diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index ea4da9d7332..8821bef7461 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7988,9 +7988,15 @@ X86TargetLowering::EmitAtomicBit6432WithCustomInserter(MachineInstr *bInstr,
   MachineOperand& dest1Oper = bInstr->getOperand(0);
   MachineOperand& dest2Oper = bInstr->getOperand(1);
   MachineOperand* argOpers[2 + X86AddrNumOperands];
-  for (int i=0; i < 2 + X86AddrNumOperands; ++i)
+  for (int i=0; i < 2 + X86AddrNumOperands; ++i) {
     argOpers[i] = &bInstr->getOperand(i+2);
 
+    // We use some of the operands multiple times, so conservatively just
+    // clear any kill flags that might be present.
+    if (argOpers[i]->isReg() && argOpers[i]->isUse())
+      argOpers[i]->setIsKill(false);
+  }
+
   // x86 address has 5 operands: base, index, scale, displacement, and segment.
   int lastAddrIndx = X86AddrNumOperands - 1; // [0,3]