https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109877
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- That is generally the case for the standard C/C++ attributes (arguments just need to be a balanced token sequence), but not for GNU attributes. Although, all standard C/C++ attributes we support right now other than OpenMP ones follow the GNU attribute rules as well.
