001/*
002 * Copyright (c) 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.replacements.nodes;
024
025import java.util.*;
026
027import com.oracle.graal.compiler.common.type.*;
028import com.oracle.graal.graph.*;
029import com.oracle.graal.nodeinfo.*;
030import com.oracle.graal.nodes.*;
031import com.oracle.graal.replacements.Snippet.VarargsParameter;
032
033/**
034 * Placeholder node to denote to snippet preparation that the following loop must be completely
035 * unrolled.
036 *
037 * @see VarargsParameter
038 */
039@NodeInfo
040public final class ExplodeLoopNode extends FixedWithNextNode {
041    public static final NodeClass<ExplodeLoopNode> TYPE = NodeClass.create(ExplodeLoopNode.class);
042
043    public ExplodeLoopNode() {
044        super(TYPE, StampFactory.forVoid());
045    }
046
047    public LoopBeginNode findLoopBegin() {
048        Node currentNext = next();
049        ArrayList<Node> succs = new ArrayList<>();
050        while (!(currentNext instanceof LoopBeginNode)) {
051            assert currentNext != null : "cannot find loop after " + this;
052            for (Node n : currentNext.cfgSuccessors()) {
053                succs.add(n);
054            }
055            if (succs.size() == 1) {
056                currentNext = succs.get(0);
057            } else {
058                return null;
059            }
060        }
061        return (LoopBeginNode) currentNext;
062    }
063
064    /**
065     * A call to this method must be placed immediately prior to the loop that is to be exploded.
066     */
067    @NodeIntrinsic
068    public static native void explodeLoop();
069}