Re: [PATCH RESEND v2] Aarch64: Allow explicit size specifier for predicate operand of {sq, uq, }{incp, decp}

[Shaokun Zhang <zhangshaokun@hisilicon.com>]

Hi,

On 2022/3/10 19:50, Jan Beulich wrote:
> On 10.03.2022 12:33, Shaokun Zhang wrote:
>> On 2022/3/10 18:38, Jan Beulich wrote:
>>> On 10.03.2022 10:38, Shaokun Zhang wrote:
>>>> Hi Jan,
>>>
>>> Despite this, ...
>>>
>>>> On 2022/3/2 15:36, Shaokun Zhang wrote:
>>>>> On 2022/2/21 21:13, Jan Beulich wrote:
>>>>>> On 16.02.2022 01:53, Shaokun Zhang wrote:
>>>>>>> --- a/gas/testsuite/gas/aarch64/sve-movprfx_23.d
>>>>>>> +++ b/gas/testsuite/gas/aarch64/sve-movprfx_23.d
>>>>>>> @@ -9,29 +9,29 @@ Disassembly of section .*:
>>>>>>>  
>>>>>>>  0+ <.*>:
>>>>>>>  [^:]+:	04512461 	movprfx	z1.h, p1/m, z3.h
>>>>>>> -[^:]+:	256c8021 	incp	z1.h, p1  // note: merging predicate expected due to preceding `movprfx' at operand 2
>>>>>>> +[^:]+:	256c8021 	incp	z1.h, p1.h  // note: merging predicate expected due to preceding `movprfx' at operand 2
>>>>>>
>>>>>> I have a more general question here: Couldn't the spec make optional the
>>>>>> use of all the same size specifiers when there are multiple, same element
>>>>>> size operands? One such suffix of course needs to be there to disambiguate
>>>>>
>>>>> We are not from ARM SPEC group and don't know the exact considerations for
>>>>> the forbidden omitting suffix. We guess people will have different answers from
>>>>> different points of view.
>>>>>
>>>>> >From our point of view,  a suffix makes the assembly more consistent with the
>>>>> scalar versions of `incp`, e.g. `incp x1, p2.b`. And the predicate register acts more
>>>>> like a vector register within this instruction, with suffix, the addend for each element
>>>>> is clear once reading the assembly string.
>>>>>
>>>>> Not sure that anyone from ARM in the mail-list can give more hints or thoughts.
>>>>>
>>>>
>>>> No any more comments from Arm guys.
>>>>
>>>> Is it ok for trunk?
>>>
>>> ... I assume you understand that I'm not in the position to give you the
>>> wanted "okay"?
>>
>> Apologies that I don't follow it completely, do you mean that does it need
>> someone to agree and take it? Or we need more comments?
> 
> Well, as for any patch a maintainer of the code needs to give you their okay.
> 

Oh, Got it, I will loop the AARCH64 maintainers.

Thanks Jan.

> Jan
> 
> .
>