g_value_set_pointer: reduce calls to g_type_value_table_peek

Trims off 8% cpu time from calling this method.

1 files changed, 10 insertions, 6 deletions

diff --git a/gobject/gvalue.c b/gobject/gvalue.c
index 46a03d535..1315fd8d8 100644
--- a/gobject/gvalue.c
+++ b/gobject/gvalue.c
@@ -350,18 +350,22 @@ g_value_set_instance (GValue  *value,
   GTypeValueTable *value_table;
   GTypeCValue cvalue;
   gchar *error_msg;
-  
+
   g_return_if_fail (G_IS_VALUE (value));
+  g_type = G_VALUE_TYPE (value);
+  value_table = g_type_value_table_peek (g_type);
+  g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
+
   if (instance)
     {
       g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
-      g_return_if_fail (VALUE_TYPE_COMPATIBLE (G_TYPE_FROM_INSTANCE (instance), G_VALUE_TYPE (value)));
+      /* This is the expanded value of VALUE_TYPE_COMPATIBLE, but re-using the value-table
+       * we have already queried force the value. This avoids calling
+       * g_value_table_peek() twice. Saves 8% cpu time on calling this method */
+      g_return_if_fail (g_type_is_a (G_TYPE_FROM_INSTANCE(instance), g_type) &&
+			value_table == g_type_value_table_peek (G_TYPE_FROM_INSTANCE (instance)));
     }
   
-  g_type = G_VALUE_TYPE (value);
-  value_table = g_type_value_table_peek (g_type);
-  
-  g_return_if_fail (strcmp (value_table->collect_format, "p") == 0);
   
   memset (&cvalue, 0, sizeof (cvalue));
   cvalue.v_pointer = instance;