lib/Support/BlockFrequency.cpp

   1 //====--------------- lib/Support/BlockFrequency.cpp -----------*- 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 #include "llvm/Support/BlockFrequency.h"
  15 #include "llvm/Support/raw_ostream.h"
  16 #include <cassert>
  17
  18 using namespace llvm;
  19
  20 BlockFrequency &BlockFrequency::operator*=(BranchProbability Prob) {
  21   Frequency = Prob.scale(Frequency);
  22   return *this;
  23 }
  24
  25 BlockFrequency BlockFrequency::operator*(BranchProbability Prob) const {
  26   BlockFrequency Freq(Frequency);
  27   Freq *= Prob;
  28   return Freq;
  29 }
  30
  31 BlockFrequency &BlockFrequency::operator/=(BranchProbability Prob) {
  32   Frequency = Prob.scaleByInverse(Frequency);
  33   return *this;
  34 }
  35
  36 BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
  37   BlockFrequency Freq(Frequency);
  38   Freq /= Prob;
  39   return Freq;
  40 }
  41
  42 BlockFrequency &BlockFrequency::operator+=(BlockFrequency Freq) {
  43   uint64_t Before = Freq.Frequency;
  44   Frequency += Freq.Frequency;
  45
  46   // If overflow, set frequency to the maximum value.
  47   if (Frequency < Before)
  48     Frequency = UINT64_MAX;
  49
  50   return *this;
  51 }
  52
  53 BlockFrequency BlockFrequency::operator+(BlockFrequency Freq) const {
  54   BlockFrequency NewFreq(Frequency);
  55   NewFreq += Freq;
  56   return NewFreq;
  57 }
  58
  59 BlockFrequency &BlockFrequency::operator-=(BlockFrequency Freq) {
  60   // If underflow, set frequency to 0.
  61   if (Frequency <= Freq.Frequency)
  62     Frequency = 0;
  63   else
  64     Frequency -= Freq.Frequency;
  65   return *this;
  66 }
  67
  68 BlockFrequency BlockFrequency::operator-(BlockFrequency Freq) const {
  69   BlockFrequency NewFreq(Frequency);
  70   NewFreq -= Freq;
  71   return NewFreq;
  72 }
  73
  74 BlockFrequency &BlockFrequency::operator>>=(const unsigned count) {
  75   // Frequency can never be 0 by design.
  76   assert(Frequency != 0);
  77
  78   // Shift right by count.
  79   Frequency >>= count;
  80
  81   // Saturate to 1 if we are 0.
  82   Frequency |= Frequency == 0;
  83   return *this;
  84 }