1 /*
   2  * Copyright (c) 2011, 2015, 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.ArithmeticOpTable;
  26 import org.graalvm.compiler.core.common.type.ArithmeticOpTable.ShiftOp.Shl;
  27 import org.graalvm.compiler.graph.NodeClass;
  28 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  29 import org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool;
  30 import org.graalvm.compiler.nodeinfo.NodeInfo;
  31 import org.graalvm.compiler.nodes.ConstantNode;
  32 import org.graalvm.compiler.nodes.ValueNode;
  33 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  34 
  35 import jdk.vm.ci.meta.JavaKind;
  36 
  37 @NodeInfo(shortName = "<<")
  38 public final class LeftShiftNode extends ShiftNode<Shl> {
  39 
  40     public static final NodeClass<LeftShiftNode> TYPE = NodeClass.create(LeftShiftNode.class);
  41 
  42     public LeftShiftNode(ValueNode x, ValueNode y) {
  43         super(TYPE, ArithmeticOpTable::getShl, x, y);
  44     }
  45 
  46     @Override
  47     public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
  48         ValueNode ret = super.canonical(tool, forX, forY);
  49         if (ret != this) {
  50             return ret;
  51         }
  52 
  53         if (forY.isConstant()) {
  54             int amount = forY.asJavaConstant().asInt();
  55             int originalAmout = amount;
  56             int mask = getShiftAmountMask();
  57             amount &= mask;
  58             if (amount == 0) {
  59                 return forX;
  60             }
  61             if (forX instanceof ShiftNode) {
  62                 ShiftNode<?> other = (ShiftNode<?>) forX;
  63                 if (other.getY().isConstant()) {
  64                     int otherAmount = other.getY().asJavaConstant().asInt() & mask;
  65                     if (other instanceof LeftShiftNode) {
  66                         int total = amount + otherAmount;
  67                         if (total != (total & mask)) {
  68                             return ConstantNode.forIntegerKind(getStackKind(), 0);
  69                         }
  70                         return new LeftShiftNode(other.getX(), ConstantNode.forInt(total));
  71                     } else if ((other instanceof RightShiftNode || other instanceof UnsignedRightShiftNode) && otherAmount == amount) {
  72                         if (getStackKind() == JavaKind.Long) {
  73                             return new AndNode(other.getX(), ConstantNode.forLong(-1L << amount));
  74                         } else {
  75                             assert getStackKind() == JavaKind.Int;
  76                             return new AndNode(other.getX(), ConstantNode.forInt(-1 << amount));
  77                         }
  78                     }
  79                 }
  80             }
  81             if (originalAmout != amount) {
  82                 return new LeftShiftNode(forX, ConstantNode.forInt(amount));
  83             }
  84         }
  85         return this;
  86     }
  87 
  88     @Override
  89     public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
  90         nodeValueMap.setResult(this, gen.emitShl(nodeValueMap.operand(getX()), nodeValueMap.operand(getY())));
  91     }
  92 }