Re: [PATCH 15/20] arm: [MVE intrinsics] add unary_acc shape

[Christophe Lyon <christophe.lyon@arm.com>]

On 5/10/23 16:52, Kyrylo Tkachov wrote:
> 
> 
>> -----Original Message-----
>> From: Christophe Lyon <christophe.lyon@arm.com>
>> Sent: Wednesday, May 10, 2023 2:31 PM
>> To: gcc-patches@gcc.gnu.org; Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>;
>> Richard Earnshaw <Richard.Earnshaw@arm.com>; Richard Sandiford
>> <Richard.Sandiford@arm.com>
>> Cc: Christophe Lyon <Christophe.Lyon@arm.com>
>> Subject: [PATCH 15/20] arm: [MVE intrinsics] add unary_acc shape
>>
>> This patch adds the unary_acc shape description.
>>
>> 2022-10-25  Christophe Lyon  <christophe.lyon@arm.com>
>>
>> 	gcc/
>> 	* config/arm/arm-mve-builtins-shapes.cc (unary_acc): New.
>> 	* config/arm/arm-mve-builtins-shapes.h (unary_acc): New.
>> ---
>>   gcc/config/arm/arm-mve-builtins-shapes.cc | 28 +++++++++++++++++++++++
>>   gcc/config/arm/arm-mve-builtins-shapes.h  |  1 +
>>   2 files changed, 29 insertions(+)
>>
>> diff --git a/gcc/config/arm/arm-mve-builtins-shapes.cc b/gcc/config/arm/arm-
>> mve-builtins-shapes.cc
>> index bff1c3e843b..e77a0cc20ac 100644
>> --- a/gcc/config/arm/arm-mve-builtins-shapes.cc
>> +++ b/gcc/config/arm/arm-mve-builtins-shapes.cc
>> @@ -1066,6 +1066,34 @@ struct unary_def : public overloaded_base<0>
>>   };
>>   SHAPE (unary)
>>
>> +/* <S0:twice>_t vfoo[_<t0>](<T0>_t)
>> +
>> +   i.e. a version of "unary" in which the source elements are half the
>> +   size of the destination scalar, but have the same type class.
>> +
>> +   Example: vaddlvq.
>> +   int64_t [__arm_]vaddlvq[_s32](int32x4_t a)
>> +   int64_t [__arm_]vaddlvq_p[_s32](int32x4_t a, mve_pred16_t p) */
>> +struct unary_acc_def : public overloaded_base<0>
>> +{
>> +  void
>> +  build (function_builder &b, const function_group_info &group,
>> +	 bool preserve_user_namespace) const override
>> +  {
>> +    b.add_overloaded_functions (group, MODE_none,
>> preserve_user_namespace);
>> +    build_all (b, "sw0,v0", group, MODE_none, preserve_user_namespace);
>> +  }
>> +
>> +  tree
>> +  resolve (function_resolver &r) const override
>> +  {
>> +    /* FIXME: check that the return value is actually
>> +       twice as wide as arg 0.  */
> 
> Any reason why we can't add that check now?
> I'd rather not add new FIXMEs here...

I understand :-)

That's because the resolver only knows about the arguments, not the 
return value:
   /* The arguments to the overloaded function.  */
   vec<tree, va_gc> &m_arglist;

I kept this like what already exists for AArch64/SVE, but we'll need to 
extend it to handle return values too, so that we can support all 
overloaded forms of vuninitialized
(see https://gcc.gnu.org/pipermail/gcc-patches/2023-April/616003.html)

I meant this extension to be a follow-up work when most intrinsics have 
been converted and the few remaining ones (eg. vuninitialized) needs an 
improved framework.  And that would enable to fix the FIXME.

Thanks,

Christophe


> Thanks,
> Kyrill
> 
>> +    return r.resolve_unary ();
>> +  }
>> +};
>> +SHAPE (unary_acc)
>> +
>>   /* <T0>_t foo_t0[_t1](<T1>_t)
>>
>>      where the target type <t0> must be specified explicitly but the source
>> diff --git a/gcc/config/arm/arm-mve-builtins-shapes.h b/gcc/config/arm/arm-
>> mve-builtins-shapes.h
>> index fc1bacbd4da..c062fe624c4 100644
>> --- a/gcc/config/arm/arm-mve-builtins-shapes.h
>> +++ b/gcc/config/arm/arm-mve-builtins-shapes.h
>> @@ -53,6 +53,7 @@ namespace arm_mve
>>       extern const function_shape *const create;
>>       extern const function_shape *const inherent;
>>       extern const function_shape *const unary;
>> +    extern const function_shape *const unary_acc;
>>       extern const function_shape *const unary_convert;
>>       extern const function_shape *const unary_int32;
>>       extern const function_shape *const unary_int32_acc;
>> --
>> 2.34.1
>