1 files changed, 52 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/abi/covariant5.C b/gcc/testsuite/g++.dg/abi/covariant5.C
new file mode 100644
index 000000000..03e55583d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/covariant5.C
@@ -0,0 +1,52 @@
+// Copyright (C) 2005 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 4 Apr 2005 <nathan@codesourcery.com>
+
+// { dg-do run }
+
+// PR 20746: Covariant return pointer could be null.
+
+// Origin: yanliu@ca.ibm.com
+//         nathan@codesourcery.com
+
+struct A {
+  virtual void One ();
+};
+struct B  { 
+  virtual B *Two ();
+  virtual B &Three ();
+};
+
+struct C : A, B
+{
+  virtual C *Two (); 
+  virtual C &Three (); 
+};
+void A::One () {}
+B *B::Two()    {return this;}
+B &B::Three()    {return *this;}
+C *C::Two ()   {return 0;}
+C &C::Three ()   {return *(C *)0;}
+
+B *Foo (B *b)
+{
+  return b->Two ();
+}
+
+B &Bar (B *b)
+{
+  return b->Three ();
+}
+
+int main ()
+{
+  C c;
+
+  /* We should not adjust a null pointer.  */
+  if (Foo (&c))
+    return 1;
+  /* But we should adjust a (bogus) null reference.  */
+  if (!&Bar (&c))
+    return 2;
+
+  return 0;
+}