initial import of GCC 12.3.0.

major changes in GCC 11 included:

- The default mode for C++ is now -std=gnu++17 instead of -std=gnu++14.
- When building GCC itself, the host compiler must now suppor

initial import of GCC 12.3.0.

major changes in GCC 11 included:

- The default mode for C++ is now -std=gnu++17 instead of -std=gnu++14.
- When building GCC itself, the host compiler must now support C++11,
rather than C++98.
- Some short options of the gcov tool have been renamed: -i to -j and
-j to -H.
- ThreadSanitizer improvements.
- Introduce Hardware-assisted AddressSanitizer support.
- For targets that produce DWARF debugging information GCC now defaults
to DWARF version 5. This can produce up to 25% more compact debug
information compared to earlier versions.
- Many optimisations.
- The existing malloc attribute has been extended so that it can be
used to identify allocator/deallocator API pairs. A pair of new
-Wmismatched-dealloc and -Wmismatched-new-delete warnings are added.
- Other new warnings:
-Wsizeof-array-div, enabled by -Wall, warns about divisions of two
sizeof operators when the first one is applied to an array and the
divisor does not equal the size of the array element.
-Wstringop-overread, enabled by default, warns about calls to string
functions reading past the end of the arrays passed to them as
arguments.
-Wtsan, enabled by default, warns about unsupported features in
ThreadSanitizer (currently std::atomic_thread_fence).
- Enchanced warnings:
-Wfree-nonheap-object detects many more instances of calls to
deallocation functions with pointers not returned from a dynamic
memory allocation function.
-Wmaybe-uninitialized diagnoses passing pointers or references to
uninitialized memory to functions taking const-qualified arguments.
-Wuninitialized detects reads from uninitialized dynamically
allocated memory.
-Warray-parameter warns about functions with inconsistent array forms.
-Wvla-parameter warns about functions with inconsistent VLA forms.
- Several new features from the upcoming C2X revision of the ISO C
standard are supported with -std=c2x and -std=gnu2x.
- Several C++20 features have been implemented.
- The C++ front end has experimental support for some of the upcoming
C++23 draft.
- Several new C++ warnings.
- Enhanced Arm, AArch64, x86, and RISC-V CPU support.
- The implementation of how program state is tracked within
-fanalyzer has been completely rewritten with many enhancements.

see https://gcc.gnu.org/gcc-11/changes.html for a full list.

major changes in GCC 12 include:

- An ABI incompatibility between C and C++ when passing or returning
by value certain aggregates containing zero width bit-fields has
been discovered on various targets. x86-64, ARM and AArch64
will always ignore them (so there is a C ABI incompatibility
between GCC 11 and earlier with GCC 12 or later), PowerPC64 ELFv2
always take them into account (so there is a C++ ABI
incompatibility, GCC 4.4 and earlier compatible with GCC 12 or
later, incompatible with GCC 4.5 through GCC 11). RISC-V has
changed the handling of these already starting with GCC 10. As
the ABI requires, MIPS takes them into account handling function
return values so there is a C++ ABI incompatibility with GCC 4.5
through 11.
- STABS: Support for emitting the STABS debugging format is
deprecated and will be removed in the next release. All ports now
default to emit DWARF (version 2 or later) debugging info or are
obsoleted.
- Vectorization is enabled at -O2 which is now equivalent to the
original -O2 -ftree-vectorize -fvect-cost-model=very-cheap.
- GCC now supports the ShadowCallStack sanitizer.
- Support for __builtin_shufflevector compatible with the clang
language extension was added.
- Support for attribute unavailable was added.
- Support for __builtin_dynamic_object_size compatible with the
clang language extension was added.
- New warnings:
-Wbidi-chars warns about potentially misleading UTF-8
bidirectional control characters.
-Warray-compare warns about comparisons between two operands of
array type.
- Some new features from the upcoming C2X revision of the ISO C
standard are supported with -std=c2x and -std=gnu2x.
- Several C++23 features have been implemented.
- Many C++ enhancements across warnings and -f options.

see https://gcc.gnu.org/gcc-12/changes.html for a full list.

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initial import of GCC 10.3.0. main changes include:

caveats:
- ABI issue between c++14 and c++17 fixed
- profile mode is removed from libstdc++
- -fno-common is now the default

new features:
- new

initial import of GCC 10.3.0. main changes include:

caveats:
- ABI issue between c++14 and c++17 fixed
- profile mode is removed from libstdc++
- -fno-common is now the default

new features:
- new flags -fallocation-dce, -fprofile-partial-training,
-fprofile-reproducible, -fprofile-prefix-path, and -fanalyzer
- many new compile and link time optimisations
- enhanced drive optimisations
- openacc 2.6 support
- openmp 5.0 features
- new warnings: -Wstring-compare and -Wzero-length-bounds
- extended warnings: -Warray-bounds, -Wformat-overflow,
-Wrestrict, -Wreturn-local-addr, -Wstringop-overflow,
-Warith-conversion, -Wmismatched-tags, and -Wredundant-tags
- some likely C2X features implemented
- more C++20 implemented
- many new arm & intel CPUs known

hundreds of reported bugs are fixed. full list of changes
can be found at:

https://gcc.gnu.org/gcc-10/changes.html

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initial import of GCC 9.3.0. changes include:

- live patching support
- shell completion help
- generally better diagnostic output (less verbose/more useful)
- diagnostics and optimisation choices

initial import of GCC 9.3.0. changes include:

- live patching support
- shell completion help
- generally better diagnostic output (less verbose/more useful)
- diagnostics and optimisation choices can be emitted in json
- asan memory usage reduction
- many general, and specific to switch, inter-procedure,
profile and link-time optimisations. from the release notes:
"Overall compile time of Firefox 66 and LibreOffice 6.2.3 on
an 8-core machine was reduced by about 5% compared to GCC 8.3"
- OpenMP 5.0 support
- better spell-guesser
- partial experimental support for c2x and c++2a
- c++17 is no longer experimental
- arm AAPCS GCC 6-8 structure passing bug fixed, may cause
incompatibility (restored compat with GCC 5 and earlier.)
- openrisc support

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re-import GCC 8.4.0.

import GCC 7.5.0. doing this here so that the vendor branch has
the code we'll merge into gcc.old and the netbsd-9 tree gcc tree.
GCC 8.4.0 will be imported immediately on top of this again,
restori

import GCC 7.5.0. doing this here so that the vendor branch has
the code we'll merge into gcc.old and the netbsd-9 tree gcc tree.
GCC 8.4.0 will be imported immediately on top of this again,
restoring the current status.

these PRs in the GCC bugzilla are fixed with this update:

89869 80693 89795 84272 85593 86669 87148 87647 87895 88103 88107 88563
88870 88976 89002 89187 89195 89234 89303 89314 89354 89361 89403 89412
89512 89520 89590 89621 89663 89679 89704 89734 89872 89933 90090 90208
87075 85870 89009 89242 88167 80864 81933 85890 86608 87145 88857 89024
89119 89214 89511 89612 89705 89400 81740 82186 84552 86554 87609 88105
88149 88415 88739 88903 89135 89223 89296 89505 89572 89677 89698 89710
90006 90020 90071 90328 90474 91126 91162 91812 91887 90075 88998 89945
87047 87506 88074 88656 88740 91137 89008 84010 89349 91136 91347 91995
89397 87030 60702 78884 85594 87649 87725 88181 88470 88553 88568 88588
88620 88644 88906 88949 89246 89587 89726 89768 89796 89998 90108 90756
90950 91704 88825 88983 86538 51333 89446 90220 91308 92143 89392 90213
90278 91131 91200 91510 89037 91481 87673 88418 88938 88948 90547 27221
58321 61250 67183 67958 77583 83531 86215 88648 88720 88726 89091 89466
89629 90105 90329 90585 90760 90924 91087 89222 81956 71861 35031 69455
81849 82993 85798 88138 88155 88169 88205 88206 88228 88249 88269 88376
77703 80260 82077 86248 88393 90786 57048 66089 66695 67679 68009 71723
72714 84394 85544 87734 88298 90937 91557 63891 64132 65342 68649 68717
71066 71860 71935 77746 78421 78645 78865 78983 79485 79540 85953 88326
89651 90744

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import GCC 8.3. it includes these new features:
- many optimisations improved: inter-procedural, profile-directed,
LTO, loops including user-controllable unroll support, and more.
- columns number

import GCC 8.3. it includes these new features:
- many optimisations improved: inter-procedural, profile-directed,
LTO, loops including user-controllable unroll support, and more.
- columns numbers added to line numbers in dwarf
- gcov extended significantly
- many sanitizer updates
- many new warning messages
- many better hints and more useful error messages
- minor ABI changes on x86-64 libstdc++, and some c++17 modes
- draft c++2a features
- better c++17 experimental support
- Armv8.4-A supported, better 8.2-A and 8.3-A support, including
32 bit arm port. cortex a-55, a-75 and a-55.a-75 combo support.
- in the GCC bugzilla, 8.1 shows 1149 bugs fixed, 8.2 shows 100, and
8.3 shows 158.

show more ...

import GCC 7.4.0. main changes include:

The non-standard C++0x type traits has_trivial_default_constructor,
has_trivial_copy_constructor and has_trivial_copy_assign have been
removed.

On ARM targe

import GCC 7.4.0. main changes include:

The non-standard C++0x type traits has_trivial_default_constructor,
has_trivial_copy_constructor and has_trivial_copy_assign have been
removed.

On ARM targets (arm*-*-*), a bug introduced in GCC 5 that affects
conformance to the procedure call standard (AAPCS) has been fixed.

Many optimiser improvements

DWARF-5 support.

Many new and enhanced warnings.

Warnings about format strings now underline the pertinent part of
the string, and can offer suggested fixes.

Several new warnings related to buffer overflows and buffer
truncation.

New __builtin_add_overflow_p, __builtin_sub_overflow_p,
__builtin_mul_overflow_p built-ins added that test for overflow.

The C++ front end has experimental support for all of the current
C++17 draft.

The -fverbose-asm option has been expanded to prints comments
showing the source lines that correspond to the assembly.

The gcc and g++ driver programs will now provide suggestions for
misspelled arguments to command-line options.


AArch64 specific:

GCC has been updated to the latest revision of the procedure call
standard (AAPCS64) to provide support for parameter passing when
data types have been over-aligned.

The ARMv8.2-A and ARMv8.3-A architecture are now supported.

ARM specific:

Support for the ARMv5 and ARMv5E architectures has been
deprecated (which have no known implementations).

A new command-line option -mpure-code has been added. It does not
allow constant data to be placed in code sections.

x86 specific:

Support for the AVX-512 4FMAPS, 4VNNIW, VPOPCNTDQ and Software
Guard Extensions (SGX) ISA extensions has been added.

PPC specific:

GCC now diagnoses inline assembly that clobbers register r2.

RISC-V specific:

Support for the RISC-V instruction set has been added.

SH specific:

Support for SH5/SH64 has been removed.

Support for SH2A has been enhanced.

show more ...

import GCC 6.4.0. see this url for details which are too large to
include here:

http://gcc.gnu.org/gcc-6/changes.html

the main visible changes appear to be:

- The default mode for C++ is now -

import GCC 6.4.0. see this url for details which are too large to
include here:

http://gcc.gnu.org/gcc-6/changes.html

the main visible changes appear to be:

- The default mode for C++ is now -std=gnu++14 instead of -std=gnu++98.
- The C and C++ compilers now support attributes on enumerators.
- Diagnostics can now contain "fix-it hints"
- more warnings (some added to -Wall)

show more ...

import GCC 5.3.0. see these urls for details which are too large to
include here:

http://gcc.gnu.org/gcc-4.9/changes.html
http://gcc.gnu.org/gcc-5/changes.html

(note that GCC 5.x is a release st

import GCC 5.3.0. see these urls for details which are too large to
include here:

http://gcc.gnu.org/gcc-4.9/changes.html
http://gcc.gnu.org/gcc-5/changes.html

(note that GCC 5.x is a release stream like GCC 4.9.x, 4.8.x, etc.)


the main issues we will have are:

The default mode for C is now -std=gnu11 instead of -std=gnu89.

ARM:
The deprecated option -mwords-little-endian has been removed.
The options -mapcs, -mapcs-frame, -mtpcs-frame and -mtpcs-leaf-frame
which are only applicable to the old ABI have been deprecated.

MIPS:
The o32 ABI has been modified and extended. The o32 64-bit
floating-point register support is now obsolete and has been removed.
It has been replaced by three ABI extensions FPXX, FP64A, and FP64.
The meaning of the -mfp64 command-line option has changed. It is now
used to enable the FP64A and FP64 ABI extensions.

show more ...

import GCC 4.8 branch at r206687.

highlights from: http://gcc.gnu.org/gcc-4.6/changes.html

GCC now has stricter checks for invalid command-line options
New -Wunused-but-set-variable and -Wunu

import GCC 4.8 branch at r206687.

highlights from: http://gcc.gnu.org/gcc-4.6/changes.html

GCC now has stricter checks for invalid command-line options
New -Wunused-but-set-variable and -Wunused-but-set-parameter
warnings
Many platforms have been obsoleted
Link-time optimization improvements
A new switch -fstack-usage has been added
A new function attribute leaf was introduced
A new warning, enabled by -Wdouble-promotion
Support for selectively enabling and disabling warnings via
#pragma GCC diagnostic has been added
There is now experimental support for some features from the
upcoming C1X revision of the ISO C standard
Improved experimental support for the upcoming C++0x ISO C++
standard
G++ now issues clearer diagnostics in several cases
Updates for ARM, x86, MIPS, PPC/PPC64, SPARC
Darwin, FreeBSD, Solaris 2, MinGW and Cygwin now all support
__float128 on 32-bit and 64-bit x86 targets. [*1]

highlights from: http://gcc.gnu.org/gcc-4.7/changes.html

The -fconserve-space flag has been deprecated
Support for a new parameter --param case-values-threshold=n
was added
Interprocedural and Link-time optimization improvements
A new built-in, __builtin_assume_aligned, has been added
A new warning option -Wunused-local-typedefs was added
A new experimental command-line option -ftrack-macro-expansion
was added
Support for atomic operations specifying the C++11/C11 memory
model has been added
There is support for some more features from the C11 revision
of the ISO C standard
Improved experimental support for the new ISO C++ standard,
C++11
Updates for ARM, x86, MIPS, PPC/PPC64, SH, SPARC, TILE*
A new option (-grecord-gcc-switches) was added

highlights from: http://gcc.gnu.org/gcc-4.8/changes.html

GCC now uses C++ as its implementation language. This means
that to build GCC from sources, you will need a C++
compiler that understands C++ 2003
DWARF4 is now the default when generating DWARF debug
information
A new general optimization level, -Og, has been introduced
A new option -ftree-partial-pre was added
The option -fconserve-space has been removed
The command-line options -fipa-struct-reorg and
-fipa-matrix-reorg have been removed
Interprocedural and Link-time optimization improvements
AddressSanitizer, a fast memory error detector, has been
added [*2]
A new -Wsizeof-pointer-memaccess warning has been added
G++ now supports a -std=c++1y option for experimentation
with features proposed for the next revision of the
standard, expected around 2014
Improved experimental support for the new ISO C++ standard,
C++11
A new port has been added to support AArch64
Updates for ARM, x86, MIPS, PPC/PPC64, SH, SPARC, TILE*


[*1] we should support this too!
[*2] we should look into this.
https://code.google.com/p/address-sanitizer/

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