2009-05-08 Tobias Burnus <burnus@net-b.de>

[pf3gnuchains/gcc-fork.git] / gcc / gimplify.c

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 0909d31..0c33dab 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1604,20 +1604,63 @@ gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
        }
       len = i;
 
+      if (!VEC_empty (tree, labels))
+       sort_case_labels (labels);
+
       if (!default_case)
        {
-         gimple new_default;
+         tree type = TREE_TYPE (switch_expr);
 
          /* If the switch has no default label, add one, so that we jump
-            around the switch body.  */
-         default_case = build3 (CASE_LABEL_EXPR, void_type_node, NULL_TREE,
-                                NULL_TREE, create_artificial_label ());
-         new_default = gimple_build_label (CASE_LABEL (default_case));
-         gimplify_seq_add_stmt (&switch_body_seq, new_default);
-       }
+            around the switch body.  If the labels already cover the whole
+            range of type, add the default label pointing to one of the
+            existing labels.  */
+         if (type == void_type_node)
+           type = TREE_TYPE (SWITCH_COND (switch_expr));
+         if (len
+             && INTEGRAL_TYPE_P (type)
+             && TYPE_MIN_VALUE (type)
+             && TYPE_MAX_VALUE (type)
+             && tree_int_cst_equal (CASE_LOW (VEC_index (tree, labels, 0)),
+                                    TYPE_MIN_VALUE (type)))
+           {
+             tree low, high = CASE_HIGH (VEC_index (tree, labels, len - 1));
+             if (!high)
+               high = CASE_LOW (VEC_index (tree, labels, len - 1));
+             if (tree_int_cst_equal (high, TYPE_MAX_VALUE (type)))
+               {
+                 for (i = 1; i < len; i++)
+                   {
+                     high = CASE_LOW (VEC_index (tree, labels, i));
+                     low = CASE_HIGH (VEC_index (tree, labels, i - 1));
+                     if (!low)
+                       low = CASE_LOW (VEC_index (tree, labels, i - 1));
+                     if ((TREE_INT_CST_LOW (low) + 1
+                          != TREE_INT_CST_LOW (high))
+                         || (TREE_INT_CST_HIGH (low)
+                             + (TREE_INT_CST_LOW (high) == 0)
+                             != TREE_INT_CST_HIGH (high)))
+                       break;
+                   }
+                 if (i == len)
+                   default_case = build3 (CASE_LABEL_EXPR, void_type_node,
+                                          NULL_TREE, NULL_TREE,
+                                          CASE_LABEL (VEC_index (tree,
+                                                                 labels, 0)));
+               }
+           }
 
-      if (!VEC_empty (tree, labels))
-       sort_case_labels (labels);
+         if (!default_case)
+           {
+             gimple new_default;
+
+             default_case = build3 (CASE_LABEL_EXPR, void_type_node,
+                                    NULL_TREE, NULL_TREE,
+                                    create_artificial_label ());
+             new_default = gimple_build_label (CASE_LABEL (default_case));
+             gimplify_seq_add_stmt (&switch_body_seq, new_default);
+           }
+       }
 
       gimple_switch = gimple_build_switch_vec (SWITCH_COND (switch_expr), 
                                                default_case, labels);