NEWS revision 1.14
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 10 GCC 10 Release Series 11 12 April 8, 2021 13 14 The [1]GNU project and the GCC developers are pleased to announce the 15 release of GCC 10.3. 16 17 This release is a bug-fix release, containing fixes for regressions in 18 GCC 10.2 relative to previous releases of GCC. 19 20 Release History 21 22 GCC 10.3 23 April 8, 2021 ([2]changes, [3]documentation) 24 25 GCC 10.2 26 July 23, 2020 ([4]changes, [5]documentation) 27 28 GCC 10.1 29 May 7, 2020 ([6]changes, [7]documentation) 30 31 References and Acknowledgements 32 33 GCC used to stand for the GNU C Compiler, but since the compiler 34 supports several other languages aside from C, it now stands for the 35 GNU Compiler Collection. 36 37 A list of [8]successful builds is updated as new information becomes 38 available. 39 40 The GCC developers would like to thank the numerous people that have 41 contributed new features, improvements, bug fixes, and other changes as 42 well as test results to GCC. This [9]amazing group of volunteers is 43 what makes GCC successful. 44 45 For additional information about GCC please refer to the [10]GCC 46 project web site or contact the [11]GCC development mailing list. 47 48 To obtain GCC please use [12]our mirror sites or [13]our version 49 control system. 50 51 52 For questions related to the use of GCC, please consult these web 53 pages and the [14]GCC manuals. If that fails, the 54 [15]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 55 web pages and the development of GCC are welcome on our developer 56 list at [16]gcc (a] gcc.gnu.org. All of [17]our lists have public 57 archives. 58 59 Copyright (C) [18]Free Software Foundation, Inc. Verbatim copying and 60 distribution of this entire article is permitted in any medium, 61 provided this notice is preserved. 62 63 These pages are [19]maintained by the GCC team. Last modified 64 2021-04-08[20]. 65 66 References 67 68 1. http://www.gnu.org/ 69 2. http://gcc.gnu.org/gcc-10/changes.html 70 3. http://gcc.gnu.org/onlinedocs/10.3.0/ 71 4. http://gcc.gnu.org/gcc-10/changes.html 72 5. http://gcc.gnu.org/onlinedocs/10.2.0/ 73 6. http://gcc.gnu.org/gcc-10/changes.html 74 7. http://gcc.gnu.org/onlinedocs/10.1.0/ 75 8. http://gcc.gnu.org/gcc-10/buildstat.html 76 9. http://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Contributors.html 77 10. http://gcc.gnu.org/index.html 78 11. mailto:gcc (a] gcc.gnu.org 79 12. http://gcc.gnu.org/mirrors.html 80 13. http://gcc.gnu.org/git.html 81 14. https://gcc.gnu.org/onlinedocs/ 82 15. mailto:gcc-help (a] gcc.gnu.org 83 16. mailto:gcc (a] gcc.gnu.org 84 17. https://gcc.gnu.org/lists.html 85 18. https://www.fsf.org/ 86 19. https://gcc.gnu.org/about.html 87 20. http://validator.w3.org/check/referer 88 ====================================================================== 89 http://gcc.gnu.org/gcc-10/changes.html 90 91 GCC 10 Release Series 92 Changes, New Features, and Fixes 93 94 This page is a "brief" summary of some of the huge number of 95 improvements in GCC 10. You may also want to check out our [1]Porting 96 to GCC 10 page and the [2]full GCC documentation. 97 98 Caveats 99 100 * An ABI incompatibility between C++14 and C++17 has been fixed. On 101 some targets a class with a zero-sized subobject would be passed 102 incorrectly when compiled as C++17 or C++20. See the [3]C++ notes 103 below for more details. 104 * The deprecated Profile Mode and array_allocator extensions have 105 been removed from libstdc++. 106 * The non-standard std::__is_nullptr_t type trait is deprecated and 107 will be removed from libstdc++ in a future release. The standard 108 trait std::is_null_pointer should be instead. 109 * The minimum version of the [4]MPFR library required for building 110 GCC has been increased to version 3.1.0 (released 2011-10-03). 111 * The automatic template instantiation at link time (-frepo) has been 112 removed. 113 * The --param allow-store-data-races internal parameter has been 114 removed in favor of a new official option -fallow-store-data-races. 115 While default behavior is unchanged and the new option allows to 116 correctly maintain a per compilation unit setting across link-time 117 optimization, alteration of the default via --param 118 allow-store-data-races will now be diagnosed and build systems have 119 to be adjusted accordingly. 120 * Offloading to Heterogeneous System Architecture Intermediate 121 Language (HSAIL) has been deprecated and will likely be removed in 122 a future release. 123 * The type of the std::iterator base class of 124 std::istreambuf_iterator was changed in C++98 mode to be consistent 125 with C++11 and later standards. See the [5]libstdc++ notes below 126 for more details. 127 128 General Improvements 129 130 * New built-in functions: 131 + The [6]__has_builtin built-in preprocessor operator can be 132 used to query support for built-in functions provided by GCC 133 and other compilers that support it. 134 + __builtin_roundeven for the corresponding function from 135 ISO/IEC TS 18661. 136 * New command-line options: 137 + [7]-fallocation-dce removes unneeded pairs of new and delete 138 operators. 139 + [8]-fprofile-partial-training can now be used to inform the 140 compiler that code paths not covered by the training run 141 should not be optimized for size. 142 + [9]-fprofile-reproducible controls level of reproducibility of 143 profile gathered by [10]-fprofile-generate. This makes it 144 possible to rebuild program with same outcome which is useful, 145 for example, for distribution packages. 146 + [11]-fprofile-prefix-path can be used in combination with 147 -fprofile-generate=profile_dir and -fprofile-use=profile_dir 148 to inform GCC where the base directory of build source tree is 149 in case it differs between instrumentation and optimized 150 builds. 151 + [12]-fanalyzer enables a new static analysis pass and 152 associated warnings. This pass performs a time-consuming 153 exploration of paths through the code in the hope of detecting 154 various common errors, such as double-free bugs. This option 155 should be regarded as experimental in this release. In 156 particular, analysis of non-C code is unlikely to work. 157 * Inter-procedural optimization improvements: 158 + The inter-procedural scalar replacement of aggregates 159 (IPA-SRA) pass was re-implemented to work at link-time and can 160 now also remove computing and returning unused return values. 161 + [13]-finline-functions is now enabled at -O2 and was retuned 162 for better code size versus runtime performance trade-offs. 163 Inliner heuristics was also significantly sped up to avoid 164 negative impact to -flto -O2 compile times. 165 + Inliner heuristics and function cloning can now use 166 value-range information to predict effectivity of individual 167 transformations. 168 + During link-time optimization the C++ One Definition Rule is 169 used to increase precision of type based alias analysis. 170 * Link-time optimization improvements: 171 + A new binary [14]lto-dump has been added. It dumps various 172 information about LTO bytecode object files. 173 + The parallel phase of the LTO can automatically detect a 174 running make's jobserver or fall back to number of available 175 cores. 176 + The LTO bytecode can be compressed with the [15]zstd 177 algorithm. The configure script automatically detects zstd 178 support. 179 + Most --param values can now be specified at translation unit 180 granularity. This includes all parameters controlling the 181 inliner and other inter-procedural optimizations. Unlike 182 earlier releases, GCC 10 will ignore parameters controlling 183 optimizations specified at link-time and apply parameters 184 specified at compile-time in the same manner as done for 185 optimization flags. 186 * Profile driven optimization improvements: 187 + Profile maintenance during compilation and hot/cold code 188 partitioning have been improved. 189 + Using [16]-fprofile-values, an instrumented binary can track 190 multiple values (up to 4) for e.g. indirect calls and provide 191 more precise profile information. 192 193 New Languages and Language-Specific Improvements 194 195 * Version 2.6 of the [17]OpenACC specification is now supported in 196 the C, C++ and Fortran compilers. See the [18]implementation status 197 section on the OpenACC wiki page and the [19]run-time library 198 documentation for further information. 199 * GCC 10 adds a number of newly implemented [20]OpenMP 5.0 features 200 on top of the GCC 9 release such as conditional lastprivate clause, 201 scan and loop directives, order(concurrent) and use_device_addr 202 clauses support, if clause on simd construct or partial support for 203 the declare variant directive, getting closer to full support of 204 the OpenMP 5.0 standard. 205 * OpenMP and OpenACC now support [21]offloading to AMD Radeon (GCN) 206 GPUs; supported are the third-generation Fiji (fiji) and the 207 fifth-generation VEGA 10/VEGA 20 (gfx900 or gfx906). 208 209 C family 210 211 * New attributes: 212 + The access function and type attribute has been added to 213 describe how a function accesses objects passed to it by 214 pointer or reference, and to associate such arguments with 215 integer arguments denoting the objects' sizes. The attribute 216 is used to enable the detection of invalid accesses by 217 user-defined functions, such as those diagnosed by 218 -Wstringop-overflow. 219 + The symver attribute can be used to bind symbols to specific 220 version nodes on ELF platforms. This is preferred to using 221 inline assembly with GNU as symver directive because the 222 latter is not compatible with link-time optimizations. 223 * New warnings: 224 + [22]-Wstring-compare, enabled by -Wextra, warns about equality 225 and inequality expressions between zero and the result of a 226 call to either strcmp and strncmp that evaluate to a constant 227 as a result of the length of one argument being greater than 228 the size of the array pointed to by the other. 229 + [23]-Wzero-length-bounds, enabled by -Warray-bounds, warns 230 about accesses to elements of zero-length arrays that might 231 overlap other members of the same object. 232 * Enhancements to existing warnings: 233 + [24]-Warray-bounds detects more out-of-bounds accesses to 234 member arrays as well as accesses to elements of zero-length 235 arrays. 236 + [25]-Wformat-overflow makes full use of string length 237 information computed by the strlen optimization pass. 238 + [26]-Wrestrict detects overlapping accesses to dynamically 239 allocated objects. 240 + [27]-Wreturn-local-addr diagnoses more instances of return 241 statements returning addresses of automatic variables. 242 + [28]-Wstringop-overflow detects more out-of-bounds stores to 243 member arrays including zero-length arrays, dynamically 244 allocated objects and variable length arrays, as well as more 245 instances of reads of unterminated character arrays by string 246 built-in functions. The warning also detects out-of-bounds 247 accesses by calls to user-defined functions declared with the 248 new attribute access. 249 + [29]-Warith-conversion re-enables warnings from -Wconversion, 250 -Wfloat-conversion, and -Wsign-conversion that are now off by 251 default for an expression where the result of an arithmetic 252 operation will not fit in the target type due to promotion, 253 but the operands of the expression do fit in the target type. 254 * Extended characters in identifiers may now be specified directly in 255 the input encoding (UTF-8, by default), in addition to the UCN 256 syntax (\uNNNN or \UNNNNNNNN) that is already supported: 257 258 static const int p = 3; 259 int get_nave_pi() { 260 return p; 261 } 262 263 C 264 265 * Several new features from the upcoming C2X revision of the ISO C 266 standard are supported with -std=c2x and -std=gnu2x. Some of these 267 features are also supported as extensions when compiling for older 268 language versions. In addition to the features listed, some 269 features previously supported as extensions and now added to the C 270 standard are enabled by default in C2X mode and not diagnosed with 271 -std=c2x -Wpedantic. 272 + The [[]] attribute syntax is supported, as in C++. Existing 273 attributes can be used with this syntax in forms such as 274 [[gnu::const]]. The standard attributes [[deprecated]], 275 [[fallthrough]] and [[maybe_unused]] are supported. 276 + UTF-8 character constants using the u8'' syntax are supported. 277 + <float.h> defines macros FLT_NORM_MAX, DBL_NORM_MAX and 278 LDBL_NORM_MAX. 279 + When decimal floating-point arithmetic is supported, <float.h> 280 defines macros DEC32_TRUE_MIN, DEC64_TRUE_MIN and 281 DEC128_TRUE_MIN, in addition to the macros that were 282 previously only defined if __STDC_WANT_DEC_FP__ was defined 283 before including <float.h>. 284 + In C2X mode, empty parentheses in a function definition give 285 that function a type with a prototype for subsequent calls; 286 other old-style function definitions are diagnosed by default 287 in C2X mode. 288 + The strftime format checking supports the %OB and %Ob formats. 289 + In C2X mode, -fno-fp-int-builtin-inexact is enabled by 290 default. 291 * GCC now defaults to -fno-common. As a result, global variable 292 accesses are more efficient on various targets. In C, global 293 variables with multiple tentative definitions now result in linker 294 errors. With -fcommon such definitions are silently merged during 295 linking. 296 297 C++ 298 299 * Several C++20 features have been implemented: 300 + Concepts, including P0734R0, P0857R0, P1084R2, P1141R2, 301 P0848R3, P1616R1, P1452R2 302 + P1668R1, Permitting Unevaluated inline-assembly in constexpr 303 Functions 304 + P1161R3, Deprecate a[b,c] 305 + P0848R3, Conditionally Trivial Special Member Functions 306 + P1091R3, Extending structured bindings 307 + P1143R2, Adding the constinit keyword 308 + P1152R4, Deprecating volatile 309 + P0388R4, Permit conversions to arrays of unknown bound 310 + P0784R7, constexpr new 311 + P1301R4, [[nodiscard("with reason")]] 312 + P1814R0, class template argument deduction for alias templates 313 + P1816R0, class template argument deduction for aggregates 314 + P0960R3, Parenthesized initialization of aggregates 315 + P1331R2, Allow trivial default initialization in constexpr 316 contexts 317 + P1327R1, Allowing dynamic_cast and polymorphic typeid in 318 constexpr contexts 319 + P0912R5, Coroutines (requires -fcoroutines) 320 * Several C++ Defect Reports have been resolved, e.g.: 321 + DR 1560, lvalue-to-rvalue conversion in ?: 322 + DR 1813, __is_standard_layout for a class with repeated bases 323 + DR 2094, volatile scalars are trivially copyable, 324 + DR 2096, constraints on literal unions 325 + DR 2413, typename in conversion-function-ids 326 + DR 2352, Similar types and reference binding 327 + DR 1601, Promotion of enumeration with fixed underlying type 328 + DR 330, Qualification conversions and pointers to arrays of 329 pointers 330 + DR 1307, Overload resolution based on size of array 331 initializer-list 332 + DR 1710, Missing template keyword in class-or-decltype 333 * New warnings: 334 + [30]-Wmismatched-tags, disabled by default, warns about 335 declarations of structs, classes, and class templates and 336 their specializations with a class-key that does not match 337 either the definition or the first declaration if no 338 definition is provided. The option is provided to ease 339 portability to Windows-based compilers. 340 + [31]-Wredundant-tags, disabled by default, warns about 341 redundant class-key and enum-key in contexts where the key can 342 be eliminated without causing an syntactic ambiguity. 343 * G++ can now detect modifying constant objects in constexpr 344 evaluation (which is undefined behavior). 345 * G++ no longer emits bogus -Wsign-conversion warnings with explicit 346 casts. 347 * Narrowing is now detected in more contexts (e.g., case values). 348 * Memory consumption of the compiler has been reduced in constexpr 349 evaluation. 350 * The noexcept-specifier is now properly treated as a complete-class 351 context as per [class.mem]. 352 * The attribute deprecated can now be used on namespaces too. 353 * The ABI of passing and returning certain C++ classes by value 354 changed on several targets in GCC 10, including [32]AArch64, 355 [33]ARM, [34]PowerPC ELFv2, [35]S/390 and [36]Itanium. These 356 changes affect classes with a zero-sized subobject (an empty base 357 class, or data member with the [[no_unique_address]] attribute) 358 where all other non-static data members have the same type (this is 359 called a "homogeneous aggregate" in some ABI specifications, or if 360 there is only one such member, a "single element"). In -std=c++17 361 and -std=c++20 modes, classes with an empty base class were not 362 considered to have a single element or to be a homogeneous 363 aggregate, and so could be passed differently (in the wrong 364 registers or at the wrong stack address). This could make code 365 compiled with -std=c++17 and -std=c++14 ABI incompatible. This has 366 been corrected and the empty bases are ignored in those ABI 367 decisions, so functions compiled with -std=c++14 and -std=c++17 are 368 now ABI compatible again. Example: struct empty {}; struct S : 369 empty { float f; }; void f(S);. Similarly, in classes containing 370 non-static data members with empty class types using the C++20 371 [[no_unique_address]] attribute, those members weren't ignored in 372 the ABI argument passing decisions as they should be. Both of these 373 ABI changes are now diagnosed with -Wpsabi. 374 375 Runtime Library (libstdc++) 376 377 * Improved experimental C++2a support, including: 378 + Library concepts in <concepts> and <iterator>. 379 + Constrained algorithms in <ranges>, <algorithm>, and <memory> 380 (thanks to Patrick Palka). 381 + New algorithms shift_left and shift_right (thanks to Patrick 382 Palka). 383 + std::span (thanks to JeanHeyd Meneide). 384 + Three-way comparisons in <compare> and throughout the library. 385 + Constexpr support in <algorithm> and elsewhere (thanks to 386 Edward Smith-Rowland). 387 + <stop_token> and std::jthread (thanks to Thomas Rodgers). 388 + std::atomic_ref and std::atomic<floating point>. 389 + Integer comparison functions (cmp_equal, cmp_less etc.). 390 + std::ssize, std::to_array. 391 + std::construct_at, std::destroy, constexpr std::allocator. 392 + Mathematical constants in <numbers>. 393 * Support for RDSEED in std::random_device. 394 * Reduced header dependencies, leading to faster compilation for some 395 code. 396 * The std::iterator base class of std::istreambuf_iterator was 397 changed in C++98 mode to be consistent with C++11 and later 398 standards. This is expected to have no noticeable effect except in 399 the unlikely case of a class which has potentially overlapping 400 subobjects of type std::istreambuf_iterator<C> and another iterator 401 type with a std::iterator<input_iterator_tag, C, ...> base class. 402 The layout of such a type might change when compiled as C++98. 403 [37]Bug 92285 has more details and concrete examples. 404 405 D 406 407 * Support for static foreach has been implemented. 408 * Aliases can now be created directly from any __traits that return 409 symbols or tuples. Previously, an AliasSeq was necessary in order 410 to alias their return. 411 * It is now possible to detect the language ABI specified for a 412 struct, class, or interface using __traits(getLinkage, ...). 413 * Support for core.math.toPrec intrinsics has been added. These 414 intrinsics guarantee the rounding to specific floating-point 415 precisions at specified points in the code. 416 * Support for pragma(inline) has been implemented. Previously the 417 pragma was recognized, but had no effect on the compilation. 418 * Optional parentheses in asm operands are deprecated and will be 419 removed in a future release. 420 * All content imported files are now included in the make dependency 421 list when compiling with -M. 422 * Compiler recognized attributes provided by the gcc.attribute module 423 will now take effect when applied to function prototypes as well as 424 when applied to full function declarations. 425 * Added a --enable-libphobos-checking configure option to control 426 whether run-time checks are compiled into the D runtime library. 427 * Added a --with-libphobos-druntime-only configure option to indicate 428 whether to build only the core D runtime library, or both the core 429 and standard libraries into libphobos. 430 431 Fortran 432 433 * use_device_addr of version 5.0 of the [38]OpenMP specification is 434 now supported. Note that otherwise OpenMP 4.5 is partially 435 supported in the Fortran compiler; the largest missing item is 436 structure element mapping. 437 * The default buffer size for I/O using unformatted files has been 438 increased to 1048576. The buffer size for can now be set at runtime 439 via the environment variables GFORTRAN_FORMATTED_BUFFER_SIZE and 440 GFORTRAN_UNFORMATTED_BUFFER_SIZE for formatted and unformatted 441 files, respectively. 442 * Mismatches between actual and dummy argument lists in a single file 443 are now rejected with an error. Use the new option 444 -fallow-argument-mismatch to turn these errors into warnings; this 445 option is implied with -std=legacy. -Wargument-mismatch has been 446 removed. 447 * The handling of a BOZ literal constant has been reworked to provide 448 better conformance to the Fortran 2008 and 2018 standards. In these 449 Fortran standards, a BOZ literal constant is a typeless and 450 kindless entity. As a part of the rework, documented and 451 undocumented extensions to the Fortran standard now emit errors 452 during compilation. Some of these extensions are permitted with the 453 -fallow-invalid-boz option, which degrades the error to a warning 454 and the code is compiled as with older gfortran. 455 * At any optimization level except-Os, gfortran now uses inline 456 packing for arguments instead of calling a library routine. If the 457 source contains a large number of arguments that need to be 458 repacked, code size or time for compilation can become excessive. 459 If that is the case, -fno-inline-arg-packing can be used to disable 460 inline argument packing. 461 * Legacy extensions: 462 + For formatted input/output, if the explicit widths after the 463 data-edit descriptors I, F and G have been omitted, default 464 widths are used. 465 + A blank format item at the end of a format specification, i.e. 466 nothing following the final comma, is allowed. Use the option 467 -fdec-blank-format-item; this option is implied with -fdec. 468 + The existing support for AUTOMATIC and STATIC attributes has 469 been extended to allow variables with the AUTOMATIC attribute 470 to be used in EQUIVALENCE statements. Use -fdec-static; this 471 option is implied by -fdec. 472 + Allow character literals in assignments and DATA statements 473 for numeric (INTEGER, REAL, or COMPLEX) or LOGICAL variables. 474 Use the option -fdec-char-conversions; this option is implied 475 with -fdec. 476 + DEC comparisons, i.e. allow Hollerith constants to be used in 477 comparisons with INTEGER, REAL, COMPLEX and CHARACTER 478 expressions. Use the option -fdec. 479 * Character type names in errors and warnings now include len in 480 addition to kind; * is used for assumed length. The kind is omitted 481 if it is the default kind. Examples: CHARACTER(12), CHARACTER(6,4). 482 * CO_BROADCAST now supports derived type variables including objects 483 with allocatable components. In this case, the optional arguments 484 STAT= and ERRMSG= are currently ignored. 485 * The handling of module and submodule names has been reworked to 486 allow the full 63-character length mandated by the standard. 487 Previously symbol names were truncated if the combined length of 488 module, submodule, and function name exceeded 126 characters. This 489 change therefore breaks the ABI, but only for cases where this 126 490 character limit was exceeded. 491 492 libgccjit 493 494 * The libgccjit API gained four new entry points: 495 + [39]gcc_jit_version_major, [40]gcc_jit_version_minor, and 496 [41]gcc_jit_version_patchlevel for programmatically checking 497 the libgccjit version from client code, and 498 + [42]gcc_jit_context_new_bitfield 499 500 New Targets and Target Specific Improvements 501 502 AArch64 & arm 503 504 * The AArch64 and arm ports now support condition flag output 505 constraints in inline assembly, as indicated by the 506 __GCC_ASM_FLAG_OUTPUTS__. On arm this feature is only available for 507 A32 and T32 targets. Please refer to the documentation for more 508 details. 509 510 AArch64 511 512 * There have been several improvements related to the Scalable Vector 513 Extension (SVE): 514 + The SVE ACLE types and intrinsics are now supported. They can 515 be accessed using the header file arm_sve.h. 516 + It is now possible to create fixed-length SVE types using the 517 arm_sve_vector_bits attribute. For example: 518 #if __ARM_FEATURE_SVE_BITS==512 519 typedef svint32_t vec512 __attribute__((arm_sve_vector_bits(512))); 520 typedef svbool_t pred512 __attribute__((arm_sve_vector_bits(512))); 521 #endif 522 + -mlow-precision-div, -mlow-precision-sqrt and 523 -mlow-precision-recip-sqrt now work for SVE. 524 + -msve-vector-bits=128 now generates vector-length-specific 525 code for little-endian targets. It continues to generate 526 vector-length-agnostic code for big-endian targets, just as 527 previous releases did for all targets. 528 + The vectorizer is now able to use extending loads and 529 truncating stores, including gather loads and scatter stores. 530 + The vectorizer now compares the cost of vectorizing with SVE 531 and vectorizing with Advanced SIMD and tries to pick the best 532 one. Previously it would always use SVE if possible. 533 + If a vector loop uses Advanced SIMD rather than SVE, the 534 vectorizer now considers using SVE to vectorize the left-over 535 elements (the "scalar tail" or "epilog"). 536 + Besides these specific points, there have been many general 537 improvements to the way that the vectorizer uses SVE. 538 * The -mbranch-protection=pac-ret option now accepts the optional 539 argument +b-key extension to perform return address signing with 540 the B-key instead of the A-key. 541 * The option -moutline-atomics has been added to aid deployment of 542 the Large System Extensions (LSE) on GNU/Linux systems built with a 543 baseline architecture targeting Armv8-A. When the option is 544 specified code is emitted to detect the presence of LSE 545 instructions at runtime and use them for standard atomic 546 operations. For more information please refer to the documentation. 547 * The Transactional Memory Extension is now supported through ACLE 548 intrinsics. It can be enabled through the +tme option extension 549 (for example, -march=armv8.5-a+tme). 550 * A number of features from Armv8.5-A are now supported through ACLE 551 intrinsics. These include: 552 + The random number instructions that can be enabled through the 553 (already present in GCC 9.1) +rng option extension. 554 + Floating-point intrinsics to round to integer instructions 555 from Armv8.5-A when targeting -march=armv8.5-a or later. 556 + Memory Tagging Extension intrinsics enabled through the 557 +memtag option extension. 558 * Similarly, the following Armv8.6-A features are now supported 559 through ACLE intrinsics: 560 + The bfloat16 extension. This extension is enabled 561 automatically when Armv8.6-A is selected (such as by 562 -march=armv8.6-a). It can also be enabled for Armv8.2-A and 563 later using the +bf16 option extension. 564 + The Matrix Multiply extension. This extension is split into 565 three parts, one for each supported data type: 566 o Support for 8-bit integer matrix multiply instructions. 567 This extension is enabled automatically when Armv8.6-A is 568 selected. It can also be enabled for Armv8.2-A and later 569 using the +i8mm option extension. 570 o Support for 32-bit floating-point matrix multiply 571 instructions. This extension can be enabled using the 572 +f32mm option extension, which also has the effect of 573 enabling SVE. 574 o Support for 64-bit floating-point matrix multiply 575 instructions. This extension can be enabled using the 576 +f64mm option extension, which likewise has the effect of 577 enabling SVE. 578 * SVE2 is now supported through ACLE intrinsics and (to a limited 579 extent) through autovectorization. It can be enabled through the 580 +sve2 option extension (for example, -march=armv8.5-a+sve2). 581 Additional extensions can be enabled through +sve2-sm4, +sve2-aes, 582 +sve2-sha3 and +sve2-bitperm. 583 * Support has been added for the following processors (GCC 584 identifiers in parentheses): 585 + Arm Cortex-A77 (cortex-a77). 586 + Arm Cortex-A76AE (cortex-a76ae). 587 + Arm Cortex-A65 (cortex-a65). 588 + Arm Cortex-A65AE (cortex-a65ae). 589 + Arm Cortex-A34 (cortex-a34). 590 + Marvell ThunderX3 (thunderx3t110). 591 The GCC identifiers can be used as arguments to the -mcpu or -mtune 592 options, for example: -mcpu=cortex-a77 or -mtune=cortex-a65ae or as 593 arguments to the equivalent target attributes and pragmas. 594 595 arm 596 597 * Support for the FDPIC ABI has been added. It uses 64-bit function 598 descriptors to represent pointers to functions, and enables code 599 sharing on MMU-less systems. The corresponding target triple is 600 arm-uclinuxfdpiceabi, and the C library is uclibc-ng. 601 * Support has been added for the Arm EABI on NetBSD through the 602 arm*-*-netbsdelf-*eabi* triplet. 603 * The handling of 64-bit integer operations has been significantly 604 reworked and improved leading to improved performance and reduced 605 stack usage when using 64-bit integral data types. The option 606 -mneon-for-64bits is now deprecated and will be removed in a future 607 release. 608 * Support has been added for the following processors (GCC 609 identifiers in parentheses): 610 + Arm Cortex-A77 (cortex-a77). 611 + Arm Cortex-A76AE (cortex-a76ae). 612 + Arm Cortex-M35P (cortex-m35p). 613 + Arm Cortex-M55 (cortex-m55). 614 The GCC identifiers can be used as arguments to the -mcpu or -mtune 615 options, for example: -mcpu=cortex-a77 or -mtune=cortex-m35p. 616 * Support has been extended for the ACLE [43]data-processing 617 intrinsics to include 32-bit SIMD, saturating arithmetic, 16-bit 618 multiplication and other related intrinsics aimed at DSP algorithm 619 optimization. 620 * Support for -mpure-code in Thumb-1 (v6m) has been added: this 621 M-profile feature is no longer restricted to targets with MOVT. For 622 example, -mcpu=cortex-m0 now supports this option. 623 * Support for the [44]Armv8.1-M Mainline Architecture has been added. 624 + Armv8.1-M Mainline can be enabled by using the 625 -march=armv8.1-m.main command-line option. 626 * Support for the [45]MVE beta ACLE intrinsics has been added. These 627 intrinsics can be enabled by including the arm_mve.h header file 628 and passing the +mve or +mve.fp option extensions (for example: 629 -march=armv8.1-m.main+mve). 630 * Support for the Custom Datapath Extension beta ACLE [46]intrinsics 631 has been added. 632 * Support for Armv8.1-M Mainline Security Extensions architecture has 633 been added. The -mcmse option, when used in combination with an 634 Armv8.1-M Mainline architecture (for example: -march=armv8.1-m.main 635 -mcmse), now leads to the generation of improved code sequences 636 when changing security states. 637 638 AMD Radeon (GCN) 639 640 * The code generation and in particular the vectorization support has 641 been much improved. 642 643 ARC 644 645 * The interrupt service routine functions save all used registers, 646 including extension registers and auxiliary registers used by Zero 647 Overhead Loops. 648 * Improve code size by using multiple short instructions instead of a 649 single long mov or ior instruction when its long immediate constant 650 is known. 651 * Fix usage of the accumulator register for ARC600. 652 * Fix issues with uncached attribute. 653 * Remove -mq-class option. 654 * Improve 64-bit integer addition and subtraction operations. 655 656 AVR 657 658 * Support for the XMEGA-like devices 659 660 ATtiny202, ATtiny204, ATtiny402, ATtiny404, ATtiny406, ATtiny804, 661 ATtiny806, ATtiny807, ATtiny1604, ATtiny1606, ATtiny1607, ATmega808, 662 ATmega809, ATmega1608, ATmega1609, ATmega3208, ATmega3209, 663 ATmega4808, ATmega4809 664 has been added. 665 * A new command-line option -nodevicespecs has been added. It allows 666 to provide a custom device-specs file by means of 667 668 avr-gcc -nodevicespecs -specs=my-spec-file <options> 669 and without the need to provide options -B and -mmcu=. See [47]AVR 670 command-line options for details. This feature is also available in 671 GCC 9.3+ and GCC 8.4+. 672 * New command-line options -mdouble=[32,64] and -mlong-double=[32,64] 673 have been added. They allow to choose the size (in bits) of the 674 double and long double types, respectively. Whether or not the 675 mentioned layouts are available, whether the options act as a 676 multilib option, and the default for either option are controlled 677 by the new [48]AVR configure options --with-double= and 678 --with-long-double=. 679 * A new configure option --with-libf7= has been added. It controls to 680 which level avr-libgcc provides 64-bit floating point support by 681 means of [49]Libf7. 682 * A new configure option --with-double-comparison= has been added. 683 It's unlikely you need to set this option by hand. 684 685 IA-32/x86-64 686 687 * Support to expand __builtin_roundeven into the appropriate SSE 4.1 688 instruction has been added. 689 * New ISA extension support for Intel ENQCMD was added to GCC. ENQCMD 690 intrinsics are available via the -menqcmd compiler switch. 691 * GCC now supports the Intel CPU named Cooperlake through 692 -march=cooperlake. The switch enables the AVX512BF16 ISA 693 extensions. 694 * GCC now supports the Intel CPU named Tigerlake through 695 -march=tigerlake. The switch enables the MOVDIRI MOVDIR64B 696 AVX512VP2INTERSECT ISA extensions. 697 698 MIPS 699 700 * The mips*-*-linux* targets now mark object files with appropriate 701 GNU-stack note, facilitating use of non-executable stack hardening 702 on GNU/Linux. The soft-float targets have this feature enabled by 703 default, while for hard-float targets it is required for GCC to be 704 configured with --with-glibc-version=2.31 against glibc 2.31 or 705 later. 706 707 PowerPC / PowerPC64 / RS6000 708 709 * Many vector builtins have been listed as deprecated in the 710 [50]64-Bit ELF V2 ABI Specification for quite a number of years. 711 The vector builtins listed in Tables A.8 through A.10 are now 712 deprecated for GCC 10, and will likely be removed from support in 713 GCC 11. Note that this does not result in any loss of function. 714 These deprecated builtins generally provide somewhat nonsensical 715 argument lists (for example, mixing signed, unsigned, and bool 716 vector arguments arbitrarily), or are duplicate builtins that are 717 inconsistent with the expected naming scheme. We expect that this 718 will be unlikely to affect much if any code, and any required code 719 changes will be trivial. 720 721 PRU 722 723 * A new back end targeting TI PRU I/O processors has been contributed 724 to GCC. 725 726 RISC-V 727 728 * The riscv*-*-* targets now require GNU binutils version 2.30 or 729 later, to support new assembly instructions produced by GCC. 730 731 V850 732 733 * The ABI for V850 nested functions has been changed. Previously the 734 V850 port used %r20 for the static chain pointer, now the port uses 735 %r19. This corrects a long standing latent bug in the v850 port 736 where a call to a nested function would unexpectedly change the 737 value in %r20. 738 739 Operating Systems 740 741 Improvements for plugin authors 742 743 * GCC diagnostics can now have a chain of events associated with 744 them, describing a path through the code that triggers the problem. 745 These can be printed by the diagnostics subsystem in various ways, 746 controlled by the [51]-fdiagnostics-path-format option, or captured 747 in JSON form via [52]-fdiagnostics-format=json. 748 * GCC diagnostics can now be associated with [53]CWE weakness 749 identifiers, which will appear on the standard error stream, and in 750 the JSON output from [54]-fdiagnostics-format=json. 751 752 Other significant improvements 753 754 * To allow inline expansion of both memcpy and memmove, the existing 755 movmem instruction patterns used for non-overlapping memory copies 756 have been renamed to cpymem. The movmem name is now used for 757 overlapping memory moves, consistent with the library functions 758 memcpy and memmove. 759 * For many releases, when GCC emits a warning it prints the option 760 controlling that warning. As of GCC 10, that option text is now a 761 clickable hyperlink for the documentation of that option (assuming 762 a [55]sufficiently capable terminal). This behavior can be 763 controlled via a new [56]-fdiagnostics-urls option (along with 764 various environment variables and heuristics documented with that 765 option). 766 767 GCC 10.1 768 769 This is the [57]list of problem reports (PRs) from GCC's bug tracking 770 system that are known to be fixed in the 10.1 release. This list might 771 not be complete (that is, it is possible that some PRs that have been 772 fixed are not listed here). 773 774 GCC 10.2 775 776 This is the [58]list of problem reports (PRs) from GCC's bug tracking 777 system that are known to be fixed in the 10.2 release. This list might 778 not be complete (that is, it is possible that some PRs that have been 779 fixed are not listed here). 780 781 GCC 10.3 782 783 This is the [59]list of problem reports (PRs) from GCC's bug tracking 784 system that are known to be fixed in the 10.3 release. This list might 785 not be complete (that is, it is possible that some PRs that have been 786 fixed are not listed here). 787 788 Target Specific Changes 789 790 AArch64 791 792 * A bug with the Random Number intrinsics in the arm_acle.h header 793 that resulted in an incorrect status result being returned has been 794 fixed. 795 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 796 options are -mcpu=a64fx and -mtune=a64fx respectively. In 797 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 798 tunes the code for the A64FX. This includes tuning the SVE code, 799 although by default the code is still length-agnostic and so works 800 for all SVE implementations. Adding -msve-vector-bits=512 makes the 801 code specific to 512-bit SVE. 802 803 804 For questions related to the use of GCC, please consult these web 805 pages and the [60]GCC manuals. If that fails, the 806 [61]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 807 web pages and the development of GCC are welcome on our developer 808 list at [62]gcc (a] gcc.gnu.org. All of [63]our lists have public 809 archives. 810 811 Copyright (C) [64]Free Software Foundation, Inc. Verbatim copying and 812 distribution of this entire article is permitted in any medium, 813 provided this notice is preserved. 814 815 These pages are [65]maintained by the GCC team. Last modified 816 2021-04-08[66]. 817 818 References 819 820 1. http://gcc.gnu.org/gcc-10/porting_to.html 821 2. http://gcc.gnu.org/onlinedocs/index.html#current 822 3. http://gcc.gnu.org/gcc-10/changes.html#empty_base 823 4. https://www.mpfr.org/ 824 5. http://gcc.gnu.org/gcc-10/changes.html#iterator_base 825 6. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/cpp/_005f_005fhas_005fbuiltin.html#g_t_005f_005fhas_005fbuiltin 826 7. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fno-allocation-dce 827 8. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-partial-training 828 9. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-reproducible 829 10. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-generate 830 11. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Instrumentation-Options.html#index-fprofile-prefix-path 831 12. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html 832 13. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-finline-functions 833 14. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/lto-dump.html 834 15. https://facebook.github.io/zstd/ 835 16. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Optimize-Options.html#index-fprofile-values 836 17. https://www.openacc.org/ 837 18. https://gcc.gnu.org/wiki/OpenACC#status-10 838 19. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/libgomp/#toc-Enabling-OpenACC-1 839 20. https://www.openmp.org/specifications/ 840 21. https://gcc.gnu.org/wiki/Offloading 841 22. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstring-compare 842 23. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wzero-length-bounds 843 24. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warray-bounds 844 25. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wformat-overflow 845 26. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wrestrict 846 27. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wreturn-local-addr 847 28. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Wstringop-overflow 848 29. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Warning-Options.html#index-Warith-conversion 849 30. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wmismatched-tags 850 31. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/C_002b_002b-Dialect-Options.html#index-Wredundant-tags 851 32. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94383 852 33. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94711 853 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94707 854 35. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94704 855 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94706 856 37. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92285 857 38. https://www.openmp.org/specifications/ 858 39. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_major 859 40. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_minor 860 41. https://gcc.gnu.org/onlinedocs/jit/topics/compatibility.html#c.gcc_jit_version_patchlevel 861 42. https://gcc.gnu.org/onlinedocs/jit/topics/types.html#c.gcc_jit_context_new_bitfield 862 43. https://developer.arm.com/documentation/101028/0009/Data-processing-intrinsics 863 44. https://developer.arm.com/architectures/cpu-architecture/m-profile 864 45. https://developer.arm.com/architectures/instruction-sets/simd-isas/helium/helium-intrinsics 865 46. https://developer.arm.com/documentation/101028/0010/Custom-Datapath-Extension 866 47. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/AVR-Options.html#index-nodevicespecs 867 48. https://gcc.gnu.org/install/configure.html#avr 868 49. https://gcc.gnu.org/wiki/avr-gcc#Libf7 869 50. https://openpowerfoundation.org/?resource_lib=64-bit-elf-v2-abi-specification-power-architecture 870 51. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-path-format 871 52. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 872 53. https://cwe.mitre.org/ 873 54. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 874 55. https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda 875 56. https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-urls 876 57. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.0 877 58. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.2 878 59. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=10.3 879 60. https://gcc.gnu.org/onlinedocs/ 880 61. mailto:gcc-help (a] gcc.gnu.org 881 62. mailto:gcc (a] gcc.gnu.org 882 63. https://gcc.gnu.org/lists.html 883 64. https://www.fsf.org/ 884 65. https://gcc.gnu.org/about.html 885 66. http://validator.w3.org/check/referer 886 ====================================================================== 887 http://gcc.gnu.org/gcc-9/index.html 888 889 GCC 9 Release Series 890 891 Mar 12, 2020 892 893 The [1]GNU project and the GCC developers are pleased to announce the 894 release of GCC 9.3. 895 896 This release is a bug-fix release, containing fixes for regressions in 897 GCC 9.2 relative to previous releases of GCC. 898 899 Release History 900 901 GCC 9.3 902 Mar 12, 2020 ([2]changes, [3]documentation) 903 904 GCC 9.2 905 Aug 12, 2019 ([4]changes, [5]documentation) 906 907 GCC 9.1 908 May 3, 2019 ([6]changes, [7]documentation) 909 910 References and Acknowledgements 911 912 GCC used to stand for the GNU C Compiler, but since the compiler 913 supports several other languages aside from C, it now stands for the 914 GNU Compiler Collection. 915 916 A list of [8]successful builds is updated as new information becomes 917 available. 918 919 The GCC developers would like to thank the numerous people that have 920 contributed new features, improvements, bug fixes, and other changes as 921 well as test results to GCC. This [9]amazing group of volunteers is 922 what makes GCC successful. 923 924 For additional information about GCC please refer to the [10]GCC 925 project web site or contact the [11]GCC development mailing list. 926 927 To obtain GCC please use [12]our mirror sites or [13]our version 928 control system. 929 930 931 For questions related to the use of GCC, please consult these web 932 pages and the [14]GCC manuals. If that fails, the 933 [15]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 934 web pages and the development of GCC are welcome on our developer 935 list at [16]gcc (a] gcc.gnu.org. All of [17]our lists have public 936 archives. 937 938 Copyright (C) [18]Free Software Foundation, Inc. Verbatim copying and 939 distribution of this entire article is permitted in any medium, 940 provided this notice is preserved. 941 942 These pages are [19]maintained by the GCC team. Last modified 943 2020-03-12[20]. 944 945 References 946 947 1. http://www.gnu.org/ 948 2. http://gcc.gnu.org/gcc-9/changes.html 949 3. http://gcc.gnu.org/onlinedocs/9.3.0/ 950 4. http://gcc.gnu.org/gcc-9/changes.html 951 5. http://gcc.gnu.org/onlinedocs/9.2.0/ 952 6. http://gcc.gnu.org/gcc-9/changes.html 953 7. http://gcc.gnu.org/onlinedocs/9.1.0/ 954 8. http://gcc.gnu.org/gcc-9/buildstat.html 955 9. http://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Contributors.html 956 10. http://gcc.gnu.org/index.html 957 11. mailto:gcc (a] gcc.gnu.org 958 12. http://gcc.gnu.org/mirrors.html 959 13. http://gcc.gnu.org/git.html 960 14. https://gcc.gnu.org/onlinedocs/ 961 15. mailto:gcc-help (a] gcc.gnu.org 962 16. mailto:gcc (a] gcc.gnu.org 963 17. https://gcc.gnu.org/lists.html 964 18. https://www.fsf.org/ 965 19. https://gcc.gnu.org/about.html 966 20. http://validator.w3.org/check/referer 967 ====================================================================== 968 http://gcc.gnu.org/gcc-9/changes.html 969 970 GCC 9 Release Series 971 Changes, New Features, and Fixes 972 973 This page is a "brief" summary of some of the huge number of 974 improvements in GCC 9. You may also want to check out our [1]Porting to 975 GCC 9 page and the [2]full GCC documentation. 976 977 Caveats 978 979 * On Arm targets (arm*-*-*), [3]a bug in the implementation of the 980 procedure call standard (AAPCS) in the GCC 6, 7 and 8 releases has 981 been fixed: a structure containing a bit-field based on a 64-bit 982 integral type and where no other element in a structure required 983 64-bit alignment could be passed incorrectly to functions. This is 984 an ABI change. If the option -Wpsabi is enabled (on by default) the 985 compiler will emit a diagnostic note for code that might be 986 affected. 987 * Support for a number of older systems and recently unmaintained or 988 untested target ports of GCC has been declared obsolete in GCC 9. 989 Unless there is activity to revive them, the next release of GCC 990 will have their sources permanently removed. 991 The following ports for individual systems on particular 992 architectures have been obsoleted: 993 + Solaris 10 (*-*-solaris2.10). Details can be found in the 994 [4]announcement. 995 + Cell Broadband Engine SPU (spu*-*-*). Details can be found in 996 the [5]announcement. 997 * A change to the C++ std::rotate algorithm in GCC 9.1.0 can cause 998 ABI incompatibilities with object files compiled with other 999 versions of GCC. If the std::rotate algorithm is called with an 1000 empty range then it might cause a divide-by-zero error (as a SIGFPE 1001 signal) and crash. The change has been reverted for GCC 9.2.0 and 1002 future releases. For more details see [6]Bug 90920. The problem can 1003 be avoided by recompiling any objects that might call std::rotate 1004 with an empty range, so that the GCC 9.1.0 definition of 1005 std::rotate is not used. 1006 * The automatic template instantiation at link time ([7]-frepo) has 1007 been deprecated and will be removed in a future release. 1008 * The --with-default-libstdcxx-abi=gcc4-compatible configure option 1009 is broken in the 9.1 and 9.2 releases, producing a shared library 1010 with missing symbols (see [8]Bug 90361). As a workaround, configure 1011 without that option and build GCC as normal, then edit the 1012 installed <bits/c++config.h> headers to define the 1013 _GLIBCXX_USE_CXX11_ABI macro to 0. 1014 1015 General Improvements 1016 1017 The following GCC command line options have been introduced or 1018 improved. 1019 * All command line options that take a byte-size argument accept 1020 64-bit integers as well as standard SI and IEC suffixes such as kb 1021 and KiB, MB and MiB, or GB and GiB denoting the corresponding 1022 multiples of bytes. See [9]Invoking GCC for more. 1023 * A new option, 1024 [10]-flive-patching=[inline-only-static|inline-clone], has been 1025 introduced to provide a safe compilation for live-patching. At the 1026 same time, provides multiple-level control on the enabled IPA 1027 optimizations. See the user guide for more details about the 1028 option. 1029 * A new option, --completion, has been added to provide more fine 1030 option completion in a shell. It is intended to be used by 1031 Bash-completion. 1032 * GCC's diagnostics now print source code with a left margin showing 1033 line numbers, configurable with 1034 [11]-fno-diagnostics-show-line-numbers. 1035 GCC's diagnostics can also now label regions of the source code to 1036 show pertinent information, such as the types within an expression. 1037 $ g++ t.cc 1038 t.cc: In function 'int test(const shape&, const shape&)': 1039 t.cc:15:4: error: no match for 'operator+' (operand types are 'boxed_value<doubl 1040 e>' and 'boxed_value<double>') 1041 14 | return (width(s1) * height(s1) 1042 | ~~~~~~~~~~~~~~~~~~~~~~ 1043 | | 1044 | boxed_value<[...]> 1045 15 | + width(s2) * height(s2)); 1046 | ^ ~~~~~~~~~~~~~~~~~~~~~~ 1047 | | 1048 | boxed_value<[...]> 1049 1050 These labels can be disabled via [12]-fno-diagnostics-show-labels. 1051 * A new option [13]-fdiagnostics-format=json has been introduced for 1052 emitting diagnostics in a machine-readable format. 1053 * The alignment-related options [14]-falign-functions, 1054 [15]-falign-labels, [16]-falign-loops, and [17]-falign-jumps 1055 received support for a secondary alignment (e.g. 1056 -falign-loops=n:m:n2:m2). 1057 * New pair of profiling options ([18]-fprofile-filter-files and 1058 [19]-fprofile-exclude-files) has been added. The options help to 1059 filter which source files are instrumented. 1060 * AddressSanitizer generates more compact redzones for automatic 1061 variables. That helps to reduce memory footprint of a sanitized 1062 binary. 1063 * Numerous improvements have been made to the output of 1064 [20]-fopt-info. 1065 Messages are now prefixed with optimized, missed, or note, rather 1066 than the old behavior of all being prefixed with note. 1067 The output from -fopt-info can now contain information on inlining 1068 decisions: 1069 $ g++ -c inline.cc -O2 -fopt-info-inline-all 1070 inline.cc:24:11: note: Considering inline candidate void foreach(T, T, void (*)( 1071 E)) [with T = char**; E = char*]/2. 1072 inline.cc:24:11: optimized: Inlining void foreach(T, T, void (*)(E)) [with T = 1073 char**; E = char*]/2 into int main(int, char**)/1. 1074 inline.cc:19:12: missed: not inlinable: void inline_me(char*)/0 -> int std::pu 1075 ts(const char*)/3, function body not available 1076 inline.cc:13:8: optimized: Inlined void inline_me(char*)/4 into int main(int, c 1077 har**)/1 which now has time 127.363637 and size 11, net change of +0. 1078 Unit growth for small function inlining: 16->16 (0%) 1079 1080 Inlined 2 calls, eliminated 1 functions 1081 1082 1083 The output from the vectorizer has been rationalized so that failed 1084 attempts to vectorize a loop are displayed in the form 1085 [LOOP-LOCATION]: couldn't vectorize this loop 1086 [PROBLEM-LOCATION]: because of [REASON] 1087 1088 rather than an exhaustive log of all decisions made by the 1089 vectorizer. For example: 1090 $ gcc -c v.c -O3 -fopt-info-all-vec 1091 v.c:7:3: missed: couldn't vectorize loop 1092 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 1093 mory"); 1094 v.c:3:6: note: vectorized 0 loops in function. 1095 v.c:10:7: missed: statement clobbers memory: __asm__ __volatile__("" : : : "me 1096 mory"); 1097 1098 The old behavior can be obtained via a new -internals suboption of 1099 -fopt-info. 1100 * A new option, [21]-fsave-optimization-record has been added, which 1101 writes a SRCFILE.opt-record.json.gz file describing the 1102 optimization decisions made by GCC. This is similar to the output 1103 of -fopt-info, but with additional metadata such as the inlining 1104 chain, and profile information (if available). 1105 * Inter-procedural propagation of stack alignment can now be 1106 controlled by [22]-fipa-stack-alignment. 1107 * Propagation of addressability, readonly and writeonly flags on 1108 static variables can now be controlled by 1109 [23]-fipa-reference-addressable. 1110 1111 The following built-in functions have been introduced. 1112 * [24]__builtin_expect_with_probability to provide branch prediction 1113 probability hints to the optimizer. 1114 * [25]__builtin_has_attribute determines whether a function, type, or 1115 variable has been declared with some attribute. 1116 * [26]__builtin_speculation_safe_value can be used to help mitigate 1117 against unsafe speculative execution. 1118 1119 The following attributes have been introduced. 1120 * The [27]copy function attribute has been added. The attribute can 1121 also be applied to type definitions and to variable declarations. 1122 1123 A large number of improvements to code generation have been made, 1124 including but not limited to the following. 1125 * Switch expansion has been improved by using a different strategy 1126 (jump table, bit test, decision tree) for a subset of switch cases. 1127 * A linear function expression defined as a switch statement can be 1128 transformed by [28]-ftree-switch-conversion. For example: 1129 1130 int 1131 foo (int how) 1132 { 1133 switch (how) { 1134 case 2: how = 205; break; 1135 case 3: how = 305; break; 1136 case 4: how = 405; break; 1137 case 5: how = 505; break; 1138 case 6: how = 605; break; 1139 } 1140 return how; 1141 } 1142 1143 can be transformed into 100 * how + 5 (for values defined in the 1144 switch statement). 1145 * Inter-procedural optimization improvements: 1146 + Inliner defaults was tuned to better suits modern C++ 1147 codebases especially when built with link time optimizations. 1148 New parameters max-inline-insns-small, max-inline-insns-size, 1149 uninlined-function-insns, uninlined-function-time, 1150 uninlined-thunk-insns, and uninlined-thunk-time were added. 1151 + Hot/cold partitioning is now more precise and aggressive. 1152 + Improved scalability for very large translation units 1153 (especially when link-time optimizing large programs). 1154 * Profile driven optimization improvements: 1155 + [29]-fprofile-use now enables [30]-fversion-loops-for-strides, 1156 [31]-floop-interchange, [32]-floop-unroll-and-jam, 1157 [33]-ftree-loop-distribution. 1158 + Streaming of counter histograms was removed. This reduces the 1159 size of profile files. Histogram is computed on the fly with 1160 link-time optimization. Parameter hot-bb-count-ws-permille was 1161 reduced from 999 to 990 to account for more precise 1162 histograms. 1163 * Link-time optimization improvements: 1164 + Types are now simplified prior streaming resulting in 1165 significant reductions of the LTO object files, link-time 1166 memory use, and improvements of link-time parallelism. 1167 + Default number of partitions (--param lto-partitions) was 1168 increased from 32 to 128 enabling effective use of CPUs with 1169 more than 32 hyperthreads. --param 1170 lto-max-streaming-parallelism can now be used to control 1171 number of streaming processes. 1172 + Warnings on C++ One Decl Rule violations (-Wodr) are now more 1173 informative and produce fewer redundant results. 1174 Overall compile time of Firefox 66 and LibreOffice 6.2.3 on an 1175 8-core machine was reduced by about 5% compared to GCC 8.3, and the 1176 size of LTO object files by 7%. LTO link-time improves by 11% on an 1177 8-core machine and scales significantly better for more parallel 1178 build environments. The serial stage of the link-time optimization 1179 is 28% faster consuming 20% less memory. The parallel stage now 1180 scales to up to 128 partitions rather than 32 and reduces memory 1181 use for every worker by 30%. 1182 1183 The following improvements to the gcov command-line utility have been 1184 made. 1185 * The gcov tool received a new option [34]--use-hotness-colors (-q) 1186 that can provide perf-like coloring of hot functions. 1187 * The gcov tool has changed its intermediate format to a new JSON 1188 format. 1189 1190 New Languages and Language specific improvements 1191 1192 [35]OpenACC support in C, C++, and Fortran continues to be maintained 1193 and improved. Most of the OpenACC 2.5 specification is implemented. See 1194 the [36]implementation status section on the OpenACC wiki page for 1195 further information. 1196 1197 C family 1198 1199 * Version 5.0 of the [37]OpenMP specification is now partially 1200 supported in the C and C++ compilers. For details which features of 1201 OpenMP 5.0 are and which are not supported in the GCC 9 release see 1202 [38]this mail. 1203 * New extensions: 1204 + [39]__builtin_convertvector built-in for vector conversions 1205 has been added. 1206 * New warnings: 1207 + [40]-Waddress-of-packed-member, enabled by default, warns 1208 about an unaligned pointer value from the address of a packed 1209 member of a struct or union. 1210 * Enhancements to existing warnings: 1211 + [41]-Warray-bounds detects more instances of out-of-bounds 1212 indices. 1213 + [42]-Wattribute-alias also detects attribute mismatches 1214 between alias declarations and their targets, in addition to 1215 mismatches between their types. 1216 + [43]-Wformat-overflow and [44]-Wformat-truncation have been 1217 extended to all formatted input/output functions (where 1218 applicable) and enhanced to detect a subset of instances of 1219 reading past the end of unterminated constant character arrays 1220 in %s directives. 1221 + [45]-Wmissing-attributes detects instances of missing function 1222 attributes on declarations of aliases and weak references. 1223 + [46]-Wstringop-truncation also detects a subset of instances 1224 of reading past the end of unterminated constant character 1225 arrays, 1226 * If a macro is used with the wrong argument count, the C and C++ 1227 front ends now show the definition of that macro via a note. 1228 * The spelling corrector now considers transposed letters, and the 1229 threshold for similarity has been tightened, to avoid nonsensical 1230 suggestions. 1231 1232 C 1233 1234 * There is now experimental support for -std=c2x, to select support 1235 for the upcoming C2X revision of the ISO C standard. This standard 1236 is in the early stages of development and the only feature 1237 supported in GCC 9 is _Static_assert with a single argument 1238 (support for _Static_assert with two arguments was added in C11 and 1239 GCC 4.6). There are also new options -std=gnu2x, for C2X with GNU 1240 extensions, and -Wc11-c2x-compat, to warn for uses of features 1241 added in C2X (such warnings are also enabled by use of -Wpedantic 1242 if not using -std=c2x or -std=gnu2x). 1243 * New warnings: 1244 + [47]-Wabsolute-value warns for calls to standard functions 1245 that compute the absolute value of an argument when a more 1246 appropriate standard function is available. For example, 1247 calling abs(3.14) triggers the warning because the appropriate 1248 function to call to compute the absolute value of a double 1249 argument is fabs. The option also triggers warnings when the 1250 argument in a call to such a function has an unsigned type. 1251 This warning can be suppressed with an explicit type cast and 1252 it is also enabled by -Wextra. 1253 1254 C++ 1255 1256 * New warnings: 1257 + [48]-Wdeprecated-copy, implied by -Wextra, warns about the 1258 C++11 deprecation of implicitly declared copy constructor and 1259 assignment operator if one of them is user-provided. 1260 -Wdeprecated-copy-dtor also warns if the destructor is 1261 user-provided, as specified in C++11. 1262 + [49]-Winit-list-lifetime, on by default, warns about uses of 1263 std::initializer_list that are likely to result in a dangling 1264 pointer, such as returning or assigning from a temporary list. 1265 + [50]-Wredundant-move, implied by -Wextra, warns about 1266 redundant calls to std::move. 1267 + [51]-Wpessimizing-move, implied by -Wall, warns when a call to 1268 std::move prevents copy elision. 1269 + [52]-Wclass-conversion, on by default, warns when a conversion 1270 function will never be called due to the type it converts to. 1271 * The C++ front end has experimental support for some of the upcoming 1272 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 1273 including range-based for statements with initializer, default 1274 constructible and assignable stateless lambdas, lambdas in 1275 unevaluated contexts, language support for empty data members, 1276 allowing pack expansion in lambda init-capture, likely and unlikely 1277 attributes, class types in non-type template parameters, allowing 1278 virtual function calls in constant expressions, explicit(bool), 1279 std::is_constant_evaluated, nested inline namespaces, etc. For a 1280 full list of new features, see [53]the C++ status page. 1281 * The C++ front end now preserves source locations for literals, 1282 id-expression, and mem-initializer for longer. For example it is 1283 now able to pin-point the pertinent locations for bad 1284 initializations such as these 1285 $ g++ -c bad-inits.cc 1286 bad-inits.cc:10:14: error: cannot convert 'json' to 'int' in initialization 1287 10 | { 3, json::object }, 1288 | ~~~~~~^~~~~~ 1289 | | 1290 | json 1291 bad-inits.cc:14:31: error: initializer-string for array of chars is too long [-f 1292 permissive] 1293 14 | char buffers[3][5] = { "red", "green", "blue" }; 1294 | ^~~~~~~ 1295 bad-inits.cc: In constructor 'X::X()': 1296 bad-inits.cc:17:13: error: invalid conversion from 'int' to 'void*' [-fpermissiv 1297 e] 1298 17 | X() : one(42), two(42), three(42) 1299 | ^~ 1300 | | 1301 | int 1302 1303 rather than emitting the error at the final closing parenthesis or 1304 brace. 1305 * Error-reporting of overload resolution has been special-cased to 1306 make the case of a single failed candidate easier to read. For 1307 example: 1308 $ g++ param-type-mismatch.cc 1309 param-type-mismatch.cc: In function 'int test(int, const char*, float)': 1310 param-type-mismatch.cc:8:32: error: cannot convert 'const char*' to 'const char* 1311 *' 1312 8 | return foo::member_1 (first, second, third); 1313 | ^~~~~~ 1314 | | 1315 | const char* 1316 param-type-mismatch.cc:3:46: note: initializing argument 2 of 'static int foo: 1317 :member_1(int, const char**, float)' 1318 3 | static int member_1 (int one, const char **two, float three); 1319 | ~~~~~~~~~~~~~^~~ 1320 1321 highlights both the problematic argument, and the parameter that it 1322 can't be converted to. 1323 * Diagnostics involving binary operators now use color to distinguish 1324 the two operands, and label them separately (as per the example of 1325 source labelling above). 1326 * Diagnostics involving function calls now highlight the pertinent 1327 parameter of the declaration in more places. 1328 $ g++ bad-conversion.cc 1329 bad-conversion.cc: In function 'void caller()': 1330 bad-conversion.cc:9:14: error: cannot convert 'bool' to 'void*' 1331 9 | callee (0, false, 2); 1332 | ^~~~~ 1333 | | 1334 | bool 1335 bad-conversion.cc:3:19: note: initializing argument 2 of 'void callee(int, voi 1336 d*, int)' 1337 3 | void callee (int, void *, int) 1338 | ^~~~~~ 1339 1340 * The C++ front end's implementation of [54]-Wformat now shows 1341 precise locations within string literals, and underlines the 1342 pertinent arguments at bogus call sites (the C front end has been 1343 doing this since GCC 7). For example: 1344 $ g++ -c bad-printf.cc -Wall 1345 bad-printf.cc: In function 'void print_field(const char*, float, long int, long 1346 int)': 1347 bad-printf.cc:6:17: warning: field width specifier '*' expects argument of type 1348 'int', but argument 3 has type 'long int' [-Wformat=] 1349 6 | printf ("%s: %*ld ", fieldname, column - width, value); 1350 | ~^~~ ~~~~~~~~~~~~~~ 1351 | | | 1352 | int long int 1353 bad-printf.cc:6:19: warning: format '%ld' expects argument of type 'long int', b 1354 ut argument 4 has type 'double' [-Wformat=] 1355 6 | printf ("%s: %*ld ", fieldname, column - width, value); 1356 | ~~~^ ~~~~~ 1357 | | | 1358 | long int double 1359 | %*f 1360 1361 * The C++ front end has gained new fix-it hints for forgetting the 1362 return *this; needed by various C++ operators: 1363 $ g++ -c operator.cc 1364 operator.cc: In member function 'boxed_ptr& boxed_ptr::operator=(const boxed_ptr 1365 &)': 1366 operator.cc:7:3: warning: no return statement in function returning non-void [-W 1367 return-type] 1368 6 | m_ptr = other.m_ptr; 1369 +++ |+ return *this; 1370 7 | } 1371 | ^ 1372 1373 for when the compiler needs a typename: 1374 $ g++ -c template.cc 1375 template.cc:3:3: error: need 'typename' before 'Traits::type' because 'Traits' i 1376 s a dependent scope 1377 3 | Traits::type type; 1378 | ^~~~~~ 1379 | typename 1380 1381 when trying to use an accessor member as if it were a data member: 1382 $ g++ -c fncall.cc 1383 fncall.cc: In function 'void hangman(const mystring&)': 1384 fncall.cc:12:11: error: invalid use of member function 'int mystring::get_length 1385 () const' (did you forget the '()' ?) 1386 12 | if (str.get_length > 0) 1387 | ~~~~^~~~~~~~~~ 1388 | () 1389 1390 for C++11's scoped enums: 1391 $ g++ -c enums.cc 1392 enums.cc: In function 'void json::test(const json::value&)': 1393 enums.cc:12:26: error: 'STRING' was not declared in this scope; did you mean 'js 1394 on::kind::STRING'? 1395 12 | if (v.get_kind () == STRING) 1396 | ^~~~~~ 1397 | json::kind::STRING 1398 enums.cc:3:44: note: 'json::kind::STRING' declared here 1399 3 | enum class kind { OBJECT, ARRAY, NUMBER, STRING, TRUE, FALSE, NULL_ }; 1400 | ^~~~~~ 1401 1402 and a tweak to integrate the suggestions about misspelled members 1403 with that for accessors: 1404 $ g++ -c accessor-fixit.cc 1405 accessor-fixit.cc: In function 'int test(t*)': 1406 accessor-fixit.cc:17:15: error: 'class t' has no member named 'ratio'; did you m 1407 ean 'int t::m_ratio'? (accessible via 'int t::get_ratio() const') 1408 17 | return ptr->ratio; 1409 | ^~~~~ 1410 | get_ratio() 1411 1412 In addition, various diagnostics in the C++ front-end have been 1413 streamlined by consolidating the suggestion into the initial error, 1414 rather than emitting a follow-up note: 1415 $ g++ typo.cc 1416 typo.cc:5:13: error: 'BUFSIZE' was not declared in this scope; did you mean 'BUF 1417 _SIZE'? 1418 5 | uint8_t buf[BUFSIZE]; 1419 | ^~~~~~~ 1420 | BUF_SIZE 1421 1422 Runtime Library (libstdc++) 1423 1424 * Improved support for C++17, including: 1425 + The C++17 implementation is no longer experimental. 1426 + Parallel algorithms and <execution> (requires [55]Thread 1427 Building Blocks 2018 or newer). 1428 + <memory_resource>. 1429 + Using the types and functions in <filesystem> does not require 1430 linking with -lstdc++fs now. 1431 * Improved experimental support for C++2a, including: 1432 + Type traits std::remove_cvref, std::unwrap_reference, 1433 std::unwrap_decay_ref, std::is_nothrow_convertible, and 1434 std::type_identity. 1435 + Headers <bit> and <version>. 1436 + Uniform container erasure (std::erase_if). 1437 + contains member of maps and sets. 1438 + String prefix and suffix checking (starts_with, ends_with). 1439 + Functions std::midpoint and std::lerp for interpolation. 1440 + std::bind_front. 1441 + std::visit<R>. 1442 + std::assume_aligned. 1443 + Uses-allocator construction utilities. 1444 + std::pmr::polymorphic_allocator<std::byte>. 1445 + Library support for char8_t type. 1446 + Destroying delete. 1447 + std::is_constant_evaluated() function. 1448 * Support for opening file streams with wide character paths on 1449 Windows 1450 * Incomplete support for the C++17 Filesystem library and the 1451 Filesystem TS on Windows. 1452 * Incomplete, experimental support for the Networking TS. 1453 1454 D 1455 1456 * Support for the D programming language has been added to GCC, 1457 implementing version 2.076 of the language and run-time library. 1458 1459 Fortran 1460 1461 * Asynchronous I/O is now fully supported. The program needs to be 1462 linked against the pthreads library to use it, otherwise the I/O is 1463 done synchronously. For systems which do not support POSIX 1464 condition variables, such as AIX, all I/O is still done 1465 synchronously. 1466 * The BACK argument for MINLOC and MAXLOC has been implemented. 1467 * The FINDLOC intrinsic function has been implemented. 1468 * The IS_CONTIGUOUS intrinsic function has been implemented. 1469 * Direct access to the real and imaginary parts of a complex variable 1470 via c%re and c%im has been implemented. 1471 * Type parameter inquiry via str%len and a%kind has been implemented. 1472 * C descriptors and the ISO_Fortran_binding.h source file have been 1473 implemented. 1474 * The MAX and MIN intrinsics are no longer guaranteed to return any 1475 particular value in case one of the arguments is a NaN. Note that 1476 this conforms to the Fortran standard and to what other Fortran 1477 compilers do. If there is a need to handle that case in some 1478 specific way, one needs to explicitly check for NaN's before 1479 calling MAX or MIN, e.g. by using the IEEE_IS_NAN function from the 1480 intrinsic module IEEE_ARITHMETIC. 1481 * A new command-line option [56]-fdec-include, set also by the 1482 [57]-fdec option, has been added to increase compatibility with 1483 legacy code. With this option, an INCLUDE directive is also parsed 1484 as a statement, which allows the directive to be spread across 1485 multiple source lines with line continuations. 1486 * A new [58]BUILTIN directive, has been added. The purpose of the 1487 directive is to provide an API between the GCC compiler and the GNU 1488 C Library which would define vector implementations of math 1489 routines. 1490 1491 Go 1492 1493 * GCC 9 provides a complete implementation of the Go 1.12.2 user 1494 packages. 1495 1496 libgccjit 1497 1498 * The libgccjit API gained a new entry point: 1499 [59]gcc_jit_context_add_driver_option. 1500 1501 New Targets and Target Specific Improvements 1502 1503 AArch64 & Arm 1504 1505 * Support has been added for the following processors (GCC 1506 identifiers in parentheses): 1507 + Arm Cortex-A76 (cortex-a76). 1508 + Arm Cortex-A55/Cortex-A76 DynamIQ big.LITTLE 1509 (cortex-a76.cortex-a55). 1510 + Arm Neoverse N1 (neoverse-n1). 1511 The GCC identifiers can be used as arguments to the -mcpu or -mtune 1512 options, for example: -mcpu=cortex-a76 or 1513 -mtune=cortex-a76.cortex-a55 or as arguments to the equivalent 1514 target attributes and pragmas. 1515 * The Armv8.3-A complex number instructions are now supported via 1516 intrinsics when the option -march=armv8.3-a or equivalent is 1517 specified. For the half-precision floating-point variants of these 1518 instructions use the architecture extension flag +fp16, e.g. 1519 -march=armv8.3-a+fp16. 1520 The intrinsics are defined by the ACLE specification. 1521 * The Armv8.5-A architecture is now supported through the 1522 -march=armv8.5-a option. 1523 * The Armv8.5-A architecture also adds some security features that 1524 are optional to all older architecture versions. These are now 1525 supported and only affect the assembler. 1526 + Speculation Barrier instruction through the -march=armv8-a+sb 1527 option. 1528 + Execution and Data Prediction Restriction instructions through 1529 the -march=armv8-a+predres option. 1530 + Speculative Store Bypass Safe instruction through the 1531 -march=armv8-a+ssbs option. This does not require a compiler 1532 option for Arm and thus -march=armv8-a+ssbs is an 1533 AArch64-specific option. 1534 1535 AArch64 specific 1536 1537 * Support has been added for the Arm Neoverse E1 processor 1538 (-mcpu=neoverse-e1). 1539 * The AArch64 port now has support for stack clash protection using 1540 the [60]-fstack-clash-protection option. The probing interval/guard 1541 size can be set by using --param 1542 stack-clash-protection-guard-size=12|16. The value of this 1543 parameter must be in bytes represented as a power of two. The two 1544 supported values for this parameter are 12 (for a 4KiB size, 2^12) 1545 and 16 (for a 64KiB size, 2^16). The default value is 16 (64Kb) and 1546 can be changed at configure time using the flag 1547 --with-stack-clash-protection-guard-size=12|16. 1548 * The option -msign-return-address= has been deprecated. This has 1549 been replaced by the new -mbranch-protection= option. This new 1550 option can now be used to enable the return address signing as well 1551 as the new Branch Target Identification feature of Armv8.5-A 1552 architecture. For more information on the arguments accepted by 1553 this option, please refer to [61]AArch64-Options. 1554 * The following optional extensions to Armv8.5-A architecture are now 1555 supported and only affect the assembler. 1556 + Random Number Generation instructions through the 1557 -march=armv8.5-a+rng option. 1558 + Memory Tagging Extension through the -march=armv8.5-a+memtag 1559 option. 1560 1561 Arm specific 1562 1563 * Support for the deprecated Armv2 and Armv3 architectures and their 1564 variants has been removed. Their corresponding -march values and 1565 the -mcpu options that used these architectures have been removed. 1566 * Support for the Armv5 and Armv5E architectures (which have no known 1567 implementations) has been removed. Note that Armv5T, Armv5TE and 1568 Armv5TEJ architectures remain supported. 1569 * Corrected FPU configurations for Cortex-R7 and Cortex-R8 when using 1570 their respective -mcpu options. 1571 1572 AMD GCN 1573 1574 * A new back end targeting AMD GCN GPUs has been contributed to GCC. 1575 The implementation is currently limited to compiling 1576 single-threaded, stand-alone programs. Future versions will add 1577 support for offloading multi-threaded kernels via OpenMP and 1578 OpenACC. The following devices are supported (GCC identifiers in 1579 parentheses): 1580 + Fiji (fiji). 1581 + Vega 10 (gfx900). 1582 1583 ARC 1584 1585 * LRA is now on by default for the ARC target. This can be controlled 1586 by -mlra. 1587 * Add support for frame code-density and branch-and-index 1588 instructions. 1589 1590 C-SKY 1591 1592 * A new back end targeting C-SKY V2 processors has been contributed 1593 to GCC. 1594 1595 IA-32/x86-64 1596 1597 * Support of Intel MPX (Memory Protection Extensions) has been 1598 removed. 1599 * New ISA extension support for Intel PTWRITE was added to GCC. 1600 PTWRITE intrinsics are available via the -mptwrite compiler switch. 1601 * GCC now supports the Intel CPU named Cascade Lake with AVX512 1602 extensions through -march=cascadelake. The switch enables the 1603 following ISA extensions: AVX512F, AVX512VL, AVX512CD, AVX512BW, 1604 AVX512DQ, AVX512VNNI. 1605 1606 OpenRISC 1607 1608 * A new back end targeting OpenRISC processors has been contributed 1609 to GCC. 1610 1611 S/390, System z, IBM z Systems 1612 1613 * Support for the arch13 architecture has been added. When using the 1614 -march=arch13 option, the compiler will generate code making use of 1615 the new instructions introduced with the vector enhancement 1616 facility 2 and the miscellaneous instruction extension facility 2. 1617 The -mtune=arch13 option enables arch13 specific instruction 1618 scheduling without making use of new instructions. 1619 * Builtins for the new vector instructions have been added and can be 1620 enabled using the -mzvector option. 1621 * Support for ESA architecture machines g5 and g6 is deprecated since 1622 GCC 6.1.0 and has been removed now. 1623 * When compiling with -march=z14 or higher GCC emits alignments hints 1624 on the vector load/store instructions (8 or 16 byte). 1625 * Functions now have a default alignment of 16 bytes. This helps with 1626 branch prediction effects. 1627 * -mfentry is now supported. As well as the mcount mechanism the 1628 __fentry__ is called before the function prologue. However, since 1629 just a single instruction is required to call __fentry__ the call 1630 sequence imposes a smaller overhead than mcount (4 instructions). 1631 The produced code is compatible only with newer glibc versions, 1632 which provide the __fentry__ symbol and do not clobber r0 when 1633 resolving lazily bound functions. -mfentry is only supported when 1634 generating 64 bit code and does not work with nested C functions. 1635 * The -mnop-mcount option can be used to emit NOP instructions 1636 instead of an mcount or fentry call stub. 1637 * With the -mrecord-mcount option a __mcount_loc section is generated 1638 containing pointers to each profiling call stub. This is useful for 1639 automatically patching in and out calls. 1640 1641 Operating Systems 1642 1643 Solaris 1644 1645 * g++ now unconditionally enables large file support when compiling 1646 32-bit code. 1647 * Support for the AddressSanitizer and UndefinedBehaviorSanitizer has 1648 been merged from LLVM. For the moment, this only works for 32-bit 1649 code on both SPARC and x86. 1650 * An initial port of the D runtime library has been completed on 1651 Solaris 11/x86. It requires the use of GNU as. Solaris 11/SPARC 1652 support is still work-in-progress. 1653 1654 Windows 1655 1656 * A C++ Microsoft ABI bitfield layout bug, [62]PR87137 has been 1657 fixed. A non-field declaration could cause the current bitfield 1658 allocation unit to be completed, incorrectly placing a following 1659 bitfield into a new allocation unit. The Microsoft ABI is selected 1660 for: 1661 + Mingw targets 1662 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 1663 option is specified, or __attribute__((ms_struct)) is used 1664 + SuperH targets when the -mhitachi option is specified, or 1665 __attribute__((renesas)) is used 1666 1667 Improvements for plugin authors 1668 1669 * GCC's diagnostic subsystem now has a way to logically group 1670 together related diagnostics, auto_diagnostic_group. Such 1671 diagnostics will be nested by the output of 1672 [63]-fdiagnostics-format=json. 1673 * GCC now has a set of [64]user experience guidelines for GCC, with 1674 information and advice on implementing new diagnostics. 1675 1676 Other significant improvements 1677 1678 * GCC's internal "selftest" suite now runs for C++ as well as C (in 1679 debug builds of the compiler). 1680 1681 GCC 9.1 1682 1683 This is the [65]list of problem reports (PRs) from GCC's bug tracking 1684 system that are known to be fixed in the 9.1 release. This list might 1685 not be complete (that is, it is possible that some PRs that have been 1686 fixed are not listed here). 1687 1688 GCC 9.2 1689 1690 This is the [66]list of problem reports (PRs) from GCC's bug tracking 1691 system that are known to be fixed in the 9.2 release. This list might 1692 not be complete (that is, it is possible that some PRs that have been 1693 fixed are not listed here). 1694 1695 GCC 9.3 1696 1697 This is the [67]list of problem reports (PRs) from GCC's bug tracking 1698 system that are known to be fixed in the 9.3 release. This list might 1699 not be complete (that is, it is possible that some PRs that have been 1700 fixed are not listed here). 1701 1702 GCC 9.4 1703 1704 Target Specific Changes 1705 1706 AArch64 1707 1708 * The option -moutline-atomics has been added to aid deployment of 1709 the Large System Extensions (LSE) on GNU/Linux systems built with a 1710 baseline architecture targeting Armv8-A. When the option is 1711 specified code is emitted to detect the presence of LSE 1712 instructions at run time and use them for standard atomic 1713 operations. For more information please refer to the documentation. 1714 * GCC now supports the Fujitsu A64FX. The associated -mcpu and -mtune 1715 options are -mcpu=a64fx and -mtune=a64fx respectively. In 1716 particular, -mcpu=a64fx generates code for Armv8.2-A with SVE and 1717 tunes the code for the A64FX. This includes tuning the SVE code, 1718 although by default the code is still length-agnostic and so works 1719 for all SVE implementations. Adding -msve-vector-bits=512 makes the 1720 code specific to 512-bit SVE. 1721 1722 1723 For questions related to the use of GCC, please consult these web 1724 pages and the [68]GCC manuals. If that fails, the 1725 [69]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1726 web pages and the development of GCC are welcome on our developer 1727 list at [70]gcc (a] gcc.gnu.org. All of [71]our lists have public 1728 archives. 1729 1730 Copyright (C) [72]Free Software Foundation, Inc. Verbatim copying and 1731 distribution of this entire article is permitted in any medium, 1732 provided this notice is preserved. 1733 1734 These pages are [73]maintained by the GCC team. Last modified 1735 2021-03-28[74]. 1736 1737 References 1738 1739 1. http://gcc.gnu.org/gcc-9/porting_to.html 1740 2. http://gcc.gnu.org/onlinedocs/index.html#current 1741 3. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88469 1742 4. https://gcc.gnu.org/ml/gcc/2018-10/msg00139.html 1743 5. https://gcc.gnu.org/ml/gcc/2019-04/msg00023.html 1744 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90920 1745 7. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/C_002b_002b-Dialect-Options.html#index-frepo 1746 8. https://gcc.gnu.org/PR90361 1747 9. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-GCC.html#Invoking-GCC 1748 10. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-flive-patching 1749 11. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-line-numbers 1750 12. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fno-diagnostics-show-labels 1751 13. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Diagnostic-Message-Formatting-Options.html#index-fdiagnostics-format 1752 14. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-falign-functions 1753 15. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-falign-labels 1754 16. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-falign-loops 1755 17. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-falign-jumps 1756 18. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Instrumentation-Options.html#index-fprofile-filter-files 1757 19. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Instrumentation-Options.html#index-fprofile-exclude-files 1758 20. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Developer-Options.html#index-fopt-info 1759 21. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Developer-Options.html#index-fsave-optimization-record 1760 22. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fipa-stack-alignment 1761 23. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fipa-reference-addressable 1762 24. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fexpect_005fwith_005fprobability 1763 25. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fhas_005fattribute-1 1764 26. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fspeculation_005fsafe_005fvalue-1 1765 27. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Common-Function-Attributes.html#index-copy-function-attribute 1766 28. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-ftree-switch-conversion 1767 29. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fprofile-use 1768 30. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-fversion-loops-for-strides 1769 31. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-interchange 1770 32. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-floop-unroll-and-jam 1771 33. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Optimize-Options.html#index-ftree-loop-distribution 1772 34. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Invoking-Gcov.html#Invoking-Gcov 1773 35. https://www.openacc.org/ 1774 36. https://gcc.gnu.org/wiki/OpenACC#status-9 1775 37. https://www.openmp.org/specifications/ 1776 38. https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00628.html 1777 39. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Vector-Extensions.html#index-_005f_005fbuiltin_005fconvertvector 1778 40. https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Warning-Options.html#index-Waddress-of-packed-member 1779 41. 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https://gcc.gnu.org/about.html 1812 74. http://validator.w3.org/check/referer 1813 ====================================================================== 1814 http://gcc.gnu.org/gcc-8/index.html 1815 1816 GCC 8 Release Series 1817 1818 Mar 4, 2020 1819 1820 The [1]GNU project and the GCC developers are pleased to announce the 1821 release of GCC 8.4. 1822 1823 This release is a bug-fix release, containing fixes for regressions in 1824 GCC 8.3 relative to previous releases of GCC. 1825 1826 Release History 1827 1828 GCC 8.4 1829 Mar 4, 2020 ([2]changes, [3]documentation) 1830 1831 GCC 8.3 1832 Feb 22, 2019 ([4]changes, [5]documentation) 1833 1834 GCC 8.2 1835 Jul 26, 2018 ([6]changes, [7]documentation) 1836 1837 GCC 8.1 1838 May 2, 2018 ([8]changes, [9]documentation) 1839 1840 References and Acknowledgements 1841 1842 GCC used to stand for the GNU C Compiler, but since the compiler 1843 supports several other languages aside from C, it now stands for the 1844 GNU Compiler Collection. 1845 1846 A list of [10]successful builds is updated as new information becomes 1847 available. 1848 1849 The GCC developers would like to thank the numerous people that have 1850 contributed new features, improvements, bug fixes, and other changes as 1851 well as test results to GCC. This [11]amazing group of volunteers is 1852 what makes GCC successful. 1853 1854 For additional information about GCC please refer to the [12]GCC 1855 project web site or contact the [13]GCC development mailing list. 1856 1857 To obtain GCC please use [14]our mirror sites or [15]our version 1858 control system. 1859 1860 1861 For questions related to the use of GCC, please consult these web 1862 pages and the [16]GCC manuals. If that fails, the 1863 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 1864 web pages and the development of GCC are welcome on our developer 1865 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 1866 archives. 1867 1868 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 1869 distribution of this entire article is permitted in any medium, 1870 provided this notice is preserved. 1871 1872 These pages are [21]maintained by the GCC team. Last modified 1873 2020-03-04[22]. 1874 1875 References 1876 1877 1. http://www.gnu.org/ 1878 2. http://gcc.gnu.org/gcc-8/changes.html 1879 3. http://gcc.gnu.org/onlinedocs/8.4.0/ 1880 4. http://gcc.gnu.org/gcc-8/changes.html 1881 5. http://gcc.gnu.org/onlinedocs/8.3.0/ 1882 6. http://gcc.gnu.org/gcc-8/changes.html 1883 7. http://gcc.gnu.org/onlinedocs/8.2.0/ 1884 8. http://gcc.gnu.org/gcc-8/changes.html 1885 9. http://gcc.gnu.org/onlinedocs/8.1.0/ 1886 10. http://gcc.gnu.org/gcc-8/buildstat.html 1887 11. http://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Contributors.html 1888 12. http://gcc.gnu.org/index.html 1889 13. mailto:gcc (a] gcc.gnu.org 1890 14. http://gcc.gnu.org/mirrors.html 1891 15. http://gcc.gnu.org/git.html 1892 16. https://gcc.gnu.org/onlinedocs/ 1893 17. mailto:gcc-help (a] gcc.gnu.org 1894 18. mailto:gcc (a] gcc.gnu.org 1895 19. https://gcc.gnu.org/lists.html 1896 20. https://www.fsf.org/ 1897 21. https://gcc.gnu.org/about.html 1898 22. http://validator.w3.org/check/referer 1899 ====================================================================== 1900 http://gcc.gnu.org/gcc-8/changes.html 1901 1902 GCC 8 Release Series 1903 Changes, New Features, and Fixes 1904 1905 This page is a "brief" summary of some of the huge number of 1906 improvements in GCC 8. You may also want to check out our [1]Porting to 1907 GCC 8 page and the [2]full GCC documentation. 1908 1909 Caveats 1910 1911 * Support for the obsolete SDB/coff debug info format has been 1912 removed. The option -gcoff no longer does anything. 1913 * The Cilk+ extensions to the C and C++ languages have been removed. 1914 * The MPX extensions to the C and C++ languages have been deprecated 1915 and will be removed in a future release. 1916 * The extension allowing arithmetic on std::atomic<void*> and types 1917 like std::atomic<R(*)()> has been deprecated. 1918 * The non-standard C++0x std::copy_exception function was removed. 1919 std::make_exception_ptr should be used instead. 1920 * Support for the powerpc*-*-*spe* target ports which have been 1921 recently unmaintained and untested in GCC has been declared 1922 obsolete in GCC 8 as [3]announced. Unless there is activity to 1923 revive them, the next release of GCC will have their sources 1924 permanently removed. 1925 1926 General Improvements 1927 1928 * Inter-procedural optimization improvements: 1929 + Reworked run-time estimation metrics leading to more realistic 1930 guesses driving inliner and cloning heuristics. 1931 + The ipa-pure-const pass is extended to propagate the malloc 1932 attribute, and the corresponding warning option 1933 -Wsuggest-attribute=malloc emits a diagnostic for functions 1934 which can be annotated with the malloc attribute. 1935 * Profile driven optimization improvements: 1936 + New infrastructure for representing profiles (both statically 1937 guessed and profile feedback) which allows propagation of 1938 additional information about the reliability of the profile. 1939 + A number of improvements in the profile updating code solving 1940 problems found by new verification code. 1941 + Static detection of code which is not executed in a valid run 1942 of the program. This includes paths which trigger undefined 1943 behavior as well as calls to functions declared with the cold 1944 attribute. Newly the noreturn attribute does not imply all 1945 effects of cold to differentiate between exit (which is 1946 noreturn) and abort (which is in addition not executed in 1947 valid runs). 1948 + -freorder-blocks-and-partition, a pass splitting function 1949 bodies into hot and cold regions, is now enabled by default at 1950 -O2 and higher for x86 and x86-64. 1951 * Link-time optimization improvements: 1952 + We have significantly improved debug information on ELF 1953 targets using DWARF by properly preserving language-specific 1954 information. This allows for example the libstdc++ 1955 pretty-printers to work with LTO optimized executables. 1956 * A new option -fcf-protection=[full|branch|return|none] is 1957 introduced to perform code instrumentation to increase program 1958 security by checking that target addresses of control-flow transfer 1959 instructions (such as indirect function call, function return, 1960 indirect jump) are valid. Currently the instrumentation is 1961 supported on x86 GNU/Linux targets only. See the user guide for 1962 further information about the option syntax and section "New 1963 Targets and Target Specific Improvements" for IA-32/x86-64 for more 1964 details. 1965 * The -gcolumn-info option is now enabled by default. It includes 1966 column information in addition to just filenames and line numbers 1967 in DWARF debugging information. 1968 * The polyhedral-based loop nest optimization pass 1969 -floop-nest-optimize has been overhauled. It's still considered 1970 experimental and may not result in any runtime improvements. 1971 * Two new classical loop nest optimization passes have been added. 1972 -floop-unroll-and-jam performs outer loop unrolling and fusing of 1973 the inner loop copies. -floop-interchange exchanges loops in a loop 1974 nest to improve data locality. Both passes are enabled by default 1975 at -O3 and above. 1976 * The classic loop nest optimization pass -ftree-loop-distribution 1977 has been improved and enabled by default at -O3 and above. It 1978 supports loop nest distribution in some restricted scenarios; it 1979 also supports cancellable innermost loop distribution with loop 1980 versioning under run-time alias checks. 1981 * The new option -fstack-clash-protection causes the compiler to 1982 insert probes whenever stack space is allocated statically or 1983 dynamically to reliably detect stack overflows and thus mitigate 1984 the attack vector that relies on jumping over a stack guard page as 1985 provided by the operating system. 1986 * A new pragma GCC unroll has been implemented in the C family of 1987 languages, as well as Fortran and Ada, so as to make it possible 1988 for the user to have a finer-grained control over the loop 1989 unrolling optimization. 1990 * GCC has been enhanced to detect more instances of meaningless or 1991 mutually exclusive attribute specifications and handle such 1992 conflicts more consistently. Mutually exclusive attribute 1993 specifications are ignored with a warning regardless of whether 1994 they appear on the same declaration or on distinct declarations of 1995 the same entity. For example, because the noreturn attribute on the 1996 second declaration below is mutually exclusive with the malloc 1997 attribute on the first, it is ignored and a warning is issued. 1998 > 1999 void* __attribute__ ((malloc)) f (unsigned); 2000 void* __attribute__ ((noreturn)) f (unsigned); 2001 2002 warning: ignoring attribute 'noreturn' because it conflicts with attribute 2003 'malloc' [-Wattributes] 2004 * The gcov tool can distinguish functions that begin on a same line 2005 in a source file. This can be a different template instantiation or 2006 a class constructor: 2007 2008 File 'ins.C' 2009 Lines executed:100.00% of 8 2010 Creating 'ins.C.gcov' 2011 2012 -: 0:Source:ins.C 2013 -: 0:Graph:ins.gcno 2014 -: 0:Data:ins.gcda 2015 -: 0:Runs:1 2016 -: 0:Programs:1 2017 -: 1:template<class T> 2018 -: 2:class Foo 2019 -: 3:{ 2020 -: 4: public: 2021 2: 5: Foo(): b (1000) {} 2022 ------------------ 2023 Foo<char>::Foo(): 2024 1: 5: Foo(): b (1000) {} 2025 ------------------ 2026 Foo<int>::Foo(): 2027 1: 5: Foo(): b (1000) {} 2028 ------------------ 2029 2: 6: void inc () { b++; } 2030 ------------------ 2031 Foo<char>::inc(): 2032 1: 6: void inc () { b++; } 2033 ------------------ 2034 Foo<int>::inc(): 2035 1: 6: void inc () { b++; } 2036 ------------------ 2037 -: 7: 2038 -: 8: private: 2039 -: 9: int b; 2040 -: 10:}; 2041 -: 11: 2042 1: 12:int main(int argc, char **argv) 2043 -: 13:{ 2044 1: 14: Foo<int> a; 2045 1: 15: Foo<char> b; 2046 -: 16: 2047 1: 17: a.inc (); 2048 1: 18: b.inc (); 2049 1: 19:} 2050 2051 * The gcov tool has more accurate numbers for execution of lines in a 2052 source file. 2053 * The gcov tool can use TERM colors to provide more readable output. 2054 * AddressSanitizer gained a new pair of sanitization options, 2055 -fsanitize=pointer-compare and -fsanitize=pointer-subtract, which 2056 warn about subtraction (or comparison) of pointers that point to a 2057 different memory object: 2058 2059 int 2060 main () 2061 { 2062 /* Heap allocated memory. */ 2063 char *heap1 = (char *)__builtin_malloc (42); 2064 char *heap2 = (char *)__builtin_malloc (42); 2065 if (heap1 > heap2) 2066 return 1; 2067 2068 return 0; 2069 } 2070 2071 ==17465==ERROR: AddressSanitizer: invalid-pointer-pair: 0x604000000010 0x6040000 2072 00050 2073 #0 0x40070f in main /tmp/pointer-compare.c:7 2074 #1 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2075 #2 0x400629 in _start (/tmp/a.out+0x400629) 2076 2077 0x604000000010 is located 0 bytes inside of 42-byte region [0x604000000010,0x604 2078 00000003a) 2079 allocated by thread T0 here: 2080 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 2081 _malloc_linux.cc:86 2082 #1 0x4006ea in main /tmp/pointer-compare.c:5 2083 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2084 2085 0x604000000050 is located 0 bytes inside of 42-byte region [0x604000000050,0x604 2086 00000007a) 2087 allocated by thread T0 here: 2088 #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan 2089 _malloc_linux.cc:86 2090 #1 0x4006f8 in main /tmp/pointer-compare.c:6 2091 #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86) 2092 2093 SUMMARY: AddressSanitizer: invalid-pointer-pair /tmp/pointer-compare.c:7 in main 2094 2095 * The store merging pass has been enhanced to handle bit-fields and 2096 not just constant stores, but also data copying from adjacent 2097 memory locations into other adjacent memory locations, including 2098 bitwise logical operations on the data. The pass can also handle 2099 byte swapping into memory locations. 2100 * The undefined behavior sanitizer gained two new options included in 2101 -fsanitize=undefined: -fsanitize=builtin which diagnoses at run 2102 time invalid arguments to __builtin_clz or __builtin_ctz prefixed 2103 builtins, and -fsanitize=pointer-overflow which performs cheap run 2104 time tests for pointer wrapping. 2105 * A new attribute no_sanitize can be applied to functions to instruct 2106 the compiler not to do sanitization of the options provided as 2107 arguments to the attribute. Acceptable values for no_sanitize match 2108 those acceptable by the -fsanitize command-line option. 2109 2110 void __attribute__ ((no_sanitize ("alignment", "object-size"))) 2111 f () { /* Do something. */; } 2112 2113 New Languages and Language specific improvements 2114 2115 Ada 2116 2117 * For its internal exception handling used on the host for error 2118 recovery in the front-end, the compiler now relies on the native 2119 exception handling mechanism of the host platform, which should be 2120 more efficient than the former mechanism. 2121 2122 BRIG (HSAIL) 2123 2124 In this release cycle, the focus for the BRIGFE was on stabilization 2125 and performance improvements. Also a couple of completely new features 2126 were added. 2127 * Improved support for function and module scope group segment 2128 variables. PRM specs define function and module scope group segment 2129 variables as an experimental feature. However, PRM test suite uses 2130 them. Now group segment is handled by separate book keeping of 2131 module scope and function (kernel) offsets. Each function has a 2132 "frame" in the group segment offset to which is given as an 2133 argument, similar to traditional call stack frame handling. 2134 * Reduce the number of type conversions due to the untyped HSAIL 2135 registers. Instead of always representing the HSAIL's untyped 2136 registers as unsigned int, the gccbrig now pre-analyzes the BRIG 2137 code and builds the register variables as a type used the most when 2138 storing or reading data to/from each register. This reduces the 2139 number of total casts which cannot be always optimized away. 2140 * Support for BRIG_KIND_NONE directives. 2141 * Made -O3 the default optimization level for BRIGFE. 2142 * Fixed illegal addresses generated from address expressions which 2143 refer only to offset 0. 2144 * Fixed a bug with reg+offset addressing on 32b segments. In 'large' 2145 mode, the offset is treated as 32bits unless it's in global, 2146 read-only or kernarg address space. 2147 * Fixed a crash caused sometimes by calls with more than 4 arguments. 2148 * Fixed a mis-execution issue with kernels that have both unexpanded 2149 ID functions and calls to subfunctions. 2150 * Treat HSAIL barrier builtins as setjmp/longjump style functions to 2151 avoid illegal optimizations. 2152 * Ensure per WI copies of private variables are aligned correctly. 2153 * libhsail-rt: Assume the host runtime allocates the work group 2154 memory. 2155 2156 C family 2157 2158 * New command-line options have been added for the C and C++ 2159 compilers: 2160 + [4]-Wmultistatement-macros warns about unsafe macros expanding 2161 to multiple statements used as a body of a statement such as 2162 if, else, while, switch, or for. 2163 + [5]-Wstringop-truncation warns for calls to bounded string 2164 manipulation functions such as strncat, strncpy, and stpncpy 2165 that might either truncate the copied string or leave the 2166 destination unchanged. For example, the following call to 2167 strncat is diagnosed because it appends just three of the four 2168 characters from the source string. 2169 void append (char *buf, size_t bufsize) 2170 { 2171 strncat (buf, ".txt", 3); 2172 } 2173 warning: 'strncat' output truncated copying 3 bytes from a string of length 4 [- 2174 Wstringop-truncation] 2175 Similarly, in the following example, the call to strncpy 2176 specifies the size of the destination buffer as the bound. If 2177 the length of the source string is equal to or greater than 2178 this size the result of the copy will not be NUL-terminated. 2179 Therefore, the call is also diagnosed. To avoid the warning, 2180 specify sizeof buf - 1 as the bound and set the last element 2181 of the buffer to NUL. 2182 void copy (const char *s) 2183 { 2184 char buf[80]; 2185 strncpy (buf, s, sizeof buf); 2186 ... 2187 } 2188 warning: 'strncpy' specified bound 80 equals destination size [-Wstringop-trunca 2189 tion] 2190 The -Wstringop-truncation option is included in -Wall. 2191 Note that due to GCC bug [6]82944, defining strncat, strncpy, 2192 or stpncpy as a macro in a system header as some 2193 implementations do, suppresses the warning. 2194 + [7]-Wif-not-aligned controls warnings issued in response to 2195 invalid uses of objects declared with attribute 2196 [8]warn_if_not_aligned. 2197 The -Wif-not-aligned option is included in -Wall. 2198 + [9]-Wmissing-attributes warns when a declaration of a function 2199 is missing one or more attributes that a related function is 2200 declared with and whose absence may adversely affect the 2201 correctness or efficiency of generated code. For example, in 2202 C++, the warning is issued when an explicit specialization of 2203 a primary template declared with attribute alloc_align, 2204 alloc_size, assume_aligned, format, format_arg, malloc, or 2205 nonnull is declared without it. Attributes deprecated, error, 2206 and warning suppress the warning. 2207 The -Wmissing-attributes option is included in -Wall. 2208 + [10]-Wpacked-not-aligned warns when a struct or union declared 2209 with attribute packed defines a member with an explicitly 2210 specified alignment greater than 1. Such a member will wind up 2211 under-aligned. For example, a warning will be issued for the 2212 definition of struct A in the following: 2213 struct __attribute__ ((aligned (8))) 2214 S8 { char a[8]; }; 2215 2216 struct __attribute__ ((packed)) A 2217 { 2218 struct S8 s8; 2219 }; 2220 warning: alignment 1 of 'struct S' is less than 8 [-Wpacked-not-aligned] 2221 The -Wpacked-not-aligned option is included in -Wall. 2222 + -Wcast-function-type warns when a function pointer is cast to 2223 an incompatible function pointer. This warning is enabled by 2224 -Wextra. 2225 + -Wsizeof-pointer-div warns for suspicious divisions of the 2226 size of a pointer by the size of the elements it points to, 2227 which looks like the usual way to compute the array size but 2228 won't work out correctly with pointers. This warning is 2229 enabled by -Wall. 2230 + -Wcast-align=strict warns whenever a pointer is cast such that 2231 the required alignment of the target is increased. For 2232 example, warn if a char * is cast to an int * regardless of 2233 the target machine. 2234 + -fprofile-abs-path creates absolute path names in the .gcno 2235 files. This allows gcov to find the correct sources in 2236 projects where compilations occur with different working 2237 directories. 2238 * -fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer and 2239 signed integer overflow is now undefined by default at all 2240 optimization levels. Using -fsanitize=signed-integer-overflow is 2241 now the preferred way to audit code, -Wstrict-overflow is 2242 deprecated. 2243 * The [11]-Warray-bounds option has been improved to detect more 2244 instances of out-of-bounds array indices and pointer offsets. For 2245 example, negative or excessive indices into flexible array members 2246 and string literals are detected. 2247 * The [12]-Wrestrict option introduced in GCC 7 has been enhanced to 2248 detect many more instances of overlapping accesses to objects via 2249 restrict-qualified arguments to standard memory and string 2250 manipulation functions such as memcpy and strcpy. For example, the 2251 strcpy call in the function below attempts to truncate the string 2252 by replacing its initial characters with the last four. However, 2253 because the function writes the terminating NUL into a[4], the 2254 copies overlap and the call is diagnosed. 2255 void f (void) 2256 { 2257 char a[] = "abcd1234"; 2258 strcpy (a, a + 4); 2259 ... 2260 } 2261 warning: 'strcpy' accessing 5 bytes at offsets 0 and 4 overlaps 1 byte at offset 2262 4 [-Wrestrict] 2263 The -Wrestrict option is included in -Wall. 2264 * Several optimizer enhancements have enabled improvements to the 2265 [13]-Wformat-overflow and [14]-Wformat-truncation options. The 2266 warnings detect more instances of buffer overflow and truncation 2267 than in GCC 7 and are better at avoiding certain kinds of false 2268 positives. 2269 * When reporting mismatching argument types at a function call, the C 2270 and C++ compilers now underline both the argument and the pertinent 2271 parameter in the declaration. 2272 $ gcc arg-type-mismatch.cc 2273 arg-type-mismatch.cc: In function 'int caller(int, int, float)': 2274 arg-type-mismatch.cc:5:24: error: invalid conversion from 'int' to 'const char*' 2275 [-fpermissive] 2276 return callee(first, second, third); 2277 ^~~~~~ 2278 arg-type-mismatch.cc:1:40: note: initializing argument 2 of 'int callee(int, c 2279 onst char*, float)' 2280 extern int callee(int one, const char *two, float three); 2281 ~~~~~~~~~~~~^~~ 2282 2283 * When reporting on unrecognized identifiers, the C and C++ compilers 2284 will now emit fix-it hints suggesting #include directives for 2285 various headers in the C and C++ standard libraries. 2286 $ gcc incomplete.c 2287 incomplete.c: In function 'test': 2288 incomplete.c:3:10: error: 'NULL' undeclared (first use in this function) 2289 return NULL; 2290 ^~~~ 2291 incomplete.c:3:10: note: 'NULL' is defined in header '<stddef.h>'; did you forge 2292 t to '#include <stddef.h>'? 2293 incomplete.c:1:1: 2294 +#include <stddef.h> 2295 const char *test(void) 2296 incomplete.c:3:10: 2297 return NULL; 2298 ^~~~ 2299 incomplete.c:3:10: note: each undeclared identifier is reported only once for ea 2300 ch function it appears in 2301 2302 $ gcc incomplete.cc 2303 incomplete.cc:1:6: error: 'string' in namespace 'std' does not name a type 2304 std::string s("hello world"); 2305 ^~~~~~ 2306 incomplete.cc:1:1: note: 'std::string' is defined in header '<string>'; did you 2307 forget to '#include <string>'? 2308 +#include <string> 2309 std::string s("hello world"); 2310 ^~~ 2311 2312 * The C and C++ compilers now use more intuitive locations when 2313 reporting on missing semicolons, and offer fix-it hints: 2314 $ gcc t.c 2315 t.c: In function 'test': 2316 t.c:3:12: error: expected ';' before '}' token 2317 return 42 2318 ^ 2319 ; 2320 } 2321 ~ 2322 2323 * When reporting on missing '}' and ')' tokens, the C and C++ 2324 compilers will now highlight the corresponding '{' and '(' token, 2325 issuing a 'note' if it's on a separate line: 2326 $ gcc unclosed.c 2327 unclosed.c: In function 'log_when_out_of_range': 2328 unclosed.c:12:50: error: expected ')' before '{' token 2329 && (temperature < MIN || temperature > MAX) { 2330 ^~ 2331 ) 2332 unclosed.c:11:6: note: to match this '(' 2333 if (logging_enabled && check_range () 2334 ^ 2335 2336 or highlighting it directly if it's on the same line: 2337 $ gcc unclosed-2.c 2338 unclosed-2.c: In function 'test': 2339 unclosed-2.c:8:45: error: expected ')' before '{' token 2340 if (temperature < MIN || temperature > MAX { 2341 ~ ^~ 2342 ) 2343 2344 They will also emit fix-it hints. 2345 2346 C++ 2347 2348 * GCC 8 (-fabi-version=12) has a couple of corrections to the calling 2349 convention, which changes the ABI for some uncommon code: 2350 + Passing an empty class as an argument now takes up no space on 2351 x86_64, as required by the psABI. 2352 + Passing or returning a class with only deleted copy and move 2353 constructors now uses the same calling convention as a class 2354 with a non-trivial copy or move constructor. This only affects 2355 C++17 mode, as in earlier standards passing or returning such 2356 a class was impossible. 2357 + WARNING: In GCC 8.1 the second change mistakenly also affects 2358 classes with a deleted copy constructor and defaulted trivial 2359 move constructor (bug [15]c++/86094). This issue is fixed in 2360 GCC 8.2 (-fabi-version=13). 2361 You can test whether these changes affect your code with -Wabi=11 2362 (or -Wabi=12 in GCC 8.2 for the third issue); if these changes are 2363 problematic for your project, the GCC 7 ABI can be selected with 2364 -fabi-version=11. 2365 * The value of the C++11 alignof operator has been corrected to match 2366 C _Alignof (minimum alignment) rather than GNU __alignof__ 2367 (preferred alignment); on ia32 targets this means that 2368 alignof(double) is now 4 rather than 8. Code that wants the 2369 preferred alignment should use __alignof__ instead. 2370 * New command-line options have been added for the C++ compiler to 2371 control warnings: 2372 + [16]-Wclass-memaccess warns when objects of non-trivial class 2373 types are manipulated in potentially unsafe ways by raw memory 2374 functions such as memcpy, or realloc. The warning helps detect 2375 calls that bypass user-defined constructors or copy-assignment 2376 operators, corrupt virtual table pointers, data members of 2377 const-qualified types or references, or member pointers. The 2378 warning also detects calls that would bypass access controls 2379 to data members. For example, a call such as: 2380 memcpy (&std::cout, &std::cerr, sizeof std::cout); 2381 results in 2382 warning: 'void* memcpy(void*, const void*, long unsigned int)' writing t 2383 o an object of type 'std::ostream' {aka 'class std::basic_ostream<char>'} with n 2384 o trivial copy-assignment [-Wclass-memaccess] 2385 The -Wclass-memaccess option is included in -Wall. 2386 * The C++ front end has experimental support for some of the upcoming 2387 C++2a draft features with the -std=c++2a or -std=gnu++2a flags, 2388 including designated initializers, default member initializers for 2389 bit-fields, __VA_OPT__ (except that #__VA_OPT__ is unsupported), 2390 lambda [=, this] captures, etc. For a full list of new features, 2391 see [17]the C++ status page. 2392 * When reporting on attempts to access private fields of a class or 2393 struct, the C++ compiler will now offer fix-it hints showing how to 2394 use an accessor function to get at the field in question, if one 2395 exists. 2396 $ gcc accessor.cc 2397 accessor.cc: In function 'void test(foo*)': 2398 accessor.cc:12:12: error: 'double foo::m_ratio' is private within this context 2399 if (ptr->m_ratio >= 0.5) 2400 ^~~~~~~ 2401 accessor.cc:7:10: note: declared private here 2402 double m_ratio; 2403 ^~~~~~~ 2404 accessor.cc:12:12: note: field 'double foo::m_ratio' can be accessed via 'double 2405 foo::get_ratio() const' 2406 if (ptr->m_ratio >= 0.5) 2407 ^~~~~~~ 2408 get_ratio() 2409 2410 * The C++ compiler can now give you a hint if you use a macro before 2411 it was defined (e.g. if you mess up the order of your #include 2412 directives): 2413 $ gcc ordering.cc 2414 ordering.cc:2:24: error: expected ';' at end of member declaration 2415 virtual void clone() const OVERRIDE { } 2416 ^~~~~ 2417 ; 2418 ordering.cc:2:30: error: 'OVERRIDE' does not name a type 2419 virtual void clone() const OVERRIDE { } 2420 ^~~~~~~~ 2421 ordering.cc:2:30: note: the macro 'OVERRIDE' had not yet been defined 2422 In file included from ordering.cc:5: 2423 c++11-compat.h:2: note: it was later defined here 2424 #define OVERRIDE override 2425 2426 2427 * The -Wold-style-cast diagnostic can now emit fix-it hints telling 2428 you when you can use a static_cast, const_cast, or 2429 reinterpret_cast. 2430 $ gcc -c old-style-cast-fixits.cc -Wold-style-cast 2431 old-style-cast-fixits.cc: In function 'void test(void*)': 2432 old-style-cast-fixits.cc:5:19: warning: use of old-style cast to 'struct foo*' [ 2433 -Wold-style-cast] 2434 foo *f = (foo *)ptr; 2435 ^~~ 2436 ---------- 2437 static_cast<foo *> (ptr) 2438 2439 * When reporting on problems within extern "C" linkage 2440 specifications, the C++ compiler will now display the location of 2441 the start of the extern "C". 2442 $ gcc -c extern-c.cc 2443 extern-c.cc:3:1: error: template with C linkage 2444 template <typename T> void test (void); 2445 ^~~~~~~~ 2446 In file included from extern-c.cc:1: 2447 unclosed.h:1:1: note: 'extern "C"' linkage started here 2448 extern "C" { 2449 ^~~~~~~~~~ 2450 extern-c.cc:3:39: error: expected '}' at end of input 2451 template <typename T> void test (void); 2452 ^ 2453 In file included from extern-c.cc:1: 2454 unclosed.h:1:12: note: to match this '{' 2455 extern "C" { 2456 ^ 2457 2458 * When reporting on mismatching template types, the C++ compiler will 2459 now use color to highlight the mismatching parts of the template, 2460 and will elide the parameters that are common between two 2461 mismatching templates, printing [...] instead: 2462 $ gcc templates.cc 2463 templates.cc: In function 'void test()': 2464 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 2465 e>' to 'vector<int>' 2466 fn_1(vector<double> ()); 2467 ^~~~~~~~~~~~~~~~~ 2468 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<[...] 2469 ,double>' to 'map<[...],int>' 2470 fn_2(map<int, double>()); 2471 ^~~~~~~~~~~~~~~~~~ 2472 2473 Those [...] elided parameters can be seen using -fno-elide-type: 2474 $ gcc templates.cc -fno-elide-type 2475 templates.cc: In function 'void test()': 2476 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl 2477 e>' to 'vector<int>' 2478 fn_1(vector<double> ()); 2479 ^~~~~~~~~~~~~~~~~ 2480 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<int,d 2481 ouble>' to 'map<int,int>' 2482 fn_2(map<int, double>()); 2483 ^~~~~~~~~~~~~~~~~~ 2484 2485 The C++ compiler has also gained an option 2486 -fdiagnostics-show-template-tree which visualizes such mismatching 2487 templates in a hierarchical form: 2488 $ gcc templates-2.cc -fdiagnostics-show-template-tree 2489 templates-2.cc: In function 'void test()': 2490 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 2491 ble>' to 'vector<int>' 2492 vector< 2493 [double != int]> 2494 fn_1(vector<double> ()); 2495 ^~~~~~~~~~~~~~~~~ 2496 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 2497 ctor<double> >()' from 'map<map<[...],vector<double>>,vector<double>>' to 'map<m 2498 ap<[...],vector<float>>,vector<float>>' 2499 map< 2500 map< 2501 [...], 2502 vector< 2503 [double != float]>>, 2504 vector< 2505 [double != float]>> 2506 fn_2(map<map<int, vector<double>>, vector<double>> ()); 2507 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2508 2509 which again works with -fno-elide-type: 2510 $ gcc templates-2.cc -fdiagnostics-show-template-tree -fno-elide-type 2511 templates-2.cc: In function 'void test()': 2512 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou 2513 ble>' to 'vector<int>' 2514 vector< 2515 [double != int]> 2516 fn_1(vector<double> ()); 2517 ^~~~~~~~~~~~~~~~~ 2518 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve 2519 ctor<double> >()' from 'map<map<int,vector<double>>,vector<double>>' to 'map<map 2520 <int,vector<float>>,vector<float>>' 2521 map< 2522 map< 2523 int, 2524 vector< 2525 [double != float]>>, 2526 vector< 2527 [double != float]>> 2528 fn_2(map<map<int, vector<double>>, vector<double>> ()); 2529 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2530 2531 * Flowing off the end of a non-void function is considered 2532 unreachable and may be subject to optimization on that basis. As a 2533 result of this change, -Wreturn-type warnings are enabled by 2534 default for C++. 2535 2536 Runtime Library (libstdc++) 2537 2538 * Improved experimental support for C++17, including the following 2539 features: 2540 + Deduction guides to support class template argument deduction. 2541 + std::filesystem implementation. 2542 + std::char_traits<char> and std::char_traits<wchar_t> are 2543 usable in constant expressions. 2544 + std::to_chars and std::from_chars (for integers only, not for 2545 floating point types). 2546 * Experimental support for C++2a: std::to_address (thanks to Glen 2547 Fernandes) and std::endian. 2548 * On GNU/Linux, std::random_device::entropy() accesses the kernel's 2549 entropy count for the random device, if known (thanks to Xi 2550 Ruoyao). 2551 * Support for std::experimental::source_location. 2552 * AddressSanitizer integration for std::vector, detecting 2553 out-of-range accesses to the unused capacity of a vector. 2554 * Extensions __gnu_cxx::airy_ai and __gnu_cxx::airy_bi added to the 2555 Mathematical Special Functions. 2556 2557 Fortran 2558 2559 * The main version of libfortran has been changed to 5. 2560 * Parameterized derived types, a major feature of Fortran 2003, have 2561 been implemented. 2562 * Partial support is provided for Fortran 2018 teams, which are 2563 hierarchical subsets of images that execute independently of other 2564 image subsets. 2565 * The maximum rank for arrays has been increased to 15, conforming to 2566 the Fortran 2008 standard. 2567 * Transformational intrinsics are now fully supported in 2568 initialization expressions. 2569 * New flag -fc-prototypes to write C prototypes for BIND(C) 2570 procedures and variables. 2571 * If -fmax-stack-var-size is honored if given together with -Ofast, 2572 -fstack-arrays is no longer set in that case. 2573 * New options -fdefault-real-16 and -fdefault-real-10 to control the 2574 default kind of REAL variables. 2575 * A warning is now issued if an array subscript inside a DO loop 2576 could lead to an out-of-bounds-access. The new option 2577 -Wdo-subscript, enabled by -Wextra, warns about this even if the 2578 compiler can not prove that the code will be executed. 2579 * The Fortran front end now attempts to interchange loops if it is 2580 deemed profitable. So far, this is restricted to FORALL and DO 2581 CONCURRENT statements with multiple indices. This behavior be 2582 controlled with the new flag -ffrontend-loop-interchange, which is 2583 enabled with optimization by default. The 2584 -Wfrontend-loop-interchange option warns about such occurrences. 2585 * When an actual argument contains too few elements for a dummy 2586 argument, an error is now issued. The -std=legacy option can be 2587 used to still compile such code. 2588 * The RECL= argument to OPEN and INQUIRE statements now allows 64-bit 2589 integers, making records larger than 2GiB possible. 2590 * The GFORTRAN_DEFAULT_RECL environment variable no longer has any 2591 effect. The record length for preconnected units is now larger than 2592 any practical limit, same as for sequential access units opened 2593 without an explicit RECL= specifier. 2594 * Character variables longer than HUGE(0) elements are now possible 2595 on 64-bit targets. Note that this changes the procedure call ABI 2596 for all procedures with character arguments on 64-bit targets, as 2597 the type of the hidden character length argument has changed. The 2598 hidden character length argument is now of type INTEGER(C_SIZE_T). 2599 * Partial support is provided for Fortran 2018 teams, which are 2600 hierarchical subsets of images that execute independently of other 2601 image subsets. 2602 2603 Go 2604 2605 * GCC 8 provides a complete implementation of the Go 1.10.1 user 2606 packages. 2607 * The garbage collector is now fully concurrent. As before, values 2608 stored on the stack are scanned conservatively, but value stored in 2609 the heap are scanned precisely. 2610 * Escape analysis is fully implemented and enabled by default in the 2611 Go front end. This significantly reduces the number of heap 2612 allocations by allocating values on the stack instead. 2613 2614 libgccjit 2615 2616 The libgccjit API gained four new entry points: 2617 * [18]gcc_jit_type_get_vector and 2618 * [19]gcc_jit_context_new_rvalue_from_vector for working with 2619 vectors, 2620 * [20]gcc_jit_type_get_aligned 2621 * [21]gcc_jit_function_get_address 2622 2623 The C code generated by [22]gcc_jit_context_dump_reproducer_to_file is 2624 now easier-to-read. 2625 2626 New Targets and Target Specific Improvements 2627 2628 AArch64 2629 2630 * The Armv8.4-A architecture is now supported. It can be used by 2631 specifying the -march=armv8.4-a option. 2632 * The Dot Product instructions are now supported as an optional 2633 extension to the Armv8.2-A architecture and newer and are mandatory 2634 on Armv8.4-A. The extension can be used by specifying the +dotprod 2635 architecture extension. E.g. -march=armv8.2-a+dotprod. 2636 * The Armv8-A +crypto extension has now been split into two 2637 extensions for finer grained control: 2638 + +aes which contains the Armv8-A AES crytographic instructions. 2639 + +sha2 which contains the Armv8-A SHA2 and SHA1 cryptographic 2640 instructions. 2641 Using +crypto will now enable these two extensions. 2642 * New Armv8.4-A FP16 Floating Point Multiplication Variant 2643 instructions have been added. These instructions are mandatory in 2644 Armv8.4-A but available as an optional extension to Armv8.2-A and 2645 Armv8.3-A. The new extension can be used by specifying the +fp16fml 2646 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 2647 the instructions can be enabled by specifying +fp16. 2648 * New cryptographic instructions have been added as optional 2649 extensions to Armv8.2-A and newer. These instructions can be 2650 enabled with: 2651 + +sha3 New SHA3 and SHA2 instructions from Armv8.4-A. This 2652 implies +sha2. 2653 + +sm4 New SM3 and SM4 instructions from Armv8.4-A. 2654 * The Scalable Vector Extension (SVE) is now supported as an optional 2655 extension to the Armv8.2-A architecture and newer. This support 2656 includes automatic vectorization with SVE instructions, but it does 2657 not yet include the SVE Arm C Language Extensions (ACLE). It can be 2658 enabled by specifying the +sve architecture extension (for example, 2659 -march=armv8.2-a+sve). By default, the generated code works with 2660 all vector lengths, but it can be made specific to N-bit vectors 2661 using -msve-vector-bits=N. 2662 * Support has been added for the following processors (GCC 2663 identifiers in parentheses): 2664 + Arm Cortex-A75 (cortex-a75). 2665 + Arm Cortex-A55 (cortex-a55). 2666 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 2667 (cortex-a75.cortex-a55). 2668 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2669 options, for example: -mcpu=cortex-a75 or -mtune=cortex-a75 or as 2670 arguments to the equivalent target attributes and pragmas. 2671 2672 ARC 2673 2674 * Added support for: 2675 + Fast interrupts. 2676 + Naked functions. 2677 + aux variable attributes. 2678 + uncached type qualifier. 2679 + Secure functions via sjli instruction. 2680 * New exception handling implementation. 2681 * Revamped trampoline implementation. 2682 * Refactored small data feature implementation, controlled via -G 2683 command line option. 2684 * New support for reduced register set ARC architecture 2685 configurations, controlled via -mrf16 command line option. 2686 * Refurbished and improved support for zero overhead loops. 2687 Introduced -mlpc-width command line option to control the width of 2688 lp_count register. 2689 2690 ARM 2691 2692 * The -mfpu option now takes a new option setting of -mfpu=auto. When 2693 set to this the floating-point and SIMD settings are derived from 2694 the settings of the -mcpu or -march options. The internal CPU 2695 configurations have been updated with information about the 2696 permitted floating-point configurations supported. See the user 2697 guide for further information about the extended option syntax for 2698 controlling architectural extensions via the -march option. 2699 -mfpu=auto is now the default setting unless the compiler has been 2700 configured with an explicit --with-fpu option. 2701 * The -march and -mcpu options now accept optional extensions to the 2702 architecture or CPU option, allowing the user to enable or disable 2703 any such extensions supported by that architecture or CPU such as 2704 (but not limited to) floating-point and AdvancedSIMD. For example: 2705 the option -mcpu=cortex-a53+nofp will generate code for the 2706 Cortex-A53 processor with no floating-point support. This, in 2707 combination with the new -mfpu=auto option, provides a 2708 straightforward way of specifying a valid build target through a 2709 single -mcpu or -march option. The -mtune option accepts the same 2710 arguments as -mcpu but only the CPU name has an effect on tuning. 2711 The architecture extensions do not have any effect. For details of 2712 what extensions a particular architecture or CPU option supports 2713 please refer to the [23]documentation. 2714 * The -mstructure-size-boundary option has been deprecated and will 2715 be removed in a future release. 2716 * The default link behavior for Armv6 and Armv7-R targets has been 2717 changed to produce BE8 format when generating big-endian images. A 2718 new flag -mbe32 can be used to force the linker to produce legacy 2719 BE32 format images. There is no change of behavior for Armv6-M and 2720 other Armv7 or later targets: these already defaulted to BE8 2721 format. This change brings GCC into alignment with other compilers 2722 for the ARM architecture. 2723 * The Armv8-R architecture is now supported. It can be used by 2724 specifying the -march=armv8-r option. 2725 * The Armv8.3-A architecture is now supported. It can be used by 2726 specifying the -march=armv8.3-a option. 2727 * The Armv8.4-A architecture is now supported. It can be used by 2728 specifying the -march=armv8.4-a option. 2729 * The Dot Product instructions are now supported as an optional 2730 extension to the Armv8.2-A architecture and newer and are mandatory 2731 on Armv8.4-A. The extension can be used by specifying the +dotprod 2732 architecture extension. E.g. -march=armv8.2-a+dotprod. 2733 * Support for setting extensions and architectures using the GCC 2734 target pragma and attribute has been added. It can be used by 2735 specifying #pragma GCC target ("arch=..."), #pragma GCC target 2736 ("+extension"), __attribute__((target("arch=..."))) or 2737 __attribute__((target("+extension"))). 2738 * New Armv8.4-A FP16 Floating Point Multiplication Variant 2739 instructions have been added. These instructions are mandatory in 2740 Armv8.4-A but available as an optional extension to Armv8.2-A and 2741 Armv8.3-A. The new extension can be used by specifying the +fp16fml 2742 architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A 2743 the instructions can be enabled by specifying +fp16. 2744 * Support has been added for the following processors (GCC 2745 identifiers in parentheses): 2746 + Arm Cortex-A75 (cortex-a75). 2747 + Arm Cortex-A55 (cortex-a55). 2748 + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE 2749 (cortex-a75.cortex-a55). 2750 + Arm Cortex-R52 for Armv8-R (cortex-r52). 2751 The GCC identifiers can be used as arguments to the -mcpu or -mtune 2752 options, for example: -mcpu=cortex-a75 or -mtune=cortex-r52 or as 2753 arguments to the equivalent target attributes and pragmas. 2754 2755 AVR 2756 2757 * The AVR port now supports the following XMEGA-like devices: 2758 2759 ATtiny212, ATtiny214, ATtiny412, ATtiny414, ATtiny416, ATtiny417, 2760 ATtiny814, ATtiny816, ATtiny817, ATtiny1614, ATtiny1616, ATtiny1617, 2761 ATtiny3214, ATtiny3216, ATtiny3217 2762 The new devices are listed under [24]-mmcu=avrxmega3. 2763 + These devices see flash memory in the RAM address space, so 2764 that features like PROGMEM and __flash are not needed any more 2765 (as opposed to other AVR families for which read-only data 2766 will be located in RAM except special, non-standard features 2767 are used to locate and access such data). This requires that 2768 the compiler is used with Binutils 2.29 or newer so that 2769 [25]read-only data will be located in flash memory. 2770 + A new command-line option -mshort-calls is supported. This 2771 option is used internally for multilib selection of the 2772 avrxmega3 variants. It is not an optimization option. Do not 2773 set it by hand. 2774 * The compiler now generates [26]efficient interrupt service routine 2775 (ISR) prologues and epilogues. This is achieved by using the new 2776 [27]AVR pseudo instruction __gcc_isr which is supported and 2777 resolved by the GNU assembler. 2778 + As the __gcc_isr pseudo-instruction will be resolved by the 2779 assembler, inline assembly is transparent to the process. This 2780 means that when inline assembly uses an instruction like INC 2781 that clobbers the condition code, then the assembler will 2782 detect this and generate an appropriate ISR prologue / 2783 epilogue chunk to save / restore SREG as needed. 2784 + A new command-line option -mno-gas-isr-prologues disables the 2785 generation of the __gcc_isr pseudo instruction. Any non-naked 2786 ISR will save and restore SREG, tmp_reg and zero_reg, no 2787 matter whether the respective register is clobbered or used. 2788 + The feature is turned on per default for all optimization 2789 levels except for -O0 and -Og. It is explicitly enabled by 2790 means of option -mgas-isr-prologues. 2791 + Support has been added for a new [28]AVR function attribute 2792 no_gccisr. It can be used to disable __gcc_isr pseudo 2793 instruction generation for individual ISRs. 2794 + This optimization is only available if GCC is configured with 2795 GNU Binutils 2.29 or newer; or at least with a version of 2796 Binutils that implements feature [29]PR21683. 2797 * The compiler no more saves / restores registers in main; the effect 2798 is the same as if attribute OS_task was specified for main. This 2799 optimization can be switched off by the new command-line option 2800 -mno-main-is-OS_task. 2801 2802 IA-32/x86-64 2803 2804 * The x86 port now supports the naked function attribute. 2805 * Better tuning for znver1 and Intel Core based CPUs. 2806 * Vectorization cost metrics has been reworked leading to significant 2807 improvements on some benchmarks. 2808 * GCC now supports the Intel CPU named Cannonlake through 2809 -march=cannonlake. The switch enables the AVX512VBMI, AVX512IFMA 2810 and SHA ISA extensions. 2811 * GCC now supports the Intel CPU named Icelake through 2812 -march=icelake. The switch enables the AVX512VNNI, GFNI, VAES, 2813 AVX512VBMI2, VPCLMULQDQ, AVX512BITALG, RDPID and AVX512VPOPCNTDQ 2814 ISA extensions. 2815 * GCC now supports the Intel Control-flow Enforcement Technology 2816 (CET) extension through -fcf-protection option. 2817 2818 NDS32 2819 2820 * New command-line options -mext-perf, -mext-perf2, and -mext-string 2821 have been added for performance extension instructions. 2822 2823 Nios II 2824 2825 * The Nios II back end has been improved to generate better-optimized 2826 code. Changes include switching to LRA, more accurate cost models, 2827 and more compact code for addressing static variables. 2828 * New command-line options -mgprel-sec= and -mr0rel-sec= have been 2829 added. 2830 * The stack-smashing protection options are now enabled on Nios II. 2831 2832 PA-RISC 2833 2834 * The default call ABI on 32-bit linux has been changed from callee 2835 copies to caller copies. This affects objects larger than eight 2836 bytes passed by value. The goal is to improve compatibility with 2837 x86 and resolve issues with OpenMP. 2838 * Other PA-RISC targets are unchanged. 2839 2840 PowerPC / PowerPC64 / RS6000 2841 2842 * The PowerPC SPE support is split off to a separate powerpcspe port. 2843 The separate port is deprecated and might be removed in a future 2844 release. 2845 * The Paired Single support (as used on some PPC750 CPUs, -mpaired, 2846 powerpc*-*-linux*paired*) is deprecated and will be removed in a 2847 future release. 2848 * The Xilinx floating point support (-mxilinx-fpu, 2849 powerpc-xilinx-eabi*) is deprecated and will be removed in a future 2850 release. 2851 * Support for using big-endian AltiVec intrinsics on a little-endian 2852 target (-maltivec=be) is deprecated and will be removed in a future 2853 release. 2854 2855 Tile 2856 2857 * The TILE-Gx port is deprecated and will be removed in a future 2858 release. 2859 2860 Operating Systems 2861 2862 Windows 2863 2864 * GCC on Microsoft Windows can now be configured via 2865 --enable-mingw-wildcard or --disable-mingw-wildcard to force a 2866 specific behavior for GCC itself with regards to supporting the 2867 wildcard character. Prior versions of GCC would follow the 2868 configuration of the MinGW runtime. This behavior can still be 2869 obtained by not using the above options or by using 2870 --enable-mingw-wildcard=platform. 2871 2872 Improvements for plugin authors 2873 2874 * Plugins can now register a callback hook for when comments are 2875 encountered by the C and C++ compilers, e.g. allowing for plugins 2876 to handle documentation markup in code comments. 2877 * The gdbinit support script for debugging GCC now has a 2878 break-on-diagnostic command, providing an easy way to trigger a 2879 breakpoint whenever a diagnostic is emitted. 2880 * The API for creating fix-it hints now supports newlines, and for 2881 emitting mutually incompatible fix-it hints for one diagnostic. 2882 2883 GCC 8.1 2884 2885 This is the [30]list of problem reports (PRs) from GCC's bug tracking 2886 system that are known to be fixed in the 8.1 release. This list might 2887 not be complete (that is, it is possible that some PRs that have been 2888 fixed are not listed here). 2889 2890 GCC 8.2 2891 2892 This is the [31]list of problem reports (PRs) from GCC's bug tracking 2893 system that are known to be fixed in the 8.2 release. This list might 2894 not be complete (that is, it is possible that some PRs that have been 2895 fixed are not listed here). 2896 2897 General Improvements 2898 2899 * Fixed LTO link-time performance problems caused by an overflow in 2900 the partitioning algorithm while building large binaries. 2901 2902 Language Specific Changes 2903 2904 C++ 2905 2906 GCC 8.2 fixed a bug introduced in GCC 8.1 affecting passing or 2907 returning of classes with a deleted copy constructor and defaulted 2908 trivial move constructor (bug [32]c++/86094). GCC 8.2 introduces 2909 -fabi-version=13 and makes it the default, ABI incompatibilities 2910 between GCC 8.1 and 8.2 can be reported with -Wabi=12. See [33]C++ 2911 changes for more details. 2912 2913 Target Specific Changes 2914 2915 IA-32/x86-64 2916 2917 * -mtune=native performance regression [34]PR84413 on Intel Skylake 2918 processors has been fixed. 2919 2920 GCC 8.3 2921 2922 This is the [35]list of problem reports (PRs) from GCC's bug tracking 2923 system that are known to be fixed in the 8.3 release. This list might 2924 not be complete (that is, it is possible that some PRs that have been 2925 fixed are not listed here). 2926 2927 Windows 2928 2929 * A C++ Microsoft ABI bitfield layout bug, [36]PR87137 has been 2930 fixed. A non-field declaration could cause the current bitfield 2931 allocation unit to be completed, incorrectly placing a following 2932 bitfield into a new allocation unit. The Microsoft ABI is selected 2933 for: 2934 + Mingw targets 2935 + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields 2936 option is specified, or __attribute__((ms_struct)) is used 2937 + SuperH targets when the -mhitachi option is specified, or 2938 __attribute__((renesas)) is used 2939 GCC 8 introduced additional cases of this defect, but rather than 2940 resolve only those regressions, we decided to resolve all the cases 2941 of this defect in single change. 2942 2943 GCC 8.4 2944 2945 This is the [37]list of problem reports (PRs) from GCC's bug tracking 2946 system that are known to be fixed in the 8.4 release. This list might 2947 not be complete (that is, it is possible that some PRs that have been 2948 fixed are not listed here). 2949 2950 GCC 8.5 2951 2952 Target Specific Changes 2953 2954 AArch64 2955 2956 * The option -moutline-atomics has been added to aid deployment of 2957 the Large System Extensions (LSE) on GNU/Linux systems built with a 2958 baseline architecture targeting Armv8-A. When the option is 2959 specified code is emitted to detect the presence of LSE 2960 instructions at run time and use them for standard atomic 2961 operations. For more information please refer to the documentation. 2962 2963 2964 For questions related to the use of GCC, please consult these web 2965 pages and the [38]GCC manuals. If that fails, the 2966 [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 2967 web pages and the development of GCC are welcome on our developer 2968 list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public 2969 archives. 2970 2971 Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and 2972 distribution of this entire article is permitted in any medium, 2973 provided this notice is preserved. 2974 2975 These pages are [43]maintained by the GCC team. Last modified 2976 2021-03-28[44]. 2977 2978 References 2979 2980 1. http://gcc.gnu.org/gcc-8/porting_to.html 2981 2. http://gcc.gnu.org/onlinedocs/index.html#current 2982 3. https://gcc.gnu.org/ml/gcc/2018-04/msg00102.html 2983 4. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmultistatement-macros 2984 5. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wstringop-truncation 2985 6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944 2986 7. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wif-not-aligned 2987 8. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Common-Variable-Attributes.html#index-warn_005fif_005fnot_005faligned-variable-attribute 2988 9. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmissing-attributes 2989 10. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wpacked-not-aligned 2990 11. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Warray-bounds 2991 12. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wrestrict 2992 13. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-overflow 2993 14. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-truncation 2994 15. https://gcc.gnu.org/PR86094 2995 16. https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wclass-memaccess 2996 17. http://gcc.gnu.org/projects/cxx-status.html#cxx2a 2997 18. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_vector 2998 19. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/expressions.html#gcc_jit_context_new_rvalue_from_vector 2999 20. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_aligned 3000 21. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/function-pointers.html#gcc_jit_function_get_address 3001 22. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/contexts.html#gcc_jit_context_dump_reproducer_to_file 3002 23. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/ARM-Options.html#ARM-Options 3003 24. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Options.html 3004 25. https://sourceware.org/PR21472 3005 26. https://gcc.gnu.org/PR20296 3006 27. https://sourceware.org/binutils/docs-2.29/as/AVR-Pseudo-Instructions.html 3007 28. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Function-Attributes.html 3008 29. https://sourceware.org/PR21683 3009 30. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.0 3010 31. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.2 3011 32. https://gcc.gnu.org/PR86094 3012 33. http://gcc.gnu.org/gcc-8/changes.html#cxx 3013 34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84413 3014 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.3 3015 36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137 3016 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.4 3017 38. https://gcc.gnu.org/onlinedocs/ 3018 39. mailto:gcc-help (a] gcc.gnu.org 3019 40. mailto:gcc (a] gcc.gnu.org 3020 41. https://gcc.gnu.org/lists.html 3021 42. https://www.fsf.org/ 3022 43. https://gcc.gnu.org/about.html 3023 44. http://validator.w3.org/check/referer 3024 ====================================================================== 3025 http://gcc.gnu.org/gcc-7/index.html 3026 3027 GCC 7 Release Series 3028 3029 Nov 14, 2019 3030 3031 The [1]GNU project and the GCC developers are pleased to announce the 3032 release of GCC 7.5. 3033 3034 This release is a bug-fix release, containing fixes for regressions in 3035 GCC 7.4 relative to previous releases of GCC. 3036 3037 Release History 3038 3039 GCC 7.5 3040 Nov 14, 2019 ([2]changes, [3]documentation) 3041 3042 GCC 7.4 3043 Dec 6, 2018 ([4]changes, [5]documentation) 3044 3045 GCC 7.3 3046 Jan 25, 2018 ([6]changes, [7]documentation) 3047 3048 GCC 7.2 3049 Aug 14, 2017 ([8]changes, [9]documentation) 3050 3051 GCC 7.1 3052 May 2, 2017 ([10]changes, [11]documentation) 3053 3054 References and Acknowledgements 3055 3056 GCC used to stand for the GNU C Compiler, but since the compiler 3057 supports several other languages aside from C, it now stands for the 3058 GNU Compiler Collection. 3059 3060 A list of [12]successful builds is updated as new information becomes 3061 available. 3062 3063 The GCC developers would like to thank the numerous people that have 3064 contributed new features, improvements, bug fixes, and other changes as 3065 well as test results to GCC. This [13]amazing group of volunteers is 3066 what makes GCC successful. 3067 3068 For additional information about GCC please refer to the [14]GCC 3069 project web site or contact the [15]GCC development mailing list. 3070 3071 To obtain GCC please use [16]our mirror sites or [17]our version 3072 control system. 3073 3074 3075 For questions related to the use of GCC, please consult these web 3076 pages and the [18]GCC manuals. If that fails, the 3077 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 3078 web pages and the development of GCC are welcome on our developer 3079 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 3080 archives. 3081 3082 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 3083 distribution of this entire article is permitted in any medium, 3084 provided this notice is preserved. 3085 3086 These pages are [23]maintained by the GCC team. Last modified 3087 2020-01-14[24]. 3088 3089 References 3090 3091 1. http://www.gnu.org/ 3092 2. http://gcc.gnu.org/gcc-7/changes.html 3093 3. http://gcc.gnu.org/onlinedocs/7.5.0/ 3094 4. http://gcc.gnu.org/gcc-7/changes.html 3095 5. http://gcc.gnu.org/onlinedocs/7.4.0/ 3096 6. http://gcc.gnu.org/gcc-7/changes.html 3097 7. http://gcc.gnu.org/onlinedocs/7.3.0/ 3098 8. http://gcc.gnu.org/gcc-7/changes.html 3099 9. http://gcc.gnu.org/onlinedocs/7.2.0/ 3100 10. http://gcc.gnu.org/gcc-7/changes.html 3101 11. http://gcc.gnu.org/onlinedocs/7.1.0/ 3102 12. http://gcc.gnu.org/gcc-7/buildstat.html 3103 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 3104 14. http://gcc.gnu.org/index.html 3105 15. mailto:gcc (a] gcc.gnu.org 3106 16. http://gcc.gnu.org/mirrors.html 3107 17. http://gcc.gnu.org/git.html 3108 18. https://gcc.gnu.org/onlinedocs/ 3109 19. mailto:gcc-help (a] gcc.gnu.org 3110 20. mailto:gcc (a] gcc.gnu.org 3111 21. https://gcc.gnu.org/lists.html 3112 22. https://www.fsf.org/ 3113 23. https://gcc.gnu.org/about.html 3114 24. http://validator.w3.org/check/referer 3115 ====================================================================== 3116 http://gcc.gnu.org/gcc-7/changes.html 3117 3118 GCC 7 Release Series 3119 Changes, New Features, and Fixes 3120 3121 This page is a brief summary of some of the huge number of improvements 3122 in GCC 7. For more information, see the [1]Porting to GCC 7 page and 3123 the [2]full GCC documentation. 3124 3125 Caveats 3126 3127 * GCC now uses [3]LRA (a new local register allocator) by default for 3128 new targets. 3129 * The non-standard C++0x type traits has_trivial_default_constructor, 3130 has_trivial_copy_constructor and has_trivial_copy_assign have been 3131 removed. 3132 * The libstdc++ [4]Profile Mode has been deprecated and will be 3133 removed in a future version. 3134 * The Cilk+ extensions to the C and C++ languages have been 3135 deprecated. 3136 * On ARM targets (arm*-*-*), [5]a bug introduced in GCC 5 that 3137 affects conformance to the procedure call standard (AAPCS) has been 3138 fixed. The bug affects some C++ code where class objects are passed 3139 by value to functions and could result in incorrect or inconsistent 3140 code being generated. This is an ABI change. If the option -Wpsabi 3141 is enabled (on by default) the compiler will emit a diagnostic note 3142 for code that might be affected. 3143 3144 General Optimizer Improvements 3145 3146 * GCC 7 can determine the return value or range of return values of 3147 some calls to the sprintf family of functions and make it available 3148 to other optimization passes. Some calls to the snprintf function 3149 with a zero size argument can be folded into constants. This 3150 optimization is included in -O1 and can be selectively controlled 3151 by the -fprintf-return-value option. 3152 * A new store merging pass has been added. It merges constant stores 3153 to adjacent memory locations into fewer, wider, stores. It is 3154 enabled by the -fstore-merging option and at the -O2 optimization 3155 level or higher (and -Os). 3156 * A new code hoisting optimization has been added to the partial 3157 redundancy elimination pass. It attempts to move evaluation of 3158 expressions executed on all paths to the function exit as early as 3159 possible. This primarily helps improve code size, but can improve 3160 the speed of the generated code as well. It is enabled by the 3161 -fcode-hoisting option and at the -O2 optimization level or higher 3162 (and -Os). 3163 * A new interprocedural bitwise constant propagation optimization has 3164 been added, which propagates knowledge about which bits of 3165 variables are known to be zero (including pointer alignment 3166 information) across the call graph. It is enabled by the 3167 -fipa-bit-cp option if -fipa-cp is enabled as well, and is enabled 3168 at the -O2 optimization level and higher (and -Os). This 3169 optimization supersedes interprocedural alignment propagation of 3170 GCC 6, and therefore the option -fipa-cp-alignment is now 3171 deprecated and ignored. 3172 * A new interprocedural value range propagation optimization has been 3173 added, which propagates integral range information across the call 3174 graph when variable values can be proven to be within those ranges. 3175 It is enabled by the -fipa-vrp option and at the -O2 optimization 3176 level and higher (and -Os). 3177 * A new loop splitting optimization pass has been added. Certain 3178 loops which contain a condition that is always true on one side of 3179 the iteration space and always false on the other are split into 3180 two loops, such that each of the two new loops iterates on just one 3181 side of the iteration space and the condition does not need to be 3182 checked inside of the loop. It is enabled by the -fsplit-loops 3183 option and at the -O3 optimization level or higher. 3184 * The shrink-wrapping optimization can now separate portions of 3185 prologues and epilogues to improve performance if some of the work 3186 done traditionally by prologues and epilogues is not needed on 3187 certain paths. This is controlled by the -fshrink-wrap-separate 3188 option, enabled by default. It requires target support, which is 3189 currently only implemented in the PowerPC and AArch64 ports. 3190 * AddressSanitizer gained a new sanitization option, 3191 -fsanitize-address-use-after-scope, which enables sanitization of 3192 variables whose address is taken and used after a scope where the 3193 variable is defined: 3194 3195 int 3196 main (int argc, char **argv) 3197 { 3198 char *ptr; 3199 { 3200 char my_char; 3201 ptr = &my_char; 3202 } 3203 3204 *ptr = 123; 3205 return *ptr; 3206 } 3207 3208 ==28882==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffb8dba99 3209 0 at pc 0x0000004006d5 bp 0x7fffb8dba960 sp 0x7fffb8dba958 3210 WRITE of size 1 at 0x7fffb8dba990 thread T0 3211 #0 0x4006d4 in main /tmp/use-after-scope-1.c:10 3212 #1 0x7f9c71943290 in __libc_start_main (/lib64/libc.so.6+0x20290) 3213 #2 0x400739 in _start (/tmp/a.out+0x400739) 3214 3215 Address 0x7fffb8dba990 is located in stack of thread T0 at offset 32 in frame 3216 #0 0x40067f in main /tmp/use-after-scope-1.c:3 3217 3218 This frame has 1 object(s): 3219 [32, 33) 'my_char' <== Memory access at offset 32 is inside this variable 3220 3221 The option is enabled by default with -fsanitize=address and 3222 disabled by default with -fsanitize=kernel-address. Compared to the 3223 LLVM compiler, where the option already exists, the implementation 3224 in the GCC compiler has some improvements and advantages: 3225 + Complex uses of gotos and case labels are properly handled and 3226 should not report any false positive or false negatives. 3227 + C++ temporaries are sanitized. 3228 + Sanitization can handle invalid memory stores that are 3229 optimized out by the LLVM compiler when optimization is 3230 enabled. 3231 * The -fsanitize=signed-integer-overflow suboption of the 3232 UndefinedBehavior Sanitizer now diagnoses arithmetic overflows even 3233 on arithmetic operations with generic vectors. 3234 * Version 5 of the [6]DWARF debugging information standard is 3235 supported through the -gdwarf-5 option. The DWARF version 4 3236 debugging information remains the default until consumers of 3237 debugging information are adjusted. 3238 3239 New Languages and Language specific improvements 3240 3241 OpenACC support in C, C++, and Fortran continues to be maintained and 3242 improved. See the [7]OpenACC and [8]Offloading wiki pages for further 3243 information. 3244 3245 Ada 3246 3247 * On mainstream native platforms, Ada programs no longer require the 3248 stack to be made executable in order to run properly. 3249 3250 BRIG (HSAIL) 3251 3252 Support for processing BRIG 1.0 files was added in this release. BRIG 3253 is a binary format for HSAIL (Heterogeneous System Architecture 3254 Intermediate Language). The BRIG front end can be used for implementing 3255 HSAIL "finalizers" (compilation of HSAIL to a native ISA) for 3256 GCC-supported targets. An implementation of an HSAIL runtime library, 3257 libhsail-rt is also included. 3258 3259 C family 3260 3261 * New command-line options have been added for the C and C++ 3262 compilers: 3263 + -Wimplicit-fallthrough warns when a switch case falls through. 3264 This warning has five different levels. The compiler is able 3265 to parse a wide range of fallthrough comments, depending on 3266 the level. It also handles control-flow statements, such as 3267 ifs. It's possible to suppress the warning by either adding a 3268 fallthrough comment, or by using a null statement: 3269 __attribute__ ((fallthrough)); (C, C++), or [[fallthrough]]; 3270 (C++17), or [[gnu::fallthrough]]; (C++11/C++14). This warning 3271 is enabled by -Wextra. 3272 + -Wpointer-compare warns when a pointer is compared with a zero 3273 character constant. Such code is now invalid in C++11 and GCC 3274 rejects it. This warning is enabled by default. 3275 + -Wduplicated-branches warns when an if-else has identical 3276 branches. 3277 + -Wrestrict warns when an argument passed to a 3278 restrict-qualified parameter aliases with another argument. 3279 + -Wmemset-elt-size warns for memset calls, when the first 3280 argument references an array, and the third argument is a 3281 number equal to the number of elements of the array, but not 3282 the size of the array. This warning is enabled by -Wall. 3283 + -Wint-in-bool-context warns about suspicious uses of integer 3284 values where boolean values are expected. This warning is 3285 enabled by -Wall. 3286 + -Wswitch-unreachable warns when a switch statement has 3287 statements between the controlling expression and the first 3288 case label which will never be executed. This warning is 3289 enabled by default. 3290 + -Wexpansion-to-defined warns when defined is used outside #if. 3291 This warning is enabled by -Wextra or -Wpedantic. 3292 + -Wregister warns about uses of the register storage specifier. 3293 In C++17 this keyword has been removed and for C++17 this is a 3294 pedantic warning enabled by default. The warning is not 3295 emitted for the GNU Explicit Register Variables extension. 3296 + -Wvla-larger-than=N warns about unbounded uses of 3297 variable-length arrays, and about bounded uses of 3298 variable-length arrays whose bound can be larger than N bytes. 3299 + -Wduplicate-decl-specifier warns when a declaration has 3300 duplicate const, volatile, restrict or _Atomic specifier. This 3301 warning is enabled by -Wall. 3302 * GCC 6's C and C++ front ends were able to offer suggestions for 3303 misspelled field names: 3304 3305 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 3306 you mean 'color'? 3307 return ptr->colour; 3308 ^~~~~~ 3309 3310 GCC 7 greatly expands the scope of these suggestions. Firstly, it 3311 adds fix-it hints to such suggestions: 3312 3313 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 3314 you mean 'color'? 3315 return ptr->colour; 3316 ^~~~~~ 3317 color 3318 3319 The suggestions now cover many other things, such as misspelled 3320 function names: 3321 3322 spellcheck-identifiers.c:11:3: warning: implicit declaration of function 'gtk_wi 3323 dget_showall'; did you mean 'gtk_widget_show_all'? [-Wimplicit-function-declarat 3324 ion] 3325 gtk_widget_showall (w); 3326 ^~~~~~~~~~~~~~~~~~ 3327 gtk_widget_show_all 3328 3329 misspelled macro names and enum values: 3330 3331 spellcheck-identifiers.cc:85:11: error: 'MAX_ITEM' undeclared here (not in a fun 3332 ction); did you mean 'MAX_ITEMS'? 3333 int array[MAX_ITEM]; 3334 ^~~~~~~~ 3335 MAX_ITEMS 3336 3337 misspelled type names: 3338 3339 spellcheck-typenames.c:7:14: error: unknown type name 'singed'; did you mean 'si 3340 gned'? 3341 void test (singed char e); 3342 ^~~~~~ 3343 signed 3344 3345 and, in the C front end, named initializers: 3346 3347 test.c:7:20: error: 'struct s' has no member named 'colour'; did you mean 'color 3348 '? 3349 struct s test = { .colour = 3 }; 3350 ^~~~~~ 3351 color 3352 3353 * The preprocessor can now offer suggestions for misspelled 3354 directives, e.g.: 3355 3356 test.c:5:2: error:invalid preprocessing directive #endfi; did you mean #endif? 3357 #endfi 3358 ^~~~~ 3359 endif 3360 3361 * Warnings about format strings now underline the pertinent part of 3362 the string, and can offer suggested fixes. In some cases, the 3363 pertinent argument is underlined. 3364 3365 test.c:51:29: warning: format '%s' expects argument of type 'char *', but argume 3366 nt 3 has type 'int' [-Wformat=] 3367 printf ("foo: %d bar: %s baz: %d", 100, i + j, 102); 3368 ~^ ~~~~~ 3369 %d 3370 3371 * The new -Wdangling-else command-line option has been split out of 3372 -Wparentheses and warns about dangling else. 3373 * The -Wshadow warning has been split into three variants. 3374 -Wshadow=global warns for any shadowing. This is the default when 3375 using -Wshadow without any argument. -Wshadow=local only warns for 3376 a local variable shadowing another local variable or parameter. 3377 -Wshadow=compatible-local only warns for a local variable shadowing 3378 another local variable or parameter whose type is compatible (in 3379 C++ compatible means that the type of the shadowing variable can be 3380 converted to that of the shadowed variable). 3381 The following example shows the different kinds of shadow warnings: 3382 3383 enum operation { add, count }; 3384 struct container { int nr; }; 3385 3386 int 3387 container_count (struct container c, int count) 3388 { 3389 int r = 0; 3390 for (int count = 0; count > 0; count--) 3391 { 3392 struct container count = c; 3393 r += count.nr; 3394 } 3395 return r; 3396 } 3397 3398 -Wshadow=compatible-local will warn for the parameter being 3399 shadowed with the same type: 3400 3401 warn-test.c:8:12: warning: declaration of 'count' shadows a parameter [-Wshadow= 3402 compatible-local] 3403 for (int count = 0; count > 0; count--) 3404 ^~~~~ 3405 warn-test.c:5:42: note: shadowed declaration is here 3406 container_count (struct container c, int count) 3407 ^~~~~ 3408 3409 -Wshadow=local will warn for the above and for the shadowed 3410 declaration with incompatible type: 3411 3412 warn-test.c:10:24: warning: declaration of 'count' shadows a previous local [-Ws 3413 hadow=local] 3414 struct container count = c; 3415 ^~~~~ 3416 warn-test.c:8:12: note: shadowed declaration is here 3417 for (int count = 0; count > 0; count--) 3418 ^~~~~ 3419 3420 -Wshadow=global will warn for all of the above and the shadowing of 3421 the global declaration: 3422 3423 warn-test.c:5:42: warning: declaration of 'count' shadows a global declaration [ 3424 -Wshadow] 3425 container_count (struct container c, int count) 3426 ^~~~~ 3427 warn-test.c:1:23: note: shadowed declaration is here 3428 enum operation { add, count }; 3429 ^~~~~ 3430 3431 * GCC 7 contains a number of enhancements that help detect buffer 3432 overflow and other forms of invalid memory accesses. 3433 + The -Walloc-size-larger-than=size option detects calls to 3434 standard and user-defined memory allocation functions 3435 decorated with attribute alloc_size whose argument exceeds the 3436 specified size (PTRDIFF_MAX by default). The option also 3437 detects arithmetic overflow in the computation of the size in 3438 two-argument allocation functions like calloc where the total 3439 size is the product of the two arguments. Since calls with an 3440 excessive size cannot succeed they are typically the result of 3441 programming errors. Such bugs have been known to be the source 3442 of security vulnerabilities and a target of exploits. 3443 -Walloc-size-larger-than=PTRDIFF_MAX is included in -Wall. 3444 For example, the following call to malloc incorrectly tries to 3445 avoid passing a negative argument to the function and instead 3446 ends up unconditionally invoking it with an argument less than 3447 or equal to zero. Since after conversion to the type of the 3448 argument of the function (size_t) a negative argument results 3449 in a value in excess of the maximum PTRDIFF_MAX the call is 3450 diagnosed. 3451 3452 void* f (int n) 3453 { 3454 return malloc (n > 0 ? 0 : n); 3455 } 3456 3457 warning: argument 1 range [2147483648, 4294967295] exceeds maximum object size 2 3458 147483647 [-Walloc-size-larger-than=] 3459 3460 + The -Walloc-zero option detects calls to standard and 3461 user-defined memory allocation functions decorated with 3462 attribute alloc_size with a zero argument. -Walloc-zero is not 3463 included in either -Wall or -Wextra and must be explicitly 3464 enabled. 3465 + The -Walloca option detects all calls to the alloca function 3466 in the program. -Walloca is not included in either -Wall or 3467 -Wextra and must be explicitly enabled. 3468 + The -Walloca-larger-than=size option detects calls to the 3469 alloca function whose argument either may exceed the specified 3470 size, or that is not known to be sufficiently constrained to 3471 avoid exceeding it. -Walloca-larger-than is not included in 3472 either -Wall or -Wextra and must be explicitly enabled. 3473 For example, compiling the following snippet with 3474 -Walloca-larger-than=1024 results in a warning because even 3475 though the code appears to call alloca only with sizes of 1kb 3476 and less, since n is signed, a negative value would result in 3477 a call to the function well in excess of the limit. 3478 3479 void f (int n) 3480 { 3481 char *d; 3482 if (n < 1025) 3483 d = alloca (n); 3484 else 3485 d = malloc (n); 3486 ... 3487 } 3488 3489 warning: argument to 'alloca may be too large due to conversion from 'int' to 'l 3490 ong unsigned int' [-Walloca-larger-than=] 3491 3492 In contrast, a call to alloca that isn't bounded at all such 3493 as in the following function will elicit the warning below 3494 regardless of the size argument to the option. 3495 3496 void f (size_t n) 3497 { 3498 char *d = alloca (n); 3499 ... 3500 } 3501 3502 warning: unbounded use of 'alloca' [-Walloca-larger-than=] 3503 3504 + The -Wformat-overflow=level option detects certain and likely 3505 buffer overflow in calls to the sprintf family of formatted 3506 output functions. Although the option is enabled even without 3507 optimization it works best with -O2 and higher. 3508 For example, in the following snippet the call to sprintf is 3509 diagnosed because even though its output has been constrained 3510 using the modulo operation it could result in as many as three 3511 bytes if mday were negative. The solution is to either 3512 allocate a larger buffer or make sure the argument is not 3513 negative, for example by changing mday's type to unsigned or 3514 by making the type of the second operand of the modulo 3515 expression unsigned: 100U. 3516 3517 void* f (int mday) 3518 { 3519 char *buf = malloc (3); 3520 sprintf (buf, "%02i", mday % 100); 3521 return buf; 3522 } 3523 3524 warning: 'sprintf may write a terminating nul past the end of the destination [- 3525 Wformat-overflow=] 3526 note: 'sprintf' output between 3 and 4 bytes into a destination of size 3 3527 3528 + The -Wformat-truncation=level option detects certain and 3529 likely output truncation in calls to the snprintf family of 3530 formatted output functions. -Wformat-truncation=1 is included 3531 in -Wall and enabled without optimization but works best with 3532 -O2 and higher. 3533 For example, the following function attempts to format an 3534 integer between 0 and 255 in hexadecimal, including the 0x 3535 prefix, into a buffer of four characters. But since the 3536 function must always terminate output by the null character 3537 ('\0') such a buffer is only big enough to fit just one digit 3538 plus the prefix. Therefore the snprintf call is diagnosed. To 3539 avoid the warning either use a bigger buffer or handle the 3540 function's return value which indicates whether or not its 3541 output has been truncated. 3542 3543 void f (unsigned x) 3544 { 3545 char d[4]; 3546 snprintf (d, sizeof d, "%#02x", x & 0xff); 3547 ... 3548 } 3549 3550 warning: 'snprintf' output may be truncated before the last format character [-W 3551 format-truncation=] 3552 note: 'snprintf' output between 3 and 5 bytes into a destination of size 4 3553 3554 + The -Wnonnull option has been enhanced to detect a broader set 3555 of cases of passing null pointers to functions that expect a 3556 non-null argument (those decorated with attribute nonnull). By 3557 taking advantage of optimizations the option can detect many 3558 more cases of the problem than in prior GCC versions. 3559 + The -Wstringop-overflow=type option detects buffer overflow in 3560 calls to string handling functions like memcpy and strcpy. The 3561 option relies on [9]Object Size Checking and has an effect 3562 similar to defining the _FORTIFY_SOURCE macro. 3563 -Wstringop-overflow=2 is enabled by default. 3564 For example, in the following snippet, because the call to 3565 strncat specifies a maximum that allows the function to write 3566 past the end of the destination, it is diagnosed. To correct 3567 the problem and avoid the overflow the function should be 3568 called with a size of at most sizeof d - strlen(d) - 1. 3569 3570 void f (const char *fname) 3571 { 3572 char d[8]; 3573 strncpy (d, "/tmp/", sizeof d); 3574 strncat (d, fname, sizeof d); 3575 ... 3576 } 3577 3578 warning: specified bound 8 equals the size of the destination [-Wstringop-overfl 3579 ow=] 3580 3581 * The <limits.h> header provided by GCC defines macros such as 3582 INT_WIDTH for the width in bits of integer types, if 3583 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 3584 included. The <stdint.h> header defines such macros as SIZE_WIDTH 3585 and INTMAX_WIDTH for the width of some standard typedef names for 3586 integer types, again if __STDC_WANT_IEC_60559_BFP_EXT__ is defined 3587 before the header is included; note that GCC's implementation of 3588 this header is only used for freestanding compilations, not hosted 3589 compilations, on most systems. These macros come from ISO/IEC TS 3590 18661-1:2014. 3591 * The <float.h> header provided by GCC defines the macro 3592 CR_DECIMAL_DIG, from ISO/IEC TS 18661-1:2014, if 3593 __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is 3594 included. This represents the number of decimal digits for which 3595 conversions between decimal character strings and binary formats, 3596 in both directions, are correctly rounded, and currently has the 3597 value of UINTMAX_MAX on all systems, reflecting that GCC's 3598 compile-time conversions are correctly rounded for any number of 3599 digits. 3600 * New __builtin_add_overflow_p, __builtin_sub_overflow_p, 3601 __builtin_mul_overflow_p built-in functions have been added. These 3602 work similarly to their siblings without the _p suffix, but do not 3603 actually store the result of the arithmetics anywhere, just return 3604 whether the operation would overflow. Calls to these built-ins with 3605 integer constant arguments evaluate to integer constants 3606 expressions. 3607 For example, in the following, c is assigned the result of a * b 3608 only if the multiplication does not overflow, otherwise it is 3609 assigned the value zero. The multiplication is performed at 3610 compile-time and without triggering a -Woverflow warning. 3611 3612 enum { 3613 a = 12345678, 3614 b = 87654321, 3615 c = __builtin_mul_overflow_p (a, b, a) ? 0 : a * b 3616 }; 3617 3618 C 3619 3620 * The C front end now supports type names _FloatN for floating-point 3621 types with IEEE interchange formats and _FloatNx for floating-point 3622 types with IEEE extended formats. These type names come from 3623 ISO/IEC TS 18661-3:2015. 3624 The set of types supported depends on the target for which GCC is 3625 configured. Most targets support _Float32, _Float32x and _Float64. 3626 _Float128 is supported on targets where IEEE binary128 encoding was 3627 already supported as long double or __float128. _Float64x is 3628 supported on targets where a type with either binary128 or Intel 3629 extended precision format is available. 3630 Constants with these types are supported using suffixes fN, FN, fNx 3631 and FNx (e.g., 1.2f128 or 2.3F64x). Macros such as FLT128_MAX are 3632 defined in <float.h> if __STDC_WANT_IEC_60559_TYPES_EXT__ is 3633 defined before it is included. 3634 These new types are always distinct from each other and from float, 3635 double and long double, even if they have the same encoding. 3636 Complex types such as _Complex _Float128 are also supported. 3637 Type-generic built-in functions such as __builtin_isinf support the 3638 new types, and the following type-specific built-in functions have 3639 versions (suffixed fN or fNx) for the new types: 3640 __builtin_copysign, __builtin_fabs, __builtin_huge_val, 3641 __builtin_inf, __builtin_nan, __builtin_nans. 3642 * Compilation with -fopenmp is now compatible with the C11 _Atomic 3643 keyword. 3644 3645 C++ 3646 3647 * The C++ front end has experimental support for all of the current 3648 C++17 draft with the -std=c++1z or -std=gnu++1z flags, including if 3649 constexpr, class template argument deduction, auto template 3650 parameters, and structured bindings. For a full list of new 3651 features, see [10]the C++ status page. 3652 * C++17 support for new of over-aligned types can be enabled in other 3653 modes with the -faligned-new flag. 3654 * The C++17 evaluation order requirements can be selected in other 3655 modes with the -fstrong-eval-order flag, or disabled in C++17 mode 3656 with -fno-strong-eval-order. 3657 * The default semantics of inherited constructors has changed in all 3658 modes, following [11]P0136. Essentially, overload resolution 3659 happens as if calling the inherited constructor directly, and the 3660 compiler fills in construction of the other bases and members as 3661 needed. Most uses should not need any changes. The old behavior can 3662 be restored with -fno-new-inheriting-ctors, or -fabi-version less 3663 than 11. 3664 * The resolution of DR 150 on matching of template template 3665 parameters, allowing default template arguments to make a template 3666 match a parameter, is currently enabled by default in C++17 mode 3667 only. The default can be overridden with -f{no-,}new-ttp-matching. 3668 * The C++ front end will now provide fix-it hints for some missing 3669 semicolons, allowing for automatic fixes by IDEs: 3670 3671 test.cc:4:11: error: expected ';' after class definition 3672 class a {} 3673 ^ 3674 ; 3675 3676 * -Waligned-new has been added to the C++ front end. It warns about 3677 new of type with extended alignment without -faligned-new. 3678 3679 Runtime Library (libstdc++) 3680 3681 * The type of exception thrown by iostreams, std::ios_base::failure, 3682 now uses the [12]cxx11 ABI. 3683 * Experimental support for C++17, including the following new 3684 features: 3685 + std::string_view; 3686 + std::any, std::optional, and std::variant; 3687 + std::invoke, std::is_invocable, std::is_nothrow_invocable, and 3688 invoke_result; 3689 + std::is_swappable, and std::is_nothrow_swappable; 3690 + std::apply, and std::make_from_tuple; 3691 + std::void_t, std::bool_constant, std::conjunction, 3692 std::disjunction, and std::negation; 3693 + Variable templates for type traits; 3694 + Mathematical Special Functions; 3695 + std::chrono::floor, std::chrono::ceil, std::chrono::round, and 3696 std::chrono::abs; 3697 + std::clamp, std::gcd, std::lcm, 3-dimensional std::hypot; 3698 + std::scoped_lock, std::shared_mutex, 3699 std::atomic<T>::is_always_lock_free; 3700 + std::sample, std::default_searcher, std::boyer_moore_searcher 3701 and std::boyer_moore_horspool_searcher; 3702 + Extraction and re-insertion of map and set nodes, try_emplace 3703 members for maps, and functions for accessing containers 3704 std::size, std::empty, and std::data; 3705 + std::shared_ptr support for arrays, 3706 std::shared_ptr<T>::weak_type, 3707 std::enable_shared_from_this<T>::weak_from_this(), and 3708 std::owner_less<void>; 3709 + std::byte; 3710 + std::as_const, std::not_fn, 3711 std::has_unique_object_representations, constexpr 3712 std::addressof. 3713 Thanks to Daniel Krgler, Tim Shen, Edward Smith-Rowland, and Ville 3714 Voutilainen for work on the C++17 support. 3715 * A new power-of-two rehashing policy for use with the _Hashtable 3716 internals, thanks to Franois Dumont. 3717 3718 Fortran 3719 3720 * Support for a number of extensions for compatibility with legacy 3721 code with new flags: 3722 + -fdec-structure Support for DEC STRUCTURE and UNION 3723 + -fdec-intrinsic-ints Support for new integer intrinsics with 3724 B/I/J/K prefixes such as BABS, JIAND... 3725 + -fdec-math Support for additional math intrinsics, including 3726 COTAN and degree-valued trigonometric functions such as TAND, 3727 ASIND... 3728 + -fdec Enable the -fdec-* family of extensions. 3729 * New flag -finit-derived to allow default initialization of 3730 derived-type variables. 3731 * Improved DO loops with step equal to 1 or -1, generates faster code 3732 without a loop preheader. A new warning, -Wundefined-do-loop, warns 3733 when a loop iterates either to HUGE(i) (with step equal to 1), or 3734 to -HUGE(i) (with step equal to -1). Invalid behavior can be caught 3735 at run time with -fcheck=do enabled: 3736 3737 program test 3738 implicit none 3739 integer(1) :: i 3740 do i = -HUGE(i)+10, -HUGE(i)-1, -1 3741 print *, i 3742 end do 3743 end program test 3744 3745 At line 8 of file do_check_12.f90 3746 Fortran runtime error: Loop iterates infinitely 3747 3748 * Version 4.5 of the [13]OpenMP specification is now partially 3749 supported in the Fortran compiler; the largest missing item is 3750 structure element mapping. 3751 * User-defined derived-type input/output (UDTIO) is added. 3752 * Derived type coarrays with allocatable and pointer components are 3753 partially supported. 3754 * Non-constant stop codes and error stop codes (Fortran 2015 3755 feature). 3756 * Derived types with allocatable components of recursive type. 3757 * Intrinsic assignment to polymorphic variables. 3758 * Improved submodule support. 3759 * Improved diagnostics (polymorphic results in pure functions). 3760 * Coarray: Support for failed images (Fortan 2015 feature). 3761 3762 Go 3763 3764 * GCC 7 provides a complete implementation of the Go 1.8.1 user 3765 packages. 3766 * Compared to the Go 1.8.1 toolchain, the garbage collector is more 3767 conservative and less concurrent. 3768 * Escape analysis is available for experimental use via the 3769 -fgo-optimize-allocs option. The -fgo-debug-escape prints 3770 information useful for debugging escape analysis choices. 3771 3772 Java (GCJ) 3773 3774 The GCC Java front end and associated libjava runtime library have been 3775 removed from GCC. 3776 3777 libgccjit 3778 3779 The libgccjit API gained support for marking calls as requiring 3780 tail-call optimization via a new entry point: 3781 [14]gcc_jit_rvalue_set_bool_require_tail_call. 3782 3783 libgccjit performs numerous checks at the API boundary, but if these 3784 succeed, it previously ignored errors and other diagnostics emitted 3785 within the core of GCC, and treated the compile of a gcc_jit_context as 3786 having succeeded. As of GCC 7 it now ensures that if any diagnostics 3787 are emitted, they are visible from the libgccjit API, and that the the 3788 context is flagged as having failed. 3789 3790 New Targets and Target Specific Improvements 3791 3792 AArch64 3793 3794 * GCC has been updated to the latest revision of the procedure call 3795 standard (AAPCS64) to provide support for parameter passing when 3796 data types have been over-aligned. 3797 * The ARMv8.3-A architecture is now supported. It can be used by 3798 specifying the -march=armv8.3-a option. 3799 * The option -msign-return-address= is supported to enable return 3800 address protection using ARMv8.3-A Pointer Authentication 3801 Extensions. For more information on the arguments accepted by this 3802 option, please refer to [15]AArch64-Options. 3803 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 3804 Extensions are now supported. They can be used by specifying the 3805 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 3806 Floating-Point Extensions introduce new half-precision data 3807 processing floating-point instructions. 3808 * Support has been added for the following processors (GCC 3809 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), Broadcom 3810 Vulcan (vulcan), Cavium ThunderX CN81xx (thunderxt81), Cavium 3811 ThunderX CN83xx (thunderxt83), Cavium ThunderX CN88xx 3812 (thunderxt88), Cavium ThunderX CN88xx pass 1.x (thunderxt88p1), 3813 Cavium ThunderX 2 CN99xx (thunderx2t99), Qualcomm Falkor (falkor). 3814 The GCC identifiers can be used as arguments to the -mcpu or -mtune 3815 options, for example: -mcpu=cortex-a73 or -mtune=vulcan or as 3816 arguments to the equivalent target attributes and pragmas. 3817 3818 ARC 3819 3820 * Added support for ARC HS and ARC EM processors. 3821 * Added support for ARC EM variation found in Intel QuarkSE SoCs. 3822 * Added support for NPS400 ARC700 based CPUs. 3823 * Thread Local Storage is now supported by ARC CPUs. 3824 * Fixed errors for ARC600 when using 32x16 multiplier option. 3825 * Fixed PIE for ARC CPUs. 3826 * New CPU templates are supported via multilib. 3827 3828 ARM 3829 3830 * Support for the ARMv5 and ARMv5E architectures has been deprecated 3831 (which have no known implementations) and will be removed in a 3832 future GCC release. Note that ARMv5T, ARMv5TE and ARMv5TEJ 3833 architectures remain supported. The values armv5 and armv5e of 3834 -march are thus deprecated. 3835 * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point 3836 Extensions are now supported. They can be used by specifying the 3837 -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit 3838 Floating-Point Extensions introduce new half-precision data 3839 processing floating-point instructions. 3840 * The ARMv8-M architecture is now supported in its two architecture 3841 profiles: ARMv8-M Baseline and ARMv8-M Mainline with its DSP and 3842 Floating-Point Extensions. They can be used by specifying the 3843 -march=armv8-m.base, armv8-m.main or armv8-m.main+dsp options. 3844 * Support has been added for the following processors (GCC 3845 identifiers in parentheses): ARM Cortex-A73 (cortex-a73), ARM 3846 Cortex-M23 (cortex-m23) and ARM Cortex-M33 (cortex-m33). The GCC 3847 identifiers can be used as arguments to the -mcpu or -mtune 3848 options, for example: -mcpu=cortex-a73 or -mtune=cortex-m33. 3849 * A new command-line option -mpure-code has been added. It does not 3850 allow constant data to be placed in code sections. This option is 3851 only available when generating non-PIC code for ARMv7-M targets. 3852 * Support for the ACLE Coprocessor Intrinsics has been added. This 3853 enables the generation of coprocessor instructions through the use 3854 of intrinsics such as cdp, ldc, and others. 3855 * The configure option --with-multilib-list now accepts the value 3856 rmprofile to build multilib libraries for a range of embedded 3857 targets. See our [16]installation instructions for details. 3858 3859 AVR 3860 3861 * On the reduced Tiny cores, the progmem [17]variable attribute is 3862 now properly supported. Respective read-only variables are located 3863 in flash memory in section .progmem.data. No special code is needed 3864 to access such variables; the compiler automatically adds an offset 3865 of 0x4000 to all addresses, which is needed to access variables in 3866 flash memory. As opposed to ordinary cores where it is sufficient 3867 to specify the progmem attribute with definitions, on the reduced 3868 Tiny cores the attribute also has to be specified with (external) 3869 declarations: 3870 3871 extern const int array[] __attribute__((__progmem__)); 3872 3873 int get_value2 (void) 3874 { 3875 /* Access via addresses array + 0x4004 and array + 0x4005. */ 3876 return array[2]; 3877 } 3878 3879 const int* get_address (unsigned idx) 3880 { 3881 /* Returns array + 0x4000 + 2 * idx. */ 3882 return &array[idx]; 3883 } 3884 3885 * A new command-line option -Wmisspelled-isr has been added. It turns 3886 off -- or turns into errors -- warnings that are reported for 3887 interrupt service routines (ISRs) which don't follow AVR-LibC's 3888 naming convention of prefixing ISR names with __vector. 3889 * __builtin_avr_nops(n) is a new [18]built-in function that inserts n 3890 NOP instructions into the instruction stream. n must be a value 3891 known at compile time. 3892 3893 IA-32/x86-64 3894 3895 * Support for the AVX-512 Fused Multiply Accumulation Packed Single 3896 precision (4FMAPS), AVX-512 Vector Neural Network Instructions Word 3897 variable precision (4VNNIW), AVX-512 Vector Population Count 3898 (VPOPCNTDQ) and Software Guard Extensions (SGX) ISA extensions has 3899 been added. 3900 3901 NVPTX 3902 3903 * OpenMP target regions can now be offloaded to NVidia PTX GPGPUs. 3904 See the [19]Offloading Wiki on how to configure it. 3905 3906 PowerPC / PowerPC64 / RS6000 3907 3908 * The PowerPC port now uses LRA by default. 3909 * GCC now diagnoses inline assembly that clobbers register r2. This 3910 has always been invalid code, and is no longer quietly tolerated. 3911 * The PowerPC port's support for ISA 3.0 (-mcpu=power9) has been 3912 enhanced to generate more of the new instructions by default, and 3913 to provide more built-in functions to generate code for other new 3914 instructions. 3915 * The configuration option --enable-gnu-indirect-function is now 3916 enabled by default on PowerPC GNU/Linux builds. 3917 * The PowerPC port will now allow 64-bit and 32-bit integer types to 3918 be allocated to the VSX vector registers (ISA 2.06 and above). In 3919 addition, on ISA 3.0, 16-bit and 8-bit integer types can be 3920 allocated in the vector registers. Previously, only 64-bit integer 3921 types were allowed in the traditional floating point registers. 3922 * New options -mstack-protector-guard=global, 3923 -mstack-protector-guard=tls, -mstack-protector-guard-reg=, and 3924 -mstack-protector-guard-offset= change how the stack protector gets 3925 the value to use as canary. 3926 3927 S/390, System z, IBM z Systems, IBM Z 3928 3929 * Support for the IBM z14 processor has been added. When using the 3930 -march=z14 option, the compiler will generate code making use of 3931 the new instructions introduced with the vector enhancement 3932 facility and the miscellaneous instruction extension facility 2. 3933 The -mtune=z14 option enables z14 specific instruction scheduling 3934 without making use of new instructions. 3935 * Builtins for the new vector instructions have been added and can be 3936 enabled using the -mzvector option. 3937 3938 RISC-V 3939 3940 * Support for the RISC-V instruction set has been added. 3941 3942 RX 3943 3944 Basic support for atomic built-in function has been added. It is 3945 currently implemented by flipping interrupts off and on as needed. 3946 3947 SH 3948 3949 * Support for SH5/SH64 has been removed. 3950 * Improved utilization of delay slots on SH2A. 3951 * Improved utilization of zero-displacement conditional branches. 3952 * The following deprecated options have been removed 3953 + -mcbranchdi 3954 + -mcmpeqdi 3955 + -minvalid-symbols 3956 + -msoft-atomic 3957 + -mspace 3958 + -madjust-unroll 3959 * Support for the following SH2A instructions has been added 3960 + mov.b @-Rm,R0 3961 + mov.w @-Rm,R0 3962 + mov.l @-Rm,R0 3963 + mov.b R0,@Rn+ 3964 + mov.w R0,@Rn+ 3965 + mov.l R0,@Rn+ 3966 3967 SPARC 3968 3969 * The SPARC port now uses LRA by default. 3970 * Support for the new Subtract-Extended-with-Carry instruction 3971 available in SPARC M7 (Niagara 7) has been added. 3972 3973 Operating Systems 3974 3975 AIX 3976 3977 * Visibility support has been enabled for AIX 7.1 and above. 3978 3979 Fuchsia 3980 3981 * Support has been added for the [20]Fuchsia OS. 3982 3983 RTEMS 3984 3985 * The ABI changes on ARM so that no short enums are used by default. 3986 3987 Other significant improvements 3988 3989 * -fverbose-asm previously emitted information on the meanings of 3990 assembly expressions. This has been extended so that it now also 3991 prints comments showing the source lines that correspond to the 3992 assembly, making it easier to read the generated assembly 3993 (especially with larger functions). For example, given this C 3994 source file: 3995 3996 int test (int n) 3997 { 3998 int i; 3999 int total = 0; 4000 4001 for (i = 0; i < n; i++) 4002 total += i * i; 4003 return total; 4004 } 4005 4006 -fverbose-asm now gives output similar to this for the function 4007 body (when compiling for x86_64, with -Os): 4008 4009 .text 4010 .globl test 4011 .type test, @@function 4012 test: 4013 .LFB0: 4014 .cfi_startproc 4015 # example.c:4: int total = 0; 4016 xorl %eax, %eax # <retval> 4017 # example.c:6: for (i = 0; i < n; i++) 4018 xorl %edx, %edx # i 4019 .L2: 4020 # example.c:6: for (i = 0; i < n; i++) 4021 cmpl %edi, %edx # n, i 4022 jge .L5 #, 4023 # example.c:7: total += i * i; 4024 movl %edx, %ecx # i, tmp92 4025 imull %edx, %ecx # i, tmp92 4026 # example.c:6: for (i = 0; i < n; i++) 4027 incl %edx # i 4028 # example.c:7: total += i * i; 4029 addl %ecx, %eax # tmp92, <retval> 4030 jmp .L2 # 4031 .L5: 4032 # example.c:10: } 4033 ret 4034 .cfi_endproc 4035 4036 * Two new options have been added for printing fix-it hints: 4037 + -fdiagnostics-parseable-fixits allows for fix-it hints to be 4038 emitted in a machine-readable form, suitable for consumption 4039 by IDEs. For example, given: 4040 4041 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 4042 you mean 'color'? 4043 return ptr->colour; 4044 ^~~~~~ 4045 color 4046 4047 it will emit: 4048 4049 fix-it:"spellcheck-fields.cc":{52:13-52:19}:"color" 4050 4051 + -fdiagnostics-generate-patch will print a patch in "unified" 4052 format after any diagnostics are printed, showing the result 4053 of applying all fix-it hints. For the above example it would 4054 emit: 4055 4056 --- spellcheck-fields.cc 4057 +++ spellcheck-fields.cc 4058 @@ -49,5 +49,5 @@ 4059 4060 color get_color(struct s *ptr) 4061 { 4062 - return ptr->colour; 4063 + return ptr->color; 4064 } 4065 4066 * The gcc and g++ driver programs will now provide suggestions for 4067 misspelled arguments to command-line options. 4068 4069 $ gcc -c test.c -ftls-model=global-dinamic 4070 gcc: error: unknown TLS model 'global-dinamic' 4071 gcc: note: valid arguments to '-ftls-model=' are: global-dynamic initial-exec lo 4072 cal-dynamic local-exec; did you mean 'global-dynamic'? 4073 4074 * The compiler will now provide suggestions for misspelled 4075 parameters. 4076 4077 $ gcc -c test.c --param max-early-inliner-iteration=3 4078 cc1: error: invalid --param name 'max-early-inliner-iteration'; did you mean 'ma 4079 x-early-inliner-iterations'? 4080 4081 * Profile-guided optimization (PGO) instrumentation, as well as test 4082 coverage (GCOV), can newly instrument constructors (functions marks 4083 with __attribute__((constructor))), destructors and C++ 4084 constructors (and destructors) of classes that are used as the type 4085 of a global variable. 4086 * A new option -fprofile-update=atomic prevents creation of corrupted 4087 profiles created during an instrumentation run (-fprofile=generate) 4088 of an application. The downside of the option is a speed penalty. 4089 Providing -pthread on the command line selects atomic profile 4090 updating (when supported by the target). 4091 * GCC's already extensive testsuite has gained some new capabilities, 4092 to further improve the reliability of the compiler: 4093 + GCC now has an internal unit-testing API and a suite of tests 4094 for programmatic self-testing of subsystems. 4095 + GCC's C front end has been extended so that it can parse dumps 4096 of GCC's internal representations, allowing for DejaGnu tests 4097 that more directly exercise specific optimization passes. This 4098 covers both the [21]GIMPLE representation (for testing 4099 higher-level optimizations) and the [22]RTL representation, 4100 allowing for more direct testing of lower-level details, such 4101 as register allocation and instruction selection. 4102 4103 GCC 7.1 4104 4105 This is the [23]list of problem reports (PRs) from GCC's bug tracking 4106 system that are known to be fixed in the 7.1 release. This list might 4107 not be complete (that is, it is possible that some PRs that have been 4108 fixed are not listed here). 4109 4110 GCC 7.2 4111 4112 This is the [24]list of problem reports (PRs) from GCC's bug tracking 4113 system that are known to be fixed in the 7.2 release. This list might 4114 not be complete (that is, it is possible that some PRs that have been 4115 fixed are not listed here). 4116 4117 Target Specific Changes 4118 4119 SPARC 4120 4121 * Support for the SPARC M8 processor has been added. 4122 * The switches -mfix-ut700 and -mfix-gr712rc have been added to work 4123 around an erratum in LEON3FT processors. 4124 * Use of the Floating-point Multiply Single to Double (FsMULd) 4125 instruction can now be controlled by the -mfsmuld and -fno-fsmuld 4126 options. 4127 4128 Operating Systems 4129 4130 RTEMS 4131 4132 * The Ada run-time support uses now thread-local storage (TLS). 4133 * Support for RISC-V has been added. 4134 * Support for 64-bit PowerPC using the ELFv2 ABI with 64-bit long 4135 double has been added. 4136 4137 GCC 7.3 4138 4139 This is the [25]list of problem reports (PRs) from GCC's bug tracking 4140 system that are known to be fixed in the 7.3 release. This list might 4141 not be complete (that is, it is possible that some PRs that have been 4142 fixed are not listed here). 4143 4144 Target Specific Changes 4145 4146 SPARC 4147 4148 * Workarounds for the four [26]LEON3FT errata GRLIB-TN-0010..0013 4149 have been added. Relevant errata are activated by the target 4150 specific -mfix-ut699, -mfix-ut700 and -mfix-gr712rc switches. 4151 4152 Operating Systems 4153 4154 RTEMS 4155 4156 * Support has been added for Epiphany target. 4157 4158 GCC 7.4 4159 4160 This is the [27]list of problem reports (PRs) from GCC's bug tracking 4161 system that are known to be fixed in the 7.4 release. This list might 4162 not be complete (that is, it is possible that some PRs that have been 4163 fixed are not listed here). 4164 4165 GCC 7.5 4166 4167 This is the [28]list of problem reports (PRs) from GCC's bug tracking 4168 system that are known to be fixed in the 7.5 release. This list might 4169 not be complete (that is, it is possible that some PRs that have been 4170 fixed are not listed here). 4171 4172 4173 For questions related to the use of GCC, please consult these web 4174 pages and the [29]GCC manuals. If that fails, the 4175 [30]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 4176 web pages and the development of GCC are welcome on our developer 4177 list at [31]gcc (a] gcc.gnu.org. All of [32]our lists have public 4178 archives. 4179 4180 Copyright (C) [33]Free Software Foundation, Inc. Verbatim copying and 4181 distribution of this entire article is permitted in any medium, 4182 provided this notice is preserved. 4183 4184 These pages are [34]maintained by the GCC team. Last modified 4185 2020-04-07[35]. 4186 4187 References 4188 4189 1. http://gcc.gnu.org/gcc-7/porting_to.html 4190 2. http://gcc.gnu.org/onlinedocs/index.html#current 4191 3. https://gcc.gnu.org/wiki/LRAIsDefault 4192 4. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/manual/profile_mode.html 4193 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728 4194 6. http://www.dwarfstd.org/Download.php 4195 7. https://gcc.gnu.org/wiki/OpenACC 4196 8. https://gcc.gnu.org/wiki/Offloading 4197 9. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Object-Size-Checking.html 4198 10. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 4199 11. https://wg21.link/p0136 4200 12. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/using_dual_abi.html 4201 13. https://www.openmp.org/specifications/ 4202 14. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/jit/topics/expressions.html#gcc_jit_rvalue_set_bool_require_tail_call 4203 15. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AArch64-Options.html#AArch64-Options 4204 16. https://gcc.gnu.org/install/configure.html 4205 17. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Variable-Attributes.html 4206 18. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Built-in-Functions.html 4207 19. https://gcc.gnu.org/wiki/Offloading 4208 20. https://fuchsia.googlesource.com/ 4209 21. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/GIMPLE-Tests.html 4210 22. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/RTL-Tests.html 4211 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.0 4212 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.2 4213 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.3 4214 26. https://www.gaisler.com/index.php/information/app-tech-notes 4215 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.4 4216 28. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.5 4217 29. https://gcc.gnu.org/onlinedocs/ 4218 30. mailto:gcc-help (a] gcc.gnu.org 4219 31. mailto:gcc (a] gcc.gnu.org 4220 32. https://gcc.gnu.org/lists.html 4221 33. https://www.fsf.org/ 4222 34. https://gcc.gnu.org/about.html 4223 35. http://validator.w3.org/check/referer 4224 ====================================================================== 4225 http://gcc.gnu.org/gcc-6/index.html 4226 4227 GCC 6 Release Series 4228 4229 (This release series is no longer supported.) 4230 4231 October 26, 2018 4232 4233 The [1]GNU project and the GCC developers are pleased to announce the 4234 release of GCC 6.5. 4235 4236 This release is a bug-fix release, containing fixes for regressions in 4237 GCC 6.4 relative to previous releases of GCC. 4238 4239 Release History 4240 4241 GCC 6.5 4242 October 26, 2018 ([2]changes, [3]documentation) 4243 4244 GCC 6.4 4245 July 4, 2017 ([4]changes, [5]documentation) 4246 4247 GCC 6.3 4248 December 21, 2016 ([6]changes, [7]documentation) 4249 4250 GCC 6.2 4251 August 22, 2016 ([8]changes, [9]documentation) 4252 4253 GCC 6.1 4254 April 27, 2016 ([10]changes, [11]documentation) 4255 4256 References and Acknowledgements 4257 4258 GCC used to stand for the GNU C Compiler, but since the compiler 4259 supports several other languages aside from C, it now stands for the 4260 GNU Compiler Collection. 4261 4262 A list of [12]successful builds is updated as new information becomes 4263 available. 4264 4265 The GCC developers would like to thank the numerous people that have 4266 contributed new features, improvements, bug fixes, and other changes as 4267 well as test results to GCC. This [13]amazing group of volunteers is 4268 what makes GCC successful. 4269 4270 For additional information about GCC please refer to the [14]GCC 4271 project web site or contact the [15]GCC development mailing list. 4272 4273 To obtain GCC please use [16]our mirror sites or [17]our version 4274 control system. 4275 4276 4277 For questions related to the use of GCC, please consult these web 4278 pages and the [18]GCC manuals. If that fails, the 4279 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 4280 web pages and the development of GCC are welcome on our developer 4281 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 4282 archives. 4283 4284 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 4285 distribution of this entire article is permitted in any medium, 4286 provided this notice is preserved. 4287 4288 These pages are [23]maintained by the GCC team. Last modified 4289 2020-01-14[24]. 4290 4291 References 4292 4293 1. http://www.gnu.org/ 4294 2. http://gcc.gnu.org/gcc-6/changes.html 4295 3. http://gcc.gnu.org/onlinedocs/6.5.0/ 4296 4. http://gcc.gnu.org/gcc-6/changes.html 4297 5. http://gcc.gnu.org/onlinedocs/6.4.0/ 4298 6. http://gcc.gnu.org/gcc-6/changes.html 4299 7. http://gcc.gnu.org/onlinedocs/6.3.0/ 4300 8. http://gcc.gnu.org/gcc-6/changes.html 4301 9. http://gcc.gnu.org/onlinedocs/6.2.0/ 4302 10. http://gcc.gnu.org/gcc-6/changes.html 4303 11. http://gcc.gnu.org/onlinedocs/6.1.0/ 4304 12. http://gcc.gnu.org/gcc-6/buildstat.html 4305 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 4306 14. http://gcc.gnu.org/index.html 4307 15. mailto:gcc (a] gcc.gnu.org 4308 16. http://gcc.gnu.org/mirrors.html 4309 17. http://gcc.gnu.org/git.html 4310 18. https://gcc.gnu.org/onlinedocs/ 4311 19. mailto:gcc-help (a] gcc.gnu.org 4312 20. mailto:gcc (a] gcc.gnu.org 4313 21. https://gcc.gnu.org/lists.html 4314 22. https://www.fsf.org/ 4315 23. https://gcc.gnu.org/about.html 4316 24. http://validator.w3.org/check/referer 4317 ====================================================================== 4318 http://gcc.gnu.org/gcc-6/changes.html 4319 4320 GCC 6 Release Series 4321 Changes, New Features, and Fixes 4322 4323 This page is a brief summary of some of the huge number of improvements 4324 in GCC 6. For more information, see the [1]Porting to GCC 6 page and 4325 the [2]full GCC documentation. 4326 4327 Caveats 4328 4329 * The default mode for C++ is now -std=gnu++14 instead of 4330 -std=gnu++98. 4331 * Support for a number of older systems and recently unmaintained or 4332 untested target ports of GCC has been declared obsolete in GCC 6. 4333 Unless there is activity to revive them, the next release of GCC 4334 will have their sources permanently removed. 4335 The following ports for individual systems on particular 4336 architectures have been obsoleted: 4337 + SH5 / SH64 (sh64-*-*) as announced [3]here. 4338 * The AVR port requires binutils version 2.26.1 or later for the fix 4339 for [4]PR71151 to work. 4340 * The GCC 6.5 release has an accidental ABI incompatibility for 4341 nested std::pair objects, for more details see [5]PR 87822. The bug 4342 causes a layout change for pairs where the first member is also a 4343 pair, e.g. std::pair<std::pair<X, Y>, Z>. The GCC 6 release series 4344 is closed so the bug in GCC 6.5 will not be fixed upstream, but 4345 there is a patch in the bug report to allow it to be fixed by 4346 anybody packaging GCC 6.5 or installing it themselves. 4347 4348 General Optimizer Improvements 4349 4350 * UndefinedBehaviorSanitizer gained a new sanitization option, 4351 -fsanitize=bounds-strict, which enables strict checking of array 4352 bounds. In particular, it enables -fsanitize=bounds as well as 4353 instrumentation of flexible array member-like arrays. 4354 * Type-based alias analysis now disambiguates accesses to different 4355 pointers. This improves precision of the alias oracle by about 4356 20-30% on higher-level C++ programs. Programs doing invalid type 4357 punning of pointer types may now need -fno-strict-aliasing to work 4358 correctly. 4359 * Alias analysis now correctly supports the weakref and alias 4360 attributes. This allows accessing both a variable and its alias in 4361 one translation unit which is common with link-time optimization. 4362 * Value range propagation now assumes that the this pointer in C++ 4363 member functions is non-null. This eliminates common null pointer 4364 checks but also breaks some non-conforming code-bases (such as 4365 Qt-5, Chromium, KDevelop). As a temporary work-around 4366 -fno-delete-null-pointer-checks can be used. Wrong code can be 4367 identified by using -fsanitize=undefined. 4368 * Link-time optimization improvements: 4369 + warning and error attributes are now correctly preserved by 4370 declaration linking and thus -D_FORTIFY_SOURCE=2 is now 4371 supported with -flto. 4372 + Type merging was fixed to handle C and Fortran 4373 interoperability rules as defined by the Fortran 2008 language 4374 standard. 4375 As an exception, CHARACTER(KIND=C_CHAR) is not inter-operable 4376 with char in all cases because it is an array while char is 4377 scalar. INTEGER(KIND=C_SIGNED_CHAR) should be used instead. In 4378 general, this inter-operability cannot be implemented, for 4379 example on targets where the argument passing convention for 4380 arrays differs from scalars. 4381 + More type information is now preserved at link time, reducing 4382 the loss of accuracy of the type-based alias analysis compared 4383 to builds without link-time optimization. 4384 + Invalid type punning on global variables and declarations is 4385 now reported with -Wodr-type-mismatch. 4386 + The size of LTO object files was reduced by about 11% 4387 (measured by compiling Firefox 46.0). 4388 + Link-time parallelization (enabled using -flto=n) was 4389 significantly improved by decreasing the size of streamed data 4390 when partitioning programs. The size of streamed IL while 4391 compiling Firefox 46.0 was reduced by 66%. 4392 + The linker plugin was extended to pass information about the 4393 type of binary produced to the GCC back end. (That can also be 4394 controlled manually by -flinker-output.) This makes it 4395 possible to properly configure the code generator and support 4396 incremental linking. Incremental linking of LTO objects by gcc 4397 -r is now supported for plugin-enabled setups. 4398 There are two ways to perform incremental linking: 4399 1. Linking by ld -r will result in an object file with all 4400 sections from individual object files mechanically 4401 merged. This delays the actual link-time optimization to 4402 the final linking step and thus permits whole program 4403 optimization. Linking the final binary with such object 4404 files is however slower. 4405 2. Linking by gcc -r will lead to link-time optimization and 4406 emit the final binary into the object file. Linking such 4407 an object file is fast but avoids any benefits from whole 4408 program optimization. 4409 GCC 7 will support incremental link-time optimization with gcc 4410 -r. 4411 * Inter-procedural optimization improvements: 4412 + Basic jump threading is now performed before profile 4413 construction and inline analysis, resulting in more realistic 4414 size and time estimates that drive the heuristics of the 4415 inliner and function cloning passes. 4416 + Function cloning now more aggressively eliminates unused 4417 function parameters. 4418 4419 New Languages and Language specific improvements 4420 4421 Compared to GCC 5, the GCC 6 release series includes a much improved 4422 implementation of the [6]OpenACC 2.0a specification. Highlights are: 4423 * In addition to single-threaded host-fallback execution, offloading 4424 is supported for nvptx (Nvidia GPUs) on x86_64 and PowerPC 64-bit 4425 little-endian GNU/Linux host systems. For nvptx offloading, with 4426 the OpenACC parallel construct, the execution model allows for an 4427 arbitrary number of gangs, up to 32 workers, and 32 vectors. 4428 * Initial support for parallelized execution of OpenACC kernels 4429 constructs: 4430 + Parallelization of a kernels region is switched on by 4431 -fopenacc combined with -O2 or higher. 4432 + Code is offloaded onto multiple gangs, but executes with just 4433 one worker, and a vector length of 1. 4434 + Directives inside a kernels region are not supported. 4435 + Loops with reductions can be parallelized. 4436 + Only kernels regions with one loop nest are parallelized. 4437 + Only the outer-most loop of a loop nest can be parallelized. 4438 + Loop nests containing sibling loops are not parallelized. 4439 Typically, using the OpenACC parallel construct gives much better 4440 performance, compared to the initial support of the OpenACC kernels 4441 construct. 4442 * The device_type clause is not supported. The bind and nohost 4443 clauses are not supported. The host_data directive is not supported 4444 in Fortran. 4445 * Nested parallelism (cf. CUDA dynamic parallelism) is not supported. 4446 * Usage of OpenACC constructs inside multithreaded contexts (such as 4447 created by OpenMP, or pthread programming) is not supported. 4448 * If a call to the acc_on_device function has a compile-time constant 4449 argument, the function call evaluates to a compile-time constant 4450 value only for C and C++ but not for Fortran. 4451 4452 See the [7]OpenACC and [8]Offloading wiki pages for further 4453 information. 4454 4455 C family 4456 4457 * Version 4.5 of the [9]OpenMP specification is now supported in the 4458 C and C++ compilers. 4459 * The C and C++ compilers now support attributes on enumerators. For 4460 instance, it is now possible to mark enumerators as deprecated: 4461 4462 enum { 4463 newval, 4464 oldval __attribute__ ((deprecated ("too old"))) 4465 }; 4466 4467 * Source locations for the C and C++ compilers are now tracked as 4468 ranges, rather than just points, making it easier to identify the 4469 subexpression of interest within a complicated expression. For 4470 example: 4471 4472 test.cc: In function 'int test(int, int, foo, int, int)': 4473 test.cc:5:16: error: no match for 'operator*' (operand types are 'int' and 'foo' 4474 ) 4475 return p + q * r * s + t; 4476 ~~^~~ 4477 4478 In addition, there is now initial support for precise diagnostic 4479 locations within strings: 4480 4481 format-strings.c:3:14: warning: field width specifier '*' expects a matching 'in 4482 t' argument [-Wformat=] 4483 printf("%*d"); 4484 ^ 4485 4486 * Diagnostics can now contain "fix-it hints", which are displayed in 4487 context underneath the relevant source code. For example: 4488 4489 fixits.c: In function 'bad_deref': 4490 fixits.c:11:13: error: 'ptr' is a pointer; did you mean to use '->'? 4491 return ptr.x; 4492 ^ 4493 -> 4494 4495 * The C and C++ compilers now offer suggestions for misspelled field 4496 names: 4497 4498 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did 4499 you mean 'color'? 4500 return ptr->colour; 4501 ^~~~~~ 4502 4503 * New command-line options have been added for the C and C++ 4504 compilers: 4505 + -Wshift-negative-value warns about left shifting a negative 4506 value. 4507 + -Wshift-overflow warns about left shift overflows. This 4508 warning is enabled by default. -Wshift-overflow=2 also warns 4509 about left-shifting 1 into the sign bit. 4510 + -Wtautological-compare warns if a self-comparison always 4511 evaluates to true or false. This warning is enabled by -Wall. 4512 + -Wnull-dereference warns if the compiler detects paths that 4513 trigger erroneous or undefined behavior due to dereferencing a 4514 null pointer. This option is only active when 4515 -fdelete-null-pointer-checks is active, which is enabled by 4516 optimizations in most targets. The precision of the warnings 4517 depends on the optimization options used. 4518 + -Wduplicated-cond warns about duplicated conditions in an 4519 if-else-if chain. 4520 + -Wmisleading-indentation warns about places where the 4521 indentation of the code gives a misleading idea of the block 4522 structure of the code to a human reader. For example, given 4523 [10]CVE-2014-1266: 4524 4525 sslKeyExchange.c: In function 'SSLVerifySignedServerKeyExchange': 4526 sslKeyExchange.c:629:3: warning: this 'if' clause does not guard... [-Wmisleadin 4527 g-indentation] 4528 if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0) 4529 ^~ 4530 sslKeyExchange.c:631:5: note: ...this statement, but the latter is misleadingly 4531 indented as if it is guarded by the 'if' 4532 goto fail; 4533 ^~~~ 4534 4535 This warning is enabled by -Wall. 4536 * The C and C++ compilers now emit saner error messages if 4537 merge-conflict markers are present in a source file. 4538 4539 test.c:3:1: error: version control conflict marker in file 4540 <<<<<<< HEAD 4541 ^~~~~~~ 4542 4543 C 4544 4545 * It is possible to disable warnings when an initialized field of a 4546 structure or a union with side effects is being overridden when 4547 using designated initializers via a new warning option 4548 -Woverride-init-side-effects. 4549 * A new type attribute scalar_storage_order applying to structures 4550 and unions has been introduced. It specifies the storage order (aka 4551 endianness) in memory of scalar fields in structures or unions. 4552 4553 C++ 4554 4555 * The default mode has been changed to -std=gnu++14. 4556 * [11]C++ Concepts are now supported when compiling with -fconcepts. 4557 * -flifetime-dse is more aggressive in dead-store elimination in 4558 situations where a memory store to a location precedes a 4559 constructor to that memory location. 4560 * G++ now supports [12]C++17 fold expressions, u8 character literals, 4561 extended static_assert, and nested namespace definitions. 4562 * G++ now allows constant evaluation for all non-type template 4563 arguments. 4564 * G++ now supports C++ Transactional Memory when compiling with 4565 -fgnu-tm. 4566 4567 Runtime Library (libstdc++) 4568 4569 * Extensions to the C++ Library to support mathematical special 4570 functions (ISO/IEC 29124:2010), thanks to Edward Smith-Rowland. 4571 * Experimental support for C++17, including the following new 4572 features: 4573 + std::uncaught_exceptions function (this is also available for 4574 -std=gnu++NN modes); 4575 + new member functions try_emplace and insert_or_assign for 4576 unique_key maps; 4577 + non-member functions std::size, std::empty, and std::data for 4578 accessing containers and arrays; 4579 + std::invoke; 4580 + std::shared_mutex; 4581 + std::void_t and std::bool_constant metaprogramming utilities. 4582 Thanks to Ville Voutilainen for contributing many of the C++17 4583 features. 4584 * An experimental implementation of the File System TS. 4585 * Experimental support for most features of the second version of the 4586 Library Fundamentals TS. This includes polymorphic memory resources 4587 and array support in shared_ptr, thanks to Fan You. 4588 * Some assertions checked by Debug Mode can now also be enabled by 4589 _GLIBCXX_ASSERTIONS. The subset of checks enabled by the new macro 4590 have less run-time overhead than the full _GLIBCXX_DEBUG checks and 4591 don't affect the library ABI, so can be enabled per-translation 4592 unit. 4593 * Timed mutex types are supported on more targets, including Darwin. 4594 * Improved std::locale support for DragonFly and FreeBSD, thanks to 4595 John Marino and Andreas Tobler. 4596 4597 Fortran 4598 4599 * Fortran 2008 SUBMODULE support. 4600 * Fortran 2015 EVENT_TYPE, EVENT_POST, EVENT_WAIT, and EVENT_QUERY 4601 support. 4602 * Improved support for Fortran 2003 deferred-length character 4603 variables. 4604 * Improved support for OpenMP and OpenACC. 4605 * The MATMUL intrinsic is now inlined for straightforward cases if 4606 front-end optimization is active. The maximum size for inlining can 4607 be set to n with the -finline-matmul-limit=n option and turned off 4608 with -finline-matmul-limit=0. 4609 * The -Wconversion-extra option will warn about REAL constants which 4610 have excess precision for their kind. 4611 * The -Winteger-division option has been added, which warns about 4612 divisions of integer constants which are truncated. This option is 4613 included in -Wall by default. 4614 4615 libgccjit 4616 4617 * The driver code is now run in-process within libgccjit, providing a 4618 small speed-up of the compilation process. 4619 * The API has gained entrypoints for 4620 + [13]timing how long was spent in different parts of code, 4621 + [14]creating switch statements, 4622 + [15]allowing unreachable basic blocks in a function, and 4623 + [16]adding arbitrary command-line options to a compilation. 4624 4625 New Targets and Target Specific Improvements 4626 4627 AArch64 4628 4629 * A number of AArch64-specific options have been added. The most 4630 important ones are summarised in this section; for more detailed 4631 information please refer to the documentation. 4632 * The command-line options -march=native, -mcpu=native and 4633 -mtune=native are now available on native AArch64 GNU/Linux 4634 systems. Specifying these options causes GCC to auto-detect the 4635 host CPU and choose the optimal setting for that system. 4636 * -fpic is now supported when generating code for the small code 4637 model (-mcmodel=small). The size of the global offset table (GOT) 4638 is limited to 28KiB under the LP64 SysV ABI, and 15KiB under the 4639 ILP32 SysV ABI. 4640 * The AArch64 port now supports target attributes and pragmas. Please 4641 refer to the [17]documentation for details of available attributes 4642 and pragmas as well as usage instructions. 4643 * Link-time optimization across translation units with different 4644 target-specific options is now supported. 4645 * The option -mtls-size= is now supported. It can be used to specify 4646 the bit size of TLS offsets, allowing GCC to generate better TLS 4647 instruction sequences. 4648 * The option -fno-plt is now fully functional. 4649 * The ARMv8.1-A architecture and the Large System Extensions are now 4650 supported. They can be used by specifying the -march=armv8.1-a 4651 option. Additionally, the +lse option extension can be used in a 4652 similar fashion to other option extensions. The Large System 4653 Extensions introduce new instructions that are used in the 4654 implementation of atomic operations. 4655 * The ACLE half-precision floating-point type __fp16 is now supported 4656 in the C and C++ languages. 4657 * The ARM Cortex-A35 processor is now supported via the 4658 -mcpu=cortex-a35 and -mtune=cortex-a35 options as well as the 4659 equivalent target attributes and pragmas. 4660 * The Qualcomm QDF24xx processor is now supported via the 4661 -mcpu=qdf24xx and -mtune=qdf24xx options as well as the equivalent 4662 target attributes and pragmas. 4663 * Code generation for the ARM Cortex-A57 processor is improved. Among 4664 general code generation improvements, a better algorithm is added 4665 for allocating registers to floating-point multiply-accumulate 4666 instructions offering increased performance when compiling with 4667 -mcpu=cortex-a57 or -mtune=cortex-a57. 4668 * Code generation for the ARM Cortex-A53 processor is improved. A 4669 more accurate instruction scheduling model for the processor is now 4670 used, and a number of compiler tuning parameters have been set to 4671 offer increased performance when compiling with -mcpu=cortex-a53 or 4672 -mtune=cortex-a53. 4673 * Code generation for the Samsung Exynos M1 processor is improved. A 4674 more accurate instruction scheduling model for the processor is now 4675 used, and a number of compiler tuning parameters have been set to 4676 offer increased performance when compiling with -mcpu=exynos-m1 or 4677 -mtune=exynos-m1. 4678 * Improvements in the generation of conditional branches and literal 4679 pools allow the compiler to compile functions of a large size. 4680 Constant pools are now placed into separate rodata sections. The 4681 new option -mpc-relative-literal-loads generates per-function 4682 literal pools, limiting the maximum size of functions to 1MiB. 4683 * Several correctness issues generating Advanced SIMD instructions 4684 for big-endian targets have been fixed resulting in improved code 4685 generation for ACLE intrinsics with -mbig-endian. 4686 4687 ARM 4688 4689 * Support for revisions of the ARM architecture prior to ARMv4t has 4690 been deprecated and will be removed in a future GCC release. The 4691 -mcpu and -mtune values that are deprecated are: arm2, arm250, 4692 arm3, arm6, arm60, arm600, arm610, arm620, arm7, arm7d, arm7di, 4693 arm70, arm700, arm700i, arm710, arm720, arm710c, arm7100, arm7500, 4694 arm7500fe, arm7m, arm7dm, arm7dmi, arm8, arm810, strongarm, 4695 strongarm110, strongarm1100, strongarm1110, fa526, fa626. The value 4696 arm7tdmi is still supported. The values of -march that are 4697 deprecated are: armv2,armv2a,armv3,armv3m,armv4. 4698 * The ARM port now supports target attributes and pragmas. Please 4699 refer to the [18]documentation for details of available attributes 4700 and pragmas as well as usage instructions. 4701 * Support has been added for the following processors (GCC 4702 identifiers in parentheses): ARM Cortex-A32 (cortex-a32), ARM 4703 Cortex-A35 (cortex-a35) and ARM Cortex-R8 (cortex-r8). The GCC 4704 identifiers can be used as arguments to the -mcpu or -mtune 4705 options, for example: -mcpu=cortex-a32 or -mtune=cortex-a35. 4706 4707 Heterogeneous Systems Architecture 4708 4709 * GCC can now generate HSAIL (Heterogeneous System Architecture 4710 Intermediate Language) for simple OpenMP device constructs if 4711 configured with --enable-offload-targets=hsa. A new libgomp plugin 4712 then runs the HSA GPU kernels implementing these constructs on HSA 4713 capable GPUs via a standard HSA run time. 4714 If the HSA compilation back end determines it cannot output HSAIL 4715 for a particular input, it gives a warning by default. These 4716 warnings can be suppressed with -Wno-hsa. To give a few examples, 4717 the HSA back end does not implement compilation of code using 4718 function pointers, automatic allocation of variable sized arrays, 4719 functions with variadic arguments as well as a number of other less 4720 common programming constructs. 4721 When compilation for HSA is enabled, the compiler attempts to 4722 compile composite OpenMP constructs 4723 4724 #pragma omp target teams distribute parallel for 4725 4726 into parallel HSA GPU kernels. 4727 4728 IA-32/x86-64 4729 4730 * GCC now supports the Intel CPU named Skylake with AVX-512 4731 extensions through -march=skylake-avx512. The switch enables the 4732 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 4733 AVX-512DQ. 4734 * Support for new AMD instructions monitorx and mwaitx has been 4735 added. This includes new intrinsic and built-in support. It is 4736 enabled through option -mmwaitx. The instructions monitorx and 4737 mwaitx implement the same functionality as the old monitor and 4738 mwait instructions. In addition mwaitx adds a configurable timer. 4739 The timer value is received as third argument and stored in 4740 register %ebx. 4741 * x86-64 targets now allow stack realignment from a word-aligned 4742 stack pointer using the command-line option -mstackrealign or 4743 __attribute__ ((force_align_arg_pointer)). This allows functions 4744 compiled with a vector-aligned stack to be invoked from objects 4745 that keep only word-alignment. 4746 * Support for address spaces __seg_fs, __seg_gs, and __seg_tls. These 4747 can be used to access data via the %fs and %gs segments without 4748 having to resort to inline assembly. Please refer to the 4749 [19]documentation for usage instructions. 4750 * Support for AMD Zen (family 17h) processors is now available 4751 through the -march=znver1 and -mtune=znver1 options. 4752 4753 MeP 4754 4755 * Support for the MeP (mep-elf) architecture has been deprecated and 4756 will be removed in a future GCC release. 4757 4758 MSP430 4759 4760 * The MSP430 compiler now has the ability to automatically distribute 4761 code and data between low memory (addresses below 64K) and high 4762 memory. This only applies to parts that actually have both memory 4763 regions and only if the linker script for the part has been 4764 specifically set up to support this feature. 4765 A new attribute of either can be applied to both functions and 4766 data, and this tells the compiler to place the object into low 4767 memory if there is room and into high memory otherwise. Two other 4768 new attributes - lower and upper - can be used to explicitly state 4769 that an object should be placed in the specified memory region. If 4770 there is not enough left in that region the compilation will fail. 4771 Two new command-line options - -mcode-region=[lower|upper|either] 4772 and -mdata-region=[lower|upper|either] - can be used to tell the 4773 compiler what to do with objects that do not have one of these new 4774 attributes. 4775 4776 PowerPC / PowerPC64 / RS6000 4777 4778 * PowerPC64 now supports IEEE 128-bit floating-point using the 4779 __float128 data type. In GCC 6, this is not enabled by default, but 4780 you can enable it with -mfloat128. The IEEE 128-bit floating-point 4781 support requires the use of the VSX instruction set. IEEE 128-bit 4782 floating-point values are passed and returned as a single vector 4783 value. The software emulator for IEEE 128-bit floating-point 4784 support is only built on PowerPC GNU/Linux systems where the 4785 default CPU is at least power7. On future ISA 3.0 systems (POWER 9 4786 and later), you will be able to use the -mfloat128-hardware option 4787 to use the ISA 3.0 instructions that support IEEE 128-bit 4788 floating-point. An additional type (__ibm128) has been added to 4789 refer to the IBM extended double type that normally implements long 4790 double. This will allow for a future transition to implementing 4791 long double with IEEE 128-bit floating-point. 4792 * Basic support has been added for POWER9 hardware that will use the 4793 recently published OpenPOWER ISA 3.0 instructions. The following 4794 new switches are available: 4795 + -mcpu=power9: Implement all of the ISA 3.0 instructions 4796 supported by the compiler. 4797 + -mtune=power9: In the future, apply tuning for POWER9 systems. 4798 Currently, POWER8 tunings are used. 4799 + -mmodulo: Generate code using the ISA 3.0 integer instructions 4800 (modulus, count trailing zeros, array index support, integer 4801 multiply/add). 4802 + -mpower9-fusion: Generate code to suitably fuse instruction 4803 sequences for a POWER9 system. 4804 + -mpower9-dform: Generate code to use the new D-form 4805 (register+offset) memory instructions for the vector 4806 registers. 4807 + -mpower9-vector: Generate code using the new ISA 3.0 vector 4808 (VSX or Altivec) instructions. 4809 + -mpower9-minmax: Reserved for future development. 4810 + -mtoc-fusion: Keep TOC entries together to provide more fusion 4811 opportunities. 4812 * New constraints have been added to support IEEE 128-bit 4813 floating-point and ISA 3.0 instructions: 4814 + wb: Altivec register if -mpower9-dform is enabled. 4815 + we: VSX register if -mpower9-vector is enabled for 64-bit code 4816 generation. 4817 + wo: VSX register if -mpower9-vector is enabled. 4818 + wp: Reserved for future use if long double is implemented with 4819 IEEE 128-bit floating-point instead of IBM extended double. 4820 + wq: VSX register if -mfloat128 is enabled. 4821 + wF: Memory operand suitable for POWER9 fusion load/store. 4822 + wG: Memory operand suitable for TOC fusion memory references. 4823 + wL: Integer constant identifying the element number mfvsrld 4824 accesses within a vector. 4825 * Support has been added for __builtin_cpu_is() and 4826 __builtin_cpu_supports(), allowing for very fast access to 4827 AT_PLATFORM, AT_HWCAP, and AT_HWCAP2 values. This requires use of 4828 glibc 2.23 or later. 4829 * All hardware transactional memory builtins now correctly behave as 4830 memory barriers. Programmers can use #ifdef __TM_FENCE__ to 4831 determine whether their "old" compiler treats the builtins as 4832 barriers. 4833 * Split-stack support has been added for gccgo on PowerPC64 for both 4834 big- and little-endian (but not for 32-bit). The gold linker from 4835 at least binutils 2.25.1 must be available in the PATH when 4836 configuring and building gccgo to enable split stack. (The 4837 requirement for binutils 2.25.1 applies to PowerPC64 only.) The 4838 split-stack feature allows a small initial stack size to be 4839 allocated for each goroutine, which increases as needed. 4840 * GCC on PowerPC now supports the standard lround function. 4841 * A new configuration option ---with-advance-toolchain=at was added 4842 for PowerPC 64-bit GNU/Linux systems to use the header files, 4843 library files, and the dynamic linker from a specific Advance 4844 Toolchain release instead of the default versions that are provided 4845 by the GNU/Linux distribution. In general, this option is intended 4846 for the developers of GCC, and it is not intended for general use. 4847 * The "q", "S", "T", and "t" asm-constraints have been removed. 4848 * The "b", "B", "m", "M", and "W" format modifiers have been removed. 4849 4850 S/390, System z, IBM z Systems 4851 4852 * Support for the IBM z13 processor has been added. When using the 4853 -march=z13 option, the compiler will generate code making use of 4854 the new instructions and registers introduced with the vector 4855 extension facility. The -mtune=z13 option enables z13 specific 4856 instruction scheduling without making use of new instructions. 4857 Compiling code with -march=z13 reduces the default alignment of 4858 vector types bigger than 8 bytes to 8. This is an ABI change and 4859 care must be taken when linking modules compiled with different 4860 arch levels which interchange variables containing vector type 4861 values. For newly compiled code the GNU linker will emit a warning. 4862 * The -mzvector option enables a C/C++ language extension. This 4863 extension provides a new keyword vector which can be used to define 4864 vector type variables. (Note: This is not available when enforcing 4865 strict standard compliance e.g. with -std=c99. Either enable GNU 4866 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 4867 Additionally a set of overloaded builtins is provided which is 4868 partially compatible to the PowerPC Altivec builtins. In order to 4869 make use of these builtins the vecintrin.h header file needs to be 4870 included. 4871 * The new command-line options -march=native, and -mtune=native are 4872 now available on native IBM z Systems. Specifying these options 4873 causes GCC to auto-detect the host CPU and choose the optimal 4874 setting for that system. If GCC is unable to detect the host CPU 4875 these options have no effect. 4876 * The IBM z Systems port now supports target attributes and pragmas. 4877 Please refer to the [20]documentation for details of available 4878 attributes and pragmas as well as usage instructions. 4879 * -fsplit-stack is now supported as part of the IBM z Systems port. 4880 This feature requires a recent gold linker to be used. 4881 * Support for the g5 and g6 -march=/-mtune= CPU level switches has 4882 been deprecated and will be removed in a future GCC release. -m31 4883 from now on defaults to -march=z900 if not specified otherwise. 4884 -march=native on a g5/g6 machine will default to -march=z900. 4885 4886 SH 4887 4888 * Support for SH5 / SH64 has been declared obsolete and will be 4889 removed in future releases. 4890 * Support for the FDPIC ABI has been added. It can be enabled using 4891 the new -mfdpic target option and --enable-fdpic configure option. 4892 4893 SPARC 4894 4895 * An ABI bug has been fixed in 64-bit mode. Unfortunately, this 4896 change will break binary compatibility with earlier releases for 4897 code it affects, but this should be pretty rare in practice. The 4898 conditions are: a 16-byte structure containing a double or a 8-byte 4899 vector in the second half is passed to a subprogram in slot #15, 4900 for example as 16th parameter if the first 15 ones have at most 8 4901 bytes. The double or vector was wrongly passed in floating-point 4902 register %d32 in lieu of on the stack as per the SPARC calling 4903 conventions. 4904 4905 Operating Systems 4906 4907 AIX 4908 4909 * DWARF debugging support for AIX 7.1 has been enabled as an optional 4910 debugging format. A more recent Technology Level (TL) and GCC built 4911 with that level are required for full exploitation of DWARF 4912 debugging capabilities. 4913 4914 Linux 4915 4916 * Support for the [21]musl C library was added for the AArch64, ARM, 4917 MicroBlaze, MIPS, MIPS64, PowerPC, PowerPC64, SH, i386, x32 and 4918 x86_64 targets. It can be selected using the new -mmusl option in 4919 case musl is not the default libc. GCC defaults to musl libc if it 4920 is built with a target triplet matching the *-linux-musl* pattern. 4921 4922 RTEMS 4923 4924 * The RTEMS thread model implementation changed. Mutexes now use 4925 self-contained objects defined in Newlib <sys/lock.h> instead of 4926 Classic API semaphores. The keys for thread specific data and the 4927 once function are directly defined via <pthread.h>. Self-contained 4928 condition variables are provided via Newlib <sys/lock.h>. The RTEMS 4929 thread model also supports C++11 threads. 4930 * OpenMP support now uses self-contained objects provided by Newlib 4931 <sys/lock.h> and offers a significantly better performance compared 4932 to the POSIX configuration of libgomp. It is possible to configure 4933 thread pools for each scheduler instance via the environment 4934 variable GOMP_RTEMS_THREAD_POOLS. 4935 4936 Solaris 4937 4938 * Solaris 12 is now fully supported. Minimal support had already been 4939 present in GCC 5.3. 4940 * Solaris 12 provides a full set of startup files (crt1.o, crti.o, 4941 crtn.o), which GCC now prefers over its own ones. 4942 * Position independent executables (PIE) are now supported on Solaris 4943 12. 4944 * Constructor priority is now supported on Solaris 12 with the system 4945 linker. 4946 * libvtv has been ported to Solaris 11 and up. 4947 4948 Windows 4949 4950 * The option -mstackrealign is now automatically activated in 32-bit 4951 mode whenever the use of SSE instructions is requested. 4952 4953 Other significant improvements 4954 4955 * The gcc and g++ driver programs will now provide suggestions for 4956 misspelled command-line options. 4957 4958 $ gcc -static-libfortran test.f95 4959 gcc: error: unrecognized command line option '-static-libfortran'; did you mean 4960 '-static-libgfortran'? 4961 4962 * The --enable-default-pie configure option enables generation of PIE 4963 by default. 4964 4965 GCC 6.2 4966 4967 This is the [22]list of problem reports (PRs) from GCC's bug tracking 4968 system that are known to be fixed in the 6.2 release. This list might 4969 not be complete (that is, it is possible that some PRs that have been 4970 fixed are not listed here). 4971 4972 Target Specific Changes 4973 4974 SPARC 4975 4976 * Support for --with-cpu-32 and --with-cpu-64 configure options has 4977 been added on bi-architecture platforms. 4978 * Support for the SPARC M7 (Niagara 7) processor has been added. 4979 * Support for the VIS 4.0 instruction set has been added. 4980 4981 GCC 6.3 4982 4983 This is the [23]list of problem reports (PRs) from GCC's bug tracking 4984 system that are known to be fixed in the 6.3 release. This list might 4985 not be complete (that is, it is possible that some PRs that have been 4986 fixed are not listed here). 4987 4988 Target Specific Changes 4989 4990 IA-32/x86-64 4991 4992 * Support for the [24]deprecated pcommit instruction has been 4993 removed. 4994 4995 GCC 6.4 4996 4997 This is the [25]list of problem reports (PRs) from GCC's bug tracking 4998 system that are known to be fixed in the 6.4 release. This list might 4999 not be complete (that is, it is possible that some PRs that have been 5000 fixed are not listed here). 5001 5002 Operating Systems 5003 5004 RTEMS 5005 5006 * The ABI changes on ARM so that no short enums are used by default. 5007 5008 GCC 6.5 5009 5010 This is the [26]list of problem reports (PRs) from GCC's bug tracking 5011 system that are known to be fixed in the 6.5 release. This list might 5012 not be complete (that is, it is possible that some PRs that have been 5013 fixed are not listed here). 5014 5015 5016 For questions related to the use of GCC, please consult these web 5017 pages and the [27]GCC manuals. If that fails, the 5018 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 5019 web pages and the development of GCC are welcome on our developer 5020 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 5021 archives. 5022 5023 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 5024 distribution of this entire article is permitted in any medium, 5025 provided this notice is preserved. 5026 5027 These pages are [32]maintained by the GCC team. Last modified 5028 2020-08-01[33]. 5029 5030 References 5031 5032 1. http://gcc.gnu.org/gcc-6/porting_to.html 5033 2. http://gcc.gnu.org/onlinedocs/index.html#current 5034 3. https://gcc.gnu.org/ml/gcc/2015-08/msg00101.html 5035 4. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71151 5036 5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87822 5037 6. https://www.openacc.org/ 5038 7. https://gcc.gnu.org/wiki/OpenACC 5039 8. https://gcc.gnu.org/wiki/Offloading 5040 9. https://www.openmp.org/specifications/ 5041 10. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1266 5042 11. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4377.pdf 5043 12. https://gcc.gnu.org/projects/cxx-status.html#cxx1z 5044 13. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/performance.html 5045 14. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/functions.html#gcc_jit_block_end_with_switch 5046 15. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_set_bool_allow_unreachable_blocks 5047 16. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_add_command_line_option 5048 17. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/AArch64-Function-Attributes.html#AArch64-Function-Attributes 5049 18. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/ARM-Function-Attributes.html#ARM-Function-Attributes 5050 19. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Named-Address-Spaces.html#Named-Address-Spaces 5051 20. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/S_002f390-Function-Attributes.html#S_002f390-Function-Attributes 5052 21. http://www.musl-libc.org/ 5053 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.2 5054 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.3 5055 24. https://software.intel.com/content/www/us/en/develop/blogs/deprecate-pcommit-instruction.html 5056 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.4 5057 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.5 5058 27. https://gcc.gnu.org/onlinedocs/ 5059 28. mailto:gcc-help (a] gcc.gnu.org 5060 29. mailto:gcc (a] gcc.gnu.org 5061 30. https://gcc.gnu.org/lists.html 5062 31. https://www.fsf.org/ 5063 32. https://gcc.gnu.org/about.html 5064 33. http://validator.w3.org/check/referer 5065 ====================================================================== 5066 http://gcc.gnu.org/gcc-5/index.html 5067 5068 GCC 5 Release Series 5069 5070 (This release series is no longer supported.) 5071 5072 October 10, 2017 5073 5074 The [1]GNU project and the GCC developers are pleased to announce the 5075 release of GCC 5.5. 5076 5077 This release is a bug-fix release, containing fixes for regressions in 5078 GCC 5.4 relative to previous releases of GCC. 5079 5080 Release History 5081 5082 GCC 5.5 5083 October 10, 2017 ([2]changes, [3]documentation) 5084 5085 GCC 5.4 5086 June 3, 2016 ([4]changes, [5]documentation) 5087 5088 GCC 5.3 5089 December 4, 2015 ([6]changes, [7]documentation) 5090 5091 GCC 5.2 5092 July 16, 2015 ([8]changes, [9]documentation) 5093 5094 GCC 5.1 5095 April 22, 2015 ([10]changes, [11]documentation) 5096 5097 References and Acknowledgements 5098 5099 GCC used to stand for the GNU C Compiler, but since the compiler 5100 supports several other languages aside from C, it now stands for the 5101 GNU Compiler Collection. 5102 5103 A list of [12]successful builds is updated as new information becomes 5104 available. 5105 5106 The GCC developers would like to thank the numerous people that have 5107 contributed new features, improvements, bug fixes, and other changes as 5108 well as test results to GCC. This [13]amazing group of volunteers is 5109 what makes GCC successful. 5110 5111 For additional information about GCC please refer to the [14]GCC 5112 project web site or contact the [15]GCC development mailing list. 5113 5114 To obtain GCC please use [16]our mirror sites or [17]our version 5115 control system. 5116 5117 5118 For questions related to the use of GCC, please consult these web 5119 pages and the [18]GCC manuals. If that fails, the 5120 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 5121 web pages and the development of GCC are welcome on our developer 5122 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 5123 archives. 5124 5125 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 5126 distribution of this entire article is permitted in any medium, 5127 provided this notice is preserved. 5128 5129 These pages are [23]maintained by the GCC team. Last modified 5130 2020-01-14[24]. 5131 5132 References 5133 5134 1. http://www.gnu.org/ 5135 2. http://gcc.gnu.org/gcc-5/changes.html 5136 3. http://gcc.gnu.org/onlinedocs/5.5.0/ 5137 4. http://gcc.gnu.org/gcc-5/changes.html 5138 5. http://gcc.gnu.org/onlinedocs/5.4.0/ 5139 6. http://gcc.gnu.org/gcc-5/changes.html 5140 7. http://gcc.gnu.org/onlinedocs/5.3.0/ 5141 8. http://gcc.gnu.org/gcc-5/changes.html 5142 9. http://gcc.gnu.org/onlinedocs/5.2.0/ 5143 10. http://gcc.gnu.org/gcc-5/changes.html 5144 11. http://gcc.gnu.org/onlinedocs/5.1.0/ 5145 12. http://gcc.gnu.org/gcc-5/buildstat.html 5146 13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html 5147 14. http://gcc.gnu.org/index.html 5148 15. mailto:gcc (a] gcc.gnu.org 5149 16. http://gcc.gnu.org/mirrors.html 5150 17. http://gcc.gnu.org/git.html 5151 18. https://gcc.gnu.org/onlinedocs/ 5152 19. mailto:gcc-help (a] gcc.gnu.org 5153 20. mailto:gcc (a] gcc.gnu.org 5154 21. https://gcc.gnu.org/lists.html 5155 22. https://www.fsf.org/ 5156 23. https://gcc.gnu.org/about.html 5157 24. http://validator.w3.org/check/referer 5158 ====================================================================== 5159 http://gcc.gnu.org/gcc-5/changes.html 5160 5161 GCC 5 Release Series 5162 Changes, New Features, and Fixes 5163 5164 Caveats 5165 5166 * The default mode for C is now -std=gnu11 instead of -std=gnu89. 5167 * The C++ runtime library (libstdc++) uses a new ABI by default (see 5168 [1]below). 5169 * The Graphite framework for loop optimizations no longer requires 5170 the CLooG library, only ISL version 0.14 (recommended) or 0.12.2. 5171 The installation manual contains more information about 5172 requirements to build GCC. 5173 * The non-standard C++0x type traits has_trivial_default_constructor, 5174 has_trivial_copy_constructor and has_trivial_copy_assign have been 5175 deprecated and will be removed in a future version. The standard 5176 C++11 traits is_trivially_default_constructible, 5177 is_trivially_copy_constructible and is_trivially_copy_assignable 5178 should be used instead. 5179 * On AVR, support has been added for the devices 5180 ATtiny4/5/9/10/20/40. This requires Binutils 2.25 or newer. 5181 * The AVR port uses a new scheme to describe supported devices: For 5182 each supported device the compiler provides a device-specific 5183 [2]spec file. If the compiler is used together with AVR-LibC, this 5184 requires at least GCC 5.2 and a version of AVR-LibC which 5185 implements [3]feature #44574. 5186 5187 General Optimizer Improvements 5188 5189 * Inter-procedural optimization improvements: 5190 + An Identical Code Folding (ICF) pass (controlled via 5191 -fipa-icf) has been added. Compared to the identical code 5192 folding performed by the Gold linker this pass does not 5193 require function sections. It also performs merging before 5194 inlining, so inter-procedural optimizations are aware of the 5195 code re-use. On the other hand not all unifications performed 5196 by a linker are doable by GCC which must honor aliasing 5197 information. During link-time optimization of Firefox, this 5198 pass unifies about 31000 functions, that is 14% overall. 5199 + The devirtualization pass was significantly improved by adding 5200 better support for speculative devirtualization and dynamic 5201 type detection. About 50% of virtual calls in Firefox are now 5202 speculatively devirtualized during link-time optimization. 5203 + A new comdat localization pass allows the linker to eliminate 5204 more dead code in presence of C++ inline functions. 5205 + Virtual tables are now optimized. Local aliases are used to 5206 reduce dynamic linking time of C++ virtual tables on ELF 5207 targets and data alignment has been reduced to limit data 5208 segment bloat. 5209 + A new -fno-semantic-interposition option can be used to 5210 improve code quality of shared libraries where interposition 5211 of exported symbols is not allowed. 5212 + Write-only variables are now detected and optimized out. 5213 + With profile feedback the function inliner can now bypass 5214 --param inline-insns-auto and --param inline-insns-single 5215 limits for hot calls. 5216 + The IPA reference pass was significantly sped up making it 5217 feasible to enable -fipa-reference with -fprofile-generate. 5218 This also solves a bottleneck seen when building Chromium with 5219 link-time optimization. 5220 + The symbol table and call-graph API was reworked to C++ and 5221 simplified. 5222 + The interprocedural propagation of constants now also 5223 propagates alignments of pointer parameters. This for example 5224 means that the vectorizer often does not need to generate loop 5225 prologues and epilogues to make up for potential 5226 misalignments. 5227 * Link-time optimization improvements: 5228 + One Definition Rule based merging of C++ types has been 5229 implemented. Type merging enables better devirtualization and 5230 alias analysis. Streaming extra information needed to merge 5231 types adds about 2-6% of memory size and object size increase. 5232 This can be controlled by -flto-odr-type-merging. 5233 + Command-line optimization and target options are now streamed 5234 on a per-function basis and honored by the link-time 5235 optimizer. This change makes link-time optimization a more 5236 transparent replacement of per-file optimizations. It is now 5237 possible to build projects that require different optimization 5238 settings for different translation units (such as -ffast-math, 5239 -mavx, or -finline). Contrary to earlier GCC releases, the 5240 optimization and target options passed on the link command 5241 line are ignored. 5242 Note that this applies only to those command-line options that 5243 can be passed to optimize and target attributes. Command-line 5244 options affecting global code generation (such as -fpic), 5245 warnings (such as -Wodr), optimizations affecting the way 5246 static variables are optimized (such as -fcommon), debug 5247 output (such as -g), and --param parameters can be applied 5248 only to the whole link-time optimization unit. In these cases, 5249 it is recommended to consistently use the same options at both 5250 compile time and link time. 5251 + GCC bootstrap now uses slim LTO object files. 5252 + Memory usage and link times were improved. Tree merging was 5253 sped up, memory usage of GIMPLE declarations and types was 5254 reduced, and, support for on-demand streaming of variable 5255 constructors was added. 5256 * Feedback directed optimization improvements: 5257 + A new auto-FDO mode uses profiles collected by low overhead 5258 profiling tools (perf) instead of more expensive program 5259 instrumentation (via -fprofile-generate). SPEC2006 benchmarks 5260 on x86-64 improve by 4.7% with auto-FDO and by 7.3% with 5261 traditional feedback directed optimization. 5262 + Profile precision was improved in presence of C++ inline and 5263 extern inline functions. 5264 + The new gcov-tool utility allows manipulating profiles. 5265 + Profiles are now more tolerant to source file changes (this 5266 can be controlled by --param profile-func-internal-id). 5267 * Register allocation improvements: 5268 + A new local register allocator (LRA) sub-pass, controlled by 5269 -flra-remat, implements control-flow sensitive global register 5270 rematerialization. Instead of spilling and restoring a 5271 register value, it is recalculated if it is profitable. The 5272 sub-pass improved SPEC2000 generated code by 1% and 0.5% 5273 correspondingly on ARM and x86-64. 5274 + Reuse of the PIC hard register, instead of using a fixed 5275 register, was implemented on x86/x86-64 targets. This improves 5276 generated PIC code performance as more hard registers can be 5277 used. Shared libraries can significantly benefit from this 5278 optimization. Currently it is switched on only for x86/x86-64 5279 targets. As RA infrastructure is already implemented for PIC 5280 register reuse, other targets might follow this in the future. 5281 + A simple form of inter-procedural RA was implemented. When it 5282 is known that a called function does not use caller-saved 5283 registers, save/restore code is not generated around the call 5284 for such registers. This optimization can be controlled by 5285 -fipa-ra 5286 + LRA is now much more effective at generating spills of general 5287 registers into vector registers instead of memory on 5288 architectures (e.g., modern Intel processors) where this is 5289 profitable. 5290 * UndefinedBehaviorSanitizer gained a few new sanitization options: 5291 + -fsanitize=float-divide-by-zero: detect floating-point 5292 division by zero; 5293 + -fsanitize=float-cast-overflow: check that the result of 5294 floating-point type to integer conversions do not overflow; 5295 + -fsanitize=bounds: enable instrumentation of array bounds and 5296 detect out-of-bounds accesses; 5297 + -fsanitize=alignment: enable alignment checking, detect 5298 various misaligned objects; 5299 + -fsanitize=object-size: enable object size checking, detect 5300 various out-of-bounds accesses. 5301 + -fsanitize=vptr: enable checking of C++ member function calls, 5302 member accesses and some conversions between pointers to base 5303 and derived classes, detect if the referenced object does not 5304 have the correct dynamic type. 5305 * Pointer Bounds Checker, a bounds violation detector, has been added 5306 and can be enabled via -fcheck-pointer-bounds. Memory accesses are 5307 instrumented with run-time checks of used pointers against their 5308 bounds to detect pointer bounds violations (overflows). The Pointer 5309 Bounds Checker is available on x86/x86-64 GNU/Linux targets with a 5310 new ISA extension Intel MPX support. See the Pointer Bounds Checker 5311 [4]Wiki page for more details. 5312 5313 New Languages and Language specific improvements 5314 5315 * [5]OpenMP 4.0 specification offloading features are now supported 5316 by the C, C++, and Fortran compilers. Generic changes: 5317 + Infrastructure (suitable for any vendor). 5318 + Testsuite which covers offloading from the [6]OpenMP 4.0 5319 Examples document. 5320 Specific for upcoming Intel Xeon Phi products: 5321 + Run-time library. 5322 + Card emulator. 5323 * GCC 5 includes a preliminary implementation of the OpenACC 2.0a 5324 specification. OpenACC is intended for programming accelerator 5325 devices such as GPUs. See [7]the OpenACC wiki page for more 5326 information. 5327 5328 C family 5329 5330 * The default setting of the -fdiagnostics-color= command-line option 5331 is now [8]configurable when building GCC using configuration option 5332 --with-diagnostics-color=. The possible values are: never, always, 5333 auto and auto-if-env. The new default auto uses color only when the 5334 standard error is a terminal. The default in GCC 4.9 was 5335 auto-if-env, which is equivalent to auto if there is a non-empty 5336 GCC_COLORS environment variable, and never otherwise. As in GCC 5337 4.9, an empty GCC_COLORS variable in the environment will always 5338 disable colors, no matter what the default is or what command-line 5339 options are used. 5340 * A new command-line option -Wswitch-bool has been added for the C 5341 and C++ compilers, which warns whenever a switch statement has an 5342 index of boolean type. 5343 * A new command-line option -Wlogical-not-parentheses has been added 5344 for the C and C++ compilers, which warns about "logical not" used 5345 on the left hand side operand of a comparison. 5346 * A new command-line option -Wsizeof-array-argument has been added 5347 for the C and C++ compilers, which warns when the sizeof operator 5348 is applied to a parameter that has been declared as an array in a 5349 function definition. 5350 * A new command-line option -Wbool-compare has been added for the C 5351 and C++ compilers, which warns about boolean expressions compared 5352 with an integer value different from true/false. 5353 * Full support for [9]Cilk Plus has been added to the GCC compiler. 5354 Cilk Plus is an extension to the C and C++ languages to support 5355 data and task parallelism. 5356 * A new attribute no_reorder prevents reordering of selected symbols 5357 against other such symbols or inline assembler. This enables to 5358 link-time optimize the Linux kernel without having to resort to 5359 -fno-toplevel-reorder that disables several optimizations. 5360 * New preprocessor constructs, __has_include and __has_include_next, 5361 to test the availability of headers have been added. 5362 This demonstrates a way to include the header <optional> only if it 5363 is available: 5364 5365 #ifdef __has_include 5366 # if __has_include(<optional>) 5367 # include <optional> 5368 # define have_optional 1 5369 # elif __has_include(<experimental/optional>) 5370 # include <experimental/optional> 5371 # define have_optional 1 5372 # define experimental_optional 5373 # else 5374 # define have_optional 0 5375 # endif 5376 #endif 5377 5378 The header search paths for __has_include and __has_include_next 5379 are equivalent to those of the standard directive #include and the 5380 extension #include_next respectively. 5381 * A new built-in function-like macro to determine the existence of an 5382 attribute, __has_attribute, has been added. The equivalent built-in 5383 macro __has_cpp_attribute was added to C++ to support 5384 [10]Feature-testing recommendations for C++. The macro 5385 __has_attribute is added to all C-like languages as an extension: 5386 5387 int 5388 #ifdef __has_attribute 5389 # if __has_attribute(__noinline__) 5390 __attribute__((__noinline__)) 5391 # endif 5392 #endif 5393 foo(int x); 5394 5395 If an attribute exists, a nonzero constant integer is returned. For 5396 standardized C++ attributes a date is returned, otherwise the 5397 constant returned is 1. Both __has_attribute and 5398 __has_cpp_attribute will add underscores to an attribute name if 5399 necessary to resolve the name. For C++11 and onwards the attribute 5400 may be scoped. 5401 * A new set of built-in functions for arithmetics with overflow 5402 checking has been added: __builtin_add_overflow, 5403 __builtin_sub_overflow and __builtin_mul_overflow and for 5404 compatibility with clang also other variants. These builtins have 5405 two integral arguments (which don't need to have the same type), 5406 the arguments are extended to infinite precision signed type, +, - 5407 or * is performed on those, and the result is stored in an integer 5408 variable pointed to by the last argument. If the stored value is 5409 equal to the infinite precision result, the built-in functions 5410 return false, otherwise true. The type of the integer variable that 5411 will hold the result can be different from the types of the first 5412 two arguments. The following snippet demonstrates how this can be 5413 used in computing the size for the calloc function: 5414 5415 void * 5416 calloc (size_t x, size_t y) 5417 { 5418 size_t sz; 5419 if (__builtin_mul_overflow (x, y, &sz)) 5420 return NULL; 5421 void *ret = malloc (sz); 5422 if (ret) memset (res, 0, sz); 5423 return ret; 5424 } 5425 5426 On e.g. i?86 or x86-64 the above will result in a mul instruction 5427 followed by a jump on overflow. 5428 * The option -fextended-identifiers is now enabled by default for 5429 C++, and for C99 and later C versions. Various bugs in the 5430 implementation of extended identifiers have been fixed. 5431 5432 C 5433 5434 * The default mode has been changed to -std=gnu11. 5435 * A new command-line option -Wc90-c99-compat has been added to warn 5436 about features not present in ISO C90, but present in ISO C99. 5437 * A new command-line option -Wc99-c11-compat has been added to warn 5438 about features not present in ISO C99, but present in ISO C11. 5439 * It is possible to disable warnings about conversions between 5440 pointers that have incompatible types via a new warning option 5441 -Wno-incompatible-pointer-types; warnings about implicit 5442 incompatible integer to pointer and pointer to integer conversions 5443 via a new warning option -Wno-int-conversion; and warnings about 5444 qualifiers on pointers being discarded via a new warning option 5445 -Wno-discarded-qualifiers. 5446 * To allow proper use of const qualifiers with multidimensional 5447 arrays, GCC will not warn about incompatible pointer types anymore 5448 for conversions between pointers to arrays with and without const 5449 qualifier (except when using -pedantic). Instead, a new warning is 5450 emitted only if the const qualifier is lost. This can be controlled 5451 with a new warning option -Wno-discarded-array-qualifiers. 5452 * The C front end now generates more precise caret diagnostics. 5453 * The -pg command-line option now only affects the current file in an 5454 LTO build. 5455 5456 C++ 5457 5458 * G++ now supports [11]C++14 variable templates. 5459 * -Wnon-virtual-dtor doesn't warn anymore for final classes. 5460 * Excessive template instantiation depth is now a fatal error. This 5461 prevents excessive diagnostics that usually do not help to identify 5462 the problem. 5463 * G++ and libstdc++ now implement the feature-testing macros from 5464 [12]Feature-testing recommendations for C++. 5465 * G++ now allows typename in a template template parameter. 5466 5467 template<template<typename> typename X> struct D; // OK 5468 5469 * G++ now supports [13]C++14 aggregates with non-static data member 5470 initializers. 5471 5472 struct A { int i, j = i; }; 5473 A a = { 42 }; // a.j is also 42 5474 5475 * G++ now supports [14]C++14 extended constexpr. 5476 5477 constexpr int f (int i) 5478 { 5479 int j = 0; 5480 for (; i > 0; --i) 5481 ++j; 5482 return j; 5483 } 5484 5485 constexpr int i = f(42); // i is 42 5486 5487 * G++ now supports the [15]C++14 sized deallocation functions. 5488 5489 void operator delete (void *, std::size_t) noexcept; 5490 void operator delete[] (void *, std::size_t) noexcept; 5491 5492 * A new One Definition Rule violation warning (controlled by -Wodr) 5493 detects mismatches in type definitions and virtual table contents 5494 during link-time optimization. 5495 * New warnings -Wsuggest-final-types and -Wsuggest-final-methods help 5496 developers to annotate programs with final specifiers (or anonymous 5497 namespaces) to improve code generation. These warnings can be used 5498 at compile time, but they are more useful in combination with 5499 link-time optimization. 5500 * G++ no longer supports [16]N3639 variable length arrays, as they 5501 were removed from the C++14 working paper prior to ratification. 5502 GNU VLAs are still supported, so VLA support is now the same in 5503 C++14 mode as in C++98 and C++11 modes. 5504 * G++ now allows passing a non-trivially-copyable class via C 5505 varargs, which is conditionally-supported with 5506 implementation-defined semantics in the standard. This uses the 5507 same calling convention as a normal value parameter. 5508 * G++ now defaults to -fabi-version=9 and -fabi-compat-version=2. So 5509 various mangling bugs are fixed, but G++ will still emit aliases 5510 with the old, wrong mangling where feasible. -Wabi=2 will warn 5511 about differences between ABI version 2 and the current setting. 5512 * G++ 5.2 fixes the alignment of std::nullptr_t. Most code is likely 5513 to be unaffected, but -Wabi=8 will warn about a non-static data 5514 member with type std::nullptr_t which changes position due to this 5515 change. 5516 5517 Runtime Library (libstdc++) 5518 5519 * A [17]Dual ABI is provided by the library. A new ABI is enabled by 5520 default. The old ABI is still supported and can be used by defining 5521 the macro _GLIBCXX_USE_CXX11_ABI to 0 before including any C++ 5522 standard library headers. 5523 * A new implementation of std::string is enabled by default, using 5524 the small string optimization instead of copy-on-write reference 5525 counting. 5526 * A new implementation of std::list is enabled by default, with an 5527 O(1) size() function; 5528 * [18]Full support for C++11, including the following new features: 5529 + std::deque and std::vector<bool> meet the allocator-aware 5530 container requirements; 5531 + movable and swappable iostream classes; 5532 + support for std::align and std::aligned_union; 5533 + type traits std::is_trivially_copyable, 5534 std::is_trivially_constructible, std::is_trivially_assignable 5535 etc.; 5536 + I/O manipulators std::put_time, std::get_time, std::hexfloat 5537 and std::defaultfloat; 5538 + generic locale-aware std::isblank; 5539 + locale facets for Unicode conversion; 5540 + atomic operations for std::shared_ptr; 5541 + std::notify_all_at_thread_exit() and functions for making 5542 futures ready at thread exit. 5543 * Support for the C++11 hexfloat manipulator changes how the num_put 5544 facet formats floating point types when 5545 ios_base::fixed|ios_base::scientific is set in a stream's fmtflags. 5546 This change affects all language modes, even though the C++98 5547 standard gave no special meaning to that combination of flags. To 5548 prevent the use of hexadecimal notation for floating point types 5549 use str.unsetf(std::ios_base::floatfield) to clear the relevant 5550 bits in str.flags(). 5551 * [19]Full experimental support for C++14, including the following 5552 new features: 5553 + std::is_final type trait; 5554 + heterogeneous comparison lookup in associative containers. 5555 + global functions cbegin, cend, rbegin, rend, crbegin, and 5556 crend for range access to containers, arrays and initializer 5557 lists. 5558 * [20]Improved experimental support for the Library Fundamentals TS, 5559 including: 5560 + class std::experimental::any; 5561 + function template std::experimental::apply; 5562 + function template std::experimental::sample; 5563 + function template std::experimental::search and related 5564 searcher types; 5565 + variable templates for type traits; 5566 + function template std::experimental::not_fn. 5567 * New random number distributions logistic_distribution and 5568 uniform_on_sphere_distribution as extensions. 5569 * [21]GDB Xmethods for containers and std::unique_ptr. 5570 5571 Fortran 5572 5573 * Compatibility notice: 5574 + The version of the module files (.mod) has been incremented. 5575 + For free-form source files [22]-Werror=line-truncation is now 5576 enabled by default. Note that comments exceeding the line 5577 length are not diagnosed. (For fixed-form source code, the 5578 same warning is available but turned off by default, such that 5579 excess characters are ignored. -ffree-line-length-n and 5580 -ffixed-line-length-n can be used to modify the default line 5581 lengths of 132 and 72 columns, respectively.) 5582 + The -Wtabs option is now more sensible: with -Wtabs the 5583 compiler warns if it encounters tabs and with -Wno-tabs this 5584 warning is turned off. Before, -Wno-tabs warned and -Wtabs 5585 disabled the warning. As before, this warning is also enabled 5586 by -Wall, -pedantic and the f95, f2003, f2008 and f2008ts 5587 options of -std=. 5588 * Incomplete support for colorizing diagnostics emitted by gfortran 5589 has been added. The option [23]-fdiagnostics-color controls when 5590 color is used in diagnostics. The default value of this option can 5591 be [24]configured when building GCC. The GCC_COLORS environment 5592 variable can be used to customize the colors or disable coloring 5593 completely. Sample diagnostics output: 5594 $ gfortran -fdiagnostics-color=always -Wuse-without-only test.f90 5595 test.f90:6:1: 5596 5597 0 continue 5598 1 5599 Error: Zero is not a valid statement label at (1) 5600 test.f90:9:6: 5601 5602 USE foo 5603 1 5604 Warning: USE statement at (1) has no ONLY qualifier [-Wuse-without-only] 5605 5606 * The -Wuse-without-only option has been added to warn when a USE 5607 statement has no ONLY qualifier and thus implicitly imports all 5608 public entities of the used module. 5609 * Formatted READ and WRITE statements now work correctly in 5610 locale-aware programs. For more information and potential caveats, 5611 see [25]Section 5.3 Thread-safety of the runtime library in the 5612 manual. 5613 * [26]Fortran 2003: 5614 + The intrinsic IEEE modules (IEEE_FEATURES, IEEE_EXCEPTIONS and 5615 IEEE_ARITHMETIC) are now supported. 5616 * [27]Fortran 2008: 5617 + [28]Coarrays: Full experimental support of Fortran 2008's 5618 coarrays with -fcoarray=lib except for allocatable/pointer 5619 components of derived-type coarrays. GCC currently only ships 5620 with a single-image library (libcaf_single), but multi-image 5621 support based on MPI and GASNet is provided by the libraries 5622 of the [29]OpenCoarrays project. 5623 * TS18508 Additional Parallel Features in Fortran: 5624 + Support for the collective intrinsic subroutines CO_MAX, 5625 CO_MIN, CO_SUM, CO_BROADCAST and CO_REDUCE has been added, 5626 including -fcoarray=lib support. 5627 + Support for the new atomic intrinsics has been added, 5628 including -fcoarray=lib support. 5629 * Fortran 2015: 5630 + Support for IMPLICIT NONE (external, type). 5631 + ERROR STOP is now permitted in pure procedures. 5632 5633 Go 5634 5635 * GCC 5 provides a complete implementation of the Go 1.4.2 release. 5636 * Building GCC 5 with Go enabled will install two new programs: 5637 [30]go and [31]gofmt. 5638 5639 libgccjit 5640 5641 New in GCC 5 is the ability to build GCC as a shared library for 5642 embedding in other processes (such as interpreters), suitable for 5643 Just-In-Time compilation to machine code. 5644 5645 The shared library has a [32]C API and a [33]C++ wrapper API providing 5646 some "syntactic sugar". There are also bindings available from 3rd 5647 parties for [34]Python and for [35]D. 5648 5649 For example, this library can be used by interpreters for [36]compiling 5650 functions from bytecode to machine code. 5651 5652 The library can also be used for ahead-of-time compilation, enabling 5653 GCC to be plugged into a pre-existing front end. An example of using 5654 this to build a compiler for an esoteric language we'll refer to as 5655 "brainf" can be seen [37]here. 5656 5657 libgccjit is licensed under the GPLv3 (or at your option, any later 5658 version) 5659 5660 It should be regarded as experimental at this time. 5661 5662 New Targets and Target Specific Improvements 5663 5664 Reporting stack usage 5665 5666 * The BFIN, FT32, H8300, IQ2000 and M32C targets now support the 5667 -fstack-usage option. 5668 5669 AArch64 5670 5671 * Code generation for the ARM Cortex-A57 processor has been improved. 5672 A more accurate instruction scheduling model for the processor is 5673 now used, and a number of compiler tuning parameters have been set 5674 to offer increased performance when compiling with -mcpu=cortex-a57 5675 or -mtune=cortex-a57. 5676 * A workaround for the ARM Cortex-A53 erratum 835769 has been added 5677 and can be enabled by giving the -mfix-cortex-a53-835769 option. 5678 Alternatively it can be enabled by default by configuring GCC with 5679 the --enable-fix-cortex-a53-835769 option. 5680 * The optional cryptographic extensions to the ARMv8-A architecture 5681 are no longer enabled by default when specifying the 5682 -mcpu=cortex-a53, -mcpu=cortex-a57 or -mcpu=cortex-a57.cortex-a53 5683 options. To enable these extensions add +crypto to the value of 5684 -mcpu or -march e.g. -mcpu=cortex-a53+crypto. 5685 * Support has been added for the following processors (GCC 5686 identifiers in parentheses): ARM Cortex-A72 (cortex-a72) and 5687 initial support for its big.LITTLE combination with the ARM 5688 Cortex-A53 (cortex-a72.cortex-a53), Cavium ThunderX (thunderx), 5689 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 5690 The GCC identifiers can be used as arguments to the -mcpu or -mtune 5691 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 5692 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 5693 support for the Cortex-A72. 5694 * The transitional options -mlra and -mno-lra have been removed. The 5695 AArch64 backend now uses the local register allocator (LRA) only. 5696 5697 ARM 5698 5699 * Thumb-1 assembly code is now generated in unified syntax. The new 5700 option -masm-syntax-unified specifies whether inline assembly code 5701 is using unified syntax. By default the option is off which means 5702 non-unified syntax is used. However this is subject to change in 5703 future releases. Eventually the non-unified syntax will be 5704 deprecated. 5705 * It is now a configure-time error to use the --with-cpu configure 5706 option with either of --with-tune or --with-arch. 5707 * Code generation for the ARM Cortex-A57 processor has been improved. 5708 A more accurate instruction scheduling model for the processor is 5709 now used, and a number of compiler tuning parameters have been set 5710 to offer increased performance when compiling with -mcpu=cortex-a57 5711 or -mtune=cortex-a57. 5712 * Support has been added for the following processors (GCC 5713 identifiers in parentheses): ARM Cortex-A17 (cortex-a17) and 5714 initial support for its big.LITTLE combination with the ARM 5715 Cortex-A7 (cortex-a17.cortex-a7), ARM Cortex-A72 (cortex-a72) and 5716 initial support for its big.LITTLE combination with the ARM 5717 Cortex-A53 (cortex-a72.cortex-a53), ARM Cortex-M7 (cortex-m7), 5718 Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1). 5719 The GCC identifiers can be used as arguments to the -mcpu or -mtune 5720 options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53. 5721 Using -mcpu=cortex-a72 requires a version of GNU binutils that has 5722 support for the Cortex-A72. 5723 * The deprecated option -mwords-little-endian has been removed. 5724 * The options -mapcs, -mapcs-frame, -mtpcs-frame and 5725 -mtpcs-leaf-frame which are only applicable to the old ABI have 5726 been deprecated. 5727 * The transitional options -mlra and -mno-lra have been removed. The 5728 ARM backend now uses the local register allocator (LRA) only. 5729 5730 AVR 5731 5732 * The compiler no more supports individual devices like ATmega8. 5733 Specifying, say, -mmcu=atmega8 triggers the usage of the 5734 device-specific [38]spec file specs-atmega8 which is part of the 5735 installation and describes options for the sub-processes like 5736 compiler proper, assembler and linker. You can add support for a 5737 new device -mmcu=mydevice as follows: 5738 1. In an empty directory /someplace, create a new directory 5739 device-specs. 5740 2. Copy a device spec file from the installed device-specs 5741 folder, follow the comments in that file and then save it as 5742 /someplace/device-specs/specs-mydevice. 5743 3. Add -B /someplace -mmcu=mydevice to the compiler's 5744 command-line options. Notice that /someplace must specify an 5745 absolute path and that mydevice must not start with "avr". 5746 4. Provided you have a device-specific library libmydevice.a 5747 available, you can put it at /someplace, dito for a 5748 device-specific startup file crtmydevice.o. 5749 The contents of the device spec files depend on the compiler's 5750 configuration, in particular on --with-avrlibc=no and whether or 5751 not it is configured for RTEMS. 5752 * A new command-line option -nodevicelib has been added. It prevents 5753 the compiler from linking against AVR-LibC's device-specific 5754 library libdevice.a. 5755 * The following three command-line options have been added: 5756 5757 -mrmw 5758 Set if the device supports the read-modify-write 5759 instructions LAC, LAS, LAT and XCH. 5760 5761 -mn-flash=size 5762 Specify the flash size of the device in units of 64 KiB, 5763 rounded up to the next integer as needed. This option 5764 affects the availability of the [39]AVR address-spaces. 5765 5766 -mskip-bug 5767 Set if the device is affected by the respective silicon 5768 bug. 5769 5770 In general, you don't need to set these options by hand. The new 5771 device-specific spec file will set them as needed. 5772 5773 IA-32/x86-64 5774 5775 * New [40]ISA extensions support AVX-512{BW,DQ,VL,IFMA,VBMI} of 5776 Intel's CPU codenamed Skylake Server was added to GCC. That 5777 includes inline assembly support, new intrinsics, and basic 5778 autovectorization. These new AVX-512 extensions are available via 5779 the following GCC switches: AVX-512 Vector Length EVEX feature: 5780 -mavx512vl, AVX-512 Byte and Word instructions: -mavx512bw, AVX-512 5781 Dword and Qword instructions: -mavx512dq, AVX-512 FMA-52 5782 instructions: -mavx512ifma and for AVX-512 Vector Bit Manipulation 5783 Instructions: -mavx512vbmi. 5784 * New ISA extensions support Intel MPX was added to GCC. This new 5785 extension is available via the -mmpx compiler switch. Intel MPX is 5786 a set of processor features which, with compiler, run-time library 5787 and OS support, brings increased robustness to software by run-time 5788 checking pointer references against their bounds. In GCC Intel MPX 5789 is supported by Pointer Bounds Checker and libmpx run-time 5790 libraries. 5791 * The new -mrecord-mcount option for -pg generates a Linux kernel 5792 style table of pointers to mcount or __fentry__ calls at the 5793 beginning of functions. The new -mnop-mcount option in addition 5794 also generates nops in place of the __fentry__ or mcount call, so 5795 that a call per function can be later patched in. This can be used 5796 for low overhead tracing or hot code patching. 5797 * The new -malign-data option controls how GCC aligns variables. 5798 -malign-data=compat uses increased alignment compatible with GCC 5799 4.8 and earlier, -malign-data=abi uses alignment as specified by 5800 the psABI, and -malign-data=cacheline uses increased alignment to 5801 match the cache line size. -malign-data=compat is the default. 5802 * The new -mskip-rax-setup option skips setting up the RAX register 5803 when SSE is disabled and there are no variable arguments passed in 5804 vector registers. This can be used to optimize the Linux kernel. 5805 5806 MIPS 5807 5808 * MIPS Releases 3 and 5 are now directly supported. Use the 5809 command-line options -mips32r3, -mips64r3, -mips32r5 and -mips64r5 5810 to enable code-generation for these processors. 5811 * The Imagination P5600 processor is now supported using the 5812 -march=p5600 command-line option. 5813 * The Cavium Octeon3 processor is now supported using the 5814 -march=octeon3 command-line option. 5815 * MIPS Release 6 is now supported using the -mips32r6 and -mips64r6 5816 command-line options. 5817 * The o32 ABI has been modified and extended. The o32 64-bit 5818 floating-point register support is now obsolete and has been 5819 removed. It has been replaced by three ABI extensions FPXX, FP64A, 5820 and FP64. The meaning of the -mfp64 command-line option has 5821 changed. It is now used to enable the FP64A and FP64 ABI 5822 extensions. 5823 + The FPXX extension requires that code generated to access 5824 double-precision values use even-numbered registers. Code that 5825 adheres to this extension is link-compatible with all other 5826 o32 double-precision ABI variants and will execute correctly 5827 in all hardware FPU modes. The command-line options -mabi=32 5828 -mfpxx can be used to enable this extension. MIPS II is the 5829 minimum processor required. 5830 + The o32 FP64A extension requires that floating-point registers 5831 be 64-bit and odd-numbered single-precision registers are not 5832 allowed. Code that adheres to the o32 FP64A variant is 5833 link-compatible with all other o32 double-precision ABI 5834 variants. The command-line options -mabi=32 -mfp64 5835 -mno-odd-spreg can be used to enable this extension. MIPS32R2 5836 is the minimum processor required. 5837 + The o32 FP64 extension also requires that floating-point 5838 registers be 64-bit, but permits the use of single-precision 5839 registers. Code that adheres to the o32 FP64 variant is 5840 link-compatible with o32 FPXX and o32 FP64A variants only, 5841 i.e. it is not compatible with the original o32 5842 double-precision ABI. The command-line options -mabi=32 -mfp64 5843 -modd-spreg can be used to enable this extension. MIPS32R2 is 5844 the minimum processor required. 5845 The new ABI variants can be enabled by default using the configure 5846 time options --with-fp-32=[32|xx|64] and --with(out)-odd-sp-reg-32. 5847 It is strongly recommended that all vendors begin to set o32 FPXX 5848 as the default ABI. This will be required to run the generated code 5849 on MIPSR5 cores in conjunction with future MIPS SIMD (MSA) code and 5850 MIPSR6 cores. 5851 * GCC will now pass all floating-point options to the assembler if 5852 GNU binutils 2.25 is used. As a result, any inline assembly code 5853 that uses hard-float instructions should be amended to include a 5854 .set directive to override the global assembler options when 5855 compiling for soft-float targets. 5856 5857 NDS32 5858 5859 * The variadic function ABI implementation is now compatible with 5860 past Andes toolchains where the caller uses registers to pass 5861 arguments and the callee is in charge of pushing them on stack. 5862 * The options -mforce-fp-as-gp, -mforbid-fp-as-gp, and -mex9 have 5863 been removed since they are not yet available in the nds32 port of 5864 GNU binutils. 5865 * A new option -mcmodel=[small|medium|large] supports varied code 5866 models on code generation. The -mgp-direct option became 5867 meaningless and can be discarded. 5868 5869 RX 5870 5871 * A new command line option -mno-allow-string-insns can be used to 5872 disable the generation of the SCMPU, SMOVU, SMOVB, SMOVF, SUNTIL, 5873 SWHILE and RMPA instructions. An erratum released by Renesas shows 5874 that it is unsafe to use these instructions on addresses within the 5875 I/O space of the processor. The new option can be used when the 5876 programmer is concerned that the I/O space might be accessed. The 5877 default is still to enable these instructions. 5878 5879 SH 5880 5881 * The compiler will now pass the appropriate --isa= option to the 5882 assembler. 5883 * The default handling for the GBR has been changed from call 5884 clobbered to call preserved. The old behavior can be reinstated by 5885 specifying the option -fcall-used-gbr. 5886 * Support for the SH4A fpchg instruction has been added which will be 5887 utilized when switching between single and double precision FPU 5888 modes. 5889 * The compiler no longer uses the __fpscr_values array for switching 5890 between single and double FPU precision modes on non-SH4A targets. 5891 Instead mode switching will now be performed by storing, modifying 5892 and reloading the FPSCR, so that other FPSCR bits are preserved 5893 across mode switches. The __fpscr_values array that is defined in 5894 libgcc is still present for backwards compatibility, but it will 5895 not be referenced by compiler generated code anymore. 5896 * New builtin functions __builtin_sh_get_fpscr and 5897 __builtin_sh_set_fpscr have been added. The __builtin_sh_set_fpscr 5898 function will mask the specified bits in such a way that the SZ, PR 5899 and FR mode bits will be preserved, while changing the other bits. 5900 These new functions do not reference the __fpscr_values array. The 5901 old functions __set_fpscr and __get_fpscr in libgcc which access 5902 the __fpscr_values array are still present for backwards 5903 compatibility, but their usage is highly discouraged. 5904 * Some improvements to code generated for __atomic built-in 5905 functions. 5906 * When compiling for SH2E the compiler will no longer force the usage 5907 of delay slots for conditional branch instructions bt and bf. The 5908 old behavior can be reinstated (e.g. to work around a hardware bug 5909 in the original SH7055) by specifying the new option 5910 -mcbranch-force-delay-slot. 5911 5912 Operating Systems 5913 5914 AIX 5915 5916 * GCC now supports stabs debugging continuation lines to allow long 5917 stabs debug information without overflow that generates AIX linker 5918 errors. 5919 5920 DragonFly BSD 5921 5922 * GCC now supports the DragonFly BSD operating system. 5923 5924 FreeBSD 5925 5926 * GCC now supports the FreeBSD operating system for the arm port 5927 through the arm*-*-freebsd* target triplets. 5928 5929 VxWorks MILS 5930 5931 * GCC now supports the MILS (Multiple Independent Levels of Security) 5932 variant of WindRiver's VxWorks operating system for PowerPC 5933 targets. 5934 5935 Other significant improvements 5936 5937 * The gcc-ar, gcc-nm, gcc-ranlib wrappers now understand a -B option 5938 to set the compiler to use. 5939 5940 * When the new command-line option -freport-bug is used, GCC 5941 automatically generates a developer-friendly reproducer whenever an 5942 internal compiler error is encountered. 5943 5944 GCC 5.2 5945 5946 This is the [41]list of problem reports (PRs) from GCC's bug tracking 5947 system that are known to be fixed in the 5.2 release. This list might 5948 not be complete (that is, it is possible that some PRs that have been 5949 fixed are not listed here). 5950 5951 Target Specific Changes 5952 5953 IA-32/x86-64 5954 5955 * Support for new AMD instructions monitorx and mwaitx has been 5956 added. This includes new intrinsic and built-in support. It is 5957 enabled through option -mmwaitx. The instructions monitorx and 5958 mwaitx implement the same functionality as the old monitor and 5959 mwait instructions. In addition mwaitx adds a configurable timer. 5960 The timer value is received as third argument and stored in 5961 register %ebx. 5962 5963 S/390, System z, IBM z Systems 5964 5965 * Support for the IBM z13 processor has been added. When using the 5966 -march=z13 option, the compiler will generate code making use of 5967 the new instructions and registers introduced with the vector 5968 extension facility. The -mtune=z13 option enables z13 specific 5969 instruction scheduling without making use of new instructions. 5970 Compiling code with -march=z13 reduces the default alignment of 5971 vector types bigger than 8 bytes to 8. This is an ABI change and 5972 care must be taken when linking modules compiled with different 5973 arch levels which interchange variables containing vector type 5974 values. For newly compiled code the GNU linker will emit a warning. 5975 * The -mzvector option enables a C/C++ language extension. This 5976 extension provides a new keyword vector which can be used to define 5977 vector type variables. (Note: This is not available when enforcing 5978 strict standard compliance e.g. with -std=c99. Either enable GNU 5979 extensions with e.g. -std=gnu99 or use __vector instead of vector.) 5980 Additionally a set of overloaded builtins is provided which is 5981 partially compatible to the PowerPC Altivec builtins. In order to 5982 make use of these builtins the vecintrin.h header file needs to be 5983 included. 5984 5985 GCC 5.3 5986 5987 This is the [42]list of problem reports (PRs) from GCC's bug tracking 5988 system that are known to be fixed in the 5.3 release. This list might 5989 not be complete (that is, it is possible that some PRs that have been 5990 fixed are not listed here). 5991 5992 Target Specific Changes 5993 5994 IA-32/x86-64 5995 5996 * GCC now supports the Intel CPU named Skylake with AVX-512 5997 extensions through -march=skylake-avx512. The switch enables the 5998 following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW, 5999 AVX-512DQ. 6000 6001 S/390, System z, IBM z Systems 6002 6003 * With this version of GCC IBM z Systems support has been added to 6004 the GO runtime environment. GCC 5.3 has proven to be able to 6005 compile larger GO applications on IBM z Systems. 6006 6007 GCC 5.4 6008 6009 This is the [43]list of problem reports (PRs) from GCC's bug tracking 6010 system that are known to be fixed in the 5.4 release. This list might 6011 not be complete (that is, it is possible that some PRs that have been 6012 fixed are not listed here). 6013 6014 GCC 5.5 6015 6016 This is the [44]list of problem reports (PRs) from GCC's bug tracking 6017 system that are known to be fixed in the 5.5 release. This list might 6018 not be complete (that is, it is possible that some PRs that have been 6019 fixed are not listed here). 6020 6021 Target Specific Changes 6022 6023 IA-32/x86-64 6024 6025 * Support for the [45]deprecated pcommit instruction has been 6026 removed. 6027 6028 6029 For questions related to the use of GCC, please consult these web 6030 pages and the [46]GCC manuals. If that fails, the 6031 [47]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6032 web pages and the development of GCC are welcome on our developer 6033 list at [48]gcc (a] gcc.gnu.org. All of [49]our lists have public 6034 archives. 6035 6036 Copyright (C) [50]Free Software Foundation, Inc. Verbatim copying and 6037 distribution of this entire article is permitted in any medium, 6038 provided this notice is preserved. 6039 6040 These pages are [51]maintained by the GCC team. Last modified 6041 2020-05-31[52]. 6042 6043 References 6044 6045 1. http://gcc.gnu.org/gcc-5/changes.html#libstdcxx 6046 2. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 6047 3. https://savannah.nongnu.org/bugs/?44574 6048 4. https://gcc.gnu.org/wiki/Intel%20MPX%20support%20in%20the%20GCC%20compiler 6049 5. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.pdf 6050 6. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.Examples.pdf 6051 7. https://gcc.gnu.org/wiki/OpenACC 6052 8. https://gcc.gnu.org/install/configure.html 6053 9. https://www.cilkplus.org/ 6054 10. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 6055 11. http://gcc.gnu.org/projects/cxx1y.html 6056 12. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations 6057 13. http://gcc.gnu.org/projects/cxx1y.html 6058 14. http://gcc.gnu.org/projects/cxx1y.html 6059 15. http://gcc.gnu.org/projects/cxx1y.html 6060 16. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3639.html 6061 17. http://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html 6062 18. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2011 6063 19. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 6064 20. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014 6065 21. https://sourceware.org/gdb/current/onlinedocs/gdb/Xmethods-In-Python.html 6066 22. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Error-and-Warning-Options.html 6067 23. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Language-Independent-Options.html 6068 24. https://gcc.gnu.org/install/configure.html 6069 25. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Thread-safety-of-the-runtime-library.html 6070 26. https://gcc.gnu.org/wiki/Fortran2003Status 6071 27. https://gcc.gnu.org/wiki/Fortran2008Status 6072 28. https://gcc.gnu.org/wiki/Coarray 6073 29. http://www.opencoarrays.org/ 6074 30. https://golang.org/cmd/go/ 6075 31. https://golang.org/cmd/gofmt/ 6076 32. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/index.html 6077 33. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/cp/index.html 6078 34. https://github.com/davidmalcolm/pygccjit 6079 35. https://github.com/ibuclaw/gccjitd 6080 36. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial04.html 6081 37. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial05.html 6082 38. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html 6083 39. https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html 6084 40. https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf 6085 41. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.2 6086 42. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.3 6087 43. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.4 6088 44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.5 6089 45. https://software.intel.com/content/www/us/en/develop/blogs/deprecate-pcommit-instruction.html 6090 46. https://gcc.gnu.org/onlinedocs/ 6091 47. mailto:gcc-help (a] gcc.gnu.org 6092 48. mailto:gcc (a] gcc.gnu.org 6093 49. https://gcc.gnu.org/lists.html 6094 50. https://www.fsf.org/ 6095 51. https://gcc.gnu.org/about.html 6096 52. http://validator.w3.org/check/referer 6097 ====================================================================== 6098 http://gcc.gnu.org/gcc-4.9/index.html 6099 6100 GCC 4.9 Release Series 6101 6102 (This release series is no longer supported.) 6103 6104 Aug 3, 2016 6105 6106 The [1]GNU project and the GCC developers are pleased to announce the 6107 release of GCC 4.9.4. 6108 6109 This release is a bug-fix release, containing fixes for regressions in 6110 GCC 4.9.3 relative to previous releases of GCC. 6111 6112 Release History 6113 6114 GCC 4.9.4 6115 Aug 3, 2016 ([2]changes, [3]documentation) 6116 6117 GCC 4.9.3 6118 June 26, 2015 ([4]changes, [5]documentation) 6119 6120 GCC 4.9.2 6121 October 30, 2014 ([6]changes, [7]documentation) 6122 6123 GCC 4.9.1 6124 July 16, 2014 ([8]changes, [9]documentation) 6125 6126 GCC 4.9.0 6127 April 22, 2014 ([10]changes, [11]documentation) 6128 6129 References and Acknowledgements 6130 6131 GCC used to stand for the GNU C Compiler, but since the compiler 6132 supports several other languages aside from C, it now stands for the 6133 GNU Compiler Collection. 6134 6135 A list of [12]successful builds is updated as new information becomes 6136 available. 6137 6138 The GCC developers would like to thank the numerous people that have 6139 contributed new features, improvements, bug fixes, and other changes as 6140 well as test results to GCC. This [13]amazing group of volunteers is 6141 what makes GCC successful. 6142 6143 For additional information about GCC please refer to the [14]GCC 6144 project web site or contact the [15]GCC development mailing list. 6145 6146 To obtain GCC please use [16]our mirror sites or [17]our version 6147 control system. 6148 6149 6150 For questions related to the use of GCC, please consult these web 6151 pages and the [18]GCC manuals. If that fails, the 6152 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6153 web pages and the development of GCC are welcome on our developer 6154 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 6155 archives. 6156 6157 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 6158 distribution of this entire article is permitted in any medium, 6159 provided this notice is preserved. 6160 6161 These pages are [23]maintained by the GCC team. Last modified 6162 2020-01-14[24]. 6163 6164 References 6165 6166 1. http://www.gnu.org/ 6167 2. http://gcc.gnu.org/gcc-4.9/changes.html 6168 3. http://gcc.gnu.org/onlinedocs/4.9.4/ 6169 4. http://gcc.gnu.org/gcc-4.9/changes.html 6170 5. http://gcc.gnu.org/onlinedocs/4.9.3/ 6171 6. http://gcc.gnu.org/gcc-4.9/changes.html 6172 7. http://gcc.gnu.org/onlinedocs/4.9.2/ 6173 8. http://gcc.gnu.org/gcc-4.9/changes.html 6174 9. http://gcc.gnu.org/onlinedocs/4.9.1/ 6175 10. http://gcc.gnu.org/gcc-4.9/changes.html 6176 11. https://gcc.gnu.org/onlinedocs/4.9.0/ 6177 12. http://gcc.gnu.org/gcc-4.9/buildstat.html 6178 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 6179 14. http://gcc.gnu.org/index.html 6180 15. mailto:gcc (a] gcc.gnu.org 6181 16. http://gcc.gnu.org/mirrors.html 6182 17. http://gcc.gnu.org/git.html 6183 18. https://gcc.gnu.org/onlinedocs/ 6184 19. mailto:gcc-help (a] gcc.gnu.org 6185 20. mailto:gcc (a] gcc.gnu.org 6186 21. https://gcc.gnu.org/lists.html 6187 22. https://www.fsf.org/ 6188 23. https://gcc.gnu.org/about.html 6189 24. http://validator.w3.org/check/referer 6190 ====================================================================== 6191 http://gcc.gnu.org/gcc-4.9/changes.html 6192 6193 GCC 4.9 Release Series 6194 Changes, New Features, and Fixes 6195 6196 Caveats 6197 6198 * The mudflap run time checker has been removed. The mudflap options 6199 remain, but do nothing. 6200 * Support for a number of older systems and recently unmaintained or 6201 untested target ports of GCC has been declared obsolete in GCC 4.9. 6202 Unless there is activity to revive them, the next release of GCC 6203 will have their sources permanently removed. 6204 The following ports for individual systems on particular 6205 architectures have been obsoleted: 6206 + Solaris 9 (*-*-solaris2.9). Details can be found in the 6207 [1]announcement. 6208 * On AArch64, the singleton vector types int64x1_t, uint64x1_t and 6209 float64x1_t exported by arm_neon.h are defined to be the same as 6210 their base types. This results in incorrect application of 6211 parameter passing rules to arguments of types int64x1_t and 6212 uint64x1_t, with respect to the AAPCS64 ABI specification. In 6213 addition, names of C++ functions with parameters of these types 6214 (including float64x1_t) are not mangled correctly. The current 6215 typedef declarations also unintentionally allow implicit casting 6216 between singleton vector types and their base types. These issues 6217 will be resolved in a near future release. See [2]PR60825 for more 6218 information. 6219 6220 More information on porting to GCC 4.9 from previous versions of GCC 6221 can be found in the [3]porting guide for this release. 6222 6223 General Optimizer Improvements 6224 6225 * AddressSanitizer, a fast memory error detector, is now available on 6226 ARM. 6227 * UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior 6228 detector, has been added and can be enabled via 6229 -fsanitize=undefined. Various computations will be instrumented to 6230 detect undefined behavior at runtime. UndefinedBehaviorSanitizer is 6231 currently available for the C and C++ languages. 6232 * Link-time optimization (LTO) improvements: 6233 + Type merging was rewritten. The new implementation is 6234 significantly faster and uses less memory. 6235 + Better partitioning algorithm resulting in less streaming 6236 during link time. 6237 + Early removal of virtual methods reduces the size of object 6238 files and improves link-time memory usage and compile time. 6239 + Function bodies are now loaded on-demand and released early 6240 improving overall memory usage at link time. 6241 + C++ hidden keyed methods can now be optimized out. 6242 + When using a linker plugin, compiling with the -flto option 6243 now generates slim object files (.o) which only contain 6244 intermediate language representation for LTO. Use 6245 -ffat-lto-objects to create files which contain additionally 6246 the object code. To generate static libraries suitable for LTO 6247 processing, use gcc-ar and gcc-ranlib; to list symbols from a 6248 slim object file use gcc-nm. (This requires that ar, ranlib 6249 and nm have been compiled with plugin support.) 6250 Memory usage building Firefox with debug enabled was reduced from 6251 15GB to 3.5GB; link time from 1700 seconds to 350 seconds. 6252 * Inter-procedural optimization improvements: 6253 + New type inheritance analysis module improving 6254 devirtualization. Devirtualization now takes into account 6255 anonymous name-spaces and the C++11 final keyword. 6256 + New speculative devirtualization pass (controlled by 6257 -fdevirtualize-speculatively. 6258 + Calls that were speculatively made direct are turned back to 6259 indirect where direct call is not cheaper. 6260 + Local aliases are introduced for symbols that are known to be 6261 semantically equivalent across shared libraries improving 6262 dynamic linking times. 6263 * Feedback directed optimization improvements: 6264 + Profiling of programs using C++ inline functions is now more 6265 reliable. 6266 + New time profiling determines typical order in which functions 6267 are executed. 6268 + A new function reordering pass (controlled by 6269 -freorder-functions) significantly reduces startup time of 6270 large applications. Until binutils support is completed, it is 6271 effective only with link-time optimization. 6272 + Feedback driven indirect call removal and devirtualization now 6273 handle cross-module calls when link-time optimization is 6274 enabled. 6275 6276 New Languages and Language specific improvements 6277 6278 * Version 4.0 of the [4]OpenMP specification is now supported in the 6279 C and C++ compilers and starting with the 4.9.1 release also in the 6280 Fortran compiler. The new -fopenmp-simd option can be used to 6281 enable OpenMP's SIMD directives while ignoring other OpenMP 6282 directives. The new [5]-fsimd-cost-model= option permits to tune 6283 the vectorization cost model for loops annotated with OpenMP and 6284 Cilk Plus simd directives. -Wopenmp-simd warns when the current 6285 cost model overrides simd directives set by the user. 6286 * The -Wdate-time option has been added for the C, C++ and Fortran 6287 compilers, which warns when the __DATE__, __TIME__ or __TIMESTAMP__ 6288 macros are used. Those macros might prevent bit-wise-identical 6289 reproducible compilations. 6290 6291 Ada 6292 6293 * GNAT switched to Ada 2012 instead of Ada 2005 by default. 6294 6295 C family 6296 6297 * Support for colorizing diagnostics emitted by GCC has been added. 6298 The [6]-fdiagnostics-color=auto will enable it when outputting to 6299 terminals, -fdiagnostics-color=always unconditionally. The 6300 GCC_COLORS environment variable can be used to customize the colors 6301 or disable coloring. If GCC_COLORS variable is present in the 6302 environment, the default is -fdiagnostics-color=auto, otherwise 6303 -fdiagnostics-color=never. 6304 Sample diagnostics output: 6305 $ g++ -fdiagnostics-color=always -S -Wall test.C 6306 test.C: In function `int foo()': 6307 test.C:1:14: warning: no return statement in function returning non-void [-W 6308 return-type] 6309 int foo () { } 6310 ^ 6311 test.C:2:46: error: template instantiation depth exceeds maximum of 900 (use 6312 -ftemplate-depth= to increase the maximum) instantiating `struct X<100>' 6313 template <int N> struct X { static const int value = X<N-1>::value; }; temp 6314 late struct X<1000>; 6315 ^ 6316 test.C:2:46: recursively required from `const int X<999>::value' 6317 test.C:2:46: required from `const int X<1000>::value' 6318 test.C:2:88: required from here 6319 6320 test.C:2:46: error: incomplete type `X<100>' used in nested name specifier 6321 6322 * With the new [7]#pragma GCC ivdep, the user can assert that there 6323 are no loop-carried dependencies which would prevent concurrent 6324 execution of consecutive iterations using SIMD (single instruction 6325 multiple data) instructions. 6326 * Support for Cilk Plus has been added and can be enabled with the 6327 -fcilkplus option. Cilk Plus is an extension to the C and C++ 6328 languages to support data and task parallelism. The present 6329 implementation follows ABI version 1.2; all features but _Cilk_for 6330 have been implemented. 6331 6332 C 6333 6334 * ISO C11 atomics (the _Atomic type specifier and qualifier and the 6335 <stdatomic.h> header) are now supported. 6336 * ISO C11 generic selections (_Generic keyword) are now supported. 6337 * ISO C11 thread-local storage (_Thread_local, similar to GNU C 6338 __thread) is now supported. 6339 * ISO C11 support is now at a similar level of completeness to ISO 6340 C99 support: substantially complete modulo bugs, extended 6341 identifiers (supported except for corner cases when 6342 -fextended-identifiers is used), floating-point issues (mainly but 6343 not entirely relating to optional C99 features from Annexes F and 6344 G) and the optional Annexes K (Bounds-checking interfaces) and L 6345 (Analyzability). 6346 * A new C extension __auto_type provides a subset of the 6347 functionality of C++11 auto in GNU C. 6348 6349 C++ 6350 6351 * The G++ implementation of [8]C++1y return type deduction for normal 6352 functions has been updated to conform to [9]N3638, the proposal 6353 accepted into the working paper. Most notably, it adds 6354 decltype(auto) for getting decltype semantics rather than the 6355 template argument deduction semantics of plain auto: 6356 6357 int& f(); 6358 auto i1 = f(); // int 6359 decltype(auto) i2 = f(); // int& 6360 6361 * G++ supports [10]C++1y lambda capture initializers: 6362 6363 [x = 42]{ ... }; 6364 6365 Actually, they have been accepted since GCC 4.5, but now the 6366 compiler doesn't warn about them with -std=c++1y, and supports 6367 parenthesized and brace-enclosed initializers as well. 6368 * G++ supports [11]C++1y variable length arrays. G++ has supported 6369 GNU/C99-style VLAs for a long time, but now additionally supports 6370 initializers and lambda capture by reference. In C++1y mode G++ 6371 will complain about VLA uses that are not permitted by the draft 6372 standard, such as forming a pointer to VLA type or applying sizeof 6373 to a VLA variable. Note that it now appears that VLAs will not be 6374 part of C++14, but will be part of a separate document and then 6375 perhaps C++17. 6376 6377 void f(int n) { 6378 int a[n] = { 1, 2, 3 }; // throws std::bad_array_length if n < 3 6379 [&a]{ for (int i : a) { cout << i << endl; } }(); 6380 &a; // error, taking address of VLA 6381 } 6382 6383 * G++ supports the [12]C++1y [[deprecated]] attribute modulo bugs in 6384 the underlying [[gnu::deprecated]] attribute. Classes and functions 6385 can be marked deprecated and a diagnostic message added: 6386 6387 class A; 6388 int bar(int n); 6389 #if __cplusplus > 201103 6390 class [[deprecated("A is deprecated in C++14; Use B instead")]] A; 6391 [[deprecated("bar is unsafe; use foo() instead")]] 6392 int bar(int n); 6393 6394 int foo(int n); 6395 class B; 6396 #endif 6397 A aa; // warning: 'A' is deprecated : A is deprecated in C++14; Use B instead 6398 int j = bar(2); // warning: 'int bar(int)' is deprecated : bar is unsafe; use fo 6399 o() instead 6400 6401 * G++ supports [13]C++1y digit separators. Long numeric literals can 6402 be subdivided with a single quote ' to enhance readability: 6403 6404 int i = 1048576; 6405 int j = 1'048'576; 6406 int k = 0x10'0000; 6407 int m = 0'004'000'000; 6408 int n = 0b0001'0000'0000'0000'0000'0000; 6409 6410 double x = 1.602'176'565e-19; 6411 double y = 1.602'176'565e-1'9; 6412 6413 * G++ supports [14]C++1y generic (polymorphic) lambdas. 6414 6415 // a functional object that will increment any type 6416 auto incr = [](auto x) { return x++; }; 6417 6418 * As a GNU extension, G++ supports explicit template parameter syntax 6419 for generic lambdas. This can be combined in the expected way with 6420 the standard auto syntax. 6421 6422 // a functional object that will add two like-type objects 6423 auto add = [] <typename T> (T a, T b) { return a + b; }; 6424 6425 * G++ supports unconstrained generic functions as specified by 4.1.2 6426 and 5.1.1 of [15]N3889: Concepts Lite Specification. Briefly, auto 6427 may be used as a type-specifier in a parameter declaration of any 6428 function declarator in order to introduce an implicit function 6429 template parameter, akin to generic lambdas. 6430 6431 // the following two function declarations are equivalent 6432 auto incr(auto x) { return x++; } 6433 template <typename T> 6434 auto incr(T x) { return x++; } 6435 6436 Runtime Library (libstdc++) 6437 6438 * [16]Improved support for C++11, including: 6439 + support for <regex>; 6440 + The associative containers in <map> and <set> and the 6441 unordered associative containers in <unordered_map> and 6442 <unordered_set> meet the allocator-aware container 6443 requirements; 6444 * [17]Improved experimental support for the upcoming ISO C++ 6445 standard, C++14, including: 6446 + fixing constexpr member functions without const; 6447 + implementation of the std::exchange() utility function; 6448 + addressing tuples by type; 6449 + implemention of std::make_unique; 6450 + implemention of std::shared_lock; 6451 + making std::result_of SFINAE-friendly; 6452 + adding operator() to std::integral_constant; 6453 + adding user-defined literals for standard library types 6454 std::basic_string, std::chrono::duration, and std::complex; 6455 + adding two range overloads to non-modifying sequence oprations 6456 std::equal and std::mismatch; 6457 + adding IO manipulators for quoted strings; 6458 + adding constexpr members to <utility>, <complex>, <chrono>, 6459 and some containers; 6460 + adding compile-time std::integer_sequence; 6461 + adding cleaner transformation traits; 6462 + making <functional>s operator functors easier to use and more 6463 generic; 6464 * An implementation of std::experimental::optional. 6465 * An implementation of std::experimental::string_view. 6466 * The non-standard function std::copy_exception has been deprecated 6467 and will be removed in a future version. std::make_exception_ptr 6468 should be used instead. 6469 6470 Fortran 6471 6472 * Compatibility notice: 6473 + Module files: The version of the module files (.mod) has been 6474 incremented; additionally, module files are now compressed. 6475 Fortran MODULEs compiled by earlier GCC versions have to be 6476 recompiled, when they are USEd by files compiled with GCC 4.9. 6477 GCC 4.9 is not able to read .mod files of earlier GCC 6478 versions; attempting to do so gives an error message. Note: 6479 The ABI of the produced assembler data itself has not changed: 6480 object files and libraries are fully compatible with older 6481 versions (except as stated below). 6482 + ABI changes: 6483 o The [18]argument passing ABI has changed for scalar dummy 6484 arguments of type INTEGER, REAL, COMPLEX and LOGICAL, 6485 which have both the VALUE and the OPTIONAL attributes. 6486 o To support finalization the virtual table associated with 6487 polymorphic variables has changed. Code containing CLASS 6488 should be recompiled, including all files which define 6489 derived types involved in the type definition used by 6490 polymorphic variables. (Note: Due to the incremented 6491 module version, trying to mix old code with new code will 6492 usually give an error message.) 6493 + GNU Fortran no longer deallocates allocatable variables or 6494 allocatable components of variables declared in the main 6495 program. Since Fortran 2008, the standard explicitly states 6496 that variables declared in the Fortran main program 6497 automatically have the SAVE attribute. 6498 + When opening files, the close-on-exec flag is set if the 6499 system supports such a feature. This is generally considered 6500 good practice these days, but if there is a need to pass file 6501 descriptors to child processes the parent process must now 6502 remember to clear the close-on-exec flag by calling fcntl(), 6503 e.g. via ISO_C_BINDING, before executing the child process. 6504 * The deprecated command-line option -fno-whole-file has been 6505 removed. (-fwhole-file is the default since GCC 4.6.) 6506 -fwhole-file/-fno-whole-file continue to be accepted but do not 6507 influence the code generation. 6508 * The compiler no longer unconditionally warns about DO loops with 6509 zero iterations. This warning is now controlled by the -Wzerotrip 6510 option, which is implied by -Wall. 6511 * The new NO_ARG_CHECK attribute of the [19]!GCC$ directive can be 6512 used to disable the type-kind-rank (TKR) argument check for a dummy 6513 argument. The feature is similar to ISO/IEC TS 29133:2012's 6514 TYPE(*), except that it additionally also disables the rank check. 6515 Variables with NO_ARG_CHECK have to be dummy arguments and may only 6516 be used as argument to ISO_C_BINDING's C_LOC and as actual argument 6517 to another NO_ARG_CHECK dummy argument; also the other constraints 6518 of TYPE(*) apply. The dummy arguments should be declared as scalar 6519 or assumed-size variable of type type(*) (recommended) - or of type 6520 integer, real, complex or logical. With NO_ARG_CHECK, a pointer to 6521 the data without further type or shape information is passed, 6522 similar to C's void*. Note that also TS 29113's 6523 type(*),dimension(..) accepts arguments of any type and rank; 6524 contrary to NO_ARG_CHECK assumed-rank arguments pass an array 6525 descriptor which contains the array shape and stride of the 6526 argument. 6527 * [20]Fortran 2003: 6528 + Finalization is now supported. It is currently only done for a 6529 subset of those situations in which it should occur. 6530 + Experimental support for scalar character components with 6531 deferred length (i.e. allocatable string length) in derived 6532 types has been added. (Deferred-length character variables are 6533 supported since GCC 4.6.) 6534 * [21]Fortran 2008: 6535 + When STOP or ERROR STOP are used to terminate the execution 6536 and any exception (but inexact) is signaling, a warning is 6537 printed to ERROR_UNIT, indicating which exceptions are 6538 signaling. The [22]-ffpe-summary= command-line option can be 6539 used to fine-tune for which exceptions the warning should be 6540 shown. 6541 + Rounding on input (READ) is now handled on systems where 6542 strtod honours the rounding mode. (For output, rounding is 6543 supported since GCC 4.5.) Note that for input, the compatible 6544 rounding mode is handled as nearest (i.e., rounding to an even 6545 least significant [cf. IEC 60559:1989] for a tie, while 6546 compatible rounds away from zero in that case). 6547 6548 Go 6549 6550 * GCC 4.9 provides a complete implementation of the Go 1.2.1 release. 6551 6552 New Targets and Target Specific Improvements 6553 6554 AArch64 6555 6556 * The ARMv8-A crypto and CRC instructions are now supported through 6557 intrinsics. These are enabled when the architecture supports these 6558 and are available through the -march=armv8-a+crc and 6559 -march=armv8-a+crypto options. 6560 * Initial support for ILP32 has now been added to the compiler. This 6561 is now available through the command-line option -mabi=ilp32. 6562 Support for ILP32 is considered experimental as the ABI 6563 specification is still beta. 6564 * Coverage of more of the ISA including the SIMD extensions has been 6565 added. The Advanced SIMD intrinsics have also been improved. 6566 * The new local register allocator (LRA) is now on by default for the 6567 AArch64 backend. 6568 * The REE (Redundant extension elimination) pass has now been enabled 6569 by default for the AArch64 backend. 6570 * Tuning for the Cortex-A53 and Cortex-A57 has been improved. 6571 * Initial big.LITTLE tuning support for the combination of Cortex-A57 6572 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 6573 option. 6574 * A number of structural changes have been made to both the ARM and 6575 AArch64 backends to facilitate improved code-generation. 6576 * As of GCC 4.9.2 a workaround for the ARM Cortex-A53 erratum 835769 6577 has been added and can be enabled by giving the 6578 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 6579 default by configuring GCC with the --enable-fix-cortex-a53-835769 6580 option. 6581 6582 ARC 6583 6584 * A port for Synopsys Designware ARC has been contributed by Embecosm 6585 and Synopsys Inc. 6586 6587 ARM 6588 6589 * Use of Advanced SIMD (Neon) for 64-bit scalar computations has been 6590 disabled by default. This was found to generate better code in only 6591 a small number of cases. It can be turned back on with the 6592 -mneon-for-64bits option. 6593 * Further support for the ARMv8-A architecture, notably implementing 6594 the restriction around IT blocks in the Thumb32 instruction set has 6595 been added. The -mrestrict-it option can be used with 6596 -march=armv7-a or the -march=armv7ve options to make code 6597 generation fully compatible with the deprecated instructions in 6598 ARMv8-A. 6599 * Support has now been added for the ARMv7ve variant of the 6600 architecture. This can be used by the -march=armv7ve option. 6601 * The ARMv8-A crypto and CRC instructions are now supported through 6602 intrinsics and are available through the -march=armv8-a+crc and 6603 mfpu=crypto-neon-fp-armv8 options. 6604 * LRA is now on by default for the ARM target. This can be turned off 6605 using the -mno-lra option. This option is a purely transitionary 6606 command-line option and will be removed in a future release. We are 6607 interested in any bug reports regarding functional and performance 6608 regressions with LRA. 6609 * A new option -mslow-flash-data to improve performance of programs 6610 fetching data on slow flash memory has now been introduced for the 6611 ARMv7-M profile cores. 6612 * A new option -mpic-data-is-text-relative for targets that allows 6613 data segments to be relative to text segments has been added. This 6614 is on by default for all targets except VxWorks RTP. 6615 * A number of infrastructural changes have been made to both the ARM 6616 and AArch64 backends to facilitate improved code-generation. 6617 * GCC now supports Cortex-A12 and the Cortex-R7 through the 6618 -mcpu=cortex-a12 and -mcpu=cortex-r7 options. 6619 * GCC now has tuning for the Cortex-A57 and Cortex-A53 through the 6620 -mcpu=cortex-a57 and -mcpu=cortex-a53 options. 6621 * Initial big.LITTLE tuning support for the combination of Cortex-A57 6622 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53 6623 option. Similar support was added for the combination of Cortex-A15 6624 and Cortex-A7 through the -mcpu=cortex-a15.cortex-a7 option. 6625 * Further performance optimizations for the Cortex-A15 and the 6626 Cortex-M4 have been added. 6627 * A number of code generation improvements for Thumb2 to reduce code 6628 size when compiling for the M-profile processors. 6629 6630 AVR 6631 6632 * A new command-line option -mfract-convert-truncate has been added. 6633 It allows compiler to use truncation instead of rounding towards 6634 zero for fractional fixed-point types. 6635 6636 IA-32/x86-64 6637 6638 * -mfpmath=sse is now implied by -ffast-math on all targets where 6639 SSE2 is supported. 6640 * Intel AVX-512 support was added to GCC. That includes inline 6641 assembly support, new registers and extending existing ones, new 6642 intrinsics (covered by corresponding testsuite), and basic 6643 autovectorization. AVX-512 instructions are available via the 6644 following GCC switches: AVX-512 foundation instructions: -mavx512f, 6645 AVX-512 prefetch instructions: -mavx512pf, AVX-512 exponential and 6646 reciprocal instructions: -mavx512er, AVX-512 conflict detection 6647 instructions: -mavx512cd. 6648 * It is now possible to call x86 intrinsics from select functions in 6649 a file that are tagged with the corresponding target attribute 6650 without having to compile the entire file with the -mxxx option. 6651 This improves the usability of x86 intrinsics and is particularly 6652 useful when doing [23]Function Multiversioning. 6653 * GCC now supports the new Intel microarchitecture named Silvermont 6654 through -march=silvermont. 6655 * GCC now supports the new Intel microarchitecture named Broadwell 6656 through -march=broadwell. 6657 * Optimizing for other Intel microarchitectures have been renamed to 6658 -march=nehalem, westmere, sandybridge, ivybridge, haswell, bonnell. 6659 * -march=generic has been retuned for better support of Intel core 6660 and AMD Bulldozer architectures. Performance of AMD K7, K8, Intel 6661 Pentium-M, and Pentium4 based CPUs is no longer considered 6662 important for generic. 6663 * -mtune=intel can now be used to generate code running well on the 6664 most current Intel processors, which are Haswell and Silvermont for 6665 GCC 4.9. 6666 * Support to encode 32-bit assembly instructions in 16-bit format is 6667 now available through the -m16 command-line option. 6668 * Better inlining of memcpy and memset that is aware of value ranges 6669 and produces shorter alignment prologues. 6670 * -mno-accumulate-outgoing-args is now honored when unwind 6671 information is output. Argument accumulation is also now turned off 6672 for portions of programs optimized for size. 6673 * Support for new AMD family 15h processors (Excavator core) is now 6674 available through the -march=bdver4 and -mtune=bdver4 options. 6675 6676 MSP430 6677 6678 * A new command-line option -mcpu= has been added to the MSP430 6679 backend. This option is used to specify the ISA to be used. 6680 Accepted values are msp430 (the default), msp430x and msp430xv2. 6681 The ISA is no longer deduced from the -mmcu= option as there are 6682 far too many different MCU names. The -mmcu= option is still 6683 supported, and this is still used to select linker scripts and 6684 generate a C preprocessor symbol that will be recognised by the 6685 msp430.h header file. 6686 6687 NDS32 6688 6689 * A new nds32 port supports the 32-bit architecture from Andes 6690 Technology Corporation. 6691 * The port provides initial support for the V2, V3, V3m instruction 6692 set architectures. 6693 6694 Nios II 6695 6696 * A port for the Altera Nios II has been contributed by Mentor 6697 Graphics. 6698 6699 PowerPC / PowerPC64 / RS6000 6700 6701 * GCC now supports Power ISA 2.07, which includes support for 6702 Hardware Transactional Memory (HTM), Quadword atomics and several 6703 VMX and VSX additions, including Crypto, 64-bit integer, 128-bit 6704 integer and decimal integer operations. 6705 * Support for the POWER8 processor is now available through the 6706 -mcpu=power8 and -mtune=power8 options. 6707 * The libitm library has been modified to add a HTM fastpath that 6708 automatically uses POWER's HTM hardware instructions when it is 6709 executing on a HTM enabled processor. 6710 * Support for the new powerpc64le-linux platform has been added. It 6711 defaults to generating code that conforms to the ELFV2 ABI. 6712 6713 S/390, System z 6714 6715 * Support for the Transactional Execution Facility included with the 6716 IBM zEnterprise zEC12 processor has been added. A set of GCC style 6717 builtins as well as XLC style builtins are provided. The builtins 6718 are enabled by default when using the -march=zEC12 option but can 6719 explicitly be disabled with -mno-htm. Using the GCC builtins also 6720 libitm supports hardware transactions on S/390. 6721 * The hotpatch features allows to prepare functions for hotpatching. 6722 A certain amount of bytes is reserved before the function entry 6723 label plus a NOP is inserted at its very beginning to implement a 6724 backward jump when applying a patch. The feature can either be 6725 enabled per compilation unit via the command-line option -mhotpatch 6726 or per function using the hotpatch attribute. 6727 * The shrink wrap optimization is now supported on S/390 and enabled 6728 by default. 6729 * A major rework of the routines to determine which registers need to 6730 be saved and restored in function prologue/epilogue now allow to 6731 use floating point registers as save slots. This will happen for 6732 certain leaf function with -march=z10 or higher. 6733 * The LRA rtl pass replaces reload by default on S/390. 6734 6735 RX 6736 6737 * The port now allows to specify the RX100, RX200, and RX600 6738 processors with the command-line options -mcpu=rx100, -mcpu=rx200 6739 and -mcpu=rx600. 6740 6741 SH 6742 6743 * Minor improvements to code generated for integer arithmetic and 6744 code that involves the T bit. 6745 * Added support for the SH2A clips and clipu instructions. The 6746 compiler will now try to utilize them for min/max expressions such 6747 as max (-128, min (127, x)). 6748 * Added support for the cmp/str instruction through built-in 6749 functions such as __builtin_strlen. When not optimizing for size, 6750 the compiler will now expand calls to e.g. strlen as an inlined 6751 sequences which utilize the cmp/str instruction. 6752 * Improved code generated around volatile memory loads and stores. 6753 * The option -mcbranchdi has been deprecated. Specifying it will 6754 result in a warning and will not influence code generation. 6755 * The option -mcmpeqdi has been deprecated. Specifying it will result 6756 in a warning and will not influence code generation. 6757 6758 GCC 4.9.1 6759 6760 This is the [24]list of problem reports (PRs) from GCC's bug tracking 6761 system that are known to be fixed in the 4.9.1 release. This list might 6762 not be complete (that is, it is possible that some PRs that have been 6763 fixed are not listed here). 6764 6765 Version 4.0 of the OpenMP specification is supported even in Fortran, 6766 not just C and C++. 6767 6768 GCC 4.9.2 6769 6770 This is the [25]list of problem reports (PRs) from GCC's bug tracking 6771 system that are known to be fixed in the 4.9.2 release. This list might 6772 not be complete (that is, it is possible that some PRs that have been 6773 fixed are not listed here). 6774 6775 GCC 4.9.3 6776 6777 This is the [26]list of problem reports (PRs) from GCC's bug tracking 6778 system that are known to be fixed in the 4.9.3 release. This list might 6779 not be complete (that is, it is possible that some PRs that have been 6780 fixed are not listed here). 6781 6782 GCC 4.9.4 6783 6784 This is the [27]list of problem reports (PRs) from GCC's bug tracking 6785 system that are known to be fixed in the 4.9.4 release. This list might 6786 not be complete (that is, it is possible that some PRs that have been 6787 fixed are not listed here). 6788 6789 6790 For questions related to the use of GCC, please consult these web 6791 pages and the [28]GCC manuals. If that fails, the 6792 [29]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6793 web pages and the development of GCC are welcome on our developer 6794 list at [30]gcc (a] gcc.gnu.org. All of [31]our lists have public 6795 archives. 6796 6797 Copyright (C) [32]Free Software Foundation, Inc. Verbatim copying and 6798 distribution of this entire article is permitted in any medium, 6799 provided this notice is preserved. 6800 6801 These pages are [33]maintained by the GCC team. Last modified 6802 2021-03-31[34]. 6803 6804 References 6805 6806 1. https://gcc.gnu.org/ml/gcc-patches/2013-05/msg00728.html 6807 2. https://gcc.gnu.org/PR60825 6808 3. https://gcc.gnu.org/gcc-4.9/porting_to.html 6809 4. https://www.openmp.org/specifications/ 6810 5. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Optimize-Options.html#index-fsimd-cost-model-908 6811 6. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Language-Independent-Options.html#index-fdiagnostics-color-252 6812 7. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Loop-Specific-Pragmas.html 6813 8. http://gcc.gnu.org/projects/cxx1y.html 6814 9. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3638.html 6815 10. http://gcc.gnu.org/projects/cxx1y.html 6816 11. http://gcc.gnu.org/projects/cxx1y.html 6817 12. http://gcc.gnu.org/projects/cxx1y.html 6818 13. http://gcc.gnu.org/projects/cxx1y.html 6819 14. http://gcc.gnu.org/projects/cxx1y.html 6820 15. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3889.pdf 6821 16. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/libstdc++/manual/manual/status.html#status.iso.2011 6822 17. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2014 6823 18. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Argument-passing-conventions.html 6824 19. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/GNU-Fortran-Compiler-Directives.html 6825 20. https://gcc.gnu.org/wiki/Fortran2003Status 6826 21. https://gcc.gnu.org/wiki/Fortran2008Status 6827 22. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Debugging-Options.html 6828 23. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Function-Multiversioning.html 6829 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.1 6830 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.2 6831 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.3 6832 27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.4 6833 28. https://gcc.gnu.org/onlinedocs/ 6834 29. mailto:gcc-help (a] gcc.gnu.org 6835 30. mailto:gcc (a] gcc.gnu.org 6836 31. https://gcc.gnu.org/lists.html 6837 32. https://www.fsf.org/ 6838 33. https://gcc.gnu.org/about.html 6839 34. http://validator.w3.org/check/referer 6840 ====================================================================== 6841 http://gcc.gnu.org/gcc-4.8/index.html 6842 6843 GCC 4.8 Release Series 6844 6845 (This release series is no longer supported.) 6846 6847 June 23, 2015 6848 6849 The [1]GNU project and the GCC developers are pleased to announce the 6850 release of GCC 4.8.5. 6851 6852 This release is a bug-fix release, containing fixes for regressions in 6853 GCC 4.8.4 relative to previous releases of GCC. 6854 6855 Release History 6856 6857 GCC 4.8.5 6858 June 23, 2015 ([2]changes, [3]documentation) 6859 6860 GCC 4.8.4 6861 December 19, 2014 ([4]changes, [5]documentation) 6862 6863 GCC 4.8.3 6864 May 22, 2014 ([6]changes, [7]documentation) 6865 6866 GCC 4.8.2 6867 October 16, 2013 ([8]changes, [9]documentation) 6868 6869 GCC 4.8.1 6870 May 31, 2013 ([10]changes, [11]documentation) 6871 6872 GCC 4.8.0 6873 March 22, 2013 ([12]changes, [13]documentation) 6874 6875 References and Acknowledgements 6876 6877 GCC used to stand for the GNU C Compiler, but since the compiler 6878 supports several other languages aside from C, it now stands for the 6879 GNU Compiler Collection. 6880 6881 A list of [14]successful builds is updated as new information becomes 6882 available. 6883 6884 The GCC developers would like to thank the numerous people that have 6885 contributed new features, improvements, bug fixes, and other changes as 6886 well as test results to GCC. This [15]amazing group of volunteers is 6887 what makes GCC successful. 6888 6889 For additional information about GCC please refer to the [16]GCC 6890 project web site or contact the [17]GCC development mailing list. 6891 6892 To obtain GCC please use [18]our mirror sites or [19]our version 6893 control system. 6894 6895 6896 For questions related to the use of GCC, please consult these web 6897 pages and the [20]GCC manuals. If that fails, the 6898 [21]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 6899 web pages and the development of GCC are welcome on our developer 6900 list at [22]gcc (a] gcc.gnu.org. All of [23]our lists have public 6901 archives. 6902 6903 Copyright (C) [24]Free Software Foundation, Inc. Verbatim copying and 6904 distribution of this entire article is permitted in any medium, 6905 provided this notice is preserved. 6906 6907 These pages are [25]maintained by the GCC team. Last modified 6908 2020-01-14[26]. 6909 6910 References 6911 6912 1. http://www.gnu.org/ 6913 2. http://gcc.gnu.org/gcc-4.8/changes.html 6914 3. https://gcc.gnu.org/onlinedocs/4.8.5/ 6915 4. http://gcc.gnu.org/gcc-4.8/changes.html 6916 5. https://gcc.gnu.org/onlinedocs/4.8.4/ 6917 6. http://gcc.gnu.org/gcc-4.8/changes.html 6918 7. https://gcc.gnu.org/onlinedocs/4.8.3/ 6919 8. http://gcc.gnu.org/gcc-4.8/changes.html 6920 9. https://gcc.gnu.org/onlinedocs/4.8.2/ 6921 10. http://gcc.gnu.org/gcc-4.8/changes.html 6922 11. https://gcc.gnu.org/onlinedocs/4.8.1/ 6923 12. http://gcc.gnu.org/gcc-4.8/changes.html 6924 13. https://gcc.gnu.org/onlinedocs/4.8.0/ 6925 14. http://gcc.gnu.org/gcc-4.8/buildstat.html 6926 15. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 6927 16. http://gcc.gnu.org/index.html 6928 17. mailto:gcc (a] gcc.gnu.org 6929 18. http://gcc.gnu.org/mirrors.html 6930 19. http://gcc.gnu.org/git.html 6931 20. https://gcc.gnu.org/onlinedocs/ 6932 21. mailto:gcc-help (a] gcc.gnu.org 6933 22. mailto:gcc (a] gcc.gnu.org 6934 23. https://gcc.gnu.org/lists.html 6935 24. https://www.fsf.org/ 6936 25. https://gcc.gnu.org/about.html 6937 26. http://validator.w3.org/check/referer 6938 ====================================================================== 6939 http://gcc.gnu.org/gcc-4.8/changes.html 6940 6941 GCC 4.8 Release Series 6942 Changes, New Features, and Fixes 6943 6944 Caveats 6945 6946 GCC now uses C++ as its implementation language. This means that to 6947 build GCC from sources, you will need a C++ compiler that understands 6948 C++ 2003. For more details on the rationale and specific changes, 6949 please refer to the [1]C++ conversion page. 6950 6951 To enable the Graphite framework for loop optimizations you now need 6952 CLooG version 0.18.0 and ISL version 0.11.1. Both can be obtained from 6953 the [2]GCC infrastructure directory. The installation manual contains 6954 more information about requirements to build GCC. 6955 6956 GCC now uses a more aggressive analysis to derive an upper bound for 6957 the number of iterations of loops using constraints imposed by language 6958 standards. This may cause non-conforming programs to no longer work as 6959 expected, such as SPEC CPU 2006 464.h264ref and 416.gamess. A new 6960 option, -fno-aggressive-loop-optimizations, was added to disable this 6961 aggressive analysis. In some loops that have known constant number of 6962 iterations, but undefined behavior is known to occur in the loop before 6963 reaching or during the last iteration, GCC will warn about the 6964 undefined behavior in the loop instead of deriving lower upper bound of 6965 the number of iterations for the loop. The warning can be disabled with 6966 -Wno-aggressive-loop-optimizations. 6967 6968 On ARM, a bug has been fixed in GCC's implementation of the AAPCS rules 6969 for the layout of vectors that could lead to wrong code being 6970 generated. Vectors larger than 8 bytes in size are now by default 6971 aligned to an 8-byte boundary. This is an ABI change: code that makes 6972 explicit use of vector types may be incompatible with binary objects 6973 built with older versions of GCC. Auto-vectorized code is not affected 6974 by this change. 6975 6976 On AVR, support has been removed for the command-line option 6977 -mshort-calls deprecated in GCC 4.7. 6978 6979 On AVR, the configure option --with-avrlibc supported since GCC 4.7.2 6980 is turned on per default for all non-RTEMS configurations. This option 6981 arranges for a better integration of [3]AVR Libc with avr-gcc. For 6982 technical details, see [4]PR54461. To turn off the option in non-RTEMS 6983 configurations, use --with-avrlibc=no. If the compiler is configured 6984 for RTEMS, the option is always turned off. 6985 6986 More information on porting to GCC 4.8 from previous versions of GCC 6987 can be found in the [5]porting guide for this release. 6988 6989 General Optimizer Improvements (and Changes) 6990 6991 * DWARF4 is now the default when generating DWARF debug information. 6992 When -g is used on a platform that uses DWARF debugging 6993 information, GCC will now default to -gdwarf-4 6994 -fno-debug-types-section. 6995 GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information 6996 consumers support DWARF4 by default. Before GCC 4.8 the default 6997 version used was DWARF2. To make GCC 4.8 generate an older DWARF 6998 version use -g together with -gdwarf-2 or -gdwarf-3. The default 6999 for Darwin and VxWorks is still -gdwarf-2 -gstrict-dwarf. 7000 * A new general optimization level, -Og, has been introduced. It 7001 addresses the need for fast compilation and a superior debugging 7002 experience while providing a reasonable level of run-time 7003 performance. Overall experience for development should be better 7004 than the default optimization level -O0. 7005 * A new option -ftree-partial-pre was added to control the partial 7006 redundancy elimination (PRE) optimization. This option is enabled 7007 by default at the -O3 optimization level, and it makes PRE more 7008 aggressive. 7009 * The option -fconserve-space has been removed; it was no longer 7010 useful on most targets since GCC supports putting variables into 7011 BSS without making them common. 7012 * The struct reorg and matrix reorg optimizations (command-line 7013 options -fipa-struct-reorg and -fipa-matrix-reorg) have been 7014 removed. They did not always work correctly, nor did they work with 7015 link-time optimization (LTO), hence were only applicable to 7016 programs consisting of a single translation unit. 7017 * Several scalability bottle-necks have been removed from GCC's 7018 optimization passes. Compilation of extremely large functions, e.g. 7019 due to the use of the flatten attribute in the "Eigen" C++ linear 7020 algebra templates library, is significantly faster than previous 7021 releases of GCC. 7022 * Link-time optimization (LTO) improvements: 7023 + LTO partitioning has been rewritten for better reliability and 7024 maintanibility. Several important bugs leading to link 7025 failures have been fixed. 7026 * Interprocedural optimization improvements: 7027 + A new symbol table has been implemented. It builds on existing 7028 callgraph and varpool modules and provide a new API. Unusual 7029 symbol visibilities and aliases are handled more consistently 7030 leading to, for example, more aggressive unreachable code 7031 removal with LTO. 7032 + The inline heuristic can now bypass limits on the size of of 7033 inlined functions when the inlining is particularly 7034 profitable. This happens, for example, when loop bounds or 7035 array strides get propagated. 7036 + Values passed through aggregates (either by value or 7037 reference) are now propagated at the inter-procedural level 7038 leading to better inlining decisions (for example in the case 7039 of Fortran array descriptors) and devirtualization. 7040 * [6]AddressSanitizer , a fast memory error detector, has been added 7041 and can be enabled via -fsanitize=address. Memory access 7042 instructions will be instrumented to detect heap-, stack-, and 7043 global-buffer overflow as well as use-after-free bugs. To get nicer 7044 stacktraces, use -fno-omit-frame-pointer. The AddressSanitizer is 7045 available on IA-32/x86-64/x32/PowerPC/PowerPC64 GNU/Linux and on 7046 x86-64 Darwin. 7047 * [7]ThreadSanitizer has been added and can be enabled via 7048 -fsanitize=thread. Instructions will be instrumented to detect data 7049 races. The ThreadSanitizer is available on x86-64 GNU/Linux. 7050 * A new local register allocator (LRA) has been implemented, which 7051 replaces the 26 year old reload pass and improves generated code 7052 quality. For now it is active on the IA-32 and x86-64 targets. 7053 * Support for transactional memory has been implemented on the 7054 following architectures: IA-32/x86-64, ARM, PowerPC, SH, SPARC, and 7055 Alpha. 7056 7057 New Languages and Language specific improvements 7058 7059 C family 7060 7061 * Each diagnostic emitted now includes the original source line and a 7062 caret '^' indicating the column. The option 7063 -fno-diagnostics-show-caret suppresses this information. 7064 * The option -ftrack-macro-expansion=2 is now enabled by default. 7065 This allows the compiler to display the macro expansion stack in 7066 diagnostics. Combined with the caret information, an example 7067 diagnostic showing these two features is: 7068 7069 t.c:1:94: error: invalid operands to binary < (have `struct mystruct' and `float 7070 ') 7071 #define MYMAX(A,B) __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) _ 7072 _b = (B); __a < __b ? __b : __a; }) 7073 7074 ^ 7075 t.c:7:7: note: in expansion of macro 'MYMAX' 7076 X = MYMAX(P, F); 7077 ^ 7078 7079 * A new -Wsizeof-pointer-memaccess warning has been added (also 7080 enabled by -Wall) to warn about suspicious length parameters to 7081 certain string and memory built-in functions if the argument uses 7082 sizeof. This warning warns e.g. about memset (ptr, 0, sizeof 7083 (ptr)); if ptr is not an array, but a pointer, and suggests a 7084 possible fix, or about memcpy (&foo, ptr, sizeof (&foo));. 7085 * The new option -Wpedantic is an alias for -pedantic, which is now 7086 deprecated. The forms -Wno-pedantic, -Werror=pedantic, and 7087 -Wno-error=pedantic work in the same way as for any other -W 7088 option. One caveat is that -Werror=pedantic is not equivalent to 7089 -pedantic-errors, since the latter makes into errors some warnings 7090 that are not controlled by -Wpedantic, and the former only affects 7091 diagnostics that are disabled when using -Wno-pedantic. 7092 * The option -Wshadow no longer warns if a declaration shadows a 7093 function declaration, unless the former declares a function or 7094 pointer to function, because this is [8]a common and valid case in 7095 real-world code. 7096 7097 C++ 7098 7099 * G++ now implements the [9]C++11 thread_local keyword; this differs 7100 from the GNU __thread keyword primarily in that it allows dynamic 7101 initialization and destruction semantics. Unfortunately, this 7102 support requires a run-time penalty for references to 7103 non-function-local thread_local variables defined in a different 7104 translation unit even if they don't need dynamic initialization, so 7105 users may want to continue to use __thread for TLS variables with 7106 static initialization semantics. 7107 If the programmer can be sure that no use of the variable in a 7108 non-defining TU needs to trigger dynamic initialization (either 7109 because the variable is statically initialized, or a use of the 7110 variable in the defining TU will be executed before any uses in 7111 another TU), they can avoid this overhead with the 7112 -fno-extern-tls-init option. 7113 OpenMP threadprivate variables now also support dynamic 7114 initialization and destruction by the same mechanism. 7115 * G++ now implements the [10]C++11 attribute syntax, e.g. 7116 7117 [[noreturn]] void f(); 7118 7119 and also the alignment specifier, e.g. 7120 7121 alignas(double) int i; 7122 7123 * G++ now implements [11]C++11 inheriting constructors, e.g. 7124 7125 struct A { A(int); }; 7126 struct B: A { using A::A; }; // defines B::B(int) 7127 B b(42); // OK 7128 7129 * As of GCC 4.8.1, G++ implements the change to decltype semantics 7130 from [12]N3276. 7131 7132 struct A f(); 7133 decltype(f()) g(); // OK, return type of f() is not required to be complete. 7134 7135 * As of GCC 4.8.1, G++ implements [13]C++11 ref-qualifiers, e.g. 7136 7137 struct A { int f() &; }; 7138 int i = A().f(); // error, f() requires an lvalue object 7139 7140 * G++ now supports a -std=c++1y option for experimentation with 7141 features proposed for the next revision of the standard, expected 7142 around 2014. Currently the only difference from -std=c++11 is 7143 support for return type deduction in normal functions, as proposed 7144 in [14]N3386. Status of C++1y features in GCC 4.8 can be found 7145 [15]here. 7146 * The G++ namespace association extension, __attribute ((strong)), 7147 has been deprecated. Inline namespaces should be used instead. 7148 * G++ now supports a -fext-numeric-literal option to control whether 7149 GNU numeric literal suffixes are accepted as extensions or 7150 processed as C++11 user-defined numeric literal suffixes. The flag 7151 is on (use suffixes for GNU literals) by default for -std=gnu++*, 7152 and -std=c++98. The flag is off (use suffixes for user-defined 7153 literals) by default for -std=c++11 and later. 7154 7155 Runtime Library (libstdc++) 7156 7157 * [16]Improved experimental support for the new ISO C++ standard, 7158 C++11, including: 7159 + forward_list meets the allocator-aware container requirements; 7160 + this_thread::sleep_for(), this_thread::sleep_until() and 7161 this_thread::yield() are defined without requiring the 7162 configure option --enable-libstdcxx-time; 7163 * Improvements to <random>: 7164 + SSE optimized normal_distribution. 7165 + Use of hardware RNG instruction for random_device on new x86 7166 processors (requires the assembler to support the 7167 instruction.) 7168 and <ext/random>: 7169 + New random number engine simd_fast_mersenne_twister_engine 7170 with an optimized SSE implementation. 7171 + New random number distributions beta_distribution, 7172 normal_mv_distribution, rice_distribution, 7173 nakagami_distribution, pareto_distribution, k_distribution, 7174 arcsine_distribution, hoyt_distribution. 7175 * Added --disable-libstdcxx-verbose configure option to disable 7176 diagnostic messages issued when a process terminates abnormally. 7177 This may be useful for embedded systems to reduce the size of 7178 executables that link statically to the library. 7179 7180 Fortran 7181 7182 * Compatibility notice: 7183 + Module files: The version of module files (.mod) has been 7184 incremented. Fortran MODULEs compiled by earlier GCC versions 7185 have to be recompiled, when they are USEd by files compiled 7186 with GCC 4.8. GCC 4.8 is not able to read .mod files created 7187 by earlier versions; attempting to do so gives an error 7188 message. 7189 Note: The ABI of the produced assembler data itself has not 7190 changed; object files and libraries are fully compatible with 7191 older versions except as noted below. 7192 + ABI: Some internal names (used in the assembler/object file) 7193 have changed for symbols declared in the specification part of 7194 a module. If an affected module - or a file using it via use 7195 association - is recompiled, the module and all files which 7196 directly use such symbols have to be recompiled as well. This 7197 change only affects the following kind of module symbols: 7198 o Procedure pointers. Note: C-interoperable function 7199 pointers (type(c_funptr)) are not affected nor are 7200 procedure-pointer components. 7201 o Deferred-length character strings. 7202 * The [17]BACKTRACE intrinsic subroutine has been added. It shows a 7203 backtrace at an arbitrary place in user code; program execution 7204 continues normally afterwards. 7205 * The [18]-Wc-binding-type warning option has been added (disabled by 7206 default). It warns if the a variable might not be C interoperable; 7207 in particular, if the variable has been declared using an intrinsic 7208 type with default kind instead of using a kind parameter defined 7209 for C interoperability in the intrinsic ISO_C_Binding module. 7210 Before, this warning was always printed. The -Wc-binding-type 7211 option is enabled by -Wall. 7212 * The [19]-Wrealloc-lhs and -Wrealloc-lhs-all warning command-line 7213 options have been added, which diagnose when code is inserted for 7214 automatic (re)allocation of a variable during assignment. This 7215 option can be used to decide whether it is safe to use 7216 [20]-fno-realloc-lhs. Additionally, it can be used to find 7217 automatic (re)allocation in hot loops. (For arrays, replacing 7218 "var=" by "var(:)=" disables the automatic reallocation.) 7219 * The [21]-Wcompare-reals command-line option has been added. When 7220 this is set, warnings are issued when comparing REAL or COMPLEX 7221 types for equality and inequality; consider replacing a == b by 7222 abs(a-b) < eps with a suitable eps. -Wcompare-reals is enabled by 7223 -Wextra. 7224 * The [22]-Wtarget-lifetime command-line option has been added 7225 (enabled with -Wall), which warns if the pointer in a pointer 7226 assignment might outlive its target. 7227 * Reading floating point numbers which use "q" for the exponential 7228 (such as 4.0q0) is now supported as vendor extension for better 7229 compatibility with old data files. It is strongly recommended to 7230 use for I/O the equivalent but standard conforming "e" (such as 7231 4.0e0). 7232 (For Fortran source code, consider replacing the "q" in 7233 floating-point literals by a kind parameter (e.g. 4.0e0_qp with a 7234 suitable qp). Note that - in Fortran source code - replacing "q" by 7235 a simple "e" is not equivalent.) 7236 * The GFORTRAN_TMPDIR environment variable for specifying a 7237 non-default directory for files opened with STATUS="SCRATCH", is 7238 not used anymore. Instead gfortran checks the POSIX/GNU standard 7239 TMPDIR environment variable. If TMPDIR is not defined, gfortran 7240 falls back to other methods to determine the directory for 7241 temporary files as documented in the [23]user manual. 7242 * [24]Fortran 2003: 7243 + Support for unlimited polymorphic variables (CLASS(*)) has 7244 been added. Nonconstant character lengths are not yet 7245 supported. 7246 * [25]TS 29113: 7247 + Assumed types (TYPE(*)) are now supported. 7248 + Experimental support for assumed-rank arrays (dimension(..)) 7249 has been added. Note that currently gfortran's own array 7250 descriptor is used, which is different from the one defined in 7251 TS29113, see [26]gfortran's header file or use the [27]Chasm 7252 Language Interoperability Tools. 7253 7254 Go 7255 7256 * GCC 4.8.2 provides a complete implementation of the Go 1.1.2 7257 release. 7258 * GCC 4.8.0 and 4.8.1 implement a preliminary version of the Go 1.1 7259 release. The library support is not quite complete. 7260 * Go has been tested on GNU/Linux and Solaris platforms for various 7261 processors including x86, x86_64, PowerPC, SPARC, and Alpha. It may 7262 work on other platforms as well. 7263 7264 New Targets and Target Specific Improvements 7265 7266 AArch64 7267 7268 * A new port has been added to support AArch64, the new 64-bit 7269 architecture from ARM. Note that this is a separate port from the 7270 existing 32-bit ARM port. 7271 * The port provides initial support for the Cortex-A53 and the 7272 Cortex-A57 processors with the command line options 7273 -mcpu=cortex-a53 and -mcpu=cortex-a57. 7274 * As of GCC 4.8.4 a workaround for the ARM Cortex-A53 erratum 835769 7275 has been added and can be enabled by giving the 7276 -mfix-cortex-a53-835769 option. Alternatively it can be enabled by 7277 default by configuring GCC with the --enable-fix-cortex-a53-835769 7278 option. 7279 7280 ARM 7281 7282 * Initial support has been added for the AArch32 extensions defined 7283 in the ARMv8 architecture. 7284 * Code generation improvements for the Cortex-A7 and Cortex-A15 CPUs. 7285 * A new option, -mcpu=marvell-pj4, has been added to generate code 7286 for the Marvell PJ4 processor. 7287 * The compiler can now automatically generate the VFMA, VFMS, REVSH 7288 and REV16 instructions. 7289 * A new vectorizer cost model for Advanced SIMD configurations to 7290 improve the auto-vectorization strategies used. 7291 * The scheduler now takes into account the number of live registers 7292 to reduce the amount of spilling that can occur. This should 7293 improve code performance in large functions. The limit can be 7294 removed by using the option -fno-sched-pressure. 7295 * Improvements have been made to the Marvell iWMMX code generation 7296 and support for the iWMMX2 SIMD unit has been added. The option 7297 -mcpu=iwmmxt2 can be used to enable code generation for the latter. 7298 * A number of code generation improvements for Thumb2 to reduce code 7299 size when compiling for the M-profile processors. 7300 * The RTEMS (arm-rtems) port has been updated to use the EABI. 7301 * Code generation support for the old FPA and Maverick floating-point 7302 architectures has been removed. Ports that previously relied on 7303 these features have also been removed. This includes the targets: 7304 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 7305 + arm*-*-elf (use arm*-*-eabi) 7306 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 7307 + arm*-*-ecos-elf (no alternative) 7308 + arm*-*-freebsd (no alternative) 7309 + arm*-wince-pe* (no alternative). 7310 7311 AVR 7312 7313 * Support for the "Embedded C" fixed-point has been added. For 7314 details, see the [28]GCC wiki and the [29]user manual. The support 7315 is not complete. 7316 * A new print modifier %r for register operands in inline assembler 7317 is supported. It will print the raw register number without the 7318 register prefix 'r': 7319 /* Return the most significant byte of 'val', a 64-bit value. */ 7320 7321 unsigned char msb (long long val) 7322 { 7323 unsigned char c; 7324 __asm__ ("mov %0, %r1+7" : "=r" (c) : "r" (val)); 7325 return c; 7326 } 7327 The inline assembler in this example will generate code like 7328 mov r24, 8+7 7329 provided c is allocated to R24 and val is allocated to R8...R15. 7330 This works because the GNU assembler accepts plain register numbers 7331 without register prefix. 7332 * Static initializers with 3-byte symbols are supported now: 7333 extern const __memx char foo; 7334 const __memx void *pfoo = &foo; 7335 This requires at least Binutils 2.23. 7336 7337 IA-32/x86-64 7338 7339 * Allow -mpreferred-stack-boundary=3 for the x86-64 architecture with 7340 SSE extensions disabled. Since the x86-64 ABI requires 16 byte 7341 stack alignment, this is ABI incompatible and intended to be used 7342 in controlled environments where stack space is an important 7343 limitation. This option will lead to wrong code when functions 7344 compiled with 16 byte stack alignment (such as functions from a 7345 standard library) are called with misaligned stack. In this case, 7346 SSE instructions may lead to misaligned memory access traps. In 7347 addition, variable arguments will be handled incorrectly for 16 7348 byte aligned objects (including x87 long double and __int128), 7349 leading to wrong results. You must build all modules with 7350 -mpreferred-stack-boundary=3, including any libraries. This 7351 includes the system libraries and startup modules. 7352 * Support for the new Intel processor codename Broadwell with RDSEED, 7353 ADCX, ADOX, PREFETCHW is available through -madx, -mprfchw, 7354 -mrdseed command-line options. 7355 * Support for the Intel RTM and HLE intrinsics, built-in functions 7356 and code generation is available via -mrtm and -mhle. 7357 * Support for the Intel FXSR, XSAVE and XSAVEOPT instruction sets. 7358 Intrinsics and built-in functions are available via -mfxsr, -mxsave 7359 and -mxsaveopt respectively. 7360 * New -maddress-mode=[short|long] options for x32. 7361 -maddress-mode=short overrides default 64-bit addresses to 32-bit 7362 by emitting the 0x67 address-size override prefix. This is the 7363 default address mode for x32. 7364 * New built-in functions to detect run-time CPU type and ISA: 7365 + A built-in function __builtin_cpu_is has been added to detect 7366 if the run-time CPU is of a particular type. It returns a 7367 positive integer on a match and zero otherwise. It accepts one 7368 string literal argument, the CPU name. For example, 7369 __builtin_cpu_is("westmere") returns a positive integer if the 7370 run-time CPU is an Intel Core i7 Westmere processor. Please 7371 refer to the [30]user manual for the list of valid CPU names 7372 recognized. 7373 + A built-in function __builtin_cpu_supports has been added to 7374 detect if the run-time CPU supports a particular ISA feature. 7375 It returns a positive integer on a match and zero otherwise. 7376 It accepts one string literal argument, the ISA feature. For 7377 example, __builtin_cpu_supports("ssse3") returns a positive 7378 integer if the run-time CPU supports SSSE3 instructions. 7379 Please refer to the [31]user manual for the list of valid ISA 7380 names recognized. 7381 Caveat: If these built-in functions are called before any static 7382 constructors are invoked, like during IFUNC initialization, then 7383 the CPU detection initialization must be explicitly run using this 7384 newly provided built-in function, __builtin_cpu_init. The 7385 initialization needs to be done only once. For example, this is how 7386 the invocation would look like inside an IFUNC initializer: 7387 static void (*some_ifunc_resolver(void))(void) 7388 { 7389 __builtin_cpu_init(); 7390 if (__builtin_cpu_is("amdfam10h") ... 7391 if (__builtin_cpu_supports("popcnt") ... 7392 } 7393 7394 * Function Multiversioning Support with G++: 7395 It is now possible to create multiple function versions each 7396 targeting a specific processor and/or ISA. Function versions have 7397 the same signature but different target attributes. For example, 7398 here is a program with function versions: 7399 __attribute__ ((target ("default"))) 7400 int foo(void) 7401 { 7402 return 1; 7403 } 7404 7405 __attribute__ ((target ("sse4.2"))) 7406 int foo(void) 7407 { 7408 return 2; 7409 } 7410 7411 int main (void) 7412 { 7413 int (*p) = &foo; 7414 assert ((*p)() == foo()); 7415 return 0; 7416 } 7417 7418 Please refer to this [32]wiki for more information. 7419 * The x86 back end has been improved to allow option -fschedule-insns 7420 to work reliably. This option can be used to schedule instructions 7421 better and leads to improved performace in certain cases. 7422 * Windows MinGW-w64 targets (*-w64-mingw*) require at least r5437 7423 from the Mingw-w64 trunk. 7424 * Support for new AMD family 15h processors (Steamroller core) is now 7425 available through the -march=bdver3 and -mtune=bdver3 options. 7426 * Support for new AMD family 16h processors (Jaguar core) is now 7427 available through the -march=btver2 and -mtune=btver2 options. 7428 7429 FRV 7430 7431 * This target now supports the -fstack-usage command-line option. 7432 7433 MIPS 7434 7435 * GCC can now generate code specifically for the R4700, Broadcom XLP 7436 and MIPS 34kn processors. The associated -march options are 7437 -march=r4700, -march=xlp and -march=34kn respectively. 7438 * GCC now generates better DSP code for MIPS 74k cores thanks to 7439 further scheduling optimizations. 7440 * The MIPS port now supports the -fstack-check option. 7441 * GCC now passes the -mmcu and -mno-mcu options to the assembler. 7442 * Previous versions of GCC would silently accept -fpic and -fPIC for 7443 -mno-abicalls targets like mips*-elf. This combination was not 7444 intended or supported, and did not generate position-independent 7445 code. GCC 4.8 now reports an error when this combination is used. 7446 7447 PowerPC / PowerPC64 / RS6000 7448 7449 * SVR4 configurations (GNU/Linux, FreeBSD, NetBSD) no longer save, 7450 restore or update the VRSAVE register by default. The respective 7451 operating systems manage the VRSAVE register directly. 7452 * Large TOC support has been added for AIX through the command line 7453 option -mcmodel=large. 7454 * Native Thread-Local Storage support has been added for AIX. 7455 * VMX (Altivec) and VSX instruction sets now are enabled implicitly 7456 when targetting processors that support those hardware features on 7457 AIX 6.1 and above. 7458 7459 RX 7460 7461 * This target will now issue a warning message whenever multiple fast 7462 interrupt handlers are found in the same compilation unit. This 7463 feature can be turned off by the new 7464 -mno-warn-multiple-fast-interrupts command-line option. 7465 7466 S/390, System z 7467 7468 * Support for the IBM zEnterprise zEC12 processor has been added. 7469 When using the -march=zEC12 option, the compiler will generate code 7470 making use of the following new instructions: 7471 + load and trap instructions 7472 + 2 new compare and trap instructions 7473 + rotate and insert selected bits - without CC clobber 7474 The -mtune=zEC12 option enables zEC12 specific instruction 7475 scheduling without making use of new instructions. 7476 * Register pressure sensitive instruction scheduling is enabled by 7477 default. 7478 * The ifunc function attribute is enabled by default. 7479 * memcpy and memcmp invokations on big memory chunks or with run time 7480 lengths are not generated inline anymore when tuning for z10 or 7481 higher. The purpose is to make use of the IFUNC optimized versions 7482 in Glibc. 7483 7484 SH 7485 7486 * The default alignment settings have been reduced to be less 7487 aggressive. This results in more compact code for optimization 7488 levels other than -Os. 7489 * Improved support for the __atomic built-in functions: 7490 + A new option -matomic-model=model selects the model for the 7491 generated atomic sequences. The following models are 7492 supported: 7493 7494 soft-gusa 7495 Software gUSA sequences (SH3* and SH4* only). On 7496 SH4A targets this will now also partially utilize 7497 the movco.l and movli.l instructions. This is the 7498 default when the target is sh3*-*-linux* or 7499 sh4*-*-linux*. 7500 7501 hard-llcs 7502 Hardware movco.l / movli.l sequences (SH4A only). 7503 7504 soft-tcb 7505 Software thread control block sequences. 7506 7507 soft-imask 7508 Software interrupt flipping sequences (privileged 7509 mode only). This is the default when the target is 7510 sh1*-*-linux* or sh2*-*-linux*. 7511 7512 none 7513 Generates function calls to the respective __atomic 7514 built-in functions. This is the default for SH64 7515 targets or when the target is not sh*-*-linux*. 7516 7517 + The option -msoft-atomic has been deprecated. It is now an 7518 alias for -matomic-model=soft-gusa. 7519 + A new option -mtas makes the compiler generate the tas.b 7520 instruction for the __atomic_test_and_set built-in function 7521 regardless of the selected atomic model. 7522 + The __sync functions in libgcc now reflect the selected atomic 7523 model when building the toolchain. 7524 * Added support for the mov.b and mov.w instructions with 7525 displacement addressing. 7526 * Added support for the SH2A instructions movu.b and movu.w. 7527 * Various improvements to code generated for integer arithmetic. 7528 * Improvements to conditional branches and code that involves the T 7529 bit. A new option -mzdcbranch tells the compiler to favor 7530 zero-displacement branches. This is enabled by default for SH4* 7531 targets. 7532 * The pref instruction will now be emitted by the __builtin_prefetch 7533 built-in function for SH3* targets. 7534 * The fmac instruction will now be emitted by the fmaf standard 7535 function and the __builtin_fmaf built-in function. 7536 * The -mfused-madd option has been deprecated in favor of the 7537 machine-independent -ffp-contract option. Notice that the fmac 7538 instruction will now be generated by default for expressions like a 7539 * b + c. This is due to the compiler default setting 7540 -ffp-contract=fast. 7541 * Added new options -mfsrra and -mfsca to allow the compiler using 7542 the fsrra and fsca instructions on targets other than SH4A (where 7543 they are already enabled by default). 7544 * Added support for the __builtin_bswap32 built-in function. It is 7545 now expanded as a sequence of swap.b and swap.w instructions 7546 instead of a library function call. 7547 * The behavior of the -mieee option has been fixed and the negative 7548 form -mno-ieee has been added to control the IEEE conformance of 7549 floating point comparisons. By default -mieee is now enabled and 7550 the option -ffinite-math-only implicitly sets -mno-ieee. 7551 * Added support for the built-in functions __builtin_thread_pointer 7552 and __builtin_set_thread_pointer. This assumes that GBR is used to 7553 hold the thread pointer of the current thread. Memory loads and 7554 stores relative to the address returned by __builtin_thread_pointer 7555 will now also utilize GBR based displacement address modes. 7556 * The -mdiv= option for targets other than SHmedia has been fixed and 7557 documented. 7558 7559 SPARC 7560 7561 * Added optimized instruction scheduling for Niagara4. 7562 7563 TILE-Gx 7564 7565 * Added support for the -mcmodel=MODEL command-line option. The 7566 models supported are small and large. 7567 7568 V850 7569 7570 * This target now supports the E3V5 architecture via the use of the 7571 new -mv850e3v5 command-line option. It also has experimental 7572 support for the e3v5 LOOP instruction which can be enabled via the 7573 new -mloop command-line option. 7574 7575 XStormy16 7576 7577 * This target now supports the -fstack-usage command-line option. 7578 7579 Operating Systems 7580 7581 OpenBSD 7582 7583 * Support for OpenBSD/amd64 (x86_64-*-openbsd*) has been added and 7584 support for OpenBSD/i386 (i386-*-openbsd*) has been rejuvenated. 7585 7586 Windows (Cygwin) 7587 7588 * Executables are now linked against shared libgcc by default. The 7589 previous default was to link statically, which can still be done by 7590 explicitly specifying -static or static-libgcc on the command line. 7591 However it is strongly advised against, as it will cause problems 7592 for any application that makes use of DLLs compiled by GCC. It 7593 should be alright for a monolithic stand-alone application that 7594 only links against the Windows DLLs, but offers little or no 7595 benefit. 7596 7597 GCC 4.8.1 7598 7599 This is the [33]list of problem reports (PRs) from GCC's bug tracking 7600 system that are known to be fixed in the 4.8.1 release. This list might 7601 not be complete (that is, it is possible that some PRs that have been 7602 fixed are not listed here). 7603 7604 The C++11 <chrono> std::chrono::system_clock and 7605 std::chrono::steady_clock classes have changed ABI in GCC 4.8.1, they 7606 both are now separate (never typedefs of each other), both use 7607 std::chrono::nanoseconds resolution, on most GNU/Linux configurations 7608 std::chrono::steady_clock is now finally monotonic, and both classes 7609 are mangled differently than in the previous GCC releases. 7610 std::chrono::system_clock::now() with std::chrono::microseconds resp. 7611 std::chrono::seconds resolution is still exported for backwards 7612 compatibility with default configured libstdc++. Note that libstdc++ 7613 configured with --enable-libstdcxx-time= used to be ABI incompatible 7614 with default configured libstdc++ for those two classes and no ABI 7615 compatibility can be offered for those configurations, so any C++11 7616 code that uses those classes and has been compiled and linked against 7617 libstdc++ configured with the non-default --enable-libstdcxx-time= 7618 configuration option needs to be recompiled. 7619 7620 GCC 4.8.2 7621 7622 This is the [34]list of problem reports (PRs) from GCC's bug tracking 7623 system that are known to be fixed in the 4.8.2 release. This list might 7624 not be complete (that is, it is possible that some PRs that have been 7625 fixed are not listed here). 7626 7627 GCC 4.8.3 7628 7629 This is the [35]list of problem reports (PRs) from GCC's bug tracking 7630 system that are known to be fixed in the 4.8.3 release. This list might 7631 not be complete (that is, it is possible that some PRs that have been 7632 fixed are not listed here). 7633 7634 Support for the new powerpc64le-linux platform has been added. It 7635 defaults to generating code that conforms to the ELFV2 ABI. 7636 7637 GCC 4.8.4 7638 7639 This is the [36]list of problem reports (PRs) from GCC's bug tracking 7640 system that are known to be fixed in the 4.8.4 release. This list might 7641 not be complete (that is, it is possible that some PRs that have been 7642 fixed are not listed here). 7643 7644 GCC 4.8.5 7645 7646 This is the [37]list of problem reports (PRs) from GCC's bug tracking 7647 system that are known to be fixed in the 4.8.5 release. This list might 7648 not be complete (that is, it is possible that some PRs that have been 7649 fixed are not listed here). 7650 7651 7652 For questions related to the use of GCC, please consult these web 7653 pages and the [38]GCC manuals. If that fails, the 7654 [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 7655 web pages and the development of GCC are welcome on our developer 7656 list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public 7657 archives. 7658 7659 Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and 7660 distribution of this entire article is permitted in any medium, 7661 provided this notice is preserved. 7662 7663 These pages are [43]maintained by the GCC team. Last modified 7664 2020-03-26[44]. 7665 7666 References 7667 7668 1. https://gcc.gnu.org/wiki/cxx-conversion 7669 2. ftp://gcc.gnu.org/pub/gcc/infrastructure/ 7670 3. http://www.nongnu.org/avr-libc/ 7671 4. https://gcc.gnu.org/PR54461 7672 5. https://gcc.gnu.org/gcc-4.8/porting_to.html 7673 6. https://github.com/google/sanitizers 7674 7. https://code.google.com/archive/p/data-race-test/wikis/ThreadSanitizer.wiki 7675 8. https://lkml.org/lkml/2006/11/28/239 7676 9. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7677 10. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7678 11. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7679 12. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3276.pdf 7680 13. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html 7681 14. http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3386.html 7682 15. http://gcc.gnu.org/projects/cxx1y.html 7683 16. https://gcc.gnu.org/onlinedocs/gcc-4.8.4/libstdc++/manual/manual/status.html#status.iso.2011 7684 17. https://gcc.gnu.org/onlinedocs/gfortran/BACKTRACE.html 7685 18. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7686 19. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7687 20. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 7688 21. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7689 22. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html 7690 23. https://gcc.gnu.org/onlinedocs/gfortran/TMPDIR.html 7691 24. https://gcc.gnu.org/wiki/Fortran2003Status 7692 25. https://gcc.gnu.org/wiki/TS29113Status 7693 26. https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libgfortran/libgfortran.h 7694 27. http://chasm-interop.sourceforge.net/ 7695 28. https://gcc.gnu.org/wiki/avr-gcc#Fixed-Point_Support 7696 29. https://gcc.gnu.org/onlinedocs/gcc/Fixed-Point.html 7697 30. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 7698 31. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html 7699 32. https://gcc.gnu.org/wiki/FunctionMultiVersioning 7700 33. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.1 7701 34. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.2 7702 35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.3 7703 36. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.4 7704 37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.5 7705 38. https://gcc.gnu.org/onlinedocs/ 7706 39. mailto:gcc-help (a] gcc.gnu.org 7707 40. mailto:gcc (a] gcc.gnu.org 7708 41. https://gcc.gnu.org/lists.html 7709 42. https://www.fsf.org/ 7710 43. https://gcc.gnu.org/about.html 7711 44. http://validator.w3.org/check/referer 7712 ====================================================================== 7713 http://gcc.gnu.org/gcc-4.7/index.html 7714 7715 GCC 4.7 Release Series 7716 7717 (This release series is no longer supported.) 7718 7719 June 12, 2014 7720 7721 The [1]GNU project and the GCC developers are pleased to announce the 7722 release of GCC 4.7.4. 7723 7724 This release is a bug-fix release, containing fixes for regressions in 7725 GCC 4.7.3 relative to previous releases of GCC. 7726 7727 Release History 7728 7729 GCC 4.7.4 7730 June 12, 2014 ([2]changes, [3]documentation) 7731 7732 GCC 4.7.3 7733 April 11, 2013 ([4]changes, [5]documentation) 7734 7735 GCC 4.7.2 7736 September 20, 2012 ([6]changes, [7]documentation) 7737 7738 GCC 4.7.1 7739 June 14, 2012 ([8]changes, [9]documentation) 7740 7741 GCC 4.7.0 7742 March 22, 2012 ([10]changes, [11]documentation) 7743 7744 References and Acknowledgements 7745 7746 GCC used to stand for the GNU C Compiler, but since the compiler 7747 supports several other languages aside from C, it now stands for the 7748 GNU Compiler Collection. 7749 7750 A list of [12]successful builds is updated as new information becomes 7751 available. 7752 7753 The GCC developers would like to thank the numerous people that have 7754 contributed new features, improvements, bug fixes, and other changes as 7755 well as test results to GCC. This [13]amazing group of volunteers is 7756 what makes GCC successful. 7757 7758 For additional information about GCC please refer to the [14]GCC 7759 project web site or contact the [15]GCC development mailing list. 7760 7761 To obtain GCC please use [16]our mirror sites or [17]our version 7762 control system. 7763 7764 7765 For questions related to the use of GCC, please consult these web 7766 pages and the [18]GCC manuals. If that fails, the 7767 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 7768 web pages and the development of GCC are welcome on our developer 7769 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 7770 archives. 7771 7772 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 7773 distribution of this entire article is permitted in any medium, 7774 provided this notice is preserved. 7775 7776 These pages are [23]maintained by the GCC team. Last modified 7777 2020-01-14[24]. 7778 7779 References 7780 7781 1. http://www.gnu.org/ 7782 2. http://gcc.gnu.org/gcc-4.7/changes.html 7783 3. https://gcc.gnu.org/onlinedocs/4.7.4/ 7784 4. http://gcc.gnu.org/gcc-4.7/changes.html 7785 5. https://gcc.gnu.org/onlinedocs/4.7.3/ 7786 6. http://gcc.gnu.org/gcc-4.7/changes.html 7787 7. https://gcc.gnu.org/onlinedocs/4.7.2/ 7788 8. http://gcc.gnu.org/gcc-4.7/changes.html 7789 9. https://gcc.gnu.org/onlinedocs/4.7.1/ 7790 10. http://gcc.gnu.org/gcc-4.7/changes.html 7791 11. https://gcc.gnu.org/onlinedocs/4.7.0/ 7792 12. http://gcc.gnu.org/gcc-4.7/buildstat.html 7793 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 7794 14. http://gcc.gnu.org/index.html 7795 15. mailto:gcc (a] gcc.gnu.org 7796 16. http://gcc.gnu.org/mirrors.html 7797 17. http://gcc.gnu.org/git.html 7798 18. https://gcc.gnu.org/onlinedocs/ 7799 19. mailto:gcc-help (a] gcc.gnu.org 7800 20. mailto:gcc (a] gcc.gnu.org 7801 21. https://gcc.gnu.org/lists.html 7802 22. https://www.fsf.org/ 7803 23. https://gcc.gnu.org/about.html 7804 24. http://validator.w3.org/check/referer 7805 ====================================================================== 7806 http://gcc.gnu.org/gcc-4.7/changes.html 7807 7808 GCC 4.7 Release Series 7809 Changes, New Features, and Fixes 7810 7811 Caveats 7812 7813 * The -fconserve-space flag has been deprecated. The flag had no 7814 effect for most targets: only targets without a global .bss section 7815 and without support for switchable sections. Furthermore, the flag 7816 only had an effect for G++, where it could result in wrong 7817 semantics (please refer to the GCC manual for further details). The 7818 flag will be removed in GCC 4.8 7819 * Support for a number of older systems and recently unmaintained or 7820 untested target ports of GCC has been declared obsolete in GCC 4.7. 7821 Unless there is activity to revive them, the next release of GCC 7822 will have their sources permanently removed. 7823 All GCC ports for the following processor architectures have been 7824 declared obsolete: 7825 + picoChip (picochip-*) 7826 The following ports for individual systems on particular 7827 architectures have been obsoleted: 7828 + IRIX 6.5 (mips-sgi-irix6.5) 7829 + MIPS OpenBSD (mips*-*-openbsd*) 7830 + Solaris 8 (*-*-solaris2.8). Details can be found in the 7831 [1]announcement. 7832 + Tru64 UNIX V5.1 (alpha*-dec-osf5.1*) 7833 * On ARM, when compiling for ARMv6 (but not ARMv6-M), ARMv7-A, 7834 ARMv7-R, or ARMv7-M, the new option -munaligned-access is active by 7835 default, which for some sources generates code that accesses memory 7836 on unaligned addresses. This requires the kernel of those systems 7837 to enable such accesses (controlled by CP15 register c1, refer to 7838 ARM documentation). Alternatively, or for compatibility with 7839 kernels where unaligned accesses are not supported, all code has to 7840 be compiled with -mno-unaligned-access. Upstream Linux kernel 7841 releases have automatically and unconditionally supported unaligned 7842 accesses as emitted by GCC due to this option being active since 7843 version 2.6.28. 7844 * Support on ARM for the legacy floating-point accelerator (FPA) and 7845 the mixed-endian floating-point format that it used has been 7846 obsoleted. The ports that still use this format have been obsoleted 7847 as well. Many legacy ARM ports already provide an alternative that 7848 uses the VFP floating-point format. The obsolete ports will be 7849 deleted in the next release. 7850 The obsolete ports with alternatives are: 7851 + arm*-*-rtems (use arm*-*-rtemseabi) 7852 + arm*-*-linux-gnu (use arm*-*-linux-gnueabi) 7853 + arm*-*-elf (use arm*-*-eabi) 7854 + arm*-*-uclinux* (use arm*-*-uclinux*eabi) 7855 Note, however, that these alternatives are not binary compatible 7856 with their legacy counterparts (although some can support running 7857 legacy applications). 7858 The obsolete ports that currently lack a modern alternative are: 7859 + arm*-*-ecos-elf 7860 + arm*-*-freebsd 7861 + arm*-wince-pe* 7862 New ports that support more recent versions of the architecture are 7863 welcome. 7864 * Support for the Maverick co-processor on ARM has been obsoleted. 7865 Code to support it will be deleted in the next release. 7866 * Support has been removed for Unix International threads on Solaris 7867 2, so the --enable-threads=solaris configure option and the 7868 -threads compiler option don't work any longer. 7869 * Support has been removed for the Solaris BSD Compatibility Package, 7870 which lives in /usr/ucbinclude and /usr/ucblib. It has been removed 7871 from Solaris 11, and was only intended as a migration aid from 7872 SunOS 4 to SunOS 5. The -compat-bsd compiler option is not 7873 recognized any longer. 7874 * The AVR port's libgcc has been improved and its multilib structure 7875 has been enhanced. As a result, all objects contributing to an 7876 application must either be compiled with GCC versions up to 4.6.x 7877 or with GCC versions 4.7.1 or later. If the compiler is used with 7878 AVR Libc, you need a version that supports the new layout, i.e. 7879 implements [2]#35407. 7880 * The AVR port's -mshort-calls command-line option has been 7881 deprecated. It will be removed in the GCC 4.8 release. See -mrelax 7882 for a replacement. 7883 * The AVR port only references startup code that clears .bss and the 7884 common section resp. initializes the .data and .rodata section 7885 provided respective sections (or subsections thereof) are not 7886 empty, see [3]PR18145. Applications that put all static storage 7887 objects into non-standard sections and / or define all static 7888 storage objects in assembler modules, must reference __do_clear_bss 7889 resp. __do_copy_data by hand or undefine the symbol(s) by means of 7890 -Wl,-u,__do_clear_bss resp. -Wl,-u,__do_copy_data. 7891 * The ARM port's -mwords-little-endian option has been deprecated. It 7892 will be removed in a future release. 7893 * Support has been removed for the NetWare x86 configuration 7894 obsoleted in GCC 4.6. 7895 * It is no longer possible to use the "l" constraint in MIPS16 asm 7896 statements. 7897 * GCC versions 4.7.0 and 4.7.1 had changes to the C++ standard 7898 library which affected the ABI in C++11 mode: a data member was 7899 added to std::list changing its size and altering the definitions 7900 of some member functions, and std::pair's move constructor was 7901 non-trivial which altered the calling convention for functions with 7902 std::pair arguments or return types. The ABI incompatibilities have 7903 been fixed for GCC version 4.7.2 but as a result C++11 code 7904 compiled with GCC 4.7.0 or 4.7.1 may be incompatible with C++11 7905 code compiled with different GCC versions and with C++98/C++03 code 7906 compiled with any version. 7907 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 7908 rules for the layout of vectors that could lead to wrong code being 7909 generated. Vectors larger than 8 bytes in size are now by default 7910 aligned to an 8-byte boundary. This is an ABI change: code that 7911 makes explicit use of vector types may be incompatible with binary 7912 objects built with older versions of GCC. Auto-vectorized code is 7913 not affected by this change. (This change affects GCC versions 7914 4.7.2 and later.) 7915 * More information on porting to GCC 4.7 from previous versions of 7916 GCC can be found in the [4]porting guide for this release. 7917 7918 General Optimizer Improvements 7919 7920 * Support for a new parameter --param case-values-threshold=n was 7921 added to allow users to control the cutoff between doing switch 7922 statements as a series of if statements and using a jump table. 7923 * Link-time optimization (LTO) improvements: 7924 + Improved scalability and reduced memory usage. Link time 7925 optimization of Firefox now requires 3GB of RAM on a 64-bit 7926 system, while over 8GB was needed previously. Linking time has 7927 been improved, too. The serial stage of linking Firefox has 7928 been sped up by about a factor of 10. 7929 + Reduced size of object files and temporary storage used during 7930 linking. 7931 + Streaming performance (both outbound and inbound) has been 7932 improved. 7933 + ld -r is now supported with LTO. 7934 + Several bug fixes, especially in symbol table handling and 7935 merging. 7936 * Interprocedural optimization improvements: 7937 + Heuristics now take into account that after inlining code will 7938 be optimized out because of known values (or properties) of 7939 function parameters. For example: 7940 void foo(int a) 7941 { 7942 if (a > 10) 7943 ... huge code ... 7944 } 7945 void bar (void) 7946 { 7947 foo (0); 7948 } 7949 7950 The call of foo will be inlined into bar even when optimizing 7951 for code size. Constructs based on __builtin_constant_p are 7952 now understood by the inliner and code size estimates are 7953 evaluated a lot more realistically. 7954 + The representation of C++ virtual thunks and aliases (both 7955 implicit and defined via the alias attribute) has been 7956 re-engineered. Aliases no longer pose optimization barriers 7957 and calls to an alias can be inlined and otherwise optimized. 7958 + The inter-procedural constant propagation pass has been 7959 rewritten. It now performs generic function specialization. 7960 For example when compiling the following: 7961 void foo(bool flag) 7962 { 7963 if (flag) 7964 ... do something ... 7965 else 7966 ... do something else ... 7967 } 7968 void bar (void) 7969 { 7970 foo (false); 7971 foo (true); 7972 foo (false); 7973 foo (true); 7974 foo (false); 7975 foo (true); 7976 } 7977 7978 GCC will now produce two copies of foo. One with flag being 7979 true, while other with flag being false. This leads to 7980 performance improvements previously possible only by inlining 7981 all calls. Cloning causes a lot less code size growth. 7982 * A string length optimization pass has been added. It attempts to 7983 track string lengths and optimize various standard C string 7984 functions like strlen, strchr, strcpy, strcat, stpcpy and their 7985 _FORTIFY_SOURCE counterparts into faster alternatives. This pass is 7986 enabled by default at -O2 or above, unless optimizing for size, and 7987 can be disabled by the -fno-optimize-strlen option. The pass can 7988 e.g. optimize 7989 char *bar (const char *a) 7990 { 7991 size_t l = strlen (a) + 2; 7992 char *p = malloc (l); if (p == NULL) return p; 7993 strcpy (p, a); strcat (p, "/"); return p; 7994 } 7995 7996 into: 7997 char *bar (const char *a) 7998 { 7999 size_t tmp = strlen (a); 8000 char *p = malloc (tmp + 2); if (p == NULL) return p; 8001 memcpy (p, a, tmp); memcpy (p + tmp, "/", 2); return p; 8002 } 8003 8004 or for hosted compilations where stpcpy is available in the runtime 8005 and headers provide its prototype, e.g. 8006 void foo (char *a, const char *b, const char *c, const char *d) 8007 { 8008 strcpy (a, b); strcat (a, c); strcat (a, d); 8009 } 8010 8011 can be optimized into: 8012 void foo (char *a, const char *b, const char *c, const char *d) 8013 { 8014 strcpy (stpcpy (stpcpy (a, b), c), d); 8015 } 8016 8017 New Languages and Language specific improvements 8018 8019 * Version 3.1 of the OpenMP specification is now supported for the C, 8020 C++, and Fortran compilers. 8021 8022 Ada 8023 8024 * The command-line option -feliminate-unused-debug-types has been 8025 re-enabled by default, as it is for the other languages, leading to 8026 a reduction in debug info size of 12.5% and more for relevant 8027 cases, as well as to a small compilation speedup. 8028 8029 C family 8030 8031 * A new built-in, __builtin_assume_aligned, has been added, through 8032 which the compiler can be hinted about pointer alignment and can 8033 use it to improve generated code. 8034 * A new warning option -Wunused-local-typedefs was added for C, C++, 8035 Objective-C and Objective-C++. This warning diagnoses typedefs 8036 locally defined in a function, and otherwise not used. 8037 * A new experimental command-line option -ftrack-macro-expansion was 8038 added for C, C++, Objective-C, Objective-C++ and Fortran. It allows 8039 the compiler to emit diagnostic about the current macro expansion 8040 stack when a compilation error occurs in a macro expansion. 8041 * Experimental support for transactional memory has been added. It 8042 includes support in the compiler, as well as a supporting runtime 8043 library called libitm. To compile code with transactional memory 8044 constructs, use the -fgnu-tm option. 8045 Support is currently available for Alpha, ARM, PowerPC, SH, SPARC, 8046 and 32-bit/64-bit x86 platforms. 8047 For more details on transactional memory see [5]the GCC WiKi. 8048 * Support for atomic operations specifying the C++11/C11 memory model 8049 has been added. These new __atomic routines replace the existing 8050 __sync built-in routines. 8051 Atomic support is also available for memory blocks. Lock-free 8052 instructions will be used if a memory block is the same size and 8053 alignment as a supported integer type. Atomic operations which do 8054 not have lock-free support are left as function calls. A set of 8055 library functions is available on the GCC atomic wiki in the 8056 "External Atomics Library" section. 8057 For more details on the memory models and features, see the 8058 [6]atomic wiki. 8059 * When a binary operation is performed on vector types and one of the 8060 operands is a uniform vector, it is possible to replace the vector 8061 with the generating element. For example: 8062 typedef int v4si __attribute__ ((vector_size (16))); 8063 v4si res, a = {1,2,3,4}; 8064 int x; 8065 8066 res = 2 + a; /* means {2,2,2,2} + a */ 8067 res = a - x; /* means a - {x,x,x,x} */ 8068 8069 C 8070 8071 * There is support for some more features from the C11 revision of 8072 the ISO C standard. GCC now accepts the options -std=c11 and 8073 -std=gnu11, in addition to the previous -std=c1x and -std=gnu1x. 8074 + Unicode strings (previously supported only with options such 8075 as -std=gnu11, now supported with -std=c11), and the 8076 predefined macros __STDC_UTF_16__ and __STDC_UTF_32__. 8077 + Nonreturning functions (_Noreturn and <stdnoreturn.h>). 8078 + Alignment support (_Alignas, _Alignof, max_align_t, 8079 <stdalign.h>). 8080 + A built-in function __builtin_complex is provided to support C 8081 library implementation of the CMPLX family of macros. 8082 8083 C++ 8084 8085 * G++ now accepts the -std=c++11, -std=gnu++11, and -Wc++11-compat 8086 options, which are equivalent to -std=c++0x, -std=gnu++0x, and 8087 -Wc++0x-compat, respectively. 8088 * G++ now implements [7]C++11 extended friend syntax: 8089 8090 template<class W> 8091 class Q 8092 { 8093 static const int I = 2; 8094 public: 8095 friend W; 8096 }; 8097 8098 struct B 8099 { 8100 int ar[Q<B>::I]; 8101 }; 8102 8103 * Thanks to Ville Voutilainen, G++ now implements [8]C++11 explicit 8104 override control. 8105 8106 struct B { 8107 virtual void f() const final; 8108 virtual void f(int); 8109 }; 8110 8111 struct D : B { 8112 void f() const; // error: D::f attempts to override final B::f 8113 void f(long) override; // error: doesn't override anything 8114 void f(int) override; // ok 8115 }; 8116 8117 struct E final { }; 8118 struct F: E { }; // error: deriving from final class 8119 8120 * G++ now implements [9]C++11 non-static data member initializers. 8121 8122 struct A { 8123 int i = 42; 8124 } a; // initializes a.i to 42 8125 8126 * Thanks to Ed Smith-Rowland, G++ now implements [10]C++11 8127 user-defined literals. 8128 8129 // Not actually a good approximation. :) 8130 constexpr long double operator"" _degrees (long double d) { return d * 0.0175; } 8131 long double pi = 180.0_degrees; 8132 8133 * G++ now implements [11]C++11 alias-declarations. 8134 8135 template <class T> using Ptr = T*; 8136 Ptr<int> ip; // decltype(ip) is int* 8137 8138 * Thanks to Ville Voutilainen and Pedro Lamaro, G++ now implements 8139 [12]C++11 delegating constructors. 8140 8141 struct A { 8142 A(int); 8143 A(): A(42) { } // delegate to the A(int) constructor 8144 }; 8145 8146 * G++ now fully implements C++11 atomic classes rather than just 8147 integer derived classes. 8148 8149 class POD { 8150 int a; 8151 int b; 8152 }; 8153 std::atomic<POD> my_atomic_POD; 8154 8155 * G++ now sets the predefined macro __cplusplus to the correct value, 8156 199711L for C++98/03, and 201103L for C++11. 8157 * G++ now correctly implements the two-phase lookup rules such that 8158 an unqualified name used in a template must have an appropriate 8159 declaration found either in scope at the point of definition of the 8160 template or by argument-dependent lookup at the point of 8161 instantiation. As a result, code that relies on a second 8162 unqualified lookup at the point of instantiation to find functions 8163 declared after the template or in dependent bases will be rejected. 8164 The compiler will suggest ways to fix affected code, and using the 8165 -fpermissive compiler flag will allow the code to compile with a 8166 warning. 8167 8168 template <class T> 8169 void f() { g(T()); } // error, g(int) not found by argument-dependent lookup 8170 void g(int) { } // fix by moving this declaration before the declaration of f 8171 8172 template <class T> 8173 struct A: T { 8174 // error, B::g(B) not found by argument-dependent lookup 8175 void f() { g(T()); } // fix by using this->g or A::g 8176 }; 8177 8178 struct B { void g(B); }; 8179 8180 int main() 8181 { 8182 f<int>(); 8183 A<B>().f(); 8184 } 8185 8186 * G++ now properly re-uses stack space allocated for temporary 8187 objects when their lifetime ends, which can significantly lower 8188 stack consumption for some C++ functions. As a result of this, some 8189 code with undefined behavior will now break: 8190 8191 const int &f(const int &i) { return i; } 8192 .... 8193 const int &x = f(1); 8194 const int &y = f(2); 8195 8196 Here, x refers to the temporary allocated to hold the 1 argument, 8197 which only lives until the end of the initialization; it 8198 immediately becomes a dangling reference. So the next statement 8199 re-uses the stack slot to hold the 2 argument, and users of x get 8200 that value instead. 8201 Note that this should not cause any change of behavior for 8202 temporaries of types with non-trivial destructors, as they are 8203 already destroyed at end of full-expression; the change is that now 8204 the storage is released as well. 8205 * A new command-line option -Wdelete-non-virtual-dtor has been added 8206 to warn when delete is used to destroy an instance of a class which 8207 has virtual functions and non-virtual destructor. It is unsafe to 8208 delete an instance of a derived class through a pointer to a base 8209 class if the base class does not have a virtual destructor. This 8210 warning is enabled by -Wall. 8211 * A new command-line option -Wzero-as-null-pointer-constant has been 8212 added to warn when a literal '0' is used as null pointer constant. 8213 It can be useful to facilitate the conversion to nullptr in C++11. 8214 * As per C++98, access-declarations are now deprecated by G++. 8215 Using-declarations are to be used instead. Furthermore, some 8216 efforts have been made to improve the support of class scope 8217 using-declarations. In particular, using-declarations referring to 8218 a dependent type now work as expected ([13]bug c++/14258). 8219 * The ELF symbol visibility of a template instantiation is now 8220 properly constrained by the visibility of its template arguments 8221 ([14]bug c++/35688). 8222 8223 Runtime Library (libstdc++) 8224 8225 * [15]Improved experimental support for the new ISO C++ standard, 8226 C++11, including: 8227 + using noexcept in most of the library; 8228 + implementations of pointer_traits, allocator_traits and 8229 scoped_allocator_adaptor; 8230 + uses-allocator construction for tuple; 8231 + vector meets the allocator-aware container requirements; 8232 + replacing monotonic_clock with steady_clock; 8233 + enabling the thread support library on most POSIX targets; 8234 + many small improvements to conform to the FDIS. 8235 * Added --enable-clocale=newlib configure option. 8236 * Debug Mode iterators for unordered associative containers. 8237 * Avoid polluting the global namespace and do not include <unistd.h>. 8238 8239 Fortran 8240 8241 * The compile flag [16]-fstack-arrays has been added, which causes 8242 all local arrays to be put on stack memory. For some programs this 8243 will improve the performance significantly. If your program uses 8244 very large local arrays, it is possible that you will have to 8245 extend your runtime limits for stack memory. 8246 * The [17]-Ofast flag now also implies [18]-fno-protect-parens and 8247 [19]-fstack-arrays. 8248 * Front-end optimizations can now be selected by the 8249 [20]-ffrontend-optimize option and deselected by the 8250 -fno-frontend-optimize option. 8251 * When front-end optimization removes a function call, 8252 [21]-Wfunction-elimination warns about that. 8253 * When performing front-end-optimization, the 8254 [22]-faggressive-function-elimination option allows the removal of 8255 duplicate function calls even for impure functions. 8256 * The flag [23]-Wreal-q-constant has been added, which warns if 8257 floating-point literals have been specified using q (such as 8258 1.0q0); the q marker is now supported as a vendor extension to 8259 denote quad precision (REAL(16) or, if not available, REAL(10)). 8260 Consider using a kind parameter (such as in 1.0_qp) instead, which 8261 can be obtained via [24]SELECTED_REAL_KIND. 8262 * The GFORTRAN_USE_STDERR environment variable has been removed. GNU 8263 Fortran now always prints error messages to standard error. If you 8264 wish to redirect standard error, please consult the manual for your 8265 OS, shell, batch environment etc. as appropriate. 8266 * The -fdump-core option and GFORTRAN_ERROR_DUMPCORE environment 8267 variable have been removed. When encountering a serious error, 8268 gfortran will now always abort the program. Whether a core dump is 8269 generated depends on the user environment settings; see the ulimit 8270 -c setting for POSIX shells, limit coredumpsize for C shells, and 8271 the [25]WER user-mode dumps settings on Windows. 8272 * The [26]-fbacktrace option is now enabled by default. When 8273 encountering a fatal error, gfortran will attempt to print a 8274 backtrace to standard error before aborting. It can be disabled 8275 with -fno-backtrace. Note: On POSIX targets with the addr2line 8276 utility from GNU binutils, GNU Fortran can print a backtrace with 8277 function name, file name, line number information in addition to 8278 the addresses; otherwise only the addresses are printed. 8279 * [27]Fortran 2003: 8280 + Generic interface names which have the same name as derived 8281 types are now supported, which allows to write constructor 8282 functions. Note that Fortran does not support static 8283 constructor functions; only default initialization or an 8284 explicit structure-constructor initialization are available. 8285 + [28]Polymorphic (class) arrays are now supported. 8286 * [29]Fortran 2008: 8287 + Support for the DO CONCURRENT construct has been added, which 8288 allows the user to specify that individual loop iterations 8289 have no interdependencies. 8290 + [30]Coarrays: Full single-image support except for polymorphic 8291 coarrays. Additionally, preliminary support for multiple 8292 images via an MPI-based [31]coarray communication library has 8293 been added. Note: The library version is not yet usable as 8294 remote coarray access is not yet possible. 8295 * [32]TS 29113: 8296 + New flag [33]-std=f2008ts permits programs that are expected 8297 to conform to the Fortran 2008 standard and the draft 8298 Technical Specification (TS) 29113 on Further Interoperability 8299 of Fortran with C. 8300 + The OPTIONAL attribute is now allowed for dummy arguments of 8301 BIND(C) procedures. 8302 + The RANK intrinsic has been added. 8303 + The implementation of the ASYNCHRONOUS attribute in GCC is 8304 compatible with the candidate draft of TS 29113 (since GCC 8305 4.6). 8306 8307 Go 8308 8309 * GCC 4.7 implements the [34]Go 1 language standard. The library 8310 support in 4.7.0 is not quite complete, due to release timing. 8311 Release 4.7.1 includes complete support for Go 1. The Go library is 8312 from the Go 1.0.1 release. 8313 * Go has been tested on GNU/Linux and Solaris platforms. It may work 8314 on other platforms as well. 8315 8316 New Targets and Target Specific Improvements 8317 8318 ARM 8319 8320 * GCC now supports the Cortex-A7 processor implementing the v7-a 8321 version of the architecture using the option -mcpu=cortex-a7. 8322 * The default vector size in auto-vectorization for NEON is now 128 8323 bits. If vectorization fails thusly, the vectorizer tries again 8324 with 64-bit vectors. 8325 * A new option -mvectorize-with-neon-double was added to allow users 8326 to change the vector size to 64 bits. 8327 8328 AVR 8329 8330 * GCC now supports the XMEGA architecture. This requires GNU binutils 8331 2.22 or later. 8332 * Support for the [35]named address spaces __flash, __flash1, ..., 8333 __flash5 and __memx has been added. These address spaces locate 8334 read-only data in flash memory and allow reading from flash memory 8335 by means of ordinary C code, i.e. without the need of (inline) 8336 assembler code: 8337 8338 const __flash int values[] = { 42, 31 }; 8339 8340 int add_values (const __flash int *p, int i) 8341 { 8342 return values[i] + *p; 8343 } 8344 8345 * Support has been added for the AVR-specific configure option 8346 --with-avrlibc=yes in order to arrange for better integration of 8347 [36]AVR-Libc. This configure option is supported in avr-gcc 4.7.2 8348 and newer and will only take effect in non-RTEMS configurations. If 8349 avr-gcc is configured for RTEMS, the option will be ignored which 8350 is the same as specifying --with-avrlibc=no. See [37]PR54461 for 8351 more technical details. 8352 * Support for AVR-specific [38]built-in functions has been added. 8353 * Support has been added for the signed and unsigned 24-bit scalar 8354 integer types __int24 and __uint24. 8355 * New command-line options -maccumulate-args, -mbranch-cost=cost and 8356 -mstrict-X were added to allow better fine-tuning of code 8357 optimization. 8358 * The command-line option -fdata-sections now also takes affect on 8359 the section names of variables with the progmem attribute. 8360 * A new inline assembler print modifier %i to print a RAM address as 8361 I/O address has been added: 8362 8363 #include <avr/io.h> /* Port Definitions from AVR-LibC */ 8364 8365 void set_portb (uint8_t value) 8366 { 8367 asm volatile ("out %i0, %1" :: "n" (&PORTB), "r" (value) : "memory"); 8368 } 8369 8370 The offset between an I/O address and the RAM address for that I/O 8371 location is device-specific. This offset is taken into account when 8372 printing a RAM address with the %i modifier so that the address is 8373 suitable to be used as operand in an I/O command. The address must 8374 be a constant integer known at compile time. 8375 * The inline assembler constraint "R" to represent integers in the 8376 range -6 ... 5 has been removed without replacement. 8377 * Many optimizations to: 8378 + 64-bit integer arithmetic 8379 + Widening multiplication 8380 + Integer division by a constant 8381 + Avoid constant reloading in multi-byte instructions. 8382 + Micro-optimizations for special instruction sequences. 8383 + Generic built-in functions like __builtin_ffs*, 8384 __builtin_clz*, etc. 8385 + If-else decision trees generated by switch instructions 8386 + Merging of data located in flash memory 8387 + New libgcc variants for devices with 8-bit wide stack pointer 8388 + ... 8389 * Better documentation: 8390 + Handling of EIND and indirect jumps on devices with more than 8391 128 KiB of program memory. 8392 + Handling of the RAMPD, RAMPX, RAMPY and RAMPZ special function 8393 registers. 8394 + Function attributes OS_main and OS_task. 8395 + AVR-specific built-in macros. 8396 8397 C6X 8398 8399 * Support has been added for the Texas Instruments C6X family of 8400 processors. 8401 8402 CR16 8403 8404 * Support has been added for National Semiconductor's CR16 8405 architecture. 8406 8407 Epiphany 8408 8409 * Support has been added for Adapteva's Epiphany architecture. 8410 8411 IA-32/x86-64 8412 8413 * Support for Intel AVX2 intrinsics, built-in functions and code 8414 generation is available via -mavx2. 8415 * Support for Intel BMI2 intrinsics, built-in functions and code 8416 generation is available via -mbmi2. 8417 * Implementation and automatic generation of __builtin_clz* using the 8418 lzcnt instruction is available via -mlzcnt. 8419 * Support for Intel FMA3 intrinsics and code generation is available 8420 via -mfma. 8421 * A new -mfsgsbase command-line option is available that makes GCC 8422 generate new segment register read/write instructions through 8423 dedicated built-ins. 8424 * Support for the new Intel rdrnd instruction is available via 8425 -mrdrnd. 8426 * Two additional AVX vector conversion instructions are available via 8427 -mf16c. 8428 * Support for new Intel processor codename IvyBridge with RDRND, 8429 FSGSBASE and F16C is available through -march=core-avx-i. 8430 * Support for the new Intel processor codename Haswell with AVX2, 8431 FMA, BMI, BMI2, LZCNT is available through -march=core-avx2. 8432 * Support for new AMD family 15h processors (Piledriver core) is now 8433 available through -march=bdver2 and -mtune=bdver2 options. 8434 * Support for [39]the x32 psABI is now available through the -mx32 8435 option. 8436 * Windows mingw targets are using the -mms-bitfields option by 8437 default. 8438 * Windows x86 targets are using the __thiscall calling convention for 8439 C++ class-member functions. 8440 * Support for the configure option --with-threads=posix for Windows 8441 mingw targets. 8442 8443 MIPS 8444 8445 * GCC now supports thread-local storage (TLS) for MIPS16. This 8446 requires GNU binutils 2.22 or later. 8447 * GCC can now generate code specifically for the Cavium Octeon+ and 8448 Octeon2 processors. The associated command-line options are 8449 -march=octeon+ and -march=octeon2 respectively. Both options 8450 require GNU binutils 2.22 or later. 8451 * GCC can now work around certain 24k errata, under the control of 8452 the command-line option -mfix-24k. These workarounds require GNU 8453 binutils 2.20 or later. 8454 * 32-bit MIPS GNU/Linux targets such as mips-linux-gnu can now build 8455 n32 and n64 multilibs. The result is effectively a 64-bit GNU/Linux 8456 toolchain that generates 32-bit code by default. Use the 8457 configure-time option --enable-targets=all to select these extra 8458 multilibs. 8459 * Passing -fno-delayed-branch now also stops the assembler from 8460 automatically filling delay slots. 8461 8462 PowerPC/PowerPC64 8463 8464 * Vectors of type vector long long or vector long are passed and 8465 returned using the same method as other vectors with the VSX 8466 instruction set. Previously GCC did not adhere to the ABI for 8467 128-bit vectors with 64-bit integer base types (PR 48857). This 8468 will also be fixed in the GCC 4.6.1 and 4.5.4 releases. 8469 * A new option -mno-pointers-to-nested-functions was added to allow 8470 AIX 32-bit/64-bit and GNU/Linux 64-bit PowerPC users to specify 8471 that the compiler should not load up the chain register (r11) 8472 before calling a function through a pointer. If you use this 8473 option, you cannot call nested functions through a pointer, or call 8474 other languages that might use the static chain. 8475 * A new option msave-toc-indirect was added to allow AIX 8476 32-bit/64-bit and GNU/Linux 64-bit PowerPC users control whether we 8477 save the TOC in the prologue for indirect calls or generate the 8478 save inline. This can speed up some programs that call through a 8479 function pointer a lot, but it can slow down other functions that 8480 only call through a function pointer in exceptional cases. 8481 * The PowerPC port will now enable machine-specific built-in 8482 functions when the user switches the target machine using the 8483 #pragma GCC target or __attribute__ ((__target__ ("target"))) code 8484 sequences. In addition, the target macros are updated. However, due 8485 to the way the -save-temps switch is implemented, you won't see the 8486 effect of these additional macros being defined in preprocessor 8487 output. 8488 8489 SH 8490 8491 * A new option -msoft-atomic has been added. When it is specified, 8492 GCC will generate GNU/Linux-compatible gUSA atomic sequences for 8493 the new __atomic routines. 8494 * Since it is neither supported by GAS nor officially documented, 8495 code generation for little endian SH2A has been disabled. 8496 Specifying -ml with -m2a* will now result in a compiler error. 8497 * The defunct -mbranch-cost option has been fixed. 8498 * Some improvements to the generated code of: 8499 + Utilization of the tst #imm,R0 instruction. 8500 + Dynamic shift instructions on SH2A. 8501 + Integer absolute value calculations. 8502 * The -mdiv= option for targets other than SHmedia has been fixed and 8503 documented. 8504 8505 SPARC 8506 8507 * The option -mflat has been reinstated. When it is specified, the 8508 compiler will generate code for a single register window model. 8509 This is essentially a new implementation and the corresponding 8510 debugger support has been added to GDB 7.4. 8511 * Support for the options -mtune=native and -mcpu=native has been 8512 added on selected native platforms (GNU/Linux and Solaris). 8513 * Support for the SPARC T3 (Niagara 3) processor has been added. 8514 * VIS: 8515 + An intrinsics header visintrin.h has been added. 8516 + Builtin intrinsics for the VIS 1.0 edge handling and pixel 8517 compare instructions have been added. 8518 + The little-endian version of alignaddr is now supported. 8519 + When possible, VIS builtins are marked const, which should 8520 increase the compiler's ability to optimize VIS operations. 8521 + The compiler now properly tracks the %gsr register and how it 8522 behaves as an input for various VIS instructions. 8523 + Akin to fzero, the compiler can now generate fone instructions 8524 in order to set all of the bits of a floating-point register 8525 to 1. 8526 + The documentation for the VIS intrinsics in the GCC manual has 8527 been brought up to date and many inaccuracies were fixed. 8528 + Intrinsics for the VIS 2.0 bmask, bshuffle, and 8529 non-condition-code setting edge instructions have been added. 8530 Their availability is controlled by the new -mvis2 and 8531 -mno-vis2 options. They are enabled by default on 8532 UltraSPARC-III and later CPUs. 8533 * Support for UltraSPARC Fused Multiply-Add floating-point extensions 8534 has been added. These instructions are enabled by default on SPARC 8535 T3 (Niagara 3) and later CPUs. 8536 8537 TILE-Gx/TILEPro 8538 8539 * Support has been added for the Tilera TILE-Gx and TILEPro families 8540 of processors. 8541 8542 Other significant improvements 8543 8544 * A new option (-grecord-gcc-switches) was added that appends 8545 compiler command-line options that might affect code generation to 8546 the DW_AT_producer attribute string in the DWARF debugging 8547 information. 8548 * GCC now supports various new GNU extensions to the DWARF debugging 8549 information format, like [40]entry value and [41]call site 8550 information, [42]typed DWARF stack or [43]a more compact macro 8551 representation. Support for these extensions has been added to GDB 8552 7.4. They can be disabled through the -gstrict-dwarf command-line 8553 option. 8554 8555 GCC 4.7.1 8556 8557 This is the [44]list of problem reports (PRs) from GCC's bug tracking 8558 system that are known to be fixed in the 4.7.1 release. This list might 8559 not be complete (that is, it is possible that some PRs that have been 8560 fixed are not listed here). 8561 8562 The Go front end in the 4.7.1 release fully supports the [45]Go 1 8563 language standard. 8564 8565 GCC 4.7.2 8566 8567 This is the [46]list of problem reports (PRs) from GCC's bug tracking 8568 system that are known to be fixed in the 4.7.2 release. This list might 8569 not be complete (that is, it is possible that some PRs that have been 8570 fixed are not listed here). 8571 8572 GCC 4.7.3 8573 8574 This is the [47]list of problem reports (PRs) from GCC's bug tracking 8575 system that are known to be fixed in the 4.7.3 release. This list might 8576 not be complete (that is, it is possible that some PRs that have been 8577 fixed are not listed here). 8578 8579 GCC 4.7.4 8580 8581 This is the [48]list of problem reports (PRs) from GCC's bug tracking 8582 system that are known to be fixed in the 4.7.4 release. This list might 8583 not be complete (that is, it is possible that some PRs that have been 8584 fixed are not listed here). 8585 8586 8587 For questions related to the use of GCC, please consult these web 8588 pages and the [49]GCC manuals. If that fails, the 8589 [50]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8590 web pages and the development of GCC are welcome on our developer 8591 list at [51]gcc (a] gcc.gnu.org. All of [52]our lists have public 8592 archives. 8593 8594 Copyright (C) [53]Free Software Foundation, Inc. Verbatim copying and 8595 distribution of this entire article is permitted in any medium, 8596 provided this notice is preserved. 8597 8598 These pages are [54]maintained by the GCC team. Last modified 8599 2019-11-28[55]. 8600 8601 References 8602 8603 1. https://gcc.gnu.org/ml/gcc-patches/2011-03/msg01263.html 8604 2. http://savannah.nongnu.org/bugs/?35407 8605 3. https://gcc.gnu.org/PR18145 8606 4. https://gcc.gnu.org/gcc-4.7/porting_to.html 8607 5. https://gcc.gnu.org/wiki/TransactionalMemory 8608 6. https://gcc.gnu.org/wiki/Atomic/GCCMM 8609 7. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8610 8. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8611 9. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8612 10. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8613 11. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8614 12. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html 8615 13. https://gcc.gnu.org/PR14258 8616 14. https://gcc.gnu.org/PR35688 8617 15. https://gcc.gnu.org/onlinedocs/gcc-4.7.4/libstdc++/manual/manual/status.html#status.iso.2011 8618 16. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 8619 17. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Optimize-Options.html#index-Ofast-689 8620 18. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfno-protect-parens_007d-270 8621 19. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254 8622 20. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfrontend-optimize_007d-275 8623 21. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWfunction-elimination_007d-170 8624 22. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfaggressive-function-elimination_007d-270 8625 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 8626 24. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/SELECTED_005fREAL_005fKIND.html 8627 25. https://docs.microsoft.com/en-us/windows/win32/wer/collecting-user-mode-dumps 8628 26. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Debugging-Options.html#index-g_t_0040code_007bfno-backtrace_007d-183 8629 27. https://gcc.gnu.org/wiki/Fortran2003Status 8630 28. https://gcc.gnu.org/wiki/OOP 8631 29. https://gcc.gnu.org/wiki/Fortran2008Status 8632 30. https://gcc.gnu.org/wiki/Coarray 8633 31. https://gcc.gnu.org/wiki/CoarrayLib 8634 32. https://gcc.gnu.org/wiki/TS29113Status 8635 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 8636 34. https://golang.org/doc/go1 8637 35. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Named-Address-Spaces.html 8638 36. http://nongnu.org/avr-libc/ 8639 37. https://gcc.gnu.org/PR54461 8640 38. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/AVR-Built%5f002din-Functions.html 8641 39. https://sites.google.com/site/x32abi/ 8642 40. http://www.dwarfstd.org/ShowIssue.php?issue=100909.1 8643 41. http://www.dwarfstd.org/ShowIssue.php?issue=100909.2 8644 42. http://www.dwarfstd.org/ShowIssue.php?issue=140425.1 8645 43. http://www.dwarfstd.org/ShowIssue.php?issue=110722.1 8646 44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.1 8647 45. https://golang.org/doc/go1 8648 46. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.2 8649 47. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.3 8650 48. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.4 8651 49. https://gcc.gnu.org/onlinedocs/ 8652 50. mailto:gcc-help (a] gcc.gnu.org 8653 51. mailto:gcc (a] gcc.gnu.org 8654 52. https://gcc.gnu.org/lists.html 8655 53. https://www.fsf.org/ 8656 54. https://gcc.gnu.org/about.html 8657 55. http://validator.w3.org/check/referer 8658 ====================================================================== 8659 http://gcc.gnu.org/gcc-4.6/index.html 8660 8661 GCC 4.6 Release Series 8662 8663 (This release series is no longer supported.) 8664 8665 April 12, 2013 8666 8667 The [1]GNU project and the GCC developers are pleased to announce the 8668 release of GCC 4.6.4. 8669 8670 This release is a bug-fix release, containing fixes for regressions in 8671 GCC 4.6.3 relative to previous releases of GCC. 8672 8673 Release History 8674 8675 GCC 4.6.4 8676 April 12, 2013 ([2]changes, [3]documentation) 8677 8678 GCC 4.6.3 8679 March 1, 2012 ([4]changes, [5]documentation) 8680 8681 GCC 4.6.2 8682 October 26, 2011 ([6]changes, [7]documentation) 8683 8684 GCC 4.6.1 8685 June 27, 2011 ([8]changes, [9]documentation) 8686 8687 GCC 4.6.0 8688 March 25, 2011 ([10]changes, [11]documentation) 8689 8690 References and Acknowledgements 8691 8692 GCC used to stand for the GNU C Compiler, but since the compiler 8693 supports several other languages aside from C, it now stands for the 8694 GNU Compiler Collection. 8695 8696 A list of [12]successful builds is updated as new information becomes 8697 available. 8698 8699 The GCC developers would like to thank the numerous people that have 8700 contributed new features, improvements, bug fixes, and other changes as 8701 well as test results to GCC. This [13]amazing group of volunteers is 8702 what makes GCC successful. 8703 8704 For additional information about GCC please refer to the [14]GCC 8705 project web site or contact the [15]GCC development mailing list. 8706 8707 To obtain GCC please use [16]our mirror sites or [17]our version 8708 control system. 8709 8710 8711 For questions related to the use of GCC, please consult these web 8712 pages and the [18]GCC manuals. If that fails, the 8713 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 8714 web pages and the development of GCC are welcome on our developer 8715 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 8716 archives. 8717 8718 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 8719 distribution of this entire article is permitted in any medium, 8720 provided this notice is preserved. 8721 8722 These pages are [23]maintained by the GCC team. Last modified 8723 2020-01-14[24]. 8724 8725 References 8726 8727 1. http://www.gnu.org/ 8728 2. http://gcc.gnu.org/gcc-4.6/changes.html 8729 3. https://gcc.gnu.org/onlinedocs/4.6.4/ 8730 4. http://gcc.gnu.org/gcc-4.6/changes.html 8731 5. https://gcc.gnu.org/onlinedocs/4.6.3/ 8732 6. http://gcc.gnu.org/gcc-4.6/changes.html 8733 7. https://gcc.gnu.org/onlinedocs/4.6.2/ 8734 8. http://gcc.gnu.org/gcc-4.6/changes.html 8735 9. https://gcc.gnu.org/onlinedocs/4.6.1/ 8736 10. http://gcc.gnu.org/gcc-4.6/changes.html 8737 11. https://gcc.gnu.org/onlinedocs/4.6.0/ 8738 12. http://gcc.gnu.org/gcc-4.6/buildstat.html 8739 13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 8740 14. http://gcc.gnu.org/index.html 8741 15. mailto:gcc (a] gcc.gnu.org 8742 16. http://gcc.gnu.org/mirrors.html 8743 17. http://gcc.gnu.org/git.html 8744 18. https://gcc.gnu.org/onlinedocs/ 8745 19. mailto:gcc-help (a] gcc.gnu.org 8746 20. mailto:gcc (a] gcc.gnu.org 8747 21. https://gcc.gnu.org/lists.html 8748 22. https://www.fsf.org/ 8749 23. https://gcc.gnu.org/about.html 8750 24. http://validator.w3.org/check/referer 8751 ====================================================================== 8752 http://gcc.gnu.org/gcc-4.6/changes.html 8753 8754 GCC 4.6 Release Series 8755 Changes, New Features, and Fixes 8756 8757 Caveats 8758 8759 * The options -b <machine> and -V <version> have been removed because 8760 they were unreliable. Instead, users should directly run 8761 <machine>-gcc when cross-compiling, or <machine>-gcc-<version> to 8762 run a different version of gcc. 8763 * GCC now has stricter checks for invalid command-line options. In 8764 particular, when gcc was called to link object files rather than 8765 compile source code, it would previously accept and ignore all 8766 options starting with --, including linker options such as 8767 --as-needed and --export-dynamic, although such options would 8768 result in errors if any source code was compiled. Such options, if 8769 unknown to the compiler, are now rejected in all cases; if the 8770 intent was to pass them to the linker, options such as 8771 -Wl,--as-needed should be used. 8772 * Versions of the GNU C library up to and including 2.11.1 included 8773 an [1]incorrect implementation of the cproj function. GCC optimizes 8774 its builtin cproj according to the behavior specified and allowed 8775 by the ISO C99 standard. If you want to avoid discrepancies between 8776 the C library and GCC's builtin transformations when using cproj in 8777 your code, use GLIBC 2.12 or later. If you are using an older GLIBC 8778 and actually rely on the incorrect behavior of cproj, then you can 8779 disable GCC's transformations using -fno-builtin-cproj. 8780 * The C-only intermodule optimization framework (IMA, enabled by 8781 -combine) has been removed in favor of the new generic link-time 8782 optimization framework (LTO) introduced in [2]GCC 4.5.0. 8783 * GCC now ships with the LGPL-licensed libquadmath library, which 8784 provides quad-precision mathematical functions for targets with a 8785 __float128 datatype. __float128 is available for targets on 32-bit 8786 x86, x86-64 and Itanium architectures. The libquadmath library is 8787 automatically built on such targets when building the Fortran 8788 compiler. 8789 * New -Wunused-but-set-variable and -Wunused-but-set-parameter 8790 warnings were added for C, C++, Objective-C and Objective-C++. 8791 These warnings diagnose variables respective parameters which are 8792 only set in the code and never otherwise used. Usually such 8793 variables are useless and often even the value assigned to them is 8794 computed needlessly, sometimes expensively. The 8795 -Wunused-but-set-variable warning is enabled by default by -Wall 8796 flag and -Wunused-but-set-parameter by -Wall -Wextra flags. 8797 * On ARM, a bug has been fixed in GCC's implementation of the AAPCS 8798 rules for the layout of vectors that could lead to wrong code being 8799 generated. Vectors larger than 8 bytes in size are now by default 8800 aligned to an 8-byte boundary. This is an ABI change: code that 8801 makes explicit use of vector types may be incompatible with binary 8802 objects built with older versions of GCC. Auto-vectorized code is 8803 not affected by this change. (This change affects GCC versions 8804 4.6.4 and later, with the exception of versions 4.7.0 and 4.7.1.) 8805 * On AVR, variables with the progmem attribute to locate data in 8806 flash memory must be qualified as const. 8807 * Support for a number of older systems and recently unmaintained or 8808 untested target ports of GCC has been declared obsolete in GCC 4.6. 8809 Unless there is activity to revive them, the next release of GCC 8810 will have their sources permanently removed. 8811 All GCC ports for the following processor architectures have been 8812 declared obsolete: 8813 + Argonaut ARC (arc-*) 8814 + National Semiconductor CRX (crx-*) 8815 + Motorola 68HC11 and 68HC12 (m68hc11-*-*, m6811-*-*, 8816 m68hc12-*-*, m6812-*-*) 8817 + Sunplus S+core (score-*) 8818 The following ports for individual systems on particular 8819 architectures have been obsoleted: 8820 + Interix (i[34567]86-*-interix3*) 8821 + NetWare x86 (i[3456x]86-*-netware*) 8822 + Generic ARM PE (arm-*-pe* other than arm*-wince-pe*) 8823 + MCore PE (mcore-*-pe*) 8824 + SH SymbianOS (sh*-*-symbianelf*) 8825 + GNU Hurd on Alpha and PowerPC (alpha*-*-gnu*, powerpc*-*-gnu*) 8826 + M68K uClinux old ABI (m68k-*-uclinuxoldabi*) 8827 + a.out NetBSD (arm*-*-netbsd*, i[34567]86-*-netbsd*, 8828 vax-*-netbsd*, but not *-*-netbsdelf*) 8829 The i[34567]86-*-pe alias for Cygwin targets has also been 8830 obsoleted; users should configure for i[34567]86-*-cygwin* instead. 8831 Certain configure options to control the set of libraries built 8832 with GCC on some targets have been obsoleted. On ARM targets, the 8833 options --disable-fpu, --disable-26bit, --disable-underscore, 8834 --disable-interwork, --disable-biendian and --disable-nofmult have 8835 been obsoleted. On MIPS targets, the options 8836 --disable-single-float, --disable-biendian and --disable-softfloat 8837 have been obsoleted. 8838 * Support has been removed for all the [3]configurations obsoleted in 8839 GCC 4.5. 8840 * More information on porting to GCC 4.6 from previous versions of 8841 GCC can be found in the [4]porting guide for this release. 8842 8843 General Optimizer Improvements 8844 8845 * A new general optimization level, -Ofast, has been introduced. It 8846 combines the existing optimization level -O3 with options that can 8847 affect standards compliance but result in better optimized code. 8848 For example, -Ofast enables -ffast-math. 8849 * Link-time optimization improvements: 8850 + The [5]Scalable Whole Program Optimizer (WHOPR) project has 8851 stabilized to the point of being usable. It has become the 8852 default mode when using the LTO optimization model. Link time 8853 optimization can now split itself into multiple parallel 8854 compilations. Parallelism is controlled with -flto=n (where n 8855 specifies the number of compilations to execute in parallel). 8856 GCC can also cooperate with a GNU make job server by 8857 specifying the -flto=jobserver option and adding + to the 8858 beginning of the Makefile rule executing the linker. 8859 Classical LTO mode can be enforced by -flto-partition=none. 8860 This may result in small code quality improvements. 8861 + A large number of bugs were fixed. GCC itself, Mozilla Firefox 8862 and other large applications can be built with LTO enabled. 8863 + The linker plugin support improvements 8864 o Linker plugin is now enabled by default when the linker 8865 is detected to have plugin support. This is the case for 8866 GNU ld 2.21.51 or newer (on ELF and Cygwin targets) and 8867 the Gold linker on ELF targets. Plugin support of the 8868 Apple linker on Darwin is not compatible with GCC. The 8869 linker plugin can also be controlled by the 8870 -fuse-linker-plugin command-line option. 8871 o Resolution information from the linker plugin is used to 8872 drive whole program assumptions. Use of the linker plugin 8873 results in more aggressive optimization on binaries and 8874 on shared libraries that use the hidden visibility 8875 attribute. Consequently the use of -fwhole-program is not 8876 necessary in addition to LTO. 8877 + Hidden symbols used from non-LTO objects now have to be 8878 explicitly annotated with externally_visible when the linker 8879 plugin is not used. 8880 + C++ inline functions and virtual tables are now privatized 8881 more aggressively, leading to better inter-procedural 8882 optimization and faster dynamic linking. 8883 + Memory usage and intermediate language streaming performance 8884 have been improved. 8885 + Static constructors and destructors from individual units are 8886 inlined into a single function. This can significantly improve 8887 startup times of large C++ applications where static 8888 constructors are very common. For example, static constructors 8889 are used when including the iostream header. 8890 + Support for the Ada language has been added. 8891 * Interprocedural optimization improvements 8892 + The interprocedural framework was re-tuned for link time 8893 optimization. Several scalability issues were resolved. 8894 + Improved auto-detection of const and pure functions. Newly, 8895 noreturn functions are auto-detected. 8896 The [6]-Wsuggest-attribute=[const|pure|noreturn] flag is 8897 available that informs users when adding attributes to headers 8898 might improve code generation. 8899 + A number of inlining heuristic improvements. In particular: 8900 o Partial inlining is now supported and enabled by default 8901 at -O2 and greater. The feature can be controlled via 8902 -fpartial-inlining. 8903 Partial inlining splits functions with short hot path to 8904 return. This allows more aggressive inlining of the hot 8905 path leading to better performance and often to code size 8906 reductions (because cold parts of functions are not 8907 duplicated). 8908 o Scalability for large compilation units was improved 8909 significantly. 8910 o Inlining of callbacks is now more aggressive. 8911 o Virtual methods are considered for inlining when the 8912 caller is inlined and devirtualization is then possible. 8913 o Inlining when optimizing for size (either in cold regions 8914 of a program or when compiling with -Os) was improved to 8915 better handle C++ programs with larger abstraction 8916 penalty, leading to smaller and faster code. 8917 + The IPA reference optimization pass detecting global variables 8918 used or modified by functions was strengthened and sped up. 8919 + Functions whose address was taken are now optimized out when 8920 all references to them are dead. 8921 + A new inter-procedural static profile estimation pass detects 8922 functions that are executed once or unlikely to be executed. 8923 Unlikely executed functions are optimized for size. Functions 8924 executed once are optimized for size except for the inner 8925 loops. 8926 + On most targets with named section support, functions used 8927 only at startup (static constructors and main), functions used 8928 only at exit and functions detected to be cold are placed into 8929 separate text segment subsections. This extends the 8930 -freorder-functions feature and is controlled by the same 8931 switch. The goal is to improve the startup time of large C++ 8932 programs. 8933 Proper function placement requires linker support. GNU ld 8934 2.21.51 on ELF targets was updated to place those functions 8935 together within the text section leading to better code 8936 locality and faster startup times of large C++ programs. The 8937 feature is also supported in the Apple linker. Support in the 8938 gold linker is planned. 8939 * A new switch -fstack-usage has been added. It makes the compiler 8940 output stack usage information for the program, on a per-function 8941 basis, in an auxiliary file. 8942 * A new switch -fcombine-stack-adjustments has been added. It can be 8943 used to enable or disable the compiler's stack-slot combining pass 8944 which before was enabled automatically at -O1 and above, but could 8945 not be controlled on its own. 8946 * A new switch -fstrict-volatile-bitfields has been added. Using it 8947 indicates that accesses to volatile bitfields should use a single 8948 access of the width of the field's type. This option can be useful 8949 for precisely defining and accessing memory-mapped peripheral 8950 registers from C or C++. 8951 8952 Compile time and memory usage improvements 8953 8954 * Datastructures used by the dataflow framework in GCC were 8955 reorganized for better memory usage and more cache locality. 8956 Compile time is improved especially on units with large functions 8957 (possibly resulting from a lot of inlining) not fitting into the 8958 processor cache. The compile time of the GCC C compiler binary with 8959 link-time optimization went down by over 10% (benchmarked on x86-64 8960 target). 8961 8962 New Languages and Language specific improvements 8963 8964 Ada 8965 8966 * Stack checking has been improved on selected architectures (Alpha, 8967 IA-32/x86-64, RS/6000 and SPARC): it now will detect stack 8968 overflows in all cases on these architectures. 8969 * Initial support for Ada 2012 has been added. 8970 8971 C family 8972 8973 * A new warning, enabled by -Wdouble-promotion, has been added that 8974 warns about cases where a value of type float is implicitly 8975 promoted to double. This is especially helpful for CPUs that handle 8976 the former in hardware, but emulate the latter in software. 8977 * A new function attribute leaf was introduced. This attribute allows 8978 better inter-procedural optimization across calls to functions that 8979 return to the current unit only via returning or exception 8980 handling. This is the case for most library functions that have no 8981 callbacks. 8982 * Support for a new data type __int128 for targets having wide enough 8983 machine-mode support. 8984 * The new function attribute callee_pop_aggregate allows to specify 8985 if the caller or callee is responsible for popping the aggregate 8986 return pointer value from the stack. 8987 * Support for selectively enabling and disabling warnings via #pragma 8988 GCC diagnostic has been added. For instance: 8989 #pragma GCC diagnostic error "-Wuninitialized" 8990 foo(a); /* error is given for this one */ 8991 #pragma GCC diagnostic push 8992 #pragma GCC diagnostic ignored "-Wuninitialized" 8993 foo(b); /* no diagnostic for this one */ 8994 #pragma GCC diagnostic pop 8995 foo(c); /* error is given for this one */ 8996 #pragma GCC diagnostic pop 8997 foo(d); /* depends on command-line options */ 8998 8999 * The -fmax-errors=N option is now supported. Using this option 9000 causes the compiler to exit after N errors have been issued. 9001 9002 C 9003 9004 * There is now experimental support for some features from the 9005 upcoming C1X revision of the ISO C standard. This support may be 9006 selected with -std=c1x, or -std=gnu1x for C1X with GNU extensions. 9007 Note that this support is experimental and may change incompatibly 9008 in future releases for consistency with changes to the C1X standard 9009 draft. The following features are newly supported as described in 9010 the N1539 draft of C1X (with changes agreed at the March 2011 WG14 9011 meeting); some other features were already supported with no 9012 compiler changes being needed, or have some support but not in full 9013 accord with N1539 (as amended). 9014 + Static assertions (_Static_assert keyword) 9015 + Typedef redefinition 9016 + New macros in <float.h> 9017 + Anonymous structures and unions 9018 * The new -fplan9-extensions option directs the compiler to support 9019 some extensions for anonymous struct fields which are implemented 9020 by the Plan 9 compiler. A pointer to a struct may be automatically 9021 converted to a pointer to an anonymous field when calling a 9022 function, in order to make the types match. An anonymous struct 9023 field whose type is a typedef name may be referred to using the 9024 typedef name. 9025 9026 C++ 9027 9028 * Improved [7]experimental support for the upcoming C++0x ISO C++ 9029 standard, including support for constexpr (thanks to Gabriel Dos 9030 Reis and Jason Merrill), nullptr (thanks to Magnus Fromreide), 9031 noexcept, unrestricted unions, range-based for loops (thanks to 9032 Rodrigo Rivas Costa), opaque enum declarations (thanks also to 9033 Rodrigo), implicitly deleted functions and implicit move 9034 constructors. 9035 * When an extern declaration within a function does not match a 9036 declaration in the enclosing context, G++ now properly declares the 9037 name within the namespace of the function rather than the namespace 9038 which was open just before the function definition ([8]c++/43145). 9039 * GCC now warns by default when casting integers to larger pointer 9040 types. These warnings can be disabled with the option 9041 -Wno-int-to-pointer-cast, which is now also available in C++. 9042 * G++ no longer optimizes using the assumption that a value of 9043 enumeration type will fall within the range specified by the 9044 standard, since that assumption is easily violated with a 9045 conversion from integer type ([9]c++/43680). The old behavior can 9046 be restored with -fstrict-enums. 9047 * The new -fnothrow-opt flag changes the semantics of a throw() 9048 exception specification to match the proposed semantics of the 9049 noexcept specification: just call terminate if an exception tries 9050 to propagate out of a function with such an exception 9051 specification. This dramatically reduces or eliminates the code 9052 size overhead from adding the exception specification. 9053 * The new -Wnoexcept flag will suggest adding a noexcept qualifier to 9054 a function that the compiler can tell doesn't throw if it would 9055 change the value of a noexcept expression. 9056 * The -Wshadow option now warns if a local variable or type 9057 declaration shadows another type in C++. Note that the compiler 9058 will not warn if a local variable shadows a struct/class/enum, but 9059 will warn if it shadows an explicit typedef. 9060 * When an identifier is not found in the current scope, G++ now 9061 offers suggestions about which identifier might have been intended. 9062 * G++ now issues clearer diagnostics for missing semicolons after 9063 class, struct, and union definitions. 9064 * G++ now issues clearer diagnostics for missing semicolons after 9065 class member declarations. 9066 * G++ now issues clearer diagnostics when a colon is used in a place 9067 where a double-colon was intended. 9068 * G++ no longer accepts mutable on reference members ([10]c++/33558). 9069 Use -fpermissive to allow the old, non-conforming behaviour. 9070 * A few mangling fixes have been made, to attribute const/volatile on 9071 function pointer types, decltype of a plain decl, and use of a 9072 function parameter in the declaration of another parameter. By 9073 default the compiler still uses the old mangling, but emits aliases 9074 with the new mangling on targets that support strong aliases. Users 9075 can switch over entirely to the new mangling with -fabi-version=5 9076 or -fabi-version=0. -Wabi will now warn about code that uses the 9077 old mangling. 9078 * In 4.6.0 and 4.6.1 G++ no longer allows objects of const-qualified 9079 type to be default initialized unless the type has a user-declared 9080 default constructor. In 4.6.2 G++ implements the proposed 9081 resolution of [11]DR 253, so default initialization is allowed if 9082 it initializes all subobjects. Code that fails to compile can be 9083 fixed by providing an initializer e.g. 9084 struct A { A(); }; 9085 struct B : A { int i; }; 9086 const B b = B(); 9087 Use -fpermissive to allow the old, non-conforming behaviour. 9088 9089 Runtime Library (libstdc++) 9090 9091 * [12]Improved experimental support for the upcoming ISO C++ 9092 standard, C++0x, including using constexpr and nullptr. 9093 * Performance improvements to the [13]Debug Mode, thanks to Franois 9094 Dumont. 9095 * Atomic operations used for reference-counting are annotated so that 9096 they can be understood by race detectors such as Helgrind, see 9097 [14]Data Race Hunting. 9098 * Most libstdc++ standard headers have been changed to no longer 9099 include the cstddef header as an implementation detail. Code that 9100 relied on that header being included as side-effect of including 9101 other standard headers will need to include cstddef explicitly. 9102 9103 Fortran 9104 9105 * On systems supporting the libquadmath library, GNU Fortran now also 9106 supports a quad-precision, kind=16 floating-point data type 9107 (REAL(16), COMPLEX(16)). As the data type is not fully supported in 9108 hardware, calculations might be one to two orders of magnitude 9109 slower than with the 4, 8 or 10 bytes floating-point data types. 9110 This change does not affect systems which support REAL(16) in 9111 hardware nor those which do not support libquadmath. 9112 * Much improved compile time for large array constructors. 9113 * In order to reduce execution time and memory consumption, use of 9114 temporary arrays in assignment expressions is avoided for many 9115 cases. The compiler now reverses loops in order to avoid generating 9116 a temporary array where possible. 9117 * Improved diagnostics, especially with -fwhole-file. 9118 * The -fwhole-file flag is now enabled by default. This improves code 9119 generation and diagnostics. It can be disabled using the deprecated 9120 -fno-whole-file flag. 9121 * Support the generation of Makefile dependencies via the [15]-M... 9122 flags of GCC; you may need to specify the -cpp option in addition. 9123 The dependencies take modules, Fortran's include, and CPP's 9124 #include into account. Note: Using -M for the module path is no 9125 longer supported, use -J instead. 9126 * The flag -Wconversion has been modified to only issue warnings 9127 where a conversion leads to information loss. This drastically 9128 reduces the number of warnings; -Wconversion is thus now enabled 9129 with -Wall. The flag -Wconversion-extra has been added and also 9130 warns about other conversions; -Wconversion-extra typically issues 9131 a huge number of warnings, most of which can be ignored. 9132 * A new command-line option -Wunused-dummy-argument warns about 9133 unused dummy arguments and is included in -Wall. Before, 9134 -Wunused-variable also warned about unused dummy arguments. 9135 * Fortran 2003 support has been extended: 9136 + Improved support for polymorphism between libraries and 9137 programs and for complicated inheritance patterns (cf. 9138 [16]object-oriented programming). 9139 + Experimental support of the ASSOCIATE construct. 9140 + In pointer assignments it is now possible to specify the lower 9141 bounds of the pointer and, for a rank-1 or a simply contiguous 9142 data-target, to remap the bounds. 9143 + Automatic (re)allocation: In intrinsic assignments to 9144 allocatable variables the left-hand side will be automatically 9145 allocated (if unallocated) or reallocated (if the shape or 9146 type parameter is different). To avoid the small performance 9147 penalty, you can use a(:) = ... instead of a = ... for arrays 9148 and character strings - or disable the feature using -std=f95 9149 or -fno-realloc-lhs. 9150 + Deferred type parameter: For scalar allocatable and pointer 9151 variables the character length can be deferred. 9152 + Namelist variables with allocatable and pointer attribute and 9153 nonconstant length type parameter are supported. 9154 * Fortran 2008 support has been extended: 9155 + Experimental [17]coarray support (for one image only, i.e. 9156 num_images() == 1); use the [18]-fcoarray=single flag to 9157 enable it. 9158 + The STOP and the new ERROR STOP statements now support all 9159 constant expressions. 9160 + Support for the CONTIGUOUS attribute. 9161 + Support for ALLOCATE with MOLD. 9162 + Support for the STORAGE_SIZE intrinsic inquiry function. 9163 + Support of the NORM2 and PARITY intrinsic functions. 9164 + The following bit intrinsics were added: POPCNT and POPPAR for 9165 counting the number of 1 bits and returning the parity; BGE, 9166 BGT, BLE, and BLT for bitwise comparisons; DSHIFTL and DSHIFTR 9167 for combined left and right shifts, MASKL and MASKR for simple 9168 left and right justified masks, MERGE_BITS for a bitwise merge 9169 using a mask, SHIFTA, SHIFTL and SHIFTR for shift operations, 9170 and the transformational bit intrinsics IALL, IANY and 9171 IPARITY. 9172 + Support of the EXECUTE_COMMAND_LINE intrinsic subroutine. 9173 + Support for the IMPURE attribute for procedures, which allows 9174 for ELEMENTAL procedures without the restrictions of PURE. 9175 + Null pointers (including NULL()) and not allocated variables 9176 can be used as actual argument to optional non-pointer, 9177 non-allocatable dummy arguments, denoting an absent argument. 9178 + Non-pointer variables with TARGET attribute can be used as 9179 actual argument to POINTER dummies with INTENT(IN) 9180 + Pointers including procedure pointers and those in a derived 9181 type (pointer components) can now be initialized by a target 9182 instead of only by NULL. 9183 + The EXIT statement (with construct-name) can now be used to 9184 leave not only the DO but also the ASSOCIATE, BLOCK, IF, 9185 SELECT CASE and SELECT TYPE constructs. 9186 + Internal procedures can now be used as actual argument. 9187 + The named constants INTEGER_KINDS, LOGICAL_KINDS, REAL_KINDS 9188 and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV 9189 have been added; these arrays contain the supported kind 9190 values for the respective types. 9191 + The module procedures C_SIZEOF of the intrinsic module 9192 ISO_C_BINDINGS and COMPILER_VERSION and COMPILER_OPTIONS of 9193 ISO_FORTRAN_ENV have been implemented. 9194 + Minor changes: obsolescence diagnostics for ENTRY was added 9195 for -std=f2008; a line may start with a semicolon; for 9196 internal and module procedures END can be used instead of END 9197 SUBROUTINE and END FUNCTION; SELECTED_REAL_KIND now also takes 9198 a RADIX argument; intrinsic types are supported for 9199 TYPE(intrinsic-type-spec); multiple type-bound procedures can 9200 be declared in a single PROCEDURE statement; implied-shape 9201 arrays are supported for named constants (PARAMETER). The 9202 transformational, three argument versions of BESSEL_JN and 9203 BESSEL_YN were added - the elemental, two-argument version had 9204 been added in GCC 4.4; note that the transformational 9205 functions use a recurrence algorithm. 9206 9207 Go 9208 9209 Support for the [19]Go programming language has been added to GCC. It 9210 is not enabled by default when you build GCC; use the 9211 --enable-languages configure option to build it. The driver program for 9212 compiling Go code is gccgo. 9213 9214 Go is currently known to work on GNU/Linux and RTEMS. Solaris support 9215 is in progress. It may or may not work on other platforms. 9216 9217 Objective-C and Objective-C++ 9218 9219 * The -fobjc-exceptions flag is now required to enable Objective-C 9220 exception and synchronization syntax (introduced by the keywords 9221 @try, @catch, @finally and @synchronized). 9222 * A number of Objective-C 2.0 features and extensions are now 9223 supported by GCC. These features are enabled by default; you can 9224 disable them by using the new -fobjc-std=objc1 command-line option. 9225 * The Objective-C 2.0 dot-syntax is now supported. It is an 9226 alternative syntax for using getters and setters; object.count is 9227 automatically converted into [object count] or [object setCount: 9228 ...] depending on context; for example if (object.count > 0) is 9229 automatically compiled into the equivalent of if ([object count] > 9230 0) while object.count = 0; is automatically compiled into the 9231 equivalent ot [object setCount: 0];. The dot-syntax can be used 9232 with instance and class objects and with any setters or getters, no 9233 matter if they are part of a declared property or not. 9234 * Objective-C 2.0 declared properties are now supported. They are 9235 declared using the new @property keyword, and are most commonly 9236 used in conjunction with the new Objective-C 2.0 dot-syntax. The 9237 nonatomic, readonly, readwrite, assign, retain, copy, setter and 9238 getter attributes are all supported. Marking declared properties 9239 with __attribute__ ((deprecated)) is supported too. 9240 * The Objective-C 2.0 @synthesize and @dynamic keywords are 9241 supported. @synthesize causes the compiler to automatically 9242 synthesize a declared property, while @dynamic is used to disable 9243 all warnings for a declared property for which no implementation is 9244 provided at compile time. Synthesizing declared properties requires 9245 runtime support in most useful cases; to be able to use it with the 9246 GNU runtime, appropriate helper functions have been added to the 9247 GNU Objective-C runtime ABI, and are implemented by the GNU 9248 Objective-C runtime library shipped with GCC. 9249 * The Objective-C 2.0 fast enumeration syntax is supported in 9250 Objective-C. This is currently not yet available in Objective-C++. 9251 Fast enumeration requires support in the runtime, and such support 9252 has been added to the GNU Objective-C runtime library (shipped with 9253 GCC). 9254 * The Objective-C 2.0 @optional keyword is supported. It allows you 9255 to mark methods or properties in a protocol as optional as opposed 9256 to required. 9257 * The Objective-C 2.0 @package keyword is supported. It has currently 9258 the same effect as the @public keyword. 9259 * Objective-C 2.0 method attributes are supported. Currently the 9260 supported attributes are deprecated, sentinel, noreturn and format. 9261 * Objective-C 2.0 method argument attributes are supported. The most 9262 widely used attribute is unused, to mark an argument as unused in 9263 the implementation. 9264 * Objective-C 2.0 class and protocol attributes are supported. 9265 Currently the only supported attribute is deprecated. 9266 * Objective-C 2.0 class extensions are supported. A class extension 9267 has the same syntax as a category declaration with no category 9268 name, and the methods and properties declared in it are added 9269 directly to the main class. It is mostly used as an alternative to 9270 a category to add methods to a class without advertising them in 9271 the public headers, with the advantage that for class extensions 9272 the compiler checks that all the privately declared methods are 9273 actually implemented. 9274 * As a result of these enhancements, GCC can now be used to build 9275 Objective-C and Objective-C++ software that uses Foundation and 9276 other important system frameworks with the NeXT runtime on Darwin 9 9277 and Darwin 10 (OSX 10.5 and 10.6). 9278 * Many bugs in the compiler have been fixed in this release; in 9279 particular, LTO can now be used when compiling Objective-C and 9280 Objective-C++ and the parser is much more robust in dealing with 9281 invalid code. 9282 9283 Runtime Library (libobjc) 9284 9285 * The GNU Objective-C runtime library now defines the macro 9286 __GNU_LIBOBJC__ (with a value that is increased at every release 9287 where there is any change to the API) in objc/objc.h, making it 9288 easy to determine if the GNU Objective-C runtime library is being 9289 used, and if so, which version. Previous versions of the GNU 9290 Objective-C runtime library (and other Objective-C runtime 9291 libraries such as the Apple one) do not define this macro. 9292 * A new Objective-C 2.0 API, almost identical to the one implemented 9293 by the Apple Objective-C runtime, has been implemented in the GNU 9294 Objective-C runtime library. The new API hides the internals of 9295 most runtime structures but provides a more extensive set of 9296 functions to operate on them. It is much easier, for example, to 9297 create or modify classes at runtime. The new API also makes it 9298 easier to port software from Apple to GNU as almost no changes 9299 should be required. The old API is still supported for backwards 9300 compatibility; including the old objc/objc-api.h header file 9301 automatically selects the old API, while including the new 9302 objc/runtime.h header file automatically selects the new API. 9303 Support for the old API is being phased out and upgrading the 9304 software to use the new API is strongly recommended. To check for 9305 the availability of the new API, the __GNU_LIBOBJC__ macro can be 9306 used as older versions of the GNU Objective-C runtime library, 9307 which do not support the new API, do not define such a macro. 9308 * Runtime support for @synchronized has been added. 9309 * Runtime support for Objective-C 2.0 synthesized property accessors 9310 has been added. 9311 * Runtime support for Objective-C 2.0 fast enumeration has been 9312 added. 9313 9314 New Targets and Target Specific Improvements 9315 9316 ARM 9317 9318 * GCC now supports the Cortex-M4 processor implementing the v7-em 9319 version of the architecture using the option -mcpu=cortex-m4. 9320 * Scheduling descriptions for the Cortex-M4, the Neon and the 9321 floating point units of the Cortex-A9 and a pipeline description 9322 for the Cortex-A5 have been added. 9323 * Synchronization primitives such as __sync_fetch_and_add and friends 9324 are now inlined for supported architectures rather than calling 9325 into a kernel helper function. 9326 * SSA loop prefetching is enabled by default for the Cortex-A9 at 9327 -O3. 9328 * Several improvements were committed to improve code generation for 9329 the ARM architecture including a rewritten implementation for load 9330 and store multiples. 9331 * Several enhancements were committed to improve SIMD code generation 9332 for NEON by adding support for widening instructions, misaligned 9333 loads and stores, vector conditionals and support for 64 bit 9334 arithmetic. 9335 * Support was added for the Faraday cores fa526, fa606te, fa626te, 9336 fmp626te, fmp626 and fa726te and can be used with the respective 9337 names as parameters to the -mcpu= option. 9338 * Basic support was added for Cortex-A15 and is available through 9339 -mcpu=cortex-a15. 9340 * GCC for AAPCS configurations now more closely adheres to the AAPCS 9341 specification by enabling -fstrict-volatile-bitfields by default. 9342 9343 IA-32/x86-64 9344 9345 * The new -fsplit-stack option permits programs to use a 9346 discontiguous stack. This is useful for threaded programs, in that 9347 it is no longer necessary to specify the maximum stack size when 9348 creating a thread. This feature is currently only implemented for 9349 32-bit and 64-bit x86 GNU/Linux targets. 9350 * Support for emitting profiler counter calls before function 9351 prologues. This is enabled via a new command-line option -mfentry. 9352 * Optimization for the Intel Core 2 processors is now available 9353 through the -march=core2 and -mtune=core2 options. 9354 * Support for Intel Core i3/i5/i7 processors is now available through 9355 the -march=corei7 and -mtune=corei7 options. 9356 * Support for Intel Core i3/i5/i7 processors with AVX is now 9357 available through the -march=corei7-avx and -mtune=corei7-avx 9358 options. 9359 * Support for AMD Bobcat (family 14) processors is now available 9360 through the -march=btver1 and -mtune=btver1 options. 9361 * Support for AMD Bulldozer (family 15) processors is now available 9362 through the -march=bdver1 and -mtune=bdver1 options. 9363 * The default setting (when not optimizing for size) for 32-bit 9364 GNU/Linux and Darwin x86 targets has been changed to 9365 -fomit-frame-pointer. The default can be reverted to 9366 -fno-omit-frame-pointer by configuring GCC with the 9367 --enable-frame-pointer configure option. 9368 * Darwin, FreeBSD, Solaris 2, MinGW and Cygwin now all support 9369 __float128 on 32-bit and 64-bit x86 targets. 9370 * AVX floating-point arithmetic can now be enabled by default at 9371 configure time with the new --with-fpmath=avx option. 9372 * The SSA loop prefetching pass is enabled when using -O3 when 9373 optimizing for CPUs where prefetching is beneficial (AMD CPUs newer 9374 than K6). 9375 * Support for TBM (Trailing Bit Manipulation) built-in functions and 9376 code generation is available via -mtbm. 9377 * Support for AMD's BMI (Bit Manipulation) built-in functions and 9378 code generation is available via -mbmi. 9379 9380 MicroBlaze 9381 9382 * Support has been added for the Xilinx MicroBlaze softcore processor 9383 (microblaze-elf) embedded target. This configurable processor is 9384 supported on several Xilinx Spartan and Virtex FPGAs. 9385 9386 MIPS 9387 9388 * GCC now supports the Loongson 3A processor. Its canonical -march= 9389 and -mtune= name is loongson3a. 9390 9391 MN10300 / AM33 9392 9393 * The inline assembly register constraint "A" has been renamed "c". 9394 This constraint is used to select a floating-point register that 9395 can be used as the destination of a multiply-accumulate 9396 instruction. 9397 * New inline assembly register constraints "A" and "D" have been 9398 added. These constraint letters resolve to all general registers 9399 when compiling for AM33, and resolve to address registers only or 9400 data registers only when compiling for MN10300. 9401 * The MDR register is represented in the compiler. One can access the 9402 register via the "z" constraint in inline assembly. It can be 9403 marked as clobbered or used as a local register variable via the 9404 "mdr" name. The compiler uses the RETF instruction if the function 9405 does not modify the MDR register, so it is important that inline 9406 assembly properly annotate any usage of the register. 9407 9408 PowerPC/PowerPC64 9409 9410 * GCC now supports the Applied Micro Titan processor with 9411 -mcpu=titan. 9412 * The -mrecip option has been added, which indicates whether the 9413 reciprocal and reciprocal square root instructions should be used. 9414 * The -mveclibabi=mass option can be used to enable the compiler to 9415 autovectorize mathematical functions using the Mathematical 9416 Acceleration Subsystem library. 9417 * The -msingle-pic-base option has been added, which instructs the 9418 compiler to avoid loading the PIC base register in function 9419 prologues. The PIC base register must be initialized by the runtime 9420 system. 9421 * The -mblock-move-inline-limit option has been added, which enables 9422 the user to control the maximum size of inlined memcpy calls and 9423 similar. 9424 * PowerPC64 GNU/Linux support for applications requiring a large TOC 9425 section has been improved. A new command-line option, 9426 -mcmodel=MODEL, controls this feature; valid values for MODEL are 9427 small, medium, or large. 9428 * The Altivec builtin functions vec_ld and vec_st have been modified 9429 to generate the Altivec memory instructions LVX and STVX, even if 9430 the -mvsx option is used. In the initial GCC 4.5 release, these 9431 builtin functions were changed to generate VSX memory reference 9432 instructions instead of Altivec memory instructions, but there are 9433 differences between the two instructions. If the VSX instruction 9434 set is available, you can now use the new builtin functions 9435 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 9436 instructions. 9437 * The GCC compiler on AIX now defaults to a process layout with a 9438 larger data space allowing larger programs to be compiled. 9439 * The GCC long double type on AIX 6.1 and above has reverted to 64 9440 bit double precision, matching the AIX XL compiler default, because 9441 of missing C99 symbols required by the GCC runtime. 9442 * The default processor scheduling model and tuning for PowerPC64 9443 GNU/Linux and for AIX 6.1 and above now is POWER7. 9444 * Starting with GCC 4.6.1, vectors of type vector long long or vector 9445 long are passed and returned in the same method as other vectors 9446 with the VSX instruction set. Previously the GCC compiler did not 9447 adhere to the ABI for 128-bit vectors with 64-bit integer base 9448 types (PR 48857). This is also fixed in the GCC 4.5.4 release. 9449 9450 S/390, zSeries and System z9/z10, IBM zEnterprise z196 9451 9452 * Support for the zEnterprise z196 processor has been added. When 9453 using the -march=z196 option, the compiler will generate code 9454 making use of the following instruction facilities: 9455 + Conditional load/store 9456 + Distinct-operands 9457 + Floating-point-extension 9458 + Interlocked-access 9459 + Population-count 9460 The -mtune=z196 option avoids the compare and branch instructions 9461 as well as the load address instruction with an index register as 9462 much as possible and performs instruction scheduling appropriate 9463 for the new out-of-order pipeline architecture. 9464 * When using the -m31 -mzarch options the generated code still 9465 conforms to the 32-bit ABI but uses the general purpose registers 9466 as 64-bit registers internally. This requires a Linux kernel saving 9467 the whole 64-bit registers when doing a context switch. Kernels 9468 providing that feature indicate that by the 'highgprs' string in 9469 /proc/cpuinfo. 9470 * The SSA loop prefetching pass is enabled when using -O3. 9471 9472 SPARC 9473 9474 * GCC now supports the LEON series of SPARC V8 processors. The code 9475 generated by the compiler can either be tuned to it by means of the 9476 --with-tune=leon configure option and -mtune=leon compilation 9477 option, or the compiler can be built for the sparc-leon-{elf,linux} 9478 and sparc-leon3-{elf,linux} targets directly. 9479 * GCC has stopped sign/zero-extending parameter registers in the 9480 callee for functions taking parameters with sub-word size in 32-bit 9481 mode, since this is redundant with the specification of the ABI. 9482 GCC has never done so in 64-bit mode since this is also redundant. 9483 * The command-line option -mfix-at697f has been added to enable the 9484 documented workaround for the single erratum of the Atmel AT697F 9485 processor. 9486 9487 Operating Systems 9488 9489 Android 9490 9491 * GCC now supports the Bionic C library and provides a convenient way 9492 of building native libraries and applications for the Android 9493 platform. Refer to the documentation of the -mandroid and -mbionic 9494 options for details on building native code. At the moment, Android 9495 support is enabled only for ARM. 9496 9497 Darwin/Mac OS X 9498 9499 * General 9500 + Initial support for CFString types has been added. 9501 This allows GCC to build projects including the system Core 9502 Foundation frameworks. The GCC Objective-C family supports 9503 CFString "toll-free bridged" as per the Mac OS X system tools. 9504 CFString is also recognized in the context of format 9505 attributes and arguments (see the documentation for format 9506 attributes for limitations). At present, 8-bit character types 9507 are supported. 9508 + Object file size reduction. 9509 The Darwin zeroed memory allocators have been re-written to 9510 make more use of .zerofill sections. For non-debug code, this 9511 can reduce object file size significantly. 9512 + Objective-C family 64-bit support (NeXT ABI 2). 9513 Initial support has been added to support 64-bit Objective-C 9514 code using the Darwin/OS X native (NeXT) runtime. ABI version 9515 2 will be selected automatically when 64-bit code is built. 9516 + Objective-C family 32-bit ABI 1. 9517 For 32-bit code ABI 1 is also now also allowed. At present it 9518 must be selected manually using -fobjc-abi-version=1 where 9519 applicable - i.e. on Darwin 9/10 (OS X 10.5/10.6). 9520 * x86 Architecture 9521 + The -mdynamic-no-pic option has been enabled. 9522 Code supporting -mdynamic-no-pic optimization has been added 9523 and is applicable to -m32 builds. The compiler bootstrap uses 9524 the option where appropriate. 9525 + The default value for -mtune= has been changed. 9526 Since Darwin systems are primarily Xeon, Core-2 or similar the 9527 default tuning has been changed to -mtune=core2. 9528 + Enable 128-bit long double (__float128) support on Darwin. 9529 * PPC Architecture 9530 + Darwin64 ABI. 9531 Several significant bugs have been fixed, such that GCC now 9532 produces code compatible with the Darwin64 PowerPC ABI. 9533 + libffi and boehm-gc. 9534 The Darwin ports of the libffi and boehm-gc libraries have 9535 been upgraded to include a Darwin64 implementation. This means 9536 that powerpc*-*-darwin9 platforms may now, for example, build 9537 Java applications with -m64 enabled. 9538 + Plug-in support has been enabled. 9539 + The -fsection-anchors option is now available although, 9540 presently, not heavily tested. 9541 9542 Solaris 2 9543 9544 New Features 9545 9546 * Support symbol versioning with the Sun linker. 9547 * Allow libstdc++ to leverage full ISO C99 support on Solaris 10+. 9548 * Support thread-local storage (TLS) with the Sun assembler on 9549 Solaris 2/x86. 9550 * Support TLS on Solaris 8/9 if prerequisites are met. 9551 * Support COMDAT group with the GNU assembler and recent Sun linker. 9552 * Support the Sun assembler visibility syntax. 9553 * Default Solaris 2/x86 to -march=pentium4 (Solaris 10+) resp. 9554 -march=pentiumpro (Solaris 8/9). 9555 * Don't use SSE on Solaris 8/9 x86 by default. 9556 * Enable 128-bit long double (__float128) support on Solaris 2/x86. 9557 9558 ABI Change 9559 9560 * Change the ABI for returning 8-byte vectors like __m64 in MMX 9561 registers on Solaris 10+/x86 to match the Sun Studio 12.1+ 9562 compilers. This is an incompatible change. If you use such types, 9563 you must either recompile all your code with the new compiler or 9564 use the new -mvect8-ret-in-mem option to remain compatible with 9565 previous versions of GCC and Sun Studio. 9566 9567 Windows x86/x86_64 9568 9569 * Initial support for decimal floating point. 9570 * Support for the __thiscall calling-convention. 9571 * Support for hot-patchable function prologues via the 9572 ms_hook_prologue attribute for x86_64 in addition to 32-bit x86. 9573 * Improvements of stack-probing and stack-allocation mechanisms. 9574 * Support of push/pop-macro pragma as preprocessor command. 9575 With #pragma push_macro("macro-name") the current definition of 9576 macro-name is saved and can be restored with #pragma 9577 pop_macro("macro-name") to its saved definition. 9578 * Enable 128-bit long double (__float128) support on MinGW and 9579 Cygwin. 9580 9581 Other significant improvements 9582 9583 Installation changes 9584 9585 * An install-strip make target is provided that installs stripped 9586 executables, and may install libraries with unneeded or debugging 9587 sections stripped. 9588 * On Power7 systems, there is a potential problem if you build the 9589 GCC compiler with a host compiler using options that enable the VSX 9590 instruction set generation. If the host compiler has been patched 9591 so that the vec_ld and vec_st builtin functions generate Altivec 9592 memory instructions instead of VSX memory instructions, then you 9593 should be able to build the compiler with VSX instruction 9594 generation. 9595 9596 Changes for GCC Developers 9597 9598 Note: these changes concern developers that develop GCC itself or 9599 software that integrates with GCC, such as plugins, and not the general 9600 GCC users. 9601 * The gengtype utility, which previously was internal to the GCC 9602 build process, has been enchanced to provide GC root information 9603 for plugins as necessary. 9604 * The old GC allocation interface of ggc_alloc and friends was 9605 replaced with a type-safe alternative. 9606 9607 GCC 4.6.1 9608 9609 This is the [20]list of problem reports (PRs) from GCC's bug tracking 9610 system that are known to be fixed in the 4.6.1 release. This list might 9611 not be complete (that is, it is possible that some PRs that have been 9612 fixed are not listed here). 9613 9614 GCC 4.6.2 9615 9616 This is the [21]list of problem reports (PRs) from GCC's bug tracking 9617 system that are known to be fixed in the 4.6.2 release. This list might 9618 not be complete (that is, it is possible that some PRs that have been 9619 fixed are not listed here). 9620 9621 GCC 4.6.3 9622 9623 This is the [22]list of problem reports (PRs) from GCC's bug tracking 9624 system that are known to be fixed in the 4.6.3 release. This list might 9625 not be complete (that is, it is possible that some PRs that have been 9626 fixed are not listed here). 9627 9628 GCC 4.6.4 9629 9630 This is the [23]list of problem reports (PRs) from GCC's bug tracking 9631 system that are known to be fixed in the 4.6.4 release. This list might 9632 not be complete (that is, it is possible that some PRs that have been 9633 fixed are not listed here). 9634 9635 9636 For questions related to the use of GCC, please consult these web 9637 pages and the [24]GCC manuals. If that fails, the 9638 [25]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9639 web pages and the development of GCC are welcome on our developer 9640 list at [26]gcc (a] gcc.gnu.org. All of [27]our lists have public 9641 archives. 9642 9643 Copyright (C) [28]Free Software Foundation, Inc. Verbatim copying and 9644 distribution of this entire article is permitted in any medium, 9645 provided this notice is preserved. 9646 9647 These pages are [29]maintained by the GCC team. Last modified 9648 2019-11-28[30]. 9649 9650 References 9651 9652 1. https://sourceware.org/bugzilla/show_bug.cgi?id=10401 9653 2. http://gcc.gnu.org/gcc-4.5/changes.html 9654 3. http://gcc.gnu.org/gcc-4.5/changes.html#obsoleted 9655 4. http://gcc.gnu.org/gcc-4.6/porting_to.html 9656 5. http://gcc.gnu.org/projects/lto/whopr.pdf 9657 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 9658 7. http://gcc.gnu.org/gcc-4.6/cxx0x_status.html 9659 8. https://gcc.gnu.org/PR43145 9660 9. https://gcc.gnu.org/PR43680 9661 10. https://gcc.gnu.org/PR33558 9662 11. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253 9663 12. https://gcc.gnu.org/onlinedocs/gcc-4.6.4/libstdc++/manual/manual/status.html#status.iso.200x 9664 13. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode.html 9665 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html#debug.races 9666 15. https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html 9667 16. https://gcc.gnu.org/wiki/OOP 9668 17. https://gcc.gnu.org/wiki/Coarray 9669 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcoarray_007d-233 9670 19. https://golang.org/ 9671 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.1 9672 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.2 9673 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.3 9674 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.4 9675 24. https://gcc.gnu.org/onlinedocs/ 9676 25. mailto:gcc-help (a] gcc.gnu.org 9677 26. mailto:gcc (a] gcc.gnu.org 9678 27. https://gcc.gnu.org/lists.html 9679 28. https://www.fsf.org/ 9680 29. https://gcc.gnu.org/about.html 9681 30. http://validator.w3.org/check/referer 9682 ====================================================================== 9683 http://gcc.gnu.org/gcc-4.5/index.html 9684 9685 GCC 4.5 Release Series 9686 9687 (This release series is no longer supported.) 9688 9689 Jul 2, 2012 9690 9691 The [1]GNU project and the GCC developers are pleased to announce the 9692 release of GCC 4.5.4. 9693 9694 This release is a bug-fix release, containing fixes for regressions in 9695 GCC 4.5.3 relative to previous releases of GCC. 9696 9697 Release History 9698 9699 GCC 4.5.4 9700 Jul 2, 2012 ([2]changes) 9701 9702 GCC 4.5.3 9703 Apr 28, 2011 ([3]changes) 9704 9705 GCC 4.5.2 9706 Dec 16, 2010 ([4]changes) 9707 9708 GCC 4.5.1 9709 Jul 31, 2010 ([5]changes) 9710 9711 GCC 4.5.0 9712 April 14, 2010 ([6]changes) 9713 9714 References and Acknowledgements 9715 9716 GCC used to stand for the GNU C Compiler, but since the compiler 9717 supports several other languages aside from C, it now stands for the 9718 GNU Compiler Collection. 9719 9720 A list of [7]successful builds is updated as new information becomes 9721 available. 9722 9723 The GCC developers would like to thank the numerous people that have 9724 contributed new features, improvements, bug fixes, and other changes as 9725 well as test results to GCC. This [8]amazing group of volunteers is 9726 what makes GCC successful. 9727 9728 For additional information about GCC please refer to the [9]GCC project 9729 web site or contact the [10]GCC development mailing list. 9730 9731 To obtain GCC please use [11]our mirror sites or [12]our version 9732 control system. 9733 9734 9735 For questions related to the use of GCC, please consult these web 9736 pages and the [13]GCC manuals. If that fails, the 9737 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 9738 web pages and the development of GCC are welcome on our developer 9739 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 9740 archives. 9741 9742 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 9743 distribution of this entire article is permitted in any medium, 9744 provided this notice is preserved. 9745 9746 These pages are [18]maintained by the GCC team. Last modified 9747 2020-01-14[19]. 9748 9749 References 9750 9751 1. http://www.gnu.org/ 9752 2. http://gcc.gnu.org/gcc-4.5/changes.html 9753 3. http://gcc.gnu.org/gcc-4.5/changes.html 9754 4. http://gcc.gnu.org/gcc-4.5/changes.html 9755 5. http://gcc.gnu.org/gcc-4.5/changes.html 9756 6. http://gcc.gnu.org/gcc-4.5/changes.html 9757 7. http://gcc.gnu.org/gcc-4.5/buildstat.html 9758 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 9759 9. http://gcc.gnu.org/index.html 9760 10. mailto:gcc (a] gcc.gnu.org 9761 11. http://gcc.gnu.org/mirrors.html 9762 12. http://gcc.gnu.org/git.html 9763 13. https://gcc.gnu.org/onlinedocs/ 9764 14. mailto:gcc-help (a] gcc.gnu.org 9765 15. mailto:gcc (a] gcc.gnu.org 9766 16. https://gcc.gnu.org/lists.html 9767 17. https://www.fsf.org/ 9768 18. https://gcc.gnu.org/about.html 9769 19. http://validator.w3.org/check/referer 9770 ====================================================================== 9771 http://gcc.gnu.org/gcc-4.5/changes.html 9772 9773 GCC 4.5 Release Series 9774 Changes, New Features, and Fixes 9775 9776 Caveats 9777 9778 * GCC now requires the [1]MPC library in order to build. See the 9779 [2]prerequisites page for version requirements. 9780 * Support for a number of older systems and recently unmaintained or 9781 untested target ports of GCC has been declared obsolete in GCC 4.5. 9782 Unless there is activity to revive them, the next release of GCC 9783 will have their sources permanently removed. 9784 The following ports for individual systems on particular 9785 architectures have been obsoleted: 9786 + IRIX releases before 6.5 (mips-sgi-irix5*, 9787 mips-sgi-irix6.[0-4]) 9788 + Solaris 7 (*-*-solaris2.7) 9789 + Tru64 UNIX releases before V5.1 (alpha*-dec-osf4*, 9790 alpha-dec-osf5.0*) 9791 + Details for the IRIX, Solaris 7, and Tru64 UNIX obsoletions 9792 can be found in the [3]announcement. 9793 Support for the classic POWER architecture implemented in the 9794 original RIOS and RIOS2 processors of the old IBM RS/6000 product 9795 line has been obsoleted in the rs6000 port. This does not affect 9796 the new generation Power and PowerPC architectures. 9797 * Support has been removed for all the [4]configurations obsoleted in 9798 GCC 4.4. 9799 * Support has been removed for the protoize and unprotoize utilities, 9800 obsoleted in GCC 4.4. 9801 * Support has been removed for tuning for Itanium1 (Merced) variants. 9802 Note that code tuned for Itanium2 should also run correctly on 9803 Itanium1. 9804 * GCC now generates unwind info also for epilogues. DWARF debuginfo 9805 generated by GCC now uses more features of DWARF3 than before, and 9806 also some DWARF4 features. GDB older than 7.0 is not able to handle 9807 either of these, so to debug GCC 4.5 generated binaries or 9808 libraries GDB 7.0 or later is needed. You can disable use of DWARF4 9809 features with the -gdwarf-3 -gstrict-dwarf options, or use 9810 -gdwarf-2 -gstrict-dwarf to restrict GCC to just DWARF2, but 9811 epilogue unwind info is emitted unconditionally whenever unwind 9812 info is emitted. 9813 * On x86 targets, code containing floating-point calculations may run 9814 significantly more slowly when compiled with GCC 4.5 in strict C99 9815 conformance mode than they did with earlier GCC versions. This is 9816 due to stricter standard conformance of the compiler and can be 9817 avoided by using the option -fexcess-precision=fast; also see 9818 [5]below. 9819 * The function attribute noinline no longer prevents GCC from cloning 9820 the function. A new attribute noclone has been introduced for this 9821 purpose. Cloning a function means that it is duplicated and the new 9822 copy is specialized for certain contexts (for example when a 9823 parameter is a known constant). 9824 9825 General Optimizer Improvements 9826 9827 * The -save-temps now takes an optional argument. The -save-temps and 9828 -save-temps=cwd switches write the temporary files in the current 9829 working directory based on the original source file. The 9830 -save-temps=obj switch will write files into the directory 9831 specified with the -o option, and the intermediate filenames are 9832 based on the output file. This will allow the user to get the 9833 compiler intermediate files when doing parallel builds without two 9834 builds of the same filename located in different directories from 9835 interfering with each other. 9836 * Debugging dumps are now created in the same directory as the object 9837 file rather than in the current working directory. This allows the 9838 user to get debugging dumps when doing parallel builds without two 9839 builds of the same filename interfering with each other. 9840 * GCC has been integrated with the MPC library. This allows GCC to 9841 evaluate complex arithmetic at compile time [6]more accurately. It 9842 also allows GCC to evaluate calls to complex built-in math 9843 functions having constant arguments and replace them at compile 9844 time with their mathematically equivalent results. In doing so, GCC 9845 can generate correct results regardless of the math library 9846 implementation or floating point precision of the host platform. 9847 This also allows GCC to generate identical results regardless of 9848 whether one compiles in native or cross-compile configurations to a 9849 particular target. The following built-in functions take advantage 9850 of this new capability: cacos, cacosh, casin, casinh, catan, 9851 catanh, ccos, ccosh, cexp, clog, cpow, csin, csinh, csqrt, ctan, 9852 and ctanh. The float and long double variants of these functions 9853 (e.g. csinf and csinl) are also handled. 9854 * A new link-time optimizer has been added ([7]-flto). When this 9855 option is used, GCC generates a bytecode representation of each 9856 input file and writes it to specially-named sections in each object 9857 file. When the object files are linked together, all the function 9858 bodies are read from these named sections and instantiated as if 9859 they had been part of the same translation unit. This enables 9860 interprocedural optimizations to work across different files (and 9861 even different languages), potentially improving the performance of 9862 the generated code. To use the link-timer optimizer, -flto needs to 9863 be specified at compile time and during the final link. If the 9864 program does not require any symbols to be exported, it is possible 9865 to combine -flto and the experimental [8]-fwhopr with 9866 [9]-fwhole-program to allow the interprocedural optimizers to use 9867 more aggressive assumptions. 9868 * The automatic parallelization pass was enhanced to support 9869 parallelization of outer loops. 9870 * Automatic parallelization can be enabled as part of Graphite. In 9871 addition to -ftree-parallelize-loops=, specify 9872 -floop-parallelize-all to enable the Graphite-based optimization. 9873 * The infrastructure for optimizing based on [10]restrict qualified 9874 pointers has been rewritten and should result in code generation 9875 improvements. Optimizations based on restrict qualified pointers 9876 are now also available when using -fno-strict-aliasing. 9877 * There is a new optimization pass that attempts to change prototype 9878 of functions to avoid unused parameters, pass only relevant parts 9879 of structures and turn arguments passed by reference to arguments 9880 passed by value when possible. It is enabled by -O2 and above as 9881 well as -Os and can be manually invoked using the new command-line 9882 switch -fipa-sra. 9883 * GCC now optimize exception handling code. In particular cleanup 9884 regions that are proved to not have any effect are optimized out. 9885 9886 New Languages and Language specific improvements 9887 9888 All languages 9889 9890 * The -fshow-column option is now on by default. This means error 9891 messages now have a column associated with them. 9892 9893 Ada 9894 9895 * Compilation of programs heavily using discriminated record types 9896 with variant parts has been sped up and generates more compact 9897 code. 9898 * Stack checking now works reasonably well on most plaforms. In some 9899 specific cases, stack overflows may still fail to be detected, but 9900 a compile-time warning will be issued for these cases. 9901 9902 C family 9903 9904 * If a header named in a #include directive is not found, the 9905 compiler exits immediately. This avoids a cascade of errors arising 9906 from declarations expected to be found in that header being 9907 missing. 9908 * A new built-in function __builtin_unreachable() has been added that 9909 tells the compiler that control will never reach that point. It may 9910 be used after asm statements that terminate by transferring control 9911 elsewhere, and in other places that are known to be unreachable. 9912 * The -Wlogical-op option now warns for logical expressions such as 9913 (c == 1 && c == 2) and (c != 1 || c != 2), which are likely to be 9914 mistakes. This option is disabled by default. 9915 * An asm goto feature has been added to allow asm statements that 9916 jump to C labels. 9917 * C++0x raw strings are supported for C++ and for C with -std=gnu99. 9918 * The deprecated attribute now takes an optional string argument, for 9919 example, __attribute__((deprecated("text string"))), that will be 9920 printed together with the deprecation warning. 9921 9922 C 9923 9924 * The -Wenum-compare option, which warns when comparing values of 9925 different enum types, now works for C. It formerly only worked for 9926 C++. This warning is enabled by -Wall. It may be avoided by using a 9927 type cast. 9928 * The -Wcast-qual option now warns about casts which are unsafe in 9929 that they permit const-correctness to be violated without further 9930 warnings. Specifically, it warns about cases where a qualifier is 9931 added when all the lower types are not const. For example, it warns 9932 about a cast from char ** to const char **. 9933 * The -Wc++-compat option is significantly improved. It issues new 9934 warnings for: 9935 + Using C++ reserved operator names as identifiers. 9936 + Conversions to enum types without explicit casts. 9937 + Using va_arg with an enum type. 9938 + Using different enum types in the two branches of ?:. 9939 + Using ++ or -- on a variable of enum type. 9940 + Using the same name as both a struct, union or enum tag and a 9941 typedef, unless the typedef refers to the tagged type itself. 9942 + Using a struct, union, or enum which is defined within another 9943 struct or union. 9944 + A struct field defined using a typedef if there is a field in 9945 the struct, or an enclosing struct, whose name is the typedef 9946 name. 9947 + Duplicate definitions at file scope. 9948 + Uninitialized const variables. 9949 + A global variable with an anonymous struct, union, or enum 9950 type. 9951 + Using a string constant to initialize a char array whose size 9952 is the length of the string. 9953 * The new -Wjump-misses-init option warns about cases where a goto or 9954 switch skips the initialization of a variable. This sort of branch 9955 is an error in C++ but not in C. This warning is enabled by 9956 -Wc++-compat. 9957 * GCC now ensures that a C99-conforming <stdint.h> is present on most 9958 targets, and uses information about the types in this header to 9959 implement the Fortran bindings to those types. GCC does not ensure 9960 the presence of such a header, and does not implement the Fortran 9961 bindings, on the following targets: NetBSD, VxWorks, VMS, 9962 SymbianOS, WinCE, LynxOS, Netware, QNX, Interix, TPF. 9963 * GCC now implements C90- and C99-conforming rules for constant 9964 expressions. This may cause warnings or errors for some code using 9965 expressions that can be folded to a constant but are not constant 9966 expressions as defined by ISO C. 9967 * All known target-independent C90 and C90 Amendment 1 conformance 9968 bugs, and all known target-independent C99 conformance bugs not 9969 related to floating point or extended identifiers, have been fixed. 9970 * The C decimal floating point support now includes support for the 9971 FLOAT_CONST_DECIMAL64 pragma. 9972 * The named address space feature from ISO/IEC TR 18037 is now 9973 supported. This is currently only implemented for the SPU 9974 processor. 9975 9976 C++ 9977 9978 * Improved [11]experimental support for the upcoming C++0x ISO C++ 9979 standard, including support for raw strings, lambda expressions and 9980 explicit type conversion operators. 9981 * When printing the name of a class template specialization, G++ will 9982 now omit any template arguments which come from default template 9983 arguments. This behavior (and the pretty-printing of function 9984 template specializations as template signature and arguments) can 9985 be disabled with the -fno-pretty-templates option. 9986 * Access control is now applied to typedef names used in a template, 9987 which may cause G++ to reject some ill-formed code that was 9988 accepted by earlier releases. The -fno-access-control option can be 9989 used as a temporary workaround until the code is corrected. 9990 * Compilation time for code that uses templates should now scale 9991 linearly with the number of instantiations rather than 9992 quadratically, as template instantiations are now looked up using 9993 hash tables. 9994 * Declarations of functions that look like builtin declarations of 9995 library functions are only considered to be redeclarations if they 9996 are declared with extern "C". This may cause problems with code 9997 that omits extern "C" on hand-written declarations of C library 9998 functions such as abort or memcpy. Such code is ill-formed, but was 9999 accepted by earlier releases. 10000 * Diagnostics that used to complain about passing non-POD types to 10001 ... or jumping past the declaration of a non-POD variable now check 10002 for triviality rather than PODness, as per C++0x. 10003 * In C++0x mode local and anonymous classes are now allowed as 10004 template arguments, and in declarations of variables and functions 10005 with linkage, so long as any such declaration that is used is also 10006 defined ([12]DR 757). 10007 * Labels may now have attributes, as has been permitted for a while 10008 in C. This is only permitted when the label definition and the 10009 attribute specifier is followed by a semicolon--i.e., the label 10010 applies to an empty statement. The only useful attribute for a 10011 label is unused. 10012 * G++ now implements [13]DR 176. Previously G++ did not support using 10013 the injected-class-name of a template base class as a type name, 10014 and lookup of the name found the declaration of the template in the 10015 enclosing scope. Now lookup of the name finds the 10016 injected-class-name, which can be used either as a type or as a 10017 template, depending on whether or not the name is followed by a 10018 template argument list. As a result of this change, some code that 10019 was previously accepted may be ill-formed because 10020 1. The injected-class-name is not accessible because it's from a 10021 private base, or 10022 2. The injected-class-name cannot be used as an argument for a 10023 template template parameter. 10024 In either of these cases, the code can be fixed by adding a 10025 nested-name-specifier to explicitly name the template. The first 10026 can be worked around with -fno-access-control; the second is only 10027 rejected with -pedantic. 10028 * A new standard mangling for SIMD vector types has been added, to 10029 avoid name clashes on systems with vectors of varying length. By 10030 default the compiler still uses the old mangling, but emits aliases 10031 with the new mangling on targets that support strong aliases. Users 10032 can switch over entirely to the new mangling with -fabi-version=4 10033 or -fabi-version=0. -Wabi will now warn about code that uses the 10034 old mangling. 10035 * The command-line option -ftemplate-depth-N is now written as 10036 -ftemplate-depth=N and the old form is deprecated. 10037 * Conversions between NULL and non-pointer types are now warned by 10038 default. The new option -Wno-conversion-null disables these 10039 warnings. Previously these warnings were only available when using 10040 -Wconversion explicitly. 10041 10042 Runtime Library (libstdc++) 10043 10044 * Improved experimental support for the upcoming ISO C++ standard, 10045 C++0x, including: 10046 + Support for <future>, <functional>, and <random>. 10047 + Existing facilities now exploit explicit operators and the 10048 newly implemented core C++0x features. 10049 + The header <cstdatomic> has been renamed to <atomic>. 10050 * An experimental [14]profile mode has been added. This is an 10051 implementation of many C++ standard library constructs with an 10052 additional analysis layer that gives performance improvement advice 10053 based on recognition of suboptimal usage patterns. For example, 10054 #include <vector> 10055 int main() 10056 { 10057 std::vector<int> v; 10058 for (int k = 0; k < 1024; ++k) 10059 v.insert(v.begin(), k); 10060 } 10061 10062 When instrumented via the profile mode, can return suggestions 10063 about the initial size and choice of the container used as follows: 10064 vector-to-list: improvement = 5: call stack = 0x804842c ... 10065 : advice = change std::vector to std::list 10066 vector-size: improvement = 3: call stack = 0x804842c ... 10067 : advice = change initial container size from 0 to 1024 10068 10069 These constructs can be substituted for the normal libstdc++ 10070 constructs on a piecemeal basis, or all existing components can be 10071 transformed via the -D_GLIBCXX_PROFILE macro. 10072 * [15]Support for decimal floating-point arithmetic (aka ISO C++ TR 10073 24733) has been added. This support is in header file 10074 <decimal/decimal>, uses namespace std::decimal, and includes 10075 classes decimal32, decimal64, and decimal128. 10076 * Sources have been audited for application of function attributes 10077 nothrow, const, pure, and noreturn. 10078 * Python pretty-printers have been added for many standard library 10079 components that simplify the internal representation and present a 10080 more intuitive view of components when used with 10081 appropriately-advanced versions of GDB. For more information, 10082 please consult the more [16]detailed description. 10083 * The default behavior for comparing typeinfo names has changed, so 10084 in <typeinfo>, __GXX_MERGED_TYPEINFO_NAMES now defaults to zero. 10085 * The new -static-libstdc++ option directs g++ to link the C++ 10086 library statically, even if the default would normally be to link 10087 it dynamically. 10088 10089 Fortran 10090 10091 * The COMMON default padding has been changed - instead of adding the 10092 padding before a variable it is now added afterwards, which 10093 increases the compatibility with other vendors and helps to obtain 10094 the correct output in some cases. Cf. also the -falign-commons 10095 option ([17]added in 4.4). 10096 * The -finit-real= option now also supports the value snan for 10097 signaling not-a-number; to be effective, one additionally needs to 10098 enable trapping (e.g. via -ffpe-trap=). Note: Compile-time 10099 optimizations can turn a signaling NaN into a quiet one. 10100 * The new option -fcheck= has been added with the options bounds, 10101 array-temps, do, pointer, and recursive. The bounds and array-temps 10102 options are equivalent to -fbounds-check and 10103 -fcheck-array-temporaries. The do option checks for invalid 10104 modification of loop iteration variables, and the recursive option 10105 tests for recursive calls to subroutines/functions which are not 10106 marked as recursive. With pointer pointer association checks in 10107 calls are performed; however, neither undefined pointers nor 10108 pointers in expressions are handled. Using -fcheck=all enables all 10109 these run-time checks. 10110 * The run-time checking -fcheck=bounds now warns about invalid string 10111 lengths of character dummy arguments. Additionally, more 10112 compile-time checks have been added. 10113 * The new option [18]-fno-protect-parens has been added; if set, the 10114 compiler may reorder REAL and COMPLEX expressions without regard to 10115 parentheses. 10116 * GNU Fortran no longer links against libgfortranbegin. As before, 10117 MAIN__ (assembler symbol name) is the actual Fortran main program, 10118 which is invoked by the main function. However, main is now 10119 generated and put in the same object file as MAIN__. For the time 10120 being, libgfortranbegin still exists for backward compatibility. 10121 For details see the new [19]Mixed-Language Programming chapter in 10122 the manual. 10123 * The I/O library was restructured for performance and cleaner code. 10124 * Array assignments and WHERE are now run in parallel when OpenMP's 10125 WORKSHARE is used. 10126 * The experimental option -fwhole-file was added. The option allows 10127 whole-file checking of procedure arguments and allows for better 10128 optimizations. It can also be used with -fwhole-program, which is 10129 now also supported in gfortran. 10130 * More Fortran 2003 and Fortran 2008 mathematical functions can now 10131 be used as initialization expressions. 10132 * Some extended attributes such as STDCALL are now supported via the 10133 [20]GCC$ compiler directive. 10134 * For Fortran 77 compatibility: If -fno-sign-zero is used, the SIGN 10135 intrinsic behaves now as if zero were always positive. 10136 * For legacy compatibiliy: On Cygwin and MinGW, the special files 10137 CONOUT$ and CONIN$ (and CONERR$ which maps to CONOUT$) are now 10138 supported. 10139 * Fortran 2003 support has been extended: 10140 + Procedure-pointer function results and procedure-pointer 10141 components (including PASS), 10142 + allocatable scalars (experimental), 10143 + DEFERRED type-bound procedures, 10144 + the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements 10145 have been implemented. 10146 + The ALLOCATE statement supports type-specs and the SOURCE= 10147 argument. 10148 + OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC 10149 type-bound procedure (i.e. as type-bound operators). 10150 + Rounding (ROUND=, RZ, ...) for output is now supported. 10151 + The INT_FAST{8,16,32,64,128}_T kind type parameters of the 10152 intrinsic module ISO_C_BINDING are now supported, except for 10153 the targets listed above as ones where GCC does not have 10154 <stdint.h> type information. 10155 + Extensible derived types with type-bound procedure or 10156 procedure pointer with PASS attribute now have to use CLASS in 10157 line with the Fortran 2003 standard; the workaround to use 10158 TYPE is no longer supported. 10159 + [21]Experimental, incomplete support for polymorphism, 10160 including CLASS, SELECT TYPE and dynamic dispatch of 10161 type-bound procedure calls. Some features do not work yet such 10162 as unlimited polymorphism (CLASS(*)). 10163 * Fortran 2008 support has been extended: 10164 + The OPEN statement now supports the NEWUNIT= option, which 10165 returns a unique file unit, thus preventing inadvertent use of 10166 the same unit in different parts of the program. 10167 + Support for unlimited format items has been added. 10168 + The INT{8,16,32} and REAL{32,64,128} kind type parameters of 10169 the intrinsic module ISO_FORTRAN_ENV are now supported. 10170 + Using complex arguments with TAN, SINH, COSH, TANH, ASIN, 10171 ACOS, and ATAN is now possible; the functions ASINH, ACOSH, 10172 and ATANH have been added (for real and complex arguments) and 10173 ATAN(Y,X) is now an alias for ATAN2(Y,X). 10174 + The BLOCK construct has been implemented. 10175 10176 New Targets and Target Specific Improvements 10177 10178 AIX 10179 10180 * Full cross-toolchain support now available with GNU Binutils 10181 10182 ARM 10183 10184 * GCC now supports the Cortex-M0 and Cortex-A5 processors. 10185 * GCC now supports the ARM v7E-M architecture. 10186 * GCC now supports VFPv4-based FPUs and FPUs with 10187 single-precision-only VFP. 10188 * GCC has many improvements to optimization for other ARM processors, 10189 including scheduling support for the integer pipeline on Cortex-A9. 10190 * GCC now supports the IEEE 754-2008 half-precision floating-point 10191 type, and a variant ARM-specific half-precision type. This type is 10192 specified using __fp16, with the layout determined by 10193 -mfp16-format. With appropriate -mfpu options, the Cortex-A9 and 10194 VFPv4 half-precision instructions will be used. 10195 * GCC now supports the variant of AAPCS that uses VFP registers for 10196 parameter passing and return values. 10197 10198 AVR 10199 10200 * The -mno-tablejump option has been removed because it has the same 10201 effect as the -fno-jump-tables option. 10202 * Added support for these new AVR devices: 10203 + ATmega8U2 10204 + ATmega16U2 10205 + ATmega32U2 10206 10207 IA-32/x86-64 10208 10209 * GCC now will set the default for -march= based on the configure 10210 target. 10211 * GCC now supports handling floating-point excess precision arising 10212 from use of the x87 floating-point unit in a way that conforms to 10213 ISO C99. This is enabled with -fexcess-precision=standard and with 10214 standards conformance options such as -std=c99, and may be disabled 10215 using -fexcess-precision=fast. 10216 * Support for the Intel Atom processor is now available through the 10217 -march=atom and -mtune=atom options. 10218 * A new -mcrc32 option is now available to enable crc32 intrinsics. 10219 * A new -mmovbe option is now available to enable GCC to use the 10220 movbe instruction to implement __builtin_bswap32 and 10221 __builtin_bswap64. 10222 * SSE math now can be enabled by default at configure time with the 10223 new --with-fpmath=sse option. 10224 * There is a new intrinsic header file, <x86intrin.h>. It should be 10225 included before using any IA-32/x86-64 intrinsics. 10226 * Support for the XOP, FMA4, and LWP instruction sets for the AMD 10227 Orochi processors are now available with the -mxop, -mfma4, and 10228 -mlwp options. 10229 * The -mabm option enables GCC to use the popcnt and lzcnt 10230 instructions on AMD processors. 10231 * The -mpopcnt option enables GCC to use the popcnt instructions on 10232 both AMD and Intel processors. 10233 10234 M68K/ColdFire 10235 10236 * GCC now supports ColdFire 51xx, 5221x, 5225x, 52274, 52277, 5301x 10237 and 5441x devices. 10238 * GCC now supports thread-local storage (TLS) on M68K and ColdFire 10239 processors. 10240 10241 MeP 10242 10243 Support has been added for the Toshiba Media embedded Processor (MeP, 10244 or mep-elf) embedded target. 10245 10246 MIPS 10247 10248 * GCC now supports MIPS 1004K processors. 10249 * GCC can now be configured with options --with-arch-32, 10250 --with-arch-64, --with-tune-32 and --with-tune-64 to control the 10251 default optimization separately for 32-bit and 64-bit modes. 10252 * MIPS targets now support an alternative _mcount interface, in which 10253 register $12 points to the function's save slot for register $31. 10254 This interface is selected by the -mcount-ra-address option; see 10255 the documentation for more details. 10256 * GNU/Linux targets can now generate read-only .eh_frame sections. 10257 This optimization requires GNU binutils 2.20 or above, and is only 10258 available if GCC is configured with a suitable version of binutils. 10259 * GNU/Linux targets can now attach special relocations to indirect 10260 calls, so that the linker can turn them into direct jumps or 10261 branches. This optimization requires GNU binutils 2.20 or later, 10262 and is automatically selected if GCC is configured with an 10263 appropriate version of binutils. It can be explicitly enabled or 10264 disabled using the -mrelax-pic-calls command-line option. 10265 * GCC now generates more heavily-optimized atomic operations on 10266 Octeon processors. 10267 * MIPS targets now support the -fstack-protector option. 10268 * GCC now supports an -msynci option, which specifies that synci is 10269 enough to flush the instruction cache, without help from the 10270 operating system. GCC uses this information to optimize 10271 automatically-generated cache flush operations, such as those used 10272 for nested functions in C. There is also a --with-synci 10273 configure-time option, which makes -msynci the default. 10274 * GCC supports four new function attributes for interrupt handlers: 10275 interrupt, use_shadow_register_set, keep_interrupts_masked and 10276 use_debug_exception_return. See the documentation for more details 10277 about these attributes. 10278 10279 RS/6000 (POWER/PowerPC) 10280 10281 * GCC now supports the Power ISA 2.06, which includes the VSX 10282 instructions that add vector 64-bit floating point support, new 10283 population count instructions, and conversions between floating 10284 point and unsigned types. 10285 * Support for the power7 processor is now available through the 10286 -mcpu=power7 and -mtune=power7. 10287 * GCC will now vectorize loops that contain simple math functions 10288 like copysign when generating code for altivec or VSX targets. 10289 * Support for the A2 processor is now available through the -mcpu=a2 10290 and -mtune=a2 options. 10291 * Support for the 476 processor is now available through the 10292 -mcpu={476,476fp} and -mtune={476,476fp} options. 10293 * Support for the e500mc64 processor is now available through the 10294 -mcpu=e500mc64 and -mtune=e500mc64 options. 10295 * GCC can now be configured with options --with-cpu-32, 10296 --with-cpu-64, --with-tune-32 and --with-tune-64 to control the 10297 default optimization separately for 32-bit and 64-bit modes. 10298 * Starting with GCC 4.5.4, vectors of type vector long long or vector 10299 long are passed and returned in the same method as other vectors 10300 with the VSX instruction set. Previously the GCC compiler did not 10301 adhere to the ABI for 128-bit vectors with 64-bit integer base 10302 types (PR 48857). This is also fixed in the GCC 4.6.1 release. 10303 10304 RX 10305 10306 Support has been added for the Renesas RX Processor (rx-elf) target. 10307 10308 Operating Systems 10309 10310 Windows (Cygwin and MinGW) 10311 10312 * GCC now installs all the major language runtime libraries as DLLs 10313 when configured with the --enable-shared option. 10314 * GCC now makes use of the new support for aligned common variables 10315 in versions of binutils >= 2.20 to fix bugs in the support for SSE 10316 data types. 10317 * Improvements to the libffi support library increase the reliability 10318 of code generated by GCJ on all Windows platforms. Libgcj is 10319 enabled by default for the first time. 10320 * Libtool improvements simplify installation by placing the generated 10321 DLLs in the correct binaries directory. 10322 * Numerous other minor bugfixes and improvements, and substantial 10323 enhancements to the Fortran language support library. 10324 10325 > 10326 10327 Other significant improvements 10328 10329 Plugins 10330 10331 * It is now possible to extend the compiler without having to modify 10332 its source code. A new option -fplugin=file.so tells GCC to load 10333 the shared object file.so and execute it as part of the compiler. 10334 The internal documentation describes the details on how plugins can 10335 interact with the compiler. 10336 10337 Installation changes 10338 10339 * The move to newer autotools changed default installation 10340 directories and switches to control them: The --with-datarootdir, 10341 --with-docdir, --with-pdfdir, and --with-htmldir switches are not 10342 used any more. Instead, you can now use --datarootdir, --docdir, 10343 --htmldir, and --pdfdir. The default installation directories have 10344 changed as follows according to the GNU Coding Standards: 10345 10346 datarootdir read-only architecture-independent data root [PREFIX/share] 10347 localedir locale-specific message catalogs [DATAROOTDIR/locale] 10348 docdir documentation root [DATAROOTDIR/doc/PACKAGE] 10349 htmldir html documentation [DOCDIR] 10350 dvidir dvi documentation [DOCDIR] 10351 pdfdir pdf documentation [DOCDIR] 10352 psdir ps documentation [DOCDIR] 10353 The following variables have new default values: 10354 10355 datadir read-only architecture-independent data [DATAROOTDIR] 10356 infodir info documentation [DATAROOTDIR/info] 10357 mandir man documentation [DATAROOTDIR/man] 10358 10359 GCC 4.5.1 10360 10361 This is the [22]list of problem reports (PRs) from GCC's bug tracking 10362 system that are known to be fixed in the 4.5.1 release. This list might 10363 not be complete (that is, it is possible that some PRs that have been 10364 fixed are not listed here). 10365 10366 All languages 10367 10368 * GCC's new link-time optimizer ([23]-flto) now also works on a few 10369 non-ELF targets: 10370 + Cygwin (*-cygwin*) 10371 + MinGW (*-mingw*) 10372 + Darwin on x86-64 (x86_64-apple-darwin*) 10373 LTO is not enabled by default for these targets. To enable LTO, you 10374 should configure with the --enable-lto option. 10375 10376 GCC 4.5.2 10377 10378 This is the [24]list of problem reports (PRs) from GCC's bug tracking 10379 system that are known to be fixed in the 4.5.2 release. This list might 10380 not be complete (that is, it is possible that some PRs that have been 10381 fixed are not listed here). 10382 10383 GCC 4.5.3 10384 10385 This is the [25]list of problem reports (PRs) from GCC's bug tracking 10386 system that are known to be fixed in the 4.5.3 release. This list might 10387 not be complete (that is, it is possible that some PRs that have been 10388 fixed are not listed here). 10389 10390 On the PowerPC compiler, the Altivec builtin functions vec_ld and 10391 vec_st have been modified to generate the Altivec memory instructions 10392 LVX and STVX, even if the -mvsx option is used. In the initial GCC 4.5 10393 release, these builtin functions were changed to generate VSX memory 10394 reference instructions instead of Altivec memory instructions, but 10395 there are differences between the two instructions. If the VSX 10396 instruction set is available, you can now use the new builtin functions 10397 vec_vsx_ld and vec_vsx_st which always generates the VSX memory 10398 instructions. 10399 10400 GCC 4.5.4 10401 10402 This is the [26]list of problem reports (PRs) from GCC's bug tracking 10403 system that are known to be fixed in the 4.5.4 release. This list might 10404 not be complete (that is, it is possible that some PRs that have been 10405 fixed are not listed here). 10406 10407 10408 For questions related to the use of GCC, please consult these web 10409 pages and the [27]GCC manuals. If that fails, the 10410 [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10411 web pages and the development of GCC are welcome on our developer 10412 list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public 10413 archives. 10414 10415 Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and 10416 distribution of this entire article is permitted in any medium, 10417 provided this notice is preserved. 10418 10419 These pages are [32]maintained by the GCC team. Last modified 10420 2019-11-28[33]. 10421 10422 References 10423 10424 1. http://www.multiprecision.org/mpc/ 10425 2. https://gcc.gnu.org/install/prerequisites.html 10426 3. https://gcc.gnu.org/ml/gcc/2010-01/msg00510.html 10427 4. http://gcc.gnu.org/gcc-4.4/changes.html#obsoleted 10428 5. http://gcc.gnu.org/gcc-4.5/changes.html#x86 10429 6. https://gcc.gnu.org/PR30789 10430 7. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 10431 8. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhopr-802 10432 9. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhole-program-800 10433 10. https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html 10434 11. http://gcc.gnu.org/gcc-4.5/cxx0x_status.html 10435 12. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#757 10436 13. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#176 10437 14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/profile_mode.html 10438 15. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.tr24733 10439 16. https://sourceware.org/gdb/wiki/STLSupport 10440 17. http://gcc.gnu.org/gcc-4.4/changes.html 10441 18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html 10442 19. https://gcc.gnu.org/onlinedocs/gfortran/Mixed-Language-Programming.html 10443 20. https://gcc.gnu.org/onlinedocs/gfortran/GNU-Fortran-Compiler-Directives.html 10444 21. https://gcc.gnu.org/wiki/OOP 10445 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.1 10446 23. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801 10447 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.2 10448 25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.3 10449 26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.4 10450 27. https://gcc.gnu.org/onlinedocs/ 10451 28. mailto:gcc-help (a] gcc.gnu.org 10452 29. mailto:gcc (a] gcc.gnu.org 10453 30. https://gcc.gnu.org/lists.html 10454 31. https://www.fsf.org/ 10455 32. https://gcc.gnu.org/about.html 10456 33. http://validator.w3.org/check/referer 10457 ====================================================================== 10458 http://gcc.gnu.org/gcc-4.4/index.html 10459 10460 GCC 4.4 Release Series 10461 10462 This release series is no longer maintained. 10463 10464 March 13, 2012 10465 10466 The [1]GNU project and the GCC developers are pleased to announce the 10467 release of GCC 4.4.7. 10468 10469 This release is a bug-fix release, containing fixes for regressions in 10470 GCC 4.4.6 relative to previous releases of GCC. 10471 10472 Release History 10473 10474 GCC 4.4.7 10475 March 13, 2012 ([2]changes) 10476 10477 GCC 4.4.6 10478 April 16, 2011 ([3]changes) 10479 10480 GCC 4.4.5 10481 October 1, 2010 ([4]changes) 10482 10483 GCC 4.4.4 10484 April 29, 2010 ([5]changes) 10485 10486 GCC 4.4.3 10487 January 21, 2010 ([6]changes) 10488 10489 GCC 4.4.2 10490 October 15, 2009 ([7]changes) 10491 10492 GCC 4.4.1 10493 July 22, 2009 ([8]changes) 10494 10495 GCC 4.4.0 10496 April 21, 2009 ([9]changes) 10497 10498 References and Acknowledgements 10499 10500 GCC used to stand for the GNU C Compiler, but since the compiler 10501 supports several other languages aside from C, it now stands for the 10502 GNU Compiler Collection. 10503 10504 A list of [10]successful builds is updated as new information becomes 10505 available. 10506 10507 The GCC developers would like to thank the numerous people that have 10508 contributed new features, improvements, bug fixes, and other changes as 10509 well as test results to GCC. This [11]amazing group of volunteers is 10510 what makes GCC successful. 10511 10512 For additional information about GCC please refer to the [12]GCC 10513 project web site or contact the [13]GCC development mailing list. 10514 10515 To obtain GCC please use [14]our mirror sites or [15]our version 10516 control system. 10517 10518 10519 For questions related to the use of GCC, please consult these web 10520 pages and the [16]GCC manuals. If that fails, the 10521 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 10522 web pages and the development of GCC are welcome on our developer 10523 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 10524 archives. 10525 10526 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 10527 distribution of this entire article is permitted in any medium, 10528 provided this notice is preserved. 10529 10530 These pages are [21]maintained by the GCC team. Last modified 10531 2020-01-14[22]. 10532 10533 References 10534 10535 1. http://www.gnu.org/ 10536 2. http://gcc.gnu.org/gcc-4.4/changes.html 10537 3. http://gcc.gnu.org/gcc-4.4/changes.html 10538 4. http://gcc.gnu.org/gcc-4.4/changes.html 10539 5. http://gcc.gnu.org/gcc-4.4/changes.html 10540 6. http://gcc.gnu.org/gcc-4.4/changes.html 10541 7. http://gcc.gnu.org/gcc-4.4/changes.html 10542 8. http://gcc.gnu.org/gcc-4.4/changes.html 10543 9. http://gcc.gnu.org/gcc-4.4/changes.html 10544 10. http://gcc.gnu.org/gcc-4.4/buildstat.html 10545 11. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 10546 12. http://gcc.gnu.org/index.html 10547 13. mailto:gcc (a] gcc.gnu.org 10548 14. http://gcc.gnu.org/mirrors.html 10549 15. http://gcc.gnu.org/git.html 10550 16. https://gcc.gnu.org/onlinedocs/ 10551 17. mailto:gcc-help (a] gcc.gnu.org 10552 18. mailto:gcc (a] gcc.gnu.org 10553 19. https://gcc.gnu.org/lists.html 10554 20. https://www.fsf.org/ 10555 21. https://gcc.gnu.org/about.html 10556 22. http://validator.w3.org/check/referer 10557 ====================================================================== 10558 http://gcc.gnu.org/gcc-4.4/changes.html 10559 10560 GCC 4.4 Release Series 10561 Changes, New Features, and Fixes 10562 10563 The latest release in the 4.4 release series is [1]GCC 4.4.7. 10564 10565 Caveats 10566 10567 * __builtin_stdarg_start has been completely removed from GCC. 10568 Support for <varargs.h> had been deprecated since GCC 4.0. Use 10569 __builtin_va_start as a replacement. 10570 * Some of the errors issued by the C++ front end that could be 10571 downgraded to warnings in previous releases by using -fpermissive 10572 are now warnings by default. They can be converted into errors by 10573 using -pedantic-errors. 10574 * Use of the cpp assertion extension will now emit a warning when 10575 -Wdeprecated or -pedantic is used. This extension has been 10576 deprecated for many years, but never warned about. 10577 * Packed bit-fields of type char were not properly bit-packed on many 10578 targets prior to GCC 4.4. On these targets, the fix in GCC 4.4 10579 causes an ABI change. For example there is no longer a 4-bit 10580 padding between field a and b in this structure: 10581 struct foo 10582 { 10583 char a:4; 10584 char b:8; 10585 } __attribute__ ((packed)); 10586 There is a new warning to help identify fields that are affected: 10587 foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4 10588 The warning can be disabled with -Wno-packed-bitfield-compat. 10589 * On ARM EABI targets, the C++ mangling of the va_list type has been 10590 changed to conform to the current revision of the EABI. This does 10591 not affect the libstdc++ library included with GCC. 10592 * The SCOUNT and POS bits of the MIPS DSP control register are now 10593 treated as global. Previous versions of GCC treated these fields as 10594 call-clobbered instead. 10595 * The MIPS port no longer recognizes the h asm constraint. It was 10596 necessary to remove this constraint in order to avoid generating 10597 unpredictable code sequences. 10598 One of the main uses of the h constraint was to extract the high 10599 part of a multiplication on 64-bit targets. For example: 10600 asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y)); 10601 You can now achieve the same effect using 128-bit types: 10602 typedef unsigned int uint128_t __attribute__((mode(TI))); 10603 result = ((uint128_t) x * y) >> 64; 10604 The second sequence is better in many ways. For example, if x and y 10605 are constants, the compiler can perform the multiplication at 10606 compile time. If x and y are not constants, the compiler can 10607 schedule the runtime multiplication better than it can schedule an 10608 asm statement. 10609 * Support for a number of older systems and recently unmaintained or 10610 untested target ports of GCC has been declared obsolete in GCC 4.4. 10611 Unless there is activity to revive them, the next release of GCC 10612 will have their sources permanently removed. 10613 The following ports for individual systems on particular 10614 architectures have been obsoleted: 10615 + Generic a.out on IA32 and m68k (i[34567]86-*-aout*, 10616 m68k-*-aout*) 10617 + Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*, 10618 armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*, 10619 sh-*-*). This does not affect other more specific targets 10620 using the COFF object format on those architectures, or the 10621 more specific H8300 and SH targets (h8300-*-rtems*, 10622 h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*, 10623 sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks). 10624 + 2BSD on PDP-11 (pdp11-*-bsd) 10625 + AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*, 10626 powerpc-ibm-aix4.[12]*) 10627 + Tuning support for Itanium1 (Merced) variants. Note that code 10628 tuned for Itanium2 should also run correctly on Itanium1. 10629 * The protoize and unprotoize utilities have been obsoleted and will 10630 be removed in GCC 4.5. These utilities have not been installed by 10631 default since GCC 3.0. 10632 * Support has been removed for all the [2]configurations obsoleted in 10633 GCC 4.3. 10634 * Unknown -Wno-* options are now silently ignored by GCC if no other 10635 diagnostics are issued. If other diagnostics are issued, then GCC 10636 warns about the unknown options. 10637 * More information on porting to GCC 4.4 from previous versions of 10638 GCC can be found in the [3]porting guide for this release. 10639 10640 General Optimizer Improvements 10641 10642 * A new command-line switch -findirect-inlining has been added. When 10643 turned on it allows the inliner to also inline indirect calls that 10644 are discovered to have known targets at compile time thanks to 10645 previous inlining. 10646 * A new command-line switch -ftree-switch-conversion has been added. 10647 This new pass turns simple initializations of scalar variables in 10648 switch statements into initializations from a static array, given 10649 that all the values are known at compile time and the ratio between 10650 the new array size and the original switch branches does not exceed 10651 the parameter --param switch-conversion-max-branch-ratio (default 10652 is eight). 10653 * A new command-line switch -ftree-builtin-call-dce has been added. 10654 This optimization eliminates unnecessary calls to certain builtin 10655 functions when the return value is not used, in cases where the 10656 calls can not be eliminated entirely because the function may set 10657 errno. This optimization is on by default at -O2 and above. 10658 * A new command-line switch -fconserve-stack directs the compiler to 10659 minimize stack usage even if it makes the generated code slower. 10660 This affects inlining decisions. 10661 * When the assembler supports it, the compiler will now emit unwind 10662 information using assembler .cfi directives. This makes it possible 10663 to use such directives in inline assembler code. The new option 10664 -fno-dwarf2-cfi-asm directs the compiler to not use .cfi 10665 directives. 10666 * The [4]Graphite branch has been merged. This merge has brought in a 10667 new framework for loop optimizations based on a polyhedral 10668 intermediate representation. These optimizations apply to all the 10669 languages supported by GCC. The following new code transformations 10670 are available in GCC 4.4: 10671 + -floop-interchange performs loop interchange transformations 10672 on loops. Interchanging two nested loops switches the inner 10673 and outer loops. For example, given a loop like: 10674 DO J = 1, M 10675 DO I = 1, N 10676 A(J, I) = A(J, I) * C 10677 ENDDO 10678 ENDDO 10679 10680 loop interchange will transform the loop as if the user had 10681 written: 10682 DO I = 1, N 10683 DO J = 1, M 10684 A(J, I) = A(J, I) * C 10685 ENDDO 10686 ENDDO 10687 10688 which can be beneficial when N is larger than the caches, 10689 because in Fortran, the elements of an array are stored in 10690 memory contiguously by column, and the original loop iterates 10691 over rows, potentially creating at each access a cache miss. 10692 + -floop-strip-mine performs loop strip mining transformations 10693 on loops. Strip mining splits a loop into two nested loops. 10694 The outer loop has strides equal to the strip size and the 10695 inner loop has strides of the original loop within a strip. 10696 For example, given a loop like: 10697 DO I = 1, N 10698 A(I) = A(I) + C 10699 ENDDO 10700 10701 loop strip mining will transform the loop as if the user had 10702 written: 10703 DO II = 1, N, 4 10704 DO I = II, min (II + 3, N) 10705 A(I) = A(I) + C 10706 ENDDO 10707 ENDDO 10708 10709 + -floop-block performs loop blocking transformations on loops. 10710 Blocking strip mines each loop in the loop nest such that the 10711 memory accesses of the element loops fit inside caches. For 10712 example, given a loop like: 10713 DO I = 1, N 10714 DO J = 1, M 10715 A(J, I) = B(I) + C(J) 10716 ENDDO 10717 ENDDO 10718 10719 loop blocking will transform the loop as if the user had 10720 written: 10721 DO II = 1, N, 64 10722 DO JJ = 1, M, 64 10723 DO I = II, min (II + 63, N) 10724 DO J = JJ, min (JJ + 63, M) 10725 A(J, I) = B(I) + C(J) 10726 ENDDO 10727 ENDDO 10728 ENDDO 10729 ENDDO 10730 10731 which can be beneficial when M is larger than the caches, 10732 because the innermost loop will iterate over a smaller amount 10733 of data that can be kept in the caches. 10734 * A new register allocator has replaced the old one. It is called 10735 integrated register allocator (IRA) because coalescing, register 10736 live range splitting, and hard register preferencing are done 10737 on-the-fly during coloring. It also has better integration with the 10738 reload pass. IRA is a regional register allocator which uses modern 10739 Chaitin-Briggs coloring instead of Chow's priority coloring used in 10740 the old register allocator. More info about IRA internals and 10741 options can be found in the GCC manuals. 10742 * A new instruction scheduler and software pipeliner, based on the 10743 selective scheduling approach, has been added. The new pass 10744 performs instruction unification, register renaming, substitution 10745 through register copies, and speculation during scheduling. The 10746 software pipeliner is able to pipeline non-countable loops. The new 10747 pass is targeted at scheduling-eager in-order platforms. In GCC 4.4 10748 it is available for the Intel Itanium platform working by default 10749 as the second scheduling pass (after register allocation) at the 10750 -O3 optimization level. 10751 * When using -fprofile-generate with a multi-threaded program, the 10752 profile counts may be slightly wrong due to race conditions. The 10753 new -fprofile-correction option directs the compiler to apply 10754 heuristics to smooth out the inconsistencies. By default the 10755 compiler will give an error message when it finds an inconsistent 10756 profile. 10757 * The new -fprofile-dir=PATH option permits setting the directory 10758 where profile data files are stored when using -fprofile-generate 10759 and friends, and the directory used when reading profile data files 10760 using -fprofile-use and friends. 10761 10762 New warning options 10763 10764 * The new -Wframe-larger-than=NUMBER option directs GCC to emit a 10765 warning if any stack frame is larger than NUMBER bytes. This may be 10766 used to help ensure that code fits within a limited amount of stack 10767 space. 10768 * The command-line option -Wlarger-than-N is now written as 10769 -Wlarger-than=N and the old form is deprecated. 10770 * The new -Wno-mudflap option disables warnings about constructs 10771 which can not be instrumented when using -fmudflap. 10772 10773 New Languages and Language specific improvements 10774 10775 * Version 3.0 of the OpenMP specification is now supported for the C, 10776 C++, and Fortran compilers. 10777 * New character data types, per [5]TR 19769: New character types in 10778 C, are now supported for the C compiler in -std=gnu99 mode, as 10779 __CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in 10780 -std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too. 10781 10782 C family 10783 10784 * A new optimize attribute was added to allow programmers to change 10785 the optimization level and particular optimization options for an 10786 individual function. You can also change the optimization options 10787 via the GCC optimize pragma for functions defined after the pragma. 10788 The GCC push_options pragma and the GCC pop_options pragma allow 10789 you temporarily save and restore the options used. The GCC 10790 reset_options pragma restores the options to what was specified on 10791 the command line. 10792 * Uninitialized warnings do not require enabling optimization 10793 anymore, that is, -Wuninitialized can be used together with -O0. 10794 Nonetheless, the warnings given by -Wuninitialized will probably be 10795 more accurate if optimization is enabled. 10796 * -Wparentheses now warns about expressions such as (!x | y) and (!x 10797 & y). Using explicit parentheses, such as in ((!x) | y), silences 10798 this warning. 10799 * -Wsequence-point now warns within if, while,do while and for 10800 conditions, and within for begin/end expressions. 10801 * A new option -dU is available to dump definitions of preprocessor 10802 macros that are tested or expanded. 10803 10804 C++ 10805 10806 * [6]Improved experimental support for the upcoming ISO C++ standard, 10807 C++0x. Including support for auto, inline namespaces, generalized 10808 initializer lists, defaulted and deleted functions, new character 10809 types, and scoped enums. 10810 * Those errors that may be downgraded to warnings to build legacy 10811 code now mention -fpermissive when -fdiagnostics-show-option is 10812 enabled. 10813 * -Wconversion now warns if the result of a static_cast to enumeral 10814 type is unspecified because the value is outside the range of the 10815 enumeral type. 10816 * -Wuninitialized now warns if a non-static reference or non-static 10817 const member appears in a class without constructors. 10818 * G++ now properly implements value-initialization, so objects with 10819 an initializer of () and an implicitly defined default constructor 10820 will be zero-initialized before the default constructor is called. 10821 10822 Runtime Library (libstdc++) 10823 10824 * Improved experimental support for the upcoming ISO C++ standard, 10825 C++0x, including: 10826 + Support for <chrono>, <condition_variable>, <cstdatomic>, 10827 <forward_list>, <initializer_list>, <mutex>, <ratio>, 10828 <system_error>, and <thread>. 10829 + unique_ptr, <algorithm> additions, exception propagation, and 10830 support for the new character types in <string> and <limits>. 10831 + Existing facilities now exploit initializer lists, defaulted 10832 and deleted functions, and the newly implemented core C++0x 10833 features. 10834 + Some standard containers are more efficient together with 10835 stateful allocators, i.e., no allocator is constructed on the 10836 fly at element construction time. 10837 * Experimental support for non-standard pointer types in containers. 10838 * The long standing libstdc++/30928 has been fixed for targets 10839 running glibc 2.10 or later. 10840 * As usual, many small and larger bug fixes, in particular quite a 10841 few corner cases in <locale>. 10842 10843 Fortran 10844 10845 * GNU Fortran now employs libcpp directly instead of using cc1 as an 10846 external preprocessor. The [7]-cpp option was added to allow manual 10847 invocation of the preprocessor without relying on filename 10848 extensions. 10849 * The [8]-Warray-temporaries option warns about array temporaries 10850 generated by the compiler, as an aid to optimization. 10851 * The [9]-fcheck-array-temporaries option has been added, printing a 10852 notification at run time, when an array temporary had to be created 10853 for an function argument. Contrary to -Warray-temporaries the 10854 warning is only printed if the array is noncontiguous. 10855 * Improved generation of DWARF debugging symbols 10856 * If using an intrinsic not part of the selected standard (via -std= 10857 and -fall-intrinsics) gfortran will now treat it as if this 10858 procedure were declared EXTERNAL and try to link to a user-supplied 10859 procedure. -Wintrinsics-std will warn whenever this happens. The 10860 now-useless option -Wnonstd-intrinsic was removed. 10861 * The flag -falign-commons has been added to control the alignment of 10862 variables in COMMON blocks, which is enabled by default in line 10863 with previous GCC version. Using -fno-align-commons one can force 10864 commons to be contiguous in memory as required by the Fortran 10865 standard, however, this slows down the memory access. The option 10866 -Walign-commons, which is enabled by default, warns when padding 10867 bytes were added for alignment. The proper solution is to sort the 10868 common objects by decreasing storage size, which avoids the 10869 alignment problems. 10870 * Fortran 2003 support has been extended: 10871 + Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is 10872 now supported (except internal reads from/writes to wide 10873 strings). [10]-fbackslash now supports also \unnnn and 10874 \Unnnnnnnn to enter Unicode characters. 10875 + Asynchronous I/O (implemented as synchronous I/O) and the 10876 decimal=, size=, sign=, pad=, blank=, and delim= specifiers 10877 are now supported in I/O statements. 10878 + Support for Fortran 2003 structure constructors and for array 10879 constructor with typespec has been added. 10880 + Procedure Pointers (but not yet as component in derived types 10881 and as function results) are now supported. 10882 + Abstract types, type extension, and type-bound procedures 10883 (both PROCEDURE and GENERIC but not as operators). Note: As 10884 CLASS/polymorphyic types are not implemented, type-bound 10885 procedures with PASS accept as non-standard extension TYPE 10886 arguments. 10887 * Fortran 2008 support has been added: 10888 + The -std=f2008 option and support for the file extensions 10889 .f2008 and .F2008 has been added. 10890 + The g0 format descriptor is now supported. 10891 + The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH, 10892 ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED 10893 are now available (some of them existed as GNU extension 10894 before). Note: The hyperbolic functions are not yet supporting 10895 complex arguments and the three- argument version of BESSEL_*N 10896 is not available. 10897 + The bit intrinsics LEADZ and TRAILZ have been added. 10898 10899 Java (GCJ) 10900 10901 Ada 10902 10903 * The Ada runtime now supports multilibs on many platforms including 10904 x86_64, SPARC and PowerPC. Their build is enabled by default. 10905 10906 New Targets and Target Specific Improvements 10907 10908 ARM 10909 10910 * GCC now supports optimizing for the Cortex-A9, Cortex-R4 and 10911 Cortex-R4F processors and has many other improvements to 10912 optimization for ARM processors. 10913 * GCC now supports the VFPv3 variant with 16 double-precision 10914 registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been 10915 renamed to -mfpu=vfpv3. 10916 * GCC now supports the -mfix-cortex-m3-ldrd option to work around an 10917 erratum on Cortex-M3 processors. 10918 * GCC now supports the __sync_* atomic operations for ARM EABI 10919 GNU/Linux. 10920 * The section anchors optimization is now enabled by default when 10921 optimizing for ARM. 10922 * GCC now uses a new EABI-compatible profiling interface for EABI 10923 targets. This requires a function __gnu_mcount_nc, which is 10924 provided by GNU libc versions 2.8 and later. 10925 10926 AVR 10927 10928 * The -mno-tablejump option has been deprecated because it has the 10929 same effect as the -fno-jump-tables option. 10930 * Added support for these new AVR devices: 10931 + ATA6289 10932 + ATtiny13A 10933 + ATtiny87 10934 + ATtiny167 10935 + ATtiny327 10936 + ATmega8C1 10937 + ATmega16C1 10938 + ATmega32C1 10939 + ATmega8M1 10940 + ATmega16M1 10941 + ATmega32M1 10942 + ATmega32U4 10943 + ATmega16HVB 10944 + ATmega4HVD 10945 + ATmega8HVD 10946 + ATmega64C1 10947 + ATmega64M1 10948 + ATmega16U4 10949 + ATmega32U6 10950 + ATmega128RFA1 10951 + AT90PWM81 10952 + AT90SCR100 10953 + M3000F 10954 + M3000S 10955 + M3001B 10956 10957 IA-32/x86-64 10958 10959 * Support for Intel AES built-in functions and code generation is 10960 available via -maes. 10961 * Support for Intel PCLMUL built-in function and code generation is 10962 available via -mpclmul. 10963 * Support for Intel AVX built-in functions and code generation is 10964 available via -mavx. 10965 * Automatically align the stack for local variables with alignment 10966 requirement. 10967 * GCC can now utilize the SVML library for vectorizing calls to a set 10968 of C99 functions if -mveclibabi=svml is specified and you link to 10969 an SVML ABI compatible library. 10970 * On x86-64, the ABI has been changed in the following cases to 10971 conform to the x86-64 ABI: 10972 + Passing/returning structures with flexible array member: 10973 struct foo 10974 { 10975 int i; 10976 int flex[]; 10977 }; 10978 + Passing/returning structures with complex float member: 10979 struct foo 10980 { 10981 int i; 10982 __complex__ float f; 10983 }; 10984 + Passing/returning unions with long double member: 10985 union foo 10986 { 10987 int x; 10988 long double ld; 10989 }; 10990 Code built with previous versions of GCC that uses any of these is 10991 not compatible with code built with GCC 4.4.0 or later. 10992 * A new target attribute was added to allow programmers to change the 10993 target options like -msse2 or -march=k8 for an individual function. 10994 You can also change the target options via the GCC target pragma 10995 for functions defined after the pragma. 10996 * GCC can now be configured with options --with-arch-32, 10997 --with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and 10998 --with-tune-64 to control the default optimization separately for 10999 32-bit and 64-bit modes. 11000 11001 IA-32/IA64 11002 11003 * Support for __float128 (TFmode) IEEE quad type and corresponding 11004 TCmode IEEE complex quad type is available via the soft-fp library 11005 on IA-32/IA64 targets. This includes basic arithmetic operations 11006 (addition, subtraction, negation, multiplication and division) on 11007 __float128 real and TCmode complex values, the full set of IEEE 11008 comparisons between __float128 values, conversions to and from 11009 float, double and long double floating point types, as well as 11010 conversions to and from signed or unsigned integer, signed or 11011 unsigned long integer and signed or unsigned quad (TImode, IA64 11012 only) integer types. Additionally, all operations generate the full 11013 set of IEEE exceptions and support the full set of IEEE rounding 11014 modes. 11015 11016 M68K/ColdFire 11017 11018 * GCC now supports instruction scheduling for ColdFire V1, V3 and V4 11019 processors. (Scheduling support for ColdFire V2 processors was 11020 added in GCC 4.3.) 11021 * GCC now supports the -mxgot option to support programs requiring 11022 many GOT entries on ColdFire. 11023 * The m68k-*-linux-gnu target now builds multilibs by default. 11024 11025 MIPS 11026 11027 * MIPS Technologies have extended the original MIPS SVR4 ABI to 11028 include support for procedure linkage tables (PLTs) and copy 11029 relocations. These extensions allow GNU/Linux executables to use a 11030 significantly more efficient code model than the one defined by the 11031 original ABI. 11032 GCC support for this code model is available via a new command-line 11033 option, -mplt. There is also a new configure-time option, 11034 --with-mips-plt, to make -mplt the default. 11035 The new code model requires support from the assembler, the linker, 11036 and the runtime C library. This support is available in binutils 11037 2.19 and GLIBC 2.9. 11038 * GCC can now generate MIPS16 code for 32-bit GNU/Linux executables 11039 and 32-bit GNU/Linux shared libraries. This feature requires GNU 11040 binutils 2.19 or above. 11041 * Support for RMI's XLR processor is now available through the 11042 -march=xlr and -mtune=xlr options. 11043 * 64-bit targets can now perform 128-bit multiplications inline, 11044 instead of relying on a libgcc function. 11045 * Native GNU/Linux toolchains now support -march=native and 11046 -mtune=native, which select the host processor. 11047 * GCC now supports the R10K, R12K, R14K and R16K processors. The 11048 canonical -march= and -mtune= names for these processors are 11049 r10000, r12000, r14000 and r16000 respectively. 11050 * GCC can now work around the side effects of speculative execution 11051 on R10K processors. Please see the documentation of the 11052 -mr10k-cache-barrier option for details. 11053 * Support for the MIPS64 Release 2 instruction set has been added. 11054 The option -march=mips64r2 enables generation of these 11055 instructions. 11056 * GCC now supports Cavium Networks' Octeon processor. This support is 11057 available through the -march=octeon and -mtune=octeon options. 11058 * GCC now supports STMicroelectronics' Loongson 2E/2F processors. The 11059 canonical -march= and -mtune= names for these processors are 11060 loongson2e and loongson2f. 11061 11062 picochip 11063 11064 Picochip is a 16-bit processor. A typical picoChip contains over 250 11065 small cores, each with small amounts of memory. There are three 11066 processor variants (STAN, MEM and CTRL) with different instruction sets 11067 and memory configurations and they can be chosen using the -mae option. 11068 11069 This port is intended to be a "C" only port. 11070 11071 Power Architecture and PowerPC 11072 11073 * GCC now supports the e300c2, e300c3 and e500mc processors. 11074 * GCC now supports Xilinx processors with a single-precision FPU. 11075 * Decimal floating point is now supported for e500 processors. 11076 11077 S/390, zSeries and System z9/z10 11078 11079 * Support for the IBM System z10 EC/BC processor has been added. When 11080 using the -march=z10 option, the compiler will generate code making 11081 use of instructions provided by the General-Instruction-Extension 11082 Facility and the Execute-Extension Facility. 11083 11084 VxWorks 11085 11086 * GCC now supports the thread-local storage mechanism used on 11087 VxWorks. 11088 11089 Xtensa 11090 11091 * GCC now supports thread-local storage (TLS) for Xtensa processor 11092 configurations that include the Thread Pointer option. TLS also 11093 requires support from the assembler and linker; this support is 11094 provided in the GNU binutils beginning with version 2.19. 11095 11096 Documentation improvements 11097 11098 Other significant improvements 11099 11100 GCC 4.4.1 11101 11102 This is the [11]list of problem reports (PRs) from GCC's bug tracking 11103 system that are known to be fixed in the 4.4.1 release. This list might 11104 not be complete (that is, it is possible that some PRs that have been 11105 fixed are not listed here). 11106 11107 GCC 4.4.2 11108 11109 This is the [12]list of problem reports (PRs) from GCC's bug tracking 11110 system that are known to be fixed in the 4.4.2 release. This list might 11111 not be complete (that is, it is possible that some PRs that have been 11112 fixed are not listed here). 11113 11114 GCC 4.4.3 11115 11116 This is the [13]list of problem reports (PRs) from GCC's bug tracking 11117 system that are known to be fixed in the 4.4.3 release. This list might 11118 not be complete (that is, it is possible that some PRs that have been 11119 fixed are not listed here). 11120 11121 GCC 4.4.4 11122 11123 This is the [14]list of problem reports (PRs) from GCC's bug tracking 11124 system that are known to be fixed in the 4.4.4 release. This list might 11125 not be complete (that is, it is possible that some PRs that have been 11126 fixed are not listed here). 11127 11128 GCC 4.4.5 11129 11130 This is the [15]list of problem reports (PRs) from GCC's bug tracking 11131 system that are known to be fixed in the 4.4.5 release. This list might 11132 not be complete (that is, it is possible that some PRs that have been 11133 fixed are not listed here). 11134 11135 GCC 4.4.6 11136 11137 This is the [16]list of problem reports (PRs) from GCC's bug tracking 11138 system that are known to be fixed in the 4.4.6 release. This list might 11139 not be complete (that is, it is possible that some PRs that have been 11140 fixed are not listed here). 11141 11142 GCC 4.4.7 11143 11144 This is the [17]list of problem reports (PRs) from GCC's bug tracking 11145 system that are known to be fixed in the 4.4.7 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 11150 For questions related to the use of GCC, please consult these web 11151 pages and the [18]GCC manuals. If that fails, the 11152 [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11153 web pages and the development of GCC are welcome on our developer 11154 list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public 11155 archives. 11156 11157 Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and 11158 distribution of this entire article is permitted in any medium, 11159 provided this notice is preserved. 11160 11161 These pages are [23]maintained by the GCC team. Last modified 11162 2019-11-28[24]. 11163 11164 References 11165 11166 1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.7 11167 2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted 11168 3. http://gcc.gnu.org/gcc-4.4/porting_to.html 11169 4. https://gcc.gnu.org/wiki/Graphite 11170 5. http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf 11171 6. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html 11172 7. https://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html 11173 8. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125 11174 9. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221 11175 10. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34 11176 11. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1 11177 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2 11178 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3 11179 14. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4 11180 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.5 11181 16. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.6 11182 17. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.7 11183 18. https://gcc.gnu.org/onlinedocs/ 11184 19. mailto:gcc-help (a] gcc.gnu.org 11185 20. mailto:gcc (a] gcc.gnu.org 11186 21. https://gcc.gnu.org/lists.html 11187 22. https://www.fsf.org/ 11188 23. https://gcc.gnu.org/about.html 11189 24. http://validator.w3.org/check/referer 11190 ====================================================================== 11191 http://gcc.gnu.org/gcc-4.3/index.html 11192 11193 GCC 4.3 Release Series 11194 11195 (This release series is no longer supported.) 11196 11197 Jun 27, 2011 11198 11199 The [1]GNU project and the GCC developers are pleased to announce the 11200 release of GCC 4.3.6. 11201 11202 This release is a bug-fix release, containing fixes for regressions in 11203 GCC 4.3.5 relative to previous releases of GCC. 11204 11205 Release History 11206 11207 GCC 4.3.6 11208 Jun 27, 2011 ([2]changes) 11209 11210 GCC 4.3.5 11211 May 22, 2010 ([3]changes) 11212 11213 GCC 4.3.4 11214 August 4, 2009 ([4]changes) 11215 11216 GCC 4.3.3 11217 January 24, 2009 ([5]changes) 11218 11219 GCC 4.3.2 11220 August 27, 2008 ([6]changes) 11221 11222 GCC 4.3.1 11223 June 6, 2008 ([7]changes) 11224 11225 GCC 4.3.0 11226 March 5, 2008 ([8]changes) 11227 11228 References and Acknowledgements 11229 11230 GCC used to stand for the GNU C Compiler, but since the compiler 11231 supports several other languages aside from C, it now stands for the 11232 GNU Compiler Collection. 11233 11234 A list of [9]successful builds is updated as new information becomes 11235 available. 11236 11237 The GCC developers would like to thank the numerous people that have 11238 contributed new features, improvements, bug fixes, and other changes as 11239 well as test results to GCC. This [10]amazing group of volunteers is 11240 what makes GCC successful. 11241 11242 For additional information about GCC please refer to the [11]GCC 11243 project web site or contact the [12]GCC development mailing list. 11244 11245 To obtain GCC please use [13]our mirror sites or [14]our version 11246 control system. 11247 11248 11249 For questions related to the use of GCC, please consult these web 11250 pages and the [15]GCC manuals. If that fails, the 11251 [16]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 11252 web pages and the development of GCC are welcome on our developer 11253 list at [17]gcc (a] gcc.gnu.org. All of [18]our lists have public 11254 archives. 11255 11256 Copyright (C) [19]Free Software Foundation, Inc. Verbatim copying and 11257 distribution of this entire article is permitted in any medium, 11258 provided this notice is preserved. 11259 11260 These pages are [20]maintained by the GCC team. Last modified 11261 2020-01-14[21]. 11262 11263 References 11264 11265 1. http://www.gnu.org/ 11266 2. http://gcc.gnu.org/gcc-4.3/changes.html 11267 3. http://gcc.gnu.org/gcc-4.3/changes.html 11268 4. http://gcc.gnu.org/gcc-4.3/changes.html 11269 5. http://gcc.gnu.org/gcc-4.3/changes.html 11270 6. http://gcc.gnu.org/gcc-4.3/changes.html 11271 7. http://gcc.gnu.org/gcc-4.3/changes.html 11272 8. http://gcc.gnu.org/gcc-4.3/changes.html 11273 9. http://gcc.gnu.org/gcc-4.3/buildstat.html 11274 10. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 11275 11. http://gcc.gnu.org/index.html 11276 12. mailto:gcc (a] gcc.gnu.org 11277 13. http://gcc.gnu.org/mirrors.html 11278 14. http://gcc.gnu.org/git.html 11279 15. https://gcc.gnu.org/onlinedocs/ 11280 16. mailto:gcc-help (a] gcc.gnu.org 11281 17. mailto:gcc (a] gcc.gnu.org 11282 18. https://gcc.gnu.org/lists.html 11283 19. https://www.fsf.org/ 11284 20. https://gcc.gnu.org/about.html 11285 21. http://validator.w3.org/check/referer 11286 ====================================================================== 11287 http://gcc.gnu.org/gcc-4.3/changes.html 11288 11289 GCC 4.3 Release Series 11290 Changes, New Features, and Fixes 11291 11292 The latest release in the 4.3 release series is [1]GCC 4.3.5. 11293 11294 Caveats 11295 11296 * GCC requires the [2]GMP and [3]MPFR libraries for building all the 11297 various front-end languages it supports. See the [4]prerequisites 11298 page for version requirements. 11299 * ColdFire targets now treat long double as having the same format as 11300 double. In earlier versions of GCC, they used the 68881 long double 11301 format instead. 11302 * The m68k-uclinux target now uses the same calling conventions as 11303 m68k-linux-gnu. You can select the original calling conventions by 11304 configuring for m68k-uclinuxoldabi instead. Note that 11305 m68k-uclinuxoldabi also retains the original 80-bit long double on 11306 ColdFire targets. 11307 * The -fforce-mem option has been removed because it has had no 11308 effect in the last few GCC releases. 11309 * The i386 -msvr3-shlib option has been removed since it is no longer 11310 used. 11311 * Fastcall for i386 has been changed not to pass aggregate arguments 11312 in registers, following Microsoft compilers. 11313 * Support for the AOF assembler has been removed from the ARM back 11314 end; this affects only the targets arm-semi-aof and armel-semi-aof, 11315 which are no longer recognized. We removed these targets without a 11316 deprecation period because we discovered that they have been 11317 unusable since GCC 4.0.0. 11318 * Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*) 11319 has been removed. This support had been deprecated since GCC 4.0.0. 11320 * Support for a number of older systems and recently unmaintained or 11321 untested target ports of GCC has been declared obsolete in GCC 4.3. 11322 Unless there is activity to revive them, the next release of GCC 11323 will have their sources permanently removed. 11324 All GCC ports for the following processor architectures have been 11325 declared obsolete: 11326 + Morpho MT (mt-*) 11327 The following aliases for processor architectures have been 11328 declared obsolete. Users should use the indicated generic target 11329 names instead, with compile-time options such as -mcpu or 11330 configure-time options such as --with-cpu to control the 11331 configuration more precisely. 11332 + strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-* 11333 instead). 11334 + parisc*-*-* (use hppa*-*-* instead). 11335 + m680[012]0-*-* (use m68k-*-* instead). 11336 All GCC ports for the following operating systems have been 11337 declared obsolete: 11338 + BeOS (*-*-beos*) 11339 + kaOS (*-*-kaos*) 11340 + GNU/Linux using the a.out object format (*-*-linux*aout*) 11341 + GNU/Linux using version 1 of the GNU C Library 11342 (*-*-linux*libc1*) 11343 + Solaris versions before Solaris 7 (*-*-solaris2.[0-6], 11344 *-*-solaris2.[0-6].*) 11345 + Miscellaneous System V (*-*-sysv*) 11346 + WindISS (*-*-windiss*) 11347 Also, those for some individual systems on particular architectures 11348 have been obsoleted: 11349 + UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*) 11350 + CRIS with a.out object format (cris-*-aout) 11351 + BSD 4.3 on PA-RISC (hppa1.1-*-bsd*) 11352 + OSF/1 on PA-RISC (hppa1.1-*-osf*) 11353 + PRO on PA-RISC (hppa1.1-*-pro*) 11354 + Sequent PTX on IA32 (i[34567]86-sequent-ptx4*, 11355 i[34567]86-sequent-sysv4*) 11356 + SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*) 11357 + UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host 11358 was previously [5]removed in 2001, leaving only the support 11359 for UWIN as a target now being deprecated) 11360 + ChorusOS on PowerPC (powerpc-*-chorusos*) 11361 + All VAX configurations apart from NetBSD and OpenBSD 11362 (vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*) 11363 * The [6]-Wconversion option has been modified. Its purpose now is to 11364 warn for implicit conversions that may alter a value. This new 11365 behavior is available for both C and C++. Warnings about 11366 conversions between signed and unsigned integers can be disabled by 11367 using -Wno-sign-conversion. In C++, they are disabled by default 11368 unless -Wsign-conversion is explicitly requested. The old behavior 11369 of -Wconversion, that is, warn for prototypes causing a type 11370 conversion that is different from what would happen to the same 11371 argument in the absence of a prototype, has been moved to a new 11372 option -Wtraditional-conversion, which is only available for C. 11373 * The -m386, -m486, -mpentium and -mpentiumpro tuning options have 11374 been removed because they were deprecated for more than 3 GCC major 11375 releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or 11376 -mtune=pentiumpro as a replacement. 11377 * The -funsafe-math-optimizations option now automatically turns on 11378 -fno-trapping-math in addition to -fno-signed-zeros, as it enables 11379 reassociation and thus may introduce or remove traps. 11380 * The -ftree-vectorize option is now on by default under -O3. In 11381 order to generate code for a SIMD extension, it has to be enabled 11382 as well: use -maltivec for PowerPC platforms and -msse/-msse2 for 11383 i?86 and x86_64. 11384 * More information on porting to GCC 4.3 from previous versions of 11385 GCC can be found in the [7]porting guide for this release. 11386 11387 General Optimizer Improvements 11388 11389 * The GCC middle-end has been integrated with the MPFR library. This 11390 allows GCC to evaluate and replace at compile-time calls to 11391 built-in math functions having constant arguments with their 11392 mathematically equivalent results. In making use of MPFR, GCC can 11393 generate correct results regardless of the math library 11394 implementation or floating point precision of the host platform. 11395 This also allows GCC to generate identical results regardless of 11396 whether one compiles in native or cross-compile configurations to a 11397 particular target. The following built-in functions take advantage 11398 of this new capability: acos, acosh, asin, asinh, atan2, atan, 11399 atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1, 11400 fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10, 11401 log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh, 11402 tan, tanh, tgamma, y0, y1 and yn. The float and long double 11403 variants of these functions (e.g. sinf and sinl) are also handled. 11404 The sqrt and cabs functions with constant arguments were already 11405 optimized in prior GCC releases. Now they also use MPFR. 11406 * A new forward propagation pass on RTL was added. The new pass 11407 replaces several slower transformations, resulting in compile-time 11408 improvements as well as better code generation in some cases. 11409 * A new command-line switch -frecord-gcc-switches has been added to 11410 GCC, although it is only enabled for some targets. The switch 11411 causes the command line that was used to invoke the compiler to be 11412 recorded into the object file that is being created. The exact 11413 format of this recording is target and binary file format 11414 dependent, but it usually takes the form of a note section 11415 containing ASCII text. The switch is related to the -fverbose-asm 11416 switch, but that one only records the information in the assembler 11417 output file as comments, so the information never reaches the 11418 object file. 11419 * The inliner heuristic is now aware of stack frame consumption. New 11420 command-line parameters --param large-stack-frame and --param 11421 large-stack-frame-growth can be used to limit stack frame size 11422 growth caused by inlining. 11423 * During feedback directed optimizations, the expected block size the 11424 memcpy, memset and bzero functions operate on is discovered and for 11425 cases of commonly used small sizes, specialized inline code is 11426 generated. 11427 * __builtin_expect no longer requires its argument to be a compile 11428 time constant. 11429 * Interprocedural optimization was reorganized to work on functions 11430 in SSA form. This enables more precise and cheaper dataflow 11431 analysis and makes writing interprocedural optimizations easier. 11432 The following improvements have been implemented on top of this 11433 framework: 11434 + Pre-inline optimization: Selected local optimization passes 11435 are run before the inliner (and other interprocedural passes) 11436 are executed. This significantly improves the accuracy of code 11437 growth estimates used by the inliner and reduces the overall 11438 memory footprint for large compilation units. 11439 + Early inlining (a simple bottom-up inliner pass inlining only 11440 functions whose body is smaller than the expected call 11441 overhead) is now executed with the early optimization passes, 11442 thus inlining already optimized function bodies into an 11443 unoptimized function that is subsequently optimized by early 11444 optimizers. This enables the compiler to quickly eliminate 11445 abstraction penalty in C++ programs. 11446 + Interprocedural constant propagation now operate on SSA form 11447 increasing accuracy of the analysis. 11448 * A new internal representation for GIMPLE statements has been 11449 contributed, resulting in compile-time memory savings. 11450 * The vectorizer was enhanced to support vectorization of outer 11451 loops, intra-iteration parallelism (loop-aware SLP), vectorization 11452 of strided accesses and loops with multiple data-types. Run-time 11453 dependency testing using loop versioning was added. The cost model, 11454 turned on by -fvect-cost-model, was developed. 11455 11456 New Languages and Language specific improvements 11457 11458 * We have added new command-line options 11459 -finstrument-functions-exclude-function-list and 11460 -finstrument-functions-exclude-file-list. They provide more control 11461 over which functions are annotated by the -finstrument-functions 11462 option. 11463 11464 C family 11465 11466 * Implicit conversions between generic vector types are now only 11467 permitted when the two vectors in question have the same number of 11468 elements and compatible element types. (Note that the restriction 11469 involves compatible element types, not implicitly-convertible 11470 element types: thus, a vector type with element type int may not be 11471 implicitly converted to a vector type with element type unsigned 11472 int.) This restriction, which is in line with specifications for 11473 SIMD architectures such as AltiVec, may be relaxed using the flag 11474 -flax-vector-conversions. This flag is intended only as a 11475 compatibility measure and should not be used for new code. 11476 * -Warray-bounds has been added and is now enabled by default for 11477 -Wall . It produces warnings for array subscripts that can be 11478 determined at compile time to be always out of bounds. 11479 -Wno-array-bounds will disable the warning. 11480 * The constructor and destructor function attributes now accept 11481 optional priority arguments which control the order in which the 11482 constructor and destructor functions are run. 11483 * New [8]command-line options -Wtype-limits, -Wold-style-declaration, 11484 -Wmissing-parameter-type, -Wempty-body, -Wclobbered and 11485 -Wignored-qualifiers have been added for finer control of the 11486 diverse warnings enabled by -Wextra. 11487 * A new function attribute alloc_size has been added to mark up 11488 malloc style functions. For constant sized allocations this can be 11489 used to find out the size of the returned pointer using the 11490 __builtin_object_size() function for buffer overflow checking and 11491 similar. This supplements the already built-in malloc and calloc 11492 constant size handling. 11493 * Integer constants written in binary are now supported as a GCC 11494 extension. They consist of a prefix 0b or 0B, followed by a 11495 sequence of 0 and 1 digits. 11496 * A new predefined macro __COUNTER__ has been added. It expands to 11497 sequential integral values starting from 0. In conjunction with the 11498 ## operator, this provides a convenient means to generate unique 11499 identifiers. 11500 * A new command-line option -fdirectives-only has been added. It 11501 enables a special preprocessing mode which improves the performance 11502 of applications like distcc and ccache. 11503 * Fixed-point data types and operators have been added. They are 11504 based on Chapter 4 of the Embedded-C specification (n1169.pdf). 11505 Currently, only MIPS targets are supported. 11506 * Decimal floating-point arithmetic based on draft ISO/IEC TR 24732, 11507 N1241, is now supported as a GCC extension to C for targets 11508 i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu, 11509 and x86_64-*-linux-gnu. The feature introduces new data types 11510 _Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF, 11511 DD, and DL. 11512 11513 C++ 11514 11515 * [9]Experimental support for the upcoming ISO C++ standard, C++0x. 11516 * -Wc++0x-compat has been added and is now enabled by default for 11517 -Wall. It produces warnings for constructs whose meaning differs 11518 between ISO C++ 1998 and C++0x. 11519 * The -Wparentheses option now works for C++ as it does for C. It 11520 warns if parentheses are omitted when operators with confusing 11521 precedence are nested. It also warns about ambiguous else 11522 statements. Since -Wparentheses is enabled by -Wall, this may cause 11523 additional warnings with existing C++ code which uses -Wall. These 11524 new warnings may be disabled by using -Wall -Wno-parentheses. 11525 * The -Wmissing-declarations now works for C++ as it does for C. 11526 * The -fvisibility-ms-compat flag was added, to make it easier to 11527 port larger projects using shared libraries from Microsoft's Visual 11528 Studio to ELF and Mach-O systems. 11529 * C++ attribute handling has been overhauled for template arguments 11530 (ie dependent types). In particular, __attribute__((aligned(T))); 11531 works for C++ types. 11532 11533 Runtime Library (libstdc++) 11534 11535 * [10]Experimental support for the upcoming ISO C++ standard, C++0x. 11536 * Support for TR1 mathematical special functions and regular 11537 expressions. 11538 * Default what implementations give more elaborate exception strings 11539 for bad_cast, bad_typeid, bad_exception, and bad_alloc. 11540 * Header dependencies have been streamlined, reducing unnecessary 11541 includes and pre-processed bloat. 11542 * Variadic template implementations of items in <tuple> and 11543 <functional>. 11544 * An experimental [11]parallel mode has been added. This is a 11545 parallel implementation of many C++ Standard library algorithms, 11546 like std::accumulate, std::for_each, std::transform, or std::sort, 11547 to give but four examples. These algorithms can be substituted for 11548 the normal (sequential) libstdc++ algorithms on a piecemeal basis, 11549 or all existing algorithms can be transformed via the 11550 -D_GLIBCXX_PARALLEL macro. 11551 * Debug mode versions of classes in <unordered_set> and 11552 <unordered_map>. 11553 * Formal deprecation of <ext/hash_set> and <ext/hash_map>, which are 11554 now <backward/hash_set> and <backward/hash_map>. This code: 11555 #include <ext/hash_set> 11556 __gnu_cxx::hash_set<int> s; 11557 11558 Can be transformed (in order of preference) to: 11559 #include <tr1/unordered_set> 11560 std::tr1::unordered_set<int> s; 11561 11562 or 11563 #include <backward/hash_set> 11564 __gnu_cxx::hash_set<int> s; 11565 11566 Similar transformations apply to __gnu_cxx::hash_map, 11567 __gnu_cxx::hash_multimap, __gnu_cxx::hash_set, 11568 __gnu_cxx::hash_multiset. 11569 11570 Fortran 11571 11572 * Due to the fact that the GMP and MPFR libraries are required for 11573 all languages, Fortran is no longer special in this regard and is 11574 available by default. 11575 * The [12]-fexternal-blas option has been added, which generates 11576 calls to BLAS routines for intrinsic matrix operations such as 11577 matmul rather than using the built-in algorithms. 11578 * Support to give a backtrace (compiler flag -fbacktrace or 11579 environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems 11580 only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a 11581 run-time error occured. 11582 * GNU Fortran now defines __GFORTRAN__ when it runs the C 11583 preprocessor (CPP). 11584 * The [13]-finit-local-zero, -finit-real, -finit-integer, 11585 -finit-character, and -finit-logical options have been added, which 11586 can be used to initialize local variables. 11587 * The intrinsic procedures [14]GAMMA and [15]LGAMMA have been added, 11588 which calculate the Gamma function and its logarithm. Use EXTERNAL 11589 gamma if you want to use your own gamma function. 11590 * GNU Fortran now regards the backslash character as literal (as 11591 required by the Fortran 2003 standard); using [16]-fbackslash GNU 11592 Fortran interprets backslashes as C-style escape characters. 11593 * The [17]interpretation of binary, octal and hexadecimal (BOZ) 11594 literal constants has been changed. Before they were always 11595 interpreted as integer; now they are bit-wise transferred as 11596 argument of INT, REAL, DBLE and CMPLX as required by the Fortran 11597 2003 standard, and for real and complex variables in DATA 11598 statements or when directly assigned to real and complex variables. 11599 Everywhere else and especially in expressions they are still 11600 regarded as integer constants. 11601 * Fortran 2003 support has been extended: 11602 + Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE 11603 + Pointer intent 11604 + Intrinsic module ISO_ENV_FORTRAN 11605 + Interoperability with C (ISO C Bindings) 11606 + ABSTRACT INTERFACES and PROCEDURE statements (without POINTER 11607 attribute) 11608 + Fortran 2003 BOZ 11609 11610 Java (GCJ) 11611 11612 * GCJ now uses the Eclipse Java compiler for its Java parsing needs. 11613 This enables the use of all 1.5 language features, and fixes most 11614 existing front end bugs. 11615 * libgcj now supports all 1.5 language features which require runtime 11616 support: foreach, enum, annotations, generics, and auto-boxing. 11617 * We've made many changes to the tools shipped with gcj. 11618 + The old jv-scan tool has been removed. This tool never really 11619 worked properly. There is no replacement. 11620 + gcjh has been rewritten. Some of its more obscure options no 11621 longer work, but are still recognized in an attempt at 11622 compatibility. gjavah is a new program with similar 11623 functionality but different command-line options. 11624 + grmic and grmiregistry have been rewritten. grmid has been 11625 added. 11626 + gjar replaces the old fastjar. 11627 + gjarsigner (used for signing jars), gkeytool (used for key 11628 management), gorbd (for CORBA), gserialver (computes 11629 serialization UIDs), and gtnameserv (also for CORBA) are now 11630 installed. 11631 * The ability to dump the contents of the java run time heap to a 11632 file for off-line analysis has been added. The heap dumps may be 11633 analyzed with the new gc-analyze tool. They may be generated on 11634 out-of-memory conditions or on demand and are controlled by the new 11635 run time class gnu.gcj.util.GCInfo. 11636 * java.util.TimeZone can now read files from /usr/share/zoneinfo to 11637 provide correct, updated, timezone information. This means that 11638 packagers no longer have to update libgcj when a time zone change 11639 is published. 11640 11641 New Targets and Target Specific Improvements 11642 11643 IA-32/x86-64 11644 11645 * Tuning for Intel Core 2 processors is available via -mtune=core2 11646 and -march=core2. 11647 * Tuning for AMD Geode processors is available via -mtune=geode and 11648 -march=geode. 11649 * Code generation of block move (memcpy) and block set (memset) was 11650 rewritten. GCC can now pick the best algorithm (loop, unrolled 11651 loop, instruction with rep prefix or a library call) based on the 11652 size of the block being copied and the CPU being optimized for. A 11653 new option -minline-stringops-dynamically has been added. With this 11654 option string operations of unknown size are expanded such that 11655 small blocks are copied by in-line code, while for large blocks a 11656 library call is used. This results in faster code than 11657 -minline-all-stringops when the library implementation is capable 11658 of using cache hierarchy hints. The heuristic choosing the 11659 particular algorithm can be overwritten via -mstringop-strategy. 11660 Newly also memset of values different from 0 is inlined. 11661 * GCC no longer places the cld instruction before string operations. 11662 Both i386 and x86-64 ABI documents mandate the direction flag to be 11663 clear at the entry of a function. It is now invalid to set the flag 11664 in asm statement without reseting it afterward. 11665 * Support for SSSE3 built-in functions and code generation are 11666 available via -mssse3. 11667 * Support for SSE4.1 built-in functions and code generation are 11668 available via -msse4.1. 11669 * Support for SSE4.2 built-in functions and code generation are 11670 available via -msse4.2. 11671 * Both SSE4.1 and SSE4.2 support can be enabled via -msse4. 11672 * A new set of options -mpc32, -mpc64 and -mpc80 have been added to 11673 allow explicit control of x87 floating point precision. 11674 * Support for __float128 (TFmode) IEEE quad type and corresponding 11675 TCmode IEEE complex quad type is available via the soft-fp library 11676 on x86_64 targets. This includes basic arithmetic operations 11677 (addition, subtraction, negation, multiplication and division) on 11678 __float128 real and TCmode complex values, the full set of IEEE 11679 comparisons between __float128 values, conversions to and from 11680 float, double and long double floating point types, as well as 11681 conversions to and from signed or unsigned integer, signed or 11682 unsigned long integer and signed or unsigned quad (TImode) integer 11683 types. Additionally, all operations generate the full set of IEEE 11684 exceptions and support the full set of IEEE rounding modes. 11685 * GCC can now utilize the ACML library for vectorizing calls to a set 11686 of C99 functions on x86_64 if -mveclibabi=acml is specified and you 11687 link to an ACML ABI compatible library. 11688 11689 ARM 11690 11691 * Compiler and Library support for Thumb-2 and the ARMv7 architecture 11692 has been added. 11693 11694 CRIS 11695 11696 New features 11697 11698 * Compiler and Library support for the CRIS v32 architecture, as 11699 found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been 11700 added. 11701 11702 Configuration changes 11703 11704 * The cris-*-elf target now includes support for CRIS v32, including 11705 libraries, through the -march=v32 option. 11706 * A new crisv32-*-elf target defaults to generate code for CRIS v32. 11707 * A new crisv32-*-linux* target defaults to generate code for CRIS 11708 v32. 11709 * The cris-*-aout target has been obsoleted. 11710 11711 Improved support for built-in functions 11712 11713 * GCC can now use the lz and swapwbr instructions to implement the 11714 __builtin_clz, __builtin_ctz and __builtin_ffs family of functions. 11715 * __builtin_bswap32 is now implemented using the swapwb instruction, 11716 when available. 11717 11718 m68k and ColdFire 11719 11720 New features 11721 11722 * Support for several new ColdFire processors has been added. You can 11723 generate code for them using the new -mcpu option. 11724 * All targets now support ColdFire processors. 11725 * m68k-uclinux targets have improved support for C++ constructors and 11726 destructors, and for shared libraries. 11727 * It is now possible to set breakpoints on the first or last line of 11728 a function, even if there are no statements on that line. 11729 11730 Optimizations 11731 11732 * Support for sibling calls has been added. 11733 * More use is now made of the ColdFire mov3q instruction. 11734 * __builtin_clz is now implemented using the ff1 ColdFire 11735 instruction, when available. 11736 * GCC now honors the -m68010 option. 68010 code now uses clr rather 11737 than move to zero volatile memory. 11738 * 68020 targets and above can now use symbol(index.size*scale) 11739 addresses for indexed array accesses. Earlier compilers would 11740 always load the symbol into a base register first. 11741 11742 Configuration changes 11743 11744 * All m68k and ColdFire targets now allow the default processor to be 11745 set at configure time using --with-cpu. 11746 * A --with-arch configuration option has been added. This option 11747 allows you to restrict a target to ColdFire or non-ColdFire 11748 processors. 11749 11750 Preprocessor macros 11751 11752 * An __mcfv*__ macro is now defined for all ColdFire targets. 11753 (Earlier versions of GCC only defined __mcfv4e__.) 11754 * __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added. 11755 * All targets now define __mc68010 and __mc68010__ when generating 11756 68010 code. 11757 11758 Command-line changes 11759 11760 * New command-line options -march, -mcpu, -mtune and -mhard-float 11761 have been added. These options apply to both m68k and ColdFire 11762 targets. 11763 * -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative 11764 versions of -mshort, etc. 11765 * -fforce-addr has been removed. It is now ignored by the compiler. 11766 11767 Other improvements 11768 11769 * ColdFire targets now try to maintain a 4-byte-aligned stack where 11770 possible. 11771 * m68k-uclinux targets now try to avoid situations that lead to the 11772 load-time error: BINFMT_FLAT: reloc outside program. 11773 11774 MIPS 11775 11776 Changes to existing configurations 11777 11778 * libffi and libjava now support all three GNU/Linux ABIs: o32, n32 11779 and n64. Every GNU/Linux configuration now builds these libraries 11780 by default. 11781 * GNU/Linux configurations now generate -mno-shared code unless 11782 overridden by -fpic, -fPIC, -fpie or -fPIE. 11783 * mipsisa32*-linux-gnu configurations now generate hard-float code by 11784 default, just like other mipsisa32* and mips*-linux-gnu 11785 configurations. You can build a soft-float version of any 11786 mips*-linux-gnu configuration by passing --with-float=soft to 11787 configure. 11788 * mips-wrs-vxworks now supports run-time processes (RTPs). 11789 11790 Changes to existing command-line options 11791 11792 * The -march and -mtune options no longer accept 24k as a processor 11793 name. Please use 24kc, 24kf2_1 or 24kf1_1 instead. 11794 * The -march and -mtune options now accept 24kf2_1, 24kef2_1 and 11795 34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The 11796 options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for 11797 24kx, 24kex and 34kx. 11798 11799 New configurations 11800 11801 GCC now supports the following configurations: 11802 * mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by 11803 default. Earlier releases also recognized this configuration, but 11804 they treated it in the same way as mipsisa32*-linux-gnu*. Note that 11805 you can customize any mips*-linux-gnu* configuration to a 11806 particular ISA or processor by passing an appropriate --with-arch 11807 option to configure. 11808 * mipsisa*-sde-elf*, which provides compatibility with MIPS 11809 Technologies' SDE toolchains. The configuration uses the SDE 11810 libraries by default, but you can use it like other newlib-based 11811 ELF configurations by passing --with-newlib to configure. It is the 11812 only configuration besides mips64vr*-elf* to build MIPS16 as well 11813 as non-MIPS16 libraries. 11814 * mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf* 11815 configuration, but uses the o32 and o64 ABIs instead of the 32-bit 11816 and 64-bit forms of the EABI. 11817 11818 New processors and application-specific extensions 11819 11820 * Support for the SmartMIPS ASE is available through the new 11821 -msmartmips option. 11822 * Support for revision 2 of the DSP ASE is available through the new 11823 -mdspr2 option. A new preprocessor macro called __mips_dsp_rev 11824 indicates the revision of the ASE in use. 11825 * Support for the 4KS and 74K families of processors is available 11826 through the -march and -mtune options. 11827 11828 Improved support for built-in functions 11829 11830 * GCC can now use load-linked, store-conditional and sync 11831 instructions to implement atomic built-in functions such as 11832 __sync_fetch_and_add. The memory reference must be 4 bytes wide for 11833 32-bit targets and either 4 or 8 bytes wide for 64-bit targets. 11834 * GCC can now use the clz and dclz instructions to implement the 11835 __builtin_ctz and __builtin_ffs families of functions. 11836 * There is a new __builtin___clear_cache function for flushing the 11837 instruction cache. GCC expands this function inline on MIPS32 11838 revision 2 targets, otherwise it calls the function specified by 11839 -mcache-flush-func. 11840 11841 MIPS16 improvements 11842 11843 * GCC can now compile objects that contain a mixture of MIPS16 and 11844 non-MIPS16 code. There are two new attributes, mips16 and nomips16, 11845 for specifying which mode a function should use. 11846 * A new option called -minterlink-mips16 makes non-MIPS16 code 11847 link-compatible with MIPS16 code. 11848 * After many bug fixes, the long-standing MIPS16 -mhard-float support 11849 should now work fairly reliably. 11850 * GCC can now use the MIPS16e save and restore instructions. 11851 * -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled 11852 with -G0 -fsection-anchors is often smaller than code compiled with 11853 -G8. However, please note that you must usually compile all objects 11854 in your application with the same -G option; see the documentation 11855 of -G for details. 11856 * A new option called-mcode-readable specifies which instructions are 11857 allowed to load from the code segment. -mcode-readable=yes is the 11858 default and says that any instruction may load from the code 11859 segment. The other alternatives are -mcode-readable=pcrel, which 11860 says that only PC-relative MIPS16 instructions may load from the 11861 code segment, and -mcode-readable=no, which says that no 11862 instruction may do so. Please see the documentation for more 11863 details, including example uses. 11864 11865 Small-data improvements 11866 11867 There are three new options for controlling small data: 11868 * -mno-extern-sdata, which disables small-data accesses for 11869 externally-defined variables. Code compiled with -Gn 11870 -mno-extern-sdata will be link-compatible with any -G setting 11871 between -G0 and -Gn inclusive. 11872 * -mno-local-sdata, which disables the use of small-data sections for 11873 data that is not externally visible. This option can be a useful 11874 way of reducing small-data usage in less performance-critical parts 11875 of an application. 11876 * -mno-gpopt, which disables the use of the $gp register while still 11877 honoring the -G limit when placing externally-visible data. This 11878 option implies -mno-extern-sdata and -mno-local-sdata and it can be 11879 useful in situations where $gp does not necessarily hold the 11880 expected value. 11881 11882 Miscellaneous improvements 11883 11884 * There is a new option called -mbranch-cost for tweaking the 11885 perceived cost of branches. 11886 * If GCC is configured to use a version of GAS that supports the 11887 .gnu_attribute directive, it will use that directive to record 11888 certain properties of the output code. .gnu_attribute is new to GAS 11889 2.18. 11890 * There are two new function attributes, near and far, for overriding 11891 the command-line setting of -mlong-calls on a function-by-function 11892 basis. 11893 * -mfp64, which previously required a 64-bit target, now works with 11894 MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and 11895 mipsisa*-sde-elf* configurations provide suitable library support. 11896 * GCC now recognizes the -mdmx and -mmt options and passes them down 11897 to the assembler. It does nothing else with the options at present. 11898 11899 SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture 11900 (BEA) 11901 11902 * Support has been added for this new architecture. 11903 11904 RS6000 (POWER/PowerPC) 11905 11906 * Support for the PowerPC 750CL paired-single instructions has been 11907 added with a new powerpc-*-linux*paired* target configuration. It 11908 is enabled by an associated -mpaired option and can be accessed 11909 using new built-in functions. 11910 * Support for auto-detecting architecture and system configuration to 11911 auto-select processor optimization tuning. 11912 * Support for VMX on AIX 5.3 has been added. 11913 * Support for AIX Version 6.1 has been added. 11914 11915 S/390, zSeries and System z9 11916 11917 * Support for the IBM System z9 EC/BC processor (z9 GA3) has been 11918 added. When using the -march=z9-ec option, the compiler will 11919 generate code making use of instructions provided by the decimal 11920 floating point facility and the floating point conversion facility 11921 (pfpo). Besides the instructions used to implement decimal floating 11922 point operations these facilities also contain instructions to move 11923 between general purpose and floating point registers and to modify 11924 and copy the sign-bit of floating point values. 11925 * When the -march=z9-ec option is used the new 11926 -mhard-dfp/-mno-hard-dfp options can be used to specify whether the 11927 decimal floating point hardware instructions will be used or not. 11928 If none of them is given the hardware support is enabled by 11929 default. 11930 * The -mstack-guard option can now be omitted when using stack 11931 checking via -mstack-size in order to let GCC choose a sensible 11932 stack guard value according to the frame size of each function. 11933 * Various changes to improve performance of generated code have been 11934 implemented, including: 11935 + The condition code set by an add logical with carry 11936 instruction is now available for overflow checks like: a + b + 11937 carry < b. 11938 + The test data class instruction is now used to implement 11939 sign-bit and infinity checks of binary and decimal floating 11940 point numbers. 11941 11942 SPARC 11943 11944 * Support for the Sun UltraSPARC T2 (Niagara 2) processor has been 11945 added. 11946 11947 Xtensa 11948 11949 * Stack unwinding for exception handling now uses by default a 11950 specialized version of DWARF unwinding. This is not 11951 binary-compatible with the setjmp/longjmp (sjlj) unwinding used for 11952 Xtensa with previous versions of GCC. 11953 * For Xtensa processors that include the Conditional Store option, 11954 the built-in functions for atomic memory access are now implemented 11955 using S32C1I instructions. 11956 * If the Xtensa NSA option is available, GCC will use it to implement 11957 the __builtin_ctz and __builtin_clz functions. 11958 11959 Documentation improvements 11960 11961 * Existing libstdc++ documentation has been edited and restructured 11962 into a single DocBook XML manual. The results can be viewed online 11963 [18]here. 11964 11965 Other significant improvements 11966 11967 * The compiler's --help command-line option has been extended so that 11968 it now takes an optional set of arguments. These arguments restrict 11969 the information displayed to specific classes of command-line 11970 options, and possibly only a subset of those options. It is also 11971 now possible to replace the descriptive text associated with each 11972 displayed option with an indication of its current value, or for 11973 binary options, whether it has been enabled or disabled. 11974 Here are some examples. The following will display all the options 11975 controlling warning messages: 11976 --help=warnings 11977 11978 Whereas this will display all the undocumented, target specific 11979 options: 11980 --help=target,undocumented 11981 11982 This sequence of commands will display the binary optimizations 11983 that are enabled by -O3: 11984 gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts 11985 gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts 11986 diff /tmp/O2-opts /tmp/O3-opts | grep enabled 11987 11988 * The configure options --with-pkgversion and --with-bugurl have been 11989 added. These allow distributors of GCC to include a 11990 distributor-specific string in manuals and --version output and to 11991 specify the URL for reporting bugs in their versions of GCC. 11992 11993 GCC 4.3.1 11994 11995 This is the [19]list of problem reports (PRs) from GCC's bug tracking 11996 system that are known to be fixed in the 4.3.1 release. This list might 11997 not be complete (that is, it is possible that some PRs that have been 11998 fixed are not listed here). 11999 12000 Target Specific Changes 12001 12002 IA-32/x86-64 12003 12004 ABI changes 12005 12006 * Starting with GCC 4.3.1, decimal floating point variables are 12007 aligned to their natural boundaries when they are passed on the 12008 stack for i386. 12009 12010 Command-line changes 12011 12012 * Starting with GCC 4.3.1, the -mcld option has been added to 12013 automatically generate a cld instruction in the prologue of 12014 functions that use string instructions. This option is used for 12015 backward compatibility on some operating systems and can be enabled 12016 by default for 32-bit x86 targets by configuring GCC with the 12017 --enable-cld configure option. 12018 12019 GCC 4.3.2 12020 12021 This is the [20]list of problem reports (PRs) from GCC's bug tracking 12022 system that are known to be fixed in the 4.3.2 release. This list might 12023 not be complete (that is, it is possible that some PRs that have been 12024 fixed are not listed here). 12025 12026 GCC 4.3.3 12027 12028 This is the [21]list of problem reports (PRs) from GCC's bug tracking 12029 system that are known to be fixed in the 4.3.3 release. This list might 12030 not be complete (that is, it is possible that some PRs that have been 12031 fixed are not listed here). 12032 12033 GCC 4.3.4 12034 12035 This is the [22]list of problem reports (PRs) from GCC's bug tracking 12036 system that are known to be fixed in the 4.3.4 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 GCC 4.3.5 12041 12042 This is the [23]list of problem reports (PRs) from GCC's bug tracking 12043 system that are known to be fixed in the 4.3.5 release. This list might 12044 not be complete (that is, it is possible that some PRs that have been 12045 fixed are not listed here). 12046 12047 GCC 4.3.6 12048 12049 This is the [24]list of problem reports (PRs) from GCC's bug tracking 12050 system that are known to be fixed in the 4.3.6 release. This list might 12051 not be complete (that is, it is possible that some PRs that have been 12052 fixed are not listed here). 12053 12054 12055 For questions related to the use of GCC, please consult these web 12056 pages and the [25]GCC manuals. If that fails, the 12057 [26]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12058 web pages and the development of GCC are welcome on our developer 12059 list at [27]gcc (a] gcc.gnu.org. All of [28]our lists have public 12060 archives. 12061 12062 Copyright (C) [29]Free Software Foundation, Inc. Verbatim copying and 12063 distribution of this entire article is permitted in any medium, 12064 provided this notice is preserved. 12065 12066 These pages are [30]maintained by the GCC team. Last modified 12067 2019-11-28[31]. 12068 12069 References 12070 12071 1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.5 12072 2. https://gmplib.org/ 12073 3. https://www.mpfr.org/ 12074 4. https://gcc.gnu.org/install/prerequisites.html 12075 5. https://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html 12076 6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options 12077 7. http://gcc.gnu.org/gcc-4.3/porting_to.html 12078 8. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 12079 9. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 12080 10. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html 12081 11. https://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html 12082 12. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options 12083 13. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167 12084 14. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html 12085 15. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html 12086 16. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html 12087 17. https://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html 12088 18. https://gcc.gnu.org/onlinedocs/libstdc++/ 12089 19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1 12090 20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2 12091 21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3 12092 22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4 12093 23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.5 12094 24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.6 12095 25. https://gcc.gnu.org/onlinedocs/ 12096 26. mailto:gcc-help (a] gcc.gnu.org 12097 27. mailto:gcc (a] gcc.gnu.org 12098 28. https://gcc.gnu.org/lists.html 12099 29. https://www.fsf.org/ 12100 30. https://gcc.gnu.org/about.html 12101 31. http://validator.w3.org/check/referer 12102 ====================================================================== 12103 http://gcc.gnu.org/gcc-4.2/index.html 12104 12105 GCC 4.2 Release Series 12106 12107 (This release series is no longer supported.) 12108 12109 May 19, 2008 12110 12111 The [1]GNU project and the GCC developers are pleased to announce the 12112 release of GCC 4.2.4. 12113 12114 This release is a bug-fix release, containing fixes for regressions in 12115 GCC 4.2.3 relative to previous releases of GCC. 12116 12117 Release History 12118 12119 GCC 4.2.4 12120 May 19, 2008 ([2]changes) 12121 12122 GCC 4.2.3 12123 February 1, 2008 ([3]changes) 12124 12125 GCC 4.2.2 12126 October 7, 2007 ([4]changes) 12127 12128 GCC 4.2.1 12129 July 18, 2007 ([5]changes) 12130 12131 GCC 4.2.0 12132 May 13, 2007 ([6]changes) 12133 12134 References and Acknowledgements 12135 12136 GCC used to stand for the GNU C Compiler, but since the compiler 12137 supports several other languages aside from C, it now stands for the 12138 GNU Compiler Collection. 12139 12140 A list of [7]successful builds is updated as new information becomes 12141 available. 12142 12143 The GCC developers would like to thank the numerous people that have 12144 contributed new features, improvements, bug fixes, and other changes as 12145 well as test results to GCC. This [8]amazing group of volunteers is 12146 what makes GCC successful. 12147 12148 For additional information about GCC please refer to the [9]GCC project 12149 web site or contact the [10]GCC development mailing list. 12150 12151 To obtain GCC please use [11]our mirror sites or [12]our version 12152 control system. 12153 12154 12155 For questions related to the use of GCC, please consult these web 12156 pages and the [13]GCC manuals. If that fails, the 12157 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12158 web pages and the development of GCC are welcome on our developer 12159 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 12160 archives. 12161 12162 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 12163 distribution of this entire article is permitted in any medium, 12164 provided this notice is preserved. 12165 12166 These pages are [18]maintained by the GCC team. Last modified 12167 2020-01-14[19]. 12168 12169 References 12170 12171 1. http://www.gnu.org/ 12172 2. http://gcc.gnu.org/gcc-4.2/changes.html 12173 3. http://gcc.gnu.org/gcc-4.2/changes.html 12174 4. http://gcc.gnu.org/gcc-4.2/changes.html 12175 5. http://gcc.gnu.org/gcc-4.2/changes.html 12176 6. http://gcc.gnu.org/gcc-4.2/changes.html 12177 7. http://gcc.gnu.org/gcc-4.2/buildstat.html 12178 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 12179 9. http://gcc.gnu.org/index.html 12180 10. mailto:gcc (a] gcc.gnu.org 12181 11. http://gcc.gnu.org/mirrors.html 12182 12. http://gcc.gnu.org/git.html 12183 13. https://gcc.gnu.org/onlinedocs/ 12184 14. mailto:gcc-help (a] gcc.gnu.org 12185 15. mailto:gcc (a] gcc.gnu.org 12186 16. https://gcc.gnu.org/lists.html 12187 17. https://www.fsf.org/ 12188 18. https://gcc.gnu.org/about.html 12189 19. http://validator.w3.org/check/referer 12190 ====================================================================== 12191 http://gcc.gnu.org/gcc-4.2/changes.html 12192 12193 GCC 4.2 Release Series 12194 Changes, New Features, and Fixes 12195 12196 Caveats 12197 12198 * GCC no longer accepts the -fshared-data option. This option has had 12199 no effect in any GCC 4 release; the targets to which the option 12200 used to apply had been removed before GCC 4.0. 12201 12202 General Optimizer Improvements 12203 12204 * New command-line options specify the possible relationships among 12205 parameters and between parameters and global data. For example, 12206 -fargument-noalias-anything specifies that arguments do not alias 12207 any other storage. 12208 Each language will automatically use whatever option is required by 12209 the language standard. You should not need to use these options 12210 yourself. 12211 12212 New Languages and Language specific improvements 12213 12214 * [1]OpenMP is now supported for the C, C++ and Fortran compilers. 12215 * New command-line options -fstrict-overflow and -Wstrict-overflow 12216 have been added. -fstrict-overflow tells the compiler that it may 12217 assume that the program follows the strict signed overflow 12218 semantics permitted for the language: for C and C++ this means that 12219 the compiler may assume that signed overflow does not occur. For 12220 example, a loop like 12221 for (i = 1; i > 0; i *= 2) 12222 12223 is presumably intended to continue looping until i overflows. With 12224 -fstrict-overflow, the compiler may assume that signed overflow 12225 will not occur, and transform this into an infinite loop. 12226 -fstrict-overflow is turned on by default at -O2, and may be 12227 disabled via -fno-strict-overflow. The -Wstrict-overflow option may 12228 be used to warn about cases where the compiler assumes that signed 12229 overflow will not occur. It takes five different levels: 12230 -Wstrict-overflow=1 to 5. See the [2]documentation for details. 12231 -Wstrict-overflow=1 is enabled by -Wall. 12232 * The new command-line option -fno-toplevel-reorder directs GCC to 12233 emit top-level functions, variables, and asm statements in the same 12234 order that they appear in the input file. This is intended to 12235 support existing code which relies on a particular ordering (for 12236 example, code which uses top-level asm statements to switch 12237 sections). For new code, it is generally better to use function and 12238 variable attributes. The -fno-toplevel-reorder option may be used 12239 for most cases which currently use -fno-unit-at-a-time. The 12240 -fno-unit-at-a-time option will be removed in some future version 12241 of GCC. If you know of a case which requires -fno-unit-at-a-time 12242 which is not fixed by -fno-toplevel-reorder, please open a bug 12243 report. 12244 12245 C family 12246 12247 * The pragma redefine_extname will now macro expand its tokens for 12248 compatibility with SunPRO. 12249 * In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct 12250 GCC to handle inline functions as specified in the C99 standard. In 12251 preparation for this, GCC 4.2 will warn about any use of non-static 12252 inline functions in gnu99 or c99 mode. This new warning may be 12253 disabled with the new gnu_inline function attribute or the new 12254 -fgnu89-inline command-line option. Also, GCC 4.2 and later will 12255 define one of the preprocessor macros __GNUC_GNU_INLINE__ or 12256 __GNUC_STDC_INLINE__ to indicate the semantics of inline functions 12257 in the current compilation. 12258 * A new command-line option -Waddress has been added to warn about 12259 suspicious uses of memory addresses as, for example, using the 12260 address of a function in a conditional expression, and comparisons 12261 against the memory address of a string literal. This warning is 12262 enabled by -Wall. 12263 12264 C++ 12265 12266 * C++ visibility handling has been overhauled. 12267 Restricted visiblity is propagated from classes to members, from 12268 functions to local statics, and from templates and template 12269 arguments to instantiations, unless the latter has explicitly 12270 declared visibility. 12271 The visibility attribute for a class must come between the 12272 class-key and the name, not after the closing brace. 12273 Attributes are now allowed for enums and elaborated-type-specifiers 12274 that only declare a type. 12275 Members of the anonymous namespace are now local to a particular 12276 translation unit, along with any other declarations which use them, 12277 though they are still treated as having external linkage for 12278 language semantics. 12279 * The (undocumented) extension which permitted templates with default 12280 arguments to be bound to template template parameters with fewer 12281 parameters has been removed. For example: 12282 template <template <typename> class C> 12283 void f(C<double>) {} 12284 12285 template <typename T, typename U = int> 12286 struct S {}; 12287 12288 template void f(S<double>); 12289 12290 is no longer accepted by G++. The reason this code is not accepted 12291 is that S is a template with two parameters; therefore, it cannot 12292 be bound to C which has only one parameter. 12293 * The <?, >?, <?=, and >?= operators, deprecated in previous GCC 12294 releases, have been removed. 12295 * The command-line option -fconst-strings, deprecated in previous GCC 12296 releases, has been removed. 12297 * The configure variable enable-__cxa_atexit is now enabled by 12298 default for more targets. Enabling this variable is necessary in 12299 order for static destructors to be executed in the correct order, 12300 but it depends upon the presence of a non-standard C library in the 12301 target library in order to work. The variable is now enabled for 12302 more targets which are known to have suitable C libraries. 12303 * -Wextra will produce warnings for if statements with a semicolon as 12304 the only body, to catch code like: 12305 if (a); 12306 return 1; 12307 return 0; 12308 12309 To suppress the warning in valid cases, use { } instead. 12310 * The C++ front end now also produces strict aliasing warnings when 12311 -fstrict-aliasing -Wstrict-aliasing is in effect. 12312 12313 Runtime Library (libstdc++) 12314 12315 * Added support for TR1 <random>, <complex>, and C compatibility 12316 headers. In addition, a lock-free version of shared_ptr was 12317 contributed as part of Phillip Jordan's Google Summer of Code 12318 project on lock-free containers. 12319 * In association with the Summer of Code work on lock-free 12320 containers, the interface for atomic builtins was adjusted, 12321 creating simpler alternatives for non-threaded code paths. Also, 12322 usage was consolidated and all elements were moved from namespace 12323 std to namespace__gnu_cxx. Affected interfaces are the functions 12324 __exchange_and_add, __atomic_add, and the objects __mutex, 12325 __recursive_mutex, and __scoped_lock. 12326 * Support for versioning weak symbol names via namespace association 12327 was added. However, as this changes the names of exported symbols, 12328 this is turned off by default in the current ABI. Intrepid users 12329 can enable this feature by using 12330 --enable-symvers=gnu-versioned-namespace during configuration. 12331 * Revised, simplified, and expanded policy-based associative 12332 containers, including data types for tree and trie forms 12333 (basic_tree, tree, trie), lists (list_update), and both 12334 collision-chaining and probing hash-based containers 12335 (basic_hash_table, cc_hash_table, gp_hash_table). More details per 12336 the [3]documentation. 12337 * The implementation of the debug mode was modified, whereby the 12338 debug namespaces were nested inside of namespace std and namespace 12339 __gnu_cxx in order to resolve some long standing corner cases 12340 involving name lookup. Debug functionality from the policy-based 12341 data structures was consolidated and enabled with the single macro, 12342 _GLIBCXX_DEBUG. See PR 26142 for more information. 12343 * Added extensions for type traits: __conditional_type, 12344 __numeric_traits, __add_unsigned, __removed_unsigned, __enable_if. 12345 * Added a typelist implementation for compile-time meta-programming. 12346 Elements for typelist construction and operation can be found 12347 within namespace __gnu_cxx::typelist. 12348 * Added a new allocator, __gnu_cxx::throw_allocator, for testing 12349 exception-safety. 12350 * Enabled library-wide visibility control, allowing -fvisibility to 12351 be used. 12352 * Consolidated all nested namespaces and the conversion of 12353 __gnu_internal implementation-private details to anonymous 12354 namespaces whenever possible. 12355 * Implemented LWG resolutions DR 431 and DR 538. 12356 12357 Fortran 12358 12359 * Support for allocatable components has been added (TR 15581 and 12360 Fortran 2003). 12361 * Support for the Fortran 2003 streaming IO extension has been added. 12362 * The GNU Fortran compiler now uses 4-byte record markers by default 12363 for unformatted files to be compatible with g77 and most other 12364 compilers. The implementation allows for records greater than 2 GB 12365 and is compatible with several other compilers. Older versions of 12366 gfortran used 8-byte record markers by default (on most systems). 12367 In order to change the length of the record markers, e.g. to read 12368 unformatted files created by older gfortran versions, the 12369 [4]-frecord-marker=8 option can be used. 12370 12371 Java (GCJ) 12372 12373 * A new command-line option -static-libgcj has been added for targets 12374 that use a linker compatible with GNU Binutils. As its name 12375 implies, this causes libgcj to be linked statically. In some cases 12376 this causes the resulting executable to start faster and use less 12377 memory than if the shared version of libgcj were used. However 12378 caution should be used as it can also cause essential parts of the 12379 library to be omitted. Some of these issues are discussed in: 12380 [5]https://gcc.gnu.org/wiki/Statically_linking_libgcj 12381 * fastjar is no longer bundled with GCC. To build libgcj, you will 12382 need either InfoZIP (both zip and unzip) or an external jar 12383 program. In the former case, the GCC build will install a jar shell 12384 script that is based on InfoZIP and provides the same functionality 12385 as fastjar. 12386 12387 New Targets and Target Specific Improvements 12388 12389 IA-32/x86-64 12390 12391 * -mtune=generic can now be used to generate code running well on 12392 common x86 chips. This includes AMD Athlon, AMD Opteron, Intel 12393 Pentium-M, Intel Pentium 4 and Intel Core 2. 12394 * -mtune=native and -march=native will produce code optimized for the 12395 host architecture as detected using the cpuid instruction. 12396 * Added a new command-line option -fstackrealign and and 12397 __attribute__ ((force_align_arg_pointer)) to realign the stack at 12398 runtime. This allows functions compiled with a vector-aligned stack 12399 to be invoked from legacy objects that keep only word-alignment. 12400 12401 SPARC 12402 12403 * The default CPU setting has been changed from V7 to V9 in 32-bit 12404 mode on Solaris 7 and above. This is already the case in 64-bit 12405 mode. It can be overridden by specifying --with-cpu at configure 12406 time. 12407 * Back-end support of built-in functions for atomic memory access has 12408 been implemented. 12409 * Support for the Sun UltraSPARC T1 (Niagara) processor has been 12410 added. 12411 12412 M32C 12413 12414 * Various bug fixes have made some functions (notably, functions 12415 returning structures) incompatible with previous releases. 12416 Recompiling all libraries is recommended. Note that code quality 12417 has considerably improved since 4.1, making a recompile even more 12418 beneficial. 12419 12420 MIPS 12421 12422 * Added support for the Broadcom SB-1A core. 12423 12424 IA-64 12425 12426 * Added support for IA-64 data and control speculation. By default 12427 speculation is enabled only during second scheduler pass. A number 12428 of machine flags was introduced to control the usage of speculation 12429 for both scheduler passes. 12430 12431 HPPA 12432 12433 * Added Java language support (libffi and libjava) for 32-bit HP-UX 12434 11 target. 12435 12436 Obsolete Systems 12437 12438 Documentation improvements 12439 12440 PDF Documentation 12441 12442 * A make pdf target has been added to the top-level makefile, 12443 enabling automated production of PDF documentation files. 12444 (Front-ends external to GCC should modify their Make-lang.in file 12445 to add a lang.pdf: target.) 12446 12447 Other significant improvements 12448 12449 Build system improvements 12450 12451 * All the components of the compiler are now bootstrapped by default. 12452 This improves the resilience to bugs in the system compiler or 12453 binary compatibility problems, as well as providing better testing 12454 of GCC 4.2 itself. In addition, if you build the compiler from a 12455 combined tree, the assembler, linker, etc. will also be 12456 bootstrapped (i.e. built with themselves). 12457 You can disable this behavior, and go back to the pre-GCC 4.2 set 12458 up, by configuring GCC with --disable-bootstrap. 12459 * The rules that configure follows to find target tools resemble more 12460 closely the locations that the built compiler will search. In 12461 addition, you can use the new configure option --with-target-tools 12462 to specify where to find the target tools used during the build, 12463 without affecting what the built compiler will use. 12464 This can be especially useful when building packages of GCC. For 12465 example, you may want to build GCC with GNU as or ld, even if the 12466 resulting compiler to work with the native assembler and linker. To 12467 do so, you can use --with-target-tools to point to the native 12468 tools. 12469 12470 Incompatible changes to the build system 12471 12472 * Front-ends external to GCC should modify their Make-lang.in file to 12473 replace double-colon rules (e.g. dvi::) with normal rules (like 12474 lang.dvi:). Front-end makefile hooks do not use double-colon rules 12475 anymore. 12476 * Up to GCC 4.1, a popular way to specify the target tools used 12477 during the build was to create directories named gas, binutils, 12478 etc. in the build tree, and create links to the tools from there. 12479 This does not work any more when the compiler is bootstrapped. The 12480 new configure option --with-target-tools provides a better way to 12481 achieve the same effect, and works for all native and cross 12482 settings. 12483 12484 12485 For questions related to the use of GCC, please consult these web 12486 pages and the [6]GCC manuals. If that fails, the 12487 [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12488 web pages and the development of GCC are welcome on our developer 12489 list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives. 12490 12491 Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and 12492 distribution of this entire article is permitted in any medium, 12493 provided this notice is preserved. 12494 12495 These pages are [11]maintained by the GCC team. Last modified 12496 2019-11-28[12]. 12497 12498 References 12499 12500 1. http://gcc.gnu.org/projects/gomp/ 12501 2. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html 12502 3. https://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html 12503 4. https://gcc.gnu.org/onlinedocs/gfortran/Runtime-Options.html 12504 5. https://gcc.gnu.org/wiki/Statically_linking_libgcj 12505 6. https://gcc.gnu.org/onlinedocs/ 12506 7. mailto:gcc-help (a] gcc.gnu.org 12507 8. mailto:gcc (a] gcc.gnu.org 12508 9. https://gcc.gnu.org/lists.html 12509 10. https://www.fsf.org/ 12510 11. https://gcc.gnu.org/about.html 12511 12. http://validator.w3.org/check/referer 12512 ====================================================================== 12513 http://gcc.gnu.org/gcc-4.1/index.html 12514 12515 GCC 4.1 Release Series 12516 12517 (This release series is no longer supported.) 12518 12519 February 13, 2007 12520 12521 The [1]GNU project and the GCC developers are pleased to announce the 12522 release of GCC 4.1.2. 12523 12524 This release is a bug-fix release, containing fixes for regressions in 12525 GCC 4.1.1 relative to previous releases of GCC. 12526 12527 Release History 12528 12529 GCC 4.1.2 12530 February 13, 2007 ([2]changes) 12531 12532 GCC 4.1.1 12533 May 24, 2006 ([3]changes) 12534 12535 GCC 4.1.0 12536 February 28, 2006 ([4]changes) 12537 12538 References and Acknowledgements 12539 12540 GCC used to stand for the GNU C Compiler, but since the compiler 12541 supports several other languages aside from C, it now stands for the 12542 GNU Compiler Collection. 12543 12544 A list of [5]successful builds is updated as new information becomes 12545 available. 12546 12547 The GCC developers would like to thank the numerous people that have 12548 contributed new features, improvements, bug fixes, and other changes as 12549 well as test results to GCC. This [6]amazing group of volunteers is 12550 what makes GCC successful. 12551 12552 For additional information about GCC please refer to the [7]GCC project 12553 web site or contact the [8]GCC development mailing list. 12554 12555 To obtain GCC please use [9]our mirror sites or [10]our version control 12556 system. 12557 12558 12559 For questions related to the use of GCC, please consult these web 12560 pages and the [11]GCC manuals. If that fails, the 12561 [12]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 12562 web pages and the development of GCC are welcome on our developer 12563 list at [13]gcc (a] gcc.gnu.org. All of [14]our lists have public 12564 archives. 12565 12566 Copyright (C) [15]Free Software Foundation, Inc. Verbatim copying and 12567 distribution of this entire article is permitted in any medium, 12568 provided this notice is preserved. 12569 12570 These pages are [16]maintained by the GCC team. Last modified 12571 2020-01-14[17]. 12572 12573 References 12574 12575 1. http://www.gnu.org/ 12576 2. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 12577 3. http://gcc.gnu.org/gcc-4.1/changes.html 12578 4. http://gcc.gnu.org/gcc-4.1/changes.html 12579 5. http://gcc.gnu.org/gcc-4.1/buildstat.html 12580 6. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 12581 7. http://gcc.gnu.org/index.html 12582 8. mailto:gcc (a] gcc.gnu.org 12583 9. http://gcc.gnu.org/mirrors.html 12584 10. http://gcc.gnu.org/git.html 12585 11. https://gcc.gnu.org/onlinedocs/ 12586 12. mailto:gcc-help (a] gcc.gnu.org 12587 13. mailto:gcc (a] gcc.gnu.org 12588 14. https://gcc.gnu.org/lists.html 12589 15. https://www.fsf.org/ 12590 16. https://gcc.gnu.org/about.html 12591 17. http://validator.w3.org/check/referer 12592 ====================================================================== 12593 http://gcc.gnu.org/gcc-4.1/changes.html 12594 12595 GCC 4.1 Release Series 12596 Changes, New Features, and Fixes 12597 12598 The latest release in the 4.1 release series is [1]GCC 4.1.2. 12599 12600 Caveats 12601 12602 General Optimizer Improvements 12603 12604 * GCC now has infrastructure for inter-procedural optimizations and 12605 the following inter-procedural optimizations are implemented: 12606 + Profile guided inlining. When doing profile feedback guided 12607 optimization, GCC can now use the profile to make better 12608 informed decisions on whether inlining of a function is 12609 profitable or not. This means that GCC will no longer inline 12610 functions at call sites that are not executed very often, and 12611 that functions at hot call sites are more likely to be 12612 inlined. 12613 A new parameter min-inline-recursive-probability is also now 12614 available to throttle recursive inlining of functions with 12615 small average recursive depths. 12616 + Discovery of pure and const functions, a form of side-effects 12617 analysis. While older GCC releases could also discover such 12618 special functions, the new IPA-based pass runs earlier so that 12619 the results are available to more optimizers. The pass is also 12620 simply more powerful than the old one. 12621 + Analysis of references to static variables and type escape 12622 analysis, also forms of side-effects analysis. The results of 12623 these passes allow the compiler to be less conservative about 12624 call-clobbered variables and references. This results in more 12625 redundant loads being eliminated and in making static 12626 variables candidates for register promotion. 12627 + Improvement of RTL-based alias analysis. The results of type 12628 escape analysis are fed to the RTL type-based alias analyzer, 12629 allowing it to disambiguate more memory references. 12630 + Interprocedural constant propagation and function versioning. 12631 This pass looks for functions that are always called with the 12632 same constant value for one or more of the function arguments, 12633 and propagates those constants into those functions. 12634 + GCC will now eliminate static variables whose usage was 12635 optimized out. 12636 + -fwhole-program --combine can now be used to make all 12637 functions in program static allowing whole program 12638 optimization. As an exception, the main function and all 12639 functions marked with the new externally_visible attribute are 12640 kept global so that programs can link with runtime libraries. 12641 * GCC can now do a form of partial dead code elimination (PDCE) that 12642 allows code motion of expressions to the paths where the result of 12643 the expression is actually needed. This is not always a win, so the 12644 pass has been limited to only consider profitable cases. Here is an 12645 example: 12646 int foo (int *, int *); 12647 int 12648 bar (int d) 12649 { 12650 int a, b, c; 12651 b = d + 1; 12652 c = d + 2; 12653 a = b + c; 12654 if (d) 12655 { 12656 foo (&b, &c); 12657 a = b + c; 12658 } 12659 printf ("%d\n", a); 12660 } 12661 12662 The a = b + c can be sunk to right before the printf. Normal code 12663 sinking will not do this, it will sink the first one above into the 12664 else-branch of the conditional jump, which still gives you two 12665 copies of the code. 12666 * GCC now has a value range propagation pass. This allows the 12667 compiler to eliminate bounds checks and branches. The results of 12668 the pass can also be used to accurately compute branch 12669 probabilities. 12670 * The pass to convert PHI nodes to straight-line code (a form of 12671 if-conversion for GIMPLE) has been improved significantly. The two 12672 most significant improvements are an improved algorithm to 12673 determine the order in which the PHI nodes are considered, and an 12674 improvement that allow the pass to consider if-conversions of basic 12675 blocks with more than two predecessors. 12676 * Alias analysis improvements. GCC can now differentiate between 12677 different fields of structures in Tree-SSA's virtual operands form. 12678 This lets stores/loads from non-overlapping structure fields not 12679 conflict. A new algorithm to compute points-to sets was contributed 12680 that can allows GCC to see now that p->a and p->b, where p is a 12681 pointer to a structure, can never point to the same field. 12682 * Various enhancements to auto-vectorization: 12683 + Incrementally preserve SSA form when vectorizing. 12684 + Incrementally preserve loop-closed form when vectorizing. 12685 + Improvements to peeling for alignment: generate better code 12686 when the misalignment of an access is known at compile time, 12687 or when different accesses are known to have the same 12688 misalignment, even if the misalignment amount itself is 12689 unknown. 12690 + Consider dependence distance in the vectorizer. 12691 + Externalize generic parts of data reference analysis to make 12692 this analysis available to other passes. 12693 + Vectorization of conditional code. 12694 + Reduction support. 12695 * GCC can now partition functions in sections of hot and cold code. 12696 This can significantly improve performance due to better 12697 instruction cache locality. This feature works best together with 12698 profile feedback driven optimization. 12699 * A new pass to avoid saving of unneeded arguments to the stack in 12700 vararg functions if the compiler can prove that they will not be 12701 needed. 12702 * Transition of basic block profiling to tree level implementation 12703 has been completed. The new implementation should be considerably 12704 more reliable (hopefully avoiding profile mismatch errors when 12705 using -fprofile-use or -fbranch-probabilities) and can be used to 12706 drive higher level optimizations, such as inlining. 12707 The -ftree-based-profiling command-line option was removed and 12708 -fprofile-use now implies disabling old RTL level loop optimizer 12709 (-fno-loop-optimize). Speculative prefetching optimization 12710 (originally enabled by -fspeculative-prefetching) was removed. 12711 12712 New Languages and Language specific improvements 12713 12714 C and Objective-C 12715 12716 * The old Bison-based C and Objective-C parser has been replaced by a 12717 new, faster hand-written recursive-descent parser. 12718 12719 Ada 12720 12721 * The build infrastructure for the Ada runtime library and tools has 12722 been changed to be better integrated with the rest of the build 12723 infrastructure of GCC. This should make doing cross builds of Ada a 12724 bit easier. 12725 12726 C++ 12727 12728 * ARM-style name-injection of friend declarations is no longer the 12729 default. For example: 12730 struct S { 12731 friend void f(); 12732 }; 12733 12734 void g() { f(); } 12735 will not be accepted; instead a declaration of f will need to be 12736 present outside of the scope of S. The new -ffriend-injection 12737 option will enable the old behavior. 12738 * The (undocumented) extension which permitted templates with default 12739 arguments to be bound to template template parameters with fewer 12740 parameters has been deprecated, and will be removed in the next 12741 major release of G++. For example: 12742 template <template <typename> class C> 12743 void f(C<double>) {} 12744 12745 template <typename T, typename U = int> 12746 struct S {}; 12747 12748 template void f(S<double>); 12749 12750 makes use of the deprecated extension. The reason this code is not 12751 valid ISO C++ is that S is a template with two parameters; 12752 therefore, it cannot be bound to C which has only one parameter. 12753 12754 Runtime Library (libstdc++) 12755 12756 * Optimization work: 12757 + A new implementation of std::search_n is provided, better 12758 performing in case of random access iterators. 12759 + Added further efficient specializations of istream functions, 12760 i.e., character array and string extractors. 12761 + Other smaller improvements throughout. 12762 * Policy-based associative containers, designed for high-performance, 12763 flexibility and semantic safety are delivered in ext/pb_assoc. 12764 * A versatile string class, __gnu_cxx::__versa_string, providing 12765 facilities conforming to the standard requirements for 12766 basic_string, is delivered in <ext/vstring.h>. In particular: 12767 + Two base classes are provided: the default one avoids 12768 reference counting and is optimized for short strings; the 12769 alternate one, still uses it while improving in a few low 12770 level areas (e.g., alignment). See vstring_fwd.h for some 12771 useful typedefs. 12772 + Various algorithms have been rewritten (e.g., replace), the 12773 code streamlined and simple optimizations added. 12774 + Option 3 of DR 431 is implemented for both available bases, 12775 thus improving the support for stateful allocators. 12776 * As usual, many bugs have been fixed (e.g., libstdc++/13583, 12777 libstdc++/23953) and LWG resolutions put into effect for the first 12778 time (e.g., DR 280, DR 464, N1780 recommendations for DR 233, TR1 12779 Issue 6.19). The implementation status of TR1 is now tracked in the 12780 docs in tr1.html. 12781 12782 Objective-C++ 12783 12784 * A new language front end for Objective-C++ has been added. This 12785 language allows users to mix the object oriented features of 12786 Objective-C with those of C++. 12787 12788 Java (GCJ) 12789 12790 * Core library (libgcj) updates based on GNU Classpath 0.15 - 0.19 12791 features (plus some 0.20 bug-fixes) 12792 + Networking 12793 o The java.net.HttpURLConnection implementation no longer 12794 buffers the entire response body in memory. This means 12795 that response bodies larger than available memory can now 12796 be handled. 12797 + (N)IO 12798 o NIO FileChannel.map implementation, fast bulk put 12799 implementation for DirectByteBuffer (speeds up this 12800 method 10x). 12801 o FileChannel.lock() and FileChannel.force() implemented. 12802 + XML 12803 o gnu.xml fix for nodes created outside a namespace 12804 context. 12805 o Add support for output indenting and 12806 cdata-section-elements output instruction in 12807 xml.transform. 12808 o xml.xpath corrections for cases where elements/attributes 12809 might have been created in non-namespace-aware mode. 12810 Corrections to handling of XSL variables and minor 12811 conformance updates. 12812 + AWT 12813 o GNU JAWT implementation, the AWT Native Interface, which 12814 allows direct access to native screen resources from 12815 within a Canvas's paint method. GNU Classpath Examples 12816 comes with a Demo, see libjava/classpath/examples/README. 12817 o awt.datatransfer updated to 1.5 with support for 12818 FlavorEvents. The gtk+ awt peers now allow copy/paste of 12819 text, images, URIs/files and serialized objects with 12820 other applications and tracking clipboard change events 12821 with gtk+ 2.6 (for gtk+ 2.4 only text and serialized 12822 objects are supported). A GNU Classpath Examples 12823 datatransfer Demo was added to show the new 12824 functionality. 12825 o Split gtk+ awt peers event handling in two threads and 12826 improve gdk lock handling (solves several awt lock ups). 12827 o Speed up awt Image loading. 12828 o Better gtk+ scrollbar peer implementation when using gtk+ 12829 >= 2.6. 12830 o Handle image loading errors correctly for gdkpixbuf and 12831 MediaTracker. 12832 o Better handle GDK lock. Properly prefix gtkpeer native 12833 functions (cp_gtk). 12834 o GdkGraphics2D has been updated to use Cairo 0.5.x or 12835 higher. 12836 o BufferedImage and GtkImage rewrites. All image drawing 12837 operations should now work correctly (flipping requires 12838 gtk+ >= 2.6) 12839 o Future Graphics2D, image and text work is documented at: 12840 [2]http://developer.classpath.org/mediation/ClasspathGrap 12841 hicsImagesText 12842 o When gtk+ 2.6 or higher is installed the default log 12843 handler will produce stack traces whenever a WARNING, 12844 CRITICAL or ERROR message is produced. 12845 + Free Swing 12846 o The RepaintManager has been reworked for more efficient 12847 painting, especially for large GUIs. 12848 o The layout manager OverlayLayout has been implemented, 12849 the BoxLayout has been rewritten to make use of the 12850 SizeRequirements utility class and caching for more 12851 efficient layout. 12852 o Improved accessibility support. 12853 o Significant progress has been made in the implementation 12854 of the javax.swing.plaf.metal package, with most UI 12855 delegates in a working state now. Please test this with 12856 your own applications and provide feedback that will help 12857 us to improve this package. 12858 o The GUI demo (gnu.classpath.examples.swing.Demo) has been 12859 extended to highlight various features in our Free Swing 12860 implementation. And it includes a look and feel switcher 12861 for Metal (default), Ocean and GNU themes. 12862 o The javax.swing.plaf.multi package is now implemented. 12863 o Editing and several key actions for JTree and JTable were 12864 implemented. 12865 o Lots of icons and look and feel improvements for Free 12866 Swing basic and metal themes were added. Try running the 12867 GNU Classpath Swing Demo in examples 12868 (gnu.classpath.examples.swing.Demo) with: 12869 -Dswing.defaultlaf=javax.swing.plaf.basic.BasicLookAndFee 12870 l or 12871 -Dswing.defaultlaf=javax.swing.plaf.metal.MetalLookAndFee 12872 l 12873 o Start of styled text capabilites for java.swing.text. 12874 o DefaultMutableTreeNode pre-order, post-order, depth-first 12875 and breadth-first traversal enumerations implemented. 12876 o JInternalFrame colors and titlebar draw properly. 12877 o JTree is working up to par (icons, selection and keyboard 12878 traversal). 12879 o JMenus were made more compatible in visual and 12880 programmatic behavior. 12881 o JTable changeSelection and multiple selections 12882 implemented. 12883 o JButton and JToggleButton change states work properly 12884 now. 12885 o JFileChooser fixes. 12886 o revalidate() and repaint() fixes which make Free Swing 12887 much more responsive. 12888 o MetalIconFactory implemented. 12889 o Free Swing Top-Level Compatibility. JFrame, JDialog, 12890 JApplet, JInternalFrame, and JWindow are now 1.5 12891 compatible in the sense that you can call add() and 12892 setLayout() directly on them, which will have the same 12893 effect as calling getContentPane().add() and 12894 getContentPane().setLayout(). 12895 o The JTree interface has been completed. JTrees now 12896 recognizes mouse clicks and selections work. 12897 o BoxLayout works properly now. 12898 o Fixed GrayFilter to actually work. 12899 o Metal SplitPane implemented. 12900 o Lots of Free Swing text and editor stuff work now. 12901 + Free RMI and Corba 12902 o Andrew Watson, Vice President and Technical Director of 12903 the Object Management Group, has officially assigned us 12904 20 bit Vendor Minor Code Id: 0x47430 ("GC") that will 12905 mark remote classpath-specific system exceptions. 12906 Obtaining the VMCID means that GNU Classpath now is a 12907 recogniseable type of node in a highly interoperable 12908 CORBA world. 12909 o GNU Classpath now includes the first working draft to 12910 support the RMI over IIOP protocol. The current 12911 implementation is capable of remote invocations, 12912 transferring various Serializables and Externalizables 12913 via RMI-IIOP protocol. It can flatten graphs and, at 12914 least for the simple cases, is interoperable with 1.5 12915 JDKs. 12916 o org.omg.PortableInterceptor and related functionality in 12917 other packages is now implemented: 12918 # The sever and client interceptors work as required 12919 since 1.4. 12920 # The IOR interceptor works as needed for 1.5. 12921 o The org.omg.DynamicAny package is completed and passes 12922 the prepared tests. 12923 o The Portable Object Adapter should now support the output 12924 of the recent IDL to java compilers. These compilers now 12925 generate servants and not CORBA objects as before, making 12926 the output depend on the existing POA implementation. 12927 Completing POA means that such code can already be tried 12928 to run on Classpath. Our POA is tested for the following 12929 usager scenarios: 12930 # POA converts servant to the CORBA object. 12931 # Servant provides to the CORBA object. 12932 # POA activates new CORBA object with the given Object 12933 Id (byte array) that is later accessible for the 12934 servant. 12935 # During the first call, the ServantActivator provides 12936 servant for this and all subsequent calls on the 12937 current object. 12938 # During each call, the ServantLocator provides 12939 servant for this call only. 12940 # ServantLocator or ServantActivator forwards call to 12941 another server. 12942 # POA has a single servant, responsible for all 12943 objects. 12944 # POA has a default servant, but some objects are 12945 explicitly connected to they specific servants. 12946 The POA is verified using tests from the former 12947 cost.omg.org. 12948 o The CORBA implementation is now a working prototype that 12949 should support features up to 1.3 inclusive. We invite 12950 groups writing CORBA dependent applications to try 12951 Classpath implementation, reporting any possible bugs. 12952 The CORBA prototype is interoperable with Sun's 12953 implementation v 1.4, transferring object references, 12954 primitive types, narrow and wide strings, arrays, 12955 structures, trees, abstract interfaces and value types 12956 (feature of CORBA 2.3) between these two platforms. 12957 Remote exceptions are transferred and handled correctly. 12958 The stringified object references (IORs) from various 12959 sources are parsed as required. The transient (for 12960 current session) and permanent (till jre restart) 12961 redirections work. Both Little and Big Endian encoded 12962 messages are accepted. The implementation is verified 12963 using tests from the former cost.omg.org. The current 12964 release includes working examples (see the examples 12965 directory), demonstrating the client-server 12966 communication, using either CORBA Request or IDL-based 12967 stub (usually generated by a IDL to java compiler). These 12968 examples also show how to use the Classpath CORBA naming 12969 service. The IDL to java compiler is not yet written, but 12970 as our library must be compatible, it naturally accepts 12971 the output of other idlj implementations. 12972 + Misc 12973 o Updated TimeZone data against Olson tzdata2005l. 12974 o Make zip and jar packages UTF-8 clean. 12975 o "native" code builds and compiles (warning free) on 12976 Darwin and Solaris. 12977 o java.util.logging.FileHandler now rotates files. 12978 o Start of a generic JDWP framework in gnu/classpath/jdwp. 12979 This is unfinished, but feedback (at classpath (a] gnu.org) 12980 from runtime hackers is greatly appreciated. Although 12981 most of the work is currently being done around gcj/gij 12982 we want this framework to be as VM neutral as possible. 12983 Early design is described in: 12984 [3]https://gcc.gnu.org/ml/java/2005-05/msg00260.html 12985 o QT4 AWT peers, enable by giving configure 12986 --enable-qt-peer. Included, but not ready for production 12987 yet. They are explicitly disabled and not supported. But 12988 if you want to help with the development of these new 12989 features we are interested in feedback. You will have to 12990 explicitly enable them to try them out (and they will 12991 most likely contain bugs). 12992 o Documentation fixes all over the place. See 12993 [4]http://developer.classpath.org/doc/ 12994 12995 New Targets and Target Specific Improvements 12996 12997 IA-32/x86-64 12998 12999 * The x86-64 medium model (that allows building applications whose 13000 data segment exceeds 4GB) was redesigned to match latest ABI draft. 13001 New implementation split large datastructures into separate segment 13002 improving performance of accesses to small datastructures and also 13003 allows linking of small model libraries into medium model programs 13004 as long as the libraries are not accessing the large datastructures 13005 directly. Medium model is also supported in position independent 13006 code now. 13007 The ABI change results in partial incompatibility among medium 13008 model objects. Linking medium model libraries (or objects) compiled 13009 with new compiler into medium model program compiled with older 13010 will likely result in exceeding ranges of relocations. 13011 Binutils 2.16.91 or newer are required for compiling medium model 13012 now. 13013 13014 RS6000 (POWER/PowerPC) 13015 13016 * The AltiVec vector primitives in <altivec.h> are now implemented in 13017 a way that puts a smaller burden on the preprocessor, instead 13018 processing the "overloading" in the front ends. This should benefit 13019 compilation speed on AltiVec vector code. 13020 * AltiVec initializers now are generated more efficiently. 13021 * The popcountb instruction available on POWER5 now is generated. 13022 * The floating point round to integer instructions available on 13023 POWER5+ now is generated. 13024 * Floating point divides can be synthesized using the floating point 13025 reciprocal estimate instructions. 13026 * Double precision floating point constants are initialized as single 13027 precision values if they can be represented exactly. 13028 13029 S/390, zSeries and System z9 13030 13031 * Support for the IBM System z9 109 processor has been added. When 13032 using the -march=z9-109 option, the compiler will generate code 13033 making use of instructions provided by the extended immediate 13034 facility. 13035 * Support for 128-bit IEEE floating point has been added. When using 13036 the -mlong-double-128 option, the compiler will map the long double 13037 data type to 128-bit IEEE floating point. Using this option 13038 constitutes an ABI change, and requires glibc support. 13039 * Various changes to improve performance of generated code have been 13040 implemented, including: 13041 + In functions that do not require a literal pool, register %r13 13042 (which is traditionally reserved as literal pool pointer), can 13043 now be freely used for other purposes by the compiler. 13044 + More precise tracking of register use allows the compiler to 13045 generate more efficient function prolog and epilog code in 13046 certain cases. 13047 + The SEARCH STRING, COMPARE LOGICAL STRING, and MOVE STRING 13048 instructions are now used to implement C string functions. 13049 + The MOVE CHARACTER instruction with single byte overlap is now 13050 used to implement the memset function with non-zero fill byte. 13051 + The LOAD ZERO instructions are now used where appropriate. 13052 + The INSERT CHARACTERS UNDER MASK, STORE CHARACTERS UNDER MASK, 13053 and INSERT IMMEDIATE instructions are now used more frequently 13054 to optimize bitfield operations. 13055 + The BRANCH ON COUNT instruction is now used more frequently. 13056 In particular, the fact that a loop contains a subroutine call 13057 no longer prevents the compiler from using this instruction. 13058 + The compiler is now aware that all shift and rotate 13059 instructions implicitly truncate the shift count to six bits. 13060 * Back-end support for the following generic features has been 13061 implemented: 13062 + The full set of [5]built-in functions for atomic memory 13063 access. 13064 + The -fstack-protector feature. 13065 + The optimization pass avoiding unnecessary stores of incoming 13066 argument registers in functions with variable argument list. 13067 13068 SPARC 13069 13070 * The default code model in 64-bit mode has been changed from 13071 Medium/Anywhere to Medium/Middle on Solaris. 13072 * TLS support is disabled by default on Solaris prior to release 10. 13073 It can be enabled on TLS-capable Solaris 9 versions (4/04 release 13074 and later) by specifying --enable-tls at configure time. 13075 13076 MorphoSys 13077 13078 * Support has been added for this new architecture. 13079 13080 Obsolete Systems 13081 13082 Documentation improvements 13083 13084 Other significant improvements 13085 13086 * GCC can now emit code for protecting applications from 13087 stack-smashing attacks. The protection is realized by buffer 13088 overflow detection and reordering of stack variables to avoid 13089 pointer corruption. 13090 * Some built-in functions have been fortified to protect them against 13091 various buffer overflow (and format string) vulnerabilities. 13092 Compared to the mudflap bounds checking feature, the safe builtins 13093 have far smaller overhead. This means that programs built using 13094 safe builtins should not experience any measurable slowdown. 13095 13096 GCC 4.1.2 13097 13098 This is the [6]list of problem reports (PRs) from GCC's bug tracking 13099 system that are known to be fixed in the 4.1.2 release. This list might 13100 not be complete (that is, it is possible that some PRs that have been 13101 fixed are not listed here). 13102 13103 When generating code for a shared library, GCC now recognizes that 13104 global functions may be replaced when the program runs. Therefore, it 13105 is now more conservative in deducing information from the bodies of 13106 functions. For example, in this example: 13107 void f() {} 13108 void g() { 13109 try { f(); } 13110 catch (...) { 13111 cout << "Exception"; 13112 } 13113 } 13114 13115 G++ would previously have optimized away the catch clause, since it 13116 would have concluded that f cannot throw exceptions. Because users may 13117 replace f with another function in the main body of the program, this 13118 optimization is unsafe, and is no longer performed. If you wish G++ to 13119 continue to optimize as before, you must add a throw() clause to the 13120 declaration of f to make clear that it does not throw exceptions. 13121 13122 13123 For questions related to the use of GCC, please consult these web 13124 pages and the [7]GCC manuals. If that fails, the 13125 [8]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13126 web pages and the development of GCC are welcome on our developer 13127 list at [9]gcc (a] gcc.gnu.org. All of [10]our lists have public 13128 archives. 13129 13130 Copyright (C) [11]Free Software Foundation, Inc. Verbatim copying and 13131 distribution of this entire article is permitted in any medium, 13132 provided this notice is preserved. 13133 13134 These pages are [12]maintained by the GCC team. Last modified 13135 2019-11-28[13]. 13136 13137 References 13138 13139 1. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2 13140 2. http://developer.classpath.org/mediation/ClasspathGraphicsImagesText 13141 3. https://gcc.gnu.org/ml/java/2005-05/msg00260.html 13142 4. http://developer.classpath.org/doc/ 13143 5. https://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html 13144 6. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.1.2 13145 7. https://gcc.gnu.org/onlinedocs/ 13146 8. mailto:gcc-help (a] gcc.gnu.org 13147 9. mailto:gcc (a] gcc.gnu.org 13148 10. https://gcc.gnu.org/lists.html 13149 11. https://www.fsf.org/ 13150 12. https://gcc.gnu.org/about.html 13151 13. http://validator.w3.org/check/referer 13152 ====================================================================== 13153 http://gcc.gnu.org/gcc-4.0/index.html 13154 13155 GCC 4.0 Release Series 13156 13157 (This release series is no longer supported.) 13158 13159 January 31, 2007 13160 13161 The [1]GNU project and the GCC developers are pleased to announce the 13162 release of GCC 4.0.4. 13163 13164 This release is a bug-fix release, containing fixes for regressions in 13165 GCC 4.0.3 relative to previous releases of GCC. 13166 13167 Release History 13168 13169 GCC 4.0.4 13170 January 31, 2007 ([2]changes) 13171 13172 GCC 4.0.3 13173 March 10, 2006 ([3]changes) 13174 13175 GCC 4.0.2 13176 September 28, 2005 ([4]changes) 13177 13178 GCC 4.0.1 13179 July 7, 2005 ([5]changes) 13180 13181 GCC 4.0.0 13182 April 20, 2005 ([6]changes) 13183 13184 References and Acknowledgements 13185 13186 GCC used to stand for the GNU C Compiler, but since the compiler 13187 supports several other languages aside from C, it now stands for the 13188 GNU Compiler Collection. 13189 13190 A list of [7]successful builds is updated as new information becomes 13191 available. 13192 13193 The GCC developers would like to thank the numerous people that have 13194 contributed new features, improvements, bug fixes, and other changes as 13195 well as test results to GCC. This [8]amazing group of volunteers is 13196 what makes GCC successful. 13197 13198 For additional information about GCC please refer to the [9]GCC project 13199 web site or contact the [10]GCC development mailing list. 13200 13201 To obtain GCC please use [11]our mirror sites, or [12]our version 13202 control system. 13203 13204 13205 For questions related to the use of GCC, please consult these web 13206 pages and the [13]GCC manuals. If that fails, the 13207 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13208 web pages and the development of GCC are welcome on our developer 13209 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 13210 archives. 13211 13212 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 13213 distribution of this entire article is permitted in any medium, 13214 provided this notice is preserved. 13215 13216 These pages are [18]maintained by the GCC team. Last modified 13217 2020-01-14[19]. 13218 13219 References 13220 13221 1. http://www.gnu.org/ 13222 2. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 13223 3. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.3 13224 4. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.2 13225 5. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.1 13226 6. http://gcc.gnu.org/gcc-4.0/changes.html 13227 7. http://gcc.gnu.org/gcc-4.0/buildstat.html 13228 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13229 9. http://gcc.gnu.org/index.html 13230 10. mailto:gcc (a] gcc.gnu.org 13231 11. http://gcc.gnu.org/mirrors.html 13232 12. http://gcc.gnu.org/git.html 13233 13. https://gcc.gnu.org/onlinedocs/ 13234 14. mailto:gcc-help (a] gcc.gnu.org 13235 15. mailto:gcc (a] gcc.gnu.org 13236 16. https://gcc.gnu.org/lists.html 13237 17. https://www.fsf.org/ 13238 18. https://gcc.gnu.org/about.html 13239 19. http://validator.w3.org/check/referer 13240 ====================================================================== 13241 http://gcc.gnu.org/gcc-4.0/changes.html 13242 13243 GCC 4.0 Release Series 13244 Changes, New Features, and Fixes 13245 13246 The latest release in the 4.0 release series is [1]GCC 4.0.4. 13247 13248 Caveats 13249 13250 * GCC now generates location lists by default when compiling with 13251 debug info and optimization. 13252 + GDB 6.0 and older crashes when it sees location lists. GDB 6.1 13253 or later is needed to debug binaries containing location 13254 lists. 13255 + When you are trying to view a value of a variable in a part of 13256 a function where it has no location (for example when the 13257 variable is no longer used and thus its location was used for 13258 something else) GDB will say that it is not available. 13259 You can disable generating location lists by -fno-var-tracking. 13260 * GCC no longer accepts the -fwritable-strings option. Use named 13261 character arrays when you need a writable string. 13262 * The options -freduce-all-givs and -fmove-all-movables have been 13263 discontinued. They were used to circumvent a shortcoming in the 13264 heuristics of the old loop optimization code with respect to common 13265 Fortran constructs. The new (tree) loop optimizer works differently 13266 and doesn't need those work-arounds. 13267 * The graph-coloring register allocator, formerly enabled by the 13268 option -fnew-ra, has been discontinued. 13269 * -I- has been deprecated. -iquote is meant to replace the need for 13270 this option. 13271 * The MIPS -membedded-pic and -mrnames options have been removed. 13272 * All MIPS targets now require the GNU assembler. In particular, IRIX 13273 configurations can no longer use the MIPSpro assemblers, although 13274 they do still support the MIPSpro linkers. 13275 * The SPARC option -mflat has been removed. 13276 * English-language diagnostic messages will now use Unicode quotation 13277 marks in UTF-8 locales. (Non-English messages already used the 13278 quotes appropriate for the language in previous releases.) If your 13279 terminal does not support UTF-8 but you are using a UTF-8 locale 13280 (such locales are the default on many GNU/Linux systems) then you 13281 should set LC_CTYPE=C in the environment to disable that locale. 13282 Programs that parse diagnostics and expect plain ASCII 13283 English-language messages should set LC_ALL=C. See [2]Markus Kuhn's 13284 explanation of Unicode quotation marks for more information. 13285 * The specs file is no longer installed on most platforms. Most users 13286 will be totally unaffected. However, if you are accustomed to 13287 editing the specs file yourself, you will now have to use the 13288 -dumpspecs option to generate the specs file, and then edit the 13289 resulting file. 13290 13291 General Optimizer Improvements 13292 13293 * The [3]tree ssa branch has been merged. This merge has brought in a 13294 completely new optimization framework based on a higher level 13295 intermediate representation than the existing RTL representation. 13296 Numerous new code transformations based on the new framework are 13297 available in GCC 4.0, including: 13298 + Scalar replacement of aggregates 13299 + Constant propagation 13300 + Value range propagation 13301 + Partial redundancy elimination 13302 + Load and store motion 13303 + Strength reduction 13304 + Dead store elimination 13305 + Dead and unreachable code elimination 13306 + [4]Autovectorization 13307 + Loop interchange 13308 + Tail recursion by accumulation 13309 Many of these passes outperform their counterparts from previous 13310 GCC releases. 13311 * [5]Swing Modulo Scheduling (SMS). An RTL level instruction 13312 scheduling optimization intended for loops that perform heavy 13313 computations. 13314 13315 New Languages and Language specific improvements 13316 13317 C family 13318 13319 * The sentinel attribute has been added to GCC. This function 13320 attribute allows GCC to warn when variadic functions such as execl 13321 are not NULL terminated. See the GCC manual for a complete 13322 description of its behavior. 13323 * Given __attribute__((alias("target"))) it is now an error if target 13324 is not a symbol, defined in the same translation unit. This also 13325 applies to aliases created by #pragma weak alias=target. This is 13326 because it's meaningless to define an alias to an undefined symbol. 13327 On Solaris, the native assembler would have caught this error, but 13328 GNU as does not. 13329 13330 C and Objective-C 13331 13332 * The -Wstrict-aliasing=2 option has been added. This warning catches 13333 all unsafe cases, but it may also give a warning for some cases 13334 that are safe. 13335 * The cast-as-lvalue, conditional-expression-as-lvalue and 13336 compound-expression-as-lvalue extensions, which were deprecated in 13337 3.3.4 and 3.4, have been removed. 13338 * The -fwritable-strings option, which was deprecated in 3.4, has 13339 been removed. 13340 * #pragma pack() semantics have been brought closer to those used by 13341 other compilers. This also applies to C++. 13342 * Taking the address of a variable with register storage is invalid 13343 in C. GCC now issues an error instead of a warning. 13344 * Arrays of incomplete element type are invalid in C. GCC now issues 13345 an error for such arrays. Declarations such as extern struct s x[]; 13346 (where struct s has not been defined) can be moved after the 13347 definition of struct s. Function parameters declared as arrays of 13348 incomplete type can instead be declared as pointers. 13349 13350 C++ 13351 13352 * When compiling without optimizations (-O0), the C++ front end is 13353 much faster than in any previous versions of GCC. Independent 13354 testers have measured speed-ups up to 25% in real-world production 13355 code, compared to the 3.4 family (which was already the fastest 13356 version to date). Upgrading from older versions might show even 13357 bigger improvements. 13358 * ELF visibility attributes can now be applied to a class type, so 13359 that it affects every member function of a class at once, without 13360 having to specify each individually: 13361 class __attribute__ ((visibility("hidden"))) Foo 13362 { 13363 int foo1(); 13364 void foo2(); 13365 }; 13366 The syntax is deliberately similar to the __declspec() system used 13367 by Microsoft Windows based compilers, allowing cross-platform 13368 projects to easily reuse their existing macro system for denoting 13369 exports and imports. By explicitly marking internal classes never 13370 used outside a binary as hidden, one can completely avoid PLT 13371 indirection overheads during their usage by the compiler. You can 13372 find out more about the advantages of this at 13373 [6]https://www.akkadia.org/drepper/dsohowto.pdf 13374 * The -fvisibility-inlines-hidden option has been added which marks 13375 all inlineable functions as having hidden ELF visibility, thus 13376 removing their symbol and typeinfo from the exported symbol table 13377 of the output ELF binary. Using this option can reduce the exported 13378 symbol count of template-heavy code by up to 40% with no code 13379 change at all, thus notably improving link and load times for the 13380 binary as well as a reduction in size of up to 10%. Also, check the 13381 new [7]-fvisibility option. 13382 * The compiler now uses the library interface specified by the [8]C++ 13383 ABI for thread-safe initialization of function-scope static 13384 variables. Most users should leave this alone, but embedded 13385 programmers may want to disable this by specifying 13386 -fno-threadsafe-statics for a small savings in code size. 13387 * Taking the address of an explicit register variable is no longer 13388 supported. Note that C++ allows taking the address of variables 13389 with register storage so this will continue to compile with a 13390 warning. For example, assuming that r0 is a machine register: 13391 register int foo asm ("r0"); 13392 register int bar; 13393 &foo; // error, no longer accepted 13394 &bar; // OK, with a warning 13395 * G++ has an undocumented extension to virtual function covariancy 13396 rules that allowed the overrider to return a type that was 13397 implicitly convertable to the overridden function's return type. 13398 For instance a function returning void * could be overridden by a 13399 function returning T *. This is now deprecated and will be removed 13400 in a future release. 13401 * The G++ minimum and maximum operators (<? and >?) and their 13402 compound forms (<?=) and >?=) have been deprecated and will be 13403 removed in a future version. Code using these operators should be 13404 modified to use std::min and std::max instead. 13405 * Declaration of nested classes of class templates as friends are 13406 supported: 13407 template <typename T> struct A { 13408 class B {}; 13409 }; 13410 class C { 13411 template <typename T> friend class A<T>::B; 13412 }; 13413 This complements the feature member functions of class templates as 13414 friends introduced in GCC 3.4.0. 13415 * When declaring a friend class using an unqualified name, classes 13416 outside the innermost non-class scope are not searched: 13417 class A; 13418 namespace N { 13419 class B { 13420 friend class A; // Refer to N::A which has not been declared yet 13421 // because name outside namespace N are not searched 13422 friend class ::A; // Refer to ::A 13423 }; 13424 } 13425 Hiding the friend name until declaration is still not implemented. 13426 * Friends of classes defined outside their namespace are correctly 13427 handled: 13428 namespace N { 13429 class A; 13430 } 13431 class N::A { 13432 friend class B; // Refer to N::B in GCC 4.0.0 13433 // but ::B in earlier versions of GCC 13434 }; 13435 13436 Runtime Library (libstdc++) 13437 13438 * Optimization work: 13439 + Added efficient specializations of istream functions for char 13440 and wchar_t. 13441 + Further performance tuning of strings, in particular wrt 13442 single-char append and getline. 13443 + iter_swap - and therefore most of the mutating algorithms - 13444 now makes an unqualified call to swap when the value_type of 13445 the two iterators is the same. 13446 * A large subset of the features in Technical Report 1 (TR1 for 13447 short) is experimentally delivered (i.e., no guarantees about the 13448 implementation are provided. In particular it is not promised that 13449 the library will remain link-compatible when code using TR1 is 13450 used): 13451 + General utilities such as reference_wrapper and shared_ptr. 13452 + Function objects, i.e., result_of, mem_fn, bind, function. 13453 + Support for metaprogramming. 13454 + New containers such as tuple, array, unordered_set, 13455 unordered_map, unordered_multiset, unordered_multimap. 13456 * As usual, many bugs have been fixed and LWG resolutions implemented 13457 for the first time (e.g., DR 409). 13458 13459 Java 13460 13461 * In order to prevent naming conflicts with other implementations of 13462 these tools, some GCJ binaries have been renamed: 13463 + rmic is now grmic, 13464 + rmiregistry is now grmiregistry, and 13465 + jar is now fastjar. 13466 In particular, these names were problematic for the jpackage.org 13467 packaging conventions which install symlinks in /usr/bin that point 13468 to the preferred versions of these tools. 13469 * The -findirect-dispatch argument to the compiler now works and 13470 generates code following a new "binary compatibility" ABI. Code 13471 compiled this way follows the binary compatibility rules of the 13472 Java Language Specification. 13473 * libgcj now has support for using GCJ as a JIT, using the 13474 gnu.gcj.jit family of system properties. 13475 * libgcj can now find a shared library corresponding to the bytecode 13476 representation of a class. See the documentation for the new 13477 gcj-dbtool program, and the new gnu.gcj.precompiled.db.path system 13478 property. 13479 * There have been many improvements to the class library. Here are 13480 some highlights: 13481 + Much more of AWT and Swing exist. 13482 + Many new packages and classes were added, including 13483 java.util.regex, java.net.URI, javax.crypto, 13484 javax.crypto.interfaces, javax.crypto.spec, javax.net, 13485 javax.net.ssl, javax.security.auth, 13486 javax.security.auth.callback, javax.security.auth.login, 13487 javax.security.auth.x500, javax.security.sasl, org.ietf.jgss, 13488 javax.imageio, javax.imageio.event, javax.imageio.spi, 13489 javax.print, javax.print.attribute, 13490 javax.print.attribute.standard, javax.print.event, and 13491 javax.xml 13492 + Updated SAX and DOM, and imported GNU JAXP 13493 13494 Fortran 13495 13496 * A new [9]Fortran front end has replaced the aging GNU Fortran 77 13497 front end. The new front end supports Fortran 90 and Fortran 95. It 13498 may not yet be as stable as the old Fortran front end. 13499 13500 Ada 13501 13502 * Ada (with tasking and Zero Cost Exceptions) is now available on 13503 many more targets, including but not limited to: alpha-linux, 13504 hppa-hpux, hppa-linux, powerpc-darwin, powerpc-linux, s390-linux, 13505 s390x-linux, sparc-linux. 13506 * Some of the new Ada 2005 features are now implemented like 13507 Wide_Wide_Character and Ada.Containers. 13508 * Many bugs have been fixed, tools and documentation improved. 13509 * To compile Ada from the sources, install an older working Ada 13510 compiler and then use --enable-languages=ada at configuration time, 13511 since the Ada front end is not currently activated by default. See 13512 the [10]Installing GCC for details. 13513 13514 New Targets and Target Specific Improvements 13515 13516 H8/300 13517 13518 * The frame layout has changed. In the new layout, the prologue of a 13519 function first saves registers and then allocate space for locals, 13520 resulting in an 1% improvement on code size. 13521 13522 IA-32/x86-64 (AMD64) 13523 13524 * The acos, asin, drem, exp10, exp2, expm1, fmod, ilogb, log10, 13525 log1p, log2, logb and tan mathematical builtins (and their float 13526 and long double variants) are now implemented as inline x87 13527 intrinsics when using -ffast-math. 13528 * The ceil, floor, nearbyint, rint and trunc mathematical builtins 13529 (and their float and long double variants) are now implemented as 13530 inline x87 intrinsics when using -ffast-math. 13531 * The x87's fsincos instruction is now used automatically with 13532 -ffast-math when calculating both the sin and cos of the same 13533 argument. 13534 * Instruction selection for multiplication and division by constants 13535 has been improved. 13536 13537 IA-64 13538 13539 * Floating point division, integer division and sqrt are now inlined, 13540 resulting in significant performance improvements on some codes. 13541 13542 MIPS 13543 13544 * Division by zero checks now use conditional traps if the target 13545 processor supports them. This decreases code size by one word per 13546 division operation. The old behavior (branch and break) can be 13547 obtained either at configure time by passing --with-divide=breaks 13548 to configure or at runtime by passing -mdivide-breaks to GCC. 13549 * Support for MIPS64 paired-single instructions has been added. It is 13550 enabled by -mpaired-single and can be accessed using both the 13551 target-independent vector extensions and new MIPS-specific built-in 13552 functions. 13553 * Support for the MIPS-3D ASE has been added. It is enabled by 13554 -mips3d and provides new MIPS-3D-specific built-in functions. 13555 * The -mexplicit-relocs option now supports static n64 code (as is 13556 used, for example, in 64-bit linux kernels). -mexplicit-relocs 13557 should now be feature-complete and is enabled by default when GCC 13558 is configured to use a compatible assembler. 13559 * Support for the NEC VR4130 series has been added. This support 13560 includes the use of VR-specific instructions and a new VR4130 13561 scheduler. Full VR4130 support can be selected with -march=vr4130 13562 while code for any ISA can be tuned for the VR4130 using 13563 -mtune=vr4130. There is also a new -mvr4130-align option that 13564 produces better schedules at the cost of increased code size. 13565 * Support for the Broadcom SB-1 has been extended. There is now an 13566 SB-1 scheduler as well as support for the SB-1-specific 13567 paired-single instructions. Full SB-1 support can be selected with 13568 -march=sb1 while code for any ISA can be optimized for the SB-1 13569 using -mtune=sb1. 13570 * The compiler can now work around errata in R4000, R4400, VR4120 and 13571 VR4130 processors. These workarounds are enabled by -mfix-r4000, 13572 -mfix-r4400, -mfix-vr4120 and -mfix-vr4130 respectively. The VR4120 13573 and VR4130 workarounds need binutils 2.16 or above. 13574 * IRIX shared libraries are now installed into the standard library 13575 directories: o32 libraries go into lib/, n32 libraries go into 13576 lib32/ and n64 libraries go into lib64/. 13577 * The compiler supports a new -msym32 option. It can be used to 13578 optimize n64 code in which all symbols are known to have 32-bit 13579 values. 13580 13581 S/390 and zSeries 13582 13583 * New command-line options help to generate code intended to run in 13584 an environment where stack space is restricted, e.g. Linux kernel 13585 code: 13586 + -mwarn-framesize and -mwarn-dynamicstack trigger compile-time 13587 warnings for single functions that require large or dynamic 13588 stack frames. 13589 + -mstack-size and -mstack-guard generate code that checks for 13590 stack overflow at run time. 13591 + -mpacked-stack generates code that reduces the stack frame 13592 size of many functions by reusing unneeded parts of the stack 13593 bias area. 13594 * The -msoft-float option now ensures that generated code never 13595 accesses floating point registers. 13596 * The s390x-ibm-tpf target now fully supports C++, including 13597 exceptions and threads. 13598 * Various changes to improve performance of the generated code have 13599 been implemented, including: 13600 + GCC now uses sibling calls where possible. 13601 + Condition code handling has been optimized, allowing GCC to 13602 omit redundant comparisons in certain cases. 13603 + The cost function guiding many optimizations has been refined 13604 to more accurately represent the z900 and z990 processors. 13605 + The ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL WITH BORROW 13606 instructions are now used to avoid conditional branches in 13607 certain cases. 13608 + The back end now uses the LEGITIMIZE_RELOAD_ADDRESS feature to 13609 optimize address arithmetic required to access large stack 13610 frames. 13611 + GCC now makes more efficient use of memory-to-memory type 13612 instructions (MVC, CLC, ...). 13613 + More precise tracking of special register use allows better 13614 instruction scheduling, in particular of the function prologue 13615 and epilogue sequences. 13616 + The Java front end now generates inline code to implement 13617 integer division, instead of calling library routines. 13618 13619 SPARC 13620 13621 * The options -mv8, -msparclite, -mcypress, -msupersparc, -mf930 and 13622 -mf934 have been removed. They have been replaced with -mcpu=xxx. 13623 * The internal model used to estimate the relative cost of each 13624 instruction has been updated. It is expected to give better results 13625 on recent UltraSPARC processors. 13626 * Code generation for function prologues and epilogues has been 13627 improved, resulting in better scheduling and allowing multiple exit 13628 points in functions. 13629 * Support for Sun's Visual Instruction Set (VIS) has been enhanced. 13630 It is enabled by -mvis and provides new built-in functions for VIS 13631 instructions on UltraSPARC processors. 13632 * The option -mapp-regs has been turned on by default on Solaris too. 13633 13634 NetWare 13635 13636 * Novell NetWare (on ix86, no other hardware platform was ever really 13637 supported by this OS) has been re-enabled and the ABI supported by 13638 GCC has been brought into sync with that of MetroWerks CodeWarrior 13639 (the ABI previously supported was that of some Unix systems, which 13640 NetWare never tried to support). 13641 13642 Obsolete Systems 13643 13644 Support for a number of older systems has been declared obsolete in GCC 13645 4.0. Unless there is activity to revive them, the next release of GCC 13646 will have their sources permanently removed. 13647 13648 All GCC ports for the following processor architectures have been 13649 declared obsolete: 13650 * Intel i860 13651 * Ubicom IP2022 13652 * National Semiconductor NS32K (ns32k) 13653 * Texas Instruments TMS320C[34]x 13654 13655 Also, those for some individual systems have been obsoleted: 13656 * SPARC family 13657 + SPARClite-based systems (sparclite-*-coff, sparclite-*-elf, 13658 sparc86x-*-elf) 13659 + OpenBSD 32-bit (sparc-*-openbsd*) 13660 13661 Documentation improvements 13662 13663 Other significant improvements 13664 13665 * Location lists are now generated by default when compiling with 13666 debug info and optimization. Location lists provide more accurate 13667 debug info about locations of variables and they allow debugging 13668 code compiled with -fomit-frame-pointer. 13669 * The -fvisibility option has been added which allows the default ELF 13670 visibility of all symbols to be set per compilation and the new 13671 #pragma GCC visibility preprocessor command allows the setting of 13672 default ELF visibility for a region of code. Using 13673 -fvisibility=hidden especially in combination with the new 13674 -fvisibility-inlines-hidden can yield substantial improvements in 13675 output binary quality including avoiding PLT indirection overheads, 13676 reduction of the exported symbol count by up to 60% (with resultant 13677 improvements to link and load times), better scope for the 13678 optimizer to improve code and up to a 20% reduction in binary size. 13679 Using these options correctly yields a binary with a similar symbol 13680 count to a Windows DLL. 13681 Perhaps more importantly, this new feature finally allows (with 13682 careful planning) complete avoidance of symbol clashes when 13683 manually loading shared objects with RTLD_GLOBAL, thus finally 13684 solving problems many projects such as python were forced to use 13685 RTLD_LOCAL for (with its resulting issues for C++ correctness). You 13686 can find more information about using these options at 13687 [11]https://gcc.gnu.org/wiki/Visibility. 13688 __________________________________________________________________ 13689 13690 GCC 4.0.1 13691 13692 This is the [12]list of problem reports (PRs) from GCC's bug tracking 13693 system that are known to be fixed in the 4.0.1 release. This list might 13694 not be complete (that is, it is possible that some PRs that have been 13695 fixed are not listed here). 13696 13697 GCC 4.0.2 13698 13699 This is the [13]list of problem reports (PRs) from GCC's bug tracking 13700 system that are known to be fixed in the 4.0.2 release. This list might 13701 not be complete (that is, it is possible that some PRs that have been 13702 fixed are not listed here). 13703 13704 Unfortunately, due to a release engineering failure, this release has a 13705 regression on Solaris that will affect some C++ programs. We suggest 13706 that Solaris users apply a [14]patch that corrects the problem. Users 13707 who do not wish to apply the patch should explicitly link C++ programs 13708 with the -pthreads option, even if they do not use threads. This 13709 problem has been corrected in the current 4.0 branch sources and will 13710 not be present in GCC 4.0.3. 13711 13712 GCC 4.0.3 13713 13714 Starting with this release, the function getcontext is recognized by 13715 the compiler as having the same semantics as the setjmp function. In 13716 particular, the compiler will ensure that all registers are dead before 13717 calling such a function and will emit a warning about the variables 13718 that may be clobbered after the second return from the function. 13719 13720 GCC 4.0.4 13721 13722 This is the [15]list of problem reports (PRs) from GCC's bug tracking 13723 system that are known to be fixed in the 4.0.4 release. This list might 13724 not be complete (that is, it is possible that some PRs that have been 13725 fixed are not listed here). 13726 13727 The 4.0.4 release is provided for those that require a high degree of 13728 binary compatibility with previous 4.0.x releases. For most users, the 13729 GCC team recommends that version 4.1.1 or later be used instead." 13730 13731 13732 For questions related to the use of GCC, please consult these web 13733 pages and the [16]GCC manuals. If that fails, the 13734 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13735 web pages and the development of GCC are welcome on our developer 13736 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 13737 archives. 13738 13739 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 13740 distribution of this entire article is permitted in any medium, 13741 provided this notice is preserved. 13742 13743 These pages are [21]maintained by the GCC team. Last modified 13744 2019-11-28[22]. 13745 13746 References 13747 13748 1. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4 13749 2. https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html 13750 3. http://gcc.gnu.org/projects/tree-ssa/ 13751 4. http://gcc.gnu.org/projects/tree-ssa/vectorization.html 13752 5. http://gcc.gnu.org/news/sms.html 13753 6. https://www.akkadia.org/drepper/dsohowto.pdf 13754 7. http://gcc.gnu.org/gcc-4.0/changes.html#visibility 13755 8. https://itanium-cxx-abi.github.io/cxx-abi/ 13756 9. http://gcc.gnu.org/fortran/ 13757 10. https://gcc.gnu.org/install/ 13758 11. https://gcc.gnu.org/wiki/Visibility 13759 12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.1 13760 13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.2 13761 14. https://gcc.gnu.org/ml/gcc-cvs/2005-09/msg00984.html 13762 15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.4 13763 16. https://gcc.gnu.org/onlinedocs/ 13764 17. mailto:gcc-help (a] gcc.gnu.org 13765 18. mailto:gcc (a] gcc.gnu.org 13766 19. https://gcc.gnu.org/lists.html 13767 20. https://www.fsf.org/ 13768 21. https://gcc.gnu.org/about.html 13769 22. http://validator.w3.org/check/referer 13770 ====================================================================== 13771 http://gcc.gnu.org/gcc-3.4/index.html 13772 13773 GCC 3.4 Release Series 13774 13775 (This release series is no longer supported.) 13776 13777 May 26, 2006 13778 13779 The [1]GNU project and the GCC developers are pleased to announce the 13780 release of GCC 3.4.6. 13781 13782 This release is a bug-fix release, containing fixes for regressions in 13783 GCC 3.4.4 relative to previous releases of GCC. This is the last of the 13784 3.4.x series. 13785 13786 The GCC 3.4 release series includes numerous [2]new features, 13787 improvements, bug fixes, and other changes, thanks to an [3]amazing 13788 group of volunteers. 13789 13790 Release History 13791 13792 GCC 3.4.6 13793 March 6, 2006 ([4]changes) 13794 13795 GCC 3.4.5 13796 November 30, 2005 ([5]changes) 13797 13798 GCC 3.4.4 13799 May 18, 2005 ([6]changes) 13800 13801 GCC 3.4.3 13802 November 4, 2004 ([7]changes) 13803 13804 GCC 3.4.2 13805 September 6, 2004 ([8]changes) 13806 13807 GCC 3.4.1 13808 July 1, 2004 ([9]changes) 13809 13810 GCC 3.4.0 13811 April 18, 2004 ([10]changes) 13812 13813 References and Acknowledgements 13814 13815 GCC used to stand for the GNU C Compiler, but since the compiler 13816 supports several other languages aside from C, it now stands for the 13817 GNU Compiler Collection. 13818 13819 A list of [11]successful builds is updated as new information becomes 13820 available. 13821 13822 The GCC developers would like to thank the numerous people that have 13823 contributed new features, improvements, bug fixes, and other changes as 13824 well as test results to GCC. This [12]amazing group of volunteers is 13825 what makes GCC successful. 13826 13827 For additional information about GCC please refer to the [13]GCC 13828 project web site or contact the [14]GCC development mailing list. 13829 13830 To obtain GCC please use [15]our mirror sites, or [16]our version 13831 control system. 13832 13833 13834 For questions related to the use of GCC, please consult these web 13835 pages and the [17]GCC manuals. If that fails, the 13836 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 13837 web pages and the development of GCC are welcome on our developer 13838 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 13839 archives. 13840 13841 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 13842 distribution of this entire article is permitted in any medium, 13843 provided this notice is preserved. 13844 13845 These pages are [22]maintained by the GCC team. Last modified 13846 2020-01-14[23]. 13847 13848 References 13849 13850 1. http://www.gnu.org/ 13851 2. http://gcc.gnu.org/gcc-3.4/changes.html 13852 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13853 4. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6 13854 5. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.5 13855 6. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.4 13856 7. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.3 13857 8. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.2 13858 9. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.1 13859 10. http://gcc.gnu.org/gcc-3.4/changes.html 13860 11. http://gcc.gnu.org/gcc-3.4/buildstat.html 13861 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 13862 13. http://gcc.gnu.org/index.html 13863 14. mailto:gcc (a] gcc.gnu.org 13864 15. http://gcc.gnu.org/mirrors.html 13865 16. http://gcc.gnu.org/git.html 13866 17. https://gcc.gnu.org/onlinedocs/ 13867 18. mailto:gcc-help (a] gcc.gnu.org 13868 19. mailto:gcc (a] gcc.gnu.org 13869 20. https://gcc.gnu.org/lists.html 13870 21. https://www.fsf.org/ 13871 22. https://gcc.gnu.org/about.html 13872 23. http://validator.w3.org/check/referer 13873 ====================================================================== 13874 http://gcc.gnu.org/gcc-3.4/changes.html 13875 13876 GCC 3.4 Release Series 13877 Changes, New Features, and Fixes 13878 13879 The final release in the 3.4 release series is [1]GCC 3.4.6. The series 13880 is now closed. 13881 13882 GCC 3.4 has [2]many improvements in the C++ front end. Before reporting 13883 a bug, please make sure it's really GCC, and not your code, that is 13884 broken. 13885 13886 Caveats 13887 13888 * GNU Make is now required to build GCC. 13889 * With -nostdinc the preprocessor used to ignore both standard 13890 include paths and include paths contained in environment variables. 13891 It was neither documented nor intended that environment variable 13892 paths be ignored, so this has been corrected. 13893 * GCC no longer accepts the options -fvolatile, -fvolatile-global and 13894 -fvolatile-static. It is unlikely that they worked correctly in any 13895 3.x release. 13896 * GCC no longer ships <varargs.h>. Use <stdarg.h> instead. 13897 * Support for all the systems [3]obsoleted in GCC 3.3 has been 13898 removed from GCC 3.4. See below for a [4]list of systems which are 13899 obsoleted in this release. 13900 * GCC now requires an ISO C90 (ANSI C89) C compiler to build. K&R C 13901 compilers will not work. 13902 * The implementation of the [5]MIPS ABIs has changed. As a result, 13903 the code generated for certain MIPS targets will not be binary 13904 compatible with earlier releases. 13905 * In previous releases, the MIPS port had a fake "hilo" register with 13906 the user-visible name accum. This register has been removed. 13907 * The implementation of the [6]SPARC ABIs has changed. As a result, 13908 the code generated will not be binary compatible with earlier 13909 releases in certain cases. 13910 * The configure option --enable-threads=pthreads has been removed; 13911 use --enable-threads=posix instead, which should have the same 13912 effect. 13913 * Code size estimates used by inlining heuristics for C, Objective-C, 13914 C++ and Java have been redesigned significantly. As a result the 13915 parameters of -finline-insns, --param max-inline-insns-single and 13916 --param max-inline-insns-auto need to be reconsidered. 13917 * --param max-inline-slope and --param min-inline-insns have been 13918 removed; they are not needed for the new bottom-up inlining 13919 heuristics. 13920 * The new unit-at-a-time compilation scheme has several compatibility 13921 issues: 13922 + The order in which functions, variables, and top-level asm 13923 statements are emitted may have changed. Code relying on some 13924 particular ordering needs to be updated. The majority of such 13925 top-level asm statements can be replaced by section 13926 attributes. 13927 + Unreferenced static variables and functions are removed. This 13928 may result in undefined references when an asm statement 13929 refers to the variable/function directly. In that case either 13930 the variable/function shall be listed in asm statement operand 13931 or in the case of top-level asm statements the attribute used 13932 shall be used to force function/variable to be always output 13933 and considered as a possibly used by unknown code. 13934 For variables the attribute is accepted only by GCC 3.4 and 13935 newer, while for earlier versions it is sufficient to use 13936 unused to silence warnings about the variables not being 13937 referenced. To keep code portable across different GCC 13938 versions, you can use appropriate preprocessor conditionals. 13939 + Static functions now can use non-standard passing conventions 13940 that may break asm statements calling functions directly. 13941 Again the attribute used shall be used to prevent this 13942 behavior. 13943 As a temporary workaround, -fno-unit-at-a-time can be used, but 13944 this scheme may not be supported by future releases of GCC. 13945 * GCC 3.4 automatically places zero-initialized variables in the .bss 13946 section on some operating systems. Versions of GNU Emacs up to (and 13947 including) 21.3 will not work correctly when using this 13948 optimization; you can use -fno-zero-initialized-in-bss to disable 13949 it. 13950 * If GCC 3.4 is configured with --enable-threads=posix (the default 13951 on most targets that support pthreads) then _REENTRANT will be 13952 defined unconditionally by some libstdc++ headers. C++ code which 13953 relies on that macro to detect whether multi-threaded code is being 13954 compiled might change in meaning, possibly resulting in linker 13955 errors for single-threaded programs. Affected users of [7]Boost 13956 should compile single-threaded code with -DBOOST_DISABLE_THREADS. 13957 See Bugzilla for [8]more information. 13958 13959 General Optimizer Improvements 13960 13961 * Usability of the profile feedback and coverage testing has been 13962 improved. 13963 + Performance of profiled programs has been improved by faster 13964 profile merging code. 13965 + Better use of the profile feedback for optimization (loop 13966 unrolling and loop peeling). 13967 + File locking support allowing fork() calls and parallel runs 13968 of profiled programs. 13969 + Coverage file format has been redesigned. 13970 + gcov coverage tool has been improved. 13971 + make profiledbootstrap available to build a faster compiler. 13972 Experiments made on i386 hardware showed an 11% speedup on -O0 13973 and a 7.5% speedup on -O2 compilation of a [9]large C++ 13974 testcase. 13975 + New value profiling pass enabled via -fprofile-values 13976 + New value profile transformations pass enabled via -fvpt aims 13977 to optimize some code sequences by exploiting knowledge about 13978 value ranges or other properties of the operands. At the 13979 moment a conversion of expensive divisions into cheaper 13980 operations has been implemented. 13981 + New -fprofile-generate and -fprofile-use command-line options 13982 to simplify the use of profile feedback. 13983 * A new unit-at-a-time compilation scheme for C, Objective-C, C++ and 13984 Java which is enabled via -funit-at-a-time (and implied by -O2). In 13985 this scheme a whole file is parsed first and optimized later. The 13986 following basic inter-procedural optimizations are implemented: 13987 + Removal of unreachable functions and variables 13988 + Discovery of local functions (functions with static linkage 13989 whose address is never taken) 13990 + On i386, these local functions use register parameter passing 13991 conventions. 13992 + Reordering of functions in topological order of the call graph 13993 to enable better propagation of optimizing hints (such as the 13994 stack alignments needed by functions) in the back end. 13995 + Call graph based out-of-order inlining heuristics which allows 13996 to limit overall compilation unit growth (--param 13997 inline-unit-growth). 13998 Overall, the unit-at-a-time scheme produces a 1.3% improvement for 13999 the SPECint2000 benchmark on the i386 architecture (AMD Athlon 14000 CPU). 14001 * More realistic code size estimates used by inlining for C, 14002 Objective-C, C++ and Java. The growth of large functions can now be 14003 limited via --param large-function-insns and --param 14004 large-function-growth. 14005 * A new cfg-level loop optimizer pass replaces the old loop unrolling 14006 pass and adds two other loop transformations -- loop peeling and 14007 loop unswitching -- and also uses the profile feedback to limit 14008 code growth. (The three optimizations are enabled by 14009 -funroll-loops, -fpeel-loops and -funswitch-loops flags, 14010 respectively). 14011 The old loop unroller still can be enabled by -fold-unroll-loops 14012 and may produce better code in some cases, especially when the 14013 webizer optimization pass is not run. 14014 * A new web construction pass enabled via -fweb (and implied by -O3) 14015 improves the quality of register allocation, CSE, first scheduling 14016 pass and some other optimization passes by avoiding re-use of 14017 pseudo registers with non-overlapping live ranges. The pass almost 14018 always improves code quality but does make debugging difficult and 14019 thus is not enabled by default by -O2 14020 The pass is especially effective as cleanup after code duplication 14021 passes, such as the loop unroller or the tracer. 14022 * Experimental implementations of superblock or trace scheduling in 14023 the second scheduling pass can be enabled via 14024 -fsched2-use-superblocks and -fsched2-use-traces, respectively. 14025 14026 New Languages and Language specific improvements 14027 14028 Ada 14029 14030 * The Ada front end has been updated to include numerous bug fixes 14031 and enhancements. These include: 14032 + Improved project file support 14033 + Additional set of warnings about potential wrong code 14034 + Improved error messages 14035 + Improved code generation 14036 + Improved cross reference information 14037 + Improved inlining 14038 + Better run-time check elimination 14039 + Better error recovery 14040 + More efficient implementation of unbounded strings 14041 + Added features in GNAT.Sockets, GNAT.OS_Lib, GNAT.Debug_Pools, 14042 ... 14043 + New GNAT.xxxx packages (e.g. GNAT.Strings, 14044 GNAT.Exception_Action) 14045 + New pragmas 14046 + New -gnatS switch replacing gnatpsta 14047 + Implementation of new Ada features (in particular limited 14048 with, limited aggregates) 14049 14050 C/Objective-C/C++ 14051 14052 * Precompiled headers are now supported. Precompiled headers can 14053 dramatically speed up compilation of some projects. There are some 14054 known defects in the current precompiled header implementation that 14055 will result in compiler crashes in relatively rare situations. 14056 Therefore, precompiled headers should be considered a "technology 14057 preview" in this release. Read the manual for details about how to 14058 use precompiled headers. 14059 * File handling in the preprocessor has been rewritten. GCC no longer 14060 gets confused by symlinks and hardlinks, and now has a correct 14061 implementation of #import and #pragma once. These two directives 14062 have therefore been un-deprecated. 14063 * The undocumented extension that allowed C programs to have a label 14064 at the end of a compound statement, which has been deprecated since 14065 GCC 3.0, has been removed. 14066 * The cast-as-lvalue extension has been removed for C++ and 14067 deprecated for C and Objective-C. In particular, code like this: 14068 int i; 14069 (char) i = 5; 14070 14071 or this: 14072 char *p; 14073 ((int *) p)++; 14074 14075 is no longer accepted for C++ and will not be accepted for C and 14076 Objective-C in a future version. 14077 * The conditional-expression-as-lvalue extension has been deprecated 14078 for C and Objective-C. In particular, code like this: 14079 int a, b, c; 14080 (a ? b : c) = 2; 14081 14082 will not be accepted for C and Objective-C in a future version. 14083 * The compound-expression-as-lvalue extension has been deprecated for 14084 C and Objective-C. In particular, code like this: 14085 int a, b; 14086 (a, b) = 2; 14087 14088 will not be accepted for C and Objective-C in a future version. A 14089 possible non-intrusive workaround is the following: 14090 (*(a, &b)) = 2; 14091 14092 * Several [10]built-in functions such as __builtin_popcount for 14093 counting bits, finding the highest and lowest bit in a word, and 14094 parity have been added. 14095 * The -fwritable-strings option has been deprecated and will be 14096 removed. 14097 * Many C math library functions are now recognized as built-ins and 14098 optimized. 14099 * The C, C++, and Objective-C compilers can now handle source files 14100 written in any character encoding supported by the host C library. 14101 The default input character set is taken from the current locale, 14102 and may be overridden with the -finput-charset command line option. 14103 In the future we will add support for inline encoding markers. 14104 14105 C++ 14106 14107 * G++ is now much closer to full conformance to the ISO/ANSI C++ 14108 standard. This means, among other things, that a lot of invalid 14109 constructs which used to be accepted in previous versions will now 14110 be rejected. It is very likely that existing C++ code will need to 14111 be fixed. This document lists some of the most common issues. 14112 * A hand-written recursive-descent C++ parser has replaced the 14113 YACC-derived C++ parser from previous GCC releases. The new parser 14114 contains much improved infrastructure needed for better parsing of 14115 C++ source codes, handling of extensions, and clean separation 14116 (where possible) between proper semantics analysis and parsing. The 14117 new parser fixes many bugs that were found in the old parser. 14118 * You must now use the typename and template keywords to disambiguate 14119 dependent names, as required by the C++ standard. 14120 struct K { 14121 typedef int mytype_t; 14122 }; 14123 14124 template <class T1> struct A { 14125 template <class T2> struct B { 14126 void callme(void); 14127 }; 14128 14129 template <int N> void bar(void) 14130 { 14131 // Use 'typename' to tell the parser that T1::mytype_t names 14132 // a type. This is needed because the name is dependent (in 14133 // this case, on template parameter T1). 14134 typename T1::mytype_t x; 14135 x = 0; 14136 } 14137 }; 14138 14139 template <class T> void template_func(void) 14140 { 14141 // Use 'template' to prefix member templates within 14142 // dependent types (a has type A<T>, which depends on 14143 // the template parameter T). 14144 A<T> a; 14145 a.template bar<0>(); 14146 14147 // Use 'template' to tell the parser that B is a nested 14148 // template class (dependent on template parameter T), and 14149 // 'typename' because the whole A<T>::B<int> is 14150 // the name of a type (again, dependent). 14151 typename A<T>::template B<int> b; 14152 b.callme(); 14153 } 14154 14155 void non_template_func(void) 14156 { 14157 // Outside of any template class or function, no names can be 14158 // dependent, so the use of the keyword 'typename' and 'template' 14159 // is not needed (and actually forbidden). 14160 A<K> a; 14161 a.bar<0>(); 14162 A<K>::B<float> b; 14163 b.callme(); 14164 } 14165 * In a template definition, unqualified names will no longer find 14166 members of a dependent base (as specified by [temp.dep]/3 in the 14167 C++ standard). For example, 14168 template <typename T> struct B { 14169 int m; 14170 int n; 14171 int f (); 14172 int g (); 14173 }; 14174 int n; 14175 int g (); 14176 template <typename T> struct C : B<T> { 14177 void h () 14178 { 14179 m = 0; // error 14180 f (); // error 14181 n = 0; // ::n is modified 14182 g (); // ::g is called 14183 } 14184 }; 14185 You must make the names dependent, e.g. by prefixing them with 14186 this->. Here is the corrected definition of C<T>::h, 14187 template <typename T> void C<T>::h () 14188 { 14189 this->m = 0; 14190 this->f (); 14191 this->n = 0 14192 this->g (); 14193 } 14194 As an alternative solution (unfortunately not backwards compatible 14195 with GCC 3.3), you may use using declarations instead of this->: 14196 template <typename T> struct C : B<T> { 14197 using B<T>::m; 14198 using B<T>::f; 14199 using B<T>::n; 14200 using B<T>::g; 14201 void h () 14202 { 14203 m = 0; 14204 f (); 14205 n = 0; 14206 g (); 14207 } 14208 }; 14209 * In templates, all non-dependent names are now looked up and bound 14210 at definition time (while parsing the code), instead of later when 14211 the template is instantiated. For instance: 14212 void foo(int); 14213 14214 template <int> struct A { 14215 static void bar(void){ 14216 foo('a'); 14217 } 14218 }; 14219 14220 void foo(char); 14221 14222 int main() 14223 { 14224 A<0>::bar(); // Calls foo(int), used to call foo(char). 14225 } 14226 14227 * In an explicit instantiation of a class template, you must use 14228 class or struct before the template-id: 14229 template <int N> 14230 class A {}; 14231 14232 template A<0>; // error, not accepted anymore 14233 template class A<0>; // OK 14234 * The "named return value" and "implicit typename" extensions have 14235 been removed. 14236 * Default arguments in function types have been deprecated and will 14237 be removed. 14238 * ARM-style name-injection of friend declarations has been deprecated 14239 and will be removed. For example: struct S { friend void f(); }; 14240 void g() { f(); } will not be accepted by future versions of G++; 14241 instead a declaration of "f" will need to be present outside of the 14242 scope of "S". 14243 * Covariant returns are implemented for all but varadic functions 14244 that require an adjustment. 14245 * When -pedantic is used, G++ now issues errors about spurious 14246 semicolons. For example, 14247 namespace N {}; // Invalid semicolon. 14248 void f() {}; // Invalid semicolon. 14249 * G++ no longer accepts attributes for a declarator after the 14250 initializer associated with that declarator. For example, 14251 X x(1) __attribute__((...)); 14252 is no longer accepted. Instead, use: 14253 X x __attribute__((...)) (1); 14254 * Inside the scope of a template class, the name of the class itself 14255 can be treated as either a class or a template. So GCC used to 14256 accept the class name as argument of type template, and template 14257 template parameter. However this is not C++ standard compliant. Now 14258 the name is not treated as a valid template template argument 14259 unless you qualify the name by its scope. For example, the code 14260 below no longer compiles. 14261 template <template <class> class TT> class X {}; 14262 template <class T> class Y { 14263 X<Y> x; // Invalid, Y is always a type template parameter. 14264 }; 14265 The valid code for the above example is 14266 X< ::Y> x; // Valid. 14267 (Notice the space between < and : to prevent GCC to interpret this 14268 as a digraph for [.) 14269 * Friend declarations that refer to template specializations are 14270 rejected if the template has not already been declared. For 14271 example, 14272 template <typename T> 14273 class C { 14274 friend void f<> (C&); 14275 }; 14276 is rejected. You must first declare f as a template, 14277 template <typename T> 14278 void f(T); 14279 * In case of friend declarations, every name used in the friend 14280 declaration must be accessible at the point of that declaration. 14281 Previous versions of G++ used to be less strict about this and 14282 allowed friend declarations for private class members, for example. 14283 See the ISO C++ Standard Committee's [11]defect report #209 for 14284 details. 14285 * Declaration of member functions of class templates as friends are 14286 supported. For example, 14287 template <typename T> struct A { 14288 void f(); 14289 }; 14290 class C { 14291 template <typename T> friend void A<T>::f(); 14292 }; 14293 * You must use template <> to introduce template specializations, as 14294 required by the standard. For example, 14295 template <typename T> 14296 struct S; 14297 14298 struct S<int> { }; 14299 is rejected. You must write, 14300 template <> struct S<int> {}; 14301 * G++ used to accept code like this, 14302 struct S { 14303 int h(); 14304 void f(int i = g()); 14305 int g(int i = h()); 14306 }; 14307 This behavior is not mandated by the standard. Now G++ issues an 14308 error about this code. To avoid the error, you must move the 14309 declaration of g before the declaration of f. The default arguments 14310 for g must be visible at the point where it is called. 14311 * The C++ ABI Section 3.3.3 specifications for the array construction 14312 routines __cxa_vec_new2 and __cxa_vec_new3 were changed to return 14313 NULL when the allocator argument returns NULL. These changes are 14314 incorporated into the libstdc++ runtime library. 14315 * Using a name introduced by a typedef in a friend declaration or in 14316 an explicit instantiation is now rejected, as specified by the ISO 14317 C++ standard. 14318 class A; 14319 typedef A B; 14320 class C { 14321 friend class B; // error, no typedef name here 14322 friend B; // error, friend always needs class/struct/enum 14323 friend class A; // OK 14324 }; 14325 14326 template <int> class Q {}; 14327 typedef Q<0> R; 14328 template class R; // error, no typedef name here 14329 template class Q<0>; // OK 14330 * When allocating an array with a new expression, GCC used to allow 14331 parentheses around the type name. This is actually ill-formed and 14332 it is now rejected: 14333 int* a = new (int)[10]; // error, not accepted anymore 14334 int* a = new int[10]; // OK 14335 * When binding an rvalue of class type to a reference, the copy 14336 constructor of the class must be accessible. For instance, consider 14337 the following code: 14338 class A 14339 { 14340 public: 14341 A(); 14342 14343 private: 14344 A(const A&); // private copy ctor 14345 }; 14346 14347 A makeA(void); 14348 void foo(const A&); 14349 14350 void bar(void) 14351 { 14352 foo(A()); // error, copy ctor is not accessible 14353 foo(makeA()); // error, copy ctor is not accessible 14354 14355 A a1; 14356 foo(a1); // OK, a1 is a lvalue 14357 } 14358 This might be surprising at first sight, especially since most 14359 popular compilers do not correctly implement this rule ([12]further 14360 details). 14361 * When forming a pointer to member or a pointer to member function, 14362 access checks for class visibility (public, protected, private) are 14363 now performed using the qualifying scope of the name itself. This 14364 is better explained with an example: 14365 class A 14366 { 14367 public: 14368 void pub_func(); 14369 protected: 14370 void prot_func(); 14371 private: 14372 void priv_func(); 14373 }; 14374 14375 class B : public A 14376 { 14377 public: 14378 void foo() 14379 { 14380 &A::pub_func; // OK, pub_func is accessible through A 14381 &A::prot_func; // error, cannot access prot_func through A 14382 &A::priv_func; // error, cannot access priv_func through A 14383 14384 &B::pub_func; // OK, pub_func is accessible through B 14385 &B::prot_func; // OK, can access prot_func through B (within B) 14386 &B::priv_func; // error, cannot access priv_func through B 14387 } 14388 }; 14389 14390 Runtime Library (libstdc++) 14391 14392 * Optimization work: 14393 + Streamlined streambuf, filebuf, separate synched with C 14394 Standard I/O streambuf. 14395 + All formatted I/O now uses cached locale information. 14396 + STL optimizations (memory/speed for list, red-black trees as 14397 used by sets and maps). 14398 + More use of GCC builtins. 14399 + String optimizations (avoid contention on 14400 increment/decrement-and-test of the reference count in the 14401 empty-string object, constructor from input_iterators 14402 speedup). 14403 * Static linkage size reductions. 14404 * Large File Support (files larger than 2 GB on 32-bit systems). 14405 * Wide character and variable encoding filebuf work (UTF-8, Unicode). 14406 * Generic character traits. 14407 * Also support wchar_t specializations on Mac OS 10.3.x, FreeBSD 5.x, 14408 Solaris 2.7 and above, AIX 5.x, Irix 6.5. 14409 * The allocator class is now standard-conformant, and two additional 14410 extension allocators have been added, mt_alloc and 14411 bitmap_allocator. 14412 * PCH support: -include bits/stdc++.h (2x compile speedup). 14413 * Rewrote __cxa_demangle with support for C++ style allocators. 14414 * New debug modes for STL containers and iterators. 14415 * Testsuite rewrite: five times as many tests, plus increasingly 14416 sophisticated tests, including I/O, MT, multi-locale, wide and 14417 narrow characters. 14418 * Use current versions of GNU "autotools" for build/configuration. 14419 14420 Objective-C 14421 14422 * The Objective-C front end has been updated to include the numerous 14423 bug fixes and enhancements previously available only in Apple's 14424 version of GCC. These include: 14425 + Structured exception (@try... @catch... @finally, @throw) and 14426 synchronization (@synchronized) support. These are accessible 14427 via the -fobjc-exceptions switch; as of this writing, they may 14428 only be used in conjunction with -fnext-runtime on Mac OS X 14429 10.3 and later. See [13]Options Controlling Objective-C 14430 Dialect for more information. 14431 + An overhaul of @encode logic. The C99 _Bool and C++ bool type 14432 may now be encoded as 'B'. In addition, the back-end/codegen 14433 dependencies have been removed. 14434 + An overhaul of message dispatch construction, ensuring that 14435 the various receiver types (and casts thereof) are handled 14436 properly, and that correct diagnostics are issued. 14437 + Support for "Zero-Link" (-fzero-link) and "Fix-and-Continue" 14438 (-freplace-objc-classes) debugging modes, currently available 14439 on Mac OS X 10.3 and later. See [14]Options Controlling 14440 Objective-C Dialect for more information. 14441 + Access to optimized runtime entry points (-fno-nil-receivers ) 14442 on the assumption that message receivers are never nil. This 14443 is currently available on Mac OS X 10.3 and later. See 14444 [15]Options Controlling Objective-C Dialect for more 14445 information. 14446 14447 Java 14448 14449 * Compiling a .jar file will now cause non-.class entries to be 14450 automatically compiled as resources. 14451 * libgcj has been ported to Darwin. 14452 * Jeff Sturm has adapted Jan Hubicka's call graph optimization code 14453 to gcj. 14454 * libgcj has a new gcjlib URL type; this lets URLClassLoader load 14455 code from shared libraries. 14456 * libgcj has been much more completely merged with [16]GNU Classpath. 14457 * Class loading is now much more correct; in particular the caller's 14458 class loader is now used when that is required. 14459 * [17]Eclipse 2.x will run out of the box using gij. 14460 * Parts of java.nio have been implemented. Direct and indirect 14461 buffers work, as do fundamental file and socket operations. 14462 * java.awt has been improved, though it is still not ready for 14463 general use. 14464 * The HTTP protocol handler now uses HTTP/1.1 and can handle the POST 14465 method. 14466 * The MinGW port has matured. Enhancements include socket timeout 14467 support, thread interruption, improved Runtime.exec() handling and 14468 support for accented characters in filenames. 14469 14470 Fortran 14471 14472 * Fortran improvements are listed in the [18]Fortran documentation. 14473 14474 New Targets and Target Specific Improvements 14475 14476 Alpha 14477 14478 * Several [19]built-in functions have been added such as 14479 __builtin_alpha_zap to allow utilizing the more obscure 14480 instructions of the CPU. 14481 * Parameter passing of complex arguments has changed to match the 14482 ABI. This change is incompatible with previous GCC versions, but 14483 does fix compatibility with the Tru64 compiler and several corner 14484 cases where GCC was incompatible with itself. 14485 14486 ARM 14487 14488 * Nicolas Pitre has contributed his hand-coded floating-point support 14489 code for ARM. It is both significantly smaller and faster than the 14490 existing C-based implementation, even when building applications 14491 for Thumb. The arm-elf configuration has been converted to use the 14492 new code. 14493 * Support for the Intel's iWMMXt architecture, a second generation 14494 XScale processor, has been added. Enabled at run time with the 14495 -mcpu=iwmmxt command line switch. 14496 * A new ARM target has been added: arm-wince-pe. This is similar to 14497 the arm-pe target, but it defaults to using the APCS32 ABI. 14498 * The existing ARM pipeline description has been converted to the use 14499 the [20]DFA processor pipeline model. There is not much change in 14500 code performance, but the description is now [21]easier to 14501 understand. 14502 * Support for the Cirrus EP9312 Maverick floating point co-processor 14503 added. Enabled at run time with the -mcpu=ep9312 command line 14504 switch. Note however that the multilibs to support this chip are 14505 currently disabled in gcc/config/arm/t-arm-elf, so if you want to 14506 enable their production you will have to uncomment the entries in 14507 that file. 14508 14509 H8/300 14510 14511 * Support for long long has been added. 14512 * Support for saveall attribute has been added. 14513 * Pavel Pisa contributed hand-written 32-bit-by-32-bit division code 14514 for H8/300H and H8S, which is much faster than the previous 14515 implementation. 14516 * A lot of small performance improvements. 14517 14518 IA-32/AMD64 (x86-64) 14519 14520 * Tuning for K8 (AMD Opteron/Athlon64) core is available via 14521 -march=k8 and -mcpu=k8. 14522 * Scalar SSE code generation carefully avoids reformatting penalties, 14523 hidden dependencies and minimizes the number of uops generated on 14524 both Intel and AMD CPUs. 14525 * Vector MMX and SSE operands are now passed in registers to improve 14526 performance and match the argument passing convention used by the 14527 Intel C++ Compiler. As a result it is not possible to call 14528 functions accepting vector arguments compiled by older GCC version. 14529 * Conditional jump elimination is now more aggressive on modern CPUs. 14530 * The Athlon ports has been converted to use the DFA processor 14531 pipeline description. 14532 * Optimization of indirect tail calls is now possible in a similar 14533 fashion as direct sibcall optimization. 14534 * Further small performance improvements. 14535 * -m128bit-long-double is now less buggy. 14536 * __float128 support in 64-bit compilation. 14537 * Support for data structures exceeding 2GB in 64-bit mode. 14538 * -mcpu has been renamed to -mtune. 14539 14540 IA-64 14541 14542 * Tuning code for the Itanium 2 processor has been added. The 14543 generation of code tuned for Itanium 2 (option -mtune=itanium2) is 14544 enabled by default now. To generate code tuned for Itanium 1 the 14545 option -mtune=itanium1 should be used. 14546 * [22]DFA processor pipeline descriptions for the IA-64 processors 14547 have been added. This resulted in about 3% improvement on the 14548 SPECInt2000 benchmark for Itanium 2. 14549 * Instruction bundling for the IA-64 processors has been rewritten 14550 using the DFA pipeline hazard recognizer. It resulted in about 60% 14551 compiler speedup on the SPECInt2000 C programs. 14552 14553 M32R 14554 14555 * Support for the M32R/2 processor has been added by Renesas. 14556 * Support for an M32R GNU/Linux target and PIC code generation has 14557 been added by Renesas. 14558 14559 M68000 14560 14561 * Bernardo Innocenti (Develer S.r.l.) has contributed the 14562 m68k-uclinux target, based on former work done by Paul Dale 14563 (SnapGear Inc.). Code generation for the ColdFire processors family 14564 has been enhanced and extended to support the MCF 53xx and MCF 54xx 14565 cores, integrating former work done by Peter Barada (Motorola). 14566 14567 MIPS 14568 14569 Processor-specific changes 14570 14571 * Support for the RM7000 and RM9000 processors has been added. It can 14572 be selected using the -march compiler option and should work with 14573 any MIPS I (mips-*) or MIPS III (mips64-*) configuration. 14574 * Support for revision 2 of the MIPS32 ISA has been added. It can be 14575 selected with the command-line option -march=mips32r2. 14576 * There is a new option, -mfix-sb1, to work around certain SB-1 14577 errata. 14578 14579 Configuration 14580 14581 * It is possible to customize GCC using the following configure-time 14582 options: 14583 + --with-arch, which specifies the default value of the -march 14584 option. 14585 + --with-tune, which specifies the default value of the -mtune 14586 option. 14587 + --with-abi, which specifies the default ABI. 14588 + --with-float=soft, which tells GCC to use software floating 14589 point by default. 14590 + --with-float=hard, which tells GCC to use hardware floating 14591 point by default. 14592 * A 64-bit GNU/Linux port has been added. The associated 14593 configurations are mips64-linux-gnu and mips64el-linux-gnu. 14594 * The 32-bit GNU/Linux port now supports Java. 14595 * The IRIX 6 configuration now supports the o32 ABI and will build 14596 o32 multilibs by default. This support is compatible with both 14597 binutils and the SGI tools, but note that several features, 14598 including debugging information and DWARF2 exception handling, are 14599 only available when using the GNU assembler. Use of the GNU 14600 assembler and linker (version 2.15 or above) is strongly 14601 recommended. 14602 * The IRIX 6 configuration now supports 128-bit long doubles. 14603 * There are two new RTEMS-specific configurations, mips-rtems and 14604 mipsel-rtems. 14605 * There are two new *-elf configurations, mipsisa32r2-elf and 14606 mipsisa32r2el-elf. 14607 14608 General 14609 14610 * Several [23]ABI bugs have been fixed. Unfortunately, these changes 14611 will break binary compatibility with earlier releases. 14612 * GCC can now use explicit relocation operators when generating 14613 -mabicalls code. This behavior is controlled by -mexplicit-relocs 14614 and can have several performance benefits. For example: 14615 + It allows for more optimization of GOT accesses, including 14616 better scheduling and redundancy elimination. 14617 + It allows sibling calls to be implemented as jumps. 14618 + n32 and n64 leaf functions can use a call-clobbered global 14619 pointer instead of $28. 14620 + The code to set up $gp can be removed from functions that 14621 don't need it. 14622 * A new option, -mxgot, allows the GOT to be bigger than 64k. This 14623 option is equivalent to the assembler's -xgot option and should be 14624 used instead of -Wa,-xgot. 14625 * Frame pointer elimination is now supported when generating 64-bit 14626 MIPS16 code. 14627 * Inline block moves have been optimized to take more account of 14628 alignment information. 14629 * Many internal changes have been made to the MIPS port, mostly aimed 14630 at reducing the reliance on assembler macros. 14631 14632 PowerPC 14633 14634 * GCC 3.4 releases have a number of fixes for PowerPC and PowerPC64 14635 [24]ABI incompatibilities regarding the way parameters are passed 14636 during functions calls. These changes may result in incompatibility 14637 between code compiled with GCC 3.3 and GCC 3.4. 14638 14639 PowerPC Darwin 14640 14641 * Support for shared/dylib gcc libraries has been added. It is 14642 enabled by default on powerpc-apple-darwin7.0.0 and up. 14643 * Libgcj is enabled by default. On systems older than 14644 powerpc-apple-darwin7.0.0 you need to install dlcompat. 14645 * 128-bit IBM extended precision format support added for long 14646 double. 14647 14648 PowerPC64 GNU/Linux 14649 14650 * By default, PowerPC64 GNU/Linux now uses natural alignment of 14651 structure elements. The old four byte alignment for double, with 14652 special rules for a struct starting with a double, can be chosen 14653 with -malign-power. This change may result in incompatibility 14654 between code compiled with GCC 3.3 and GCC 3.4. 14655 * -mabi=altivec is now the default rather than -mabi=no-altivec. 14656 * 128-bit IBM extended precision format support added for long 14657 double. 14658 14659 S/390 and zSeries 14660 14661 * New command-line options allow to specify the intended execution 14662 environment for generated code: 14663 + -mesa/-mzarch allows to specify whether to generate code 14664 running in ESA/390 mode or in z/Architecture mode (this is 14665 applicable to 31-bit code only). 14666 + -march allows to specify a minimum processor architecture 14667 level (g5, g6, z900, or z990). 14668 + -mtune allows to specify which processor to tune for. 14669 * It is possible to customize GCC using the following configure-time 14670 options: 14671 + --with-mode, which specifies whether to default to assuming 14672 ESA/390 or z/Architecture mode. 14673 + --with-arch, which specifies the default value of the -march 14674 option. 14675 + --with-tune, which specifies the default value of the -mtune 14676 option. 14677 * Support for the z990 processor has been added, and can be selected 14678 using -march=z990 or -mtune=z990. This includes instruction 14679 scheduling tuned for the superscalar instruction pipeline of the 14680 z990 processor as well as support for all new instructions provided 14681 by the long-displacement facility. 14682 * Support to generate 31-bit code optimized for zSeries processors 14683 (running in ESA/390 or in z/Architecture mode) has been added. This 14684 can be selected using -march=z900 and -mzarch respectively. 14685 * Instruction scheduling for the z900 and z990 processors now uses 14686 the DFA pipeline hazard recognizer. 14687 * GCC no longer generates code to maintain a stack backchain, 14688 previously used to generate stack backtraces for debugging 14689 purposes. As replacement that does not incur runtime overhead, 14690 DWARF-2 call frame information is provided by GCC; this is 14691 supported by GDB 6.1. The old behavior can be restored using the 14692 -mbackchain option. 14693 * The stack frame size of functions may now exceed 2 GB in 64-bit 14694 code. 14695 * A port for the 64-bit IBM TPF operating system has been added; the 14696 configuration is s390x-ibm-tpf. This configuration is supported as 14697 cross-compilation target only. 14698 * Various changes to improve the generated code have been 14699 implemented, including: 14700 + GCC now uses the MULTIPLY AND ADD and MULTIPLY AND SUBTRACT 14701 instructions to significantly speed up many floating-point 14702 applications. 14703 + GCC now uses the ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL 14704 WITH BORROW instructions to speed up long long arithmetic. 14705 + GCC now uses the SEARCH STRING instruction to implement 14706 strlen(). 14707 + In many cases, function call overhead for 31-bit code has been 14708 reduced by placing the literal pool after the function code 14709 instead of after the function prolog. 14710 + Register 14 is no longer reserved in 64-bit code. 14711 + Handling of global register variables has been improved. 14712 14713 SPARC 14714 14715 * The option -mflat is deprecated. 14716 * Support for large (> 2GB) frames has been added to the 64-bit port. 14717 * Several [25]ABI bugs have been fixed. Unfortunately, these changes 14718 will break binary compatibility with earlier releases. 14719 * The default debugging format has been switched from STABS to 14720 DWARF-2 for 32-bit code on Solaris 7 and later. DWARF-2 is already 14721 the default debugging format for 64-bit code on Solaris. 14722 14723 SuperH 14724 14725 * Support for the SH2E processor has been added. Enabled at run time 14726 with the -m2e command line switch, or at configure time by 14727 specifying sh2e as the machine part of the target triple. 14728 14729 V850 14730 14731 * Support for the Mitsubishi V850E1 processor has been added. This is 14732 a variant of the V850E processor with some additional debugging 14733 instructions. 14734 14735 Xtensa 14736 14737 * Several ABI bugs have been fixed. Unfortunately, these changes 14738 break binary compatibility with earlier releases. 14739 + For big-endian processors, the padding of aggregate return 14740 values larger than a word has changed. If the size of an 14741 aggregate return value is not a multiple of 32 bits, previous 14742 versions of GCC inserted padding in the most-significant bytes 14743 of the first return value register. Aggregates larger than a 14744 word are now padded in the least-significant bytes of the last 14745 return value register used. Aggregates smaller than a word are 14746 still padded in the most-significant bytes. The return value 14747 padding has not changed for little-endian processors. 14748 + Function arguments with 16-byte alignment are now properly 14749 aligned. 14750 + The implementation of the va_list type has changed. A va_list 14751 value created by va_start from a previous release cannot be 14752 used with va_arg from this release, or vice versa. 14753 * More processor configuration options for Xtensa processors are 14754 supported: 14755 + the ABS instruction is now optional; 14756 + the ADDX* and SUBX* instructions are now optional; 14757 + an experimental CONST16 instruction can be used to synthesize 14758 constants instead of loading them from constant pools. 14759 These and other Xtensa processor configuration options can no 14760 longer be enabled or disabled by command-line options; the 14761 processor configuration must be specified by the xtensa-config.h 14762 header file when building GCC. Additionally, the 14763 -mno-serialize-volatile option is no longer supported. 14764 14765 Obsolete Systems 14766 14767 Support for a number of older systems has been declared obsolete in GCC 14768 3.4. Unless there is activity to revive them, the next release of GCC 14769 will have their sources permanently removed. 14770 14771 All configurations of the following processor architectures have been 14772 declared obsolete: 14773 * Mitsubishi D30V, d30v-* 14774 * AT&T DSP1600 and DSP1610, dsp16xx-* 14775 * Intel 80960, i960 14776 14777 Also, some individual systems have been obsoleted: 14778 * ARM Family 14779 + Support for generating code for operation in APCS/26 mode 14780 (-mapcs-26). 14781 * IBM ESA/390 14782 + "Bigfoot" port, i370-*. (The other port, s390-*, is actively 14783 maintained and supported.) 14784 * Intel 386 family 14785 + MOSS, i?86-moss-msdos and i?86-*-moss* 14786 + NCR 3000 running System V r.4, i?86-ncr-sysv4* 14787 + FreeBSD with a.out object format, i?86-*-freebsd*aout* and 14788 i?86-*-freebsd2* 14789 + GNU/Linux with a.out object format, i?86-linux*aout* 14790 + GNU/Linux with libc5, a.k.a. glibc1, i?86-linux*libc1* 14791 + Interix versions before Interix 3, i?86-*-interix 14792 + Mach microkernel, i?86-mach* 14793 + SCO UnixWare with UDK, i?86-*-udk* 14794 + Generic System V releases 1, 2, and 3, i?86-*-sysv[123]* 14795 + VSTa microkernel, i386-*-vsta 14796 * Motorola M68000 family 14797 + HPUX, m68k-hp-hpux* and m68000-hp-hpux* 14798 + NetBSD with a.out object format (before NetBSD 1.4), 14799 m68k-*-*-netbsd* except m68k-*-*-netbsdelf* 14800 + Generic System V r.4, m68k-*-sysv4* 14801 * VAX 14802 + Generic VAX, vax-*-* (This is generic VAX only; we have not 14803 obsoleted any VAX triples for specific operating systems.) 14804 14805 Documentation improvements 14806 14807 Other significant improvements 14808 14809 * The build system has undergone several significant cleanups. 14810 Subdirectories will only be configured if they are being built, and 14811 all subdirectory configures are run from the make command. The top 14812 level has been autoconfiscated. 14813 * Building GCC no longer writes to its source directory. This should 14814 help those wishing to share a read-only source directory over NFS 14815 or build from a CD. The exceptions to this feature are if you 14816 configure with either --enable-maintainer-mode or 14817 --enable-generated-files-in-srcdir. 14818 * The -W warning option has been renamed to -Wextra, which is more 14819 easily understood. The older spelling will be retained for 14820 backwards compatibility. 14821 * Substantial improvements in compile time have been made, 14822 particularly for non-optimizing compilations. 14823 __________________________________________________________________ 14824 14825 GCC 3.4.0 14826 14827 Bug Fixes 14828 14829 A vast number of bugs have been fixed in 3.4.0, too many to publish a 14830 complete list here. [26]Follow this link to query the Bugzilla database 14831 for the list of over 900 bugs fixed in 3.4.0. This is the list of all 14832 bugs marked as resolved and fixed in 3.4.0 that are not flagged as 3.4 14833 regressions. 14834 __________________________________________________________________ 14835 14836 GCC 3.4.1 14837 14838 Bug Fixes 14839 14840 This section lists the problem reports (PRs) from GCC's bug tracking 14841 system that are known to be fixed in the 3.4.1 release. This list might 14842 not be complete (that is, it is possible that some PRs that have been 14843 fixed are not listed here). 14844 14845 Bootstrap failures 14846 14847 * [27]10129 Ada bootstrap fails on PPC-Darwin - invalid assembler 14848 emitted - PIC related 14849 * [28]14576 [ARM] ICE in libiberty when building gcc-3.4 for arm-elf 14850 * [29]14760 A bug in configure.in prevents using both 14851 --program-suffix and --program-prefix 14852 * [30]14671 [hppa64] bootstrap fails: ICE in 14853 save_call_clobbered_regs, in caller_save.c 14854 * [31]15093 [alpha][Java] make bootstrap fails to configure libffi on 14855 Alpha 14856 * [32]15178 Solaris 9/x86 fails linking after stage 3 14857 14858 Multi-platform internal compiler errors (ICEs) 14859 14860 * [33]12753 (preprocessor) Memory corruption in preprocessor on bad 14861 input 14862 * [34]13985 ICE in gcc.c-torture/compile/930621-1.c 14863 * [35]14810 (c++) tree check failures with invalid code involving 14864 templates 14865 * [36]14883 (c++) ICE on invalid code, in cp_parser_lookup_name, in 14866 cp/parser.c 14867 * [37]15044 (c++) ICE on syntax error, template header 14868 * [38]15057 (c++) Compiling of conditional value throw constructs 14869 cause a segmentation violation 14870 * [39]15064 (c++) typeid of template parameter gives ICE 14871 * [40]15142 (c++) ICE when passing a string where a char* is expected 14872 in a throw statement 14873 * [41]15159 ICE in rtl_verify_flow_info_1 14874 * [42]15165 (c++) ICE in instantiate_template 14875 * [43]15193 Unary minus using pointer to V4SF vector causes 14876 -fforce-mem to exhaust all memory 14877 * [44]15209 (c++) Runs out of memory with packed structs 14878 * [45]15227 (c++) Trouble with invalid function definition 14879 * [46]15285 (c++) instantiate_type ICE when forming pointer to 14880 template function 14881 * [47]15299 (c++) ICE in resolve_overloaded_unification 14882 * [48]15329 (c++) ICE on constructor of member template 14883 * [49]15550 ICE in extract_insn, in recog.c 14884 * [50]15554 (c++) ICE in tsubst_copy, in cp/pt.c 14885 * [51]15640 (c++) ICE on invalid code in arg_assoc, in 14886 cp/name-lookup.c 14887 * [52]15666 [unit-at-a-time] Gcc abort on valid code 14888 * [53]15696 (c++) ICE with bad pointer-to-member code 14889 * [54]15701 (c++) ICE with friends and template template parameter 14890 * [55]15761 ICE in do_SUBST, in combine.c 14891 * [56]15829 (c++) ICE on Botan-1.3.13 due to -funroll-loops 14892 14893 Ada 14894 14895 * [57]14538 All RTEMS targets broken for gnat 14896 14897 C front end 14898 14899 * [58]12391 missing warning about assigning to an incomplete type 14900 * [59]14649 atan(1.0) should not be a constant expression 14901 * [60]15004 [unit-at-a-time] no warning for unused paramater in 14902 static function 14903 * [61]15749 --pedantic-errors behaves differently from --pedantic 14904 with C-compiler on GNU/Linux 14905 14906 C++ compiler and library 14907 14908 * [62]10646 non-const reference is incorrectly matched in a "const T" 14909 partial specialization 14910 * [63]12077 wcin.rdbuf()->in_avail() return value too high 14911 * [64]13598 enc_filebuf doesn't work 14912 * [65]14211 const_cast returns lvalue but should be rvalue 14913 * [66]14220 num_put::do_put() undesired float/double behavior 14914 * [67]14245 problem with user-defined allocators in std::basic_string 14915 * [68]14340 libstdc++ Debug mode: failure to convert iterator to 14916 const_iterator 14917 * [69]14600 __gnu_cxx::stdio_sync_filebuf should expose internal 14918 FILE* 14919 * [70]14668 no warning anymore for reevaluation of declaration 14920 * [71]14775 LFS (large file support) tests missing 14921 * [72]14821 Duplicate namespace alias declaration should not conflict 14922 * [73]14930 Friend declaration ignored 14923 * [74]14932 cannot use offsetof to get offsets of array elements in 14924 g++ 3.4.0 14925 * [75]14950 [non unit-at-a-time] always_inline does not mix with 14926 templates and -O0 14927 * [76]14962 g++ ignores #pragma redefine_extname 14928 * [77]14975 Segfault on low-level write error during imbue 14929 * [78]15002 Linewise stream input is unusably slow (std::string slow) 14930 * [79]15025 compiler accepts redeclaration of template as 14931 non-template 14932 * [80]15046 [arm] Math functions misdetected by cross configuration 14933 * [81]15069 a bit test on a variable of enum type is miscompiled 14934 * [82]15074 g++ -lsupc++ still links against libstdc++ 14935 * [83]15083 spurious "statement has no effect" warning 14936 * [84]15096 parse error with templates and pointer to const member 14937 * [85]15287 combination of operator[] and operator .* fails in 14938 templates 14939 * [86]15317 __attribute__ unused in first parameter of constructor 14940 gives error 14941 * [87]15337 sizeof on incomplete type diagnostic 14942 * [88]15361 bitset<>::_Find_next fails 14943 * [89]15412 _GLIBCXX_ symbols symbols defined and used in different 14944 namespaces 14945 * [90]15427 valid code results in incomplete type error 14946 * [91]15471 Incorrect member pointer offsets in anonymous 14947 structs/unions 14948 * [92]15503 nested template problem 14949 * [93]15507 compiler hangs while laying out union 14950 * [94]15542 operator & and template definitions 14951 * [95]15565 SLES9: leading + sign for unsigned int with showpos 14952 * [96]15625 friend defined inside a template fails to find static 14953 function 14954 * [97]15629 Function templates, overloads, and friend name injection 14955 * [98]15742 'noreturn' attribute ignored in method of template 14956 functions. 14957 * [99]15775 Allocator::pointer consistently ignored 14958 * [100]15821 Duplicate namespace alias within namespace rejected 14959 * [101]15862 'enum yn' fails (confict with undeclared builtin) 14960 * [102]15875 rejects pointer to member in template 14961 * [103]15877 valid code using templates and anonymous enums is 14962 rejected 14963 * [104]15947 Puzzling error message for wrong destructor declaration 14964 in template class 14965 * [105]16020 cannot copy __gnu_debug::bitset 14966 * [106]16154 input iterator concept too restrictive 14967 * [107]16174 deducing top-level consts 14968 14969 Java 14970 14971 * [108]14315 Java compiler is not parallel make safe 14972 14973 Fortran 14974 14975 * [109]15151 [g77] incorrect logical i/o in 64-bit mode 14976 14977 Objective-C 14978 14979 * [110]7993 private variables cannot be shadowed in subclasses 14980 14981 Optimization bugs 14982 14983 * [111]15228 useless copies of floating point operands 14984 * [112]15345 [non-unit-at-a-time] unreferenced nested inline 14985 functions not optimized away 14986 * [113]15945 Incorrect floating point optimization 14987 * [114]15526 ftrapv aborts on 0 * (-1) 14988 * [115]14690 Miscompiled POOMA tests 14989 * [116]15112 GCC generates code to write to unchanging memory 14990 14991 Preprocessor 14992 14993 * [117]15067 Minor glitch in the source of cpp 14994 14995 Main driver program bugs 14996 14997 * [118]1963 collect2 interprets -oldstyle_liblookup as -o 14998 ldstyle_liblookup 14999 15000 x86-specific (Intel/AMD) 15001 15002 * [119]15717 Error: can't resolve `L0' {*ABS* section} - `xx' {*UND* 15003 section} 15004 15005 HPPA-specific 15006 15007 * [120]14782 GCC produces an unaligned data access at -O2 15008 * [121]14828 FAIL: gcc.c-torture/execute/20030408-1.c execution, -O2 15009 * [122]15202 ICE in reload_cse_simplify_operands, in postreload.c 15010 15011 IA64-specific 15012 15013 * [123]14610 __float80 constants incorrectly emitted 15014 * [124]14813 init_array sections are initialized in the wrong order 15015 * [125]14857 GCC segfault on duplicated asm statement 15016 * [126]15598 Gcc 3.4 ICE on valid code 15017 * [127]15653 Gcc 3.4 ICE on valid code 15018 15019 MIPS-specific 15020 15021 * [128]15189 wrong filling of delay slot with -march=mips1 -G0 15022 -mno-split-addresses -mno-explicit-relocs 15023 * [129]15331 Assembler error building gnatlib on IRIX 6.5 with GNU as 15024 2.14.91 15025 * [130]16144 Bogus reference to __divdf3 when -O1 15026 * [131]16176 Miscompilation of unaligned data in MIPS backend 15027 15028 PowerPC-specific 15029 15030 * [132]11591 ICE in gcc.dg/altivec-5.c 15031 * [133]12028 powerpc-eabispe produces bad sCOND operation 15032 * [134]14478 rs6000 geu/ltu patterns generate incorrect code 15033 * [135]14567 long double and va_arg complex args 15034 * [136]14715 Altivec stack layout may overlap gpr save with stack 15035 temps 15036 * [137]14902 (libstdc++) Stream checking functions fail when -pthread 15037 option is used. 15038 * [138]14924 Compiler ICE on valid code 15039 * [139]14960 -maltivec affects vector return with -mabi=no-altivec 15040 * [140]15106 vector varargs failure passing from altivec to 15041 non-altivec code for -m32 15042 * [141]16026 ICE in function.c:4804, assign_parms, when -mpowerpc64 & 15043 half-word operation 15044 * [142]15191 -maltivec -mabi=no-altivec results in mis-aligned lvx 15045 and stvx 15046 * [143]15662 Segmentation fault when an exception is thrown - even if 15047 try and catch are specified 15048 15049 s390-specific 15050 15051 * [144]15054 Bad code due to overlapping stack temporaries 15052 15053 SPARC-specific 15054 15055 * [145]15783 ICE with union assignment in 64-bit mode 15056 * [146]15626 GCC 3.4 emits "ld: warning: relocation error: 15057 R_SPARC_UA32" 15058 15059 x86-64-specific 15060 15061 * [147]14326 boehm-gc hardcodes to 3DNow! prefetch for x86_64 15062 * [148]14723 Backported -march=nocona from mainline 15063 * [149]15290 __float128 failed to pass to function properly 15064 15065 Cygwin/Mingw32-specific 15066 15067 * [150]15250 Option -mms-bitfields support on GCC 3.4 is not 15068 conformant to MS layout 15069 * [151]15551 -mtune=pentium4 -O2 with sjlj EH breaks stack probe 15070 worker on windows32 targets 15071 15072 Bugs specific to embedded processors 15073 15074 * [152]8309 [m68k] -m5200 produces erroneous SImode set of short 15075 varaible on stack 15076 * [153]13250 [SH] Gcc code for rotation clobbers the register, but 15077 gcc continues to use the register as if it was not clobbered 15078 * [154]13803 [coldfire] movqi operand constraints too restrictivefor 15079 TARGET_COLDFIRE 15080 * [155]14093 [SH] ICE for code when using -mhitachi option in SH 15081 * [156]14457 [m6811hc] ICE with simple c++ source 15082 * [157]14542 [m6811hc] ICE on simple source 15083 * [158]15100 [SH] cc1plus got hang-up on 15084 libstdc++-v3/testsuite/abi_check.cc 15085 * [159]15296 [CRIS] Delayed branch scheduling causing invalid code on 15086 cris-* 15087 * [160]15396 [SH] ICE with -O2 -fPIC 15088 * [161]15782 [coldfire] m68k_output_mi_thunk emits wrong code for 15089 ColdFire 15090 15091 Testsuite problems (compiler not affected) 15092 15093 * [162]11610 libstdc++ testcases 27_io/* don't work properly remotely 15094 * [163]15488 (libstdc++) possibly insufficient file permissions for 15095 executing test suite 15096 * [164]15489 (libstdc++) testsuite_files determined incorrectly 15097 15098 Documentation bugs 15099 15100 * [165]13928 (libstdc++) no whatis info in some man pages generated 15101 by doxygen 15102 * [166]14150 Ada documentation out of date 15103 * [167]14949 (c++) Need to document method visibility changes 15104 * [168]15123 libstdc++-doc: Allocators.3 manpage is empty 15105 __________________________________________________________________ 15106 15107 GCC 3.4.2 15108 15109 Bug Fixes 15110 15111 This section lists the problem reports (PRs) from GCC's bug tracking 15112 system that are known to be fixed in the 3.4.2 release. This list might 15113 not be complete (that is, it is possible that some PRs that have been 15114 fixed are not listed here). 15115 15116 Bootstrap failures and issues 15117 15118 * [169]16469 [mips-sgi-irix5.3] bootstrap fails in 15119 libstdc++-v3/testsuite 15120 * [170]16344 [hppa-linux-gnu] libstdc++'s PCH built by 15121 profiledbootstrap does not work with the built compiler 15122 * [171]16842 [Solaris/x86] mkheaders can not find mkheaders.conf 15123 15124 Multi-platform internal compiler errors (ICEs) 15125 15126 * [172]12608 (c++) ICE: expected class 't', have 'x' (error_mark) in 15127 cp_parser_class_specifier, in cp/parser.c 15128 * [173]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 15129 * [174]15461 (c++) ICE due to NRV and inlining 15130 * [175]15890 (c++) ICE in c_expand_expr, in c-common.c 15131 * [176]16180 ICE: segmentation fault in RTL optimization 15132 * [177]16224 (c++) ICE in write_unscoped_name (template/namespace) 15133 * [178]16408 ICE: in delete_insn, in cfgrtl.c 15134 * [179]16529 (c++) ICE for: namespace-alias shall not be declared as 15135 the name of any other entity 15136 * [180]16698 (c++) ICE with exceptions and declaration of __cxa_throw 15137 * [181]16706 (c++) ICE in finish_member_declaration, in 15138 cp/semantics.c 15139 * [182]16810 (c++) Legal C++ program with cast gives ICE in 15140 build_ptrmemfunc 15141 * [183]16851 (c++) ICE when throwing a comma expression 15142 * [184]16870 (c++) Boost.Spirit causes ICE in tsubst, in cp/pt.c 15143 * [185]16904 (c++) ICE in finish_class_member_access_expr, in 15144 cp/typeck.c 15145 * [186]16905 (c++) ICE (segfault) with exceptions 15146 * [187]16964 (c++) ICE in cp_parser_class_specifier due to 15147 redefinition 15148 * [188]17068 (c++) ICE: tree check: expected class 'd', have 'x' 15149 (identifier_node) in dependent_template_p, in cp/pt.c 15150 15151 Preprocessor bugs 15152 15153 * [189]16366 Preprocessor option -remap causes memory corruption 15154 15155 Optimization 15156 15157 * [190]15345 unreferenced nested inline functions not optimized away 15158 * [191]16590 Incorrect execution when compiling with -O2 15159 * [192]16693 Bitwise AND is lost when used within a cast to an enum 15160 of the same precision 15161 * [193]17078 Jump into if(0) substatement fails 15162 15163 Problems in generated debug information 15164 15165 * [194]13956 incorrect stabs for nested local variables 15166 15167 C front end bugs 15168 15169 * [195]16684 GCC should not warn about redundant redeclarations of 15170 built-ins 15171 15172 C++ compiler and library 15173 15174 * [196]12658 Thread safety problems in locale::global() and 15175 locale::locale() 15176 * [197]13092 g++ accepts invalid pointer-to-member conversion 15177 * [198]15320 Excessive memory consumption 15178 * [199]16246 Incorrect template argument deduction 15179 * [200]16273 Memory exhausted when using nested classes and virtual 15180 functions 15181 * [201]16401 ostringstream in gcc 3.4.x very slow for big data 15182 * [202]16411 undefined reference to 15183 __gnu_cxx::stdio_sync_filebuf<char, std::char_traits<char> 15184 >::file() 15185 * [203]16489 G++ incorrectly rejects use of a null constant integral 15186 expression as a null constant pointer 15187 * [204]16618 offsetof fails with constant member 15188 * [205]16637 syntax error reported for valid input code 15189 * [206]16717 __attribute__((constructor)) broken in C++ 15190 * [207]16813 compiler error in DEBUG version of range insertion 15191 std::map::insert 15192 * [208]16853 pointer-to-member initialization from incompatible one 15193 accepted 15194 * [209]16889 ambiguity is not detected 15195 * [210]16959 Segmentation fault in ios_base::sync_with_stdio 15196 15197 Java compiler and library 15198 15199 * [211]7587 direct threaded interpreter not thread-safe 15200 * [212]16473 ServerSocket accept() leaks file descriptors 15201 * [213]16478 Hash synchronization deadlock with finalizers 15202 15203 Alpha-specific 15204 15205 * [214]10695 ICE in dwarf2out_frame_debug_expr, in dwarf2out.c 15206 * [215]16974 could not split insn (ice in final_scan_insn, in 15207 final.c) 15208 15209 x86-specific 15210 15211 * [216]16298 ICE in output_operand 15212 * [217]17113 ICE with SSE2 intrinsics 15213 15214 x86-64 specific 15215 15216 * [218]14697 libstdc++ couldn't find 32bit libgcc_s 15217 15218 MIPS-specific 15219 15220 * [219]15869 [mips64] No NOP after LW (with -mips1 -O0) 15221 * [220]16325 [mips64] value profiling clobbers gp on mips 15222 * [221]16357 [mipsisa64-elf] ICE copying 7 bytes between extern 15223 char[]s 15224 * [222]16380 [mips64] Use of uninitialised register after dbra 15225 conversion 15226 * [223]16407 [mips64] Unaligned access to local variables 15227 * [224]16643 [mips64] verify_local_live_at_start ICE after 15228 crossjumping & cfgcleanup 15229 15230 ARM-specific 15231 15232 * [225]15927 THUMB -O2: strength-reduced iteration variable ends up 15233 off by 1 15234 * [226]15948 THUMB: ICE with non-commutative cbranch 15235 * [227]17019 THUMB: bad switch statement in md code for 15236 addsi3_cbranch_scratch 15237 15238 IA64-specific 15239 15240 * [228]16130 ICE on valid code: in bundling, in config/ia64/ia64.c 15241 (-mtune=merced) 15242 * [229]16142 ICE on valid code: in bundling, in config/ia64/ia64.c 15243 (-mtune=itanium) 15244 * [230]16278 Gcc failed to build Linux kernel with -mtune=merced 15245 * [231]16414 ICE on valid code: typo in comparison of asm_noperands 15246 result 15247 * [232]16445 ICE on valid code: don't count ignored insns 15248 * [233]16490 ICE (segfault) while compiling with -fprofile-use 15249 * [234]16683 ia64 does not honor SUBTARGET_EXTRA_SPECS 15250 15251 PowerPC-specific 15252 15253 * [235]16195 (ppc64): Miscompilation of GCC 3.3.x by 3.4.x 15254 * [236]16239 ICE on ppc64 (mozilla 1.7 compile, -O1 -fno-exceptions 15255 issue) 15256 15257 SPARC-specific 15258 15259 * [237]16199 ICE while compiling apache 2.0.49 15260 * [238]16416 -m64 doesn't imply -mcpu=v9 anymore 15261 * [239]16430 ICE when returning non-C aggregates larger than 16 bytes 15262 15263 Bugs specific to embedded processors 15264 15265 * [240]16379 [m32r] can't output large model function call of memcpy 15266 * [241]17093 [m32r] ICE with -msdata=use -O0 15267 * [242]17119 [m32r] ICE at switch case 0x8000 15268 15269 DJGPP-specific 15270 15271 * [243]15928 libstdc++ in 3.4.x doesn't cross-compile for djgpp 15272 15273 Alpha Tru64-specific 15274 15275 * [244]16210 libstdc++ gratuitously omits "long long" I/O 15276 15277 Testsuite, documentation issues (compiler is not affected): 15278 15279 * [245]15488 (libstdc++) possibly insufficient file permissions for 15280 executing test suite 15281 * [246]16250 ada/doctools runs makeinfo even in release tarball 15282 __________________________________________________________________ 15283 15284 GCC 3.4.3 15285 15286 This is the [247]list of problem reports (PRs) from GCC's bug tracking 15287 system that are known to be fixed in the 3.4.3 release. This list might 15288 not be complete (that is, it is possible that some PRs that have been 15289 fixed are not listed here). 15290 15291 Bootstrap failures 15292 15293 * [248]17369 [ia64] Bootstrap failure with binutils-2.15.90.0.1.1 15294 * [249]17850 [arm-elf] bootstrap failure - libstdc++ uses strtold 15295 when undeclared 15296 15297 Internal compiler errors (ICEs) affecting multiple platforms 15298 15299 * [250]13948 (java) GCJ segmentation fault while compiling GL4Java 15300 .class files 15301 * [251]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c 15302 * [252]16301 (c++) ICE when "strong" attribute is attached to a using 15303 directive 15304 * [253]16566 ICE with flexible arrays 15305 * [254]17023 ICE with nested functions in parameter declaration 15306 * [255]17027 ICE with noreturn function in loop at -O2 15307 * [256]17524 ICE in grokdeclarator, in cp/decl.c 15308 * [257]17826 (c++) ICE in cp_tree_equal 15309 15310 C and optimization bugs 15311 15312 * [258]15526 -ftrapv aborts on 0 * (-1) 15313 * [259]16999 #ident stopped working 15314 * [260]17503 quadratic behaviour in invalid_mode_change_p 15315 * [261]17581 Long long arithmetic fails inside a switch/case 15316 statement when compiled with -O2 15317 * [262]18129 -fwritable-strings doesn't work 15318 15319 C++ compiler and library bugs 15320 15321 * [263]10975 incorrect initial ostringstream::tellp() 15322 * [264]11722 Unbuffered filebuf::sgetn is slow 15323 * [265]14534 Unrecognizing static function as a template parameter 15324 when its return value is also templated 15325 * [266]15172 Copy constructor optimization in aggregate 15326 initialization 15327 * [267]15786 Bad error message for frequently occuring error. 15328 * [268]16162 Rejects valid member-template-definition 15329 * [269]16612 empty basic_strings can't live in shared memory 15330 * [270]16715 std::basic_iostream is instantiated when used, even 15331 though instantiations are already contained in libstdc++ 15332 * [271]16848 code in /ext/demangle.h appears broken 15333 * [272]17132 GCC fails to eliminate function template specialization 15334 when argument deduction fails 15335 * [273]17259 One more _S_leaf incorrectly qualified with _RopeRep:: 15336 in ropeimpl.h 15337 * [274]17327 use of `enumeral_type' in template type unification 15338 * [275]17393 "unused variable '._0'" warning with -Wall 15339 * [276]17501 Confusion with member templates 15340 * [277]17537 g++ not passing -lstdc++ to linker when all command line 15341 arguments are libraries 15342 * [278]17585 usage of unqualified name of static member from within 15343 class not allowed 15344 * [279]17821 Poor diagnostic for using "." instead of "->" 15345 * [280]17829 wrong error: call of overloaded function is ambiguous 15346 * [281]17851 Misleading diagnostic for invalid function declarations 15347 with undeclared types 15348 * [282]17976 Destructor is called twice 15349 * [283]18020 rejects valid definition of enum value in template 15350 * [284]18093 bogus conflict in namespace aliasing 15351 * [285]18140 C++ parser bug when using >> in templates 15352 15353 Fortran 15354 15355 * [286]17541 data statements with double precision constants fail 15356 15357 x86-specific 15358 15359 * [287]17853 -O2 ICE for MMX testcase 15360 15361 SPARC-specific 15362 15363 * [288]17245 ICE compiling gsl-1.5 statistics/lag1.c 15364 15365 Darwin-specific 15366 15367 * [289]17167 FATAL:Symbol L_foo$stub already defined. 15368 15369 AIX-specific 15370 15371 * [290]17277 could not catch an exception when specified -maix64 15372 15373 Solaris-specific 15374 15375 * [291]17505 <cmath> calls acosf(), ceilf(), and other functions 15376 missing from system libraries 15377 15378 HP/UX specific: 15379 15380 * [292]17684 /usr/ccs/bin/ld: Can't create libgcc_s.sl 15381 15382 ARM-specific 15383 15384 * [293]17384 ICE with mode attribute on structures 15385 15386 MIPS-specific 15387 15388 * [294]17770 No NOP after LWL with -mips1 15389 15390 Other embedded target specific 15391 15392 * [295]11476 [arc-elf] gcc ICE on newlib's vfprintf.c 15393 * [296]14064 [avr-elf] -fdata-sections triggers ICE 15394 * [297]14678 [m68hc11-elf] gcc ICE 15395 * [298]15583 [powerpc-rtems] powerpc-rtems lacks __USE_INIT_FINI__ 15396 * [299]15790 [i686-coff] Alignment error building gcc with i686-coff 15397 target 15398 * [300]15886 [SH] Miscompilation with -O2 -fPIC 15399 * [301]16884 [avr-elf] [fweb related] bug while initializing 15400 variables 15401 15402 Bugs relating to debugger support 15403 15404 * [302]13841 missing debug info for _Complex function arguments 15405 * [303]15860 [big-endian targets] No DW_AT_location debug info is 15406 emitted for formal arguments to a function that uses "register" 15407 qualifiers 15408 15409 Testsuite issues (compiler not affected) 15410 15411 * [304]17465 Testsuite in libffi overrides LD_LIBRARY_PATH 15412 * [305]17469 Testsuite in libstdc++ overrides LD_LIBRARY_PATH 15413 * [306]18138 [mips-sgi-irix6.5] libgcc_s.so.1 not found by 64-bit 15414 testsuite 15415 15416 Documentation 15417 15418 * [307]15498 typo in gcc manual: non-existing locale example en_UK, 15419 should be en_GB 15420 * [308]15747 [mips-sgi-irix5.3] /bin/sh hangs during bootstrap: 15421 document broken shell 15422 * [309]16406 USE_LD_AS_NEEDED undocumented 15423 __________________________________________________________________ 15424 15425 GCC 3.4.4 15426 15427 This is the [310]list of problem reports (PRs) from GCC's bug tracking 15428 system that are known to be fixed in the 3.4.4 release. This list might 15429 not be complete (that is, it is possible that some PRs that have been 15430 fixed are not listed here). 15431 __________________________________________________________________ 15432 15433 GCC 3.4.5 15434 15435 This is the [311]list of problem reports (PRs) from GCC's bug tracking 15436 system that are known to be fixed in the 3.4.5 release. This list might 15437 not be complete (that is, it is possible that some PRs that have been 15438 fixed are not listed here). 15439 15440 Bootstrap issues 15441 15442 * [312]24688 sco_math fixincl breaks math.h 15443 15444 C compiler bugs 15445 15446 * [313]17188 struct Foo { } redefinition 15447 * [314]20187 wrong code for ((unsigned char)(unsigned long 15448 long)((a?a:1)&(a*b)))?0:1) 15449 * [315]21873 infinite warning loop on bad array initializer 15450 * [316]21899 enum definition accepts values to be overriden 15451 * [317]22061 ICE in find_function_data, in function.c 15452 * [318]22308 Failure to diagnose violation of constraint 6.516p2 15453 * [319]22458 ICE on missing brace 15454 * [320]22589 ICE casting to long long 15455 * [321]24101 Segfault with preprocessed source 15456 15457 C++ compiler and library bugs 15458 15459 * [322]10611 operations on vector mode not recognized in C++ 15460 * [323]13377 unexpected behavior of namespace usage directive 15461 * [324]16002 Strange error message with new parser 15462 * [325]17413 local classes as template argument 15463 * [326]17609 spurious error message after using keyword 15464 * [327]17618 ICE in cp_convert_to_pointer, in cp/cvt.c 15465 * [328]18124 ICE with invalid template template parameter 15466 * [329]18155 typedef in template declaration not rejected 15467 * [330]18177 ICE with const_cast for undeclared variable 15468 * [331]18368 C++ error message regression 15469 * [332]16378 ICE when returning a copy of a packed member 15470 * [333]18466 int ::i; accepted 15471 * [334]18512 ICE on invalid usage of template base class 15472 * [335]18454 ICE when returning undefined type 15473 * [336]18738 typename not allowed with non-dependent qualified name 15474 * [337]18803 rejects access to operator() in template 15475 * [338]19004 ICE in uses_template_parms, in cp/pt.c 15476 * [339]19208 Spurious error about variably modified type 15477 * [340]18253 bad error message / ICE for invalid template parameter 15478 * [341]19608 ICE after friend function definition in local class 15479 * [342]19884 ICE on explicit instantiation of a non-template 15480 constructor 15481 * [343]20153 ICE when C++ template function contains anonymous union 15482 * [344]20563 Infinite loop in diagnostic (and ice after error 15483 message) 15484 * [345]20789 ICE with incomplete type in template 15485 * [346]21336 Internal compiler error when using custom new operators 15486 * [347]21768 ICE in error message due to violation of coding 15487 conventions 15488 * [348]21853 constness of pointer to data member ignored 15489 * [349]21903 Default argument of template function causes a 15490 compile-time error 15491 * [350]21983 multiple diagnostics 15492 * [351]21987 New testsuite failure 15493 g++.dg/warn/conversion-function-1.C 15494 * [352]22153 ICE on invalid template specialization 15495 * [353]22172 Internal compiler error, seg fault. 15496 * [354]21286 filebuf::xsgetn vs pipes 15497 * [355]22233 ICE with wrong number of template parameters 15498 * [356]22508 ICE after invalid operator new 15499 * [357]22545 ICE with pointer to class member & user defined 15500 conversion operator 15501 * [358]23528 Wrong default allocator in ext/hash_map 15502 * [359]23550 char_traits requirements/1.cc test bad math 15503 * [360]23586 Bad diagnostic for invalid namespace-name 15504 * [361]23624 ICE in invert_truthvalue, in fold-const.c 15505 * [362]23639 Bad error message: not a member of '<declaration error>' 15506 * [363]23797 ICE on typename outside template 15507 * [364]23965 Bogus error message: no matching function for call to 15508 'foo(<type error>)' 15509 * [365]24052 &#`label_decl' not supported by dump_expr#<expression 15510 error> 15511 * [366]24580 virtual base class cause exception not to be caught 15512 15513 Problems in generated debug information 15514 15515 * [367]24267 Bad DWARF for altivec vectors 15516 15517 Optimizations issues 15518 15519 * [368]17810 ICE in verify_local_live_at_start 15520 * [369]17860 Wrong generated code for loop with varying bound 15521 * [370]21709 ICE on compile-time complex NaN 15522 * [371]21964 broken tail call at -O2 or more 15523 * [372]22167 Strange optimization bug when using -Os 15524 * [373]22619 Compilation failure for real_const_1.f and 15525 real_const_2.f90 15526 * [374]23241 Invalid code generated for comparison of uchar to 255 15527 * [375]23478 Miscompilation due to reloading of a var that is also 15528 used in EH pad 15529 * [376]24470 segmentation fault in cc1plus when compiling with -O 15530 * [377]24950 ICE in operand_subword_force 15531 15532 Precompiled headers problems 15533 15534 * [378]14400 Cannot compile qt-x11-free-3.3.0 15535 * [379]14940 PCH largefile test fails on various platforms 15536 15537 Preprocessor bugs 15538 15539 * [380]20239 ICE on empty preprocessed input 15540 * [381]15220 "gcc -E -MM -MG" reports missing system headers in 15541 source directory 15542 15543 Testsuite issues 15544 15545 * [382]19275 gcc.dg/20020919-1.c fails with -fpic/-fPIC on 15546 i686-pc-linux-gnu 15547 15548 Alpha specific 15549 15550 * [383]21888 bootstrap failure with linker relaxation enabled 15551 15552 ARM specific 15553 15554 * [384]15342 [arm-linux]: ICE in verify_local_live_at_start 15555 * [385]23985 Memory aliasing information incorrect in inlined memcpy 15556 15557 ColdFile specific 15558 15559 * [386]16719 Illegal move of byte into address register causes 15560 compiler to ICE 15561 15562 HPPA specific 15563 15564 * [387]21723 ICE while building libgfortran 15565 * [388]21841 -mhp-ld/-mgnu-ld documentation 15566 15567 IA-64 specific 15568 15569 * [389]23644 IA-64 hardware models and configuration options 15570 documentation error 15571 * [390]24718 Shared libgcc not used for linking by default 15572 15573 M68000 specific 15574 15575 * [391]18421 ICE in reload_cse_simplify_operands, in postreload.c 15576 15577 MIPS specific 15578 15579 * [392]20621 ICE in change_address_1, in emit-rtl.c 15580 15581 PowerPC and PowerPC64 specific 15582 15583 * [393]18583 error on valid code: const 15584 __attribute__((altivec(vector__))) doesn't work in arrays 15585 * [394]20191 ICE in reload_cse_simplify_operands 15586 * [395]22083 AIX: TARGET_C99_FUNCTIONS is wrongly defined 15587 * [396]23070 CALL_V4_CLEAR_FP_ARGS flag not properly set 15588 * [397]23404 gij trashes args of functions with more than 8 fp args 15589 * [398]23539 C & C++ compiler generating misaligned references 15590 regardless of compiler flags 15591 * [399]24102 floatdisf2_internal2 broken 15592 * [400]24465 -mminimal-toc miscompilation of __thread vars 15593 15594 Solaris specific 15595 15596 * [401]19933 Problem with define of HUGE_VAL in math_c99 15597 * [402]21889 Native Solaris assembler cannot grok DTP-relative debug 15598 symbols 15599 15600 SPARC specific 15601 15602 * [403]19300 PCH failures on sparc-linux 15603 * [404]20301 Assembler labels have a leading "-" 15604 * [405]20673 C PCH testsuite assembly comparison failure 15605 15606 x86 and x86_64 specific 15607 15608 * [406]18582 ICE with arrays of type V2DF 15609 * [407]19340 Compilation SEGFAULTs with -O1 -fschedule-insns2 15610 -fsched2-use-traces 15611 * [408]21716 ICE in reg-stack.c's swap_rtx_condition 15612 * [409]24315 amd64 fails -fpeephole2 15613 __________________________________________________________________ 15614 15615 GCC 3.4.6 15616 15617 This is the [410]list of problem reports (PRs) from GCC's bug tracking 15618 system that are known to be fixed in the 3.4.6 release. This list might 15619 not be complete (that is, it is possible that some PRs that have been 15620 fixed are not listed here). 15621 15622 15623 For questions related to the use of GCC, please consult these web 15624 pages and the [411]GCC manuals. If that fails, the 15625 [412]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 15626 web pages and the development of GCC are welcome on our developer 15627 list at [413]gcc (a] gcc.gnu.org. All of [414]our lists have public 15628 archives. 15629 15630 Copyright (C) [415]Free Software Foundation, Inc. Verbatim copying and 15631 distribution of this entire article is permitted in any medium, 15632 provided this notice is preserved. 15633 15634 These pages are [416]maintained by the GCC team. 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330. https://gcc.gnu.org/PR18177 15969 331. https://gcc.gnu.org/PR18368 15970 332. https://gcc.gnu.org/PR18378 15971 333. https://gcc.gnu.org/PR18466 15972 334. https://gcc.gnu.org/PR18512 15973 335. https://gcc.gnu.org/PR18545 15974 336. https://gcc.gnu.org/PR18738 15975 337. https://gcc.gnu.org/PR18803 15976 338. https://gcc.gnu.org/PR19004 15977 339. https://gcc.gnu.org/PR19208 15978 340. https://gcc.gnu.org/PR19253 15979 341. https://gcc.gnu.org/PR19608 15980 342. https://gcc.gnu.org/PR19884 15981 343. https://gcc.gnu.org/PR20153 15982 344. https://gcc.gnu.org/PR20563 15983 345. https://gcc.gnu.org/PR20789 15984 346. https://gcc.gnu.org/PR21336 15985 347. https://gcc.gnu.org/PR21768 15986 348. https://gcc.gnu.org/PR21853 15987 349. https://gcc.gnu.org/PR21903 15988 350. https://gcc.gnu.org/PR21983 15989 351. https://gcc.gnu.org/PR21987 15990 352. https://gcc.gnu.org/PR22153 15991 353. https://gcc.gnu.org/PR22172 15992 354. https://gcc.gnu.org/PR21286 15993 355. 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https://gcc.gnu.org/PR20673 16044 406. https://gcc.gnu.org/PR18582 16045 407. https://gcc.gnu.org/PR19340 16046 408. https://gcc.gnu.org/PR21716 16047 409. https://gcc.gnu.org/PR24315 16048 410. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.6 16049 411. https://gcc.gnu.org/onlinedocs/ 16050 412. mailto:gcc-help (a] gcc.gnu.org 16051 413. mailto:gcc (a] gcc.gnu.org 16052 414. https://gcc.gnu.org/lists.html 16053 415. https://www.fsf.org/ 16054 416. https://gcc.gnu.org/about.html 16055 417. http://validator.w3.org/check/referer 16056 ====================================================================== 16057 http://gcc.gnu.org/gcc-3.3/index.html 16058 16059 GCC 3.3 Release Series 16060 16061 (This release series is no longer supported.) 16062 16063 May 03, 2005 16064 16065 The [1]GNU project and the GCC developers are pleased to announce the 16066 release of GCC 3.3.6. 16067 16068 This release is a bug-fix release, containing fixes for regressions in 16069 GCC 3.3.5 relative to previous releases of GCC. 16070 16071 This release is the last of the series 3.3.x. 16072 16073 The GCC 3.3 release series includes numerous [2]new features, 16074 improvements, bug fixes, and other changes, thanks to an [3]amazing 16075 group of volunteers. 16076 16077 Release History 16078 16079 GCC 3.3.6 16080 May 3, 2005 ([4]changes) 16081 16082 GCC 3.3.5 16083 September 30, 2004 ([5]changes) 16084 16085 GCC 3.3.4 16086 May 31, 2004 ([6]changes) 16087 16088 GCC 3.3.3 16089 February 14, 2004 ([7]changes) 16090 16091 GCC 3.3.2 16092 October 16, 2003 ([8]changes) 16093 16094 GCC 3.3.1 16095 August 8, 2003 ([9]changes) 16096 16097 GCC 3.3 16098 May 14, 2003 ([10]changes) 16099 16100 References and Acknowledgements 16101 16102 GCC used to stand for the GNU C Compiler, but since the compiler 16103 supports several other languages aside from C, it now stands for the 16104 GNU Compiler Collection. 16105 16106 A list of [11]successful builds is updated as new information becomes 16107 available. 16108 16109 The GCC developers would like to thank the numerous people that have 16110 contributed new features, improvements, bug fixes, and other changes as 16111 well as test results to GCC. This [12]amazing group of volunteers is 16112 what makes GCC successful. 16113 16114 For additional information about GCC please refer to the [13]GCC 16115 project web site or contact the [14]GCC development mailing list. 16116 16117 To obtain GCC please use [15]our mirror sites, or our CVS server. 16118 16119 16120 For questions related to the use of GCC, please consult these web 16121 pages and the [16]GCC manuals. If that fails, the 16122 [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 16123 web pages and the development of GCC are welcome on our developer 16124 list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public 16125 archives. 16126 16127 Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and 16128 distribution of this entire article is permitted in any medium, 16129 provided this notice is preserved. 16130 16131 These pages are [21]maintained by the GCC team. Last modified 16132 2019-11-28[22]. 16133 16134 References 16135 16136 1. http://www.gnu.org/ 16137 2. http://gcc.gnu.org/gcc-3.3/changes.html 16138 3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 16139 4. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 16140 5. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.5 16141 6. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.4 16142 7. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.3 16143 8. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.2 16144 9. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.1 16145 10. http://gcc.gnu.org/gcc-3.3/changes.html 16146 11. http://gcc.gnu.org/gcc-3.3/buildstat.html 16147 12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 16148 13. http://gcc.gnu.org/index.html 16149 14. mailto:gcc (a] gcc.gnu.org 16150 15. http://gcc.gnu.org/mirrors.html 16151 16. https://gcc.gnu.org/onlinedocs/ 16152 17. mailto:gcc-help (a] gcc.gnu.org 16153 18. mailto:gcc (a] gcc.gnu.org 16154 19. https://gcc.gnu.org/lists.html 16155 20. https://www.fsf.org/ 16156 21. https://gcc.gnu.org/about.html 16157 22. http://validator.w3.org/check/referer 16158 ====================================================================== 16159 http://gcc.gnu.org/gcc-3.3/changes.html 16160 16161 GCC 3.3 Release Series 16162 Changes, New Features, and Fixes 16163 16164 The latest release in the 3.3 release series is [1]GCC 3.3.6. 16165 16166 Caveats 16167 16168 * The preprocessor no longer accepts multi-line string literals. They 16169 were deprecated in 3.0, 3.1, and 3.2. 16170 * The preprocessor no longer supports the -A- switch when appearing 16171 alone. -A- followed by an assertion is still supported. 16172 * Support for all the systems [2]obsoleted in GCC 3.1 has been 16173 removed from GCC 3.3. See below for a [3]list of systems which are 16174 obsoleted in this release. 16175 * Checking for null format arguments has been decoupled from the rest 16176 of the format checking mechanism. Programs which use the format 16177 attribute may regain this functionality by using the new [4]nonnull 16178 function attribute. Note that all functions for which GCC has a 16179 built-in format attribute, an appropriate built-in nonnull 16180 attribute is also applied. 16181 * The DWARF (version 1) debugging format has been deprecated and will 16182 be removed in a future version of GCC. Version 2 of the DWARF 16183 debugging format will continue to be supported for the foreseeable 16184 future. 16185 * The C and Objective-C compilers no longer accept the "Naming Types" 16186 extension (typedef foo = bar); it was already unavailable in C++. 16187 Code which uses it will need to be changed to use the "typeof" 16188 extension instead: typedef typeof(bar) foo. (We have removed this 16189 extension without a period of deprecation because it has caused the 16190 compiler to crash since version 3.0 and no one noticed until very 16191 recently. Thus we conclude it is not in widespread use.) 16192 * The -traditional C compiler option has been removed. It was 16193 deprecated in 3.1 and 3.2. (Traditional preprocessing remains 16194 available.) The <varargs.h> header, used for writing variadic 16195 functions in traditional C, still exists but will produce an error 16196 message if used. 16197 * GCC 3.3.1 automatically places zero-initialized variables in the 16198 .bss section on some operating systems. Versions of GNU Emacs up to 16199 (and including) 21.3 will not work correctly when using this 16200 optimization; you can use -fno-zero-initialized-in-bss to disable 16201 it. 16202 16203 General Optimizer Improvements 16204 16205 * A new scheme for accurately describing processor pipelines, the 16206 [5]DFA scheduler, has been added. 16207 * Pavel Nejedly, Charles University Prague, has contributed new file 16208 format used by the edge coverage profiler (-fprofile-arcs). 16209 The new format is robust and diagnoses common mistakes where 16210 profiles from different versions (or compilations) of the program 16211 are combined resulting in nonsensical profiles and slow code to 16212 produced with profile feedback. Additionally this format allows 16213 extra data to be gathered. Currently, overall statistics are 16214 produced helping optimizers to identify hot spots of a program 16215 globally replacing the old intra-procedural scheme and resulting in 16216 better code. Note that the gcov tool from older GCC versions will 16217 not be able to parse the profiles generated by GCC 3.3 and vice 16218 versa. 16219 * Jan Hubicka, SuSE Labs, has contributed a new superblock formation 16220 pass enabled using -ftracer. This pass simplifies the control flow 16221 of functions allowing other optimizations to do better job. 16222 He also contributed the function reordering pass 16223 (-freorder-functions) to optimize function placement using profile 16224 feedback. 16225 16226 New Languages and Language specific improvements 16227 16228 C/ObjC/C++ 16229 16230 * The preprocessor now accepts directives within macro arguments. It 16231 processes them just as if they had not been within macro arguments. 16232 * The separate ISO and traditional preprocessors have been completely 16233 removed. The front end handles either type of preprocessed output 16234 if necessary. 16235 * In C99 mode preprocessor arithmetic is done in the precision of the 16236 target's intmax_t, as required by that standard. 16237 * The preprocessor can now copy comments inside macros to the output 16238 file when the macro is expanded. This feature, enabled using the 16239 -CC option, is intended for use by applications which place 16240 metadata or directives inside comments, such as lint. 16241 * The method of constructing the list of directories to be searched 16242 for header files has been revised. If a directory named by a -I 16243 option is a standard system include directory, the option is 16244 ignored to ensure that the default search order for system 16245 directories and the special treatment of system header files are 16246 not defeated. 16247 * A few more [6]ISO C99 features now work correctly. 16248 * A new function attribute, nonnull, has been added which allows 16249 pointer arguments to functions to be specified as requiring a 16250 non-null value. The compiler currently uses this information to 16251 issue a warning when it detects a null value passed in such an 16252 argument slot. 16253 * A new type attribute, may_alias, has been added. Accesses to 16254 objects with types with this attribute are not subjected to 16255 type-based alias analysis, but are instead assumed to be able to 16256 alias any other type of objects, just like the char type. 16257 16258 C++ 16259 16260 * Type based alias analysis has been implemented for C++ aggregate 16261 types. 16262 16263 Objective-C 16264 16265 * Generate an error if Objective-C objects are passed by value in 16266 function and method calls. 16267 * When -Wselector is used, check the whole list of selectors at the 16268 end of compilation, and emit a warning if a @selector() is not 16269 known. 16270 * Define __NEXT_RUNTIME__ when compiling for the NeXT runtime. 16271 * No longer need to include objc/objc-class.h to compile self calls 16272 in class methods (NeXT runtime only). 16273 * New -Wundeclared-selector option. 16274 * Removed selector bloating which was causing object files to be 10% 16275 bigger on average (GNU runtime only). 16276 * Using at run time @protocol() objects has been fixed in certain 16277 situations (GNU runtime only). 16278 * Type checking has been fixed and improved in many situations 16279 involving protocols. 16280 16281 Java 16282 16283 * The java.sql and javax.sql packages now implement the JDBC 3.0 (JDK 16284 1.4) API. 16285 * The JDK 1.4 assert facility has been implemented. 16286 * The bytecode interpreter is now direct threaded and thus faster. 16287 16288 Fortran 16289 16290 * Fortran improvements are listed in [7]the Fortran documentation. 16291 16292 Ada 16293 16294 * Ada tasking now works with glibc 2.3.x threading libraries. 16295 16296 New Targets and Target Specific Improvements 16297 16298 * The following changes have been made to the HP-PA port: 16299 + The port now defaults to scheduling for the PA8000 series of 16300 processors. 16301 + Scheduling support for the PA7300 processor has been added. 16302 + The 32-bit port now supports weak symbols under HP-UX 11. 16303 + The handling of initializers and finalizers has been improved 16304 under HP-UX 11. The 64-bit port no longer uses collect2. 16305 + Dwarf2 EH support has been added to the 32-bit GNU/Linux port. 16306 + ABI fixes to correct the passing of small structures by value. 16307 * The SPARC, HP-PA, SH4, and x86/pentium ports have been converted to 16308 use the DFA processor pipeline description. 16309 * The following NetBSD configurations for the SuperH processor family 16310 have been added: 16311 + SH3, big-endian, sh-*-netbsdelf* 16312 + SH3, little-endian, shle-*-netbsdelf* 16313 + SH5, SHmedia, big-endian, 32-bit default, sh5-*-netbsd* 16314 + SH5, SHmedia, little-endian, 32-bit default, sh5le-*-netbsd* 16315 + SH5, SHmedia, big-endian, 64-bit default, sh64-*-netbsd* 16316 + SH5, SHmedia, little-endian, 64-bit default, sh64le-*-netbsd* 16317 * The following changes have been made to the IA-32/x86-64 port: 16318 + SSE2 and 3dNOW! intrinsics are now supported. 16319 + Support for thread local storage has been added to the IA-32 16320 and x86-64 ports. 16321 + The x86-64 port has been significantly improved. 16322 * The following changes have been made to the MIPS port: 16323 + All configurations now accept the -mabi switch. Note that you 16324 will need appropriate multilibs for this option to work 16325 properly. 16326 + ELF configurations will always pass an ABI flag to the 16327 assembler, except when the MIPS EABI is selected. 16328 + -mabi=64 no longer selects MIPS IV code. 16329 + The -mcpu option, which was deprecated in 3.1 and 3.2, has 16330 been removed from this release. 16331 + -march now changes the core ISA level. In previous releases, 16332 it would change the use of processor-specific extensions, but 16333 would leave the core ISA unchanged. For example, mips64-elf 16334 -march=r8000 will now generate MIPS IV code. 16335 + Under most configurations, -mipsN now acts as a synonym for 16336 -march. 16337 + There are some new preprocessor macros to describe the -march 16338 and -mtune settings. See the documentation of those options 16339 for details. 16340 + Support for the NEC VR-Series processors has been added. This 16341 includes the 54xx, 5500, and 41xx series. 16342 + Support for the Sandcraft sr71k processor has been added. 16343 * The following changes have been made to the S/390 port: 16344 + Support to build the Java runtime libraries has been added. 16345 Java is now enabled by default on s390-*-linux* and 16346 s390x-*-linux* targets. 16347 + Multilib support for the s390x-*-linux* target has been added; 16348 this allows to build 31-bit binaries using the -m31 option. 16349 + Support for thread local storage has been added. 16350 + Inline assembler code may now use the 'Q' constraint to 16351 specify memory operands without index register. 16352 + Various platform-specific performance improvements have been 16353 implemented; in particular, the compiler now uses the BRANCH 16354 ON COUNT family of instructions and makes more frequent use of 16355 the TEST UNDER MASK family of instructions. 16356 * The following changes have been made to the PowerPC port: 16357 + Support for IBM Power4 processor added. 16358 + Support for Motorola e500 SPE added. 16359 + Support for AIX 5.2 added. 16360 + Function and Data sections now supported on AIX. 16361 + Sibcall optimizations added. 16362 * The support for H8 Tiny is added to the H8/300 port with -mn. 16363 16364 Obsolete Systems 16365 16366 Support for a number of older systems has been declared obsolete in GCC 16367 3.3. Unless there is activity to revive them, the next release of GCC 16368 will have their sources permanently removed. 16369 16370 All configurations of the following processor architectures have been 16371 declared obsolete: 16372 * Matsushita MN10200, mn10200-*-* 16373 * Motorola 88000, m88k-*-* 16374 * IBM ROMP, romp-*-* 16375 16376 Also, some individual systems have been obsoleted: 16377 * Alpha 16378 + Interix, alpha*-*-interix* 16379 + Linux libc1, alpha*-*-linux*libc1* 16380 + Linux ECOFF, alpha*-*-linux*ecoff* 16381 * ARM 16382 + Generic a.out, arm*-*-aout* 16383 + Conix, arm*-*-conix* 16384 + "Old ABI," arm*-*-oabi 16385 + StrongARM/COFF, strongarm-*-coff* 16386 * HPPA (PA-RISC) 16387 + Generic OSF, hppa1.0-*-osf* 16388 + Generic BSD, hppa1.0-*-bsd* 16389 + HP/UX versions 7, 8, and 9, hppa1.[01]-*-hpux[789]* 16390 + HiUX, hppa*-*-hiux* 16391 + Mach Lites, hppa*-*-lites* 16392 * Intel 386 family 16393 + Windows NT 3.x, i?86-*-win32 16394 * MC68000 family 16395 + HP systems, m68000-hp-bsd* and m68k-hp-bsd* 16396 + Sun systems, m68000-sun-sunos*, m68k-sun-sunos*, and 16397 m68k-sun-mach* 16398 + AT&T systems, m68000-att-sysv* 16399 + Atari systems, m68k-atari-sysv* 16400 + Motorola systems, m68k-motorola-sysv* 16401 + NCR systems, m68k-ncr-sysv* 16402 + Plexus systems, m68k-plexus-sysv* 16403 + Commodore systems, m68k-cbm-sysv* 16404 + Citicorp TTI, m68k-tti-* 16405 + Unos, m68k-crds-unos* 16406 + Concurrent RTU, m68k-ccur-rtu* 16407 + Linux a.out, m68k-*-linux*aout* 16408 + Linux libc1, m68k-*-linux*libc1* 16409 + pSOS, m68k-*-psos* 16410 * MIPS 16411 + Generic ECOFF, mips*-*-ecoff* 16412 + SINIX, mips-sni-sysv4 16413 + Orion RTEMS, mips64orion-*-rtems* 16414 * National Semiconductor 32000 16415 + OpenBSD, ns32k-*-openbsd* 16416 * POWER (aka RS/6000) and PowerPC 16417 + AIX versions 1, 2, and 3, rs6000-ibm-aix[123]* 16418 + Bull BOSX, rs6000-bull-bosx 16419 + Generic Mach, rs6000-*-mach* 16420 + Generic SysV, powerpc*-*-sysv* 16421 + Linux libc1, powerpc*-*-linux*libc1* 16422 * Sun SPARC 16423 + Generic a.out, sparc-*-aout*, sparclet-*-aout*, 16424 sparclite-*-aout*, and sparc86x-*-aout* 16425 + NetBSD a.out, sparc-*-netbsd*aout* 16426 + Generic BSD, sparc-*-bsd* 16427 + ChorusOS, sparc-*-chorusos* 16428 + Linux a.out, sparc-*-linux*aout* 16429 + Linux libc1, sparc-*-linux*libc1* 16430 + LynxOS, sparc-*-lynxos* 16431 + Solaris on HAL hardware, sparc-hal-solaris2* 16432 + SunOS versions 3 and 4, sparc-*-sunos[34]* 16433 * NEC V850 16434 + RTEMS, v850-*-rtems* 16435 * VAX 16436 + VMS, vax-*-vms* 16437 16438 Documentation improvements 16439 16440 Other significant improvements 16441 16442 * Almost all front-end dependencies in the compiler have been 16443 separated out into a set of language hooks. This should make adding 16444 a new front end clearer and easier. 16445 * One effect of removing the separate preprocessor is a small 16446 increase in the robustness of the compiler in general, and the 16447 maintainability of target descriptions. Previously target-specific 16448 built-in macros and others, such as __FAST_MATH__, had to be 16449 handled with so-called specs that were hard to maintain. Often they 16450 would fail to behave properly when conflicting options were 16451 supplied on the command line, and define macros in the user's 16452 namespace even when strict ISO compliance was requested. 16453 Integrating the preprocessor has cleanly solved these issues. 16454 * The Makefile suite now supports redirection of make install by 16455 means of the variable DESTDIR. 16456 __________________________________________________________________ 16457 16458 GCC 3.3 16459 16460 Detailed release notes for the GCC 3.3 release follow. 16461 16462 Bug Fixes 16463 16464 bootstrap failures 16465 16466 * [8]10140 cross compiler build failures: missing __mempcpy (DUP: 16467 [9]10198,[10]10338) 16468 16469 Internal compiler errors (multi-platform) 16470 16471 * [11]3581 large string causes segmentation fault in cc1 16472 * [12]4382 __builtin_{set,long}jmp with -O3 can crash the compiler 16473 * [13]5533 (c++) ICE when processing std::accumulate(begin, end, 16474 init, invalid_op) 16475 * [14]6387 -fpic -gdwarf-2 -g1 combination gives ICE in dwarf2out 16476 * [15]6412 (c++) ICE in retrieve_specialization 16477 * [16]6620 (c++) partial template specialization causes an ICE 16478 (segmentation fault) 16479 * [17]6663 (c++) ICE with attribute aligned 16480 * [18]7068 ICE with incomplete types 16481 * [19]7083 (c++) ICE using -gstabs with dodgy class derivation 16482 * [20]7647 (c++) ICE when data member has the name of the enclosing 16483 class 16484 * [21]7675 ICE in fixup_var_refs_1 16485 * [22]7718 'complex' template instantiation causes ICE 16486 * [23]8116 (c++) ICE in member template function 16487 * [24]8358 (ada) Ada compiler accesses freed memory, crashes 16488 * [25]8511 (c++) ICE: (hopefully) reproducible cc1plus segmentation 16489 fault 16490 * [26]8564 (c++) ICE in find_function_data, in function.c 16491 * [27]8660 (c++) template overloading ICE in tsubst_expr, in cp/pt.c 16492 * [28]8766 (c++) ICE after failed initialization of static template 16493 variable 16494 * [29]8803 ICE in instantiate_virtual_regs_1, in function.c 16495 * [30]8846 (c++) ICE after diagnostic if fr_FR@euro locale is set 16496 * [31]8906 (c++) ICE (Segmentation fault) when parsing nested-class 16497 definition 16498 * [32]9216 (c++) ICE on missing template parameter 16499 * [33]9261 (c++) ICE in arg_assoc, in cp/decl2.c 16500 * [34]9263 (fortran) ICE caused by invalid PARAMETER in implied DO 16501 loop 16502 * [35]9429 (c++) ICE in template instantiation with a pointered new 16503 operator 16504 * [36]9516 Internal error when using a big array 16505 * [37]9600 (c++) ICE with typedefs in template class 16506 * [38]9629 (c++) virtual inheritance segfault 16507 * [39]9672 (c++) ICE: Error reporting routines re-entered 16508 * [40]9749 (c++) ICE in write_expression on invalid function 16509 prototype 16510 * [41]9794 (fortran) ICE: floating point exception during constant 16511 folding 16512 * [42]9829 (c++) Missing colon in nested namespace usage causes ICE 16513 * [43]9916 (c++) ICE with noreturn function in ?: statement 16514 * [44]9936 ICE with local function and variable-length 2d array 16515 * [45]10262 (c++) cc1plus crashes with large generated code 16516 * [46]10278 (c++) ICE in parser for invalid code 16517 * [47]10446 (c++) ICE on definition of nonexistent member function of 16518 nested class in a class template 16519 * [48]10451 (c++) ICE in grokdeclarator on spurious mutable 16520 declaration 16521 * [49]10506 (c++) ICE in build_new at cp/init.c with 16522 -fkeep-inline-functions and multiple inheritance 16523 * [50]10549 (c++) ICE in store_bit_field on bitfields that exceed the 16524 precision of the declared type 16525 16526 Optimization bugs 16527 16528 * [51]2001 Inordinately long compile times in reload CSE regs 16529 * [52]2391 Exponential compilation time explosion in combine 16530 * [53]2960 Duplicate loop conditions even with -Os 16531 * [54]4046 redundant conditional branch 16532 * [55]6405 Loop-unrolling related performance regressions 16533 * [56]6798 very long compile time with large case-statement 16534 * [57]6871 const objects shouldn't be moved to .bss 16535 * [58]6909 problem w/ -Os on modified loop-2c.c test case 16536 * [59]7189 gcc -O2 -Wall does not print ``control reaches end of 16537 non-void function'' warning 16538 * [60]7642 optimization problem with signbit() 16539 * [61]8634 incorrect code for inlining of memcpy under -O2 16540 * [62]8750 Cygwin prolog generation erroneously emitting __alloca as 16541 regular function call 16542 16543 C front end 16544 16545 * [63]2161 long if-else cascade overflows parser stack 16546 * [64]4319 short accepted on typedef'd char 16547 * [65]8602 incorrect line numbers in warning messages when using 16548 inline functions 16549 * [66]9177 -fdump-translation-unit: C front end deletes function_decl 16550 AST nodes and breaks debugging dumps 16551 * [67]9853 miscompilation of non-constant structure initializer 16552 16553 c++ compiler and library 16554 16555 * [68]45 legal template specialization code is rejected (DUP: 16556 [69]3784) 16557 * [70]764 lookup failure: friend operator and dereferencing a pointer 16558 and templates (DUP: [71]5116) 16559 * [72]2862 gcc accepts invalid explicit instantiation syntax (DUP: 16560 2863) 16561 * [73]3663 G++ doesn't check access control during template 16562 instantiation 16563 * [74]3797 gcc fails to emit explicit specialization of a template 16564 member 16565 * [75]3948 Two destructors are called when no copy destructor is 16566 defined (ABI change) 16567 * [76]4137 Conversion operator within template is not accepted 16568 * [77]4361 bogus ambiguity taking the address of a member template 16569 * [78]4802 g++ accepts illegal template code (access to private 16570 member; DUP: [79]5837) 16571 * [80]4803 inline function is used but never defined, and g++ does 16572 not object 16573 * [81]5094 Partial specialization cannot be friend? 16574 * [82]5730 complex<double>::norm() -- huge slowdown from egcs-2.91.66 16575 * [83]6713 Regression wrt 3.0.4: g++ -O2 leads to seg fault at run 16576 time 16577 * [84]7015 certain __asm__ constructs rejected 16578 * [85]7086 compile time regression (quadratic behavior in 16579 fixup_var_refs) 16580 * [86]7099 G++ doesn't set the noreturn attribute on std::exit and 16581 std::abort 16582 * [87]7247 copy constructor missing when inlining enabled (invalid 16583 optimization?) 16584 * [88]7441 string array initialization compilation time regression 16585 from seconds to minutes 16586 * [89]7768 __PRETTY_FUNCTION__ for template destructor is wrong 16587 * [90]7804 bad printing of floating point constant in warning message 16588 * [91]8099 Friend classes and template specializations 16589 * [92]8117 member function pointers and multiple inheritance 16590 * [93]8205 using declaration and multiple inheritance 16591 * [94]8645 unnecessary non-zero checks in stl_tree.h 16592 * [95]8724 explicit destructor call for incomplete class allowed 16593 * [96]8805 compile time regression with many member variables 16594 * [97]8691 -O3 and -fno-implicit-templates are incompatible 16595 * [98]8700 unhelpful error message for binding temp to reference 16596 * [99]8724 explicit destructor call for incomplete class allowed 16597 * [100]8949 numeric_limits<>::denorm_min() and is_iec559 problems 16598 * [101]9016 Failure to consistently constant fold "constant" C++ 16599 objects 16600 * [102]9053 g++ confused about ambiguity of overloaded function 16601 templates 16602 * [103]9152 undefined virtual thunks 16603 * [104]9182 basic_filebuf<> does not report errors in codecvt<>::out 16604 * [105]9297 data corruption due to codegen bug (when copying.) 16605 * [106]9318 i/ostream::operator>>/<<(streambuf*) broken 16606 * [107]9320 Incorrect usage of traits_type::int_type in stdio_filebuf 16607 * [108]9400 bogus -Wshadow warning: shadowed declaration of this in 16608 local classes 16609 * [109]9424 i/ostream::operator>>/<<(streambuf*) drops characters 16610 * [110]9425 filebuf::pbackfail broken (DUP: [111]9439) 16611 * [112]9474 GCC freezes in compiling a weird code mixing <iostream> 16612 and <iostream.h> 16613 * [113]9548 Incorrect results from setf(ios::fixed) and precision(-1) 16614 [114][DR 231] 16615 * [115]9555 ostream inserters fail to set badbit on exception 16616 * [116]9561 ostream inserters rethrow exception of wrong type 16617 * [117]9563 ostream::sentry returns true after a failed preparation 16618 * [118]9582 one-definition rule violation in std::allocator 16619 * [119]9622 __PRETTY_FUNCTION__ incorrect in template destructors 16620 * [120]9683 bug in initialization chains for static const variables 16621 from template classes 16622 * [121]9791 -Woverloaded-virtual reports hiding of destructor 16623 * [122]9817 collate::compare doesn't handle nul characters 16624 * [123]9825 filebuf::sputbackc breaks sbumpc 16625 * [124]9826 operator>>(basic_istream, basic_string) fails to compile 16626 with custom traits 16627 * [125]9924 Multiple using statements for builtin functions not 16628 allowed 16629 * [126]9946 destructor is not called for temporary object 16630 * [127]9964 filebuf::close() sometimes fails to close file 16631 * [128]9988 filebuf::overflow writes EOF to file 16632 * [129]10033 optimization breaks polymorphic references w/ typeid 16633 operator 16634 * [130]10097 filebuf::underflow drops characters 16635 * [131]10132 filebuf destructor can throw exceptions 16636 * [132]10180 gcc fails to warn about non-inlined function 16637 * [133]10199 method parametrized by template does not work everywhere 16638 * [134]10300 use of array-new (nothrow) in segfaults on NULL return 16639 * [135]10427 Stack corruption with variable-length automatic arrays 16640 and virtual destructors 16641 * [136]10503 Compilation never stops in fixed_type_or_null 16642 16643 Objective-C 16644 16645 * [137]5956 selectors aren't matched properly when added to the 16646 selector table 16647 16648 Fortran compiler and library 16649 16650 * [138]1832 list directed i/o overflow hangs, -fbounds-check doesn't 16651 detect 16652 * [139]3924 g77 generates code that is rejected by GAS if COFF debug 16653 info requested 16654 * [140]5634 doc: explain that configure --prefix=~/... does not work 16655 * [141]6367 multiple repeat counts confuse namelist read into array 16656 * [142]6491 Logical operations error on logicals when using 16657 -fugly-logint 16658 * [143]6742 Generation of C++ Prototype for FORTRAN and extern "C" 16659 * [144]7113 Failure of g77.f-torture/execute/f90-intrinsic-bit.f -Os 16660 on irix6.5 16661 * [145]7236 OPEN(...,RECL=nnn,...) without ACCESS='DIRECT' should 16662 assume a direct access file 16663 * [146]7278 g77 "bug"; the executable misbehaves (with -O2 16664 -fno-automatic) 16665 * [147]7384 DATE_AND_TIME milliseconds field inactive on Windows 16666 * [148]7388 Incorrect output with 0-based array of characters 16667 * [149]8587 Double complex zero ** double precision number -> NaN 16668 instead of zero 16669 * [150]9038 -ffixed-line-length-none -x f77-cpp-input gives: Warning: 16670 unknown register name line-length-none 16671 * [151]10197 Direct access files not unformatted by default 16672 16673 Java compiler and library 16674 16675 * [152]6005 gcj fails to build rhug on alpha 16676 * [153]6389 System.getProperty("") should always throw an 16677 IllegalArgumentException 16678 * [154]6576 java.util.ResourceBundle.getResource ignores locale 16679 * [155]6652 new java.io.File("").getCanonicalFile() throws exception 16680 * [156]7060 getMethod() doesn't search super interface 16681 * [157]7073 bytecode interpreter gives wrong answer for interface 16682 getSuperclass() 16683 * [158]7180 possible bug in 16684 javax.naming.spi.NamingManager.getPlusPath() 16685 * [159]7416 java.security startup refs "GNU libgcj.security" 16686 * [160]7570 Runtime.exec with null envp: child doesn't inherit parent 16687 env (DUP: [161]7578) 16688 * [162]7611 Internal error while compiling libjava with -O 16689 * [163]7709 NullPointerException in _Jv_ResolvePoolEntry 16690 * [164]7766 ZipInputStream.available returns 0 immediately after 16691 construction 16692 * [165]7785 Calendar.getTimeInMillis/setTimeInMillis should be public 16693 * [166]7786 TimeZone.getDSTSavings() from JDK1.4 not implemented 16694 * [167]8142 '$' in class names vs. dlopen 'dynamic string tokens' 16695 * [168]8234 ZipInputStream chokes when InputStream.read() returns 16696 small chunks 16697 * [169]8415 reflection bug: exception info for Method 16698 * [170]8481 java.Random.nextInt(int) may return negative 16699 * [171]8593 Error reading GZIPped files with BufferedReader 16700 * [172]8759 java.beans.Introspector has no flushCaches() or 16701 flushFromCaches() methods 16702 * [173]8997 spin() calls Thread.sleep 16703 * [174]9253 on win32, java.io.File.listFiles("C:\\") returns pwd 16704 instead of the root content of C: 16705 * [175]9254 java::lang::Object::wait(), threads-win32.cc returns 16706 wrong return codes 16707 * [176]9271 Severe bias in java.security.SecureRandom 16708 16709 Ada compiler and library 16710 16711 * [177]6767 make gnatlib-shared fails on -laddr2line 16712 * [178]9911 gnatmake fails to link when GCC configured with 16713 --with-sjlj-exceptions=yes 16714 * [179]10020 Can't bootstrap gcc on AIX with Ada enabled 16715 * [180]10546 Ada tasking not working on Red Hat 9 16716 16717 preprocessor 16718 16719 * [181]7029 preprocessor should ignore #warning with -M 16720 16721 ARM-specific 16722 16723 * [182]2903 [arm] Optimization bug with long long arithmetic 16724 * [183]7873 arm-linux-gcc fails when assigning address to a bit field 16725 16726 FreeBSD-specific 16727 16728 * [184]7680 float functions undefined in math.h/cmath with #define 16729 _XOPEN_SOURCE 16730 16731 HP-UX or HP-PA-specific 16732 16733 * [185]8705 [HP-PA] ICE in emit_move_insn_1, in expr.c 16734 * [186]9986 [HP-UX] Incorrect transformation of fputs_unlocked to 16735 fputc_unlocked 16736 * [187]10056 [HP-PA] ICE at -O2 when building c++ code from doxygen 16737 16738 m68hc11-specific 16739 16740 * [188]6744 Bad assembler code generated: reference to pseudo 16741 register z 16742 * [189]7361 Internal compiler error in reload_cse_simplify_operands, 16743 in reload1.c 16744 16745 MIPS-specific 16746 16747 * [190]9496 [mips-linux] bug in optimizer? 16748 16749 PowerPC-specific 16750 16751 * [191]7067 -Os with -mcpu=powerpc optimizes for speed (?) instead of 16752 space 16753 * [192]8480 reload ICEs for LAPACK code on powerpc64-linux 16754 * [193]8784 [AIX] Internal compiler error in simplify_gen_subreg 16755 * [194]10315 [powerpc] ICE: in extract_insn, in recog.c 16756 16757 SPARC-specific 16758 16759 * [195]10267 (documentation) Wrong build instructions for 16760 *-*-solaris2* 16761 16762 x86-specific (Intel/AMD) 16763 16764 * [196]7916 ICE in instantiate_virtual_register_1 16765 * [197]7926 (c++) i486 instructions in header files make c++ programs 16766 crash on i386 16767 * [198]8555 ICE in gen_split_1231 16768 * [199]8994 ICE with -O -march=pentium4 16769 * [200]9426 ICE with -fssa -funroll-loops -fprofile-arcs 16770 * [201]9806 ICE in inline assembly with -fPIC flag 16771 * [202]10077 gcc -msse2 generates movd to move dwords between xmm 16772 regs 16773 * [203]10233 64-bit comparison only comparing bottom 32-bits 16774 * [204]10286 type-punning doesn't work with __m64 and -O 16775 * [205]10308 [x86] ICE with -O -fgcse or -O2 16776 __________________________________________________________________ 16777 16778 GCC 3.3.1 16779 16780 Bug Fixes 16781 16782 This section lists the problem reports (PRs) from GCC's bug tracking 16783 system that are known to be fixed in the 3.3.1 release. This list might 16784 not be complete (that is, it is possible that some PRs that have been 16785 fixed are not listed here). 16786 16787 Bootstrap failures 16788 16789 * [206]11272 [Solaris] make bootstrap fails while building libstdc++ 16790 16791 Internal compiler errors (multi-platform) 16792 16793 * [207]5754 ICE on invalid nested template class 16794 * [208]6597 ICE in set_mem_alias_set compiling Qt with -O2 on ia64 16795 and --enable-checking 16796 * [209]6949 (c++) ICE in tsubst_decl, in cp/pt.c 16797 * [210]7053 (c++) ICE when declaring a function already defined as a 16798 friend method of a template class 16799 * [211]8164 (c++) ICE when using different const expressions as 16800 template parameter 16801 * [212]8384 (c++) ICE in is_base_type, in dwarf2out.c 16802 * [213]9559 (c++) ICE with invalid initialization of a static const 16803 * [214]9649 (c++) ICE in finish_member_declaration, in cp/semantics.c 16804 when redeclaring a static member variable 16805 * [215]9864 (fortran) ICE in add_abstract_origin_attribute, in 16806 dwarfout.c with -g -O -finline-functions 16807 * [216]10432 (c++) ICE in poplevel, in cp/decl.c 16808 * [217]10475 ICE in subreg_highpart_offset for code with long long 16809 * [218]10635 (c++) ICE when dereferencing an incomplete type casted 16810 from a void pointer 16811 * [219]10661 (c++) ICE in instantiate_decl, in cp/pt.c while 16812 instantiating static member variables 16813 * [220]10700 ICE in copy_to_mode_reg on 64-bit targets 16814 * [221]10712 (c++) ICE in constructor_name_full, in cp/decl2.c 16815 * [222]10796 (c++) ICE when defining an enum with two values: -1 and 16816 MAX_INT_64BIT 16817 * [223]10890 ICE in merge_assigned_reloads building Linux 2.4.2x 16818 sched.c 16819 * [224]10939 (c++) ICE with template code 16820 * [225]10956 (c++) ICE when specializing a template member function 16821 of a template class, in tsubst, in cp/pt.c 16822 * [226]11041 (c++) ICE: const myclass &x = *x; (when operator*() 16823 defined) 16824 * [227]11059 (c++) ICE with empty union 16825 * [228]11083 (c++) ICE in commit_one_edge_insertion, in cfgrtl.c with 16826 -O2 -fnon-call-exceptions 16827 * [229]11105 (c++) ICE in mangle_conv_op_name_for_type 16828 * [230]11149 (c++) ICE on error when instantiation with call function 16829 of a base type 16830 * [231]11228 (c++) ICE on new-expression using array operator new and 16831 default-initialization 16832 * [232]11282 (c++) Infinite memory usage after syntax error 16833 * [233]11301 (fortran) ICE with -fno-globals 16834 * [234]11308 (c++) ICE when using an enum type name as if it were a 16835 class or namespace 16836 * [235]11473 (c++) ICE with -gstabs when empty struct inherits from 16837 an empty struct 16838 * [236]11503 (c++) ICE when instantiating template with ADDR_EXPR 16839 * [237]11513 (c++) ICE in push_template_decl_real, in cp/pt.c: 16840 template member functions 16841 16842 Optimization bugs 16843 16844 * [238]11198 -O2 -frename-registers generates wrong code (aliasing 16845 problem) 16846 * [239]11304 Wrong code production with -fomit-frame-pointer 16847 * [240]11381 volatile memory access optimized away 16848 * [241]11536 [strength-reduce] -O2 optimization produces wrong code 16849 * [242]11557 constant folding bug generates wrong code 16850 16851 C front end 16852 16853 * [243]5897 No warning for statement after return 16854 * [244]11279 DWARF-2 output mishandles large enums 16855 16856 Preprocessor bugs 16857 16858 * [245]11022 no warning for non-compatible macro redefinition 16859 16860 C++ compiler and library 16861 16862 * [246]2330 static_cast<>() to a private base is allowed 16863 * [247]5388 Incorrect message "operands to ?: have different types" 16864 * [248]5390 Libiberty fails to demangle multi-digit template 16865 parameters 16866 * [249]7877 Incorrect parameter passing to specializations of member 16867 function templates 16868 * [250]9393 Anonymous namespaces and compiling the same file twice 16869 * [251]10032 -pedantic converts some errors to warnings 16870 * [252]10468 const typeof(x) is non-const, but only in templates 16871 * [253]10527 confused error message with "new int()" parameter 16872 initializer 16873 * [254]10679 parameter MIN_INLINE_INSNS is not honored 16874 * [255]10682 gcc chokes on a typedef for an enum inside a class 16875 template 16876 * [256]10689 pow(std::complex(0),1/3) returns (nan, nan) instead of 16877 0. 16878 * [257]10845 template member function (with nested template as 16879 parameter) cannot be called anymore if another unrelated template 16880 member function is defined 16881 * [258]10849 Cannot define an out-of-class specialization of a 16882 private nested template class 16883 * [259]10888 Suppress -Winline warnings for system headers 16884 * [260]10929 -Winline warns about functions for which no definition 16885 is visible 16886 * [261]10931 valid conversion static_cast<const unsigned 16887 int&>(lvalue-of-type-int) is rejected 16888 * [262]10940 Bad code with explicit specialization 16889 * [263]10968 If member function implicitly instantiated, explicit 16890 instantiation of class fails to instantiate it 16891 * [264]10990 Cannot convert with dynamic_cast<> to a private base 16892 class from within a member function 16893 * [265]11039 Bad interaction between implicit typename deprecation 16894 and friendship 16895 * [266]11062 (libstdc++) avoid __attribute__ ((unused)); say 16896 "__unused__" instead 16897 * [267]11095 C++ iostream manipulator causes segfault when called 16898 with negative argument 16899 * [268]11098 g++ doesn't emit complete debugging information for 16900 local variables in destructors 16901 * [269]11137 GNU/Linux shared library constructors not called unless 16902 there's one global object 16903 * [270]11154 spurious ambiguity report for template class 16904 specialization 16905 * [271]11329 Compiler cannot find user defined implicit typecast 16906 * [272]11332 Spurious error with casts in ?: expression 16907 * [273]11431 static_cast behavior with subclasses when default 16908 constructor available 16909 * [274]11528 money_get facet does not accept "$.00" as valid 16910 * [275]11546 Type lookup problems in out-of-line definition of a 16911 class doubly nested from a template class 16912 * [276]11567 C++ code containing templated member function with same 16913 name as pure virtual member function results in linking failure 16914 * [277]11645 Failure to deal with using and private inheritance 16915 16916 Java compiler and library 16917 16918 * [278]5179 Qualified static field access doesn't initialize its 16919 class 16920 * [279]8204 gcj -O2 to native reorders certain instructions 16921 improperly 16922 * [280]10838 java.io.ObjectInputStream syntax error 16923 * [281]10886 The RMI registry that comes with GCJ does not work 16924 correctly 16925 * [282]11349 JNDI URL context factories not located correctly 16926 16927 x86-specific (Intel/AMD) 16928 16929 * [283]4823 ICE on inline assembly code 16930 * [284]8878 miscompilation with -O and SSE 16931 * [285]9815 (c++ library) atomicity.h - fails to compile with -O3 16932 -masm=intel 16933 * [286]10402 (inline assembly) [x86] ICE in merge_assigned_reloads, 16934 in reload1.c 16935 * [287]10504 ICE with SSE2 code and -O3 -mcpu=pentium4 -msse2 16936 * [288]10673 ICE for x86-64 on freebsd libc vfprintf.c source 16937 * [289]11044 [x86] out of range loop instructions for FP code on K6 16938 * [290]11089 ICE: instantiate_virtual_regs_lossage while using SSE 16939 built-ins 16940 * [291]11420 [x86_64] gcc generates invalid asm code when "-O -fPIC" 16941 is used 16942 16943 SPARC- or Solaris- specific 16944 16945 * [292]9362 solaris 'as' dies when fed .s and "-gstabs" 16946 * [293]10142 [SPARC64] gcc produces wrong code when passing 16947 structures by value 16948 * [294]10663 New configure check aborts with Sun tools. 16949 * [295]10835 combinatorial explosion in scheduler on HyperSPARC 16950 * [296]10876 ICE in calculate_giv_inc when building KDE 16951 * [297]10955 wrong code at -O3 for structure argument in context of 16952 structure return 16953 * [298]11018 -mcpu=ultrasparc busts tar-1.13.25 16954 * [299]11556 [sparc64] ICE in gen_reg_rtx() while compiling 2.6.x 16955 Linux kernel 16956 16957 ia64 specific 16958 16959 * [300]10907 gcc violates the ia64 ABI (GP must be preserved) 16960 * [301]11320 scheduler bug (in machine depended reorganization pass) 16961 * [302]11599 bug with conditional and __builtin_prefetch 16962 16963 PowerPC specific 16964 16965 * [303]9745 [powerpc] gcc mis-compiles libmcrypt (alias problem 16966 during loop) 16967 * [304]10871 error in rs6000_stack_info save_size computation 16968 * [305]11440 gcc mis-compiles c++ code (libkhtml) with -O2, -fno-gcse 16969 cures it 16970 16971 m68k-specific 16972 16973 * [306]7594 [m68k] ICE on legal code associated with simplify-rtx 16974 * [307]10557 [m68k] ICE in subreg_offset_representable_p 16975 * [308]11054 [m68k] ICE in reg_overlap_mentioned_p 16976 16977 ARM-specific 16978 16979 * [309]10834 [arm] GCC 3.3 still generates incorrect instructions for 16980 functions with __attribute__ ((interrupt ("IRQ"))) 16981 * [310]10842 [arm] Clobbered link register is copied to pc under 16982 certain circumstances 16983 * [311]11052 [arm] noce_process_if_block() can lose REG_INC notes 16984 * [312]11183 [arm] ICE in change_address_1 (3.3) / subreg_hard_regno 16985 (3.4) 16986 16987 MIPS-specific 16988 16989 * [313]11084 ICE in propagate_one_insn, in flow.c 16990 16991 SH-specific 16992 16993 * [314]10331 can't compile c++ part of gcc cross compiler for sh-elf 16994 * [315]10413 [SH] ICE in reload_cse_simplify_operands, in reload1.c 16995 * [316]11096 i686-linux to sh-linux cross compiler fails to compile 16996 C++ files 16997 16998 GNU/Linux (or Hurd?) specific 16999 17000 * [317]2873 Bogus fixinclude of stdio.h from glibc 2.2.3 17001 17002 UnixWare specific 17003 17004 * [318]3163 configure bug: gcc/aclocal.m4 mmap test fails on UnixWare 17005 7.1.1 17006 17007 Cygwin (or mingw) specific 17008 17009 * [319]5287 ICE with dllimport attribute 17010 * [320]10148 [MingW/CygWin] Compiler dumps core 17011 17012 DJGPP specific 17013 17014 * [321]8787 GCC fails to emit .intel_syntax when invoked with 17015 -masm=intel on DJGPP 17016 17017 Darwin (and MacOS X) specific 17018 17019 * [322]10900 trampolines crash 17020 17021 Documentation 17022 17023 * [323]1607 (c++) Format attributes on methods undocumented 17024 * [324]4252 Invalid option `-fdump-translation-unit' 17025 * [325]4490 Clarify restrictions on -m96bit-long-double, 17026 -m128bit-long-double 17027 * [326]10355 document an issue with regparm attribute on some systems 17028 (e.g. Solaris) 17029 * [327]10726 (fortran) Documentation for function "IDate Intrinsic 17030 (Unix)" is wrong 17031 * [328]10805 document bug in old version of Sun assembler 17032 * [329]10815 warn against GNU binutils on AIX 17033 * [330]10877 document need for newer binutils on i?86-*-linux-gnu 17034 * [331]11280 Manual incorrect with respect to -freorder-blocks 17035 * [332]11466 Document -mlittle-endian and its restrictions for the 17036 sparc64 port 17037 17038 Testsuite bugs (compiler itself is not affected) 17039 17040 * [333]10737 newer bison causes g++.dg/parse/crash2.C to incorrectly 17041 report failure 17042 * [334]10810 gcc-3.3 fails make check: buffer overrun in 17043 test_demangle.c 17044 __________________________________________________________________ 17045 17046 GCC 3.3.2 17047 17048 Bug Fixes 17049 17050 This section lists the problem reports (PRs) from GCC's bug tracker 17051 that are known to be fixed in the 3.3.2 release. This list might not be 17052 complete (that is, it is possible that some PRs that have been fixed 17053 are not listed here). 17054 17055 Bootstrap failures and problems 17056 17057 * [335]8336 [SCO5] bootstrap config still tries to use COFF options 17058 * [336]9330 [alpha-osf] Bootstrap failure on Compaq Tru64 with 17059 --enable-threads=posix 17060 * [337]9631 [hppa64-linux] gcc-3.3 fails to bootstrap 17061 * [338]9877 fixincludes makes a bad sys/byteorder.h on svr5 (UnixWare 17062 7.1.1) 17063 * [339]11687 xstormy16-elf build fails in libf2c 17064 * [340]12263 [SGI IRIX] bootstrap fails during compile of 17065 libf2c/libI77/backspace.c 17066 * [341]12490 buffer overflow in scan-decls.c (during Solaris 9 17067 fix-header processing) 17068 17069 Internal compiler errors (multi-platform) 17070 17071 * [342]7277 Casting integers to vector types causes ICE 17072 * [343]7939 (c++) ICE on invalid function template specialization 17073 * [344]11063 (c++) ICE on parsing initialization list of const array 17074 member 17075 * [345]11207 ICE with negative index in array element designator 17076 * [346]11522 (fortran) g77 dwarf-2 ICE in 17077 add_abstract_origin_attribute 17078 * [347]11595 (c++) ICE on duplicate label definition 17079 * [348]11646 (c++) ICE in commit_one_edge_insertion with 17080 -fnon-call-exceptions -fgcse -O 17081 * [349]11665 ICE in struct initializer when taking address 17082 * [350]11852 (c++) ICE with bad struct initializer. 17083 * [351]11878 (c++) ICE in cp_expr_size 17084 * [352]11883 ICE with any -O on mercury-generated C code 17085 * [353]11991 (c++) ICE in cxx_incomplete_type_diagnostic, in 17086 cp/typeck2.c when applying typeid operator to template template 17087 parameter 17088 * [354]12146 ICE in lookup_template_function, in cp/pt.c 17089 * [355]12215 ICE in make_label_edge with -fnon-call-exceptions 17090 -fno-gcse -O2 17091 * [356]12369 (c++) ICE with templates and friends 17092 * [357]12446 ICE in emit_move_insn on complicated array reference 17093 * [358]12510 ICE in final_scan_insn 17094 * [359]12544 ICE with large parameters used in nested functions 17095 17096 C and optimization bugs 17097 17098 * [360]9862 spurious warnings with -W -finline-functions 17099 * [361]10962 lookup_field is a linear search on a linked list (can be 17100 slow if large struct) 17101 * [362]11370 -Wunreachable-code gives false complaints 17102 * [363]11637 invalid assembly with -fnon-call-exceptions 17103 * [364]11885 Problem with bitfields in packed structs 17104 * [365]12082 Inappropriate unreachable code warnings 17105 * [366]12180 Inline optimization fails for variadic function 17106 * [367]12340 loop unroller + gcse produces wrong code 17107 17108 C++ compiler and library 17109 17110 * [368]3907 nested template parameter collides with member name 17111 * [369]5293 confusing message when binding a temporary to a reference 17112 * [370]5296 [DR115] Pointers to functions and to template functions 17113 behave differently in deduction 17114 * [371]7939 ICE on function template specialization 17115 * [372]8656 Unable to assign function with __attribute__ and pointer 17116 return type to an appropriate variable 17117 * [373]10147 Confusing error message for invalid template function 17118 argument 17119 * [374]11400 std::search_n() makes assumptions about Size parameter 17120 * [375]11409 issues with using declarations, overloading, and 17121 built-in functions 17122 * [376]11740 ctype<wchar_t>::do_is(mask, wchar_t) doesn't handle 17123 multiple bits in mask 17124 * [377]11786 operator() call on variable in other namespace not 17125 recognized 17126 * [378]11867 static_cast ignores ambiguity 17127 * [379]11928 bug with conversion operators that are typedefs 17128 * [380]12114 Uninitialized memory accessed in dtor 17129 * [381]12163 static_cast + explicit constructor regression 17130 * [382]12181 Wrong code with comma operator and c++ 17131 * [383]12236 regparm and fastcall messes up parameters 17132 * [384]12266 incorrect instantiation of unneeded template during 17133 overload resolution 17134 * [385]12296 istream::peek() doesn't set eofbit 17135 * [386]12298 [sjlj exceptions] Stack unwind destroys 17136 not-yet-constructed object 17137 * [387]12369 ICE with templates and friends 17138 * [388]12337 apparently infinite loop in g++ 17139 * [389]12344 stdcall attribute ignored if function returns a pointer 17140 * [390]12451 missing(late) class forward declaration in cxxabi.h 17141 * [391]12486 g++ accepts invalid use of a qualified name 17142 17143 x86 specific (Intel/AMD) 17144 17145 * [392]8869 [x86 MMX] ICE with const variable optimization and MMX 17146 builtins 17147 * [393]9786 ICE in fixup_abnormal_edges with -fnon-call-exceptions 17148 -O2 17149 * [394]11689 g++3.3 emits un-assembleable code for k6 architecture 17150 * [395]12116 [k6] Invalid assembly output values with X-MAME code 17151 * [396]12070 ICE converting between double and long double with 17152 -msoft-float 17153 17154 ia64-specific 17155 17156 * [397]11184 [ia64 hpux] ICE on __builtin_apply building libobjc 17157 * [398]11535 __builtin_return_address may not work on ia64 17158 * [399]11693 [ia64] ICE in gen_nop_type 17159 * [400]12224 [ia64] Thread-local storage doesn't work 17160 17161 PowerPC-specific 17162 17163 * [401]11087 [powerpc64-linux] GCC miscompiles raid1.c from linux 17164 kernel 17165 * [402]11319 loop miscompiled on ppc32 17166 * [403]11949 ICE Compiler segfault with ffmpeg -maltivec code 17167 17168 SPARC-specific 17169 17170 * [404]11662 wrong code for expr. with cast to long long and 17171 exclusive or 17172 * [405]11965 invalid assembler code for a shift < 32 operation 17173 * [406]12301 (c++) stack corruption when a returned expression throws 17174 an exception 17175 17176 Alpha-specific 17177 17178 * [407]11717 [alpha-linux] unrecognizable insn compiling for.c of 17179 kernel 2.4.22-pre8 17180 17181 HPUX-specific 17182 17183 * [408]11313 problem with #pragma weak and static inline functions 17184 * [409]11712 __STDC_EXT__ not defined for C++ by default anymore? 17185 17186 Solaris specific 17187 17188 * [410]12166 Profiled programs crash if PROFDIR is set 17189 17190 Solaris-x86 specific 17191 17192 * [411]12101 i386 Solaris no longer works with GNU as? 17193 17194 Miscellaneous embedded target-specific bugs 17195 17196 * [412]10988 [m32r-elf] wrong blockmove code with -O3 17197 * [413]11805 [h8300-unknown-coff] [H8300] ICE for simple code with 17198 -O2 17199 * [414]11902 [sh4] spec file improperly inserts rpath even when none 17200 needed 17201 * [415]11903 [sh4] -pthread fails to link due to error in spec file 17202 on sh4 17203 __________________________________________________________________ 17204 17205 GCC 3.3.3 17206 17207 Minor features 17208 17209 In addition to the bug fixes documented below, this release contains 17210 few minor features such as: 17211 * Support for --with-sysroot 17212 * Support for automatic detection of executable stacks 17213 * Support for SSE3 instructions 17214 * Support for thread local storage debugging under GDB on S390 17215 17216 Bug Fixes 17217 17218 This section lists the problem reports (PRs) from GCC's bug tracker 17219 that are known to be fixed in the 3.3.3 release. This list might not be 17220 complete (that is, it is possible that some PRs that have been fixed 17221 are not listed here). 17222 17223 Bootstrap failures and issues 17224 17225 * [416]11890 Building cross gcc-3.3.1 for sparc-sun-solaris2.6 fails 17226 * [417]12399 boehm-gc fails (when building a cross compiler): libtool 17227 unable to infer tagged configuration 17228 * [418]13068 mklibgcc.in doesn't handle multi-level multilib 17229 subdirectories properly 17230 17231 Internal compiler errors (multi-platform) 17232 17233 * [419]10060 ICE (stack overflow) on huge file (300k lines) due to 17234 recursive behaviour of copy_rtx_if_shared, in emit_rtl.c 17235 * [420]10555 (c++) ICE on undefined template argument 17236 * [421]10706 (c++) ICE in mangle_class_name_for_template 17237 * [422]11496 (fortran) error in flow_loops_find when -funroll-loops 17238 active 17239 * [423]11741 ICE in pre_insert_copy_insn, in gcse.c 17240 * [424]12440 GCC crashes during compilation of quicktime4linux 2.0.0 17241 * [425]12632 (fortran) -fbounds-check ICE 17242 * [426]12712 (c++) ICE on short legit C++ code fragment with gcc 17243 3.3.2 17244 * [427]12726 (c++) ICE (segfault) on trivial code 17245 * [428]12890 (c++) ICE on compilation of class with throwing method 17246 * [429]12900 (c++) ICE in rtl_verify_flow_info_1 17247 * [430]13060 (fortran) ICE in fixup_var_refs_1, in function.c on 17248 correct code with -O2 -fno-force-mem 17249 * [431]13289 (c++) ICE in regenerate_decl_from_template on recursive 17250 template 17251 * [432]13318 ICE: floating point exception in the loop optimizer 17252 * [433]13392 (c++) ICE in convert_from_eh_region_ranges_1, in 17253 except.c 17254 * [434]13574 (c++) invalid array default initializer in class lets 17255 gcc consume all memory and die 17256 * [435]13475 ICE on SIMD variables with partial value initialization 17257 * [436]13797 (c++) ICE on invalid template parameter 17258 * [437]13824 (java) gcj SEGV with simple .java program 17259 17260 C and optimization bugs 17261 17262 * [438]8776 loop invariants are not removed (most likely) 17263 * [439]10339 [sparc,ppc,ppc64] Invalid optimization: replacing 17264 strncmp by memcmp 17265 * [440]11350 undefined labels with -Os -fPIC 17266 * [441]12826 Optimizer removes reference through volatile pointer 17267 * [442]12500 stabs debug info: void no longer a predefined / builtin 17268 type 17269 * [443]12941 builtin-bitops-1.c miscompilation (latent bug) 17270 * [444]12953 tree inliner bug (in inline_forbidden_p) and fix 17271 * [445]13041 linux-2.6/sound/core/oss/rate.c miscompiled 17272 * [446]13507 spurious printf format warning 17273 * [447]13382 Type information for const pointer disappears during 17274 optimization. 17275 * [448]13394 noreturn attribute ignored on recursive invokation 17276 * [449]13400 Compiled code crashes storing to read-only location 17277 * [450]13521 Endless loop in calculate_global_regs_live 17278 17279 C++ compiler and library 17280 17281 Some of the bug fixes in this list were made to implement decisions 17282 that the ISO C++ standards committee has made concerning several defect 17283 reports (DRs). Links in the list below point to detailed discussion of 17284 the relevant defect report. 17285 * [451]2094 unimplemented: use of `ptrmem_cst' in template type 17286 unification 17287 * [452]2294 using declaration confusion 17288 * [453]5050 template instantiation depth exceeds limit: recursion 17289 problem? 17290 * [454]9371 Bad exception handling in 17291 i/ostream::operator>>/<<(streambuf*) 17292 * [455]9546 bad exception handling in ostream members 17293 * [456]10081 basic_ios::_M_cache_locale leaves NULL members in the 17294 face of unknown locales 17295 * [457]10093 [458][DR 61] Setting failbit in exceptions doesn't work 17296 * [459]10095 istream::operator>>(int&) sets ios::badbit when 17297 ios::failbit is set. 17298 * [460]11554 Warning about reordering of initializers doesn't mention 17299 location of constructor 17300 * [461]12297 istream::sentry::sentry() handles eof() incorrectly. 17301 * [462]12352 Exception safety problems in src/localename.cc 17302 * [463]12438 Memory leak in locale::combine() 17303 * [464]12540 Memory leak in locale::locale(const char*) 17304 * [465]12594 DRs [466]60 [TC] and [467]63 [TC] not implemented 17305 * [468]12657 Resolution of [469]DR 292 (WP) still unimplemented 17306 * [470]12696 memory eating infinite loop in diagnostics (error 17307 recovery problem) 17308 * [471]12815 Code compiled with optimization behaves unexpectedly 17309 * [472]12862 Conflicts between typedefs/enums and namespace member 17310 declarations 17311 * [473]12926 Wrong value after assignment in initialize list using 17312 bit-fields 17313 * [474]12967 Resolution of [475]DR 300 [WP] still unimplemented 17314 * [476]12971 Resolution of [477]DR 328 [WP] still unimplemented 17315 * [478]13007 basic_streambuf::pubimbue, imbue wrong 17316 * [479]13009 Implicitly-defined assignment operator writes to wrong 17317 memory 17318 * [480]13057 regparm attribute not applied to destructor 17319 * [481]13070 -Wformat option ignored in g++ 17320 * [482]13081 forward template declarations in <complex> let inlining 17321 fail 17322 * [483]13239 Assertion does not seem to work correctly anymore 17323 * [484]13262 "xxx is private within this context" when initializing a 17324 self-contained template class 17325 * [485]13290 simple typo in concept checking for std::generate_n 17326 * [486]13323 Template code does not compile in presence of typedef 17327 * [487]13369 __verify_grouping (and __add_grouping?) not correct 17328 * [488]13371 infinite loop with packed struct and inlining 17329 * [489]13445 Template argument replacement "dereferences" a typedef 17330 * [490]13461 Fails to access protected-ctor from public constant 17331 * [491]13462 Non-standard-conforming type set::pointer 17332 * [492]13478 gcc uses wrong constructor to initialize a const 17333 reference 17334 * [493]13544 "conflicting types" for enums in different scopes 17335 * [494]13650 string::compare should not (always) use 17336 traits_type::length() 17337 * [495]13683 bogus warning about passing non-PODs through ellipsis 17338 * [496]13688 Derived class is denied access to protected base class 17339 member class 17340 * [497]13774 Member variable cleared in virtual multiple inheritance 17341 class 17342 * [498]13884 Protect sstream.tcc from extern template use 17343 17344 Java compiler and library 17345 17346 * [499]10746 [win32] garbage collection crash in GCJ 17347 17348 Objective-C compiler and library 17349 17350 * [500]11433 Crash due to dereferencing null pointer when querying 17351 protocol 17352 17353 Fortran compiler and library 17354 17355 * [501]12633 logical expression gives incorrect result with 17356 -fugly-logint option 17357 * [502]13037 [gcse-lm] g77 generates incorrect code 17358 * [503]13213 Hex constant problem when compiling with -fugly-logint 17359 and -ftypeless-boz 17360 17361 x86-specific (Intel/AMD) 17362 17363 * [504]4490 ICE with -m128bit-long-double 17364 * [505]12292 [x86_64] ICE: RTL check: expected code `const_int', have 17365 `reg' in make_field_assignment, in combine.c 17366 * [506]12441 ICE: can't find a register to spill 17367 * [507]12943 array static-init failure under -fpic, -fPIC 17368 * [508]13608 Incorrect code with -O3 -ffast-math 17369 17370 PowerPC-specific 17371 17372 * [509]11598 testcase gcc.dg/20020118-1.c fails runtime check of 17373 __attribute__((aligned(16))) 17374 * [510]11793 ICE in extract_insn, in recog.c (const_vector's) 17375 * [511]12467 vmsumubm emitted when vmsummbm appropriate (typo in 17376 altivec.md) 17377 * [512]12537 g++ generates writeable text sections 17378 17379 SPARC-specific 17380 17381 * [513]12496 wrong result for __atomic_add(&value, -1) when using -O0 17382 -m64 17383 * [514]12865 mprotect call to make trampoline executable may fail 17384 * [515]13354 ICE in sparc_emit_set_const32 17385 17386 ARM-specific 17387 17388 * [516]10467 [arm] ICE in pre_insert_copy_insn, 17389 17390 ia64-specific 17391 17392 * [517]11226 ICE passing struct arg with two floats 17393 * [518]11227 ICE for _Complex float, _Complex long double args 17394 * [519]12644 GCC 3.3.2 fails to compile glibc on ia64 17395 * [520]13149 build gcc-3.3.2 1305 error:unrecognizable insn 17396 * Various fixes for libunwind 17397 17398 Alpha-specific 17399 17400 * [521]12654 Incorrect comparison code generated for Alpha 17401 * [522]12965 SEGV+ICE in cc1plus on alpha-linux with -O2 17402 * [523]13031 ICE (unrecognizable insn) when building gnome-libs-1.4.2 17403 17404 HPPA-specific 17405 17406 * [524]11634 [hppa] ICE in verify_local_live_at_start, in flow.c 17407 * [525]12158 [hppa] compilation does not terminate at -O1 17408 17409 S390-specific 17410 17411 * [526]11992 Wrong built-in code for memcmp with length 1<<24: only 17412 (1<<24)-1 possible for CLCL-Instruction 17413 17414 SH-specific 17415 17416 * [527]9365 segfault in gen_far_branch (config/sh/sh.c) 17417 * [528]10392 optimizer generates faulty array indexing 17418 * [529]11322 SH profiler outputs multiple definitions of symbol 17419 * [530]13069 gcc/config/sh/rtems.h broken 17420 * [531]13302 Putting a va_list in a struct causes seg fault 17421 * [532]13585 Incorrect optimization of call to sfunc 17422 * Fix inappropriately exported libgcc functions from the shared 17423 library 17424 17425 Other embedded target specific 17426 17427 * [533]8916 [mcore] unsigned char assign gets hosed. 17428 * [534]11576 [h8300] ICE in change_address_1, in emit-rtl.c 17429 * [535]13122 [h8300] local variable gets corrupted by function call 17430 when -fomit-frame-pointer is given 17431 * [536]13256 [cris] strict_low_part mistreated in delay slots 17432 * [537]13373 [mcore] optimization with -frerun-cse-after-loop 17433 -fexpensive-optimizations produces wrong code on mcore 17434 17435 GNU HURD-specific 17436 17437 * [538]12561 gcc/config/t-gnu needs updating to work with 17438 --with-sysroot 17439 17440 Tru64 Unix specific 17441 17442 * [539]6243 testsuite fails almost all tests due to no libintl in 17443 LD_LIBRARY_PATH during test. 17444 * [540]11397 weak aliases broken on Tru64 UNIX 17445 17446 AIX-specific 17447 17448 * [541]12505 build failure due to defines of uchar in cpphash.h and 17449 sys/types.h 17450 * [542]13150 WEAK symbols not exported by collect2 17451 17452 IRIX-specific 17453 17454 * [543]12666 fixincludes problem on IRIX 6.5.19m 17455 17456 Solaris-specific 17457 17458 * [544]12969 Including sys/byteorder.h breaks configure checks 17459 17460 Testsuite problems (compiler is not affected) 17461 17462 * [545]10819 testsuite creates CR+LF on compiler version lines in 17463 test summary files 17464 * [546]11612 abi_check not finding correct libgcc_s.so.1 17465 17466 Miscellaneous 17467 17468 * [547]13211 using -###, incorrect warnings about unused linker file 17469 are produced 17470 __________________________________________________________________ 17471 17472 GCC 3.3.4 17473 17474 This is the [548]list of problem reports (PRs) from GCC's bug tracking 17475 system that are known to be fixed in the 3.3.4 release. This list might 17476 not be complete (that is, it is possible that some PRs that have been 17477 fixed are not listed here). 17478 __________________________________________________________________ 17479 17480 GCC 3.3.5 17481 17482 This is the [549]list of problem reports (PRs) from GCC's bug tracking 17483 system that are known to be fixed in the 3.3.5 release. This list might 17484 not be complete (that is, it is possible that some PRs that have been 17485 fixed are not listed here). 17486 __________________________________________________________________ 17487 17488 GCC 3.3.6 17489 17490 This is the [550]list of problem reports (PRs) from GCC's bug tracking 17491 system that are known to be fixed in the 3.3.6 release. This list might 17492 not be complete (that is, it is possible that some PRs that have been 17493 fixed are not listed here). 17494 17495 17496 For questions related to the use of GCC, please consult these web 17497 pages and the [551]GCC manuals. If that fails, the 17498 [552]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 17499 web pages and the development of GCC are welcome on our developer 17500 list at [553]gcc (a] gcc.gnu.org. All of [554]our lists have public 17501 archives. 17502 17503 Copyright (C) [555]Free Software Foundation, Inc. Verbatim copying and 17504 distribution of this entire article is permitted in any medium, 17505 provided this notice is preserved. 17506 17507 These pages are [556]maintained by the GCC team. Last modified 17508 2019-11-28[557]. 17509 17510 References 17511 17512 1. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6 17513 2. http://gcc.gnu.org/gcc-3.1/changes.html#obsolete_systems 17514 3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems 17515 4. http://gcc.gnu.org/gcc-3.3/changes.html#nonnull_attribute 17516 5. http://gcc.gnu.org/news/dfa.html 17517 6. http://gcc.gnu.org/c99status.html 17518 7. https://gcc.gnu.org/onlinedocs/gcc-3.3.6/g77/News.html 17519 8. https://gcc.gnu.org/PR10140 17520 9. https://gcc.gnu.org/PR10198 17521 10. https://gcc.gnu.org/PR10338 17522 11. https://gcc.gnu.org/PR3581 17523 12. https://gcc.gnu.org/PR4382 17524 13. https://gcc.gnu.org/PR5533 17525 14. https://gcc.gnu.org/PR6387 17526 15. https://gcc.gnu.org/PR6412 17527 16. https://gcc.gnu.org/PR6620 17528 17. https://gcc.gnu.org/PR6663 17529 18. https://gcc.gnu.org/PR7068 17530 19. https://gcc.gnu.org/PR7083 17531 20. https://gcc.gnu.org/PR7647 17532 21. https://gcc.gnu.org/PR7675 17533 22. 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232. https://gcc.gnu.org/PR11282 17744 233. https://gcc.gnu.org/PR11301 17745 234. https://gcc.gnu.org/PR11308 17746 235. https://gcc.gnu.org/PR11473 17747 236. https://gcc.gnu.org/PR11503 17748 237. https://gcc.gnu.org/PR11513 17749 238. https://gcc.gnu.org/PR11198 17750 239. https://gcc.gnu.org/PR11304 17751 240. https://gcc.gnu.org/PR11381 17752 241. https://gcc.gnu.org/PR11536 17753 242. https://gcc.gnu.org/PR11557 17754 243. https://gcc.gnu.org/PR5897 17755 244. https://gcc.gnu.org/PR11279 17756 245. https://gcc.gnu.org/PR11022 17757 246. https://gcc.gnu.org/PR2330 17758 247. https://gcc.gnu.org/PR5388 17759 248. https://gcc.gnu.org/PR5390 17760 249. https://gcc.gnu.org/PR7877 17761 250. https://gcc.gnu.org/PR9393 17762 251. https://gcc.gnu.org/PR10032 17763 252. https://gcc.gnu.org/PR10468 17764 253. https://gcc.gnu.org/PR10527 17765 254. https://gcc.gnu.org/PR10679 17766 255. https://gcc.gnu.org/PR10682 17767 256. https://gcc.gnu.org/PR10689 17768 257. 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481. https://gcc.gnu.org/PR13070 17993 482. https://gcc.gnu.org/PR13081 17994 483. https://gcc.gnu.org/PR13239 17995 484. https://gcc.gnu.org/PR13262 17996 485. https://gcc.gnu.org/PR13290 17997 486. https://gcc.gnu.org/PR13323 17998 487. https://gcc.gnu.org/PR13369 17999 488. https://gcc.gnu.org/PR13371 18000 489. https://gcc.gnu.org/PR13445 18001 490. https://gcc.gnu.org/PR13461 18002 491. https://gcc.gnu.org/PR13462 18003 492. https://gcc.gnu.org/PR13478 18004 493. https://gcc.gnu.org/PR13544 18005 494. https://gcc.gnu.org/PR13650 18006 495. https://gcc.gnu.org/PR13683 18007 496. https://gcc.gnu.org/PR13688 18008 497. https://gcc.gnu.org/PR13774 18009 498. https://gcc.gnu.org/PR13884 18010 499. https://gcc.gnu.org/PR10746 18011 500. https://gcc.gnu.org/PR11433 18012 501. https://gcc.gnu.org/PR12633 18013 502. https://gcc.gnu.org/PR13037 18014 503. https://gcc.gnu.org/PR13213 18015 504. https://gcc.gnu.org/PR4490 18016 505. https://gcc.gnu.org/PR12292 18017 506. https://gcc.gnu.org/PR12441 18018 507. https://gcc.gnu.org/PR12943 18019 508. https://gcc.gnu.org/PR13608 18020 509. https://gcc.gnu.org/PR11598 18021 510. https://gcc.gnu.org/PR11793 18022 511. https://gcc.gnu.org/PR12467 18023 512. https://gcc.gnu.org/PR12537 18024 513. https://gcc.gnu.org/PR12496 18025 514. https://gcc.gnu.org/PR12865 18026 515. https://gcc.gnu.org/PR13354 18027 516. https://gcc.gnu.org/PR10467 18028 517. https://gcc.gnu.org/PR11226 18029 518. https://gcc.gnu.org/PR11227 18030 519. https://gcc.gnu.org/PR12644 18031 520. https://gcc.gnu.org/PR13149 18032 521. https://gcc.gnu.org/PR12654 18033 522. https://gcc.gnu.org/PR12965 18034 523. https://gcc.gnu.org/PR13031 18035 524. https://gcc.gnu.org/PR11634 18036 525. https://gcc.gnu.org/PR12158 18037 526. https://gcc.gnu.org/PR11992 18038 527. https://gcc.gnu.org/PR9365 18039 528. https://gcc.gnu.org/PR10392 18040 529. https://gcc.gnu.org/PR11322 18041 530. https://gcc.gnu.org/PR13069 18042 531. https://gcc.gnu.org/PR13302 18043 532. https://gcc.gnu.org/PR13585 18044 533. https://gcc.gnu.org/PR8916 18045 534. https://gcc.gnu.org/PR11576 18046 535. https://gcc.gnu.org/PR13122 18047 536. https://gcc.gnu.org/PR13256 18048 537. https://gcc.gnu.org/PR13373 18049 538. https://gcc.gnu.org/PR12561 18050 539. https://gcc.gnu.org/PR6243 18051 540. https://gcc.gnu.org/PR11397 18052 541. https://gcc.gnu.org/PR12505 18053 542. https://gcc.gnu.org/PR13150 18054 543. https://gcc.gnu.org/PR12666 18055 544. https://gcc.gnu.org/PR12969 18056 545. https://gcc.gnu.org/PR10819 18057 546. https://gcc.gnu.org/PR11612 18058 547. https://gcc.gnu.org/PR13211 18059 548. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.4 18060 549. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.5 18061 550. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.6 18062 551. https://gcc.gnu.org/onlinedocs/ 18063 552. mailto:gcc-help (a] gcc.gnu.org 18064 553. mailto:gcc (a] gcc.gnu.org 18065 554. https://gcc.gnu.org/lists.html 18066 555. https://www.fsf.org/ 18067 556. https://gcc.gnu.org/about.html 18068 557. http://validator.w3.org/check/referer 18069 ====================================================================== 18070 http://gcc.gnu.org/gcc-3.2/index.html 18071 18072 GCC 3.2 Release Series 18073 18074 (This release series is no longer supported.) 18075 18076 April 25, 2003 18077 18078 The [1]GNU project and the GCC developers are pleased to announce the 18079 release of GCC 3.2.3. 18080 18081 The purpose of the GCC 3.2 release series is to provide a stable 18082 platform for OS distributors to use building their next releases. A 18083 primary objective was to stabilize the C++ ABI; we believe that the 18084 interface to the compiler and the C++ standard library are now 18085 relatively stable. 18086 18087 Be aware that C++ code compiled by GCC 3.2.x will (in general) not 18088 interoperate with code compiled by GCC 3.1.1 or earlier. 18089 18090 Please refer to our [2]detailed list of news, caveats, and bug-fixes 18091 for further information. 18092 18093 Release History 18094 18095 GCC 3.2.3 18096 April 25, 2003 ([3]changes) 18097 18098 GCC 3.2.2 18099 February 5, 2003 ([4]changes) 18100 18101 GCC 3.2.1 18102 November 19, 2002 ([5]changes) 18103 18104 GCC 3.2 18105 August 14, 2002 ([6]changes) 18106 18107 References and Acknowledgements 18108 18109 GCC used to stand for the GNU C Compiler, but since the compiler 18110 supports several other languages aside from C, it now stands for the 18111 GNU Compiler Collection. 18112 18113 A list of [7]successful builds is updated as new information becomes 18114 available. 18115 18116 The GCC developers would like to thank the numerous people that have 18117 contributed new features, improvements, bug fixes, and other changes as 18118 well as test results to GCC. This [8]amazing group of volunteers is 18119 what makes GCC successful. 18120 18121 For additional information about GCC please refer to the [9]GCC project 18122 web site or contact the [10]GCC development mailing list. 18123 18124 To obtain GCC please use [11]our mirror sites, or our CVS server. 18125 18126 18127 For questions related to the use of GCC, please consult these web 18128 pages and the [12]GCC manuals. If that fails, the 18129 [13]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 18130 web pages and the development of GCC are welcome on our developer 18131 list at [14]gcc (a] gcc.gnu.org. All of [15]our lists have public 18132 archives. 18133 18134 Copyright (C) [16]Free Software Foundation, Inc. Verbatim copying and 18135 distribution of this entire article is permitted in any medium, 18136 provided this notice is preserved. 18137 18138 These pages are [17]maintained by the GCC team. Last modified 18139 2019-11-28[18]. 18140 18141 References 18142 18143 1. http://www.gnu.org/ 18144 2. http://gcc.gnu.org/gcc-3.2/changes.html 18145 3. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 18146 4. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.2 18147 5. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.1 18148 6. http://gcc.gnu.org/gcc-3.2/changes.html#3.2 18149 7. http://gcc.gnu.org/gcc-3.2/buildstat.html 18150 8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 18151 9. http://gcc.gnu.org/index.html 18152 10. mailto:gcc (a] gcc.gnu.org 18153 11. http://gcc.gnu.org/mirrors.html 18154 12. https://gcc.gnu.org/onlinedocs/ 18155 13. mailto:gcc-help (a] gcc.gnu.org 18156 14. mailto:gcc (a] gcc.gnu.org 18157 15. https://gcc.gnu.org/lists.html 18158 16. https://www.fsf.org/ 18159 17. https://gcc.gnu.org/about.html 18160 18. http://validator.w3.org/check/referer 18161 ====================================================================== 18162 http://gcc.gnu.org/gcc-3.2/changes.html 18163 18164 GCC 3.2 Release Series 18165 Changes, New Features, and Fixes 18166 18167 The latest release in the 3.2 release series is [1]GCC 3.2.3. 18168 18169 Caveats and New Features 18170 18171 Caveats 18172 18173 * The C++ compiler does not correctly zero-initialize 18174 pointers-to-data members. You must explicitly initialize them. For 18175 example: int S::*m(0); will work, but depending on 18176 default-initialization to zero will not work. This bug cannot be 18177 fixed in GCC 3.2 without inducing unacceptable risks. It will be 18178 fixed in GCC 3.3. 18179 * This GCC release is based on the GCC 3.1 sourcebase, and thus has 18180 all the [2]changes in the GCC 3.1 series. In addition, GCC 3.2 has 18181 a number of C++ ABI fixes which make its C++ compiler generate 18182 binary code which is incompatible with the C++ compilers found in 18183 earlier GCC releases, including GCC 3.1 and GCC 3.1.1. 18184 18185 Frontend Enhancements 18186 18187 C/C++/Objective-C 18188 18189 * The method of constructing the list of directories to be searched 18190 for header files has been revised. If a directory named by a -I 18191 option is a standard system include directory, the option is 18192 ignored to ensure that the default search order for system 18193 directories and the special treatment of system header files are 18194 not defeated. 18195 * The C and Objective-C compilers no longer accept the "Naming Types" 18196 extension (typedef foo = bar); it was already unavailable in C++. 18197 Code which uses it will need to be changed to use the "typeof" 18198 extension instead: typedef typeof(bar) foo. (We have removed this 18199 extension without a period of deprecation because it has caused the 18200 compiler to crash since version 3.0 and no one noticed until very 18201 recently. Thus we conclude it is not in widespread use.) 18202 18203 C++ 18204 18205 * GCC 3.2 fixed serveral differences between the C++ ABI implemented 18206 in GCC and the multi-vendor standard, but more have been found 18207 since the release. 3.2.1 adds a new warning, -Wabi, to warn about 18208 code which is affected by these bugs. We will fix these bugs in 18209 some future release, once we are confident that all have been 18210 found; until then, it is our intention to make changes to the ABI 18211 only if they are necessary for correct compilation of C++, as 18212 opposed to conformance to the ABI documents. 18213 * For details on how to build an ABI compliant compiler for GNU/Linux 18214 systems, check the [3]common C++ ABI page. 18215 18216 New Targets and Target Specific Improvements 18217 18218 IA-32 18219 18220 * Fixed a number of bugs in SSE and MMX intrinsics. 18221 * Fixed common compiler crashes with SSE instruction set enabled 18222 (implied by -march=pentium3, pentium4, athlon-xp) 18223 * __m128 and __m128i is not 128bit aligned when used in structures. 18224 18225 x86-64 18226 18227 * A bug whereby the compiler could generate bad code for bzero has 18228 been fixed. 18229 * ABI fixes (implying ABI incompatibilities with previous version in 18230 some corner cases) 18231 * Fixed prefetch code generation 18232 __________________________________________________________________ 18233 18234 GCC 3.2.3 18235 18236 3.2.3 is a bug fix release only; there are no new features that were 18237 not present in GCC 3.2.2. 18238 18239 Bug Fixes 18240 18241 This section lists the problem reports (PRs) from GCC's bug tracking 18242 system that are known to be fixed in the 3.2.3 release. This list might 18243 not be complete (that is, it is possible that some PRs that have been 18244 fixed are not listed here), and some of the titles have been changed to 18245 make them more clear. 18246 18247 Internal Compiler Errors (multi-platform) 18248 18249 * [4]3782: (c++) -quiet -fstats produces a segmentation fault in 18250 cc1plus 18251 * [5]6440: (c++) template specializations cause ICE 18252 * [6]7050: (c++) ICE on: (i ? get_string() : throw) 18253 * [7]7741: ICE on conflicting types (make_decl_rtl in varasm.c) 18254 * [8]7982: (c++) ICE due to infinite recursion (using STL set) 18255 * [9]8068: exceedingly high (infinite) memory usage 18256 * [10]8178: ICE with __builtin_ffs 18257 * [11]8396: ICE in copy_to_mode_reg, in explow.c 18258 * [12]8674: (c++) ICE in cp_expr_size, in cp/cp-lang.c 18259 * [13]9768: ICE when optimizing inline code at -O2 18260 * [14]9798: (c++) Infinite recursion (segfault) in 18261 cp/decl.c:push_using_directive with recursive using directives 18262 * [15]9799: mismatching structure initializer with nested flexible 18263 array member: ICE 18264 * [16]9928: ICE on duplicate enum declaration 18265 * [17]10114: ICE in mem_loc_descriptor, in dwarf2out.c (affects 18266 sparc, alpha) 18267 * [18]10352: ICE in find_reloads_toplev 18268 * [19]10336: ICE with -Wunreachable-code 18269 18270 C/optimizer bugs: 18271 18272 * [20]8224: Incorrect joining of signed and unsigned division 18273 * [21]8613: -O2 produces wrong code with builtin strlen and 18274 postincrements 18275 * [22]8828: gcc reports some code is unreachable when it is not 18276 * [23]9226: GCSE breaking argument passing 18277 * [24]9853: miscompilation of non-constant structure initializer 18278 * [25]9797: C99-style struct initializers are miscompiled 18279 * [26]9967: Some standard C function calls should not be replaced 18280 when optimizing for size 18281 * [27]10116: ce2: invalid merge of join_bb in the context of switch 18282 statements 18283 * [28]10171: wrong code for inlined function 18284 * [29]10175: -Wunreachable-code doesn't work for single lines 18285 18286 C++ compiler and library: 18287 18288 * [30]8316: Confusing diagnostic for code that misuses conversion 18289 operators 18290 * [31]9169: filebuf output fails if codecvt<>::out returns noconv 18291 * [32]9420: incomplete type incorrectly reported 18292 * [33]9459: typeof in return type specification of template not 18293 supported 18294 * [34]9507: filebuf::open handles ios_base::ate incorrectly 18295 * [35]9538: Out-of-bounds memory access in streambuf::sputbackc 18296 * [36]9602: Total confusion about template/friend/virtual/abstract 18297 * [37]9993: destructor not called for local object created within and 18298 returned from infinite loop 18299 * [38]10167: ieee_1003.1-2001 locale specialisations on a glibc-2.3.2 18300 system 18301 18302 Java compiler and library: 18303 18304 * [39]9652: libgcj build fails on irix6.5.1[78] 18305 * [40]10144: gas on solaris complains about bad .stabs lines for 18306 java, native as unaffected 18307 18308 x86-specific (Intel/AMD): 18309 18310 * [41]8746: gcc miscompiles Linux kernel ppa driver on x86 18311 * [42]9888: -mcpu=k6 -Os produces out of range loop instructions 18312 * [43]9638: Cross-build for target i386-elf and i586-pc-linux-gnu 18313 failed 18314 * [44]9954: Cross-build for target i586-pc-linux-gnu (--with-newlib) 18315 failed 18316 18317 SPARC-specific: 18318 18319 * [45]7784: [Sparc] ICE in extract_insn, in recog.c 18320 * [46]7796: sparc extra failure with -m64 on execute/930921-1.c in 18321 unroll.c 18322 * [47]8281: ICE when compiling with -O2 -fPIC for Ultrasparc 18323 * [48]8366: [Sparc] C testsuite failure with -m64 -fpic -O in 18324 execute/loop-2d.c 18325 * [49]8726: gcc -O2 miscompiles Samba 2.2.7 on 32-bit sparc 18326 * [50]9414: Scheduling bug on Ultrasparc 18327 * [51]10067: GCC-3.2.2 outputs invalid asm on sparc64 18328 18329 m68k-specific: 18330 18331 * [52]7248: broken "inclusive or" code 18332 * [53]8343: m68k-elf/rtems ICE at instantiate_virtual_regs_1 18333 18334 PowerPC-specific: 18335 18336 * [54]9732: Wrong code with -O2 -fPIC 18337 * [55]10073: ICE: powerpc cannot split insn 18338 18339 Alpha-specific: 18340 18341 * [56]7702: optimization problem on a DEC alpha under OSF1 18342 * [57]9671: gcc.3.2.2 does not build on a HP Tru64 Unix v5.1B system 18343 18344 HP-specific: 18345 18346 * [58]8694: <string> breaks <ctype.h> on HP-UX 10.20 (DUP: 9275) 18347 * [59]9953: (ada) gcc 3.2.x can't build 3.3-branch ada on HP-UX 10 18348 (missing symbol) 18349 * [60]10271: Floating point args don't get reloaded across function 18350 calls with -O2 18351 18352 MIPS specific: 18353 18354 * [61]6362: mips-irix6 gcc-3.1 C testsuite failure with -mips4 in 18355 compile/920501-4.c 18356 18357 CRIS specific: 18358 18359 * [62]10377: gcc-3.2.2 creates bad assembler code for cris 18360 18361 Miscellaneous and minor bugs: 18362 18363 * [63]6955: collect2 says "core dumped" when there is no core 18364 __________________________________________________________________ 18365 18366 GCC 3.2.2 18367 18368 Beginning with 3.2.2, GCC's Makefile suite supports redirection of make 18369 install by means of the DESTDIR variable. Parts of the GCC tree have 18370 featured that support long before, but now it is available even from 18371 the top level. 18372 18373 Other than that, GCC 3.2.2 is a bug fix release only; there are no new 18374 features that were not present in GCC 3.2.1. 18375 18376 Bug Fixes 18377 18378 On the following i386-based systems GCC 3.2.1 broke the C ABI wrt. 18379 functions returning structures: Cygwin, FreeBSD (GCC 3.2.1 as shipped 18380 with FreeBSD 5.0 does not have this problem), Interix, a.out-based 18381 GNU/Linux and NetBSD, OpenBSD, and Darwin. GCC 3.2.2 reverts this ABI 18382 change, and thus restores ABI-compatibility with previous releases 18383 (except GCC 3.2.1) on these platforms. 18384 18385 This section lists the problem reports (PRs) from GCC's bug tracking 18386 system that are known to be fixed in the 3.2.2 release. This list might 18387 not be complete (that is, it is possible that some PRs that have been 18388 fixed are not listed here) and some of the titles have been changed to 18389 make them more clear. 18390 18391 Internal Compiler Errors (multi-platform) 18392 18393 * [64]5919: (c++) ICE when passing variable array to template 18394 function 18395 * [65]7129: (c++) ICE with min/max assignment operators (<?= and >?=) 18396 * [66]7507: ICE with -O2 when address of called function is a 18397 complicated expression 18398 * [67]7622: ICE with nested inline functions if function's address is 18399 taken 18400 * [68]7681: (fortran) ICE in compensate_edge, in reg-stack.c (also PR 18401 [69]9258) 18402 * [70]8031: (c++) ICE in code comparing typeids and casting from 18403 virtual base 18404 * [71]8275: ICE in simplify_subreg 18405 * [72]8332: (c++) builtin strlen/template interaction causes ICE 18406 * [73]8372: (c++) ICE on explicit call of destructor 18407 * [74]8439: (c, not c++) empty struct causes ICE 18408 * [75]8442: (c++) ICE with nested template classes 18409 * [76]8518: ICE when compiling mplayer ("extern inline" issue) 18410 * [77]8615: (c++) ICE with out-of-range character constant template 18411 argument 18412 * [78]8663: (c++) ICE in cp_expr_size, at cp-lang.c:307 18413 * [79]8799: (c++) ICE: error reporting routines re-entered 18414 * [80]9328: (c++) ICE with typeof(X) for overloaded X 18415 * [81]9465: (preprocessor) cpp -traditional ICE on null bytes 18416 18417 C++ (compiler and library) bugs 18418 18419 * [82]47: scoping in nested classes is broken 18420 * [83]6745: problems with iostream rdbuf() member function 18421 * [84]8214: conversion from const char* const to char* sometimes 18422 accepted illegally 18423 * [85]8493: builtin strlen and overload resolution (same bug as 18424 [86]8332) 18425 * [87]8503: strange behaviour of function types 18426 * [88]8727: compiler confused by inheritance from an anonymous struct 18427 * [89]7445: poor performance of std::locale::classic() in 18428 multi-threaded applications 18429 * [90]8230: mishandling of overflow in vector<T>::resize 18430 * [91]8399: sync_with_stdio(false) breaks unformatted input 18431 * [92]8662: illegal access of private member of unnamed class is 18432 accepted 18433 * [93]8707: "make distclean" fails in libstdc++-v3 directory 18434 * [94]8708: __USE_MALLOC doesn't work 18435 * [95]8790: Use of non-thread-safe strtok in src/localename.cc 18436 * [96]8887: Bug in date formats with --enable-clocale=generic 18437 * [97]9076: Call Frame Instructions are not handled correctly during 18438 unwind operation 18439 * [98]9151: std::setprecision limited to 16 digits when outputting a 18440 double to a stream 18441 * [99]9168: codecvt<char, char, mbstate_t> overwrites output buffers 18442 * [100]9269: libstdc++ headers: explicit specialization of function 18443 must precede its first use 18444 * [101]9322: return value of basic_streambuf<>::getloc affected by 18445 locale::global 18446 * [102]9433: segfault in runtime support for dynamic_cast 18447 18448 C and optimizer bugs 18449 18450 * [103]8032: GCC incorrectly initializes static structs that have 18451 flexible arrays 18452 * [104]8639: simple arithmetic expression broken 18453 * [105]8794: optimization improperly eliminates certain expressions 18454 * [106]8832: traditional "asm volatile" code is illegally optimized 18455 * [107]8988: loop optimizer bug: with -O2, code is generated that 18456 segfaults (found on i386, bug present for all platforms) 18457 * [108]9492: structure copy clobbers subsequent stores to structure 18458 18459 Objective-C bugs 18460 18461 * [109]9267: Objective-C parser won't build with newer bison versions 18462 (e.g. 1.875) 18463 18464 Ada bugs 18465 18466 * [110]8344: Ada build problem due to conflict between gcc/final.o, 18467 gcc/ada/final.o 18468 18469 Preprocessor bugs 18470 18471 * [111]8524: _Pragma within macros is improperly expanded 18472 * [112]8880: __WCHAR_TYPE__ macro incorrectly set to "long int" with 18473 -fshort-wchar 18474 18475 ARM-specific 18476 18477 * [113]9090: arm ICE with >= -O2; regression from gcc-2.95 18478 18479 x86-specific (Intel/AMD) 18480 18481 * [114]8588: ICE in extract_insn, at recog.c:NNNN (shift instruction) 18482 * [115]8599: loop unroll bug with -march=k6-3 18483 * [116]9506: ABI breakage in structure return (affects BSD and 18484 Cygwin, but not GNU/Linux) 18485 18486 FreeBSD 5.0 specific 18487 18488 * [117]9484: GCC 3.2.1 Bootstrap failure on FreeBSD 5.0 18489 18490 RTEMS-specific 18491 18492 * [118]9292: hppa1.1-rtems configurery problems 18493 * [119]9293: [m68k-elf/rtems] config/m68k/t-crtstuff bug 18494 * [120]9295: [mips-rtems] config/mips/rtems.h init/fini issue 18495 * [121]9296: gthr-rtems regression 18496 * [122]9316: powerpc-rtems: extending multilibs 18497 18498 HP-PA specific 18499 18500 * [123]9493: ICE with -O2 when building a simple function 18501 18502 Documentation 18503 18504 * [124]7341: hyperlink to gcov in GCC documentation doesn't work 18505 * [125]8947: Please add a warning about "-malign-double" in docs 18506 * [126]7448, [127]8882: typo cleanups 18507 __________________________________________________________________ 18508 18509 GCC 3.2.1 18510 18511 3.2.1 adds a new warning, -Wabi. This option warns when GNU C++ 18512 generates code that is known not to be binary-compatible with the 18513 vendor-neutral ia32/ia64 ABI. Please consult the GCC manual, included 18514 in the distribution, for details. 18515 18516 This release also removes an old GCC extension, "naming types", and the 18517 documentation now directs users to use a different GCC extension, 18518 __typeof__, instead. The feature had evidently been broken for a while. 18519 18520 Otherwise, 3.2.1 is a bug fix release only; other than bug fixes and 18521 the new warning there are no new features that were not present in GCC 18522 3.2. 18523 18524 In addition, the previous fix for [128]PR 7445 (poor performance of 18525 std::locale::classic() in multi-threaded applications) was reverted 18526 ("unfixed"), because the "fix" was not thread-safe. 18527 18528 Bug Fixes 18529 18530 This section lists the problem reports (PRs) from GCC's bug tracking 18531 system that are known to be fixed in the 3.2.1 release. This list might 18532 not be complete (that is, it is possible that some PRs that have been 18533 fixed are not listed here). As you can see, the number of bug fixes is 18534 quite large, so it is strongly recommended that users of earlier GCC 18535 3.x releases upgrade to GCC 3.2.1. 18536 18537 Internal Compiler Errors (multi-platform) 18538 18539 * [129]2521: (c++) ICE in build_ptrmemfunc, in cp/typeck.c 18540 * [130]5661: (c++) ICE instantiating template on array of unknown 18541 size (bad code) 18542 * [131]6419: (c++) ICE in make_decl_rtl for "longest" attribute on 18543 64-bit platforms 18544 * [132]6994: (c++) ICE in find_function_data 18545 * [133]7150: preprocessor: GCC -dM -E gives an ICE 18546 * [134]7160: ICE when optimizing branches without a return value 18547 * [135]7228: (c++) ICE when using member template and template 18548 function 18549 * [136]7266: (c++) ICE with -pedantic on missing typename 18550 * [137]7353: ICE from use of "Naming Types" extension, see above 18551 * [138]7411: ICE in instantiate_virtual_regs_1, in function.c 18552 * [139]7478: (c++) ICE on static_cast inside template 18553 * [140]7526: preprocessor core dump when _Pragma implies #pragma 18554 dependency 18555 * [141]7721: (c++) ICE on simple (but incorrect) template ([142]7803 18556 is a duplicate) 18557 * [143]7754: (c++) ICE on union with template parameter 18558 * [144]7788: (c++) redeclaring a definition as an incomplete class 18559 causes ICE 18560 * [145]8031: (c++) ICE in comptypes, in cp/typeck.c 18561 * [146]8055: preprocessor dies with SIG11 when building FreeBSD 18562 kernel 18563 * [147]8067: (c++) ICE due to mishandling of __FUNCTION__ and related 18564 variables 18565 * [148]8134: (c++) ICE in force_store_init_value on legal code 18566 * [149]8149: (c++) ICE on incomplete type 18567 * [150]8160: (c++) ICE in build_modify_expr, in cp/typeck.c: array 18568 initialization 18569 18570 C++ (compiler and library) bugs 18571 18572 * [151]5607: No pointer adjustment in covariant return types 18573 * [152]6579: Infinite loop with statement expressions in member 18574 initialization 18575 * [153]6803: Default copy constructor bug in GCC 3.1 18576 * [154]7176: g++ confused by friend and static member with same name 18577 * [155]7188: Segfault with template class and recursive (incorrect) 18578 initializer list 18579 * [156]7306: Regression: GCC 3.x fails to compile code with virtual 18580 inheritance if a method has a variable number of arguments 18581 * [157]7461: ctype<char>::classic_table() returns offset array on 18582 Cygwin 18583 * [158]7524: f(const float arg[3]) fails 18584 * [159]7584: Erroneous ambiguous base error on using declaration 18585 * [160]7676: Member template overloading problem 18586 * [161]7679: infinite loop when a right parenthesis is missing 18587 * [162]7811: default locale not taken from environment 18588 * [163]7961: compare( char *) implemented incorrectly in 18589 basic_string<> 18590 * [164]8071: basic_ostream::operator<<(streambuf*) loops forever if 18591 streambuf::underflow() leaves gptr() NULL (dups: [165]8127, 18592 [166]6745) 18593 * [167]8096: deque::at() throws std::range_error instead of 18594 std::out_of_range 18595 * [168]8127: cout << cin.rdbuf() infinite loop 18596 * [169]8218: Excessively large memory consumed for classes with large 18597 array members 18598 * [170]8287: GCC 3.2: Destructor called for non-constructed local 18599 object 18600 * [171]8347: empty vector range used in string construction causes 18601 core dump 18602 * [172]8348: fail() flag is set in istringstream when eof() flag is 18603 set 18604 * [173]8391: regression: infinite loop in cp/decl2.c(finish_file) 18605 18606 C and optimizer bugs 18607 18608 * [174]6627: -fno-align-functions doesn't seem to disable function 18609 alignment 18610 * [175]6631: life_analysis misoptimizes code to initialize fields of 18611 a structure 18612 * [176]7102: unsigned char division results in floating exception 18613 * [177]7120: Run once loop should *always* be unrolled 18614 (pessimization) 18615 * [178]7209: Bug involving array referencing and ?: operator 18616 * [179]7515: invalid inlining of global function with -O3 18617 * [180]7814: incorrect scheduling for glibc-2.2.92 strcpy test 18618 * [181]8467: bug in sibling call optimization 18619 18620 Preprocessor bugs 18621 18622 * [182]4890: incorrect line markers from the traditional preprocessor 18623 * [183]7357: -M option omits system headers files (making it the same 18624 as -MM) 18625 * [184]7358: Changes to Sun's make Dependencies 18626 * [185]7602: C++ header files found in CPLUS_INCLUDE_PATH treated as 18627 C headers 18628 * [186]7862: Interrupting GCC -MD removes .d file but not .o 18629 * [187]8190: Failed compilation deletes -MD dependency file 18630 * [188]8524: _Pragma within macro is improperly expanded 18631 18632 x86 specific (Intel/AMD) 18633 18634 * [189]5351: (i686-only) function pass-by-value structure copy 18635 corrupts stack ([190]7591 is a duplicate) 18636 * [191]6845, [192]7034, [193]7124, [194]7174: ICE's with 18637 -march=pentium3/pentium2/athlon (these are all the same underlying 18638 bug, in MMX register use) 18639 * [195]7134, [196]7375, [197]7390: ICE with -march=athlon (maybe same 18640 as above?) 18641 * [198]6890: xmmintrin.h, _MM_TRANSPOSE4_PS is broken 18642 * [199]6981: wrong code in 64-bit manipulation on x86 18643 * [200]7242: GCC -mcpu=pentium[23] doesn't define __tune_pentiumpro__ 18644 macro 18645 * [201]7396: ix86: cmpgt_ss, cmpge_ss, cmpngt_ss, and cmpnge_ss SSE 18646 intrinsics are broken 18647 * [202]7630: GCC 3.2 breaks on Mozilla 1.0's JS sources with 18648 -march=pentium4 18649 * [203]7693: Typo in i386 mmintrin.h header 18650 * [204]7723: ICE - Pentium3 sse - GCC 3.2 18651 * [205]7951: ICE on -march=pentium4 -O2 -mfpmath=sse 18652 * [206]8146: (i686 only) gcc 3.2 miscompiles gcc 2.95.3 18653 18654 PowerPC specific 18655 18656 * [207]5967: GCC bug when profiling nested functions on powerpc 18657 * [208]6984: wrong code generated with -O2, -O3, -Os for do-while 18658 loop on PowerPC 18659 * [209]7114: PowerPC: ICE building strcoll.op from glibc-2.2.5 18660 * [210]7130: miscompiled code for GCC-3.1 on 18661 powerpc-unknown-linux-gnu with -funroll-all-loops 18662 * [211]7133: PowerPC ICE: unrecognizable insn 18663 * [212]7380: ICE in extract_insn, at recog.c:2148 18664 * [213]8252: ICE on Altivec code with optimization turned on 18665 * [214]8451: Altivec ICE in GCC 3.2 18666 18667 HP/PA specific 18668 18669 * [215]7250: __ashrdi3 returns wrong value on 32 bit hppa 18670 18671 SPARC specific 18672 18673 * [216]6668: when using --disable-multilib, libgcc_s.so is installed 18674 in the wrong place on sparc-solaris 18675 * [217]7151: ICE when compiling for UltraSPARC 18676 * [218]7335: SPARC: ICE in verify_wide_reg (flow.c:557) with long 18677 double and -O1 18678 * [219]7842: [REGRESSION] SPARC code gen bug 18679 18680 ARM specific 18681 18682 * [220]7856: [arm] invalid offset in constant pool reference 18683 * [221]7967: optimization produces wrong code (ARM) 18684 18685 Alpha specific 18686 18687 * [222]7374: __builtin_fabsl broken on alpha 18688 18689 IBM s390 specific 18690 18691 * [223]7370: ICE in fixup_var_refs_1 on s390x 18692 * [224]7409: loop optimization bug on s390x-linux-gnu 18693 * [225]8232: s390x: ICE when using bcmp with int length argument 18694 18695 SCO specific 18696 18697 * [226]7623: SCO OpenServer build fails with machmode.def: undefined 18698 symbol: BITS_PER_UNIT 18699 18700 m68k/Coldfire specific 18701 18702 * [227]8314: crtbegin, crtend need to be multilib'ed for this 18703 platform 18704 18705 Documentation 18706 18707 * [228]761: Document some undocumented options 18708 * [229]5610: Fix documentation about invoking SSE instructions 18709 (-mfpmath=sse) 18710 * [230]7484: List -Wmissing-declarations as C-only option 18711 * [231]7531: -mcmodel not documented for x86-64 18712 * [232]8120: Update documentation of bad use of ## 18713 __________________________________________________________________ 18714 18715 GCC 3.2 18716 18717 3.2 is a small bug fix release, but there is a change to the 18718 application binary interface (ABI), hence the change to the second part 18719 of the version number. 18720 18721 The main purpose of the 3.2 release is to correct a couple of problems 18722 in the C++ ABI, with the intention of providing a stable interface 18723 going forward. Accordingly, 3.2 is only a small change to 3.1.1. 18724 18725 Bug Fixes 18726 18727 C++ 18728 18729 * [233]7320: g++ 3.2 relocation problem 18730 * [234]7470: vtable: virtual function pointers not in declaration 18731 order 18732 18733 libstdc++ 18734 18735 * [235]6410: Trouble with non-ASCII monetary symbols and wchar_t 18736 * [236]6503, [237]6642, [238]7186: Problems with comparing or 18737 subtracting various types of const and non-const iterators 18738 * [239]7216: ambiguity with basic_iostream::traits_type 18739 * [240]7220: problem with basic_istream::ignore(0,delimiter) 18740 * [241]7222: locale::operator==() doesn't work on std::locale("") 18741 * [242]7286: placement operator delete issue 18742 * [243]7442: cxxabi.h does not match the C++ ABI 18743 * [244]7445: poor performance of std::locale::classic() in 18744 multi-threaded applications 18745 18746 x86-64 specific 18747 18748 * [245]7291: off-by-one in generated inline bzero code for x86-64 18749 18750 18751 For questions related to the use of GCC, please consult these web 18752 pages and the [246]GCC manuals. If that fails, the 18753 [247]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 18754 web pages and the development of GCC are welcome on our developer 18755 list at [248]gcc (a] gcc.gnu.org. All of [249]our lists have public 18756 archives. 18757 18758 Copyright (C) [250]Free Software Foundation, Inc. Verbatim copying and 18759 distribution of this entire article is permitted in any medium, 18760 provided this notice is preserved. 18761 18762 These pages are [251]maintained by the GCC team. Last modified 18763 2019-11-28[252]. 18764 18765 References 18766 18767 1. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3 18768 2. http://gcc.gnu.org/gcc-3.1/changes.html 18769 3. http://gcc.gnu.org/gcc-3.2/c++-abi.html 18770 4. https://gcc.gnu.org/PR3782 18771 5. https://gcc.gnu.org/PR6440 18772 6. https://gcc.gnu.org/PR7050 18773 7. https://gcc.gnu.org/PR7741 18774 8. https://gcc.gnu.org/PR7982 18775 9. https://gcc.gnu.org/PR8068 18776 10. https://gcc.gnu.org/PR8178 18777 11. https://gcc.gnu.org/PR8396 18778 12. https://gcc.gnu.org/PR8674 18779 13. https://gcc.gnu.org/PR9768 18780 14. https://gcc.gnu.org/PR9798 18781 15. https://gcc.gnu.org/PR9799 18782 16. https://gcc.gnu.org/PR9928 18783 17. https://gcc.gnu.org/PR10114 18784 18. https://gcc.gnu.org/PR10352 18785 19. https://gcc.gnu.org/PR10336 18786 20. https://gcc.gnu.org/PR8224 18787 21. https://gcc.gnu.org/PR8613 18788 22. https://gcc.gnu.org/PR8828 18789 23. https://gcc.gnu.org/PR9226 18790 24. https://gcc.gnu.org/PR9853 18791 25. https://gcc.gnu.org/PR9797 18792 26. https://gcc.gnu.org/PR9967 18793 27. https://gcc.gnu.org/PR10116 18794 28. https://gcc.gnu.org/PR10171 18795 29. https://gcc.gnu.org/PR10175 18796 30. https://gcc.gnu.org/PR8316 18797 31. https://gcc.gnu.org/PR9169 18798 32. https://gcc.gnu.org/PR9420 18799 33. https://gcc.gnu.org/PR9459 18800 34. https://gcc.gnu.org/PR9507 18801 35. https://gcc.gnu.org/PR9538 18802 36. https://gcc.gnu.org/PR9602 18803 37. https://gcc.gnu.org/PR9993 18804 38. https://gcc.gnu.org/PR10167 18805 39. https://gcc.gnu.org/PR9652 18806 40. https://gcc.gnu.org/PR10144 18807 41. https://gcc.gnu.org/PR8746 18808 42. https://gcc.gnu.org/PR9888 18809 43. https://gcc.gnu.org/PR9638 18810 44. https://gcc.gnu.org/PR9954 18811 45. https://gcc.gnu.org/PR7784 18812 46. https://gcc.gnu.org/PR7796 18813 47. https://gcc.gnu.org/PR8281 18814 48. https://gcc.gnu.org/PR8366 18815 49. https://gcc.gnu.org/PR8726 18816 50. https://gcc.gnu.org/PR9414 18817 51. https://gcc.gnu.org/PR10067 18818 52. https://gcc.gnu.org/PR7248 18819 53. https://gcc.gnu.org/PR8343 18820 54. https://gcc.gnu.org/PR9732 18821 55. https://gcc.gnu.org/PR10073 18822 56. https://gcc.gnu.org/PR7702 18823 57. https://gcc.gnu.org/PR9671 18824 58. https://gcc.gnu.org/PR8694 18825 59. https://gcc.gnu.org/PR9953 18826 60. https://gcc.gnu.org/PR10271 18827 61. https://gcc.gnu.org/PR6362 18828 62. https://gcc.gnu.org/PR10377 18829 63. https://gcc.gnu.org/PR6955 18830 64. https://gcc.gnu.org/PR5919 18831 65. https://gcc.gnu.org/PR7129 18832 66. https://gcc.gnu.org/PR7507 18833 67. https://gcc.gnu.org/PR7622 18834 68. https://gcc.gnu.org/PR7681 18835 69. https://gcc.gnu.org/PR9528 18836 70. https://gcc.gnu.org/PR8031 18837 71. https://gcc.gnu.org/PR8275 18838 72. https://gcc.gnu.org/PR8332 18839 73. https://gcc.gnu.org/PR8372 18840 74. https://gcc.gnu.org/PR8439 18841 75. https://gcc.gnu.org/PR8442 18842 76. https://gcc.gnu.org/PR8518 18843 77. https://gcc.gnu.org/PR8615 18844 78. 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105. https://gcc.gnu.org/PR8794 18872 106. https://gcc.gnu.org/PR8832 18873 107. https://gcc.gnu.org/PR8988 18874 108. https://gcc.gnu.org/PR9492 18875 109. https://gcc.gnu.org/PR9267 18876 110. https://gcc.gnu.org/PR8344 18877 111. https://gcc.gnu.org/PR8524 18878 112. https://gcc.gnu.org/PR8880 18879 113. https://gcc.gnu.org/PR9090 18880 114. https://gcc.gnu.org/PR8588 18881 115. https://gcc.gnu.org/PR8599 18882 116. https://gcc.gnu.org/PR9506 18883 117. https://gcc.gnu.org/PR9484 18884 118. https://gcc.gnu.org/PR9292 18885 119. https://gcc.gnu.org/PR9293 18886 120. https://gcc.gnu.org/PR9295 18887 121. https://gcc.gnu.org/PR9296 18888 122. https://gcc.gnu.org/PR9316 18889 123. https://gcc.gnu.org/PR9493 18890 124. https://gcc.gnu.org/PR7341 18891 125. https://gcc.gnu.org/PR8947 18892 126. https://gcc.gnu.org/PR7448 18893 127. https://gcc.gnu.org/PR8882 18894 128. https://gcc.gnu.org/PR7445 18895 129. https://gcc.gnu.org/PR2521 18896 130. https://gcc.gnu.org/PR5661 18897 131. 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https://gcc.gnu.org/PR7357 18950 184. https://gcc.gnu.org/PR7358 18951 185. https://gcc.gnu.org/PR7602 18952 186. https://gcc.gnu.org/PR7862 18953 187. https://gcc.gnu.org/PR8190 18954 188. https://gcc.gnu.org/PR8524 18955 189. https://gcc.gnu.org/PR5351 18956 190. https://gcc.gnu.org/PR7591 18957 191. https://gcc.gnu.org/PR6845 18958 192. https://gcc.gnu.org/PR7034 18959 193. https://gcc.gnu.org/PR7124 18960 194. https://gcc.gnu.org/PR7174 18961 195. https://gcc.gnu.org/PR7134 18962 196. https://gcc.gnu.org/PR7375 18963 197. https://gcc.gnu.org/PR7390 18964 198. https://gcc.gnu.org/PR6890 18965 199. https://gcc.gnu.org/PR6981 18966 200. https://gcc.gnu.org/PR7242 18967 201. https://gcc.gnu.org/PR7396 18968 202. https://gcc.gnu.org/PR7630 18969 203. https://gcc.gnu.org/PR7693 18970 204. https://gcc.gnu.org/PR7723 18971 205. https://gcc.gnu.org/PR7951 18972 206. https://gcc.gnu.org/PR8146 18973 207. https://gcc.gnu.org/PR5967 18974 208. https://gcc.gnu.org/PR6984 18975 209. https://gcc.gnu.org/PR7114 18976 210. https://gcc.gnu.org/PR7130 18977 211. https://gcc.gnu.org/PR7133 18978 212. https://gcc.gnu.org/PR7380 18979 213. https://gcc.gnu.org/PR8252 18980 214. https://gcc.gnu.org/PR8451 18981 215. https://gcc.gnu.org/PR7250 18982 216. https://gcc.gnu.org/PR6668 18983 217. https://gcc.gnu.org/PR7151 18984 218. https://gcc.gnu.org/PR7335 18985 219. https://gcc.gnu.org/PR7842 18986 220. https://gcc.gnu.org/PR7856 18987 221. https://gcc.gnu.org/PR7967 18988 222. https://gcc.gnu.org/PR7374 18989 223. https://gcc.gnu.org/PR7370 18990 224. https://gcc.gnu.org/PR7409 18991 225. https://gcc.gnu.org/PR8232 18992 226. https://gcc.gnu.org/PR7623 18993 227. https://gcc.gnu.org/PR8314 18994 228. https://gcc.gnu.org/PR761 18995 229. https://gcc.gnu.org/PR5610 18996 230. https://gcc.gnu.org/PR7484 18997 231. https://gcc.gnu.org/PR7531 18998 232. https://gcc.gnu.org/PR8120 18999 233. https://gcc.gnu.org/PR7320 19000 234. https://gcc.gnu.org/PR7470 19001 235. https://gcc.gnu.org/PR6410 19002 236. https://gcc.gnu.org/PR6503 19003 237. https://gcc.gnu.org/PR6642 19004 238. https://gcc.gnu.org/PR7186 19005 239. https://gcc.gnu.org/PR7216 19006 240. https://gcc.gnu.org/PR7220 19007 241. https://gcc.gnu.org/PR7222 19008 242. https://gcc.gnu.org/PR7286 19009 243. https://gcc.gnu.org/PR7442 19010 244. https://gcc.gnu.org/PR7445 19011 245. https://gcc.gnu.org/PR7291 19012 246. https://gcc.gnu.org/onlinedocs/ 19013 247. mailto:gcc-help (a] gcc.gnu.org 19014 248. mailto:gcc (a] gcc.gnu.org 19015 249. https://gcc.gnu.org/lists.html 19016 250. https://www.fsf.org/ 19017 251. https://gcc.gnu.org/about.html 19018 252. http://validator.w3.org/check/referer 19019 ====================================================================== 19020 http://gcc.gnu.org/gcc-3.1/index.html 19021 19022 GCC 3.1 19023 19024 (This release series is no longer supported.) 19025 19026 July 27, 2002 19027 19028 The [1]GNU project and the GCC developers are pleased to announce the 19029 release of GCC 3.1.1. 19030 19031 The links below still apply to GCC 3.1.1. 19032 19033 May 15, 2002 19034 19035 The [2]GNU project and the GCC developers are pleased to announce the 19036 release of GCC 3.1. 19037 19038 GCC used to stand for the GNU C Compiler, but since the compiler 19039 supports several other languages aside from C, it now stands for the 19040 GNU Compiler Collection. 19041 19042 A list of [3]successful builds is updated as new information becomes 19043 available. 19044 19045 The GCC developers would like to thank the numerous people that have 19046 contributed [4]new features, improvements, bug fixes, and other changes 19047 as well as test results to GCC. This [5]amazing group of volunteers is 19048 what makes GCC successful. 19049 19050 For additional information about GCC please refer to the [6]GCC project 19051 web site or contact the [7]GCC development mailing list. 19052 19053 To obtain GCC please use [8]our mirror sites, or our CVS server. 19054 __________________________________________________________________ 19055 19056 19057 For questions related to the use of GCC, please consult these web 19058 pages and the [9]GCC manuals. If that fails, the 19059 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19060 web pages and the development of GCC are welcome on our developer 19061 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 19062 archives. 19063 19064 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 19065 distribution of this entire article is permitted in any medium, 19066 provided this notice is preserved. 19067 19068 These pages are [14]maintained by the GCC team. Last modified 19069 2019-11-28[15]. 19070 19071 References 19072 19073 1. http://www.gnu.org/ 19074 2. http://www.gnu.org/ 19075 3. http://gcc.gnu.org/gcc-3.1/buildstat.html 19076 4. http://gcc.gnu.org/gcc-3.1/changes.html 19077 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19078 6. http://gcc.gnu.org/index.html 19079 7. mailto:gcc (a] gcc.gnu.org 19080 8. http://gcc.gnu.org/mirrors.html 19081 9. https://gcc.gnu.org/onlinedocs/ 19082 10. mailto:gcc-help (a] gcc.gnu.org 19083 11. mailto:gcc (a] gcc.gnu.org 19084 12. https://gcc.gnu.org/lists.html 19085 13. https://www.fsf.org/ 19086 14. https://gcc.gnu.org/about.html 19087 15. http://validator.w3.org/check/referer 19088 ====================================================================== 19089 http://gcc.gnu.org/gcc-3.1/changes.html 19090 19091 GCC 3.1 Release Series 19092 Changes, New Features, and Fixes 19093 19094 Additional changes in GCC 3.1.1 19095 19096 * A bug related to how structures and unions are returned has been 19097 fixed for powerpc-*-netbsd*. 19098 * An important bug in the implementation of -fprefetch-loop-arrays 19099 has been fixed. Previously the optimization prefetched random 19100 blocks of memory for most targets except for i386. 19101 * The Java compiler now compiles Java programs much faster and also 19102 works with parallel make. 19103 * Nested functions have been fixed for mips*-*-netbsd*. 19104 * Some missing floating point support routines have beed added for 19105 mips*-*-netbsd*. 19106 * This [1]message gives additional information about the bugs fixed 19107 in this release. 19108 19109 Caveats 19110 19111 * The -traditional C compiler option has been deprecated and will be 19112 removed in GCC 3.3. (It remains possible to preprocess non-C code 19113 with the traditional preprocessor.) 19114 * The default debugging format for most ELF platforms (including 19115 GNU/Linux and FreeBSD; notable exception is Solaris) has changed 19116 from stabs to DWARF2. This requires GDB 5.1.1 or later. 19117 19118 General Optimizer Improvements 19119 19120 * Jan Hubicka, SuSE Labs, together with Richard Henderson, Red Hat, 19121 and Andreas Jaeger, SuSE Labs, has contributed [2]infrastructure 19122 for profile driven optimizations. 19123 Options -fprofile-arcs and -fbranch-probabilities can now be used 19124 to improve speed of the generated code by profiling the actual 19125 program behaviour on typical runs. In the absence of profile info 19126 the compiler attempts to guess the profile statically. 19127 * [3]SPEC2000 and SPEC95 benchmark suites are now used daily to 19128 monitor performance of the generated code. 19129 According to the SPECInt2000 results on an AMD Athlon CPU, the code 19130 generated by GCC 3.1 is 6% faster on the average (8.2% faster with 19131 profile feedback) compared to GCC 3.0. The code produced by GCC 3.0 19132 is about 2.1% faster compared to 2.95.3. Tests were done using the 19133 -O2 -march=athlon command-line options. 19134 * Alexandre Oliva, of Red Hat, has generalized the tree inlining 19135 infrastructure developed by CodeSourcery, LLC for the C++ front 19136 end, so that it is now used in the C front end too. Inlining 19137 functions as trees exposes them earlier to the compiler, giving it 19138 more opportunities for optimization. 19139 * Support for data prefetching instructions has been added to the GCC 19140 back end and several targets. A new __builtin_prefetch intrinsic is 19141 available to explicitly insert prefetch instructions and 19142 experimental support for loop array prefetching has been added (see 19143 -fprefetch-loop-array documentation). 19144 * Support for emitting debugging information for macros has been 19145 added for DWARF2. It is activated using -g3. 19146 19147 New Languages and Language specific improvements 19148 19149 C/C++ 19150 19151 * A few more [4]ISO C99 features. 19152 * The preprocessor is 10-50% faster than the preprocessor in GCC 3.0. 19153 * The preprocessor's symbol table has been merged with the symbol 19154 table of the C, C++ and Objective-C front ends. 19155 * The preprocessor consumes less memory than the preprocessor in GCC 19156 3.0, often significantly so. On normal input files, it typically 19157 consumes less memory than pre-3.0 cccp-based GCC, too. 19158 19159 C++ 19160 19161 * -fhonor-std and -fno-honor-std have been removed. -fno-honor-std 19162 was a workaround to allow std compliant code to work with the 19163 non-std compliant libstdc++-v2. libstdc++-v3 is std compliant. 19164 * The C++ ABI has been fixed so that void (A::*)() const is mangled 19165 as "M1AKFvvE", rather than "MK1AFvvE" as before. This change only 19166 affects pointer to cv-qualified member function types. 19167 * The C++ ABI has been changed to correctly handle this code: 19168 struct A { 19169 void operator delete[] (void *, size_t); 19170 }; 19171 19172 struct B : public A { 19173 }; 19174 19175 new B[10]; 19176 19177 The amount of storage allocated for the array will be greater than 19178 it was in 3.0, in order to store the number of elements in the 19179 array, so that the correct size can be passed to operator delete[] 19180 when the array is deleted. Previously, the value passed to operator 19181 delete[] was unpredictable. 19182 This change will only affect code that declares a two-argument 19183 operator delete[] with a second parameter of type size_t in a base 19184 class, and does not override that definition in a derived class. 19185 * The C++ ABI has been changed so that: 19186 struct A { 19187 void operator delete[] (void *, size_t); 19188 void operator delete[] (void *); 19189 }; 19190 19191 does not cause unnecessary storage to be allocated when an array of 19192 A objects is allocated. 19193 This change will only affect code that declares both of these forms 19194 of operator delete[], and declared the two-argument form before the 19195 one-argument form. 19196 * The C++ ABI has been changed so that when a parameter is passed by 19197 value, any cleanup for that parameter is performed in the caller, 19198 as specified by the ia64 C++ ABI, rather than the called function 19199 as before. As a result, classes with a non-trivial destructor but a 19200 trivial copy constructor will be passed and returned by invisible 19201 reference, rather than by bitwise copy as before. 19202 * G++ now supports the "named return value optimization": for code 19203 like 19204 A f () { 19205 A a; 19206 ... 19207 return a; 19208 } 19209 19210 G++ will allocate a in the return value slot, so that the return 19211 becomes a no-op. For this to work, all return statements in the 19212 function must return the same variable. 19213 * Improvements to the C++ library are listed in [5]the libstdc++-v3 19214 FAQ. 19215 19216 Objective-C 19217 19218 * Annoying linker warnings (due to incorrect code being generated) 19219 have been fixed. 19220 * If a class method cannot be found, the compiler no longer issues a 19221 warning if a corresponding instance method exists in the root 19222 class. 19223 * Forward @protocol declarations have been fixed. 19224 * Loading of categories has been fixed in certain situations (GNU run 19225 time only). 19226 * The class lookup in the run-time library has been rewritten so that 19227 class method dispatch is more than twice as fast as it used to be 19228 (GNU run time only). 19229 19230 Java 19231 19232 * libgcj now includes RMI, java.lang.ref.*, javax.naming, and 19233 javax.transaction. 19234 * Property files and other system resources can be compiled into 19235 executables which use libgcj using the new gcj --resource feature. 19236 * libgcj has been ported to more platforms. In particular there is 19237 now a mostly-functional mingw32 (Windows) target port. 19238 * JNI and CNI invocation interfaces were implemented, so gcj-compiled 19239 Java code can now be called from a C/C++ application. 19240 * gcj can now use builtin functions for certain known methods, for 19241 instance Math.cos. 19242 * gcj can now automatically remove redundant array-store checks in 19243 some common cases. 19244 * The --no-store-checks optimization option was added. This can be 19245 used to omit runtime store checks for code which is known not to 19246 throw ArrayStoreException 19247 * The following third party interface standards were added to libgcj: 19248 org.w3c.dom and org.xml.sax. 19249 * java.security has been merged with GNU Classpath. The new package 19250 is now JDK 1.2 compliant, and much more complete. 19251 * A bytecode verifier was added to the libgcj interpreter. 19252 * java.lang.Character was rewritten to comply with the Unicode 3.0 19253 standard, and improve performance. 19254 * Partial support for many more locales was added to libgcj. 19255 * Socket timeouts have been implemented. 19256 * libgcj has been merged into a single shared library. There are no 19257 longer separate shared libraries for the garbage collector and 19258 zlib. 19259 * Several performance improvements were made to gcj and libgcj: 19260 + Hash synchronization (thin locks) 19261 + A special allocation path for finalizer-free objects 19262 + Thread-local allocation 19263 + Parallel GC, and other GC tweaks 19264 19265 Fortran 19266 19267 Fortran improvements are listed in [6]the Fortran documentation. 19268 19269 Ada 19270 19271 [7]AdaCore, has contributed its GNAT Ada 95 front end and associated 19272 tools. The GNAT compiler fully implements the Ada language as defined 19273 by the ISO/IEC 8652 standard. 19274 19275 Please note that the integration of the Ada front end is still work in 19276 progress. 19277 19278 New Targets and Target Specific Improvements 19279 19280 * Hans-Peter Nilsson has contributed a port to MMIX, the CPU 19281 architecture used in new editions of Donald E. Knuth's The Art of 19282 Computer Programming. 19283 * Axis Communications has contributed its port to the CRIS CPU 19284 architecture, used in the ETRAX system-on-a-chip series. 19285 * Alexandre Oliva, of Red Hat, has contributed a port to the SuperH 19286 SH5 64-bit RISC microprocessor architecture, extending the existing 19287 SH port. 19288 * UltraSPARC is fully supported in 64-bit mode. The option -m64 19289 enables it. 19290 * For compatibility with the Sun compiler #pragma redefine_extname 19291 has been implemented on Solaris. 19292 * The x86 back end has had some noticeable work done to it. 19293 + SuSE Labs developers Jan Hubicka, Bo Thorsen and Andreas 19294 Jaeger have contributed a port to the AMD x86-64 architecture. 19295 For more information on x86-64 see http://www.x86-64.org. 19296 + The compiler now supports MMX, 3DNow!, SSE, and SSE2 19297 instructions. Options -mmmx, -m3dnow, -msse, and -msse2 will 19298 enable the respective instruction sets. Intel C++ compatible 19299 MMX/3DNow!/SSE intrinsics are implemented. SSE2 intrinsics 19300 will be added in next major release. 19301 + Following those improvements, targets for Pentium MMX, K6-2, 19302 K6-3, Pentium III, Pentium 4, and Athlon 4 Mobile/XP/MP were 19303 added. Refer to the documentation on -march= and -mcpu= 19304 options for details. 19305 + For those targets that support it, -mfpmath=sse will cause the 19306 compiler to generate SSE/SSE2 instructions for floating point 19307 math instead of x87 instructions. Usually, this will lead to 19308 quicker code -- especially on the Pentium 4. Note that only 19309 scalar floating point instructions are used and GCC does not 19310 exploit SIMD features yet. 19311 + Prefetch support has been added to the Pentium III, Pentium 4, 19312 K6-2, K6-3, and Athlon series. 19313 + Code generated for floating point to integer conversions has 19314 been improved leading to better performance of many 3D 19315 applications. 19316 * The PowerPC back end has added 64-bit PowerPC GNU/Linux support. 19317 * C++ support for AIX has been improved. 19318 * Aldy Hernandez, of Red Hat, Inc, has contributed extensions to the 19319 PowerPC port supporting the AltiVec programming model (SIMD). The 19320 support, though presently useful, is experimental and is expected 19321 to stabilize for 3.2. The support is written to conform to 19322 Motorola's AltiVec specs. See -maltivec. 19323 19324 Obsolete Systems 19325 19326 Support for a number of older systems has been declared obsolete in GCC 19327 3.1. Unless there is activity to revive them, the next release of GCC 19328 will have their sources permanently removed. 19329 19330 All configurations of the following processor architectures have been 19331 declared obsolete: 19332 * MIL-STD-1750A, 1750a-*-* 19333 * AMD A29k, a29k-*-* 19334 * Convex, c*-convex-* 19335 * Clipper, clipper-*-* 19336 * Elxsi, elxsi-*-* 19337 * Intel i860, i860-*-* 19338 * Sun picoJava, pj-*-* and pjl-*-* 19339 * Western Electric 32000, we32k-*-* 19340 19341 Most configurations of the following processor architectures have been 19342 declared obsolete, but we are preserving a few systems which may have 19343 active developers. It is unlikely that the remaining systems will 19344 survive much longer unless we see definite signs of port activity. 19345 * Motorola 88000 except 19346 + Generic a.out, m88k-*-aout* 19347 + Generic SVR4, m88k-*-sysv4 19348 + OpenBSD, m88k-*-openbsd* 19349 * NS32k except 19350 + NetBSD, ns32k-*-netbsd* 19351 + OpenBSD, ns32k-*-openbsd*. 19352 * ROMP except 19353 + OpenBSD, romp-*-openbsd*. 19354 19355 Finally, only some configurations of these processor architectures are 19356 being obsoleted. 19357 * Alpha: 19358 + OSF/1, alpha*-*-osf[123]*. (Digital Unix and Tru64 Unix, aka 19359 alpha*-*-osf[45], are still supported.) 19360 * ARM: 19361 + RISCiX, arm-*-riscix*. 19362 * i386: 19363 + 386BSD, i?86-*-bsd* 19364 + Chorus, i?86-*-chorusos* 19365 + DG/UX, i?86-*-dgux* 19366 + FreeBSD 1.x, i?86-*-freebsd1.* 19367 + IBM AIX, i?86-*-aix* 19368 + ISC UNIX, i?86-*-isc* 19369 + GNU/Linux with pre-BFD linker, i?86-*-linux*oldld* 19370 + NEXTstep, i?86-next-* 19371 + OSF UNIX, i?86-*-osf1* and i?86-*-osfrose* 19372 + RTEMS/coff, i?86-*-rtemscoff* 19373 + RTEMS/go32, i?86-go32-rtems* 19374 + Sequent/BSD, i?86-sequent-bsd* 19375 + Sequent/ptx before version 3, i?86-sequent-ptx[12]* and 19376 i?86-sequent-sysv3* 19377 + SunOS, i?86-*-sunos* 19378 * Motorola 68000: 19379 + Altos, m68[k0]*-altos-* 19380 + Apollo, m68[k0]*-apollo-* 19381 + Apple A/UX, m68[k0]*-apple-* 19382 + Bull, m68[k0]*-bull-* 19383 + Convergent, m68[k0]*-convergent-* 19384 + Generic SVR3, m68[k0]*-*-sysv3* 19385 + ISI, m68[k0]*-isi-* 19386 + LynxOS, m68[k0]*-*-lynxos* 19387 + NEXT, m68[k0]*-next-* 19388 + RTEMS/coff, m68[k0]*-*-rtemscoff* 19389 + Sony, m68[k0]*-sony-* 19390 * MIPS: 19391 + DEC Ultrix, mips-*-ultrix* and mips-dec-* 19392 + Generic BSD, mips-*-bsd* 19393 + Generic System V, mips-*-sysv* 19394 + IRIX before version 5, mips-sgi-irix[1234]* 19395 + RiscOS, mips-*-riscos* 19396 + Sony, mips-sony-* 19397 + Tandem, mips-tandem-* 19398 * SPARC: 19399 + RTEMS/a.out, sparc-*-rtemsaout*. 19400 19401 Documentation improvements 19402 19403 * The old manual ("Using and Porting the GNU Compiler Collection") 19404 has been replaced by a users manual ("Using the GNU Compiler 19405 Collection") and a separate internals reference manual ("GNU 19406 Compiler Collection Internals"). 19407 * More complete and much improved documentation about GCC's internal 19408 representation used by the C and C++ front ends. 19409 * Many cleanups and improvements in general. 19410 19411 19412 For questions related to the use of GCC, please consult these web 19413 pages and the [8]GCC manuals. If that fails, the 19414 [9]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19415 web pages and the development of GCC are welcome on our developer 19416 list at [10]gcc (a] gcc.gnu.org. All of [11]our lists have public 19417 archives. 19418 19419 Copyright (C) [12]Free Software Foundation, Inc. Verbatim copying and 19420 distribution of this entire article is permitted in any medium, 19421 provided this notice is preserved. 19422 19423 These pages are [13]maintained by the GCC team. Last modified 19424 2019-11-28[14]. 19425 19426 References 19427 19428 1. https://gcc.gnu.org/ml/gcc/2002-07/msg01208.html 19429 2. http://gcc.gnu.org/news/profiledriven.html 19430 3. http://gcc.gnu.org/benchmarks/ 19431 4. http://gcc.gnu.org/c99status.html 19432 5. https://gcc.gnu.org/onlinedocs/libstdc++/faq.html 19433 6. https://gcc.gnu.org/onlinedocs/gcc-3.1.1/g77/News.html 19434 7. https://www.adacore.com/ 19435 8. https://gcc.gnu.org/onlinedocs/ 19436 9. mailto:gcc-help (a] gcc.gnu.org 19437 10. mailto:gcc (a] gcc.gnu.org 19438 11. https://gcc.gnu.org/lists.html 19439 12. https://www.fsf.org/ 19440 13. https://gcc.gnu.org/about.html 19441 14. http://validator.w3.org/check/referer 19442 ====================================================================== 19443 http://gcc.gnu.org/gcc-3.0/index.html 19444 19445 GCC 3.0.4 19446 19447 (This release series is no longer supported.) 19448 19449 February 20, 2002 19450 19451 The [1]GNU project and the GCC developers are pleased to announce the 19452 release of GCC 3.0.4, which is a bug-fix release for the GCC 3.0 19453 series. 19454 19455 GCC used to stand for the GNU C Compiler, but since the compiler 19456 supports several other languages aside from C, it now stands for the 19457 GNU Compiler Collection. 19458 19459 GCC 3.0.x has several new optimizations, new targets, new languages and 19460 many other new features, relative to GCC 2.95.x. See the [2]new 19461 features page for a more complete list. 19462 19463 A list of [3]successful builds is updated as new information becomes 19464 available. 19465 19466 The GCC developers would like to thank the numerous people that have 19467 contributed new features, test results, bug fixes, etc to GCC. This 19468 [4]amazing group of volunteers is what makes GCC successful. 19469 19470 And finally, we can't in good conscience fail to mention some 19471 [5]caveats to using GCC 3.0.x. 19472 19473 For additional information about GCC please refer to the [6]GCC project 19474 web site or contact the [7]GCC development mailing list. 19475 19476 To obtain GCC please use [8]our mirror sites, or our CVS server. 19477 __________________________________________________________________ 19478 19479 Previous 3.0.x Releases 19480 19481 December 20, 2001: GCC 3.0.3 has been released. 19482 October 25, 2001: GCC 3.0.2 has been released. 19483 August 20, 2001: GCC 3.0.1 has been released. 19484 June 18, 2001: GCC 3.0 has been released. 19485 19486 19487 For questions related to the use of GCC, please consult these web 19488 pages and the [9]GCC manuals. If that fails, the 19489 [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19490 web pages and the development of GCC are welcome on our developer 19491 list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public 19492 archives. 19493 19494 Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and 19495 distribution of this entire article is permitted in any medium, 19496 provided this notice is preserved. 19497 19498 These pages are [14]maintained by the GCC team. Last modified 19499 2019-11-28[15]. 19500 19501 References 19502 19503 1. http://www.gnu.org/ 19504 2. http://gcc.gnu.org/gcc-3.0/features.html 19505 3. http://gcc.gnu.org/gcc-3.0/buildstat.html 19506 4. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19507 5. http://gcc.gnu.org/gcc-3.0/caveats.html 19508 6. http://gcc.gnu.org/index.html 19509 7. mailto:gcc (a] gcc.gnu.org 19510 8. http://gcc.gnu.org/mirrors.html 19511 9. https://gcc.gnu.org/onlinedocs/ 19512 10. mailto:gcc-help (a] gcc.gnu.org 19513 11. mailto:gcc (a] gcc.gnu.org 19514 12. https://gcc.gnu.org/lists.html 19515 13. https://www.fsf.org/ 19516 14. https://gcc.gnu.org/about.html 19517 15. http://validator.w3.org/check/referer 19518 ====================================================================== 19519 http://gcc.gnu.org/gcc-3.0/features.html 19520 19521 GCC 3.0 New Features 19522 19523 Additional changes in GCC 3.0.4 19524 19525 * GCC 3.0 now supports newer versions of the [1]NetBSD operating 19526 system, which use the ELF object file format, on x86 processors. 19527 * Correct debugging information is generated from functions that have 19528 lines from multiple files (e.g. yacc output). 19529 * A fix for whitespace handling in the -traditional preprocessor, 19530 which can affect Fortran. 19531 * Fixes to the exception handling runtime. 19532 * More fixes for bad code generation in C++. 19533 * A fix for shared library generation under AIX 4.3. 19534 * Documentation updates. 19535 * Port of GCC to Tensilica's Xtensa processor contributed. 19536 * A fix for compiling the PPC Linux kernel (FAT fs wouldn't link). 19537 19538 Additional changes in GCC 3.0.3 19539 19540 * A fix to correct an accidental change to the PowerPC ABI. 19541 * Fixes for bad code generation on a variety of architectures. 19542 * Improvements to the debugging information generated for C++ 19543 classes. 19544 * Fixes for bad code generation in C++. 19545 * A fix to avoid crashes in the C++ demangler. 19546 * A fix to the C++ standard library to avoid buffer overflows. 19547 * Miscellaneous improvements for a variety of architectures. 19548 19549 Additional changes in GCC 3.0.2 19550 19551 * Fixes for bad code generation during loop unrolling. 19552 * Fixes for bad code generation by the sibling call optimization. 19553 * Minor improvements to x86 code generation. 19554 * Implementation of function descriptors in C++ vtables for IA64. 19555 * Numerous minor bug-fixes. 19556 19557 Additional changes in GCC 3.0.1 19558 19559 * C++ fixes for incorrect code-generation. 19560 * Improved cross-compiling support for the C++ standard library. 19561 * Fixes for some embedded targets that worked in GCC 2.95.3, but not 19562 in GCC 3.0. 19563 * Fixes for various exception-handling bugs. 19564 * A port to the S/390 architecture. 19565 19566 General Optimizer Improvements 19567 19568 * [2]Basic block reordering pass. 19569 * New if-conversion pass with support for conditional (predicated) 19570 execution. 19571 * New tail call and sibling call elimination optimizations. 19572 * New register renaming pass. 19573 * New (experimental) [3]static single assignment (SSA) representation 19574 support. 19575 * New dead-code elimination pass implemented using the SSA 19576 representation. 19577 * [4]Global null pointer test elimination. 19578 * [5]Global code hoisting/unification. 19579 * More builtins and optimizations for stdio.h, string.h and old BSD 19580 functions, as well as for ISO C99 functions. 19581 * New builtin __builtin_expect for giving hints to the branch 19582 predictor. 19583 19584 New Languages and Language specific improvements 19585 19586 * The GNU Compiler for the Java(TM) language (GCJ) is now integrated 19587 and supported, including the run-time library containing most 19588 common non-GUI Java classes, a bytecode interpreter, and the Boehm 19589 conservative garbage collector. Many bugs have been fixed. GCJ can 19590 compile Java source or Java bytecodes to either native code or Java 19591 class files, and supports native methods written in either the 19592 standard JNI or the more efficient and convenient CNI. 19593 * Here is a [6]partial list of C++ improvements, both new features 19594 and those no longer supported. 19595 * New C++ ABI. On the IA-64 platform GCC is capable of 19596 inter-operating with other IA-64 compilers. 19597 * The new ABI also significantly reduces the size of symbol and debug 19598 information. 19599 * New C++ support library and many C++ bug fixes, vastly improving 19600 our conformance to the ISO C++ standard. 19601 * New [7]inliner for C++. 19602 * Rewritten C preprocessor, integrated into the C, C++ and Objective 19603 C compilers, with very many improvements including ISO C99 support 19604 and [8]improvements to dependency generation. 19605 * Support for more [9]ISO C99 features. 19606 * Many improvements to support for checking calls to format functions 19607 such as printf and scanf, including support for ISO C99 format 19608 features, extensions from the Single Unix Specification and GNU 19609 libc 2.2, checking of strfmon formats and features to assist in 19610 auditing for format string security bugs. 19611 * New warnings for C code that may have undefined semantics because 19612 of violations of sequence point rules in the C standard (such as a 19613 = a++;, a[n] = b[n++]; and a[i++] = i;), included in -Wall. 19614 * Additional warning option -Wfloat-equal. 19615 * Improvements to -Wtraditional. 19616 * Fortran improvements are listed in [10]the Fortran documentation. 19617 19618 New Targets and Target Specific Improvements 19619 19620 * New x86 back end, generating much improved code. 19621 * Support for a generic i386-elf target contributed. 19622 * New option to emit x86 assembly code using Intel style syntax 19623 (-mintel-syntax). 19624 * HPUX 11 support contributed. 19625 * Improved PowerPC code generation, including scheduled prologue and 19626 epilogue. 19627 * Port of GCC to Intel's IA-64 processor contributed. 19628 * Port of GCC to Motorola's MCore 210 and 340 contributed. 19629 * New unified back-end for Arm, Thumb and StrongArm contributed. 19630 * Port of GCC to Intel's XScale processor contributed. 19631 * Port of GCC to Atmel's AVR microcontrollers contributed. 19632 * Port of GCC to Mitsubishi's D30V processor contributed. 19633 * Port of GCC to Matsushita's AM33 processor (a member of the MN10300 19634 processor family) contributed. 19635 * Port of GCC to Fujitsu's FR30 processor contributed. 19636 * Port of GCC to Motorola's 68HC11 and 68HC12 processors contributed. 19637 * Port of GCC to Sun's picoJava processor core contributed. 19638 19639 Documentation improvements 19640 19641 * Substantially rewritten and improved C preprocessor manual. 19642 * Many improvements to other documentation. 19643 * Manpages for gcc, cpp and gcov are now generated automatically from 19644 the master Texinfo manual, eliminating the problem of manpages 19645 being out of date. (The generated manpages are only extracts from 19646 the full manual, which is provided in Texinfo form, from which 19647 info, HTML, other formats and a printed manual can be generated.) 19648 * Generated info files are included in the release tarballs alongside 19649 their Texinfo sources, avoiding problems on some platforms with 19650 building makeinfo as part of the GCC distribution. 19651 19652 Other significant improvements 19653 19654 * Garbage collection used internally by the compiler for most memory 19655 allocation instead of obstacks. 19656 * Lengauer and Tarjan algorithm used for computing dominators in the 19657 CFG. This algorithm can be significantly faster and more space 19658 efficient than our older algorithm. 19659 * gccbug script provided to assist in submitting bug reports to our 19660 bug tracking system. (Bug reports previously submitted directly to 19661 our mailing lists, for which you received no bug tracking number, 19662 should be submitted again using gccbug if you can reproduce the 19663 problem with GCC 3.0.) 19664 * The internal libgcc library is [11]built as a shared library on 19665 systems that support it. 19666 * Extensive testsuite included with GCC, with many new tests. In 19667 addition to tests for GCC bugs that have been fixed, many tests 19668 have been added for language features, compiler warnings and 19669 builtin functions. 19670 * Additional language-independent warning options -Wpacked, -Wpadded, 19671 -Wunreachable-code and -Wdisabled-optimization. 19672 * Target-independent options -falign-functions, -falign-loops and 19673 -falign-jumps. 19674 19675 Plus a great many bug fixes and almost all the [12]features found in 19676 GCC 2.95. 19677 19678 19679 For questions related to the use of GCC, please consult these web 19680 pages and the [13]GCC manuals. If that fails, the 19681 [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19682 web pages and the development of GCC are welcome on our developer 19683 list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public 19684 archives. 19685 19686 Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and 19687 distribution of this entire article is permitted in any medium, 19688 provided this notice is preserved. 19689 19690 These pages are [18]maintained by the GCC team. Last modified 19691 2019-11-28[19]. 19692 19693 References 19694 19695 1. http://www.netbsd.org/ 19696 2. http://gcc.gnu.org/news/reorder.html 19697 3. http://gcc.gnu.org/news/ssa.html 19698 4. http://gcc.gnu.org/news/null.html 19699 5. http://gcc.gnu.org/news/unify.html 19700 6. http://gcc.gnu.org/gcc-3.0/c++features.html 19701 7. http://gcc.gnu.org/news/inlining.html 19702 8. http://gcc.gnu.org/news/dependencies.html 19703 9. http://gcc.gnu.org/c99status.html 19704 10. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 19705 11. http://gcc.gnu.org/gcc-3.0/libgcc.html 19706 12. http://gcc.gnu.org/gcc-2.95/features.html 19707 13. https://gcc.gnu.org/onlinedocs/ 19708 14. mailto:gcc-help (a] gcc.gnu.org 19709 15. mailto:gcc (a] gcc.gnu.org 19710 16. https://gcc.gnu.org/lists.html 19711 17. https://www.fsf.org/ 19712 18. https://gcc.gnu.org/about.html 19713 19. http://validator.w3.org/check/referer 19714 ====================================================================== 19715 http://gcc.gnu.org/gcc-3.0/caveats.html 19716 19717 GCC 3.0 Caveats 19718 19719 * -fstrict-aliasing is now part of -O2 and higher optimization 19720 levels. This allows the compiler to assume the strictest aliasing 19721 rules applicable to the language being compiled. For C and C++, 19722 this activates optimizations based on the type of expressions. This 19723 optimization may thus break old, non-compliant code. 19724 * Enumerations are now properly promoted to int in function 19725 parameters and function returns. Normally this change is not 19726 visible, but when using -fshort-enums this is an ABI change. 19727 * The undocumented extension that allowed C programs to have a label 19728 at the end of a compound statement has been deprecated and may be 19729 removed in a future version. Programs that now generate a warning 19730 about this may be fixed by adding a null statement (a single 19731 semicolon) after the label. 19732 * The poorly documented extension that allowed string constants in C, 19733 C++ and Objective C to contain unescaped newlines has been 19734 deprecated and may be removed in a future version. Programs using 19735 this extension may be fixed in several ways: the bare newline may 19736 be replaced by \n, or preceded by \n\, or string concatenation may 19737 be used with the bare newline preceded by \n" and " placed at the 19738 start of the next line. 19739 * The Chill compiler is not included in GCC 3.0, because of the lack 19740 of a volunteer to convert it to use garbage collection. 19741 * Certain non-standard iostream methods from earlier versions of 19742 libstdc++ are not included in libstdc++ v3, i.e. filebuf::attach, 19743 ostream::form, and istream::gets. 19744 * The new C++ ABI is not yet fully supported by current (as of 19745 2001-07-01) releases and development versions of GDB, or any 19746 earlier versions. There is a problem setting breakpoints by line 19747 number, and other related issues that have been fixed in GCC 3.0 19748 but not yet handled in GDB: 19749 [1]https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 19750 19751 19752 For questions related to the use of GCC, please consult these web 19753 pages and the [2]GCC manuals. If that fails, the 19754 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19755 web pages and the development of GCC are welcome on our developer 19756 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 19757 19758 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 19759 distribution of this entire article is permitted in any medium, 19760 provided this notice is preserved. 19761 19762 These pages are [7]maintained by the GCC team. Last modified 19763 2019-11-28[8]. 19764 19765 References 19766 19767 1. https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html 19768 2. https://gcc.gnu.org/onlinedocs/ 19769 3. mailto:gcc-help (a] gcc.gnu.org 19770 4. mailto:gcc (a] gcc.gnu.org 19771 5. https://gcc.gnu.org/lists.html 19772 6. https://www.fsf.org/ 19773 7. https://gcc.gnu.org/about.html 19774 8. http://validator.w3.org/check/referer 19775 ====================================================================== 19776 http://gcc.gnu.org/gcc-2.95/index.html 19777 19778 GCC 2.95 19779 19780 (This release series is no longer supported.) 19781 19782 March 16, 2001: The GNU project and the GCC developers are pleased to 19783 announce the release of GCC version 2.95.3. 19784 19785 Release History 19786 19787 GCC 2.95.3 19788 March 16, 2001 19789 19790 GCC 2.95.2 19791 October 27, 1999 19792 19793 GCC 2.95.1 19794 August 19, 1999 19795 19796 GCC 2.95 19797 July 31, 1999. This is the first release of GCC since the April 19798 1999 GCC/EGCS reunification and includes nearly a year's worth 19799 of new development and bugfixes. 19800 19801 References and Acknowledgements 19802 19803 GCC used to stand for the GNU C Compiler, but since the compiler 19804 supports several other languages aside from C, it now stands for the 19805 GNU Compiler Collection. 19806 19807 The whole suite has been extensively [1]regression tested and 19808 [2]package tested. It should be reliable and suitable for widespread 19809 use. 19810 19811 The compiler has several new optimizations, new targets, new languages 19812 and other new features. See the [3]new features page for a more 19813 complete list of new features found in the GCC 2.95 releases. 19814 19815 The sources include installation instructions in both HTML and 19816 plaintext forms in the install directory in the distribution. However, 19817 the most up to date installation instructions and [4]build/test status 19818 are on the web pages. We will update those pages as new information 19819 becomes available. 19820 19821 The GCC developers would like to thank the numerous people that have 19822 contributed new features, test results, bugfixes, etc to GCC. This 19823 [5]amazing group of volunteers is what makes GCC successful. 19824 19825 And finally, we can't in good conscience fail to mention some 19826 [6]caveats to using GCC 2.95. 19827 19828 Download GCC 2.95 from one of our many [7]mirror sites. 19829 19830 For additional information about GCC please see the [8]GCC project web 19831 server or contact the [9]GCC development mailing list. 19832 19833 19834 For questions related to the use of GCC, please consult these web 19835 pages and the [10]GCC manuals. If that fails, the 19836 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 19837 web pages and the development of GCC are welcome on our developer 19838 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 19839 archives. 19840 19841 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 19842 distribution of this entire article is permitted in any medium, 19843 provided this notice is preserved. 19844 19845 These pages are [15]maintained by the GCC team. Last modified 19846 2019-11-28[16]. 19847 19848 References 19849 19850 1. http://gcc.gnu.org/gcc-2.95/regress.html 19851 2. http://gcc.gnu.org/gcc-2.95/othertest.html 19852 3. http://gcc.gnu.org/gcc-2.95/features.html 19853 4. http://gcc.gnu.org/gcc-2.95/buildstat.html 19854 5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 19855 6. http://gcc.gnu.org/gcc-2.95/caveats.html 19856 7. http://gcc.gnu.org/mirrors.html 19857 8. http://gcc.gnu.org/index.html 19858 9. mailto:gcc (a] gcc.gnu.org 19859 10. https://gcc.gnu.org/onlinedocs/ 19860 11. mailto:gcc-help (a] gcc.gnu.org 19861 12. mailto:gcc (a] gcc.gnu.org 19862 13. https://gcc.gnu.org/lists.html 19863 14. https://www.fsf.org/ 19864 15. https://gcc.gnu.org/about.html 19865 16. http://validator.w3.org/check/referer 19866 ====================================================================== 19867 http://gcc.gnu.org/gcc-2.95/features.html 19868 19869 GCC 2.95 New Features 19870 19871 * General Optimizer Improvements: 19872 + [1]Localized register spilling to improve speed and code 19873 density especially on small register class machines. 19874 + [2]Global CSE using lazy code motion algorithms. 19875 + [3]Improved global constant/copy propagation. 19876 + [4]Improved control flow graph analysis and manipulation. 19877 + [5]Local dead store elimination. 19878 + [6]Memory Load hoisting/store sinking in loops. 19879 + [7]Type based alias analysis is enabled by default. Note this 19880 feature will expose bugs in the Linux kernel. Please refer to 19881 the FAQ (as shipped with GCC 2.95) for additional information 19882 on this issue. 19883 + Major revamp of GIV detection, combination and simplification 19884 to improve loop performance. 19885 + Major improvements to register allocation and reloading. 19886 * New Languages and Language specific improvements 19887 + [8]Many C++ improvements. 19888 + [9]Many Fortran improvements. 19889 + [10]Java front-end has been integrated. A [11]runtime library 19890 is available separately. 19891 + [12]ISO C99 support 19892 + [13]Chill front-end and runtime has been integrated. 19893 + Boehm garbage collector support in libobjc. 19894 + More support for various pragmas which appear in vendor 19895 include files 19896 * New Targets and Target Specific Improvements 19897 + [14]SPARC backend rewrite. 19898 + -mschedule=8000 will optimize code for PA8000 class 19899 processors; -mpa-risc-2-0 will generate code for PA2.0 19900 processors 19901 + Various micro-optimizations for the ia32 port. K6 19902 optimizations 19903 + Compiler will attempt to align doubles in the stack on the 19904 ia32 port 19905 + Alpha EV6 support 19906 + PowerPC 750 19907 + RS6000/PowerPC: -mcpu=401 was added as an alias for -mcpu=403. 19908 -mcpu=e603e was added to do -mcpu=603e and -msoft-float. 19909 + c3x, c4x 19910 + HyperSPARC 19911 + SparcLite86x 19912 + sh4 19913 + Support for new systems (OpenBSD, FreeBSD, UWIN, Interix, 19914 arm-linux) 19915 + vxWorks targets include support for vxWorks threads 19916 + StrongARM 110 and ARM9 support added. ARM Scheduling 19917 parameters rewritten. 19918 + Various changes to the MIPS port to avoid assembler macros, 19919 which in turn improves performance 19920 + Various performance improvements to the i960 port. 19921 + Major rewrite of ns32k port 19922 * Other significant improvements 19923 + [15]Ability to dump cfg information and display it using vcg. 19924 + The new faster scheme for fixing vendor header files is 19925 enabled by default. 19926 + Experimental internationalization support. 19927 + multibyte character support 19928 + Some compile-time speedups for pathological problems 19929 + Better support for complex types 19930 * Plus the usual mountain of bugfixes 19931 * Core compiler is based on the gcc2 development tree from Sept 30, 19932 1998, so we have all of the [16]features found in GCC 2.8. 19933 19934 Additional Changes in GCC 2.95.1 19935 19936 * Generic bugfixes and improvements 19937 + Various documentation fixes related to the GCC/EGCS merger. 19938 + Fix memory management bug which could lead to spurious aborts, 19939 core dumps or random parsing errors in the compiler. 19940 + Fix a couple bugs in the dwarf1 and dwarf2 debug record 19941 support. 19942 + Fix infinite loop in the CSE optimizer. 19943 + Avoid undefined behavior in compiler FP emulation code 19944 + Fix install problem when prefix is overridden on the make 19945 install command. 19946 + Fix problem with unwanted installation of assert.h on some 19947 systems. 19948 + Fix problem with finding the wrong assembler in a single tree 19949 build. 19950 + Avoid increasing the known alignment of a register that is 19951 already known to be a pointer. 19952 * Platform specific bugfixes and improvements 19953 + Codegen bugfix for prologue/epilogue for cpu32 target. 19954 + Fix long long code generation bug for the Coldfire target. 19955 + Fix various aborts in the SH compiler. 19956 + Fix bugs in libgcc support library for the SH. 19957 + Fix alpha ev6 code generation bug. 19958 + Fix problems with EXIT_SUCCESS/EXIT_FAILURE redefinitions on 19959 AIX platforms. 19960 + Fix -fpic code generation bug for rs6000/ppc svr4 targets. 19961 + Fix varargs/stdarg code generation bug for rs6000/ppc svr4 19962 targets. 19963 + Fix weak symbol handling for rs6000/ppc svr4 targets. 19964 + Fix various problems with 64bit code generation for the 19965 rs6000/ppc port. 19966 + Fix codegen bug which caused tetex to be mis-compiled on the 19967 x86. 19968 + Fix compiler abort in new cfg code exposed by x86 port. 19969 + Fix out of range array reference in code convert flat 19970 registers to the x87 stacked FP register file. 19971 + Fix minor vxworks configuration bug. 19972 + Fix return type of bsearch for SunOS 4.x. 19973 * Language & Runtime specific fixes. 19974 + The G++ signature extension has been deprecated. It will be 19975 removed in the next major release of G++. Use of signatures 19976 will result in a warning from the compiler. 19977 + Several bugs relating to templates and namespaces were fixed. 19978 + A bug that caused crashes when combining templates with -g on 19979 DWARF1 platforms was fixed. 19980 + Pointers-to-members, virtual functions, and multiple 19981 inheritance should now work together correctly. 19982 + Some code-generation bugs relating to function try blocks were 19983 fixed. 19984 + G++ is a little bit more lenient with certain archaic 19985 constructs than in GCC 2.95. 19986 + Fix to prevent shared library version #s from bring truncated 19987 to 1 digit 19988 + Fix missing std:: in the libstdc++ library. 19989 + Fix stream locking problems in libio. 19990 + Fix problem in java compiler driver. 19991 19992 Additional Changes in GCC 2.95.2 19993 19994 The -fstrict-aliasing is not enabled by default for GCC 2.95.2. While 19995 the optimizations performed by -fstrict-aliasing are valid according to 19996 the C and C++ standards, the optimization have caused some problems, 19997 particularly with old non-conforming code. 19998 19999 The GCC developers are experimenting with ways to warn users about code 20000 which violates the C/C++ standards, but those warnings are not ready 20001 for widespread use at this time. Rather than wait for those warnings 20002 the GCC developers have chosen to disable -fstrict-aliasing by default 20003 for the GCC 2.95.2 release. 20004 20005 We strongly encourage developers to find and fix code which violates 20006 the C/C++ standards as -fstrict-aliasing may be enabled by default in 20007 future releases. Use the option -fstrict-aliasing to re-enable these 20008 optimizations. 20009 * Generic bugfixes and improvements 20010 + Fix incorrectly optimized memory reference in global common 20011 subexpression elimination (GCSE) optimization pass. 20012 + Fix code generation bug in regmove.c in which it could 20013 incorrectly change a "const" value. 20014 + Fix bug in optimization of conditionals involving volatile 20015 memory references. 20016 + Avoid over-allocation of stack space for some procedures. 20017 + Fixed bug in the compiler which caused incorrect optimization 20018 of an obscure series of bit manipulations, shifts and 20019 arithmetic. 20020 + Fixed register allocator bug which caused teTeX to be 20021 mis-compiled on SPARC targets. 20022 + Avoid incorrect optimization of degenerate case statements for 20023 certain targets such as the ARM. 20024 + Fix out of range memory reference in the jump optimizer. 20025 + Avoid dereferencing null pointer in fix-header. 20026 + Fix test for GCC specific features so that it is possible to 20027 bootstrap with gcc-2.6.2 and older versions of GCC. 20028 + Fix typo in scheduler which could potentially cause out of 20029 range memory accesses. 20030 + Avoid incorrect loop reversal which caused incorrect code for 20031 certain loops on PowerPC targets. 20032 + Avoid incorrect optimization of switch statements on certain 20033 targets (for example the ARM). 20034 * Platform specific bugfixes and improvements 20035 + Work around bug in Sun V5.0 compilers which caused bootstrap 20036 comparison failures on SPARC targets. 20037 + Fix SPARC backend bug which caused aborts in final.c. 20038 + Fix sparc-hal-solaris2* configuration fragments. 20039 + Fix bug in sparc block profiling. 20040 + Fix obscure code generation bug for the PARISC targets. 20041 + Define __STDC_EXT__ for HPUX configurations. 20042 + Various POWERPC64 code generation bugfixes. 20043 + Fix abort for PPC targets using ELF (ex GNU/Linux). 20044 + Fix collect2 problems for AIX targets. 20045 + Correct handling of .file directive for PPC targets. 20046 + Fix bug in fix_trunc x86 patterns. 20047 + Fix x86 port to correctly pop the FP stack for functions that 20048 return structures in memory. 20049 + Fix minor bug in strlen x86 pattern. 20050 + Use stabs debugging instead of dwarf1 for x86-solaris targets. 20051 + Fix template repository code to handle leading underscore in 20052 mangled names. 20053 + Fix weak/weak alias support for OpenBSD. 20054 + GNU/Linux for the ARM has C++ compatible include files. 20055 * Language & Runtime specific fixes. 20056 + Fix handling of constructor attribute in the C front-end which 20057 caused problems building the Chill runtime library on some 20058 targets. 20059 + Fix minor problem merging type qualifiers in the C front-end. 20060 + Fix aliasing bug for pointers and references (C/C++). 20061 + Fix incorrect "non-constant initializer bug" when -traditional 20062 or -fwritable-strings is enabled. 20063 + Fix build error for Chill front-end on SunOS. 20064 + Do not complain about duplicate instantiations when using 20065 -frepo (C++). 20066 + Fix array bounds handling in C++ front-end which caused 20067 problems with dwarf debugging information in some 20068 circumstances. 20069 + Fix minor namespace problem. 20070 + Fix problem linking java programs. 20071 20072 Additional Changes in GCC 2.95.3 20073 20074 * Generic bugfixes and improvements 20075 + Fix numerous problems that caused incorrect optimization in 20076 the register reloading code. 20077 + Fix numerous problems that caused incorrect optimization in 20078 the loop optimizer. 20079 + Fix aborts in the functions build_insn_chain and scan_loops 20080 under some circumstances. 20081 + Fix an alias analysis bug. 20082 + Fix an infinite compilation bug in the combiner. 20083 + A few problems with complex number support have been fixed. 20084 + It is no longer possible for gcc to act as a fork bomb when 20085 installed incorrectly. 20086 + The -fpack-struct option should be recognized now. 20087 + Fixed a bug that caused incorrect code to be generated due to 20088 a lost stack adjustment. 20089 * Platform specific bugfixes and improvements 20090 + Support building ARM toolchains hosted on Windows. 20091 + Fix attribute calculations in ARM toolchains. 20092 + arm-linux support has been improved. 20093 + Fix a PIC failure on sparc targets. 20094 + On ix86 targets, the regparm attribute should now work 20095 reliably. 20096 + Several updates for the h8300 port. 20097 + Fix problem building libio with glibc 2.2. 20098 20099 20100 For questions related to the use of GCC, please consult these web 20101 pages and the [17]GCC manuals. If that fails, the 20102 [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20103 web pages and the development of GCC are welcome on our developer 20104 list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public 20105 archives. 20106 20107 Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and 20108 distribution of this entire article is permitted in any medium, 20109 provided this notice is preserved. 20110 20111 These pages are [22]maintained by the GCC team. Last modified 20112 2019-11-28[23]. 20113 20114 References 20115 20116 1. http://gcc.gnu.org/news/spill.html 20117 2. http://gcc.gnu.org/news/lcm.html 20118 3. http://gcc.gnu.org/news/cprop.html 20119 4. http://gcc.gnu.org/news/cfg.html 20120 5. http://gcc.gnu.org/news/dse.html 20121 6. http://gcc.gnu.org/news/hoist.html 20122 7. http://gcc.gnu.org/news/alias.html 20123 8. http://gcc.gnu.org/gcc-2.95/c++features.html 20124 9. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html 20125 10. http://gcc.gnu.org/news/gcj-announce.txt 20126 11. http://gcc.gnu.org/news/javaannounce.html 20127 12. http://gcc.gnu.org/c99status.html 20128 13. http://gcc.gnu.org/news/chill.html 20129 14. http://gcc.gnu.org/news/sparc.html 20130 15. http://gcc.gnu.org/news/egcs-vcg.html 20131 16. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20132 17. https://gcc.gnu.org/onlinedocs/ 20133 18. mailto:gcc-help (a] gcc.gnu.org 20134 19. mailto:gcc (a] gcc.gnu.org 20135 20. https://gcc.gnu.org/lists.html 20136 21. https://www.fsf.org/ 20137 22. https://gcc.gnu.org/about.html 20138 23. http://validator.w3.org/check/referer 20139 ====================================================================== 20140 http://gcc.gnu.org/gcc-2.95/caveats.html 20141 20142 GCC 2.95 Caveats 20143 20144 * GCC 2.95 will issue an error for invalid asm statements that had 20145 been silently accepted by earlier versions of the compiler. This is 20146 particularly noticeable when compiling older versions of the Linux 20147 kernel (2.0.xx). Please refer to the FAQ (as shipped with GCC 2.95) 20148 for more information on this issue. 20149 * GCC 2.95 implements type based alias analysis to disambiguate 20150 memory references. Some programs, particularly the Linux kernel 20151 violate ANSI/ISO aliasing rules and therefore may not operate 20152 correctly when compiled with GCC 2.95. Please refer to the FAQ (as 20153 shipped with GCC 2.95) for more information on this issue. 20154 * GCC 2.95 has a known bug in its handling of complex variables for 20155 64bit targets. Instead of silently generating incorrect code, GCC 20156 2.95 will issue a fatal error for situations it can not handle. 20157 This primarily affects the Fortran community as Fortran makes more 20158 use of complex variables than C or C++. 20159 * GCC 2.95 has an integrated libstdc++, but does not have an 20160 integrated libg++. Furthermore old libg++ releases will not work 20161 with GCC 2.95. You can retrieve a recent copy of libg++ from the 20162 [1]GCC ftp server. 20163 Note most C++ programs only need libstdc++. 20164 * Exception handling may not work with shared libraries, particularly 20165 on alphas, hppas, rs6000/powerpc and mips based platforms. 20166 Exception handling is known to work on x86 GNU/Linux platforms with 20167 shared libraries. 20168 * In general, GCC 2.95 is more rigorous about rejecting invalid C++ 20169 code or deprecated C++ constructs than G++ 2.7, G++ 2.8, EGCS 1.0, 20170 or EGCS 1.1. As a result it may be necessary to fix C++ code before 20171 it will compile with GCC 2.95. 20172 * G++ is also converting toward the ISO C++ standard; as a result 20173 code which was previously valid (and thus accepted by other 20174 compilers and older versions of g++) may no longer be accepted. The 20175 flag -fpermissive may allow some non-conforming code to compile 20176 with GCC 2.95. 20177 * GCC 2.95 compiled C++ code is not binary compatible with EGCS 20178 1.1.x, EGCS 1.0.x or GCC 2.8.x. 20179 * GCC 2.95 does not have changes from the GCC 2.8 tree that were made 20180 between Sept 30, 1998 and April 30, 1999 (the official end of the 20181 GCC 2.8 project). Future GCC releases will include all the changes 20182 from the defunct GCC 2.8 sources. 20183 20184 20185 For questions related to the use of GCC, please consult these web 20186 pages and the [2]GCC manuals. If that fails, the 20187 [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20188 web pages and the development of GCC are welcome on our developer 20189 list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives. 20190 20191 Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and 20192 distribution of this entire article is permitted in any medium, 20193 provided this notice is preserved. 20194 20195 These pages are [7]maintained by the GCC team. Last modified 20196 2019-11-28[8]. 20197 20198 References 20199 20200 1. ftp://gcc.gnu.org/pub/gcc/infrastructure/libg++-2.8.1.3.tar.gz 20201 2. https://gcc.gnu.org/onlinedocs/ 20202 3. mailto:gcc-help (a] gcc.gnu.org 20203 4. mailto:gcc (a] gcc.gnu.org 20204 5. https://gcc.gnu.org/lists.html 20205 6. https://www.fsf.org/ 20206 7. https://gcc.gnu.org/about.html 20207 8. http://validator.w3.org/check/referer 20208 ====================================================================== 20209 http://gcc.gnu.org/egcs-1.1/index.html 20210 20211 EGCS 1.1 20212 20213 September 3, 1998: We are pleased to announce the release of EGCS 1.1. 20214 December 1, 1998: We are pleased to announce the release of EGCS 1.1.1. 20215 March 15, 1999: We are pleased to announce the release of EGCS 1.1.2. 20216 20217 EGCS is a free software project to further the development of the GNU 20218 compilers using an open development environment. 20219 20220 EGCS 1.1 is a major new release of the EGCS compiler system. It has 20221 been [1]extensively tested and is believed to be stable and suitable 20222 for widespread use. 20223 20224 EGCS 1.1 is based on an June 6, 1998 snapshot of the GCC 2.8 20225 development sources; it contains all of the new features found in GCC 20226 2.8.1 as well as all new development from GCC up to June 6, 1998. 20227 20228 EGCS 1.1 also contains many improvements and features not found in GCC 20229 or in older versions of EGCS: 20230 * Global common subexpression elimination and global constant/copy 20231 propagation (aka [2]gcse) 20232 * Ongoing improvements to the [3]alias analysis support to allow for 20233 better optimizations throughout the compiler. 20234 * Vastly improved [4]C++ compiler and integrated C++ runtime 20235 libraries. 20236 * Fixes for the /tmp symlink race security problems. 20237 * New targets including mips16, arm-thumb and 64 bit PowerPC. 20238 * Improvements to GNU Fortran (g77) compiler and runtime library made 20239 since g77 version 0.5.23. 20240 20241 See the [5]new features page for a more complete list of new features 20242 found in EGCS 1.1 releases. 20243 20244 EGCS 1.1.1 is a minor update to fix several serious problems in EGCS 20245 1.1: 20246 * General improvements and fixes 20247 + Avoid some stack overflows when compiling large functions. 20248 + Avoid incorrect loop invariant code motions. 20249 + Fix some core dumps on Linux kernel code. 20250 + Bring back the imake -Di386 and friends fix from EGCS 1.0.2. 20251 + Fix code generation problem in gcse. 20252 + Various documentation related fixes. 20253 * g++/libstdc++ improvements and fixes 20254 + MT safe EH fix for setjmp/longjmp based exception handling. 20255 + Fix a few bad interactions between optimization and exception 20256 handling. 20257 + Fixes for demangling of template names starting with "__". 20258 + Fix a bug that would fail to run destructors in some cases 20259 with -O2. 20260 + Fix 'new' of classes with virtual bases. 20261 + Fix crash building Qt on the Alpha. 20262 + Fix failure compiling WIFEXITED macro on GNU/Linux. 20263 + Fix some -frepo failures. 20264 * g77 and libf2c improvements and fixes 20265 + Various documentation fixes. 20266 + Avoid compiler crash on RAND intrinsic. 20267 + Fix minor bugs in makefiles exposed by BSD make programs. 20268 + Define _XOPEN_SOURCE for libI77 build to avoid potential 20269 problems on some 64-bit systems. 20270 + Fix problem with implicit endfile on rewind. 20271 + Fix spurious recursive I/O errors. 20272 * platform specific improvements and fixes 20273 + Match all versions of UnixWare7. 20274 + Do not assume x86 SVR4 or UnixWare targets can handle stabs. 20275 + Fix PPC/RS6000 LEGITIMIZE_ADDRESS macro and bug in conversion 20276 from unsigned ints to double precision floats. 20277 + Fix ARM ABI issue with NetBSD. 20278 + Fix a few arm code generation bugs. 20279 + Fixincludes will fix additional broken SCO OpenServer header 20280 files. 20281 + Fix a m68k backend bug which caused invalid offsets in reg+d 20282 addresses. 20283 + Fix problems with 64bit AIX 4.3 support. 20284 + Fix handling of long longs for varargs/stdarg functions on the 20285 ppc. 20286 + Minor fixes to CPP predefines for Windows. 20287 + Fix code generation problems with gpr<->fpr copies for 64bit 20288 ppc. 20289 + Fix a few coldfire code generation bugs. 20290 + Fix some more header file problems on SunOS 4.x. 20291 + Fix assert.h handling for RTEMS. 20292 + Fix Windows handling of TREE_SYMBOL_REFERENCED. 20293 + Fix x86 compiler abort in reg-stack pass. 20294 + Fix cygwin/windows problem with section attributes. 20295 + Fix Alpha code generation problem exposed by SMP Linux 20296 kernels. 20297 + Fix typo in m68k 32->64bit integer conversion. 20298 + Make sure target libraries build with -fPIC for PPC & Alpha 20299 targets. 20300 20301 EGCS 1.1.2 is a minor update to fix several serious problems in EGCS 20302 1.1.1: 20303 * General improvements and fixes 20304 + Fix bug in loop optimizer which caused the SPARC (and 20305 potentially other) ports to segfault. 20306 + Fix infinite recursion in alias analysis and combiner code. 20307 + Fix bug in regclass preferencing. 20308 + Fix incorrect loop reversal which caused incorrect code to be 20309 generated for several targets. 20310 + Fix return value for builtin memcpy. 20311 + Reduce compile time for certain loops which exposed quadratic 20312 behavior in the loop optimizer. 20313 + Fix bug which caused volatile memory to be written multiple 20314 times when only one write was needed/desired. 20315 + Fix compiler abort in caller-save.c 20316 + Fix combiner bug which caused incorrect code generation for 20317 certain division by constant operations. 20318 + Fix incorrect code generation due to a bug in range check 20319 optimizations. 20320 + Fix incorrect code generation due to mis-handling of clobbered 20321 values in CSE. 20322 + Fix compiler abort/segfault due to incorrect register 20323 splitting when unrolling loops. 20324 + Fix code generation involving autoincremented addresses with 20325 ternary operators. 20326 + Work around bug in the scheduler which caused qt to be 20327 mis-compiled on some platforms. 20328 + Fix code generation problems with -fshort-enums. 20329 + Tighten security for temporary files. 20330 + Improve compile time for codes which make heavy use of 20331 overloaded functions. 20332 + Fix multiply defined constructor/destructor symbol problems. 20333 + Avoid setting bogus RPATH environment variable during 20334 bootstrap. 20335 + Avoid GNU-make dependencies in the texinfo subdir. 20336 + Install CPP wrapper script in $(prefix)/bin if --enable-cpp. 20337 --enable-cpp=<dirname> can be used to specify an additional 20338 install directory for the cpp wrapper script. 20339 + Fix CSE bug which caused incorrect label-label refs to appear 20340 on some platforms. 20341 + Avoid linking in EH routines from libgcc if they are not 20342 needed. 20343 + Avoid obscure bug in aliasing code. 20344 + Fix bug in weak symbol handling. 20345 * Platform-specific improvements and fixes 20346 + Fix detection of PPro/PII on Unixware 7. 20347 + Fix compiler segfault when building spec99 and other programs 20348 for SPARC targets. 20349 + Fix code-generation bugs for integer and floating point 20350 conditional move instructions on the PPro/PII. 20351 + Use fixincludes to fix byteorder problems on i?86-*-sysv. 20352 + Fix build failure for the arc port. 20353 + Fix floating point format configuration for i?86-gnu port. 20354 + Fix problems with hppa1.0-hp-hpux10.20 configuration when 20355 threads are enabled. 20356 + Fix coldfire code generation bugs. 20357 + Fix "unrecognized insn" problems for Alpha and PPC ports. 20358 + Fix h8/300 code generation problem with floating point values 20359 in memory. 20360 + Fix unrecognized insn problems for the m68k port. 20361 + Fix namespace-pollution problem for the x86 port. 20362 + Fix problems with old assembler on x86 NeXT systems. 20363 + Fix PIC code-generation problems for the SPARC port. 20364 + Fix minor bug with LONG_CALLS in PowerPC SVR4 support. 20365 + Fix minor ISO namespace violation in Alpha varargs/stdarg 20366 support. 20367 + Fix incorrect "braf" instruction usage for the SH port. 20368 + Fix minor bug in va-sh which prevented its use with -ansi. 20369 + Fix problems recognizing and supporting FreeBSD. 20370 + Handle OpenBSD systems correctly. 20371 + Minor fixincludes fix for Digital UNIX 4.0B. 20372 + Fix problems with ctors/dtors in SCO shared libraries. 20373 + Abort instead of generating incorrect code for PPro/PII 20374 floating point conditional moves. 20375 + Avoid multiply defined symbols on GNU/Linux systems using 20376 libc-5.4.xx. 20377 + Fix abort in alpha compiler. 20378 * Fortran-specific fixes 20379 + Fix the IDate intrinsic (VXT) (in libg2c) so the returned year 20380 is in the documented, non-Y2K-compliant range of 0-99, instead 20381 of being returned as 100 in the year 2000. 20382 + Fix the `Date_and_Time' intrinsic (in libg2c) to return the 20383 milliseconds value properly in Values(8). 20384 + Fix the `LStat' intrinsic (in libg2c) to return device-ID 20385 information properly in SArray(7). 20386 20387 Each release includes installation instructions in both HTML and 20388 plaintext forms (see the INSTALL directory in the toplevel directory of 20389 the distribution). However, we also keep the most up to date 20390 installation instructions and [6]build/test status on our web page. We 20391 will update those pages as new information becomes available. 20392 20393 The EGCS project would like to thank the numerous people that have 20394 contributed new features, test results, bugfixes, etc. This [7]amazing 20395 group of volunteers is what makes EGCS successful. 20396 20397 And finally, we can't in good conscience fail to mention some 20398 [8]caveats to using EGCS 1.1. 20399 20400 Download EGCS from egcs.cygnus.com (USA California). 20401 20402 The EGCS 1.1 release is also available on many mirror sites. 20403 [9]Goto mirror list to find a closer site. 20404 20405 20406 For questions related to the use of GCC, please consult these web 20407 pages and the [10]GCC manuals. If that fails, the 20408 [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20409 web pages and the development of GCC are welcome on our developer 20410 list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public 20411 archives. 20412 20413 Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and 20414 distribution of this entire article is permitted in any medium, 20415 provided this notice is preserved. 20416 20417 These pages are [15]maintained by the GCC team. Last modified 20418 2019-11-28[16]. 20419 20420 References 20421 20422 1. http://gcc.gnu.org/egcs-1.1/egcs-1.1-test.html 20423 2. http://gcc.gnu.org/news/gcse.html 20424 3. http://gcc.gnu.org/news/alias.html 20425 4. http://gcc.gnu.org/egcs-1.1/c++features.html 20426 5. http://gcc.gnu.org/egcs-1.1/features.html 20427 6. http://gcc.gnu.org/egcs-1.1/buildstat.html 20428 7. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html 20429 8. http://gcc.gnu.org/egcs-1.1/caveats.html 20430 9. http://gcc.gnu.org/mirrors.html 20431 10. https://gcc.gnu.org/onlinedocs/ 20432 11. mailto:gcc-help (a] gcc.gnu.org 20433 12. mailto:gcc (a] gcc.gnu.org 20434 13. https://gcc.gnu.org/lists.html 20435 14. https://www.fsf.org/ 20436 15. https://gcc.gnu.org/about.html 20437 16. http://validator.w3.org/check/referer 20438 ====================================================================== 20439 http://gcc.gnu.org/egcs-1.1/features.html 20440 20441 EGCS 1.1 new features 20442 20443 * Integrated GNU Fortran (g77) compiler and runtime library with 20444 improvements, based on g77 version 0.5.23. 20445 * Vast improvements in the C++ compiler; so many they have [1]page of 20446 their own! 20447 * Compiler implements [2]global common subexpression elimination and 20448 global copy/constant propagation. 20449 * More major improvements in the [3]alias analysis code. 20450 * More major improvements in the exception handling code to improve 20451 performance, lower static overhead and provide the infrastructure 20452 for future improvements. 20453 * The infamous /tmp symlink race security problems have been fixed. 20454 * The regmove optimization pass has been nearly completely rewritten 20455 to improve performance of generated code. 20456 * The compiler now recomputes register usage information before local 20457 register allocation. By providing more accurate information to the 20458 priority based allocator, we get better register allocation. 20459 * The register reloading phase of the compiler optimizes spill code 20460 much better than in previous releases. 20461 * Some bad interactions between the register allocator and 20462 instruction scheduler have been fixed, resulting in much better 20463 code for certain programs. Additionally, we have tuned the 20464 scheduler in various ways to improve performance of generated code 20465 for some architectures. 20466 * The compiler's branch shortening algorithms have been significantly 20467 improved to work better on targets which align jump targets. 20468 * The compiler now supports -Os to prefer optimizing for code space 20469 over optimizing for code speed. 20470 * The compiler will now totally eliminate library calls which compute 20471 constant values. This primarily helps targets with no integer 20472 div/mul support and targets without floating point support. 20473 * The compiler now supports an extensive "--help" option. 20474 * cpplib has been greatly improved and may be suitable for limited 20475 use. 20476 * Memory footprint for the compiler has been significantly reduced 20477 for some pathological cases. 20478 * The time to build EGCS has been improved for certain targets 20479 (particularly the alpha and mips platforms). 20480 * Many infrastructure improvements throughout the compiler, plus the 20481 usual mountain of bugfixes and minor improvements. 20482 * Target dependent improvements: 20483 + SPARC port now includes V8 plus and V9 support as well as 20484 performance tuning for Ultra class machines. The SPARC port 20485 now uses the Haifa scheduler. 20486 + Alpha port has been tuned for the EV6 processor and has an 20487 optimized expansion of memcpy/bzero. The Alpha port now uses 20488 the Haifa scheduler. 20489 + RS6000/PowerPC: support for the Power64 architecture and AIX 20490 4.3. The RS6000/PowerPC port now uses the Haifa scheduler. 20491 + x86: Alignment of static store data and jump targets is per 20492 Intel recommendations now. Various improvements throughout the 20493 x86 port to improve performance on Pentium processors 20494 (including improved epilogue sequences for Pentium chips and 20495 backend improvements which should help register allocation on 20496 all x86 variants. Conditional move support has been fixed and 20497 enabled for PPro processors. The x86 port also better supports 20498 64bit operations now. Unixware 7, a System V Release 5 target, 20499 is now supported and SCO OpenServer targets can support GAS. 20500 + MIPS has improved multiply/multiply-add support and now 20501 includes mips16 ISA support. 20502 + M68k has many micro-optimizations and Coldfire fixes. 20503 * Core compiler is based on the GCC development tree from June 9, 20504 1998, so we have all of the [4]features found in GCC 2.8. 20505 20506 20507 For questions related to the use of GCC, please consult these web 20508 pages and the [5]GCC manuals. If that fails, the 20509 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20510 web pages and the development of GCC are welcome on our developer 20511 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 20512 20513 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 20514 distribution of this entire article is permitted in any medium, 20515 provided this notice is preserved. 20516 20517 These pages are [10]maintained by the GCC team. Last modified 20518 2019-11-28[11]. 20519 20520 References 20521 20522 1. http://gcc.gnu.org/egcs-1.1/c++features.html 20523 2. http://gcc.gnu.org/news/gcse.html 20524 3. http://gcc.gnu.org/news/alias.html 20525 4. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20526 5. https://gcc.gnu.org/onlinedocs/ 20527 6. mailto:gcc-help (a] gcc.gnu.org 20528 7. mailto:gcc (a] gcc.gnu.org 20529 8. https://gcc.gnu.org/lists.html 20530 9. https://www.fsf.org/ 20531 10. https://gcc.gnu.org/about.html 20532 11. http://validator.w3.org/check/referer 20533 ====================================================================== 20534 http://gcc.gnu.org/egcs-1.1/caveats.html 20535 20536 EGCS 1.1 Caveats 20537 20538 * EGCS has an integrated libstdc++, but does not have an integrated 20539 libg++. Furthermore old libg++ releases will not work with EGCS; HJ 20540 Lu has made a libg++-2.8.1.2 snapshot available which may work with 20541 EGCS. 20542 Note most C++ programs only need libstdc++. 20543 * Exception handling may not work with shared libraries, particularly 20544 on alphas, hppas, rs6000/powerpc and mips based platforms. 20545 Exception handling is known to work on x86-linux platforms with 20546 shared libraries. 20547 * Some versions of the Linux kernel have bugs which prevent them from 20548 being compiled or from running when compiled by EGCS. See the FAQ 20549 (as shipped with EGCS 1.1) for additional information. 20550 * In general, EGCS is more rigorous about rejecting invalid C++ code 20551 or deprecated C++ constructs than g++-2.7, g++-2.8 or EGCS 1.0. As 20552 a result it may be necessary to fix C++ code before it will compile 20553 with EGCS. 20554 * G++ is also converting toward the ISO C++ standard; as a result 20555 code which was previously valid (and thus accepted by other 20556 compilers and older versions of g++) may no longer be accepted. 20557 * EGCS 1.1 compiled C++ code is not binary compatible with EGCS 1.0.x 20558 or GCC 2.8.x due to changes necessary to support thread safe 20559 exception handling. 20560 20561 20562 For questions related to the use of GCC, please consult these web 20563 pages and the [1]GCC manuals. If that fails, the 20564 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20565 web pages and the development of GCC are welcome on our developer 20566 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 20567 20568 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 20569 distribution of this entire article is permitted in any medium, 20570 provided this notice is preserved. 20571 20572 These pages are [6]maintained by the GCC team. Last modified 20573 2019-11-28[7]. 20574 20575 References 20576 20577 1. https://gcc.gnu.org/onlinedocs/ 20578 2. mailto:gcc-help (a] gcc.gnu.org 20579 3. mailto:gcc (a] gcc.gnu.org 20580 4. https://gcc.gnu.org/lists.html 20581 5. https://www.fsf.org/ 20582 6. https://gcc.gnu.org/about.html 20583 7. http://validator.w3.org/check/referer 20584 ====================================================================== 20585 http://gcc.gnu.org/egcs-1.0/index.html 20586 20587 EGCS 1.0 20588 20589 December 3, 1997: We are pleased to announce the release of EGCS 1.0. 20590 January 6, 1998: We are pleased to announce the release of EGCS 1.0.1. 20591 March 16, 1998: We are pleased to announce the release of EGCS 1.0.2. 20592 May 15, 1998 We are pleased to announce the release of EGCS 1.0.3. 20593 20594 EGCS is a collaborative effort involving several groups of hackers 20595 using an open development model to accelerate development and testing 20596 of GNU compilers and runtime libraries. 20597 20598 An important goal of EGCS is to allow wide scale testing of 20599 experimental features and optimizations; therefore, EGCS contains some 20600 features and optimizations which are still under development. However, 20601 EGCS has been carefully tested and should be comparable in quality to 20602 most GCC releases. 20603 20604 EGCS 1.0 is based on an August 2, 1997 snapshot of the GCC 2.8 20605 development sources; it contains nearly all of the new features found 20606 in GCC 2.8. 20607 20608 EGCS 1.0 also contains many improvements and features not found in GCC 20609 2.7 and even the GCC 2.8 series (which was released after the original 20610 EGCS 1.0 release). 20611 * Integrated C++ runtime libraries, including support for most major 20612 GNU/Linux systems! 20613 * The integrated libstdc++ library includes a verbatim copy of SGI's 20614 STL release. 20615 * Integrated GNU Fortran compiler. 20616 * New instruction scheduler. 20617 * New alias analysis code. 20618 20619 See the [1]new features page for a more complete list of new features. 20620 20621 EGCS 1.0.1 is a minor update to the EGCS 1.0 compiler to fix a few 20622 critical bugs and add support for Red Hat 5.0 Linux. Changes since the 20623 EGCS 1.0 release: 20624 * Add support for Red Hat 5.0 Linux and better support for Linux 20625 systems using glibc2. 20626 Many programs failed to link when compiled with EGCS 1.0 on Red Hat 20627 5.0 or on systems with newer versions of glibc2. EGCS 1.0.1 should 20628 fix these problems. 20629 * Compatibility with both EGCS 1.0 and GCC 2.8 libgcc exception 20630 handling interfaces. 20631 To avoid future compatibility problems, we strongly urge anyone who 20632 is planning on distributing shared libraries that contain C++ code 20633 to upgrade to EGCS 1.0.1 first. 20634 Soon after EGCS 1.0 was released, the GCC developers made some 20635 incompatible changes in libgcc's exception handling interfaces. 20636 These changes were needed to solve problems on some platforms. This 20637 means that GCC 2.8.0, when released, will not be seamlessly 20638 compatible with shared libraries built by EGCS 1.0. The reason is 20639 that the libgcc.a in GCC 2.8.0 will not contain a function needed 20640 by the old interface. 20641 The result of this is that there may be compatibility problems with 20642 shared libraries built by EGCS 1.0 when used with GCC 2.8.0. 20643 With EGCS 1.0.1, generated code uses the new (GCC 2.8.0) interface, 20644 and libgcc.a has the support routines for both the old and the new 20645 interfaces (so EGCS 1.0.1 and EGCS 1.0 code can be freely mixed, 20646 and EGCS 1.0.1 and GCC 2.8.0 code can be freely mixed). 20647 The maintainers of GCC 2.x have decided against including seamless 20648 support for the old interface in 2.8.0, since it was never 20649 "official", so to avoid future compatibility problems we recommend 20650 against distributing any shared libraries built by EGCS 1.0 that 20651 contain C++ code (upgrade to 1.0.1 and use that). 20652 * Various bugfixes in the x86, hppa, mips, and rs6000/ppc back ends. 20653 The x86 changes fix code generation errors exposed when building 20654 glibc2 and the usual GNU/Linux dynamic linker (ld.so). 20655 The hppa change fixes a compiler abort when configured for use with 20656 RTEMS. 20657 The MIPS changes fix problems with the definition of LONG_MAX on 20658 newer systems, allow for command line selection of the target ABI, 20659 and fix one code generation problem. 20660 The rs6000/ppc change fixes some problems with passing structures 20661 to varargs/stdarg functions. 20662 * A few machine independent bugfixes, mostly to fix code generation 20663 errors when building Linux kernels or glibc. 20664 * Fix a few critical exception handling and template bugs in the C++ 20665 compiler. 20666 * Fix Fortran namelist bug on alphas. 20667 * Fix build problems on x86-solaris systems. 20668 20669 EGCS 1.0.2 is a minor update to the EGCS 1.0.1 compiler to fix several 20670 serious problems in EGCS 1.0.1. 20671 * General improvements and fixes 20672 + Memory consumption significantly reduced, especially for 20673 templates and inline functions. 20674 + Fix various problems with glibc2.1. 20675 + Fix loop optimization bug exposed by rs6000/ppc port. 20676 + Fix to avoid potential code generation problems in jump.c. 20677 + Fix some undefined symbol problems in dwarf1 debug support. 20678 * g++/libstdc++ improvements and fixes 20679 + libstdc++ in the EGCS release has been updated and should be 20680 link compatible with libstdc++-2.8. 20681 + Various fixes in libio/libstdc++ to work better on GNU/Linux 20682 systems. 20683 + Fix problems with duplicate symbols on systems that do not 20684 support weak symbols. 20685 + Memory corruption bug and undefined symbols in bastring have 20686 been fixed. 20687 + Various exception handling fixes. 20688 + Fix compiler abort for very long thunk names. 20689 * g77 improvements and fixes 20690 + Fix compiler crash for omitted bound in Fortran CASE 20691 statement. 20692 + Add missing entries to g77 lang-options. 20693 + Fix problem with -fpedantic in the g77 compiler. 20694 + Fix "backspace" problem with g77 on alphas. 20695 + Fix x86 backend problem with Fortran literals and -fpic. 20696 + Fix some of the problems with negative subscripts for g77 on 20697 alphas. 20698 + Fixes for Fortran builds on cygwin32/mingw32. 20699 * platform specific improvements and fixes 20700 + Fix long double problems on x86 (exposed by glibc). 20701 + x86 ports define i386 again to keep imake happy. 20702 + Fix exception handling support on NetBSD ports. 20703 + Several changes to collect2 to fix many problems with AIX. 20704 + Define __ELF__ for GNU/Linux on rs6000. 20705 + Fix -mcall-linux problem on GNU/Linux on rs6000. 20706 + Fix stdarg/vararg problem for GNU/Linux on rs6000. 20707 + Allow autoconf to select a proper install problem on AIX 3.1. 20708 + m68k port support includes -mcpu32 option as well as cpu32 20709 multilibs. 20710 + Fix stdarg bug for irix6. 20711 + Allow EGCS to build on irix5 without the gnu assembler. 20712 + Fix problem with static linking on sco5. 20713 + Fix bootstrap on sco5 with native compiler. 20714 + Fix for abort building newlib on H8 target. 20715 + Fix fixincludes handling of math.h on SunOS. 20716 + Minor fix for Motorola 3300 m68k systems. 20717 20718 EGCS 1.0.3 is a minor update to the EGCS 1.0.2 compiler to fix a few 20719 problems reported by Red Hat for builds of Red Hat 5.1. 20720 * Generic bugfixes: 20721 + Fix a typo in the libio library which resulted in incorrect 20722 behavior of istream::get. 20723 + Fix the Fortran negative array index problem. 20724 + Fix a major problem with the ObjC runtime thread support 20725 exposed by glibc2. 20726 + Reduce memory consumption of the Haifa scheduler. 20727 * Target specific bugfixes: 20728 + Fix one x86 floating point code generation bug exposed by 20729 glibc2 builds. 20730 + Fix one x86 internal compiler error exposed by glibc2 builds. 20731 + Fix profiling bugs on the Alpha. 20732 + Fix ImageMagick & emacs 20.2 build problems on the Alpha. 20733 + Fix rs6000/ppc bug when converting values from integer types 20734 to floating point types. 20735 20736 The EGCS 1.0 releases include installation instructions in both HTML 20737 and plaintext forms (see the INSTALL directory in the toplevel 20738 directory of the distribution). However, we also keep the most up to 20739 date installation instructions and [2]build/test status on our web 20740 page. We will update those pages as new information becomes available. 20741 20742 And, we can't in good conscience fail to mention some [3]caveats to 20743 using EGCS. 20744 20745 Update: Big thanks to Stanford for providing a high speed link for 20746 downloading EGCS (go.cygnus.com)! 20747 20748 Download EGCS from ftp.cygnus.com (USA California) or go.cygnus.com 20749 (USA California -- High speed link provided by Stanford). 20750 20751 The EGCS 1.0 release is also available many mirror sites. 20752 [4]Goto mirror list to find a closer site 20753 20754 We'd like to thank the numerous people that have contributed new 20755 features, test results, bugfixes, etc. Unfortunately, they're far too 20756 numerous to mention by name. 20757 20758 20759 For questions related to the use of GCC, please consult these web 20760 pages and the [5]GCC manuals. If that fails, the 20761 [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20762 web pages and the development of GCC are welcome on our developer 20763 list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives. 20764 20765 Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and 20766 distribution of this entire article is permitted in any medium, 20767 provided this notice is preserved. 20768 20769 These pages are [10]maintained by the GCC team. Last modified 20770 2019-11-28[11]. 20771 20772 References 20773 20774 1. http://gcc.gnu.org/egcs-1.0/features.html 20775 2. http://gcc.gnu.org/egcs-1.0/buildstat.html 20776 3. http://gcc.gnu.org/egcs-1.0/caveats.html 20777 4. http://gcc.gnu.org/mirrors.html 20778 5. https://gcc.gnu.org/onlinedocs/ 20779 6. mailto:gcc-help (a] gcc.gnu.org 20780 7. mailto:gcc (a] gcc.gnu.org 20781 8. https://gcc.gnu.org/lists.html 20782 9. https://www.fsf.org/ 20783 10. https://gcc.gnu.org/about.html 20784 11. http://validator.w3.org/check/referer 20785 ====================================================================== 20786 http://gcc.gnu.org/egcs-1.0/features.html 20787 20788 EGCS 1.0 features 20789 20790 * Core compiler is based on the gcc2 development tree from Aug 2, 20791 1997, so we have most of the [1]features found in GCC 2.8. 20792 * Integrated GNU Fortran compiler based on g77-0.5.22-19970929. 20793 * Vast improvements in the C++ compiler; so many they have [2]page of 20794 their own! 20795 * Integrated C++ runtime libraries, including support for most major 20796 GNU/Linux systems! 20797 * New instruction scheduler from IBM Haifa which includes support for 20798 function wide instruction scheduling as well as superscalar 20799 scheduling. 20800 * Significantly improved alias analysis code. 20801 * Improved register allocation for two address machines. 20802 * Significant code generation improvements for Fortran code on 20803 Alphas. 20804 * Various optimizations from the g77 project as well as improved loop 20805 optimizations. 20806 * Dwarf2 debug format support for some targets. 20807 * egcs libstdc++ includes the SGI STL implementation without changes. 20808 * As a result of these and other changes, egcs libstc++ is not binary 20809 compatible with previous releases of libstdc++. 20810 * Various new ports -- UltraSPARC, Irix6.2 & Irix6.3 support, The SCO 20811 Openserver 5 family (5.0.{0,2,4} and Internet FastStart 1.0 and 20812 1.1), Support for RTEMS on several embedded targets, Support for 20813 arm-linux, Mitsubishi M32R, Hitachi H8/S, Matsushita MN102 and 20814 MN103, NEC V850, Sparclet, Solaris & GNU/Linux on PowerPCs, etc. 20815 * Integrated testsuites for gcc, g++, g77, libstdc++ and libio. 20816 * RS6000/PowerPC ports generate code which can run on all 20817 RS6000/PowerPC variants by default. 20818 * -mcpu= and -march= switches for the x86 port to allow better 20819 control over how the x86 port generates code. 20820 * Includes the template repository patch (aka repo patch); note the 20821 new template code makes repo obsolete for ELF systems using gnu-ld 20822 such as GNU/Linux. 20823 * Plus the usual assortment of bugfixes and improvements. 20824 20825 20826 For questions related to the use of GCC, please consult these web 20827 pages and the [3]GCC manuals. If that fails, the 20828 [4]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20829 web pages and the development of GCC are welcome on our developer 20830 list at [5]gcc (a] gcc.gnu.org. All of [6]our lists have public archives. 20831 20832 Copyright (C) [7]Free Software Foundation, Inc. Verbatim copying and 20833 distribution of this entire article is permitted in any medium, 20834 provided this notice is preserved. 20835 20836 These pages are [8]maintained by the GCC team. Last modified 20837 2019-11-28[9]. 20838 20839 References 20840 20841 1. http://gcc.gnu.org/egcs-1.0/features-2.8.html 20842 2. http://gcc.gnu.org/egcs-1.0/c++features.html 20843 3. https://gcc.gnu.org/onlinedocs/ 20844 4. mailto:gcc-help (a] gcc.gnu.org 20845 5. mailto:gcc (a] gcc.gnu.org 20846 6. https://gcc.gnu.org/lists.html 20847 7. https://www.fsf.org/ 20848 8. https://gcc.gnu.org/about.html 20849 9. http://validator.w3.org/check/referer 20850 ====================================================================== 20851 http://gcc.gnu.org/egcs-1.0/caveats.html 20852 20853 EGCS 1.0 Caveats 20854 20855 * EGCS has an integrated libstdc++, but does not have an integrated 20856 libg++. Furthermore old libg++ releases will not work with egc; HJ 20857 Lu has made a libg++-2.8.1.2 available which may work with EGCS. 20858 Note most C++ programs only need libstdc++. 20859 * Note that using -pedantic or -Wreturn-type can cause an explosion 20860 in the amount of memory needed for template-heavy C++ code, such as 20861 code that uses STL. Also note that -Wall includes -Wreturn-type, so 20862 if you use -Wall you will need to specify -Wno-return-type to turn 20863 it off. 20864 * Exception handling may not work with shared libraries, particularly 20865 on alphas, hppas, and mips based platforms. Exception handling is 20866 known to work on x86-linux platforms with shared libraries. 20867 * Some versions of the Linux kernel have bugs which prevent them from 20868 being compiled or from running when compiled by EGCS. See the FAQ 20869 (as shipped with EGCS 1.0) for additional information. 20870 * In general, EGCS is more rigorous about rejecting invalid C++ code 20871 or deprecated C++ constructs than G++ 2.7. As a result it may be 20872 necessary to fix C++ code before it will compile with EGCS. 20873 * G++ is also aggressively tracking the C++ standard; as a result 20874 code which was previously valid (and thus accepted by other 20875 compilers and older versions of G++) may no longer be accepted. 20876 * EGCS 1.0 may not work with Red Hat Linux 5.0 on all targets. EGCS 20877 1.0.x and later releases should work with Red Hat Linux 5.0. 20878 20879 20880 For questions related to the use of GCC, please consult these web 20881 pages and the [1]GCC manuals. If that fails, the 20882 [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these 20883 web pages and the development of GCC are welcome on our developer 20884 list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives. 20885 20886 Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and 20887 distribution of this entire article is permitted in any medium, 20888 provided this notice is preserved. 20889 20890 These pages are [6]maintained by the GCC team. Last modified 20891 2019-11-28[7]. 20892 20893 References 20894 20895 1. https://gcc.gnu.org/onlinedocs/ 20896 2. mailto:gcc-help (a] gcc.gnu.org 20897 3. mailto:gcc (a] gcc.gnu.org 20898 4. https://gcc.gnu.org/lists.html 20899 5. https://www.fsf.org/ 20900 6. https://gcc.gnu.org/about.html 20901 7. http://validator.w3.org/check/referer 20902 ====================================================================== 20903
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