On Fri, Oct 25, 2019 at 2:49 PM Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> Although a previous patch allowed mixed vector sizes within a vector
> region, we generally still required equal vector sizes within a vector
> stmt. Specifically, vect_get_vector_types_for_stmt computes two vector
> types: the vector type corresponding to STMT_VINFO_VECTYPE and the
> vector type that determines the minimum vectorisation factor for the
> stmt ("nunits_vectype"). It then required these two types to be
> the same size.
>
> There doesn't seem to be any need for that restriction though. AFAICT,
> all vectorizable_* functions either do their own compatibility checks
> or don't need to do them (because gimple guarantees that the scalar
> types are compatible).
>
> It should always be the case that nunits_vectype has at least as many
> elements as the other vectype, but that's something we can assert for.
>
> I couldn't resist a couple of other tweaks while there:
>
> - there's no need to compute nunits_vectype if its element type is
> the same as STMT_VINFO_VECTYPE's.
>
> - it's useful to distinguish the nunits_vectype from the main vectype
> in dump messages
>
> - when reusing the existing STMT_VINFO_VECTYPE, it's useful to say so
> in the dump, and say what the type is
OK.
Thanks,
Richard.
>
> 2019-10-24 Richard Sandiford <richard.sandif...@arm.com>
>
> gcc/
> * tree-vect-stmts.c (vect_get_vector_types_for_stmt): Don't
> require vectype and nunits_vectype to have the same size;
> instead assert that nunits_vectype has at least as many
> elements as vectype. Don't compute a separate nunits_vectype
> if the scalar type is obviously the same as vectype's.
> Tweak dump messages.
>
> Index: gcc/tree-vect-stmts.c
> ===================================================================
> --- gcc/tree-vect-stmts.c 2019-10-25 13:27:26.205687511 +0100
> +++ gcc/tree-vect-stmts.c 2019-10-25 13:27:32.877640367 +0100
> @@ -11973,7 +11973,12 @@ vect_get_vector_types_for_stmt (stmt_vec
> tree vectype;
> tree scalar_type = NULL_TREE;
> if (STMT_VINFO_VECTYPE (stmt_info))
> - *stmt_vectype_out = vectype = STMT_VINFO_VECTYPE (stmt_info);
> + {
> + *stmt_vectype_out = vectype = STMT_VINFO_VECTYPE (stmt_info);
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_NOTE, vect_location,
> + "precomputed vectype: %T\n", vectype);
> + }
> else
> {
> gcc_assert (!STMT_VINFO_DATA_REF (stmt_info));
> @@ -12005,7 +12010,7 @@ vect_get_vector_types_for_stmt (stmt_vec
>
> if (dump_enabled_p ())
> dump_printf_loc (MSG_NOTE, vect_location,
> - "get vectype for scalar type: %T\n", scalar_type);
> + "get vectype for scalar type: %T\n", scalar_type);
> vectype = get_vectype_for_scalar_type (vinfo, scalar_type);
> if (!vectype)
> return opt_result::failure_at (stmt,
> @@ -12022,42 +12027,38 @@ vect_get_vector_types_for_stmt (stmt_vec
>
> /* Don't try to compute scalar types if the stmt produces a boolean
> vector; use the existing vector type instead. */
> - tree nunits_vectype;
> - if (VECTOR_BOOLEAN_TYPE_P (vectype))
> - nunits_vectype = vectype;
> - else
> + tree nunits_vectype = vectype;
> + if (!VECTOR_BOOLEAN_TYPE_P (vectype)
> + && *stmt_vectype_out != boolean_type_node)
> {
> /* The number of units is set according to the smallest scalar
> type (or the largest vector size, but we only support one
> vector size per vectorization). */
> - if (*stmt_vectype_out != boolean_type_node)
> + HOST_WIDE_INT dummy;
> + scalar_type = vect_get_smallest_scalar_type (stmt_info, &dummy,
> &dummy);
> + if (scalar_type != TREE_TYPE (vectype))
> {
> - HOST_WIDE_INT dummy;
> - scalar_type = vect_get_smallest_scalar_type (stmt_info,
> - &dummy, &dummy);
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_NOTE, vect_location,
> + "get vectype for smallest scalar type: %T\n",
> + scalar_type);
> + nunits_vectype = get_vectype_for_scalar_type (vinfo, scalar_type);
> + if (!nunits_vectype)
> + return opt_result::failure_at
> + (stmt, "not vectorized: unsupported data-type %T\n",
> + scalar_type);
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_NOTE, vect_location, "nunits vectype: %T\n",
> + nunits_vectype);
> }
> - if (dump_enabled_p ())
> - dump_printf_loc (MSG_NOTE, vect_location,
> - "get vectype for scalar type: %T\n", scalar_type);
> - nunits_vectype = get_vectype_for_scalar_type (vinfo, scalar_type);
> }
> - if (!nunits_vectype)
> - return opt_result::failure_at (stmt,
> - "not vectorized: unsupported data-type
> %T\n",
> - scalar_type);
> -
> - if (maybe_ne (GET_MODE_SIZE (TYPE_MODE (vectype)),
> - GET_MODE_SIZE (TYPE_MODE (nunits_vectype))))
> - return opt_result::failure_at (stmt,
> - "not vectorized: different sized vector "
> - "types in statement, %T and %T\n",
> - vectype, nunits_vectype);
> +
> + gcc_assert (*stmt_vectype_out == boolean_type_node
> + || multiple_p (TYPE_VECTOR_SUBPARTS (nunits_vectype),
> + TYPE_VECTOR_SUBPARTS (*stmt_vectype_out)));
>
> if (dump_enabled_p ())
> {
> - dump_printf_loc (MSG_NOTE, vect_location, "vectype: %T\n",
> - nunits_vectype);
> -
> dump_printf_loc (MSG_NOTE, vect_location, "nunits = ");
> dump_dec (MSG_NOTE, TYPE_VECTOR_SUBPARTS (nunits_vectype));
> dump_printf (MSG_NOTE, "\n");
