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
19namespace llvm {
20
21class raw_ostream;
22class BranchProbability;
23
24// This class represents Block Frequency as a 64-bit value.
25class BlockFrequency {
26
27  uint64_t Frequency;
28  static const int64_t ENTRY_FREQ = 1 << 14;
29
30  /// \brief Scale the given BlockFrequency by N/D. Return the remainder from
31  /// the division by D. Upon overflow, the routine will saturate and
32  /// additionally will return the remainder set to D.
33  uint32_t scale(uint32_t N, uint32_t D);
34
35public:
36  BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
37
38  /// \brief Returns the frequency of the entry block of the function.
39  static uint64_t getEntryFrequency() { return ENTRY_FREQ; }
40
41  /// \brief Returns the maximum possible frequency, the saturation value.
42  static uint64_t getMaxFrequency() { return -1ULL; }
43
44  /// \brief Returns the frequency as a fixpoint number scaled by the entry
45  /// frequency.
46  uint64_t getFrequency() const { return Frequency; }
47
48  /// \brief Multiplies with a branch probability. The computation will never
49  /// overflow.
50  BlockFrequency &operator*=(const BranchProbability &Prob);
51  const BlockFrequency operator*(const BranchProbability &Prob) const;
52
53  /// \brief Divide by a non-zero branch probability using saturating
54  /// arithmetic.
55  BlockFrequency &operator/=(const BranchProbability &Prob);
56  BlockFrequency operator/(const BranchProbability &Prob) const;
57
58  /// \brief Adds another block frequency using saturating arithmetic.
59  BlockFrequency &operator+=(const BlockFrequency &Freq);
60  const BlockFrequency operator+(const BlockFrequency &Freq) const;
61
62  /// \brief Scale the given BlockFrequency by N/D. Return the remainder from
63  /// the division by D. Upon overflow, the routine will saturate.
64  uint32_t scale(const BranchProbability &Prob);
65
66  bool operator<(const BlockFrequency &RHS) const {
67    return Frequency < RHS.Frequency;
68  }
69
70  bool operator<=(const BlockFrequency &RHS) const {
71    return Frequency <= RHS.Frequency;
72  }
73
74  bool operator>(const BlockFrequency &RHS) const {
75    return Frequency > RHS.Frequency;
76  }
77
78  bool operator>=(const BlockFrequency &RHS) const {
79    return Frequency >= RHS.Frequency;
80  }
81
82  void print(raw_ostream &OS) const;
83};
84
85raw_ostream &operator<<(raw_ostream &OS, const BlockFrequency &Freq);
86
87}
88
89#endif
90