https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117308
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- I don't think there is any particular limit, it's only limited by your available RAM when compiling. You will probably experience unacceptably slow compile times long before you reach a physical limit, but at some point GCC will just fail to allocate any more memory and either be killed by the OOM Killer or abort due to a failed allocation.
