re PR ipa/68148 (Devirtualization only applies to last of multiple successive calls)

	PR ipa/68148
	* ipa-icf.c (sem_function::merge): Virtual functions may become
	reachable even if they address is not taken and there are no
	idrect calls.
	* g++.dg/ipa/devirt-49.C: New testcase.

From-SVN: r232410

gcc/ChangeLog

 2016-01-15  Jan Hubicka  <hubicka@ucw.cz>
 
+	PR ipa/68148
+	* ipa-icf.c (sem_function::merge): Virtual functions may become
+	reachable even if they address is not taken and there are no
+	idrect calls.
+
+2016-01-15  Jan Hubicka  <hubicka@ucw.cz>
+
 	* lto-streamer-out.c (subtract_estimated_size): New function.
 	(get_symbol_initial_value): Use it.
 

gcc/ipa-icf.c

@@ -1305,6 +1305,7 @@ sem_function::merge (sem_item *alias_item)
 
       /* If all callers was redirected, do not produce wrapper.  */
       if (alias->can_remove_if_no_direct_calls_p ()
+	  && !DECL_VIRTUAL_P (alias->decl)
 	  && !alias->has_aliases_p ())
 	{
 	  create_wrapper = false;

gcc/testsuite/ChangeLog

+2016-01-15  Jan Hubicka <hubicka@ucw.cz>
+
+	PR ipa/68148
+	* g++.dg/ipa/devirt-49.C: New testcase.
+
 2016-01-15  Christian Bruel  <christian.bruel@st.com>
 
 	PR target/65837

gcc/testsuite/g++.dg/ipa/devirt-49.C

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-ipa-devirt"  } */
+struct Interface {
+  virtual ~Interface() {}
+  virtual void virtualFunc() = 0;
+  virtual void virtualFunc2() = 0;
+};
+
+struct Concrete : Interface {
+  int counter_;
+  Concrete() : counter_(0) {}
+  void virtualFunc() { counter_++; }
+  void virtualFunc2() { counter_++; }
+};
+
+void test(Interface &c) {
+  c.virtualFunc();
+  c.virtualFunc2();
+}
+/* { dg-final { scan-ipa-dump "2 speculatively devirtualized" "devirt"  } } */