re PR c++/87506 (ICE with inherited constexpr constructor with const argument)

	PR c++/87506
	* constexpr.c (adjust_temp_type): Handle EMPTY_CLASS_EXPR.

	* g++.dg/cpp0x/constexpr-87506.C: New test.

From-SVN: r266877

gcc/cp/ChangeLog

+2018-12-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/87506
+	* constexpr.c (adjust_temp_type): Handle EMPTY_CLASS_EXPR.
+
 2018-12-06  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* class.c (check_bitfield_decl): In error message about non-integral
@@ -6,7 +11,7 @@
 	friends; when calling build_decl for a FIELD_DECL possibly pass the
 	declarator->id_loc.
 
-2018-12-06  Alexandre Oliva <aoliva@redhat.com>
+2018-12-06  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR c++/86747
 	* pt.c (tsubst_friend_class): Enter tsubsted class context.

gcc/cp/constexpr.c

@@ -1281,6 +1281,8 @@ adjust_temp_type (tree type, tree temp)
   /* Avoid wrapping an aggregate value in a NOP_EXPR.  */
   if (TREE_CODE (temp) == CONSTRUCTOR)
     return build_constructor (type, CONSTRUCTOR_ELTS (temp));
+  if (TREE_CODE (temp) == EMPTY_CLASS_EXPR)
+    return build0 (EMPTY_CLASS_EXPR, type);
   gcc_assert (scalarish_type_p (type));
   return cp_fold_convert (type, temp);
 }

gcc/testsuite/ChangeLog

+2018-12-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/87506
+	* g++.dg/cpp0x/constexpr-87506.C: New test.
+
 2018-12-06  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* g++.dg/parse/bitfield7.C: New.
@@ -5,7 +10,7 @@
 	* g++.dg/parse/bitfield1.C: Likewise.
 	* g++.dg/parse/bitfield2.C: Likewise.
 
-2018-12-06  Alexandre Oliva <aoliva@redhat.com>
+2018-12-06  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR c++/86747
 	* g++.dg/pr86747.C: New.

gcc/testsuite/g++.dg/cpp0x/constexpr-87506.C

+// PR c++/87506
+// { dg-do compile { target c++11 } }
+
+struct A {};
+struct B { constexpr B (const A) {} };
+struct C : B { using B::B; };
+
+void
+foo ()
+{
+  C c (A{});
+}