[Bug c++/112301] [12/13/14 regression] Double destruction of returned object when exiting the scope causes an exception which gets rethrown since r12-6333-gb10e031458d541

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112301

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:ae07265381d934ee97fb1ce8915731158c91babc

commit r14-5086-gae07265381d934ee97fb1ce8915731158c91babc
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.