BlockFrequency.cpp revision 1.1.1.1 
1//====--------------- lib/Support/BlockFrequency.cpp -----------*- 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#include "llvm/Support/BlockFrequency.h"
14#include <cassert>
15
16using namespace llvm;
17
18BlockFrequency &BlockFrequency::operator*=(BranchProbability Prob) {
19  Frequency = Prob.scale(Frequency);
20  return *this;
21}
22
23BlockFrequency BlockFrequency::operator*(BranchProbability Prob) const {
24  BlockFrequency Freq(Frequency);
25  Freq *= Prob;
26  return Freq;
27}
28
29BlockFrequency &BlockFrequency::operator/=(BranchProbability Prob) {
30  Frequency = Prob.scaleByInverse(Frequency);
31  return *this;
32}
33
34BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
35  BlockFrequency Freq(Frequency);
36  Freq /= Prob;
37  return Freq;
38}
39
40BlockFrequency &BlockFrequency::operator+=(BlockFrequency Freq) {
41  uint64_t Before = Freq.Frequency;
42  Frequency += Freq.Frequency;
43
44  // If overflow, set frequency to the maximum value.
45  if (Frequency < Before)
46    Frequency = UINT64_MAX;
47
48  return *this;
49}
50
51BlockFrequency BlockFrequency::operator+(BlockFrequency Freq) const {
52  BlockFrequency NewFreq(Frequency);
53  NewFreq += Freq;
54  return NewFreq;
55}
56
57BlockFrequency &BlockFrequency::operator-=(BlockFrequency Freq) {
58  // If underflow, set frequency to 0.
59  if (Frequency <= Freq.Frequency)
60    Frequency = 0;
61  else
62    Frequency -= Freq.Frequency;
63  return *this;
64}
65
66BlockFrequency BlockFrequency::operator-(BlockFrequency Freq) const {
67  BlockFrequency NewFreq(Frequency);
68  NewFreq -= Freq;
69  return NewFreq;
70}
71
72BlockFrequency &BlockFrequency::operator>>=(const unsigned count) {
73  // Frequency can never be 0 by design.
74  assert(Frequency != 0);
75
76  // Shift right by count.
77  Frequency >>= count;
78
79  // Saturate to 1 if we are 0.
80  Frequency |= Frequency == 0;
81  return *this;
82}
83