1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index bd69055..9072697 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -290,6 +290,10 @@ Value *llvm::findScalarElement(Value *V, unsigned EltNo) {
     if (EltNo == IIElt)
       return III->getOperand(1);
 
+    // Guard against infinite loop on malformed, unreachable IR.
+    if (III == III->getOperand(0))
+      return nullptr;
+
     // Otherwise, the insertelement doesn't modify the value, recurse on its
     // vector input.
     return findScalarElement(III->getOperand(0), EltNo);