flow rewrite

[Richard Henderson <rth at cygnus dot com>]

I've completed that flow rewrite I started back in October.  As a
reminder, this was intended to create real basic block structures
and a proper edge list.

It bootstraps with no regressions on Alpha, i686, and Sparc.

There is one bit of nastiness coming from wanting to run flow2 after
the prologue and epilogue insns have been added.  Can someone tell
me why call_used_regs must include fixed_regs?  This loses information
what is otherwise useful.  Especially since the existing definition
could be obtained by (used || fixed).

The problem showed up on x86 with -fpic.  In that case ebx is fixed,
and therefore call_used, and therefore was considered dead by flow2
and its restoration removed.  I hacked around this with EPILOGUE_USES,
but I think the proper solution is to not include fixed in call_used.

The patch can be found at 

  ftp://ftp.cygnus.com/pub/home/rth/d-flow-1.gz

It is abut 41k after compression.  The changelog flows.

Comments?


r~


	Flow rewrite to use basic block structures and edge lists:

	* basic-block.h (x_basic_block_head, x_basic_block_end): Kill.
	(basic_block_computed_jump_target, basic_block_live_at_start): Kill.
	(struct edge_def): New.
	(struct basic_block_def): New.
	(basic_block_info): New.
	(BLOCK_HEAD, BLOCK_END): Update.
	(ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR): New.
	(uid_block_number): Kill.
	(basic_block_for_insn, BLOCK_FOR_INSN): New.
	(BLOCK_NUM): Update.
	* flow.c (uid_block_number): Kill.
	(uid_volatile): Turn into a bitmap.
	(SET_INSN_VOLATILE): New.
	(basic_block_info): New.
	(entry_exit_blocks): New.
	(x_basic_block_head, x_basic_block_end): Kill.
	(basic_block_computed_jump_target, basic_block_live_at_start): Kill.
	(flow_int_list_blocks, basic_block_succ, basic_block_pred): Kill.
	(basic_block_loop_depth): Kill.
	(basic_block_for_insn): New.
	(find_basic_blocks): Split out initial block counting into 
	find_basic_blocks_0.  Call functions split out of find_basic_blocks_1.
	(find_basic_blocks_0): New.
	(find_basic_blocks_1): Split out edge recognition, unreachable
	block deletion.
	(create_basic_block): New.
	(compute_bb_for_insn): New.
	(clear_edges): New.
	(set_block_num): Update for new structures.
	(free_bb_memory): Kill.
	(add_edge, add_edge_to_label): Kill.
	(mark_label_ref): Kill.
	(make_edges): Rewrite to use edge lists.
	(make_edge, make_label_edge): New.
	(mark_critical_edges): New.
	(delete_unreachable_blocks): Rewrite to use edge lists.  
	Split out EH region manipulation into delete_eh_regions.
	Call tidy_fallthru_edge and merge_blocks.
	(delete_eh_regions): New.
	(delete_note_p): New.
	(delete_insn_chain): New.
	(delete_block): Split out code into delete_insn_chain and
	tidy_fallthru_edge.  Update edge lists.
	(expunge_block): New.
	(flow_delete_insn): New.
	(can_delete_label_p): New.
	(merge_blocks_nomove, merge_blocks): New.
	(tidy_fallthru_edge): New.
	(calculate_loop_depth): New.
	(life_analysis): Allocate and free uid_volatile.
	(free_basic_block_vars): Update for new structures.
	(record_volatile_insns): Use SET_INSN_VOLATILE.
	(mark_regs_live_at_end): Always mark stack pointer live.
	If epilogue rtl emitted, mark all call saved regs live.
	(life_analysis_1): Use bb global_live_at_start, global_live_at_end, 
	local_set regsets.  Use bb->aux to store new_live_at_end.  Begin
	life propagation from EXIT_BLOCK rather than last block.  Clear
	regs_ever_live after mark_regs_live_at_end.
	(allocate_for_life_analysis): Update for new structures.
	(propagate_block): Split out loop depth calculation to
	calculate_loop_depth.
	(regno_uninitialized): Use bb->global_live_at_start.
	(regno_clobbered_at_setjmp): Likewise.
	(find_auto_inc): Use BLOCK_FOR_INSN instead of BLOCK_NUM.
	(dump_flow_info): Update for new structures.
	(dump_edge_info): New.
	(print_rtl_with_bb): Update for new structues.
	(compute_preds_succs): Do no work -- convert edge lists.

	* rtl.c (note_insn_name): Add NOTE_INSN_BASIC_BLOCK.
	* rtl.h (rtunion_def): Add bb entry.
	(NOTE_BASIC_BLOCK): New.
	(NOTE_INSN_BASIC_BLOCK): New.

	* varray.h (varray_data_tag): Add bb entry.
	(VARRAY_BB_INIT, VARRAY_BB): New.

	* except.c (expand_rethrow): Delete insns following the call to
	rethrow.  Put the REG_EH_RETHROW on the call.

	* jump.c (returnjump_p, returnjump_p_1): New.

	* expr.h (nonlocal_goto_handler_labels): New declaration.
	* function.c (nonlocal_goto_handler_labels): Define it.
	(push_function_context_to): Save it.
	(pop_function_context_from): Restore it.
	(nonlocal_label_rtx_list): Kill.
	* function.h (struct function): Add storage space for it.
	* stmt.c (expand_nl_handler_label): Return the new label.
	(expand_nl_goto_receivers): Collect a list of them in
	nonlocal_goto_handler_labels.

	* Makefile.in (print-rtl.o): Depend on basic-block.h.
	(flow.o): Depend on tree.h and insn-flags.h.
	(sched.o): Depend on tree.h and expr.h.

	* function.c (thread_prologue_and_epilogue_insns): Do not
	half-heartedly update bb structures.

	* toplev.c: Add flow2 dump as -dw.
	(rest_of_compilation): Run flow2 after
	thread_prologue_and_epilogue_insns.

	* graph.c (draw_edge): Handle class 3.
	(print_rtl_graph_with_bb): Make abnormal edges red class 2, 
	change non-fall-thru but adjacent to green class 3.  Update 
	to use new structures.

	* print-rtl.c (print_rtx): Handle NOTE_INSN_BASIC_BLOCK.

	* reg-stack.c (BLOCK_NUM): Convert to function.  Abort if
	block_number is -1.
	(reg_to_stack): Initialize block_num to -1.

	* combine.c (set_nonzero_bits_and_sign_copies): Update reference
	to basic_block_live_at_start to bb->global_live_at_start.
	(try_combine): Likewise.
	(reg_dead_at_p): Likewise.
	* global.c (global_conflicts): Likewise.
	Handle stack regs on all abnormal edges, not just computed jumps.
	(mark_elimination): Update reference to basic_block_live_at_start.
	(build_insn_chain): Likewise.
	* haifa-sched.c (haifa_edge): Rename from edge for conflict.
	(is_cfg_nonregular): Look at nonlocal_labels instead of
	nonlocal_label_rtx_list.
	(check_live_1): Update reference to basic_block_live_at_start.
	(update_live_1): Likewise.
	(find_pre_sched_live): Likewise.
	(find_post_sched_live): Likewise.
	* local_alloc.c (update_equiv_regs): Likewise.
	(block_alloc): Likewise.
	* reload1.c (reload, reload_combine): Likewise.
	* reorg.c (mark_target_live_regs): Likewise.
	* sched.c (schedule_block): Likewise.

	* regclass.c (regset_release_memory): Don't free
	basic_block_live_at_start.

	* unroll.c (copy_loop_body): Don't duplicate NOTE_INSN_BASIC_BLOCK.

	* i386.h (EPILOGUE_USES): New.