Re: define pg_structiszero(addr, s, r)

Hi,

On Thu, Nov 14, 2024 at 08:22:23AM -0300, Ranier Vilela wrote:
> Em qui., 14 de nov. de 2024 ąs 07:09, Bertrand Drouvot <
> bertranddrouvot.pg@gmail.com> escreveu:
>
> > Hi,
> >
> > On Thu, Nov 14, 2024 at 09:27:06AM +0900, Michael Paquier wrote:
> > > Makes sense to me to just do that, with a first < 8 loop, and a second
> > > for the 8~63 range.
> >
> > Thanks for looking at it!
> >
> > > There is also a "cant'" in the last size_t check.  Simple typo.
> >
> > Please find attached v12, with more comments and comments changes to
> > explain
> > the multiple cases (for safety) and phases (for efficiency).
> >
> Is it worth mentioning that pg_memory_is_all_zeros does not work correctly
> on 32-bit systems?
>
> (63 < (size_t) * 8) /* 63 - 32*/

I think that the code is fully portable on 32-bit systems as it's using size_t
in all the places.

Maybe I'm doing something wrong.
But I'm testing in 32-bit, with the size set to 63, with v12 and I'm seeing the SIMD loop execute.
Because the test

if (len < sizeof(size_t) * 8) // 8-63 bytes
failed.

I expected that with size 63, it would be solved by case 2, or am I wrong?