[PATCH] D132590: [SLP] Try to match reductions first in a vector build sequence.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:11820-11823
+  SmallVector<WeakTrackingVH> PostponedInsts;
+  for (Value *Op : BuildVectorOpds)
+    OpsChanged |=
+        vectorizeHorReduction(nullptr, Op, BB, R, TTI, PostponedInsts);
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vdmitrie wrote:
> ABataev wrote:
> > Why do you want still call this after `findBuildAggregate`?
> In order to match hor reduction on build vector operands. Can you offer other approach to do the same?
But vectorizeRootInstruction already does this, why do you want to do it twice, here and in vectorizeRootInstruction? It increases compile time.
Can we just call vectorizeRootInstruction(nullptr, I, BB, R, TTI); and vectorizeBuildVector after? And remove this loop and final OpsChanged |= tryToVectorize(PostponedInsts, R); call?


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  https://reviews.llvm.org/D132590/new/

https://reviews.llvm.org/D132590