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[PATCH] powerpc: strstr optimization


This patch optimizes strstr function for power >= 7 systems.  Performance
gain is obtained using doubleword aligned memory access and usage of cmpb
instruction for quicker comparison.  The average improvement of this
optimization is ~40%.

2015-04-17  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>

	* sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strstr().
	* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c: Likewise.
	* sysdeps/powerpc/powerpc64/power7/strstr.S: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c: New File.
	* sysdeps/powerpc/powerpc64/multiarch/strstr.c: New File.
---
 sysdeps/powerpc/powerpc64/multiarch/Makefile       |   2 +-
 .../powerpc/powerpc64/multiarch/ifunc-impl-list.c  |   8 +
 .../powerpc/powerpc64/multiarch/strstr-power7.S    |  44 ++
 sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c |  29 ++
 sysdeps/powerpc/powerpc64/multiarch/strstr.c       |  34 ++
 sysdeps/powerpc/powerpc64/power7/strstr.S          | 500 +++++++++++++++++++++
 6 files changed, 616 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strstr.c
 create mode 100644 sysdeps/powerpc/powerpc64/power7/strstr.S

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 17265bd..3b0e3a0 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -19,7 +19,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   strcmp-power8 strcmp-power7 strcmp-ppc64 \
 		   strcat-power8 strcat-power7 strcat-ppc64 \
 		   memmove-power7 memmove-ppc64 wordcopy-ppc64 bcopy-ppc64 \
-		   strncpy-power8
+		   strncpy-power8 strstr-power7 strstr-ppc64
 
 CFLAGS-strncase-power7.c += -mcpu=power7 -funroll-loops
 CFLAGS-strncase_l-power7.c += -mcpu=power7 -funroll-loops
diff --git a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
index f5fdea5..9d808e0 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -322,5 +322,13 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, strcat, 1,
 			     __strcat_ppc))
 
+  /* Support sysdeps/powerpc/powerpc64/multiarch/strstr.c.  */
+  IFUNC_IMPL (i, name, strstr,
+	      IFUNC_IMPL_ADD (array, i, strstr,
+			      hwcap & PPC_FEATURE_HAS_VSX,
+			      __strstr_power7)
+	      IFUNC_IMPL_ADD (array, i, strstr, 1,
+			      __strstr_ppc))
+
   return i;
 }
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S
new file mode 100644
index 0000000..68b93b0
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr-power7.S
@@ -0,0 +1,44 @@
+/* Optimized strstr implementation for POWER7.
+   Copyright (C) 2015-2016 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/>.  */
+
+#include <sysdep.h>
+
+#undef EALIGN
+#define EALIGN(name, alignt, words)				\
+  .section ".text";						\
+  ENTRY_2(__strstr_power7)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strstr_power7):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strstr_power7)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strstr_power7)					\
+  END_2(__strstr_power7)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#define STRLEN __strlen_power7
+#define STRNLEN __strnlen_power7
+#define STRCHR __strchr_power7
+
+#include <sysdeps/powerpc/powerpc64/power7/strstr.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c
new file mode 100644
index 0000000..2ca62c4
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr-ppc64.c
@@ -0,0 +1,29 @@
+/* Copyright (C) 2015-2016 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/>.  */
+
+#include <string.h>
+
+#define STRSTR __strstr_ppc
+#if IS_IN (libc) && defined(SHARED)
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name) \
+  __hidden_ver1(__strstr_ppc, __GI_strstr, __strstr_ppc);
+#endif
+
+extern __typeof (strstr) __strstr_ppc attribute_hidden;
+
+#include <string/strstr.c>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strstr.c b/sysdeps/powerpc/powerpc64/multiarch/strstr.c
new file mode 100644
index 0000000..7efc4b0
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strstr.c
@@ -0,0 +1,34 @@
+/* Multiple versions of strstr. PowerPC64 version.
+   Copyright (C) 2015-2016 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/>.  */
+
+/* Define multiple versions only for definition in libc.  */
+#if IS_IN (libc)
+# include <string.h>
+# include <shlib-compat.h>
+# include "init-arch.h"
+
+extern __typeof (strstr) __strstr_ppc attribute_hidden;
+extern __typeof (strstr) __strstr_power7 attribute_hidden;
+
+/* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
+   ifunc symbol properly.  */
+libc_ifunc (strstr,
+            (hwcap & PPC_FEATURE_HAS_VSX)
+            ? __strstr_power7
+            : __strstr_ppc);
+#endif
diff --git a/sysdeps/powerpc/powerpc64/power7/strstr.S b/sysdeps/powerpc/powerpc64/power7/strstr.S
new file mode 100644
index 0000000..e895d36
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power7/strstr.S
@@ -0,0 +1,500 @@
+/* Optimized strstr implementation for PowerPC64/POWER7.
+   Copyright (C) 2015-2016 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/>.  */
+
+#include <sysdep.h>
+
+/* char * [r3] strstr (char *s [r3], char * pat[r4])  */
+
+/*
+ * The performance gain is obtained using aligned memory access, load doubleword
+ * and usage of cmpb instruction for quicker comparison.
+ */
+
+#ifndef STRLEN
+/* For builds with no IFUNC support, local calls should be made to internal
+   GLIBC symbol (created by libc_hidden_builtin_def).  */
+# ifdef SHARED
+#  define STRLEN   __GI_strlen
+# else
+#  define STRLEN   strlen
+# endif
+#endif
+
+#ifndef STRNLEN
+/* For builds with no IFUNC support, local calls should be made to internal
+   GLIBC symbol (created by libc_hidden_builtin_def).  */
+# ifdef SHARED
+#  define STRNLEN   __GI_strnlen
+# else
+#  define STRNLEN   strnlen
+# endif
+#endif
+
+#ifndef STRCHR
+# ifdef SHARED
+#  define STRCHR   __GI_strchr
+# else
+#  define STRCHR   strchr
+# endif
+#endif
+
+#define	FRAMESIZE	(FRAME_MIN_SIZE+32)
+	.machine  power7
+EALIGN (strstr, 4, 0)
+	CALL_MCOUNT 2
+	mflr	r0			/* load link register LR to r0 */
+	std	r20, -8(r1)		/* save callers register , r20 */
+	std	r19, -16(r1)		/* save callers register , r19 */
+	std	r18, -24(r1)		/* save callers register , r18 */
+	std	r0, 16(r1)		/* store the link register  */
+	stdu	r1, -FRAMESIZE(r1)	/* create the stack frame  */
+
+	dcbt	0, r3
+	dcbt	0, r4
+
+	and	r0, r3, r4
+	cmpdi	cr7, r0, 0
+	beq	cr7, L(retnull)
+
+	mr	r18, r3
+	mr	r19, r4
+	mr	r3, r4
+	bl	STRLEN
+	nop
+
+	cmpdi	cr7, r3, 0	/* if search str is null */
+	beq	cr7, L(ret_r3)
+	mr	r20, r3
+	mr	r4, r3
+	mr	r3, r18
+	bl	STRNLEN
+	nop
+
+	cmpd	cr7, r3, r20 	/* if len(r3) < len(r4) */
+	blt	cr7, L(retnull)
+	mr	r3, r18
+	lbz	r4, 0(r19)
+	bl	STRCHR
+	nop
+
+	mr	r11, r3
+	/* if first char of search str is not present */
+	cmpdi	cr7, r3, 0
+	ble	cr7, L(end)
+
+	rldicl	r8, r3, 0, 52	/* page cross check */
+	cmpldi	cr7, r8, 4096-16
+	bgt	cr7, L(bytebybyte)
+
+	rldicl	r8, r19, 0, 52
+	cmpldi	cr7, r8, 4096-16
+	bgt	cr7, L(bytebybyte)
+
+	/* if len(r4) < 8 handle in a different way */
+	/* Shift position based on null and use cmpb */
+	cmpdi	cr7, r20, 8
+	blt	cr7, L(lessthan8)
+
+	/*  len(r4) >= 8 reaches here */
+	mr	r8, r3		/* save r3 for future use */
+L(begin):
+	mr	r3, r8
+	mr	r4, r19		/* restore r4 */
+	li	r0, 0
+
+L(begin2):
+	rlwinm	r10, r19, 3, 26, 28	/* calculate padding in bits */
+	clrrdi	r4, r4, 3	/* Make r4 aligned to 8 */
+	ld	r6, 0(r4)
+	addi	r4, r4, 8
+	cmpdi	cr7, r10, 0	/* check if its already aligned? */
+	beq	cr7, L(begin1)
+#ifdef __LITTLE_ENDIAN__
+	srd	r6, r6, r10	/* Discard unwanted bits */
+#else
+	sld	r6, r6, r10
+#endif
+	ld	r9, 0(r4)
+	subfic	r10, r10, 64
+#ifdef __LITTLE_ENDIAN__
+	sld	r9, r9, r10	/*  Discard unwanted bits */
+#else
+	srd	r9, r9, r10
+#endif
+	or	r6, r6, r9	/* Form complete search str */
+L(begin1):
+	rlwinm	r10, r3, 3, 26, 28
+	clrrdi	r3, r3, 3
+	ld	r5, 0(r3)
+	cmpb	r9, r0, r6	/* check if input has null */
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(return3)
+	cmpb	r9, r0, r5	/* check if input has null */
+#ifdef __LITTLE_ENDIAN__
+	srd	r9, r9, r10
+#else
+	sld	r9, r9, r10
+#endif
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(return2)
+
+	cmpdi	cr7, r10, 0
+	beq	cr7, L(loop2)
+	ldu	r7, 8(r3)
+	mr	r12, r10
+	addi	r12, r12, -8
+	subfic	r11, r12, 64
+	srdi	r9, r11, 3
+	addi	r9, r9, -1
+	mtctr	r9
+	b	L(nextbyte1)
+
+L(loop2):
+	li	r9, 8
+	li	r12, -8		/* shift values	*/
+	li	r11, 72		/* shift values */
+	ldu	r7, 8(r3) 	/* load next dw */
+	mtctr	r9
+L(nextbyte1):
+	addi	r12, r12, 8	/* shift one byte and compare */
+	addi	r11, r11, -8
+#ifdef __LITTLE_ENDIAN__
+	srd	r9, r5, r12	/* rotate based on mask */
+	sld	r10, r7, r11
+#else
+	sld	r9, r5, r12
+	srd	r10, r7, r11
+#endif
+	/* Form single dw from few bytes on first load and second load */
+	or	r10, r9, r10
+	/* Check for null in the formed dw */
+	cmpb	r9, r0, r10
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(retnull)
+	/* cmpb search str and input str */
+	cmpb	r9, r10, r6
+	cmpdi	cr7, r9, -1
+	beq	cr7, L(match)
+	bdnz	L(nextbyte1)
+	/* Check if input has null before next load */
+	cmpb	r9, r0, r7
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(retnull)
+	mr	r5, r7
+	/* Proceed to next load */
+	b	L(loop2)
+
+	.align	4
+L(match):
+	/* There is a match of 8 bytes, check next bytes */
+	cmpdi	cr7, r20, 8
+	beq	cr7, L(return)
+	/* Update next starting point r8 */
+	srdi	r9, r11, 3
+	subf	r9, r9, r3
+	mr	r8, r9
+
+L(secondmatch):
+	mr	r5, r7
+	rlwinm	r10, r19, 3, 26, 28	/* calculate padding in bits */
+	ld	r6, 0(r4)
+	addi	r4, r4, 8
+	cmpdi	cr7, r10, 0	/* check if its already aligned? */
+	beq	cr7, L(proceed3)
+#ifdef __LITTLE_ENDIAN__
+	srd	r6, r6, r10	/* Discard unwanted bits */
+	cmpb	r9, r0, r6
+	sld	r9, r9, r10
+#else
+	sld	r6, r6, r10
+	cmpb	r9, r0, r6
+	srd	r9, r9, r10
+#endif
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(proceed3)
+	ld	r9, 0(r4)
+	subfic	r10, r10, 64
+#ifdef __LITTLE_ENDIAN__
+	sld	r9, r9, r10	/*  Discard unwanted bits */
+#else
+	srd	r9, r9, r10
+#endif
+	or	r6, r6, r9	/* Form complete search str */
+
+L(proceed3):
+	li	r7, 0
+	addi	r3, r3, 8
+	cmpb	r9, r0, r5
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(proceed4)
+	ld	r7, 0(r3)
+L(proceed4):
+#ifdef __LITTLE_ENDIAN__
+	srd	r9, r5, r12
+	sld	r10, r7, r11
+#else
+	sld	r9, r5, r12
+	srd	r10, r7, r11
+#endif
+	/* Form single dw with few bytes from first and second load */
+	or	r10, r9, r10
+	cmpb	r9, r0, r6
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(return4)
+	/* Check for null in the formed dw */
+	cmpb	r9, r0, r10
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(retnull)
+	/* If the next 8 bytes dont match, start search again */
+	cmpb	r9, r10, r6
+	cmpdi	cr7, r9, -1
+	bne	cr7, L(reset)
+	/* If the next 8 bytes match, load and compare next 8 */
+	b	L(secondmatch)
+
+	.align	4
+L(reset):
+	/* start the search again */
+	addi	r8, r8, 1
+	b	L(begin)
+
+	.align	4
+L(loadnext):
+	/* Update r3 and proceed */
+	addi	r3, r3, 8
+	b	L(begin2)
+
+	.align	4
+L(return2):
+	mr	r3, r8
+	b	L(end)
+
+	.align	4
+L(return3):
+	/* Count leading zeros and compare partial dw*/
+#ifdef __LITTLE_ENDIAN__
+	addi	r7, r9, -1
+	andc	r7, r7, r9
+	popcntd	r7, r7
+	subfic	r7, r7, 64
+	sld	r10, r5, r7
+	sld	r6, r6, r7
+#else
+	cntlzd	r7, r9
+	subfic	r7, r7, 64
+	srd	r10, r5, r7
+	srd	r6, r6, r7
+#endif
+	cmpb	r9, r10, r6
+	cmpdi	cr7, r9, -1
+	addi	r8, r8, 1
+	/* start search again if there is no match */
+	bne	cr7, L(begin)
+	/* if the words match, update return values */
+	subfic	r7, r7, 64
+	srdi	r7, r7, 3
+	add	r3, r3, r7
+	subf	r3, r20, r3
+	b	L(end)
+
+	.align	4
+L(return4):
+	/* Count leading zeros and compare partial dw*/
+#ifdef __LITTLE_ENDIAN__
+	addi	r7, r9, -1
+	andc	r7, r7, r9
+	popcntd	r7, r7
+	subfic	r7, r7, 64
+	sld	r10, r10, r7
+	sld	r6, r6, r7
+#else
+	cntlzd	r7, r9
+	subfic	r7, r7, 64
+	srd	r10, r10, r7
+	srd	r6, r6, r7
+#endif
+	cmpb	r9, r10, r6
+	cmpdi	cr7, r9, -1
+	addi	r8, r8, 1
+	bne	cr7, L(begin)
+	subfic	r7, r7, 64
+	srdi	r11, r11, 3
+	subf	r3, r11, r3
+	srdi	r7, r7, 3
+	add	r3, r3, r7
+	subf	r3, r20, r3
+	b	L(end)
+
+	/* handle less than 8 search string */
+	.align	4
+L(lessthan8):
+	mr	r4, r19
+	li	r0, 0
+
+	rlwinm	r10, r4, 3, 26, 28	/* calculate padding in bits */
+	srdi	r8, r10, 3	/* padding in bytes */
+	clrrdi	r4, r4, 3	/* Make r4 aligned to 8 */
+	ld	r6, 0(r4)
+	cmpdi	cr7, r10, 0	/* check if its already aligned? */
+	beq	cr7, L(proceed2)
+#ifdef __LITTLE_ENDIAN__
+	srd	r6, r6, r10	/* Discard unwanted bits */
+#else
+	sld	r6, r6, r10
+#endif
+	subfic	r8, r8, 8
+	cmpd	cr7, r8, r20	/* Next load needed? */
+	bge	cr7, L(proceed2)
+	ld	r7, 8(r4)
+	subfic	r10, r10, 64
+#ifdef __LITTLE_ENDIAN__
+	sld	r7, r7, r10	/*  Discard unwanted bits */
+#else
+	srd	r7, r7, r10
+#endif
+	or	r6, r6, r7	/* Form complete search str */
+L(proceed2):
+	rlwinm	r10, r3, 3, 26, 28
+	clrrdi	r3, r3, 3	/* Make r3 aligned */
+	ld	r5, 0(r3)
+	sldi	r8, r20, 3
+	subfic	r8, r8, 64
+#ifdef __LITTLE_ENDIAN__
+	sld	r6, r6, r8
+	cmpb	r9, r0, r5
+	srd	r9, r9, r10
+#else
+	srd	r6, r6, r8
+	cmpb	r9, r0, r5
+	sld	r9, r9, r10
+#endif
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(noload)
+	cmpdi	cr7, r10, 0
+	beq	cr7, L(continue)
+	ldu	r7, 8(r3)
+	mr	r12, r10
+	addi	r12, r12, -8
+	subfic	r11, r12, 64
+	srdi	r9, r11, 3
+	addi	r9, r9, -1
+	mtctr	r9
+	b	L(nextbyte)
+L(continue):
+	ldu	r7, 8(r3)
+L(continue1):
+	li	r9, 8
+	li	r12, -8		/* shift values	*/
+	li	r11, 72		/* shift values */
+	mtctr	r9
+L(nextbyte):
+	addi	r12, r12, 8	/* mask for rotation */
+	addi	r11, r11, -8
+#ifdef __LITTLE_ENDIAN__
+	srd	r9, r5, r12
+	sld	r10, r7, r11
+	or	r10, r9, r10
+	sld	r10, r10, r8
+	cmpb	r9, r0, r10
+	srd	r9, r9, r8
+#else
+	sld	r9, r5, r12
+	srd	r10, r7, r11
+	or	r10, r9, r10
+	srd	r10, r10, r8
+	cmpb	r9, r0, r10
+	sld	r9, r9, r8
+#endif
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(retnull)
+	cmpb	r9, r10, r6
+	cmpdi	cr7, r9, -1
+	beq	cr7, L(return)
+	bdnz	L(nextbyte)
+	mr	r5, r7
+	/* Check null in loaded dw */
+	cmpb	r9, r0, r7
+	cmpdi	cr7, r9, 0
+	bne	cr7, L(noload)
+	b	L(continue)
+
+	.align	4
+L(noload):
+	/* Reached null in r3, so skip next load */
+	addi	r3, r3, 8
+	li 	r7, 0
+	b	L(continue1)
+
+	.align	4
+L(return):
+	/* Update return values */
+	srdi	r9, r11, 3
+	subf	r3, r9, r3
+	b	L(end)
+
+	/* handling byte by byte */
+	.align	4
+L(bytebybyte):
+	mr	r8, r3
+	addi	r8, r8, -1
+L(loop1):
+	addi	r8, r8, 1
+	mr	r3, r8
+	mr	r4, r19
+	lbz	r6, 0(r4)
+	cmpdi	cr7, r6, 0
+	beq	cr7, L(updater3)
+L(loop):
+	lbz	r5, 0(r3)
+	cmpdi	cr7, r5, 0
+	beq	cr7, L(retnull)
+	cmpld	cr7, r6, r5
+	bne	cr7, L(loop1)
+	addi	r3, r3, 1
+	addi	r4, r4, 1
+	lbz	r6, 0(r4)
+	cmpdi	cr7, r6, 0
+	beq	cr7, L(updater3)
+	b	L(loop)
+
+	/* handling return values */
+	.align	4
+L(updater3):
+	subf	r3, r20, r3	/* reduce len of r4 from r3 */
+	b	L(end)
+
+	.align	4
+L(ret_r3):
+	mr	r3, r18		/* return r3 */
+	b	L(end)
+
+	.align	4
+L(retnull):
+	li	r3, 0		/* return NULL */
+
+	.align	4
+L(end):
+	addi	r1, r1, FRAMESIZE	/* restore stack pointer  */
+	ld	r0, 16(r1)	/* read the saved link register  */
+	ld	r18, -24(r1)	/* restore callers save register, r18  */
+	ld	r19, -16(r1)	/* restore callers save register, r19  */
+	ld	r20, -8(r1)	/* restore callers save register, r20  */
+	mtlr	r0		/* branch to link register  */
+	blr
+END (strstr)
+libc_hidden_builtin_def (strstr)
-- 
1.8.3.1


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