1//===- BranchProbability.h - Branch Probability 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// Definition of BranchProbability shared by IR and Machine Instructions.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_BRANCHPROBABILITY_H
15#define LLVM_SUPPORT_BRANCHPROBABILITY_H
16
17#include "llvm/Support/DataTypes.h"
18#include <cassert>
19
20namespace llvm {
21
22class raw_ostream;
23
24// This class represents Branch Probability as a non-negative fraction.
25class BranchProbability {
26  // Numerator
27  uint32_t N;
28
29  // Denominator
30  uint32_t D;
31
32public:
33  BranchProbability(uint32_t n, uint32_t d) : N(n), D(d) {
34    assert(d > 0 && "Denomiator cannot be 0!");
35    assert(n <= d && "Probability cannot be bigger than 1!");
36  }
37
38  static BranchProbability getZero() { return BranchProbability(0, 1); }
39  static BranchProbability getOne() { return BranchProbability(1, 1); }
40
41  uint32_t getNumerator() const { return N; }
42  uint32_t getDenominator() const { return D; }
43
44  // Return (1 - Probability).
45  BranchProbability getCompl() const {
46    return BranchProbability(D - N, D);
47  }
48
49  void print(raw_ostream &OS) const;
50
51  void dump() const;
52
53  bool operator==(BranchProbability RHS) const {
54    return (uint64_t)N * RHS.D == (uint64_t)D * RHS.N;
55  }
56  bool operator!=(BranchProbability RHS) const {
57    return !(*this == RHS);
58  }
59  bool operator<(BranchProbability RHS) const {
60    return (uint64_t)N * RHS.D < (uint64_t)D * RHS.N;
61  }
62  bool operator>(BranchProbability RHS) const {
63    return RHS < *this;
64  }
65  bool operator<=(BranchProbability RHS) const {
66    return (uint64_t)N * RHS.D <= (uint64_t)D * RHS.N;
67  }
68  bool operator>=(BranchProbability RHS) const {
69    return RHS <= *this;
70  }
71};
72
73raw_ostream &operator<<(raw_ostream &OS, const BranchProbability &Prob);
74
75}
76
77#endif
78