SignedDivNode.java revision 12657:6ef01bd40ce2 
1/*
2 * Copyright (c) 2011, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
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23package org.graalvm.compiler.nodes.calc;
24
25import org.graalvm.compiler.core.common.type.IntegerStamp;
26import org.graalvm.compiler.core.common.type.PrimitiveStamp;
27import org.graalvm.compiler.graph.NodeClass;
28import org.graalvm.compiler.graph.spi.CanonicalizerTool;
29import org.graalvm.compiler.nodeinfo.NodeInfo;
30import org.graalvm.compiler.nodes.ConstantNode;
31import org.graalvm.compiler.nodes.ValueNode;
32import org.graalvm.compiler.nodes.spi.LIRLowerable;
33import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
34
35import jdk.vm.ci.code.CodeUtil;
36
37@NodeInfo(shortName = "/")
38public class SignedDivNode extends IntegerDivRemNode implements LIRLowerable {
39
40    public static final NodeClass<SignedDivNode> TYPE = NodeClass.create(SignedDivNode.class);
41
42    public SignedDivNode(ValueNode x, ValueNode y) {
43        this(TYPE, x, y);
44    }
45
46    protected SignedDivNode(NodeClass<? extends SignedDivNode> c, ValueNode x, ValueNode y) {
47        super(c, IntegerStamp.OPS.getDiv().foldStamp(x.stamp(), y.stamp()), Op.DIV, Type.SIGNED, x, y);
48    }
49
50    @Override
51    public boolean inferStamp() {
52        return updateStamp(IntegerStamp.OPS.getDiv().foldStamp(getX().stamp(), getY().stamp()));
53    }
54
55    @Override
56    public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
57        if (forX.isConstant() && forY.isConstant()) {
58            @SuppressWarnings("hiding")
59            long y = forY.asJavaConstant().asLong();
60            if (y == 0) {
61                return this; // this will trap, can not canonicalize
62            }
63            return ConstantNode.forIntegerStamp(stamp(), forX.asJavaConstant().asLong() / y);
64        } else if (forY.isConstant()) {
65            long c = forY.asJavaConstant().asLong();
66            if (c == 1) {
67                return forX;
68            }
69            if (c == -1) {
70                return new NegateNode(forX);
71            }
72            long abs = Math.abs(c);
73            if (CodeUtil.isPowerOf2(abs) && forX.stamp() instanceof IntegerStamp) {
74                ValueNode dividend = forX;
75                IntegerStamp stampX = (IntegerStamp) forX.stamp();
76                int log2 = CodeUtil.log2(abs);
77                // no rounding if dividend is positive or if its low bits are always 0
78                if (stampX.canBeNegative() || (stampX.upMask() & (abs - 1)) != 0) {
79                    int bits = PrimitiveStamp.getBits(stamp());
80                    RightShiftNode sign = new RightShiftNode(forX, ConstantNode.forInt(bits - 1));
81                    UnsignedRightShiftNode round = new UnsignedRightShiftNode(sign, ConstantNode.forInt(bits - log2));
82                    dividend = BinaryArithmeticNode.add(dividend, round);
83                }
84                RightShiftNode shift = new RightShiftNode(dividend, ConstantNode.forInt(log2));
85                if (c < 0) {
86                    return new NegateNode(shift);
87                }
88                return shift;
89            }
90        }
91
92        // Convert the expression ((a - a % b) / b) into (a / b).
93        if (forX instanceof SubNode) {
94            SubNode integerSubNode = (SubNode) forX;
95            if (integerSubNode.getY() instanceof SignedRemNode) {
96                SignedRemNode integerRemNode = (SignedRemNode) integerSubNode.getY();
97                if (integerSubNode.stamp().isCompatible(this.stamp()) && integerRemNode.stamp().isCompatible(this.stamp()) && integerSubNode.getX() == integerRemNode.getX() &&
98                                forY == integerRemNode.getY()) {
99                    return new SignedDivNode(integerSubNode.getX(), forY);
100                }
101            }
102        }
103
104        if (next() instanceof SignedDivNode) {
105            NodeClass<?> nodeClass = getNodeClass();
106            if (next().getClass() == this.getClass() && nodeClass.equalInputs(this, next()) && valueEquals(next())) {
107                return next();
108            }
109        }
110
111        return this;
112    }
113
114    @Override
115    public void generate(NodeLIRBuilderTool gen) {
116        gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitDiv(gen.operand(getX()), gen.operand(getY()), gen.state(this)));
117    }
118}
119