Re: [RISCV] [GNU AS] Possible `vmsge{u}.vx` instruction lowering bug?

[Nelson Chu <nelson@rivosinc.com>]

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Thanks for both your clarifications, committed.

Thanks
Nelson

On Fri, Sep 1, 2023 at 2:37 PM Kiva Oyama <libkernelpanic@gmail.com> wrote:

> >  Is the following expected?
>
> Yes.
>
> > Seems "vd is any" also has the same issue.
>
> I rechecked the spec, for every masked vmsge{u}.vx, the lowered
> instruction is only masked when `vd != v0`.
> So your patch does fix these two problems.
>
> Thank you for clarifying.
>
> Best Regards,
> Kiva Oyama
>
> On Wed, Aug 30, 2023 at 1:51 PM Jan Beulich <jbeulich@suse.com> wrote:
>
>> On 30.08.2023 04:51, Nelson Chu wrote:
>> > Hi Jan,
>> > Thanks for pointing that out.
>> >
>> > Hi Kiva,
>> > Maybe you can send a better patch for this issue if you are interested,
>> > including what Jan suggested.  Thanks :-)
>>
>> Hmm, both of your replies above make me suspect a misunderstanding: I
>> think your patch does exactly what is needed.
>>
>> Jan
>>
>> > On Tue, Aug 29, 2023 at 4:52 PM Jan Beulich <jbeulich@suse.com> wrote:
>> >
>> >> On 29.08.2023 09:59, Nelson Chu wrote:
>> >>> Is the following expected?
>> >>
>> >> I think so, but Kiva - please confirm.
>> >>
>> >>>  Seems "vd is any" also has the same issue.
>> >>
>> >> Right, that's what ...
>> >>
>> >>>> I think this wants fixing alike in binutils: From looking at
>> >>>> vector_macro(),
>> >>>> it appears that emitting the masked form is merely an accident
>> resulting
>> >>>> from the inverted encoding of "masking". In particular, if masking
>> was
>> >>>> indeed meant, I expect code there would be
>> >>>>
>> >>>>                   if (vd == vm)
>> >>>>                     {
>> >>>>                       macro_build (NULL, "vmslt.vx", "Vd,Vt,sVm",
>> vtemp,
>> >>>> vs2, vs1, vm);
>> >>>>                       macro_build (NULL, "vmandnot.mm", "Vd,Vt,Vs",
>> vd,
>> >>>> vm, vtemp);
>> >>>>                     }
>> >>>>                   else
>> >>>>                     ...
>> >>>>
>> >>>> much like it is a few lines down from there. (Apparently the "else"
>> path
>> >>>> omitted above is similarly affected.)
>> >>
>> >> ... I was referring to with the parenthesized sentence.
>> >>
>> >> Jan
>> >>
>> >
>>
>>