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Re: [PATCH] Fix PR82255 (vectorizer cost model overcounts some vector load costs)
Bill Schmidt <wschmidt@linux.vnet.ibm.com> writes:
> Index: gcc/tree-vect-stmts.c
> ===================================================================
> --- gcc/tree-vect-stmts.c (revision 252760)
> +++ gcc/tree-vect-stmts.c (working copy)
> @@ -1091,8 +1091,19 @@ vect_model_load_cost (stmt_vec_info stmt_info, int
> prologue_cost_vec, body_cost_vec, true);
> if (memory_access_type == VMAT_ELEMENTWISE
> || memory_access_type == VMAT_STRIDED_SLP)
> - inside_cost += record_stmt_cost (body_cost_vec, ncopies, vec_construct,
> - stmt_info, 0, vect_body);
> + {
> + int group_size = GROUP_SIZE (stmt_info);
> + int nunits = TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info));
> + if (group_size < nunits)
> + {
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_NOTE, vect_location,
> + "vect_model_load_cost: vec_construct required");
> + inside_cost += record_stmt_cost (body_cost_vec, ncopies,
> + vec_construct, stmt_info, 0,
> + vect_body);
> + }
> + }
>
> if (dump_enabled_p ())
> dump_printf_loc (MSG_NOTE, vect_location,
This feels like we've probably got the wrong memory_access_type.
If it's a just a contiguous load then it should be VMAT_CONTIGUOUS
instead.
Thanks,
Richard