https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65033
--- Comment #6 from Richard Henderson <rth at gcc dot gnu.org> --- (In reply to Bin Fan from comment #5) > So after the fix, atomic_is_lock_free will always return 0 for > size=3,align=1 atomic struct objects? Yes. > I understand currently libatomic tries to make an atomic object lock-free if > its memory location fit in a certain sized window. So for atomic operations > such as atomic_store where the actual address is passed in, the operation > can be still either lock-free or locked, right? Yes. > I'm wondering if it's standard conforming since the lock-free property > is still per-object, or it can be seen as an optimization, i.e. > atomic_is_lock_free query for the > object returns 0, but atomic operations on the object could be lock-free. My understanding is that it's valid to optimize the operation to lock-free, but since there may exist objects for which we will have to use the lock, the atomic_is_lock_free query must return false.
