https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86127
--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Wed Jul 4 13:59:42 2018 New Revision: 262411 URL: https://gcc.gnu.org/viewcvs?rev=262411&root=gcc&view=rev Log: PR libstdc++/86127 avoid unnecessary allocator conversions There is no need to use an allocator of the correct value_type when calling allocator_traits::construct and allocator_traits::destroy. The existing node allocator can be used, instead of constructing a new allocator object every time. There's also no benefit to using __gnu_cxx::__alloc_traits instead of std::allocator_traits to get the pointer and const_pointer types. std::forward_list is only available for C++11 and later, when std::allocator_traits is available too. Backport from mainline 2018-06-13 Jonathan Wakely <jwak...@redhat.com> PR libstdc++/86127 * include/bits/forward_list.h (_Fwd_list_base::_Tp_alloc_type): Remove unused typedef. (_Fwd_list_base::_M_create_node, _Fwd_list_base::_M_erase_after): Use node allocator to create and destroy elements. (forward_list::_Tp_alloc_type): Remove unused typedef. (forward_list::_Alloc_traits): Use allocator_traits instead of __gnu_cxx::__alloc_traits. * include/bits/forward_list.tcc (_Fwd_list_base::_M_erase_after): Use node allocator to create and destroy elements. Modified: branches/gcc-7-branch/libstdc++-v3/ChangeLog branches/gcc-7-branch/libstdc++-v3/include/bits/forward_list.h branches/gcc-7-branch/libstdc++-v3/include/bits/forward_list.tcc
