On Thu, Nov 30, 2017 at 12:55 PM, Bernd Edlinger
<[email protected]> wrote:
> On 11/30/17 18:29, Jason Merrill wrote:
>> On Thu, Nov 30, 2017 at 11:07 AM, Bernd Edlinger
>> <[email protected]> wrote:
>>> On 11/30/17 16:45, Jason Merrill wrote:
>>>> On Thu, Nov 30, 2017 at 10:14 AM, Bernd Edlinger
>>>> <[email protected]> wrote:
>>>>> On 11/29/17 22:57, Jason Merrill wrote:
>>>>>> On 10/09/2017 06:30 PM, Bernd Edlinger wrote:
>>>>
>>>>>>> + if (INTEGRAL_TYPE_P (t1)
>>>>>>> + && INTEGRAL_TYPE_P (t2)
>>>>>>> + && TYPE_PRECISION (t1) == TYPE_PRECISION (t2)
>>>>>>> + && (TYPE_UNSIGNED (t1) == TYPE_UNSIGNED (t2)
>>>>>>> + || TYPE_PRECISION (t1) >= TYPE_PRECISION (integer_type_node)))
>>>>>>> + return true;
>>>>>>
>>>>>> This section needs a comment explaining what you're allowing and why.
>>>>>
>>>>> Okay. I will add a comment here:
>>>>>
>>>>> /* The signedness of the parameter matters only when an integral
>>>>> type smaller than int is promoted to int, otherwise only the
>>>>> precision of the parameter matters.
>>>>> This check should make sure that the callee does not see
>>>>> undefined values in argument registers. */
>>>>
>>>> If we're thinking about argument promotion, should this use
>>>> type_passed_as rather than assume promotion to int?
>>>
>>> I don't know, it is only a heuristic after all, and even if there is no
>>> warning for a bogus type cast that does not mean any
>>> correctness-guarantee at all.
>>>
>>> Would type_passed_as make any difference for integral types?
>>
>> Yes, type_passed_as expresses promotion to int on targets that want
>> that behavior.
>>
>
> Hmm, I see, mostly arm, sh and msp430 (whatever that may be).
>
> So how would you like this:
>
> if (INTEGRAL_TYPE_P (t1)
> && INTEGRAL_TYPE_P (t2)
> && TYPE_PRECISION (t1) == TYPE_PRECISION (t2)
> && (TYPE_UNSIGNED (t1) == TYPE_UNSIGNED (t2)
> || !targetm.calls.promote_prototypes (t1)
> || !targetm.calls.promote_prototypes (t2)
> || TYPE_PRECISION (t1) >= TYPE_PRECISION (integer_type_node)))
I was thinking
&& (TYPE_UNSIGNED (t1) == TYPE_UNSIGNED (t2)
|| type_passed_as (t1) == t1))
Jason
