--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.phases/src/org/graalvm/compiler/phases/graph/StatelessPostOrderNodeIterator.java	2017-02-15 17:08:29.083467660 -0800
@@ -0,0 +1,141 @@
+/*
+ * 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 org.graalvm.compiler.phases.graph;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeBitMap;
+import org.graalvm.compiler.nodes.AbstractBeginNode;
+import org.graalvm.compiler.nodes.AbstractMergeNode;
+import org.graalvm.compiler.nodes.ControlSinkNode;
+import org.graalvm.compiler.nodes.ControlSplitNode;
+import org.graalvm.compiler.nodes.EndNode;
+import org.graalvm.compiler.nodes.FixedNode;
+import org.graalvm.compiler.nodes.FixedWithNextNode;
+import org.graalvm.compiler.nodes.LoopBeginNode;
+import org.graalvm.compiler.nodes.LoopEndNode;
+
+/**
+ * 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 AbstractMergeNode) {
+                merge((AbstractMergeNode) current);
+                current = ((AbstractMergeNode) 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()) {
+                    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);
+        AbstractMergeNode 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(AbstractMergeNode 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
+    }
+}