[PATCH] D97406: [Vectorizers]Improve emission of logical or/and reductions.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev created this revision.
ABataev added reviewers: spatel, RKSimon, dtemirbulatov, anton-afanasyev.
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For logical or/and reductions we emit regular intrinsics @llvm.vector.reduce.or/and.vxi1 calls.
These intrinsics are not effective for the logical or/and reductions,
especially if the optimizer is able to emit short circuit versions of
the scalar or/and instructions and vector code gets less effective than
the scalar version.
Instead, or reduction for i1 can be represented as:

  %val = bitcast <ReduxWidth x i1> to iReduxWidth
  %res = cmp ne iReduxWidth %val, 0

and reduction for i1 can be represented as:

  %val = bitcast <ReduxWidth x i1> to iReduxWidth
  %res = cmp eq iReduxWidth %val, 11111

This improves perfromance of the vector code significantly and make it
to outperform short circuit scalar code.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97406

Files:
  llvm/lib/Transforms/Utils/LoopUtils.cpp
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/compare-reduce.ll

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