[Bug c/92086] Provide way to avoid saving callee-saved registers in functions without callers

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92086

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-10-14
                 CC|                            |segher at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Does it need a new attribute at all?

If not, an optimisation like this is obviously beneficial: it saves code
space, after all.  (Well, assuming it doesn't hurt the debug experience).