[PATCH, PR 49089] Don't split AVX256 unaligned loads by default on bdver1 and generic

H.J. Lu hjl.tools@gmail.com
Fri Jun 17 01:10:00 GMT 2011


On Thu, Jun 16, 2011 at 4:54 PM, Fang, Changpeng <Changpeng.Fang@amd.com> wrote:
> Hi,
>
>  I modify the patch to disable unaligned load splitting only for bdver1 at this moment.
> Unaligned load splitting degrades CFP2006 by 1.3% in geomean for both -mtune=bdver1 and
> -mtune=generic on Bulldozer. However, we agree with H.J's suggestion to determine
> the optimal optimization sets for modern cpus.
>
> Is is OK to commit the attached patch?
>
> Thanks,

Why not just move AVX256_SPLIT_UNALIGNED_STORE
and AVX256_SPLIT_UNALIGNED_LOAD to ix86_tune_indices?

H.J.
> Changpeng
>
>
>
>>> So, is it OK to commit this patch to trunk, and H.J's original patch + this to 4.6 branch?
>>>
>>>
>
>>I have no problems on -mtune=Bulldozer.  But I object -mtune=generic
>>change and did suggest a different approach for -mtune=generic.
>
>
> .
>
>



-- 
H.J.



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