Index: include/llvm/Support/GenericDomTreeConstruction.h
===================================================================
--- include/llvm/Support/GenericDomTreeConstruction.h
+++ include/llvm/Support/GenericDomTreeConstruction.h
@@ -76,118 +76,108 @@
                 llvm::make_unique<DomTreeNodeBase<NodeT>>(BB, IDomNode)))
         .get();
   }
-};
-}  // namespace detail
 
-// External storage for depth first iterator that reuses the info lookup map
-// domtree already has.  We don't have a set, but a map instead, so we are
-// converting the one argument insert calls.
-template <class NodeRef, class InfoType> struct df_iterator_dom_storage {
-public:
-  using BaseSet = DenseMap<NodeRef, InfoType>;
-  df_iterator_dom_storage(BaseSet &Storage) : Storage(Storage) {}
-
-  using iterator = typename BaseSet::iterator;
-  std::pair<iterator, bool> insert(NodeRef N) {
-    return Storage.insert({N, InfoType()});
-  }
-  void completed(NodeRef) {}
+  // External storage for depth first iterator that reuses the info lookup map
+  // SemiNCAInfo already has. We don't have a set, but a map instead, so we are
+  // converting the one argument insert calls.
+  struct df_iterator_dom_storage {
+   public:
+    using BaseSet = decltype(NodeToInfo);
+    df_iterator_dom_storage(BaseSet &Storage) : Storage(Storage) {}
+
+    using iterator = typename BaseSet::iterator;
+    std::pair<iterator, bool> insert(NodePtr N) {
+      return Storage.insert({N, InfoRec()});
+    }
+    void completed(NodePtr) {}
 
-private:
-  BaseSet &Storage;
-};
+   private:
+    BaseSet &Storage;
+  };
 
-template <class NodePtr,
-          class NodeT = typename std::remove_pointer<NodePtr>::type>
-unsigned ReverseDFSPass(NodePtr V, detail::SemiNCAInfo<NodeT> &SNCA,
-                        unsigned N) {
-  using SNCAInfoTy = detail::SemiNCAInfo<NodeT>;
-  df_iterator_dom_storage<NodePtr, typename SNCAInfoTy::InfoRec> DFStorage(
-      SNCA.NodeToInfo);
-
-  bool IsChildOfArtificialExit = (N != 0);
-  for (auto I = idf_ext_begin(V, DFStorage), E = idf_ext_end(V, DFStorage);
-       I != E; ++I) {
-    NodePtr BB = *I;
-    auto &BBInfo = SNCA.NodeToInfo[BB];
-    BBInfo.DFSNum = BBInfo.Semi = ++N;
-    BBInfo.Label = BB;
-    // Set the parent to the top of the visited stack.  The stack includes us,
-    // and is 1 based, so we subtract to account for both of these.
-    if (I.getPathLength() > 1)
-      BBInfo.Parent = SNCA.NodeToInfo[I.getPath(I.getPathLength() - 2)].DFSNum;
-    SNCA.NumToNode.push_back(BB);  // NumToNode[n] = V;
+  df_iterator_dom_storage getStorage() { return {NodeToInfo}; }
+
+  unsigned runReverseDFS(NodePtr V, unsigned N) {
+    auto DFStorage = getStorage();
+
+    bool IsChildOfArtificialExit = (N != 0);
+    for (auto I = idf_ext_begin(V, DFStorage), E = idf_ext_end(V, DFStorage);
+         I != E; ++I) {
+      NodePtr BB = *I;
+      auto &BBInfo = NodeToInfo[BB];
+      BBInfo.DFSNum = BBInfo.Semi = ++N;
+      BBInfo.Label = BB;
+      // Set the parent to the top of the visited stack.  The stack includes us,
+      // and is 1 based, so we subtract to account for both of these.
+      if (I.getPathLength() > 1)
+        BBInfo.Parent = NodeToInfo[I.getPath(I.getPathLength() - 2)].DFSNum;
+      NumToNode.push_back(BB);  // NumToNode[n] = V;
 
-    if (IsChildOfArtificialExit)
-      BBInfo.Parent = 1;
+      if (IsChildOfArtificialExit)
+        BBInfo.Parent = 1;
 
-    IsChildOfArtificialExit = false;
+      IsChildOfArtificialExit = false;
+    }
+    return N;
   }
-  return N;
-}
 
-template <class NodePtr,
-          class NodeT = typename std::remove_pointer<NodePtr>::type>
-unsigned DFSPass(NodePtr V, detail::SemiNCAInfo<NodeT> &SNCA, unsigned N) {
-  using SNCAInfoTy = detail::SemiNCAInfo<NodeT>;
-  df_iterator_dom_storage<NodePtr, typename SNCAInfoTy::InfoRec> DFStorage(
-      SNCA.NodeToInfo);
-
-  for (auto I = df_ext_begin(V, DFStorage), E = df_ext_end(V, DFStorage);
-       I != E; ++I) {
-    NodePtr BB = *I;
-    auto &BBInfo = SNCA.NodeToInfo[BB];
-    BBInfo.DFSNum = BBInfo.Semi = ++N;
-    BBInfo.Label = BB;
-    // Set the parent to the top of the visited stack.  The stack includes us,
-    // and is 1 based, so we subtract to account for both of these.
-    if (I.getPathLength() > 1)
-      BBInfo.Parent = SNCA.NodeToInfo[I.getPath(I.getPathLength() - 2)].DFSNum;
-    SNCA.NumToNode.push_back(BB);  // NumToNode[n] = V;
+  unsigned runDFS(NodePtr V, unsigned N) {
+    auto DFStorage = getStorage();
+
+    for (auto I = df_ext_begin(V, DFStorage), E = df_ext_end(V, DFStorage);
+         I != E; ++I) {
+      NodePtr BB = *I;
+      auto &BBInfo = NodeToInfo[BB];
+      BBInfo.DFSNum = BBInfo.Semi = ++N;
+      BBInfo.Label = BB;
+      // Set the parent to the top of the visited stack.  The stack includes us,
+      // and is 1 based, so we subtract to account for both of these.
+      if (I.getPathLength() > 1)
+        BBInfo.Parent = NodeToInfo[I.getPath(I.getPathLength() - 2)].DFSNum;
+      NumToNode.push_back(BB);  // NumToNode[n] = V;
+    }
+    return N;
   }
-  return N;
-}
 
-template <class NodePtr,
-          class NodeT = typename std::remove_pointer<NodePtr>::type>
-NodePtr Eval(NodePtr VIn, detail::SemiNCAInfo<NodeT> &SNCA,
-             unsigned LastLinked) {
-  auto &VInInfo = SNCA.NodeToInfo[VIn];
-  if (VInInfo.DFSNum < LastLinked)
-    return VIn;
+  NodePtr eval(NodePtr VIn, unsigned LastLinked) {
+    auto &VInInfo = NodeToInfo[VIn];
+    if (VInInfo.DFSNum < LastLinked)
+      return VIn;
 
-  SmallVector<NodePtr, 32> Work;
-  SmallPtrSet<NodePtr, 32> Visited;
+    SmallVector<NodePtr, 32> Work;
+    SmallPtrSet<NodePtr, 32> Visited;
 
-  if (VInInfo.Parent >= LastLinked)
-    Work.push_back(VIn);
+    if (VInInfo.Parent >= LastLinked)
+      Work.push_back(VIn);
 
-  while (!Work.empty()) {
-    NodePtr V = Work.back();
-    auto &VInfo = SNCA.NodeToInfo[V];
-    NodePtr VAncestor = SNCA.NumToNode[VInfo.Parent];
+    while (!Work.empty()) {
+      NodePtr V = Work.back();
+      auto &VInfo = NodeToInfo[V];
+      NodePtr VAncestor = NumToNode[VInfo.Parent];
 
-    // Process Ancestor first
-    if (Visited.insert(VAncestor).second && VInfo.Parent >= LastLinked) {
-      Work.push_back(VAncestor);
-      continue;
+      // Process Ancestor first
+      if (Visited.insert(VAncestor).second && VInfo.Parent >= LastLinked) {
+        Work.push_back(VAncestor);
+        continue;
+      }
+      Work.pop_back();
+
+      // Update VInfo based on Ancestor info
+      if (VInfo.Parent < LastLinked)
+        continue;
+
+      auto &VAInfo = NodeToInfo[VAncestor];
+      NodePtr VAncestorLabel = VAInfo.Label;
+      NodePtr VLabel = VInfo.Label;
+      if (NodeToInfo[VAncestorLabel].Semi < NodeToInfo[VLabel].Semi)
+        VInfo.Label = VAncestorLabel;
+      VInfo.Parent = VAInfo.Parent;
     }
-    Work.pop_back();
-
-    // Update VInfo based on Ancestor info
-    if (VInfo.Parent < LastLinked)
-      continue;
-
-    auto &VAInfo = SNCA.NodeToInfo[VAncestor];
-    NodePtr VAncestorLabel = VAInfo.Label;
-    NodePtr VLabel = VInfo.Label;
-    if (SNCA.NodeToInfo[VAncestorLabel].Semi < SNCA.NodeToInfo[VLabel].Semi)
-      VInfo.Label = VAncestorLabel;
-    VInfo.Parent = VAInfo.Parent;
-  }
 
-  return VInInfo.Label;
-}
+    return VInInfo.Label;
+  }
+};
+}  // namespace detail
 
 template <class FuncT, class NodeT>
 void Calculate(DominatorTreeBaseByGraphTraits<GraphTraits<NodeT>> &DT,
@@ -216,9 +206,9 @@
   if (DT.isPostDominator()){
     for (unsigned i = 0, e = static_cast<unsigned>(DT.Roots.size());
          i != e; ++i)
-      N = ReverseDFSPass<NodePtr>(DT.Roots[i], SNCA, N);
+      N = SNCA.runReverseDFS(DT.Roots[i], N);
   } else {
-    N = DFSPass<NodePtr>(DT.Roots[0], SNCA, N);
+    N = SNCA.runDFS(DT.Roots[0], N);
   }
 
   // It might be that some blocks did not get a DFS number (e.g., blocks of
@@ -241,7 +231,7 @@
     WInfo.Semi = WInfo.Parent;
     for (const auto &N : inverse_children<NodeT>(W))
       if (SNCA.NodeToInfo.count(N)) {  // Only if this predecessor is reachable!
-        unsigned SemiU = SNCA.NodeToInfo[Eval<NodePtr>(N, SNCA, i + 1)].Semi;
+        unsigned SemiU = SNCA.NodeToInfo[SNCA.eval(N, i + 1)].Semi;
         if (SemiU < WInfo.Semi)
           WInfo.Semi = SemiU;
       }