[all-commits] [llvm/llvm-project] f126e8: [SLPVectorizer] Ignore unreachable blocks

[Harald van Dijk via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f126e8ec2873ceedde53d2ccee1a66a83620e9a6
      https://github.com/llvm/llvm-project/commit/f126e8ec2873ceedde53d2ccee1a66a83620e9a6
  Author: Harald van Dijk <harald at gigawatt.nl>
  Date:   2021-06-01 (Tue, 01 Jun 2021)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Transforms/SLPVectorizer/X86/unreachable.ll

  Log Message:
  -----------
  [SLPVectorizer] Ignore unreachable blocks

As the existing test unreachable.ll shows, we should be doing more
work to avoid entering unreachable blocks: we should not stop
vectorization just because a PHI incoming value from an unreachable
block cannot be vectorized. We know that particular value will never
be used so we can just replace it with poison.