calling convention optimisation & const/immutable ref

[Stefan Koch via Digitalmars-d]

On Monday, 7 November 2016 at 21:45:42 UTC, John Colvin wrote:
> On Monday, 7 November 2016 at 20:23:37 UTC, Jacob Carlborg 
> wrote:
>> Since D is a systems programming language, wouldn't the user 
>> want to have control over this?
>
> It's just another optimisation in a long list of optimisations 
> that can be performed without changing semantics. What about 
> this one is less "systems language" worthy than - for example - 
> constant folding or dead code elimination?

What about ABI compatibility ?