glibc/sysdeps/x86_64/multiarch/mempcpy.S
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

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ArmAsm

/* Multiple versions of mempcpy
All versions must be listed in ifunc-impl-list.c.
Copyright (C) 2010-2015 Free Software Foundation, Inc.
Contributed by Intel Corporation.
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/>. */
#include <sysdep.h>
#include <init-arch.h>
/* Define multiple versions only for the definition in lib and for
DSO. In static binaries we need mempcpy before the initialization
happened. */
#if defined SHARED && IS_IN (libc)
ENTRY(__mempcpy)
.type __mempcpy, @gnu_indirect_function
cmpl $0, KIND_OFFSET+__cpu_features(%rip)
jne 1f
call __init_cpu_features
1: leaq __mempcpy_sse2(%rip), %rax
testl $bit_SSSE3, __cpu_features+CPUID_OFFSET+index_SSSE3(%rip)
jz 2f
leaq __mempcpy_ssse3(%rip), %rax
testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
jz 2f
leaq __mempcpy_ssse3_back(%rip), %rax
testl $bit_AVX_Fast_Unaligned_Load, __cpu_features+FEATURE_OFFSET+index_AVX_Fast_Unaligned_Load(%rip)
jz 2f
leaq __mempcpy_avx_unaligned(%rip), %rax
2: ret
END(__mempcpy)
# undef ENTRY
# define ENTRY(name) \
.type __mempcpy_sse2, @function; \
.p2align 4; \
.globl __mempcpy_sse2; \
.hidden __mempcpy_sse2; \
__mempcpy_sse2: cfi_startproc; \
CALL_MCOUNT
# undef END
# define END(name) \
cfi_endproc; .size __mempcpy_sse2, .-__mempcpy_sse2
# undef ENTRY_CHK
# define ENTRY_CHK(name) \
.type __mempcpy_chk_sse2, @function; \
.globl __mempcpy_chk_sse2; \
.p2align 4; \
__mempcpy_chk_sse2: cfi_startproc; \
CALL_MCOUNT
# undef END_CHK
# define END_CHK(name) \
cfi_endproc; .size __mempcpy_chk_sse2, .-__mempcpy_chk_sse2
# undef libc_hidden_def
# undef libc_hidden_builtin_def
/* It doesn't make sense to send libc-internal mempcpy calls through a PLT.
The speedup we get from using SSSE3 instruction is likely eaten away
by the indirect call in the PLT. */
# define libc_hidden_def(name) \
.globl __GI_mempcpy; __GI_mempcpy = __mempcpy_sse2
# define libc_hidden_builtin_def(name) \
.globl __GI___mempcpy; __GI___mempcpy = __mempcpy_sse2
#endif
#include "../mempcpy.S"