use auto_sbitmap in various places

gcc/ChangeLog:

2016-07-26  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	* bt-load.c (compute_out): Use auto_sbitmap class.
	(link_btr_uses): Likewise.
	* cfganal.c (mark_dfs_back_edges): Likewise.
	(post_order_compute): Likewise.
	(inverted_post_order_compute): Likewise.
	(pre_and_rev_post_order_compute_fn): Likewise.
	(single_pred_before_succ_order): Likewise.
	* cfgexpand.c (pass_expand::execute): Likewise.
	* cfgloop.c (verify_loop_structure): Likewise.
	* cfgloopmanip.c (fix_bb_placements): Likewise.
	(remove_path): Likewise.
	(update_dominators_in_loop): Likewise.
	* cfgrtl.c (break_superblocks): Likewise.
	* ddg.c (check_sccs): Likewise.
	(create_ddg_all_sccs): Likewise.
	* df-core.c (df_worklist_dataflow): Likewise.
	* dse.c (dse_step3): Likewise.
	* except.c (eh_region_outermost): Likewise.
	* function.c (thread_prologue_and_epilogue_insns): Likewise.
	* gcse.c (prune_expressions): Likewise.
	(prune_insertions_deletions): Likewise.
	* gimple-ssa-backprop.c (backprop::~backprop): Likewise.
	* graph.c (draw_cfg_nodes_no_loops): Likewise.
	* ira-lives.c (remove_some_program_points_and_update_live_ranges): Likewise.
	* lcm.c (compute_earliest): Likewise.
	(compute_farthest): Likewise.
	* loop-unroll.c (unroll_loop_constant_iterations): Likewise.
	(unroll_loop_runtime_iterations): Likewise.
	(unroll_loop_stupid): Likewise.
	* lower-subreg.c (decompose_multiword_subregs): Likewise.
	* lra-lives.c: Likewise.
	* lra.c (lra): Likewise.
	* modulo-sched.c (schedule_reg_moves): Likewise.
	(optimize_sc): Likewise.
	(get_sched_window): Likewise.
	(sms_schedule_by_order): Likewise.
	(check_nodes_order): Likewise.
	(order_nodes_of_sccs): Likewise.
	(order_nodes_in_scc): Likewise.
	* recog.c (split_all_insns): Likewise.
	* regcprop.c (pass_cprop_hardreg::execute): Likewise.
	* reload1.c (reload): Likewise.
	* sched-rgn.c (haifa_find_rgns): Likewise.
	(split_edges): Likewise.
	(compute_trg_info): Likewise.
	* sel-sched.c (init_seqno): Likewise.
	* store-motion.c (remove_reachable_equiv_notes): Likewise.
	* tree-into-ssa.c (update_ssa): Likewise.
	* tree-ssa-live.c (live_worklist): Likewise.
	* tree-ssa-loop-im.c (fill_always_executed_in): Likewise.
	* tree-ssa-loop-ivcanon.c (try_unroll_loop_completely):
	* Likewise.
	(try_peel_loop): Likewise.
	* tree-ssa-loop-manip.c (tree_transform_and_unroll_loop):
	* Likewise.
	* tree-ssa-pre.c (compute_antic): Likewise.
	* tree-ssa-reassoc.c (undistribute_ops_list): Likewise.
	* tree-stdarg.c (reachable_at_most_once): Likewise.
	* tree-vect-slp.c (vect_attempt_slp_rearrange_stmts): Likewise.
	* var-tracking.c (vt_find_locations): Likewise.

From-SVN: r238748

38 files changed, 162 insertions, 269 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 79f79eb..489d9d7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,68 @@
 2016-07-26  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>
 
+	* bt-load.c (compute_out): Use auto_sbitmap class.
+	(link_btr_uses): Likewise.
+	* cfganal.c (mark_dfs_back_edges): Likewise.
+	(post_order_compute): Likewise.
+	(inverted_post_order_compute): Likewise.
+	(pre_and_rev_post_order_compute_fn): Likewise.
+	(single_pred_before_succ_order): Likewise.
+	* cfgexpand.c (pass_expand::execute): Likewise.
+	* cfgloop.c (verify_loop_structure): Likewise.
+	* cfgloopmanip.c (fix_bb_placements): Likewise.
+	(remove_path): Likewise.
+	(update_dominators_in_loop): Likewise.
+	* cfgrtl.c (break_superblocks): Likewise.
+	* ddg.c (check_sccs): Likewise.
+	(create_ddg_all_sccs): Likewise.
+	* df-core.c (df_worklist_dataflow): Likewise.
+	* dse.c (dse_step3): Likewise.
+	* except.c (eh_region_outermost): Likewise.
+	* function.c (thread_prologue_and_epilogue_insns): Likewise.
+	* gcse.c (prune_expressions): Likewise.
+	(prune_insertions_deletions): Likewise.
+	* gimple-ssa-backprop.c (backprop::~backprop): Likewise.
+	* graph.c (draw_cfg_nodes_no_loops): Likewise.
+	* ira-lives.c (remove_some_program_points_and_update_live_ranges): Likewise.
+	* lcm.c (compute_earliest): Likewise.
+	(compute_farthest): Likewise.
+	* loop-unroll.c (unroll_loop_constant_iterations): Likewise.
+	(unroll_loop_runtime_iterations): Likewise.
+	(unroll_loop_stupid): Likewise.
+	* lower-subreg.c (decompose_multiword_subregs): Likewise.
+	* lra-lives.c: Likewise.
+	* lra.c (lra): Likewise.
+	* modulo-sched.c (schedule_reg_moves): Likewise.
+	(optimize_sc): Likewise.
+	(get_sched_window): Likewise.
+	(sms_schedule_by_order): Likewise.
+	(check_nodes_order): Likewise.
+	(order_nodes_of_sccs): Likewise.
+	(order_nodes_in_scc): Likewise.
+	* recog.c (split_all_insns): Likewise.
+	* regcprop.c (pass_cprop_hardreg::execute): Likewise.
+	* reload1.c (reload): Likewise.
+	* sched-rgn.c (haifa_find_rgns): Likewise.
+	(split_edges): Likewise.
+	(compute_trg_info): Likewise.
+	* sel-sched.c (init_seqno): Likewise.
+	* store-motion.c (remove_reachable_equiv_notes): Likewise.
+	* tree-into-ssa.c (update_ssa): Likewise.
+	* tree-ssa-live.c (live_worklist): Likewise.
+	* tree-ssa-loop-im.c (fill_always_executed_in): Likewise.
+	* tree-ssa-loop-ivcanon.c (try_unroll_loop_completely):
+	* Likewise.
+	(try_peel_loop): Likewise.
+	* tree-ssa-loop-manip.c (tree_transform_and_unroll_loop):
+	* Likewise.
+	* tree-ssa-pre.c (compute_antic): Likewise.
+	* tree-ssa-reassoc.c (undistribute_ops_list): Likewise.
+	* tree-stdarg.c (reachable_at_most_once): Likewise.
+	* tree-vect-slp.c (vect_attempt_slp_rearrange_stmts): Likewise.
+	* var-tracking.c (vt_find_locations): Likewise.
+
+2016-07-26  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>
+
 	* sbitmap.h (auto_sbitmap): New class.
 
 2016-07-26  Alan Modra  <amodra@gmail.com>
diff --git a/gcc/bt-load.c b/gcc/bt-load.c
index aa02f64..5b1bcec 100644
--- a/gcc/bt-load.c
+++ b/gcc/bt-load.c
@@ -626,7 +626,7 @@ compute_out (sbitmap *bb_out, sbitmap *bb_gen, sbitmap *bb_kill, int max_uid)
      Iterate until the bb_out sets stop growing.  */
   int i;
   int changed;
-  sbitmap bb_in = sbitmap_alloc (max_uid);
+  auto_sbitmap bb_in (max_uid);
 
   for (i = NUM_FIXED_BLOCKS; i < last_basic_block_for_fn (cfun); i++)
     bitmap_copy (bb_out[i], bb_gen[i]);
@@ -642,7 +642,6 @@ compute_out (sbitmap *bb_out, sbitmap *bb_gen, sbitmap *bb_kill, int max_uid)
 					       bb_in, bb_kill[i]);
 	}
     }
-  sbitmap_free (bb_in);
 }
 
 static void
@@ -650,7 +649,7 @@ link_btr_uses (btr_def **def_array, btr_user **use_array, sbitmap *bb_out,
 	       sbitmap *btr_defset, int max_uid)
 {
   int i;
-  sbitmap reaching_defs = sbitmap_alloc (max_uid);
+  auto_sbitmap reaching_defs (max_uid);
 
   /* Link uses to the uses lists of all of their reaching defs.
      Count up the number of reaching defs of each use.  */
@@ -683,7 +682,7 @@ link_btr_uses (btr_def **def_array, btr_user **use_array, sbitmap *bb_out,
 	      if (user != NULL)
 		{
 		  /* Find all the reaching defs for this use.  */
-		  sbitmap reaching_defs_of_reg = sbitmap_alloc (max_uid);
+		  auto_sbitmap reaching_defs_of_reg (max_uid);
 		  unsigned int uid = 0;
 		  sbitmap_iterator sbi;
 
@@ -738,7 +737,6 @@ link_btr_uses (btr_def **def_array, btr_user **use_array, sbitmap *bb_out,
 		      user->next = def->uses;
 		      def->uses = user;
 		    }
-		  sbitmap_free (reaching_defs_of_reg);
 		}
 
 	      if (CALL_P (insn))
@@ -754,7 +752,6 @@ link_btr_uses (btr_def **def_array, btr_user **use_array, sbitmap *bb_out,
 	    }
 	}
     }
-  sbitmap_free (reaching_defs);
 }
 
 static void
diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index aabc065..931e814 100644
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -67,7 +67,6 @@ mark_dfs_back_edges (void)
   int sp;
   int prenum = 1;
   int postnum = 1;
-  sbitmap visited;
   bool found = false;
 
   /* Allocate the preorder and postorder number arrays.  */
@@ -79,7 +78,7 @@ mark_dfs_back_edges (void)
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
   /* None of the nodes in the CFG have been visited yet.  */
   bitmap_clear (visited);
@@ -138,7 +137,6 @@ mark_dfs_back_edges (void)
   free (pre);
   free (post);
   free (stack);
-  sbitmap_free (visited);
 
   return found;
 }
@@ -642,7 +640,6 @@ post_order_compute (int *post_order, bool include_entry_exit,
   edge_iterator *stack;
   int sp;
   int post_order_num = 0;
-  sbitmap visited;
   int count;
 
   if (include_entry_exit)
@@ -653,7 +650,7 @@ post_order_compute (int *post_order, bool include_entry_exit,
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
   /* None of the nodes in the CFG have been visited yet.  */
   bitmap_clear (visited);
@@ -726,7 +723,6 @@ post_order_compute (int *post_order, bool include_entry_exit,
     }
 
   free (stack);
-  sbitmap_free (visited);
   return post_order_num;
 }
 
@@ -820,7 +816,6 @@ inverted_post_order_compute (int *post_order,
   edge_iterator *stack;
   int sp;
   int post_order_num = 0;
-  sbitmap visited;
 
   if (flag_checking)
     verify_no_unreachable_blocks ();
@@ -830,7 +825,7 @@ inverted_post_order_compute (int *post_order,
   sp = 0;
 
   /* Allocate bitmap to track nodes that have been visited.  */
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
   /* None of the nodes in the CFG have been visited yet.  */
   bitmap_clear (visited);
@@ -956,7 +951,6 @@ inverted_post_order_compute (int *post_order,
   post_order[post_order_num++] = EXIT_BLOCK;
 
   free (stack);
-  sbitmap_free (visited);
   return post_order_num;
 }
 
@@ -981,7 +975,6 @@ pre_and_rev_post_order_compute_fn (struct function *fn,
   int sp;
   int pre_order_num = 0;
   int rev_post_order_num = n_basic_blocks_for_fn (cfun) - 1;
-  sbitmap visited;
 
   /* Allocate stack for back-tracking up CFG.  */
   stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1);
@@ -999,7 +992,7 @@ pre_and_rev_post_order_compute_fn (struct function *fn,
     rev_post_order_num -= NUM_FIXED_BLOCKS;
 
   /* Allocate bitmap to track nodes that have been visited.  */
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
   /* None of the nodes in the CFG have been visited yet.  */
   bitmap_clear (visited);
@@ -1056,7 +1049,6 @@ pre_and_rev_post_order_compute_fn (struct function *fn,
     }
 
   free (stack);
-  sbitmap_free (visited);
 
   if (include_entry_exit)
     {
@@ -1569,7 +1561,7 @@ single_pred_before_succ_order (void)
   basic_block *order = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
   unsigned n = n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS;
   unsigned np, i;
-  sbitmap visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
 #define MARK_VISITED(BB) (bitmap_set_bit (visited, (BB)->index))
 #define VISITED_P(BB) (bitmap_bit_p (visited, (BB)->index))
@@ -1603,7 +1595,6 @@ single_pred_before_succ_order (void)
       n -= np;
     }
 
-  sbitmap_free (visited);
   gcc_assert (n == 0);
   return order;
 
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 9a2837b..417f0dc 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -6159,7 +6159,6 @@ unsigned int
 pass_expand::execute (function *fun)
 {
   basic_block bb, init_block;
-  sbitmap blocks;
   edge_iterator ei;
   edge e;
   rtx_insn *var_seq, *var_ret_seq;
@@ -6472,10 +6471,9 @@ pass_expand::execute (function *fun)
 	}
     }
 
-  blocks = sbitmap_alloc (last_basic_block_for_fn (fun));
+  auto_sbitmap blocks (last_basic_block_for_fn (fun));
   bitmap_ones (blocks);
   find_many_sub_basic_blocks (blocks);
-  sbitmap_free (blocks);
   purge_all_dead_edges ();
 
   expand_stack_alignment ();
diff --git a/gcc/cfgloop.c b/gcc/cfgloop.c
index 2087b90..8f531b0 100644
--- a/gcc/cfgloop.c
+++ b/gcc/cfgloop.c
@@ -1312,7 +1312,6 @@ DEBUG_FUNCTION void
 verify_loop_structure (void)
 {
   unsigned *sizes, i, j;
-  sbitmap irreds;
   basic_block bb, *bbs;
   struct loop *loop;
   int err = 0;
@@ -1320,7 +1319,6 @@ verify_loop_structure (void)
   unsigned num = number_of_loops (cfun);
   struct loop_exit *exit, *mexit;
   bool dom_available = dom_info_available_p (CDI_DOMINATORS);
-  sbitmap visited;
 
   if (loops_state_satisfies_p (LOOPS_NEED_FIXUP))
     {
@@ -1366,7 +1364,7 @@ verify_loop_structure (void)
       }
 
   /* Check the recorded loop father and sizes of loops.  */
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
   bitmap_clear (visited);
   bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
   FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
@@ -1413,7 +1411,6 @@ verify_loop_structure (void)
 	}
     }
   free (bbs);
-  sbitmap_free (visited);
 
   /* Check headers and latches.  */
   FOR_EACH_LOOP (loop, 0)
@@ -1480,7 +1477,7 @@ verify_loop_structure (void)
   if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
     {
       /* Record old info.  */
-      irreds = sbitmap_alloc (last_basic_block_for_fn (cfun));
+      auto_sbitmap irreds (last_basic_block_for_fn (cfun));
       FOR_EACH_BB_FN (bb, cfun)
 	{
 	  edge_iterator ei;
@@ -1532,7 +1529,6 @@ verify_loop_structure (void)
 	      e->flags &= ~(EDGE_ALL_FLAGS + 1);
 	    }
 	}
-      free (irreds);
     }
 
   /* Check the recorded loop exits.  */
diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c
index 707a130..6bd2d85 100644
--- a/gcc/cfgloopmanip.c
+++ b/gcc/cfgloopmanip.c
@@ -181,7 +181,6 @@ fix_bb_placements (basic_block from,
 		   bool *irred_invalidated,
 		   bitmap loop_closed_ssa_invalidated)
 {
-  sbitmap in_queue;
   basic_block *queue, *qtop, *qbeg, *qend;
   struct loop *base_loop, *target_loop;
   edge e;
@@ -201,7 +200,7 @@ fix_bb_placements (basic_block from,
       || from == base_loop->header)
     return;
 
-  in_queue = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap in_queue (last_basic_block_for_fn (cfun));
   bitmap_clear (in_queue);
   bitmap_set_bit (in_queue, from->index);
   /* Prevent us from going out of the base_loop.  */
@@ -292,7 +291,6 @@ fix_bb_placements (basic_block from,
 	  bitmap_set_bit (in_queue, pred->index);
 	}
     }
-  free (in_queue);
   free (queue);
 }
 
@@ -306,7 +304,6 @@ remove_path (edge e)
   basic_block *rem_bbs, *bord_bbs, from, bb;
   vec<basic_block> dom_bbs;
   int i, nrem, n_bord_bbs;
-  sbitmap seen;
   bool irred_invalidated = false;
   edge_iterator ei;
   struct loop *l, *f;
@@ -345,7 +342,7 @@ remove_path (edge e)
 
   n_bord_bbs = 0;
   bord_bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
-  seen = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap seen (last_basic_block_for_fn (cfun));
   bitmap_clear (seen);
 
   /* Find "border" hexes -- i.e. those with predecessor in removed path.  */
@@ -407,8 +404,6 @@ remove_path (edge e)
 	  dom_bbs.safe_push (ldom);
     }
 
-  free (seen);
-
   /* Recount dominators.  */
   iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, true);
   dom_bbs.release ();
@@ -616,11 +611,10 @@ static void
 update_dominators_in_loop (struct loop *loop)
 {
   vec<basic_block> dom_bbs = vNULL;
-  sbitmap seen;
   basic_block *body;
   unsigned i;
 
-  seen = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap seen (last_basic_block_for_fn (cfun));
   bitmap_clear (seen);
   body = get_loop_body (loop);
 
@@ -643,7 +637,6 @@ update_dominators_in_loop (struct loop *loop)
 
   iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, false);
   free (body);
-  free (seen);
   dom_bbs.release ();
 }
 
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index e1f354e..0d335fc 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -4272,11 +4272,10 @@ cfg_layout_initialize (unsigned int flags)
 void
 break_superblocks (void)
 {
-  sbitmap superblocks;
   bool need = false;
   basic_block bb;
 
-  superblocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap superblocks (last_basic_block_for_fn (cfun));
   bitmap_clear (superblocks);
 
   FOR_EACH_BB_FN (bb, cfun)
@@ -4292,8 +4291,6 @@ break_superblocks (void)
       rebuild_jump_labels (get_insns ());
       find_many_sub_basic_blocks (superblocks);
     }
-
-  free (superblocks);
 }
 
 /* Finalize the changes: reorder insn list according to the sequence specified
diff --git a/gcc/ddg.c b/gcc/ddg.c
index 101fc72..72cf1cf 100644
--- a/gcc/ddg.c
+++ b/gcc/ddg.c
@@ -997,7 +997,7 @@ static void
 check_sccs (ddg_all_sccs_ptr sccs, int num_nodes)
 {
   int i = 0;
-  sbitmap tmp = sbitmap_alloc (num_nodes);
+  auto_sbitmap tmp (num_nodes);
 
   bitmap_clear (tmp);
   for (i = 0; i < sccs->num_sccs; i++)
@@ -1008,7 +1008,6 @@ check_sccs (ddg_all_sccs_ptr sccs, int num_nodes)
       gcc_assert (!bitmap_intersect_p (tmp, sccs->sccs[i]->nodes));
       bitmap_ior (tmp, tmp, sccs->sccs[i]->nodes);
     }
-  sbitmap_free (tmp);
 }
 
 /* Perform the Strongly Connected Components decomposing algorithm on the
@@ -1018,9 +1017,9 @@ create_ddg_all_sccs (ddg_ptr g)
 {
   int i;
   int num_nodes = g->num_nodes;
-  sbitmap from = sbitmap_alloc (num_nodes);
-  sbitmap to = sbitmap_alloc (num_nodes);
-  sbitmap scc_nodes = sbitmap_alloc (num_nodes);
+  auto_sbitmap from (num_nodes);
+  auto_sbitmap to (num_nodes);
+  auto_sbitmap scc_nodes (num_nodes);
   ddg_all_sccs_ptr sccs = (ddg_all_sccs_ptr)
 			  xmalloc (sizeof (struct ddg_all_sccs));
 
@@ -1052,9 +1051,6 @@ create_ddg_all_sccs (ddg_ptr g)
 	}
     }
   order_sccs (sccs);
-  sbitmap_free (from);
-  sbitmap_free (to);
-  sbitmap_free (scc_nodes);
 
   if (flag_checking)
     check_sccs (sccs, num_nodes);
diff --git a/gcc/df-core.c b/gcc/df-core.c
index c1e9714..cc18a13 100644
--- a/gcc/df-core.c
+++ b/gcc/df-core.c
@@ -1083,7 +1083,6 @@ df_worklist_dataflow (struct dataflow *dataflow,
                       int n_blocks)
 {
   bitmap pending = BITMAP_ALLOC (&df_bitmap_obstack);
-  sbitmap considered = sbitmap_alloc (last_basic_block_for_fn (cfun));
   bitmap_iterator bi;
   unsigned int *bbindex_to_postorder;
   int i;
@@ -1101,6 +1100,7 @@ df_worklist_dataflow (struct dataflow *dataflow,
     bbindex_to_postorder[i] = last_basic_block_for_fn (cfun);
 
   /* Initialize the considered map.  */
+  auto_sbitmap considered (last_basic_block_for_fn (cfun));
   bitmap_clear (considered);
   EXECUTE_IF_SET_IN_BITMAP (blocks_to_consider, 0, index, bi)
     {
@@ -1124,7 +1124,6 @@ df_worklist_dataflow (struct dataflow *dataflow,
 				    blocks_in_postorder,
 				    bbindex_to_postorder,
 				    n_blocks);
-  sbitmap_free (considered);
   free (bbindex_to_postorder);
 }
 
diff --git a/gcc/dse.c b/gcc/dse.c
index 05a2886..17312c5 100644
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -2999,11 +2999,11 @@ static void
 dse_step3 ()
 {
   basic_block bb;
-  sbitmap unreachable_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
   sbitmap_iterator sbi;
   bitmap all_ones = NULL;
   unsigned int i;
 
+  auto_sbitmap unreachable_blocks (last_basic_block_for_fn (cfun));
   bitmap_ones (unreachable_blocks);
 
   FOR_ALL_BB_FN (bb, cfun)
@@ -3058,7 +3058,6 @@ dse_step3 ()
 
   if (all_ones)
     BITMAP_FREE (all_ones);
-  sbitmap_free (unreachable_blocks);
 }
 
 
diff --git a/gcc/except.c b/gcc/except.c
index e494915..8aeb4e8 100644
--- a/gcc/except.c
+++ b/gcc/except.c
@@ -634,12 +634,10 @@ eh_region
 eh_region_outermost (struct function *ifun, eh_region region_a,
 		     eh_region region_b)
 {
-  sbitmap b_outer;
-
   gcc_assert (ifun->eh->region_array);
   gcc_assert (ifun->eh->region_tree);
 
-  b_outer = sbitmap_alloc (ifun->eh->region_array->length ());
+  auto_sbitmap b_outer (ifun->eh->region_array->length ());
   bitmap_clear (b_outer);
 
   do
@@ -657,7 +655,6 @@ eh_region_outermost (struct function *ifun, eh_region region_a,
     }
   while (region_a);
 
-  sbitmap_free (b_outer);
   return region_a;
 }
 
diff --git a/gcc/function.c b/gcc/function.c
index 269ed8d..bba0705 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -6018,12 +6018,11 @@ thread_prologue_and_epilogue_insns (void)
       commit_edge_insertions ();
 
       /* Look for basic blocks within the prologue insns.  */
-      sbitmap blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+      auto_sbitmap blocks (last_basic_block_for_fn (cfun));
       bitmap_clear (blocks);
       bitmap_set_bit (blocks, entry_edge->dest->index);
       bitmap_set_bit (blocks, orig_entry_edge->dest->index);
       find_many_sub_basic_blocks (blocks);
-      sbitmap_free (blocks);
     }
 
   default_rtl_profile ();
diff --git a/gcc/gcse.c b/gcc/gcse.c
index 49534f2..c2c0e8e 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -1691,12 +1691,11 @@ free_pre_mem (void)
 static void
 prune_expressions (bool pre_p)
 {
-  sbitmap prune_exprs;
   struct gcse_expr *expr;
   unsigned int ui;
   basic_block bb;
 
-  prune_exprs = sbitmap_alloc (expr_hash_table.n_elems);
+  auto_sbitmap prune_exprs (expr_hash_table.n_elems);
   bitmap_clear (prune_exprs);
   for (ui = 0; ui < expr_hash_table.size; ui++)
     {
@@ -1767,8 +1766,6 @@ prune_expressions (bool pre_p)
 	    break;
 	  }
     }
-
-  sbitmap_free (prune_exprs);
 }
 
 /* It may be necessary to insert a large number of insns on edges to
@@ -1783,7 +1780,6 @@ static void
 prune_insertions_deletions (int n_elems)
 {
   sbitmap_iterator sbi;
-  sbitmap prune_exprs;
 
   /* We always use I to iterate over blocks/edges and J to iterate over
      expressions.  */
@@ -1797,7 +1793,7 @@ prune_insertions_deletions (int n_elems)
   /* Set of expressions which require too many insertions relative to
      the number of deletions achieved.  We will prune these out of the
      insertion/deletion sets.  */
-  prune_exprs = sbitmap_alloc (n_elems);
+  auto_sbitmap prune_exprs (n_elems);
   bitmap_clear (prune_exprs);
 
   /* Iterate over the edges counting the number of times each expression
@@ -1835,7 +1831,6 @@ prune_insertions_deletions (int n_elems)
 	bitmap_clear_bit (pre_delete_map[i], j);
     }
 
-  sbitmap_free (prune_exprs);
   free (insertions);
   free (deletions);
 }
diff --git a/gcc/gimple-ssa-backprop.c b/gcc/gimple-ssa-backprop.c
index d96bcca..53349e8 100644
--- a/gcc/gimple-ssa-backprop.c
+++ b/gcc/gimple-ssa-backprop.c
@@ -258,7 +258,7 @@ private:
 
   /* A bitmap of blocks that we have finished processing in the initial
      post-order walk.  */
-  sbitmap m_visited_blocks;
+  auto_sbitmap m_visited_blocks;
 
   /* A worklist of SSA names whose definitions need to be reconsidered.  */
   auto_vec <tree, 64> m_worklist;
@@ -272,7 +272,7 @@ private:
 backprop::backprop (function *fn)
   : m_fn (fn),
     m_info_pool ("usage_info"),
-    m_visited_blocks (sbitmap_alloc (last_basic_block_for_fn (m_fn))),
+    m_visited_blocks (last_basic_block_for_fn (m_fn)),
     m_worklist_names (BITMAP_ALLOC (NULL))
 {
   bitmap_clear (m_visited_blocks);
@@ -281,7 +281,6 @@ backprop::backprop (function *fn)
 backprop::~backprop ()
 {
   BITMAP_FREE (m_worklist_names);
-  sbitmap_free (m_visited_blocks);
   m_info_pool.release ();
 }
 
diff --git a/gcc/graph.c b/gcc/graph.c
index dd5bc4e..d3e2d2e 100644
--- a/gcc/graph.c
+++ b/gcc/graph.c
@@ -156,9 +156,8 @@ draw_cfg_nodes_no_loops (pretty_printer *pp, struct function *fun)
 {
   int *rpo = XNEWVEC (int, n_basic_blocks_for_fn (fun));
   int i, n;
-  sbitmap visited;
 
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
   bitmap_clear (visited);
 
   n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, true);
@@ -179,8 +178,6 @@ draw_cfg_nodes_no_loops (pretty_printer *pp, struct function *fun)
 	if (! bitmap_bit_p (visited, bb->index))
 	  draw_cfg_node (pp, fun->funcdef_no, bb);
     }
-
-  sbitmap_free (visited);
 }
 
 /* Draw all the basic blocks in LOOP.  Print the blocks in breath-first
diff --git a/gcc/ira-lives.c b/gcc/ira-lives.c
index 6b7ee81..ff6d100 100644
--- a/gcc/ira-lives.c
+++ b/gcc/ira-lives.c
@@ -1409,12 +1409,11 @@ remove_some_program_points_and_update_live_ranges (void)
   ira_object_t obj;
   ira_object_iterator oi;
   live_range_t r, prev_r, next_r;
-  sbitmap born_or_dead, born, dead;
   sbitmap_iterator sbi;
   bool born_p, dead_p, prev_born_p, prev_dead_p;
   
-  born = sbitmap_alloc (ira_max_point);
-  dead = sbitmap_alloc (ira_max_point);
+  auto_sbitmap born (ira_max_point);
+  auto_sbitmap dead (ira_max_point);
   bitmap_clear (born);
   bitmap_clear (dead);
   FOR_EACH_OBJECT (obj, oi)
@@ -1425,7 +1424,7 @@ remove_some_program_points_and_update_live_ranges (void)
 	bitmap_set_bit (dead, r->finish);
       }
 
-  born_or_dead = sbitmap_alloc (ira_max_point);
+  auto_sbitmap born_or_dead (ira_max_point);
   bitmap_ior (born_or_dead, born, dead);
   map = (int *) ira_allocate (sizeof (int) * ira_max_point);
   n = -1;
@@ -1442,9 +1441,7 @@ remove_some_program_points_and_update_live_ranges (void)
       prev_born_p = born_p;
       prev_dead_p = dead_p;
     }
-  sbitmap_free (born_or_dead);
-  sbitmap_free (born);
-  sbitmap_free (dead);
+
   n++;
   if (internal_flag_ira_verbose > 1 && ira_dump_file != NULL)
     fprintf (ira_dump_file, "Compressing live ranges: from %d to %d - %d%%\n",
diff --git a/gcc/lcm.c b/gcc/lcm.c
index 948e7bc..4754338 100644
--- a/gcc/lcm.c
+++ b/gcc/lcm.c
@@ -170,15 +170,12 @@ compute_earliest (struct edge_list *edge_list, int n_exprs, sbitmap *antin,
 		  sbitmap *antout, sbitmap *avout, sbitmap *kill,
 		  sbitmap *earliest)
 {
-  sbitmap difference, temp_bitmap;
   int x, num_edges;
   basic_block pred, succ;
 
   num_edges = NUM_EDGES (edge_list);
 
-  difference = sbitmap_alloc (n_exprs);
-  temp_bitmap = sbitmap_alloc (n_exprs);
-
+  auto_sbitmap difference (n_exprs), temp_bitmap (n_exprs);
   for (x = 0; x < num_edges; x++)
     {
       pred = INDEX_EDGE_PRED_BB (edge_list, x);
@@ -199,9 +196,6 @@ compute_earliest (struct edge_list *edge_list, int n_exprs, sbitmap *antin,
 	    }
 	}
     }
-
-  sbitmap_free (temp_bitmap);
-  sbitmap_free (difference);
 }
 
 /* later(p,s) is dependent on the calculation of laterin(p).
@@ -594,15 +588,12 @@ compute_farthest (struct edge_list *edge_list, int n_exprs,
 		  sbitmap *st_avout, sbitmap *st_avin, sbitmap *st_antin,
 		  sbitmap *kill, sbitmap *farthest)
 {
-  sbitmap difference, temp_bitmap;
   int x, num_edges;
   basic_block pred, succ;
 
   num_edges = NUM_EDGES (edge_list);
 
-  difference = sbitmap_alloc (n_exprs);
-  temp_bitmap = sbitmap_alloc (n_exprs);
-
+  auto_sbitmap difference (n_exprs), temp_bitmap (n_exprs);
   for (x = 0; x < num_edges; x++)
     {
       pred = INDEX_EDGE_PRED_BB (edge_list, x);
@@ -623,9 +614,6 @@ compute_farthest (struct edge_list *edge_list, int n_exprs,
 	    }
 	}
     }
-
-  sbitmap_free (temp_bitmap);
-  sbitmap_free (difference);
 }
 
 /* Compute nearer and nearerout vectors for edge based lcm.
diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
index 42b1548..b568ea5 100644
--- a/gcc/loop-unroll.c
+++ b/gcc/loop-unroll.c
@@ -461,7 +461,6 @@ unroll_loop_constant_iterations (struct loop *loop)
 {
   unsigned HOST_WIDE_INT niter;
   unsigned exit_mod;
-  sbitmap wont_exit;
   unsigned i;
   edge e;
   unsigned max_unroll = loop->lpt_decision.times;
@@ -477,7 +476,7 @@ unroll_loop_constant_iterations (struct loop *loop)
 
   exit_mod = niter % (max_unroll + 1);
 
-  wont_exit = sbitmap_alloc (max_unroll + 1);
+  auto_sbitmap wont_exit (max_unroll + 1);
   bitmap_ones (wont_exit);
 
   auto_vec<edge> remove_edges;
@@ -604,8 +603,6 @@ unroll_loop_constant_iterations (struct loop *loop)
       free_opt_info (opt_info);
     }
 
-  free (wont_exit);
-
   if (exit_at_end)
     {
       basic_block exit_block = get_bb_copy (desc->in_edge->src);
@@ -861,7 +858,6 @@ unroll_loop_runtime_iterations (struct loop *loop)
   rtx_insn *init_code, *branch_code;
   unsigned i, j, p;
   basic_block preheader, *body, swtch, ezc_swtch;
-  sbitmap wont_exit;
   int may_exit_copy;
   unsigned n_peel;
   edge e;
@@ -936,7 +932,7 @@ unroll_loop_runtime_iterations (struct loop *loop)
 
   auto_vec<edge> remove_edges;
 
-  wont_exit = sbitmap_alloc (max_unroll + 2);
+  auto_sbitmap wont_exit (max_unroll + 2);
 
   /* Peel the first copy of loop body (almost always we must leave exit test
      here; the only exception is when we have extra zero check and the number
@@ -1035,8 +1031,6 @@ unroll_loop_runtime_iterations (struct loop *loop)
       free_opt_info (opt_info);
     }
 
-  free (wont_exit);
-
   if (exit_at_end)
     {
       basic_block exit_block = get_bb_copy (desc->in_edge->src);
@@ -1201,7 +1195,6 @@ decide_unroll_stupid (struct loop *loop, int flags)
 static void
 unroll_loop_stupid (struct loop *loop)
 {
-  sbitmap wont_exit;
   unsigned nunroll = loop->lpt_decision.times;
   struct niter_desc *desc = get_simple_loop_desc (loop);
   struct opt_info *opt_info = NULL;
@@ -1211,8 +1204,7 @@ unroll_loop_stupid (struct loop *loop)
       || flag_variable_expansion_in_unroller)
     opt_info = analyze_insns_in_loop (loop);
 
-
-  wont_exit = sbitmap_alloc (nunroll + 1);
+  auto_sbitmap wont_exit (nunroll + 1);
   bitmap_clear (wont_exit);
   opt_info_start_duplication (opt_info);
 
@@ -1231,8 +1223,6 @@ unroll_loop_stupid (struct loop *loop)
       free_opt_info (opt_info);
     }
 
-  free (wont_exit);
-
   if (desc->simple_p)
     {
       /* We indeed may get here provided that there are nontrivial assumptions
diff --git a/gcc/lower-subreg.c b/gcc/lower-subreg.c
index f7b3ac4..4ea763b 100644
--- a/gcc/lower-subreg.c
+++ b/gcc/lower-subreg.c
@@ -1507,7 +1507,6 @@ decompose_multiword_subregs (bool decompose_copies)
   bitmap_and_compl_into (decomposable_context, non_decomposable_context);
   if (!bitmap_empty_p (decomposable_context))
     {
-      sbitmap sub_blocks;
       unsigned int i;
       sbitmap_iterator sbi;
       bitmap_iterator iter;
@@ -1515,7 +1514,7 @@ decompose_multiword_subregs (bool decompose_copies)
 
       propagate_pseudo_copies ();
 
-      sub_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+      auto_sbitmap sub_blocks (last_basic_block_for_fn (cfun));
       bitmap_clear (sub_blocks);
 
       EXECUTE_IF_SET_IN_BITMAP (decomposable_context, 0, regno, iter)
@@ -1643,8 +1642,6 @@ decompose_multiword_subregs (bool decompose_copies)
 	        insn = NEXT_INSN (insn);
 	    }
 	}
-
-      sbitmap_free (sub_blocks);
     }
 
   {
diff --git a/gcc/lra-lives.c b/gcc/lra-lives.c
index 8811198..f761da5 100644
--- a/gcc/lra-lives.c
+++ b/gcc/lra-lives.c
@@ -1015,12 +1015,11 @@ remove_some_program_points_and_update_live_ranges (void)
   int n, max_regno;
   int *map;
   lra_live_range_t r, prev_r, next_r;
-  sbitmap born_or_dead, born, dead;
   sbitmap_iterator sbi;
   bool born_p, dead_p, prev_born_p, prev_dead_p;
 
-  born = sbitmap_alloc (lra_live_max_point);
-  dead = sbitmap_alloc (lra_live_max_point);
+  auto_sbitmap born (lra_live_max_point);
+  auto_sbitmap dead (lra_live_max_point);
   bitmap_clear (born);
   bitmap_clear (dead);
   max_regno = max_reg_num ();
@@ -1033,7 +1032,7 @@ remove_some_program_points_and_update_live_ranges (void)
 	  bitmap_set_bit (dead, r->finish);
 	}
     }
-  born_or_dead = sbitmap_alloc (lra_live_max_point);
+  auto_sbitmap born_or_dead (lra_live_max_point);
   bitmap_ior (born_or_dead, born, dead);
   map = XCNEWVEC (int, lra_live_max_point);
   n = -1;
@@ -1056,9 +1055,6 @@ remove_some_program_points_and_update_live_ranges (void)
       prev_born_p = born_p;
       prev_dead_p = dead_p;
     }
-  sbitmap_free (born_or_dead);
-  sbitmap_free (born);
-  sbitmap_free (dead);
   n++;
   if (lra_dump_file != NULL)
     fprintf (lra_dump_file, "Compressing live ranges: from %d to %d - %d%%\n",
diff --git a/gcc/lra.c b/gcc/lra.c
index a724ef7..a63e393 100644
--- a/gcc/lra.c
+++ b/gcc/lra.c
@@ -2413,11 +2413,9 @@ lra (FILE *f)
   /* We've possibly turned single trapping insn into multiple ones.  */
   if (cfun->can_throw_non_call_exceptions)
     {
-      sbitmap blocks;
-      blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+      auto_sbitmap blocks (last_basic_block_for_fn (cfun));
       bitmap_ones (blocks);
       find_many_sub_basic_blocks (blocks);
-      sbitmap_free (blocks);
     }
 
   if (inserted_p)
diff --git a/gcc/modulo-sched.c b/gcc/modulo-sched.c
index 5dde66c..6e87a6f 100644
--- a/gcc/modulo-sched.c
+++ b/gcc/modulo-sched.c
@@ -682,7 +682,6 @@ schedule_reg_moves (partial_schedule_ptr ps)
       rtx prev_reg, old_reg;
       int first_move;
       int distances[2];
-      sbitmap must_follow;
       sbitmap distance1_uses;
       rtx set = single_set (u->insn);
       
@@ -792,12 +791,11 @@ schedule_reg_moves (partial_schedule_ptr ps)
 	      }
 	  }
 
-      must_follow = sbitmap_alloc (first_move + nreg_moves);
+      auto_sbitmap must_follow (first_move + nreg_moves);
       for (i_reg_move = 0; i_reg_move < nreg_moves; i_reg_move++)
 	if (!schedule_reg_move (ps, first_move + i_reg_move,
 				distance1_uses, must_follow))
 	  break;
-      sbitmap_free (must_follow);
       if (distance1_uses)
 	sbitmap_free (distance1_uses);
       if (i_reg_move < nreg_moves)
@@ -927,7 +925,6 @@ static bool
 optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
 {
   int amount = PS_MIN_CYCLE (ps);
-  sbitmap sched_nodes = sbitmap_alloc (g->num_nodes);
   int start, end, step;
   int ii = ps->ii;
   bool ok = false;
@@ -944,8 +941,7 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
       if (dump_file)
 	fprintf (dump_file, "SMS SC already optimized.\n");
 
-      ok = false;
-      goto clear;
+      return false;
     }
 
   if (dump_file)
@@ -967,11 +963,9 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
     }
 
   if (SMODULO (SCHED_TIME (g->closing_branch->cuid), ii) == ii - 1)
-    {
-      ok = true;
-      goto clear;
-    }
+    return true;
 
+  auto_sbitmap sched_nodes (g->num_nodes);
   bitmap_ones (sched_nodes);
 
   /* Calculate the new placement of the branch.  It should be in row
@@ -984,7 +978,7 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
       int branch_cycle = SCHED_TIME (g->closing_branch->cuid);
       int row = SMODULO (branch_cycle, ps->ii);
       int num_splits = 0;
-      sbitmap must_precede, must_follow, tmp_precede, tmp_follow;
+      sbitmap tmp_precede, tmp_follow;
       int min_cycle, c;
 
       if (dump_file)
@@ -1000,11 +994,10 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
 	  gcc_assert (c >= start);
 	  if (c >= end)
 	    {
-	      ok = false;
 	      if (dump_file)
 		fprintf (dump_file,
 			 "SMS failed to schedule branch at cycle: %d\n", c);
-	      goto clear;
+	      return false;
 	    }
 	}
       else
@@ -1017,13 +1010,12 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
 	      if (dump_file)
 		fprintf (dump_file,
 			 "SMS failed to schedule branch at cycle: %d\n", c);
-	      ok = false;
-	      goto clear;
+	      return false;
 	    }
 	}
 
-      must_precede = sbitmap_alloc (g->num_nodes);
-      must_follow = sbitmap_alloc (g->num_nodes);
+      auto_sbitmap must_precede (g->num_nodes);
+      auto_sbitmap must_follow (g->num_nodes);
 
       /* Try to schedule the branch is it's new cycle.  */
       calculate_must_precede_follow (g->closing_branch, start, end,
@@ -1083,13 +1075,8 @@ optimize_sc (partial_schedule_ptr ps, ddg_ptr g)
       /* This might have been added to a new first stage.  */
       if (PS_MIN_CYCLE (ps) < min_cycle)
 	reset_sched_times (ps, 0);
-
-      free (must_precede);
-      free (must_follow);
     }
 
-clear:
-  free (sched_nodes);
   return ok;
 }
 
@@ -1866,8 +1853,8 @@ get_sched_window (partial_schedule_ptr ps, ddg_node_ptr u_node,
   int start, step, end;
   int early_start, late_start;
   ddg_edge_ptr e;
-  sbitmap psp = sbitmap_alloc (ps->g->num_nodes);
-  sbitmap pss = sbitmap_alloc (ps->g->num_nodes);
+  auto_sbitmap psp (ps->g->num_nodes);
+  auto_sbitmap pss (ps->g->num_nodes);
   sbitmap u_node_preds = NODE_PREDECESSORS (u_node);
   sbitmap u_node_succs = NODE_SUCCESSORS (u_node);
   int psp_not_empty;
@@ -1996,8 +1983,6 @@ get_sched_window (partial_schedule_ptr ps, ddg_node_ptr u_node,
   *start_p = start;
   *step_p = step;
   *end_p = end;
-  sbitmap_free (psp);
-  sbitmap_free (pss);
 
   if ((start >= end && step == 1) || (start <= end && step == -1))
     {
@@ -2146,10 +2131,10 @@ sms_schedule_by_order (ddg_ptr g, int mii, int maxii, int *nodes_order)
   int flush_and_start_over = true;
   int num_nodes = g->num_nodes;
   int start, end, step; /* Place together into one struct?  */
-  sbitmap sched_nodes = sbitmap_alloc (num_nodes);
-  sbitmap must_precede = sbitmap_alloc (num_nodes);
-  sbitmap must_follow = sbitmap_alloc (num_nodes);
-  sbitmap tobe_scheduled = sbitmap_alloc (num_nodes);
+  auto_sbitmap sched_nodes (num_nodes);
+  auto_sbitmap must_precede (num_nodes);
+  auto_sbitmap must_follow (num_nodes);
+  auto_sbitmap tobe_scheduled (num_nodes);
 
   partial_schedule_ptr ps = create_partial_schedule (ii, g, DFA_HISTORY);
 
@@ -2260,11 +2245,6 @@ sms_schedule_by_order (ddg_ptr g, int mii, int maxii, int *nodes_order)
   else
     gcc_assert (bitmap_equal_p (tobe_scheduled, sched_nodes));
 
-  sbitmap_free (sched_nodes);
-  sbitmap_free (must_precede);
-  sbitmap_free (must_follow);
-  sbitmap_free (tobe_scheduled);
-
   return ps;
 }
 
@@ -2474,7 +2454,7 @@ static void
 check_nodes_order (int *node_order, int num_nodes)
 {
   int i;
-  sbitmap tmp = sbitmap_alloc (num_nodes);
+  auto_sbitmap tmp (num_nodes);
 
   bitmap_clear (tmp);
 
@@ -2494,8 +2474,6 @@ check_nodes_order (int *node_order, int num_nodes)
 
   if (dump_file)
     fprintf (dump_file, "\n");
-
-  sbitmap_free (tmp);
 }
 
 /* Order the nodes of G for scheduling and pass the result in
@@ -2539,10 +2517,10 @@ order_nodes_of_sccs (ddg_all_sccs_ptr all_sccs, int * node_order)
   int i, pos = 0;
   ddg_ptr g = all_sccs->ddg;
   int num_nodes = g->num_nodes;
-  sbitmap prev_sccs = sbitmap_alloc (num_nodes);
-  sbitmap on_path = sbitmap_alloc (num_nodes);
-  sbitmap tmp = sbitmap_alloc (num_nodes);
-  sbitmap ones = sbitmap_alloc (num_nodes);
+  auto_sbitmap prev_sccs (num_nodes);
+  auto_sbitmap on_path (num_nodes);
+  auto_sbitmap tmp (num_nodes);
+  auto_sbitmap ones (num_nodes);
 
   bitmap_clear (prev_sccs);
   bitmap_ones (ones);
@@ -2575,10 +2553,6 @@ order_nodes_of_sccs (ddg_all_sccs_ptr all_sccs, int * node_order)
       bitmap_and_compl (tmp, ones, prev_sccs);
       pos = order_nodes_in_scc (g, prev_sccs, tmp, node_order, pos);
     }
-  sbitmap_free (prev_sccs);
-  sbitmap_free (on_path);
-  sbitmap_free (tmp);
-  sbitmap_free (ones);
 }
 
 /* MII is needed if we consider backarcs (that do not close recursive cycles).  */
@@ -2739,11 +2713,11 @@ order_nodes_in_scc (ddg_ptr g, sbitmap nodes_ordered, sbitmap scc,
 {
   enum sms_direction dir;
   int num_nodes = g->num_nodes;
-  sbitmap workset = sbitmap_alloc (num_nodes);
-  sbitmap tmp = sbitmap_alloc (num_nodes);
+  auto_sbitmap workset (num_nodes);
+  auto_sbitmap tmp (num_nodes);
   sbitmap zero_bitmap = sbitmap_alloc (num_nodes);
-  sbitmap predecessors = sbitmap_alloc (num_nodes);
-  sbitmap successors = sbitmap_alloc (num_nodes);
+  auto_sbitmap predecessors (num_nodes);
+  auto_sbitmap successors (num_nodes);
 
   bitmap_clear (predecessors);
   find_predecessors (predecessors, g, nodes_ordered);
@@ -2823,11 +2797,7 @@ order_nodes_in_scc (ddg_ptr g, sbitmap nodes_ordered, sbitmap scc,
 	  bitmap_and (workset, successors, scc);
 	}
     }
-  sbitmap_free (tmp);
-  sbitmap_free (workset);
   sbitmap_free (zero_bitmap);
-  sbitmap_free (predecessors);
-  sbitmap_free (successors);
   return pos;
 }
 
diff --git a/gcc/recog.c b/gcc/recog.c
index 80d1779..f425e47 100644
--- a/gcc/recog.c
+++ b/gcc/recog.c
@@ -2935,11 +2935,10 @@ split_insn (rtx_insn *insn)
 void
 split_all_insns (void)
 {
-  sbitmap blocks;
   bool changed;
   basic_block bb;
 
-  blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap blocks (last_basic_block_for_fn (cfun));
   bitmap_clear (blocks);
   changed = false;
 
@@ -2989,8 +2988,6 @@ split_all_insns (void)
     find_many_sub_basic_blocks (blocks);
 
   checking_verify_flow_info ();
-
-  sbitmap_free (blocks);
 }
 
 /* Same as split_all_insns, but do not expect CFG to be available.
diff --git a/gcc/regcprop.c b/gcc/regcprop.c
index 933cc8a..1498300 100644
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -1238,12 +1238,11 @@ pass_cprop_hardreg::execute (function *fun)
 {
   struct value_data *all_vd;
   basic_block bb;
-  sbitmap visited;
   bool analyze_called = false;
 
   all_vd = XNEWVEC (struct value_data, last_basic_block_for_fn (fun));
 
-  visited = sbitmap_alloc (last_basic_block_for_fn (fun));
+  auto_sbitmap visited (last_basic_block_for_fn (fun));
   bitmap_clear (visited);
 
   FOR_EACH_BB_FN (bb, fun)
@@ -1308,7 +1307,6 @@ pass_cprop_hardreg::execute (function *fun)
       queued_debug_insn_change_pool.release ();
     }
 
-  sbitmap_free (visited);
   free (all_vd);
   return 0;
 }
diff --git a/gcc/reload1.c b/gcc/reload1.c
index 5622e89..ce042bf 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -1280,11 +1280,9 @@ reload (rtx_insn *first, int global)
   /* We've possibly turned single trapping insn into multiple ones.  */
   if (cfun->can_throw_non_call_exceptions)
     {
-      sbitmap blocks;
-      blocks = sbitmap_alloc (last_basic_block_for_fn (cfun));
+      auto_sbitmap blocks (last_basic_block_for_fn (cfun));
       bitmap_ones (blocks);
       find_many_sub_basic_blocks (blocks);
-      sbitmap_free (blocks);
     }
 
   if (inserted)
diff --git a/gcc/sched-rgn.c b/gcc/sched-rgn.c
index fa662ff..bfb8d8f 100644
--- a/gcc/sched-rgn.c
+++ b/gcc/sched-rgn.c
@@ -623,18 +623,6 @@ haifa_find_rgns (void)
   int too_large_failure;
   basic_block bb;
 
-  /* Note if a block is a natural loop header.  */
-  sbitmap header;
-
-  /* Note if a block is a natural inner loop header.  */
-  sbitmap inner;
-
-  /* Note if a block is in the block queue.  */
-  sbitmap in_queue;
-
-  /* Note if a block is in the block queue.  */
-  sbitmap in_stack;
-
   /* Perform a DFS traversal of the cfg.  Identify loop headers, inner loops
      and a mapping from block to its loop header (if the block is contained
      in a loop, else -1).
@@ -649,16 +637,20 @@ haifa_find_rgns (void)
   dfs_nr = XCNEWVEC (int, last_basic_block_for_fn (cfun));
   stack = XNEWVEC (edge_iterator, n_edges_for_fn (cfun));
 
-  inner = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  /* Note if a block is a natural inner loop header.  */
+  auto_sbitmap inner (last_basic_block_for_fn (cfun));
   bitmap_ones (inner);
 
-  header = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  /* Note if a block is a natural loop header.  */
+  auto_sbitmap header (last_basic_block_for_fn (cfun));
   bitmap_clear (header);
 
-  in_queue = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  /* Note if a block is in the block queue.  */
+  auto_sbitmap in_queue (last_basic_block_for_fn (cfun));
   bitmap_clear (in_queue);
 
-  in_stack = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  /* Note if a block is in the block queue.  */
+  auto_sbitmap in_stack (last_basic_block_for_fn (cfun));
   bitmap_clear (in_stack);
 
   for (i = 0; i < last_basic_block_for_fn (cfun); i++)
@@ -1070,10 +1062,6 @@ haifa_find_rgns (void)
   free (max_hdr);
   free (degree);
   free (stack);
-  sbitmap_free (header);
-  sbitmap_free (inner);
-  sbitmap_free (in_queue);
-  sbitmap_free (in_stack);
 }
 
 
@@ -1477,12 +1465,11 @@ compute_dom_prob_ps (int bb)
 static void
 split_edges (int bb_src, int bb_trg, edgelst *bl)
 {
-  sbitmap src = sbitmap_alloc (SBITMAP_SIZE (pot_split[bb_src]));
+  auto_sbitmap src (SBITMAP_SIZE (pot_split[bb_src]));
   bitmap_copy (src, pot_split[bb_src]);
 
   bitmap_and_compl (src, src, pot_split[bb_trg]);
   extract_edgelst (src, bl);
-  sbitmap_free (src);
 }
 
 /* Find the valid candidate-source-blocks for the target block TRG, compute
@@ -1496,7 +1483,6 @@ compute_trg_info (int trg)
   edgelst el = { NULL, 0 };
   int i, j, k, update_idx;
   basic_block block;
-  sbitmap visited;
   edge_iterator ei;
   edge e;
 
@@ -1519,7 +1505,7 @@ compute_trg_info (int trg)
   sp->is_speculative = 0;
   sp->src_prob = REG_BR_PROB_BASE;
 
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
 
   for (i = trg + 1; i < current_nr_blocks; i++)
     {
@@ -1595,8 +1581,6 @@ compute_trg_info (int trg)
 	  sp->src_prob = 0;
 	}
     }
-
-  sbitmap_free (visited);
 }
 
 /* Free the computed target info.  */
diff --git a/gcc/sel-sched.c b/gcc/sel-sched.c
index b795aea..25a100e 100644
--- a/gcc/sel-sched.c
+++ b/gcc/sel-sched.c
@@ -6764,11 +6764,10 @@ init_seqno_1 (basic_block bb, sbitmap visited_bbs, bitmap blocks_to_reschedule)
 static int
 init_seqno (bitmap blocks_to_reschedule, basic_block from)
 {
-  sbitmap visited_bbs;
   bitmap_iterator bi;
   unsigned bbi;
 
-  visited_bbs = sbitmap_alloc (current_nr_blocks);
+  auto_sbitmap visited_bbs (current_nr_blocks);
 
   if (blocks_to_reschedule)
     {
@@ -6793,7 +6792,6 @@ init_seqno (bitmap blocks_to_reschedule, basic_block from)
      removed by the call to purge_empty_blocks in sel_sched_region_1).  */
   gcc_assert (cur_seqno >= 0);
 
-  sbitmap_free (visited_bbs);
   return sched_max_luid - 1;
 }
 
diff --git a/gcc/store-motion.c b/gcc/store-motion.c
index 6d7d37f..1d504e7 100644
--- a/gcc/store-motion.c
+++ b/gcc/store-motion.c
@@ -825,7 +825,7 @@ remove_reachable_equiv_notes (basic_block bb, struct st_expr *smexpr)
   edge_iterator *stack, ei;
   int sp;
   edge act;
-  sbitmap visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
   rtx note;
   rtx_insn *insn;
   rtx mem = smexpr->pattern;
@@ -844,7 +844,6 @@ remove_reachable_equiv_notes (basic_block bb, struct st_expr *smexpr)
 	  if (!sp)
 	    {
 	      free (stack);
-	      sbitmap_free (visited);
 	      return;
 	    }
 	  act = ei_edge (stack[--sp]);
diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c
index f83cad2..ec522f1 100644
--- a/gcc/tree-into-ssa.c
+++ b/gcc/tree-into-ssa.c
@@ -3322,12 +3322,11 @@ update_ssa (unsigned update_flags)
 	     will grow while we are traversing it (but it will not
 	     gain any new members).  Copy OLD_SSA_NAMES to a temporary
 	     for traversal.  */
-	  sbitmap tmp = sbitmap_alloc (SBITMAP_SIZE (old_ssa_names));
+	  auto_sbitmap tmp (SBITMAP_SIZE (old_ssa_names));
 	  bitmap_copy (tmp, old_ssa_names);
 	  EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi)
 	    insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update,
 	                                  update_flags);
-	  sbitmap_free (tmp);
 	}
 
       symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids);
diff --git a/gcc/tree-ssa-live.c b/gcc/tree-ssa-live.c
index 15fc43f..72ee4e3 100644
--- a/gcc/tree-ssa-live.c
+++ b/gcc/tree-ssa-live.c
@@ -975,7 +975,7 @@ live_worklist (tree_live_info_p live)
 {
   unsigned b;
   basic_block bb;
-  sbitmap visited = sbitmap_alloc (last_basic_block_for_fn (cfun) + 1);
+  auto_sbitmap visited (last_basic_block_for_fn (cfun) + 1);
 
   bitmap_clear (visited);
 
@@ -990,8 +990,6 @@ live_worklist (tree_live_info_p live)
       b = *--(live->stack_top);
       loe_visit_block (live, BASIC_BLOCK_FOR_FN (cfun, b), visited);
     }
-
-  sbitmap_free (visited);
 }
 
 
diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c
index 278f60a..c5aaef3 100644
--- a/gcc/tree-ssa-loop-im.c
+++ b/gcc/tree-ssa-loop-im.c
@@ -2409,10 +2409,10 @@ fill_always_executed_in_1 (struct loop *loop, sbitmap contains_call)
 static void
 fill_always_executed_in (void)
 {
-  sbitmap contains_call = sbitmap_alloc (last_basic_block_for_fn (cfun));
   basic_block bb;
   struct loop *loop;
 
+  auto_sbitmap contains_call (last_basic_block_for_fn (cfun));
   bitmap_clear (contains_call);
   FOR_EACH_BB_FN (bb, cfun)
     {
@@ -2429,8 +2429,6 @@ fill_always_executed_in (void)
 
   for (loop = current_loops->tree_root->inner; loop; loop = loop->next)
     fill_always_executed_in_1 (loop, contains_call);
-
-  sbitmap_free (contains_call);
 }
 
 
diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
index 76ecba4..beb65b0 100644
--- a/gcc/tree-ssa-loop-ivcanon.c
+++ b/gcc/tree-ssa-loop-ivcanon.c
@@ -743,7 +743,6 @@ try_unroll_loop_completely (struct loop *loop,
 
   if (n_unroll)
     {
-      sbitmap wont_exit;
       bool large;
       if (ul == UL_SINGLE_ITER)
 	return false;
@@ -860,7 +859,7 @@ try_unroll_loop_completely (struct loop *loop,
                        "loop turned into non-loop; it never loops.\n");
 
       initialize_original_copy_tables ();
-      wont_exit = sbitmap_alloc (n_unroll + 1);
+      auto_sbitmap wont_exit (n_unroll + 1);
       if (exit && niter
 	  && TREE_CODE (niter) == INTEGER_CST
 	  && wi::leu_p (n_unroll, wi::to_widest (niter)))
@@ -883,13 +882,11 @@ try_unroll_loop_completely (struct loop *loop,
 						 | DLTHE_FLAG_COMPLETTE_PEEL))
 	{
           free_original_copy_tables ();
-	  free (wont_exit);
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    fprintf (dump_file, "Failed to duplicate the loop\n");
 	  return false;
 	}
 
-      free (wont_exit);
       free_original_copy_tables ();
     }
 
@@ -967,7 +964,6 @@ try_peel_loop (struct loop *loop,
   HOST_WIDE_INT npeel;
   struct loop_size size;
   int peeled_size;
-  sbitmap wont_exit;
 
   if (!flag_peel_loops || PARAM_VALUE (PARAM_MAX_PEEL_TIMES) <= 0
       || !peeled_loops)
@@ -1042,7 +1038,7 @@ try_peel_loop (struct loop *loop,
 
   /* Duplicate possibly eliminating the exits.  */
   initialize_original_copy_tables ();
-  wont_exit = sbitmap_alloc (npeel + 1);
+  auto_sbitmap wont_exit (npeel + 1);
   if (exit && niter
       && TREE_CODE (niter) == INTEGER_CST
       && wi::leu_p (npeel, wi::to_widest (niter)))
@@ -1061,10 +1057,8 @@ try_peel_loop (struct loop *loop,
 					     DLTHE_FLAG_UPDATE_FREQ))
     {
       free_original_copy_tables ();
-      free (wont_exit);
       return false;
     }
-  free (wont_exit);
   free_original_copy_tables ();
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/tree-ssa-loop-manip.c b/gcc/tree-ssa-loop-manip.c
index e87d290..f2d3492 100644
--- a/gcc/tree-ssa-loop-manip.c
+++ b/gcc/tree-ssa-loop-manip.c
@@ -1173,7 +1173,6 @@ tree_transform_and_unroll_loop (struct loop *loop, unsigned factor,
   unsigned est_niter, prob_entry, scale_unrolled, scale_rest, freq_e, freq_h;
   unsigned new_est_niter, i, prob;
   unsigned irr = loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP;
-  sbitmap wont_exit;
   auto_vec<edge> to_remove;
 
   est_niter = expected_loop_iterations (loop);
@@ -1307,14 +1306,13 @@ tree_transform_and_unroll_loop (struct loop *loop, unsigned factor,
 
   /* Unroll the loop and remove the exits in all iterations except for the
      last one.  */
-  wont_exit = sbitmap_alloc (factor);
+  auto_sbitmap wont_exit (factor);
   bitmap_ones (wont_exit);
   bitmap_clear_bit (wont_exit, factor - 1);
 
   ok = gimple_duplicate_loop_to_header_edge
 	  (loop, loop_latch_edge (loop), factor - 1,
 	   wont_exit, new_exit, &to_remove, DLTHE_FLAG_UPDATE_FREQ);
-  free (wont_exit);
   gcc_assert (ok);
 
   FOR_EACH_VEC_ELT (to_remove, i, e)
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index a5f3486..c2c7495 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -2359,7 +2359,7 @@ compute_antic (void)
   int *postorder = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
   int postorder_num = inverted_post_order_compute (postorder);
 
-  sbitmap worklist = sbitmap_alloc (last_basic_block_for_fn (cfun) + 1);
+  auto_sbitmap worklist (last_basic_block_for_fn (cfun) + 1);
   bitmap_ones (worklist);
   while (changed)
     {
@@ -2409,7 +2409,6 @@ compute_antic (void)
     }
 
   sbitmap_free (has_abnormal_preds);
-  sbitmap_free (worklist);
   free (postorder);
 }
 
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 18cf978..7c7136e 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -1458,7 +1458,6 @@ undistribute_ops_list (enum tree_code opcode,
   unsigned int length = ops->length ();
   operand_entry *oe1;
   unsigned i, j;
-  sbitmap candidates, candidates2;
   unsigned nr_candidates, nr_candidates2;
   sbitmap_iterator sbi0;
   vec<operand_entry *> *subops;
@@ -1470,7 +1469,7 @@ undistribute_ops_list (enum tree_code opcode,
     return false;
 
   /* Build a list of candidates to process.  */
-  candidates = sbitmap_alloc (length);
+  auto_sbitmap candidates (length);
   bitmap_clear (candidates);
   nr_candidates = 0;
   FOR_EACH_VEC_ELT (*ops, i, oe1)
@@ -1494,10 +1493,7 @@ undistribute_ops_list (enum tree_code opcode,
     }
 
   if (nr_candidates < 2)
-    {
-      sbitmap_free (candidates);
-      return false;
-    }
+    return false;
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
@@ -1569,7 +1565,7 @@ undistribute_ops_list (enum tree_code opcode,
     }
 
   /* Process the (operand, code) pairs in order of most occurrence.  */
-  candidates2 = sbitmap_alloc (length);
+  auto_sbitmap candidates2 (length);
   while (!cvec.is_empty ())
     {
       oecount *c = &cvec.last ();
@@ -1665,8 +1661,6 @@ undistribute_ops_list (enum tree_code opcode,
     subops[i].release ();
   free (subops);
   cvec.release ();
-  sbitmap_free (candidates);
-  sbitmap_free (candidates2);
 
   return changed;
 }
diff --git a/gcc/tree-stdarg.c b/gcc/tree-stdarg.c
index 81a380e..f72a60b 100644
--- a/gcc/tree-stdarg.c
+++ b/gcc/tree-stdarg.c
@@ -56,7 +56,6 @@ reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
   auto_vec<edge, 10> stack;
   edge e;
   edge_iterator ei;
-  sbitmap visited;
   bool ret;
 
   if (va_arg_bb == va_start_bb)
@@ -65,7 +64,7 @@ reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
   if (! dominated_by_p (CDI_DOMINATORS, va_arg_bb, va_start_bb))
     return false;
 
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
   bitmap_clear (visited);
   ret = true;
 
@@ -105,7 +104,6 @@ reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
 	}
     }
 
-  sbitmap_free (visited);
   return ret;
 }
 
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 4de8593..fb325d5 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -1274,7 +1274,6 @@ vect_attempt_slp_rearrange_stmts (slp_instance slp_instn)
 {
   unsigned int group_size = SLP_INSTANCE_GROUP_SIZE (slp_instn);
   unsigned int i, j;
-  sbitmap load_index;
   unsigned int lidx;
   slp_tree node, load;
 
@@ -1294,29 +1293,20 @@ vect_attempt_slp_rearrange_stmts (slp_instance slp_instn)
 
   /* Check that the loads in the first sequence are different and there
      are no gaps between them.  */
-  load_index = sbitmap_alloc (group_size);
+  auto_sbitmap load_index (group_size);
   bitmap_clear (load_index);
   FOR_EACH_VEC_ELT (node->load_permutation, i, lidx)
     {
       if (lidx >= group_size)
-	{
-	  sbitmap_free (load_index);
-	  return false;
-	}
+	return false;
       if (bitmap_bit_p (load_index, lidx))
-	{
-	  sbitmap_free (load_index);
-	  return false;
-	}
+	return false;
+
       bitmap_set_bit (load_index, lidx);
     }
   for (i = 0; i < group_size; i++)
     if (!bitmap_bit_p (load_index, i))
-      {
-	sbitmap_free (load_index);
-	return false;
-      }
-  sbitmap_free (load_index);
+      return false;
 
   /* This permutation is valid for reduction.  Since the order of the
      statements in the nodes is not important unless they are memory
diff --git a/gcc/var-tracking.c b/gcc/var-tracking.c
index 5d09879..9088978 100644
--- a/gcc/var-tracking.c
+++ b/gcc/var-tracking.c
@@ -6996,7 +6996,7 @@ vt_find_locations (void)
 {
   bb_heap_t *worklist = new bb_heap_t (LONG_MIN);
   bb_heap_t *pending = new bb_heap_t (LONG_MIN);
-  sbitmap visited, in_worklist, in_pending;
+  sbitmap in_worklist, in_pending;
   basic_block bb;
   edge e;
   int *bb_order;
@@ -7016,7 +7016,7 @@ vt_find_locations (void)
     bb_order[rc_order[i]] = i;
   free (rc_order);
 
-  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  auto_sbitmap visited (last_basic_block_for_fn (cfun));
   in_worklist = sbitmap_alloc (last_basic_block_for_fn (cfun));
   in_pending = sbitmap_alloc (last_basic_block_for_fn (cfun));
   bitmap_clear (in_worklist);
@@ -7185,7 +7185,6 @@ vt_find_locations (void)
   free (bb_order);
   delete worklist;
   delete pending;
-  sbitmap_free (visited);
   sbitmap_free (in_worklist);
   sbitmap_free (in_pending);