Re: [PATCH] Fix aarch64 PR 99657: ICE with SVE types used without an error

["Kewen.Lin" <linkw@linux.ibm.com>]

on 2022/12/8 15:43, Richard Sandiford wrote:
> "Kewen.Lin" <linkw@linux.ibm.com> writes:
>> on 2022/12/7 20:55, Richard Sandiford wrote:
>>> "Kewen.Lin" <linkw@linux.ibm.com> writes:
>>>> Hi Richard,
>>>>
>>>> on 2022/12/7 17:16, Richard Sandiford wrote:
>>>>> "Kewen.Lin" <linkw@linux.ibm.com> writes:
>>>>>> Hi,
>>>>>>
>>>>>> In the recent discussion on how to make some built-in type only valid for
>>>>>> some target features efficiently[1], Andrew mentioned this patch which he
>>>>>> made previously (Thanks!).  I confirmed it can help rs6000 related issue,
>>>>>> and noticed PR99657 is still opened, so I think we still want this to
>>>>>> be reviewed.
>>>>>
>>>>> But does it work for things like:
>>>>>
>>>>>     void f(foo_t *x, foo_t *y) { *x = *y; }
>>>>>
>>>>> where no variables are being created with foo_t type?
>>>>>
>>>>
>>>> I think it can work for this case as it touches build_indirect_ref.
>>>
>>> Ah, ok.  But indirecting through a pointer doesn't seem to match
>>> TCTX_AUTO_STORAGE.
>>>
>>
>> Indeed. :)
>>
>>> I guess another case is where there are global variables of the type
>>> that you want to forbid, compiled while the target feature is enabled,
>>> and then a function tries to access those variables with the target
>>> feature locally disabled (through a pragma or attribute).  Does that
>>> case work?
>>>
>>
>> Thanks for pointing out this, I tried with the below test case:
>>
>> __vector_quad a1;
>> __vector_quad a2;
>>
>> __attribute__((target("cpu=power8")))
>> void foo ()
>> {
>>   a2 = a3;
>> }
>>
>> the verify_type_context doesn't catch it as you suspected, I think
>> it needs some enhancements somewhere.
> 
> FWIW, another possible case is:
> 
>   foo_t f();
>   void g(foo_t);
>   void h() { g(f()); }
> 
> I'm not aware of any verify_type_context checks that would catch this
> for SVE (since it's valid for SVE types).


OK, thanks for the information, MMA built-in types are not allowed to be
used in function arguments, by hacking with the restriction relaxing, I
confirm the verify_type_context check can't catch this case.

BR,
Kewen