https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117317
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:5ff9e21c1ec81f8288e74679547e56051e051975 commit r15-5043-g5ff9e21c1ec81f8288e74679547e56051e051975 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Nov 8 13:36:05 2024 +0100 c++: Fix ICE on constexpr virtual function [PR117317] Since C++20 virtual methods can be constexpr, and if they are constexpr evaluated, we choose tentative_decl_linkage for those defer their output and decide at_eof again. On the following testcases we ICE though, because if expand_or_defer_fn_1 decides to use tentative_decl_linkage, it returns true and the caller in that case cals emit_associated_thunks, where use_thunk which it calls asserts DECL_INTERFACE_KNOWN on the thunk destination, which isn't the case for tentative_decl_linkage. The following patch fixes the ICE by not emitting the thunks for the DECL_DEFER_OUTPUT fns just yet but waiting until at_eof time when we return to those. Note, the second testcase ICEs already since r0-110035 with -std=c++0x before it gets a chance to diagnose constexpr virtual method. 2024-11-08 Jakub Jelinek <ja...@redhat.com> PR c++/117317 * semantics.cc (emit_associated_thunks): Do nothing for !DECL_INTERFACE_KNOWN && DECL_DEFER_OUTPUT fns. * g++.dg/cpp2a/pr117317-1.C: New test. * g++.dg/cpp2a/pr117317-2.C: New test.
