calling convention optimisation & const/immutable ref

[Stefan Koch via Digitalmars-d]

On Monday, 7 November 2016 at 23:19:18 UTC, John Colvin wrote:
> On Monday, 7 November 2016 at 22:46:57 UTC, Stefan Koch wrote:
>> 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 ?
>
> Yeah, I guess it's not a traditional optimisation. I'm 
> suggesting a change to the D ABI to let it use some of the 
> extra information that D has in function signatures.

This is not a good idea.
Also changing to references is not always a performance win,
It introduces another point where caches can stall.