[PATCH] D128586: [SCEV] Use SCEVUnknown(poison) instead of SCEVUnknown(undef).

[Florian Hahn via Phabricator via llvm-commits]

fhahn added inline comments.


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Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:7199
     if (!DT.isReachableFromEntry(I->getParent()))
-      return getUnknown(UndefValue::get(V->getType()));
+      return getUnknown(PoisonValue::get(V->getType()));
   } else if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
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nikic wrote:
> This change is fine, but I don't think the containsUndef -> containsPoison change makes sense. We can still have SCEVUnknown of UndefValue (from other places), and I believe current containsUndef() callers do want to check for those as well.
I suppose we would need to check for both undef & poison, which is achieved by just checking for UndefVal (because PoisonValue inherits from UndefValue)?


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https://reviews.llvm.org/D128586