Excerpts from Kewen.Lin's message of Juni 4, 2024 5:17 am:
> Hi Iain,
>
> on 2024/6/3 22:39, Iain Buclaw wrote:
>> Excerpts from Kewen.Lin's message of Juni 3, 2024 10:57 am:
>>> Hi Iain,
>>>
>>> on 2024/6/3 16:40, Iain Buclaw wrote:
>>>> Excerpts from Kewen Lin's message of Juni 3, 2024 5:00 am:
>>>>> Joseph pointed out "floating types should have their mode,
>>>>> not a poorly defined precision value" in the discussion[1],
>>>>> as he and Richi suggested, the existing macros
>>>>> {FLOAT,{,LONG_}DOUBLE}_TYPE_SIZE will be replaced with a
>>>>> hook mode_for_floating_type. To be prepared for that, this
>>>>> patch is to replace use of LONG_DOUBLE_TYPE_SIZE in d with
>>>>> TYPE_PRECISION of long_double_type_node.
>>>>>
>>>>> [1] https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651209.html
>>>>>
>>>>
>>>> Thanks, one question though: Is TYPE_PRECISION really equivalent to
>>>> LONG_DOUBLE_TYPE_SIZE?
>>>
>>> Yes, it's guaranteed by the code in build_common_tree_nodes:
>>>
>>> long_double_type_node = make_node (REAL_TYPE);
>>> TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE;
>>> layout_type (long_double_type_node);
>>>
>>> , the macro LONG_DOUBLE_TYPE_SIZE is assigned to TYPE_PRECISION of
>>> long_double_type_node, layout_type will only pick up one mode as
>>> the given precision and won't change it.
>>>
>>>>
>>>> Unless LONG_DOUBLE_TYPE_SIZE was poorly named to begin with, I'd assume
>>>> the answer to be "no".
>>>
>>> I'm afraid it's poorly named before.
>>>
>>
>> Thanks for confirming Kewen.
>>
>> I suspect then that this code is incorrectly using this macro, and it
>> should instead be using:
>>
>> int_size_in_bytes(long_double_type_node)
>>
>> as any padding should be considered as part of the overall type size for
>> the purpose that this field serves in the D part of the front-end.
>
> Got it, thanks for the explanation and suggestion.
>
>>
>> Are you able to update the patch this way instead? Otherwise I'm happy
>> to push the change instead.
>
> Sure, updated as below:
>
Thanks!
This is OK to apply any time.
Iain.
