[PATCH] D111810: [DebugInfo][LSR] Add more stringent checks on IV selection and cached dbg.value location-op SCEVs

[Chris Jackson via Phabricator via llvm-commits]

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Reported in Bug PR52161 <https://bugs.llvm.org/show_bug.cgi?id=52161>, there were two issues.

1. That IVs with SCEVs containing 'undef' could be selected. This would lead to fruitless salvage attempts.
2. Sometimes dbg.value arguments were cached along with a SCEVUnknown type for the value. Effectively this SCEV is a value, so no scev-based salvaging can usefully be performed in this case.




https://reviews.llvm.org/D111810

Files:
  llvm/include/llvm/Analysis/ScalarEvolution.h
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
  llvm/test/Transforms/LoopStrengthReduce/pr52161.ll

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