https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113200
--- Comment #12 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:26a9e8cee4d20e5b08c0336439c8f69a2f06af1c commit r12-10090-g26a9e8cee4d20e5b08c0336439c8f69a2f06af1c Author: Jonathan Wakely <jwak...@redhat.com> Date: Wed Jan 3 15:01:09 2024 +0000 libstdc++: Fix std::char_traits<C>::move [PR113200] The current constexpr implementation of std::char_traits<C>::move relies on being able to compare the pointer parameters, which is not allowed for unrelated pointers. We can use __builtin_constant_p to determine whether it's safe to compare the pointers directly. If not, then we know the ranges must be disjoint and so we can use char_traits<C>::copy to copy forwards from the first character to the last. If the pointers can be compared directly, then we can simplify the condition for copying backwards to just two pointer comparisons. libstdc++-v3/ChangeLog: PR libstdc++/113200 * include/bits/char_traits.h (__gnu_cxx::char_traits::move): Use __builtin_constant_p to check for unrelated pointers that cannot be compared during constant evaluation. * testsuite/21_strings/char_traits/requirements/113200.cc: New test. (cherry picked from commit 15cc291887dc9dd92b2c93f4545e20eb6c190122)
