--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/MergeableState.java	Mon Mar 31 10:03:32 2014 +0200
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/MergeableState.java	Mon Mar 31 13:45:40 2014 +0200
@@ -61,17 +61,4 @@
     public void afterSplit(AbstractBeginNode node) {
         // empty default implementation
     }
-
-    public static final class EmptyState extends MergeableState<EmptyState> implements Cloneable {
-
-        @Override
-        public EmptyState clone() {
-            return this;
-        }
-
-        @Override
-        public boolean merge(MergeNode merge, List<EmptyState> withStates) {
-            return true;
-        }
-    }
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/graph/StatelessPostOrderNodeIterator.java	Mon Mar 31 13:45:40 2014 +0200
@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2011, 2014, 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 com.oracle.graal.phases.graph;
+
+import java.util.*;
+
+import com.oracle.graal.graph.*;
+import com.oracle.graal.nodes.*;
+
+/**
+ * This iterator implements a reverse post order iteration over the fixed nodes in the graph,
+ * starting at the given fixed node.
+ *
+ * No changes to the fixed nodes are expected during the iteration, they cause undefined behavior.
+ */
+public abstract class StatelessPostOrderNodeIterator {
+
+    private final NodeBitMap visitedEnds;
+    private final Deque<AbstractBeginNode> nodeQueue;
+    private final FixedNode start;
+
+    public StatelessPostOrderNodeIterator(FixedNode start) {
+        visitedEnds = start.graph().createNodeBitMap();
+        nodeQueue = new ArrayDeque<>();
+        this.start = start;
+    }
+
+    public void apply() {
+        FixedNode current = start;
+
+        do {
+            if (current instanceof LoopBeginNode) {
+                loopBegin((LoopBeginNode) current);
+                current = ((LoopBeginNode) current).next();
+                assert current != null;
+            } else if (current instanceof LoopEndNode) {
+                loopEnd((LoopEndNode) current);
+                assert !visitedEnds.isMarked(current);
+                visitedEnds.mark(current);
+                current = nodeQueue.pollFirst();
+            } else if (current instanceof MergeNode) {
+                merge((MergeNode) current);
+                current = ((MergeNode) current).next();
+                assert current != null;
+            } else if (current instanceof FixedWithNextNode) {
+                node(current);
+                current = ((FixedWithNextNode) current).next();
+            } else if (current instanceof EndNode) {
+                end((EndNode) current);
+                queueMerge((EndNode) current);
+                current = nodeQueue.pollFirst();
+            } else if (current instanceof ControlSinkNode) {
+                node(current);
+                current = nodeQueue.pollFirst();
+            } else if (current instanceof ControlSplitNode) {
+                controlSplit((ControlSplitNode) current);
+                for (Node node : current.successors()) {
+                    if (node != null) {
+                        nodeQueue.addFirst((AbstractBeginNode) node);
+                    }
+                }
+                current = nodeQueue.pollFirst();
+            } else {
+                assert false : current;
+            }
+        } while (current != null);
+        finished();
+    }
+
+    private void queueMerge(EndNode end) {
+        assert !visitedEnds.isMarked(end);
+        visitedEnds.mark(end);
+        MergeNode merge = end.merge();
+        boolean endsVisited = true;
+        for (int i = 0; i < merge.forwardEndCount(); i++) {
+            if (!visitedEnds.isMarked(merge.forwardEndAt(i))) {
+                endsVisited = false;
+                break;
+            }
+        }
+        if (endsVisited) {
+            nodeQueue.add(merge);
+        }
+    }
+
+    protected void node(@SuppressWarnings("unused") FixedNode node) {
+        // empty default implementation
+    }
+
+    protected void end(EndNode endNode) {
+        node(endNode);
+    }
+
+    protected void merge(MergeNode merge) {
+        node(merge);
+    }
+
+    protected void loopBegin(LoopBeginNode loopBegin) {
+        node(loopBegin);
+    }
+
+    protected void loopEnd(LoopEndNode loopEnd) {
+        node(loopEnd);
+    }
+
+    protected void controlSplit(ControlSplitNode controlSplit) {
+        node(controlSplit);
+    }
+
+    protected void finished() {
+        // nothing to do
+    }
+}

--- a/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/util/GraphOrder.java	Mon Mar 31 10:03:32 2014 +0200
+++ b/graal/com.oracle.graal.phases/src/com/oracle/graal/phases/util/GraphOrder.java	Mon Mar 31 13:45:40 2014 +0200
@@ -80,7 +80,7 @@
         final ArrayList<Node> nodes = new ArrayList<>();
         final NodeBitMap visited = graph.createNodeBitMap();
 
-        new PostOrderNodeIterator<MergeableState.EmptyState>(graph.start(), new MergeableState.EmptyState()) {
+        new StatelessPostOrderNodeIterator(graph.start()) {
             @Override
             protected void node(FixedNode node) {
                 visitForward(nodes, visited, node, false);