--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libatomic/host-config.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,86 @@
+/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
+   Contributed by Richard Henderson <rth@redhat.com>.
+
+   This file is part of the GNU Atomic Library (libatomic).
+
+   Libatomic 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 of the License, or
+   (at your option) any later version.
+
+   Libatomic 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/>.  */
+
+/* Included after all more target-specific host-config.h.  */
+
+
+/* The target may have some OS specific way to implement compare-and-swap.  */
+#if !defined(atomic_compare_exchange_n) && SIZE(HAVE_ATOMIC_CAS)
+# define atomic_compare_exchange_n  __atomic_compare_exchange_n
+#endif
+#if !defined(atomic_compare_exchange_w) && WSIZE(HAVE_ATOMIC_CAS)
+# define atomic_compare_exchange_w  __atomic_compare_exchange_n
+#endif
+
+/* For some targets, it may be significantly faster to avoid all barriers
+   if the user only wants relaxed memory order.  Sometimes we don't want
+   the extra code bloat.  In all cases, use the input to avoid warnings.  */
+#if defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
+# define maybe_specialcase_relaxed(x)	((x) == __ATOMIC_RELAXED)
+#else
+# define maybe_specialcase_relaxed(x)	((x) & 0)
+#endif
+
+/* Similar, but for targets for which the seq_cst model is sufficiently
+   more expensive than the acq_rel model.  */
+#if defined(WANT_SPECIALCASE_ACQREL) && !defined(__OPTIMIZE_SIZE__)
+# define maybe_specialcase_acqrel(x)	((x) != __ATOMIC_SEQ_CST)
+#else
+# define maybe_specialcase_acqrel(x)	((x) & 0)
+#endif
+
+
+/* The target may have some OS specific way to emit barriers.  */
+#ifndef pre_post_barrier
+static inline void __attribute__((always_inline, artificial))
+pre_barrier(int model)
+{
+  if (!maybe_specialcase_relaxed(model))
+    {
+      if (maybe_specialcase_acqrel(model))
+        __atomic_thread_fence (__ATOMIC_ACQ_REL);
+      else
+        __atomic_thread_fence (__ATOMIC_SEQ_CST);
+    }
+}
+static inline void __attribute__((always_inline, artificial))
+post_barrier(int model)
+{
+  pre_barrier(model);
+}
+#define pre_post_barrier 1
+#endif /* pre_post_barrier */
+
+/* Similar, but assume that acq_rel is already handled via locks.  */
+#ifndef pre_post_seq_barrier
+static inline void __attribute__((always_inline, artificial))
+pre_seq_barrier(int model)
+{
+}
+static inline void __attribute__((always_inline, artificial))
+post_seq_barrier(int model)
+{
+}
+#define pre_post_seq_barrier 1
+#endif