[Lazarus] UTF8LengthFast returning incorrect results on AARCH64 (MacOS)

[Bart]

On Tue, Dec 28, 2021 at 3:39 PM Marco van de Voort via lazarus
<lazarus at lists.lazarus-ide.org> wrote:

> On what machine did you test? The settings if for the generated code,
> but the actual processor determines the effective speed.

I have a Intel i5 7th generation on my Win10-64 laptop from approx.
2017 (so, it's really old for more modern folks than me).

Compiled for 32-bit:
With -CpCOREI
Unsigned version with multiplication: 1359
Unsigned version with PopCnt        : 1282

Compiled for 32-bit:
With -CpCOREAVX2
Unsigned version with multiplication: 1312
Unsigned version with PopCnt        : 1297

Compiled for 32-bit
No -Cp switch
Unsigned version with multiplication: 1329
Unsigned version with PopCnt        : 3546

B.t.w. what happens if I compile for e.g. CoreAVX2 but my processor
does not support that instructionset.
Will the compilation/build fail, or will the executable just error out?

-- 
Bart