001/*
002 * Copyright (c) 2012, 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.loop;
024
025import static com.oracle.graal.loop.MathUtil.*;
026import jdk.internal.jvmci.common.*;
027
028import com.oracle.graal.compiler.common.type.*;
029import com.oracle.graal.nodes.*;
030import com.oracle.graal.nodes.calc.*;
031
032public class DerivedOffsetInductionVariable extends DerivedInductionVariable {
033
034    private final ValueNode offset;
035    private final BinaryArithmeticNode<?> value;
036
037    public DerivedOffsetInductionVariable(LoopEx loop, InductionVariable base, ValueNode offset, BinaryArithmeticNode<?> value) {
038        super(loop, base);
039        this.offset = offset;
040        this.value = value;
041    }
042
043    public ValueNode getOffset() {
044        return offset;
045    }
046
047    @Override
048    public Direction direction() {
049        return base.direction();
050    }
051
052    @Override
053    public ValueNode valueNode() {
054        return value;
055    }
056
057    @Override
058    public boolean isConstantInit() {
059        return offset.isConstant() && base.isConstantInit();
060    }
061
062    @Override
063    public boolean isConstantStride() {
064        return base.isConstantStride();
065    }
066
067    @Override
068    public long constantInit() {
069        return op(base.constantInit(), offset.asJavaConstant().asLong());
070    }
071
072    @Override
073    public long constantStride() {
074        if (value instanceof SubNode && base.valueNode() == value.getY()) {
075            return -base.constantStride();
076        }
077        return base.constantStride();
078    }
079
080    @Override
081    public ValueNode initNode() {
082        return op(base.initNode(), offset);
083    }
084
085    @Override
086    public ValueNode strideNode() {
087        if (value instanceof SubNode && base.valueNode() == value.getY()) {
088            return graph().unique(new NegateNode(base.strideNode()));
089        }
090        return base.strideNode();
091    }
092
093    @Override
094    public ValueNode extremumNode(boolean assumePositiveTripCount, Stamp stamp) {
095        return op(base.extremumNode(assumePositiveTripCount, stamp), IntegerConvertNode.convert(offset, stamp, graph()));
096    }
097
098    @Override
099    public ValueNode exitValueNode() {
100        return op(base.exitValueNode(), offset);
101    }
102
103    @Override
104    public boolean isConstantExtremum() {
105        return offset.isConstant() && base.isConstantExtremum();
106    }
107
108    @Override
109    public long constantExtremum() {
110        return op(base.constantExtremum(), offset.asJavaConstant().asLong());
111    }
112
113    private long op(long b, long o) {
114        if (value instanceof AddNode) {
115            return b + o;
116        }
117        if (value instanceof SubNode) {
118            if (base.valueNode() == value.getX()) {
119                return b - o;
120            } else {
121                assert base.valueNode() == value.getY();
122                return o - b;
123            }
124        }
125        throw JVMCIError.shouldNotReachHere();
126    }
127
128    private ValueNode op(ValueNode b, ValueNode o) {
129        if (value instanceof AddNode) {
130            return add(graph(), b, o);
131        }
132        if (value instanceof SubNode) {
133            if (base.valueNode() == value.getX()) {
134                return sub(graph(), b, o);
135            } else {
136                assert base.valueNode() == value.getY();
137                return sub(graph(), o, b);
138            }
139        }
140        throw JVMCIError.shouldNotReachHere();
141    }
142
143    @Override
144    public void deleteUnusedNodes() {
145    }
146
147    @Override
148    public String toString() {
149        return String.format("DerivedOffsetInductionVariable base (%s) %s %s", base, value.getNodeClass().shortName(), offset);
150    }
151}