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
  21  * questions.
  22  */
  23 package org.graalvm.compiler.nodes.calc;
  24 
  25 import org.graalvm.compiler.core.common.type.IntegerStamp;
  26 import org.graalvm.compiler.core.common.type.PrimitiveStamp;
  27 import org.graalvm.compiler.graph.NodeClass;
  28 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  29 import org.graalvm.compiler.nodeinfo.NodeInfo;
  30 import org.graalvm.compiler.nodes.ConstantNode;
  31 import org.graalvm.compiler.nodes.ValueNode;
  32 import org.graalvm.compiler.nodes.spi.LIRLowerable;
  33 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  34 
  35 import jdk.vm.ci.code.CodeUtil;
  36 
  37 @NodeInfo(shortName = "/")
  38 public 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 NegateNode.create(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 NegateNode.create(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                     SignedDivNode sd = new SignedDivNode(integerSubNode.getX(), forY);
 100                     sd.stateBefore = this.stateBefore;
 101                     return sd;
 102                 }
 103             }
 104         }
 105 
 106         if (next() instanceof SignedDivNode) {
 107             NodeClass<?> nodeClass = getNodeClass();
 108             if (next().getClass() == this.getClass() && nodeClass.equalInputs(this, next()) && valueEquals(next())) {
 109                 return next();
 110             }
 111         }
 112 
 113         return this;




























 114     }
 115 
 116     @Override
 117     public void generate(NodeLIRBuilderTool gen) {
 118         gen.setResult(this, gen.getLIRGeneratorTool().getArithmetic().emitDiv(gen.operand(getX()), gen.operand(getY()), gen.state(this)));
 119     }
 120 }
--- EOF ---