--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/spi/Canonicalizable.java	2017-02-15 16:58:45.426007852 -0800
@@ -0,0 +1,156 @@
+/*
+ * 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.graph.spi;
+
+import org.graalvm.compiler.graph.Graph;
+import org.graalvm.compiler.graph.Node;
+
+import jdk.vm.ci.meta.MetaAccessProvider;
+
+/**
+ * Nodes can implement {@link Canonicalizable} or one of the two sub-interfaces {@link Unary} and
+ * {@link Binary} to provide local optimizations like constant folding and strength reduction.
+ * Implementations should return a replacement that is always semantically correct for the given
+ * inputs, or "this" if they do not see an opportunity for improvement.<br/>
+ * <br/>
+ * <b>Implementations of {@link Canonicalizable#canonical(CanonicalizerTool)} or the equivalent
+ * methods of the two sub-interfaces must not have any side effects.</b><br/>
+ * They are not allowed to change inputs, successors or properties of any node (including the
+ * current one) and they also cannot add new nodes to the graph.<br/>
+ * <br/>
+ * In addition to pre-existing nodes they can return newly created nodes, which will be added to the
+ * graph automatically if (and only if) the effects of the canonicalization are committed.
+ * Non-cyclic graphs (DAGs) of newly created nodes (i.e., one newly created node with an input to
+ * another newly created node) will be handled correctly.
+ */
+public interface Canonicalizable {
+
+    /**
+     * Implementations of this method can provide local optimizations like constant folding and
+     * strength reduction. Implementations should look at the properties and inputs of the current
+     * node and determine if there is a more optimal and always semantically correct replacement.
+     * <br/>
+     * The return value determines the effect that the canonicalization will have:
+     * <ul>
+     * <li>Returning an pre-existing node will replace the current node with the given one.</li>
+     * <li>Returning a newly created node (that was not yet added to the graph) will replace the
+     * current node with the given one, after adding it to the graph. If both the replacement and
+     * the replacee are anchored in control flow (fixed nodes), the replacement will be added to the
+     * control flow. It is invalid to replace a non-fixed node with a newly created fixed node
+     * (because its placement in the control flow cannot be determined without scheduling).</li>
+     * <li>Returning {@code null} will delete the current node and replace it with {@code null} at
+     * all usages. Note that it is not necessary to delete floating nodes that have no more usages
+     * this way - they will be deleted automatically.</li>
+     * </ul>
+     *
+     * @param tool provides access to runtime interfaces like {@link MetaAccessProvider}
+     */
+    Node canonical(CanonicalizerTool tool);
+
+    /**
+     * This sub-interface of {@link Canonicalizable} is intended for nodes that have exactly one
+     * input. It has an additional {@link #canonical(CanonicalizerTool, Node)} method that looks at
+     * the given input instead of the current input of the node - which can be used to ask "what if
+     * this input is changed to this node" - questions.
+     *
+     * @param <T> the common supertype of all inputs of this node
+     */
+    public interface Unary<T extends Node> extends Canonicalizable {
+
+        /**
+         * Similar to {@link Canonicalizable#canonical(CanonicalizerTool)}, except that
+         * implementations should act as if the current input of the node was the given one, i.e.,
+         * they should never look at the inputs via the this pointer.
+         */
+        Node canonical(CanonicalizerTool tool, T forValue);
+
+        /**
+         * Gets the current value of the input, so that calling
+         * {@link #canonical(CanonicalizerTool, Node)} with the value returned from this method
+         * should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+         */
+        T getValue();
+
+        @SuppressWarnings("unchecked")
+        @Override
+        default T canonical(CanonicalizerTool tool) {
+            return (T) canonical(tool, getValue());
+        }
+    }
+
+    /**
+     * This sub-interface of {@link Canonicalizable} is intended for nodes that have exactly two
+     * inputs. It has an additional {@link #canonical(CanonicalizerTool, Node, Node)} method that
+     * looks at the given inputs instead of the current inputs of the node - which can be used to
+     * ask "what if this input is changed to this node" - questions.
+     *
+     * @param <T> the common supertype of all inputs of this node
+     */
+    public interface Binary<T extends Node> extends Canonicalizable {
+
+        /**
+         * Similar to {@link Canonicalizable#canonical(CanonicalizerTool)}, except that
+         * implementations should act as if the current input of the node was the given one, i.e.,
+         * they should never look at the inputs via the this pointer.
+         */
+        Node canonical(CanonicalizerTool tool, T forX, T forY);
+
+        /**
+         * Gets the current value of the input, so that calling
+         * {@link #canonical(CanonicalizerTool, Node, Node)} with the value returned from this
+         * method should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+         */
+        T getX();
+
+        /**
+         * Gets the current value of the input, so that calling
+         * {@link #canonical(CanonicalizerTool, Node, Node)} with the value returned from this
+         * method should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+         */
+        T getY();
+
+        @SuppressWarnings("unchecked")
+        @Override
+        default T canonical(CanonicalizerTool tool) {
+            return (T) canonical(tool, getX(), getY());
+        }
+    }
+
+    /**
+     * This sub-interface of {@link Canonicalizable.Binary} is for nodes with two inputs where the
+     * operation is commutative. It is used to improve GVN by trying to merge nodes with the same
+     * inputs in different order.
+     */
+    public interface BinaryCommutative<T extends Node> extends Binary<T> {
+
+        /**
+         * Ensure a canonical ordering of inputs for commutative nodes to improve GVN results. Order
+         * the inputs by increasing {@link Node#id} and call {@link Graph#findDuplicate(Node)} on
+         * the node if it's currently in a graph. It's assumed that if there was a constant on the
+         * left it's been moved to the right by other code and that ordering is left alone.
+         *
+         * @return the original node or another node with the same input ordering
+         */
+        Node maybeCommuteInputs();
+    }
+}