[PATCH] D147798: [LV] Improve VF-aware uniformity checks by handling LShr.

[Vasileios Porpodas via Phabricator via llvm-commits]

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Until now the VF-aware uniformity check would only check for division `i/NUM`.
This patch extends it to support shift-rights, like: `i >> N`.
So the access to `A[i>>2]` in the following loop will no longer be considered
a gather for a VF of 4.

  for (i = 0; i != N; ++i)
    ... = ... A[i>>2]


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147798

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
  llvm/test/Transforms/LoopVectorize/X86/uniform_across_vf.ll

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