Reset isUndef when removing subreg from a def operand

llvm-svn: 279437

llvm/lib/CodeGen/MachineInstr.cpp

@@ -93,6 +93,8 @@ void MachineOperand::substPhysReg(unsigned Reg, const TargetRegisterInfo &TRI) {
     // Note that getSubReg() may return 0 if the sub-register doesn't exist.
     // That won't happen in legal code.
     setSubReg(0);
+    if (isDef())
+      setIsUndef(false);
   }
   setReg(Reg);
 }