tree-dfa.c (get_ref_base_and_extent): Set *pmax_size to -1 if *poffset + *pmax_size overflows in HOST_WIDE_INT.

	* tree-dfa.c (get_ref_base_and_extent): Set *pmax_size to -1
	if *poffset + *pmax_size overflows in HOST_WIDE_INT.
	Set *poffset to 0 and *psize and *pmax_size to -1 if
	*poffset + *psize overflows in HOST_WIDE_INT.

	* gcc.dg/pr82389.c: New test.

From-SVN: r253357