2014-09-05  Richard Biener  <rguenther@suse.de>

	* cfgloop.c (mark_loop_for_removal): Record former header
	when ENABLE_CHECKING.
	* cfgloop.h (strut loop): Add former_header member when
	ENABLE_CHECKING.
	* loop-init.c (fix_loop_structure): Sanity check loops
	marked for removal if they re-appeared.

From-SVN: r214957