Use recording queue if available for executable graph

Author: reble

sycl/source/detail/graph/graph_impl.cpp

@@ -549,6 +549,13 @@ graph_impl::add(std::shared_ptr<dynamic_command_group_impl> &DynCGImpl,
   return NodeImpl;
 }
 
+std::weak_ptr<sycl::detail::queue_impl> graph_impl::getQueue() const {
+  std::weak_ptr<sycl::detail::queue_impl> Return{};
+  if (!MRecordingQueues.empty())
+    Return = *(MRecordingQueues.begin());
+  return Return;
+}
+
 void graph_impl::addQueue(sycl::detail::queue_impl &RecordingQueue) {
   MRecordingQueues.insert(RecordingQueue.weak_from_this());
 }
@@ -870,7 +877,7 @@ void exec_graph_impl::createCommandBuffers(
 exec_graph_impl::exec_graph_impl(sycl::context Context,
                                  const std::shared_ptr<graph_impl> &GraphImpl,
                                  const property_list &PropList)
-    : MSchedule(), MGraphImpl(GraphImpl), MSyncPoints(), MQueueImpl(),
+    : MSchedule(), MGraphImpl(GraphImpl), MSyncPoints(),
       MDevice(GraphImpl->getDevice()), MContext(Context), MRequirements(),
       MSchedulerDependencies(),
       MIsUpdatable(PropList.has_property<property::graph::updatable>()),
@@ -890,6 +897,15 @@ exec_graph_impl::exec_graph_impl(sycl::context Context,
   }
   // Copy nodes from GraphImpl and merge any subgraph nodes into this graph.
   duplicateNodes();
+
+  if (auto PlaceholderQueuePtr = GraphImpl->getQueue().lock()) {
+    MQueueImpl = PlaceholderQueuePtr;
+  } else {
+    MQueueImpl = sycl::detail::queue_impl::create(
+        *sycl::detail::getSyclObjImpl(GraphImpl->getDevice()),
+        *sycl::detail::getSyclObjImpl(Context), sycl::async_handler{},
+        sycl::property_list{});
+  }
 }
 
 exec_graph_impl::~exec_graph_impl() {

sycl/source/detail/graph/graph_impl.hpp

@@ -172,6 +172,8 @@ class graph_impl : public std::enable_shared_from_this<graph_impl> {
   node_impl &add(std::shared_ptr<dynamic_command_group_impl> &DynCGImpl,
                  nodes_range Deps);
 
+  std::weak_ptr<sycl::detail::queue_impl> getQueue() const;
+
   /// Add a queue to the set of queues which are currently recording to this
   /// graph.
   /// @param RecordingQueue Queue to add to set.