Add x86-64 memmove with unaligned load/store and rep movsb

Implement x86-64 memmove with unaligned load/store and rep movsb.
Support 16-byte, 32-byte and 64-byte vector register sizes.  When
size <= 8 times of vector register size, there is no check for
address overlap bewteen source and destination.  Since overhead for
overlap check is small when size > 8 times of vector register size,
memcpy is an alias of memmove.

A single file provides 2 implementations of memmove, one with rep movsb
and the other without rep movsb.  They share the same codes when size is
between 2 times of vector register size and REP_MOVSB_THRESHOLD which
is 2KB for 16-byte vector register size and scaled up by large vector
register size.

Key features:

1. Use overlapping load and store to avoid branch.
2. For size <= 8 times of vector register size, load  all sources into
registers and store them together.
3. If there is no address overlap bewteen source and destination, copy
from both ends with 4 times of vector register size at a time.
4. If address of destination > address of source, backward copy 8 times
of vector register size at a time.
5. Otherwise, forward copy 8 times of vector register size at a time.
6. Use rep movsb only for forward copy.  Avoid slow backward rep movsb
by fallbacking to backward copy 8 times of vector register size at a
time.
7. Skip when address of destination == address of source.

	[BZ #19776]
	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
	memmove-sse2-unaligned-erms, memmove-avx-unaligned-erms and
	memmove-avx512-unaligned-erms.
	* sysdeps/x86_64/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Test
	__memmove_chk_avx512_unaligned_2,
	__memmove_chk_avx512_unaligned_erms,
	__memmove_chk_avx_unaligned_2, __memmove_chk_avx_unaligned_erms,
	__memmove_chk_sse2_unaligned_2,
	__memmove_chk_sse2_unaligned_erms, __memmove_avx_unaligned_2,
	__memmove_avx_unaligned_erms, __memmove_avx512_unaligned_2,
	__memmove_avx512_unaligned_erms, __memmove_erms,
	__memmove_sse2_unaligned_2, __memmove_sse2_unaligned_erms,
	__memcpy_chk_avx512_unaligned_2,
	__memcpy_chk_avx512_unaligned_erms,
	__memcpy_chk_avx_unaligned_2, __memcpy_chk_avx_unaligned_erms,
	__memcpy_chk_sse2_unaligned_2, __memcpy_chk_sse2_unaligned_erms,
	__memcpy_avx_unaligned_2, __memcpy_avx_unaligned_erms,
	__memcpy_avx512_unaligned_2, __memcpy_avx512_unaligned_erms,
	__memcpy_sse2_unaligned_2, __memcpy_sse2_unaligned_erms,
	__memcpy_erms, __mempcpy_chk_avx512_unaligned_2,
	__mempcpy_chk_avx512_unaligned_erms,
	__mempcpy_chk_avx_unaligned_2, __mempcpy_chk_avx_unaligned_erms,
	__mempcpy_chk_sse2_unaligned_2, __mempcpy_chk_sse2_unaligned_erms,
	__mempcpy_avx512_unaligned_2, __mempcpy_avx512_unaligned_erms,
	__mempcpy_avx_unaligned_2, __mempcpy_avx_unaligned_erms,
	__mempcpy_sse2_unaligned_2, __mempcpy_sse2_unaligned_erms and
	__mempcpy_erms.
	* sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S: New
	file.
	* sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S:
	Likwise.
	* sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S:
	Likwise.
	* sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:
	Likwise.

6 files changed, 594 insertions, 1 deletions

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 7fc89c2..ef4dbc0 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -20,7 +20,10 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 \
 		   strcat-sse2-unaligned strncat-sse2-unaligned \
 		   strchr-sse2-no-bsf memcmp-ssse3 strstr-sse2-unaligned \
 		   strcspn-c strpbrk-c strspn-c varshift memset-avx2 \
-		   memset-avx512-no-vzeroupper
+		   memset-avx512-no-vzeroupper \
+		   memmove-sse2-unaligned-erms \
+		   memmove-avx-unaligned-erms \
+		   memmove-avx512-unaligned-erms
 CFLAGS-varshift.c += -msse4
 CFLAGS-strcspn-c.c += -msse4
 CFLAGS-strpbrk-c.c += -msse4
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 188b6d3..9204da4 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -52,17 +52,33 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __memmove_chk_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memmove_chk_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memmove_chk_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __memmove_chk_avx_unaligned)
 	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memmove_chk_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memmove_chk_avx_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __memmove_chk_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, __memmove_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __memmove_chk_ssse3)
 	      IFUNC_IMPL_ADD (array, i, __memmove_chk, 1,
+			      __memmove_chk_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk, 1,
+			      __memmove_chk_sse2_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __memmove_chk, 1,
 			      __memmove_chk_sse2))
 
   /* Support sysdeps/x86_64/multiarch/memmove.S.  */
@@ -70,15 +86,32 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, memmove,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __memmove_avx_unaligned)
+	      IFUNC_IMPL_ADD (array, i, memmove,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memmove_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memmove,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memmove_avx_unaligned_erms)
 #ifdef HAVE_AVX512_ASM_SUPPORT
 	      IFUNC_IMPL_ADD (array, i, memmove,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __memmove_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, memmove,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memmove_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memmove,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memmove_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, memmove, HAS_CPU_FEATURE (SSSE3),
 			      __memmove_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, memmove, HAS_CPU_FEATURE (SSSE3),
 			      __memmove_ssse3)
+	      IFUNC_IMPL_ADD (array, i, memmove, 1, __memmove_erms)
+	      IFUNC_IMPL_ADD (array, i, memmove, 1,
+			      __memmove_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memmove, 1,
+			      __memmove_sse2_unaligned_erms)
 	      IFUNC_IMPL_ADD (array, i, memmove, 1, __memmove_sse2))
 
   /* Support sysdeps/x86_64/multiarch/memset_chk.S.  */
@@ -267,17 +300,33 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __memcpy_chk_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memcpy_chk_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memcpy_chk_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __memcpy_chk_avx_unaligned)
 	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memcpy_chk_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memcpy_chk_avx_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __memcpy_chk_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, __memcpy_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __memcpy_chk_ssse3)
 	      IFUNC_IMPL_ADD (array, i, __memcpy_chk, 1,
+			      __memcpy_chk_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk, 1,
+			      __memcpy_chk_sse2_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __memcpy_chk, 1,
 			      __memcpy_chk_sse2))
 
   /* Support sysdeps/x86_64/multiarch/memcpy.S.  */
@@ -285,6 +334,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, memcpy,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __memcpy_avx_unaligned)
+	      IFUNC_IMPL_ADD (array, i, memcpy,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memcpy_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memcpy,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __memcpy_avx_unaligned_erms)
 	      IFUNC_IMPL_ADD (array, i, memcpy, HAS_CPU_FEATURE (SSSE3),
 			      __memcpy_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, memcpy, HAS_CPU_FEATURE (SSSE3),
@@ -293,8 +348,19 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, memcpy,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __memcpy_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, memcpy,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memcpy_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memcpy,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __memcpy_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_sse2_unaligned)
+	      IFUNC_IMPL_ADD (array, i, memcpy, 1,
+			      __memcpy_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, memcpy, 1,
+			      __memcpy_sse2_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_erms)
 	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_sse2))
 
   /* Support sysdeps/x86_64/multiarch/mempcpy_chk.S.  */
@@ -303,17 +369,33 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __mempcpy_chk_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __mempcpy_chk_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __mempcpy_chk_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __mempcpy_chk_avx_unaligned)
 	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __mempcpy_chk_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __mempcpy_chk_avx_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __mempcpy_chk_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk,
 			      HAS_CPU_FEATURE (SSSE3),
 			      __mempcpy_chk_ssse3)
 	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk, 1,
+			      __mempcpy_chk_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk, 1,
+			      __mempcpy_chk_sse2_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, __mempcpy_chk, 1,
 			      __mempcpy_chk_sse2))
 
   /* Support sysdeps/x86_64/multiarch/mempcpy.S.  */
@@ -322,14 +404,31 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, mempcpy,
 			      HAS_ARCH_FEATURE (AVX512F_Usable),
 			      __mempcpy_avx512_no_vzeroupper)
+	      IFUNC_IMPL_ADD (array, i, mempcpy,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __mempcpy_avx512_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, mempcpy,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __mempcpy_avx512_unaligned_erms)
 #endif
 	      IFUNC_IMPL_ADD (array, i, mempcpy,
 			      HAS_ARCH_FEATURE (AVX_Usable),
 			      __mempcpy_avx_unaligned)
+	      IFUNC_IMPL_ADD (array, i, mempcpy,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __mempcpy_avx_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, mempcpy,
+			      HAS_ARCH_FEATURE (AVX_Usable),
+			      __mempcpy_avx_unaligned_erms)
 	      IFUNC_IMPL_ADD (array, i, mempcpy, HAS_CPU_FEATURE (SSSE3),
 			      __mempcpy_ssse3_back)
 	      IFUNC_IMPL_ADD (array, i, mempcpy, HAS_CPU_FEATURE (SSSE3),
 			      __mempcpy_ssse3)
+	      IFUNC_IMPL_ADD (array, i, mempcpy, 1,
+			      __mempcpy_sse2_unaligned_2)
+	      IFUNC_IMPL_ADD (array, i, mempcpy, 1,
+			      __mempcpy_sse2_unaligned_erms)
+	      IFUNC_IMPL_ADD (array, i, mempcpy, 1, __mempcpy_erms)
 	      IFUNC_IMPL_ADD (array, i, mempcpy, 1, __mempcpy_sse2))
 
   /* Support sysdeps/x86_64/multiarch/strncmp.S.  */
diff --git a/sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S
new file mode 100644
index 0000000..3a72c7e
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memmove-avx-unaligned-erms.S
@@ -0,0 +1,9 @@
+#define VEC_SIZE	32
+#define VEC(i)		ymm##i
+#define VMOVU		vmovdqu
+#define VMOVA		vmovdqa
+
+#define SECTION(p)		p##.avx
+#define MEMMOVE_SYMBOL(p,s)	p##_avx_##s
+
+#include "memmove-vec-unaligned-erms.S"
diff --git a/sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S
new file mode 100644
index 0000000..38358fa
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memmove-avx512-unaligned-erms.S
@@ -0,0 +1,11 @@
+#ifdef HAVE_AVX512_ASM_SUPPORT
+# define VEC_SIZE	64
+# define VEC(i)		zmm##i
+# define VMOVU		vmovdqu64
+# define VMOVA		vmovdqa64
+
+# define SECTION(p)		p##.avx512
+# define MEMMOVE_SYMBOL(p,s)	p##_avx512_##s
+
+# include "memmove-vec-unaligned-erms.S"
+#endif
diff --git a/sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S
new file mode 100644
index 0000000..52b9ae0
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memmove-sse2-unaligned-erms.S
@@ -0,0 +1,9 @@
+#define VEC_SIZE	16
+#define VEC(i)		xmm##i
+#define VMOVU		movdqu
+#define VMOVA		movdqa
+
+#define SECTION(p)		p
+#define MEMMOVE_SYMBOL(p,s)	p##_sse2_##s
+
+#include "memmove-vec-unaligned-erms.S"
diff --git a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
new file mode 100644
index 0000000..cf645dd
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
@@ -0,0 +1,462 @@
+/* memmove/memcpy/mempcpy with unaligned load/store and rep movsb
+   Copyright (C) 2016 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/>.  */
+
+/* memmove/memcpy/mempcpy is implemented as:
+   1. Use overlapping load and store to avoid branch.
+   2. Use 8-bit or 32-bit displacements for branches and nop paddings
+      to avoid long nop between instructions.
+   3. Load all sources into registers and store them together to avoid
+      possible address overflap between source and destination.
+   4. If size is 2 * VEC_SIZE or less, load all sources into registers
+      and store them together.
+   5. If there is no address overflap, copy from both ends with
+      4 * VEC_SIZE at a time.
+   6. If size is 8 * VEC_SIZE or less, load all sources into registers
+      and store them together.
+   7. If address of destination > address of source, backward copy
+      8 * VEC_SIZE at a time.
+   8. Otherwise, forward copy 8 * VEC_SIZE at a time.  */
+
+#if IS_IN (libc)
+
+# include <sysdep.h>
+# include "asm-syntax.h"
+
+# ifndef VZEROUPPER
+#  if VEC_SIZE > 16
+#   define VZEROUPPER vzeroupper
+#  else
+#   define VZEROUPPER
+#  endif
+# endif
+
+/* Threshold to use Enhanced REP MOVSB.  Since there is overhead to set
+   up REP MOVSB operation, REP MOVSB isn't faster on short data.  The
+   memcpy micro benchmark in glibc shows that 2KB is the approximate
+   value above which REP MOVSB becomes faster than SSE2 optimization
+   on processors with Enhanced REP MOVSB.  Since larger register size
+   can move more data with a single load and store, the threshold is
+   higher with larger register size.  */
+# ifndef REP_MOVSB_THRESHOLD
+#  define REP_MOVSB_THRESHOLD	(2048 * (VEC_SIZE / 16))
+# endif
+
+# ifndef SECTION
+#  error SECTION is not defined!
+# endif
+	.section SECTION(.text),"ax",@progbits
+
+# ifdef SHARED
+ENTRY (MEMMOVE_SYMBOL (__mempcpy_chk, unaligned_2))
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END (MEMMOVE_SYMBOL (__mempcpy_chk, unaligned_2))
+
+ENTRY (MEMMOVE_SYMBOL (__mempcpy, unaligned_2))
+	movq	%rdi, %rax
+	addq	%rdx, %rax
+	jmp	L(start)
+END (MEMMOVE_SYMBOL (__mempcpy, unaligned_2))
+
+ENTRY (MEMMOVE_SYMBOL (__memmove_chk, unaligned_2))
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END (MEMMOVE_SYMBOL (__memmove_chk, unaligned_2))
+# endif
+
+ENTRY (MEMMOVE_SYMBOL (__memmove, unaligned_2))
+	movq	%rdi, %rax
+L(start):
+	cmpq	$VEC_SIZE, %rdx
+	jb	L(less_vec)
+	cmpq	$(VEC_SIZE * 2), %rdx
+	ja	L(more_2x_vec)
+	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE.  */
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	-VEC_SIZE(%rsi,%rdx), %VEC(1)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), -VEC_SIZE(%rdi,%rdx)
+	VZEROUPPER
+	ret
+END (MEMMOVE_SYMBOL (__memmove, unaligned_2))
+
+# ifdef SHARED
+ENTRY (MEMMOVE_SYMBOL (__mempcpy_chk, unaligned_erms))
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END (MEMMOVE_SYMBOL (__mempcpy_chk, unaligned_erms))
+# endif
+
+ENTRY (MEMMOVE_SYMBOL (__mempcpy, unaligned_erms))
+	movq	%rdi, %rax
+	addq	%rdx, %rax
+	jmp	L(start_erms)
+END (MEMMOVE_SYMBOL (__mempcpy, unaligned_erms))
+
+# ifdef SHARED
+ENTRY (MEMMOVE_SYMBOL (__memmove_chk, unaligned_erms))
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END (MEMMOVE_SYMBOL (__memmove_chk, unaligned_erms))
+# endif
+
+# if VEC_SIZE == 16
+/* Only used to measure performance of REP MOVSB.  */
+#  ifdef SHARED
+ENTRY (__mempcpy_erms)
+	movq	%rdi, %rax
+	addq	%rdx, %rax
+	jmp	L(movsb)
+END (__mempcpy_erms)
+#  endif
+
+ENTRY (__memmove_erms)
+	movq	%rdi, %rax
+	movq	%rdx, %rcx
+	cmpq	%rsi, %rdi
+	jbe	1f
+	leaq	(%rsi,%rcx), %rdx
+	cmpq	%rdx, %rdi
+	jb	L(movsb_backward)
+1:
+	rep movsb
+	ret
+L(movsb_backward):
+	leaq	-1(%rdi,%rcx), %rdi
+	leaq	-1(%rsi,%rcx), %rsi
+	std
+	rep movsb
+	cld
+	ret
+END (__memmove_erms)
+strong_alias (__memmove_erms, __memcpy_erms)
+# endif
+
+ENTRY (MEMMOVE_SYMBOL (__memmove, unaligned_erms))
+	movq	%rdi, %rax
+L(start_erms):
+	cmpq	$VEC_SIZE, %rdx
+	jb	L(less_vec)
+	cmpq	$(VEC_SIZE * 2), %rdx
+	ja	L(movsb_more_2x_vec)
+L(last_2x_vec):
+	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE. */
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	-VEC_SIZE(%rsi,%rdx), %VEC(1)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), -VEC_SIZE(%rdi,%rdx)
+L(return):
+	VZEROUPPER
+	ret
+
+L(movsb):
+	cmpq	%rsi, %rdi
+	je	L(nop)
+	jb	1f
+	leaq	(%rsi,%rdx), %r9
+	cmpq	%r9, %rdi
+	/* Avoid slow backward REP MOVSB.  */
+# if REP_MOVSB_THRESHOLD <= (VEC_SIZE * 8)
+#  error Unsupported REP_MOVSB_THRESHOLD and VEC_SIZE!
+# endif
+	jb	L(more_8x_vec_backward)
+1:
+	movq	%rdx, %rcx
+	rep movsb
+L(nop):
+	ret
+
+	.p2align 4
+L(movsb_more_2x_vec):
+	cmpq	$REP_MOVSB_THRESHOLD, %rdx
+	/* Force 32-bit displacement to avoid long nop between
+	   instructions.  */
+	ja.d32	L(movsb)
+	.p2align 4
+L(more_2x_vec):
+	/* More than 2 * VEC.  */
+	cmpq	%rsi, %rdi
+	je	L(nop)
+	jb	L(copy_forward)
+	leaq	(%rsi,%rdx), %rcx
+	cmpq	%rcx, %rdi
+	jb	L(more_2x_vec_overlap)
+L(copy_forward):
+	leaq	(%rdi,%rdx), %rcx
+	cmpq	%rcx, %rsi
+	jb	L(more_2x_vec_overlap)
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	VEC_SIZE(%rsi), %VEC(1)
+	VMOVU	-VEC_SIZE(%rsi,%rdx), %VEC(2)
+	VMOVU	-(VEC_SIZE * 2)(%rsi,%rdx), %VEC(3)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), VEC_SIZE(%rdi)
+	VMOVU	%VEC(2), -VEC_SIZE(%rdi,%rdx)
+	VMOVU	%VEC(3), -(VEC_SIZE * 2)(%rdi,%rdx)
+	cmpq	$(VEC_SIZE * 4), %rdx
+	/* Force 32-bit displacement to avoid long nop between
+	   instructions.  */
+	jbe.d32	L(return)
+	VMOVU	(VEC_SIZE * 2)(%rsi), %VEC(0)
+	VMOVU	(VEC_SIZE * 3)(%rsi), %VEC(1)
+	VMOVU	-(VEC_SIZE * 3)(%rsi,%rdx), %VEC(2)
+	VMOVU	-(VEC_SIZE * 4)(%rsi,%rdx), %VEC(3)
+	VMOVU	%VEC(0), (VEC_SIZE * 2)(%rdi)
+	VMOVU	%VEC(1), (VEC_SIZE * 3)(%rdi)
+	VMOVU	%VEC(2), -(VEC_SIZE * 3)(%rdi,%rdx)
+	VMOVU	%VEC(3), -(VEC_SIZE * 4)(%rdi,%rdx)
+	cmpq	$(VEC_SIZE * 8), %rdx
+# if  VEC_SIZE == 16
+	jbe	L(return)
+# else
+	/* Use 8-bit displacement to avoid long nop between
+	   instructions.  */
+	jbe	L(return_disp8)
+# endif
+	leaq	(VEC_SIZE * 4)(%rdi), %rcx
+	addq	%rdi, %rdx
+	andq	$-(VEC_SIZE * 4), %rdx
+	andq	$-(VEC_SIZE * 4), %rcx
+	movq	%rcx, %r11
+	subq	%rdi, %r11
+	addq	%r11, %rsi
+	cmpq	%rdx, %rcx
+	/* Use 8-bit displacement to avoid long nop between
+	   instructions.  */
+	je	L(return_disp8)
+	movq	%rsi, %r10
+	subq	%rcx, %r10
+	leaq	VEC_SIZE(%r10), %r9
+	leaq	(VEC_SIZE * 2)(%r10), %r8
+	leaq	(VEC_SIZE * 3)(%r10), %r11
+	.p2align 4
+L(loop):
+	VMOVU	(%rcx,%r10), %VEC(0)
+	VMOVU	(%rcx,%r9), %VEC(1)
+	VMOVU	(%rcx,%r8), %VEC(2)
+	VMOVU	(%rcx,%r11), %VEC(3)
+	VMOVA	%VEC(0), (%rcx)
+	VMOVA	%VEC(1), VEC_SIZE(%rcx)
+	VMOVA	%VEC(2), (VEC_SIZE * 2)(%rcx)
+	VMOVA	%VEC(3), (VEC_SIZE * 3)(%rcx)
+	addq	$(VEC_SIZE * 4), %rcx
+	cmpq	%rcx, %rdx
+	jne	L(loop)
+L(return_disp8):
+	VZEROUPPER
+	ret
+L(less_vec):
+	/* Less than 1 VEC.  */
+# if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64
+#  error Unsupported VEC_SIZE!
+# endif
+# if VEC_SIZE > 32
+	cmpb	$32, %dl
+	jae	L(between_32_63)
+# endif
+# if VEC_SIZE > 16
+	cmpb	$16, %dl
+	jae	L(between_16_31)
+# endif
+	cmpb	$8, %dl
+	jae	L(between_8_15)
+	cmpb	$4, %dl
+	jae	L(between_4_7)
+	cmpb	$1, %dl
+	ja	L(between_2_3)
+	jb	1f
+	movzbl	(%rsi), %ecx
+	movb	%cl, (%rdi)
+1:
+	ret
+# if VEC_SIZE > 32
+L(between_32_63):
+	/* From 32 to 63.  No branch when size == 32.  */
+	vmovdqu	(%rsi), %ymm0
+	vmovdqu	-32(%rsi,%rdx), %ymm1
+	vmovdqu	%ymm0, (%rdi)
+	vmovdqu	%ymm1, -32(%rdi,%rdx)
+	VZEROUPPER
+	ret
+# endif
+# if VEC_SIZE > 16
+	/* From 16 to 31.  No branch when size == 16.  */
+L(between_16_31):
+	vmovdqu	(%rsi), %xmm0
+	vmovdqu	-16(%rsi,%rdx), %xmm1
+	vmovdqu	%xmm0, (%rdi)
+	vmovdqu	%xmm1, -16(%rdi,%rdx)
+	ret
+# endif
+L(between_8_15):
+	/* From 8 to 15.  No branch when size == 8.  */
+	movq	-8(%rsi,%rdx), %rcx
+	movq	(%rsi), %rsi
+	movq	%rcx, -8(%rdi,%rdx)
+	movq	%rsi, (%rdi)
+	ret
+L(between_4_7):
+	/* From 4 to 7.  No branch when size == 4.  */
+	movl	-4(%rsi,%rdx), %ecx
+	movl	(%rsi), %esi
+	movl	%ecx, -4(%rdi,%rdx)
+	movl	%esi, (%rdi)
+	ret
+L(between_2_3):
+	/* From 2 to 3.  No branch when size == 2.  */
+	movzwl	-2(%rsi,%rdx), %ecx
+	movzwl	(%rsi), %esi
+	movw	%cx, -2(%rdi,%rdx)
+	movw	%si, (%rdi)
+	ret
+
+# if VEC_SIZE > 16
+	/* Align to 16 bytes to avoid long nop between instructions.  */
+	.p2align 4
+# endif
+L(more_2x_vec_overlap):
+	/* More than 2 * VEC and there is overlap bewteen destination
+	   and source.  */
+	cmpq	$(VEC_SIZE * 8), %rdx
+	ja	L(more_8x_vec)
+	cmpq	$(VEC_SIZE * 4), %rdx
+	jb	L(last_4x_vec)
+L(between_4x_vec_and_8x_vec):
+	/* Copy from 4 * VEC to 8 * VEC, inclusively. */
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	VEC_SIZE(%rsi), %VEC(1)
+	VMOVU	(VEC_SIZE * 2)(%rsi), %VEC(2)
+	VMOVU	(VEC_SIZE * 3)(%rsi), %VEC(3)
+	VMOVU	-VEC_SIZE(%rsi,%rdx), %VEC(4)
+	VMOVU	-(VEC_SIZE * 2)(%rsi,%rdx), %VEC(5)
+	VMOVU	-(VEC_SIZE * 3)(%rsi,%rdx), %VEC(6)
+	VMOVU	-(VEC_SIZE * 4)(%rsi,%rdx), %VEC(7)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), VEC_SIZE(%rdi)
+	VMOVU	%VEC(2), (VEC_SIZE * 2)(%rdi)
+	VMOVU	%VEC(3), (VEC_SIZE * 3)(%rdi)
+	VMOVU	%VEC(4), -VEC_SIZE(%rdi,%rdx)
+	VMOVU	%VEC(5), -(VEC_SIZE * 2)(%rdi,%rdx)
+	VMOVU	%VEC(6), -(VEC_SIZE * 3)(%rdi,%rdx)
+	VMOVU	%VEC(7), -(VEC_SIZE * 4)(%rdi,%rdx)
+	VZEROUPPER
+	ret
+L(last_4x_vec):
+	/* Copy from 2 * VEC to 4 * VEC. */
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	VEC_SIZE(%rsi), %VEC(1)
+	VMOVU	-VEC_SIZE(%rsi,%rdx), %VEC(2)
+	VMOVU	-(VEC_SIZE * 2)(%rsi,%rdx), %VEC(3)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), VEC_SIZE(%rdi)
+	VMOVU	%VEC(2), -VEC_SIZE(%rdi,%rdx)
+	VMOVU	%VEC(3), -(VEC_SIZE * 2)(%rdi,%rdx)
+	VZEROUPPER
+	ret
+L(between_0_and_4x_vec):
+	/* Copy from 0 to 4 * VEC. */
+	cmpl	$(VEC_SIZE * 2), %edx
+	jae	L(last_4x_vec)
+	/* Copy from 0 to 2 * VEC. */
+	cmpl	$VEC_SIZE, %edx
+	jae	L(last_2x_vec)
+	/* Copy from 0 to VEC. */
+	VZEROUPPER
+	jmp	L(less_vec)
+L(more_8x_vec):
+	cmpq	%rsi, %rdi
+	ja	L(more_8x_vec_backward)
+
+	.p2align 4
+L(loop_8x_vec_forward):
+	/* Copy 8 * VEC a time forward.  */
+	VMOVU	(%rsi), %VEC(0)
+	VMOVU	VEC_SIZE(%rsi), %VEC(1)
+	VMOVU	(VEC_SIZE * 2)(%rsi), %VEC(2)
+	VMOVU	(VEC_SIZE * 3)(%rsi), %VEC(3)
+	VMOVU	(VEC_SIZE * 4)(%rsi), %VEC(4)
+	VMOVU	(VEC_SIZE * 5)(%rsi), %VEC(5)
+	VMOVU	(VEC_SIZE * 6)(%rsi), %VEC(6)
+	VMOVU	(VEC_SIZE * 7)(%rsi), %VEC(7)
+	VMOVU	%VEC(0), (%rdi)
+	VMOVU	%VEC(1), VEC_SIZE(%rdi)
+	VMOVU	%VEC(2), (VEC_SIZE * 2)(%rdi)
+	VMOVU	%VEC(3), (VEC_SIZE * 3)(%rdi)
+	VMOVU	%VEC(4), (VEC_SIZE * 4)(%rdi)
+	VMOVU	%VEC(5), (VEC_SIZE * 5)(%rdi)
+	VMOVU	%VEC(6), (VEC_SIZE * 6)(%rdi)
+	VMOVU	%VEC(7), (VEC_SIZE * 7)(%rdi)
+	addq	$(VEC_SIZE * 8), %rdi
+	addq	$(VEC_SIZE * 8), %rsi
+	subq	$(VEC_SIZE * 8), %rdx
+	cmpq	$(VEC_SIZE * 8), %rdx
+	je	L(between_4x_vec_and_8x_vec)
+	ja	L(loop_8x_vec_forward)
+	/* Less than 8 * VEC to copy.  */
+	cmpq	$(VEC_SIZE * 4), %rdx
+	jb	L(between_0_and_4x_vec)
+	jmp	L(between_4x_vec_and_8x_vec)
+
+	.p2align 4
+L(more_8x_vec_backward):
+	leaq	-VEC_SIZE(%rsi, %rdx), %rcx
+	leaq	-VEC_SIZE(%rdi, %rdx), %r9
+
+	.p2align 4
+L(loop_8x_vec_backward):
+	/* Copy 8 * VEC a time backward.  */
+	VMOVU	(%rcx), %VEC(0)
+	VMOVU	-VEC_SIZE(%rcx), %VEC(1)
+	VMOVU	-(VEC_SIZE * 2)(%rcx), %VEC(2)
+	VMOVU	-(VEC_SIZE * 3)(%rcx), %VEC(3)
+	VMOVU	-(VEC_SIZE * 4)(%rcx), %VEC(4)
+	VMOVU	-(VEC_SIZE * 5)(%rcx), %VEC(5)
+	VMOVU	-(VEC_SIZE * 6)(%rcx), %VEC(6)
+	VMOVU	-(VEC_SIZE * 7)(%rcx), %VEC(7)
+	VMOVU	%VEC(0), (%r9)
+	VMOVU	%VEC(1), -VEC_SIZE(%r9)
+	VMOVU	%VEC(2), -(VEC_SIZE * 2)(%r9)
+	VMOVU	%VEC(3), -(VEC_SIZE * 3)(%r9)
+	VMOVU	%VEC(4), -(VEC_SIZE * 4)(%r9)
+	VMOVU	%VEC(5), -(VEC_SIZE * 5)(%r9)
+	VMOVU	%VEC(6), -(VEC_SIZE * 6)(%r9)
+	VMOVU	%VEC(7), -(VEC_SIZE * 7)(%r9)
+	subq	$(VEC_SIZE * 8), %rcx
+	subq	$(VEC_SIZE * 8), %r9
+	subq	$(VEC_SIZE * 8), %rdx
+	cmpq	$(VEC_SIZE * 8), %rdx
+	je	L(between_4x_vec_and_8x_vec)
+	ja	L(loop_8x_vec_backward)
+	/* Less than 8 * VEC to copy.  */
+	cmpq	$(VEC_SIZE * 4), %rdx
+	jb	L(between_0_and_4x_vec)
+	jmp	L(between_4x_vec_and_8x_vec)
+END (MEMMOVE_SYMBOL (__memmove, unaligned_erms))
+
+# ifdef SHARED
+strong_alias (MEMMOVE_SYMBOL (__memmove, unaligned_erms),
+	      MEMMOVE_SYMBOL (__memcpy, unaligned_erms))
+strong_alias (MEMMOVE_SYMBOL (__memmove_chk, unaligned_erms),
+	      MEMMOVE_SYMBOL (__memcpy_chk, unaligned_erms))
+strong_alias (MEMMOVE_SYMBOL (__memmove, unaligned_2),
+	      MEMMOVE_SYMBOL (__memcpy, unaligned_2))
+strong_alias (MEMMOVE_SYMBOL (__memmove_chk, unaligned_2),
+	      MEMMOVE_SYMBOL (__memcpy_chk, unaligned_2))
+# endif
+
+#endif