Performance improvements for D / DMD compiler.

[Christian Kamm]

> What's on your wish-list (let's leave the GC and other library  
> functionality out of this for now <g>)?

I'd like to see unneccessary copies being optimized away, especially of  
large structs passed to functions. The workaround

// use inout to pass s by reference, it is not actually modified
void foo(inout LargeStruct s)

is just abusing inout. In my opinion it should be an in parameter and D  
should detect whether a copy is neccessary or not.

It's not done already, is it?

Christian