| //===- 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 <cassert> |
| |
| 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 |