https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114970
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:4acdfb71d4fdaa43c2707ad7b2fb7b2b7bddfc42 commit r15-9384-g4acdfb71d4fdaa43c2707ad7b2fb7b2b7bddfc42 Author: Jason Merrill <ja...@redhat.com> Date: Thu Apr 10 18:16:37 2025 -0400 c++: avoid ARM -Wunused-value [PR114970] Because of the __builtin_is_constant_evaluated, maybe_constant_init in expand_default_init fails, so the constexpr constructor isn't folded until cp_fold, which then calls cp_build_init_expr_for_ctor, which builds a COMPOUND_EXPR in case the enclosing expression is relying on the ARM behavior of returning 'this'. As in other places, avoid -Wunused-value on artificial COMPOUND_EXPR. PR c++/114970 gcc/cp/ChangeLog: * cp-gimplify.cc (cp_build_init_expr_for_ctor): Suppress warnings on return_this COMPOUND_EXPR. gcc/testsuite/ChangeLog: * g++.dg/opt/is_constant_evaluated4.C: New test.
