Paul Eggert <eggert@cs.ucla.edu> writes:

> Alex Gramiak wrote:
>> Though I don't think that these macros, used sparingly around code such
>> as emacs_abort, would make it harder to read/write/maintain.
>
> These macro calls would not help near calls to emacs_abort, as it should already
> be obvious to a careful human reader that the jump to emacs_abort is the road
> less traveled. (That's also obvious to GCC, since emacs_abort is _Noreturn.)

To human readers, yes, but from what I can tell, GCC is mixed on this.
When applying the following diff that surrounds emacs_abort in
bytecode.c and xdisp.c, the assembly in both applied/unapplied is the
same for bytecode.c, but not for xdisp.c (even without the LIKELY
cases). I tested using gcc -O2 -S.

Also, I tried putting a LIKELY in lisp_h_CHECK_TYPE (seems like a nice
place for one) and that yielded different assembly for fns.c, even
though wrong_type_argument is _Noreturn.