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 //===- BranchProbability.h - Branch Probability Wrapper ---------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // Definition of BranchProbability shared by IR and Machine Instructions. // //===----------------------------------------------------------------------===// #ifndef LLVM_SUPPORT_BRANCHPROBABILITY_H #define LLVM_SUPPORT_BRANCHPROBABILITY_H #include "llvm/Support/DataTypes.h" #include namespace llvm { class raw_ostream; // This class represents Branch Probability as a non-negative fraction. class BranchProbability { // Numerator uint32_t N; // Denominator uint32_t D; public: BranchProbability(uint32_t n, uint32_t d) : N(n), D(d) { assert(d > 0 && "Denomiator cannot be 0!"); assert(n <= d && "Probability cannot be bigger than 1!"); } static BranchProbability getZero() { return BranchProbability(0, 1); } static BranchProbability getOne() { return BranchProbability(1, 1); } uint32_t getNumerator() const { return N; } uint32_t getDenominator() const { return D; } // Return (1 - Probability). BranchProbability getCompl() const { return BranchProbability(D - N, D); } raw_ostream &print(raw_ostream &OS) const; void dump() const; /// \brief Scale a large integer. /// /// Scales \c Num. Guarantees full precision. Returns the floor of the /// result. /// /// \return \c Num times \c this. uint64_t scale(uint64_t Num) const; /// \brief Scale a large integer by the inverse. /// /// Scales \c Num by the inverse of \c this. Guarantees full precision. /// Returns the floor of the result. /// /// \return \c Num divided by \c this. uint64_t scaleByInverse(uint64_t Num) const; bool operator==(BranchProbability RHS) const { return (uint64_t)N * RHS.D == (uint64_t)D * RHS.N; } bool operator!=(BranchProbability RHS) const { return !(*this == RHS); } bool operator<(BranchProbability RHS) const { return (uint64_t)N * RHS.D < (uint64_t)D * RHS.N; } bool operator>(BranchProbability RHS) const { return RHS < *this; } bool operator<=(BranchProbability RHS) const { return !(RHS < *this); } bool operator>=(BranchProbability RHS) const { return !(*this < RHS); } }; inline raw_ostream &operator<<(raw_ostream &OS, const BranchProbability &Prob) { return Prob.print(OS); } } #endif