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      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
     82