diff --git a/llvm/utils/TableGen/CodeGenSchedule.cpp b/llvm/utils/TableGen/CodeGenSchedule.cpp
index 50569b2..8a8911c 100644
--- a/llvm/utils/TableGen/CodeGenSchedule.cpp
+++ b/llvm/utils/TableGen/CodeGenSchedule.cpp
@@ -162,8 +162,8 @@
 
   // For each processor, find a unique machine model.
   DEBUG(dbgs() << "+++ PROCESSOR MODELs (addProcModel) +++\n");
-  for (unsigned i = 0, N = ProcRecords.size(); i < N; ++i)
-    addProcModel(ProcRecords[i]);
+  for (Record *ProcRecord : ProcRecords)
+    addProcModel(ProcRecord);
 }
 
 /// Get a unique processor model based on the defined MachineModel and
@@ -194,20 +194,20 @@
   if (!RWSet.insert(RWDef).second)
     return;
   RWDefs.push_back(RWDef);
-  // Reads don't current have sequence records, but it can be added later.
+  // Reads don't currently have sequence records, but it can be added later.
   if (RWDef->isSubClassOf("WriteSequence")) {
     RecVec Seq = RWDef->getValueAsListOfDefs("Writes");
-    for (RecIter I = Seq.begin(), E = Seq.end(); I != E; ++I)
-      scanSchedRW(*I, RWDefs, RWSet);
+    for (Record *WSRec : Seq)
+      scanSchedRW(WSRec, RWDefs, RWSet);
   }
   else if (RWDef->isSubClassOf("SchedVariant")) {
     // Visit each variant (guarded by a different predicate).
     RecVec Vars = RWDef->getValueAsListOfDefs("Variants");
-    for (RecIter VI = Vars.begin(), VE = Vars.end(); VI != VE; ++VI) {
+    for (Record *Variant : Vars) {
       // Visit each RW in the sequence selected by the current variant.
-      RecVec Selected = (*VI)->getValueAsListOfDefs("Selected");
-      for (RecIter I = Selected.begin(), E = Selected.end(); I != E; ++I)
-        scanSchedRW(*I, RWDefs, RWSet);
+      RecVec Selected = Variant->getValueAsListOfDefs("Selected");
+      for (Record *SelDef : Selected)
+        scanSchedRW(SelDef, RWDefs, RWSet);
     }
   }
 }
@@ -228,42 +228,40 @@
     if (SchedDef->isValueUnset("SchedRW"))
       continue;
     RecVec RWs = SchedDef->getValueAsListOfDefs("SchedRW");
-    for (RecIter RWI = RWs.begin(), RWE = RWs.end(); RWI != RWE; ++RWI) {
-      if ((*RWI)->isSubClassOf("SchedWrite"))
-        scanSchedRW(*RWI, SWDefs, RWSet);
+    for (Record *RW : RWs) {
+      if (RW->isSubClassOf("SchedWrite"))
+        scanSchedRW(RW, SWDefs, RWSet);
       else {
-        assert((*RWI)->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
-        scanSchedRW(*RWI, SRDefs, RWSet);
+        assert(RW->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
+        scanSchedRW(RW, SRDefs, RWSet);
       }
     }
   }
   // Find all ReadWrites referenced by InstRW.
   RecVec InstRWDefs = Records.getAllDerivedDefinitions("InstRW");
-  for (RecIter OI = InstRWDefs.begin(), OE = InstRWDefs.end(); OI != OE; ++OI) {
+  for (Record *InstRWDef : InstRWDefs) {
     // For all OperandReadWrites.
-    RecVec RWDefs = (*OI)->getValueAsListOfDefs("OperandReadWrites");
-    for (RecIter RWI = RWDefs.begin(), RWE = RWDefs.end();
-         RWI != RWE; ++RWI) {
-      if ((*RWI)->isSubClassOf("SchedWrite"))
-        scanSchedRW(*RWI, SWDefs, RWSet);
+    RecVec RWDefs = InstRWDef->getValueAsListOfDefs("OperandReadWrites");
+    for (Record *RWDef : RWDefs) {
+      if (RWDef->isSubClassOf("SchedWrite"))
+        scanSchedRW(RWDef, SWDefs, RWSet);
       else {
-        assert((*RWI)->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
-        scanSchedRW(*RWI, SRDefs, RWSet);
+        assert(RWDef->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
+        scanSchedRW(RWDef, SRDefs, RWSet);
       }
     }
   }
   // Find all ReadWrites referenced by ItinRW.
   RecVec ItinRWDefs = Records.getAllDerivedDefinitions("ItinRW");
-  for (RecIter II = ItinRWDefs.begin(), IE = ItinRWDefs.end(); II != IE; ++II) {
+  for (Record *ItinRWDef : ItinRWDefs) {
     // For all OperandReadWrites.
-    RecVec RWDefs = (*II)->getValueAsListOfDefs("OperandReadWrites");
-    for (RecIter RWI = RWDefs.begin(), RWE = RWDefs.end();
-         RWI != RWE; ++RWI) {
-      if ((*RWI)->isSubClassOf("SchedWrite"))
-        scanSchedRW(*RWI, SWDefs, RWSet);
+    RecVec RWDefs = ItinRWDef->getValueAsListOfDefs("OperandReadWrites");
+    for (Record *RWDef : RWDefs) {
+      if (RWDef->isSubClassOf("SchedWrite"))
+        scanSchedRW(RWDef, SWDefs, RWSet);
       else {
-        assert((*RWI)->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
-        scanSchedRW(*RWI, SRDefs, RWSet);
+        assert(RWDef->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
+        scanSchedRW(RWDef, SRDefs, RWSet);
       }
     }
   }
@@ -271,50 +269,49 @@
   // for the loop below that initializes Alias vectors.
   RecVec AliasDefs = Records.getAllDerivedDefinitions("SchedAlias");
   std::sort(AliasDefs.begin(), AliasDefs.end(), LessRecord());
-  for (RecIter AI = AliasDefs.begin(), AE = AliasDefs.end(); AI != AE; ++AI) {
-    Record *MatchDef = (*AI)->getValueAsDef("MatchRW");
-    Record *AliasDef = (*AI)->getValueAsDef("AliasRW");
+  for (Record *ADef : AliasDefs) {
+    Record *MatchDef = ADef->getValueAsDef("MatchRW");
+    Record *AliasDef = ADef->getValueAsDef("AliasRW");
     if (MatchDef->isSubClassOf("SchedWrite")) {
       if (!AliasDef->isSubClassOf("SchedWrite"))
-        PrintFatalError((*AI)->getLoc(), "SchedWrite Alias must be SchedWrite");
+        PrintFatalError(ADef->getLoc(), "SchedWrite Alias must be SchedWrite");
       scanSchedRW(AliasDef, SWDefs, RWSet);
     }
     else {
       assert(MatchDef->isSubClassOf("SchedRead") && "Unknown SchedReadWrite");
       if (!AliasDef->isSubClassOf("SchedRead"))
-        PrintFatalError((*AI)->getLoc(), "SchedRead Alias must be SchedRead");
+        PrintFatalError(ADef->getLoc(), "SchedRead Alias must be SchedRead");
       scanSchedRW(AliasDef, SRDefs, RWSet);
     }
   }
   // Sort and add the SchedReadWrites directly referenced by instructions or
   // itinerary resources. Index reads and writes in separate domains.
   std::sort(SWDefs.begin(), SWDefs.end(), LessRecord());
-  for (RecIter SWI = SWDefs.begin(), SWE = SWDefs.end(); SWI != SWE; ++SWI) {
-    assert(!getSchedRWIdx(*SWI, /*IsRead=*/false) && "duplicate SchedWrite");
-    SchedWrites.emplace_back(SchedWrites.size(), *SWI);
+  for (Record *SWDef : SWDefs) {
+    assert(!getSchedRWIdx(SWDef, /*IsRead=*/false) && "duplicate SchedWrite");
+    SchedWrites.emplace_back(SchedWrites.size(), SWDef);
   }
   std::sort(SRDefs.begin(), SRDefs.end(), LessRecord());
-  for (RecIter SRI = SRDefs.begin(), SRE = SRDefs.end(); SRI != SRE; ++SRI) {
-    assert(!getSchedRWIdx(*SRI, /*IsRead-*/true) && "duplicate SchedWrite");
-    SchedReads.emplace_back(SchedReads.size(), *SRI);
+  for (Record *SRDef : SRDefs) {
+    assert(!getSchedRWIdx(SRDef, /*IsRead-*/true) && "duplicate SchedWrite");
+    SchedReads.emplace_back(SchedReads.size(), SRDef);
   }
   // Initialize WriteSequence vectors.
-  for (std::vector<CodeGenSchedRW>::iterator WI = SchedWrites.begin(),
-         WE = SchedWrites.end(); WI != WE; ++WI) {
-    if (!WI->IsSequence)
+  for (CodeGenSchedRW &CGRW : SchedWrites) {
+    if (!CGRW.IsSequence)
       continue;
-    findRWs(WI->TheDef->getValueAsListOfDefs("Writes"), WI->Sequence,
+    findRWs(CGRW.TheDef->getValueAsListOfDefs("Writes"), CGRW.Sequence,
             /*IsRead=*/false);
   }
   // Initialize Aliases vectors.
-  for (RecIter AI = AliasDefs.begin(), AE = AliasDefs.end(); AI != AE; ++AI) {
-    Record *AliasDef = (*AI)->getValueAsDef("AliasRW");
+  for (Record *ADef : AliasDefs) {
+    Record *AliasDef = ADef->getValueAsDef("AliasRW");
     getSchedRW(AliasDef).IsAlias = true;
-    Record *MatchDef = (*AI)->getValueAsDef("MatchRW");
+    Record *MatchDef = ADef->getValueAsDef("MatchRW");
     CodeGenSchedRW &RW = getSchedRW(MatchDef);
     if (RW.IsAlias)
-      PrintFatalError((*AI)->getLoc(), "Cannot Alias an Alias");
-    RW.Aliases.push_back(*AI);
+      PrintFatalError(ADef->getLoc(), "Cannot Alias an Alias");
+    RW.Aliases.push_back(ADef);
   }
   DEBUG(
     dbgs() << "\n+++ SCHED READS and WRITES (collectSchedRW) +++\n";
@@ -329,12 +326,11 @@
       dbgs() << '\n';
     }
     RecVec RWDefs = Records.getAllDerivedDefinitions("SchedReadWrite");
-    for (RecIter RI = RWDefs.begin(), RE = RWDefs.end();
-         RI != RE; ++RI) {
-      if (!getSchedRWIdx(*RI, (*RI)->isSubClassOf("SchedRead"))) {
-        const std::string &Name = (*RI)->getName();
+    for (Record *RWDef : RWDefs) {
+      if (!getSchedRWIdx(RWDef, RWDef->isSubClassOf("SchedRead"))) {
+        const std::string &Name = RWDef->getName();
         if (Name != "NoWrite" && Name != "ReadDefault")
-          dbgs() << "Unused SchedReadWrite " << (*RI)->getName() << '\n';
+          dbgs() << "Unused SchedReadWrite " << RWDef->getName() << '\n';
       }
     });
 }
@@ -364,8 +360,8 @@
 }
 
 bool CodeGenSchedModels::hasReadOfWrite(Record *WriteDef) const {
-  for (unsigned i = 0, e = SchedReads.size(); i < e; ++i) {
-    Record *ReadDef = SchedReads[i].TheDef;
+  for (const CodeGenSchedRW &Read : SchedReads) {
+    Record *ReadDef = Read.TheDef;
     if (!ReadDef || !ReadDef->isSubClassOf("ProcReadAdvance"))
       continue;
 
@@ -381,12 +377,12 @@
 
 void splitSchedReadWrites(const RecVec &RWDefs,
                           RecVec &WriteDefs, RecVec &ReadDefs) {
-  for (RecIter RWI = RWDefs.begin(), RWE = RWDefs.end(); RWI != RWE; ++RWI) {
-    if ((*RWI)->isSubClassOf("SchedWrite"))
-      WriteDefs.push_back(*RWI);
+  for (Record *RWDef : RWDefs) {
+    if (RWDef->isSubClassOf("SchedWrite"))
+      WriteDefs.push_back(RWDef);
     else {
-      assert((*RWI)->isSubClassOf("SchedRead") && "unknown SchedReadWrite");
-      ReadDefs.push_back(*RWI);
+      assert(RWDef->isSubClassOf("SchedRead") && "unknown SchedReadWrite");
+      ReadDefs.push_back(RWDef);
     }
   }
 }
@@ -406,8 +402,8 @@
 // Call getSchedRWIdx for all elements in a sequence of SchedRW defs.
 void CodeGenSchedModels::findRWs(const RecVec &RWDefs, IdxVec &RWs,
                                  bool IsRead) const {
-  for (RecIter RI = RWDefs.begin(), RE = RWDefs.end(); RI != RE; ++RI) {
-    unsigned Idx = getSchedRWIdx(*RI, IsRead);
+  for (Record *RWDef : RWDefs) {
+    unsigned Idx = getSchedRWIdx(RWDef, IsRead);
     assert(Idx && "failed to collect SchedReadWrite");
     RWs.push_back(Idx);
   }
@@ -423,9 +419,8 @@
   int Repeat =
     SchedRW.TheDef ? SchedRW.TheDef->getValueAsInt("Repeat") : 1;
   for (int i = 0; i < Repeat; ++i) {
-    for (IdxIter I = SchedRW.Sequence.begin(), E = SchedRW.Sequence.end();
-         I != E; ++I) {
-      expandRWSequence(*I, RWSeq, IsRead);
+    for (unsigned I : SchedRW.Sequence) {
+      expandRWSequence(I, RWSeq, IsRead);
     }
   }
 }
@@ -464,9 +459,8 @@
   int Repeat =
     SchedWrite.TheDef ? SchedWrite.TheDef->getValueAsInt("Repeat") : 1;
   for (int i = 0; i < Repeat; ++i) {
-    for (IdxIter I = SchedWrite.Sequence.begin(), E = SchedWrite.Sequence.end();
-         I != E; ++I) {
-      expandRWSeqForProc(*I, RWSeq, IsRead, ProcModel);
+    for (unsigned I : SchedWrite.Sequence) {
+      expandRWSeqForProc(I, RWSeq, IsRead, ProcModel);
     }
   }
 }
@@ -535,8 +529,8 @@
   RecVec InstRWDefs = Records.getAllDerivedDefinitions("InstRW");
   std::sort(InstRWDefs.begin(), InstRWDefs.end(), LessRecord());
   DEBUG(dbgs() << "\n+++ SCHED CLASSES (createInstRWClass) +++\n");
-  for (RecIter OI = InstRWDefs.begin(), OE = InstRWDefs.end(); OI != OE; ++OI)
-    createInstRWClass(*OI);
+  for (Record *RWDef : InstRWDefs)
+    createInstRWClass(RWDef);
 
   NumInstrSchedClasses = SchedClasses.size();
 
@@ -575,20 +569,19 @@
       dbgs() << '\n';
     }
     const RecVec &RWDefs = SchedClasses[SCIdx].InstRWs;
-    for (RecIter RWI = RWDefs.begin(), RWE = RWDefs.end();
-         RWI != RWE; ++RWI) {
+    for (Record *RWDef : RWDefs) {
       const CodeGenProcModel &ProcModel =
-        getProcModel((*RWI)->getValueAsDef("SchedModel"));
+        getProcModel(RWDef->getValueAsDef("SchedModel"));
       ProcIndices.push_back(ProcModel.Index);
       dbgs() << "InstRW on " << ProcModel.ModelName << " for " << InstName;
       IdxVec Writes;
       IdxVec Reads;
-      findRWs((*RWI)->getValueAsListOfDefs("OperandReadWrites"),
+      findRWs(RWDef->getValueAsListOfDefs("OperandReadWrites"),
               Writes, Reads);
-      for (IdxIter WI = Writes.begin(), WE = Writes.end(); WI != WE; ++WI)
-        dbgs() << " " << SchedWrites[*WI].Name;
-      for (IdxIter RI = Reads.begin(), RE = Reads.end(); RI != RE; ++RI)
-        dbgs() << " " << SchedReads[*RI].Name;
+      for (unsigned WIdx : Writes)
+        dbgs() << " " << SchedWrites[WIdx].Name;
+      for (unsigned RIdx : Reads)
+        dbgs() << " " << SchedReads[RIdx].Name;
       dbgs() << '\n';
     }
     // If ProcIndices contains zero, the class applies to all processors.
@@ -729,9 +722,8 @@
       if (!RWDefs.empty()) {
         const RecVec *OrigInstDefs = Sets.expand(RWDefs[0]);
         unsigned OrigNumInstrs = 0;
-        for (RecIter I = OrigInstDefs->begin(), E = OrigInstDefs->end();
-             I != E; ++I) {
-          if (InstrClassMap[*I] == OldSCIdx)
+        for (Record *OIDef : make_range(OrigInstDefs->begin(), OrigInstDefs->end())) {
+          if (InstrClassMap[OIDef] == OldSCIdx)
             ++OrigNumInstrs;
         }
         if (OrigNumInstrs == InstDefs.size()) {
@@ -785,9 +777,8 @@
 
 // True if collectProcItins found anything.
 bool CodeGenSchedModels::hasItineraries() const {
-  for (CodeGenSchedModels::ProcIter PI = procModelBegin(), PE = procModelEnd();
-       PI != PE; ++PI) {
-    if (PI->hasItineraries())
+  for (const CodeGenProcModel &PM : make_range(procModelBegin(),procModelEnd())) {
+    if (PM.hasItineraries())
       return true;
   }
   return false;
@@ -1695,30 +1686,26 @@
   assert(!ProcResourceDefs.empty());
   assert(!ProcResGroups.empty());
 
-  for (RecIter RI = ProcResourceDefs.begin(), RE = ProcResourceDefs.end();
-       RI != RE; ++RI) {
-
-    if ((*RI)->getValueAsDef("Kind") == ProcResKind
-        && (*RI)->getValueAsDef("SchedModel") == PM.ModelDef) {
+  for (Record *ProcResDef : ProcResourceDefs) {
+    if (ProcResDef->getValueAsDef("Kind") == ProcResKind
+        && ProcResDef->getValueAsDef("SchedModel") == PM.ModelDef) {
       if (ProcUnitDef) {
-        PrintFatalError((*RI)->getLoc(),
+        PrintFatalError(ProcResDef->getLoc(),
                         "Multiple ProcessorResourceUnits associated with "
                         + ProcResKind->getName());
       }
-      ProcUnitDef = *RI;
+      ProcUnitDef = ProcResDef;
     }
   }
-  for (RecIter RI = ProcResGroups.begin(), RE = ProcResGroups.end();
-       RI != RE; ++RI) {
-
-    if (*RI == ProcResKind
-        && (*RI)->getValueAsDef("SchedModel") == PM.ModelDef) {
+  for (Record *ProcResGroup : ProcResGroups) {
+    if (ProcResGroup == ProcResKind
+        && ProcResGroup->getValueAsDef("SchedModel") == PM.ModelDef) {
       if (ProcUnitDef) {
-        PrintFatalError((*RI)->getLoc(),
+        PrintFatalError((ProcResGroup)->getLoc(),
                         "Multiple ProcessorResourceUnits associated with "
                         + ProcResKind->getName());
       }
-      ProcUnitDef = *RI;
+      ProcUnitDef = ProcResGroup;
     }
   }
   if (!ProcUnitDef) {
@@ -1832,9 +1819,8 @@
   dbgs() << "\n  ProcIdx: "; dumpIdxVec(ProcIndices); dbgs() << '\n';
   if (!Transitions.empty()) {
     dbgs() << "\n Transitions for Proc ";
-    for (std::vector<CodeGenSchedTransition>::const_iterator
-           TI = Transitions.begin(), TE = Transitions.end(); TI != TE; ++TI) {
-      dumpIdxVec(TI->ProcIndices);
+    for (const CodeGenSchedTransition &Transition : Transitions) {
+      dumpIdxVec(Transition.ProcIndices);
     }
   }
 }