Index: llvm/include/llvm/CodeGen/MBFIWrapper.h
===================================================================
--- llvm/include/llvm/CodeGen/MBFIWrapper.h
+++ llvm/include/llvm/CodeGen/MBFIWrapper.h
@@ -28,6 +28,8 @@
 
   BlockFrequency getBlockFreq(const MachineBasicBlock *MBB) const;
   void setBlockFreq(const MachineBasicBlock *MBB, BlockFrequency F);
+  Optional<uint64_t> getBlockProfileCount(const MachineBasicBlock *MBB) const;
+
   raw_ostream &printBlockFreq(raw_ostream &OS,
                               const MachineBasicBlock *MBB) const;
   raw_ostream &printBlockFreq(raw_ostream &OS,
Index: llvm/lib/CodeGen/MBFIWrapper.cpp
===================================================================
--- llvm/lib/CodeGen/MBFIWrapper.cpp
+++ llvm/lib/CodeGen/MBFIWrapper.cpp
@@ -30,6 +30,18 @@
   MergedBBFreq[MBB] = F;
 }
 
+Optional<uint64_t>
+MBFIWrapper::getBlockProfileCount(const MachineBasicBlock *MBB) const {
+  auto I = MergedBBFreq.find(MBB);
+
+  // Modified block frequency also impacts profile count. So we should compute
+  // profile count from new block frequency if it has been changed.
+  if (I != MergedBBFreq.end())
+    return MBFI.getProfileCountFromFreq(I->second.getFrequency());
+
+  return MBFI.getBlockProfileCount(MBB);
+}
+
 raw_ostream & MBFIWrapper::printBlockFreq(raw_ostream &OS,
                                           const MachineBasicBlock *MBB) const {
   return MBFI.printBlockFreq(OS, getBlockFreq(MBB));
Index: llvm/lib/CodeGen/MachineBlockPlacement.cpp
===================================================================
--- llvm/lib/CodeGen/MachineBlockPlacement.cpp
+++ llvm/lib/CodeGen/MachineBlockPlacement.cpp
@@ -418,7 +418,7 @@
   /// The return value is used to model tail duplication cost.
   BlockFrequency getBlockCountOrFrequency(const MachineBasicBlock *BB) {
     if (UseProfileCount) {
-      auto Count = MBFI->getMBFI().getBlockProfileCount(BB);
+      auto Count = MBFI->getBlockProfileCount(BB);
       if (Count)
         return *Count;
       else