Backport the fix for PR47714 to the 4.5 branch

[Duncan Sands]

The following patch backports the one-line fix for PR47714 from the 4.6 branch
to the 4.5 branch.  I hit this while working on the dragonegg plugin.  OK to
apply?

Ciao, Duncan.

Index: gcc/cp/method.c
===================================================================
--- gcc/cp/method.c     (revision 173485)
+++ gcc/cp/method.c     (working copy)
@@ -374,6 +374,7 @@
       DECL_CONTEXT (x) = thunk_fndecl;
       SET_DECL_RTL (x, NULL_RTX);
       DECL_HAS_VALUE_EXPR_P (x) = 0;
+      TREE_ADDRESSABLE (x) = 0;
       t = x;
     }
   a = nreverse (t);
Index: gcc/cp/ChangeLog
===================================================================
--- gcc/cp/ChangeLog    (revision 173485)
+++ gcc/cp/ChangeLog    (working copy)
@@ -1,3 +1,11 @@
+2011-05-31  Duncan Sands  <baldr...@free.fr>
+
+       Backported from 4.6 branch
+       2011-03-09  Martin Jambor  <mjam...@suse.cz>
+
+       PR tree-optimization/47714
+       * method.c (use_thunk): Clear addressable flag of thunk arguments.
+
 2011-04-27  Jason Merrill  <ja...@redhat.com>

        PR c++/48046
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog     (revision 173485)
+++ gcc/testsuite/ChangeLog     (working copy)
@@ -1,3 +1,11 @@
+2011-05-31  Duncan Sands  <baldr...@free.fr>
+
+       Backported from 4.6 branch
+       2011-03-09  Martin Jambor  <mjam...@suse.cz>
+
+       PR tree-optimization/47714
+       * g++.dg/torture/pr47714.C: New test.
+
 2011-05-05  Jason Merrill  <ja...@redhat.com>

        * g++.dg/init/new30.C: New.
Index: gcc/testsuite/g++.dg/torture/pr47714.C
===================================================================
--- gcc/testsuite/g++.dg/torture/pr47714.C      (revision 0)
+++ gcc/testsuite/g++.dg/torture/pr47714.C      (revision 0)
@@ -0,0 +1,16 @@
+struct A { virtual ~A () {} };
+struct B { virtual ~B () {} };
+struct C { virtual const A *foo (int) const = 0; };
+struct E : public B, public A { };
+struct F : public C
+{
+  virtual const E *foo (int) const;
+};
+void bar (int &);
+
+const E *
+F::foo (int x) const
+{
+  bar (x);
+  return __null;
+}