https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125874
Drea Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2026-06-18
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Component|middle-end |tree-optimization
--- Comment #5 from Drea Pinski <pinskia at gcc dot gnu.org> ---
So in this case the setjmp buffer already went out of scope before the
musttail.
GCC takes the easy way out when dealing with setjmp/returns_twice and does not
figure out the handling here.
But maybe for musttail we don't need to reject returns_twice functions right
away.
```
/* Any function that calls setjmp might have longjmp called from
any called function. ??? We really should represent this
properly in the CFG so that this needn't be special cased. */
if (cfun->calls_setjmp)
{
maybe_error_musttail (call, _("caller uses setjmp"), diag_musttail);
return false;
}
```
We could just reject a taill call for non-musttail call if cfun->calls_setjmp
is set when it comes later on.
This might be an easy thing to implement.
