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NEWS revision 1.12
      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-8/index.html
      9                               GCC 8 Release Series
     10 
     11    Mar 4, 2020
     12 
     13    The [1]GNU project and the GCC developers are pleased to announce the
     14    release of GCC 8.4.
     15 
     16    This release is a bug-fix release, containing fixes for regressions in
     17    GCC 8.3 relative to previous releases of GCC.
     18 
     19 Release History
     20 
     21    GCC 8.4
     22           Mar 4, 2020 ([2]changes, [3]documentation)
     23 
     24    GCC 8.3
     25           Feb 22, 2019 ([4]changes, [5]documentation)
     26 
     27    GCC 8.2
     28           Jul 26, 2018 ([6]changes, [7]documentation)
     29 
     30    GCC 8.1
     31           May 2, 2018 ([8]changes, [9]documentation)
     32 
     33 References and Acknowledgements
     34 
     35    GCC used to stand for the GNU C Compiler, but since the compiler
     36    supports several other languages aside from C, it now stands for the
     37    GNU Compiler Collection.
     38 
     39    A list of [10]successful builds is updated as new information becomes
     40    available.
     41 
     42    The GCC developers would like to thank the numerous people that have
     43    contributed new features, improvements, bug fixes, and other changes as
     44    well as test results to GCC. This [11]amazing group of volunteers is
     45    what makes GCC successful.
     46 
     47    For additional information about GCC please refer to the [12]GCC
     48    project web site or contact the [13]GCC development mailing list.
     49 
     50    To obtain GCC please use [14]our mirror sites or [15]our version
     51    control system.
     52 
     53 
     54     For questions related to the use of GCC, please consult these web
     55     pages and the [16]GCC manuals. If that fails, the
     56     [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
     57     web pages and the development of GCC are welcome on our developer
     58     list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public
     59     archives.
     60 
     61    Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and
     62    distribution of this entire article is permitted in any medium,
     63    provided this notice is preserved.
     64 
     65    These pages are [21]maintained by the GCC team. Last modified
     66    2020-03-04[22].
     67 
     68 References
     69 
     70    1. http://www.gnu.org/
     71    2. http://gcc.gnu.org/gcc-8/changes.html
     72    3. http://gcc.gnu.org/onlinedocs/8.4.0/
     73    4. http://gcc.gnu.org/gcc-8/changes.html
     74    5. http://gcc.gnu.org/onlinedocs/8.3.0/
     75    6. http://gcc.gnu.org/gcc-8/changes.html
     76    7. http://gcc.gnu.org/onlinedocs/8.2.0/
     77    8. http://gcc.gnu.org/gcc-8/changes.html
     78    9. http://gcc.gnu.org/onlinedocs/8.1.0/
     79   10. http://gcc.gnu.org/gcc-8/buildstat.html
     80   11. http://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Contributors.html
     81   12. http://gcc.gnu.org/index.html
     82   13. mailto:gcc (a] gcc.gnu.org
     83   14. http://gcc.gnu.org/mirrors.html
     84   15. http://gcc.gnu.org/git.html
     85   16. https://gcc.gnu.org/onlinedocs/
     86   17. mailto:gcc-help (a] gcc.gnu.org
     87   18. mailto:gcc (a] gcc.gnu.org
     88   19. https://gcc.gnu.org/lists.html
     89   20. https://www.fsf.org/
     90   21. https://gcc.gnu.org/about.html
     91   22. http://validator.w3.org/check/referer
     92 ======================================================================
     93 http://gcc.gnu.org/gcc-8/changes.html
     94                               GCC 8 Release Series
     95                         Changes, New Features, and Fixes
     96 
     97    This page is a "brief" summary of some of the huge number of
     98    improvements in GCC 8. You may also want to check out our [1]Porting to
     99    GCC 8 page and the [2]full GCC documentation.
    100 
    101 Caveats
    102 
    103      * Support for the obsolete SDB/coff debug info format has been
    104        removed. The option -gcoff no longer does anything.
    105      * The Cilk+ extensions to the C and C++ languages have been removed.
    106      * The MPX extensions to the C and C++ languages have been deprecated
    107        and will be removed in a future release.
    108      * The extension allowing arithmetic on std::atomic<void*> and types
    109        like std::atomic<R(*)()> has been deprecated.
    110      * The non-standard C++0x std::copy_exception function was removed.
    111        std::make_exception_ptr should be used instead.
    112      * Support for the powerpc*-*-*spe* target ports which have been
    113        recently unmaintained and untested in GCC has been declared
    114        obsolete in GCC 8 as [3]announced. Unless there is activity to
    115        revive them, the next release of GCC will have their sources
    116        permanently removed.
    117 
    118 General Improvements
    119 
    120      * Inter-procedural optimization improvements:
    121           + Reworked run-time estimation metrics leading to more realistic
    122             guesses driving inliner and cloning heuristics.
    123           + The ipa-pure-const pass is extended to propagate the malloc
    124             attribute, and the corresponding warning option
    125             -Wsuggest-attribute=malloc emits a diagnostic for functions
    126             which can be annotated with the malloc attribute.
    127      * Profile driven optimization improvements:
    128           + New infrastructure for representing profiles (both statically
    129             guessed and profile feedback) which allows propagation of
    130             additional information about the reliability of the profile.
    131           + A number of improvements in the profile updating code solving
    132             problems found by new verification code.
    133           + Static detection of code which is not executed in a valid run
    134             of the program. This includes paths which trigger undefined
    135             behavior as well as calls to functions declared with the cold
    136             attribute. Newly the noreturn attribute does not imply all
    137             effects of cold to differentiate between exit (which is
    138             noreturn) and abort (which is in addition not executed in
    139             valid runs).
    140           + -freorder-blocks-and-partition, a pass splitting function
    141             bodies into hot and cold regions, is now enabled by default at
    142             -O2 and higher for x86 and x86-64.
    143      * Link-time optimization improvements:
    144           + We have significantly improved debug information on ELF
    145             targets using DWARF by properly preserving language-specific
    146             information. This allows for example the libstdc++
    147             pretty-printers to work with LTO optimized executables.
    148      * A new option -fcf-protection=[full|branch|return|none] is
    149        introduced to perform code instrumentation to increase program
    150        security by checking that target addresses of control-flow transfer
    151        instructions (such as indirect function call, function return,
    152        indirect jump) are valid. Currently the instrumentation is
    153        supported on x86 GNU/Linux targets only. See the user guide for
    154        further information about the option syntax and section "New
    155        Targets and Target Specific Improvements" for IA-32/x86-64 for more
    156        details.
    157      * The -gcolumn-info option is now enabled by default. It includes
    158        column information in addition to just filenames and line numbers
    159        in DWARF debugging information.
    160      * The polyhedral-based loop nest optimization pass
    161        -floop-nest-optimize has been overhauled. It's still considered
    162        experimental and may not result in any runtime improvements.
    163      * Two new classical loop nest optimization passes have been added.
    164        -floop-unroll-and-jam performs outer loop unrolling and fusing of
    165        the inner loop copies. -floop-interchange exchanges loops in a loop
    166        nest to improve data locality. Both passes are enabled by default
    167        at -O3 and above.
    168      * The classic loop nest optimization pass -ftree-loop-distribution
    169        has been improved and enabled by default at -O3 and above. It
    170        supports loop nest distribution in some restricted scenarios; it
    171        also supports cancellable innermost loop distribution with loop
    172        versioning under run-time alias checks.
    173      * The new option -fstack-clash-protection causes the compiler to
    174        insert probes whenever stack space is allocated statically or
    175        dynamically to reliably detect stack overflows and thus mitigate
    176        the attack vector that relies on jumping over a stack guard page as
    177        provided by the operating system.
    178      * A new pragma GCC unroll has been implemented in the C family of
    179        languages, as well as Fortran and Ada, so as to make it possible
    180        for the user to have a finer-grained control over the loop
    181        unrolling optimization.
    182      * GCC has been enhanced to detect more instances of meaningless or
    183        mutually exclusive attribute specifications and handle such
    184        conflicts more consistently. Mutually exclusive attribute
    185        specifications are ignored with a warning regardless of whether
    186        they appear on the same declaration or on distinct declarations of
    187        the same entity. For example, because the noreturn attribute on the
    188        second declaration below is mutually exclusive with the malloc
    189        attribute on the first, it is ignored and a warning is issued.
    190 >
    191       void* __attribute__ ((malloc)) f (unsigned);
    192       void* __attribute__ ((noreturn)) f (unsigned);
    193 
    194       warning: ignoring attribute 'noreturn' because it conflicts with attribute
    195  'malloc' [-Wattributes]
    196      * The gcov tool can distinguish functions that begin on a same line
    197        in a source file. This can be a different template instantiation or
    198        a class constructor:
    199 
    200 File 'ins.C'
    201 Lines executed:100.00% of 8
    202 Creating 'ins.C.gcov'
    203 
    204         -:    0:Source:ins.C
    205         -:    0:Graph:ins.gcno
    206         -:    0:Data:ins.gcda
    207         -:    0:Runs:1
    208         -:    0:Programs:1
    209         -:    1:template<class T>
    210         -:    2:class Foo
    211         -:    3:{
    212         -:    4: public:
    213         2:    5:   Foo(): b (1000) {}
    214 ------------------
    215 Foo<char>::Foo():
    216         1:    5:   Foo(): b (1000) {}
    217 ------------------
    218 Foo<int>::Foo():
    219         1:    5:   Foo(): b (1000) {}
    220 ------------------
    221         2:    6:   void inc () { b++; }
    222 ------------------
    223 Foo<char>::inc():
    224         1:    6:   void inc () { b++; }
    225 ------------------
    226 Foo<int>::inc():
    227         1:    6:   void inc () { b++; }
    228 ------------------
    229         -:    7:
    230         -:    8:  private:
    231         -:    9:   int b;
    232         -:   10:};
    233         -:   11:
    234         1:   12:int main(int argc, char **argv)
    235         -:   13:{
    236         1:   14:  Foo<int> a;
    237         1:   15:  Foo<char> b;
    238         -:   16:
    239         1:   17:  a.inc ();
    240         1:   18:  b.inc ();
    241         1:   19:}
    242 
    243      * The gcov tool has more accurate numbers for execution of lines in a
    244        source file.
    245      * The gcov tool can use TERM colors to provide more readable output.
    246      * AddressSanitizer gained a new pair of sanitization options,
    247        -fsanitize=pointer-compare and -fsanitize=pointer-subtract, which
    248        warn about subtraction (or comparison) of pointers that point to a
    249        different memory object:
    250 
    251 int
    252 main ()
    253 {
    254   /* Heap allocated memory.  */
    255   char *heap1 = (char *)__builtin_malloc (42);
    256   char *heap2 = (char *)__builtin_malloc (42);
    257   if (heap1 > heap2)
    258       return 1;
    259 
    260   return 0;
    261 }
    262 
    263 ==17465==ERROR: AddressSanitizer: invalid-pointer-pair: 0x604000000010 0x6040000
    264 00050
    265     #0 0x40070f in main /tmp/pointer-compare.c:7
    266     #1 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86)
    267     #2 0x400629 in _start (/tmp/a.out+0x400629)
    268 
    269 0x604000000010 is located 0 bytes inside of 42-byte region [0x604000000010,0x604
    270 00000003a)
    271 allocated by thread T0 here:
    272     #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan
    273 _malloc_linux.cc:86
    274     #1 0x4006ea in main /tmp/pointer-compare.c:5
    275     #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86)
    276 
    277 0x604000000050 is located 0 bytes inside of 42-byte region [0x604000000050,0x604
    278 00000007a)
    279 allocated by thread T0 here:
    280     #0 0x7ffff6efb390 in __interceptor_malloc ../../../../libsanitizer/asan/asan
    281 _malloc_linux.cc:86
    282     #1 0x4006f8 in main /tmp/pointer-compare.c:6
    283     #2 0x7ffff6a72a86 in __libc_start_main (/lib64/libc.so.6+0x21a86)
    284 
    285 SUMMARY: AddressSanitizer: invalid-pointer-pair /tmp/pointer-compare.c:7 in main
    286 
    287      * The store merging pass has been enhanced to handle bit-fields and
    288        not just constant stores, but also data copying from adjacent
    289        memory locations into other adjacent memory locations, including
    290        bitwise logical operations on the data. The pass can also handle
    291        byte swapping into memory locations.
    292      * The undefined behavior sanitizer gained two new options included in
    293        -fsanitize=undefined: -fsanitize=builtin which diagnoses at run
    294        time invalid arguments to __builtin_clz or __builtin_ctz prefixed
    295        builtins, and -fsanitize=pointer-overflow which performs cheap run
    296        time tests for pointer wrapping.
    297      * A new attribute no_sanitize can be applied to functions to instruct
    298        the compiler not to do sanitization of the options provided as
    299        arguments to the attribute. Acceptable values for no_sanitize match
    300        those acceptable by the -fsanitize command-line option.
    301 
    302 void __attribute__ ((no_sanitize ("alignment", "object-size")))
    303 f () { /* Do something. */; }
    304 
    305 New Languages and Language specific improvements
    306 
    307   Ada
    308 
    309      * For its internal exception handling used on the host for error
    310        recovery in the front-end, the compiler now relies on the native
    311        exception handling mechanism of the host platform, which should be
    312        more efficient than the former mechanism.
    313 
    314   BRIG (HSAIL)
    315 
    316    In this release cycle, the focus for the BRIGFE was on stabilization
    317    and performance improvements. Also a couple of completely new features
    318    were added.
    319      * Improved support for function and module scope group segment
    320        variables. PRM specs define function and module scope group segment
    321        variables as an experimental feature. However, PRM test suite uses
    322        them. Now group segment is handled by separate book keeping of
    323        module scope and function (kernel) offsets. Each function has a
    324        "frame" in the group segment offset to which is given as an
    325        argument, similar to traditional call stack frame handling.
    326      * Reduce the number of type conversions due to the untyped HSAIL
    327        registers. Instead of always representing the HSAIL's untyped
    328        registers as unsigned int, the gccbrig now pre-analyzes the BRIG
    329        code and builds the register variables as a type used the most when
    330        storing or reading data to/from each register. This reduces the
    331        number of total casts which cannot be always optimized away.
    332      * Support for BRIG_KIND_NONE directives.
    333      * Made -O3 the default optimization level for BRIGFE.
    334      * Fixed illegal addresses generated from address expressions which
    335        refer only to offset 0.
    336      * Fixed a bug with reg+offset addressing on 32b segments. In 'large'
    337        mode, the offset is treated as 32bits unless it's in global,
    338        read-only or kernarg address space.
    339      * Fixed a crash caused sometimes by calls with more than 4 arguments.
    340      * Fixed a mis-execution issue with kernels that have both unexpanded
    341        ID functions and calls to subfunctions.
    342      * Treat HSAIL barrier builtins as setjmp/longjump style functions to
    343        avoid illegal optimizations.
    344      * Ensure per WI copies of private variables are aligned correctly.
    345      * libhsail-rt: Assume the host runtime allocates the work group
    346        memory.
    347 
    348   C family
    349 
    350      * New command-line options have been added for the C and C++
    351        compilers:
    352           + [4]-Wmultistatement-macros warns about unsafe macros expanding
    353             to multiple statements used as a body of a statement such as
    354             if, else, while, switch, or for.
    355           + [5]-Wstringop-truncation warns for calls to bounded string
    356             manipulation functions such as strncat, strncpy, and stpncpy
    357             that might either truncate the copied string or leave the
    358             destination unchanged. For example, the following call to
    359             strncat is diagnosed because it appends just three of the four
    360             characters from the source string.
    361 void append (char *buf, size_t bufsize)
    362 {
    363     strncat (buf, ".txt", 3);
    364 }
    365 warning: 'strncat' output truncated copying 3 bytes from a string of length 4 [-
    366 Wstringop-truncation]
    367             Similarly, in the following example, the call to strncpy
    368             specifies the size of the destination buffer as the bound. If
    369             the length of the source string is equal to or greater than
    370             this size the result of the copy will not be NUL-terminated.
    371             Therefore, the call is also diagnosed. To avoid the warning,
    372             specify sizeof buf - 1 as the bound and set the last element
    373             of the buffer to NUL.
    374 void copy (const char *s)
    375 {
    376     char buf[80];
    377     strncpy (buf, s, sizeof buf);
    378     
    379 }
    380 warning: 'strncpy' specified bound 80 equals destination size [-Wstringop-trunca
    381 tion]
    382             The -Wstringop-truncation option is included in -Wall.
    383             Note that due to GCC bug [6]82944, defining strncat, strncpy,
    384             or stpncpy as a macro in a system header as some
    385             implementations do, suppresses the warning.
    386           + [7]-Wif-not-aligned controls warnings issued in response to
    387             invalid uses of objects declared with attribute
    388             [8]warn_if_not_aligned.
    389             The -Wif-not-aligned option is included in -Wall.
    390           + [9]-Wmissing-attributes warns when a declaration of a function
    391             is missing one or more attributes that a related function is
    392             declared with and whose absence may adversely affect the
    393             correctness or efficiency of generated code. For example, in
    394             C++, the warning is issued when an explicit specialization of
    395             a primary template declared with attribute alloc_align,
    396             alloc_size, assume_aligned, format, format_arg, malloc, or
    397             nonnull is declared without it. Attributes deprecated, error,
    398             and warning suppress the warning.
    399             The -Wmissing-attributes option is included in -Wall.
    400           + [10]-Wpacked-not-aligned warns when a struct or union declared
    401             with attribute packed defines a member with an explicitly
    402             specified alignment greater than 1. Such a member will wind up
    403             under-aligned. For example, a warning will be issued for the
    404             definition of struct A in the following:
    405 struct __attribute__ ((aligned (8)))
    406 S8 { char a[8]; };
    407 
    408 struct __attribute__ ((packed)) A
    409 {
    410     struct S8 s8;
    411 };
    412 warning: alignment 1 of 'struct S' is less than 8 [-Wpacked-not-aligned]
    413             The -Wpacked-not-aligned option is included in -Wall.
    414           + -Wcast-function-type warns when a function pointer is cast to
    415             an incompatible function pointer. This warning is enabled by
    416             -Wextra.
    417           + -Wsizeof-pointer-div warns for suspicious divisions of the
    418             size of a pointer by the size of the elements it points to,
    419             which looks like the usual way to compute the array size but
    420             won't work out correctly with pointers. This warning is
    421             enabled by -Wall.
    422           + -Wcast-align=strict warns whenever a pointer is cast such that
    423             the required alignment of the target is increased. For
    424             example, warn if a char * is cast to an int * regardless of
    425             the target machine.
    426           + -fprofile-abs-path creates absolute path names in the .gcno
    427             files. This allows gcov to find the correct sources in
    428             projects where compilations occur with different working
    429             directories.
    430      * -fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer and
    431        signed integer overflow is now undefined by default at all
    432        optimization levels. Using -fsanitize=signed-integer-overflow is
    433        now the preferred way to audit code, -Wstrict-overflow is
    434        deprecated.
    435      * The [11]-Warray-bounds option has been improved to detect more
    436        instances of out-of-bounds array indices and pointer offsets. For
    437        example, negative or excessive indices into flexible array members
    438        and string literals are detected.
    439      * The [12]-Wrestrict option introduced in GCC 7 has been enhanced to
    440        detect many more instances of overlapping accesses to objects via
    441        restrict-qualified arguments to standard memory and string
    442        manipulation functions such as memcpy and strcpy. For example, the
    443        strcpy call in the function below attempts to truncate the string
    444        by replacing its initial characters with the last four. However,
    445        because the function writes the terminating NUL into a[4], the
    446        copies overlap and the call is diagnosed.
    447 void f (void)
    448 {
    449     char a[] = "abcd1234";
    450     strcpy (a, a + 4);
    451     
    452 }
    453 warning: 'strcpy' accessing 5 bytes at offsets 0 and 4 overlaps 1 byte at offset
    454  4 [-Wrestrict]
    455        The -Wrestrict option is included in -Wall.
    456      * Several optimizer enhancements have enabled improvements to the
    457        [13]-Wformat-overflow and [14]-Wformat-truncation options. The
    458        warnings detect more instances of buffer overflow and truncation
    459        than in GCC 7 and are better at avoiding certain kinds of false
    460        positives.
    461      * When reporting mismatching argument types at a function call, the C
    462        and C++ compilers now underline both the argument and the pertinent
    463        parameter in the declaration.
    464 $ gcc arg-type-mismatch.cc
    465 arg-type-mismatch.cc: In function 'int caller(int, int, float)':
    466 arg-type-mismatch.cc:5:24: error: invalid conversion from 'int' to 'const char*'
    467  [-fpermissive]
    468    return callee(first, second, third);
    469                         ^~~~~~
    470 arg-type-mismatch.cc:1:40: note:   initializing argument 2 of 'int callee(int, c
    471 onst char*, float)'
    472  extern int callee(int one, const char *two, float three);
    473                             ~~~~~~~~~~~~^~~
    474 
    475      * When reporting on unrecognized identifiers, the C and C++ compilers
    476        will now emit fix-it hints suggesting #include directives for
    477        various headers in the C and C++ standard libraries.
    478 $ gcc incomplete.c
    479 incomplete.c: In function 'test':
    480 incomplete.c:3:10: error: 'NULL' undeclared (first use in this function)
    481    return NULL;
    482           ^~~~
    483 incomplete.c:3:10: note: 'NULL' is defined in header '<stddef.h>'; did you forge
    484 t to '#include <stddef.h>'?
    485 incomplete.c:1:1:
    486 +#include <stddef.h>
    487  const char *test(void)
    488 incomplete.c:3:10:
    489    return NULL;
    490           ^~~~
    491 incomplete.c:3:10: note: each undeclared identifier is reported only once for ea
    492 ch function it appears in
    493 
    494 $ gcc incomplete.cc
    495 incomplete.cc:1:6: error: 'string' in namespace 'std' does not name a type
    496  std::string s("hello world");
    497       ^~~~~~
    498 incomplete.cc:1:1: note: 'std::string' is defined in header '<string>'; did you
    499 forget to '#include <string>'?
    500 +#include <string>
    501  std::string s("hello world");
    502  ^~~
    503 
    504      * The C and C++ compilers now use more intuitive locations when
    505        reporting on missing semicolons, and offer fix-it hints:
    506 $ gcc t.c
    507 t.c: In function 'test':
    508 t.c:3:12: error: expected ';' before '}' token
    509    return 42
    510             ^
    511             ;
    512  }
    513  ~
    514 
    515      * When reporting on missing '}' and ')' tokens, the C and C++
    516        compilers will now highlight the corresponding '{' and '(' token,
    517        issuing a 'note' if it's on a separate line:
    518 $ gcc unclosed.c
    519 unclosed.c: In function 'log_when_out_of_range':
    520 unclosed.c:12:50: error: expected ')' before '{' token
    521        && (temperature < MIN || temperature > MAX) {
    522                                                   ^~
    523                                                   )
    524 unclosed.c:11:6: note: to match this '('
    525    if (logging_enabled && check_range ()
    526       ^
    527 
    528        or highlighting it directly if it's on the same line:
    529 $ gcc unclosed-2.c
    530 unclosed-2.c: In function 'test':
    531 unclosed-2.c:8:45: error: expected ')' before '{' token
    532    if (temperature < MIN || temperature > MAX {
    533       ~                                      ^~
    534                                              )
    535 
    536        They will also emit fix-it hints.
    537 
    538   C++
    539 
    540      * GCC 8 (-fabi-version=12) has a couple of corrections to the calling
    541        convention, which changes the ABI for some uncommon code:
    542           + Passing an empty class as an argument now takes up no space on
    543             x86_64, as required by the psABI.
    544           + Passing or returning a class with only deleted copy and move
    545             constructors now uses the same calling convention as a class
    546             with a non-trivial copy or move constructor. This only affects
    547             C++17 mode, as in earlier standards passing or returning such
    548             a class was impossible.
    549           + WARNING: In GCC 8.1 the second change mistakenly also affects
    550             classes with a deleted copy constructor and defaulted trivial
    551             move constructor (bug [15]c++/86094). This issue is fixed in
    552             GCC 8.2 (-fabi-version=13).
    553        You can test whether these changes affect your code with -Wabi=11
    554        (or -Wabi=12 in GCC 8.2 for the third issue); if these changes are
    555        problematic for your project, the GCC 7 ABI can be selected with
    556        -fabi-version=11.
    557      * The value of the C++11 alignof operator has been corrected to match
    558        C _Alignof (minimum alignment) rather than GNU __alignof__
    559        (preferred alignment); on ia32 targets this means that
    560        alignof(double) is now 4 rather than 8. Code that wants the
    561        preferred alignment should use __alignof__ instead.
    562      * New command-line options have been added for the C++ compiler to
    563        control warnings:
    564           + [16]-Wclass-memaccess warns when objects of non-trivial class
    565             types are manipulated in potentially unsafe ways by raw memory
    566             functions such as memcpy, or realloc. The warning helps detect
    567             calls that bypass user-defined constructors or copy-assignment
    568             operators, corrupt virtual table pointers, data members of
    569             const-qualified types or references, or member pointers. The
    570             warning also detects calls that would bypass access controls
    571             to data members. For example, a call such as:
    572         memcpy (&std::cout, &std::cerr, sizeof std::cout);
    573             results in
    574         warning: 'void* memcpy(void*, const void*, long unsigned int)' writing t
    575 o an object of type 'std::ostream' {aka 'class std::basic_ostream<char>'} with n
    576 o trivial copy-assignment [-Wclass-memaccess]
    577             The -Wclass-memaccess option is included in -Wall.
    578      * The C++ front end has experimental support for some of the upcoming
    579        C++2a draft features with the -std=c++2a or -std=gnu++2a flags,
    580        including designated initializers, default member initializers for
    581        bit-fields, __VA_OPT__ (except that #__VA_OPT__ is unsupported),
    582        lambda [=, this] captures, etc. For a full list of new features,
    583        see [17]the C++ status page.
    584      * When reporting on attempts to access private fields of a class or
    585        struct, the C++ compiler will now offer fix-it hints showing how to
    586        use an accessor function to get at the field in question, if one
    587        exists.
    588 $ gcc accessor.cc
    589 accessor.cc: In function 'void test(foo*)':
    590 accessor.cc:12:12: error: 'double foo::m_ratio' is private within this context
    591    if (ptr->m_ratio >= 0.5)
    592             ^~~~~~~
    593 accessor.cc:7:10: note: declared private here
    594    double m_ratio;
    595           ^~~~~~~
    596 accessor.cc:12:12: note: field 'double foo::m_ratio' can be accessed via 'double
    597  foo::get_ratio() const'
    598    if (ptr->m_ratio >= 0.5)
    599             ^~~~~~~
    600             get_ratio()
    601 
    602      * The C++ compiler can now give you a hint if you use a macro before
    603        it was defined (e.g. if you mess up the order of your #include
    604        directives):
    605 $ gcc ordering.cc
    606 ordering.cc:2:24: error: expected ';' at end of member declaration
    607    virtual void clone() const OVERRIDE { }
    608                         ^~~~~
    609                              ;
    610 ordering.cc:2:30: error: 'OVERRIDE' does not name a type
    611    virtual void clone() const OVERRIDE { }
    612                               ^~~~~~~~
    613 ordering.cc:2:30: note: the macro 'OVERRIDE' had not yet been defined
    614 In file included from ordering.cc:5:
    615 c++11-compat.h:2: note: it was later defined here
    616  #define OVERRIDE override
    617 
    618 
    619      * The -Wold-style-cast diagnostic can now emit fix-it hints telling
    620        you when you can use a static_cast, const_cast, or
    621        reinterpret_cast.
    622 $ gcc -c old-style-cast-fixits.cc -Wold-style-cast
    623 old-style-cast-fixits.cc: In function 'void test(void*)':
    624 old-style-cast-fixits.cc:5:19: warning: use of old-style cast to 'struct foo*' [
    625 -Wold-style-cast]
    626    foo *f = (foo *)ptr;
    627                    ^~~
    628             ----------
    629             static_cast<foo *> (ptr)
    630 
    631      * When reporting on problems within extern "C" linkage
    632        specifications, the C++ compiler will now display the location of
    633        the start of the extern "C".
    634 $ gcc -c extern-c.cc
    635 extern-c.cc:3:1: error: template with C linkage
    636  template <typename T> void test (void);
    637  ^~~~~~~~
    638 In file included from extern-c.cc:1:
    639 unclosed.h:1:1: note: 'extern "C"' linkage started here
    640  extern "C" {
    641  ^~~~~~~~~~
    642 extern-c.cc:3:39: error: expected '}' at end of input
    643  template <typename T> void test (void);
    644                                        ^
    645 In file included from extern-c.cc:1:
    646 unclosed.h:1:12: note: to match this '{'
    647  extern "C" {
    648             ^
    649 
    650      * When reporting on mismatching template types, the C++ compiler will
    651        now use color to highlight the mismatching parts of the template,
    652        and will elide the parameters that are common between two
    653        mismatching templates, printing [...] instead:
    654 $ gcc templates.cc
    655 templates.cc: In function 'void test()':
    656 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl
    657 e>' to 'vector<int>'
    658    fn_1(vector<double> ());
    659         ^~~~~~~~~~~~~~~~~
    660 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<[...]
    661 ,double>' to 'map<[...],int>'
    662    fn_2(map<int, double>());
    663         ^~~~~~~~~~~~~~~~~~
    664 
    665        Those [...] elided parameters can be seen using -fno-elide-type:
    666 $ gcc templates.cc -fno-elide-type
    667 templates.cc: In function 'void test()':
    668 templates.cc:9:8: error: could not convert 'vector<double>()' from 'vector<doubl
    669 e>' to 'vector<int>'
    670    fn_1(vector<double> ());
    671         ^~~~~~~~~~~~~~~~~
    672 templates.cc:10:8: error: could not convert 'map<int, double>()' from 'map<int,d
    673 ouble>' to 'map<int,int>'
    674    fn_2(map<int, double>());
    675         ^~~~~~~~~~~~~~~~~~
    676 
    677        The C++ compiler has also gained an option
    678        -fdiagnostics-show-template-tree which visualizes such mismatching
    679        templates in a hierarchical form:
    680 $ gcc templates-2.cc -fdiagnostics-show-template-tree
    681 templates-2.cc: In function 'void test()':
    682 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou
    683 ble>' to 'vector<int>'
    684   vector<
    685     [double != int]>
    686    fn_1(vector<double> ());
    687         ^~~~~~~~~~~~~~~~~
    688 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve
    689 ctor<double> >()' from 'map<map<[...],vector<double>>,vector<double>>' to 'map<m
    690 ap<[...],vector<float>>,vector<float>>'
    691   map<
    692     map<
    693       [...],
    694       vector<
    695         [double != float]>>,
    696     vector<
    697       [double != float]>>
    698    fn_2(map<map<int, vector<double>>, vector<double>> ());
    699         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    700 
    701        which again works with -fno-elide-type:
    702 $ gcc templates-2.cc -fdiagnostics-show-template-tree -fno-elide-type
    703 templates-2.cc: In function 'void test()':
    704 templates-2.cc:9:8: error: could not convert 'vector<double>()' from 'vector<dou
    705 ble>' to 'vector<int>'
    706   vector<
    707     [double != int]>
    708    fn_1(vector<double> ());
    709         ^~~~~~~~~~~~~~~~~
    710 templates-2.cc:10:8: error: could not convert 'map<map<int, vector<double> >, ve
    711 ctor<double> >()' from 'map<map<int,vector<double>>,vector<double>>' to 'map<map
    712 <int,vector<float>>,vector<float>>'
    713   map<
    714     map<
    715       int,
    716       vector<
    717         [double != float]>>,
    718     vector<
    719       [double != float]>>
    720    fn_2(map<map<int, vector<double>>, vector<double>> ());
    721         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    722 
    723      * Flowing off the end of a non-void function is considered
    724        unreachable and may be subject to optimization on that basis. As a
    725        result of this change, -Wreturn-type warnings are enabled by
    726        default for C++.
    727 
    728     Runtime Library (libstdc++)
    729 
    730      * Improved experimental support for C++17, including the following
    731        features:
    732           + Deduction guides to support class template argument deduction.
    733           + std::filesystem implementation.
    734           + std::char_traits<char> and std::char_traits<wchar_t> are
    735             usable in constant expressions.
    736           + std::to_chars and std::from_chars (for integers only, not for
    737             floating point types).
    738      * Experimental support for C++2a: std::to_address (thanks to Glen
    739        Fernandes) and std::endian.
    740      * On GNU/Linux, std::random_device::entropy() accesses the kernel's
    741        entropy count for the random device, if known (thanks to Xi
    742        Ruoyao).
    743      * Support for std::experimental::source_location.
    744      * AddressSanitizer integration for std::vector, detecting
    745        out-of-range accesses to the unused capacity of a vector.
    746      * Extensions __gnu_cxx::airy_ai and __gnu_cxx::airy_bi added to the
    747        Mathematical Special Functions.
    748 
    749   Fortran
    750 
    751      * The main version of libfortran has been changed to 5.
    752      * Parameterized derived types, a major feature of Fortran 2003, have
    753        been implemented.
    754      * Partial support is provided for Fortran 2018 teams, which are
    755        hierarchical subsets of images that execute independently of other
    756        image subsets.
    757      * The maximum rank for arrays has been increased to 15, conforming to
    758        the Fortran 2008 standard.
    759      * Transformational intrinsics are now fully supported in
    760        initialization expressions.
    761      * New flag -fc-prototypes to write C prototypes for BIND(C)
    762        procedures and variables.
    763      * If -fmax-stack-var-size is honored if given together with -Ofast,
    764        -fstack-arrays is no longer set in that case.
    765      * New options -fdefault-real-16 and -fdefault-real-10 to control the
    766        default kind of REAL variables.
    767      * A warning is now issued if an array subscript inside a DO loop
    768        could lead to an out-of-bounds-access. The new option
    769        -Wdo-subscript, enabled by -Wextra, warns about this even if the
    770        compiler can not prove that the code will be executed.
    771      * The Fortran front end now attempts to interchange loops if it is
    772        deemed profitable. So far, this is restricted to FORALL and DO
    773        CONCURRENT statements with multiple indices. This behavior be
    774        controlled with the new flag -ffrontend-loop-interchange, which is
    775        enabled with optimization by default. The
    776        -Wfrontend-loop-interchange option warns about such occurrences.
    777      * When an actual argument contains too few elements for a dummy
    778        argument, an error is now issued. The -std=legacy option can be
    779        used to still compile such code.
    780      * The RECL= argument to OPEN and INQUIRE statements now allows 64-bit
    781        integers, making records larger than 2GiB possible.
    782      * The GFORTRAN_DEFAULT_RECL environment variable no longer has any
    783        effect. The record length for preconnected units is now larger than
    784        any practical limit, same as for sequential access units opened
    785        without an explicit RECL= specifier.
    786      * Character variables longer than HUGE(0) elements are now possible
    787        on 64-bit targets. Note that this changes the procedure call ABI
    788        for all procedures with character arguments on 64-bit targets, as
    789        the type of the hidden character length argument has changed. The
    790        hidden character length argument is now of type INTEGER(C_SIZE_T).
    791      * Partial support is provided for Fortran 2018 teams, which are
    792        hierarchical subsets of images that execute independently of other
    793        image subsets.
    794 
    795   Go
    796 
    797      * GCC 8 provides a complete implementation of the Go 1.10.1 user
    798        packages.
    799      * The garbage collector is now fully concurrent. As before, values
    800        stored on the stack are scanned conservatively, but value stored in
    801        the heap are scanned precisely.
    802      * Escape analysis is fully implemented and enabled by default in the
    803        Go frontend. This significantly reduces the number of heap
    804        allocations by allocating values on the stack instead.
    805 
    806 libgccjit
    807 
    808    The libgccjit API gained four new entry points:
    809      * [18]gcc_jit_type_get_vector and
    810      * [19]gcc_jit_context_new_rvalue_from_vector for working with
    811        vectors,
    812      * [20]gcc_jit_type_get_aligned
    813      * [21]gcc_jit_function_get_address
    814 
    815    The C code generated by [22]gcc_jit_context_dump_reproducer_to_file is
    816    now easier-to-read.
    817 
    818 New Targets and Target Specific Improvements
    819 
    820   AArch64
    821 
    822      * The Armv8.4-A architecture is now supported. It can be used by
    823        specifying the -march=armv8.4-a option.
    824      * The Dot Product instructions are now supported as an optional
    825        extension to the Armv8.2-A architecture and newer and are mandatory
    826        on Armv8.4-A. The extension can be used by specifying the +dotprod
    827        architecture extension. E.g. -march=armv8.2-a+dotprod.
    828      * The Armv8-A +crypto extension has now been split into two
    829        extensions for finer grained control:
    830           + +aes which contains the Armv8-A AES crytographic instructions.
    831           + +sha2 which contains the Armv8-A SHA2 and SHA1 cryptographic
    832             instructions.
    833        Using +crypto will now enable these two extensions.
    834      * New Armv8.4-A FP16 Floating Point Multiplication Variant
    835        instructions have been added. These instructions are mandatory in
    836        Armv8.4-A but available as an optional extension to Armv8.2-A and
    837        Armv8.3-A. The new extension can be used by specifying the +fp16fml
    838        architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A
    839        the instructions can be enabled by specifying +fp16.
    840      * New cryptographic instructions have been added as optional
    841        extensions to Armv8.2-A and newer. These instructions can be
    842        enabled with:
    843           + +sha3 New SHA3 and SHA2 instructions from Armv8.4-A. This
    844             implies +sha2.
    845           + +sm4 New SM3 and SM4 instructions from Armv8.4-A.
    846      * The Scalable Vector Extension (SVE) is now supported as an optional
    847        extension to the Armv8.2-A architecture and newer. This support
    848        includes automatic vectorization with SVE instructions, but it does
    849        not yet include the SVE Arm C Language Extensions (ACLE). It can be
    850        enabled by specifying the +sve architecture extension (for example,
    851        -march=armv8.2-a+sve). By default, the generated code works with
    852        all vector lengths, but it can be made specific to N-bit vectors
    853        using -msve-vector-bits=N.
    854      * Support has been added for the following processors (GCC
    855        identifiers in parentheses):
    856           + Arm Cortex-A75 (cortex-a75).
    857           + Arm Cortex-A55 (cortex-a55).
    858           + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE
    859             (cortex-a75.cortex-a55).
    860        The GCC identifiers can be used as arguments to the -mcpu or -mtune
    861        options, for example: -mcpu=cortex-a75 or -mtune=cortex-a75 or as
    862        arguments to the equivalent target attributes and pragmas.
    863 
    864   ARC
    865 
    866      * Added support for:
    867           + Fast interrupts.
    868           + Naked functions.
    869           + aux variable attributes.
    870           + uncached type qualifier.
    871           + Secure functions via sjli instruction.
    872      * New exception handling implementation.
    873      * Revamped trampoline implementation.
    874      * Refactored small data feature implementation, controlled via -G
    875        command line option.
    876      * New support for reduced register set ARC architecture
    877        configurations, controlled via -mrf16 command line option.
    878      * Refurbished and improved support for zero overhead loops.
    879        Introduced -mlpc-width command line option to control the width of
    880        lp_count register.
    881 
    882   ARM
    883 
    884      * The -mfpu option now takes a new option setting of -mfpu=auto. When
    885        set to this the floating-point and SIMD settings are derived from
    886        the settings of the -mcpu or -march options. The internal CPU
    887        configurations have been updated with information about the
    888        permitted floating-point configurations supported. See the user
    889        guide for further information about the extended option syntax for
    890        controlling architectural extensions via the -march option.
    891        -mfpu=auto is now the default setting unless the compiler has been
    892        configured with an explicit --with-fpu option.
    893      * The -march and -mcpu options now accept optional extensions to the
    894        architecture or CPU option, allowing the user to enable or disable
    895        any such extensions supported by that architecture or CPU such as
    896        (but not limited to) floating-point and AdvancedSIMD. For example:
    897        the option -mcpu=cortex-a53+nofp will generate code for the
    898        Cortex-A53 processor with no floating-point support. This, in
    899        combination with the new -mfpu=auto option, provides a
    900        straightforward way of specifying a valid build target through a
    901        single -mcpu or -march option. The -mtune option accepts the same
    902        arguments as -mcpu but only the CPU name has an effect on tuning.
    903        The architecture extensions do not have any effect. For details of
    904        what extensions a particular architecture or CPU option supports
    905        please refer to the [23]documentation.
    906      * The -mstructure-size-boundary option has been deprecated and will
    907        be removed in a future release.
    908      * The default link behavior for Armv6 and Armv7-R targets has been
    909        changed to produce BE8 format when generating big-endian images. A
    910        new flag -mbe32 can be used to force the linker to produce legacy
    911        BE32 format images. There is no change of behavior for Armv6-M and
    912        other Armv7 or later targets: these already defaulted to BE8
    913        format. This change brings GCC into alignment with other compilers
    914        for the ARM architecture.
    915      * The Armv8-R architecture is now supported. It can be used by
    916        specifying the -march=armv8-r option.
    917      * The Armv8.3-A architecture is now supported. It can be used by
    918        specifying the -march=armv8.3-a option.
    919      * The Armv8.4-A architecture is now supported. It can be used by
    920        specifying the -march=armv8.4-a option.
    921      * The Dot Product instructions are now supported as an optional
    922        extension to the Armv8.2-A architecture and newer and are mandatory
    923        on Armv8.4-A. The extension can be used by specifying the +dotprod
    924        architecture extension. E.g. -march=armv8.2-a+dotprod.
    925      * Support for setting extensions and architectures using the GCC
    926        target pragma and attribute has been added. It can be used by
    927        specifying #pragma GCC target ("arch=..."), #pragma GCC target
    928        ("+extension"), __attribute__((target("arch=..."))) or
    929        __attribute__((target("+extension"))).
    930      * New Armv8.4-A FP16 Floating Point Multiplication Variant
    931        instructions have been added. These instructions are mandatory in
    932        Armv8.4-A but available as an optional extension to Armv8.2-A and
    933        Armv8.3-A. The new extension can be used by specifying the +fp16fml
    934        architectural extension on Armv8.2-A and Armv8.3-A. On Armv8.4-A
    935        the instructions can be enabled by specifying +fp16.
    936      * Support has been added for the following processors (GCC
    937        identifiers in parentheses):
    938           + Arm Cortex-A75 (cortex-a75).
    939           + Arm Cortex-A55 (cortex-a55).
    940           + Arm Cortex-A55/Cortex-A75 DynamIQ big.LITTLE
    941             (cortex-a75.cortex-a55).
    942           + Arm Cortex-R52 for Armv8-R (cortex-r52).
    943        The GCC identifiers can be used as arguments to the -mcpu or -mtune
    944        options, for example: -mcpu=cortex-a75 or -mtune=cortex-r52 or as
    945        arguments to the equivalent target attributes and pragmas.
    946 
    947   AVR
    948 
    949      * The AVR port now supports the following XMEGA-like devices:
    950 
    951      ATtiny212, ATtiny214, ATtiny412, ATtiny414, ATtiny416, ATtiny417,
    952      ATtiny814, ATtiny816, ATtiny817, ATtiny1614, ATtiny1616, ATtiny1617,
    953      ATtiny3214, ATtiny3216, ATtiny3217
    954        The new devices are listed under [24]-mmcu=avrxmega3.
    955           + These devices see flash memory in the RAM address space, so
    956             that features like PROGMEM and __flash are not needed any more
    957             (as opposed to other AVR families for which read-only data
    958             will be located in RAM except special, non-standard features
    959             are used to locate and access such data). This requires that
    960             the compiler is used with Binutils 2.29 or newer so that
    961             [25]read-only data will be located in flash memory.
    962           + A new command-line option -mshort-calls is supported. This
    963             option is used internally for multilib selection of the
    964             avrxmega3 variants. It is not an optimization option. Do not
    965             set it by hand.
    966      * The compiler now generates [26]efficient interrupt service routine
    967        (ISR) prologues and epilogues. This is achieved by using the new
    968        [27]AVR pseudo instruction __gcc_isr which is supported and
    969        resolved by the GNU assembler.
    970           + As the __gcc_isr pseudo-instruction will be resolved by the
    971             assembler, inline assembly is transparent to the process. This
    972             means that when inline assembly uses an instruction like INC
    973             that clobbers the condition code, then the assembler will
    974             detect this and generate an appropriate ISR prologue /
    975             epilogue chunk to save / restore SREG as needed.
    976           + A new command-line option -mno-gas-isr-prologues disables the
    977             generation of the __gcc_isr pseudo instruction. Any non-naked
    978             ISR will save and restore SREG, tmp_reg and zero_reg, no
    979             matter whether the respective register is clobbered or used.
    980           + The feature is turned on per default for all optimization
    981             levels except for -O0 and -Og. It is explicitly enabled by
    982             means of option -mgas-isr-prologues.
    983           + Support has been added for a new [28]AVR function attribute
    984             no_gccisr. It can be used to disable __gcc_isr pseudo
    985             instruction generation for individual ISRs.
    986           + This optimization is only available if GCC is configured with
    987             GNU Binutils 2.29 or newer; or at least with a version of
    988             Binutils that implements feature [29]PR21683.
    989      * The compiler no more saves / restores registers in main; the effect
    990        is the same as if attribute OS_task was specified for main. This
    991        optimization can be switched off by the new command-line option
    992        -mno-main-is-OS_task.
    993 
    994   IA-32/x86-64
    995 
    996      * The x86 port now supports the naked function attribute.
    997      * Better tuning for znver1 and Intel Core based CPUs.
    998      * Vectorization cost metrics has been reworked leading to significant
    999        improvements on some benchmarks.
   1000      * GCC now supports the Intel CPU named Cannonlake through
   1001        -march=cannonlake. The switch enables the AVX512VBMI, AVX512IFMA
   1002        and SHA ISA extensions.
   1003      * GCC now supports the Intel CPU named Icelake through
   1004        -march=icelake. The switch enables the AVX512VNNI, GFNI, VAES,
   1005        AVX512VBMI2, VPCLMULQDQ, AVX512BITALG, RDPID and AVX512VPOPCNTDQ
   1006        ISA extensions.
   1007      * GCC now supports the Intel Control-flow Enforcement Technology
   1008        (CET) extension through -fcf-protection option.
   1009 
   1010   NDS32
   1011 
   1012      * New command-line options -mext-perf, -mext-perf2, and -mext-string
   1013        have been added for performance extension instructions.
   1014 
   1015   Nios II
   1016 
   1017      * The Nios II back end has been improved to generate better-optimized
   1018        code. Changes include switching to LRA, more accurate cost models,
   1019        and more compact code for addressing static variables.
   1020      * New command-line options -mgprel-sec= and -mr0rel-sec= have been
   1021        added.
   1022      * The stack-smashing protection options are now enabled on Nios II.
   1023 
   1024   PA-RISC
   1025 
   1026      * The default call ABI on 32-bit linux has been changed from callee
   1027        copies to caller copies. This affects objects larger than eight
   1028        bytes passed by value. The goal is to improve compatibility with
   1029        x86 and resolve issues with OpenMP.
   1030      * Other PA-RISC targets are unchanged.
   1031 
   1032   PowerPC / PowerPC64 / RS6000
   1033 
   1034      * The PowerPC SPE support is split off to a separate powerpcspe port.
   1035        The separate port is deprecated and might be removed in a future
   1036        release.
   1037      * The Paired Single support (as used on some PPC750 CPUs, -mpaired,
   1038        powerpc*-*-linux*paired*) is deprecated and will be removed in a
   1039        future release.
   1040      * The Xilinx floating point support (-mxilinx-fpu,
   1041        powerpc-xilinx-eabi*) is deprecated and will be removed in a future
   1042        release.
   1043      * Support for using big-endian AltiVec intrinsics on a little-endian
   1044        target (-maltivec=be) is deprecated and will be removed in a future
   1045        release.
   1046 
   1047   Tile
   1048 
   1049      * The TILE-Gx port is deprecated and will be removed in a future
   1050        release.
   1051 
   1052 Operating Systems
   1053 
   1054   Windows
   1055 
   1056      * GCC on Microsoft Windows can now be configured via
   1057        --enable-mingw-wildcard or --disable-mingw-wildcard to force a
   1058        specific behavior for GCC itself with regards to supporting the
   1059        wildcard character. Prior versions of GCC would follow the
   1060        configuration of the MinGW runtime. This behavior can still be
   1061        obtained by not using the above options or by using
   1062        --enable-mingw-wildcard=platform.
   1063 
   1064 Improvements for plugin authors
   1065 
   1066      * Plugins can now register a callback hook for when comments are
   1067        encountered by the C and C++ compilers, e.g. allowing for plugins
   1068        to handle documentation markup in code comments.
   1069      * The gdbinit support script for debugging GCC now has a
   1070        break-on-diagnostic command, providing an easy way to trigger a
   1071        breakpoint whenever a diagnostic is emitted.
   1072      * The API for creating fix-it hints now supports newlines, and for
   1073        emitting mutually incompatible fix-it hints for one diagnostic.
   1074 
   1075 GCC 8.1
   1076 
   1077    This is the [30]list of problem reports (PRs) from GCC's bug tracking
   1078    system that are known to be fixed in the 8.1 release. This list might
   1079    not be complete (that is, it is possible that some PRs that have been
   1080    fixed are not listed here).
   1081 
   1082 GCC 8.2
   1083 
   1084    This is the [31]list of problem reports (PRs) from GCC's bug tracking
   1085    system that are known to be fixed in the 8.2 release. This list might
   1086    not be complete (that is, it is possible that some PRs that have been
   1087    fixed are not listed here).
   1088 
   1089   General Improvements
   1090 
   1091      * Fixed LTO link-time performance problems caused by an overflow in
   1092        the partitioning algorithm while building large binaries.
   1093 
   1094   Language Specific Changes
   1095 
   1096     C++
   1097 
   1098    GCC 8.2 fixed a bug introduced in GCC 8.1 affecting passing or
   1099    returning of classes with a deleted copy constructor and defaulted
   1100    trivial move constructor (bug [32]c++/86094). GCC 8.2 introduces
   1101    -fabi-version=13 and makes it the default, ABI incompatibilities
   1102    between GCC 8.1 and 8.2 can be reported with -Wabi=12. See [33]C++
   1103    changes for more details.
   1104 
   1105   Target Specific Changes
   1106 
   1107     IA-32/x86-64
   1108 
   1109      * -mtune=native performance regression [34]PR84413 on Intel Skylake
   1110        processors has been fixed.
   1111 
   1112 GCC 8.3
   1113 
   1114    This is the [35]list of problem reports (PRs) from GCC's bug tracking
   1115    system that are known to be fixed in the 8.3 release. This list might
   1116    not be complete (that is, it is possible that some PRs that have been
   1117    fixed are not listed here).
   1118 
   1119   Windows
   1120 
   1121      * A C++ Microsoft ABI bitfield layout bug, [36]PR87137 has been
   1122        fixed. A non-field declaration could cause the current bitfield
   1123        allocation unit to be completed, incorrectly placing a following
   1124        bitfield into a new allocation unit. The Microsoft ABI is selected
   1125        for:
   1126           + Mingw targets
   1127           + PowerPC, IA-32 or x86-64 targets when the -mms-bitfields
   1128             option is specified, or __attribute__((ms_struct)) is used
   1129           + SuperH targets when the -mhitachi option is specified, or
   1130             __attribute__((renesas)) is used
   1131        GCC 8 introduced additional cases of this defect, but rather than
   1132        resolve only those regressions, we decided to resolve all the cases
   1133        of this defect in single change.
   1134 
   1135 GCC 8.4
   1136 
   1137    This is the [37]list of problem reports (PRs) from GCC's bug tracking
   1138    system that are known to be fixed in the 8.4 release. This list might
   1139    not be complete (that is, it is possible that some PRs that have been
   1140    fixed are not listed here).
   1141 
   1142 
   1143     For questions related to the use of GCC, please consult these web
   1144     pages and the [38]GCC manuals. If that fails, the
   1145     [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   1146     web pages and the development of GCC are welcome on our developer
   1147     list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public
   1148     archives.
   1149 
   1150    Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and
   1151    distribution of this entire article is permitted in any medium,
   1152    provided this notice is preserved.
   1153 
   1154    These pages are [43]maintained by the GCC team. Last modified
   1155    2020-03-04[44].
   1156 
   1157 References
   1158 
   1159    1. http://gcc.gnu.org/gcc-8/porting_to.html
   1160    2. http://gcc.gnu.org/onlinedocs/index.html#current
   1161    3. https://gcc.gnu.org/ml/gcc/2018-04/msg00102.html
   1162    4. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmultistatement-macros
   1163    5. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wstringop-truncation
   1164    6. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944
   1165    7. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wif-not-aligned
   1166    8. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Common-Variable-Attributes.html#index-warn_005fif_005fnot_005faligned-variable-attribute
   1167    9. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wmissing-attributes
   1168   10. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wpacked-not-aligned
   1169   11. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Warray-bounds
   1170   12. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wrestrict
   1171   13. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-overflow
   1172   14. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Warning-Options.html#index-Wformat-truncation
   1173   15. https://gcc.gnu.org/PR86094
   1174   16. https://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Dialect-Options.html#index-Wclass-memaccess
   1175   17. http://gcc.gnu.org/projects/cxx-status.html#cxx2a
   1176   18. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_vector
   1177   19. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/expressions.html#gcc_jit_context_new_rvalue_from_vector
   1178   20. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/types.html#gcc_jit_type_get_aligned
   1179   21. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/function-pointers.html#gcc_jit_function_get_address
   1180   22. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/jit/topics/contexts.html#gcc_jit_context_dump_reproducer_to_file
   1181   23. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/ARM-Options.html#ARM-Options
   1182   24. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Options.html
   1183   25. https://sourceware.org/PR21472
   1184   26. https://gcc.gnu.org/PR20296
   1185   27. https://sourceware.org/binutils/docs-2.29/as/AVR-Pseudo-Instructions.html
   1186   28. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/AVR-Function-Attributes.html
   1187   29. https://sourceware.org/PR21683
   1188   30. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.0
   1189   31. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.2
   1190   32. https://gcc.gnu.org/PR86094
   1191   33. http://gcc.gnu.org/gcc-8/changes.html#cxx
   1192   34. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84413
   1193   35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.3
   1194   36. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137
   1195   37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=8.4
   1196   38. https://gcc.gnu.org/onlinedocs/
   1197   39. mailto:gcc-help (a] gcc.gnu.org
   1198   40. mailto:gcc (a] gcc.gnu.org
   1199   41. https://gcc.gnu.org/lists.html
   1200   42. https://www.fsf.org/
   1201   43. https://gcc.gnu.org/about.html
   1202   44. http://validator.w3.org/check/referer
   1203 ======================================================================
   1204 http://gcc.gnu.org/gcc-7/index.html
   1205                               GCC 7 Release Series
   1206 
   1207    Nov 14, 2019
   1208 
   1209    The [1]GNU project and the GCC developers are pleased to announce the
   1210    release of GCC 7.5.
   1211 
   1212    This release is a bug-fix release, containing fixes for regressions in
   1213    GCC 7.4 relative to previous releases of GCC.
   1214 
   1215 Release History
   1216 
   1217    GCC 7.5
   1218           Nov 14, 2019 ([2]changes, [3]documentation)
   1219 
   1220    GCC 7.4
   1221           Dec 6, 2018 ([4]changes, [5]documentation)
   1222 
   1223    GCC 7.3
   1224           Jan 25, 2018 ([6]changes, [7]documentation)
   1225 
   1226    GCC 7.2
   1227           Aug 14, 2017 ([8]changes, [9]documentation)
   1228 
   1229    GCC 7.1
   1230           May 2, 2017 ([10]changes, [11]documentation)
   1231 
   1232 References and Acknowledgements
   1233 
   1234    GCC used to stand for the GNU C Compiler, but since the compiler
   1235    supports several other languages aside from C, it now stands for the
   1236    GNU Compiler Collection.
   1237 
   1238    A list of [12]successful builds is updated as new information becomes
   1239    available.
   1240 
   1241    The GCC developers would like to thank the numerous people that have
   1242    contributed new features, improvements, bug fixes, and other changes as
   1243    well as test results to GCC. This [13]amazing group of volunteers is
   1244    what makes GCC successful.
   1245 
   1246    For additional information about GCC please refer to the [14]GCC
   1247    project web site or contact the [15]GCC development mailing list.
   1248 
   1249    To obtain GCC please use [16]our mirror sites or [17]our version
   1250    control system.
   1251 
   1252 
   1253     For questions related to the use of GCC, please consult these web
   1254     pages and the [18]GCC manuals. If that fails, the
   1255     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   1256     web pages and the development of GCC are welcome on our developer
   1257     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   1258     archives.
   1259 
   1260    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   1261    distribution of this entire article is permitted in any medium,
   1262    provided this notice is preserved.
   1263 
   1264    These pages are [23]maintained by the GCC team. Last modified
   1265    2020-01-14[24].
   1266 
   1267 References
   1268 
   1269    1. http://www.gnu.org/
   1270    2. http://gcc.gnu.org/gcc-7/changes.html
   1271    3. http://gcc.gnu.org/onlinedocs/7.5.0/
   1272    4. http://gcc.gnu.org/gcc-7/changes.html
   1273    5. http://gcc.gnu.org/onlinedocs/7.4.0/
   1274    6. http://gcc.gnu.org/gcc-7/changes.html
   1275    7. http://gcc.gnu.org/onlinedocs/7.3.0/
   1276    8. http://gcc.gnu.org/gcc-7/changes.html
   1277    9. http://gcc.gnu.org/onlinedocs/7.2.0/
   1278   10. http://gcc.gnu.org/gcc-7/changes.html
   1279   11. http://gcc.gnu.org/onlinedocs/7.1.0/
   1280   12. http://gcc.gnu.org/gcc-7/buildstat.html
   1281   13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   1282   14. http://gcc.gnu.org/index.html
   1283   15. mailto:gcc (a] gcc.gnu.org
   1284   16. http://gcc.gnu.org/mirrors.html
   1285   17. http://gcc.gnu.org/git.html
   1286   18. https://gcc.gnu.org/onlinedocs/
   1287   19. mailto:gcc-help (a] gcc.gnu.org
   1288   20. mailto:gcc (a] gcc.gnu.org
   1289   21. https://gcc.gnu.org/lists.html
   1290   22. https://www.fsf.org/
   1291   23. https://gcc.gnu.org/about.html
   1292   24. http://validator.w3.org/check/referer
   1293 ======================================================================
   1294 http://gcc.gnu.org/gcc-7/changes.html
   1295                               GCC 7 Release Series
   1296                         Changes, New Features, and Fixes
   1297 
   1298    This page is a brief summary of some of the huge number of improvements
   1299    in GCC 7. For more information, see the [1]Porting to GCC 7 page and
   1300    the [2]full GCC documentation.
   1301 
   1302 Caveats
   1303 
   1304      * GCC now uses [3]LRA (a new local register allocator) by default for
   1305        new targets.
   1306      * The non-standard C++0x type traits has_trivial_default_constructor,
   1307        has_trivial_copy_constructor and has_trivial_copy_assign have been
   1308        removed.
   1309      * The libstdc++ [4]Profile Mode has been deprecated and will be
   1310        removed in a future version.
   1311      * The Cilk+ extensions to the C and C++ languages have been
   1312        deprecated.
   1313      * On ARM targets (arm*-*-*), [5]a bug introduced in GCC 5 that
   1314        affects conformance to the procedure call standard (AAPCS) has been
   1315        fixed. The bug affects some C++ code where class objects are passed
   1316        by value to functions and could result in incorrect or inconsistent
   1317        code being generated. This is an ABI change. If the option -Wpsabi
   1318        is enabled (on by default) the compiler will emit a diagnostic note
   1319        for code that might be affected.
   1320 
   1321 General Optimizer Improvements
   1322 
   1323      * GCC 7 can determine the return value or range of return values of
   1324        some calls to the sprintf family of functions and make it available
   1325        to other optimization passes. Some calls to the snprintf function
   1326        with a zero size argument can be folded into constants. This
   1327        optimization is included in -O1 and can be selectively controlled
   1328        by the -fprintf-return-value option.
   1329      * A new store merging pass has been added. It merges constant stores
   1330        to adjacent memory locations into fewer, wider, stores. It is
   1331        enabled by the -fstore-merging option and at the -O2 optimization
   1332        level or higher (and -Os).
   1333      * A new code hoisting optimization has been added to the partial
   1334        redundancy elimination pass. It attempts to move evaluation of
   1335        expressions executed on all paths to the function exit as early as
   1336        possible. This primarily helps improve code size, but can improve
   1337        the speed of the generated code as well. It is enabled by the
   1338        -fcode-hoisting option and at the -O2 optimization level or higher
   1339        (and -Os).
   1340      * A new interprocedural bitwise constant propagation optimization has
   1341        been added, which propagates knowledge about which bits of
   1342        variables are known to be zero (including pointer alignment
   1343        information) across the call graph. It is enabled by the
   1344        -fipa-bit-cp option if -fipa-cp is enabled as well, and is enabled
   1345        at the -O2 optimization level and higher (and -Os). This
   1346        optimization supersedes interprocedural alignment propagation of
   1347        GCC 6, and therefore the option -fipa-cp-alignment is now
   1348        deprecated and ignored.
   1349      * A new interprocedural value range propagation optimization has been
   1350        added, which propagates integral range information across the call
   1351        graph when variable values can be proven to be within those ranges.
   1352        It is enabled by the -fipa-vrp option and at the -O2 optimization
   1353        level and higher (and -Os).
   1354      * A new loop splitting optimization pass has been added. Certain
   1355        loops which contain a condition that is always true on one side of
   1356        the iteration space and always false on the other are split into
   1357        two loops, such that each of the two new loops iterates on just one
   1358        side of the iteration space and the condition does not need to be
   1359        checked inside of the loop. It is enabled by the -fsplit-loops
   1360        option and at the -O3 optimization level or higher.
   1361      * The shrink-wrapping optimization can now separate portions of
   1362        prologues and epilogues to improve performance if some of the work
   1363        done traditionally by prologues and epilogues is not needed on
   1364        certain paths. This is controlled by the -fshrink-wrap-separate
   1365        option, enabled by default. It requires target support, which is
   1366        currently only implemented in the PowerPC and AArch64 ports.
   1367      * AddressSanitizer gained a new sanitization option,
   1368        -fsanitize-address-use-after-scope, which enables sanitization of
   1369        variables whose address is taken and used after a scope where the
   1370        variable is defined:
   1371 
   1372 int
   1373 main (int argc, char **argv)
   1374 {
   1375   char *ptr;
   1376     {
   1377       char my_char;
   1378       ptr = &my_char;
   1379     }
   1380 
   1381   *ptr = 123;
   1382   return *ptr;
   1383 }
   1384 
   1385 ==28882==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7fffb8dba99
   1386 0 at pc 0x0000004006d5 bp 0x7fffb8dba960 sp 0x7fffb8dba958
   1387 WRITE of size 1 at 0x7fffb8dba990 thread T0
   1388     #0 0x4006d4 in main /tmp/use-after-scope-1.c:10
   1389     #1 0x7f9c71943290 in __libc_start_main (/lib64/libc.so.6+0x20290)
   1390     #2 0x400739 in _start (/tmp/a.out+0x400739)
   1391 
   1392 Address 0x7fffb8dba990 is located in stack of thread T0 at offset 32 in frame
   1393     #0 0x40067f in main /tmp/use-after-scope-1.c:3
   1394 
   1395   This frame has 1 object(s):
   1396     [32, 33) 'my_char' <== Memory access at offset 32 is inside this variable
   1397 
   1398        The option is enabled by default with -fsanitize=address and
   1399        disabled by default with -fsanitize=kernel-address. Compared to the
   1400        LLVM compiler, where the option already exists, the implementation
   1401        in the GCC compiler has some improvements and advantages:
   1402           + Complex uses of gotos and case labels are properly handled and
   1403             should not report any false positive or false negatives.
   1404           + C++ temporaries are sanitized.
   1405           + Sanitization can handle invalid memory stores that are
   1406             optimized out by the LLVM compiler when optimization is
   1407             enabled.
   1408      * The -fsanitize=signed-integer-overflow suboption of the
   1409        UndefinedBehavior Sanitizer now diagnoses arithmetic overflows even
   1410        on arithmetic operations with generic vectors.
   1411      * Version 5 of the [6]DWARF debugging information standard is
   1412        supported through the -gdwarf-5 option. The DWARF version 4
   1413        debugging information remains the default until consumers of
   1414        debugging information are adjusted.
   1415 
   1416 New Languages and Language specific improvements
   1417 
   1418    OpenACC support in C, C++, and Fortran continues to be maintained and
   1419    improved. See the [7]OpenACC and [8]Offloading wiki pages for further
   1420    information.
   1421 
   1422   Ada
   1423 
   1424      * On mainstream native platforms, Ada programs no longer require the
   1425        stack to be made executable in order to run properly.
   1426 
   1427   BRIG (HSAIL)
   1428 
   1429    Support for processing BRIG 1.0 files was added in this release. BRIG
   1430    is a binary format for HSAIL (Heterogeneous System Architecture
   1431    Intermediate Language). The BRIG front end can be used for implementing
   1432    HSAIL "finalizers" (compilation of HSAIL to a native ISA) for
   1433    GCC-supported targets. An implementation of an HSAIL runtime library,
   1434    libhsail-rt is also included.
   1435 
   1436   C family
   1437 
   1438      * New command-line options have been added for the C and C++
   1439        compilers:
   1440           + -Wimplicit-fallthrough warns when a switch case falls through.
   1441             This warning has five different levels. The compiler is able
   1442             to parse a wide range of fallthrough comments, depending on
   1443             the level. It also handles control-flow statements, such as
   1444             ifs. It's possible to suppress the warning by either adding a
   1445             fallthrough comment, or by using a null statement:
   1446             __attribute__ ((fallthrough)); (C, C++), or [[fallthrough]];
   1447             (C++17), or [[gnu::fallthrough]]; (C++11/C++14). This warning
   1448             is enabled by -Wextra.
   1449           + -Wpointer-compare warns when a pointer is compared with a zero
   1450             character constant. Such code is now invalid in C++11 and GCC
   1451             rejects it. This warning is enabled by default.
   1452           + -Wduplicated-branches warns when an if-else has identical
   1453             branches.
   1454           + -Wrestrict warns when an argument passed to a
   1455             restrict-qualified parameter aliases with another argument.
   1456           + -Wmemset-elt-size warns for memset calls, when the first
   1457             argument references an array, and the third argument is a
   1458             number equal to the number of elements of the array, but not
   1459             the size of the array. This warning is enabled by -Wall.
   1460           + -Wint-in-bool-context warns about suspicious uses of integer
   1461             values where boolean values are expected. This warning is
   1462             enabled by -Wall.
   1463           + -Wswitch-unreachable warns when a switch statement has
   1464             statements between the controlling expression and the first
   1465             case label which will never be executed. This warning is
   1466             enabled by default.
   1467           + -Wexpansion-to-defined warns when defined is used outside #if.
   1468             This warning is enabled by -Wextra or -Wpedantic.
   1469           + -Wregister warns about uses of the register storage specifier.
   1470             In C++17 this keyword has been removed and for C++17 this is a
   1471             pedantic warning enabled by default. The warning is not
   1472             emitted for the GNU Explicit Register Variables extension.
   1473           + -Wvla-larger-than=N warns about unbounded uses of
   1474             variable-length arrays, and about bounded uses of
   1475             variable-length arrays whose bound can be larger than N bytes.
   1476           + -Wduplicate-decl-specifier warns when a declaration has
   1477             duplicate const, volatile, restrict or _Atomic specifier. This
   1478             warning is enabled by -Wall.
   1479      * GCC 6's C and C++ front ends were able to offer suggestions for
   1480        misspelled field names:
   1481 
   1482 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did
   1483 you mean 'color'?
   1484    return ptr->colour;
   1485                ^~~~~~
   1486 
   1487        GCC 7 greatly expands the scope of these suggestions. Firstly, it
   1488        adds fix-it hints to such suggestions:
   1489 
   1490 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did
   1491 you mean 'color'?
   1492    return ptr->colour;
   1493                ^~~~~~
   1494                color
   1495 
   1496        The suggestions now cover many other things, such as misspelled
   1497        function names:
   1498 
   1499 spellcheck-identifiers.c:11:3: warning: implicit declaration of function 'gtk_wi
   1500 dget_showall'; did you mean 'gtk_widget_show_all'? [-Wimplicit-function-declarat
   1501 ion]
   1502    gtk_widget_showall (w);
   1503    ^~~~~~~~~~~~~~~~~~
   1504    gtk_widget_show_all
   1505 
   1506        misspelled macro names and enum values:
   1507 
   1508 spellcheck-identifiers.cc:85:11: error: 'MAX_ITEM' undeclared here (not in a fun
   1509 ction); did you mean 'MAX_ITEMS'?
   1510  int array[MAX_ITEM];
   1511            ^~~~~~~~
   1512            MAX_ITEMS
   1513 
   1514        misspelled type names:
   1515 
   1516 spellcheck-typenames.c:7:14: error: unknown type name 'singed'; did you mean 'si
   1517 gned'?
   1518  void test (singed char e);
   1519             ^~~~~~
   1520             signed
   1521 
   1522        and, in the C front end, named initializers:
   1523 
   1524 test.c:7:20: error: 'struct s' has no member named 'colour'; did you mean 'color
   1525 '?
   1526  struct s test = { .colour = 3 };
   1527                     ^~~~~~
   1528                     color
   1529 
   1530      * The preprocessor can now offer suggestions for misspelled
   1531        directives, e.g.:
   1532 
   1533 test.c:5:2: error:invalid preprocessing directive #endfi; did you mean #endif?
   1534  #endfi
   1535   ^~~~~
   1536   endif
   1537 
   1538      * Warnings about format strings now underline the pertinent part of
   1539        the string, and can offer suggested fixes. In some cases, the
   1540        pertinent argument is underlined.
   1541 
   1542 test.c:51:29: warning: format '%s' expects argument of type 'char *', but argume
   1543 nt 3 has type 'int' [-Wformat=]
   1544    printf ("foo: %d  bar: %s baz: %d", 100, i + j, 102);
   1545                           ~^                ~~~~~
   1546                           %d
   1547 
   1548      * The new -Wdangling-else command-line option has been split out of
   1549        -Wparentheses and warns about dangling else.
   1550      * The -Wshadow warning has been split into three variants.
   1551        -Wshadow=global warns for any shadowing. This is the default when
   1552        using -Wshadow without any argument. -Wshadow=local only warns for
   1553        a local variable shadowing another local variable or parameter.
   1554        -Wshadow=compatible-local only warns for a local variable shadowing
   1555        another local variable or parameter whose type is compatible (in
   1556        C++ compatible means that the type of the shadowing variable can be
   1557        converted to that of the shadowed variable).
   1558        The following example shows the different kinds of shadow warnings:
   1559 
   1560 enum operation { add, count };
   1561 struct container { int nr; };
   1562 
   1563 int
   1564 container_count (struct container c, int count)
   1565 {
   1566   int r = 0;
   1567   for (int count = 0; count > 0; count--)
   1568     {
   1569       struct container count = c;
   1570       r += count.nr;
   1571     }
   1572   return r;
   1573 }
   1574 
   1575        -Wshadow=compatible-local will warn for the parameter being
   1576        shadowed with the same type:
   1577 
   1578 warn-test.c:8:12: warning: declaration of 'count' shadows a parameter [-Wshadow=
   1579 compatible-local]
   1580    for (int count = 0; count > 0; count--)
   1581             ^~~~~
   1582 warn-test.c:5:42: note: shadowed declaration is here
   1583  container_count (struct container c, int count)
   1584                                           ^~~~~
   1585 
   1586        -Wshadow=local will warn for the above and for the shadowed
   1587        declaration with incompatible type:
   1588 
   1589 warn-test.c:10:24: warning: declaration of 'count' shadows a previous local [-Ws
   1590 hadow=local]
   1591        struct container count = c;
   1592                         ^~~~~
   1593 warn-test.c:8:12: note: shadowed declaration is here
   1594    for (int count = 0; count > 0; count--)
   1595             ^~~~~
   1596 
   1597        -Wshadow=global will warn for all of the above and the shadowing of
   1598        the global declaration:
   1599 
   1600 warn-test.c:5:42: warning: declaration of 'count' shadows a global declaration [
   1601 -Wshadow]
   1602  container_count (struct container c, int count)
   1603                                           ^~~~~
   1604 warn-test.c:1:23: note: shadowed declaration is here
   1605  enum operation { add, count };
   1606                        ^~~~~
   1607 
   1608      * GCC 7 contains a number of enhancements that help detect buffer
   1609        overflow and other forms of invalid memory accesses.
   1610           + The -Walloc-size-larger-than=size option detects calls to
   1611             standard and user-defined memory allocation functions
   1612             decorated with attribute alloc_size whose argument exceeds the
   1613             specified size (PTRDIFF_MAX by default). The option also
   1614             detects arithmetic overflow in the computation of the size in
   1615             two-argument allocation functions like calloc where the total
   1616             size is the product of the two arguments. Since calls with an
   1617             excessive size cannot succeed they are typically the result of
   1618             programming errors. Such bugs have been known to be the source
   1619             of security vulnerabilities and a target of exploits.
   1620             -Walloc-size-larger-than=PTRDIFF_MAX is included in -Wall.
   1621             For example, the following call to malloc incorrectly tries to
   1622             avoid passing a negative argument to the function and instead
   1623             ends up unconditionally invoking it with an argument less than
   1624             or equal to zero. Since after conversion to the type of the
   1625             argument of the function (size_t) a negative argument results
   1626             in a value in excess of the maximum PTRDIFF_MAX the call is
   1627             diagnosed.
   1628 
   1629 void* f (int n)
   1630 {
   1631   return malloc (n > 0 ? 0 : n);
   1632 }
   1633 
   1634 warning: argument 1 range [2147483648, 4294967295] exceeds maximum object size 2
   1635 147483647 [-Walloc-size-larger-than=]
   1636 
   1637           + The -Walloc-zero option detects calls to standard and
   1638             user-defined memory allocation functions decorated with
   1639             attribute alloc_size with a zero argument. -Walloc-zero is not
   1640             included in either -Wall or -Wextra and must be explicitly
   1641             enabled.
   1642           + The -Walloca option detects all calls to the alloca function
   1643             in the program. -Walloca is not included in either -Wall or
   1644             -Wextra and must be explicitly enabled.
   1645           + The -Walloca-larger-than=size option detects calls to the
   1646             alloca function whose argument either may exceed the specified
   1647             size, or that is not known to be sufficiently constrained to
   1648             avoid exceeding it. -Walloca-larger-than is not included in
   1649             either -Wall or -Wextra and must be explicitly enabled.
   1650             For example, compiling the following snippet with
   1651             -Walloca-larger-than=1024 results in a warning because even
   1652             though the code appears to call alloca only with sizes of 1kb
   1653             and less, since n is signed, a negative value would result in
   1654             a call to the function well in excess of the limit.
   1655 
   1656 void f (int n)
   1657 {
   1658   char *d;
   1659   if (n < 1025)
   1660     d = alloca (n);
   1661   else
   1662     d = malloc (n);
   1663   
   1664 }
   1665 
   1666 warning: argument to 'alloca may be too large due to conversion from 'int' to 'l
   1667 ong unsigned int' [-Walloca-larger-than=]
   1668 
   1669             In contrast, a call to alloca that isn't bounded at all such
   1670             as in the following function will elicit the warning below
   1671             regardless of the size argument to the option.
   1672 
   1673 void f (size_t n)
   1674 {
   1675   char *d = alloca (n);
   1676   
   1677 }
   1678 
   1679 warning: unbounded use of 'alloca' [-Walloca-larger-than=]
   1680 
   1681           + The -Wformat-overflow=level option detects certain and likely
   1682             buffer overflow in calls to the sprintf family of formatted
   1683             output functions. Although the option is enabled even without
   1684             optimization it works best with -O2 and higher.
   1685             For example, in the following snippet the call to sprintf is
   1686             diagnosed because even though its output has been constrained
   1687             using the modulo operation it could result in as many as three
   1688             bytes if mday were negative. The solution is to either
   1689             allocate a larger buffer or make sure the argument is not
   1690             negative, for example by changing mday's type to unsigned or
   1691             by making the type of the second operand of the modulo
   1692             expression unsigned: 100U.
   1693 
   1694 void* f (int mday)
   1695 {
   1696   char *buf = malloc (3);
   1697   sprintf (buf, "%02i", mday % 100);
   1698   return buf;
   1699 }
   1700 
   1701 warning: 'sprintf may write a terminating nul past the end of the destination [-
   1702 Wformat-overflow=]
   1703 note: 'sprintf' output between 3 and 4 bytes into a destination of size 3
   1704 
   1705           + The -Wformat-truncation=level option detects certain and
   1706             likely output truncation in calls to the snprintf family of
   1707             formatted output functions. -Wformat-truncation=1 is included
   1708             in -Wall and enabled without optimization but works best with
   1709             -O2 and higher.
   1710             For example, the following function attempts to format an
   1711             integer between 0 and 255 in hexadecimal, including the 0x
   1712             prefix, into a buffer of four characters. But since the
   1713             function must always terminate output by the null character
   1714             ('\0') such a buffer is only big enough to fit just one digit
   1715             plus the prefix. Therefore the snprintf call is diagnosed. To
   1716             avoid the warning either use a bigger buffer or handle the
   1717             function's return value which indicates whether or not its
   1718             output has been truncated.
   1719 
   1720 void f (unsigned x)
   1721 {
   1722   char d[4];
   1723   snprintf (d, sizeof d, "%#02x", x & 0xff);
   1724   
   1725 }
   1726 
   1727 warning: 'snprintf' output may be truncated before the last format character [-W
   1728 format-truncation=]
   1729 note: 'snprintf' output between 3 and 5 bytes into a destination of size 4
   1730 
   1731           + The -Wnonnull option has been enhanced to detect a broader set
   1732             of cases of passing null pointers to functions that expect a
   1733             non-null argument (those decorated with attribute nonnull). By
   1734             taking advantage of optimizations the option can detect many
   1735             more cases of the problem than in prior GCC versions.
   1736           + The -Wstringop-overflow=type option detects buffer overflow in
   1737             calls to string handling functions like memcpy and strcpy. The
   1738             option relies on [9]Object Size Checking and has an effect
   1739             similar to defining the _FORTIFY_SOURCE macro.
   1740             -Wstringop-overflow=2 is enabled by default.
   1741             For example, in the following snippet, because the call to
   1742             strncat specifies a maximum that allows the function to write
   1743             past the end of the destination, it is diagnosed. To correct
   1744             the problem and avoid the overflow the function should be
   1745             called with a size of at most sizeof d - strlen(d) - 1.
   1746 
   1747 void f (const char *fname)
   1748 {
   1749   char d[8];
   1750   strncpy (d, "/tmp/", sizeof d);
   1751   strncat (d, fname, sizeof d);
   1752   
   1753 }
   1754 
   1755 warning: specified bound 8 equals the size of the destination [-Wstringop-overfl
   1756 ow=]
   1757 
   1758      * The <limits.h> header provided by GCC defines macros such as
   1759        INT_WIDTH for the width in bits of integer types, if
   1760        __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is
   1761        included. The <stdint.h> header defines such macros as SIZE_WIDTH
   1762        and INTMAX_WIDTH for the width of some standard typedef names for
   1763        integer types, again if __STDC_WANT_IEC_60559_BFP_EXT__ is defined
   1764        before the header is included; note that GCC's implementation of
   1765        this header is only used for freestanding compilations, not hosted
   1766        compilations, on most systems. These macros come from ISO/IEC TS
   1767        18661-1:2014.
   1768      * The <float.h> header provided by GCC defines the macro
   1769        CR_DECIMAL_DIG, from ISO/IEC TS 18661-1:2014, if
   1770        __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the header is
   1771        included. This represents the number of decimal digits for which
   1772        conversions between decimal character strings and binary formats,
   1773        in both directions, are correctly rounded, and currently has the
   1774        value of UINTMAX_MAX on all systems, reflecting that GCC's
   1775        compile-time conversions are correctly rounded for any number of
   1776        digits.
   1777      * New __builtin_add_overflow_p, __builtin_sub_overflow_p,
   1778        __builtin_mul_overflow_p built-in functions have been added. These
   1779        work similarly to their siblings without the _p suffix, but do not
   1780        actually store the result of the arithmetics anywhere, just return
   1781        whether the operation would overflow. Calls to these built-ins with
   1782        integer constant arguments evaluate to integer constants
   1783        expressions.
   1784        For example, in the following, c is assigned the result of a * b
   1785        only if the multiplication does not overflow, otherwise it is
   1786        assigned the value zero. The multiplication is performed at
   1787        compile-time and without triggering a -Woverflow warning.
   1788 
   1789 enum {
   1790   a = 12345678,
   1791   b = 87654321,
   1792   c = __builtin_mul_overflow_p (a, b, a) ? 0 : a * b
   1793 };
   1794 
   1795   C
   1796 
   1797      * The C front end now supports type names _FloatN for floating-point
   1798        types with IEEE interchange formats and _FloatNx for floating-point
   1799        types with IEEE extended formats. These type names come from
   1800        ISO/IEC TS 18661-3:2015.
   1801        The set of types supported depends on the target for which GCC is
   1802        configured. Most targets support _Float32, _Float32x and _Float64.
   1803        _Float128 is supported on targets where IEEE binary128 encoding was
   1804        already supported as long double or __float128. _Float64x is
   1805        supported on targets where a type with either binary128 or Intel
   1806        extended precision format is available.
   1807        Constants with these types are supported using suffixes fN, FN, fNx
   1808        and FNx (e.g., 1.2f128 or 2.3F64x). Macros such as FLT128_MAX are
   1809        defined in <float.h> if __STDC_WANT_IEC_60559_TYPES_EXT__ is
   1810        defined before it is included.
   1811        These new types are always distinct from each other and from float,
   1812        double and long double, even if they have the same encoding.
   1813        Complex types such as _Complex _Float128 are also supported.
   1814        Type-generic built-in functions such as __builtin_isinf support the
   1815        new types, and the following type-specific built-in functions have
   1816        versions (suffixed fN or fNx) for the new types:
   1817        __builtin_copysign, __builtin_fabs, __builtin_huge_val,
   1818        __builtin_inf, __builtin_nan, __builtin_nans.
   1819      * Compilation with -fopenmp is now compatible with the C11 _Atomic
   1820        keyword.
   1821 
   1822   C++
   1823 
   1824      * The C++ front end has experimental support for all of the current
   1825        C++17 draft with the -std=c++1z or -std=gnu++1z flags, including if
   1826        constexpr, class template argument deduction, auto template
   1827        parameters, and structured bindings. For a full list of new
   1828        features, see [10]the C++ status page.
   1829      * C++17 support for new of over-aligned types can be enabled in other
   1830        modes with the -faligned-new flag.
   1831      * The C++17 evaluation order requirements can be selected in other
   1832        modes with the -fstrong-eval-order flag, or disabled in C++17 mode
   1833        with -fno-strong-eval-order.
   1834      * The default semantics of inherited constructors has changed in all
   1835        modes, following [11]P0136. Essentially, overload resolution
   1836        happens as if calling the inherited constructor directly, and the
   1837        compiler fills in construction of the other bases and members as
   1838        needed. Most uses should not need any changes. The old behavior can
   1839        be restored with -fno-new-inheriting-ctors, or -fabi-version less
   1840        than 11.
   1841      * The resolution of DR 150 on matching of template template
   1842        parameters, allowing default template arguments to make a template
   1843        match a parameter, is currently enabled by default in C++17 mode
   1844        only. The default can be overridden with -f{no-,}new-ttp-matching.
   1845      * The C++ front end will now provide fix-it hints for some missing
   1846        semicolons, allowing for automatic fixes by IDEs:
   1847 
   1848 test.cc:4:11: error: expected ';' after class definition
   1849  class a {}
   1850            ^
   1851            ;
   1852 
   1853      * -Waligned-new has been added to the C++ front end. It warns about
   1854        new of type with extended alignment without -faligned-new.
   1855 
   1856     Runtime Library (libstdc++)
   1857 
   1858      * The type of exception thrown by iostreams, std::ios_base::failure,
   1859        now uses the [12]cxx11 ABI.
   1860      * Experimental support for C++17, including the following new
   1861        features:
   1862           + std::string_view;
   1863           + std::any, std::optional, and std::variant;
   1864           + std::invoke, std::is_invocable, std::is_nothrow_invocable, and
   1865             invoke_result;
   1866           + std::is_swappable, and std::is_nothrow_swappable;
   1867           + std::apply, and std::make_from_tuple;
   1868           + std::void_t, std::bool_constant, std::conjunction,
   1869             std::disjunction, and std::negation;
   1870           + Variable templates for type traits;
   1871           + Mathematical Special Functions;
   1872           + std::chrono::floor, std::chrono::ceil, std::chrono::round, and
   1873             std::chrono::abs;
   1874           + std::clamp, std::gcd, std::lcm, 3-dimensional std::hypot;
   1875           + std::scoped_lock, std::shared_mutex,
   1876             std::atomic<T>::is_always_lock_free;
   1877           + std::sample, std::default_searcher, std::boyer_moore_searcher
   1878             and std::boyer_moore_horspool_searcher;
   1879           + Extraction and re-insertion of map and set nodes, try_emplace
   1880             members for maps, and functions for accessing containers
   1881             std::size, std::empty, and std::data;
   1882           + std::shared_ptr support for arrays,
   1883             std::shared_ptr<T>::weak_type,
   1884             std::enable_shared_from_this<T>::weak_from_this(), and
   1885             std::owner_less<void>;
   1886           + std::byte;
   1887           + std::as_const, std::not_fn,
   1888             std::has_unique_object_representations, constexpr
   1889             std::addressof.
   1890        Thanks to Daniel Krgler, Tim Shen, Edward Smith-Rowland, and Ville
   1891        Voutilainen for work on the C++17 support.
   1892      * A new power-of-two rehashing policy for use with the _Hashtable
   1893        internals, thanks to Franois Dumont.
   1894 
   1895   Fortran
   1896 
   1897      * Support for a number of extensions for compatibility with legacy
   1898        code with new flags:
   1899           + -fdec-structure Support for DEC STRUCTURE and UNION
   1900           + -fdec-intrinsic-ints Support for new integer intrinsics with
   1901             B/I/J/K prefixes such as BABS, JIAND...
   1902           + -fdec-math Support for additional math intrinsics, including
   1903             COTAN and degree-valued trigonometric functions such as TAND,
   1904             ASIND...
   1905           + -fdec Enable the -fdec-* family of extensions.
   1906      * New flag -finit-derived to allow default initialization of
   1907        derived-type variables.
   1908      * Improved DO loops with step equal to 1 or -1, generates faster code
   1909        without a loop preheader. A new warning, -Wundefined-do-loop, warns
   1910        when a loop iterates either to HUGE(i) (with step equal to 1), or
   1911        to -HUGE(i) (with step equal to -1). Invalid behavior can be caught
   1912        at run time with -fcheck=do enabled:
   1913 
   1914 program test
   1915   implicit none
   1916   integer(1) :: i
   1917   do i = -HUGE(i)+10, -HUGE(i)-1, -1
   1918     print *, i
   1919   end do
   1920 end program test
   1921 
   1922 At line 8 of file do_check_12.f90
   1923 Fortran runtime error: Loop iterates infinitely
   1924 
   1925      * Version 4.5 of the [13]OpenMP specification is now partially
   1926        supported in the Fortran compiler; the largest missing item is
   1927        structure element mapping.
   1928      * User-defined derived-type input/output (UDTIO) is added.
   1929      * Derived type coarrays with allocatable and pointer components are
   1930        partially supported.
   1931      * Non-constant stop codes and error stop codes (Fortran 2015
   1932        feature).
   1933      * Derived types with allocatable components of recursive type.
   1934      * Intrinsic assignment to polymorphic variables.
   1935      * Improved submodule support.
   1936      * Improved diagnostics (polymorphic results in pure functions).
   1937      * Coarray: Support for failed images (Fortan 2015 feature).
   1938 
   1939   Go
   1940 
   1941      * GCC 7 provides a complete implementation of the Go 1.8.1 user
   1942        packages.
   1943      * Compared to the Go 1.8.1 toolchain, the garbage collector is more
   1944        conservative and less concurrent.
   1945      * Escape analysis is available for experimental use via the
   1946        -fgo-optimize-allocs option. The -fgo-debug-escape prints
   1947        information useful for debugging escape analysis choices.
   1948 
   1949   Java (GCJ)
   1950 
   1951    The GCC Java front end and associated libjava runtime library have been
   1952    removed from GCC.
   1953 
   1954 libgccjit
   1955 
   1956    The libgccjit API gained support for marking calls as requiring
   1957    tail-call optimization via a new entry point:
   1958    [14]gcc_jit_rvalue_set_bool_require_tail_call.
   1959 
   1960    libgccjit performs numerous checks at the API boundary, but if these
   1961    succeed, it previously ignored errors and other diagnostics emitted
   1962    within the core of GCC, and treated the compile of a gcc_jit_context as
   1963    having succeeded. As of GCC 7 it now ensures that if any diagnostics
   1964    are emitted, they are visible from the libgccjit API, and that the the
   1965    context is flagged as having failed.
   1966 
   1967 New Targets and Target Specific Improvements
   1968 
   1969   AArch64
   1970 
   1971      * GCC has been updated to the latest revision of the procedure call
   1972        standard (AAPCS64) to provide support for parameter passing when
   1973        data types have been over-aligned.
   1974      * The ARMv8.3-A architecture is now supported. It can be used by
   1975        specifying the -march=armv8.3-a option.
   1976      * The option -msign-return-address= is supported to enable return
   1977        address protection using ARMv8.3-A Pointer Authentication
   1978        Extensions. For more information on the arguments accepted by this
   1979        option, please refer to [15]AArch64-Options.
   1980      * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point
   1981        Extensions are now supported. They can be used by specifying the
   1982        -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit
   1983        Floating-Point Extensions introduce new half-precision data
   1984        processing floating-point instructions.
   1985      * Support has been added for the following processors (GCC
   1986        identifiers in parentheses): ARM Cortex-A73 (cortex-a73), Broadcom
   1987        Vulcan (vulcan), Cavium ThunderX CN81xx (thunderxt81), Cavium
   1988        ThunderX CN83xx (thunderxt83), Cavium ThunderX CN88xx
   1989        (thunderxt88), Cavium ThunderX CN88xx pass 1.x (thunderxt88p1),
   1990        Cavium ThunderX 2 CN99xx (thunderx2t99), Qualcomm Falkor (falkor).
   1991        The GCC identifiers can be used as arguments to the -mcpu or -mtune
   1992        options, for example: -mcpu=cortex-a73 or -mtune=vulcan or as
   1993        arguments to the equivalent target attributes and pragmas.
   1994 
   1995   ARC
   1996 
   1997      * Added support for ARC HS and ARC EM processors.
   1998      * Added support for ARC EM variation found in Intel QuarkSE SoCs.
   1999      * Added support for NPS400 ARC700 based CPUs.
   2000      * Thread Local Storage is now supported by ARC CPUs.
   2001      * Fixed errors for ARC600 when using 32x16 multiplier option.
   2002      * Fixed PIE for ARC CPUs.
   2003      * New CPU templates are supported via multilib.
   2004 
   2005   ARM
   2006 
   2007      * Support for the ARMv5 and ARMv5E architectures has been deprecated
   2008        (which have no known implementations) and will be removed in a
   2009        future GCC release. Note that ARMv5T, ARMv5TE and ARMv5TEJ
   2010        architectures remain supported. The values armv5 and armv5e of
   2011        -march are thus deprecated.
   2012      * The ARMv8.2-A architecture and the ARMv8.2-A 16-bit Floating-Point
   2013        Extensions are now supported. They can be used by specifying the
   2014        -march=armv8.2-a or -march=armv8.2-a+fp16 options. The 16-bit
   2015        Floating-Point Extensions introduce new half-precision data
   2016        processing floating-point instructions.
   2017      * The ARMv8-M architecture is now supported in its two architecture
   2018        profiles: ARMv8-M Baseline and ARMv8-M Mainline with its DSP and
   2019        Floating-Point Extensions. They can be used by specifying the
   2020        -march=armv8-m.base, armv8-m.main or armv8-m.main+dsp options.
   2021      * Support has been added for the following processors (GCC
   2022        identifiers in parentheses): ARM Cortex-A73 (cortex-a73), ARM
   2023        Cortex-M23 (cortex-m23) and ARM Cortex-M33 (cortex-m33). The GCC
   2024        identifiers can be used as arguments to the -mcpu or -mtune
   2025        options, for example: -mcpu=cortex-a73 or -mtune=cortex-m33.
   2026      * A new command-line option -mpure-code has been added. It does not
   2027        allow constant data to be placed in code sections. This option is
   2028        only available when generating non-PIC code for ARMv7-M targets.
   2029      * Support for the ACLE Coprocessor Intrinsics has been added. This
   2030        enables the generation of coprocessor instructions through the use
   2031        of intrinsics such as cdp, ldc, and others.
   2032      * The configure option --with-multilib-list now accepts the value
   2033        rmprofile to build multilib libraries for a range of embedded
   2034        targets. See our [16]installation instructions for details.
   2035 
   2036   AVR
   2037 
   2038      * On the reduced Tiny cores, the progmem [17]variable attribute is
   2039        now properly supported. Respective read-only variables are located
   2040        in flash memory in section .progmem.data. No special code is needed
   2041        to access such variables; the compiler automatically adds an offset
   2042        of 0x4000 to all addresses, which is needed to access variables in
   2043        flash memory. As opposed to ordinary cores where it is sufficient
   2044        to specify the progmem attribute with definitions, on the reduced
   2045        Tiny cores the attribute also has to be specified with (external)
   2046        declarations:
   2047 
   2048 extern const int array[] __attribute__((__progmem__));
   2049 
   2050 int get_value2 (void)
   2051 {
   2052   /* Access via addresses array + 0x4004 and array + 0x4005. */
   2053   return array[2];
   2054 }
   2055 
   2056 const int* get_address (unsigned idx)
   2057 {
   2058   /* Returns array + 0x4000 + 2 * idx. */
   2059   return &array[idx];
   2060 }
   2061 
   2062      * A new command-line option -Wmisspelled-isr has been added. It turns
   2063        off  or turns into errors  warnings that are reported for
   2064        interrupt service routines (ISRs) which don't follow AVR-LibC's
   2065        naming convention of prefixing ISR names with __vector.
   2066      * __builtin_avr_nops(n) is a new [18]built-in function that inserts n
   2067        NOP instructions into the instruction stream. n must be a value
   2068        known at compile time.
   2069 
   2070   IA-32/x86-64
   2071 
   2072      * Support for the AVX-512 Fused Multiply Accumulation Packed Single
   2073        precision (4FMAPS), AVX-512 Vector Neural Network Instructions Word
   2074        variable precision (4VNNIW), AVX-512 Vector Population Count
   2075        (VPOPCNTDQ) and Software Guard Extensions (SGX) ISA extensions has
   2076        been added.
   2077 
   2078   NVPTX
   2079 
   2080      * OpenMP target regions can now be offloaded to NVidia PTX GPGPUs.
   2081        See the [19]Offloading Wiki on how to configure it.
   2082 
   2083   PowerPC / PowerPC64 / RS6000
   2084 
   2085      * The PowerPC port now uses LRA by default.
   2086      * GCC now diagnoses inline assembly that clobbers register r2. This
   2087        has always been invalid code, and is no longer quietly tolerated.
   2088      * The PowerPC port's support for ISA 3.0 (-mcpu=power9) has been
   2089        enhanced to generate more of the new instructions by default, and
   2090        to provide more built-in functions to generate code for other new
   2091        instructions.
   2092      * The configuration option --enable-gnu-indirect-function is now
   2093        enabled by default on PowerPC GNU/Linux builds.
   2094      * The PowerPC port will now allow 64-bit and 32-bit integer types to
   2095        be allocated to the VSX vector registers (ISA 2.06 and above). In
   2096        addition, on ISA 3.0, 16-bit and 8-bit integer types can be
   2097        allocated in the vector registers. Previously, only 64-bit integer
   2098        types were allowed in the traditional floating point registers.
   2099      * New options -mstack-protector-guard=global,
   2100        -mstack-protector-guard=tls, -mstack-protector-guard-reg=, and
   2101        -mstack-protector-guard-offset= change how the stack protector gets
   2102        the value to use as canary.
   2103 
   2104   S/390, System z, IBM z Systems, IBM Z
   2105 
   2106      * Support for the IBM z14 processor has been added. When using the
   2107        -march=z14 option, the compiler will generate code making use of
   2108        the new instructions introduced with the vector enhancement
   2109        facility and the miscellaneous instruction extension facility 2.
   2110        The -mtune=z14 option enables z14 specific instruction scheduling
   2111        without making use of new instructions.
   2112      * Builtins for the new vector instructions have been added and can be
   2113        enabled using the -mzvector option.
   2114 
   2115   RISC-V
   2116 
   2117      * Support for the RISC-V instruction set has been added.
   2118 
   2119   RX
   2120 
   2121    Basic support for atomic built-in function has been added. It is
   2122    currently implemented by flipping interrupts off and on as needed.
   2123 
   2124   SH
   2125 
   2126      * Support for SH5/SH64 has been removed.
   2127      * Improved utilization of delay slots on SH2A.
   2128      * Improved utilization of zero-displacement conditional branches.
   2129      * The following deprecated options have been removed
   2130           + -mcbranchdi
   2131           + -mcmpeqdi
   2132           + -minvalid-symbols
   2133           + -msoft-atomic
   2134           + -mspace
   2135           + -madjust-unroll
   2136      * Support for the following SH2A instructions has been added
   2137           + mov.b @-Rm,R0
   2138           + mov.w @-Rm,R0
   2139           + mov.l @-Rm,R0
   2140           + mov.b R0,@Rn+
   2141           + mov.w R0,@Rn+
   2142           + mov.l R0,@Rn+
   2143 
   2144   SPARC
   2145 
   2146      * The SPARC port now uses LRA by default.
   2147      * Support for the new Subtract-Extended-with-Carry instruction
   2148        available in SPARC M7 (Niagara 7) has been added.
   2149 
   2150 Operating Systems
   2151 
   2152   AIX
   2153 
   2154      * Visibility support has been enabled for AIX 7.1 and above.
   2155 
   2156   Fuchsia
   2157 
   2158      * Support has been added for the [20]Fuchsia OS.
   2159 
   2160   RTEMS
   2161 
   2162      * The ABI changes on ARM so that no short enums are used by default.
   2163 
   2164 Other significant improvements
   2165 
   2166      * -fverbose-asm previously emitted information on the meanings of
   2167        assembly expressions. This has been extended so that it now also
   2168        prints comments showing the source lines that correspond to the
   2169        assembly, making it easier to read the generated assembly
   2170        (especially with larger functions). For example, given this C
   2171        source file:
   2172 
   2173 int test (int n)
   2174 {
   2175   int i;
   2176   int total = 0;
   2177 
   2178   for (i = 0; i < n; i++)
   2179     total += i * i;
   2180   return total;
   2181 }
   2182 
   2183        -fverbose-asm now gives output similar to this for the function
   2184        body (when compiling for x86_64, with -Os):
   2185 
   2186        .text
   2187        .globl  test
   2188        .type   test, @@function
   2189 test:
   2190 .LFB0:
   2191        .cfi_startproc
   2192 # example.c:4:   int total = 0;
   2193        xorl    %eax, %eax      # <retval>
   2194 # example.c:6:   for (i = 0; i < n; i++)
   2195        xorl    %edx, %edx      # i
   2196 .L2:
   2197 # example.c:6:   for (i = 0; i < n; i++)
   2198        cmpl    %edi, %edx      # n, i
   2199        jge     .L5     #,
   2200 # example.c:7:     total += i * i;
   2201        movl    %edx, %ecx      # i, tmp92
   2202        imull   %edx, %ecx      # i, tmp92
   2203 # example.c:6:   for (i = 0; i < n; i++)
   2204        incl    %edx    # i
   2205 # example.c:7:     total += i * i;
   2206        addl    %ecx, %eax      # tmp92, <retval>
   2207        jmp     .L2     #
   2208 .L5:
   2209 # example.c:10: }
   2210        ret
   2211        .cfi_endproc
   2212 
   2213      * Two new options have been added for printing fix-it hints:
   2214           + -fdiagnostics-parseable-fixits allows for fix-it hints to be
   2215             emitted in a machine-readable form, suitable for consumption
   2216             by IDEs. For example, given:
   2217 
   2218 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did
   2219 you mean 'color'?
   2220    return ptr->colour;
   2221                ^~~~~~
   2222                color
   2223 
   2224             it will emit:
   2225 
   2226 fix-it:"spellcheck-fields.cc":{52:13-52:19}:"color"
   2227 
   2228           + -fdiagnostics-generate-patch will print a patch in "unified"
   2229             format after any diagnostics are printed, showing the result
   2230             of applying all fix-it hints. For the above example it would
   2231             emit:
   2232 
   2233 --- spellcheck-fields.cc
   2234 +++ spellcheck-fields.cc
   2235 @@ -49,5 +49,5 @@
   2236 
   2237  color get_color(struct s *ptr)
   2238  {
   2239 -  return ptr->colour;
   2240 +  return ptr->color;
   2241  }
   2242 
   2243      * The gcc and g++ driver programs will now provide suggestions for
   2244        misspelled arguments to command-line options.
   2245 
   2246 $ gcc -c test.c -ftls-model=global-dinamic
   2247 gcc: error: unknown TLS model 'global-dinamic'
   2248 gcc: note: valid arguments to '-ftls-model=' are: global-dynamic initial-exec lo
   2249 cal-dynamic local-exec; did you mean 'global-dynamic'?
   2250 
   2251      * The compiler will now provide suggestions for misspelled
   2252        parameters.
   2253 
   2254 $ gcc -c test.c --param max-early-inliner-iteration=3
   2255 cc1: error: invalid --param name 'max-early-inliner-iteration'; did you mean 'ma
   2256 x-early-inliner-iterations'?
   2257 
   2258      * Profile-guided optimization (PGO) instrumentation, as well as test
   2259        coverage (GCOV), can newly instrument constructors (functions marks
   2260        with __attribute__((constructor))), destructors and C++
   2261        constructors (and destructors) of classes that are used as the type
   2262        of a global variable.
   2263      * A new option -fprofile-update=atomic prevents creation of corrupted
   2264        profiles created during an instrumentation run (-fprofile=generate)
   2265        of an application. The downside of the option is a speed penalty.
   2266        Providing -pthread on the command line selects atomic profile
   2267        updating (when supported by the target).
   2268      * GCC's already extensive testsuite has gained some new capabilities,
   2269        to further improve the reliability of the compiler:
   2270           + GCC now has an internal unit-testing API and a suite of tests
   2271             for programmatic self-testing of subsystems.
   2272           + GCC's C front end has been extended so that it can parse dumps
   2273             of GCC's internal representations, allowing for DejaGnu tests
   2274             that more directly exercise specific optimization passes. This
   2275             covers both the [21]GIMPLE representation (for testing
   2276             higher-level optimizations) and the [22]RTL representation,
   2277             allowing for more direct testing of lower-level details, such
   2278             as register allocation and instruction selection.
   2279 
   2280 GCC 7.1
   2281 
   2282    This is the [23]list of problem reports (PRs) from GCC's bug tracking
   2283    system that are known to be fixed in the 7.1 release. This list might
   2284    not be complete (that is, it is possible that some PRs that have been
   2285    fixed are not listed here).
   2286 
   2287 GCC 7.2
   2288 
   2289    This is the [24]list of problem reports (PRs) from GCC's bug tracking
   2290    system that are known to be fixed in the 7.2 release. This list might
   2291    not be complete (that is, it is possible that some PRs that have been
   2292    fixed are not listed here).
   2293 
   2294   Target Specific Changes
   2295 
   2296     SPARC
   2297 
   2298      * Support for the SPARC M8 processor has been added.
   2299      * The switches -mfix-ut700 and -mfix-gr712rc have been added to work
   2300        around an erratum in LEON3FT processors.
   2301      * Use of the Floating-point Multiply Single to Double (FsMULd)
   2302        instruction can now be controlled by the -mfsmuld and -fno-fsmuld
   2303        options.
   2304 
   2305   Operating Systems
   2306 
   2307     RTEMS
   2308 
   2309      * The Ada run-time support uses now thread-local storage (TLS).
   2310      * Support for RISC-V has been added.
   2311      * Support for 64-bit PowerPC using the ELFv2 ABI with 64-bit long
   2312        double has been added.
   2313 
   2314 GCC 7.3
   2315 
   2316    This is the [25]list of problem reports (PRs) from GCC's bug tracking
   2317    system that are known to be fixed in the 7.3 release. This list might
   2318    not be complete (that is, it is possible that some PRs that have been
   2319    fixed are not listed here).
   2320 
   2321   Target Specific Changes
   2322 
   2323     SPARC
   2324 
   2325      * Workarounds for the four [26]LEON3FT errata GRLIB-TN-0010..0013
   2326        have been added. Relevant errata are activated by the target
   2327        specific -mfix-ut699, -mfix-ut700 and -mfix-gr712rc switches.
   2328 
   2329   Operating Systems
   2330 
   2331     RTEMS
   2332 
   2333      * Support has been added for Epiphany target.
   2334 
   2335 GCC 7.4
   2336 
   2337    This is the [27]list of problem reports (PRs) from GCC's bug tracking
   2338    system that are known to be fixed in the 7.4 release. This list might
   2339    not be complete (that is, it is possible that some PRs that have been
   2340    fixed are not listed here).
   2341 
   2342 GCC 7.5
   2343 
   2344    This is the [28]list of problem reports (PRs) from GCC's bug tracking
   2345    system that are known to be fixed in the 7.5 release. This list might
   2346    not be complete (that is, it is possible that some PRs that have been
   2347    fixed are not listed here).
   2348 
   2349 
   2350     For questions related to the use of GCC, please consult these web
   2351     pages and the [29]GCC manuals. If that fails, the
   2352     [30]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   2353     web pages and the development of GCC are welcome on our developer
   2354     list at [31]gcc (a] gcc.gnu.org. All of [32]our lists have public
   2355     archives.
   2356 
   2357    Copyright (C) [33]Free Software Foundation, Inc. Verbatim copying and
   2358    distribution of this entire article is permitted in any medium,
   2359    provided this notice is preserved.
   2360 
   2361    These pages are [34]maintained by the GCC team. Last modified
   2362    2019-11-28[35].
   2363 
   2364 References
   2365 
   2366    1. http://gcc.gnu.org/gcc-7/porting_to.html
   2367    2. http://gcc.gnu.org/onlinedocs/index.html#current
   2368    3. https://gcc.gnu.org/wiki/LRAIsDefault
   2369    4. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/manual/profile_mode.html
   2370    5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728
   2371    6. http://www.dwarfstd.org/Download.php
   2372    7. https://gcc.gnu.org/wiki/OpenACC
   2373    8. https://gcc.gnu.org/wiki/Offloading
   2374    9. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Object-Size-Checking.html
   2375   10. https://gcc.gnu.org/projects/cxx-status.html#cxx1z
   2376   11. http://wg21.link/p0136
   2377   12. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/libstdc++/manual/using_dual_abi.html
   2378   13. https://www.openmp.org/specifications/
   2379   14. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/jit/topics/expressions.html#gcc_jit_rvalue_set_bool_require_tail_call
   2380   15. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AArch64-Options.html#AArch64-Options
   2381   16. https://gcc.gnu.org/install/configure.html
   2382   17. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Variable-Attributes.html
   2383   18. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/AVR-Built-in-Functions.html
   2384   19. https://gcc.gnu.org/wiki/Offloading
   2385   20. https://fuchsia.googlesource.com/
   2386   21. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/GIMPLE-Tests.html
   2387   22. https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gccint/RTL-Tests.html
   2388   23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.0
   2389   24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.2
   2390   25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.3
   2391   26. https://www.gaisler.com/index.php/information/app-tech-notes
   2392   27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.4
   2393   28. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=7.5
   2394   29. https://gcc.gnu.org/onlinedocs/
   2395   30. mailto:gcc-help (a] gcc.gnu.org
   2396   31. mailto:gcc (a] gcc.gnu.org
   2397   32. https://gcc.gnu.org/lists.html
   2398   33. https://www.fsf.org/
   2399   34. https://gcc.gnu.org/about.html
   2400   35. http://validator.w3.org/check/referer
   2401 ======================================================================
   2402 http://gcc.gnu.org/gcc-6/index.html
   2403                               GCC 6 Release Series
   2404 
   2405    (This release series is no longer supported.)
   2406 
   2407    October 26, 2018
   2408 
   2409    The [1]GNU project and the GCC developers are pleased to announce the
   2410    release of GCC 6.5.
   2411 
   2412    This release is a bug-fix release, containing fixes for regressions in
   2413    GCC 6.4 relative to previous releases of GCC.
   2414 
   2415 Release History
   2416 
   2417    GCC 6.5
   2418           October 26, 2018 ([2]changes, [3]documentation)
   2419 
   2420    GCC 6.4
   2421           July 4, 2017 ([4]changes, [5]documentation)
   2422 
   2423    GCC 6.3
   2424           December 21, 2016 ([6]changes, [7]documentation)
   2425 
   2426    GCC 6.2
   2427           August 22, 2016 ([8]changes, [9]documentation)
   2428 
   2429    GCC 6.1
   2430           April 27, 2016 ([10]changes, [11]documentation)
   2431 
   2432 References and Acknowledgements
   2433 
   2434    GCC used to stand for the GNU C Compiler, but since the compiler
   2435    supports several other languages aside from C, it now stands for the
   2436    GNU Compiler Collection.
   2437 
   2438    A list of [12]successful builds is updated as new information becomes
   2439    available.
   2440 
   2441    The GCC developers would like to thank the numerous people that have
   2442    contributed new features, improvements, bug fixes, and other changes as
   2443    well as test results to GCC. This [13]amazing group of volunteers is
   2444    what makes GCC successful.
   2445 
   2446    For additional information about GCC please refer to the [14]GCC
   2447    project web site or contact the [15]GCC development mailing list.
   2448 
   2449    To obtain GCC please use [16]our mirror sites or [17]our version
   2450    control system.
   2451 
   2452 
   2453     For questions related to the use of GCC, please consult these web
   2454     pages and the [18]GCC manuals. If that fails, the
   2455     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   2456     web pages and the development of GCC are welcome on our developer
   2457     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   2458     archives.
   2459 
   2460    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   2461    distribution of this entire article is permitted in any medium,
   2462    provided this notice is preserved.
   2463 
   2464    These pages are [23]maintained by the GCC team. Last modified
   2465    2020-01-14[24].
   2466 
   2467 References
   2468 
   2469    1. http://www.gnu.org/
   2470    2. http://gcc.gnu.org/gcc-6/changes.html
   2471    3. http://gcc.gnu.org/onlinedocs/6.5.0/
   2472    4. http://gcc.gnu.org/gcc-6/changes.html
   2473    5. http://gcc.gnu.org/onlinedocs/6.4.0/
   2474    6. http://gcc.gnu.org/gcc-6/changes.html
   2475    7. http://gcc.gnu.org/onlinedocs/6.3.0/
   2476    8. http://gcc.gnu.org/gcc-6/changes.html
   2477    9. http://gcc.gnu.org/onlinedocs/6.2.0/
   2478   10. http://gcc.gnu.org/gcc-6/changes.html
   2479   11. http://gcc.gnu.org/onlinedocs/6.1.0/
   2480   12. http://gcc.gnu.org/gcc-6/buildstat.html
   2481   13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   2482   14. http://gcc.gnu.org/index.html
   2483   15. mailto:gcc (a] gcc.gnu.org
   2484   16. http://gcc.gnu.org/mirrors.html
   2485   17. http://gcc.gnu.org/git.html
   2486   18. https://gcc.gnu.org/onlinedocs/
   2487   19. mailto:gcc-help (a] gcc.gnu.org
   2488   20. mailto:gcc (a] gcc.gnu.org
   2489   21. https://gcc.gnu.org/lists.html
   2490   22. https://www.fsf.org/
   2491   23. https://gcc.gnu.org/about.html
   2492   24. http://validator.w3.org/check/referer
   2493 ======================================================================
   2494 http://gcc.gnu.org/gcc-6/changes.html
   2495                               GCC 6 Release Series
   2496                         Changes, New Features, and Fixes
   2497 
   2498    This page is a brief summary of some of the huge number of improvements
   2499    in GCC 6. For more information, see the [1]Porting to GCC 6 page and
   2500    the [2]full GCC documentation.
   2501 
   2502 Caveats
   2503 
   2504      * The default mode for C++ is now -std=gnu++14 instead of
   2505        -std=gnu++98.
   2506      * Support for a number of older systems and recently unmaintained or
   2507        untested target ports of GCC has been declared obsolete in GCC 6.
   2508        Unless there is activity to revive them, the next release of GCC
   2509        will have their sources permanently removed.
   2510        The following ports for individual systems on particular
   2511        architectures have been obsoleted:
   2512           + SH5 / SH64 (sh64-*-*) as announced [3]here.
   2513      * The AVR port requires binutils version 2.26.1 or later for the fix
   2514        for [4]PR71151 to work.
   2515      * The GCC 6.5 release has an accidental ABI incompatibility for
   2516        nested std::pair objects, for more details see [5]PR 87822. The bug
   2517        causes a layout change for pairs where the first member is also a
   2518        pair, e.g. std::pair<std::pair<X, Y>, Z>. The GCC 6 release series
   2519        is closed so the bug in GCC 6.5 will not be fixed upstream, but
   2520        there is a patch in the bug report to allow it to be fixed by
   2521        anybody packaging GCC 6.5 or installing it themselves.
   2522 
   2523 General Optimizer Improvements
   2524 
   2525      * UndefinedBehaviorSanitizer gained a new sanitization option,
   2526        -fsanitize=bounds-strict, which enables strict checking of array
   2527        bounds. In particular, it enables -fsanitize=bounds as well as
   2528        instrumentation of flexible array member-like arrays.
   2529      * Type-based alias analysis now disambiguates accesses to different
   2530        pointers. This improves precision of the alias oracle by about
   2531        20-30% on higher-level C++ programs. Programs doing invalid type
   2532        punning of pointer types may now need -fno-strict-aliasing to work
   2533        correctly.
   2534      * Alias analysis now correctly supports the weakref and alias
   2535        attributes. This allows accessing both a variable and its alias in
   2536        one translation unit which is common with link-time optimization.
   2537      * Value range propagation now assumes that the this pointer in C++
   2538        member functions is non-null. This eliminates common null pointer
   2539        checks but also breaks some non-conforming code-bases (such as
   2540        Qt-5, Chromium, KDevelop). As a temporary work-around
   2541        -fno-delete-null-pointer-checks can be used. Wrong code can be
   2542        identified by using -fsanitize=undefined.
   2543      * Link-time optimization improvements:
   2544           + warning and error attributes are now correctly preserved by
   2545             declaration linking and thus -D_FORTIFY_SOURCE=2 is now
   2546             supported with -flto.
   2547           + Type merging was fixed to handle C and Fortran
   2548             interoperability rules as defined by the Fortran 2008 language
   2549             standard.
   2550             As an exception, CHARACTER(KIND=C_CHAR) is not inter-operable
   2551             with char in all cases because it is an array while char is
   2552             scalar. INTEGER(KIND=C_SIGNED_CHAR) should be used instead. In
   2553             general, this inter-operability cannot be implemented, for
   2554             example on targets where the argument passing convention for
   2555             arrays differs from scalars.
   2556           + More type information is now preserved at link time, reducing
   2557             the loss of accuracy of the type-based alias analysis compared
   2558             to builds without link-time optimization.
   2559           + Invalid type punning on global variables and declarations is
   2560             now reported with -Wodr-type-mismatch.
   2561           + The size of LTO object files was reduced by about 11%
   2562             (measured by compiling Firefox 46.0).
   2563           + Link-time parallelization (enabled using -flto=n) was
   2564             significantly improved by decreasing the size of streamed data
   2565             when partitioning programs. The size of streamed IL while
   2566             compiling Firefox 46.0 was reduced by 66%.
   2567           + The linker plugin was extended to pass information about the
   2568             type of binary produced to the GCC back end. (That can also be
   2569             controlled manually by -flinker-output.) This makes it
   2570             possible to properly configure the code generator and support
   2571             incremental linking. Incremental linking of LTO objects by gcc
   2572             -r is now supported for plugin-enabled setups.
   2573             There are two ways to perform incremental linking:
   2574               1. Linking by ld -r will result in an object file with all
   2575                  sections from individual object files mechanically
   2576                  merged. This delays the actual link-time optimization to
   2577                  the final linking step and thus permits whole program
   2578                  optimization. Linking the final binary with such object
   2579                  files is however slower.
   2580               2. Linking by gcc -r will lead to link-time optimization and
   2581                  emit the final binary into the object file. Linking such
   2582                  an object file is fast but avoids any benefits from whole
   2583                  program optimization.
   2584             GCC 7 will support incremental link-time optimization with gcc
   2585             -r.
   2586      * Inter-procedural optimization improvements:
   2587           + Basic jump threading is now performed before profile
   2588             construction and inline analysis, resulting in more realistic
   2589             size and time estimates that drive the heuristics of the
   2590             inliner and function cloning passes.
   2591           + Function cloning now more aggressively eliminates unused
   2592             function parameters.
   2593 
   2594 New Languages and Language specific improvements
   2595 
   2596    Compared to GCC 5, the GCC 6 release series includes a much improved
   2597    implementation of the [6]OpenACC 2.0a specification. Highlights are:
   2598      * In addition to single-threaded host-fallback execution, offloading
   2599        is supported for nvptx (Nvidia GPUs) on x86_64 and PowerPC 64-bit
   2600        little-endian GNU/Linux host systems. For nvptx offloading, with
   2601        the OpenACC parallel construct, the execution model allows for an
   2602        arbitrary number of gangs, up to 32 workers, and 32 vectors.
   2603      * Initial support for parallelized execution of OpenACC kernels
   2604        constructs:
   2605           + Parallelization of a kernels region is switched on by
   2606             -fopenacc combined with -O2 or higher.
   2607           + Code is offloaded onto multiple gangs, but executes with just
   2608             one worker, and a vector length of 1.
   2609           + Directives inside a kernels region are not supported.
   2610           + Loops with reductions can be parallelized.
   2611           + Only kernels regions with one loop nest are parallelized.
   2612           + Only the outer-most loop of a loop nest can be parallelized.
   2613           + Loop nests containing sibling loops are not parallelized.
   2614        Typically, using the OpenACC parallel construct gives much better
   2615        performance, compared to the initial support of the OpenACC kernels
   2616        construct.
   2617      * The device_type clause is not supported. The bind and nohost
   2618        clauses are not supported. The host_data directive is not supported
   2619        in Fortran.
   2620      * Nested parallelism (cf. CUDA dynamic parallelism) is not supported.
   2621      * Usage of OpenACC constructs inside multithreaded contexts (such as
   2622        created by OpenMP, or pthread programming) is not supported.
   2623      * If a call to the acc_on_device function has a compile-time constant
   2624        argument, the function call evaluates to a compile-time constant
   2625        value only for C and C++ but not for Fortran.
   2626 
   2627    See the [7]OpenACC and [8]Offloading wiki pages for further
   2628    information.
   2629 
   2630   C family
   2631 
   2632      * Version 4.5 of the [9]OpenMP specification is now supported in the
   2633        C and C++ compilers.
   2634      * The C and C++ compilers now support attributes on enumerators. For
   2635        instance, it is now possible to mark enumerators as deprecated:
   2636 
   2637 enum {
   2638   newval,
   2639   oldval __attribute__ ((deprecated ("too old")))
   2640 };
   2641 
   2642      * Source locations for the C and C++ compilers are now tracked as
   2643        ranges, rather than just points, making it easier to identify the
   2644        subexpression of interest within a complicated expression. For
   2645        example:
   2646 
   2647 test.cc: In function 'int test(int, int, foo, int, int)':
   2648 test.cc:5:16: error: no match for 'operator*' (operand types are 'int' and 'foo'
   2649 )
   2650    return p + q * r * s + t;
   2651               ~~^~~
   2652 
   2653        In addition, there is now initial support for precise diagnostic
   2654        locations within strings:
   2655 
   2656 format-strings.c:3:14: warning: field width specifier '*' expects a matching 'in
   2657 t' argument [-Wformat=]
   2658    printf("%*d");
   2659             ^
   2660 
   2661      * Diagnostics can now contain "fix-it hints", which are displayed in
   2662        context underneath the relevant source code. For example:
   2663 
   2664 fixits.c: In function 'bad_deref':
   2665 fixits.c:11:13: error: 'ptr' is a pointer; did you mean to use '->'?
   2666    return ptr.x;
   2667              ^
   2668              ->
   2669 
   2670      * The C and C++ compilers now offer suggestions for misspelled field
   2671        names:
   2672 
   2673 spellcheck-fields.cc:52:13: error: 'struct s' has no member named 'colour'; did
   2674 you mean 'color'?
   2675    return ptr->colour;
   2676                ^~~~~~
   2677 
   2678      * New command-line options have been added for the C and C++
   2679        compilers:
   2680           + -Wshift-negative-value warns about left shifting a negative
   2681             value.
   2682           + -Wshift-overflow warns about left shift overflows. This
   2683             warning is enabled by default. -Wshift-overflow=2 also warns
   2684             about left-shifting 1 into the sign bit.
   2685           + -Wtautological-compare warns if a self-comparison always
   2686             evaluates to true or false. This warning is enabled by -Wall.
   2687           + -Wnull-dereference warns if the compiler detects paths that
   2688             trigger erroneous or undefined behavior due to dereferencing a
   2689             null pointer. This option is only active when
   2690             -fdelete-null-pointer-checks is active, which is enabled by
   2691             optimizations in most targets. The precision of the warnings
   2692             depends on the optimization options used.
   2693           + -Wduplicated-cond warns about duplicated conditions in an
   2694             if-else-if chain.
   2695           + -Wmisleading-indentation warns about places where the
   2696             indentation of the code gives a misleading idea of the block
   2697             structure of the code to a human reader. For example, given
   2698             [10]CVE-2014-1266:
   2699 
   2700 sslKeyExchange.c: In function 'SSLVerifySignedServerKeyExchange':
   2701 sslKeyExchange.c:629:3: warning: this 'if' clause does not guard... [-Wmisleadin
   2702 g-indentation]
   2703     if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0)
   2704     ^~
   2705 sslKeyExchange.c:631:5: note: ...this statement, but the latter is misleadingly
   2706 indented as if it is guarded by the 'if'
   2707         goto fail;
   2708         ^~~~
   2709 
   2710             This warning is enabled by -Wall.
   2711      * The C and C++ compilers now emit saner error messages if
   2712        merge-conflict markers are present in a source file.
   2713 
   2714 test.c:3:1: error: version control conflict marker in file
   2715  <<<<<<< HEAD
   2716  ^~~~~~~
   2717 
   2718   C
   2719 
   2720      * It is possible to disable warnings when an initialized field of a
   2721        structure or a union with side effects is being overridden when
   2722        using designated initializers via a new warning option
   2723        -Woverride-init-side-effects.
   2724      * A new type attribute scalar_storage_order applying to structures
   2725        and unions has been introduced. It specifies the storage order (aka
   2726        endianness) in memory of scalar fields in structures or unions.
   2727 
   2728   C++
   2729 
   2730      * The default mode has been changed to -std=gnu++14.
   2731      * [11]C++ Concepts are now supported when compiling with -fconcepts.
   2732      * -flifetime-dse is more aggressive in dead-store elimination in
   2733        situations where a memory store to a location precedes a
   2734        constructor to that memory location.
   2735      * G++ now supports [12]C++17 fold expressions, u8 character literals,
   2736        extended static_assert, and nested namespace definitions.
   2737      * G++ now allows constant evaluation for all non-type template
   2738        arguments.
   2739      * G++ now supports C++ Transactional Memory when compiling with
   2740        -fgnu-tm.
   2741 
   2742     Runtime Library (libstdc++)
   2743 
   2744      * Extensions to the C++ Library to support mathematical special
   2745        functions (ISO/IEC 29124:2010), thanks to Edward Smith-Rowland.
   2746      * Experimental support for C++17, including the following new
   2747        features:
   2748           + std::uncaught_exceptions function (this is also available for
   2749             -std=gnu++NN modes);
   2750           + new member functions try_emplace and insert_or_assign for
   2751             unique_key maps;
   2752           + non-member functions std::size, std::empty, and std::data for
   2753             accessing containers and arrays;
   2754           + std::invoke;
   2755           + std::shared_mutex;
   2756           + std::void_t and std::bool_constant metaprogramming utilities.
   2757        Thanks to Ville Voutilainen for contributing many of the C++17
   2758        features.
   2759      * An experimental implementation of the File System TS.
   2760      * Experimental support for most features of the second version of the
   2761        Library Fundamentals TS. This includes polymorphic memory resources
   2762        and array support in shared_ptr, thanks to Fan You.
   2763      * Some assertions checked by Debug Mode can now also be enabled by
   2764        _GLIBCXX_ASSERTIONS. The subset of checks enabled by the new macro
   2765        have less run-time overhead than the full _GLIBCXX_DEBUG checks and
   2766        don't affect the library ABI, so can be enabled per-translation
   2767        unit.
   2768      * Timed mutex types are supported on more targets, including Darwin.
   2769      * Improved std::locale support for DragonFly and FreeBSD, thanks to
   2770        John Marino and Andreas Tobler.
   2771 
   2772   Fortran
   2773 
   2774      * Fortran 2008 SUBMODULE support.
   2775      * Fortran 2015 EVENT_TYPE, EVENT_POST, EVENT_WAIT, and EVENT_QUERY
   2776        support.
   2777      * Improved support for Fortran 2003 deferred-length character
   2778        variables.
   2779      * Improved support for OpenMP and OpenACC.
   2780      * The MATMUL intrinsic is now inlined for straightforward cases if
   2781        front-end optimization is active. The maximum size for inlining can
   2782        be set to n with the -finline-matmul-limit=n option and turned off
   2783        with -finline-matmul-limit=0.
   2784      * The -Wconversion-extra option will warn about REAL constants which
   2785        have excess precision for their kind.
   2786      * The -Winteger-division option has been added, which warns about
   2787        divisions of integer constants which are truncated. This option is
   2788        included in -Wall by default.
   2789 
   2790 libgccjit
   2791 
   2792      * The driver code is now run in-process within libgccjit, providing a
   2793        small speed-up of the compilation process.
   2794      * The API has gained entrypoints for
   2795           + [13]timing how long was spent in different parts of code,
   2796           + [14]creating switch statements,
   2797           + [15]allowing unreachable basic blocks in a function, and
   2798           + [16]adding arbitrary command-line options to a compilation.
   2799 
   2800 New Targets and Target Specific Improvements
   2801 
   2802   AArch64
   2803 
   2804      * A number of AArch64-specific options have been added. The most
   2805        important ones are summarised in this section; for more detailed
   2806        information please refer to the documentation.
   2807      * The command-line options -march=native, -mcpu=native and
   2808        -mtune=native are now available on native AArch64 GNU/Linux
   2809        systems. Specifying these options causes GCC to auto-detect the
   2810        host CPU and choose the optimal setting for that system.
   2811      * -fpic is now supported when generating code for the small code
   2812        model (-mcmodel=small). The size of the global offset table (GOT)
   2813        is limited to 28KiB under the LP64 SysV ABI, and 15KiB under the
   2814        ILP32 SysV ABI.
   2815      * The AArch64 port now supports target attributes and pragmas. Please
   2816        refer to the [17]documentation for details of available attributes
   2817        and pragmas as well as usage instructions.
   2818      * Link-time optimization across translation units with different
   2819        target-specific options is now supported.
   2820      * The option -mtls-size= is now supported. It can be used to specify
   2821        the bit size of TLS offsets, allowing GCC to generate better TLS
   2822        instruction sequences.
   2823      * The option -fno-plt is now fully functional.
   2824      * The ARMv8.1-A architecture and the Large System Extensions are now
   2825        supported. They can be used by specifying the -march=armv8.1-a
   2826        option. Additionally, the +lse option extension can be used in a
   2827        similar fashion to other option extensions. The Large System
   2828        Extensions introduce new instructions that are used in the
   2829        implementation of atomic operations.
   2830      * The ACLE half-precision floating-point type __fp16 is now supported
   2831        in the C and C++ languages.
   2832      * The ARM Cortex-A35 processor is now supported via the
   2833        -mcpu=cortex-a35 and -mtune=cortex-a35 options as well as the
   2834        equivalent target attributes and pragmas.
   2835      * The Qualcomm QDF24xx processor is now supported via the
   2836        -mcpu=qdf24xx and -mtune=qdf24xx options as well as the equivalent
   2837        target attributes and pragmas.
   2838      * Code generation for the ARM Cortex-A57 processor is improved. Among
   2839        general code generation improvements, a better algorithm is added
   2840        for allocating registers to floating-point multiply-accumulate
   2841        instructions offering increased performance when compiling with
   2842        -mcpu=cortex-a57 or -mtune=cortex-a57.
   2843      * Code generation for the ARM Cortex-A53 processor is improved. A
   2844        more accurate instruction scheduling model for the processor is now
   2845        used, and a number of compiler tuning parameters have been set to
   2846        offer increased performance when compiling with -mcpu=cortex-a53 or
   2847        -mtune=cortex-a53.
   2848      * Code generation for the Samsung Exynos M1 processor is improved. A
   2849        more accurate instruction scheduling model for the processor is now
   2850        used, and a number of compiler tuning parameters have been set to
   2851        offer increased performance when compiling with -mcpu=exynos-m1 or
   2852        -mtune=exynos-m1.
   2853      * Improvements in the generation of conditional branches and literal
   2854        pools allow the compiler to compile functions of a large size.
   2855        Constant pools are now placed into separate rodata sections. The
   2856        new option -mpc-relative-literal-loads generates per-function
   2857        literal pools, limiting the maximum size of functions to 1MiB.
   2858      * Several correctness issues generating Advanced SIMD instructions
   2859        for big-endian targets have been fixed resulting in improved code
   2860        generation for ACLE intrinsics with -mbig-endian.
   2861 
   2862   ARM
   2863 
   2864      * Support for revisions of the ARM architecture prior to ARMv4t has
   2865        been deprecated and will be removed in a future GCC release. The
   2866        -mcpu and -mtune values that are deprecated are: arm2, arm250,
   2867        arm3, arm6, arm60, arm600, arm610, arm620, arm7, arm7d, arm7di,
   2868        arm70, arm700, arm700i, arm710, arm720, arm710c, arm7100, arm7500,
   2869        arm7500fe, arm7m, arm7dm, arm7dmi, arm8, arm810, strongarm,
   2870        strongarm110, strongarm1100, strongarm1110, fa526, fa626. The value
   2871        arm7tdmi is still supported. The values of -march that are
   2872        deprecated are: armv2,armv2a,armv3,armv3m,armv4.
   2873      * The ARM port now supports target attributes and pragmas. Please
   2874        refer to the [18]documentation for details of available attributes
   2875        and pragmas as well as usage instructions.
   2876      * Support has been added for the following processors (GCC
   2877        identifiers in parentheses): ARM Cortex-A32 (cortex-a32), ARM
   2878        Cortex-A35 (cortex-a35) and ARM Cortex-R8 (cortex-r8). The GCC
   2879        identifiers can be used as arguments to the -mcpu or -mtune
   2880        options, for example: -mcpu=cortex-a32 or -mtune=cortex-a35.
   2881 
   2882   Heterogeneous Systems Architecture
   2883 
   2884      * GCC can now generate HSAIL (Heterogeneous System Architecture
   2885        Intermediate Language) for simple OpenMP device constructs if
   2886        configured with --enable-offload-targets=hsa. A new libgomp plugin
   2887        then runs the HSA GPU kernels implementing these constructs on HSA
   2888        capable GPUs via a standard HSA run time.
   2889        If the HSA compilation back end determines it cannot output HSAIL
   2890        for a particular input, it gives a warning by default. These
   2891        warnings can be suppressed with -Wno-hsa. To give a few examples,
   2892        the HSA back end does not implement compilation of code using
   2893        function pointers, automatic allocation of variable sized arrays,
   2894        functions with variadic arguments as well as a number of other less
   2895        common programming constructs.
   2896        When compilation for HSA is enabled, the compiler attempts to
   2897        compile composite OpenMP constructs
   2898 
   2899 #pragma omp target teams distribute parallel for
   2900 
   2901        into parallel HSA GPU kernels.
   2902 
   2903   IA-32/x86-64
   2904 
   2905      * GCC now supports the Intel CPU named Skylake with AVX-512
   2906        extensions through -march=skylake-avx512. The switch enables the
   2907        following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW,
   2908        AVX-512DQ.
   2909      * Support for new AMD instructions monitorx and mwaitx has been
   2910        added. This includes new intrinsic and built-in support. It is
   2911        enabled through option -mmwaitx. The instructions monitorx and
   2912        mwaitx implement the same functionality as the old monitor and
   2913        mwait instructions. In addition mwaitx adds a configurable timer.
   2914        The timer value is received as third argument and stored in
   2915        register %ebx.
   2916      * x86-64 targets now allow stack realignment from a word-aligned
   2917        stack pointer using the command-line option -mstackrealign or
   2918        __attribute__ ((force_align_arg_pointer)). This allows functions
   2919        compiled with a vector-aligned stack to be invoked from objects
   2920        that keep only word-alignment.
   2921      * Support for address spaces __seg_fs, __seg_gs, and __seg_tls. These
   2922        can be used to access data via the %fs and %gs segments without
   2923        having to resort to inline assembly. Please refer to the
   2924        [19]documentation for usage instructions.
   2925      * Support for AMD Zen (family 17h) processors is now available
   2926        through the -march=znver1 and -mtune=znver1 options.
   2927 
   2928   MeP
   2929 
   2930      * Support for the MeP (mep-elf) architecture has been deprecated and
   2931        will be removed in a future GCC release.
   2932 
   2933   MSP430
   2934 
   2935      * The MSP430 compiler now has the ability to automatically distribute
   2936        code and data between low memory (addresses below 64K) and high
   2937        memory. This only applies to parts that actually have both memory
   2938        regions and only if the linker script for the part has been
   2939        specifically set up to support this feature.
   2940        A new attribute of either can be applied to both functions and
   2941        data, and this tells the compiler to place the object into low
   2942        memory if there is room and into high memory otherwise. Two other
   2943        new attributes - lower and upper - can be used to explicitly state
   2944        that an object should be placed in the specified memory region. If
   2945        there is not enough left in that region the compilation will fail.
   2946        Two new command-line options - -mcode-region=[lower|upper|either]
   2947        and -mdata-region=[lower|upper|either] - can be used to tell the
   2948        compiler what to do with objects that do not have one of these new
   2949        attributes.
   2950 
   2951   PowerPC / PowerPC64 / RS6000
   2952 
   2953      * PowerPC64 now supports IEEE 128-bit floating-point using the
   2954        __float128 data type. In GCC 6, this is not enabled by default, but
   2955        you can enable it with -mfloat128. The IEEE 128-bit floating-point
   2956        support requires the use of the VSX instruction set. IEEE 128-bit
   2957        floating-point values are passed and returned as a single vector
   2958        value. The software emulator for IEEE 128-bit floating-point
   2959        support is only built on PowerPC GNU/Linux systems where the
   2960        default CPU is at least power7. On future ISA 3.0 systems (POWER 9
   2961        and later), you will be able to use the -mfloat128-hardware option
   2962        to use the ISA 3.0 instructions that support IEEE 128-bit
   2963        floating-point. An additional type (__ibm128) has been added to
   2964        refer to the IBM extended double type that normally implements long
   2965        double. This will allow for a future transition to implementing
   2966        long double with IEEE 128-bit floating-point.
   2967      * Basic support has been added for POWER9 hardware that will use the
   2968        recently published OpenPOWER ISA 3.0 instructions. The following
   2969        new switches are available:
   2970           + -mcpu=power9: Implement all of the ISA 3.0 instructions
   2971             supported by the compiler.
   2972           + -mtune=power9: In the future, apply tuning for POWER9 systems.
   2973             Currently, POWER8 tunings are used.
   2974           + -mmodulo: Generate code using the ISA 3.0 integer instructions
   2975             (modulus, count trailing zeros, array index support, integer
   2976             multiply/add).
   2977           + -mpower9-fusion: Generate code to suitably fuse instruction
   2978             sequences for a POWER9 system.
   2979           + -mpower9-dform: Generate code to use the new D-form
   2980             (register+offset) memory instructions for the vector
   2981             registers.
   2982           + -mpower9-vector: Generate code using the new ISA 3.0 vector
   2983             (VSX or Altivec) instructions.
   2984           + -mpower9-minmax: Reserved for future development.
   2985           + -mtoc-fusion: Keep TOC entries together to provide more fusion
   2986             opportunities.
   2987      * New constraints have been added to support IEEE 128-bit
   2988        floating-point and ISA 3.0 instructions:
   2989           + wb: Altivec register if -mpower9-dform is enabled.
   2990           + we: VSX register if -mpower9-vector is enabled for 64-bit code
   2991             generation.
   2992           + wo: VSX register if -mpower9-vector is enabled.
   2993           + wp: Reserved for future use if long double is implemented with
   2994             IEEE 128-bit floating-point instead of IBM extended double.
   2995           + wq: VSX register if -mfloat128 is enabled.
   2996           + wF: Memory operand suitable for POWER9 fusion load/store.
   2997           + wG: Memory operand suitable for TOC fusion memory references.
   2998           + wL: Integer constant identifying the element number mfvsrld
   2999             accesses within a vector.
   3000      * Support has been added for __builtin_cpu_is() and
   3001        __builtin_cpu_supports(), allowing for very fast access to
   3002        AT_PLATFORM, AT_HWCAP, and AT_HWCAP2 values. This requires use of
   3003        glibc 2.23 or later.
   3004      * All hardware transactional memory builtins now correctly behave as
   3005        memory barriers. Programmers can use #ifdef __TM_FENCE__ to
   3006        determine whether their "old" compiler treats the builtins as
   3007        barriers.
   3008      * Split-stack support has been added for gccgo on PowerPC64 for both
   3009        big- and little-endian (but not for 32-bit). The gold linker from
   3010        at least binutils 2.25.1 must be available in the PATH when
   3011        configuring and building gccgo to enable split stack. (The
   3012        requirement for binutils 2.25.1 applies to PowerPC64 only.) The
   3013        split-stack feature allows a small initial stack size to be
   3014        allocated for each goroutine, which increases as needed.
   3015      * GCC on PowerPC now supports the standard lround function.
   3016      * A new configuration option ---with-advance-toolchain=at was added
   3017        for PowerPC 64-bit GNU/Linux systems to use the header files,
   3018        library files, and the dynamic linker from a specific Advance
   3019        Toolchain release instead of the default versions that are provided
   3020        by the GNU/Linux distribution. In general, this option is intended
   3021        for the developers of GCC, and it is not intended for general use.
   3022      * The "q", "S", "T", and "t" asm-constraints have been removed.
   3023      * The "b", "B", "m", "M", and "W" format modifiers have been removed.
   3024 
   3025   S/390, System z, IBM z Systems
   3026 
   3027      * Support for the IBM z13 processor has been added. When using the
   3028        -march=z13 option, the compiler will generate code making use of
   3029        the new instructions and registers introduced with the vector
   3030        extension facility. The -mtune=z13 option enables z13 specific
   3031        instruction scheduling without making use of new instructions.
   3032        Compiling code with -march=z13 reduces the default alignment of
   3033        vector types bigger than 8 bytes to 8. This is an ABI change and
   3034        care must be taken when linking modules compiled with different
   3035        arch levels which interchange variables containing vector type
   3036        values. For newly compiled code the GNU linker will emit a warning.
   3037      * The -mzvector option enables a C/C++ language extension. This
   3038        extension provides a new keyword vector which can be used to define
   3039        vector type variables. (Note: This is not available when enforcing
   3040        strict standard compliance e.g. with -std=c99. Either enable GNU
   3041        extensions with e.g. -std=gnu99 or use __vector instead of vector.)
   3042        Additionally a set of overloaded builtins is provided which is
   3043        partially compatible to the PowerPC Altivec builtins. In order to
   3044        make use of these builtins the vecintrin.h header file needs to be
   3045        included.
   3046      * The new command-line options -march=native, and -mtune=native are
   3047        now available on native IBM z Systems. Specifying these options
   3048        causes GCC to auto-detect the host CPU and choose the optimal
   3049        setting for that system. If GCC is unable to detect the host CPU
   3050        these options have no effect.
   3051      * The IBM z Systems port now supports target attributes and pragmas.
   3052        Please refer to the [20]documentation for details of available
   3053        attributes and pragmas as well as usage instructions.
   3054      * -fsplit-stack is now supported as part of the IBM z Systems port.
   3055        This feature requires a recent gold linker to be used.
   3056      * Support for the g5 and g6 -march=/-mtune= CPU level switches has
   3057        been deprecated and will be removed in a future GCC release. -m31
   3058        from now on defaults to -march=z900 if not specified otherwise.
   3059        -march=native on a g5/g6 machine will default to -march=z900.
   3060 
   3061   SH
   3062 
   3063      * Support for SH5 / SH64 has been declared obsolete and will be
   3064        removed in future releases.
   3065      * Support for the FDPIC ABI has been added. It can be enabled using
   3066        the new -mfdpic target option and --enable-fdpic configure option.
   3067 
   3068   SPARC
   3069 
   3070      * An ABI bug has been fixed in 64-bit mode. Unfortunately, this
   3071        change will break binary compatibility with earlier releases for
   3072        code it affects, but this should be pretty rare in practice. The
   3073        conditions are: a 16-byte structure containing a double or a 8-byte
   3074        vector in the second half is passed to a subprogram in slot #15,
   3075        for example as 16th parameter if the first 15 ones have at most 8
   3076        bytes. The double or vector was wrongly passed in floating-point
   3077        register %d32 in lieu of on the stack as per the SPARC calling
   3078        conventions.
   3079 
   3080 Operating Systems
   3081 
   3082   AIX
   3083 
   3084      * DWARF debugging support for AIX 7.1 has been enabled as an optional
   3085        debugging format. A more recent Technology Level (TL) and GCC built
   3086        with that level are required for full exploitation of DWARF
   3087        debugging capabilities.
   3088 
   3089   Linux
   3090 
   3091      * Support for the [21]musl C library was added for the AArch64, ARM,
   3092        MicroBlaze, MIPS, MIPS64, PowerPC, PowerPC64, SH, i386, x32 and
   3093        x86_64 targets. It can be selected using the new -mmusl option in
   3094        case musl is not the default libc. GCC defaults to musl libc if it
   3095        is built with a target triplet matching the *-linux-musl* pattern.
   3096 
   3097   RTEMS
   3098 
   3099      * The RTEMS thread model implementation changed. Mutexes now use
   3100        self-contained objects defined in Newlib <sys/lock.h> instead of
   3101        Classic API semaphores. The keys for thread specific data and the
   3102        once function are directly defined via <pthread.h>. Self-contained
   3103        condition variables are provided via Newlib <sys/lock.h>. The RTEMS
   3104        thread model also supports C++11 threads.
   3105      * OpenMP support now uses self-contained objects provided by Newlib
   3106        <sys/lock.h> and offers a significantly better performance compared
   3107        to the POSIX configuration of libgomp. It is possible to configure
   3108        thread pools for each scheduler instance via the environment
   3109        variable GOMP_RTEMS_THREAD_POOLS.
   3110 
   3111   Solaris
   3112 
   3113      * Solaris 12 is now fully supported. Minimal support had already been
   3114        present in GCC 5.3.
   3115      * Solaris 12 provides a full set of startup files (crt1.o, crti.o,
   3116        crtn.o), which GCC now prefers over its own ones.
   3117      * Position independent executables (PIE) are now supported on Solaris
   3118        12.
   3119      * Constructor priority is now supported on Solaris 12 with the system
   3120        linker.
   3121      * libvtv has been ported to Solaris 11 and up.
   3122 
   3123   Windows
   3124 
   3125      * The option -mstackrealign is now automatically activated in 32-bit
   3126        mode whenever the use of SSE instructions is requested.
   3127 
   3128 Other significant improvements
   3129 
   3130      * The gcc and g++ driver programs will now provide suggestions for
   3131        misspelled command-line options.
   3132 
   3133 $ gcc -static-libfortran test.f95
   3134 gcc: error: unrecognized command line option '-static-libfortran'; did you mean
   3135 '-static-libgfortran'?
   3136 
   3137      * The --enable-default-pie configure option enables generation of PIE
   3138        by default.
   3139 
   3140                                     GCC 6.2
   3141 
   3142    This is the [22]list of problem reports (PRs) from GCC's bug tracking
   3143    system that are known to be fixed in the 6.2 release. This list might
   3144    not be complete (that is, it is possible that some PRs that have been
   3145    fixed are not listed here).
   3146 
   3147 Target Specific Changes
   3148 
   3149   SPARC
   3150 
   3151      * Support for --with-cpu-32 and --with-cpu-64 configure options has
   3152        been added on bi-architecture platforms.
   3153      * Support for the SPARC M7 (Niagara 7) processor has been added.
   3154      * Support for the VIS 4.0 instruction set has been added.
   3155 
   3156                                     GCC 6.3
   3157 
   3158    This is the [23]list of problem reports (PRs) from GCC's bug tracking
   3159    system that are known to be fixed in the 6.3 release. This list might
   3160    not be complete (that is, it is possible that some PRs that have been
   3161    fixed are not listed here).
   3162 
   3163 Target Specific Changes
   3164 
   3165   IA-32/x86-64
   3166 
   3167      * Support for the [24]deprecated pcommit instruction has been
   3168        removed.
   3169 
   3170                                     GCC 6.4
   3171 
   3172    This is the [25]list of problem reports (PRs) from GCC's bug tracking
   3173    system that are known to be fixed in the 6.4 release. This list might
   3174    not be complete (that is, it is possible that some PRs that have been
   3175    fixed are not listed here).
   3176 
   3177 Operating Systems
   3178 
   3179   RTEMS
   3180 
   3181      * The ABI changes on ARM so that no short enums are used by default.
   3182 
   3183                                     GCC 6.5
   3184 
   3185    This is the [26]list of problem reports (PRs) from GCC's bug tracking
   3186    system that are known to be fixed in the 6.5 release. This list might
   3187    not be complete (that is, it is possible that some PRs that have been
   3188    fixed are not listed here).
   3189 
   3190 
   3191     For questions related to the use of GCC, please consult these web
   3192     pages and the [27]GCC manuals. If that fails, the
   3193     [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   3194     web pages and the development of GCC are welcome on our developer
   3195     list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public
   3196     archives.
   3197 
   3198    Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and
   3199    distribution of this entire article is permitted in any medium,
   3200    provided this notice is preserved.
   3201 
   3202    These pages are [32]maintained by the GCC team. Last modified
   3203    2019-11-28[33].
   3204 
   3205 References
   3206 
   3207    1. http://gcc.gnu.org/gcc-6/porting_to.html
   3208    2. http://gcc.gnu.org/onlinedocs/index.html#current
   3209    3. https://gcc.gnu.org/ml/gcc/2015-08/msg00101.html
   3210    4. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71151
   3211    5. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87822
   3212    6. https://www.openacc.org/
   3213    7. https://gcc.gnu.org/wiki/OpenACC
   3214    8. https://gcc.gnu.org/wiki/Offloading
   3215    9. https://www.openmp.org/specifications/
   3216   10. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1266
   3217   11. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4377.pdf
   3218   12. https://gcc.gnu.org/projects/cxx-status.html#cxx1z
   3219   13. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/performance.html
   3220   14. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/functions.html#gcc_jit_block_end_with_switch
   3221   15. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_set_bool_allow_unreachable_blocks
   3222   16. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/jit/topics/contexts.html#gcc_jit_context_add_command_line_option
   3223   17. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/AArch64-Function-Attributes.html#AArch64-Function-Attributes
   3224   18. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/ARM-Function-Attributes.html#ARM-Function-Attributes
   3225   19. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/Named-Address-Spaces.html#Named-Address-Spaces
   3226   20. https://gcc.gnu.org/onlinedocs/gcc-6.1.0/gcc/S_002f390-Function-Attributes.html#S_002f390-Function-Attributes
   3227   21. http://www.musl-libc.org/
   3228   22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.2
   3229   23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.3
   3230   24. https://software.intel.com/en-us/blogs/2016/09/12/deprecate-pcommit-instruction
   3231   25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.4
   3232   26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=6.5
   3233   27. https://gcc.gnu.org/onlinedocs/
   3234   28. mailto:gcc-help (a] gcc.gnu.org
   3235   29. mailto:gcc (a] gcc.gnu.org
   3236   30. https://gcc.gnu.org/lists.html
   3237   31. https://www.fsf.org/
   3238   32. https://gcc.gnu.org/about.html
   3239   33. http://validator.w3.org/check/referer
   3240 ======================================================================
   3241 http://gcc.gnu.org/gcc-5/index.html
   3242                               GCC 5 Release Series
   3243 
   3244    (This release series is no longer supported.)
   3245 
   3246    October 10, 2017
   3247 
   3248    The [1]GNU project and the GCC developers are pleased to announce the
   3249    release of GCC 5.5.
   3250 
   3251    This release is a bug-fix release, containing fixes for regressions in
   3252    GCC 5.4 relative to previous releases of GCC.
   3253 
   3254 Release History
   3255 
   3256    GCC 5.5
   3257           October 10, 2017 ([2]changes, [3]documentation)
   3258 
   3259    GCC 5.4
   3260           June 3, 2016 ([4]changes, [5]documentation)
   3261 
   3262    GCC 5.3
   3263           December 4, 2015 ([6]changes, [7]documentation)
   3264 
   3265    GCC 5.2
   3266           July 16, 2015 ([8]changes, [9]documentation)
   3267 
   3268    GCC 5.1
   3269           April 22, 2015 ([10]changes, [11]documentation)
   3270 
   3271 References and Acknowledgements
   3272 
   3273    GCC used to stand for the GNU C Compiler, but since the compiler
   3274    supports several other languages aside from C, it now stands for the
   3275    GNU Compiler Collection.
   3276 
   3277    A list of [12]successful builds is updated as new information becomes
   3278    available.
   3279 
   3280    The GCC developers would like to thank the numerous people that have
   3281    contributed new features, improvements, bug fixes, and other changes as
   3282    well as test results to GCC. This [13]amazing group of volunteers is
   3283    what makes GCC successful.
   3284 
   3285    For additional information about GCC please refer to the [14]GCC
   3286    project web site or contact the [15]GCC development mailing list.
   3287 
   3288    To obtain GCC please use [16]our mirror sites or [17]our version
   3289    control system.
   3290 
   3291 
   3292     For questions related to the use of GCC, please consult these web
   3293     pages and the [18]GCC manuals. If that fails, the
   3294     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   3295     web pages and the development of GCC are welcome on our developer
   3296     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   3297     archives.
   3298 
   3299    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   3300    distribution of this entire article is permitted in any medium,
   3301    provided this notice is preserved.
   3302 
   3303    These pages are [23]maintained by the GCC team. Last modified
   3304    2020-01-14[24].
   3305 
   3306 References
   3307 
   3308    1. http://www.gnu.org/
   3309    2. http://gcc.gnu.org/gcc-5/changes.html
   3310    3. http://gcc.gnu.org/onlinedocs/5.5.0/
   3311    4. http://gcc.gnu.org/gcc-5/changes.html
   3312    5. http://gcc.gnu.org/onlinedocs/5.4.0/
   3313    6. http://gcc.gnu.org/gcc-5/changes.html
   3314    7. http://gcc.gnu.org/onlinedocs/5.3.0/
   3315    8. http://gcc.gnu.org/gcc-5/changes.html
   3316    9. http://gcc.gnu.org/onlinedocs/5.2.0/
   3317   10. http://gcc.gnu.org/gcc-5/changes.html
   3318   11. http://gcc.gnu.org/onlinedocs/5.1.0/
   3319   12. http://gcc.gnu.org/gcc-5/buildstat.html
   3320   13. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   3321   14. http://gcc.gnu.org/index.html
   3322   15. mailto:gcc (a] gcc.gnu.org
   3323   16. http://gcc.gnu.org/mirrors.html
   3324   17. http://gcc.gnu.org/git.html
   3325   18. https://gcc.gnu.org/onlinedocs/
   3326   19. mailto:gcc-help (a] gcc.gnu.org
   3327   20. mailto:gcc (a] gcc.gnu.org
   3328   21. https://gcc.gnu.org/lists.html
   3329   22. https://www.fsf.org/
   3330   23. https://gcc.gnu.org/about.html
   3331   24. http://validator.w3.org/check/referer
   3332 ======================================================================
   3333 http://gcc.gnu.org/gcc-5/changes.html
   3334                               GCC 5 Release Series
   3335                         Changes, New Features, and Fixes
   3336 
   3337 Caveats
   3338 
   3339      * The default mode for C is now -std=gnu11 instead of -std=gnu89.
   3340      * The C++ runtime library (libstdc++) uses a new ABI by default (see
   3341        [1]below).
   3342      * The Graphite framework for loop optimizations no longer requires
   3343        the CLooG library, only ISL version 0.14 (recommended) or 0.12.2.
   3344        The installation manual contains more information about
   3345        requirements to build GCC.
   3346      * The non-standard C++0x type traits has_trivial_default_constructor,
   3347        has_trivial_copy_constructor and has_trivial_copy_assign have been
   3348        deprecated and will be removed in a future version. The standard
   3349        C++11 traits is_trivially_default_constructible,
   3350        is_trivially_copy_constructible and is_trivially_copy_assignable
   3351        should be used instead.
   3352      * On AVR, support has been added for the devices
   3353        ATtiny4/5/9/10/20/40. This requires Binutils 2.25 or newer.
   3354      * The AVR port uses a new scheme to describe supported devices: For
   3355        each supported device the compiler provides a device-specific
   3356        [2]spec file. If the compiler is used together with AVR-LibC, this
   3357        requires at least GCC 5.2 and a version of AVR-LibC which
   3358        implements [3]feature #44574.
   3359 
   3360 General Optimizer Improvements
   3361 
   3362      * Inter-procedural optimization improvements:
   3363           + An Identical Code Folding (ICF) pass (controlled via
   3364             -fipa-icf) has been added. Compared to the identical code
   3365             folding performed by the Gold linker this pass does not
   3366             require function sections. It also performs merging before
   3367             inlining, so inter-procedural optimizations are aware of the
   3368             code re-use. On the other hand not all unifications performed
   3369             by a linker are doable by GCC which must honor aliasing
   3370             information. During link-time optimization of Firefox, this
   3371             pass unifies about 31000 functions, that is 14% overall.
   3372           + The devirtualization pass was significantly improved by adding
   3373             better support for speculative devirtualization and dynamic
   3374             type detection. About 50% of virtual calls in Firefox are now
   3375             speculatively devirtualized during link-time optimization.
   3376           + A new comdat localization pass allows the linker to eliminate
   3377             more dead code in presence of C++ inline functions.
   3378           + Virtual tables are now optimized. Local aliases are used to
   3379             reduce dynamic linking time of C++ virtual tables on ELF
   3380             targets and data alignment has been reduced to limit data
   3381             segment bloat.
   3382           + A new -fno-semantic-interposition option can be used to
   3383             improve code quality of shared libraries where interposition
   3384             of exported symbols is not allowed.
   3385           + Write-only variables are now detected and optimized out.
   3386           + With profile feedback the function inliner can now bypass
   3387             --param inline-insns-auto and --param inline-insns-single
   3388             limits for hot calls.
   3389           + The IPA reference pass was significantly sped up making it
   3390             feasible to enable -fipa-reference with -fprofile-generate.
   3391             This also solves a bottleneck seen when building Chromium with
   3392             link-time optimization.
   3393           + The symbol table and call-graph API was reworked to C++ and
   3394             simplified.
   3395           + The interprocedural propagation of constants now also
   3396             propagates alignments of pointer parameters. This for example
   3397             means that the vectorizer often does not need to generate loop
   3398             prologues and epilogues to make up for potential
   3399             misalignments.
   3400      * Link-time optimization improvements:
   3401           + One Definition Rule based merging of C++ types has been
   3402             implemented. Type merging enables better devirtualization and
   3403             alias analysis. Streaming extra information needed to merge
   3404             types adds about 2-6% of memory size and object size increase.
   3405             This can be controlled by -flto-odr-type-merging.
   3406           + Command-line optimization and target options are now streamed
   3407             on a per-function basis and honored by the link-time
   3408             optimizer. This change makes link-time optimization a more
   3409             transparent replacement of per-file optimizations. It is now
   3410             possible to build projects that require different optimization
   3411             settings for different translation units (such as -ffast-math,
   3412             -mavx, or -finline). Contrary to earlier GCC releases, the
   3413             optimization and target options passed on the link command
   3414             line are ignored.
   3415             Note that this applies only to those command-line options that
   3416             can be passed to optimize and target attributes. Command-line
   3417             options affecting global code generation (such as -fpic),
   3418             warnings (such as -Wodr), optimizations affecting the way
   3419             static variables are optimized (such as -fcommon), debug
   3420             output (such as -g), and --param parameters can be applied
   3421             only to the whole link-time optimization unit. In these cases,
   3422             it is recommended to consistently use the same options at both
   3423             compile time and link time.
   3424           + GCC bootstrap now uses slim LTO object files.
   3425           + Memory usage and link times were improved. Tree merging was
   3426             sped up, memory usage of GIMPLE declarations and types was
   3427             reduced, and, support for on-demand streaming of variable
   3428             constructors was added.
   3429      * Feedback directed optimization improvements:
   3430           + A new auto-FDO mode uses profiles collected by low overhead
   3431             profiling tools (perf) instead of more expensive program
   3432             instrumentation (via -fprofile-generate). SPEC2006 benchmarks
   3433             on x86-64 improve by 4.7% with auto-FDO and by 7.3% with
   3434             traditional feedback directed optimization.
   3435           + Profile precision was improved in presence of C++ inline and
   3436             extern inline functions.
   3437           + The new gcov-tool utility allows manipulating profiles.
   3438           + Profiles are now more tolerant to source file changes (this
   3439             can be controlled by --param profile-func-internal-id).
   3440      * Register allocation improvements:
   3441           + A new local register allocator (LRA) sub-pass, controlled by
   3442             -flra-remat, implements control-flow sensitive global register
   3443             rematerialization. Instead of spilling and restoring a
   3444             register value, it is recalculated if it is profitable. The
   3445             sub-pass improved SPEC2000 generated code by 1% and 0.5%
   3446             correspondingly on ARM and x86-64.
   3447           + Reuse of the PIC hard register, instead of using a fixed
   3448             register, was implemented on x86/x86-64 targets. This improves
   3449             generated PIC code performance as more hard registers can be
   3450             used. Shared libraries can significantly benefit from this
   3451             optimization. Currently it is switched on only for x86/x86-64
   3452             targets. As RA infrastructure is already implemented for PIC
   3453             register reuse, other targets might follow this in the future.
   3454           + A simple form of inter-procedural RA was implemented. When it
   3455             is known that a called function does not use caller-saved
   3456             registers, save/restore code is not generated around the call
   3457             for such registers. This optimization can be controlled by
   3458             -fipa-ra
   3459           + LRA is now much more effective at generating spills of general
   3460             registers into vector registers instead of memory on
   3461             architectures (e.g., modern Intel processors) where this is
   3462             profitable.
   3463      * UndefinedBehaviorSanitizer gained a few new sanitization options:
   3464           + -fsanitize=float-divide-by-zero: detect floating-point
   3465             division by zero;
   3466           + -fsanitize=float-cast-overflow: check that the result of
   3467             floating-point type to integer conversions do not overflow;
   3468           + -fsanitize=bounds: enable instrumentation of array bounds and
   3469             detect out-of-bounds accesses;
   3470           + -fsanitize=alignment: enable alignment checking, detect
   3471             various misaligned objects;
   3472           + -fsanitize=object-size: enable object size checking, detect
   3473             various out-of-bounds accesses.
   3474           + -fsanitize=vptr: enable checking of C++ member function calls,
   3475             member accesses and some conversions between pointers to base
   3476             and derived classes, detect if the referenced object does not
   3477             have the correct dynamic type.
   3478      * Pointer Bounds Checker, a bounds violation detector, has been added
   3479        and can be enabled via -fcheck-pointer-bounds. Memory accesses are
   3480        instrumented with run-time checks of used pointers against their
   3481        bounds to detect pointer bounds violations (overflows). The Pointer
   3482        Bounds Checker is available on x86/x86-64 GNU/Linux targets with a
   3483        new ISA extension Intel MPX support. See the Pointer Bounds Checker
   3484        [4]Wiki page for more details.
   3485 
   3486 New Languages and Language specific improvements
   3487 
   3488      * [5]OpenMP 4.0 specification offloading features are now supported
   3489        by the C, C++, and Fortran compilers. Generic changes:
   3490           + Infrastructure (suitable for any vendor).
   3491           + Testsuite which covers offloading from the [6]OpenMP 4.0
   3492             Examples document.
   3493        Specific for upcoming Intel Xeon Phi products:
   3494           + Run-time library.
   3495           + Card emulator.
   3496      * GCC 5 includes a preliminary implementation of the OpenACC 2.0a
   3497        specification. OpenACC is intended for programming accelerator
   3498        devices such as GPUs. See [7]the OpenACC wiki page for more
   3499        information.
   3500 
   3501   C family
   3502 
   3503      * The default setting of the -fdiagnostics-color= command-line option
   3504        is now [8]configurable when building GCC using configuration option
   3505        --with-diagnostics-color=. The possible values are: never, always,
   3506        auto and auto-if-env. The new default auto uses color only when the
   3507        standard error is a terminal. The default in GCC 4.9 was
   3508        auto-if-env, which is equivalent to auto if there is a non-empty
   3509        GCC_COLORS environment variable, and never otherwise. As in GCC
   3510        4.9, an empty GCC_COLORS variable in the environment will always
   3511        disable colors, no matter what the default is or what command-line
   3512        options are used.
   3513      * A new command-line option -Wswitch-bool has been added for the C
   3514        and C++ compilers, which warns whenever a switch statement has an
   3515        index of boolean type.
   3516      * A new command-line option -Wlogical-not-parentheses has been added
   3517        for the C and C++ compilers, which warns about "logical not" used
   3518        on the left hand side operand of a comparison.
   3519      * A new command-line option -Wsizeof-array-argument has been added
   3520        for the C and C++ compilers, which warns when the sizeof operator
   3521        is applied to a parameter that has been declared as an array in a
   3522        function definition.
   3523      * A new command-line option -Wbool-compare has been added for the C
   3524        and C++ compilers, which warns about boolean expressions compared
   3525        with an integer value different from true/false.
   3526      * Full support for [9]Cilk Plus has been added to the GCC compiler.
   3527        Cilk Plus is an extension to the C and C++ languages to support
   3528        data and task parallelism.
   3529      * A new attribute no_reorder prevents reordering of selected symbols
   3530        against other such symbols or inline assembler. This enables to
   3531        link-time optimize the Linux kernel without having to resort to
   3532        -fno-toplevel-reorder that disables several optimizations.
   3533      * New preprocessor constructs, __has_include and __has_include_next,
   3534        to test the availability of headers have been added.
   3535        This demonstrates a way to include the header <optional> only if it
   3536        is available:
   3537 
   3538 #ifdef __has_include
   3539 #  if __has_include(<optional>)
   3540 #    include <optional>
   3541 #    define have_optional 1
   3542 #  elif __has_include(<experimental/optional>)
   3543 #    include <experimental/optional>
   3544 #    define have_optional 1
   3545 #    define experimental_optional
   3546 #  else
   3547 #    define have_optional 0
   3548 #  endif
   3549 #endif
   3550 
   3551        The header search paths for __has_include and __has_include_next
   3552        are equivalent to those of the standard directive #include and the
   3553        extension #include_next respectively.
   3554      * A new built-in function-like macro to determine the existence of an
   3555        attribute, __has_attribute, has been added. The equivalent built-in
   3556        macro __has_cpp_attribute was added to C++ to support
   3557        [10]Feature-testing recommendations for C++. The macro
   3558        __has_attribute is added to all C-like languages as an extension:
   3559 
   3560 int
   3561 #ifdef __has_attribute
   3562 #  if __has_attribute(__noinline__)
   3563   __attribute__((__noinline__))
   3564 #  endif
   3565 #endif
   3566 foo(int x);
   3567 
   3568        If an attribute exists, a nonzero constant integer is returned. For
   3569        standardized C++ attributes a date is returned, otherwise the
   3570        constant returned is 1. Both __has_attribute and
   3571        __has_cpp_attribute will add underscores to an attribute name if
   3572        necessary to resolve the name. For C++11 and onwards the attribute
   3573        may be scoped.
   3574      * A new set of built-in functions for arithmetics with overflow
   3575        checking has been added: __builtin_add_overflow,
   3576        __builtin_sub_overflow and __builtin_mul_overflow and for
   3577        compatibility with clang also other variants. These builtins have
   3578        two integral arguments (which don't need to have the same type),
   3579        the arguments are extended to infinite precision signed type, +, -
   3580        or * is performed on those, and the result is stored in an integer
   3581        variable pointed to by the last argument. If the stored value is
   3582        equal to the infinite precision result, the built-in functions
   3583        return false, otherwise true. The type of the integer variable that
   3584        will hold the result can be different from the types of the first
   3585        two arguments. The following snippet demonstrates how this can be
   3586        used in computing the size for the calloc function:
   3587 
   3588 void *
   3589 calloc (size_t x, size_t y)
   3590 {
   3591   size_t sz;
   3592   if (__builtin_mul_overflow (x, y, &sz))
   3593     return NULL;
   3594   void *ret = malloc (sz);
   3595   if (ret) memset (res, 0, sz);
   3596   return ret;
   3597 }
   3598 
   3599        On e.g. i?86 or x86-64 the above will result in a mul instruction
   3600        followed by a jump on overflow.
   3601      * The option -fextended-identifiers is now enabled by default for
   3602        C++, and for C99 and later C versions. Various bugs in the
   3603        implementation of extended identifiers have been fixed.
   3604 
   3605   C
   3606 
   3607      * The default mode has been changed to -std=gnu11.
   3608      * A new command-line option -Wc90-c99-compat has been added to warn
   3609        about features not present in ISO C90, but present in ISO C99.
   3610      * A new command-line option -Wc99-c11-compat has been added to warn
   3611        about features not present in ISO C99, but present in ISO C11.
   3612      * It is possible to disable warnings about conversions between
   3613        pointers that have incompatible types via a new warning option
   3614        -Wno-incompatible-pointer-types; warnings about implicit
   3615        incompatible integer to pointer and pointer to integer conversions
   3616        via a new warning option -Wno-int-conversion; and warnings about
   3617        qualifiers on pointers being discarded via a new warning option
   3618        -Wno-discarded-qualifiers.
   3619      * To allow proper use of const qualifiers with multidimensional
   3620        arrays, GCC will not warn about incompatible pointer types anymore
   3621        for conversions between pointers to arrays with and without const
   3622        qualifier (except when using -pedantic). Instead, a new warning is
   3623        emitted only if the const qualifier is lost. This can be controlled
   3624        with a new warning option -Wno-discarded-array-qualifiers.
   3625      * The C front end now generates more precise caret diagnostics.
   3626      * The -pg command-line option now only affects the current file in an
   3627        LTO build.
   3628 
   3629   C++
   3630 
   3631      * G++ now supports [11]C++14 variable templates.
   3632      * -Wnon-virtual-dtor doesn't warn anymore for final classes.
   3633      * Excessive template instantiation depth is now a fatal error. This
   3634        prevents excessive diagnostics that usually do not help to identify
   3635        the problem.
   3636      * G++ and libstdc++ now implement the feature-testing macros from
   3637        [12]Feature-testing recommendations for C++.
   3638      * G++ now allows typename in a template template parameter.
   3639 
   3640 template<template<typename> typename X> struct D; // OK
   3641 
   3642      * G++ now supports [13]C++14 aggregates with non-static data member
   3643        initializers.
   3644 
   3645 struct A { int i, j = i; };
   3646 A a = { 42 }; // a.j is also 42
   3647 
   3648      * G++ now supports [14]C++14 extended constexpr.
   3649 
   3650 constexpr int f (int i)
   3651 {
   3652   int j = 0;
   3653   for (; i > 0; --i)
   3654     ++j;
   3655   return j;
   3656 }
   3657 
   3658 constexpr int i = f(42); // i is 42
   3659 
   3660      * G++ now supports the [15]C++14 sized deallocation functions.
   3661 
   3662 void operator delete (void *, std::size_t) noexcept;
   3663 void operator delete[] (void *, std::size_t) noexcept;
   3664 
   3665      * A new One Definition Rule violation warning (controlled by -Wodr)
   3666        detects mismatches in type definitions and virtual table contents
   3667        during link-time optimization.
   3668      * New warnings -Wsuggest-final-types and -Wsuggest-final-methods help
   3669        developers to annotate programs with final specifiers (or anonymous
   3670        namespaces) to improve code generation. These warnings can be used
   3671        at compile time, but they are more useful in combination with
   3672        link-time optimization.
   3673      * G++ no longer supports [16]N3639 variable length arrays, as they
   3674        were removed from the C++14 working paper prior to ratification.
   3675        GNU VLAs are still supported, so VLA support is now the same in
   3676        C++14 mode as in C++98 and C++11 modes.
   3677      * G++ now allows passing a non-trivially-copyable class via C
   3678        varargs, which is conditionally-supported with
   3679        implementation-defined semantics in the standard. This uses the
   3680        same calling convention as a normal value parameter.
   3681      * G++ now defaults to -fabi-version=9 and -fabi-compat-version=2. So
   3682        various mangling bugs are fixed, but G++ will still emit aliases
   3683        with the old, wrong mangling where feasible. -Wabi=2 will warn
   3684        about differences between ABI version 2 and the current setting.
   3685      * G++ 5.2 fixes the alignment of std::nullptr_t. Most code is likely
   3686        to be unaffected, but -Wabi=8 will warn about a non-static data
   3687        member with type std::nullptr_t which changes position due to this
   3688        change.
   3689 
   3690     Runtime Library (libstdc++)
   3691 
   3692      * A [17]Dual ABI is provided by the library. A new ABI is enabled by
   3693        default. The old ABI is still supported and can be used by defining
   3694        the macro _GLIBCXX_USE_CXX11_ABI to 0 before including any C++
   3695        standard library headers.
   3696      * A new implementation of std::string is enabled by default, using
   3697        the small string optimization instead of copy-on-write reference
   3698        counting.
   3699      * A new implementation of std::list is enabled by default, with an
   3700        O(1) size() function;
   3701      * [18]Full support for C++11, including the following new features:
   3702           + std::deque and std::vector<bool> meet the allocator-aware
   3703             container requirements;
   3704           + movable and swappable iostream classes;
   3705           + support for std::align and std::aligned_union;
   3706           + type traits std::is_trivially_copyable,
   3707             std::is_trivially_constructible, std::is_trivially_assignable
   3708             etc.;
   3709           + I/O manipulators std::put_time, std::get_time, std::hexfloat
   3710             and std::defaultfloat;
   3711           + generic locale-aware std::isblank;
   3712           + locale facets for Unicode conversion;
   3713           + atomic operations for std::shared_ptr;
   3714           + std::notify_all_at_thread_exit() and functions for making
   3715             futures ready at thread exit.
   3716      * Support for the C++11 hexfloat manipulator changes how the num_put
   3717        facet formats floating point types when
   3718        ios_base::fixed|ios_base::scientific is set in a stream's fmtflags.
   3719        This change affects all language modes, even though the C++98
   3720        standard gave no special meaning to that combination of flags. To
   3721        prevent the use of hexadecimal notation for floating point types
   3722        use str.unsetf(std::ios_base::floatfield) to clear the relevant
   3723        bits in str.flags().
   3724      * [19]Full experimental support for C++14, including the following
   3725        new features:
   3726           + std::is_final type trait;
   3727           + heterogeneous comparison lookup in associative containers.
   3728           + global functions cbegin, cend, rbegin, rend, crbegin, and
   3729             crend for range access to containers, arrays and initializer
   3730             lists.
   3731      * [20]Improved experimental support for the Library Fundamentals TS,
   3732        including:
   3733           + class std::experimental::any;
   3734           + function template std::experimental::apply;
   3735           + function template std::experimental::sample;
   3736           + function template std::experimental::search and related
   3737             searcher types;
   3738           + variable templates for type traits;
   3739           + function template std::experimental::not_fn.
   3740      * New random number distributions logistic_distribution and
   3741        uniform_on_sphere_distribution as extensions.
   3742      * [21]GDB Xmethods for containers and std::unique_ptr.
   3743 
   3744   Fortran
   3745 
   3746      * Compatibility notice:
   3747           + The version of the module files (.mod) has been incremented.
   3748           + For free-form source files [22]-Werror=line-truncation is now
   3749             enabled by default. Note that comments exceeding the line
   3750             length are not diagnosed. (For fixed-form source code, the
   3751             same warning is available but turned off by default, such that
   3752             excess characters are ignored. -ffree-line-length-n and
   3753             -ffixed-line-length-n can be used to modify the default line
   3754             lengths of 132 and 72 columns, respectively.)
   3755           + The -Wtabs option is now more sensible: with -Wtabs the
   3756             compiler warns if it encounters tabs and with -Wno-tabs this
   3757             warning is turned off. Before, -Wno-tabs warned and -Wtabs
   3758             disabled the warning. As before, this warning is also enabled
   3759             by -Wall, -pedantic and the f95, f2003, f2008 and f2008ts
   3760             options of -std=.
   3761      * Incomplete support for colorizing diagnostics emitted by gfortran
   3762        has been added. The option [23]-fdiagnostics-color controls when
   3763        color is used in diagnostics. The default value of this option can
   3764        be [24]configured when building GCC. The GCC_COLORS environment
   3765        variable can be used to customize the colors or disable coloring
   3766        completely. Sample diagnostics output:
   3767       $ gfortran -fdiagnostics-color=always -Wuse-without-only test.f90
   3768       test.f90:6:1:
   3769 
   3770        0 continue
   3771        1
   3772       Error: Zero is not a valid statement label at (1)
   3773       test.f90:9:6:
   3774 
   3775          USE foo
   3776             1
   3777       Warning: USE statement at (1) has no ONLY qualifier [-Wuse-without-only]
   3778 
   3779      * The -Wuse-without-only option has been added to warn when a USE
   3780        statement has no ONLY qualifier and thus implicitly imports all
   3781        public entities of the used module.
   3782      * Formatted READ and WRITE statements now work correctly in
   3783        locale-aware programs. For more information and potential caveats,
   3784        see [25]Section 5.3 Thread-safety of the runtime library in the
   3785        manual.
   3786      * [26]Fortran 2003:
   3787           + The intrinsic IEEE modules (IEEE_FEATURES, IEEE_EXCEPTIONS and
   3788             IEEE_ARITHMETIC) are now supported.
   3789      * [27]Fortran 2008:
   3790           + [28]Coarrays: Full experimental support of Fortran 2008's
   3791             coarrays with -fcoarray=lib except for allocatable/pointer
   3792             components of derived-type coarrays. GCC currently only ships
   3793             with a single-image library (libcaf_single), but multi-image
   3794             support based on MPI and GASNet is provided by the libraries
   3795             of the [29]OpenCoarrays project.
   3796      * TS18508 Additional Parallel Features in Fortran:
   3797           + Support for the collective intrinsic subroutines CO_MAX,
   3798             CO_MIN, CO_SUM, CO_BROADCAST and CO_REDUCE has been added,
   3799             including -fcoarray=lib support.
   3800           + Support for the new atomic intrinsics has been added,
   3801             including -fcoarray=lib support.
   3802      * Fortran 2015:
   3803           + Support for IMPLICIT NONE (external, type).
   3804           + ERROR STOP is now permitted in pure procedures.
   3805 
   3806   Go
   3807 
   3808      * GCC 5 provides a complete implementation of the Go 1.4.2 release.
   3809      * Building GCC 5 with Go enabled will install two new programs:
   3810        [30]go and [31]gofmt.
   3811 
   3812 libgccjit
   3813 
   3814    New in GCC 5 is the ability to build GCC as a shared library for
   3815    embedding in other processes (such as interpreters), suitable for
   3816    Just-In-Time compilation to machine code.
   3817 
   3818    The shared library has a [32]C API and a [33]C++ wrapper API providing
   3819    some "syntactic sugar". There are also bindings available from 3rd
   3820    parties for [34]Python and for [35]D.
   3821 
   3822    For example, this library can be used by interpreters for [36]compiling
   3823    functions from bytecode to machine code.
   3824 
   3825    The library can also be used for ahead-of-time compilation, enabling
   3826    GCC to be plugged into a pre-existing front end. An example of using
   3827    this to build a compiler for an esoteric language we'll refer to as
   3828    "brainf" can be seen [37]here.
   3829 
   3830    libgccjit is licensed under the GPLv3 (or at your option, any later
   3831    version)
   3832 
   3833    It should be regarded as experimental at this time.
   3834 
   3835 New Targets and Target Specific Improvements
   3836 
   3837   Reporting stack usage
   3838 
   3839      * The BFIN, FT32, H8300, IQ2000 and M32C targets now support the
   3840        -fstack-usage option.
   3841 
   3842   AArch64
   3843 
   3844      * Code generation for the ARM Cortex-A57 processor has been improved.
   3845        A more accurate instruction scheduling model for the processor is
   3846        now used, and a number of compiler tuning parameters have been set
   3847        to offer increased performance when compiling with -mcpu=cortex-a57
   3848        or -mtune=cortex-a57.
   3849      * A workaround for the ARM Cortex-A53 erratum 835769 has been added
   3850        and can be enabled by giving the -mfix-cortex-a53-835769 option.
   3851        Alternatively it can be enabled by default by configuring GCC with
   3852        the --enable-fix-cortex-a53-835769 option.
   3853      * The optional cryptographic extensions to the ARMv8-A architecture
   3854        are no longer enabled by default when specifying the
   3855        -mcpu=cortex-a53, -mcpu=cortex-a57 or -mcpu=cortex-a57.cortex-a53
   3856        options. To enable these extensions add +crypto to the value of
   3857        -mcpu or -march e.g. -mcpu=cortex-a53+crypto.
   3858      * Support has been added for the following processors (GCC
   3859        identifiers in parentheses): ARM Cortex-A72 (cortex-a72) and
   3860        initial support for its big.LITTLE combination with the ARM
   3861        Cortex-A53 (cortex-a72.cortex-a53), Cavium ThunderX (thunderx),
   3862        Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1).
   3863        The GCC identifiers can be used as arguments to the -mcpu or -mtune
   3864        options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53.
   3865        Using -mcpu=cortex-a72 requires a version of GNU binutils that has
   3866        support for the Cortex-A72.
   3867      * The transitional options -mlra and -mno-lra have been removed. The
   3868        AArch64 backend now uses the local register allocator (LRA) only.
   3869 
   3870   ARM
   3871 
   3872      * Thumb-1 assembly code is now generated in unified syntax. The new
   3873        option -masm-syntax-unified specifies whether inline assembly code
   3874        is using unified syntax. By default the option is off which means
   3875        non-unified syntax is used. However this is subject to change in
   3876        future releases. Eventually the non-unified syntax will be
   3877        deprecated.
   3878      * It is now a configure-time error to use the --with-cpu configure
   3879        option with either of --with-tune or --with-arch.
   3880      * Code generation for the ARM Cortex-A57 processor has been improved.
   3881        A more accurate instruction scheduling model for the processor is
   3882        now used, and a number of compiler tuning parameters have been set
   3883        to offer increased performance when compiling with -mcpu=cortex-a57
   3884        or -mtune=cortex-a57.
   3885      * Support has been added for the following processors (GCC
   3886        identifiers in parentheses): ARM Cortex-A17 (cortex-a17) and
   3887        initial support for its big.LITTLE combination with the ARM
   3888        Cortex-A7 (cortex-a17.cortex-a7), ARM Cortex-A72 (cortex-a72) and
   3889        initial support for its big.LITTLE combination with the ARM
   3890        Cortex-A53 (cortex-a72.cortex-a53), ARM Cortex-M7 (cortex-m7),
   3891        Applied Micro X-Gene 1 (xgene1), and Samsung Exynos M1 (exynos-m1).
   3892        The GCC identifiers can be used as arguments to the -mcpu or -mtune
   3893        options, for example: -mcpu=xgene1 or -mtune=cortex-a72.cortex-a53.
   3894        Using -mcpu=cortex-a72 requires a version of GNU binutils that has
   3895        support for the Cortex-A72.
   3896      * The deprecated option -mwords-little-endian has been removed.
   3897      * The options -mapcs, -mapcs-frame, -mtpcs-frame and
   3898        -mtpcs-leaf-frame which are only applicable to the old ABI have
   3899        been deprecated.
   3900      * The transitional options -mlra and -mno-lra have been removed. The
   3901        ARM backend now uses the local register allocator (LRA) only.
   3902 
   3903   AVR
   3904 
   3905      * The compiler no more supports individual devices like ATmega8.
   3906        Specifying, say, -mmcu=atmega8 triggers the usage of the
   3907        device-specific [38]spec file specs-atmega8 which is part of the
   3908        installation and describes options for the sub-processes like
   3909        compiler proper, assembler and linker. You can add support for a
   3910        new device -mmcu=mydevice as follows:
   3911          1. In an empty directory /someplace, create a new directory
   3912             device-specs.
   3913          2. Copy a device spec file from the installed device-specs
   3914             folder, follow the comments in that file and then save it as
   3915             /someplace/device-specs/specs-mydevice.
   3916          3. Add -B /someplace -mmcu=mydevice to the compiler's
   3917             command-line options. Notice that /someplace must specify an
   3918             absolute path and that mydevice must not start with "avr".
   3919          4. Provided you have a device-specific library libmydevice.a
   3920             available, you can put it at /someplace, dito for a
   3921             device-specific startup file crtmydevice.o.
   3922        The contents of the device spec files depend on the compiler's
   3923        configuration, in particular on --with-avrlibc=no and whether or
   3924        not it is configured for RTEMS.
   3925      * A new command-line option -nodevicelib has been added. It prevents
   3926        the compiler from linking against AVR-LibC's device-specific
   3927        library libdevice.a.
   3928      * The following three command-line options have been added:
   3929 
   3930         -mrmw
   3931                 Set if the device supports the read-modify-write
   3932                 instructions LAC, LAS, LAT and XCH.
   3933 
   3934         -mn-flash=size
   3935                 Specify the flash size of the device in units of 64 KiB,
   3936                 rounded up to the next integer as needed. This option
   3937                 affects the availability of the [39]AVR address-spaces.
   3938 
   3939         -mskip-bug
   3940                 Set if the device is affected by the respective silicon
   3941                 bug.
   3942 
   3943        In general, you don't need to set these options by hand. The new
   3944        device-specific spec file will set them as needed.
   3945 
   3946   IA-32/x86-64
   3947 
   3948      * New [40]ISA extensions support AVX-512{BW,DQ,VL,IFMA,VBMI} of
   3949        Intel's CPU codenamed Skylake Server was added to GCC. That
   3950        includes inline assembly support, new intrinsics, and basic
   3951        autovectorization. These new AVX-512 extensions are available via
   3952        the following GCC switches: AVX-512 Vector Length EVEX feature:
   3953        -mavx512vl, AVX-512 Byte and Word instructions: -mavx512bw, AVX-512
   3954        Dword and Qword instructions: -mavx512dq, AVX-512 FMA-52
   3955        instructions: -mavx512ifma and for AVX-512 Vector Bit Manipulation
   3956        Instructions: -mavx512vbmi.
   3957      * New ISA extensions support Intel MPX was added to GCC. This new
   3958        extension is available via the -mmpx compiler switch. Intel MPX is
   3959        a set of processor features which, with compiler, run-time library
   3960        and OS support, brings increased robustness to software by run-time
   3961        checking pointer references against their bounds. In GCC Intel MPX
   3962        is supported by Pointer Bounds Checker and libmpx run-time
   3963        libraries.
   3964      * The new -mrecord-mcount option for -pg generates a Linux kernel
   3965        style table of pointers to mcount or __fentry__ calls at the
   3966        beginning of functions. The new -mnop-mcount option in addition
   3967        also generates nops in place of the __fentry__ or mcount call, so
   3968        that a call per function can be later patched in. This can be used
   3969        for low overhead tracing or hot code patching.
   3970      * The new -malign-data option controls how GCC aligns variables.
   3971        -malign-data=compat uses increased alignment compatible with GCC
   3972        4.8 and earlier, -malign-data=abi uses alignment as specified by
   3973        the psABI, and -malign-data=cacheline uses increased alignment to
   3974        match the cache line size. -malign-data=compat is the default.
   3975      * The new -mskip-rax-setup option skips setting up the RAX register
   3976        when SSE is disabled and there are no variable arguments passed in
   3977        vector registers. This can be used to optimize the Linux kernel.
   3978 
   3979   MIPS
   3980 
   3981      * MIPS Releases 3 and 5 are now directly supported. Use the
   3982        command-line options -mips32r3, -mips64r3, -mips32r5 and -mips64r5
   3983        to enable code-generation for these processors.
   3984      * The Imagination P5600 processor is now supported using the
   3985        -march=p5600 command-line option.
   3986      * The Cavium Octeon3 processor is now supported using the
   3987        -march=octeon3 command-line option.
   3988      * MIPS Release 6 is now supported using the -mips32r6 and -mips64r6
   3989        command-line options.
   3990      * The o32 ABI has been modified and extended. The o32 64-bit
   3991        floating-point register support is now obsolete and has been
   3992        removed. It has been replaced by three ABI extensions FPXX, FP64A,
   3993        and FP64. The meaning of the -mfp64 command-line option has
   3994        changed. It is now used to enable the FP64A and FP64 ABI
   3995        extensions.
   3996           + The FPXX extension requires that code generated to access
   3997             double-precision values use even-numbered registers. Code that
   3998             adheres to this extension is link-compatible with all other
   3999             o32 double-precision ABI variants and will execute correctly
   4000             in all hardware FPU modes. The command-line options -mabi=32
   4001             -mfpxx can be used to enable this extension. MIPS II is the
   4002             minimum processor required.
   4003           + The o32 FP64A extension requires that floating-point registers
   4004             be 64-bit and odd-numbered single-precision registers are not
   4005             allowed. Code that adheres to the o32 FP64A variant is
   4006             link-compatible with all other o32 double-precision ABI
   4007             variants. The command-line options -mabi=32 -mfp64
   4008             -mno-odd-spreg can be used to enable this extension. MIPS32R2
   4009             is the minimum processor required.
   4010           + The o32 FP64 extension also requires that floating-point
   4011             registers be 64-bit, but permits the use of single-precision
   4012             registers. Code that adheres to the o32 FP64 variant is
   4013             link-compatible with o32 FPXX and o32 FP64A variants only,
   4014             i.e. it is not compatible with the original o32
   4015             double-precision ABI. The command-line options -mabi=32 -mfp64
   4016             -modd-spreg can be used to enable this extension. MIPS32R2 is
   4017             the minimum processor required.
   4018        The new ABI variants can be enabled by default using the configure
   4019        time options --with-fp-32=[32|xx|64] and --with(out)-odd-sp-reg-32.
   4020        It is strongly recommended that all vendors begin to set o32 FPXX
   4021        as the default ABI. This will be required to run the generated code
   4022        on MIPSR5 cores in conjunction with future MIPS SIMD (MSA) code and
   4023        MIPSR6 cores.
   4024      * GCC will now pass all floating-point options to the assembler if
   4025        GNU binutils 2.25 is used. As a result, any inline assembly code
   4026        that uses hard-float instructions should be amended to include a
   4027        .set directive to override the global assembler options when
   4028        compiling for soft-float targets.
   4029 
   4030   NDS32
   4031 
   4032      * The variadic function ABI implementation is now compatible with
   4033        past Andes toolchains where the caller uses registers to pass
   4034        arguments and the callee is in charge of pushing them on stack.
   4035      * The options -mforce-fp-as-gp, -mforbid-fp-as-gp, and -mex9 have
   4036        been removed since they are not yet available in the nds32 port of
   4037        GNU binutils.
   4038      * A new option -mcmodel=[small|medium|large] supports varied code
   4039        models on code generation. The -mgp-direct option became
   4040        meaningless and can be discarded.
   4041 
   4042   RX
   4043 
   4044      * A new command line option -mno-allow-string-insns can be used to
   4045        disable the generation of the SCMPU, SMOVU, SMOVB, SMOVF, SUNTIL,
   4046        SWHILE and RMPA instructions. An erratum released by Renesas shows
   4047        that it is unsafe to use these instructions on addresses within the
   4048        I/O space of the processor. The new option can be used when the
   4049        programmer is concerned that the I/O space might be accessed. The
   4050        default is still to enable these instructions.
   4051 
   4052   SH
   4053 
   4054      * The compiler will now pass the appropriate --isa= option to the
   4055        assembler.
   4056      * The default handling for the GBR has been changed from call
   4057        clobbered to call preserved. The old behavior can be reinstated by
   4058        specifying the option -fcall-used-gbr.
   4059      * Support for the SH4A fpchg instruction has been added which will be
   4060        utilized when switching between single and double precision FPU
   4061        modes.
   4062      * The compiler no longer uses the __fpscr_values array for switching
   4063        between single and double FPU precision modes on non-SH4A targets.
   4064        Instead mode switching will now be performed by storing, modifying
   4065        and reloading the FPSCR, so that other FPSCR bits are preserved
   4066        across mode switches. The __fpscr_values array that is defined in
   4067        libgcc is still present for backwards compatibility, but it will
   4068        not be referenced by compiler generated code anymore.
   4069      * New builtin functions __builtin_sh_get_fpscr and
   4070        __builtin_sh_set_fpscr have been added. The __builtin_sh_set_fpscr
   4071        function will mask the specified bits in such a way that the SZ, PR
   4072        and FR mode bits will be preserved, while changing the other bits.
   4073        These new functions do not reference the __fpscr_values array. The
   4074        old functions __set_fpscr and __get_fpscr in libgcc which access
   4075        the __fpscr_values array are still present for backwards
   4076        compatibility, but their usage is highly discouraged.
   4077      * Some improvements to code generated for __atomic built-in
   4078        functions.
   4079      * When compiling for SH2E the compiler will no longer force the usage
   4080        of delay slots for conditional branch instructions bt and bf. The
   4081        old behavior can be reinstated (e.g. to work around a hardware bug
   4082        in the original SH7055) by specifying the new option
   4083        -mcbranch-force-delay-slot.
   4084 
   4085 Operating Systems
   4086 
   4087   AIX
   4088 
   4089      * GCC now supports stabs debugging continuation lines to allow long
   4090        stabs debug information without overflow that generates AIX linker
   4091        errors.
   4092 
   4093   DragonFly BSD
   4094 
   4095      * GCC now supports the DragonFly BSD operating system.
   4096 
   4097   FreeBSD
   4098 
   4099      * GCC now supports the FreeBSD operating system for the arm port
   4100        through the arm*-*-freebsd* target triplets.
   4101 
   4102   VxWorks MILS
   4103 
   4104      * GCC now supports the MILS (Multiple Independent Levels of Security)
   4105        variant of WindRiver's VxWorks operating system for PowerPC
   4106        targets.
   4107 
   4108 Other significant improvements
   4109 
   4110      * The gcc-ar, gcc-nm, gcc-ranlib wrappers now understand a -B option
   4111        to set the compiler to use.
   4112 
   4113      * When the new command-line option -freport-bug is used, GCC
   4114        automatically generates a developer-friendly reproducer whenever an
   4115        internal compiler error is encountered.
   4116 
   4117                                     GCC 5.2
   4118 
   4119    This is the [41]list of problem reports (PRs) from GCC's bug tracking
   4120    system that are known to be fixed in the 5.2 release. This list might
   4121    not be complete (that is, it is possible that some PRs that have been
   4122    fixed are not listed here).
   4123 
   4124 Target Specific Changes
   4125 
   4126   IA-32/x86-64
   4127 
   4128      * Support for new AMD instructions monitorx and mwaitx has been
   4129        added. This includes new intrinsic and built-in support. It is
   4130        enabled through option -mmwaitx. The instructions monitorx and
   4131        mwaitx implement the same functionality as the old monitor and
   4132        mwait instructions. In addition mwaitx adds a configurable timer.
   4133        The timer value is received as third argument and stored in
   4134        register %ebx.
   4135 
   4136   S/390, System z, IBM z Systems
   4137 
   4138      * Support for the IBM z13 processor has been added. When using the
   4139        -march=z13 option, the compiler will generate code making use of
   4140        the new instructions and registers introduced with the vector
   4141        extension facility. The -mtune=z13 option enables z13 specific
   4142        instruction scheduling without making use of new instructions.
   4143        Compiling code with -march=z13 reduces the default alignment of
   4144        vector types bigger than 8 bytes to 8. This is an ABI change and
   4145        care must be taken when linking modules compiled with different
   4146        arch levels which interchange variables containing vector type
   4147        values. For newly compiled code the GNU linker will emit a warning.
   4148      * The -mzvector option enables a C/C++ language extension. This
   4149        extension provides a new keyword vector which can be used to define
   4150        vector type variables. (Note: This is not available when enforcing
   4151        strict standard compliance e.g. with -std=c99. Either enable GNU
   4152        extensions with e.g. -std=gnu99 or use __vector instead of vector.)
   4153        Additionally a set of overloaded builtins is provided which is
   4154        partially compatible to the PowerPC Altivec builtins. In order to
   4155        make use of these builtins the vecintrin.h header file needs to be
   4156        included.
   4157 
   4158                                     GCC 5.3
   4159 
   4160    This is the [42]list of problem reports (PRs) from GCC's bug tracking
   4161    system that are known to be fixed in the 5.3 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 Target Specific Changes
   4166 
   4167   IA-32/x86-64
   4168 
   4169      * GCC now supports the Intel CPU named Skylake with AVX-512
   4170        extensions through -march=skylake-avx512. The switch enables the
   4171        following ISA extensions: AVX-512F, AVX512VL, AVX-512CD, AVX-512BW,
   4172        AVX-512DQ.
   4173 
   4174   S/390, System z, IBM z Systems
   4175 
   4176      * With this version of GCC IBM z Systems support has been added to
   4177        the GO runtime environment. GCC 5.3 has proven to be able to
   4178        compile larger GO applications on IBM z Systems.
   4179 
   4180                                     GCC 5.4
   4181 
   4182    This is the [43]list of problem reports (PRs) from GCC's bug tracking
   4183    system that are known to be fixed in the 5.4 release. This list might
   4184    not be complete (that is, it is possible that some PRs that have been
   4185    fixed are not listed here).
   4186 
   4187                                     GCC 5.5
   4188 
   4189    This is the [44]list of problem reports (PRs) from GCC's bug tracking
   4190    system that are known to be fixed in the 5.5 release. This list might
   4191    not be complete (that is, it is possible that some PRs that have been
   4192    fixed are not listed here).
   4193 
   4194 Target Specific Changes
   4195 
   4196   IA-32/x86-64
   4197 
   4198      * Support for the [45]deprecated pcommit instruction has been
   4199        removed.
   4200 
   4201 
   4202     For questions related to the use of GCC, please consult these web
   4203     pages and the [46]GCC manuals. If that fails, the
   4204     [47]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   4205     web pages and the development of GCC are welcome on our developer
   4206     list at [48]gcc (a] gcc.gnu.org. All of [49]our lists have public
   4207     archives.
   4208 
   4209    Copyright (C) [50]Free Software Foundation, Inc. Verbatim copying and
   4210    distribution of this entire article is permitted in any medium,
   4211    provided this notice is preserved.
   4212 
   4213    These pages are [51]maintained by the GCC team. Last modified
   4214    2019-11-28[52].
   4215 
   4216 References
   4217 
   4218    1. http://gcc.gnu.org/gcc-5/changes.html#libstdcxx
   4219    2. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html
   4220    3. https://savannah.nongnu.org/bugs/?44574
   4221    4. https://gcc.gnu.org/wiki/Intel MPX support in the GCC compiler
   4222    5. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.pdf
   4223    6. https://www.openmp.org/wp-content/uploads/OpenMP4.0.0.Examples.pdf
   4224    7. https://gcc.gnu.org/wiki/OpenACC
   4225    8. https://gcc.gnu.org/install/configure.html
   4226    9. https://www.cilkplus.org/
   4227   10. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
   4228   11. http://gcc.gnu.org/projects/cxx1y.html
   4229   12. https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
   4230   13. http://gcc.gnu.org/projects/cxx1y.html
   4231   14. http://gcc.gnu.org/projects/cxx1y.html
   4232   15. http://gcc.gnu.org/projects/cxx1y.html
   4233   16. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3639.html
   4234   17. http://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html
   4235   18. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2011
   4236   19. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014
   4237   20. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/libstdc++/manual/manual/status.html#status.iso.2014
   4238   21. https://sourceware.org/gdb/current/onlinedocs/gdb/Xmethods-In-Python.html
   4239   22. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Error-and-Warning-Options.html
   4240   23. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Language-Independent-Options.html
   4241   24. https://gcc.gnu.org/install/configure.html
   4242   25. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gfortran/Thread-safety-of-the-runtime-library.html
   4243   26. https://gcc.gnu.org/wiki/Fortran2003Status
   4244   27. https://gcc.gnu.org/wiki/Fortran2008Status
   4245   28. https://gcc.gnu.org/wiki/Coarray
   4246   29. http://www.opencoarrays.org/
   4247   30. https://golang.org/cmd/go/
   4248   31. https://golang.org/cmd/gofmt/
   4249   32. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/index.html
   4250   33. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/cp/index.html
   4251   34. https://github.com/davidmalcolm/pygccjit
   4252   35. https://github.com/ibuclaw/gccjitd
   4253   36. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial04.html
   4254   37. https://gcc.gnu.org/onlinedocs/gcc-5.1.0/jit/intro/tutorial05.html
   4255   38. https://gcc.gnu.org/onlinedocs/gcc/Spec-Files.html
   4256   39. https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html
   4257   40. https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf
   4258   41. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.2
   4259   42. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.3
   4260   43. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.4
   4261   44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=5.5
   4262   45. https://software.intel.com/en-us/blogs/2016/09/12/deprecate-pcommit-instruction
   4263   46. https://gcc.gnu.org/onlinedocs/
   4264   47. mailto:gcc-help (a] gcc.gnu.org
   4265   48. mailto:gcc (a] gcc.gnu.org
   4266   49. https://gcc.gnu.org/lists.html
   4267   50. https://www.fsf.org/
   4268   51. https://gcc.gnu.org/about.html
   4269   52. http://validator.w3.org/check/referer
   4270 ======================================================================
   4271 http://gcc.gnu.org/gcc-4.9/index.html
   4272                              GCC 4.9 Release Series
   4273 
   4274    (This release series is no longer supported.)
   4275 
   4276    Aug 3, 2016
   4277 
   4278    The [1]GNU project and the GCC developers are pleased to announce the
   4279    release of GCC 4.9.4.
   4280 
   4281    This release is a bug-fix release, containing fixes for regressions in
   4282    GCC 4.9.3 relative to previous releases of GCC.
   4283 
   4284 Release History
   4285 
   4286    GCC 4.9.4
   4287           Aug 3, 2016 ([2]changes, [3]documentation)
   4288 
   4289    GCC 4.9.3
   4290           June 26, 2015 ([4]changes, [5]documentation)
   4291 
   4292    GCC 4.9.2
   4293           October 30, 2014 ([6]changes, [7]documentation)
   4294 
   4295    GCC 4.9.1
   4296           July 16, 2014 ([8]changes, [9]documentation)
   4297 
   4298    GCC 4.9.0
   4299           April 22, 2014 ([10]changes, [11]documentation)
   4300 
   4301 References and Acknowledgements
   4302 
   4303    GCC used to stand for the GNU C Compiler, but since the compiler
   4304    supports several other languages aside from C, it now stands for the
   4305    GNU Compiler Collection.
   4306 
   4307    A list of [12]successful builds is updated as new information becomes
   4308    available.
   4309 
   4310    The GCC developers would like to thank the numerous people that have
   4311    contributed new features, improvements, bug fixes, and other changes as
   4312    well as test results to GCC. This [13]amazing group of volunteers is
   4313    what makes GCC successful.
   4314 
   4315    For additional information about GCC please refer to the [14]GCC
   4316    project web site or contact the [15]GCC development mailing list.
   4317 
   4318    To obtain GCC please use [16]our mirror sites or [17]our version
   4319    control system.
   4320 
   4321 
   4322     For questions related to the use of GCC, please consult these web
   4323     pages and the [18]GCC manuals. If that fails, the
   4324     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   4325     web pages and the development of GCC are welcome on our developer
   4326     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   4327     archives.
   4328 
   4329    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   4330    distribution of this entire article is permitted in any medium,
   4331    provided this notice is preserved.
   4332 
   4333    These pages are [23]maintained by the GCC team. Last modified
   4334    2020-01-14[24].
   4335 
   4336 References
   4337 
   4338    1. http://www.gnu.org/
   4339    2. http://gcc.gnu.org/gcc-4.9/changes.html
   4340    3. http://gcc.gnu.org/onlinedocs/4.9.4/
   4341    4. http://gcc.gnu.org/gcc-4.9/changes.html
   4342    5. http://gcc.gnu.org/onlinedocs/4.9.3/
   4343    6. http://gcc.gnu.org/gcc-4.9/changes.html
   4344    7. http://gcc.gnu.org/onlinedocs/4.9.2/
   4345    8. http://gcc.gnu.org/gcc-4.9/changes.html
   4346    9. http://gcc.gnu.org/onlinedocs/4.9.1/
   4347   10. http://gcc.gnu.org/gcc-4.9/changes.html
   4348   11. https://gcc.gnu.org/onlinedocs/4.9.0/
   4349   12. http://gcc.gnu.org/gcc-4.9/buildstat.html
   4350   13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   4351   14. http://gcc.gnu.org/index.html
   4352   15. mailto:gcc (a] gcc.gnu.org
   4353   16. http://gcc.gnu.org/mirrors.html
   4354   17. http://gcc.gnu.org/git.html
   4355   18. https://gcc.gnu.org/onlinedocs/
   4356   19. mailto:gcc-help (a] gcc.gnu.org
   4357   20. mailto:gcc (a] gcc.gnu.org
   4358   21. https://gcc.gnu.org/lists.html
   4359   22. https://www.fsf.org/
   4360   23. https://gcc.gnu.org/about.html
   4361   24. http://validator.w3.org/check/referer
   4362 ======================================================================
   4363 http://gcc.gnu.org/gcc-4.9/changes.html
   4364                              GCC 4.9 Release Series
   4365                         Changes, New Features, and Fixes
   4366 
   4367 Caveats
   4368 
   4369      * The mudflap run time checker has been removed. The mudflap options
   4370        remain, but do nothing.
   4371      * Support for a number of older systems and recently unmaintained or
   4372        untested target ports of GCC has been declared obsolete in GCC 4.9.
   4373        Unless there is activity to revive them, the next release of GCC
   4374        will have their sources permanently removed.
   4375        The following ports for individual systems on particular
   4376        architectures have been obsoleted:
   4377           + Solaris 9 (*-*-solaris2.9). Details can be found in the
   4378             [1]announcement.
   4379      * On AArch64, the singleton vector types int64x1_t, uint64x1_t and
   4380        float64x1_t exported by arm_neon.h are defined to be the same as
   4381        their base types. This results in incorrect application of
   4382        parameter passing rules to arguments of types int64x1_t and
   4383        uint64x1_t, with respect to the AAPCS64 ABI specification. In
   4384        addition, names of C++ functions with parameters of these types
   4385        (including float64x1_t) are not mangled correctly. The current
   4386        typedef declarations also unintentionally allow implicit casting
   4387        between singleton vector types and their base types. These issues
   4388        will be resolved in a near future release. See [2]PR60825 for more
   4389        information.
   4390 
   4391    More information on porting to GCC 4.9 from previous versions of GCC
   4392    can be found in the [3]porting guide for this release.
   4393 
   4394 General Optimizer Improvements
   4395 
   4396      * AddressSanitizer, a fast memory error detector, is now available on
   4397        ARM.
   4398      * UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior
   4399        detector, has been added and can be enabled via
   4400        -fsanitize=undefined. Various computations will be instrumented to
   4401        detect undefined behavior at runtime. UndefinedBehaviorSanitizer is
   4402        currently available for the C and C++ languages.
   4403      * Link-time optimization (LTO) improvements:
   4404           + Type merging was rewritten. The new implementation is
   4405             significantly faster and uses less memory.
   4406           + Better partitioning algorithm resulting in less streaming
   4407             during link time.
   4408           + Early removal of virtual methods reduces the size of object
   4409             files and improves link-time memory usage and compile time.
   4410           + Function bodies are now loaded on-demand and released early
   4411             improving overall memory usage at link time.
   4412           + C++ hidden keyed methods can now be optimized out.
   4413           + When using a linker plugin, compiling with the -flto option
   4414             now generates slim object files (.o) which only contain
   4415             intermediate language representation for LTO. Use
   4416             -ffat-lto-objects to create files which contain additionally
   4417             the object code. To generate static libraries suitable for LTO
   4418             processing, use gcc-ar and gcc-ranlib; to list symbols from a
   4419             slim object file use gcc-nm. (This requires that ar, ranlib
   4420             and nm have been compiled with plugin support.)
   4421        Memory usage building Firefox with debug enabled was reduced from
   4422        15GB to 3.5GB; link time from 1700 seconds to 350 seconds.
   4423      * Inter-procedural optimization improvements:
   4424           + New type inheritance analysis module improving
   4425             devirtualization. Devirtualization now takes into account
   4426             anonymous name-spaces and the C++11 final keyword.
   4427           + New speculative devirtualization pass (controlled by
   4428             -fdevirtualize-speculatively.
   4429           + Calls that were speculatively made direct are turned back to
   4430             indirect where direct call is not cheaper.
   4431           + Local aliases are introduced for symbols that are known to be
   4432             semantically equivalent across shared libraries improving
   4433             dynamic linking times.
   4434      * Feedback directed optimization improvements:
   4435           + Profiling of programs using C++ inline functions is now more
   4436             reliable.
   4437           + New time profiling determines typical order in which functions
   4438             are executed.
   4439           + A new function reordering pass (controlled by
   4440             -freorder-functions) significantly reduces startup time of
   4441             large applications. Until binutils support is completed, it is
   4442             effective only with link-time optimization.
   4443           + Feedback driven indirect call removal and devirtualization now
   4444             handle cross-module calls when link-time optimization is
   4445             enabled.
   4446 
   4447 New Languages and Language specific improvements
   4448 
   4449      * Version 4.0 of the [4]OpenMP specification is now supported in the
   4450        C and C++ compilers and starting with the 4.9.1 release also in the
   4451        Fortran compiler. The new -fopenmp-simd option can be used to
   4452        enable OpenMP's SIMD directives while ignoring other OpenMP
   4453        directives. The new [5]-fsimd-cost-model= option permits to tune
   4454        the vectorization cost model for loops annotated with OpenMP and
   4455        Cilk Plus simd directives. -Wopenmp-simd warns when the current
   4456        cost model overrides simd directives set by the user.
   4457      * The -Wdate-time option has been added for the C, C++ and Fortran
   4458        compilers, which warns when the __DATE__, __TIME__ or __TIMESTAMP__
   4459        macros are used. Those macros might prevent bit-wise-identical
   4460        reproducible compilations.
   4461 
   4462   Ada
   4463 
   4464      * GNAT switched to Ada 2012 instead of Ada 2005 by default.
   4465 
   4466   C family
   4467 
   4468      * Support for colorizing diagnostics emitted by GCC has been added.
   4469        The [6]-fdiagnostics-color=auto will enable it when outputting to
   4470        terminals, -fdiagnostics-color=always unconditionally. The
   4471        GCC_COLORS environment variable can be used to customize the colors
   4472        or disable coloring. If GCC_COLORS variable is present in the
   4473        environment, the default is -fdiagnostics-color=auto, otherwise
   4474        -fdiagnostics-color=never.
   4475        Sample diagnostics output:
   4476     $ g++ -fdiagnostics-color=always -S -Wall test.C
   4477     test.C: In function int foo():
   4478     test.C:1:14: warning: no return statement in function returning non-void [-W
   4479 return-type]
   4480      int foo () { }
   4481                   ^
   4482     test.C:2:46: error: template instantiation depth exceeds maximum of 900 (use
   4483  -ftemplate-depth= to increase the maximum) instantiating struct X<100>
   4484      template <int N> struct X { static const int value = X<N-1>::value; }; temp
   4485 late struct X<1000>;
   4486                                                   ^
   4487     test.C:2:46:   recursively required from const int X<999>::value
   4488     test.C:2:46:   required from const int X<1000>::value
   4489     test.C:2:88:   required from here
   4490 
   4491     test.C:2:46: error: incomplete type X<100> used in nested name specifier
   4492 
   4493      * With the new [7]#pragma GCC ivdep, the user can assert that there
   4494        are no loop-carried dependencies which would prevent concurrent
   4495        execution of consecutive iterations using SIMD (single instruction
   4496        multiple data) instructions.
   4497      * Support for [8]Cilk Plus has been added and can be enabled with the
   4498        -fcilkplus option. Cilk Plus is an extension to the C and C++
   4499        languages to support data and task parallelism. The present
   4500        implementation follows ABI version 1.2; all features but _Cilk_for
   4501        have been implemented.
   4502 
   4503   C
   4504 
   4505      * ISO C11 atomics (the _Atomic type specifier and qualifier and the
   4506        <stdatomic.h> header) are now supported.
   4507      * ISO C11 generic selections (_Generic keyword) are now supported.
   4508      * ISO C11 thread-local storage (_Thread_local, similar to GNU C
   4509        __thread) is now supported.
   4510      * ISO C11 support is now at a similar level of completeness to ISO
   4511        C99 support: substantially complete modulo bugs, extended
   4512        identifiers (supported except for corner cases when
   4513        -fextended-identifiers is used), floating-point issues (mainly but
   4514        not entirely relating to optional C99 features from Annexes F and
   4515        G) and the optional Annexes K (Bounds-checking interfaces) and L
   4516        (Analyzability).
   4517      * A new C extension __auto_type provides a subset of the
   4518        functionality of C++11 auto in GNU C.
   4519 
   4520   C++
   4521 
   4522      * The G++ implementation of [9]C++1y return type deduction for normal
   4523        functions has been updated to conform to [10]N3638, the proposal
   4524        accepted into the working paper. Most notably, it adds
   4525        decltype(auto) for getting decltype semantics rather than the
   4526        template argument deduction semantics of plain auto:
   4527 
   4528 int& f();
   4529          auto  i1 = f(); // int
   4530 decltype(auto) i2 = f(); // int&
   4531 
   4532      * G++ supports [11]C++1y lambda capture initializers:
   4533 
   4534 [x = 42]{ ... };
   4535 
   4536        Actually, they have been accepted since GCC 4.5, but now the
   4537        compiler doesn't warn about them with -std=c++1y, and supports
   4538        parenthesized and brace-enclosed initializers as well.
   4539      * G++ supports [12]C++1y variable length arrays. G++ has supported
   4540        GNU/C99-style VLAs for a long time, but now additionally supports
   4541        initializers and lambda capture by reference. In C++1y mode G++
   4542        will complain about VLA uses that are not permitted by the draft
   4543        standard, such as forming a pointer to VLA type or applying sizeof
   4544        to a VLA variable. Note that it now appears that VLAs will not be
   4545        part of C++14, but will be part of a separate document and then
   4546        perhaps C++17.
   4547 
   4548 void f(int n) {
   4549   int a[n] = { 1, 2, 3 }; // throws std::bad_array_length if n < 3
   4550   [&a]{ for (int i : a) { cout << i << endl; } }();
   4551   &a; // error, taking address of VLA
   4552 }
   4553 
   4554      * G++ supports the [13]C++1y [[deprecated]] attribute modulo bugs in
   4555        the underlying [[gnu::deprecated]] attribute. Classes and functions
   4556        can be marked deprecated and a diagnostic message added:
   4557 
   4558 class A;
   4559 int bar(int n);
   4560 #if __cplusplus > 201103
   4561 class [[deprecated("A is deprecated in C++14; Use B instead")]] A;
   4562 [[deprecated("bar is unsafe; use foo() instead")]]
   4563 int bar(int n);
   4564 
   4565 int foo(int n);
   4566 class B;
   4567 #endif
   4568 A aa; // warning: 'A' is deprecated : A is deprecated in C++14; Use B instead
   4569 int j = bar(2); // warning: 'int bar(int)' is deprecated : bar is unsafe; use fo
   4570 o() instead
   4571 
   4572      * G++ supports [14]C++1y digit separators. Long numeric literals can
   4573        be subdivided with a single quote ' to enhance readability:
   4574 
   4575 int i = 1048576;
   4576 int j = 1'048'576;
   4577 int k = 0x10'0000;
   4578 int m = 0'004'000'000;
   4579 int n = 0b0001'0000'0000'0000'0000'0000;
   4580 
   4581 double x = 1.602'176'565e-19;
   4582 double y = 1.602'176'565e-1'9;
   4583 
   4584      * G++ supports [15]C++1y generic (polymorphic) lambdas.
   4585 
   4586 // a functional object that will increment any type
   4587 auto incr = [](auto x) { return x++; };
   4588 
   4589      * As a GNU extension, G++ supports explicit template parameter syntax
   4590        for generic lambdas. This can be combined in the expected way with
   4591        the standard auto syntax.
   4592 
   4593 // a functional object that will add two like-type objects
   4594 auto add = [] <typename T> (T a, T b) { return a + b; };
   4595 
   4596      * G++ supports unconstrained generic functions as specified by 4.1.2
   4597        and 5.1.1 of [16]N3889: Concepts Lite Specification. Briefly, auto
   4598        may be used as a type-specifier in a parameter declaration of any
   4599        function declarator in order to introduce an implicit function
   4600        template parameter, akin to generic lambdas.
   4601 
   4602 // the following two function declarations are equivalent
   4603 auto incr(auto x) { return x++; }
   4604 template <typename T>
   4605 auto incr(T x) { return x++; }
   4606 
   4607     Runtime Library (libstdc++)
   4608 
   4609      * [17]Improved support for C++11, including:
   4610           + support for <regex>;
   4611           + The associative containers in <map> and <set> and the
   4612             unordered associative containers in <unordered_map> and
   4613             <unordered_set> meet the allocator-aware container
   4614             requirements;
   4615      * [18]Improved experimental support for the upcoming ISO C++
   4616        standard, C++14, including:
   4617           + fixing constexpr member functions without const;
   4618           + implementation of the std::exchange() utility function;
   4619           + addressing tuples by type;
   4620           + implemention of std::make_unique;
   4621           + implemention of std::shared_lock;
   4622           + making std::result_of SFINAE-friendly;
   4623           + adding operator() to std::integral_constant;
   4624           + adding user-defined literals for standard library types
   4625             std::basic_string, std::chrono::duration, and std::complex;
   4626           + adding two range overloads to non-modifying sequence oprations
   4627             std::equal and std::mismatch;
   4628           + adding IO manipulators for quoted strings;
   4629           + adding constexpr members to <utility>, <complex>, <chrono>,
   4630             and some containers;
   4631           + adding compile-time std::integer_sequence;
   4632           + adding cleaner transformation traits;
   4633           + making <functional>s operator functors easier to use and more
   4634             generic;
   4635      * An implementation of std::experimental::optional.
   4636      * An implementation of std::experimental::string_view.
   4637      * The non-standard function std::copy_exception has been deprecated
   4638        and will be removed in a future version. std::make_exception_ptr
   4639        should be used instead.
   4640 
   4641   Fortran
   4642 
   4643      * Compatibility notice:
   4644           + Module files: The version of the module files (.mod) has been
   4645             incremented; additionally, module files are now compressed.
   4646             Fortran MODULEs compiled by earlier GCC versions have to be
   4647             recompiled, when they are USEd by files compiled with GCC 4.9.
   4648             GCC 4.9 is not able to read .mod files of earlier GCC
   4649             versions; attempting to do so gives an error message. Note:
   4650             The ABI of the produced assembler data itself has not changed:
   4651             object files and libraries are fully compatible with older
   4652             versions (except as stated below).
   4653           + ABI changes:
   4654                o The [19]argument passing ABI has changed for scalar dummy
   4655                  arguments of type INTEGER, REAL, COMPLEX and LOGICAL,
   4656                  which have both the VALUE and the OPTIONAL attributes.
   4657                o To support finalization the virtual table associated with
   4658                  polymorphic variables has changed. Code containing CLASS
   4659                  should be recompiled, including all files which define
   4660                  derived types involved in the type definition used by
   4661                  polymorphic variables. (Note: Due to the incremented
   4662                  module version, trying to mix old code with new code will
   4663                  usually give an error message.)
   4664           + GNU Fortran no longer deallocates allocatable variables or
   4665             allocatable components of variables declared in the main
   4666             program. Since Fortran 2008, the standard explicitly states
   4667             that variables declared in the Fortran main program
   4668             automatically have the SAVE attribute.
   4669           + When opening files, the close-on-exec flag is set if the
   4670             system supports such a feature. This is generally considered
   4671             good practice these days, but if there is a need to pass file
   4672             descriptors to child processes the parent process must now
   4673             remember to clear the close-on-exec flag by calling fcntl(),
   4674             e.g. via ISO_C_BINDING, before executing the child process.
   4675      * The deprecated command-line option -fno-whole-file has been
   4676        removed. (-fwhole-file is the default since GCC 4.6.)
   4677        -fwhole-file/-fno-whole-file continue to be accepted but do not
   4678        influence the code generation.
   4679      * The compiler no longer unconditionally warns about DO loops with
   4680        zero iterations. This warning is now controlled by the -Wzerotrip
   4681        option, which is implied by -Wall.
   4682      * The new NO_ARG_CHECK attribute of the [20]!GCC$ directive can be
   4683        used to disable the type-kind-rank (TKR) argument check for a dummy
   4684        argument. The feature is similar to ISO/IEC TS 29133:2012's
   4685        TYPE(*), except that it additionally also disables the rank check.
   4686        Variables with NO_ARG_CHECK have to be dummy arguments and may only
   4687        be used as argument to ISO_C_BINDING's C_LOC and as actual argument
   4688        to another NO_ARG_CHECK dummy argument; also the other constraints
   4689        of TYPE(*) apply. The dummy arguments should be declared as scalar
   4690        or assumed-size variable of type type(*) (recommended)  or of type
   4691        integer, real, complex or logical. With NO_ARG_CHECK, a pointer to
   4692        the data without further type or shape information is passed,
   4693        similar to C's void*. Note that also TS 29113's
   4694        type(*),dimension(..) accepts arguments of any type and rank;
   4695        contrary to NO_ARG_CHECK assumed-rank arguments pass an array
   4696        descriptor which contains the array shape and stride of the
   4697        argument.
   4698      * [21]Fortran 2003:
   4699           + Finalization is now supported. It is currently only done for a
   4700             subset of those situations in which it should occur.
   4701           + Experimental support for scalar character components with
   4702             deferred length (i.e. allocatable string length) in derived
   4703             types has been added. (Deferred-length character variables are
   4704             supported since GCC 4.6.)
   4705      * [22]Fortran 2008:
   4706           + When STOP or ERROR STOP are used to terminate the execution
   4707             and any exception (but inexact) is signaling, a warning is
   4708             printed to ERROR_UNIT, indicating which exceptions are
   4709             signaling. The [23]-ffpe-summary= command-line option can be
   4710             used to fine-tune for which exceptions the warning should be
   4711             shown.
   4712           + Rounding on input (READ) is now handled on systems where
   4713             strtod honours the rounding mode. (For output, rounding is
   4714             supported since GCC 4.5.) Note that for input, the compatible
   4715             rounding mode is handled as nearest (i.e., rounding to an even
   4716             least significant [cf. IEC 60559:1989] for a tie, while
   4717             compatible rounds away from zero in that case).
   4718 
   4719   Go
   4720 
   4721      * GCC 4.9 provides a complete implementation of the Go 1.2.1 release.
   4722 
   4723 New Targets and Target Specific Improvements
   4724 
   4725   AArch64
   4726 
   4727      * The ARMv8-A crypto and CRC instructions are now supported through
   4728        intrinsics. These are enabled when the architecture supports these
   4729        and are available through the -march=armv8-a+crc and
   4730        -march=armv8-a+crypto options.
   4731      * Initial support for ILP32 has now been added to the compiler. This
   4732        is now available through the command-line option -mabi=ilp32.
   4733        Support for ILP32 is considered experimental as the ABI
   4734        specification is still beta.
   4735      * Coverage of more of the ISA including the SIMD extensions has been
   4736        added. The Advanced SIMD intrinsics have also been improved.
   4737      * The new local register allocator (LRA) is now on by default for the
   4738        AArch64 backend.
   4739      * The REE (Redundant extension elimination) pass has now been enabled
   4740        by default for the AArch64 backend.
   4741      * Tuning for the Cortex-A53 and Cortex-A57 has been improved.
   4742      * Initial big.LITTLE tuning support for the combination of Cortex-A57
   4743        and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53
   4744        option.
   4745      * A number of structural changes have been made to both the ARM and
   4746        AArch64 backends to facilitate improved code-generation.
   4747      * As of GCC 4.9.2 a workaround for the ARM Cortex-A53 erratum 835769
   4748        has been added and can be enabled by giving the
   4749        -mfix-cortex-a53-835769 option. Alternatively it can be enabled by
   4750        default by configuring GCC with the --enable-fix-cortex-a53-835769
   4751        option.
   4752 
   4753   ARC
   4754 
   4755      * A port for Synopsys Designware ARC has been contributed by Embecosm
   4756        and Synopsys Inc.
   4757 
   4758   ARM
   4759 
   4760      * Use of Advanced SIMD (Neon) for 64-bit scalar computations has been
   4761        disabled by default. This was found to generate better code in only
   4762        a small number of cases. It can be turned back on with the
   4763        -mneon-for-64bits option.
   4764      * Further support for the ARMv8-A architecture, notably implementing
   4765        the restriction around IT blocks in the Thumb32 instruction set has
   4766        been added. The -mrestrict-it option can be used with
   4767        -march=armv7-a or the -march=armv7ve options to make code
   4768        generation fully compatible with the deprecated instructions in
   4769        ARMv8-A.
   4770      * Support has now been added for the ARMv7ve variant of the
   4771        architecture. This can be used by the -march=armv7ve option.
   4772      * The ARMv8-A crypto and CRC instructions are now supported through
   4773        intrinsics and are available through the -march=armv8-a+crc and
   4774        mfpu=crypto-neon-fp-armv8 options.
   4775      * LRA is now on by default for the ARM target. This can be turned off
   4776        using the -mno-lra option. This option is a purely transitionary
   4777        command-line option and will be removed in a future release. We are
   4778        interested in any bug reports regarding functional and performance
   4779        regressions with LRA.
   4780      * A new option -mslow-flash-data to improve performance of programs
   4781        fetching data on slow flash memory has now been introduced for the
   4782        ARMv7-M profile cores.
   4783      * A new option -mpic-data-is-text-relative for targets that allows
   4784        data segments to be relative to text segments has been added. This
   4785        is on by default for all targets except VxWorks RTP.
   4786      * A number of infrastructural changes have been made to both the ARM
   4787        and AArch64 backends to facilitate improved code-generation.
   4788      * GCC now supports Cortex-A12 and the Cortex-R7 through the
   4789        -mcpu=cortex-a12 and -mcpu=cortex-r7 options.
   4790      * GCC now has tuning for the Cortex-A57 and Cortex-A53 through the
   4791        -mcpu=cortex-a57 and -mcpu=cortex-a53 options.
   4792      * Initial big.LITTLE tuning support for the combination of Cortex-A57
   4793        and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53
   4794        option. Similar support was added for the combination of Cortex-A15
   4795        and Cortex-A7 through the -mcpu=cortex-a15.cortex-a7 option.
   4796      * Further performance optimizations for the Cortex-A15 and the
   4797        Cortex-M4 have been added.
   4798      * A number of code generation improvements for Thumb2 to reduce code
   4799        size when compiling for the M-profile processors.
   4800 
   4801   AVR
   4802 
   4803      * A new command-line option -mfract-convert-truncate has been added.
   4804        It allows compiler to use truncation instead of rounding towards
   4805        zero for fractional fixed-point types.
   4806 
   4807   IA-32/x86-64
   4808 
   4809      * -mfpmath=sse is now implied by -ffast-math on all targets where
   4810        SSE2 is supported.
   4811      * Intel AVX-512 support was added to GCC. That includes inline
   4812        assembly support, new registers and extending existing ones, new
   4813        intrinsics (covered by corresponding testsuite), and basic
   4814        autovectorization. AVX-512 instructions are available via the
   4815        following GCC switches: AVX-512 foundation instructions: -mavx512f,
   4816        AVX-512 prefetch instructions: -mavx512pf, AVX-512 exponential and
   4817        reciprocal instructions: -mavx512er, AVX-512 conflict detection
   4818        instructions: -mavx512cd.
   4819      * It is now possible to call x86 intrinsics from select functions in
   4820        a file that are tagged with the corresponding target attribute
   4821        without having to compile the entire file with the -mxxx option.
   4822        This improves the usability of x86 intrinsics and is particularly
   4823        useful when doing [24]Function Multiversioning.
   4824      * GCC now supports the new Intel microarchitecture named Silvermont
   4825        through -march=silvermont.
   4826      * GCC now supports the new Intel microarchitecture named Broadwell
   4827        through -march=broadwell.
   4828      * Optimizing for other Intel microarchitectures have been renamed to
   4829        -march=nehalem, westmere, sandybridge, ivybridge, haswell, bonnell.
   4830      * -march=generic has been retuned for better support of Intel core
   4831        and AMD Bulldozer architectures. Performance of AMD K7, K8, Intel
   4832        Pentium-M, and Pentium4 based CPUs is no longer considered
   4833        important for generic.
   4834      * -mtune=intel can now be used to generate code running well on the
   4835        most current Intel processors, which are Haswell and Silvermont for
   4836        GCC 4.9.
   4837      * Support to encode 32-bit assembly instructions in 16-bit format is
   4838        now available through the -m16 command-line option.
   4839      * Better inlining of memcpy and memset that is aware of value ranges
   4840        and produces shorter alignment prologues.
   4841      * -mno-accumulate-outgoing-args is now honored when unwind
   4842        information is output. Argument accumulation is also now turned off
   4843        for portions of programs optimized for size.
   4844      * Support for new AMD family 15h processors (Excavator core) is now
   4845        available through the -march=bdver4 and -mtune=bdver4 options.
   4846 
   4847   MSP430
   4848 
   4849      * A new command-line option -mcpu= has been added to the MSP430
   4850        backend. This option is used to specify the ISA to be used.
   4851        Accepted values are msp430 (the default), msp430x and msp430xv2.
   4852        The ISA is no longer deduced from the -mmcu= option as there are
   4853        far too many different MCU names. The -mmcu= option is still
   4854        supported, and this is still used to select linker scripts and
   4855        generate a C preprocessor symbol that will be recognised by the
   4856        msp430.h header file.
   4857 
   4858   NDS32
   4859 
   4860      * A new nds32 port supports the 32-bit architecture from Andes
   4861        Technology Corporation.
   4862      * The port provides initial support for the V2, V3, V3m instruction
   4863        set architectures.
   4864 
   4865   Nios II
   4866 
   4867      * A port for the Altera Nios II has been contributed by Mentor
   4868        Graphics.
   4869 
   4870   PowerPC / PowerPC64 / RS6000
   4871 
   4872      * GCC now supports Power ISA 2.07, which includes support for
   4873        Hardware Transactional Memory (HTM), Quadword atomics and several
   4874        VMX and VSX additions, including Crypto, 64-bit integer, 128-bit
   4875        integer and decimal integer operations.
   4876      * Support for the POWER8 processor is now available through the
   4877        -mcpu=power8 and -mtune=power8 options.
   4878      * The libitm library has been modified to add a HTM fastpath that
   4879        automatically uses POWER's HTM hardware instructions when it is
   4880        executing on a HTM enabled processor.
   4881      * Support for the new powerpc64le-linux platform has been added. It
   4882        defaults to generating code that conforms to the ELFV2 ABI.
   4883 
   4884   S/390, System z
   4885 
   4886      * Support for the Transactional Execution Facility included with the
   4887        IBM zEnterprise zEC12 processor has been added. A set of GCC style
   4888        builtins as well as XLC style builtins are provided. The builtins
   4889        are enabled by default when using the -march=zEC12 option but can
   4890        explicitly be disabled with -mno-htm. Using the GCC builtins also
   4891        libitm supports hardware transactions on S/390.
   4892      * The hotpatch features allows to prepare functions for hotpatching.
   4893        A certain amount of bytes is reserved before the function entry
   4894        label plus a NOP is inserted at its very beginning to implement a
   4895        backward jump when applying a patch. The feature can either be
   4896        enabled per compilation unit via the command-line option -mhotpatch
   4897        or per function using the hotpatch attribute.
   4898      * The shrink wrap optimization is now supported on S/390 and enabled
   4899        by default.
   4900      * A major rework of the routines to determine which registers need to
   4901        be saved and restored in function prologue/epilogue now allow to
   4902        use floating point registers as save slots. This will happen for
   4903        certain leaf function with -march=z10 or higher.
   4904      * The LRA rtl pass replaces reload by default on S/390.
   4905 
   4906   RX
   4907 
   4908      * The port now allows to specify the RX100, RX200, and RX600
   4909        processors with the command-line options -mcpu=rx100, -mcpu=rx200
   4910        and -mcpu=rx600.
   4911 
   4912   SH
   4913 
   4914      * Minor improvements to code generated for integer arithmetic and
   4915        code that involves the T bit.
   4916      * Added support for the SH2A clips and clipu instructions. The
   4917        compiler will now try to utilize them for min/max expressions such
   4918        as max (-128, min (127, x)).
   4919      * Added support for the cmp/str instruction through built-in
   4920        functions such as __builtin_strlen. When not optimizing for size,
   4921        the compiler will now expand calls to e.g. strlen as an inlined
   4922        sequences which utilize the cmp/str instruction.
   4923      * Improved code generated around volatile memory loads and stores.
   4924      * The option -mcbranchdi has been deprecated. Specifying it will
   4925        result in a warning and will not influence code generation.
   4926      * The option -mcmpeqdi has been deprecated. Specifying it will result
   4927        in a warning and will not influence code generation.
   4928 
   4929 GCC 4.9.1
   4930 
   4931    This is the [25]list of problem reports (PRs) from GCC's bug tracking
   4932    system that are known to be fixed in the 4.9.1 release. This list might
   4933    not be complete (that is, it is possible that some PRs that have been
   4934    fixed are not listed here).
   4935 
   4936    Version 4.0 of the OpenMP specification is supported even in Fortran,
   4937    not just C and C++.
   4938 
   4939 GCC 4.9.2
   4940 
   4941    This is the [26]list of problem reports (PRs) from GCC's bug tracking
   4942    system that are known to be fixed in the 4.9.2 release. This list might
   4943    not be complete (that is, it is possible that some PRs that have been
   4944    fixed are not listed here).
   4945 
   4946 GCC 4.9.3
   4947 
   4948    This is the [27]list of problem reports (PRs) from GCC's bug tracking
   4949    system that are known to be fixed in the 4.9.3 release. This list might
   4950    not be complete (that is, it is possible that some PRs that have been
   4951    fixed are not listed here).
   4952 
   4953 GCC 4.9.4
   4954 
   4955    This is the [28]list of problem reports (PRs) from GCC's bug tracking
   4956    system that are known to be fixed in the 4.9.4 release. This list might
   4957    not be complete (that is, it is possible that some PRs that have been
   4958    fixed are not listed here).
   4959 
   4960 
   4961     For questions related to the use of GCC, please consult these web
   4962     pages and the [29]GCC manuals. If that fails, the
   4963     [30]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   4964     web pages and the development of GCC are welcome on our developer
   4965     list at [31]gcc (a] gcc.gnu.org. All of [32]our lists have public
   4966     archives.
   4967 
   4968    Copyright (C) [33]Free Software Foundation, Inc. Verbatim copying and
   4969    distribution of this entire article is permitted in any medium,
   4970    provided this notice is preserved.
   4971 
   4972    These pages are [34]maintained by the GCC team. Last modified
   4973    2019-11-28[35].
   4974 
   4975 References
   4976 
   4977    1. https://gcc.gnu.org/ml/gcc-patches/2013-05/msg00728.html
   4978    2. https://gcc.gnu.org/PR60825
   4979    3. https://gcc.gnu.org/gcc-4.9/porting_to.html
   4980    4. https://www.openmp.org/specifications/
   4981    5. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Optimize-Options.html#index-fsimd-cost-model-908
   4982    6. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Language-Independent-Options.html#index-fdiagnostics-color-252
   4983    7. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Loop-Specific-Pragmas.html
   4984    8. https://www.cilkplus.org/
   4985    9. http://gcc.gnu.org/projects/cxx1y.html
   4986   10. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3638.html
   4987   11. http://gcc.gnu.org/projects/cxx1y.html
   4988   12. http://gcc.gnu.org/projects/cxx1y.html
   4989   13. http://gcc.gnu.org/projects/cxx1y.html
   4990   14. http://gcc.gnu.org/projects/cxx1y.html
   4991   15. http://gcc.gnu.org/projects/cxx1y.html
   4992   16. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3889.pdf
   4993   17. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/libstdc++/manual/manual/status.html#status.iso.2011
   4994   18. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2014
   4995   19. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Argument-passing-conventions.html
   4996   20. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/GNU-Fortran-Compiler-Directives.html
   4997   21. https://gcc.gnu.org/wiki/Fortran2003Status
   4998   22. https://gcc.gnu.org/wiki/Fortran2008Status
   4999   23. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gfortran/Debugging-Options.html
   5000   24. https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Function-Multiversioning.html
   5001   25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.1
   5002   26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.2
   5003   27. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.3
   5004   28. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.9.4
   5005   29. https://gcc.gnu.org/onlinedocs/
   5006   30. mailto:gcc-help (a] gcc.gnu.org
   5007   31. mailto:gcc (a] gcc.gnu.org
   5008   32. https://gcc.gnu.org/lists.html
   5009   33. https://www.fsf.org/
   5010   34. https://gcc.gnu.org/about.html
   5011   35. http://validator.w3.org/check/referer
   5012 ======================================================================
   5013 http://gcc.gnu.org/gcc-4.8/index.html
   5014                              GCC 4.8 Release Series
   5015 
   5016    (This release series is no longer supported.)
   5017 
   5018    June 23, 2015
   5019 
   5020    The [1]GNU project and the GCC developers are pleased to announce the
   5021    release of GCC 4.8.5.
   5022 
   5023    This release is a bug-fix release, containing fixes for regressions in
   5024    GCC 4.8.4 relative to previous releases of GCC.
   5025 
   5026 Release History
   5027 
   5028    GCC 4.8.5
   5029           June 23, 2015 ([2]changes, [3]documentation)
   5030 
   5031    GCC 4.8.4
   5032           December 19, 2014 ([4]changes, [5]documentation)
   5033 
   5034    GCC 4.8.3
   5035           May 22, 2014 ([6]changes, [7]documentation)
   5036 
   5037    GCC 4.8.2
   5038           October 16, 2013 ([8]changes, [9]documentation)
   5039 
   5040    GCC 4.8.1
   5041           May 31, 2013 ([10]changes, [11]documentation)
   5042 
   5043    GCC 4.8.0
   5044           March 22, 2013 ([12]changes, [13]documentation)
   5045 
   5046 References and Acknowledgements
   5047 
   5048    GCC used to stand for the GNU C Compiler, but since the compiler
   5049    supports several other languages aside from C, it now stands for the
   5050    GNU Compiler Collection.
   5051 
   5052    A list of [14]successful builds is updated as new information becomes
   5053    available.
   5054 
   5055    The GCC developers would like to thank the numerous people that have
   5056    contributed new features, improvements, bug fixes, and other changes as
   5057    well as test results to GCC. This [15]amazing group of volunteers is
   5058    what makes GCC successful.
   5059 
   5060    For additional information about GCC please refer to the [16]GCC
   5061    project web site or contact the [17]GCC development mailing list.
   5062 
   5063    To obtain GCC please use [18]our mirror sites or [19]our version
   5064    control system.
   5065 
   5066 
   5067     For questions related to the use of GCC, please consult these web
   5068     pages and the [20]GCC manuals. If that fails, the
   5069     [21]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   5070     web pages and the development of GCC are welcome on our developer
   5071     list at [22]gcc (a] gcc.gnu.org. All of [23]our lists have public
   5072     archives.
   5073 
   5074    Copyright (C) [24]Free Software Foundation, Inc. Verbatim copying and
   5075    distribution of this entire article is permitted in any medium,
   5076    provided this notice is preserved.
   5077 
   5078    These pages are [25]maintained by the GCC team. Last modified
   5079    2020-01-14[26].
   5080 
   5081 References
   5082 
   5083    1. http://www.gnu.org/
   5084    2. http://gcc.gnu.org/gcc-4.8/changes.html
   5085    3. https://gcc.gnu.org/onlinedocs/4.8.5/
   5086    4. http://gcc.gnu.org/gcc-4.8/changes.html
   5087    5. https://gcc.gnu.org/onlinedocs/4.8.4/
   5088    6. http://gcc.gnu.org/gcc-4.8/changes.html
   5089    7. https://gcc.gnu.org/onlinedocs/4.8.3/
   5090    8. http://gcc.gnu.org/gcc-4.8/changes.html
   5091    9. https://gcc.gnu.org/onlinedocs/4.8.2/
   5092   10. http://gcc.gnu.org/gcc-4.8/changes.html
   5093   11. https://gcc.gnu.org/onlinedocs/4.8.1/
   5094   12. http://gcc.gnu.org/gcc-4.8/changes.html
   5095   13. https://gcc.gnu.org/onlinedocs/4.8.0/
   5096   14. http://gcc.gnu.org/gcc-4.8/buildstat.html
   5097   15. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   5098   16. http://gcc.gnu.org/index.html
   5099   17. mailto:gcc (a] gcc.gnu.org
   5100   18. http://gcc.gnu.org/mirrors.html
   5101   19. http://gcc.gnu.org/git.html
   5102   20. https://gcc.gnu.org/onlinedocs/
   5103   21. mailto:gcc-help (a] gcc.gnu.org
   5104   22. mailto:gcc (a] gcc.gnu.org
   5105   23. https://gcc.gnu.org/lists.html
   5106   24. https://www.fsf.org/
   5107   25. https://gcc.gnu.org/about.html
   5108   26. http://validator.w3.org/check/referer
   5109 ======================================================================
   5110 http://gcc.gnu.org/gcc-4.8/changes.html
   5111                              GCC 4.8 Release Series
   5112                         Changes, New Features, and Fixes
   5113 
   5114 Caveats
   5115 
   5116    GCC now uses C++ as its implementation language. This means that to
   5117    build GCC from sources, you will need a C++ compiler that understands
   5118    C++ 2003. For more details on the rationale and specific changes,
   5119    please refer to the [1]C++ conversion page.
   5120 
   5121    To enable the Graphite framework for loop optimizations you now need
   5122    CLooG version 0.18.0 and ISL version 0.11.1. Both can be obtained from
   5123    the [2]GCC infrastructure directory. The installation manual contains
   5124    more information about requirements to build GCC.
   5125 
   5126    GCC now uses a more aggressive analysis to derive an upper bound for
   5127    the number of iterations of loops using constraints imposed by language
   5128    standards. This may cause non-conforming programs to no longer work as
   5129    expected, such as SPEC CPU 2006 464.h264ref and 416.gamess. A new
   5130    option, -fno-aggressive-loop-optimizations, was added to disable this
   5131    aggressive analysis. In some loops that have known constant number of
   5132    iterations, but undefined behavior is known to occur in the loop before
   5133    reaching or during the last iteration, GCC will warn about the
   5134    undefined behavior in the loop instead of deriving lower upper bound of
   5135    the number of iterations for the loop. The warning can be disabled with
   5136    -Wno-aggressive-loop-optimizations.
   5137 
   5138    On ARM, a bug has been fixed in GCC's implementation of the AAPCS rules
   5139    for the layout of vectors that could lead to wrong code being
   5140    generated. Vectors larger than 8 bytes in size are now by default
   5141    aligned to an 8-byte boundary. This is an ABI change: code that makes
   5142    explicit use of vector types may be incompatible with binary objects
   5143    built with older versions of GCC. Auto-vectorized code is not affected
   5144    by this change.
   5145 
   5146    On AVR, support has been removed for the command-line option
   5147    -mshort-calls deprecated in GCC 4.7.
   5148 
   5149    On AVR, the configure option --with-avrlibc supported since GCC 4.7.2
   5150    is turned on per default for all non-RTEMS configurations. This option
   5151    arranges for a better integration of [3]AVR Libc with avr-gcc. For
   5152    technical details, see [4]PR54461. To turn off the option in non-RTEMS
   5153    configurations, use --with-avrlibc=no. If the compiler is configured
   5154    for RTEMS, the option is always turned off.
   5155 
   5156    More information on porting to GCC 4.8 from previous versions of GCC
   5157    can be found in the [5]porting guide for this release.
   5158 
   5159 General Optimizer Improvements (and Changes)
   5160 
   5161      * DWARF4 is now the default when generating DWARF debug information.
   5162        When -g is used on a platform that uses DWARF debugging
   5163        information, GCC will now default to -gdwarf-4
   5164        -fno-debug-types-section.
   5165        GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information
   5166        consumers support DWARF4 by default. Before GCC 4.8 the default
   5167        version used was DWARF2. To make GCC 4.8 generate an older DWARF
   5168        version use -g together with -gdwarf-2 or -gdwarf-3. The default
   5169        for Darwin and VxWorks is still -gdwarf-2 -gstrict-dwarf.
   5170      * A new general optimization level, -Og, has been introduced. It
   5171        addresses the need for fast compilation and a superior debugging
   5172        experience while providing a reasonable level of run-time
   5173        performance. Overall experience for development should be better
   5174        than the default optimization level -O0.
   5175      * A new option -ftree-partial-pre was added to control the partial
   5176        redundancy elimination (PRE) optimization. This option is enabled
   5177        by default at the -O3 optimization level, and it makes PRE more
   5178        aggressive.
   5179      * The option -fconserve-space has been removed; it was no longer
   5180        useful on most targets since GCC supports putting variables into
   5181        BSS without making them common.
   5182      * The struct reorg and matrix reorg optimizations (command-line
   5183        options -fipa-struct-reorg and -fipa-matrix-reorg) have been
   5184        removed. They did not always work correctly, nor did they work with
   5185        link-time optimization (LTO), hence were only applicable to
   5186        programs consisting of a single translation unit.
   5187      * Several scalability bottle-necks have been removed from GCC's
   5188        optimization passes. Compilation of extremely large functions, e.g.
   5189        due to the use of the flatten attribute in the "Eigen" C++ linear
   5190        algebra templates library, is significantly faster than previous
   5191        releases of GCC.
   5192      * Link-time optimization (LTO) improvements:
   5193           + LTO partitioning has been rewritten for better reliability and
   5194             maintanibility. Several important bugs leading to link
   5195             failures have been fixed.
   5196      * Interprocedural optimization improvements:
   5197           + A new symbol table has been implemented. It builds on existing
   5198             callgraph and varpool modules and provide a new API. Unusual
   5199             symbol visibilities and aliases are handled more consistently
   5200             leading to, for example, more aggressive unreachable code
   5201             removal with LTO.
   5202           + The inline heuristic can now bypass limits on the size of of
   5203             inlined functions when the inlining is particularly
   5204             profitable. This happens, for example, when loop bounds or
   5205             array strides get propagated.
   5206           + Values passed through aggregates (either by value or
   5207             reference) are now propagated at the inter-procedural level
   5208             leading to better inlining decisions (for example in the case
   5209             of Fortran array descriptors) and devirtualization.
   5210      * [6]AddressSanitizer , a fast memory error detector, has been added
   5211        and can be enabled via -fsanitize=address. Memory access
   5212        instructions will be instrumented to detect heap-, stack-, and
   5213        global-buffer overflow as well as use-after-free bugs. To get nicer
   5214        stacktraces, use -fno-omit-frame-pointer. The AddressSanitizer is
   5215        available on IA-32/x86-64/x32/PowerPC/PowerPC64 GNU/Linux and on
   5216        x86-64 Darwin.
   5217      * [7]ThreadSanitizer has been added and can be enabled via
   5218        -fsanitize=thread. Instructions will be instrumented to detect data
   5219        races. The ThreadSanitizer is available on x86-64 GNU/Linux.
   5220      * A new local register allocator (LRA) has been implemented, which
   5221        replaces the 26 year old reload pass and improves generated code
   5222        quality. For now it is active on the IA-32 and x86-64 targets.
   5223      * Support for transactional memory has been implemented on the
   5224        following architectures: IA-32/x86-64, ARM, PowerPC, SH, SPARC, and
   5225        Alpha.
   5226 
   5227 New Languages and Language specific improvements
   5228 
   5229   C family
   5230 
   5231      * Each diagnostic emitted now includes the original source line and a
   5232        caret '^' indicating the column. The option
   5233        -fno-diagnostics-show-caret suppresses this information.
   5234      * The option -ftrack-macro-expansion=2 is now enabled by default.
   5235        This allows the compiler to display the macro expansion stack in
   5236        diagnostics. Combined with the caret information, an example
   5237        diagnostic showing these two features is:
   5238 
   5239 t.c:1:94: error: invalid operands to binary < (have struct mystruct and float
   5240 )
   5241  #define MYMAX(A,B)    __extension__ ({ __typeof__(A) __a = (A); __typeof__(B) _
   5242 _b = (B); __a < __b ? __b : __a; })
   5243 
   5244               ^
   5245 t.c:7:7: note: in expansion of macro 'MYMAX'
   5246    X = MYMAX(P, F);
   5247        ^
   5248 
   5249      * A new -Wsizeof-pointer-memaccess warning has been added (also
   5250        enabled by -Wall) to warn about suspicious length parameters to
   5251        certain string and memory built-in functions if the argument uses
   5252        sizeof. This warning warns e.g. about memset (ptr, 0, sizeof
   5253        (ptr)); if ptr is not an array, but a pointer, and suggests a
   5254        possible fix, or about memcpy (&foo, ptr, sizeof (&foo));.
   5255      * The new option -Wpedantic is an alias for -pedantic, which is now
   5256        deprecated. The forms -Wno-pedantic, -Werror=pedantic, and
   5257        -Wno-error=pedantic work in the same way as for any other -W
   5258        option. One caveat is that -Werror=pedantic is not equivalent to
   5259        -pedantic-errors, since the latter makes into errors some warnings
   5260        that are not controlled by -Wpedantic, and the former only affects
   5261        diagnostics that are disabled when using -Wno-pedantic.
   5262      * The option -Wshadow no longer warns if a declaration shadows a
   5263        function declaration, unless the former declares a function or
   5264        pointer to function, because this is [8]a common and valid case in
   5265        real-world code.
   5266 
   5267   C++
   5268 
   5269      * G++ now implements the [9]C++11 thread_local keyword; this differs
   5270        from the GNU __thread keyword primarily in that it allows dynamic
   5271        initialization and destruction semantics. Unfortunately, this
   5272        support requires a run-time penalty for references to
   5273        non-function-local thread_local variables defined in a different
   5274        translation unit even if they don't need dynamic initialization, so
   5275        users may want to continue to use __thread for TLS variables with
   5276        static initialization semantics.
   5277        If the programmer can be sure that no use of the variable in a
   5278        non-defining TU needs to trigger dynamic initialization (either
   5279        because the variable is statically initialized, or a use of the
   5280        variable in the defining TU will be executed before any uses in
   5281        another TU), they can avoid this overhead with the
   5282        -fno-extern-tls-init option.
   5283        OpenMP threadprivate variables now also support dynamic
   5284        initialization and destruction by the same mechanism.
   5285      * G++ now implements the [10]C++11 attribute syntax, e.g.
   5286 
   5287 [[noreturn]] void f();
   5288 
   5289        and also the alignment specifier, e.g.
   5290 
   5291 alignas(double) int i;
   5292 
   5293      * G++ now implements [11]C++11 inheriting constructors, e.g.
   5294 
   5295 struct A { A(int); };
   5296 struct B: A { using A::A; }; // defines B::B(int)
   5297 B b(42); // OK
   5298 
   5299      * As of GCC 4.8.1, G++ implements the change to decltype semantics
   5300        from [12]N3276.
   5301 
   5302 struct A f();
   5303 decltype(f()) g();    // OK, return type of f() is not required to be complete.
   5304 
   5305      * As of GCC 4.8.1, G++ implements [13]C++11 ref-qualifiers, e.g.
   5306 
   5307 struct A { int f() &; };
   5308 int i = A().f();  // error, f() requires an lvalue object
   5309 
   5310      * G++ now supports a -std=c++1y option for experimentation with
   5311        features proposed for the next revision of the standard, expected
   5312        around 2014. Currently the only difference from -std=c++11 is
   5313        support for return type deduction in normal functions, as proposed
   5314        in [14]N3386. Status of C++1y features in GCC 4.8 can be found
   5315        [15]here.
   5316      * The G++ namespace association extension, __attribute ((strong)),
   5317        has been deprecated. Inline namespaces should be used instead.
   5318      * G++ now supports a -fext-numeric-literal option to control whether
   5319        GNU numeric literal suffixes are accepted as extensions or
   5320        processed as C++11 user-defined numeric literal suffixes. The flag
   5321        is on (use suffixes for GNU literals) by default for -std=gnu++*,
   5322        and -std=c++98. The flag is off (use suffixes for user-defined
   5323        literals) by default for -std=c++11 and later.
   5324 
   5325     Runtime Library (libstdc++)
   5326 
   5327      * [16]Improved experimental support for the new ISO C++ standard,
   5328        C++11, including:
   5329           + forward_list meets the allocator-aware container requirements;
   5330           + this_thread::sleep_for(), this_thread::sleep_until() and
   5331             this_thread::yield() are defined without requiring the
   5332             configure option --enable-libstdcxx-time;
   5333      * Improvements to <random>:
   5334           + SSE optimized normal_distribution.
   5335           + Use of hardware RNG instruction for random_device on new x86
   5336             processors (requires the assembler to support the
   5337             instruction.)
   5338        and <ext/random>:
   5339           + New random number engine simd_fast_mersenne_twister_engine
   5340             with an optimized SSE implementation.
   5341           + New random number distributions beta_distribution,
   5342             normal_mv_distribution, rice_distribution,
   5343             nakagami_distribution, pareto_distribution, k_distribution,
   5344             arcsine_distribution, hoyt_distribution.
   5345      * Added --disable-libstdcxx-verbose configure option to disable
   5346        diagnostic messages issued when a process terminates abnormally.
   5347        This may be useful for embedded systems to reduce the size of
   5348        executables that link statically to the library.
   5349 
   5350   Fortran
   5351 
   5352      * Compatibility notice:
   5353           + Module files: The version of module files (.mod) has been
   5354             incremented. Fortran MODULEs compiled by earlier GCC versions
   5355             have to be recompiled, when they are USEd by files compiled
   5356             with GCC 4.8. GCC 4.8 is not able to read .mod files created
   5357             by earlier versions; attempting to do so gives an error
   5358             message.
   5359             Note: The ABI of the produced assembler data itself has not
   5360             changed; object files and libraries are fully compatible with
   5361             older versions except as noted below.
   5362           + ABI: Some internal names (used in the assembler/object file)
   5363             have changed for symbols declared in the specification part of
   5364             a module. If an affected module  or a file using it via use
   5365             association  is recompiled, the module and all files which
   5366             directly use such symbols have to be recompiled as well. This
   5367             change only affects the following kind of module symbols:
   5368                o Procedure pointers. Note: C-interoperable function
   5369                  pointers (type(c_funptr)) are not affected nor are
   5370                  procedure-pointer components.
   5371                o Deferred-length character strings.
   5372      * The [17]BACKTRACE intrinsic subroutine has been added. It shows a
   5373        backtrace at an arbitrary place in user code; program execution
   5374        continues normally afterwards.
   5375      * The [18]-Wc-binding-type warning option has been added (disabled by
   5376        default). It warns if the a variable might not be C interoperable;
   5377        in particular, if the variable has been declared using an intrinsic
   5378        type with default kind instead of using a kind parameter defined
   5379        for C interoperability in the intrinsic ISO_C_Binding module.
   5380        Before, this warning was always printed. The -Wc-binding-type
   5381        option is enabled by -Wall.
   5382      * The [19]-Wrealloc-lhs and -Wrealloc-lhs-all warning command-line
   5383        options have been added, which diagnose when code is inserted for
   5384        automatic (re)allocation of a variable during assignment. This
   5385        option can be used to decide whether it is safe to use
   5386        [20]-fno-realloc-lhs. Additionally, it can be used to find
   5387        automatic (re)allocation in hot loops. (For arrays, replacing
   5388        "var=" by "var(:)=" disables the automatic reallocation.)
   5389      * The [21]-Wcompare-reals command-line option has been added. When
   5390        this is set, warnings are issued when comparing REAL or COMPLEX
   5391        types for equality and inequality; consider replacing a == b by
   5392        abs(ab) < eps with a suitable eps. -Wcompare-reals is enabled by
   5393        -Wextra.
   5394      * The [22]-Wtarget-lifetime command-line option has been added
   5395        (enabled with -Wall), which warns if the pointer in a pointer
   5396        assignment might outlive its target.
   5397      * Reading floating point numbers which use "q" for the exponential
   5398        (such as 4.0q0) is now supported as vendor extension for better
   5399        compatibility with old data files. It is strongly recommended to
   5400        use for I/O the equivalent but standard conforming "e" (such as
   5401        4.0e0).
   5402        (For Fortran source code, consider replacing the "q" in
   5403        floating-point literals by a kind parameter (e.g. 4.0e0_qp with a
   5404        suitable qp). Note that  in Fortran source code  replacing "q" by
   5405        a simple "e" is not equivalent.)
   5406      * The GFORTRAN_TMPDIR environment variable for specifying a
   5407        non-default directory for files opened with STATUS="SCRATCH", is
   5408        not used anymore. Instead gfortran checks the POSIX/GNU standard
   5409        TMPDIR environment variable. If TMPDIR is not defined, gfortran
   5410        falls back to other methods to determine the directory for
   5411        temporary files as documented in the [23]user manual.
   5412      * [24]Fortran 2003:
   5413           + Support for unlimited polymorphic variables (CLASS(*)) has
   5414             been added. Nonconstant character lengths are not yet
   5415             supported.
   5416      * [25]TS 29113:
   5417           + Assumed types (TYPE(*)) are now supported.
   5418           + Experimental support for assumed-rank arrays (dimension(..))
   5419             has been added. Note that currently gfortran's own array
   5420             descriptor is used, which is different from the one defined in
   5421             TS29113, see [26]gfortran's header file or use the [27]Chasm
   5422             Language Interoperability Tools.
   5423 
   5424   Go
   5425 
   5426      * GCC 4.8.2 provides a complete implementation of the Go 1.1.2
   5427        release.
   5428      * GCC 4.8.0 and 4.8.1 implement a preliminary version of the Go 1.1
   5429        release. The library support is not quite complete.
   5430      * Go has been tested on GNU/Linux and Solaris platforms for various
   5431        processors including x86, x86_64, PowerPC, SPARC, and Alpha. It may
   5432        work on other platforms as well.
   5433 
   5434 New Targets and Target Specific Improvements
   5435 
   5436   AArch64
   5437 
   5438      * A new port has been added to support AArch64, the new 64-bit
   5439        architecture from ARM. Note that this is a separate port from the
   5440        existing 32-bit ARM port.
   5441      * The port provides initial support for the Cortex-A53 and the
   5442        Cortex-A57 processors with the command line options
   5443        -mcpu=cortex-a53 and -mcpu=cortex-a57.
   5444      * As of GCC 4.8.4 a workaround for the ARM Cortex-A53 erratum 835769
   5445        has been added and can be enabled by giving the
   5446        -mfix-cortex-a53-835769 option. Alternatively it can be enabled by
   5447        default by configuring GCC with the --enable-fix-cortex-a53-835769
   5448        option.
   5449 
   5450   ARM
   5451 
   5452      * Initial support has been added for the AArch32 extensions defined
   5453        in the ARMv8 architecture.
   5454      * Code generation improvements for the Cortex-A7 and Cortex-A15 CPUs.
   5455      * A new option, -mcpu=marvell-pj4, has been added to generate code
   5456        for the Marvell PJ4 processor.
   5457      * The compiler can now automatically generate the VFMA, VFMS, REVSH
   5458        and REV16 instructions.
   5459      * A new vectorizer cost model for Advanced SIMD configurations to
   5460        improve the auto-vectorization strategies used.
   5461      * The scheduler now takes into account the number of live registers
   5462        to reduce the amount of spilling that can occur. This should
   5463        improve code performance in large functions. The limit can be
   5464        removed by using the option -fno-sched-pressure.
   5465      * Improvements have been made to the Marvell iWMMX code generation
   5466        and support for the iWMMX2 SIMD unit has been added. The option
   5467        -mcpu=iwmmxt2 can be used to enable code generation for the latter.
   5468      * A number of code generation improvements for Thumb2 to reduce code
   5469        size when compiling for the M-profile processors.
   5470      * The RTEMS (arm-rtems) port has been updated to use the EABI.
   5471      * Code generation support for the old FPA and Maverick floating-point
   5472        architectures has been removed. Ports that previously relied on
   5473        these features have also been removed. This includes the targets:
   5474           + arm*-*-linux-gnu (use arm*-*-linux-gnueabi)
   5475           + arm*-*-elf (use arm*-*-eabi)
   5476           + arm*-*-uclinux* (use arm*-*-uclinux*eabi)
   5477           + arm*-*-ecos-elf (no alternative)
   5478           + arm*-*-freebsd (no alternative)
   5479           + arm*-wince-pe* (no alternative).
   5480 
   5481   AVR
   5482 
   5483      * Support for the "Embedded C" fixed-point has been added. For
   5484        details, see the [28]GCC wiki and the [29]user manual. The support
   5485        is not complete.
   5486      * A new print modifier %r for register operands in inline assembler
   5487        is supported. It will print the raw register number without the
   5488        register prefix 'r':
   5489     /* Return the most significant byte of 'val', a 64-bit value.  */
   5490 
   5491     unsigned char msb (long long val)
   5492     {
   5493       unsigned char c;
   5494       __asm__ ("mov %0, %r1+7" : "=r" (c) : "r" (val));
   5495       return c;
   5496     }
   5497        The inline assembler in this example will generate code like
   5498     mov r24, 8+7
   5499        provided c is allocated to R24 and val is allocated to R8R15. This
   5500        works because the GNU assembler accepts plain register numbers
   5501        without register prefix.
   5502      * Static initializers with 3-byte symbols are supported now:
   5503     extern const __memx char foo;
   5504     const __memx void *pfoo = &foo;
   5505        This requires at least Binutils 2.23.
   5506 
   5507   IA-32/x86-64
   5508 
   5509      * Allow -mpreferred-stack-boundary=3 for the x86-64 architecture with
   5510        SSE extensions disabled. Since the x86-64 ABI requires 16 byte
   5511        stack alignment, this is ABI incompatible and intended to be used
   5512        in controlled environments where stack space is an important
   5513        limitation. This option will lead to wrong code when functions
   5514        compiled with 16 byte stack alignment (such as functions from a
   5515        standard library) are called with misaligned stack. In this case,
   5516        SSE instructions may lead to misaligned memory access traps. In
   5517        addition, variable arguments will be handled incorrectly for 16
   5518        byte aligned objects (including x87 long double and __int128),
   5519        leading to wrong results. You must build all modules with
   5520        -mpreferred-stack-boundary=3, including any libraries. This
   5521        includes the system libraries and startup modules.
   5522      * Support for the new Intel processor codename Broadwell with RDSEED,
   5523        ADCX, ADOX, PREFETCHW is available through -madx, -mprfchw,
   5524        -mrdseed command-line options.
   5525      * Support for the Intel RTM and HLE intrinsics, built-in functions
   5526        and code generation is available via -mrtm and -mhle.
   5527      * Support for the Intel FXSR, XSAVE and XSAVEOPT instruction sets.
   5528        Intrinsics and built-in functions are available via -mfxsr, -mxsave
   5529        and -mxsaveopt respectively.
   5530      * New -maddress-mode=[short|long] options for x32.
   5531        -maddress-mode=short overrides default 64-bit addresses to 32-bit
   5532        by emitting the 0x67 address-size override prefix. This is the
   5533        default address mode for x32.
   5534      * New built-in functions to detect run-time CPU type and ISA:
   5535           + A built-in function __builtin_cpu_is has been added to detect
   5536             if the run-time CPU is of a particular type. It returns a
   5537             positive integer on a match and zero otherwise. It accepts one
   5538             string literal argument, the CPU name. For example,
   5539             __builtin_cpu_is("westmere") returns a positive integer if the
   5540             run-time CPU is an Intel Core i7 Westmere processor. Please
   5541             refer to the [30]user manual for the list of valid CPU names
   5542             recognized.
   5543           + A built-in function __builtin_cpu_supports has been added to
   5544             detect if the run-time CPU supports a particular ISA feature.
   5545             It returns a positive integer on a match and zero otherwise.
   5546             It accepts one string literal argument, the ISA feature. For
   5547             example, __builtin_cpu_supports("ssse3") returns a positive
   5548             integer if the run-time CPU supports SSSE3 instructions.
   5549             Please refer to the [31]user manual for the list of valid ISA
   5550             names recognized.
   5551        Caveat: If these built-in functions are called before any static
   5552        constructors are invoked, like during IFUNC initialization, then
   5553        the CPU detection initialization must be explicitly run using this
   5554        newly provided built-in function, __builtin_cpu_init. The
   5555        initialization needs to be done only once. For example, this is how
   5556        the invocation would look like inside an IFUNC initializer:
   5557     static void (*some_ifunc_resolver(void))(void)
   5558     {
   5559       __builtin_cpu_init();
   5560       if (__builtin_cpu_is("amdfam10h") ...
   5561       if (__builtin_cpu_supports("popcnt") ...
   5562     }
   5563 
   5564      * Function Multiversioning Support with G++:
   5565        It is now possible to create multiple function versions each
   5566        targeting a specific processor and/or ISA. Function versions have
   5567        the same signature but different target attributes. For example,
   5568        here is a program with function versions:
   5569     __attribute__ ((target ("default")))
   5570     int foo(void)
   5571     {
   5572       return 1;
   5573     }
   5574 
   5575     __attribute__ ((target ("sse4.2")))
   5576     int foo(void)
   5577     {
   5578       return 2;
   5579     }
   5580 
   5581     int main (void)
   5582     {
   5583       int (*p) = &foo;
   5584       assert ((*p)() == foo());
   5585       return 0;
   5586     }
   5587 
   5588        Please refer to this [32]wiki for more information.
   5589      * The x86 back end has been improved to allow option -fschedule-insns
   5590        to work reliably. This option can be used to schedule instructions
   5591        better and leads to improved performace in certain cases.
   5592      * Windows MinGW-w64 targets (*-w64-mingw*) require at least r5437
   5593        from the Mingw-w64 trunk.
   5594      * Support for new AMD family 15h processors (Steamroller core) is now
   5595        available through the -march=bdver3 and -mtune=bdver3 options.
   5596      * Support for new AMD family 16h processors (Jaguar core) is now
   5597        available through the -march=btver2 and -mtune=btver2 options.
   5598 
   5599   FRV
   5600 
   5601      * This target now supports the -fstack-usage command-line option.
   5602 
   5603   MIPS
   5604 
   5605      * GCC can now generate code specifically for the R4700, Broadcom XLP
   5606        and MIPS 34kn processors. The associated -march options are
   5607        -march=r4700, -march=xlp and -march=34kn respectively.
   5608      * GCC now generates better DSP code for MIPS 74k cores thanks to
   5609        further scheduling optimizations.
   5610      * The MIPS port now supports the -fstack-check option.
   5611      * GCC now passes the -mmcu and -mno-mcu options to the assembler.
   5612      * Previous versions of GCC would silently accept -fpic and -fPIC for
   5613        -mno-abicalls targets like mips*-elf. This combination was not
   5614        intended or supported, and did not generate position-independent
   5615        code. GCC 4.8 now reports an error when this combination is used.
   5616 
   5617   PowerPC / PowerPC64 / RS6000
   5618 
   5619      * SVR4 configurations (GNU/Linux, FreeBSD, NetBSD) no longer save,
   5620        restore or update the VRSAVE register by default. The respective
   5621        operating systems manage the VRSAVE register directly.
   5622      * Large TOC support has been added for AIX through the command line
   5623        option -mcmodel=large.
   5624      * Native Thread-Local Storage support has been added for AIX.
   5625      * VMX (Altivec) and VSX instruction sets now are enabled implicitly
   5626        when targetting processors that support those hardware features on
   5627        AIX 6.1 and above.
   5628 
   5629   RX
   5630 
   5631      * This target will now issue a warning message whenever multiple fast
   5632        interrupt handlers are found in the same compilation unit. This
   5633        feature can be turned off by the new
   5634        -mno-warn-multiple-fast-interrupts command-line option.
   5635 
   5636   S/390, System z
   5637 
   5638      * Support for the IBM zEnterprise zEC12 processor has been added.
   5639        When using the -march=zEC12 option, the compiler will generate code
   5640        making use of the following new instructions:
   5641           + load and trap instructions
   5642           + 2 new compare and trap instructions
   5643           + rotate and insert selected bits - without CC clobber
   5644        The -mtune=zEC12 option enables zEC12 specific instruction
   5645        scheduling without making use of new instructions.
   5646      * Register pressure sensitive instruction scheduling is enabled by
   5647        default.
   5648      * The ifunc function attribute is enabled by default.
   5649      * memcpy and memcmp invokations on big memory chunks or with run time
   5650        lengths are not generated inline anymore when tuning for z10 or
   5651        higher. The purpose is to make use of the IFUNC optimized versions
   5652        in Glibc.
   5653 
   5654   SH
   5655 
   5656      * The default alignment settings have been reduced to be less
   5657        aggressive. This results in more compact code for optimization
   5658        levels other than -Os.
   5659      * Improved support for the __atomic built-in functions:
   5660           + A new option -matomic-model=model selects the model for the
   5661             generated atomic sequences. The following models are
   5662             supported:
   5663 
   5664               soft-gusa
   5665                       Software gUSA sequences (SH3* and SH4* only). On
   5666                       SH4A targets this will now also partially utilize
   5667                       the movco.l and movli.l instructions. This is the
   5668                       default when the target is sh3*-*-linux* or
   5669                       sh4*-*-linux*.
   5670 
   5671               hard-llcs
   5672                       Hardware movco.l / movli.l sequences (SH4A only).
   5673 
   5674               soft-tcb
   5675                       Software thread control block sequences.
   5676 
   5677               soft-imask
   5678                       Software interrupt flipping sequences (privileged
   5679                       mode only). This is the default when the target is
   5680                       sh1*-*-linux* or sh2*-*-linux*.
   5681 
   5682               none
   5683                       Generates function calls to the respective __atomic
   5684                       built-in functions. This is the default for SH64
   5685                       targets or when the target is not sh*-*-linux*.
   5686 
   5687           + The option -msoft-atomic has been deprecated. It is now an
   5688             alias for -matomic-model=soft-gusa.
   5689           + A new option -mtas makes the compiler generate the tas.b
   5690             instruction for the __atomic_test_and_set built-in function
   5691             regardless of the selected atomic model.
   5692           + The __sync functions in libgcc now reflect the selected atomic
   5693             model when building the toolchain.
   5694      * Added support for the mov.b and mov.w instructions with
   5695        displacement addressing.
   5696      * Added support for the SH2A instructions movu.b and movu.w.
   5697      * Various improvements to code generated for integer arithmetic.
   5698      * Improvements to conditional branches and code that involves the T
   5699        bit. A new option -mzdcbranch tells the compiler to favor
   5700        zero-displacement branches. This is enabled by default for SH4*
   5701        targets.
   5702      * The pref instruction will now be emitted by the __builtin_prefetch
   5703        built-in function for SH3* targets.
   5704      * The fmac instruction will now be emitted by the fmaf standard
   5705        function and the __builtin_fmaf built-in function.
   5706      * The -mfused-madd option has been deprecated in favor of the
   5707        machine-independent -ffp-contract option. Notice that the fmac
   5708        instruction will now be generated by default for expressions like a
   5709        * b + c. This is due to the compiler default setting
   5710        -ffp-contract=fast.
   5711      * Added new options -mfsrra and -mfsca to allow the compiler using
   5712        the fsrra and fsca instructions on targets other than SH4A (where
   5713        they are already enabled by default).
   5714      * Added support for the __builtin_bswap32 built-in function. It is
   5715        now expanded as a sequence of swap.b and swap.w instructions
   5716        instead of a library function call.
   5717      * The behavior of the -mieee option has been fixed and the negative
   5718        form -mno-ieee has been added to control the IEEE conformance of
   5719        floating point comparisons. By default -mieee is now enabled and
   5720        the option -ffinite-math-only implicitly sets -mno-ieee.
   5721      * Added support for the built-in functions __builtin_thread_pointer
   5722        and __builtin_set_thread_pointer. This assumes that GBR is used to
   5723        hold the thread pointer of the current thread. Memory loads and
   5724        stores relative to the address returned by __builtin_thread_pointer
   5725        will now also utilize GBR based displacement address modes.
   5726      * The -mdiv= option for targets other than SHmedia has been fixed and
   5727        documented.
   5728 
   5729   SPARC
   5730 
   5731      * Added optimized instruction scheduling for Niagara4.
   5732 
   5733   TILE-Gx
   5734 
   5735      * Added support for the -mcmodel=MODEL command-line option. The
   5736        models supported are small and large.
   5737 
   5738   V850
   5739 
   5740      * This target now supports the E3V5 architecture via the use of the
   5741        new -mv850e3v5 command-line option. It also has experimental
   5742        support for the e3v5 LOOP instruction which can be enabled via the
   5743        new -mloop command-line option.
   5744 
   5745   XStormy16
   5746 
   5747      * This target now supports the -fstack-usage command-line option.
   5748 
   5749 Operating Systems
   5750 
   5751   OpenBSD
   5752 
   5753      * Support for OpenBSD/amd64 (x86_64-*-openbsd*) has been added and
   5754        support for OpenBSD/i386 (i386-*-openbsd*) has been rejuvenated.
   5755 
   5756   Windows (Cygwin)
   5757 
   5758      * Executables are now linked against shared libgcc by default. The
   5759        previous default was to link statically, which can still be done by
   5760        explicitly specifying -static or static-libgcc on the command line.
   5761        However it is strongly advised against, as it will cause problems
   5762        for any application that makes use of DLLs compiled by GCC. It
   5763        should be alright for a monolithic stand-alone application that
   5764        only links against the Windows DLLs, but offers little or no
   5765        benefit.
   5766 
   5767 GCC 4.8.1
   5768 
   5769    This is the [33]list of problem reports (PRs) from GCC's bug tracking
   5770    system that are known to be fixed in the 4.8.1 release. This list might
   5771    not be complete (that is, it is possible that some PRs that have been
   5772    fixed are not listed here).
   5773 
   5774    The C++11 <chrono> std::chrono::system_clock and
   5775    std::chrono::steady_clock classes have changed ABI in GCC 4.8.1, they
   5776    both are now separate (never typedefs of each other), both use
   5777    std::chrono::nanoseconds resolution, on most GNU/Linux configurations
   5778    std::chrono::steady_clock is now finally monotonic, and both classes
   5779    are mangled differently than in the previous GCC releases.
   5780    std::chrono::system_clock::now() with std::chrono::microseconds resp.
   5781    std::chrono::seconds resolution is still exported for backwards
   5782    compatibility with default configured libstdc++. Note that libstdc++
   5783    configured with --enable-libstdcxx-time= used to be ABI incompatible
   5784    with default configured libstdc++ for those two classes and no ABI
   5785    compatibility can be offered for those configurations, so any C++11
   5786    code that uses those classes and has been compiled and linked against
   5787    libstdc++ configured with the non-default --enable-libstdcxx-time=
   5788    configuration option needs to be recompiled.
   5789 
   5790 GCC 4.8.2
   5791 
   5792    This is the [34]list of problem reports (PRs) from GCC's bug tracking
   5793    system that are known to be fixed in the 4.8.2 release. This list might
   5794    not be complete (that is, it is possible that some PRs that have been
   5795    fixed are not listed here).
   5796 
   5797 GCC 4.8.3
   5798 
   5799    This is the [35]list of problem reports (PRs) from GCC's bug tracking
   5800    system that are known to be fixed in the 4.8.3 release. This list might
   5801    not be complete (that is, it is possible that some PRs that have been
   5802    fixed are not listed here).
   5803 
   5804    Support for the new powerpc64le-linux platform has been added. It
   5805    defaults to generating code that conforms to the ELFV2 ABI.
   5806 
   5807 GCC 4.8.4
   5808 
   5809    This is the [36]list of problem reports (PRs) from GCC's bug tracking
   5810    system that are known to be fixed in the 4.8.4 release. This list might
   5811    not be complete (that is, it is possible that some PRs that have been
   5812    fixed are not listed here).
   5813 
   5814 GCC 4.8.5
   5815 
   5816    This is the [37]list of problem reports (PRs) from GCC's bug tracking
   5817    system that are known to be fixed in the 4.8.5 release. This list might
   5818    not be complete (that is, it is possible that some PRs that have been
   5819    fixed are not listed here).
   5820 
   5821 
   5822     For questions related to the use of GCC, please consult these web
   5823     pages and the [38]GCC manuals. If that fails, the
   5824     [39]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   5825     web pages and the development of GCC are welcome on our developer
   5826     list at [40]gcc (a] gcc.gnu.org. All of [41]our lists have public
   5827     archives.
   5828 
   5829    Copyright (C) [42]Free Software Foundation, Inc. Verbatim copying and
   5830    distribution of this entire article is permitted in any medium,
   5831    provided this notice is preserved.
   5832 
   5833    These pages are [43]maintained by the GCC team. Last modified
   5834    2019-11-28[44].
   5835 
   5836 References
   5837 
   5838    1. https://gcc.gnu.org/wiki/cxx-conversion
   5839    2. ftp://gcc.gnu.org/pub/gcc/infrastructure/
   5840    3. http://www.nongnu.org/avr-libc/
   5841    4. https://gcc.gnu.org/PR54461
   5842    5. https://gcc.gnu.org/gcc-4.8/porting_to.html
   5843    6. https://github.com/google/sanitizers
   5844    7. https://code.google.com/archive/p/data-race-test/wikis/ThreadSanitizer.wiki
   5845    8. https://lkml.org/lkml/2006/11/28/239
   5846    9. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html
   5847   10. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html
   5848   11. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html
   5849   12. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3276.pdf
   5850   13. http://gcc.gnu.org/gcc-4.8/cxx0x_status.html
   5851   14. http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3386.html
   5852   15. http://gcc.gnu.org/projects/cxx1y.html
   5853   16. https://gcc.gnu.org/onlinedocs/gcc-4.8.4/libstdc++/manual/manual/status.html#status.iso.2011
   5854   17. https://gcc.gnu.org/onlinedocs/gfortran/BACKTRACE.html
   5855   18. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html
   5856   19. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html
   5857   20. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html
   5858   21. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html
   5859   22. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html
   5860   23. https://gcc.gnu.org/onlinedocs/gfortran/TMPDIR.html
   5861   24. https://gcc.gnu.org/wiki/Fortran2003Status
   5862   25. https://gcc.gnu.org/wiki/TS29113Status
   5863   26. https://gcc.gnu.org/viewcvs/trunk/libgfortran/libgfortran.h?content-type=text/plain&view=co
   5864   27. http://chasm-interop.sourceforge.net/
   5865   28. https://gcc.gnu.org/wiki/avr-gcc#Fixed-Point_Support
   5866   29. https://gcc.gnu.org/onlinedocs/gcc/Fixed-Point.html
   5867   30. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html
   5868   31. https://gcc.gnu.org/onlinedocs/gcc/x86-Built-in-Functions.html
   5869   32. https://gcc.gnu.org/wiki/FunctionMultiVersioning
   5870   33. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.1
   5871   34. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.2
   5872   35. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.3
   5873   36. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.4
   5874   37. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.8.5
   5875   38. https://gcc.gnu.org/onlinedocs/
   5876   39. mailto:gcc-help (a] gcc.gnu.org
   5877   40. mailto:gcc (a] gcc.gnu.org
   5878   41. https://gcc.gnu.org/lists.html
   5879   42. https://www.fsf.org/
   5880   43. https://gcc.gnu.org/about.html
   5881   44. http://validator.w3.org/check/referer
   5882 ======================================================================
   5883 http://gcc.gnu.org/gcc-4.7/index.html
   5884                              GCC 4.7 Release Series
   5885 
   5886    (This release series is no longer supported.)
   5887 
   5888    June 12, 2014
   5889 
   5890    The [1]GNU project and the GCC developers are pleased to announce the
   5891    release of GCC 4.7.4.
   5892 
   5893    This release is a bug-fix release, containing fixes for regressions in
   5894    GCC 4.7.3 relative to previous releases of GCC.
   5895 
   5896 Release History
   5897 
   5898    GCC 4.7.4
   5899           June 12, 2014 ([2]changes, [3]documentation)
   5900 
   5901    GCC 4.7.3
   5902           April 11, 2013 ([4]changes, [5]documentation)
   5903 
   5904    GCC 4.7.2
   5905           September 20, 2012 ([6]changes, [7]documentation)
   5906 
   5907    GCC 4.7.1
   5908           June 14, 2012 ([8]changes, [9]documentation)
   5909 
   5910    GCC 4.7.0
   5911           March 22, 2012 ([10]changes, [11]documentation)
   5912 
   5913 References and Acknowledgements
   5914 
   5915    GCC used to stand for the GNU C Compiler, but since the compiler
   5916    supports several other languages aside from C, it now stands for the
   5917    GNU Compiler Collection.
   5918 
   5919    A list of [12]successful builds is updated as new information becomes
   5920    available.
   5921 
   5922    The GCC developers would like to thank the numerous people that have
   5923    contributed new features, improvements, bug fixes, and other changes as
   5924    well as test results to GCC. This [13]amazing group of volunteers is
   5925    what makes GCC successful.
   5926 
   5927    For additional information about GCC please refer to the [14]GCC
   5928    project web site or contact the [15]GCC development mailing list.
   5929 
   5930    To obtain GCC please use [16]our mirror sites or [17]our version
   5931    control system.
   5932 
   5933 
   5934     For questions related to the use of GCC, please consult these web
   5935     pages and the [18]GCC manuals. If that fails, the
   5936     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   5937     web pages and the development of GCC are welcome on our developer
   5938     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   5939     archives.
   5940 
   5941    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   5942    distribution of this entire article is permitted in any medium,
   5943    provided this notice is preserved.
   5944 
   5945    These pages are [23]maintained by the GCC team. Last modified
   5946    2020-01-14[24].
   5947 
   5948 References
   5949 
   5950    1. http://www.gnu.org/
   5951    2. http://gcc.gnu.org/gcc-4.7/changes.html
   5952    3. https://gcc.gnu.org/onlinedocs/4.7.4/
   5953    4. http://gcc.gnu.org/gcc-4.7/changes.html
   5954    5. https://gcc.gnu.org/onlinedocs/4.7.3/
   5955    6. http://gcc.gnu.org/gcc-4.7/changes.html
   5956    7. https://gcc.gnu.org/onlinedocs/4.7.2/
   5957    8. http://gcc.gnu.org/gcc-4.7/changes.html
   5958    9. https://gcc.gnu.org/onlinedocs/4.7.1/
   5959   10. http://gcc.gnu.org/gcc-4.7/changes.html
   5960   11. https://gcc.gnu.org/onlinedocs/4.7.0/
   5961   12. http://gcc.gnu.org/gcc-4.7/buildstat.html
   5962   13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   5963   14. http://gcc.gnu.org/index.html
   5964   15. mailto:gcc (a] gcc.gnu.org
   5965   16. http://gcc.gnu.org/mirrors.html
   5966   17. http://gcc.gnu.org/git.html
   5967   18. https://gcc.gnu.org/onlinedocs/
   5968   19. mailto:gcc-help (a] gcc.gnu.org
   5969   20. mailto:gcc (a] gcc.gnu.org
   5970   21. https://gcc.gnu.org/lists.html
   5971   22. https://www.fsf.org/
   5972   23. https://gcc.gnu.org/about.html
   5973   24. http://validator.w3.org/check/referer
   5974 ======================================================================
   5975 http://gcc.gnu.org/gcc-4.7/changes.html
   5976                              GCC 4.7 Release Series
   5977                         Changes, New Features, and Fixes
   5978 
   5979 Caveats
   5980 
   5981      * The -fconserve-space flag has been deprecated. The flag had no
   5982        effect for most targets: only targets without a global .bss section
   5983        and without support for switchable sections. Furthermore, the flag
   5984        only had an effect for G++, where it could result in wrong
   5985        semantics (please refer to the GCC manual for further details). The
   5986        flag will be removed in GCC 4.8
   5987      * Support for a number of older systems and recently unmaintained or
   5988        untested target ports of GCC has been declared obsolete in GCC 4.7.
   5989        Unless there is activity to revive them, the next release of GCC
   5990        will have their sources permanently removed.
   5991        All GCC ports for the following processor architectures have been
   5992        declared obsolete:
   5993           + picoChip (picochip-*)
   5994        The following ports for individual systems on particular
   5995        architectures have been obsoleted:
   5996           + IRIX 6.5 (mips-sgi-irix6.5)
   5997           + MIPS OpenBSD (mips*-*-openbsd*)
   5998           + Solaris 8 (*-*-solaris2.8). Details can be found in the
   5999             [1]announcement.
   6000           + Tru64 UNIX V5.1 (alpha*-dec-osf5.1*)
   6001      * On ARM, when compiling for ARMv6 (but not ARMv6-M), ARMv7-A,
   6002        ARMv7-R, or ARMv7-M, the new option -munaligned-access is active by
   6003        default, which for some sources generates code that accesses memory
   6004        on unaligned addresses. This requires the kernel of those systems
   6005        to enable such accesses (controlled by CP15 register c1, refer to
   6006        ARM documentation). Alternatively, or for compatibility with
   6007        kernels where unaligned accesses are not supported, all code has to
   6008        be compiled with -mno-unaligned-access. Upstream Linux kernel
   6009        releases have automatically and unconditionally supported unaligned
   6010        accesses as emitted by GCC due to this option being active since
   6011        version 2.6.28.
   6012      * Support on ARM for the legacy floating-point accelerator (FPA) and
   6013        the mixed-endian floating-point format that it used has been
   6014        obsoleted. The ports that still use this format have been obsoleted
   6015        as well. Many legacy ARM ports already provide an alternative that
   6016        uses the VFP floating-point format. The obsolete ports will be
   6017        deleted in the next release.
   6018        The obsolete ports with alternatives are:
   6019           + arm*-*-rtems (use arm*-*-rtemseabi)
   6020           + arm*-*-linux-gnu (use arm*-*-linux-gnueabi)
   6021           + arm*-*-elf (use arm*-*-eabi)
   6022           + arm*-*-uclinux* (use arm*-*-uclinux*eabi)
   6023        Note, however, that these alternatives are not binary compatible
   6024        with their legacy counterparts (although some can support running
   6025        legacy applications).
   6026        The obsolete ports that currently lack a modern alternative are:
   6027           + arm*-*-ecos-elf
   6028           + arm*-*-freebsd
   6029           + arm*-wince-pe*
   6030        New ports that support more recent versions of the architecture are
   6031        welcome.
   6032      * Support for the Maverick co-processor on ARM has been obsoleted.
   6033        Code to support it will be deleted in the next release.
   6034      * Support has been removed for Unix International threads on Solaris
   6035        2, so the --enable-threads=solaris configure option and the
   6036        -threads compiler option don't work any longer.
   6037      * Support has been removed for the Solaris BSD Compatibility Package,
   6038        which lives in /usr/ucbinclude and /usr/ucblib. It has been removed
   6039        from Solaris 11, and was only intended as a migration aid from
   6040        SunOS 4 to SunOS 5. The -compat-bsd compiler option is not
   6041        recognized any longer.
   6042      * The AVR port's libgcc has been improved and its multilib structure
   6043        has been enhanced. As a result, all objects contributing to an
   6044        application must either be compiled with GCC versions up to 4.6.x
   6045        or with GCC versions 4.7.1 or later. If the compiler is used with
   6046        AVR Libc, you need a version that supports the new layout, i.e.
   6047        implements [2]#35407.
   6048      * The AVR port's -mshort-calls command-line option has been
   6049        deprecated. It will be removed in the GCC 4.8 release. See -mrelax
   6050        for a replacement.
   6051      * The AVR port only references startup code that clears .bss and the
   6052        common section resp. initializes the .data and .rodata section
   6053        provided respective sections (or subsections thereof) are not
   6054        empty, see [3]PR18145. Applications that put all static storage
   6055        objects into non-standard sections and / or define all static
   6056        storage objects in assembler modules, must reference __do_clear_bss
   6057        resp. __do_copy_data by hand or undefine the symbol(s) by means of
   6058        -Wl,-u,__do_clear_bss resp. -Wl,-u,__do_copy_data.
   6059      * The ARM port's -mwords-little-endian option has been deprecated. It
   6060        will be removed in a future release.
   6061      * Support has been removed for the NetWare x86 configuration
   6062        obsoleted in GCC 4.6.
   6063      * It is no longer possible to use the "l" constraint in MIPS16 asm
   6064        statements.
   6065      * GCC versions 4.7.0 and 4.7.1 had changes to the C++ standard
   6066        library which affected the ABI in C++11 mode: a data member was
   6067        added to std::list changing its size and altering the definitions
   6068        of some member functions, and std::pair's move constructor was
   6069        non-trivial which altered the calling convention for functions with
   6070        std::pair arguments or return types. The ABI incompatibilities have
   6071        been fixed for GCC version 4.7.2 but as a result C++11 code
   6072        compiled with GCC 4.7.0 or 4.7.1 may be incompatible with C++11
   6073        code compiled with different GCC versions and with C++98/C++03 code
   6074        compiled with any version.
   6075      * On ARM, a bug has been fixed in GCC's implementation of the AAPCS
   6076        rules for the layout of vectors that could lead to wrong code being
   6077        generated. Vectors larger than 8 bytes in size are now by default
   6078        aligned to an 8-byte boundary. This is an ABI change: code that
   6079        makes explicit use of vector types may be incompatible with binary
   6080        objects built with older versions of GCC. Auto-vectorized code is
   6081        not affected by this change. (This change affects GCC versions
   6082        4.7.2 and later.)
   6083      * More information on porting to GCC 4.7 from previous versions of
   6084        GCC can be found in the [4]porting guide for this release.
   6085 
   6086 General Optimizer Improvements
   6087 
   6088      * Support for a new parameter --param case-values-threshold=n was
   6089        added to allow users to control the cutoff between doing switch
   6090        statements as a series of if statements and using a jump table.
   6091      * Link-time optimization (LTO) improvements:
   6092           + Improved scalability and reduced memory usage. Link time
   6093             optimization of Firefox now requires 3GB of RAM on a 64-bit
   6094             system, while over 8GB was needed previously. Linking time has
   6095             been improved, too. The serial stage of linking Firefox has
   6096             been sped up by about a factor of 10.
   6097           + Reduced size of object files and temporary storage used during
   6098             linking.
   6099           + Streaming performance (both outbound and inbound) has been
   6100             improved.
   6101           + ld -r is now supported with LTO.
   6102           + Several bug fixes, especially in symbol table handling and
   6103             merging.
   6104      * Interprocedural optimization improvements:
   6105           + Heuristics now take into account that after inlining code will
   6106             be optimized out because of known values (or properties) of
   6107             function parameters. For example:
   6108 void foo(int a)
   6109 {
   6110   if (a > 10)
   6111     ... huge code ...
   6112 }
   6113 void bar (void)
   6114 {
   6115   foo (0);
   6116 }
   6117 
   6118             The call of foo will be inlined into bar even when optimizing
   6119             for code size. Constructs based on __builtin_constant_p are
   6120             now understood by the inliner and code size estimates are
   6121             evaluated a lot more realistically.
   6122           + The representation of C++ virtual thunks and aliases (both
   6123             implicit and defined via the alias attribute) has been
   6124             re-engineered. Aliases no longer pose optimization barriers
   6125             and calls to an alias can be inlined and otherwise optimized.
   6126           + The inter-procedural constant propagation pass has been
   6127             rewritten. It now performs generic function specialization.
   6128             For example when compiling the following:
   6129 void foo(bool flag)
   6130 {
   6131   if (flag)
   6132     ... do something ...
   6133   else
   6134     ... do something else ...
   6135 }
   6136 void bar (void)
   6137 {
   6138   foo (false);
   6139   foo (true);
   6140   foo (false);
   6141   foo (true);
   6142   foo (false);
   6143   foo (true);
   6144 }
   6145 
   6146             GCC will now produce two copies of foo. One with flag being
   6147             true, while other with flag being false. This leads to
   6148             performance improvements previously possible only by inlining
   6149             all calls. Cloning causes a lot less code size growth.
   6150      * A string length optimization pass has been added. It attempts to
   6151        track string lengths and optimize various standard C string
   6152        functions like strlen, strchr, strcpy, strcat, stpcpy and their
   6153        _FORTIFY_SOURCE counterparts into faster alternatives. This pass is
   6154        enabled by default at -O2 or above, unless optimizing for size, and
   6155        can be disabled by the -fno-optimize-strlen option. The pass can
   6156        e.g. optimize
   6157 char *bar (const char *a)
   6158 {
   6159   size_t l = strlen (a) + 2;
   6160   char *p = malloc (l); if (p == NULL) return p;
   6161   strcpy (p, a); strcat (p, "/"); return p;
   6162 }
   6163 
   6164        into:
   6165 char *bar (const char *a)
   6166 {
   6167   size_t tmp = strlen (a);
   6168   char *p = malloc (tmp + 2); if (p == NULL) return p;
   6169   memcpy (p, a, tmp); memcpy (p + tmp, "/", 2); return p;
   6170 }
   6171 
   6172        or for hosted compilations where stpcpy is available in the runtime
   6173        and headers provide its prototype, e.g.
   6174 void foo (char *a, const char *b, const char *c, const char *d)
   6175 {
   6176   strcpy (a, b); strcat (a, c); strcat (a, d);
   6177 }
   6178 
   6179        can be optimized into:
   6180 void foo (char *a, const char *b, const char *c, const char *d)
   6181 {
   6182   strcpy (stpcpy (stpcpy (a, b), c), d);
   6183 }
   6184 
   6185 New Languages and Language specific improvements
   6186 
   6187      * Version 3.1 of the OpenMP specification is now supported for the C,
   6188        C++, and Fortran compilers.
   6189 
   6190   Ada
   6191 
   6192      * The command-line option -feliminate-unused-debug-types has been
   6193        re-enabled by default, as it is for the other languages, leading to
   6194        a reduction in debug info size of 12.5% and more for relevant
   6195        cases, as well as to a small compilation speedup.
   6196 
   6197   C family
   6198 
   6199      * A new built-in, __builtin_assume_aligned, has been added, through
   6200        which the compiler can be hinted about pointer alignment and can
   6201        use it to improve generated code.
   6202      * A new warning option -Wunused-local-typedefs was added for C, C++,
   6203        Objective-C and Objective-C++. This warning diagnoses typedefs
   6204        locally defined in a function, and otherwise not used.
   6205      * A new experimental command-line option -ftrack-macro-expansion was
   6206        added for C, C++, Objective-C, Objective-C++ and Fortran. It allows
   6207        the compiler to emit diagnostic about the current macro expansion
   6208        stack when a compilation error occurs in a macro expansion.
   6209      * Experimental support for transactional memory has been added. It
   6210        includes support in the compiler, as well as a supporting runtime
   6211        library called libitm. To compile code with transactional memory
   6212        constructs, use the -fgnu-tm option.
   6213        Support is currently available for Alpha, ARM, PowerPC, SH, SPARC,
   6214        and 32-bit/64-bit x86 platforms.
   6215        For more details on transactional memory see [5]the GCC WiKi.
   6216      * Support for atomic operations specifying the C++11/C11 memory model
   6217        has been added. These new __atomic routines replace the existing
   6218        __sync built-in routines.
   6219        Atomic support is also available for memory blocks. Lock-free
   6220        instructions will be used if a memory block is the same size and
   6221        alignment as a supported integer type. Atomic operations which do
   6222        not have lock-free support are left as function calls. A set of
   6223        library functions is available on the GCC atomic wiki in the
   6224        "External Atomics Library" section.
   6225        For more details on the memory models and features, see the
   6226        [6]atomic wiki.
   6227      * When a binary operation is performed on vector types and one of the
   6228        operands is a uniform vector, it is possible to replace the vector
   6229        with the generating element. For example:
   6230 typedef int v4si __attribute__ ((vector_size (16)));
   6231 v4si res, a = {1,2,3,4};
   6232 int x;
   6233 
   6234 res = 2 + a;  /* means {2,2,2,2} + a  */
   6235 res = a - x;  /* means a - {x,x,x,x}  */
   6236 
   6237   C
   6238 
   6239      * There is support for some more features from the C11 revision of
   6240        the ISO C standard. GCC now accepts the options -std=c11 and
   6241        -std=gnu11, in addition to the previous -std=c1x and -std=gnu1x.
   6242           + Unicode strings (previously supported only with options such
   6243             as -std=gnu11, now supported with -std=c11), and the
   6244             predefined macros __STDC_UTF_16__ and __STDC_UTF_32__.
   6245           + Nonreturning functions (_Noreturn and <stdnoreturn.h>).
   6246           + Alignment support (_Alignas, _Alignof, max_align_t,
   6247             <stdalign.h>).
   6248           + A built-in function __builtin_complex is provided to support C
   6249             library implementation of the CMPLX family of macros.
   6250 
   6251   C++
   6252 
   6253      * G++ now accepts the -std=c++11, -std=gnu++11, and -Wc++11-compat
   6254        options, which are equivalent to -std=c++0x, -std=gnu++0x, and
   6255        -Wc++0x-compat, respectively.
   6256      * G++ now implements [7]C++11 extended friend syntax:
   6257 
   6258 template<class W>
   6259 class Q
   6260 {
   6261   static const int I = 2;
   6262 public:
   6263   friend W;
   6264 };
   6265 
   6266 struct B
   6267 {
   6268   int ar[Q<B>::I];
   6269 };
   6270 
   6271      * Thanks to Ville Voutilainen, G++ now implements [8]C++11 explicit
   6272        override control.
   6273 
   6274 struct B {
   6275   virtual void f() const final;
   6276   virtual void f(int);
   6277 };
   6278 
   6279 struct D : B {
   6280   void f() const;            // error: D::f attempts to override final B::f
   6281   void f(long) override;     // error: doesn't override anything
   6282   void f(int) override;      // ok
   6283 };
   6284 
   6285 struct E final { };
   6286 struct F: E { }; // error: deriving from final class
   6287 
   6288      * G++ now implements [9]C++11 non-static data member initializers.
   6289 
   6290 struct A {
   6291   int i = 42;
   6292 } a; // initializes a.i to 42
   6293 
   6294      * Thanks to Ed Smith-Rowland, G++ now implements [10]C++11
   6295        user-defined literals.
   6296 
   6297 // Not actually a good approximation.  :)
   6298 constexpr long double operator"" _degrees (long double d) { return d * 0.0175; }
   6299 long double pi = 180.0_degrees;
   6300 
   6301      * G++ now implements [11]C++11 alias-declarations.
   6302 
   6303 template <class T> using Ptr = T*;
   6304 Ptr<int> ip;  // decltype(ip) is int*
   6305 
   6306      * Thanks to Ville Voutilainen and Pedro Lamaro, G++ now implements
   6307        [12]C++11 delegating constructors.
   6308 
   6309 struct A {
   6310   A(int);
   6311   A(): A(42) { } // delegate to the A(int) constructor
   6312 };
   6313 
   6314      * G++ now fully implements C++11 atomic classes rather than just
   6315        integer derived classes.
   6316 
   6317 class POD {
   6318   int a;
   6319   int b;
   6320 };
   6321 std::atomic<POD> my_atomic_POD;
   6322 
   6323      * G++ now sets the predefined macro __cplusplus to the correct value,
   6324        199711L for C++98/03, and 201103L for C++11.
   6325      * G++ now correctly implements the two-phase lookup rules such that
   6326        an unqualified name used in a template must have an appropriate
   6327        declaration found either in scope at the point of definition of the
   6328        template or by argument-dependent lookup at the point of
   6329        instantiation. As a result, code that relies on a second
   6330        unqualified lookup at the point of instantiation to find functions
   6331        declared after the template or in dependent bases will be rejected.
   6332        The compiler will suggest ways to fix affected code, and using the
   6333        -fpermissive compiler flag will allow the code to compile with a
   6334        warning.
   6335 
   6336 template <class T>
   6337 void f() { g(T()); } // error, g(int) not found by argument-dependent lookup
   6338 void g(int) { } // fix by moving this declaration before the declaration of f
   6339 
   6340 template <class T>
   6341 struct A: T {
   6342   // error, B::g(B) not found by argument-dependent lookup
   6343   void f() { g(T()); } // fix by using this->g or A::g
   6344 };
   6345 
   6346 struct B { void g(B); };
   6347 
   6348 int main()
   6349 {
   6350   f<int>();
   6351   A<B>().f();
   6352 }
   6353 
   6354      * G++ now properly re-uses stack space allocated for temporary
   6355        objects when their lifetime ends, which can significantly lower
   6356        stack consumption for some C++ functions. As a result of this, some
   6357        code with undefined behavior will now break:
   6358 
   6359 const int &f(const int &i) { return i; }
   6360 ....
   6361 const int &x = f(1);
   6362 const int &y = f(2);
   6363 
   6364        Here, x refers to the temporary allocated to hold the 1 argument,
   6365        which only lives until the end of the initialization; it
   6366        immediately becomes a dangling reference. So the next statement
   6367        re-uses the stack slot to hold the 2 argument, and users of x get
   6368        that value instead.
   6369        Note that this should not cause any change of behavior for
   6370        temporaries of types with non-trivial destructors, as they are
   6371        already destroyed at end of full-expression; the change is that now
   6372        the storage is released as well.
   6373      * A new command-line option -Wdelete-non-virtual-dtor has been added
   6374        to warn when delete is used to destroy an instance of a class which
   6375        has virtual functions and non-virtual destructor. It is unsafe to
   6376        delete an instance of a derived class through a pointer to a base
   6377        class if the base class does not have a virtual destructor. This
   6378        warning is enabled by -Wall.
   6379      * A new command-line option -Wzero-as-null-pointer-constant has been
   6380        added to warn when a literal '0' is used as null pointer constant.
   6381        It can be useful to facilitate the conversion to nullptr in C++11.
   6382      * As per C++98, access-declarations are now deprecated by G++.
   6383        Using-declarations are to be used instead. Furthermore, some
   6384        efforts have been made to improve the support of class scope
   6385        using-declarations. In particular, using-declarations referring to
   6386        a dependent type now work as expected ([13]bug c++/14258).
   6387      * The ELF symbol visibility of a template instantiation is now
   6388        properly constrained by the visibility of its template arguments
   6389        ([14]bug c++/35688).
   6390 
   6391     Runtime Library (libstdc++)
   6392 
   6393      * [15]Improved experimental support for the new ISO C++ standard,
   6394        C++11, including:
   6395           + using noexcept in most of the library;
   6396           + implementations of pointer_traits, allocator_traits and
   6397             scoped_allocator_adaptor;
   6398           + uses-allocator construction for tuple;
   6399           + vector meets the allocator-aware container requirements;
   6400           + replacing monotonic_clock with steady_clock;
   6401           + enabling the thread support library on most POSIX targets;
   6402           + many small improvements to conform to the FDIS.
   6403      * Added --enable-clocale=newlib configure option.
   6404      * Debug Mode iterators for unordered associative containers.
   6405      * Avoid polluting the global namespace and do not include <unistd.h>.
   6406 
   6407   Fortran
   6408 
   6409      * The compile flag [16]-fstack-arrays has been added, which causes
   6410        all local arrays to be put on stack memory. For some programs this
   6411        will improve the performance significantly. If your program uses
   6412        very large local arrays, it is possible that you will have to
   6413        extend your runtime limits for stack memory.
   6414      * The [17]-Ofast flag now also implies [18]-fno-protect-parens and
   6415        [19]-fstack-arrays.
   6416      * Front-end optimizations can now be selected by the
   6417        [20]-ffrontend-optimize option and deselected by the
   6418        -fno-frontend-optimize option.
   6419      * When front-end optimization removes a function call,
   6420        [21]-Wfunction-elimination warns about that.
   6421      * When performing front-end-optimization, the
   6422        [22]-faggressive-function-elimination option allows the removal of
   6423        duplicate function calls even for impure functions.
   6424      * The flag [23]-Wreal-q-constant has been added, which warns if
   6425        floating-point literals have been specified using q (such as
   6426        1.0q0); the q marker is now supported as a vendor extension to
   6427        denote quad precision (REAL(16) or, if not available, REAL(10)).
   6428        Consider using a kind parameter (such as in 1.0_qp) instead, which
   6429        can be obtained via [24]SELECTED_REAL_KIND.
   6430      * The GFORTRAN_USE_STDERR environment variable has been removed. GNU
   6431        Fortran now always prints error messages to standard error. If you
   6432        wish to redirect standard error, please consult the manual for your
   6433        OS, shell, batch environment etc. as appropriate.
   6434      * The -fdump-core option and GFORTRAN_ERROR_DUMPCORE environment
   6435        variable have been removed. When encountering a serious error,
   6436        gfortran will now always abort the program. Whether a core dump is
   6437        generated depends on the user environment settings; see the ulimit
   6438        -c setting for POSIX shells, limit coredumpsize for C shells, and
   6439        the [25]WER user-mode dumps settings on Windows.
   6440      * The [26]-fbacktrace option is now enabled by default. When
   6441        encountering a fatal error, gfortran will attempt to print a
   6442        backtrace to standard error before aborting. It can be disabled
   6443        with -fno-backtrace. Note: On POSIX targets with the addr2line
   6444        utility from GNU binutils, GNU Fortran can print a backtrace with
   6445        function name, file name, line number information in addition to
   6446        the addresses; otherwise only the addresses are printed.
   6447      * [27]Fortran 2003:
   6448           + Generic interface names which have the same name as derived
   6449             types are now supported, which allows to write constructor
   6450             functions. Note that Fortran does not support static
   6451             constructor functions; only default initialization or an
   6452             explicit structure-constructor initialization are available.
   6453           + [28]Polymorphic (class) arrays are now supported.
   6454      * [29]Fortran 2008:
   6455           + Support for the DO CONCURRENT construct has been added, which
   6456             allows the user to specify that individual loop iterations
   6457             have no interdependencies.
   6458           + [30]Coarrays: Full single-image support except for polymorphic
   6459             coarrays. Additionally, preliminary support for multiple
   6460             images via an MPI-based [31]coarray communication library has
   6461             been added. Note: The library version is not yet usable as
   6462             remote coarray access is not yet possible.
   6463      * [32]TS 29113:
   6464           + New flag [33]-std=f2008ts permits programs that are expected
   6465             to conform to the Fortran 2008 standard and the draft
   6466             Technical Specification (TS) 29113 on Further Interoperability
   6467             of Fortran with C.
   6468           + The OPTIONAL attribute is now allowed for dummy arguments of
   6469             BIND(C) procedures.
   6470           + The RANK intrinsic has been added.
   6471           + The implementation of the ASYNCHRONOUS attribute in GCC is
   6472             compatible with the candidate draft of TS 29113 (since GCC
   6473             4.6).
   6474 
   6475   Go
   6476 
   6477      * GCC 4.7 implements the [34]Go 1 language standard. The library
   6478        support in 4.7.0 is not quite complete, due to release timing.
   6479        Release 4.7.1 includes complete support for Go 1. The Go library is
   6480        from the Go 1.0.1 release.
   6481      * Go has been tested on GNU/Linux and Solaris platforms. It may work
   6482        on other platforms as well.
   6483 
   6484 New Targets and Target Specific Improvements
   6485 
   6486   ARM
   6487 
   6488      * GCC now supports the Cortex-A7 processor implementing the v7-a
   6489        version of the architecture using the option -mcpu=cortex-a7.
   6490      * The default vector size in auto-vectorization for NEON is now 128
   6491        bits. If vectorization fails thusly, the vectorizer tries again
   6492        with 64-bit vectors.
   6493      * A new option -mvectorize-with-neon-double was added to allow users
   6494        to change the vector size to 64 bits.
   6495 
   6496   AVR
   6497 
   6498      * GCC now supports the XMEGA architecture. This requires GNU binutils
   6499        2.22 or later.
   6500      * Support for the [35]named address spaces __flash, __flash1, ,
   6501        __flash5 and __memx has been added. These address spaces locate
   6502        read-only data in flash memory and allow reading from flash memory
   6503        by means of ordinary C code, i.e. without the need of (inline)
   6504        assembler code:
   6505 
   6506 const __flash int values[] = { 42, 31 };
   6507 
   6508 int add_values (const __flash int *p, int i)
   6509 {
   6510     return values[i] + *p;
   6511 }
   6512 
   6513      * Support has been added for the AVR-specific configure option
   6514        --with-avrlibc=yes in order to arrange for better integration of
   6515        [36]AVR-Libc. This configure option is supported in avr-gcc 4.7.2
   6516        and newer and will only take effect in non-RTEMS configurations. If
   6517        avr-gcc is configured for RTEMS, the option will be ignored which
   6518        is the same as specifying --with-avrlibc=no. See [37]PR54461 for
   6519        more technical details.
   6520      * Support for AVR-specific [38]built-in functions has been added.
   6521      * Support has been added for the signed and unsigned 24-bit scalar
   6522        integer types __int24 and __uint24.
   6523      * New command-line options -maccumulate-args, -mbranch-cost=cost and
   6524        -mstrict-X were added to allow better fine-tuning of code
   6525        optimization.
   6526      * The command-line option -fdata-sections now also takes affect on
   6527        the section names of variables with the progmem attribute.
   6528      * A new inline assembler print modifier %i to print a RAM address as
   6529        I/O address has been added:
   6530 
   6531 #include <avr/io.h> /* Port Definitions from AVR-LibC */
   6532 
   6533 void set_portb (uint8_t value)
   6534 {
   6535     asm volatile ("out %i0, %1" :: "n" (&PORTB), "r" (value) : "memory");
   6536 }
   6537 
   6538        The offset between an I/O address and the RAM address for that I/O
   6539        location is device-specific. This offset is taken into account when
   6540        printing a RAM address with the %i modifier so that the address is
   6541        suitable to be used as operand in an I/O command. The address must
   6542        be a constant integer known at compile time.
   6543      * The inline assembler constraint "R" to represent integers in the
   6544        range 6  5 has been removed without replacement.
   6545      * Many optimizations to:
   6546           + 64-bit integer arithmetic
   6547           + Widening multiplication
   6548           + Integer division by a constant
   6549           + Avoid constant reloading in multi-byte instructions.
   6550           + Micro-optimizations for special instruction sequences.
   6551           + Generic built-in functions like __builtin_ffs*,
   6552             __builtin_clz*, etc.
   6553           + If-else decision trees generated by switch instructions
   6554           + Merging of data located in flash memory
   6555           + New libgcc variants for devices with 8-bit wide stack pointer
   6556           + 
   6557      * Better documentation:
   6558           + Handling of EIND and indirect jumps on devices with more than
   6559             128 KiB of program memory.
   6560           + Handling of the RAMPD, RAMPX, RAMPY and RAMPZ special function
   6561             registers.
   6562           + Function attributes OS_main and OS_task.
   6563           + AVR-specific built-in macros.
   6564 
   6565   C6X
   6566 
   6567      * Support has been added for the Texas Instruments C6X family of
   6568        processors.
   6569 
   6570   CR16
   6571 
   6572      * Support has been added for National Semiconductor's CR16
   6573        architecture.
   6574 
   6575   Epiphany
   6576 
   6577      * Support has been added for Adapteva's Epiphany architecture.
   6578 
   6579   IA-32/x86-64
   6580 
   6581      * Support for Intel AVX2 intrinsics, built-in functions and code
   6582        generation is available via -mavx2.
   6583      * Support for Intel BMI2 intrinsics, built-in functions and code
   6584        generation is available via -mbmi2.
   6585      * Implementation and automatic generation of __builtin_clz* using the
   6586        lzcnt instruction is available via -mlzcnt.
   6587      * Support for Intel FMA3 intrinsics and code generation is available
   6588        via -mfma.
   6589      * A new -mfsgsbase command-line option is available that makes GCC
   6590        generate new segment register read/write instructions through
   6591        dedicated built-ins.
   6592      * Support for the new Intel rdrnd instruction is available via
   6593        -mrdrnd.
   6594      * Two additional AVX vector conversion instructions are available via
   6595        -mf16c.
   6596      * Support for new Intel processor codename IvyBridge with RDRND,
   6597        FSGSBASE and F16C is available through -march=core-avx-i.
   6598      * Support for the new Intel processor codename Haswell with AVX2,
   6599        FMA, BMI, BMI2, LZCNT is available through -march=core-avx2.
   6600      * Support for new AMD family 15h processors (Piledriver core) is now
   6601        available through -march=bdver2 and -mtune=bdver2 options.
   6602      * Support for [39]the x32 psABI is now available through the -mx32
   6603        option.
   6604      * Windows mingw targets are using the -mms-bitfields option by
   6605        default.
   6606      * Windows x86 targets are using the __thiscall calling convention for
   6607        C++ class-member functions.
   6608      * Support for the configure option --with-threads=posix for Windows
   6609        mingw targets.
   6610 
   6611   MIPS
   6612 
   6613      * GCC now supports thread-local storage (TLS) for MIPS16. This
   6614        requires GNU binutils 2.22 or later.
   6615      * GCC can now generate code specifically for the Cavium Octeon+ and
   6616        Octeon2 processors. The associated command-line options are
   6617        -march=octeon+ and -march=octeon2 respectively. Both options
   6618        require GNU binutils 2.22 or later.
   6619      * GCC can now work around certain 24k errata, under the control of
   6620        the command-line option -mfix-24k. These workarounds require GNU
   6621        binutils 2.20 or later.
   6622      * 32-bit MIPS GNU/Linux targets such as mips-linux-gnu can now build
   6623        n32 and n64 multilibs. The result is effectively a 64-bit GNU/Linux
   6624        toolchain that generates 32-bit code by default. Use the
   6625        configure-time option --enable-targets=all to select these extra
   6626        multilibs.
   6627      * Passing -fno-delayed-branch now also stops the assembler from
   6628        automatically filling delay slots.
   6629 
   6630   PowerPC/PowerPC64
   6631 
   6632      * Vectors of type vector long long or vector long are passed and
   6633        returned using the same method as other vectors with the VSX
   6634        instruction set. Previously GCC did not adhere to the ABI for
   6635        128-bit vectors with 64-bit integer base types (PR 48857). This
   6636        will also be fixed in the GCC 4.6.1 and 4.5.4 releases.
   6637      * A new option -mno-pointers-to-nested-functions was added to allow
   6638        AIX 32-bit/64-bit and GNU/Linux 64-bit PowerPC users to specify
   6639        that the compiler should not load up the chain register (r11)
   6640        before calling a function through a pointer. If you use this
   6641        option, you cannot call nested functions through a pointer, or call
   6642        other languages that might use the static chain.
   6643      * A new option msave-toc-indirect was added to allow AIX
   6644        32-bit/64-bit and GNU/Linux 64-bit PowerPC users control whether we
   6645        save the TOC in the prologue for indirect calls or generate the
   6646        save inline. This can speed up some programs that call through a
   6647        function pointer a lot, but it can slow down other functions that
   6648        only call through a function pointer in exceptional cases.
   6649      * The PowerPC port will now enable machine-specific built-in
   6650        functions when the user switches the target machine using the
   6651        #pragma GCC target or __attribute__ ((__target__ ("target"))) code
   6652        sequences. In addition, the target macros are updated. However, due
   6653        to the way the -save-temps switch is implemented, you won't see the
   6654        effect of these additional macros being defined in preprocessor
   6655        output.
   6656 
   6657   SH
   6658 
   6659      * A new option -msoft-atomic has been added. When it is specified,
   6660        GCC will generate GNU/Linux-compatible gUSA atomic sequences for
   6661        the new __atomic routines.
   6662      * Since it is neither supported by GAS nor officially documented,
   6663        code generation for little endian SH2A has been disabled.
   6664        Specifying -ml with -m2a* will now result in a compiler error.
   6665      * The defunct -mbranch-cost option has been fixed.
   6666      * Some improvements to the generated code of:
   6667           + Utilization of the tst #imm,R0 instruction.
   6668           + Dynamic shift instructions on SH2A.
   6669           + Integer absolute value calculations.
   6670      * The -mdiv= option for targets other than SHmedia has been fixed and
   6671        documented.
   6672 
   6673   SPARC
   6674 
   6675      * The option -mflat has been reinstated. When it is specified, the
   6676        compiler will generate code for a single register window model.
   6677        This is essentially a new implementation and the corresponding
   6678        debugger support has been added to GDB 7.4.
   6679      * Support for the options -mtune=native and -mcpu=native has been
   6680        added on selected native platforms (GNU/Linux and Solaris).
   6681      * Support for the SPARC T3 (Niagara 3) processor has been added.
   6682      * VIS:
   6683           + An intrinsics header visintrin.h has been added.
   6684           + Builtin intrinsics for the VIS 1.0 edge handling and pixel
   6685             compare instructions have been added.
   6686           + The little-endian version of alignaddr is now supported.
   6687           + When possible, VIS builtins are marked const, which should
   6688             increase the compiler's ability to optimize VIS operations.
   6689           + The compiler now properly tracks the %gsr register and how it
   6690             behaves as an input for various VIS instructions.
   6691           + Akin to fzero, the compiler can now generate fone instructions
   6692             in order to set all of the bits of a floating-point register
   6693             to 1.
   6694           + The documentation for the VIS intrinsics in the GCC manual has
   6695             been brought up to date and many inaccuracies were fixed.
   6696           + Intrinsics for the VIS 2.0 bmask, bshuffle, and
   6697             non-condition-code setting edge instructions have been added.
   6698             Their availability is controlled by the new -mvis2 and
   6699             -mno-vis2 options. They are enabled by default on
   6700             UltraSPARC-III and later CPUs.
   6701      * Support for UltraSPARC Fused Multiply-Add floating-point extensions
   6702        has been added. These instructions are enabled by default on SPARC
   6703        T3 (Niagara 3) and later CPUs.
   6704 
   6705   TILE-Gx/TILEPro
   6706 
   6707      * Support has been added for the Tilera TILE-Gx and TILEPro families
   6708        of processors.
   6709 
   6710 Other significant improvements
   6711 
   6712      * A new option (-grecord-gcc-switches) was added that appends
   6713        compiler command-line options that might affect code generation to
   6714        the DW_AT_producer attribute string in the DWARF debugging
   6715        information.
   6716      * GCC now supports various new GNU extensions to the DWARF debugging
   6717        information format, like [40]entry value and [41]call site
   6718        information, [42]typed DWARF stack or [43]a more compact macro
   6719        representation. Support for these extensions has been added to GDB
   6720        7.4. They can be disabled through the -gstrict-dwarf command-line
   6721        option.
   6722 
   6723 GCC 4.7.1
   6724 
   6725    This is the [44]list of problem reports (PRs) from GCC's bug tracking
   6726    system that are known to be fixed in the 4.7.1 release. This list might
   6727    not be complete (that is, it is possible that some PRs that have been
   6728    fixed are not listed here).
   6729 
   6730    The Go front end in the 4.7.1 release fully supports the [45]Go 1
   6731    language standard.
   6732 
   6733 GCC 4.7.2
   6734 
   6735    This is the [46]list of problem reports (PRs) from GCC's bug tracking
   6736    system that are known to be fixed in the 4.7.2 release. This list might
   6737    not be complete (that is, it is possible that some PRs that have been
   6738    fixed are not listed here).
   6739 
   6740 GCC 4.7.3
   6741 
   6742    This is the [47]list of problem reports (PRs) from GCC's bug tracking
   6743    system that are known to be fixed in the 4.7.3 release. This list might
   6744    not be complete (that is, it is possible that some PRs that have been
   6745    fixed are not listed here).
   6746 
   6747 GCC 4.7.4
   6748 
   6749    This is the [48]list of problem reports (PRs) from GCC's bug tracking
   6750    system that are known to be fixed in the 4.7.4 release. This list might
   6751    not be complete (that is, it is possible that some PRs that have been
   6752    fixed are not listed here).
   6753 
   6754 
   6755     For questions related to the use of GCC, please consult these web
   6756     pages and the [49]GCC manuals. If that fails, the
   6757     [50]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   6758     web pages and the development of GCC are welcome on our developer
   6759     list at [51]gcc (a] gcc.gnu.org. All of [52]our lists have public
   6760     archives.
   6761 
   6762    Copyright (C) [53]Free Software Foundation, Inc. Verbatim copying and
   6763    distribution of this entire article is permitted in any medium,
   6764    provided this notice is preserved.
   6765 
   6766    These pages are [54]maintained by the GCC team. Last modified
   6767    2019-11-28[55].
   6768 
   6769 References
   6770 
   6771    1. https://gcc.gnu.org/ml/gcc-patches/2011-03/msg01263.html
   6772    2. http://savannah.nongnu.org/bugs/?35407
   6773    3. https://gcc.gnu.org/PR18145
   6774    4. https://gcc.gnu.org/gcc-4.7/porting_to.html
   6775    5. https://gcc.gnu.org/wiki/TransactionalMemory
   6776    6. https://gcc.gnu.org/wiki/Atomic/GCCMM
   6777    7. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6778    8. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6779    9. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6780   10. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6781   11. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6782   12. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   6783   13. https://gcc.gnu.org/PR14258
   6784   14. https://gcc.gnu.org/PR35688
   6785   15. https://gcc.gnu.org/onlinedocs/gcc-4.7.4/libstdc++/manual/manual/status.html#status.iso.2011
   6786   16. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254
   6787   17. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Optimize-Options.html#index-Ofast-689
   6788   18. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfno-protect-parens_007d-270
   6789   19. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254
   6790   20. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfrontend-optimize_007d-275
   6791   21. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWfunction-elimination_007d-170
   6792   22. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfaggressive-function-elimination_007d-270
   6793   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
   6794   24. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/SELECTED_005fREAL_005fKIND.html
   6795   25. https://docs.microsoft.com/en-us/windows/win32/wer/collecting-user-mode-dumps
   6796   26. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gfortran/Debugging-Options.html#index-g_t_0040code_007bfno-backtrace_007d-183
   6797   27. https://gcc.gnu.org/wiki/Fortran2003Status
   6798   28. https://gcc.gnu.org/wiki/OOP
   6799   29. https://gcc.gnu.org/wiki/Fortran2008Status
   6800   30. https://gcc.gnu.org/wiki/Coarray
   6801   31. https://gcc.gnu.org/wiki/CoarrayLib
   6802   32. https://gcc.gnu.org/wiki/TS29113Status
   6803   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
   6804   34. https://golang.org/doc/go1
   6805   35. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/Named-Address-Spaces.html
   6806   36. http://nongnu.org/avr-libc/
   6807   37. https://gcc.gnu.org/PR54461
   6808   38. https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/AVR-Built_002din-Functions.html
   6809   39. https://sites.google.com/site/x32abi/
   6810   40. http://www.dwarfstd.org/ShowIssue.php?issue=100909.1
   6811   41. http://www.dwarfstd.org/ShowIssue.php?issue=100909.2
   6812   42. http://www.dwarfstd.org/ShowIssue.php?issue=140425.1
   6813   43. http://www.dwarfstd.org/ShowIssue.php?issue=110722.1
   6814   44. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.1
   6815   45. https://golang.org/doc/go1
   6816   46. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.2
   6817   47. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.3
   6818   48. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.4
   6819   49. https://gcc.gnu.org/onlinedocs/
   6820   50. mailto:gcc-help (a] gcc.gnu.org
   6821   51. mailto:gcc (a] gcc.gnu.org
   6822   52. https://gcc.gnu.org/lists.html
   6823   53. https://www.fsf.org/
   6824   54. https://gcc.gnu.org/about.html
   6825   55. http://validator.w3.org/check/referer
   6826 ======================================================================
   6827 http://gcc.gnu.org/gcc-4.6/index.html
   6828                              GCC 4.6 Release Series
   6829 
   6830    (This release series is no longer supported.)
   6831 
   6832    April 12, 2013
   6833 
   6834    The [1]GNU project and the GCC developers are pleased to announce the
   6835    release of GCC 4.6.4.
   6836 
   6837    This release is a bug-fix release, containing fixes for regressions in
   6838    GCC 4.6.3 relative to previous releases of GCC.
   6839 
   6840 Release History
   6841 
   6842    GCC 4.6.4
   6843           April 12, 2013 ([2]changes, [3]documentation)
   6844 
   6845    GCC 4.6.3
   6846           March 1, 2012 ([4]changes, [5]documentation)
   6847 
   6848    GCC 4.6.2
   6849           October 26, 2011 ([6]changes, [7]documentation)
   6850 
   6851    GCC 4.6.1
   6852           June 27, 2011 ([8]changes, [9]documentation)
   6853 
   6854    GCC 4.6.0
   6855           March 25, 2011 ([10]changes, [11]documentation)
   6856 
   6857 References and Acknowledgements
   6858 
   6859    GCC used to stand for the GNU C Compiler, but since the compiler
   6860    supports several other languages aside from C, it now stands for the
   6861    GNU Compiler Collection.
   6862 
   6863    A list of [12]successful builds is updated as new information becomes
   6864    available.
   6865 
   6866    The GCC developers would like to thank the numerous people that have
   6867    contributed new features, improvements, bug fixes, and other changes as
   6868    well as test results to GCC. This [13]amazing group of volunteers is
   6869    what makes GCC successful.
   6870 
   6871    For additional information about GCC please refer to the [14]GCC
   6872    project web site or contact the [15]GCC development mailing list.
   6873 
   6874    To obtain GCC please use [16]our mirror sites or [17]our version
   6875    control system.
   6876 
   6877 
   6878     For questions related to the use of GCC, please consult these web
   6879     pages and the [18]GCC manuals. If that fails, the
   6880     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   6881     web pages and the development of GCC are welcome on our developer
   6882     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   6883     archives.
   6884 
   6885    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   6886    distribution of this entire article is permitted in any medium,
   6887    provided this notice is preserved.
   6888 
   6889    These pages are [23]maintained by the GCC team. Last modified
   6890    2020-01-14[24].
   6891 
   6892 References
   6893 
   6894    1. http://www.gnu.org/
   6895    2. http://gcc.gnu.org/gcc-4.6/changes.html
   6896    3. https://gcc.gnu.org/onlinedocs/4.6.4/
   6897    4. http://gcc.gnu.org/gcc-4.6/changes.html
   6898    5. https://gcc.gnu.org/onlinedocs/4.6.3/
   6899    6. http://gcc.gnu.org/gcc-4.6/changes.html
   6900    7. https://gcc.gnu.org/onlinedocs/4.6.2/
   6901    8. http://gcc.gnu.org/gcc-4.6/changes.html
   6902    9. https://gcc.gnu.org/onlinedocs/4.6.1/
   6903   10. http://gcc.gnu.org/gcc-4.6/changes.html
   6904   11. https://gcc.gnu.org/onlinedocs/4.6.0/
   6905   12. http://gcc.gnu.org/gcc-4.6/buildstat.html
   6906   13. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   6907   14. http://gcc.gnu.org/index.html
   6908   15. mailto:gcc (a] gcc.gnu.org
   6909   16. http://gcc.gnu.org/mirrors.html
   6910   17. http://gcc.gnu.org/git.html
   6911   18. https://gcc.gnu.org/onlinedocs/
   6912   19. mailto:gcc-help (a] gcc.gnu.org
   6913   20. mailto:gcc (a] gcc.gnu.org
   6914   21. https://gcc.gnu.org/lists.html
   6915   22. https://www.fsf.org/
   6916   23. https://gcc.gnu.org/about.html
   6917   24. http://validator.w3.org/check/referer
   6918 ======================================================================
   6919 http://gcc.gnu.org/gcc-4.6/changes.html
   6920                              GCC 4.6 Release Series
   6921                         Changes, New Features, and Fixes
   6922 
   6923 Caveats
   6924 
   6925      * The options -b <machine> and -V <version> have been removed because
   6926        they were unreliable. Instead, users should directly run
   6927        <machine>-gcc when cross-compiling, or <machine>-gcc-<version> to
   6928        run a different version of gcc.
   6929      * GCC now has stricter checks for invalid command-line options. In
   6930        particular, when gcc was called to link object files rather than
   6931        compile source code, it would previously accept and ignore all
   6932        options starting with --, including linker options such as
   6933        --as-needed and --export-dynamic, although such options would
   6934        result in errors if any source code was compiled. Such options, if
   6935        unknown to the compiler, are now rejected in all cases; if the
   6936        intent was to pass them to the linker, options such as
   6937        -Wl,--as-needed should be used.
   6938      * Versions of the GNU C library up to and including 2.11.1 included
   6939        an [1]incorrect implementation of the cproj function. GCC optimizes
   6940        its builtin cproj according to the behavior specified and allowed
   6941        by the ISO C99 standard. If you want to avoid discrepancies between
   6942        the C library and GCC's builtin transformations when using cproj in
   6943        your code, use GLIBC 2.12 or later. If you are using an older GLIBC
   6944        and actually rely on the incorrect behavior of cproj, then you can
   6945        disable GCC's transformations using -fno-builtin-cproj.
   6946      * The C-only intermodule optimization framework (IMA, enabled by
   6947        -combine) has been removed in favor of the new generic link-time
   6948        optimization framework (LTO) introduced in [2]GCC 4.5.0.
   6949      * GCC now ships with the LGPL-licensed libquadmath library, which
   6950        provides quad-precision mathematical functions for targets with a
   6951        __float128 datatype. __float128 is available for targets on 32-bit
   6952        x86, x86-64 and Itanium architectures. The libquadmath library is
   6953        automatically built on such targets when building the Fortran
   6954        compiler.
   6955      * New -Wunused-but-set-variable and -Wunused-but-set-parameter
   6956        warnings were added for C, C++, Objective-C and Objective-C++.
   6957        These warnings diagnose variables respective parameters which are
   6958        only set in the code and never otherwise used. Usually such
   6959        variables are useless and often even the value assigned to them is
   6960        computed needlessly, sometimes expensively. The
   6961        -Wunused-but-set-variable warning is enabled by default by -Wall
   6962        flag and -Wunused-but-set-parameter by -Wall -Wextra flags.
   6963      * On ARM, a bug has been fixed in GCC's implementation of the AAPCS
   6964        rules for the layout of vectors that could lead to wrong code being
   6965        generated. Vectors larger than 8 bytes in size are now by default
   6966        aligned to an 8-byte boundary. This is an ABI change: code that
   6967        makes explicit use of vector types may be incompatible with binary
   6968        objects built with older versions of GCC. Auto-vectorized code is
   6969        not affected by this change. (This change affects GCC versions
   6970        4.6.4 and later, with the exception of versions 4.7.0 and 4.7.1.)
   6971      * On AVR, variables with the progmem attribute to locate data in
   6972        flash memory must be qualified as const.
   6973      * Support for a number of older systems and recently unmaintained or
   6974        untested target ports of GCC has been declared obsolete in GCC 4.6.
   6975        Unless there is activity to revive them, the next release of GCC
   6976        will have their sources permanently removed.
   6977        All GCC ports for the following processor architectures have been
   6978        declared obsolete:
   6979           + Argonaut ARC (arc-*)
   6980           + National Semiconductor CRX (crx-*)
   6981           + Motorola 68HC11 and 68HC12 (m68hc11-*-*, m6811-*-*,
   6982             m68hc12-*-*, m6812-*-*)
   6983           + Sunplus S+core (score-*)
   6984        The following ports for individual systems on particular
   6985        architectures have been obsoleted:
   6986           + Interix (i[34567]86-*-interix3*)
   6987           + NetWare x86 (i[3456x]86-*-netware*)
   6988           + Generic ARM PE (arm-*-pe* other than arm*-wince-pe*)
   6989           + MCore PE (mcore-*-pe*)
   6990           + SH SymbianOS (sh*-*-symbianelf*)
   6991           + GNU Hurd on Alpha and PowerPC (alpha*-*-gnu*, powerpc*-*-gnu*)
   6992           + M68K uClinux old ABI (m68k-*-uclinuxoldabi*)
   6993           + a.out NetBSD (arm*-*-netbsd*, i[34567]86-*-netbsd*,
   6994             vax-*-netbsd*, but not *-*-netbsdelf*)
   6995        The i[34567]86-*-pe alias for Cygwin targets has also been
   6996        obsoleted; users should configure for i[34567]86-*-cygwin* instead.
   6997        Certain configure options to control the set of libraries built
   6998        with GCC on some targets have been obsoleted. On ARM targets, the
   6999        options --disable-fpu, --disable-26bit, --disable-underscore,
   7000        --disable-interwork, --disable-biendian and --disable-nofmult have
   7001        been obsoleted. On MIPS targets, the options
   7002        --disable-single-float, --disable-biendian and --disable-softfloat
   7003        have been obsoleted.
   7004      * Support has been removed for all the [3]configurations obsoleted in
   7005        GCC 4.5.
   7006      * More information on porting to GCC 4.6 from previous versions of
   7007        GCC can be found in the [4]porting guide for this release.
   7008 
   7009 General Optimizer Improvements
   7010 
   7011      * A new general optimization level, -Ofast, has been introduced. It
   7012        combines the existing optimization level -O3 with options that can
   7013        affect standards compliance but result in better optimized code.
   7014        For example, -Ofast enables -ffast-math.
   7015      * Link-time optimization improvements:
   7016           + The [5]Scalable Whole Program Optimizer (WHOPR) project has
   7017             stabilized to the point of being usable. It has become the
   7018             default mode when using the LTO optimization model. Link time
   7019             optimization can now split itself into multiple parallel
   7020             compilations. Parallelism is controlled with -flto=n (where n
   7021             specifies the number of compilations to execute in parallel).
   7022             GCC can also cooperate with a GNU make job server by
   7023             specifying the -flto=jobserver option and adding + to the
   7024             beginning of the Makefile rule executing the linker.
   7025             Classical LTO mode can be enforced by -flto-partition=none.
   7026             This may result in small code quality improvements.
   7027           + A large number of bugs were fixed. GCC itself, Mozilla Firefox
   7028             and other large applications can be built with LTO enabled.
   7029           + The linker plugin support improvements
   7030                o Linker plugin is now enabled by default when the linker
   7031                  is detected to have plugin support. This is the case for
   7032                  GNU ld 2.21.51 or newer (on ELF and Cygwin targets) and
   7033                  the Gold linker on ELF targets. Plugin support of the
   7034                  Apple linker on Darwin is not compatible with GCC. The
   7035                  linker plugin can also be controlled by the
   7036                  -fuse-linker-plugin command-line option.
   7037                o Resolution information from the linker plugin is used to
   7038                  drive whole program assumptions. Use of the linker plugin
   7039                  results in more aggressive optimization on binaries and
   7040                  on shared libraries that use the hidden visibility
   7041                  attribute. Consequently the use of -fwhole-program is not
   7042                  necessary in addition to LTO.
   7043           + Hidden symbols used from non-LTO objects now have to be
   7044             explicitly annotated with externally_visible when the linker
   7045             plugin is not used.
   7046           + C++ inline functions and virtual tables are now privatized
   7047             more aggressively, leading to better inter-procedural
   7048             optimization and faster dynamic linking.
   7049           + Memory usage and intermediate language streaming performance
   7050             have been improved.
   7051           + Static constructors and destructors from individual units are
   7052             inlined into a single function. This can significantly improve
   7053             startup times of large C++ applications where static
   7054             constructors are very common. For example, static constructors
   7055             are used when including the iostream header.
   7056           + Support for the Ada language has been added.
   7057      * Interprocedural optimization improvements
   7058           + The interprocedural framework was re-tuned for link time
   7059             optimization. Several scalability issues were resolved.
   7060           + Improved auto-detection of const and pure functions. Newly,
   7061             noreturn functions are auto-detected.
   7062             The [6]-Wsuggest-attribute=[const|pure|noreturn] flag is
   7063             available that informs users when adding attributes to headers
   7064             might improve code generation.
   7065           + A number of inlining heuristic improvements. In particular:
   7066                o Partial inlining is now supported and enabled by default
   7067                  at -O2 and greater. The feature can be controlled via
   7068                  -fpartial-inlining.
   7069                  Partial inlining splits functions with short hot path to
   7070                  return. This allows more aggressive inlining of the hot
   7071                  path leading to better performance and often to code size
   7072                  reductions (because cold parts of functions are not
   7073                  duplicated).
   7074                o Scalability for large compilation units was improved
   7075                  significantly.
   7076                o Inlining of callbacks is now more aggressive.
   7077                o Virtual methods are considered for inlining when the
   7078                  caller is inlined and devirtualization is then possible.
   7079                o Inlining when optimizing for size (either in cold regions
   7080                  of a program or when compiling with -Os) was improved to
   7081                  better handle C++ programs with larger abstraction
   7082                  penalty, leading to smaller and faster code.
   7083           + The IPA reference optimization pass detecting global variables
   7084             used or modified by functions was strengthened and sped up.
   7085           + Functions whose address was taken are now optimized out when
   7086             all references to them are dead.
   7087           + A new inter-procedural static profile estimation pass detects
   7088             functions that are executed once or unlikely to be executed.
   7089             Unlikely executed functions are optimized for size. Functions
   7090             executed once are optimized for size except for the inner
   7091             loops.
   7092           + On most targets with named section support, functions used
   7093             only at startup (static constructors and main), functions used
   7094             only at exit and functions detected to be cold are placed into
   7095             separate text segment subsections. This extends the
   7096             -freorder-functions feature and is controlled by the same
   7097             switch. The goal is to improve the startup time of large C++
   7098             programs.
   7099             Proper function placement requires linker support. GNU ld
   7100             2.21.51 on ELF targets was updated to place those functions
   7101             together within the text section leading to better code
   7102             locality and faster startup times of large C++ programs. The
   7103             feature is also supported in the Apple linker. Support in the
   7104             gold linker is planned.
   7105      * A new switch -fstack-usage has been added. It makes the compiler
   7106        output stack usage information for the program, on a per-function
   7107        basis, in an auxiliary file.
   7108      * A new switch -fcombine-stack-adjustments has been added. It can be
   7109        used to enable or disable the compiler's stack-slot combining pass
   7110        which before was enabled automatically at -O1 and above, but could
   7111        not be controlled on its own.
   7112      * A new switch -fstrict-volatile-bitfields has been added. Using it
   7113        indicates that accesses to volatile bitfields should use a single
   7114        access of the width of the field's type. This option can be useful
   7115        for precisely defining and accessing memory-mapped peripheral
   7116        registers from C or C++.
   7117 
   7118 Compile time and memory usage improvements
   7119 
   7120      * Datastructures used by the dataflow framework in GCC were
   7121        reorganized for better memory usage and more cache locality.
   7122        Compile time is improved especially on units with large functions
   7123        (possibly resulting from a lot of inlining) not fitting into the
   7124        processor cache. The compile time of the GCC C compiler binary with
   7125        link-time optimization went down by over 10% (benchmarked on x86-64
   7126        target).
   7127 
   7128 New Languages and Language specific improvements
   7129 
   7130   Ada
   7131 
   7132      * Stack checking has been improved on selected architectures (Alpha,
   7133        IA-32/x86-64, RS/6000 and SPARC): it now will detect stack
   7134        overflows in all cases on these architectures.
   7135      * Initial support for Ada 2012 has been added.
   7136 
   7137   C family
   7138 
   7139      * A new warning, enabled by -Wdouble-promotion, has been added that
   7140        warns about cases where a value of type float is implicitly
   7141        promoted to double. This is especially helpful for CPUs that handle
   7142        the former in hardware, but emulate the latter in software.
   7143      * A new function attribute leaf was introduced. This attribute allows
   7144        better inter-procedural optimization across calls to functions that
   7145        return to the current unit only via returning or exception
   7146        handling. This is the case for most library functions that have no
   7147        callbacks.
   7148      * Support for a new data type __int128 for targets having wide enough
   7149        machine-mode support.
   7150      * The new function attribute callee_pop_aggregate allows to specify
   7151        if the caller or callee is responsible for popping the aggregate
   7152        return pointer value from the stack.
   7153      * Support for selectively enabling and disabling warnings via #pragma
   7154        GCC diagnostic has been added. For instance:
   7155 #pragma GCC diagnostic error "-Wuninitialized"
   7156   foo(a);                       /* error is given for this one */
   7157 #pragma GCC diagnostic push
   7158 #pragma GCC diagnostic ignored "-Wuninitialized"
   7159   foo(b);                       /* no diagnostic for this one */
   7160 #pragma GCC diagnostic pop
   7161   foo(c);                       /* error is given for this one */
   7162 #pragma GCC diagnostic pop
   7163   foo(d);                       /* depends on command-line options */
   7164 
   7165      * The -fmax-errors=N option is now supported. Using this option
   7166        causes the compiler to exit after N errors have been issued.
   7167 
   7168   C
   7169 
   7170      * There is now experimental support for some features from the
   7171        upcoming C1X revision of the ISO C standard. This support may be
   7172        selected with -std=c1x, or -std=gnu1x for C1X with GNU extensions.
   7173        Note that this support is experimental and may change incompatibly
   7174        in future releases for consistency with changes to the C1X standard
   7175        draft. The following features are newly supported as described in
   7176        the N1539 draft of C1X (with changes agreed at the March 2011 WG14
   7177        meeting); some other features were already supported with no
   7178        compiler changes being needed, or have some support but not in full
   7179        accord with N1539 (as amended).
   7180           + Static assertions (_Static_assert keyword)
   7181           + Typedef redefinition
   7182           + New macros in <float.h>
   7183           + Anonymous structures and unions
   7184      * The new -fplan9-extensions option directs the compiler to support
   7185        some extensions for anonymous struct fields which are implemented
   7186        by the Plan 9 compiler. A pointer to a struct may be automatically
   7187        converted to a pointer to an anonymous field when calling a
   7188        function, in order to make the types match. An anonymous struct
   7189        field whose type is a typedef name may be referred to using the
   7190        typedef name.
   7191 
   7192   C++
   7193 
   7194      * Improved [7]experimental support for the upcoming C++0x ISO C++
   7195        standard, including support for constexpr (thanks to Gabriel Dos
   7196        Reis and Jason Merrill), nullptr (thanks to Magnus Fromreide),
   7197        noexcept, unrestricted unions, range-based for loops (thanks to
   7198        Rodrigo Rivas Costa), opaque enum declarations (thanks also to
   7199        Rodrigo), implicitly deleted functions and implicit move
   7200        constructors.
   7201      * When an extern declaration within a function does not match a
   7202        declaration in the enclosing context, G++ now properly declares the
   7203        name within the namespace of the function rather than the namespace
   7204        which was open just before the function definition ([8]c++/43145).
   7205      * GCC now warns by default when casting integers to larger pointer
   7206        types. These warnings can be disabled with the option
   7207        -Wno-int-to-pointer-cast, which is now also available in C++.
   7208      * G++ no longer optimizes using the assumption that a value of
   7209        enumeration type will fall within the range specified by the
   7210        standard, since that assumption is easily violated with a
   7211        conversion from integer type ([9]c++/43680). The old behavior can
   7212        be restored with -fstrict-enums.
   7213      * The new -fnothrow-opt flag changes the semantics of a throw()
   7214        exception specification to match the proposed semantics of the
   7215        noexcept specification: just call terminate if an exception tries
   7216        to propagate out of a function with such an exception
   7217        specification. This dramatically reduces or eliminates the code
   7218        size overhead from adding the exception specification.
   7219      * The new -Wnoexcept flag will suggest adding a noexcept qualifier to
   7220        a function that the compiler can tell doesn't throw if it would
   7221        change the value of a noexcept expression.
   7222      * The -Wshadow option now warns if a local variable or type
   7223        declaration shadows another type in C++. Note that the compiler
   7224        will not warn if a local variable shadows a struct/class/enum, but
   7225        will warn if it shadows an explicit typedef.
   7226      * When an identifier is not found in the current scope, G++ now
   7227        offers suggestions about which identifier might have been intended.
   7228      * G++ now issues clearer diagnostics for missing semicolons after
   7229        class, struct, and union definitions.
   7230      * G++ now issues clearer diagnostics for missing semicolons after
   7231        class member declarations.
   7232      * G++ now issues clearer diagnostics when a colon is used in a place
   7233        where a double-colon was intended.
   7234      * G++ no longer accepts mutable on reference members ([10]c++/33558).
   7235        Use -fpermissive to allow the old, non-conforming behaviour.
   7236      * A few mangling fixes have been made, to attribute const/volatile on
   7237        function pointer types, decltype of a plain decl, and use of a
   7238        function parameter in the declaration of another parameter. By
   7239        default the compiler still uses the old mangling, but emits aliases
   7240        with the new mangling on targets that support strong aliases. Users
   7241        can switch over entirely to the new mangling with -fabi-version=5
   7242        or -fabi-version=0. -Wabi will now warn about code that uses the
   7243        old mangling.
   7244      * In 4.6.0 and 4.6.1 G++ no longer allows objects of const-qualified
   7245        type to be default initialized unless the type has a user-declared
   7246        default constructor. In 4.6.2 G++ implements the proposed
   7247        resolution of [11]DR 253, so default initialization is allowed if
   7248        it initializes all subobjects. Code that fails to compile can be
   7249        fixed by providing an initializer e.g.
   7250     struct A { A(); };
   7251     struct B : A { int i; };
   7252     const B b = B();
   7253        Use -fpermissive to allow the old, non-conforming behaviour.
   7254 
   7255     Runtime Library (libstdc++)
   7256 
   7257      * [12]Improved experimental support for the upcoming ISO C++
   7258        standard, C++0x, including using constexpr and nullptr.
   7259      * Performance improvements to the [13]Debug Mode, thanks to Franois
   7260        Dumont.
   7261      * Atomic operations used for reference-counting are annotated so that
   7262        they can be understood by race detectors such as Helgrind, see
   7263        [14]Data Race Hunting.
   7264      * Most libstdc++ standard headers have been changed to no longer
   7265        include the cstddef header as an implementation detail. Code that
   7266        relied on that header being included as side-effect of including
   7267        other standard headers will need to include cstddef explicitly.
   7268 
   7269   Fortran
   7270 
   7271      * On systems supporting the libquadmath library, GNU Fortran now also
   7272        supports a quad-precision, kind=16 floating-point data type
   7273        (REAL(16), COMPLEX(16)). As the data type is not fully supported in
   7274        hardware, calculations might be one to two orders of magnitude
   7275        slower than with the 4, 8 or 10 bytes floating-point data types.
   7276        This change does not affect systems which support REAL(16) in
   7277        hardware nor those which do not support libquadmath.
   7278      * Much improved compile time for large array constructors.
   7279      * In order to reduce execution time and memory consumption, use of
   7280        temporary arrays in assignment expressions is avoided for many
   7281        cases. The compiler now reverses loops in order to avoid generating
   7282        a temporary array where possible.
   7283      * Improved diagnostics, especially with -fwhole-file.
   7284      * The -fwhole-file flag is now enabled by default. This improves code
   7285        generation and diagnostics. It can be disabled using the deprecated
   7286        -fno-whole-file flag.
   7287      * Support the generation of Makefile dependencies via the [15]-M...
   7288        flags of GCC; you may need to specify the -cpp option in addition.
   7289        The dependencies take modules, Fortran's include, and CPP's
   7290        #include into account. Note: Using -M for the module path is no
   7291        longer supported, use -J instead.
   7292      * The flag -Wconversion has been modified to only issue warnings
   7293        where a conversion leads to information loss. This drastically
   7294        reduces the number of warnings; -Wconversion is thus now enabled
   7295        with -Wall. The flag -Wconversion-extra has been added and also
   7296        warns about other conversions; -Wconversion-extra typically issues
   7297        a huge number of warnings, most of which can be ignored.
   7298      * A new command-line option -Wunused-dummy-argument warns about
   7299        unused dummy arguments and is included in -Wall. Before,
   7300        -Wunused-variable also warned about unused dummy arguments.
   7301      * Fortran 2003 support has been extended:
   7302           + Improved support for polymorphism between libraries and
   7303             programs and for complicated inheritance patterns (cf.
   7304             [16]object-oriented programming).
   7305           + Experimental support of the ASSOCIATE construct.
   7306           + In pointer assignments it is now possible to specify the lower
   7307             bounds of the pointer and, for a rank-1 or a simply contiguous
   7308             data-target, to remap the bounds.
   7309           + Automatic (re)allocation: In intrinsic assignments to
   7310             allocatable variables the left-hand side will be automatically
   7311             allocated (if unallocated) or reallocated (if the shape or
   7312             type parameter is different). To avoid the small performance
   7313             penalty, you can use a(:) = ... instead of a = ... for arrays
   7314             and character strings  or disable the feature using -std=f95
   7315             or -fno-realloc-lhs.
   7316           + Deferred type parameter: For scalar allocatable and pointer
   7317             variables the character length can be deferred.
   7318           + Namelist variables with allocatable and pointer attribute and
   7319             nonconstant length type parameter are supported.
   7320      * Fortran 2008 support has been extended:
   7321           + Experimental [17]coarray support (for one image only, i.e.
   7322             num_images() == 1); use the [18]-fcoarray=single flag to
   7323             enable it.
   7324           + The STOP and the new ERROR STOP statements now support all
   7325             constant expressions.
   7326           + Support for the CONTIGUOUS attribute.
   7327           + Support for ALLOCATE with MOLD.
   7328           + Support for the STORAGE_SIZE intrinsic inquiry function.
   7329           + Support of the NORM2 and PARITY intrinsic functions.
   7330           + The following bit intrinsics were added: POPCNT and POPPAR for
   7331             counting the number of 1 bits and returning the parity; BGE,
   7332             BGT, BLE, and BLT for bitwise comparisons; DSHIFTL and DSHIFTR
   7333             for combined left and right shifts, MASKL and MASKR for simple
   7334             left and right justified masks, MERGE_BITS for a bitwise merge
   7335             using a mask, SHIFTA, SHIFTL and SHIFTR for shift operations,
   7336             and the transformational bit intrinsics IALL, IANY and
   7337             IPARITY.
   7338           + Support of the EXECUTE_COMMAND_LINE intrinsic subroutine.
   7339           + Support for the IMPURE attribute for procedures, which allows
   7340             for ELEMENTAL procedures without the restrictions of PURE.
   7341           + Null pointers (including NULL()) and not allocated variables
   7342             can be used as actual argument to optional non-pointer,
   7343             non-allocatable dummy arguments, denoting an absent argument.
   7344           + Non-pointer variables with TARGET attribute can be used as
   7345             actual argument to POINTER dummies with INTENT(IN)
   7346           + Pointers including procedure pointers and those in a derived
   7347             type (pointer components) can now be initialized by a target
   7348             instead of only by NULL.
   7349           + The EXIT statement (with construct-name) can now be used to
   7350             leave not only the DO but also the ASSOCIATE, BLOCK, IF,
   7351             SELECT CASE and SELECT TYPE constructs.
   7352           + Internal procedures can now be used as actual argument.
   7353           + The named constants INTEGER_KINDS, LOGICAL_KINDS, REAL_KINDS
   7354             and CHARACTER_KINDS of the intrinsic module ISO_FORTRAN_ENV
   7355             have been added; these arrays contain the supported kind
   7356             values for the respective types.
   7357           + The module procedures C_SIZEOF of the intrinsic module
   7358             ISO_C_BINDINGS and COMPILER_VERSION and COMPILER_OPTIONS of
   7359             ISO_FORTRAN_ENV have been implemented.
   7360           + Minor changes: obsolescence diagnostics for ENTRY was added
   7361             for -std=f2008; a line may start with a semicolon; for
   7362             internal and module procedures END can be used instead of END
   7363             SUBROUTINE and END FUNCTION; SELECTED_REAL_KIND now also takes
   7364             a RADIX argument; intrinsic types are supported for
   7365             TYPE(intrinsic-type-spec); multiple type-bound procedures can
   7366             be declared in a single PROCEDURE statement; implied-shape
   7367             arrays are supported for named constants (PARAMETER). The
   7368             transformational, three argument versions of BESSEL_JN and
   7369             BESSEL_YN were added  the elemental, two-argument version had
   7370             been added in GCC 4.4; note that the transformational
   7371             functions use a recurrence algorithm.
   7372 
   7373   Go
   7374 
   7375    Support for the [19]Go programming language has been added to GCC. It
   7376    is not enabled by default when you build GCC; use the
   7377    --enable-languages configure option to build it. The driver program for
   7378    compiling Go code is gccgo.
   7379 
   7380    Go is currently known to work on GNU/Linux and RTEMS. Solaris support
   7381    is in progress. It may or may not work on other platforms.
   7382 
   7383   Objective-C and Objective-C++
   7384 
   7385      * The -fobjc-exceptions flag is now required to enable Objective-C
   7386        exception and synchronization syntax (introduced by the keywords
   7387        @try, @catch, @finally and @synchronized).
   7388      * A number of Objective-C 2.0 features and extensions are now
   7389        supported by GCC. These features are enabled by default; you can
   7390        disable them by using the new -fobjc-std=objc1 command-line option.
   7391      * The Objective-C 2.0 dot-syntax is now supported. It is an
   7392        alternative syntax for using getters and setters; object.count is
   7393        automatically converted into [object count] or [object setCount:
   7394        ...] depending on context; for example if (object.count > 0) is
   7395        automatically compiled into the equivalent of if ([object count] >
   7396        0) while object.count = 0; is automatically compiled into the
   7397        equivalent ot [object setCount: 0];. The dot-syntax can be used
   7398        with instance and class objects and with any setters or getters, no
   7399        matter if they are part of a declared property or not.
   7400      * Objective-C 2.0 declared properties are now supported. They are
   7401        declared using the new @property keyword, and are most commonly
   7402        used in conjunction with the new Objective-C 2.0 dot-syntax. The
   7403        nonatomic, readonly, readwrite, assign, retain, copy, setter and
   7404        getter attributes are all supported. Marking declared properties
   7405        with __attribute__ ((deprecated)) is supported too.
   7406      * The Objective-C 2.0 @synthesize and @dynamic keywords are
   7407        supported. @synthesize causes the compiler to automatically
   7408        synthesize a declared property, while @dynamic is used to disable
   7409        all warnings for a declared property for which no implementation is
   7410        provided at compile time. Synthesizing declared properties requires
   7411        runtime support in most useful cases; to be able to use it with the
   7412        GNU runtime, appropriate helper functions have been added to the
   7413        GNU Objective-C runtime ABI, and are implemented by the GNU
   7414        Objective-C runtime library shipped with GCC.
   7415      * The Objective-C 2.0 fast enumeration syntax is supported in
   7416        Objective-C. This is currently not yet available in Objective-C++.
   7417        Fast enumeration requires support in the runtime, and such support
   7418        has been added to the GNU Objective-C runtime library (shipped with
   7419        GCC).
   7420      * The Objective-C 2.0 @optional keyword is supported. It allows you
   7421        to mark methods or properties in a protocol as optional as opposed
   7422        to required.
   7423      * The Objective-C 2.0 @package keyword is supported. It has currently
   7424        the same effect as the @public keyword.
   7425      * Objective-C 2.0 method attributes are supported. Currently the
   7426        supported attributes are deprecated, sentinel, noreturn and format.
   7427      * Objective-C 2.0 method argument attributes are supported. The most
   7428        widely used attribute is unused, to mark an argument as unused in
   7429        the implementation.
   7430      * Objective-C 2.0 class and protocol attributes are supported.
   7431        Currently the only supported attribute is deprecated.
   7432      * Objective-C 2.0 class extensions are supported. A class extension
   7433        has the same syntax as a category declaration with no category
   7434        name, and the methods and properties declared in it are added
   7435        directly to the main class. It is mostly used as an alternative to
   7436        a category to add methods to a class without advertising them in
   7437        the public headers, with the advantage that for class extensions
   7438        the compiler checks that all the privately declared methods are
   7439        actually implemented.
   7440      * As a result of these enhancements, GCC can now be used to build
   7441        Objective-C and Objective-C++ software that uses Foundation and
   7442        other important system frameworks with the NeXT runtime on Darwin 9
   7443        and Darwin 10 (OSX 10.5 and 10.6).
   7444      * Many bugs in the compiler have been fixed in this release; in
   7445        particular, LTO can now be used when compiling Objective-C and
   7446        Objective-C++ and the parser is much more robust in dealing with
   7447        invalid code.
   7448 
   7449     Runtime Library (libobjc)
   7450 
   7451      * The GNU Objective-C runtime library now defines the macro
   7452        __GNU_LIBOBJC__ (with a value that is increased at every release
   7453        where there is any change to the API) in objc/objc.h, making it
   7454        easy to determine if the GNU Objective-C runtime library is being
   7455        used, and if so, which version. Previous versions of the GNU
   7456        Objective-C runtime library (and other Objective-C runtime
   7457        libraries such as the Apple one) do not define this macro.
   7458      * A new Objective-C 2.0 API, almost identical to the one implemented
   7459        by the Apple Objective-C runtime, has been implemented in the GNU
   7460        Objective-C runtime library. The new API hides the internals of
   7461        most runtime structures but provides a more extensive set of
   7462        functions to operate on them. It is much easier, for example, to
   7463        create or modify classes at runtime. The new API also makes it
   7464        easier to port software from Apple to GNU as almost no changes
   7465        should be required. The old API is still supported for backwards
   7466        compatibility; including the old objc/objc-api.h header file
   7467        automatically selects the old API, while including the new
   7468        objc/runtime.h header file automatically selects the new API.
   7469        Support for the old API is being phased out and upgrading the
   7470        software to use the new API is strongly recommended. To check for
   7471        the availability of the new API, the __GNU_LIBOBJC__ macro can be
   7472        used as older versions of the GNU Objective-C runtime library,
   7473        which do not support the new API, do not define such a macro.
   7474      * Runtime support for @synchronized has been added.
   7475      * Runtime support for Objective-C 2.0 synthesized property accessors
   7476        has been added.
   7477      * Runtime support for Objective-C 2.0 fast enumeration has been
   7478        added.
   7479 
   7480 New Targets and Target Specific Improvements
   7481 
   7482   ARM
   7483 
   7484      * GCC now supports the Cortex-M4 processor implementing the v7-em
   7485        version of the architecture using the option -mcpu=cortex-m4.
   7486      * Scheduling descriptions for the Cortex-M4, the Neon and the
   7487        floating point units of the Cortex-A9 and a pipeline description
   7488        for the Cortex-A5 have been added.
   7489      * Synchronization primitives such as __sync_fetch_and_add and friends
   7490        are now inlined for supported architectures rather than calling
   7491        into a kernel helper function.
   7492      * SSA loop prefetching is enabled by default for the Cortex-A9 at
   7493        -O3.
   7494      * Several improvements were committed to improve code generation for
   7495        the ARM architecture including a rewritten implementation for load
   7496        and store multiples.
   7497      * Several enhancements were committed to improve SIMD code generation
   7498        for NEON by adding support for widening instructions, misaligned
   7499        loads and stores, vector conditionals and support for 64 bit
   7500        arithmetic.
   7501      * Support was added for the Faraday cores fa526, fa606te, fa626te,
   7502        fmp626te, fmp626 and fa726te and can be used with the respective
   7503        names as parameters to the -mcpu= option.
   7504      * Basic support was added for Cortex-A15 and is available through
   7505        -mcpu=cortex-a15.
   7506      * GCC for AAPCS configurations now more closely adheres to the AAPCS
   7507        specification by enabling -fstrict-volatile-bitfields by default.
   7508 
   7509   IA-32/x86-64
   7510 
   7511      * The new -fsplit-stack option permits programs to use a
   7512        discontiguous stack. This is useful for threaded programs, in that
   7513        it is no longer necessary to specify the maximum stack size when
   7514        creating a thread. This feature is currently only implemented for
   7515        32-bit and 64-bit x86 GNU/Linux targets.
   7516      * Support for emitting profiler counter calls before function
   7517        prologues. This is enabled via a new command-line option -mfentry.
   7518      * Optimization for the Intel Core 2 processors is now available
   7519        through the -march=core2 and -mtune=core2 options.
   7520      * Support for Intel Core i3/i5/i7 processors is now available through
   7521        the -march=corei7 and -mtune=corei7 options.
   7522      * Support for Intel Core i3/i5/i7 processors with AVX is now
   7523        available through the -march=corei7-avx and -mtune=corei7-avx
   7524        options.
   7525      * Support for AMD Bobcat (family 14) processors is now available
   7526        through the -march=btver1 and -mtune=btver1 options.
   7527      * Support for AMD Bulldozer (family 15) processors is now available
   7528        through the -march=bdver1 and -mtune=bdver1 options.
   7529      * The default setting (when not optimizing for size) for 32-bit
   7530        GNU/Linux and Darwin x86 targets has been changed to
   7531        -fomit-frame-pointer. The default can be reverted to
   7532        -fno-omit-frame-pointer by configuring GCC with the
   7533        --enable-frame-pointer configure option.
   7534      * Darwin, FreeBSD, Solaris 2, MinGW and Cygwin now all support
   7535        __float128 on 32-bit and 64-bit x86 targets.
   7536      * AVX floating-point arithmetic can now be enabled by default at
   7537        configure time with the new --with-fpmath=avx option.
   7538      * The SSA loop prefetching pass is enabled when using -O3 when
   7539        optimizing for CPUs where prefetching is beneficial (AMD CPUs newer
   7540        than K6).
   7541      * Support for TBM (Trailing Bit Manipulation) built-in functions and
   7542        code generation is available via -mtbm.
   7543      * Support for AMD's BMI (Bit Manipulation) built-in functions and
   7544        code generation is available via -mbmi.
   7545 
   7546   MicroBlaze
   7547 
   7548      * Support has been added for the Xilinx MicroBlaze softcore processor
   7549        (microblaze-elf) embedded target. This configurable processor is
   7550        supported on several Xilinx Spartan and Virtex FPGAs.
   7551 
   7552   MIPS
   7553 
   7554      * GCC now supports the Loongson 3A processor. Its canonical -march=
   7555        and -mtune= name is loongson3a.
   7556 
   7557   MN10300 / AM33
   7558 
   7559      * The inline assembly register constraint "A" has been renamed "c".
   7560        This constraint is used to select a floating-point register that
   7561        can be used as the destination of a multiply-accumulate
   7562        instruction.
   7563      * New inline assembly register constraints "A" and "D" have been
   7564        added. These constraint letters resolve to all general registers
   7565        when compiling for AM33, and resolve to address registers only or
   7566        data registers only when compiling for MN10300.
   7567      * The MDR register is represented in the compiler. One can access the
   7568        register via the "z" constraint in inline assembly. It can be
   7569        marked as clobbered or used as a local register variable via the
   7570        "mdr" name. The compiler uses the RETF instruction if the function
   7571        does not modify the MDR register, so it is important that inline
   7572        assembly properly annotate any usage of the register.
   7573 
   7574   PowerPC/PowerPC64
   7575 
   7576      * GCC now supports the Applied Micro Titan processor with
   7577        -mcpu=titan.
   7578      * The -mrecip option has been added, which indicates whether the
   7579        reciprocal and reciprocal square root instructions should be used.
   7580      * The -mveclibabi=mass option can be used to enable the compiler to
   7581        autovectorize mathematical functions using the Mathematical
   7582        Acceleration Subsystem library.
   7583      * The -msingle-pic-base option has been added, which instructs the
   7584        compiler to avoid loading the PIC base register in function
   7585        prologues. The PIC base register must be initialized by the runtime
   7586        system.
   7587      * The -mblock-move-inline-limit option has been added, which enables
   7588        the user to control the maximum size of inlined memcpy calls and
   7589        similar.
   7590      * PowerPC64 GNU/Linux support for applications requiring a large TOC
   7591        section has been improved. A new command-line option,
   7592        -mcmodel=MODEL, controls this feature; valid values for MODEL are
   7593        small, medium, or large.
   7594      * The Altivec builtin functions vec_ld and vec_st have been modified
   7595        to generate the Altivec memory instructions LVX and STVX, even if
   7596        the -mvsx option is used. In the initial GCC 4.5 release, these
   7597        builtin functions were changed to generate VSX memory reference
   7598        instructions instead of Altivec memory instructions, but there are
   7599        differences between the two instructions. If the VSX instruction
   7600        set is available, you can now use the new builtin functions
   7601        vec_vsx_ld and vec_vsx_st which always generates the VSX memory
   7602        instructions.
   7603      * The GCC compiler on AIX now defaults to a process layout with a
   7604        larger data space allowing larger programs to be compiled.
   7605      * The GCC long double type on AIX 6.1 and above has reverted to 64
   7606        bit double precision, matching the AIX XL compiler default, because
   7607        of missing C99 symbols required by the GCC runtime.
   7608      * The default processor scheduling model and tuning for PowerPC64
   7609        GNU/Linux and for AIX 6.1 and above now is POWER7.
   7610      * Starting with GCC 4.6.1, vectors of type vector long long or vector
   7611        long are passed and returned in the same method as other vectors
   7612        with the VSX instruction set. Previously the GCC compiler did not
   7613        adhere to the ABI for 128-bit vectors with 64-bit integer base
   7614        types (PR 48857). This is also fixed in the GCC 4.5.4 release.
   7615 
   7616   S/390, zSeries and System z9/z10, IBM zEnterprise z196
   7617 
   7618      * Support for the zEnterprise z196 processor has been added. When
   7619        using the -march=z196 option, the compiler will generate code
   7620        making use of the following instruction facilities:
   7621           + Conditional load/store
   7622           + Distinct-operands
   7623           + Floating-point-extension
   7624           + Interlocked-access
   7625           + Population-count
   7626        The -mtune=z196 option avoids the compare and branch instructions
   7627        as well as the load address instruction with an index register as
   7628        much as possible and performs instruction scheduling appropriate
   7629        for the new out-of-order pipeline architecture.
   7630      * When using the -m31 -mzarch options the generated code still
   7631        conforms to the 32-bit ABI but uses the general purpose registers
   7632        as 64-bit registers internally. This requires a Linux kernel saving
   7633        the whole 64-bit registers when doing a context switch. Kernels
   7634        providing that feature indicate that by the 'highgprs' string in
   7635        /proc/cpuinfo.
   7636      * The SSA loop prefetching pass is enabled when using -O3.
   7637 
   7638   SPARC
   7639 
   7640      * GCC now supports the LEON series of SPARC V8 processors. The code
   7641        generated by the compiler can either be tuned to it by means of the
   7642        --with-tune=leon configure option and -mtune=leon compilation
   7643        option, or the compiler can be built for the sparc-leon-{elf,linux}
   7644        and sparc-leon3-{elf,linux} targets directly.
   7645      * GCC has stopped sign/zero-extending parameter registers in the
   7646        callee for functions taking parameters with sub-word size in 32-bit
   7647        mode, since this is redundant with the specification of the ABI.
   7648        GCC has never done so in 64-bit mode since this is also redundant.
   7649      * The command-line option -mfix-at697f has been added to enable the
   7650        documented workaround for the single erratum of the Atmel AT697F
   7651        processor.
   7652 
   7653 Operating Systems
   7654 
   7655   Android
   7656 
   7657      * GCC now supports the Bionic C library and provides a convenient way
   7658        of building native libraries and applications for the Android
   7659        platform. Refer to the documentation of the -mandroid and -mbionic
   7660        options for details on building native code. At the moment, Android
   7661        support is enabled only for ARM.
   7662 
   7663   Darwin/Mac OS X
   7664 
   7665      * General
   7666           + Initial support for CFString types has been added.
   7667             This allows GCC to build projects including the system Core
   7668             Foundation frameworks. The GCC Objective-C family supports
   7669             CFString "toll-free bridged" as per the Mac OS X system tools.
   7670             CFString is also recognized in the context of format
   7671             attributes and arguments (see the documentation for format
   7672             attributes for limitations). At present, 8-bit character types
   7673             are supported.
   7674           + Object file size reduction.
   7675             The Darwin zeroed memory allocators have been re-written to
   7676             make more use of .zerofill sections. For non-debug code, this
   7677             can reduce object file size significantly.
   7678           + Objective-C family 64-bit support (NeXT ABI 2).
   7679             Initial support has been added to support 64-bit Objective-C
   7680             code using the Darwin/OS X native (NeXT) runtime. ABI version
   7681             2 will be selected automatically when 64-bit code is built.
   7682           + Objective-C family 32-bit ABI 1.
   7683             For 32-bit code ABI 1 is also now also allowed. At present it
   7684             must be selected manually using -fobjc-abi-version=1 where
   7685             applicable - i.e. on Darwin 9/10 (OS X 10.5/10.6).
   7686      * x86 Architecture
   7687           + The -mdynamic-no-pic option has been enabled.
   7688             Code supporting -mdynamic-no-pic optimization has been added
   7689             and is applicable to -m32 builds. The compiler bootstrap uses
   7690             the option where appropriate.
   7691           + The default value for -mtune= has been changed.
   7692             Since Darwin systems are primarily Xeon, Core-2 or similar the
   7693             default tuning has been changed to -mtune=core2.
   7694           + Enable 128-bit long double (__float128) support on Darwin.
   7695      * PPC Architecture
   7696           + Darwin64 ABI.
   7697             Several significant bugs have been fixed, such that GCC now
   7698             produces code compatible with the Darwin64 PowerPC ABI.
   7699           + libffi and boehm-gc.
   7700             The Darwin ports of the libffi and boehm-gc libraries have
   7701             been upgraded to include a Darwin64 implementation. This means
   7702             that powerpc*-*-darwin9 platforms may now, for example, build
   7703             Java applications with -m64 enabled.
   7704           + Plug-in support has been enabled.
   7705           + The -fsection-anchors option is now available although,
   7706             presently, not heavily tested.
   7707 
   7708   Solaris 2
   7709 
   7710     New Features
   7711 
   7712      * Support symbol versioning with the Sun linker.
   7713      * Allow libstdc++ to leverage full ISO C99 support on Solaris 10+.
   7714      * Support thread-local storage (TLS) with the Sun assembler on
   7715        Solaris 2/x86.
   7716      * Support TLS on Solaris 8/9 if prerequisites are met.
   7717      * Support COMDAT group with the GNU assembler and recent Sun linker.
   7718      * Support the Sun assembler visibility syntax.
   7719      * Default Solaris 2/x86 to -march=pentium4 (Solaris 10+) resp.
   7720        -march=pentiumpro (Solaris 8/9).
   7721      * Don't use SSE on Solaris 8/9 x86 by default.
   7722      * Enable 128-bit long double (__float128) support on Solaris 2/x86.
   7723 
   7724     ABI Change
   7725 
   7726      * Change the ABI for returning 8-byte vectors like __m64 in MMX
   7727        registers on Solaris 10+/x86 to match the Sun Studio 12.1+
   7728        compilers. This is an incompatible change. If you use such types,
   7729        you must either recompile all your code with the new compiler or
   7730        use the new -mvect8-ret-in-mem option to remain compatible with
   7731        previous versions of GCC and Sun Studio.
   7732 
   7733   Windows x86/x86_64
   7734 
   7735      * Initial support for decimal floating point.
   7736      * Support for the __thiscall calling-convention.
   7737      * Support for hot-patchable function prologues via the
   7738        ms_hook_prologue attribute for x86_64 in addition to 32-bit x86.
   7739      * Improvements of stack-probing and stack-allocation mechanisms.
   7740      * Support of push/pop-macro pragma as preprocessor command.
   7741        With #pragma push_macro("macro-name") the current definition of
   7742        macro-name is saved and can be restored with #pragma
   7743        pop_macro("macro-name") to its saved definition.
   7744      * Enable 128-bit long double (__float128) support on MinGW and
   7745        Cygwin.
   7746 
   7747 Other significant improvements
   7748 
   7749   Installation changes
   7750 
   7751      * An install-strip make target is provided that installs stripped
   7752        executables, and may install libraries with unneeded or debugging
   7753        sections stripped.
   7754      * On Power7 systems, there is a potential problem if you build the
   7755        GCC compiler with a host compiler using options that enable the VSX
   7756        instruction set generation. If the host compiler has been patched
   7757        so that the vec_ld and vec_st builtin functions generate Altivec
   7758        memory instructions instead of VSX memory instructions, then you
   7759        should be able to build the compiler with VSX instruction
   7760        generation.
   7761 
   7762 Changes for GCC Developers
   7763 
   7764    Note: these changes concern developers that develop GCC itself or
   7765    software that integrates with GCC, such as plugins, and not the general
   7766    GCC users.
   7767      * The gengtype utility, which previously was internal to the GCC
   7768        build process, has been enchanced to provide GC root information
   7769        for plugins as necessary.
   7770      * The old GC allocation interface of ggc_alloc and friends was
   7771        replaced with a type-safe alternative.
   7772 
   7773 GCC 4.6.1
   7774 
   7775    This is the [20]list of problem reports (PRs) from GCC's bug tracking
   7776    system that are known to be fixed in the 4.6.1 release. This list might
   7777    not be complete (that is, it is possible that some PRs that have been
   7778    fixed are not listed here).
   7779 
   7780 GCC 4.6.2
   7781 
   7782    This is the [21]list of problem reports (PRs) from GCC's bug tracking
   7783    system that are known to be fixed in the 4.6.2 release. This list might
   7784    not be complete (that is, it is possible that some PRs that have been
   7785    fixed are not listed here).
   7786 
   7787 GCC 4.6.3
   7788 
   7789    This is the [22]list of problem reports (PRs) from GCC's bug tracking
   7790    system that are known to be fixed in the 4.6.3 release. This list might
   7791    not be complete (that is, it is possible that some PRs that have been
   7792    fixed are not listed here).
   7793 
   7794 GCC 4.6.4
   7795 
   7796    This is the [23]list of problem reports (PRs) from GCC's bug tracking
   7797    system that are known to be fixed in the 4.6.4 release. This list might
   7798    not be complete (that is, it is possible that some PRs that have been
   7799    fixed are not listed here).
   7800 
   7801 
   7802     For questions related to the use of GCC, please consult these web
   7803     pages and the [24]GCC manuals. If that fails, the
   7804     [25]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   7805     web pages and the development of GCC are welcome on our developer
   7806     list at [26]gcc (a] gcc.gnu.org. All of [27]our lists have public
   7807     archives.
   7808 
   7809    Copyright (C) [28]Free Software Foundation, Inc. Verbatim copying and
   7810    distribution of this entire article is permitted in any medium,
   7811    provided this notice is preserved.
   7812 
   7813    These pages are [29]maintained by the GCC team. Last modified
   7814    2019-11-28[30].
   7815 
   7816 References
   7817 
   7818    1. https://sourceware.org/bugzilla/show_bug.cgi?id=10401
   7819    2. http://gcc.gnu.org/gcc-4.5/changes.html
   7820    3. http://gcc.gnu.org/gcc-4.5/changes.html#obsoleted
   7821    4. http://gcc.gnu.org/gcc-4.6/porting_to.html
   7822    5. http://gcc.gnu.org/projects/lto/whopr.pdf
   7823    6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options
   7824    7. http://gcc.gnu.org/gcc-4.6/cxx0x_status.html
   7825    8. https://gcc.gnu.org/PR43145
   7826    9. https://gcc.gnu.org/PR43680
   7827   10. https://gcc.gnu.org/PR33558
   7828   11. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253
   7829   12. https://gcc.gnu.org/onlinedocs/gcc-4.6.4/libstdc++/manual/manual/status.html#status.iso.200x
   7830   13. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode.html
   7831   14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html#debug.races
   7832   15. https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html
   7833   16. https://gcc.gnu.org/wiki/OOP
   7834   17. https://gcc.gnu.org/wiki/Coarray
   7835   18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcoarray_007d-233
   7836   19. https://golang.org/
   7837   20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.1
   7838   21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.2
   7839   22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.3
   7840   23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.6.4
   7841   24. https://gcc.gnu.org/onlinedocs/
   7842   25. mailto:gcc-help (a] gcc.gnu.org
   7843   26. mailto:gcc (a] gcc.gnu.org
   7844   27. https://gcc.gnu.org/lists.html
   7845   28. https://www.fsf.org/
   7846   29. https://gcc.gnu.org/about.html
   7847   30. http://validator.w3.org/check/referer
   7848 ======================================================================
   7849 http://gcc.gnu.org/gcc-4.5/index.html
   7850                              GCC 4.5 Release Series
   7851 
   7852    (This release series is no longer supported.)
   7853 
   7854    Jul 2, 2012
   7855 
   7856    The [1]GNU project and the GCC developers are pleased to announce the
   7857    release of GCC 4.5.4.
   7858 
   7859    This release is a bug-fix release, containing fixes for regressions in
   7860    GCC 4.5.3 relative to previous releases of GCC.
   7861 
   7862 Release History
   7863 
   7864    GCC 4.5.4
   7865           Jul 2, 2012 ([2]changes)
   7866 
   7867    GCC 4.5.3
   7868           Apr 28, 2011 ([3]changes)
   7869 
   7870    GCC 4.5.2
   7871           Dec 16, 2010 ([4]changes)
   7872 
   7873    GCC 4.5.1
   7874           Jul 31, 2010 ([5]changes)
   7875 
   7876    GCC 4.5.0
   7877           April 14, 2010 ([6]changes)
   7878 
   7879 References and Acknowledgements
   7880 
   7881    GCC used to stand for the GNU C Compiler, but since the compiler
   7882    supports several other languages aside from C, it now stands for the
   7883    GNU Compiler Collection.
   7884 
   7885    A list of [7]successful builds is updated as new information becomes
   7886    available.
   7887 
   7888    The GCC developers would like to thank the numerous people that have
   7889    contributed new features, improvements, bug fixes, and other changes as
   7890    well as test results to GCC. This [8]amazing group of volunteers is
   7891    what makes GCC successful.
   7892 
   7893    For additional information about GCC please refer to the [9]GCC project
   7894    web site or contact the [10]GCC development mailing list.
   7895 
   7896    To obtain GCC please use [11]our mirror sites or [12]our version
   7897    control system.
   7898 
   7899 
   7900     For questions related to the use of GCC, please consult these web
   7901     pages and the [13]GCC manuals. If that fails, the
   7902     [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   7903     web pages and the development of GCC are welcome on our developer
   7904     list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public
   7905     archives.
   7906 
   7907    Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and
   7908    distribution of this entire article is permitted in any medium,
   7909    provided this notice is preserved.
   7910 
   7911    These pages are [18]maintained by the GCC team. Last modified
   7912    2020-01-14[19].
   7913 
   7914 References
   7915 
   7916    1. http://www.gnu.org/
   7917    2. http://gcc.gnu.org/gcc-4.5/changes.html
   7918    3. http://gcc.gnu.org/gcc-4.5/changes.html
   7919    4. http://gcc.gnu.org/gcc-4.5/changes.html
   7920    5. http://gcc.gnu.org/gcc-4.5/changes.html
   7921    6. http://gcc.gnu.org/gcc-4.5/changes.html
   7922    7. http://gcc.gnu.org/gcc-4.5/buildstat.html
   7923    8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   7924    9. http://gcc.gnu.org/index.html
   7925   10. mailto:gcc (a] gcc.gnu.org
   7926   11. http://gcc.gnu.org/mirrors.html
   7927   12. http://gcc.gnu.org/git.html
   7928   13. https://gcc.gnu.org/onlinedocs/
   7929   14. mailto:gcc-help (a] gcc.gnu.org
   7930   15. mailto:gcc (a] gcc.gnu.org
   7931   16. https://gcc.gnu.org/lists.html
   7932   17. https://www.fsf.org/
   7933   18. https://gcc.gnu.org/about.html
   7934   19. http://validator.w3.org/check/referer
   7935 ======================================================================
   7936 http://gcc.gnu.org/gcc-4.5/changes.html
   7937                              GCC 4.5 Release Series
   7938                         Changes, New Features, and Fixes
   7939 
   7940 Caveats
   7941 
   7942      * GCC now requires the [1]MPC library in order to build. See the
   7943        [2]prerequisites page for version requirements.
   7944      * Support for a number of older systems and recently unmaintained or
   7945        untested target ports of GCC has been declared obsolete in GCC 4.5.
   7946        Unless there is activity to revive them, the next release of GCC
   7947        will have their sources permanently removed.
   7948        The following ports for individual systems on particular
   7949        architectures have been obsoleted:
   7950           + IRIX releases before 6.5 (mips-sgi-irix5*,
   7951             mips-sgi-irix6.[0-4])
   7952           + Solaris 7 (*-*-solaris2.7)
   7953           + Tru64 UNIX releases before V5.1 (alpha*-dec-osf4*,
   7954             alpha-dec-osf5.0*)
   7955           + Details for the IRIX, Solaris 7, and Tru64 UNIX obsoletions
   7956             can be found in the [3]announcement.
   7957        Support for the classic POWER architecture implemented in the
   7958        original RIOS and RIOS2 processors of the old IBM RS/6000 product
   7959        line has been obsoleted in the rs6000 port. This does not affect
   7960        the new generation Power and PowerPC architectures.
   7961      * Support has been removed for all the [4]configurations obsoleted in
   7962        GCC 4.4.
   7963      * Support has been removed for the protoize and unprotoize utilities,
   7964        obsoleted in GCC 4.4.
   7965      * Support has been removed for tuning for Itanium1 (Merced) variants.
   7966        Note that code tuned for Itanium2 should also run correctly on
   7967        Itanium1.
   7968      * GCC now generates unwind info also for epilogues. DWARF debuginfo
   7969        generated by GCC now uses more features of DWARF3 than before, and
   7970        also some DWARF4 features. GDB older than 7.0 is not able to handle
   7971        either of these, so to debug GCC 4.5 generated binaries or
   7972        libraries GDB 7.0 or later is needed. You can disable use of DWARF4
   7973        features with the -gdwarf-3 -gstrict-dwarf options, or use
   7974        -gdwarf-2 -gstrict-dwarf to restrict GCC to just DWARF2, but
   7975        epilogue unwind info is emitted unconditionally whenever unwind
   7976        info is emitted.
   7977      * On x86 targets, code containing floating-point calculations may run
   7978        significantly more slowly when compiled with GCC 4.5 in strict C99
   7979        conformance mode than they did with earlier GCC versions. This is
   7980        due to stricter standard conformance of the compiler and can be
   7981        avoided by using the option -fexcess-precision=fast; also see
   7982        [5]below.
   7983      * The function attribute noinline no longer prevents GCC from cloning
   7984        the function. A new attribute noclone has been introduced for this
   7985        purpose. Cloning a function means that it is duplicated and the new
   7986        copy is specialized for certain contexts (for example when a
   7987        parameter is a known constant).
   7988 
   7989 General Optimizer Improvements
   7990 
   7991      * The -save-temps now takes an optional argument. The -save-temps and
   7992        -save-temps=cwd switches write the temporary files in the current
   7993        working directory based on the original source file. The
   7994        -save-temps=obj switch will write files into the directory
   7995        specified with the -o option, and the intermediate filenames are
   7996        based on the output file. This will allow the user to get the
   7997        compiler intermediate files when doing parallel builds without two
   7998        builds of the same filename located in different directories from
   7999        interfering with each other.
   8000      * Debugging dumps are now created in the same directory as the object
   8001        file rather than in the current working directory. This allows the
   8002        user to get debugging dumps when doing parallel builds without two
   8003        builds of the same filename interfering with each other.
   8004      * GCC has been integrated with the MPC library. This allows GCC to
   8005        evaluate complex arithmetic at compile time [6]more accurately. It
   8006        also allows GCC to evaluate calls to complex built-in math
   8007        functions having constant arguments and replace them at compile
   8008        time with their mathematically equivalent results. In doing so, GCC
   8009        can generate correct results regardless of the math library
   8010        implementation or floating point precision of the host platform.
   8011        This also allows GCC to generate identical results regardless of
   8012        whether one compiles in native or cross-compile configurations to a
   8013        particular target. The following built-in functions take advantage
   8014        of this new capability: cacos, cacosh, casin, casinh, catan,
   8015        catanh, ccos, ccosh, cexp, clog, cpow, csin, csinh, csqrt, ctan,
   8016        and ctanh. The float and long double variants of these functions
   8017        (e.g. csinf and csinl) are also handled.
   8018      * A new link-time optimizer has been added ([7]-flto). When this
   8019        option is used, GCC generates a bytecode representation of each
   8020        input file and writes it to specially-named sections in each object
   8021        file. When the object files are linked together, all the function
   8022        bodies are read from these named sections and instantiated as if
   8023        they had been part of the same translation unit. This enables
   8024        interprocedural optimizations to work across different files (and
   8025        even different languages), potentially improving the performance of
   8026        the generated code. To use the link-timer optimizer, -flto needs to
   8027        be specified at compile time and during the final link. If the
   8028        program does not require any symbols to be exported, it is possible
   8029        to combine -flto and the experimental [8]-fwhopr with
   8030        [9]-fwhole-program to allow the interprocedural optimizers to use
   8031        more aggressive assumptions.
   8032      * The automatic parallelization pass was enhanced to support
   8033        parallelization of outer loops.
   8034      * Automatic parallelization can be enabled as part of Graphite. In
   8035        addition to -ftree-parallelize-loops=, specify
   8036        -floop-parallelize-all to enable the Graphite-based optimization.
   8037      * The infrastructure for optimizing based on [10]restrict qualified
   8038        pointers has been rewritten and should result in code generation
   8039        improvements. Optimizations based on restrict qualified pointers
   8040        are now also available when using -fno-strict-aliasing.
   8041      * There is a new optimization pass that attempts to change prototype
   8042        of functions to avoid unused parameters, pass only relevant parts
   8043        of structures and turn arguments passed by reference to arguments
   8044        passed by value when possible. It is enabled by -O2 and above as
   8045        well as -Os and can be manually invoked using the new command-line
   8046        switch -fipa-sra.
   8047      * GCC now optimize exception handling code. In particular cleanup
   8048        regions that are proved to not have any effect are optimized out.
   8049 
   8050 New Languages and Language specific improvements
   8051 
   8052   All languages
   8053 
   8054      * The -fshow-column option is now on by default. This means error
   8055        messages now have a column associated with them.
   8056 
   8057   Ada
   8058 
   8059      * Compilation of programs heavily using discriminated record types
   8060        with variant parts has been sped up and generates more compact
   8061        code.
   8062      * Stack checking now works reasonably well on most plaforms. In some
   8063        specific cases, stack overflows may still fail to be detected, but
   8064        a compile-time warning will be issued for these cases.
   8065 
   8066   C family
   8067 
   8068      * If a header named in a #include directive is not found, the
   8069        compiler exits immediately. This avoids a cascade of errors arising
   8070        from declarations expected to be found in that header being
   8071        missing.
   8072      * A new built-in function __builtin_unreachable() has been added that
   8073        tells the compiler that control will never reach that point. It may
   8074        be used after asm statements that terminate by transferring control
   8075        elsewhere, and in other places that are known to be unreachable.
   8076      * The -Wlogical-op option now warns for logical expressions such as
   8077        (c == 1 && c == 2) and (c != 1 || c != 2), which are likely to be
   8078        mistakes. This option is disabled by default.
   8079      * An asm goto feature has been added to allow asm statements that
   8080        jump to C labels.
   8081      * C++0x raw strings are supported for C++ and for C with -std=gnu99.
   8082      * The deprecated attribute now takes an optional string argument, for
   8083        example, __attribute__((deprecated("text string"))), that will be
   8084        printed together with the deprecation warning.
   8085 
   8086   C
   8087 
   8088      * The -Wenum-compare option, which warns when comparing values of
   8089        different enum types, now works for C. It formerly only worked for
   8090        C++. This warning is enabled by -Wall. It may be avoided by using a
   8091        type cast.
   8092      * The -Wcast-qual option now warns about casts which are unsafe in
   8093        that they permit const-correctness to be violated without further
   8094        warnings. Specifically, it warns about cases where a qualifier is
   8095        added when all the lower types are not const. For example, it warns
   8096        about a cast from char ** to const char **.
   8097      * The -Wc++-compat option is significantly improved. It issues new
   8098        warnings for:
   8099           + Using C++ reserved operator names as identifiers.
   8100           + Conversions to enum types without explicit casts.
   8101           + Using va_arg with an enum type.
   8102           + Using different enum types in the two branches of ?:.
   8103           + Using ++ or -- on a variable of enum type.
   8104           + Using the same name as both a struct, union or enum tag and a
   8105             typedef, unless the typedef refers to the tagged type itself.
   8106           + Using a struct, union, or enum which is defined within another
   8107             struct or union.
   8108           + A struct field defined using a typedef if there is a field in
   8109             the struct, or an enclosing struct, whose name is the typedef
   8110             name.
   8111           + Duplicate definitions at file scope.
   8112           + Uninitialized const variables.
   8113           + A global variable with an anonymous struct, union, or enum
   8114             type.
   8115           + Using a string constant to initialize a char array whose size
   8116             is the length of the string.
   8117      * The new -Wjump-misses-init option warns about cases where a goto or
   8118        switch skips the initialization of a variable. This sort of branch
   8119        is an error in C++ but not in C. This warning is enabled by
   8120        -Wc++-compat.
   8121      * GCC now ensures that a C99-conforming <stdint.h> is present on most
   8122        targets, and uses information about the types in this header to
   8123        implement the Fortran bindings to those types. GCC does not ensure
   8124        the presence of such a header, and does not implement the Fortran
   8125        bindings, on the following targets: NetBSD, VxWorks, VMS,
   8126        SymbianOS, WinCE, LynxOS, Netware, QNX, Interix, TPF.
   8127      * GCC now implements C90- and C99-conforming rules for constant
   8128        expressions. This may cause warnings or errors for some code using
   8129        expressions that can be folded to a constant but are not constant
   8130        expressions as defined by ISO C.
   8131      * All known target-independent C90 and C90 Amendment 1 conformance
   8132        bugs, and all known target-independent C99 conformance bugs not
   8133        related to floating point or extended identifiers, have been fixed.
   8134      * The C decimal floating point support now includes support for the
   8135        FLOAT_CONST_DECIMAL64 pragma.
   8136      * The named address space feature from ISO/IEC TR 18037 is now
   8137        supported. This is currently only implemented for the SPU
   8138        processor.
   8139 
   8140   C++
   8141 
   8142      * Improved [11]experimental support for the upcoming C++0x ISO C++
   8143        standard, including support for raw strings, lambda expressions and
   8144        explicit type conversion operators.
   8145      * When printing the name of a class template specialization, G++ will
   8146        now omit any template arguments which come from default template
   8147        arguments. This behavior (and the pretty-printing of function
   8148        template specializations as template signature and arguments) can
   8149        be disabled with the -fno-pretty-templates option.
   8150      * Access control is now applied to typedef names used in a template,
   8151        which may cause G++ to reject some ill-formed code that was
   8152        accepted by earlier releases. The -fno-access-control option can be
   8153        used as a temporary workaround until the code is corrected.
   8154      * Compilation time for code that uses templates should now scale
   8155        linearly with the number of instantiations rather than
   8156        quadratically, as template instantiations are now looked up using
   8157        hash tables.
   8158      * Declarations of functions that look like builtin declarations of
   8159        library functions are only considered to be redeclarations if they
   8160        are declared with extern "C". This may cause problems with code
   8161        that omits extern "C" on hand-written declarations of C library
   8162        functions such as abort or memcpy. Such code is ill-formed, but was
   8163        accepted by earlier releases.
   8164      * Diagnostics that used to complain about passing non-POD types to
   8165        ... or jumping past the declaration of a non-POD variable now check
   8166        for triviality rather than PODness, as per C++0x.
   8167      * In C++0x mode local and anonymous classes are now allowed as
   8168        template arguments, and in declarations of variables and functions
   8169        with linkage, so long as any such declaration that is used is also
   8170        defined ([12]DR 757).
   8171      * Labels may now have attributes, as has been permitted for a while
   8172        in C. This is only permitted when the label definition and the
   8173        attribute specifier is followed by a semicoloni.e., the label
   8174        applies to an empty statement. The only useful attribute for a
   8175        label is unused.
   8176      * G++ now implements [13]DR 176. Previously G++ did not support using
   8177        the injected-class-name of a template base class as a type name,
   8178        and lookup of the name found the declaration of the template in the
   8179        enclosing scope. Now lookup of the name finds the
   8180        injected-class-name, which can be used either as a type or as a
   8181        template, depending on whether or not the name is followed by a
   8182        template argument list. As a result of this change, some code that
   8183        was previously accepted may be ill-formed because
   8184          1. The injected-class-name is not accessible because it's from a
   8185             private base, or
   8186          2. The injected-class-name cannot be used as an argument for a
   8187             template template parameter.
   8188        In either of these cases, the code can be fixed by adding a
   8189        nested-name-specifier to explicitly name the template. The first
   8190        can be worked around with -fno-access-control; the second is only
   8191        rejected with -pedantic.
   8192      * A new standard mangling for SIMD vector types has been added, to
   8193        avoid name clashes on systems with vectors of varying length. By
   8194        default the compiler still uses the old mangling, but emits aliases
   8195        with the new mangling on targets that support strong aliases. Users
   8196        can switch over entirely to the new mangling with -fabi-version=4
   8197        or -fabi-version=0. -Wabi will now warn about code that uses the
   8198        old mangling.
   8199      * The command-line option -ftemplate-depth-N is now written as
   8200        -ftemplate-depth=N and the old form is deprecated.
   8201      * Conversions between NULL and non-pointer types are now warned by
   8202        default. The new option -Wno-conversion-null disables these
   8203        warnings. Previously these warnings were only available when using
   8204        -Wconversion explicitly.
   8205 
   8206     Runtime Library (libstdc++)
   8207 
   8208      * Improved experimental support for the upcoming ISO C++ standard,
   8209        C++0x, including:
   8210           + Support for <future>, <functional>, and <random>.
   8211           + Existing facilities now exploit explicit operators and the
   8212             newly implemented core C++0x features.
   8213           + The header <cstdatomic> has been renamed to <atomic>.
   8214      * An experimental [14]profile mode has been added. This is an
   8215        implementation of many C++ standard library constructs with an
   8216        additional analysis layer that gives performance improvement advice
   8217        based on recognition of suboptimal usage patterns. For example,
   8218 #include <vector>
   8219 int main()
   8220 {
   8221   std::vector<int> v;
   8222   for (int k = 0; k < 1024; ++k)
   8223     v.insert(v.begin(), k);
   8224 }
   8225 
   8226        When instrumented via the profile mode, can return suggestions
   8227        about the initial size and choice of the container used as follows:
   8228 vector-to-list: improvement = 5: call stack = 0x804842c ...
   8229     : advice = change std::vector to std::list
   8230 vector-size: improvement = 3: call stack = 0x804842c ...
   8231     : advice = change initial container size from 0 to 1024
   8232 
   8233        These constructs can be substituted for the normal libstdc++
   8234        constructs on a piecemeal basis, or all existing components can be
   8235        transformed via the -D_GLIBCXX_PROFILE macro.
   8236      * [15]Support for decimal floating-point arithmetic (aka ISO C++ TR
   8237        24733) has been added. This support is in header file
   8238        <decimal/decimal>, uses namespace std::decimal, and includes
   8239        classes decimal32, decimal64, and decimal128.
   8240      * Sources have been audited for application of function attributes
   8241        nothrow, const, pure, and noreturn.
   8242      * Python pretty-printers have been added for many standard library
   8243        components that simplify the internal representation and present a
   8244        more intuitive view of components when used with
   8245        appropriately-advanced versions of GDB. For more information,
   8246        please consult the more [16]detailed description.
   8247      * The default behavior for comparing typeinfo names has changed, so
   8248        in <typeinfo>, __GXX_MERGED_TYPEINFO_NAMES now defaults to zero.
   8249      * The new -static-libstdc++ option directs g++ to link the C++
   8250        library statically, even if the default would normally be to link
   8251        it dynamically.
   8252 
   8253   Fortran
   8254 
   8255      * The COMMON default padding has been changed  instead of adding the
   8256        padding before a variable it is now added afterwards, which
   8257        increases the compatibility with other vendors and helps to obtain
   8258        the correct output in some cases. Cf. also the -falign-commons
   8259        option ([17]added in 4.4).
   8260      * The -finit-real= option now also supports the value snan for
   8261        signaling not-a-number; to be effective, one additionally needs to
   8262        enable trapping (e.g. via -ffpe-trap=). Note: Compile-time
   8263        optimizations can turn a signaling NaN into a quiet one.
   8264      * The new option -fcheck= has been added with the options bounds,
   8265        array-temps, do, pointer, and recursive. The bounds and array-temps
   8266        options are equivalent to -fbounds-check and
   8267        -fcheck-array-temporaries. The do option checks for invalid
   8268        modification of loop iteration variables, and the recursive option
   8269        tests for recursive calls to subroutines/functions which are not
   8270        marked as recursive. With pointer pointer association checks in
   8271        calls are performed; however, neither undefined pointers nor
   8272        pointers in expressions are handled. Using -fcheck=all enables all
   8273        these run-time checks.
   8274      * The run-time checking -fcheck=bounds now warns about invalid string
   8275        lengths of character dummy arguments. Additionally, more
   8276        compile-time checks have been added.
   8277      * The new option [18]-fno-protect-parens has been added; if set, the
   8278        compiler may reorder REAL and COMPLEX expressions without regard to
   8279        parentheses.
   8280      * GNU Fortran no longer links against libgfortranbegin. As before,
   8281        MAIN__ (assembler symbol name) is the actual Fortran main program,
   8282        which is invoked by the main function. However, main is now
   8283        generated and put in the same object file as MAIN__. For the time
   8284        being, libgfortranbegin still exists for backward compatibility.
   8285        For details see the new [19]Mixed-Language Programming chapter in
   8286        the manual.
   8287      * The I/O library was restructured for performance and cleaner code.
   8288      * Array assignments and WHERE are now run in parallel when OpenMP's
   8289        WORKSHARE is used.
   8290      * The experimental option -fwhole-file was added. The option allows
   8291        whole-file checking of procedure arguments and allows for better
   8292        optimizations. It can also be used with -fwhole-program, which is
   8293        now also supported in gfortran.
   8294      * More Fortran 2003 and Fortran 2008 mathematical functions can now
   8295        be used as initialization expressions.
   8296      * Some extended attributes such as STDCALL are now supported via the
   8297        [20]GCC$ compiler directive.
   8298      * For Fortran 77 compatibility: If -fno-sign-zero is used, the SIGN
   8299        intrinsic behaves now as if zero were always positive.
   8300      * For legacy compatibiliy: On Cygwin and MinGW, the special files
   8301        CONOUT$ and CONIN$ (and CONERR$ which maps to CONOUT$) are now
   8302        supported.
   8303      * Fortran 2003 support has been extended:
   8304           + Procedure-pointer function results and procedure-pointer
   8305             components (including PASS),
   8306           + allocatable scalars (experimental),
   8307           + DEFERRED type-bound procedures,
   8308           + the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements
   8309             have been implemented.
   8310           + The ALLOCATE statement supports type-specs and the SOURCE=
   8311             argument.
   8312           + OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC
   8313             type-bound procedure (i.e. as type-bound operators).
   8314           + Rounding (ROUND=, RZ, ...) for output is now supported.
   8315           + The INT_FAST{8,16,32,64,128}_T kind type parameters of the
   8316             intrinsic module ISO_C_BINDING are now supported, except for
   8317             the targets listed above as ones where GCC does not have
   8318             <stdint.h> type information.
   8319           + Extensible derived types with type-bound procedure or
   8320             procedure pointer with PASS attribute now have to use CLASS in
   8321             line with the Fortran 2003 standard; the workaround to use
   8322             TYPE is no longer supported.
   8323           + [21]Experimental, incomplete support for polymorphism,
   8324             including CLASS, SELECT TYPE and dynamic dispatch of
   8325             type-bound procedure calls. Some features do not work yet such
   8326             as unlimited polymorphism (CLASS(*)).
   8327      * Fortran 2008 support has been extended:
   8328           + The OPEN statement now supports the NEWUNIT= option, which
   8329             returns a unique file unit, thus preventing inadvertent use of
   8330             the same unit in different parts of the program.
   8331           + Support for unlimited format items has been added.
   8332           + The INT{8,16,32} and REAL{32,64,128} kind type parameters of
   8333             the intrinsic module ISO_FORTRAN_ENV are now supported.
   8334           + Using complex arguments with TAN, SINH, COSH, TANH, ASIN,
   8335             ACOS, and ATAN is now possible; the functions ASINH, ACOSH,
   8336             and ATANH have been added (for real and complex arguments) and
   8337             ATAN(Y,X) is now an alias for ATAN2(Y,X).
   8338           + The BLOCK construct has been implemented.
   8339 
   8340 New Targets and Target Specific Improvements
   8341 
   8342   AIX
   8343 
   8344      * Full cross-toolchain support now available with GNU Binutils
   8345 
   8346   ARM
   8347 
   8348      * GCC now supports the Cortex-M0 and Cortex-A5 processors.
   8349      * GCC now supports the ARM v7E-M architecture.
   8350      * GCC now supports VFPv4-based FPUs and FPUs with
   8351        single-precision-only VFP.
   8352      * GCC has many improvements to optimization for other ARM processors,
   8353        including scheduling support for the integer pipeline on Cortex-A9.
   8354      * GCC now supports the IEEE 754-2008 half-precision floating-point
   8355        type, and a variant ARM-specific half-precision type. This type is
   8356        specified using __fp16, with the layout determined by
   8357        -mfp16-format. With appropriate -mfpu options, the Cortex-A9 and
   8358        VFPv4 half-precision instructions will be used.
   8359      * GCC now supports the variant of AAPCS that uses VFP registers for
   8360        parameter passing and return values.
   8361 
   8362   AVR
   8363 
   8364      * The -mno-tablejump option has been removed because it has the same
   8365        effect as the -fno-jump-tables option.
   8366      * Added support for these new AVR devices:
   8367           + ATmega8U2
   8368           + ATmega16U2
   8369           + ATmega32U2
   8370 
   8371   IA-32/x86-64
   8372 
   8373      * GCC now will set the default for -march= based on the configure
   8374        target.
   8375      * GCC now supports handling floating-point excess precision arising
   8376        from use of the x87 floating-point unit in a way that conforms to
   8377        ISO C99. This is enabled with -fexcess-precision=standard and with
   8378        standards conformance options such as -std=c99, and may be disabled
   8379        using -fexcess-precision=fast.
   8380      * Support for the Intel Atom processor is now available through the
   8381        -march=atom and -mtune=atom options.
   8382      * A new -mcrc32 option is now available to enable crc32 intrinsics.
   8383      * A new -mmovbe option is now available to enable GCC to use the
   8384        movbe instruction to implement __builtin_bswap32 and
   8385        __builtin_bswap64.
   8386      * SSE math now can be enabled by default at configure time with the
   8387        new --with-fpmath=sse option.
   8388      * There is a new intrinsic header file, <x86intrin.h>. It should be
   8389        included before using any IA-32/x86-64 intrinsics.
   8390      * Support for the XOP, FMA4, and LWP instruction sets for the AMD
   8391        Orochi processors are now available with the -mxop, -mfma4, and
   8392        -mlwp options.
   8393      * The -mabm option enables GCC to use the popcnt and lzcnt
   8394        instructions on AMD processors.
   8395      * The -mpopcnt option enables GCC to use the popcnt instructions on
   8396        both AMD and Intel processors.
   8397 
   8398   M68K/ColdFire
   8399 
   8400      * GCC now supports ColdFire 51xx, 5221x, 5225x, 52274, 52277, 5301x
   8401        and 5441x devices.
   8402      * GCC now supports thread-local storage (TLS) on M68K and ColdFire
   8403        processors.
   8404 
   8405   MeP
   8406 
   8407    Support has been added for the Toshiba Media embedded Processor (MeP,
   8408    or mep-elf) embedded target.
   8409 
   8410   MIPS
   8411 
   8412      * GCC now supports MIPS 1004K processors.
   8413      * GCC can now be configured with options --with-arch-32,
   8414        --with-arch-64, --with-tune-32 and --with-tune-64 to control the
   8415        default optimization separately for 32-bit and 64-bit modes.
   8416      * MIPS targets now support an alternative _mcount interface, in which
   8417        register $12 points to the function's save slot for register $31.
   8418        This interface is selected by the -mcount-ra-address option; see
   8419        the documentation for more details.
   8420      * GNU/Linux targets can now generate read-only .eh_frame sections.
   8421        This optimization requires GNU binutils 2.20 or above, and is only
   8422        available if GCC is configured with a suitable version of binutils.
   8423      * GNU/Linux targets can now attach special relocations to indirect
   8424        calls, so that the linker can turn them into direct jumps or
   8425        branches. This optimization requires GNU binutils 2.20 or later,
   8426        and is automatically selected if GCC is configured with an
   8427        appropriate version of binutils. It can be explicitly enabled or
   8428        disabled using the -mrelax-pic-calls command-line option.
   8429      * GCC now generates more heavily-optimized atomic operations on
   8430        Octeon processors.
   8431      * MIPS targets now support the -fstack-protector option.
   8432      * GCC now supports an -msynci option, which specifies that synci is
   8433        enough to flush the instruction cache, without help from the
   8434        operating system. GCC uses this information to optimize
   8435        automatically-generated cache flush operations, such as those used
   8436        for nested functions in C. There is also a --with-synci
   8437        configure-time option, which makes -msynci the default.
   8438      * GCC supports four new function attributes for interrupt handlers:
   8439        interrupt, use_shadow_register_set, keep_interrupts_masked and
   8440        use_debug_exception_return. See the documentation for more details
   8441        about these attributes.
   8442 
   8443   RS/6000 (POWER/PowerPC)
   8444 
   8445      * GCC now supports the Power ISA 2.06, which includes the VSX
   8446        instructions that add vector 64-bit floating point support, new
   8447        population count instructions, and conversions between floating
   8448        point and unsigned types.
   8449      * Support for the power7 processor is now available through the
   8450        -mcpu=power7 and -mtune=power7.
   8451      * GCC will now vectorize loops that contain simple math functions
   8452        like copysign when generating code for altivec or VSX targets.
   8453      * Support for the A2 processor is now available through the -mcpu=a2
   8454        and -mtune=a2 options.
   8455      * Support for the 476 processor is now available through the
   8456        -mcpu={476,476fp} and -mtune={476,476fp} options.
   8457      * Support for the e500mc64 processor is now available through the
   8458        -mcpu=e500mc64 and -mtune=e500mc64 options.
   8459      * GCC can now be configured with options --with-cpu-32,
   8460        --with-cpu-64, --with-tune-32 and --with-tune-64 to control the
   8461        default optimization separately for 32-bit and 64-bit modes.
   8462      * Starting with GCC 4.5.4, vectors of type vector long long or vector
   8463        long are passed and returned in the same method as other vectors
   8464        with the VSX instruction set. Previously the GCC compiler did not
   8465        adhere to the ABI for 128-bit vectors with 64-bit integer base
   8466        types (PR 48857). This is also fixed in the GCC 4.6.1 release.
   8467 
   8468   RX
   8469 
   8470    Support has been added for the Renesas RX Processor (rx-elf) target.
   8471 
   8472 Operating Systems
   8473 
   8474   Windows (Cygwin and MinGW)
   8475 
   8476      * GCC now installs all the major language runtime libraries as DLLs
   8477        when configured with the --enable-shared option.
   8478      * GCC now makes use of the new support for aligned common variables
   8479        in versions of binutils >= 2.20 to fix bugs in the support for SSE
   8480        data types.
   8481      * Improvements to the libffi support library increase the reliability
   8482        of code generated by GCJ on all Windows platforms. Libgcj is
   8483        enabled by default for the first time.
   8484      * Libtool improvements simplify installation by placing the generated
   8485        DLLs in the correct binaries directory.
   8486      * Numerous other minor bugfixes and improvements, and substantial
   8487        enhancements to the Fortran language support library.
   8488 
   8489    >
   8490 
   8491 Other significant improvements
   8492 
   8493   Plugins
   8494 
   8495      * It is now possible to extend the compiler without having to modify
   8496        its source code. A new option -fplugin=file.so tells GCC to load
   8497        the shared object file.so and execute it as part of the compiler.
   8498        The internal documentation describes the details on how plugins can
   8499        interact with the compiler.
   8500 
   8501   Installation changes
   8502 
   8503      * The move to newer autotools changed default installation
   8504        directories and switches to control them: The --with-datarootdir,
   8505        --with-docdir, --with-pdfdir, and --with-htmldir switches are not
   8506        used any more. Instead, you can now use --datarootdir, --docdir,
   8507        --htmldir, and --pdfdir. The default installation directories have
   8508        changed as follows according to the GNU Coding Standards:
   8509 
   8510        datarootdir read-only architecture-independent data root [PREFIX/share]
   8511        localedir   locale-specific message catalogs [DATAROOTDIR/locale]
   8512        docdir      documentation root [DATAROOTDIR/doc/PACKAGE]
   8513        htmldir     html documentation [DOCDIR]
   8514        dvidir      dvi documentation [DOCDIR]
   8515        pdfdir      pdf documentation [DOCDIR]
   8516        psdir       ps documentation [DOCDIR]
   8517        The following variables have new default values:
   8518 
   8519        datadir read-only architecture-independent data [DATAROOTDIR]
   8520        infodir info documentation [DATAROOTDIR/info]
   8521        mandir  man documentation [DATAROOTDIR/man]
   8522 
   8523 GCC 4.5.1
   8524 
   8525    This is the [22]list of problem reports (PRs) from GCC's bug tracking
   8526    system that are known to be fixed in the 4.5.1 release. This list might
   8527    not be complete (that is, it is possible that some PRs that have been
   8528    fixed are not listed here).
   8529 
   8530   All languages
   8531 
   8532      * GCC's new link-time optimizer ([23]-flto) now also works on a few
   8533        non-ELF targets:
   8534           + Cygwin (*-cygwin*)
   8535           + MinGW (*-mingw*)
   8536           + Darwin on x86-64 (x86_64-apple-darwin*)
   8537        LTO is not enabled by default for these targets. To enable LTO, you
   8538        should configure with the --enable-lto option.
   8539 
   8540 GCC 4.5.2
   8541 
   8542    This is the [24]list of problem reports (PRs) from GCC's bug tracking
   8543    system that are known to be fixed in the 4.5.2 release. This list might
   8544    not be complete (that is, it is possible that some PRs that have been
   8545    fixed are not listed here).
   8546 
   8547 GCC 4.5.3
   8548 
   8549    This is the [25]list of problem reports (PRs) from GCC's bug tracking
   8550    system that are known to be fixed in the 4.5.3 release. This list might
   8551    not be complete (that is, it is possible that some PRs that have been
   8552    fixed are not listed here).
   8553 
   8554    On the PowerPC compiler, the Altivec builtin functions vec_ld and
   8555    vec_st have been modified to generate the Altivec memory instructions
   8556    LVX and STVX, even if the -mvsx option is used. In the initial GCC 4.5
   8557    release, these builtin functions were changed to generate VSX memory
   8558    reference instructions instead of Altivec memory instructions, but
   8559    there are differences between the two instructions. If the VSX
   8560    instruction set is available, you can now use the new builtin functions
   8561    vec_vsx_ld and vec_vsx_st which always generates the VSX memory
   8562    instructions.
   8563 
   8564 GCC 4.5.4
   8565 
   8566    This is the [26]list of problem reports (PRs) from GCC's bug tracking
   8567    system that are known to be fixed in the 4.5.4 release. This list might
   8568    not be complete (that is, it is possible that some PRs that have been
   8569    fixed are not listed here).
   8570 
   8571 
   8572     For questions related to the use of GCC, please consult these web
   8573     pages and the [27]GCC manuals. If that fails, the
   8574     [28]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   8575     web pages and the development of GCC are welcome on our developer
   8576     list at [29]gcc (a] gcc.gnu.org. All of [30]our lists have public
   8577     archives.
   8578 
   8579    Copyright (C) [31]Free Software Foundation, Inc. Verbatim copying and
   8580    distribution of this entire article is permitted in any medium,
   8581    provided this notice is preserved.
   8582 
   8583    These pages are [32]maintained by the GCC team. Last modified
   8584    2019-11-28[33].
   8585 
   8586 References
   8587 
   8588    1. http://www.multiprecision.org/mpc/
   8589    2. https://gcc.gnu.org/install/prerequisites.html
   8590    3. https://gcc.gnu.org/ml/gcc/2010-01/msg00510.html
   8591    4. http://gcc.gnu.org/gcc-4.4/changes.html#obsoleted
   8592    5. http://gcc.gnu.org/gcc-4.5/changes.html#x86
   8593    6. https://gcc.gnu.org/PR30789
   8594    7. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801
   8595    8. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhopr-802
   8596    9. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhole-program-800
   8597   10. https://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html
   8598   11. http://gcc.gnu.org/gcc-4.5/cxx0x_status.html
   8599   12. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#757
   8600   13. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#176
   8601   14. https://gcc.gnu.org/onlinedocs/libstdc++/manual/profile_mode.html
   8602   15. https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.tr24733
   8603   16. https://sourceware.org/gdb/wiki/STLSupport
   8604   17. http://gcc.gnu.org/gcc-4.4/changes.html
   8605   18. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html
   8606   19. https://gcc.gnu.org/onlinedocs/gfortran/Mixed-Language-Programming.html
   8607   20. https://gcc.gnu.org/onlinedocs/gfortran/GNU-Fortran-Compiler-Directives.html
   8608   21. https://gcc.gnu.org/wiki/OOP
   8609   22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.1
   8610   23. https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801
   8611   24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.2
   8612   25. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.3
   8613   26. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.4
   8614   27. https://gcc.gnu.org/onlinedocs/
   8615   28. mailto:gcc-help (a] gcc.gnu.org
   8616   29. mailto:gcc (a] gcc.gnu.org
   8617   30. https://gcc.gnu.org/lists.html
   8618   31. https://www.fsf.org/
   8619   32. https://gcc.gnu.org/about.html
   8620   33. http://validator.w3.org/check/referer
   8621 ======================================================================
   8622 http://gcc.gnu.org/gcc-4.4/index.html
   8623                              GCC 4.4 Release Series
   8624 
   8625    This release series is no longer maintained.
   8626 
   8627    March 13, 2012
   8628 
   8629    The [1]GNU project and the GCC developers are pleased to announce the
   8630    release of GCC 4.4.7.
   8631 
   8632    This release is a bug-fix release, containing fixes for regressions in
   8633    GCC 4.4.6 relative to previous releases of GCC.
   8634 
   8635 Release History
   8636 
   8637    GCC 4.4.7
   8638           March 13, 2012 ([2]changes)
   8639 
   8640    GCC 4.4.6
   8641           April 16, 2011 ([3]changes)
   8642 
   8643    GCC 4.4.5
   8644           October 1, 2010 ([4]changes)
   8645 
   8646    GCC 4.4.4
   8647           April 29, 2010 ([5]changes)
   8648 
   8649    GCC 4.4.3
   8650           January 21, 2010 ([6]changes)
   8651 
   8652    GCC 4.4.2
   8653           October 15, 2009 ([7]changes)
   8654 
   8655    GCC 4.4.1
   8656           July 22, 2009 ([8]changes)
   8657 
   8658    GCC 4.4.0
   8659           April 21, 2009 ([9]changes)
   8660 
   8661 References and Acknowledgements
   8662 
   8663    GCC used to stand for the GNU C Compiler, but since the compiler
   8664    supports several other languages aside from C, it now stands for the
   8665    GNU Compiler Collection.
   8666 
   8667    A list of [10]successful builds is updated as new information becomes
   8668    available.
   8669 
   8670    The GCC developers would like to thank the numerous people that have
   8671    contributed new features, improvements, bug fixes, and other changes as
   8672    well as test results to GCC. This [11]amazing group of volunteers is
   8673    what makes GCC successful.
   8674 
   8675    For additional information about GCC please refer to the [12]GCC
   8676    project web site or contact the [13]GCC development mailing list.
   8677 
   8678    To obtain GCC please use [14]our mirror sites or [15]our version
   8679    control system.
   8680 
   8681 
   8682     For questions related to the use of GCC, please consult these web
   8683     pages and the [16]GCC manuals. If that fails, the
   8684     [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   8685     web pages and the development of GCC are welcome on our developer
   8686     list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public
   8687     archives.
   8688 
   8689    Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and
   8690    distribution of this entire article is permitted in any medium,
   8691    provided this notice is preserved.
   8692 
   8693    These pages are [21]maintained by the GCC team. Last modified
   8694    2020-01-14[22].
   8695 
   8696 References
   8697 
   8698    1. http://www.gnu.org/
   8699    2. http://gcc.gnu.org/gcc-4.4/changes.html
   8700    3. http://gcc.gnu.org/gcc-4.4/changes.html
   8701    4. http://gcc.gnu.org/gcc-4.4/changes.html
   8702    5. http://gcc.gnu.org/gcc-4.4/changes.html
   8703    6. http://gcc.gnu.org/gcc-4.4/changes.html
   8704    7. http://gcc.gnu.org/gcc-4.4/changes.html
   8705    8. http://gcc.gnu.org/gcc-4.4/changes.html
   8706    9. http://gcc.gnu.org/gcc-4.4/changes.html
   8707   10. http://gcc.gnu.org/gcc-4.4/buildstat.html
   8708   11. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   8709   12. http://gcc.gnu.org/index.html
   8710   13. mailto:gcc (a] gcc.gnu.org
   8711   14. http://gcc.gnu.org/mirrors.html
   8712   15. http://gcc.gnu.org/git.html
   8713   16. https://gcc.gnu.org/onlinedocs/
   8714   17. mailto:gcc-help (a] gcc.gnu.org
   8715   18. mailto:gcc (a] gcc.gnu.org
   8716   19. https://gcc.gnu.org/lists.html
   8717   20. https://www.fsf.org/
   8718   21. https://gcc.gnu.org/about.html
   8719   22. http://validator.w3.org/check/referer
   8720 ======================================================================
   8721 http://gcc.gnu.org/gcc-4.4/changes.html
   8722                              GCC 4.4 Release Series
   8723                         Changes, New Features, and Fixes
   8724 
   8725    The latest release in the 4.4 release series is [1]GCC 4.4.7.
   8726 
   8727 Caveats
   8728 
   8729      * __builtin_stdarg_start has been completely removed from GCC.
   8730        Support for <varargs.h> had been deprecated since GCC 4.0. Use
   8731        __builtin_va_start as a replacement.
   8732      * Some of the errors issued by the C++ front end that could be
   8733        downgraded to warnings in previous releases by using -fpermissive
   8734        are now warnings by default. They can be converted into errors by
   8735        using -pedantic-errors.
   8736      * Use of the cpp assertion extension will now emit a warning when
   8737        -Wdeprecated or -pedantic is used. This extension has been
   8738        deprecated for many years, but never warned about.
   8739      * Packed bit-fields of type char were not properly bit-packed on many
   8740        targets prior to GCC 4.4. On these targets, the fix in GCC 4.4
   8741        causes an ABI change. For example there is no longer a 4-bit
   8742        padding between field a and b in this structure:
   8743     struct foo
   8744     {
   8745       char a:4;
   8746       char b:8;
   8747     } __attribute__ ((packed));
   8748        There is a new warning to help identify fields that are affected:
   8749     foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4
   8750        The warning can be disabled with -Wno-packed-bitfield-compat.
   8751      * On ARM EABI targets, the C++ mangling of the va_list type has been
   8752        changed to conform to the current revision of the EABI. This does
   8753        not affect the libstdc++ library included with GCC.
   8754      * The SCOUNT and POS bits of the MIPS DSP control register are now
   8755        treated as global. Previous versions of GCC treated these fields as
   8756        call-clobbered instead.
   8757      * The MIPS port no longer recognizes the h asm constraint. It was
   8758        necessary to remove this constraint in order to avoid generating
   8759        unpredictable code sequences.
   8760        One of the main uses of the h constraint was to extract the high
   8761        part of a multiplication on 64-bit targets. For example:
   8762     asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y));
   8763        You can now achieve the same effect using 128-bit types:
   8764     typedef unsigned int uint128_t __attribute__((mode(TI)));
   8765     result = ((uint128_t) x * y) >> 64;
   8766        The second sequence is better in many ways. For example, if x and y
   8767        are constants, the compiler can perform the multiplication at
   8768        compile time. If x and y are not constants, the compiler can
   8769        schedule the runtime multiplication better than it can schedule an
   8770        asm statement.
   8771      * Support for a number of older systems and recently unmaintained or
   8772        untested target ports of GCC has been declared obsolete in GCC 4.4.
   8773        Unless there is activity to revive them, the next release of GCC
   8774        will have their sources permanently removed.
   8775        The following ports for individual systems on particular
   8776        architectures have been obsoleted:
   8777           + Generic a.out on IA32 and m68k (i[34567]86-*-aout*,
   8778             m68k-*-aout*)
   8779           + Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*,
   8780             armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*,
   8781             sh-*-*). This does not affect other more specific targets
   8782             using the COFF object format on those architectures, or the
   8783             more specific H8300 and SH targets (h8300-*-rtems*,
   8784             h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*,
   8785             sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks).
   8786           + 2BSD on PDP-11 (pdp11-*-bsd)
   8787           + AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*,
   8788             powerpc-ibm-aix4.[12]*)
   8789           + Tuning support for Itanium1 (Merced) variants. Note that code
   8790             tuned for Itanium2 should also run correctly on Itanium1.
   8791      * The protoize and unprotoize utilities have been obsoleted and will
   8792        be removed in GCC 4.5. These utilities have not been installed by
   8793        default since GCC 3.0.
   8794      * Support has been removed for all the [2]configurations obsoleted in
   8795        GCC 4.3.
   8796      * Unknown -Wno-* options are now silently ignored by GCC if no other
   8797        diagnostics are issued. If other diagnostics are issued, then GCC
   8798        warns about the unknown options.
   8799      * More information on porting to GCC 4.4 from previous versions of
   8800        GCC can be found in the [3]porting guide for this release.
   8801 
   8802 General Optimizer Improvements
   8803 
   8804      * A new command-line switch -findirect-inlining has been added. When
   8805        turned on it allows the inliner to also inline indirect calls that
   8806        are discovered to have known targets at compile time thanks to
   8807        previous inlining.
   8808      * A new command-line switch -ftree-switch-conversion has been added.
   8809        This new pass turns simple initializations of scalar variables in
   8810        switch statements into initializations from a static array, given
   8811        that all the values are known at compile time and the ratio between
   8812        the new array size and the original switch branches does not exceed
   8813        the parameter --param switch-conversion-max-branch-ratio (default
   8814        is eight).
   8815      * A new command-line switch -ftree-builtin-call-dce has been added.
   8816        This optimization eliminates unnecessary calls to certain builtin
   8817        functions when the return value is not used, in cases where the
   8818        calls can not be eliminated entirely because the function may set
   8819        errno. This optimization is on by default at -O2 and above.
   8820      * A new command-line switch -fconserve-stack directs the compiler to
   8821        minimize stack usage even if it makes the generated code slower.
   8822        This affects inlining decisions.
   8823      * When the assembler supports it, the compiler will now emit unwind
   8824        information using assembler .cfi directives. This makes it possible
   8825        to use such directives in inline assembler code. The new option
   8826        -fno-dwarf2-cfi-asm directs the compiler to not use .cfi
   8827        directives.
   8828      * The [4]Graphite branch has been merged. This merge has brought in a
   8829        new framework for loop optimizations based on a polyhedral
   8830        intermediate representation. These optimizations apply to all the
   8831        languages supported by GCC. The following new code transformations
   8832        are available in GCC 4.4:
   8833           + -floop-interchange performs loop interchange transformations
   8834             on loops. Interchanging two nested loops switches the inner
   8835             and outer loops. For example, given a loop like:
   8836           DO J = 1, M
   8837             DO I = 1, N
   8838               A(J, I) = A(J, I) * C
   8839             ENDDO
   8840           ENDDO
   8841 
   8842             loop interchange will transform the loop as if the user had
   8843             written:
   8844           DO I = 1, N
   8845             DO J = 1, M
   8846               A(J, I) = A(J, I) * C
   8847             ENDDO
   8848           ENDDO
   8849 
   8850             which can be beneficial when N is larger than the caches,
   8851             because in Fortran, the elements of an array are stored in
   8852             memory contiguously by column, and the original loop iterates
   8853             over rows, potentially creating at each access a cache miss.
   8854           + -floop-strip-mine performs loop strip mining transformations
   8855             on loops. Strip mining splits a loop into two nested loops.
   8856             The outer loop has strides equal to the strip size and the
   8857             inner loop has strides of the original loop within a strip.
   8858             For example, given a loop like:
   8859           DO I = 1, N
   8860             A(I) = A(I) + C
   8861           ENDDO
   8862 
   8863             loop strip mining will transform the loop as if the user had
   8864             written:
   8865           DO II = 1, N, 4
   8866             DO I = II, min (II + 3, N)
   8867               A(I) = A(I) + C
   8868             ENDDO
   8869           ENDDO
   8870 
   8871           + -floop-block performs loop blocking transformations on loops.
   8872             Blocking strip mines each loop in the loop nest such that the
   8873             memory accesses of the element loops fit inside caches. For
   8874             example, given a loop like:
   8875           DO I = 1, N
   8876             DO J = 1, M
   8877               A(J, I) = B(I) + C(J)
   8878             ENDDO
   8879           ENDDO
   8880 
   8881             loop blocking will transform the loop as if the user had
   8882             written:
   8883           DO II = 1, N, 64
   8884             DO JJ = 1, M, 64
   8885               DO I = II, min (II + 63, N)
   8886                 DO J = JJ, min (JJ + 63, M)
   8887                   A(J, I) = B(I) + C(J)
   8888                 ENDDO
   8889               ENDDO
   8890             ENDDO
   8891           ENDDO
   8892 
   8893             which can be beneficial when M is larger than the caches,
   8894             because the innermost loop will iterate over a smaller amount
   8895             of data that can be kept in the caches.
   8896      * A new register allocator has replaced the old one. It is called
   8897        integrated register allocator (IRA) because coalescing, register
   8898        live range splitting, and hard register preferencing are done
   8899        on-the-fly during coloring. It also has better integration with the
   8900        reload pass. IRA is a regional register allocator which uses modern
   8901        Chaitin-Briggs coloring instead of Chow's priority coloring used in
   8902        the old register allocator. More info about IRA internals and
   8903        options can be found in the GCC manuals.
   8904      * A new instruction scheduler and software pipeliner, based on the
   8905        selective scheduling approach, has been added. The new pass
   8906        performs instruction unification, register renaming, substitution
   8907        through register copies, and speculation during scheduling. The
   8908        software pipeliner is able to pipeline non-countable loops. The new
   8909        pass is targeted at scheduling-eager in-order platforms. In GCC 4.4
   8910        it is available for the Intel Itanium platform working by default
   8911        as the second scheduling pass (after register allocation) at the
   8912        -O3 optimization level.
   8913      * When using -fprofile-generate with a multi-threaded program, the
   8914        profile counts may be slightly wrong due to race conditions. The
   8915        new -fprofile-correction option directs the compiler to apply
   8916        heuristics to smooth out the inconsistencies. By default the
   8917        compiler will give an error message when it finds an inconsistent
   8918        profile.
   8919      * The new -fprofile-dir=PATH option permits setting the directory
   8920        where profile data files are stored when using -fprofile-generate
   8921        and friends, and the directory used when reading profile data files
   8922        using -fprofile-use and friends.
   8923 
   8924 New warning options
   8925 
   8926      * The new -Wframe-larger-than=NUMBER option directs GCC to emit a
   8927        warning if any stack frame is larger than NUMBER bytes. This may be
   8928        used to help ensure that code fits within a limited amount of stack
   8929        space.
   8930      * The command-line option -Wlarger-than-N is now written as
   8931        -Wlarger-than=N and the old form is deprecated.
   8932      * The new -Wno-mudflap option disables warnings about constructs
   8933        which can not be instrumented when using -fmudflap.
   8934 
   8935 New Languages and Language specific improvements
   8936 
   8937      * Version 3.0 of the OpenMP specification is now supported for the C,
   8938        C++, and Fortran compilers.
   8939      * New character data types, per [5]TR 19769: New character types in
   8940        C, are now supported for the C compiler in -std=gnu99 mode, as
   8941        __CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in
   8942        -std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too.
   8943 
   8944   C family
   8945 
   8946      * A new optimize attribute was added to allow programmers to change
   8947        the optimization level and particular optimization options for an
   8948        individual function. You can also change the optimization options
   8949        via the GCC optimize pragma for functions defined after the pragma.
   8950        The GCC push_options pragma and the GCC pop_options pragma allow
   8951        you temporarily save and restore the options used. The GCC
   8952        reset_options pragma restores the options to what was specified on
   8953        the command line.
   8954      * Uninitialized warnings do not require enabling optimization
   8955        anymore, that is, -Wuninitialized can be used together with -O0.
   8956        Nonetheless, the warnings given by -Wuninitialized will probably be
   8957        more accurate if optimization is enabled.
   8958      * -Wparentheses now warns about expressions such as (!x | y) and (!x
   8959        & y). Using explicit parentheses, such as in ((!x) | y), silences
   8960        this warning.
   8961      * -Wsequence-point now warns within if, while,do while and for
   8962        conditions, and within for begin/end expressions.
   8963      * A new option -dU is available to dump definitions of preprocessor
   8964        macros that are tested or expanded.
   8965 
   8966   C++
   8967 
   8968      * [6]Improved experimental support for the upcoming ISO C++ standard,
   8969        C++0x. Including support for auto, inline namespaces, generalized
   8970        initializer lists, defaulted and deleted functions, new character
   8971        types, and scoped enums.
   8972      * Those errors that may be downgraded to warnings to build legacy
   8973        code now mention -fpermissive when -fdiagnostics-show-option is
   8974        enabled.
   8975      * -Wconversion now warns if the result of a static_cast to enumeral
   8976        type is unspecified because the value is outside the range of the
   8977        enumeral type.
   8978      * -Wuninitialized now warns if a non-static reference or non-static
   8979        const member appears in a class without constructors.
   8980      * G++ now properly implements value-initialization, so objects with
   8981        an initializer of () and an implicitly defined default constructor
   8982        will be zero-initialized before the default constructor is called.
   8983 
   8984     Runtime Library (libstdc++)
   8985 
   8986      * Improved experimental support for the upcoming ISO C++ standard,
   8987        C++0x, including:
   8988           + Support for <chrono>, <condition_variable>, <cstdatomic>,
   8989             <forward_list>, <initializer_list>, <mutex>, <ratio>,
   8990             <system_error>, and <thread>.
   8991           + unique_ptr, <algorithm> additions, exception propagation, and
   8992             support for the new character types in <string> and <limits>.
   8993           + Existing facilities now exploit initializer lists, defaulted
   8994             and deleted functions, and the newly implemented core C++0x
   8995             features.
   8996           + Some standard containers are more efficient together with
   8997             stateful allocators, i.e., no allocator is constructed on the
   8998             fly at element construction time.
   8999      * Experimental support for non-standard pointer types in containers.
   9000      * The long standing libstdc++/30928 has been fixed for targets
   9001        running glibc 2.10 or later.
   9002      * As usual, many small and larger bug fixes, in particular quite a
   9003        few corner cases in <locale>.
   9004 
   9005   Fortran
   9006 
   9007      * GNU Fortran now employs libcpp directly instead of using cc1 as an
   9008        external preprocessor. The [7]-cpp option was added to allow manual
   9009        invocation of the preprocessor without relying on filename
   9010        extensions.
   9011      * The [8]-Warray-temporaries option warns about array temporaries
   9012        generated by the compiler, as an aid to optimization.
   9013      * The [9]-fcheck-array-temporaries option has been added, printing a
   9014        notification at run time, when an array temporary had to be created
   9015        for an function argument. Contrary to -Warray-temporaries the
   9016        warning is only printed if the array is noncontiguous.
   9017      * Improved generation of DWARF debugging symbols
   9018      * If using an intrinsic not part of the selected standard (via -std=
   9019        and -fall-intrinsics) gfortran will now treat it as if this
   9020        procedure were declared EXTERNAL and try to link to a user-supplied
   9021        procedure. -Wintrinsics-std will warn whenever this happens. The
   9022        now-useless option -Wnonstd-intrinsic was removed.
   9023      * The flag -falign-commons has been added to control the alignment of
   9024        variables in COMMON blocks, which is enabled by default in line
   9025        with previous GCC version. Using -fno-align-commons one can force
   9026        commons to be contiguous in memory as required by the Fortran
   9027        standard, however, this slows down the memory access. The option
   9028        -Walign-commons, which is enabled by default, warns when padding
   9029        bytes were added for alignment. The proper solution is to sort the
   9030        common objects by decreasing storage size, which avoids the
   9031        alignment problems.
   9032      * Fortran 2003 support has been extended:
   9033           + Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is
   9034             now supported (except internal reads from/writes to wide
   9035             strings). [10]-fbackslash now supports also \unnnn and
   9036             \Unnnnnnnn to enter Unicode characters.
   9037           + Asynchronous I/O (implemented as synchronous I/O) and the
   9038             decimal=, size=, sign=, pad=, blank=, and delim= specifiers
   9039             are now supported in I/O statements.
   9040           + Support for Fortran 2003 structure constructors and for array
   9041             constructor with typespec has been added.
   9042           + Procedure Pointers (but not yet as component in derived types
   9043             and as function results) are now supported.
   9044           + Abstract types, type extension, and type-bound procedures
   9045             (both PROCEDURE and GENERIC but not as operators). Note: As
   9046             CLASS/polymorphyic types are not implemented, type-bound
   9047             procedures with PASS accept as non-standard extension TYPE
   9048             arguments.
   9049      * Fortran 2008 support has been added:
   9050           + The -std=f2008 option and support for the file extensions
   9051             .f2008 and .F2008 has been added.
   9052           + The g0 format descriptor is now supported.
   9053           + The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH,
   9054             ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED
   9055             are now available (some of them existed as GNU extension
   9056             before). Note: The hyperbolic functions are not yet supporting
   9057             complex arguments and the three- argument version of BESSEL_*N
   9058             is not available.
   9059           + The bit intrinsics LEADZ and TRAILZ have been added.
   9060 
   9061   Java (GCJ)
   9062 
   9063   Ada
   9064 
   9065      * The Ada runtime now supports multilibs on many platforms including
   9066        x86_64, SPARC and PowerPC. Their build is enabled by default.
   9067 
   9068 New Targets and Target Specific Improvements
   9069 
   9070   ARM
   9071 
   9072      * GCC now supports optimizing for the Cortex-A9, Cortex-R4 and
   9073        Cortex-R4F processors and has many other improvements to
   9074        optimization for ARM processors.
   9075      * GCC now supports the VFPv3 variant with 16 double-precision
   9076        registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been
   9077        renamed to -mfpu=vfpv3.
   9078      * GCC now supports the -mfix-cortex-m3-ldrd option to work around an
   9079        erratum on Cortex-M3 processors.
   9080      * GCC now supports the __sync_* atomic operations for ARM EABI
   9081        GNU/Linux.
   9082      * The section anchors optimization is now enabled by default when
   9083        optimizing for ARM.
   9084      * GCC now uses a new EABI-compatible profiling interface for EABI
   9085        targets. This requires a function __gnu_mcount_nc, which is
   9086        provided by GNU libc versions 2.8 and later.
   9087 
   9088   AVR
   9089 
   9090      * The -mno-tablejump option has been deprecated because it has the
   9091        same effect as the -fno-jump-tables option.
   9092      * Added support for these new AVR devices:
   9093           + ATA6289
   9094           + ATtiny13A
   9095           + ATtiny87
   9096           + ATtiny167
   9097           + ATtiny327
   9098           + ATmega8C1
   9099           + ATmega16C1
   9100           + ATmega32C1
   9101           + ATmega8M1
   9102           + ATmega16M1
   9103           + ATmega32M1
   9104           + ATmega32U4
   9105           + ATmega16HVB
   9106           + ATmega4HVD
   9107           + ATmega8HVD
   9108           + ATmega64C1
   9109           + ATmega64M1
   9110           + ATmega16U4
   9111           + ATmega32U6
   9112           + ATmega128RFA1
   9113           + AT90PWM81
   9114           + AT90SCR100
   9115           + M3000F
   9116           + M3000S
   9117           + M3001B
   9118 
   9119   IA-32/x86-64
   9120 
   9121      * Support for Intel AES built-in functions and code generation is
   9122        available via -maes.
   9123      * Support for Intel PCLMUL built-in function and code generation is
   9124        available via -mpclmul.
   9125      * Support for Intel AVX built-in functions and code generation is
   9126        available via -mavx.
   9127      * Automatically align the stack for local variables with alignment
   9128        requirement.
   9129      * GCC can now utilize the SVML library for vectorizing calls to a set
   9130        of C99 functions if -mveclibabi=svml is specified and you link to
   9131        an SVML ABI compatible library.
   9132      * On x86-64, the ABI has been changed in the following cases to
   9133        conform to the x86-64 ABI:
   9134           + Passing/returning structures with flexible array member:
   9135   struct foo
   9136     {
   9137       int i;
   9138       int flex[];
   9139     };
   9140           + Passing/returning structures with complex float member:
   9141   struct foo
   9142     {
   9143       int i;
   9144       __complex__ float f;
   9145     };
   9146           + Passing/returning unions with long double member:
   9147   union foo
   9148     {
   9149       int x;
   9150       long double ld;
   9151     };
   9152        Code built with previous versions of GCC that uses any of these is
   9153        not compatible with code built with GCC 4.4.0 or later.
   9154      * A new target attribute was added to allow programmers to change the
   9155        target options like -msse2 or -march=k8 for an individual function.
   9156        You can also change the target options via the GCC target pragma
   9157        for functions defined after the pragma.
   9158      * GCC can now be configured with options --with-arch-32,
   9159        --with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and
   9160        --with-tune-64 to control the default optimization separately for
   9161        32-bit and 64-bit modes.
   9162 
   9163   IA-32/IA64
   9164 
   9165      * Support for __float128 (TFmode) IEEE quad type and corresponding
   9166        TCmode IEEE complex quad type is available via the soft-fp library
   9167        on IA-32/IA64 targets. This includes basic arithmetic operations
   9168        (addition, subtraction, negation, multiplication and division) on
   9169        __float128 real and TCmode complex values, the full set of IEEE
   9170        comparisons between __float128 values, conversions to and from
   9171        float, double and long double floating point types, as well as
   9172        conversions to and from signed or unsigned integer, signed or
   9173        unsigned long integer and signed or unsigned quad (TImode, IA64
   9174        only) integer types. Additionally, all operations generate the full
   9175        set of IEEE exceptions and support the full set of IEEE rounding
   9176        modes.
   9177 
   9178   M68K/ColdFire
   9179 
   9180      * GCC now supports instruction scheduling for ColdFire V1, V3 and V4
   9181        processors. (Scheduling support for ColdFire V2 processors was
   9182        added in GCC 4.3.)
   9183      * GCC now supports the -mxgot option to support programs requiring
   9184        many GOT entries on ColdFire.
   9185      * The m68k-*-linux-gnu target now builds multilibs by default.
   9186 
   9187   MIPS
   9188 
   9189      * MIPS Technologies have extended the original MIPS SVR4 ABI to
   9190        include support for procedure linkage tables (PLTs) and copy
   9191        relocations. These extensions allow GNU/Linux executables to use a
   9192        significantly more efficient code model than the one defined by the
   9193        original ABI.
   9194        GCC support for this code model is available via a new command-line
   9195        option, -mplt. There is also a new configure-time option,
   9196        --with-mips-plt, to make -mplt the default.
   9197        The new code model requires support from the assembler, the linker,
   9198        and the runtime C library. This support is available in binutils
   9199        2.19 and GLIBC 2.9.
   9200      * GCC can now generate MIPS16 code for 32-bit GNU/Linux executables
   9201        and 32-bit GNU/Linux shared libraries. This feature requires GNU
   9202        binutils 2.19 or above.
   9203      * Support for RMI's XLR processor is now available through the
   9204        -march=xlr and -mtune=xlr options.
   9205      * 64-bit targets can now perform 128-bit multiplications inline,
   9206        instead of relying on a libgcc function.
   9207      * Native GNU/Linux toolchains now support -march=native and
   9208        -mtune=native, which select the host processor.
   9209      * GCC now supports the R10K, R12K, R14K and R16K processors. The
   9210        canonical -march= and -mtune= names for these processors are
   9211        r10000, r12000, r14000 and r16000 respectively.
   9212      * GCC can now work around the side effects of speculative execution
   9213        on R10K processors. Please see the documentation of the
   9214        -mr10k-cache-barrier option for details.
   9215      * Support for the MIPS64 Release 2 instruction set has been added.
   9216        The option -march=mips64r2 enables generation of these
   9217        instructions.
   9218      * GCC now supports Cavium Networks' Octeon processor. This support is
   9219        available through the -march=octeon and -mtune=octeon options.
   9220      * GCC now supports STMicroelectronics' Loongson 2E/2F processors. The
   9221        canonical -march= and -mtune= names for these processors are
   9222        loongson2e and loongson2f.
   9223 
   9224   picochip
   9225 
   9226    Picochip is a 16-bit processor. A typical picoChip contains over 250
   9227    small cores, each with small amounts of memory. There are three
   9228    processor variants (STAN, MEM and CTRL) with different instruction sets
   9229    and memory configurations and they can be chosen using the -mae option.
   9230 
   9231    This port is intended to be a "C" only port.
   9232 
   9233   Power Architecture and PowerPC
   9234 
   9235      * GCC now supports the e300c2, e300c3 and e500mc processors.
   9236      * GCC now supports Xilinx processors with a single-precision FPU.
   9237      * Decimal floating point is now supported for e500 processors.
   9238 
   9239   S/390, zSeries and System z9/z10
   9240 
   9241      * Support for the IBM System z10 EC/BC processor has been added. When
   9242        using the -march=z10 option, the compiler will generate code making
   9243        use of instructions provided by the General-Instruction-Extension
   9244        Facility and the Execute-Extension Facility.
   9245 
   9246   VxWorks
   9247 
   9248      * GCC now supports the thread-local storage mechanism used on
   9249        VxWorks.
   9250 
   9251   Xtensa
   9252 
   9253      * GCC now supports thread-local storage (TLS) for Xtensa processor
   9254        configurations that include the Thread Pointer option. TLS also
   9255        requires support from the assembler and linker; this support is
   9256        provided in the GNU binutils beginning with version 2.19.
   9257 
   9258 Documentation improvements
   9259 
   9260 Other significant improvements
   9261 
   9262 GCC 4.4.1
   9263 
   9264    This is the [11]list of problem reports (PRs) from GCC's bug tracking
   9265    system that are known to be fixed in the 4.4.1 release. This list might
   9266    not be complete (that is, it is possible that some PRs that have been
   9267    fixed are not listed here).
   9268 
   9269 GCC 4.4.2
   9270 
   9271    This is the [12]list of problem reports (PRs) from GCC's bug tracking
   9272    system that are known to be fixed in the 4.4.2 release. This list might
   9273    not be complete (that is, it is possible that some PRs that have been
   9274    fixed are not listed here).
   9275 
   9276 GCC 4.4.3
   9277 
   9278    This is the [13]list of problem reports (PRs) from GCC's bug tracking
   9279    system that are known to be fixed in the 4.4.3 release. This list might
   9280    not be complete (that is, it is possible that some PRs that have been
   9281    fixed are not listed here).
   9282 
   9283 GCC 4.4.4
   9284 
   9285    This is the [14]list of problem reports (PRs) from GCC's bug tracking
   9286    system that are known to be fixed in the 4.4.4 release. This list might
   9287    not be complete (that is, it is possible that some PRs that have been
   9288    fixed are not listed here).
   9289 
   9290 GCC 4.4.5
   9291 
   9292    This is the [15]list of problem reports (PRs) from GCC's bug tracking
   9293    system that are known to be fixed in the 4.4.5 release. This list might
   9294    not be complete (that is, it is possible that some PRs that have been
   9295    fixed are not listed here).
   9296 
   9297 GCC 4.4.6
   9298 
   9299    This is the [16]list of problem reports (PRs) from GCC's bug tracking
   9300    system that are known to be fixed in the 4.4.6 release. This list might
   9301    not be complete (that is, it is possible that some PRs that have been
   9302    fixed are not listed here).
   9303 
   9304 GCC 4.4.7
   9305 
   9306    This is the [17]list of problem reports (PRs) from GCC's bug tracking
   9307    system that are known to be fixed in the 4.4.7 release. This list might
   9308    not be complete (that is, it is possible that some PRs that have been
   9309    fixed are not listed here).
   9310 
   9311 
   9312     For questions related to the use of GCC, please consult these web
   9313     pages and the [18]GCC manuals. If that fails, the
   9314     [19]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   9315     web pages and the development of GCC are welcome on our developer
   9316     list at [20]gcc (a] gcc.gnu.org. All of [21]our lists have public
   9317     archives.
   9318 
   9319    Copyright (C) [22]Free Software Foundation, Inc. Verbatim copying and
   9320    distribution of this entire article is permitted in any medium,
   9321    provided this notice is preserved.
   9322 
   9323    These pages are [23]maintained by the GCC team. Last modified
   9324    2019-11-28[24].
   9325 
   9326 References
   9327 
   9328    1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.7
   9329    2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted
   9330    3. http://gcc.gnu.org/gcc-4.4/porting_to.html
   9331    4. https://gcc.gnu.org/wiki/Graphite
   9332    5. http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf
   9333    6. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html
   9334    7. https://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html
   9335    8. https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125
   9336    9. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221
   9337   10. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34
   9338   11. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1
   9339   12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2
   9340   13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3
   9341   14. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4
   9342   15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.5
   9343   16. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.6
   9344   17. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.7
   9345   18. https://gcc.gnu.org/onlinedocs/
   9346   19. mailto:gcc-help (a] gcc.gnu.org
   9347   20. mailto:gcc (a] gcc.gnu.org
   9348   21. https://gcc.gnu.org/lists.html
   9349   22. https://www.fsf.org/
   9350   23. https://gcc.gnu.org/about.html
   9351   24. http://validator.w3.org/check/referer
   9352 ======================================================================
   9353 http://gcc.gnu.org/gcc-4.3/index.html
   9354                              GCC 4.3 Release Series
   9355 
   9356    (This release series is no longer supported.)
   9357 
   9358    Jun 27, 2011
   9359 
   9360    The [1]GNU project and the GCC developers are pleased to announce the
   9361    release of GCC 4.3.6.
   9362 
   9363    This release is a bug-fix release, containing fixes for regressions in
   9364    GCC 4.3.5 relative to previous releases of GCC.
   9365 
   9366 Release History
   9367 
   9368    GCC 4.3.6
   9369           Jun 27, 2011 ([2]changes)
   9370 
   9371    GCC 4.3.5
   9372           May 22, 2010 ([3]changes)
   9373 
   9374    GCC 4.3.4
   9375           August 4, 2009 ([4]changes)
   9376 
   9377    GCC 4.3.3
   9378           January 24, 2009 ([5]changes)
   9379 
   9380    GCC 4.3.2
   9381           August 27, 2008 ([6]changes)
   9382 
   9383    GCC 4.3.1
   9384           June 6, 2008 ([7]changes)
   9385 
   9386    GCC 4.3.0
   9387           March 5, 2008 ([8]changes)
   9388 
   9389 References and Acknowledgements
   9390 
   9391    GCC used to stand for the GNU C Compiler, but since the compiler
   9392    supports several other languages aside from C, it now stands for the
   9393    GNU Compiler Collection.
   9394 
   9395    A list of [9]successful builds is updated as new information becomes
   9396    available.
   9397 
   9398    The GCC developers would like to thank the numerous people that have
   9399    contributed new features, improvements, bug fixes, and other changes as
   9400    well as test results to GCC. This [10]amazing group of volunteers is
   9401    what makes GCC successful.
   9402 
   9403    For additional information about GCC please refer to the [11]GCC
   9404    project web site or contact the [12]GCC development mailing list.
   9405 
   9406    To obtain GCC please use [13]our mirror sites or [14]our version
   9407    control system.
   9408 
   9409 
   9410     For questions related to the use of GCC, please consult these web
   9411     pages and the [15]GCC manuals. If that fails, the
   9412     [16]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   9413     web pages and the development of GCC are welcome on our developer
   9414     list at [17]gcc (a] gcc.gnu.org. All of [18]our lists have public
   9415     archives.
   9416 
   9417    Copyright (C) [19]Free Software Foundation, Inc. Verbatim copying and
   9418    distribution of this entire article is permitted in any medium,
   9419    provided this notice is preserved.
   9420 
   9421    These pages are [20]maintained by the GCC team. Last modified
   9422    2020-01-14[21].
   9423 
   9424 References
   9425 
   9426    1. http://www.gnu.org/
   9427    2. http://gcc.gnu.org/gcc-4.3/changes.html
   9428    3. http://gcc.gnu.org/gcc-4.3/changes.html
   9429    4. http://gcc.gnu.org/gcc-4.3/changes.html
   9430    5. http://gcc.gnu.org/gcc-4.3/changes.html
   9431    6. http://gcc.gnu.org/gcc-4.3/changes.html
   9432    7. http://gcc.gnu.org/gcc-4.3/changes.html
   9433    8. http://gcc.gnu.org/gcc-4.3/changes.html
   9434    9. http://gcc.gnu.org/gcc-4.3/buildstat.html
   9435   10. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   9436   11. http://gcc.gnu.org/index.html
   9437   12. mailto:gcc (a] gcc.gnu.org
   9438   13. http://gcc.gnu.org/mirrors.html
   9439   14. http://gcc.gnu.org/git.html
   9440   15. https://gcc.gnu.org/onlinedocs/
   9441   16. mailto:gcc-help (a] gcc.gnu.org
   9442   17. mailto:gcc (a] gcc.gnu.org
   9443   18. https://gcc.gnu.org/lists.html
   9444   19. https://www.fsf.org/
   9445   20. https://gcc.gnu.org/about.html
   9446   21. http://validator.w3.org/check/referer
   9447 ======================================================================
   9448 http://gcc.gnu.org/gcc-4.3/changes.html
   9449                              GCC 4.3 Release Series
   9450                         Changes, New Features, and Fixes
   9451 
   9452    The latest release in the 4.3 release series is [1]GCC 4.3.5.
   9453 
   9454 Caveats
   9455 
   9456      * GCC requires the [2]GMP and [3]MPFR libraries for building all the
   9457        various front-end languages it supports. See the [4]prerequisites
   9458        page for version requirements.
   9459      * ColdFire targets now treat long double as having the same format as
   9460        double. In earlier versions of GCC, they used the 68881 long double
   9461        format instead.
   9462      * The m68k-uclinux target now uses the same calling conventions as
   9463        m68k-linux-gnu. You can select the original calling conventions by
   9464        configuring for m68k-uclinuxoldabi instead. Note that
   9465        m68k-uclinuxoldabi also retains the original 80-bit long double on
   9466        ColdFire targets.
   9467      * The -fforce-mem option has been removed because it has had no
   9468        effect in the last few GCC releases.
   9469      * The i386 -msvr3-shlib option has been removed since it is no longer
   9470        used.
   9471      * Fastcall for i386 has been changed not to pass aggregate arguments
   9472        in registers, following Microsoft compilers.
   9473      * Support for the AOF assembler has been removed from the ARM back
   9474        end; this affects only the targets arm-semi-aof and armel-semi-aof,
   9475        which are no longer recognized. We removed these targets without a
   9476        deprecation period because we discovered that they have been
   9477        unusable since GCC 4.0.0.
   9478      * Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*)
   9479        has been removed. This support had been deprecated since GCC 4.0.0.
   9480      * Support for a number of older systems and recently unmaintained or
   9481        untested target ports of GCC has been declared obsolete in GCC 4.3.
   9482        Unless there is activity to revive them, the next release of GCC
   9483        will have their sources permanently removed.
   9484        All GCC ports for the following processor architectures have been
   9485        declared obsolete:
   9486           + Morpho MT (mt-*)
   9487        The following aliases for processor architectures have been
   9488        declared obsolete. Users should use the indicated generic target
   9489        names instead, with compile-time options such as -mcpu or
   9490        configure-time options such as --with-cpu to control the
   9491        configuration more precisely.
   9492           + strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-*
   9493             instead).
   9494           + parisc*-*-* (use hppa*-*-* instead).
   9495           + m680[012]0-*-* (use m68k-*-* instead).
   9496        All GCC ports for the following operating systems have been
   9497        declared obsolete:
   9498           + BeOS (*-*-beos*)
   9499           + kaOS (*-*-kaos*)
   9500           + GNU/Linux using the a.out object format (*-*-linux*aout*)
   9501           + GNU/Linux using version 1 of the GNU C Library
   9502             (*-*-linux*libc1*)
   9503           + Solaris versions before Solaris 7 (*-*-solaris2.[0-6],
   9504             *-*-solaris2.[0-6].*)
   9505           + Miscellaneous System V (*-*-sysv*)
   9506           + WindISS (*-*-windiss*)
   9507        Also, those for some individual systems on particular architectures
   9508        have been obsoleted:
   9509           + UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*)
   9510           + CRIS with a.out object format (cris-*-aout)
   9511           + BSD 4.3 on PA-RISC (hppa1.1-*-bsd*)
   9512           + OSF/1 on PA-RISC (hppa1.1-*-osf*)
   9513           + PRO on PA-RISC (hppa1.1-*-pro*)
   9514           + Sequent PTX on IA32 (i[34567]86-sequent-ptx4*,
   9515             i[34567]86-sequent-sysv4*)
   9516           + SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*)
   9517           + UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host
   9518             was previously [5]removed in 2001, leaving only the support
   9519             for UWIN as a target now being deprecated)
   9520           + ChorusOS on PowerPC (powerpc-*-chorusos*)
   9521           + All VAX configurations apart from NetBSD and OpenBSD
   9522             (vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*)
   9523      * The [6]-Wconversion option has been modified. Its purpose now is to
   9524        warn for implicit conversions that may alter a value. This new
   9525        behavior is available for both C and C++. Warnings about
   9526        conversions between signed and unsigned integers can be disabled by
   9527        using -Wno-sign-conversion. In C++, they are disabled by default
   9528        unless -Wsign-conversion is explicitly requested. The old behavior
   9529        of -Wconversion, that is, warn for prototypes causing a type
   9530        conversion that is different from what would happen to the same
   9531        argument in the absence of a prototype, has been moved to a new
   9532        option -Wtraditional-conversion, which is only available for C.
   9533      * The -m386, -m486, -mpentium and -mpentiumpro tuning options have
   9534        been removed because they were deprecated for more than 3 GCC major
   9535        releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or
   9536        -mtune=pentiumpro as a replacement.
   9537      * The -funsafe-math-optimizations option now automatically turns on
   9538        -fno-trapping-math in addition to -fno-signed-zeros, as it enables
   9539        reassociation and thus may introduce or remove traps.
   9540      * The -ftree-vectorize option is now on by default under -O3. In
   9541        order to generate code for a SIMD extension, it has to be enabled
   9542        as well: use -maltivec for PowerPC platforms and -msse/-msse2 for
   9543        i?86 and x86_64.
   9544      * More information on porting to GCC 4.3 from previous versions of
   9545        GCC can be found in the [7]porting guide for this release.
   9546 
   9547 General Optimizer Improvements
   9548 
   9549      * The GCC middle-end has been integrated with the MPFR library. This
   9550        allows GCC to evaluate and replace at compile-time calls to
   9551        built-in math functions having constant arguments with their
   9552        mathematically equivalent results. In making use of MPFR, GCC can
   9553        generate correct results regardless of the math library
   9554        implementation or floating point precision of the host platform.
   9555        This also allows GCC to generate identical results regardless of
   9556        whether one compiles in native or cross-compile configurations to a
   9557        particular target. The following built-in functions take advantage
   9558        of this new capability: acos, acosh, asin, asinh, atan2, atan,
   9559        atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1,
   9560        fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10,
   9561        log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh,
   9562        tan, tanh, tgamma, y0, y1 and yn. The float and long double
   9563        variants of these functions (e.g. sinf and sinl) are also handled.
   9564        The sqrt and cabs functions with constant arguments were already
   9565        optimized in prior GCC releases. Now they also use MPFR.
   9566      * A new forward propagation pass on RTL was added. The new pass
   9567        replaces several slower transformations, resulting in compile-time
   9568        improvements as well as better code generation in some cases.
   9569      * A new command-line switch -frecord-gcc-switches has been added to
   9570        GCC, although it is only enabled for some targets. The switch
   9571        causes the command line that was used to invoke the compiler to be
   9572        recorded into the object file that is being created. The exact
   9573        format of this recording is target and binary file format
   9574        dependent, but it usually takes the form of a note section
   9575        containing ASCII text. The switch is related to the -fverbose-asm
   9576        switch, but that one only records the information in the assembler
   9577        output file as comments, so the information never reaches the
   9578        object file.
   9579      * The inliner heuristic is now aware of stack frame consumption. New
   9580        command-line parameters --param large-stack-frame and --param
   9581        large-stack-frame-growth can be used to limit stack frame size
   9582        growth caused by inlining.
   9583      * During feedback directed optimizations, the expected block size the
   9584        memcpy, memset and bzero functions operate on is discovered and for
   9585        cases of commonly used small sizes, specialized inline code is
   9586        generated.
   9587      * __builtin_expect no longer requires its argument to be a compile
   9588        time constant.
   9589      * Interprocedural optimization was reorganized to work on functions
   9590        in SSA form. This enables more precise and cheaper dataflow
   9591        analysis and makes writing interprocedural optimizations easier.
   9592        The following improvements have been implemented on top of this
   9593        framework:
   9594           + Pre-inline optimization: Selected local optimization passes
   9595             are run before the inliner (and other interprocedural passes)
   9596             are executed. This significantly improves the accuracy of code
   9597             growth estimates used by the inliner and reduces the overall
   9598             memory footprint for large compilation units.
   9599           + Early inlining (a simple bottom-up inliner pass inlining only
   9600             functions whose body is smaller than the expected call
   9601             overhead) is now executed with the early optimization passes,
   9602             thus inlining already optimized function bodies into an
   9603             unoptimized function that is subsequently optimized by early
   9604             optimizers. This enables the compiler to quickly eliminate
   9605             abstraction penalty in C++ programs.
   9606           + Interprocedural constant propagation now operate on SSA form
   9607             increasing accuracy of the analysis.
   9608      * A new internal representation for GIMPLE statements has been
   9609        contributed, resulting in compile-time memory savings.
   9610      * The vectorizer was enhanced to support vectorization of outer
   9611        loops, intra-iteration parallelism (loop-aware SLP), vectorization
   9612        of strided accesses and loops with multiple data-types. Run-time
   9613        dependency testing using loop versioning was added. The cost model,
   9614        turned on by -fvect-cost-model, was developed.
   9615 
   9616 New Languages and Language specific improvements
   9617 
   9618      * We have added new command-line options
   9619        -finstrument-functions-exclude-function-list and
   9620        -finstrument-functions-exclude-file-list. They provide more control
   9621        over which functions are annotated by the -finstrument-functions
   9622        option.
   9623 
   9624   C family
   9625 
   9626      * Implicit conversions between generic vector types are now only
   9627        permitted when the two vectors in question have the same number of
   9628        elements and compatible element types. (Note that the restriction
   9629        involves compatible element types, not implicitly-convertible
   9630        element types: thus, a vector type with element type int may not be
   9631        implicitly converted to a vector type with element type unsigned
   9632        int.) This restriction, which is in line with specifications for
   9633        SIMD architectures such as AltiVec, may be relaxed using the flag
   9634        -flax-vector-conversions. This flag is intended only as a
   9635        compatibility measure and should not be used for new code.
   9636      * -Warray-bounds has been added and is now enabled by default for
   9637        -Wall . It produces warnings for array subscripts that can be
   9638        determined at compile time to be always out of bounds.
   9639        -Wno-array-bounds will disable the warning.
   9640      * The constructor and destructor function attributes now accept
   9641        optional priority arguments which control the order in which the
   9642        constructor and destructor functions are run.
   9643      * New [8]command-line options -Wtype-limits, -Wold-style-declaration,
   9644        -Wmissing-parameter-type, -Wempty-body, -Wclobbered and
   9645        -Wignored-qualifiers have been added for finer control of the
   9646        diverse warnings enabled by -Wextra.
   9647      * A new function attribute alloc_size has been added to mark up
   9648        malloc style functions. For constant sized allocations this can be
   9649        used to find out the size of the returned pointer using the
   9650        __builtin_object_size() function for buffer overflow checking and
   9651        similar. This supplements the already built-in malloc and calloc
   9652        constant size handling.
   9653      * Integer constants written in binary are now supported as a GCC
   9654        extension. They consist of a prefix 0b or 0B, followed by a
   9655        sequence of 0 and 1 digits.
   9656      * A new predefined macro __COUNTER__ has been added. It expands to
   9657        sequential integral values starting from 0. In conjunction with the
   9658        ## operator, this provides a convenient means to generate unique
   9659        identifiers.
   9660      * A new command-line option -fdirectives-only has been added. It
   9661        enables a special preprocessing mode which improves the performance
   9662        of applications like distcc and ccache.
   9663      * Fixed-point data types and operators have been added. They are
   9664        based on Chapter 4 of the Embedded-C specification (n1169.pdf).
   9665        Currently, only MIPS targets are supported.
   9666      * Decimal floating-point arithmetic based on draft ISO/IEC TR 24732,
   9667        N1241, is now supported as a GCC extension to C for targets
   9668        i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu,
   9669        and x86_64-*-linux-gnu. The feature introduces new data types
   9670        _Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF,
   9671        DD, and DL.
   9672 
   9673   C++
   9674 
   9675      * [9]Experimental support for the upcoming ISO C++ standard, C++0x.
   9676      * -Wc++0x-compat has been added and is now enabled by default for
   9677        -Wall. It produces warnings for constructs whose meaning differs
   9678        between ISO C++ 1998 and C++0x.
   9679      * The -Wparentheses option now works for C++ as it does for C. It
   9680        warns if parentheses are omitted when operators with confusing
   9681        precedence are nested. It also warns about ambiguous else
   9682        statements. Since -Wparentheses is enabled by -Wall, this may cause
   9683        additional warnings with existing C++ code which uses -Wall. These
   9684        new warnings may be disabled by using -Wall -Wno-parentheses.
   9685      * The -Wmissing-declarations now works for C++ as it does for C.
   9686      * The -fvisibility-ms-compat flag was added, to make it easier to
   9687        port larger projects using shared libraries from Microsoft's Visual
   9688        Studio to ELF and Mach-O systems.
   9689      * C++ attribute handling has been overhauled for template arguments
   9690        (ie dependent types). In particular, __attribute__((aligned(T)));
   9691        works for C++ types.
   9692 
   9693     Runtime Library (libstdc++)
   9694 
   9695      * [10]Experimental support for the upcoming ISO C++ standard, C++0x.
   9696      * Support for TR1 mathematical special functions and regular
   9697        expressions.
   9698      * Default what implementations give more elaborate exception strings
   9699        for bad_cast, bad_typeid, bad_exception, and bad_alloc.
   9700      * Header dependencies have been streamlined, reducing unnecessary
   9701        includes and pre-processed bloat.
   9702      * Variadic template implementations of items in <tuple> and
   9703        <functional>.
   9704      * An experimental [11]parallel mode has been added. This is a
   9705        parallel implementation of many C++ Standard library algorithms,
   9706        like std::accumulate, std::for_each, std::transform, or std::sort,
   9707        to give but four examples. These algorithms can be substituted for
   9708        the normal (sequential) libstdc++ algorithms on a piecemeal basis,
   9709        or all existing algorithms can be transformed via the
   9710        -D_GLIBCXX_PARALLEL macro.
   9711      * Debug mode versions of classes in <unordered_set> and
   9712        <unordered_map>.
   9713      * Formal deprecation of <ext/hash_set> and <ext/hash_map>, which are
   9714        now <backward/hash_set> and <backward/hash_map>. This code:
   9715     #include <ext/hash_set>
   9716     __gnu_cxx::hash_set<int> s;
   9717 
   9718        Can be transformed (in order of preference) to:
   9719     #include <tr1/unordered_set>
   9720     std::tr1::unordered_set<int> s;
   9721 
   9722        or
   9723     #include <backward/hash_set>
   9724     __gnu_cxx::hash_set<int> s;
   9725 
   9726        Similar transformations apply to __gnu_cxx::hash_map,
   9727        __gnu_cxx::hash_multimap, __gnu_cxx::hash_set,
   9728        __gnu_cxx::hash_multiset.
   9729 
   9730   Fortran
   9731 
   9732      * Due to the fact that the GMP and MPFR libraries are required for
   9733        all languages, Fortran is no longer special in this regard and is
   9734        available by default.
   9735      * The [12]-fexternal-blas option has been added, which generates
   9736        calls to BLAS routines for intrinsic matrix operations such as
   9737        matmul rather than using the built-in algorithms.
   9738      * Support to give a backtrace (compiler flag -fbacktrace or
   9739        environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems
   9740        only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a
   9741        run-time error occured.
   9742      * GNU Fortran now defines __GFORTRAN__ when it runs the C
   9743        preprocessor (CPP).
   9744      * The [13]-finit-local-zero, -finit-real, -finit-integer,
   9745        -finit-character, and -finit-logical options have been added, which
   9746        can be used to initialize local variables.
   9747      * The intrinsic procedures [14]GAMMA and [15]LGAMMA have been added,
   9748        which calculate the Gamma function and its logarithm. Use EXTERNAL
   9749        gamma if you want to use your own gamma function.
   9750      * GNU Fortran now regards the backslash character as literal (as
   9751        required by the Fortran 2003 standard); using [16]-fbackslash GNU
   9752        Fortran interprets backslashes as C-style escape characters.
   9753      * The [17]interpretation of binary, octal and hexadecimal (BOZ)
   9754        literal constants has been changed. Before they were always
   9755        interpreted as integer; now they are bit-wise transferred as
   9756        argument of INT, REAL, DBLE and CMPLX as required by the Fortran
   9757        2003 standard, and for real and complex variables in DATA
   9758        statements or when directly assigned to real and complex variables.
   9759        Everywhere else and especially in expressions they are still
   9760        regarded as integer constants.
   9761      * Fortran 2003 support has been extended:
   9762           + Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE
   9763           + Pointer intent
   9764           + Intrinsic module ISO_ENV_FORTRAN
   9765           + Interoperability with C (ISO C Bindings)
   9766           + ABSTRACT INTERFACES and PROCEDURE statements (without POINTER
   9767             attribute)
   9768           + Fortran 2003 BOZ
   9769 
   9770   Java (GCJ)
   9771 
   9772      * GCJ now uses the Eclipse Java compiler for its Java parsing needs.
   9773        This enables the use of all 1.5 language features, and fixes most
   9774        existing front end bugs.
   9775      * libgcj now supports all 1.5 language features which require runtime
   9776        support: foreach, enum, annotations, generics, and auto-boxing.
   9777      * We've made many changes to the tools shipped with gcj.
   9778           + The old jv-scan tool has been removed. This tool never really
   9779             worked properly. There is no replacement.
   9780           + gcjh has been rewritten. Some of its more obscure options no
   9781             longer work, but are still recognized in an attempt at
   9782             compatibility. gjavah is a new program with similar
   9783             functionality but different command-line options.
   9784           + grmic and grmiregistry have been rewritten. grmid has been
   9785             added.
   9786           + gjar replaces the old fastjar.
   9787           + gjarsigner (used for signing jars), gkeytool (used for key
   9788             management), gorbd (for CORBA), gserialver (computes
   9789             serialization UIDs), and gtnameserv (also for CORBA) are now
   9790             installed.
   9791      * The ability to dump the contents of the java run time heap to a
   9792        file for off-line analysis has been added. The heap dumps may be
   9793        analyzed with the new gc-analyze tool. They may be generated on
   9794        out-of-memory conditions or on demand and are controlled by the new
   9795        run time class gnu.gcj.util.GCInfo.
   9796      * java.util.TimeZone can now read files from /usr/share/zoneinfo to
   9797        provide correct, updated, timezone information. This means that
   9798        packagers no longer have to update libgcj when a time zone change
   9799        is published.
   9800 
   9801 New Targets and Target Specific Improvements
   9802 
   9803   IA-32/x86-64
   9804 
   9805      * Tuning for Intel Core 2 processors is available via -mtune=core2
   9806        and -march=core2.
   9807      * Tuning for AMD Geode processors is available via -mtune=geode and
   9808        -march=geode.
   9809      * Code generation of block move (memcpy) and block set (memset) was
   9810        rewritten. GCC can now pick the best algorithm (loop, unrolled
   9811        loop, instruction with rep prefix or a library call) based on the
   9812        size of the block being copied and the CPU being optimized for. A
   9813        new option -minline-stringops-dynamically has been added. With this
   9814        option string operations of unknown size are expanded such that
   9815        small blocks are copied by in-line code, while for large blocks a
   9816        library call is used. This results in faster code than
   9817        -minline-all-stringops when the library implementation is capable
   9818        of using cache hierarchy hints. The heuristic choosing the
   9819        particular algorithm can be overwritten via -mstringop-strategy.
   9820        Newly also memset of values different from 0 is inlined.
   9821      * GCC no longer places the cld instruction before string operations.
   9822        Both i386 and x86-64 ABI documents mandate the direction flag to be
   9823        clear at the entry of a function. It is now invalid to set the flag
   9824        in asm statement without reseting it afterward.
   9825      * Support for SSSE3 built-in functions and code generation are
   9826        available via -mssse3.
   9827      * Support for SSE4.1 built-in functions and code generation are
   9828        available via -msse4.1.
   9829      * Support for SSE4.2 built-in functions and code generation are
   9830        available via -msse4.2.
   9831      * Both SSE4.1 and SSE4.2 support can be enabled via -msse4.
   9832      * A new set of options -mpc32, -mpc64 and -mpc80 have been added to
   9833        allow explicit control of x87 floating point precision.
   9834      * Support for __float128 (TFmode) IEEE quad type and corresponding
   9835        TCmode IEEE complex quad type is available via the soft-fp library
   9836        on x86_64 targets. This includes basic arithmetic operations
   9837        (addition, subtraction, negation, multiplication and division) on
   9838        __float128 real and TCmode complex values, the full set of IEEE
   9839        comparisons between __float128 values, conversions to and from
   9840        float, double and long double floating point types, as well as
   9841        conversions to and from signed or unsigned integer, signed or
   9842        unsigned long integer and signed or unsigned quad (TImode) integer
   9843        types. Additionally, all operations generate the full set of IEEE
   9844        exceptions and support the full set of IEEE rounding modes.
   9845      * GCC can now utilize the ACML library for vectorizing calls to a set
   9846        of C99 functions on x86_64 if -mveclibabi=acml is specified and you
   9847        link to an ACML ABI compatible library.
   9848 
   9849   ARM
   9850 
   9851      * Compiler and Library support for Thumb-2 and the ARMv7 architecture
   9852        has been added.
   9853 
   9854   CRIS
   9855 
   9856     New features
   9857 
   9858      * Compiler and Library support for the CRIS v32 architecture, as
   9859        found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been
   9860        added.
   9861 
   9862     Configuration changes
   9863 
   9864      * The cris-*-elf target now includes support for CRIS v32, including
   9865        libraries, through the -march=v32 option.
   9866      * A new crisv32-*-elf target defaults to generate code for CRIS v32.
   9867      * A new crisv32-*-linux* target defaults to generate code for CRIS
   9868        v32.
   9869      * The cris-*-aout target has been obsoleted.
   9870 
   9871     Improved support for built-in functions
   9872 
   9873      * GCC can now use the lz and swapwbr instructions to implement the
   9874        __builtin_clz, __builtin_ctz and __builtin_ffs family of functions.
   9875      * __builtin_bswap32 is now implemented using the swapwb instruction,
   9876        when available.
   9877 
   9878   m68k and ColdFire
   9879 
   9880     New features
   9881 
   9882      * Support for several new ColdFire processors has been added. You can
   9883        generate code for them using the new -mcpu option.
   9884      * All targets now support ColdFire processors.
   9885      * m68k-uclinux targets have improved support for C++ constructors and
   9886        destructors, and for shared libraries.
   9887      * It is now possible to set breakpoints on the first or last line of
   9888        a function, even if there are no statements on that line.
   9889 
   9890     Optimizations
   9891 
   9892      * Support for sibling calls has been added.
   9893      * More use is now made of the ColdFire mov3q instruction.
   9894      * __builtin_clz is now implemented using the ff1 ColdFire
   9895        instruction, when available.
   9896      * GCC now honors the -m68010 option. 68010 code now uses clr rather
   9897        than move to zero volatile memory.
   9898      * 68020 targets and above can now use symbol(index.size*scale)
   9899        addresses for indexed array accesses. Earlier compilers would
   9900        always load the symbol into a base register first.
   9901 
   9902     Configuration changes
   9903 
   9904      * All m68k and ColdFire targets now allow the default processor to be
   9905        set at configure time using --with-cpu.
   9906      * A --with-arch configuration option has been added. This option
   9907        allows you to restrict a target to ColdFire or non-ColdFire
   9908        processors.
   9909 
   9910     Preprocessor macros
   9911 
   9912      * An __mcfv*__ macro is now defined for all ColdFire targets.
   9913        (Earlier versions of GCC only defined __mcfv4e__.)
   9914      * __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added.
   9915      * All targets now define __mc68010 and __mc68010__ when generating
   9916        68010 code.
   9917 
   9918     Command-line changes
   9919 
   9920      * New command-line options -march, -mcpu, -mtune and -mhard-float
   9921        have been added. These options apply to both m68k and ColdFire
   9922        targets.
   9923      * -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative
   9924        versions of -mshort, etc.
   9925      * -fforce-addr has been removed. It is now ignored by the compiler.
   9926 
   9927     Other improvements
   9928 
   9929      * ColdFire targets now try to maintain a 4-byte-aligned stack where
   9930        possible.
   9931      * m68k-uclinux targets now try to avoid situations that lead to the
   9932        load-time error: BINFMT_FLAT: reloc outside program.
   9933 
   9934   MIPS
   9935 
   9936     Changes to existing configurations
   9937 
   9938      * libffi and libjava now support all three GNU/Linux ABIs: o32, n32
   9939        and n64. Every GNU/Linux configuration now builds these libraries
   9940        by default.
   9941      * GNU/Linux configurations now generate -mno-shared code unless
   9942        overridden by -fpic, -fPIC, -fpie or -fPIE.
   9943      * mipsisa32*-linux-gnu configurations now generate hard-float code by
   9944        default, just like other mipsisa32* and mips*-linux-gnu
   9945        configurations. You can build a soft-float version of any
   9946        mips*-linux-gnu configuration by passing --with-float=soft to
   9947        configure.
   9948      * mips-wrs-vxworks now supports run-time processes (RTPs).
   9949 
   9950     Changes to existing command-line options
   9951 
   9952      * The -march and -mtune options no longer accept 24k as a processor
   9953        name. Please use 24kc, 24kf2_1 or 24kf1_1 instead.
   9954      * The -march and -mtune options now accept 24kf2_1, 24kef2_1 and
   9955        34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The
   9956        options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for
   9957        24kx, 24kex and 34kx.
   9958 
   9959     New configurations
   9960 
   9961    GCC now supports the following configurations:
   9962      * mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by
   9963        default. Earlier releases also recognized this configuration, but
   9964        they treated it in the same way as mipsisa32*-linux-gnu*. Note that
   9965        you can customize any mips*-linux-gnu* configuration to a
   9966        particular ISA or processor by passing an appropriate --with-arch
   9967        option to configure.
   9968      * mipsisa*-sde-elf*, which provides compatibility with MIPS
   9969        Technologies' SDE toolchains. The configuration uses the SDE
   9970        libraries by default, but you can use it like other newlib-based
   9971        ELF configurations by passing --with-newlib to configure. It is the
   9972        only configuration besides mips64vr*-elf* to build MIPS16 as well
   9973        as non-MIPS16 libraries.
   9974      * mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf*
   9975        configuration, but uses the o32 and o64 ABIs instead of the 32-bit
   9976        and 64-bit forms of the EABI.
   9977 
   9978     New processors and application-specific extensions
   9979 
   9980      * Support for the SmartMIPS ASE is available through the new
   9981        -msmartmips option.
   9982      * Support for revision 2 of the DSP ASE is available through the new
   9983        -mdspr2 option. A new preprocessor macro called __mips_dsp_rev
   9984        indicates the revision of the ASE in use.
   9985      * Support for the 4KS and 74K families of processors is available
   9986        through the -march and -mtune options.
   9987 
   9988     Improved support for built-in functions
   9989 
   9990      * GCC can now use load-linked, store-conditional and sync
   9991        instructions to implement atomic built-in functions such as
   9992        __sync_fetch_and_add. The memory reference must be 4 bytes wide for
   9993        32-bit targets and either 4 or 8 bytes wide for 64-bit targets.
   9994      * GCC can now use the clz and dclz instructions to implement the
   9995        __builtin_ctz and __builtin_ffs families of functions.
   9996      * There is a new __builtin___clear_cache function for flushing the
   9997        instruction cache. GCC expands this function inline on MIPS32
   9998        revision 2 targets, otherwise it calls the function specified by
   9999        -mcache-flush-func.
   10000 
   10001     MIPS16 improvements
   10002 
   10003      * GCC can now compile objects that contain a mixture of MIPS16 and
   10004        non-MIPS16 code. There are two new attributes, mips16 and nomips16,
   10005        for specifying which mode a function should use.
   10006      * A new option called -minterlink-mips16 makes non-MIPS16 code
   10007        link-compatible with MIPS16 code.
   10008      * After many bug fixes, the long-standing MIPS16 -mhard-float support
   10009        should now work fairly reliably.
   10010      * GCC can now use the MIPS16e save and restore instructions.
   10011      * -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled
   10012        with -G0 -fsection-anchors is often smaller than code compiled with
   10013        -G8. However, please note that you must usually compile all objects
   10014        in your application with the same -G option; see the documentation
   10015        of -G for details.
   10016      * A new option called-mcode-readable specifies which instructions are
   10017        allowed to load from the code segment. -mcode-readable=yes is the
   10018        default and says that any instruction may load from the code
   10019        segment. The other alternatives are -mcode-readable=pcrel, which
   10020        says that only PC-relative MIPS16 instructions may load from the
   10021        code segment, and -mcode-readable=no, which says that no
   10022        instruction may do so. Please see the documentation for more
   10023        details, including example uses.
   10024 
   10025     Small-data improvements
   10026 
   10027    There are three new options for controlling small data:
   10028      * -mno-extern-sdata, which disables small-data accesses for
   10029        externally-defined variables. Code compiled with -Gn
   10030        -mno-extern-sdata will be link-compatible with any -G setting
   10031        between -G0 and -Gn inclusive.
   10032      * -mno-local-sdata, which disables the use of small-data sections for
   10033        data that is not externally visible. This option can be a useful
   10034        way of reducing small-data usage in less performance-critical parts
   10035        of an application.
   10036      * -mno-gpopt, which disables the use of the $gp register while still
   10037        honoring the -G limit when placing externally-visible data. This
   10038        option implies -mno-extern-sdata and -mno-local-sdata and it can be
   10039        useful in situations where $gp does not necessarily hold the
   10040        expected value.
   10041 
   10042     Miscellaneous improvements
   10043 
   10044      * There is a new option called -mbranch-cost for tweaking the
   10045        perceived cost of branches.
   10046      * If GCC is configured to use a version of GAS that supports the
   10047        .gnu_attribute directive, it will use that directive to record
   10048        certain properties of the output code. .gnu_attribute is new to GAS
   10049        2.18.
   10050      * There are two new function attributes, near and far, for overriding
   10051        the command-line setting of -mlong-calls on a function-by-function
   10052        basis.
   10053      * -mfp64, which previously required a 64-bit target, now works with
   10054        MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and
   10055        mipsisa*-sde-elf* configurations provide suitable library support.
   10056      * GCC now recognizes the -mdmx and -mmt options and passes them down
   10057        to the assembler. It does nothing else with the options at present.
   10058 
   10059   SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture
   10060   (BEA)
   10061 
   10062      * Support has been added for this new architecture.
   10063 
   10064   RS6000 (POWER/PowerPC)
   10065 
   10066      * Support for the PowerPC 750CL paired-single instructions has been
   10067        added with a new powerpc-*-linux*paired* target configuration. It
   10068        is enabled by an associated -mpaired option and can be accessed
   10069        using new built-in functions.
   10070      * Support for auto-detecting architecture and system configuration to
   10071        auto-select processor optimization tuning.
   10072      * Support for VMX on AIX 5.3 has been added.
   10073      * Support for AIX Version 6.1 has been added.
   10074 
   10075   S/390, zSeries and System z9
   10076 
   10077      * Support for the IBM System z9 EC/BC processor (z9 GA3) has been
   10078        added. When using the -march=z9-ec option, the compiler will
   10079        generate code making use of instructions provided by the decimal
   10080        floating point facility and the floating point conversion facility
   10081        (pfpo). Besides the instructions used to implement decimal floating
   10082        point operations these facilities also contain instructions to move
   10083        between general purpose and floating point registers and to modify
   10084        and copy the sign-bit of floating point values.
   10085      * When the -march=z9-ec option is used the new
   10086        -mhard-dfp/-mno-hard-dfp options can be used to specify whether the
   10087        decimal floating point hardware instructions will be used or not.
   10088        If none of them is given the hardware support is enabled by
   10089        default.
   10090      * The -mstack-guard option can now be omitted when using stack
   10091        checking via -mstack-size in order to let GCC choose a sensible
   10092        stack guard value according to the frame size of each function.
   10093      * Various changes to improve performance of generated code have been
   10094        implemented, including:
   10095           + The condition code set by an add logical with carry
   10096             instruction is now available for overflow checks like: a + b +
   10097             carry < b.
   10098           + The test data class instruction is now used to implement
   10099             sign-bit and infinity checks of binary and decimal floating
   10100             point numbers.
   10101 
   10102   SPARC
   10103 
   10104      * Support for the Sun UltraSPARC T2 (Niagara 2) processor has been
   10105        added.
   10106 
   10107   Xtensa
   10108 
   10109      * Stack unwinding for exception handling now uses by default a
   10110        specialized version of DWARF unwinding. This is not
   10111        binary-compatible with the setjmp/longjmp (sjlj) unwinding used for
   10112        Xtensa with previous versions of GCC.
   10113      * For Xtensa processors that include the Conditional Store option,
   10114        the built-in functions for atomic memory access are now implemented
   10115        using S32C1I instructions.
   10116      * If the Xtensa NSA option is available, GCC will use it to implement
   10117        the __builtin_ctz and __builtin_clz functions.
   10118 
   10119 Documentation improvements
   10120 
   10121      * Existing libstdc++ documentation has been edited and restructured
   10122        into a single DocBook XML manual. The results can be viewed online
   10123        [18]here.
   10124 
   10125 Other significant improvements
   10126 
   10127      * The compiler's --help command-line option has been extended so that
   10128        it now takes an optional set of arguments. These arguments restrict
   10129        the information displayed to specific classes of command-line
   10130        options, and possibly only a subset of those options. It is also
   10131        now possible to replace the descriptive text associated with each
   10132        displayed option with an indication of its current value, or for
   10133        binary options, whether it has been enabled or disabled.
   10134        Here are some examples. The following will display all the options
   10135        controlling warning messages:
   10136       --help=warnings
   10137 
   10138        Whereas this will display all the undocumented, target specific
   10139        options:
   10140       --help=target,undocumented
   10141 
   10142        This sequence of commands will display the binary optimizations
   10143        that are enabled by -O3:
   10144       gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
   10145       gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
   10146       diff /tmp/O2-opts /tmp/O3-opts | grep enabled
   10147 
   10148      * The configure options --with-pkgversion and --with-bugurl have been
   10149        added. These allow distributors of GCC to include a
   10150        distributor-specific string in manuals and --version output and to
   10151        specify the URL for reporting bugs in their versions of GCC.
   10152 
   10153 GCC 4.3.1
   10154 
   10155    This is the [19]list of problem reports (PRs) from GCC's bug tracking
   10156    system that are known to be fixed in the 4.3.1 release. This list might
   10157    not be complete (that is, it is possible that some PRs that have been
   10158    fixed are not listed here).
   10159 
   10160 Target Specific Changes
   10161 
   10162   IA-32/x86-64
   10163 
   10164     ABI changes
   10165 
   10166      * Starting with GCC 4.3.1, decimal floating point variables are
   10167        aligned to their natural boundaries when they are passed on the
   10168        stack for i386.
   10169 
   10170     Command-line changes
   10171 
   10172      * Starting with GCC 4.3.1, the -mcld option has been added to
   10173        automatically generate a cld instruction in the prologue of
   10174        functions that use string instructions. This option is used for
   10175        backward compatibility on some operating systems and can be enabled
   10176        by default for 32-bit x86 targets by configuring GCC with the
   10177        --enable-cld configure option.
   10178 
   10179 GCC 4.3.2
   10180 
   10181    This is the [20]list of problem reports (PRs) from GCC's bug tracking
   10182    system that are known to be fixed in the 4.3.2 release. This list might
   10183    not be complete (that is, it is possible that some PRs that have been
   10184    fixed are not listed here).
   10185 
   10186 GCC 4.3.3
   10187 
   10188    This is the [21]list of problem reports (PRs) from GCC's bug tracking
   10189    system that are known to be fixed in the 4.3.3 release. This list might
   10190    not be complete (that is, it is possible that some PRs that have been
   10191    fixed are not listed here).
   10192 
   10193 GCC 4.3.4
   10194 
   10195    This is the [22]list of problem reports (PRs) from GCC's bug tracking
   10196    system that are known to be fixed in the 4.3.4 release. This list might
   10197    not be complete (that is, it is possible that some PRs that have been
   10198    fixed are not listed here).
   10199 
   10200 GCC 4.3.5
   10201 
   10202    This is the [23]list of problem reports (PRs) from GCC's bug tracking
   10203    system that are known to be fixed in the 4.3.5 release. This list might
   10204    not be complete (that is, it is possible that some PRs that have been
   10205    fixed are not listed here).
   10206 
   10207 GCC 4.3.6
   10208 
   10209    This is the [24]list of problem reports (PRs) from GCC's bug tracking
   10210    system that are known to be fixed in the 4.3.6 release. This list might
   10211    not be complete (that is, it is possible that some PRs that have been
   10212    fixed are not listed here).
   10213 
   10214 
   10215     For questions related to the use of GCC, please consult these web
   10216     pages and the [25]GCC manuals. If that fails, the
   10217     [26]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   10218     web pages and the development of GCC are welcome on our developer
   10219     list at [27]gcc (a] gcc.gnu.org. All of [28]our lists have public
   10220     archives.
   10221 
   10222    Copyright (C) [29]Free Software Foundation, Inc. Verbatim copying and
   10223    distribution of this entire article is permitted in any medium,
   10224    provided this notice is preserved.
   10225 
   10226    These pages are [30]maintained by the GCC team. Last modified
   10227    2019-11-28[31].
   10228 
   10229 References
   10230 
   10231    1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.5
   10232    2. https://gmplib.org/
   10233    3. https://www.mpfr.org/
   10234    4. https://gcc.gnu.org/install/prerequisites.html
   10235    5. https://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html
   10236    6. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options
   10237    7. http://gcc.gnu.org/gcc-4.3/porting_to.html
   10238    8. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
   10239    9. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
   10240   10. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
   10241   11. https://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html
   10242   12. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options
   10243   13. https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167
   10244   14. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html
   10245   15. https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html
   10246   16. https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html
   10247   17. https://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html
   10248   18. https://gcc.gnu.org/onlinedocs/libstdc++/
   10249   19. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1
   10250   20. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2
   10251   21. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3
   10252   22. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4
   10253   23. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.5
   10254   24. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.6
   10255   25. https://gcc.gnu.org/onlinedocs/
   10256   26. mailto:gcc-help (a] gcc.gnu.org
   10257   27. mailto:gcc (a] gcc.gnu.org
   10258   28. https://gcc.gnu.org/lists.html
   10259   29. https://www.fsf.org/
   10260   30. https://gcc.gnu.org/about.html
   10261   31. http://validator.w3.org/check/referer
   10262 ======================================================================
   10263 http://gcc.gnu.org/gcc-4.2/index.html
   10264                              GCC 4.2 Release Series
   10265 
   10266    (This release series is no longer supported.)
   10267 
   10268    May 19, 2008
   10269 
   10270    The [1]GNU project and the GCC developers are pleased to announce the
   10271    release of GCC 4.2.4.
   10272 
   10273    This release is a bug-fix release, containing fixes for regressions in
   10274    GCC 4.2.3 relative to previous releases of GCC.
   10275 
   10276 Release History
   10277 
   10278    GCC 4.2.4
   10279           May 19, 2008 ([2]changes)
   10280 
   10281    GCC 4.2.3
   10282           February 1, 2008 ([3]changes)
   10283 
   10284    GCC 4.2.2
   10285           October 7, 2007 ([4]changes)
   10286 
   10287    GCC 4.2.1
   10288           July 18, 2007 ([5]changes)
   10289 
   10290    GCC 4.2.0
   10291           May 13, 2007 ([6]changes)
   10292 
   10293 References and Acknowledgements
   10294 
   10295    GCC used to stand for the GNU C Compiler, but since the compiler
   10296    supports several other languages aside from C, it now stands for the
   10297    GNU Compiler Collection.
   10298 
   10299    A list of [7]successful builds is updated as new information becomes
   10300    available.
   10301 
   10302    The GCC developers would like to thank the numerous people that have
   10303    contributed new features, improvements, bug fixes, and other changes as
   10304    well as test results to GCC. This [8]amazing group of volunteers is
   10305    what makes GCC successful.
   10306 
   10307    For additional information about GCC please refer to the [9]GCC project
   10308    web site or contact the [10]GCC development mailing list.
   10309 
   10310    To obtain GCC please use [11]our mirror sites or [12]our version
   10311    control system.
   10312 
   10313 
   10314     For questions related to the use of GCC, please consult these web
   10315     pages and the [13]GCC manuals. If that fails, the
   10316     [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   10317     web pages and the development of GCC are welcome on our developer
   10318     list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public
   10319     archives.
   10320 
   10321    Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and
   10322    distribution of this entire article is permitted in any medium,
   10323    provided this notice is preserved.
   10324 
   10325    These pages are [18]maintained by the GCC team. Last modified
   10326    2020-01-14[19].
   10327 
   10328 References
   10329 
   10330    1. http://www.gnu.org/
   10331    2. http://gcc.gnu.org/gcc-4.2/changes.html
   10332    3. http://gcc.gnu.org/gcc-4.2/changes.html
   10333    4. http://gcc.gnu.org/gcc-4.2/changes.html
   10334    5. http://gcc.gnu.org/gcc-4.2/changes.html
   10335    6. http://gcc.gnu.org/gcc-4.2/changes.html
   10336    7. http://gcc.gnu.org/gcc-4.2/buildstat.html
   10337    8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   10338    9. http://gcc.gnu.org/index.html
   10339   10. mailto:gcc (a] gcc.gnu.org
   10340   11. http://gcc.gnu.org/mirrors.html
   10341   12. http://gcc.gnu.org/git.html
   10342   13. https://gcc.gnu.org/onlinedocs/
   10343   14. mailto:gcc-help (a] gcc.gnu.org
   10344   15. mailto:gcc (a] gcc.gnu.org
   10345   16. https://gcc.gnu.org/lists.html
   10346   17. https://www.fsf.org/
   10347   18. https://gcc.gnu.org/about.html
   10348   19. http://validator.w3.org/check/referer
   10349 ======================================================================
   10350 http://gcc.gnu.org/gcc-4.2/changes.html
   10351                              GCC 4.2 Release Series
   10352                         Changes, New Features, and Fixes
   10353 
   10354 Caveats
   10355 
   10356      * GCC no longer accepts the -fshared-data option. This option has had
   10357        no effect in any GCC 4 release; the targets to which the option
   10358        used to apply had been removed before GCC 4.0.
   10359 
   10360 General Optimizer Improvements
   10361 
   10362      * New command-line options specify the possible relationships among
   10363        parameters and between parameters and global data. For example,
   10364        -fargument-noalias-anything specifies that arguments do not alias
   10365        any other storage.
   10366        Each language will automatically use whatever option is required by
   10367        the language standard. You should not need to use these options
   10368        yourself.
   10369 
   10370 New Languages and Language specific improvements
   10371 
   10372      * [1]OpenMP is now supported for the C, C++ and Fortran compilers.
   10373      * New command-line options -fstrict-overflow and -Wstrict-overflow
   10374        have been added. -fstrict-overflow tells the compiler that it may
   10375        assume that the program follows the strict signed overflow
   10376        semantics permitted for the language: for C and C++ this means that
   10377        the compiler may assume that signed overflow does not occur. For
   10378        example, a loop like
   10379       for (i = 1; i > 0; i *= 2)
   10380 
   10381        is presumably intended to continue looping until i overflows. With
   10382        -fstrict-overflow, the compiler may assume that signed overflow
   10383        will not occur, and transform this into an infinite loop.
   10384        -fstrict-overflow is turned on by default at -O2, and may be
   10385        disabled via -fno-strict-overflow. The -Wstrict-overflow option may
   10386        be used to warn about cases where the compiler assumes that signed
   10387        overflow will not occur. It takes five different levels:
   10388        -Wstrict-overflow=1 to 5. See the [2]documentation for details.
   10389        -Wstrict-overflow=1 is enabled by -Wall.
   10390      * The new command-line option -fno-toplevel-reorder directs GCC to
   10391        emit top-level functions, variables, and asm statements in the same
   10392        order that they appear in the input file. This is intended to
   10393        support existing code which relies on a particular ordering (for
   10394        example, code which uses top-level asm statements to switch
   10395        sections). For new code, it is generally better to use function and
   10396        variable attributes. The -fno-toplevel-reorder option may be used
   10397        for most cases which currently use -fno-unit-at-a-time. The
   10398        -fno-unit-at-a-time option will be removed in some future version
   10399        of GCC. If you know of a case which requires -fno-unit-at-a-time
   10400        which is not fixed by -fno-toplevel-reorder, please open a bug
   10401        report.
   10402 
   10403   C family
   10404 
   10405      * The pragma redefine_extname will now macro expand its tokens for
   10406        compatibility with SunPRO.
   10407      * In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct
   10408        GCC to handle inline functions as specified in the C99 standard. In
   10409        preparation for this, GCC 4.2 will warn about any use of non-static
   10410        inline functions in gnu99 or c99 mode. This new warning may be
   10411        disabled with the new gnu_inline function attribute or the new
   10412        -fgnu89-inline command-line option. Also, GCC 4.2 and later will
   10413        define one of the preprocessor macros __GNUC_GNU_INLINE__ or
   10414        __GNUC_STDC_INLINE__ to indicate the semantics of inline functions
   10415        in the current compilation.
   10416      * A new command-line option -Waddress has been added to warn about
   10417        suspicious uses of memory addresses as, for example, using the
   10418        address of a function in a conditional expression, and comparisons
   10419        against the memory address of a string literal. This warning is
   10420        enabled by -Wall.
   10421 
   10422   C++
   10423 
   10424      * C++ visibility handling has been overhauled.
   10425        Restricted visiblity is propagated from classes to members, from
   10426        functions to local statics, and from templates and template
   10427        arguments to instantiations, unless the latter has explicitly
   10428        declared visibility.
   10429        The visibility attribute for a class must come between the
   10430        class-key and the name, not after the closing brace.
   10431        Attributes are now allowed for enums and elaborated-type-specifiers
   10432        that only declare a type.
   10433        Members of the anonymous namespace are now local to a particular
   10434        translation unit, along with any other declarations which use them,
   10435        though they are still treated as having external linkage for
   10436        language semantics.
   10437      * The (undocumented) extension which permitted templates with default
   10438        arguments to be bound to template template parameters with fewer
   10439        parameters has been removed. For example:
   10440         template <template <typename> class C>
   10441         void f(C<double>) {}
   10442 
   10443         template <typename T, typename U = int>
   10444         struct S {};
   10445 
   10446         template void f(S<double>);
   10447 
   10448        is no longer accepted by G++. The reason this code is not accepted
   10449        is that S is a template with two parameters; therefore, it cannot
   10450        be bound to C which has only one parameter.
   10451      * The <?, >?, <?=, and >?= operators, deprecated in previous GCC
   10452        releases, have been removed.
   10453      * The command-line option -fconst-strings, deprecated in previous GCC
   10454        releases, has been removed.
   10455      * The configure variable enable-__cxa_atexit is now enabled by
   10456        default for more targets. Enabling this variable is necessary in
   10457        order for static destructors to be executed in the correct order,
   10458        but it depends upon the presence of a non-standard C library in the
   10459        target library in order to work. The variable is now enabled for
   10460        more targets which are known to have suitable C libraries.
   10461      * -Wextra will produce warnings for if statements with a semicolon as
   10462        the only body, to catch code like:
   10463          if (a);
   10464             return 1;
   10465          return 0;
   10466 
   10467        To suppress the warning in valid cases, use { } instead.
   10468      * The C++ front end now also produces strict aliasing warnings when
   10469        -fstrict-aliasing -Wstrict-aliasing is in effect.
   10470 
   10471     Runtime Library (libstdc++)
   10472 
   10473      * Added support for TR1 <random>, <complex>, and C compatibility
   10474        headers. In addition, a lock-free version of shared_ptr was
   10475        contributed as part of Phillip Jordan's Google Summer of Code
   10476        project on lock-free containers.
   10477      * In association with the Summer of Code work on lock-free
   10478        containers, the interface for atomic builtins was adjusted,
   10479        creating simpler alternatives for non-threaded code paths. Also,
   10480        usage was consolidated and all elements were moved from namespace
   10481        std to namespace__gnu_cxx. Affected interfaces are the functions
   10482        __exchange_and_add, __atomic_add, and the objects __mutex,
   10483        __recursive_mutex, and __scoped_lock.
   10484      * Support for versioning weak symbol names via namespace association
   10485        was added. However, as this changes the names of exported symbols,
   10486        this is turned off by default in the current ABI. Intrepid users
   10487        can enable this feature by using
   10488        --enable-symvers=gnu-versioned-namespace during configuration.
   10489      * Revised, simplified, and expanded policy-based associative
   10490        containers, including data types for tree and trie forms
   10491        (basic_tree, tree, trie), lists (list_update), and both
   10492        collision-chaining and probing hash-based containers
   10493        (basic_hash_table, cc_hash_table, gp_hash_table). More details per
   10494        the [3]documentation.
   10495      * The implementation of the debug mode was modified, whereby the
   10496        debug namespaces were nested inside of namespace std and namespace
   10497        __gnu_cxx in order to resolve some long standing corner cases
   10498        involving name lookup. Debug functionality from the policy-based
   10499        data structures was consolidated and enabled with the single macro,
   10500        _GLIBCXX_DEBUG. See PR 26142 for more information.
   10501      * Added extensions for type traits: __conditional_type,
   10502        __numeric_traits, __add_unsigned, __removed_unsigned, __enable_if.
   10503      * Added a typelist implementation for compile-time meta-programming.
   10504        Elements for typelist construction and operation can be found
   10505        within namespace __gnu_cxx::typelist.
   10506      * Added a new allocator, __gnu_cxx::throw_allocator, for testing
   10507        exception-safety.
   10508      * Enabled library-wide visibility control, allowing -fvisibility to
   10509        be used.
   10510      * Consolidated all nested namespaces and the conversion of
   10511        __gnu_internal implementation-private details to anonymous
   10512        namespaces whenever possible.
   10513      * Implemented LWG resolutions DR 431 and DR 538.
   10514 
   10515   Fortran
   10516 
   10517      * Support for allocatable components has been added (TR 15581 and
   10518        Fortran 2003).
   10519      * Support for the Fortran 2003 streaming IO extension has been added.
   10520      * The GNU Fortran compiler now uses 4-byte record markers by default
   10521        for unformatted files to be compatible with g77 and most other
   10522        compilers. The implementation allows for records greater than 2 GB
   10523        and is compatible with several other compilers. Older versions of
   10524        gfortran used 8-byte record markers by default (on most systems).
   10525        In order to change the length of the record markers, e.g. to read
   10526        unformatted files created by older gfortran versions, the
   10527        [4]-frecord-marker=8 option can be used.
   10528 
   10529   Java (GCJ)
   10530 
   10531      * A new command-line option -static-libgcj has been added for targets
   10532        that use a linker compatible with GNU Binutils. As its name
   10533        implies, this causes libgcj to be linked statically. In some cases
   10534        this causes the resulting executable to start faster and use less
   10535        memory than if the shared version of libgcj were used. However
   10536        caution should be used as it can also cause essential parts of the
   10537        library to be omitted. Some of these issues are discussed in:
   10538        [5]https://gcc.gnu.org/wiki/Statically_linking_libgcj
   10539      * fastjar is no longer bundled with GCC. To build libgcj, you will
   10540        need either InfoZIP (both zip and unzip) or an external jar
   10541        program. In the former case, the GCC build will install a jar shell
   10542        script that is based on InfoZIP and provides the same functionality
   10543        as fastjar.
   10544 
   10545 New Targets and Target Specific Improvements
   10546 
   10547   IA-32/x86-64
   10548 
   10549      * -mtune=generic can now be used to generate code running well on
   10550        common x86 chips. This includes AMD Athlon, AMD Opteron, Intel
   10551        Pentium-M, Intel Pentium 4 and Intel Core 2.
   10552      * -mtune=native and -march=native will produce code optimized for the
   10553        host architecture as detected using the cpuid instruction.
   10554      * Added a new command-line option -fstackrealign and and
   10555        __attribute__ ((force_align_arg_pointer)) to realign the stack at
   10556        runtime. This allows functions compiled with a vector-aligned stack
   10557        to be invoked from legacy objects that keep only word-alignment.
   10558 
   10559   SPARC
   10560 
   10561      * The default CPU setting has been changed from V7 to V9 in 32-bit
   10562        mode on Solaris 7 and above. This is already the case in 64-bit
   10563        mode. It can be overridden by specifying --with-cpu at configure
   10564        time.
   10565      * Back-end support of built-in functions for atomic memory access has
   10566        been implemented.
   10567      * Support for the Sun UltraSPARC T1 (Niagara) processor has been
   10568        added.
   10569 
   10570   M32C
   10571 
   10572      * Various bug fixes have made some functions (notably, functions
   10573        returning structures) incompatible with previous releases.
   10574        Recompiling all libraries is recommended. Note that code quality
   10575        has considerably improved since 4.1, making a recompile even more
   10576        beneficial.
   10577 
   10578   MIPS
   10579 
   10580      * Added support for the Broadcom SB-1A core.
   10581 
   10582   IA-64
   10583 
   10584      * Added support for IA-64 data and control speculation. By default
   10585        speculation is enabled only during second scheduler pass. A number
   10586        of machine flags was introduced to control the usage of speculation
   10587        for both scheduler passes.
   10588 
   10589   HPPA
   10590 
   10591      * Added Java language support (libffi and libjava) for 32-bit HP-UX
   10592        11 target.
   10593 
   10594 Obsolete Systems
   10595 
   10596 Documentation improvements
   10597 
   10598   PDF Documentation
   10599 
   10600      * A make pdf target has been added to the top-level makefile,
   10601        enabling automated production of PDF documentation files.
   10602        (Front-ends external to GCC should modify their Make-lang.in file
   10603        to add a lang.pdf: target.)
   10604 
   10605 Other significant improvements
   10606 
   10607   Build system improvements
   10608 
   10609      * All the components of the compiler are now bootstrapped by default.
   10610        This improves the resilience to bugs in the system compiler or
   10611        binary compatibility problems, as well as providing better testing
   10612        of GCC 4.2 itself. In addition, if you build the compiler from a
   10613        combined tree, the assembler, linker, etc. will also be
   10614        bootstrapped (i.e. built with themselves).
   10615        You can disable this behavior, and go back to the pre-GCC 4.2 set
   10616        up, by configuring GCC with --disable-bootstrap.
   10617      * The rules that configure follows to find target tools resemble more
   10618        closely the locations that the built compiler will search. In
   10619        addition, you can use the new configure option --with-target-tools
   10620        to specify where to find the target tools used during the build,
   10621        without affecting what the built compiler will use.
   10622        This can be especially useful when building packages of GCC. For
   10623        example, you may want to build GCC with GNU as or ld, even if the
   10624        resulting compiler to work with the native assembler and linker. To
   10625        do so, you can use --with-target-tools to point to the native
   10626        tools.
   10627 
   10628   Incompatible changes to the build system
   10629 
   10630      * Front-ends external to GCC should modify their Make-lang.in file to
   10631        replace double-colon rules (e.g. dvi::) with normal rules (like
   10632        lang.dvi:). Front-end makefile hooks do not use double-colon rules
   10633        anymore.
   10634      * Up to GCC 4.1, a popular way to specify the target tools used
   10635        during the build was to create directories named gas, binutils,
   10636        etc. in the build tree, and create links to the tools from there.
   10637        This does not work any more when the compiler is bootstrapped. The
   10638        new configure option --with-target-tools provides a better way to
   10639        achieve the same effect, and works for all native and cross
   10640        settings.
   10641 
   10642 
   10643     For questions related to the use of GCC, please consult these web
   10644     pages and the [6]GCC manuals. If that fails, the
   10645     [7]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   10646     web pages and the development of GCC are welcome on our developer
   10647     list at [8]gcc (a] gcc.gnu.org. All of [9]our lists have public archives.
   10648 
   10649    Copyright (C) [10]Free Software Foundation, Inc. Verbatim copying and
   10650    distribution of this entire article is permitted in any medium,
   10651    provided this notice is preserved.
   10652 
   10653    These pages are [11]maintained by the GCC team. Last modified
   10654    2019-11-28[12].
   10655 
   10656 References
   10657 
   10658    1. http://gcc.gnu.org/projects/gomp/
   10659    2. https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
   10660    3. https://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html
   10661    4. https://gcc.gnu.org/onlinedocs/gfortran/Runtime-Options.html
   10662    5. https://gcc.gnu.org/wiki/Statically_linking_libgcj
   10663    6. https://gcc.gnu.org/onlinedocs/
   10664    7. mailto:gcc-help (a] gcc.gnu.org
   10665    8. mailto:gcc (a] gcc.gnu.org
   10666    9. https://gcc.gnu.org/lists.html
   10667   10. https://www.fsf.org/
   10668   11. https://gcc.gnu.org/about.html
   10669   12. http://validator.w3.org/check/referer
   10670 ======================================================================
   10671 http://gcc.gnu.org/gcc-4.1/index.html
   10672                              GCC 4.1 Release Series
   10673 
   10674    (This release series is no longer supported.)
   10675 
   10676    February 13, 2007
   10677 
   10678    The [1]GNU project and the GCC developers are pleased to announce the
   10679    release of GCC 4.1.2.
   10680 
   10681    This release is a bug-fix release, containing fixes for regressions in
   10682    GCC 4.1.1 relative to previous releases of GCC.
   10683 
   10684 Release History
   10685 
   10686    GCC 4.1.2
   10687           February 13, 2007 ([2]changes)
   10688 
   10689    GCC 4.1.1
   10690           May 24, 2006 ([3]changes)
   10691 
   10692    GCC 4.1.0
   10693           February 28, 2006 ([4]changes)
   10694 
   10695 References and Acknowledgements
   10696 
   10697    GCC used to stand for the GNU C Compiler, but since the compiler
   10698    supports several other languages aside from C, it now stands for the
   10699    GNU Compiler Collection.
   10700 
   10701    A list of [5]successful builds is updated as new information becomes
   10702    available.
   10703 
   10704    The GCC developers would like to thank the numerous people that have
   10705    contributed new features, improvements, bug fixes, and other changes as
   10706    well as test results to GCC. This [6]amazing group of volunteers is
   10707    what makes GCC successful.
   10708 
   10709    For additional information about GCC please refer to the [7]GCC project
   10710    web site or contact the [8]GCC development mailing list.
   10711 
   10712    To obtain GCC please use [9]our mirror sites or [10]our version control
   10713    system.
   10714 
   10715 
   10716     For questions related to the use of GCC, please consult these web
   10717     pages and the [11]GCC manuals. If that fails, the
   10718     [12]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   10719     web pages and the development of GCC are welcome on our developer
   10720     list at [13]gcc (a] gcc.gnu.org. All of [14]our lists have public
   10721     archives.
   10722 
   10723    Copyright (C) [15]Free Software Foundation, Inc. Verbatim copying and
   10724    distribution of this entire article is permitted in any medium,
   10725    provided this notice is preserved.
   10726 
   10727    These pages are [16]maintained by the GCC team. Last modified
   10728    2020-01-14[17].
   10729 
   10730 References
   10731 
   10732    1. http://www.gnu.org/
   10733    2. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2
   10734    3. http://gcc.gnu.org/gcc-4.1/changes.html
   10735    4. http://gcc.gnu.org/gcc-4.1/changes.html
   10736    5. http://gcc.gnu.org/gcc-4.1/buildstat.html
   10737    6. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   10738    7. http://gcc.gnu.org/index.html
   10739    8. mailto:gcc (a] gcc.gnu.org
   10740    9. http://gcc.gnu.org/mirrors.html
   10741   10. http://gcc.gnu.org/git.html
   10742   11. https://gcc.gnu.org/onlinedocs/
   10743   12. mailto:gcc-help (a] gcc.gnu.org
   10744   13. mailto:gcc (a] gcc.gnu.org
   10745   14. https://gcc.gnu.org/lists.html
   10746   15. https://www.fsf.org/
   10747   16. https://gcc.gnu.org/about.html
   10748   17. http://validator.w3.org/check/referer
   10749 ======================================================================
   10750 http://gcc.gnu.org/gcc-4.1/changes.html
   10751                              GCC 4.1 Release Series
   10752                         Changes, New Features, and Fixes
   10753 
   10754    The latest release in the 4.1 release series is [1]GCC 4.1.2.
   10755 
   10756 Caveats
   10757 
   10758 General Optimizer Improvements
   10759 
   10760      * GCC now has infrastructure for inter-procedural optimizations and
   10761        the following inter-procedural optimizations are implemented:
   10762           + Profile guided inlining. When doing profile feedback guided
   10763             optimization, GCC can now use the profile to make better
   10764             informed decisions on whether inlining of a function is
   10765             profitable or not. This means that GCC will no longer inline
   10766             functions at call sites that are not executed very often, and
   10767             that functions at hot call sites are more likely to be
   10768             inlined.
   10769             A new parameter min-inline-recursive-probability is also now
   10770             available to throttle recursive inlining of functions with
   10771             small average recursive depths.
   10772           + Discovery of pure and const functions, a form of side-effects
   10773             analysis. While older GCC releases could also discover such
   10774             special functions, the new IPA-based pass runs earlier so that
   10775             the results are available to more optimizers. The pass is also
   10776             simply more powerful than the old one.
   10777           + Analysis of references to static variables and type escape
   10778             analysis, also forms of side-effects analysis. The results of
   10779             these passes allow the compiler to be less conservative about
   10780             call-clobbered variables and references. This results in more
   10781             redundant loads being eliminated and in making static
   10782             variables candidates for register promotion.
   10783           + Improvement of RTL-based alias analysis. The results of type
   10784             escape analysis are fed to the RTL type-based alias analyzer,
   10785             allowing it to disambiguate more memory references.
   10786           + Interprocedural constant propagation and function versioning.
   10787             This pass looks for functions that are always called with the
   10788             same constant value for one or more of the function arguments,
   10789             and propagates those constants into those functions.
   10790           + GCC will now eliminate static variables whose usage was
   10791             optimized out.
   10792           + -fwhole-program --combine can now be used to make all
   10793             functions in program static allowing whole program
   10794             optimization. As an exception, the main function and all
   10795             functions marked with the new externally_visible attribute are
   10796             kept global so that programs can link with runtime libraries.
   10797      * GCC can now do a form of partial dead code elimination (PDCE) that
   10798        allows code motion of expressions to the paths where the result of
   10799        the expression is actually needed. This is not always a win, so the
   10800        pass has been limited to only consider profitable cases. Here is an
   10801        example:
   10802     int foo (int *, int *);
   10803     int
   10804     bar (int d)
   10805     {
   10806       int a, b, c;
   10807       b = d + 1;
   10808       c = d + 2;
   10809       a = b + c;
   10810       if (d)
   10811         {
   10812           foo (&b, &c);
   10813           a = b + c;
   10814         }
   10815       printf ("%d\n", a);
   10816     }
   10817 
   10818        The a = b + c can be sunk to right before the printf. Normal code
   10819        sinking will not do this, it will sink the first one above into the
   10820        else-branch of the conditional jump, which still gives you two
   10821        copies of the code.
   10822      * GCC now has a value range propagation pass. This allows the
   10823        compiler to eliminate bounds checks and branches. The results of
   10824        the pass can also be used to accurately compute branch
   10825        probabilities.
   10826      * The pass to convert PHI nodes to straight-line code (a form of
   10827        if-conversion for GIMPLE) has been improved significantly. The two
   10828        most significant improvements are an improved algorithm to
   10829        determine the order in which the PHI nodes are considered, and an
   10830        improvement that allow the pass to consider if-conversions of basic
   10831        blocks with more than two predecessors.
   10832      * Alias analysis improvements. GCC can now differentiate between
   10833        different fields of structures in Tree-SSA's virtual operands form.
   10834        This lets stores/loads from non-overlapping structure fields not
   10835        conflict. A new algorithm to compute points-to sets was contributed
   10836        that can allows GCC to see now that p->a and p->b, where p is a
   10837        pointer to a structure, can never point to the same field.
   10838      * Various enhancements to auto-vectorization:
   10839           + Incrementally preserve SSA form when vectorizing.
   10840           + Incrementally preserve loop-closed form when vectorizing.
   10841           + Improvements to peeling for alignment: generate better code
   10842             when the misalignment of an access is known at compile time,
   10843             or when different accesses are known to have the same
   10844             misalignment, even if the misalignment amount itself is
   10845             unknown.
   10846           + Consider dependence distance in the vectorizer.
   10847           + Externalize generic parts of data reference analysis to make
   10848             this analysis available to other passes.
   10849           + Vectorization of conditional code.
   10850           + Reduction support.
   10851      * GCC can now partition functions in sections of hot and cold code.
   10852        This can significantly improve performance due to better
   10853        instruction cache locality. This feature works best together with
   10854        profile feedback driven optimization.
   10855      * A new pass to avoid saving of unneeded arguments to the stack in
   10856        vararg functions if the compiler can prove that they will not be
   10857        needed.
   10858      * Transition of basic block profiling to tree level implementation
   10859        has been completed. The new implementation should be considerably
   10860        more reliable (hopefully avoiding profile mismatch errors when
   10861        using -fprofile-use or -fbranch-probabilities) and can be used to
   10862        drive higher level optimizations, such as inlining.
   10863        The -ftree-based-profiling command-line option was removed and
   10864        -fprofile-use now implies disabling old RTL level loop optimizer
   10865        (-fno-loop-optimize). Speculative prefetching optimization
   10866        (originally enabled by -fspeculative-prefetching) was removed.
   10867 
   10868 New Languages and Language specific improvements
   10869 
   10870   C and Objective-C
   10871 
   10872      * The old Bison-based C and Objective-C parser has been replaced by a
   10873        new, faster hand-written recursive-descent parser.
   10874 
   10875   Ada
   10876 
   10877      * The build infrastructure for the Ada runtime library and tools has
   10878        been changed to be better integrated with the rest of the build
   10879        infrastructure of GCC. This should make doing cross builds of Ada a
   10880        bit easier.
   10881 
   10882   C++
   10883 
   10884      * ARM-style name-injection of friend declarations is no longer the
   10885        default. For example:
   10886           struct S {
   10887             friend void f();
   10888           };
   10889 
   10890           void g() { f(); }
   10891        will not be accepted; instead a declaration of f will need to be
   10892        present outside of the scope of S. The new -ffriend-injection
   10893        option will enable the old behavior.
   10894      * The (undocumented) extension which permitted templates with default
   10895        arguments to be bound to template template parameters with fewer
   10896        parameters has been deprecated, and will be removed in the next
   10897        major release of G++. For example:
   10898        template <template <typename> class C>
   10899        void f(C<double>) {}
   10900 
   10901        template <typename T, typename U = int>
   10902        struct S {};
   10903 
   10904        template void f(S<double>);
   10905 
   10906        makes use of the deprecated extension. The reason this code is not
   10907        valid ISO C++ is that S is a template with two parameters;
   10908        therefore, it cannot be bound to C which has only one parameter.
   10909 
   10910     Runtime Library (libstdc++)
   10911 
   10912      * Optimization work:
   10913           + A new implementation of std::search_n is provided, better
   10914             performing in case of random access iterators.
   10915           + Added further efficient specializations of istream functions,
   10916             i.e., character array and string extractors.
   10917           + Other smaller improvements throughout.
   10918      * Policy-based associative containers, designed for high-performance,
   10919        flexibility and semantic safety are delivered in ext/pb_assoc.
   10920      * A versatile string class, __gnu_cxx::__versa_string, providing
   10921        facilities conforming to the standard requirements for
   10922        basic_string, is delivered in <ext/vstring.h>. In particular:
   10923           + Two base classes are provided: the default one avoids
   10924             reference counting and is optimized for short strings; the
   10925             alternate one, still uses it while improving in a few low
   10926             level areas (e.g., alignment). See vstring_fwd.h for some
   10927             useful typedefs.
   10928           + Various algorithms have been rewritten (e.g., replace), the
   10929             code streamlined and simple optimizations added.
   10930           + Option 3 of DR 431 is implemented for both available bases,
   10931             thus improving the support for stateful allocators.
   10932      * As usual, many bugs have been fixed (e.g., libstdc++/13583,
   10933        libstdc++/23953) and LWG resolutions put into effect for the first
   10934        time (e.g., DR 280, DR 464, N1780 recommendations for DR 233, TR1
   10935        Issue 6.19). The implementation status of TR1 is now tracked in the
   10936        docs in tr1.html.
   10937 
   10938   Objective-C++
   10939 
   10940      * A new language front end for Objective-C++ has been added. This
   10941        language allows users to mix the object oriented features of
   10942        Objective-C with those of C++.
   10943 
   10944   Java (GCJ)
   10945 
   10946      * Core library (libgcj) updates based on GNU Classpath 0.15 - 0.19
   10947        features (plus some 0.20 bug-fixes)
   10948           + Networking
   10949                o The java.net.HttpURLConnection implementation no longer
   10950                  buffers the entire response body in memory. This means
   10951                  that response bodies larger than available memory can now
   10952                  be handled.
   10953           + (N)IO
   10954                o NIO FileChannel.map implementation, fast bulk put
   10955                  implementation for DirectByteBuffer (speeds up this
   10956                  method 10x).
   10957                o FileChannel.lock() and FileChannel.force() implemented.
   10958           + XML
   10959                o gnu.xml fix for nodes created outside a namespace
   10960                  context.
   10961                o Add support for output indenting and
   10962                  cdata-section-elements output instruction in
   10963                  xml.transform.
   10964                o xml.xpath corrections for cases where elements/attributes
   10965                  might have been created in non-namespace-aware mode.
   10966                  Corrections to handling of XSL variables and minor
   10967                  conformance updates.
   10968           + AWT
   10969                o GNU JAWT implementation, the AWT Native Interface, which
   10970                  allows direct access to native screen resources from
   10971                  within a Canvas's paint method. GNU Classpath Examples
   10972                  comes with a Demo, see libjava/classpath/examples/README.
   10973                o awt.datatransfer updated to 1.5 with support for
   10974                  FlavorEvents. The gtk+ awt peers now allow copy/paste of
   10975                  text, images, URIs/files and serialized objects with
   10976                  other applications and tracking clipboard change events
   10977                  with gtk+ 2.6 (for gtk+ 2.4 only text and serialized
   10978                  objects are supported). A GNU Classpath Examples
   10979                  datatransfer Demo was added to show the new
   10980                  functionality.
   10981                o Split gtk+ awt peers event handling in two threads and
   10982                  improve gdk lock handling (solves several awt lock ups).
   10983                o Speed up awt Image loading.
   10984                o Better gtk+ scrollbar peer implementation when using gtk+
   10985                  >= 2.6.
   10986                o Handle image loading errors correctly for gdkpixbuf and
   10987                  MediaTracker.
   10988                o Better handle GDK lock. Properly prefix gtkpeer native
   10989                  functions (cp_gtk).
   10990                o GdkGraphics2D has been updated to use Cairo 0.5.x or
   10991                  higher.
   10992                o BufferedImage and GtkImage rewrites. All image drawing
   10993                  operations should now work correctly (flipping requires
   10994                  gtk+ >= 2.6)
   10995                o Future Graphics2D, image and text work is documented at:
   10996                  [2]http://developer.classpath.org/mediation/ClasspathGrap
   10997                  hicsImagesText
   10998                o When gtk+ 2.6 or higher is installed the default log
   10999                  handler will produce stack traces whenever a WARNING,
   11000                  CRITICAL or ERROR message is produced.
   11001           + Free Swing
   11002                o The RepaintManager has been reworked for more efficient
   11003                  painting, especially for large GUIs.
   11004                o The layout manager OverlayLayout has been implemented,
   11005                  the BoxLayout has been rewritten to make use of the
   11006                  SizeRequirements utility class and caching for more
   11007                  efficient layout.
   11008                o Improved accessibility support.
   11009                o Significant progress has been made in the implementation
   11010                  of the javax.swing.plaf.metal package, with most UI
   11011                  delegates in a working state now. Please test this with
   11012                  your own applications and provide feedback that will help
   11013                  us to improve this package.
   11014                o The GUI demo (gnu.classpath.examples.swing.Demo) has been
   11015                  extended to highlight various features in our Free Swing
   11016                  implementation. And it includes a look and feel switcher
   11017                  for Metal (default), Ocean and GNU themes.
   11018                o The javax.swing.plaf.multi package is now implemented.
   11019                o Editing and several key actions for JTree and JTable were
   11020                  implemented.
   11021                o Lots of icons and look and feel improvements for Free
   11022                  Swing basic and metal themes were added. Try running the
   11023                  GNU Classpath Swing Demo in examples
   11024                  (gnu.classpath.examples.swing.Demo) with:
   11025                  -Dswing.defaultlaf=javax.swing.plaf.basic.BasicLookAndFee
   11026                  l or
   11027                  -Dswing.defaultlaf=javax.swing.plaf.metal.MetalLookAndFee
   11028                  l
   11029                o Start of styled text capabilites for java.swing.text.
   11030                o DefaultMutableTreeNode pre-order, post-order, depth-first
   11031                  and breadth-first traversal enumerations implemented.
   11032                o JInternalFrame colors and titlebar draw properly.
   11033                o JTree is working up to par (icons, selection and keyboard
   11034                  traversal).
   11035                o JMenus were made more compatible in visual and
   11036                  programmatic behavior.
   11037                o JTable changeSelection and multiple selections
   11038                  implemented.
   11039                o JButton and JToggleButton change states work properly
   11040                  now.
   11041                o JFileChooser fixes.
   11042                o revalidate() and repaint() fixes which make Free Swing
   11043                  much more responsive.
   11044                o MetalIconFactory implemented.
   11045                o Free Swing Top-Level Compatibility. JFrame, JDialog,
   11046                  JApplet, JInternalFrame, and JWindow are now 1.5
   11047                  compatible in the sense that you can call add() and
   11048                  setLayout() directly on them, which will have the same
   11049                  effect as calling getContentPane().add() and
   11050                  getContentPane().setLayout().
   11051                o The JTree interface has been completed. JTrees now
   11052                  recognizes mouse clicks and selections work.
   11053                o BoxLayout works properly now.
   11054                o Fixed GrayFilter to actually work.
   11055                o Metal SplitPane implemented.
   11056                o Lots of Free Swing text and editor stuff work now.
   11057           + Free RMI and Corba
   11058                o Andrew Watson, Vice President and Technical Director of
   11059                  the Object Management Group, has officially assigned us
   11060                  20 bit Vendor Minor Code Id: 0x47430 ("GC") that will
   11061                  mark remote classpath-specific system exceptions.
   11062                  Obtaining the VMCID means that GNU Classpath now is a
   11063                  recogniseable type of node in a highly interoperable
   11064                  CORBA world.
   11065                o GNU Classpath now includes the first working draft to
   11066                  support the RMI over IIOP protocol. The current
   11067                  implementation is capable of remote invocations,
   11068                  transferring various Serializables and Externalizables
   11069                  via RMI-IIOP protocol. It can flatten graphs and, at
   11070                  least for the simple cases, is interoperable with 1.5
   11071                  JDKs.
   11072                o org.omg.PortableInterceptor and related functionality in
   11073                  other packages is now implemented:
   11074                     # The sever and client interceptors work as required
   11075                       since 1.4.
   11076                     # The IOR interceptor works as needed for 1.5.
   11077                o The org.omg.DynamicAny package is completed and passes
   11078                  the prepared tests.
   11079                o The Portable Object Adapter should now support the output
   11080                  of the recent IDL to java compilers. These compilers now
   11081                  generate servants and not CORBA objects as before, making
   11082                  the output depend on the existing POA implementation.
   11083                  Completing POA means that such code can already be tried
   11084                  to run on Classpath. Our POA is tested for the following
   11085                  usager scenarios:
   11086                     # POA converts servant to the CORBA object.
   11087                     # Servant provides to the CORBA object.
   11088                     # POA activates new CORBA object with the given Object
   11089                       Id (byte array) that is later accessible for the
   11090                       servant.
   11091                     # During the first call, the ServantActivator provides
   11092                       servant for this and all subsequent calls on the
   11093                       current object.
   11094                     # During each call, the ServantLocator provides
   11095                       servant for this call only.
   11096                     # ServantLocator or ServantActivator forwards call to
   11097                       another server.
   11098                     # POA has a single servant, responsible for all
   11099                       objects.
   11100                     # POA has a default servant, but some objects are
   11101                       explicitly connected to they specific servants.
   11102                  The POA is verified using tests from the former
   11103                  cost.omg.org.
   11104                o The CORBA implementation is now a working prototype that
   11105                  should support features up to 1.3 inclusive. We invite
   11106                  groups writing CORBA dependent applications to try
   11107                  Classpath implementation, reporting any possible bugs.
   11108                  The CORBA prototype is interoperable with Sun's
   11109                  implementation v 1.4, transferring object references,
   11110                  primitive types, narrow and wide strings, arrays,
   11111                  structures, trees, abstract interfaces and value types
   11112                  (feature of CORBA 2.3) between these two platforms.
   11113                  Remote exceptions are transferred and handled correctly.
   11114                  The stringified object references (IORs) from various
   11115                  sources are parsed as required. The transient (for
   11116                  current session) and permanent (till jre restart)
   11117                  redirections work. Both Little and Big Endian encoded
   11118                  messages are accepted. The implementation is verified
   11119                  using tests from the former cost.omg.org. The current
   11120                  release includes working examples (see the examples
   11121                  directory), demonstrating the client-server
   11122                  communication, using either CORBA Request or IDL-based
   11123                  stub (usually generated by a IDL to java compiler). These
   11124                  examples also show how to use the Classpath CORBA naming
   11125                  service. The IDL to java compiler is not yet written, but
   11126                  as our library must be compatible, it naturally accepts
   11127                  the output of other idlj implementations.
   11128           + Misc
   11129                o Updated TimeZone data against Olson tzdata2005l.
   11130                o Make zip and jar packages UTF-8 clean.
   11131                o "native" code builds and compiles (warning free) on
   11132                  Darwin and Solaris.
   11133                o java.util.logging.FileHandler now rotates files.
   11134                o Start of a generic JDWP framework in gnu/classpath/jdwp.
   11135                  This is unfinished, but feedback (at classpath (a] gnu.org)
   11136                  from runtime hackers is greatly appreciated. Although
   11137                  most of the work is currently being done around gcj/gij
   11138                  we want this framework to be as VM neutral as possible.
   11139                  Early design is described in:
   11140                  [3]https://gcc.gnu.org/ml/java/2005-05/msg00260.html
   11141                o QT4 AWT peers, enable by giving configure
   11142                  --enable-qt-peer. Included, but not ready for production
   11143                  yet. They are explicitly disabled and not supported. But
   11144                  if you want to help with the development of these new
   11145                  features we are interested in feedback. You will have to
   11146                  explicitly enable them to try them out (and they will
   11147                  most likely contain bugs).
   11148                o Documentation fixes all over the place. See
   11149                  [4]http://developer.classpath.org/doc/
   11150 
   11151 New Targets and Target Specific Improvements
   11152 
   11153   IA-32/x86-64
   11154 
   11155      * The x86-64 medium model (that allows building applications whose
   11156        data segment exceeds 4GB) was redesigned to match latest ABI draft.
   11157        New implementation split large datastructures into separate segment
   11158        improving performance of accesses to small datastructures and also
   11159        allows linking of small model libraries into medium model programs
   11160        as long as the libraries are not accessing the large datastructures
   11161        directly. Medium model is also supported in position independent
   11162        code now.
   11163        The ABI change results in partial incompatibility among medium
   11164        model objects. Linking medium model libraries (or objects) compiled
   11165        with new compiler into medium model program compiled with older
   11166        will likely result in exceeding ranges of relocations.
   11167        Binutils 2.16.91 or newer are required for compiling medium model
   11168        now.
   11169 
   11170   RS6000 (POWER/PowerPC)
   11171 
   11172      * The AltiVec vector primitives in <altivec.h> are now implemented in
   11173        a way that puts a smaller burden on the preprocessor, instead
   11174        processing the "overloading" in the front ends. This should benefit
   11175        compilation speed on AltiVec vector code.
   11176      * AltiVec initializers now are generated more efficiently.
   11177      * The popcountb instruction available on POWER5 now is generated.
   11178      * The floating point round to integer instructions available on
   11179        POWER5+ now is generated.
   11180      * Floating point divides can be synthesized using the floating point
   11181        reciprocal estimate instructions.
   11182      * Double precision floating point constants are initialized as single
   11183        precision values if they can be represented exactly.
   11184 
   11185   S/390, zSeries and System z9
   11186 
   11187      * Support for the IBM System z9 109 processor has been added. When
   11188        using the -march=z9-109 option, the compiler will generate code
   11189        making use of instructions provided by the extended immediate
   11190        facility.
   11191      * Support for 128-bit IEEE floating point has been added. When using
   11192        the -mlong-double-128 option, the compiler will map the long double
   11193        data type to 128-bit IEEE floating point. Using this option
   11194        constitutes an ABI change, and requires glibc support.
   11195      * Various changes to improve performance of generated code have been
   11196        implemented, including:
   11197           + In functions that do not require a literal pool, register %r13
   11198             (which is traditionally reserved as literal pool pointer), can
   11199             now be freely used for other purposes by the compiler.
   11200           + More precise tracking of register use allows the compiler to
   11201             generate more efficient function prolog and epilog code in
   11202             certain cases.
   11203           + The SEARCH STRING, COMPARE LOGICAL STRING, and MOVE STRING
   11204             instructions are now used to implement C string functions.
   11205           + The MOVE CHARACTER instruction with single byte overlap is now
   11206             used to implement the memset function with non-zero fill byte.
   11207           + The LOAD ZERO instructions are now used where appropriate.
   11208           + The INSERT CHARACTERS UNDER MASK, STORE CHARACTERS UNDER MASK,
   11209             and INSERT IMMEDIATE instructions are now used more frequently
   11210             to optimize bitfield operations.
   11211           + The BRANCH ON COUNT instruction is now used more frequently.
   11212             In particular, the fact that a loop contains a subroutine call
   11213             no longer prevents the compiler from using this instruction.
   11214           + The compiler is now aware that all shift and rotate
   11215             instructions implicitly truncate the shift count to six bits.
   11216      * Back-end support for the following generic features has been
   11217        implemented:
   11218           + The full set of [5]built-in functions for atomic memory
   11219             access.
   11220           + The -fstack-protector feature.
   11221           + The optimization pass avoiding unnecessary stores of incoming
   11222             argument registers in functions with variable argument list.
   11223 
   11224   SPARC
   11225 
   11226      * The default code model in 64-bit mode has been changed from
   11227        Medium/Anywhere to Medium/Middle on Solaris.
   11228      * TLS support is disabled by default on Solaris prior to release 10.
   11229        It can be enabled on TLS-capable Solaris 9 versions (4/04 release
   11230        and later) by specifying --enable-tls at configure time.
   11231 
   11232   MorphoSys
   11233 
   11234      * Support has been added for this new architecture.
   11235 
   11236 Obsolete Systems
   11237 
   11238 Documentation improvements
   11239 
   11240 Other significant improvements
   11241 
   11242      * GCC can now emit code for protecting applications from
   11243        stack-smashing attacks. The protection is realized by buffer
   11244        overflow detection and reordering of stack variables to avoid
   11245        pointer corruption.
   11246      * Some built-in functions have been fortified to protect them against
   11247        various buffer overflow (and format string) vulnerabilities.
   11248        Compared to the mudflap bounds checking feature, the safe builtins
   11249        have far smaller overhead. This means that programs built using
   11250        safe builtins should not experience any measurable slowdown.
   11251 
   11252 GCC 4.1.2
   11253 
   11254    This is the [6]list of problem reports (PRs) from GCC's bug tracking
   11255    system that are known to be fixed in the 4.1.2 release. This list might
   11256    not be complete (that is, it is possible that some PRs that have been
   11257    fixed are not listed here).
   11258 
   11259    When generating code for a shared library, GCC now recognizes that
   11260    global functions may be replaced when the program runs. Therefore, it
   11261    is now more conservative in deducing information from the bodies of
   11262    functions. For example, in this example:
   11263     void f() {}
   11264     void g() {
   11265      try { f(); }
   11266      catch (...) {
   11267        cout << "Exception";
   11268      }
   11269     }
   11270 
   11271    G++ would previously have optimized away the catch clause, since it
   11272    would have concluded that f cannot throw exceptions. Because users may
   11273    replace f with another function in the main body of the program, this
   11274    optimization is unsafe, and is no longer performed. If you wish G++ to
   11275    continue to optimize as before, you must add a throw() clause to the
   11276    declaration of f to make clear that it does not throw exceptions.
   11277 
   11278 
   11279     For questions related to the use of GCC, please consult these web
   11280     pages and the [7]GCC manuals. If that fails, the
   11281     [8]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   11282     web pages and the development of GCC are welcome on our developer
   11283     list at [9]gcc (a] gcc.gnu.org. All of [10]our lists have public
   11284     archives.
   11285 
   11286    Copyright (C) [11]Free Software Foundation, Inc. Verbatim copying and
   11287    distribution of this entire article is permitted in any medium,
   11288    provided this notice is preserved.
   11289 
   11290    These pages are [12]maintained by the GCC team. Last modified
   11291    2019-11-28[13].
   11292 
   11293 References
   11294 
   11295    1. http://gcc.gnu.org/gcc-4.1/changes.html#4.1.2
   11296    2. http://developer.classpath.org/mediation/ClasspathGraphicsImagesText
   11297    3. https://gcc.gnu.org/ml/java/2005-05/msg00260.html
   11298    4. http://developer.classpath.org/doc/
   11299    5. https://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
   11300    6. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.1.2
   11301    7. https://gcc.gnu.org/onlinedocs/
   11302    8. mailto:gcc-help (a] gcc.gnu.org
   11303    9. mailto:gcc (a] gcc.gnu.org
   11304   10. https://gcc.gnu.org/lists.html
   11305   11. https://www.fsf.org/
   11306   12. https://gcc.gnu.org/about.html
   11307   13. http://validator.w3.org/check/referer
   11308 ======================================================================
   11309 http://gcc.gnu.org/gcc-4.0/index.html
   11310                              GCC 4.0 Release Series
   11311 
   11312    (This release series is no longer supported.)
   11313 
   11314    January 31, 2007
   11315 
   11316    The [1]GNU project and the GCC developers are pleased to announce the
   11317    release of GCC 4.0.4.
   11318 
   11319    This release is a bug-fix release, containing fixes for regressions in
   11320    GCC 4.0.3 relative to previous releases of GCC.
   11321 
   11322 Release History
   11323 
   11324    GCC 4.0.4
   11325           January 31, 2007 ([2]changes)
   11326 
   11327    GCC 4.0.3
   11328           March 10, 2006 ([3]changes)
   11329 
   11330    GCC 4.0.2
   11331           September 28, 2005 ([4]changes)
   11332 
   11333    GCC 4.0.1
   11334           July 7, 2005 ([5]changes)
   11335 
   11336    GCC 4.0.0
   11337           April 20, 2005 ([6]changes)
   11338 
   11339 References and Acknowledgements
   11340 
   11341    GCC used to stand for the GNU C Compiler, but since the compiler
   11342    supports several other languages aside from C, it now stands for the
   11343    GNU Compiler Collection.
   11344 
   11345    A list of [7]successful builds is updated as new information becomes
   11346    available.
   11347 
   11348    The GCC developers would like to thank the numerous people that have
   11349    contributed new features, improvements, bug fixes, and other changes as
   11350    well as test results to GCC. This [8]amazing group of volunteers is
   11351    what makes GCC successful.
   11352 
   11353    For additional information about GCC please refer to the [9]GCC project
   11354    web site or contact the [10]GCC development mailing list.
   11355 
   11356    To obtain GCC please use [11]our mirror sites, or [12]our version
   11357    control system.
   11358 
   11359 
   11360     For questions related to the use of GCC, please consult these web
   11361     pages and the [13]GCC manuals. If that fails, the
   11362     [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   11363     web pages and the development of GCC are welcome on our developer
   11364     list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public
   11365     archives.
   11366 
   11367    Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and
   11368    distribution of this entire article is permitted in any medium,
   11369    provided this notice is preserved.
   11370 
   11371    These pages are [18]maintained by the GCC team. Last modified
   11372    2020-01-14[19].
   11373 
   11374 References
   11375 
   11376    1. http://www.gnu.org/
   11377    2. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4
   11378    3. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.3
   11379    4. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.2
   11380    5. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.1
   11381    6. http://gcc.gnu.org/gcc-4.0/changes.html
   11382    7. http://gcc.gnu.org/gcc-4.0/buildstat.html
   11383    8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   11384    9. http://gcc.gnu.org/index.html
   11385   10. mailto:gcc (a] gcc.gnu.org
   11386   11. http://gcc.gnu.org/mirrors.html
   11387   12. http://gcc.gnu.org/git.html
   11388   13. https://gcc.gnu.org/onlinedocs/
   11389   14. mailto:gcc-help (a] gcc.gnu.org
   11390   15. mailto:gcc (a] gcc.gnu.org
   11391   16. https://gcc.gnu.org/lists.html
   11392   17. https://www.fsf.org/
   11393   18. https://gcc.gnu.org/about.html
   11394   19. http://validator.w3.org/check/referer
   11395 ======================================================================
   11396 http://gcc.gnu.org/gcc-4.0/changes.html
   11397                              GCC 4.0 Release Series
   11398                         Changes, New Features, and Fixes
   11399 
   11400    The latest release in the 4.0 release series is [1]GCC 4.0.4.
   11401 
   11402 Caveats
   11403 
   11404      * GCC now generates location lists by default when compiling with
   11405        debug info and optimization.
   11406           + GDB 6.0 and older crashes when it sees location lists. GDB 6.1
   11407             or later is needed to debug binaries containing location
   11408             lists.
   11409           + When you are trying to view a value of a variable in a part of
   11410             a function where it has no location (for example when the
   11411             variable is no longer used and thus its location was used for
   11412             something else) GDB will say that it is not available.
   11413        You can disable generating location lists by -fno-var-tracking.
   11414      * GCC no longer accepts the -fwritable-strings option. Use named
   11415        character arrays when you need a writable string.
   11416      * The options -freduce-all-givs and -fmove-all-movables have been
   11417        discontinued. They were used to circumvent a shortcoming in the
   11418        heuristics of the old loop optimization code with respect to common
   11419        Fortran constructs. The new (tree) loop optimizer works differently
   11420        and doesn't need those work-arounds.
   11421      * The graph-coloring register allocator, formerly enabled by the
   11422        option -fnew-ra, has been discontinued.
   11423      * -I- has been deprecated. -iquote is meant to replace the need for
   11424        this option.
   11425      * The MIPS -membedded-pic and -mrnames options have been removed.
   11426      * All MIPS targets now require the GNU assembler. In particular, IRIX
   11427        configurations can no longer use the MIPSpro assemblers, although
   11428        they do still support the MIPSpro linkers.
   11429      * The SPARC option -mflat has been removed.
   11430      * English-language diagnostic messages will now use Unicode quotation
   11431        marks in UTF-8 locales. (Non-English messages already used the
   11432        quotes appropriate for the language in previous releases.) If your
   11433        terminal does not support UTF-8 but you are using a UTF-8 locale
   11434        (such locales are the default on many GNU/Linux systems) then you
   11435        should set LC_CTYPE=C in the environment to disable that locale.
   11436        Programs that parse diagnostics and expect plain ASCII
   11437        English-language messages should set LC_ALL=C. See [2]Markus Kuhn's
   11438        explanation of Unicode quotation marks for more information.
   11439      * The specs file is no longer installed on most platforms. Most users
   11440        will be totally unaffected. However, if you are accustomed to
   11441        editing the specs file yourself, you will now have to use the
   11442        -dumpspecs option to generate the specs file, and then edit the
   11443        resulting file.
   11444 
   11445 General Optimizer Improvements
   11446 
   11447      * The [3]tree ssa branch has been merged. This merge has brought in a
   11448        completely new optimization framework based on a higher level
   11449        intermediate representation than the existing RTL representation.
   11450        Numerous new code transformations based on the new framework are
   11451        available in GCC 4.0, including:
   11452           + Scalar replacement of aggregates
   11453           + Constant propagation
   11454           + Value range propagation
   11455           + Partial redundancy elimination
   11456           + Load and store motion
   11457           + Strength reduction
   11458           + Dead store elimination
   11459           + Dead and unreachable code elimination
   11460           + [4]Autovectorization
   11461           + Loop interchange
   11462           + Tail recursion by accumulation
   11463        Many of these passes outperform their counterparts from previous
   11464        GCC releases.
   11465      * [5]Swing Modulo Scheduling (SMS). An RTL level instruction
   11466        scheduling optimization intended for loops that perform heavy
   11467        computations.
   11468 
   11469 New Languages and Language specific improvements
   11470 
   11471   C family
   11472 
   11473      * The sentinel attribute has been added to GCC. This function
   11474        attribute allows GCC to warn when variadic functions such as execl
   11475        are not NULL terminated. See the GCC manual for a complete
   11476        description of its behavior.
   11477      * Given __attribute__((alias("target"))) it is now an error if target
   11478        is not a symbol, defined in the same translation unit. This also
   11479        applies to aliases created by #pragma weak alias=target. This is
   11480        because it's meaningless to define an alias to an undefined symbol.
   11481        On Solaris, the native assembler would have caught this error, but
   11482        GNU as does not.
   11483 
   11484   C and Objective-C
   11485 
   11486      * The -Wstrict-aliasing=2 option has been added. This warning catches
   11487        all unsafe cases, but it may also give a warning for some cases
   11488        that are safe.
   11489      * The cast-as-lvalue, conditional-expression-as-lvalue and
   11490        compound-expression-as-lvalue extensions, which were deprecated in
   11491        3.3.4 and 3.4, have been removed.
   11492      * The -fwritable-strings option, which was deprecated in 3.4, has
   11493        been removed.
   11494      * #pragma pack() semantics have been brought closer to those used by
   11495        other compilers. This also applies to C++.
   11496      * Taking the address of a variable with register storage is invalid
   11497        in C. GCC now issues an error instead of a warning.
   11498      * Arrays of incomplete element type are invalid in C. GCC now issues
   11499        an error for such arrays. Declarations such as extern struct s x[];
   11500        (where struct s has not been defined) can be moved after the
   11501        definition of struct s. Function parameters declared as arrays of
   11502        incomplete type can instead be declared as pointers.
   11503 
   11504   C++
   11505 
   11506      * When compiling without optimizations (-O0), the C++ front end is
   11507        much faster than in any previous versions of GCC. Independent
   11508        testers have measured speed-ups up to 25% in real-world production
   11509        code, compared to the 3.4 family (which was already the fastest
   11510        version to date). Upgrading from older versions might show even
   11511        bigger improvements.
   11512      * ELF visibility attributes can now be applied to a class type, so
   11513        that it affects every member function of a class at once, without
   11514        having to specify each individually:
   11515 class __attribute__ ((visibility("hidden"))) Foo
   11516 {
   11517    int foo1();
   11518    void foo2();
   11519 };
   11520        The syntax is deliberately similar to the __declspec() system used
   11521        by Microsoft Windows based compilers, allowing cross-platform
   11522        projects to easily reuse their existing macro system for denoting
   11523        exports and imports. By explicitly marking internal classes never
   11524        used outside a binary as hidden, one can completely avoid PLT
   11525        indirection overheads during their usage by the compiler. You can
   11526        find out more about the advantages of this at
   11527        [6]https://www.akkadia.org/drepper/dsohowto.pdf
   11528      * The -fvisibility-inlines-hidden option has been added which marks
   11529        all inlineable functions as having hidden ELF visibility, thus
   11530        removing their symbol and typeinfo from the exported symbol table
   11531        of the output ELF binary. Using this option can reduce the exported
   11532        symbol count of template-heavy code by up to 40% with no code
   11533        change at all, thus notably improving link and load times for the
   11534        binary as well as a reduction in size of up to 10%. Also, check the
   11535        new [7]-fvisibility option.
   11536      * The compiler now uses the library interface specified by the [8]C++
   11537        ABI for thread-safe initialization of function-scope static
   11538        variables. Most users should leave this alone, but embedded
   11539        programmers may want to disable this by specifying
   11540        -fno-threadsafe-statics for a small savings in code size.
   11541      * Taking the address of an explicit register variable is no longer
   11542        supported. Note that C++ allows taking the address of variables
   11543        with register storage so this will continue to compile with a
   11544        warning. For example, assuming that r0 is a machine register:
   11545 register int foo asm ("r0");
   11546 register int bar;
   11547 &foo; // error, no longer accepted
   11548 &bar; // OK, with a warning
   11549      * G++ has an undocumented extension to virtual function covariancy
   11550        rules that allowed the overrider to return a type that was
   11551        implicitly convertable to the overridden function's return type.
   11552        For instance a function returning void * could be overridden by a
   11553        function returning T *. This is now deprecated and will be removed
   11554        in a future release.
   11555      * The G++ minimum and maximum operators (<? and >?) and their
   11556        compound forms (<?=) and >?=) have been deprecated and will be
   11557        removed in a future version. Code using these operators should be
   11558        modified to use std::min and std::max instead.
   11559      * Declaration of nested classes of class templates as friends are
   11560        supported:
   11561 template <typename T> struct A {
   11562   class B {};
   11563 };
   11564 class C {
   11565   template <typename T> friend class A<T>::B;
   11566 };
   11567        This complements the feature member functions of class templates as
   11568        friends introduced in GCC 3.4.0.
   11569      * When declaring a friend class using an unqualified name, classes
   11570        outside the innermost non-class scope are not searched:
   11571 class A;
   11572 namespace N {
   11573   class B {
   11574     friend class A;   // Refer to N::A which has not been declared yet
   11575                       // because name outside namespace N are not searched
   11576     friend class ::A; // Refer to ::A
   11577   };
   11578 }
   11579        Hiding the friend name until declaration is still not implemented.
   11580      * Friends of classes defined outside their namespace are correctly
   11581        handled:
   11582 namespace N {
   11583   class A;
   11584 }
   11585 class N::A {
   11586   friend class B; // Refer to N::B in GCC 4.0.0
   11587                   // but ::B in earlier versions of GCC
   11588 };
   11589 
   11590     Runtime Library (libstdc++)
   11591 
   11592      * Optimization work:
   11593           + Added efficient specializations of istream functions for char
   11594             and wchar_t.
   11595           + Further performance tuning of strings, in particular wrt
   11596             single-char append and getline.
   11597           + iter_swap - and therefore most of the mutating algorithms -
   11598             now makes an unqualified call to swap when the value_type of
   11599             the two iterators is the same.
   11600      * A large subset of the features in Technical Report 1 (TR1 for
   11601        short) is experimentally delivered (i.e., no guarantees about the
   11602        implementation are provided. In particular it is not promised that
   11603        the library will remain link-compatible when code using TR1 is
   11604        used):
   11605           + General utilities such as reference_wrapper and shared_ptr.
   11606           + Function objects, i.e., result_of, mem_fn, bind, function.
   11607           + Support for metaprogramming.
   11608           + New containers such as tuple, array, unordered_set,
   11609             unordered_map, unordered_multiset, unordered_multimap.
   11610      * As usual, many bugs have been fixed and LWG resolutions implemented
   11611        for the first time (e.g., DR 409).
   11612 
   11613   Java
   11614 
   11615      * In order to prevent naming conflicts with other implementations of
   11616        these tools, some GCJ binaries have been renamed:
   11617           + rmic is now grmic,
   11618           + rmiregistry is now grmiregistry, and
   11619           + jar is now fastjar.
   11620        In particular, these names were problematic for the jpackage.org
   11621        packaging conventions which install symlinks in /usr/bin that point
   11622        to the preferred versions of these tools.
   11623      * The -findirect-dispatch argument to the compiler now works and
   11624        generates code following a new "binary compatibility" ABI. Code
   11625        compiled this way follows the binary compatibility rules of the
   11626        Java Language Specification.
   11627      * libgcj now has support for using GCJ as a JIT, using the
   11628        gnu.gcj.jit family of system properties.
   11629      * libgcj can now find a shared library corresponding to the bytecode
   11630        representation of a class. See the documentation for the new
   11631        gcj-dbtool program, and the new gnu.gcj.precompiled.db.path system
   11632        property.
   11633      * There have been many improvements to the class library. Here are
   11634        some highlights:
   11635           + Much more of AWT and Swing exist.
   11636           + Many new packages and classes were added, including
   11637             java.util.regex, java.net.URI, javax.crypto,
   11638             javax.crypto.interfaces, javax.crypto.spec, javax.net,
   11639             javax.net.ssl, javax.security.auth,
   11640             javax.security.auth.callback, javax.security.auth.login,
   11641             javax.security.auth.x500, javax.security.sasl, org.ietf.jgss,
   11642             javax.imageio, javax.imageio.event, javax.imageio.spi,
   11643             javax.print, javax.print.attribute,
   11644             javax.print.attribute.standard, javax.print.event, and
   11645             javax.xml
   11646           + Updated SAX and DOM, and imported GNU JAXP
   11647 
   11648   Fortran
   11649 
   11650      * A new [9]Fortran front end has replaced the aging GNU Fortran 77
   11651        front end. The new front end supports Fortran 90 and Fortran 95. It
   11652        may not yet be as stable as the old Fortran front end.
   11653 
   11654   Ada
   11655 
   11656      * Ada (with tasking and Zero Cost Exceptions) is now available on
   11657        many more targets, including but not limited to: alpha-linux,
   11658        hppa-hpux, hppa-linux, powerpc-darwin, powerpc-linux, s390-linux,
   11659        s390x-linux, sparc-linux.
   11660      * Some of the new Ada 2005 features are now implemented like
   11661        Wide_Wide_Character and Ada.Containers.
   11662      * Many bugs have been fixed, tools and documentation improved.
   11663      * To compile Ada from the sources, install an older working Ada
   11664        compiler and then use --enable-languages=ada at configuration time,
   11665        since the Ada front end is not currently activated by default. See
   11666        the [10]Installing GCC for details.
   11667 
   11668 New Targets and Target Specific Improvements
   11669 
   11670   H8/300
   11671 
   11672      * The frame layout has changed. In the new layout, the prologue of a
   11673        function first saves registers and then allocate space for locals,
   11674        resulting in an 1% improvement on code size.
   11675 
   11676   IA-32/x86-64 (AMD64)
   11677 
   11678      * The acos, asin, drem, exp10, exp2, expm1, fmod, ilogb, log10,
   11679        log1p, log2, logb and tan mathematical builtins (and their float
   11680        and long double variants) are now implemented as inline x87
   11681        intrinsics when using -ffast-math.
   11682      * The ceil, floor, nearbyint, rint and trunc mathematical builtins
   11683        (and their float and long double variants) are now implemented as
   11684        inline x87 intrinsics when using -ffast-math.
   11685      * The x87's fsincos instruction is now used automatically with
   11686        -ffast-math when calculating both the sin and cos of the same
   11687        argument.
   11688      * Instruction selection for multiplication and division by constants
   11689        has been improved.
   11690 
   11691   IA-64
   11692 
   11693      * Floating point division, integer division and sqrt are now inlined,
   11694        resulting in significant performance improvements on some codes.
   11695 
   11696   MIPS
   11697 
   11698      * Division by zero checks now use conditional traps if the target
   11699        processor supports them. This decreases code size by one word per
   11700        division operation. The old behavior (branch and break) can be
   11701        obtained either at configure time by passing --with-divide=breaks
   11702        to configure or at runtime by passing -mdivide-breaks to GCC.
   11703      * Support for MIPS64 paired-single instructions has been added. It is
   11704        enabled by -mpaired-single and can be accessed using both the
   11705        target-independent vector extensions and new MIPS-specific built-in
   11706        functions.
   11707      * Support for the MIPS-3D ASE has been added. It is enabled by
   11708        -mips3d and provides new MIPS-3D-specific built-in functions.
   11709      * The -mexplicit-relocs option now supports static n64 code (as is
   11710        used, for example, in 64-bit linux kernels). -mexplicit-relocs
   11711        should now be feature-complete and is enabled by default when GCC
   11712        is configured to use a compatible assembler.
   11713      * Support for the NEC VR4130 series has been added. This support
   11714        includes the use of VR-specific instructions and a new VR4130
   11715        scheduler. Full VR4130 support can be selected with -march=vr4130
   11716        while code for any ISA can be tuned for the VR4130 using
   11717        -mtune=vr4130. There is also a new -mvr4130-align option that
   11718        produces better schedules at the cost of increased code size.
   11719      * Support for the Broadcom SB-1 has been extended. There is now an
   11720        SB-1 scheduler as well as support for the SB-1-specific
   11721        paired-single instructions. Full SB-1 support can be selected with
   11722        -march=sb1 while code for any ISA can be optimized for the SB-1
   11723        using -mtune=sb1.
   11724      * The compiler can now work around errata in R4000, R4400, VR4120 and
   11725        VR4130 processors. These workarounds are enabled by -mfix-r4000,
   11726        -mfix-r4400, -mfix-vr4120 and -mfix-vr4130 respectively. The VR4120
   11727        and VR4130 workarounds need binutils 2.16 or above.
   11728      * IRIX shared libraries are now installed into the standard library
   11729        directories: o32 libraries go into lib/, n32 libraries go into
   11730        lib32/ and n64 libraries go into lib64/.
   11731      * The compiler supports a new -msym32 option. It can be used to
   11732        optimize n64 code in which all symbols are known to have 32-bit
   11733        values.
   11734 
   11735   S/390 and zSeries
   11736 
   11737      * New command-line options help to generate code intended to run in
   11738        an environment where stack space is restricted, e.g. Linux kernel
   11739        code:
   11740           + -mwarn-framesize and -mwarn-dynamicstack trigger compile-time
   11741             warnings for single functions that require large or dynamic
   11742             stack frames.
   11743           + -mstack-size and -mstack-guard generate code that checks for
   11744             stack overflow at run time.
   11745           + -mpacked-stack generates code that reduces the stack frame
   11746             size of many functions by reusing unneeded parts of the stack
   11747             bias area.
   11748      * The -msoft-float option now ensures that generated code never
   11749        accesses floating point registers.
   11750      * The s390x-ibm-tpf target now fully supports C++, including
   11751        exceptions and threads.
   11752      * Various changes to improve performance of the generated code have
   11753        been implemented, including:
   11754           + GCC now uses sibling calls where possible.
   11755           + Condition code handling has been optimized, allowing GCC to
   11756             omit redundant comparisons in certain cases.
   11757           + The cost function guiding many optimizations has been refined
   11758             to more accurately represent the z900 and z990 processors.
   11759           + The ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL WITH BORROW
   11760             instructions are now used to avoid conditional branches in
   11761             certain cases.
   11762           + The back end now uses the LEGITIMIZE_RELOAD_ADDRESS feature to
   11763             optimize address arithmetic required to access large stack
   11764             frames.
   11765           + GCC now makes more efficient use of memory-to-memory type
   11766             instructions (MVC, CLC, ...).
   11767           + More precise tracking of special register use allows better
   11768             instruction scheduling, in particular of the function prologue
   11769             and epilogue sequences.
   11770           + The Java front end now generates inline code to implement
   11771             integer division, instead of calling library routines.
   11772 
   11773   SPARC
   11774 
   11775      * The options -mv8, -msparclite, -mcypress, -msupersparc, -mf930 and
   11776        -mf934 have been removed. They have been replaced with -mcpu=xxx.
   11777      * The internal model used to estimate the relative cost of each
   11778        instruction has been updated. It is expected to give better results
   11779        on recent UltraSPARC processors.
   11780      * Code generation for function prologues and epilogues has been
   11781        improved, resulting in better scheduling and allowing multiple exit
   11782        points in functions.
   11783      * Support for Sun's Visual Instruction Set (VIS) has been enhanced.
   11784        It is enabled by -mvis and provides new built-in functions for VIS
   11785        instructions on UltraSPARC processors.
   11786      * The option -mapp-regs has been turned on by default on Solaris too.
   11787 
   11788   NetWare
   11789 
   11790      * Novell NetWare (on ix86, no other hardware platform was ever really
   11791        supported by this OS) has been re-enabled and the ABI supported by
   11792        GCC has been brought into sync with that of MetroWerks CodeWarrior
   11793        (the ABI previously supported was that of some Unix systems, which
   11794        NetWare never tried to support).
   11795 
   11796 Obsolete Systems
   11797 
   11798    Support for a number of older systems has been declared obsolete in GCC
   11799    4.0. Unless there is activity to revive them, the next release of GCC
   11800    will have their sources permanently removed.
   11801 
   11802    All GCC ports for the following processor architectures have been
   11803    declared obsolete:
   11804      * Intel i860
   11805      * Ubicom IP2022
   11806      * National Semiconductor NS32K (ns32k)
   11807      * Texas Instruments TMS320C[34]x
   11808 
   11809    Also, those for some individual systems have been obsoleted:
   11810      * SPARC family
   11811           + SPARClite-based systems (sparclite-*-coff, sparclite-*-elf,
   11812             sparc86x-*-elf)
   11813           + OpenBSD 32-bit (sparc-*-openbsd*)
   11814 
   11815 Documentation improvements
   11816 
   11817 Other significant improvements
   11818 
   11819      * Location lists are now generated by default when compiling with
   11820        debug info and optimization. Location lists provide more accurate
   11821        debug info about locations of variables and they allow debugging
   11822        code compiled with -fomit-frame-pointer.
   11823      * The -fvisibility option has been added which allows the default ELF
   11824        visibility of all symbols to be set per compilation and the new
   11825        #pragma GCC visibility preprocessor command allows the setting of
   11826        default ELF visibility for a region of code. Using
   11827        -fvisibility=hidden especially in combination with the new
   11828        -fvisibility-inlines-hidden can yield substantial improvements in
   11829        output binary quality including avoiding PLT indirection overheads,
   11830        reduction of the exported symbol count by up to 60% (with resultant
   11831        improvements to link and load times), better scope for the
   11832        optimizer to improve code and up to a 20% reduction in binary size.
   11833        Using these options correctly yields a binary with a similar symbol
   11834        count to a Windows DLL.
   11835        Perhaps more importantly, this new feature finally allows (with
   11836        careful planning) complete avoidance of symbol clashes when
   11837        manually loading shared objects with RTLD_GLOBAL, thus finally
   11838        solving problems many projects such as python were forced to use
   11839        RTLD_LOCAL for (with its resulting issues for C++ correctness). You
   11840        can find more information about using these options at
   11841        [11]https://gcc.gnu.org/wiki/Visibility.
   11842      __________________________________________________________________
   11843 
   11844 GCC 4.0.1
   11845 
   11846    This is the [12]list of problem reports (PRs) from GCC's bug tracking
   11847    system that are known to be fixed in the 4.0.1 release. This list might
   11848    not be complete (that is, it is possible that some PRs that have been
   11849    fixed are not listed here).
   11850 
   11851 GCC 4.0.2
   11852 
   11853    This is the [13]list of problem reports (PRs) from GCC's bug tracking
   11854    system that are known to be fixed in the 4.0.2 release. This list might
   11855    not be complete (that is, it is possible that some PRs that have been
   11856    fixed are not listed here).
   11857 
   11858    Unfortunately, due to a release engineering failure, this release has a
   11859    regression on Solaris that will affect some C++ programs. We suggest
   11860    that Solaris users apply a [14]patch that corrects the problem. Users
   11861    who do not wish to apply the patch should explicitly link C++ programs
   11862    with the -pthreads option, even if they do not use threads. This
   11863    problem has been corrected in the current 4.0 branch sources and will
   11864    not be present in GCC 4.0.3.
   11865 
   11866 GCC 4.0.3
   11867 
   11868    Starting with this release, the function getcontext is recognized by
   11869    the compiler as having the same semantics as the setjmp function. In
   11870    particular, the compiler will ensure that all registers are dead before
   11871    calling such a function and will emit a warning about the variables
   11872    that may be clobbered after the second return from the function.
   11873 
   11874 GCC 4.0.4
   11875 
   11876    This is the [15]list of problem reports (PRs) from GCC's bug tracking
   11877    system that are known to be fixed in the 4.0.4 release. This list might
   11878    not be complete (that is, it is possible that some PRs that have been
   11879    fixed are not listed here).
   11880 
   11881    The 4.0.4 release is provided for those that require a high degree of
   11882    binary compatibility with previous 4.0.x releases. For most users, the
   11883    GCC team recommends that version 4.1.1 or later be used instead."
   11884 
   11885 
   11886     For questions related to the use of GCC, please consult these web
   11887     pages and the [16]GCC manuals. If that fails, the
   11888     [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   11889     web pages and the development of GCC are welcome on our developer
   11890     list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public
   11891     archives.
   11892 
   11893    Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and
   11894    distribution of this entire article is permitted in any medium,
   11895    provided this notice is preserved.
   11896 
   11897    These pages are [21]maintained by the GCC team. Last modified
   11898    2019-11-28[22].
   11899 
   11900 References
   11901 
   11902    1. http://gcc.gnu.org/gcc-4.0/changes.html#4.0.4
   11903    2. https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html
   11904    3. http://gcc.gnu.org/projects/tree-ssa/
   11905    4. http://gcc.gnu.org/projects/tree-ssa/vectorization.html
   11906    5. http://gcc.gnu.org/news/sms.html
   11907    6. https://www.akkadia.org/drepper/dsohowto.pdf
   11908    7. http://gcc.gnu.org/gcc-4.0/changes.html#visibility
   11909    8. https://itanium-cxx-abi.github.io/cxx-abi/
   11910    9. http://gcc.gnu.org/fortran/
   11911   10. https://gcc.gnu.org/install/
   11912   11. https://gcc.gnu.org/wiki/Visibility
   11913   12. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.1
   11914   13. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.2
   11915   14. https://gcc.gnu.org/ml/gcc-cvs/2005-09/msg00984.html
   11916   15. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.0.4
   11917   16. https://gcc.gnu.org/onlinedocs/
   11918   17. mailto:gcc-help (a] gcc.gnu.org
   11919   18. mailto:gcc (a] gcc.gnu.org
   11920   19. https://gcc.gnu.org/lists.html
   11921   20. https://www.fsf.org/
   11922   21. https://gcc.gnu.org/about.html
   11923   22. http://validator.w3.org/check/referer
   11924 ======================================================================
   11925 http://gcc.gnu.org/gcc-3.4/index.html
   11926                              GCC 3.4 Release Series
   11927 
   11928    (This release series is no longer supported.)
   11929 
   11930    May 26, 2006
   11931 
   11932    The [1]GNU project and the GCC developers are pleased to announce the
   11933    release of GCC 3.4.6.
   11934 
   11935    This release is a bug-fix release, containing fixes for regressions in
   11936    GCC 3.4.4 relative to previous releases of GCC. This is the last of the
   11937    3.4.x series.
   11938 
   11939    The GCC 3.4 release series includes numerous [2]new features,
   11940    improvements, bug fixes, and other changes, thanks to an [3]amazing
   11941    group of volunteers.
   11942 
   11943 Release History
   11944 
   11945    GCC 3.4.6
   11946           March 6, 2006 ([4]changes)
   11947 
   11948    GCC 3.4.5
   11949           November 30, 2005 ([5]changes)
   11950 
   11951    GCC 3.4.4
   11952           May 18, 2005 ([6]changes)
   11953 
   11954    GCC 3.4.3
   11955           November 4, 2004 ([7]changes)
   11956 
   11957    GCC 3.4.2
   11958           September 6, 2004 ([8]changes)
   11959 
   11960    GCC 3.4.1
   11961           July 1, 2004 ([9]changes)
   11962 
   11963    GCC 3.4.0
   11964           April 18, 2004 ([10]changes)
   11965 
   11966 References and Acknowledgements
   11967 
   11968    GCC used to stand for the GNU C Compiler, but since the compiler
   11969    supports several other languages aside from C, it now stands for the
   11970    GNU Compiler Collection.
   11971 
   11972    A list of [11]successful builds is updated as new information becomes
   11973    available.
   11974 
   11975    The GCC developers would like to thank the numerous people that have
   11976    contributed new features, improvements, bug fixes, and other changes as
   11977    well as test results to GCC. This [12]amazing group of volunteers is
   11978    what makes GCC successful.
   11979 
   11980    For additional information about GCC please refer to the [13]GCC
   11981    project web site or contact the [14]GCC development mailing list.
   11982 
   11983    To obtain GCC please use [15]our mirror sites, or [16]our version
   11984    control system.
   11985 
   11986 
   11987     For questions related to the use of GCC, please consult these web
   11988     pages and the [17]GCC manuals. If that fails, the
   11989     [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   11990     web pages and the development of GCC are welcome on our developer
   11991     list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public
   11992     archives.
   11993 
   11994    Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and
   11995    distribution of this entire article is permitted in any medium,
   11996    provided this notice is preserved.
   11997 
   11998    These pages are [22]maintained by the GCC team. Last modified
   11999    2020-01-14[23].
   12000 
   12001 References
   12002 
   12003    1. http://www.gnu.org/
   12004    2. http://gcc.gnu.org/gcc-3.4/changes.html
   12005    3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   12006    4. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6
   12007    5. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.5
   12008    6. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.4
   12009    7. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.3
   12010    8. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.2
   12011    9. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.1
   12012   10. http://gcc.gnu.org/gcc-3.4/changes.html
   12013   11. http://gcc.gnu.org/gcc-3.4/buildstat.html
   12014   12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   12015   13. http://gcc.gnu.org/index.html
   12016   14. mailto:gcc (a] gcc.gnu.org
   12017   15. http://gcc.gnu.org/mirrors.html
   12018   16. http://gcc.gnu.org/git.html
   12019   17. https://gcc.gnu.org/onlinedocs/
   12020   18. mailto:gcc-help (a] gcc.gnu.org
   12021   19. mailto:gcc (a] gcc.gnu.org
   12022   20. https://gcc.gnu.org/lists.html
   12023   21. https://www.fsf.org/
   12024   22. https://gcc.gnu.org/about.html
   12025   23. http://validator.w3.org/check/referer
   12026 ======================================================================
   12027 http://gcc.gnu.org/gcc-3.4/changes.html
   12028                              GCC 3.4 Release Series
   12029                         Changes, New Features, and Fixes
   12030 
   12031    The final release in the 3.4 release series is [1]GCC 3.4.6. The series
   12032    is now closed.
   12033 
   12034    GCC 3.4 has [2]many improvements in the C++ front end. Before reporting
   12035    a bug, please make sure it's really GCC, and not your code, that is
   12036    broken.
   12037 
   12038 Caveats
   12039 
   12040      * GNU Make is now required to build GCC.
   12041      * With -nostdinc the preprocessor used to ignore both standard
   12042        include paths and include paths contained in environment variables.
   12043        It was neither documented nor intended that environment variable
   12044        paths be ignored, so this has been corrected.
   12045      * GCC no longer accepts the options -fvolatile, -fvolatile-global and
   12046        -fvolatile-static. It is unlikely that they worked correctly in any
   12047        3.x release.
   12048      * GCC no longer ships <varargs.h>. Use <stdarg.h> instead.
   12049      * Support for all the systems [3]obsoleted in GCC 3.3 has been
   12050        removed from GCC 3.4. See below for a [4]list of systems which are
   12051        obsoleted in this release.
   12052      * GCC now requires an ISO C90 (ANSI C89) C compiler to build. K&R C
   12053        compilers will not work.
   12054      * The implementation of the [5]MIPS ABIs has changed. As a result,
   12055        the code generated for certain MIPS targets will not be binary
   12056        compatible with earlier releases.
   12057      * In previous releases, the MIPS port had a fake "hilo" register with
   12058        the user-visible name accum. This register has been removed.
   12059      * The implementation of the [6]SPARC ABIs has changed. As a result,
   12060        the code generated will not be binary compatible with earlier
   12061        releases in certain cases.
   12062      * The configure option --enable-threads=pthreads has been removed;
   12063        use --enable-threads=posix instead, which should have the same
   12064        effect.
   12065      * Code size estimates used by inlining heuristics for C, Objective-C,
   12066        C++ and Java have been redesigned significantly. As a result the
   12067        parameters of -finline-insns, --param max-inline-insns-single and
   12068        --param max-inline-insns-auto need to be reconsidered.
   12069      * --param max-inline-slope and --param min-inline-insns have been
   12070        removed; they are not needed for the new bottom-up inlining
   12071        heuristics.
   12072      * The new unit-at-a-time compilation scheme has several compatibility
   12073        issues:
   12074           + The order in which functions, variables, and top-level asm
   12075             statements are emitted may have changed. Code relying on some
   12076             particular ordering needs to be updated. The majority of such
   12077             top-level asm statements can be replaced by section
   12078             attributes.
   12079           + Unreferenced static variables and functions are removed. This
   12080             may result in undefined references when an asm statement
   12081             refers to the variable/function directly. In that case either
   12082             the variable/function shall be listed in asm statement operand
   12083             or in the case of top-level asm statements the attribute used
   12084             shall be used to force function/variable to be always output
   12085             and considered as a possibly used by unknown code.
   12086             For variables the attribute is accepted only by GCC 3.4 and
   12087             newer, while for earlier versions it is sufficient to use
   12088             unused to silence warnings about the variables not being
   12089             referenced. To keep code portable across different GCC
   12090             versions, you can use appropriate preprocessor conditionals.
   12091           + Static functions now can use non-standard passing conventions
   12092             that may break asm statements calling functions directly.
   12093             Again the attribute used shall be used to prevent this
   12094             behavior.
   12095        As a temporary workaround, -fno-unit-at-a-time can be used, but
   12096        this scheme may not be supported by future releases of GCC.
   12097      * GCC 3.4 automatically places zero-initialized variables in the .bss
   12098        section on some operating systems. Versions of GNU Emacs up to (and
   12099        including) 21.3 will not work correctly when using this
   12100        optimization; you can use -fno-zero-initialized-in-bss to disable
   12101        it.
   12102      * If GCC 3.4 is configured with --enable-threads=posix (the default
   12103        on most targets that support pthreads) then _REENTRANT will be
   12104        defined unconditionally by some libstdc++ headers. C++ code which
   12105        relies on that macro to detect whether multi-threaded code is being
   12106        compiled might change in meaning, possibly resulting in linker
   12107        errors for single-threaded programs. Affected users of [7]Boost
   12108        should compile single-threaded code with -DBOOST_DISABLE_THREADS.
   12109        See Bugzilla for [8]more information.
   12110 
   12111 General Optimizer Improvements
   12112 
   12113      * Usability of the profile feedback and coverage testing has been
   12114        improved.
   12115           + Performance of profiled programs has been improved by faster
   12116             profile merging code.
   12117           + Better use of the profile feedback for optimization (loop
   12118             unrolling and loop peeling).
   12119           + File locking support allowing fork() calls and parallel runs
   12120             of profiled programs.
   12121           + Coverage file format has been redesigned.
   12122           + gcov coverage tool has been improved.
   12123           + make profiledbootstrap available to build a faster compiler.
   12124             Experiments made on i386 hardware showed an 11% speedup on -O0
   12125             and a 7.5% speedup on -O2 compilation of a [9]large C++
   12126             testcase.
   12127           + New value profiling pass enabled via -fprofile-values
   12128           + New value profile transformations pass enabled via -fvpt aims
   12129             to optimize some code sequences by exploiting knowledge about
   12130             value ranges or other properties of the operands. At the
   12131             moment a conversion of expensive divisions into cheaper
   12132             operations has been implemented.
   12133           + New -fprofile-generate and -fprofile-use command-line options
   12134             to simplify the use of profile feedback.
   12135      * A new unit-at-a-time compilation scheme for C, Objective-C, C++ and
   12136        Java which is enabled via -funit-at-a-time (and implied by -O2). In
   12137        this scheme a whole file is parsed first and optimized later. The
   12138        following basic inter-procedural optimizations are implemented:
   12139           + Removal of unreachable functions and variables
   12140           + Discovery of local functions (functions with static linkage
   12141             whose address is never taken)
   12142           + On i386, these local functions use register parameter passing
   12143             conventions.
   12144           + Reordering of functions in topological order of the call graph
   12145             to enable better propagation of optimizing hints (such as the
   12146             stack alignments needed by functions) in the back end.
   12147           + Call graph based out-of-order inlining heuristics which allows
   12148             to limit overall compilation unit growth (--param
   12149             inline-unit-growth).
   12150        Overall, the unit-at-a-time scheme produces a 1.3% improvement for
   12151        the SPECint2000 benchmark on the i386 architecture (AMD Athlon
   12152        CPU).
   12153      * More realistic code size estimates used by inlining for C,
   12154        Objective-C, C++ and Java. The growth of large functions can now be
   12155        limited via --param large-function-insns and --param
   12156        large-function-growth.
   12157      * A new cfg-level loop optimizer pass replaces the old loop unrolling
   12158        pass and adds two other loop transformations -- loop peeling and
   12159        loop unswitching -- and also uses the profile feedback to limit
   12160        code growth. (The three optimizations are enabled by
   12161        -funroll-loops, -fpeel-loops and -funswitch-loops flags,
   12162        respectively).
   12163        The old loop unroller still can be enabled by -fold-unroll-loops
   12164        and may produce better code in some cases, especially when the
   12165        webizer optimization pass is not run.
   12166      * A new web construction pass enabled via -fweb (and implied by -O3)
   12167        improves the quality of register allocation, CSE, first scheduling
   12168        pass and some other optimization passes by avoiding re-use of
   12169        pseudo registers with non-overlapping live ranges. The pass almost
   12170        always improves code quality but does make debugging difficult and
   12171        thus is not enabled by default by -O2
   12172        The pass is especially effective as cleanup after code duplication
   12173        passes, such as the loop unroller or the tracer.
   12174      * Experimental implementations of superblock or trace scheduling in
   12175        the second scheduling pass can be enabled via
   12176        -fsched2-use-superblocks and -fsched2-use-traces, respectively.
   12177 
   12178 New Languages and Language specific improvements
   12179 
   12180   Ada
   12181 
   12182      * The Ada front end has been updated to include numerous bug fixes
   12183        and enhancements. These include:
   12184           + Improved project file support
   12185           + Additional set of warnings about potential wrong code
   12186           + Improved error messages
   12187           + Improved code generation
   12188           + Improved cross reference information
   12189           + Improved inlining
   12190           + Better run-time check elimination
   12191           + Better error recovery
   12192           + More efficient implementation of unbounded strings
   12193           + Added features in GNAT.Sockets, GNAT.OS_Lib, GNAT.Debug_Pools,
   12194             ...
   12195           + New GNAT.xxxx packages (e.g. GNAT.Strings,
   12196             GNAT.Exception_Action)
   12197           + New pragmas
   12198           + New -gnatS switch replacing gnatpsta
   12199           + Implementation of new Ada features (in particular limited
   12200             with, limited aggregates)
   12201 
   12202   C/Objective-C/C++
   12203 
   12204      * Precompiled headers are now supported. Precompiled headers can
   12205        dramatically speed up compilation of some projects. There are some
   12206        known defects in the current precompiled header implementation that
   12207        will result in compiler crashes in relatively rare situations.
   12208        Therefore, precompiled headers should be considered a "technology
   12209        preview" in this release. Read the manual for details about how to
   12210        use precompiled headers.
   12211      * File handling in the preprocessor has been rewritten. GCC no longer
   12212        gets confused by symlinks and hardlinks, and now has a correct
   12213        implementation of #import and #pragma once. These two directives
   12214        have therefore been un-deprecated.
   12215      * The undocumented extension that allowed C programs to have a label
   12216        at the end of a compound statement, which has been deprecated since
   12217        GCC 3.0, has been removed.
   12218      * The cast-as-lvalue extension has been removed for C++ and
   12219        deprecated for C and Objective-C. In particular, code like this:
   12220         int i;
   12221         (char) i = 5;
   12222 
   12223        or this:
   12224         char *p;
   12225         ((int *) p)++;
   12226 
   12227        is no longer accepted for C++ and will not be accepted for C and
   12228        Objective-C in a future version.
   12229      * The conditional-expression-as-lvalue extension has been deprecated
   12230        for C and Objective-C. In particular, code like this:
   12231         int a, b, c;
   12232         (a ? b : c) = 2;
   12233 
   12234        will not be accepted for C and Objective-C in a future version.
   12235      * The compound-expression-as-lvalue extension has been deprecated for
   12236        C and Objective-C. In particular, code like this:
   12237         int a, b;
   12238         (a, b) = 2;
   12239 
   12240        will not be accepted for C and Objective-C in a future version. A
   12241        possible non-intrusive workaround is the following:
   12242         (*(a, &b)) = 2;
   12243 
   12244      * Several [10]built-in functions such as __builtin_popcount for
   12245        counting bits, finding the highest and lowest bit in a word, and
   12246        parity have been added.
   12247      * The -fwritable-strings option has been deprecated and will be
   12248        removed.
   12249      * Many C math library functions are now recognized as built-ins and
   12250        optimized.
   12251      * The C, C++, and Objective-C compilers can now handle source files
   12252        written in any character encoding supported by the host C library.
   12253        The default input character set is taken from the current locale,
   12254        and may be overridden with the -finput-charset command line option.
   12255        In the future we will add support for inline encoding markers.
   12256 
   12257   C++
   12258 
   12259      * G++ is now much closer to full conformance to the ISO/ANSI C++
   12260        standard. This means, among other things, that a lot of invalid
   12261        constructs which used to be accepted in previous versions will now
   12262        be rejected. It is very likely that existing C++ code will need to
   12263        be fixed. This document lists some of the most common issues.
   12264      * A hand-written recursive-descent C++ parser has replaced the
   12265        YACC-derived C++ parser from previous GCC releases. The new parser
   12266        contains much improved infrastructure needed for better parsing of
   12267        C++ source codes, handling of extensions, and clean separation
   12268        (where possible) between proper semantics analysis and parsing. The
   12269        new parser fixes many bugs that were found in the old parser.
   12270      * You must now use the typename and template keywords to disambiguate
   12271        dependent names, as required by the C++ standard.
   12272         struct K {
   12273           typedef int mytype_t;
   12274         };
   12275 
   12276         template <class T1> struct A {
   12277           template <class T2> struct B {
   12278               void callme(void);
   12279             };
   12280 
   12281           template <int N> void bar(void)
   12282           {
   12283             // Use 'typename' to tell the parser that T1::mytype_t names
   12284             //  a type. This is needed because the name is dependent (in
   12285             //  this case, on template parameter T1).
   12286             typename T1::mytype_t x;
   12287             x = 0;
   12288           }
   12289         };
   12290 
   12291         template <class T> void template_func(void)
   12292         {
   12293           // Use 'template' to prefix member templates within
   12294           //  dependent types (a has type A<T>, which depends on
   12295           //  the template parameter T).
   12296           A<T> a;
   12297           a.template bar<0>();
   12298 
   12299           // Use 'template' to tell the parser that B is a nested
   12300           //  template class (dependent on template parameter T), and
   12301           //  'typename' because the whole A<T>::B<int> is
   12302           //  the name of a type (again, dependent).
   12303           typename A<T>::template B<int> b;
   12304           b.callme();
   12305         }
   12306 
   12307         void non_template_func(void)
   12308         {
   12309           // Outside of any template class or function, no names can be
   12310           //  dependent, so the use of the keyword 'typename' and 'template'
   12311           //  is not needed (and actually forbidden).
   12312           A<K> a;
   12313           a.bar<0>();
   12314           A<K>::B<float> b;
   12315           b.callme();
   12316         }
   12317      * In a template definition, unqualified names will no longer find
   12318        members of a dependent base (as specified by [temp.dep]/3 in the
   12319        C++ standard). For example,
   12320         template <typename T> struct B {
   12321           int m;
   12322           int n;
   12323           int f ();
   12324           int g ();
   12325         };
   12326         int n;
   12327         int g ();
   12328         template <typename T> struct C : B<T> {
   12329           void h ()
   12330           {
   12331             m = 0; // error
   12332             f ();  // error
   12333             n = 0; // ::n is modified
   12334             g ();  // ::g is called
   12335           }
   12336         };
   12337        You must make the names dependent, e.g. by prefixing them with
   12338        this->. Here is the corrected definition of C<T>::h,
   12339         template <typename T> void C<T>::h ()
   12340         {
   12341           this->m = 0;
   12342           this->f ();
   12343           this->n = 0
   12344           this->g ();
   12345         }
   12346        As an alternative solution (unfortunately not backwards compatible
   12347        with GCC 3.3), you may use using declarations instead of this->:
   12348         template <typename T> struct C : B<T> {
   12349           using B<T>::m;
   12350           using B<T>::f;
   12351           using B<T>::n;
   12352           using B<T>::g;
   12353           void h ()
   12354           {
   12355             m = 0;
   12356             f ();
   12357             n = 0;
   12358             g ();
   12359           }
   12360         };
   12361      * In templates, all non-dependent names are now looked up and bound
   12362        at definition time (while parsing the code), instead of later when
   12363        the template is instantiated. For instance:
   12364         void foo(int);
   12365 
   12366         template <int> struct A {
   12367           static void bar(void){
   12368             foo('a');
   12369           }
   12370         };
   12371 
   12372         void foo(char);
   12373 
   12374         int main()
   12375         {
   12376           A<0>::bar();    // Calls foo(int), used to call foo(char).
   12377         }
   12378 
   12379      * In an explicit instantiation of a class template, you must use
   12380        class or struct before the template-id:
   12381         template <int N>
   12382         class A {};
   12383 
   12384         template A<0>;         // error, not accepted anymore
   12385         template class A<0>;   // OK
   12386      * The "named return value" and "implicit typename" extensions have
   12387        been removed.
   12388      * Default arguments in function types have been deprecated and will
   12389        be removed.
   12390      * ARM-style name-injection of friend declarations has been deprecated
   12391        and will be removed. For example: struct S { friend void f(); };
   12392        void g() { f(); } will not be accepted by future versions of G++;
   12393        instead a declaration of "f" will need to be present outside of the
   12394        scope of "S".
   12395      * Covariant returns are implemented for all but varadic functions
   12396        that require an adjustment.
   12397      * When -pedantic is used, G++ now issues errors about spurious
   12398        semicolons. For example,
   12399         namespace N {}; // Invalid semicolon.
   12400         void f() {}; // Invalid semicolon.
   12401      * G++ no longer accepts attributes for a declarator after the
   12402        initializer associated with that declarator. For example,
   12403         X x(1) __attribute__((...));
   12404        is no longer accepted. Instead, use:
   12405         X x __attribute__((...)) (1);
   12406      * Inside the scope of a template class, the name of the class itself
   12407        can be treated as either a class or a template. So GCC used to
   12408        accept the class name as argument of type template, and template
   12409        template parameter. However this is not C++ standard compliant. Now
   12410        the name is not treated as a valid template template argument
   12411        unless you qualify the name by its scope. For example, the code
   12412        below no longer compiles.
   12413         template <template <class> class TT> class X {};
   12414         template <class T> class Y {
   12415           X<Y> x; // Invalid, Y is always a type template parameter.
   12416         };
   12417        The valid code for the above example is
   12418           X< ::Y> x; // Valid.
   12419        (Notice the space between < and : to prevent GCC to interpret this
   12420        as a digraph for [.)
   12421      * Friend declarations that refer to template specializations are
   12422        rejected if the template has not already been declared. For
   12423        example,
   12424         template <typename T>
   12425         class C {
   12426           friend void f<> (C&);
   12427         };
   12428        is rejected. You must first declare f as a template,
   12429         template <typename T>
   12430         void f(T);
   12431      * In case of friend declarations, every name used in the friend
   12432        declaration must be accessible at the point of that declaration.
   12433        Previous versions of G++ used to be less strict about this and
   12434        allowed friend declarations for private class members, for example.
   12435        See the ISO C++ Standard Committee's [11]defect report #209 for
   12436        details.
   12437      * Declaration of member functions of class templates as friends are
   12438        supported. For example,
   12439         template <typename T> struct A {
   12440           void f();
   12441         };
   12442         class C {
   12443           template <typename T> friend void A<T>::f();
   12444         };
   12445      * You must use template <> to introduce template specializations, as
   12446        required by the standard. For example,
   12447         template <typename T>
   12448         struct S;
   12449 
   12450         struct S<int> { };
   12451        is rejected. You must write,
   12452         template <> struct S<int> {};
   12453      * G++ used to accept code like this,
   12454         struct S {
   12455           int h();
   12456           void f(int i = g());
   12457           int g(int i = h());
   12458         };
   12459        This behavior is not mandated by the standard. Now G++ issues an
   12460        error about this code. To avoid the error, you must move the
   12461        declaration of g before the declaration of f. The default arguments
   12462        for g must be visible at the point where it is called.
   12463      * The C++ ABI Section 3.3.3 specifications for the array construction
   12464        routines __cxa_vec_new2 and __cxa_vec_new3 were changed to return
   12465        NULL when the allocator argument returns NULL. These changes are
   12466        incorporated into the libstdc++ runtime library.
   12467      * Using a name introduced by a typedef in a friend declaration or in
   12468        an explicit instantiation is now rejected, as specified by the ISO
   12469        C++ standard.
   12470         class A;
   12471         typedef A B;
   12472         class C {
   12473           friend class B;      // error, no typedef name here
   12474           friend B;            // error, friend always needs class/struct/enum
   12475           friend class A;      // OK
   12476         };
   12477 
   12478         template <int> class Q {};
   12479         typedef Q<0> R;
   12480         template class R;      // error, no typedef name here
   12481         template class Q<0>;   // OK
   12482      * When allocating an array with a new expression, GCC used to allow
   12483        parentheses around the type name. This is actually ill-formed and
   12484        it is now rejected:
   12485         int* a = new (int)[10];    // error, not accepted anymore
   12486         int* a = new int[10];      // OK
   12487      * When binding an rvalue of class type to a reference, the copy
   12488        constructor of the class must be accessible. For instance, consider
   12489        the following code:
   12490         class A
   12491         {
   12492         public:
   12493           A();
   12494 
   12495         private:
   12496           A(const A&);   // private copy ctor
   12497         };
   12498 
   12499         A makeA(void);
   12500         void foo(const A&);
   12501 
   12502         void bar(void)
   12503         {
   12504           foo(A());       // error, copy ctor is not accessible
   12505           foo(makeA());   // error, copy ctor is not accessible
   12506 
   12507           A a1;
   12508           foo(a1);        // OK, a1 is a lvalue
   12509         }
   12510        This might be surprising at first sight, especially since most
   12511        popular compilers do not correctly implement this rule ([12]further
   12512        details).
   12513      * When forming a pointer to member or a pointer to member function,
   12514        access checks for class visibility (public, protected, private) are
   12515        now performed using the qualifying scope of the name itself. This
   12516        is better explained with an example:
   12517         class A
   12518         {
   12519         public:
   12520           void pub_func();
   12521         protected:
   12522           void prot_func();
   12523         private:
   12524           void priv_func();
   12525         };
   12526 
   12527         class B : public A
   12528         {
   12529         public:
   12530           void foo()
   12531           {
   12532             &A::pub_func;   // OK, pub_func is accessible through A
   12533             &A::prot_func;  // error, cannot access prot_func through A
   12534             &A::priv_func;  // error, cannot access priv_func through A
   12535 
   12536             &B::pub_func;   // OK, pub_func is accessible through B
   12537             &B::prot_func;  // OK, can access prot_func through B (within B)
   12538             &B::priv_func;  // error, cannot access priv_func through B
   12539           }
   12540         };
   12541 
   12542     Runtime Library (libstdc++)
   12543 
   12544      * Optimization work:
   12545           + Streamlined streambuf, filebuf, separate synched with C
   12546             Standard I/O streambuf.
   12547           + All formatted I/O now uses cached locale information.
   12548           + STL optimizations (memory/speed for list, red-black trees as
   12549             used by sets and maps).
   12550           + More use of GCC builtins.
   12551           + String optimizations (avoid contention on
   12552             increment/decrement-and-test of the reference count in the
   12553             empty-string object, constructor from input_iterators
   12554             speedup).
   12555      * Static linkage size reductions.
   12556      * Large File Support (files larger than 2 GB on 32-bit systems).
   12557      * Wide character and variable encoding filebuf work (UTF-8, Unicode).
   12558      * Generic character traits.
   12559      * Also support wchar_t specializations on Mac OS 10.3.x, FreeBSD 5.x,
   12560        Solaris 2.7 and above, AIX 5.x, Irix 6.5.
   12561      * The allocator class is now standard-conformant, and two additional
   12562        extension allocators have been added, mt_alloc and
   12563        bitmap_allocator.
   12564      * PCH support: -include bits/stdc++.h (2x compile speedup).
   12565      * Rewrote __cxa_demangle with support for C++ style allocators.
   12566      * New debug modes for STL containers and iterators.
   12567      * Testsuite rewrite: five times as many tests, plus increasingly
   12568        sophisticated tests, including I/O, MT, multi-locale, wide and
   12569        narrow characters.
   12570      * Use current versions of GNU "autotools" for build/configuration.
   12571 
   12572   Objective-C
   12573 
   12574      * The Objective-C front end has been updated to include the numerous
   12575        bug fixes and enhancements previously available only in Apple's
   12576        version of GCC. These include:
   12577           + Structured exception (@try... @catch... @finally, @throw) and
   12578             synchronization (@synchronized) support. These are accessible
   12579             via the -fobjc-exceptions switch; as of this writing, they may
   12580             only be used in conjunction with -fnext-runtime on Mac OS X
   12581             10.3 and later. See [13]Options Controlling Objective-C
   12582             Dialect for more information.
   12583           + An overhaul of @encode logic. The C99 _Bool and C++ bool type
   12584             may now be encoded as 'B'. In addition, the back-end/codegen
   12585             dependencies have been removed.
   12586           + An overhaul of message dispatch construction, ensuring that
   12587             the various receiver types (and casts thereof) are handled
   12588             properly, and that correct diagnostics are issued.
   12589           + Support for "Zero-Link" (-fzero-link) and "Fix-and-Continue"
   12590             (-freplace-objc-classes) debugging modes, currently available
   12591             on Mac OS X 10.3 and later. See [14]Options Controlling
   12592             Objective-C Dialect for more information.
   12593           + Access to optimized runtime entry points (-fno-nil-receivers )
   12594             on the assumption that message receivers are never nil. This
   12595             is currently available on Mac OS X 10.3 and later. See
   12596             [15]Options Controlling Objective-C Dialect for more
   12597             information.
   12598 
   12599   Java
   12600 
   12601      * Compiling a .jar file will now cause non-.class entries to be
   12602        automatically compiled as resources.
   12603      * libgcj has been ported to Darwin.
   12604      * Jeff Sturm has adapted Jan Hubicka's call graph optimization code
   12605        to gcj.
   12606      * libgcj has a new gcjlib URL type; this lets URLClassLoader load
   12607        code from shared libraries.
   12608      * libgcj has been much more completely merged with [16]GNU Classpath.
   12609      * Class loading is now much more correct; in particular the caller's
   12610        class loader is now used when that is required.
   12611      * [17]Eclipse 2.x will run out of the box using gij.
   12612      * Parts of java.nio have been implemented. Direct and indirect
   12613        buffers work, as do fundamental file and socket operations.
   12614      * java.awt has been improved, though it is still not ready for
   12615        general use.
   12616      * The HTTP protocol handler now uses HTTP/1.1 and can handle the POST
   12617        method.
   12618      * The MinGW port has matured. Enhancements include socket timeout
   12619        support, thread interruption, improved Runtime.exec() handling and
   12620        support for accented characters in filenames.
   12621 
   12622   Fortran
   12623 
   12624      * Fortran improvements are listed in the [18]Fortran documentation.
   12625 
   12626 New Targets and Target Specific Improvements
   12627 
   12628   Alpha
   12629 
   12630      * Several [19]built-in functions have been added such as
   12631        __builtin_alpha_zap to allow utilizing the more obscure
   12632        instructions of the CPU.
   12633      * Parameter passing of complex arguments has changed to match the
   12634        ABI. This change is incompatible with previous GCC versions, but
   12635        does fix compatibility with the Tru64 compiler and several corner
   12636        cases where GCC was incompatible with itself.
   12637 
   12638   ARM
   12639 
   12640      * Nicolas Pitre has contributed his hand-coded floating-point support
   12641        code for ARM. It is both significantly smaller and faster than the
   12642        existing C-based implementation, even when building applications
   12643        for Thumb. The arm-elf configuration has been converted to use the
   12644        new code.
   12645      * Support for the Intel's iWMMXt architecture, a second generation
   12646        XScale processor, has been added. Enabled at run time with the
   12647        -mcpu=iwmmxt command line switch.
   12648      * A new ARM target has been added: arm-wince-pe. This is similar to
   12649        the arm-pe target, but it defaults to using the APCS32 ABI.
   12650      * The existing ARM pipeline description has been converted to the use
   12651        the [20]DFA processor pipeline model. There is not much change in
   12652        code performance, but the description is now [21]easier to
   12653        understand.
   12654      * Support for the Cirrus EP9312 Maverick floating point co-processor
   12655        added. Enabled at run time with the -mcpu=ep9312 command line
   12656        switch. Note however that the multilibs to support this chip are
   12657        currently disabled in gcc/config/arm/t-arm-elf, so if you want to
   12658        enable their production you will have to uncomment the entries in
   12659        that file.
   12660 
   12661   H8/300
   12662 
   12663      * Support for long long has been added.
   12664      * Support for saveall attribute has been added.
   12665      * Pavel Pisa contributed hand-written 32-bit-by-32-bit division code
   12666        for H8/300H and H8S, which is much faster than the previous
   12667        implementation.
   12668      * A lot of small performance improvements.
   12669 
   12670   IA-32/AMD64 (x86-64)
   12671 
   12672      * Tuning for K8 (AMD Opteron/Athlon64) core is available via
   12673        -march=k8 and -mcpu=k8.
   12674      * Scalar SSE code generation carefully avoids reformatting penalties,
   12675        hidden dependencies and minimizes the number of uops generated on
   12676        both Intel and AMD CPUs.
   12677      * Vector MMX and SSE operands are now passed in registers to improve
   12678        performance and match the argument passing convention used by the
   12679        Intel C++ Compiler. As a result it is not possible to call
   12680        functions accepting vector arguments compiled by older GCC version.
   12681      * Conditional jump elimination is now more aggressive on modern CPUs.
   12682      * The Athlon ports has been converted to use the DFA processor
   12683        pipeline description.
   12684      * Optimization of indirect tail calls is now possible in a similar
   12685        fashion as direct sibcall optimization.
   12686      * Further small performance improvements.
   12687      * -m128bit-long-double is now less buggy.
   12688      * __float128 support in 64-bit compilation.
   12689      * Support for data structures exceeding 2GB in 64-bit mode.
   12690      * -mcpu has been renamed to -mtune.
   12691 
   12692   IA-64
   12693 
   12694      * Tuning code for the Itanium 2 processor has been added. The
   12695        generation of code tuned for Itanium 2 (option -mtune=itanium2) is
   12696        enabled by default now. To generate code tuned for Itanium 1 the
   12697        option -mtune=itanium1 should be used.
   12698      * [22]DFA processor pipeline descriptions for the IA-64 processors
   12699        have been added. This resulted in about 3% improvement on the
   12700        SPECInt2000 benchmark for Itanium 2.
   12701      * Instruction bundling for the IA-64 processors has been rewritten
   12702        using the DFA pipeline hazard recognizer. It resulted in about 60%
   12703        compiler speedup on the SPECInt2000 C programs.
   12704 
   12705   M32R
   12706 
   12707      * Support for the M32R/2 processor has been added by Renesas.
   12708      * Support for an M32R GNU/Linux target and PIC code generation has
   12709        been added by Renesas.
   12710 
   12711   M68000
   12712 
   12713      * Bernardo Innocenti (Develer S.r.l.) has contributed the
   12714        m68k-uclinux target, based on former work done by Paul Dale
   12715        (SnapGear Inc.). Code generation for the ColdFire processors family
   12716        has been enhanced and extended to support the MCF 53xx and MCF 54xx
   12717        cores, integrating former work done by Peter Barada (Motorola).
   12718 
   12719   MIPS
   12720 
   12721     Processor-specific changes
   12722 
   12723      * Support for the RM7000 and RM9000 processors has been added. It can
   12724        be selected using the -march compiler option and should work with
   12725        any MIPS I (mips-*) or MIPS III (mips64-*) configuration.
   12726      * Support for revision 2 of the MIPS32 ISA has been added. It can be
   12727        selected with the command-line option -march=mips32r2.
   12728      * There is a new option, -mfix-sb1, to work around certain SB-1
   12729        errata.
   12730 
   12731     Configuration
   12732 
   12733      * It is possible to customize GCC using the following configure-time
   12734        options:
   12735           + --with-arch, which specifies the default value of the -march
   12736             option.
   12737           + --with-tune, which specifies the default value of the -mtune
   12738             option.
   12739           + --with-abi, which specifies the default ABI.
   12740           + --with-float=soft, which tells GCC to use software floating
   12741             point by default.
   12742           + --with-float=hard, which tells GCC to use hardware floating
   12743             point by default.
   12744      * A 64-bit GNU/Linux port has been added. The associated
   12745        configurations are mips64-linux-gnu and mips64el-linux-gnu.
   12746      * The 32-bit GNU/Linux port now supports Java.
   12747      * The IRIX 6 configuration now supports the o32 ABI and will build
   12748        o32 multilibs by default. This support is compatible with both
   12749        binutils and the SGI tools, but note that several features,
   12750        including debugging information and DWARF2 exception handling, are
   12751        only available when using the GNU assembler. Use of the GNU
   12752        assembler and linker (version 2.15 or above) is strongly
   12753        recommended.
   12754      * The IRIX 6 configuration now supports 128-bit long doubles.
   12755      * There are two new RTEMS-specific configurations, mips-rtems and
   12756        mipsel-rtems.
   12757      * There are two new *-elf configurations, mipsisa32r2-elf and
   12758        mipsisa32r2el-elf.
   12759 
   12760     General
   12761 
   12762      * Several [23]ABI bugs have been fixed. Unfortunately, these changes
   12763        will break binary compatibility with earlier releases.
   12764      * GCC can now use explicit relocation operators when generating
   12765        -mabicalls code. This behavior is controlled by -mexplicit-relocs
   12766        and can have several performance benefits. For example:
   12767           + It allows for more optimization of GOT accesses, including
   12768             better scheduling and redundancy elimination.
   12769           + It allows sibling calls to be implemented as jumps.
   12770           + n32 and n64 leaf functions can use a call-clobbered global
   12771             pointer instead of $28.
   12772           + The code to set up $gp can be removed from functions that
   12773             don't need it.
   12774      * A new option, -mxgot, allows the GOT to be bigger than 64k. This
   12775        option is equivalent to the assembler's -xgot option and should be
   12776        used instead of -Wa,-xgot.
   12777      * Frame pointer elimination is now supported when generating 64-bit
   12778        MIPS16 code.
   12779      * Inline block moves have been optimized to take more account of
   12780        alignment information.
   12781      * Many internal changes have been made to the MIPS port, mostly aimed
   12782        at reducing the reliance on assembler macros.
   12783 
   12784   PowerPC
   12785 
   12786      * GCC 3.4 releases have a number of fixes for PowerPC and PowerPC64
   12787        [24]ABI incompatibilities regarding the way parameters are passed
   12788        during functions calls. These changes may result in incompatibility
   12789        between code compiled with GCC 3.3 and GCC 3.4.
   12790 
   12791     PowerPC Darwin
   12792 
   12793      * Support for shared/dylib gcc libraries has been added. It is
   12794        enabled by default on powerpc-apple-darwin7.0.0 and up.
   12795      * Libgcj is enabled by default. On systems older than
   12796        powerpc-apple-darwin7.0.0 you need to install dlcompat.
   12797      * 128-bit IBM extended precision format support added for long
   12798        double.
   12799 
   12800     PowerPC64 GNU/Linux
   12801 
   12802      * By default, PowerPC64 GNU/Linux now uses natural alignment of
   12803        structure elements. The old four byte alignment for double, with
   12804        special rules for a struct starting with a double, can be chosen
   12805        with -malign-power. This change may result in incompatibility
   12806        between code compiled with GCC 3.3 and GCC 3.4.
   12807      * -mabi=altivec is now the default rather than -mabi=no-altivec.
   12808      * 128-bit IBM extended precision format support added for long
   12809        double.
   12810 
   12811   S/390 and zSeries
   12812 
   12813      * New command-line options allow to specify the intended execution
   12814        environment for generated code:
   12815           + -mesa/-mzarch allows to specify whether to generate code
   12816             running in ESA/390 mode or in z/Architecture mode (this is
   12817             applicable to 31-bit code only).
   12818           + -march allows to specify a minimum processor architecture
   12819             level (g5, g6, z900, or z990).
   12820           + -mtune allows to specify which processor to tune for.
   12821      * It is possible to customize GCC using the following configure-time
   12822        options:
   12823           + --with-mode, which specifies whether to default to assuming
   12824             ESA/390 or z/Architecture mode.
   12825           + --with-arch, which specifies the default value of the -march
   12826             option.
   12827           + --with-tune, which specifies the default value of the -mtune
   12828             option.
   12829      * Support for the z990 processor has been added, and can be selected
   12830        using -march=z990 or -mtune=z990. This includes instruction
   12831        scheduling tuned for the superscalar instruction pipeline of the
   12832        z990 processor as well as support for all new instructions provided
   12833        by the long-displacement facility.
   12834      * Support to generate 31-bit code optimized for zSeries processors
   12835        (running in ESA/390 or in z/Architecture mode) has been added. This
   12836        can be selected using -march=z900 and -mzarch respectively.
   12837      * Instruction scheduling for the z900 and z990 processors now uses
   12838        the DFA pipeline hazard recognizer.
   12839      * GCC no longer generates code to maintain a stack backchain,
   12840        previously used to generate stack backtraces for debugging
   12841        purposes. As replacement that does not incur runtime overhead,
   12842        DWARF-2 call frame information is provided by GCC; this is
   12843        supported by GDB 6.1. The old behavior can be restored using the
   12844        -mbackchain option.
   12845      * The stack frame size of functions may now exceed 2 GB in 64-bit
   12846        code.
   12847      * A port for the 64-bit IBM TPF operating system has been added; the
   12848        configuration is s390x-ibm-tpf. This configuration is supported as
   12849        cross-compilation target only.
   12850      * Various changes to improve the generated code have been
   12851        implemented, including:
   12852           + GCC now uses the MULTIPLY AND ADD and MULTIPLY AND SUBTRACT
   12853             instructions to significantly speed up many floating-point
   12854             applications.
   12855           + GCC now uses the ADD LOGICAL WITH CARRY and SUBTRACT LOGICAL
   12856             WITH BORROW instructions to speed up long long arithmetic.
   12857           + GCC now uses the SEARCH STRING instruction to implement
   12858             strlen().
   12859           + In many cases, function call overhead for 31-bit code has been
   12860             reduced by placing the literal pool after the function code
   12861             instead of after the function prolog.
   12862           + Register 14 is no longer reserved in 64-bit code.
   12863           + Handling of global register variables has been improved.
   12864 
   12865   SPARC
   12866 
   12867      * The option -mflat is deprecated.
   12868      * Support for large (> 2GB) frames has been added to the 64-bit port.
   12869      * Several [25]ABI bugs have been fixed. Unfortunately, these changes
   12870        will break binary compatibility with earlier releases.
   12871      * The default debugging format has been switched from STABS to
   12872        DWARF-2 for 32-bit code on Solaris 7 and later. DWARF-2 is already
   12873        the default debugging format for 64-bit code on Solaris.
   12874 
   12875   SuperH
   12876 
   12877      * Support for the SH2E processor has been added. Enabled at run time
   12878        with the -m2e command line switch, or at configure time by
   12879        specifying sh2e as the machine part of the target triple.
   12880 
   12881   V850
   12882 
   12883      * Support for the Mitsubishi V850E1 processor has been added. This is
   12884        a variant of the V850E processor with some additional debugging
   12885        instructions.
   12886 
   12887   Xtensa
   12888 
   12889      * Several ABI bugs have been fixed. Unfortunately, these changes
   12890        break binary compatibility with earlier releases.
   12891           + For big-endian processors, the padding of aggregate return
   12892             values larger than a word has changed. If the size of an
   12893             aggregate return value is not a multiple of 32 bits, previous
   12894             versions of GCC inserted padding in the most-significant bytes
   12895             of the first return value register. Aggregates larger than a
   12896             word are now padded in the least-significant bytes of the last
   12897             return value register used. Aggregates smaller than a word are
   12898             still padded in the most-significant bytes. The return value
   12899             padding has not changed for little-endian processors.
   12900           + Function arguments with 16-byte alignment are now properly
   12901             aligned.
   12902           + The implementation of the va_list type has changed. A va_list
   12903             value created by va_start from a previous release cannot be
   12904             used with va_arg from this release, or vice versa.
   12905      * More processor configuration options for Xtensa processors are
   12906        supported:
   12907           + the ABS instruction is now optional;
   12908           + the ADDX* and SUBX* instructions are now optional;
   12909           + an experimental CONST16 instruction can be used to synthesize
   12910             constants instead of loading them from constant pools.
   12911        These and other Xtensa processor configuration options can no
   12912        longer be enabled or disabled by command-line options; the
   12913        processor configuration must be specified by the xtensa-config.h
   12914        header file when building GCC. Additionally, the
   12915        -mno-serialize-volatile option is no longer supported.
   12916 
   12917 Obsolete Systems
   12918 
   12919    Support for a number of older systems has been declared obsolete in GCC
   12920    3.4. Unless there is activity to revive them, the next release of GCC
   12921    will have their sources permanently removed.
   12922 
   12923    All configurations of the following processor architectures have been
   12924    declared obsolete:
   12925      * Mitsubishi D30V, d30v-*
   12926      * AT&T DSP1600 and DSP1610, dsp16xx-*
   12927      * Intel 80960, i960
   12928 
   12929    Also, some individual systems have been obsoleted:
   12930      * ARM Family
   12931           + Support for generating code for operation in APCS/26 mode
   12932             (-mapcs-26).
   12933      * IBM ESA/390
   12934           + "Bigfoot" port, i370-*. (The other port, s390-*, is actively
   12935             maintained and supported.)
   12936      * Intel 386 family
   12937           + MOSS, i?86-moss-msdos and i?86-*-moss*
   12938           + NCR 3000 running System V r.4, i?86-ncr-sysv4*
   12939           + FreeBSD with a.out object format, i?86-*-freebsd*aout* and
   12940             i?86-*-freebsd2*
   12941           + GNU/Linux with a.out object format, i?86-linux*aout*
   12942           + GNU/Linux with libc5, a.k.a. glibc1, i?86-linux*libc1*
   12943           + Interix versions before Interix 3, i?86-*-interix
   12944           + Mach microkernel, i?86-mach*
   12945           + SCO UnixWare with UDK, i?86-*-udk*
   12946           + Generic System V releases 1, 2, and 3, i?86-*-sysv[123]*
   12947           + VSTa microkernel, i386-*-vsta
   12948      * Motorola M68000 family
   12949           + HPUX, m68k-hp-hpux* and m68000-hp-hpux*
   12950           + NetBSD with a.out object format (before NetBSD 1.4),
   12951             m68k-*-*-netbsd* except m68k-*-*-netbsdelf*
   12952           + Generic System V r.4, m68k-*-sysv4*
   12953      * VAX
   12954           + Generic VAX, vax-*-* (This is generic VAX only; we have not
   12955             obsoleted any VAX triples for specific operating systems.)
   12956 
   12957 Documentation improvements
   12958 
   12959 Other significant improvements
   12960 
   12961      * The build system has undergone several significant cleanups.
   12962        Subdirectories will only be configured if they are being built, and
   12963        all subdirectory configures are run from the make command. The top
   12964        level has been autoconfiscated.
   12965      * Building GCC no longer writes to its source directory. This should
   12966        help those wishing to share a read-only source directory over NFS
   12967        or build from a CD. The exceptions to this feature are if you
   12968        configure with either --enable-maintainer-mode or
   12969        --enable-generated-files-in-srcdir.
   12970      * The -W warning option has been renamed to -Wextra, which is more
   12971        easily understood. The older spelling will be retained for
   12972        backwards compatibility.
   12973      * Substantial improvements in compile time have been made,
   12974        particularly for non-optimizing compilations.
   12975      __________________________________________________________________
   12976 
   12977 GCC 3.4.0
   12978 
   12979   Bug Fixes
   12980 
   12981    A vast number of bugs have been fixed in 3.4.0, too many to publish a
   12982    complete list here. [26]Follow this link to query the Bugzilla database
   12983    for the list of over 900 bugs fixed in 3.4.0. This is the list of all
   12984    bugs marked as resolved and fixed in 3.4.0 that are not flagged as 3.4
   12985    regressions.
   12986      __________________________________________________________________
   12987 
   12988 GCC 3.4.1
   12989 
   12990   Bug Fixes
   12991 
   12992    This section lists the problem reports (PRs) from GCC's bug tracking
   12993    system that are known to be fixed in the 3.4.1 release. This list might
   12994    not be complete (that is, it is possible that some PRs that have been
   12995    fixed are not listed here).
   12996 
   12997     Bootstrap failures
   12998 
   12999      * [27]10129 Ada bootstrap fails on PPC-Darwin - invalid assembler
   13000        emitted - PIC related
   13001      * [28]14576 [ARM] ICE in libiberty when building gcc-3.4 for arm-elf
   13002      * [29]14760 A bug in configure.in prevents using both
   13003        --program-suffix and --program-prefix
   13004      * [30]14671 [hppa64] bootstrap fails: ICE in
   13005        save_call_clobbered_regs, in caller_save.c
   13006      * [31]15093 [alpha][Java] make bootstrap fails to configure libffi on
   13007        Alpha
   13008      * [32]15178 Solaris 9/x86 fails linking after stage 3
   13009 
   13010     Multi-platform internal compiler errors (ICEs)
   13011 
   13012      * [33]12753 (preprocessor) Memory corruption in preprocessor on bad
   13013        input
   13014      * [34]13985 ICE in gcc.c-torture/compile/930621-1.c
   13015      * [35]14810 (c++) tree check failures with invalid code involving
   13016        templates
   13017      * [36]14883 (c++) ICE on invalid code, in cp_parser_lookup_name, in
   13018        cp/parser.c
   13019      * [37]15044 (c++) ICE on syntax error, template header
   13020      * [38]15057 (c++) Compiling of conditional value throw constructs
   13021        cause a segmentation violation
   13022      * [39]15064 (c++) typeid of template parameter gives ICE
   13023      * [40]15142 (c++) ICE when passing a string where a char* is expected
   13024        in a throw statement
   13025      * [41]15159 ICE in rtl_verify_flow_info_1
   13026      * [42]15165 (c++) ICE in instantiate_template
   13027      * [43]15193 Unary minus using pointer to V4SF vector causes
   13028        -fforce-mem to exhaust all memory
   13029      * [44]15209 (c++) Runs out of memory with packed structs
   13030      * [45]15227 (c++) Trouble with invalid function definition
   13031      * [46]15285 (c++) instantiate_type ICE when forming pointer to
   13032        template function
   13033      * [47]15299 (c++) ICE in resolve_overloaded_unification
   13034      * [48]15329 (c++) ICE on constructor of member template
   13035      * [49]15550 ICE in extract_insn, in recog.c
   13036      * [50]15554 (c++) ICE in tsubst_copy, in cp/pt.c
   13037      * [51]15640 (c++) ICE on invalid code in arg_assoc, in
   13038        cp/name-lookup.c
   13039      * [52]15666 [unit-at-a-time] Gcc abort on valid code
   13040      * [53]15696 (c++) ICE with bad pointer-to-member code
   13041      * [54]15701 (c++) ICE with friends and template template parameter
   13042      * [55]15761 ICE in do_SUBST, in combine.c
   13043      * [56]15829 (c++) ICE on Botan-1.3.13 due to -funroll-loops
   13044 
   13045     Ada
   13046 
   13047      * [57]14538 All RTEMS targets broken for gnat
   13048 
   13049     C front end
   13050 
   13051      * [58]12391 missing warning about assigning to an incomplete type
   13052      * [59]14649 atan(1.0) should not be a constant expression
   13053      * [60]15004 [unit-at-a-time] no warning for unused paramater in
   13054        static function
   13055      * [61]15749 --pedantic-errors behaves differently from --pedantic
   13056        with C-compiler on GNU/Linux
   13057 
   13058     C++ compiler and library
   13059 
   13060      * [62]10646 non-const reference is incorrectly matched in a "const T"
   13061        partial specialization
   13062      * [63]12077 wcin.rdbuf()->in_avail() return value too high
   13063      * [64]13598 enc_filebuf doesn't work
   13064      * [65]14211 const_cast returns lvalue but should be rvalue
   13065      * [66]14220 num_put::do_put() undesired float/double behavior
   13066      * [67]14245 problem with user-defined allocators in std::basic_string
   13067      * [68]14340 libstdc++ Debug mode: failure to convert iterator to
   13068        const_iterator
   13069      * [69]14600 __gnu_cxx::stdio_sync_filebuf should expose internal
   13070        FILE*
   13071      * [70]14668 no warning anymore for reevaluation of declaration
   13072      * [71]14775 LFS (large file support) tests missing
   13073      * [72]14821 Duplicate namespace alias declaration should not conflict
   13074      * [73]14930 Friend declaration ignored
   13075      * [74]14932 cannot use offsetof to get offsets of array elements in
   13076        g++ 3.4.0
   13077      * [75]14950 [non unit-at-a-time] always_inline does not mix with
   13078        templates and -O0
   13079      * [76]14962 g++ ignores #pragma redefine_extname
   13080      * [77]14975 Segfault on low-level write error during imbue
   13081      * [78]15002 Linewise stream input is unusably slow (std::string slow)
   13082      * [79]15025 compiler accepts redeclaration of template as
   13083        non-template
   13084      * [80]15046 [arm] Math functions misdetected by cross configuration
   13085      * [81]15069 a bit test on a variable of enum type is miscompiled
   13086      * [82]15074 g++ -lsupc++ still links against libstdc++
   13087      * [83]15083 spurious "statement has no effect" warning
   13088      * [84]15096 parse error with templates and pointer to const member
   13089      * [85]15287 combination of operator[] and operator .* fails in
   13090        templates
   13091      * [86]15317 __attribute__ unused in first parameter of constructor
   13092        gives error
   13093      * [87]15337 sizeof on incomplete type diagnostic
   13094      * [88]15361 bitset<>::_Find_next fails
   13095      * [89]15412 _GLIBCXX_ symbols symbols defined and used in different
   13096        namespaces
   13097      * [90]15427 valid code results in incomplete type error
   13098      * [91]15471 Incorrect member pointer offsets in anonymous
   13099        structs/unions
   13100      * [92]15503 nested template problem
   13101      * [93]15507 compiler hangs while laying out union
   13102      * [94]15542 operator & and template definitions
   13103      * [95]15565 SLES9: leading + sign for unsigned int with showpos
   13104      * [96]15625 friend defined inside a template fails to find static
   13105        function
   13106      * [97]15629 Function templates, overloads, and friend name injection
   13107      * [98]15742 'noreturn' attribute ignored in method of template
   13108        functions.
   13109      * [99]15775 Allocator::pointer consistently ignored
   13110      * [100]15821 Duplicate namespace alias within namespace rejected
   13111      * [101]15862 'enum yn' fails (confict with undeclared builtin)
   13112      * [102]15875 rejects pointer to member in template
   13113      * [103]15877 valid code using templates and anonymous enums is
   13114        rejected
   13115      * [104]15947 Puzzling error message for wrong destructor declaration
   13116        in template class
   13117      * [105]16020 cannot copy __gnu_debug::bitset
   13118      * [106]16154 input iterator concept too restrictive
   13119      * [107]16174 deducing top-level consts
   13120 
   13121     Java
   13122 
   13123      * [108]14315 Java compiler is not parallel make safe
   13124 
   13125     Fortran
   13126 
   13127      * [109]15151 [g77] incorrect logical i/o in 64-bit mode
   13128 
   13129     Objective-C
   13130 
   13131      * [110]7993 private variables cannot be shadowed in subclasses
   13132 
   13133     Optimization bugs
   13134 
   13135      * [111]15228 useless copies of floating point operands
   13136      * [112]15345 [non-unit-at-a-time] unreferenced nested inline
   13137        functions not optimized away
   13138      * [113]15945 Incorrect floating point optimization
   13139      * [114]15526 ftrapv aborts on 0 * (-1)
   13140      * [115]14690 Miscompiled POOMA tests
   13141      * [116]15112 GCC generates code to write to unchanging memory
   13142 
   13143     Preprocessor
   13144 
   13145      * [117]15067 Minor glitch in the source of cpp
   13146 
   13147     Main driver program bugs
   13148 
   13149      * [118]1963 collect2 interprets -oldstyle_liblookup as -o
   13150        ldstyle_liblookup
   13151 
   13152     x86-specific (Intel/AMD)
   13153 
   13154      * [119]15717 Error: can't resolve `L0' {*ABS* section} - `xx' {*UND*
   13155        section}
   13156 
   13157     HPPA-specific
   13158 
   13159      * [120]14782 GCC produces an unaligned data access at -O2
   13160      * [121]14828 FAIL: gcc.c-torture/execute/20030408-1.c execution, -O2
   13161      * [122]15202 ICE in reload_cse_simplify_operands, in postreload.c
   13162 
   13163     IA64-specific
   13164 
   13165      * [123]14610 __float80 constants incorrectly emitted
   13166      * [124]14813 init_array sections are initialized in the wrong order
   13167      * [125]14857 GCC segfault on duplicated asm statement
   13168      * [126]15598 Gcc 3.4 ICE on valid code
   13169      * [127]15653 Gcc 3.4 ICE on valid code
   13170 
   13171     MIPS-specific
   13172 
   13173      * [128]15189 wrong filling of delay slot with -march=mips1 -G0
   13174        -mno-split-addresses -mno-explicit-relocs
   13175      * [129]15331 Assembler error building gnatlib on IRIX 6.5 with GNU as
   13176        2.14.91
   13177      * [130]16144 Bogus reference to __divdf3 when -O1
   13178      * [131]16176 Miscompilation of unaligned data in MIPS backend
   13179 
   13180     PowerPC-specific
   13181 
   13182      * [132]11591 ICE in gcc.dg/altivec-5.c
   13183      * [133]12028 powerpc-eabispe produces bad sCOND operation
   13184      * [134]14478 rs6000 geu/ltu patterns generate incorrect code
   13185      * [135]14567 long double and va_arg complex args
   13186      * [136]14715 Altivec stack layout may overlap gpr save with stack
   13187        temps
   13188      * [137]14902 (libstdc++) Stream checking functions fail when -pthread
   13189        option is used.
   13190      * [138]14924 Compiler ICE on valid code
   13191      * [139]14960 -maltivec affects vector return with -mabi=no-altivec
   13192      * [140]15106 vector varargs failure passing from altivec to
   13193        non-altivec code for -m32
   13194      * [141]16026 ICE in function.c:4804, assign_parms, when -mpowerpc64 &
   13195        half-word operation
   13196      * [142]15191 -maltivec -mabi=no-altivec results in mis-aligned lvx
   13197        and stvx
   13198      * [143]15662 Segmentation fault when an exception is thrown - even if
   13199        try and catch are specified
   13200 
   13201     s390-specific
   13202 
   13203      * [144]15054 Bad code due to overlapping stack temporaries
   13204 
   13205     SPARC-specific
   13206 
   13207      * [145]15783 ICE with union assignment in 64-bit mode
   13208      * [146]15626 GCC 3.4 emits "ld: warning: relocation error:
   13209        R_SPARC_UA32"
   13210 
   13211     x86-64-specific
   13212 
   13213      * [147]14326 boehm-gc hardcodes to 3DNow! prefetch for x86_64
   13214      * [148]14723 Backported -march=nocona from mainline
   13215      * [149]15290 __float128 failed to pass to function properly
   13216 
   13217     Cygwin/Mingw32-specific
   13218 
   13219      * [150]15250 Option -mms-bitfields support on GCC 3.4 is not
   13220        conformant to MS layout
   13221      * [151]15551 -mtune=pentium4 -O2 with sjlj EH breaks stack probe
   13222        worker on windows32 targets
   13223 
   13224     Bugs specific to embedded processors
   13225 
   13226      * [152]8309 [m68k] -m5200 produces erroneous SImode set of short
   13227        varaible on stack
   13228      * [153]13250 [SH] Gcc code for rotation clobbers the register, but
   13229        gcc continues to use the register as if it was not clobbered
   13230      * [154]13803 [coldfire] movqi operand constraints too restrictivefor
   13231        TARGET_COLDFIRE
   13232      * [155]14093 [SH] ICE for code when using -mhitachi option in SH
   13233      * [156]14457 [m6811hc] ICE with simple c++ source
   13234      * [157]14542 [m6811hc] ICE on simple source
   13235      * [158]15100 [SH] cc1plus got hang-up on
   13236        libstdc++-v3/testsuite/abi_check.cc
   13237      * [159]15296 [CRIS] Delayed branch scheduling causing invalid code on
   13238        cris-*
   13239      * [160]15396 [SH] ICE with -O2 -fPIC
   13240      * [161]15782 [coldfire] m68k_output_mi_thunk emits wrong code for
   13241        ColdFire
   13242 
   13243     Testsuite problems (compiler not affected)
   13244 
   13245      * [162]11610 libstdc++ testcases 27_io/* don't work properly remotely
   13246      * [163]15488 (libstdc++) possibly insufficient file permissions for
   13247        executing test suite
   13248      * [164]15489 (libstdc++) testsuite_files determined incorrectly
   13249 
   13250     Documentation bugs
   13251 
   13252      * [165]13928 (libstdc++) no whatis info in some man pages generated
   13253        by doxygen
   13254      * [166]14150 Ada documentation out of date
   13255      * [167]14949 (c++) Need to document method visibility changes
   13256      * [168]15123 libstdc++-doc: Allocators.3 manpage is empty
   13257      __________________________________________________________________
   13258 
   13259 GCC 3.4.2
   13260 
   13261   Bug Fixes
   13262 
   13263    This section lists the problem reports (PRs) from GCC's bug tracking
   13264    system that are known to be fixed in the 3.4.2 release. This list might
   13265    not be complete (that is, it is possible that some PRs that have been
   13266    fixed are not listed here).
   13267 
   13268     Bootstrap failures and issues
   13269 
   13270      * [169]16469 [mips-sgi-irix5.3] bootstrap fails in
   13271        libstdc++-v3/testsuite
   13272      * [170]16344 [hppa-linux-gnu] libstdc++'s PCH built by
   13273        profiledbootstrap does not work with the built compiler
   13274      * [171]16842 [Solaris/x86] mkheaders can not find mkheaders.conf
   13275 
   13276     Multi-platform internal compiler errors (ICEs)
   13277 
   13278      * [172]12608 (c++) ICE: expected class 't', have 'x' (error_mark) in
   13279        cp_parser_class_specifier, in cp/parser.c
   13280      * [173]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c
   13281      * [174]15461 (c++) ICE due to NRV and inlining
   13282      * [175]15890 (c++) ICE in c_expand_expr, in c-common.c
   13283      * [176]16180 ICE: segmentation fault in RTL optimization
   13284      * [177]16224 (c++) ICE in write_unscoped_name (template/namespace)
   13285      * [178]16408 ICE: in delete_insn, in cfgrtl.c
   13286      * [179]16529 (c++) ICE for: namespace-alias shall not be declared as
   13287        the name of any other entity
   13288      * [180]16698 (c++) ICE with exceptions and declaration of __cxa_throw
   13289      * [181]16706 (c++) ICE in finish_member_declaration, in
   13290        cp/semantics.c
   13291      * [182]16810 (c++) Legal C++ program with cast gives ICE in
   13292        build_ptrmemfunc
   13293      * [183]16851 (c++) ICE when throwing a comma expression
   13294      * [184]16870 (c++) Boost.Spirit causes ICE in tsubst, in cp/pt.c
   13295      * [185]16904 (c++) ICE in finish_class_member_access_expr, in
   13296        cp/typeck.c
   13297      * [186]16905 (c++) ICE (segfault) with exceptions
   13298      * [187]16964 (c++) ICE in cp_parser_class_specifier due to
   13299        redefinition
   13300      * [188]17068 (c++) ICE: tree check: expected class 'd', have 'x'
   13301        (identifier_node) in dependent_template_p, in cp/pt.c
   13302 
   13303     Preprocessor bugs
   13304 
   13305      * [189]16366 Preprocessor option -remap causes memory corruption
   13306 
   13307     Optimization
   13308 
   13309      * [190]15345 unreferenced nested inline functions not optimized away
   13310      * [191]16590 Incorrect execution when compiling with -O2
   13311      * [192]16693 Bitwise AND is lost when used within a cast to an enum
   13312        of the same precision
   13313      * [193]17078 Jump into if(0) substatement fails
   13314 
   13315     Problems in generated debug information
   13316 
   13317      * [194]13956 incorrect stabs for nested local variables
   13318 
   13319     C front end bugs
   13320 
   13321      * [195]16684 GCC should not warn about redundant redeclarations of
   13322        built-ins
   13323 
   13324     C++ compiler and library
   13325 
   13326      * [196]12658 Thread safety problems in locale::global() and
   13327        locale::locale()
   13328      * [197]13092 g++ accepts invalid pointer-to-member conversion
   13329      * [198]15320 Excessive memory consumption
   13330      * [199]16246 Incorrect template argument deduction
   13331      * [200]16273 Memory exhausted when using nested classes and virtual
   13332        functions
   13333      * [201]16401 ostringstream in gcc 3.4.x very slow for big data
   13334      * [202]16411 undefined reference to
   13335        __gnu_cxx::stdio_sync_filebuf<char, std::char_traits<char>
   13336        >::file()
   13337      * [203]16489 G++ incorrectly rejects use of a null constant integral
   13338        expression as a null constant pointer
   13339      * [204]16618 offsetof fails with constant member
   13340      * [205]16637 syntax error reported for valid input code
   13341      * [206]16717 __attribute__((constructor)) broken in C++
   13342      * [207]16813 compiler error in DEBUG version of range insertion
   13343        std::map::insert
   13344      * [208]16853 pointer-to-member initialization from incompatible one
   13345        accepted
   13346      * [209]16889 ambiguity is not detected
   13347      * [210]16959 Segmentation fault in ios_base::sync_with_stdio
   13348 
   13349     Java compiler and library
   13350 
   13351      * [211]7587 direct threaded interpreter not thread-safe
   13352      * [212]16473 ServerSocket accept() leaks file descriptors
   13353      * [213]16478 Hash synchronization deadlock with finalizers
   13354 
   13355     Alpha-specific
   13356 
   13357      * [214]10695 ICE in dwarf2out_frame_debug_expr, in dwarf2out.c
   13358      * [215]16974 could not split insn (ice in final_scan_insn, in
   13359        final.c)
   13360 
   13361     x86-specific
   13362 
   13363      * [216]16298 ICE in output_operand
   13364      * [217]17113 ICE with SSE2 intrinsics
   13365 
   13366     x86-64 specific
   13367 
   13368      * [218]14697 libstdc++ couldn't find 32bit libgcc_s
   13369 
   13370     MIPS-specific
   13371 
   13372      * [219]15869 [mips64] No NOP after LW (with -mips1 -O0)
   13373      * [220]16325 [mips64] value profiling clobbers gp on mips
   13374      * [221]16357 [mipsisa64-elf] ICE copying 7 bytes between extern
   13375        char[]s
   13376      * [222]16380 [mips64] Use of uninitialised register after dbra
   13377        conversion
   13378      * [223]16407 [mips64] Unaligned access to local variables
   13379      * [224]16643 [mips64] verify_local_live_at_start ICE after
   13380        crossjumping & cfgcleanup
   13381 
   13382     ARM-specific
   13383 
   13384      * [225]15927 THUMB -O2: strength-reduced iteration variable ends up
   13385        off by 1
   13386      * [226]15948 THUMB: ICE with non-commutative cbranch
   13387      * [227]17019 THUMB: bad switch statement in md code for
   13388        addsi3_cbranch_scratch
   13389 
   13390     IA64-specific
   13391 
   13392      * [228]16130 ICE on valid code: in bundling, in config/ia64/ia64.c
   13393        (-mtune=merced)
   13394      * [229]16142 ICE on valid code: in bundling, in config/ia64/ia64.c
   13395        (-mtune=itanium)
   13396      * [230]16278 Gcc failed to build Linux kernel with -mtune=merced
   13397      * [231]16414 ICE on valid code: typo in comparison of asm_noperands
   13398        result
   13399      * [232]16445 ICE on valid code: don't count ignored insns
   13400      * [233]16490 ICE (segfault) while compiling with -fprofile-use
   13401      * [234]16683 ia64 does not honor SUBTARGET_EXTRA_SPECS
   13402 
   13403     PowerPC-specific
   13404 
   13405      * [235]16195 (ppc64): Miscompilation of GCC 3.3.x by 3.4.x
   13406      * [236]16239 ICE on ppc64 (mozilla 1.7 compile, -O1 -fno-exceptions
   13407        issue)
   13408 
   13409     SPARC-specific
   13410 
   13411      * [237]16199 ICE while compiling apache 2.0.49
   13412      * [238]16416 -m64 doesn't imply -mcpu=v9 anymore
   13413      * [239]16430 ICE when returning non-C aggregates larger than 16 bytes
   13414 
   13415     Bugs specific to embedded processors
   13416 
   13417      * [240]16379 [m32r] can't output large model function call of memcpy
   13418      * [241]17093 [m32r] ICE with -msdata=use -O0
   13419      * [242]17119 [m32r] ICE at switch case 0x8000
   13420 
   13421     DJGPP-specific
   13422 
   13423      * [243]15928 libstdc++ in 3.4.x doesn't cross-compile for djgpp
   13424 
   13425     Alpha Tru64-specific
   13426 
   13427      * [244]16210 libstdc++ gratuitously omits "long long" I/O
   13428 
   13429     Testsuite, documentation issues (compiler is not affected):
   13430 
   13431      * [245]15488 (libstdc++) possibly insufficient file permissions for
   13432        executing test suite
   13433      * [246]16250 ada/doctools runs makeinfo even in release tarball
   13434      __________________________________________________________________
   13435 
   13436 GCC 3.4.3
   13437 
   13438    This is the [247]list of problem reports (PRs) from GCC's bug tracking
   13439    system that are known to be fixed in the 3.4.3 release. This list might
   13440    not be complete (that is, it is possible that some PRs that have been
   13441    fixed are not listed here).
   13442 
   13443     Bootstrap failures
   13444 
   13445      * [248]17369 [ia64] Bootstrap failure with binutils-2.15.90.0.1.1
   13446      * [249]17850 [arm-elf] bootstrap failure - libstdc++ uses strtold
   13447        when undeclared
   13448 
   13449     Internal compiler errors (ICEs) affecting multiple platforms
   13450 
   13451      * [250]13948 (java) GCJ segmentation fault while compiling GL4Java
   13452        .class files
   13453      * [251]14492 ICE in loc_descriptor_from_tree, in dwarf2out.c
   13454      * [252]16301 (c++) ICE when "strong" attribute is attached to a using
   13455        directive
   13456      * [253]16566 ICE with flexible arrays
   13457      * [254]17023 ICE with nested functions in parameter declaration
   13458      * [255]17027 ICE with noreturn function in loop at -O2
   13459      * [256]17524 ICE in grokdeclarator, in cp/decl.c
   13460      * [257]17826 (c++) ICE in cp_tree_equal
   13461 
   13462     C and optimization bugs
   13463 
   13464      * [258]15526 -ftrapv aborts on 0 * (-1)
   13465      * [259]16999 #ident stopped working
   13466      * [260]17503 quadratic behaviour in invalid_mode_change_p
   13467      * [261]17581 Long long arithmetic fails inside a switch/case
   13468        statement when compiled with -O2
   13469      * [262]18129 -fwritable-strings doesn't work
   13470 
   13471     C++ compiler and library bugs
   13472 
   13473      * [263]10975 incorrect initial ostringstream::tellp()
   13474      * [264]11722 Unbuffered filebuf::sgetn is slow
   13475      * [265]14534 Unrecognizing static function as a template parameter
   13476        when its return value is also templated
   13477      * [266]15172 Copy constructor optimization in aggregate
   13478        initialization
   13479      * [267]15786 Bad error message for frequently occuring error.
   13480      * [268]16162 Rejects valid member-template-definition
   13481      * [269]16612 empty basic_strings can't live in shared memory
   13482      * [270]16715 std::basic_iostream is instantiated when used, even
   13483        though instantiations are already contained in libstdc++
   13484      * [271]16848 code in /ext/demangle.h appears broken
   13485      * [272]17132 GCC fails to eliminate function template specialization
   13486        when argument deduction fails
   13487      * [273]17259 One more _S_leaf incorrectly qualified with _RopeRep::
   13488        in ropeimpl.h
   13489      * [274]17327 use of `enumeral_type' in template type unification
   13490      * [275]17393 "unused variable '._0'" warning with -Wall
   13491      * [276]17501 Confusion with member templates
   13492      * [277]17537 g++ not passing -lstdc++ to linker when all command line
   13493        arguments are libraries
   13494      * [278]17585 usage of unqualified name of static member from within
   13495        class not allowed
   13496      * [279]17821 Poor diagnostic for using "." instead of "->"
   13497      * [280]17829 wrong error: call of overloaded function is ambiguous
   13498      * [281]17851 Misleading diagnostic for invalid function declarations
   13499        with undeclared types
   13500      * [282]17976 Destructor is called twice
   13501      * [283]18020 rejects valid definition of enum value in template
   13502      * [284]18093 bogus conflict in namespace aliasing
   13503      * [285]18140 C++ parser bug when using >> in templates
   13504 
   13505     Fortran
   13506 
   13507      * [286]17541 data statements with double precision constants fail
   13508 
   13509     x86-specific
   13510 
   13511      * [287]17853 -O2 ICE for MMX testcase
   13512 
   13513     SPARC-specific
   13514 
   13515      * [288]17245 ICE compiling gsl-1.5 statistics/lag1.c
   13516 
   13517     Darwin-specific
   13518 
   13519      * [289]17167 FATAL:Symbol L_foo$stub already defined.
   13520 
   13521     AIX-specific
   13522 
   13523      * [290]17277 could not catch an exception when specified -maix64
   13524 
   13525     Solaris-specific
   13526 
   13527      * [291]17505 <cmath> calls acosf(), ceilf(), and other functions
   13528        missing from system libraries
   13529 
   13530     HP/UX specific:
   13531 
   13532      * [292]17684 /usr/ccs/bin/ld: Can't create libgcc_s.sl
   13533 
   13534     ARM-specific
   13535 
   13536      * [293]17384 ICE with mode attribute on structures
   13537 
   13538     MIPS-specific
   13539 
   13540      * [294]17770 No NOP after LWL with -mips1
   13541 
   13542     Other embedded target specific
   13543 
   13544      * [295]11476 [arc-elf] gcc ICE on newlib's vfprintf.c
   13545      * [296]14064 [avr-elf] -fdata-sections triggers ICE
   13546      * [297]14678 [m68hc11-elf] gcc ICE
   13547      * [298]15583 [powerpc-rtems] powerpc-rtems lacks __USE_INIT_FINI__
   13548      * [299]15790 [i686-coff] Alignment error building gcc with i686-coff
   13549        target
   13550      * [300]15886 [SH] Miscompilation with -O2 -fPIC
   13551      * [301]16884 [avr-elf] [fweb related] bug while initializing
   13552        variables
   13553 
   13554     Bugs relating to debugger support
   13555 
   13556      * [302]13841 missing debug info for _Complex function arguments
   13557      * [303]15860 [big-endian targets] No DW_AT_location debug info is
   13558        emitted for formal arguments to a function that uses "register"
   13559        qualifiers
   13560 
   13561     Testsuite issues (compiler not affected)
   13562 
   13563      * [304]17465 Testsuite in libffi overrides LD_LIBRARY_PATH
   13564      * [305]17469 Testsuite in libstdc++ overrides LD_LIBRARY_PATH
   13565      * [306]18138 [mips-sgi-irix6.5] libgcc_s.so.1 not found by 64-bit
   13566        testsuite
   13567 
   13568     Documentation
   13569 
   13570      * [307]15498 typo in gcc manual: non-existing locale example en_UK,
   13571        should be en_GB
   13572      * [308]15747 [mips-sgi-irix5.3] /bin/sh hangs during bootstrap:
   13573        document broken shell
   13574      * [309]16406 USE_LD_AS_NEEDED undocumented
   13575      __________________________________________________________________
   13576 
   13577 GCC 3.4.4
   13578 
   13579    This is the [310]list of problem reports (PRs) from GCC's bug tracking
   13580    system that are known to be fixed in the 3.4.4 release. This list might
   13581    not be complete (that is, it is possible that some PRs that have been
   13582    fixed are not listed here).
   13583      __________________________________________________________________
   13584 
   13585 GCC 3.4.5
   13586 
   13587    This is the [311]list of problem reports (PRs) from GCC's bug tracking
   13588    system that are known to be fixed in the 3.4.5 release. This list might
   13589    not be complete (that is, it is possible that some PRs that have been
   13590    fixed are not listed here).
   13591 
   13592     Bootstrap issues
   13593 
   13594      * [312]24688 sco_math fixincl breaks math.h
   13595 
   13596     C compiler bugs
   13597 
   13598      * [313]17188 struct Foo { } redefinition
   13599      * [314]20187 wrong code for ((unsigned char)(unsigned long
   13600        long)((a?a:1)&(a*b)))?0:1)
   13601      * [315]21873 infinite warning loop on bad array initializer
   13602      * [316]21899 enum definition accepts values to be overriden
   13603      * [317]22061 ICE in find_function_data, in function.c
   13604      * [318]22308 Failure to diagnose violation of constraint 6.516p2
   13605      * [319]22458 ICE on missing brace
   13606      * [320]22589 ICE casting to long long
   13607      * [321]24101 Segfault with preprocessed source
   13608 
   13609     C++ compiler and library bugs
   13610 
   13611      * [322]10611 operations on vector mode not recognized in C++
   13612      * [323]13377 unexpected behavior of namespace usage directive
   13613      * [324]16002 Strange error message with new parser
   13614      * [325]17413 local classes as template argument
   13615      * [326]17609 spurious error message after using keyword
   13616      * [327]17618 ICE in cp_convert_to_pointer, in cp/cvt.c
   13617      * [328]18124 ICE with invalid template template parameter
   13618      * [329]18155 typedef in template declaration not rejected
   13619      * [330]18177 ICE with const_cast for undeclared variable
   13620      * [331]18368 C++ error message regression
   13621      * [332]16378 ICE when returning a copy of a packed member
   13622      * [333]18466 int ::i; accepted
   13623      * [334]18512 ICE on invalid usage of template base class
   13624      * [335]18454 ICE when returning undefined type
   13625      * [336]18738 typename not allowed with non-dependent qualified name
   13626      * [337]18803 rejects access to operator() in template
   13627      * [338]19004 ICE in uses_template_parms, in cp/pt.c
   13628      * [339]19208 Spurious error about variably modified type
   13629      * [340]18253 bad error message / ICE for invalid template parameter
   13630      * [341]19608 ICE after friend function definition in local class
   13631      * [342]19884 ICE on explicit instantiation of a non-template
   13632        constructor
   13633      * [343]20153 ICE when C++ template function contains anonymous union
   13634      * [344]20563 Infinite loop in diagnostic (and ice after error
   13635        message)
   13636      * [345]20789 ICE with incomplete type in template
   13637      * [346]21336 Internal compiler error when using custom new operators
   13638      * [347]21768 ICE in error message due to violation of coding
   13639        conventions
   13640      * [348]21853 constness of pointer to data member ignored
   13641      * [349]21903 Default argument of template function causes a
   13642        compile-time error
   13643      * [350]21983 multiple diagnostics
   13644      * [351]21987 New testsuite failure
   13645        g++.dg/warn/conversion-function-1.C
   13646      * [352]22153 ICE on invalid template specialization
   13647      * [353]22172 Internal compiler error, seg fault.
   13648      * [354]21286 filebuf::xsgetn vs pipes
   13649      * [355]22233 ICE with wrong number of template parameters
   13650      * [356]22508 ICE after invalid operator new
   13651      * [357]22545 ICE with pointer to class member & user defined
   13652        conversion operator
   13653      * [358]23528 Wrong default allocator in ext/hash_map
   13654      * [359]23550 char_traits requirements/1.cc test bad math
   13655      * [360]23586 Bad diagnostic for invalid namespace-name
   13656      * [361]23624 ICE in invert_truthvalue, in fold-const.c
   13657      * [362]23639 Bad error message: not a member of '<declaration error>'
   13658      * [363]23797 ICE on typename outside template
   13659      * [364]23965 Bogus error message: no matching function for call to
   13660        'foo(<type error>)'
   13661      * [365]24052 &#`label_decl' not supported by dump_expr#<expression
   13662        error>
   13663      * [366]24580 virtual base class cause exception not to be caught
   13664 
   13665     Problems in generated debug information
   13666 
   13667      * [367]24267 Bad DWARF for altivec vectors
   13668 
   13669     Optimizations issues
   13670 
   13671      * [368]17810 ICE in verify_local_live_at_start
   13672      * [369]17860 Wrong generated code for loop with varying bound
   13673      * [370]21709 ICE on compile-time complex NaN
   13674      * [371]21964 broken tail call at -O2 or more
   13675      * [372]22167 Strange optimization bug when using -Os
   13676      * [373]22619 Compilation failure for real_const_1.f and
   13677        real_const_2.f90
   13678      * [374]23241 Invalid code generated for comparison of uchar to 255
   13679      * [375]23478 Miscompilation due to reloading of a var that is also
   13680        used in EH pad
   13681      * [376]24470 segmentation fault in cc1plus when compiling with -O
   13682      * [377]24950 ICE in operand_subword_force
   13683 
   13684     Precompiled headers problems
   13685 
   13686      * [378]14400 Cannot compile qt-x11-free-3.3.0
   13687      * [379]14940 PCH largefile test fails on various platforms
   13688 
   13689     Preprocessor bugs
   13690 
   13691      * [380]20239 ICE on empty preprocessed input
   13692      * [381]15220 "gcc -E -MM -MG" reports missing system headers in
   13693        source directory
   13694 
   13695     Testsuite issues
   13696 
   13697      * [382]19275 gcc.dg/20020919-1.c fails with -fpic/-fPIC on
   13698        i686-pc-linux-gnu
   13699 
   13700     Alpha specific
   13701 
   13702      * [383]21888 bootstrap failure with linker relaxation enabled
   13703 
   13704     ARM specific
   13705 
   13706      * [384]15342 [arm-linux]: ICE in verify_local_live_at_start
   13707      * [385]23985 Memory aliasing information incorrect in inlined memcpy
   13708 
   13709     ColdFile specific
   13710 
   13711      * [386]16719 Illegal move of byte into address register causes
   13712        compiler to ICE
   13713 
   13714     HPPA specific
   13715 
   13716      * [387]21723 ICE while building libgfortran
   13717      * [388]21841 -mhp-ld/-mgnu-ld documentation
   13718 
   13719     IA-64 specific
   13720 
   13721      * [389]23644 IA-64 hardware models and configuration options
   13722        documentation error
   13723      * [390]24718 Shared libgcc not used for linking by default
   13724 
   13725     M68000 specific
   13726 
   13727      * [391]18421 ICE in reload_cse_simplify_operands, in postreload.c
   13728 
   13729     MIPS specific
   13730 
   13731      * [392]20621 ICE in change_address_1, in emit-rtl.c
   13732 
   13733     PowerPC and PowerPC64 specific
   13734 
   13735      * [393]18583 error on valid code: const
   13736        __attribute__((altivec(vector__))) doesn't work in arrays
   13737      * [394]20191 ICE in reload_cse_simplify_operands
   13738      * [395]22083 AIX: TARGET_C99_FUNCTIONS is wrongly defined
   13739      * [396]23070 CALL_V4_CLEAR_FP_ARGS flag not properly set
   13740      * [397]23404 gij trashes args of functions with more than 8 fp args
   13741      * [398]23539 C & C++ compiler generating misaligned references
   13742        regardless of compiler flags
   13743      * [399]24102 floatdisf2_internal2 broken
   13744      * [400]24465 -mminimal-toc miscompilation of __thread vars
   13745 
   13746     Solaris specific
   13747 
   13748      * [401]19933 Problem with define of HUGE_VAL in math_c99
   13749      * [402]21889 Native Solaris assembler cannot grok DTP-relative debug
   13750        symbols
   13751 
   13752     SPARC specific
   13753 
   13754      * [403]19300 PCH failures on sparc-linux
   13755      * [404]20301 Assembler labels have a leading "-"
   13756      * [405]20673 C PCH testsuite assembly comparison failure
   13757 
   13758     x86 and x86_64 specific
   13759 
   13760      * [406]18582 ICE with arrays of type V2DF
   13761      * [407]19340 Compilation SEGFAULTs with -O1 -fschedule-insns2
   13762        -fsched2-use-traces
   13763      * [408]21716 ICE in reg-stack.c's swap_rtx_condition
   13764      * [409]24315 amd64 fails -fpeephole2
   13765      __________________________________________________________________
   13766 
   13767 GCC 3.4.6
   13768 
   13769    This is the [410]list of problem reports (PRs) from GCC's bug tracking
   13770    system that are known to be fixed in the 3.4.6 release. This list might
   13771    not be complete (that is, it is possible that some PRs that have been
   13772    fixed are not listed here).
   13773 
   13774 
   13775     For questions related to the use of GCC, please consult these web
   13776     pages and the [411]GCC manuals. If that fails, the
   13777     [412]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   13778     web pages and the development of GCC are welcome on our developer
   13779     list at [413]gcc (a] gcc.gnu.org. All of [414]our lists have public
   13780     archives.
   13781 
   13782    Copyright (C) [415]Free Software Foundation, Inc. Verbatim copying and
   13783    distribution of this entire article is permitted in any medium,
   13784    provided this notice is preserved.
   13785 
   13786    These pages are [416]maintained by the GCC team. Last modified
   13787    2019-11-28[417].
   13788 
   13789 References
   13790 
   13791    1. http://gcc.gnu.org/gcc-3.4/changes.html#3.4.6
   13792    2. http://gcc.gnu.org/gcc-3.4/changes.html#cplusplus
   13793    3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems
   13794    4. http://gcc.gnu.org/gcc-3.4/changes.html#obsolete_systems
   13795    5. http://gcc.gnu.org/gcc-3.4/mips-abi.html
   13796    6. http://gcc.gnu.org/gcc-3.4/sparc-abi.html
   13797    7. https://www.boost.org/
   13798    8. https://gcc.gnu.org/PR11953
   13799    9. https://gcc.gnu.org/PR8361
   13800   10. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Other-Builtins.html#Other Builtins
   13801   11. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_closed.html#209
   13802   12. http://gcc.gnu.org/bugs/#cxx_rvalbind
   13803   13. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html
   13804   14. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html
   13805   15. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Objective-C-Dialect-Options.html
   13806   16. http://www.gnu.org/software/classpath/
   13807   17. http://www.eclipse.org/
   13808   18. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/g77/News.html
   13809   19. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Alpha-Built-in-Functions.html
   13810   20. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Processor-pipeline-description.html
   13811   21. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Comparison-of-the-two-descriptions.html
   13812   22. https://gcc.gnu.org/onlinedocs/gcc-3.4.3/gccint/Processor-pipeline-description.html
   13813   23. http://gcc.gnu.org/gcc-3.4/mips-abi.html
   13814   24. http://gcc.gnu.org/gcc-3.4/powerpc-abi.html
   13815   25. http://gcc.gnu.org/gcc-3.4/sparc-abi.html
   13816   26. https://gcc.gnu.org/bugzilla/buglist.cgi?short_desc_type=notregexp&short_desc=\[3\.4.*[Rr]egression&target_milestone=3.4.0&bug_status=RESOLVED&resolution=FIXED
   13817   27. https://gcc.gnu.org/PR10129
   13818   28. https://gcc.gnu.org/PR14576
   13819   29. https://gcc.gnu.org/PR14760
   13820   30. https://gcc.gnu.org/PR14671
   13821   31. https://gcc.gnu.org/PR15093
   13822   32. https://gcc.gnu.org/PR15178
   13823   33. https://gcc.gnu.org/PR12753
   13824   34. https://gcc.gnu.org/PR13985
   13825   35. https://gcc.gnu.org/PR14810
   13826   36. https://gcc.gnu.org/PR14883
   13827   37. https://gcc.gnu.org/PR15044
   13828   38. https://gcc.gnu.org/PR15057
   13829   39. https://gcc.gnu.org/PR15064
   13830   40. https://gcc.gnu.org/PR15142
   13831   41. https://gcc.gnu.org/PR15159
   13832   42. https://gcc.gnu.org/PR15165
   13833   43. https://gcc.gnu.org/PR15193
   13834   44. https://gcc.gnu.org/PR15209
   13835   45. https://gcc.gnu.org/PR15227
   13836   46. https://gcc.gnu.org/PR15285
   13837   47. https://gcc.gnu.org/PR15299
   13838   48. https://gcc.gnu.org/PR15329
   13839   49. https://gcc.gnu.org/PR15550
   13840   50. https://gcc.gnu.org/PR15554
   13841   51. https://gcc.gnu.org/PR15640
   13842   52. https://gcc.gnu.org/PR15666
   13843   53. https://gcc.gnu.org/PR15696
   13844   54. https://gcc.gnu.org/PR15701
   13845   55. https://gcc.gnu.org/PR15761
   13846   56. https://gcc.gnu.org/PR15829
   13847   57. https://gcc.gnu.org/PR14538
   13848   58. https://gcc.gnu.org/PR12391
   13849   59. https://gcc.gnu.org/PR14649
   13850   60. https://gcc.gnu.org/PR15004
   13851   61. https://gcc.gnu.org/PR15749
   13852   62. https://gcc.gnu.org/PR10646
   13853   63. https://gcc.gnu.org/PR12077
   13854   64. https://gcc.gnu.org/PR13598
   13855   65. https://gcc.gnu.org/PR14211
   13856   66. https://gcc.gnu.org/PR14220
   13857   67. https://gcc.gnu.org/PR14245
   13858   68. https://gcc.gnu.org/PR14340
   13859   69. https://gcc.gnu.org/PR14600
   13860   70. https://gcc.gnu.org/PR14668
   13861   71. https://gcc.gnu.org/PR14775
   13862   72. https://gcc.gnu.org/PR14821
   13863   73. https://gcc.gnu.org/PR14930
   13864   74. https://gcc.gnu.org/PR14932
   13865   75. https://gcc.gnu.org/PR14950
   13866   76. https://gcc.gnu.org/PR14962
   13867   77. https://gcc.gnu.org/PR14975
   13868   78. https://gcc.gnu.org/PR15002
   13869   79. https://gcc.gnu.org/PR15025
   13870   80. https://gcc.gnu.org/PR15046
   13871   81. https://gcc.gnu.org/PR15069
   13872   82. https://gcc.gnu.org/PR15074
   13873   83. https://gcc.gnu.org/PR15083
   13874   84. https://gcc.gnu.org/PR15096
   13875   85. https://gcc.gnu.org/PR15287
   13876   86. https://gcc.gnu.org/PR15317
   13877   87. https://gcc.gnu.org/PR15337
   13878   88. https://gcc.gnu.org/PR15361
   13879   89. https://gcc.gnu.org/PR15412
   13880   90. https://gcc.gnu.org/PR15427
   13881   91. https://gcc.gnu.org/PR15471
   13882   92. https://gcc.gnu.org/PR15503
   13883   93. https://gcc.gnu.org/PR15507
   13884   94. https://gcc.gnu.org/PR15542
   13885   95. https://gcc.gnu.org/PR15565
   13886   96. https://gcc.gnu.org/PR15625
   13887   97. https://gcc.gnu.org/PR15629
   13888   98. https://gcc.gnu.org/PR15742
   13889   99. https://gcc.gnu.org/PR15775
   13890  100. https://gcc.gnu.org/PR15821
   13891  101. https://gcc.gnu.org/PR15862
   13892  102. https://gcc.gnu.org/PR15875
   13893  103. https://gcc.gnu.org/PR15877
   13894  104. https://gcc.gnu.org/PR15947
   13895  105. https://gcc.gnu.org/PR16020
   13896  106. https://gcc.gnu.org/PR16154
   13897  107. https://gcc.gnu.org/PR16174
   13898  108. https://gcc.gnu.org/PR14315
   13899  109. https://gcc.gnu.org/PR15151
   13900  110. https://gcc.gnu.org/PR7993
   13901  111. https://gcc.gnu.org/PR15228
   13902  112. https://gcc.gnu.org/PR15345
   13903  113. https://gcc.gnu.org/PR15945
   13904  114. https://gcc.gnu.org/PR15526
   13905  115. https://gcc.gnu.org/PR14690
   13906  116. https://gcc.gnu.org/PR15112
   13907  117. https://gcc.gnu.org/PR15067
   13908  118. https://gcc.gnu.org/PR1963
   13909  119. https://gcc.gnu.org/PR15717
   13910  120. https://gcc.gnu.org/PR14782
   13911  121. https://gcc.gnu.org/PR14828
   13912  122. https://gcc.gnu.org/PR15202
   13913  123. https://gcc.gnu.org/PR14610
   13914  124. https://gcc.gnu.org/PR14813
   13915  125. https://gcc.gnu.org/PR14857
   13916  126. https://gcc.gnu.org/PR15598
   13917  127. https://gcc.gnu.org/PR15653
   13918  128. https://gcc.gnu.org/PR15189
   13919  129. https://gcc.gnu.org/PR15331
   13920  130. https://gcc.gnu.org/PR16144
   13921  131. https://gcc.gnu.org/PR16176
   13922  132. https://gcc.gnu.org/PR11591
   13923  133. https://gcc.gnu.org/PR12028
   13924  134. https://gcc.gnu.org/PR14478
   13925  135. https://gcc.gnu.org/PR14567
   13926  136. https://gcc.gnu.org/PR14715
   13927  137. https://gcc.gnu.org/PR14902
   13928  138. https://gcc.gnu.org/PR14924
   13929  139. https://gcc.gnu.org/PR14960
   13930  140. https://gcc.gnu.org/PR15106
   13931  141. https://gcc.gnu.org/PR16026
   13932  142. https://gcc.gnu.org/PR15191
   13933  143. https://gcc.gnu.org/PR15662
   13934  144. https://gcc.gnu.org/PR15054
   13935  145. https://gcc.gnu.org/PR15783
   13936  146. https://gcc.gnu.org/PR15626
   13937  147. https://gcc.gnu.org/PR14326
   13938  148. https://gcc.gnu.org/PR14723
   13939  149. https://gcc.gnu.org/PR15290
   13940  150. https://gcc.gnu.org/PR15250
   13941  151. https://gcc.gnu.org/PR15551
   13942  152. https://gcc.gnu.org/PR8309
   13943  153. https://gcc.gnu.org/PR13250
   13944  154. https://gcc.gnu.org/PR13803
   13945  155. https://gcc.gnu.org/PR14093
   13946  156. https://gcc.gnu.org/PR14457
   13947  157. https://gcc.gnu.org/PR14542
   13948  158. https://gcc.gnu.org/PR15100
   13949  159. https://gcc.gnu.org/PR15296
   13950  160. https://gcc.gnu.org/PR15396
   13951  161. https://gcc.gnu.org/PR15782
   13952  162. https://gcc.gnu.org/PR11610
   13953  163. https://gcc.gnu.org/PR15488
   13954  164. https://gcc.gnu.org/PR15489
   13955  165. https://gcc.gnu.org/PR13928
   13956  166. https://gcc.gnu.org/PR14150
   13957  167. https://gcc.gnu.org/PR14949
   13958  168. https://gcc.gnu.org/PR15123
   13959  169. https://gcc.gnu.org/PR16469
   13960  170. https://gcc.gnu.org/PR16344
   13961  171. https://gcc.gnu.org/PR16842
   13962  172. https://gcc.gnu.org/PR12608
   13963  173. https://gcc.gnu.org/PR14492
   13964  174. https://gcc.gnu.org/PR15461
   13965  175. https://gcc.gnu.org/PR15890
   13966  176. https://gcc.gnu.org/PR16180
   13967  177. https://gcc.gnu.org/PR16224
   13968  178. https://gcc.gnu.org/PR16408
   13969  179. https://gcc.gnu.org/PR16529
   13970  180. https://gcc.gnu.org/PR16698
   13971  181. https://gcc.gnu.org/PR16706
   13972  182. https://gcc.gnu.org/PR16810
   13973  183. https://gcc.gnu.org/PR16851
   13974  184. https://gcc.gnu.org/PR16870
   13975  185. https://gcc.gnu.org/PR16904
   13976  186. https://gcc.gnu.org/PR16905
   13977  187. https://gcc.gnu.org/PR16964
   13978  188. https://gcc.gnu.org/PR17068
   13979  189. https://gcc.gnu.org/PR16366
   13980  190. https://gcc.gnu.org/PR15345
   13981  191. https://gcc.gnu.org/PR16590
   13982  192. https://gcc.gnu.org/PR16693
   13983  193. https://gcc.gnu.org/PR17078
   13984  194. https://gcc.gnu.org/PR13956
   13985  195. https://gcc.gnu.org/PR16684
   13986  196. https://gcc.gnu.org/PR12658
   13987  197. https://gcc.gnu.org/PR13092
   13988  198. https://gcc.gnu.org/PR15320
   13989  199. https://gcc.gnu.org/PR16246
   13990  200. https://gcc.gnu.org/PR16273
   13991  201. https://gcc.gnu.org/PR16401
   13992  202. https://gcc.gnu.org/PR16411
   13993  203. https://gcc.gnu.org/PR16489
   13994  204. https://gcc.gnu.org/PR16618
   13995  205. https://gcc.gnu.org/PR16637
   13996  206. https://gcc.gnu.org/PR16717
   13997  207. https://gcc.gnu.org/PR16813
   13998  208. https://gcc.gnu.org/PR16853
   13999  209. https://gcc.gnu.org/PR16889
   14000  210. https://gcc.gnu.org/PR16959
   14001  211. https://gcc.gnu.org/PR7587
   14002  212. https://gcc.gnu.org/PR16473
   14003  213. https://gcc.gnu.org/PR16478
   14004  214. https://gcc.gnu.org/PR10695
   14005  215. https://gcc.gnu.org/PR16974
   14006  216. https://gcc.gnu.org/PR16298
   14007  217. https://gcc.gnu.org/PR17113
   14008  218. https://gcc.gnu.org/PR14697
   14009  219. https://gcc.gnu.org/PR15869
   14010  220. https://gcc.gnu.org/PR16325
   14011  221. https://gcc.gnu.org/PR16357
   14012  222. https://gcc.gnu.org/PR16380
   14013  223. https://gcc.gnu.org/PR16407
   14014  224. https://gcc.gnu.org/PR16643
   14015  225. https://gcc.gnu.org/PR15927
   14016  226. https://gcc.gnu.org/PR15948
   14017  227. https://gcc.gnu.org/PR17019
   14018  228. https://gcc.gnu.org/PR16130
   14019  229. https://gcc.gnu.org/PR16142
   14020  230. https://gcc.gnu.org/PR16278
   14021  231. https://gcc.gnu.org/PR16414
   14022  232. https://gcc.gnu.org/PR16445
   14023  233. https://gcc.gnu.org/PR16490
   14024  234. https://gcc.gnu.org/PR16683
   14025  235. https://gcc.gnu.org/PR16195
   14026  236. https://gcc.gnu.org/PR16239
   14027  237. https://gcc.gnu.org/PR16199
   14028  238. https://gcc.gnu.org/PR16416
   14029  239. https://gcc.gnu.org/PR16430
   14030  240. https://gcc.gnu.org/PR16379
   14031  241. https://gcc.gnu.org/PR17093
   14032  242. https://gcc.gnu.org/PR17119
   14033  243. https://gcc.gnu.org/PR15928
   14034  244. https://gcc.gnu.org/PR16210
   14035  245. https://gcc.gnu.org/PR15488
   14036  246. https://gcc.gnu.org/PR16250
   14037  247. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.3
   14038  248. https://gcc.gnu.org/PR17369
   14039  249. https://gcc.gnu.org/PR17850
   14040  250. https://gcc.gnu.org/PR13948
   14041  251. https://gcc.gnu.org/PR14492
   14042  252. https://gcc.gnu.org/PR16301
   14043  253. https://gcc.gnu.org/PR16566
   14044  254. https://gcc.gnu.org/PR17023
   14045  255. https://gcc.gnu.org/PR17027
   14046  256. https://gcc.gnu.org/PR17524
   14047  257. https://gcc.gnu.org/PR17826
   14048  258. https://gcc.gnu.org/PR15526
   14049  259. https://gcc.gnu.org/PR16999
   14050  260. https://gcc.gnu.org/PR17503
   14051  261. https://gcc.gnu.org/PR17581
   14052  262. https://gcc.gnu.org/PR18129
   14053  263. https://gcc.gnu.org/PR10975
   14054  264. https://gcc.gnu.org/PR11722
   14055  265. https://gcc.gnu.org/PR14534
   14056  266. https://gcc.gnu.org/PR15172
   14057  267. https://gcc.gnu.org/PR15786
   14058  268. https://gcc.gnu.org/PR16162
   14059  269. https://gcc.gnu.org/PR16612
   14060  270. https://gcc.gnu.org/PR16715
   14061  271. https://gcc.gnu.org/PR16848
   14062  272. https://gcc.gnu.org/PR17132
   14063  273. https://gcc.gnu.org/PR17259
   14064  274. https://gcc.gnu.org/PR17327
   14065  275. https://gcc.gnu.org/PR17393
   14066  276. https://gcc.gnu.org/PR17501
   14067  277. https://gcc.gnu.org/PR17537
   14068  278. https://gcc.gnu.org/PR17585
   14069  279. https://gcc.gnu.org/PR17821
   14070  280. https://gcc.gnu.org/PR17829
   14071  281. https://gcc.gnu.org/PR17851
   14072  282. https://gcc.gnu.org/PR17976
   14073  283. https://gcc.gnu.org/PR18020
   14074  284. https://gcc.gnu.org/PR18093
   14075  285. https://gcc.gnu.org/PR18140
   14076  286. https://gcc.gnu.org/PR17541
   14077  287. https://gcc.gnu.org/PR17853
   14078  288. https://gcc.gnu.org/PR17245
   14079  289. https://gcc.gnu.org/PR17167
   14080  290. https://gcc.gnu.org/PR17277
   14081  291. https://gcc.gnu.org/PR17505
   14082  292. https://gcc.gnu.org/PR17684
   14083  293. https://gcc.gnu.org/PR17384
   14084  294. https://gcc.gnu.org/PR17770
   14085  295. https://gcc.gnu.org/PR11476
   14086  296. https://gcc.gnu.org/PR14064
   14087  297. https://gcc.gnu.org/PR14678
   14088  298. https://gcc.gnu.org/PR15583
   14089  299. https://gcc.gnu.org/PR15790
   14090  300. https://gcc.gnu.org/PR15886
   14091  301. https://gcc.gnu.org/PR16884
   14092  302. https://gcc.gnu.org/PR13841
   14093  303. https://gcc.gnu.org/PR15860
   14094  304. https://gcc.gnu.org/PR17465
   14095  305. https://gcc.gnu.org/PR17469
   14096  306. https://gcc.gnu.org/PR18138
   14097  307. https://gcc.gnu.org/PR15498
   14098  308. https://gcc.gnu.org/PR15747
   14099  309. https://gcc.gnu.org/PR16406
   14100  310. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.4
   14101  311. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.5
   14102  312. https://gcc.gnu.org/PR24688
   14103  313. https://gcc.gnu.org/PR17188
   14104  314. https://gcc.gnu.org/PR20187
   14105  315. https://gcc.gnu.org/PR21873
   14106  316. https://gcc.gnu.org/PR21899
   14107  317. https://gcc.gnu.org/PR22061
   14108  318. https://gcc.gnu.org/PR22208
   14109  319. https://gcc.gnu.org/PR22458
   14110  320. https://gcc.gnu.org/PR22589
   14111  321. https://gcc.gnu.org/PR24101
   14112  322. https://gcc.gnu.org/PR10611
   14113  323. https://gcc.gnu.org/PR13377
   14114  324. https://gcc.gnu.org/PR16002
   14115  325. https://gcc.gnu.org/PR17413
   14116  326. https://gcc.gnu.org/PR17609
   14117  327. https://gcc.gnu.org/PR17618
   14118  328. https://gcc.gnu.org/PR18124
   14119  329. https://gcc.gnu.org/PR18155
   14120  330. https://gcc.gnu.org/PR18177
   14121  331. https://gcc.gnu.org/PR18368
   14122  332. https://gcc.gnu.org/PR18378
   14123  333. https://gcc.gnu.org/PR18466
   14124  334. https://gcc.gnu.org/PR18512
   14125  335. https://gcc.gnu.org/PR18545
   14126  336. https://gcc.gnu.org/PR18738
   14127  337. https://gcc.gnu.org/PR18803
   14128  338. https://gcc.gnu.org/PR19004
   14129  339. https://gcc.gnu.org/PR19208
   14130  340. https://gcc.gnu.org/PR19253
   14131  341. https://gcc.gnu.org/PR19608
   14132  342. https://gcc.gnu.org/PR19884
   14133  343. https://gcc.gnu.org/PR20153
   14134  344. https://gcc.gnu.org/PR20563
   14135  345. https://gcc.gnu.org/PR20789
   14136  346. https://gcc.gnu.org/PR21336
   14137  347. https://gcc.gnu.org/PR21768
   14138  348. https://gcc.gnu.org/PR21853
   14139  349. https://gcc.gnu.org/PR21903
   14140  350. https://gcc.gnu.org/PR21983
   14141  351. https://gcc.gnu.org/PR21987
   14142  352. https://gcc.gnu.org/PR22153
   14143  353. https://gcc.gnu.org/PR22172
   14144  354. https://gcc.gnu.org/PR21286
   14145  355. https://gcc.gnu.org/PR22233
   14146  356. https://gcc.gnu.org/PR22508
   14147  357. https://gcc.gnu.org/PR22545
   14148  358. https://gcc.gnu.org/PR23528
   14149  359. https://gcc.gnu.org/PR23550
   14150  360. https://gcc.gnu.org/PR23586
   14151  361. https://gcc.gnu.org/PR23624
   14152  362. https://gcc.gnu.org/PR23639
   14153  363. https://gcc.gnu.org/PR23797
   14154  364. https://gcc.gnu.org/PR23965
   14155  365. https://gcc.gnu.org/PR24052
   14156  366. https://gcc.gnu.org/PR24580
   14157  367. https://gcc.gnu.org/PR24267
   14158  368. https://gcc.gnu.org/PR17810
   14159  369. https://gcc.gnu.org/PR17860
   14160  370. https://gcc.gnu.org/PR21709
   14161  371. https://gcc.gnu.org/PR21964
   14162  372. https://gcc.gnu.org/PR22167
   14163  373. https://gcc.gnu.org/PR22619
   14164  374. https://gcc.gnu.org/PR23241
   14165  375. https://gcc.gnu.org/PR23478
   14166  376. https://gcc.gnu.org/PR24470
   14167  377. https://gcc.gnu.org/PR24950
   14168  378. https://gcc.gnu.org/PR14400
   14169  379. https://gcc.gnu.org/PR14940
   14170  380. https://gcc.gnu.org/PR20239
   14171  381. https://gcc.gnu.org/PR15220
   14172  382. https://gcc.gnu.org/PR19275
   14173  383. https://gcc.gnu.org/PR21888
   14174  384. https://gcc.gnu.org/PR15342
   14175  385. https://gcc.gnu.org/PR23985
   14176  386. https://gcc.gnu.org/PR16719
   14177  387. https://gcc.gnu.org/PR21723
   14178  388. https://gcc.gnu.org/PR21841
   14179  389. https://gcc.gnu.org/PR23644
   14180  390. https://gcc.gnu.org/PR24718
   14181  391. https://gcc.gnu.org/PR18421
   14182  392. https://gcc.gnu.org/PR20621
   14183  393. https://gcc.gnu.org/PR18583
   14184  394. https://gcc.gnu.org/PR20191
   14185  395. https://gcc.gnu.org/PR22083
   14186  396. https://gcc.gnu.org/PR23070
   14187  397. https://gcc.gnu.org/PR23404
   14188  398. https://gcc.gnu.org/PR23539
   14189  399. https://gcc.gnu.org/PR24102
   14190  400. https://gcc.gnu.org/PR24465
   14191  401. https://gcc.gnu.org/PR19933
   14192  402. https://gcc.gnu.org/PR21889
   14193  403. https://gcc.gnu.org/PR19300
   14194  404. https://gcc.gnu.org/PR20301
   14195  405. https://gcc.gnu.org/PR20673
   14196  406. https://gcc.gnu.org/PR18582
   14197  407. https://gcc.gnu.org/PR19340
   14198  408. https://gcc.gnu.org/PR21716
   14199  409. https://gcc.gnu.org/PR24315
   14200  410. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.4.6
   14201  411. https://gcc.gnu.org/onlinedocs/
   14202  412. mailto:gcc-help (a] gcc.gnu.org
   14203  413. mailto:gcc (a] gcc.gnu.org
   14204  414. https://gcc.gnu.org/lists.html
   14205  415. https://www.fsf.org/
   14206  416. https://gcc.gnu.org/about.html
   14207  417. http://validator.w3.org/check/referer
   14208 ======================================================================
   14209 http://gcc.gnu.org/gcc-3.3/index.html
   14210                              GCC 3.3 Release Series
   14211 
   14212    (This release series is no longer supported.)
   14213 
   14214    May 03, 2005
   14215 
   14216    The [1]GNU project and the GCC developers are pleased to announce the
   14217    release of GCC 3.3.6.
   14218 
   14219    This release is a bug-fix release, containing fixes for regressions in
   14220    GCC 3.3.5 relative to previous releases of GCC.
   14221 
   14222    This release is the last of the series 3.3.x.
   14223 
   14224    The GCC 3.3 release series includes numerous [2]new features,
   14225    improvements, bug fixes, and other changes, thanks to an [3]amazing
   14226    group of volunteers.
   14227 
   14228 Release History
   14229 
   14230    GCC 3.3.6
   14231           May 3, 2005 ([4]changes)
   14232 
   14233    GCC 3.3.5
   14234           September 30, 2004 ([5]changes)
   14235 
   14236    GCC 3.3.4
   14237           May 31, 2004 ([6]changes)
   14238 
   14239    GCC 3.3.3
   14240           February 14, 2004 ([7]changes)
   14241 
   14242    GCC 3.3.2
   14243           October 16, 2003 ([8]changes)
   14244 
   14245    GCC 3.3.1
   14246           August 8, 2003 ([9]changes)
   14247 
   14248    GCC 3.3
   14249           May 14, 2003 ([10]changes)
   14250 
   14251 References and Acknowledgements
   14252 
   14253    GCC used to stand for the GNU C Compiler, but since the compiler
   14254    supports several other languages aside from C, it now stands for the
   14255    GNU Compiler Collection.
   14256 
   14257    A list of [11]successful builds is updated as new information becomes
   14258    available.
   14259 
   14260    The GCC developers would like to thank the numerous people that have
   14261    contributed new features, improvements, bug fixes, and other changes as
   14262    well as test results to GCC. This [12]amazing group of volunteers is
   14263    what makes GCC successful.
   14264 
   14265    For additional information about GCC please refer to the [13]GCC
   14266    project web site or contact the [14]GCC development mailing list.
   14267 
   14268    To obtain GCC please use [15]our mirror sites, or our CVS server.
   14269 
   14270 
   14271     For questions related to the use of GCC, please consult these web
   14272     pages and the [16]GCC manuals. If that fails, the
   14273     [17]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   14274     web pages and the development of GCC are welcome on our developer
   14275     list at [18]gcc (a] gcc.gnu.org. All of [19]our lists have public
   14276     archives.
   14277 
   14278    Copyright (C) [20]Free Software Foundation, Inc. Verbatim copying and
   14279    distribution of this entire article is permitted in any medium,
   14280    provided this notice is preserved.
   14281 
   14282    These pages are [21]maintained by the GCC team. Last modified
   14283    2019-11-28[22].
   14284 
   14285 References
   14286 
   14287    1. http://www.gnu.org/
   14288    2. http://gcc.gnu.org/gcc-3.3/changes.html
   14289    3. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   14290    4. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6
   14291    5. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.5
   14292    6. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.4
   14293    7. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.3
   14294    8. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.2
   14295    9. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.1
   14296   10. http://gcc.gnu.org/gcc-3.3/changes.html
   14297   11. http://gcc.gnu.org/gcc-3.3/buildstat.html
   14298   12. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   14299   13. http://gcc.gnu.org/index.html
   14300   14. mailto:gcc (a] gcc.gnu.org
   14301   15. http://gcc.gnu.org/mirrors.html
   14302   16. https://gcc.gnu.org/onlinedocs/
   14303   17. mailto:gcc-help (a] gcc.gnu.org
   14304   18. mailto:gcc (a] gcc.gnu.org
   14305   19. https://gcc.gnu.org/lists.html
   14306   20. https://www.fsf.org/
   14307   21. https://gcc.gnu.org/about.html
   14308   22. http://validator.w3.org/check/referer
   14309 ======================================================================
   14310 http://gcc.gnu.org/gcc-3.3/changes.html
   14311                              GCC 3.3 Release Series
   14312                         Changes, New Features, and Fixes
   14313 
   14314    The latest release in the 3.3 release series is [1]GCC 3.3.6.
   14315 
   14316 Caveats
   14317 
   14318      * The preprocessor no longer accepts multi-line string literals. They
   14319        were deprecated in 3.0, 3.1, and 3.2.
   14320      * The preprocessor no longer supports the -A- switch when appearing
   14321        alone. -A- followed by an assertion is still supported.
   14322      * Support for all the systems [2]obsoleted in GCC 3.1 has been
   14323        removed from GCC 3.3. See below for a [3]list of systems which are
   14324        obsoleted in this release.
   14325      * Checking for null format arguments has been decoupled from the rest
   14326        of the format checking mechanism. Programs which use the format
   14327        attribute may regain this functionality by using the new [4]nonnull
   14328        function attribute. Note that all functions for which GCC has a
   14329        built-in format attribute, an appropriate built-in nonnull
   14330        attribute is also applied.
   14331      * The DWARF (version 1) debugging format has been deprecated and will
   14332        be removed in a future version of GCC. Version 2 of the DWARF
   14333        debugging format will continue to be supported for the foreseeable
   14334        future.
   14335      * The C and Objective-C compilers no longer accept the "Naming Types"
   14336        extension (typedef foo = bar); it was already unavailable in C++.
   14337        Code which uses it will need to be changed to use the "typeof"
   14338        extension instead: typedef typeof(bar) foo. (We have removed this
   14339        extension without a period of deprecation because it has caused the
   14340        compiler to crash since version 3.0 and no one noticed until very
   14341        recently. Thus we conclude it is not in widespread use.)
   14342      * The -traditional C compiler option has been removed. It was
   14343        deprecated in 3.1 and 3.2. (Traditional preprocessing remains
   14344        available.) The <varargs.h> header, used for writing variadic
   14345        functions in traditional C, still exists but will produce an error
   14346        message if used.
   14347      * GCC 3.3.1 automatically places zero-initialized variables in the
   14348        .bss section on some operating systems. Versions of GNU Emacs up to
   14349        (and including) 21.3 will not work correctly when using this
   14350        optimization; you can use -fno-zero-initialized-in-bss to disable
   14351        it.
   14352 
   14353 General Optimizer Improvements
   14354 
   14355      * A new scheme for accurately describing processor pipelines, the
   14356        [5]DFA scheduler, has been added.
   14357      * Pavel Nejedly, Charles University Prague, has contributed new file
   14358        format used by the edge coverage profiler (-fprofile-arcs).
   14359        The new format is robust and diagnoses common mistakes where
   14360        profiles from different versions (or compilations) of the program
   14361        are combined resulting in nonsensical profiles and slow code to
   14362        produced with profile feedback. Additionally this format allows
   14363        extra data to be gathered. Currently, overall statistics are
   14364        produced helping optimizers to identify hot spots of a program
   14365        globally replacing the old intra-procedural scheme and resulting in
   14366        better code. Note that the gcov tool from older GCC versions will
   14367        not be able to parse the profiles generated by GCC 3.3 and vice
   14368        versa.
   14369      * Jan Hubicka, SuSE Labs, has contributed a new superblock formation
   14370        pass enabled using -ftracer. This pass simplifies the control flow
   14371        of functions allowing other optimizations to do better job.
   14372        He also contributed the function reordering pass
   14373        (-freorder-functions) to optimize function placement using profile
   14374        feedback.
   14375 
   14376 New Languages and Language specific improvements
   14377 
   14378   C/ObjC/C++
   14379 
   14380      * The preprocessor now accepts directives within macro arguments. It
   14381        processes them just as if they had not been within macro arguments.
   14382      * The separate ISO and traditional preprocessors have been completely
   14383        removed. The front end handles either type of preprocessed output
   14384        if necessary.
   14385      * In C99 mode preprocessor arithmetic is done in the precision of the
   14386        target's intmax_t, as required by that standard.
   14387      * The preprocessor can now copy comments inside macros to the output
   14388        file when the macro is expanded. This feature, enabled using the
   14389        -CC option, is intended for use by applications which place
   14390        metadata or directives inside comments, such as lint.
   14391      * The method of constructing the list of directories to be searched
   14392        for header files has been revised. If a directory named by a -I
   14393        option is a standard system include directory, the option is
   14394        ignored to ensure that the default search order for system
   14395        directories and the special treatment of system header files are
   14396        not defeated.
   14397      * A few more [6]ISO C99 features now work correctly.
   14398      * A new function attribute, nonnull, has been added which allows
   14399        pointer arguments to functions to be specified as requiring a
   14400        non-null value. The compiler currently uses this information to
   14401        issue a warning when it detects a null value passed in such an
   14402        argument slot.
   14403      * A new type attribute, may_alias, has been added. Accesses to
   14404        objects with types with this attribute are not subjected to
   14405        type-based alias analysis, but are instead assumed to be able to
   14406        alias any other type of objects, just like the char type.
   14407 
   14408   C++
   14409 
   14410      * Type based alias analysis has been implemented for C++ aggregate
   14411        types.
   14412 
   14413   Objective-C
   14414 
   14415      * Generate an error if Objective-C objects are passed by value in
   14416        function and method calls.
   14417      * When -Wselector is used, check the whole list of selectors at the
   14418        end of compilation, and emit a warning if a @selector() is not
   14419        known.
   14420      * Define __NEXT_RUNTIME__ when compiling for the NeXT runtime.
   14421      * No longer need to include objc/objc-class.h to compile self calls
   14422        in class methods (NeXT runtime only).
   14423      * New -Wundeclared-selector option.
   14424      * Removed selector bloating which was causing object files to be 10%
   14425        bigger on average (GNU runtime only).
   14426      * Using at run time @protocol() objects has been fixed in certain
   14427        situations (GNU runtime only).
   14428      * Type checking has been fixed and improved in many situations
   14429        involving protocols.
   14430 
   14431   Java
   14432 
   14433      * The java.sql and javax.sql packages now implement the JDBC 3.0 (JDK
   14434        1.4) API.
   14435      * The JDK 1.4 assert facility has been implemented.
   14436      * The bytecode interpreter is now direct threaded and thus faster.
   14437 
   14438   Fortran
   14439 
   14440      * Fortran improvements are listed in [7]the Fortran documentation.
   14441 
   14442   Ada
   14443 
   14444      * Ada tasking now works with glibc 2.3.x threading libraries.
   14445 
   14446 New Targets and Target Specific Improvements
   14447 
   14448      * The following changes have been made to the HP-PA port:
   14449           + The port now defaults to scheduling for the PA8000 series of
   14450             processors.
   14451           + Scheduling support for the PA7300 processor has been added.
   14452           + The 32-bit port now supports weak symbols under HP-UX 11.
   14453           + The handling of initializers and finalizers has been improved
   14454             under HP-UX 11. The 64-bit port no longer uses collect2.
   14455           + Dwarf2 EH support has been added to the 32-bit GNU/Linux port.
   14456           + ABI fixes to correct the passing of small structures by value.
   14457      * The SPARC, HP-PA, SH4, and x86/pentium ports have been converted to
   14458        use the DFA processor pipeline description.
   14459      * The following NetBSD configurations for the SuperH processor family
   14460        have been added:
   14461           + SH3, big-endian, sh-*-netbsdelf*
   14462           + SH3, little-endian, shle-*-netbsdelf*
   14463           + SH5, SHmedia, big-endian, 32-bit default, sh5-*-netbsd*
   14464           + SH5, SHmedia, little-endian, 32-bit default, sh5le-*-netbsd*
   14465           + SH5, SHmedia, big-endian, 64-bit default, sh64-*-netbsd*
   14466           + SH5, SHmedia, little-endian, 64-bit default, sh64le-*-netbsd*
   14467      * The following changes have been made to the IA-32/x86-64 port:
   14468           + SSE2 and 3dNOW! intrinsics are now supported.
   14469           + Support for thread local storage has been added to the IA-32
   14470             and x86-64 ports.
   14471           + The x86-64 port has been significantly improved.
   14472      * The following changes have been made to the MIPS port:
   14473           + All configurations now accept the -mabi switch. Note that you
   14474             will need appropriate multilibs for this option to work
   14475             properly.
   14476           + ELF configurations will always pass an ABI flag to the
   14477             assembler, except when the MIPS EABI is selected.
   14478           + -mabi=64 no longer selects MIPS IV code.
   14479           + The -mcpu option, which was deprecated in 3.1 and 3.2, has
   14480             been removed from this release.
   14481           + -march now changes the core ISA level. In previous releases,
   14482             it would change the use of processor-specific extensions, but
   14483             would leave the core ISA unchanged. For example, mips64-elf
   14484             -march=r8000 will now generate MIPS IV code.
   14485           + Under most configurations, -mipsN now acts as a synonym for
   14486             -march.
   14487           + There are some new preprocessor macros to describe the -march
   14488             and -mtune settings. See the documentation of those options
   14489             for details.
   14490           + Support for the NEC VR-Series processors has been added. This
   14491             includes the 54xx, 5500, and 41xx series.
   14492           + Support for the Sandcraft sr71k processor has been added.
   14493      * The following changes have been made to the S/390 port:
   14494           + Support to build the Java runtime libraries has been added.
   14495             Java is now enabled by default on s390-*-linux* and
   14496             s390x-*-linux* targets.
   14497           + Multilib support for the s390x-*-linux* target has been added;
   14498             this allows to build 31-bit binaries using the -m31 option.
   14499           + Support for thread local storage has been added.
   14500           + Inline assembler code may now use the 'Q' constraint to
   14501             specify memory operands without index register.
   14502           + Various platform-specific performance improvements have been
   14503             implemented; in particular, the compiler now uses the BRANCH
   14504             ON COUNT family of instructions and makes more frequent use of
   14505             the TEST UNDER MASK family of instructions.
   14506      * The following changes have been made to the PowerPC port:
   14507           + Support for IBM Power4 processor added.
   14508           + Support for Motorola e500 SPE added.
   14509           + Support for AIX 5.2 added.
   14510           + Function and Data sections now supported on AIX.
   14511           + Sibcall optimizations added.
   14512      * The support for H8 Tiny is added to the H8/300 port with -mn.
   14513 
   14514 Obsolete Systems
   14515 
   14516    Support for a number of older systems has been declared obsolete in GCC
   14517    3.3. Unless there is activity to revive them, the next release of GCC
   14518    will have their sources permanently removed.
   14519 
   14520    All configurations of the following processor architectures have been
   14521    declared obsolete:
   14522      * Matsushita MN10200, mn10200-*-*
   14523      * Motorola 88000, m88k-*-*
   14524      * IBM ROMP, romp-*-*
   14525 
   14526    Also, some individual systems have been obsoleted:
   14527      * Alpha
   14528           + Interix, alpha*-*-interix*
   14529           + Linux libc1, alpha*-*-linux*libc1*
   14530           + Linux ECOFF, alpha*-*-linux*ecoff*
   14531      * ARM
   14532           + Generic a.out, arm*-*-aout*
   14533           + Conix, arm*-*-conix*
   14534           + "Old ABI," arm*-*-oabi
   14535           + StrongARM/COFF, strongarm-*-coff*
   14536      * HPPA (PA-RISC)
   14537           + Generic OSF, hppa1.0-*-osf*
   14538           + Generic BSD, hppa1.0-*-bsd*
   14539           + HP/UX versions 7, 8, and 9, hppa1.[01]-*-hpux[789]*
   14540           + HiUX, hppa*-*-hiux*
   14541           + Mach Lites, hppa*-*-lites*
   14542      * Intel 386 family
   14543           + Windows NT 3.x, i?86-*-win32
   14544      * MC68000 family
   14545           + HP systems, m68000-hp-bsd* and m68k-hp-bsd*
   14546           + Sun systems, m68000-sun-sunos*, m68k-sun-sunos*, and
   14547             m68k-sun-mach*
   14548           + AT&T systems, m68000-att-sysv*
   14549           + Atari systems, m68k-atari-sysv*
   14550           + Motorola systems, m68k-motorola-sysv*
   14551           + NCR systems, m68k-ncr-sysv*
   14552           + Plexus systems, m68k-plexus-sysv*
   14553           + Commodore systems, m68k-cbm-sysv*
   14554           + Citicorp TTI, m68k-tti-*
   14555           + Unos, m68k-crds-unos*
   14556           + Concurrent RTU, m68k-ccur-rtu*
   14557           + Linux a.out, m68k-*-linux*aout*
   14558           + Linux libc1, m68k-*-linux*libc1*
   14559           + pSOS, m68k-*-psos*
   14560      * MIPS
   14561           + Generic ECOFF, mips*-*-ecoff*
   14562           + SINIX, mips-sni-sysv4
   14563           + Orion RTEMS, mips64orion-*-rtems*
   14564      * National Semiconductor 32000
   14565           + OpenBSD, ns32k-*-openbsd*
   14566      * POWER (aka RS/6000) and PowerPC
   14567           + AIX versions 1, 2, and 3, rs6000-ibm-aix[123]*
   14568           + Bull BOSX, rs6000-bull-bosx
   14569           + Generic Mach, rs6000-*-mach*
   14570           + Generic SysV, powerpc*-*-sysv*
   14571           + Linux libc1, powerpc*-*-linux*libc1*
   14572      * Sun SPARC
   14573           + Generic a.out, sparc-*-aout*, sparclet-*-aout*,
   14574             sparclite-*-aout*, and sparc86x-*-aout*
   14575           + NetBSD a.out, sparc-*-netbsd*aout*
   14576           + Generic BSD, sparc-*-bsd*
   14577           + ChorusOS, sparc-*-chorusos*
   14578           + Linux a.out, sparc-*-linux*aout*
   14579           + Linux libc1, sparc-*-linux*libc1*
   14580           + LynxOS, sparc-*-lynxos*
   14581           + Solaris on HAL hardware, sparc-hal-solaris2*
   14582           + SunOS versions 3 and 4, sparc-*-sunos[34]*
   14583      * NEC V850
   14584           + RTEMS, v850-*-rtems*
   14585      * VAX
   14586           + VMS, vax-*-vms*
   14587 
   14588 Documentation improvements
   14589 
   14590 Other significant improvements
   14591 
   14592      * Almost all front-end dependencies in the compiler have been
   14593        separated out into a set of language hooks. This should make adding
   14594        a new front end clearer and easier.
   14595      * One effect of removing the separate preprocessor is a small
   14596        increase in the robustness of the compiler in general, and the
   14597        maintainability of target descriptions. Previously target-specific
   14598        built-in macros and others, such as __FAST_MATH__, had to be
   14599        handled with so-called specs that were hard to maintain. Often they
   14600        would fail to behave properly when conflicting options were
   14601        supplied on the command line, and define macros in the user's
   14602        namespace even when strict ISO compliance was requested.
   14603        Integrating the preprocessor has cleanly solved these issues.
   14604      * The Makefile suite now supports redirection of make install by
   14605        means of the variable DESTDIR.
   14606      __________________________________________________________________
   14607 
   14608 GCC 3.3
   14609 
   14610    Detailed release notes for the GCC 3.3 release follow.
   14611 
   14612   Bug Fixes
   14613 
   14614     bootstrap failures
   14615 
   14616      * [8]10140 cross compiler build failures: missing __mempcpy (DUP:
   14617        [9]10198,[10]10338)
   14618 
   14619     Internal compiler errors (multi-platform)
   14620 
   14621      * [11]3581 large string causes segmentation fault in cc1
   14622      * [12]4382 __builtin_{set,long}jmp with -O3 can crash the compiler
   14623      * [13]5533 (c++) ICE when processing std::accumulate(begin, end,
   14624        init, invalid_op)
   14625      * [14]6387 -fpic -gdwarf-2 -g1 combination gives ICE in dwarf2out
   14626      * [15]6412 (c++) ICE in retrieve_specialization
   14627      * [16]6620 (c++) partial template specialization causes an ICE
   14628        (segmentation fault)
   14629      * [17]6663 (c++) ICE with attribute aligned
   14630      * [18]7068 ICE with incomplete types
   14631      * [19]7083 (c++) ICE using -gstabs with dodgy class derivation
   14632      * [20]7647 (c++) ICE when data member has the name of the enclosing
   14633        class
   14634      * [21]7675 ICE in fixup_var_refs_1
   14635      * [22]7718 'complex' template instantiation causes ICE
   14636      * [23]8116 (c++) ICE in member template function
   14637      * [24]8358 (ada) Ada compiler accesses freed memory, crashes
   14638      * [25]8511 (c++) ICE: (hopefully) reproducible cc1plus segmentation
   14639        fault
   14640      * [26]8564 (c++) ICE in find_function_data, in function.c
   14641      * [27]8660 (c++) template overloading ICE in tsubst_expr, in cp/pt.c
   14642      * [28]8766 (c++) ICE after failed initialization of static template
   14643        variable
   14644      * [29]8803 ICE in instantiate_virtual_regs_1, in function.c
   14645      * [30]8846 (c++) ICE after diagnostic if fr_FR@euro locale is set
   14646      * [31]8906 (c++) ICE (Segmentation fault) when parsing nested-class
   14647        definition
   14648      * [32]9216 (c++) ICE on missing template parameter
   14649      * [33]9261 (c++) ICE in arg_assoc, in cp/decl2.c
   14650      * [34]9263 (fortran) ICE caused by invalid PARAMETER in implied DO
   14651        loop
   14652      * [35]9429 (c++) ICE in template instantiation with a pointered new
   14653        operator
   14654      * [36]9516 Internal error when using a big array
   14655      * [37]9600 (c++) ICE with typedefs in template class
   14656      * [38]9629 (c++) virtual inheritance segfault
   14657      * [39]9672 (c++) ICE: Error reporting routines re-entered
   14658      * [40]9749 (c++) ICE in write_expression on invalid function
   14659        prototype
   14660      * [41]9794 (fortran) ICE: floating point exception during constant
   14661        folding
   14662      * [42]9829 (c++) Missing colon in nested namespace usage causes ICE
   14663      * [43]9916 (c++) ICE with noreturn function in ?: statement
   14664      * [44]9936 ICE with local function and variable-length 2d array
   14665      * [45]10262 (c++) cc1plus crashes with large generated code
   14666      * [46]10278 (c++) ICE in parser for invalid code
   14667      * [47]10446 (c++) ICE on definition of nonexistent member function of
   14668        nested class in a class template
   14669      * [48]10451 (c++) ICE in grokdeclarator on spurious mutable
   14670        declaration
   14671      * [49]10506 (c++) ICE in build_new at cp/init.c with
   14672        -fkeep-inline-functions and multiple inheritance
   14673      * [50]10549 (c++) ICE in store_bit_field on bitfields that exceed the
   14674        precision of the declared type
   14675 
   14676     Optimization bugs
   14677 
   14678      * [51]2001 Inordinately long compile times in reload CSE regs
   14679      * [52]2391 Exponential compilation time explosion in combine
   14680      * [53]2960 Duplicate loop conditions even with -Os
   14681      * [54]4046 redundant conditional branch
   14682      * [55]6405 Loop-unrolling related performance regressions
   14683      * [56]6798 very long compile time with large case-statement
   14684      * [57]6871 const objects shouldn't be moved to .bss
   14685      * [58]6909 problem w/ -Os on modified loop-2c.c test case
   14686      * [59]7189 gcc -O2 -Wall does not print ``control reaches end of
   14687        non-void function'' warning
   14688      * [60]7642 optimization problem with signbit()
   14689      * [61]8634 incorrect code for inlining of memcpy under -O2
   14690      * [62]8750 Cygwin prolog generation erroneously emitting __alloca as
   14691        regular function call
   14692 
   14693     C front end
   14694 
   14695      * [63]2161 long if-else cascade overflows parser stack
   14696      * [64]4319 short accepted on typedef'd char
   14697      * [65]8602 incorrect line numbers in warning messages when using
   14698        inline functions
   14699      * [66]9177 -fdump-translation-unit: C front end deletes function_decl
   14700        AST nodes and breaks debugging dumps
   14701      * [67]9853 miscompilation of non-constant structure initializer
   14702 
   14703     c++ compiler and library
   14704 
   14705      * [68]45 legal template specialization code is rejected (DUP:
   14706        [69]3784)
   14707      * [70]764 lookup failure: friend operator and dereferencing a pointer
   14708        and templates (DUP: [71]5116)
   14709      * [72]2862 gcc accepts invalid explicit instantiation syntax (DUP:
   14710        2863)
   14711      * [73]3663 G++ doesn't check access control during template
   14712        instantiation
   14713      * [74]3797 gcc fails to emit explicit specialization of a template
   14714        member
   14715      * [75]3948 Two destructors are called when no copy destructor is
   14716        defined (ABI change)
   14717      * [76]4137 Conversion operator within template is not accepted
   14718      * [77]4361 bogus ambiguity taking the address of a member template
   14719      * [78]4802 g++ accepts illegal template code (access to private
   14720        member; DUP: [79]5837)
   14721      * [80]4803 inline function is used but never defined, and g++ does
   14722        not object
   14723      * [81]5094 Partial specialization cannot be friend?
   14724      * [82]5730 complex<double>::norm() -- huge slowdown from egcs-2.91.66
   14725      * [83]6713 Regression wrt 3.0.4: g++ -O2 leads to seg fault at run
   14726        time
   14727      * [84]7015 certain __asm__ constructs rejected
   14728      * [85]7086 compile time regression (quadratic behavior in
   14729        fixup_var_refs)
   14730      * [86]7099 G++ doesn't set the noreturn attribute on std::exit and
   14731        std::abort
   14732      * [87]7247 copy constructor missing when inlining enabled (invalid
   14733        optimization?)
   14734      * [88]7441 string array initialization compilation time regression
   14735        from seconds to minutes
   14736      * [89]7768 __PRETTY_FUNCTION__ for template destructor is wrong
   14737      * [90]7804 bad printing of floating point constant in warning message
   14738      * [91]8099 Friend classes and template specializations
   14739      * [92]8117 member function pointers and multiple inheritance
   14740      * [93]8205 using declaration and multiple inheritance
   14741      * [94]8645 unnecessary non-zero checks in stl_tree.h
   14742      * [95]8724 explicit destructor call for incomplete class allowed
   14743      * [96]8805 compile time regression with many member variables
   14744      * [97]8691 -O3 and -fno-implicit-templates are incompatible
   14745      * [98]8700 unhelpful error message for binding temp to reference
   14746      * [99]8724 explicit destructor call for incomplete class allowed
   14747      * [100]8949 numeric_limits<>::denorm_min() and is_iec559 problems
   14748      * [101]9016 Failure to consistently constant fold "constant" C++
   14749        objects
   14750      * [102]9053 g++ confused about ambiguity of overloaded function
   14751        templates
   14752      * [103]9152 undefined virtual thunks
   14753      * [104]9182 basic_filebuf<> does not report errors in codecvt<>::out
   14754      * [105]9297 data corruption due to codegen bug (when copying.)
   14755      * [106]9318 i/ostream::operator>>/<<(streambuf*) broken
   14756      * [107]9320 Incorrect usage of traits_type::int_type in stdio_filebuf
   14757      * [108]9400 bogus -Wshadow warning: shadowed declaration of this in
   14758        local classes
   14759      * [109]9424 i/ostream::operator>>/<<(streambuf*) drops characters
   14760      * [110]9425 filebuf::pbackfail broken (DUP: [111]9439)
   14761      * [112]9474 GCC freezes in compiling a weird code mixing <iostream>
   14762        and <iostream.h>
   14763      * [113]9548 Incorrect results from setf(ios::fixed) and precision(-1)
   14764        [114][DR 231]
   14765      * [115]9555 ostream inserters fail to set badbit on exception
   14766      * [116]9561 ostream inserters rethrow exception of wrong type
   14767      * [117]9563 ostream::sentry returns true after a failed preparation
   14768      * [118]9582 one-definition rule violation in std::allocator
   14769      * [119]9622 __PRETTY_FUNCTION__ incorrect in template destructors
   14770      * [120]9683 bug in initialization chains for static const variables
   14771        from template classes
   14772      * [121]9791 -Woverloaded-virtual reports hiding of destructor
   14773      * [122]9817 collate::compare doesn't handle nul characters
   14774      * [123]9825 filebuf::sputbackc breaks sbumpc
   14775      * [124]9826 operator>>(basic_istream, basic_string) fails to compile
   14776        with custom traits
   14777      * [125]9924 Multiple using statements for builtin functions not
   14778        allowed
   14779      * [126]9946 destructor is not called for temporary object
   14780      * [127]9964 filebuf::close() sometimes fails to close file
   14781      * [128]9988 filebuf::overflow writes EOF to file
   14782      * [129]10033 optimization breaks polymorphic references w/ typeid
   14783        operator
   14784      * [130]10097 filebuf::underflow drops characters
   14785      * [131]10132 filebuf destructor can throw exceptions
   14786      * [132]10180 gcc fails to warn about non-inlined function
   14787      * [133]10199 method parametrized by template does not work everywhere
   14788      * [134]10300 use of array-new (nothrow) in segfaults on NULL return
   14789      * [135]10427 Stack corruption with variable-length automatic arrays
   14790        and virtual destructors
   14791      * [136]10503 Compilation never stops in fixed_type_or_null
   14792 
   14793     Objective-C
   14794 
   14795      * [137]5956 selectors aren't matched properly when added to the
   14796        selector table
   14797 
   14798     Fortran compiler and library
   14799 
   14800      * [138]1832 list directed i/o overflow hangs, -fbounds-check doesn't
   14801        detect
   14802      * [139]3924 g77 generates code that is rejected by GAS if COFF debug
   14803        info requested
   14804      * [140]5634 doc: explain that configure --prefix=~/... does not work
   14805      * [141]6367 multiple repeat counts confuse namelist read into array
   14806      * [142]6491 Logical operations error on logicals when using
   14807        -fugly-logint
   14808      * [143]6742 Generation of C++ Prototype for FORTRAN and extern "C"
   14809      * [144]7113 Failure of g77.f-torture/execute/f90-intrinsic-bit.f -Os
   14810        on irix6.5
   14811      * [145]7236 OPEN(...,RECL=nnn,...) without ACCESS='DIRECT' should
   14812        assume a direct access file
   14813      * [146]7278 g77 "bug"; the executable misbehaves (with -O2
   14814        -fno-automatic)
   14815      * [147]7384 DATE_AND_TIME milliseconds field inactive on Windows
   14816      * [148]7388 Incorrect output with 0-based array of characters
   14817      * [149]8587 Double complex zero ** double precision number -> NaN
   14818        instead of zero
   14819      * [150]9038 -ffixed-line-length-none -x f77-cpp-input gives: Warning:
   14820        unknown register name line-length-none
   14821      * [151]10197 Direct access files not unformatted by default
   14822 
   14823     Java compiler and library
   14824 
   14825      * [152]6005 gcj fails to build rhug on alpha
   14826      * [153]6389 System.getProperty("") should always throw an
   14827        IllegalArgumentException
   14828      * [154]6576 java.util.ResourceBundle.getResource ignores locale
   14829      * [155]6652 new java.io.File("").getCanonicalFile() throws exception
   14830      * [156]7060 getMethod() doesn't search super interface
   14831      * [157]7073 bytecode interpreter gives wrong answer for interface
   14832        getSuperclass()
   14833      * [158]7180 possible bug in
   14834        javax.naming.spi.NamingManager.getPlusPath()
   14835      * [159]7416 java.security startup refs "GNU libgcj.security"
   14836      * [160]7570 Runtime.exec with null envp: child doesn't inherit parent
   14837        env (DUP: [161]7578)
   14838      * [162]7611 Internal error while compiling libjava with -O
   14839      * [163]7709 NullPointerException in _Jv_ResolvePoolEntry
   14840      * [164]7766 ZipInputStream.available returns 0 immediately after
   14841        construction
   14842      * [165]7785 Calendar.getTimeInMillis/setTimeInMillis should be public
   14843      * [166]7786 TimeZone.getDSTSavings() from JDK1.4 not implemented
   14844      * [167]8142 '$' in class names vs. dlopen 'dynamic string tokens'
   14845      * [168]8234 ZipInputStream chokes when InputStream.read() returns
   14846        small chunks
   14847      * [169]8415 reflection bug: exception info for Method
   14848      * [170]8481 java.Random.nextInt(int) may return negative
   14849      * [171]8593 Error reading GZIPped files with BufferedReader
   14850      * [172]8759 java.beans.Introspector has no flushCaches() or
   14851        flushFromCaches() methods
   14852      * [173]8997 spin() calls Thread.sleep
   14853      * [174]9253 on win32, java.io.File.listFiles("C:\\") returns pwd
   14854        instead of the root content of C:
   14855      * [175]9254 java::lang::Object::wait(), threads-win32.cc returns
   14856        wrong return codes
   14857      * [176]9271 Severe bias in java.security.SecureRandom
   14858 
   14859     Ada compiler and library
   14860 
   14861      * [177]6767 make gnatlib-shared fails on -laddr2line
   14862      * [178]9911 gnatmake fails to link when GCC configured with
   14863        --with-sjlj-exceptions=yes
   14864      * [179]10020 Can't bootstrap gcc on AIX with Ada enabled
   14865      * [180]10546 Ada tasking not working on Red Hat 9
   14866 
   14867     preprocessor
   14868 
   14869      * [181]7029 preprocessor should ignore #warning with -M
   14870 
   14871     ARM-specific
   14872 
   14873      * [182]2903 [arm] Optimization bug with long long arithmetic
   14874      * [183]7873 arm-linux-gcc fails when assigning address to a bit field
   14875 
   14876     FreeBSD-specific
   14877 
   14878      * [184]7680 float functions undefined in math.h/cmath with #define
   14879        _XOPEN_SOURCE
   14880 
   14881     HP-UX or HP-PA-specific
   14882 
   14883      * [185]8705 [HP-PA] ICE in emit_move_insn_1, in expr.c
   14884      * [186]9986 [HP-UX] Incorrect transformation of fputs_unlocked to
   14885        fputc_unlocked
   14886      * [187]10056 [HP-PA] ICE at -O2 when building c++ code from doxygen
   14887 
   14888     m68hc11-specific
   14889 
   14890      * [188]6744 Bad assembler code generated: reference to pseudo
   14891        register z
   14892      * [189]7361 Internal compiler error in reload_cse_simplify_operands,
   14893        in reload1.c
   14894 
   14895     MIPS-specific
   14896 
   14897      * [190]9496 [mips-linux] bug in optimizer?
   14898 
   14899     PowerPC-specific
   14900 
   14901      * [191]7067 -Os with -mcpu=powerpc optimizes for speed (?) instead of
   14902        space
   14903      * [192]8480 reload ICEs for LAPACK code on powerpc64-linux
   14904      * [193]8784 [AIX] Internal compiler error in simplify_gen_subreg
   14905      * [194]10315 [powerpc] ICE: in extract_insn, in recog.c
   14906 
   14907     SPARC-specific
   14908 
   14909      * [195]10267 (documentation) Wrong build instructions for
   14910        *-*-solaris2*
   14911 
   14912     x86-specific (Intel/AMD)
   14913 
   14914      * [196]7916 ICE in instantiate_virtual_register_1
   14915      * [197]7926 (c++) i486 instructions in header files make c++ programs
   14916        crash on i386
   14917      * [198]8555 ICE in gen_split_1231
   14918      * [199]8994 ICE with -O -march=pentium4
   14919      * [200]9426 ICE with -fssa -funroll-loops -fprofile-arcs
   14920      * [201]9806 ICE in inline assembly with -fPIC flag
   14921      * [202]10077 gcc -msse2 generates movd to move dwords between xmm
   14922        regs
   14923      * [203]10233 64-bit comparison only comparing bottom 32-bits
   14924      * [204]10286 type-punning doesn't work with __m64 and -O
   14925      * [205]10308 [x86] ICE with -O -fgcse or -O2
   14926      __________________________________________________________________
   14927 
   14928 GCC 3.3.1
   14929 
   14930   Bug Fixes
   14931 
   14932    This section lists the problem reports (PRs) from GCC's bug tracking
   14933    system that are known to be fixed in the 3.3.1 release. This list might
   14934    not be complete (that is, it is possible that some PRs that have been
   14935    fixed are not listed here).
   14936 
   14937     Bootstrap failures
   14938 
   14939      * [206]11272 [Solaris] make bootstrap fails while building libstdc++
   14940 
   14941     Internal compiler errors (multi-platform)
   14942 
   14943      * [207]5754 ICE on invalid nested template class
   14944      * [208]6597 ICE in set_mem_alias_set compiling Qt with -O2 on ia64
   14945        and --enable-checking
   14946      * [209]6949 (c++) ICE in tsubst_decl, in cp/pt.c
   14947      * [210]7053 (c++) ICE when declaring a function already defined as a
   14948        friend method of a template class
   14949      * [211]8164 (c++) ICE when using different const expressions as
   14950        template parameter
   14951      * [212]8384 (c++) ICE in is_base_type, in dwarf2out.c
   14952      * [213]9559 (c++) ICE with invalid initialization of a static const
   14953      * [214]9649 (c++) ICE in finish_member_declaration, in cp/semantics.c
   14954        when redeclaring a static member variable
   14955      * [215]9864 (fortran) ICE in add_abstract_origin_attribute, in
   14956        dwarfout.c with -g -O -finline-functions
   14957      * [216]10432 (c++) ICE in poplevel, in cp/decl.c
   14958      * [217]10475 ICE in subreg_highpart_offset for code with long long
   14959      * [218]10635 (c++) ICE when dereferencing an incomplete type casted
   14960        from a void pointer
   14961      * [219]10661 (c++) ICE in instantiate_decl, in cp/pt.c while
   14962        instantiating static member variables
   14963      * [220]10700 ICE in copy_to_mode_reg on 64-bit targets
   14964      * [221]10712 (c++) ICE in constructor_name_full, in cp/decl2.c
   14965      * [222]10796 (c++) ICE when defining an enum with two values: -1 and
   14966        MAX_INT_64BIT
   14967      * [223]10890 ICE in merge_assigned_reloads building Linux 2.4.2x
   14968        sched.c
   14969      * [224]10939 (c++) ICE with template code
   14970      * [225]10956 (c++) ICE when specializing a template member function
   14971        of a template class, in tsubst, in cp/pt.c
   14972      * [226]11041 (c++) ICE: const myclass &x = *x; (when operator*()
   14973        defined)
   14974      * [227]11059 (c++) ICE with empty union
   14975      * [228]11083 (c++) ICE in commit_one_edge_insertion, in cfgrtl.c with
   14976        -O2 -fnon-call-exceptions
   14977      * [229]11105 (c++) ICE in mangle_conv_op_name_for_type
   14978      * [230]11149 (c++) ICE on error when instantiation with call function
   14979        of a base type
   14980      * [231]11228 (c++) ICE on new-expression using array operator new and
   14981        default-initialization
   14982      * [232]11282 (c++) Infinite memory usage after syntax error
   14983      * [233]11301 (fortran) ICE with -fno-globals
   14984      * [234]11308 (c++) ICE when using an enum type name as if it were a
   14985        class or namespace
   14986      * [235]11473 (c++) ICE with -gstabs when empty struct inherits from
   14987        an empty struct
   14988      * [236]11503 (c++) ICE when instantiating template with ADDR_EXPR
   14989      * [237]11513 (c++) ICE in push_template_decl_real, in cp/pt.c:
   14990        template member functions
   14991 
   14992     Optimization bugs
   14993 
   14994      * [238]11198 -O2 -frename-registers generates wrong code (aliasing
   14995        problem)
   14996      * [239]11304 Wrong code production with -fomit-frame-pointer
   14997      * [240]11381 volatile memory access optimized away
   14998      * [241]11536 [strength-reduce] -O2 optimization produces wrong code
   14999      * [242]11557 constant folding bug generates wrong code
   15000 
   15001     C front end
   15002 
   15003      * [243]5897 No warning for statement after return
   15004      * [244]11279 DWARF-2 output mishandles large enums
   15005 
   15006     Preprocessor bugs
   15007 
   15008      * [245]11022 no warning for non-compatible macro redefinition
   15009 
   15010     C++ compiler and library
   15011 
   15012      * [246]2330 static_cast<>() to a private base is allowed
   15013      * [247]5388 Incorrect message "operands to ?: have different types"
   15014      * [248]5390 Libiberty fails to demangle multi-digit template
   15015        parameters
   15016      * [249]7877 Incorrect parameter passing to specializations of member
   15017        function templates
   15018      * [250]9393 Anonymous namespaces and compiling the same file twice
   15019      * [251]10032 -pedantic converts some errors to warnings
   15020      * [252]10468 const typeof(x) is non-const, but only in templates
   15021      * [253]10527 confused error message with "new int()" parameter
   15022        initializer
   15023      * [254]10679 parameter MIN_INLINE_INSNS is not honored
   15024      * [255]10682 gcc chokes on a typedef for an enum inside a class
   15025        template
   15026      * [256]10689 pow(std::complex(0),1/3) returns (nan, nan) instead of
   15027        0.
   15028      * [257]10845 template member function (with nested template as
   15029        parameter) cannot be called anymore if another unrelated template
   15030        member function is defined
   15031      * [258]10849 Cannot define an out-of-class specialization of a
   15032        private nested template class
   15033      * [259]10888 Suppress -Winline warnings for system headers
   15034      * [260]10929 -Winline warns about functions for which no definition
   15035        is visible
   15036      * [261]10931 valid conversion static_cast<const unsigned
   15037        int&>(lvalue-of-type-int) is rejected
   15038      * [262]10940 Bad code with explicit specialization
   15039      * [263]10968 If member function implicitly instantiated, explicit
   15040        instantiation of class fails to instantiate it
   15041      * [264]10990 Cannot convert with dynamic_cast<> to a private base
   15042        class from within a member function
   15043      * [265]11039 Bad interaction between implicit typename deprecation
   15044        and friendship
   15045      * [266]11062 (libstdc++) avoid __attribute__ ((unused)); say
   15046        "__unused__" instead
   15047      * [267]11095 C++ iostream manipulator causes segfault when called
   15048        with negative argument
   15049      * [268]11098 g++ doesn't emit complete debugging information for
   15050        local variables in destructors
   15051      * [269]11137 GNU/Linux shared library constructors not called unless
   15052        there's one global object
   15053      * [270]11154 spurious ambiguity report for template class
   15054        specialization
   15055      * [271]11329 Compiler cannot find user defined implicit typecast
   15056      * [272]11332 Spurious error with casts in ?: expression
   15057      * [273]11431 static_cast behavior with subclasses when default
   15058        constructor available
   15059      * [274]11528 money_get facet does not accept "$.00" as valid
   15060      * [275]11546 Type lookup problems in out-of-line definition of a
   15061        class doubly nested from a template class
   15062      * [276]11567 C++ code containing templated member function with same
   15063        name as pure virtual member function results in linking failure
   15064      * [277]11645 Failure to deal with using and private inheritance
   15065 
   15066     Java compiler and library
   15067 
   15068      * [278]5179 Qualified static field access doesn't initialize its
   15069        class
   15070      * [279]8204 gcj -O2 to native reorders certain instructions
   15071        improperly
   15072      * [280]10838 java.io.ObjectInputStream syntax error
   15073      * [281]10886 The RMI registry that comes with GCJ does not work
   15074        correctly
   15075      * [282]11349 JNDI URL context factories not located correctly
   15076 
   15077     x86-specific (Intel/AMD)
   15078 
   15079      * [283]4823 ICE on inline assembly code
   15080      * [284]8878 miscompilation with -O and SSE
   15081      * [285]9815 (c++ library) atomicity.h - fails to compile with -O3
   15082        -masm=intel
   15083      * [286]10402 (inline assembly) [x86] ICE in merge_assigned_reloads,
   15084        in reload1.c
   15085      * [287]10504 ICE with SSE2 code and -O3 -mcpu=pentium4 -msse2
   15086      * [288]10673 ICE for x86-64 on freebsd libc vfprintf.c source
   15087      * [289]11044 [x86] out of range loop instructions for FP code on K6
   15088      * [290]11089 ICE: instantiate_virtual_regs_lossage while using SSE
   15089        built-ins
   15090      * [291]11420 [x86_64] gcc generates invalid asm code when "-O -fPIC"
   15091        is used
   15092 
   15093     SPARC- or Solaris- specific
   15094 
   15095      * [292]9362 solaris 'as' dies when fed .s and "-gstabs"
   15096      * [293]10142 [SPARC64] gcc produces wrong code when passing
   15097        structures by value
   15098      * [294]10663 New configure check aborts with Sun tools.
   15099      * [295]10835 combinatorial explosion in scheduler on HyperSPARC
   15100      * [296]10876 ICE in calculate_giv_inc when building KDE
   15101      * [297]10955 wrong code at -O3 for structure argument in context of
   15102        structure return
   15103      * [298]11018 -mcpu=ultrasparc busts tar-1.13.25
   15104      * [299]11556 [sparc64] ICE in gen_reg_rtx() while compiling 2.6.x
   15105        Linux kernel
   15106 
   15107     ia64 specific
   15108 
   15109      * [300]10907 gcc violates the ia64 ABI (GP must be preserved)
   15110      * [301]11320 scheduler bug (in machine depended reorganization pass)
   15111      * [302]11599 bug with conditional and __builtin_prefetch
   15112 
   15113     PowerPC specific
   15114 
   15115      * [303]9745 [powerpc] gcc mis-compiles libmcrypt (alias problem
   15116        during loop)
   15117      * [304]10871 error in rs6000_stack_info save_size computation
   15118      * [305]11440 gcc mis-compiles c++ code (libkhtml) with -O2, -fno-gcse
   15119        cures it
   15120 
   15121     m68k-specific
   15122 
   15123      * [306]7594 [m68k] ICE on legal code associated with simplify-rtx
   15124      * [307]10557 [m68k] ICE in subreg_offset_representable_p
   15125      * [308]11054 [m68k] ICE in reg_overlap_mentioned_p
   15126 
   15127     ARM-specific
   15128 
   15129      * [309]10834 [arm] GCC 3.3 still generates incorrect instructions for
   15130        functions with __attribute__ ((interrupt ("IRQ")))
   15131      * [310]10842 [arm] Clobbered link register is copied to pc under
   15132        certain circumstances
   15133      * [311]11052 [arm] noce_process_if_block() can lose REG_INC notes
   15134      * [312]11183 [arm] ICE in change_address_1 (3.3) / subreg_hard_regno
   15135        (3.4)
   15136 
   15137     MIPS-specific
   15138 
   15139      * [313]11084 ICE in propagate_one_insn, in flow.c
   15140 
   15141     SH-specific
   15142 
   15143      * [314]10331 can't compile c++ part of gcc cross compiler for sh-elf
   15144      * [315]10413 [SH] ICE in reload_cse_simplify_operands, in reload1.c
   15145      * [316]11096 i686-linux to sh-linux cross compiler fails to compile
   15146        C++ files
   15147 
   15148     GNU/Linux (or Hurd?) specific
   15149 
   15150      * [317]2873 Bogus fixinclude of stdio.h from glibc 2.2.3
   15151 
   15152     UnixWare specific
   15153 
   15154      * [318]3163 configure bug: gcc/aclocal.m4 mmap test fails on UnixWare
   15155        7.1.1
   15156 
   15157     Cygwin (or mingw) specific
   15158 
   15159      * [319]5287 ICE with dllimport attribute
   15160      * [320]10148 [MingW/CygWin] Compiler dumps core
   15161 
   15162     DJGPP specific
   15163 
   15164      * [321]8787 GCC fails to emit .intel_syntax when invoked with
   15165        -masm=intel on DJGPP
   15166 
   15167     Darwin (and MacOS X) specific
   15168 
   15169      * [322]10900 trampolines crash
   15170 
   15171     Documentation
   15172 
   15173      * [323]1607 (c++) Format attributes on methods undocumented
   15174      * [324]4252 Invalid option `-fdump-translation-unit'
   15175      * [325]4490 Clarify restrictions on -m96bit-long-double,
   15176        -m128bit-long-double
   15177      * [326]10355 document an issue with regparm attribute on some systems
   15178        (e.g. Solaris)
   15179      * [327]10726 (fortran) Documentation for function "IDate Intrinsic
   15180        (Unix)" is wrong
   15181      * [328]10805 document bug in old version of Sun assembler
   15182      * [329]10815 warn against GNU binutils on AIX
   15183      * [330]10877 document need for newer binutils on i?86-*-linux-gnu
   15184      * [331]11280 Manual incorrect with respect to -freorder-blocks
   15185      * [332]11466 Document -mlittle-endian and its restrictions for the
   15186        sparc64 port
   15187 
   15188     Testsuite bugs (compiler itself is not affected)
   15189 
   15190      * [333]10737 newer bison causes g++.dg/parse/crash2.C to incorrectly
   15191        report failure
   15192      * [334]10810 gcc-3.3 fails make check: buffer overrun in
   15193        test_demangle.c
   15194      __________________________________________________________________
   15195 
   15196 GCC 3.3.2
   15197 
   15198   Bug Fixes
   15199 
   15200    This section lists the problem reports (PRs) from GCC's bug tracker
   15201    that are known to be fixed in the 3.3.2 release. This list might not be
   15202    complete (that is, it is possible that some PRs that have been fixed
   15203    are not listed here).
   15204 
   15205     Bootstrap failures and problems
   15206 
   15207      * [335]8336 [SCO5] bootstrap config still tries to use COFF options
   15208      * [336]9330 [alpha-osf] Bootstrap failure on Compaq Tru64 with
   15209        --enable-threads=posix
   15210      * [337]9631 [hppa64-linux] gcc-3.3 fails to bootstrap
   15211      * [338]9877 fixincludes makes a bad sys/byteorder.h on svr5 (UnixWare
   15212        7.1.1)
   15213      * [339]11687 xstormy16-elf build fails in libf2c
   15214      * [340]12263 [SGI IRIX] bootstrap fails during compile of
   15215        libf2c/libI77/backspace.c
   15216      * [341]12490 buffer overflow in scan-decls.c (during Solaris 9
   15217        fix-header processing)
   15218 
   15219     Internal compiler errors (multi-platform)
   15220 
   15221      * [342]7277 Casting integers to vector types causes ICE
   15222      * [343]7939 (c++) ICE on invalid function template specialization
   15223      * [344]11063 (c++) ICE on parsing initialization list of const array
   15224        member
   15225      * [345]11207 ICE with negative index in array element designator
   15226      * [346]11522 (fortran) g77 dwarf-2 ICE in
   15227        add_abstract_origin_attribute
   15228      * [347]11595 (c++) ICE on duplicate label definition
   15229      * [348]11646 (c++) ICE in commit_one_edge_insertion with
   15230        -fnon-call-exceptions -fgcse -O
   15231      * [349]11665 ICE in struct initializer when taking address
   15232      * [350]11852 (c++) ICE with bad struct initializer.
   15233      * [351]11878 (c++) ICE in cp_expr_size
   15234      * [352]11883 ICE with any -O on mercury-generated C code
   15235      * [353]11991 (c++) ICE in cxx_incomplete_type_diagnostic, in
   15236        cp/typeck2.c when applying typeid operator to template template
   15237        parameter
   15238      * [354]12146 ICE in lookup_template_function, in cp/pt.c
   15239      * [355]12215 ICE in make_label_edge with -fnon-call-exceptions
   15240        -fno-gcse -O2
   15241      * [356]12369 (c++) ICE with templates and friends
   15242      * [357]12446 ICE in emit_move_insn on complicated array reference
   15243      * [358]12510 ICE in final_scan_insn
   15244      * [359]12544 ICE with large parameters used in nested functions
   15245 
   15246     C and optimization bugs
   15247 
   15248      * [360]9862 spurious warnings with -W -finline-functions
   15249      * [361]10962 lookup_field is a linear search on a linked list (can be
   15250        slow if large struct)
   15251      * [362]11370 -Wunreachable-code gives false complaints
   15252      * [363]11637 invalid assembly with -fnon-call-exceptions
   15253      * [364]11885 Problem with bitfields in packed structs
   15254      * [365]12082 Inappropriate unreachable code warnings
   15255      * [366]12180 Inline optimization fails for variadic function
   15256      * [367]12340 loop unroller + gcse produces wrong code
   15257 
   15258     C++ compiler and library
   15259 
   15260      * [368]3907 nested template parameter collides with member name
   15261      * [369]5293 confusing message when binding a temporary to a reference
   15262      * [370]5296 [DR115] Pointers to functions and to template functions
   15263        behave differently in deduction
   15264      * [371]7939 ICE on function template specialization
   15265      * [372]8656 Unable to assign function with __attribute__ and pointer
   15266        return type to an appropriate variable
   15267      * [373]10147 Confusing error message for invalid template function
   15268        argument
   15269      * [374]11400 std::search_n() makes assumptions about Size parameter
   15270      * [375]11409 issues with using declarations, overloading, and
   15271        built-in functions
   15272      * [376]11740 ctype<wchar_t>::do_is(mask, wchar_t) doesn't handle
   15273        multiple bits in mask
   15274      * [377]11786 operator() call on variable in other namespace not
   15275        recognized
   15276      * [378]11867 static_cast ignores ambiguity
   15277      * [379]11928 bug with conversion operators that are typedefs
   15278      * [380]12114 Uninitialized memory accessed in dtor
   15279      * [381]12163 static_cast + explicit constructor regression
   15280      * [382]12181 Wrong code with comma operator and c++
   15281      * [383]12236 regparm and fastcall messes up parameters
   15282      * [384]12266 incorrect instantiation of unneeded template during
   15283        overload resolution
   15284      * [385]12296 istream::peek() doesn't set eofbit
   15285      * [386]12298 [sjlj exceptions] Stack unwind destroys
   15286        not-yet-constructed object
   15287      * [387]12369 ICE with templates and friends
   15288      * [388]12337 apparently infinite loop in g++
   15289      * [389]12344 stdcall attribute ignored if function returns a pointer
   15290      * [390]12451 missing(late) class forward declaration in cxxabi.h
   15291      * [391]12486 g++ accepts invalid use of a qualified name
   15292 
   15293     x86 specific (Intel/AMD)
   15294 
   15295      * [392]8869 [x86 MMX] ICE with const variable optimization and MMX
   15296        builtins
   15297      * [393]9786 ICE in fixup_abnormal_edges with -fnon-call-exceptions
   15298        -O2
   15299      * [394]11689 g++3.3 emits un-assembleable code for k6 architecture
   15300      * [395]12116 [k6] Invalid assembly output values with X-MAME code
   15301      * [396]12070 ICE converting between double and long double with
   15302        -msoft-float
   15303 
   15304     ia64-specific
   15305 
   15306      * [397]11184 [ia64 hpux] ICE on __builtin_apply building libobjc
   15307      * [398]11535 __builtin_return_address may not work on ia64
   15308      * [399]11693 [ia64] ICE in gen_nop_type
   15309      * [400]12224 [ia64] Thread-local storage doesn't work
   15310 
   15311     PowerPC-specific
   15312 
   15313      * [401]11087 [powerpc64-linux] GCC miscompiles raid1.c from linux
   15314        kernel
   15315      * [402]11319 loop miscompiled on ppc32
   15316      * [403]11949 ICE Compiler segfault with ffmpeg -maltivec code
   15317 
   15318     SPARC-specific
   15319 
   15320      * [404]11662 wrong code for expr. with cast to long long and
   15321        exclusive or
   15322      * [405]11965 invalid assembler code for a shift < 32 operation
   15323      * [406]12301 (c++) stack corruption when a returned expression throws
   15324        an exception
   15325 
   15326     Alpha-specific
   15327 
   15328      * [407]11717 [alpha-linux] unrecognizable insn compiling for.c of
   15329        kernel 2.4.22-pre8
   15330 
   15331     HPUX-specific
   15332 
   15333      * [408]11313 problem with #pragma weak and static inline functions
   15334      * [409]11712 __STDC_EXT__ not defined for C++ by default anymore?
   15335 
   15336     Solaris specific
   15337 
   15338      * [410]12166 Profiled programs crash if PROFDIR is set
   15339 
   15340     Solaris-x86 specific
   15341 
   15342      * [411]12101 i386 Solaris no longer works with GNU as?
   15343 
   15344     Miscellaneous embedded target-specific bugs
   15345 
   15346      * [412]10988 [m32r-elf] wrong blockmove code with -O3
   15347      * [413]11805 [h8300-unknown-coff] [H8300] ICE for simple code with
   15348        -O2
   15349      * [414]11902 [sh4] spec file improperly inserts rpath even when none
   15350        needed
   15351      * [415]11903 [sh4] -pthread fails to link due to error in spec file
   15352        on sh4
   15353      __________________________________________________________________
   15354 
   15355 GCC 3.3.3
   15356 
   15357   Minor features
   15358 
   15359    In addition to the bug fixes documented below, this release contains
   15360    few minor features such as:
   15361      * Support for --with-sysroot
   15362      * Support for automatic detection of executable stacks
   15363      * Support for SSE3 instructions
   15364      * Support for thread local storage debugging under GDB on S390
   15365 
   15366   Bug Fixes
   15367 
   15368    This section lists the problem reports (PRs) from GCC's bug tracker
   15369    that are known to be fixed in the 3.3.3 release. This list might not be
   15370    complete (that is, it is possible that some PRs that have been fixed
   15371    are not listed here).
   15372 
   15373     Bootstrap failures and issues
   15374 
   15375      * [416]11890 Building cross gcc-3.3.1 for sparc-sun-solaris2.6 fails
   15376      * [417]12399 boehm-gc fails (when building a cross compiler): libtool
   15377        unable to infer tagged configuration
   15378      * [418]13068 mklibgcc.in doesn't handle multi-level multilib
   15379        subdirectories properly
   15380 
   15381     Internal compiler errors (multi-platform)
   15382 
   15383      * [419]10060 ICE (stack overflow) on huge file (300k lines) due to
   15384        recursive behaviour of copy_rtx_if_shared, in emit_rtl.c
   15385      * [420]10555 (c++) ICE on undefined template argument
   15386      * [421]10706 (c++) ICE in mangle_class_name_for_template
   15387      * [422]11496 (fortran) error in flow_loops_find when -funroll-loops
   15388        active
   15389      * [423]11741 ICE in pre_insert_copy_insn, in gcse.c
   15390      * [424]12440 GCC crashes during compilation of quicktime4linux 2.0.0
   15391      * [425]12632 (fortran) -fbounds-check ICE
   15392      * [426]12712 (c++) ICE on short legit C++ code fragment with gcc
   15393        3.3.2
   15394      * [427]12726 (c++) ICE (segfault) on trivial code
   15395      * [428]12890 (c++) ICE on compilation of class with throwing method
   15396      * [429]12900 (c++) ICE in rtl_verify_flow_info_1
   15397      * [430]13060 (fortran) ICE in fixup_var_refs_1, in function.c on
   15398        correct code with -O2 -fno-force-mem
   15399      * [431]13289 (c++) ICE in regenerate_decl_from_template on recursive
   15400        template
   15401      * [432]13318 ICE: floating point exception in the loop optimizer
   15402      * [433]13392 (c++) ICE in convert_from_eh_region_ranges_1, in
   15403        except.c
   15404      * [434]13574 (c++) invalid array default initializer in class lets
   15405        gcc consume all memory and die
   15406      * [435]13475 ICE on SIMD variables with partial value initialization
   15407      * [436]13797 (c++) ICE on invalid template parameter
   15408      * [437]13824 (java) gcj SEGV with simple .java program
   15409 
   15410     C and optimization bugs
   15411 
   15412      * [438]8776 loop invariants are not removed (most likely)
   15413      * [439]10339 [sparc,ppc,ppc64] Invalid optimization: replacing
   15414        strncmp by memcmp
   15415      * [440]11350 undefined labels with -Os -fPIC
   15416      * [441]12826 Optimizer removes reference through volatile pointer
   15417      * [442]12500 stabs debug info: void no longer a predefined / builtin
   15418        type
   15419      * [443]12941 builtin-bitops-1.c miscompilation (latent bug)
   15420      * [444]12953 tree inliner bug (in inline_forbidden_p) and fix
   15421      * [445]13041 linux-2.6/sound/core/oss/rate.c miscompiled
   15422      * [446]13507 spurious printf format warning
   15423      * [447]13382 Type information for const pointer disappears during
   15424        optimization.
   15425      * [448]13394 noreturn attribute ignored on recursive invokation
   15426      * [449]13400 Compiled code crashes storing to read-only location
   15427      * [450]13521 Endless loop in calculate_global_regs_live
   15428 
   15429     C++ compiler and library
   15430 
   15431    Some of the bug fixes in this list were made to implement decisions
   15432    that the ISO C++ standards committee has made concerning several defect
   15433    reports (DRs). Links in the list below point to detailed discussion of
   15434    the relevant defect report.
   15435      * [451]2094 unimplemented: use of `ptrmem_cst' in template type
   15436        unification
   15437      * [452]2294 using declaration confusion
   15438      * [453]5050 template instantiation depth exceeds limit: recursion
   15439        problem?
   15440      * [454]9371 Bad exception handling in
   15441        i/ostream::operator>>/<<(streambuf*)
   15442      * [455]9546 bad exception handling in ostream members
   15443      * [456]10081 basic_ios::_M_cache_locale leaves NULL members in the
   15444        face of unknown locales
   15445      * [457]10093 [458][DR 61] Setting failbit in exceptions doesn't work
   15446      * [459]10095 istream::operator>>(int&) sets ios::badbit when
   15447        ios::failbit is set.
   15448      * [460]11554 Warning about reordering of initializers doesn't mention
   15449        location of constructor
   15450      * [461]12297 istream::sentry::sentry() handles eof() incorrectly.
   15451      * [462]12352 Exception safety problems in src/localename.cc
   15452      * [463]12438 Memory leak in locale::combine()
   15453      * [464]12540 Memory leak in locale::locale(const char*)
   15454      * [465]12594 DRs [466]60 [TC] and [467]63 [TC] not implemented
   15455      * [468]12657 Resolution of [469]DR 292 (WP) still unimplemented
   15456      * [470]12696 memory eating infinite loop in diagnostics (error
   15457        recovery problem)
   15458      * [471]12815 Code compiled with optimization behaves unexpectedly
   15459      * [472]12862 Conflicts between typedefs/enums and namespace member
   15460        declarations
   15461      * [473]12926 Wrong value after assignment in initialize list using
   15462        bit-fields
   15463      * [474]12967 Resolution of [475]DR 300 [WP] still unimplemented
   15464      * [476]12971 Resolution of [477]DR 328 [WP] still unimplemented
   15465      * [478]13007 basic_streambuf::pubimbue, imbue wrong
   15466      * [479]13009 Implicitly-defined assignment operator writes to wrong
   15467        memory
   15468      * [480]13057 regparm attribute not applied to destructor
   15469      * [481]13070 -Wformat option ignored in g++
   15470      * [482]13081 forward template declarations in <complex> let inlining
   15471        fail
   15472      * [483]13239 Assertion does not seem to work correctly anymore
   15473      * [484]13262 "xxx is private within this context" when initializing a
   15474        self-contained template class
   15475      * [485]13290 simple typo in concept checking for std::generate_n
   15476      * [486]13323 Template code does not compile in presence of typedef
   15477      * [487]13369 __verify_grouping (and __add_grouping?) not correct
   15478      * [488]13371 infinite loop with packed struct and inlining
   15479      * [489]13445 Template argument replacement "dereferences" a typedef
   15480      * [490]13461 Fails to access protected-ctor from public constant
   15481      * [491]13462 Non-standard-conforming type set::pointer
   15482      * [492]13478 gcc uses wrong constructor to initialize a const
   15483        reference
   15484      * [493]13544 "conflicting types" for enums in different scopes
   15485      * [494]13650 string::compare should not (always) use
   15486        traits_type::length()
   15487      * [495]13683 bogus warning about passing non-PODs through ellipsis
   15488      * [496]13688 Derived class is denied access to protected base class
   15489        member class
   15490      * [497]13774 Member variable cleared in virtual multiple inheritance
   15491        class
   15492      * [498]13884 Protect sstream.tcc from extern template use
   15493 
   15494     Java compiler and library
   15495 
   15496      * [499]10746 [win32] garbage collection crash in GCJ
   15497 
   15498     Objective-C compiler and library
   15499 
   15500      * [500]11433 Crash due to dereferencing null pointer when querying
   15501        protocol
   15502 
   15503     Fortran compiler and library
   15504 
   15505      * [501]12633 logical expression gives incorrect result with
   15506        -fugly-logint option
   15507      * [502]13037 [gcse-lm] g77 generates incorrect code
   15508      * [503]13213 Hex constant problem when compiling with -fugly-logint
   15509        and -ftypeless-boz
   15510 
   15511     x86-specific (Intel/AMD)
   15512 
   15513      * [504]4490 ICE with -m128bit-long-double
   15514      * [505]12292 [x86_64] ICE: RTL check: expected code `const_int', have
   15515        `reg' in make_field_assignment, in combine.c
   15516      * [506]12441 ICE: can't find a register to spill
   15517      * [507]12943 array static-init failure under -fpic, -fPIC
   15518      * [508]13608 Incorrect code with -O3 -ffast-math
   15519 
   15520     PowerPC-specific
   15521 
   15522      * [509]11598 testcase gcc.dg/20020118-1.c fails runtime check of
   15523        __attribute__((aligned(16)))
   15524      * [510]11793 ICE in extract_insn, in recog.c (const_vector's)
   15525      * [511]12467 vmsumubm emitted when vmsummbm appropriate (typo in
   15526        altivec.md)
   15527      * [512]12537 g++ generates writeable text sections
   15528 
   15529     SPARC-specific
   15530 
   15531      * [513]12496 wrong result for __atomic_add(&value, -1) when using -O0
   15532        -m64
   15533      * [514]12865 mprotect call to make trampoline executable may fail
   15534      * [515]13354 ICE in sparc_emit_set_const32
   15535 
   15536     ARM-specific
   15537 
   15538      * [516]10467 [arm] ICE in pre_insert_copy_insn,
   15539 
   15540     ia64-specific
   15541 
   15542      * [517]11226 ICE passing struct arg with two floats
   15543      * [518]11227 ICE for _Complex float, _Complex long double args
   15544      * [519]12644 GCC 3.3.2 fails to compile glibc on ia64
   15545      * [520]13149 build gcc-3.3.2 1305 error:unrecognizable insn
   15546      * Various fixes for libunwind
   15547 
   15548     Alpha-specific
   15549 
   15550      * [521]12654 Incorrect comparison code generated for Alpha
   15551      * [522]12965 SEGV+ICE in cc1plus on alpha-linux with -O2
   15552      * [523]13031 ICE (unrecognizable insn) when building gnome-libs-1.4.2
   15553 
   15554     HPPA-specific
   15555 
   15556      * [524]11634 [hppa] ICE in verify_local_live_at_start, in flow.c
   15557      * [525]12158 [hppa] compilation does not terminate at -O1
   15558 
   15559     S390-specific
   15560 
   15561      * [526]11992 Wrong built-in code for memcmp with length 1<<24: only
   15562        (1<<24)-1 possible for CLCL-Instruction
   15563 
   15564     SH-specific
   15565 
   15566      * [527]9365 segfault in gen_far_branch (config/sh/sh.c)
   15567      * [528]10392 optimizer generates faulty array indexing
   15568      * [529]11322 SH profiler outputs multiple definitions of symbol
   15569      * [530]13069 gcc/config/sh/rtems.h broken
   15570      * [531]13302 Putting a va_list in a struct causes seg fault
   15571      * [532]13585 Incorrect optimization of call to sfunc
   15572      * Fix inappropriately exported libgcc functions from the shared
   15573        library
   15574 
   15575     Other embedded target specific
   15576 
   15577      * [533]8916 [mcore] unsigned char assign gets hosed.
   15578      * [534]11576 [h8300] ICE in change_address_1, in emit-rtl.c
   15579      * [535]13122 [h8300] local variable gets corrupted by function call
   15580        when -fomit-frame-pointer is given
   15581      * [536]13256 [cris] strict_low_part mistreated in delay slots
   15582      * [537]13373 [mcore] optimization with -frerun-cse-after-loop
   15583        -fexpensive-optimizations produces wrong code on mcore
   15584 
   15585     GNU HURD-specific
   15586 
   15587      * [538]12561 gcc/config/t-gnu needs updating to work with
   15588        --with-sysroot
   15589 
   15590     Tru64 Unix specific
   15591 
   15592      * [539]6243 testsuite fails almost all tests due to no libintl in
   15593        LD_LIBRARY_PATH during test.
   15594      * [540]11397 weak aliases broken on Tru64 UNIX
   15595 
   15596     AIX-specific
   15597 
   15598      * [541]12505 build failure due to defines of uchar in cpphash.h and
   15599        sys/types.h
   15600      * [542]13150 WEAK symbols not exported by collect2
   15601 
   15602     IRIX-specific
   15603 
   15604      * [543]12666 fixincludes problem on IRIX 6.5.19m
   15605 
   15606     Solaris-specific
   15607 
   15608      * [544]12969 Including sys/byteorder.h breaks configure checks
   15609 
   15610     Testsuite problems (compiler is not affected)
   15611 
   15612      * [545]10819 testsuite creates CR+LF on compiler version lines in
   15613        test summary files
   15614      * [546]11612 abi_check not finding correct libgcc_s.so.1
   15615 
   15616     Miscellaneous
   15617 
   15618      * [547]13211 using -###, incorrect warnings about unused linker file
   15619        are produced
   15620      __________________________________________________________________
   15621 
   15622 GCC 3.3.4
   15623 
   15624    This is the [548]list of problem reports (PRs) from GCC's bug tracking
   15625    system that are known to be fixed in the 3.3.4 release. This list might
   15626    not be complete (that is, it is possible that some PRs that have been
   15627    fixed are not listed here).
   15628      __________________________________________________________________
   15629 
   15630 GCC 3.3.5
   15631 
   15632    This is the [549]list of problem reports (PRs) from GCC's bug tracking
   15633    system that are known to be fixed in the 3.3.5 release. This list might
   15634    not be complete (that is, it is possible that some PRs that have been
   15635    fixed are not listed here).
   15636      __________________________________________________________________
   15637 
   15638 GCC 3.3.6
   15639 
   15640    This is the [550]list of problem reports (PRs) from GCC's bug tracking
   15641    system that are known to be fixed in the 3.3.6 release. This list might
   15642    not be complete (that is, it is possible that some PRs that have been
   15643    fixed are not listed here).
   15644 
   15645 
   15646     For questions related to the use of GCC, please consult these web
   15647     pages and the [551]GCC manuals. If that fails, the
   15648     [552]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   15649     web pages and the development of GCC are welcome on our developer
   15650     list at [553]gcc (a] gcc.gnu.org. All of [554]our lists have public
   15651     archives.
   15652 
   15653    Copyright (C) [555]Free Software Foundation, Inc. Verbatim copying and
   15654    distribution of this entire article is permitted in any medium,
   15655    provided this notice is preserved.
   15656 
   15657    These pages are [556]maintained by the GCC team. Last modified
   15658    2019-11-28[557].
   15659 
   15660 References
   15661 
   15662    1. http://gcc.gnu.org/gcc-3.3/changes.html#3.3.6
   15663    2. http://gcc.gnu.org/gcc-3.1/changes.html#obsolete_systems
   15664    3. http://gcc.gnu.org/gcc-3.3/changes.html#obsolete_systems
   15665    4. http://gcc.gnu.org/gcc-3.3/changes.html#nonnull_attribute
   15666    5. http://gcc.gnu.org/news/dfa.html
   15667    6. http://gcc.gnu.org/c99status.html
   15668    7. https://gcc.gnu.org/onlinedocs/gcc-3.3.6/g77/News.html
   15669    8. https://gcc.gnu.org/PR10140
   15670    9. https://gcc.gnu.org/PR10198
   15671   10. https://gcc.gnu.org/PR10338
   15672   11. https://gcc.gnu.org/PR3581
   15673   12. https://gcc.gnu.org/PR4382
   15674   13. https://gcc.gnu.org/PR5533
   15675   14. https://gcc.gnu.org/PR6387
   15676   15. https://gcc.gnu.org/PR6412
   15677   16. https://gcc.gnu.org/PR6620
   15678   17. https://gcc.gnu.org/PR6663
   15679   18. https://gcc.gnu.org/PR7068
   15680   19. https://gcc.gnu.org/PR7083
   15681   20. https://gcc.gnu.org/PR7647
   15682   21. https://gcc.gnu.org/PR7675
   15683   22. https://gcc.gnu.org/PR7718
   15684   23. https://gcc.gnu.org/PR8116
   15685   24. https://gcc.gnu.org/PR8358
   15686   25. https://gcc.gnu.org/PR8511
   15687   26. https://gcc.gnu.org/PR8564
   15688   27. https://gcc.gnu.org/PR8660
   15689   28. https://gcc.gnu.org/PR8766
   15690   29. https://gcc.gnu.org/PR8803
   15691   30. https://gcc.gnu.org/PR8846
   15692   31. https://gcc.gnu.org/PR8906
   15693   32. https://gcc.gnu.org/PR9216
   15694   33. https://gcc.gnu.org/PR9261
   15695   34. https://gcc.gnu.org/PR9263
   15696   35. https://gcc.gnu.org/PR9429
   15697   36. https://gcc.gnu.org/PR9516
   15698   37. https://gcc.gnu.org/PR9600
   15699   38. https://gcc.gnu.org/PR9629
   15700   39. https://gcc.gnu.org/PR9672
   15701   40. https://gcc.gnu.org/PR9749
   15702   41. https://gcc.gnu.org/PR9794
   15703   42. https://gcc.gnu.org/PR9829
   15704   43. https://gcc.gnu.org/PR9916
   15705   44. https://gcc.gnu.org/PR9936
   15706   45. https://gcc.gnu.org/PR10262
   15707   46. https://gcc.gnu.org/PR10278
   15708   47. https://gcc.gnu.org/PR10446
   15709   48. https://gcc.gnu.org/PR10451
   15710   49. https://gcc.gnu.org/PR10506
   15711   50. https://gcc.gnu.org/PR10549
   15712   51. https://gcc.gnu.org/PR2001
   15713   52. https://gcc.gnu.org/PR2391
   15714   53. https://gcc.gnu.org/PR2960
   15715   54. https://gcc.gnu.org/PR4046
   15716   55. https://gcc.gnu.org/PR6405
   15717   56. https://gcc.gnu.org/PR6798
   15718   57. https://gcc.gnu.org/PR6871
   15719   58. https://gcc.gnu.org/PR6909
   15720   59. https://gcc.gnu.org/PR7189
   15721   60. https://gcc.gnu.org/PR7642
   15722   61. https://gcc.gnu.org/PR8634
   15723   62. https://gcc.gnu.org/PR8750
   15724   63. https://gcc.gnu.org/PR2161
   15725   64. https://gcc.gnu.org/PR4319
   15726   65. https://gcc.gnu.org/PR8602
   15727   66. https://gcc.gnu.org/PR9177
   15728   67. https://gcc.gnu.org/PR9853
   15729   68. https://gcc.gnu.org/PR45
   15730   69. https://gcc.gnu.org/PR3784
   15731   70. https://gcc.gnu.org/PR764
   15732   71. https://gcc.gnu.org/PR5116
   15733   72. https://gcc.gnu.org/PR2862
   15734   73. https://gcc.gnu.org/PR3663
   15735   74. https://gcc.gnu.org/PR3797
   15736   75. https://gcc.gnu.org/PR3948
   15737   76. https://gcc.gnu.org/PR4137
   15738   77. https://gcc.gnu.org/PR4361
   15739   78. https://gcc.gnu.org/PR4802
   15740   79. https://gcc.gnu.org/PR5837
   15741   80. https://gcc.gnu.org/PR4803
   15742   81. https://gcc.gnu.org/PR5094
   15743   82. https://gcc.gnu.org/PR5730
   15744   83. https://gcc.gnu.org/PR6713
   15745   84. https://gcc.gnu.org/PR7015
   15746   85. https://gcc.gnu.org/PR7086
   15747   86. https://gcc.gnu.org/PR7099
   15748   87. https://gcc.gnu.org/PR7247
   15749   88. https://gcc.gnu.org/PR7441
   15750   89. https://gcc.gnu.org/PR7768
   15751   90. https://gcc.gnu.org/PR7804
   15752   91. https://gcc.gnu.org/PR8099
   15753   92. https://gcc.gnu.org/PR8117
   15754   93. https://gcc.gnu.org/PR8205
   15755   94. https://gcc.gnu.org/PR8645
   15756   95. https://gcc.gnu.org/PR8724
   15757   96. https://gcc.gnu.org/PR8805
   15758   97. https://gcc.gnu.org/PR8691
   15759   98. https://gcc.gnu.org/PR8700
   15760   99. https://gcc.gnu.org/PR8724
   15761  100. https://gcc.gnu.org/PR8949
   15762  101. https://gcc.gnu.org/PR9016
   15763  102. https://gcc.gnu.org/PR9053
   15764  103. https://gcc.gnu.org/PR9152
   15765  104. https://gcc.gnu.org/PR9182
   15766  105. https://gcc.gnu.org/PR9297
   15767  106. https://gcc.gnu.org/PR9318
   15768  107. https://gcc.gnu.org/PR9320
   15769  108. https://gcc.gnu.org/PR9400
   15770  109. https://gcc.gnu.org/PR9424
   15771  110. https://gcc.gnu.org/PR9425
   15772  111. https://gcc.gnu.org/PR9439
   15773  112. https://gcc.gnu.org/PR9474
   15774  113. https://gcc.gnu.org/PR9548
   15775  114. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#231
   15776  115. https://gcc.gnu.org/PR9555
   15777  116. https://gcc.gnu.org/PR9561
   15778  117. https://gcc.gnu.org/PR9563
   15779  118. https://gcc.gnu.org/PR9582
   15780  119. https://gcc.gnu.org/PR9622
   15781  120. https://gcc.gnu.org/PR9683
   15782  121. https://gcc.gnu.org/PR9791
   15783  122. https://gcc.gnu.org/PR9817
   15784  123. https://gcc.gnu.org/PR9825
   15785  124. https://gcc.gnu.org/PR9826
   15786  125. https://gcc.gnu.org/PR9924
   15787  126. https://gcc.gnu.org/PR9946
   15788  127. https://gcc.gnu.org/PR9964
   15789  128. https://gcc.gnu.org/PR9988
   15790  129. https://gcc.gnu.org/PR10033
   15791  130. https://gcc.gnu.org/PR10097
   15792  131. https://gcc.gnu.org/PR10132
   15793  132. https://gcc.gnu.org/PR10180
   15794  133. https://gcc.gnu.org/PR10199
   15795  134. https://gcc.gnu.org/PR10300
   15796  135. https://gcc.gnu.org/PR10427
   15797  136. https://gcc.gnu.org/PR10503
   15798  137. https://gcc.gnu.org/PR5956
   15799  138. https://gcc.gnu.org/PR1832
   15800  139. https://gcc.gnu.org/PR3924
   15801  140. https://gcc.gnu.org/PR5634
   15802  141. https://gcc.gnu.org/PR6367
   15803  142. https://gcc.gnu.org/PR6491
   15804  143. https://gcc.gnu.org/PR6742
   15805  144. https://gcc.gnu.org/PR7113
   15806  145. https://gcc.gnu.org/PR7236
   15807  146. https://gcc.gnu.org/PR7278
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   16207  546. https://gcc.gnu.org/PR11612
   16208  547. https://gcc.gnu.org/PR13211
   16209  548. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.4
   16210  549. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.5
   16211  550. https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=3.3.6
   16212  551. https://gcc.gnu.org/onlinedocs/
   16213  552. mailto:gcc-help (a] gcc.gnu.org
   16214  553. mailto:gcc (a] gcc.gnu.org
   16215  554. https://gcc.gnu.org/lists.html
   16216  555. https://www.fsf.org/
   16217  556. https://gcc.gnu.org/about.html
   16218  557. http://validator.w3.org/check/referer
   16219 ======================================================================
   16220 http://gcc.gnu.org/gcc-3.2/index.html
   16221                              GCC 3.2 Release Series
   16222 
   16223    (This release series is no longer supported.)
   16224 
   16225    April 25, 2003
   16226 
   16227    The [1]GNU project and the GCC developers are pleased to announce the
   16228    release of GCC 3.2.3.
   16229 
   16230    The purpose of the GCC 3.2 release series is to provide a stable
   16231    platform for OS distributors to use building their next releases. A
   16232    primary objective was to stabilize the C++ ABI; we believe that the
   16233    interface to the compiler and the C++ standard library are now
   16234    relatively stable.
   16235 
   16236    Be aware that C++ code compiled by GCC 3.2.x will (in general) not
   16237    interoperate with code compiled by GCC 3.1.1 or earlier.
   16238 
   16239    Please refer to our [2]detailed list of news, caveats, and bug-fixes
   16240    for further information.
   16241 
   16242 Release History
   16243 
   16244    GCC 3.2.3
   16245           April 25, 2003 ([3]changes)
   16246 
   16247    GCC 3.2.2
   16248           February 5, 2003 ([4]changes)
   16249 
   16250    GCC 3.2.1
   16251           November 19, 2002 ([5]changes)
   16252 
   16253    GCC 3.2
   16254           August 14, 2002 ([6]changes)
   16255 
   16256 References and Acknowledgements
   16257 
   16258    GCC used to stand for the GNU C Compiler, but since the compiler
   16259    supports several other languages aside from C, it now stands for the
   16260    GNU Compiler Collection.
   16261 
   16262    A list of [7]successful builds is updated as new information becomes
   16263    available.
   16264 
   16265    The GCC developers would like to thank the numerous people that have
   16266    contributed new features, improvements, bug fixes, and other changes as
   16267    well as test results to GCC. This [8]amazing group of volunteers is
   16268    what makes GCC successful.
   16269 
   16270    For additional information about GCC please refer to the [9]GCC project
   16271    web site or contact the [10]GCC development mailing list.
   16272 
   16273    To obtain GCC please use [11]our mirror sites, or our CVS server.
   16274 
   16275 
   16276     For questions related to the use of GCC, please consult these web
   16277     pages and the [12]GCC manuals. If that fails, the
   16278     [13]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   16279     web pages and the development of GCC are welcome on our developer
   16280     list at [14]gcc (a] gcc.gnu.org. All of [15]our lists have public
   16281     archives.
   16282 
   16283    Copyright (C) [16]Free Software Foundation, Inc. Verbatim copying and
   16284    distribution of this entire article is permitted in any medium,
   16285    provided this notice is preserved.
   16286 
   16287    These pages are [17]maintained by the GCC team. Last modified
   16288    2019-11-28[18].
   16289 
   16290 References
   16291 
   16292    1. http://www.gnu.org/
   16293    2. http://gcc.gnu.org/gcc-3.2/changes.html
   16294    3. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3
   16295    4. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.2
   16296    5. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.1
   16297    6. http://gcc.gnu.org/gcc-3.2/changes.html#3.2
   16298    7. http://gcc.gnu.org/gcc-3.2/buildstat.html
   16299    8. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   16300    9. http://gcc.gnu.org/index.html
   16301   10. mailto:gcc (a] gcc.gnu.org
   16302   11. http://gcc.gnu.org/mirrors.html
   16303   12. https://gcc.gnu.org/onlinedocs/
   16304   13. mailto:gcc-help (a] gcc.gnu.org
   16305   14. mailto:gcc (a] gcc.gnu.org
   16306   15. https://gcc.gnu.org/lists.html
   16307   16. https://www.fsf.org/
   16308   17. https://gcc.gnu.org/about.html
   16309   18. http://validator.w3.org/check/referer
   16310 ======================================================================
   16311 http://gcc.gnu.org/gcc-3.2/changes.html
   16312                              GCC 3.2 Release Series
   16313                         Changes, New Features, and Fixes
   16314 
   16315    The latest release in the 3.2 release series is [1]GCC 3.2.3.
   16316 
   16317 Caveats and New Features
   16318 
   16319   Caveats
   16320 
   16321      * The C++ compiler does not correctly zero-initialize
   16322        pointers-to-data members. You must explicitly initialize them. For
   16323        example: int S::*m(0); will work, but depending on
   16324        default-initialization to zero will not work. This bug cannot be
   16325        fixed in GCC 3.2 without inducing unacceptable risks. It will be
   16326        fixed in GCC 3.3.
   16327      * This GCC release is based on the GCC 3.1 sourcebase, and thus has
   16328        all the [2]changes in the GCC 3.1 series. In addition, GCC 3.2 has
   16329        a number of C++ ABI fixes which make its C++ compiler generate
   16330        binary code which is incompatible with the C++ compilers found in
   16331        earlier GCC releases, including GCC 3.1 and GCC 3.1.1.
   16332 
   16333   Frontend Enhancements
   16334 
   16335     C/C++/Objective-C
   16336 
   16337      * The method of constructing the list of directories to be searched
   16338        for header files has been revised. If a directory named by a -I
   16339        option is a standard system include directory, the option is
   16340        ignored to ensure that the default search order for system
   16341        directories and the special treatment of system header files are
   16342        not defeated.
   16343      * The C and Objective-C compilers no longer accept the "Naming Types"
   16344        extension (typedef foo = bar); it was already unavailable in C++.
   16345        Code which uses it will need to be changed to use the "typeof"
   16346        extension instead: typedef typeof(bar) foo. (We have removed this
   16347        extension without a period of deprecation because it has caused the
   16348        compiler to crash since version 3.0 and no one noticed until very
   16349        recently. Thus we conclude it is not in widespread use.)
   16350 
   16351     C++
   16352 
   16353      * GCC 3.2 fixed serveral differences between the C++ ABI implemented
   16354        in GCC and the multi-vendor standard, but more have been found
   16355        since the release. 3.2.1 adds a new warning, -Wabi, to warn about
   16356        code which is affected by these bugs. We will fix these bugs in
   16357        some future release, once we are confident that all have been
   16358        found; until then, it is our intention to make changes to the ABI
   16359        only if they are necessary for correct compilation of C++, as
   16360        opposed to conformance to the ABI documents.
   16361      * For details on how to build an ABI compliant compiler for GNU/Linux
   16362        systems, check the [3]common C++ ABI page.
   16363 
   16364   New Targets and Target Specific Improvements
   16365 
   16366     IA-32
   16367 
   16368      * Fixed a number of bugs in SSE and MMX intrinsics.
   16369      * Fixed common compiler crashes with SSE instruction set enabled
   16370        (implied by -march=pentium3, pentium4, athlon-xp)
   16371      * __m128 and __m128i is not 128bit aligned when used in structures.
   16372 
   16373     x86-64
   16374 
   16375      * A bug whereby the compiler could generate bad code for bzero has
   16376        been fixed.
   16377      * ABI fixes (implying ABI incompatibilities with previous version in
   16378        some corner cases)
   16379      * Fixed prefetch code generation
   16380      __________________________________________________________________
   16381 
   16382 GCC 3.2.3
   16383 
   16384    3.2.3 is a bug fix release only; there are no new features that were
   16385    not present in GCC 3.2.2.
   16386 
   16387   Bug Fixes
   16388 
   16389    This section lists the problem reports (PRs) from GCC's bug tracking
   16390    system that are known to be fixed in the 3.2.3 release. This list might
   16391    not be complete (that is, it is possible that some PRs that have been
   16392    fixed are not listed here), and some of the titles have been changed to
   16393    make them more clear.
   16394 
   16395     Internal Compiler Errors (multi-platform)
   16396 
   16397      * [4]3782: (c++) -quiet -fstats produces a segmentation fault in
   16398        cc1plus
   16399      * [5]6440: (c++) template specializations cause ICE
   16400      * [6]7050: (c++) ICE on: (i ? get_string() : throw)
   16401      * [7]7741: ICE on conflicting types (make_decl_rtl in varasm.c)
   16402      * [8]7982: (c++) ICE due to infinite recursion (using STL set)
   16403      * [9]8068: exceedingly high (infinite) memory usage
   16404      * [10]8178: ICE with __builtin_ffs
   16405      * [11]8396: ICE in copy_to_mode_reg, in explow.c
   16406      * [12]8674: (c++) ICE in cp_expr_size, in cp/cp-lang.c
   16407      * [13]9768: ICE when optimizing inline code at -O2
   16408      * [14]9798: (c++) Infinite recursion (segfault) in
   16409        cp/decl.c:push_using_directive with recursive using directives
   16410      * [15]9799: mismatching structure initializer with nested flexible
   16411        array member: ICE
   16412      * [16]9928: ICE on duplicate enum declaration
   16413      * [17]10114: ICE in mem_loc_descriptor, in dwarf2out.c (affects
   16414        sparc, alpha)
   16415      * [18]10352: ICE in find_reloads_toplev
   16416      * [19]10336: ICE with -Wunreachable-code
   16417 
   16418     C/optimizer bugs:
   16419 
   16420      * [20]8224: Incorrect joining of signed and unsigned division
   16421      * [21]8613: -O2 produces wrong code with builtin strlen and
   16422        postincrements
   16423      * [22]8828: gcc reports some code is unreachable when it is not
   16424      * [23]9226: GCSE breaking argument passing
   16425      * [24]9853: miscompilation of non-constant structure initializer
   16426      * [25]9797: C99-style struct initializers are miscompiled
   16427      * [26]9967: Some standard C function calls should not be replaced
   16428        when optimizing for size
   16429      * [27]10116: ce2: invalid merge of join_bb in the context of switch
   16430        statements
   16431      * [28]10171: wrong code for inlined function
   16432      * [29]10175: -Wunreachable-code doesn't work for single lines
   16433 
   16434     C++ compiler and library:
   16435 
   16436      * [30]8316: Confusing diagnostic for code that misuses conversion
   16437        operators
   16438      * [31]9169: filebuf output fails if codecvt<>::out returns noconv
   16439      * [32]9420: incomplete type incorrectly reported
   16440      * [33]9459: typeof in return type specification of template not
   16441        supported
   16442      * [34]9507: filebuf::open handles ios_base::ate incorrectly
   16443      * [35]9538: Out-of-bounds memory access in streambuf::sputbackc
   16444      * [36]9602: Total confusion about template/friend/virtual/abstract
   16445      * [37]9993: destructor not called for local object created within and
   16446        returned from infinite loop
   16447      * [38]10167: ieee_1003.1-2001 locale specialisations on a glibc-2.3.2
   16448        system
   16449 
   16450     Java compiler and library:
   16451 
   16452      * [39]9652: libgcj build fails on irix6.5.1[78]
   16453      * [40]10144: gas on solaris complains about bad .stabs lines for
   16454        java, native as unaffected
   16455 
   16456     x86-specific (Intel/AMD):
   16457 
   16458      * [41]8746: gcc miscompiles Linux kernel ppa driver on x86
   16459      * [42]9888: -mcpu=k6 -Os produces out of range loop instructions
   16460      * [43]9638: Cross-build for target i386-elf and i586-pc-linux-gnu
   16461        failed
   16462      * [44]9954: Cross-build for target i586-pc-linux-gnu (--with-newlib)
   16463        failed
   16464 
   16465     SPARC-specific:
   16466 
   16467      * [45]7784: [Sparc] ICE in extract_insn, in recog.c
   16468      * [46]7796: sparc extra failure with -m64 on execute/930921-1.c in
   16469        unroll.c
   16470      * [47]8281: ICE when compiling with -O2 -fPIC for Ultrasparc
   16471      * [48]8366: [Sparc] C testsuite failure with -m64 -fpic -O in
   16472        execute/loop-2d.c
   16473      * [49]8726: gcc -O2 miscompiles Samba 2.2.7 on 32-bit sparc
   16474      * [50]9414: Scheduling bug on Ultrasparc
   16475      * [51]10067: GCC-3.2.2 outputs invalid asm on sparc64
   16476 
   16477     m68k-specific:
   16478 
   16479      * [52]7248: broken "inclusive or" code
   16480      * [53]8343: m68k-elf/rtems ICE at instantiate_virtual_regs_1
   16481 
   16482     PowerPC-specific:
   16483 
   16484      * [54]9732: Wrong code with -O2 -fPIC
   16485      * [55]10073: ICE: powerpc cannot split insn
   16486 
   16487     Alpha-specific:
   16488 
   16489      * [56]7702: optimization problem on a DEC alpha under OSF1
   16490      * [57]9671: gcc.3.2.2 does not build on a HP Tru64 Unix v5.1B system
   16491 
   16492     HP-specific:
   16493 
   16494      * [58]8694: <string> breaks <ctype.h> on HP-UX 10.20 (DUP: 9275)
   16495      * [59]9953: (ada) gcc 3.2.x can't build 3.3-branch ada on HP-UX 10
   16496        (missing symbol)
   16497      * [60]10271: Floating point args don't get reloaded across function
   16498        calls with -O2
   16499 
   16500     MIPS specific:
   16501 
   16502      * [61]6362: mips-irix6 gcc-3.1 C testsuite failure with -mips4 in
   16503        compile/920501-4.c
   16504 
   16505     CRIS specific:
   16506 
   16507      * [62]10377: gcc-3.2.2 creates bad assembler code for cris
   16508 
   16509     Miscellaneous and minor bugs:
   16510 
   16511      * [63]6955: collect2 says "core dumped" when there is no core
   16512      __________________________________________________________________
   16513 
   16514 GCC 3.2.2
   16515 
   16516    Beginning with 3.2.2, GCC's Makefile suite supports redirection of make
   16517    install by means of the DESTDIR variable. Parts of the GCC tree have
   16518    featured that support long before, but now it is available even from
   16519    the top level.
   16520 
   16521    Other than that, GCC 3.2.2 is a bug fix release only; there are no new
   16522    features that were not present in GCC 3.2.1.
   16523 
   16524   Bug Fixes
   16525 
   16526    On the following i386-based systems GCC 3.2.1 broke the C ABI wrt.
   16527    functions returning structures: Cygwin, FreeBSD (GCC 3.2.1 as shipped
   16528    with FreeBSD 5.0 does not have this problem), Interix, a.out-based
   16529    GNU/Linux and NetBSD, OpenBSD, and Darwin. GCC 3.2.2 reverts this ABI
   16530    change, and thus restores ABI-compatibility with previous releases
   16531    (except GCC 3.2.1) on these platforms.
   16532 
   16533    This section lists the problem reports (PRs) from GCC's bug tracking
   16534    system that are known to be fixed in the 3.2.2 release. This list might
   16535    not be complete (that is, it is possible that some PRs that have been
   16536    fixed are not listed here) and some of the titles have been changed to
   16537    make them more clear.
   16538 
   16539     Internal Compiler Errors (multi-platform)
   16540 
   16541      * [64]5919: (c++) ICE when passing variable array to template
   16542        function
   16543      * [65]7129: (c++) ICE with min/max assignment operators (<?= and >?=)
   16544      * [66]7507: ICE with -O2 when address of called function is a
   16545        complicated expression
   16546      * [67]7622: ICE with nested inline functions if function's address is
   16547        taken
   16548      * [68]7681: (fortran) ICE in compensate_edge, in reg-stack.c (also PR
   16549        [69]9258)
   16550      * [70]8031: (c++) ICE in code comparing typeids and casting from
   16551        virtual base
   16552      * [71]8275: ICE in simplify_subreg
   16553      * [72]8332: (c++) builtin strlen/template interaction causes ICE
   16554      * [73]8372: (c++) ICE on explicit call of destructor
   16555      * [74]8439: (c, not c++) empty struct causes ICE
   16556      * [75]8442: (c++) ICE with nested template classes
   16557      * [76]8518: ICE when compiling mplayer ("extern inline" issue)
   16558      * [77]8615: (c++) ICE with out-of-range character constant template
   16559        argument
   16560      * [78]8663: (c++) ICE in cp_expr_size, at cp-lang.c:307
   16561      * [79]8799: (c++) ICE: error reporting routines re-entered
   16562      * [80]9328: (c++) ICE with typeof(X) for overloaded X
   16563      * [81]9465: (preprocessor) cpp -traditional ICE on null bytes
   16564 
   16565     C++ (compiler and library) bugs
   16566 
   16567      * [82]47: scoping in nested classes is broken
   16568      * [83]6745: problems with iostream rdbuf() member function
   16569      * [84]8214: conversion from const char* const to char* sometimes
   16570        accepted illegally
   16571      * [85]8493: builtin strlen and overload resolution (same bug as
   16572        [86]8332)
   16573      * [87]8503: strange behaviour of function types
   16574      * [88]8727: compiler confused by inheritance from an anonymous struct
   16575      * [89]7445: poor performance of std::locale::classic() in
   16576        multi-threaded applications
   16577      * [90]8230: mishandling of overflow in vector<T>::resize
   16578      * [91]8399: sync_with_stdio(false) breaks unformatted input
   16579      * [92]8662: illegal access of private member of unnamed class is
   16580        accepted
   16581      * [93]8707: "make distclean" fails in libstdc++-v3 directory
   16582      * [94]8708: __USE_MALLOC doesn't work
   16583      * [95]8790: Use of non-thread-safe strtok in src/localename.cc
   16584      * [96]8887: Bug in date formats with --enable-clocale=generic
   16585      * [97]9076: Call Frame Instructions are not handled correctly during
   16586        unwind operation
   16587      * [98]9151: std::setprecision limited to 16 digits when outputting a
   16588        double to a stream
   16589      * [99]9168: codecvt<char, char, mbstate_t> overwrites output buffers
   16590      * [100]9269: libstdc++ headers: explicit specialization of function
   16591        must precede its first use
   16592      * [101]9322: return value of basic_streambuf<>::getloc affected by
   16593        locale::global
   16594      * [102]9433: segfault in runtime support for dynamic_cast
   16595 
   16596     C and optimizer bugs
   16597 
   16598      * [103]8032: GCC incorrectly initializes static structs that have
   16599        flexible arrays
   16600      * [104]8639: simple arithmetic expression broken
   16601      * [105]8794: optimization improperly eliminates certain expressions
   16602      * [106]8832: traditional "asm volatile" code is illegally optimized
   16603      * [107]8988: loop optimizer bug: with -O2, code is generated that
   16604        segfaults (found on i386, bug present for all platforms)
   16605      * [108]9492: structure copy clobbers subsequent stores to structure
   16606 
   16607     Objective-C bugs
   16608 
   16609      * [109]9267: Objective-C parser won't build with newer bison versions
   16610        (e.g. 1.875)
   16611 
   16612     Ada bugs
   16613 
   16614      * [110]8344: Ada build problem due to conflict between gcc/final.o,
   16615        gcc/ada/final.o
   16616 
   16617     Preprocessor bugs
   16618 
   16619      * [111]8524: _Pragma within macros is improperly expanded
   16620      * [112]8880: __WCHAR_TYPE__ macro incorrectly set to "long int" with
   16621        -fshort-wchar
   16622 
   16623     ARM-specific
   16624 
   16625      * [113]9090: arm ICE with >= -O2; regression from gcc-2.95
   16626 
   16627     x86-specific (Intel/AMD)
   16628 
   16629      * [114]8588: ICE in extract_insn, at recog.c:NNNN (shift instruction)
   16630      * [115]8599: loop unroll bug with -march=k6-3
   16631      * [116]9506: ABI breakage in structure return (affects BSD and
   16632        Cygwin, but not GNU/Linux)
   16633 
   16634     FreeBSD 5.0 specific
   16635 
   16636      * [117]9484: GCC 3.2.1 Bootstrap failure on FreeBSD 5.0
   16637 
   16638     RTEMS-specific
   16639 
   16640      * [118]9292: hppa1.1-rtems configurery problems
   16641      * [119]9293: [m68k-elf/rtems] config/m68k/t-crtstuff bug
   16642      * [120]9295: [mips-rtems] config/mips/rtems.h init/fini issue
   16643      * [121]9296: gthr-rtems regression
   16644      * [122]9316: powerpc-rtems: extending multilibs
   16645 
   16646     HP-PA specific
   16647 
   16648      * [123]9493: ICE with -O2 when building a simple function
   16649 
   16650     Documentation
   16651 
   16652      * [124]7341: hyperlink to gcov in GCC documentation doesn't work
   16653      * [125]8947: Please add a warning about "-malign-double" in docs
   16654      * [126]7448, [127]8882: typo cleanups
   16655      __________________________________________________________________
   16656 
   16657 GCC 3.2.1
   16658 
   16659    3.2.1 adds a new warning, -Wabi. This option warns when GNU C++
   16660    generates code that is known not to be binary-compatible with the
   16661    vendor-neutral ia32/ia64 ABI. Please consult the GCC manual, included
   16662    in the distribution, for details.
   16663 
   16664    This release also removes an old GCC extension, "naming types", and the
   16665    documentation now directs users to use a different GCC extension,
   16666    __typeof__, instead. The feature had evidently been broken for a while.
   16667 
   16668    Otherwise, 3.2.1 is a bug fix release only; other than bug fixes and
   16669    the new warning there are no new features that were not present in GCC
   16670    3.2.
   16671 
   16672    In addition, the previous fix for [128]PR 7445 (poor performance of
   16673    std::locale::classic() in multi-threaded applications) was reverted
   16674    ("unfixed"), because the "fix" was not thread-safe.
   16675 
   16676   Bug Fixes
   16677 
   16678    This section lists the problem reports (PRs) from GCC's bug tracking
   16679    system that are known to be fixed in the 3.2.1 release. This list might
   16680    not be complete (that is, it is possible that some PRs that have been
   16681    fixed are not listed here). As you can see, the number of bug fixes is
   16682    quite large, so it is strongly recommended that users of earlier GCC
   16683    3.x releases upgrade to GCC 3.2.1.
   16684 
   16685     Internal Compiler Errors (multi-platform)
   16686 
   16687      * [129]2521: (c++) ICE in build_ptrmemfunc, in cp/typeck.c
   16688      * [130]5661: (c++) ICE instantiating template on array of unknown
   16689        size (bad code)
   16690      * [131]6419: (c++) ICE in make_decl_rtl for "longest" attribute on
   16691        64-bit platforms
   16692      * [132]6994: (c++) ICE in find_function_data
   16693      * [133]7150: preprocessor: GCC -dM -E gives an ICE
   16694      * [134]7160: ICE when optimizing branches without a return value
   16695      * [135]7228: (c++) ICE when using member template and template
   16696        function
   16697      * [136]7266: (c++) ICE with -pedantic on missing typename
   16698      * [137]7353: ICE from use of "Naming Types" extension, see above
   16699      * [138]7411: ICE in instantiate_virtual_regs_1, in function.c
   16700      * [139]7478: (c++) ICE on static_cast inside template
   16701      * [140]7526: preprocessor core dump when _Pragma implies #pragma
   16702        dependency
   16703      * [141]7721: (c++) ICE on simple (but incorrect) template ([142]7803
   16704        is a duplicate)
   16705      * [143]7754: (c++) ICE on union with template parameter
   16706      * [144]7788: (c++) redeclaring a definition as an incomplete class
   16707        causes ICE
   16708      * [145]8031: (c++) ICE in comptypes, in cp/typeck.c
   16709      * [146]8055: preprocessor dies with SIG11 when building FreeBSD
   16710        kernel
   16711      * [147]8067: (c++) ICE due to mishandling of __FUNCTION__ and related
   16712        variables
   16713      * [148]8134: (c++) ICE in force_store_init_value on legal code
   16714      * [149]8149: (c++) ICE on incomplete type
   16715      * [150]8160: (c++) ICE in build_modify_expr, in cp/typeck.c: array
   16716        initialization
   16717 
   16718     C++ (compiler and library) bugs
   16719 
   16720      * [151]5607: No pointer adjustment in covariant return types
   16721      * [152]6579: Infinite loop with statement expressions in member
   16722        initialization
   16723      * [153]6803: Default copy constructor bug in GCC 3.1
   16724      * [154]7176: g++ confused by friend and static member with same name
   16725      * [155]7188: Segfault with template class and recursive (incorrect)
   16726        initializer list
   16727      * [156]7306: Regression: GCC 3.x fails to compile code with virtual
   16728        inheritance if a method has a variable number of arguments
   16729      * [157]7461: ctype<char>::classic_table() returns offset array on
   16730        Cygwin
   16731      * [158]7524: f(const float arg[3]) fails
   16732      * [159]7584: Erroneous ambiguous base error on using declaration
   16733      * [160]7676: Member template overloading problem
   16734      * [161]7679: infinite loop when a right parenthesis is missing
   16735      * [162]7811: default locale not taken from environment
   16736      * [163]7961: compare( char *) implemented incorrectly in
   16737        basic_string<>
   16738      * [164]8071: basic_ostream::operator<<(streambuf*) loops forever if
   16739        streambuf::underflow() leaves gptr() NULL (dups: [165]8127,
   16740        [166]6745)
   16741      * [167]8096: deque::at() throws std::range_error instead of
   16742        std::out_of_range
   16743      * [168]8127: cout << cin.rdbuf() infinite loop
   16744      * [169]8218: Excessively large memory consumed for classes with large
   16745        array members
   16746      * [170]8287: GCC 3.2: Destructor called for non-constructed local
   16747        object
   16748      * [171]8347: empty vector range used in string construction causes
   16749        core dump
   16750      * [172]8348: fail() flag is set in istringstream when eof() flag is
   16751        set
   16752      * [173]8391: regression: infinite loop in cp/decl2.c(finish_file)
   16753 
   16754     C and optimizer bugs
   16755 
   16756      * [174]6627: -fno-align-functions doesn't seem to disable function
   16757        alignment
   16758      * [175]6631: life_analysis misoptimizes code to initialize fields of
   16759        a structure
   16760      * [176]7102: unsigned char division results in floating exception
   16761      * [177]7120: Run once loop should *always* be unrolled
   16762        (pessimization)
   16763      * [178]7209: Bug involving array referencing and ?: operator
   16764      * [179]7515: invalid inlining of global function with -O3
   16765      * [180]7814: incorrect scheduling for glibc-2.2.92 strcpy test
   16766      * [181]8467: bug in sibling call optimization
   16767 
   16768     Preprocessor bugs
   16769 
   16770      * [182]4890: incorrect line markers from the traditional preprocessor
   16771      * [183]7357: -M option omits system headers files (making it the same
   16772        as -MM)
   16773      * [184]7358: Changes to Sun's make Dependencies
   16774      * [185]7602: C++ header files found in CPLUS_INCLUDE_PATH treated as
   16775        C headers
   16776      * [186]7862: Interrupting GCC -MD removes .d file but not .o
   16777      * [187]8190: Failed compilation deletes -MD dependency file
   16778      * [188]8524: _Pragma within macro is improperly expanded
   16779 
   16780     x86 specific (Intel/AMD)
   16781 
   16782      * [189]5351: (i686-only) function pass-by-value structure copy
   16783        corrupts stack ([190]7591 is a duplicate)
   16784      * [191]6845, [192]7034, [193]7124, [194]7174: ICE's with
   16785        -march=pentium3/pentium2/athlon (these are all the same underlying
   16786        bug, in MMX register use)
   16787      * [195]7134, [196]7375, [197]7390: ICE with -march=athlon (maybe same
   16788        as above?)
   16789      * [198]6890: xmmintrin.h, _MM_TRANSPOSE4_PS is broken
   16790      * [199]6981: wrong code in 64-bit manipulation on x86
   16791      * [200]7242: GCC -mcpu=pentium[23] doesn't define __tune_pentiumpro__
   16792        macro
   16793      * [201]7396: ix86: cmpgt_ss, cmpge_ss, cmpngt_ss, and cmpnge_ss SSE
   16794        intrinsics are broken
   16795      * [202]7630: GCC 3.2 breaks on Mozilla 1.0's JS sources with
   16796        -march=pentium4
   16797      * [203]7693: Typo in i386 mmintrin.h header
   16798      * [204]7723: ICE - Pentium3 sse - GCC 3.2
   16799      * [205]7951: ICE on -march=pentium4 -O2 -mfpmath=sse
   16800      * [206]8146: (i686 only) gcc 3.2 miscompiles gcc 2.95.3
   16801 
   16802     PowerPC specific
   16803 
   16804      * [207]5967: GCC bug when profiling nested functions on powerpc
   16805      * [208]6984: wrong code generated with -O2, -O3, -Os for do-while
   16806        loop on PowerPC
   16807      * [209]7114: PowerPC: ICE building strcoll.op from glibc-2.2.5
   16808      * [210]7130: miscompiled code for GCC-3.1 on
   16809        powerpc-unknown-linux-gnu with -funroll-all-loops
   16810      * [211]7133: PowerPC ICE: unrecognizable insn
   16811      * [212]7380: ICE in extract_insn, at recog.c:2148
   16812      * [213]8252: ICE on Altivec code with optimization turned on
   16813      * [214]8451: Altivec ICE in GCC 3.2
   16814 
   16815     HP/PA specific
   16816 
   16817      * [215]7250: __ashrdi3 returns wrong value on 32 bit hppa
   16818 
   16819     SPARC specific
   16820 
   16821      * [216]6668: when using --disable-multilib, libgcc_s.so is installed
   16822        in the wrong place on sparc-solaris
   16823      * [217]7151: ICE when compiling for UltraSPARC
   16824      * [218]7335: SPARC: ICE in verify_wide_reg (flow.c:557) with long
   16825        double and -O1
   16826      * [219]7842: [REGRESSION] SPARC code gen bug
   16827 
   16828     ARM specific
   16829 
   16830      * [220]7856: [arm] invalid offset in constant pool reference
   16831      * [221]7967: optimization produces wrong code (ARM)
   16832 
   16833     Alpha specific
   16834 
   16835      * [222]7374: __builtin_fabsl broken on alpha
   16836 
   16837     IBM s390 specific
   16838 
   16839      * [223]7370: ICE in fixup_var_refs_1 on s390x
   16840      * [224]7409: loop optimization bug on s390x-linux-gnu
   16841      * [225]8232: s390x: ICE when using bcmp with int length argument
   16842 
   16843     SCO specific
   16844 
   16845      * [226]7623: SCO OpenServer build fails with machmode.def: undefined
   16846        symbol: BITS_PER_UNIT
   16847 
   16848     m68k/Coldfire specific
   16849 
   16850      * [227]8314: crtbegin, crtend need to be multilib'ed for this
   16851        platform
   16852 
   16853     Documentation
   16854 
   16855      * [228]761: Document some undocumented options
   16856      * [229]5610: Fix documentation about invoking SSE instructions
   16857        (-mfpmath=sse)
   16858      * [230]7484: List -Wmissing-declarations as C-only option
   16859      * [231]7531: -mcmodel not documented for x86-64
   16860      * [232]8120: Update documentation of bad use of ##
   16861      __________________________________________________________________
   16862 
   16863 GCC 3.2
   16864 
   16865    3.2 is a small bug fix release, but there is a change to the
   16866    application binary interface (ABI), hence the change to the second part
   16867    of the version number.
   16868 
   16869    The main purpose of the 3.2 release is to correct a couple of problems
   16870    in the C++ ABI, with the intention of providing a stable interface
   16871    going forward.  Accordingly, 3.2 is only a small change to 3.1.1.
   16872 
   16873   Bug Fixes
   16874 
   16875     C++
   16876 
   16877      * [233]7320: g++ 3.2 relocation problem
   16878      * [234]7470: vtable: virtual function pointers not in declaration
   16879        order
   16880 
   16881     libstdc++
   16882 
   16883      * [235]6410: Trouble with non-ASCII monetary symbols and wchar_t
   16884      * [236]6503, [237]6642, [238]7186: Problems with comparing or
   16885        subtracting various types of const and non-const iterators
   16886      * [239]7216: ambiguity with basic_iostream::traits_type
   16887      * [240]7220: problem with basic_istream::ignore(0,delimiter)
   16888      * [241]7222: locale::operator==() doesn't work on std::locale("")
   16889      * [242]7286: placement operator delete issue
   16890      * [243]7442: cxxabi.h does not match the C++ ABI
   16891      * [244]7445: poor performance of std::locale::classic() in
   16892        multi-threaded applications
   16893 
   16894     x86-64 specific
   16895 
   16896      * [245]7291: off-by-one in generated inline bzero code for x86-64
   16897 
   16898 
   16899     For questions related to the use of GCC, please consult these web
   16900     pages and the [246]GCC manuals. If that fails, the
   16901     [247]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   16902     web pages and the development of GCC are welcome on our developer
   16903     list at [248]gcc (a] gcc.gnu.org. All of [249]our lists have public
   16904     archives.
   16905 
   16906    Copyright (C) [250]Free Software Foundation, Inc. Verbatim copying and
   16907    distribution of this entire article is permitted in any medium,
   16908    provided this notice is preserved.
   16909 
   16910    These pages are [251]maintained by the GCC team. Last modified
   16911    2019-11-28[252].
   16912 
   16913 References
   16914 
   16915    1. http://gcc.gnu.org/gcc-3.2/changes.html#3.2.3
   16916    2. http://gcc.gnu.org/gcc-3.1/changes.html
   16917    3. http://gcc.gnu.org/gcc-3.2/c++-abi.html
   16918    4. https://gcc.gnu.org/PR3782
   16919    5. https://gcc.gnu.org/PR6440
   16920    6. https://gcc.gnu.org/PR7050
   16921    7. https://gcc.gnu.org/PR7741
   16922    8. https://gcc.gnu.org/PR7982
   16923    9. https://gcc.gnu.org/PR8068
   16924   10. https://gcc.gnu.org/PR8178
   16925   11. https://gcc.gnu.org/PR8396
   16926   12. https://gcc.gnu.org/PR8674
   16927   13. https://gcc.gnu.org/PR9768
   16928   14. https://gcc.gnu.org/PR9798
   16929   15. https://gcc.gnu.org/PR9799
   16930   16. https://gcc.gnu.org/PR9928
   16931   17. https://gcc.gnu.org/PR10114
   16932   18. https://gcc.gnu.org/PR10352
   16933   19. https://gcc.gnu.org/PR10336
   16934   20. https://gcc.gnu.org/PR8224
   16935   21. https://gcc.gnu.org/PR8613
   16936   22. https://gcc.gnu.org/PR8828
   16937   23. https://gcc.gnu.org/PR9226
   16938   24. https://gcc.gnu.org/PR9853
   16939   25. https://gcc.gnu.org/PR9797
   16940   26. https://gcc.gnu.org/PR9967
   16941   27. https://gcc.gnu.org/PR10116
   16942   28. https://gcc.gnu.org/PR10171
   16943   29. https://gcc.gnu.org/PR10175
   16944   30. https://gcc.gnu.org/PR8316
   16945   31. https://gcc.gnu.org/PR9169
   16946   32. https://gcc.gnu.org/PR9420
   16947   33. https://gcc.gnu.org/PR9459
   16948   34. https://gcc.gnu.org/PR9507
   16949   35. https://gcc.gnu.org/PR9538
   16950   36. https://gcc.gnu.org/PR9602
   16951   37. https://gcc.gnu.org/PR9993
   16952   38. https://gcc.gnu.org/PR10167
   16953   39. https://gcc.gnu.org/PR9652
   16954   40. https://gcc.gnu.org/PR10144
   16955   41. https://gcc.gnu.org/PR8746
   16956   42. https://gcc.gnu.org/PR9888
   16957   43. https://gcc.gnu.org/PR9638
   16958   44. https://gcc.gnu.org/PR9954
   16959   45. https://gcc.gnu.org/PR7784
   16960   46. https://gcc.gnu.org/PR7796
   16961   47. https://gcc.gnu.org/PR8281
   16962   48. https://gcc.gnu.org/PR8366
   16963   49. https://gcc.gnu.org/PR8726
   16964   50. https://gcc.gnu.org/PR9414
   16965   51. https://gcc.gnu.org/PR10067
   16966   52. https://gcc.gnu.org/PR7248
   16967   53. https://gcc.gnu.org/PR8343
   16968   54. https://gcc.gnu.org/PR9732
   16969   55. https://gcc.gnu.org/PR10073
   16970   56. https://gcc.gnu.org/PR7702
   16971   57. https://gcc.gnu.org/PR9671
   16972   58. https://gcc.gnu.org/PR8694
   16973   59. https://gcc.gnu.org/PR9953
   16974   60. https://gcc.gnu.org/PR10271
   16975   61. https://gcc.gnu.org/PR6362
   16976   62. https://gcc.gnu.org/PR10377
   16977   63. https://gcc.gnu.org/PR6955
   16978   64. https://gcc.gnu.org/PR5919
   16979   65. https://gcc.gnu.org/PR7129
   16980   66. https://gcc.gnu.org/PR7507
   16981   67. https://gcc.gnu.org/PR7622
   16982   68. https://gcc.gnu.org/PR7681
   16983   69. https://gcc.gnu.org/PR9528
   16984   70. https://gcc.gnu.org/PR8031
   16985   71. https://gcc.gnu.org/PR8275
   16986   72. https://gcc.gnu.org/PR8332
   16987   73. https://gcc.gnu.org/PR8372
   16988   74. https://gcc.gnu.org/PR8439
   16989   75. https://gcc.gnu.org/PR8442
   16990   76. https://gcc.gnu.org/PR8518
   16991   77. https://gcc.gnu.org/PR8615
   16992   78. https://gcc.gnu.org/PR8663
   16993   79. https://gcc.gnu.org/PR8799
   16994   80. https://gcc.gnu.org/PR9328
   16995   81. https://gcc.gnu.org/PR9465
   16996   82. https://gcc.gnu.org/PR47
   16997   83. https://gcc.gnu.org/PR6745
   16998   84. https://gcc.gnu.org/PR8214
   16999   85. https://gcc.gnu.org/PR8493
   17000   86. https://gcc.gnu.org/PR8332
   17001   87. https://gcc.gnu.org/PR8503
   17002   88. https://gcc.gnu.org/PR8727
   17003   89. https://gcc.gnu.org/PR7445
   17004   90. https://gcc.gnu.org/PR8230
   17005   91. https://gcc.gnu.org/PR8399
   17006   92. https://gcc.gnu.org/PR8662
   17007   93. https://gcc.gnu.org/PR8707
   17008   94. https://gcc.gnu.org/PR8708
   17009   95. https://gcc.gnu.org/PR8790
   17010   96. https://gcc.gnu.org/PR8887
   17011   97. https://gcc.gnu.org/PR9076
   17012   98. https://gcc.gnu.org/PR9151
   17013   99. https://gcc.gnu.org/PR9168
   17014  100. https://gcc.gnu.org/PR9269
   17015  101. https://gcc.gnu.org/PR9322
   17016  102. https://gcc.gnu.org/PR9433
   17017  103. https://gcc.gnu.org/PR8032
   17018  104. https://gcc.gnu.org/PR8639
   17019  105. https://gcc.gnu.org/PR8794
   17020  106. https://gcc.gnu.org/PR8832
   17021  107. https://gcc.gnu.org/PR8988
   17022  108. https://gcc.gnu.org/PR9492
   17023  109. https://gcc.gnu.org/PR9267
   17024  110. https://gcc.gnu.org/PR8344
   17025  111. https://gcc.gnu.org/PR8524
   17026  112. https://gcc.gnu.org/PR8880
   17027  113. https://gcc.gnu.org/PR9090
   17028  114. https://gcc.gnu.org/PR8588
   17029  115. https://gcc.gnu.org/PR8599
   17030  116. https://gcc.gnu.org/PR9506
   17031  117. https://gcc.gnu.org/PR9484
   17032  118. https://gcc.gnu.org/PR9292
   17033  119. https://gcc.gnu.org/PR9293
   17034  120. https://gcc.gnu.org/PR9295
   17035  121. https://gcc.gnu.org/PR9296
   17036  122. https://gcc.gnu.org/PR9316
   17037  123. https://gcc.gnu.org/PR9493
   17038  124. https://gcc.gnu.org/PR7341
   17039  125. https://gcc.gnu.org/PR8947
   17040  126. https://gcc.gnu.org/PR7448
   17041  127. https://gcc.gnu.org/PR8882
   17042  128. https://gcc.gnu.org/PR7445
   17043  129. https://gcc.gnu.org/PR2521
   17044  130. https://gcc.gnu.org/PR5661
   17045  131. https://gcc.gnu.org/PR6419
   17046  132. https://gcc.gnu.org/PR6994
   17047  133. https://gcc.gnu.org/PR7150
   17048  134. https://gcc.gnu.org/PR7160
   17049  135. https://gcc.gnu.org/PR7228
   17050  136. https://gcc.gnu.org/PR7266
   17051  137. https://gcc.gnu.org/PR7353
   17052  138. https://gcc.gnu.org/PR7411
   17053  139. https://gcc.gnu.org/PR7478
   17054  140. https://gcc.gnu.org/PR7526
   17055  141. https://gcc.gnu.org/PR7721
   17056  142. https://gcc.gnu.org/PR7803
   17057  143. https://gcc.gnu.org/PR7754
   17058  144. https://gcc.gnu.org/PR7788
   17059  145. https://gcc.gnu.org/PR8031
   17060  146. https://gcc.gnu.org/PR8055
   17061  147. https://gcc.gnu.org/PR8067
   17062  148. https://gcc.gnu.org/PR8134
   17063  149. https://gcc.gnu.org/PR8149
   17064  150. https://gcc.gnu.org/PR8160
   17065  151. https://gcc.gnu.org/PR5607
   17066  152. https://gcc.gnu.org/PR6579
   17067  153. https://gcc.gnu.org/PR6803
   17068  154. https://gcc.gnu.org/PR7176
   17069  155. https://gcc.gnu.org/PR7188
   17070  156. https://gcc.gnu.org/PR7306
   17071  157. https://gcc.gnu.org/PR7461
   17072  158. https://gcc.gnu.org/PR7524
   17073  159. https://gcc.gnu.org/PR7584
   17074  160. https://gcc.gnu.org/PR7676
   17075  161. https://gcc.gnu.org/PR7679
   17076  162. https://gcc.gnu.org/PR7811
   17077  163. https://gcc.gnu.org/PR7961
   17078  164. https://gcc.gnu.org/PR8071
   17079  165. https://gcc.gnu.org/PR8127
   17080  166. https://gcc.gnu.org/PR6745
   17081  167. https://gcc.gnu.org/PR8096
   17082  168. https://gcc.gnu.org/PR8127
   17083  169. https://gcc.gnu.org/PR8218
   17084  170. https://gcc.gnu.org/PR8287
   17085  171. https://gcc.gnu.org/PR8347
   17086  172. https://gcc.gnu.org/PR8348
   17087  173. https://gcc.gnu.org/PR8391
   17088  174. https://gcc.gnu.org/PR6627
   17089  175. https://gcc.gnu.org/PR6631
   17090  176. https://gcc.gnu.org/PR7102
   17091  177. https://gcc.gnu.org/PR7120
   17092  178. https://gcc.gnu.org/PR7209
   17093  179. https://gcc.gnu.org/PR7515
   17094  180. https://gcc.gnu.org/PR7814
   17095  181. https://gcc.gnu.org/PR8467
   17096  182. https://gcc.gnu.org/PR4890
   17097  183. https://gcc.gnu.org/PR7357
   17098  184. https://gcc.gnu.org/PR7358
   17099  185. https://gcc.gnu.org/PR7602
   17100  186. https://gcc.gnu.org/PR7862
   17101  187. https://gcc.gnu.org/PR8190
   17102  188. https://gcc.gnu.org/PR8524
   17103  189. https://gcc.gnu.org/PR5351
   17104  190. https://gcc.gnu.org/PR7591
   17105  191. https://gcc.gnu.org/PR6845
   17106  192. https://gcc.gnu.org/PR7034
   17107  193. https://gcc.gnu.org/PR7124
   17108  194. https://gcc.gnu.org/PR7174
   17109  195. https://gcc.gnu.org/PR7134
   17110  196. https://gcc.gnu.org/PR7375
   17111  197. https://gcc.gnu.org/PR7390
   17112  198. https://gcc.gnu.org/PR6890
   17113  199. https://gcc.gnu.org/PR6981
   17114  200. https://gcc.gnu.org/PR7242
   17115  201. https://gcc.gnu.org/PR7396
   17116  202. https://gcc.gnu.org/PR7630
   17117  203. https://gcc.gnu.org/PR7693
   17118  204. https://gcc.gnu.org/PR7723
   17119  205. https://gcc.gnu.org/PR7951
   17120  206. https://gcc.gnu.org/PR8146
   17121  207. https://gcc.gnu.org/PR5967
   17122  208. https://gcc.gnu.org/PR6984
   17123  209. https://gcc.gnu.org/PR7114
   17124  210. https://gcc.gnu.org/PR7130
   17125  211. https://gcc.gnu.org/PR7133
   17126  212. https://gcc.gnu.org/PR7380
   17127  213. https://gcc.gnu.org/PR8252
   17128  214. https://gcc.gnu.org/PR8451
   17129  215. https://gcc.gnu.org/PR7250
   17130  216. https://gcc.gnu.org/PR6668
   17131  217. https://gcc.gnu.org/PR7151
   17132  218. https://gcc.gnu.org/PR7335
   17133  219. https://gcc.gnu.org/PR7842
   17134  220. https://gcc.gnu.org/PR7856
   17135  221. https://gcc.gnu.org/PR7967
   17136  222. https://gcc.gnu.org/PR7374
   17137  223. https://gcc.gnu.org/PR7370
   17138  224. https://gcc.gnu.org/PR7409
   17139  225. https://gcc.gnu.org/PR8232
   17140  226. https://gcc.gnu.org/PR7623
   17141  227. https://gcc.gnu.org/PR8314
   17142  228. https://gcc.gnu.org/PR761
   17143  229. https://gcc.gnu.org/PR5610
   17144  230. https://gcc.gnu.org/PR7484
   17145  231. https://gcc.gnu.org/PR7531
   17146  232. https://gcc.gnu.org/PR8120
   17147  233. https://gcc.gnu.org/PR7320
   17148  234. https://gcc.gnu.org/PR7470
   17149  235. https://gcc.gnu.org/PR6410
   17150  236. https://gcc.gnu.org/PR6503
   17151  237. https://gcc.gnu.org/PR6642
   17152  238. https://gcc.gnu.org/PR7186
   17153  239. https://gcc.gnu.org/PR7216
   17154  240. https://gcc.gnu.org/PR7220
   17155  241. https://gcc.gnu.org/PR7222
   17156  242. https://gcc.gnu.org/PR7286
   17157  243. https://gcc.gnu.org/PR7442
   17158  244. https://gcc.gnu.org/PR7445
   17159  245. https://gcc.gnu.org/PR7291
   17160  246. https://gcc.gnu.org/onlinedocs/
   17161  247. mailto:gcc-help (a] gcc.gnu.org
   17162  248. mailto:gcc (a] gcc.gnu.org
   17163  249. https://gcc.gnu.org/lists.html
   17164  250. https://www.fsf.org/
   17165  251. https://gcc.gnu.org/about.html
   17166  252. http://validator.w3.org/check/referer
   17167 ======================================================================
   17168 http://gcc.gnu.org/gcc-3.1/index.html
   17169                                     GCC 3.1
   17170 
   17171    (This release series is no longer supported.)
   17172 
   17173    July 27, 2002
   17174 
   17175    The [1]GNU project and the GCC developers are pleased to announce the
   17176    release of GCC 3.1.1.
   17177 
   17178    The links below still apply to GCC 3.1.1.
   17179 
   17180    May 15, 2002
   17181 
   17182    The [2]GNU project and the GCC developers are pleased to announce the
   17183    release of GCC 3.1.
   17184 
   17185    GCC used to stand for the GNU C Compiler, but since the compiler
   17186    supports several other languages aside from C, it now stands for the
   17187    GNU Compiler Collection.
   17188 
   17189    A list of [3]successful builds is updated as new information becomes
   17190    available.
   17191 
   17192    The GCC developers would like to thank the numerous people that have
   17193    contributed [4]new features, improvements, bug fixes, and other changes
   17194    as well as test results to GCC. This [5]amazing group of volunteers is
   17195    what makes GCC successful.
   17196 
   17197    For additional information about GCC please refer to the [6]GCC project
   17198    web site or contact the [7]GCC development mailing list.
   17199 
   17200    To obtain GCC please use [8]our mirror sites, or our CVS server.
   17201      __________________________________________________________________
   17202 
   17203 
   17204     For questions related to the use of GCC, please consult these web
   17205     pages and the [9]GCC manuals. If that fails, the
   17206     [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17207     web pages and the development of GCC are welcome on our developer
   17208     list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public
   17209     archives.
   17210 
   17211    Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and
   17212    distribution of this entire article is permitted in any medium,
   17213    provided this notice is preserved.
   17214 
   17215    These pages are [14]maintained by the GCC team. Last modified
   17216    2019-11-28[15].
   17217 
   17218 References
   17219 
   17220    1. http://www.gnu.org/
   17221    2. http://www.gnu.org/
   17222    3. http://gcc.gnu.org/gcc-3.1/buildstat.html
   17223    4. http://gcc.gnu.org/gcc-3.1/changes.html
   17224    5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   17225    6. http://gcc.gnu.org/index.html
   17226    7. mailto:gcc (a] gcc.gnu.org
   17227    8. http://gcc.gnu.org/mirrors.html
   17228    9. https://gcc.gnu.org/onlinedocs/
   17229   10. mailto:gcc-help (a] gcc.gnu.org
   17230   11. mailto:gcc (a] gcc.gnu.org
   17231   12. https://gcc.gnu.org/lists.html
   17232   13. https://www.fsf.org/
   17233   14. https://gcc.gnu.org/about.html
   17234   15. http://validator.w3.org/check/referer
   17235 ======================================================================
   17236 http://gcc.gnu.org/gcc-3.1/changes.html
   17237                              GCC 3.1 Release Series
   17238                         Changes, New Features, and Fixes
   17239 
   17240 Additional changes in GCC 3.1.1
   17241 
   17242      * A bug related to how structures and unions are returned has been
   17243        fixed for powerpc-*-netbsd*.
   17244      * An important bug in the implementation of -fprefetch-loop-arrays
   17245        has been fixed. Previously the optimization prefetched random
   17246        blocks of memory for most targets except for i386.
   17247      * The Java compiler now compiles Java programs much faster and also
   17248        works with parallel make.
   17249      * Nested functions have been fixed for mips*-*-netbsd*.
   17250      * Some missing floating point support routines have beed added for
   17251        mips*-*-netbsd*.
   17252      * This [1]message gives additional information about the bugs fixed
   17253        in this release.
   17254 
   17255 Caveats
   17256 
   17257      * The -traditional C compiler option has been deprecated and will be
   17258        removed in GCC 3.3. (It remains possible to preprocess non-C code
   17259        with the traditional preprocessor.)
   17260      * The default debugging format for most ELF platforms (including
   17261        GNU/Linux and FreeBSD; notable exception is Solaris) has changed
   17262        from stabs to DWARF2. This requires GDB 5.1.1 or later.
   17263 
   17264 General Optimizer Improvements
   17265 
   17266      * Jan Hubicka, SuSE Labs, together with Richard Henderson, Red Hat,
   17267        and Andreas Jaeger, SuSE Labs, has contributed [2]infrastructure
   17268        for profile driven optimizations.
   17269        Options -fprofile-arcs and -fbranch-probabilities can now be used
   17270        to improve speed of the generated code by profiling the actual
   17271        program behaviour on typical runs. In the absence of profile info
   17272        the compiler attempts to guess the profile statically.
   17273      * [3]SPEC2000 and SPEC95 benchmark suites are now used daily to
   17274        monitor performance of the generated code.
   17275        According to the SPECInt2000 results on an AMD Athlon CPU, the code
   17276        generated by GCC 3.1 is 6% faster on the average (8.2% faster with
   17277        profile feedback) compared to GCC 3.0. The code produced by GCC 3.0
   17278        is about 2.1% faster compared to 2.95.3. Tests were done using the
   17279        -O2 -march=athlon command-line options.
   17280      * Alexandre Oliva, of Red Hat, has generalized the tree inlining
   17281        infrastructure developed by CodeSourcery, LLC for the C++ front
   17282        end, so that it is now used in the C front end too. Inlining
   17283        functions as trees exposes them earlier to the compiler, giving it
   17284        more opportunities for optimization.
   17285      * Support for data prefetching instructions has been added to the GCC
   17286        back end and several targets. A new __builtin_prefetch intrinsic is
   17287        available to explicitly insert prefetch instructions and
   17288        experimental support for loop array prefetching has been added (see
   17289        -fprefetch-loop-array documentation).
   17290      * Support for emitting debugging information for macros has been
   17291        added for DWARF2. It is activated using -g3.
   17292 
   17293 New Languages and Language specific improvements
   17294 
   17295   C/C++
   17296 
   17297      * A few more [4]ISO C99 features.
   17298      * The preprocessor is 10-50% faster than the preprocessor in GCC 3.0.
   17299      * The preprocessor's symbol table has been merged with the symbol
   17300        table of the C, C++ and Objective-C front ends.
   17301      * The preprocessor consumes less memory than the preprocessor in GCC
   17302        3.0, often significantly so. On normal input files, it typically
   17303        consumes less memory than pre-3.0 cccp-based GCC, too.
   17304 
   17305   C++
   17306 
   17307      * -fhonor-std and -fno-honor-std have been removed. -fno-honor-std
   17308        was a workaround to allow std compliant code to work with the
   17309        non-std compliant libstdc++-v2. libstdc++-v3 is std compliant.
   17310      * The C++ ABI has been fixed so that void (A::*)() const is mangled
   17311        as "M1AKFvvE", rather than "MK1AFvvE" as before. This change only
   17312        affects pointer to cv-qualified member function types.
   17313      * The C++ ABI has been changed to correctly handle this code:
   17314     struct A {
   17315       void operator delete[] (void *, size_t);
   17316     };
   17317 
   17318     struct B : public A {
   17319     };
   17320 
   17321     new B[10];
   17322 
   17323        The amount of storage allocated for the array will be greater than
   17324        it was in 3.0, in order to store the number of elements in the
   17325        array, so that the correct size can be passed to operator delete[]
   17326        when the array is deleted. Previously, the value passed to operator
   17327        delete[] was unpredictable.
   17328        This change will only affect code that declares a two-argument
   17329        operator delete[] with a second parameter of type size_t in a base
   17330        class, and does not override that definition in a derived class.
   17331      * The C++ ABI has been changed so that:
   17332     struct A {
   17333       void operator delete[] (void *, size_t);
   17334       void operator delete[] (void *);
   17335     };
   17336 
   17337        does not cause unnecessary storage to be allocated when an array of
   17338        A objects is allocated.
   17339        This change will only affect code that declares both of these forms
   17340        of operator delete[], and declared the two-argument form before the
   17341        one-argument form.
   17342      * The C++ ABI has been changed so that when a parameter is passed by
   17343        value, any cleanup for that parameter is performed in the caller,
   17344        as specified by the ia64 C++ ABI, rather than the called function
   17345        as before. As a result, classes with a non-trivial destructor but a
   17346        trivial copy constructor will be passed and returned by invisible
   17347        reference, rather than by bitwise copy as before.
   17348      * G++ now supports the "named return value optimization": for code
   17349        like
   17350     A f () {
   17351       A a;
   17352       ...
   17353       return a;
   17354     }
   17355 
   17356        G++ will allocate a in the return value slot, so that the return
   17357        becomes a no-op. For this to work, all return statements in the
   17358        function must return the same variable.
   17359      * Improvements to the C++ library are listed in [5]the libstdc++-v3
   17360        FAQ.
   17361 
   17362   Objective-C
   17363 
   17364      * Annoying linker warnings (due to incorrect code being generated)
   17365        have been fixed.
   17366      * If a class method cannot be found, the compiler no longer issues a
   17367        warning if a corresponding instance method exists in the root
   17368        class.
   17369      * Forward @protocol declarations have been fixed.
   17370      * Loading of categories has been fixed in certain situations (GNU run
   17371        time only).
   17372      * The class lookup in the run-time library has been rewritten so that
   17373        class method dispatch is more than twice as fast as it used to be
   17374        (GNU run time only).
   17375 
   17376   Java
   17377 
   17378      * libgcj now includes RMI, java.lang.ref.*, javax.naming, and
   17379        javax.transaction.
   17380      * Property files and other system resources can be compiled into
   17381        executables which use libgcj using the new gcj --resource feature.
   17382      * libgcj has been ported to more platforms. In particular there is
   17383        now a mostly-functional mingw32 (Windows) target port.
   17384      * JNI and CNI invocation interfaces were implemented, so gcj-compiled
   17385        Java code can now be called from a C/C++ application.
   17386      * gcj can now use builtin functions for certain known methods, for
   17387        instance Math.cos.
   17388      * gcj can now automatically remove redundant array-store checks in
   17389        some common cases.
   17390      * The --no-store-checks optimization option was added. This can be
   17391        used to omit runtime store checks for code which is known not to
   17392        throw ArrayStoreException
   17393      * The following third party interface standards were added to libgcj:
   17394        org.w3c.dom and org.xml.sax.
   17395      * java.security has been merged with GNU Classpath. The new package
   17396        is now JDK 1.2 compliant, and much more complete.
   17397      * A bytecode verifier was added to the libgcj interpreter.
   17398      * java.lang.Character was rewritten to comply with the Unicode 3.0
   17399        standard, and improve performance.
   17400      * Partial support for many more locales was added to libgcj.
   17401      * Socket timeouts have been implemented.
   17402      * libgcj has been merged into a single shared library. There are no
   17403        longer separate shared libraries for the garbage collector and
   17404        zlib.
   17405      * Several performance improvements were made to gcj and libgcj:
   17406           + Hash synchronization (thin locks)
   17407           + A special allocation path for finalizer-free objects
   17408           + Thread-local allocation
   17409           + Parallel GC, and other GC tweaks
   17410 
   17411   Fortran
   17412 
   17413    Fortran improvements are listed in [6]the Fortran documentation.
   17414 
   17415   Ada
   17416 
   17417    [7]AdaCore, has contributed its GNAT Ada 95 front end and associated
   17418    tools. The GNAT compiler fully implements the Ada language as defined
   17419    by the ISO/IEC 8652 standard.
   17420 
   17421    Please note that the integration of the Ada front end is still work in
   17422    progress.
   17423 
   17424 New Targets and Target Specific Improvements
   17425 
   17426      * Hans-Peter Nilsson has contributed a port to MMIX, the CPU
   17427        architecture used in new editions of Donald E. Knuth's The Art of
   17428        Computer Programming.
   17429      * Axis Communications has contributed its port to the CRIS CPU
   17430        architecture, used in the ETRAX system-on-a-chip series.
   17431      * Alexandre Oliva, of Red Hat, has contributed a port to the SuperH
   17432        SH5 64-bit RISC microprocessor architecture, extending the existing
   17433        SH port.
   17434      * UltraSPARC is fully supported in 64-bit mode. The option -m64
   17435        enables it.
   17436      * For compatibility with the Sun compiler #pragma redefine_extname
   17437        has been implemented on Solaris.
   17438      * The x86 back end has had some noticeable work done to it.
   17439           + SuSE Labs developers Jan Hubicka, Bo Thorsen and Andreas
   17440             Jaeger have contributed a port to the AMD x86-64 architecture.
   17441             For more information on x86-64 see http://www.x86-64.org.
   17442           + The compiler now supports MMX, 3DNow!, SSE, and SSE2
   17443             instructions. Options -mmmx, -m3dnow, -msse, and -msse2 will
   17444             enable the respective instruction sets. Intel C++ compatible
   17445             MMX/3DNow!/SSE intrinsics are implemented. SSE2 intrinsics
   17446             will be added in next major release.
   17447           + Following those improvements, targets for Pentium MMX, K6-2,
   17448             K6-3, Pentium III, Pentium 4, and Athlon 4 Mobile/XP/MP were
   17449             added. Refer to the documentation on -march= and -mcpu=
   17450             options for details.
   17451           + For those targets that support it, -mfpmath=sse will cause the
   17452             compiler to generate SSE/SSE2 instructions for floating point
   17453             math instead of x87 instructions. Usually, this will lead to
   17454             quicker code  especially on the Pentium 4. Note that only
   17455             scalar floating point instructions are used and GCC does not
   17456             exploit SIMD features yet.
   17457           + Prefetch support has been added to the Pentium III, Pentium 4,
   17458             K6-2, K6-3, and Athlon series.
   17459           + Code generated for floating point to integer conversions has
   17460             been improved leading to better performance of many 3D
   17461             applications.
   17462      * The PowerPC back end has added 64-bit PowerPC GNU/Linux support.
   17463      * C++ support for AIX has been improved.
   17464      * Aldy Hernandez, of Red Hat, Inc, has contributed extensions to the
   17465        PowerPC port supporting the AltiVec programming model (SIMD). The
   17466        support, though presently useful, is experimental and is expected
   17467        to stabilize for 3.2. The support is written to conform to
   17468        Motorola's AltiVec specs. See -maltivec.
   17469 
   17470 Obsolete Systems
   17471 
   17472    Support for a number of older systems has been declared obsolete in GCC
   17473    3.1. Unless there is activity to revive them, the next release of GCC
   17474    will have their sources permanently removed.
   17475 
   17476    All configurations of the following processor architectures have been
   17477    declared obsolete:
   17478      * MIL-STD-1750A, 1750a-*-*
   17479      * AMD A29k, a29k-*-*
   17480      * Convex, c*-convex-*
   17481      * Clipper, clipper-*-*
   17482      * Elxsi, elxsi-*-*
   17483      * Intel i860, i860-*-*
   17484      * Sun picoJava, pj-*-* and pjl-*-*
   17485      * Western Electric 32000, we32k-*-*
   17486 
   17487    Most configurations of the following processor architectures have been
   17488    declared obsolete, but we are preserving a few systems which may have
   17489    active developers. It is unlikely that the remaining systems will
   17490    survive much longer unless we see definite signs of port activity.
   17491      * Motorola 88000 except
   17492           + Generic a.out, m88k-*-aout*
   17493           + Generic SVR4, m88k-*-sysv4
   17494           + OpenBSD, m88k-*-openbsd*
   17495      * NS32k except
   17496           + NetBSD, ns32k-*-netbsd*
   17497           + OpenBSD, ns32k-*-openbsd*.
   17498      * ROMP except
   17499           + OpenBSD, romp-*-openbsd*.
   17500 
   17501    Finally, only some configurations of these processor architectures are
   17502    being obsoleted.
   17503      * Alpha:
   17504           + OSF/1, alpha*-*-osf[123]*. (Digital Unix and Tru64 Unix, aka
   17505             alpha*-*-osf[45], are still supported.)
   17506      * ARM:
   17507           + RISCiX, arm-*-riscix*.
   17508      * i386:
   17509           + 386BSD, i?86-*-bsd*
   17510           + Chorus, i?86-*-chorusos*
   17511           + DG/UX, i?86-*-dgux*
   17512           + FreeBSD 1.x, i?86-*-freebsd1.*
   17513           + IBM AIX, i?86-*-aix*
   17514           + ISC UNIX, i?86-*-isc*
   17515           + GNU/Linux with pre-BFD linker, i?86-*-linux*oldld*
   17516           + NEXTstep, i?86-next-*
   17517           + OSF UNIX, i?86-*-osf1* and i?86-*-osfrose*
   17518           + RTEMS/coff, i?86-*-rtemscoff*
   17519           + RTEMS/go32, i?86-go32-rtems*
   17520           + Sequent/BSD, i?86-sequent-bsd*
   17521           + Sequent/ptx before version 3, i?86-sequent-ptx[12]* and
   17522             i?86-sequent-sysv3*
   17523           + SunOS, i?86-*-sunos*
   17524      * Motorola 68000:
   17525           + Altos, m68[k0]*-altos-*
   17526           + Apollo, m68[k0]*-apollo-*
   17527           + Apple A/UX, m68[k0]*-apple-*
   17528           + Bull, m68[k0]*-bull-*
   17529           + Convergent, m68[k0]*-convergent-*
   17530           + Generic SVR3, m68[k0]*-*-sysv3*
   17531           + ISI, m68[k0]*-isi-*
   17532           + LynxOS, m68[k0]*-*-lynxos*
   17533           + NEXT, m68[k0]*-next-*
   17534           + RTEMS/coff, m68[k0]*-*-rtemscoff*
   17535           + Sony, m68[k0]*-sony-*
   17536      * MIPS:
   17537           + DEC Ultrix, mips-*-ultrix* and mips-dec-*
   17538           + Generic BSD, mips-*-bsd*
   17539           + Generic System V, mips-*-sysv*
   17540           + IRIX before version 5, mips-sgi-irix[1234]*
   17541           + RiscOS, mips-*-riscos*
   17542           + Sony, mips-sony-*
   17543           + Tandem, mips-tandem-*
   17544      * SPARC:
   17545           + RTEMS/a.out, sparc-*-rtemsaout*.
   17546 
   17547 Documentation improvements
   17548 
   17549      * The old manual ("Using and Porting the GNU Compiler Collection")
   17550        has been replaced by a users manual ("Using the GNU Compiler
   17551        Collection") and a separate internals reference manual ("GNU
   17552        Compiler Collection Internals").
   17553      * More complete and much improved documentation about GCC's internal
   17554        representation used by the C and C++ front ends.
   17555      * Many cleanups and improvements in general.
   17556 
   17557 
   17558     For questions related to the use of GCC, please consult these web
   17559     pages and the [8]GCC manuals. If that fails, the
   17560     [9]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17561     web pages and the development of GCC are welcome on our developer
   17562     list at [10]gcc (a] gcc.gnu.org. All of [11]our lists have public
   17563     archives.
   17564 
   17565    Copyright (C) [12]Free Software Foundation, Inc. Verbatim copying and
   17566    distribution of this entire article is permitted in any medium,
   17567    provided this notice is preserved.
   17568 
   17569    These pages are [13]maintained by the GCC team. Last modified
   17570    2019-11-28[14].
   17571 
   17572 References
   17573 
   17574    1. https://gcc.gnu.org/ml/gcc/2002-07/msg01208.html
   17575    2. http://gcc.gnu.org/news/profiledriven.html
   17576    3. http://gcc.gnu.org/benchmarks/
   17577    4. http://gcc.gnu.org/c99status.html
   17578    5. https://gcc.gnu.org/onlinedocs/libstdc++/faq.html
   17579    6. https://gcc.gnu.org/onlinedocs/gcc-3.1.1/g77/News.html
   17580    7. https://www.adacore.com/
   17581    8. https://gcc.gnu.org/onlinedocs/
   17582    9. mailto:gcc-help (a] gcc.gnu.org
   17583   10. mailto:gcc (a] gcc.gnu.org
   17584   11. https://gcc.gnu.org/lists.html
   17585   12. https://www.fsf.org/
   17586   13. https://gcc.gnu.org/about.html
   17587   14. http://validator.w3.org/check/referer
   17588 ======================================================================
   17589 http://gcc.gnu.org/gcc-3.0/index.html
   17590                                    GCC 3.0.4
   17591 
   17592    (This release series is no longer supported.)
   17593 
   17594    February 20, 2002
   17595 
   17596    The [1]GNU project and the GCC developers are pleased to announce the
   17597    release of GCC 3.0.4, which is a bug-fix release for the GCC 3.0
   17598    series.
   17599 
   17600    GCC used to stand for the GNU C Compiler, but since the compiler
   17601    supports several other languages aside from C, it now stands for the
   17602    GNU Compiler Collection.
   17603 
   17604    GCC 3.0.x has several new optimizations, new targets, new languages and
   17605    many other new features, relative to GCC 2.95.x. See the [2]new
   17606    features page for a more complete list.
   17607 
   17608    A list of [3]successful builds is updated as new information becomes
   17609    available.
   17610 
   17611    The GCC developers would like to thank the numerous people that have
   17612    contributed new features, test results, bug fixes, etc to GCC. This
   17613    [4]amazing group of volunteers is what makes GCC successful.
   17614 
   17615    And finally, we can't in good conscience fail to mention some
   17616    [5]caveats to using GCC 3.0.x.
   17617 
   17618    For additional information about GCC please refer to the [6]GCC project
   17619    web site or contact the [7]GCC development mailing list.
   17620 
   17621    To obtain GCC please use [8]our mirror sites, or our CVS server.
   17622      __________________________________________________________________
   17623 
   17624 Previous 3.0.x Releases
   17625 
   17626    December 20, 2001: GCC 3.0.3 has been released.
   17627    October 25, 2001: GCC 3.0.2 has been released.
   17628    August 20, 2001: GCC 3.0.1 has been released.
   17629    June 18, 2001: GCC 3.0 has been released.
   17630 
   17631 
   17632     For questions related to the use of GCC, please consult these web
   17633     pages and the [9]GCC manuals. If that fails, the
   17634     [10]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17635     web pages and the development of GCC are welcome on our developer
   17636     list at [11]gcc (a] gcc.gnu.org. All of [12]our lists have public
   17637     archives.
   17638 
   17639    Copyright (C) [13]Free Software Foundation, Inc. Verbatim copying and
   17640    distribution of this entire article is permitted in any medium,
   17641    provided this notice is preserved.
   17642 
   17643    These pages are [14]maintained by the GCC team. Last modified
   17644    2019-11-28[15].
   17645 
   17646 References
   17647 
   17648    1. http://www.gnu.org/
   17649    2. http://gcc.gnu.org/gcc-3.0/features.html
   17650    3. http://gcc.gnu.org/gcc-3.0/buildstat.html
   17651    4. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   17652    5. http://gcc.gnu.org/gcc-3.0/caveats.html
   17653    6. http://gcc.gnu.org/index.html
   17654    7. mailto:gcc (a] gcc.gnu.org
   17655    8. http://gcc.gnu.org/mirrors.html
   17656    9. https://gcc.gnu.org/onlinedocs/
   17657   10. mailto:gcc-help (a] gcc.gnu.org
   17658   11. mailto:gcc (a] gcc.gnu.org
   17659   12. https://gcc.gnu.org/lists.html
   17660   13. https://www.fsf.org/
   17661   14. https://gcc.gnu.org/about.html
   17662   15. http://validator.w3.org/check/referer
   17663 ======================================================================
   17664 http://gcc.gnu.org/gcc-3.0/features.html
   17665                               GCC 3.0 New Features
   17666 
   17667 Additional changes in GCC 3.0.4
   17668 
   17669      * GCC 3.0 now supports newer versions of the [1]NetBSD operating
   17670        system, which use the ELF object file format, on x86 processors.
   17671      * Correct debugging information is generated from functions that have
   17672        lines from multiple files (e.g. yacc output).
   17673      * A fix for whitespace handling in the -traditional preprocessor,
   17674        which can affect Fortran.
   17675      * Fixes to the exception handling runtime.
   17676      * More fixes for bad code generation in C++.
   17677      * A fix for shared library generation under AIX 4.3.
   17678      * Documentation updates.
   17679      * Port of GCC to Tensilica's Xtensa processor contributed.
   17680      * A fix for compiling the PPC Linux kernel (FAT fs wouldn't link).
   17681 
   17682 Additional changes in GCC 3.0.3
   17683 
   17684      * A fix to correct an accidental change to the PowerPC ABI.
   17685      * Fixes for bad code generation on a variety of architectures.
   17686      * Improvements to the debugging information generated for C++
   17687        classes.
   17688      * Fixes for bad code generation in C++.
   17689      * A fix to avoid crashes in the C++ demangler.
   17690      * A fix to the C++ standard library to avoid buffer overflows.
   17691      * Miscellaneous improvements for a variety of architectures.
   17692 
   17693 Additional changes in GCC 3.0.2
   17694 
   17695      * Fixes for bad code generation during loop unrolling.
   17696      * Fixes for bad code generation by the sibling call optimization.
   17697      * Minor improvements to x86 code generation.
   17698      * Implementation of function descriptors in C++ vtables for IA64.
   17699      * Numerous minor bug-fixes.
   17700 
   17701 Additional changes in GCC 3.0.1
   17702 
   17703      * C++ fixes for incorrect code-generation.
   17704      * Improved cross-compiling support for the C++ standard library.
   17705      * Fixes for some embedded targets that worked in GCC 2.95.3, but not
   17706        in GCC 3.0.
   17707      * Fixes for various exception-handling bugs.
   17708      * A port to the S/390 architecture.
   17709 
   17710 General Optimizer Improvements
   17711 
   17712      * [2]Basic block reordering pass.
   17713      * New if-conversion pass with support for conditional (predicated)
   17714        execution.
   17715      * New tail call and sibling call elimination optimizations.
   17716      * New register renaming pass.
   17717      * New (experimental) [3]static single assignment (SSA) representation
   17718        support.
   17719      * New dead-code elimination pass implemented using the SSA
   17720        representation.
   17721      * [4]Global null pointer test elimination.
   17722      * [5]Global code hoisting/unification.
   17723      * More builtins and optimizations for stdio.h, string.h and old BSD
   17724        functions, as well as for ISO C99 functions.
   17725      * New builtin __builtin_expect for giving hints to the branch
   17726        predictor.
   17727 
   17728 New Languages and Language specific improvements
   17729 
   17730      * The GNU Compiler for the Java(TM) language (GCJ) is now integrated
   17731        and supported, including the run-time library containing most
   17732        common non-GUI Java classes, a bytecode interpreter, and the Boehm
   17733        conservative garbage collector. Many bugs have been fixed. GCJ can
   17734        compile Java source or Java bytecodes to either native code or Java
   17735        class files, and supports native methods written in either the
   17736        standard JNI or the more efficient and convenient CNI.
   17737      * Here is a [6]partial list of C++ improvements, both new features
   17738        and those no longer supported.
   17739      * New C++ ABI. On the IA-64 platform GCC is capable of
   17740        inter-operating with other IA-64 compilers.
   17741      * The new ABI also significantly reduces the size of symbol and debug
   17742        information.
   17743      * New C++ support library and many C++ bug fixes, vastly improving
   17744        our conformance to the ISO C++ standard.
   17745      * New [7]inliner for C++.
   17746      * Rewritten C preprocessor, integrated into the C, C++ and Objective
   17747        C compilers, with very many improvements including ISO C99 support
   17748        and [8]improvements to dependency generation.
   17749      * Support for more [9]ISO C99 features.
   17750      * Many improvements to support for checking calls to format functions
   17751        such as printf and scanf, including support for ISO C99 format
   17752        features, extensions from the Single Unix Specification and GNU
   17753        libc 2.2, checking of strfmon formats and features to assist in
   17754        auditing for format string security bugs.
   17755      * New warnings for C code that may have undefined semantics because
   17756        of violations of sequence point rules in the C standard (such as a
   17757        = a++;, a[n] = b[n++]; and a[i++] = i;), included in -Wall.
   17758      * Additional warning option -Wfloat-equal.
   17759      * Improvements to -Wtraditional.
   17760      * Fortran improvements are listed in [10]the Fortran documentation.
   17761 
   17762 New Targets and Target Specific Improvements
   17763 
   17764      * New x86 back end, generating much improved code.
   17765      * Support for a generic i386-elf target contributed.
   17766      * New option to emit x86 assembly code using Intel style syntax
   17767        (-mintel-syntax).
   17768      * HPUX 11 support contributed.
   17769      * Improved PowerPC code generation, including scheduled prologue and
   17770        epilogue.
   17771      * Port of GCC to Intel's IA-64 processor contributed.
   17772      * Port of GCC to Motorola's MCore 210 and 340 contributed.
   17773      * New unified back-end for Arm, Thumb and StrongArm contributed.
   17774      * Port of GCC to Intel's XScale processor contributed.
   17775      * Port of GCC to Atmel's AVR microcontrollers contributed.
   17776      * Port of GCC to Mitsubishi's D30V processor contributed.
   17777      * Port of GCC to Matsushita's AM33 processor (a member of the MN10300
   17778        processor family) contributed.
   17779      * Port of GCC to Fujitsu's FR30 processor contributed.
   17780      * Port of GCC to Motorola's 68HC11 and 68HC12 processors contributed.
   17781      * Port of GCC to Sun's picoJava processor core contributed.
   17782 
   17783 Documentation improvements
   17784 
   17785      * Substantially rewritten and improved C preprocessor manual.
   17786      * Many improvements to other documentation.
   17787      * Manpages for gcc, cpp and gcov are now generated automatically from
   17788        the master Texinfo manual, eliminating the problem of manpages
   17789        being out of date. (The generated manpages are only extracts from
   17790        the full manual, which is provided in Texinfo form, from which
   17791        info, HTML, other formats and a printed manual can be generated.)
   17792      * Generated info files are included in the release tarballs alongside
   17793        their Texinfo sources, avoiding problems on some platforms with
   17794        building makeinfo as part of the GCC distribution.
   17795 
   17796 Other significant improvements
   17797 
   17798      * Garbage collection used internally by the compiler for most memory
   17799        allocation instead of obstacks.
   17800      * Lengauer and Tarjan algorithm used for computing dominators in the
   17801        CFG. This algorithm can be significantly faster and more space
   17802        efficient than our older algorithm.
   17803      * gccbug script provided to assist in submitting bug reports to our
   17804        bug tracking system. (Bug reports previously submitted directly to
   17805        our mailing lists, for which you received no bug tracking number,
   17806        should be submitted again using gccbug if you can reproduce the
   17807        problem with GCC 3.0.)
   17808      * The internal libgcc library is [11]built as a shared library on
   17809        systems that support it.
   17810      * Extensive testsuite included with GCC, with many new tests. In
   17811        addition to tests for GCC bugs that have been fixed, many tests
   17812        have been added for language features, compiler warnings and
   17813        builtin functions.
   17814      * Additional language-independent warning options -Wpacked, -Wpadded,
   17815        -Wunreachable-code and -Wdisabled-optimization.
   17816      * Target-independent options -falign-functions, -falign-loops and
   17817        -falign-jumps.
   17818 
   17819    Plus a great many bug fixes and almost all the [12]features found in
   17820    GCC 2.95.
   17821 
   17822 
   17823     For questions related to the use of GCC, please consult these web
   17824     pages and the [13]GCC manuals. If that fails, the
   17825     [14]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17826     web pages and the development of GCC are welcome on our developer
   17827     list at [15]gcc (a] gcc.gnu.org. All of [16]our lists have public
   17828     archives.
   17829 
   17830    Copyright (C) [17]Free Software Foundation, Inc. Verbatim copying and
   17831    distribution of this entire article is permitted in any medium,
   17832    provided this notice is preserved.
   17833 
   17834    These pages are [18]maintained by the GCC team. Last modified
   17835    2019-11-28[19].
   17836 
   17837 References
   17838 
   17839    1. http://www.netbsd.org/
   17840    2. http://gcc.gnu.org/news/reorder.html
   17841    3. http://gcc.gnu.org/news/ssa.html
   17842    4. http://gcc.gnu.org/news/null.html
   17843    5. http://gcc.gnu.org/news/unify.html
   17844    6. http://gcc.gnu.org/gcc-3.0/c++features.html
   17845    7. http://gcc.gnu.org/news/inlining.html
   17846    8. http://gcc.gnu.org/news/dependencies.html
   17847    9. http://gcc.gnu.org/c99status.html
   17848   10. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html
   17849   11. http://gcc.gnu.org/gcc-3.0/libgcc.html
   17850   12. http://gcc.gnu.org/gcc-2.95/features.html
   17851   13. https://gcc.gnu.org/onlinedocs/
   17852   14. mailto:gcc-help (a] gcc.gnu.org
   17853   15. mailto:gcc (a] gcc.gnu.org
   17854   16. https://gcc.gnu.org/lists.html
   17855   17. https://www.fsf.org/
   17856   18. https://gcc.gnu.org/about.html
   17857   19. http://validator.w3.org/check/referer
   17858 ======================================================================
   17859 http://gcc.gnu.org/gcc-3.0/caveats.html
   17860                                 GCC 3.0 Caveats
   17861 
   17862      * -fstrict-aliasing is now part of -O2 and higher optimization
   17863        levels. This allows the compiler to assume the strictest aliasing
   17864        rules applicable to the language being compiled. For C and C++,
   17865        this activates optimizations based on the type of expressions. This
   17866        optimization may thus break old, non-compliant code.
   17867      * Enumerations are now properly promoted to int in function
   17868        parameters and function returns. Normally this change is not
   17869        visible, but when using -fshort-enums this is an ABI change.
   17870      * The undocumented extension that allowed C programs to have a label
   17871        at the end of a compound statement has been deprecated and may be
   17872        removed in a future version. Programs that now generate a warning
   17873        about this may be fixed by adding a null statement (a single
   17874        semicolon) after the label.
   17875      * The poorly documented extension that allowed string constants in C,
   17876        C++ and Objective C to contain unescaped newlines has been
   17877        deprecated and may be removed in a future version. Programs using
   17878        this extension may be fixed in several ways: the bare newline may
   17879        be replaced by \n, or preceded by \n\, or string concatenation may
   17880        be used with the bare newline preceded by \n" and " placed at the
   17881        start of the next line.
   17882      * The Chill compiler is not included in GCC 3.0, because of the lack
   17883        of a volunteer to convert it to use garbage collection.
   17884      * Certain non-standard iostream methods from earlier versions of
   17885        libstdc++ are not included in libstdc++ v3, i.e. filebuf::attach,
   17886        ostream::form, and istream::gets.
   17887      * The new C++ ABI is not yet fully supported by current (as of
   17888        2001-07-01) releases and development versions of GDB, or any
   17889        earlier versions. There is a problem setting breakpoints by line
   17890        number, and other related issues that have been fixed in GCC 3.0
   17891        but not yet handled in GDB:
   17892        [1]https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html
   17893 
   17894 
   17895     For questions related to the use of GCC, please consult these web
   17896     pages and the [2]GCC manuals. If that fails, the
   17897     [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17898     web pages and the development of GCC are welcome on our developer
   17899     list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives.
   17900 
   17901    Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and
   17902    distribution of this entire article is permitted in any medium,
   17903    provided this notice is preserved.
   17904 
   17905    These pages are [7]maintained by the GCC team. Last modified
   17906    2019-11-28[8].
   17907 
   17908 References
   17909 
   17910    1. https://gcc.gnu.org/ml/gcc-bugs/2001-06/msg00421.html
   17911    2. https://gcc.gnu.org/onlinedocs/
   17912    3. mailto:gcc-help (a] gcc.gnu.org
   17913    4. mailto:gcc (a] gcc.gnu.org
   17914    5. https://gcc.gnu.org/lists.html
   17915    6. https://www.fsf.org/
   17916    7. https://gcc.gnu.org/about.html
   17917    8. http://validator.w3.org/check/referer
   17918 ======================================================================
   17919 http://gcc.gnu.org/gcc-2.95/index.html
   17920                                     GCC 2.95
   17921 
   17922    (This release series is no longer supported.)
   17923 
   17924    March 16, 2001: The GNU project and the GCC developers are pleased to
   17925    announce the release of GCC version 2.95.3.
   17926 
   17927 Release History
   17928 
   17929    GCC 2.95.3
   17930           March 16, 2001
   17931 
   17932    GCC 2.95.2
   17933           October 27, 1999
   17934 
   17935    GCC 2.95.1
   17936           August 19, 1999
   17937 
   17938    GCC 2.95
   17939           July 31, 1999. This is the first release of GCC since the April
   17940           1999 GCC/EGCS reunification and includes nearly a year's worth
   17941           of new development and bugfixes.
   17942 
   17943 References and Acknowledgements
   17944 
   17945    GCC used to stand for the GNU C Compiler, but since the compiler
   17946    supports several other languages aside from C, it now stands for the
   17947    GNU Compiler Collection.
   17948 
   17949    The whole suite has been extensively [1]regression tested and
   17950    [2]package tested. It should be reliable and suitable for widespread
   17951    use.
   17952 
   17953    The compiler has several new optimizations, new targets, new languages
   17954    and other new features. See the [3]new features page for a more
   17955    complete list of new features found in the GCC 2.95 releases.
   17956 
   17957    The sources include installation instructions in both HTML and
   17958    plaintext forms in the install directory in the distribution. However,
   17959    the most up to date installation instructions and [4]build/test status
   17960    are on the web pages. We will update those pages as new information
   17961    becomes available.
   17962 
   17963    The GCC developers would like to thank the numerous people that have
   17964    contributed new features, test results, bugfixes, etc to GCC. This
   17965    [5]amazing group of volunteers is what makes GCC successful.
   17966 
   17967    And finally, we can't in good conscience fail to mention some
   17968    [6]caveats to using GCC 2.95.
   17969 
   17970    Download GCC 2.95 from one of our many [7]mirror sites.
   17971 
   17972    For additional information about GCC please see the [8]GCC project web
   17973    server or contact the [9]GCC development mailing list.
   17974 
   17975 
   17976     For questions related to the use of GCC, please consult these web
   17977     pages and the [10]GCC manuals. If that fails, the
   17978     [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   17979     web pages and the development of GCC are welcome on our developer
   17980     list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public
   17981     archives.
   17982 
   17983    Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and
   17984    distribution of this entire article is permitted in any medium,
   17985    provided this notice is preserved.
   17986 
   17987    These pages are [15]maintained by the GCC team. Last modified
   17988    2019-11-28[16].
   17989 
   17990 References
   17991 
   17992    1. http://gcc.gnu.org/gcc-2.95/regress.html
   17993    2. http://gcc.gnu.org/gcc-2.95/othertest.html
   17994    3. http://gcc.gnu.org/gcc-2.95/features.html
   17995    4. http://gcc.gnu.org/gcc-2.95/buildstat.html
   17996    5. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   17997    6. http://gcc.gnu.org/gcc-2.95/caveats.html
   17998    7. http://gcc.gnu.org/mirrors.html
   17999    8. http://gcc.gnu.org/index.html
   18000    9. mailto:gcc (a] gcc.gnu.org
   18001   10. https://gcc.gnu.org/onlinedocs/
   18002   11. mailto:gcc-help (a] gcc.gnu.org
   18003   12. mailto:gcc (a] gcc.gnu.org
   18004   13. https://gcc.gnu.org/lists.html
   18005   14. https://www.fsf.org/
   18006   15. https://gcc.gnu.org/about.html
   18007   16. http://validator.w3.org/check/referer
   18008 ======================================================================
   18009 http://gcc.gnu.org/gcc-2.95/features.html
   18010                              GCC 2.95 New Features
   18011 
   18012      * General Optimizer Improvements:
   18013           + [1]Localized register spilling to improve speed and code
   18014             density especially on small register class machines.
   18015           + [2]Global CSE using lazy code motion algorithms.
   18016           + [3]Improved global constant/copy propagation.
   18017           + [4]Improved control flow graph analysis and manipulation.
   18018           + [5]Local dead store elimination.
   18019           + [6]Memory Load hoisting/store sinking in loops.
   18020           + [7]Type based alias analysis is enabled by default. Note this
   18021             feature will expose bugs in the Linux kernel. Please refer to
   18022             the FAQ (as shipped with GCC 2.95) for additional information
   18023             on this issue.
   18024           + Major revamp of GIV detection, combination and simplification
   18025             to improve loop performance.
   18026           + Major improvements to register allocation and reloading.
   18027      * New Languages and Language specific improvements
   18028           + [8]Many C++ improvements.
   18029           + [9]Many Fortran improvements.
   18030           + [10]Java front-end has been integrated. A [11]runtime library
   18031             is available separately.
   18032           + [12]ISO C99 support
   18033           + [13]Chill front-end and runtime has been integrated.
   18034           + Boehm garbage collector support in libobjc.
   18035           + More support for various pragmas which appear in vendor
   18036             include files
   18037      * New Targets and Target Specific Improvements
   18038           + [14]SPARC backend rewrite.
   18039           + -mschedule=8000 will optimize code for PA8000 class
   18040             processors; -mpa-risc-2-0 will generate code for PA2.0
   18041             processors
   18042           + Various micro-optimizations for the ia32 port. K6
   18043             optimizations
   18044           + Compiler will attempt to align doubles in the stack on the
   18045             ia32 port
   18046           + Alpha EV6 support
   18047           + PowerPC 750
   18048           + RS6000/PowerPC: -mcpu=401 was added as an alias for -mcpu=403.
   18049             -mcpu=e603e was added to do -mcpu=603e and -msoft-float.
   18050           + c3x, c4x
   18051           + HyperSPARC
   18052           + SparcLite86x
   18053           + sh4
   18054           + Support for new systems (OpenBSD, FreeBSD, UWIN, Interix,
   18055             arm-linux)
   18056           + vxWorks targets include support for vxWorks threads
   18057           + StrongARM 110 and ARM9 support added. ARM Scheduling
   18058             parameters rewritten.
   18059           + Various changes to the MIPS port to avoid assembler macros,
   18060             which in turn improves performance
   18061           + Various performance improvements to the i960 port.
   18062           + Major rewrite of ns32k port
   18063      * Other significant improvements
   18064           + [15]Ability to dump cfg information and display it using vcg.
   18065           + The new faster scheme for fixing vendor header files is
   18066             enabled by default.
   18067           + Experimental internationalization support.
   18068           + multibyte character support
   18069           + Some compile-time speedups for pathological problems
   18070           + Better support for complex types
   18071      * Plus the usual mountain of bugfixes
   18072      * Core compiler is based on the gcc2 development tree from Sept 30,
   18073        1998, so we have all of the [16]features found in GCC 2.8.
   18074 
   18075 Additional Changes in GCC 2.95.1
   18076 
   18077      * Generic bugfixes and improvements
   18078           + Various documentation fixes related to the GCC/EGCS merger.
   18079           + Fix memory management bug which could lead to spurious aborts,
   18080             core dumps or random parsing errors in the compiler.
   18081           + Fix a couple bugs in the dwarf1 and dwarf2 debug record
   18082             support.
   18083           + Fix infinite loop in the CSE optimizer.
   18084           + Avoid undefined behavior in compiler FP emulation code
   18085           + Fix install problem when prefix is overridden on the make
   18086             install command.
   18087           + Fix problem with unwanted installation of assert.h on some
   18088             systems.
   18089           + Fix problem with finding the wrong assembler in a single tree
   18090             build.
   18091           + Avoid increasing the known alignment of a register that is
   18092             already known to be a pointer.
   18093      * Platform specific bugfixes and improvements
   18094           + Codegen bugfix for prologue/epilogue for cpu32 target.
   18095           + Fix long long code generation bug for the Coldfire target.
   18096           + Fix various aborts in the SH compiler.
   18097           + Fix bugs in libgcc support library for the SH.
   18098           + Fix alpha ev6 code generation bug.
   18099           + Fix problems with EXIT_SUCCESS/EXIT_FAILURE redefinitions on
   18100             AIX platforms.
   18101           + Fix -fpic code generation bug for rs6000/ppc svr4 targets.
   18102           + Fix varargs/stdarg code generation bug for rs6000/ppc svr4
   18103             targets.
   18104           + Fix weak symbol handling for rs6000/ppc svr4 targets.
   18105           + Fix various problems with 64bit code generation for the
   18106             rs6000/ppc port.
   18107           + Fix codegen bug which caused tetex to be mis-compiled on the
   18108             x86.
   18109           + Fix compiler abort in new cfg code exposed by x86 port.
   18110           + Fix out of range array reference in code convert flat
   18111             registers to the x87 stacked FP register file.
   18112           + Fix minor vxworks configuration bug.
   18113           + Fix return type of bsearch for SunOS 4.x.
   18114      * Language & Runtime specific fixes.
   18115           + The G++ signature extension has been deprecated. It will be
   18116             removed in the next major release of G++. Use of signatures
   18117             will result in a warning from the compiler.
   18118           + Several bugs relating to templates and namespaces were fixed.
   18119           + A bug that caused crashes when combining templates with -g on
   18120             DWARF1 platforms was fixed.
   18121           + Pointers-to-members, virtual functions, and multiple
   18122             inheritance should now work together correctly.
   18123           + Some code-generation bugs relating to function try blocks were
   18124             fixed.
   18125           + G++ is a little bit more lenient with certain archaic
   18126             constructs than in GCC 2.95.
   18127           + Fix to prevent shared library version #s from bring truncated
   18128             to 1 digit
   18129           + Fix missing std:: in the libstdc++ library.
   18130           + Fix stream locking problems in libio.
   18131           + Fix problem in java compiler driver.
   18132 
   18133 Additional Changes in GCC 2.95.2
   18134 
   18135    The -fstrict-aliasing is not enabled by default for GCC 2.95.2. While
   18136    the optimizations performed by -fstrict-aliasing are valid according to
   18137    the C and C++ standards, the optimization have caused some problems,
   18138    particularly with old non-conforming code.
   18139 
   18140    The GCC developers are experimenting with ways to warn users about code
   18141    which violates the C/C++ standards, but those warnings are not ready
   18142    for widespread use at this time. Rather than wait for those warnings
   18143    the GCC developers have chosen to disable -fstrict-aliasing by default
   18144    for the GCC 2.95.2 release.
   18145 
   18146    We strongly encourage developers to find and fix code which violates
   18147    the C/C++ standards as -fstrict-aliasing may be enabled by default in
   18148    future releases. Use the option -fstrict-aliasing to re-enable these
   18149    optimizations.
   18150      * Generic bugfixes and improvements
   18151           + Fix incorrectly optimized memory reference in global common
   18152             subexpression elimination (GCSE) optimization pass.
   18153           + Fix code generation bug in regmove.c in which it could
   18154             incorrectly change a "const" value.
   18155           + Fix bug in optimization of conditionals involving volatile
   18156             memory references.
   18157           + Avoid over-allocation of stack space for some procedures.
   18158           + Fixed bug in the compiler which caused incorrect optimization
   18159             of an obscure series of bit manipulations, shifts and
   18160             arithmetic.
   18161           + Fixed register allocator bug which caused teTeX to be
   18162             mis-compiled on SPARC targets.
   18163           + Avoid incorrect optimization of degenerate case statements for
   18164             certain targets such as the ARM.
   18165           + Fix out of range memory reference in the jump optimizer.
   18166           + Avoid dereferencing null pointer in fix-header.
   18167           + Fix test for GCC specific features so that it is possible to
   18168             bootstrap with gcc-2.6.2 and older versions of GCC.
   18169           + Fix typo in scheduler which could potentially cause out of
   18170             range memory accesses.
   18171           + Avoid incorrect loop reversal which caused incorrect code for
   18172             certain loops on PowerPC targets.
   18173           + Avoid incorrect optimization of switch statements on certain
   18174             targets (for example the ARM).
   18175      * Platform specific bugfixes and improvements
   18176           + Work around bug in Sun V5.0 compilers which caused bootstrap
   18177             comparison failures on SPARC targets.
   18178           + Fix SPARC backend bug which caused aborts in final.c.
   18179           + Fix sparc-hal-solaris2* configuration fragments.
   18180           + Fix bug in sparc block profiling.
   18181           + Fix obscure code generation bug for the PARISC targets.
   18182           + Define __STDC_EXT__ for HPUX configurations.
   18183           + Various POWERPC64 code generation bugfixes.
   18184           + Fix abort for PPC targets using ELF (ex GNU/Linux).
   18185           + Fix collect2 problems for AIX targets.
   18186           + Correct handling of .file directive for PPC targets.
   18187           + Fix bug in fix_trunc x86 patterns.
   18188           + Fix x86 port to correctly pop the FP stack for functions that
   18189             return structures in memory.
   18190           + Fix minor bug in strlen x86 pattern.
   18191           + Use stabs debugging instead of dwarf1 for x86-solaris targets.
   18192           + Fix template repository code to handle leading underscore in
   18193             mangled names.
   18194           + Fix weak/weak alias support for OpenBSD.
   18195           + GNU/Linux for the ARM has C++ compatible include files.
   18196      * Language & Runtime specific fixes.
   18197           + Fix handling of constructor attribute in the C front-end which
   18198             caused problems building the Chill runtime library on some
   18199             targets.
   18200           + Fix minor problem merging type qualifiers in the C front-end.
   18201           + Fix aliasing bug for pointers and references (C/C++).
   18202           + Fix incorrect "non-constant initializer bug" when -traditional
   18203             or -fwritable-strings is enabled.
   18204           + Fix build error for Chill front-end on SunOS.
   18205           + Do not complain about duplicate instantiations when using
   18206             -frepo (C++).
   18207           + Fix array bounds handling in C++ front-end which caused
   18208             problems with dwarf debugging information in some
   18209             circumstances.
   18210           + Fix minor namespace problem.
   18211           + Fix problem linking java programs.
   18212 
   18213 Additional Changes in GCC 2.95.3
   18214 
   18215      * Generic bugfixes and improvements
   18216           + Fix numerous problems that caused incorrect optimization in
   18217             the register reloading code.
   18218           + Fix numerous problems that caused incorrect optimization in
   18219             the loop optimizer.
   18220           + Fix aborts in the functions build_insn_chain and scan_loops
   18221             under some circumstances.
   18222           + Fix an alias analysis bug.
   18223           + Fix an infinite compilation bug in the combiner.
   18224           + A few problems with complex number support have been fixed.
   18225           + It is no longer possible for gcc to act as a fork bomb when
   18226             installed incorrectly.
   18227           + The -fpack-struct option should be recognized now.
   18228           + Fixed a bug that caused incorrect code to be generated due to
   18229             a lost stack adjustment.
   18230      * Platform specific bugfixes and improvements
   18231           + Support building ARM toolchains hosted on Windows.
   18232           + Fix attribute calculations in ARM toolchains.
   18233           + arm-linux support has been improved.
   18234           + Fix a PIC failure on sparc targets.
   18235           + On ix86 targets, the regparm attribute should now work
   18236             reliably.
   18237           + Several updates for the h8300 port.
   18238           + Fix problem building libio with glibc 2.2.
   18239 
   18240 
   18241     For questions related to the use of GCC, please consult these web
   18242     pages and the [17]GCC manuals. If that fails, the
   18243     [18]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18244     web pages and the development of GCC are welcome on our developer
   18245     list at [19]gcc (a] gcc.gnu.org. All of [20]our lists have public
   18246     archives.
   18247 
   18248    Copyright (C) [21]Free Software Foundation, Inc. Verbatim copying and
   18249    distribution of this entire article is permitted in any medium,
   18250    provided this notice is preserved.
   18251 
   18252    These pages are [22]maintained by the GCC team. Last modified
   18253    2019-11-28[23].
   18254 
   18255 References
   18256 
   18257    1. http://gcc.gnu.org/news/spill.html
   18258    2. http://gcc.gnu.org/news/lcm.html
   18259    3. http://gcc.gnu.org/news/cprop.html
   18260    4. http://gcc.gnu.org/news/cfg.html
   18261    5. http://gcc.gnu.org/news/dse.html
   18262    6. http://gcc.gnu.org/news/hoist.html
   18263    7. http://gcc.gnu.org/news/alias.html
   18264    8. http://gcc.gnu.org/gcc-2.95/c++features.html
   18265    9. https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/News.html
   18266   10. http://gcc.gnu.org/news/gcj-announce.txt
   18267   11. http://gcc.gnu.org/news/javaannounce.html
   18268   12. http://gcc.gnu.org/c99status.html
   18269   13. http://gcc.gnu.org/news/chill.html
   18270   14. http://gcc.gnu.org/news/sparc.html
   18271   15. http://gcc.gnu.org/news/egcs-vcg.html
   18272   16. http://gcc.gnu.org/egcs-1.0/features-2.8.html
   18273   17. https://gcc.gnu.org/onlinedocs/
   18274   18. mailto:gcc-help (a] gcc.gnu.org
   18275   19. mailto:gcc (a] gcc.gnu.org
   18276   20. https://gcc.gnu.org/lists.html
   18277   21. https://www.fsf.org/
   18278   22. https://gcc.gnu.org/about.html
   18279   23. http://validator.w3.org/check/referer
   18280 ======================================================================
   18281 http://gcc.gnu.org/gcc-2.95/caveats.html
   18282                                 GCC 2.95 Caveats
   18283 
   18284      * GCC 2.95 will issue an error for invalid asm statements that had
   18285        been silently accepted by earlier versions of the compiler. This is
   18286        particularly noticeable when compiling older versions of the Linux
   18287        kernel (2.0.xx). Please refer to the FAQ (as shipped with GCC 2.95)
   18288        for more information on this issue.
   18289      * GCC 2.95 implements type based alias analysis to disambiguate
   18290        memory references. Some programs, particularly the Linux kernel
   18291        violate ANSI/ISO aliasing rules and therefore may not operate
   18292        correctly when compiled with GCC 2.95. Please refer to the FAQ (as
   18293        shipped with GCC 2.95) for more information on this issue.
   18294      * GCC 2.95 has a known bug in its handling of complex variables for
   18295        64bit targets. Instead of silently generating incorrect code, GCC
   18296        2.95 will issue a fatal error for situations it can not handle.
   18297        This primarily affects the Fortran community as Fortran makes more
   18298        use of complex variables than C or C++.
   18299      * GCC 2.95 has an integrated libstdc++, but does not have an
   18300        integrated libg++. Furthermore old libg++ releases will not work
   18301        with GCC 2.95. You can retrieve a recent copy of libg++ from the
   18302        [1]GCC ftp server.
   18303        Note most C++ programs only need libstdc++.
   18304      * Exception handling may not work with shared libraries, particularly
   18305        on alphas, hppas, rs6000/powerpc and mips based platforms.
   18306        Exception handling is known to work on x86 GNU/Linux platforms with
   18307        shared libraries.
   18308      * In general, GCC 2.95 is more rigorous about rejecting invalid C++
   18309        code or deprecated C++ constructs than G++ 2.7, G++ 2.8, EGCS 1.0,
   18310        or EGCS 1.1. As a result it may be necessary to fix C++ code before
   18311        it will compile with GCC 2.95.
   18312      * G++ is also converting toward the ISO C++ standard; as a result
   18313        code which was previously valid (and thus accepted by other
   18314        compilers and older versions of g++) may no longer be accepted. The
   18315        flag -fpermissive may allow some non-conforming code to compile
   18316        with GCC 2.95.
   18317      * GCC 2.95 compiled C++ code is not binary compatible with EGCS
   18318        1.1.x, EGCS 1.0.x or GCC 2.8.x.
   18319      * GCC 2.95 does not have changes from the GCC 2.8 tree that were made
   18320        between Sept 30, 1998 and April 30, 1999 (the official end of the
   18321        GCC 2.8 project). Future GCC releases will include all the changes
   18322        from the defunct GCC 2.8 sources.
   18323 
   18324 
   18325     For questions related to the use of GCC, please consult these web
   18326     pages and the [2]GCC manuals. If that fails, the
   18327     [3]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18328     web pages and the development of GCC are welcome on our developer
   18329     list at [4]gcc (a] gcc.gnu.org. All of [5]our lists have public archives.
   18330 
   18331    Copyright (C) [6]Free Software Foundation, Inc. Verbatim copying and
   18332    distribution of this entire article is permitted in any medium,
   18333    provided this notice is preserved.
   18334 
   18335    These pages are [7]maintained by the GCC team. Last modified
   18336    2019-11-28[8].
   18337 
   18338 References
   18339 
   18340    1. ftp://gcc.gnu.org/pub/gcc/infrastructure/libg++-2.8.1.3.tar.gz
   18341    2. https://gcc.gnu.org/onlinedocs/
   18342    3. mailto:gcc-help (a] gcc.gnu.org
   18343    4. mailto:gcc (a] gcc.gnu.org
   18344    5. https://gcc.gnu.org/lists.html
   18345    6. https://www.fsf.org/
   18346    7. https://gcc.gnu.org/about.html
   18347    8. http://validator.w3.org/check/referer
   18348 ======================================================================
   18349 http://gcc.gnu.org/egcs-1.1/index.html
   18350                                     EGCS 1.1
   18351 
   18352    September 3, 1998: We are pleased to announce the release of EGCS 1.1.
   18353    December 1, 1998: We are pleased to announce the release of EGCS 1.1.1.
   18354    March 15, 1999: We are pleased to announce the release of EGCS 1.1.2.
   18355 
   18356    EGCS is a free software project to further the development of the GNU
   18357    compilers using an open development environment.
   18358 
   18359    EGCS 1.1 is a major new release of the EGCS compiler system. It has
   18360    been [1]extensively tested and is believed to be stable and suitable
   18361    for widespread use.
   18362 
   18363    EGCS 1.1 is based on an June 6, 1998 snapshot of the GCC 2.8
   18364    development sources; it contains all of the new features found in GCC
   18365    2.8.1 as well as all new development from GCC up to June 6, 1998.
   18366 
   18367    EGCS 1.1 also contains many improvements and features not found in GCC
   18368    or in older versions of EGCS:
   18369      * Global common subexpression elimination and global constant/copy
   18370        propagation (aka [2]gcse)
   18371      * Ongoing improvements to the [3]alias analysis support to allow for
   18372        better optimizations throughout the compiler.
   18373      * Vastly improved [4]C++ compiler and integrated C++ runtime
   18374        libraries.
   18375      * Fixes for the /tmp symlink race security problems.
   18376      * New targets including mips16, arm-thumb and 64 bit PowerPC.
   18377      * Improvements to GNU Fortran (g77) compiler and runtime library made
   18378        since g77 version 0.5.23.
   18379 
   18380    See the [5]new features page for a more complete list of new features
   18381    found in EGCS 1.1 releases.
   18382 
   18383    EGCS 1.1.1 is a minor update to fix several serious problems in EGCS
   18384    1.1:
   18385      * General improvements and fixes
   18386           + Avoid some stack overflows when compiling large functions.
   18387           + Avoid incorrect loop invariant code motions.
   18388           + Fix some core dumps on Linux kernel code.
   18389           + Bring back the imake -Di386 and friends fix from EGCS 1.0.2.
   18390           + Fix code generation problem in gcse.
   18391           + Various documentation related fixes.
   18392      * g++/libstdc++ improvements and fixes
   18393           + MT safe EH fix for setjmp/longjmp based exception handling.
   18394           + Fix a few bad interactions between optimization and exception
   18395             handling.
   18396           + Fixes for demangling of template names starting with "__".
   18397           + Fix a bug that would fail to run destructors in some cases
   18398             with -O2.
   18399           + Fix 'new' of classes with virtual bases.
   18400           + Fix crash building Qt on the Alpha.
   18401           + Fix failure compiling WIFEXITED macro on GNU/Linux.
   18402           + Fix some -frepo failures.
   18403      * g77 and libf2c improvements and fixes
   18404           + Various documentation fixes.
   18405           + Avoid compiler crash on RAND intrinsic.
   18406           + Fix minor bugs in makefiles exposed by BSD make programs.
   18407           + Define _XOPEN_SOURCE for libI77 build to avoid potential
   18408             problems on some 64-bit systems.
   18409           + Fix problem with implicit endfile on rewind.
   18410           + Fix spurious recursive I/O errors.
   18411      * platform specific improvements and fixes
   18412           + Match all versions of UnixWare7.
   18413           + Do not assume x86 SVR4 or UnixWare targets can handle stabs.
   18414           + Fix PPC/RS6000 LEGITIMIZE_ADDRESS macro and bug in conversion
   18415             from unsigned ints to double precision floats.
   18416           + Fix ARM ABI issue with NetBSD.
   18417           + Fix a few arm code generation bugs.
   18418           + Fixincludes will fix additional broken SCO OpenServer header
   18419             files.
   18420           + Fix a m68k backend bug which caused invalid offsets in reg+d
   18421             addresses.
   18422           + Fix problems with 64bit AIX 4.3 support.
   18423           + Fix handling of long longs for varargs/stdarg functions on the
   18424             ppc.
   18425           + Minor fixes to CPP predefines for Windows.
   18426           + Fix code generation problems with gpr<->fpr copies for 64bit
   18427             ppc.
   18428           + Fix a few coldfire code generation bugs.
   18429           + Fix some more header file problems on SunOS 4.x.
   18430           + Fix assert.h handling for RTEMS.
   18431           + Fix Windows handling of TREE_SYMBOL_REFERENCED.
   18432           + Fix x86 compiler abort in reg-stack pass.
   18433           + Fix cygwin/windows problem with section attributes.
   18434           + Fix Alpha code generation problem exposed by SMP Linux
   18435             kernels.
   18436           + Fix typo in m68k 32->64bit integer conversion.
   18437           + Make sure target libraries build with -fPIC for PPC & Alpha
   18438             targets.
   18439 
   18440    EGCS 1.1.2 is a minor update to fix several serious problems in EGCS
   18441    1.1.1:
   18442      * General improvements and fixes
   18443           + Fix bug in loop optimizer which caused the SPARC (and
   18444             potentially other) ports to segfault.
   18445           + Fix infinite recursion in alias analysis and combiner code.
   18446           + Fix bug in regclass preferencing.
   18447           + Fix incorrect loop reversal which caused incorrect code to be
   18448             generated for several targets.
   18449           + Fix return value for builtin memcpy.
   18450           + Reduce compile time for certain loops which exposed quadratic
   18451             behavior in the loop optimizer.
   18452           + Fix bug which caused volatile memory to be written multiple
   18453             times when only one write was needed/desired.
   18454           + Fix compiler abort in caller-save.c
   18455           + Fix combiner bug which caused incorrect code generation for
   18456             certain division by constant operations.
   18457           + Fix incorrect code generation due to a bug in range check
   18458             optimizations.
   18459           + Fix incorrect code generation due to mis-handling of clobbered
   18460             values in CSE.
   18461           + Fix compiler abort/segfault due to incorrect register
   18462             splitting when unrolling loops.
   18463           + Fix code generation involving autoincremented addresses with
   18464             ternary operators.
   18465           + Work around bug in the scheduler which caused qt to be
   18466             mis-compiled on some platforms.
   18467           + Fix code generation problems with -fshort-enums.
   18468           + Tighten security for temporary files.
   18469           + Improve compile time for codes which make heavy use of
   18470             overloaded functions.
   18471           + Fix multiply defined constructor/destructor symbol problems.
   18472           + Avoid setting bogus RPATH environment variable during
   18473             bootstrap.
   18474           + Avoid GNU-make dependencies in the texinfo subdir.
   18475           + Install CPP wrapper script in $(prefix)/bin if --enable-cpp.
   18476             --enable-cpp=<dirname> can be used to specify an additional
   18477             install directory for the cpp wrapper script.
   18478           + Fix CSE bug which caused incorrect label-label refs to appear
   18479             on some platforms.
   18480           + Avoid linking in EH routines from libgcc if they are not
   18481             needed.
   18482           + Avoid obscure bug in aliasing code.
   18483           + Fix bug in weak symbol handling.
   18484      * Platform-specific improvements and fixes
   18485           + Fix detection of PPro/PII on Unixware 7.
   18486           + Fix compiler segfault when building spec99 and other programs
   18487             for SPARC targets.
   18488           + Fix code-generation bugs for integer and floating point
   18489             conditional move instructions on the PPro/PII.
   18490           + Use fixincludes to fix byteorder problems on i?86-*-sysv.
   18491           + Fix build failure for the arc port.
   18492           + Fix floating point format configuration for i?86-gnu port.
   18493           + Fix problems with hppa1.0-hp-hpux10.20 configuration when
   18494             threads are enabled.
   18495           + Fix coldfire code generation bugs.
   18496           + Fix "unrecognized insn" problems for Alpha and PPC ports.
   18497           + Fix h8/300 code generation problem with floating point values
   18498             in memory.
   18499           + Fix unrecognized insn problems for the m68k port.
   18500           + Fix namespace-pollution problem for the x86 port.
   18501           + Fix problems with old assembler on x86 NeXT systems.
   18502           + Fix PIC code-generation problems for the SPARC port.
   18503           + Fix minor bug with LONG_CALLS in PowerPC SVR4 support.
   18504           + Fix minor ISO namespace violation in Alpha varargs/stdarg
   18505             support.
   18506           + Fix incorrect "braf" instruction usage for the SH port.
   18507           + Fix minor bug in va-sh which prevented its use with -ansi.
   18508           + Fix problems recognizing and supporting FreeBSD.
   18509           + Handle OpenBSD systems correctly.
   18510           + Minor fixincludes fix for Digital UNIX 4.0B.
   18511           + Fix problems with ctors/dtors in SCO shared libraries.
   18512           + Abort instead of generating incorrect code for PPro/PII
   18513             floating point conditional moves.
   18514           + Avoid multiply defined symbols on GNU/Linux systems using
   18515             libc-5.4.xx.
   18516           + Fix abort in alpha compiler.
   18517      * Fortran-specific fixes
   18518           + Fix the IDate intrinsic (VXT) (in libg2c) so the returned year
   18519             is in the documented, non-Y2K-compliant range of 0-99, instead
   18520             of being returned as 100 in the year 2000.
   18521           + Fix the `Date_and_Time' intrinsic (in libg2c) to return the
   18522             milliseconds value properly in Values(8).
   18523           + Fix the `LStat' intrinsic (in libg2c) to return device-ID
   18524             information properly in SArray(7).
   18525 
   18526    Each release includes installation instructions in both HTML and
   18527    plaintext forms (see the INSTALL directory in the toplevel directory of
   18528    the distribution). However, we also keep the most up to date
   18529    installation instructions and [6]build/test status on our web page. We
   18530    will update those pages as new information becomes available.
   18531 
   18532    The EGCS project would like to thank the numerous people that have
   18533    contributed new features, test results, bugfixes, etc. This [7]amazing
   18534    group of volunteers is what makes EGCS successful.
   18535 
   18536    And finally, we can't in good conscience fail to mention some
   18537    [8]caveats to using EGCS 1.1.
   18538 
   18539    Download EGCS from egcs.cygnus.com (USA California).
   18540 
   18541    The EGCS 1.1 release is also available on many mirror sites.
   18542    [9]Goto mirror list to find a closer site.
   18543 
   18544 
   18545     For questions related to the use of GCC, please consult these web
   18546     pages and the [10]GCC manuals. If that fails, the
   18547     [11]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18548     web pages and the development of GCC are welcome on our developer
   18549     list at [12]gcc (a] gcc.gnu.org. All of [13]our lists have public
   18550     archives.
   18551 
   18552    Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and
   18553    distribution of this entire article is permitted in any medium,
   18554    provided this notice is preserved.
   18555 
   18556    These pages are [15]maintained by the GCC team. Last modified
   18557    2019-11-28[16].
   18558 
   18559 References
   18560 
   18561    1. http://gcc.gnu.org/egcs-1.1/egcs-1.1-test.html
   18562    2. http://gcc.gnu.org/news/gcse.html
   18563    3. http://gcc.gnu.org/news/alias.html
   18564    4. http://gcc.gnu.org/egcs-1.1/c++features.html
   18565    5. http://gcc.gnu.org/egcs-1.1/features.html
   18566    6. http://gcc.gnu.org/egcs-1.1/buildstat.html
   18567    7. https://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   18568    8. http://gcc.gnu.org/egcs-1.1/caveats.html
   18569    9. http://gcc.gnu.org/mirrors.html
   18570   10. https://gcc.gnu.org/onlinedocs/
   18571   11. mailto:gcc-help (a] gcc.gnu.org
   18572   12. mailto:gcc (a] gcc.gnu.org
   18573   13. https://gcc.gnu.org/lists.html
   18574   14. https://www.fsf.org/
   18575   15. https://gcc.gnu.org/about.html
   18576   16. http://validator.w3.org/check/referer
   18577 ======================================================================
   18578 http://gcc.gnu.org/egcs-1.1/features.html
   18579                              EGCS 1.1 new features
   18580 
   18581      * Integrated GNU Fortran (g77) compiler and runtime library with
   18582        improvements, based on g77 version 0.5.23.
   18583      * Vast improvements in the C++ compiler; so many they have [1]page of
   18584        their own!
   18585      * Compiler implements [2]global common subexpression elimination and
   18586        global copy/constant propagation.
   18587      * More major improvements in the [3]alias analysis code.
   18588      * More major improvements in the exception handling code to improve
   18589        performance, lower static overhead and provide the infrastructure
   18590        for future improvements.
   18591      * The infamous /tmp symlink race security problems have been fixed.
   18592      * The regmove optimization pass has been nearly completely rewritten
   18593        to improve performance of generated code.
   18594      * The compiler now recomputes register usage information before local
   18595        register allocation. By providing more accurate information to the
   18596        priority based allocator, we get better register allocation.
   18597      * The register reloading phase of the compiler optimizes spill code
   18598        much better than in previous releases.
   18599      * Some bad interactions between the register allocator and
   18600        instruction scheduler have been fixed, resulting in much better
   18601        code for certain programs. Additionally, we have tuned the
   18602        scheduler in various ways to improve performance of generated code
   18603        for some architectures.
   18604      * The compiler's branch shortening algorithms have been significantly
   18605        improved to work better on targets which align jump targets.
   18606      * The compiler now supports -Os to prefer optimizing for code space
   18607        over optimizing for code speed.
   18608      * The compiler will now totally eliminate library calls which compute
   18609        constant values. This primarily helps targets with no integer
   18610        div/mul support and targets without floating point support.
   18611      * The compiler now supports an extensive "--help" option.
   18612      * cpplib has been greatly improved and may be suitable for limited
   18613        use.
   18614      * Memory footprint for the compiler has been significantly reduced
   18615        for some pathological cases.
   18616      * The time to build EGCS has been improved for certain targets
   18617        (particularly the alpha and mips platforms).
   18618      * Many infrastructure improvements throughout the compiler, plus the
   18619        usual mountain of bugfixes and minor improvements.
   18620      * Target dependent improvements:
   18621           + SPARC port now includes V8 plus and V9 support as well as
   18622             performance tuning for Ultra class machines. The SPARC port
   18623             now uses the Haifa scheduler.
   18624           + Alpha port has been tuned for the EV6 processor and has an
   18625             optimized expansion of memcpy/bzero. The Alpha port now uses
   18626             the Haifa scheduler.
   18627           + RS6000/PowerPC: support for the Power64 architecture and AIX
   18628             4.3. The RS6000/PowerPC port now uses the Haifa scheduler.
   18629           + x86: Alignment of static store data and jump targets is per
   18630             Intel recommendations now. Various improvements throughout the
   18631             x86 port to improve performance on Pentium processors
   18632             (including improved epilogue sequences for Pentium chips and
   18633             backend improvements which should help register allocation on
   18634             all x86 variants. Conditional move support has been fixed and
   18635             enabled for PPro processors. The x86 port also better supports
   18636             64bit operations now. Unixware 7, a System V Release 5 target,
   18637             is now supported and SCO OpenServer targets can support GAS.
   18638           + MIPS has improved multiply/multiply-add support and now
   18639             includes mips16 ISA support.
   18640           + M68k has many micro-optimizations and Coldfire fixes.
   18641      * Core compiler is based on the GCC development tree from June 9,
   18642        1998, so we have all of the [4]features found in GCC 2.8.
   18643 
   18644 
   18645     For questions related to the use of GCC, please consult these web
   18646     pages and the [5]GCC manuals. If that fails, the
   18647     [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18648     web pages and the development of GCC are welcome on our developer
   18649     list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives.
   18650 
   18651    Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and
   18652    distribution of this entire article is permitted in any medium,
   18653    provided this notice is preserved.
   18654 
   18655    These pages are [10]maintained by the GCC team. Last modified
   18656    2019-11-28[11].
   18657 
   18658 References
   18659 
   18660    1. http://gcc.gnu.org/egcs-1.1/c++features.html
   18661    2. http://gcc.gnu.org/news/gcse.html
   18662    3. http://gcc.gnu.org/news/alias.html
   18663    4. http://gcc.gnu.org/egcs-1.0/features-2.8.html
   18664    5. https://gcc.gnu.org/onlinedocs/
   18665    6. mailto:gcc-help (a] gcc.gnu.org
   18666    7. mailto:gcc (a] gcc.gnu.org
   18667    8. https://gcc.gnu.org/lists.html
   18668    9. https://www.fsf.org/
   18669   10. https://gcc.gnu.org/about.html
   18670   11. http://validator.w3.org/check/referer
   18671 ======================================================================
   18672 http://gcc.gnu.org/egcs-1.1/caveats.html
   18673                                 EGCS 1.1 Caveats
   18674 
   18675      * EGCS has an integrated libstdc++, but does not have an integrated
   18676        libg++. Furthermore old libg++ releases will not work with EGCS; HJ
   18677        Lu has made a libg++-2.8.1.2 snapshot available which may work with
   18678        EGCS.
   18679        Note most C++ programs only need libstdc++.
   18680      * Exception handling may not work with shared libraries, particularly
   18681        on alphas, hppas, rs6000/powerpc and mips based platforms.
   18682        Exception handling is known to work on x86-linux platforms with
   18683        shared libraries.
   18684      * Some versions of the Linux kernel have bugs which prevent them from
   18685        being compiled or from running when compiled by EGCS. See the FAQ
   18686        (as shipped with EGCS 1.1) for additional information.
   18687      * In general, EGCS is more rigorous about rejecting invalid C++ code
   18688        or deprecated C++ constructs than g++-2.7, g++-2.8 or EGCS 1.0. As
   18689        a result it may be necessary to fix C++ code before it will compile
   18690        with EGCS.
   18691      * G++ is also converting toward the ISO C++ standard; as a result
   18692        code which was previously valid (and thus accepted by other
   18693        compilers and older versions of g++) may no longer be accepted.
   18694      * EGCS 1.1 compiled C++ code is not binary compatible with EGCS 1.0.x
   18695        or GCC 2.8.x due to changes necessary to support thread safe
   18696        exception handling.
   18697 
   18698 
   18699     For questions related to the use of GCC, please consult these web
   18700     pages and the [1]GCC manuals. If that fails, the
   18701     [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18702     web pages and the development of GCC are welcome on our developer
   18703     list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives.
   18704 
   18705    Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and
   18706    distribution of this entire article is permitted in any medium,
   18707    provided this notice is preserved.
   18708 
   18709    These pages are [6]maintained by the GCC team. Last modified
   18710    2019-11-28[7].
   18711 
   18712 References
   18713 
   18714    1. https://gcc.gnu.org/onlinedocs/
   18715    2. mailto:gcc-help (a] gcc.gnu.org
   18716    3. mailto:gcc (a] gcc.gnu.org
   18717    4. https://gcc.gnu.org/lists.html
   18718    5. https://www.fsf.org/
   18719    6. https://gcc.gnu.org/about.html
   18720    7. http://validator.w3.org/check/referer
   18721 ======================================================================
   18722 http://gcc.gnu.org/egcs-1.0/index.html
   18723                                     EGCS 1.0
   18724 
   18725    December 3, 1997: We are pleased to announce the release of EGCS 1.0.
   18726    January 6, 1998: We are pleased to announce the release of EGCS 1.0.1.
   18727    March 16, 1998: We are pleased to announce the release of EGCS 1.0.2.
   18728    May 15, 1998 We are pleased to announce the release of EGCS 1.0.3.
   18729 
   18730    EGCS is a collaborative effort involving several groups of hackers
   18731    using an open development model to accelerate development and testing
   18732    of GNU compilers and runtime libraries.
   18733 
   18734    An important goal of EGCS is to allow wide scale testing of
   18735    experimental features and optimizations; therefore, EGCS contains some
   18736    features and optimizations which are still under development. However,
   18737    EGCS has been carefully tested and should be comparable in quality to
   18738    most GCC releases.
   18739 
   18740    EGCS 1.0 is based on an August 2, 1997 snapshot of the GCC 2.8
   18741    development sources; it contains nearly all of the new features found
   18742    in GCC 2.8.
   18743 
   18744    EGCS 1.0 also contains many improvements and features not found in GCC
   18745    2.7 and even the GCC 2.8 series (which was released after the original
   18746    EGCS 1.0 release).
   18747      * Integrated C++ runtime libraries, including support for most major
   18748        GNU/Linux systems!
   18749      * The integrated libstdc++ library includes a verbatim copy of SGI's
   18750        STL release.
   18751      * Integrated GNU Fortran compiler.
   18752      * New instruction scheduler.
   18753      * New alias analysis code.
   18754 
   18755    See the [1]new features page for a more complete list of new features.
   18756 
   18757    EGCS 1.0.1 is a minor update to the EGCS 1.0 compiler to fix a few
   18758    critical bugs and add support for Red Hat 5.0 Linux. Changes since the
   18759    EGCS 1.0 release:
   18760      * Add support for Red Hat 5.0 Linux and better support for Linux
   18761        systems using glibc2.
   18762        Many programs failed to link when compiled with EGCS 1.0 on Red Hat
   18763        5.0 or on systems with newer versions of glibc2. EGCS 1.0.1 should
   18764        fix these problems.
   18765      * Compatibility with both EGCS 1.0 and GCC 2.8 libgcc exception
   18766        handling interfaces.
   18767        To avoid future compatibility problems, we strongly urge anyone who
   18768        is planning on distributing shared libraries that contain C++ code
   18769        to upgrade to EGCS 1.0.1 first.
   18770        Soon after EGCS 1.0 was released, the GCC developers made some
   18771        incompatible changes in libgcc's exception handling interfaces.
   18772        These changes were needed to solve problems on some platforms. This
   18773        means that GCC 2.8.0, when released, will not be seamlessly
   18774        compatible with shared libraries built by EGCS 1.0. The reason is
   18775        that the libgcc.a in GCC 2.8.0 will not contain a function needed
   18776        by the old interface.
   18777        The result of this is that there may be compatibility problems with
   18778        shared libraries built by EGCS 1.0 when used with GCC 2.8.0.
   18779        With EGCS 1.0.1, generated code uses the new (GCC 2.8.0) interface,
   18780        and libgcc.a has the support routines for both the old and the new
   18781        interfaces (so EGCS 1.0.1 and EGCS 1.0 code can be freely mixed,
   18782        and EGCS 1.0.1 and GCC 2.8.0 code can be freely mixed).
   18783        The maintainers of GCC 2.x have decided against including seamless
   18784        support for the old interface in 2.8.0, since it was never
   18785        "official", so to avoid future compatibility problems we recommend
   18786        against distributing any shared libraries built by EGCS 1.0 that
   18787        contain C++ code (upgrade to 1.0.1 and use that).
   18788      * Various bugfixes in the x86, hppa, mips, and rs6000/ppc back ends.
   18789        The x86 changes fix code generation errors exposed when building
   18790        glibc2 and the usual GNU/Linux dynamic linker (ld.so).
   18791        The hppa change fixes a compiler abort when configured for use with
   18792        RTEMS.
   18793        The MIPS changes fix problems with the definition of LONG_MAX on
   18794        newer systems, allow for command line selection of the target ABI,
   18795        and fix one code generation problem.
   18796        The rs6000/ppc change fixes some problems with passing structures
   18797        to varargs/stdarg functions.
   18798      * A few machine independent bugfixes, mostly to fix code generation
   18799        errors when building Linux kernels or glibc.
   18800      * Fix a few critical exception handling and template bugs in the C++
   18801        compiler.
   18802      * Fix Fortran namelist bug on alphas.
   18803      * Fix build problems on x86-solaris systems.
   18804 
   18805    EGCS 1.0.2 is a minor update to the EGCS 1.0.1 compiler to fix several
   18806    serious problems in EGCS 1.0.1.
   18807      * General improvements and fixes
   18808           + Memory consumption significantly reduced, especially for
   18809             templates and inline functions.
   18810           + Fix various problems with glibc2.1.
   18811           + Fix loop optimization bug exposed by rs6000/ppc port.
   18812           + Fix to avoid potential code generation problems in jump.c.
   18813           + Fix some undefined symbol problems in dwarf1 debug support.
   18814      * g++/libstdc++ improvements and fixes
   18815           + libstdc++ in the EGCS release has been updated and should be
   18816             link compatible with libstdc++-2.8.
   18817           + Various fixes in libio/libstdc++ to work better on GNU/Linux
   18818             systems.
   18819           + Fix problems with duplicate symbols on systems that do not
   18820             support weak symbols.
   18821           + Memory corruption bug and undefined symbols in bastring have
   18822             been fixed.
   18823           + Various exception handling fixes.
   18824           + Fix compiler abort for very long thunk names.
   18825      * g77 improvements and fixes
   18826           + Fix compiler crash for omitted bound in Fortran CASE
   18827             statement.
   18828           + Add missing entries to g77 lang-options.
   18829           + Fix problem with -fpedantic in the g77 compiler.
   18830           + Fix "backspace" problem with g77 on alphas.
   18831           + Fix x86 backend problem with Fortran literals and -fpic.
   18832           + Fix some of the problems with negative subscripts for g77 on
   18833             alphas.
   18834           + Fixes for Fortran builds on cygwin32/mingw32.
   18835      * platform specific improvements and fixes
   18836           + Fix long double problems on x86 (exposed by glibc).
   18837           + x86 ports define i386 again to keep imake happy.
   18838           + Fix exception handling support on NetBSD ports.
   18839           + Several changes to collect2 to fix many problems with AIX.
   18840           + Define __ELF__ for GNU/Linux on rs6000.
   18841           + Fix -mcall-linux problem on GNU/Linux on rs6000.
   18842           + Fix stdarg/vararg problem for GNU/Linux on rs6000.
   18843           + Allow autoconf to select a proper install problem on AIX 3.1.
   18844           + m68k port support includes -mcpu32 option as well as cpu32
   18845             multilibs.
   18846           + Fix stdarg bug for irix6.
   18847           + Allow EGCS to build on irix5 without the gnu assembler.
   18848           + Fix problem with static linking on sco5.
   18849           + Fix bootstrap on sco5 with native compiler.
   18850           + Fix for abort building newlib on H8 target.
   18851           + Fix fixincludes handling of math.h on SunOS.
   18852           + Minor fix for Motorola 3300 m68k systems.
   18853 
   18854    EGCS 1.0.3 is a minor update to the EGCS 1.0.2 compiler to fix a few
   18855    problems reported by Red Hat for builds of Red Hat 5.1.
   18856      * Generic bugfixes:
   18857           + Fix a typo in the libio library which resulted in incorrect
   18858             behavior of istream::get.
   18859           + Fix the Fortran negative array index problem.
   18860           + Fix a major problem with the ObjC runtime thread support
   18861             exposed by glibc2.
   18862           + Reduce memory consumption of the Haifa scheduler.
   18863      * Target specific bugfixes:
   18864           + Fix one x86 floating point code generation bug exposed by
   18865             glibc2 builds.
   18866           + Fix one x86 internal compiler error exposed by glibc2 builds.
   18867           + Fix profiling bugs on the Alpha.
   18868           + Fix ImageMagick & emacs 20.2 build problems on the Alpha.
   18869           + Fix rs6000/ppc bug when converting values from integer types
   18870             to floating point types.
   18871 
   18872    The EGCS 1.0 releases include installation instructions in both HTML
   18873    and plaintext forms (see the INSTALL directory in the toplevel
   18874    directory of the distribution). However, we also keep the most up to
   18875    date installation instructions and [2]build/test status on our web
   18876    page. We will update those pages as new information becomes available.
   18877 
   18878    And, we can't in good conscience fail to mention some [3]caveats to
   18879    using EGCS.
   18880 
   18881    Update: Big thanks to Stanford for providing a high speed link for
   18882    downloading EGCS (go.cygnus.com)!
   18883 
   18884    Download EGCS from ftp.cygnus.com (USA California) or go.cygnus.com
   18885    (USA California -- High speed link provided by Stanford).
   18886 
   18887    The EGCS 1.0 release is also available many mirror sites.
   18888    [4]Goto mirror list to find a closer site
   18889 
   18890    We'd like to thank the numerous people that have contributed new
   18891    features, test results, bugfixes, etc. Unfortunately, they're far too
   18892    numerous to mention by name.
   18893 
   18894 
   18895     For questions related to the use of GCC, please consult these web
   18896     pages and the [5]GCC manuals. If that fails, the
   18897     [6]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18898     web pages and the development of GCC are welcome on our developer
   18899     list at [7]gcc (a] gcc.gnu.org. All of [8]our lists have public archives.
   18900 
   18901    Copyright (C) [9]Free Software Foundation, Inc. Verbatim copying and
   18902    distribution of this entire article is permitted in any medium,
   18903    provided this notice is preserved.
   18904 
   18905    These pages are [10]maintained by the GCC team. Last modified
   18906    2019-11-28[11].
   18907 
   18908 References
   18909 
   18910    1. http://gcc.gnu.org/egcs-1.0/features.html
   18911    2. http://gcc.gnu.org/egcs-1.0/buildstat.html
   18912    3. http://gcc.gnu.org/egcs-1.0/caveats.html
   18913    4. http://gcc.gnu.org/mirrors.html
   18914    5. https://gcc.gnu.org/onlinedocs/
   18915    6. mailto:gcc-help (a] gcc.gnu.org
   18916    7. mailto:gcc (a] gcc.gnu.org
   18917    8. https://gcc.gnu.org/lists.html
   18918    9. https://www.fsf.org/
   18919   10. https://gcc.gnu.org/about.html
   18920   11. http://validator.w3.org/check/referer
   18921 ======================================================================
   18922 http://gcc.gnu.org/egcs-1.0/features.html
   18923                                EGCS 1.0 features
   18924 
   18925      * Core compiler is based on the gcc2 development tree from Aug 2,
   18926        1997, so we have most of the [1]features found in GCC 2.8.
   18927      * Integrated GNU Fortran compiler based on g77-0.5.22-19970929.
   18928      * Vast improvements in the C++ compiler; so many they have [2]page of
   18929        their own!
   18930      * Integrated C++ runtime libraries, including support for most major
   18931        GNU/Linux systems!
   18932      * New instruction scheduler from IBM Haifa which includes support for
   18933        function wide instruction scheduling as well as superscalar
   18934        scheduling.
   18935      * Significantly improved alias analysis code.
   18936      * Improved register allocation for two address machines.
   18937      * Significant code generation improvements for Fortran code on
   18938        Alphas.
   18939      * Various optimizations from the g77 project as well as improved loop
   18940        optimizations.
   18941      * Dwarf2 debug format support for some targets.
   18942      * egcs libstdc++ includes the SGI STL implementation without changes.
   18943      * As a result of these and other changes, egcs libstc++ is not binary
   18944        compatible with previous releases of libstdc++.
   18945      * Various new ports -- UltraSPARC, Irix6.2 & Irix6.3 support, The SCO
   18946        Openserver 5 family (5.0.{0,2,4} and Internet FastStart 1.0 and
   18947        1.1), Support for RTEMS on several embedded targets, Support for
   18948        arm-linux, Mitsubishi M32R, Hitachi H8/S, Matsushita MN102 and
   18949        MN103, NEC V850, Sparclet, Solaris & GNU/Linux on PowerPCs, etc.
   18950      * Integrated testsuites for gcc, g++, g77, libstdc++ and libio.
   18951      * RS6000/PowerPC ports generate code which can run on all
   18952        RS6000/PowerPC variants by default.
   18953      * -mcpu= and -march= switches for the x86 port to allow better
   18954        control over how the x86 port generates code.
   18955      * Includes the template repository patch (aka repo patch); note the
   18956        new template code makes repo obsolete for ELF systems using gnu-ld
   18957        such as GNU/Linux.
   18958      * Plus the usual assortment of bugfixes and improvements.
   18959 
   18960 
   18961     For questions related to the use of GCC, please consult these web
   18962     pages and the [3]GCC manuals. If that fails, the
   18963     [4]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   18964     web pages and the development of GCC are welcome on our developer
   18965     list at [5]gcc (a] gcc.gnu.org. All of [6]our lists have public archives.
   18966 
   18967    Copyright (C) [7]Free Software Foundation, Inc. Verbatim copying and
   18968    distribution of this entire article is permitted in any medium,
   18969    provided this notice is preserved.
   18970 
   18971    These pages are [8]maintained by the GCC team. Last modified
   18972    2019-11-28[9].
   18973 
   18974 References
   18975 
   18976    1. http://gcc.gnu.org/egcs-1.0/features-2.8.html
   18977    2. http://gcc.gnu.org/egcs-1.0/c++features.html
   18978    3. https://gcc.gnu.org/onlinedocs/
   18979    4. mailto:gcc-help (a] gcc.gnu.org
   18980    5. mailto:gcc (a] gcc.gnu.org
   18981    6. https://gcc.gnu.org/lists.html
   18982    7. https://www.fsf.org/
   18983    8. https://gcc.gnu.org/about.html
   18984    9. http://validator.w3.org/check/referer
   18985 ======================================================================
   18986 http://gcc.gnu.org/egcs-1.0/caveats.html
   18987                                 EGCS 1.0 Caveats
   18988 
   18989      * EGCS has an integrated libstdc++, but does not have an integrated
   18990        libg++. Furthermore old libg++ releases will not work with egc; HJ
   18991        Lu has made a libg++-2.8.1.2 available which may work with EGCS.
   18992        Note most C++ programs only need libstdc++.
   18993      * Note that using -pedantic or -Wreturn-type can cause an explosion
   18994        in the amount of memory needed for template-heavy C++ code, such as
   18995        code that uses STL. Also note that -Wall includes -Wreturn-type, so
   18996        if you use -Wall you will need to specify -Wno-return-type to turn
   18997        it off.
   18998      * Exception handling may not work with shared libraries, particularly
   18999        on alphas, hppas, and mips based platforms. Exception handling is
   19000        known to work on x86-linux platforms with shared libraries.
   19001      * Some versions of the Linux kernel have bugs which prevent them from
   19002        being compiled or from running when compiled by EGCS. See the FAQ
   19003        (as shipped with EGCS 1.0) for additional information.
   19004      * In general, EGCS is more rigorous about rejecting invalid C++ code
   19005        or deprecated C++ constructs than G++ 2.7. As a result it may be
   19006        necessary to fix C++ code before it will compile with EGCS.
   19007      * G++ is also aggressively tracking the C++ standard; as a result
   19008        code which was previously valid (and thus accepted by other
   19009        compilers and older versions of G++) may no longer be accepted.
   19010      * EGCS 1.0 may not work with Red Hat Linux 5.0 on all targets. EGCS
   19011        1.0.x and later releases should work with Red Hat Linux 5.0.
   19012 
   19013 
   19014     For questions related to the use of GCC, please consult these web
   19015     pages and the [1]GCC manuals. If that fails, the
   19016     [2]gcc-help (a] gcc.gnu.org mailing list might help. Comments on these
   19017     web pages and the development of GCC are welcome on our developer
   19018     list at [3]gcc (a] gcc.gnu.org. All of [4]our lists have public archives.
   19019 
   19020    Copyright (C) [5]Free Software Foundation, Inc. Verbatim copying and
   19021    distribution of this entire article is permitted in any medium,
   19022    provided this notice is preserved.
   19023 
   19024    These pages are [6]maintained by the GCC team. Last modified
   19025    2019-11-28[7].
   19026 
   19027 References
   19028 
   19029    1. https://gcc.gnu.org/onlinedocs/
   19030    2. mailto:gcc-help (a] gcc.gnu.org
   19031    3. mailto:gcc (a] gcc.gnu.org
   19032    4. https://gcc.gnu.org/lists.html
   19033    5. https://www.fsf.org/
   19034    6. https://gcc.gnu.org/about.html
   19035    7. http://validator.w3.org/check/referer
   19036 ======================================================================
   19037