https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97943
--- Comment #6 from Jason Merrill <jason at gcc dot gnu.org> --- I think we should reject trying to clear the padding of a flexible/zero-length array, with error rather than sorry. And handle an array at the end of a struct like any other array. Nobody should be using this builtin with the struct hack, it's impossible for it to do anything sensible.
