Add Atom-optimized strchr and strrchr for x86-64

6 files changed, 861 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index 9dbb0cd..299f86b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-07-20  Liubov Dmitrieva  <liubov.dmitrieva@intel.com>
+
+	* sysdeps/x86_64/multiarch/Makefile (sysdep_routines): Add
+	strchr-sse2-no-bsf strrchr-sse2-no-bsf
+	* sysdeps/x86_64/multiarch/strchr.S: Update.
+	Check bit_slow_BSF bit.
+	* sysdeps/x86_64/multiarch/strrchr.S: Likewise.
+	* sysdeps/x86_64/multiarch/strchr-sse2-no-bsf.S: New file.
+	* sysdeps/x86_64/multiarch/strrchr-sse2-no-bsf.S: New file.
+
 2011-09-05  Ulrich Drepper  <drepper@gmail.com>
 
 	[BZ #13134]
diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index c959dd1..a5254dc 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -14,7 +14,8 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c strcmp-ssse3 strncmp-ssse3 \
 		   strcpy-sse2-unaligned strncpy-sse2-unaligned \
 		   stpcpy-sse2-unaligned stpncpy-sse2-unaligned \
 		   strcat-sse2-unaligned strncat-sse2-unaligned \
-		   strcat-ssse3 strncat-ssse3 strlen-sse2-pminub
+		   strcat-ssse3 strncat-ssse3 strlen-sse2-pminub \
+		   strrchr-sse2-no-bsf strchr-sse2-no-bsf
 ifeq (yes,$(config-cflags-sse4))
 sysdep_routines += strcspn-c strpbrk-c strspn-c strstr-c strcasestr-c varshift
 CFLAGS-varshift.c += -msse4
diff --git a/sysdeps/x86_64/multiarch/strchr-sse2-no-bsf.S b/sysdeps/x86_64/multiarch/strchr-sse2-no-bsf.S
new file mode 100644
index 0000000..e3f080c
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/strchr-sse2-no-bsf.S
@@ -0,0 +1,282 @@
+/* strchr with SSE2 without bsf
+   Copyright (C) 2011 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef  NOT_IN_libc
+
+# include <sysdep.h>
+# include "asm-syntax.h"
+
+	.text
+ENTRY (__strchr_sse2_no_bsf)
+	movd	%esi, %xmm1
+	movq	%rdi, %rcx
+	punpcklbw %xmm1, %xmm1
+	andq	$~15, %rdi
+	pxor	%xmm2, %xmm2
+	punpcklbw %xmm1, %xmm1
+	orl	$0xffffffff, %esi
+	movdqa	(%rdi), %xmm0
+	pshufd	$0, %xmm1, %xmm1
+	subq	%rdi, %rcx
+	movdqa	%xmm0, %xmm3
+	leaq	16(%rdi), %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pcmpeqb	%xmm2, %xmm3
+	shl	%cl, %esi
+	pmovmskb %xmm0, %eax
+	pmovmskb %xmm3, %edx
+	andl	%esi, %eax
+	andl	%esi, %edx
+	test	%eax, %eax
+	jnz	L(matches)
+	test	%edx, %edx
+	jnz	L(return_null)
+
+L(loop):
+	movdqa	(%rdi), %xmm0
+	leaq	16(%rdi), %rdi
+	movdqa	%xmm0, %xmm3
+	pcmpeqb	%xmm1, %xmm0
+	pcmpeqb	%xmm2, %xmm3
+	pmovmskb %xmm0, %eax
+	pmovmskb %xmm3, %edx
+	or	%eax, %edx
+	jz	L(loop)
+
+	pmovmskb %xmm3, %edx
+	test	%eax, %eax
+	jnz	L(matches)
+
+/* Return NULL.  */
+	.p2align 4
+L(return_null):
+	xor	%rax, %rax
+	ret
+
+L(matches):
+	/* There is a match.  First find where NULL is.  */
+	leaq	-16(%rdi), %rdi
+	test	%edx, %edx
+	jz	L(match_case1)
+
+	.p2align 4
+L(match_case2):
+	test	%al, %al
+	jz	L(match_high_case2)
+
+	mov	%al, %cl
+	and	$15, %cl
+	jnz	L(match_case2_4)
+
+	mov	%dl, %ch
+	and	$15, %ch
+	jnz	L(return_null)
+
+	test	$0x10, %al
+	jnz	L(Exit5)
+	test	$0x10, %dl
+	jnz	L(return_null)
+	test	$0x20, %al
+	jnz	L(Exit6)
+	test	$0x20, %dl
+	jnz	L(return_null)
+	test	$0x40, %al
+	jnz	L(Exit7)
+	test	$0x40, %dl
+	jnz	L(return_null)
+	lea	7(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_case2_4):
+	test	$0x01, %al
+	jnz	L(Exit1)
+	test	$0x01, %dl
+	jnz	L(return_null)
+	test	$0x02, %al
+	jnz	L(Exit2)
+	test	$0x02, %dl
+	jnz	L(return_null)
+	test	$0x04, %al
+	jnz	L(Exit3)
+	test	$0x04, %dl
+	jnz	L(return_null)
+	lea	3(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_high_case2):
+	test	%dl, %dl
+	jnz	L(return_null)
+
+	mov	%ah, %cl
+	and	$15, %cl
+	jnz	L(match_case2_12)
+
+	mov	%dh, %ch
+	and	$15, %ch
+	jnz	L(return_null)
+
+	test	$0x10, %ah
+	jnz	L(Exit13)
+	test	$0x10, %dh
+	jnz	L(return_null)
+	test	$0x20, %ah
+	jnz	L(Exit14)
+	test	$0x20, %dh
+	jnz	L(return_null)
+	test	$0x40, %ah
+	jnz	L(Exit15)
+	test	$0x40, %dh
+	jnz	L(return_null)
+	lea	15(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_case2_12):
+	test	$0x01, %ah
+	jnz	L(Exit9)
+	test	$0x01, %dh
+	jnz	L(return_null)
+	test	$0x02, %ah
+	jnz	L(Exit10)
+	test	$0x02, %dh
+	jnz	L(return_null)
+	test	$0x04, %ah
+	jnz	L(Exit11)
+	test	$0x04, %dh
+	jnz	L(return_null)
+	lea	11(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_case1):
+	test	%al, %al
+	jz	L(match_high_case1)
+
+	test	$0x01, %al
+	jnz	L(Exit1)
+	test	$0x02, %al
+	jnz	L(Exit2)
+	test	$0x04, %al
+	jnz	L(Exit3)
+	test	$0x08, %al
+	jnz	L(Exit4)
+	test	$0x10, %al
+	jnz	L(Exit5)
+	test	$0x20, %al
+	jnz	L(Exit6)
+	test	$0x40, %al
+	jnz	L(Exit7)
+	lea	7(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_high_case1):
+	test	$0x01, %ah
+	jnz	L(Exit9)
+	test	$0x02, %ah
+	jnz	L(Exit10)
+	test	$0x04, %ah
+	jnz	L(Exit11)
+	test	$0x08, %ah
+	jnz	L(Exit12)
+	test	$0x10, %ah
+	jnz	L(Exit13)
+	test	$0x20, %ah
+	jnz	L(Exit14)
+	test	$0x40, %ah
+	jnz	L(Exit15)
+	lea	15(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit1):
+	lea	(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit2):
+	lea	1(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit3):
+	lea	2(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit4):
+	lea	3(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit5):
+	lea	4(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit6):
+	lea	5(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit7):
+	lea	6(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit9):
+	lea	8(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit10):
+	lea	9(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit11):
+	lea	10(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit12):
+	lea	11(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit13):
+	lea	12(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit14):
+	lea	13(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit15):
+	lea	14(%rdi), %rax
+	ret
+
+END (__strchr_sse2_no_bsf)
+#endif
+
diff --git a/sysdeps/x86_64/multiarch/strchr.S b/sysdeps/x86_64/multiarch/strchr.S
index 71845a3..97a6057 100644
--- a/sysdeps/x86_64/multiarch/strchr.S
+++ b/sysdeps/x86_64/multiarch/strchr.S
@@ -33,7 +33,11 @@ ENTRY(strchr)
 	testl	$bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
 	jz	2f
 	leaq	__strchr_sse42(%rip), %rax
-2:	ret
+	ret
+2:	testl	$bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip)
+	jz	3f
+	leaq    __strchr_sse2_no_bsf(%rip), %rax
+3:	ret
 END(strchr)
 
 
diff --git a/sysdeps/x86_64/multiarch/strrchr-sse2-no-bsf.S b/sysdeps/x86_64/multiarch/strrchr-sse2-no-bsf.S
new file mode 100644
index 0000000..bd002a6
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/strrchr-sse2-no-bsf.S
@@ -0,0 +1,557 @@
+/* strrchr with SSE2 without bsf and bsr
+   Copyright (C) 2011 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#if defined SHARED && !defined NOT_IN_libc
+
+# include <sysdep.h>
+# include "asm-syntax.h"
+
+	.text
+ENTRY (__strrchr_sse2_no_bsf)
+
+	movd	%rsi, %xmm1
+	pxor	%xmm2, %xmm2
+	mov	%rdi, %rcx
+	punpcklbw %xmm1, %xmm1
+	punpcklbw %xmm1, %xmm1
+	/* ECX has OFFSET. */
+	and	$63, %rcx
+	cmp	$48, %rcx
+	pshufd	$0, %xmm1, %xmm1
+	ja	L(crosscache)
+
+/* unaligned string. */
+	movdqu	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	pcmpeqb	%xmm1, %xmm0
+	/* Find where NULL is.  */
+	pmovmskb %xmm2, %rcx
+	/* Check if there is a match.  */
+	pmovmskb %xmm0, %rax
+	add	$16, %rdi
+
+	test	%rax, %rax
+	jnz	L(unaligned_match1)
+
+	test	%rcx, %rcx
+	jnz	L(return_null)
+
+	and	$-16, %rdi
+	xor	%r8, %r8
+	jmp	L(loop)
+
+	.p2align 4
+L(unaligned_match1):
+	test	%rcx, %rcx
+	jnz	L(prolog_find_zero_1)
+
+	mov	%rax, %r8
+	mov	%rdi, %rsi
+	and	$-16, %rdi
+	jmp	L(loop)
+
+	.p2align 4
+L(crosscache):
+/* Hancle unaligned string.  */
+	and	$15, %rcx
+	and	$-16, %rdi
+	pxor	%xmm3, %xmm3
+	movdqa	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm3
+	pcmpeqb	%xmm1, %xmm0
+	/* Find where NULL is.  */
+	pmovmskb %xmm3, %rdx
+	/* Check if there is a match.  */
+	pmovmskb %xmm0, %rax
+	/* Remove the leading bytes.  */
+	shr	%cl, %rdx
+	shr	%cl, %rax
+	add	$16, %rdi
+
+	test	%rax, %rax
+	jnz	L(unaligned_match)
+
+	test	%rdx, %rdx
+	jnz	L(return_null)
+
+	xor	%r8, %r8
+	jmp	L(loop)
+
+	.p2align 4
+L(unaligned_match):
+	test	%rdx, %rdx
+	jnz	L(prolog_find_zero)
+
+	mov	%rax, %r8
+	lea	(%rdi, %rcx), %rsi
+
+/* Loop start on aligned string.  */
+	.p2align 4
+L(loop):
+	movdqa	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %rcx
+	pmovmskb %xmm0, %rax
+	or	%rax, %rcx
+	jnz	L(matches)
+
+	movdqa	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %rcx
+	pmovmskb %xmm0, %rax
+	or	%rax, %rcx
+	jnz	L(matches)
+
+	movdqa	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %rcx
+	pmovmskb %xmm0, %rax
+	or	%rax, %rcx
+	jnz	L(matches)
+
+	movdqa	(%rdi), %xmm0
+	pcmpeqb	%xmm0, %xmm2
+	add	$16, %rdi
+	pcmpeqb	%xmm1, %xmm0
+	pmovmskb %xmm2, %rcx
+	pmovmskb %xmm0, %rax
+	or	%rax, %rcx
+	jz	L(loop)
+
+L(matches):
+	test	%rax, %rax
+	jnz	L(match)
+L(return_value):
+	test	%r8, %r8
+	jz	L(return_null)
+	mov	%r8, %rax
+	mov	%rsi, %rdi
+	jmp	L(match_exit)
+
+	.p2align 4
+L(match):
+	pmovmskb %xmm2, %rcx
+	test	%rcx, %rcx
+	jnz	L(find_zero)
+	mov	%rax, %r8
+	mov	%rdi, %rsi
+	jmp	L(loop)
+
+	.p2align 4
+L(find_zero):
+	test	%cl, %cl
+	jz	L(find_zero_high)
+	mov	%cl, %dl
+	and	$15, %dl
+	jz	L(find_zero_8)
+	test	$0x01, %cl
+	jnz	L(FindZeroExit1)
+	test	$0x02, %cl
+	jnz	L(FindZeroExit2)
+	test	$0x04, %cl
+	jnz	L(FindZeroExit3)
+	and	$1 << 4 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(find_zero_8):
+	test	$0x10, %cl
+	jnz	L(FindZeroExit5)
+	test	$0x20, %cl
+	jnz	L(FindZeroExit6)
+	test	$0x40, %cl
+	jnz	L(FindZeroExit7)
+	and	$1 << 8 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(find_zero_high):
+	mov	%ch, %dh
+	and	$15, %dh
+	jz	L(find_zero_high_8)
+	test	$0x01, %ch
+	jnz	L(FindZeroExit9)
+	test	$0x02, %ch
+	jnz	L(FindZeroExit10)
+	test	$0x04, %ch
+	jnz	L(FindZeroExit11)
+	and	$1 << 12 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(find_zero_high_8):
+	test	$0x10, %ch
+	jnz	L(FindZeroExit13)
+	test	$0x20, %ch
+	jnz	L(FindZeroExit14)
+	test	$0x40, %ch
+	jnz	L(FindZeroExit15)
+	and	$1 << 16 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit1):
+	and	$1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit2):
+	and	$1 << 2 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit3):
+	and	$1 << 3 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit5):
+	and	$1 << 5 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit6):
+	and	$1 << 6 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit7):
+	and	$1 << 7 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit9):
+	and	$1 << 9 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit10):
+	and	$1 << 10 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit11):
+	and	$1 << 11 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit13):
+	and	$1 << 13 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit14):
+	and	$1 << 14 - 1, %rax
+	jz	L(return_value)
+	jmp	L(match_exit)
+
+	.p2align 4
+L(FindZeroExit15):
+	and	$1 << 15 - 1, %rax
+	jz	L(return_value)
+
+	.p2align 4
+L(match_exit):
+	test	%ah, %ah
+	jnz	L(match_exit_high)
+	mov	%al, %dl
+	and	$15 << 4, %dl
+	jnz	L(match_exit_8)
+	test	$0x08, %al
+	jnz	L(Exit4)
+	test	$0x04, %al
+	jnz	L(Exit3)
+	test	$0x02, %al
+	jnz	L(Exit2)
+	lea	-16(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_exit_8):
+	test	$0x80, %al
+	jnz	L(Exit8)
+	test	$0x40, %al
+	jnz	L(Exit7)
+	test	$0x20, %al
+	jnz	L(Exit6)
+	lea	-12(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_exit_high):
+	mov	%ah, %dh
+	and	$15 << 4, %dh
+	jnz	L(match_exit_high_8)
+	test	$0x08, %ah
+	jnz	L(Exit12)
+	test	$0x04, %ah
+	jnz	L(Exit11)
+	test	$0x02, %ah
+	jnz	L(Exit10)
+	lea	-8(%rdi), %rax
+	ret
+
+	.p2align 4
+L(match_exit_high_8):
+	test	$0x80, %ah
+	jnz	L(Exit16)
+	test	$0x40, %ah
+	jnz	L(Exit15)
+	test	$0x20, %ah
+	jnz	L(Exit14)
+	lea	-4(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit2):
+	lea	-15(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit3):
+	lea	-14(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit4):
+	lea	-13(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit6):
+	lea	-11(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit7):
+	lea	-10(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit8):
+	lea	-9(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit10):
+	lea	-7(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit11):
+	lea	-6(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit12):
+	lea	-5(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit14):
+	lea	-3(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit15):
+	lea	-2(%rdi), %rax
+	ret
+
+	.p2align 4
+L(Exit16):
+	lea	-1(%rdi), %rax
+	ret
+
+/* Return NULL.  */
+	.p2align 4
+L(return_null):
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(prolog_find_zero):
+	add	%rcx, %rdi
+	mov     %rdx, %rcx
+L(prolog_find_zero_1):
+	test	%cl, %cl
+	jz	L(prolog_find_zero_high)
+	mov	%cl, %dl
+	and	$15, %dl
+	jz	L(prolog_find_zero_8)
+	test	$0x01, %cl
+	jnz	L(PrologFindZeroExit1)
+	test	$0x02, %cl
+	jnz	L(PrologFindZeroExit2)
+	test	$0x04, %cl
+	jnz	L(PrologFindZeroExit3)
+	and	$1 << 4 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(prolog_find_zero_8):
+	test	$0x10, %cl
+	jnz	L(PrologFindZeroExit5)
+	test	$0x20, %cl
+	jnz	L(PrologFindZeroExit6)
+	test	$0x40, %cl
+	jnz	L(PrologFindZeroExit7)
+	and	$1 << 8 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(prolog_find_zero_high):
+	mov	%ch, %dh
+	and	$15, %dh
+	jz	L(prolog_find_zero_high_8)
+	test	$0x01, %ch
+	jnz	L(PrologFindZeroExit9)
+	test	$0x02, %ch
+	jnz	L(PrologFindZeroExit10)
+	test	$0x04, %ch
+	jnz	L(PrologFindZeroExit11)
+	and	$1 << 12 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(prolog_find_zero_high_8):
+	test	$0x10, %ch
+	jnz	L(PrologFindZeroExit13)
+	test	$0x20, %ch
+	jnz	L(PrologFindZeroExit14)
+	test	$0x40, %ch
+	jnz	L(PrologFindZeroExit15)
+	and	$1 << 16 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit1):
+	and	$1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit2):
+	and	$1 << 2 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit3):
+	and	$1 << 3 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit5):
+	and	$1 << 5 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit6):
+	and	$1 << 6 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit7):
+	and	$1 << 7 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit9):
+	and	$1 << 9 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit10):
+	and	$1 << 10 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit11):
+	and	$1 << 11 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit13):
+	and	$1 << 13 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit14):
+	and	$1 << 14 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+	.p2align 4
+L(PrologFindZeroExit15):
+	and	$1 << 15 - 1, %rax
+	jnz	L(match_exit)
+	xor	%rax, %rax
+	ret
+
+END (__strrchr_sse2_no_bsf)
+#endif
+
diff --git a/sysdeps/x86_64/multiarch/strrchr.S b/sysdeps/x86_64/multiarch/strrchr.S
index 0d17fdb..4a746c7 100644
--- a/sysdeps/x86_64/multiarch/strrchr.S
+++ b/sysdeps/x86_64/multiarch/strrchr.S
@@ -35,7 +35,11 @@ ENTRY(strrchr)
 	testl	$bit_SSE4_2, __cpu_features+CPUID_OFFSET+index_SSE4_2(%rip)
 	jz	2f
 	leaq	__strrchr_sse42(%rip), %rax
-2:	ret
+	ret
+2:	testl	$bit_Slow_BSF, __cpu_features+FEATURE_OFFSET+index_Slow_BSF(%rip)
+	jz	3f
+	leaq    __strrchr_sse2_no_bsf(%rip), %rax
+3:	ret
 END(strrchr)
 
 /*