diff --git a/glib/gmacros.h b/glib/gmacros.h
index 9b057ce..22edb2e 100644
--- a/glib/gmacros.h
+++ b/glib/gmacros.h
@@ -354,8 +354,8 @@
       _g_boolean_var_ = 0;                      \
    _g_boolean_var_;                             \
 })
-#define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR(expr), 1))
-#define G_UNLIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR(expr), 0))
+#define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 1))
+#define G_UNLIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 0))
 #else
 #define G_LIKELY(expr) (expr)
 #define G_UNLIKELY(expr) (expr)
