--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.loop/src/org/graalvm/compiler/loop/CountedLoopInfo.java	2016-12-09 00:54:39.112968963 -0800
@@ -0,0 +1,189 @@
+/*
+ * Copyright (c) 2012, 2015, 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.loop;
+
+import static org.graalvm.compiler.loop.MathUtil.add;
+import static org.graalvm.compiler.loop.MathUtil.divBefore;
+import static org.graalvm.compiler.loop.MathUtil.sub;
+
+import org.graalvm.compiler.core.common.type.IntegerStamp;
+import org.graalvm.compiler.core.common.type.Stamp;
+import org.graalvm.compiler.loop.InductionVariable.Direction;
+import org.graalvm.compiler.nodes.AbstractBeginNode;
+import org.graalvm.compiler.nodes.ConstantNode;
+import org.graalvm.compiler.nodes.GuardNode;
+import org.graalvm.compiler.nodes.StructuredGraph;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.calc.CompareNode;
+import org.graalvm.compiler.nodes.calc.ConditionalNode;
+import org.graalvm.compiler.nodes.calc.IntegerLessThanNode;
+import org.graalvm.compiler.nodes.extended.GuardingNode;
+
+import jdk.vm.ci.code.CodeUtil;
+import jdk.vm.ci.meta.DeoptimizationAction;
+import jdk.vm.ci.meta.DeoptimizationReason;
+import jdk.vm.ci.meta.JavaConstant;
+
+public class CountedLoopInfo {
+
+    private final LoopEx loop;
+    private InductionVariable iv;
+    private ValueNode end;
+    private boolean oneOff;
+    private AbstractBeginNode body;
+
+    CountedLoopInfo(LoopEx loop, InductionVariable iv, ValueNode end, boolean oneOff, AbstractBeginNode body) {
+        this.loop = loop;
+        this.iv = iv;
+        this.end = end;
+        this.oneOff = oneOff;
+        this.body = body;
+    }
+
+    public ValueNode maxTripCountNode() {
+        return maxTripCountNode(false);
+    }
+
+    public ValueNode maxTripCountNode(boolean assumePositive) {
+        StructuredGraph graph = iv.valueNode().graph();
+        Stamp stamp = iv.valueNode().stamp();
+        ValueNode range = sub(graph, end, iv.initNode());
+
+        ValueNode oneDirection;
+        if (iv.direction() == Direction.Up) {
+            oneDirection = ConstantNode.forIntegerStamp(stamp, 1, graph);
+        } else {
+            assert iv.direction() == Direction.Down;
+            oneDirection = ConstantNode.forIntegerStamp(stamp, -1, graph);
+        }
+        if (oneOff) {
+            range = add(graph, range, oneDirection);
+        }
+        // round-away-from-zero divison: (range + stride -/+ 1) / stride
+        ValueNode denominator = add(graph, sub(graph, range, oneDirection), iv.strideNode());
+        ValueNode div = divBefore(graph, loop.entryPoint(), denominator, iv.strideNode());
+
+        if (assumePositive) {
+            return div;
+        }
+        ConstantNode zero = ConstantNode.forIntegerStamp(stamp, 0, graph);
+        return graph.unique(new ConditionalNode(graph.unique(new IntegerLessThanNode(zero, div)), div, zero));
+    }
+
+    public boolean isConstantMaxTripCount() {
+        return end instanceof ConstantNode && iv.isConstantInit() && iv.isConstantStride();
+    }
+
+    public long constantMaxTripCount() {
+        assert iv.direction() != null;
+        long off = oneOff ? iv.direction() == Direction.Up ? 1 : -1 : 0;
+        long max = (((ConstantNode) end).asJavaConstant().asLong() + off - iv.constantInit()) / iv.constantStride();
+        return Math.max(0, max);
+    }
+
+    public boolean isExactTripCount() {
+        return loop.loopBegin().loopExits().count() == 1;
+    }
+
+    public ValueNode exactTripCountNode() {
+        assert isExactTripCount();
+        return maxTripCountNode();
+    }
+
+    public boolean isConstantExactTripCount() {
+        assert isExactTripCount();
+        return isConstantMaxTripCount();
+    }
+
+    public long constantExactTripCount() {
+        assert isExactTripCount();
+        return constantMaxTripCount();
+    }
+
+    @Override
+    public String toString() {
+        return "iv=" + iv + " until " + end + (oneOff ? iv.direction() == Direction.Up ? "+1" : "-1" : "");
+    }
+
+    public ValueNode getLimit() {
+        return end;
+    }
+
+    public ValueNode getStart() {
+        return iv.initNode();
+    }
+
+    public boolean isLimitIncluded() {
+        return oneOff;
+    }
+
+    public AbstractBeginNode getBody() {
+        return body;
+    }
+
+    public Direction getDirection() {
+        return iv.direction();
+    }
+
+    public InductionVariable getCounter() {
+        return iv;
+    }
+
+    public GuardingNode getOverFlowGuard() {
+        return loop.loopBegin().getOverflowGuard();
+    }
+
+    public GuardingNode createOverFlowGuard() {
+        GuardingNode overflowGuard = getOverFlowGuard();
+        if (overflowGuard != null) {
+            return overflowGuard;
+        }
+        IntegerStamp stamp = (IntegerStamp) iv.valueNode().stamp();
+        StructuredGraph graph = iv.valueNode().graph();
+        CompareNode cond; // we use a negated guard with a < condition to achieve a >=
+        ConstantNode one = ConstantNode.forIntegerStamp(stamp, 1, graph);
+        if (iv.direction() == Direction.Up) {
+            ValueNode v1 = sub(graph, ConstantNode.forIntegerStamp(stamp, CodeUtil.maxValue(stamp.getBits()), graph), sub(graph, iv.strideNode(), one));
+            if (oneOff) {
+                v1 = sub(graph, v1, one);
+            }
+            cond = graph.unique(new IntegerLessThanNode(v1, end));
+        } else {
+            assert iv.direction() == Direction.Down;
+            ValueNode v1 = add(graph, ConstantNode.forIntegerStamp(stamp, CodeUtil.minValue(stamp.getBits()), graph), sub(graph, one, iv.strideNode()));
+            if (oneOff) {
+                v1 = add(graph, v1, one);
+            }
+            cond = graph.unique(new IntegerLessThanNode(end, v1));
+        }
+        assert graph.getGuardsStage().allowsFloatingGuards();
+        overflowGuard = graph.unique(new GuardNode(cond, AbstractBeginNode.prevBegin(loop.entryPoint()), DeoptimizationReason.LoopLimitCheck, DeoptimizationAction.InvalidateRecompile, true,
+                        JavaConstant.NULL_POINTER)); // TODO gd: use speculation
+        loop.loopBegin().setOverflowGuard(overflowGuard);
+        return overflowGuard;
+    }
+
+    public IntegerStamp getStamp() {
+        return (IntegerStamp) iv.valueNode().stamp();
+    }
+}