Add a (disabled by default) way to view the ID of a node.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42978 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp

@@ -173,6 +173,10 @@ std::string DOTGraphTraits<SelectionDAG*>::getNodeLabel(const SDNode *Node,
     Op += ST->getIndexedModeName(ST->getAddressingMode());
   }
 
+#if 0
+  Op += " Id=" + itostr(Node->getNodeId());
+#endif
+  
   return Op;
 }