Re: ARM SVE issues with non "standard" vector lengths

[Laurent Desnogues <laurent.desnogues@gmail.com>]

On Thu, Apr 23, 2020 at 5:19 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 4/23/20 6:59 AM, Laurent Desnogues wrote:
> > 2. sve_zip_p
> >
> > This generates extraneous data in the higher part of the result.
> >
> > I hit this when I got a wrong result on an instruction that ends up
> > using sve_cntp which counts all bits set in each 64-bit chunk. There
> > might be some other instructions beyond ZIP that generate extra data
> > that would break sve_cntp.  So perhaps it'd be easier to fix sve_cmtp
> > (and hope that it's the only function that uses bits beyond vector
> > length...).
>
> There are quite a few places that assume (and some that assert, such as the
> load/store paths) that there are no predicate bits set beyond VL.
>
> I will fix zip.

Looking at the code I think sve_punpk_p is affected too.

Thanks,

Laurent

>
>
> r~