re PR c++/85553 (cannot list-initialize a variable of type std::nullptr_t)

	PR c++/85553
	* init.c (build_zero_init_1): For zero initialization of
	NULLPTR_TYPE_P type use build_int_cst directly.

	* g++.dg/cpp0x/Wzero-as-null-pointer-constant-3.C: Add dg-bogus
	directive.
	* g++.dg/cpp0x/constexpr-85553.C: New test.

From-SVN: r259728

gcc/cp/ChangeLog

+2018-04-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85553
+	* init.c (build_zero_init_1): For zero initialization of
+	NULLPTR_TYPE_P type use build_int_cst directly.
+
 2018-04-27  David Malcolm  <dmalcolm@redhat.com>
 
 	PR c++/85515

gcc/cp/init.c

@@ -180,8 +180,10 @@ build_zero_init_1 (tree type, tree nelts, bool static_storage_p,
        items with static storage duration that are not otherwise
        initialized are initialized to zero.  */
     ;
-  else if (TYPE_PTR_OR_PTRMEM_P (type) || NULLPTR_TYPE_P (type))
+  else if (TYPE_PTR_OR_PTRMEM_P (type))
     init = fold (convert (type, nullptr_node));
+  else if (NULLPTR_TYPE_P (type))
+    init = build_int_cst (type, 0);
   else if (SCALAR_TYPE_P (type))
     init = fold (convert (type, integer_zero_node));
   else if (RECORD_OR_UNION_CODE_P (TREE_CODE (type)))

gcc/testsuite/ChangeLog

+2018-04-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85553
+	* g++.dg/cpp0x/Wzero-as-null-pointer-constant-3.C: Add dg-bogus
+	directive.
+	* g++.dg/cpp0x/constexpr-85553.C: New test.
+
 2018-04-27  David Malcolm  <dmalcolm@redhat.com>
 
 	PR c++/85515

gcc/testsuite/g++.dg/cpp0x/Wzero-as-null-pointer-constant-3.C

@@ -3,4 +3,4 @@
 // { dg-options "-Wzero-as-null-pointer-constant" }
 
 int* no_warn = {};
-decltype( nullptr ) warn = {};
+decltype( nullptr ) warn = {};	// { dg-bogus "zero as null pointer constant" }

gcc/testsuite/g++.dg/cpp0x/constexpr-85553.C

+// PR c++/85553
+// { dg-do compile { target c++11 } }
+using T = decltype(nullptr);
+const constexpr T foo{};