Re: [AArch64] Enable generation of FRINTNZ instructions

[Richard Biener <rguenther@suse.de>]

On Mon, 22 Nov 2021, Andre Vieira (lists) wrote:

> 
> On 18/11/2021 11:05, Richard Biener wrote:
> >
> > @@ -3713,12 +3713,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >      trapping behaviour, so require !flag_trapping_math. */
> >   #if GIMPLE
> >   (simplify
> > -   (float (fix_trunc @0))
> > -   (if (!flag_trapping_math
> > -       && types_match (type, TREE_TYPE (@0))
> > -       && direct_internal_fn_supported_p (IFN_TRUNC, type,
> > -                                         OPTIMIZE_FOR_BOTH))
> > -      (IFN_TRUNC @0)))
> > +   (float (fix_trunc@1 @0))
> > +   (if (types_match (type, TREE_TYPE (@0)))
> > +    (if (TYPE_SIGN (TREE_TYPE (@1)) == SIGNED
> > +        && direct_internal_fn_supported_p (IFN_FTRUNC_INT, type,
> > +                                           TREE_TYPE (@1),
> > OPTIMIZE_FOR_BOTH))
> > +     (with {
> > +      tree int_type = TREE_TYPE (@1);
> > +      unsigned HOST_WIDE_INT max_int_c
> > +       = (1ULL << (element_precision (int_type) - 1)) - 1;
> >
> > That's only half-way supporting vector types I fear - you use
> > element_precision but then build a vector integer constant
> > in an unsupported way.  I suppose vector support isn't present
> > for arm?  The cleanest way would probably be to do
> >
> >         tree int_type = element_type (@1);
> >
> > with providing element_type in tree.[ch] like we provide
> > element_precision.
> 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.