[Bug c++/33799] Return value's destructor not executed when a local variable's destructor throws

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=33799

--- Comment #25 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:7fae9873a74c7a5a62044bb6a4cde8e3ac1a5e5d

commit r12-9990-g7fae9873a74c7a5a62044bb6a4cde8e3ac1a5e5d
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Oct 30 17:44:54 2023 -0400

    c++: retval dtor on rethrow [PR112301]

    In r12-6333 for PR33799, I fixed the example in [except.ctor]/2.  In that
    testcase, the exception is caught and the function returns again,
    successfully.

    In this testcase, however, the exception is rethrown, and hits two separate
    cleanups: one in the try block and the other in the function body.  So we
    destroy twice an object that was only constructed once.

    Fortunately, the fix for the normal case is easy: we just need to clear the
    "return value constructed by return" flag when we do it the first time.

    This gets more complicated with the named return value optimization, since
    we don't want to destroy the return value while the NRV variable is still
in
    scope.

            PR c++/112301
            PR c++/102191
            PR c++/33799

    gcc/cp/ChangeLog:

            * except.cc (maybe_splice_retval_cleanup): Clear
            current_retval_sentinel when destroying retval.
            * semantics.cc (nrv_data): Add in_nrv_cleanup.
            (finalize_nrv): Set it.
            (finalize_nrv_r): Fix handling of throwing cleanups.

    gcc/testsuite/ChangeLog:

            * g++.dg/eh/return1.C: Add more cases.