2004-09-24 Ben Elliston <bje@au.ibm.com>

	    Steven Bosscher  <stevenb@suse.de>
	    Andrew Pinski  <pinskia@physics.uc.edu>

	Merge from edge-vector-branch:
	* basic-block.h: Include vec.h, errors.h. Instantiate a VEC(edge).
	(struct edge_def): Remove pred_next, succ_next members.
	(struct basic_block_def): Remove pred, succ members.  Add preds
	and succs members of type VEC(edge).
	(FALLTHRU_EDGE): Redefine using EDGE_SUCC.
	(BRANCH_EDGE): Likewise.
	(EDGE_CRITICAL_P): Redefine using EDGE_COUNT.
	(EDGE_COUNT, EDGE_I, EDGE_PRED, EDGE_SUCC): New.
	(edge_iterator): New.
	(ei_start, ei_last, ei_end_p, ei_one_before_end_p): New.
	(ei_next, ei_prev, ei_edge, ei_safe_edge): Likewise.
	(FOR_EACH_EDGE): New.
	* bb-reorder.c (find_traces): Use FOR_EACH_EDGE and EDGE_* macros
	where applicable.
	(rotate_loop): Likewise.
	(find_traces_1_route): Likewise.
	(bb_to_key): Likewise.
	(connect_traces): Likewise.
	(copy_bb_p): Likewise.
	(find_rarely_executed_basic_blocks_and_crossing_edges): Likewise.
	(add_labels_and_missing_jumps): Likewise.
	(fix_up_fall_thru_edges): Likewise.
	(find_jump_block): Likewise.
	(fix_crossing_conditional_branches): Likewise.
	(fix_crossing_unconditional_branches): Likewise.
	(add_reg_crossing_jump_notes): Likewise.
	* bt-load.c (augment_live_range): Likewise.
	* cfg.c (clear_edges): Likewise.
	(unchecked_make_edge): Likewise.
	(cached_make_edge): Likewise.
	(make_single_succ_edge): Likewise.
	(remove_edge): Likewise.
	(redirect_edge_succ_nodup): Likewise.
	(check_bb_profile): Likewise.
	(dump_flow_info): Likewise.
	(alloc_aux_for_edges): Likewise.
	(clear_aux_for_edges): Likewise.
	(dump_cfg_bb_info): Likewise.
	* cfganal.c (forwarder_block_p): Likewise.
	(can_fallthru): Likewise.
	(could_fall_through): Likewise.
	(mark_dfs_back_edges): Likewise.
	(set_edge_can_fallthru_flag): Likewise.
	(find_unreachable_blocks): Likewise.
	(create_edge_list): Likewise.
	(verify_edge_list): Likewise.
	(add_noreturn_fake_exit_edges): Likewise.
	(connect_infinite_loops_to_exit): Likewise.
	(flow_reverse_top_sort_order_compute): Likewise.
	(flow_depth_first_order_compute): Likewise.
	(flow_preorder_transversal_compute): Likewise.
	(flow_dfs_compute_reverse_execute): Likewise.
	(dfs_enumerate_from): Likewise.
	(compute_dominance_frontiers_1): Likewise.
	* cfgbuild.c (make_edges): Likewise.
	(compute_outgoing_frequencies): Likewise.
	(find_many_sub_basic_blocks): Likewise.
	(find_sub_basic_blocks): Likewise.
	* cfgcleanup.c (try_simplify_condjump): Likewise.
	(thread_jump): Likewise.
	(try_forward_edges): Likewise.
	(merge_blocks_move): Likewise.
	(outgoing_edges_match): Likewise.
	(try_crossjump_to_edge): Likewise.
	(try_crossjump_bb): Likewise.
	(try_optimize_cfg): Likewise.
	(merge_seq_blocks): Likewise.
	* cfgexpand.c (expand_gimple_tailcall): Likewise.
	(expand_gimple_basic_block): Likewise.
	(construct_init_block): Likewise.
	(construct_exit_block): Likewise.
	* cfghooks.c (verify_flow_info): Likewise.
	(dump_bb): Likewise.
	(delete_basic_block): Likewise.
	(split_edge): Likewise.
	(merge_blocks): Likewise.
	(make_forwarder_block): Likewise.
	(tidy_fallthru_edges): Likewise.
	(can_duplicate_block_p): Likewise.
	(duplicate_block): Likewise.
	* cfglayout.c (fixup_reorder_chain): Likewise.
	(fixup_fallthru_exit_predecessor): Likewise.
	(can_copy_bbs_p): Likewise.
	(copy_bbs): Likewise.
	* cfgloop.c (flow_loops_cfg_dump): Likewise.
	(flow_loop_entry_edges_find): Likewise.
	(flow_loop_exit_edges_find): Likewise.
	(flow_loop_nodes_find): Likewise.
	(mark_single_exit_loops): Likewise.
	(flow_loop_pre_header_scan): Likewise.
	(flow_loop_pre_header_find): Likewise.
	(update_latch_info): Likewise.
	(canonicalize_loop_headers): Likewise.
	(flow_loops_find): Likewise.
	(get_loop_body_in_bfs_order): Likewise.
	(get_loop_exit_edges): Likewise.
	(num_loop_branches): Likewise.
	(verify_loop_structure): Likewise.
	(loop_latch_edge): Likewise.
	(loop_preheader_edge): Likewise.
	* cfgloopanal.c (mark_irreducible_loops): Likewise.
	(expected_loop_iterations): Likewise.
	* cfgloopmanip.c (remove_bbs): Likewise.
	(fix_bb_placement): Likewise.
	(fix_irreducible_loops): Likewise.
	(remove_path): Likewise.
	(scale_bbs_frequencies): Likewise.
	(loopify): Likewise.
	(unloop): Likewise.
	(fix_loop_placement): Likewise.
	(loop_delete_branch_edge): Likewise.
	(duplicate_loop_to_header_edge): Likewise.
	(mfb_keep_just): Likewise.
	(create_preheader): Likewise.
	(force_single_succ_latches): Likewise.
	(loop_split_edge_with): Likewise.
	(create_loop_notes): Likewise.
	* cfgrtl.c (rtl_split_block): Likewise.
	(rtl_merge_blocks): Likewise.
	(rtl_can_merge_blocks): Likewise.
	(try_redirect_by_replacing_jump): Likewise.
	(force_nonfallthru_and_redirect): Likewise.
	(rtl_tidy_fallthru_edge): Likewise.
	(commit_one_edge_insertion): Likewise.
	(commit_edge_insertions): Likewise.
	(commit_edge_insertions_watch_calls): Likewise.
	(rtl_verify_flow_info_1): Likewise.
	(rtl_verify_flow_info): Likewise.
	(purge_dead_edges): Likewise.
	(cfg_layout_redirect_edge_and_branch): Likewise.
	(cfg_layout_can_merge_blocks_p): Likewise.
	(rtl_flow_call_edges_add): Likewise.
	* cse.c (cse_cc_succs): Likewise.
	* df.c (hybrid_search): Likewise.
	* dominance.c (calc_dfs_tree_nonrec): Likewise.
	(calc_dfs_tree): Likewise.
	(calc_idoms): Likewise.
	(recount_dominator): Likewise.
	* domwalk.c (walk_dominator_tree): Likewise.
	* except.c (emit_to_new_bb_before): Likewise.
	(connect_post_landing_pads): Likewise.
	(sjlj_emit_function_enter): Likewise.
	(sjlj_emit_function_exit): Likewise.
	(finish_eh_generation): Likewise.
	* final.c (compute_alignments): Likewise.
	* flow.c (calculate_global_regs_live): Likewise.
	(initialize_uninitialized_subregs): Likewise.
	(init_propagate_block_info): Likewise.
	* function.c (thread_prologue_and_epilogue_insns): Likewise.
	* gcse.c (find_implicit_sets): Likewise.
	(bypass_block): Likewise.
	(bypass_conditional_jumps): Likewise.
	(compute_pre_data): Likewise.
	(insert_insn_end_bb): Likewise.
	(insert_store): Likewise.
	(remove_reachable_equiv_notes): Likewise.
	* global.c (global_conflicts): Likewise.
	(calculate_reg_pav): Likewise.
	* graph.c (print_rtl_graph_with_bb): Likewise.
	* ifcvt.c (mark_loop_exit_edges): Likewise.
	(merge_if_block): Likewise.
	(find_if_header): Likewise.
	(block_jumps_and_fallthru_p): Likewise.
	(find_if_block): Likewise.
	(find_cond_trap): Likewise.
	(block_has_only_trap): Likewise.
	(find_if_case1): Likewise.
	(find_if_case_2): Likewise.
	* lambda-code.c (lambda_loopnest_to_gcc_loopnest): Likewise.
	(perfect_nestify): Likewise.
	* lcm.c (compute_antinout_edge): Likewise.
	(compute_laterin): Likewise.
	(compute_available): Likewise.
	(compute_nearerout): Likewise.
	* loop-doloop.c (doloop_modify): Likewise.
	* loop-init.c (loop_optimizer_init): Likewise.
	* loop-invariant.c (find_exits): Likewise.
	* loop-iv.c (simplify_using_initial_values): Likewise.
	(check_simple_exit): Likewise.
	(find_simple_exit): Likewise.
	* loop-unroll.c (peel_loop_completely): Likewise.
	(unroll_loop_constant_iterations): Likewise.
	(unroll_loop_runtime_iterations): Likewise.
	* loop-unswitch.c (may_unswitch_on): Likewise.
	(unswitch_loop): Likewise.
	* modulo-sched.c (generate_prolog_epilog): Likewise.
	(sms_schedule): Likewise.
	* postreload-gcse.c (eliminate_partially_redundant_load):
	Likewise.
	* predict.c (can_predict_insn_p): Likewise.
	(set_even_probabilities): Likewise.
	(combine_predictions_for_bb): Likewise.
	(predict_loops): Likewise.
	(estimate_probability): Likewise.
	(tree_predict_by_opcode): Likewise.
	(tree_estimate_probability): Likewise.
	(last_basic_block_p): Likewise.
	(propagate_freq): Likewise.
	(estimate_loops_at_level): Likewise.
	(estimate_bb_frequencies): Likewise.
	* profile.c (instrument_edges): Likewise.
	(get_exec_counts): Likewise.
	(compute_branch_probabilities): Likewise.
	(branch_prob): Likewise.
	* ra-build.c (live_in): Likewise.
	* ra-rewrite.c (rewrite_program2): Likewise.
	* ra.c (reg_alloc): Likewise.
	* reg-stack.c (reg_to_stack): Likewise.
	(convert_regs_entry): Likewise.
	(compensate_edge): Likewise.
	(convert_regs_1): Likewise,
	(convert_regs_2): Likewise.
	(convert_regs): Likewise.
	* regrename.c (copyprop_hardreg_forward): Likewise.
	* reload1.c (fixup_abnormal_edges): Likewise.
	* sbitmap.c (sbitmap_intersection_of_succs): Likewise.
	(sbitmap_insersection_of_preds): Likewise.
	(sbitmap_union_of_succs): Likewise.
	(sbitmap_union_of_preds): Likewise.
	* sched-ebb.c (compute_jump_reg_dependencies): Likewise.
	(fix_basic_block_boundaries): Likewise.
	(sched_ebbs): Likewise.
	* sched-rgn.c (build_control_flow): Likewise.
	(find_rgns): Likewise.
	* tracer.c (find_best_successor): Likewise.
	(find_best_predecessor): Likewise.
	(tail_duplicate): Likewise.
	* tree-cfg.c (make_edges): Likewise.
	(make_ctrl_stmt_edges): Likewise.
	(make_goto_expr_edges): Likewise.
	(tree_can_merge_blocks_p): Likewise.
	(tree_merge_blocks): Likewise.
	(cfg_remove_useless_stmts_bb): Likewise.
	(remove_phi_nodes_and_edges_for_unreachable_block): Likewise.
	(tree_block_forwards_to): Likewise.
	(cleanup_control_expr_graph): Likewise.
	(find_taken_edge): Likewise.
	(dump_cfg_stats): Likewise.
	(tree_cfg2vcg): Likewise.
	(disband_implicit_edges): Likewise.
	(tree_find_edge_insert_loc): Likewise.
	(bsi_commit_edge_inserts): Likewise.
	(tree_split_edge): Likewise.
	(tree_verify_flow_info): Likewise.
	(tree_make_forwarder_block): Likewise.
	(tree_forwarder_block_p): Likewise.
	(thread_jumps): Likewise.
	(tree_try_redirect_by_replacing_jump): Likewise.
	(tree_split_block): Likewise.
	(add_phi_args_after_copy_bb): Likewise.
	(rewrite_to_new_ssa_names_bb): Likewise.
	(dump_function_to_file): Likewise.
	(print_pred_bbs): Likewise.
	(print_loop): Likewise.
	(tree_flow_call_edges_add): Likewise.
	(split_critical_edges): Likewise.
	(execute_warn_function_return): Likewise.
	(extract_true_false_edges_from_block): Likewise.
	* tree-if-conv.c (tree_if_conversion): Likewise.
	(if_convertable_bb_p): Likewise.
	(find_phi_replacement_condition): Likewise.
	(combine_blocks): Likewise.
	* tree-into-ssa.c (compute_global_livein): Likewise.
	(ssa_mark_phi_uses): Likewise.
	(ssa_rewrite_initialize_block): Likewise.
	(rewrite_add_phi_arguments): Likewise.
	(ssa_rewrite_phi_arguments): Likewise.
	(insert_phi_nodes_for): Likewise.
	(rewrite_into_ssa): Likewise.
	(rewrite_ssa_into_ssa): Likewise.
	* tree-mudflap.c (mf_build_check_statement_for): Likewise.
	* tree-outof-ssa.c (coalesce_abnormal_edges): Likewise.
	(rewrite_trees): Likewise.
	* tree-pretty-print.c (dump_bb_header): Likewise.
	(dump_implicit_edges): Likewise.
	* tree-sra.c (insert_edge_copies): Likewise.
	(find_obviously_necessary_stmts): Likewise.
	(remove_data_stmt): Likewise.
	* tree-ssa-dom.c (thread_across_edge): Likewise.
	(dom_opt_finalize_block): Likewise.
	(single_incoming_edge_ignoring_loop_edges): Likewise.
	(record_equivalences_from_incoming_edges): Likewise.
	(cprop_into_successor_phis): Likewise.
	* tree-ssa-live.c (live_worklist): Likewise.
	(calculate_live_on_entry): Likewise.
	(calculate_live_on_exit): Likewise.
	* tree-ssa-loop-ch.c (should_duplicate_loop_header_p): Likewise.
	(copy_loop_headers): Likewise.
	* tree-ssa-loop-im.c (loop_commit_inserts): Likewise.
	(fill_always_executed_in): Likewise.
	* tree-ssa-loop-ivcanon.c (create_canonical_iv): Likewise.
	* tree-ssa-loop-ivopts.c (find_interesting_uses): Likewise.
	(compute_phi_arg_on_exit): Likewise.
	* tree-ssa-loop-manip.c (add_exit_phis_edge): Likewise.
	(get_loops_exit): Likewise.
	(split_loop_exit_edge): Likewise.
	(ip_normal_pos): Likewise.
	* tree-ssa-loop-niter.c (simplify_using_initial_conditions):
	Likewise.
	* tree-ssa-phiopt.c (candidate_bb_for_phi_optimization): Likewise.
	(replace_phi_with_stmt): Likewise.
	(value_replacement): Likewise.
	* tree-ssa-pre.c (compute_antic_aux): Likewise.
	(insert_aux): Likewise.
	(init_pre): Likewise.
	* tree-ssa-propagate.c (simulate_stmt): Likewise.
	(simulate_block): Likewise.
	(ssa_prop_init): Likewise.
	* tree-ssa-threadupdate.c (thread_block): Likewise.
	(create_block_for_threading): Likewise.
	(remove_last_stmt_and_useless_edges): Likewise.
	* tree-ssa.c (verify_phi_args): Likewise.
	(verify_ssa): Likewise.
	* tree_tailcall.c (independent_of_stmt_p): Likewise.
	(find_tail_calls): Likewise.
	(eliminate_tail_call): Likewise.
	(tree_optimize_tail_calls_1): Likewise.
	* tree-vectorizer.c (vect_transform_loop): Likewise.
	* var-tracking.c (prologue_stack_adjust): Likewise.
	(vt_stack_adjustments): Likewise.
	(vt_find_locations): Likewise.
	* config/frv/frv.c (frv_ifcvt_modify_tests): Likewise.
	* config/i386/i386.c (ix86_pad_returns): Likewise.
	* config/ia64/ia64.c (ia64_expand_prologue): Likewise.
	* config/rs6000/rs6000.c (rs6000_emit_prologue): Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@88222 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 87 insertions, 82 deletions

diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index 01f5f7d04b6..30aa5c40db3 100644
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -85,7 +85,7 @@ forwarder_block_p (basic_block bb)
   rtx insn;
 
   if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
-      || !bb->succ || bb->succ->succ_next)
+      || EDGE_COUNT (bb->succs) != 1)
     return false;
 
   for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
@@ -105,15 +105,16 @@ can_fallthru (basic_block src, basic_block target)
   rtx insn = BB_END (src);
   rtx insn2;
   edge e;
+  edge_iterator ei;
 
   if (target == EXIT_BLOCK_PTR)
     return true;
   if (src->next_bb != target)
     return 0;
-  for (e = src->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, src->succs)
     if (e->dest == EXIT_BLOCK_PTR
 	&& e->flags & EDGE_FALLTHRU)
-    return 0;
+      return 0;
 
   insn2 = BB_HEAD (target);
   if (insn2 && !active_insn_p (insn2))
@@ -130,13 +131,14 @@ bool
 could_fall_through (basic_block src, basic_block target)
 {
   edge e;
+  edge_iterator ei;
 
   if (target == EXIT_BLOCK_PTR)
     return true;
-  for (e = src->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, src->succs)
     if (e->dest == EXIT_BLOCK_PTR
 	&& e->flags & EDGE_FALLTHRU)
-    return 0;
+      return 0;
   return true;
 }
 
@@ -153,7 +155,7 @@ could_fall_through (basic_block src, basic_block target)
 bool
 mark_dfs_back_edges (void)
 {
-  edge *stack;
+  edge_iterator *stack;
   int *pre;
   int *post;
   int sp;
@@ -167,7 +169,7 @@ mark_dfs_back_edges (void)
   post = xcalloc (last_basic_block, sizeof (int));
 
   /* Allocate stack for back-tracking up CFG.  */
-  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
+  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge_iterator));
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
@@ -177,19 +179,19 @@ mark_dfs_back_edges (void)
   sbitmap_zero (visited);
 
   /* Push the first edge on to the stack.  */
-  stack[sp++] = ENTRY_BLOCK_PTR->succ;
+  stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs);
 
   while (sp)
     {
-      edge e;
+      edge_iterator ei;
       basic_block src;
       basic_block dest;
 
       /* Look at the edge on the top of the stack.  */
-      e = stack[sp - 1];
-      src = e->src;
-      dest = e->dest;
-      e->flags &= ~EDGE_DFS_BACK;
+      ei = stack[sp - 1];
+      src = ei_edge (ei)->src;
+      dest = ei_edge (ei)->dest;
+      ei_edge (ei)->flags &= ~EDGE_DFS_BACK;
 
       /* Check if the edge destination has been visited yet.  */
       if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
@@ -198,11 +200,11 @@ mark_dfs_back_edges (void)
 	  SET_BIT (visited, dest->index);
 
 	  pre[dest->index] = prenum++;
-	  if (dest->succ)
+	  if (EDGE_COUNT (dest->succs) > 0)
 	    {
 	      /* Since the DEST node has been visited for the first
 		 time, check its successors.  */
-	      stack[sp++] = dest->succ;
+	      stack[sp++] = ei_start (dest->succs);
 	    }
 	  else
 	    post[dest->index] = postnum++;
@@ -212,13 +214,13 @@ mark_dfs_back_edges (void)
 	  if (dest != EXIT_BLOCK_PTR && src != ENTRY_BLOCK_PTR
 	      && pre[src->index] >= pre[dest->index]
 	      && post[dest->index] == 0)
-	    e->flags |= EDGE_DFS_BACK, found = true;
+	    ei_edge (ei)->flags |= EDGE_DFS_BACK, found = true;
 
-	  if (! e->succ_next && src != ENTRY_BLOCK_PTR)
+	  if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR)
 	    post[src->index] = postnum++;
 
-	  if (e->succ_next)
-	    stack[sp - 1] = e->succ_next;
+	  if (!ei_one_before_end_p (ei))
+	    ei_next (&stack[sp - 1]);
 	  else
 	    sp--;
 	}
@@ -242,8 +244,9 @@ set_edge_can_fallthru_flag (void)
   FOR_EACH_BB (bb)
     {
       edge e;
+      edge_iterator ei;
 
-      for (e = bb->succ; e; e = e->succ_next)
+      FOR_EACH_EDGE (e, ei, bb->succs)
 	{
 	  e->flags &= ~EDGE_CAN_FALLTHRU;
 
@@ -254,15 +257,15 @@ set_edge_can_fallthru_flag (void)
 
       /* If the BB ends with an invertible condjump all (2) edges are
 	 CAN_FALLTHRU edges.  */
-      if (!bb->succ || !bb->succ->succ_next || bb->succ->succ_next->succ_next)
+      if (EDGE_COUNT (bb->succs) != 2)
 	continue;
       if (!any_condjump_p (BB_END (bb)))
 	continue;
       if (!invert_jump (BB_END (bb), JUMP_LABEL (BB_END (bb)), 0))
 	continue;
       invert_jump (BB_END (bb), JUMP_LABEL (BB_END (bb)), 0);
-      bb->succ->flags |= EDGE_CAN_FALLTHRU;
-      bb->succ->succ_next->flags |= EDGE_CAN_FALLTHRU;
+      EDGE_SUCC (bb, 0)->flags |= EDGE_CAN_FALLTHRU;
+      EDGE_SUCC (bb, 1)->flags |= EDGE_CAN_FALLTHRU;
     }
 }
 
@@ -274,6 +277,7 @@ void
 find_unreachable_blocks (void)
 {
   edge e;
+  edge_iterator ei;
   basic_block *tos, *worklist, bb;
 
   tos = worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
@@ -287,7 +291,7 @@ find_unreachable_blocks (void)
      be only one.  It isn't inconceivable that we might one day directly
      support Fortran alternate entry points.  */
 
-  for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
     {
       *tos++ = e->dest;
 
@@ -301,7 +305,7 @@ find_unreachable_blocks (void)
     {
       basic_block b = *--tos;
 
-      for (e = b->succ; e; e = e->succ_next)
+      FOR_EACH_EDGE (e, ei, b->succs)
 	if (!(e->dest->flags & BB_REACHABLE))
 	  {
 	    *tos++ = e->dest;
@@ -333,6 +337,7 @@ create_edge_list (void)
   int num_edges;
   int block_count;
   basic_block bb;
+  edge_iterator ei;
 
   block_count = n_basic_blocks + 2;   /* Include the entry and exit blocks.  */
 
@@ -342,8 +347,7 @@ create_edge_list (void)
      edges on each basic block.  */
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
     {
-      for (e = bb->succ; e; e = e->succ_next)
-	num_edges++;
+      num_edges += EDGE_COUNT (bb->succs);
     }
 
   elist = xmalloc (sizeof (struct edge_list));
@@ -355,7 +359,7 @@ create_edge_list (void)
 
   /* Follow successors of blocks, and register these edges.  */
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
-    for (e = bb->succ; e; e = e->succ_next)
+    FOR_EACH_EDGE (e, ei, bb->succs)
       elist->index_to_edge[num_edges++] = e;
 
   return elist;
@@ -408,10 +412,11 @@ verify_edge_list (FILE *f, struct edge_list *elist)
   int pred, succ, index;
   edge e;
   basic_block bb, p, s;
+  edge_iterator ei;
 
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
     {
-      for (e = bb->succ; e; e = e->succ_next)
+      FOR_EACH_EDGE (e, ei, bb->succs)
 	{
 	  pred = e->src->index;
 	  succ = e->dest->index;
@@ -439,14 +444,14 @@ verify_edge_list (FILE *f, struct edge_list *elist)
       {
 	int found_edge = 0;
 
-	for (e = p->succ; e; e = e->succ_next)
+	FOR_EACH_EDGE (e, ei, p->succs)
 	  if (e->dest == s)
 	    {
 	      found_edge = 1;
 	      break;
 	    }
 
-	for (e = s->pred; e; e = e->pred_next)
+	FOR_EACH_EDGE (e, ei, s->preds)
 	  if (e->src == p)
 	    {
 	      found_edge = 1;
@@ -471,8 +476,9 @@ edge
 find_edge (basic_block pred, basic_block succ)
 {
   edge e;
+  edge_iterator ei;
 
-  for (e = pred->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, pred->succs)
     if (e->dest == succ)
       return e;
 
@@ -537,14 +543,14 @@ static void
 remove_fake_predecessors (basic_block bb)
 {
   edge e;
+  edge_iterator ei;
 
-  for (e = bb->pred; e;)
+  for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
     {
-      edge tmp = e;
-
-      e = e->pred_next;
-      if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
-	remove_edge (tmp);
+      if ((e->flags & EDGE_FAKE) == EDGE_FAKE)
+	remove_edge (e);
+      else
+	ei_next (&ei);
     }
 }
 
@@ -580,7 +586,7 @@ add_noreturn_fake_exit_edges (void)
   basic_block bb;
 
   FOR_EACH_BB (bb)
-    if (bb->succ == NULL)
+    if (EDGE_COUNT (bb->succs) == 0)
       make_single_succ_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
 }
 
@@ -626,13 +632,13 @@ connect_infinite_loops_to_exit (void)
 void
 flow_reverse_top_sort_order_compute (int *rts_order)
 {
-  edge *stack;
+  edge_iterator *stack;
   int sp;
   int postnum = 0;
   sbitmap visited;
 
   /* Allocate stack for back-tracking up CFG.  */
-  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
+  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge_iterator));
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
@@ -642,18 +648,18 @@ flow_reverse_top_sort_order_compute (int *rts_order)
   sbitmap_zero (visited);
 
   /* Push the first edge on to the stack.  */
-  stack[sp++] = ENTRY_BLOCK_PTR->succ;
+  stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs);
 
   while (sp)
     {
-      edge e;
+      edge_iterator ei;
       basic_block src;
       basic_block dest;
 
       /* Look at the edge on the top of the stack.  */
-      e = stack[sp - 1];
-      src = e->src;
-      dest = e->dest;
+      ei = stack[sp - 1];
+      src = ei_edge (ei)->src;
+      dest = ei_edge (ei)->dest;
 
       /* Check if the edge destination has been visited yet.  */
       if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
@@ -661,20 +667,20 @@ flow_reverse_top_sort_order_compute (int *rts_order)
 	  /* Mark that we have visited the destination.  */
 	  SET_BIT (visited, dest->index);
 
-	  if (dest->succ)
+	  if (EDGE_COUNT (dest->succs) > 0)
 	    /* Since the DEST node has been visited for the first
 	       time, check its successors.  */
-	    stack[sp++] = dest->succ;
+	    stack[sp++] = ei_start (dest->succs);
 	  else
 	    rts_order[postnum++] = dest->index;
 	}
       else
 	{
-	  if (! e->succ_next && src != ENTRY_BLOCK_PTR)
+	  if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR)
 	   rts_order[postnum++] = src->index;
 
-	  if (e->succ_next)
-	    stack[sp - 1] = e->succ_next;
+	  if (!ei_one_before_end_p (ei))
+	    ei_next (&stack[sp - 1]);
 	  else
 	    sp--;
 	}
@@ -694,14 +700,14 @@ flow_reverse_top_sort_order_compute (int *rts_order)
 int
 flow_depth_first_order_compute (int *dfs_order, int *rc_order)
 {
-  edge *stack;
+  edge_iterator *stack;
   int sp;
   int dfsnum = 0;
   int rcnum = n_basic_blocks - 1;
   sbitmap visited;
 
   /* Allocate stack for back-tracking up CFG.  */
-  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
+  stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge_iterator));
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
@@ -711,18 +717,18 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order)
   sbitmap_zero (visited);
 
   /* Push the first edge on to the stack.  */
-  stack[sp++] = ENTRY_BLOCK_PTR->succ;
+  stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs);
 
   while (sp)
     {
-      edge e;
+      edge_iterator ei;
       basic_block src;
       basic_block dest;
 
       /* Look at the edge on the top of the stack.  */
-      e = stack[sp - 1];
-      src = e->src;
-      dest = e->dest;
+      ei = stack[sp - 1];
+      src = ei_edge (ei)->src;
+      dest = ei_edge (ei)->dest;
 
       /* Check if the edge destination has been visited yet.  */
       if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
@@ -735,10 +741,10 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order)
 
 	  dfsnum++;
 
-	  if (dest->succ)
+	  if (EDGE_COUNT (dest->succs) > 0)
 	    /* Since the DEST node has been visited for the first
 	       time, check its successors.  */
-	    stack[sp++] = dest->succ;
+	    stack[sp++] = ei_start (dest->succs);
 	  else if (rc_order)
 	    /* There are no successors for the DEST node so assign
 	       its reverse completion number.  */
@@ -746,14 +752,14 @@ flow_depth_first_order_compute (int *dfs_order, int *rc_order)
 	}
       else
 	{
-	  if (! e->succ_next && src != ENTRY_BLOCK_PTR
+	  if (ei_one_before_end_p (ei) && src != ENTRY_BLOCK_PTR
 	      && rc_order)
 	    /* There are no more successors for the SRC node
 	       so assign its reverse completion number.  */
 	    rc_order[rcnum--] = src->index;
 
-	  if (e->succ_next)
-	    stack[sp - 1] = e->succ_next;
+	  if (!ei_one_before_end_p (ei))
+	    ei_next (&stack[sp - 1]);
 	  else
 	    sp--;
 	}
@@ -789,8 +795,7 @@ struct dfst_node
 void
 flow_preorder_transversal_compute (int *pot_order)
 {
-  edge e;
-  edge *stack;
+  edge_iterator *stack, ei;
   int i;
   int max_successors;
   int sp;
@@ -808,10 +813,7 @@ flow_preorder_transversal_compute (int *pot_order)
 
   FOR_EACH_BB (bb)
     {
-      max_successors = 0;
-      for (e = bb->succ; e; e = e->succ_next)
-	max_successors++;
-
+      max_successors = EDGE_COUNT (bb->succs);
       dfst[bb->index].node
 	= (max_successors
 	   ? xcalloc (max_successors, sizeof (struct dfst_node *)) : NULL);
@@ -824,7 +826,7 @@ flow_preorder_transversal_compute (int *pot_order)
   sbitmap_zero (visited);
 
   /* Push the first edge on to the stack.  */
-  stack[sp++] = ENTRY_BLOCK_PTR->succ;
+  stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs);
 
   while (sp)
     {
@@ -832,9 +834,9 @@ flow_preorder_transversal_compute (int *pot_order)
       basic_block dest;
 
       /* Look at the edge on the top of the stack.  */
-      e = stack[sp - 1];
-      src = e->src;
-      dest = e->dest;
+      ei = stack[sp - 1];
+      src = ei_edge (ei)->src;
+      dest = ei_edge (ei)->dest;
 
       /* Check if the edge destination has been visited yet.  */
       if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
@@ -850,14 +852,14 @@ flow_preorder_transversal_compute (int *pot_order)
 	      dfst[dest->index].up = &dfst[src->index];
 	    }
 
-	  if (dest->succ)
+	  if (EDGE_COUNT (dest->succs) > 0)
 	    /* Since the DEST node has been visited for the first
 	       time, check its successors.  */
-	    stack[sp++] = dest->succ;
+	    stack[sp++] = ei_start (dest->succs);
 	}
 
-      else if (e->succ_next)
-	stack[sp - 1] = e->succ_next;
+      else if (! ei_one_before_end_p (ei))
+	ei_next (&stack[sp - 1]);
       else
 	sp--;
     }
@@ -960,13 +962,14 @@ flow_dfs_compute_reverse_execute (depth_first_search_ds data)
 {
   basic_block bb;
   edge e;
+  edge_iterator ei;
 
   while (data->sp > 0)
     {
       bb = data->stack[--data->sp];
 
       /* Perform depth-first search on adjacent vertices.  */
-      for (e = bb->pred; e; e = e->pred_next)
+      FOR_EACH_EDGE (e, ei, bb->preds)
 	if (!TEST_BIT (data->visited_blocks,
 		       e->src->index - (INVALID_BLOCK + 1)))
 	  flow_dfs_compute_reverse_add_bb (data, e->src);
@@ -1007,10 +1010,11 @@ dfs_enumerate_from (basic_block bb, int reverse,
   while (sp)
     {
       edge e;
+      edge_iterator ei;
       lbb = st[--sp];
       if (reverse)
         {
-          for (e = lbb->pred; e; e = e->pred_next)
+	  FOR_EACH_EDGE (e, ei, lbb->preds)
 	    if (!(e->src->flags & BB_VISITED) && predicate (e->src, data))
 	      {
 	        gcc_assert (tv != rslt_max);
@@ -1020,7 +1024,7 @@ dfs_enumerate_from (basic_block bb, int reverse,
         }
       else
         {
-          for (e = lbb->succ; e; e = e->succ_next)
+	  FOR_EACH_EDGE (e, ei, lbb->succs)
 	    if (!(e->dest->flags & BB_VISITED) && predicate (e->dest, data))
 	      {
 	        gcc_assert (tv != rslt_max);
@@ -1056,6 +1060,7 @@ static void
 compute_dominance_frontiers_1 (bitmap *frontiers, basic_block bb, sbitmap done)
 {
   edge e;
+  edge_iterator ei;
   basic_block c;
 
   SET_BIT (done, bb->index);
@@ -1072,7 +1077,7 @@ compute_dominance_frontiers_1 (bitmap *frontiers, basic_block bb, sbitmap done)
     }
       
   /* Find blocks conforming to rule (1) above.  */
-  for (e = bb->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, bb->succs)
     {
       if (e->dest == EXIT_BLOCK_PTR)
 	continue;
@@ -1106,7 +1111,7 @@ compute_dominance_frontiers (bitmap *frontiers)
 
   sbitmap_zero (done);
 
-  compute_dominance_frontiers_1 (frontiers, ENTRY_BLOCK_PTR->succ->dest, done);
+  compute_dominance_frontiers_1 (frontiers, EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest, done);
 
   sbitmap_free (done);