On Fri, Oct 25, 2019 at 2:41 PM Richard Sandiford
<richard.sandif...@arm.com> wrote:
>
> Some callers of get_same_sized_vectype were dealing with operands that
> are constant or defined externally, and so have no STMT_VINFO_VECTYPE
> available. Under the current model, using get_same_sized_vectype for
> that case is equivalent to using get_vectype_for_scalar_type, since
> get_vectype_for_scalar_type always returns vectors of the same size,
> once a size is fixed.
>
> Using get_vectype_for_scalar_type is arguably more obvious though:
> if we're using the same scalar type as we would for internal
> definitions, we should use the same vector type too. (Constant and
> external definitions sometimes let us change the original scalar type
> to a "nicer" scalar type, but that isn't what's happening here.)
>
> This is a prerequisite to supporting multiple vector sizes in the same
> vec_info.
This might change the actual type we get back, IIRC we mass-changed
it in the opposite direction from your change in the past, because it's
more obvious to relate the type used to another vector type on the
stmt. So isn't it better to use the new related_vector_type thing here?
Richard.
>
> 2019-10-24 Richard Sandiford <richard.sandif...@arm.com>
>
> gcc/
> * tree-vect-stmts.c (vectorizable_call): If an operand is
> constant or external, use get_vectype_for_scalar_type
> rather than get_same_sized_vectype to get its vector type.
> (vectorizable_conversion, vectorizable_shift): Likewise.
> (vectorizable_operation): Likewise.
>
> Index: gcc/tree-vect-stmts.c
> ===================================================================
> --- gcc/tree-vect-stmts.c 2019-10-25 13:27:19.313736209 +0100
> +++ gcc/tree-vect-stmts.c 2019-10-25 13:27:22.985710263 +0100
> @@ -3308,10 +3308,10 @@ vectorizable_call (stmt_vec_info stmt_in
> return false;
> }
> }
> - /* If all arguments are external or constant defs use a vector type with
> - the same size as the output vector type. */
> + /* If all arguments are external or constant defs, infer the vector type
> + from the scalar type. */
> if (!vectype_in)
> - vectype_in = get_same_sized_vectype (rhs_type, vectype_out);
> + vectype_in = get_vectype_for_scalar_type (vinfo, rhs_type);
> if (vec_stmt)
> gcc_assert (vectype_in);
> if (!vectype_in)
> @@ -4800,10 +4800,10 @@ vectorizable_conversion (stmt_vec_info s
> }
> }
>
> - /* If op0 is an external or constant defs use a vector type of
> - the same size as the output vector type. */
> + /* If op0 is an external or constant def, infer the vector type
> + from the scalar type. */
> if (!vectype_in)
> - vectype_in = get_same_sized_vectype (rhs_type, vectype_out);
> + vectype_in = get_vectype_for_scalar_type (vinfo, rhs_type);
> if (vec_stmt)
> gcc_assert (vectype_in);
> if (!vectype_in)
> @@ -5564,10 +5564,10 @@ vectorizable_shift (stmt_vec_info stmt_i
> "use not simple.\n");
> return false;
> }
> - /* If op0 is an external or constant def use a vector type with
> - the same size as the output vector type. */
> + /* If op0 is an external or constant def, infer the vector type
> + from the scalar type. */
> if (!vectype)
> - vectype = get_same_sized_vectype (TREE_TYPE (op0), vectype_out);
> + vectype = get_vectype_for_scalar_type (vinfo, TREE_TYPE (op0));
> if (vec_stmt)
> gcc_assert (vectype);
> if (!vectype)
> @@ -5666,7 +5666,7 @@ vectorizable_shift (stmt_vec_info stmt_i
> "vector/vector shift/rotate found.\n");
>
> if (!op1_vectype)
> - op1_vectype = get_same_sized_vectype (TREE_TYPE (op1), vectype_out);
> + op1_vectype = get_vectype_for_scalar_type (vinfo, TREE_TYPE (op1));
> incompatible_op1_vectype_p
> = (op1_vectype == NULL_TREE
> || maybe_ne (TYPE_VECTOR_SUBPARTS (op1_vectype),
> @@ -5997,8 +5997,8 @@ vectorizable_operation (stmt_vec_info st
> "use not simple.\n");
> return false;
> }
> - /* If op0 is an external or constant def use a vector type with
> - the same size as the output vector type. */
> + /* If op0 is an external or constant def, infer the vector type
> + from the scalar type. */
> if (!vectype)
> {
> /* For boolean type we cannot determine vectype by
> @@ -6018,7 +6018,7 @@ vectorizable_operation (stmt_vec_info st
> vectype = vectype_out;
> }
> else
> - vectype = get_same_sized_vectype (TREE_TYPE (op0), vectype_out);
> + vectype = get_vectype_for_scalar_type (vinfo, TREE_TYPE (op0));
> }
> if (vec_stmt)
> gcc_assert (vectype);
