* builtins.h (c_srlen): Add argument.
	* builtins.c (warn_string_no_nul): New function.
	(c_strlen): Add argument and use it.  Update recursive calls.
	Pass DECL argument to string_constant to get info on non
	terminated strings.  Update *NONSTR as needed.
	(fold_builtin_strlen): Add argument to calls to c_strlen.
	Warn for unterminated arrays.
	(warn_string_no_null): Add prototype.
	* expr.c (string_constant): Update arguments.  Update recursive
	calls appropriately.  Detect missing NUL terminator and outermost
	declaration its missing in.
	Improve checks for arrays with nonzero lower bound or elements
	that are not a single byte.  Simplify offset computation.
	Simplify checks for non-NUL terminated strings.
	* gimple-fold.c (get_range_strlen): Add argument to c_strlen call.
	* gimple-ssa-sprintf.c (get_string_length): Remove unnecessary code.

	* gcc.dg/warn-strlen-no-nul.c: New test.

Co-Authored-By: Bernd Edlinger <bernd.edlinger@hotmail.de>
Co-Authored-By: Jeff Law <law@redhat.com>

From-SVN: r264302