Add getBlockProfileCount method to BlockFrequencyInfo

Differential Revision: http://reviews.llvm.org/D18233

llvm-svn: 264179

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
index 90b7a339a0f..8b19b2e19c4 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
@@ -129,6 +129,20 @@ BlockFrequency BlockFrequencyInfo::getBlockFreq(const BasicBlock *BB) const {
   return BFI ? BFI->getBlockFreq(BB) : 0;
 }
 
+Optional<uint64_t>
+BlockFrequencyInfo::getBlockProfileCount(const BasicBlock *BB) const {
+  auto EntryCount = getFunction()->getEntryCount();
+  if (!EntryCount)
+    return None;
+  // Use 128 bit APInt to do the arithmetic to avoid overflow.
+  APInt BlockCount(128, EntryCount.getValue());
+  APInt BlockFreq(128, getBlockFreq(BB).getFrequency());
+  APInt EntryFreq(128, getEntryFreq());
+  BlockCount *= BlockFreq;
+  BlockCount = BlockCount.udiv(EntryFreq);
+  return BlockCount.getLimitedValue();
+}
+
 void BlockFrequencyInfo::setBlockFreq(const BasicBlock *BB,
                                       uint64_t Freq) {
   assert(BFI && "Expected analysis to be available");