Add feature test macro for atomic<T>::wait

Adds __cpp_lib_atomic_wait feature test macro which was overlooked in
the initial commit of this feature. Replaces uses of
_GLIBCXX_HAVE_ATOMIC_WAIT.

libstdc++-v3/ChangeLog:

	* include/bits/atomic_base.h: Replace usage of
	_GLIBCXX_HAVE_ATOMIC_WAIT with __cpp_lib_atomic_wait.
	* include/bits/atomic_timed_wait.h: Likewise.
	* include/bits/atomic_wait.h: Define __cpp_lib_atomic_wait
	feature test macro.
	* include/bits/semaphore_base.h: Replace usage of
	_GLIBCXX_HAVE_ATOMIC_WAIT with __cpp_lib_atomic_wait.
	* include/std/atomic: Likewise.
	* include/std/latch: Likewise.
	* include/std/semaphore: Likewise.
	* include/std/version: Define __cpp_lib_atomic wait
	feature test macro and replace usage of
	_GLIBCXX_HAVE_ATOMIC_WAIT.
	* testsuite/29_atomics/atomic/wait_notify/1.cc: New test.
	* testsuite/29_atomics/atomic/wait_notify/2.cc: Likewise.

10 files changed, 100 insertions, 38 deletions

diff --git a/libstdc++-v3/include/bits/atomic_base.h b/libstdc++-v3/include/bits/atomic_base.h
index d0d962d..89f66a2 100644
--- a/libstdc++-v3/include/bits/atomic_base.h
+++ b/libstdc++-v3/include/bits/atomic_base.h
@@ -230,7 +230,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       return __v == __GCC_ATOMIC_TEST_AND_SET_TRUEVAL;
     }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
     _GLIBCXX_ALWAYS_INLINE void
     wait(bool __old,
 	memory_order __m = memory_order_seq_cst) const noexcept
@@ -253,7 +253,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     { std::__atomic_notify(&_M_i, true); }
 
     // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 #endif // C++20
 
     _GLIBCXX_ALWAYS_INLINE void
@@ -604,7 +604,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__m));
       }
 
-#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(__int_type __old,
 	  memory_order __m = memory_order_seq_cst) const noexcept
@@ -627,7 +627,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { std::__atomic_notify(&_M_i, true); }
 
       // TODO add const volatile overload
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
       _GLIBCXX_ALWAYS_INLINE __int_type
       fetch_add(__int_type __i,
@@ -898,7 +898,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					   int(__m1), int(__m2));
       }
 
-#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(__pointer_type __old,
 	   memory_order __m = memory_order_seq_cst) noexcept
@@ -921,7 +921,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { std::__atomic_notify(&_M_p, true); }
 
       // TODO add const volatile overload
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
       _GLIBCXX_ALWAYS_INLINE __pointer_type
       fetch_add(ptrdiff_t __d,
@@ -1011,7 +1011,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					 int(__success), int(__failure));
       }
 
-#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
     template<typename _Tp>
       _GLIBCXX_ALWAYS_INLINE void
       wait(const _Tp* __ptr, _Val<_Tp> __old,
@@ -1036,7 +1036,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { std::__atomic_notify(__ptr, true); }
 
       // TODO add const volatile overload
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
     template<typename _Tp>
       _GLIBCXX_ALWAYS_INLINE _Tp
@@ -1291,7 +1291,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__order));
       }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
       { __atomic_impl::wait(&_M_fp, __old, __m); }
@@ -1309,7 +1309,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { __atomic_impl::notify_all(&_M_fp); }
 
       // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
       value_type
       fetch_add(value_type __i,
@@ -1448,7 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__order));
       }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
       { __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1466,7 +1466,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { __atomic_impl::notify_all(_M_ptr); }
 
       // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
     private:
       _Tp* _M_ptr;
@@ -1563,7 +1563,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__order));
       }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
       { __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1581,7 +1581,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { __atomic_impl::notify_all(_M_ptr); }
 
       // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait 
 
       value_type
       fetch_add(value_type __i,
@@ -1738,7 +1738,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__order));
       }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
       { __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1756,7 +1756,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { __atomic_impl::notify_all(_M_ptr); }
 
       // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
       value_type
       fetch_add(value_type __i,
@@ -1867,7 +1867,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 				       __cmpexch_failure_order(__order));
       }
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
       _GLIBCXX_ALWAYS_INLINE void
       wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
       { __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1885,7 +1885,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { __atomic_impl::notify_all(_M_ptr); }
 
       // TODO add const volatile overload
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
       _GLIBCXX_ALWAYS_INLINE value_type
       fetch_add(difference_type __d,
diff --git a/libstdc++-v3/include/bits/atomic_timed_wait.h b/libstdc++-v3/include/bits/atomic_timed_wait.h
index f3a07a3..6dd1a14 100644
--- a/libstdc++-v3/include/bits/atomic_timed_wait.h
+++ b/libstdc++-v3/include/bits/atomic_timed_wait.h
@@ -33,7 +33,8 @@
 #pragma GCC system_header
 
 #include <bits/atomic_wait.h>
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+
+#ifdef __cpp_lib_atomic_wait
 #include <bits/functional_hash.h>
 
 #include <chrono>
@@ -292,5 +293,5 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     }
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 #endif // _GLIBCXX_ATOMIC_TIMED_WAIT_H
diff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h
index a59ed8c..5efd96d 100644
--- a/libstdc++-v3/include/bits/atomic_wait.h
+++ b/libstdc++-v3/include/bits/atomic_wait.h
@@ -50,8 +50,7 @@
 # include <bits/std_mutex.h>  // std::mutex, std::__condvar
 #endif
 
-// Other headers use this to check for the facilities defined in this header.
-#define _GLIBCXX_HAVE_ATOMIC_WAIT 1
+#define __cpp_lib_atomic_wait 201907L
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
diff --git a/libstdc++-v3/include/bits/semaphore_base.h b/libstdc++-v3/include/bits/semaphore_base.h
index f298423..0ed1f58 100644
--- a/libstdc++-v3/include/bits/semaphore_base.h
+++ b/libstdc++-v3/include/bits/semaphore_base.h
@@ -33,7 +33,7 @@
 #pragma GCC system_header
 
 #include <bits/atomic_base.h>
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#ifdef __cpp_lib_atomic_wait 
 #include <bits/atomic_timed_wait.h>
 
 #include <ext/numeric_traits.h>
@@ -297,5 +297,5 @@ template<ptrdiff_t __least_max_value>
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 #endif // _GLIBCXX_SEMAPHORE_BASE_H
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index 664af02..4a9b001 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -164,7 +164,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		    memory_order __m = memory_order_seq_cst) volatile noexcept
     { return _M_base.compare_exchange_strong(__i1, __i2, __m); }
 
-#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
     void
     wait(bool __old, memory_order __m = memory_order_seq_cst) const noexcept
     { _M_base.wait(__old, __m); }
@@ -178,7 +178,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     void
     notify_all() const noexcept
     { _M_base.notify_all(); }
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
   };
 
 #if __cplusplus <= 201703L
@@ -380,7 +380,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { return compare_exchange_strong(__e, __i, __m,
                                        __cmpexch_failure_order(__m)); }
 
-#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait 
     void
     wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
     {
@@ -404,7 +404,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     void
     notify_all() const noexcept
     { std::__atomic_notify(&_M_i, true); }
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait 
 
     };
 #undef _GLIBCXX20_INIT
@@ -644,7 +644,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					    __cmpexch_failure_order(__m));
       }
 
-#if __cplusplus > 201703L && _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait 
     void
     wait(__pointer_type __old, memory_order __m = memory_order_seq_cst) noexcept
     { _M_b.wait(__old, __m); }
@@ -658,7 +658,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     void
     notify_all() const noexcept
     { _M_b.notify_all(); }
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
       __pointer_type
       fetch_add(ptrdiff_t __d,
 		memory_order __m = memory_order_seq_cst) noexcept
@@ -1412,7 +1412,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     }
 
 
-#if __cplusplus > 201703L && _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
   template<typename _Tp>
     inline void
     atomic_wait(const atomic<_Tp>* __a,
@@ -1435,7 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     inline void
     atomic_notify_all(atomic<_Tp>* __a) noexcept
     { __a->notify_all(); }
-#endif // C++20 && HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 
   // Function templates for atomic_integral and atomic_pointer operations only.
   // Some operations (and, or, xor) are only available for atomic integrals,
diff --git a/libstdc++-v3/include/std/latch b/libstdc++-v3/include/std/latch
index 2684b72..d4a00c4 100644
--- a/libstdc++-v3/include/std/latch
+++ b/libstdc++-v3/include/std/latch
@@ -36,7 +36,7 @@
 #include <bits/atomic_base.h>
 #include <ext/numeric_traits.h>
 
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
 namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -89,6 +89,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   };
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 #endif // __cplusplus > 201703L
 #endif // _GLIBCXX_LATCH
diff --git a/libstdc++-v3/include/std/semaphore b/libstdc++-v3/include/std/semaphore
index 184c7c2..ff83a56 100644
--- a/libstdc++-v3/include/std/semaphore
+++ b/libstdc++-v3/include/std/semaphore
@@ -33,7 +33,7 @@
 
 #if __cplusplus > 201703L
 #include <bits/semaphore_base.h>
-#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#if __cpp_lib_atomic_wait
 #include <ext/numeric_traits.h>
 
 namespace std _GLIBCXX_VISIBILITY(default)
@@ -90,6 +90,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
  using binary_semaphore = std::counting_semaphore<1>;
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace
-#endif // HAVE_ATOMIC_WAIT
+#endif // __cpp_lib_atomic_wait
 #endif // C++20
 #endif // _GLIBCXX_SEMAPHORE
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 0f2da8a..4bb45b7 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -197,6 +197,9 @@
 #if _GLIBCXX_HOSTED
 #define __cpp_lib_array_constexpr 201811L
 #define __cpp_lib_assume_aligned 201811L
+#if defined _GLIBCXX_HAS_GTHREADS || defined _GLIBCXX_HAVE_LINUX_FUTEX
+# define __cpp_lib_atomic_wait 201907L
+#endif
 #define __cpp_lib_bind_front 201907L
 // FIXME: #define __cpp_lib_execution 201902L
 #define __cpp_lib_integer_comparison_functions 202002L
@@ -216,7 +219,7 @@
 #ifdef _GLIBCXX_HAS_GTHREADS
 # define __cpp_lib_jthread 201911L
 #endif
-#if defined _GLIBCXX_HAS_GTHREADS || defined _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cpp_lib_atomic_wait 
 # define __cpp_lib_latch 201907L
 #endif
 #define __cpp_lib_list_remove_return_type 201806L
@@ -228,7 +231,7 @@
 #if __cpp_lib_concepts
 # define __cpp_lib_ranges 201911L
 #endif
-#if defined _GLIBCXX_HAS_GTHREADS || defined _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cpp_lib_atomic_wait 
 # define __cpp_lib_semaphore 201907L
 #endif
 #define __cpp_lib_shift 201806L
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/1.cc b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/1.cc
new file mode 100644
index 0000000..7b183b2
--- /dev/null
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/1.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2020 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=gnu++2a" }
+// { dg-do compile { target c++2a } }
+// { dg-require-effective-target gthreads }
+
+#include <atomic>
+
+#ifndef __cpp_lib_atomic_wait
+# error "Feature-test macro for atomic wait missing in <atomic>"
+#elif __cpp_lib_atomic_wait != 201907L
+# error "Feature-test macro for atomic wait has wrong value in <atomic>"
+#endif
+
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/2.cc b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/2.cc
new file mode 100644
index 0000000..249bf2d
--- /dev/null
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/wait_notify/2.cc
@@ -0,0 +1,30 @@
+// Copyright (C) 2020 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=gnu++2a" }
+// { dg-do compile { target c++2a } }
+// { dg-require-effective-target gthreads }
+
+#include <version>
+
+#ifndef __cpp_lib_atomic_wait
+# error "Feature-test macro for atomic wait missing in <version>"
+#elif __cpp_lib_atomic_wait != 201907L
+# error "Feature-test macro for atomic wait has wrong value in <version>"
+#endif
+
+