[glib/gtype-speedups: 1/2] gtype: Speed up g_type_is_a

[Matthias Clasen <matthiasc src gnome org>]

commit 22f51b87a28b308be4bd0d462b7a3a0e9e7d1790
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu May 19 21:06:18 2022 -0400

    gtype: Speed up g_type_is_a
    
    As noticed by Christian Hergert: We can reduce
    some overhead by checking for exact type
    equality first. According to Christian, around
    3% of g_type_is_a calls are exact equalities.

 gobject/gtype.c | 4 ++--
 gobject/gtype.h | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/gobject/gtype.c b/gobject/gtype.c
index c08f11345d..ded0acee28 100644
--- a/gobject/gtype.c
+++ b/gobject/gtype.c
@@ -3577,8 +3577,8 @@ type_node_conforms_to_U (TypeNode *node,
  * Returns: %TRUE if @type is a @is_a_type
  */
 gboolean
-g_type_is_a (GType type,
-            GType iface_type)
+(g_type_is_a) (GType type,
+              GType iface_type)
 {
   TypeNode *node, *iface_node;
   gboolean is_a;
diff --git a/gobject/gtype.h b/gobject/gtype.h
index f2620f83bf..66cac1fc58 100644
--- a/gobject/gtype.h
+++ b/gobject/gtype.h
@@ -728,6 +728,10 @@ GType                 g_type_next_base               (GType            leaf_type
 GLIB_AVAILABLE_IN_ALL
 gboolean              g_type_is_a                    (GType            type,
                                                      GType            is_a_type);
+
+/* Hoist exact GType comparisons into the caller */
+#define g_type_is_a(a,b) ((a) == (b) || (g_type_is_a) ((a), (b)))
+
 GLIB_AVAILABLE_IN_ALL
 gpointer              g_type_class_ref               (GType            type);
 GLIB_AVAILABLE_IN_ALL