1 files changed, 2 insertions, 0 deletions
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 006a10a0ce..c29a6e339e 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1041,6 +1041,8 @@ bool MachineInstr::addRegisterKilled(unsigned IncomingReg,
         if (MO.isKill())
           // The register is already marked kill.
           return true;
+        // This operand can no longer be undef since Reg is live-in.
+        MO.setIsUndef(false);
         if (isPhysReg && isRegTiedToDefOperand(i))
           // Two-address uses of physregs must not be marked kill.
           return true;