* emit-rtl.c (remove_unncessary_notes): Remove notes for empty
	blocks.
	* final.c (next_block_index): Remove.
	(max_block_depth): Likewise.
	(pending_blocks): Likewise.
	(init_final): Don't initialize them.
	(final_start_function): Don't set next_block_index.  Set up
	BLOCK_NUMBER.
	(final_scan_insn): Use BLOCK_NUMBER, not next_block_index.
	* function.h (number_blocks): New function.
	* function.c (get_block_vector): New function.
	(identify_blocks): Use it.
	(reorder_blocks): Set NOTE_BLOCK.
	(number_blocks): New function.
	* tree.def (BLOCK): Add documentation for TREE_ASM_WRITTEN flag.
	* tree.h (BLOCK_NUMBER): New macro.
	(tree_block): Add block_num field.
	* dbxout.c (next_block_number): Remove.
	(dbxout_init): Don't set it.
	(dbxout_block): Only output blocks that have TREE_ASM_WRITTEN
	set.  Use BLOCK_NUMBER, rather than next_block_num, to determine
	block numbers.
	* toplev.c (rest_of_compilation): Always call
	find_loop_tree_blocks.  Fix indentation.
	* dwarf2out.c (next_block_number): Remove.
	(gen_lexical_block_die): Use BLOCK_NUMBER, not next_block_number,
	to determine block numbers.
	(gen_inlined_subroutine_die): Likewise.
	(gen_block_die): Only output blocks that have TREE_ASM_WRITTEN set.
	(decls_for_scope): Don't increment next_block_number.
	* dwarfout.c (next_block_number): Remove.
	(output_lexical_block_die): Use BLOCK_NUMBER, not next_block_number,
	to determine block numbers.
	(output_inlined_subroutine_die): Likewise.
	(output_block): Only output blocks that have TREE_ASM_WRITTEN set.
	(output_decls_for_scope): Don't increment next_block_number.
	* sdbout.c (next_block_number): Remove.
	(sdbout_block): Use BLOCK_NUMBER.
	(sdbout_begin_block): Simplify.
	* xcoffout.c (next_block_number): Remove.
	(xcoffout_block): Use BLOCK_NUMBER, not next_block_number.
	(xcoffout_begin_block): Don't set next_block_number.
	(xcoffout_begin_function): Likewise. Use BLOCK_NUMBER, not
	next_block_number.

From-SVN: r32228