diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2cc045ba7e2..1324aeb83b8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2010-12-24  Nicola Pero  <nicola.pero@meta-innovation.com>
+
+	* obj-c.dg/gnu-api-2-class.m: Test that class_conformsToProtocol()
+	does not check the superclasses.
+	* obj-c++.dg/gnu-api-2-class.mm: Same change.	
+
 2010-12-24  Alexander Monakov  <amonakov@ispras.ru>
 
 	PR rtl-optimization/47036
diff --git a/gcc/testsuite/obj-c++.dg/gnu-api-2-class.mm b/gcc/testsuite/obj-c++.dg/gnu-api-2-class.mm
index da25663d171..b86396f2144 100644
--- a/gcc/testsuite/obj-c++.dg/gnu-api-2-class.mm
+++ b/gcc/testsuite/obj-c++.dg/gnu-api-2-class.mm
@@ -42,6 +42,12 @@
 - (id) variable { return variable_ivar; }
 @end
 
+@interface MyOtherSubClass : MySubClass
+@end
+
+@implementation MyOtherSubClass
+@end
+
 @interface DifferentClass : MyRootClass
 - (id) myClass;
 - (id) self;
@@ -188,6 +194,11 @@ int main ()
 
     if (!class_conformsToProtocol (objc_getClass ("MySubClass"), @protocol (MyProtocol)))
       abort ();
+
+    /* Test that class_conformsToProtocol checks the class, but not
+       superclasses.  */
+    if (class_conformsToProtocol (objc_getClass ("MyOtherSubClass"), @protocol (MyProtocol)))
+      abort ();
   }
 
   std::cout << "Testing class_copyIvarList ()...\n";
diff --git a/gcc/testsuite/objc.dg/gnu-api-2-class.m b/gcc/testsuite/objc.dg/gnu-api-2-class.m
index d38d9c253dc..ff0425966cd 100644
--- a/gcc/testsuite/objc.dg/gnu-api-2-class.m
+++ b/gcc/testsuite/objc.dg/gnu-api-2-class.m
@@ -42,6 +42,12 @@
 - (id) variable { return variable_ivar; }
 @end
 
+@interface MyOtherSubClass : MySubClass
+@end
+
+@implementation MyOtherSubClass
+@end
+
 @interface DifferentClass : MyRootClass
 - (id) myClass;
 - (id) self;
@@ -188,6 +194,11 @@ int main(int argc, void **args)
 
     if (!class_conformsToProtocol (objc_getClass ("MySubClass"), @protocol (MyProtocol)))
       abort ();
+
+    /* Test that class_conformsToProtocol checks the class, but not
+       superclasses.  */
+    if (class_conformsToProtocol (objc_getClass ("MyOtherSubClass"), @protocol (MyProtocol)))
+      abort ();
   }
 
   printf ("Testing class_copyIvarList ()...\n");
diff --git a/libobjc/ChangeLog b/libobjc/ChangeLog
index fbeaf3fa571..78112bdecfe 100644
--- a/libobjc/ChangeLog
+++ b/libobjc/ChangeLog
@@ -1,3 +1,8 @@
+2010-12-24  Nicola Pero  <nicola.pero@meta-innovation.com>
+
+	* objc/runtime.h (class_conformsToProtocol,
+	class_copyProtocolList): Updated documentation.
+
 2010-12-23  Nicola Pero  <nicola.pero@meta-innovation.com>
 
 	* init.c (create_tree_of_subclasses_inherited_from): Updated
diff --git a/libobjc/objc/runtime.h b/libobjc/objc/runtime.h
index 8d380156e41..7ad46dcc6fd 100644
--- a/libobjc/objc/runtime.h
+++ b/libobjc/objc/runtime.h
@@ -768,7 +768,11 @@ objc_EXPORT Protocol **objc_copyProtocolList (unsigned int *numberOfReturnedProt
 objc_EXPORT BOOL class_addProtocol (Class class_, Protocol *protocol);
 
 /* Return YES if the class 'class_' conforms to Protocol 'protocol',
-   and NO if not.  */
+   and NO if not.  This function does not check superclasses; if you
+   want to check for superclasses (in the way that [NSObject
+   +conformsToProtocol:] does) you need to iterate over the class
+   hierarchy using class_getSuperclass(), and call
+   class_conformsToProtocol() for each of them.  */
 objc_EXPORT BOOL class_conformsToProtocol (Class class_, Protocol *protocol);
 
 /* Return all the protocols that the class conforms to.  The return
@@ -777,7 +781,9 @@ objc_EXPORT BOOL class_conformsToProtocol (Class class_, Protocol *protocol);
    class.  It does not include protocols adopted by superclasses.  The
    list is terminated by NULL.  Optionally, if you pass a non-NULL
    'numberOfReturnedProtocols' pointer, the unsigned int that it
-   points to will be filled with the number of protocols returned.  */
+   points to will be filled with the number of protocols returned.
+   This function does not return protocols that superclasses conform
+   to.  */
 objc_EXPORT Protocol **class_copyProtocolList (Class class_, unsigned int *numberOfReturnedProtocols);
 
 /* Return YES if protocol 'protocol' conforms to protocol