[all-commits] [llvm/llvm-project] eeeb18: [X86] Change the behavior of canWidenShuffleElemen...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: eeeb18cd075ddf7a44c8571f9e17e4b1fcbc8aa4
      https://github.com/llvm/llvm-project/commit/eeeb18cd075ddf7a44c8571f9e17e4b1fcbc8aa4
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2019-11-01 (Fri, 01 Nov 2019)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    A llvm/test/CodeGen/X86/pr43866.ll

  Log Message:
  -----------
  [X86] Change the behavior of canWidenShuffleElements used by lowerV2X128Shuffle to match the behavior in lowerVectorShuffle with regards to zeroable elements.

Previously we marked zeroable elements in a way that prevented
the widening check from recognizing that it could widen. Now
we only mark them zeroable if V2 is an all zeros vector. This
matches what we do for widening elements in lowerVectorShuffle.

Fixes PR43866.