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:
Subject: [PATCH 02/52] d: Replace use of LONG_DOUBLE_TYPE_SIZE
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 remove the only one use of LONG_DOUBLE_TYPE_SIZE
in d. Iain found that LONG_DOUBLE_TYPE_SIZE is poorly named
and used incorrectly before, so this patch follows his advice
with int_size_in_bytes.
[1] https://gcc.gnu.org/pipermail/gcc-patches/2024-May/651209.html
Co-authored-by: Iain Buclaw <ibuc...@gdcproject.org>
gcc/d/ChangeLog:
* d-target.cc (Target::_init): Use int_size_in_bytes of
long_double_type_node to replace the expression with
LONG_DOUBLE_TYPE_SIZE for c.long_doublesize assignment.
---
gcc/d/d-target.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/d/d-target.cc b/gcc/d/d-target.cc
index 127b9d7ce7c..dd46e535891 100644
--- a/gcc/d/d-target.cc
+++ b/gcc/d/d-target.cc
@@ -163,7 +163,7 @@ Target::_init (const Param &)
this->c.intsize = (INT_TYPE_SIZE / BITS_PER_UNIT);
this->c.longsize = (LONG_TYPE_SIZE / BITS_PER_UNIT);
this->c.long_longsize = (LONG_LONG_TYPE_SIZE / BITS_PER_UNIT);
- this->c.long_doublesize = (LONG_DOUBLE_TYPE_SIZE / BITS_PER_UNIT);
+ this->c.long_doublesize = int_size_in_bytes (long_double_type_node);
this->c.wchar_tsize = (WCHAR_TYPE_SIZE / BITS_PER_UNIT);
this->c.bitFieldStyle = targetm.ms_bitfield_layout_p (unknown_type_node)
--
2.43.0
BR,
Kewen
