On Tue, Jan 18, 2022 at 09:08:03AM -0500, Jason Merrill wrote:
> > 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.
>
> Looks like you added the tf_no_cleanup in r10-3661 (constexpr new). Maybe
> that should only be added if TARGET_EXPR_CLEANUP (t) is null?
I thought about that, but I'm worried that if the cleanup action
is non-empty, then the TREE_CONSTANT (r) = true; after it isn't appropriate,
because the TARGET_EXPR has side-effects.
And the callers like cxx_constant_value_sfinae just return error_mark_node
if it isn't set:
if (sfinae && !TREE_CONSTANT (r))
r = error_mark_node;
Jakub
