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5ac7aa1d7c
Optimize memrchr with AVX2 to search 32 bytes with a single vector compare instruction. It is as fast as SSE2 memrchr for small data sizes and up to 1X faster for large data sizes on Haswell. Select AVX2 memrchr on AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast. * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add memrchr-sse2 and memrchr-avx2. * sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Add tests for __memrchr_avx2 and __memrchr_sse2. * sysdeps/x86_64/multiarch/memrchr-avx2.S: New file. * sysdeps/x86_64/multiarch/memrchr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/memrchr.c: Likewise.
32 lines
1.2 KiB
C
32 lines
1.2 KiB
C
/* Multiple versions of memrchr
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All versions must be listed in ifunc-impl-list.c.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* Define multiple versions only for the definition in libc. */
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#if IS_IN (libc)
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# define memrchr __redirect_memrchr
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# include <string.h>
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# undef memrchr
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# define SYMBOL_NAME memrchr
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# include "ifunc-avx2.h"
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libc_ifunc_redirected (__redirect_memrchr, __memrchr, IFUNC_SELECTOR ());
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weak_alias (__memrchr, memrchr)
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#endif
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