diff mbox

libstdc++: Allow using <future> without lock free atomic int

Message ID 20161219175227.GP895@redhat.com
State New
Headers show

Commit Message

Jonathan Wakely Dec. 19, 2016, 5:52 p.m. UTC 
On 16/12/16 17:52 +0000, Jonathan Wakely wrote:
>On 09/11/16 23:26 +0200, Pauli wrote:

>>Compiling programs using std::future for old arm processors fails. The

>>problem is caused by preprocessor check for atomic lock free int.

>>

>>Future can be changed to work correctly without lock free atomics with

>>minor changes to exception_ptr implementation.

>>

>>Without lock free atomics there is question if deadlock can happen. But

>>atomic operations can't call outside code preventing any ABBA or

>>recursive mutex acquiring deadlocks.

>>Deadlock could happen if throwing an exception or access

>>is_lock_free() == false atomic from asynchronous signal handler.

>>Throwing from signal handler is undefined behavior. I don't know about

>>accessing atomics from asynchronous signal handler but that feels like

>>undefined behavior if is_lock_free returns false.

>>

>>Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64735

>>

>>differences to current if atomic builtins available:

>>* Race detector annotations that are empty by default

>>* Check for __gthread_active_p

>>* Generate x86 code uses xadd instead of xsub

>>This makes code a bit worse. But problem is duplicated to any other user

>>of __exchange_and_add. The internal API implementation should be fixed

>>to generate better code for all cases. But that is a follow up patch.

>

>I'd prefer to do it so we don't change anything for the targets that

>already work. Your follow-up patch missed the deadline for GCC 7 and

>so will have to wait for GCC 8 now, and we don't want to pessimize

>x86.

>

>Also, I think your patch actually breaks some GNU/Linux targets,

>because you removed the <atomic_lockfree_defines.h> header from

><exception>, which means that in libsupc++/guard.cc the macro

>ATOMIC_INT_LOCK_FREE is no longer defined, and so _GLIBCXX_USE_FUTEX

>doesn't get defined. Now arguably guard.cc should have been including

>the header directly, but it still shows why such an invasive patch is

>a bad idea at this stage of the GCC 7 process.

>

>The attached patch attempts to make exception propagation work for all

>targets, without changing anything if it already works.

>

>Do you see any problems with this alternative approach?

>Could you please test it for armv5te?

>

>It passes all tests for x86_64-linux and ppc64le-linux.

>

>For your follow-up patch, do you already have a copyright assignment

>for contributions to GCC? We'll probably need that before it can be

>accepted. We don't need one for this patch, because what remains of

>your original patch is just the testsuite changes, which are

>mechanical and not copyrightable.


We also need to adjust the linker script to avoid adding new exports
to old symbol versions, revised patch attached. I think it would be
better to make configure define a macro like
HAVE_EXCEPTION_PTR_SINCE_GCC6 and use that in the linker script
instead of testing __GCC_ATOMIC_INT_LOCK_FREE directly. I'll work on
that.
diff mbox

Patch

commit a19855aecf301a30bb1d6f6c39fe2a458baddd48
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Dec 16 15:22:21 2016 +0000

    PR64735 support exception propagation without atomics
    
    2016-12-19  Pauli Nieminen  <suokkos@gmail.com>
    	    Jonathan Wakely  <jwakely@redhat.com>
    
    	PR libstdc++/64735
    	* config/abi/pre/gnu.ver [__GCC_ATOMIC_INT_LOCK_FREE > 1]
    	(GLIBCXX_3.4.15, GLIBCXX_3.4.21, CXXABI_1.3.3, CXXABI_1.3.5): Make
    	exports for exception_ptr, nested_exception, and future conditional.
    	[__GCC_ATOMIC_INT_LOCK_FREE <= 1] (GLIBCXX_3.4.23, CXXABI_1.3.11): Add
    	exports for exception_ptr, nested_exception, and future conditional.
    	* include/std/future: Remove check for ATOMIC_INT_LOCK_FREE
    	* libsupc++/eh_atomics.h: New file for internal use only.
    	(__eh_atomic_inc, __eh_atomic_dec): New.
    	* libsupc++/eh_ptr.cc (exception_ptr::_M_addref)
    	(exception_ptr::_M_release) (__gxx_dependent_exception_cleanup)
    	(rethrow_exception): Use eh_atomics.h reference counting helpers.
    	* libsupc++/eh_throw.cc (__gxx_exception_cleanup): Likewise.
    	* libsupc++/eh_tm.cc (free_any_cxa_exception): Likewise.
    	* libsupc++/exception: Remove check for ATOMIC_INT_LOCK_FREE.
    	* libsupc++/exception_ptr.h: Likewise.
    	* libsupc++/guard.cc: Include header for ATOMIC_INT_LOCK_FREE macro.
    	* libsupc++/nested_exception.cc: Remove check for
    	ATOMIC_INT_LOCK_FREE.
    	* libsupc++/nested_exception.h: Likewise.
    	* src/c++11/future.cc: Likewise.
    	* testsuite/18_support/exception_ptr/*: Remove atomic builtins checks.
    	* testsuite/18_support/nested_exception/*: Likewise.
    	* testsuite/30_threads/async/*: Likewise.
    	* testsuite/30_threads/future/*: Likewise.
    	* testsuite/30_threads/headers/future/types_std_c++0x.cc: Likewise.
    	* testsuite/30_threads/packaged_task/*: Likewise.
    	* testsuite/30_threads/promise/*: Likewise.
    	* testsuite/30_threads/shared_future/*: Likewise.

diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index 8b0f67b..5da698e 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -1503,6 +1503,9 @@  GLIBCXX_3.4.15 {
     _ZNSt14error_categoryC*;
     _ZNSt14error_categoryD*;
 
+#if __GCC_ATOMIC_INT_LOCK_FREE > 1
+    # std::future symbols are only present in this version when
+    # atomic operations on int are always lock-free.
     _ZNSt13__future_base12_Result_baseC*;
     _ZNSt13__future_base12_Result_baseD*;
     _ZTINSt13__future_base12_Result_baseE;
@@ -1511,6 +1514,7 @@  GLIBCXX_3.4.15 {
     _ZNSt13__future_base11_State_baseD*;
     _ZTINSt13__future_base11_State_baseE;
     _ZTVNSt13__future_base11_State_baseE;
+#endif
 
 } GLIBCXX_3.4.14;
 
@@ -1687,8 +1691,10 @@  GLIBCXX_3.4.21 {
 
     # std::notify_all_at_thread_exit
     _ZSt25notify_all_at_thread_exitRSt18condition_variableSt11unique_lockISt5mutexE;
+#if __GCC_ATOMIC_INT_LOCK_FREE > 1
     # std::__future_base::_State_baseV2::_Make_ready::_M_set()
     _ZNSt13__future_base13_State_baseV211_Make_ready6_M_setEv;
+#endif
 
     # ABI-tagged std::basic_string
     _ZNSt7__cxx1112basic_stringI[cw]St11char_traitsI[cw]ESaI[cw]EE1[01]**;
@@ -1947,6 +1953,16 @@  GLIBCXX_3.4.23 {
     _ZNSsC[12]ERKSs[jmy]RKSaIcE;
     _ZNSbIwSt11char_traitsIwESaIwEEC[12]ERKS2_mRKS1_;
 
+#if __GCC_ATOMIC_INT_LOCK_FREE <= 1
+    # std::future symbols were first exported for this version
+    # when atomic operations on int are not always lock-free.
+    _ZNSt13__future_base12_Result_baseC*;
+    _ZNSt13__future_base12_Result_baseD*;
+    _ZTINSt13__future_base12_Result_baseE;
+    _ZTVNSt13__future_base12_Result_baseE;
+    _ZNSt13__future_base13_State_baseV211_Make_ready6_M_setEv;
+#endif
+
 } GLIBCXX_3.4.22;
 
 # Symbols in the support library (libsupc++) have their own tag.
@@ -2080,6 +2096,7 @@  CXXABI_1.3.3 {
     _ZTIPDi;
     _ZTIPKDi;
 
+#if __GCC_ATOMIC_INT_LOCK_FREE > 1
     # exception_ptr
     _ZNSt15__exception_ptr13exception_ptrC1Ev;
     _ZNSt15__exception_ptr13exception_ptrC2Ev;
@@ -2099,6 +2116,7 @@  CXXABI_1.3.3 {
 
     _ZSt17current_exceptionv;
     _ZSt17rethrow_exceptionNSt15__exception_ptr13exception_ptrE;
+#endif
 
 } CXXABI_1.3.2;
 
@@ -2129,10 +2147,12 @@  CXXABI_1.3.5 {
     # FNV hash.
     _ZSt15_Fnv_hash_bytesPKv*;
 
+#if __GCC_ATOMIC_INT_LOCK_FREE > 1
     # std::nested_exception
     _ZNSt16nested_exceptionD*;
     _ZTISt16nested_exception;
     _ZTVSt16nested_exception;
+#endif
 
 } CXXABI_1.3.4;
 
@@ -2209,6 +2229,33 @@  CXXABI_1.3.11 {
     _ZdaPvSt11align_val_tRKSt9nothrow_t;
     _ZdaPv[jmy]St11align_val_t;
 
+#if __GCC_ATOMIC_INT_LOCK_FREE <= 1
+    # exception_ptr
+    _ZNSt15__exception_ptr13exception_ptrC1Ev;
+    _ZNSt15__exception_ptr13exception_ptrC2Ev;
+    _ZNSt15__exception_ptr13exception_ptrC1ERKS0_;
+    _ZNSt15__exception_ptr13exception_ptrC2ERKS0_;
+    _ZNSt15__exception_ptr13exception_ptrC1EMS0_FvvE;
+    _ZNSt15__exception_ptr13exception_ptrC2EMS0_FvvE;
+    _ZNSt15__exception_ptr13exception_ptrD1Ev;
+    _ZNSt15__exception_ptr13exception_ptrD2Ev;
+    _ZNSt15__exception_ptr13exception_ptraSERKS0_;
+    _ZNKSt15__exception_ptr13exception_ptrcvMS0_FvvEEv;
+    _ZNKSt15__exception_ptr13exception_ptrntEv;
+    _ZNKSt15__exception_ptr13exception_ptr20__cxa_exception_typeEv;
+    _ZNSt15__exception_ptr13exception_ptr4swapERS0_;
+    _ZNSt15__exception_ptreqERKNS_13exception_ptrES2_;
+    _ZNSt15__exception_ptrneERKNS_13exception_ptrES2_;
+
+    _ZSt17current_exceptionv;
+    _ZSt17rethrow_exceptionNSt15__exception_ptr13exception_ptrE;
+
+    # std::nested_exception
+    _ZNSt16nested_exceptionD*;
+    _ZTISt16nested_exception;
+    _ZTVSt16nested_exception;
+#endif
+
 } CXXABI_1.3.10;
 
 # Symbols in the support library (libsupc++) supporting transactional memory.
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future
index 8ba1306..b83d74b 100644
--- a/libstdc++-v3/include/std/future
+++ b/libstdc++-v3/include/std/future
@@ -192,8 +192,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     future<__async_result_of<_Fn, _Args...>>
     async(_Fn&& __fn, _Args&&... __args);
 
-#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \
-  && (ATOMIC_INT_LOCK_FREE > 1)
+#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
 
   /// Base class and enclosing scope.
   struct __future_base
@@ -1751,7 +1750,6 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #endif // _GLIBCXX_ASYNC_ABI_COMPAT
 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
-       // && ATOMIC_INT_LOCK_FREE
 
   // @} group futures
 _GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/libsupc++/eh_atomics.h b/libstdc++-v3/libsupc++/eh_atomics.h
new file mode 100644
index 0000000..71b42a4
--- /dev/null
+++ b/libstdc++-v3/libsupc++/eh_atomics.h
@@ -0,0 +1,84 @@ 
+// Exception Handling support header for -*- C++ -*-
+
+// Copyright (C) 2016 Free Software Foundation, Inc.
+//
+// This file is part of GCC.
+//
+// GCC 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.
+//
+// GCC 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.
+//
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file eh_atomics.h
+ *  This is an internal header file, included by library source files.
+ *  Do not attempt to use it directly.
+ */
+
+#ifndef _EH_ATOMICS_H
+#define _EH_ATOMICS_H 1
+
+#include <bits/c++config.h>
+#include <bits/atomic_word.h>
+#include <bits/atomic_lockfree_defines.h>
+#if ATOMIC_INT_LOCK_FREE <= 1
+# include <ext/atomicity.h>
+#endif
+
+#pragma GCC visibility push(default)
+extern "C++" {
+namespace __gnu_cxx
+{
+  void
+  __eh_atomic_inc (_Atomic_word* __count) __attribute__((always_inline));
+
+  bool
+  __eh_atomic_dec (_Atomic_word* __count) __attribute__((always_inline));
+
+  // Increments the count.
+  inline void
+  __eh_atomic_inc (_Atomic_word* __count)
+  {
+#if ATOMIC_INT_LOCK_FREE > 1
+    __atomic_add_fetch (__count, 1, __ATOMIC_ACQ_REL);
+#else
+    _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
+    __gnu_cxx::__atomic_add_dispatch (__count, 1);
+    _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
+#endif
+  }
+
+  // Decrements the count and returns true if it reached zero.
+  inline bool
+  __eh_atomic_dec (_Atomic_word* __count)
+  {
+#if ATOMIC_INT_LOCK_FREE > 1
+    return __atomic_sub_fetch (__count, 1, __ATOMIC_ACQ_REL) == 0;
+#else
+    _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
+    if (__gnu_cxx::__exchange_and_add_dispatch (__count, -1) == 1)
+      {
+	_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
+	return true;
+      }
+    return false;
+#endif
+  }
+} // namespace __gnu_cxx
+}
+#pragma GCC visibility pop
+
+#endif // _EH_ATOMICS_H
diff --git a/libstdc++-v3/libsupc++/eh_ptr.cc b/libstdc++-v3/libsupc++/eh_ptr.cc
index f3c910b..33e3a21 100644
--- a/libstdc++-v3/libsupc++/eh_ptr.cc
+++ b/libstdc++-v3/libsupc++/eh_ptr.cc
@@ -23,9 +23,7 @@ 
 // <http://www.gnu.org/licenses/>.
 
 #include <bits/c++config.h>
-#include <bits/atomic_lockfree_defines.h>
-
-#if ATOMIC_INT_LOCK_FREE > 1
+#include "eh_atomics.h"
 
 #define _GLIBCXX_EH_PTR_COMPAT
 
@@ -101,7 +99,7 @@  std::__exception_ptr::exception_ptr::_M_addref() noexcept
     {
       __cxa_refcounted_exception *eh =
 	__get_refcounted_exception_header_from_obj (_M_exception_object);
-      __atomic_add_fetch (&eh->referenceCount, 1, __ATOMIC_ACQ_REL);
+      __gnu_cxx::__eh_atomic_inc (&eh->referenceCount);
     }
 }
 
@@ -113,7 +111,7 @@  std::__exception_ptr::exception_ptr::_M_release() noexcept
     {
       __cxa_refcounted_exception *eh =
 	__get_refcounted_exception_header_from_obj (_M_exception_object);
-      if (__atomic_sub_fetch (&eh->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
+      if (__gnu_cxx::__eh_atomic_dec (&eh->referenceCount))
         {
 	  if (eh->exc.exceptionDestructor)
 	    eh->exc.exceptionDestructor (_M_exception_object);
@@ -211,7 +209,7 @@  __gxx_dependent_exception_cleanup(_Unwind_Reason_Code code,
 
   __cxa_free_dependent_exception (dep);
 
-  if (__atomic_sub_fetch (&header->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
+  if (__gnu_cxx::__eh_atomic_dec (&header->referenceCount))
     {
       if (header->exc.exceptionDestructor)
 	header->exc.exceptionDestructor (header + 1);
@@ -230,7 +228,7 @@  std::rethrow_exception(std::exception_ptr ep)
 
   __cxa_dependent_exception *dep = __cxa_allocate_dependent_exception ();
   dep->primaryException = obj;
-  __atomic_add_fetch (&eh->referenceCount, 1,  __ATOMIC_ACQ_REL);
+  __gnu_cxx::__eh_atomic_inc (&eh->referenceCount);
 
   dep->unexpectedHandler = get_unexpected ();
   dep->terminateHandler = get_terminate ();
@@ -252,5 +250,3 @@  std::rethrow_exception(std::exception_ptr ep)
 }
 
 #undef _GLIBCXX_EH_PTR_COMPAT
-
-#endif
diff --git a/libstdc++-v3/libsupc++/eh_throw.cc b/libstdc++-v3/libsupc++/eh_throw.cc
index a05f4eb..0174a93 100644
--- a/libstdc++-v3/libsupc++/eh_throw.cc
+++ b/libstdc++-v3/libsupc++/eh_throw.cc
@@ -24,6 +24,7 @@ 
 
 #include <bits/c++config.h>
 #include "unwind-cxx.h"
+#include "eh_atomics.h"
 
 using namespace __cxxabiv1;
 
@@ -42,17 +43,13 @@  __gxx_exception_cleanup (_Unwind_Reason_Code code, _Unwind_Exception *exc)
   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
     __terminate (header->exc.terminateHandler);
 
-#if ATOMIC_INT_LOCK_FREE > 1
-  if (__atomic_sub_fetch (&header->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
+  if (__gnu_cxx::__eh_atomic_dec (&header->referenceCount))
     {
-#endif
       if (header->exc.exceptionDestructor)
 	header->exc.exceptionDestructor (header + 1);
 
       __cxa_free_exception (header + 1);
-#if ATOMIC_INT_LOCK_FREE > 1
     }
-#endif
 }
 
 extern "C" __cxa_refcounted_exception*
diff --git a/libstdc++-v3/libsupc++/eh_tm.cc b/libstdc++-v3/libsupc++/eh_tm.cc
index c05f611..85ae46c 100644
--- a/libstdc++-v3/libsupc++/eh_tm.cc
+++ b/libstdc++-v3/libsupc++/eh_tm.cc
@@ -24,6 +24,7 @@ 
 
 #include <cstdlib>
 #include "unwind-cxx.h"
+#include "eh_atomics.h"
 
 using namespace __cxxabiv1;
 
@@ -45,9 +46,7 @@  free_any_cxa_exception (_Unwind_Exception *eo)
       __cxa_free_dependent_exception (dep);
     }
 
-#if __GCC_ATOMIC_INT_LOCK_FREE > 1
-  if (__atomic_sub_fetch (&h->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
-#endif
+  if (__gnu_cxx::__eh_atomic_dec (&h->referenceCount))
     __cxa_free_exception (h + 1);
 }
 
diff --git a/libstdc++-v3/libsupc++/exception b/libstdc++-v3/libsupc++/exception
index 8be903b..021d70e 100644
--- a/libstdc++-v3/libsupc++/exception
+++ b/libstdc++-v3/libsupc++/exception
@@ -35,7 +35,6 @@ 
 #pragma GCC visibility push(default)
 
 #include <bits/c++config.h>
-#include <bits/atomic_lockfree_defines.h>
 #include <bits/exception.h>
 
 extern "C++" {
@@ -139,7 +138,7 @@  _GLIBCXX_END_NAMESPACE_VERSION
 
 #pragma GCC visibility pop
 
-#if (__cplusplus >= 201103L) && (ATOMIC_INT_LOCK_FREE > 1)
+#if (__cplusplus >= 201103L)
 #include <bits/exception_ptr.h>
 #include <bits/nested_exception.h>
 #endif
diff --git a/libstdc++-v3/libsupc++/exception_ptr.h b/libstdc++-v3/libsupc++/exception_ptr.h
index a47a585..cce156a 100644
--- a/libstdc++-v3/libsupc++/exception_ptr.h
+++ b/libstdc++-v3/libsupc++/exception_ptr.h
@@ -39,10 +39,6 @@ 
 #include <typeinfo>
 #include <new>
 
-#if ATOMIC_INT_LOCK_FREE < 2
-#  error This platform does not support exception propagation.
-#endif
-
 extern "C++" {
 
 namespace std 
diff --git a/libstdc++-v3/libsupc++/guard.cc b/libstdc++-v3/libsupc++/guard.cc
index 9b61799..66edffb 100644
--- a/libstdc++-v3/libsupc++/guard.cc
+++ b/libstdc++-v3/libsupc++/guard.cc
@@ -30,6 +30,7 @@ 
 #include <new>
 #include <ext/atomicity.h>
 #include <ext/concurrence.h>
+#include <bits/atomic_lockfree_defines.h>
 #if defined(__GTHREADS) && defined(__GTHREAD_HAS_COND) \
   && (ATOMIC_INT_LOCK_FREE > 1) && defined(_GLIBCXX_HAVE_LINUX_FUTEX)
 # include <climits>
diff --git a/libstdc++-v3/libsupc++/nested_exception.cc b/libstdc++-v3/libsupc++/nested_exception.cc
index c1a7b7a..82dddb1 100644
--- a/libstdc++-v3/libsupc++/nested_exception.cc
+++ b/libstdc++-v3/libsupc++/nested_exception.cc
@@ -25,7 +25,5 @@ 
 
 namespace std 
 {
-#if ATOMIC_INT_LOCK_FREE > 1
   nested_exception::~nested_exception() noexcept = default;
-#endif
 } // namespace std
diff --git a/libstdc++-v3/libsupc++/nested_exception.h b/libstdc++-v3/libsupc++/nested_exception.h
index 078af0e..48bdabb 100644
--- a/libstdc++-v3/libsupc++/nested_exception.h
+++ b/libstdc++-v3/libsupc++/nested_exception.h
@@ -39,10 +39,6 @@ 
 #include <bits/c++config.h>
 #include <bits/move.h>
 
-#if ATOMIC_INT_LOCK_FREE < 2
-#  error This platform does not support exception propagation.
-#endif
-
 extern "C++" {
 
 namespace std
diff --git a/libstdc++-v3/src/c++11/future.cc b/libstdc++-v3/src/c++11/future.cc
index 7809a37..a14051a 100644
--- a/libstdc++-v3/src/c++11/future.cc
+++ b/libstdc++-v3/src/c++11/future.cc
@@ -78,8 +78,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   const char*
   future_error::what() const noexcept { return logic_error::what(); }
 
-#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \
-  && (ATOMIC_INT_LOCK_FREE > 1)
+#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
   __future_base::_Result_base::_Result_base() = default;
 
   __future_base::_Result_base::~_Result_base() = default;
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/40296.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/40296.cc
index 74307cc..a6659b8 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/40296.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/40296.cc
@@ -1,5 +1,4 @@ 
 // { dg-do compile { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/60612-terminate.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/60612-terminate.cc
index c00e287..d58f32d 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/60612-terminate.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/60612-terminate.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/60612-unexpected.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/60612-unexpected.cc
index 2b5ec2d..cfaea5d4 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/60612-unexpected.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/60612-unexpected.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/62258.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/62258.cc
index c83d5fb..5c15b48 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/62258.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/62258.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2015-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/64241.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/64241.cc
index c1e9a05..7dbf3d6 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/64241.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/64241.cc
@@ -17,7 +17,6 @@ 
 
 // { dg-options "-fno-exceptions -O0" }
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 #include <exception>
 #include <testsuite_hooks.h>
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/current_exception.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/current_exception.cc
index 79459eb..38decc1 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/current_exception.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/current_exception.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // 2008-05-25  Sebastian Redl  <sebastian.redl@getdesigned.at>
 
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/lifespan.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/lifespan.cc
index ada652e..8343b49 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/lifespan.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/lifespan.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // 2008-05-25  Sebastian Redl  <sebastian.redl@getdesigned.at>
 
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr.cc
index b9ded35..c35525e 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr_2.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr_2.cc
index 3787777..ad0333b 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr_2.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/make_exception_ptr_2.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/move.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/move.cc
index 6318bc4..80c6e3e 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/move.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/move.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/requirements.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/requirements.cc
index b3b9e0c..5f5f054 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/requirements.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/requirements.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/requirements_neg.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/requirements_neg.cc
index b80d688..95ec8ab 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/requirements_neg.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/requirements_neg.cc
@@ -1,5 +1,4 @@ 
 // { dg-do compile { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/exception_ptr/rethrow_exception.cc b/libstdc++-v3/testsuite/18_support/exception_ptr/rethrow_exception.cc
index 567af32..7f2ab93 100644
--- a/libstdc++-v3/testsuite/18_support/exception_ptr/rethrow_exception.cc
+++ b/libstdc++-v3/testsuite/18_support/exception_ptr/rethrow_exception.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // 2008-05-25  Sebastian Redl  <sebastian.redl@getdesigned.at>
 
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/51438.cc b/libstdc++-v3/testsuite/18_support/nested_exception/51438.cc
index 04ef32f..34728043 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/51438.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/51438.cc
@@ -1,5 +1,4 @@ 
 // { dg-do compile { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/62154.cc b/libstdc++-v3/testsuite/18_support/nested_exception/62154.cc
index f1884a5..124e4d1 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/62154.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/62154.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/68139.cc b/libstdc++-v3/testsuite/18_support/nested_exception/68139.cc
index bf803db..4164e91 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/68139.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/68139.cc
@@ -1,5 +1,4 @@ 
 // { dg-do compile { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2015-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/cons.cc b/libstdc++-v3/testsuite/18_support/nested_exception/cons.cc
index af6f90c..a1141b7 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/cons.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/cons.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/nested_ptr.cc b/libstdc++-v3/testsuite/18_support/nested_exception/nested_ptr.cc
index 467d371..c9092bd 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/nested_ptr.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/nested_ptr.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_if_nested.cc b/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_if_nested.cc
index b042084..62dd26a 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_if_nested.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_if_nested.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_nested.cc b/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_nested.cc
index fd374e5..c18f6f0 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_nested.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/rethrow_nested.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/18_support/nested_exception/throw_with_nested.cc b/libstdc++-v3/testsuite/18_support/nested_exception/throw_with_nested.cc
index f768b1e..3036328 100644
--- a/libstdc++-v3/testsuite/18_support/nested_exception/throw_with_nested.cc
+++ b/libstdc++-v3/testsuite/18_support/nested_exception/throw_with_nested.cc
@@ -1,5 +1,4 @@ 
 // { dg-do run { target c++11 } }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/42819.cc b/libstdc++-v3/testsuite/30_threads/async/42819.cc
index b836877..44cb674 100644
--- a/libstdc++-v3/testsuite/30_threads/async/42819.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/42819.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/49668.cc b/libstdc++-v3/testsuite/30_threads/async/49668.cc
index fe597c0..074d9b0 100644
--- a/libstdc++-v3/testsuite/30_threads/async/49668.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/49668.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/54297.cc b/libstdc++-v3/testsuite/30_threads/async/54297.cc
index 756fd97..ed9230d 100644
--- a/libstdc++-v3/testsuite/30_threads/async/54297.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/54297.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 // { dg-require-sleep "" }
 
 // Copyright (C) 2012-2016 Free Software Foundation, Inc.
diff --git a/libstdc++-v3/testsuite/30_threads/async/any.cc b/libstdc++-v3/testsuite/30_threads/async/any.cc
index a78b0e5..03c6401 100644
--- a/libstdc++-v3/testsuite/30_threads/async/any.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/any.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/async.cc b/libstdc++-v3/testsuite/30_threads/async/async.cc
index 02c497c..3de9ef6 100644
--- a/libstdc++-v3/testsuite/30_threads/async/async.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/async.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/except.cc b/libstdc++-v3/testsuite/30_threads/async/except.cc
index 1a63680..0d94916 100644
--- a/libstdc++-v3/testsuite/30_threads/async/except.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/except.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/forced_unwind.cc b/libstdc++-v3/testsuite/30_threads/async/forced_unwind.cc
index b344b74..c44fd29 100644
--- a/libstdc++-v3/testsuite/30_threads/async/forced_unwind.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/forced_unwind.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/launch.cc b/libstdc++-v3/testsuite/30_threads/async/launch.cc
index 7064c91..6ea6834 100644
--- a/libstdc++-v3/testsuite/30_threads/async/launch.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/launch.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/async/lwg2021.cc b/libstdc++-v3/testsuite/30_threads/async/lwg2021.cc
index 62fbf27..3a631e9 100644
--- a/libstdc++-v3/testsuite/30_threads/async/lwg2021.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/lwg2021.cc
@@ -20,7 +20,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // LWG 2021. Further incorrect usages of result_of
 // Arguments to result_of should use decay.
diff --git a/libstdc++-v3/testsuite/30_threads/async/sync.cc b/libstdc++-v3/testsuite/30_threads/async/sync.cc
index b4d47597..7fa11c8 100644
--- a/libstdc++-v3/testsuite/30_threads/async/sync.cc
+++ b/libstdc++-v3/testsuite/30_threads/async/sync.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/future/cons/assign_neg.cc
index a36dafb..467e7f0 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/assign_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/constexpr.cc b/libstdc++-v3/testsuite/30_threads/future/cons/constexpr.cc
index dcafe3e..b61ca13 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/constexpr.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/constexpr.cc
@@ -2,7 +2,6 @@ 
 // { dg-options "-fno-inline -g0" }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 // { dg-final { scan-assembler-not "_ZNSt6futureIvEC2Ev" } }
 // { dg-final { scan-assembler-not "_ZNSt6futureIiEC2Ev" } }
 
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/future/cons/copy_neg.cc
index 8fc5de6..f53056d 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/copy_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/default.cc b/libstdc++-v3/testsuite/30_threads/future/cons/default.cc
index b9424be..13c6e01 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/default.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/default.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/move.cc b/libstdc++-v3/testsuite/30_threads/future/cons/move.cc
index 63b017f..33d0b60 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/move.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/move.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/cons/move_assign.cc b/libstdc++-v3/testsuite/30_threads/future/cons/move_assign.cc
index 50971f3..910fe8e 100644
--- a/libstdc++-v3/testsuite/30_threads/future/cons/move_assign.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/cons/move_assign.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/45133.cc b/libstdc++-v3/testsuite/30_threads/future/members/45133.cc
index 1f91483..e5d63bd 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/45133.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/45133.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/get.cc b/libstdc++-v3/testsuite/30_threads/future/members/get.cc
index b99837e..849c94a 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/get.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/get.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/get2.cc b/libstdc++-v3/testsuite/30_threads/future/members/get2.cc
index 6a259e7..60bcb42 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/get2.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/get2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/share.cc b/libstdc++-v3/testsuite/30_threads/future/members/share.cc
index cb163e2..1933725 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/share.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/share.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/valid.cc b/libstdc++-v3/testsuite/30_threads/future/members/valid.cc
index e473dc1..5993a97 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/valid.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/valid.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/wait.cc b/libstdc++-v3/testsuite/30_threads/future/members/wait.cc
index 6d08243..6553890 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/wait.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/wait.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/wait_for.cc b/libstdc++-v3/testsuite/30_threads/future/members/wait_for.cc
index 1b8707d..457de4d 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/wait_for.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/wait_for.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/members/wait_until.cc b/libstdc++-v3/testsuite/30_threads/future/members/wait_until.cc
index ed71c50..0b54b8a 100644
--- a/libstdc++-v3/testsuite/30_threads/future/members/wait_until.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/members/wait_until.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/future/requirements/explicit_instantiation.cc b/libstdc++-v3/testsuite/30_threads/future/requirements/explicit_instantiation.cc
index 87d423f..592f03b 100644
--- a/libstdc++-v3/testsuite/30_threads/future/requirements/explicit_instantiation.cc
+++ b/libstdc++-v3/testsuite/30_threads/future/requirements/explicit_instantiation.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/headers/future/types_std_c++0x.cc b/libstdc++-v3/testsuite/30_threads/headers/future/types_std_c++0x.cc
index 3f9d273..c8f4e53 100644
--- a/libstdc++-v3/testsuite/30_threads/headers/future/types_std_c++0x.cc
+++ b/libstdc++-v3/testsuite/30_threads/headers/future/types_std_c++0x.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" } 
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/49668.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/49668.cc
index 1ab9d19..cb74ab8 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/49668.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/49668.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/60564.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/60564.cc
index f2f4ce9..d5c940b 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/60564.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/60564.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/1.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/1.cc
index ce8d6c1..2297d7dc 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/1.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/1.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/2.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/2.cc
index f267192..655aa40 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/2.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/3.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/3.cc
index 6903778..97d7d86 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/3.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/3.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/56492.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/56492.cc
index 718608e..b96ceb0 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/56492.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/56492.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2013-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc.cc
index c0830e3..7b7099d 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc2.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc2.cc
index ebfc00a..726f50a 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc2.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc2.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc_min.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc_min.cc
index e67f9fd..96f6631 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc_min.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/alloc_min.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
index 1c88262..4b9cbb5 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
index 7f1156f..05de5c6 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move.cc
index 1fa2d77..f654647 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move_assign.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move_assign.cc
index 2ee5018..377b29f 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move_assign.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/move_assign.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/forced_unwind.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/forced_unwind.cc
index 9059542..3c621d1 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/forced_unwind.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/forced_unwind.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target *-*-linux* *-*-gnu* } }
 // { dg-options "-pthread" { target *-*-linux* *-*-gnu* *-*-solaris* } }
 // { dg-require-effective-target c++11 }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/at_thread_exit.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/at_thread_exit.cc
index 72d1e66..5f0c7cd 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/at_thread_exit.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/at_thread_exit.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future.cc
index 85bbf5b..c7de321 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future2.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future2.cc
index 0ffd746..7b9d259 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future2.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/get_future2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke.cc
index fe4778a..5e09ef7 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke2.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke2.cc
index 27662d9..7790729 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke2.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke3.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke3.cc
index c3f5cec..411dd87 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke3.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke3.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke4.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke4.cc
index fb95c00..0fa2d09 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke4.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke4.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke5.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke5.cc
index 61fcb4a..fc7a33d 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke5.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/invoke5.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset.cc
index 1581b54..6aabe0d 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset2.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset2.cc
index 7581e36..dcdff24 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset2.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/reset2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/swap.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/swap.cc
index fa50b1d..466dfaa 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/swap.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/swap.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/members/valid.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/members/valid.cc
index 9b26152..1ee8c27 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/members/valid.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/members/valid.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/requirements/explicit_instantiation.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/requirements/explicit_instantiation.cc
index e3b61e4..05a8518 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/requirements/explicit_instantiation.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/requirements/explicit_instantiation.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/uses_allocator.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/uses_allocator.cc
index 1e2e9e0..fcee8c5 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/uses_allocator.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/uses_allocator.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/60966.cc b/libstdc++-v3/testsuite/30_threads/promise/60966.cc
index 4030ff8..238dae5 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/60966.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/60966.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/69106.cc b/libstdc++-v3/testsuite/30_threads/promise/69106.cc
index 322a2f4..7201a94 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/69106.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/69106.cc
@@ -18,7 +18,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 #include <future>
 
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/1.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/1.cc
index 2ca2a9e..54d1bda 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/1.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/1.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc.cc
index d23ee29..5012026 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc2.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc2.cc
index e7567af..eb51229 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc2.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc2.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc_min.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc_min.cc
index bdac11e..30d1be4 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/alloc_min.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/alloc_min.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
index 4cbef6d..caa59a5 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
index e66d047..f33673b 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/move.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/move.cc
index 5518840..93a97d1 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/move.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/move.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/move_assign.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/move_assign.cc
index 61ba488..2ec4c63 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/move_assign.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/move_assign.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/at_thread_exit.cc b/libstdc++-v3/testsuite/30_threads/promise/members/at_thread_exit.cc
index 5e8d9f3..3f1a40b 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/at_thread_exit.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/at_thread_exit.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2014-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/get_future.cc b/libstdc++-v3/testsuite/30_threads/promise/members/get_future.cc
index 209f545..0a2601d 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/get_future.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/get_future.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/get_future2.cc b/libstdc++-v3/testsuite/30_threads/promise/members/get_future2.cc
index 931da71..c5c14da 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/get_future2.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/get_future2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/set_exception.cc b/libstdc++-v3/testsuite/30_threads/promise/members/set_exception.cc
index 3672d18..cb3d003 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/set_exception.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/set_exception.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/set_exception2.cc b/libstdc++-v3/testsuite/30_threads/promise/members/set_exception2.cc
index e15d912..de725ef 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/set_exception2.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/set_exception2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/set_value.cc b/libstdc++-v3/testsuite/30_threads/promise/members/set_value.cc
index e3b7301..999ee31 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/set_value.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/set_value.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/set_value2.cc b/libstdc++-v3/testsuite/30_threads/promise/members/set_value2.cc
index bb26948..f63c847 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/set_value2.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/set_value2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/set_value3.cc b/libstdc++-v3/testsuite/30_threads/promise/members/set_value3.cc
index 1fa9d53..03c9aa2 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/set_value3.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/set_value3.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/members/swap.cc b/libstdc++-v3/testsuite/30_threads/promise/members/swap.cc
index b445d74..d718db9 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/members/swap.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/members/swap.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/requirements/explicit_instantiation.cc b/libstdc++-v3/testsuite/30_threads/promise/requirements/explicit_instantiation.cc
index 4a220a9..6b73bd9 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/requirements/explicit_instantiation.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/requirements/explicit_instantiation.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/promise/uses_allocator.cc b/libstdc++-v3/testsuite/30_threads/promise/uses_allocator.cc
index e19a891..9d10067 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/uses_allocator.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/uses_allocator.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign.cc
index 572c658..c8b0532 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/constexpr.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/constexpr.cc
index d0a5fe2..98b5098 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/constexpr.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/constexpr.cc
@@ -2,7 +2,6 @@ 
 // { dg-options "-fno-inline -g0" }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 // { dg-final { scan-assembler-not "_ZNSt13shared_futureIvEC2Ev" } }
 // { dg-final { scan-assembler-not "_ZNSt13shared_futureIiEC2Ev" } }
 
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/copy.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/copy.cc
index 4628858..40eed23 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/copy.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/copy.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/default.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/default.cc
index ba96ab3..567b2ec 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/default.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/default.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/move.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/move.cc
index 3d2666c..0484053 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/move.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/move.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/move_assign.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/move_assign.cc
index ae20b01..a6debee 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/move_assign.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/move_assign.cc
@@ -1,7 +1,6 @@ 
 // { dg-do run { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/45133.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/45133.cc
index 4548fcc..6b2bc3c 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/45133.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/45133.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/get.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/get.cc
index efb84df..f9447f6 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/get.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/get.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/get2.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/get2.cc
index 20db446..3a237d7 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/get2.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/get2.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/valid.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/valid.cc
index 747456c..5238821 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/valid.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/valid.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2010-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait.cc
index bf925f1..52058c8 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_for.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_for.cc
index 714c4d2..d38fe07 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_for.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_for.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_until.cc b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_until.cc
index e99979a..2f70874 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_until.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/members/wait_until.cc
@@ -3,7 +3,6 @@ 
 // { dg-require-effective-target c++11 }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/requirements/explicit_instantiation.cc b/libstdc++-v3/testsuite/30_threads/shared_future/requirements/explicit_instantiation.cc
index 715b7fe..49fc122 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/requirements/explicit_instantiation.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/requirements/explicit_instantiation.cc
@@ -1,7 +1,6 @@ 
 // { dg-do compile { target c++11 } }
 // { dg-require-cstdint "" }
 // { dg-require-gthreads "" }
-// { dg-require-atomic-builtins "" }
 
 // Copyright (C) 2009-2016 Free Software Foundation, Inc.
 //