* 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.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@90570 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 12 insertions, 3 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index 105966a262c..e79470001cd 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1229,9 +1229,17 @@ struct tree_vec GTY(())
 
 /* CASE_LABEL_EXPR accessors. These give access to the high and low values
    of a case label, respectively.  */
-#define CASE_LOW(NODE)          TREE_OPERAND ((NODE), 0)
-#define CASE_HIGH(NODE)         TREE_OPERAND ((NODE), 1)
-#define CASE_LABEL(NODE)        TREE_OPERAND ((NODE), 2)
+#define CASE_LOW(NODE)          	TREE_OPERAND ((NODE), 0)
+#define CASE_HIGH(NODE)         	TREE_OPERAND ((NODE), 1)
+
+/* Operand 2 has two uses, it may either be a LABEL_DECL node or a
+   another CASE_LABEL_EXPR node.  This accessor gets direct access
+   to that operand.  Use it when you want to assign a value to
+   operand 2 or when you want to conditionalalize actions based on
+   whether operand 2 is a LABEL_DELC or CASE_LABEL_EXPR.  */
+#define CASE_LEADER_OR_LABEL(NODE)	TREE_OPERAND ((NODE), 2)
+
+#define CASE_LABEL(NODE) get_case_label (NODE)
 
 /* The operands of a BIND_EXPR.  */
 #define BIND_EXPR_VARS(NODE) (TREE_OPERAND (BIND_EXPR_CHECK (NODE), 0))
@@ -3455,6 +3463,7 @@ extern void change_decl_assembler_name (tree, tree);
 extern int type_num_arguments (tree);
 extern bool associative_tree_code (enum tree_code);
 extern bool commutative_tree_code (enum tree_code);
+extern tree get_case_label (tree);
 
 
 /* In stmt.c */