This file contains information about GCC releases which has been generated
automatically from the online release notes.  It covers releases of GCC
(and the former EGCS project) since EGCS 1.0, on the line of development
that led to GCC 3. For information on GCC 2.8.1 and older releases of GCC 2,
see ONEWS.

======================================================================
http://gcc.gnu.org/gcc-4.7/index.html

                             GCC 4.7 Release Series

   June 14, 2012

   The [1]GNU project and the GCC developers are pleased to announce the
   release of GCC 4.7.1.

   This release is a bug-fix release, containing fixes for regressions in
   GCC 4.7.0 relative to previous releases of GCC.

Release History

   GCC 4.7.1
          June 14, 2012 ([2]changes)

   GCC 4.7.0
          March 22, 2012 ([3]changes)

References and Acknowledgements

   GCC used to stand for the GNU C Compiler, but since the compiler
   supports several other languages aside from C, it now stands for the
   GNU Compiler Collection.

   A list of [4]successful builds is updated as new information becomes
   available.

   The GCC developers would like to thank the numerous people that have
   contributed new features, improvements, bug fixes, and other changes as
   well as test results to GCC. This [5]amazing group of volunteers is
   what makes GCC successful.

   For additional information about GCC please refer to the [6]GCC project
   web site or contact the [7]GCC development mailing list.

   To obtain GCC please use [8]our mirror sites or [9]our SVN server.


    For questions related to the use of GCC, please consult these web
    pages and the [10]GCC manuals. If that fails, the
    [11]gcc-help@gcc.gnu.org mailing list might help. Comments on these
    web pages and the development of GCC are welcome on our developer
    list at [12]gcc@gcc.gnu.org. All of [13]our lists have public
    archives.

   Copyright (C) [14]Free Software Foundation, Inc. Verbatim copying and
   distribution of this entire article is permitted in any medium,
   provided this notice is preserved.

   These pages are [15]maintained by the GCC team. Last modified
   2012-06-14[16].

References

   1. http://www.gnu.org/
   2. http://gcc.gnu.org/gcc-4.7/changes.html
   3. http://gcc.gnu.org/gcc-4.7/changes.html
   4. http://gcc.gnu.org/gcc-4.7/buildstat.html
   5. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   6. http://gcc.gnu.org/index.html
   7. mailto:gcc@gcc.gnu.org
   8. http://gcc.gnu.org/mirrors.html
   9. http://gcc.gnu.org/svn.html
  10. http://gcc.gnu.org/onlinedocs/
  11. mailto:gcc-help@gcc.gnu.org
  12. mailto:gcc@gcc.gnu.org
  13. http://gcc.gnu.org/lists.html
  14. http://www.fsf.org/
  15. http://gcc.gnu.org/about.html
  16. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.7/changes.html

                             GCC 4.7 Release Series
                        Changes, New Features, and Fixes

Caveats

     * The -fconserve-space flag has been deprecated. The flag had no
       effect for most targets: only targets without a global .bss section
       and without support for switchable sections. Furthermore, the flag
       only had an effect for G++, where it could result in wrong
       semantics (please refer to the GCC manual for further details). The
       flag will be removed in GCC 4.8
     * Support for a number of older systems and recently unmaintained or
       untested target ports of GCC has been declared obsolete in GCC 4.7.
       Unless there is activity to revive them, the next release of GCC
       will have their sources permanently removed.
       The following ports for individual systems on particular
       architectures have been obsoleted:
          + IRIX 6.5 (mips-sgi-irix6.5)
          + MIPS OpenBSD (mips*-*-openbsd*)
          + Solaris 8 (*-*-solaris2.8). Details can be found in the
            [1]announcement.
          + Tru64 UNIX V5.1 (alpha*-dec-osf5.1*)
     * Support on ARM for the legacy floating-point accelerator (FPA) and
       the mixed-endian floating-point format that it used has been
       obsoleted. The ports that still use this format have been obsoleted
       as well. Many legacy ARM ports already provide an alternative that
       uses the VFP floating-point format. The obsolete ports will be
       deleted in the next release.
       The obsolete ports with alternatives are:
          + arm*-*-rtems (use arm*-*-rtemseabi)
          + arm*-*-linux-gnu (use arm*-*-linux-gnueabi)
          + arm*-*-elf (use arm*-*-eabi)
          + arm*-*-uclinux* (use arm*-*-uclinux*eabi)
       Note, however, that these alternatives are not binary compatible
       with their legacy counterparts (although some can support running
       legacy applications).
       The obsolete ports that currently lack a modern alternative are:
          + arm*-*-ecos-elf
          + arm*-*-freebsd
          + arm*-wince-pe*
       New ports that support more recent versions of the architecture are
       welcome.
     * Support for the Maverick co-processor on ARM has been obsoleted.
       Code to support it will be deleted in the next release.
     * Support has been removed for Unix International threads on Solaris
       2, so the --enable-threads=solaris configure option and the
       -threads compiler option don't work any longer.
     * Support has been removed for the Solaris BSD Compatibility Package,
       which lives in /usr/ucbinclude and /usr/ucblib. It has been removed
       from Solaris 11, and was only intended as a migration aid from
       SunOS 4 to SunOS 5. The -compat-bsd compiler option is not
       recognized any longer.
     * The AVR port's libgcc has been improved and its multilib structure
       has been enhanced. As a result, all objects contributing to an
       application must either be compiled with GCC versions up to 4.6.x
       or with GCC versions 4.7.0 or later.
     * The ARM port's -mwords-little-endian option has been deprecated. It
       will be removed in a future release.
     * Support has been removed for the NetWare x86 configuration
       obsoleted in GCC 4.6.
     * It is no longer possible to use the "l" constraint in MIPS16 asm
       statements.
     * More information on porting to GCC 4.7 from previous versions of
       GCC can be found in the [2]porting guide for this release.

General Optimizer Improvements

     * Support for a new parameter --param case-values-threshold=n was
       added to allow users to control the cutoff between doing switch
       statements as a series of if statements and using a jump table.
     * Link-time optimization (LTO) improvements:
          + Improved scalability and reduced memory usage. Link time
            optimization of Firefox now requires 3GB of RAM on a 64-bit
            system, while over 8GB was needed previously. Linking time has
            been improved, too. The serial stage of linking Firefox has
            been sped up by about a factor of 10.
          + Reduced size of object files and temporary storage used during
            linking.
          + Streaming performance (both outbound and inbound) has been
            improved.
          + ld -r is now supported with LTO.
          + Several bug fixes, especially in symbol table handling and
            merging.
     * Interprocedural optimization improvements:
          + Heuristics now take into account that after inlining code will
            be optimized out because of known values (or properties) of
            function parameters. For example:
void foo(int a)
{
  if (a > 10)
    ... huge code ...
}
void bar (void)
{
  foo (0);
}

            The call of foo will be inlined into bar even when optimizing
            for code size. Constructs based on __builtin_constant_p are
            now understood by the inliner and code size estimates are
            evaluated a lot more realistically.
          + The representation of C++ virtual thunks and aliases (both
            implicit and defined via the alias attribute) has been
            re-engineered. Aliases no longer pose optimization barriers
            and calls to an alias can be inlined and otherwise optimized.
          + The inter-procedural constant propagation pass has been
            rewritten. It now performs generic function specialization.
            For example when compiling the following:
void foo(bool flag)
{
  if (flag)
    ... do something ...
  else
    ... do something else ...
}
void bar (void)
{
  foo (false);
  foo (true);
  foo (false);
  foo (true);
  foo (false);
  foo (true);
}

            GCC will now produce two copies of foo. One with flag being
            true, while other with flag being false. This leads to
            performance improvements previously possible only by inlining
            all calls. Cloning causes a lot less code size growth.
     * A string length optimization pass has been added. It attempts to
       track string lengths and optimize various standard C string
       functions like strlen, strchr, strcpy, strcat, stpcpy and their
       _FORTIFY_SOURCE counterparts into faster alternatives. This pass is
       enabled by default at -O2 or above, unless optimizing for size, and
       can be disabled by the -fno-optimize-strlen option. The pass can
       e.g. optimize
char *bar (const char *a)
{
  size_t l = strlen (a) + 2;
  char *p = malloc (l); if (p == NULL) return p;
  strcpy (p, a); strcat (p, "/"); return p;
}

       into:
char *bar (const char *a)
{
  size_t tmp = strlen (a);
  char *p = malloc (tmp + 2); if (p == NULL) return p;
  memcpy (p, a, tmp); memcpy (p + tmp, "/", 2); return p;
}

       or for hosted compilations where stpcpy is available in the runtime
       and headers provide its prototype, e.g.
void foo (char *a, const char *b, const char *c, const char *d)
{
  strcpy (a, b); strcat (a, c); strcat (a, d);
}

       can be optimized into:
void foo (char *a, const char *b, const char *c, const char *d)
{
  strcpy (stpcpy (stpcpy (a, b), c), d);
}

New Languages and Language specific improvements

     * Version 3.1 of the [3]OpenMP specification is now supported for the
       C, C++, and Fortran compilers.

  Ada

     * The command-line option -feliminate-unused-debug-types has been
       re-enabled by default, as it is for the other languages, leading to
       a reduction in debug info size of 12.5% and more for relevant
       cases, as well as to a small compilation speedup.

  C family

     * A new built-in, __builtin_assume_aligned, has been added, through
       which the compiler can be hinted about pointer alignment and can
       use it to improve generated code.
     * A new -Wunused-local-typedefs warning was added for C, C++,
       Objective-C and Objective-C++. This warning diagnoses typedefs
       locally defined in a function, and otherwise not used.
     * A new experimental -ftrack-macro-expansion option was added for C,
       C++, Objective-C, Objective-C++ and Fortran. It allows the compiler
       to emit diagnostic about the current macro expansion stack when a
       compilation error occurs in a macro expansion.
     * Experimental support for transactional memory has been added. It
       includes support in the compiler, as well as a supporting runtime
       library called libitm. To compile code with transactional memory
       constructs, use the -fgnu-tm option.
       Support is currently available for Alpha, ARM, PowerPC, SH, SPARC,
       and 32-bit/64-bit x86 platforms.
       For more details on transactional memory see [4]the GCC WiKi.
     * Support for atomic operations specifying the C++11/C11 memory model
       has been added. These new __atomic routines replace the existing
       __sync built-in routines.
       Atomic support is also available for memory blocks. Lock-free
       instructions will be used if a memory block is the same size and
       alignment as a supported integer type. Atomic operations which do
       not have lock-free support are left as function calls. A set of
       library functions is available on the GCC atomic wiki in the
       "External Atomics Library" section.
       For more details on the memory models and features, see the
       [5]atomic wiki.
     * When a binary operation is performed on vector types and one of the
       operands is a uniform vector, it is possible to replace the vector
       with the generating element. For example:
typedef int v4si __attribute__ ((vector_size (16)));
v4si res, a = {1,2,3,4};
int x;

res = 2 + a;  /* means {2,2,2,2} + a  */
res = a - x;  /* means a - {x,x,x,x}  */

  C

     * There is support for some more features from the C11 revision of
       the ISO C standard. GCC now accepts the options -std=c11 and
       -std=gnu11, in addition to the previous -std=c1x and -std=gnu1x.
          + Unicode strings (previously supported only with options such
            as -std=gnu11, now supported with -std=c11), and the
            predefined macros __STDC_UTF_16__ and __STDC_UTF_32__.
          + Nonreturning functions (_Noreturn and <stdnoreturn.h>).
          + Alignment support (_Alignas, _Alignof, max_align_t,
            <stdalign.h>).
          + A built-in function __builtin_complex is provided to support C
            library implementation of the CMPLX family of macros.

  C++

     * G++ now accepts the -std=c++11, -std=gnu++11, and -Wc++11-compat
       options, which are equivalent to -std=c++0x, -std=gnu++0x, and
       -Wc++0x-compat, respectively.
     * G++ now implements [6]C++11 extended friend syntax:

template<class W>
class Q
{
  static const int I = 2;
public:
  friend W;
};

struct B
{
  int ar[Q<B>::I];
};

     * Thanks to Ville Voutilainen, G++ now implements [7]C++11 explicit
       override control.

struct B {
  virtual void f() const final;
  virtual void f(int);
};

struct D : B {
  void f() const;            // error: D::f attempts to override final B::f
  void f(long) override;     // error: doesn't override anything
  void f(int) override;      // ok
};

struct E final { };
struct F: E { }; // error: deriving from final class

     * G++ now implements [8]C++11 non-static data member initializers.

struct A {
  int i = 42;
} a; // initializes a.i to 42

     * Thanks to Ed Smith-Rowland, G++ now implements [9]C++11
       user-defined literals.

// Not actually a good approximation.  :)
constexpr long double operator"" _degrees (long double d) { return d * 0.0175; }
long double pi = 180.0_degrees;

     * G++ now implements [10]C++11 alias-declarations.

template <class T> using Ptr = T*;
Ptr<int> ip;  // decltype(ip) is int*

     * Thanks to Ville Voutilainen and Pedro Lamarao, G++ now implements
       [11]C++11 delegating constructors.

struct A {
  A(int);
  A(): A(42) { } // delegate to the A(int) constructor
};

     * G++ now fully implements C++11 atomic classes rather than just
       integer derived classes.

class POD {
  int a;
  int b;
};
std::atomic<POD> my_atomic_POD;

     * G++ now sets the predefined macro __cplusplus to the correct value,
       199711L for C++98/03, and 201103L for C++11.
     * G++ now correctly implements the two-phase lookup rules such that
       an unqualified name used in a template must have an appropriate
       declaration found either in scope at the point of definition of the
       template or by argument-dependent lookup at the point of
       instantiation. As a result, code that relies on a second
       unqualified lookup at the point of instantiation to find functions
       declared after the template or in dependent bases will be rejected.
       The compiler will suggest ways to fix affected code, and using the
       -fpermissive compiler flag will allow the code to compile with a
       warning.

template <class T>
void f() { g(T()); } // error, g(int) not found by argument-dependent lookup
void g(int) { } // fix by moving this declaration before the declaration of f

template <class T>
struct A: T {
  // error, B::g(B) not found by argument-dependent lookup
  void f() { g(T()); } // fix by using this->g or A::g
};

struct B { void g(B); };

int main()
{
  f<int>();
  A<B>().f();
}

     * G++ now properly re-uses stack space allocated for temporary
       objects when their lifetime ends, which can significantly lower
       stack consumption for some C++ functions. As a result of this, some
       code with undefined behavior will now break:

const int &f(const int &i) { return i; }
....
const int &x = f(1);
const int &y = f(2);

       Here, x refers to the temporary allocated to hold the 1 argument,
       which only lives until the end of the initialization; it
       immediately becomes a dangling reference. So the next statement
       re-uses the stack slot to hold the 2 argument, and users of x get
       that value instead.
       Note that this should not cause any change of behavior for
       temporaries of types with non-trivial destructors, as they are
       already destroyed at end of full-expression; the change is that now
       the storage is released as well.
     * A new command-line option -Wdelete-non-virtual-dtor has been added
       to warn when delete is used to destroy an instance of a class which
       has virtual functions and non-virtual destructor. It is unsafe to
       delete an instance of a derived class through a pointer to a base
       class if the base class does not have a virtual destructor. This
       warning is enabled by -Wall.
     * A new command-line option -Wzero-as-null-pointer-constant has been
       added to warn when a literal '0' is used as null pointer constant.
       It can be useful to facilitate the conversion to nullptr in C++11.
     * As per C++98, access-declarations are now deprecated by G++.
       Using-declarations are to be used instead. Furthermore, some
       efforts have been made to improve the support of class scope
       using-declarations. In particular, using-declarations referring to
       a dependent type now work as expected ([12]bug c++/14258).
     * The ELF symbol visibility of a template instantiation is now
       properly constrained by the visibility of its template arguments
       ([13]bug c++/35688).

    Runtime Library (libstdc++)

     * [14]Improved experimental support for the new ISO C++ standard,
       C++11, including:
          + using noexcept in most of the library;
          + implementations of pointer_traits, allocator_traits and
            scoped_allocator_adaptor;
          + uses-allocator construction for tuple;
          + vector meets the allocator-aware container requirements;
          + replacing monotonic_clock with steady_clock;
          + enabling the thread support library on most POSIX targets;
          + many small improvements to conform to the FDIS.
     * Added --enable-clocale=newlib configure option.
     * Debug Mode iterators for unordered associative containers.
     * Avoid polluting the global namespace and do not include <unistd.h>.

  Fortran

     * The compile flag [15]-fstack-arrays has been added, which causes
       all local arrays to be put on stack memory. For some programs this
       will improve the performance significantly. If your program uses
       very large local arrays, it is possible that you will have to
       extend your runtime limits for stack memory.
     * The [16]-Ofast flag now also implies [17]-fno-protect-parens and
       [18]-fstack-arrays.
     * Front-end optimizations can now be selected by the
       [19]-ffrontend-optimize option and deselected by the
       -fno-frontend-optimize option.
     * When front-end optimization removes a function call,
       [20]-Wfunction-elimination warns about that.
     * When performing front-end-optimization, the
       [21]-faggressive-function-elimination option allows the removal of
       duplicate function calls even for impure functions.
     * The flag [22]-Wreal-q-constant has been added, which warns if
       floating-point literals have been specified using q (such as
       1.0q0); the q marker is now supported as a vendor extension to
       denote quad precision (REAL(16) or, if not available, REAL(10)).
       Consider using a kind parameter (such as in 1.0_qp) instead, which
       can be obtained via [23]SELECTED_REAL_KIND.
     * The GFORTRAN_USE_STDERR environment variable has been removed. GNU
       Fortran now always prints error messages to standard error. If you
       wish to redirect standard error, please consult the manual for your
       OS, shell, batch environment etc. as appropriate.
     * The -fdump-core option and GFORTRAN_ERROR_DUMPCORE environment
       variable have been removed. When encountering a serious error,
       gfortran will now always abort the program. Whether a core dump is
       generated depends on the user environment settings; see the ulimit
       -c setting for POSIX shells, limit coredumpsize for C shells, and
       the [24]WER user-mode dumps settings on Windows.
     * The [25]-fbacktrace option is now enabled by default. When
       encountering a fatal error, gfortran will attempt to print a
       backtrace to standard error before aborting. It can be disabled
       with -fno-backtrace. Note: On POSIX targets with the addr2line
       utility from GNU binutils, GNU Fortran can print a backtrace with
       function name, file name, line number information in addition to
       the addresses; otherwise only the addresses are printed.
     * [26]Fortran 2003:
          + Generic interface names which have the same name as derived
            types are now supported, which allows to write constructor
            functions. Note that Fortran does not support static
            constructor functions; only default initialization or an
            explicit structure-constructor initialization are available.
          + [27]Polymorphic (class) arrays are now supported.
     * [28]Fortran 2008:
          + Support for the DO CONCURRENT construct has been added, which
            allows the user to specify that individual loop iterations
            have no interdependencies.
          + [29]Coarrays: Full single-image support except for polymorphic
            coarrays. Additionally, preliminary support for multiple
            images via an MPI-based [30]coarray communication library has
            been added. Note: The library version is not yet usable as
            remote coarray access is not yet possible.
     * [31]TS 29113:
          + New flag [32]-std=f2008ts permits programs that are expected
            to conform to the Fortran 2008 standard and the draft
            Technical Specification (TS) 29113 on Further Interoperability
            of Fortran with C.
          + The OPTIONAL attribute is now allowed for dummy arguments of
            BIND(C) procedures.
          + The RANK intrinsic has been added.
          + The implementation of the ASYNCHRONOUS attribute in GCC is
            compatible with the candidate draft of TS 29113 (since GCC
            4.6).

  Go

     * GCC 4.7 implements the [33]Go 1 language standard. The library
       support in 4.7.0 is not quite complete, due to release timing.
       Release 4.7.1 is expected to include complete support.
     * Go has been tested on GNU/Linux and Solaris platforms. It may work
       on other platforms as well.

New Targets and Target Specific Improvements

  ARM

     * GCC now supports the Cortex-A7 processor implementing the v7-a
       version of the architecture using the option -mcpu=cortex-a7.
     * The default vector size in auto-vectorization for NEON is now 128
       bits. If vectorization fails thusly, the vectorizer tries again
       with 64-bit vectors.
     * A new option -mvectorize-with-neon-double was added to allow users
       to change the vector size to 64 bits.

  AVR

     * GCC now supports the XMEGA architecture. This requires GNU binutils
       2.22 or later.
     * Support for the [34]named address spaces __flash, __flash1, ...,
       __flash5 and __memx has been added. These address spaces locate
       read-only data in flash memory and allow reading from flash memory
       by means of ordinary C code, i.e. without the need of (inline)
       assembler code:

const __flash int values[] = { 42, 31 };

int add_values (const __flash int *p, int i)
{
    return values[i] + *p;
}

     * Support for AVR-specific [35]built-in functions has been added.
     * Support has been added for the signed and unsigned 24-bit scalar
       integer types __int24 and __uint24.
     * New command-line options -maccumulate-args, -mbranch-cost=cost and
       -mstrict-X were added to allow better fine-tuning of code
       optimization.
     * The command option -fdata-sections now also takes affect on the
       section names of variables with the progmem attribute.
     * A new inline assembler print modifier %i to print a RAM address as
       I/O address has been added:

#include <avr/io.h> /* Port Definitions from AVR-LibC */

void set_portb (uint8_t value)
{
    asm volatile ("out %0, %i1" :: "r" (value), "n" (&PORTB) : "memory");
}

       The offset between an I/O address and the RAM address for that I/O
       location is device-specific. This offset is taken into account when
       printing a RAM address with the %i modifier so that the address is
       suitable to be used as operand in an I/O command. The address must
       be a constant integer known at compile time.
     * The inline assembler constraint "R" to represent integers in the
       range -6 ... 5 has been removed without replacement.
     * Many optimizations to:
          + 64-bit integer arithmetic
          + Widening multiplication
          + Integer division by a constant
          + Avoid constant reloading in multi-byte instructions.
          + Micro-optimizations for special instruction sequences.
          + Generic built-in functions like __builtin_ffs*,
            __builtin_clz*, etc.
          + If-else decision trees generated by switch instructions
          + Merging of data located in flash memory
          + New libgcc variants for devices with 8-bit wide stack pointer
          + ...
     * Better documentation:
          + Handling of EIND and indirect jumps on devices with more than
            128 KiB of program memory.
          + Handling of the RAMPD, RAMPX, RAMPY and RAMPZ special function
            registers.
          + Function attributes OS_main and OS_task.
          + AVR-specific built-in macros.

  C6X

     * Support has been added for the Texas Instruments C6X family of
       processors.

  CR16

     * Support has been added for National Semiconductor's CR16
       architecture.

  Epiphany

     * Support has been added for Adapteva's Epiphany architecture.

  IA-32/x86-64

     * Support for Intel AVX2 intrinsics, built-in functions and code
       generation is available via -mavx2.
     * Support for Intel BMI2 intrinsics, built-in functions and code
       generation is available via -mbmi2.
     * Implementation and automatic generation of __builtin_clz* using the
       lzcnt instruction is available via -mlzcnt.
     * Support for Intel FMA3 intrinsics and code generation is available
       via -mfma.
     * A new -mfsgsbase command-line option is available that makes GCC
       generate new segment register read/write instructions through
       dedicated built-ins.
     * Support for the new Intel rdrnd instruction is available via
       -mrdrnd.
     * Two additional AVX vector conversion instructions are available via
       -mf16c.
     * Support for new Intel processor codename IvyBridge with RDRND,
       FSGSBASE and F16C is available through -march=core-avx-i.
     * Support for the new Intel processor codename Haswell with AVX2,
       FMA, BMI, BMI2, LZCNT is available through -march=core-avx2.
     * Support for new AMD family 15h processors (Piledriver core) is now
       available through -march=bdver2 and -mtune=bdver2 options.
     * Support for [36]the x32 psABI is now available through the -mx32
       option.
     * Windows mingw targets are using the -mms-bitfields option by
       default.
     * Windows x86 targets are using the __thiscall calling convention for
       C++ class-member functions.
     * Support for the configure option --with-threads=posix for Windows
       mingw targets.

  MIPS

     * GCC now supports thread-local storage (TLS) for MIPS16. This
       requires GNU binutils 2.22 or later.
     * GCC can now generate code specifically for the Cavium Octeon+ and
       Octeon2 processors. The associated command-line options are
       -march=octeon+ and -march=octeon2 respectively. Both options
       require GNU binutils 2.22 or later.
     * GCC can now work around certain 24k errata, under the control of
       the command-line option -mfix-24k. These workarounds require GNU
       binutils 2.20 or later.
     * 32-bit MIPS GNU/Linux targets such as mips-linux-gnu can now build
       n32 and n64 multilibs. The result is effectively a 64-bit GNU/Linux
       toolchain that generates 32-bit code by default. Use the
       configure-time option --enable-targets=all to select these extra
       multilibs.
     * Passing -fno-delayed-branch now also stops the assembler from
       automatically filling delay slots.

  PowerPC/PowerPC64

     * Vectors of type vector long long or vector long are passed and
       returned using the same method as other vectors with the VSX
       instruction set. Previously GCC did not adhere to the ABI for
       128-bit vectors with 64-bit integer base types (PR 48857). This
       will also be fixed in the GCC 4.6.1 and 4.5.4 releases.
     * A new option -mno-pointers-to-nested-functions was added to allow
       AIX 32-bit/64-bit and GNU/Linux 64-bit PowerPC users to specify
       that the compiler should not load up the chain register (r11)
       before calling a function through a pointer. If you use this
       option, you cannot call nested functions through a pointer, or call
       other languages that might use the static chain.
     * A new option msave-toc-indirect was added to allow AIX
       32-bit/64-bit and GNU/Linux 64-bit PowerPC users control whether we
       save the TOC in the prologue for indirect calls or generate the
       save inline. This can speed up some programs that call through a
       function pointer a lot, but it can slow down other functions that
       only call through a function pointer in exceptional cases.
     * The PowerPC port will now enable machine-specific built-in
       functions when the user switches the target machine using the
       #pragma GCC target or __attribute__ ((__target__ ("target"))) code
       sequences. In additon, the target macros are updated. However, due
       to the way the -save-temps switch is implemented, you won't see the
       effect of these additional macros being defined in preprocessor
       output.

  SH

     * A new option -msoft-atomic has been added. When it is specified,
       GCC will generate GNU/Linux-compatible gUSA atomic sequences for
       the new __atomic routines.
     * Since it is neither supported by GAS nor officially documented,
       code generation for little endian SH2A has been disabled.
       Specifying -ml with -m2a* will now result in a compiler error.
     * The defunct -mbranch-cost option has been fixed.
     * Some improvements to the generated code of:
          + Utilization of the tst #imm,R0 instruction.
          + Dynamic shift instructions on SH2A.
          + Integer absolute value calculations.

  SPARC

     * The option -mflat has been reinstated. When it is specified, the
       compiler will generate code for a single register window model.
       This is essentially a new implementation and the corresponding
       debugger support has been added to GDB 7.4.
     * Support for the options -mtune=native and -mcpu=native has been
       added on selected native platforms (GNU/Linux and Solaris).
     * Support for the SPARC T3 (Niagara 3) processor has been added.
     * VIS:
          + An intrinsics header visintrin.h has been added.
          + Builtin intrinsics for the VIS 1.0 edge handling and pixel
            compare instructions have been added.
          + The little-endian version of alignaddr is now supported.
          + When possible, VIS builtins are marked const, which should
            increase the compiler's ability to optimize VIS operations.
          + The compiler now properly tracks the %gsr register and how it
            behaves as an input for various VIS instructions.
          + Akin to fzero, the compiler can now generate fone instructions
            in order to set all of the bits of a floating-point register
            to 1.
          + The documentation for the VIS intrinsics in the GCC manual has
            been brought up to date and many inaccuracies were fixed.
          + Intrinsics for the VIS 2.0 bmask, bshuffle, and
            non-condition-code setting edge instructions have been added.
            Their availability is controlled by the new -mvis2 and
            -mno-vis2 options. They are enabled by default on
            UltraSPARC-III and later CPUs.
     * Support for UltraSPARC Fused Multiply-Add floating-point extensions
       has been added. These instructions are enabled by default on SPARC
       T3 (Niagara 3) and later CPUs.

  TILE-Gx/TILEPro

     * Support has been added for the Tilera TILE-Gx and TILEPro families
       of processors.

Other significant improvements

     * A new option (-grecord-gcc-switches) was added that appends
       compiler command-line options that might affect code generation to
       the DW_AT_producer attribute string in the DWARF debugging
       information.
     * GCC now supports various new GNU extensions to the DWARF debugging
       information format, like [37]entry value and [38]call site
       information, [39]typed DWARF stack or [40]a more compact macro
       representation. Support for these extensions has been added to GDB
       7.4. They can be disabled through the -gstrict-dwarf command-line
       option.

GCC 4.7.1

   This is the [41]list of problem reports (PRs) from GCC's bug tracking
   system that are known to be fixed in the 4.7.1 release. This list might
   not be complete (that is, it is possible that some PRs that have been
   fixed are not listed here).


    For questions related to the use of GCC, please consult these web
    pages and the [42]GCC manuals. If that fails, the
    [43]gcc-help@gcc.gnu.org mailing list might help. Comments on these
    web pages and the development of GCC are welcome on our developer
    list at [44]gcc@gcc.gnu.org. All of [45]our lists have public
    archives.

   Copyright (C) [46]Free Software Foundation, Inc. Verbatim copying and
   distribution of this entire article is permitted in any medium,
   provided this notice is preserved.

   These pages are [47]maintained by the GCC team. Last modified
   2012-06-14[48].

References

   1. http://gcc.gnu.org/ml/gcc-patches/2011-03/msg01263.html
   2. http://gcc.gnu.org/gcc-4.7/porting_to.html
   3. http://openmp.org/wp/openmp-specifications/
   4. http://gcc.gnu.org/wiki/TransactionalMemory
   5. http://gcc.gnu.org/wiki/Atomic/GCCMM
   6. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   7. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   8. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
   9. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
  10. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
  11. http://gcc.gnu.org/gcc-4.7/cxx0x_status.html
  12. http://gcc.gnu.org/PR14258
  13. http://gcc.gnu.org/PR35688
  14. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/libstdc++/manual/manual/status.html#status.iso.2011
  15. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254
  16. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Optimize-Options.html#index-Ofast-689
  17. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfno-protect-parens_007d-270
  18. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfstack-arrays_007d-254
  19. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfrontend-optimize_007d-275
  20. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWfunction-elimination_007d-170
  21. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Code-Gen-Options.html#index-g_t_0040code_007bfaggressive-function-elimination_007d-270
  22. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Error-and-Warning-Options.html#index-g_t_0040code_007bWreal-q-constant_007d-149
  23. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/SELECTED_005fREAL_005fKIND.html
  24. http://msdn.microsoft.com/en-us/library/bb787181%28v=vs.85%29.aspx
  25. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Debugging-Options.html#index-g_t_0040code_007bfno-backtrace_007d-183
  26. http://gcc.gnu.org/wiki/Fortran2003Status
  27. http://gcc.gnu.org/wiki/OOP
  28. http://gcc.gnu.org/wiki/Fortran2008Status
  29. http://gcc.gnu.org/wiki/Coarray
  30. http://gcc.gnu.org/wiki/CoarrayLib
  31. http://gcc.gnu.org/wiki/TS29113Status
  32. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gfortran/Fortran-Dialect-Options.html#index-g_t_0040code_007bstd_003d_007d_0040var_007bstd_007d-option-53
  33. http://weekly.golang.org/doc/go1.html
  34. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Named-Address-Spaces.html
  35. http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/AVR-Built%5f002din-Functions.html
  36. http://sites.google.com/site/x32abi/
  37. http://www.dwarfstd.org/ShowIssue.php?issue=100909.1
  38. http://www.dwarfstd.org/ShowIssue.php?issue=100909.2
  39. http://www.dwarfstd.org/doc/040408.1.html
  40. http://www.dwarfstd.org/ShowIssue.php?issue=110722.1
  41. http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.7.1
  42. http://gcc.gnu.org/onlinedocs/
  43. mailto:gcc-help@gcc.gnu.org
  44. mailto:gcc@gcc.gnu.org
  45. http://gcc.gnu.org/lists.html
  46. http://www.fsf.org/
  47. http://gcc.gnu.org/about.html
  48. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.6/index.html

                             GCC 4.6 Release Series

   March 1, 2012

   The [1]GNU project and the GCC developers are pleased to announce the
   release of GCC 4.6.3.

   This release is a bug-fix release, containing fixes for regressions in
   GCC 4.6.2 relative to previous releases of GCC.

Release History

   GCC 4.6.3
          March 1, 2012 ([2]changes)

   GCC 4.6.2
          October 26, 2011 ([3]changes)

   GCC 4.6.1
          June 27, 2011 ([4]changes)

   GCC 4.6.0
          March 25, 2011 ([5]changes)

References and Acknowledgements

   GCC used to stand for the GNU C Compiler, but since the compiler
   supports several other languages aside from C, it now stands for the
   GNU Compiler Collection.

   A list of [6]successful builds is updated as new information becomes
   available.

   The GCC developers would like to thank the numerous people that have
   contributed new features, improvements, bug fixes, and other changes as
   well as test results to GCC. This [7]amazing group of volunteers is
   what makes GCC successful.

   For additional information about GCC please refer to the [8]GCC project
   web site or contact the [9]GCC development mailing list.

   To obtain GCC please use [10]our mirror sites or [11]our SVN server.


    For questions related to the use of GCC, please consult these web
    pages and the [12]GCC manuals. If that fails, the
    [13]gcc-help@gcc.gnu.org mailing list might help. Comments on these
    web pages and the development of GCC are welcome on our developer
    list at [14]gcc@gcc.gnu.org. All of [15]our lists have public
    archives.

   Copyright (C) [16]Free Software Foundation, Inc. Verbatim copying and
   distribution of this entire article is permitted in any medium,
   provided this notice is preserved.

   These pages are [17]maintained by the GCC team. Last modified
   2012-03-01[18].

References

   1. http://www.gnu.org/
   2. http://gcc.gnu.org/gcc-4.6/changes.html
   3. http://gcc.gnu.org/gcc-4.6/changes.html
   4. http://gcc.gnu.org/gcc-4.6/changes.html
   5. http://gcc.gnu.org/gcc-4.6/changes.html
   6. http://gcc.gnu.org/gcc-4.6/buildstat.html
   7. http://gcc.gnu.org/onlinedocs/gcc/Contributors.html
   8. http://gcc.gnu.org/index.html
   9. mailto:gcc@gcc.gnu.org
  10. http://gcc.gnu.org/mirrors.html
  11. http://gcc.gnu.org/svn.html
  12. http://gcc.gnu.org/onlinedocs/
  13. mailto:gcc-help@gcc.gnu.org
  14. mailto:gcc@gcc.gnu.org
  15. http://gcc.gnu.org/lists.html
  16. http://www.fsf.org/
  17. http://gcc.gnu.org/about.html
  18. http://validator.w3.org/check/referer
======================================================================
http://gcc.gnu.org/gcc-4.6/changes.html

                             GCC 4.6 Release Series
                        Changes, New Features, and Fixes

Caveats

     * The options -b <machine> and -V <version> have been removed because
       they were unreliable. Instead, users should directly run
       <machine>-gcc when cross-compiling, or <machine>-gcc-<version> to
       run a different version of gcc.
     * GCC now has stricter checks for invalid command-line options. In
       particular, when gcc was called to link object files rather than
       compile source code, it would previously accept and ignore all
       options starting with --, including linker options such as
       --as-needed and --export-dynamic, although such options would
       result in errors if any source code was compiled. Such options, if
       unknown to the compiler, are now rejected in all cases; if the
       intent was to pass them to the linker, options such as
       -Wl,--as-needed should be used.
     * Versions of the GNU C library up to and including 2.11.1 included
       an [1]incorrect implementation of the cproj function. GCC optimizes
       its builtin cproj according to the behavior specified and allowed
       by the ISO C99 standard. If you want to avoid discrepancies between
       the C library and GCC's builtin transformations when using cproj in
       your code, use GLIBC 2.12 or later. If you are using an older GLIBC
       and actually rely on the incorrect behavior of cproj, then you can
       disable GCC's transformations using -fno-builtin-cproj.
     * The C-only intermodule optimization framework (IMA, enabled by
       -combine) has been removed in favor of the new generic link-time
       optimization framework (LTO) introduced in [2]GCC 4.5.0.
     * GCC now ships with the LGPL-licensed libquadmath library, which
       provides quad-precision mathematical functions for targets with a
       __float128 datatype. __float128 is available for targets on 32-bit
       x86, x86-64 and Itanium architectures. The libquadmath library is
       automatically built on such targets when building the Fortran
       compiler.
     * New -Wunused-but-set-variable and -Wunused-but-set-parameter
       warnings were added for C, C++, Objective-C and Objective-C++.
       These warnings diagnose variables respective parameters which are
       only set in the code and never otherwise used. Usually such
       variables are useless and often even the value assigned to them is
       computed needlessly, sometimes expensively. The
       -Wunused-but-set-variable warning is enabled by default by -Wall
       flag and -Wunused-but-set-parameter by -Wall -Wextra flags.
     * Support for a number of older systems and recently unmaintained or
       untested target ports of GCC has been declared obsolete in GCC 4.6.
       Unless there is activity to revive them, the next release of GCC
       will have their sources permanently removed.
       All GCC ports for the following processor architectures have been
       declared obsolete:
          + Argonaut ARC (arc-*)
          + National Semiconductor CRX (crx-*)
          + Motorola 68HC11 and 68HC12 (m68hc11-*-*, m6811-*-*,
            m68hc12-*-*, m6812-*-*)
          + Sunplus S+core (score-*)
       The following ports for individual systems on particular
       architectures have been obsoleted:
          + Interix (i[34567]86-*-interix3*)
          + NetWare x86 (i[3456x]86-*-netware*)
          + Generic ARM PE (arm-*-pe* other than arm*-wince-pe*)
          + MCore PE (mcore-*-pe*)
          + SH SymbianOS (sh*-*-symbianelf*)
          + GNU Hurd on Alpha and PowerPC (alpha*-*-gnu*, powerpc*-*-gnu*)
          + M68K uClinux old ABI (m68k-*-uclinuxoldabi*)
          + a.out NetBSD (arm*-*-netbsd*, i[34567]86-*-netbsd*,
            vax-*-netbsd*, but not *-*-netbsdelf*)
       The i[34567]86-*-pe alias for Cygwin targets has also been
       obsoleted; users should configure for i[34567]86-*-cygwin* instead.
       Certain configure options to control the set of libraries built
       with GCC on some targets have been obsoleted. On ARM targets, the
       options --disable-fpu, --disable-26bit, --disable-underscore,
