[PATCH] D133441: [SLP] Look ahead for mutual horizontal reductions.

[Alexandros Lamprineas via Phabricator via llvm-commits]

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When we try to reduce a horizontal reduction which has external users, the vectorization may be considered unprofitable because of the scalar extraction cost. However, we sometimes encounter mutual reductions cancelling each other out without actually having to extract any scalars. This fixes issue #55350 <https://github.com/llvm/llvm-project/issues/55350>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133441

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/AArch64/multiple_reduction.ll

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