Strange counter-performance in an alternative `decimalLength9` function

[Bruce Carneal]

On Wednesday, 26 February 2020 at 19:44:05 UTC, Bruce Carneal 
wrote:
> On Wednesday, 26 February 2020 at 13:50:11 UTC, Basile B. wrote:
>> On Wednesday, 26 February 2020 at 00:50:35 UTC, Basile B. 
>> wrote:
>> ...
>>     foreach (i; 0 .. count)
>>         sum += funcs[func](i);
>
> The input stream is highly predictable and strongly skewed 
> towards higher digits.
>
> The winning function implementation lines up with that 
> distribution.  It would not fare as well with higher entropy 
> input.

Using sorted equi-probable inputs (N 1 digit numbers, N 2 digit 
numbers, ...) decimalLength9_0 beats a simple branchless 
implementation by about 10%.

After shuffling the input, branchless wins by 2.4X (240%).