1 /*
   2  * Copyright (c) 2013, 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.aarch64;
  24 
  25 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_6;
  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.aarch64.AArch64ArithmeticLIRGeneratorTool;
  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 @NodeInfo(cycles = CYCLES_6, size = SIZE_1)
  46 public final class AArch64CountLeadingZerosNode extends UnaryNode implements ArithmeticLIRLowerable {
  47 
  48     public static final NodeClass<AArch64CountLeadingZerosNode> TYPE = NodeClass.create(AArch64CountLeadingZerosNode.class);
  49 
  50     public AArch64CountLeadingZerosNode(ValueNode value) {
  51         super(TYPE, computeStamp(value.stamp(), value), value);
  52     }
  53 
  54     @Override
  55     public Stamp foldStamp(Stamp newStamp) {
  56         return computeStamp(newStamp, getValue());
  57     }
  58 
  59     private static Stamp computeStamp(Stamp newStamp, ValueNode theValue) {
  60         assert newStamp.isCompatible(theValue.stamp());
  61         assert theValue.getStackKind() == JavaKind.Int || theValue.getStackKind() == JavaKind.Long;
  62         return StampTool.stampForLeadingZeros((IntegerStamp) newStamp);
  63     }
  64 
  65     public static ValueNode tryFold(ValueNode value) {
  66         if (value.isConstant()) {
  67             JavaConstant c = value.asJavaConstant();
  68             if (value.getStackKind() == JavaKind.Int) {
  69                 return ConstantNode.forInt(Integer.numberOfLeadingZeros(c.asInt()));
  70             } else {
  71                 return ConstantNode.forInt(Long.numberOfLeadingZeros(c.asLong()));
  72             }
  73         }
  74         return null;
  75     }
  76 
  77     @Override
  78     public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) {
  79         ValueNode folded = tryFold(forValue);
  80         return folded != null ? folded : this;
  81     }
  82 
  83     @Override
  84     public void generate(NodeLIRBuilderTool builder, ArithmeticLIRGeneratorTool gen) {
  85         builder.setResult(this, ((AArch64ArithmeticLIRGeneratorTool) gen).emitCountLeadingZeros(builder.operand(getValue())));
  86     }
  87 }