--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.java/src/org/graalvm/compiler/java/ComputeLoopFrequenciesClosure.java	2016-12-07 13:50:57.177300422 -0800
@@ -0,0 +1,118 @@
+/*
+ * 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.java;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.graalvm.compiler.nodes.AbstractBeginNode;
+import org.graalvm.compiler.nodes.AbstractMergeNode;
+import org.graalvm.compiler.nodes.ControlSplitNode;
+import org.graalvm.compiler.nodes.FixedNode;
+import org.graalvm.compiler.nodes.LoopBeginNode;
+import org.graalvm.compiler.nodes.LoopExitNode;
+import org.graalvm.compiler.nodes.StructuredGraph;
+import org.graalvm.compiler.nodes.cfg.ControlFlowGraph;
+import org.graalvm.compiler.phases.Phase;
+import org.graalvm.compiler.phases.graph.ReentrantNodeIterator;
+
+public final class ComputeLoopFrequenciesClosure extends ReentrantNodeIterator.NodeIteratorClosure<Double> {
+
+    private static final ComputeLoopFrequenciesClosure INSTANCE = new ComputeLoopFrequenciesClosure();
+
+    private ComputeLoopFrequenciesClosure() {
+        // nothing to do
+    }
+
+    @Override
+    protected Double processNode(FixedNode node, Double currentState) {
+        // normal nodes never change the probability of a path
+        return currentState;
+    }
+
+    @Override
+    protected Double merge(AbstractMergeNode merge, List<Double> states) {
+        // a merge has the sum of all predecessor probabilities
+        return states.stream().collect(Collectors.summingDouble(d -> d));
+    }
+
+    @Override
+    protected Double afterSplit(AbstractBeginNode node, Double oldState) {
+        // a control split splits up the probability
+        ControlSplitNode split = (ControlSplitNode) node.predecessor();
+        return oldState * split.probability(node);
+    }
+
+    @Override
+    protected Map<LoopExitNode, Double> processLoop(LoopBeginNode loop, Double initialState) {
+        Map<LoopExitNode, Double> exitStates = ReentrantNodeIterator.processLoop(this, loop, 1D).exitStates;
+
+        double exitProbability = exitStates.values().stream().mapToDouble(d -> d).sum();
+        exitProbability = Math.min(1D, exitProbability);
+        if (exitProbability < ControlFlowGraph.MIN_PROBABILITY) {
+            exitProbability = ControlFlowGraph.MIN_PROBABILITY;
+        }
+        assert exitProbability <= 1D && exitProbability >= 0D;
+        double loopFrequency = 1D / exitProbability;
+        loop.setLoopFrequency(loopFrequency);
+
+        double adjustmentFactor = initialState * loopFrequency;
+        exitStates.replaceAll((exitNode, probability) -> multiplySaturate(probability, adjustmentFactor));
+
+        return exitStates;
+    }
+
+    /**
+     * Multiplies a and b and saturates the result to {@link ControlFlowGraph#MAX_PROBABILITY}.
+     */
+    public static double multiplySaturate(double a, double b) {
+        double r = a * b;
+        if (r > ControlFlowGraph.MAX_PROBABILITY) {
+            return ControlFlowGraph.MAX_PROBABILITY;
+        }
+        return r;
+    }
+
+    /**
+     * Computes the frequencies of all loops in the given graph. This is done by performing a
+     * reverse postorder iteration and computing the probability of all fixed nodes. The combined
+     * probability of all exits of a loop can be used to compute the loop's expected frequency.
+     */
+    public static void compute(StructuredGraph graph) {
+        if (graph.hasLoops()) {
+            ReentrantNodeIterator.apply(INSTANCE, graph.start(), 1D);
+        }
+    }
+
+    public static class ComputeLoopFrequencyPhase extends Phase {
+
+        @Override
+        protected void run(StructuredGraph graph) {
+            compute(graph);
+        }
+    }
+
+    public static final ComputeLoopFrequencyPhase PHASE_INSTANCE = new ComputeLoopFrequencyPhase();
+
+}