tree-ssa-loop-unswitch.c: Include "gimple-iterator.h" and "cfghooks.h"...

tree-ssa-loop-unswitch.c: Include "gimple-iterator.h" and "cfghooks.h"...

gcc/

	* tree-ssa-loop-unswitch.c: Include "gimple-iterator.h" and
	"cfghooks.h", add prototypes for introduced new functions.
	(tree_ssa_unswitch_loops): Use from innermost loop iterator, move all
	checks on ability of loop unswitching to tree_unswitch_single_loop;
	invoke tree_unswitch_single_loop or tree_unswitch_outer_loop depending
	on innermost loop check.
	(tree_unswitch_single_loop): Add all required checks on ability of
	loop unswitching under zero recursive level guard.
	(tree_unswitch_outer_loop): New function.
	(find_loop_guard): Likewise.
	(empty_bb_without_guard_p): Likewise.
	(used_outside_loop_p): Likewise.
	(get_vop_from_header): Likewise.
	(hoist_guard): Likewise.
	(check_exit_phi): Likewise.

gcc/testsuite/

	* gcc.dg/loop-unswitch-2.c: New test.
	* gcc.dg/loop-unswitch-3.c: Likewise.
	* gcc.dg/loop-unswitch-4.c: Likewise.

From-SVN: r228599