bitmap.c (bitmap_find_bit): Speed up by traversing from head->first if that seems profitable.

	* bitmap.c (bitmap_find_bit): Speed up by traversing from
	head->first if that seems profitable.

From-SVN: r91335

gcc/ChangeLog

@@ -3,6 +3,9 @@
 	* cfgrtl.c (try_redirect_by_replacing_jump): Speed up the
 	check that tests if all edges go to the same destination.
 
+	* bitmap.c (bitmap_find_bit): Speed up by traversing from
+	head->first if that seems profitable.
+
 2004-11-25  Jeff Law  <law@redhat.com>
 
 	* timevar.def (TV_TREE_LOOP_INIT, TV_TREE_LOOP_FINI): New timevars.

gcc/bitmap.c

@@ -401,14 +401,26 @@ bitmap_find_bit (bitmap head, unsigned int bit)
       || head->indx == indx)
     return head->current;
 
-  if (head->indx > indx)
+  if (head->indx < indx)
+    /* INDX is beyond head->indx.  Search from head->current
+       forward.  */
+    for (element = head->current;
+	 element->next != 0 && element->indx < indx;
+	 element = element->next)
+      ;
+
+  else if (head->indx / 2 < indx)
+    /* INDX is less than head->indx and closer to head->indx than to
+       0.  Search from head->current backward.  */
     for (element = head->current;
 	 element->prev != 0 && element->indx > indx;
 	 element = element->prev)
       ;
 
   else
-    for (element = head->current;
+    /* INDX is less than head->indx and closer to 0 than to
+       head->indx.  Search from head->first forward.  */
+    for (element = head->first;
 	 element->next != 0 && element->indx < indx;
 	 element = element->next)
       ;