Re: [AArch64] Enable generation of FRINTNZ instructions

["Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com>]

ping

On 25/11/2021 13:53, Andre Vieira (lists) via Gcc-patches wrote:
>
> On 22/11/2021 11:41, Richard Biener wrote:
>>
>>> On 18/11/2021 11:05, Richard Biener wrote:
>>>> This is a good shout and made me think about something I hadn't 
>>>> before... I
>>>> thought I could handle the vector forms later, but the problem is 
>>>> if I add
>>>> support for the scalar, it will stop the vectorizer. It seems
>>>> vectorizable_call expects all arguments to have the same type, 
>>>> which doesn't
>>>> work with passing the integer type as an operand work around.
>> We already special case some IFNs there (masked load/store and gather)
>> to ignore some args, so that would just add to this set.
>>
>> Richard.
> Hi,
>
> Reworked it to add support of the new IFN to the vectorizer. Was 
> initially trying to make vectorizable_call and 
> vectorizable_internal_function handle IFNs with different inputs more 
> generically, using the information we have in the <IFN>_direct structs 
> regarding what operands to get the modes from. Unfortunately, that 
> wasn't straightforward because of how vectorizable_call assumes 
> operands have the same type and uses the type of the DEF_STMT_INFO of 
> the non-constant operands (either output operand or non-constant 
> inputs) to determine the type of constants. I assume there is some 
> reason why we use the DEF_STMT_INFO and not always use 
> get_vectype_for_scalar_type on the argument types. That is why I ended 
> up with this sort of half-way mix of both, which still allows room to 
> add more IFNs that don't take inputs of the same type, but require 
> adding a bit of special casing similar to the IFN_FTRUNC_INT and 
> masking ones.
>
> Bootstrapped on aarch64-none-linux.
>
> OK for trunk?
>
> gcc/ChangeLog:
>
>         * config/aarch64/aarch64.md (ftrunc<mode><frintnz_mode>2): New 
> pattern.
>         * config/aarch64/iterators.md (FRINTNZ): New iterator.
>         (frintnz_mode): New int attribute.
>         (VSFDF): Make iterator conditional.
>         * internal-fn.def (FTRUNC_INT): New IFN.
>         * internal-fn.c (ftrunc_int_direct): New define.
>         (expand_ftrunc_int_optab_fn): New custom expander.
>         (direct_ftrunc_int_optab_supported_p): New supported_p.
>         * match.pd: Add to the existing TRUNC pattern match.
>         * optabs.def (ftrunc_int): New entry.
>         * stor-layout.h (element_precision): Moved from here...
>         * tree.h (element_precision): ... to here.
>         (element_type): New declaration.
>         * tree.c (element_type): New function.
>         (element_precision): Changed to use element_type.
>         * tree-vect-stmts.c (vectorizable_internal_function): Add 
> support for
>         IFNs with different input types.
>         (vectorizable_call): Teach to handle IFN_FTRUNC_INT.
>         * doc/md.texi: New entry for ftrunc pattern name.
>         * doc/sourcebuild.texi (aarch64_frintzx_ok): New target.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/aarch64/merge_trunc1.c: Adapted to skip if 
> frintNz instruction available.
>         * lib/target-supports.exp: Added arm_v8_5a_frintnzx_ok target.
>         * gcc.target/aarch64/frintnz.c: New test.
>         * gcc.target/aarch64/frintnz_vec.c: New test.