emit warning

Author: aidan.belton

sycl/plugins/cuda/pi_cuda.cpp

@@ -4803,12 +4803,14 @@ pi_result cuda_piextUSMEnqueueMemAdvise(pi_queue queue, const void *ptr,
   pi_result result = PI_SUCCESS;
   std::unique_ptr<_pi_event> event_ptr{nullptr};
 
-  // Ignore mem advice if memory is not managed
   unsigned int is_managed;
   PI_CHECK_ERROR(cuPointerGetAttribute(
       &is_managed, CU_POINTER_ATTRIBUTE_IS_MANAGED, (CUdeviceptr)ptr));
-  if (!is_managed)
-    return PI_SUCCESS;
+  if (!is_managed) {
+    setErrorMessage("Prefetch hint ignored as mem advise only works with USM",
+                    PI_SUCCESS);
+    return PI_PLUGIN_SPECIFIC_ERROR;
+  }
 
   try {
     ScopedContext active(queue->get_context());