--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libatomic/gload.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,100 @@
+/* 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/>.  */
+
+#include "libatomic_i.h"
+
+
+/* If we natively support the load, and if we're unconcerned with extra
+   barriers (e.g. fully in-order cpu for which barriers are a nop), then
+   go ahead and expand the operation inline.  */
+#if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
+# define EXACT_INLINE(N, DEST, SRC, DONE)			\
+  if (C2(HAVE_ATOMIC_LDST_,N))					\
+    {								\
+      DEST = __atomic_load_n (SRC, __ATOMIC_SEQ_CST);		\
+      DONE;							\
+    }
+#else
+# define EXACT_INLINE(N, DEST, SRC, DONE)
+#endif
+
+
+#define EXACT_(N, DEST, SRC, DONE)				\
+  do {								\
+    EXACT_INLINE (N, DEST, SRC, DONE);				\
+    DEST = C3(local_,load_,N) (SRC, smodel);			\
+    DONE;							\
+  } while (0)
+
+#define EXACT(N)						\
+  do {								\
+    if (!C2(HAVE_INT,N)) break;					\
+    if ((uintptr_t)mptr & (N - 1)) break;			\
+    EXACT_(N, *PTR(N,rptr), PTR(N,mptr), return);		\
+  } while (0)
+
+#define LARGER(N)						\
+  do {								\
+    if (!C2(HAVE_INT,N)) break;					\
+    r = (uintptr_t)mptr & (N - 1);				\
+    a = (uintptr_t)mptr & -N;					\
+    if (r + n <= N)						\
+      EXACT_ (N, u.C2(i,N), PTR(N,a), goto Lfinish);		\
+  } while (0)
+
+
+void
+libat_load (size_t n, void *mptr, void *rptr, int smodel)
+{
+  union max_size_u u;
+  uintptr_t r, a;
+
+  switch (n)
+    {
+    case 0:				return;
+    case 1:		EXACT(1);	goto L4;
+    case 2:		EXACT(2);	goto L4;
+    case 4:		EXACT(4);	goto L8;
+    case 8:		EXACT(8);	goto L16;
+    case 16:		EXACT(16);	break;
+
+    case 3: L4:		LARGER(4);	/* FALLTHRU */
+    case 5 ... 7: L8:	LARGER(8);	/* FALLTHRU */
+    case 9 ... 15: L16:	LARGER(16);	break;
+
+    Lfinish:
+      memcpy (rptr, u.b + r, n);
+      return;
+    }
+
+  pre_seq_barrier (smodel);
+  libat_lock_n (mptr, n);
+
+  memcpy (rptr, mptr, n);
+
+  libat_unlock_n (mptr, n);
+  post_seq_barrier (smodel);
+}
+
+EXPORT_ALIAS (load);