[NFC][LegalizeTypes][VP] Refactor code in SplitRes_Select

[Jimerlife]

Summary

Refactor code in SplitRes_Select

[craig.topper]

I don't understand the motivation for this change. LLVM coding guidelines encourage using early returns.

llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp

547

This assert is exactly opposite the condition of the previous if. It doesn't check anything new.

[Jimerlife]

In D126448#3539383, @craig.topper wrote:

I don't understand the motivation for this change. LLVM coding guidelines encourage using early returns.

Thank for your reminder. Before I don't konw this rule. I will abandon this change.

llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp

else if (Cond.getOpcode() == ISD::SETCC) {
         SplitVecRes_SETCC(Cond.getNode(), CL, CH);
     } else
       std::tie(CL, CH) = DAG.SplitVector(Cond, dl);
   }
 
   if (Opcode != ISD::VP_SELECT && Opcode != ISD::VP_MERGE) {
     Lo = DAG.getNode(Opcode, dl, LL.getValueType(), CL, LL, RL);
     Hi = DAG.getNode(Opcode, dl, LH.getValueType(), CH, LH, RH);
-    return;
-  }
-
+  } else {
+    assert((Opcode == ISD::VP_SELECT || Opcode == ISD::VP_MERGE) &&
+           "Expected VP_SELECT Or VP_MERGE Opcode");
     SDValue EVLLo, EVLHi;
     std::tie(EVLLo, EVLHi) =
         DAG.SplitEVL(N->getOperand(3), N->getValueType(0), dl);
-
     Lo = DAG.getNode(Opcode, dl, LL.getValueType(), CL, LL, RL, EVLLo);
     Hi = DAG.getNode(Opcode, dl, LH.getValueType(), CH, LH, RH, EVLHi);
   }
+}
 
 void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
                                           SDValue &Hi) {
   SDValue LL, LH, RL, RH;
   SDLoc dl(N);
   GetSplitOp(N->getOperand(2), LL, LH);
   GetSplitOp(N->getOperand(3), RL, RH);