diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 2a9b21681226..24dc95819b6f 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2005-05-27  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/21614
+	* typeck.c (get_member_function_from_ptrfunc): Do not attempt
+	conversions to base classes of incomplete types.
+
 2005-05-27  Ian Lance Taylor  <ian@airs.com>
 
 	* semantics.c (add_stmt): Add C++ frontend specific version.
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 464b8efd3fa2..73bb514f4992 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -2346,14 +2346,23 @@ get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function)
 	  gcc_unreachable ();
 	}
 
-      /* Convert down to the right base before using the instance.  First
-         use the type...  */
+      /* Convert down to the right base before using the instance.  A
+	 special case is that in a pointer to member of class C, C may
+	 be incomplete.  In that case, the function will of course be
+	 a member of C, and no conversion is required.  In fact,
+	 lookup_base will fail in that case, because incomplete
+	 classes do not have BINFOs.  */ 
       basetype = TYPE_METHOD_BASETYPE (TREE_TYPE (fntype));
-      basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)),
-			      basetype, ba_check, NULL);
-      instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 1);
-      if (instance_ptr == error_mark_node)
-	return error_mark_node;
+      if (!same_type_ignoring_top_level_qualifiers_p 
+	  (basetype, TREE_TYPE (TREE_TYPE (instance_ptr))))
+	{
+	  basetype = lookup_base (TREE_TYPE (TREE_TYPE (instance_ptr)),
+				  basetype, ba_check, NULL);
+	  instance_ptr = build_base_path (PLUS_EXPR, instance_ptr, basetype, 
+					  1);
+	  if (instance_ptr == error_mark_node)
+	    return error_mark_node;
+	}
       /* ...and then the delta in the PMF.  */
       instance_ptr = build2 (PLUS_EXPR, TREE_TYPE (instance_ptr),
 			     instance_ptr, delta);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index efeae615a679..a6d54b3a4fca 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2005-05-27  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/21614
+	* g++.dg/expr/ptrmem6.C: New test.
+	* g++.dg/expr/ptrmem6a.C: Likewise.
+
 2005-05-27  Kazu Hirata  <kazu@cs.umass.edu>
 
 	PR tree-optimization/21658
diff --git a/gcc/testsuite/g++.dg/expr/ptrmem6.C b/gcc/testsuite/g++.dg/expr/ptrmem6.C
new file mode 100644
index 000000000000..0c75385fbd0f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/expr/ptrmem6.C
@@ -0,0 +1,12 @@
+// PR C++/21614
+// { dg-additional-sources "ptrmem6a.C" }
+// { dg-do run }
+
+extern struct Z *p; 
+extern int (Z::*m) (); 
+ 
+int main () { 
+  if ((p->*m)() == 7)
+    return 0;
+  return 1;
+}
diff --git a/gcc/testsuite/g++.dg/expr/ptrmem6a.C b/gcc/testsuite/g++.dg/expr/ptrmem6a.C
new file mode 100644
index 000000000000..8dad81c5889a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/expr/ptrmem6a.C
@@ -0,0 +1,9 @@
+struct Z {
+  int f();
+};
+
+int Z::f() { return 7; }
+
+struct Z z;
+int (Z::*m)() = &Z::f;
+struct Z*p = &z;