X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FBlockFrequency.cpp;h=e7f3e1764c52d3a6131f022b081227b2f0887f06;hb=b6cb6238b9c5243ec813a860ae153adda1acddff;hp=dbd790cec3a869ec2df3cc936660f4af31133e84;hpb=385beeb70692988689a0425102900b054743245c;p=oota-llvm.git

diff --git a/lib/Support/BlockFrequency.cpp b/lib/Support/BlockFrequency.cpp
index dbd790cec3a..e7f3e1764c5 100644
--- a/lib/Support/BlockFrequency.cpp
+++ b/lib/Support/BlockFrequency.cpp
@@ -22,8 +22,7 @@ BlockFrequency &BlockFrequency::operator*=(BranchProbability Prob) {
   return *this;
 }
 
-const BlockFrequency
-BlockFrequency::operator*(BranchProbability Prob) const {
+BlockFrequency BlockFrequency::operator*(BranchProbability Prob) const {
   BlockFrequency Freq(Frequency);
   Freq *= Prob;
   return Freq;
@@ -40,7 +39,7 @@ BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
   return Freq;
 }
 
-BlockFrequency &BlockFrequency::operator+=(const BlockFrequency &Freq) {
+BlockFrequency &BlockFrequency::operator+=(BlockFrequency Freq) {
   uint64_t Before = Freq.Frequency;
   Frequency += Freq.Frequency;
 
@@ -51,11 +50,25 @@ BlockFrequency &BlockFrequency::operator+=(const BlockFrequency &Freq) {
   return *this;
 }
 
-const BlockFrequency
-BlockFrequency::operator+(const BlockFrequency &Prob) const {
-  BlockFrequency Freq(Frequency);
-  Freq += Prob;
-  return Freq;
+BlockFrequency BlockFrequency::operator+(BlockFrequency Freq) const {
+  BlockFrequency NewFreq(Frequency);
+  NewFreq += Freq;
+  return NewFreq;
+}
+
+BlockFrequency &BlockFrequency::operator-=(BlockFrequency Freq) {
+  // If underflow, set frequency to 0.
+  if (Frequency <= Freq.Frequency)
+    Frequency = 0;
+  else
+    Frequency -= Freq.Frequency;
+  return *this;
+}
+
+BlockFrequency BlockFrequency::operator-(BlockFrequency Freq) const {
+  BlockFrequency NewFreq(Frequency);
+  NewFreq -= Freq;
+  return NewFreq;
 }
 
 BlockFrequency &BlockFrequency::operator>>=(const unsigned count) {