f(void)1 void f (void) 2 { 3 } 4 __attribute__((__optimize__("O2"))) g(void f ())5 void g (void f()) 6 { 7 f(); 8 } 9 __attribute__((__optimize__("O2"))) h(void)10 void h (void) 11 { 12 g(f); 13 } 14