[PATCH] Remove unused VAR_DECLs from dump files

[Richard Guenther <rguenther at suse dot de>]

After trying to remove these from our datastructures for real
with no success, this is the simpler approach of just not cluttering
the dump-files with them.

It still saves about half of the space for a full -fdump-tree-all
compile of tramp3d and shrinks single dump files down to about
20% of their size.

Bootstrapped on x86_64-unknown-linux-gnu, checking in progress.

Ok for mainline, even at stage3?

Thanks,
Richard.

:ADDPATCH:

2005-08-03  Richard Guenther  <rguenther@suse.de>

	* tree-cfg.c (mark_used_vars): New function.
	(dump_function_to_file): Dump only used VAR_DECLs.

Index: tree-cfg.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-cfg.c,v
retrieving revision 2.212
diff -c -3 -p -r2.212 tree-cfg.c
*** tree-cfg.c	28 Jul 2005 07:41:22 -0000	2.212
--- tree-cfg.c	3 Aug 2005 16:12:01 -0000
*************** tree_duplicate_sese_region (edge entry, 
*** 4372,4377 ****
--- 4372,4397 ----
  }
  
  
+ static tree
+ mark_used_vars (tree *tp, int *walk_subtrees, void *used_vars_)
+ {
+   bitmap *used_vars = (bitmap *)used_vars_;
+ 
+   if (walk_subtrees
+       && IS_TYPE_OR_DECL_P (*tp))
+     *walk_subtrees = 0;
+ 
+   if (!SSA_VAR_P (*tp))
+     return NULL_TREE;
+ 
+   if (TREE_CODE (*tp) == SSA_NAME)
+     bitmap_set_bit (*used_vars, DECL_UID (SSA_NAME_VAR (*tp)));
+   else
+     bitmap_set_bit (*used_vars, DECL_UID (*tp));
+ 
+   return NULL_TREE;
+ }
+ 
  /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h)  */
  
  void
*************** dump_function_to_file (tree fn, FILE *fi
*** 4406,4423 ****
--- 4426,4467 ----
       BIND_EXPRs, so display them separately.  */
    if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
      {
+       bitmap used_vars = BITMAP_ALLOC (NULL);
        ignore_topmost_bind = true;
  
+       /* Record vars we'll use dumping the functions tree.  */
+       FOR_EACH_BB (bb)
+ 	{
+ 	  block_stmt_iterator bsi;
+ 	  for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ 	    walk_tree (bsi_stmt_ptr (bsi), mark_used_vars,
+ 		       &used_vars, NULL);
+ 	}
+       for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
+ 	{
+ 	  var = TREE_VALUE (vars);
+ 	  if (TREE_CODE (var) == VAR_DECL
+ 	      && DECL_INITIAL (var)
+ 	      && bitmap_bit_p (used_vars, DECL_UID (var)))
+ 	    walk_tree (&DECL_INITIAL (var), mark_used_vars,
+ 		       &used_vars, NULL);
+ 	}
+ 
+       /* Dump used vars.  */
        fprintf (file, "{\n");
        for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
  	{
  	  var = TREE_VALUE (vars);
+ 	  if (!bitmap_bit_p (used_vars, DECL_UID (var)))
+             continue;
  
  	  print_generic_decl (file, var, flags);
  	  fprintf (file, "\n");
  
  	  any_var = true;
  	}
+ 
+       BITMAP_FREE (used_vars);
      }
  
    if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)