Add GraphTraits specializations for machine dominators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45333 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineDominators.h

@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/DominatorInternals.h"
+#include "llvm/ADT/GraphTraits.h"
 
 namespace llvm {
 
@@ -182,6 +183,32 @@ public:
   }
 };
 
+//===-------------------------------------
+/// DominatorTree GraphTraits specialization so the DominatorTree can be
+/// iterable by generic graph iterators.
+///
+template <> struct GraphTraits<MachineDomTreeNode *> {
+  typedef MachineDomTreeNode NodeType;
+  typedef NodeType::iterator  ChildIteratorType;
+  
+  static NodeType *getEntryNode(NodeType *N) {
+    return N;
+  }
+  static inline ChildIteratorType child_begin(NodeType* N) {
+    return N->begin();
+  }
+  static inline ChildIteratorType child_end(NodeType* N) {
+    return N->end();
+  }
+};
+
+template <> struct GraphTraits<MachineDominatorTree*>
+  : public GraphTraits<MachineDomTreeNode *> {
+  static NodeType *getEntryNode(MachineDominatorTree *DT) {
+    return DT->getRootNode();
+  }
+};
+
 }
 
 #endif