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 const BlockFrequency
  26 BlockFrequency::operator*(BranchProbability Prob) const {
  27   BlockFrequency Freq(Frequency);
  28   Freq *= Prob;
  29   return Freq;
  30 }
  31
  32 BlockFrequency &BlockFrequency::operator/=(BranchProbability Prob) {
  33   Frequency = Prob.scaleByInverse(Frequency);
  34   return *this;
  35 }
  36
  37 BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
  38   BlockFrequency Freq(Frequency);
  39   Freq /= Prob;
  40   return Freq;
  41 }
  42
  43 BlockFrequency &BlockFrequency::operator+=(const BlockFrequency &Freq) {
  44   uint64_t Before = Freq.Frequency;
  45   Frequency += Freq.Frequency;
  46
  47   // If overflow, set frequency to the maximum value.
  48   if (Frequency < Before)
  49     Frequency = UINT64_MAX;
  50
  51   return *this;
  52 }
  53
  54 const BlockFrequency
  55 BlockFrequency::operator+(const BlockFrequency &Prob) const {
  56   BlockFrequency Freq(Frequency);
  57   Freq += Prob;
  58   return Freq;
  59 }
  60
  61 BlockFrequency &BlockFrequency::operator>>=(const unsigned count) {
  62   // Frequency can never be 0 by design.
  63   assert(Frequency != 0);
  64
  65   // Shift right by count.
  66   Frequency >>= count;
  67
  68   // Saturate to 1 if we are 0.
  69   Frequency |= Frequency == 0;
  70   return *this;
  71 }