From a3ba4670970effea5e4b26977ec6f95751b63577 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sun, 21 May 2017 09:22:44 -0700
Subject: [PATCH 2/8] x86-64: Optimize wmemset with SSE2/AVX2/AVX512

The difference between memset and wmemset is byte vs int.  Add stubs
to SSE2/AVX2/AVX512 memset for wmemset with updated constant and size:

SSE2 wmemset:
	shl    $0x2,%rdx
	movd   %esi,%xmm0
	mov    %rdi,%rax
	pshufd $0x0,%xmm0,%xmm0
	jmp	entry_from_wmemset

SSE2 memset:
	movd   %esi,%xmm0
	mov    %rdi,%rax
	punpcklbw %xmm0,%xmm0
	punpcklwd %xmm0,%xmm0
	pshufd $0x0,%xmm0,%xmm0
entry_from_wmemset:

Since the ERMS versions of wmemset requires "rep stosl" instead of
"rep stosb", only the vector store stubs of SSE2/AVX2/AVX512 wmemset
are added.  The SSE2 wmemset is about 3X faster and the AVX2 wmemset
is about 6X faster on Haswell.

	* include/wchar.h (__wmemset_chk): New.
	* sysdeps/x86_64/memset.S (VDUP_TO_VEC0_AND_SET_RETURN): Renamed
	to MEMSET_VDUP_TO_VEC0_AND_SET_RETURN.
	(WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
	(WMEMSET_CHK_SYMBOL): Likewise.
	(WMEMSET_SYMBOL): Likewise.
	(__wmemset): Add hidden definition.
	(wmemset): Add weak hidden definition.
	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
	wmemset_chk-nonshared.
	* sysdeps/x86_64/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Add __wmemset_sse2_unaligned,
	__wmemset_avx2_unaligned, __wmemset_avx512_unaligned,
	__wmemset_chk_sse2_unaligned, __wmemset_chk_avx2_unaligned
	and __wmemset_chk_avx512_unaligned.
	* sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
	(VDUP_TO_VEC0_AND_SET_RETURN): Renamed to ...
	(MEMSET_VDUP_TO_VEC0_AND_SET_RETURN): This.
	(WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
	(WMEMSET_SYMBOL): Likewise.
	* sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
	(VDUP_TO_VEC0_AND_SET_RETURN): Renamed to ...
	(MEMSET_VDUP_TO_VEC0_AND_SET_RETURN): This.
	(WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN): New.
	(WMEMSET_SYMBOL): Likewise.
	* sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S: Updated.
	(WMEMSET_CHK_SYMBOL): New.
	(WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned)): Likewise.
	(WMEMSET_SYMBOL (__wmemset, unaligned)): Likewise.
	* sysdeps/x86_64/multiarch/memset.S (WMEMSET_SYMBOL): New.
	(libc_hidden_builtin_def): Also define __GI_wmemset and
	__GI___wmemset.
	(weak_alias): New.
	* sysdeps/x86_64/multiarch/wmemset.c: New file.
	* sysdeps/x86_64/multiarch/wmemset.h: Likewise.
	* sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S: Likewise.
	* sysdeps/x86_64/multiarch/wmemset_chk.c: Likewise.
	* sysdeps/x86_64/wmemset.c: Likewise.
	* sysdeps/x86_64/wmemset_chk.c: Likewise.
---
 include/wchar.h                                    |  3 ++
 sysdeps/x86_64/memset.S                            | 18 +++++++++-
 sysdeps/x86_64/multiarch/Makefile                  |  4 +++
 sysdeps/x86_64/multiarch/ifunc-impl-list.c         | 22 ++++++++++++
 .../x86_64/multiarch/memset-avx2-unaligned-erms.S  |  8 ++++-
 .../multiarch/memset-avx512-unaligned-erms.S       |  9 ++++-
 .../x86_64/multiarch/memset-vec-unaligned-erms.S   | 24 +++++++++++--
 sysdeps/x86_64/multiarch/memset.S                  | 13 +++++--
 sysdeps/x86_64/multiarch/wmemset.c                 | 33 +++++++++++++++++
 sysdeps/x86_64/multiarch/wmemset.h                 | 42 ++++++++++++++++++++++
 sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S   | 21 +++++++++++
 sysdeps/x86_64/multiarch/wmemset_chk.c             | 31 ++++++++++++++++
 sysdeps/x86_64/wmemset.S                           |  1 +
 sysdeps/x86_64/wmemset_chk.S                       | 33 +++++++++++++++++
 14 files changed, 253 insertions(+), 9 deletions(-)
 create mode 100644 sysdeps/x86_64/multiarch/wmemset.c
 create mode 100644 sysdeps/x86_64/multiarch/wmemset.h
 create mode 100644 sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S
 create mode 100644 sysdeps/x86_64/multiarch/wmemset_chk.c
 create mode 100644 sysdeps/x86_64/wmemset.S
 create mode 100644 sysdeps/x86_64/wmemset_chk.S

diff --git a/include/wchar.h b/include/wchar.h
index e2579a1..a773d56 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -157,6 +157,9 @@ extern wchar_t *__wmemmove (wchar_t *__s1, const wchar_t *__s2,
 extern wchar_t *__wcschrnul (const wchar_t *__s, wchar_t __wc)
      __attribute_pure__;
 
+extern wchar_t *__wmemset_chk (wchar_t *__s, wchar_t __c, size_t __n,
+			       size_t __ns) __THROW;
+
 extern int __vfwscanf (__FILE *__restrict __s,
 		       const wchar_t *__restrict __format,
 		       __gnuc_va_list __arg)
diff --git a/sysdeps/x86_64/memset.S b/sysdeps/x86_64/memset.S
index 69ed509..4127878 100644
--- a/sysdeps/x86_64/memset.S
+++ b/sysdeps/x86_64/memset.S
@@ -26,13 +26,18 @@
 #define VMOVU		movdqu
 #define VMOVA		movdqa
 
-#define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+#define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
   movd d, %xmm0; \
   movq r, %rax; \
   punpcklbw %xmm0, %xmm0; \
   punpcklwd %xmm0, %xmm0; \
   pshufd $0, %xmm0, %xmm0
 
+#define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+  movd d, %xmm0; \
+  movq r, %rax; \
+  pshufd $0, %xmm0, %xmm0
+
 #define SECTION(p)		p
 
 #ifndef MEMSET_SYMBOL
@@ -40,10 +45,21 @@
 # define MEMSET_SYMBOL(p,s)	memset
 #endif
 
+#ifndef WMEMSET_SYMBOL
+# define WMEMSET_CHK_SYMBOL(p,s) p
+# define WMEMSET_SYMBOL(p,s)	__wmemset
+#endif
+
 #include "multiarch/memset-vec-unaligned-erms.S"
 
 libc_hidden_builtin_def (memset)
 
+#if IS_IN (libc)
+libc_hidden_def (__wmemset)
+weak_alias (__wmemset, wmemset)
+libc_hidden_weak (wmemset)
+#endif
+
 #if defined SHARED && IS_IN (libc) && !defined USE_MULTIARCH
 strong_alias (__memset_chk, __memset_zero_constant_len_parameter)
 	.section .gnu.warning.__memset_zero_constant_len_parameter
diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 3736f54..65a545b 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -32,3 +32,7 @@ endif
 ifeq ($(subdir),wcsmbs)
 sysdep_routines += wmemcmp-sse4 wmemcmp-ssse3 wmemcmp-c wcscpy-ssse3 wcscpy-c
 endif
+
+ifeq ($(subdir),debug)
+sysdep_routines += wmemset_chk-nonshared
+endif
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 06d9a9d..a91d2f9 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -300,6 +300,17 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			      __wmemcmp_ssse3)
 	      IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
 
+  /* Support sysdeps/x86_64/multiarch/wmemset.S.  */
+  IFUNC_IMPL (i, name, wmemset,
+	      IFUNC_IMPL_ADD (array, i, wmemset, 1,
+			      __wmemset_sse2_unaligned)
+	      IFUNC_IMPL_ADD (array, i, wmemset,
+			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      __wmemset_avx2_unaligned)
+	      IFUNC_IMPL_ADD (array, i, wmemset,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __wmemset_avx512_unaligned))
+
 #ifdef SHARED
   /* Support sysdeps/x86_64/multiarch/memcpy_chk.S.  */
   IFUNC_IMPL (i, name, __memcpy_chk,
@@ -417,6 +428,17 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, strncmp, HAS_CPU_FEATURE (SSSE3),
 			      __strncmp_ssse3)
 	      IFUNC_IMPL_ADD (array, i, strncmp, 1, __strncmp_sse2))
+
+  /* Support sysdeps/x86_64/multiarch/wmemset_chk.S.  */
+  IFUNC_IMPL (i, name, __wmemset_chk,
+	      IFUNC_IMPL_ADD (array, i, __wmemset_chk, 1,
+			      __wmemset_chk_sse2_unaligned)
+	      IFUNC_IMPL_ADD (array, i, __wmemset_chk,
+			      HAS_ARCH_FEATURE (AVX2_Usable),
+			      __wmemset_chk_avx2_unaligned)
+	      IFUNC_IMPL_ADD (array, i, __wmemset_chk,
+			      HAS_ARCH_FEATURE (AVX512F_Usable),
+			      __wmemset_chk_avx512_unaligned))
 #endif
 
   return i;
diff --git a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
index 79975e0..7ab3d89 100644
--- a/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-avx2-unaligned-erms.S
@@ -4,13 +4,19 @@
 # define VMOVU		vmovdqu
 # define VMOVA		vmovdqa
 
-# define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
   vmovd d, %xmm0; \
   movq r, %rax; \
   vpbroadcastb %xmm0, %ymm0
 
+# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+  vmovd d, %xmm0; \
+  movq r, %rax; \
+  vpbroadcastd %xmm0, %ymm0
+
 # define SECTION(p)		p##.avx
 # define MEMSET_SYMBOL(p,s)	p##_avx2_##s
+# define WMEMSET_SYMBOL(p,s)	p##_avx2_##s
 
 # include "memset-vec-unaligned-erms.S"
 #endif
diff --git a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
index a5ec349..0783979 100644
--- a/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-avx512-unaligned-erms.S
@@ -4,14 +4,21 @@
 # define VMOVU		vmovdqu64
 # define VMOVA		vmovdqa64
 
-# define VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+# define MEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
   vmovd d, %xmm0; \
   movq r, %rax; \
   vpbroadcastb %xmm0, %xmm0; \
   vpbroadcastq %xmm0, %zmm0
 
+# define WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN(d, r) \
+  vmovd d, %xmm0; \
+  movq r, %rax; \
+  vpbroadcastd %xmm0, %xmm0; \
+  vpbroadcastq %xmm0, %zmm0
+
 # define SECTION(p)		p##.avx512
 # define MEMSET_SYMBOL(p,s)	p##_avx512_##s
+# define WMEMSET_SYMBOL(p,s)	p##_avx512_##s
 
 # include "memset-vec-unaligned-erms.S"
 #endif
diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
index 704eed9..2eb9e37 100644
--- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
+++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
@@ -30,6 +30,10 @@
 # define MEMSET_CHK_SYMBOL(p,s)		MEMSET_SYMBOL(p, s)
 #endif
 
+#ifndef WMEMSET_CHK_SYMBOL
+# define WMEMSET_CHK_SYMBOL(p,s)	WMEMSET_SYMBOL(p, s)
+#endif
+
 #ifndef VZEROUPPER
 # if VEC_SIZE > 16
 #  define VZEROUPPER			vzeroupper
@@ -79,6 +83,21 @@ END (__bzero)
 weak_alias (__bzero, bzero)
 #endif
 
+#if IS_IN (libc)
+# if defined SHARED
+ENTRY_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
+	cmpq	%rdx, %rcx
+	jb	HIDDEN_JUMPTARGET (__chk_fail)
+END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
+# endif
+
+ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
+	shlq	$2, %rdx
+	WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
+	jmp	L(entry_from_bzero)
+END (WMEMSET_SYMBOL (__wmemset, unaligned))
+#endif
+
 #if defined SHARED && IS_IN (libc)
 ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
 	cmpq	%rdx, %rcx
@@ -87,8 +106,7 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
 #endif
 
 ENTRY (MEMSET_SYMBOL (__memset, unaligned))
-L(memset_entry):
-	VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
+	MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
 L(entry_from_bzero):
 	cmpq	$VEC_SIZE, %rdx
 	jb	L(less_vec)
@@ -132,7 +150,7 @@ END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
 # endif
 
 ENTRY (MEMSET_SYMBOL (__memset, unaligned_erms))
-	VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
+	MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
 	cmpq	$VEC_SIZE, %rdx
 	jb	L(less_vec)
 	cmpq	$(VEC_SIZE * 2), %rdx
diff --git a/sysdeps/x86_64/multiarch/memset.S b/sysdeps/x86_64/multiarch/memset.S
index 9d33118..11f2737 100644
--- a/sysdeps/x86_64/multiarch/memset.S
+++ b/sysdeps/x86_64/multiarch/memset.S
@@ -58,16 +58,23 @@ END(memset)
 
 #if IS_IN (libc)
 # define MEMSET_SYMBOL(p,s)	p##_sse2_##s
+# define WMEMSET_SYMBOL(p,s)	p##_sse2_##s
 
 # ifdef SHARED
-# undef libc_hidden_builtin_def
+#  undef libc_hidden_builtin_def
 /* It doesn't make sense to send libc-internal memset calls through a PLT.
    The speedup we get from using SSE2 instructions is likely eaten away
    by the indirect call in the PLT.  */
-# define libc_hidden_builtin_def(name) \
-	.globl __GI_memset; __GI_memset = __memset_sse2_unaligned
+#  define libc_hidden_builtin_def(name) \
+	.globl __GI_memset; __GI_memset = __memset_sse2_unaligned; \
+	.globl __GI_wmemset; __GI_wmemset = __wmemset_sse2_unaligned; \
+	.globl __GI___wmemset; __GI___wmemset = __wmemset_sse2_unaligned
 # endif
 
+# undef weak_alias
+# define weak_alias(original, alias) \
+	.weak bzero; bzero = __bzero
+
 # undef strong_alias
 # define strong_alias(original, alias)
 #endif
diff --git a/sysdeps/x86_64/multiarch/wmemset.c b/sysdeps/x86_64/multiarch/wmemset.c
new file mode 100644
index 0000000..61626a9
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/wmemset.c
@@ -0,0 +1,33 @@
+/* Multiple versions of wmemset.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017 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/>.  */
+
+/* Define multiple versions only for the definition in libc. */
+#if IS_IN (libc)
+# define wmemset __redirect_wmemset
+# define __wmemset __redirect___wmemset
+# include <wchar.h>
+# undef wmemset
+# undef __wmemset
+
+# define SYMBOL_NAME wmemset
+# include "wmemset.h"
+
+libc_ifunc_redirected (__redirect_wmemset, __wmemset, IFUNC_SELECTOR ());
+weak_alias (__wmemset, wmemset)
+#endif
diff --git a/sysdeps/x86_64/multiarch/wmemset.h b/sysdeps/x86_64/multiarch/wmemset.h
new file mode 100644
index 0000000..d761985
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/wmemset.h
@@ -0,0 +1,42 @@
+/* Common definition for wmemset/wmemset_chk ifunc selections.
+   Copyright (C) 2017 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/>.  */
+
+#include <init-arch.h>
+
+extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2_unaligned) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_unaligned) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE (avx512_unaligned) attribute_hidden;
+
+static inline void *
+IFUNC_SELECTOR (void)
+{
+  const struct cpu_features* cpu_features = __get_cpu_features ();
+
+  if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER)
+      && CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
+      && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
+    {
+      if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable)
+	  && !CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_AVX512))
+	return OPTIMIZE (avx512_unaligned);
+      else
+	return OPTIMIZE (avx2_unaligned);
+    }
+
+  return OPTIMIZE (sse2_unaligned);
+}
diff --git a/sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S b/sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S
new file mode 100644
index 0000000..0a537fe
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/wmemset_chk-nonshared.S
@@ -0,0 +1,21 @@
+/* Non-shared version of wmemset_chk for x86-64.
+   Copyright (C) 2017 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) && !defined SHARED
+# include "../wmemset_chk.S"
+#endif
diff --git a/sysdeps/x86_64/multiarch/wmemset_chk.c b/sysdeps/x86_64/multiarch/wmemset_chk.c
new file mode 100644
index 0000000..2c039a5
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/wmemset_chk.c
@@ -0,0 +1,31 @@
+/* Multiple versions of wmemset_chk.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017 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/>.  */
+
+/* Define multiple versions only for the definition in libc.so. */
+#if IS_IN (libc) && defined SHARED
+# define __wmemset_chk __redirect_wmemset_chk
+# include <wchar.h>
+# undef __wmemset_chk
+
+# define SYMBOL_NAME wmemset_chk
+# include "wmemset.h"
+
+libc_ifunc_redirected (__redirect_wmemset_chk, __wmemset_chk,
+		       IFUNC_SELECTOR ());
+#endif
diff --git a/sysdeps/x86_64/wmemset.S b/sysdeps/x86_64/wmemset.S
new file mode 100644
index 0000000..f96d567
--- /dev/null
+++ b/sysdeps/x86_64/wmemset.S
@@ -0,0 +1 @@
+/* Implemented in memset.S.  */
diff --git a/sysdeps/x86_64/wmemset_chk.S b/sysdeps/x86_64/wmemset_chk.S
new file mode 100644
index 0000000..64c2774
--- /dev/null
+++ b/sysdeps/x86_64/wmemset_chk.S
@@ -0,0 +1,33 @@
+/* Checking wmemset for x86-64.
+   Copyright (C) 2004-2017 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/>.  */
+
+#include <sysdep.h>
+#include "asm-syntax.h"
+
+#ifndef SHARED
+	/* For libc.so this is defined in wmemset.S.
+	   For libc.a, this is a separate source to avoid
+	   wmemset bringing in __chk_fail and all routines
+	   it calls.  */
+        .text
+ENTRY (__wmemset_chk)
+	cmpq	%rdx, %rcx
+	jb	__chk_fail
+	jmp	wmemset
+END (__wmemset_chk)
+#endif
-- 
2.9.4
