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