[TableGen] Handle ValueType in CodeGenDAGPatterns GetNumNodeResults

A ValueType in a pattern dag is a type cast, and GetNumNodeResults should
handle it (the type cast has only one result).

This comes up, for example, during the type checking of pattern fragments, for
example, AArch64's Neon_combine_2d fragment is:
  dag Operands = (ops node:$Rm, node:$Rn);
  dag Fragment = (v2f64 (concat_vectors (v1f64 node:$Rm), (v1f64 node:$Rn)));

llvm-svn: 198347

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

@@ -1116,6 +1116,9 @@ static unsigned GetNumNodeResults(Record *Operator, CodeGenDAGPatterns &CDP) {
   if (Operator->isSubClassOf("SDNodeXForm"))
     return 1;  // FIXME: Generalize SDNodeXForm
 
+  if (Operator->isSubClassOf("ValueType"))
+    return 1;  // A type-cast of one result.
+
   Operator->dump();
   errs() << "Unhandled node in GetNumNodeResults\n";
   exit(1);