https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104055

--- Comment #5 from CVS 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:1a5145f1e3adf8b2ba4ad416a5ddef59a1e34d48

commit r12-6705-g1a5145f1e3adf8b2ba4ad416a5ddef59a1e34d48
Author: Jakub Jelinek <ja...@redhat.com>
Date:   Wed Jan 19 00:42:18 2022 +0100

    c++: Fix handling of temporaries with consteval ctors and non-trivial dtors
[PR104055]

    The following testcase is miscompiled.  We see the constructor is
immediate,
    in build_over_call we trigger:
              if (obj_arg && is_dummy_object (obj_arg))
                {
                  call = build_cplus_new (DECL_CONTEXT (fndecl), call,
complain);
                  obj_arg = NULL_TREE;
                }
    which makes call a TARGET_EXPR with the dtor in TARGET_EXPR_CLEANUP,
    but then call cxx_constant_value on it.  In
cxx_eval_outermost_constant_expr
    it triggers the:
          else if (TREE_CODE (t) != CONSTRUCTOR)
            {
              r = get_target_expr_sfinae (r, tf_warning_or_error |
tf_no_cleanup);
              TREE_CONSTANT (r) = true;
            }
    which wraps the CONSTRUCTOR r into a new TARGET_EXPR, but one without
    dtors (I think we need e.g. the TREE_CONSTANT for the callers),
    and finally build_over_call uses that.

    The following patch fixes that by using get_target_expr instead
    of get_target_expr_sfinae + TREE_CONSTANT (r) = true if t is
    a TARGET_EXPR with non-NULL TARGET_EXPR_CLEANUP.

    2022-01-19  Jakub Jelinek  <ja...@redhat.com>

            PR c++/104055
            * constexpr.cc (cxx_eval_outermost_constant_expr): If t is a
            TARGET_EXPR with TARGET_EXPR_CLEANUP, use get_target_expr rather
            than get_target_expr_sfinae with tf_no_cleanup, and don't set
            TREE_CONSTANT.

            * g++.dg/cpp2a/consteval27.C: New test.

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