diff --git a/qemu/include/qemu/atomic.h b/qemu/include/qemu/atomic.h
index 4f360050..17f38ba9 100644
--- a/qemu/include/qemu/atomic.h
+++ b/qemu/include/qemu/atomic.h
@@ -42,7 +42,17 @@ void _ReadWriteBarrier(void);
 #define smp_wmb()   ({ barrier(); __atomic_thread_fence(__ATOMIC_RELEASE); barrier(); })
 #define smp_rmb()   ({ barrier(); __atomic_thread_fence(__ATOMIC_ACQUIRE); barrier(); })
 
+/* Most compilers currently treat consume and acquire the same, but really
+ * no processors except Alpha need a barrier here.  Leave it in if
+ * using Thread Sanitizer to avoid warnings, otherwise optimize it away.
+ */
+#if defined(__SANITIZE_THREAD__)
 #define smp_read_barrier_depends() ({ barrier(); __atomic_thread_fence(__ATOMIC_CONSUME); barrier(); })
+#elsif defined(__alpha__)
+#define smp_read_barrier_depends()   asm volatile("mb":::"memory")
+#else
+#define smp_read_barrier_depends()   barrier()
+#endif
 
 /* Weak atomic operations prevent the compiler moving other
  * loads/stores past the atomic operation load/store. However there is