re PR rtl-optimization/51014 (ICE: in apply_opt_in_copies, at loop-unroll.c:2283 with -O2 -g -funroll-loops)

	PR rtl-optimization/51014
	* loop-unroll.c (apply_opt_in_copies): Ignore label DEBUG_INSNs
	both from bb and orig_bb.

	* g++.dg/opt/pr51014.C: New test.

From-SVN: r181883