[X86] Fix a crash that can occur in combineExtractVectorElt due to not checking the width of a ConstantSDNode before calling getConstantOperandVal.

llvm-svn: 323614

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 4b1efab9430..a0ed2934fc4 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -31238,8 +31238,9 @@ static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG,
       isa<ConstantSDNode>(EltIdx) &&
       isa<ConstantSDNode>(InputVector.getOperand(0))) {
     uint64_t ExtractedElt = N->getConstantOperandVal(1);
-    uint64_t InputValue = InputVector.getConstantOperandVal(0);
-    uint64_t Res = (InputValue >> ExtractedElt) & 1;
+    auto *InputC = cast<ConstantSDNode>(InputVector.getOperand(0));
+    const APInt &InputValue = InputC->getAPIntValue();
+    uint64_t Res = InputValue[ExtractedElt];
     return DAG.getConstant(Res, dl, MVT::i1);
   }