[InstSimplify] Check for in range extraction index before calling APInt::getZExtValue()
Reduced from oss-fuzz #4768 test case
llvm-svn: 321454
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 3ce1281..fac6a91 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -3897,8 +3897,9 @@
// If extracting a specified index from the vector, see if we can recursively
// find a previously computed scalar that was inserted into the vector.
if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
- if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
- return Elt;
+ if (IdxC->getValue().ule(Vec->getType()->getVectorNumElements()))
+ if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
+ return Elt;
// An undef extract index can be arbitrarily chosen to be an out-of-range
// index value, which would result in the instruction being undef.