https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124121
--- Comment #25 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-16 branch has been updated by Tomasz Kaminski <[email protected]>: https://gcc.gnu.org/g:e47727a876ca2adccfab8bb1b4ede8a97326b636 commit r16-9657-ge47727a876ca2adccfab8bb1b4ede8a97326b636 Author: Tomasz KamiÅski <[email protected]> Date: Fri Sep 11 10:23:33 2026 +0200 libstdc++: Remove unecessary std::start_lifetime_as call in inplace_vector [PR124121]. This removes use of std::start_lifetime_as from inplace_vector::_M_init, that was preventing optimizations (see PR124121), it is not required as GCC treats any write to union as potentially changing active member. Furthermore when available __builtin_constexpr_diag is used to emit better error message. TODO comment is also removed, as suggested new call is not supported until clang 23. This backports parts of r17-4164-ga6cb4f45, that does not depend on start_lifetime. libstdc++-v3/ChangeLog: PR libstdc++/124121 * include/std/inplace_vector (inplace_vector::_M_init): Remove unnecessary start_lifetime_as call. Emit error using __builtin_constexpr_diag. Reviewed-by: Jonathan Wakely <[email protected]> Signed-off-by: Tomasz KamiÅski <[email protected]>
