re PR c++/52706 ([C++11] Demangling of templates with std::nullptr_t as non-type parameter)

	PR c++/52706
	* mangle.c (write_type): nullptr_t is a builtin type.

From-SVN: r186469

gcc/common.opt

@@ -788,6 +788,8 @@ Driver Undocumented
 ;    argument.
 ;    First selectable in G++ 4.7.
 ;
+; 7: The version of the ABI that treats nullptr_t as a builtin type.
+;    First selectable in G++ 4.8.
 ; Additional positive integers will be assigned as new versions of
 ; the ABI become the default version of the ABI.
 fabi-version=

gcc/cp/ChangeLog

+2012-04-15  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52706
+	* mangle.c (write_type): nullptr_t is a builtin type.
+
 2012-04-14  Jan Hubicka  <jh@suse.cz>
 
 	* tree.c: Update field referenced for new cgraph/varpool layout.

gcc/cp/mangle.c

@@ -2023,6 +2023,8 @@ write_type (tree type)
 
 	    case NULLPTR_TYPE:
 	      write_string ("Dn");
+	      if (abi_version_at_least (7))
+		++is_builtin_type;
 	      break;
 
 	    case TYPEOF_TYPE:

gcc/testsuite/ChangeLog

 2012-04-15  Jason Merrill  <jason@redhat.com>
 
+	PR c++/52706
+	* g++.dg/cpp0x/nullptr27.C: New.
+
 	PR c++/52818
 	* g++.dg/warn/format8.C: New.
 

gcc/testsuite/g++.dg/cpp0x/nullptr27.C

+// PR c++/52706
+// { dg-options "-std=c++11 -fabi-version=0" }
+// { dg-final { scan-assembler "_Z1fIDnLDn0EEiT_" } }
+
+template<class T, decltype(nullptr) = nullptr>
+int f(T);
+
+int i2 = f(nullptr); // 17