1 //===- BranchProbability.h - Branch Probability Wrapper ---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Definition of BranchProbability shared by IR and Machine Instructions.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SUPPORT_BRANCHPROBABILITY_H
15 #define LLVM_SUPPORT_BRANCHPROBABILITY_H
17 #include "llvm/Support/DataTypes.h"
24 // This class represents Branch Probability as a non-negative fraction.
25 class BranchProbability {
32 int64_t compare(BranchProbability RHS) const {
33 return (uint64_t)N * RHS.D - (uint64_t)D * RHS.N;
37 BranchProbability(uint32_t n, uint32_t d) : N(n), D(d) {
38 assert(d > 0 && "Denomiator cannot be 0!");
39 assert(n <= d && "Probability cannot be bigger than 1!");
42 static BranchProbability getZero() { return BranchProbability(0, 1); }
43 static BranchProbability getOne() { return BranchProbability(1, 1); }
45 uint32_t getNumerator() const { return N; }
46 uint32_t getDenominator() const { return D; }
48 // Return (1 - Probability).
49 BranchProbability getCompl() {
50 return BranchProbability(D - N, D);
53 void print(raw_ostream &OS) const;
57 bool operator==(BranchProbability RHS) const { return compare(RHS) == 0; }
58 bool operator!=(BranchProbability RHS) const { return compare(RHS) != 0; }
59 bool operator< (BranchProbability RHS) const { return compare(RHS) < 0; }
60 bool operator> (BranchProbability RHS) const { return compare(RHS) > 0; }
61 bool operator<=(BranchProbability RHS) const { return compare(RHS) <= 0; }
62 bool operator>=(BranchProbability RHS) const { return compare(RHS) >= 0; }
65 raw_ostream &operator<<(raw_ostream &OS, const BranchProbability &Prob);