include/llvm/Support/BlockFrequency.h

   1 //===-------- BlockFrequency.h - Block Frequency Wrapper --------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements Block Frequency class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_SUPPORT_BLOCKFREQUENCY_H
  14 #define LLVM_SUPPORT_BLOCKFREQUENCY_H
  15
  16 #include "llvm/Support/BranchProbability.h"
  17 #include "llvm/Support/DataTypes.h"
  18
  19 namespace llvm {
  20
  21 class raw_ostream;
  22
  23 // This class represents Block Frequency as a 64-bit value.
  24 class BlockFrequency {
  25   uint64_t Frequency;
  26
  27 public:
  28   BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
  29
  30   /// Returns the maximum possible frequency, the saturation value.
  31   static uint64_t getMaxFrequency() { return -1ULL; }
  32
  33   /// Returns the frequency as a fixpoint number scaled by the entry
  34   /// frequency.
  35   uint64_t getFrequency() const { return Frequency; }
  36
  37   /// Multiplies with a branch probability. The computation will never
  38   /// overflow.
  39   BlockFrequency &operator*=(BranchProbability Prob);
  40   BlockFrequency operator*(BranchProbability Prob) const;
  41
  42   /// Divide by a non-zero branch probability using saturating
  43   /// arithmetic.
  44   BlockFrequency &operator/=(BranchProbability Prob);
  45   BlockFrequency operator/(BranchProbability Prob) const;
  46
  47   /// Adds another block frequency using saturating arithmetic.
  48   BlockFrequency &operator+=(BlockFrequency Freq);
  49   BlockFrequency operator+(BlockFrequency Freq) const;
  50
  51   /// Subtracts another block frequency using saturating arithmetic.
  52   BlockFrequency &operator-=(BlockFrequency Freq);
  53   BlockFrequency operator-(BlockFrequency Freq) const;
  54
  55   /// Shift block frequency to the right by count digits saturating to 1.
  56   BlockFrequency &operator>>=(const unsigned count);
  57
  58   bool operator<(BlockFrequency RHS) const {
  59     return Frequency < RHS.Frequency;
  60   }
  61
  62   bool operator<=(BlockFrequency RHS) const {
  63     return Frequency <= RHS.Frequency;
  64   }
  65
  66   bool operator>(BlockFrequency RHS) const {
  67     return Frequency > RHS.Frequency;
  68   }
  69
  70   bool operator>=(BlockFrequency RHS) const {
  71     return Frequency >= RHS.Frequency;
  72   }
  73
  74   bool operator==(BlockFrequency RHS) const {
  75     return Frequency == RHS.Frequency;
  76   }
  77 };
  78
  79 }
  80
  81 #endif