[MiSched] - Simplify ProcResEntry access

[javed.absar]

Summary

Simplify the way ProcResource is iterated over.

[MatzeB]

LGTM.
Feel free to just push without review if you are just changing code to equivalent range-based for constructs like this in the future.

[javed.absar]

Thanks Matthias.

lib/CodeGen/MachineScheduler.cpp

if (CurrMOps > 0 &&
        (!isTop() && SchedModel->mustEndGroup(SU->getInstr())))) {
     DEBUG(dbgs() << "  hazard: SU(" << SU->NodeNum << ") must "
                  << (isTop()? "begin" : "end") << " group\n");
     return true;
   }
 
   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;
       }
     }
   }
   return false;
 }