[PATCH] Define _HAVE_STRING_ARCH_mempcpy to 1 for x86

[H.J. Lu]

Since x86 has an optimized mempcpy and GCC can inline mempcpy on x86,
define _HAVE_STRING_ARCH_mempcpy to 1 for x86.

If duplicated code between optimized memcpy and mempcpy is a concern,
we can add an entry point in memcpy and use it to implement mempcpy,
similar to the set of patches for __mempcpy_sse2_unaligned:

https://sourceware.org/ml/libc-alpha/2016-03/msg00166.html

OK for master?


H.J.
---
	[BZ #19759]
	* sysdeps/x86/bits/string.h (_HAVE_STRING_ARCH_mempcpy): New.
---
 sysdeps/x86/bits/string.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sysdeps/x86/bits/string.h b/sysdeps/x86/bits/string.h
index e4e019f..f5885b4 100644
--- a/sysdeps/x86/bits/string.h
+++ b/sysdeps/x86/bits/string.h
@@ -62,6 +62,9 @@
    | ((const unsigned char *) (src))[idx])
 
 
+/* Don't inline mempcpy into memcpy as x86 has an optimized mempcpy.  */
+# define _HAVE_STRING_ARCH_mempcpy 1
+
 /* Copy N bytes of SRC to DEST.  */
 # define _HAVE_STRING_ARCH_memcpy 1
 # define memcpy(dest, src, n) \
-- 
2.5.0