domwalk.c (walk_dominator_tree): Reorganize to non-recursive implementation.

	* domwalk.c (walk_dominator_tree): Reorganize to non-recursive
	implementation.

From-SVN: r115912

gcc/ChangeLog

+2006-08-03  Jan Hubicka  <jh@suse.cz>
+
+	* domwalk.c (walk_dominator_tree): Reorganize to non-recursive
+	implementation.
+
 2006-08-03  Dorit Nuzman  <dorit@il.ibm.com>
 
         PR tree-optimization/27770

gcc/domwalk.c

@@ -146,13 +146,20 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
   basic_block dest;
   block_stmt_iterator bsi;
   bool is_interesting;
+  basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks * 2);
+  int sp = 0;
 
+  while (true)
+    {
+      /* Don't worry about unreachable blocks.  */
+      if (EDGE_COUNT (bb->preds) > 0 || bb == ENTRY_BLOCK_PTR)
+	{
 	  /* If block BB is not interesting to the caller, then none of the
 	     callbacks that walk the statements in BB are going to be
 	     executed.  */
-  is_interesting = bb->index < 0
-		   || walk_data->interesting_blocks == NULL
-		   || TEST_BIT (walk_data->interesting_blocks, bb->index);
+	  is_interesting = walk_data->interesting_blocks == NULL
+	                   || TEST_BIT (walk_data->interesting_blocks,
+					bb->index);
 
 	  /* Callback to initialize the local data structure.  */
 	  if (walk_data->initialize_block_local_data)
@@ -176,7 +183,8 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
 	      VEC_safe_push (void_p, heap, walk_data->block_data_stack, bd);
 
 	      /* Call the initializer.  */
-      walk_data->initialize_block_local_data (walk_data, bb, recycled);
+	      walk_data->initialize_block_local_data (walk_data, bb,
+						      recycled);
 
 	    }
 
@@ -190,10 +198,12 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
 	    {
 	      if (walk_data->walk_stmts_backward)
 		for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi))
-	  (*walk_data->before_dom_children_walk_stmts) (walk_data, bb, bsi);
+		  (*walk_data->before_dom_children_walk_stmts) (walk_data, bb,
+								bsi);
 	      else
 		for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
-	  (*walk_data->before_dom_children_walk_stmts) (walk_data, bb, bsi);
+		  (*walk_data->before_dom_children_walk_stmts) (walk_data, bb,
+								bsi);
 	    }
 
 	  /* Callback for operations to execute before we have walked the
@@ -201,17 +211,23 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
 	  if (walk_data->before_dom_children_after_stmts)
 	    (*walk_data->before_dom_children_after_stmts) (walk_data, bb);
 
-  /* Recursively call ourselves on the dominator children of BB.  */
+	  /* Mark the current BB to be popped out of the recursion stack
+	     once childs are processed.  */
+	  worklist[sp++] = bb;
+	  worklist[sp++] = NULL;
+
 	  for (dest = first_dom_son (walk_data->dom_direction, bb);
-       dest;
-       dest = next_dom_son (walk_data->dom_direction, dest))
-    {
-      /* The destination block may have become unreachable, in
-	 which case there's no point in optimizing it.  */
-      if (EDGE_COUNT (dest->preds) > 0)
-	walk_dominator_tree (walk_data, dest);
+	       dest; dest = next_dom_son (walk_data->dom_direction, dest))
+	    worklist[sp++] = dest;
 	}
-
+      /* NULL is used to signalize pop operation in recursion stack.  */
+      while (sp > 0 && !worklist[sp - 1])
+	{
+	  --sp;
+	  bb = worklist[--sp];
+	  is_interesting = walk_data->interesting_blocks == NULL
+	                   || TEST_BIT (walk_data->interesting_blocks,
+				        bb->index);
 	  /* Callback for operations to execute after we have walked the
 	     dominator children, but before we walk statements.  */
 	  if (walk_data->after_dom_children_before_stmts)
@@ -222,10 +238,12 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
 	    {
 	      if (walk_data->walk_stmts_backward)
 		for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi))
-	  (*walk_data->after_dom_children_walk_stmts) (walk_data, bb, bsi);
+		  (*walk_data->after_dom_children_walk_stmts) (walk_data, bb,
+							       bsi);
 	      else
 		for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
-	  (*walk_data->after_dom_children_walk_stmts) (walk_data, bb, bsi);
+		  (*walk_data->after_dom_children_walk_stmts) (walk_data, bb,
+							       bsi);
 	    }
 
 	  /* Callback for operations to execute after we have walked the
@@ -235,12 +253,18 @@ walk_dominator_tree (struct dom_walk_data *walk_data, basic_block bb)
 
 	  if (walk_data->initialize_block_local_data)
 	    {
+	      /* And finally pop the record off the block local data stack.  */
+	      bd = VEC_pop (void_p, walk_data->block_data_stack);
 	      /* And save the block data so that we can re-use it.  */
 	      VEC_safe_push (void_p, heap, walk_data->free_block_data, bd);
-
-      /* And finally pop the record off the block local data stack.  */
-      VEC_pop (void_p, walk_data->block_data_stack);
 	    }
+	}
+      if (sp)
+	bb = worklist[--sp];
+      else
+	break;
+    }
+  free (worklist);
 }
 
 void