https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101539
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Attachment #51192|0 |1
is obsolete| |
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 51241
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51241&action=edit
gcc12-pr101539.patch
Updated __is_layout_compatible trait patch that now also implements
__builtin_is_corresponding_member. For now it implements the IMHO buggy but
standard definition of layout-compatible and std::is_layout_compatible
comments,
including ignoring of alignment differences, mishandling of bitfields in unions
and [[no_unique_address]] issues with empty classes.
For __builtin_is_corresponding_member, it will sorry if corresponding members
could have different offsets (doesn't do so during constant evaluation but
unless one uses the builtin directly, even using std::is_corresponding_member
in constant expressions only will result in instantiation of the template and
the code in the template doesn't have constant arguments and so can emit
sorry).
For anonymous structs (GCC extension) it will recurse into the anonymous
structs. For anonymous unions it will emit another sorry if it can't prove
such
member types can't appear in the anonymous unions or anonymous aggregates in
that union, because corresponding member is defined only using common initial
sequence which is only defined for std-layout non-union class types.
