1 /* 2 * Copyright (c) 2012, 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.replacements.amd64; 24 25 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_3; 26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1; 27 28 import org.graalvm.compiler.core.common.type.IntegerStamp; 29 import org.graalvm.compiler.core.common.type.Stamp; 30 import org.graalvm.compiler.graph.NodeClass; 31 import org.graalvm.compiler.graph.spi.CanonicalizerTool; 32 import org.graalvm.compiler.lir.amd64.AMD64ArithmeticLIRGeneratorTool; 33 import org.graalvm.compiler.lir.gen.ArithmeticLIRGeneratorTool; 34 import org.graalvm.compiler.nodeinfo.NodeInfo; 35 import org.graalvm.compiler.nodes.ConstantNode; 36 import org.graalvm.compiler.nodes.ValueNode; 37 import org.graalvm.compiler.nodes.calc.UnaryNode; 38 import org.graalvm.compiler.nodes.spi.ArithmeticLIRLowerable; 39 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; 40 import org.graalvm.compiler.nodes.type.StampTool; 41 42 import jdk.vm.ci.meta.JavaConstant; 43 import jdk.vm.ci.meta.JavaKind; 44 45 /** 46 * Count the number of trailing zeros using the {@code tzcntq} or {@code tzcntl} instructions. 47 */ 48 @NodeInfo(cycles = CYCLES_3, size = SIZE_1) 49 public final class AMD64CountTrailingZerosNode extends UnaryNode implements ArithmeticLIRLowerable { 50 public static final NodeClass<AMD64CountTrailingZerosNode> TYPE = NodeClass.create(AMD64CountTrailingZerosNode.class); 51 52 public AMD64CountTrailingZerosNode(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 static Stamp computeStamp(Stamp newStamp, ValueNode value) { 63 assert newStamp.isCompatible(value.stamp()); 64 IntegerStamp valueStamp = (IntegerStamp) newStamp; 65 return StampTool.stampForTrailingZeros(valueStamp); 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.numberOfTrailingZeros(c.asInt())); 73 } else { 74 return ConstantNode.forInt(Long.numberOfTrailingZeros(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).emitCountTrailingZeros(builder.operand(getValue()))); 89 } 90 }