[PATCH] D87698: [SelectionDAG] Check any use of negation result before removal

[Qiu Chaofan via Phabricator via llvm-commits]

qiucf created this revision.
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D87614 <https://reviews.llvm.org/D87614> fixed a bug about constant removal in negation. But after sanitizing check I found there's still some issue about it so it's reverted.

Temporary nodes will be removed if useless in negation. Before the removal, they'd be checked if any other nodes used it. So the removal was moved after `getNode`. However in rare cases the node to be removed is the same as result of `getNode`. We missed that.

The part is fragile, so we need to be careful about it..


https://reviews.llvm.org/D87698

Files:
  llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
  llvm/test/CodeGen/X86/pr47517.ll

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