lib/Support/BlockFrequency.cpp

   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
  16 using namespace llvm;
  17
  18 BlockFrequency &BlockFrequency::operator*=(BranchProbability Prob) {
  19   Frequency = Prob.scale(Frequency);
  20   return *this;
  21 }
  22
  23 BlockFrequency BlockFrequency::operator*(BranchProbability Prob) const {
  24   BlockFrequency Freq(Frequency);
  25   Freq *= Prob;
  26   return Freq;
  27 }
  28
  29 BlockFrequency &BlockFrequency::operator/=(BranchProbability Prob) {
  30   Frequency = Prob.scaleByInverse(Frequency);
  31   return *this;
  32 }
  33
  34 BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
  35   BlockFrequency Freq(Frequency);
  36   Freq /= Prob;
  37   return Freq;
  38 }
  39
  40 BlockFrequency &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
  51 BlockFrequency BlockFrequency::operator+(BlockFrequency Freq) const {
  52   BlockFrequency NewFreq(Frequency);
  53   NewFreq += Freq;
  54   return NewFreq;
  55 }
  56
  57 BlockFrequency &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
  66 BlockFrequency BlockFrequency::operator-(BlockFrequency Freq) const {
  67   BlockFrequency NewFreq(Frequency);
  68   NewFreq -= Freq;
  69   return NewFreq;
  70 }
  71
  72 BlockFrequency &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 }