glibc/sysdeps/x86_64/multiarch/memmove.c
H.J. Lu 5f3d0b78e0 Use AVX unaligned memcpy only if AVX2 is available
memcpy with unaligned 256-bit AVX register loads/stores are slow on older
processorsl like Sandy Bridge.  This patch adds bit_AVX_Fast_Unaligned_Load
and sets it only when AVX2 is available.

	[BZ #17801]
	* sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features):
	Set the bit_AVX_Fast_Unaligned_Load bit for AVX2.
	* sysdeps/x86_64/multiarch/init-arch.h (bit_AVX_Fast_Unaligned_Load):
	New.
	(index_AVX_Fast_Unaligned_Load): Likewise.
	(HAS_AVX_FAST_UNALIGNED_LOAD): Likewise.
	* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check the
	bit_AVX_Fast_Unaligned_Load bit instead of the bit_AVX_Usable bit.
	* sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk): Likewise.
	* sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Likewise.
	* sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk): Likewise.
	* sysdeps/x86_64/multiarch/memmove.c (__libc_memmove): Replace
	HAS_AVX with HAS_AVX_FAST_UNALIGNED_LOAD.
	* sysdeps/x86_64/multiarch/memmove_chk.c (__memmove_chk): Likewise.
2015-01-30 15:37:58 -08:00

65 lines
2.2 KiB
C

/* Multiple versions of memmove.
All versions must be listed in ifunc-impl-list.c.
Copyright (C) 2010-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#if IS_IN (libc)
# define MEMMOVE __memmove_sse2
# ifdef SHARED
# undef libc_hidden_builtin_def
# define libc_hidden_builtin_def(name) \
__hidden_ver1 (__memmove_sse2, __GI_memmove, __memmove_sse2);
# endif
/* Redefine memmove so that the compiler won't complain about the type
mismatch with the IFUNC selector in strong_alias, below. */
# undef memmove
# define memmove __redirect_memmove
# include <string.h>
# undef memmove
extern __typeof (__redirect_memmove) __memmove_sse2 attribute_hidden;
extern __typeof (__redirect_memmove) __memmove_ssse3 attribute_hidden;
extern __typeof (__redirect_memmove) __memmove_ssse3_back attribute_hidden;
extern __typeof (__redirect_memmove) __memmove_avx_unaligned attribute_hidden;
#endif
#include "string/memmove.c"
#if IS_IN (libc)
# include <shlib-compat.h>
# include "init-arch.h"
/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
ifunc symbol properly. */
extern __typeof (__redirect_memmove) __libc_memmove;
libc_ifunc (__libc_memmove,
HAS_AVX_FAST_UNALIGNED_LOAD
? __memmove_avx_unaligned
: (HAS_SSSE3
? (HAS_FAST_COPY_BACKWARD
? __memmove_ssse3_back : __memmove_ssse3)
: __memmove_sse2));
strong_alias (__libc_memmove, memmove)
# if SHLIB_COMPAT (libc, GLIBC_2_2_5, GLIBC_2_14)
compat_symbol (libc, memmove, memcpy, GLIBC_2_2_5);
# endif
#endif