001/*
002 * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.loop.phases;
024
025import java.util.*;
026
027import com.oracle.graal.debug.*;
028
029import com.oracle.graal.graph.*;
030import com.oracle.graal.loop.*;
031import com.oracle.graal.nodes.*;
032import com.oracle.graal.phases.*;
033
034public class LoopUnswitchingPhase extends Phase {
035
036    private static final DebugMetric UNSWITCHED = Debug.metric("Unswitched");
037    private static final DebugMetric UNSWITCH_CANDIDATES = Debug.metric("UnswitchCandidates");
038    private static final DebugMetric UNSWITCH_EARLY_REJECTS = Debug.metric("UnswitchEarlyRejects");
039
040    @Override
041    protected void run(StructuredGraph graph) {
042        if (graph.hasLoops()) {
043            boolean unswitched;
044            do {
045                unswitched = false;
046                final LoopsData dataUnswitch = new LoopsData(graph);
047                for (LoopEx loop : dataUnswitch.outerFirst()) {
048                    if (LoopPolicies.shouldTryUnswitch(loop)) {
049                        List<ControlSplitNode> controlSplits = LoopTransformations.findUnswitchable(loop);
050                        if (controlSplits != null) {
051                            UNSWITCH_CANDIDATES.increment();
052                            if (LoopPolicies.shouldUnswitch(loop, controlSplits)) {
053                                if (Debug.isLogEnabled()) {
054                                    logUnswitch(loop, controlSplits);
055                                }
056                                LoopTransformations.unswitch(loop, controlSplits);
057                                UNSWITCHED.increment();
058                                unswitched = true;
059                                break;
060                            }
061                        }
062                    } else {
063                        UNSWITCH_EARLY_REJECTS.increment();
064                    }
065                }
066            } while (unswitched);
067        }
068    }
069
070    private static void logUnswitch(LoopEx loop, List<ControlSplitNode> controlSplits) {
071        StringBuilder sb = new StringBuilder("Unswitching ");
072        sb.append(loop).append(" at ");
073        for (ControlSplitNode controlSplit : controlSplits) {
074            sb.append(controlSplit).append(" [");
075            NodePosIterator it = controlSplit.successors().iterator();
076            while (it.hasNext()) {
077                sb.append(controlSplit.probability((AbstractBeginNode) it.next()));
078                if (it.hasNext()) {
079                    sb.append(", ");
080                }
081            }
082            sb.append("]");
083        }
084        Debug.log("%s", sb);
085    }
086}