TPCClusterFinder: Fix how to determine if a sector is empty.

Author: fweig

GPU/GPUTracking/Global/GPUChainTrackingClusterizer.cxx

@@ -622,6 +622,7 @@ int GPUChainTracking::RunTPCClusterizer(bool synchronizeOutput)
       SynchronizeStream(lane);
       GPUTPCClusterFinder& clusterer = processors()->tpcClusterer[iSlice];
       GPUTPCClusterFinder& clustererShadow = doGPU ? processorsShadow()->tpcClusterer[iSlice] : clusterer;
+
       if (laneHasData[lane]) {
         anyLaneHasData = true;
         if (buildNativeGPU && GetProcessingSettings().tpccfGatherKernel) {
@@ -645,14 +646,16 @@ int GPUChainTracking::RunTPCClusterizer(bool synchronizeOutput)
         transferRunning[lane] = 1;
       }
 
-      if (not propagateMCLabels || clusterer.mPmemory->counters.nClusters == 0) {
+      if (not propagateMCLabels || not laneHasData[lane]) {
+        assert(propagateMCLabels ? mcLinearLabels.header.size() == nClsTotal : true);
         continue;
       }
 
       runKernel<GPUTPCCFMCLabelFlattener, GPUTPCCFMCLabelFlattener::setRowOffsets>(GetGrid(GPUCA_ROW_COUNT, lane, GPUReconstruction::krnlDeviceType::CPU), {iSlice}, {});
       GPUTPCCFMCLabelFlattener::setGlobalOffsetsAndAllocate(clusterer, mcLinearLabels);
       runKernel<GPUTPCCFMCLabelFlattener, GPUTPCCFMCLabelFlattener::flatten>(GetGrid(GPUCA_ROW_COUNT, lane, GPUReconstruction::krnlDeviceType::CPU), {iSlice}, {}, &mcLinearLabels);
       clusterer.clearMCMemory();
+      assert(propagateMCLabels ? mcLinearLabels.header.size() == nClsTotal : true);
     }
     if (buildNativeHost && buildNativeGPU && anyLaneHasData) {
       if (GetProcessingSettings().delayedOutput) {