3 files changed, 26 insertions, 0 deletions
diff --git a/lib/Analysis/Analysis.cpp b/lib/Analysis/Analysis.cpp
index e57ba78332..71e0a83269 100644
--- a/lib/Analysis/Analysis.cpp
+++ b/lib/Analysis/Analysis.cpp
@@ -23,6 +23,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeAliasSetPrinterPass(Registry);
   initializeNoAAPass(Registry);
   initializeBasicAliasAnalysisPass(Registry);
+  initializeBlockFrequencyPass(Registry);
   initializeBranchProbabilityInfoPass(Registry);
   initializeCFGViewerPass(Registry);
   initializeCFGPrinterPass(Registry);
diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp
index 15059c733a..263ea2c26b 100644
--- a/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/lib/Analysis/BranchProbabilityInfo.cpp
@@ -279,6 +279,21 @@ uint32_t BranchProbabilityInfo::getSumForBlock(BasicBlock *BB) const {
   return Sum;
 }
 
+uint32_t BranchProbabilityInfo::getBackSumForBlock(BasicBlock *BB) const {
+  uint32_t Sum = 0;
+
+  for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I) {
+    BasicBlock *Pred = *I;
+    uint32_t Weight = getEdgeWeight(Pred, BB);
+    uint32_t PrevSum = Sum;
+
+    Sum += Weight;
+    assert(Sum > PrevSum); (void) PrevSum;
+  }
+
+  return Sum;
+}
+
 bool BranchProbabilityInfo::isEdgeHot(BasicBlock *Src, BasicBlock *Dst) const {
   // Hot probability is at least 4/5 = 80%
   uint32_t Weight = getEdgeWeight(Src, Dst);
@@ -345,6 +360,15 @@ getEdgeProbability(BasicBlock *Src, BasicBlock *Dst) const {
   return BranchProbability(N, D);
 }
 
+BranchProbability BranchProbabilityInfo::
+getBackEdgeProbability(BasicBlock *Src, BasicBlock *Dst) const {
+
+  uint32_t N = getEdgeWeight(Src, Dst);
+  uint32_t D = getBackSumForBlock(Dst);
+
+  return BranchProbability(N, D);
+}
+
 raw_ostream &
 BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS, BasicBlock *Src,
                                             BasicBlock *Dst) const {
diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt
index 1a975bf4a5..ab846a26b4 100644
--- a/lib/Analysis/CMakeLists.txt
+++ b/lib/Analysis/CMakeLists.txt
@@ -6,6 +6,7 @@ add_llvm_library(LLVMAnalysis
   AliasSetTracker.cpp
   Analysis.cpp
   BasicAliasAnalysis.cpp
+  BlockFrequency.cpp
   BranchProbabilityInfo.cpp
   CFGPrinter.cpp
   CaptureTracking.cpp