[SYCL] Ignore usm prefetch dummy flag (#4568)

Patch removes assertions in pi_cuda, pi_hip, and pi_level_zero which fail based upon the flag given to the function.
`prefetch_usm` function now does not pass flag to PI.
The flag is a placeholder and should be ignored.

This is a follow up PR from issue #4467

Author: AidanBeltonS

sycl/include/CL/sycl/detail/pi.h

@@ -1560,6 +1560,9 @@ typedef enum : pi_bitfield {
   PI_MEM_ALLOC_FLAGS = CL_MEM_ALLOC_FLAGS_INTEL
 } _pi_usm_mem_properties;
 
+// Flag is used for piProgramUSMEnqueuePrefetch. PI_USM_MIGRATION_TBD0 is a
+// placeholder for future developments and should not change the behaviour of
+// piProgramUSMEnqueuePrefetch
 typedef enum : pi_bitfield {
   PI_USM_MIGRATION_TBD0 = (1 << 0)
 } _pi_usm_migration_flags;

sycl/plugins/cuda/pi_cuda.cpp

@@ -4610,16 +4610,16 @@ pi_result cuda_piextUSMEnqueuePrefetch(pi_queue queue, const void *ptr,
                                        pi_uint32 num_events_in_waitlist,
                                        const pi_event *events_waitlist,
                                        pi_event *event) {
+
+  // flags is currently unused so fail if set
+  if (flags != 0)
+    return PI_INVALID_VALUE;
   assert(queue != nullptr);
   assert(ptr != nullptr);
   CUstream cuStream = queue->get();
   pi_result result = PI_SUCCESS;
   std::unique_ptr<_pi_event> event_ptr{nullptr};
 
-  // TODO implement handling the flags once the expected behaviour
-  // of piextUSMEnqueuePrefetch is detailed in the USM extension
-  assert(flags == 0u);
-
   try {
     ScopedContext active(queue->get_context());
     result = cuda_piEnqueueEventsWait(queue, num_events_in_waitlist,

sycl/plugins/hip/pi_hip.cpp

@@ -4445,16 +4445,15 @@ pi_result hip_piextUSMEnqueuePrefetch(pi_queue queue, const void *ptr,
                                       const pi_event *events_waitlist,
                                       pi_event *event) {
 
+  // flags is currently unused so fail if set
+  if (flags != 0)
+    return PI_INVALID_VALUE;
   assert(queue != nullptr);
   assert(ptr != nullptr);
   hipStream_t hipStream = queue->get();
   pi_result result = PI_SUCCESS;
   std::unique_ptr<_pi_event> event_ptr{nullptr};
 
-  // TODO implement handling the flags once the expected behaviour
-  // of piextUSMEnqueuePrefetch is detailed in the USM extension
-  assert(flags == 0u);
-
   try {
     ScopedContext active(queue->get_context());
     result = hip_piEnqueueEventsWait(queue, num_events_in_waitlist,

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -6648,7 +6648,9 @@ pi_result piextUSMEnqueuePrefetch(pi_queue Queue, const void *Ptr, size_t Size,
                                   pi_uint32 NumEventsInWaitList,
                                   const pi_event *EventWaitList,
                                   pi_event *Event) {
-  PI_ASSERT(!(Flags & ~PI_USM_MIGRATION_TBD0), PI_INVALID_VALUE);
+
+  // flags is currently unused so fail if set
+  PI_ASSERT(Flags == 0, PI_INVALID_VALUE);
   PI_ASSERT(Queue, PI_INVALID_QUEUE);
   PI_ASSERT(Event, PI_INVALID_EVENT);
 

sycl/plugins/opencl/pi_opencl.cpp

@@ -1012,7 +1012,10 @@ pi_result piextUSMEnqueuePrefetch(pi_queue queue, const void *ptr, size_t size,
                                   pi_event *event) {
   (void)ptr;
   (void)size;
-  (void)flags;
+
+  // flags is currently unused so fail if set
+  if (flags != 0)
+    return PI_INVALID_VALUE;
 
   return cast<pi_result>(clEnqueueMarkerWithWaitList(
       cast<cl_command_queue>(queue), num_events_in_waitlist,

sycl/source/detail/memory_manager.cpp

@@ -698,7 +698,7 @@ void MemoryManager::prefetch_usm(void *Mem, QueueImplPtr Queue, size_t Length,
   } else {
     const detail::plugin &Plugin = Queue->getPlugin();
     Plugin.call<PiApiKind::piextUSMEnqueuePrefetch>(
-        Queue->getHandleRef(), Mem, Length, PI_USM_MIGRATION_TBD0,
+        Queue->getHandleRef(), Mem, Length, _pi_usm_migration_flags(0),
         DepEvents.size(), DepEvents.data(), &OutEvent);
   }
 }