[Bug string/19881] Improve x86-64 memset

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https://sourceware.org/bugzilla/show_bug.cgi?id=19881

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=85702d388d909d38f06c510c4504561df94d99bd

commit 85702d388d909d38f06c510c4504561df94d99bd
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Apr 1 14:01:24 2016 -0700

    X86-64: Add dummy memcopy.h and wordcopy.c

    Since x86-64 doesn't use memory copy functions, add dummy memcopy.h and
    wordcopy.c to reduce code size.  It reduces the size of libc.so by about
    1 KB.

        * sysdeps/x86_64/memcopy.h: New file.
        * sysdeps/x86_64/wordcopy.c: Likewise.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=550bdb5f6b24eb2422f0b0c3a4c81c4665f132ff

commit 550bdb5f6b24eb2422f0b0c3a4c81c4665f132ff
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Mar 31 12:46:57 2016 -0700

    X86-64: Remove previous default/SSE2/AVX2 memcpy/memmove

    Since the new SSE2/AVX2 memcpy/memmove are faster than the previous ones,
    we can remove the previous SSE2/AVX2 memcpy/memmove and replace them with
    the new ones.

    No change in IFUNC selection if SSE2 and AVX2 memcpy/memmove weren't used
    before.  If SSE2 or AVX2 memcpy/memmove were used, the new SSE2 or AVX2
    memcpy/memmove optimized with Enhanced REP MOVSB will be used for
    processors with ERMS.  The new AVX512 memcpy/memmove will be used for
    processors with AVX512 which prefer vzeroupper.

    Since the new SSE2 memcpy/memmove are faster than the previous default
    memcpy/memmove used in libc.a and ld.so, we also remove the previous
    default memcpy/memmove and make them the default memcpy/memmove, except
    that non-temporal store isn't used in ld.so.

    Together, it reduces the size of libc.so by about 6 KB and the size of
    ld.so by about 2 KB.

        [BZ #19776]
        * sysdeps/x86_64/memcpy.S: Make it dummy.
        * sysdeps/x86_64/mempcpy.S: Likewise.
        * sysdeps/x86_64/memmove.S: New file.
        * sysdeps/x86_64/memmove_chk.S: Likewise.
        * sysdeps/x86_64/multiarch/memmove.S: Likewise.
        * sysdeps/x86_64/multiarch/memmove_chk.S: Likewise.
        * sysdeps/x86_64/memmove.c: Removed.
        * sysdeps/x86_64/multiarch/memcpy-avx-unaligned.S: Likewise.
        * sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: Likewise.
        * sysdeps/x86_64/multiarch/memmove-avx-unaligned.S: Likewise.
        * sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S:
        Likewise.
        * sysdeps/x86_64/multiarch/memmove.c: Likewise.
        * sysdeps/x86_64/multiarch/memmove_chk.c: Likewise.
        * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Remove
        memcpy-sse2-unaligned, memmove-avx-unaligned,
        memcpy-avx-unaligned and memmove-sse2-unaligned-erms.
        * sysdeps/x86_64/multiarch/ifunc-impl-list.c
        (__libc_ifunc_impl_list): Replace
        __memmove_chk_avx512_unaligned_2 with
        __memmove_chk_avx512_unaligned.  Remove
        __memmove_chk_avx_unaligned_2.  Replace
        __memmove_chk_sse2_unaligned_2 with
        __memmove_chk_sse2_unaligned.  Remove __memmove_chk_sse2 and
        __memmove_avx_unaligned_2.  Replace __memmove_avx512_unaligned_2
        with __memmove_avx512_unaligned.  Replace
        __memmove_sse2_unaligned_2 with __memmove_sse2_unaligned.
        Remove __memmove_sse2.  Replace __memcpy_chk_avx512_unaligned_2
        with __memcpy_chk_avx512_unaligned.  Remove
        __memcpy_chk_avx_unaligned_2.  Replace
        __memcpy_chk_sse2_unaligned_2 with __memcpy_chk_sse2_unaligned.
        Remove __memcpy_chk_sse2.  Remove __memcpy_avx_unaligned_2.
        Replace __memcpy_avx512_unaligned_2 with
        __memcpy_avx512_unaligned.  Remove __memcpy_sse2_unaligned_2
        and __memcpy_sse2.  Replace __mempcpy_chk_avx512_unaligned_2
        with __mempcpy_chk_avx512_unaligned.  Remove
        __mempcpy_chk_avx_unaligned_2.  Replace
        __mempcpy_chk_sse2_unaligned_2 with
        __mempcpy_chk_sse2_unaligned.  Remove __mempcpy_chk_sse2.
        Replace __mempcpy_avx512_unaligned_2 with
        __mempcpy_avx512_unaligned.  Remove __mempcpy_avx_unaligned_2.
        Replace __mempcpy_sse2_unaligned_2 with
        __mempcpy_sse2_unaligned.  Remove __mempcpy_sse2.
        * sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Support
        __memcpy_avx512_unaligned_erms and __memcpy_avx512_unaligned.
        Use __memcpy_avx_unaligned_erms and __memcpy_sse2_unaligned_erms
        if processor has ERMS.  Default to __memcpy_sse2_unaligned.
        (ENTRY): Removed.
        (END): Likewise.
        (ENTRY_CHK): Likewise.
        (libc_hidden_builtin_def): Likewise.
        Don't include ../memcpy.S.
        * sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk): Support
        __memcpy_chk_avx512_unaligned_erms and
        __memcpy_chk_avx512_unaligned.  Use
        __memcpy_chk_avx_unaligned_erms and
        __memcpy_chk_sse2_unaligned_erms if if processor has ERMS.
        Default to __memcpy_chk_sse2_unaligned.
        * sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
        Change function suffix from unaligned_2 to unaligned.
        * sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Support
        __mempcpy_avx512_unaligned_erms and __mempcpy_avx512_unaligned.
        Use __mempcpy_avx_unaligned_erms and __mempcpy_sse2_unaligned_erms
        if processor has ERMS.  Default to __mempcpy_sse2_unaligned.
        (ENTRY): Removed.
        (END): Likewise.
        (ENTRY_CHK): Likewise.
        (libc_hidden_builtin_def): Likewise.
        Don't include ../mempcpy.S.
        (mempcpy): New.  Add a weak alias.
        * sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk): Support
        __mempcpy_chk_avx512_unaligned_erms and
        __mempcpy_chk_avx512_unaligned.  Use
        __mempcpy_chk_avx_unaligned_erms and
        __mempcpy_chk_sse2_unaligned_erms if if processor has ERMS.
        Default to __mempcpy_chk_sse2_unaligned.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1d96e81d73e27b2d243eab126433e24f4a4da2ef

commit 1d96e81d73e27b2d243eab126433e24f4a4da2ef
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Mar 31 10:42:30 2016 -0700

    X86-64: Remove the previous SSE2/AVX2 memsets

    Since the new SSE2/AVX2 memsets are faster than the previous ones, we
    can remove the previous SSE2/AVX2 memsets and replace them with the
    new ones.  This reduces the size of libc.so by about 900 bytes.

    No change in IFUNC selection if SSE2 and AVX2 memsets weren't used
    before.  If SSE2 or AVX2 memset was used, the new SSE2 or AVX2 memset
    optimized with Enhanced REP STOSB will be used for processors with
    ERMS.  The new AVX512 memset will be used for processors with AVX512
    which prefer vzeroupper.

        [BZ #19881]
        * sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S: Folded
        into ...
        * sysdeps/x86_64/memset.S: This.
        (__bzero): Removed.
        (__memset_tail): Likewise.
        (__memset_chk): Likewise.
        (memset): Likewise.
        (MEMSET_CHK_SYMBOL): New. Define only if MEMSET_SYMBOL isn't
        defined.
        (MEMSET_SYMBOL): Define only if MEMSET_SYMBOL isn't defined.
        * sysdeps/x86_64/multiarch/memset-avx2.S: Removed.
        (__memset_zero_constant_len_parameter): Check SHARED instead of
        PIC.
        * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Remove
        memset-avx2 and memset-sse2-unaligned-erms.
        * sysdeps/x86_64/multiarch/ifunc-impl-list.c
        (__libc_ifunc_impl_list): Remove __memset_chk_sse2,
        __memset_chk_avx2, __memset_sse2 and __memset_avx2_unaligned.
        * sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
        (__bzero): Enabled.
        * sysdeps/x86_64/multiarch/memset.S (memset): Replace
        __memset_sse2 and __memset_avx2 with __memset_sse2_unaligned
        and __memset_avx2_unaligned.  Use __memset_sse2_unaligned_erms
        or __memset_avx2_unaligned_erms if processor has ERMS.  Support
        __memset_avx512_unaligned_erms and __memset_avx512_unaligned.
        (memset): Removed.
        (__memset_chk): Likewise.
        (MEMSET_SYMBOL): New.
        (libc_hidden_builtin_def): Replace __memset_sse2 with
        __memset_sse2_unaligned.
        * sysdeps/x86_64/multiarch/memset_chk.S (__memset_chk): Replace
        __memset_chk_sse2 and __memset_chk_avx2 with
        __memset_chk_sse2_unaligned and __memset_chk_avx2_unaligned_erms.
        Use __memset_chk_sse2_unaligned_erms or
        __memset_chk_avx2_unaligned_erms if processor has ERMS.  Support
        __memset_chk_avx512_unaligned_erms and
        __memset_chk_avx512_unaligned.

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