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

[pinskia at gcc dot gnu.org]

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

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I dont see this helping code in real life programs.  Can you explain where you
think this could be used?