| /* |
| * Copyright (c) 2012, 2014, 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 org.graalvm.compiler.nodes.extended; |
| |
| import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0; |
| import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0; |
| |
| import org.graalvm.compiler.core.common.calc.Condition; |
| import org.graalvm.compiler.debug.GraalError; |
| import org.graalvm.compiler.graph.NodeClass; |
| import org.graalvm.compiler.graph.iterators.NodePredicates; |
| import org.graalvm.compiler.graph.spi.Simplifiable; |
| import org.graalvm.compiler.graph.spi.SimplifierTool; |
| import org.graalvm.compiler.nodeinfo.NodeInfo; |
| import org.graalvm.compiler.nodes.FixedGuardNode; |
| import org.graalvm.compiler.nodes.IfNode; |
| import org.graalvm.compiler.nodes.ReturnNode; |
| import org.graalvm.compiler.nodes.ValueNode; |
| import org.graalvm.compiler.nodes.calc.ConditionalNode; |
| import org.graalvm.compiler.nodes.calc.FloatingNode; |
| import org.graalvm.compiler.nodes.calc.IntegerEqualsNode; |
| import org.graalvm.compiler.nodes.spi.Lowerable; |
| import org.graalvm.compiler.nodes.spi.LoweringTool; |
| |
| /** |
| * 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(cycles = CYCLES_0, cyclesRationale = "Artificial Node", size = SIZE_0) |
| public final class BranchProbabilityNode extends FloatingNode implements Simplifiable, Lowerable { |
| |
| public static final NodeClass<BranchProbabilityNode> TYPE = NodeClass.create(BranchProbabilityNode.class); |
| 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 BranchProbabilityNode(ValueNode probability, ValueNode condition) { |
| super(TYPE, 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.asJavaConstant().asDouble(); |
| if (probabilityValue < 0.0) { |
| throw new GraalError("A negative probability of " + probabilityValue + " is not allowed!"); |
| } else if (probabilityValue > 1.0) { |
| throw new GraalError("A probability of more than 1.0 (" + probabilityValue + ") is not allowed!"); |
| } else if (Double.isNaN(probabilityValue)) { |
| /* |
| * We allow NaN if the node is in unreachable code that will eventually fall away, |
| * or else an error will be thrown during lowering since we keep the node around. |
| */ |
| return; |
| } |
| boolean usageFound = 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.asJavaConstant().asInt() == 0) { |
| probabilityToSet = 1.0 - probabilityToSet; |
| } |
| for (IfNode ifNodeUsages : node.usages().filter(IfNode.class)) { |
| usageFound = true; |
| ifNodeUsages.setTrueSuccessorProbability(probabilityToSet); |
| } |
| if (!usageFound) { |
| usageFound = node.usages().filter(NodePredicates.isA(FixedGuardNode.class).or(ConditionalNode.class)).isNotEmpty(); |
| } |
| } |
| } |
| } |
| if (usageFound) { |
| ValueNode currentCondition = condition; |
| replaceAndDelete(currentCondition); |
| if (tool != null) { |
| tool.addToWorkList(currentCondition.usages()); |
| } |
| } else { |
| if (!isSubstitutionGraph()) { |
| throw new GraalError("Wrong usage of branch probability injection!"); |
| } |
| } |
| } |
| } |
| |
| private boolean isSubstitutionGraph() { |
| return getUsageCount() == 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 native boolean probability(double probability, boolean condition); |
| |
| @Override |
| public void lower(LoweringTool tool) { |
| throw new GraalError("Branch probability could not be injected, because the probability value did not reduce to a constant value."); |
| } |
| } |
