https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126552
--- Comment #1 from Drea Pinski <pinskia at gcc dot gnu.org> --- This happens in the front-end: "rf" 0B For both C and C++ front-ends. For GCC 16+ you should be using hard register constraints instead: https://gcc.gnu.org/onlinedocs/gcc-16.1.0/gcc/Hard-Register-Constraints.html
