[PATCH] D37227: [SCEV] Ensure ScalarEvolution::createAddRecFromPHIWithCastsImpl is working with an add expression.

[Philip Reames via Phabricator via llvm-commits]

reames requested changes to this revision.
reames added inline comments.
This revision now requires changes to proceed.


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Comment at: lib/Analysis/ScalarEvolution.cpp:4387
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   const SCEV *BEValue = getSCEV(BEValueV);
 
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I think you've misdiagnosed the bug here.  getSCEV is supposed to always return a SCEV for a value when requested.  It may return SCEVUnknown, but that's still a valid SCEV.  As such, the check for AddRec just below this should prevent the xor flowing through.  I suspect you're actual issue is that getSCEV has return nullptr.

p.s. I suggest chatting with Max or Sanjoy to confirm everything I just said.  I'm not SCEV expert.


https://reviews.llvm.org/D37227