Add a partial_integral_type_p helper function

[Martin Sebor]

On 08/18/2017 02:13 AM, Richard Sandiford wrote:
> This patch adds a partial_integral_type_p function, to go along
> with the full_integral_type_p added by the previous patch.
>
> Of the changes that didn't previously have an INTEGRAL_TYPE_P check:
>
> - the convert_to_integer_1 hunks are dominated by a case version
>   of INTEGRAL_TYPE_P.
>
> - the merge_ranges hunk is dominated by an ENUMERAL_TYPE case.
>
> - vectorizable_reduction has the comment:
>
>       /* Do not try to vectorize bit-precision reductions.  */
>
>   and so I think was only concerned with integers.
>
> - vectorizable_assignment has the comment:
>
>       /* We do not handle bit-precision changes.  */
>
>   and the later:
>
>       /* But a conversion that does not change the bit-pattern is ok.  */
>       && !((TYPE_PRECISION (TREE_TYPE (scalar_dest))
> 	    > TYPE_PRECISION (TREE_TYPE (op)))
> 	   && TYPE_UNSIGNED (TREE_TYPE (op)))
>
>   would only make sense if OP is also an integral type.
>
> - vectorizable_shift is inherently restricted to integers.
>
> Tested on aarch64-linux-gnu and x86_64-linux-gnu.  OK to install?
>
> Richard
>
>
> 2017-08-17  Richard Sandiford  <richard.sandiford@linaro.org>
> 	    Alan Hayward  <alan.hayward@arm.com>
> 	    David Sherwood  <david.sherwood@arm.com>
>
> gcc/
> 	* tree.h (partial_integral_type_p): New function.
> 	* convert.c (convert_to_integer_1): Use it.
> 	* expr.c (store_fieldexpand_expr_real_2, expand_expr_real_1): Likewise.
> 	* fold-const.c (merge_ranges): Likewise.
> 	* tree-ssa-math-opts.c (convert_mult_to_fma): Likewise.
> 	* tree-tailcall.c (process_assignment): Likewise.
> 	* tree-vect-loop.c (vectorizable_reduction): Likewise.
> 	* tree-vect-stmts.c (vectorizable_conversion): Likewise.
> 	(vectorizable_assignment, vectorizable_shift): Likewise.
>
> Index: gcc/tree.h
> ===================================================================
> --- gcc/tree.h	2017-08-18 08:35:58.031690315 +0100
> +++ gcc/tree.h	2017-08-18 08:36:07.208306339 +0100
> @@ -5414,4 +5414,13 @@ full_integral_type_p (const_tree t)
>    return INTEGRAL_TYPE_P (t) && scalar_type_is_full_p (t);
>  }
>
> +/* Return true if T is an integral type that has fewer bits than
> +   its underlying mode.  */

May I suggest to rephrase that as "has fewer bits of precision
than..." to make it clear what those bits refer to?  Alternatively.
"type whose precision is less than that of its underlying mode."

> +
> +inline bool
> +partial_integral_type_p (const_tree t)
> +{
> +  return INTEGRAL_TYPE_P (t) && !scalar_type_is_full_p (t);
> +}
> +

Martin