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.
>
> i.e: TYPE_PRECISION = 80, but LONG_DOUBLE_TYPE_SIZE = 96 or 128.
>From what I interpreted from the code, it should never happen.
BR,
Kewen
