Index: lib/CodeGen/MachineScheduler.cpp
===================================================================
--- lib/CodeGen/MachineScheduler.cpp
+++ lib/CodeGen/MachineScheduler.cpp
@@ -1962,16 +1962,18 @@
 
   if (SchedModel->hasInstrSchedModel() && SU->hasReservedResource) {
     const MCSchedClassDesc *SC = DAG->getSchedClass(SU);
-    for (TargetSchedModel::ProcResIter
-           PI = SchedModel->getWriteProcResBegin(SC),
-           PE = SchedModel->getWriteProcResEnd(SC); PI != PE; ++PI) {
-      unsigned NRCycle = getNextResourceCycle(PI->ProcResourceIdx, PI->Cycles);
+    for (const MCWriteProcResEntry &PE :
+          make_range(SchedModel->getWriteProcResBegin(SC),
+                     SchedModel->getWriteProcResEnd(SC))) {
+      unsigned ResIdx = PE.ProcResourceIdx;
+      unsigned Cycles = PE.Cycles;
+      unsigned NRCycle = getNextResourceCycle(ResIdx, Cycles);
       if (NRCycle > CurrCycle) {
 #ifndef NDEBUG
-        MaxObservedStall = std::max(PI->Cycles, MaxObservedStall);
+        MaxObservedStall = std::max(Cycles, MaxObservedStall);
 #endif
         DEBUG(dbgs() << "  SU(" << SU->NodeNum << ") "
-              << SchedModel->getResourceName(PI->ProcResourceIdx)
+              << SchedModel->getResourceName(ResIdx)
               << "=" << NRCycle << "c\n");
         return true;
       }