[all-commits] [llvm/llvm-project] a0d457: [X86] foldMaskAndShiftToScale - use MaskedValueIsZ...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a0d457bceca90122c7f9c1fef451f58208f92c6f
      https://github.com/llvm/llvm-project/commit/a0d457bceca90122c7f9c1fef451f58208f92c6f
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2023-08-24 (Thu, 24 Aug 2023)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

  Log Message:
  -----------
  [X86] foldMaskAndShiftToScale - use MaskedValueIsZero to test for all-zero upper bits

We were testing for an exact match of zero bits which isn't necessary (we don't care if lower bits are zero) - by inspection as its proven tricky to get a decent test case.

Noticed while clearing up D155472 regressions