PR libstdc++/82644 define TR1 hypergeometric functions in strict modes

diff --git a/libstdc++-v3/include/tr1/cmath b/libstdc++-v3/include/tr1/cmath
index d1df3804120..c07dd5c73a5 100644
--- a/libstdc++-v3/include/tr1/cmath
+++ b/libstdc++-v3/include/tr1/cmath
@@ -1160,10 +1160,6 @@  namespace tr1
   using std::comp_ellint_3l;
   using std::comp_ellint_3;
 
-  using __gnu_cxx::conf_hypergf;
-  using __gnu_cxx::conf_hypergl;
-  using __gnu_cxx::conf_hyperg;
-
   using std::cyl_bessel_if;
   using std::cyl_bessel_il;
   using std::cyl_bessel_i;
@@ -1200,10 +1196,6 @@  namespace tr1
   using std::hermitel;
   using std::hermite;
 
-  using __gnu_cxx::hypergf;
-  using __gnu_cxx::hypergl;
-  using __gnu_cxx::hyperg;
-
   using std::laguerref;
   using std::laguerrel;
   using std::laguerre;
@@ -1246,7 +1238,6 @@  _GLIBCXX_END_NAMESPACE_VERSION
 #include <tr1/beta_function.tcc>
 #include <tr1/ell_integral.tcc>
 #include <tr1/exp_integral.tcc>
-#include <tr1/hypergeometric.tcc>
 #include <tr1/legendre_function.tcc>
 #include <tr1/modified_bessel_func.tcc>
 #include <tr1/poly_hermite.tcc>
@@ -1372,23 +1363,6 @@  namespace tr1
     }
 
   inline float
-  conf_hypergf(float __a, float __c, float __x)
-  { return __detail::__conf_hyperg<float>(__a, __c, __x); }
-
-  inline long double
-  conf_hypergl(long double __a, long double __c, long double __x)
-  { return __detail::__conf_hyperg<long double>(__a, __c, __x); }
-
-  ///  5.2.1.7  Confluent hypergeometric functions.
-  template<typename _Tpa, typename _Tpc, typename _Tp>
-    inline typename __gnu_cxx::__promote_3<_Tpa, _Tpc, _Tp>::__type
-    conf_hyperg(_Tpa __a, _Tpc __c, _Tp __x)
-    {
-      typedef typename __gnu_cxx::__promote_3<_Tpa, _Tpc, _Tp>::__type __type;
-      return __detail::__conf_hyperg<__type>(__a, __c, __x);
-    }
-
-  inline float
   cyl_bessel_if(float __nu, float __x)
   { return __detail::__cyl_bessel_i<float>(__nu, __x); }
 
@@ -1542,23 +1516,6 @@  namespace tr1
     }
 
   inline float
-  hypergf(float __a, float __b, float __c, float __x)
-  { return __detail::__hyperg<float>(__a, __b, __c, __x); }
-
-  inline long double
-  hypergl(long double __a, long double __b, long double __c, long double __x)
-  { return __detail::__hyperg<long double>(__a, __b, __c, __x); }
-
-  ///  5.2.1.17  Hypergeometric functions.
-  template<typename _Tpa, typename _Tpb, typename _Tpc, typename _Tp>
-    inline typename __gnu_cxx::__promote_4<_Tpa, _Tpb, _Tpc, _Tp>::__type
-    hyperg(_Tpa __a, _Tpb __b, _Tpc __c, _Tp __x)
-    {
-      typedef typename __gnu_cxx::__promote_4<_Tpa, _Tpb, _Tpc, _Tp>::__type __type;
-      return __detail::__hyperg<__type>(__a, __b, __c, __x);
-    }
-
-  inline float
   laguerref(unsigned int __n, float __x)
   { return __detail::__laguerre<float>(__n, __x); }
 
@@ -1668,4 +1625,77 @@  namespace tr1
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
+#if _GLIBCXX_USE_STD_SPEC_FUNCS && !defined(__STRICT_ANSI__)
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace tr1
+{
+  using __gnu_cxx::conf_hypergf;
+  using __gnu_cxx::conf_hypergl;
+  using __gnu_cxx::conf_hyperg;
+
+  using __gnu_cxx::hypergf;
+  using __gnu_cxx::hypergl;
+  using __gnu_cxx::hyperg;
+} // namespace tr1
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#else // ! (_GLIBCXX_USE_STD_SPEC_FUNCS && !defined(__STRICT_ANSI__))
+
+#include <bits/stl_algobase.h>
+#include <limits>
+#include <tr1/type_traits>
+
+#include <tr1/hypergeometric.tcc>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+namespace tr1
+{
+  inline float
+  conf_hypergf(float __a, float __c, float __x)
+  { return __detail::__conf_hyperg<float>(__a, __c, __x); }
+
+  inline long double
+  conf_hypergl(long double __a, long double __c, long double __x)
+  { return __detail::__conf_hyperg<long double>(__a, __c, __x); }
+
+  ///  5.2.1.7  Confluent hypergeometric functions.
+  template<typename _Tpa, typename _Tpc, typename _Tp>
+    inline typename __gnu_cxx::__promote_3<_Tpa, _Tpc, _Tp>::__type
+    conf_hyperg(_Tpa __a, _Tpc __c, _Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote_3<_Tpa, _Tpc, _Tp>::__type __type;
+      return __detail::__conf_hyperg<__type>(__a, __c, __x);
+    }
+
+  inline float
+  hypergf(float __a, float __b, float __c, float __x)
+  { return __detail::__hyperg<float>(__a, __b, __c, __x); }
+
+  inline long double
+  hypergl(long double __a, long double __b, long double __c, long double __x)
+  { return __detail::__hyperg<long double>(__a, __b, __c, __x); }
+
+  ///  5.2.1.17  Hypergeometric functions.
+  template<typename _Tpa, typename _Tpb, typename _Tpc, typename _Tp>
+    inline typename __gnu_cxx::__promote_4<_Tpa, _Tpb, _Tpc, _Tp>::__type
+    hyperg(_Tpa __a, _Tpb __b, _Tpc __c, _Tp __x)
+    {
+      typedef typename __gnu_cxx::__promote_4<_Tpa, _Tpb, _Tpc, _Tp>::__type __type;
+      return __detail::__hyperg<__type>(__a, __b, __c, __x);
+    }
+
+} // namespace tr1
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // _GLIBCXX_USE_STD_SPEC_FUNCS && !defined(__STRICT_ANSI__)
+
 #endif // _GLIBCXX_TR1_CMATH
diff --git a/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/07_conf_hyperg/compile_cxx17.cc b/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/07_conf_hyperg/compile_cxx17.cc
new file mode 100644
index 00000000000..f0b0f96af27
--- /dev/null
+++ b/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/07_conf_hyperg/compile_cxx17.cc
@@ -0,0 +1,31 @@ 
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=c++17" }
+// { dg-do compile { target c++17 } }
+
+#include <tr1/cmath>
+
+void
+test01()
+{
+  // For C++17 most TR1 special functions re-use the C++17 functions
+  // in namespace std, but in strict -std=c++17 mode the hypergeometric
+  // functions are not defined in namespace std. This test ensures they
+  // are still available in namespace std::tr1.
+  (void) std::tr1::conf_hyperg(1.0, 2.0, 3.0);
+}
diff --git a/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/17_hyperg/compile_cxx17.cc b/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/17_hyperg/compile_cxx17.cc
new file mode 100644
index 00000000000..048328b6c00
--- /dev/null
+++ b/libstdc++-v3/testsuite/tr1/5_numerical_facilities/special_functions/17_hyperg/compile_cxx17.cc
@@ -0,0 +1,31 @@ 
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=c++17" }
+// { dg-do compile { target c++17 } }
+
+#include <tr1/cmath>
+
+void
+test01()
+{
+  // For C++17 most TR1 special functions re-use the C++17 functions
+  // in namespace std, but in strict -std=c++17 mode the hypergeometric
+  // functions are not defined in namespace std. This test ensures they
+  // are still available in namespace std::tr1.
+  (void) std::tr1::hyperg(1.0, 2.0, 3.0, 4.0);
+}