Make the Node member of SUnit private, and add accessors.

llvm-svn: 59264
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
index 22791d3..1f45729 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGPrinter.cpp
@@ -438,8 +438,8 @@
                                                       G->DAG) + "\n";
   }
 
-  if (SU->Node)
-    Op += DOTGraphTraits<SelectionDAG*>::getNodeLabel(SU->Node, G->DAG);
+  if (SU->getNode())
+    Op += DOTGraphTraits<SelectionDAG*>::getNodeLabel(SU->getNode(), G->DAG);
   else
     Op += "<CROSS RC COPY>";