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.loop;
  24 
  25 import static org.graalvm.compiler.loop.MathUtil.add;
  26 import static org.graalvm.compiler.loop.MathUtil.mul;
  27 import static org.graalvm.compiler.loop.MathUtil.sub;
  28 
  29 import org.graalvm.compiler.core.common.type.IntegerStamp;
  30 import org.graalvm.compiler.core.common.type.Stamp;
  31 import org.graalvm.compiler.debug.GraalError;
  32 import org.graalvm.compiler.nodes.ConstantNode;
  33 import org.graalvm.compiler.nodes.StructuredGraph;
  34 import org.graalvm.compiler.nodes.ValueNode;
  35 import org.graalvm.compiler.nodes.ValuePhiNode;
  36 import org.graalvm.compiler.nodes.calc.AddNode;
  37 import org.graalvm.compiler.nodes.calc.BinaryArithmeticNode;
  38 import org.graalvm.compiler.nodes.calc.IntegerConvertNode;
  39 import org.graalvm.compiler.nodes.calc.NegateNode;
  40 import org.graalvm.compiler.nodes.calc.SubNode;
  41 
  42 public class BasicInductionVariable extends InductionVariable {
  43 
  44     private final ValuePhiNode phi;
  45     private final ValueNode init;
  46     private ValueNode rawStride;
  47     private BinaryArithmeticNode<?> op;
  48 
  49     public BasicInductionVariable(LoopEx loop, ValuePhiNode phi, ValueNode init, ValueNode rawStride, BinaryArithmeticNode<?> op) {
  50         super(loop);
  51         this.phi = phi;
  52         this.init = init;
  53         this.rawStride = rawStride;
  54         this.op = op;
  55     }
  56 
  57     @Override
  58     public StructuredGraph graph() {
  59         return phi.graph();
  60     }
  61 
  62     public BinaryArithmeticNode<?> getOp() {
  63         return op;
  64     }
  65 
  66     public void setOP(BinaryArithmeticNode<?> newOp) {
  67         rawStride = newOp.getY();
  68         op = newOp;
  69     }
  70 
  71     @Override
  72     public Direction direction() {
  73         Stamp stamp = rawStride.stamp();
  74         if (stamp instanceof IntegerStamp) {
  75             IntegerStamp integerStamp = (IntegerStamp) stamp;
  76             Direction dir = null;
  77             if (integerStamp.isStrictlyPositive()) {
  78                 dir = Direction.Up;
  79             } else if (integerStamp.isStrictlyNegative()) {
  80                 dir = Direction.Down;
  81             }
  82             if (dir != null) {
  83                 if (op instanceof AddNode) {
  84                     return dir;
  85                 } else {
  86                     assert op instanceof SubNode;
  87                     return dir.opposite();
  88                 }
  89             }
  90         }
  91         return null;
  92     }
  93 
  94     @Override
  95     public ValuePhiNode valueNode() {
  96         return phi;
  97     }
  98 
  99     @Override
 100     public ValueNode initNode() {
 101         return init;
 102     }
 103 
 104     @Override
 105     public ValueNode strideNode() {
 106         if (op instanceof AddNode) {
 107             return rawStride;
 108         }
 109         if (op instanceof SubNode) {
 110             return graph().unique(new NegateNode(rawStride));
 111         }
 112         throw GraalError.shouldNotReachHere();
 113     }
 114 
 115     @Override
 116     public boolean isConstantInit() {
 117         return init.isConstant();
 118     }
 119 
 120     @Override
 121     public boolean isConstantStride() {
 122         return rawStride.isConstant();
 123     }
 124 
 125     @Override
 126     public long constantInit() {
 127         return init.asJavaConstant().asLong();
 128     }
 129 
 130     @Override
 131     public long constantStride() {
 132         if (op instanceof AddNode) {
 133             return rawStride.asJavaConstant().asLong();
 134         }
 135         if (op instanceof SubNode) {
 136             return -rawStride.asJavaConstant().asLong();
 137         }
 138         throw GraalError.shouldNotReachHere();
 139     }
 140 
 141     @Override
 142     public ValueNode extremumNode(boolean assumePositiveTripCount, Stamp stamp) {
 143         Stamp fromStamp = phi.stamp();
 144         StructuredGraph graph = graph();
 145         ValueNode stride = strideNode();
 146         ValueNode initNode = this.initNode();
 147         if (!fromStamp.isCompatible(stamp)) {
 148             stride = IntegerConvertNode.convert(stride, stamp, graph());
 149             initNode = IntegerConvertNode.convert(initNode, stamp, graph());
 150         }
 151         ValueNode maxTripCount = loop.counted().maxTripCountNode(assumePositiveTripCount);
 152         if (!maxTripCount.stamp().isCompatible(stamp)) {
 153             maxTripCount = IntegerConvertNode.convert(maxTripCount, stamp, graph());
 154         }
 155         return add(graph, mul(graph, stride, sub(graph, maxTripCount, ConstantNode.forIntegerStamp(stamp, 1, graph))), initNode);
 156     }
 157 
 158     @Override
 159     public ValueNode exitValueNode() {
 160         Stamp stamp = phi.stamp();
 161         ValueNode maxTripCount = loop.counted().maxTripCountNode(false);
 162         if (!maxTripCount.stamp().isCompatible(stamp)) {
 163             maxTripCount = IntegerConvertNode.convert(maxTripCount, stamp, graph());
 164         }
 165         return add(graph(), mul(graph(), strideNode(), maxTripCount), initNode());
 166     }
 167 
 168     @Override
 169     public boolean isConstantExtremum() {
 170         return isConstantInit() && isConstantStride() && loop.counted().isConstantMaxTripCount();
 171     }
 172 
 173     @Override
 174     public long constantExtremum() {
 175         return constantStride() * (loop.counted().constantMaxTripCount() - 1) + constantInit();
 176     }
 177 
 178     @Override
 179     public void deleteUnusedNodes() {
 180     }
 181 
 182     @Override
 183     public String toString() {
 184         return String.format("BasicInductionVariable %s %s %s %s", initNode(), phi, op.getNodeClass().shortName(), strideNode());
 185     }
 186 }