[PATCH] powerpc: Fix IFUNC for memrchr

[Rajalakshmi Srinivasaraghavan]

On 10/05/2017 07:18 PM, Adhemerval Zanella wrote:
> 
> 
> On 05/10/2017 07:43, Rajalakshmi Srinivasaraghavan wrote:
>> Recent commit 59ba2d2b5421 missed to add __memrchr_power8 in
>> ifunc list.  Also handled discarding unwanted bytes for
>> unaligned inputs in power8 optimization.
>>
>> 2017-10-05  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>
>>
>> 	* sysdeps/powerpc/powerpc64/multiarch/memrchr-ppc64.c: Revert
>> 	back to powerpc32 file.
>> 	* sysdeps/powerpc/powerpc64/multiarch/memrchr.c
>> 	(memrchr): Add __memrchr_power8 to ifunc list.
>> 	* sysdeps/powerpc/powerpc64/power8/memrchr.S: Mask
>> 	extra bytes for unaligned inputs.
>> ---
>>   .../powerpc/powerpc64/multiarch/memrchr-ppc64.c    | 15 +-------------
>>   sysdeps/powerpc/powerpc64/multiarch/memrchr.c      |  3 +++
>>   sysdeps/powerpc/powerpc64/power8/memrchr.S         | 24 ++++++++++++++++++++++
>>   3 files changed, 28 insertions(+), 14 deletions(-)
>>
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/memrchr-ppc64.c b/sysdeps/powerpc/powerpc64/multiarch/memrchr-ppc64.c
>> index be24689336..e2d53ac0f4 100644
>> --- a/sysdeps/powerpc/powerpc64/multiarch/memrchr-ppc64.c
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/memrchr-ppc64.c
>> @@ -15,17 +15,4 @@
>>      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 MEMRCHR  __memrchr_ppc
>> -
>> -#undef weak_alias
>> -#define weak_alias(a, b)
>> -
>> -#undef libc_hidden_builtin_def
>> -#define libc_hidden_builtin_def(name)
>> -
>> -extern __typeof (memrchr) __memrchr_ppc attribute_hidden;
>> -
>> -#include <string/memrchr.c>
>> +#include <sysdeps/powerpc/powerpc32/power4/multiarch/memrchr-ppc32.c>
>> diff --git a/sysdeps/powerpc/powerpc64/multiarch/memrchr.c b/sysdeps/powerpc/powerpc64/multiarch/memrchr.c
>> index fb09fdf89c..441598ace5 100644
>> --- a/sysdeps/powerpc/powerpc64/multiarch/memrchr.c
>> +++ b/sysdeps/powerpc/powerpc64/multiarch/memrchr.c
>> @@ -23,10 +23,13 @@
>>   
>>   extern __typeof (__memrchr) __memrchr_ppc attribute_hidden;
>>   extern __typeof (__memrchr) __memrchr_power7 attribute_hidden;
>> +extern __typeof (__memrchr) __memrchr_power8 attribute_hidden;
>>   
>>   /* Avoid DWARF definition DIE on ifunc symbol so that GDB can handle
>>      ifunc symbol properly.  */
>>   libc_ifunc (__memrchr,
>> +	    (hwcap2 & PPC_FEATURE2_ARCH_2_07)
>> +	    ? __memrchr_power8 :
>>   	    (hwcap & PPC_FEATURE_HAS_VSX)
>>               ? __memrchr_power7
>>               : __memrchr_ppc);
> 
> I think indentation is a little off here, compared to other ifunc implementations.
> Something like.
> 
>      (hwcap2 & PPC_FEATURE2_ARCH_2_07)
>      ? __memrchr_power8 :
>        (hwcap & PPC_FEATURE_HAS_VSX)
>        ? __memrchr_power7
>      : __memrchr_ppc);

Ack

> 
>> diff --git a/sysdeps/powerpc/powerpc64/power8/memrchr.S b/sysdeps/powerpc/powerpc64/power8/memrchr.S
>> index 521b3c84a2..22b01ec69c 100644
>> --- a/sysdeps/powerpc/powerpc64/power8/memrchr.S
>> +++ b/sysdeps/powerpc/powerpc64/power8/memrchr.S
>> @@ -233,11 +233,35 @@ L(found):
>>   #endif
>>   	addi	r8, r8, 63
>>   	sub	r3, r8, r6	/* Compute final address.  */
>> +	cmpld	cr7, r3, r10
>> +	bgelr	cr7
>> +	li	r3, 0
>>   	blr
>>   
>>   	/* Found a match in last 16 bytes.  */
>>   	.align	4
>>   L(found_16B):
>> +	cmpld	r8, r10		/* Are we on the last QW?  */
>> +	bge	L(last)
>> +	/* Now discard bytes before starting address.  */
>> +	sub	r9, r10, r8
>> +	MTVRD(v9, r9)
>> +	vspltisb	v8, 3
>> +	/* Mask unwanted bytes.  */
>> +#ifdef __LITTLE_ENDIAN__
>> +	lvsr	v7, 0, r10
>> +	vperm   v6, v0, v6, v7
>> +	vsldoi	v9, v0, v9, 8
>> +	vsl	v9, v9, v8
>> +	vslo	v6, v6, v9
>> +#else
>> +	lvsl	v7, 0, r10
>> +	vperm   v6, v6, v0, v7
>> +	vsldoi	v9, v0, v9, 8
>> +	vsl	v9, v9, v8
>> +	vsro	v6, v6, v9
>> +#endif
>> +L(last):
>>   	/* Permute the first bit of each byte into bits 48-63.  */
>>   	VBPERMQ(v6, v6, v10)
>>   	/* Shift each component into its correct position for merging.  */
> 
> Isn't already covered by a testcase? If not, could you add one to test-memrchr?

Already covered in string/tester.c.

> 
> 

-- 
Thanks
Rajalakshmi S