an_extern_func 6 apps/c_backend/pipeline_generator.cpp HalideExtern_2(int, an_extern_func, int, int); an_extern_func 17 apps/c_backend/pipeline_generator.cpp g(x, y) = cast<uint16_t>(f(y, x) + f(x, y) + an_extern_func(x, y) + h());