diff --git a/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index ca8bb6364e03e5..5984063627b053 100644
--- a/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -354,8 +354,7 @@ void AggressiveAntiDepBreaker::PrescanInstruction(
   // dead, or because only a subregister is live at the def. If we
   // don't do this the dead def will be incorrectly merged into the
   // previous def.
-  for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-    MachineOperand &MO = MI.getOperand(i);
+  for (const MachineOperand &MO : MI.operands()) {
     if (!MO.isReg() || !MO.isDef()) continue;
     Register Reg = MO.getReg();
     if (Reg == 0) continue;
@@ -407,8 +406,7 @@ void AggressiveAntiDepBreaker::PrescanInstruction(
 
   // Scan the register defs for this instruction and update
   // live-ranges.
-  for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-    MachineOperand &MO = MI.getOperand(i);
+  for (const MachineOperand &MO : MI.operands()) {
     if (!MO.isReg() || !MO.isDef()) continue;
     Register Reg = MO.getReg();
     if (Reg == 0) continue;
@@ -495,8 +493,7 @@ void AggressiveAntiDepBreaker::ScanInstruction(MachineInstr &MI,
     LLVM_DEBUG(dbgs() << "\tKill Group:");
 
     unsigned FirstReg = 0;
-    for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-      MachineOperand &MO = MI.getOperand(i);
+    for (const MachineOperand &MO : MI.operands()) {
       if (!MO.isReg()) continue;
       Register Reg = MO.getReg();
       if (Reg == 0) continue;
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index df629b40df6e57..19eed449db9d50 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -3732,8 +3732,7 @@ void CombinerHelper::applyExtendThroughPhis(MachineInstr &MI,
   Builder.setInstrAndDebugLoc(MI);
   auto NewPhi = Builder.buildInstrNoInsert(TargetOpcode::G_PHI);
   NewPhi.addDef(DstReg);
-  for (unsigned SrcIdx = 1; SrcIdx < MI.getNumOperands(); ++SrcIdx) {
-    auto &MO = MI.getOperand(SrcIdx);
+  for (const MachineOperand &MO : llvm::drop_begin(MI.operands())) {
     if (!MO.isReg()) {
       NewPhi.addMBB(MO.getMBB());
       continue;
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index a775f2e69a3e72..e09cd26eb0c157 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -585,8 +585,8 @@ simpleLibcall(MachineInstr &MI, MachineIRBuilder &MIRBuilder, unsigned Size,
 
   // FIXME: What does the original arg index mean here?
   SmallVector<CallLowering::ArgInfo, 3> Args;
-  for (unsigned i = 1; i < MI.getNumOperands(); i++)
-    Args.push_back({MI.getOperand(i).getReg(), OpType, 0});
+  for (const MachineOperand &MO : llvm::drop_begin(MI.operands()))
+    Args.push_back({MO.getReg(), OpType, 0});
   return createLibcall(MIRBuilder, Libcall,
                        {MI.getOperand(0).getReg(), OpType, 0}, Args);
 }
@@ -1500,8 +1500,8 @@ LegalizerHelper::widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx,
   LLT WideDstTy = LLT::scalar(NumMerge * WideSize);
 
   // Decompose the original operands if they don't evenly divide.
-  for (int I = 1, E = MI.getNumOperands(); I != E; ++I) {
-    Register SrcReg = MI.getOperand(I).getReg();
+  for (const MachineOperand &MO : llvm::drop_begin(MI.operands())) {
+    Register SrcReg = MO.getReg();
     if (GCD == SrcSize) {
       Unmerges.push_back(SrcReg);
     } else {
@@ -4037,8 +4037,8 @@ LegalizerHelper::fewerElementsVectorMerge(MachineInstr &MI, unsigned TypeIdx,
 
   // Break into a common type
   SmallVector<Register, 16> Parts;
-  for (unsigned I = 1, E = MI.getNumOperands(); I != E; ++I)
-    extractGCDType(Parts, GCDTy, MI.getOperand(I).getReg());
+  for (const MachineOperand &MO : llvm::drop_begin(MI.operands()))
+    extractGCDType(Parts, GCDTy, MO.getReg());
 
   // Build the requested new merge, padding with undef.
   LLT LCMTy = buildLCMMergePieces(DstTy, NarrowTy, GCDTy, Parts,
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index d6bb3e7c9e58b9..a34cf2e83b81cf 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -1276,11 +1276,9 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     if (DstTy.getNumElements() != MI->getNumOperands() - 1)
       report("G_BUILD_VECTOR must have an operand for each elemement", MI);
 
-    for (unsigned i = 2; i < MI->getNumOperands(); ++i) {
-      if (MRI->getType(MI->getOperand(1).getReg()) !=
-          MRI->getType(MI->getOperand(i).getReg()))
+    for (const MachineOperand &MO : llvm::drop_begin(MI->operands(), 2))
+      if (MRI->getType(MI->getOperand(1).getReg()) != MRI->getType(MO.getReg()))
         report("G_BUILD_VECTOR source operand types are not homogeneous", MI);
-    }
 
     break;
   }
@@ -1292,12 +1290,10 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     if (!DstTy.isVector() || SrcEltTy.isVector())
       report("G_BUILD_VECTOR_TRUNC must produce a vector from scalar operands",
              MI);
-    for (unsigned i = 2; i < MI->getNumOperands(); ++i) {
-      if (MRI->getType(MI->getOperand(1).getReg()) !=
-          MRI->getType(MI->getOperand(i).getReg()))
+    for (const MachineOperand &MO : llvm::drop_begin(MI->operands(), 2))
+      if (MRI->getType(MI->getOperand(1).getReg()) != MRI->getType(MO.getReg()))
         report("G_BUILD_VECTOR_TRUNC source operand types are not homogeneous",
                MI);
-    }
     if (SrcEltTy.getSizeInBits() <= DstTy.getElementType().getSizeInBits())
       report("G_BUILD_VECTOR_TRUNC source operand types are not larger than "
              "dest elt type",
@@ -1316,11 +1312,9 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     if (MI->getNumOperands() < 3)
       report("G_CONCAT_VECTOR requires at least 2 source operands", MI);
 
-    for (unsigned i = 2; i < MI->getNumOperands(); ++i) {
-      if (MRI->getType(MI->getOperand(1).getReg()) !=
-          MRI->getType(MI->getOperand(i).getReg()))
+    for (const MachineOperand &MO : llvm::drop_begin(MI->operands(), 2))
+      if (MRI->getType(MI->getOperand(1).getReg()) != MRI->getType(MO.getReg()))
         report("G_CONCAT_VECTOR source operand types are not homogeneous", MI);
-    }
     if (DstTy.getNumElements() !=
         SrcTy.getNumElements() * (MI->getNumOperands() - 1))
       report("G_CONCAT_VECTOR num dest and source elements should match", MI);
diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index e74b3195a130bd..f94b548bda3d63 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -957,8 +957,7 @@ bool TargetInstrInfo::isReallyTriviallyReMaterializableGeneric(
 
   // If any of the registers accessed are non-constant, conservatively assume
   // the instruction is not rematerializable.
-  for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI.getOperand(i);
+  for (const MachineOperand &MO : MI.operands()) {
     if (!MO.isReg()) continue;
     Register Reg = MO.getReg();
     if (Reg == 0)
diff --git a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
index b083c8f6fd55a2..627f90b834bd06 100644
--- a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -492,8 +492,7 @@ void TwoAddressInstructionPass::removeClobberedSrcRegMap(MachineInstr *MI) {
       return;
   }
 
-  for (unsigned i = 0, NumOps = MI->getNumOperands(); i != NumOps; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
+  for (const MachineOperand &MO : MI->operands()) {
     if (MO.isRegMask()) {
       removeMapRegEntry(MO, SrcRegMap, TRI);
       continue;
@@ -1335,8 +1334,7 @@ tryInstructionTransform(MachineBasicBlock::iterator &mi,
           // Success, or at least we made an improvement. Keep the unfolded
           // instructions and discard the original.
           if (LV) {
-            for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-              MachineOperand &MO = MI.getOperand(i);
+            for (const MachineOperand &MO : MI.operands()) {
               if (MO.isReg() && MO.getReg().isVirtual()) {
                 if (MO.isUse()) {
                   if (MO.isKill()) {
diff --git a/llvm/lib/Target/X86/X86DomainReassignment.cpp b/llvm/lib/Target/X86/X86DomainReassignment.cpp
index a2ae6345c006b7..9826bf4bf861f2 100644
--- a/llvm/lib/Target/X86/X86DomainReassignment.cpp
+++ b/llvm/lib/Target/X86/X86DomainReassignment.cpp
@@ -186,8 +186,8 @@ class InstrReplacerDstCOPY : public InstrConverterBase {
         TII->getRegClass(TII->get(DstOpcode), 0, MRI->getTargetRegisterInfo(),
                          *MBB->getParent()));
     MachineInstrBuilder Bld = BuildMI(*MBB, MI, DL, TII->get(DstOpcode), Reg);
-    for (unsigned Idx = 1, End = MI->getNumOperands(); Idx < End; ++Idx)
-      Bld.add(MI->getOperand(Idx));
+    for (const MachineOperand &MO : llvm::drop_begin(MI->operands()))
+      Bld.add(MO);
 
     BuildMI(*MBB, MI, DL, TII->get(TargetOpcode::COPY))
         .add(MI->getOperand(0))
diff --git a/llvm/lib/Target/X86/X86FixupLEAs.cpp b/llvm/lib/Target/X86/X86FixupLEAs.cpp
index 9a63cffe0a0920..4730b936ec1fb5 100644
--- a/llvm/lib/Target/X86/X86FixupLEAs.cpp
+++ b/llvm/lib/Target/X86/X86FixupLEAs.cpp
@@ -278,10 +278,9 @@ FixupLEAPass::usesRegister(MachineOperand &p, MachineBasicBlock::iterator I) {
   RegUsageState RegUsage = RU_NotUsed;
   MachineInstr &MI = *I;
 
-  for (unsigned i = 0; i < MI.getNumOperands(); ++i) {
-    MachineOperand &opnd = MI.getOperand(i);
-    if (opnd.isReg() && opnd.getReg() == p.getReg()) {
-      if (opnd.isDef())
+  for (const MachineOperand &MO : MI.operands()) {
+    if (MO.isReg() && MO.getReg() == p.getReg()) {
+      if (MO.isDef())
         return RU_Write;
       RegUsage = RU_Read;
     }
diff --git a/llvm/lib/Target/X86/X86FloatingPoint.cpp b/llvm/lib/Target/X86/X86FloatingPoint.cpp
index 60e1b37ed61cbd..4d9160f3522632 100644
--- a/llvm/lib/Target/X86/X86FloatingPoint.cpp
+++ b/llvm/lib/Target/X86/X86FloatingPoint.cpp
@@ -446,11 +446,9 @@ bool FPS::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) {
     // Get dead variables list now because the MI pointer may be deleted as part
     // of processing!
     SmallVector<unsigned, 8> DeadRegs;
-    for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-      const MachineOperand &MO = MI.getOperand(i);
+    for (const MachineOperand &MO : MI.operands())
       if (MO.isReg() && MO.isDead())
         DeadRegs.push_back(MO.getReg());
-    }
 
     switch (FPInstClass) {
     case X86II::ZeroArgFP:  handleZeroArgFP(I); break;
@@ -1672,8 +1670,7 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &Inst) {
     // Collect all FP registers (register operands with constraints "t", "u",
     // and "f") to kill afer the instruction.
     unsigned FPKills = ((1u << NumFPRegs) - 1) & ~0xff;
-    for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-      MachineOperand &Op = MI.getOperand(i);
+    for (const MachineOperand &Op : MI.operands()) {
       if (!Op.isReg() || Op.getReg() < X86::FP0 || Op.getReg() > X86::FP6)
         continue;
       unsigned FPReg = getFPReg(Op);
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 639aa5199ea57c..bb5637a319477d 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -1163,8 +1163,7 @@ void X86InstrInfo::reMaterialize(MachineBasicBlock &MBB,
 
 /// True if MI has a condition code def, e.g. EFLAGS, that is not marked dead.
 bool X86InstrInfo::hasLiveCondCodeDef(MachineInstr &MI) const {
-  for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
-    MachineOperand &MO = MI.getOperand(i);
+  for (const MachineOperand &MO : MI.operands()) {
     if (MO.isReg() && MO.isDef() &&
         MO.getReg() == X86::EFLAGS && !MO.isDead()) {
       return true;
@@ -5676,10 +5675,8 @@ static MachineInstr *FuseTwoAddrInst(MachineFunction &MF, unsigned Opcode,
     MachineOperand &MO = MI.getOperand(i + 2);
     MIB.add(MO);
   }
-  for (unsigned i = NumOps + 2, e = MI.getNumOperands(); i != e; ++i) {
-    MachineOperand &MO = MI.getOperand(i);
+  for (const MachineOperand &MO : llvm::drop_begin(MI.operands(), NumOps + 2))
     MIB.add(MO);
-  }
 
   updateOperandRegConstraints(MF, *NewMI, TII);