https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118355
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
The problem is we no longer fold the CONST_DECL in
{ .type = ZERO }
to
{ .type = 0 }
and then process_init_constructor_array does:
if (next != error_mark_node
&& (initializer_constant_valid_p (next, TREE_TYPE (next))
!= null_pointer_node))
{
/* Use VEC_INIT_EXPR for non-constant initialization of
trailing elements with no explicit initializers. */
picflags |= PICFLAG_VEC_INIT;
because the ctor isn't initializer_constant_valid_p. Then we create a
VEC_INIT_EXPR and say we can't convert the argument.
