Fix wrong assumption in contains_type_p (PR ipa/71207).

2017-01-17  Martin Liska  <mliska@suse.cz>

	PR ipa/71207
	* g++.dg/ipa/pr71207.C: New test.
2017-01-17  Martin Liska  <mliska@suse.cz>

	PR ipa/71207
	* ipa-polymorphic-call.c (contains_type_p): Fix wrong
	assumption and add comment.

From-SVN: r244530

gcc/ChangeLog

+2017-01-17  Martin Liska  <mliska@suse.cz>
+
+	PR ipa/71207
+	* ipa-polymorphic-call.c (contains_type_p): Fix wrong
+	assumption and add comment.
+
 2017-01-17  Nathan Sidwell  <nathan@acm.org>
 
 	* ipa-visibility.c (localize_node): New function, broken out of ...

gcc/ipa-polymorphic-call.c

@@ -463,12 +463,12 @@ contains_type_p (tree outer_type, HOST_WIDE_INT offset,
   /* Check that type is within range.  */
   if (offset < 0)
     return false;
-  if (TYPE_SIZE (outer_type) && TYPE_SIZE (otr_type)
-      && TREE_CODE (TYPE_SIZE (outer_type)) == INTEGER_CST
-      && TREE_CODE (TYPE_SIZE (otr_type)) == INTEGER_CST
-      && wi::ltu_p (wi::to_offset (TYPE_SIZE (outer_type)),
-		    (wi::to_offset (TYPE_SIZE (otr_type)) + offset)))
-    return false;
+
+  /* PR ipa/71207
+     As OUTER_TYPE can be a type which has a diamond virtual inheritance,
+     it's not necessary that INNER_TYPE will fit within OUTER_TYPE with
+     a given offset.  It can happen that INNER_TYPE also contains a base object,
+     however it would point to the same instance in the OUTER_TYPE.  */
 
   context.offset = offset;
   context.outer_type = TYPE_MAIN_VARIANT (outer_type);

gcc/testsuite/ChangeLog

+2017-01-17  Martin Liska  <mliska@suse.cz>
+
+	PR ipa/71207
+	* g++.dg/ipa/pr71207.C: New test.
+
 2017-01-17  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR middle-end/77445

gcc/testsuite/g++.dg/ipa/pr71207.C

+/* PR ipa/71207 */
+/* { dg-do run } */
+
+class Class1
+{
+public:
+  Class1() {};
+  virtual ~Class1() {};
+
+protected:
+  unsigned Field1;
+};
+
+class Class2 : public virtual Class1
+{
+};
+
+class Class3 : public virtual Class1
+{
+public:
+  virtual void Method1() = 0;
+
+  void Method2()
+  {
+    Method1();
+  }
+};
+
+class Class4 : public Class2, public virtual Class3
+{
+public:
+  Class4() {};
+  virtual void Method1() {};
+};
+
+int main()
+{
+  Class4 var1;
+  var1.Method2();
+
+  return 0;
+}