[Bug string/19776] Improve sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=19776

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d745a49ca39f47a701352b593151d8839dcba554

commit d745a49ca39f47a701352b593151d8839dcba554
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sun Mar 13 00:26:57 2016 -0800

    Add memmove/memset-avx512-unaligned-erms-no-vzeroupper.S

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a16432df8b46ce4db3f1b051ae61eda285833b42

commit a16432df8b46ce4db3f1b051ae61eda285833b42
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Mar 25 08:20:17 2016 -0700

    Add x86-64 memset with unaligned store and rep stosb

    Implement x86-64 memset with unaligned store and rep movsb.  Support
    16-byte, 32-byte and 64-byte vector register sizes.  A single file
    provides 2 implementations of memset, one with rep stosb and the other
    without rep stosb.  They share the same codes when size is between 2
    times of vector register size and REP_STOSB_THRESHOLD which is 1KB for
    16-byte vector register size and scaled up by larger vector register
    size.

    Key features:

    1. Use overlapping store to avoid branch.
    2. For size <= 4 times of vector register size, fully unroll the loop.
    3. For size > 4 times of vector register size, store 4 times of vector
    register size at a time.

        [BZ #19881]
        * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
        memset-sse2-unaligned-erms, memset-avx2-unaligned-erms and
        memset-avx512-unaligned-erms.
        * sysdeps/x86_64/multiarch/ifunc-impl-list.c
        (__libc_ifunc_impl_list): Test __memset_chk_sse2_unaligned,
        __memset_chk_sse2_unaligned_erms, __memset_chk_avx2_unaligned,
        __memset_chk_avx2_unaligned_erms, __memset_chk_avx512_unaligned,
        __memset_chk_avx512_unaligned_erms, __memset_sse2_unaligned,
        __memset_sse2_unaligned_erms, __memset_erms,
        __memset_avx2_unaligned, __memset_avx2_unaligned_erms,
        __memset_avx512_unaligned_erms and __memset_avx512_unaligned.
        * sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S: New
        file.
        * sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S:
        Likewise.
        * sysdeps/x86_64/multiarch/memset-sse2-unaligned-erms.S:
        Likewise.
        * sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S:
        Likewise.

    Memset

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=071b7236f96e0649e0728a83150f9fa52487563a

commit 071b7236f96e0649e0728a83150f9fa52487563a
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Mar 18 12:36:03 2016 -0700

    Add x86-64 memmove with unaligned load/store and rep movsb

    Implement x86-64 memmove with unaligned load/store and rep movsb.
    Support 16-byte, 32-byte and 64-byte vector register sizes.  When
    size <= 8 times of vector register size, there is no check for
    address overlap bewteen source and destination.  Since overhead for
    overlap check is small when size > 8 times of vector register size,
    memcpy is an alias of memmove.

    A single file provides 2 implementations of memmove, one with rep movsb
    and the other without rep movsb.  They share the same codes when size is
    between 2 times of vector register size and REP_MOVSB_THRESHOLD which
    is 2KB for 16-byte vector register size and scaled up by large vector
    register size.

    Key features:

    1. Use overlapping load and store to avoid branch.
    2. For size <= 8 times of vector register size, load  all sources into
    registers and store them together.
    3. If there is no address overlap bewteen source and destination, copy
    from both ends with 4 times of vector register size at a time.
    4. If address of destination > address of source, backward copy 8 times
    of vector register size at a time.
    5. Otherwise, forward copy 8 times of vector register size at a time.
    6. Use rep movsb only for forward copy.  Avoid slow backward rep movsb
    by fallbacking to backward copy 8 times of vector register size at a
    time.
    7. Skip when address of destination == address of source.

        [BZ #19776]
        * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
        memmove-sse2-unaligned-erms, memmove-avx-unaligned-erms and
        memmove-avx512-unaligned-erms.
        * sysdeps/x86_64/multiarch/ifunc-impl-list.c
        (__libc_ifunc_impl_list): Test
        __memmove_chk_avx512_unaligned_2,
        __memmove_chk_avx512_unaligned_erms,
        __memmove_chk_avx_unaligned_2, __memmove_chk_avx_unaligned_erms,
        __memmove_chk_sse2_unaligned_2,
        __memmove_chk_sse2_unaligned_erms, __memmove_avx_unaligned_2,
        __memmove_avx_unaligned_erms, __memmove_avx512_unaligned_2,
        __memmove_avx512_unaligned_erms, __memmove_erms,
        __memmove_sse2_unaligned_2, __memmove_sse2_unaligned_erms,
        __memcpy_chk_avx512_unaligned_2,
        __memcpy_chk_avx512_unaligned_erms,
        __memcpy_chk_avx_unaligned_2, __memcpy_chk_avx_unaligned_erms,
        __memcpy_chk_sse2_unaligned_2, __memcpy_chk_sse2_unaligned_erms,
        __memcpy_avx_unaligned_2, __memcpy_avx_unaligned_erms,
        __memcpy_avx512_unaligned_2, __memcpy_avx512_unaligned_erms,
        __memcpy_sse2_unaligned_2, __memcpy_sse2_unaligned_erms,
        __memcpy_erms, __mempcpy_chk_avx512_unaligned_2,
        __mempcpy_chk_avx512_unaligned_erms,
        __mempcpy_chk_avx_unaligned_2, __mempcpy_chk_avx_unaligned_erms,
        __mempcpy_chk_sse2_unaligned_2, __mempcpy_chk_sse2_unaligned_erms,
        __mempcpy_avx512_unaligned_2, __mempcpy_avx512_unaligned_erms,
        __mempcpy_avx_unaligned_2, __mempcpy_avx_unaligned_erms,
        __mempcpy_sse2_unaligned_2, __mempcpy_sse2_unaligned_erms and
        __mempcpy_erms.
        * sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S: New
        file.
        * sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S:
        Likwise.
        * sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S:
        Likwise.
        * sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
        Likwise.

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