diff mbox

This is optimized strcmp for Power7

Message ID 1401945190-13296-1-git-send-email-vidya@linux.vnet.ibm.com
State New
Headers show

Commit Message

vidya@linux.vnet.ibm.com June 5, 2014, 5:13 a.m. UTC 
From: Vidya Ranganathan <vidya@linux.vnet.ibm.com>

Optimization is achieved on 8 byte aligned strings with double word
comparison using cmpb instruction. On unaligned strings loop unrolling
is applied for Power7 gain.

Signed-off-by: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
---
 sysdeps/powerpc/powerpc64/multiarch/Makefile       |   2 +-
 .../powerpc/powerpc64/multiarch/ifunc-impl-list.c  |   7 +
 .../powerpc/powerpc64/multiarch/strcmp-power7.S    |  40 +++++
 sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S |  43 +++++
 sysdeps/powerpc/powerpc64/multiarch/strcmp.c       |  31 ++++
 sysdeps/powerpc/powerpc64/power7/strcmp.S          | 195 +++++++++++++++++++++
 6 files changed, 317 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
 create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp.c
 create mode 100644 sysdeps/powerpc/powerpc64/power7/strcmp.S

Comments

Adhemerval Zanella June 10, 2014, 2:13 p.m. UTC | #1 
Hi Vidya,

Path looks good, however you forgot to add a ChangeLog.  Also one typo below.
Please send the CL entry that will push upstream.

On 05-06-2014 02:13, vidya@linux.vnet.ibm.com wrote:

> From: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
>
> Optimization is achieved on 8 byte aligned strings with double word
> comparison using cmpb instruction. On unaligned strings loop unrolling
> is applied for Power7 gain.
>
> Signed-off-by: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
> ---
>  sysdeps/powerpc/powerpc64/multiarch/Makefile       |   2 +-
>  .../powerpc/powerpc64/multiarch/ifunc-impl-list.c  |   7 +
>  .../powerpc/powerpc64/multiarch/strcmp-power7.S    |  40 +++++
>  sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S |  43 +++++
>  sysdeps/powerpc/powerpc64/multiarch/strcmp.c       |  31 ++++
>  sysdeps/powerpc/powerpc64/power7/strcmp.S          | 195 +++++++++++++++++++++
>  6 files changed, 317 insertions(+), 1 deletion(-)
>  create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>  create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>  create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>  create mode 100644 sysdeps/powerpc/powerpc64/power7/strcmp.S
>
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> index 35020a7..05744e9 100644
> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> @@ -17,7 +17,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
>  		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
>  		   strspn-power7 strspn-ppc64 strcspn-power7 strcspn-ppc64 \
>  		   strpbrk-power7 strpbrk-ppc64 strncpy-power7 strncpy-ppc64 \
> -		   stpncpy-power7 stpncpy-ppc64
> +		   stpncpy-power7 stpncpy-ppc64 strcmp-power7 strcmp-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 d8578fb..b3933a5 100644
> --- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
> @@ -294,5 +294,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>  	      IFUNC_IMPL_ADD (array, i, stpncpy, 1,
>  			     __stpncpy_ppc))
>
> +  /* Support sysdeps/powerpc/powerpc64/multiarch/strcmp.c.  */
> +  IFUNC_IMPL (i, name, strcmp,
> +	      IFUNC_IMPL_ADD (array, i, strcmp,
> +			      hwcap & PPC_FEATURE_HAS_VSX,
> +			      __strcmp_power7)
> +	      IFUNC_IMPL_ADD (array, i, strcmp, 1,
> +			     __strcmp_ppc))
>    return i;
>  }
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
> new file mode 100644
> index 0000000..790ce8d
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
> @@ -0,0 +1,40 @@
> +/* Optimized strcmp implementation for POWER7.
> +   Copyright (C) 2014 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(__strcmp_power7)					\
> +  .align ALIGNARG(alignt);					\
> +  EALIGN_W_##words;						\
> +  BODY_LABEL(__strcmp_power7):					\
> +  cfi_startproc;						\
> +  LOCALENTRY(__strcmp_power7)
> +
> +#undef END
> +#define END(name)						\
> +  cfi_endproc;							\
> +  TRACEBACK(__strcmp_power7)					\
> +  END_2(__strcmp_power7)
> +
> +#undef libc_hidden_builtin_def
> +#define libc_hidden_builtin_def(name)
> +
> +#include <sysdeps/powerpc/powerpc64/power7/strcmp.S>
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
> new file mode 100644
> index 0000000..93d1277
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
> @@ -0,0 +1,43 @@
> +/* Default strcmp implementation for PowerPC64.
> +   Copyright (C) 2014 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>
> +
> +#if defined SHARED && !defined NOT_IN_libc
> +# undef EALIGN
> +# define EALIGN(name, alignt, words)				\
> +  .section ".text";						\
> +  ENTRY_2(__strcmp_ppc)						\
> +  .align ALIGNARG(alignt);					\
> +  EALIGN_W_##words;						\
> +  BODY_LABEL(__strcmp_ppc):					\
> +  cfi_startproc;						\
> +  LOCALENTRY(__strcmp_ppc)
> +
> +# undef END
> +# define END(name)						\
> +  cfi_endproc;							\
> +  TRACEBACK(__strcmp_ppc)					\
> +  END_2(__strcmp_ppc)
> +
> +# undef libc_hidden_builtin_def
> +# define libc_hidden_builtin_def(name)				\
> +    .globl __GI_strcmp; __GI_strcmp = __strcmp_ppc
> +#endif
> +
> +#include <sysdeps/powerpc/powerpc64/strcmp.S>
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
> new file mode 100644
> index 0000000..2013301
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
> @@ -0,0 +1,31 @@
> +/* Multiple versions of strcmp. PowerPC64 version.
> +   Copyright (C) 2014 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 defined SHARED && !defined NOT_IN_libc
> +# include <string.h>
> +# include <shlib-compat.h>
> +# include "init-arch.h"
> +
> +extern __typeof (strcmp) __strcmp_ppc attribute_hidden;
> +extern __typeof (strcmp) __strcmp_power7 attribute_hidden;
> +
> +libc_ifunc (strcmp,
> +            (hwcap & PPC_FEATURE_HAS_VSX)
> +            ? __strcmp_power7
> +            : __strcmp_ppc);
> +#endif
> diff --git a/sysdeps/powerpc/powerpc64/power7/strcmp.S b/sysdeps/powerpc/powerpc64/power7/strcmp.S
> new file mode 100644
> index 0000000..f16a9d8
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/power7/strcmp.S
> @@ -0,0 +1,195 @@
> +/* Optimized strcmp implementation for Power7 using 'cmpb' instruction
> +   Copyright (C) 2014 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/>.  */
> +
> +/* The optimization is achieved here through cmpb instruction.
> +   8byte aligned strings are processed with double word comparision
s/comparision/comparison
> +   and unaligned strings are handled effectively with loop unrolling
> +   technique  */
> +
> +#include <sysdep.h>
> +
> +/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4])  */
> +
> +EALIGN (strcmp, 4, 0)
> +	CALL_MCOUNT 2
> +
> +	or r9, r3, r4
> +	rldicl. r10, r9, 0, 61	/* are s1 and s2 8 byte aligned..?  */
> +	bne cr0, L(process_unaligned_bytes)
> +
> +/* process input parameters on double word aligned boundary  */
> +	ld r9, 0(r4)		/* load s2 at offset=0  */
> +	li r10, 0		/* load mask=0  */
> +	cmpb r10, r9, r10	/* compare bytes at s2 with mask  */
> +	cmpdi cr7, r10, 0	/* is NULL found ..? is end of string HIT  */
> +	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
> +
> +	ld r10, 0(r3)		/* load s1 at offset=0  */
> +	li r8, 0		/* load mask=0  */
> +	cmpb r8, r10, r8	/* compare bytes at s1 with mask  */
> +	cmpdi cr7, r8, 0	/* is NULL found ..? is end of string HIT  */
> +	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
> +
> +/*s1 and s2 does not contain NULL now , so compare all 8 bytes in a GO  */
> +	cmpb r9, r10, r9	/* compare s1 and s2  */
> +	cmpdi cr7, r9, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
> +	bne cr7, L(process_unaligned_bytes)	/* s1,s2 mismatch found  */
> +
> +	addi r5, r3, 8		/* save next offset of s2  */
> +	addi r11, r4, 8		/* save next offset of s1  */
> +	ld r8, 8(r4)		/* load s2 at offset=8  */
> +	li r9, 0		/* load mask=0  */
> +	cmpb r9, r8, r9		/* compare bytes at s2 with mask  */
> +	cmpdi cr7, r9, 0	/* NULL found ..?  */
> +	bne cr7, L(processBytes)/* update input and process bytes one by one  */
> +
> +	mr r9, r4		/* save s2  */
> +	li r10, 0		/* load mask=0  */
> +
> +	ld r7, 8(r3)		/* load s1 at offset=8  */
> +	cmpb r6, r7, r10	/* compare bytes at s1 with mask  */
> +	cmpdi cr7, r6, 0	/* is NULL found  */
> +	bne cr7, L(processBytes)/* mismatch, so process one by one  */
> +
> +L(unrollDword):
> +	cmpb r8, r7, r8		/* compare s1 and s2  */
> +	cmpdi cr7, r8, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
> +	bne cr7, L(processBytes)/* mismatch with s1 and s2  */
> +
> +	addi r5, r3, 16		/* save offset=16 of s1  */
> +	addi r4, r9, 16		/* save offset=16 of s2  */
> +	ld r8, 16(r9)		/* load s2 at offset=16  */
> +	cmpb r7, r8, r10	/* compare bytes at s2 with mask  */
> +	cmpdi cr7, r7, 0	/* NULL found  ..?  */
> +	bne cr7, L(update2processBytes)
> +
> +	ld r7, 16(r3)		/* load s1 at offset=16  */
> +	cmpb r6, r7, r10	/* check s1 for end of string  */
> +	cmpdi cr7, r6, 0	/* end of s1 ?,then handle byte by byte  */
> +	bne 7,L(update2processBytes)
> +
> +	cmpb r8, r7, r8		/* compare s1 and s2 double words  */
> +	cmpdi cr7, r8, -1	/* compare results with 0xFFFFFFFFFFFFFFFF  */
> +	bne cr7,L(update2processBytes)
> +
> +	addi r5, r3, 24		/* update s1 to offset=24  */
> +	addi r4, r9, 24		/* update s2 to offset=24  */
> +
> +	ld r8, 24(r9)		/* load s2  */
> +	cmpb r7, r8, r10	/* compare s2 for NULL  */
> +	cmpdi cr7, r7, 0	/* verify if s2 is ending now  */
> +	bne cr7,L(update2processBytes)
> +
> +	ld r7, 24(r3)		/* load s1 at offset=24  */
> +	cmpb r6, r7, r10	/* verify for NULL  */
> +	cmpdi cr7, r6, 0	/* is NULL found  */
> +	bne cr7, L(update2processBytes)
> +
> +	cmpb r8, r7, r8		/* compare s1 and s2  */
> +	cmpdi cr7, r8, -1	/* are s1 and s2 same ..?  */
> +	bne cr7, L(update2processBytes)
> +
> +	addi r7, r9, 32		/* update s2 to next double word  */
> +	addi r3, r3, 32		/* update s1 to next double word  */
> +
> +	ld r8, 32(r9)		/* load s2  */
> +	mr r4, r7		/* save s2  */
> +	cmpb r6, r8, r10	/* compare s2 with NULL  */
> +	cmpdi cr7, r6, 0	/* end of s2 ..? */
> +	bne cr7, L(process_unaligned_bytes)
> +
> +	ld r6, 0(r3)		/* load and compare s1 for NULL  */
> +	cmpb r5, r6, r10
> +	cmpdi cr7, r5, 0
> +	bne cr7, L(process_unaligned_bytes)
> +
> +	cmpb r8, r6, r8		/* compare s1 and s2  */
> +	cmpdi cr7, r8, -1
> +	bne cr7, L(process_unaligned_bytes)
> +
> +	addi r5, r3, 8		/* increment s1 and d2 here  */
> +	addi r11, r9, 40
> +
> +	ld r8, 40(r9)		/* process s2 now  */
> +	cmpb r9, r8, r10
> +	cmpdi cr7, r9, 0
> +	bne cr7, L(processBytes)
> +
> +	mr r9, r7
> +	ld r7, 8(r3)		/* process s1 now  */
> +	cmpb r6, r7, r10
> +	cmpdi cr7, r6, 0
> +	beq cr7, L(unrollDword)	/* unroll to compare s1 and s2  */
> +
> +L(processBytes):
> +	mr r4, r11		/* update input params  */
> +	mr r3, r5
> +
> +	.p2align 4
> +L(process_unaligned_bytes):
> +	lbz r9, 0(r3)		/* load byte from s1  */
> +	lbz r10, 0(r4)		/* load byte from s2  */
> +	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
> +	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
> +	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
> +	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
> +
> +	lbz r9, 1(r3)		/* load next byte from s1  */
> +	lbz r10, 1(r4)		/* load next byte from s2  */
> +	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
> +	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
> +	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
> +	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
> +
> +	lbz r9, 2(r3)		/* unroll 3rd byte here  */
> +	lbz r10, 2(r4)
> +	cmpdi cr7, r9, 0
> +	beq cr7, L(diffOfNULL)
> +	cmplw cr7, r9, r10
> +	bne 7, L(ComputeDiff)
> +
> +	lbz r9, 3(r3)		/* unroll 4th byte now  */
> +	lbz r10, 3(r4)
> +	addi r3, r3, 4		/* increment s1 by unroll factor  */
> +	cmpdi cr7, r9, 0
> +	cmplw cr6, 9, r10
> +	beq cr7, L(diffOfNULL)
> +	addi r4, r4, 4		/* increment s2 by unroll factor  */
> +	beq cr6, L(process_unaligned_bytes)	/* unroll byte processing  */
> +
> +	.p2align 4
> +L(ComputeDiff):
> +	extsw r9, r9
> +	subf r10, r10, r9	/* compute s1 - s2  */
> +	extsw r3, r10
> +	blr			/* return  */
> +
> +	.p2align 4
> +L(diffOfNULL):
> +	li r9, 0
> +	subf r10, r10, r9	/* compute s1 - s2  */
> +	extsw r3, r10		/* sign extend result  */
> +	blr			/* return  */
> +
> +	.p2align 4
> +L(update2processBytes):
> +	mr r3, r5		/* update and proceed  */
> +	b L(process_unaligned_bytes)
> +
> +END (strcmp)
> +libc_hidden_builtin_def (strcmp)
vidya@linux.vnet.ibm.com June 10, 2014, 4:06 p.m. UTC | #2 
Hi Adhemerval , thanks for the review. Yeah , i seem to have forgotten 
the ChangeLog.
Here it is:
-----------------------------------------------------------------------------------------------------------
2014-06-05  Vidya Ranganathan  <vidya@linux.vnet.ibm.com>

         * sysdeps/powerpc/powerpc64/power7/strcmp.S: New file: 
Optimization.
         * sysdeps/powerpc/powerpc64/multiarch/strcmp.c: New file:
         multiarch strcmp for PPC64.
         * sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S: New file
         * sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S: New file
         * sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strcmp
         multiarch optimizations.
         * sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c:
         (__libc_ifunc_impl_list): Likewise.

-----------------------------------------------------------------------------------------------------------

On Tuesday 10 June 2014 07:43 PM, Adhemerval Zanella wrote:
> Hi Vidya,
>
> Path looks good, however you forgot to add a ChangeLog.  Also one typo below.
> Please send the CL entry that will push upstream.
>
> On 05-06-2014 02:13, vidya@linux.vnet.ibm.com wrote:
>
>> From: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
>>
>> Optimization is achieved on 8 byte aligned strings with double word
>> comparison using cmpb instruction. On unaligned strings loop unrolling
>> is applied for Power7 gain.
>>
>> Signed-off-by: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
>> ---
>>   sysdeps/powerpc/powerpc64/multiarch/Makefile       |   2 +-
>>   .../powerpc/powerpc64/multiarch/ifunc-impl-list.c  |   7 +
>>   .../powerpc/powerpc64/multiarch/strcmp-power7.S    |  40 +++++
>>   sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S |  43 +++++
>>   sysdeps/powerpc/powerpc64/multiarch/strcmp.c       |  31 ++++
>>   sysdeps/powerpc/powerpc64/power7/strcmp.S          | 195 +++++++++++++++++++++
>>   6 files changed, 317 insertions(+), 1 deletion(-)
>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>>   create mode 100644 sysdeps/powerpc/powerpc64/power7/strcmp.S
>>
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>> index 35020a7..05744e9 100644
>> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>> @@ -17,7 +17,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
>>   		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
>>   		   strspn-power7 strspn-ppc64 strcspn-power7 strcspn-ppc64 \
>>   		   strpbrk-power7 strpbrk-ppc64 strncpy-power7 strncpy-ppc64 \
>> -		   stpncpy-power7 stpncpy-ppc64
>> +		   stpncpy-power7 stpncpy-ppc64 strcmp-power7 strcmp-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 d8578fb..b3933a5 100644
>> --- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>> @@ -294,5 +294,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>>   	      IFUNC_IMPL_ADD (array, i, stpncpy, 1,
>>   			     __stpncpy_ppc))
>>
>> +  /* Support sysdeps/powerpc/powerpc64/multiarch/strcmp.c.  */
>> +  IFUNC_IMPL (i, name, strcmp,
>> +	      IFUNC_IMPL_ADD (array, i, strcmp,
>> +			      hwcap & PPC_FEATURE_HAS_VSX,
>> +			      __strcmp_power7)
>> +	      IFUNC_IMPL_ADD (array, i, strcmp, 1,
>> +			     __strcmp_ppc))
>>     return i;
>>   }
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>> new file mode 100644
>> index 0000000..790ce8d
>> --- /dev/null
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>> @@ -0,0 +1,40 @@
>> +/* Optimized strcmp implementation for POWER7.
>> +   Copyright (C) 2014 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(__strcmp_power7)					\
>> +  .align ALIGNARG(alignt);					\
>> +  EALIGN_W_##words;						\
>> +  BODY_LABEL(__strcmp_power7):					\
>> +  cfi_startproc;						\
>> +  LOCALENTRY(__strcmp_power7)
>> +
>> +#undef END
>> +#define END(name)						\
>> +  cfi_endproc;							\
>> +  TRACEBACK(__strcmp_power7)					\
>> +  END_2(__strcmp_power7)
>> +
>> +#undef libc_hidden_builtin_def
>> +#define libc_hidden_builtin_def(name)
>> +
>> +#include <sysdeps/powerpc/powerpc64/power7/strcmp.S>
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>> new file mode 100644
>> index 0000000..93d1277
>> --- /dev/null
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>> @@ -0,0 +1,43 @@
>> +/* Default strcmp implementation for PowerPC64.
>> +   Copyright (C) 2014 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>
>> +
>> +#if defined SHARED && !defined NOT_IN_libc
>> +# undef EALIGN
>> +# define EALIGN(name, alignt, words)				\
>> +  .section ".text";						\
>> +  ENTRY_2(__strcmp_ppc)						\
>> +  .align ALIGNARG(alignt);					\
>> +  EALIGN_W_##words;						\
>> +  BODY_LABEL(__strcmp_ppc):					\
>> +  cfi_startproc;						\
>> +  LOCALENTRY(__strcmp_ppc)
>> +
>> +# undef END
>> +# define END(name)						\
>> +  cfi_endproc;							\
>> +  TRACEBACK(__strcmp_ppc)					\
>> +  END_2(__strcmp_ppc)
>> +
>> +# undef libc_hidden_builtin_def
>> +# define libc_hidden_builtin_def(name)				\
>> +    .globl __GI_strcmp; __GI_strcmp = __strcmp_ppc
>> +#endif
>> +
>> +#include <sysdeps/powerpc/powerpc64/strcmp.S>
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>> new file mode 100644
>> index 0000000..2013301
>> --- /dev/null
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>> @@ -0,0 +1,31 @@
>> +/* Multiple versions of strcmp. PowerPC64 version.
>> +   Copyright (C) 2014 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 defined SHARED && !defined NOT_IN_libc
>> +# include <string.h>
>> +# include <shlib-compat.h>
>> +# include "init-arch.h"
>> +
>> +extern __typeof (strcmp) __strcmp_ppc attribute_hidden;
>> +extern __typeof (strcmp) __strcmp_power7 attribute_hidden;
>> +
>> +libc_ifunc (strcmp,
>> +            (hwcap & PPC_FEATURE_HAS_VSX)
>> +            ? __strcmp_power7
>> +            : __strcmp_ppc);
>> +#endif
>> diff --git a/sysdeps/powerpc/powerpc64/power7/strcmp.S b/sysdeps/powerpc/powerpc64/power7/strcmp.S
>> new file mode 100644
>> index 0000000..f16a9d8
>> --- /dev/null
>> +++ b/sysdeps/powerpc/powerpc64/power7/strcmp.S
>> @@ -0,0 +1,195 @@
>> +/* Optimized strcmp implementation for Power7 using 'cmpb' instruction
>> +   Copyright (C) 2014 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/>.  */
>> +
>> +/* The optimization is achieved here through cmpb instruction.
>> +   8byte aligned strings are processed with double word comparision
> s/comparision/comparison
>> +   and unaligned strings are handled effectively with loop unrolling
>> +   technique  */
>> +
>> +#include <sysdep.h>
>> +
>> +/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4])  */
>> +
>> +EALIGN (strcmp, 4, 0)
>> +	CALL_MCOUNT 2
>> +
>> +	or r9, r3, r4
>> +	rldicl. r10, r9, 0, 61	/* are s1 and s2 8 byte aligned..?  */
>> +	bne cr0, L(process_unaligned_bytes)
>> +
>> +/* process input parameters on double word aligned boundary  */
>> +	ld r9, 0(r4)		/* load s2 at offset=0  */
>> +	li r10, 0		/* load mask=0  */
>> +	cmpb r10, r9, r10	/* compare bytes at s2 with mask  */
>> +	cmpdi cr7, r10, 0	/* is NULL found ..? is end of string HIT  */
>> +	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
>> +
>> +	ld r10, 0(r3)		/* load s1 at offset=0  */
>> +	li r8, 0		/* load mask=0  */
>> +	cmpb r8, r10, r8	/* compare bytes at s1 with mask  */
>> +	cmpdi cr7, r8, 0	/* is NULL found ..? is end of string HIT  */
>> +	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
>> +
>> +/*s1 and s2 does not contain NULL now , so compare all 8 bytes in a GO  */
>> +	cmpb r9, r10, r9	/* compare s1 and s2  */
>> +	cmpdi cr7, r9, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
>> +	bne cr7, L(process_unaligned_bytes)	/* s1,s2 mismatch found  */
>> +
>> +	addi r5, r3, 8		/* save next offset of s2  */
>> +	addi r11, r4, 8		/* save next offset of s1  */
>> +	ld r8, 8(r4)		/* load s2 at offset=8  */
>> +	li r9, 0		/* load mask=0  */
>> +	cmpb r9, r8, r9		/* compare bytes at s2 with mask  */
>> +	cmpdi cr7, r9, 0	/* NULL found ..?  */
>> +	bne cr7, L(processBytes)/* update input and process bytes one by one  */
>> +
>> +	mr r9, r4		/* save s2  */
>> +	li r10, 0		/* load mask=0  */
>> +
>> +	ld r7, 8(r3)		/* load s1 at offset=8  */
>> +	cmpb r6, r7, r10	/* compare bytes at s1 with mask  */
>> +	cmpdi cr7, r6, 0	/* is NULL found  */
>> +	bne cr7, L(processBytes)/* mismatch, so process one by one  */
>> +
>> +L(unrollDword):
>> +	cmpb r8, r7, r8		/* compare s1 and s2  */
>> +	cmpdi cr7, r8, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
>> +	bne cr7, L(processBytes)/* mismatch with s1 and s2  */
>> +
>> +	addi r5, r3, 16		/* save offset=16 of s1  */
>> +	addi r4, r9, 16		/* save offset=16 of s2  */
>> +	ld r8, 16(r9)		/* load s2 at offset=16  */
>> +	cmpb r7, r8, r10	/* compare bytes at s2 with mask  */
>> +	cmpdi cr7, r7, 0	/* NULL found  ..?  */
>> +	bne cr7, L(update2processBytes)
>> +
>> +	ld r7, 16(r3)		/* load s1 at offset=16  */
>> +	cmpb r6, r7, r10	/* check s1 for end of string  */
>> +	cmpdi cr7, r6, 0	/* end of s1 ?,then handle byte by byte  */
>> +	bne 7,L(update2processBytes)
>> +
>> +	cmpb r8, r7, r8		/* compare s1 and s2 double words  */
>> +	cmpdi cr7, r8, -1	/* compare results with 0xFFFFFFFFFFFFFFFF  */
>> +	bne cr7,L(update2processBytes)
>> +
>> +	addi r5, r3, 24		/* update s1 to offset=24  */
>> +	addi r4, r9, 24		/* update s2 to offset=24  */
>> +
>> +	ld r8, 24(r9)		/* load s2  */
>> +	cmpb r7, r8, r10	/* compare s2 for NULL  */
>> +	cmpdi cr7, r7, 0	/* verify if s2 is ending now  */
>> +	bne cr7,L(update2processBytes)
>> +
>> +	ld r7, 24(r3)		/* load s1 at offset=24  */
>> +	cmpb r6, r7, r10	/* verify for NULL  */
>> +	cmpdi cr7, r6, 0	/* is NULL found  */
>> +	bne cr7, L(update2processBytes)
>> +
>> +	cmpb r8, r7, r8		/* compare s1 and s2  */
>> +	cmpdi cr7, r8, -1	/* are s1 and s2 same ..?  */
>> +	bne cr7, L(update2processBytes)
>> +
>> +	addi r7, r9, 32		/* update s2 to next double word  */
>> +	addi r3, r3, 32		/* update s1 to next double word  */
>> +
>> +	ld r8, 32(r9)		/* load s2  */
>> +	mr r4, r7		/* save s2  */
>> +	cmpb r6, r8, r10	/* compare s2 with NULL  */
>> +	cmpdi cr7, r6, 0	/* end of s2 ..? */
>> +	bne cr7, L(process_unaligned_bytes)
>> +
>> +	ld r6, 0(r3)		/* load and compare s1 for NULL  */
>> +	cmpb r5, r6, r10
>> +	cmpdi cr7, r5, 0
>> +	bne cr7, L(process_unaligned_bytes)
>> +
>> +	cmpb r8, r6, r8		/* compare s1 and s2  */
>> +	cmpdi cr7, r8, -1
>> +	bne cr7, L(process_unaligned_bytes)
>> +
>> +	addi r5, r3, 8		/* increment s1 and d2 here  */
>> +	addi r11, r9, 40
>> +
>> +	ld r8, 40(r9)		/* process s2 now  */
>> +	cmpb r9, r8, r10
>> +	cmpdi cr7, r9, 0
>> +	bne cr7, L(processBytes)
>> +
>> +	mr r9, r7
>> +	ld r7, 8(r3)		/* process s1 now  */
>> +	cmpb r6, r7, r10
>> +	cmpdi cr7, r6, 0
>> +	beq cr7, L(unrollDword)	/* unroll to compare s1 and s2  */
>> +
>> +L(processBytes):
>> +	mr r4, r11		/* update input params  */
>> +	mr r3, r5
>> +
>> +	.p2align 4
>> +L(process_unaligned_bytes):
>> +	lbz r9, 0(r3)		/* load byte from s1  */
>> +	lbz r10, 0(r4)		/* load byte from s2  */
>> +	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
>> +	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
>> +	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
>> +	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
>> +
>> +	lbz r9, 1(r3)		/* load next byte from s1  */
>> +	lbz r10, 1(r4)		/* load next byte from s2  */
>> +	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
>> +	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
>> +	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
>> +	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
>> +
>> +	lbz r9, 2(r3)		/* unroll 3rd byte here  */
>> +	lbz r10, 2(r4)
>> +	cmpdi cr7, r9, 0
>> +	beq cr7, L(diffOfNULL)
>> +	cmplw cr7, r9, r10
>> +	bne 7, L(ComputeDiff)
>> +
>> +	lbz r9, 3(r3)		/* unroll 4th byte now  */
>> +	lbz r10, 3(r4)
>> +	addi r3, r3, 4		/* increment s1 by unroll factor  */
>> +	cmpdi cr7, r9, 0
>> +	cmplw cr6, 9, r10
>> +	beq cr7, L(diffOfNULL)
>> +	addi r4, r4, 4		/* increment s2 by unroll factor  */
>> +	beq cr6, L(process_unaligned_bytes)	/* unroll byte processing  */
>> +
>> +	.p2align 4
>> +L(ComputeDiff):
>> +	extsw r9, r9
>> +	subf r10, r10, r9	/* compute s1 - s2  */
>> +	extsw r3, r10
>> +	blr			/* return  */
>> +
>> +	.p2align 4
>> +L(diffOfNULL):
>> +	li r9, 0
>> +	subf r10, r10, r9	/* compute s1 - s2  */
>> +	extsw r3, r10		/* sign extend result  */
>> +	blr			/* return  */
>> +
>> +	.p2align 4
>> +L(update2processBytes):
>> +	mr r3, r5		/* update and proceed  */
>> +	b L(process_unaligned_bytes)
>> +
>> +END (strcmp)
>> +libc_hidden_builtin_def (strcmp)
Adhemerval Zanella June 11, 2014, 1:49 p.m. UTC | #3 
Thanks, pushed upstream as e23d3d2690bf63207b1a47e83a94693daebbbfe5


On 10-06-2014 13:06, R Vidya wrote:
> Hi Adhemerval , thanks for the review. Yeah , i seem to have forgotten the ChangeLog.
> Here it is:
> -----------------------------------------------------------------------------------------------------------
> 2014-06-05  Vidya Ranganathan  <vidya@linux.vnet.ibm.com>
>
>         * sysdeps/powerpc/powerpc64/power7/strcmp.S: New file: Optimization.
>         * sysdeps/powerpc/powerpc64/multiarch/strcmp.c: New file:
>         multiarch strcmp for PPC64.
>         * sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S: New file
>         * sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S: New file
>         * sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strcmp
>         multiarch optimizations.
>         * sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c:
>         (__libc_ifunc_impl_list): Likewise.
>
> -----------------------------------------------------------------------------------------------------------
>
> On Tuesday 10 June 2014 07:43 PM, Adhemerval Zanella wrote:
>> Hi Vidya,
>>
>> Path looks good, however you forgot to add a ChangeLog.  Also one typo below.
>> Please send the CL entry that will push upstream.
>>
>> On 05-06-2014 02:13, vidya@linux.vnet.ibm.com wrote:
>>
>>> From: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
>>>
>>> Optimization is achieved on 8 byte aligned strings with double word
>>> comparison using cmpb instruction. On unaligned strings loop unrolling
>>> is applied for Power7 gain.
>>>
>>> Signed-off-by: Vidya Ranganathan <vidya@linux.vnet.ibm.com>
>>> ---
>>>   sysdeps/powerpc/powerpc64/multiarch/Makefile       |   2 +-
>>>   .../powerpc/powerpc64/multiarch/ifunc-impl-list.c  |   7 +
>>>   .../powerpc/powerpc64/multiarch/strcmp-power7.S    |  40 +++++
>>>   sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S |  43 +++++
>>>   sysdeps/powerpc/powerpc64/multiarch/strcmp.c       |  31 ++++
>>>   sysdeps/powerpc/powerpc64/power7/strcmp.S          | 195 +++++++++++++++++++++
>>>   6 files changed, 317 insertions(+), 1 deletion(-)
>>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>>>   create mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>>>   create mode 100644 sysdeps/powerpc/powerpc64/power7/strcmp.S
>>>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> index 35020a7..05744e9 100644
>>> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
>>> @@ -17,7 +17,7 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
>>>              strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
>>>              strspn-power7 strspn-ppc64 strcspn-power7 strcspn-ppc64 \
>>>              strpbrk-power7 strpbrk-ppc64 strncpy-power7 strncpy-ppc64 \
>>> -           stpncpy-power7 stpncpy-ppc64
>>> +           stpncpy-power7 stpncpy-ppc64 strcmp-power7 strcmp-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 d8578fb..b3933a5 100644
>>> --- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
>>> @@ -294,5 +294,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>>>             IFUNC_IMPL_ADD (array, i, stpncpy, 1,
>>>                    __stpncpy_ppc))
>>>
>>> +  /* Support sysdeps/powerpc/powerpc64/multiarch/strcmp.c.  */
>>> +  IFUNC_IMPL (i, name, strcmp,
>>> +          IFUNC_IMPL_ADD (array, i, strcmp,
>>> +                  hwcap & PPC_FEATURE_HAS_VSX,
>>> +                  __strcmp_power7)
>>> +          IFUNC_IMPL_ADD (array, i, strcmp, 1,
>>> +                 __strcmp_ppc))
>>>     return i;
>>>   }
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>>> new file mode 100644
>>> index 0000000..790ce8d
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
>>> @@ -0,0 +1,40 @@
>>> +/* Optimized strcmp implementation for POWER7.
>>> +   Copyright (C) 2014 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(__strcmp_power7)                    \
>>> +  .align ALIGNARG(alignt);                    \
>>> +  EALIGN_W_##words;                        \
>>> +  BODY_LABEL(__strcmp_power7):                    \
>>> +  cfi_startproc;                        \
>>> +  LOCALENTRY(__strcmp_power7)
>>> +
>>> +#undef END
>>> +#define END(name)                        \
>>> +  cfi_endproc;                            \
>>> +  TRACEBACK(__strcmp_power7)                    \
>>> +  END_2(__strcmp_power7)
>>> +
>>> +#undef libc_hidden_builtin_def
>>> +#define libc_hidden_builtin_def(name)
>>> +
>>> +#include <sysdeps/powerpc/powerpc64/power7/strcmp.S>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>>> new file mode 100644
>>> index 0000000..93d1277
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
>>> @@ -0,0 +1,43 @@
>>> +/* Default strcmp implementation for PowerPC64.
>>> +   Copyright (C) 2014 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>
>>> +
>>> +#if defined SHARED && !defined NOT_IN_libc
>>> +# undef EALIGN
>>> +# define EALIGN(name, alignt, words)                \
>>> +  .section ".text";                        \
>>> +  ENTRY_2(__strcmp_ppc)                        \
>>> +  .align ALIGNARG(alignt);                    \
>>> +  EALIGN_W_##words;                        \
>>> +  BODY_LABEL(__strcmp_ppc):                    \
>>> +  cfi_startproc;                        \
>>> +  LOCALENTRY(__strcmp_ppc)
>>> +
>>> +# undef END
>>> +# define END(name)                        \
>>> +  cfi_endproc;                            \
>>> +  TRACEBACK(__strcmp_ppc)                    \
>>> +  END_2(__strcmp_ppc)
>>> +
>>> +# undef libc_hidden_builtin_def
>>> +# define libc_hidden_builtin_def(name)                \
>>> +    .globl __GI_strcmp; __GI_strcmp = __strcmp_ppc
>>> +#endif
>>> +
>>> +#include <sysdeps/powerpc/powerpc64/strcmp.S>
>>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>>> new file mode 100644
>>> index 0000000..2013301
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
>>> @@ -0,0 +1,31 @@
>>> +/* Multiple versions of strcmp. PowerPC64 version.
>>> +   Copyright (C) 2014 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 defined SHARED && !defined NOT_IN_libc
>>> +# include <string.h>
>>> +# include <shlib-compat.h>
>>> +# include "init-arch.h"
>>> +
>>> +extern __typeof (strcmp) __strcmp_ppc attribute_hidden;
>>> +extern __typeof (strcmp) __strcmp_power7 attribute_hidden;
>>> +
>>> +libc_ifunc (strcmp,
>>> +            (hwcap & PPC_FEATURE_HAS_VSX)
>>> +            ? __strcmp_power7
>>> +            : __strcmp_ppc);
>>> +#endif
>>> diff --git a/sysdeps/powerpc/powerpc64/power7/strcmp.S b/sysdeps/powerpc/powerpc64/power7/strcmp.S
>>> new file mode 100644
>>> index 0000000..f16a9d8
>>> --- /dev/null
>>> +++ b/sysdeps/powerpc/powerpc64/power7/strcmp.S
>>> @@ -0,0 +1,195 @@
>>> +/* Optimized strcmp implementation for Power7 using 'cmpb' instruction
>>> +   Copyright (C) 2014 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/>.  */
>>> +
>>> +/* The optimization is achieved here through cmpb instruction.
>>> +   8byte aligned strings are processed with double word comparision
>> s/comparision/comparison
>>> +   and unaligned strings are handled effectively with loop unrolling
>>> +   technique  */
>>> +
>>> +#include <sysdep.h>
>>> +
>>> +/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4])  */
>>> +
>>> +EALIGN (strcmp, 4, 0)
>>> +    CALL_MCOUNT 2
>>> +
>>> +    or r9, r3, r4
>>> +    rldicl. r10, r9, 0, 61    /* are s1 and s2 8 byte aligned..?  */
>>> +    bne cr0, L(process_unaligned_bytes)
>>> +
>>> +/* process input parameters on double word aligned boundary  */
>>> +    ld r9, 0(r4)        /* load s2 at offset=0  */
>>> +    li r10, 0        /* load mask=0  */
>>> +    cmpb r10, r9, r10    /* compare bytes at s2 with mask  */
>>> +    cmpdi cr7, r10, 0    /* is NULL found ..? is end of string HIT  */
>>> +    bne cr7, L(process_unaligned_bytes)    /* process byte by byte  */
>>> +
>>> +    ld r10, 0(r3)        /* load s1 at offset=0  */
>>> +    li r8, 0        /* load mask=0  */
>>> +    cmpb r8, r10, r8    /* compare bytes at s1 with mask  */
>>> +    cmpdi cr7, r8, 0    /* is NULL found ..? is end of string HIT  */
>>> +    bne cr7, L(process_unaligned_bytes)    /* process byte by byte  */
>>> +
>>> +/*s1 and s2 does not contain NULL now , so compare all 8 bytes in a GO  */
>>> +    cmpb r9, r10, r9    /* compare s1 and s2  */
>>> +    cmpdi cr7, r9, -1    /* compare result with 0xFFFFFFFFFFFFFFFF  */
>>> +    bne cr7, L(process_unaligned_bytes)    /* s1,s2 mismatch found  */
>>> +
>>> +    addi r5, r3, 8        /* save next offset of s2  */
>>> +    addi r11, r4, 8        /* save next offset of s1  */
>>> +    ld r8, 8(r4)        /* load s2 at offset=8  */
>>> +    li r9, 0        /* load mask=0  */
>>> +    cmpb r9, r8, r9        /* compare bytes at s2 with mask  */
>>> +    cmpdi cr7, r9, 0    /* NULL found ..?  */
>>> +    bne cr7, L(processBytes)/* update input and process bytes one by one  */
>>> +
>>> +    mr r9, r4        /* save s2  */
>>> +    li r10, 0        /* load mask=0  */
>>> +
>>> +    ld r7, 8(r3)        /* load s1 at offset=8  */
>>> +    cmpb r6, r7, r10    /* compare bytes at s1 with mask  */
>>> +    cmpdi cr7, r6, 0    /* is NULL found  */
>>> +    bne cr7, L(processBytes)/* mismatch, so process one by one  */
>>> +
>>> +L(unrollDword):
>>> +    cmpb r8, r7, r8        /* compare s1 and s2  */
>>> +    cmpdi cr7, r8, -1    /* compare result with 0xFFFFFFFFFFFFFFFF  */
>>> +    bne cr7, L(processBytes)/* mismatch with s1 and s2  */
>>> +
>>> +    addi r5, r3, 16        /* save offset=16 of s1  */
>>> +    addi r4, r9, 16        /* save offset=16 of s2  */
>>> +    ld r8, 16(r9)        /* load s2 at offset=16  */
>>> +    cmpb r7, r8, r10    /* compare bytes at s2 with mask  */
>>> +    cmpdi cr7, r7, 0    /* NULL found  ..?  */
>>> +    bne cr7, L(update2processBytes)
>>> +
>>> +    ld r7, 16(r3)        /* load s1 at offset=16  */
>>> +    cmpb r6, r7, r10    /* check s1 for end of string  */
>>> +    cmpdi cr7, r6, 0    /* end of s1 ?,then handle byte by byte  */
>>> +    bne 7,L(update2processBytes)
>>> +
>>> +    cmpb r8, r7, r8        /* compare s1 and s2 double words  */
>>> +    cmpdi cr7, r8, -1    /* compare results with 0xFFFFFFFFFFFFFFFF  */
>>> +    bne cr7,L(update2processBytes)
>>> +
>>> +    addi r5, r3, 24        /* update s1 to offset=24  */
>>> +    addi r4, r9, 24        /* update s2 to offset=24  */
>>> +
>>> +    ld r8, 24(r9)        /* load s2  */
>>> +    cmpb r7, r8, r10    /* compare s2 for NULL  */
>>> +    cmpdi cr7, r7, 0    /* verify if s2 is ending now  */
>>> +    bne cr7,L(update2processBytes)
>>> +
>>> +    ld r7, 24(r3)        /* load s1 at offset=24  */
>>> +    cmpb r6, r7, r10    /* verify for NULL  */
>>> +    cmpdi cr7, r6, 0    /* is NULL found  */
>>> +    bne cr7, L(update2processBytes)
>>> +
>>> +    cmpb r8, r7, r8        /* compare s1 and s2  */
>>> +    cmpdi cr7, r8, -1    /* are s1 and s2 same ..?  */
>>> +    bne cr7, L(update2processBytes)
>>> +
>>> +    addi r7, r9, 32        /* update s2 to next double word  */
>>> +    addi r3, r3, 32        /* update s1 to next double word  */
>>> +
>>> +    ld r8, 32(r9)        /* load s2  */
>>> +    mr r4, r7        /* save s2  */
>>> +    cmpb r6, r8, r10    /* compare s2 with NULL  */
>>> +    cmpdi cr7, r6, 0    /* end of s2 ..? */
>>> +    bne cr7, L(process_unaligned_bytes)
>>> +
>>> +    ld r6, 0(r3)        /* load and compare s1 for NULL  */
>>> +    cmpb r5, r6, r10
>>> +    cmpdi cr7, r5, 0
>>> +    bne cr7, L(process_unaligned_bytes)
>>> +
>>> +    cmpb r8, r6, r8        /* compare s1 and s2  */
>>> +    cmpdi cr7, r8, -1
>>> +    bne cr7, L(process_unaligned_bytes)
>>> +
>>> +    addi r5, r3, 8        /* increment s1 and d2 here  */
>>> +    addi r11, r9, 40
>>> +
>>> +    ld r8, 40(r9)        /* process s2 now  */
>>> +    cmpb r9, r8, r10
>>> +    cmpdi cr7, r9, 0
>>> +    bne cr7, L(processBytes)
>>> +
>>> +    mr r9, r7
>>> +    ld r7, 8(r3)        /* process s1 now  */
>>> +    cmpb r6, r7, r10
>>> +    cmpdi cr7, r6, 0
>>> +    beq cr7, L(unrollDword)    /* unroll to compare s1 and s2  */
>>> +
>>> +L(processBytes):
>>> +    mr r4, r11        /* update input params  */
>>> +    mr r3, r5
>>> +
>>> +    .p2align 4
>>> +L(process_unaligned_bytes):
>>> +    lbz r9, 0(r3)        /* load byte from s1  */
>>> +    lbz r10, 0(r4)        /* load byte from s2  */
>>> +    cmpdi cr7, r9, 0    /* compare *s1 with NULL  */
>>> +    beq cr7, L(diffOfNULL)    /* if *s1 is NULL , return *s1 - *s2  */
>>> +    cmplw cr7, r9, r10    /* compare *s1 and *s2  */
>>> +    bne cr7, L(ComputeDiff)    /* branch to compute difference and return  */
>>> +
>>> +    lbz r9, 1(r3)        /* load next byte from s1  */
>>> +    lbz r10, 1(r4)        /* load next byte from s2  */
>>> +    cmpdi cr7, r9, 0    /* compare *s1 with NULL  */
>>> +    beq cr7, L(diffOfNULL)    /* if *s1 is NULL , return *s1 - *s2  */
>>> +    cmplw cr7, r9, r10    /* compare *s1 and *s2  */
>>> +    bne cr7, L(ComputeDiff)    /* branch to compute difference and return  */
>>> +
>>> +    lbz r9, 2(r3)        /* unroll 3rd byte here  */
>>> +    lbz r10, 2(r4)
>>> +    cmpdi cr7, r9, 0
>>> +    beq cr7, L(diffOfNULL)
>>> +    cmplw cr7, r9, r10
>>> +    bne 7, L(ComputeDiff)
>>> +
>>> +    lbz r9, 3(r3)        /* unroll 4th byte now  */
>>> +    lbz r10, 3(r4)
>>> +    addi r3, r3, 4        /* increment s1 by unroll factor  */
>>> +    cmpdi cr7, r9, 0
>>> +    cmplw cr6, 9, r10
>>> +    beq cr7, L(diffOfNULL)
>>> +    addi r4, r4, 4        /* increment s2 by unroll factor  */
>>> +    beq cr6, L(process_unaligned_bytes)    /* unroll byte processing  */
>>> +
>>> +    .p2align 4
>>> +L(ComputeDiff):
>>> +    extsw r9, r9
>>> +    subf r10, r10, r9    /* compute s1 - s2  */
>>> +    extsw r3, r10
>>> +    blr            /* return  */
>>> +
>>> +    .p2align 4
>>> +L(diffOfNULL):
>>> +    li r9, 0
>>> +    subf r10, r10, r9    /* compute s1 - s2  */
>>> +    extsw r3, r10        /* sign extend result  */
>>> +    blr            /* return  */
>>> +
>>> +    .p2align 4
>>> +L(update2processBytes):
>>> +    mr r3, r5        /* update and proceed  */
>>> +    b L(process_unaligned_bytes)
>>> +
>>> +END (strcmp)
>>> +libc_hidden_builtin_def (strcmp)
>
diff mbox

Patch

diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
index 35020a7..05744e9 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
+++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
@@ -17,7 +17,7 @@  sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
 		   strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
 		   strspn-power7 strspn-ppc64 strcspn-power7 strcspn-ppc64 \
 		   strpbrk-power7 strpbrk-ppc64 strncpy-power7 strncpy-ppc64 \
-		   stpncpy-power7 stpncpy-ppc64
+		   stpncpy-power7 stpncpy-ppc64 strcmp-power7 strcmp-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 d8578fb..b3933a5 100644
--- a/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
@@ -294,5 +294,12 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 	      IFUNC_IMPL_ADD (array, i, stpncpy, 1,
 			     __stpncpy_ppc))
 
+  /* Support sysdeps/powerpc/powerpc64/multiarch/strcmp.c.  */
+  IFUNC_IMPL (i, name, strcmp,
+	      IFUNC_IMPL_ADD (array, i, strcmp,
+			      hwcap & PPC_FEATURE_HAS_VSX,
+			      __strcmp_power7)
+	      IFUNC_IMPL_ADD (array, i, strcmp, 1,
+			     __strcmp_ppc))
   return i;
 }
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
new file mode 100644
index 0000000..790ce8d
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-power7.S
@@ -0,0 +1,40 @@ 
+/* Optimized strcmp implementation for POWER7.
+   Copyright (C) 2014 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(__strcmp_power7)					\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strcmp_power7):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strcmp_power7)
+
+#undef END
+#define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strcmp_power7)					\
+  END_2(__strcmp_power7)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+
+#include <sysdeps/powerpc/powerpc64/power7/strcmp.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
new file mode 100644
index 0000000..93d1277
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp-ppc64.S
@@ -0,0 +1,43 @@ 
+/* Default strcmp implementation for PowerPC64.
+   Copyright (C) 2014 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>
+
+#if defined SHARED && !defined NOT_IN_libc
+# undef EALIGN
+# define EALIGN(name, alignt, words)				\
+  .section ".text";						\
+  ENTRY_2(__strcmp_ppc)						\
+  .align ALIGNARG(alignt);					\
+  EALIGN_W_##words;						\
+  BODY_LABEL(__strcmp_ppc):					\
+  cfi_startproc;						\
+  LOCALENTRY(__strcmp_ppc)
+
+# undef END
+# define END(name)						\
+  cfi_endproc;							\
+  TRACEBACK(__strcmp_ppc)					\
+  END_2(__strcmp_ppc)
+
+# undef libc_hidden_builtin_def
+# define libc_hidden_builtin_def(name)				\
+    .globl __GI_strcmp; __GI_strcmp = __strcmp_ppc
+#endif
+
+#include <sysdeps/powerpc/powerpc64/strcmp.S>
diff --git a/sysdeps/powerpc/powerpc64/multiarch/strcmp.c b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
new file mode 100644
index 0000000..2013301
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strcmp.c
@@ -0,0 +1,31 @@ 
+/* Multiple versions of strcmp. PowerPC64 version.
+   Copyright (C) 2014 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 defined SHARED && !defined NOT_IN_libc
+# include <string.h>
+# include <shlib-compat.h>
+# include "init-arch.h"
+
+extern __typeof (strcmp) __strcmp_ppc attribute_hidden;
+extern __typeof (strcmp) __strcmp_power7 attribute_hidden;
+
+libc_ifunc (strcmp,
+            (hwcap & PPC_FEATURE_HAS_VSX)
+            ? __strcmp_power7
+            : __strcmp_ppc);
+#endif
diff --git a/sysdeps/powerpc/powerpc64/power7/strcmp.S b/sysdeps/powerpc/powerpc64/power7/strcmp.S
new file mode 100644
index 0000000..f16a9d8
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/power7/strcmp.S
@@ -0,0 +1,195 @@ 
+/* Optimized strcmp implementation for Power7 using 'cmpb' instruction
+   Copyright (C) 2014 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/>.  */
+
+/* The optimization is achieved here through cmpb instruction.
+   8byte aligned strings are processed with double word comparision
+   and unaligned strings are handled effectively with loop unrolling
+   technique  */
+
+#include <sysdep.h>
+
+/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4])  */
+
+EALIGN (strcmp, 4, 0)
+	CALL_MCOUNT 2
+
+	or r9, r3, r4
+	rldicl. r10, r9, 0, 61	/* are s1 and s2 8 byte aligned..?  */
+	bne cr0, L(process_unaligned_bytes)
+
+/* process input parameters on double word aligned boundary  */
+	ld r9, 0(r4)		/* load s2 at offset=0  */
+	li r10, 0		/* load mask=0  */
+	cmpb r10, r9, r10	/* compare bytes at s2 with mask  */
+	cmpdi cr7, r10, 0	/* is NULL found ..? is end of string HIT  */
+	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
+
+	ld r10, 0(r3)		/* load s1 at offset=0  */
+	li r8, 0		/* load mask=0  */
+	cmpb r8, r10, r8	/* compare bytes at s1 with mask  */
+	cmpdi cr7, r8, 0	/* is NULL found ..? is end of string HIT  */
+	bne cr7, L(process_unaligned_bytes)	/* process byte by byte  */
+
+/*s1 and s2 does not contain NULL now , so compare all 8 bytes in a GO  */
+	cmpb r9, r10, r9	/* compare s1 and s2  */
+	cmpdi cr7, r9, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
+	bne cr7, L(process_unaligned_bytes)	/* s1,s2 mismatch found  */
+
+	addi r5, r3, 8		/* save next offset of s2  */
+	addi r11, r4, 8		/* save next offset of s1  */
+	ld r8, 8(r4)		/* load s2 at offset=8  */
+	li r9, 0		/* load mask=0  */
+	cmpb r9, r8, r9		/* compare bytes at s2 with mask  */
+	cmpdi cr7, r9, 0	/* NULL found ..?  */
+	bne cr7, L(processBytes)/* update input and process bytes one by one  */
+
+	mr r9, r4		/* save s2  */
+	li r10, 0		/* load mask=0  */
+
+	ld r7, 8(r3)		/* load s1 at offset=8  */
+	cmpb r6, r7, r10	/* compare bytes at s1 with mask  */
+	cmpdi cr7, r6, 0	/* is NULL found  */
+	bne cr7, L(processBytes)/* mismatch, so process one by one  */
+
+L(unrollDword):
+	cmpb r8, r7, r8		/* compare s1 and s2  */
+	cmpdi cr7, r8, -1	/* compare result with 0xFFFFFFFFFFFFFFFF  */
+	bne cr7, L(processBytes)/* mismatch with s1 and s2  */
+
+	addi r5, r3, 16		/* save offset=16 of s1  */
+	addi r4, r9, 16		/* save offset=16 of s2  */
+	ld r8, 16(r9)		/* load s2 at offset=16  */
+	cmpb r7, r8, r10	/* compare bytes at s2 with mask  */
+	cmpdi cr7, r7, 0	/* NULL found  ..?  */
+	bne cr7, L(update2processBytes)
+
+	ld r7, 16(r3)		/* load s1 at offset=16  */
+	cmpb r6, r7, r10	/* check s1 for end of string  */
+	cmpdi cr7, r6, 0	/* end of s1 ?,then handle byte by byte  */
+	bne 7,L(update2processBytes)
+
+	cmpb r8, r7, r8		/* compare s1 and s2 double words  */
+	cmpdi cr7, r8, -1	/* compare results with 0xFFFFFFFFFFFFFFFF  */
+	bne cr7,L(update2processBytes)
+
+	addi r5, r3, 24		/* update s1 to offset=24  */
+	addi r4, r9, 24		/* update s2 to offset=24  */
+
+	ld r8, 24(r9)		/* load s2  */
+	cmpb r7, r8, r10	/* compare s2 for NULL  */
+	cmpdi cr7, r7, 0	/* verify if s2 is ending now  */
+	bne cr7,L(update2processBytes)
+
+	ld r7, 24(r3)		/* load s1 at offset=24  */
+	cmpb r6, r7, r10	/* verify for NULL  */
+	cmpdi cr7, r6, 0	/* is NULL found  */
+	bne cr7, L(update2processBytes)
+
+	cmpb r8, r7, r8		/* compare s1 and s2  */
+	cmpdi cr7, r8, -1	/* are s1 and s2 same ..?  */
+	bne cr7, L(update2processBytes)
+
+	addi r7, r9, 32		/* update s2 to next double word  */
+	addi r3, r3, 32		/* update s1 to next double word  */
+
+	ld r8, 32(r9)		/* load s2  */
+	mr r4, r7		/* save s2  */
+	cmpb r6, r8, r10	/* compare s2 with NULL  */
+	cmpdi cr7, r6, 0	/* end of s2 ..? */
+	bne cr7, L(process_unaligned_bytes)
+
+	ld r6, 0(r3)		/* load and compare s1 for NULL  */
+	cmpb r5, r6, r10
+	cmpdi cr7, r5, 0
+	bne cr7, L(process_unaligned_bytes)
+
+	cmpb r8, r6, r8		/* compare s1 and s2  */
+	cmpdi cr7, r8, -1
+	bne cr7, L(process_unaligned_bytes)
+
+	addi r5, r3, 8		/* increment s1 and d2 here  */
+	addi r11, r9, 40
+
+	ld r8, 40(r9)		/* process s2 now  */
+	cmpb r9, r8, r10
+	cmpdi cr7, r9, 0
+	bne cr7, L(processBytes)
+
+	mr r9, r7
+	ld r7, 8(r3)		/* process s1 now  */
+	cmpb r6, r7, r10
+	cmpdi cr7, r6, 0
+	beq cr7, L(unrollDword)	/* unroll to compare s1 and s2  */
+
+L(processBytes):
+	mr r4, r11		/* update input params  */
+	mr r3, r5
+
+	.p2align 4
+L(process_unaligned_bytes):
+	lbz r9, 0(r3)		/* load byte from s1  */
+	lbz r10, 0(r4)		/* load byte from s2  */
+	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
+	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
+	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
+	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
+
+	lbz r9, 1(r3)		/* load next byte from s1  */
+	lbz r10, 1(r4)		/* load next byte from s2  */
+	cmpdi cr7, r9, 0	/* compare *s1 with NULL  */
+	beq cr7, L(diffOfNULL)	/* if *s1 is NULL , return *s1 - *s2  */
+	cmplw cr7, r9, r10	/* compare *s1 and *s2  */
+	bne cr7, L(ComputeDiff)	/* branch to compute difference and return  */
+
+	lbz r9, 2(r3)		/* unroll 3rd byte here  */
+	lbz r10, 2(r4)
+	cmpdi cr7, r9, 0
+	beq cr7, L(diffOfNULL)
+	cmplw cr7, r9, r10
+	bne 7, L(ComputeDiff)
+
+	lbz r9, 3(r3)		/* unroll 4th byte now  */
+	lbz r10, 3(r4)
+	addi r3, r3, 4		/* increment s1 by unroll factor  */
+	cmpdi cr7, r9, 0
+	cmplw cr6, 9, r10
+	beq cr7, L(diffOfNULL)
+	addi r4, r4, 4		/* increment s2 by unroll factor  */
+	beq cr6, L(process_unaligned_bytes)	/* unroll byte processing  */
+
+	.p2align 4
+L(ComputeDiff):
+	extsw r9, r9
+	subf r10, r10, r9	/* compute s1 - s2  */
+	extsw r3, r10
+	blr			/* return  */
+
+	.p2align 4
+L(diffOfNULL):
+	li r9, 0
+	subf r10, r10, r9	/* compute s1 - s2  */
+	extsw r3, r10		/* sign extend result  */
+	blr			/* return  */
+
+	.p2align 4
+L(update2processBytes):
+	mr r3, r5		/* update and proceed  */
+	b L(process_unaligned_bytes)
+
+END (strcmp)
+libc_hidden_builtin_def (strcmp)