PR tree-optimization/88771 - Misleading -Werror=array-bounds error

PR tree-optimization/88771 - Misleading -Werror=array-bounds error

gcc/ChangeLog:

	PR tree-optimization/88771
	* gimple-ssa-warn-restrict.c (pass_wrestrict::gate): Also enable
	when -Wstringop-overflow is set.
	(builtin_memref::builtin_memref): Adjust excessive upper bound
	only when lower bound is not excessive.
	(maybe_diag_overlap): Detect and diagnose excessive bounds via
	-Wstringop-ovefflow.
	(maybe_diag_offset_bounds): Rename...
	(maybe_diag_access_bounds): ...to this.
	(check_bounds_or_overlap): Adjust for name change above.

gcc/testsuite/ChangeLog:

	PR tree-optimization/88771
	* gcc.dg/Wstringop-overflow-8.c: New test.
	* gcc.dg/Wstringop-overflow-9.c: New test.
	* gcc.dg/Warray-bounds-40.c: New test.
	* gcc.dg/builtin-stpncpy.c: Adjust.
	* gcc.dg/builtin-stringop-chk-4.c: Adjust.
	* g++.dg/opt/memcpy1.C: Adjust.

From-SVN: r268775