On Sun, Mar 13, 2022 at 12:39 AM Marc Glisse via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Fri, 11 Mar 2022, Roger Sayle wrote:
>
> +(match vec_same_elem_p
> + CONSTRUCTOR@0
> + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME
> + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) :
> @0))))
>
> Ah, I didn't remember we needed that, we don't seem to be very consistent
> about it. Probably for this reason, the transformation "Prefer vector1 <<
> scalar to vector1 << vector2" does not match
>
> typedef int vec __attribute__((vector_size(16)));
> vec f(vec a, int b){
> vec bb = { b, b, b, b };
> return a << bb;
> }
>
> which is only optimized at vector lowering time.
Few more comments - since match.pd is matching in match.pd order the
(match vec_same_elem_p
@0
(...))
should come last. Please use
+(match vec_same_elem_p
+ CONSTRUCTOR@0
(if (TREE_CODE (@0) == SSA_NAME
&& uniform_vector_p (...
since otherwise we'll try uniform_vector_p twice on all CTORs (that
are not uniform).
> +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). */
> +(for plusminus (plus minus)
> + (simplify
> + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4)
> + (plusminus (mult (vec_perm @1 @1 @3) @2) @4)))
>
> Don't you want :s on mult and vec_perm?
Yes. Also for plus you want :c on it , likewise you want :c on the
mult. The :c
on the plus will require splitting the plus and minus case :/
Otherwise looks reasonable.
Richard.
>
> --
> Marc Glisse
