Slow performance compared to C++, ideas?

[deadalnix]

On Thursday, 6 June 2013 at 07:43:30 UTC, Paulo Pinto wrote:
> As I mentioned before, given that I speak more than really 
> using D for anything, my opinion should not count.
>
> In C#'s case, which is similar to D, you not only have a VM, 
> but also ahead of time compilation.
>
> Virtual by default wins when you have a VM that can do 
> devirtualization.
>

devirtualization is a link time problem, not a runtime one. We 
can do that in D (except when it come to shared objects) and I 
even proposed solutions to do so.

revirtualization, however, can only be done with a JIT compiler. 
And it is done in C# . They had this option, D won't have it.

> When doing static compilation, even with LTO, you are limited 
> in what you can do, specially if generating dynamic libraries.
>

Exact, but this is nothing specific to virtual. shared library 
come at a cost, as the call is opaque to the compiler. It has to 
assume the worse and must disable most optimizations anyway. You 
are trying to pose a bandage on a wooden leg.