Use MachineInstr::mop_iterator instead of MIOperands; NFC

(Const)?MIOperands is equivalent to the C++ style
MachineInstr::mop_iterator. Use the latter for consistency except for a
few callers of MIOperands::analyzePhysReg().

llvm-svn: 285029
diff --git a/llvm/lib/Target/Hexagon/HexagonGenInsert.cpp b/llvm/lib/Target/Hexagon/HexagonGenInsert.cpp
index ae45fb3..302ccad 100644
--- a/llvm/lib/Target/Hexagon/HexagonGenInsert.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonGenInsert.cpp
@@ -1444,10 +1444,10 @@
 
     bool AllDead = true;
     SmallVector<unsigned,2> Regs;
-    for (ConstMIOperands Op(*MI); Op.isValid(); ++Op) {
-      if (!Op->isReg() || !Op->isDef())
+    for (const MachineOperand &MO : MI->operands()) {
+      if (!MO.isReg() || !MO.isDef())
         continue;
-      unsigned R = Op->getReg();
+      unsigned R = MO.getReg();
       if (!TargetRegisterInfo::isVirtualRegister(R) ||
           !MRI->use_nodbg_empty(R)) {
         AllDead = false;