re PR tree-optimization/18601 (tree cfglceanup is slow)

	PR tree-optimization/18601
	* tree-cfg.c (thread_jumps, thread_jumps_from_bb): Removed.
	(tree_forwarder_block_p): Do not consider blocks that are its own
	successors forwarders.
	(cleanup_forwarder_blocks, remove_forwarder_block): New functions.
	(cleanup_tree_cfg): Use cleanup_forwarder_blocks instead of
	thread_jumps.
	* tree-flow.h (bb_ann_d): Remove forwardable.

Co-Authored-By: Kazu Hirata <kazu@cs.umass.edu>

From-SVN: r91787

gcc/ChangeLog

+2004-12-06  Zdenek Dvorak  <dvorakz@suse.cz>
+	    Kazu Hirata  <kazu@cs.umass.edu>
+
+	PR tree-optimization/18601
+	* tree-cfg.c (thread_jumps, thread_jumps_from_bb): Removed.
+	(tree_forwarder_block_p): Do not consider blocks that are its own
+	successors forwarders.
+	(cleanup_forwarder_blocks, remove_forwarder_block): New functions.
+	(cleanup_tree_cfg): Use cleanup_forwarder_blocks instead of
+	thread_jumps.
+	* tree-flow.h (bb_ann_d): Remove forwardable.
+
 2004-12-06  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* expr.c (expand_expr_real_1): Remove an "if" whose condition

gcc/tree-flow.h

@@ -345,10 +345,6 @@ struct bb_ann_d GTY(())
   /* Chain of PHI nodes for this block.  */
   tree phi_nodes;
 
-  /* Nonzero if this block is forwardable during cfg cleanups.  This is also
-     used to detect loops during cfg cleanups.  */
-  unsigned forwardable: 1;
-
   /* Nonzero if this block contains an escape point (see is_escape_site).  */
   unsigned has_escape_site : 1;