Mercurial > hg > graal-compiler
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/BranchProbabilityNode.java @ 16919:0fe4732e5181
made use of generated Node classes predicated on value of graal.useGeneratedNodes system property (default is false)
author | Doug Simon <doug.simon@oracle.com> |
---|---|
date | Mon, 25 Aug 2014 13:45:12 +0200 |
parents | f90dcdbbb75e |
children | 845e881ce054 |
line wrap: on
line source
/* * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.graal.nodes.extended; import com.oracle.graal.compiler.common.*; import com.oracle.graal.compiler.common.calc.*; import com.oracle.graal.graph.spi.*; import com.oracle.graal.nodeinfo.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.calc.*; import com.oracle.graal.nodes.spi.*; /** * Instances of this node class will look for a preceding if node and put the given probability into * the if node's taken probability. Then the branch probability node will be removed. This node is * intended primarily for snippets, so that they can define their fast and slow paths. */ @NodeInfo public class BranchProbabilityNode extends FloatingNode implements Simplifiable, Lowerable { public static final double LIKELY_PROBABILITY = 0.6; public static final double NOT_LIKELY_PROBABILITY = 1 - LIKELY_PROBABILITY; public static final double FREQUENT_PROBABILITY = 0.9; public static final double NOT_FREQUENT_PROBABILITY = 1 - FREQUENT_PROBABILITY; public static final double FAST_PATH_PROBABILITY = 0.99; public static final double SLOW_PATH_PROBABILITY = 1 - FAST_PATH_PROBABILITY; public static final double VERY_FAST_PATH_PROBABILITY = 0.999; public static final double VERY_SLOW_PATH_PROBABILITY = 1 - VERY_FAST_PATH_PROBABILITY; @Input ValueNode probability; @Input ValueNode condition; public static BranchProbabilityNode create(ValueNode probability, ValueNode condition) { return USE_GENERATED_NODES ? new BranchProbabilityNodeGen(probability, condition) : new BranchProbabilityNode(probability, condition); } BranchProbabilityNode(ValueNode probability, ValueNode condition) { super(condition.stamp()); this.probability = probability; this.condition = condition; } public ValueNode getProbability() { return probability; } public ValueNode getCondition() { return condition; } @Override public void simplify(SimplifierTool tool) { if (probability.isConstant()) { double probabilityValue = probability.asConstant().asDouble(); if (probabilityValue < 0.0) { throw new GraalInternalError("A negative probability of " + probabilityValue + " is not allowed!"); } else if (probabilityValue > 1.0) { throw new GraalInternalError("A probability of more than 1.0 (" + probabilityValue + ") is not allowed!"); } boolean couldSet = false; for (IntegerEqualsNode node : this.usages().filter(IntegerEqualsNode.class)) { if (node.condition() == Condition.EQ) { ValueNode other = node.getX(); if (node.getX() == this) { other = node.getY(); } if (other.isConstant()) { double probabilityToSet = probabilityValue; if (other.asConstant().asInt() == 0) { probabilityToSet = 1.0 - probabilityToSet; } for (IfNode ifNodeUsages : node.usages().filter(IfNode.class)) { couldSet = true; ifNodeUsages.setTrueSuccessorProbability(probabilityToSet); } } } } if (couldSet) { replaceAndDelete(condition); tool.addToWorkList(condition.usages()); } else { if (!isSubstitutionGraph()) { throw new GraalInternalError("Wrong usage of branch probability injection!"); } } } } private boolean isSubstitutionGraph() { return usages().count() == 1 && usages().first() instanceof ReturnNode; } /** * This intrinsic should only be used for the condition of an if statement. The parameter * condition should also only denote a simple condition and not a combined condition involving * && or || operators. It injects the probability of the condition into the if * statement. * * @param probability the probability that the given condition is true as a double value between * 0.0 and 1.0. * @param condition the simple condition without any && or || operators * @return the condition */ @NodeIntrinsic public static boolean probability(double probability, boolean condition) { assert probability >= 0.0 && probability <= 1.0; return condition; } @Override public void lower(LoweringTool tool) { throw new GraalInternalError("Branch probability could not be injected, because the probability value did not reduce to a constant value."); } }