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:
Frequency(Freq)28   BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
29 
30   /// Returns the maximum possible frequency, the saturation value.
getMaxFrequency()31   static uint64_t getMaxFrequency() { return -1ULL; }
32 
33   /// Returns the frequency as a fixpoint number scaled by the entry
34   /// frequency.
getFrequency()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