[PATCH] D88569: [DAGCombiner] Call SimplifyDemandedBits to simplify EXTRACT_VECTOR_ELT

[Jay Foad via Phabricator via llvm-commits]

foad added a comment.

> Maybe in such a case where a buildvector have elts which are extracted from the same vector, you shouldn't SimplifyDemandedBits for extract_vector_elt.

Yes, I am coming round to this idea: don't simplify EXTRACT_VECTOR_ELT to a constant if it is used by BUILD_VECTOR, because of the risk of breaking things like shuffle patterns.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D88569/new/

https://reviews.llvm.org/D88569