[PATCH] D57398: SimplifyDemandedVectorElts for all intrinsics

[Philip Reames via Phabricator via llvm-commits]

reames added a comment.

In D57398#1377731 <https://reviews.llvm.org/D57398#1377731>, @RKSimon wrote:

> In D57398#1377469 <https://reviews.llvm.org/D57398#1377469>, @reames wrote:
>
> > In D57398#1376798 <https://reviews.llvm.org/D57398#1376798>, @RKSimon wrote:
> >
> > > future patches should hopefully be able to move more of the SimplifyDemandedVectorElts/SimplifyDemandedVectorEltsLow code over.
> >
> >
> > Not sure what you mean here.  Over to where? from where?
>
>
> I meant for cases like the SimplifyDemandedVectorEltsLow call in Intrinsic::x86_vcvtph2ps_128/256 which can now be removed and similar code moved into InstCombiner::SimplifyDemandedVectorElts so it is correctly handled within a recursive call. Not all intrinsics would work, but some are probably worth it.


Ah, yes.  I don't plan to focus on the x86 specific intrinsics, but I agree that would be a worthwhile cleanup.

At a high level, do you know why we need these intrinsics at all?  What are they expressing which can be well represented/pattern matched from normal IR?


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