except.c (for_each_eh_region): New function.

	* except.c (for_each_eh_region): New function.
	* except.h (for_each_eh_region): Add a prototype for it.
	* tree-cfg.c (update_eh_labels): New function, callback for
	for_each_eh_region.
	(label_for_bb): Make global static, unfortunately.
	(cleanup_dead_labels): Also update label references for
	exception regions.

From-SVN: r82622

1 files changed, 31 insertions, 3 deletions

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 21277d8..d6823cb 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -762,13 +762,38 @@ cleanup_tree_cfg (void)
 }
 
 
-/* Cleanup useless labels from the flow graph.  */
+/* Cleanup useless labels in basic blocks.  This is something we wish
+   to do early because it allows us to group case labels before creating
+   the edges for the CFG, and it speeds up block statement iterators in
+   all passes later on.
+   We only run this pass once, running it more than once is probably not
+   profitable.  */
+
+/* A map from basic block index to the leading label of that block.  */
+static tree *label_for_bb;
+
+/* Callback for for_each_eh_region.  Helper for cleanup_dead_labels.  */
+static void
+update_eh_label (struct eh_region *region)
+{
+  tree old_label = get_eh_region_tree_label (region);
+  if (old_label)
+    {
+      tree new_label = label_for_bb[label_to_block (old_label)->index];
+      set_eh_region_tree_label (region, new_label);
+    }
+}
+
+/* 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.
+     3) Cleanup all useless labels.  */
 
 static void
 cleanup_dead_labels (void)
 {
   basic_block bb;
-  tree *label_for_bb = xcalloc (last_basic_block, sizeof (tree));
+  label_for_bb = xcalloc (last_basic_block, sizeof (tree));
 
   /* Find a suitable label for each block.  We use the first user-defined
      label is there is one, or otherwise just the first label we see.  */
@@ -805,7 +830,8 @@ cleanup_dead_labels (void)
 	}
     }
 
-  /* Now redirect all jumps/branches to the selected label for each block.  */
+  /* Now redirect all jumps/branches to the selected label.
+     First do so for each block ending in a control statement.  */
   FOR_EACH_BB (bb)
     {
       tree stmt = last_stmt (bb);
@@ -864,6 +890,8 @@ cleanup_dead_labels (void)
       }
     }
 
+  for_each_eh_region (update_eh_label);
+
   /* Finally, purge dead labels.  All user-defined labels and labels that
      can be the target of non-local gotos are preserved.  */
   FOR_EACH_BB (bb)