[PATCH] D114375: [SLP]Fix emission of int division with some undef vector subelements.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev created this revision.
ABataev added reviewers: RKSimon, anton-afanasyev, dtemirbulatov, vporpo.
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If it is legal and profitable to vectorize integer division operations
and some of the operands are undefs, need to replace these undefs in the
vector operands elements with some actual values. Otherwise, such
division operations will be replaced by the vector poison values in the
instcombiner. It leads to incorrect llvm ir per https://llvm.org/docs/LangRef.html#poisonvalues. According to this document "Vector elements may be independently poisoned. Therefore, transforms on instructions such as shufflevector must be careful to propagate poison across values or elements only as allowed by the original code."


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D114375

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/arith-div-undef.ll
  llvm/test/Transforms/SLPVectorizer/X86/shrink_after_reorder2.ll

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