PR c/87387
        * builtins.c (unterminated_array): Simplify.
	* expr.c (string_constant): Handle SSA_NAME.  Add more exceptions
	where pointer arithmetic is safe.

	* gcc.dg/warn-stpcpy-no-nul.c: Drop unnecessary xfails.
	* gcc.dg/warn-stplen-no-nul.c: Likewise.

From-SVN: r264585