https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112296
--- Comment #9 from Richard Henderson <rth at gcc dot gnu.org> ---
> Thanks. So yes,
>
> macro(x++);
>
> incrementing x twice would have been odd - but that's the usual bug
> in this kind of macro definition. Fixing it by throwing away
> side-effects (and always going the out_of_line_function (x) path!)
> for the __builtin_constant_p argument is an odd choice.
In the beginning __builtin_constant_p was resolved immediately,
so formulating this as
#define macro(x) \
({ __typeof(x) _x = (x); \
__builtin_constant_p(_x) })
would always return false, defeating the purpose.
> The execute.exp testcase suggests the intention but the testcases
> verification is somewhat incomplete (it lacks verifying the side-effects
> are gone).
That's probably my omission. ;-)
