Dude about ~ array concatenation performance

[ddcovery]

On Wednesday, 2 December 2020 at 06:31:49 UTC, H. S. Teoh wrote:
> On Tue, Dec 01, 2020 at 10:49:55PM +0000, ddcovery via 
> Digitalmars-d-learn wrote:
>> Yesterday I really shocked when, comparing one algorithm 
>> written in javascript and the equivalent in D, javascript 
>> performed better!!!
> [...]
>> With 1 million Double numbers (generated randomly):
>>   Javascript (node 12): 1507 ms
>>   DMD: 2166 ms
>> 
>> With 6 million Double numbers
>>   Javascript (node 12): 10776 ms
>>   DMD: 15243 ms
>
> Yeah, when it comes to performance-related things, don't bother 
> with DMD.  Its optimizer is known to have limitations, and IME 
> consistently produces code that underperforms LDC-generated 
> code by about 20-30%, sometimes even as high as 40%.
>
> For performance comparisons, always use GDC/LDC.
>
>
> T

After applying adecuate parametrization (thanks to Max Haughton 
for the tips), LDC generated code is running almost 3 times 
faster than DMD one!!!