* c-semantics.c (genrtl_do_stmt_1): New function split out from...
	(gen_rtl_do_stmt): ... here.  Call genrtl_do_stmt_1.
	(expand_unreachable_stmt): Expand unreachable while statements
	using genrtl_do_stmt_1.

	* gcc.dg/duff-4.c: New test case.

From-SVN: r67224