Re: Add a partial_integral_type_p helper function

[Jeff Law <law at redhat dot com>]

On 08/25/2017 10:48 AM, Martin Sebor wrote:
> 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."
Can't hurt to be a bit more precise for those who haven't had the
pleasure of dealing with partial modes.

Jeff