[PATCH] D69038: [InstCombine] Fix miscompile bug in canEvaluateShuffled

[Sanjay Patel via Phabricator via llvm-commits]

spatel accepted this revision.
spatel added a comment.

LGTM with minor fixes as suggested.



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Comment at: llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp:1068
+    case Instruction::SRem:
+      // Avoid introducing integer div/rem by undef to avoid undefined behavior.
+      for (int i = 0, e = Mask.size(); i != e; ++i)
----------------
This comment could provide a better explanation. Something like:
  // Propagating an undefined shuffle mask element to integer
  // div/rem is not allowed because those opcodes can create
  // immediate undefined behavior from an undefined element
  // in an operand. 


Repository:
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  https://reviews.llvm.org/D69038/new/

https://reviews.llvm.org/D69038