[libcxx-commits] [PATCH] D62233: General shared_ptr cleanup

[Marshall Clow via Phabricator via libcxx-commits]

mclow.lists added a comment.

> stop using compressed_pair to store objects.

Besides breaking the ABI, what's the motivation to stop using `compressed_pair`?
Many allocators are "state-free", and there's no need to actually *store* one of them.
That's the **purpose** of `compressed_pair`, to not store objects that have no state.

given two types `T` and `A`, where `A` has no non-static data members (and no virtual functions), we have

`sizeof(std::pair<T, A>) == sizeof(T) + sizeof(A)` + possible padding.
`sizeof(compressed_pair<T,A>) == sizeof(T)`


Repository:
  rCXX libc++

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62233/new/

https://reviews.llvm.org/D62233