Re: CFG transparent expansion 4

[Jan Hubicka <jh at suse dot cz>]

> On Thu, Jun 17, 2004 at 07:28:29PM +0200, Jan Hubicka wrote:
> > + 	    /* label_to_block might put undefined labels into the first basic
> > + 	       block.  */
> > + 	    if (!label_for_bb[true_bb->index])
> > + 	      label_for_bb[true_bb->index] = GOTO_DESTINATION (true_branch);
> 
> How about pulling out this into a new function, cdl_label_to_block
> or something?  You've got 4 or 5 potential uses...

Hi,
this is the patch I am just testing.  It seems to be easier to pull it
all together asthere shall be no more users (after this pass, all labels
are defined)

OK, assuming it passes i686-pc-gnu-linux?

2004-06-17  Jan Hubicka  <jh@suse.cz>
	* tree-cfg.c (label_to_block): Invent the label destination for
	undefined labels.
	(main_block_label): New function.
	(cleanup_dead_labels): Update table in the case label_to_block added
	new label.
Index: tree-cfg.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-cfg.c,v
retrieving revision 2.14
diff -c -3 -p -r2.14 tree-cfg.c
*** tree-cfg.c	17 Jun 2004 18:13:11 -0000	2.14
--- tree-cfg.c	17 Jun 2004 20:52:15 -0000
*************** make_switch_expr_edges (basic_block bb)
*** 647,653 ****
  basic_block
  label_to_block (tree dest)
  {
!   return VARRAY_BB (label_to_block_map, LABEL_DECL_UID (dest));
  }
  
  
--- 647,667 ----
  basic_block
  label_to_block (tree dest)
  {
!   int uid = LABEL_DECL_UID (dest);
! 
!   /* We would die hard when faced by undefined label.  Emit label to
!      very first basic block.  This will hopefully make even the dataflow
!      and undefined variable warnings quite right.  */
!   if ((errorcount || sorrycount) && uid < 0)
!     {
!       block_stmt_iterator bsi = bsi_start (BASIC_BLOCK (0));
!       tree stmt;
! 
!       stmt = build1 (LABEL_EXPR, void_type_node, dest);
!       bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
!       uid = LABEL_DECL_UID (dest);
!     }
!   return VARRAY_BB (label_to_block_map, uid);
  }
  
  
*************** update_eh_label (struct eh_region *regio
*** 784,789 ****
--- 798,815 ----
      }
  }
  
+ /* Given LABEL return the first label in the same basic block.  */
+ static tree
+ main_block_label (tree label)
+ {
+   basic_block bb = label_to_block (label);
+ 
+   /* label_to_block possibly inserted undefined label into the chain.  */
+   if (!label_for_bb[bb->index])
+     label_for_bb[bb->index] = label;
+   return label_for_bb[bb->index];
+ }
+ 
  /* Cleanup redundant labels.  This is a three-steo process:
       1) Find the leading label for each block.
       2) Redirect all references to labels to the leading labels.
*************** cleanup_dead_labels (void)
*** 843,857 ****
  	case COND_EXPR:
  	  {
  	    tree true_branch, false_branch;
- 	    basic_block true_bb, false_bb;
  
  	    true_branch = COND_EXPR_THEN (stmt);
  	    false_branch = COND_EXPR_ELSE (stmt);
- 	    true_bb = label_to_block (GOTO_DESTINATION (true_branch));
- 	    false_bb = label_to_block (GOTO_DESTINATION (false_branch));
  
! 	    GOTO_DESTINATION (true_branch) = label_for_bb[true_bb->index];
! 	    GOTO_DESTINATION (false_branch) = label_for_bb[false_bb->index];
  
  	    break;
  	  }
--- 869,882 ----
  	case COND_EXPR:
  	  {
  	    tree true_branch, false_branch;
  
  	    true_branch = COND_EXPR_THEN (stmt);
  	    false_branch = COND_EXPR_ELSE (stmt);
  
! 	    GOTO_DESTINATION (true_branch)
! 	      = main_block_label (GOTO_DESTINATION (true_branch));
! 	    GOTO_DESTINATION (false_branch)
! 	      = main_block_label (GOTO_DESTINATION (false_branch));
  
  	    break;
  	  }
*************** cleanup_dead_labels (void)
*** 864,875 ****
    
  	    /* Replace all destination labels.  */
  	    for (i = 0; i < n; ++i)
! 	      {
! 		tree label = CASE_LABEL (TREE_VEC_ELT (vec, i));
! 
! 		CASE_LABEL (TREE_VEC_ELT (vec, i)) =
! 		  label_for_bb[label_to_block (label)->index];
! 	      }
    
  	    break;
  	  }
--- 889,896 ----
    
  	    /* Replace all destination labels.  */
  	    for (i = 0; i < n; ++i)
! 	      CASE_LABEL (TREE_VEC_ELT (vec, i))
! 		= main_block_label (CASE_LABEL (TREE_VEC_ELT (vec, i)));
    
  	    break;
  	  }
*************** cleanup_dead_labels (void)
*** 877,889 ****
  	/* We have to handle GOTO_EXPRs until they're removed, and we don't
  	   remove them until after we've created the CFG edges.  */
  	case GOTO_EXPR:
! 	  {
! 	    tree label = GOTO_DESTINATION (stmt);
! 	    if (! computed_goto_p (stmt))
! 	      GOTO_DESTINATION (stmt) =
! 		label_for_bb[label_to_block (label)->index];
! 	    break;
! 	  }
  
  	default:
  	  break;
--- 898,909 ----
  	/* We have to handle GOTO_EXPRs until they're removed, and we don't
  	   remove them until after we've created the CFG edges.  */
  	case GOTO_EXPR:
!           if (! computed_goto_p (stmt))
! 	    {
! 	      GOTO_DESTINATION (stmt)
! 		= main_block_label (GOTO_DESTINATION (stmt));
! 	      break;
! 	    }
  
  	default:
  	  break;