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diff --git a/contrib/llvm/lib/Transforms/Instrumentation/MaximumSpanningTree.h b/contrib/llvm/lib/Transforms/Instrumentation/MaximumSpanningTree.h
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+++ b/contrib/llvm/lib/Transforms/Instrumentation/MaximumSpanningTree.h
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+//===- llvm/Analysis/MaximumSpanningTree.h - Interface ----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This module privides means for calculating a maximum spanning tree for a
+// given set of weighted edges. The type parameter T is the type of a node.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_MAXIMUMSPANNINGTREE_H
+#define LLVM_ANALYSIS_MAXIMUMSPANNINGTREE_H
+
+#include "llvm/BasicBlock.h"
+#include "llvm/ADT/EquivalenceClasses.h"
+#include <vector>
+#include <algorithm>
+
+namespace llvm {
+
+  /// MaximumSpanningTree - A MST implementation.
+  /// The type parameter T determines the type of the nodes of the graph.
+  template <typename T>
+  class MaximumSpanningTree {
+
+    // A comparing class for comparing weighted edges.
+    template <typename CT>
+    struct EdgeWeightCompare {
+      bool operator()(typename MaximumSpanningTree<CT>::EdgeWeight X, 
+                      typename MaximumSpanningTree<CT>::EdgeWeight Y) const {
+        if (X.second > Y.second) return true;
+        if (X.second < Y.second) return false;
+        if (const BasicBlock *BBX = dyn_cast<BasicBlock>(X.first.first)) {
+          if (const BasicBlock *BBY = dyn_cast<BasicBlock>(Y.first.first)) {
+            if (BBX->size() > BBY->size()) return true;
+            if (BBX->size() < BBY->size()) return false;
+          }
+        }
+        if (const BasicBlock *BBX = dyn_cast<BasicBlock>(X.first.second)) {
+          if (const BasicBlock *BBY = dyn_cast<BasicBlock>(Y.first.second)) {
+            if (BBX->size() > BBY->size()) return true;
+            if (BBX->size() < BBY->size()) return false;
+          }
+        }
+        return false;
+      }
+    };
+
+  public:
+    typedef std::pair<const T*, const T*> Edge;
+    typedef std::pair<Edge, double> EdgeWeight;
+    typedef std::vector<EdgeWeight> EdgeWeights;
+  protected:
+    typedef std::vector<Edge> MaxSpanTree;
+
+    MaxSpanTree MST;
+
+  public:
+    static char ID; // Class identification, replacement for typeinfo
+
+    /// MaximumSpanningTree() - Takes a vector of weighted edges and returns a
+    /// spanning tree.
+    MaximumSpanningTree(EdgeWeights &EdgeVector) {
+
+      std::stable_sort(EdgeVector.begin(), EdgeVector.end(), EdgeWeightCompare<T>());
+
+      // Create spanning tree, Forest contains a special data structure
+      // that makes checking if two nodes are already in a common (sub-)tree
+      // fast and cheap.
+      EquivalenceClasses<const T*> Forest;
+      for (typename EdgeWeights::iterator EWi = EdgeVector.begin(),
+           EWe = EdgeVector.end(); EWi != EWe; ++EWi) {
+        Edge e = (*EWi).first;
+
+        Forest.insert(e.first);
+        Forest.insert(e.second);
+      }
+
+      // Iterate over the sorted edges, biggest first.
+      for (typename EdgeWeights::iterator EWi = EdgeVector.begin(),
+           EWe = EdgeVector.end(); EWi != EWe; ++EWi) {
+        Edge e = (*EWi).first;
+
+        if (Forest.findLeader(e.first) != Forest.findLeader(e.second)) {
+          Forest.unionSets(e.first, e.second);
+          // So we know now that the edge is not already in a subtree, so we push
+          // the edge to the MST.
+          MST.push_back(e);
+        }
+      }
+    }
+
+    typename MaxSpanTree::iterator begin() {
+      return MST.begin();
+    }
+
+    typename MaxSpanTree::iterator end() {
+      return MST.end();
+    }
+  };
+
+} // End llvm namespace
+
+#endif