CTFE Status

[Stefan Koch via Digitalmars-d]

On Wednesday, 7 December 2016 at 18:50:20 UTC, Stefan Koch wrote:
> On Wednesday, 7 December 2016 at 18:00:40 UTC, Stefan Koch 
> wrote:
>> I have an update about ctfe performance.
>> I wondered for quite a while why newCTFE had a 5 millisecond 
>> overhead, when compared the old interpreter.
>> Since on my charts it had comparable or better stats.
>> I finally figured it out.
>>
>> Because the interpreter is supposed to be ctfe-able itself it 
>> uses a gc-allocated stack.
>> And that in turn call envokes the gc.
>> The mark phase of the garbage-collector matches up exactly 
>> with the extra time taken.
>>
>> I have no idea, why this happens though since the GC is 
>> supposed to be disabled.
>
> It turns out that almost classes in dmd that are em-placed.
> Whereas by bytecode visitor uses the regular new, because it is 
> fairly sizable. The gc is much more visible.
>
> Although that does still not explain why GC.disable seems to 
> have no effect.

After a few more iterations the observed slow down seems to 
disappear.
I am suspicious.