tree-vrp.c (compare_values_warnv): Simplify handling of symbolic ranges by calling...

tree-vrp.c (compare_values_warnv): Simplify handling of symbolic ranges by calling get_single_symbol and tidy up.

	* tree-vrp.c (compare_values_warnv): Simplify handling of symbolic
	ranges by calling get_single_symbol and tidy up.  Look more closely
	into NAME + CST1 vs CST2 comparisons if type overflow is undefined.
ada/
	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Signed_Integer_Subtype>:
	Make same-sized subtypes of signed base types signed.
	* gcc-interface/utils.c (make_type_from_size): Adjust to above change.
	(unchecked_convert): Likewise.

From-SVN: r236548