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, 163 insertions, 95 deletions

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 8664f049901..bba68819a80 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -459,6 +459,7 @@ rtl_split_block (basic_block bb, void *insnp)
   basic_block new_bb;
   rtx insn = insnp;
   edge e;
+  edge_iterator ei;
 
   if (!insn)
     {
@@ -482,9 +483,9 @@ rtl_split_block (basic_block bb, void *insnp)
   BB_END (bb) = insn;
 
   /* Redirect the outgoing edges.  */
-  new_bb->succ = bb->succ;
-  bb->succ = NULL;
-  for (e = new_bb->succ; e; e = e->succ_next)
+  new_bb->succs = bb->succs;
+  bb->succs = NULL;
+  FOR_EACH_EDGE (e, ei, new_bb->succs)
     e->src = new_bb;
 
   if (bb->global_live_at_start)
@@ -625,10 +626,12 @@ rtl_can_merge_blocks (basic_block a,basic_block b)
     return false;
 
   /* There must be exactly one edge in between the blocks.  */
-  return (a->succ && !a->succ->succ_next && a->succ->dest == b
-	  && !b->pred->pred_next && a != b
+  return (EDGE_COUNT (a->succs) == 1
+	  && EDGE_SUCC (a, 0)->dest == b
+	  && EDGE_COUNT (b->preds) == 1
+	  && a != b
 	  /* Must be simple edge.  */
-	  && !(a->succ->flags & EDGE_COMPLEX)
+	  && !(EDGE_SUCC (a, 0)->flags & EDGE_COMPLEX)
 	  && a->next_bb == b
 	  && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
 	  /* If the jump insn has side effects,
@@ -668,7 +671,7 @@ try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
   edge tmp;
   rtx set;
   int fallthru = 0;
-
+  edge_iterator ei;
 
   /* If we are partitioning hot/cold basic blocks, we don't want to
      mess up unconditional or indirect jumps that cross between hot
@@ -686,7 +689,7 @@ try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
     return NULL;
 
   /* Verify that all targets will be TARGET.  */
-  for (tmp = src->succ; tmp; tmp = tmp->succ_next)
+  FOR_EACH_EDGE (tmp, ei, src->succs)
     if (tmp->dest != target && tmp != e)
       break;
 
@@ -814,9 +817,10 @@ try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
     }
 
   /* Keep only one edge out and set proper flags.  */
-  while (src->succ->succ_next)
-    remove_edge (src->succ);
-  e = src->succ;
+  while (EDGE_COUNT (src->succs) > 1)
+    remove_edge (e);
+
+  e = EDGE_SUCC (src, 0);
   if (fallthru)
     e->flags = EDGE_FALLTHRU;
   else
@@ -1040,28 +1044,37 @@ force_nonfallthru_and_redirect (edge e, basic_block target)
       if (e->src == ENTRY_BLOCK_PTR)
 	{
 	  /* We can't redirect the entry block.  Create an empty block
-             at the start of the function which we use to add the new
-             jump.  */
-	  edge *pe1;
-	  basic_block bb
-	    = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
-
+	     at the start of the function which we use to add the new
+	     jump.  */
+	  edge tmp;
+	  edge_iterator ei;
+	  bool found = false;
+	  
+	  basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
+	  
 	  /* Change the existing edge's source to be the new block, and add
 	     a new edge from the entry block to the new block.  */
 	  e->src = bb;
-	  for (pe1 = &ENTRY_BLOCK_PTR->succ; *pe1; pe1 = &(*pe1)->succ_next)
-	    if (*pe1 == e)
-	      {
-		*pe1 = e->succ_next;
-		break;
-	      }
-	  e->succ_next = 0;
-	  bb->succ = e;
+	  for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
+	    {
+	      if (tmp == e)
+		{
+		  VEC_ordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
+		  found = true;
+		  break;
+		}
+	      else
+		ei_next (&ei);
+	    }
+	  
+	  gcc_assert (found);
+	  
+	  VEC_safe_insert (edge, bb->succs, 0, e);
 	  make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
 	}
     }
 
-  if (e->src->succ->succ_next || abnormal_edge_flags)
+  if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
     {
       /* Create the new structures.  */
 
@@ -1113,7 +1126,7 @@ force_nonfallthru_and_redirect (edge e, basic_block target)
 	    }
 	  if (JUMP_P (BB_END (jump_block))
 	      && !any_condjump_p (BB_END (jump_block))
-	      && (jump_block->succ->flags & EDGE_CROSSING))
+	      && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
 	    REG_NOTES (BB_END (jump_block)) = gen_rtx_EXPR_LIST 
 	      (REG_CROSSING_JUMP, NULL_RTX, 
 	       REG_NOTES (BB_END (jump_block)));
@@ -1193,6 +1206,12 @@ rtl_tidy_fallthru_edge (edge e)
 {
   rtx q;
   basic_block b = e->src, c = b->next_bb;
+  edge e2;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e2, ei, b->succs)
+    if (e == e2)
+      break;
 
   /* ??? In a late-running flow pass, other folks may have deleted basic
      blocks by nopping out blocks, leaving multiple BARRIERs between here
@@ -1215,7 +1234,7 @@ rtl_tidy_fallthru_edge (edge e)
   if (JUMP_P (q)
       && onlyjump_p (q)
       && (any_uncondjump_p (q)
-	  || (b->succ == e && e->succ_next == NULL)))
+	  || (EDGE_SUCC (b, 0) == e && ei.index == EDGE_COUNT (b->succs) - 1)))
     {
 #ifdef HAVE_cc0
       /* If this was a conditional jump, we need to also delete
@@ -1303,8 +1322,9 @@ rtl_split_edge (edge edge_in)
   if ((edge_in->flags & EDGE_FALLTHRU) == 0)
     {
       edge e;
+      edge_iterator ei;
 
-      for (e = edge_in->dest->pred; e; e = e->pred_next)
+      FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
 	if (e->flags & EDGE_FALLTHRU)
 	  break;
 
@@ -1518,7 +1538,8 @@ commit_one_edge_insertion (edge e, int watch_calls)
 
   /* Special case -- avoid inserting code between call and storing
      its return value.  */
-  if (watch_calls && (e->flags & EDGE_FALLTHRU) && !e->dest->pred->pred_next
+  if (watch_calls && (e->flags & EDGE_FALLTHRU)
+      && EDGE_COUNT (e->dest->preds) == 1
       && e->src != ENTRY_BLOCK_PTR
       && CALL_P (BB_END (e->src)))
     {
@@ -1538,7 +1559,7 @@ commit_one_edge_insertion (edge e, int watch_calls)
     {
       /* Figure out where to put these things.  If the destination has
          one predecessor, insert there.  Except for the exit block.  */
-      if (e->dest->pred->pred_next == NULL && e->dest != EXIT_BLOCK_PTR)
+      if (EDGE_COUNT (e->dest->preds) == 1 && e->dest != EXIT_BLOCK_PTR)
 	{
 	  bb = e->dest;
 
@@ -1564,7 +1585,7 @@ commit_one_edge_insertion (edge e, int watch_calls)
       /* If the source has one successor and the edge is not abnormal,
          insert there.  Except for the entry block.  */
       else if ((e->flags & EDGE_ABNORMAL) == 0
-	       && e->src->succ->succ_next == NULL
+	       && EDGE_COUNT (e->src->succs) == 1
 	       && e->src != ENTRY_BLOCK_PTR)
 	{
 	  bb = e->src;
@@ -1619,7 +1640,7 @@ commit_one_edge_insertion (edge e, int watch_calls)
 	      NOTE_BASIC_BLOCK (new_note) = bb;
 	      if (JUMP_P (BB_END (bb))
 		  && !any_condjump_p (BB_END (bb))
-		  && (bb->succ->flags & EDGE_CROSSING))
+  		  && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING))
 		REG_NOTES (BB_END (bb)) = gen_rtx_EXPR_LIST 
 		  (REG_CROSSING_JUMP, NULL_RTX, REG_NOTES (BB_END (bb)));
 	      if (after == bb_note)
@@ -1645,9 +1666,9 @@ commit_one_edge_insertion (edge e, int watch_calls)
          for the (single) epilogue, which already has a fallthru edge
          to EXIT.  */
 
-      e = bb->succ;
+      e = EDGE_SUCC (bb, 0);
       gcc_assert (e->dest == EXIT_BLOCK_PTR
-		  && !e->succ_next && (e->flags & EDGE_FALLTHRU));
+		  && EDGE_COUNT (bb->succs) == 1 && (e->flags & EDGE_FALLTHRU));
 
       e->flags &= ~EDGE_FALLTHRU;
       emit_barrier_after (last);
@@ -1677,17 +1698,15 @@ commit_edge_insertions (void)
 
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
     {
-      edge e, next;
+      edge e;
+      edge_iterator ei;
 
-      for (e = bb->succ; e; e = next)
-	{
-	  next = e->succ_next;
-	  if (e->insns.r)
-	    {
-	      changed = true;
-	      commit_one_edge_insertion (e, false);
-	    }
-	}
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	if (e->insns.r)
+	  {
+	    changed = true;
+	    commit_one_edge_insertion (e, false);
+	  }
     }
 
   if (!changed)
@@ -1724,17 +1743,15 @@ commit_edge_insertions_watch_calls (void)
 
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
     {
-      edge e, next;
+      edge e;
+      edge_iterator ei;
 
-      for (e = bb->succ; e; e = next)
-	{
-	  next = e->succ_next;
-	  if (e->insns.r)
-	    {
-	      changed = true;
-	      commit_one_edge_insertion (e, true);
-	    }
-	}
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	if (e->insns.r)
+	  {
+	    changed = true;
+	    commit_one_edge_insertion (e, true);
+	  }
     }
 
   if (!changed)
@@ -1963,10 +1980,11 @@ rtl_verify_flow_info_1 (void)
       int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
       edge e, fallthru = NULL;
       rtx note;
+      edge_iterator ei;
 
       if (INSN_P (BB_END (bb))
 	  && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
-	  && bb->succ && bb->succ->succ_next
+	  && EDGE_COUNT (bb->succs) >= 2
 	  && any_condjump_p (BB_END (bb)))
 	{
 	  if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
@@ -1977,7 +1995,7 @@ rtl_verify_flow_info_1 (void)
 	      err = 1;
 	    }
 	}
-      for (e = bb->succ; e; e = e->succ_next)
+      FOR_EACH_EDGE (e, ei, bb->succs)
 	{
 	  if (e->flags & EDGE_FALLTHRU)
 	    {
@@ -2144,7 +2162,9 @@ rtl_verify_flow_info (void)
   FOR_EACH_BB_REVERSE (bb)
     {
       edge e;
-      for (e = bb->succ; e; e = e->succ_next)
+      edge_iterator ei;
+
+      FOR_EACH_EDGE (e, ei, bb->succs)
 	if (e->flags & EDGE_FALLTHRU)
 	  break;
       if (!e)
@@ -2258,9 +2278,11 @@ rtl_verify_flow_info (void)
 bool
 purge_dead_edges (basic_block bb)
 {
-  edge e, next;
+  edge e;
   rtx insn = BB_END (bb), note;
   bool purged = false;
+  bool found;
+  edge_iterator ei;
 
   /* If this instruction cannot trap, remove REG_EH_REGION notes.  */
   if (NONJUMP_INSN_P (insn)
@@ -2275,23 +2297,31 @@ purge_dead_edges (basic_block bb)
     }
 
   /* Cleanup abnormal edges caused by exceptions or non-local gotos.  */
-  for (e = bb->succ; e; e = next)
+  for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
     {
-      next = e->succ_next;
       if (e->flags & EDGE_EH)
 	{
 	  if (can_throw_internal (BB_END (bb)))
-	    continue;
+	    {
+	      ei_next (&ei);
+	      continue;
+	    }
 	}
       else if (e->flags & EDGE_ABNORMAL_CALL)
 	{
 	  if (CALL_P (BB_END (bb))
 	      && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
 		  || INTVAL (XEXP (note, 0)) >= 0))
-	    continue;
+	    {
+	      ei_next (&ei);
+	      continue;
+	    }
 	}
       else
-	continue;
+	{
+	  ei_next (&ei);
+	  continue;
+	}
 
       remove_edge (e);
       bb->flags |= BB_DIRTY;
@@ -2302,6 +2332,7 @@ purge_dead_edges (basic_block bb)
     {
       rtx note;
       edge b,f;
+      edge_iterator ei;
 
       /* We do care only about conditional jumps and simplejumps.  */
       if (!any_condjump_p (insn)
@@ -2320,10 +2351,8 @@ purge_dead_edges (basic_block bb)
 	    remove_note (insn, note);
 	}
 
-      for (e = bb->succ; e; e = next)
+      for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
 	{
-	  next = e->succ_next;
-
 	  /* Avoid abnormal flags to leak from computed jumps turned
 	     into simplejumps.  */
 
@@ -2333,22 +2362,32 @@ purge_dead_edges (basic_block bb)
 	  if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
 	    /* A conditional jump can fall through into the next
 	       block, so we should keep the edge.  */
-	    continue;
+	    {
+	      ei_next (&ei);
+	      continue;
+	    }
 	  else if (e->dest != EXIT_BLOCK_PTR
 		   && BB_HEAD (e->dest) == JUMP_LABEL (insn))
 	    /* If the destination block is the target of the jump,
 	       keep the edge.  */
-	    continue;
+	    {
+	      ei_next (&ei);
+	      continue;
+	    }
 	  else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
 	    /* If the destination block is the exit block, and this
 	       instruction is a return, then keep the edge.  */
-	    continue;
+	    {
+	      ei_next (&ei);
+	      continue;
+	    }
 	  else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
 	    /* Keep the edges that correspond to exceptions thrown by
 	       this instruction and rematerialize the EDGE_ABNORMAL
 	       flag we just cleared above.  */
 	    {
 	      e->flags |= EDGE_ABNORMAL;
+	      ei_next (&ei);
 	      continue;
 	    }
 
@@ -2358,7 +2397,7 @@ purge_dead_edges (basic_block bb)
 	  remove_edge (e);
 	}
 
-      if (!bb->succ || !purged)
+      if (EDGE_COUNT (bb->succs) == 0 || !purged)
 	return purged;
 
       if (dump_file)
@@ -2368,10 +2407,10 @@ purge_dead_edges (basic_block bb)
 	return purged;
 
       /* Redistribute probabilities.  */
-      if (!bb->succ->succ_next)
+      if (EDGE_COUNT (bb->succs) == 1)
 	{
-	  bb->succ->probability = REG_BR_PROB_BASE;
-	  bb->succ->count = bb->count;
+	  EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE;
+	  EDGE_SUCC (bb, 0)->count = bb->count;
 	}
       else
 	{
@@ -2395,8 +2434,8 @@ purge_dead_edges (basic_block bb)
 	 from non-local gotos and the like.  If there were, we shouldn't
 	 have created the sibcall in the first place.  Second, there
 	 should of course never have been a fallthru edge.  */
-      gcc_assert (bb->succ && !bb->succ->succ_next);
-      gcc_assert (bb->succ->flags == (EDGE_SIBCALL | EDGE_ABNORMAL));
+      gcc_assert (EDGE_COUNT (bb->succs) == 1);
+      gcc_assert (EDGE_SUCC (bb, 0)->flags == (EDGE_SIBCALL | EDGE_ABNORMAL));
 
       return 0;
     }
@@ -2406,28 +2445,33 @@ purge_dead_edges (basic_block bb)
      as these are only created by conditional branches.  If we find such an
      edge we know that there used to be a jump here and can then safely
      remove all non-fallthru edges.  */
-  for (e = bb->succ; e && (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU));
-       e = e->succ_next)
-    ;
+  found = false;
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
+      {
+	found = true;
+	break;
+      }
 
-  if (!e)
+  if (!found)
     return purged;
 
-  for (e = bb->succ; e; e = next)
+  for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
     {
-      next = e->succ_next;
       if (!(e->flags & EDGE_FALLTHRU))
 	{
 	  bb->flags |= BB_DIRTY;
 	  remove_edge (e);
 	  purged = true;
 	}
+      else
+	ei_next (&ei);
     }
 
-  gcc_assert (bb->succ && !bb->succ->succ_next);
+  gcc_assert (EDGE_COUNT (bb->succs) == 1);
 
-  bb->succ->probability = REG_BR_PROB_BASE;
-  bb->succ->count = bb->count;
+  EDGE_SUCC (bb, 0)->probability = REG_BR_PROB_BASE;
+  EDGE_SUCC (bb, 0)->count = bb->count;
 
   if (dump_file)
     fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
@@ -2543,10 +2587,28 @@ cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
 	}
       /* In case we are redirecting fallthru edge to the branch edge
          of conditional jump, remove it.  */
-      if (src->succ->succ_next
-	  && !src->succ->succ_next->succ_next)
+      if (EDGE_COUNT (src->succs) == 2)
 	{
-	  edge s = e->succ_next ? e->succ_next : src->succ;
+	  bool found = false;
+	  unsigned ix = 0;
+	  edge tmp, s;
+	  edge_iterator ei;
+
+	  FOR_EACH_EDGE (tmp, ei, src->succs)
+	    if (e == tmp)
+	      {
+		found = true;
+		ix = ei.index;
+		break;
+	      }
+
+	  gcc_assert (found);
+
+	  if (EDGE_COUNT (src->succs) > (ix + 1))
+	    s = EDGE_SUCC (src, ix + 1);
+	  else
+	    s = EDGE_SUCC (src, 0);
+
 	  if (s->dest == dest
 	      && any_condjump_p (BB_END (src))
 	      && onlyjump_p (BB_END (src)))
@@ -2680,10 +2742,12 @@ cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
     return false;
 
   /* There must be exactly one edge in between the blocks.  */
-  return (a->succ && !a->succ->succ_next && a->succ->dest == b
-	  && !b->pred->pred_next && a != b
+  return (EDGE_COUNT (a->succs) == 1
+	  && EDGE_SUCC (a, 0)->dest == b
+	  && EDGE_COUNT (b->preds) == 1
+	  && a != b
 	  /* Must be simple edge.  */
-	  && !(a->succ->flags & EDGE_COMPLEX)
+	  && !(EDGE_SUCC (a, 0)->flags & EDGE_COMPLEX)
 	  && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
 	  /* If the jump insn has side effects,
 	     we can't kill the edge.  */
@@ -2707,7 +2771,7 @@ cfg_layout_merge_blocks (basic_block a, basic_block b)
   /* We should have fallthru edge in a, or we can do dummy redirection to get
      it cleaned up.  */
   if (JUMP_P (BB_END (a)))
-    try_redirect_by_replacing_jump (a->succ, b, true);
+    try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
   gcc_assert (!JUMP_P (BB_END (a)));
 
   /* Possible line number notes should appear in between.  */
@@ -2906,8 +2970,9 @@ rtl_flow_call_edges_add (sbitmap blocks)
       if (need_fake_edge_p (insn))
 	{
 	  edge e;
+	  edge_iterator ei;
 
-	  for (e = bb->succ; e; e = e->succ_next)
+	  FOR_EACH_EDGE (e, ei, bb->succs)
 	    if (e->dest == EXIT_BLOCK_PTR)
 	      {
 		insert_insn_on_edge (gen_rtx_USE (VOIDmode, const0_rtx), e);
@@ -2955,8 +3020,11 @@ rtl_flow_call_edges_add (sbitmap blocks)
 
 #ifdef ENABLE_CHECKING
 	      if (split_at_insn == BB_END (bb))
-		for (e = bb->succ; e; e = e->succ_next)
-		  gcc_assert (e->dest != EXIT_BLOCK_PTR);
+		{
+		  edge_iterator ei;
+		  FOR_EACH_EDGE (e, ei, bb->succs)
+		    gcc_assert (e->dest != EXIT_BLOCK_PTR);
+		}
 #endif
 
 	      /* Note that the following may create a new basic block