https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94831
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:162c40a4c127cc55d701bb8760e17708d0ca2fe0 commit r10-8021-g162c40a4c127cc55d701bb8760e17708d0ca2fe0 Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue Apr 28 23:26:21 2020 +0100 libstdc++: Fix regression in std::_Construct (PR 94831) By trying to reuse the existing std::_Construct function as a wrapper for std::construct_at I introduced regressions, because changing std::_Construct to return non-void made it ill-formed for array types. The solution is to revert _Construct to its former state, and change allocator_traits::construct to explicitly call construct_at instead. This decouples all the existing callers of _Construct from the new construct_at requirements. PR libstdc++/94831 * include/bits/alloc_traits.h (_S_construct): Restore placement new-expression for C++11/14/17 and call std::construct_at directly for C++20. * include/bits/stl_construct.h (_Construct): Revert to non-constexpr function returning void. * testsuite/20_util/specialized_algorithms/ uninitialized_value_construct/94831.cc: New test. * testsuite/23_containers/vector/cons/94831.cc: New test.
