On 5/10/19 3:38 PM, Jonathan Wakely wrote:
This seems generally OK, but ...
On Fri, 10 May 2019, 05:59 François Dumont wrote:
I remove several _M_map != nullptr checks cause in current
implementation it can't be null. I have several patches following this
one to support it but in this case we will be using a different code path.
You can't remove those checks. If _M_map can ever be null now or in
the future, then we need the checks. Otherwise code compiled today
would break if passed a deque compiled with a future GCC that allows
the map to be null.
I'm curious how you plan to support it though, I don't think it's
possible without an ABI break.
No miracle, I plan to propose it only in versioned namespace mode, it
does break ABI.
But in this implementation those current checks are useless, I'll double
check.
(_Deque_base::_Deque_impl::_M_move_impl()): Remove _M_impl._M_map
check.
_M_move_impl and the constructor that calls it can be removed
completely, because https://cplusplus.github.io/LWG/issue2593 means
that the same allocator can still be used after moving from it. That
function only exists to handle the case where an allocator changes
value after being moved from.
Good, I'll cleanup that and propose a new patch.
François
