--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/NodeNodeMap.java	2016-12-09 00:48:28.050612394 -0800
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2011, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.graalvm.compiler.graph;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public final class NodeNodeMap extends NodeMap<Node> implements Map<Node, Node> {
+
+    public NodeNodeMap(Graph graph) {
+        super(graph);
+    }
+
+    public NodeNodeMap(NodeNodeMap copyFrom) {
+        super(copyFrom);
+    }
+
+    @Override
+    public Node get(Object key) {
+        return super.get((Node) key);
+    }
+
+    @Override
+    public Node put(Node key, Node value) {
+        Node oldValue = super.get(key);
+        super.set(key, value);
+        return oldValue;
+    }
+
+    @Override
+    public Node remove(Object key) {
+        throw new UnsupportedOperationException("Cannot remove keys from this map");
+    }
+
+    @Override
+    public void putAll(Map<? extends Node, ? extends Node> m) {
+        for (Entry<? extends Node, ? extends Node> entry : m.entrySet()) {
+            put(entry.getKey(), entry.getValue());
+        }
+    }
+
+    @Override
+    public Set<Node> keySet() {
+        HashSet<Node> entries = new HashSet<>();
+        for (int i = 0; i < values.length; ++i) {
+            Object v = values[i];
+            if (v != null) {
+                Node key = getKey(i);
+                if (key != null) {
+                    entries.add(key);
+                }
+            }
+        }
+        /*
+         * The normal contract for entrySet is that modifications of the set are reflected in the
+         * underlying data structure. For simplicity don't allow that but complain if someone tries
+         * to use it that way.
+         */
+        return Collections.unmodifiableSet(entries);
+    }
+
+    @Override
+    public Collection<Node> values() {
+        ArrayList<Node> result = new ArrayList<>(this.size());
+        for (int i = 0; i < values.length; ++i) {
+            Object v = values[i];
+            if (v != null) {
+                result.add((Node) v);
+            }
+        }
+        return result;
+    }
+
+    @Override
+    public Set<Map.Entry<Node, Node>> entrySet() {
+        HashSet<Map.Entry<Node, Node>> entries = new HashSet<>();
+        for (Map.Entry<Node, Node> entry : entries()) {
+            entries.add(entry);
+        }
+        /*
+         * The normal contract for entrySet is that modifications of the set are reflected in the
+         * underlying data structure. For simplicity don't allow that but complain if someone tries
+         * to use it that way.
+         */
+        return Collections.unmodifiableSet(entries);
+    }
+}