diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index d23d4962eb833..897a8a69142a4 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -9126,7 +9126,8 @@ static SDValue combineBinOpToReduce(SDNode *N, SelectionDAG &DAG,
   SDValue ScalarV = Reduce.getOperand(2);
   EVT ScalarVT = ScalarV.getValueType();
   if (ScalarV.getOpcode() == ISD::INSERT_SUBVECTOR &&
-      ScalarV.getOperand(0)->isUndef())
+      ScalarV.getOperand(0)->isUndef() &&
+      isNullConstant(ScalarV.getOperand(2)))
     ScalarV = ScalarV.getOperand(1);
 
   // Make sure that ScalarV is a splat with VL=1.