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authorH.J. Lu <hjl.tools@gmail.com>2017-06-09 05:13:15 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-06-09 05:13:31 -0700
commit2f5d20ac99b9434a634629282cbb46e2a8d56a1c (patch)
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parent990c32b93a29d8b8d599e10ebca19a260f84cbba (diff)
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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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diff --git a/ChangeLog b/ChangeLog
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+++ b/ChangeLog
@@ -1,3 +1,29 @@
+2017-06-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* 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.
+
 2017-06-09  Florian Weimer  <fweimer@redhat.com>
 
 	* malloc/Makefile (test-srcs): Remove tst-dynarray,