[Bug string/19907] Incorrect memcpy tests

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

https://sourceware.org/bugzilla/show_bug.cgi?id=19907

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The branch, hjl/benchtests/master has been created
        at  bf21eebd94019f333f6001ac304bf9907462a3fc (commit)

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=bf21eebd94019f333f6001ac304bf9907462a3fc

commit bf21eebd94019f333f6001ac304bf9907462a3fc
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sun Apr 3 17:21:45 2016 -0700

    X86-64: Use non-temporal store in memmove on large data

    memcpy/memmove benchmarks with large data shows that there is a
    regression with large data on Haswell machine.  non-temporal store
    in memmove on large data can improve performance significantly.  This
    patch adds a threshold to use non temporal store which is 4 times of
    shared cache size.  When size is above the threshold, non temporal
    store will be used.

    For size below 8 vector register width, we load all data into registers
    and store them together.  Only forward and backward loops, which move 4
    vector registers at a time, are used to support overlapping addresses.
    For forward loop, we load the last 4 vector register width of data and
    the first vector register width of data into vector registers before the
    loop and store them after the loop.  For backward loop, we load the first
    4 vector register width of data and the last vector register width of
    data into vector registers before the loop and store them after the loop.

        * sysdeps/x86_64/cacheinfo.c (__x86_shared_non_temporal_threshold):
        New.
        (init_cacheinfo): Set __x86_shared_non_temporal_threshold to
        4 times of shared cache size.
        * sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S
        (PREFETCHNT): New.
        (VMOVNT): Likewise.
        * sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S
        (PREFETCHNT): Likewise.
        (VMOVNT): Likewise.
        * sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S
        (PREFETCHNT): Likewise.
        (VMOVNT): Likewise.
        (VMOVU): Changed to movups for smaller code sizes.
        (VMOVA): Changed to movaps for smaller code sizes.
        * sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S: Update
        comments.  Rewrite to use forward and backward loops, which move
        4 vector registers at a time, to support overlapping addresses
        and use non temporal store if size is above the threshold.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2c90c17c112396b1ff51584ebef1f3005292fbc3

commit 2c90c17c112396b1ff51584ebef1f3005292fbc3
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Apr 4 09:38:30 2016 -0700

    Clear destination buffer set by the previous run

    Clear the destination buffer set by the previous run in test-memcpy.c
    and test-memmove.c to catch the error when the following implementations
    do copy anything.

        PR string/19907
        * string/test-memcpy.c (do_one_test): Clear the destination
        buffer set by the previous run.
        * string/test-memmove.c (do_one_test): Likewise.

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=410d4ffe105eefab7248d9e8f9840936393b6837

commit 410d4ffe105eefab7248d9e8f9840936393b6837
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Mar 30 09:18:27 2016 -0700

    Add memcpy/memmove/memset benchmarks with large data

    Add memcpy, memmove and memset benchmarks with large data sizes.

        * benchtests/Makefile (string-benchset): Add memcpy-large,
        memmove-large and memset-large.
        * benchtests/bench-memcpy-large.c: New file.
        * benchtests/bench-memmove-large.c: Likewise.
        * benchtests/bench-memmove-large.c: Likewise.
        * benchtests/bench-string.h (TIMEOUT): Don't redefine.

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