[all-commits] [llvm/llvm-project] b9e467: [DAG] canCreateUndefOrPoison - add handling for AD...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b9e4679976e247b4b46454a78b8c212ebbfa7221
      https://github.com/llvm/llvm-project/commit/b9e4679976e247b4b46454a78b8c212ebbfa7221
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2025-06-30 (Mon, 30 Jun 2025)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    M llvm/test/CodeGen/X86/freeze-binary.ll

  Log Message:
  -----------
  [DAG] canCreateUndefOrPoison - add handling for ADD/SUB/MUL overflow nodes (#146322)

Neither the arithmetic value or overflow result can create undef/poison from regular operands values.

We have complete test coverage for all ADDO/SUBO nodes, 32-bit codegen handles the _CARRY variants but until #145939 lands AND DAGCombiner::visitFREEZE handles multiple results we can't see any codegen change.

Pulled out of #145939



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