src/llvm/include/llvm/Support/BlockFrequency.h

   1 //===-------- BlockFrequency.h - Block Frequency Wrapper --------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements Block Frequency class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_SUPPORT_BLOCKFREQUENCY_H
  15 #define LLVM_SUPPORT_BLOCKFREQUENCY_H
  16
  17 #include "llvm/Support/DataTypes.h"
  18
  19 namespace llvm {
  20
  21 class raw_ostream;
  22 class BranchProbability;
  23
  24 // This class represents Block Frequency as a 64-bit value.
  25 class BlockFrequency {
  26   uint64_t Frequency;
  27
  28 public:
  29   BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
  30
  31   /// \brief Returns the maximum possible frequency, the saturation value.
  32   static uint64_t getMaxFrequency() { return -1ULL; }
  33
  34   /// \brief Returns the frequency as a fixpoint number scaled by the entry
  35   /// frequency.
  36   uint64_t getFrequency() const { return Frequency; }
  37
  38   /// \brief Multiplies with a branch probability. The computation will never
  39   /// overflow.
  40   BlockFrequency &operator*=(const BranchProbability &Prob);
  41   const BlockFrequency operator*(const BranchProbability &Prob) const;
  42
  43   /// \brief Divide by a non-zero branch probability using saturating
  44   /// arithmetic.
  45   BlockFrequency &operator/=(const BranchProbability &Prob);
  46   BlockFrequency operator/(const BranchProbability &Prob) const;
  47
  48   /// \brief Adds another block frequency using saturating arithmetic.
  49   BlockFrequency &operator+=(const BlockFrequency &Freq);
  50   const BlockFrequency operator+(const BlockFrequency &Freq) const;
  51
  52   /// \brief Shift block frequency to the right by count digits saturating to 1.
  53   BlockFrequency &operator>>=(const unsigned count);
  54
  55   bool operator<(const BlockFrequency &RHS) const {
  56     return Frequency < RHS.Frequency;
  57   }
  58
  59   bool operator<=(const BlockFrequency &RHS) const {
  60     return Frequency <= RHS.Frequency;
  61   }
  62
  63   bool operator>(const BlockFrequency &RHS) const {
  64     return Frequency > RHS.Frequency;
  65   }
  66
  67   bool operator>=(const BlockFrequency &RHS) const {
  68     return Frequency >= RHS.Frequency;
  69   }
  70 };
  71
  72 }
  73
  74 #endif