2010-05-06  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/43934
	* tree-ssa-loop-im.c (movement_possibility): Handle PHI nodes.
	(stmt_cost): Likewise.
	(extract_true_false_args_from_phi): New helper.
	(determine_max_movement): For PHI nodes verify we can hoist them
	and compute their cost.
	(determine_invariantness_stmt): Handle PHI nodes.
	(move_computations_stmt): Likewise.  Hoist PHI nodes in
	if-converted form using COND_EXPRs.
	(move_computations): Return TODO_cleanup_cfg if we hoisted PHI
	nodes.
	(tree_ssa_lim): Likewise.
	* tree-flow.h (tree_ssa_lim): Adjust prototype.
	* tree-ssa-loop.c (tree_ssa_loop_im): Return todo.

	* gcc.dg/tree-ssa/ssa-lim-9.c: New testcase.

From-SVN: r159099