tree-into-ssa.c (insert_phi_nodes): Use bitmap heads for dominance frontiers.

	* tree-into-ssa.c (insert_phi_nodes): Use bitmap heads
	for dominance frontiers.
	(rewrite_into_ssa): Update for bitmap heads in dominance
	frontiers.
	(insert_updated_phi_nodes_for): Likewise.
	(update_ssa): Likewise.
	* cfganal.c (compute_dominance_frontiers_1): Likewise.
	(compute_dominance_frontiers): Likewise.
	(compute_idf): Likewise.
	* df-problems.c (df_md_local_compute): Likewise.

From-SVN: r160327