https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107014
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- The whole point of "flatten" is that there's _no_ limit. Looking at the function I don't see why you'd ever use that? If the desire is to force inlining a specific call then I think there's currently no good way to get that. It doesn't seem to be possible to use an always-inline alias to get this behavior at least. Some not existing #pragma GCC inline might be a better solution than "flatten". But as said, I'd just remove "flatten" - is it known what it was added for?