On Mon, Aug 21, 2017 at 12:59 AM, Richard Biener
<richard.guent...@gmail.com> wrote:
> On Sat, Aug 19, 2017 at 10:18 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> Don't override alignment specified by user with the same value to
>> preserve TYPE_USER_ALIGN. This fixes PR 53037 tests on Sparc.
>>
>> Does it look right?
>
> Doesn't match do_type_align so it introduces inconsistencies. The
> documentation
> for TYPE_USER_ALIGN doesn't specify when both cases conflict:
>
> /* 1 if the alignment for this type was requested by "aligned" attribute,
> 0 if it is the default for this type. */
>
> Note that for example the vectorizer looks at DECL_USER_ALIGN (for
> non-field-decls)
> to decide whether it can increase alignment.
>
> Richard.
>
>>
>> H.J.
>> --
>> * stor-layout.c (finalize_type_size): Don't override alignment
>> specified by user with the same value.
>> ---
>> gcc/stor-layout.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
>> index 3028d55773a..6dd605810ac 100644
>> --- a/gcc/stor-layout.c
>> +++ b/gcc/stor-layout.c
>> @@ -1784,7 +1784,7 @@ finalize_type_size (tree type)
>>
>> /* Don't override a larger alignment requirement coming from a user
>> alignment of one of the fields. */
>> - if (mode_align >= TYPE_ALIGN (type))
>> + if (mode_align > TYPE_ALIGN (type))
>> {
>> SET_TYPE_ALIGN (type, mode_align);
>> TYPE_USER_ALIGN (type) = 0;
>> --
>> 2.13.5
>>
According to Eric:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53037#c32
"if (mode_align >= TYPE_ALIGN (type))" was intentional. I am
not familiar with STRICT_ALIGNMENT target and there is no
testcase to show why it is needed.
--
H.J.
