[all-commits] [llvm/llvm-project] 6c56cf: [DAG] FoldSetCC - add missing icmp(X, undef) -> isT...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6c56cf71ee82ec3a28e0dfc2b751bd10c16929da
      https://github.com/llvm/llvm-project/commit/6c56cf71ee82ec3a28e0dfc2b751bd10c16929da
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2023-09-13 (Wed, 13 Sep 2023)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/test/CodeGen/AArch64/pr55178.ll
    M llvm/test/CodeGen/AMDGPU/swdev373493.ll
    M llvm/test/CodeGen/PowerPC/p10-spill-crgt.ll
    M llvm/test/CodeGen/PowerPC/pr45709.ll
    M llvm/test/CodeGen/RISCV/pr64503.ll
    M llvm/test/CodeGen/Thumb2/ldr-str-imm12.ll
    M llvm/test/CodeGen/WebAssembly/pr59626.ll
    M llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll
    M llvm/test/CodeGen/X86/ragreedy-hoist-spill.ll
    M llvm/test/CodeGen/X86/tail-dup-merge-loop-headers.ll
    M llvm/test/CodeGen/X86/twoaddr-lea.ll
    M llvm/test/CodeGen/X86/vec_int_to_fp.ll

  Log Message:
  -----------
  [DAG] FoldSetCC - add missing icmp(X,undef) -> isTrueWhenEqual case

Followup to D59363 which failed to handle the icmp(X,undef) -> isTrueWhenEqual case - similar to llvm::ConstantFoldCompareInstruction

As discussed on the review, this is affecting some previously reduced test cases, but will also prevent reductions from relying on this inconsistent behaviour in the future.

Differential Revision: https://reviews.llvm.org/D158068