arm: Install __sync libfuncs for Linux.

        * config/arm/arm.c (arm_init_libfuncs): Call init_sync_libfuncs
        for Linux.

From-SVN: r181755

gcc/ChangeLog

 2011-11-26  Richard Henderson  <rth@redhat.com>
 
+	* config/arm/arm.c (arm_init_libfuncs): Call init_sync_libfuncs
+	for Linux.
+
+2011-11-26  Richard Henderson  <rth@redhat.com>
+
 	* optabs.c (expand_atomic_fetch_op): Always return result.
 
 	* optabs.c (init_sync_libfuncs_1): Include max in iteration.

gcc/config/arm/arm.c

@@ -1096,6 +1096,10 @@ arm_set_fixed_conv_libfunc (convert_optab optable, enum machine_mode to,
 static void
 arm_init_libfuncs (void)
 {
+  /* For Linux, we have access to kernel support for atomic operations.  */
+  if (arm_abi == ARM_ABI_AAPCS_LINUX)
+    init_sync_libfuncs (2 * UNITS_PER_WORD);
+
   /* There are no special library functions unless we are using the
      ARM BPABI.  */
   if (!TARGET_BPABI)