Index: lib/CodeGen/MachineSink.cpp
===================================================================
--- lib/CodeGen/MachineSink.cpp
+++ lib/CodeGen/MachineSink.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/MachinePostDominators.h"
@@ -53,6 +54,7 @@
     MachineDominatorTree *DT;      // Machine dominator tree
     MachinePostDominatorTree *PDT; // Machine post dominator tree
     MachineLoopInfo *LI;
+    const MachineBlockFrequencyInfo *MBFI;
     AliasAnalysis *AA;
 
     // Remember which edges have been considered for breaking.
@@ -81,6 +83,7 @@
       AU.addPreserved<MachineDominatorTree>();
       AU.addPreserved<MachinePostDominatorTree>();
       AU.addPreserved<MachineLoopInfo>();
+      AU.addRequired<MachineBlockFrequencyInfo>();
     }
 
     void releaseMemory() override {
@@ -247,6 +250,7 @@
   DT = &getAnalysis<MachineDominatorTree>();
   PDT = &getAnalysis<MachinePostDominatorTree>();
   LI = &getAnalysis<MachineLoopInfo>();
+  MBFI = &getAnalysis<MachineBlockFrequencyInfo>();
   AA = &getAnalysis<AliasAnalysis>();
 
   bool EverMadeChange = false;
@@ -566,14 +570,19 @@
       }
 
       // Otherwise, we should look at all the successors and decide which one
-      // we should sink to.
-      // We give successors with smaller loop depth higher priority.
+      // we should sink to. If we have reliable block frequency information
+      // (frequency != 0) available, give successors with smaller frequencies
+      // higher priority, otherwise prioritize smaller loop depths.
       SmallVector<MachineBasicBlock*, 4> Succs(MBB->succ_begin(), MBB->succ_end());
-      // Sort Successors according to their loop depth.
+      // Sort Successors according to their loop depth or block frequency info.
       std::stable_sort(
           Succs.begin(), Succs.end(),
           [this](const MachineBasicBlock *LHS, const MachineBasicBlock *RHS) {
-            return LI->getLoopDepth(LHS) < LI->getLoopDepth(RHS);
+            uint64_t LHSFreq = MBFI->getBlockFreq(LHS).getFrequency();
+            uint64_t RHSFreq = MBFI->getBlockFreq(RHS).getFrequency();
+            bool UseBlockFreq = LHSFreq != 0 && RHSFreq != 0;
+            return UseBlockFreq ? LHSFreq < RHSFreq :
+              LI->getLoopDepth(LHS) < LI->getLoopDepth(RHS);
           });
       for (SmallVectorImpl<MachineBasicBlock *>::iterator SI = Succs.begin(),
              E = Succs.end(); SI != E; ++SI) {