re PR c++/77375 (constant object with mutable subobject allocated in read-only memory)

	PR c++/77375
	* class.c (check_bases): Set CLASSTYPE_HAS_MUTABLE if any TYPE_HAS_MUTABLE_P
	for any bases.

	* g++.dg/cpp0x/mutable1.C: New test.

From-SVN: r240195

gcc/cp/ChangeLog

+2016-09-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/77375
+	* class.c (check_bases): Set CLASSTYPE_HAS_MUTABLE if any
+	TYPE_HAS_MUTABLE_P for any bases.
+
 2016-09-16  Jason Merrill  <jason@redhat.com>
 
 	* class.c (check_bases, set_one_vmethod_tm_attributes): Use

gcc/cp/class.c

@@ -1796,6 +1796,8 @@ check_bases (tree t,
       SET_CLASSTYPE_REF_FIELDS_NEED_INIT
 	(t, CLASSTYPE_REF_FIELDS_NEED_INIT (t)
 	 | CLASSTYPE_REF_FIELDS_NEED_INIT (basetype));
+      if (TYPE_HAS_MUTABLE_P (basetype))
+	CLASSTYPE_HAS_MUTABLE (t) = 1;
 
       /*  A standard-layout class is a class that:
 	  ...

gcc/testsuite/ChangeLog

+2016-09-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/77375
+	* g++.dg/cpp0x/mutable1.C: New test.
+
 2016-09-16  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/77612

gcc/testsuite/g++.dg/cpp0x/mutable1.C

+// PR c++/77375
+// { dg-do run { target c++11 } }
+
+struct Base { mutable int i; };
+struct Derived : Base {};
+const Derived foo{};
+
+int
+main ()
+{
+  foo.i = 42;
+}