tree-cfg.c (hashtab.h): Include.

	* tree-cfg.c (hashtab.h): Include.
	(struct edge_to_case_leader_elt): New structure.
	(edge_to_case_leader): New.
	(edge_to_case_leader_hash): New hashtable hasing function.
	(edge_to_case_leader_eq): New hashtable equality function.
	(record_switch_edge): New function.
	(get_case_leader_for_edge, get_case_leader_for_edge): New functions.
	(make_switch_expr_edges): Build the edge-to-case-leader
	hash table.  Tear down the hash table when we're done.
	(cleanup_dead_labels): Use CASE_LEADER_OR_LABEL instead of
	CASE_LABEL.
	(tree_node_can_be_shared): Allow sharing of CASE_LABEL_EXPR nodes.
	(tree_redirect_edge_and_branch, case SWITCH_EXPR): Update
	to use new concept of case leaders to reduce overhead of
	redirecting outgoing edges from switch statements.
	* tree.c (get_case_label): New function.
	* tree.h (CASE_LABEL): Define in terms of get_case_label.
	(CASE_LEADER_OR_LABEL): Define.

From-SVN: r90570

1 files changed, 13 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 97adffa..8774107 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -6061,4 +6061,17 @@ signed_type_for (tree type)
   return lang_hooks.types.signed_type (type);
 }
 
+/* Return the LABEL_DECL associated with T, which must be a 
+   CASE_LABEL_EXPR.  This will walk through any CASE_LABEL_EXPRs
+   appearing in operand 2 until it finds a CASE_LABEL_EXPR with
+   a LABEL_DECL in operand 2.  */
+
+tree
+get_case_label (tree t)
+{
+  while (TREE_CODE (CASE_LEADER_OR_LABEL (t)) == CASE_LABEL_EXPR)
+    t = CASE_LEADER_OR_LABEL (t);
+  return CASE_LEADER_OR_LABEL (t);
+}
+
 #include "gt-tree.h"