[PATCH] D78765: [TRE] Fix bug in handling of switch statements

[Layton Kifer via Phabricator via llvm-commits]

laytonio created this revision.
laytonio added reviewers: nlewycky, lattner, Carrot, efriedma.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

Switch values are only dynamic constant if the return can only be reached from one case. The current implementation only checks that its not the default but not if other cases can result in the same jump.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D78765

Files:
  llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp


Index: llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -385,7 +385,7 @@
   if (BasicBlock *UniquePred = RI->getParent()->getUniquePredecessor())
     if (SwitchInst *SI = dyn_cast<SwitchInst>(UniquePred->getTerminator()))
       if (SI->getCondition() == V)
-        return SI->getDefaultDest() != RI->getParent();
+        return SI->findCaseDest(RI->getParent()) != nullptr;
 
   // Not a constant or immutable argument, we can't safely transform.
   return false;


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