Index: include/llvm/ADT/MapVector.h
===================================================================
--- include/llvm/ADT/MapVector.h
+++ include/llvm/ADT/MapVector.h
@@ -56,6 +56,12 @@
 
   size_type size() const { return Vector.size(); }
 
+  /// Grow the MapVector so that it can contain at least \p NumEntries items
+  /// before resizing again.
+  void reserve(size_type NumEntries) {
+    Vector.reserve(NumEntries);
+  }
+
   iterator begin() { return Vector.begin(); }
   const_iterator begin() const { return Vector.begin(); }
   iterator end() { return Vector.end(); }
Index: lib/Transforms/Scalar/ADCE.cpp
===================================================================
--- lib/Transforms/Scalar/ADCE.cpp
+++ lib/Transforms/Scalar/ADCE.cpp
@@ -18,6 +18,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
@@ -118,7 +119,8 @@
   PostDominatorTree &PDT;
 
   /// Mapping of blocks to associated information, an element in BlockInfoVec.
-  DenseMap<BasicBlock *, BlockInfoType> BlockInfo;
+  /// Use MapVector to get deterministic iteration order.
+  MapVector<BasicBlock *, BlockInfoType> BlockInfo;
   bool isLive(BasicBlock *BB) { return BlockInfo[BB].Live; }
 
   /// Mapping of instructions to associated information.