PR sanitizer/65081
	* ubsan.c (OBJSZ_MAX_OFFSET): Define.
	(ubsan_expand_objsize_ifn): Don't emit run-time check if the offset
	is in range [-16K, -1].  Don't issue run-time error if
	(ptr > ptr + offset).

	* c-c++-common/ubsan/pr65081.c: New test.

From-SVN: r220784