http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59569
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Bingfeng Mei from comment #9)
> Seems simple patch is to just bypass permutation for constant operand as
> vec_oprnd is a constant vector with identical elements.
>
> Index: tree-vect-stmts.c
> ===================================================================
> --- tree-vect-stmts.c (revision 206176)
> +++ tree-vect-stmts.c (working copy)
> @@ -5353,7 +5353,8 @@ vectorizable_store (gimple stmt, gimple_
> set_ptr_info_alignment (get_ptr_info (dataref_ptr), align,
> misalign);
>
> - if (negative)
> + if (negative
> + && !CONSTANT_CLASS_P (gimple_assign_rhs1 (stmt)))
> {
> tree perm_mask = perm_mask_for_reverse (vectype);
> tree perm_dest
I think checking dt == vect_constant_def || dt == vect_external_def would be
more appropriate. But, IMNSHO you don't need to check at the analysis phase
!perm_mask_for_reverse (vectype)
either.
