C++0x constexpr PATCH #4: is_literal_type

commit bc25eceef8f718c792a25efbb8b6d1ecd6f7f131
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Oct 26 14:49:50 2010 -0400

    gcc/c-family/
    	* c-common.c (c_common_reswords): Add __is_literal_type.
    	* c-common.h (enum rid): Add RID_IS_LITERAL_TYPE.
    gcc/cp/
    	* cp-tree.h (cp_trait_kind): Add CPTK_IS_LITERAL_TYPE.
    	* cxx-pretty-print.c (pp_cxx_trait_expression): Handle it.
    	* semantics.c (trait_expr_value, finish_trait_expr): Likewise.
    	* parser.c (cp_parser_primary_expression): Handle RID_IS_LITERAL_TYPE.
    	(cp_parser_trait_expr): Likewise.
    libstdc++-v3/
    	* include/std/type_traits (is_literal_type): New.

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 98568e8..3cdc663 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -439,6 +439,7 @@  const struct c_common_resword c_common_reswords[] =
   { "__is_standard_layout", RID_IS_STD_LAYOUT, D_CXXONLY },
   { "__is_trivial",     RID_IS_TRIVIAL, D_CXXONLY },
   { "__is_union",	RID_IS_UNION,	D_CXXONLY },
+  { "__is_literal_type", RID_IS_LITERAL_TYPE, D_CXXONLY },
   { "__imag",		RID_IMAGPART,	0 },
   { "__imag__",		RID_IMAGPART,	0 },
   { "__inline",		RID_INLINE,	0 },
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index aa877d4..f2c6958 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -140,7 +140,7 @@  enum rid
   RID_IS_EMPTY,                RID_IS_ENUM,
   RID_IS_POD,                  RID_IS_POLYMORPHIC,
   RID_IS_STD_LAYOUT,           RID_IS_TRIVIAL,
-  RID_IS_UNION,
+  RID_IS_UNION,                RID_IS_LITERAL_TYPE,
 
   /* C++0x */
   RID_CONSTEXPR, RID_DECLTYPE, RID_NOEXCEPT, RID_NULLPTR, RID_STATIC_ASSERT,
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 1cd776a..7595b6f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -567,6 +567,7 @@  typedef enum cp_trait_kind
   CPTK_IS_POLYMORPHIC,
   CPTK_IS_STD_LAYOUT,
   CPTK_IS_TRIVIAL,
+  CPTK_IS_LITERAL_TYPE,
   CPTK_IS_UNION
 } cp_trait_kind;
 
diff --git a/gcc/cp/cxx-pretty-print.c b/gcc/cp/cxx-pretty-print.c
index bbef227..09fcc49 100644
--- a/gcc/cp/cxx-pretty-print.c
+++ b/gcc/cp/cxx-pretty-print.c
@@ -2369,6 +2369,9 @@  pp_cxx_trait_expression (cxx_pretty_printer *pp, tree t)
     case CPTK_IS_UNION:
       pp_cxx_ws_string (pp, "__is_union");
       break;
+    case CPTK_IS_LITERAL_TYPE:
+      pp_cxx_ws_string (pp, "__is_literal_type");
+      break;
 
     default:
       gcc_unreachable ();
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0d28345..360e197 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -3814,6 +3814,7 @@  cp_parser_primary_expression (cp_parser *parser,
 	case RID_IS_STD_LAYOUT:
 	case RID_IS_TRIVIAL:
 	case RID_IS_UNION:
+	case RID_IS_LITERAL_TYPE:
 	  return cp_parser_trait_expr (parser, token->keyword);
 
 	/* Objective-C++ expressions.  */
@@ -7365,6 +7366,9 @@  cp_parser_trait_expr (cp_parser* parser, enum rid keyword)
     case RID_IS_UNION:
       kind = CPTK_IS_UNION;
       break;
+    case RID_IS_LITERAL_TYPE:
+      kind = CPTK_IS_LITERAL_TYPE;
+      break;
     default:
       gcc_unreachable ();
     }
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 0ca8c33..5926963 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -5104,6 +5104,9 @@  trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_UNION:
       return (type_code1 == UNION_TYPE);
 
+    case CPTK_IS_LITERAL_TYPE:
+      return (literal_type_p (type1));
+
     default:
       gcc_unreachable ();
       return false;
@@ -5152,6 +5155,7 @@  finish_trait_expr (cp_trait_kind kind, tree type1, tree type2)
 	      || kind == CPTK_IS_POLYMORPHIC
 	      || kind == CPTK_IS_STD_LAYOUT
 	      || kind == CPTK_IS_TRIVIAL
+	      || kind == CPTK_IS_LITERAL_TYPE
 	      || kind == CPTK_IS_UNION);
 
   if (kind == CPTK_IS_CONVERTIBLE_TO)
@@ -5195,6 +5199,7 @@  finish_trait_expr (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_POLYMORPHIC:
     case CPTK_IS_STD_LAYOUT:
     case CPTK_IS_TRIVIAL:
+    case CPTK_IS_LITERAL_TYPE:
       if (!check_trait_type (type1))
 	{
 	  error ("incomplete type %qT not allowed", type1);
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-is_literal.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-is_literal.C
new file mode 100644
index 0000000..d1b9543
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-is_literal.C
@@ -0,0 +1,38 @@ 
+// { dg-options -std=c++0x }
+
+#include <type_traits>
+
+#define IS_LIT(T) (std::is_literal_type<T>::value)
+#define SA(X) static_assert (X, #X)
+#define YES(T) SA(IS_LIT(T))
+#define NO(T) SA(!IS_LIT(T))
+
+enum E1 { };
+enum class E2 { };
+struct Literal {};
+
+struct NotLiteral {
+  ~NotLiteral();
+};
+
+YES(int);
+YES(int[]);
+YES(int[3]);
+YES(double);
+YES(void *);
+YES(decltype (nullptr));
+YES(int Literal::*);
+YES(void (Literal::*)());
+YES(E1);
+YES(E2);
+YES(Literal);
+NO (NotLiteral);
+YES(NotLiteral *);
+YES(NotLiteral NotLiteral::*);
+YES(NotLiteral (NotLiteral::*)(NotLiteral));
+
+struct A {
+  A(const A&) = default;
+};
+
+NO(A);				// no constexpr ctor other than copy
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index cde741e..a5a62d6 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -192,6 +192,12 @@  namespace std
     : public integral_constant<bool, __is_pod(_Tp)>
     { };
 
+  /// is_literal_type
+  template<typename _Tp>
+    struct is_literal_type
+    : public integral_constant<bool, __is_literal_type(_Tp)>
+    { };
+
   template<typename _Tp>
     typename add_rvalue_reference<_Tp>::type declval() noexcept;
 
diff --git a/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc b/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
index f0c6546..b18ff2f 100644
--- a/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
@@ -19,7 +19,7 @@ 
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
-// { dg-error "static assertion failed" "" { target *-*-* } 682 }
+// { dg-error "static assertion failed" "" { target *-*-* } 688 }
 
 #include <utility>
 
diff --git a/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc b/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
index 8a09c65..d74f4e63 100644
--- a/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
@@ -48,5 +48,5 @@  void test01()
 // { dg-error "instantiated from here" "" { target *-*-* } 40 }
 // { dg-error "instantiated from here" "" { target *-*-* } 42 }
 
-// { dg-error "invalid use of incomplete type" "" { target *-*-* } 645 }
-// { dg-error "declaration of" "" { target *-*-* } 609 }
+// { dg-error "invalid use of incomplete type" "" { target *-*-* } 651 }
+// { dg-error "declaration of" "" { target *-*-* } 615 }
diff --git a/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc b/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
index ba68414..18fd4fb 100644
--- a/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
@@ -48,5 +48,5 @@  void test01()
 // { dg-error "instantiated from here" "" { target *-*-* } 40 }
 // { dg-error "instantiated from here" "" { target *-*-* } 42 }
 
-// { dg-error "invalid use of incomplete type" "" { target *-*-* } 568 }
-// { dg-error "declaration of" "" { target *-*-* } 532 }
+// { dg-error "invalid use of incomplete type" "" { target *-*-* } 574 }
+// { dg-error "declaration of" "" { target *-*-* } 538 }