[all-commits] [llvm/llvm-project] b2ffc8: [DAG] getNode() - begin generalizing the (zext (tr...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b2ffc867ada60fde361c198dfc31d9c90f70e1aa
      https://github.com/llvm/llvm-project/commit/b2ffc867ada60fde361c198dfc31d9c90f70e1aa
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2023-09-18 (Mon, 18 Sep 2023)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

  Log Message:
  -----------
  [DAG] getNode() - begin generalizing the (zext (trunc (assertzext x))) -> (assertzext x) fold.

We'll need to generalize this fold to check for any zero upperbits to address some of the D155472 regressions, but this exposes a number of issues. For now, just use the general MaskedValueIsZero test instead of the assertzext.