/*
 * 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.max.graal.compiler.phases;

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

public class PhiStampPhase extends Phase {
    @Override
    protected void run(StructuredGraph graph) {
        // Infer phis stopping at loop phis.
        for (PhiNode phi : graph.getNodes(PhiNode.class)) {
            inferPhi(phi);
        }

        // Start iterative inference for loop phis.
        if (graph.hasLoops()) {
            for (PhiNode phi : graph.getNodes(PhiNode.class)) {
                if (phi.isLoopPhi()) {
                    iterativeInferPhi(phi);
                }
            }
        }
    }

    private void iterativeInferPhi(PhiNode phi) {
        if (phi.inferStamp()) {
            for (Node n : phi.usages()) {
                if (n instanceof PhiNode) {
                    PhiNode phiUsage = (PhiNode) n;
                    iterativeInferPhi(phiUsage);
                }
            }
        }
    }

    private void inferPhi(PhiNode phi) {
        for (ValueNode v : phi.values()) {
            if (v instanceof PhiNode) {
                PhiNode phiInput = (PhiNode) v;
                if (!phiInput.isLoopPhi()) {
                    inferPhi(phiInput);
                }
            }
        }
        phi.inferStamp();
    }
}