/* * This file is part of the Jikes RVM project (http://jikesrvm.org). * * This file is licensed to You under the Eclipse Public License (EPL); * You may not use this file except in compliance with the License. You * may obtain a copy of the License at * * http://www.opensource.org/licenses/eclipse-1.0.php * * See the COPYRIGHT.txt file distributed with this work for information * regarding copyright ownership. */ package org.jikesrvm.compilers.opt.ir.operand; /** * * @see Operand */ public final class BranchProfileOperand extends Operand { public float takenProbability; public static final float ALWAYS = 1f; public static final float LIKELY = .99f; public static final float UNLIKELY = 1f - LIKELY; public static final float NEVER = 1f - ALWAYS; public BranchProfileOperand(float takenProbability) { this.takenProbability = takenProbability; } public BranchProfileOperand() { this.takenProbability = 0.5f; } public static BranchProfileOperand always() { return new BranchProfileOperand(ALWAYS); } public static BranchProfileOperand likely() { return new BranchProfileOperand(LIKELY); } public static BranchProfileOperand unlikely() { return new BranchProfileOperand(UNLIKELY); } public static BranchProfileOperand never() { return new BranchProfileOperand(NEVER); } /** * Returns a copy of this branch operand. * * @return a copy of this operand */ @Override public Operand copy() { return new BranchProfileOperand(takenProbability); } /** * Flip the probability (p = 1 - p) * * @return this */ public BranchProfileOperand flip() { takenProbability = 1f - takenProbability; return this; } @Override public boolean similar(Operand op) { return (op instanceof BranchProfileOperand) && (takenProbability == ((BranchProfileOperand) op).takenProbability); } /** * Returns the string representation of this operand. * * @return a string representation of this operand. */ @Override public String toString() { return "Probability: " + takenProbability; } }