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authorH.J. Lu <hjl.tools@gmail.com>2017-06-09 05:44:30 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-06-09 05:44:41 -0700
commit5ac7aa1d7cce8580f8225c33c819991abca102b9 (patch)
treea03a58010d692384042b6430b288e8197d77f1b4 /sysdeps/x86_64/multiarch/ifunc-impl-list.c
parent8fe57365bfb5a417d911ab715a5671b3b1d7b155 (diff)
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x86-64: Optimize memrchr with AVX2
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.
Diffstat (limited to 'sysdeps/x86_64/multiarch/ifunc-impl-list.c')
-rw-r--r--sysdeps/x86_64/multiarch/ifunc-impl-list.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 8dda1b040a..5670eb7e9e 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -112,6 +112,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, memmove, 1,
 			      __memmove_sse2_unaligned_erms))
 
+  /* Support sysdeps/x86_64/multiarch/memrchr.S.  */
+  IFUNC_IMPL (i, name, memrchr,
+	      IFUNC_IMPL_ADD (array, i, memrchr,
+			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      __memrchr_avx2)
+	      IFUNC_IMPL_ADD (array, i, memrchr, 1, __memrchr_sse2))
+
   /* Support sysdeps/x86_64/multiarch/memset_chk.S.  */
   IFUNC_IMPL (i, name, __memset_chk,
 	      IFUNC_IMPL_ADD (array, i, __memset_chk, 1,