[all-commits] [llvm/llvm-project] a0fcf8: [LV] Consider if scalar epilogue is required in ge...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a0fcf84a8c4d953730170f8f2da17a7556991607
      https://github.com/llvm/llvm-project/commit/a0fcf84a8c4d953730170f8f2da17a7556991607
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2023-07-06 (Thu, 06 Jul 2023)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/test/Transforms/LoopVectorize/X86/limit-vf-by-tripcount.ll
    M llvm/test/Transforms/LoopVectorize/X86/pr56319-vector-exit-cond-optimization-epilogue-vectorization.ll

  Log Message:
  -----------
  [LV] Consider if scalar epilogue is required in getMaximizedVFForTarget.

When a scalar epilogue is required, at least one iteration of the scalar loop
has to execute. Adjust ConstTripCount accordingly to avoid picking a max VF
that results in a dead vector loop.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D154261