001/*
002 * Copyright (c) 2011, 2015, 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.nodes.calc;
024
025import jdk.internal.jvmci.code.*;
026import jdk.internal.jvmci.meta.*;
027
028import com.oracle.graal.compiler.common.calc.*;
029import com.oracle.graal.compiler.common.type.*;
030import com.oracle.graal.graph.*;
031import com.oracle.graal.graph.spi.*;
032import com.oracle.graal.nodeinfo.*;
033import com.oracle.graal.nodes.*;
034import com.oracle.graal.nodes.util.*;
035
036@NodeInfo(shortName = "|<|")
037public final class IntegerBelowNode extends CompareNode {
038    public static final NodeClass<IntegerBelowNode> TYPE = NodeClass.create(IntegerBelowNode.class);
039
040    public IntegerBelowNode(ValueNode x, ValueNode y) {
041        super(TYPE, Condition.BT, false, x, y);
042        assert x.stamp() instanceof IntegerStamp;
043        assert y.stamp() instanceof IntegerStamp;
044    }
045
046    public static LogicNode create(ValueNode x, ValueNode y, ConstantReflectionProvider constantReflection) {
047        LogicNode result = CompareNode.tryConstantFold(Condition.BT, x, y, constantReflection, false);
048        if (result != null) {
049            return result;
050        } else {
051            result = findSynonym(x, y);
052            if (result != null) {
053                return result;
054            }
055            return new IntegerBelowNode(x, y);
056        }
057    }
058
059    @Override
060    public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
061        ValueNode result = super.canonical(tool, forX, forY);
062        if (result != this) {
063            return result;
064        }
065        LogicNode synonym = findSynonym(forX, forY);
066        if (synonym != null) {
067            return synonym;
068        }
069        if (forX.isConstant() && forX.asJavaConstant().asLong() == 0) {
070            // 0 |<| y is the same as 0 != y
071            return LogicNegationNode.create(CompareNode.createCompareNode(Condition.EQ, forX, forY, tool.getConstantReflection()));
072        }
073        return this;
074    }
075
076    private static LogicNode findSynonym(ValueNode forX, ValueNode forY) {
077        if (GraphUtil.unproxify(forX) == GraphUtil.unproxify(forY)) {
078            return LogicConstantNode.contradiction();
079        } else if (forX.stamp() instanceof IntegerStamp && forY.stamp() instanceof IntegerStamp) {
080            IntegerStamp xStamp = (IntegerStamp) forX.stamp();
081            IntegerStamp yStamp = (IntegerStamp) forY.stamp();
082            if (yStamp.isPositive()) {
083                if (xStamp.isPositive() && xStamp.upperBound() < yStamp.lowerBound()) {
084                    return LogicConstantNode.tautology();
085                } else if (xStamp.isStrictlyNegative() || xStamp.lowerBound() >= yStamp.upperBound()) {
086                    return LogicConstantNode.contradiction();
087                }
088            }
089        }
090        return null;
091    }
092
093    @Override
094    protected CompareNode duplicateModified(ValueNode newX, ValueNode newY) {
095        return new IntegerBelowNode(newX, newY);
096    }
097
098    @Override
099    public Stamp getSucceedingStampForX(boolean negated) {
100        Stamp xStampGeneric = getX().stamp();
101        Stamp yStampGeneric = getY().stamp();
102        if (xStampGeneric instanceof IntegerStamp) {
103            IntegerStamp xStamp = (IntegerStamp) xStampGeneric;
104            int bits = xStamp.getBits();
105            if (yStampGeneric instanceof IntegerStamp) {
106                IntegerStamp yStamp = (IntegerStamp) yStampGeneric;
107                assert yStamp.getBits() == bits;
108                if (negated) {
109                    // x >= y
110                    if (xStamp.isPositive() && yStamp.isPositive()) {
111                        long xLowerBound = xStamp.lowerBound();
112                        long yLowerBound = yStamp.lowerBound();
113                        if (yLowerBound > xLowerBound) {
114                            return new IntegerStamp(bits, yLowerBound, xStamp.upperBound(), xStamp.downMask(), xStamp.upMask());
115                        }
116                    }
117                } else {
118                    // x < y
119                    if (yStamp.isStrictlyPositive()) {
120                        // x >= 0 && x < y
121                        long xUpperBound = xStamp.upperBound();
122                        long yUpperBound = yStamp.upperBound();
123                        if (yUpperBound <= xUpperBound || !xStamp.isPositive()) {
124                            return new IntegerStamp(bits, Math.max(0, xStamp.lowerBound()), Math.min(xUpperBound, yUpperBound - 1), xStamp.downMask(), xStamp.upMask());
125                        }
126                    }
127                }
128            }
129        }
130        return null;
131    }
132
133    @Override
134    public Stamp getSucceedingStampForY(boolean negated) {
135        Stamp xStampGeneric = getX().stamp();
136        Stamp yStampGeneric = getY().stamp();
137        if (xStampGeneric instanceof IntegerStamp) {
138            IntegerStamp xStamp = (IntegerStamp) xStampGeneric;
139            int bits = xStamp.getBits();
140            if (yStampGeneric instanceof IntegerStamp) {
141                IntegerStamp yStamp = (IntegerStamp) yStampGeneric;
142                assert yStamp.getBits() == bits;
143                if (negated) {
144                    // y <= x
145                    if (xStamp.isPositive()) {
146                        long xUpperBound = xStamp.upperBound();
147                        long yUpperBound = yStamp.upperBound();
148                        if (xUpperBound < yUpperBound || !yStamp.isPositive()) {
149                            return new IntegerStamp(bits, Math.max(0, yStamp.lowerBound()), Math.min(xUpperBound, yUpperBound), yStamp.downMask(), yStamp.upMask());
150                        }
151                    }
152                } else {
153                    // y > x
154                    if (xStamp.isPositive() && yStamp.isPositive()) {
155                        long xLowerBound = xStamp.lowerBound();
156                        long yLowerBound = yStamp.lowerBound();
157                        if (xLowerBound == CodeUtil.maxValue(bits)) {
158                            return null;
159                        } else if (xLowerBound >= yLowerBound) {
160                            assert xLowerBound != CodeUtil.maxValue(bits);
161                            return new IntegerStamp(bits, xLowerBound + 1, yStamp.upperBound(), yStamp.downMask(), yStamp.upMask());
162                        }
163                    }
164                }
165            }
166        }
167        return null;
168    }
169
170    @Override
171    public TriState tryFold(Stamp xStampGeneric, Stamp yStampGeneric) {
172        if (xStampGeneric instanceof IntegerStamp) {
173            IntegerStamp xStamp = (IntegerStamp) xStampGeneric;
174            if (yStampGeneric instanceof IntegerStamp) {
175                IntegerStamp yStamp = (IntegerStamp) yStampGeneric;
176                if (yStamp.isPositive()) {
177                    if (xStamp.isPositive() && xStamp.upperBound() < yStamp.lowerBound()) {
178                        return TriState.TRUE;
179                    } else if (xStamp.isStrictlyNegative() || xStamp.lowerBound() >= yStamp.upperBound()) {
180                        return TriState.FALSE;
181                    }
182                }
183            }
184        }
185        return TriState.UNKNOWN;
186    }
187}