[WebAssembly] Comment out a switch block in ISelDAGToDAG

[aheejin]

Summary

Fixes PR37977.

[RKSimon]

LGTM with one minor

lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp

77–80

Probably not worth keeping the VT here? Its easy enough to add back if you need it - I think you're mainly interested in showing how to use the switch statement.

[aheejin]

• Removed VT

lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp

 
 void WebAssemblyDAGToDAGISel::Select(SDNode *Node) {
   // If we have a custom node, we already have selected!
   if (Node->isMachineOpcode()) {
     LLVM_DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
     Node->setNodeId(-1);
     return;
   }
 
-  // Few custom selection stuff.
-  EVT VT = Node->getValueType(0);
-
+  // Few custom selection stuff. If we need WebAssembly-specific selection,
+  // uncomment this block add corresponding case statements.
+  /*
   switch (Node->getOpcode()) {
   default:
     break;
-    // If we need WebAssembly-specific selection, it would go here.
-    (void)VT;
   }
+  */
 
   // Select the default instruction.
   SelectCode(Node);
 }
 
 bool WebAssemblyDAGToDAGISel::SelectInlineAsmMemoryOperand(
     const SDValue &Op, unsigned ConstraintID, std::vector<SDValue> &OutOps) {
   switch (ConstraintID) {