[PATCH] D75977: [JumpThreading] Fix PR44611

[Kazu Hirata via Phabricator via llvm-commits]

kazu added a comment.

Sorry, the infinite recursion seems to come from EvaluateOnPredecessorEdge, a function that I recently added to support jump threading across two basic blocks.  EvaluateOnPredecessorEdge does not have a guard against infinite recursion while its close cousin ComputeValueKnownInPredecessors does.

The best thing to do is to get rid of the code duplication I introduced, namely EvaluateOnPredecessorEdge, but for now we can detect infinite recursion by maintaining RecursionSet much like ComputeValueKnownInPredecessors.  Alternatively, we could pass a recursion depth and stop recursion when we reach a certain limit.  We have a limit on the number of LLVM IR statements we duplicate, so we could use that as a starting point.

Anyway, let me try to come up with something.


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https://reviews.llvm.org/D75977