1 struct __attribute__((__packed__)) s { char c; unsigned long long x; }; foo(struct s * s)2 void __attribute__((__noinline__)) foo (struct s *s) { s->x = 0; } main(void)3 int main (void) { struct s s = { 1, ~0ULL }; foo (&s); return s.x != 0; } 4