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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-4.5/index.html
9
 
10
                           GCC 4.5 Release Series
11
 
12
   July 31, 2010
13
 
14
   The [1]GNU project and the GCC developers are pleased to announce the
15
   release of GCC 4.5.1.
16
 
17
   This release is a bug-fix release, containing fixes for regressions in
18
   GCC 4.5.0 relative to previous releases of GCC.
19
 
20
Release History
21
 
22
   GCC 4.5.1
23
          Jul 31, 2010 ([2]changes)
24
 
25
   GCC 4.5.0
26
          April 14, 2010 ([3]changes)
27
 
28
References and Acknowledgements
29
 
30
   GCC used to stand for the GNU C Compiler, but since the compiler
31
   supports several other languages aside from C, it now stands for the
32
   GNU Compiler Collection.
33
 
34
   A list of [4]successful builds is updated as new information becomes
35
   available.
36
 
37
   The GCC developers would like to thank the numerous people that have
38
   contributed new features, improvements, bug fixes, and other changes as
39
   well as test results to GCC. This [5]amazing group of volunteers is
40
   what makes GCC successful.
41
 
42
   For additional information about GCC please refer to the [6]GCC project
43
   web site or contact the [7]GCC development mailing list.
44
 
45
   To obtain GCC please use [8]our mirror sites or [9]our SVN server.
46
 
47
   Please send FSF & GNU inquiries & questions to [10]gnu@gnu.org. There
48
   are also [11]other ways to contact the FSF.
49
 
50
   These pages are [12]maintained by the GCC team.
51
 
52
 
53
    For questions related to the use of GCC, please consult these web
54
    pages and the [13]GCC manuals. If that fails, the
55
    [14]gcc-help@gcc.gnu.org mailing list might help.
56
    Please send comments on these web pages and the development of GCC to
57
    our developer mailing list at [15]gcc@gnu.org or [16]gcc@gcc.gnu.org.
58
    All of our lists have [17]public archives.
59
 
60
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
61
   Floor, Boston, MA 02110, USA.
62
 
63
   Verbatim copying and distribution of this entire article is permitted
64
   in any medium, provided this notice is preserved.
65
   Last modified 2010-07-31 [18]Valid XHTML 1.0
66
 
67
References
68
 
69
   1. http://www.gnu.org/
70
   2. http://gcc.gnu.org/gcc-4.5/changes.html
71
   3. http://gcc.gnu.org/gcc-4.5/changes.html
72
   4. http://gcc.gnu.org/gcc-4.5/buildstat.html
73
   5. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
74
   6. http://gcc.gnu.org/index.html
75
   7. mailto:gcc@gcc.gnu.org
76
   8. http://gcc.gnu.org/mirrors.html
77
   9. http://gcc.gnu.org/svn.html
78
  10. mailto:gnu@gnu.org
79
  11. http://www.gnu.org/home.html#ContactInfo
80
  12. http://gcc.gnu.org/about.html
81
  13. http://gcc.gnu.org/onlinedocs/
82
  14. mailto:gcc-help@gcc.gnu.org
83
  15. mailto:gcc@gnu.org
84
  16. mailto:gcc@gcc.gnu.org
85
  17. http://gcc.gnu.org/lists.html
86
  18. http://validator.w3.org/check/referer
87
======================================================================
88
http://gcc.gnu.org/gcc-4.5/changes.html
89
 
90
                           GCC 4.5 Release Series
91
                      Changes, New Features, and Fixes
92
 
93
Caveats
94
 
95
     * GCC now requires the [1]MPC library in order to build. See the
96
       [2]prerequisites page for version requirements.
97
     * Support for a number of older systems and recently unmaintained or
98
       untested target ports of GCC has been declared obsolete in GCC 4.5.
99
       Unless there is activity to revive them, the next release of GCC
100
       will have their sources permanently removed.
101
       The following ports for individual systems on particular
102
       architectures have been obsoleted:
103
          + IRIX releases before 6.5 (mips-sgi-irix5*,
104
            mips-sgi-irix6.[0-4])
105
          + Solaris 7 (*-*-solaris2.7)
106
          + Tru64 UNIX releases before V5.1 (alpha*-dec-osf4*,
107
            alpha-dec-osf5.0*)
108
          + Details for the IRIX, Solaris 7, and Tru64 UNIX obsoletions
109
            can be found in the [3]announcement.
110
       Support for the classic POWER architecture implemented in the
111
       original RIOS and RIOS2 processors of the old IBM RS/6000 product
112
       line has been obsoleted in the rs6000 port. This does not affect
113
       the new generation Power and PowerPC architectures.
114
     * Support has been removed for all the [4]configurations obsoleted in
115
       GCC 4.4.
116
     * Support has been removed for the protoize and unprotoize utilities,
117
       obsoleted in GCC 4.4.
118
     * Support has been removed for tuning for Itanium1 (Merced) variants.
119
       Note that code tuned for Itanium2 should also run correctly on
120
       Itanium1.
121
     * GCC now generates unwind info also for epilogues. DWARF debuginfo
122
       generated by GCC now uses more features of DWARF3 than it used to
123
       do and also some DWARF4 features. GDB older than 7.0 is not able to
124
       handle either of these, so to debug GCC 4.5 generated binaries or
125
       libraries GDB 7.0 or later is needed. You can disable use of DWARF4
126
       features with -gdwarf-3 -gstrict-dwarf options, or with -gdwarf-2
127
       -gstrict-dwarf restrict GCC to just DWARF2 standard, but epilogue
128
       unwind info is emitted unconditionally whenever unwind info is
129
       emitted.
130
     * On x86 targets, code containing floating-point calculations may run
131
       significantly slower when compiled with GCC 4.5 in strict C99
132
       conformance mode than they did with earlier GCC versions. This is
133
       due to stricter standard conformance of the compiler and can be
134
       avoided by using the option -fexcess-precision=fast; also see
135
       [5]below.
136
     * The function attribute noinline no longer prevents GCC from cloning
137
       the function. A new attribute noclone has been introduced for this
138
       purpose. Cloning a function means that it is duplicated and the new
139
       copy is specialized for certain contexts (for example when a
140
       parameter is a known constant).
141
 
142
General Optimizer Improvements
143
 
144
     * The -save-temps now takes an optional argument. The -save-temps and
145
       -save-temps=cwd switches write the temporary files in the current
146
       working directory based on the original source file. The
147
       -save-temps=obj switch will write files into the directory
148
       specified with the -o option, and the intermediate filenames are
149
       based on the output file. This will allow the user to get the
150
       compiler intermediate files when doing parallel builds without two
151
       builds of the same filename located in different directories from
152
       interfering with each other.
153
     * Debugging dumps are now created in the same directory as the object
154
       file rather than in the current working directory. This allows the
155
       user to get debugging dumps when doing parallel builds without two
156
       builds of the same filename interfering with each other.
157
     * GCC has been integrated with the [6]MPC library. This allows GCC to
158
       evaluate complex arithmetic at compile time [7]more accurately. It
159
       also allows GCC to evaluate calls to complex built-in math
160
       functions having constant arguments and replace them at compile
161
       time with their mathematically equivalent results. In doing so, GCC
162
       can generate correct results regardless of the math library
163
       implementation or floating point precision of the host platform.
164
       This also allows GCC to generate identical results regardless of
165
       whether one compiles in native or cross-compile configurations to a
166
       particular target. The following built-in functions take advantage
167
       of this new capability: cacos, cacosh, casin, casinh, catan,
168
       catanh, ccos, ccosh, cexp, clog, cpow, csin, csinh, csqrt, ctan,
169
       and ctanh. The float and long double variants of these functions
170
       (e.g. csinf and csinl) are also handled.
171
     * A new link-time optimizer has been added ([8]-flto). When this
172
       option is used, GCC generates a bytecode representation of each
173
       input file and writes it to special ELF sections in each object
174
       file. When the object files are linked together, all the function
175
       bodies are read from these ELF sections and instantiated as if they
176
       had been part of the same translation unit. This enables
177
       interprocedural optimizations to work across different files (and
178
       even different languages), potentially improving the performance of
179
       the generated code. To use the link-timer optimizer, -flto needs to
180
       be specified at compile time and during the final link. If the
181
       program does not require any symbols to be exported, it is possible
182
       to combine -flto and the experimental [9]-fwhopr with
183
       [10]-fwhole-program to allow the interprocedural optimizers to use
184
       more aggressive assumptions.
185
     * The automatic parallelization pass was enhanced to support
186
       parallelization of outer loops.
187
     * Automatic parallelization can be enabled as part of Graphite. In
188
       addition to -ftree-parallelize-loops=, specify
189
       -floop-parallelize-all to enable the Graphite-based optimization.
190
     * The infrastructure for optimizing based on [11]restrict qualified
191
       pointers has been rewritten and should result in code generation
192
       improvements. Optimizations based on restrict qualified pointers
193
       are now also available when using -fno-strict-aliasing.
194
     * There is a new optimization pass that attempts to change prototype
195
       of functions to avoid unused parameters, pass only relevant parts
196
       of structures and turn arguments passed by reference to arguments
197
       passed by value when possible. It is enabled by -O2 and above as
198
       well as -Os and can be manually invoked using the new command-line
199
       switch -fipa-sra.
200
     * GCC now optimize exception handling code. In particular cleanup
201
       regions that are proved to not have any effect are optimized out.
202
 
203
New Languages and Language specific improvements
204
 
205
  All languages
206
 
207
     * The -fshow-column option is now on by default. This means error
208
       messages now have a column associated with them.
209
 
210
  Ada
211
 
212
     * Compilation of programs heavily using discriminated record types
213
       with variant parts has been sped up and generates more compact
214
       code.
215
     * Stack checking now works reasonably well on most plaforms. In some
216
       specific cases, stack overflows may still fail to be detected, but
217
       a compile-time warning will be issued for these cases.
218
 
219
  C family
220
 
221
     * If a header named in a #include directive is not found, the
222
       compiler exits immediately. This avoids a cascade of errors arising
223
       from declarations expected to be found in that header being
224
       missing.
225
     * A new built-in function __builtin_unreachable() has been added that
226
       tells the compiler that control will never reach that point. It may
227
       be used after asm statements that terminate by transferring control
228
       elsewhere, and in other places that are known to be unreachable.
229
     * The -Wlogical-op option now warns for logical expressions such as
230
       (c == 1 && c == 2) and (c != 1 || c != 2), which are likely to be
231
       mistakes. This option is disabled by default.
232
     * An asm goto feature has been added to allow asm statements that
233
       jump to C labels.
234
     * C++0x raw strings are supported for C++ and for C with -std=gnu99.
235
     * The deprecated attribute now takes an optional string argument, for
236
       example, __attribute__((deprecated("text string"))), that will be
237
       printed together with the deprecation warning.
238
 
239
  C
240
 
241
     * The -Wenum-compare option, which warns when comparing values of
242
       different enum types, now works for C. It formerly only worked for
243
       C++. This warning is enabled by -Wall. It may be avoided by using a
244
       type cast.
245
     * The -Wcast-qual option now warns about casts which are unsafe in
246
       that they permit const-correctness to be violated without further
247
       warnings. Specifically, it warns about cases where a qualifier is
248
       added when all the lower types are not const. For example, it warns
249
       about a cast from char ** to const char **.
250
     * The -Wc++-compat option is significantly improved. It issues new
251
       warnings for:
252
          + Using C++ reserved operator names as identifiers.
253
          + Conversions to enum types without explicit casts.
254
          + Using va_arg with an enum type.
255
          + Using different enum types in the two branches of ?:.
256
          + Using ++ or -- on a variable of enum type.
257
          + Using the same name as both a struct, union or enum tag and a
258
            typedef, unless the typedef refers to the tagged type itself.
259
          + Using a struct, union, or enum which is defined within another
260
            struct or union.
261
          + A struct field defined using a typedef if there is a field in
262
            the struct, or an enclosing struct, whose name is the typedef
263
            name.
264
          + Duplicate definitions at file scope.
265
          + Uninitialized const variables.
266
          + A global variable with an anonymous struct, union, or enum
267
            type.
268
          + Using a string constant to initialize a char array whose size
269
            is the length of the string.
270
     * The new -Wjump-misses-init option warns about cases where a goto or
271
       switch skips the initialization of a variable. This sort of branch
272
       is an error in C++ but not in C. This warning is enabled by
273
       -Wc++-compat.
274
     * GCC now ensures that a C99-conforming  is present on most
275
       targets, and uses information about the types in this header to
276
       implement the Fortran bindings to those types. GCC does not ensure
277
       the presence of such a header, and does not implement the Fortran
278
       bindings, on the following targets: NetBSD, VxWorks, VMS,
279
       SymbianOS, WinCE, LynxOS, Netware, QNX, Interix, TPF.
280
     * GCC now implements C90- and C99-conforming rules for constant
281
       expressions. This may cause warnings or errors for some code using
282
       expressions that can be folded to a constant but are not constant
283
       expressions as defined by ISO C.
284
     * All known target-independent C90 and C90 Amendment 1 conformance
285
       bugs, and all known target-independent C99 conformance bugs not
286
       related to floating point or extended identifiers, have been fixed.
287
     * The C decimal floating point support now includes support for the
288
       FLOAT_CONST_DECIMAL64 pragma.
289
     * The named address space feature from ISO/IEC TR 18037 is now
290
       supported. This is currently only implemented for the SPU
291
       processor.
292
 
293
  C++
294
 
295
     * Improved [12]experimental support for the upcoming C++0x ISO C++
296
       standard, including support for raw strings, lambda expressions and
297
       explicit type conversion operators.
298
     * When printing the name of a class template specialization, G++ will
299
       now omit any template arguments which come from default template
300
       arguments. This behavior (and the pretty-printing of function
301
       template specializations as template signature and arguments) can
302
       be disabled with the -fno-pretty-templates option.
303
     * Access control is now applied to typedef names used in a template,
304
       which may cause G++ to reject some ill-formed code that was
305
       accepted by earlier releases. The -fno-access-control option can be
306
       used as a temporary workaround until the code is corrected.
307
     * Compilation time for code that uses templates should now scale
308
       linearly with the number of instantiations rather than
309
       quadratically, as template instantiations are now looked up using
310
       hash tables.
311
     * Declarations of functions that look like builtin declarations of
312
       library functions are only considered to be redeclarations if they
313
       are declared with extern "C". This may cause problems with code
314
       that omits extern "C" on hand-written declarations of C library
315
       functions such as abort or memcpy. Such code is ill-formed, but was
316
       accepted by earlier releases.
317
     * Diagnostics that used to complain about passing non-POD types to
318
       ... or jumping past the declaration of a non-POD variable now check
319
       for triviality rather than PODness, as per C++0x.
320
     * In C++0x mode local and anonymous classes are now allowed as
321
       template arguments, and in declarations of variables and functions
322
       with linkage, so long as any such declaration that is used is also
323
       defined ([13]DR 757).
324
     * Labels may now have attributes, as has been permitted for a while
325
       in C. This is only permitted when the label definition and the
326
       attribute specifier is followed by a semicolon--i.e., the label
327
       applies to an empty statement. The only useful attribute for a
328
       label is unused.
329
     * G++ now implements [14]DR 176. Previously G++ did not support using
330
       the injected-class-name of a template base class as a type name,
331
       and lookup of the name found the declaration of the template in the
332
       enclosing scope. Now lookup of the name finds the
333
       injected-class-name, which can be used either as a type or as a
334
       template, depending on whether or not the name is followed by a
335
       template argument list. As a result of this change, some code that
336
       was previously accepted may be ill-formed because
337
         1. The injected-class-name is not accessible because it's from a
338
            private base, or
339
         2. The injected-class-name cannot be used as an argument for a
340
            template template parameter.
341
       In either of these cases, the code can be fixed by adding a
342
       nested-name-specifier to explicitly name the template. The first
343
       can be worked around with -fno-access-control; the second is only
344
       rejected with -pedantic.
345
     * A new standard mangling for SIMD vector types has been added, to
346
       avoid name clashes on systems with vectors of varying length. By
347
       default the compiler still uses the old mangling, but emits aliases
348
       with the new mangling on targets that support strong aliases. Users
349
       can switch over entirely to the new mangling with -fabi-version=4
350
       or -fabi-version=0. -Wabi will now warn about code that uses the
351
       old mangling.
352
     * The command-line option -ftemplate-depth-N is now written as
353
       -ftemplate-depth=N and the old form is deprecated.
354
     * Conversions between NULL and non-pointer types are now warned by
355
       default. The new option -Wno-conversion-null disables these
356
       warnings. Previously these warnings were only available when using
357
       -Wconversion explicitly.
358
 
359
    Runtime Library (libstdc++)
360
 
361
     * [15]Improved experimental support for the upcoming ISO C++
362
       standard, C++0x, including:
363
          + Support for , , and .
364
          + Existing facilities now exploit explicit operators and the
365
            newly implemented core C++0x features.
366
     * An experimental [16]profile mode has been added. This is an
367
       implementation of many C++ standard library constructs with an
368
       additional analysis layer that gives performance improvement advice
369
       based on recognition of suboptimal usage patterns. For example,
370
#include 
371
int main()
372
{
373
  std::vector v;
374
  for (int k = 0; k < 1024; ++k)
375
    v.insert(v.begin(), k);
376
}
377
 
378
       When instrumented via the profile mode, can return suggestions
379
       about the initial size and choice of the container used as follows:
380
vector-to-list: improvement = 5: call stack = 0x804842c ...
381
    : advice = change std::vector to std::list
382
vector-size: improvement = 3: call stack = 0x804842c ...
383
    : advice = change initial container size from 0 to 1024
384
 
385
       These constructs can be substituted for the normal libstdc++
386
       constructs on a piecemeal basis, or all existing components can be
387
       transformed via the -D_GLIBCXX_PROFILE macro.
388
     * [17]Support for decimal floating-point arithmetic (aka ISO C++ TR
389
       24733) has been added. This support is in header file
390
       , uses namespace std::decimal, and includes
391
       classes decimal32, decimal64, and decimal128.
392
     * Sources have been audited for application of function attributes
393
       nothrow, const, pure, and noreturn.
394
     * Python pretty-printers have been added for many standard library
395
       components that simplify the internal representation and present a
396
       more intuitive view of components when used with
397
       appropriately-advanced versions of GDB. For more information,
398
       please consult the more [18]detailed description.
399
     * The default behavior for comparing typeinfo names has changed, so
400
       in , __GXX_MERGED_TYPEINFO_NAMES now defaults to zero.
401
     * The new -static-libstdc++ option directs g++ to link the C++
402
       library statically, even if the default would normally be to link
403
       it dynamically.
404
 
405
  Fortran
406
 
407
     * The COMMON default padding has been changed - instead of adding the
408
       padding before a variable it is now added afterwards, which
409
       increases the compatibility with other vendors and helps to obtain
410
       the correct output in some cases. Cf. also the -falign-commons
411
       option ([19]added in 4.4).
412
     * The -finit-real= option now also supports the value snan for
413
       signalling not-a-number; to be effective, one additionally needs to
414
       enable trapping (e.g. via -ffpe-trap=). Note: Compile-time
415
       optimizations can turn a signalling NaN into a quiet one.
416
     * The new option -fcheck= has been added with the options bounds,
417
       array-temps, do, pointer, and recursive. The bounds and array-temps
418
       options are equivalent to -fbounds-check and
419
       -fcheck-array-temporaries. The do option checks for invalid
420
       modification of loop iteration variables, and the recursive option
421
       tests for recursive calls to subroutines/functions which are not
422
       marked as recursive. With pointer pointer association checks in
423
       calls are performed; however, neither undefined pointers nor
424
       pointers in expressions are handled. Using -fcheck=all enables all
425
       these run-time checks.
426
     * The run-time checking -fcheck=bounds now warns about invalid string
427
       lengths of character dummy arguments. Additionally, more
428
       compile-time checks have been added.
429
     * The new option [20]-fno-protect-parens has been added; if set, the
430
       compiler may reorder REAL and COMPLEX expressions without regard to
431
       parentheses.
432
     * GNU Fortran no longer links against libgfortranbegin. As before,
433
       MAIN__ (assembler symbol name) is the actual Fortran main program,
434
       which is invoked by the main function. However, main is now
435
       generated and put in the same object file as MAIN__. For the time
436
       being, libgfortranbegin still exists for backward compatibility.
437
       For details see the new [21]Mixed-Language Programming chapter in
438
       the manual.
439
     * The I/O library was restructured for performance and cleaner code.
440
     * Array assignments and WHERE are now run in parallel when OpenMP's
441
       WORKSHARE is used.
442
     * The experimental option -fwhole-file was added. The option allows
443
       whole-file checking of procedure arguments and allows for better
444
       optimizations. It can also be used with -fwhole-program, which is
445
       now also supported in gfortran.
446
     * More Fortran 2003 and Fortran 2008 mathematical functions can now
447
       be used as initialization expressions.
448
     * Some extended attributes such as STDCALL are now supported via the
449
       [22]GCC$ compiler directive.
450
     * For Fortran 77 compatibility: If -fno-sign-zero is used, the SIGN
451
       intrinsic behaves now as if zero were always positive.
452
     * For legacy compatibiliy: On Cygwin and MinGW, the special files
453
       CONOUT$ and CONIN$ (and CONERR$ which maps to CONOUT$) are now
454
       supported.
455
     * Fortran 2003 support has been extended:
456
          + Procedure-pointer function results and procedure-pointer
457
            components (including PASS),
458
          + allocatable scalars (experimental),
459
          + DEFERRED type-bound procedures,
460
          + the ERRMSG= argument of the ALLOCATE and DEALLOCATE statements
461
            have been implemented.
462
          + The ALLOCATE statement supports type-specs and the SOURCE=
463
            argument.
464
          + OPERATOR(*) and ASSIGNMENT(=) are now allowed as GENERIC
465
            type-bound procedure (i.e. as type-bound operators).
466
          + Rounding (ROUND=, RZ, ...) for output is now supported.
467
          + The INT_FAST{8,16,32,64,128}_T kind type parameters of the
468
            intrinsic module ISO_C_BINDING are now supported, except for
469
            the targets listed above as ones where GCC does not have
470
             type information.
471
          + Extensible derived types with type-bound procedure or
472
            procedure pointer with PASS attribute now have to use CLASS in
473
            line with the Fortran 2003 standard; the workaround to use
474
            TYPE is no longer supported.
475
          + [23]Experimental, incomplete support for polymorphism,
476
            including CLASS, SELECT TYPE and dynamic dispatch of
477
            type-bound procedure calls. Some features do not work yet such
478
            as unlimited polymorphism (CLASS(*)).
479
     * Fortran 2008 support has been extended:
480
          + The OPEN statement now supports the NEWUNIT= option, which
481
            returns a unique file unit, thus preventing inadvertent use of
482
            the same unit in different parts of the program.
483
          + Support for unlimited format items has been added.
484
          + The INT{8,16,32} and REAL{32,64,128} kind type parameters of
485
            the intrinsic module ISO_FORTRAN_ENV are now supported.
486
          + Using complex arguments with TAN, SINH, COSH, TANH, ASIN,
487
            ACOS, and ATAN is now possible; the functions ASINH, ACOSH,
488
            and ATANH have been added (for real and complex arguments) and
489
            ATAN(Y,X) is now an alias for ATAN2(Y,X).
490
          + The BLOCK construct has been implemented.
491
 
492
  Java (GCJ)
493
 
494
New Targets and Target Specific Improvements
495
 
496
  AIX
497
 
498
     * Full cross-toolchain support now available with GNU Binutils
499
 
500
  ARM
501
 
502
     * GCC now supports the Cortex-M0 and Cortex-A5 processors.
503
     * GCC now supports the ARM v7E-M architecture.
504
     * GCC now supports VFPv4-based FPUs and FPUs with
505
       single-precision-only VFP.
506
     * GCC has many improvements to optimization for other ARM processors,
507
       including scheduling support for the integer pipeline on Cortex-A9.
508
     * GCC now supports the IEEE 754-2008 half-precision floating-point
509
       type, and a variant ARM-specific half-precision type. This type is
510
       specified using __fp16, with the layout determined by
511
       -mfp16-format. With appropriate -mfpu options, the Cortex-A9 and
512
       VFPv4 half-precision instructions will be used.
513
     * GCC now supports the variant of AAPCS that uses VFP registers for
514
       parameter passing and return values.
515
 
516
  AVR
517
 
518
     * The -mno-tablejump option has been removed because it has the same
519
       effect as the -fno-jump-tables option.
520
     * Added support for these new AVR devices:
521
          + ATmega8U2
522
          + ATmega16U2
523
          + ATmega32U2
524
 
525
  IA-32/x86-64
526
 
527
     * GCC now will set the default for -march= based on the configure
528
       target.
529
     * GCC now supports handling floating-point excess precision arising
530
       from use of the x87 floating-point unit in a way that conforms to
531
       ISO C99. This is enabled with -fexcess-precision=standard and with
532
       standards conformance options such as -std=c99, and may be disabled
533
       using -fexcess-precision=fast.
534
     * Support for the Intel Atom processor is now available through the
535
       -march=atom and -mtune=atom options.
536
     * A new -mcrc32 option is now available to enable crc32 intrinsics.
537
     * A new -mmovbe option is now available to enable GCC to use the
538
       movbe instruction to implement __builtin_bswap32 and
539
       __builtin_bswap64.
540
     * SSE math now can be enabled by default at configure time with the
541
       new --with-fpmath=sse option.
542
     * There is a new intrinsic header file, . It should be
543
       included before using any IA-32/x86-64 intrinsics.
544
     * Support for the XOP, FMA4, and LWP instruction sets for the AMD
545
       Orochi processors are now available with the -mxop, -mfma4, and
546
       -mlwp options.
547
     * The -mabm option enables GCC to use the popcnt and lzcnt
548
       instructions on AMD processors.
549
     * The -mpopcnt option enables GCC to use the popcnt instructions on
550
       both AMD and Intel processors.
551
 
552
  M68K/ColdFire
553
 
554
     * GCC now supports ColdFire 51xx, 5221x, 5225x, 52274, 52277, 5301x
555
       and 5441x devices.
556
     * GCC now supports thread-local storage (TLS) on M68K and ColdFire
557
       processors.
558
 
559
  MeP
560
 
561
   Support has been added for the Toshiba Media embedded Processor (MeP,
562
   or mep-elf) embedded target.
563
 
564
  MIPS
565
 
566
     * GCC now supports MIPS 1004K processors.
567
     * GCC can now be configured with options --with-arch-32,
568
       --with-arch-64, --with-tune-32 and --with-tune-64 to control the
569
       default optimization separately for 32-bit and 64-bit modes.
570
     * MIPS targets now support an alternative _mcount interface, in which
571
       register $12 points to the function's save slot for register $31.
572
       This interface is selected by the -mcount-ra-address option; see
573
       the documentation for more details.
574
     * GNU/Linux targets can now generate read-only .eh_frame sections.
575
       This optimization requires GNU binutils 2.20 or above, and is only
576
       available if GCC is configured with a suitable version of binutils.
577
     * GNU/Linux targets can now attach special relocations to indirect
578
       calls, so that the linker can turn them into direct jumps or
579
       branches. This optimization requires GNU binutils 2.20 or later,
580
       and is automatically selected if GCC is configured with an
581
       appropriate version of binutils. It can be explicitly enabled or
582
       disabled using the -mrelax-pic-calls command-line option.
583
     * GCC now generates more heavily-optimized atomic operations on
584
       Octeon processors.
585
     * MIPS targets now support the -fstack-protector option.
586
     * GCC now supports an -msynci option, which specifies that synci is
587
       enough to flush the instruction cache, without help from the
588
       operating system. GCC uses this information to optimize
589
       automatically-generated cache flush operations, such as those used
590
       for nested functions in C. There is also a --with-synci
591
       configure-time option, which makes -msynci the default.
592
     * GCC supports four new function attributes for interrupt handlers:
593
       interrupt, use_shadow_register_set, keep_interrupts_masked and
594
       use_debug_exception_return. See the documentation for more details
595
       about these attributes.
596
 
597
  picochip
598
 
599
  RS/6000 (POWER/PowerPC)
600
 
601
     * GCC now supports the Power ISA 2.06, which includes the VSX
602
       instructions that add vector 64-bit floating point support, new
603
       population count instructions, and conversions between floating
604
       point and unsigned types.
605
     * Support for the power7 processor is now available through the
606
       -mcpu=power7 and -mtune=power7.
607
     * GCC will now vectorize loops that contain simple math functions
608
       like copysign when generating code for altivec or VSX targets.
609
     * Support for the A2 processor is now available through the -mcpu=a2
610
       and -mtune=a2 options.
611
     * Support for the 476 processor is now available through the
612
       -mcpu={476,476fp} and -mtune={476,476fp} options.
613
     * Support for the e500mc64 processor is now available through the
614
       -mcpu=e500mc64 and -mtune=e500mc64 options.
615
     * GCC can now be configured with options --with-cpu-32,
616
       --with-cpu-64, --with-tune-32 and --with-tune-64 to control the
617
       default optimization separately for 32-bit and 64-bit modes.
618
 
619
  RX
620
 
621
   Support has been added for the Renesas RX Processor (rx-elf) target.
622
 
623
Operating Systems
624
 
625
  Windows (Cygwin and MinGW)
626
 
627
     * GCC now installs all the major language runtime libraries as DLLs
628
       when configured with the --enable-shared option.
629
     * GCC now makes use of the new support for aligned common variables
630
       in versions of binutils >= 2.20 to fix bugs in the support for SSE
631
       data types.
632
     * Improvements to the libffi support library increase the reliability
633
       of code generated by GCJ on all Windows platforms. Libgcj is
634
       enabled by default for the first time.
635
     * Libtool improvements simplify installation by placing the generated
636
       DLLs in the correct binaries directory.
637
     * Numerous other minor bugfixes and improvements, and substantial
638
       enhancements to the Fortran language support library.
639
 
640
Documentation improvements
641
 
642
Other significant improvements
643
 
644
  Plugins
645
 
646
     * It is now possible to extend the compiler without having to modify
647
       its source code. A new option -fplugin=file.so tells GCC to load
648
       the shared object file.so and execute it as part of the compiler.
649
       The internal documentation describes the details on how plugins can
650
       interact with the compiler.
651
 
652
  Installation changes
653
 
654
     * The move to newer autotools changed default installation
655
       directories and switches to control them: The --with-datarootdir,
656
       --with-docdir, --with-pdfdir, and --with-htmldir switches are not
657
       used any more. Instead, you can now use --datarootdir, --docdir,
658
       --htmldir, and --pdfdir. The default installation directories have
659
       changed as follows according to the GNU Coding Standards:
660
 
661
       datarootdir read-only architecture-independent data root [PREFIX/share]
662
       localedir   locale-specific message catalogs [DATAROOTDIR/locale]
663
       docdir      documentation root [DATAROOTDIR/doc/PACKAGE]
664
       htmldir     html documentation [DOCDIR]
665
       dvidir      dvi documentation [DOCDIR]
666
       pdfdir      pdf documentation [DOCDIR]
667
       psdir       ps documentation [DOCDIR]
668
       The following variables have new default values:
669
 
670
       datadir read-only architecture-independent data [DATAROOTDIR]
671
       infodir info documentation [DATAROOTDIR/info]
672
       mandir  man documentation [DATAROOTDIR/man]
673
 
674
GCC 4.5.1
675
 
676
   This is the [24]list of problem reports (PRs) from GCC's bug tracking
677
   system that are known to be fixed in the 4.5.1 release. This list might
678
   not be complete (that is, it is possible that some PRs that have been
679
   fixed are not listed here).
680
 
681
  All languages
682
 
683
     * GCC's new link-time optimizer ([25]-flto) now also works on a few
684
       non-ELF targets:
685
          + Cygwin (*-cygwin*)
686
          + MinGW (*-mingw*)
687
          + Darwin on x86-64 (x86_64-apple-darwin*)
688
       LTO is not enabled by default for these targets. To enable LTO, you
689
       should configure with the --enable-lto option.
690
 
691
   Please send FSF & GNU inquiries & questions to [26]gnu@gnu.org. There
692
   are also [27]other ways to contact the FSF.
693
 
694
   These pages are [28]maintained by the GCC team.
695
 
696
 
697
    For questions related to the use of GCC, please consult these web
698
    pages and the [29]GCC manuals. If that fails, the
699
    [30]gcc-help@gcc.gnu.org mailing list might help.
700
    Please send comments on these web pages and the development of GCC to
701
    our developer mailing list at [31]gcc@gnu.org or [32]gcc@gcc.gnu.org.
702
    All of our lists have [33]public archives.
703
 
704
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
705
   Floor, Boston, MA 02110, USA.
706
 
707
   Verbatim copying and distribution of this entire article is permitted
708
   in any medium, provided this notice is preserved.
709
   Last modified 2010-07-31 [34]Valid XHTML 1.0
710
 
711
References
712
 
713
   1. http://www.multiprecision.org/
714
   2. http://gcc.gnu.org/install/prerequisites.html
715
   3. http://gcc.gnu.org/ml/gcc/2010-01/msg00510.html
716
   4. http://gcc.gnu.org/gcc-4.4/changes.html#obsoleted
717
   5. http://gcc.gnu.org/gcc-4.5/changes.html#x86
718
   6. http://www.multiprecision.org/
719
   7. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30789
720
   8. http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801
721
   9. http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhopr-802
722
  10. http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fwhole-program-800
723
  11. http://gcc.gnu.org/onlinedocs/gcc/Restricted-Pointers.html
724
  12. http://gcc.gnu.org/gcc-4.5/cxx0x_status.html
725
  13. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#757
726
  14. http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#176
727
  15. http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.200x
728
  16. http://gcc.gnu.org/onlinedocs/libstdc++/manual/profile_mode.html
729
  17. http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.tr24733
730
  18. http://sourceware.org/gdb/wiki/STLSupport
731
  19. http://gcc.gnu.org/gcc-4.4/changes.html
732
  20. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html
733
  21. http://gcc.gnu.org/onlinedocs/gfortran/Mixed-Language-Programming.html
734
  22. http://gcc.gnu.org/onlinedocs/gfortran/GNU-Fortran-Compiler-Directives.html
735
  23. http://gcc.gnu.org/wiki/OOP
736
  24. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.5.1
737
  25. http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-flto-801
738
  26. mailto:gnu@gnu.org
739
  27. http://www.gnu.org/home.html#ContactInfo
740
  28. http://gcc.gnu.org/about.html
741
  29. http://gcc.gnu.org/onlinedocs/
742
  30. mailto:gcc-help@gcc.gnu.org
743
  31. mailto:gcc@gnu.org
744
  32. mailto:gcc@gcc.gnu.org
745
  33. http://gcc.gnu.org/lists.html
746
  34. http://validator.w3.org/check/referer
747
======================================================================
748
http://gcc.gnu.org/gcc-4.4/index.html
749
 
750
                           GCC 4.4 Release Series
751
 
752
   April 29, 2010
753
 
754
   The [1]GNU project and the GCC developers are pleased to announce the
755
   release of GCC 4.4.4.
756
 
757
   This release is a bug-fix release, containing fixes for regressions in
758
   GCC 4.4.3 relative to previous releases of GCC.
759
 
760
Release History
761
 
762
   GCC 4.4.4
763
          April 29, 2010 ([2]changes)
764
 
765
   GCC 4.4.3
766
          January 21, 2010 ([3]changes)
767
 
768
   GCC 4.4.2
769
          October 15, 2009 ([4]changes)
770
 
771
   GCC 4.4.1
772
          July 22, 2009 ([5]changes)
773
 
774
   GCC 4.4.0
775
          April 21, 2009 ([6]changes)
776
 
777
References and Acknowledgements
778
 
779
   GCC used to stand for the GNU C Compiler, but since the compiler
780
   supports several other languages aside from C, it now stands for the
781
   GNU Compiler Collection.
782
 
783
   A list of [7]successful builds is updated as new information becomes
784
   available.
785
 
786
   The GCC developers would like to thank the numerous people that have
787
   contributed new features, improvements, bug fixes, and other changes as
788
   well as test results to GCC. This [8]amazing group of volunteers is
789
   what makes GCC successful.
790
 
791
   For additional information about GCC please refer to the [9]GCC project
792
   web site or contact the [10]GCC development mailing list.
793
 
794
   To obtain GCC please use [11]our mirror sites or [12]our SVN server.
795
 
796
   Please send FSF & GNU inquiries & questions to [13]gnu@gnu.org. There
797
   are also [14]other ways to contact the FSF.
798
 
799
   These pages are [15]maintained by the GCC team.
800
 
801
 
802
    For questions related to the use of GCC, please consult these web
803
    pages and the [16]GCC manuals. If that fails, the
804
    [17]gcc-help@gcc.gnu.org mailing list might help.
805
    Please send comments on these web pages and the development of GCC to
806
    our developer mailing list at [18]gcc@gnu.org or [19]gcc@gcc.gnu.org.
807
    All of our lists have [20]public archives.
808
 
809
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
810
   Floor, Boston, MA 02110, USA.
811
 
812
   Verbatim copying and distribution of this entire article is permitted
813
   in any medium, provided this notice is preserved.
814
   Last modified 2010-07-01 [21]Valid XHTML 1.0
815
 
816
References
817
 
818
   1. http://www.gnu.org/
819
   2. http://gcc.gnu.org/gcc-4.4/changes.html
820
   3. http://gcc.gnu.org/gcc-4.4/changes.html
821
   4. http://gcc.gnu.org/gcc-4.4/changes.html
822
   5. http://gcc.gnu.org/gcc-4.4/changes.html
823
   6. http://gcc.gnu.org/gcc-4.4/changes.html
824
   7. http://gcc.gnu.org/gcc-4.4/buildstat.html
825
   8. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
826
   9. http://gcc.gnu.org/index.html
827
  10. mailto:gcc@gcc.gnu.org
828
  11. http://gcc.gnu.org/mirrors.html
829
  12. http://gcc.gnu.org/svn.html
830
  13. mailto:gnu@gnu.org
831
  14. http://www.gnu.org/home.html#ContactInfo
832
  15. http://gcc.gnu.org/about.html
833
  16. http://gcc.gnu.org/onlinedocs/
834
  17. mailto:gcc-help@gcc.gnu.org
835
  18. mailto:gcc@gnu.org
836
  19. mailto:gcc@gcc.gnu.org
837
  20. http://gcc.gnu.org/lists.html
838
  21. http://validator.w3.org/check/referer
839
======================================================================
840
http://gcc.gnu.org/gcc-4.4/changes.html
841
 
842
                           GCC 4.4 Release Series
843
                      Changes, New Features, and Fixes
844
 
845
   The latest release in the 4.4 release series is [1]GCC 4.4.4.
846
 
847
Caveats
848
 
849
     * __builtin_stdarg_start has been completely removed from GCC.
850
       Support for  had been deprecated since GCC 4.0. Use
851
       __builtin_va_start as a replacement.
852
     * Some of the errors issued by the C++ front end that could be
853
       downgraded to warnings in previous releases by using -fpermissive
854
       are now warnings by default. They can be converted into errors by
855
       using -pedantic-errors.
856
     * Use of the cpp assertion extension will now emit a warning when
857
       -Wdeprecated or -pedantic is used. This extension has been
858
       deprecated for many years, but never warned about.
859
     * Packed bit-fields of type char were not properly bit-packed on many
860
       targets prior to GCC 4.4. On these targets, the fix in GCC 4.4
861
       causes an ABI change. For example there is no longer a 4-bit
862
       padding between field a and b in this structure:
863
    struct foo
864
    {
865
      char a:4;
866
      char b:8;
867
    } __attribute__ ((packed));
868
       There is a new warning to help identify fields that are affected:
869
    foo.c:5: note: Offset of packed bit-field 'b' has changed in GCC 4.4
870
       The warning can be disabled with -Wno-packed-bitfield-compat.
871
     * On ARM EABI targets, the C++ mangling of the va_list type has been
872
       changed to conform to the current revision of the EABI. This does
873
       not affect the libstdc++ library included with GCC.
874
     * The SCOUNT and POS bits of the MIPS DSP control register are now
875
       treated as global. Previous versions of GCC treated these fields as
876
       call-clobbered instead.
877
     * The MIPS port no longer recognizes the h asm constraint. It was
878
       necessary to remove this constraint in order to avoid generating
879
       unpredictable code sequences.
880
       One of the main uses of the h constraint was to extract the high
881
       part of a multiplication on 64-bit targets. For example:
882
    asm ("dmultu\t%1,%2" : "=h" (result) : "r" (x), "r" (y));
883
       You can now achieve the same effect using 128-bit types:
884
    typedef unsigned int uint128_t __attribute__((mode(TI)));
885
    result = ((uint128_t) x * y) >> 64;
886
       The second sequence is better in many ways. For example, if x and y
887
       are constants, the compiler can perform the multiplication at
888
       compile time. If x and y are not constants, the compiler can
889
       schedule the runtime multiplication better than it can schedule an
890
       asm statement.
891
     * Support for a number of older systems and recently unmaintained or
892
       untested target ports of GCC has been declared obsolete in GCC 4.4.
893
       Unless there is activity to revive them, the next release of GCC
894
       will have their sources permanently removed.
895
       The following ports for individual systems on particular
896
       architectures have been obsoleted:
897
          + Generic a.out on IA32 and m68k (i[34567]86-*-aout*,
898
            m68k-*-aout*)
899
          + Generic COFF on ARM, H8300, IA32, m68k and SH (arm-*-coff*,
900
            armel-*-coff*, h8300-*-*, i[34567]86-*-coff*, m68k-*-coff*,
901
            sh-*-*). This does not affect other more specific targets
902
            using the COFF object format on those architectures, or the
903
            more specific H8300 and SH targets (h8300-*-rtems*,
904
            h8300-*-elf*, sh-*-elf*, sh-*-symbianelf*, sh-*-linux*,
905
            sh-*-netbsdelf*, sh-*-rtems*, sh-wrs-vxworks).
906
          + 2BSD on PDP-11 (pdp11-*-bsd)
907
          + AIX 4.1 and 4.2 on PowerPC (rs6000-ibm-aix4.[12]*,
908
            powerpc-ibm-aix4.[12]*)
909
          + Tuning support for Itanium1 (Merced) variants. Note that code
910
            tuned for Itanium2 should also run correctly on Itanium1.
911
     * The protoize and unprotoize utilities have been obsoleted and will
912
       be removed in GCC 4.5. These utilities have not been installed by
913
       default since GCC 3.0.
914
     * Support has been removed for all the [2]configurations obsoleted in
915
       GCC 4.3.
916
     * Unknown -Wno-* options are now silently ignored by GCC if no other
917
       diagnostics are issued. If other diagnostics are issued, then GCC
918
       warns about the unknown options.
919
     * More information on porting to GCC 4.4 from previous versions of
920
       GCC can be found in the [3]porting guide for this release.
921
 
922
General Optimizer Improvements
923
 
924
     * A new command-line switch -findirect-inlining has been added. When
925
       turned on it allows the inliner to also inline indirect calls that
926
       are discovered to have known targets at compile time thanks to
927
       previous inlining.
928
     * A new command-line switch -ftree-switch-conversion has been added.
929
       This new pass turns simple initializations of scalar variables in
930
       switch statements into initializations from a static array, given
931
       that all the values are known at compile time and the ratio between
932
       the new array size and the original switch branches does not exceed
933
       the parameter --param switch-conversion-max-branch-ratio (default
934
       is eight).
935
     * A new command-line switch -ftree-builtin-call-dce has been added.
936
       This optimization eliminates unnecessary calls to certain builtin
937
       functions when the return value is not used, in cases where the
938
       calls can not be eliminated entirely because the function may set
939
       errno. This optimization is on by default at -O2 and above.
940
     * A new command-line switch -fconserve-stack directs the compiler to
941
       minimize stack usage even if it makes the generated code slower.
942
       This affects inlining decisions.
943
     * When the assembler supports it, the compiler will now emit unwind
944
       information using assembler .cfi directives. This makes it possible
945
       to use such directives in inline assembler code. The new option
946
       -fno-dwarf2-cfi-asm directs the compiler to not use .cfi
947
       directives.
948
     * The [4]Graphite branch has been merged. This merge has brought in a
949
       new framework for loop optimizations based on a polyhedral
950
       intermediate representation. These optimizations apply to all the
951
       languages supported by GCC. The following new code transformations
952
       are available in GCC 4.4:
953
          + -floop-interchange performs loop interchange transformations
954
            on loops. Interchanging two nested loops switches the inner
955
            and outer loops. For example, given a loop like:
956
          DO J = 1, M
957
            DO I = 1, N
958
              A(J, I) = A(J, I) * C
959
            ENDDO
960
          ENDDO
961
 
962
            loop interchange will transform the loop as if the user had
963
            written:
964
          DO I = 1, N
965
            DO J = 1, M
966
              A(J, I) = A(J, I) * C
967
            ENDDO
968
          ENDDO
969
 
970
            which can be beneficial when N is larger than the caches,
971
            because in Fortran, the elements of an array are stored in
972
            memory contiguously by column, and the original loop iterates
973
            over rows, potentially creating at each access a cache miss.
974
          + -floop-strip-mine performs loop strip mining transformations
975
            on loops. Strip mining splits a loop into two nested loops.
976
            The outer loop has strides equal to the strip size and the
977
            inner loop has strides of the original loop within a strip.
978
            For example, given a loop like:
979
          DO I = 1, N
980
            A(I) = A(I) + C
981
          ENDDO
982
 
983
            loop strip mining will transform the loop as if the user had
984
            written:
985
          DO II = 1, N, 4
986
            DO I = II, min (II + 3, N)
987
              A(I) = A(I) + C
988
            ENDDO
989
          ENDDO
990
 
991
          + -floop-block performs loop blocking transformations on loops.
992
            Blocking strip mines each loop in the loop nest such that the
993
            memory accesses of the element loops fit inside caches. For
994
            example, given a loop like:
995
          DO I = 1, N
996
            DO J = 1, M
997
              A(J, I) = B(I) + C(J)
998
            ENDDO
999
          ENDDO
1000
 
1001
            loop blocking will transform the loop as if the user had
1002
            written:
1003
          DO II = 1, N, 64
1004
            DO JJ = 1, M, 64
1005
              DO I = II, min (II + 63, N)
1006
                DO J = JJ, min (JJ + 63, M)
1007
                  A(J, I) = B(I) + C(J)
1008
                ENDDO
1009
              ENDDO
1010
            ENDDO
1011
          ENDDO
1012
 
1013
            which can be beneficial when M is larger than the caches,
1014
            because the innermost loop will iterate over a smaller amount
1015
            of data that can be kept in the caches.
1016
     * A new register allocator has replaced the old one. It is called
1017
       integrated register allocator (IRA) because coalescing, register
1018
       live range splitting, and hard register preferencing are done
1019
       on-the-fly during coloring. It also has better integration with the
1020
       reload pass. IRA is a regional register allocator which uses modern
1021
       Chaitin-Briggs coloring instead of Chow's priority coloring used in
1022
       the old register allocator. More info about IRA internals and
1023
       options can be found in the GCC manuals.
1024
     * A new instruction scheduler and software pipeliner, based on the
1025
       selective scheduling approach, has been added. The new pass
1026
       performs instruction unification, register renaming, substitution
1027
       through register copies, and speculation during scheduling. The
1028
       software pipeliner is able to pipeline non-countable loops. The new
1029
       pass is targeted at scheduling-eager in-order platforms. In GCC 4.4
1030
       it is available for the Intel Itanium platform working by default
1031
       as the second scheduling pass (after register allocation) at the
1032
       -O3 optimization level.
1033
     * When using -fprofile-generate with a multi-threaded program, the
1034
       profile counts may be slightly wrong due to race conditions. The
1035
       new -fprofile-correction option directs the compiler to apply
1036
       heuristics to smooth out the inconsistencies. By default the
1037
       compiler will give an error message when it finds an inconsistent
1038
       profile.
1039
     * The new -fprofile-dir=PATH option permits setting the directory
1040
       where profile data files are stored when using -fprofile-generate
1041
       and friends, and the directory used when reading profile data files
1042
       using -fprofile-use and friends.
1043
 
1044
New warning options
1045
 
1046
     * The new -Wframe-larger-than=NUMBER option directs GCC to emit a
1047
       warning if any stack frame is larger than NUMBER bytes. This may be
1048
       used to help ensure that code fits within a limited amount of stack
1049
       space.
1050
     * The command-line option -Wlarger-than-N is now written as
1051
       -Wlarger-than=N and the old form is deprecated.
1052
     * The new -Wno-mudflap option disables warnings about constructs
1053
       which can not be instrumented when using -fmudflap.
1054
 
1055
New Languages and Language specific improvements
1056
 
1057
     * Version 3.0 of the [5]OpenMP specification is now supported for the
1058
       C, C++, and Fortran compilers.
1059
     * New character data types, per [6]TR 19769: New character types in
1060
       C, are now supported for the C compiler in -std=gnu99 mode, as
1061
       __CHAR16_TYPE__ and __CHAR32_TYPE__, and for the C++ compiler in
1062
       -std=c++0x and -std=gnu++0x modes, as char16_t and char32_t too.
1063
 
1064
  C family
1065
 
1066
     * A new optimize attribute was added to allow programmers to change
1067
       the optimization level and particular optimization options for an
1068
       individual function. You can also change the optimization options
1069
       via the GCC optimize pragma for functions defined after the pragma.
1070
       The GCC push_options pragma and the GCC pop_options pragma allow
1071
       you temporarily save and restore the options used. The GCC
1072
       reset_options pragma restores the options to what was specified on
1073
       the command line.
1074
     * Uninitialized warnings do not require enabling optimization
1075
       anymore, that is, -Wuninitialized can be used together with -O0.
1076
       Nonetheless, the warnings given by -Wuninitialized will probably be
1077
       more accurate if optimization is enabled.
1078
     * -Wparentheses now warns about expressions such as (!x | y) and (!x
1079
       & y). Using explicit parentheses, such as in ((!x) | y), silences
1080
       this warning.
1081
     * -Wsequence-point now warns within if, while,do while and for
1082
       conditions, and within for begin/end expressions.
1083
     * A new option -dU is available to dump definitions of preprocessor
1084
       macros that are tested or expanded.
1085
 
1086
  C++
1087
 
1088
     * [7]Improved experimental support for the upcoming ISO C++ standard,
1089
       C++0x. Including support for auto, inline namespaces, generalized
1090
       initializer lists, defaulted and deleted functions, new character
1091
       types, and scoped enums.
1092
     * Those errors that may be downgraded to warnings to build legacy
1093
       code now mention -fpermissive when -fdiagnostics-show-option is
1094
       enabled.
1095
     * -Wconversion now warns if the result of a static_cast to enumeral
1096
       type is unspecified because the value is outside the range of the
1097
       enumeral type.
1098
     * -Wuninitialized now warns if a non-static reference or non-static
1099
       const member appears in a class without constructors.
1100
     * G++ now properly implements value-initialization, so objects with
1101
       an initializer of () and an implicitly defined default constructor
1102
       will be zero-initialized before the default constructor is called.
1103
 
1104
    Runtime Library (libstdc++)
1105
 
1106
     * [8]Improved experimental support for the upcoming ISO C++ standard,
1107
       C++0x, including:
1108
          + Support for , , ,
1109
            , , , ,
1110
            , and .
1111
          + unique_ptr,  additions, exception propagation, and
1112
            support for the new character types in  and .
1113
          + Existing facilities now exploit initializer lists, defaulted
1114
            and deleted functions, and the newly implemented core C++0x
1115
            features.
1116
          + Some standard containers are more efficient together with
1117
            stateful allocators, i.e., no allocator is constructed on the
1118
            fly at element construction time.
1119
     * Experimental support for non-standard pointer types in containers.
1120
     * The long standing libstdc++/30928 has been fixed for targets
1121
       running glibc 2.10 or later.
1122
     * As usual, many small and larger bug fixes, in particular quite a
1123
       few corner cases in .
1124
 
1125
  Fortran
1126
 
1127
     * GNU Fortran now employs libcpp directly instead of using cc1 as an
1128
       external preprocessor. The [9]-cpp option was added to allow manual
1129
       invocation of the preprocessor without relying on filename
1130
       extensions.
1131
     * The [10]-Warray-temporaries option warns about array temporaries
1132
       generated by the compiler, as an aid to optimization.
1133
     * The [11]-fcheck-array-temporaries option has been added, printing a
1134
       notification at run time, when an array temporary had to be created
1135
       for an function argument. Contrary to -Warray-temporaries the
1136
       warning is only printed if the array is noncontiguous.
1137
     * Improved generation of DWARF debugging symbols
1138
     * If using an intrinsic not part of the selected standard (via -std=
1139
       and -fall-intrinsics) gfortran will now treat it as if this
1140
       procedure were declared EXTERNAL and try to link to a user-supplied
1141
       procedure. -Wintrinsics-std will warn whenever this happens. The
1142
       now-useless option -Wnonstd-intrinsic was removed.
1143
     * The flag -falign-commons has been added to control the alignment of
1144
       variables in COMMON blocks, which is enabled by default in line
1145
       with previous GCC version. Using -fno-align-commons one can force
1146
       commons to be contiguous in memory as required by the Fortran
1147
       standard, however, this slows down the memory access. The option
1148
       -Walign-commons, which is enabled by default, warns when padding
1149
       bytes were added for alignment. The proper solution is to sort the
1150
       common objects by decreasing storage size, which avoids the
1151
       alignment problems.
1152
     * Fortran 2003 support has been extended:
1153
          + Wide characters (ISO 10646, UCS-4, kind=4) and UTF-8 I/O is
1154
            now supported (except internal reads from/writes to wide
1155
            strings). [12]-fbackslash now supports also \unnnn and
1156
            \Unnnnnnnn to enter Unicode characters.
1157
          + Asynchronous I/O (implemented as synchronous I/O) and the
1158
            decimal=, size=, sign=, pad=, blank=, and delim= specifiers
1159
            are now supported in I/O statements.
1160
          + Support for Fortran 2003 structure constructors and for array
1161
            constructor with typespec has been added.
1162
          + Procedure Pointers (but not yet as component in derived types
1163
            and as function results) are now supported.
1164
          + Abstract types, type extension, and type-bound procedures
1165
            (both PROCEDURE and GENERIC but not as operators). Note: As
1166
            CLASS/polymorphyic types are not implemented, type-bound
1167
            procedures with PASS accept as non-standard extension TYPE
1168
            arguments.
1169
     * Fortran 2008 support has been added:
1170
          + The -std=f2008 option and support for the file extensions
1171
            .f2008 and .F2008 has been added.
1172
          + The g0 format descriptor is now supported.
1173
          + The Fortran 2008 mathematical intrinsics ASINH, ACOSH, ATANH,
1174
            ERF, ERFC, GAMMA, LOG_GAMMA, BESSEL_*, HYPOT, and ERFC_SCALED
1175
            are now available (some of them existed as GNU extension
1176
            before). Note: The hyperbolic functions are not yet supporting
1177
            complex arguments and the three- argument version of BESSEL_*N
1178
            is not available.
1179
          + The bit intrinsics LEADZ and TRAILZ have been added.
1180
 
1181
  Java (GCJ)
1182
 
1183
  Ada
1184
 
1185
     * The Ada runtime now supports multilibs on many platforms including
1186
       x86_64, SPARC and PowerPC. Their build is enabled by default.
1187
 
1188
New Targets and Target Specific Improvements
1189
 
1190
  ARM
1191
 
1192
     * GCC now supports optimizing for the Cortex-A9, Cortex-R4 and
1193
       Cortex-R4F processors and has many other improvements to
1194
       optimization for ARM processors.
1195
     * GCC now supports the VFPv3 variant with 16 double-precision
1196
       registers with -mfpu=vfpv3-d16. The option -mfpu=vfp3 has been
1197
       renamed to -mfpu=vfpv3.
1198
     * GCC now supports the -mfix-cortex-m3-ldrd option to work around an
1199
       erratum on Cortex-M3 processors.
1200
     * GCC now supports the __sync_* atomic operations for ARM EABI
1201
       GNU/Linux.
1202
     * The section anchors optimization is now enabled by default when
1203
       optimizing for ARM.
1204
     * GCC now uses a new EABI-compatible profiling interface for EABI
1205
       targets. This requires a function __gnu_mcount_nc, which is
1206
       provided by GNU libc versions 2.8 and later.
1207
 
1208
  AVR
1209
 
1210
     * The -mno-tablejump option has been deprecated because it has the
1211
       same effect as the -fno-jump-tables option.
1212
     * Added support for these new AVR devices:
1213
          + ATA6289
1214
          + ATtiny13A
1215
          + ATtiny87
1216
          + ATtiny167
1217
          + ATtiny327
1218
          + ATmega8C1
1219
          + ATmega16C1
1220
          + ATmega32C1
1221
          + ATmega8M1
1222
          + ATmega16M1
1223
          + ATmega32M1
1224
          + ATmega32U4
1225
          + ATmega16HVB
1226
          + ATmega4HVD
1227
          + ATmega8HVD
1228
          + ATmega64C1
1229
          + ATmega64M1
1230
          + ATmega16U4
1231
          + ATmega32U6
1232
          + ATmega128RFA1
1233
          + AT90PWM81
1234
          + AT90SCR100
1235
          + M3000F
1236
          + M3000S
1237
          + M3001B
1238
 
1239
  IA-32/x86-64
1240
 
1241
     * Support for Intel AES built-in functions and code generation is
1242
       available via -maes.
1243
     * Support for Intel PCLMUL built-in function and code generation is
1244
       available via -mpclmul.
1245
     * Support for Intel AVX built-in functions and code generation is
1246
       available via -mavx.
1247
     * Automatically align the stack for local variables with alignment
1248
       requirement.
1249
     * GCC can now utilize the SVML library for vectorizing calls to a set
1250
       of C99 functions if -mveclibabi=svml is specified and you link to
1251
       an SVML ABI compatible library.
1252
     * On x86-64, the ABI has been changed in the following cases to
1253
       conform to the x86-64 ABI:
1254
          + Passing/returning structures with flexible array member:
1255
  struct foo
1256
    {
1257
      int i;
1258
      int flex[];
1259
    };
1260
          + Passing/returning structures with complex float member:
1261
  struct foo
1262
    {
1263
      int i;
1264
      __complex__ float f;
1265
    };
1266
          + Passing/returning unions with long double member:
1267
  union foo
1268
    {
1269
      int x;
1270
      long double ld;
1271
    };
1272
       Code built with previous versions of GCC that uses any of these is
1273
       not compatible with code built with GCC 4.4.0 or later.
1274
     * A new target attribute was added to allow programmers to change the
1275
       target options like -msse2 or -march=k8 for an individual function.
1276
       You can also change the target options via the GCC target pragma
1277
       for functions defined after the pragma.
1278
     * GCC can now be configured with options --with-arch-32,
1279
       --with-arch-64, --with-cpu-32, --with-cpu-64, --with-tune-32 and
1280
       --with-tune-64 to control the default optimization separately for
1281
       32-bit and 64-bit modes.
1282
 
1283
  IA-32/IA64
1284
 
1285
     * Support for __float128 (TFmode) IEEE quad type and corresponding
1286
       TCmode IEEE complex quad type is available via the soft-fp library
1287
       on IA-32/IA64 targets. This includes basic arithmetic operations
1288
       (addition, subtraction, negation, multiplication and division) on
1289
       __float128 real and TCmode complex values, the full set of IEEE
1290
       comparisons between __float128 values, conversions to and from
1291
       float, double and long double floating point types, as well as
1292
       conversions to and from signed or unsigned integer, signed or
1293
       unsigned long integer and signed or unsigned quad (TImode, IA64
1294
       only) integer types. Additionally, all operations generate the full
1295
       set of IEEE exceptions and support the full set of IEEE rounding
1296
       modes.
1297
 
1298
  M68K/ColdFire
1299
 
1300
     * GCC now supports instruction scheduling for ColdFire V1, V3 and V4
1301
       processors. (Scheduling support for ColdFire V2 processors was
1302
       added in GCC 4.3.)
1303
     * GCC now supports the -mxgot option to support programs requiring
1304
       many GOT entries on ColdFire.
1305
     * The m68k-*-linux-gnu target now builds multilibs by default.
1306
 
1307
  MIPS
1308
 
1309
     * MIPS Technologies have extended the original MIPS SVR4 ABI to
1310
       include support for procedure linkage tables (PLTs) and copy
1311
       relocations. These extensions allow GNU/Linux executables to use a
1312
       significantly more efficient code model than the one defined by the
1313
       original ABI.
1314
       GCC support for this code model is available via a new command-line
1315
       option, -mplt. There is also a new configure-time option,
1316
       --with-mips-plt, to make -mplt the default.
1317
       The new code model requires support from the assembler, the linker,
1318
       and the runtime C library. This support is available in binutils
1319
       2.19 and GLIBC 2.9.
1320
     * GCC can now generate MIPS16 code for 32-bit GNU/Linux executables
1321
       and 32-bit GNU/Linux shared libraries. This feature requires GNU
1322
       binutils 2.19 or above.
1323
     * Support for RMI's XLR processor is now available through the
1324
       -march=xlr and -mtune=xlr options.
1325
     * 64-bit targets can now perform 128-bit multiplications inline,
1326
       instead of relying on a libgcc function.
1327
     * Native GNU/Linux toolchains now support -march=native and
1328
       -mtune=native, which select the host processor.
1329
     * GCC now supports the R10K, R12K, R14K and R16K processors. The
1330
       canonical -march= and -mtune= names for these processors are
1331
       r10000, r12000, r14000 and r16000 respectively.
1332
     * GCC can now work around the side effects of speculative execution
1333
       on R10K processors. Please see the documentation of the
1334
       -mr10k-cache-barrier option for details.
1335
     * Support for the MIPS64 Release 2 instruction set has been added.
1336
       The option -march=mips64r2 enables generation of these
1337
       instructions.
1338
     * GCC now supports Cavium Networks' Octeon processor. This support is
1339
       available through the -march=octeon and -mtune=octeon options.
1340
     * GCC now supports STMicroelectronics' Loongson 2E/2F processors. The
1341
       canonical -march= and -mtune= names for these processors are
1342
       loongson2e and loongson2f.
1343
 
1344
  picochip
1345
 
1346
   Picochip is a 16-bit processor. A typical picoChip contains over 250
1347
   small cores, each with small amounts of memory. There are three
1348
   processor variants (STAN, MEM and CTRL) with different instruction sets
1349
   and memory configurations and they can be chosen using the -mae option.
1350
 
1351
   This port is intended to be a "C" only port.
1352
 
1353
  Power Architecture and PowerPC
1354
 
1355
     * GCC now supports the e300c2, e300c3 and e500mc processors.
1356
     * GCC now supports Xilinx processors with a single-precision FPU.
1357
     * Decimal floating point is now supported for e500 processors.
1358
 
1359
  S/390, zSeries and System z9/z10
1360
 
1361
     * Support for the IBM System z10 EC/BC processor has been added. When
1362
       using the -march=z10 option, the compiler will generate code making
1363
       use of instructions provided by the General-Instruction-Extension
1364
       Facility and the Execute-Extension Facility.
1365
 
1366
  VxWorks
1367
 
1368
     * GCC now supports the thread-local storage mechanism used on
1369
       VxWorks.
1370
 
1371
  Xtensa
1372
 
1373
     * GCC now supports thread-local storage (TLS) for Xtensa processor
1374
       configurations that include the Thread Pointer option. TLS also
1375
       requires support from the assembler and linker; this support is
1376
       provided in the GNU binutils beginning with version 2.19.
1377
 
1378
Documentation improvements
1379
 
1380
Other significant improvements
1381
 
1382
GCC 4.4.1
1383
 
1384
   This is the [13]list of problem reports (PRs) from GCC's bug tracking
1385
   system that are known to be fixed in the 4.4.1 release. This list might
1386
   not be complete (that is, it is possible that some PRs that have been
1387
   fixed are not listed here).
1388
 
1389
GCC 4.4.2
1390
 
1391
   This is the [14]list of problem reports (PRs) from GCC's bug tracking
1392
   system that are known to be fixed in the 4.4.2 release. This list might
1393
   not be complete (that is, it is possible that some PRs that have been
1394
   fixed are not listed here).
1395
 
1396
GCC 4.4.3
1397
 
1398
   This is the [15]list of problem reports (PRs) from GCC's bug tracking
1399
   system that are known to be fixed in the 4.4.3 release. This list might
1400
   not be complete (that is, it is possible that some PRs that have been
1401
   fixed are not listed here).
1402
 
1403
GCC 4.4.4
1404
 
1405
   This is the [16]list of problem reports (PRs) from GCC's bug tracking
1406
   system that are known to be fixed in the 4.4.4 release. This list might
1407
   not be complete (that is, it is possible that some PRs that have been
1408
   fixed are not listed here).
1409
 
1410
   Please send FSF & GNU inquiries & questions to [17]gnu@gnu.org. There
1411
   are also [18]other ways to contact the FSF.
1412
 
1413
   These pages are [19]maintained by the GCC team.
1414
 
1415
 
1416
    For questions related to the use of GCC, please consult these web
1417
    pages and the [20]GCC manuals. If that fails, the
1418
    [21]gcc-help@gcc.gnu.org mailing list might help.
1419
    Please send comments on these web pages and the development of GCC to
1420
    our developer mailing list at [22]gcc@gnu.org or [23]gcc@gcc.gnu.org.
1421
    All of our lists have [24]public archives.
1422
 
1423
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
1424
   Floor, Boston, MA 02110, USA.
1425
 
1426
   Verbatim copying and distribution of this entire article is permitted
1427
   in any medium, provided this notice is preserved.
1428
   Last modified 2010-07-10 [25]Valid XHTML 1.0
1429
 
1430
References
1431
 
1432
   1. http://gcc.gnu.org/gcc-4.4/changes.html#4.4.4
1433
   2. http://gcc.gnu.org/gcc-4.3/changes.html#obsoleted
1434
   3. http://gcc.gnu.org/gcc-4.4/porting_to.html
1435
   4. http://gcc.gnu.org/wiki/Graphite
1436
   5. http://openmp.org/wp/openmp-specifications/
1437
   6. http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1040.pdf
1438
   7. http://gcc.gnu.org/gcc-4.4/cxx0x_status.html
1439
   8. http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#id476343
1440
   9. http://gcc.gnu.org/onlinedocs/gfortran/Preprocessing-Options.html
1441
  10. http://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWarray-temporaries_007d-125
1442
  11. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfcheck-array-temporaries_007d-221
1443
  12. http://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bbackslash_007d-34
1444
  13. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.1
1445
  14. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.2
1446
  15. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.3
1447
  16. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4
1448
  17. mailto:gnu@gnu.org
1449
  18. http://www.gnu.org/home.html#ContactInfo
1450
  19. http://gcc.gnu.org/about.html
1451
  20. http://gcc.gnu.org/onlinedocs/
1452
  21. mailto:gcc-help@gcc.gnu.org
1453
  22. mailto:gcc@gnu.org
1454
  23. mailto:gcc@gcc.gnu.org
1455
  24. http://gcc.gnu.org/lists.html
1456
  25. http://validator.w3.org/check/referer
1457
======================================================================
1458
http://gcc.gnu.org/gcc-4.3/index.html
1459
 
1460
                           GCC 4.3 Release Series
1461
 
1462
   May 22, 2010
1463
 
1464
   The [1]GNU project and the GCC developers are pleased to announce the
1465
   release of GCC 4.3.5.
1466
 
1467
   This release is a bug-fix release, containing fixes for regressions in
1468
   GCC 4.3.4 relative to previous releases of GCC.
1469
 
1470
Release History
1471
 
1472
   GCC 4.3.5
1473
          May 22, 2010 ([2]changes)
1474
 
1475
   GCC 4.3.4
1476
          August 4, 2009 ([3]changes)
1477
 
1478
   GCC 4.3.3
1479
          January 24, 2009 ([4]changes)
1480
 
1481
   GCC 4.3.2
1482
          August 27, 2008 ([5]changes)
1483
 
1484
   GCC 4.3.1
1485
          June 6, 2008 ([6]changes)
1486
 
1487
   GCC 4.3.0
1488
          March 5, 2008 ([7]changes)
1489
 
1490
References and Acknowledgements
1491
 
1492
   GCC used to stand for the GNU C Compiler, but since the compiler
1493
   supports several other languages aside from C, it now stands for the
1494
   GNU Compiler Collection.
1495
 
1496
   A list of [8]successful builds is updated as new information becomes
1497
   available.
1498
 
1499
   The GCC developers would like to thank the numerous people that have
1500
   contributed new features, improvements, bug fixes, and other changes as
1501
   well as test results to GCC. This [9]amazing group of volunteers is
1502
   what makes GCC successful.
1503
 
1504
   For additional information about GCC please refer to the [10]GCC
1505
   project web site or contact the [11]GCC development mailing list.
1506
 
1507
   To obtain GCC please use [12]our mirror sites or [13]our SVN server.
1508
 
1509
   Please send FSF & GNU inquiries & questions to [14]gnu@gnu.org. There
1510
   are also [15]other ways to contact the FSF.
1511
 
1512
   These pages are [16]maintained by the GCC team.
1513
 
1514
 
1515
    For questions related to the use of GCC, please consult these web
1516
    pages and the [17]GCC manuals. If that fails, the
1517
    [18]gcc-help@gcc.gnu.org mailing list might help.
1518
    Please send comments on these web pages and the development of GCC to
1519
    our developer mailing list at [19]gcc@gnu.org or [20]gcc@gcc.gnu.org.
1520
    All of our lists have [21]public archives.
1521
 
1522
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
1523
   Floor, Boston, MA 02110, USA.
1524
 
1525
   Verbatim copying and distribution of this entire article is permitted
1526
   in any medium, provided this notice is preserved.
1527
   Last modified 2010-07-01 [22]Valid XHTML 1.0
1528
 
1529
References
1530
 
1531
   1. http://www.gnu.org/
1532
   2. http://gcc.gnu.org/gcc-4.3/changes.html
1533
   3. http://gcc.gnu.org/gcc-4.3/changes.html
1534
   4. http://gcc.gnu.org/gcc-4.3/changes.html
1535
   5. http://gcc.gnu.org/gcc-4.3/changes.html
1536
   6. http://gcc.gnu.org/gcc-4.3/changes.html
1537
   7. http://gcc.gnu.org/gcc-4.3/changes.html
1538
   8. http://gcc.gnu.org/gcc-4.3/buildstat.html
1539
   9. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
1540
  10. http://gcc.gnu.org/index.html
1541
  11. mailto:gcc@gcc.gnu.org
1542
  12. http://gcc.gnu.org/mirrors.html
1543
  13. http://gcc.gnu.org/svn.html
1544
  14. mailto:gnu@gnu.org
1545
  15. http://www.gnu.org/home.html#ContactInfo
1546
  16. http://gcc.gnu.org/about.html
1547
  17. http://gcc.gnu.org/onlinedocs/
1548
  18. mailto:gcc-help@gcc.gnu.org
1549
  19. mailto:gcc@gnu.org
1550
  20. mailto:gcc@gcc.gnu.org
1551
  21. http://gcc.gnu.org/lists.html
1552
  22. http://validator.w3.org/check/referer
1553
======================================================================
1554
http://gcc.gnu.org/gcc-4.3/changes.html
1555
 
1556
                           GCC 4.3 Release Series
1557
                      Changes, New Features, and Fixes
1558
 
1559
   The latest release in the 4.3 release series is [1]GCC 4.3.5.
1560
 
1561
Caveats
1562
 
1563
     * GCC requires the [2]GMP and [3]MPFR libraries for building all the
1564
       various front-end languages it supports. See the [4]prerequisites
1565
       page for version requirements.
1566
     * ColdFire targets now treat long double as having the same format as
1567
       double. In earlier versions of GCC, they used the 68881 long double
1568
       format instead.
1569
     * The m68k-uclinux target now uses the same calling conventions as
1570
       m68k-linux-gnu. You can select the original calling conventions by
1571
       configuring for m68k-uclinuxoldabi instead. Note that
1572
       m68k-uclinuxoldabi also retains the original 80-bit long double on
1573
       ColdFire targets.
1574
     * The -fforce-mem option has been removed because it has had no
1575
       effect in the last few GCC releases.
1576
     * The i386 -msvr3-shlib option has been removed since it is no longer
1577
       used.
1578
     * Fastcall for i386 has been changed not to pass aggregate arguments
1579
       in registers, following Microsoft compilers.
1580
     * Support for the AOF assembler has been removed from the ARM back
1581
       end; this affects only the targets arm-semi-aof and armel-semi-aof,
1582
       which are no longer recognized. We removed these targets without a
1583
       deprecation period because we discovered that they have been
1584
       unusable since GCC 4.0.0.
1585
     * Support for the TMS320C3x/C4x processor (targets c4x-* and tic4x-*)
1586
       has been removed. This support had been deprecated since GCC 4.0.0.
1587
     * Support for a number of older systems and recently unmaintained or
1588
       untested target ports of GCC has been declared obsolete in GCC 4.3.
1589
       Unless there is activity to revive them, the next release of GCC
1590
       will have their sources permanently removed.
1591
       All GCC ports for the following processor architectures have been
1592
       declared obsolete:
1593
          + Morpho MT (mt-*)
1594
       The following aliases for processor architectures have been
1595
       declared obsolete. Users should use the indicated generic target
1596
       names instead, with compile-time options such as -mcpu or
1597
       configure-time options such as --with-cpu to control the
1598
       configuration more precisely.
1599
          + strongarm*-*-*, ep9312*-*-*, xscale*-*-* (use arm*-*-*
1600
            instead).
1601
          + parisc*-*-* (use hppa*-*-* instead).
1602
          + m680[012]0-*-* (use m68k-*-* instead).
1603
       All GCC ports for the following operating systems have been
1604
       declared obsolete:
1605
          + BeOS (*-*-beos*)
1606
          + kaOS (*-*-kaos*)
1607
          + GNU/Linux using the a.out object format (*-*-linux*aout*)
1608
          + GNU/Linux using version 1 of the GNU C Library
1609
            (*-*-linux*libc1*)
1610
          + Solaris versions before Solaris 7 (*-*-solaris2.[0-6],
1611
            *-*-solaris2.[0-6].*)
1612
          + Miscellaneous System V (*-*-sysv*)
1613
          + WindISS (*-*-windiss*)
1614
       Also, those for some individual systems on particular architectures
1615
       have been obsoleted:
1616
          + UNICOS/mk on DEC Alpha (alpha*-*-unicosmk*)
1617
          + CRIS with a.out object format (cris-*-aout)
1618
          + BSD 4.3 on PA-RISC (hppa1.1-*-bsd*)
1619
          + OSF/1 on PA-RISC (hppa1.1-*-osf*)
1620
          + PRO on PA-RISC (hppa1.1-*-pro*)
1621
          + Sequent PTX on IA32 (i[34567]86-sequent-ptx4*,
1622
            i[34567]86-sequent-sysv4*)
1623
          + SCO Open Server 5 on IA32 (i[34567]86-*-sco3.2v5*)
1624
          + UWIN on IA32 (i[34567]86-*-uwin*) (support for UWIN as a host
1625
            was previously [5]removed in 2001, leaving only the support
1626
            for UWIN as a target now being deprecated)
1627
          + ChorusOS on PowerPC (powerpc-*-chorusos*)
1628
          + All VAX configurations apart from NetBSD and OpenBSD
1629
            (vax-*-bsd*, vax-*-sysv*, vax-*-ultrix*)
1630
     * The [6]-Wconversion option has been modified. Its purpose now is to
1631
       warn for implicit conversions that may alter a value. This new
1632
       behavior is available for both C and C++. Warnings about
1633
       conversions between signed and unsigned integers can be disabled by
1634
       using -Wno-sign-conversion. In C++, they are disabled by default
1635
       unless -Wsign-conversion is explicitly requested. The old behavior
1636
       of -Wconversion, that is, warn for prototypes causing a type
1637
       conversion that is different from what would happen to the same
1638
       argument in the absence of a prototype, has been moved to a new
1639
       option -Wtraditional-conversion, which is only available for C.
1640
     * The -m386, -m486, -mpentium and -mpentiumpro tuning options have
1641
       been removed because they were deprecated for more than 3 GCC major
1642
       releases. Use -mtune=i386, -mtune=i486, -mtune=pentium or
1643
       -mtune=pentiumpro as a replacement.
1644
     * The -funsafe-math-optimizations option now automatically turns on
1645
       -fno-trapping-math in addition to -fno-signed-zeros, as it enables
1646
       reassociation and thus may introduce or remove traps.
1647
     * The -ftree-vectorize option is now on by default under -O3. In
1648
       order to generate code for a SIMD extension, it has to be enabled
1649
       as well: use -maltivec for PowerPC platforms and -msse/-msse2 for
1650
       i?86 and x86_64.
1651
     * More information on porting to GCC 4.3 from previous versions of
1652
       GCC can be found in the [7]porting guide for this release.
1653
 
1654
General Optimizer Improvements
1655
 
1656
     * The GCC middle-end has been integrated with the [8]MPFR library.
1657
       This allows GCC to evaluate and replace at compile-time calls to
1658
       built-in math functions having constant arguments with their
1659
       mathematically equivalent results. In making use of [9]MPFR, GCC
1660
       can generate correct results regardless of the math library
1661
       implementation or floating point precision of the host platform.
1662
       This also allows GCC to generate identical results regardless of
1663
       whether one compiles in native or cross-compile configurations to a
1664
       particular target. The following built-in functions take advantage
1665
       of this new capability: acos, acosh, asin, asinh, atan2, atan,
1666
       atanh, cbrt, cos, cosh, drem, erf, erfc, exp10, exp2, exp, expm1,
1667
       fdim, fma, fmax, fmin, gamma_r, hypot, j0, j1, jn, lgamma_r, log10,
1668
       log1p, log2, log, pow10, pow, remainder, remquo, sin, sincos, sinh,
1669
       tan, tanh, tgamma, y0, y1 and yn. The float and long double
1670
       variants of these functions (e.g. sinf and sinl) are also handled.
1671
       The sqrt and cabs functions with constant arguments were already
1672
       optimized in prior GCC releases. Now they also use [10]MPFR.
1673
     * A new forward propagation pass on RTL was added. The new pass
1674
       replaces several slower transformations, resulting in compile-time
1675
       improvements as well as better code generation in some cases.
1676
     * A new command-line switch -frecord-gcc-switches has been added to
1677
       GCC, although it is only enabled for some targets. The switch
1678
       causes the command line that was used to invoke the compiler to be
1679
       recorded into the object file that is being created. The exact
1680
       format of this recording is target and binary file format
1681
       dependent, but it usually takes the form of a note section
1682
       containing ASCII text. The switch is related to the -fverbose-asm
1683
       switch, but that one only records the information in the assembler
1684
       output file as comments, so the information never reaches the
1685
       object file.
1686
     * The inliner heuristic is now aware of stack frame consumption. New
1687
       command-line parameters --param large-stack-frame and --param
1688
       large-stack-frame-growth can be used to limit stack frame size
1689
       growth caused by inlining.
1690
     * During feedback directed optimizations, the expected block size the
1691
       memcpy, memset and bzero functions operate on is discovered and for
1692
       cases of commonly used small sizes, specialized inline code is
1693
       generated.
1694
     * __builtin_expect no longer requires its argument to be a compile
1695
       time constant.
1696
     * Interprocedural optimization was reorganized to work on functions
1697
       in SSA form. This enables more precise and cheaper dataflow
1698
       analysis and makes writing interprocedural optimizations easier.
1699
       The following improvements have been implemented on top of this
1700
       framework:
1701
          + Pre-inline optimization: Selected local optimization passes
1702
            are run before the inliner (and other interprocedural passes)
1703
            are executed. This significantly improves the accuracy of code
1704
            growth estimates used by the inliner and reduces the overall
1705
            memory footprint for large compilation units.
1706
          + Early inlining (a simple bottom-up inliner pass inlining only
1707
            functions whose body is smaller than the expected call
1708
            overhead) is now executed with the early optimization passes,
1709
            thus inlining already optimized function bodies into an
1710
            unoptimized function that is subsequently optimized by early
1711
            optimizers. This enables the compiler to quickly eliminate
1712
            abstraction penalty in C++ programs.
1713
          + Interprocedural constant propagation now operate on SSA form
1714
            increasing accuracy of the analysis.
1715
     * A new internal representation for GIMPLE statements has been
1716
       contributed, resulting in compile-time memory savings.
1717
     * The vectorizer was enhanced to support vectorization of outer
1718
       loops, intra-iteration parallelism (loop-aware SLP), vectorization
1719
       of strided accesses and loops with multiple data-types. Run-time
1720
       dependency testing using loop versioning was added. The cost model,
1721
       turned on by -fvect-cost-model, was developed.
1722
 
1723
New Languages and Language specific improvements
1724
 
1725
     * We have added new command-line options
1726
       -finstrument-functions-exclude-function-list and
1727
       -finstrument-functions-exclude-file-list. They provide more control
1728
       over which functions are annotated by the -finstrument-functions
1729
       option.
1730
 
1731
  C family
1732
 
1733
     * Implicit conversions between generic vector types are now only
1734
       permitted when the two vectors in question have the same number of
1735
       elements and compatible element types. (Note that the restriction
1736
       involves compatible element types, not implicitly-convertible
1737
       element types: thus, a vector type with element type int may not be
1738
       implicitly converted to a vector type with element type unsigned
1739
       int.) This restriction, which is in line with specifications for
1740
       SIMD architectures such as AltiVec, may be relaxed using the flag
1741
       -flax-vector-conversions. This flag is intended only as a
1742
       compatibility measure and should not be used for new code.
1743
     * -Warray-bounds has been added and is now enabled by default for
1744
       -Wall . It produces warnings for array subscripts that can be
1745
       determined at compile time to be always out of bounds.
1746
       -Wno-array-bounds will disable the warning.
1747
     * The constructor and destructor function attributes now accept
1748
       optional priority arguments which control the order in which the
1749
       constructor and destructor functions are run.
1750
     * New [11]command-line options -Wtype-limits,
1751
       -Wold-style-declaration, -Wmissing-parameter-type, -Wempty-body,
1752
       -Wclobbered and -Wignored-qualifiers have been added for finer
1753
       control of the diverse warnings enabled by -Wextra.
1754
     * A new function attribute alloc_size has been added to mark up
1755
       malloc style functions. For constant sized allocations this can be
1756
       used to find out the size of the returned pointer using the
1757
       __builtin_object_size() function for buffer overflow checking and
1758
       similar. This supplements the already built-in malloc and calloc
1759
       constant size handling.
1760
     * Integer constants written in binary are now supported as a GCC
1761
       extension. They consist of a prefix 0b or 0B, followed by a
1762
       sequence of 0 and 1 digits.
1763
     * A new predefined macro __COUNTER__ has been added. It expands to
1764
       sequential integral values starting from 0. In conjunction with the
1765
       ## operator, this provides a convenient means to generate unique
1766
       identifiers.
1767
     * A new command-line option -fdirectives-only has been added. It
1768
       enables a special preprocessing mode which improves the performance
1769
       of applications like distcc and ccache.
1770
     * Fixed-point data types and operators have been added. They are
1771
       based on Chapter 4 of the Embedded-C specification (n1169.pdf).
1772
       Currently, only MIPS targets are supported.
1773
     * Decimal floating-point arithmetic based on draft ISO/IEC TR 24732,
1774
       N1241, is now supported as a GCC extension to C for targets
1775
       i[34567]86-*-linux-gnu, powerpc*-*-linux-gnu, s390*-ibm-linux-gnu,
1776
       and x86_64-*-linux-gnu. The feature introduces new data types
1777
       _Decimal32, _Decimal64, and _Decimal128 with constant suffixes DF,
1778
       DD, and DL.
1779
 
1780
  C++
1781
 
1782
     * [12]Experimental support for the upcoming ISO C++ standard, C++0x.
1783
     * -Wc++0x-compat has been added and is now enabled by default for
1784
       -Wall. It produces warnings for constructs whose meaning differs
1785
       between ISO C++ 1998 and C++0x.
1786
     * The -Wparentheses option now works for C++ as it does for C. It
1787
       warns if parentheses are omitted when operators with confusing
1788
       precedence are nested. It also warns about ambiguous else
1789
       statements. Since -Wparentheses is enabled by -Wall, this may cause
1790
       additional warnings with existing C++ code which uses -Wall. These
1791
       new warnings may be disabled by using -Wall -Wno-parentheses.
1792
     * The -Wmissing-declarations now works for C++ as it does for C.
1793
     * The -fvisibility-ms-compat flag was added, to make it easier to
1794
       port larger projects using shared libraries from Microsoft's Visual
1795
       Studio to ELF and Mach-O systems.
1796
     * C++ attribute handling has been overhauled for template arguments
1797
       (ie dependent types). In particular, __attribute__((aligned(T)));
1798
       works for C++ types.
1799
 
1800
    Runtime Library (libstdc++)
1801
 
1802
     * [13]Experimental support for the upcoming ISO C++ standard, C++0x.
1803
     * Support for TR1 mathematical special functions and regular
1804
       expressions. ([14]Implementation status of TR1)
1805
     * Default what implementations give more elaborate exception strings
1806
       for bad_cast, bad_typeid, bad_exception, and bad_alloc.
1807
     * Header dependencies have been streamlined, reducing unnecessary
1808
       includes and pre-processed bloat.
1809
     * Variadic template implementations of items in  and
1810
       .
1811
     * An experimental [15]parallel mode has been added. This is a
1812
       parallel implementation of many C++ Standard library algorithms,
1813
       like std::accumulate, std::for_each, std::transform, or std::sort,
1814
       to give but four examples. These algorithms can be substituted for
1815
       the normal (sequential) libstdc++ algorithms on a piecemeal basis,
1816
       or all existing algorithms can be transformed via the
1817
       -D_GLIBCXX_PARALLEL macro.
1818
     * Debug mode versions of classes in  and
1819
       .
1820
     * Formal deprecation of  and , which are
1821
       now  and . This code:
1822
    #include 
1823
    __gnu_cxx::hash_set s;
1824
 
1825
       Can be transformed (in order of preference) to:
1826
    #include 
1827
    std::tr1::unordered_set s;
1828
 
1829
       or
1830
    #include 
1831
    __gnu_cxx::hash_set s;
1832
 
1833
       Similar transformations apply to __gnu_cxx::hash_map,
1834
       __gnu_cxx::hash_multimap, __gnu_cxx::hash_set,
1835
       __gnu_cxx::hash_multiset.
1836
 
1837
  Fortran
1838
 
1839
     * Due to the fact that the [16]GMP and [17]MPFR libraries are
1840
       required for all languages, Fortran is no longer special in this
1841
       regard and is available by default.
1842
     * The [18]-fexternal-blas option has been added, which generates
1843
       calls to BLAS routines for intrinsic matrix operations such as
1844
       matmul rather than using the built-in algorithms.
1845
     * Support to give a backtrace (compiler flag -fbacktrace or
1846
       environment variable GFORTRAN_ERROR_BACKTRACE; on glibc systems
1847
       only) or a core dump (-fdump-core, GFORTRAN_ERROR_DUMPCORE) when a
1848
       run-time error occured.
1849
     * GNU Fortran now defines __GFORTRAN__ when it runs the C
1850
       preprocessor (CPP).
1851
     * The [19]-finit-local-zero, -finit-real, -finit-integer,
1852
       -finit-character, and -finit-logical options have been added, which
1853
       can be used to initialize local variables.
1854
     * The intrinsic procedures [20]GAMMA and [21]LGAMMA have been added,
1855
       which calculate the Gamma function and its logarithm. Use EXTERNAL
1856
       gamma if you want to use your own gamma function.
1857
     * GNU Fortran now regards the backslash character as literal (as
1858
       required by the Fortran 2003 standard); using [22]-fbackslash GNU
1859
       Fortran interprets backslashes as C-style escape characters.
1860
     * The [23]interpretation of binary, octal and hexadecimal (BOZ)
1861
       literal constants has been changed. Before they were always
1862
       interpreted as integer; now they are bit-wise transferred as
1863
       argument of INT, REAL, DBLE and CMPLX as required by the Fortran
1864
       2003 standard, and for real and complex variables in DATA
1865
       statements or when directly assigned to real and complex variables.
1866
       Everywhere else and especially in expressions they are still
1867
       regarded as integer constants.
1868
     * Fortran 2003 support has been extended:
1869
          + Intrinsic statements IMPORT, PROTECTED, VALUE and VOLATILE
1870
          + Pointer intent
1871
          + Intrinsic module ISO_ENV_FORTRAN
1872
          + Interoperability with C (ISO C Bindings)
1873
          + ABSTRACT INTERFACES and PROCEDURE statements (without POINTER
1874
            attribute)
1875
          + Fortran 2003 BOZ
1876
 
1877
  Java (GCJ)
1878
 
1879
     * GCJ now uses the Eclipse Java compiler for its Java parsing needs.
1880
       This enables the use of all 1.5 language features, and fixes most
1881
       existing front end bugs.
1882
     * libgcj now supports all 1.5 language features which require runtime
1883
       support: foreach, enum, annotations, generics, and auto-boxing.
1884
     * We've made many changes to the tools shipped with gcj.
1885
          + The old jv-scan tool has been removed. This tool never really
1886
            worked properly. There is no replacement.
1887
          + gcjh has been rewritten. Some of its more obscure options no
1888
            longer work, but are still recognized in an attempt at
1889
            compatibility. gjavah is a new program with similar
1890
            functionality but different command-line options.
1891
          + grmic and grmiregistry have been rewritten. grmid has been
1892
            added.
1893
          + gjar replaces the old fastjar.
1894
          + gjarsigner (used for signing jars), gkeytool (used for key
1895
            management), gorbd (for CORBA), gserialver (computes
1896
            serialization UIDs), and gtnameserv (also for CORBA) are now
1897
            installed.
1898
     * The ability to dump the contents of the java run time heap to a
1899
       file for off-line analysis has been added. The heap dumps may be
1900
       analyzed with the new gc-analyze tool. They may be generated on
1901
       out-of-memory conditions or on demand and are controlled by the new
1902
       run time class gnu.gcj.util.GCInfo.
1903
     * java.util.TimeZone can now read files from /usr/share/zoneinfo to
1904
       provide correct, updated, timezone information. This means that
1905
       packagers no longer have to update libgcj when a time zone change
1906
       is published.
1907
 
1908
New Targets and Target Specific Improvements
1909
 
1910
  IA-32/x86-64
1911
 
1912
     * Tuning for Intel Core 2 processors is available via -mtune=core2
1913
       and -march=core2.
1914
     * Tuning for AMD Geode processors is available via -mtune=geode and
1915
       -march=geode.
1916
     * Code generation of block move (memcpy) and block set (memset) was
1917
       rewritten. GCC can now pick the best algorithm (loop, unrolled
1918
       loop, instruction with rep prefix or a library call) based on the
1919
       size of the block being copied and the CPU being optimized for. A
1920
       new option -minline-stringops-dynamically has been added. With this
1921
       option string operations of unknown size are expanded such that
1922
       small blocks are copied by in-line code, while for large blocks a
1923
       library call is used. This results in faster code than
1924
       -minline-all-stringops when the library implementation is capable
1925
       of using cache hierarchy hints. The heuristic choosing the
1926
       particular algorithm can be overwritten via -mstringop-strategy.
1927
       Newly also memset of values different from 0 is inlined.
1928
     * GCC no longer places the cld instruction before string operations.
1929
       Both i386 and x86-64 ABI documents mandate the direction flag to be
1930
       clear at the entry of a function. It is now invalid to set the flag
1931
       in asm statement without reseting it afterward.
1932
     * Support for SSSE3 built-in functions and code generation are
1933
       available via -mssse3.
1934
     * Support for SSE4.1 built-in functions and code generation are
1935
       available via -msse4.1.
1936
     * Support for SSE4.2 built-in functions and code generation are
1937
       available via -msse4.2.
1938
     * Both SSE4.1 and SSE4.2 support can be enabled via -msse4.
1939
     * A new set of options -mpc32, -mpc64 and -mpc80 have been added to
1940
       allow explicit control of x87 floating point precision.
1941
     * Support for __float128 (TFmode) IEEE quad type and corresponding
1942
       TCmode IEEE complex quad type is available via the soft-fp library
1943
       on x86_64 targets. This includes basic arithmetic operations
1944
       (addition, subtraction, negation, multiplication and division) on
1945
       __float128 real and TCmode complex values, the full set of IEEE
1946
       comparisons between __float128 values, conversions to and from
1947
       float, double and long double floating point types, as well as
1948
       conversions to and from signed or unsigned integer, signed or
1949
       unsigned long integer and signed or unsigned quad (TImode) integer
1950
       types. Additionally, all operations generate the full set of IEEE
1951
       exceptions and support the full set of IEEE rounding modes.
1952
     * GCC can now utilize the ACML library for vectorizing calls to a set
1953
       of C99 functions on x86_64 if -mveclibabi=acml is specified and you
1954
       link to an ACML ABI compatible library.
1955
 
1956
  ARM
1957
 
1958
     * Compiler and Library support for Thumb-2 and the ARMv7 architecture
1959
       has been added.
1960
 
1961
  CRIS
1962
 
1963
    New features
1964
 
1965
     * Compiler and Library support for the CRIS v32 architecture, as
1966
       found in Axis Communications ETRAX FS and ARTPEC-3 chips, has been
1967
       added.
1968
 
1969
    Configuration changes
1970
 
1971
     * The cris-*-elf target now includes support for CRIS v32, including
1972
       libraries, through the -march=v32 option.
1973
     * A new crisv32-*-elf target defaults to generate code for CRIS v32.
1974
     * A new crisv32-*-linux* target defaults to generate code for CRIS
1975
       v32.
1976
     * The cris-*-aout target has been obsoleted.
1977
 
1978
    Improved support for built-in functions
1979
 
1980
     * GCC can now use the lz and swapwbr instructions to implement the
1981
       __builtin_clz, __builtin_ctz and __builtin_ffs family of functions.
1982
     * __builtin_bswap32 is now implemented using the swapwb instruction,
1983
       when available.
1984
 
1985
  m68k and ColdFire
1986
 
1987
    New features
1988
 
1989
     * Support for several new ColdFire processors has been added. You can
1990
       generate code for them using the new -mcpu option.
1991
     * All targets now support ColdFire processors.
1992
     * m68k-uclinux targets have improved support for C++ constructors and
1993
       destructors, and for shared libraries.
1994
     * It is now possible to set breakpoints on the first or last line of
1995
       a function, even if there are no statements on that line.
1996
 
1997
    Optimizations
1998
 
1999
     * Support for sibling calls has been added.
2000
     * More use is now made of the ColdFire mov3q instruction.
2001
     * __builtin_clz is now implemented using the ff1 ColdFire
2002
       instruction, when available.
2003
     * GCC now honors the -m68010 option. 68010 code now uses clr rather
2004
       than move to zero volatile memory.
2005
     * 68020 targets and above can now use symbol(index.size*scale)
2006
       addresses for indexed array accesses. Earlier compilers would
2007
       always load the symbol into a base register first.
2008
 
2009
    Configuration changes
2010
 
2011
     * All m68k and ColdFire targets now allow the default processor to be
2012
       set at configure time using --with-cpu.
2013
     * A --with-arch configuration option has been added. This option
2014
       allows you to restrict a target to ColdFire or non-ColdFire
2015
       processors.
2016
 
2017
    Preprocessor macros
2018
 
2019
     * An __mcfv*__ macro is now defined for all ColdFire targets.
2020
       (Earlier versions of GCC only defined __mcfv4e__.)
2021
     * __mcf_cpu_*, __mcf_family_* and __mcffpu__ macros have been added.
2022
     * All targets now define __mc68010 and __mc68010__ when generating
2023
       68010 code.
2024
 
2025
    Command-line changes
2026
 
2027
     * New command-line options -march, -mcpu, -mtune and -mhard-float
2028
       have been added. These options apply to both m68k and ColdFire
2029
       targets.
2030
     * -mno-short, -mno-bitfield and -mno-rtd are now accepted as negative
2031
       versions of -mshort, etc.
2032
     * -fforce-addr has been removed. It is now ignored by the compiler.
2033
 
2034
    Other improvements
2035
 
2036
     * ColdFire targets now try to maintain a 4-byte-aligned stack where
2037
       possible.
2038
     * m68k-uclinux targets now try to avoid situations that lead to the
2039
       load-time error: BINFMT_FLAT: reloc outside program.
2040
 
2041
  MIPS
2042
 
2043
    Changes to existing configurations
2044
 
2045
     * libffi and libjava now support all three GNU/Linux ABIs: o32, n32
2046
       and n64. Every GNU/Linux configuration now builds these libraries
2047
       by default.
2048
     * GNU/Linux configurations now generate -mno-shared code unless
2049
       overridden by -fpic, -fPIC, -fpie or -fPIE.
2050
     * mipsisa32*-linux-gnu configurations now generate hard-float code by
2051
       default, just like other mipsisa32* and mips*-linux-gnu
2052
       configurations. You can build a soft-float version of any
2053
       mips*-linux-gnu configuration by passing --with-float=soft to
2054
       configure.
2055
     * mips-wrs-vxworks now supports run-time processes (RTPs).
2056
 
2057
    Changes to existing command-line options
2058
 
2059
     * The -march and -mtune options no longer accept 24k as a processor
2060
       name. Please use 24kc, 24kf2_1 or 24kf1_1 instead.
2061
     * The -march and -mtune options now accept 24kf2_1, 24kef2_1 and
2062
       34kf2_1 as synonyms for 24kf, 24kef and 34kf respectively. The
2063
       options also accept 24kf1_1, 24kef1_1 and 34kf1_1 as synonyms for
2064
       24kx, 24kex and 34kx.
2065
 
2066
    New configurations
2067
 
2068
   GCC now supports the following configurations:
2069
     * mipsisa32r2*-linux-gnu*, which generates MIPS32 revision 2 code by
2070
       default. Earlier releases also recognized this configuration, but
2071
       they treated it in the same way as mipsisa32*-linux-gnu*. Note that
2072
       you can customize any mips*-linux-gnu* configuration to a
2073
       particular ISA or processor by passing an appropriate --with-arch
2074
       option to configure.
2075
     * mipsisa*-sde-elf*, which provides compatibility with MIPS
2076
       Technologies' SDE toolchains. The configuration uses the SDE
2077
       libraries by default, but you can use it like other newlib-based
2078
       ELF configurations by passing --with-newlib to configure. It is the
2079
       only configuration besides mips64vr*-elf* to build MIPS16 as well
2080
       as non-MIPS16 libraries.
2081
     * mipsisa*-elfoabi*, which is similar to the general mipsisa*-elf*
2082
       configuration, but uses the o32 and o64 ABIs instead of the 32-bit
2083
       and 64-bit forms of the EABI.
2084
 
2085
    New processors and application-specific extensions
2086
 
2087
     * Support for the SmartMIPS ASE is available through the new
2088
       -msmartmips option.
2089
     * Support for revision 2 of the DSP ASE is available through the new
2090
       -mdspr2 option. A new preprocessor macro called __mips_dsp_rev
2091
       indicates the revision of the ASE in use.
2092
     * Support for the 4KS and 74K families of processors is available
2093
       through the -march and -mtune options.
2094
 
2095
    Improved support for built-in functions
2096
 
2097
     * GCC can now use load-linked, store-conditional and sync
2098
       instructions to implement atomic built-in functions such as
2099
       __sync_fetch_and_add. The memory reference must be 4 bytes wide for
2100
       32-bit targets and either 4 or 8 bytes wide for 64-bit targets.
2101
     * GCC can now use the clz and dclz instructions to implement the
2102
       __builtin_ctz and __builtin_ffs families of functions.
2103
     * There is a new __builtin___clear_cache function for flushing the
2104
       instruction cache. GCC expands this function inline on MIPS32
2105
       revision 2 targets, otherwise it calls the function specified by
2106
       -mcache-flush-func.
2107
 
2108
    MIPS16 improvements
2109
 
2110
     * GCC can now compile objects that contain a mixture of MIPS16 and
2111
       non-MIPS16 code. There are two new attributes, mips16 and nomips16,
2112
       for specifying which mode a function should use.
2113
     * A new option called -minterlink-mips16 makes non-MIPS16 code
2114
       link-compatible with MIPS16 code.
2115
     * After many bug fixes, the long-standing MIPS16 -mhard-float support
2116
       should now work fairly reliably.
2117
     * GCC can now use the MIPS16e save and restore instructions.
2118
     * -fsection-anchors now works in MIPS16 mode. MIPS16 code compiled
2119
       with -G0 -fsection-anchors is often smaller than code compiled with
2120
       -G8. However, please note that you must usually compile all objects
2121
       in your application with the same -G option; see the documentation
2122
       of -G for details.
2123
     * A new option called-mcode-readable specifies which instructions are
2124
       allowed to load from the code segment. -mcode-readable=yes is the
2125
       default and says that any instruction may load from the code
2126
       segment. The other alternatives are -mcode-readable=pcrel, which
2127
       says that only PC-relative MIPS16 instructions may load from the
2128
       code segment, and -mcode-readable=no, which says that no
2129
       instruction may do so. Please see the documentation for more
2130
       details, including example uses.
2131
 
2132
    Small-data improvements
2133
 
2134
   There are three new options for controlling small data:
2135
     * -mno-extern-sdata, which disables small-data accesses for
2136
       externally-defined variables. Code compiled with -Gn
2137
       -mno-extern-sdata will be link-compatible with any -G setting
2138
       between -G0 and -Gn inclusive.
2139
     * -mno-local-sdata, which disables the use of small-data sections for
2140
       data that is not externally visible. This option can be a useful
2141
       way of reducing small-data usage in less performance-critical parts
2142
       of an application.
2143
     * -mno-gpopt, which disables the use of the $gp register while still
2144
       honoring the -G limit when placing externally-visible data. This
2145
       option implies -mno-extern-sdata and -mno-local-sdata and it can be
2146
       useful in situations where $gp does not necessarily hold the
2147
       expected value.
2148
 
2149
    Miscellaneous improvements
2150
 
2151
     * There is a new option called -mbranch-cost for tweaking the
2152
       perceived cost of branches.
2153
     * If GCC is configured to use a version of GAS that supports the
2154
       .gnu_attribute directive, it will use that directive to record
2155
       certain properties of the output code. .gnu_attribute is new to GAS
2156
       2.18.
2157
     * There are two new function attributes, near and far, for overriding
2158
       the command-line setting of -mlong-calls on a function-by-function
2159
       basis.
2160
     * -mfp64, which previously required a 64-bit target, now works with
2161
       MIPS32 revision 2 targets as well. The mipsisa*-elfoabi* and
2162
       mipsisa*-sde-elf* configurations provide suitable library support.
2163
     * GCC now recognizes the -mdmx and -mmt options and passes them down
2164
       to the assembler. It does nothing else with the options at present.
2165
 
2166
  SPU (Synergistic Processor Unit) of the Cell Broadband Engine Architecture
2167
  (BEA)
2168
 
2169
     * Support has been added for this new architecture.
2170
 
2171
  RS6000 (POWER/PowerPC)
2172
 
2173
     * Support for the PowerPC 750CL paired-single instructions has been
2174
       added with a new powerpc-*-linux*paired* target configuration. It
2175
       is enabled by an associated -mpaired option and can be accessed
2176
       using new built-in functions.
2177
     * Support for auto-detecting architecture and system configuration to
2178
       auto-select processor optimization tuning.
2179
     * Support for VMX on AIX 5.3 has been added.
2180
     * Support for AIX Version 6.1 has been added.
2181
 
2182
  S/390, zSeries and System z9
2183
 
2184
     * Support for the IBM System z9 EC/BC processor (z9 GA3) has been
2185
       added. When using the -march=z9-ec option, the compiler will
2186
       generate code making use of instructions provided by the decimal
2187
       floating point facility and the floating point conversion facility
2188
       (pfpo). Besides the instructions used to implement decimal floating
2189
       point operations these facilities also contain instructions to move
2190
       between general purpose and floating point registers and to modify
2191
       and copy the sign-bit of floating point values.
2192
     * When the -march=z9-ec option is used the new
2193
       -mhard-dfp/-mno-hard-dfp options can be used to specify whether the
2194
       decimal floating point hardware instructions will be used or not.
2195
       If none of them is given the hardware support is enabled by
2196
       default.
2197
     * The -mstack-guard option can now be omitted when using stack
2198
       checking via -mstack-size in order to let GCC choose a sensible
2199
       stack guard value according to the frame size of each function.
2200
     * Various changes to improve performance of generated code have been
2201
       implemented, including:
2202
          + The condition code set by an add logical with carry
2203
            instruction is now available for overflow checks like: a + b +
2204
            carry < b.
2205
          + The test data class instruction is now used to implement
2206
            sign-bit and infinity checks of binary and decimal floating
2207
            point numbers.
2208
 
2209
  Xtensa
2210
 
2211
     * Stack unwinding for exception handling now uses by default a
2212
       specialized version of DWARF unwinding. This is not
2213
       binary-compatible with the setjmp/longjmp (sjlj) unwinding used for
2214
       Xtensa with previous versions of GCC.
2215
     * For Xtensa processors that include the Conditional Store option,
2216
       the built-in functions for atomic memory access are now implemented
2217
       using S32C1I instructions.
2218
     * If the Xtensa NSA option is available, GCC will use it to implement
2219
       the __builtin_ctz and __builtin_clz functions.
2220
 
2221
Documentation improvements
2222
 
2223
     * Existing libstdc++ documentation has been edited and restructured
2224
       into a single DocBook XML manual. The results can be viewed online
2225
       [24]here.
2226
 
2227
Other significant improvements
2228
 
2229
     * The compiler's --help command-line option has been extended so that
2230
       it now takes an optional set of arguments. These arguments restrict
2231
       the information displayed to specific classes of command-line
2232
       options, and possibly only a subset of those options. It is also
2233
       now possible to replace the descriptive text associated with each
2234
       displayed option with an indication of its current value, or for
2235
       binary options, whether it has been enabled or disabled.
2236
       Here are some examples. The following will display all the options
2237
       controlling warning messages:
2238
      --help=warnings
2239
 
2240
       Whereas this will display all the undocumented, target specific
2241
       options:
2242
      --help=target,undocumented
2243
 
2244
       This sequence of commands will display the binary optimizations
2245
       that are enabled by -O3:
2246
      gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
2247
      gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
2248
      diff /tmp/O2-opts /tmp/O3-opts | grep enabled
2249
 
2250
     * The configure options --with-pkgversion and --with-bugurl have been
2251
       added. These allow distributors of GCC to include a
2252
       distributor-specific string in manuals and --version output and to
2253
       specify the URL for reporting bugs in their versions of GCC.
2254
 
2255
GCC 4.3.1
2256
 
2257
   This is the [25]list of problem reports (PRs) from GCC's bug tracking
2258
   system that are known to be fixed in the 4.3.1 release. This list might
2259
   not be complete (that is, it is possible that some PRs that have been
2260
   fixed are not listed here).
2261
 
2262
Target Specific Changes
2263
 
2264
  IA-32/x86-64
2265
 
2266
    ABI changes
2267
 
2268
     * Starting with GCC 4.3.1, decimal floating point variables are
2269
       aligned to their natural boundaries when they are passed on the
2270
       stack for i386.
2271
 
2272
    Command-line changes
2273
 
2274
     * Starting with GCC 4.3.1, the -mcld option has been added to
2275
       automatically generate a cld instruction in the prologue of
2276
       functions that use string instructions. This option is used for
2277
       backward compatibility on some operating systems and can be enabled
2278
       by default for 32-bit x86 targets by configuring GCC with the
2279
       --enable-cld configure option.
2280
 
2281
GCC 4.3.2
2282
 
2283
   This is the [26]list of problem reports (PRs) from GCC's bug tracking
2284
   system that are known to be fixed in the 4.3.2 release. This list might
2285
   not be complete (that is, it is possible that some PRs that have been
2286
   fixed are not listed here).
2287
 
2288
GCC 4.3.3
2289
 
2290
   This is the [27]list of problem reports (PRs) from GCC's bug tracking
2291
   system that are known to be fixed in the 4.3.3 release. This list might
2292
   not be complete (that is, it is possible that some PRs that have been
2293
   fixed are not listed here).
2294
 
2295
GCC 4.3.4
2296
 
2297
   This is the [28]list of problem reports (PRs) from GCC's bug tracking
2298
   system that are known to be fixed in the 4.3.4 release. This list might
2299
   not be complete (that is, it is possible that some PRs that have been
2300
   fixed are not listed here).
2301
 
2302
GCC 4.3.5
2303
 
2304
   This is the [29]list of problem reports (PRs) from GCC's bug tracking
2305
   system that are known to be fixed in the 4.3.5 release. This list might
2306
   not be complete (that is, it is possible that some PRs that have been
2307
   fixed are not listed here).
2308
 
2309
   Please send FSF & GNU inquiries & questions to [30]gnu@gnu.org. There
2310
   are also [31]other ways to contact the FSF.
2311
 
2312
   These pages are [32]maintained by the GCC team.
2313
 
2314
 
2315
    For questions related to the use of GCC, please consult these web
2316
    pages and the [33]GCC manuals. If that fails, the
2317
    [34]gcc-help@gcc.gnu.org mailing list might help.
2318
    Please send comments on these web pages and the development of GCC to
2319
    our developer mailing list at [35]gcc@gnu.org or [36]gcc@gcc.gnu.org.
2320
    All of our lists have [37]public archives.
2321
 
2322
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
2323
   Floor, Boston, MA 02110, USA.
2324
 
2325
   Verbatim copying and distribution of this entire article is permitted
2326
   in any medium, provided this notice is preserved.
2327
   Last modified 2010-07-10 [38]Valid XHTML 1.0
2328
 
2329
References
2330
 
2331
   1. http://gcc.gnu.org/gcc-4.3/changes.html#4.3.5
2332
   2. http://gmplib.org/
2333
   3. http://www.mpfr.org/
2334
   4. http://gcc.gnu.org/install/prerequisites.html
2335
   5. http://gcc.gnu.org/ml/gcc-announce/2001/msg00000.html
2336
   6. http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options
2337
   7. http://gcc.gnu.org/gcc-4.3/porting_to.html
2338
   8. http://www.mpfr.org/
2339
   9. http://www.mpfr.org/
2340
  10. http://www.mpfr.org/
2341
  11. http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
2342
  12. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
2343
  13. http://gcc.gnu.org/gcc-4.3/cxx0x_status.html
2344
  14. http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#m anual.intro.status.standard.tr1
2345
  15. http://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html
2346
  16. http://gmplib.org/
2347
  17. http://www.mpfr.org/
2348
  18. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#Code-Gen-Options
2349
  19. http://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfinit-local-zero_007d-167
2350
  20. http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/GAMMA.html
2351
  21. http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gfortran/LGAMMA.html
2352
  22. http://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html
2353
  23. http://gcc.gnu.org/onlinedocs/gfortran/BOZ-literal-constants.html
2354
  24. http://gcc.gnu.org/onlinedocs/libstdc++/
2355
  25. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.1
2356
  26. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.2
2357
  27. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.3
2358
  28. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.4
2359
  29. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.3.5
2360
  30. mailto:gnu@gnu.org
2361
  31. http://www.gnu.org/home.html#ContactInfo
2362
  32. http://gcc.gnu.org/about.html
2363
  33. http://gcc.gnu.org/onlinedocs/
2364
  34. mailto:gcc-help@gcc.gnu.org
2365
  35. mailto:gcc@gnu.org
2366
  36. mailto:gcc@gcc.gnu.org
2367
  37. http://gcc.gnu.org/lists.html
2368
  38. http://validator.w3.org/check/referer
2369
======================================================================
2370
http://gcc.gnu.org/gcc-4.2/index.html
2371
 
2372
                           GCC 4.2 Release Series
2373
 
2374
   May 19, 2008
2375
 
2376
   The [1]GNU project and the GCC developers are pleased to announce the
2377
   release of GCC 4.2.4.
2378
 
2379
   This release is a bug-fix release, containing fixes for regressions in
2380
   GCC 4.2.3 relative to previous releases of GCC.
2381
 
2382
Release History
2383
 
2384
   GCC 4.2.4
2385
          May 19, 2008 ([2]changes)
2386
 
2387
   GCC 4.2.3
2388
          February 1, 2008 ([3]changes)
2389
 
2390
   GCC 4.2.2
2391
          October 7, 2007 ([4]changes)
2392
 
2393
   GCC 4.2.1
2394
          July 18, 2007 ([5]changes)
2395
 
2396
   GCC 4.2.0
2397
          May 13, 2007 ([6]changes)
2398
 
2399
References and Acknowledgements
2400
 
2401
   GCC used to stand for the GNU C Compiler, but since the compiler
2402
   supports several other languages aside from C, it now stands for the
2403
   GNU Compiler Collection.
2404
 
2405
   A list of [7]successful builds is updated as new information becomes
2406
   available.
2407
 
2408
   The GCC developers would like to thank the numerous people that have
2409
   contributed new features, improvements, bug fixes, and other changes as
2410
   well as test results to GCC. This [8]amazing group of volunteers is
2411
   what makes GCC successful.
2412
 
2413
   For additional information about GCC please refer to the [9]GCC project
2414
   web site or contact the [10]GCC development mailing list.
2415
 
2416
   To obtain GCC please use [11]our mirror sites or [12]our SVN server.
2417
 
2418
   Please send FSF & GNU inquiries & questions to [13]gnu@gnu.org. There
2419
   are also [14]other ways to contact the FSF.
2420
 
2421
   These pages are [15]maintained by the GCC team.
2422
 
2423
 
2424
    For questions related to the use of GCC, please consult these web
2425
    pages and the [16]GCC manuals. If that fails, the
2426
    [17]gcc-help@gcc.gnu.org mailing list might help.
2427
    Please send comments on these web pages and the development of GCC to
2428
    our developer mailing list at [18]gcc@gnu.org or [19]gcc@gcc.gnu.org.
2429
    All of our lists have [20]public archives.
2430
 
2431
   Copyright (C) Free Software Foundation, Inc., 51 Franklin St, Fifth
2432
   Floor, Boston, MA 02110, USA.
2433
 
2434
   Verbatim copying and distribution of this entire article is permitted
2435
   in any medium, provided this notice is preserved.
2436
   Last modified 2010-07-01 [21]Valid XHTML 1.0
2437
 
2438
References
2439
 
2440
   1. http://www.gnu.org/
2441
   2. http://gcc.gnu.org/gcc-4.2/changes.html
2442
   3. http://gcc.gnu.org/gcc-4.2/changes.html
2443
   4. http://gcc.gnu.org/gcc-4.2/changes.html
2444
   5. http://gcc.gnu.org/gcc-4.2/changes.html
2445
   6. http://gcc.gnu.org/gcc-4.2/changes.html
2446
   7. http://gcc.gnu.org/gcc-4.2/buildstat.html
2447
   8. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
2448
   9. http://gcc.gnu.org/index.html
2449
  10. mailto:gcc@gcc.gnu.org
2450
  11. http://gcc.gnu.org/mirrors.html
2451
  12. http://gcc.gnu.org/svn.html
2452
  13. mailto:gnu@gnu.org
2453
  14. http://www.gnu.org/home.html#ContactInfo
2454
  15. http://gcc.gnu.org/about.html
2455
  16. http://gcc.gnu.org/onlinedocs/
2456
  17. mailto:gcc-help@gcc.gnu.org
2457
  18. mailto:gcc@gnu.org
2458
  19. mailto:gcc@gcc.gnu.org
2459
  20. http://gcc.gnu.org/lists.html
2460
  21. http://validator.w3.org/check/referer
2461
======================================================================
2462
http://gcc.gnu.org/gcc-4.2/changes.html
2463
 
2464
                           GCC 4.2 Release Series
2465
                      Changes, New Features, and Fixes
2466
 
2467
Caveats
2468
 
2469
     * GCC no longer accepts the -fshared-data option. This option has had
2470
       no effect in any GCC 4 release; the targets to which the option
2471
       used to apply had been removed before GCC 4.0.
2472
 
2473
General Optimizer Improvements
2474
 
2475
     * New command-line options specify the possible relationships among
2476
       parameters and between parameters and global data. For example,
2477
       -fargument-noalias-anything specifies that arguments do not alias
2478
       any other storage.
2479
       Each language will automatically use whatever option is required by
2480
       the language standard. You should not need to use these options
2481
       yourself.
2482
 
2483
New Languages and Language specific improvements
2484
 
2485
     * [1]OpenMP is now supported for the C, C++ and Fortran compilers.
2486
     * New command-line options -fstrict-overflow and -Wstrict-overflow
2487
       have been added. -fstrict-overflow tells the compiler that it may
2488
       assume that the program follows the strict signed overflow
2489
       semantics permitted for the language: for C and C++ this means that
2490
       the compiler may assume that signed overflow does not occur. For
2491
       example, a loop like
2492
      for (i = 1; i > 0; i *= 2)
2493
 
2494
       is presumably intended to continue looping until i overflows. With
2495
       -fstrict-overflow, the compiler may assume that signed overflow
2496
       will not occur, and transform this into an infinite loop.
2497
       -fstrict-overflow is turned on by default at -O2, and may be
2498
       disabled via -fno-strict-overflow. The -Wstrict-overflow option may
2499
       be used to warn about cases where the compiler assumes that signed
2500
       overflow will not occur. It takes five different levels:
2501
       -Wstrict-overflow=1 to 5. See the [2]documentation for details.
2502
       -Wstrict-overflow=1 is enabled by -Wall.
2503
     * The new command-line option -fno-toplevel-reorder directs GCC to
2504
       emit top-level functions, variables, and asm statements in the same
2505
       order that they appear in the input file. This is intended to
2506
       support existing code which relies on a particular ordering (for
2507
       example, code which uses top-level asm statements to switch
2508
       sections). For new code, it is generally better to use function and
2509
       variable attributes. The -fno-toplevel-reorder option may be used
2510
       for most cases which currently use -fno-unit-at-a-time. The
2511
       -fno-unit-at-a-time option will be removed in some future version
2512
       of GCC. If you know of a case which requires -fno-unit-at-a-time
2513
       which is not fixed by -fno-toplevel-reorder, please open a bug
2514
       report.
2515
 
2516
  C family
2517
 
2518
     * The pragma redefine_extname will now macro expand its tokens for
2519
       compatibility with SunPRO.
2520
     * In the next release of GCC, 4.3, -std=c99 or -std=gnu99 will direct
2521
       GCC to handle inline functions as specified in the C99 standard. In
2522
       preparation for this, GCC 4.2 will warn about any use of non-static
2523
       inline functions in gnu99 or c99 mode. This new warning may be
2524
       disabled with the new gnu_inline function attribute or the new
2525
       -fgnu89-inline command-line option. Also, GCC 4.2 and later will
2526
       define one of the preprocessor macros __GNUC_GNU_INLINE__ or
2527
       __GNUC_STDC_INLINE__ to indicate the semantics of inline functions
2528
       in the current compilation.
2529
     * A new command-line option -Waddress has been added to warn about
2530
       suspicious uses of memory addresses as, for example, using the
2531
       address of a function in a conditional expression, and comparisons
2532
       against the memory address of a string literal. This warning is
2533
       enabled by -Wall.
2534
 
2535
  C++
2536
 
2537
     * C++ visibility handling has been overhauled.
2538
       Restricted visiblity is propagated from classes to members, from
2539
       functions to local statics, and from templates and template
2540
       arguments to instantiations, unless the latter has explicitly
2541
       declared visibility.
2542
       The visibility attribute for a class must come between the
2543
       class-key and the name, not after the closing brace.
2544
       Attributes are now allowed for enums and elaborated-type-specifiers
2545
       that only declare a type.
2546
       Members of the anonymous namespace are now local to a particular
2547
       translation unit, along with any other declarations which use them,
2548
       though they are still treated as having external linkage for
2549
       language semantics.
2550
     * The (undocumented) extension which permitted templates with default
2551
       arguments to be bound to template template parameters with fewer
2552
       parameters has been removed. For example:
2553
        template