[all-commits] [llvm/llvm-project] de7cee: [X86] getBT - attempt to peek through aext(and(tru...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: de7cee24b6fe97cc11225b20853ea97532a1c2e9
      https://github.com/llvm/llvm-project/commit/de7cee24b6fe97cc11225b20853ea97532a1c2e9
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2022-04-28 (Thu, 28 Apr 2022)

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

  Log Message:
  -----------
  [X86] getBT - attempt to peek through aext(and(trunc(x),c)) mask/modulo

Ideally we'd fold this with generic DAGCombiner, but that only works for !isTruncateFree cases - we might be able to adapt IsDesirableToPromoteOp to find truncated src ops in the future, but for now just use this peephole.

Noticed in Issue #55138