PR middle-end/47917
	* builtins.c (fold_builtin_snprintf): New function.
	(fold_builtin_3): Call it for BUILT_IN_SNPRINTF.
	(fold_builtin_4): Likewise.

	* gcc.c-torture/execute/pr47917.c: New test.
	* gcc.dg/pr47917.c: New test.

From-SVN: r170959