diff --git a/lib/io.h b/lib/io.h
index ba416dd5..8cd03e41 100644
--- a/lib/io.h
+++ b/lib/io.h
@@ -30,8 +30,9 @@ extern "C" {
  *  @{
  */
 
-#ifdef __MICROBLAZE__
-#define NO_ATOMIC_64_SUPPORT
+#if defined(__MICROBLAZE__) || \
+   (defined(__GNUC__) && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8))
+#  define NO_ATOMIC_64_SUPPORT
 #endif
 
 struct metal_io_region;