title: Ensure that register is pushed to the stack at function entry
body: <p>Typically, a C function is translated by clang for an ARM architecture in a way such that the LR register is pushed on the stack. However, if the function does not contain any function calls itself, LR is not pushed, i.e. the compiler assumes that LR won't be modified.</p>
  
  <p>Is there a way to make the clang/llc always push LR at the beginning of a function, regardless of whether it calls a function or not?</p>