[PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ #21966]

[PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ #21966]

[H.J. Lu]

Since the AVX2 version of mathvec functions uses FMA, it can only be
used when FMA is usable.

Any comments?

Andrew, please take a look and check if it should be fixed on branches.

Thanks.

H.J.
	[BZ #21966]
	* sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
	(IFUNC_SELECTOR): Don't use the AVX2 version if FMA isn't
	usable.
---
 sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
index a43d4c54fa..ccda2748c5 100644
--- a/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
+++ b/sysdeps/x86_64/fpu/multiarch/ifunc-mathvec-avx2.h
@@ -31,7 +31,8 @@ IFUNC_SELECTOR (void)
 {
   const struct cpu_features* cpu_features = __get_cpu_features ();
 
-  if (CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
+  if (CPU_FEATURES_ARCH_P (cpu_features, FMA_Usable)
+      && CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable))
     return OPTIMIZE (avx2);
 
   return OPTIMIZE (sse_wrapper);
-- 
2.13.5

RE: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ #21966]

[Senkevich, Andrew]

> -----Original Message-----
> From: Lu, Hongjiu
> Sent: Friday, August 18, 2017 01:01
> To: GNU C Library <libc-alpha@sourceware.org>
> Cc: Senkevich, Andrew <andrew.senkevich@intel.com>
> Subject: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ
> #21966]
> 
> Since the AVX2 version of mathvec functions uses FMA, it can only be used when
> FMA is usable.
> 
> Any comments?
> 
> Andrew, please take a look and check if it should be fixed on branches.

Yes, branches should be fixed also. Thanks.


--
Andrew

Re: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ #21966]

[H.J. Lu]

On Fri, Aug 18, 2017 at 6:02 AM, Senkevich, Andrew
<andrew.senkevich@intel.com> wrote:
>> -----Original Message-----
>> From: Lu, Hongjiu
>> Sent: Friday, August 18, 2017 01:01
>> To: GNU C Library <libc-alpha@sourceware.org>
>> Cc: Senkevich, Andrew <andrew.senkevich@intel.com>
>> Subject: [PATCH] x86-64: Check FMA_Usable in ifunc-mathvec-avx2.h [BZ
>> #21966]
>>
>> Since the AVX2 version of mathvec functions uses FMA, it can only be used when
>> FMA is usable.
>>
>> Any comments?
>>
>> Andrew, please take a look and check if it should be fixed on branches.
>
> Yes, branches should be fixed also. Thanks.
>

Hi Andrew,

I checked my patch into master branch.  Can you take care of
branches?

Thanks.

-- 
H.J.