[X86] Use isNullConstant helper. NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338516 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b6df0a0..981bb17 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -37928,8 +37928,7 @@ static SDValue combineFMA(SDNode *N, SelectionDAG &DAG,
     // Look through extract_vector_elts. If it comes from an FNEG, create a
     // new extract from the FNEG input.
     if (V.getOpcode() == ISD::EXTRACT_VECTOR_ELT &&
-        isa<ConstantSDNode>(V.getOperand(1)) &&
-        cast<ConstantSDNode>(V.getOperand(1))->getZExtValue() == 0) {
+        isNullConstant(V.getOperand(1))) {
       if (SDValue NegVal = isFNEG(V.getOperand(0).getNode())) {
         NegVal = DAG.getBitcast(V.getOperand(0).getValueType(), NegVal);
         V = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SDLoc(V), V.getValueType(),