Optimisation possibilities: current, future and enhancements

[ag0aep6g via Digitalmars-d]

On 08/25/2016 08:15 PM, Basile B. wrote:
> Here's a better code to illustrate the idea:
>
> °°°°°°°°°°°°°°°°°°°°°°
> interface Foo
> {
>     int foo() const;
> }
>
> int use(const(Foo) foo)
> {
>     return foo.foo() + foo.foo();
> }
> °°°°°°°°°°°°°°°°°°°°°°
>
>
> And I'd expect this asm for a 'const optimization' in use():
>
> push rbp
> push rbx
> push rax
> mov rbx, rdi
> mov rax, qword ptr [rbx]
> call qword ptr [rax+08h]
> add eax, eax // const funct = no side effect, so add the 1st result =
> save a CALL
> add rsp, 08h
> pop rbx
> pop rbp
> ret

At least, foo needs to be `pure` for that.