Why is D significantly slower than C# in this instance?

[Artjom]

On Tuesday, 11 April 2023 at 01:50:58 UTC, Steven Schveighoffer 
wrote:
> On 4/10/23 9:49 PM, Steven Schveighoffer wrote:
>> Lining up pseudocode so you can see:
>> 
>
> oof, forgot the formatting ticks:
>
> ```
> D:  foreach(i; 0 .. len) foreach(j; 0 .. len)
> C#: foreach(i; 0 .. len) foreach(j; i .. len)
> ```
>
> -Steve

silly me, I'll fix that and try compile with ldc, see whatll 
happen