--- /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/FixedNodeProbabilityCache.java	2017-02-15 17:08:26.181340600 -0800
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 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.Map;
+import java.util.function.ToDoubleFunction;
+
+import org.graalvm.compiler.debug.Debug;
+import org.graalvm.compiler.debug.DebugCounter;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeInputList;
+import org.graalvm.compiler.nodes.AbstractBeginNode;
+import org.graalvm.compiler.nodes.AbstractEndNode;
+import org.graalvm.compiler.nodes.AbstractMergeNode;
+import org.graalvm.compiler.nodes.ControlSplitNode;
+import org.graalvm.compiler.nodes.EndNode;
+import org.graalvm.compiler.nodes.FixedNode;
+import org.graalvm.compiler.nodes.LoopBeginNode;
+import org.graalvm.compiler.nodes.StartNode;
+
+/**
+ * Compute probabilities for fixed nodes on the fly and cache them at {@link AbstractBeginNode}s.
+ */
+public class FixedNodeProbabilityCache implements ToDoubleFunction<FixedNode> {
+
+    private static final DebugCounter computeNodeProbabilityCounter = Debug.counter("ComputeNodeProbability");
+
+    private final Map<FixedNode, Double> cache = Node.newIdentityMap();
+
+    /**
+     * <p>
+     * Given a {@link FixedNode} this method finds the most immediate {@link AbstractBeginNode}
+     * preceding it that either:
+     * <ul>
+     * <li>has no predecessor (ie, the begin-node is a merge, in particular a loop-begin, or the
+     * start-node)</li>
+     * <li>has a control-split predecessor</li>
+     * </ul>
+     * </p>
+     *
+     * <p>
+     * The thus found {@link AbstractBeginNode} is equi-probable with the {@link FixedNode} it was
+     * obtained from. When computed for the first time (afterwards a cache lookup returns it) that
+     * probability is computed as follows, again depending on the begin-node's predecessor:
+     * <ul>
+     * <li>No predecessor. In this case the begin-node is either:</li>
+     * <ul>
+     * <li>a merge-node, whose probability adds up those of its forward-ends</li>
+     * <li>a loop-begin, with probability as above multiplied by the loop-frequency</li>
+     * </ul>
+     * <li>Control-split predecessor: probability of the branch times that of the control-split</li>
+     * </ul>
+     * </p>
+     *
+     * <p>
+     * As an exception to all the above, a probability of 1 is assumed for a {@link FixedNode} that
+     * appears to be dead-code (ie, lacks a predecessor).
+     * </p>
+     *
+     */
+    @Override
+    public double applyAsDouble(FixedNode node) {
+        assert node != null;
+        computeNodeProbabilityCounter.increment();
+
+        FixedNode current = findBegin(node);
+        if (current == null) {
+            // this should only appear for dead code
+            return 1D;
+        }
+
+        assert current instanceof AbstractBeginNode;
+        Double cachedValue = cache.get(current);
+        if (cachedValue != null) {
+            return cachedValue;
+        }
+
+        double probability = 0.0;
+        if (current.predecessor() == null) {
+            if (current instanceof AbstractMergeNode) {
+                probability = handleMerge(current, probability);
+            } else {
+                assert current instanceof StartNode;
+                probability = 1D;
+            }
+        } else {
+            ControlSplitNode split = (ControlSplitNode) current.predecessor();
+            probability = split.probability((AbstractBeginNode) current) * applyAsDouble(split);
+        }
+        assert !Double.isNaN(probability) && !Double.isInfinite(probability) : current + " " + probability;
+        cache.put(current, probability);
+        return probability;
+    }
+
+    private double handleMerge(FixedNode current, double probability) {
+        double result = probability;
+        AbstractMergeNode currentMerge = (AbstractMergeNode) current;
+        NodeInputList<EndNode> currentForwardEnds = currentMerge.forwardEnds();
+        /*
+         * Use simple iteration instead of streams, since the stream infrastructure adds many frames
+         * which causes the recursion to overflow the stack earlier than it would otherwise.
+         */
+        for (AbstractEndNode endNode : currentForwardEnds) {
+            result += applyAsDouble(endNode);
+        }
+        if (current instanceof LoopBeginNode) {
+            result *= ((LoopBeginNode) current).loopFrequency();
+        }
+        return result;
+    }
+
+    private static FixedNode findBegin(FixedNode node) {
+        FixedNode current = node;
+        while (true) {
+            assert current != null;
+            Node predecessor = current.predecessor();
+            if (current instanceof AbstractBeginNode) {
+                if (predecessor == null) {
+                    break;
+                } else if (predecessor.successors().count() != 1) {
+                    assert predecessor instanceof ControlSplitNode : "a FixedNode with multiple successors needs to be a ControlSplitNode: " + current + " / " + predecessor;
+                    break;
+                }
+            } else if (predecessor == null) {
+                current = null;
+                break;
+            }
+            current = (FixedNode) predecessor;
+        }
+        return current;
+    }
+}