Index: machinelicm_clangformat_modv1.cpp
===================================================================
--- machinelicm_clangformat_modv1.cpp
+++ machinelicm_clangformat_modv1.cpp
@@ -23,6 +23,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
@@ -75,6 +76,25 @@
                  cl::desc("Hoist invariant stores"),
                  cl::init(true), cl::Hidden);
 
+static cl::opt<unsigned>
+BlockFrequencyRatioThreshold("block-freq-ratio-threshold",
+		             cl::desc("Block frequency ratio threshold to "
+			              "disable instruction hoisting"),
+		             cl::init(100), cl::Hidden);
+
+enum NotHoistDueToBlockHotnessType { Disable, Enable_PGO, Enable };
+
+static cl::opt<NotHoistDueToBlockHotnessType>
+NotHoistDueToBlockHotness("not-hoist-due-to-block-hotness",
+                cl::desc("Disable instruction hoist due to block hotness"),
+                cl::init(Disable), cl::Hidden,
+                cl::values(clEnumValN(Disable, "disable",
+			   "disable the feature"),
+                           clEnumValN(Enable_PGO, "enable-pgo",
+			   "enable the feature when using profile data"),
+                           clEnumValN(Enable, "enable",
+			   "enable the feature with/without profile data")));
+
 STATISTIC(NumHoisted,
           "Number of machine instructions hoisted out of loops");
 STATISTIC(NumLowRP,
@@ -87,6 +107,8 @@
           "Number of machine instructions hoisted out of loops post regalloc");
 STATISTIC(NumStoreConst,
           "Number of stores of const phys reg hoisted out of loops");
+STATISTIC(NumNotHoistedDueToHotness,
+	  "Number of instructions not hoisted due to block frequency hotness");
 
 namespace {
 
@@ -101,6 +123,7 @@
 
     // Various analyses that we use...
     AliasAnalysis        *AA;      // Alias analysis info.
+    MachineBlockFrequencyInfo *MBFI; // Machine block frequncy info
     MachineLoopInfo      *MLI;     // Current MachineLoopInfo
     MachineDominatorTree *DT;      // Machine dominator tree for the cur loop
 
@@ -150,6 +173,8 @@
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.addRequired<MachineLoopInfo>();
+      if (NotHoistDueToBlockHotness != Disable)
+        AU.addRequired<MachineBlockFrequencyInfo>();
       AU.addRequired<MachineDominatorTree>();
       AU.addRequired<AAResultsWrapperPass>();
       AU.addPreserved<MachineLoopInfo>();
@@ -246,6 +271,9 @@
 
     void InitCSEMap(MachineBasicBlock *BB);
 
+    bool IsHoistingFromColdToHotBlock(MachineBasicBlock *CurBB,
+                                      MachineBasicBlock *Preheader);
+
     MachineBasicBlock *getCurPreheader();
   };
 
@@ -276,6 +304,7 @@
 INITIALIZE_PASS_BEGIN(MachineLICM, DEBUG_TYPE,
                       "Machine Loop Invariant Code Motion", false, false)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineBlockFrequencyInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
 INITIALIZE_PASS_END(MachineLICM, DEBUG_TYPE,
@@ -284,6 +313,7 @@
 INITIALIZE_PASS_BEGIN(EarlyMachineLICM, "early-machinelicm",
                       "Early Machine Loop Invariant Code Motion", false, false)
 INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineBlockFrequencyInfo)
 INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
 INITIALIZE_PASS_END(EarlyMachineLICM, "early-machinelicm",
@@ -334,6 +364,8 @@
   }
 
   // Get our Loop information...
+  if (NotHoistDueToBlockHotness != Disable)
+    MBFI = &getAnalysis<MachineBlockFrequencyInfo>();
   MLI = &getAnalysis<MachineLoopInfo>();
   DT  = &getAnalysis<MachineDominatorTree>();
   AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
@@ -1434,6 +1466,15 @@
 /// that are safe to hoist, this instruction is called to do the dirty work.
 /// It returns true if the instruction is hoisted.
 bool MachineLICMBase::Hoist(MachineInstr *MI, MachineBasicBlock *Preheader) {
+  MachineBasicBlock *CurBB = MI->getParent();
+  bool hasProfileData = CurBB->getParent()->getFunction().hasProfileData();
+
+  // Disable the instruction hoisting due to block hotness
+  if ((NotHoistDueToBlockHotness == Enable ||
+      (NotHoistDueToBlockHotness == Enable_PGO && hasProfileData)) &&
+      IsHoistingFromColdToHotBlock(CurBB, Preheader))
+    return false;
+
   // First check whether we should hoist this instruction.
   if (!IsLoopInvariantInst(*MI) || !IsProfitableToHoist(*MI)) {
     // If not, try unfolding a hoistable load.
@@ -1528,3 +1569,23 @@
   return CurPreheader;
 }
 
+bool MachineLICMBase::IsHoistingFromColdToHotBlock(MachineBasicBlock *CurBB,
+    MachineBasicBlock *Preheader) {
+  // Parse source and target basic block frequency from MBFI
+  uint64_t SrcBF = MBFI->getBlockFreq(CurBB).getFrequency();
+  uint64_t DstBF = MBFI->getBlockFreq(Preheader).getFrequency();
+
+  // Disable the hoisting if source block frequency is zero
+  if (!SrcBF)
+    return true;
+
+  double Ratio = (double)DstBF / SrcBF;
+  // Compare the block frequency ratio with the threshold
+  if (Ratio > BlockFrequencyRatioThreshold) {
+    ++NumNotHoistedDueToHotness;
+    return true;
+  }
+
+  return false;
+}
+