Old problem with performance

[Kagamin]

Weed Wrote:

> The code on C++ is also approximately in 6 times faster a code with
> classes on D. (I do not give an example on C++ because classes on C++
> work just as structures in D.)

> class C {
>     int i;
>     real[5] unused; // to prevent returning this object in registers
> 
>     C opAdd( C src ) {
>         auto ret = new C;
>         ret.i = i + src.i;
>         return ret;
>     }
> }

Well, D class code here is not equivalent to C++ class code. D code has more features, namely, it's polymorphic: C.opAdd is able to work with classes, derived from C, while corresponding C++ code is unable to do so. If you can't use polymorphism, why do you use classes?