--- /dev/null 2016-05-31 09:42:47.975716356 -0700 +++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/extended/BranchProbabilityNode.java 2016-12-09 00:55:30.915252348 -0800 @@ -0,0 +1,156 @@ +/* + * 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 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."); + } +}