RFA: RL78: Save the frame pointer if it is used.

[Nicholas Clifton]

Hi DJ,

>>    OK to apply ?
>
> Ok, but...

Thanks - committed.

>> -  if (regno == FRAME_POINTER_REGNUM && frame_pointer_needed)
>> +  if (regno == FRAME_POINTER_REGNUM
>> +      && (frame_pointer_needed || df_regs_ever_live_p (regno)))
>
> Do we want regs_ever_live or regs_ever_written_to ?  I seem to recall
> changing a port... mep perhaps... to only save registers that are
> changed, not registers that are used but read-only.

You are right, we would only need to save the FP if it is written to, 
but I could not find a regs_ever_written_to, or something similar.  At 
least the current version of the patch will still work though, even if 
there is a needless save/restore of the FP.

Cheers
   Nick