1 /*
   2  * Copyright (c) 2014, 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 static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;
  26 
  27 import org.graalvm.compiler.core.common.type.ArithmeticOpTable;
  28 import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp;
  29 import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.Narrow;
  30 import org.graalvm.compiler.core.common.type.ArithmeticOpTable.IntegerConvertOp.SignExtend;
  31 import org.graalvm.compiler.core.common.type.IntegerStamp;
  32 import org.graalvm.compiler.core.common.type.PrimitiveStamp;
  33 import org.graalvm.compiler.graph.NodeClass;
  34 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  35 import org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool;
  36 import org.graalvm.compiler.nodeinfo.NodeInfo;
  37 import org.graalvm.compiler.nodes.ValueNode;
  38 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  39 
  40 /**
  41  * The {@code SignExtendNode} converts an integer to a wider integer using sign extension.
  42  */
  43 @NodeInfo(cycles = CYCLES_1)
  44 public final class SignExtendNode extends IntegerConvertNode<SignExtend, Narrow> {
  45 
  46     public static final NodeClass<SignExtendNode> TYPE = NodeClass.create(SignExtendNode.class);
  47 
  48     public SignExtendNode(ValueNode input, int resultBits) {
  49         this(input, PrimitiveStamp.getBits(input.stamp()), resultBits);
  50         assert 0 < PrimitiveStamp.getBits(input.stamp()) && PrimitiveStamp.getBits(input.stamp()) <= resultBits;
  51     }
  52 
  53     public SignExtendNode(ValueNode input, int inputBits, int resultBits) {
  54         super(TYPE, ArithmeticOpTable::getSignExtend, ArithmeticOpTable::getNarrow, inputBits, resultBits, input);
  55     }
  56 
  57     public static ValueNode create(ValueNode input, int resultBits) {
  58         return create(input, PrimitiveStamp.getBits(input.stamp()), resultBits);
  59     }
  60 
  61     public static ValueNode create(ValueNode input, int inputBits, int resultBits) {
  62         IntegerConvertOp<SignExtend> signExtend = ArithmeticOpTable.forStamp(input.stamp()).getSignExtend();
  63         ValueNode synonym = findSynonym(signExtend, input, inputBits, resultBits, signExtend.foldStamp(inputBits, resultBits, input.stamp()));
  64         if (synonym != null) {
  65             return synonym;
  66         } else {
  67             return new SignExtendNode(input, inputBits, resultBits);
  68         }
  69     }
  70 
  71     @Override
  72     public boolean isLossless() {
  73         return true;
  74     }
  75 
  76     @Override
  77     public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) {
  78         ValueNode ret = super.canonical(tool, forValue);
  79         if (ret != this) {
  80             return ret;
  81         }
  82 
  83         if (forValue instanceof SignExtendNode) {
  84             // sxxx -(sign-extend)-> ssss sxxx -(sign-extend)-> ssssssss sssssxxx
  85             // ==> sxxx -(sign-extend)-> ssssssss sssssxxx
  86             SignExtendNode other = (SignExtendNode) forValue;
  87             return SignExtendNode.create(other.getValue(), other.getInputBits(), getResultBits());
  88         } else if (forValue instanceof ZeroExtendNode) {
  89             ZeroExtendNode other = (ZeroExtendNode) forValue;
  90             if (other.getResultBits() > other.getInputBits()) {
  91                 // sxxx -(zero-extend)-> 0000 sxxx -(sign-extend)-> 00000000 0000sxxx
  92                 // ==> sxxx -(zero-extend)-> 00000000 0000sxxx
  93                 return ZeroExtendNode.create(other.getValue(), other.getInputBits(), getResultBits());
  94             }
  95         }
  96 
  97         if (forValue.stamp() instanceof IntegerStamp) {
  98             IntegerStamp inputStamp = (IntegerStamp) forValue.stamp();
  99             if ((inputStamp.upMask() & (1L << (getInputBits() - 1))) == 0L) {
 100                 // 0xxx -(sign-extend)-> 0000 0xxx
 101                 // ==> 0xxx -(zero-extend)-> 0000 0xxx
 102                 return ZeroExtendNode.create(forValue, getInputBits(), getResultBits());
 103             }
 104         }
 105 
 106         return this;
 107     }
 108 
 109     @Override
 110     public void generate(NodeLIRBuilderTool nodeValueMap, ArithmeticLIRGeneratorTool gen) {
 111         nodeValueMap.setResult(this, gen.emitSignExtend(nodeValueMap.operand(getValue()), getInputBits(), getResultBits()));
 112     }
 113 
 114     @Override
 115     public boolean mayNullCheckSkipConversion() {
 116         return true;
 117     }
 118 }