Doubts about the performance of array concatenation

[Max Haughton]

On Wednesday, 2 December 2020 at 00:08:55 UTC, ddcovery wrote:
> 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

I've written a github issue on your repository with flags to get 
the most out of LLVM.