/*
 * Copyright (c) 2011, 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 com.oracle.graal.compiler.phases;

import com.oracle.graal.debug.*;
import com.oracle.graal.graph.*;
import com.oracle.graal.nodes.*;

public class GlobalValueNumberingPhase extends Phase {

    public static final DebugMetric metricGlobalValueNumberingHits = Debug.metric("GlobalValueNumberingHits");

    @Override
    protected void run(StructuredGraph graph) {
        NodeBitMap visited = graph.createNodeBitMap();
        for (Node n : graph.getNodes()) {
            apply(n, visited, graph);
        }
    }

    private void apply(Node n, NodeBitMap visited, StructuredGraph compilerGraph) {
        if (!visited.isMarked(n)) {
            visited.mark(n);
            for (Node input : n.inputs()) {
                apply(input, visited, compilerGraph);
            }
            if (n.getNodeClass().valueNumberable()) {
                Node newNode = compilerGraph.findDuplicate(n);
                if (newNode != null) {
                    assert !(n instanceof FixedNode || newNode instanceof FixedNode);
                    n.replaceAtUsages(newNode);
                    n.safeDelete();
                    metricGlobalValueNumberingHits.increment();
                    Debug.log("GVN applied and new node is %1s", newNode);
                }
            }
        }
    }
}