[Bug c++/94326] g++: error: pack.ii: ‘-fcompare-debug’ failure (length)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94326

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:2eea00c518d5a72d0bdbc810ae675e7ad5fee414

commit r10-7411-g2eea00c518d5a72d0bdbc810ae675e7ad5fee414
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 27 10:04:31 2020 +0100

    c++: Avoid calls in non-evaluated contexts affect whether function can or
can't throw [PR94326]

    The following testcase FAILs -fcompare-debug, because if we emit a
    -Wreturn-local-addr warning, we tsubst decltype in order to print the
    warning and as that function could throw, set_flags_from_callee during that
    sets cp_function_chain->can_throw and later on we don't set TREE_NOTHROW
    on foo.  While with -w or -Wno-return-local-addr, tsubst isn't called
during
    the warning_at, cp_function_chain->can_throw is kept clear and TREE_NOTHROW
    is set on foo.
    It isn't just a matter of the warning though, in
    int foo ();
    int bar () { return sizeof (foo ()); }
    int baz () { return sizeof (int); }
    I don't really see why we should mark only baz as TREE_NOTHROW and not bar
    too, when neither can really throw.

    2020-03-27  Jakub Jelinek  <jakub@redhat.com>

            PR c++/94326
            * call.c (set_flags_from_callee): Don't update
            cp_function_chain->can_throw or current_function_returns_abnormally
            if cp_unevaluated_operand.

            * g++.dg/other/pr94326.C: New test.