https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120620
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:b51ca7d2f548ffdad03fa779e3ff7bcc3441ff03 commit r16-2770-gb51ca7d2f548ffdad03fa779e3ff7bcc3441ff03 Author: Patrick Palka <ppa...@redhat.com> Date: Mon Aug 4 16:43:33 2025 -0400 c++: constexpr evaluation of abi::__dynamic_cast [PR120620] r13-3299 changed our internal declaration of __dynamic_cast to reside inside the abi/__cxxabiv1:: namespace instead of the global namespace, matching the real declaration. This inadvertently made us now attempt constexpr evaluation of user-written calls to abi::__dynamic_cast since cxx_dynamic_cast_fn_p now also returns true for them, but we're not prepared to handle arbitrary calls to __dynamic_cast, and therefore ICE. This patch restores cxx_dynamic_cast_fn_p to return true only for synthesized calls to __dynamic_cast, which can be distinguished by DECL_ARTIFICIAL, since apparently the synthesized declaration of __dynamic_cast doesn't get merged with the actual declaration. PR c++/120620 gcc/cp/ChangeLog: * constexpr.cc (cxx_dynamic_cast_fn_p): Return true only for synthesized __dynamic_cast. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/constexpr-dynamic19.C: New test. * g++.dg/cpp2a/constexpr-dynamic1a.C: New test. Reviewed-by: Jason Merrill <ja...@redhat.com>
