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, 52 insertions, 39 deletions

diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index 970dcbedda6..b3fde683cb9 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -106,6 +106,7 @@ verify_flow_info (void)
     {
       int n_fallthru = 0;
       edge e;
+      edge_iterator ei;
 
       if (bb->count < 0)
 	{
@@ -119,7 +120,7 @@ verify_flow_info (void)
 	         bb->index, bb->frequency);
 	  err = 1;
 	}
-      for (e = bb->succ; e; e = e->succ_next)
+      FOR_EACH_EDGE (e, ei, bb->succs)
 	{
 	  if (last_visited [e->dest->index + 2] == bb)
 	    {
@@ -165,7 +166,7 @@ verify_flow_info (void)
 	  err = 1;
 	}
 
-      for (e = bb->pred; e; e = e->pred_next)
+      FOR_EACH_EDGE (e, ei, bb->preds)
 	{
 	  if (e->dest != bb)
 	    {
@@ -184,11 +185,12 @@ verify_flow_info (void)
   /* Complete edge checksumming for ENTRY and EXIT.  */
   {
     edge e;
+    edge_iterator ei;
 
-    for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
+    FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
       edge_checksum[e->dest->index + 2] += (size_t) e;
 
-    for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next)
+    FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
       edge_checksum[e->dest->index + 2] -= (size_t) e;
   }
 
@@ -221,6 +223,7 @@ void
 dump_bb (basic_block bb, FILE *outf, int indent)
 {
   edge e;
+  edge_iterator ei;
   char *s_indent;
  
   s_indent = alloca ((size_t) indent + 1);
@@ -245,12 +248,12 @@ dump_bb (basic_block bb, FILE *outf, int indent)
   putc ('\n', outf);
 
   fprintf (outf, ";;%s pred:      ", s_indent);
-  for (e = bb->pred; e; e = e->pred_next)
+  FOR_EACH_EDGE (e, ei, bb->preds)
     dump_edge_info (outf, e, 0);
   putc ('\n', outf);
 
   fprintf (outf, ";;%s succ:      ", s_indent);
-  for (e = bb->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, bb->succs)
     dump_edge_info (outf, e, 1);
   putc ('\n', outf);
 
@@ -360,13 +363,13 @@ delete_basic_block (basic_block bb)
 
   /* Remove the edges into and out of this block.  Note that there may
      indeed be edges in, if we are removing an unreachable loop.  */
-  while (bb->pred != NULL)
-    remove_edge (bb->pred);
-  while (bb->succ != NULL)
-    remove_edge (bb->succ);
+  while (EDGE_COUNT (bb->preds) != 0)
+    remove_edge (EDGE_PRED (bb, 0));
+  while (EDGE_COUNT (bb->succs) != 0)
+    remove_edge (EDGE_SUCC (bb, 0));
 
-  bb->pred = NULL;
-  bb->succ = NULL;
+  VEC_truncate (edge, bb->preds, 0);
+  VEC_truncate (edge, bb->succs, 0);
 
   if (dom_computed[CDI_DOMINATORS])
     delete_from_dominance_info (CDI_DOMINATORS, bb);
@@ -393,11 +396,11 @@ split_edge (edge e)
   ret = cfg_hooks->split_edge (e);
   ret->count = count;
   ret->frequency = freq;
-  ret->succ->probability = REG_BR_PROB_BASE;
-  ret->succ->count = count;
+  EDGE_SUCC (ret, 0)->probability = REG_BR_PROB_BASE;
+  EDGE_SUCC (ret, 0)->count = count;
 
   if (dom_computed[CDI_DOMINATORS])
-    set_immediate_dominator (CDI_DOMINATORS, ret, ret->pred->src);
+    set_immediate_dominator (CDI_DOMINATORS, ret, EDGE_PRED (ret, 0)->src);
 
   if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
     {
@@ -410,21 +413,22 @@ split_edge (edge e)
 	 ret, provided that all other predecessors of e->dest are
 	 dominated by e->dest.  */
 
-      if (get_immediate_dominator (CDI_DOMINATORS, ret->succ->dest)
-	  == ret->pred->src)
+      if (get_immediate_dominator (CDI_DOMINATORS, EDGE_SUCC (ret, 0)->dest)
+	  == EDGE_PRED (ret, 0)->src)
 	{
-	  for (f = ret->succ->dest->pred; f; f = f->pred_next)
+	  edge_iterator ei;
+	  FOR_EACH_EDGE (f, ei, EDGE_SUCC (ret, 0)->dest->preds)
 	    {
-	      if (f == ret->succ)
+	      if (f == EDGE_SUCC (ret, 0))
 		continue;
 
 	      if (!dominated_by_p (CDI_DOMINATORS, f->src,
-				   ret->succ->dest))
+				   EDGE_SUCC (ret, 0)->dest))
 		break;
 	    }
 
 	  if (!f)
-	    set_immediate_dominator (CDI_DOMINATORS, ret->succ->dest, ret);
+	    set_immediate_dominator (CDI_DOMINATORS, EDGE_SUCC (ret, 0)->dest, ret);
 	}
     };
 
@@ -500,6 +504,7 @@ void
 merge_blocks (basic_block a, basic_block b)
 {
   edge e;
+  edge_iterator ei;
 
   if (!cfg_hooks->merge_blocks)
     internal_error ("%s does not support merge_blocks.", cfg_hooks->name);
@@ -510,17 +515,18 @@ merge_blocks (basic_block a, basic_block b)
      partway though the merge of blocks for conditional_execution we'll
      be merging a TEST block with THEN and ELSE successors.  Free the
      whole lot of them and hope the caller knows what they're doing.  */
-  while (a->succ)
-    remove_edge (a->succ);
+
+  while (EDGE_COUNT (a->succs) != 0)
+   remove_edge (EDGE_SUCC (a, 0));
 
   /* Adjust the edges out of B for the new owner.  */
-  for (e = b->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, b->succs)
     e->src = a;
-  a->succ = b->succ;
+  a->succs = b->succs;
   a->flags |= b->flags;
 
   /* B hasn't quite yet ceased to exist.  Attempt to prevent mishap.  */
-  b->pred = b->succ = NULL;
+  b->preds = b->succs = NULL;
   a->global_live_at_end = b->global_live_at_end;
 
   if (dom_computed[CDI_DOMINATORS])
@@ -542,7 +548,8 @@ edge
 make_forwarder_block (basic_block bb, bool (*redirect_edge_p) (edge),
 		      void (*new_bb_cbk) (basic_block))
 {
-  edge e, next_e, fallthru;
+  edge e, fallthru;
+  edge_iterator ei;
   basic_block dummy, jump;
 
   if (!cfg_hooks->make_forwarder_block)
@@ -554,11 +561,13 @@ make_forwarder_block (basic_block bb, bool (*redirect_edge_p) (edge),
   bb = fallthru->dest;
 
   /* Redirect back edges we want to keep.  */
-  for (e = dummy->pred; e; e = next_e)
+  for (ei = ei_start (dummy->preds); (e = ei_safe_edge (ei)); )
     {
-      next_e = e->pred_next;
       if (redirect_edge_p (e))
-	continue;
+	{
+	  ei_next (&ei);
+	  continue;
+	}
 
       dummy->frequency -= EDGE_FREQUENCY (e);
       dummy->count -= e->count;
@@ -630,12 +639,14 @@ tidy_fallthru_edges (void)
 	 merge the flags for the duplicate edges.  So we do not want to
 	 check that the edge is not a FALLTHRU edge.  */
 
-      if ((s = b->succ) != NULL
-	  && ! (s->flags & EDGE_COMPLEX)
-	  && s->succ_next == NULL
-	  && s->dest == c
-	  && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
-	tidy_fallthru_edge (s);
+      if (EDGE_COUNT (b->succs) == 1)
+	{
+	  s = EDGE_SUCC (b, 0);
+	  if (! (s->flags & EDGE_COMPLEX)
+	      && s->dest == c
+	      && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
+	    tidy_fallthru_edge (s);
+	}
     }
 }
 
@@ -645,6 +656,7 @@ bool
 can_duplicate_block_p (basic_block bb)
 {
   edge e;
+  edge_iterator ei;
 
   if (!cfg_hooks->can_duplicate_block_p)
     internal_error ("%s does not support can_duplicate_block_p.",
@@ -655,7 +667,7 @@ can_duplicate_block_p (basic_block bb)
 
   /* Duplicating fallthru block to exit would require adding a jump
      and splitting the real last BB.  */
-  for (e = bb->succ; e; e = e->succ_next)
+  FOR_EACH_EDGE (e, ei, bb->succs)
     if (e->dest == EXIT_BLOCK_PTR && e->flags & EDGE_FALLTHRU)
        return false;
 
@@ -671,6 +683,7 @@ duplicate_block (basic_block bb, edge e)
   edge s, n;
   basic_block new_bb;
   gcov_type new_count = e ? e->count : 0;
+  edge_iterator ei;
 
   if (!cfg_hooks->duplicate_block)
     internal_error ("%s does not support duplicate_block.",
@@ -678,7 +691,7 @@ duplicate_block (basic_block bb, edge e)
 
   if (bb->count < new_count)
     new_count = bb->count;
-  gcc_assert (bb->pred);
+  gcc_assert (EDGE_COUNT (bb->preds) > 0);
 #ifdef ENABLE_CHECKING
   gcc_assert (can_duplicate_block_p (bb));
 #endif
@@ -687,7 +700,7 @@ duplicate_block (basic_block bb, edge e)
 
   new_bb->loop_depth = bb->loop_depth;
   new_bb->flags = bb->flags;
-  for (s = bb->succ; s; s = s->succ_next)
+  FOR_EACH_EDGE (s, ei, bb->succs)
     {
       /* Since we are creating edges from a new block to successors
 	 of another block (which therefore are known to be disjoint), there