OpenCL: Tiny runtime optimizations

Plus remove an unused member variable.

Author: Henry Linjamäki

src/backend/OpenCL/CHIPBackendOpenCL.cc

@@ -1059,15 +1059,18 @@ void CL_CALLBACK pfn_notify(cl_event Event, cl_int CommandExecStatus,
 
 std::pair<std::vector<cl_event>, chipstar::LockGuardVector>
 CHIPQueueOpenCL::addDependenciesQueueSync(
-    std::shared_ptr<chipstar::Event> TargetEvent) {
+    std::shared_ptr<chipstar::Event> &TargetEvent) {
   auto [EventsToWaitOn, EventLocks] =
       getSyncQueuesLastEvents(TargetEvent, false);
   std::vector<cl_event> EventHandles;
-  EventHandles.reserve(EventsToWaitOn.size());
-  for (auto &Event : EventsToWaitOn) {
-    TargetEvent->addDependency(Event);
-    EventHandles.push_back(
-        std::static_pointer_cast<CHIPEventOpenCL>(Event)->ClEvent);
+
+  if (EventsToWaitOn.size()) {
+    EventHandles.reserve(EventsToWaitOn.size());
+    for (auto &Event : EventsToWaitOn) {
+      TargetEvent->addDependency(Event);
+      EventHandles.push_back(
+          std::static_pointer_cast<CHIPEventOpenCL>(Event)->ClEvent);
+    }
   }
   return {EventHandles, std::move(EventLocks)};
 }

src/backend/OpenCL/CHIPBackendOpenCL.hh

@@ -340,7 +340,7 @@ public:
   virtual std::shared_ptr<chipstar::Event>
   memPrefetchImpl(const void *Ptr, size_t Count) override;
   std::pair<std::vector<cl_event>, chipstar::LockGuardVector>
-  addDependenciesQueueSync(std::shared_ptr<chipstar::Event> TargetEvent);
+  addDependenciesQueueSync(std::shared_ptr<chipstar::Event> &TargetEvent);
 
 private:
   void switchModeTo(QueueMode Mode);
@@ -411,7 +411,6 @@ public:
       : ExecItem(GirdDim, BlockDim, SharedMem, ChipQueue) {}
 
   virtual ~CHIPExecItemOpenCL() override {}
-  SPVFuncInfo FuncInfo;
   virtual void setupAllArgs() override;
   cl_kernel getKernelHandle();