[fpc-devel] Attn: J. Gareth // 3.3.1 opt = slower // Fwd: [Lazarus] Faster than popcnt

[J. Gareth Moreton]

Interesting - thank you.  Will be interesting to study the assembler 
output to see what's going on.

I'm honoured that I've become the go-to person when optimisation is 
concerned!

Gareth aka. Kit

On 03/01/2022 11:54, Martin Frb via fpc-devel wrote:
> Hi Gareth,
>
> not sure if this is of interest to you, but I see you do a lot on the 
> optimizer....
>
> While testing the attached, I found that one of the functions was 
> notable slower when compiled with 3.3.1 (compared to 3.2.3).
> So maybe something you are interested in looking at?
>
> The Code in "Utf8LengthFash" (fst) went from around 600ms to 700ms.
>
> 3.3.1 from Dec 10th
> 3.2.3 from Dec 9th
>
> Core I7 8700K
> -O4 -Cpcoreavx2
>
> fpc 3.2.3 /   fpc 3.3.1
>
> fst 594       fst 688
> fst 578       fst 703
> fst 578       fst 687
> fst 562       fst 688
>
> pop 485       pop 485
> pop 500       pop 500
> pop 500       pop 484
> pop 484       pop 500
>
> add 594       add 422
> add 578       add 438
> add 578       add 437
> add 594       add 453
>
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