diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index 90ca25a6cef3..c35d6e0daef1 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SparseBitVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
@@ -70,6 +71,8 @@ namespace {
     // will be split.
     SetVector<std::pair<MachineBasicBlock*,MachineBasicBlock*> > ToSplit;
 
+    SparseBitVector<> RegsToClearKillFlags;
+
   public:
     static char ID; // Pass identification
     MachineSinking() : MachineFunctionPass(ID) {
@@ -287,6 +290,12 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) {
     if (!MadeChange) break;
     EverMadeChange = true;
   }
+
+  // Now clear any kill flags for recorded registers.
+  for (auto I : RegsToClearKillFlags)
+    MRI->clearKillFlags(I);
+  RegsToClearKillFlags.clear();
+
   return EverMadeChange;
 }
 
@@ -761,7 +770,7 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
   // used registers.
   for (MachineOperand &MO : MI->operands()) {
     if (MO.isReg() && MO.isUse())
-      MRI->clearKillFlags(MO.getReg());
+      RegsToClearKillFlags.set(MO.getReg()); // Remember to clear kill flags.
   }
 
   return true;