[PATCH] D100486: [COST]Improve cost model for shuffles in SLP.

Fri Apr 16 06:30:48 PDT 2021

ABataev added inline comments.

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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:3620-3621
+            TargetTransformInfo::SK_PermuteSingleSrc;
+        if (ShuffleVectorInst::isReverseMask(NewMask))
+          SK = TargetTransformInfo::SK_Reverse;
+        CommonCost = TTI->getShuffleCost(SK, VecTy, NewMask);
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RKSimon wrote:
> sdesmalen wrote:
> > Can the finding of a more specific ShuffleKind be done by getShuffleCost when a Mask is given?
> > It seems a bit inconvenient to have to do that manually before calling this function.
> I made a similar comment on D100495 - we could do with a generic 'ShuffleKind' decoder helper function (e.g. in Analysis\VectorUtils.h) that everybody can use.
In this case, we need to update `getShuffleCost` function for all the targets to translate the mask. Is it ok if I'll do it in this patch?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100486/new/

https://reviews.llvm.org/D100486