diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index 7998a1ae5c6ed..d34634111ecf0 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -446,9 +446,8 @@ doPromotion(Function *F, SmallPtrSetImpl<Argument *> &ArgsToPromote,
                "GEPs without uses should be cleaned up already");
         IndicesVector Operands;
         Operands.reserve(GEP->getNumIndices());
-        for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end();
-             II != IE; ++II)
-          Operands.push_back(cast<ConstantInt>(*II)->getSExtValue());
+        for (const Use &Idx : GEP->indices())
+          Operands.push_back(cast<ConstantInt>(Idx)->getSExtValue());
 
         // GEPs with a single 0 index can be merged with direct loads
         if (Operands.size() == 1 && Operands.front() == 0)
@@ -634,9 +633,8 @@ static bool isSafeToPromoteArgument(Argument *Arg, Type *ByValTy, AAResults &AAR
         if (V == Arg) {
           // This load actually loads (part of) Arg? Check the indices then.
           Indices.reserve(GEP->getNumIndices());
-          for (User::op_iterator II = GEP->idx_begin(), IE = GEP->idx_end();
-               II != IE; ++II)
-            if (ConstantInt *CI = dyn_cast<ConstantInt>(*II))
+          for (Use &Idx : GEP->indices())
+            if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx))
               Indices.push_back(CI->getSExtValue());
             else
               // We found a non-constant GEP index for this argument? Bail out
@@ -689,9 +687,8 @@ static bool isSafeToPromoteArgument(Argument *Arg, Type *ByValTy, AAResults &AAR
         return false;
 
       // Ensure that all of the indices are constants.
-      for (User::op_iterator i = GEP->idx_begin(), e = GEP->idx_end(); i != e;
-           ++i)
-        if (ConstantInt *C = dyn_cast<ConstantInt>(*i))
+      for (Use &Idx : GEP->indices())
+        if (ConstantInt *C = dyn_cast<ConstantInt>(Idx))
           Operands.push_back(C->getSExtValue());
         else
           return false; // Not a constant operand GEP!
diff --git a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
index aa708ee520b17..8dc480f281055 100644
--- a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
+++ b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
@@ -698,9 +698,7 @@ bool HotColdSplitting::outlineColdRegions(Function &F, bool HasProfileSummary) {
 bool HotColdSplitting::run(Module &M) {
   bool Changed = false;
   bool HasProfileSummary = (M.getProfileSummary(/* IsCS */ false) != nullptr);
-  for (auto It = M.begin(), End = M.end(); It != End; ++It) {
-    Function &F = *It;
-
+  for (Function &F : M) {
     // Do not touch declarations.
     if (F.isDeclaration())
       continue;
diff --git a/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index b3427741903d0..91af6e0cb72e1 100644
--- a/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -529,10 +529,9 @@ void MergeFunctions::eraseInstsUnrelatedToPDI(
 // Reduce G to its entry block.
 void MergeFunctions::eraseTail(Function *G) {
   std::vector<BasicBlock *> WorklistBB;
-  for (Function::iterator BBI = std::next(G->begin()), BBE = G->end();
-       BBI != BBE; ++BBI) {
-    BBI->dropAllReferences();
-    WorklistBB.push_back(&*BBI);
+  for (BasicBlock &BB : drop_begin(*G)) {
+    BB.dropAllReferences();
+    WorklistBB.push_back(&BB);
   }
   while (!WorklistBB.empty()) {
     BasicBlock *BB = WorklistBB.back();
@@ -634,18 +633,15 @@ void MergeFunctions::filterInstsUnrelatedToPDI(
   LLVM_DEBUG(
       dbgs()
       << " Report parameter debug info related/related instructions: {\n");
-  for (BasicBlock::iterator BI = GEntryBlock->begin(), BE = GEntryBlock->end();
-       BI != BE; ++BI) {
-
-    Instruction *I = &*BI;
-    if (PDIRelated.find(I) == PDIRelated.end()) {
+  for (Instruction &I : *GEntryBlock) {
+    if (PDIRelated.find(&I) == PDIRelated.end()) {
       LLVM_DEBUG(dbgs() << "  !PDIRelated: ");
-      LLVM_DEBUG(I->print(dbgs()));
+      LLVM_DEBUG(I.print(dbgs()));
       LLVM_DEBUG(dbgs() << "\n");
-      PDIUnrelatedWL.push_back(I);
+      PDIUnrelatedWL.push_back(&I);
     } else {
       LLVM_DEBUG(dbgs() << "   PDIRelated: ");
-      LLVM_DEBUG(I->print(dbgs()));
+      LLVM_DEBUG(I.print(dbgs()));
       LLVM_DEBUG(dbgs() << "\n");
     }
   }
diff --git a/llvm/lib/Transforms/IPO/PartialInlining.cpp b/llvm/lib/Transforms/IPO/PartialInlining.cpp
index 2bbf4bf110ae9..5dfb8dab79485 100644
--- a/llvm/lib/Transforms/IPO/PartialInlining.cpp
+++ b/llvm/lib/Transforms/IPO/PartialInlining.cpp
@@ -418,12 +418,12 @@ PartialInlinerImpl::computeOutliningColdRegionsInfo(
       [&ORE](SmallVectorImpl<BasicBlock *> &BlockList) -> BasicBlock * {
     BasicBlock *ExitBlock = nullptr;
     for (auto *Block : BlockList) {
-      for (auto SI = succ_begin(Block); SI != succ_end(Block); ++SI) {
-        if (!is_contained(BlockList, *SI)) {
+      for (BasicBlock *Succ : successors(Block)) {
+        if (!is_contained(BlockList, Succ)) {
           if (ExitBlock) {
             ORE.emit([&]() {
               return OptimizationRemarkMissed(DEBUG_TYPE, "MultiExitRegion",
-                                              &SI->front())
+                                              &Succ->front())
                      << "Region dominated by "
                      << ore::NV("Block", BlockList.front()->getName())
                      << " has more than one region exit edge.";
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index a6f303428b62d..f20c34be8b192 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -1907,21 +1907,17 @@ void SampleProfileLoader::buildEdges(Function &F) {
     SmallPtrSet<BasicBlock *, 16> Visited;
     if (!Predecessors[B1].empty())
       llvm_unreachable("Found a stale predecessors list in a basic block.");
-    for (pred_iterator PI = pred_begin(B1), PE = pred_end(B1); PI != PE; ++PI) {
-      BasicBlock *B2 = *PI;
+    for (BasicBlock *B2 : predecessors(B1))
       if (Visited.insert(B2).second)
         Predecessors[B1].push_back(B2);
-    }
 
     // Add successors for B1.
     Visited.clear();
     if (!Successors[B1].empty())
       llvm_unreachable("Found a stale successors list in a basic block.");
-    for (succ_iterator SI = succ_begin(B1), SE = succ_end(B1); SI != SE; ++SI) {
-      BasicBlock *B2 = *SI;
+    for (BasicBlock *B2 : successors(B1))
       if (Visited.insert(B2).second)
         Successors[B1].push_back(B2);
-    }
   }
 }