[all-commits] [llvm/llvm-project] e6b85c: [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: e6b85c30276d8e35ed302b2defd7d17637d6edb3
      https://github.com/llvm/llvm-project/commit/e6b85c30276d8e35ed302b2defd7d17637d6edb3
  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
    M llvm/test/Transforms/SampleProfile/pseudo-probe-peep.ll

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

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.

Reapplied after reversion at e1e3c75c7dad72 with a tweak to the pseudo-probe-peep.ll test

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