gcc/ChangeLog:

	PR tree-optimization/83821
	* tree-ssa-strlen.c (maybe_invalidate): Add argument.  Consider
	the length of a string when available.
	(handle_builtin_memset) Add argument.
	(handle_store, strlen_check_and_optimize_call): Same.
	(check_and_optimize_stmt): Same.  Pass it to callees.

gcc/testsuite/ChangeLog:

	PR tree-optimization/83821
	* c-c++-common/Warray-bounds-4.c: Remove XFAIL.
	* gcc.dg/strlenopt-82.c: New test.
	* gcc.dg/strlenopt-83.c: Same.
	* gcc.dg/strlenopt-84.c: Same.
	* gcc.dg/strlenopt-85.c: Same.
	* gcc.dg/strlenopt-86.c: Same.
	* gcc.dg/tree-ssa/calloc-4.c: Same.
	* gcc.dg/tree-ssa/calloc-5.c: Same.

From-SVN: r277080