Fix lto/PR60854

[Jan Hubicka]

Hi,
the testcase shows problem where cpp implicit alias is always inline and
symtab_remove_unreachable_nodes removes the body of aliased function before
inlininghappens.  The real problem is that cgraph_state is set too early
and not as the comment says after inlinig, but for release branch I think
it is easier to sovle the problem by simply making the alias target
reachable by hand.

Bootstrapped/regtested x86_64-linux, comitted to trunk. Let me know
when it is OK for release brach.

Honza

Index: ChangeLog
===================================================================
--- ChangeLog   (revision 209458)
+++ ChangeLog   (working copy)
@@ -1,3 +1,9 @@
+2014-04-16  Jan Hubicka  <hubi...@ucw.cz>
+
+       PR ipa/60854
+       * ipa.c (symtab_remove_unreachable_nodes): Mark targets of
+       external aliases alive, too.
+
 2014-04-16  Andrew  Pinski  <apin...@cavium.com>
 
        * config/host-linux.c (TRY_EMPTY_VM_SPACE): Change aarch64 ilp32
Index: testsuite/ChangeLog
===================================================================
--- testsuite/ChangeLog (revision 209450)
+++ testsuite/ChangeLog (working copy)
@@ -1,3 +1,8 @@
+2014-04-16  Jan Hubicka  <hubi...@ucw.cz>
+
+       PR ipa/60854
+       * g++.dg/torture/pr60854.C: New testcase.
+
 2014-04-16  Catherine Moore  <c...@codesourcery.com>
 
        * gcc.target/mips/umips-store16-2.c: New test.
Index: ipa.c
===================================================================
--- ipa.c       (revision 209450)
+++ ipa.c       (working copy)
@@ -415,7 +415,18 @@ symtab_remove_unreachable_nodes (bool be
                          || !DECL_EXTERNAL (e->callee->decl)
                          || e->callee->alias
                          || before_inlining_p))
-                   pointer_set_insert (reachable, e->callee);
+                   {
+                     /* Be sure that we will not optimize out alias target
+                        body.  */
+                     if (DECL_EXTERNAL (e->callee->decl)
+                         && e->callee->alias
+                         && before_inlining_p)
+                       {
+                         pointer_set_insert (reachable,
+                                             cgraph_function_node (e->callee));
+                       }
+                     pointer_set_insert (reachable, e->callee);
+                   }
                  enqueue_node (e->callee, &first, reachable);
                }
 
Index: testsuite/g++.dg/torture/pr60854.C
===================================================================
--- testsuite/g++.dg/torture/pr60854.C  (revision 0)
+++ testsuite/g++.dg/torture/pr60854.C  (revision 0)
@@ -0,0 +1,13 @@
+template <typename T>
+class MyClass
+{
+public:
+  __attribute__ ((__always_inline__)) inline MyClass () { ; }
+};
+
+extern template class MyClass<double>;
+
+void Func()
+{
+  MyClass<double> x;
+}