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

[Valeriy Dmitriev via Phabricator via llvm-commits]

vdmitrie added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:11948-11952
+    SmallVector<Value *, 16> BuildVectorOpds;
+    SmallVector<Value *, 16> BuildVectorInsts;
+    if (!findBuildAggregate(I, TTI, BuildVectorOpds, BuildVectorInsts))
+      continue;
+
----------------
ABataev wrote:
> I think you're doing it too early, need to do it after the vectorizeHorReduction, which should start with I, otherwise we may miss single insertelement instruction which has reduction.
You probably meant to make another call to vectorizeHorReduction if we did not match a vector build. I'll try to reproduce the situation you described in a test case.



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

https://reviews.llvm.org/D132590