--- /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/ScopedPostOrderNodeIterator.java	2017-02-15 17:08:28.440439507 -0800
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2013, 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.graph.iterators.NodeIterable;
+import org.graalvm.compiler.nodes.AbstractEndNode;
+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.Invoke;
+import org.graalvm.compiler.nodes.LoopBeginNode;
+import org.graalvm.compiler.nodes.LoopEndNode;
+import org.graalvm.compiler.nodes.LoopExitNode;
+import org.graalvm.compiler.nodes.StructuredGraph;
+
+public abstract class ScopedPostOrderNodeIterator {
+
+    private final Deque<FixedNode> nodeQueue;
+    private final NodeBitMap queuedNodes;
+    private final Deque<FixedNode> scopes;
+
+    protected FixedNode currentScopeStart;
+
+    public ScopedPostOrderNodeIterator(StructuredGraph graph) {
+        this.queuedNodes = graph.createNodeBitMap();
+        this.nodeQueue = new ArrayDeque<>();
+        this.scopes = getScopes(graph);
+    }
+
+    public void apply() {
+        while (!scopes.isEmpty()) {
+            queuedNodes.clearAll();
+            this.currentScopeStart = scopes.pop();
+            initializeScope();
+            processScope();
+        }
+    }
+
+    public void processScope() {
+        FixedNode current;
+        queue(currentScopeStart);
+
+        while ((current = nextQueuedNode()) != null) {
+            assert current.isAlive();
+
+            if (current instanceof Invoke) {
+                invoke((Invoke) current);
+                queueSuccessors(current);
+            } else if (current instanceof LoopBeginNode) {
+                queueLoopBeginSuccessors((LoopBeginNode) current);
+            } else if (current instanceof LoopExitNode) {
+                queueLoopExitSuccessors((LoopExitNode) current);
+            } else if (current instanceof LoopEndNode) {
+                // nothing todo
+            } else if (current instanceof AbstractMergeNode) {
+                queueSuccessors(current);
+            } else if (current instanceof FixedWithNextNode) {
+                queueSuccessors(current);
+            } else if (current instanceof EndNode) {
+                queueMerge((EndNode) current);
+            } else if (current instanceof ControlSinkNode) {
+                // nothing todo
+            } else if (current instanceof ControlSplitNode) {
+                queueSuccessors(current);
+            } else {
+                assert false : current;
+            }
+        }
+    }
+
+    protected void queueLoopBeginSuccessors(LoopBeginNode node) {
+        if (currentScopeStart == node) {
+            queue(node.next());
+        } else if (currentScopeStart instanceof LoopBeginNode) {
+            // so we are currently processing loop A and found another loop B
+            // -> queue all loop exits of B except those that also exit loop A
+            for (LoopExitNode loopExit : node.loopExits()) {
+                if (!((LoopBeginNode) currentScopeStart).loopExits().contains(loopExit)) {
+                    queue(loopExit);
+                }
+            }
+        } else {
+            queue(node.loopExits());
+        }
+    }
+
+    protected void queueLoopExitSuccessors(LoopExitNode node) {
+        if (!(currentScopeStart instanceof LoopBeginNode) || !((LoopBeginNode) currentScopeStart).loopExits().contains(node)) {
+            queueSuccessors(node);
+        }
+    }
+
+    protected Deque<FixedNode> getScopes(StructuredGraph graph) {
+        Deque<FixedNode> result = new ArrayDeque<>();
+        result.push(graph.start());
+        for (LoopBeginNode loopBegin : graph.getNodes(LoopBeginNode.TYPE)) {
+            result.push(loopBegin);
+        }
+        return result;
+    }
+
+    private void queueSuccessors(FixedNode x) {
+        queue(x.successors());
+    }
+
+    private void queue(NodeIterable<? extends Node> iter) {
+        for (Node node : iter) {
+            queue(node);
+        }
+    }
+
+    private void queue(Node node) {
+        if (node != null && !queuedNodes.isMarked(node)) {
+            queuedNodes.mark(node);
+            nodeQueue.addFirst((FixedNode) node);
+        }
+    }
+
+    private FixedNode nextQueuedNode() {
+        if (nodeQueue.isEmpty()) {
+            return null;
+        }
+
+        FixedNode result = nodeQueue.removeFirst();
+        assert queuedNodes.isMarked(result);
+        return result;
+    }
+
+    private void queueMerge(AbstractEndNode end) {
+        AbstractMergeNode merge = end.merge();
+        if (!queuedNodes.isMarked(merge) && visitedAllEnds(merge)) {
+            queue(merge);
+        }
+    }
+
+    private boolean visitedAllEnds(AbstractMergeNode merge) {
+        for (int i = 0; i < merge.forwardEndCount(); i++) {
+            if (!queuedNodes.isMarked(merge.forwardEndAt(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    protected abstract void initializeScope();
+
+    protected abstract void invoke(Invoke invoke);
+}