/*
 * Copyright (c) 2012, 2012, 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.loop.phases;

import com.oracle.graal.debug.*;
import com.oracle.graal.graph.NodeClass.NodeClassIterator;
import com.oracle.graal.loop.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.phases.*;

public class LoopTransformLowPhase extends Phase {

    private static final DebugMetric UNSWITCHED = Debug.metric("Unswitched");

    @Override
    protected void run(StructuredGraph graph) {
        if (graph.hasLoops()) {
            if (GraalOptions.ReassociateInvariants) {
                final LoopsData dataReassociate = new LoopsData(graph);
                Debug.scope("ReassociateInvariants", new Runnable() {

                    @Override
                    public void run() {
                        for (LoopEx loop : dataReassociate.loops()) {
                            loop.reassociateInvariants();
                        }
                    }
                });
            }
            if (GraalOptions.LoopUnswitch) {
                boolean unswitched;
                do {
                    unswitched = false;
                    final LoopsData dataUnswitch = new LoopsData(graph);
                    for (LoopEx loop : dataUnswitch.loops()) {
                        if (LoopPolicies.shouldTryUnswitch(loop)) {
                            ControlSplitNode controlSplit = LoopTransformations.findUnswitchable(loop);
                            if (controlSplit != null && LoopPolicies.shouldUnswitch(loop, controlSplit)) {
                                if (Debug.isLogEnabled()) {
                                    logUnswitch(loop, controlSplit);
                                }
                                LoopTransformations.unswitch(loop, controlSplit);
                                UNSWITCHED.increment();
                                Debug.dump(graph, "After unswitch %s", loop);
                                unswitched = true;
                                break;
                            }
                        }
                    }
                } while (unswitched);
            }
        }
    }

    private static void logUnswitch(LoopEx loop, ControlSplitNode controlSplit) {
        StringBuilder sb = new StringBuilder("Unswitching ");
        sb.append(loop).append(" at ").append(controlSplit).append(" [");
        NodeClassIterator it = controlSplit.successors().iterator();
        while (it.hasNext()) {
            sb.append(controlSplit.probability((BeginNode) it.next()));
            if (it.hasNext()) {
                sb.append(", ");
            }
        }
        sb.append("]");
        Debug.log(sb.toString());
    }
}