compiler built in is_scalar, use built-in is_scalar in libstdc++ std::is_scalar

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 9374327008b..f799ba2efd5 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3747,6 +3747,9 @@  diagnose_trait_expr (tree expr, tree args)
     case CPTK_IS_UNION:
       inform (loc, "  %qT is not a union", t1);
       break;
+    case CPTK_IS_SCALAR:
+      inform(loc, "  %qT is not a scalar type", t1);
+      break;
     case CPTK_IS_AGGREGATE:
       inform (loc, "  %qT is not an aggregate", t1);
       break;
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 823899a26c5..8dace289e88 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -82,6 +82,7 @@  DEFTRAIT_EXPR (IS_TRIVIALLY_ASSIGNABLE, "__is_trivially_assignable", 2)
 DEFTRAIT_EXPR (IS_TRIVIALLY_CONSTRUCTIBLE, "__is_trivially_constructible", -1)
 DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
 DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
+DEFTRAIT_EXPR (IS_SCALAR, "__is_scalar", 1)
 DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY, "__reference_constructs_from_temporary", 2)
 DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY, "__reference_converts_from_temporary", 2)
 
diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc
index bea52a608f1..a79359430a5 100644
--- a/gcc/cp/cxx-pretty-print.cc
+++ b/gcc/cp/cxx-pretty-print.cc
@@ -437,7 +437,8 @@  pp_cxx_userdef_literal (cxx_pretty_printer *pp, tree t)
      __is_polymorphic ( type-id )
      __is_std_layout ( type-id )
      __is_trivial ( type-id )
-     __is_union ( type-id )  */
+     __is_union ( type-id )
+     __is_scalar ( type-id )  */
 
 void
 cxx_pretty_printer::primary_expression (tree t)
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index b00a6cd5b8b..8465d4fbcdb 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -5577,6 +5577,7 @@  cp_parser_fold_expression (cp_parser *parser, tree expr1)
      __is_std_layout ( type-id )
      __is_trivial ( type-id )
      __is_union ( type-id )
+     __is_scalar ( type-id )
 
    Objective-C++ Extension:
 
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index db982d594e6..81b13d1ae5c 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12025,6 +12025,9 @@  trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_UNION:
       return type_code1 == UNION_TYPE;
 
+    case CPTK_IS_SCALAR:
+      return SCALAR_TYPE_P (type1);
+
     case CPTK_IS_ASSIGNABLE:
       return is_xible (MODIFY_EXPR, type1, type2);
 
@@ -12190,6 +12193,7 @@  finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_CLASS:
     case CPTK_IS_ENUM:
     case CPTK_IS_UNION:
+    case CPTK_IS_SCALAR:
     case CPTK_IS_SAME:
       break;
 
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index f343e153e56..4bf06a7a438 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -146,3 +146,7 @@ 
 #if !__has_builtin (__remove_cvref)
 # error "__has_builtin (__remove_cvref) failed"
 #endif
+#if !__has_builtin (__is_scalar)
+# error "__has_builtin (__is_scalar) failed"
+#endif
+
diff --git a/gcc/testsuite/g++.dg/ext/is_scalar.C b/gcc/testsuite/g++.dg/ext/is_scalar.C
new file mode 100644
index 00000000000..1d58f6ec475
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_scalar.C
@@ -0,0 +1,21 @@ 
+// { dg-do compile { target c++11 } }
+
+#define SA(X) static_assert((X),#X)
+
+struct S { int m; };
+
+enum class E {
+  e
+};
+
+int main() {
+  char* pNull= nullptr;
+
+  SA(__is_scalar(decltype(pNull)));
+  SA(__is_scalar(int));
+  SA(__is_scalar(double));
+  SA(__is_scalar(E));
+  SA(__is_scalar(char const *));
+  SA(!__is_scalar(struct S));
+  return 0;
+}
\ No newline at end of file
diff --git a/gcc/testsuite/g++.dg/tm/pr46567.C b/gcc/testsuite/g++.dg/tm/pr46567.C
index 6d791484448..760c7fd6cab 100644
--- a/gcc/testsuite/g++.dg/tm/pr46567.C
+++ b/gcc/testsuite/g++.dg/tm/pr46567.C
@@ -225,7 +225,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     : public __traitor<__is_void<_Tp>, __is_arithmetic<_Tp> >
     { };
   template<typename _Tp>
-    struct __is_scalar
+    struct __is_arith_or_ptr
     : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
     { };
   template<typename _Tp>
@@ -1325,7 +1325,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     }
   template<typename _ForwardIterator, typename _Tp>
     inline typename
-    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
+    __gnu_cxx::__enable_if<!__is_arith_or_ptr<_Tp>::__value, void>::__type
     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
        const _Tp& __value)
     {
@@ -1334,7 +1334,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     }
   template<typename _ForwardIterator, typename _Tp>
     inline typename
-    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
+    __gnu_cxx::__enable_if<__is_arith_or_ptr<_Tp>::__value, void>::__type
     __fill_a(_ForwardIterator __first, _ForwardIterator __last,
       const _Tp& __value)
     {
@@ -1362,7 +1362,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     }
   template<typename _OutputIterator, typename _Size, typename _Tp>
     inline typename
-    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
+    __gnu_cxx::__enable_if<!__is_arith_or_ptr<_Tp>::__value, _OutputIterator>::__type
     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
     {
       for (; __n > 0; --__n, ++__first)
@@ -1371,7 +1371,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     }
   template<typename _OutputIterator, typename _Size, typename _Tp>
     inline typename
-    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
+    __gnu_cxx::__enable_if<__is_arith_or_ptr<_Tp>::__value, _OutputIterator>::__type
     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)
     {
       const _Tp __tmp = __value;
diff --git a/gcc/testsuite/g++.dg/torture/pr57107.C b/gcc/testsuite/g++.dg/torture/pr57107.C
index 4dbd32bd298..42ec0c8d350 100644
--- a/gcc/testsuite/g++.dg/torture/pr57107.C
+++ b/gcc/testsuite/g++.dg/torture/pr57107.C
@@ -27,7 +27,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     };
     template<typename _Tp>     struct __is_arithmetic     : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >     {
     };
-    template<typename _Tp>     struct __is_scalar     : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >     {
+    template<typename _Tp>     struct __is_arith_or_ptr     : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >     {
     };
 }
 namespace __gnu_cxx __attribute__ ((__visibility__ ("default"))) {
@@ -54,7 +54,7 @@  namespace std __attribute__ ((__visibility__ ("default"))) {
     };
     template<typename _Iterator>     inline typename _Niter_base<_Iterator>::iterator_type     __niter_base(_Iterator __it)     {
     }
-    template<typename _OutputIterator, typename _Size, typename _Tp>     inline typename     __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)     {
+    template<typename _OutputIterator, typename _Size, typename _Tp>     inline typename     __gnu_cxx::__enable_if<!__is_arith_or_ptr<_Tp>::__value, _OutputIterator>::__type     __fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value)     {
 	for (__decltype(__n + 0) __niter = __n;
 	     __niter > 0;
 	     --__niter, ++__first)  *__first = __value;
diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
index 4312f32a4e0..54a157ff960 100644
--- a/libstdc++-v3/include/bits/cpp_type_traits.h
+++ b/libstdc++-v3/include/bits/cpp_type_traits.h
@@ -385,11 +385,11 @@  __INT_N(__GLIBCXX_TYPE_INT_N_3)
     : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
     { };
 
-  //
-  // A scalar type is an arithmetic type or a pointer type
-  // 
+//  //
+//  // A scalar type is an arithmetic type or a pointer type
+//  //
   template<typename _Tp>
-    struct __is_scalar
+    struct __is_arith_or_ptr
     : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
     { };
 
diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h
index 4a6f8195d98..3922386f834 100644
--- a/libstdc++-v3/include/bits/stl_algobase.h
+++ b/libstdc++-v3/include/bits/stl_algobase.h
@@ -911,7 +911,7 @@  _GLIBCXX_END_NAMESPACE_CONTAINER
   template<typename _ForwardIterator, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline typename
-    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
+    __gnu_cxx::__enable_if<!__is_arith_or_ptr<_Tp>::__value, void>::__type
     __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
 	      const _Tp& __value)
     {
@@ -922,7 +922,7 @@  _GLIBCXX_END_NAMESPACE_CONTAINER
   template<typename _ForwardIterator, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline typename
-    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
+    __gnu_cxx::__enable_if<__is_arith_or_ptr<_Tp>::__value, void>::__type
     __fill_a1(_ForwardIterator __first, _ForwardIterator __last,
 	      const _Tp& __value)
     {
@@ -1060,7 +1060,7 @@  _GLIBCXX_END_NAMESPACE_CONTAINER
   template<typename _OutputIterator, typename _Size, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline typename
-    __gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
+    __gnu_cxx::__enable_if<!__is_arith_or_ptr<_Tp>::__value, _OutputIterator>::__type
     __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
     {
       for (; __n > 0; --__n, (void) ++__first)
@@ -1071,7 +1071,7 @@  _GLIBCXX_END_NAMESPACE_CONTAINER
   template<typename _OutputIterator, typename _Size, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline typename
-    __gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
+        __gnu_cxx::__enable_if<__is_arith_or_ptr<_Tp>::__value, _OutputIterator>::__type
     __fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
     {
       const _Tp __tmp = __value;
diff --git a/libstdc++-v3/include/bits/valarray_array.h b/libstdc++-v3/include/bits/valarray_array.h
index 222fd5fd900..af259383648 100644
--- a/libstdc++-v3/include/bits/valarray_array.h
+++ b/libstdc++-v3/include/bits/valarray_array.h
@@ -90,7 +90,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline void
     __valarray_default_construct(_Tp* __b, _Tp* __e)
     {
-      _Array_default_ctor<_Tp, __is_scalar<_Tp>::__value>::_S_do_it(__b, __e);
+      _Array_default_ctor<_Tp, __is_arith_or_ptr<_Tp>::__value>::_S_do_it(__b, __e);
     }
 
   // Turn a raw-memory into an array of _Tp filled with __t
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 2bd607a8b8f..2dfc79cbe01 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -678,11 +678,18 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_member_pointer;
 
   /// is_scalar
+#if __has_builtin(__is_scalar)
+  template<typename _Tp>
+  struct is_scalar
+      : public __bool_constant<__is_scalar(_Tp)>
+  { };
+#else
   template<typename _Tp>
     struct is_scalar
     : public __or_<is_arithmetic<_Tp>, is_enum<_Tp>, is_pointer<_Tp>,
                    is_member_pointer<_Tp>, is_null_pointer<_Tp>>::type
     { };
+#endif
 
   /// is_compound
   template<typename _Tp>