GNU Compiler Collection 4.7.0 - Changelog

What's new in GNU Compiler Collection 4.7.0:

· Regression fixes and docs only.

What's new in GNU Compiler Collection 4.6.2:

· This release is a bug-fix release, containing fixes for regressions in GCC 4.6.1 relative to previous releases of GCC.

What's new in GNU Compiler Collection 4.6.1:

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*)
· 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*)

What's new in GNU Compiler Collection 4.6.0:

· 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 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 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.

What's new in GNU Compiler Collection 4.5.2:

· GCC now requires the MPC library in order to build. See the prerequisites page for version requirements.
· Support has been removed for all the configurations obsoleted in GCC 4.4.
· Support has been removed for the protoize and unprotoize utilities, obsoleted in GCC 4.4.
· Support has been removed for tuning for Itanium1 (Merced) variants. Note that code tuned for Itanium2 should also run correctly on Itanium1.
· Documentation improvements.

What's new in GNU Compiler Collection 4.4.2:

· On ARM EABI targets, the C++ mangling of the va_list type has been changed to conform to the current revision of the EABI. This does not affect the libstdc++ library included with GCC.
· The SCOUNT and POS bits of the MIPS DSP control register are now treated as global. Previous versions of GCC treated these fields as call-clobbered instead.
· The MIPS port no longer recognizes the h asm constraint. It was necessary to remove this constraint in order to avoid generating unpredictable code sequences.
· __builtin_stdarg_start has been completely removed from GCC. Support for <varargs.h> had been deprecated since GCC 4.0. Use __builtin_va_start as a replacement.
· Some of the errors issued by the C++ front end that could be downgraded to warnings in previous releases by using -fpermissive are now warnings by default. They can be converted into errors by using -pedantic-errors.
· Use of the cpp assertion extension will now emit a warning when -Wdeprecated or -pedantic is used. This extension has been deprecated for many years, but never warned about.

What's new in GNU Compiler Collection 4.4.1:

· A new command-line switch -findirect-inlining has been added. When turned on it allows the inliner to also inline indirect calls that are discovered to have known targets at compile time thanks to previous inlining.
· A new command-line switch -ftree-switch-conversion has been added. This new pass turns simple initializations of scalar variables in switch statements into initializations from a static array, given that all the values are known at compile time and the ratio between the new array size and the original switch branches does not exceed the parameter --param switch-conversion-max-branch-ratio (default is eight).
· A new command-line switch -ftree-builtin-call-dce has been added. This optimization eliminates unnecessary calls to certain builtin functions when the return value is not used, in cases where the calls can not be eliminated entirely because the function may set errno. This optimization is on by default at -O2 and above.
· A new command-line switch -fconserve-stack directs the compiler to minimize stack usage even if it makes the generated code slower. This affects inlining decisions.
· When the assembler supports it, the compiler will now emit unwind information using assembler .cfi directives. This makes it possible to use such directives in inline assembler code. The new option -fno-dwarf2-cfi-asm directs the compiler to not use .cfi directives.