https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109405
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
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Keywords| |ABI
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is expected. The unique_ptr implementation uses tuple<int*, SF> which is
similarly dependent on whether the tuple elements are final or not. Originally,
that was because we used inheritance in tuple, in order to take advantage of
the empty-base class optimization. Obviously we can't use inheritance for final
types.
These days we do not use inheritance, we use the [[no_unique_address]]
attribute so that empty tuple elements take no space. But to avoid an ABI
incompatibility with previous versions of GCC, the attribute is only used for
non-final types.
There's no way to fix this without breaking the library's ABI.
