(__sso_string_base<>::_M_assign): Likewise.
	* include/bits/atomic_2.h (_ITp<>::store): Use __sync_swap_full.
	(_ITp<>::store volatile): Same.
	(_PTp<>::store): Same.
	(_PTp<>::store volatile): Same.

Index: include/bits/atomic_2.h
===================================================================
--- include/bits/atomic_2.h	(revision 173831)
+++ include/bits/atomic_2.h	(working copy)
@@ -249,14 +249,12 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);
 	__glibcxx_assert(__m != memory_order_consume);
 
-	if (__m == memory_order_relaxed)
-	  _M_i = __i;
+	if (__m == memory_order_seq_cst)
+	  (void)__sync_swap_full (&_M_i, __i);
 	else
 	  {
 	    // write_mem_barrier();
 	    _M_i = __i;
-	    if (__m == memory_order_seq_cst)
-	      __sync_synchronize();
 	  }
       }
 
@@ -267,14 +265,12 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);
 	__glibcxx_assert(__m != memory_order_consume);
 
-	if (__m == memory_order_relaxed)
-	  _M_i = __i;
+	if (__m == memory_order_seq_cst)
+	  (void)__sync_swap_full (&_M_i, __i);
 	else
 	  {
 	    // write_mem_barrier();
 	    _M_i = __i;
-	    if (__m == memory_order_seq_cst)
-	      __sync_synchronize();
 	  }
       }
 
@@ -540,14 +536,12 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);
 	__glibcxx_assert(__m != memory_order_consume);
 
-	if (__m == memory_order_relaxed)
-	  _M_p = __p;
+	if (__m = memory_order_seq_cst)
+	  __sync_swap_full (&_M_p, __p);
 	else
 	  {
 	    // write_mem_barrier();
 	    _M_p = __p;
-	    if (__m == memory_order_seq_cst)
-	      __sync_synchronize();
 	  }
       }
 
@@ -559,14 +553,12 @@ namespace __atomic2
 	__glibcxx_assert(__m != memory_order_acq_rel);
 	__glibcxx_assert(__m != memory_order_consume);
 
-	if (__m == memory_order_relaxed)
-	  _M_p = __p;
+	if (__m = memory_order_seq_cst)
+	  __sync_swap_full (&_M_p, __p);
 	else
 	  {
 	    // write_mem_barrier();
 	    _M_p = __p;
-	    if (__m == memory_order_seq_cst)
-	      __sync_synchronize();
 	  }
       }