[llvm] [Offload] Verify SyncCycle for events in AMDGPU (PR #149524)

[Ross Brunton via llvm-commits]

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@@ -1665,6 +1665,11 @@ Error AMDGPUStreamTy::waitEvent(const AMDGPUEventTy &Event) {
 Error AMDGPUStreamTy::synchronizeOn(AMDGPUEventTy &Event) {
   std::lock_guard<std::mutex> Lock(Mutex);
 
+  // If this event was for an older sync cycle, it has already been finalized
+  if (Event.RecordedSyncCycle < SyncCycle)
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RossBrunton wrote:

That, or if a later event gets consumed before an earlier one. If the latest event in the queue is synced on, the queue is reset and SyncCycle incremented.

https://github.com/llvm/llvm-project/pull/149524