[PATCH] D108837: [SimplifyCFG] Ignore free instructions when computing cost for folding branch to common dest

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

Seems to be in the code added recently in https://reviews.llvm.org/rG909cba969981032c5740774ca84a34b7f76b909b

with

  diff --cc llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  index ac386761e12b,ac386761e12b..32bba11659e7
  --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  @@@ -1107,6 -1107,6 +1107,9 @@@ static void CloneInstructionsIntoPredec
          auto *UI = cast<Instruction>(U.getUser());
          auto *PN = dyn_cast<PHINode>(UI);
          if (!PN) {
  ++        BonusInst.dump();
  ++        UI->dump();
  ++        errs() << (UI->getParent() == BB) << " " << BonusInst.comesBefore(UI) << "\n";
            assert(UI->getParent() == BB && BonusInst.comesBefore(UI) &&
                   "If the user is not a PHI node, then it should be in the same "
                   "block as, and come after, the original bonus instruction.");

I'm seeing

    %.old = bitcast [1 x i64]* undef to i8*
    call void @llvm.lifetime.start.p0i8(i64 8, i8* %.old)
  0 opt: ../../llvm/lib/IR/Instruction.cpp:114: bool llvm::Instruction::comesBefore(const llvm::Instruction *) const: Assertion `Parent == Other->Parent && "cross-BB instruction order comparison"' failed.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108837/new/

https://reviews.llvm.org/D108837