Index: include/llvm/Support/GenericDomTreeConstruction.h
===================================================================
--- include/llvm/Support/GenericDomTreeConstruction.h
+++ include/llvm/Support/GenericDomTreeConstruction.h
@@ -25,82 +25,32 @@
 #ifndef LLVM_SUPPORT_GENERICDOMTREECONSTRUCTION_H
 #define LLVM_SUPPORT_GENERICDOMTREECONSTRUCTION_H
 
+#include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/GenericDomTree.h"
 
 namespace llvm {
 
-template<class GraphT>
-unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType>& DT,
-                 typename GraphT::NodeType* V, unsigned N) {
-  // This is more understandable as a recursive algorithm, but we can't use the
-  // recursive algorithm due to stack depth issues.  Keep it here for
-  // documentation purposes.
-#if 0
-  InfoRec &VInfo = DT.Info[DT.Roots[i]];
-  VInfo.DFSNum = VInfo.Semi = ++N;
-  VInfo.Label = V;
-
-  Vertex.push_back(V);        // Vertex[n] = V;
-
-  for (succ_iterator SI = succ_begin(V), E = succ_end(V); SI != E; ++SI) {
-    InfoRec &SuccVInfo = DT.Info[*SI];
-    if (SuccVInfo.Semi == 0) {
-      SuccVInfo.Parent = V;
-      N = DTDFSPass(DT, *SI, N);
-    }
-  }
-#else
+template <class GraphT>
+unsigned DFSPass(DominatorTreeBase<typename GraphT::NodeType> &DT,
+                 typename GraphT::NodeType *V, unsigned N) {
   bool IsChildOfArtificialExit = (N != 0);
-
-  SmallVector<std::pair<typename GraphT::NodeType*,
-                        typename GraphT::ChildIteratorType>, 32> Worklist;
-  Worklist.push_back(std::make_pair(V, GraphT::child_begin(V)));
-  while (!Worklist.empty()) {
-    typename GraphT::NodeType* BB = Worklist.back().first;
-    typename GraphT::ChildIteratorType NextSucc = Worklist.back().second;
-
+  for (auto I = df_begin(V), E = df_end(V); I != E; ++I) {
+    typename GraphT::NodeType *BB = *I;
     typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &BBInfo =
-                                                                    DT.Info[BB];
-
-    // First time we visited this BB?
-    if (NextSucc == GraphT::child_begin(BB)) {
-      BBInfo.DFSNum = BBInfo.Semi = ++N;
-      BBInfo.Label = BB;
-
-      DT.Vertex.push_back(BB);       // Vertex[n] = V;
-
-      if (IsChildOfArtificialExit)
-        BBInfo.Parent = 1;
-
-      IsChildOfArtificialExit = false;
-    }
-
-    // store the DFS number of the current BB - the reference to BBInfo might
-    // get invalidated when processing the successors.
-    unsigned BBDFSNum = BBInfo.DFSNum;
+        DT.Info[BB];
+    BBInfo.DFSNum = BBInfo.Semi = ++N;
+    BBInfo.Label = BB;
+    // Set the parent to the top of the visited stack
+    BBInfo.Parent = DT.Info[I.getPath(I.getPathLength() - 1)].DFSNum;
+    DT.Vertex.push_back(BB); // Vertex[n] = V;
 
-    // If we are done with this block, remove it from the worklist.
-    if (NextSucc == GraphT::child_end(BB)) {
-      Worklist.pop_back();
-      continue;
-    }
+    if (IsChildOfArtificialExit)
+      BBInfo.Parent = 1;
 
-    // Increment the successor number for the next time we get to it.
-    ++Worklist.back().second;
-    
-    // Visit the successor next, if it isn't already visited.
-    typename GraphT::NodeType* Succ = *NextSucc;
-
-    typename DominatorTreeBase<typename GraphT::NodeType>::InfoRec &SuccVInfo =
-                                                                  DT.Info[Succ];
-    if (SuccVInfo.Semi == 0) {
-      SuccVInfo.Parent = BBDFSNum;
-      Worklist.push_back(std::make_pair(Succ, GraphT::child_begin(Succ)));
-    }
+    IsChildOfArtificialExit = false;
   }
-#endif
-    return N;
+  return N;
 }
 
 template<class GraphT>