diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6f290053f278..5d70567db7cc 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2005-05-27  Nathan Sidwell  <nathan@codesourcery.com>
 
+	PR c++/21455
+	* typeck.c (get_delta_difference): Cope with incomplete but equal
+	classes.  Reorder if.
+
 	PR c++/21681
 	* parser.c (cp_parser_late_parsing_for_member): Disable access
 	checking for template functions.
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 8bd101295fd4..92bbc1e071c2 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -5523,7 +5523,6 @@ get_delta_difference (tree from, tree to,
 		      bool c_cast_p)
 {
   tree binfo;
-  tree virt_binfo;
   base_kind kind;
   tree result;
 
@@ -5532,36 +5531,14 @@ get_delta_difference (tree from, tree to,
   binfo = lookup_base (to, from, c_cast_p ? ba_unique : ba_check, &kind);
   if (kind == bk_inaccessible || kind == bk_ambig)
     error ("   in pointer to member function conversion");
-  else if (!binfo)
+  else if (binfo)
     {
-      if (!allow_inverse_p)
-	{
-	  error_not_base_type (from, to);
-	  error ("   in pointer to member conversion");
-	}
-      else
-	{
-	  binfo = lookup_base (from, to, c_cast_p ? ba_unique : ba_check, 
-			       &kind);
-	  if (binfo)
-	    {
-	      virt_binfo = binfo_from_vbase (binfo);
-	      if (virt_binfo)
-		/* This is a reinterpret cast, we choose to do nothing.  */
-		warning (0, "pointer to member cast via virtual base %qT",
-			 BINFO_TYPE (virt_binfo));
-	      else
-		result = size_diffop (size_zero_node, BINFO_OFFSET (binfo));
-	    }
-	}
-    }
-  else
-    {
-      virt_binfo = binfo_from_vbase (binfo);
-      if (!virt_binfo)
+      if (kind != bk_via_virtual)
 	result = BINFO_OFFSET (binfo);
       else
 	{
+	  tree virt_binfo = binfo_from_vbase (binfo);
+	  
 	  /* This is a reinterpret cast, we choose to do nothing.  */
 	  if (allow_inverse_p)
 	    warning (0, "pointer to member cast via virtual base %qT",
@@ -5571,6 +5548,30 @@ get_delta_difference (tree from, tree to,
 		   BINFO_TYPE (virt_binfo));
 	}
     }
+  else if (same_type_ignoring_top_level_qualifiers_p (from, to))
+    /* Pointer to member of incomplete class is permitted*/;
+  else if (!allow_inverse_p)
+    {
+      error_not_base_type (from, to);
+      error ("   in pointer to member conversion");
+    }
+  else
+    {
+      binfo = lookup_base (from, to, c_cast_p ? ba_unique : ba_check, &kind);
+      if (binfo)
+	{
+	  if (kind != bk_via_virtual)
+	    result = size_diffop (size_zero_node, BINFO_OFFSET (binfo));
+	  else
+	    {
+	      /* This is a reinterpret cast, we choose to do nothing.  */
+	      tree virt_binfo = binfo_from_vbase (binfo);
+	  
+	      warning (0, "pointer to member cast via virtual base %qT",
+		       BINFO_TYPE (virt_binfo));
+	    }
+	}
+    }
 
   return fold_if_not_in_template (convert_to_integer (ptrdiff_type_node, 
 						      result));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c424bf5f0a1c..1a6bdc7ddf6a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2005-05-27  Nathan Sidwell  <nathan@codesourcery.com>
 
+	PR c++/21455
+	* g++.dg/inherit/ptrmem3.C: New.
+
 	PR c++/21681
 	* g++.dg/parse/template16.C: New.
 
diff --git a/gcc/testsuite/g++.dg/inherit/ptrmem3.C b/gcc/testsuite/g++.dg/inherit/ptrmem3.C
new file mode 100644
index 000000000000..0c06c65df204
--- /dev/null
+++ b/gcc/testsuite/g++.dg/inherit/ptrmem3.C
@@ -0,0 +1,17 @@
+// Copyright (C) 2005 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 27 May 2005 <nathan@codesourcery.com>
+
+// Origin:Andrew Pinski pinskia@gcc.gnu.org
+// PR 21455  bogus error with pointer to member of incomplete
+
+class XMLFile;
+
+typedef bool (XMLFile::*ParserFunctionPtr)();
+
+struct ParserElement
+{
+  ParserFunctionPtr getPreFunc() const { return preFunc; }
+  ParserFunctionPtr getPostFunc() const { return postFunc; }
+  ParserFunctionPtr preFunc;
+  ParserFunctionPtr postFunc;
+};