Strange counter-performance in an alternative `decimalLength9` function

[Basile B.]

On Thursday, 27 February 2020 at 14:12:35 UTC, Basile B. wrote:
> On Wednesday, 26 February 2020 at 22:07:30 UTC, Johan wrote:
>> On Wednesday, 26 February 2020 at 00:50:35 UTC, Basile B. 
>> wrote:
>>> [...]
>>
>> Hi Basile,
>>   I recently saw this presentation: 
>> https://www.youtube.com/watch?v=Czr5dBfs72U
>
> Andrei made a talk about this too a few years ago.
>
>> It has some ideas that may help you make sure your 
>> measurements are good and may give you ideas to find the 
>> performance bottleneck or where to optimize.
>> llvm-mca is featured on godbolt.org: 
>> https://mca.godbolt.org/z/YWp3yv
>>
>> cheers,
>>   Johan

https://www.youtube.com/watch?v=Qq_WaiwzOtI