gcc/ChangeLog:

	PR tree-optimization/89350
	* builtins.c (compute_objsize): Also ignore offsets whose upper
	bound is negative.
	* gimple-ssa-warn-restrict.c (builtin_memref): Add new member.
	(builtin_memref::builtin_memref): Initialize new member.
	Allow EXPR to be null.
	(builtin_memref::extend_offset_range): Replace local with a member.
	Avoid assuming pointer offsets are unsigned.
	(builtin_memref::set_base_and_offset): Determine base object
	before computing offset range.
	(builtin_access::builtin_access): Handle memset.
	(builtin_access::generic_overlap): Replace local with a member.
	(builtin_access::strcat_overlap): Same.
	(builtin_access::overlap): Same.
	(maybe_diag_overlap): Same.
	(maybe_diag_access_bounds): Same.
	(wrestrict_dom_walker::check_call): Handle memset.
	(check_bounds_or_overlap): Same.

gcc/testsuite/ChangeLog:

	PR tree-optimization/89350
	* gcc.dg/Wstringop-overflow.c: Xfail overly ambitious tests.
	* gcc.dg/Wstringop-overflow-11.c: New test.
	* gcc.dg/Wstringop-overflow-12.c: New test.
	* gcc.dg/pr89350.c: New test.
	* gcc.dg/pr40340-1.c: Adjust expected warning.
	* gcc.dg/pr40340-2.c: Same.
	* gcc.dg/pr40340-4.c: Same.
	* gcc.dg/pr40340-5.c: Same.

From-SVN: r269867