PR sanitizer/63697
	* tree-vrp.c (simplify_internal_call_using_ranges): For subcode ==
	MINUS_EXPR, check overflow on vr0.min - vr1.max and vr0.max - vr1.min
	instead of vr0.min - vr1.min and vr0.max - vr1.max.

	* c-c++-common/ubsan/overflow-sub-3.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_9-branch@216966 138bc75d-0d04-0410-961f-82ee72b054a4