AMD64CountLeadingZerosNode.java revision 12657:6ef01bd40ce2
1219185Sadrian/* 2219185Sadrian * Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved. 3219185Sadrian * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4219185Sadrian * 5219185Sadrian * This code is free software; you can redistribute it and/or modify it 6219185Sadrian * under the terms of the GNU General Public License version 2 only, as 7219185Sadrian * published by the Free Software Foundation. 8219185Sadrian * 9219185Sadrian * This code is distributed in the hope that it will be useful, but WITHOUT 10219185Sadrian * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11219185Sadrian * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12219185Sadrian * version 2 for more details (a copy is included in the LICENSE file that 13219185Sadrian * accompanied this code). 14219185Sadrian * 15219185Sadrian * You should have received a copy of the GNU General Public License version 16219185Sadrian * 2 along with this work; if not, write to the Free Software Foundation, 17219185Sadrian * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18219185Sadrian * 19219185Sadrian * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20219185Sadrian * or visit www.oracle.com if you need additional information or have any 21219185Sadrian * questions. 22219185Sadrian */ 23219185Sadrianpackage org.graalvm.compiler.replacements.amd64; 24219185Sadrian 25219185Sadrianimport static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_3; 26219185Sadrianimport static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1; 27219185Sadrian 28219185Sadrianimport org.graalvm.compiler.core.common.type.IntegerStamp; 29219185Sadrianimport org.graalvm.compiler.core.common.type.Stamp; 30219185Sadrianimport org.graalvm.compiler.graph.NodeClass; 31219185Sadrianimport org.graalvm.compiler.graph.spi.CanonicalizerTool; 32219185Sadrianimport org.graalvm.compiler.lir.amd64.AMD64ArithmeticLIRGeneratorTool; 33219185Sadrianimport org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool; 34219185Sadrianimport org.graalvm.compiler.nodeinfo.NodeInfo; 35219185Sadrianimport org.graalvm.compiler.nodes.ConstantNode; 36219185Sadrianimport org.graalvm.compiler.nodes.ValueNode; 37219185Sadrianimport org.graalvm.compiler.nodes.calc.UnaryNode; 38219185Sadrianimport org.graalvm.compiler.nodes.spi.ArithmeticLIRLowerable; 39219185Sadrianimport org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; 40227357Sadrianimport org.graalvm.compiler.nodes.type.StampTool; 41227357Sadrian 42219185Sadrianimport jdk.vm.ci.meta.JavaConstant; 43219185Sadrianimport jdk.vm.ci.meta.JavaKind; 44 45/** 46 * Count the number of leading zeros using the {@code lzcntq} or {@code lzcntl} instructions. 47 */ 48@NodeInfo(cycles = CYCLES_3, size = SIZE_1) 49public final class AMD64CountLeadingZerosNode extends UnaryNode implements ArithmeticLIRLowerable { 50 public static final NodeClass<AMD64CountLeadingZerosNode> TYPE = NodeClass.create(AMD64CountLeadingZerosNode.class); 51 52 public AMD64CountLeadingZerosNode(ValueNode value) { 53 super(TYPE, computeStamp(value.stamp(), value), value); 54 assert value.getStackKind() == JavaKind.Int || value.getStackKind() == JavaKind.Long; 55 } 56 57 @Override 58 public Stamp foldStamp(Stamp newStamp) { 59 return computeStamp(newStamp, getValue()); 60 } 61 62 private static Stamp computeStamp(Stamp newStamp, ValueNode theValue) { 63 assert newStamp.isCompatible(theValue.stamp()); 64 assert theValue.getStackKind() == JavaKind.Int || theValue.getStackKind() == JavaKind.Long; 65 return StampTool.stampForLeadingZeros((IntegerStamp) newStamp); 66 } 67 68 public static ValueNode tryFold(ValueNode value) { 69 if (value.isConstant()) { 70 JavaConstant c = value.asJavaConstant(); 71 if (value.getStackKind() == JavaKind.Int) { 72 return ConstantNode.forInt(Integer.numberOfLeadingZeros(c.asInt())); 73 } else { 74 return ConstantNode.forInt(Long.numberOfLeadingZeros(c.asLong())); 75 } 76 } 77 return null; 78 } 79 80 @Override 81 public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) { 82 ValueNode folded = tryFold(forValue); 83 return folded != null ? folded : this; 84 } 85 86 @Override 87 public void generate(NodeLIRBuilderTool builder, ArithmeticLIRGeneratorTool gen) { 88 builder.setResult(this, ((AMD64ArithmeticLIRGeneratorTool) gen).emitCountLeadingZeros(builder.operand(getValue()))); 89 } 90} 91