https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109741
--- Comment #15 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:94a311abf783de754f0f1b2d4c1f00a9788e795b commit r14-918-g94a311abf783de754f0f1b2d4c1f00a9788e795b Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue May 16 15:09:20 2023 +0100 libstdc++: Disable cacheline alignment for DJGPP [PR109741] DJGPP (and maybe other targets) uses MAX_OFILE_ALIGNMENT=16 which means that globals (and static objects) can't have alignment greater than 16. This causes an error for the locks defined in src/c++11/shared_ptr.cc because we try to align them to the cacheline size, to avoid false sharing. Add a configure check for the increased alignment, and live with false sharing where we can't increase the alignment. libstdc++-v3/ChangeLog: PR libstdc++/109741 * acinclude.m4 (GLIBCXX_CHECK_ALIGNAS_CACHELINE): Define. * config.h.in: Regenerate. * configure: Regenerate. * configure.ac: Use GLIBCXX_CHECK_ALIGNAS_CACHELINE. * src/c++11/shared_ptr.cc (__gnu_internal::get_mutex): Do not align lock table if not supported. use __GCC_DESTRUCTIVE_SIZE instead of hardcoded 64.
