* gcc-interface/decl.c (cannot_be_superflat_p): New predicate.

	(gnat_to_gnu_entity) <E_Array_Subtype>: Use it to build the expression
	of the upper bound of the index types.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@148966 138bc75d-0d04-0410-961f-82ee72b054a4