2006-11-14  Daniel Berlin  <dberlin@dberlin.org>

	Fix PR tree-optimization/27755

	* tree-ssa-pre.c: Update comments.
	(bb_bitmap_sets): Add pa_in and  deferred member.
	(BB_DEFERRED): New macro.
	(maximal_set): New variable.
	(pre_stats): Add pa_insert member.
	(bitmap_set_and): Short circuit orig == dest.
	(bitmap_set_subtract_values): New function.
	(bitmap_set_contains_expr): Ditto.
	(translate_vuses_through_block): Add phiblock argument.
	(dependent_clean): New function.
	(compute_antic_aux): Update for maximal_set changes.
	(compute_partial_antic_aux): New function.
	(compute_antic): Handle partial anticipation.
	(do_partial_partial_insertion): New function.
	(insert_aux): Handle partial anticipation.
	(add_to_sets): Add to maximal set.
	(compute_avail): Ditto.
	(init_pre): Initialize maximal_set.
	(execute_pre): Do partial anticipation if -O3+.

From-SVN: r118821