[PATCH] D124867: [SLP][NFC] Pre-commit test showing horizontal reduction preventing FMA

Tue May 17 07:24:45 PDT 2022

ABataev added a comment.

In D124867#3519126 <https://reviews.llvm.org/D124867#3519126>, @wjschmidt wrote:

> In D124867#3506308 <https://reviews.llvm.org/D124867#3506308>, @ABataev wrote:
>
>> In D124867#3506211 <https://reviews.llvm.org/D124867#3506211>, @wjschmidt wrote:
>>
>>> In D124867#3506146 <https://reviews.llvm.org/D124867#3506146>, @ABataev wrote:
>>>
>>>> The undefs still here.
>>>
>>> Yes, see above -- I was unable to find a sequence without the undefs that causes the horizontal reduction to kick in.
>>
>> Use -slp-threshold option to avoid problems with the cost.
>
> Thanks for the helpful suggestion!  I was able to remove the undefs with a slight adjustment.  I also ran across another FMA-inhibiting variant that I want to look at before re-posting.  I appreciate the feedback.

You're welcome!

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