Doubts about the performance of array concatenation

[ddcovery]

On Tuesday, 1 December 2020 at 23:43:31 UTC, Max Haughton wrote:
> On Tuesday, 1 December 2020 at 22:49:55 UTC, ddcovery wrote:
>> Yesterday I really shocked when, comparing one algorithm 
>> written in javascript and the equivalent in D, javascript 
>> performed better!!!
>>
>> [...]
>
> Use ldc, rdmd can invoke it for you. DMD's optimizer is not 
> even close to as advanced as a modern JavaScript engine's - 
> that's why we use it for fast build times instead of 
> performance.

Impressive performance increase:

$ ldc2 -O -release  --run sorted.d
# D
1.0M: 810 ms
1.5M: 1324 ms
3.0M: 2783 ms
6.0M: 5727 ms

Thanks Max