https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53932
--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:04cf6b57c7c467f615a16b7bbda574671e3fb2df commit r10-11356-g04cf6b57c7c467f615a16b7bbda574671e3fb2df Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Jan 19 23:27:34 2023 +0100 c++: Fix up handling of references to anon union members in initializers [PR53932] For anonymous union members we create artificial VAR_DECLs which have DECL_VALUE_EXPR for the actual COMPONENT_REF. That works just fine inside of functions (including global dynamic constructors), because during gimplification such VAR_DECLs are gimplified as their DECL_VALUE_EXPR. This is also done during regimplification. But references to these artificial vars in DECL_INITIAL expressions aren't ever replaced by the DECL_VALUE_EXPRs, so we end up either with link failures like on the testcase below, or worse ICEs with LTO. The following patch fixes those during cp_fully_fold_init where we already walk all the trees (!data->genericize means that function rather than cp_fold_function). 2023-01-19 Jakub Jelinek <ja...@redhat.com> PR c++/53932 * cp-gimplify.c (cp_fold_r): During cp_fully_fold_init replace DECL_ANON_UNION_VAR_P VAR_DECLs with their corresponding DECL_VALUE_EXPR. * g++.dg/init/pr53932.C: New test. (cherry picked from commit 9b9a989adc042b304572fd6d4ade46b47be6ccb8)
