--- old/src/os_cpu/linux_aarch64/vm/atomic_linux_aarch64.hpp	2017-08-16 01:47:22.333097139 -0400
+++ new/src/os_cpu/linux_aarch64/vm/atomic_linux_aarch64.hpp	2017-08-16 01:47:22.221091386 -0400
@@ -91,6 +91,7 @@
                                                         T volatile* dest,
                                                         T compare_value,
                                                         cmpxchg_memory_order) const {
+  STATIC_ASSERT(byte_size == sizeof(T));
   if (order == memory_order_relaxed) {
     T value = compare_value;
     __atomic_compare_exchange(dest, &value, &exchange_value, /*weak*/false,