1 files changed, 10 insertions, 8 deletions
diff --git a/src/cairo-skiplist.c b/src/cairo-skiplist.c
index b08453b0..d03a6bfc 100644
--- a/src/cairo-skiplist.c
+++ b/src/cairo-skiplist.c
@@ -91,20 +91,22 @@ _cairo_skip_list_fini (cairo_skip_list_t *list)
 static int
 random_level (void)
 {
-    int	level = 0;
     /* tricky bit -- each bit is '1' 75% of the time.
      * This works because we only use the lower MAX_LEVEL
      * bits, and MAX_LEVEL < 16 */
     uint32_t bits = hars_petruska_f54_1_random ();
-    bits |= bits >> 16;
-
-    while (++level < MAX_LEVEL)
-    {
-	if (bits & 1)
-	    break;
+#if HAVE_FFS
+    return ffs (-(1<<MAX_LEVEL) | bits | bits >> 16);
+#else
+    int level = 1;
+
+    bits |= -(1<<MAX_LEVEL) | bits >> 16;
+    while ((bits & 1) == 0) {
+	level++;
 	bits >>= 1;
     }
     return level;
+#endif
 }
 
 static void *
@@ -181,7 +183,7 @@ _cairo_skip_list_insert (cairo_skip_list_t *list, void *data, int unique)
     }
 
     data_and_elt = alloc_node_for_level (list, level);
-    if (data_and_elt == NULL) {
+    if (unlikely (data_and_elt == NULL)) {
 	_cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
 	return NULL;
     }