[PATCH] D25691: [DAGCombiner] Add vector demanded elements support to computeKnownBits

[Eli Friedman via llvm-commits]

efriedma added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/SelectionDAG.cpp:2555
+      unsigned Idx = ConstEltNo->getZExtValue();
+      assert(Idx < NumSrcElts && "Out of range vector element index");
+      APInt DemandedElt = APInt::getOneBitSet(NumSrcElts, Idx);
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Are your sure it isn't possible to trigger this assertion?  I think DAGCombine will delete an extractelement with an out-of-range index, but you can't depend on that happening before this code runs.


Repository:
  rL LLVM

https://reviews.llvm.org/D25691