--- a/include/qthread/qthread.hpp
+++ b/include/qthread/qthread.hpp
@@ -236,7 +236,7 @@
             return qthread_incr64((uint64_t *)operand, incr);
 
         default:
-            *(int *)(0) = 0;
+            __builtin_trap();
     }
     return T(0);                       // never hit - keep compiler happy
 }
