Re: [AArch64] Enable generation of FRINTNZ instructions

[Richard Biener <rguenther@suse.de>]

On Mon, 10 Jan 2022, Andre Vieira (lists) wrote:

> Yeah seems I forgot to send the latest version, my bad.
> 
> Bootstrapped on aarch64-none-linux.
> 
> OK for trunk?

The match.pd part looks OK to me.

Thanks,
Richard.

> 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.
> 
> On 03/01/2022 12:18, Richard Biener wrote:
> > On Wed, 29 Dec 2021, Andre Vieira (lists) wrote:
> >
> >> Hi Richard,
> >>
> >> Thank you for the review, I've adopted all above suggestions downstream, I
> >> am
> >> still surprised how many style things I still miss after years of gcc
> >> development :(
> >>
> >> On 17/12/2021 12:44, Richard Sandiford wrote:
> >>>> @@ -3252,16 +3257,31 @@ vectorizable_call (vec_info *vinfo,
> >>>>          rhs_type = unsigned_type_node;
> >>>>        }
> >>>>    -  int mask_opno = -1;
> >>>> +  /* The argument that is not of the same type as the others.  */
> >>>> +  int diff_opno = -1;
> >>>> +  bool masked = false;
> >>>>      if (internal_fn_p (cfn))
> >>>> -    mask_opno = internal_fn_mask_index (as_internal_fn (cfn));
> >>>> +    {
> >>>> +      if (cfn == CFN_FTRUNC_INT)
> >>>> +	/* For FTRUNC this represents the argument that carries the type of
> >>>> the
> >>>> +	   intermediate signed integer.  */
> >>>> +	diff_opno = 1;
> >>>> +      else
> >>>> +	{
> >>>> +	  /* For masked operations this represents the argument that carries
> >>>> the
> >>>> +	     mask.  */
> >>>> +	  diff_opno = internal_fn_mask_index (as_internal_fn (cfn));
> >>>> +	  masked = diff_opno >=  0;
> >>>> +	}
> >>>> +    }
> >>> I think it would be cleaner not to process argument 1 at all for
> >>> CFN_FTRUNC_INT.  There's no particular need to vectorise it.
> >> I agree with this,  will change the loop to continue for argument 1 when
> >> dealing with non-masked CFN's.
> >>
> >>>>    	}
> >>>> […]
> >>>> diff --git a/gcc/tree.c b/gcc/tree.c
> >>>> index
> >>>> 845228a055b2cfac0c9ca8c0cda1b9df4b0095c6..f1e9a1eb48769cb11aa69730e2480ed5522f78c1
> >>>> 100644
> >>>> --- a/gcc/tree.c
> >>>> +++ b/gcc/tree.c
> >>>> @@ -6645,11 +6645,11 @@ valid_constant_size_p (const_tree size,
> >>>> cst_size_error *perr /* = NULL */)
> >>>>      return true;
> >>>>    }
> >>>>    
> >>>> -/* Return the precision of the type, or for a complex or vector type the
> >>>> -   precision of the type of its elements.  */
> >>>> +/* Return the type, or for a complex or vector type the type of its
> >>>> +   elements.  */
> >>>>    -unsigned int
> >>>> -element_precision (const_tree type)
> >>>> +tree
> >>>> +element_type (const_tree type)
> >>>>    {
> >>>>      if (!TYPE_P (type))
> >>>>        type = TREE_TYPE (type);
> >>>> @@ -6657,7 +6657,16 @@ element_precision (const_tree type)
> >>>>      if (code == COMPLEX_TYPE || code == VECTOR_TYPE)
> >>>>        type = TREE_TYPE (type);
> >>>>    -  return TYPE_PRECISION (type);
> >>>> +  return (tree) type;
> >>> I think we should stick a const_cast in element_precision and make
> >>> element_type take a plain “type”.  As it stands element_type is an
> >>> implicit const_cast for many cases.
> >>>
> >>> Thanks,
> >> Was just curious about something here, I thought the purpose of having
> >> element_precision (before) and element_type (now) take a const_tree as an
> >> argument was to make it clear we aren't changing the input type. I
> >> understand
> >> that as it stands element_type could be an implicit const_cast (which I
> >> should
> >> be using rather than the '(tree)' cast), but that's only if 'type' is a
> >> type
> >> that isn't complex/vector, either way, we are conforming to the promise
> >> that
> >> we aren't changing the incoming type, what the caller then does with the
> >> result is up to them no?
> >>
> >> I don't mind making the changes, just trying to understand the reasoning
> >> behind it.
> >>
> >> I'll send in a new patch with all the changes after the review on the
> >> match.pd
> >> stuff.
> > I'm missing an updated patch after my initial review of the match.pd
> > stuff so not sure what to review.  Can you re-post and updated patch?
> >
> > Thanks,
> > Richard.
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev; HRB 36809 (AG Nuernberg)