[CodeGen] Fix a warning in DAGTypeLegalizer::SetSplitVector

[david-arm]

Summary

This fixes up one warning in the test:

sve-sext-zext.ll

[c-rhodes]

LGTM

llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp

void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
   Hi = getSDValue(Entry.second);
   assert(Lo.getNode() && "Operand isn't split");
   ;
 }
 
 void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
                                       SDValue Hi) {
   assert(Lo.getValueType().getVectorElementType() ==
              Op.getValueType().getVectorElementType() &&
-         2*Lo.getValueType().getVectorNumElements() ==
-         Op.getValueType().getVectorNumElements() &&
+         Lo.getValueType().getVectorElementCount() * 2 ==
+             Op.getValueType().getVectorElementCount() &&
          Hi.getValueType() == Lo.getValueType() &&
          "Invalid type for split vector");
   // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
   AnalyzeNewValue(Lo);
   AnalyzeNewValue(Hi);
 
   // Remember that this is the result of the node.
   std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)];