https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121159
--- Comment #12 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:f4abe216199930adfa110059c3c8e642c585388b commit r16-2597-gf4abe216199930adfa110059c3c8e642c585388b Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Jul 29 09:49:55 2025 +0200 calls: Allow musttail calls to noreturn [PR121159] In the PR119483 r15-9003 change we've allowed musttail calls to noreturn functions, after all the decision not to normally tail call noreturn functions is not because it is not possible to tail call those, but because it screws up backtraces. As the following testcase shows, we've done that only for functions not declared [[noreturn]]/_Noreturn but later on discovered through IPA as noreturn. Functions explicitly declared [[noreturn]] have (for historical reasons) volatile FUNCTION_TYPE and the FUNCTION_DECLs are volatile as well, so in order to support those we shouldn't complain on ECF_NORETURN (we've stopped doing so for musttail in PR119483) but also shouldn't complain about TYPE_VOLATILE on their FUNCTION_TYPE (something that IPA doesn't change, I think it only sets TREE_THIS_VOLATILE on the FUNCTION_DECL). volatile on function type really means noreturn as well, it has no other meaning. 2025-07-29 Jakub Jelinek <ja...@redhat.com> PR middle-end/121159 * calls.cc (can_implement_as_sibling_call_p): Don't reject declared noreturn functions in musttail calls. * c-c++-common/pr121159.c: New test. * gcc.dg/plugin/must-tail-call-2.c (test_5): Don't expect an error.
