https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81622
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I take back the ARRAY_TYPE thing, apparently it is different for C vs. C++, in C one always sees there POINTER_TYPE, while in C++ always ARRAY_TYPE. Anyway, your patch seems to be wrong, POINTER_TYPE_P's argument should be a type, while you are passing it an argument instead ((*arglist)[1] is arg1, not arg1_type = TREE_TYPE (arg1)).
