* cfgloop.h (update_single_exits_after_duplication): Declare.
	(loopify, split_loop_bb): Declaration changed.
	* cfgloopmanip.c (split_loop_bb): Take void * as an argument instead
	of rtx.
	(loopify): Added redirect_all_edges argument.
	(update_single_exits_after_duplication): Export.
	* loop-unswitch.c (unswitch_loop): Changed due to loopify change.
	* tree-flow.h (tree_duplicate_loop_to_header_edge,
	tree_ssa_loop_version): Declare.
	* tree-ssa-loop-manip.c (copy_phi_node_args, rename_variables,
	set_phi_def_stmts, tree_duplicate_loop_to_header_edge,
	lv_adjust_loop_header_phi, lv_adjust_loop_entry_edge,
	lv_update_pending_stmts, tree_ssa_loop_version): New functions.

	* tree-ssa-loop-unswitch.c: New file.
	* Makefile.in (tree-ssa-loop-unswitch.o): Add.
	* timevar.def (TV_TREE_LOOP_UNSWITCH): New timevar.
	* tree-flow.h (tree_ssa_unswitch_loops): Declare.
	* tree-optimize.c (init_tree_optimization_passes): Add pass_unswitch.
	* tree-pass.h (pass_unswitch): Declare.
	* tree-ssa-loop.c (tree_ssa_loop_unswitch,
	gate_tree_ssa_loop_unswitch, pass_unswitch): New pass.
	* doc/passes.texi: Documen tree level loop unswitching.

	* gcc.dg/tree-ssa/loop-6.c: New test.

From-SVN: r87943