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| author | H.J. Lu <hjl.tools@gmail.com> | 2017-06-09 05:13:15 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2017-06-09 05:13:31 -0700 |
| commit | 2f5d20ac99b9434a634629282cbb46e2a8d56a1c (patch) | |
| tree | 6a9dcdd8346cd5ad6473b165a404c9961359c6ed /sysdeps/x86_64/sub_n.S | |
| parent | 990c32b93a29d8b8d599e10ebca19a260f84cbba (diff) | |
| download | glibc-2f5d20ac99b9434a634629282cbb46e2a8d56a1c.tar.gz glibc-2f5d20ac99b9434a634629282cbb46e2a8d56a1c.tar.xz glibc-2f5d20ac99b9434a634629282cbb46e2a8d56a1c.zip | |
x86-64: Optimize memchr/rawmemchr/wmemchr with SSE2/AVX2
SSE2 memchr is extended to support wmemchr. AVX2 memchr/rawmemchr/wmemchr are added to search 32 bytes with a single vector compare instruction. AVX2 memchr/rawmemchr/wmemchr are as fast as SSE2 memchr/rawmemchr/wmemchr for small sizes and up to 1.5X faster for larger sizes on Haswell and Skylake. Select AVX2 memchr/rawmemchr/wmemchr on AVX2 machines where vzeroupper is preferred and AVX unaligned load is fast. NB: It uses TZCNT instead of BSF since TZCNT produces the same result as BSF for non-zero input. TZCNT is faster than BSF and is executed as BSF if machine doesn't support TZCNT. * sysdeps/x86_64/memchr.S (MEMCHR): New. Depending on if USE_AS_WMEMCHR is defined. (PCMPEQ): Likewise. (memchr): Renamed to ... (MEMCHR): This. Support wmemchr if USE_AS_WMEMCHR is defined. Replace pcmpeqb with PCMPEQ. * sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add memchr-sse2, rawmemchr-sse2, memchr-avx2, rawmemchr-avx2, wmemchr-sse4_1, wmemchr-avx2 and wmemchr-c. * sysdeps/x86_64/multiarch/ifunc-avx2.h: New file. * sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise. * sysdeps/x86_64/multiarch/memchr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/memchr.c: Likewise. * sysdeps/x86_64/multiarch/rawmemchr-avx2.S: Likewise. * sysdeps/x86_64/multiarch/rawmemchr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/rawmemchr.c: Likewise. * sysdeps/x86_64/multiarch/wmemchr-avx2.S: Likewise. * sysdeps/x86_64/multiarch/wmemchr-sse2.S: Likewise. * sysdeps/x86_64/multiarch/wmemchr.c: Likewise. * sysdeps/x86_64/multiarch/ifunc-impl-list.c (__libc_ifunc_impl_list): Test __memchr_avx2, __memchr_sse2, __rawmemchr_avx2, __rawmemchr_sse2, __wmemchr_avx2 and __wmemchr_sse2.
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