Make the SelectionDAG graph printer use SDNode::PersistentId labels.

r248010 changed the -debug output to use short ids, but did not
similarly modify the graph printer. Change to be consistent, for ease of
cross-reference.

llvm-svn: 251465
diff --git a/llvm/lib/CodeGen/ScheduleDAGPrinter.cpp b/llvm/lib/CodeGen/ScheduleDAGPrinter.cpp
index b2e4617..1150d26 100644
--- a/llvm/lib/CodeGen/ScheduleDAGPrinter.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGPrinter.cpp
@@ -43,9 +43,12 @@
       return (Node->NumPreds > 10 || Node->NumSuccs > 10);
     }
 
-    static bool hasNodeAddressLabel(const SUnit *Node,
-                                    const ScheduleDAG *Graph) {
-      return true;
+    static std::string getNodeIdentifierLabel(const SUnit *Node,
+                                              const ScheduleDAG *Graph) {
+      std::string R;
+      raw_string_ostream OS(R);
+      OS << static_cast<const void *>(Node);
+      return R;
     }
 
     /// If you want to override the dot attributes printed for a particular