 14474 Java 14475 14476 * Compiling a .jar file will now cause non-.class entries to be 14477 automatically compiled as resources. 14478 * libgcj has been ported to Darwin. 14479 * Jeff Sturm has adapted Jan Hubicka's call graph optimization code 14480 to gcj. 14481 * libgcj has a new gcjlib URL type; this lets URLClassLoader load 14482 code from shared libraries. 14483 * libgcj has been much more completely merged with [16]GNU Classpath. 14484 * Class loading is now much more correct; in particular the caller's 14485 class loader is now used when that is required. 14486 * [17]Eclipse 2.x will run out of the box using gij. 14487 * Parts of java.nio have been implemented. Direct and indirect 14488 buffers work, as do fundamental file and socket operations. 14489 * java.awt has been improved, though it is still not ready for 14490 general use. 14491 * The HTTP protocol handler now uses HTTP/1.1 and can handle the POST 14492 method. 14493 * The MinGW port has matured. Enhancements include socket timeout 14494 support, thread interruption, improved Runtime.exec() handling and 14495 support for accented characters in filenames. 14496 14497 Fortran 14498 14499 * Fortran improvements are listed in the [18]Fortran documentation. 14500 14501 New Targets and Target Specific Improvements 14502 14503 Alpha 14504 14505 * Several [19]built-in functions have been added such as 14506 __builtin_alpha_zap to allow utilizing the more obscure 14507 instructions of the CPU. 14508 * Parameter passing of complex arguments has changed to match the 14509 ABI. This change is incompatible with previous GCC versions, but 14510 does fix compatibility with the Tru64 compiler and several corner 14511 cases where GCC was incompatible with itself. 14512 14513 ARM 14514 14515 * Nicolas Pitre has contributed his hand-coded floating-point support 14516 code for ARM. It is both significantly smaller and faster than the 14517 existing C-based implementation, even when building applications 14518 for Thumb. The arm-elf configuration has been converted to use the 14519 new code. 14520 * Support for the Intel's iWMMXt architecture, a second generation 14521 XScale processor, has been added. Enabled at run time with the 14522 -mcpu=iwmmxt command line switch. 14523 * A new ARM target has been added: arm-wince-pe. This is similar to 14524 the arm-pe target, but it defaults to using the APCS32 ABI. 14525 * The existing ARM pipeline description has been converted to the use 14526 the [20]DFA processor pipeline model. There is not much change in 14527 code performance, but the description is now [21]easier to 14528 understand. 14529 * Support for the Cirrus EP9312 Maverick floating point co-processor 14530 added. Enabled at run time with the -mcpu=ep9312 command line 14531 switch. Note however that the multilibs to support this chip are 14532 currently disabled in gcc/config/arm/t-arm-elf, so if you want to 14533 enable their production you will have to uncomment the entries in 14534 that file. 14535 14536 H8/300 14537 14538 * Support for long long has been added. 14539 * Support for saveall attribute has been added. 14540 * Pavel Pisa contributed hand-written 32-bit-by-32-bit division code 14541 for H8/300H and H8S, which is much faster than the previous 14542 implementation. 14543 * A lot of small performance improvements. 14544 14545 IA-32/AMD64 (x86-64) 14546 14547 * Tuning for K8 (AMD Opteron/Athlon64) core is available via 14548 -march=k8 and -mcpu=k8. 14549 * Scalar SSE code generation carefully avoids reformatting penalties, 14550 hidden dependencies and minimizes the number of uops generated on 14551 both Intel and AMD CPUs. 14552 * Vector MMX and SSE operands are now passed in registers to improve 14553 performance and match the argument passing convention used by the 14554 Intel C++ Compiler. As a result it is not possible to call 14555 functions accepting vector arguments compiled by older GCC version. 14556 * Conditional jump elimination is now more aggressive on modern CPUs. 14557 * The Athlon ports has been converted to use the DFA processor 14558 pipeline description. 14559 * Optimization of indirect tail calls is now possible in a similar 14560 fashion as direct sibcall optimization. 14561 * Further small performance improvements. 14562 * -m128bit-long-double is now less buggy. 14563 * __float128 support in 64-bit compilation. 14564 * Support for data structures exceeding 2GB in 64-bit mode. 14565 * -mcpu has been renamed to -mtune. 14566 14567 IA-64 14568 14569 * Tuning code for the Itanium 2 processor has been added. The 14570 generation of code tuned for Itanium 2 (option -mtune=itanium2) is 14571 enabled by default now. To generate code tuned for Itanium 1 the 14572 option -mtune=itanium1 should be used. 14573 * [22]DFA processor pipeline descriptions for the IA-64 processors 14574 have been added. This resulted in about 3% improvement on the 14575 SPECInt2000 benchmark for Itanium 2. 14576 * Instruction bundling for the IA-64 processors has been rewritten 14577 using the DFA pipeline hazard recognizer. It resulted in about 60% 14578 compiler speedup on the SPECInt2000 C programs. 14579 14580 M32R 14581 14582 * Support for the M32R/2 processor has been added by Renesas. 14583 * Support for an M32R GNU/Linux target and PIC code generation has 14584 been added by Renesas. 14585 14586 M68000 14587 14588 * Bernardo Innocenti (Develer S.r.l.) has contributed the 14589 m68k-uclinux target, based on former work done by Paul Dale 14590 (SnapGear Inc.). Code generation for the ColdFire processors family 14591 has been enhanced and extended to support the MCF 53xx and MCF 54xx 14592 cores, integrating former work done by Peter Barada (Motorola). 14593 14594 MIPS 14595 14596 Processor-specific changes 14597 14598 * Support for the RM7000 and RM9000 processors has been added. It can 14599 be selected using the -march compiler option and should work with 14600 any MIPS I (mips-*) or MIPS III (mips64-*) configuration. 14601 * Support for revision 2 of the MIPS32 ISA has been added. It can be 14602 selected with the command-line option -march=mips32r2. 14603 * There is a new option, -mfix-sb1, to work around certain SB-1 14604 errata. 14605 14606 Configuration 14607 14608 * It is possible to customize GCC using the following configure-time 14609 options: 14610 + --with-arch, which specifies the default value of the -march 14611 option. 14612 + --with-tune, which specifies the default value of the -mtune 14613 option. 14614 + --with-abi, which specifies the default ABI. 14615 + --with-float=soft, which tells GCC to use software floating 14616 point by default. 14617 + --with-float=hard, which tells GCC to use hardware floating 14618 point by default. 14619 * A 64-bit GNU/Linux port has been added. The associated 14620 configurations are mips64-linux-gnu and mips64el-linux-gnu. 14621 * The 32-bit GNU/Linux port now supports Java. 14622 * The IRIX 6 configuration now supports the o32 ABI and will build 14623 o32 multilibs by default. This support is compatible with both 14624 binutils and the SGI tools, but note that several features, 14625 including debugging information and DWARF2 exception handling, are 14626 only available when using the GNU assembler. Use of the GNU 14627 assembler and linker (version 2.15 or above) is strongly 14628 recommended. 14629 * The IRIX 6 configuration now supports 128-bit long doubles. 14630 * There are two new RTEMS-specific configurations, mips-rtems and 14631 mipsel-rtems. 14632 * There are two new *-elf configurations, mipsisa32r2-elf and 14633 mipsisa32r2el-elf. 14634 14635 General 14636 14637 * Several [23]ABI bugs have been fixed. Unfortunately, these changes 14638 will break binary compatibility with earlier releases. 14639 * GCC can now use explicit relocation operators when generating 14640 -mabicalls code. This behavior is controlled by -mexplicit-relocs 14641 and can have several performance benefits. For example: 14642 + It allows for more optimization of GOT accesses, including 14643 better scheduling and redundancy elimination. 14644 + It allows sibling calls to be implemented as jumps. 14645 + n32 and n64 leaf functions can use a call-clobbered global 14646 pointer instead of $28. 14647 + The code to set up $gp can be removed from functions that 14648 don't need it. 14649 * A new option, -mxgot, allows the GOT to be bigger than 64k. This 14650 option is equivalent to the assembler's -xgot option and should be 14651 used instead of -Wa,-xgot. 14652 * Frame pointer elimination is now supported when generating 64-bit 14653 MIPS16 code. 14654 * Inline block moves have been optimized to take more account of 14655 alignment information. 14656 * Many internal changes have been made to the MIPS port, mostly aimed 14657 at reducing the reliance on assembler macros. 14658 14659 PowerPC 14660 14661 * GCC 3.4 releases have a number of fixes for PowerPC and PowerPC64 14662 [24]ABI incompatibilities regarding the way parameters are passed 14663 during functions calls. These changes may result in incompatibility 14664 between code compiled with GCC 3.3 and GCC 3.4. 14665 14666 PowerPC Darwin 14667 14668 * Support for shared/dylib gcc libraries has been added. It is 14669 enabled by default on powerpc-apple-darwin7.0.0 and up. 14670 * Libgcj is enabled by default. On systems older than 14671 powerpc-apple-darwin7.0.0 you need to install dlcompat. 14672 * 128-bit IBM extended precision format support added for long 14673 double. 14674 14675 PowerPC64 GNU/Linux 14676 14677 * By default, PowerPC64 GNU/Linux now uses natural alignment of 14678 structure elements. The old four byte alignment for double, with 14679 special rules for a struct starting with a double, can be chosen 14680 with -malign-power. This change may result in incompatibility 14681 between code compiled with GCC 3.3 and GCC 3.4. 14682 * -mabi=altivec is now the default rather than -mabi=no-altivec. 14683 * 128-bit IBM extended precision format support added for long 14684 double. 14685 14686 S/390 and zSeries 14687 14688 * New command-line options allow to specify the intended execution 14689 environment for generated code: 14690 + -mesa/-mzarch allows to specify whether to generate code 14691 running in ESA/390 mode or in z/Architecture mode (this is 14692 applicable to 31-bit code only). 14693 + -march allows to specify a minimum processor architecture 14694 level (g5, g6, z900, or z990). 14695 + -mtune allows to specify which processor to tune for. 14696 * It is possible to customize GCC using the following configure-time 14697 options: 14698 + --with-mode, which specifies whether to default to assuming 14699 ESA/390 or z/Architecture mode. 14700 + --with-arch, which specifies the default value of the -march 14701 option. 14702 + --with-tune, which specifies the default value of the -mtune 14703 option. 14704 * Support for the z990 processor has been added, and can be selected 14705 using -march=z990 or -mtune=z990. This includes instruction 14706 scheduling tuned for the superscalar instruction pipeline of the 14707 z990 processor as well as support for all new instructions provided 14708 by the long-displacement facility. 14709 * Support to generate 31-bit code optimized for zSeries processors 14710 (running in ESA/390 or in z/Architecture mode) has been added. This 14711 can be selected using -march=z900 and -mzarch respectively. 14712 * Instruction scheduling for the z900 and z990 processors now uses 14713 the DFA pipeline hazard recognizer. 14714 * GCC no longer generates code to maintain a stack backchain, 14715 previously used to generate stack backtraces for debugging 14716 purposes. As replacement that does not incur runtime overhead, 14717 DWARF-2 call frame information is provided by GCC; this is 14718 supported by GDB 6.1. The old behavior can be restored using the 14719 -mbackchain option. 14720 * The stack frame size of functions may now exceed 2 GB in 64-bit 14721 code. 14722 * A port for the 64-bit IBM TPF operating system has been added; the 14723 configuration is s390x-ibm-tpf. This configuration is supported as 14724 cross-compilation target only. 14725 * Various changes to improve the generated code have been 14726 implemented, including: 14727 + GCC now uses the MULTIPLY AND ADD and MULTIPLY AND SUBTRACT 14728 instructions to significantly speed up many floating-point 14729 applications. 14730 + GCC now uses the ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL 14731 WITH BORROW instructions to speed up long long arithmetic. 14732 + GCC now uses the SEARCH STRING instruction to implement 14733 strlen(). 14734 + In many cases, function call overhead for 31-bit code has been 14735 reduced by placing the literal pool after the function code 14736 instead of after the function prolog. 14737 + Register 14 is no longer reserved in 64-bit code. 14738 + Handling of global register variables has been improved. 14739 14740 SPARC 14741 14742 * The option -mflat is deprecated. 14743 * Support for large (> 2GB) frames has been added to the 64-bit port. 14744 * Several [25]ABI bugs have been fixed. Unfortunately, these changes 14745 will break binary compatibility with earlier releases. 14746 * The default debugging format has been switched from STABS to 14747 DWARF-2 for 32-bit code on Solaris 7 and later. DWARF-2 is already 14748 the default debugging format for 64-bit code on Solaris. 14749 14750 SuperH 14751 14752 * Support for the SH2E processor has been added. Enabled at run time 14753 with the -m2e command line switch, or at configure time by 14754 specifying sh2e as the machine part of the target triple. 14755 14756 V850 14757 14758 * Support for the Mitsubishi V850E1 processor has been added. This is 14759 a variant of the V850E processor with some additional debugging 14760 instructions. 14761 14762 Xtensa 14763 14764 * Several ABI bugs have been fixed. Unfortunately, these changes 14765 break binary compatibility with earlier releases. 14766 + For big-endian processors, the padding of aggregate return 14767 values larger than a word has changed. If the size of an 14768 aggregate return value is not a multiple of 32 bits, previous 14769 versions of GCC inserted padding in the most-significant bytes 14770 of the first return value register. Aggregates larger than a 14771 word are now padded in the least-significant bytes of the last 14772 return value register used. Aggregates smaller than a word are 14773 still padded in the most-significant bytes. The return value 14774 padding has not changed for little-endian processors. 14775 + Function arguments with 16-byte alignment are now properly 14776 aligned. 14777 + The implementation of the va_list type has changed. A va_list 14778 value created by va_start from a previous release cannot be 14779 used with va_arg from this release, or vice versa. 14780 * More processor configuration options for Xtensa processors are 14781 supported: 14782 + the ABS instruction is now optional; 14783 + the ADDX* and SUBX* instructions are now optional; 14784 + an experimental CONST16 instruction can be used to synthesize 14785 constants instead of loading them from constant pools. 14786 These and other Xtensa processor configuration options can no 14787 longer be enabled or disabled by command-line options; the 14788 processor configuration must be specified by the xtensa-config.h 14789 header file when building GCC. Additionally, the 14790 -mno-serialize-volatile option is no longer supported. 14791 14792 Obsolete Systems 14793 14794 Support for a number of older systems has been declared obsolete in GCC 14795 3.4. Unless there is activity to revive them, the next release of GCC 14796 will have their sources permanently removed. 14797 14798 All configurations of the following processor architectures have been 14799 declared obsolete: 14800 * Mitsubishi D30V, d30v-* 14801 * AT&T DSP1600 and DSP1610, dsp16xx-* 14802 * Intel 80960, i960 14803 14804 Also, some individual systems have been obsoleted: 14805 * ARM Family 14806 + Support for generating code for operation in APCS/26 mode 14807 (-mapcs-26). 14808 * IBM ESA/390 14809 + "Bigfoot" port, i370-*. (The other port, s390-*, is actively 14810 maintained and supported.) 14811 * Intel 386 family 14812 + MOSS, i?86-moss-msdos and i?86-*-moss* 14813 + NCR 3000 running System V r.4, i?86-ncr-sysv4* 14814 + FreeBSD with a.out object format, i?86-*-freebsd*aout* and 14815 i?86-*-freebsd2* 14816 + GNU/Linux with a.out object format, i?86-linux*aout* 14817 + GNU/Linux with libc5, a.k.a. glibc1, i?86-linux*libc1* 14818 + Interix versions before Interix 3, i?86-*-interix 14819 + Mach microkernel, i?86-mach* 14820 + SCO UnixWare with UDK, i?86-*-udk* 14821 + Generic System V releases 1, 2, and 3, i?86-*-sysv[123]* 14822 + VSTa microkernel, i386-*-vsta 14823 * Motorola M68000 family 14824 + HPUX, m68k-hp-hpux* and m68000-hp-hpux* 14825 + NetBSD with a.out object format (before NetBSD 1.4), 14826 m68k-*-*-netbsd* except m68k-*-*-netbsdelf* 14827 + Generic System V r.4, m68k-*-sysv4* 14828 * VAX 14829 + Generic VAX, vax-*-* (This is generic VAX only; we have not 14830 obsoleted any VAX triples for specific operating systems.) 14831 14832 Documentation improvements 14833 14834 Other significant improvements 14835 14836 * The build system has undergone several significant cleanups. 14837 Subdirectories will only be configured if they are being built, and 14838 all subdirectory configures are run from the make command. The top 14839 level has been autoconfiscated. 14840 * Building GCC no longer writes to its source directory. This should 14841 help those wishing to share a read-only source directory over NFS 14842 or build from a CD. The exceptions to this feature are if you 14843 configure with either --enable-maintainer-mode or 14844 --enable-generated-files-in-srcdir. 14845 * The -W warning option has been renamed to -Wextra, which is more 14846 easily understood. The older spelling will be retained for 14847 backwards compatibility. 14848 * Substantial improvements in compile time have been made, 14849 particularly for non-optimizing compilations. 14850 __________________________________________________________________ 14851 14852 GCC 3.4.0 14853 14854 Bug Fixes 14855 14856 A vast number of bugs have been fixed in 3.4.0, too many to publish a 14857 complete list here. [26]Follow this link to query the Bugzilla database 14858 for the list of over 900 bugs fixed in 3.4.0. This is the list of all 14859 bugs marked as resolved and fixed in 3.4.0 that are not flagged as 3.4 14860 regressions. 14861 __________________________________________________________________ 14862 14863 GCC 3.4.1 14864 14865 Bug Fixes 14866 14867 This section lists the problem reports (PRs) from GCC's bug tracking 14868 system that are known to be fixed in the 3.4.1 release. This list might 14869 not be complete (that is, it is possible that some PRs that have been 14870 fixed are not listed here). 14871 14872 Bootstrap failures 14873 14874 * [27]10129 Ada bootstrap fails on PPC-Darwin - invalid assembler 14875 emitted - PIC related 14876 * [28]14576 [ARM] ICE in libiberty when building gcc-3.4 for arm-elf 14877 * [29]14760 A bug in configure.in prevents using both 14878 --program-suffix and --program-prefix 14879 * [30]14671 [hppa64] bootstrap fails: ICE in 14880 save_call_clobbered_regs, in caller_save.c 14881 * [31]15093 [alpha][Java] make bootstrap fails to configure libffi on 14882 Alpha 14883 * [32]15178 Solaris 9/x86 fails linking after stage 3 14884 14885 Multi-platform internal compiler errors (ICEs) 14886 14887 * [33]12753 (preprocessor) Memory corruption in preprocessor on bad 14888 input 14889 * [34]13985 ICE in gcc.c-torture/compile/930621-1.c 14890 * [35]14810 (c++) tree check failures with invalid code involving 14891 templates 14892 * [36]14883 (c++) ICE on invalid code, in cp_parser_lookup_name, in 14893 cp/parser.c 14894 * [37]15044 (c++) ICE on syntax error, template header 14895 * [38]15057 (c++) Compiling of conditional value throw constructs 14896 cause a segmentation violation 14897 * [39]15064 (c++) typeid of template parameter gives ICE 14898 * [40]15142 (c++) ICE when passing a string where a char* is expected 14899 in a throw statement 14900 * [41]15159 ICE in rtl_verify_flow_info_1 14901 * [42]15165 (c++) ICE in instantiate_template 14902 * [43]15193 Unary minus using pointer to V4SF vector causes 14903 -fforce-mem to exhaust all memory 14904 * [44]15209 (c++) Runs out of memory with packed structs 14905 * [45]15227 (c++) Trouble with invalid function definition 14906 * [46]15285 (c++) instantiate_type ICE when forming pointer to 14907 template function 14908 * [47]15299 (c++) ICE in resolve_overloaded_unification 14909 * [48]15329 (c++) ICE on constructor of member template 14910 * [49]15550 ICE in extract_insn, in recog.c 14911 * [50]15554 (c++) ICE in tsubst_copy, in cp/pt.c 14912 * [51]15640 (c++) ICE on invalid code in arg_assoc, in 14913 cp/name-lookup.c 14914 * [52]15666 [unit-at-a-time] Gcc abort on valid code 14915 * [53]15696 (c++) ICE with bad pointer-to-member code 14916 * [54]15701 (c++) ICE with friends and template template parameter 14917 * [55]15761 ICE in do_SUBST, in combine.c 14918 * [56]15829 (c++) ICE on Botan-1.3.13 due to -funroll-loops 14919 14920 Ada 14921 14922 * [57]14538 All RTEMS targets broken for gnat 14923 14924 C front end 14925 14926 * [58]12391 missing warning about assigning to an incomplete type 14927 * [59]14649 atan(1.0) should not be a constant expression 14928 * [60]15004 [unit-at-a-time] no warning for unused paramater in 14929 static function 14930 * [61]15749 --pedantic-errors behaves differently from --pedantic 14931 with C-compiler on GNU/Linux 14932 14933 C++ compiler and library 14934 14935 * [62]10646 non-const reference is incorrectly matched in a "const T" 14936 partial specialization 14937 * [63]12077 wcin.rdbuf()->in_avail() return value too high 14938 * [64]13598 enc_filebuf doesn't work 14939 * [65]14211 const_cast returns lvalue but should be rvalue 14940 * [66]14220 num_put::do_put() undesired float/double behavior 14941 * [67]14245 problem with user-defined allocators in std::basic_string 14942 * [68]14340 libstdc++ Debug mode: failure to convert iterator to 14943 const_iterator 14944 * [69]14600 __gnu_cxx::stdio_sync_filebuf should expose internal 14945 FILE* 14946 * [70]14668 no warning anymore for reevaluation of declaration 14947 * [71]14775 LFS (large file support) tests missing 14948 * [72]14821 Duplicate namespace alias declaration should not conflict 14949 * [73]14930 Friend declaration ignored 14950 * [74]14932 cannot use offsetof to get offsets of array elements in 14951 g++ 3.4.0 14952 * [75]14950 [non unit-at-a-time] always_inline does not mix with 14953 templates and -O0 14954 * [76]14962 g++ ignores #pragma redefine_extname 14955 * [77]14975 Segfault on low-level write error during imbue 14956 * [78]15002 Linewise stream input is unusably slow (std::string slow) 14957 * [79]15025 compiler accepts redeclaration of template as 14958 non-template 14959 * [80]15046 [arm] Math functions misdetected by cross configuration 14960 * [81]15069 a bit test on a variable of enum type is miscompiled 14961 * [82]15074 g++ -lsupc++ still links against libstdc++ 14962 * [83]15083 spurious "statement has no effect" warning 14963 * [84]15096 parse error with templates and pointer to const member 14964 * [85]15287 combination of operator[] and operator .* fails in 14965 templates 14966 * [86]15317 __attribute__ unused in first parameter of constructor 14967 gives error 14968 * [87]15337 sizeof on incomplete type diagnostic 14969 * [88]15361 bitset<>::_Find_next fails 14970 * [89]15412 _GLIBCXX_ symbols symbols defined and used in different 14971 namespaces 14972 * [90]15427 valid code results in incomplete type error 14973 * [91]15471 Incorrect member pointer offsets in anonymous 14974 structs/unions 14975 * [92]15503 nested template problem 14976 * [93]15507 compiler hangs while laying out union 14977 * [94]15542 operator & and template definitions 14978 * [95]15565 SLES9: leading + sign for unsigned int with showpos 14979 * [96]15625 friend defined inside a template fails to find static 14980 function 14981 * [97]15629 Function templates, overloads, and friend name injection 14982 * [98]15742 'noreturn' attribute ignored in method of template 14983 functions. 14984 * [99]15775 Allocator::pointer consistently ignored 14985 * [100]15821 Duplicate namespace alias within namespace rejected 14986 * [101]15862 'enum yn' fails (confict with undeclared builtin) 14987 * [102]15875 rejects pointer to member in template 14988 * [103]15877 valid code using templates and anonymous enums is 14989 rejected 14990 * [104]15947 Puzzling error message for wrong destructor declaration 14991 in template class 14992 * [105]16020 cannot copy __gnu_debug::bitset 14993 * [106]16154 input iterator concept too restrictive 14994 * [107]16174 deducing top-level consts 14995 14996 Java 14997 14998 * [108]14315 Java compiler is not parallel make safe 14999 15000 Fortran 15001 15002 * [109]15151 [g77] incorrect logical i/o in 64-bit mode 15003 15004 Objective-C 15005 15006 * [110]7993 private variables cannot be shadowed in subclasses 15007 15008 Optimization bugs 15009 15010 * [111]15228 useless copies of floating point operands 15011 * [112]15345 [non-unit-at-a-time] unreferenced nested inline 15012 functions not optimized away 15013 * [113]15945 Incorrect floating point optimization 15014 * [114]15526 ftrapv aborts on 0 * (-1) 15015 * [115]14690 Miscompiled POOMA tests 15016 * [116]15112 GCC generates code to write to unchanging memory 15017 15018 Preprocessor 15019 15020 * [117]15067 Minor glitch in the source of cpp 15021 15022 Main driver program bugs 15023 15024 * [118]1963 collect2 interprets -oldstyle_liblookup as -o 15025 ldstyle_liblookup 15026 15027 x86-specific (Intel/AMD) 15028 15029 * [119]15717 Error: can't resolve `L0' {*ABS* section} - `xx' {*UND* 15030 section} 15031 15032 HPPA-specific 15033 15034 * [120]14782 GCC produces an unaligned data access at -O2 15035 * [121]14828 FAIL: gcc.c-torture/execute/20030408-1.c execution, -O2 15036 * [122]15202 ICE in reload_cse_simplify_operands, in postreload.c 15037 15038 IA64-specific 15039 15040 * [123]14610 __float80 constants incorrectly emitted 15041 * [124]14813 init_array sections are initialized in the wrong order 15042 * [125]14857 GCC segfault on duplicated asm statement 15043 * [126]15598 Gcc 3.4 ICE on valid code 15044 * [127]15653 Gcc 3.4 ICE on valid code 15045 15046 MIPS-specific 15047 15048 * [128]15189 wrong filling of delay slot with -march=mips1 -G0 15049 -mno-split-addresses -mno-explicit-relocs 15050 * [129]15331 Assembler error building gnatlib on IRIX 6.5 with GNU as 15051 2.14.91 15052 * [130]16144 Bogus reference to __divdf3 when -O1 15053 * [131]16176 Miscompilation of unaligned data in MIPS backend 15054 15055 PowerPC-specific 15056 15057 * [132]11591 ICE in gcc.dg/altivec-5.c 15058 * [133]12028 powerpc-eabispe produces bad sCOND operation 15059 * [134]14478 rs6000 geu/ltu patterns generate incorrect code 15060 * [135]14567 long double and va_arg complex args 15061 * [136]14715 Altivec stack layout may overlap gpr save with stack 15062 temps 15063 * [137]14902 (libstdc++) Stream checking functions fail when -pthread 15064 option is used. 15065 * [138]14924 Compiler ICE on valid code 15066 * [139]14960 -maltivec affects vector return with -mabi=no-altivec 15067 * [140]15106 vector varargs failure passing from altivec to 15068 non-altivec code for -m32 15069 * [141]16026 ICE in function.c:4804, assign_parms, when -mpowerpc64 & 15070 half-word operation 15071 * [142]15191 -maltivec -mabi=no-altivec results in mis-aligned lvx 15072 and stvx 15073 * [143]15662 Segmentation fault when an exception is thrown - even if 15074 try and catch are specified 15075 15076 s390-specific 15077 15078 * [144]15054 Bad code due to overlapping stack temporaries 15079 15080 SPARC-specific 15081 15082 * [145]15783 ICE with union assignment in 64-bit mode 15083 * [146]15626 GCC 3.4 emits "ld: warning: relocation error: 15084 R_SPARC_UA32" 15085 15086 x86-64-specific 15087 15088 * [147]14326 boehm-gc hardcodes to 3DNow! prefetch for x86_64 15089 * [148]14723 Backported -march=nocona from mainline 15090 * [149]15290 __float128 failed to pass to function properly 15091 15092 Cygwin/Mingw32-specific 15093 15094 * [150]15250 Option -mms-bitfields support on GCC 3.4 is not 15095 conformant to MS layout 15096 * [151]15551 -mtune=pentium4 -O2 with sjlj EH breaks stack probe 15097 worker on windows32 targets 15098 15099 Bugs specific to embedded processors 15100 15101 * [152]8309 [m68k] -m5200 produces erroneous SImode set of short 15102 varaible on stack 15103 * [153]13250 [SH] Gcc code for rotation clobbers the register, but 15104 gcc continues to use the register as if it was not clobbered 15105 * [154]13803 [coldfire] movqi operand constraints too restrictivefor 15106 TARGET_COLDFIRE 15107 * [155]14093 [SH] ICE for code when using -mhitachi option in SH 15108 * [156]14457 [m6811hc] ICE with simple c++ source 15109 * [157]14542 [m6811hc] ICE on simple source 15110 * [158]15100 [SH] cc1plus got hang-up on 15111 libstdc++-v3/testsuite/abi_check.cc 15112 * [159]15296 [CRIS] Delayed branch scheduling causing invalid code on 15113 cris-* 15114 * [160]15396 [SH] ICE with -O2 -fPIC 15115 * [161]15782 [coldfire] m68k_output_mi_thunk emits wrong code for 15116 ColdFire 15117 15118 Testsuite problems (compiler not affected) 15119 15120 * [162]11610 libstdc++ testcases 27_io/* don't work properly remotely 15121 * [163]15488 (libstdc++) possibly insufficient file permissions for 15122 executing test suite 15123 * [164]15489 (libstdc++) testsuite_files determined incorrectly 15124 15125 Documentation bugs 15126 15127 * [165]13928 (libstdc++) no whatis info in some man pages generated 15128 by doxygen 15129 * [166]14150 Ada documentation out of date 15130 * [167]14949 (c++) Need to document method visibility changes 15131 * [168]15123 libstdc++-doc: Allocators.3 manpage is empty 15132 __________________________________________________________________ 15133 15134 GCC 3.4.2 15135 15136 Bug Fixes 15137 15138 This section lists the problem reports (PRs) from GCC's bug tracking 15139 system that are known to be fixed in the 3.4.2 release. This list might 15140 not be complete (that is, it is possible that some PRs that have been 15141 fixed are not listed here). 15142 15143 Bootstrap failures and issues 15144 15145 * [169]16469 [mips-sgi-irix5.3] bootstrap fails in 15146 libstdc++-v3/testsuite 15147 * [170]16344 [hppa-linux-gnu] libstdc++'s PCH built by 15148 profiledbootstrap does not work with the built compiler 15149 * [171]16842 [Solaris/x86] mkheaders can not find mkheaders.conf 15150 15151 Multi-platform internal compiler errors (ICEs) 15152 15153 * [172]12608 (c++) ICE: expected class 't', have 'x' (error_mark) in 15154 cp_parser_class_specifier, in cp/parser.c 15155 * [173]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 15156 * [174]15461 (c++) ICE due to NRV and inlining 15157 * [175]15890 (c++) ICE in c_expand_expr, in c-common.c 15158 * [176]16180 ICE: segmentation fault in RTL optimization 15159 * [177]16224 (c++) ICE in write_unscoped_name (template/namespace) 15160 * [178]16408 ICE: in delete_insn, in cfgrtl.c 15161 * [179]16529 (c++) ICE for: namespace-alias shall not be declared as 15162 the name of any other entity 15163 * [180]16698 (c++) ICE with exceptions and declaration of __cxa_throw 15164 * [181]16706 (c++) ICE in finish_member_declaration, in 15165 cp/semantics.c 15166 * [182]16810 (c++) Legal C++ program with cast gives ICE in 15167 build_ptrmemfunc 15168 * [183]16851 (c++) ICE when throwing a comma expression 15169 * [184]16870 (c++) Boost.Spirit causes ICE in tsubst, in cp/pt.c 15170 * [185]16904 (c++) ICE in finish_class_member_access_expr, in 15171 cp/typeck.c 15172 * [186]16905 (c++) ICE (segfault) with exceptions 15173 * [187]16964 (c++) ICE in cp_parser_class_specifier due to 15174 redefinition 15175 * [188]17068 (c++) ICE: tree check: expected class 'd', have 'x' 15176 (identifier_node) in dependent_template_p, in cp/pt.c 15177 15178 Preprocessor bugs 15179 15180 * [189]16366 Preprocessor option -remap causes memory corruption 15181 15182 Optimization 15183 15184 * [190]15345 unreferenced nested inline functions not optimized away 15185 * [191]16590 Incorrect execution when compiling with -O2 15186 * [192]16693 Bitwise AND is lost when used within a cast to an enum 15187 of the same precision 15188 * [193]17078 Jump into if(0) substatement fails 15189 15190 Problems in generated debug information 15191 15192 * [194]13956 incorrect stabs for nested local variables 15193 15194 C front end bugs 15195 15196 * [195]16684 GCC should not warn about redundant redeclarations of 15197 built-ins 15198 15199 C++ compiler and library 15200 15201 * [196]12658 Thread safety problems in locale::global() and 15202 locale::locale() 15203 * [197]13092 g++ accepts invalid pointer-to-member conversion 15204 * [198]15320 Excessive memory consumption 15205 * [199]16246 Incorrect template argument deduction 15206 * [200]16273 Memory exhausted when using nested classes and virtual 15207 functions 15208 * [201]16401 ostringstream in gcc 3.4.x very slow for big data 15209 * [202]16411 undefined reference to 15210 __gnu_cxx::stdio_sync_filebuf<char, std::char_traits<char> 15211 >::file() 15212 * [203]16489 G++ incorrectly rejects use of a null constant integral 15213 expression as a null constant pointer 15214 * [204]16618 offsetof fails with constant member 15215 * [205]16637 syntax error reported for valid input code 15216 * [206]16717 __attribute__((constructor)) broken in C++ 15217 * [207]16813 compiler error in DEBUG version of range insertion 15218 std::map::insert 15219 * [208]16853 pointer-to-member initialization from incompatible one 15220 accepted 15221 * [209]16889 ambiguity is not detected 15222 * [210]16959 Segmentation fault in ios_base::sync_with_stdio 15223 15224 Java compiler and library 15225 15226 * [211]7587 direct threaded interpreter not thread-safe 15227 * [212]16473 ServerSocket accept() leaks file descriptors 15228 * [213]16478 Hash synchronization deadlock with finalizers 15229 15230 Alpha-specific 15231 15232 * [214]10695 ICE in dwarf2out_frame_debug_expr, in dwarf2out.c 15233 * [215]16974 could not split insn (ice in final_scan_insn, in 15234 final.c) 15235 15236 x86-specific 15237 15238 * [216]16298 ICE in output_operand 15239 * [217]17113 ICE with SSE2 intrinsics 15240 15241 x86-64 specific 15242 15243 * [218]14697 libstdc++ couldn't find 32bit libgcc_s 15244 15245 MIPS-specific 15246 15247 * [219]15869 [mips64] No NOP after LW (with -mips1 -O0) 15248 * [220]16325 [mips64] value profiling clobbers gp on mips 15249 * [221]16357 [mipsisa64-elf] ICE copying 7 bytes between extern 15250 char[]s 15251 * [222]16380 [mips64] Use of uninitialised register after dbra 15252 conversion 15253 * [223]16407 [mips64] Unaligned access to local variables 15254 * [224]16643 [mips64] verify_local_live_at_start ICE after 15255 crossjumping & cfgcleanup 15256 15257 ARM-specific 15258 15259 * [225]15927 THUMB -O2: strength-reduced iteration variable ends up 15260 off by 1 15261 * [226]15948 THUMB: ICE with non-commutative cbranch 15262 * [227]17019 THUMB: bad switch statement in md code for 15263 addsi3_cbranch_scratch 15264 15265 IA64-specific 15266 15267 * [228]16130 ICE on valid code: in bundling, in config/ia64/ia64.c 15268 (-mtune=merced) 15269 * [229]16142 ICE on valid code: in bundling, in config/ia64/ia64.c 15270 (-mtune=itanium) 15271 * [230]16278 Gcc failed to build Linux kernel with -mtune=merced 15272 * [231]16414 ICE on valid code: typo in comparison of asm_noperands 15273 result 15274 * [232]16445 ICE on valid code: don't count ignored insns 15275 * [233]16490 ICE (segfault) while compiling with -fprofile-use 15276 * [234]16683 ia64 does not honor SUBTARGET_EXTRA_SPECS 15277 15278 PowerPC-specific 15279 15280 * [235]16195 (ppc64): Miscompilation of GCC 3.3.x by 3.4.x 15281 * [236]16239 ICE on ppc64 (mozilla 1.7 compile, -O1 -fno-exceptions 15282 issue) 15283 15284 SPARC-specific 15285 15286 * [237]16199 ICE while compiling apache 2.0.49 15287 * [238]16416 -m64 doesn't imply -mcpu=v9 anymore 15288 * [239]16430 ICE when returning non-C aggregates larger than 16 bytes 15289 15290 Bugs specific to embedded processors 15291 15292 * [240]16379 [m32r] can't output large model function call of memcpy 15293 * [241]17093 [m32r] ICE with -msdata=use -O0 15294 * [242]17119 [m32r] ICE at switch case 0x8000 15295 15296 DJGPP-specific 15297 15298 * [243]15928 libstdc++ in 3.4.x doesn't cross-compile for djgpp 15299 15300 Alpha Tru64-specific 15301 15302 * [244]16210 libstdc++ gratuitously omits "long long" I/O 15303 15304 Testsuite, documentation issues (compiler is not affected): 15305 15306 * [245]15488 (libstdc++) possibly insufficient file permissions for 15307 executing test suite 15308 * [246]16250 ada/doctools runs makeinfo even in release tarball 15309 __________________________________________________________________ 15310 15311 GCC 3.4.3 15312 15313 This is the [247]list of problem reports (PRs) from GCC's bug tracking 15314 system that are known to be fixed in the 3.4.3 release. This list might 15315 not be complete (that is, it is possible that some PRs that have been 15316 fixed are not listed here). 15317 15318 Bootstrap failures 15319 15320 * [248]17369 [ia64] Bootstrap failure with binutils-2.15.90.0.1.1 15321 * [249]17850 [arm-elf] bootstrap failure - libstdc++ uses strtold 15322 when undeclared 15323 15324 Internal compiler errors (ICEs) affecting multiple platforms 15325 15326 * [250]13948 (java) GCJ segmentation fault while compiling GL4Java 15327 .class files 15328 * [251]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 15329 * [252]16301 (c++) ICE when "strong" attribute is attached to a using 15330 directive 15331 * [253]16566 ICE with flexible arrays 15332 * [254]17023 ICE with nested functions in parameter declaration 15333 * [255]17027 ICE with noreturn function in loop at -O2 15334 * [256]17524 ICE in grokdeclarator, in cp/decl.c 15335 * [257]17826 (c++) ICE in cp_tree_equal 15336 15337 C and optimization bugs 15338 15339 * [258]15526 -ftrapv aborts on 0 * (-1) 15340 * [259]16999 #ident stopped working 15341 * [260]17503 quadratic behaviour in invalid_mode_change_p 15342 * [261]17581 Long long arithmetic fails inside a switch/case 15343 statement when compiled with -O2 15344 * [262]18129 -fwritable-strings doesn't work 15345 15346 C++ compiler and library bugs 15347 15348 * [263]10975 incorrect initial ostringstream::tellp() 15349 * [264]11722 Unbuffered filebuf::sgetn is slow 15350 * [265]14534 Unrecognizing static function as a template parameter 15351 when its return value is also templated 15352 * [266]15172 Copy constructor optimization in aggregate 15353 initialization 15354 * [267]15786 Bad error message for frequently occuring error. 15355 * [268]16162 Rejects valid member-template-definition 15356 * [269]16612 empty basic_strings can't live in shared memory 15357 * [270]16715 std::basic_iostream is instantiated when used, even 15358 though instantiations are already contained in libstdc++ 15359 * [271]16848 code in /ext/demangle.h appears broken 15360 * [272]17132 GCC fails to eliminate function template specialization 15361 when argument deduction fails 15362 * [273]17259 One more _S_leaf incorrectly qualified with _RopeRep:: 15363 in ropeimpl.h 15364 * [274]17327 use of `enumeral_type' in template type unification 15365 * [275]17393 "unused variable '._0'" warning with -Wall 15366 * [276]17501 Confusion with member templates 15367 * [277]17537 g++ not passing -lstdc++ to linker when all command line 15368 arguments are libraries 15369 * [278]17585 usage of unqualified name of static member from within 15370 class not allowed 15371 * [279]17821 Poor diagnostic for using "." instead of "->" 15372 * [280]17829 wrong error: call of overloaded function is ambiguous 15373 * [281]17851 Misleading diagnostic for invalid function declarations 15374 with undeclared types 15375 * [282]17976 Destructor is called twice 15376 * [283]18020 rejects valid definition of enum value in template 15377 * [284]18093 bogus conflict in namespace aliasing 15378 * [285]18140 C++ parser bug when using >> in templates 15379 15380 Fortran 15381 15382 * [286]17541 data statements with double precision constants fail 15383 15384 x86-specific 15385 15386 * [287]17853 -O2 ICE for MMX testcase 15387 15388 SPARC-specific 15389 15390 * [288]17245 ICE compiling gsl-1.5 statistics/lag1.c 15391 15392 Darwin-specific 15393 15394 * [289]17167 FATAL:Symbol L_foo$stub already defined. 15395 15396 AIX-specific 15397 15398 * [290]17277 could not catch an exception when specified -maix64 15399 15400 Solaris-specific 15401 15402 * [291]17505 <cmath> calls acosf(), ceilf(), and other functions 15403 missing from system libraries 15404 15405 HP/UX specific: 15406 15407 * [292]17684 /usr/ccs/bin/ld: Can't create libgcc_s.sl 15408 15409 ARM-specific 15410 15411 * [293]17384 ICE with mode attribute on structures 15412 15413 MIPS-specific 15414 15415 * [294]17770 No NOP after LWL with -mips1 15416 15417 Other embedded target specific 15418 15419 * [295]11476 [arc-elf] gcc ICE on newlib's vfprintf.c 15420 * [296]14064 [avr-elf] -fdata-sections triggers ICE 15421 * [297]14678 [m68hc11-elf] gcc ICE 15422 * [298]15583 [powerpc-rtems] powerpc-rtems lacks __USE_INIT_FINI__ 15423 * [299]15790 [i686-coff] Alignment error building gcc with i686-coff 15424 target 15425 * [300]15886 [SH] Miscompilation with -O2 -fPIC 15426 * [301]16884 [avr-elf] [fweb related] bug while initializing 15427 variables 15428 15429 Bugs relating to debugger support 15430 15431 * [302]13841 missing debug info for _Complex function arguments 15432 * [303]15860 [big-endian targets] No DW_AT_location debug info is 15433 emitted for formal arguments to a function that uses "register" 15434 qualifiers 15435 15436 Testsuite issues (compiler not affected) 15437 15438 * [304]17465 Testsuite in libffi overrides LD_LIBRARY_PATH 15439 * [305]17469 Testsuite in libstdc++ overrides LD_LIBRARY_PATH 15440 * [306]18138 [mips-sgi-irix6.5] libgcc_s.so.1 not found by 64-bit 15441 testsuite 15442 15443 Documentation 15444 15445 * [307]15498 typo in gcc manual: non-existing locale example en_UK, 15446 should be en_GB 15447 * [308]15747 [mips-sgi-irix5.3] /bin/sh hangs during bootstrap: 15448 document broken shell 15449 * [309]16406 USE_LD_AS_NEEDED undocumented 15450 __________________________________________________________________ 15451 15452 GCC 3.4.4 15453 15454 This is the [310]list of problem reports (PRs) from GCC's bug tracking 15455 system that are known to be fixed in the 3.4.4 release. This list might 15456 not be complete (that is, it is possible that some PRs that have been 15457 fixed are not listed here). 15458 __________________________________________________________________ 15459 15460 GCC 3.4.5 15461 15462 This is the [311]list of problem reports (PRs) from GCC's bug tracking 15463 system that are known to be fixed in the 3.4.5 release. This list might 15464 not be complete (that is, it is possible that some PRs that have been 15465 fixed are not listed here). 15466 15467 Bootstrap issues 15468 15469 * [312]24688 sco_math fixincl breaks math.h 15470 15471 C compiler bugs 15472 15473 * [313]17188 struct Foo { } redefinition 15474 * [314]20187 wrong code for ((unsigned char)(unsigned long 15475 long)((a?a:1)&(a*b)))?0:1) 15476 * [315]21873 infinite warning loop on bad array initializer 15477 * [316]21899 enum definition accepts values to be overriden 15478 * [317]22061 ICE in find_function_data, in function.c 15479 * [318]22308 Failure to diagnose violation of constraint 6.516p2 15480 * [319]22458 ICE on missing brace 15481 * [320]22589 ICE casting to long long 15482 * [321]24101 Segfault with preprocessed source 15483 15484 C++ compiler and library bugs 15485 15486 * [322]10611 operations on vector mode not recognized in C++ 15487 * [323]13377 unexpected behavior of namespace usage directive 15488 * [324]16002 Strange error message with new parser 15489 * [325]17413 local classes as template argument 15490 * [326]17609 spurious error message after using keyword 15491 * [327]17618 ICE in cp_convert_to_pointer, in cp/cvt.c 15492 * [328]18124 ICE with invalid template template parameter 15493 * [329]18155 typedef in template declaration not rejected 15494 * [330]18177 ICE with const_cast for undeclared variable 15495 * [331]18368 C++ error message regression 15496 * [332]16378 ICE when returning a copy of a packed member 15497 * [333]18466 int ::i; accepted 15498 * [334]18512 ICE on invalid usage of template base class 15499 * [335]18454 ICE when returning undefined type 15500 * [336]18738 typename not allowed with non-dependent qualified name 15501 * [337]18803 rejects access to operator() in template 15502 * [338]19004 ICE in uses_template_parms, in cp/pt.c 15503 * [339]19208 Spurious error about variably modified type 15504 * [340]18253 bad error message / ICE for invalid template parameter 15505 * [341]19608 ICE after friend function definition in local class 15506 * [342]19884 ICE on explicit instantiation of a non-template 15507 constructor 15508 * [343]20153 ICE when C++ template function contains anonymous union 15509 * [344]20563 Infinite loop in diagnostic (and ice after error 15510 message) 15511 * [345]20789 ICE with incomplete type in template 15512 * [346]21336 Internal compiler error when using custom new operators 15513 * [347]21768 ICE in error message due to violation of coding 15514 conventions 15515 * [348]21853 constness of pointer to data member ignored 15516 * [349]21903 Default argument of template function causes a 15517 compile-time error 15518 * [350]21983 multiple diagnostics 15519 * [351]21987 New testsuite failure 15520 g++.dg/warn/conversion-function-1.C 15521 * [352]22153 ICE on invalid template specialization 15522 * [353]22172 Internal compiler error, seg fault. 15523 * [354]21286 filebuf::xsgetn vs pipes 15524 * [355]22233 ICE with wrong number of template parameters 15525 * [356]22508 ICE after invalid operator new 15526 * [357]22545 ICE with pointer to class member & user defined 15527 conversion operator 15528 * [358]23528 Wrong default allocator in ext/hash_map 15529 * [359]23550 char_traits requirements/1.cc test bad math 15530 * [360]23586 Bad diagnostic for invalid namespace-name 15531 * [361]23624 ICE in invert_truthvalue, in fold-const.c 15532 * [362]23639 Bad error message: not a member of '<declaration error>' 15533 * [363]23797 ICE on typename outside template 15534 * [364]23965 Bogus error message: no matching function for call to 15535 'foo(<type error>)' 15536 * [365]24052 &#`label_decl' not supported by dump_expr#<expression 15537 error> 15538 * [366]24580 virtual base class cause exception not to be caught 15539 15540 Problems in generated debug information 15541 15542 * [367]24267 Bad DWARF for altivec vectors 15543 15544 Optimizations issues 15545 15546 * [368]17810 ICE in verify_local_live_at_start 15547 * [369]17860 Wrong generated code for loop with varying bound 15548 * [370]21709 ICE on compile-time complex NaN 15549 * [371]21964 broken tail call at -O2 or more 15550 * [372]22167 Strange optimization bug when using -Os 15551 * [373]22619 Compilation failure for real_const_1.f and 15552 real_const_2.f90 15553 * [374]23241 Invalid code generated for comparison of uchar to 255 15554 * [375]23478 Miscompilation due to reloading of a var that is also 15555 used in EH pad 15556 * [376]24470 segmentation fault in cc1plus when compiling with -O 15557 * [377]24950 ICE in operand_subword_force 15558 15559 Precompiled headers problems 15560 15561 * [378]14400 Cannot compile qt-x11-free-3.3.0 15562 * [379]14940 PCH largefile test fails on various platforms 15563 15564 Preprocessor bugs 15565 15566 * [380]20239 ICE on empty preprocessed input 15567 * [381]15220 "gcc -E -MM -MG" reports missing system headers in 15568 source directory 15569 15570 Testsuite issues 15571 15572 * [382]19275 gcc.dg/20020919-1.c fails with -fpic/-fPIC on 15573 i686-pc-linux-gnu 15574 15575 Alpha specific 15576 15577 * [383]21888 bootstrap failure with linker relaxation enabled 15578 15579 ARM specific 15580 15581 * [384]15342 [arm-linux]: ICE in verify_local_live_at_start 15582 * [385]23985 Memory aliasing information incorrect in inlined memcpy 15583 15584 ColdFile specific 15585 15586 * [386]16719 Illegal move of byte into address register causes 15587 compiler to ICE 15588 15589 HPPA specific 15590 15591 * [387]21723 ICE while building libgfortran 15592 * [388]21841 -mhp-ld/-mgnu-ld documentation 15593 15594 IA-64 specific 15595 15596 * [389]23644 IA-64 hardware models and configuration options 15597 documentation error 15598 * [390]24718 Shared libgcc not used for linking by default 15599 15600 M68000 specific 15601 15602 * [391]18421 ICE in reload_cse_simplify_operands, in postreload.c 15603 15604 MIPS specific 15605 15606 * [392]20621 ICE in change_address_1, in emit-rtl.c 15607 15608 PowerPC and PowerPC64 specific 15609 15610 * [393]18583 error on valid code: const 15611 __attribute__((altivec(vector__))) doesn't work in arrays 15612 * [394]20191 ICE in reload_cse_simplify_operands 15613 * [395]22083 AIX: TARGET_C99_FUNCTIONS is wrongly defined 15614 * [396]23070 CALL_V4_CLEAR_FP_ARGS flag not properly set 15615 * [397]23404 gij trashes args of functions with more than 8 fp args 15616 * [398]23539 C & C++ compiler generating misaligned references 15617 regardless of compiler flags 15618 * [399]24102 floatdisf2_internal2 broken 15619 * [400]24465 -mminimal-toc miscompilation of __thread vars 15620 15621 Solaris specific 15622 15623 * [401]19933 Problem with define of HUGE_VAL in math_c99 15624 * [402]21889 Native Solaris assembler cannot grok DTP-relative debug 15625 symbols 15626 15627 SPARC specific 15628 15629 * [403]19300 PCH failures on sparc-linux 15630 * [404]20301 Assembler labels have a leading "-" 15631 * [405]20673 C PCH testsuite assembly comparison failure 15632 15633 x86 and x86_64 specific 15634 15635 * [406]18582 ICE with arrays of type V2DF 15636 * [407]19340 Compilation SEGFAULTs with -O1 -fschedule-insns2 15637 -fsched2-use-traces 15638 * [408]21716 ICE in reg-stack.c's swap_rtx_condition 15639 * [409]24315 amd64 fails -fpeephole2 15640 __________________________________________________________________ 15641 15642 GCC 3.4.6 15643 15644 This is the [410]list of problem reports (PRs) from GCC's bug tracking 15645 system that are known to be fixed in the 3.4.6 release. This list might 15646 not be complete (that is, it is possible that some PRs that have been 15647 fixed are not listed here). 15648 15649 15650 For questions related to the use of GCC, please consult these web 15651 pages and the [411]GCC manuals. If that fails, the 15652 [412]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15653 web pages and the development of GCC are welcome on our developer 15654 list at [413]gcc (a] gcc.gnu.org. All of [414]our lists have public 15655 archives. 15656 15657 Copyright (C) [415]Free Software Foundation, Inc. Verbatim copying and 15658 distribution of this entire article is permitted in any medium, 15659 provided this notice is preserved. 15660 15661 These pages are [416]maintained by the GCC team. Last modified 15662 2021-07-28[417]. 15663 15664 References 15665 15666 1. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6 15667 2. http://gcc.gnu.org/gcc-3.4/changes.html#cplusplus 15668 3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems 15669 4. http://gcc.gnu.org/gcc-3.4/changes.html#obsolete_systems 15670 5. http://gcc.gnu.org/gcc-3.4/mips-abi.html 15671 6. http://gcc.gnu.org/gcc-3.4/sparc-abi.html 15672 7. https://www.boost.org/ 15673 8. https://gcc.gnu.org/PR11953 15674 9. https://gcc.gnu.org/PR8361 15675 10. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Other-Builtins.html#Other Builtins 15676 11. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_closed.html#209 15677 12. http://gcc.gnu.org/bugs/#cxx_rvalbind 15678 13. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 15679 14. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 15680 15. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html 15681 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331. https://gcc.gnu.org/PR18368 15997 332. https://gcc.gnu.org/PR18378 15998 333. https://gcc.gnu.org/PR18466 15999 334. https://gcc.gnu.org/PR18512 16000 335. https://gcc.gnu.org/PR18545 16001 336. https://gcc.gnu.org/PR18738 16002 337. https://gcc.gnu.org/PR18803 16003 338. https://gcc.gnu.org/PR19004 16004 339. https://gcc.gnu.org/PR19208 16005 340. https://gcc.gnu.org/PR19253 16006 341. https://gcc.gnu.org/PR19608 16007 342. https://gcc.gnu.org/PR19884 16008 343. https://gcc.gnu.org/PR20153 16009 344. https://gcc.gnu.org/PR20563 16010 345. https://gcc.gnu.org/PR20789 16011 346. https://gcc.gnu.org/PR21336 16012 347. https://gcc.gnu.org/PR21768 16013 348. https://gcc.gnu.org/PR21853 16014 349. https://gcc.gnu.org/PR21903 16015 350. https://gcc.gnu.org/PR21983 16016 351. https://gcc.gnu.org/PR21987 16017 352. https://gcc.gnu.org/PR22153 16018 353. https://gcc.gnu.org/PR22172 16019 354. https://gcc.gnu.org/PR21286 16020 355. https://gcc.gnu.org/PR22233 16021 356. 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https://gcc.gnu.org/PR18582 16072 407. https://gcc.gnu.org/PR19340 16073 408. https://gcc.gnu.org/PR21716 16074 409. https://gcc.gnu.org/PR24315 16075 410. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.6 16076 411. https://gcc.gnu.org/onlinedocs/ 16077 412. mailto:gcc-help (a] gcc.gnu.org 16078 413. mailto:gcc (a] gcc.gnu.org 16079 414. https://gcc.gnu.org/lists.html 16080 415. https://www.fsf.org/ 16081 416. https://gcc.gnu.org/about.html 16082 417. http://validator.w3.org/check/referer 16083 ====================================================================== 16084 http://gcc.gnu.org/gcc-3.3/index.html 16085 GCC 3.3 Release Series 16086 16087 (This release series is no longer supported.) 16088 16089 May 03, 2005 16090 16091 The [1]GNU project and the GCC developers are pleased to announce the 16092 release of GCC 3.3.6. 16093 16094 This release is a bug-fix release, containing fixes for regressions in 16095 GCC 3.3.5 relative to previous releases of GCC. 16096 16097 This release is the last of the series 3.3.x. 16098 16099 The GCC 3.3 release series includes numerous [2]new features, 16100 improvements, bug fixes, and other changes, thanks to an [3]amazing 16101 group of volunteers. 16102 16103 Release History 16104 16105 GCC 3.3.6 16106 May 3, 2005 ([4]changes) 16107 16108 GCC 3.3.5 16109 September 30, 2004 ([5]changes) 16110 16111 GCC 3.3.4 16112 May 31, 2004 ([6]changes) 16113 16114 GCC 3.3.3 16115 February 14, 2004 ([7]changes) 16116 16117 GCC 3.3.2 16118 October 16, 2003 ([8]changes) 16119 16120 GCC 3.3.1 16121 August 8, 2003 ([9]changes) 16122 16123 GCC 3.3 16124 May 14, 2003 ([10]changes) 16125 16126 References and Acknowledgements 16127 16128 GCC used to stand for the GNU C Compiler, but since the compiler 16129 supports several other languages aside from C, it now stands for the 16130 GNU Compiler Collection. 16131 16132 A list of [11]successful builds is updated as new information becomes 16133 available. 16134 16135 The GCC developers would like to thank the numerous people that have 16136 contributed new features, improvements, bug fixes, and other changes as 16137 well as test results to GCC. This [12]amazing group of volunteers is 16138 what makes GCC successful. 16139 16140 For additional information about GCC please refer to the [13]GCC 16141 project web site or contact the [14]GCC development mailing list. 16142 16143 To obtain GCC please use [15]our mirror sites, or our CVS server. 16144 16145 16146 For questions related to the use of GCC, please consult these web 16147 pages and the [16]GCC manuals. If that fails, the 16148 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 16149 web pages and the development of GCC are welcome on our developer 16150 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 16151 archives. 16152 16153 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 16154 distribution of this entire article is permitted in any medium, 16155 provided this notice is preserved. 16156 16157 These pages are [21]maintained by the GCC team. Last modified 16158 2021-07-28[22]. 16159 16160 References 16161 16162 1. http://www.gnu.org/ 16163 2. http://gcc.gnu.org/gcc-3.3/changes.html 16164 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 16165 4. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 16166 5. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.5 16167 6. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.4 16168 7. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.3 16169 8. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.2 16170 9. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.1 16171 10. http://gcc.gnu.org/gcc-3.3/changes.html 16172 11. http://gcc.gnu.org/gcc-3.3/buildstat.html 16173 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 16174 13. http://gcc.gnu.org/index.html 16175 14. mailto:gcc (a] gcc.gnu.org 16176 15. http://gcc.gnu.org/mirrors.html 16177 16. https://gcc.gnu.org/onlinedocs/ 16178 17. mailto:gcc-help (a] gcc.gnu.org 16179 18. mailto:gcc (a] gcc.gnu.org 16180 19. https://gcc.gnu.org/lists.html 16181 20. https://www.fsf.org/ 16182 21. https://gcc.gnu.org/about.html 16183 22. http://validator.w3.org/check/referer 16184 ====================================================================== 16185 http://gcc.gnu.org/gcc-3.3/changes.html 16186 GCC 3.3 Release Series 16187 Changes, New Features, and Fixes 16188 16189 The latest release in the 3.3 release series is [1]GCC 3.3.6. 16190 16191 Caveats 16192 16193 * The preprocessor no longer accepts multi-line string literals. They 16194 were deprecated in 3.0, 3.1, and 3.2. 16195 * The preprocessor no longer supports the -A- switch when appearing 16196 alone. -A- followed by an assertion is still supported. 16197 * Support for all the systems [2]obsoleted in GCC 3.1 has been 16198 removed from GCC 3.3. See below for a [3]list of systems which are 16199 obsoleted in this release. 16200 * Checking for null format arguments has been decoupled from the rest 16201 of the format checking mechanism. Programs which use the format 16202 attribute may regain this functionality by using the new [4]nonnull 16203 function attribute. Note that all functions for which GCC has a 16204 built-in format attribute, an appropriate built-in nonnull 16205 attribute is also applied. 16206 * The DWARF (version 1) debugging format has been deprecated and will 16207 be removed in a future version of GCC. Version 2 of the DWARF 16208 debugging format will continue to be supported for the foreseeable 16209 future. 16210 * The C and Objective-C compilers no longer accept the "Naming Types" 16211 extension (typedef foo = bar); it was already unavailable in C++. 16212 Code which uses it will need to be changed to use the "typeof" 16213 extension instead: typedef typeof(bar) foo. (We have removed this 16214 extension without a period of deprecation because it has caused the 16215 compiler to crash since version 3.0 and no one noticed until very 16216 recently. Thus we conclude it is not in widespread use.) 16217 * The -traditional C compiler option has been removed. It was 16218 deprecated in 3.1 and 3.2. (Traditional preprocessing remains 16219 available.) The <varargs.h> header, used for writing variadic 16220 functions in traditional C, still exists but will produce an error 16221 message if used. 16222 * GCC 3.3.1 automatically places zero-initialized variables in the 16223 .bss section on some operating systems. Versions of GNU Emacs up to 16224 (and including) 21.3 will not work correctly when using this 16225 optimization; you can use -fno-zero-initialized-in-bss to disable 16226 it. 16227 16228 General Optimizer Improvements 16229 16230 * A new scheme for accurately describing processor pipelines, the 16231 [5]DFA scheduler, has been added. 16232 * Pavel Nejedly, Charles University Prague, has contributed new file 16233 format used by the edge coverage profiler (-fprofile-arcs). 16234 The new format is robust and diagnoses common mistakes where 16235 profiles from different versions (or compilations) of the program 16236 are combined resulting in nonsensical profiles and slow code to 16237 produced with profile feedback. Additionally this format allows 16238 extra data to be gathered. Currently, overall statistics are 16239 produced helping optimizers to identify hot spots of a program 16240 globally replacing the old intra-procedural scheme and resulting in 16241 better code. Note that the gcov tool from older GCC versions will 16242 not be able to parse the profiles generated by GCC 3.3 and vice 16243 versa. 16244 * Jan Hubicka, SuSE Labs, has contributed a new superblock formation 16245 pass enabled using -ftracer. This pass simplifies the control flow 16246 of functions allowing other optimizations to do better job. 16247 He also contributed the function reordering pass 16248 (-freorder-functions) to optimize function placement using profile 16249 feedback. 16250 16251 New Languages and Language specific improvements 16252 16253 C/ObjC/C++ 16254 16255 * The preprocessor now accepts directives within macro arguments. It 16256 processes them just as if they had not been within macro arguments. 16257 * The separate ISO and traditional preprocessors have been completely 16258 removed. The front end handles either type of preprocessed output 16259 if necessary. 16260 * In C99 mode preprocessor arithmetic is done in the precision of the 16261 target's intmax_t, as required by that standard. 16262 * The preprocessor can now copy comments inside macros to the output 16263 file when the macro is expanded. This feature, enabled using the 16264 -CC option, is intended for use by applications which place 16265 metadata or directives inside comments, such as lint. 16266 * The method of constructing the list of directories to be searched 16267 for header files has been revised. If a directory named by a -I 16268 option is a standard system include directory, the option is 16269 ignored to ensure that the default search order for system 16270 directories and the special treatment of system header files are 16271 not defeated. 16272 * A few more [6]ISO C99 features now work correctly. 16273 * A new function attribute, nonnull, has been added which allows 16274 pointer arguments to functions to be specified as requiring a 16275 non-null value. The compiler currently uses this information to 16276 issue a warning when it detects a null value passed in such an 16277 argument slot. 16278 * A new type attribute, may_alias, has been added. Accesses to 16279 objects with types with this attribute are not subjected to 16280 type-based alias analysis, but are instead assumed to be able to 16281 alias any other type of objects, just like the char type. 16282 16283 C++ 16284 16285 * Type based alias analysis has been implemented for C++ aggregate 16286 types. 16287 16288 Objective-C 16289 16290 * Generate an error if Objective-C objects are passed by value in 16291 function and method calls. 16292 * When -Wselector is used, check the whole list of selectors at the 16293 end of compilation, and emit a warning if a @selector() is not 16294 known. 16295 * Define __NEXT_RUNTIME__ when compiling for the NeXT runtime. 16296 * No longer need to include objc/objc-class.h to compile self calls 16297 in class methods (NeXT runtime only). 16298 * New -Wundeclared-selector option. 16299 * Removed selector bloating which was causing object files to be 10% 16300 bigger on average (GNU runtime only). 16301 * Using at run time @protocol() objects has been fixed in certain 16302 situations (GNU runtime only). 16303 * Type checking has been fixed and improved in many situations 16304 involving protocols. 16305 16306 Java 16307 16308 * The java.sql and javax.sql packages now implement the JDBC 3.0 (JDK 16309 1.4) API. 16310 * The JDK 1.4 assert facility has been implemented. 16311 * The bytecode interpreter is now direct threaded and thus faster. 16312 16313 Fortran 16314 16315 * Fortran improvements are listed in [7]the Fortran documentation. 16316 16317 Ada 16318 16319 * Ada tasking now works with glibc 2.3.x threading libraries. 16320 16321 New Targets and Target Specific Improvements 16322 16323 * The following changes have been made to the HP-PA port: 16324 + The port now defaults to scheduling for the PA8000 series of 16325 processors. 16326 + Scheduling support for the PA7300 processor has been added. 16327 + The 32-bit port now supports weak symbols under HP-UX 11. 16328 + The handling of initializers and finalizers has been improved 16329 under HP-UX 11. The 64-bit port no longer uses collect2. 16330 + Dwarf2 EH support has been added to the 32-bit GNU/Linux port. 16331 + ABI fixes to correct the passing of small structures by value. 16332 * The SPARC, HP-PA, SH4, and x86/pentium ports have been converted to 16333 use the DFA processor pipeline description. 16334 * The following NetBSD configurations for the SuperH processor family 16335 have been added: 16336 + SH3, big-endian, sh-*-netbsdelf* 16337 + SH3, little-endian, shle-*-netbsdelf* 16338 + SH5, SHmedia, big-endian, 32-bit default, sh5-*-netbsd* 16339 + SH5, SHmedia, little-endian, 32-bit default, sh5le-*-netbsd* 16340 + SH5, SHmedia, big-endian, 64-bit default, sh64-*-netbsd* 16341 + SH5, SHmedia, little-endian, 64-bit default, sh64le-*-netbsd* 16342 * The following changes have been made to the IA-32/x86-64 port: 16343 + SSE2 and 3dNOW! intrinsics are now supported. 16344 + Support for thread local storage has been added to the IA-32 16345 and x86-64 ports. 16346 + The x86-64 port has been significantly improved. 16347 * The following changes have been made to the MIPS port: 16348 + All configurations now accept the -mabi switch. Note that you 16349 will need appropriate multilibs for this option to work 16350 properly. 16351 + ELF configurations will always pass an ABI flag to the 16352 assembler, except when the MIPS EABI is selected. 16353 + -mabi=64 no longer selects MIPS IV code. 16354 + The -mcpu option, which was deprecated in 3.1 and 3.2, has 16355 been removed from this release. 16356 + -march now changes the core ISA level. In previous releases, 16357 it would change the use of processor-specific extensions, but 16358 would leave the core ISA unchanged. For example, mips64-elf 16359 -march=r8000 will now generate MIPS IV code. 16360 + Under most configurations, -mipsN now acts as a synonym for 16361 -march. 16362 + There are some new preprocessor macros to describe the -march 16363 and -mtune settings. See the documentation of those options 16364 for details. 16365 + Support for the NEC VR-Series processors has been added. This 16366 includes the 54xx, 5500, and 41xx series. 16367 + Support for the Sandcraft sr71k processor has been added. 16368 * The following changes have been made to the S/390 port: 16369 + Support to build the Java runtime libraries has been added. 16370 Java is now enabled by default on s390-*-linux* and 16371 s390x-*-linux* targets. 16372 + Multilib support for the s390x-*-linux* target has been added; 16373 this allows to build 31-bit binaries using the -m31 option. 16374 + Support for thread local storage has been added. 16375 + Inline assembler code may now use the 'Q' constraint to 16376 specify memory operands without index register. 16377 + Various platform-specific performance improvements have been 16378 implemented; in particular, the compiler now uses the BRANCH 16379 ON COUNT family of instructions and makes more frequent use of 16380 the TEST UNDER MASK family of instructions. 16381 * The following changes have been made to the PowerPC port: 16382 + Support for IBM Power4 processor added. 16383 + Support for Motorola e500 SPE added. 16384 + Support for AIX 5.2 added. 16385 + Function and Data sections now supported on AIX. 16386 + Sibcall optimizations added. 16387 * The support for H8 Tiny is added to the H8/300 port with -mn. 16388 16389 Obsolete Systems 16390 16391 Support for a number of older systems has been declared obsolete in GCC 16392 3.3. Unless there is activity to revive them, the next release of GCC 16393 will have their sources permanently removed. 16394 16395 All configurations of the following processor architectures have been 16396 declared obsolete: 16397 * Matsushita MN10200, mn10200-*-* 16398 * Motorola 88000, m88k-*-* 16399 * IBM ROMP, romp-*-* 16400 16401 Also, some individual systems have been obsoleted: 16402 * Alpha 16403 + Interix, alpha*-*-interix* 16404 + Linux libc1, alpha*-*-linux*libc1* 16405 + Linux ECOFF, alpha*-*-linux*ecoff* 16406 * ARM 16407 + Generic a.out, arm*-*-aout* 16408 + Conix, arm*-*-conix* 16409 + "Old ABI," arm*-*-oabi 16410 + StrongARM/COFF, strongarm-*-coff* 16411 * HPPA (PA-RISC) 16412 + Generic OSF, hppa1.0-*-osf* 16413 + Generic BSD, hppa1.0-*-bsd* 16414 + HP/UX versions 7, 8, and 9, hppa1.[01]-*-hpux[789]* 16415 + HiUX, hppa*-*-hiux* 16416 + Mach Lites, hppa*-*-lites* 16417 * Intel 386 family 16418 + Windows NT 3.x, i?86-*-win32 16419 * MC68000 family 16420 + HP systems, m68000-hp-bsd* and m68k-hp-bsd* 16421 + Sun systems, m68000-sun-sunos*, m68k-sun-sunos*, and 16422 m68k-sun-mach* 16423 + AT&T systems, m68000-att-sysv* 16424 + Atari systems, m68k-atari-sysv* 16425 + Motorola systems, m68k-motorola-sysv* 16426 + NCR systems, m68k-ncr-sysv* 16427 + Plexus systems, m68k-plexus-sysv* 16428 + Commodore systems, m68k-cbm-sysv* 16429 + Citicorp TTI, m68k-tti-* 16430 + Unos, m68k-crds-unos* 16431 + Concurrent RTU, m68k-ccur-rtu* 16432 + Linux a.out, m68k-*-linux*aout* 16433 + Linux libc1, m68k-*-linux*libc1* 16434 + pSOS, m68k-*-psos* 16435 * MIPS 16436 + Generic ECOFF, mips*-*-ecoff* 16437 + SINIX, mips-sni-sysv4 16438 + Orion RTEMS, mips64orion-*-rtems* 16439 * National Semiconductor 32000 16440 + OpenBSD, ns32k-*-openbsd* 16441 * POWER (aka RS/6000) and PowerPC 16442 + AIX versions 1, 2, and 3, rs6000-ibm-aix[123]* 16443 + Bull BOSX, rs6000-bull-bosx 16444 + Generic Mach, rs6000-*-mach* 16445 + Generic SysV, powerpc*-*-sysv* 16446 + Linux libc1, powerpc*-*-linux*libc1* 16447 * Sun SPARC 16448 + Generic a.out, sparc-*-aout*, sparclet-*-aout*, 16449 sparclite-*-aout*, and sparc86x-*-aout* 16450 + NetBSD a.out, sparc-*-netbsd*aout* 16451 + Generic BSD, sparc-*-bsd* 16452 + ChorusOS, sparc-*-chorusos* 16453 + Linux a.out, sparc-*-linux*aout* 16454 + Linux libc1, sparc-*-linux*libc1* 16455 + LynxOS, sparc-*-lynxos* 16456 + Solaris on HAL hardware, sparc-hal-solaris2* 16457 + SunOS versions 3 and 4, sparc-*-sunos[34]* 16458 * NEC V850 16459 + RTEMS, v850-*-rtems* 16460 * VAX 16461 + VMS, vax-*-vms* 16462 16463 Documentation improvements 16464 16465 Other significant improvements 16466 16467 * Almost all front-end dependencies in the compiler have been 16468 separated out into a set of language hooks. This should make adding 16469 a new front end clearer and easier. 16470 * One effect of removing the separate preprocessor is a small 16471 increase in the robustness of the compiler in general, and the 16472 maintainability of target descriptions. Previously target-specific 16473 built-in macros and others, such as __FAST_MATH__, had to be 16474 handled with so-called specs that were hard to maintain. Often they 16475 would fail to behave properly when conflicting options were 16476 supplied on the command line, and define macros in the user's 16477 namespace even when strict ISO compliance was requested. 16478 Integrating the preprocessor has cleanly solved these issues. 16479 * The Makefile suite now supports redirection of make install by 16480 means of the variable DESTDIR. 16481 __________________________________________________________________ 16482 16483 GCC 3.3 16484 16485 Detailed release notes for the GCC 3.3 release follow. 16486 16487 Bug Fixes 16488 16489 bootstrap failures 16490 16491 * [8]10140 cross compiler build failures: missing __mempcpy (DUP: 16492 [9]10198,[10]10338) 16493 16494 Internal compiler errors (multi-platform) 16495 16496 * [11]3581 large string causes segmentation fault in cc1 16497 * [12]4382 __builtin_{set,long}jmp with -O3 can crash the compiler 16498 * [13]5533 (c++) ICE when processing std::accumulate(begin, end, 16499 init, invalid_op) 16500 * [14]6387 -fpic -gdwarf-2 -g1 combination gives ICE in dwarf2out 16501 * [15]6412 (c++) ICE in retrieve_specialization 16502 * [16]6620 (c++) partial template specialization causes an ICE 16503 (segmentation fault) 16504 * [17]6663 (c++) ICE with attribute aligned 16505 * [18]7068 ICE with incomplete types 16506 * [19]7083 (c++) ICE using -gstabs with dodgy class derivation 16507 * [20]7647 (c++) ICE when data member has the name of the enclosing 16508 class 16509 * [21]7675 ICE in fixup_var_refs_1 16510 * [22]7718 'complex' template instantiation causes ICE 16511 * [23]8116 (c++) ICE in member template function 16512 * [24]8358 (ada) Ada compiler accesses freed memory, crashes 16513 * [25]8511 (c++) ICE: (hopefully) reproducible cc1plus segmentation 16514 fault 16515 * [26]8564 (c++) ICE in find_function_data, in function.c 16516 * [27]8660 (c++) template overloading ICE in tsubst_expr, in cp/pt.c 16517 * [28]8766 (c++) ICE after failed initialization of static template 16518 variable 16519 * [29]8803 ICE in instantiate_virtual_regs_1, in function.c 16520 * [30]8846 (c++) ICE after diagnostic if fr_FR@euro locale is set 16521 * [31]8906 (c++) ICE (Segmentation fault) when parsing nested-class 16522 definition 16523 * [32]9216 (c++) ICE on missing template parameter 16524 * [33]9261 (c++) ICE in arg_assoc, in cp/decl2.c 16525 * [34]9263 (fortran) ICE caused by invalid PARAMETER in implied DO 16526 loop 16527 * [35]9429 (c++) ICE in template instantiation with a pointered new 16528 operator 16529 * [36]9516 Internal error when using a big array 16530 * [37]9600 (c++) ICE with typedefs in template class 16531 * [38]9629 (c++) virtual inheritance segfault 16532 * [39]9672 (c++) ICE: Error reporting routines re-entered 16533 * [40]9749 (c++) ICE in write_expression on invalid function 16534 prototype 16535 * [41]9794 (fortran) ICE: floating point exception during constant 16536 folding 16537 * [42]9829 (c++) Missing colon in nested namespace usage causes ICE 16538 * [43]9916 (c++) ICE with noreturn function in ?: statement 16539 * [44]9936 ICE with local function and variable-length 2d array 16540 * [45]10262 (c++) cc1plus crashes with large generated code 16541 * [46]10278 (c++) ICE in parser for invalid code 16542 * [47]10446 (c++) ICE on definition of nonexistent member function of 16543 nested class in a class template 16544 * [48]10451 (c++) ICE in grokdeclarator on spurious mutable 16545 declaration 16546 * [49]10506 (c++) ICE in build_new at cp/init.c with 16547 -fkeep-inline-functions and multiple inheritance 16548 * [50]10549 (c++) ICE in store_bit_field on bitfields that exceed the 16549 precision of the declared type 16550 16551 Optimization bugs 16552 16553 * [51]2001 Inordinately long compile times in reload CSE regs 16554 * [52]2391 Exponential compilation time explosion in combine 16555 * [53]2960 Duplicate loop conditions even with -Os 16556 * [54]4046 redundant conditional branch 16557 * [55]6405 Loop-unrolling related performance regressions 16558 * [56]6798 very long compile time with large case-statement 16559 * [57]6871 const objects shouldn't be moved to .bss 16560 * [58]6909 problem w/ -Os on modified loop-2c.c test case 16561 * [59]7189 gcc -O2 -Wall does not print ``control reaches end of 16562 non-void function'' warning 16563 * [60]7642 optimization problem with signbit() 16564 * [61]8634 incorrect code for inlining of memcpy under -O2 16565 * [62]8750 Cygwin prolog generation erroneously emitting __alloca as 16566 regular function call 16567 16568 C front end 16569 16570 * [63]2161 long if-else cascade overflows parser stack 16571 * [64]4319 short accepted on typedef'd char 16572 * [65]8602 incorrect line numbers in warning messages when using 16573 inline functions 16574 * [66]9177 -fdump-translation-unit: C front end deletes function_decl 16575 AST nodes and breaks debugging dumps 16576 * [67]9853 miscompilation of non-constant structure initializer 16577 16578 c++ compiler and library 16579 16580 * [68]45 legal template specialization code is rejected (DUP: 16581 [69]3784) 16582 * [70]764 lookup failure: friend operator and dereferencing a pointer 16583 and templates (DUP: [71]5116) 16584 * [72]2862 gcc accepts invalid explicit instantiation syntax (DUP: 16585 2863) 16586 * [73]3663 G++ doesn't check access control during template 16587 instantiation 16588 * [74]3797 gcc fails to emit explicit specialization of a template 16589 member 16590 * [75]3948 Two destructors are called when no copy destructor is 16591 defined (ABI change) 16592 * [76]4137 Conversion operator within template is not accepted 16593 * [77]4361 bogus ambiguity taking the address of a member template 16594 * [78]4802 g++ accepts illegal template code (access to private 16595 member; DUP: [79]5837) 16596 * [80]4803 inline function is used but never defined, and g++ does 16597 not object 16598 * [81]5094 Partial specialization cannot be friend? 16599 * [82]5730 complex<double>::norm() -- huge slowdown from egcs-2.91.66 16600 * [83]6713 Regression wrt 3.0.4: g++ -O2 leads to seg fault at run 16601 time 16602 * [84]7015 certain __asm__ constructs rejected 16603 * [85]7086 compile time regression (quadratic behavior in 16604 fixup_var_refs) 16605 * [86]7099 G++ doesn't set the noreturn attribute on std::exit and 16606 std::abort 16607 * [87]7247 copy constructor missing when inlining enabled (invalid 16608 optimization?) 16609 * [88]7441 string array initialization compilation time regression 16610 from seconds to minutes 16611 * [89]7768 __PRETTY_FUNCTION__ for template destructor is wrong 16612 * [90]7804 bad printing of floating point constant in warning message 16613 * [91]8099 Friend classes and template specializations 16614 * [92]8117 member function pointers and multiple inheritance 16615 * [93]8205 using declaration and multiple inheritance 16616 * [94]8645 unnecessary non-zero checks in stl_tree.h 16617 * [95]8724 explicit destructor call for incomplete class allowed 16618 * [96]8805 compile time regression with many member variables 16619 * [97]8691 -O3 and -fno-implicit-templates are incompatible 16620 * [98]8700 unhelpful error message for binding temp to reference 16621 * [99]8724 explicit destructor call for incomplete class allowed 16622 * [100]8949 numeric_limits<>::denorm_min() and is_iec559 problems 16623 * [101]9016 Failure to consistently constant fold "constant" C++ 16624 objects 16625 * [102]9053 g++ confused about ambiguity of overloaded function 16626 templates 16627 * [103]9152 undefined virtual thunks 16628 * [104]9182 basic_filebuf<> does not report errors in codecvt<>::out 16629 * [105]9297 data corruption due to codegen bug (when copying.) 16630 * [106]9318 i/ostream::operator>>/<<(streambuf*) broken 16631 * [107]9320 Incorrect usage of traits_type::int_type in stdio_filebuf 16632 * [108]9400 bogus -Wshadow warning: shadowed declaration of this in 16633 local classes 16634 * [109]9424 i/ostream::operator>>/<<(streambuf*) drops characters 16635 * [110]9425 filebuf::pbackfail broken (DUP: [111]9439) 16636 * [112]9474 GCC freezes in compiling a weird code mixing <iostream> 16637 and <iostream.h> 16638 * [113]9548 Incorrect results from setf(ios::fixed) and precision(-1) 16639 [114][DR 231] 16640 * [115]9555 ostream inserters fail to set badbit on exception 16641 * [116]9561 ostream inserters rethrow exception of wrong type 16642 * [117]9563 ostream::sentry returns true after a failed preparation 16643 * [118]9582 one-definition rule violation in std::allocator 16644 * [119]9622 __PRETTY_FUNCTION__ incorrect in template destructors 16645 * [120]9683 bug in initialization chains for static const variables 16646 from template classes 16647 * [121]9791 -Woverloaded-virtual reports hiding of destructor 16648 * [122]9817 collate::compare doesn't handle nul characters 16649 * [123]9825 filebuf::sputbackc breaks sbumpc 16650 * [124]9826 operator>>(basic_istream, basic_string) fails to compile 16651 with custom traits 16652 * [125]9924 Multiple using statements for builtin functions not 16653 allowed 16654 * [126]9946 destructor is not called for temporary object 16655 * [127]9964 filebuf::close() sometimes fails to close file 16656 * [128]9988 filebuf::overflow writes EOF to file 16657 * [129]10033 optimization breaks polymorphic references w/ typeid 16658 operator 16659 * [130]10097 filebuf::underflow drops characters 16660 * [131]10132 filebuf destructor can throw exceptions 16661 * [132]10180 gcc fails to warn about non-inlined function 16662 * [133]10199 method parametrized by template does not work everywhere 16663 * [134]10300 use of array-new (nothrow) in segfaults on NULL return 16664 * [135]10427 Stack corruption with variable-length automatic arrays 16665 and virtual destructors 16666 * [136]10503 Compilation never stops in fixed_type_or_null 16667 16668 Objective-C 16669 16670 * [137]5956 selectors aren't matched properly when added to the 16671 selector table 16672 16673 Fortran compiler and library 16674 16675 * [138]1832 list directed i/o overflow hangs, -fbounds-check doesn't 16676 detect 16677 * [139]3924 g77 generates code that is rejected by GAS if COFF debug 16678 info requested 16679 * [140]5634 doc: explain that configure --prefix=~/... does not work 16680 * [141]6367 multiple repeat counts confuse namelist read into array 16681 * [142]6491 Logical operations error on logicals when using 16682 -fugly-logint 16683 * [143]6742 Generation of C++ Prototype for FORTRAN and extern "C" 16684 * [144]7113 Failure of g77.f-torture/execute/f90-intrinsic-bit.f -Os 16685 on irix6.5 16686 * [145]7236 OPEN(...,RECL=nnn,...) without ACCESS='DIRECT' should 16687 assume a direct access file 16688 * [146]7278 g77 "bug"; the executable misbehaves (with -O2 16689 -fno-automatic) 16690 * [147]7384 DATE_AND_TIME milliseconds field inactive on Windows 16691 * [148]7388 Incorrect output with 0-based array of characters 16692 * [149]8587 Double complex zero ** double precision number -> NaN 16693 instead of zero 16694 * [150]9038 -ffixed-line-length-none -x f77-cpp-input gives: Warning: 16695 unknown register name line-length-none 16696 * [151]10197 Direct access files not unformatted by default 16697 16698 Java compiler and library 16699 16700 * [152]6005 gcj fails to build rhug on alpha 16701 * [153]6389 System.getProperty("") should always throw an 16702 IllegalArgumentException 16703 * [154]6576 java.util.ResourceBundle.getResource ignores locale 16704 * [155]6652 new java.io.File("").getCanonicalFile() throws exception 16705 * [156]7060 getMethod() doesn't search super interface 16706 * [157]7073 bytecode interpreter gives wrong answer for interface 16707 getSuperclass() 16708 * [158]7180 possible bug in 16709 javax.naming.spi.NamingManager.getPlusPath() 16710 * [159]7416 java.security startup refs "GNU libgcj.security" 16711 * [160]7570 Runtime.exec with null envp: child doesn't inherit parent 16712 env (DUP: [161]7578) 16713 * [162]7611 Internal error while compiling libjava with -O 16714 * [163]7709 NullPointerException in _Jv_ResolvePoolEntry 16715 * [164]7766 ZipInputStream.available returns 0 immediately after 16716 construction 16717 * [165]7785 Calendar.getTimeInMillis/setTimeInMillis should be public 16718 * [166]7786 TimeZone.getDSTSavings() from JDK1.4 not implemented 16719 * [167]8142 '$' in class names vs. dlopen 'dynamic string tokens' 16720 * [168]8234 ZipInputStream chokes when InputStream.read() returns 16721 small chunks 16722 * [169]8415 reflection bug: exception info for Method 16723 * [170]8481 java.Random.nextInt(int) may return negative 16724 * [171]8593 Error reading GZIPped files with BufferedReader 16725 * [172]8759 java.beans.Introspector has no flushCaches() or 16726 flushFromCaches() methods 16727 * [173]8997 spin() calls Thread.sleep 16728 * [174]9253 on win32, java.io.File.listFiles("C:\\") returns pwd 16729 instead of the root content of C: 16730 * [175]9254 java::lang::Object::wait(), threads-win32.cc returns 16731 wrong return codes 16732 * [176]9271 Severe bias in java.security.SecureRandom 16733 16734 Ada compiler and library 16735 16736 * [177]6767 make gnatlib-shared fails on -laddr2line 16737 * [178]9911 gnatmake fails to link when GCC configured with 16738 --with-sjlj-exceptions=yes 16739 * [179]10020 Can't bootstrap gcc on AIX with Ada enabled 16740 * [180]10546 Ada tasking not working on Red Hat 9 16741 16742 preprocessor 16743 16744 * [181]7029 preprocessor should ignore #warning with -M 16745 16746 ARM-specific 16747 16748 * [182]2903 [arm] Optimization bug with long long arithmetic 16749 * [183]7873 arm-linux-gcc fails when assigning address to a bit field 16750 16751 FreeBSD-specific 16752 16753 * [184]7680 float functions undefined in math.h/cmath with #define 16754 _XOPEN_SOURCE 16755 16756 HP-UX or HP-PA-specific 16757 16758 * [185]8705 [HP-PA] ICE in emit_move_insn_1, in expr.c 16759 * [186]9986 [HP-UX] Incorrect transformation of fputs_unlocked to 16760 fputc_unlocked 16761 * [187]10056 [HP-PA] ICE at -O2 when building c++ code from doxygen 16762 16763 m68hc11-specific 16764 16765 * [188]6744 Bad assembler code generated: reference to pseudo 16766 register z 16767 * [189]7361 Internal compiler error in reload_cse_simplify_operands, 16768 in reload1.c 16769 16770 MIPS-specific 16771 16772 * [190]9496 [mips-linux] bug in optimizer? 16773 16774 PowerPC-specific 16775 16776 * [191]7067 -Os with -mcpu=powerpc optimizes for speed (?) instead of 16777 space 16778 * [192]8480 reload ICEs for LAPACK code on powerpc64-linux 16779 * [193]8784 [AIX] Internal compiler error in simplify_gen_subreg 16780 * [194]10315 [powerpc] ICE: in extract_insn, in recog.c 16781 16782 SPARC-specific 16783 16784 * [195]10267 (documentation) Wrong build instructions for 16785 *-*-solaris2* 16786 16787 x86-specific (Intel/AMD) 16788 16789 * [196]7916 ICE in instantiate_virtual_register_1 16790 * [197]7926 (c++) i486 instructions in header files make c++ programs 16791 crash on i386 16792 * [198]8555 ICE in gen_split_1231 16793 * [199]8994 ICE with -O -march=pentium4 16794 * [200]9426 ICE with -fssa -funroll-loops -fprofile-arcs 16795 * [201]9806 ICE in inline assembly with -fPIC flag 16796 * [202]10077 gcc -msse2 generates movd to move dwords between xmm 16797 regs 16798 * [203]10233 64-bit comparison only comparing bottom 32-bits 16799 * [204]10286 type-punning doesn't work with __m64 and -O 16800 * [205]10308 [x86] ICE with -O -fgcse or -O2 16801 __________________________________________________________________ 16802 16803 GCC 3.3.1 16804 16805 Bug Fixes 16806 16807 This section lists the problem reports (PRs) from GCC's bug tracking 16808 system that are known to be fixed in the 3.3.1 release. This list might 16809 not be complete (that is, it is possible that some PRs that have been 16810 fixed are not listed here). 16811 16812 Bootstrap failures 16813 16814 * [206]11272 [Solaris] make bootstrap fails while building libstdc++ 16815 16816 Internal compiler errors (multi-platform) 16817 16818 * [207]5754 ICE on invalid nested template class 16819 * [208]6597 ICE in set_mem_alias_set compiling Qt with -O2 on ia64 16820 and --enable-checking 16821 * [209]6949 (c++) ICE in tsubst_decl, in cp/pt.c 16822 * [210]7053 (c++) ICE when declaring a function already defined as a 16823 friend method of a template class 16824 * [211]8164 (c++) ICE when using different const expressions as 16825 template parameter 16826 * [212]8384 (c++) ICE in is_base_type, in dwarf2out.c 16827 * [213]9559 (c++) ICE with invalid initialization of a static const 16828 * [214]9649 (c++) ICE in finish_member_declaration, in cp/semantics.c 16829 when redeclaring a static member variable 16830 * [215]9864 (fortran) ICE in add_abstract_origin_attribute, in 16831 dwarfout.c with -g -O -finline-functions 16832 * [216]10432 (c++) ICE in poplevel, in cp/decl.c 16833 * [217]10475 ICE in subreg_highpart_offset for code with long long 16834 * [218]10635 (c++) ICE when dereferencing an incomplete type casted 16835 from a void pointer 16836 * [219]10661 (c++) ICE in instantiate_decl, in cp/pt.c while 16837 instantiating static member variables 16838 * [220]10700 ICE in copy_to_mode_reg on 64-bit targets 16839 * [221]10712 (c++) ICE in constructor_name_full, in cp/decl2.c 16840 * [222]10796 (c++) ICE when defining an enum with two values: -1 and 16841 MAX_INT_64BIT 16842 * [223]10890 ICE in merge_assigned_reloads building Linux 2.4.2x 16843 sched.c 16844 * [224]10939 (c++) ICE with template code 16845 * [225]10956 (c++) ICE when specializing a template member function 16846 of a template class, in tsubst, in cp/pt.c 16847 * [226]11041 (c++) ICE: const myclass &x = *x; (when operator*() 16848 defined) 16849 * [227]11059 (c++) ICE with empty union 16850 * [228]11083 (c++) ICE in commit_one_edge_insertion, in cfgrtl.c with 16851 -O2 -fnon-call-exceptions 16852 * [229]11105 (c++) ICE in mangle_conv_op_name_for_type 16853 * [230]11149 (c++) ICE on error when instantiation with call function 16854 of a base type 16855 * [231]11228 (c++) ICE on new-expression using array operator new and 16856 default-initialization 16857 * [232]11282 (c++) Infinite memory usage after syntax error 16858 * [233]11301 (fortran) ICE with -fno-globals 16859 * [234]11308 (c++) ICE when using an enum type name as if it were a 16860 class or namespace 16861 * [235]11473 (c++) ICE with -gstabs when empty struct inherits from 16862 an empty struct 16863 * [236]11503 (c++) ICE when instantiating template with ADDR_EXPR 16864 * [237]11513 (c++) ICE in push_template_decl_real, in cp/pt.c: 16865 template member functions 16866 16867 Optimization bugs 16868 16869 * [238]11198 -O2 -frename-registers generates wrong code (aliasing 16870 problem) 16871 * [239]11304 Wrong code production with -fomit-frame-pointer 16872 * [240]11381 volatile memory access optimized away 16873 * [241]11536 [strength-reduce] -O2 optimization produces wrong code 16874 * [242]11557 constant folding bug generates wrong code 16875 16876 C front end 16877 16878 * [243]5897 No warning for statement after return 16879 * [244]11279 DWARF-2 output mishandles large enums 16880 16881 Preprocessor bugs 16882 16883 * [245]11022 no warning for non-compatible macro redefinition 16884 16885 C++ compiler and library 16886 16887 * [246]2330 static_cast<>() to a private base is allowed 16888 * [247]5388 Incorrect message "operands to ?: have different types" 16889 * [248]5390 Libiberty fails to demangle multi-digit template 16890 parameters 16891 * [249]7877 Incorrect parameter passing to specializations of member 16892 function templates 16893 * [250]9393 Anonymous namespaces and compiling the same file twice 16894 * [251]10032 -pedantic converts some errors to warnings 16895 * [252]10468 const typeof(x) is non-const, but only in templates 16896 * [253]10527 confused error message with "new int()" parameter 16897 initializer 16898 * [254]10679 parameter MIN_INLINE_INSNS is not honored 16899 * [255]10682 gcc chokes on a typedef for an enum inside a class 16900 template 16901 * [256]10689 pow(std::complex(0),1/3) returns (nan, nan) instead of 16902 0. 16903 * [257]10845 template member function (with nested template as 16904 parameter) cannot be called anymore if another unrelated template 16905 member function is defined 16906 * [258]10849 Cannot define an out-of-class specialization of a 16907 private nested template class 16908 * [259]10888 Suppress -Winline warnings for system headers 16909 * [260]10929 -Winline warns about functions for which no definition 16910 is visible 16911 * [261]10931 valid conversion static_cast<const unsigned 16912 int&>(lvalue-of-type-int) is rejected 16913 * [262]10940 Bad code with explicit specialization 16914 * [263]10968 If member function implicitly instantiated, explicit 16915 instantiation of class fails to instantiate it 16916 * [264]10990 Cannot convert with dynamic_cast<> to a private base 16917 class from within a member function 16918 * [265]11039 Bad interaction between implicit typename deprecation 16919 and friendship 16920 * [266]11062 (libstdc++) avoid __attribute__ ((unused)); say 16921 "__unused__" instead 16922 * [267]11095 C++ iostream manipulator causes segfault when called 16923 with negative argument 16924 * [268]11098 g++ doesn't emit complete debugging information for 16925 local variables in destructors 16926 * [269]11137 GNU/Linux shared library constructors not called unless 16927 there's one global object 16928 * [270]11154 spurious ambiguity report for template class 16929 specialization 16930 * [271]11329 Compiler cannot find user defined implicit typecast 16931 * [272]11332 Spurious error with casts in ?: expression 16932 * [273]11431 static_cast behavior with subclasses when default 16933 constructor available 16934 * [274]11528 money_get facet does not accept "$.00" as valid 16935 * [275]11546 Type lookup problems in out-of-line definition of a 16936 class doubly nested from a template class 16937 * [276]11567 C++ code containing templated member function with same 16938 name as pure virtual member function results in linking failure 16939 * [277]11645 Failure to deal with using and private inheritance 16940 16941 Java compiler and library 16942 16943 * [278]5179 Qualified static field access doesn't initialize its 16944 class 16945 * [279]8204 gcj -O2 to native reorders certain instructions 16946 improperly 16947 * [280]10838 java.io.ObjectInputStream syntax error 16948 * [281]10886 The RMI registry that comes with GCJ does not work 16949 correctly 16950 * [282]11349 JNDI URL context factories not located correctly 16951 16952 x86-specific (Intel/AMD) 16953 16954 * [283]4823 ICE on inline assembly code 16955 * [284]8878 miscompilation with -O and SSE 16956 * [285]9815 (c++ library) atomicity.h - fails to compile with -O3 16957 -masm=intel 16958 * [286]10402 (inline assembly) [x86] ICE in merge_assigned_reloads, 16959 in reload1.c 16960 * [287]10504 ICE with SSE2 code and -O3 -mcpu=pentium4 -msse2 16961 * [288]10673 ICE for x86-64 on freebsd libc vfprintf.c source 16962 * [289]11044 [x86] out of range loop instructions for FP code on K6 16963 * [290]11089 ICE: instantiate_virtual_regs_lossage while using SSE 16964 built-ins 16965 * [291]11420 [x86_64] gcc generates invalid asm code when "-O -fPIC" 16966 is used 16967 16968 SPARC- or Solaris- specific 16969 16970 * [292]9362 solaris 'as' dies when fed .s and "-gstabs" 16971 * [293]10142 [SPARC64] gcc produces wrong code when passing 16972 structures by value 16973 * [294]10663 New configure check aborts with Sun tools. 16974 * [295]10835 combinatorial explosion in scheduler on HyperSPARC 16975 * [296]10876 ICE in calculate_giv_inc when building KDE 16976 * [297]10955 wrong code at -O3 for structure argument in context of 16977 structure return 16978 * [298]11018 -mcpu=ultrasparc busts tar-1.13.25 16979 * [299]11556 [sparc64] ICE in gen_reg_rtx() while compiling 2.6.x 16980 Linux kernel 16981 16982 ia64 specific 16983 16984 * [300]10907 gcc violates the ia64 ABI (GP must be preserved) 16985 * [301]11320 scheduler bug (in machine depended reorganization pass) 16986 * [302]11599 bug with conditional and __builtin_prefetch 16987 16988 PowerPC specific 16989 16990 * [303]9745 [powerpc] gcc mis-compiles libmcrypt (alias problem 16991 during loop) 16992 * [304]10871 error in rs6000_stack_info save_size computation 16993 * [305]11440 gcc mis-compiles c++ code (libkhtml) with -O2, -fno-gcse 16994 cures it 16995 16996 m68k-specific 16997 16998 * [306]7594 [m68k] ICE on legal code associated with simplify-rtx 16999 * [307]10557 [m68k] ICE in subreg_offset_representable_p 17000 * [308]11054 [m68k] ICE in reg_overlap_mentioned_p 17001 17002 ARM-specific 17003 17004 * [309]10834 [arm] GCC 3.3 still generates incorrect instructions for 17005 functions with __attribute__ ((interrupt ("IRQ"))) 17006 * [310]10842 [arm] Clobbered link register is copied to pc under 17007 certain circumstances 17008 * [311]11052 [arm] noce_process_if_block() can lose REG_INC notes 17009 * [312]11183 [arm] ICE in change_address_1 (3.3) / subreg_hard_regno 17010 (3.4) 17011 17012 MIPS-specific 17013 17014 * [313]11084 ICE in propagate_one_insn, in flow.c 17015 17016 SH-specific 17017 17018 * [314]10331 can't compile c++ part of gcc cross compiler for sh-elf 17019 * [315]10413 [SH] ICE in reload_cse_simplify_operands, in reload1.c 17020 * [316]11096 i686-linux to sh-linux cross compiler fails to compile 17021 C++ files 17022 17023 GNU/Linux (or Hurd?) specific 17024 17025 * [317]2873 Bogus fixinclude of stdio.h from glibc 2.2.3 17026 17027 UnixWare specific 17028 17029 * [318]3163 configure bug: gcc/aclocal.m4 mmap test fails on UnixWare 17030 7.1.1 17031 17032 Cygwin (or mingw) specific 17033 17034 * [319]5287 ICE with dllimport attribute 17035 * [320]10148 [MingW/CygWin] Compiler dumps core 17036 17037 DJGPP specific 17038 17039 * [321]8787 GCC fails to emit .intel_syntax when invoked with 17040 -masm=intel on DJGPP 17041 17042 Darwin (and MacOS X) specific 17043 17044 * [322]10900 trampolines crash 17045 17046 Documentation 17047 17048 * [323]1607 (c++) Format attributes on methods undocumented 17049 * [324]4252 Invalid option `-fdump-translation-unit' 17050 * [325]4490 Clarify restrictions on -m96bit-long-double, 17051 -m128bit-long-double 17052 * [326]10355 document an issue with regparm attribute on some systems 17053 (e.g. Solaris) 17054 * [327]10726 (fortran) Documentation for function "IDate Intrinsic 17055 (Unix)" is wrong 17056 * [328]10805 document bug in old version of Sun assembler 17057 * [329]10815 warn against GNU binutils on AIX 17058 * [330]10877 document need for newer binutils on i?86-*-linux-gnu 17059 * [331]11280 Manual incorrect with respect to -freorder-blocks 17060 * [332]11466 Document -mlittle-endian and its restrictions for the 17061 sparc64 port 17062 17063 Testsuite bugs (compiler itself is not affected) 17064 17065 * [333]10737 newer bison causes g++.dg/parse/crash2.C to incorrectly 17066 report failure 17067 * [334]10810 gcc-3.3 fails make check: buffer overrun in 17068 test_demangle.c 17069 __________________________________________________________________ 17070 17071 GCC 3.3.2 17072 17073 Bug Fixes 17074 17075 This section lists the problem reports (PRs) from GCC's bug tracker 17076 that are known to be fixed in the 3.3.2 release. This list might not be 17077 complete (that is, it is possible that some PRs that have been fixed 17078 are not listed here). 17079 17080 Bootstrap failures and problems 17081 17082 * [335]8336 [SCO5] bootstrap config still tries to use COFF options 17083 * [336]9330 [alpha-osf] Bootstrap failure on Compaq Tru64 with 17084 --enable-threads=posix 17085 * [337]9631 [hppa64-linux] gcc-3.3 fails to bootstrap 17086 * [338]9877 fixincludes makes a bad sys/byteorder.h on svr5 (UnixWare 17087 7.1.1) 17088 * [339]11687 xstormy16-elf build fails in libf2c 17089 * [340]12263 [SGI IRIX] bootstrap fails during compile of 17090 libf2c/libI77/backspace.c 17091 * [341]12490 buffer overflow in scan-decls.c (during Solaris 9 17092 fix-header processing) 17093 17094 Internal compiler errors (multi-platform) 17095 17096 * [342]7277 Casting integers to vector types causes ICE 17097 * [343]7939 (c++) ICE on invalid function template specialization 17098 * [344]11063 (c++) ICE on parsing initialization list of const array 17099 member 17100 * [345]11207 ICE with negative index in array element designator 17101 * [346]11522 (fortran) g77 dwarf-2 ICE in 17102 add_abstract_origin_attribute 17103 * [347]11595 (c++) ICE on duplicate label definition 17104 * [348]11646 (c++) ICE in commit_one_edge_insertion with 17105 -fnon-call-exceptions -fgcse -O 17106 * [349]11665 ICE in struct initializer when taking address 17107 * [350]11852 (c++) ICE with bad struct initializer. 17108 * [351]11878 (c++) ICE in cp_expr_size 17109 * [352]11883 ICE with any -O on mercury-generated C code 17110 * [353]11991 (c++) ICE in cxx_incomplete_type_diagnostic, in 17111 cp/typeck2.c when applying typeid operator to template template 17112 parameter 17113 * [354]12146 ICE in lookup_template_function, in cp/pt.c 17114 * [355]12215 ICE in make_label_edge with -fnon-call-exceptions 17115 -fno-gcse -O2 17116 * [356]12369 (c++) ICE with templates and friends 17117 * [357]12446 ICE in emit_move_insn on complicated array reference 17118 * [358]12510 ICE in final_scan_insn 17119 * [359]12544 ICE with large parameters used in nested functions 17120 17121 C and optimization bugs 17122 17123 * [360]9862 spurious warnings with -W -finline-functions 17124 * [361]10962 lookup_field is a linear search on a linked list (can be 17125 slow if large struct) 17126 * [362]11370 -Wunreachable-code gives false complaints 17127 * [363]11637 invalid assembly with -fnon-call-exceptions 17128 * [364]11885 Problem with bitfields in packed structs 17129 * [365]12082 Inappropriate unreachable code warnings 17130 * [366]12180 Inline optimization fails for variadic function 17131 * [367]12340 loop unroller + gcse produces wrong code 17132 17133 C++ compiler and library 17134 17135 * [368]3907 nested template parameter collides with member name 17136 * [369]5293 confusing message when binding a temporary to a reference 17137 * [370]5296 [DR115] Pointers to functions and to template functions 17138 behave differently in deduction 17139 * [371]7939 ICE on function template specialization 17140 * [372]8656 Unable to assign function with __attribute__ and pointer 17141 return type to an appropriate variable 17142 * [373]10147 Confusing error message for invalid template function 17143 argument 17144 * [374]11400 std::search_n() makes assumptions about Size parameter 17145 * [375]11409 issues with using declarations, overloading, and 17146 built-in functions 17147 * [376]11740 ctype<wchar_t>::do_is(mask, wchar_t) doesn't handle 17148 multiple bits in mask 17149 * [377]11786 operator() call on variable in other namespace not 17150 recognized 17151 * [378]11867 static_cast ignores ambiguity 17152 * [379]11928 bug with conversion operators that are typedefs 17153 * [380]12114 Uninitialized memory accessed in dtor 17154 * [381]12163 static_cast + explicit constructor regression 17155 * [382]12181 Wrong code with comma operator and c++ 17156 * [383]12236 regparm and fastcall messes up parameters 17157 * [384]12266 incorrect instantiation of unneeded template during 17158 overload resolution 17159 * [385]12296 istream::peek() doesn't set eofbit 17160 * [386]12298 [sjlj exceptions] Stack unwind destroys 17161 not-yet-constructed object 17162 * [387]12369 ICE with templates and friends 17163 * [388]12337 apparently infinite loop in g++ 17164 * [389]12344 stdcall attribute ignored if function returns a pointer 17165 * [390]12451 missing(late) class forward declaration in cxxabi.h 17166 * [391]12486 g++ accepts invalid use of a qualified name 17167 17168 x86 specific (Intel/AMD) 17169 17170 * [392]8869 [x86 MMX] ICE with const variable optimization and MMX 17171 builtins 17172 * [393]9786 ICE in fixup_abnormal_edges with -fnon-call-exceptions 17173 -O2 17174 * [394]11689 g++3.3 emits un-assembleable code for k6 architecture 17175 * [395]12116 [k6] Invalid assembly output values with X-MAME code 17176 * [396]12070 ICE converting between double and long double with 17177 -msoft-float 17178 17179 ia64-specific 17180 17181 * [397]11184 [ia64 hpux] ICE on __builtin_apply building libobjc 17182 * [398]11535 __builtin_return_address may not work on ia64 17183 * [399]11693 [ia64] ICE in gen_nop_type 17184 * [400]12224 [ia64] Thread-local storage doesn't work 17185 17186 PowerPC-specific 17187 17188 * [401]11087 [powerpc64-linux] GCC miscompiles raid1.c from linux 17189 kernel 17190 * [402]11319 loop miscompiled on ppc32 17191 * [403]11949 ICE Compiler segfault with ffmpeg -maltivec code 17192 17193 SPARC-specific 17194 17195 * [404]11662 wrong code for expr. with cast to long long and 17196 exclusive or 17197 * [405]11965 invalid assembler code for a shift < 32 operation 17198 * [406]12301 (c++) stack corruption when a returned expression throws 17199 an exception 17200 17201 Alpha-specific 17202 17203 * [407]11717 [alpha-linux] unrecognizable insn compiling for.c of 17204 kernel 2.4.22-pre8 17205 17206 HPUX-specific 17207 17208 * [408]11313 problem with #pragma weak and static inline functions 17209 * [409]11712 __STDC_EXT__ not defined for C++ by default anymore? 17210 17211 Solaris specific 17212 17213 * [410]12166 Profiled programs crash if PROFDIR is set 17214 17215 Solaris-x86 specific 17216 17217 * [411]12101 i386 Solaris no longer works with GNU as? 17218 17219 Miscellaneous embedded target-specific bugs 17220 17221 * [412]10988 [m32r-elf] wrong blockmove code with -O3 17222 * [413]11805 [h8300-unknown-coff] [H8300] ICE for simple code with 17223 -O2 17224 * [414]11902 [sh4] spec file improperly inserts rpath even when none 17225 needed 17226 * [415]11903 [sh4] -pthread fails to link due to error in spec file 17227 on sh4 17228 __________________________________________________________________ 17229 17230 GCC 3.3.3 17231 17232 Minor features 17233 17234 In addition to the bug fixes documented below, this release contains 17235 few minor features such as: 17236 * Support for --with-sysroot 17237 * Support for automatic detection of executable stacks 17238 * Support for SSE3 instructions 17239 * Support for thread local storage debugging under GDB on S390 17240 17241 Bug Fixes 17242 17243 This section lists the problem reports (PRs) from GCC's bug tracker 17244 that are known to be fixed in the 3.3.3 release. This list might not be 17245 complete (that is, it is possible that some PRs that have been fixed 17246 are not listed here). 17247 17248 Bootstrap failures and issues 17249 17250 * [416]11890 Building cross gcc-3.3.1 for sparc-sun-solaris2.6 fails 17251 * [417]12399 boehm-gc fails (when building a cross compiler): libtool 17252 unable to infer tagged configuration 17253 * [418]13068 mklibgcc.in doesn't handle multi-level multilib 17254 subdirectories properly 17255 17256 Internal compiler errors (multi-platform) 17257 17258 * [419]10060 ICE (stack overflow) on huge file (300k lines) due to 17259 recursive behaviour of copy_rtx_if_shared, in emit_rtl.c 17260 * [420]10555 (c++) ICE on undefined template argument 17261 * [421]10706 (c++) ICE in mangle_class_name_for_template 17262 * [422]11496 (fortran) error in flow_loops_find when -funroll-loops 17263 active 17264 * [423]11741 ICE in pre_insert_copy_insn, in gcse.c 17265 * [424]12440 GCC crashes during compilation of quicktime4linux 2.0.0 17266 * [425]12632 (fortran) -fbounds-check ICE 17267 * [426]12712 (c++) ICE on short legit C++ code fragment with gcc 17268 3.3.2 17269 * [427]12726 (c++) ICE (segfault) on trivial code 17270 * [428]12890 (c++) ICE on compilation of class with throwing method 17271 * [429]12900 (c++) ICE in rtl_verify_flow_info_1 17272 * [430]13060 (fortran) ICE in fixup_var_refs_1, in function.c on 17273 correct code with -O2 -fno-force-mem 17274 * [431]13289 (c++) ICE in regenerate_decl_from_template on recursive 17275 template 17276 * [432]13318 ICE: floating point exception in the loop optimizer 17277 * [433]13392 (c++) ICE in convert_from_eh_region_ranges_1, in 17278 except.c 17279 * [434]13574 (c++) invalid array default initializer in class lets 17280 gcc consume all memory and die 17281 * [435]13475 ICE on SIMD variables with partial value initialization 17282 * [436]13797 (c++) ICE on invalid template parameter 17283 * [437]13824 (java) gcj SEGV with simple .java program 17284 17285 C and optimization bugs 17286 17287 * [438]8776 loop invariants are not removed (most likely) 17288 * [439]10339 [sparc,ppc,ppc64] Invalid optimization: replacing 17289 strncmp by memcmp 17290 * [440]11350 undefined labels with -Os -fPIC 17291 * [441]12826 Optimizer removes reference through volatile pointer 17292 * [442]12500 stabs debug info: void no longer a predefined / builtin 17293 type 17294 * [443]12941 builtin-bitops-1.c miscompilation (latent bug) 17295 * [444]12953 tree inliner bug (in inline_forbidden_p) and fix 17296 * [445]13041 linux-2.6/sound/core/oss/rate.c miscompiled 17297 * [446]13507 spurious printf format warning 17298 * [447]13382 Type information for const pointer disappears during 17299 optimization. 17300 * [448]13394 noreturn attribute ignored on recursive invokation 17301 * [449]13400 Compiled code crashes storing to read-only location 17302 * [450]13521 Endless loop in calculate_global_regs_live 17303 17304 C++ compiler and library 17305 17306 Some of the bug fixes in this list were made to implement decisions 17307 that the ISO C++ standards committee has made concerning several defect 17308 reports (DRs). Links in the list below point to detailed discussion of 17309 the relevant defect report. 17310 * [451]2094 unimplemented: use of `ptrmem_cst' in template type 17311 unification 17312 * [452]2294 using declaration confusion 17313 * [453]5050 template instantiation depth exceeds limit: recursion 17314 problem? 17315 * [454]9371 Bad exception handling in 17316 i/ostream::operator>>/<<(streambuf*) 17317 * [455]9546 bad exception handling in ostream members 17318 * [456]10081 basic_ios::_M_cache_locale leaves NULL members in the 17319 face of unknown locales 17320 * [457]10093 [458][DR 61] Setting failbit in exceptions doesn't work 17321 * [459]10095 istream::operator>>(int&) sets ios::badbit when 17322 ios::failbit is set. 17323 * [460]11554 Warning about reordering of initializers doesn't mention 17324 location of constructor 17325 * [461]12297 istream::sentry::sentry() handles eof() incorrectly. 17326 * [462]12352 Exception safety problems in src/localename.cc 17327 * [463]12438 Memory leak in locale::combine() 17328 * [464]12540 Memory leak in locale::locale(const char*) 17329 * [465]12594 DRs [466]60 [TC] and [467]63 [TC] not implemented 17330 * [468]12657 Resolution of [469]DR 292 (WP) still unimplemented 17331 * [470]12696 memory eating infinite loop in diagnostics (error 17332 recovery problem) 17333 * [471]12815 Code compiled with optimization behaves unexpectedly 17334 * [472]12862 Conflicts between typedefs/enums and namespace member 17335 declarations 17336 * [473]12926 Wrong value after assignment in initialize list using 17337 bit-fields 17338 * [474]12967 Resolution of [475]DR 300 [WP] still unimplemented 17339 * [476]12971 Resolution of [477]DR 328 [WP] still unimplemented 17340 * [478]13007 basic_streambuf::pubimbue, imbue wrong 17341 * [479]13009 Implicitly-defined assignment operator writes to wrong 17342 memory 17343 * [480]13057 regparm attribute not applied to destructor 17344 * [481]13070 -Wformat option ignored in g++ 17345 * [482]13081 forward template declarations in <complex> let inlining 17346 fail 17347 * [483]13239 Assertion does not seem to work correctly anymore 17348 * [484]13262 "xxx is private within this context" when initializing a 17349 self-contained template class 17350 * [485]13290 simple typo in concept checking for std::generate_n 17351 * [486]13323 Template code does not compile in presence of typedef 17352 * [487]13369 __verify_grouping (and __add_grouping?) not correct 17353 * [488]13371 infinite loop with packed struct and inlining 17354 * [489]13445 Template argument replacement "dereferences" a typedef 17355 * [490]13461 Fails to access protected-ctor from public constant 17356 * [491]13462 Non-standard-conforming type set::pointer 17357 * [492]13478 gcc uses wrong constructor to initialize a const 17358 reference 17359 * [493]13544 "conflicting types" for enums in different scopes 17360 * [494]13650 string::compare should not (always) use 17361 traits_type::length() 17362 * [495]13683 bogus warning about passing non-PODs through ellipsis 17363 * [496]13688 Derived class is denied access to protected base class 17364 member class 17365 * [497]13774 Member variable cleared in virtual multiple inheritance 17366 class 17367 * [498]13884 Protect sstream.tcc from extern template use 17368 17369 Java compiler and library 17370 17371 * [499]10746 [win32] garbage collection crash in GCJ 17372 17373 Objective-C compiler and library 17374 17375 * [500]11433 Crash due to dereferencing null pointer when querying 17376 protocol 17377 17378 Fortran compiler and library 17379 17380 * [501]12633 logical expression gives incorrect result with 17381 -fugly-logint option 17382 * [502]13037 [gcse-lm] g77 generates incorrect code 17383 * [503]13213 Hex constant problem when compiling with -fugly-logint 17384 and -ftypeless-boz 17385 17386 x86-specific (Intel/AMD) 17387 17388 * [504]4490 ICE with -m128bit-long-double 17389 * [505]12292 [x86_64] ICE: RTL check: expected code `const_int', have 17390 `reg' in make_field_assignment, in combine.c 17391 * [506]12441 ICE: can't find a register to spill 17392 * [507]12943 array static-init failure under -fpic, -fPIC 17393 * [508]13608 Incorrect code with -O3 -ffast-math 17394 17395 PowerPC-specific 17396 17397 * [509]11598 testcase gcc.dg/20020118-1.c fails runtime check of 17398 __attribute__((aligned(16))) 17399 * [510]11793 ICE in extract_insn, in recog.c (const_vector's) 17400 * [511]12467 vmsumubm emitted when vmsummbm appropriate (typo in 17401 altivec.md) 17402 * [512]12537 g++ generates writeable text sections 17403 17404 SPARC-specific 17405 17406 * [513]12496 wrong result for __atomic_add(&value, -1) when using -O0 17407 -m64 17408 * [514]12865 mprotect call to make trampoline executable may fail 17409 * [515]13354 ICE in sparc_emit_set_const32 17410 17411 ARM-specific 17412 17413 * [516]10467 [arm] ICE in pre_insert_copy_insn, 17414 17415 ia64-specific 17416 17417 * [517]11226 ICE passing struct arg with two floats 17418 * [518]11227 ICE for _Complex float, _Complex long double args 17419 * [519]12644 GCC 3.3.2 fails to compile glibc on ia64 17420 * [520]13149 build gcc-3.3.2 1305 error:unrecognizable insn 17421 * Various fixes for libunwind 17422 17423 Alpha-specific 17424 17425 * [521]12654 Incorrect comparison code generated for Alpha 17426 * [522]12965 SEGV+ICE in cc1plus on alpha-linux with -O2 17427 * [523]13031 ICE (unrecognizable insn) when building gnome-libs-1.4.2 17428 17429 HPPA-specific 17430 17431 * [524]11634 [hppa] ICE in verify_local_live_at_start, in flow.c 17432 * [525]12158 [hppa] compilation does not terminate at -O1 17433 17434 S390-specific 17435 17436 * [526]11992 Wrong built-in code for memcmp with length 1<<24: only 17437 (1<<24)-1 possible for CLCL-Instruction 17438 17439 SH-specific 17440 17441 * [527]9365 segfault in gen_far_branch (config/sh/sh.c) 17442 * [528]10392 optimizer generates faulty array indexing 17443 * [529]11322 SH profiler outputs multiple definitions of symbol 17444 * [530]13069 gcc/config/sh/rtems.h broken 17445 * [531]13302 Putting a va_list in a struct causes seg fault 17446 * [532]13585 Incorrect optimization of call to sfunc 17447 * Fix inappropriately exported libgcc functions from the shared 17448 library 17449 17450 Other embedded target specific 17451 17452 * [533]8916 [mcore] unsigned char assign gets hosed. 17453 * [534]11576 [h8300] ICE in change_address_1, in emit-rtl.c 17454 * [535]13122 [h8300] local variable gets corrupted by function call 17455 when -fomit-frame-pointer is given 17456 * [536]13256 [cris] strict_low_part mistreated in delay slots 17457 * [537]13373 [mcore] optimization with -frerun-cse-after-loop 17458 -fexpensive-optimizations produces wrong code on mcore 17459 17460 GNU HURD-specific 17461 17462 * [538]12561 gcc/config/t-gnu needs updating to work with 17463 --with-sysroot 17464 17465 Tru64 Unix specific 17466 17467 * [539]6243 testsuite fails almost all tests due to no libintl in 17468 LD_LIBRARY_PATH during test. 17469 * [540]11397 weak aliases broken on Tru64 UNIX 17470 17471 AIX-specific 17472 17473 * [541]12505 build failure due to defines of uchar in cpphash.h and 17474 sys/types.h 17475 * [542]13150 WEAK symbols not exported by collect2 17476 17477 IRIX-specific 17478 17479 * [543]12666 fixincludes problem on IRIX 6.5.19m 17480 17481 Solaris-specific 17482 17483 * [544]12969 Including sys/byteorder.h breaks configure checks 17484 17485 Testsuite problems (compiler is not affected) 17486 17487 * [545]10819 testsuite creates CR+LF on compiler version lines in 17488 test summary files 17489 * [546]11612 abi_check not finding correct libgcc_s.so.1 17490 17491 Miscellaneous 17492 17493 * [547]13211 using -###, incorrect warnings about unused linker file 17494 are produced 17495 __________________________________________________________________ 17496 17497 GCC 3.3.4 17498 17499 This is the [548]list of problem reports (PRs) from GCC's bug tracking 17500 system that are known to be fixed in the 3.3.4 release. This list might 17501 not be complete (that is, it is possible that some PRs that have been 17502 fixed are not listed here). 17503 __________________________________________________________________ 17504 17505 GCC 3.3.5 17506 17507 This is the [549]list of problem reports (PRs) from GCC's bug tracking 17508 system that are known to be fixed in the 3.3.5 release. This list might 17509 not be complete (that is, it is possible that some PRs that have been 17510 fixed are not listed here). 17511 __________________________________________________________________ 17512 17513 GCC 3.3.6 17514 17515 This is the [550]list of problem reports (PRs) from GCC's bug tracking 17516 system that are known to be fixed in the 3.3.6 release. This list might 17517 not be complete (that is, it is possible that some PRs that have been 17518 fixed are not listed here). 17519 17520 17521 For questions related to the use of GCC, please consult these web 17522 pages and the [551]GCC manuals. If that fails, the 17523 [552]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 17524 web pages and the development of GCC are welcome on our developer 17525 list at [553]gcc (a] gcc.gnu.org. All of [554]our lists have public 17526 archives. 17527 17528 Copyright (C) [555]Free Software Foundation, Inc. Verbatim copying and 17529 distribution of this entire article is permitted in any medium, 17530 provided this notice is preserved. 17531 17532 These pages are [556]maintained by the GCC team. Last modified 17533 2021-07-28[557]. 17534 17535 References 17536 17537 1. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 17538 2. http://gcc.gnu.org/gcc-3.1/changes.html#obsolete_systems 17539 3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems 17540 4. http://gcc.gnu.org/gcc-3.3/changes.html#nonnull_attribute 17541 5. http://gcc.gnu.org/news/dfa.html 17542 6. http://gcc.gnu.org/c99status.html 17543 7. https://gcc.gnu.org/onlinedocs/gcc-3.3.6/g77/News.html 17544 8. https://gcc.gnu.org/PR10140 17545 9. https://gcc.gnu.org/PR10198 17546 10. https://gcc.gnu.org/PR10338 17547 11. https://gcc.gnu.org/PR3581 17548 12. https://gcc.gnu.org/PR4382 17549 13. https://gcc.gnu.org/PR5533 17550 14. https://gcc.gnu.org/PR6387 17551 15. https://gcc.gnu.org/PR6412 17552 16. https://gcc.gnu.org/PR6620 17553 17. https://gcc.gnu.org/PR6663 17554 18. https://gcc.gnu.org/PR7068 17555 19. https://gcc.gnu.org/PR7083 17556 20. https://gcc.gnu.org/PR7647 17557 21. https://gcc.gnu.org/PR7675 17558 22. 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232. https://gcc.gnu.org/PR11282 17769 233. https://gcc.gnu.org/PR11301 17770 234. https://gcc.gnu.org/PR11308 17771 235. https://gcc.gnu.org/PR11473 17772 236. https://gcc.gnu.org/PR11503 17773 237. https://gcc.gnu.org/PR11513 17774 238. https://gcc.gnu.org/PR11198 17775 239. https://gcc.gnu.org/PR11304 17776 240. https://gcc.gnu.org/PR11381 17777 241. https://gcc.gnu.org/PR11536 17778 242. https://gcc.gnu.org/PR11557 17779 243. https://gcc.gnu.org/PR5897 17780 244. https://gcc.gnu.org/PR11279 17781 245. https://gcc.gnu.org/PR11022 17782 246. https://gcc.gnu.org/PR2330 17783 247. https://gcc.gnu.org/PR5388 17784 248. https://gcc.gnu.org/PR5390 17785 249. https://gcc.gnu.org/PR7877 17786 250. https://gcc.gnu.org/PR9393 17787 251. https://gcc.gnu.org/PR10032 17788 252. https://gcc.gnu.org/PR10468 17789 253. https://gcc.gnu.org/PR10527 17790 254. https://gcc.gnu.org/PR10679 17791 255. https://gcc.gnu.org/PR10682 17792 256. https://gcc.gnu.org/PR10689 17793 257. 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https://gcc.gnu.org/PR12441 18043 507. https://gcc.gnu.org/PR12943 18044 508. https://gcc.gnu.org/PR13608 18045 509. https://gcc.gnu.org/PR11598 18046 510. https://gcc.gnu.org/PR11793 18047 511. https://gcc.gnu.org/PR12467 18048 512. https://gcc.gnu.org/PR12537 18049 513. https://gcc.gnu.org/PR12496 18050 514. https://gcc.gnu.org/PR12865 18051 515. https://gcc.gnu.org/PR13354 18052 516. https://gcc.gnu.org/PR10467 18053 517. https://gcc.gnu.org/PR11226 18054 518. https://gcc.gnu.org/PR11227 18055 519. https://gcc.gnu.org/PR12644 18056 520. https://gcc.gnu.org/PR13149 18057 521. https://gcc.gnu.org/PR12654 18058 522. https://gcc.gnu.org/PR12965 18059 523. https://gcc.gnu.org/PR13031 18060 524. https://gcc.gnu.org/PR11634 18061 525. https://gcc.gnu.org/PR12158 18062 526. https://gcc.gnu.org/PR11992 18063 527. https://gcc.gnu.org/PR9365 18064 528. https://gcc.gnu.org/PR10392 18065 529. https://gcc.gnu.org/PR11322 18066 530. https://gcc.gnu.org/PR13069 18067 531. https://gcc.gnu.org/PR13302 18068 532. https://gcc.gnu.org/PR13585 18069 533. https://gcc.gnu.org/PR8916 18070 534. https://gcc.gnu.org/PR11576 18071 535. https://gcc.gnu.org/PR13122 18072 536. https://gcc.gnu.org/PR13256 18073 537. https://gcc.gnu.org/PR13373 18074 538. https://gcc.gnu.org/PR12561 18075 539. https://gcc.gnu.org/PR6243 18076 540. https://gcc.gnu.org/PR11397 18077 541. https://gcc.gnu.org/PR12505 18078 542. https://gcc.gnu.org/PR13150 18079 543. https://gcc.gnu.org/PR12666 18080 544. https://gcc.gnu.org/PR12969 18081 545. https://gcc.gnu.org/PR10819 18082 546. https://gcc.gnu.org/PR11612 18083 547. https://gcc.gnu.org/PR13211 18084 548. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.4 18085 549. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.5 18086 550. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.6 18087 551. https://gcc.gnu.org/onlinedocs/ 18088 552. mailto:gcc-help (a] gcc.gnu.org 18089 553. mailto:gcc (a] gcc.gnu.org 18090 554. https://gcc.gnu.org/lists.html 18091 555. https://www.fsf.org/ 18092 556. https://gcc.gnu.org/about.html 18093 557. http://validator.w3.org/check/referer 18094 ====================================================================== 18095 http://gcc.gnu.org/gcc-3.2/index.html 18096 GCC 3.2 Release Series 18097 18098 (This release series is no longer supported.) 18099 18100 April 25, 2003 18101 18102 The [1]GNU project and the GCC developers are pleased to announce the 18103 release of GCC 3.2.3. 18104 18105 The purpose of the GCC 3.2 release series is to provide a stable 18106 platform for OS distributors to use building their next releases. A 18107 primary objective was to stabilize the C++ ABI; we believe that the 18108 interface to the compiler and the C++ standard library are now 18109 relatively stable. 18110 18111 Be aware that C++ code compiled by GCC 3.2.x will (in general) not 18112 interoperate with code compiled by GCC 3.1.1 or earlier. 18113 18114 Please refer to our [2]detailed list of news, caveats, and bug-fixes 18115 for further information. 18116 18117 Release History 18118 18119 GCC 3.2.3 18120 April 25, 2003 ([3]changes) 18121 18122 GCC 3.2.2 18123 February 5, 2003 ([4]changes) 18124 18125 GCC 3.2.1 18126 November 19, 2002 ([5]changes) 18127 18128 GCC 3.2 18129 August 14, 2002 ([6]changes) 18130 18131 References and Acknowledgements 18132 18133 GCC used to stand for the GNU C Compiler, but since the compiler 18134 supports several other languages aside from C, it now stands for the 18135 GNU Compiler Collection. 18136 18137 A list of [7]successful builds is updated as new information becomes 18138 available. 18139 18140 The GCC developers would like to thank the numerous people that have 18141 contributed new features, improvements, bug fixes, and other changes as 18142 well as test results to GCC. This [8]amazing group of volunteers is 18143 what makes GCC successful. 18144 18145 For additional information about GCC please refer to the [9]GCC project 18146 web site or contact the [10]GCC development mailing list. 18147 18148 To obtain GCC please use [11]our mirror sites, or our CVS server. 18149 18150 18151 For questions related to the use of GCC, please consult these web 18152 pages and the [12]GCC manuals. If that fails, the 18153 [13]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 18154 web pages and the development of GCC are welcome on our developer 18155 list at [14]gcc (a] gcc.gnu.org. All of [15]our lists have public 18156 archives. 18157 18158 Copyright (C) [16]Free Software Foundation, Inc. Verbatim copying and 18159 distribution of this entire article is permitted in any medium, 18160 provided this notice is preserved. 18161 18162 These pages are [17]maintained by the GCC team. Last modified 18163 2021-07-28[18]. 18164 18165 References 18166 18167 1. http://www.gnu.org/ 18168 2. http://gcc.gnu.org/gcc-3.2/changes.html 18169 3. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 18170 4. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.2 18171 5. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.1 18172 6. http://gcc.gnu.org/gcc-3.2/changes.html#3.2 18173 7. http://gcc.gnu.org/gcc-3.2/buildstat.html 18174 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 18175 9. http://gcc.gnu.org/index.html 18176 10. mailto:gcc (a] gcc.gnu.org 18177 11. http://gcc.gnu.org/mirrors.html 18178 12. https://gcc.gnu.org/onlinedocs/ 18179 13. mailto:gcc-help (a] gcc.gnu.org 18180 14. mailto:gcc (a] gcc.gnu.org 18181 15. https://gcc.gnu.org/lists.html 18182 16. https://www.fsf.org/ 18183 17. https://gcc.gnu.org/about.html 18184 18. http://validator.w3.org/check/referer 18185 ====================================================================== 18186 http://gcc.gnu.org/gcc-3.2/changes.html 18187 GCC 3.2 Release Series 18188 Changes, New Features, and Fixes 18189 18190 The latest release in the 3.2 release series is [1]GCC 3.2.3. 18191 18192 Caveats and New Features 18193 18194 Caveats 18195 18196 * The C++ compiler does not correctly zero-initialize 18197 pointers-to-data members. You must explicitly initialize them. For 18198 example: int S::*m(0); will work, but depending on 18199 default-initialization to zero will not work. This bug cannot be 18200 fixed in GCC 3.2 without inducing unacceptable risks. It will be 18201 fixed in GCC 3.3. 18202 * This GCC release is based on the GCC 3.1 sourcebase, and thus has 18203 all the [2]changes in the GCC 3.1 series. In addition, GCC 3.2 has 18204 a number of C++ ABI fixes which make its C++ compiler generate 18205 binary code which is incompatible with the C++ compilers found in 18206 earlier GCC releases, including GCC 3.1 and GCC 3.1.1. 18207 18208 Frontend Enhancements 18209 18210 C/C++/Objective-C 18211 18212 * The method of constructing the list of directories to be searched 18213 for header files has been revised. If a directory named by a -I 18214 option is a standard system include directory, the option is 18215 ignored to ensure that the default search order for system 18216 directories and the special treatment of system header files are 18217 not defeated. 18218 * The C and Objective-C compilers no longer accept the "Naming Types" 18219 extension (typedef foo = bar); it was already unavailable in C++. 18220 Code which uses it will need to be changed to use the "typeof" 18221 extension instead: typedef typeof(bar) foo. (We have removed this 18222 extension without a period of deprecation because it has caused the 18223 compiler to crash since version 3.0 and no one noticed until very 18224 recently. Thus we conclude it is not in widespread use.) 18225 18226 C++ 18227 18228 * GCC 3.2 fixed serveral differences between the C++ ABI implemented 18229 in GCC and the multi-vendor standard, but more have been found 18230 since the release. 3.2.1 adds a new warning, -Wabi, to warn about 18231 code which is affected by these bugs. We will fix these bugs in 18232 some future release, once we are confident that all have been 18233 found; until then, it is our intention to make changes to the ABI 18234 only if they are necessary for correct compilation of C++, as 18235 opposed to conformance to the ABI documents. 18236 * For details on how to build an ABI compliant compiler for GNU/Linux 18237 systems, check the [3]common C++ ABI page. 18238 18239 New Targets and Target Specific Improvements 18240 18241 IA-32 18242 18243 * Fixed a number of bugs in SSE and MMX intrinsics. 18244 * Fixed common compiler crashes with SSE instruction set enabled 18245 (implied by -march=pentium3, pentium4, athlon-xp) 18246 * __m128 and __m128i is not 128bit aligned when used in structures. 18247 18248 x86-64 18249 18250 * A bug whereby the compiler could generate bad code for bzero has 18251 been fixed. 18252 * ABI fixes (implying ABI incompatibilities with previous version in 18253 some corner cases) 18254 * Fixed prefetch code generation 18255 __________________________________________________________________ 18256 18257 GCC 3.2.3 18258 18259 3.2.3 is a bug fix release only; there are no new features that were 18260 not present in GCC 3.2.2. 18261 18262 Bug Fixes 18263 18264 This section lists the problem reports (PRs) from GCC's bug tracking 18265 system that are known to be fixed in the 3.2.3 release. This list might 18266 not be complete (that is, it is possible that some PRs that have been 18267 fixed are not listed here), and some of the titles have been changed to 18268 make them more clear. 18269 18270 Internal Compiler Errors (multi-platform) 18271 18272 * [4]3782: (c++) -quiet -fstats produces a segmentation fault in 18273 cc1plus 18274 * [5]6440: (c++) template specializations cause ICE 18275 * [6]7050: (c++) ICE on: (i ? get_string() : throw) 18276 * [7]7741: ICE on conflicting types (make_decl_rtl in varasm.c) 18277 * [8]7982: (c++) ICE due to infinite recursion (using STL set) 18278 * [9]8068: exceedingly high (infinite) memory usage 18279 * [10]8178: ICE with __builtin_ffs 18280 * [11]8396: ICE in copy_to_mode_reg, in explow.c 18281 * [12]8674: (c++) ICE in cp_expr_size, in cp/cp-lang.c 18282 * [13]9768: ICE when optimizing inline code at -O2 18283 * [14]9798: (c++) Infinite recursion (segfault) in 18284 cp/decl.c:push_using_directive with recursive using directives 18285 * [15]9799: mismatching structure initializer with nested flexible 18286 array member: ICE 18287 * [16]9928: ICE on duplicate enum declaration 18288 * [17]10114: ICE in mem_loc_descriptor, in dwarf2out.c (affects 18289 sparc, alpha) 18290 * [18]10352: ICE in find_reloads_toplev 18291 * [19]10336: ICE with -Wunreachable-code 18292 18293 C/optimizer bugs: 18294 18295 * [20]8224: Incorrect joining of signed and unsigned division 18296 * [21]8613: -O2 produces wrong code with builtin strlen and 18297 postincrements 18298 * [22]8828: gcc reports some code is unreachable when it is not 18299 * [23]9226: GCSE breaking argument passing 18300 * [24]9853: miscompilation of non-constant structure initializer 18301 * [25]9797: C99-style struct initializers are miscompiled 18302 * [26]9967: Some standard C function calls should not be replaced 18303 when optimizing for size 18304 * [27]10116: ce2: invalid merge of join_bb in the context of switch 18305 statements 18306 * [28]10171: wrong code for inlined function 18307 * [29]10175: -Wunreachable-code doesn't work for single lines 18308 18309 C++ compiler and library: 18310 18311 * [30]8316: Confusing diagnostic for code that misuses conversion 18312 operators 18313 * [31]9169: filebuf output fails if codecvt<>::out returns noconv 18314 * [32]9420: incomplete type incorrectly reported 18315 * [33]9459: typeof in return type specification of template not 18316 supported 18317 * [34]9507: filebuf::open handles ios_base::ate incorrectly 18318 * [35]9538: Out-of-bounds memory access in streambuf::sputbackc 18319 * [36]9602: Total confusion about template/friend/virtual/abstract 18320 * [37]9993: destructor not called for local object created within and 18321 returned from infinite loop 18322 * [38]10167: ieee_1003.1-2001 locale specialisations on a glibc-2.3.2 18323 system 18324 18325 Java compiler and library: 18326 18327 * [39]9652: libgcj build fails on irix6.5.1[78] 18328 * [40]10144: gas on solaris complains about bad .stabs lines for 18329 java, native as unaffected 18330 18331 x86-specific (Intel/AMD): 18332 18333 * [41]8746: gcc miscompiles Linux kernel ppa driver on x86 18334 * [42]9888: -mcpu=k6 -Os produces out of range loop instructions 18335 * [43]9638: Cross-build for target i386-elf and i586-pc-linux-gnu 18336 failed 18337 * [44]9954: Cross-build for target i586-pc-linux-gnu (--with-newlib) 18338 failed 18339 18340 SPARC-specific: 18341 18342 * [45]7784: [Sparc] ICE in extract_insn, in recog.c 18343 * [46]7796: sparc extra failure with -m64 on execute/930921-1.c in 18344 unroll.c 18345 * [47]8281: ICE when compiling with -O2 -fPIC for Ultrasparc 18346 * [48]8366: [Sparc] C testsuite failure with -m64 -fpic -O in 18347 execute/loop-2d.c 18348 * [49]8726: gcc -O2 miscompiles Samba 2.2.7 on 32-bit sparc 18349 * [50]9414: Scheduling bug on Ultrasparc 18350 * [51]10067: GCC-3.2.2 outputs invalid asm on sparc64 18351 18352 m68k-specific: 18353 18354 * [52]7248: broken "inclusive or" code 18355 * [53]8343: m68k-elf/rtems ICE at instantiate_virtual_regs_1 18356 18357 PowerPC-specific: 18358 18359 * [54]9732: Wrong code with -O2 -fPIC 18360 * [55]10073: ICE: powerpc cannot split insn 18361 18362 Alpha-specific: 18363 18364 * [56]7702: optimization problem on a DEC alpha under OSF1 18365 * [57]9671: gcc.3.2.2 does not build on a HP Tru64 Unix v5.1B system 18366 18367 HP-specific: 18368 18369 * [58]8694: <string> breaks <ctype.h> on HP-UX 10.20 (DUP: 9275) 18370 * [59]9953: (ada) gcc 3.2.x can't build 3.3-branch ada on HP-UX 10 18371 (missing symbol) 18372 * [60]10271: Floating point args don't get reloaded across function 18373 calls with -O2 18374 18375 MIPS specific: 18376 18377 * [61]6362: mips-irix6 gcc-3.1 C testsuite failure with -mips4 in 18378 compile/920501-4.c 18379 18380 CRIS specific: 18381 18382 * [62]10377: gcc-3.2.2 creates bad assembler code for cris 18383 18384 Miscellaneous and minor bugs: 18385 18386 * [63]6955: collect2 says "core dumped" when there is no core 18387 __________________________________________________________________ 18388 18389 GCC 3.2.2 18390 18391 Beginning with 3.2.2, GCC's Makefile suite supports redirection of make 18392 install by means of the DESTDIR variable. Parts of the GCC tree have 18393 featured that support long before, but now it is available even from 18394 the top level. 18395 18396 Other than that, GCC 3.2.2 is a bug fix release only; there are no new 18397 features that were not present in GCC 3.2.1. 18398 18399 Bug Fixes 18400 18401 On the following i386-based systems GCC 3.2.1 broke the C ABI wrt. 18402 functions returning structures: Cygwin, FreeBSD (GCC 3.2.1 as shipped 18403 with FreeBSD 5.0 does not have this problem), Interix, a.out-based 18404 GNU/Linux and NetBSD, OpenBSD, and Darwin. GCC 3.2.2 reverts this ABI 18405 change, and thus restores ABI-compatibility with previous releases 18406 (except GCC 3.2.1) on these platforms. 18407 18408 This section lists the problem reports (PRs) from GCC's bug tracking 18409 system that are known to be fixed in the 3.2.2 release. This list might 18410 not be complete (that is, it is possible that some PRs that have been 18411 fixed are not listed here) and some of the titles have been changed to 18412 make them more clear. 18413 18414 Internal Compiler Errors (multi-platform) 18415 18416 * [64]5919: (c++) ICE when passing variable array to template 18417 function 18418 * [65]7129: (c++) ICE with min/max assignment operators (<?= and >?=) 18419 * [66]7507: ICE with -O2 when address of called function is a 18420 complicated expression 18421 * [67]7622: ICE with nested inline functions if function's address is 18422 taken 18423 * [68]7681: (fortran) ICE in compensate_edge, in reg-stack.c (also PR 18424 [69]9258) 18425 * [70]8031: (c++) ICE in code comparing typeids and casting from 18426 virtual base 18427 * [71]8275: ICE in simplify_subreg 18428 * [72]8332: (c++) builtin strlen/template interaction causes ICE 18429 * [73]8372: (c++) ICE on explicit call of destructor 18430 * [74]8439: (c, not c++) empty struct causes ICE 18431 * [75]8442: (c++) ICE with nested template classes 18432 * [76]8518: ICE when compiling mplayer ("extern inline" issue) 18433 * [77]8615: (c++) ICE with out-of-range character constant template 18434 argument 18435 * [78]8663: (c++) ICE in cp_expr_size, at cp-lang.c:307 18436 * [79]8799: (c++) ICE: error reporting routines re-entered 18437 * [80]9328: (c++) ICE with typeof(X) for overloaded X 18438 * [81]9465: (preprocessor) cpp -traditional ICE on null bytes 18439 18440 C++ (compiler and library) bugs 18441 18442 * [82]47: scoping in nested classes is broken 18443 * [83]6745: problems with iostream rdbuf() member function 18444 * [84]8214: conversion from const char* const to char* sometimes 18445 accepted illegally 18446 * [85]8493: builtin strlen and overload resolution (same bug as 18447 [86]8332) 18448 * [87]8503: strange behaviour of function types 18449 * [88]8727: compiler confused by inheritance from an anonymous struct 18450 * [89]7445: poor performance of std::locale::classic() in 18451 multi-threaded applications 18452 * [90]8230: mishandling of overflow in vector<T>::resize 18453 * [91]8399: sync_with_stdio(false) breaks unformatted input 18454 * [92]8662: illegal access of private member of unnamed class is 18455 accepted 18456 * [93]8707: "make distclean" fails in libstdc++-v3 directory 18457 * [94]8708: __USE_MALLOC doesn't work 18458 * [95]8790: Use of non-thread-safe strtok in src/localename.cc 18459 * [96]8887: Bug in date formats with --enable-clocale=generic 18460 * [97]9076: Call Frame Instructions are not handled correctly during 18461 unwind operation 18462 * [98]9151: std::setprecision limited to 16 digits when outputting a 18463 double to a stream 18464 * [99]9168: codecvt<char, char, mbstate_t> overwrites output buffers 18465 * [100]9269: libstdc++ headers: explicit specialization of function 18466 must precede its first use 18467 * [101]9322: return value of basic_streambuf<>::getloc affected by 18468 locale::global 18469 * [102]9433: segfault in runtime support for dynamic_cast 18470 18471 C and optimizer bugs 18472 18473 * [103]8032: GCC incorrectly initializes static structs that have 18474 flexible arrays 18475 * [104]8639: simple arithmetic expression broken 18476 * [105]8794: optimization improperly eliminates certain expressions 18477 * [106]8832: traditional "asm volatile" code is illegally optimized 18478 * [107]8988: loop optimizer bug: with -O2, code is generated that 18479 segfaults (found on i386, bug present for all platforms) 18480 * [108]9492: structure copy clobbers subsequent stores to structure 18481 18482 Objective-C bugs 18483 18484 * [109]9267: Objective-C parser won't build with newer bison versions 18485 (e.g. 1.875) 18486 18487 Ada bugs 18488 18489 * [110]8344: Ada build problem due to conflict between gcc/final.o, 18490 gcc/ada/final.o 18491 18492 Preprocessor bugs 18493 18494 * [111]8524: _Pragma within macros is improperly expanded 18495 * [112]8880: __WCHAR_TYPE__ macro incorrectly set to "long int" with 18496 -fshort-wchar 18497 18498 ARM-specific 18499 18500 * [113]9090: arm ICE with >= -O2; regression from gcc-2.95 18501 18502 x86-specific (Intel/AMD) 18503 18504 * [114]8588: ICE in extract_insn, at recog.c:NNNN (shift instruction) 18505 * [115]8599: loop unroll bug with -march=k6-3 18506 * [116]9506: ABI breakage in structure return (affects BSD and 18507 Cygwin, but not GNU/Linux) 18508 18509 FreeBSD 5.0 specific 18510 18511 * [117]9484: GCC 3.2.1 Bootstrap failure on FreeBSD 5.0 18512 18513 RTEMS-specific 18514 18515 * [118]9292: hppa1.1-rtems configurery problems 18516 * [119]9293: [m68k-elf/rtems] config/m68k/t-crtstuff bug 18517 * [120]9295: [mips-rtems] config/mips/rtems.h init/fini issue 18518 * [121]9296: gthr-rtems regression 18519 * [122]9316: powerpc-rtems: extending multilibs 18520 18521 HP-PA specific 18522 18523 * [123]9493: ICE with -O2 when building a simple function 18524 18525 Documentation 18526 18527 * [124]7341: hyperlink to gcov in GCC documentation doesn't work 18528 * [125]8947: Please add a warning about "-malign-double" in docs 18529 * [126]7448, [127]8882: typo cleanups 18530 __________________________________________________________________ 18531 18532 GCC 3.2.1 18533 18534 3.2.1 adds a new warning, -Wabi. This option warns when GNU C++ 18535 generates code that is known not to be binary-compatible with the 18536 vendor-neutral ia32/ia64 ABI. Please consult the GCC manual, included 18537 in the distribution, for details. 18538 18539 This release also removes an old GCC extension, "naming types", and the 18540 documentation now directs users to use a different GCC extension, 18541 __typeof__, instead. The feature had evidently been broken for a while. 18542 18543 Otherwise, 3.2.1 is a bug fix release only; other than bug fixes and 18544 the new warning there are no new features that were not present in GCC 18545 3.2. 18546 18547 In addition, the previous fix for [128]PR 7445 (poor performance of 18548 std::locale::classic() in multi-threaded applications) was reverted 18549 ("unfixed"), because the "fix" was not thread-safe. 18550 18551 Bug Fixes 18552 18553 This section lists the problem reports (PRs) from GCC's bug tracking 18554 system that are known to be fixed in the 3.2.1 release. This list might 18555 not be complete (that is, it is possible that some PRs that have been 18556 fixed are not listed here). As you can see, the number of bug fixes is 18557 quite large, so it is strongly recommended that users of earlier GCC 18558 3.x releases upgrade to GCC 3.2.1. 18559 18560 Internal Compiler Errors (multi-platform) 18561 18562 * [129]2521: (c++) ICE in build_ptrmemfunc, in cp/typeck.c 18563 * [130]5661: (c++) ICE instantiating template on array of unknown 18564 size (bad code) 18565 * [131]6419: (c++) ICE in make_decl_rtl for "longest" attribute on 18566 64-bit platforms 18567 * [132]6994: (c++) ICE in find_function_data 18568 * [133]7150: preprocessor: GCC -dM -E gives an ICE 18569 * [134]7160: ICE when optimizing branches without a return value 18570 * [135]7228: (c++) ICE when using member template and template 18571 function 18572 * [136]7266: (c++) ICE with -pedantic on missing typename 18573 * [137]7353: ICE from use of "Naming Types" extension, see above 18574 * [138]7411: ICE in instantiate_virtual_regs_1, in function.c 18575 * [139]7478: (c++) ICE on static_cast inside template 18576 * [140]7526: preprocessor core dump when _Pragma implies #pragma 18577 dependency 18578 * [141]7721: (c++) ICE on simple (but incorrect) template ([142]7803 18579 is a duplicate) 18580 * [143]7754: (c++) ICE on union with template parameter 18581 * [144]7788: (c++) redeclaring a definition as an incomplete class 18582 causes ICE 18583 * [145]8031: (c++) ICE in comptypes, in cp/typeck.c 18584 * [146]8055: preprocessor dies with SIG11 when building FreeBSD 18585 kernel 18586 * [147]8067: (c++) ICE due to mishandling of __FUNCTION__ and related 18587 variables 18588 * [148]8134: (c++) ICE in force_store_init_value on legal code 18589 * [149]8149: (c++) ICE on incomplete type 18590 * [150]8160: (c++) ICE in build_modify_expr, in cp/typeck.c: array 18591 initialization 18592 18593 C++ (compiler and library) bugs 18594 18595 * [151]5607: No pointer adjustment in covariant return types 18596 * [152]6579: Infinite loop with statement expressions in member 18597 initialization 18598 * [153]6803: Default copy constructor bug in GCC 3.1 18599 * [154]7176: g++ confused by friend and static member with same name 18600 * [155]7188: Segfault with template class and recursive (incorrect) 18601 initializer list 18602 * [156]7306: Regression: GCC 3.x fails to compile code with virtual 18603 inheritance if a method has a variable number of arguments 18604 * [157]7461: ctype<char>::classic_table() returns offset array on 18605 Cygwin 18606 * [158]7524: f(const float arg[3]) fails 18607 * [159]7584: Erroneous ambiguous base error on using declaration 18608 * [160]7676: Member template overloading problem 18609 * [161]7679: infinite loop when a right parenthesis is missing 18610 * [162]7811: default locale not taken from environment 18611 * [163]7961: compare( char *) implemented incorrectly in 18612 basic_string<> 18613 * [164]8071: basic_ostream::operator<<(streambuf*) loops forever if 18614 streambuf::underflow() leaves gptr() NULL (dups: [165]8127, 18615 [166]6745) 18616 * [167]8096: deque::at() throws std::range_error instead of 18617 std::out_of_range 18618 * [168]8127: cout << cin.rdbuf() infinite loop 18619 * [169]8218: Excessively large memory consumed for classes with large 18620 array members 18621 * [170]8287: GCC 3.2: Destructor called for non-constructed local 18622 object 18623 * [171]8347: empty vector range used in string construction causes 18624 core dump 18625 * [172]8348: fail() flag is set in istringstream when eof() flag is 18626 set 18627 * [173]8391: regression: infinite loop in cp/decl2.c(finish_file) 18628 18629 C and optimizer bugs 18630 18631 * [174]6627: -fno-align-functions doesn't seem to disable function 18632 alignment 18633 * [175]6631: life_analysis misoptimizes code to initialize fields of 18634 a structure 18635 * [176]7102: unsigned char division results in floating exception 18636 * [177]7120: Run once loop should *always* be unrolled 18637 (pessimization) 18638 * [178]7209: Bug involving array referencing and ?: operator 18639 * [179]7515: invalid inlining of global function with -O3 18640 * [180]7814: incorrect scheduling for glibc-2.2.92 strcpy test 18641 * [181]8467: bug in sibling call optimization 18642 18643 Preprocessor bugs 18644 18645 * [182]4890: incorrect line markers from the traditional preprocessor 18646 * [183]7357: -M option omits system headers files (making it the same 18647 as -MM) 18648 * [184]7358: Changes to Sun's make Dependencies 18649 * [185]7602: C++ header files found in CPLUS_INCLUDE_PATH treated as 18650 C headers 18651 * [186]7862: Interrupting GCC -MD removes .d file but not .o 18652 * [187]8190: Failed compilation deletes -MD dependency file 18653 * [188]8524: _Pragma within macro is improperly expanded 18654 18655 x86 specific (Intel/AMD) 18656 18657 * [189]5351: (i686-only) function pass-by-value structure copy 18658 corrupts stack ([190]7591 is a duplicate) 18659 * [191]6845, [192]7034, [193]7124, [194]7174: ICE's with 18660 -march=pentium3/pentium2/athlon (these are all the same underlying 18661 bug, in MMX register use) 18662 * [195]7134, [196]7375, [197]7390: ICE with -march=athlon (maybe same 18663 as above?) 18664 * [198]6890: xmmintrin.h, _MM_TRANSPOSE4_PS is broken 18665 * [199]6981: wrong code in 64-bit manipulation on x86 18666 * [200]7242: GCC -mcpu=pentium[23] doesn't define __tune_pentiumpro__ 18667 macro 18668 * [201]7396: ix86: cmpgt_ss, cmpge_ss, cmpngt_ss, and cmpnge_ss SSE 18669 intrinsics are broken 18670 * [202]7630: GCC 3.2 breaks on Mozilla 1.0's JS sources with 18671 -march=pentium4 18672 * [203]7693: Typo in i386 mmintrin.h header 18673 * [204]7723: ICE - Pentium3 sse - GCC 3.2 18674 * [205]7951: ICE on -march=pentium4 -O2 -mfpmath=sse 18675 * [206]8146: (i686 only) gcc 3.2 miscompiles gcc 2.95.3 18676 18677 PowerPC specific 18678 18679 * [207]5967: GCC bug when profiling nested functions on powerpc 18680 * [208]6984: wrong code generated with -O2, -O3, -Os for do-while 18681 loop on PowerPC 18682 * [209]7114: PowerPC: ICE building strcoll.op from glibc-2.2.5 18683 * [210]7130: miscompiled code for GCC-3.1 on 18684 powerpc-unknown-linux-gnu with -funroll-all-loops 18685 * [211]7133: PowerPC ICE: unrecognizable insn 18686 * [212]7380: ICE in extract_insn, at recog.c:2148 18687 * [213]8252: ICE on Altivec code with optimization turned on 18688 * [214]8451: Altivec ICE in GCC 3.2 18689 18690 HP/PA specific 18691 18692 * [215]7250: __ashrdi3 returns wrong value on 32 bit hppa 18693 18694 SPARC specific 18695 18696 * [216]6668: when using --disable-multilib, libgcc_s.so is installed 18697 in the wrong place on sparc-solaris 18698 * [217]7151: ICE when compiling for UltraSPARC 18699 * [218]7335: SPARC: ICE in verify_wide_reg (flow.c:557) with long 18700 double and -O1 18701 * [219]7842: [REGRESSION] SPARC code gen bug 18702 18703 ARM specific 18704 18705 * [220]7856: [arm] invalid offset in constant pool reference 18706 * [221]7967: optimization produces wrong code (ARM) 18707 18708 Alpha specific 18709 18710 * [222]7374: __builtin_fabsl broken on alpha 18711 18712 IBM s390 specific 18713 18714 * [223]7370: ICE in fixup_var_refs_1 on s390x 18715 * [224]7409: loop optimization bug on s390x-linux-gnu 18716 * [225]8232: s390x: ICE when using bcmp with int length argument 18717 18718 SCO specific 18719 18720 * [226]7623: SCO OpenServer build fails with machmode.def: undefined 18721 symbol: BITS_PER_UNIT 18722 18723 m68k/Coldfire specific 18724 18725 * [227]8314: crtbegin, crtend need to be multilib'ed for this 18726 platform 18727 18728 Documentation 18729 18730 * [228]761: Document some undocumented options 18731 * [229]5610: Fix documentation about invoking SSE instructions 18732 (-mfpmath=sse) 18733 * [230]7484: List -Wmissing-declarations as C-only option 18734 * [231]7531: -mcmodel not documented for x86-64 18735 * [232]8120: Update documentation of bad use of ## 18736 __________________________________________________________________ 18737 18738 GCC 3.2 18739 18740 3.2 is a small bug fix release, but there is a change to the 18741 application binary interface (ABI), hence the change to the second part 18742 of the version number. 18743 18744 The main purpose of the 3.2 release is to correct a couple of problems 18745 in the C++ ABI, with the intention of providing a stable interface 18746 going forward. Accordingly, 3.2 is only a small change to 3.1.1. 18747 18748 Bug Fixes 18749 18750 C++ 18751 18752 * [233]7320: g++ 3.2 relocation problem 18753 * [234]7470: vtable: virtual function pointers not in declaration 18754 order 18755 18756 libstdc++ 18757 18758 * [235]6410: Trouble with non-ASCII monetary symbols and wchar_t 18759 * [236]6503, [237]6642, [238]7186: Problems with comparing or 18760 subtracting various types of const and non-const iterators 18761 * [239]7216: ambiguity with basic_iostream::traits_type 18762 * [240]7220: problem with basic_istream::ignore(0,delimiter) 18763 * [241]7222: locale::operator==() doesn't work on std::locale("") 18764 * [242]7286: placement operator delete issue 18765 * [243]7442: cxxabi.h does not match the C++ ABI 18766 * [244]7445: poor performance of std::locale::classic() in 18767 multi-threaded applications 18768 18769 x86-64 specific 18770 18771 * [245]7291: off-by-one in generated inline bzero code for x86-64 18772 18773 18774 For questions related to the use of GCC, please consult these web 18775 pages and the [246]GCC manuals. If that fails, the 18776 [247]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 18777 web pages and the development of GCC are welcome on our developer 18778 list at [248]gcc (a] gcc.gnu.org. All of [249]our lists have public 18779 archives. 18780 18781 Copyright (C) [250]Free Software Foundation, Inc. Verbatim copying and 18782 distribution of this entire article is permitted in any medium, 18783 provided this notice is preserved. 18784 18785 These pages are [251]maintained by the GCC team. Last modified 18786 2021-07-28[252]. 18787 18788 References 18789 18790 1. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 18791 2. http://gcc.gnu.org/gcc-3.1/changes.html 18792 3. http://gcc.gnu.org/gcc-3.2/c++-abi.html 18793 4. https://gcc.gnu.org/PR3782 18794 5. https://gcc.gnu.org/PR6440 18795 6. https://gcc.gnu.org/PR7050 18796 7. https://gcc.gnu.org/PR7741 18797 8. https://gcc.gnu.org/PR7982 18798 9. https://gcc.gnu.org/PR8068 18799 10. https://gcc.gnu.org/PR8178 18800 11. https://gcc.gnu.org/PR8396 18801 12. https://gcc.gnu.org/PR8674 18802 13. https://gcc.gnu.org/PR9768 18803 14. https://gcc.gnu.org/PR9798 18804 15. https://gcc.gnu.org/PR9799 18805 16. https://gcc.gnu.org/PR9928 18806 17. https://gcc.gnu.org/PR10114 18807 18. https://gcc.gnu.org/PR10352 18808 19. https://gcc.gnu.org/PR10336 18809 20. https://gcc.gnu.org/PR8224 18810 21. https://gcc.gnu.org/PR8613 18811 22. https://gcc.gnu.org/PR8828 18812 23. https://gcc.gnu.org/PR9226 18813 24. https://gcc.gnu.org/PR9853 18814 25. https://gcc.gnu.org/PR9797 18815 26. https://gcc.gnu.org/PR9967 18816 27. https://gcc.gnu.org/PR10116 18817 28. https://gcc.gnu.org/PR10171 18818 29. https://gcc.gnu.org/PR10175 18819 30. https://gcc.gnu.org/PR8316 18820 31. https://gcc.gnu.org/PR9169 18821 32. https://gcc.gnu.org/PR9420 18822 33. https://gcc.gnu.org/PR9459 18823 34. https://gcc.gnu.org/PR9507 18824 35. https://gcc.gnu.org/PR9538 18825 36. https://gcc.gnu.org/PR9602 18826 37. https://gcc.gnu.org/PR9993 18827 38. https://gcc.gnu.org/PR10167 18828 39. https://gcc.gnu.org/PR9652 18829 40. https://gcc.gnu.org/PR10144 18830 41. https://gcc.gnu.org/PR8746 18831 42. https://gcc.gnu.org/PR9888 18832 43. https://gcc.gnu.org/PR9638 18833 44. https://gcc.gnu.org/PR9954 18834 45. https://gcc.gnu.org/PR7784 18835 46. https://gcc.gnu.org/PR7796 18836 47. https://gcc.gnu.org/PR8281 18837 48. https://gcc.gnu.org/PR8366 18838 49. https://gcc.gnu.org/PR8726 18839 50. https://gcc.gnu.org/PR9414 18840 51. https://gcc.gnu.org/PR10067 18841 52. https://gcc.gnu.org/PR7248 18842 53. https://gcc.gnu.org/PR8343 18843 54. https://gcc.gnu.org/PR9732 18844 55. https://gcc.gnu.org/PR10073 18845 56. https://gcc.gnu.org/PR7702 18846 57. https://gcc.gnu.org/PR9671 18847 58. https://gcc.gnu.org/PR8694 18848 59. https://gcc.gnu.org/PR9953 18849 60. https://gcc.gnu.org/PR10271 18850 61. https://gcc.gnu.org/PR6362 18851 62. https://gcc.gnu.org/PR10377 18852 63. https://gcc.gnu.org/PR6955 18853 64. https://gcc.gnu.org/PR5919 18854 65. https://gcc.gnu.org/PR7129 18855 66. https://gcc.gnu.org/PR7507 18856 67. https://gcc.gnu.org/PR7622 18857 68. https://gcc.gnu.org/PR7681 18858 69. https://gcc.gnu.org/PR9528 18859 70. https://gcc.gnu.org/PR8031 18860 71. https://gcc.gnu.org/PR8275 18861 72. https://gcc.gnu.org/PR8332 18862 73. https://gcc.gnu.org/PR8372 18863 74. https://gcc.gnu.org/PR8439 18864 75. https://gcc.gnu.org/PR8442 18865 76. https://gcc.gnu.org/PR8518 18866 77. https://gcc.gnu.org/PR8615 18867 78. 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105. https://gcc.gnu.org/PR8794 18895 106. https://gcc.gnu.org/PR8832 18896 107. https://gcc.gnu.org/PR8988 18897 108. https://gcc.gnu.org/PR9492 18898 109. https://gcc.gnu.org/PR9267 18899 110. https://gcc.gnu.org/PR8344 18900 111. https://gcc.gnu.org/PR8524 18901 112. https://gcc.gnu.org/PR8880 18902 113. https://gcc.gnu.org/PR9090 18903 114. https://gcc.gnu.org/PR8588 18904 115. https://gcc.gnu.org/PR8599 18905 116. https://gcc.gnu.org/PR9506 18906 117. https://gcc.gnu.org/PR9484 18907 118. https://gcc.gnu.org/PR9292 18908 119. https://gcc.gnu.org/PR9293 18909 120. https://gcc.gnu.org/PR9295 18910 121. https://gcc.gnu.org/PR9296 18911 122. https://gcc.gnu.org/PR9316 18912 123. https://gcc.gnu.org/PR9493 18913 124. https://gcc.gnu.org/PR7341 18914 125. https://gcc.gnu.org/PR8947 18915 126. https://gcc.gnu.org/PR7448 18916 127. https://gcc.gnu.org/PR8882 18917 128. https://gcc.gnu.org/PR7445 18918 129. https://gcc.gnu.org/PR2521 18919 130. https://gcc.gnu.org/PR5661 18920 131. 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https://gcc.gnu.org/PR7357 18973 184. https://gcc.gnu.org/PR7358 18974 185. https://gcc.gnu.org/PR7602 18975 186. https://gcc.gnu.org/PR7862 18976 187. https://gcc.gnu.org/PR8190 18977 188. https://gcc.gnu.org/PR8524 18978 189. https://gcc.gnu.org/PR5351 18979 190. https://gcc.gnu.org/PR7591 18980 191. https://gcc.gnu.org/PR6845 18981 192. https://gcc.gnu.org/PR7034 18982 193. https://gcc.gnu.org/PR7124 18983 194. https://gcc.gnu.org/PR7174 18984 195. https://gcc.gnu.org/PR7134 18985 196. https://gcc.gnu.org/PR7375 18986 197. https://gcc.gnu.org/PR7390 18987 198. https://gcc.gnu.org/PR6890 18988 199. https://gcc.gnu.org/PR6981 18989 200. https://gcc.gnu.org/PR7242 18990 201. https://gcc.gnu.org/PR7396 18991 202. https://gcc.gnu.org/PR7630 18992 203. https://gcc.gnu.org/PR7693 18993 204. https://gcc.gnu.org/PR7723 18994 205. https://gcc.gnu.org/PR7951 18995 206. https://gcc.gnu.org/PR8146 18996 207. https://gcc.gnu.org/PR5967 18997 208. https://gcc.gnu.org/PR6984 18998 209. https://gcc.gnu.org/PR7114 18999 210. https://gcc.gnu.org/PR7130 19000 211. https://gcc.gnu.org/PR7133 19001 212. https://gcc.gnu.org/PR7380 19002 213. https://gcc.gnu.org/PR8252 19003 214. https://gcc.gnu.org/PR8451 19004 215. https://gcc.gnu.org/PR7250 19005 216. https://gcc.gnu.org/PR6668 19006 217. https://gcc.gnu.org/PR7151 19007 218. https://gcc.gnu.org/PR7335 19008 219. https://gcc.gnu.org/PR7842 19009 220. https://gcc.gnu.org/PR7856 19010 221. https://gcc.gnu.org/PR7967 19011 222. https://gcc.gnu.org/PR7374 19012 223. https://gcc.gnu.org/PR7370 19013 224. https://gcc.gnu.org/PR7409 19014 225. https://gcc.gnu.org/PR8232 19015 226. https://gcc.gnu.org/PR7623 19016 227. https://gcc.gnu.org/PR8314 19017 228. https://gcc.gnu.org/PR761 19018 229. https://gcc.gnu.org/PR5610 19019 230. https://gcc.gnu.org/PR7484 19020 231. https://gcc.gnu.org/PR7531 19021 232. https://gcc.gnu.org/PR8120 19022 233. https://gcc.gnu.org/PR7320 19023 234. https://gcc.gnu.org/PR7470 19024 235. https://gcc.gnu.org/PR6410 19025 236. https://gcc.gnu.org/PR6503 19026 237. https://gcc.gnu.org/PR6642 19027 238. https://gcc.gnu.org/PR7186 19028 239. https://gcc.gnu.org/PR7216 19029 240. https://gcc.gnu.org/PR7220 19030 241. https://gcc.gnu.org/PR7222 19031 242. https://gcc.gnu.org/PR7286 19032 243. https://gcc.gnu.org/PR7442 19033 244. https://gcc.gnu.org/PR7445 19034 245. https://gcc.gnu.org/PR7291 19035 246. https://gcc.gnu.org/onlinedocs/ 19036 247. mailto:gcc-help (a] gcc.gnu.org 19037 248. mailto:gcc (a] gcc.gnu.org 19038 249. https://gcc.gnu.org/lists.html 19039 250. https://www.fsf.org/ 19040 251. https://gcc.gnu.org/about.html 19041 252. http://validator.w3.org/check/referer 19042 ====================================================================== 19043 http://gcc.gnu.org/gcc-3.1/index.html 19044 GCC 3.1 19045 19046 (This release series is no longer supported.) 19047 19048 July 27, 2002 19049 19050 The [1]GNU project and the GCC developers are pleased to announce the 19051 release of GCC 3.1.1. 19052 19053 The links below still apply to GCC 3.1.1. 19054 19055 May 15, 2002 19056 19057 The [2]GNU project and the GCC developers are pleased to announce the 19058 release of GCC 3.1. 19059 19060 GCC used to stand for the GNU C Compiler, but since the compiler 19061 supports several other languages aside from C, it now stands for the 19062 GNU Compiler Collection. 19063 19064 A list of [3]successful builds is updated as new information becomes 19065 available. 19066 19067 The GCC developers would like to thank the numerous people that have 19068 contributed [4]new features, improvements, bug fixes, and other changes 19069 as well as test results to GCC. This [5]amazing group of volunteers is 19070 what makes GCC successful. 19071 19072 For additional information about GCC please refer to the [6]GCC project 19073 web site or contact the [7]GCC development mailing list. 19074 19075 To obtain GCC please use [8]our mirror sites, or our CVS server. 19076 __________________________________________________________________ 19077 19078 19079 For questions related to the use of GCC, please consult these web 19080 pages and the [9]GCC manuals. If that fails, the 19081 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19082 web pages and the development of GCC are welcome on our developer 19083 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 19084 archives. 19085 19086 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 19087 distribution of this entire article is permitted in any medium, 19088 provided this notice is preserved. 19089 19090 These pages are [14]maintained by the GCC team. Last modified 19091 2021-07-28[15]. 19092 19093 References 19094 19095 1. http://www.gnu.org/ 19096 2. http://www.gnu.org/ 19097 3. http://gcc.gnu.org/gcc-3.1/buildstat.html 19098 4. http://gcc.gnu.org/gcc-3.1/changes.html 19099 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19100 6. http://gcc.gnu.org/index.html 19101 7. mailto:gcc (a] gcc.gnu.org 19102 8. http://gcc.gnu.org/mirrors.html 19103 9. https://gcc.gnu.org/onlinedocs/ 19104 10. mailto:gcc-help (a] gcc.gnu.org 19105 11. mailto:gcc (a] gcc.gnu.org 19106 12. https://gcc.gnu.org/lists.html 19107 13. https://www.fsf.org/ 19108 14. https://gcc.gnu.org/about.html 19109 15. http://validator.w3.org/check/referer 19110 ====================================================================== 19111 http://gcc.gnu.org/gcc-3.1/changes.html 19112 GCC 3.1 Release Series 19113 Changes, New Features, and Fixes 19114 19115 Additional changes in GCC 3.1.1 19116 19117 * A bug related to how structures and unions are returned has been 19118 fixed for powerpc-*-netbsd*. 19119 * An important bug in the implementation of -fprefetch-loop-arrays 19120 has been fixed. Previously the optimization prefetched random 19121 blocks of memory for most targets except for i386. 19122 * The Java compiler now compiles Java programs much faster and also 19123 works with parallel make. 19124 * Nested functions have been fixed for mips*-*-netbsd*. 19125 * Some missing floating point support routines have beed added for 19126 mips*-*-netbsd*. 19127 * This [1]message gives additional information about the bugs fixed 19128 in this release. 19129 19130 Caveats 19131 19132 * The -traditional C compiler option has been deprecated and will be 19133 removed in GCC 3.3. (It remains possible to preprocess non-C code 19134 with the traditional preprocessor.) 19135 * The default debugging format for most ELF platforms (including 19136 GNU/Linux and FreeBSD; notable exception is Solaris) has changed 19137 from stabs to DWARF2. This requires GDB 5.1.1 or later. 19138 19139 General Optimizer Improvements 19140 19141 * Jan Hubicka, SuSE Labs, together with Richard Henderson, Red Hat, 19142 and Andreas Jaeger, SuSE Labs, has contributed [2]infrastructure 19143 for profile driven optimizations. 19144 Options -fprofile-arcs and -fbranch-probabilities can now be used 19145 to improve speed of the generated code by profiling the actual 19146 program behaviour on typical runs. In the absence of profile info 19147 the compiler attempts to guess the profile statically. 19148 * [3]SPEC2000 and SPEC95 benchmark suites are now used daily to 19149 monitor performance of the generated code. 19150 According to the SPECInt2000 results on an AMD Athlon CPU, the code 19151 generated by GCC 3.1 is 6% faster on the average (8.2% faster with 19152 profile feedback) compared to GCC 3.0. The code produced by GCC 3.0 19153 is about 2.1% faster compared to 2.95.3. Tests were done using the 19154 -O2 -march=athlon command-line options. 19155 * Alexandre Oliva, of Red Hat, has generalized the tree inlining 19156 infrastructure developed by CodeSourcery, LLC for the C++ front 19157 end, so that it is now used in the C front end too. Inlining 19158 functions as trees exposes them earlier to the compiler, giving it 19159 more opportunities for optimization. 19160 * Support for data prefetching instructions has been added to the GCC 19161 back end and several targets. A new __builtin_prefetch intrinsic is 19162 available to explicitly insert prefetch instructions and 19163 experimental support for loop array prefetching has been added (see 19164 -fprefetch-loop-array documentation). 19165 * Support for emitting debugging information for macros has been 19166 added for DWARF2. It is activated using -g3. 19167 19168 New Languages and Language specific improvements 19169 19170 C/C++ 19171 19172 * A few more [4]ISO C99 features. 19173 * The preprocessor is 10-50% faster than the preprocessor in GCC 3.0. 19174 * The preprocessor's symbol table has been merged with the symbol 19175 table of the C, C++ and Objective-C front ends. 19176 * The preprocessor consumes less memory than the preprocessor in GCC 19177 3.0, often significantly so. On normal input files, it typically 19178 consumes less memory than pre-3.0 cccp-based GCC, too. 19179 19180 C++ 19181 19182 * -fhonor-std and -fno-honor-std have been removed. -fno-honor-std 19183 was a workaround to allow std compliant code to work with the 19184 non-std compliant libstdc++-v2. libstdc++-v3 is std compliant. 19185 * The C++ ABI has been fixed so that void (A::*)() const is mangled 19186 as "M1AKFvvE", rather than "MK1AFvvE" as before. This change only 19187 affects pointer to cv-qualified member function types. 19188 * The C++ ABI has been changed to correctly handle this code: 19189 struct A { 19190 void operator delete[] (void *, size_t); 19191 }; 19192 19193 struct B : public A { 19194 }; 19195 19196 new B[10]; 19197 19198 The amount of storage allocated for the array will be greater than 19199 it was in 3.0, in order to store the number of elements in the 19200 array, so that the correct size can be passed to operator delete[] 19201 when the array is deleted. Previously, the value passed to operator 19202 delete[] was unpredictable. 19203 This change will only affect code that declares a two-argument 19204 operator delete[] with a second parameter of type size_t in a base 19205 class, and does not override that definition in a derived class. 19206 * The C++ ABI has been changed so that: 19207 struct A { 19208 void operator delete[] (void *, size_t); 19209 void operator delete[] (void *); 19210 }; 19211 19212 does not cause unnecessary storage to be allocated when an array of 19213 A objects is allocated. 19214 This change will only affect code that declares both of these forms 19215 of operator delete[], and declared the two-argument form before the 19216 one-argument form. 19217 * The C++ ABI has been changed so that when a parameter is passed by 19218 value, any cleanup for that parameter is performed in the caller, 19219 as specified by the ia64 C++ ABI, rather than the called function 19220 as before. As a result, classes with a non-trivial destructor but a 19221 trivial copy constructor will be passed and returned by invisible 19222 reference, rather than by bitwise copy as before. 19223 * G++ now supports the "named return value optimization": for code 19224 like 19225 A f () { 19226 A a; 19227 ... 19228 return a; 19229 } 19230 19231 G++ will allocate a in the return value slot, so that the return 19232 becomes a no-op. For this to work, all return statements in the 19233 function must return the same variable. 19234 * Improvements to the C++ library are listed in [5]the libstdc++-v3 19235 FAQ. 19236 19237 Objective-C 19238 19239 * Annoying linker warnings (due to incorrect code being generated) 19240 have been fixed. 19241 * If a class method cannot be found, the compiler no longer issues a 19242 warning if a corresponding instance method exists in the root 19243 class. 19244 * Forward @protocol declarations have been fixed. 19245 * Loading of categories has been fixed in certain situations (GNU run 19246 time only). 19247 * The class lookup in the run-time library has been rewritten so that 19248 class method dispatch is more than twice as fast as it used to be 19249 (GNU run time only). 19250 19251 Java 19252 19253 * libgcj now includes RMI, java.lang.ref.*, javax.naming, and 19254 javax.transaction. 19255 * Property files and other system resources can be compiled into 19256 executables which use libgcj using the new gcj --resource feature. 19257 * libgcj has been ported to more platforms. In particular there is 19258 now a mostly-functional mingw32 (Windows) target port. 19259 * JNI and CNI invocation interfaces were implemented, so gcj-compiled 19260 Java code can now be called from a C/C++ application. 19261 * gcj can now use builtin functions for certain known methods, for 19262 instance Math.cos. 19263 * gcj can now automatically remove redundant array-store checks in 19264 some common cases. 19265 * The --no-store-checks optimization option was added. This can be 19266 used to omit runtime store checks for code which is known not to 19267 throw ArrayStoreException 19268 * The following third party interface standards were added to libgcj: 19269 org.w3c.dom and org.xml.sax. 19270 * java.security has been merged with GNU Classpath. The new package 19271 is now JDK 1.2 compliant, and much more complete. 19272 * A bytecode verifier was added to the libgcj interpreter. 19273 * java.lang.Character was rewritten to comply with the Unicode 3.0 19274 standard, and improve performance. 19275 * Partial support for many more locales was added to libgcj. 19276 * Socket timeouts have been implemented. 19277 * libgcj has been merged into a single shared library. There are no 19278 longer separate shared libraries for the garbage collector and 19279 zlib. 19280 * Several performance improvements were made to gcj and libgcj: 19281 + Hash synchronization (thin locks) 19282 + A special allocation path for finalizer-free objects 19283 + Thread-local allocation 19284 + Parallel GC, and other GC tweaks 19285 19286 Fortran 19287 19288 Fortran improvements are listed in [6]the Fortran documentation. 19289 19290 Ada 19291 19292 [7]AdaCore, has contributed its GNAT Ada 95 front end and associated 19293 tools. The GNAT compiler fully implements the Ada language as defined 19294 by the ISO/IEC 8652 standard. 19295 19296 Please note that the integration of the Ada front end is still work in 19297 progress. 19298 19299 New Targets and Target Specific Improvements 19300 19301 * Hans-Peter Nilsson has contributed a port to MMIX, the CPU 19302 architecture used in new editions of Donald E. Knuth's The Art of 19303 Computer Programming. 19304 * Axis Communications has contributed its port to the CRIS CPU 19305 architecture, used in the ETRAX system-on-a-chip series. 19306 * Alexandre Oliva, of Red Hat, has contributed a port to the SuperH 19307 SH5 64-bit RISC microprocessor architecture, extending the existing 19308 SH port. 19309 * UltraSPARC is fully supported in 64-bit mode. The option -m64 19310 enables it. 19311 * For compatibility with the Sun compiler #pragma redefine_extname 19312 has been implemented on Solaris. 19313 * The x86 back end has had some noticeable work done to it. 19314 + SuSE Labs developers Jan Hubicka, Bo Thorsen and Andreas 19315 Jaeger have contributed a port to the AMD x86-64 architecture. 19316 For more information on x86-64 see http://www.x86-64.org. 19317 + The compiler now supports MMX, 3DNow!, SSE, and SSE2 19318 instructions. Options -mmmx, -m3dnow, -msse, and -msse2 will 19319 enable the respective instruction sets. Intel C++ compatible 19320 MMX/3DNow!/SSE intrinsics are implemented. SSE2 intrinsics 19321 will be added in next major release. 19322 + Following those improvements, targets for Pentium MMX, K6-2, 19323 K6-3, Pentium III, Pentium 4, and Athlon 4 Mobile/XP/MP were 19324 added. Refer to the documentation on -march= and -mcpu= 19325 options for details. 19326 + For those targets that support it, -mfpmath=sse will cause the 19327 compiler to generate SSE/SSE2 instructions for floating point 19328 math instead of x87 instructions. Usually, this will lead to 19329 quicker code especially on the Pentium 4. Note that only 19330 scalar floating point instructions are used and GCC does not 19331 exploit SIMD features yet. 19332 + Prefetch support has been added to the Pentium III, Pentium 4, 19333 K6-2, K6-3, and Athlon series. 19334 + Code generated for floating point to integer conversions has 19335 been improved leading to better performance of many 3D 19336 applications. 19337 * The PowerPC back end has added 64-bit PowerPC GNU/Linux support. 19338 * C++ support for AIX has been improved. 19339 * Aldy Hernandez, of Red Hat, Inc, has contributed extensions to the 19340 PowerPC port supporting the AltiVec programming model (SIMD). The 19341 support, though presently useful, is experimental and is expected 19342 to stabilize for 3.2. The support is written to conform to 19343 Motorola's AltiVec specs. See -maltivec. 19344 19345 Obsolete Systems 19346 19347 Support for a number of older systems has been declared obsolete in GCC 19348 3.1. Unless there is activity to revive them, the next release of GCC 19349 will have their sources permanently removed. 19350 19351 All configurations of the following processor architectures have been 19352 declared obsolete: 19353 * MIL-STD-1750A, 1750a-*-* 19354 * AMD A29k, a29k-*-* 19355 * Convex, c*-convex-* 19356 * Clipper, clipper-*-* 19357 * Elxsi, elxsi-*-* 19358 * Intel i860, i860-*-* 19359 * Sun picoJava, pj-*-* and pjl-*-* 19360 * Western Electric 32000, we32k-*-* 19361 19362 Most configurations of the following processor architectures have been 19363 declared obsolete, but we are preserving a few systems which may have 19364 active developers. It is unlikely that the remaining systems will 19365 survive much longer unless we see definite signs of port activity. 19366 * Motorola 88000 except 19367 + Generic a.out, m88k-*-aout* 19368 + Generic SVR4, m88k-*-sysv4 19369 + OpenBSD, m88k-*-openbsd* 19370 * NS32k except 19371 + NetBSD, ns32k-*-netbsd* 19372 + OpenBSD, ns32k-*-openbsd*. 19373 * ROMP except 19374 + OpenBSD, romp-*-openbsd*. 19375 19376 Finally, only some configurations of these processor architectures are 19377 being obsoleted. 19378 * Alpha: 19379 + OSF/1, alpha*-*-osf[123]*. (Digital Unix and Tru64 Unix, aka 19380 alpha*-*-osf[45], are still supported.) 19381 * ARM: 19382 + RISCiX, arm-*-riscix*. 19383 * i386: 19384 + 386BSD, i?86-*-bsd* 19385 + Chorus, i?86-*-chorusos* 19386 + DG/UX, i?86-*-dgux* 19387 + FreeBSD 1.x, i?86-*-freebsd1.* 19388 + IBM AIX, i?86-*-aix* 19389 + ISC UNIX, i?86-*-isc* 19390 + GNU/Linux with pre-BFD linker, i?86-*-linux*oldld* 19391 + NEXTstep, i?86-next-* 19392 + OSF UNIX, i?86-*-osf1* and i?86-*-osfrose* 19393 + RTEMS/coff, i?86-*-rtemscoff* 19394 + RTEMS/go32, i?86-go32-rtems* 19395 + Sequent/BSD, i?86-sequent-bsd* 19396 + Sequent/ptx before version 3, i?86-sequent-ptx[12]* and 19397 i?86-sequent-sysv3* 19398 + SunOS, i?86-*-sunos* 19399 * Motorola 68000: 19400 + Altos, m68[k0]*-altos-* 19401 + Apollo, m68[k0]*-apollo-* 19402 + Apple A/UX, m68[k0]*-apple-* 19403 + Bull, m68[k0]*-bull-* 19404 + Convergent, m68[k0]*-convergent-* 19405 + Generic SVR3, m68[k0]*-*-sysv3* 19406 + ISI, m68[k0]*-isi-* 19407 + LynxOS, m68[k0]*-*-lynxos* 19408 + NEXT, m68[k0]*-next-* 19409 + RTEMS/coff, m68[k0]*-*-rtemscoff* 19410 + Sony, m68[k0]*-sony-* 19411 * MIPS: 19412 + DEC Ultrix, mips-*-ultrix* and mips-dec-* 19413 + Generic BSD, mips-*-bsd* 19414 + Generic System V, mips-*-sysv* 19415 + IRIX before version 5, mips-sgi-irix[1234]* 19416 + RiscOS, mips-*-riscos* 19417 + Sony, mips-sony-* 19418 + Tandem, mips-tandem-* 19419 * SPARC: 19420 + RTEMS/a.out, sparc-*-rtemsaout*. 19421 19422 Documentation improvements 19423 19424 * The old manual ("Using and Porting the GNU Compiler Collection") 19425 has been replaced by a users manual ("Using the GNU Compiler 19426 Collection") and a separate internals reference manual ("GNU 19427 Compiler Collection Internals"). 19428 * More complete and much improved documentation about GCC's internal 19429 representation used by the C and C++ front ends. 19430 * Many cleanups and improvements in general. 19431 19432 19433 For questions related to the use of GCC, please consult these web 19434 pages and the [8]GCC manuals. If that fails, the 19435 [9]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19436 web pages and the development of GCC are welcome on our developer 19437 list at [10]gcc (a] gcc.gnu.org. All of [11]our lists have public 19438 archives. 19439 19440 Copyright (C) [12]Free Software Foundation, Inc. Verbatim copying and 19441 distribution of this entire article is permitted in any medium, 19442 provided this notice is preserved. 19443 19444 These pages are [13]maintained by the GCC team. Last modified 19445 2021-07-28[14]. 19446 19447 References 19448 19449 1. https://gcc.gnu.org/ml/gcc/2002-07/msg01208.html 19450 2. http://gcc.gnu.org/news/profiledriven.html 19451 3. http://gcc.gnu.org/benchmarks/ 19452 4. http://gcc.gnu.org/c99status.html 19453 5. https://gcc.gnu.org/onlinedocs/libstdc++/faq.html 19454 6. https://gcc.gnu.org/onlinedocs/gcc-3.1.1/g77/News.html 19455 7. https://www.adacore.com/ 19456 8. https://gcc.gnu.org/onlinedocs/ 19457 9. mailto:gcc-help (a] gcc.gnu.org 19458 10. mailto:gcc (a] gcc.gnu.org 19459 11. https://gcc.gnu.org/lists.html 19460 12. https://www.fsf.org/ 19461 13. https://gcc.gnu.org/about.html 19462 14. http://validator.w3.org/check/referer 19463 ====================================================================== 19464 http://gcc.gnu.org/gcc-3.0/index.html 19465 GCC 3.0.4 19466 19467 (This release series is no longer supported.) 19468 19469 February 20, 2002 19470 19471 The [1]GNU project and the GCC developers are pleased to announce the 19472 release of GCC 3.0.4, which is a bug-fix release for the GCC 3.0 19473 series. 19474 19475 GCC used to stand for the GNU C Compiler, but since the compiler 19476 supports several other languages aside from C, it now stands for the 19477 GNU Compiler Collection. 19478 19479 GCC 3.0.x has several new optimizations, new targets, new languages and 19480 many other new features, relative to GCC 2.95.x. See the [2]new 19481 features page for a more complete list. 19482 19483 A list of [3]successful builds is updated as new information becomes 19484 available. 19485 19486 The GCC developers would like to thank the numerous people that have 19487 contributed new features, test results, bug fixes, etc to GCC. This 19488 [4]amazing group of volunteers is what makes GCC successful. 19489 19490 And finally, we can't in good conscience fail to mention some 19491 [5]caveats to using GCC 3.0.x. 19492 19493 For additional information about GCC please refer to the [6]GCC project 19494 web site or contact the [7]GCC development mailing list. 19495 19496 To obtain GCC please use [8]our mirror sites, or our CVS server. 19497 __________________________________________________________________ 19498 19499 Previous 3.0.x Releases 19500 19501 December 20, 2001: GCC 3.0.3 has been released. 19502 October 25, 2001: GCC 3.0.2 has been released. 19503 August 20, 2001: GCC 3.0.1 has been released. 19504 June 18, 2001: GCC 3.0 has been released. 19505 19506 19507 For questions related to the use of GCC, please consult these web 19508 pages and the [9]GCC manuals. If that fails, the 19509 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19510 web pages and the development of GCC are welcome on our developer 19511 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 19512 archives. 19513 19514 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 19515 distribution of this entire article is permitted in any medium, 19516 provided this notice is preserved. 19517 19518 These pages are [14]maintained by the GCC team. Last modified 19519 2021-07-28[15]. 19520 19521 References 19522 19523 1. http://www.gnu.org/ 19524 2. http://gcc.gnu.org/gcc-3.0/features.html 19525 3. http://gcc.gnu.org/gcc-3.0/buildstat.html 19526 4. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19527 5. http://gcc.gnu.org/gcc-3.0/caveats.html 19528 6. http://gcc.gnu.org/index.html 19529 7. mailto:gcc (a] gcc.gnu.org 19530 8. http://gcc.gnu.org/mirrors.html 19531 9. https://gcc.gnu.org/onlinedocs/ 19532 10. mailto:gcc-help (a] gcc.gnu.org 19533 11. mailto:gcc (a] gcc.gnu.org 19534 12. https://gcc.gnu.org/lists.html 19535 13. https://www.fsf.org/ 19536 14. https://gcc.gnu.org/about.html 19537 15. http://validator.w3.org/check/referer 19538 ====================================================================== 19539 http://gcc.gnu.org/gcc-3.0/features.html 19540 GCC 3.0 New Features 19541 19542 Additional changes in GCC 3.0.4 19543 19544 * GCC 3.0 now supports newer versions of the [1]NetBSD operating 19545 system, which use the ELF object file format, on x86 processors. 19546 * Correct debugging information is generated from functions that have 19547 lines from multiple files (e.g. yacc output). 19548 * A fix for whitespace handling in the -traditional preprocessor, 19549 which can affect Fortran. 19550 * Fixes to the exception handling runtime. 19551 * More fixes for bad code generation in C++. 19552 * A fix for shared library generation under AIX 4.3. 19553 * Documentation updates. 19554 * Port of GCC to Tensilica's Xtensa processor contributed. 19555 * A fix for compiling the PPC Linux kernel (FAT fs wouldn't link). 19556 19557 Additional changes in GCC 3.0.3 19558 19559 * A fix to correct an accidental change to the PowerPC ABI. 19560 * Fixes for bad code generation on a variety of architectures. 19561 * Improvements to the debugging information generated for C++ 19562 classes. 19563 * Fixes for bad code generation in C++. 19564 * A fix to avoid crashes in the C++ demangler. 19565 * A fix to the C++ standard library to avoid buffer overflows. 19566 * Miscellaneous improvements for a variety of architectures. 19567 19568 Additional changes in GCC 3.0.2 19569 19570 * Fixes for bad code generation during loop unrolling. 19571 * Fixes for bad code generation by the sibling call optimization. 19572 * Minor improvements to x86 code generation. 19573 * Implementation of function descriptors in C++ vtables for IA64. 19574 * Numerous minor bug-fixes. 19575 19576 Additional changes in GCC 3.0.1 19577 19578 * C++ fixes for incorrect code-generation. 19579 * Improved cross-compiling support for the C++ standard library. 19580 * Fixes for some embedded targets that worked in GCC 2.95.3, but not 19581 in GCC 3.0. 19582 * Fixes for various exception-handling bugs. 19583 * A port to the S/390 architecture. 19584 19585 General Optimizer Improvements 19586 19587 * [2]Basic block reordering pass. 19588 * New if-conversion pass with support for conditional (predicated) 19589 execution. 19590 * New tail call and sibling call elimination optimizations. 19591 * New register renaming pass. 19592 * New (experimental) [3]static single assignment (SSA) representation 19593 support. 19594 * New dead-code elimination pass implemented using the SSA 19595 representation. 19596 * [4]Global null pointer test elimination. 19597 * [5]Global code hoisting/unification. 19598 * More builtins and optimizations for stdio.h, string.h and old BSD 19599 functions, as well as for ISO C99 functions. 19600 * New builtin __builtin_expect for giving hints to the branch 19601 predictor. 19602 19603 New Languages and Language specific improvements 19604 19605 * The GNU Compiler for the Java(TM) language (GCJ) is now integrated 19606 and supported, including the run-time library containing most 19607 common non-GUI Java classes, a bytecode interpreter, and the Boehm 19608 conservative garbage collector. Many bugs have been fixed. GCJ can 19609 compile Java source or Java bytecodes to either native code or Java 19610 class files, and supports native methods written in either the 19611 standard JNI or the more efficient and convenient CNI. 19612 * Here is a [6]partial list of C++ improvements, both new features 19613 and those no longer supported. 19614 * New C++ ABI. On the IA-64 platform GCC is capable of 19615 inter-operating with other IA-64 compilers. 19616 * The new ABI also significantly reduces the size of symbol and debug 19617 information. 19618 * New C++ support library and many C++ bug fixes, vastly improving 19619 our conformance to the ISO C++ standard. 19620 * New [7]inliner for C++. 19621 * Rewritten C preprocessor, integrated into the C, C++ and Objective 19622 C compilers, with very many improvements including ISO C99 support 19623 and [8]improvements to dependency generation. 19624 * Support for more [9]ISO C99 features. 19625 * Many improvements to support for checking calls to format functions 19626 such as printf and scanf, including support for ISO C99 format 19627 features, extensions from the Single Unix Specification and GNU 19628 libc 2.2, checking of strfmon formats and features to assist in 19629 auditing for format string security bugs. 19630 * New warnings for C code that may have undefined semantics because 19631 of violations of sequence point rules in the C standard (such as a 19632 = a++;, a[n] = b[n++]; and a[i++] = i;), included in -Wall. 19633 * Additional warning option -Wfloat-equal. 19634 * Improvements to -Wtraditional. 19635 * Fortran improvements are listed in [10]the Fortran documentation. 19636 19637 New Targets and Target Specific Improvements 19638 19639 * New x86 back end, generating much improved code. 19640 * Support for a generic i386-elf target contributed. 19641 * New option to emit x86 assembly code using Intel style syntax 19642 (-mintel-syntax). 19643 * HPUX 11 support contributed. 19644 * Improved PowerPC code generation, including scheduled prologue and 19645 epilogue. 19646 * Port of GCC to Intel's IA-64 processor contributed. 19647 * Port of GCC to Motorola's MCore 210 and 340 contributed. 19648 * New unified back-end for Arm, Thumb and StrongArm contributed. 19649 * Port of GCC to Intel's XScale processor contributed. 19650 * Port of GCC to Atmel's AVR microcontrollers contributed. 19651 * Port of GCC to Mitsubishi's D30V processor contributed. 19652 * Port of GCC to Matsushita's AM33 processor (a member of the MN10300 19653 processor family) contributed. 19654 * Port of GCC to Fujitsu's FR30 processor contributed. 19655 * Port of GCC to Motorola's 68HC11 and 68HC12 processors contributed. 19656 * Port of GCC to Sun's picoJava processor core contributed. 19657 19658 Documentation improvements 19659 19660 * Substantially rewritten and improved C preprocessor manual. 19661 * Many improvements to other documentation. 19662 * Manpages for gcc, cpp and gcov are now generated automatically from 19663 the master Texinfo manual, eliminating the problem of manpages 19664 being out of date. (The generated manpages are only extracts from 19665 the full manual, which is provided in Texinfo form, from which 19666 info, HTML, other formats and a printed manual can be generated.) 19667 * Generated info files are included in the release tarballs alongside 19668 their Texinfo sources, avoiding problems on some platforms with 19669 building makeinfo as part of the GCC distribution. 19670 19671 Other significant improvements 19672 19673 * Garbage collection used internally by the compiler for most memory 19674 allocation instead of obstacks. 19675 * Lengauer and Tarjan algorithm used for computing dominators in the 19676 CFG. This algorithm can be significantly faster and more space 19677 efficient than our older algorithm. 19678 * gccbug script provided to assist in submitting bug reports to our 19679 bug tracking system. (Bug reports previously submitted directly to 19680 our mailing lists, for which you received no bug tracking number, 19681 should be submitted again using gccbug if you can reproduce the 19682 problem with GCC 3.0.) 19683 * The internal libgcc library is [11]built as a shared library on 19684 systems that support it. 19685 * Extensive testsuite included with GCC, with many new tests. In 19686 addition to tests for GCC bugs that have been fixed, many tests 19687 have been added for language features, compiler warnings and 19688 builtin functions. 19689 * Additional language-independent warning options -Wpacked, -Wpadded, 19690 -Wunreachable-code and -Wdisabled-optimization. 19691 * Target-independent options -falign-functions, -falign-loops and 19692 -falign-jumps. 19693 19694 Plus a great many bug fixes and almost all the [12]features found in 19695 GCC 2.95. 19696 19697 19698 For questions related to the use of GCC, please consult these web 19699 pages and the [13]GCC manuals. If that fails, the 19700 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19701 web pages and the development of GCC are welcome on our developer 19702 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 19703 archives. 19704 19705 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 19706 distribution of this entire article is permitted in any medium, 19707 provided this notice is preserved. 19708 19709 These pages are [18]maintained by the GCC team. Last modified 19710 2021-07-28[19]. 19711 19712 References 19713 19714 1. http://www.netbsd.org/ 19715 2. http://gcc.gnu.org/news/reorder.html 19716 3. http://gcc.gnu.org/news/ssa.html 19717 4. http://gcc.gnu.org/news/null.html 19718 5. http://gcc.gnu.org/news/unify.html 19719 6. http://gcc.gnu.org/gcc-3.0/c++features.html 19720 7. http://gcc.gnu.org/news/inlining.html 19721 8. http://gcc.gnu.org/news/dependencies.html 19722 9. http://gcc.gnu.org/c99status.html 19723 10. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 19724 11. http://gcc.gnu.org/gcc-3.0/libgcc.html 19725 12. http://gcc.gnu.org/gcc-2.95/features.html 19726 13. https://gcc.gnu.org/onlinedocs/ 19727 14. mailto:gcc-help (a] gcc.gnu.org 19728 15. mailto:gcc (a] gcc.gnu.org 19729 16. https://gcc.gnu.org/lists.html 19730 17. https://www.fsf.org/ 19731 18. https://gcc.gnu.org/about.html 19732 19. http://validator.w3.org/check/referer 19733 ====================================================================== 19734 http://gcc.gnu.org/gcc-3.0/caveats.html 19735 GCC 3.0 Caveats 19736 19737 * -fstrict-aliasing is now part of -O2 and higher optimization 19738 levels. This allows the compiler to assume the strictest aliasing 19739 rules applicable to the language being compiled. For C and C++, 19740 this activates optimizations based on the type of expressions. This 19741 optimization may thus break old, non-compliant code. 19742 * Enumerations are now properly promoted to int in function 19743 parameters and function returns. Normally this change is not 19744 visible, but when using -fshort-enums this is an ABI change. 19745 * The undocumented extension that allowed C programs to have a label 19746 at the end of a compound statement has been deprecated and may be 19747 removed in a future version. Programs that now generate a warning 19748 about this may be fixed by adding a null statement (a single 19749 semicolon) after the label. 19750 * The poorly documented extension that allowed string constants in C, 19751 C++ and Objective C to contain unescaped newlines has been 19752 deprecated and may be removed in a future version. Programs using 19753 this extension may be fixed in several ways: the bare newline may 19754 be replaced by \n, or preceded by \n\, or string concatenation may 19755 be used with the bare newline preceded by \n" and " placed at the 19756 start of the next line. 19757 * The Chill compiler is not included in GCC 3.0, because of the lack 19758 of a volunteer to convert it to use garbage collection. 19759 * Certain non-standard iostream methods from earlier versions of 19760 libstdc++ are not included in libstdc++ v3, i.e. filebuf::attach, 19761 ostream::form, and istream::gets. 19762 * The new C++ ABI is not yet fully supported by current (as of 19763 2001-07-01) releases and development versions of GDB, or any 19764 earlier versions. There is a problem setting breakpoints by line 19765 number, and other related issues that have been fixed in GCC 3.0 19766 but not yet handled in GDB: 19767 [1]https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 19768 19769 19770 For questions related to the use of GCC, please consult these web 19771 pages and the [2]GCC manuals. If that fails, the 19772 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19773 web pages and the development of GCC are welcome on our developer 19774 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 19775 19776 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 19777 distribution of this entire article is permitted in any medium, 19778 provided this notice is preserved. 19779 19780 These pages are [7]maintained by the GCC team. Last modified 19781 2021-07-28[8]. 19782 19783 References 19784 19785 1. https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 19786 2. https://gcc.gnu.org/onlinedocs/ 19787 3. mailto:gcc-help (a] gcc.gnu.org 19788 4. mailto:gcc (a] gcc.gnu.org 19789 5. https://gcc.gnu.org/lists.html 19790 6. https://www.fsf.org/ 19791 7. https://gcc.gnu.org/about.html 19792 8. http://validator.w3.org/check/referer 19793 ====================================================================== 19794 http://gcc.gnu.org/gcc-2.95/index.html 19795 GCC 2.95 19796 19797 (This release series is no longer supported.) 19798 19799 March 16, 2001: The GNU project and the GCC developers are pleased to 19800 announce the release of GCC version 2.95.3. 19801 19802 Release History 19803 19804 GCC 2.95.3 19805 March 16, 2001 19806 19807 GCC 2.95.2 19808 October 27, 1999 19809 19810 GCC 2.95.1 19811 August 19, 1999 19812 19813 GCC 2.95 19814 July 31, 1999. This is the first release of GCC since the April 19815 1999 GCC/EGCS reunification and includes nearly a year's worth 19816 of new development and bugfixes. 19817 19818 References and Acknowledgements 19819 19820 GCC used to stand for the GNU C Compiler, but since the compiler 19821 supports several other languages aside from C, it now stands for the 19822 GNU Compiler Collection. 19823 19824 The whole suite has been extensively [1]regression tested and 19825 [2]package tested. It should be reliable and suitable for widespread 19826 use. 19827 19828 The compiler has several new optimizations, new targets, new languages 19829 and other new features. See the [3]new features page for a more 19830 complete list of new features found in the GCC 2.95 releases. 19831 19832 The sources include installation instructions in both HTML and 19833 plaintext forms in the install directory in the distribution. However, 19834 the most up to date installation instructions and [4]build/test status 19835 are on the web pages. We will update those pages as new information 19836 becomes available. 19837 19838 The GCC developers would like to thank the numerous people that have 19839 contributed new features, test results, bugfixes, etc to GCC. This 19840 [5]amazing group of volunteers is what makes GCC successful. 19841 19842 And finally, we can't in good conscience fail to mention some 19843 [6]caveats to using GCC 2.95. 19844 19845 Download GCC 2.95 from one of our many [7]mirror sites. 19846 19847 For additional information about GCC please see the [8]GCC project web 19848 server or contact the [9]GCC development mailing list. 19849 19850 19851 For questions related to the use of GCC, please consult these web 19852 pages and the [10]GCC manuals. If that fails, the 19853 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19854 web pages and the development of GCC are welcome on our developer 19855 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 19856 archives. 19857 19858 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 19859 distribution of this entire article is permitted in any medium, 19860 provided this notice is preserved. 19861 19862 These pages are [15]maintained by the GCC team. Last modified 19863 2021-07-28[16]. 19864 19865 References 19866 19867 1. http://gcc.gnu.org/gcc-2.95/regress.html 19868 2. http://gcc.gnu.org/gcc-2.95/othertest.html 19869 3. http://gcc.gnu.org/gcc-2.95/features.html 19870 4. http://gcc.gnu.org/gcc-2.95/buildstat.html 19871 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19872 6. http://gcc.gnu.org/gcc-2.95/caveats.html 19873 7. http://gcc.gnu.org/mirrors.html 19874 8. http://gcc.gnu.org/index.html 19875 9. mailto:gcc (a] gcc.gnu.org 19876 10. https://gcc.gnu.org/onlinedocs/ 19877 11. mailto:gcc-help (a] gcc.gnu.org 19878 12. mailto:gcc (a] gcc.gnu.org 19879 13. https://gcc.gnu.org/lists.html 19880 14. https://www.fsf.org/ 19881 15. https://gcc.gnu.org/about.html 19882 16. http://validator.w3.org/check/referer 19883 ====================================================================== 19884 http://gcc.gnu.org/gcc-2.95/features.html 19885 GCC 2.95 New Features 19886 19887 * General Optimizer Improvements: 19888 + [1]Localized register spilling to improve speed and code 19889 density especially on small register class machines. 19890 + [2]Global CSE using lazy code motion algorithms. 19891 + [3]Improved global constant/copy propagation. 19892 + [4]Improved control flow graph analysis and manipulation. 19893 + [5]Local dead store elimination. 19894 + [6]Memory Load hoisting/store sinking in loops. 19895 + [7]Type based alias analysis is enabled by default. Note this 19896 feature will expose bugs in the Linux kernel. Please refer to 19897 the FAQ (as shipped with GCC 2.95) for additional information 19898 on this issue. 19899 + Major revamp of GIV detection, combination and simplification 19900 to improve loop performance. 19901 + Major improvements to register allocation and reloading. 19902 * New Languages and Language specific improvements 19903 + [8]Many C++ improvements. 19904 + [9]Many Fortran improvements. 19905 + [10]Java front-end has been integrated. A [11]runtime library 19906 is available separately. 19907 + [12]ISO C99 support 19908 + [13]Chill front-end and runtime has been integrated. 19909 + Boehm garbage collector support in libobjc. 19910 + More support for various pragmas which appear in vendor 19911 include files 19912 * New Targets and Target Specific Improvements 19913 + [14]SPARC backend rewrite. 19914 + -mschedule=8000 will optimize code for PA8000 class 19915 processors; -mpa-risc-2-0 will generate code for PA2.0 19916 processors 19917 + Various micro-optimizations for the ia32 port. K6 19918 optimizations 19919 + Compiler will attempt to align doubles in the stack on the 19920 ia32 port 19921 + Alpha EV6 support 19922 + PowerPC 750 19923 + RS6000/PowerPC: -mcpu=401 was added as an alias for -mcpu=403. 19924 -mcpu=e603e was added to do -mcpu=603e and -msoft-float. 19925 + c3x, c4x 19926 + HyperSPARC 19927 + SparcLite86x 19928 + sh4 19929 + Support for new systems (OpenBSD, FreeBSD, UWIN, Interix, 19930 arm-linux) 19931 + vxWorks targets include support for vxWorks threads 19932 + StrongARM 110 and ARM9 support added. ARM Scheduling 19933 parameters rewritten. 19934 + Various changes to the MIPS port to avoid assembler macros, 19935 which in turn improves performance 19936 + Various performance improvements to the i960 port. 19937 + Major rewrite of ns32k port 19938 * Other significant improvements 19939 + [15]Ability to dump cfg information and display it using vcg. 19940 + The new faster scheme for fixing vendor header files is 19941 enabled by default. 19942 + Experimental internationalization support. 19943 + multibyte character support 19944 + Some compile-time speedups for pathological problems 19945 + Better support for complex types 19946 * Plus the usual mountain of bugfixes 19947 * Core compiler is based on the gcc2 development tree from Sept 30, 19948 1998, so we have all of the [16]features found in GCC 2.8. 19949 19950 Additional Changes in GCC 2.95.1 19951 19952 * Generic bugfixes and improvements 19953 + Various documentation fixes related to the GCC/EGCS merger. 19954 + Fix memory management bug which could lead to spurious aborts, 19955 core dumps or random parsing errors in the compiler. 19956 + Fix a couple bugs in the dwarf1 and dwarf2 debug record 19957 support. 19958 + Fix infinite loop in the CSE optimizer. 19959 + Avoid undefined behavior in compiler FP emulation code 19960 + Fix install problem when prefix is overridden on the make 19961 install command. 19962 + Fix problem with unwanted installation of assert.h on some 19963 systems. 19964 + Fix problem with finding the wrong assembler in a single tree 19965 build. 19966 + Avoid increasing the known alignment of a register that is 19967 already known to be a pointer. 19968 * Platform specific bugfixes and improvements 19969 + Codegen bugfix for prologue/epilogue for cpu32 target. 19970 + Fix long long code generation bug for the Coldfire target. 19971 + Fix various aborts in the SH compiler. 19972 + Fix bugs in libgcc support library for the SH. 19973 + Fix alpha ev6 code generation bug. 19974 + Fix problems with EXIT_SUCCESS/EXIT_FAILURE redefinitions on 19975 AIX platforms. 19976 + Fix -fpic code generation bug for rs6000/ppc svr4 targets. 19977 + Fix varargs/stdarg code generation bug for rs6000/ppc svr4 19978 targets. 19979 + Fix weak symbol handling for rs6000/ppc svr4 targets. 19980 + Fix various problems with 64bit code generation for the 19981 rs6000/ppc port. 19982 + Fix codegen bug which caused tetex to be mis-compiled on the 19983 x86. 19984 + Fix compiler abort in new cfg code exposed by x86 port. 19985 + Fix out of range array reference in code convert flat 19986 registers to the x87 stacked FP register file. 19987 + Fix minor vxworks configuration bug. 19988 + Fix return type of bsearch for SunOS 4.x. 19989 * Language & Runtime specific fixes. 19990 + The G++ signature extension has been deprecated. It will be 19991 removed in the next major release of G++. Use of signatures 19992 will result in a warning from the compiler. 19993 + Several bugs relating to templates and namespaces were fixed. 19994 + A bug that caused crashes when combining templates with -g on 19995 DWARF1 platforms was fixed. 19996 + Pointers-to-members, virtual functions, and multiple 19997 inheritance should now work together correctly. 19998 + Some code-generation bugs relating to function try blocks were 19999 fixed. 20000 + G++ is a little bit more lenient with certain archaic 20001 constructs than in GCC 2.95. 20002 + Fix to prevent shared library version #s from bring truncated 20003 to 1 digit 20004 + Fix missing std:: in the libstdc++ library. 20005 + Fix stream locking problems in libio. 20006 + Fix problem in java compiler driver. 20007 20008 Additional Changes in GCC 2.95.2 20009 20010 The -fstrict-aliasing is not enabled by default for GCC 2.95.2. While 20011 the optimizations performed by -fstrict-aliasing are valid according to 20012 the C and C++ standards, the optimization have caused some problems, 20013 particularly with old non-conforming code. 20014 20015 The GCC developers are experimenting with ways to warn users about code 20016 which violates the C/C++ standards, but those warnings are not ready 20017 for widespread use at this time. Rather than wait for those warnings 20018 the GCC developers have chosen to disable -fstrict-aliasing by default 20019 for the GCC 2.95.2 release. 20020 20021 We strongly encourage developers to find and fix code which violates 20022 the C/C++ standards as -fstrict-aliasing may be enabled by default in 20023 future releases. Use the option -fstrict-aliasing to re-enable these 20024 optimizations. 20025 * Generic bugfixes and improvements 20026 + Fix incorrectly optimized memory reference in global common 20027 subexpression elimination (GCSE) optimization pass. 20028 + Fix code generation bug in regmove.c in which it could 20029 incorrectly change a "const" value. 20030 + Fix bug in optimization of conditionals involving volatile 20031 memory references. 20032 + Avoid over-allocation of stack space for some procedures. 20033 + Fixed bug in the compiler which caused incorrect optimization 20034 of an obscure series of bit manipulations, shifts and 20035 arithmetic. 20036 + Fixed register allocator bug which caused teTeX to be 20037 mis-compiled on SPARC targets. 20038 + Avoid incorrect optimization of degenerate case statements for 20039 certain targets such as the ARM. 20040 + Fix out of range memory reference in the jump optimizer. 20041 + Avoid dereferencing null pointer in fix-header. 20042 + Fix test for GCC specific features so that it is possible to 20043 bootstrap with gcc-2.6.2 and older versions of GCC. 20044 + Fix typo in scheduler which could potentially cause out of 20045 range memory accesses. 20046 + Avoid incorrect loop reversal which caused incorrect code for 20047 certain loops on PowerPC targets. 20048 + Avoid incorrect optimization of switch statements on certain 20049 targets (for example the ARM). 20050 * Platform specific bugfixes and improvements 20051 + Work around bug in Sun V5.0 compilers which caused bootstrap 20052 comparison failures on SPARC targets. 20053 + Fix SPARC backend bug which caused aborts in final.c. 20054 + Fix sparc-hal-solaris2* configuration fragments. 20055 + Fix bug in sparc block profiling. 20056 + Fix obscure code generation bug for the PARISC targets. 20057 + Define __STDC_EXT__ for HPUX configurations. 20058 + Various POWERPC64 code generation bugfixes. 20059 + Fix abort for PPC targets using ELF (ex GNU/Linux). 20060 + Fix collect2 problems for AIX targets. 20061 + Correct handling of .file directive for PPC targets. 20062 + Fix bug in fix_trunc x86 patterns. 20063 + Fix x86 port to correctly pop the FP stack for functions that 20064 return structures in memory. 20065 + Fix minor bug in strlen x86 pattern. 20066 + Use stabs debugging instead of dwarf1 for x86-solaris targets. 20067 + Fix template repository code to handle leading underscore in 20068 mangled names. 20069 + Fix weak/weak alias support for OpenBSD. 20070 + GNU/Linux for the ARM has C++ compatible include files. 20071 * Language & Runtime specific fixes. 20072 + Fix handling of constructor attribute in the C front-end which 20073 caused problems building the Chill runtime library on some 20074 targets. 20075 + Fix minor problem merging type qualifiers in the C front-end. 20076 + Fix aliasing bug for pointers and references (C/C++). 20077 + Fix incorrect "non-constant initializer bug" when -traditional 20078 or -fwritable-strings is enabled. 20079 + Fix build error for Chill front-end on SunOS. 20080 + Do not complain about duplicate instantiations when using 20081 -frepo (C++). 20082 + Fix array bounds handling in C++ front-end which caused 20083 problems with dwarf debugging information in some 20084 circumstances. 20085 + Fix minor namespace problem. 20086 + Fix problem linking java programs. 20087 20088 Additional Changes in GCC 2.95.3 20089 20090 * Generic bugfixes and improvements 20091 + Fix numerous problems that caused incorrect optimization in 20092 the register reloading code. 20093 + Fix numerous problems that caused incorrect optimization in 20094 the loop optimizer. 20095 + Fix aborts in the functions build_insn_chain and scan_loops 20096 under some circumstances. 20097 + Fix an alias analysis bug. 20098 + Fix an infinite compilation bug in the combiner. 20099 + A few problems with complex number support have been fixed. 20100 + It is no longer possible for gcc to act as a fork bomb when 20101 installed incorrectly. 20102 + The -fpack-struct option should be recognized now. 20103 + Fixed a bug that caused incorrect code to be generated due to 20104 a lost stack adjustment. 20105 * Platform specific bugfixes and improvements 20106 + Support building ARM toolchains hosted on Windows. 20107 + Fix attribute calculations in ARM toolchains. 20108 + arm-linux support has been improved. 20109 + Fix a PIC failure on sparc targets. 20110 + On ix86 targets, the regparm attribute should now work 20111 reliably. 20112 + Several updates for the h8300 port. 20113 + Fix problem building libio with glibc 2.2. 20114 20115 20116 For questions related to the use of GCC, please consult these web 20117 pages and the [17]GCC manuals. If that fails, the 20118 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20119 web pages and the development of GCC are welcome on our developer 20120 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 20121 archives. 20122 20123 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 20124 distribution of this entire article is permitted in any medium, 20125 provided this notice is preserved. 20126 20127 These pages are [22]maintained by the GCC team. Last modified 20128 2021-07-28[23]. 20129 20130 References 20131 20132 1. http://gcc.gnu.org/news/spill.html 20133 2. http://gcc.gnu.org/news/lcm.html 20134 3. http://gcc.gnu.org/news/cprop.html 20135 4. http://gcc.gnu.org/news/cfg.html 20136 5. http://gcc.gnu.org/news/dse.html 20137 6. http://gcc.gnu.org/news/hoist.html 20138 7. http://gcc.gnu.org/news/alias.html 20139 8. http://gcc.gnu.org/gcc-2.95/c++features.html 20140 9. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 20141 10. http://gcc.gnu.org/news/gcj-announce.txt 20142 11. http://gcc.gnu.org/news/javaannounce.html 20143 12. http://gcc.gnu.org/c99status.html 20144 13. http://gcc.gnu.org/news/chill.html 20145 14. http://gcc.gnu.org/news/sparc.html 20146 15. http://gcc.gnu.org/news/egcs-vcg.html 20147 16. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20148 17. https://gcc.gnu.org/onlinedocs/ 20149 18. mailto:gcc-help (a] gcc.gnu.org 20150 19. mailto:gcc (a] gcc.gnu.org 20151 20. https://gcc.gnu.org/lists.html 20152 21. https://www.fsf.org/ 20153 22. https://gcc.gnu.org/about.html 20154 23. http://validator.w3.org/check/referer 20155 ====================================================================== 20156 http://gcc.gnu.org/gcc-2.95/caveats.html 20157 GCC 2.95 Caveats 20158 20159 * GCC 2.95 will issue an error for invalid asm statements that had 20160 been silently accepted by earlier versions of the compiler. This is 20161 particularly noticeable when compiling older versions of the Linux 20162 kernel (2.0.xx). Please refer to the FAQ (as shipped with GCC 2.95) 20163 for more information on this issue. 20164 * GCC 2.95 implements type based alias analysis to disambiguate 20165 memory references. Some programs, particularly the Linux kernel 20166 violate ANSI/ISO aliasing rules and therefore may not operate 20167 correctly when compiled with GCC 2.95. Please refer to the FAQ (as 20168 shipped with GCC 2.95) for more information on this issue. 20169 * GCC 2.95 has a known bug in its handling of complex variables for 20170 64bit targets. Instead of silently generating incorrect code, GCC 20171 2.95 will issue a fatal error for situations it can not handle. 20172 This primarily affects the Fortran community as Fortran makes more 20173 use of complex variables than C or C++. 20174 * GCC 2.95 has an integrated libstdc++, but does not have an 20175 integrated libg++. Furthermore old libg++ releases will not work 20176 with GCC 2.95. You can retrieve a recent copy of libg++ from the 20177 [1]GCC ftp server. 20178 Note most C++ programs only need libstdc++. 20179 * Exception handling may not work with shared libraries, particularly 20180 on alphas, hppas, rs6000/powerpc and mips based platforms. 20181 Exception handling is known to work on x86 GNU/Linux platforms with 20182 shared libraries. 20183 * In general, GCC 2.95 is more rigorous about rejecting invalid C++ 20184 code or deprecated C++ constructs than G++ 2.7, G++ 2.8, EGCS 1.0, 20185 or EGCS 1.1. As a result it may be necessary to fix C++ code before 20186 it will compile with GCC 2.95. 20187 * G++ is also converting toward the ISO C++ standard; as a result 20188 code which was previously valid (and thus accepted by other 20189 compilers and older versions of g++) may no longer be accepted. The 20190 flag -fpermissive may allow some non-conforming code to compile 20191 with GCC 2.95. 20192 * GCC 2.95 compiled C++ code is not binary compatible with EGCS 20193 1.1.x, EGCS 1.0.x or GCC 2.8.x. 20194 * GCC 2.95 does not have changes from the GCC 2.8 tree that were made 20195 between Sept 30, 1998 and April 30, 1999 (the official end of the 20196 GCC 2.8 project). Future GCC releases will include all the changes 20197 from the defunct GCC 2.8 sources. 20198 20199 20200 For questions related to the use of GCC, please consult these web 20201 pages and the [2]GCC manuals. If that fails, the 20202 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20203 web pages and the development of GCC are welcome on our developer 20204 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 20205 20206 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 20207 distribution of this entire article is permitted in any medium, 20208 provided this notice is preserved. 20209 20210 These pages are [7]maintained by the GCC team. Last modified 20211 2021-07-28[8]. 20212 20213 References 20214 20215 1. ftp://gcc.gnu.org/pub/gcc/infrastructure/libg++-2.8.1.3.tar.gz 20216 2. https://gcc.gnu.org/onlinedocs/ 20217 3. mailto:gcc-help (a] gcc.gnu.org 20218 4. mailto:gcc (a] gcc.gnu.org 20219 5. https://gcc.gnu.org/lists.html 20220 6. https://www.fsf.org/ 20221 7. https://gcc.gnu.org/about.html 20222 8. http://validator.w3.org/check/referer 20223 ====================================================================== 20224 http://gcc.gnu.org/egcs-1.1/index.html 20225 EGCS 1.1 20226 20227 September 3, 1998: We are pleased to announce the release of EGCS 1.1. 20228 December 1, 1998: We are pleased to announce the release of EGCS 1.1.1. 20229 March 15, 1999: We are pleased to announce the release of EGCS 1.1.2. 20230 20231 EGCS is a free software project to further the development of the GNU 20232 compilers using an open development environment. 20233 20234 EGCS 1.1 is a major new release of the EGCS compiler system. It has 20235 been [1]extensively tested and is believed to be stable and suitable 20236 for widespread use. 20237 20238 EGCS 1.1 is based on an June 6, 1998 snapshot of the GCC 2.8 20239 development sources; it contains all of the new features found in GCC 20240 2.8.1 as well as all new development from GCC up to June 6, 1998. 20241 20242 EGCS 1.1 also contains many improvements and features not found in GCC 20243 or in older versions of EGCS: 20244 * Global common subexpression elimination and global constant/copy 20245 propagation (aka [2]gcse) 20246 * Ongoing improvements to the [3]alias analysis support to allow for 20247 better optimizations throughout the compiler. 20248 * Vastly improved [4]C++ compiler and integrated C++ runtime 20249 libraries. 20250 * Fixes for the /tmp symlink race security problems. 20251 * New targets including mips16, arm-thumb and 64 bit PowerPC. 20252 * Improvements to GNU Fortran (g77) compiler and runtime library made 20253 since g77 version 0.5.23. 20254 20255 See the [5]new features page for a more complete list of new features 20256 found in EGCS 1.1 releases. 20257 20258 EGCS 1.1.1 is a minor update to fix several serious problems in EGCS 20259 1.1: 20260 * General improvements and fixes 20261 + Avoid some stack overflows when compiling large functions. 20262 + Avoid incorrect loop invariant code motions. 20263 + Fix some core dumps on Linux kernel code. 20264 + Bring back the imake -Di386 and friends fix from EGCS 1.0.2. 20265 + Fix code generation problem in gcse. 20266 + Various documentation related fixes. 20267 * g++/libstdc++ improvements and fixes 20268 + MT safe EH fix for setjmp/longjmp based exception handling. 20269 + Fix a few bad interactions between optimization and exception 20270 handling. 20271 + Fixes for demangling of template names starting with "__". 20272 + Fix a bug that would fail to run destructors in some cases 20273 with -O2. 20274 + Fix 'new' of classes with virtual bases. 20275 + Fix crash building Qt on the Alpha. 20276 + Fix failure compiling WIFEXITED macro on GNU/Linux. 20277 + Fix some -frepo failures. 20278 * g77 and libf2c improvements and fixes 20279 + Various documentation fixes. 20280 + Avoid compiler crash on RAND intrinsic. 20281 + Fix minor bugs in makefiles exposed by BSD make programs. 20282 + Define _XOPEN_SOURCE for libI77 build to avoid potential 20283 problems on some 64-bit systems. 20284 + Fix problem with implicit endfile on rewind. 20285 + Fix spurious recursive I/O errors. 20286 * platform specific improvements and fixes 20287 + Match all versions of UnixWare7. 20288 + Do not assume x86 SVR4 or UnixWare targets can handle stabs. 20289 + Fix PPC/RS6000 LEGITIMIZE_ADDRESS macro and bug in conversion 20290 from unsigned ints to double precision floats. 20291 + Fix ARM ABI issue with NetBSD. 20292 + Fix a few arm code generation bugs. 20293 + Fixincludes will fix additional broken SCO OpenServer header 20294 files. 20295 + Fix a m68k backend bug which caused invalid offsets in reg+d 20296 addresses. 20297 + Fix problems with 64bit AIX 4.3 support. 20298 + Fix handling of long longs for varargs/stdarg functions on the 20299 ppc. 20300 + Minor fixes to CPP predefines for Windows. 20301 + Fix code generation problems with gpr<->fpr copies for 64bit 20302 ppc. 20303 + Fix a few coldfire code generation bugs. 20304 + Fix some more header file problems on SunOS 4.x. 20305 + Fix assert.h handling for RTEMS. 20306 + Fix Windows handling of TREE_SYMBOL_REFERENCED. 20307 + Fix x86 compiler abort in reg-stack pass. 20308 + Fix cygwin/windows problem with section attributes. 20309 + Fix Alpha code generation problem exposed by SMP Linux 20310 kernels. 20311 + Fix typo in m68k 32->64bit integer conversion. 20312 + Make sure target libraries build with -fPIC for PPC & Alpha 20313 targets. 20314 20315 EGCS 1.1.2 is a minor update to fix several serious problems in EGCS 20316 1.1.1: 20317 * General improvements and fixes 20318 + Fix bug in loop optimizer which caused the SPARC (and 20319 potentially other) ports to segfault. 20320 + Fix infinite recursion in alias analysis and combiner code. 20321 + Fix bug in regclass preferencing. 20322 + Fix incorrect loop reversal which caused incorrect code to be 20323 generated for several targets. 20324 + Fix return value for builtin memcpy. 20325 + Reduce compile time for certain loops which exposed quadratic 20326 behavior in the loop optimizer. 20327 + Fix bug which caused volatile memory to be written multiple 20328 times when only one write was needed/desired. 20329 + Fix compiler abort in caller-save.c 20330 + Fix combiner bug which caused incorrect code generation for 20331 certain division by constant operations. 20332 + Fix incorrect code generation due to a bug in range check 20333 optimizations. 20334 + Fix incorrect code generation due to mis-handling of clobbered 20335 values in CSE. 20336 + Fix compiler abort/segfault due to incorrect register 20337 splitting when unrolling loops. 20338 + Fix code generation involving autoincremented addresses with 20339 ternary operators. 20340 + Work around bug in the scheduler which caused qt to be 20341 mis-compiled on some platforms. 20342 + Fix code generation problems with -fshort-enums. 20343 + Tighten security for temporary files. 20344 + Improve compile time for codes which make heavy use of 20345 overloaded functions. 20346 + Fix multiply defined constructor/destructor symbol problems. 20347 + Avoid setting bogus RPATH environment variable during 20348 bootstrap. 20349 + Avoid GNU-make dependencies in the texinfo subdir. 20350 + Install CPP wrapper script in $(prefix)/bin if --enable-cpp. 20351 --enable-cpp=<dirname> can be used to specify an additional 20352 install directory for the cpp wrapper script. 20353 + Fix CSE bug which caused incorrect label-label refs to appear 20354 on some platforms. 20355 + Avoid linking in EH routines from libgcc if they are not 20356 needed. 20357 + Avoid obscure bug in aliasing code. 20358 + Fix bug in weak symbol handling. 20359 * Platform-specific improvements and fixes 20360 + Fix detection of PPro/PII on Unixware 7. 20361 + Fix compiler segfault when building spec99 and other programs 20362 for SPARC targets. 20363 + Fix code-generation bugs for integer and floating point 20364 conditional move instructions on the PPro/PII. 20365 + Use fixincludes to fix byteorder problems on i?86-*-sysv. 20366 + Fix build failure for the arc port. 20367 + Fix floating point format configuration for i?86-gnu port. 20368 + Fix problems with hppa1.0-hp-hpux10.20 configuration when 20369 threads are enabled. 20370 + Fix coldfire code generation bugs. 20371 + Fix "unrecognized insn" problems for Alpha and PPC ports. 20372 + Fix h8/300 code generation problem with floating point values 20373 in memory. 20374 + Fix unrecognized insn problems for the m68k port. 20375 + Fix namespace-pollution problem for the x86 port. 20376 + Fix problems with old assembler on x86 NeXT systems. 20377 + Fix PIC code-generation problems for the SPARC port. 20378 + Fix minor bug with LONG_CALLS in PowerPC SVR4 support. 20379 + Fix minor ISO namespace violation in Alpha varargs/stdarg 20380 support. 20381 + Fix incorrect "braf" instruction usage for the SH port. 20382 + Fix minor bug in va-sh which prevented its use with -ansi. 20383 + Fix problems recognizing and supporting FreeBSD. 20384 + Handle OpenBSD systems correctly. 20385 + Minor fixincludes fix for Digital UNIX 4.0B. 20386 + Fix problems with ctors/dtors in SCO shared libraries. 20387 + Abort instead of generating incorrect code for PPro/PII 20388 floating point conditional moves. 20389 + Avoid multiply defined symbols on GNU/Linux systems using 20390 libc-5.4.xx. 20391 + Fix abort in alpha compiler. 20392 * Fortran-specific fixes 20393 + Fix the IDate intrinsic (VXT) (in libg2c) so the returned year 20394 is in the documented, non-Y2K-compliant range of 0-99, instead 20395 of being returned as 100 in the year 2000. 20396 + Fix the `Date_and_Time' intrinsic (in libg2c) to return the 20397 milliseconds value properly in Values(8). 20398 + Fix the `LStat' intrinsic (in libg2c) to return device-ID 20399 information properly in SArray(7). 20400 20401 Each release includes installation instructions in both HTML and 20402 plaintext forms (see the INSTALL directory in the toplevel directory of 20403 the distribution). However, we also keep the most up to date 20404 installation instructions and [6]build/test status on our web page. We 20405 will update those pages as new information becomes available. 20406 20407 The EGCS project would like to thank the numerous people that have 20408 contributed new features, test results, bugfixes, etc. This [7]amazing 20409 group of volunteers is what makes EGCS successful. 20410 20411 And finally, we can't in good conscience fail to mention some 20412 [8]caveats to using EGCS 1.1. 20413 20414 Download EGCS from egcs.cygnus.com (USA California). 20415 20416 The EGCS 1.1 release is also available on many mirror sites. 20417 [9]Goto mirror list to find a closer site. 20418 20419 20420 For questions related to the use of GCC, please consult these web 20421 pages and the [10]GCC manuals. If that fails, the 20422 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20423 web pages and the development of GCC are welcome on our developer 20424 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 20425 archives. 20426 20427 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 20428 distribution of this entire article is permitted in any medium, 20429 provided this notice is preserved. 20430 20431 These pages are [15]maintained by the GCC team. Last modified 20432 2021-07-28[16]. 20433 20434 References 20435 20436 1. http://gcc.gnu.org/egcs-1.1/egcs-1.1-test.html 20437 2. http://gcc.gnu.org/news/gcse.html 20438 3. http://gcc.gnu.org/news/alias.html 20439 4. http://gcc.gnu.org/egcs-1.1/c++features.html 20440 5. http://gcc.gnu.org/egcs-1.1/features.html 20441 6. http://gcc.gnu.org/egcs-1.1/buildstat.html 20442 7. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 20443 8. http://gcc.gnu.org/egcs-1.1/caveats.html 20444 9. http://gcc.gnu.org/mirrors.html 20445 10. https://gcc.gnu.org/onlinedocs/ 20446 11. mailto:gcc-help (a] gcc.gnu.org 20447 12. mailto:gcc (a] gcc.gnu.org 20448 13. https://gcc.gnu.org/lists.html 20449 14. https://www.fsf.org/ 20450 15. https://gcc.gnu.org/about.html 20451 16. http://validator.w3.org/check/referer 20452 ====================================================================== 20453 http://gcc.gnu.org/egcs-1.1/features.html 20454 EGCS 1.1 new features 20455 20456 * Integrated GNU Fortran (g77) compiler and runtime library with 20457 improvements, based on g77 version 0.5.23. 20458 * Vast improvements in the C++ compiler; so many they have [1]page of 20459 their own! 20460 * Compiler implements [2]global common subexpression elimination and 20461 global copy/constant propagation. 20462 * More major improvements in the [3]alias analysis code. 20463 * More major improvements in the exception handling code to improve 20464 performance, lower static overhead and provide the infrastructure 20465 for future improvements. 20466 * The infamous /tmp symlink race security problems have been fixed. 20467 * The regmove optimization pass has been nearly completely rewritten 20468 to improve performance of generated code. 20469 * The compiler now recomputes register usage information before local 20470 register allocation. By providing more accurate information to the 20471 priority based allocator, we get better register allocation. 20472 * The register reloading phase of the compiler optimizes spill code 20473 much better than in previous releases. 20474 * Some bad interactions between the register allocator and 20475 instruction scheduler have been fixed, resulting in much better 20476 code for certain programs. Additionally, we have tuned the 20477 scheduler in various ways to improve performance of generated code 20478 for some architectures. 20479 * The compiler's branch shortening algorithms have been significantly 20480 improved to work better on targets which align jump targets. 20481 * The compiler now supports -Os to prefer optimizing for code space 20482 over optimizing for code speed. 20483 * The compiler will now totally eliminate library calls which compute 20484 constant values. This primarily helps targets with no integer 20485 div/mul support and targets without floating point support. 20486 * The compiler now supports an extensive "--help" option. 20487 * cpplib has been greatly improved and may be suitable for limited 20488 use. 20489 * Memory footprint for the compiler has been significantly reduced 20490 for some pathological cases. 20491 * The time to build EGCS has been improved for certain targets 20492 (particularly the alpha and mips platforms). 20493 * Many infrastructure improvements throughout the compiler, plus the 20494 usual mountain of bugfixes and minor improvements. 20495 * Target dependent improvements: 20496 + SPARC port now includes V8 plus and V9 support as well as 20497 performance tuning for Ultra class machines. The SPARC port 20498 now uses the Haifa scheduler. 20499 + Alpha port has been tuned for the EV6 processor and has an 20500 optimized expansion of memcpy/bzero. The Alpha port now uses 20501 the Haifa scheduler. 20502 + RS6000/PowerPC: support for the Power64 architecture and AIX 20503 4.3. The RS6000/PowerPC port now uses the Haifa scheduler. 20504 + x86: Alignment of static store data and jump targets is per 20505 Intel recommendations now. Various improvements throughout the 20506 x86 port to improve performance on Pentium processors 20507 (including improved epilogue sequences for Pentium chips and 20508 backend improvements which should help register allocation on 20509 all x86 variants. Conditional move support has been fixed and 20510 enabled for PPro processors. The x86 port also better supports 20511 64bit operations now. Unixware 7, a System V Release 5 target, 20512 is now supported and SCO OpenServer targets can support GAS. 20513 + MIPS has improved multiply/multiply-add support and now 20514 includes mips16 ISA support. 20515 + M68k has many micro-optimizations and Coldfire fixes. 20516 * Core compiler is based on the GCC development tree from June 9, 20517 1998, so we have all of the [4]features found in GCC 2.8. 20518 20519 20520 For questions related to the use of GCC, please consult these web 20521 pages and the [5]GCC manuals. If that fails, the 20522 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20523 web pages and the development of GCC are welcome on our developer 20524 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 20525 20526 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 20527 distribution of this entire article is permitted in any medium, 20528 provided this notice is preserved. 20529 20530 These pages are [10]maintained by the GCC team. Last modified 20531 2021-07-28[11]. 20532 20533 References 20534 20535 1. http://gcc.gnu.org/egcs-1.1/c++features.html 20536 2. http://gcc.gnu.org/news/gcse.html 20537 3. http://gcc.gnu.org/news/alias.html 20538 4. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20539 5. https://gcc.gnu.org/onlinedocs/ 20540 6. mailto:gcc-help (a] gcc.gnu.org 20541 7. mailto:gcc (a] gcc.gnu.org 20542 8. https://gcc.gnu.org/lists.html 20543 9. https://www.fsf.org/ 20544 10. https://gcc.gnu.org/about.html 20545 11. http://validator.w3.org/check/referer 20546 ====================================================================== 20547 http://gcc.gnu.org/egcs-1.1/caveats.html 20548 EGCS 1.1 Caveats 20549 20550 * EGCS has an integrated libstdc++, but does not have an integrated 20551 libg++. Furthermore old libg++ releases will not work with EGCS; HJ 20552 Lu has made a libg++-2.8.1.2 snapshot available which may work with 20553 EGCS. 20554 Note most C++ programs only need libstdc++. 20555 * Exception handling may not work with shared libraries, particularly 20556 on alphas, hppas, rs6000/powerpc and mips based platforms. 20557 Exception handling is known to work on x86-linux platforms with 20558 shared libraries. 20559 * Some versions of the Linux kernel have bugs which prevent them from 20560 being compiled or from running when compiled by EGCS. See the FAQ 20561 (as shipped with EGCS 1.1) for additional information. 20562 * In general, EGCS is more rigorous about rejecting invalid C++ code 20563 or deprecated C++ constructs than g++-2.7, g++-2.8 or EGCS 1.0. As 20564 a result it may be necessary to fix C++ code before it will compile 20565 with EGCS. 20566 * G++ is also converting toward the ISO C++ standard; as a result 20567 code which was previously valid (and thus accepted by other 20568 compilers and older versions of g++) may no longer be accepted. 20569 * EGCS 1.1 compiled C++ code is not binary compatible with EGCS 1.0.x 20570 or GCC 2.8.x due to changes necessary to support thread safe 20571 exception handling. 20572 20573 20574 For questions related to the use of GCC, please consult these web 20575 pages and the [1]GCC manuals. If that fails, the 20576 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20577 web pages and the development of GCC are welcome on our developer 20578 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 20579 20580 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 20581 distribution of this entire article is permitted in any medium, 20582 provided this notice is preserved. 20583 20584 These pages are [6]maintained by the GCC team. Last modified 20585 2021-07-28[7]. 20586 20587 References 20588 20589 1. https://gcc.gnu.org/onlinedocs/ 20590 2. mailto:gcc-help (a] gcc.gnu.org 20591 3. mailto:gcc (a] gcc.gnu.org 20592 4. https://gcc.gnu.org/lists.html 20593 5. https://www.fsf.org/ 20594 6. https://gcc.gnu.org/about.html 20595 7. http://validator.w3.org/check/referer 20596 ====================================================================== 20597 http://gcc.gnu.org/egcs-1.0/index.html 20598 EGCS 1.0 20599 20600 December 3, 1997: We are pleased to announce the release of EGCS 1.0. 20601 January 6, 1998: We are pleased to announce the release of EGCS 1.0.1. 20602 March 16, 1998: We are pleased to announce the release of EGCS 1.0.2. 20603 May 15, 1998 We are pleased to announce the release of EGCS 1.0.3. 20604 20605 EGCS is a collaborative effort involving several groups of hackers 20606 using an open development model to accelerate development and testing 20607 of GNU compilers and runtime libraries. 20608 20609 An important goal of EGCS is to allow wide scale testing of 20610 experimental features and optimizations; therefore, EGCS contains some 20611 features and optimizations which are still under development. However, 20612 EGCS has been carefully tested and should be comparable in quality to 20613 most GCC releases. 20614 20615 EGCS 1.0 is based on an August 2, 1997 snapshot of the GCC 2.8 20616 development sources; it contains nearly all of the new features found 20617 in GCC 2.8. 20618 20619 EGCS 1.0 also contains many improvements and features not found in GCC 20620 2.7 and even the GCC 2.8 series (which was released after the original 20621 EGCS 1.0 release). 20622 * Integrated C++ runtime libraries, including support for most major 20623 GNU/Linux systems! 20624 * The integrated libstdc++ library includes a verbatim copy of SGI's 20625 STL release. 20626 * Integrated GNU Fortran compiler. 20627 * New instruction scheduler. 20628 * New alias analysis code. 20629 20630 See the [1]new features page for a more complete list of new features. 20631 20632 EGCS 1.0.1 is a minor update to the EGCS 1.0 compiler to fix a few 20633 critical bugs and add support for Red Hat 5.0 Linux. Changes since the 20634 EGCS 1.0 release: 20635 * Add support for Red Hat 5.0 Linux and better support for Linux 20636 systems using glibc2. 20637 Many programs failed to link when compiled with EGCS 1.0 on Red Hat 20638 5.0 or on systems with newer versions of glibc2. EGCS 1.0.1 should 20639 fix these problems. 20640 * Compatibility with both EGCS 1.0 and GCC 2.8 libgcc exception 20641 handling interfaces. 20642 To avoid future compatibility problems, we strongly urge anyone who 20643 is planning on distributing shared libraries that contain C++ code 20644 to upgrade to EGCS 1.0.1 first. 20645 Soon after EGCS 1.0 was released, the GCC developers made some 20646 incompatible changes in libgcc's exception handling interfaces. 20647 These changes were needed to solve problems on some platforms. This 20648 means that GCC 2.8.0, when released, will not be seamlessly 20649 compatible with shared libraries built by EGCS 1.0. The reason is 20650 that the libgcc.a in GCC 2.8.0 will not contain a function needed 20651 by the old interface. 20652 The result of this is that there may be compatibility problems with 20653 shared libraries built by EGCS 1.0 when used with GCC 2.8.0. 20654 With EGCS 1.0.1, generated code uses the new (GCC 2.8.0) interface, 20655 and libgcc.a has the support routines for both the old and the new 20656 interfaces (so EGCS 1.0.1 and EGCS 1.0 code can be freely mixed, 20657 and EGCS 1.0.1 and GCC 2.8.0 code can be freely mixed). 20658 The maintainers of GCC 2.x have decided against including seamless 20659 support for the old interface in 2.8.0, since it was never 20660 "official", so to avoid future compatibility problems we recommend 20661 against distributing any shared libraries built by EGCS 1.0 that 20662 contain C++ code (upgrade to 1.0.1 and use that). 20663 * Various bugfixes in the x86, hppa, mips, and rs6000/ppc back ends. 20664 The x86 changes fix code generation errors exposed when building 20665 glibc2 and the usual GNU/Linux dynamic linker (ld.so). 20666 The hppa change fixes a compiler abort when configured for use with 20667 RTEMS. 20668 The MIPS changes fix problems with the definition of LONG_MAX on 20669 newer systems, allow for command line selection of the target ABI, 20670 and fix one code generation problem. 20671 The rs6000/ppc change fixes some problems with passing structures 20672 to varargs/stdarg functions. 20673 * A few machine independent bugfixes, mostly to fix code generation 20674 errors when building Linux kernels or glibc. 20675 * Fix a few critical exception handling and template bugs in the C++ 20676 compiler. 20677 * Fix Fortran namelist bug on alphas. 20678 * Fix build problems on x86-solaris systems. 20679 20680 EGCS 1.0.2 is a minor update to the EGCS 1.0.1 compiler to fix several 20681 serious problems in EGCS 1.0.1. 20682 * General improvements and fixes 20683 + Memory consumption significantly reduced, especially for 20684 templates and inline functions. 20685 + Fix various problems with glibc2.1. 20686 + Fix loop optimization bug exposed by rs6000/ppc port. 20687 + Fix to avoid potential code generation problems in jump.c. 20688 + Fix some undefined symbol problems in dwarf1 debug support. 20689 * g++/libstdc++ improvements and fixes 20690 + libstdc++ in the EGCS release has been updated and should be 20691 link compatible with libstdc++-2.8. 20692 + Various fixes in libio/libstdc++ to work better on GNU/Linux 20693 systems. 20694 + Fix problems with duplicate symbols on systems that do not 20695 support weak symbols. 20696 + Memory corruption bug and undefined symbols in bastring have 20697 been fixed. 20698 + Various exception handling fixes. 20699 + Fix compiler abort for very long thunk names. 20700 * g77 improvements and fixes 20701 + Fix compiler crash for omitted bound in Fortran CASE 20702 statement. 20703 + Add missing entries to g77 lang-options. 20704 + Fix problem with -fpedantic in the g77 compiler. 20705 + Fix "backspace" problem with g77 on alphas. 20706 + Fix x86 backend problem with Fortran literals and -fpic. 20707 + Fix some of the problems with negative subscripts for g77 on 20708 alphas. 20709 + Fixes for Fortran builds on cygwin32/mingw32. 20710 * platform specific improvements and fixes 20711 + Fix long double problems on x86 (exposed by glibc). 20712 + x86 ports define i386 again to keep imake happy. 20713 + Fix exception handling support on NetBSD ports. 20714 + Several changes to collect2 to fix many problems with AIX. 20715 + Define __ELF__ for GNU/Linux on rs6000. 20716 + Fix -mcall-linux problem on GNU/Linux on rs6000. 20717 + Fix stdarg/vararg problem for GNU/Linux on rs6000. 20718 + Allow autoconf to select a proper install problem on AIX 3.1. 20719 + m68k port support includes -mcpu32 option as well as cpu32 20720 multilibs. 20721 + Fix stdarg bug for irix6. 20722 + Allow EGCS to build on irix5 without the gnu assembler. 20723 + Fix problem with static linking on sco5. 20724 + Fix bootstrap on sco5 with native compiler. 20725 + Fix for abort building newlib on H8 target. 20726 + Fix fixincludes handling of math.h on SunOS. 20727 + Minor fix for Motorola 3300 m68k systems. 20728 20729 EGCS 1.0.3 is a minor update to the EGCS 1.0.2 compiler to fix a few 20730 problems reported by Red Hat for builds of Red Hat 5.1. 20731 * Generic bugfixes: 20732 + Fix a typo in the libio library which resulted in incorrect 20733 behavior of istream::get. 20734 + Fix the Fortran negative array index problem. 20735 + Fix a major problem with the ObjC runtime thread support 20736 exposed by glibc2. 20737 + Reduce memory consumption of the Haifa scheduler. 20738 * Target specific bugfixes: 20739 + Fix one x86 floating point code generation bug exposed by 20740 glibc2 builds. 20741 + Fix one x86 internal compiler error exposed by glibc2 builds. 20742 + Fix profiling bugs on the Alpha. 20743 + Fix ImageMagick & emacs 20.2 build problems on the Alpha. 20744 + Fix rs6000/ppc bug when converting values from integer types 20745 to floating point types. 20746 20747 The EGCS 1.0 releases include installation instructions in both HTML 20748 and plaintext forms (see the INSTALL directory in the toplevel 20749 directory of the distribution). However, we also keep the most up to 20750 date installation instructions and [2]build/test status on our web 20751 page. We will update those pages as new information becomes available. 20752 20753 And, we can't in good conscience fail to mention some [3]caveats to 20754 using EGCS. 20755 20756 Update: Big thanks to Stanford for providing a high speed link for 20757 downloading EGCS (go.cygnus.com)! 20758 20759 Download EGCS from ftp.cygnus.com (USA California) or go.cygnus.com 20760 (USA California -- High speed link provided by Stanford). 20761 20762 The EGCS 1.0 release is also available many mirror sites. 20763 [4]Goto mirror list to find a closer site 20764 20765 We'd like to thank the numerous people that have contributed new 20766 features, test results, bugfixes, etc. Unfortunately, they're far too 20767 numerous to mention by name. 20768 20769 20770 For questions related to the use of GCC, please consult these web 20771 pages and the [5]GCC manuals. If that fails, the 20772 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20773 web pages and the development of GCC are welcome on our developer 20774 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 20775 20776 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 20777 distribution of this entire article is permitted in any medium, 20778 provided this notice is preserved. 20779 20780 These pages are [10]maintained by the GCC team. Last modified 20781 2021-07-28[11]. 20782 20783 References 20784 20785 1. http://gcc.gnu.org/egcs-1.0/features.html 20786 2. http://gcc.gnu.org/egcs-1.0/buildstat.html 20787 3. http://gcc.gnu.org/egcs-1.0/caveats.html 20788 4. http://gcc.gnu.org/mirrors.html 20789 5. https://gcc.gnu.org/onlinedocs/ 20790 6. mailto:gcc-help (a] gcc.gnu.org 20791 7. mailto:gcc (a] gcc.gnu.org 20792 8. https://gcc.gnu.org/lists.html 20793 9. https://www.fsf.org/ 20794 10. https://gcc.gnu.org/about.html 20795 11. http://validator.w3.org/check/referer 20796 ====================================================================== 20797 http://gcc.gnu.org/egcs-1.0/features.html 20798 EGCS 1.0 features 20799 20800 * Core compiler is based on the gcc2 development tree from Aug 2, 20801 1997, so we have most of the [1]features found in GCC 2.8. 20802 * Integrated GNU Fortran compiler based on g77-0.5.22-19970929. 20803 * Vast improvements in the C++ compiler; so many they have [2]page of 20804 their own! 20805 * Integrated C++ runtime libraries, including support for most major 20806 GNU/Linux systems! 20807 * New instruction scheduler from IBM Haifa which includes support for 20808 function wide instruction scheduling as well as superscalar 20809 scheduling. 20810 * Significantly improved alias analysis code. 20811 * Improved register allocation for two address machines. 20812 * Significant code generation improvements for Fortran code on 20813 Alphas. 20814 * Various optimizations from the g77 project as well as improved loop 20815 optimizations. 20816 * Dwarf2 debug format support for some targets. 20817 * egcs libstdc++ includes the SGI STL implementation without changes. 20818 * As a result of these and other changes, egcs libstc++ is not binary 20819 compatible with previous releases of libstdc++. 20820 * Various new ports -- UltraSPARC, Irix6.2 & Irix6.3 support, The SCO 20821 Openserver 5 family (5.0.{0,2,4} and Internet FastStart 1.0 and 20822 1.1), Support for RTEMS on several embedded targets, Support for 20823 arm-linux, Mitsubishi M32R, Hitachi H8/S, Matsushita MN102 and 20824 MN103, NEC V850, Sparclet, Solaris & GNU/Linux on PowerPCs, etc. 20825 * Integrated testsuites for gcc, g++, g77, libstdc++ and libio. 20826 * RS6000/PowerPC ports generate code which can run on all 20827 RS6000/PowerPC variants by default. 20828 * -mcpu= and -march= switches for the x86 port to allow better 20829 control over how the x86 port generates code. 20830 * Includes the template repository patch (aka repo patch); note the 20831 new template code makes repo obsolete for ELF systems using gnu-ld 20832 such as GNU/Linux. 20833 * Plus the usual assortment of bugfixes and improvements. 20834 20835 20836 For questions related to the use of GCC, please consult these web 20837 pages and the [3]GCC manuals. If that fails, the 20838 [4]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20839 web pages and the development of GCC are welcome on our developer 20840 list at [5]gcc (a] gcc.gnu.org. All of [6]our lists have public archives. 20841 20842 Copyright (C) [7]Free Software Foundation, Inc. Verbatim copying and 20843 distribution of this entire article is permitted in any medium, 20844 provided this notice is preserved. 20845 20846 These pages are [8]maintained by the GCC team. Last modified 20847 2021-07-28[9]. 20848 20849 References 20850 20851 1. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20852 2. http://gcc.gnu.org/egcs-1.0/c++features.html 20853 3. https://gcc.gnu.org/onlinedocs/ 20854 4. mailto:gcc-help (a] gcc.gnu.org 20855 5. mailto:gcc (a] gcc.gnu.org 20856 6. https://gcc.gnu.org/lists.html 20857 7. https://www.fsf.org/ 20858 8. https://gcc.gnu.org/about.html 20859 9. http://validator.w3.org/check/referer 20860 ====================================================================== 20861 http://gcc.gnu.org/egcs-1.0/caveats.html 20862 EGCS 1.0 Caveats 20863 20864 * EGCS has an integrated libstdc++, but does not have an integrated 20865 libg++. Furthermore old libg++ releases will not work with egc; HJ 20866 Lu has made a libg++-2.8.1.2 available which may work with EGCS. 20867 Note most C++ programs only need libstdc++. 20868 * Note that using -pedantic or -Wreturn-type can cause an explosion 20869 in the amount of memory needed for template-heavy C++ code, such as 20870 code that uses STL. Also note that -Wall includes -Wreturn-type, so 20871 if you use -Wall you will need to specify -Wno-return-type to turn 20872 it off. 20873 * Exception handling may not work with shared libraries, particularly 20874 on alphas, hppas, and mips based platforms. Exception handling is 20875 known to work on x86-linux platforms with shared libraries. 20876 * Some versions of the Linux kernel have bugs which prevent them from 20877 being compiled or from running when compiled by EGCS. See the FAQ 20878 (as shipped with EGCS 1.0) for additional information. 20879 * In general, EGCS is more rigorous about rejecting invalid C++ code 20880 or deprecated C++ constructs than G++ 2.7. As a result it may be 20881 necessary to fix C++ code before it will compile with EGCS. 20882 * G++ is also aggressively tracking the C++ standard; as a result 20883 code which was previously valid (and thus accepted by other 20884 compilers and older versions of G++) may no longer be accepted. 20885 * EGCS 1.0 may not work with Red Hat Linux 5.0 on all targets. EGCS 20886 1.0.x and later releases should work with Red Hat Linux 5.0. 20887 20888 20889 For questions related to the use of GCC, please consult these web 20890 pages and the [1]GCC manuals. If that fails, the 20891 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20892 web pages and the development of GCC are welcome on our developer 20893 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 20894 20895 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 20896 distribution of this entire article is permitted in any medium, 20897 provided this notice is preserved. 20898 20899 These pages are [6]maintained by the GCC team. Last modified 20900 2021-07-28[7]. 20901 20902 References 20903 20904 1. https://gcc.gnu.org/onlinedocs/ 20905 2. mailto:gcc-help (a] gcc.gnu.org 20906 3. mailto:gcc (a] gcc.gnu.org 20907 4. https://gcc.gnu.org/lists.html 20908 5. https://www.fsf.org/ 20909 6. https://gcc.gnu.org/about.html 20910 7. http://validator.w3.org/check/referer 20911 ====================================================================== 20912
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