On Wed, 20 Dec 2023, Andre Vieira (lists) wrote:
> Thanks, fully agree with all comments.
>
> gcc/ChangeLog:
>
> PR target/112787
> * tree-vect-generic (type_for_widest_vector_mode): Change function
> to use original vector type and check widest vector mode has at most
> the same number of elements.
> (get_compute_type): Pass original vector type rather than the element
> type to type_for_widest_vector_mode and remove now obsolete check
> for the number of elements.
OK.
Richard.
> On 07/12/2023 07:45, Richard Biener wrote:
> > On Wed, 6 Dec 2023, Andre Vieira (lists) wrote:
> >
> >> Hi,
> >>
> >> This patch addresses the issue reported in PR target/112787 by improving
> >> the
> >> compute type selection. We do this by not considering types with more
> >> elements
> >> than the type we are lowering since we'd reject such types anyway.
> >>
> >> gcc/ChangeLog:
> >>
> >> PR target/112787
> >> * tree-vect-generic (type_for_widest_vector_mode): Add a parameter to
> >> control maximum amount of elements in resulting vector mode.
> >> (get_compute_type): Restrict vector_compute_type to a mode no wider
> >> than the original compute type.
> >>
> >> gcc/testsuite/ChangeLog:
> >>
> >> * gcc.target/aarch64/pr112787.c: New test.
> >>
> >> Bootstrapped and regression tested on aarch64-unknown-linux-gnu and
> >> x86_64-pc-linux-gnu.
> >>
> >> Is this OK for trunk?
> >
> > @@ -1347,7 +1347,7 @@ optimize_vector_constructor (gimple_stmt_iterator
> > *gsi)
> > TYPE, or NULL_TREE if none is found. */
> >
> > Can you improve the function comment? It also doesn't mention OP ...
> >
> > static tree
> > -type_for_widest_vector_mode (tree type, optab op)
> > +type_for_widest_vector_mode (tree type, optab op, poly_int64 max_nunits =
> > 0)
> > {
> > machine_mode inner_mode = TYPE_MODE (type);
> > machine_mode best_mode = VOIDmode, mode;
> > @@ -1371,7 +1371,9 @@ type_for_widest_vector_mode (tree type, optab op)
> > FOR_EACH_MODE_FROM (mode, mode)
> > if (GET_MODE_INNER (mode) == inner_mode
> > && maybe_gt (GET_MODE_NUNITS (mode), best_nunits)
> > - && optab_handler (op, mode) != CODE_FOR_nothing)
> > + && optab_handler (op, mode) != CODE_FOR_nothing
> > + && (known_eq (max_nunits, 0)
> > + || known_lt (GET_MODE_NUNITS (mode), max_nunits)))
> >
> > max_nunits suggests that known_le would be appropriate instead.
> >
> > I see the only other caller with similar "problems":
> >
> > }
> > /* Can't use get_compute_type here, as supportable_convert_operation
> > doesn't necessarily use an optab and needs two arguments. */
> > tree vec_compute_type
> > = type_for_widest_vector_mode (TREE_TYPE (arg_type), mov_optab);
> > if (vec_compute_type
> > && VECTOR_MODE_P (TYPE_MODE (vec_compute_type))
> > && subparts_gt (arg_type, vec_compute_type))
> >
> > so please do not default to 0 but adjust this one as well. It also
> > seems you then can remove the subparts_gt guards on both
> > vec_compute_type uses.
> >
> > I think the API would be cleaner if we'd pass the original vector type
> > we can then extract TYPE_VECTOR_SUBPARTS from, avoiding the extra arg.
> >
> > No?
> >
> > Thanks,
> > Richard.
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
