Address review comment

Author: preames

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -11894,23 +11894,17 @@ SDValue TargetLowering::expandPartialReduceMLA(SDNode *N,
   EVT ExtMulOpVT =
       EVT::getVectorVT(*DAG.getContext(), AccVT.getVectorElementType(),
                        MulOpVT.getVectorElementCount());
+
+  unsigned ExtOpcLHS = N->getOpcode() == ISD::PARTIAL_REDUCE_UMLA
+                      ? ISD::ZERO_EXTEND
+                      : ISD::SIGN_EXTEND;
+  unsigned ExtOpcRHS = N->getOpcode() == ISD::PARTIAL_REDUCE_SMLA
+                      ? ISD::SIGN_EXTEND
+                      : ISD::ZERO_EXTEND;
+
   if (ExtMulOpVT != MulOpVT) {
-    switch (N->getOpcode()) {
-    case ISD::PARTIAL_REDUCE_SMLA:
-      MulLHS = DAG.getNode(ISD::SIGN_EXTEND, DL, ExtMulOpVT, MulLHS);
-      MulRHS = DAG.getNode(ISD::SIGN_EXTEND, DL, ExtMulOpVT, MulRHS);
-      break;
-    case ISD::PARTIAL_REDUCE_UMLA:
-      MulLHS = DAG.getNode(ISD::ZERO_EXTEND, DL, ExtMulOpVT, MulLHS);
-      MulRHS = DAG.getNode(ISD::ZERO_EXTEND, DL, ExtMulOpVT, MulRHS);
-      break;
-    case ISD::PARTIAL_REDUCE_SUMLA:
-      MulLHS = DAG.getNode(ISD::SIGN_EXTEND, DL, ExtMulOpVT, MulLHS);
-      MulRHS = DAG.getNode(ISD::ZERO_EXTEND, DL, ExtMulOpVT, MulRHS);
-      break;
-    default:
-      llvm_unreachable("unexpected opcode");
-    }
+    MulLHS = DAG.getNode(ExtOpcLHS, DL, ExtMulOpVT, MulLHS);
+    MulRHS = DAG.getNode(ExtOpcRHS, DL, ExtMulOpVT, MulRHS);
   }
   SDValue Input = MulLHS;
   APInt ConstantOne;