Index: include/llvm/ADT/EquivalenceClasses.h
===================================================================
--- include/llvm/ADT/EquivalenceClasses.h
+++ include/llvm/ADT/EquivalenceClasses.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_ADT_EQUIVALENCECLASSES_H
 #define LLVM_ADT_EQUIVALENCECLASSES_H
 
+#include "llvm/ADT/iterator.h"
 #include "llvm/Support/DataTypes.h"
 #include <cassert>
 #include <cstddef>
@@ -150,10 +151,23 @@
     // Only leaders provide anything to iterate over.
     return member_iterator(I->isLeader() ? &*I : nullptr);
   }
+  class leader_iterator;
+  member_iterator member_begin(leader_iterator I) const {
+    return member_iterator(&*I);
+  }
   member_iterator member_end() const {
     return member_iterator(nullptr);
   }
 
+  /// Iterate over the leaders (i.e. the equivalence classes).
+  leader_iterator leader_begin() const {
+    // Only leaders provide anything to iterate over.
+    return leader_iterator(TheMapping.begin(), TheMapping.end());
+  }
+  leader_iterator leader_end() const {
+    return leader_iterator(TheMapping.end(), TheMapping.end());
+  }
+
   /// findValue - Return an iterator to the specified value.  If it does not
   /// exist, end() is returned.
   iterator findValue(const ElemTy &V) const {
@@ -276,6 +290,51 @@
       return Node != RHS.Node;
     }
   };
+
+  class leader_iterator
+      : public iterator_facade_base<leader_iterator, std::forward_iterator_tag,
+                                    const ECValue> {
+    typedef iterator_facade_base<leader_iterator, std::forward_iterator_tag,
+                                 const ECValue> super;
+
+    iterator Iter;
+    iterator End;
+
+    void findLeader() {
+      for (; Iter != End; ++Iter)
+        if (Iter->isLeader())
+          break;
+    }
+
+  public:
+    typedef size_t size_type;
+    typedef typename super::pointer pointer;
+    typedef typename super::reference reference;
+
+    explicit leader_iterator() {}
+    explicit leader_iterator(iterator First, iterator Last)
+        : Iter(First), End(Last) {
+      // Ensure that Iter is pointing at the first leader.
+      findLeader();
+    }
+
+    leader_iterator &operator++() {
+      assert(Iter != End && "++'d off the end of the list!");
+      ++Iter;
+      // If this is not a leader, keep going.
+      findLeader();
+      return *this;
+    }
+
+    reference operator*() const {
+      assert(Iter != End && "Dereferencing end()!");
+      return *Iter;
+    }
+
+    bool operator==(const leader_iterator &RHS) const {
+      return Iter == RHS.Iter;
+    }
+  };
 };
 
 } // End llvm namespace