[Hexagon] Use default member initializations (NFC) (llvm#165653)

Identified with modernize-use-default-member-init.

Author: kazutakahirata

llvm/lib/Target/Hexagon/HexagonCopyHoisting.cpp

@@ -34,7 +34,7 @@ class HexagonCopyHoisting : public MachineFunctionPass {
 
 public:
   static char ID;
-  HexagonCopyHoisting() : MachineFunctionPass(ID), MFN(nullptr), MRI(nullptr) {}
+  HexagonCopyHoisting() : MachineFunctionPass(ID) {}
 
   StringRef getPassName() const override { return "Hexagon Copy Hoisting"; }
 
@@ -56,8 +56,8 @@ class HexagonCopyHoisting : public MachineFunctionPass {
   void moveCopyInstr(MachineBasicBlock *DestBB,
                      std::pair<Register, Register> Key, MachineInstr *MI);
 
-  MachineFunction *MFN;
-  MachineRegisterInfo *MRI;
+  MachineFunction *MFN = nullptr;
+  MachineRegisterInfo *MRI = nullptr;
   std::vector<DenseMap<std::pair<Register, Register>, MachineInstr *>>
       CopyMIList;
 };

llvm/lib/Target/Hexagon/HexagonGenMemAbsolute.cpp

@@ -34,13 +34,13 @@ STATISTIC(HexagonNumStoreAbsConversions,
 namespace {
 
 class HexagonGenMemAbsolute : public MachineFunctionPass {
-  const HexagonInstrInfo *TII;
-  MachineRegisterInfo *MRI;
-  const TargetRegisterInfo *TRI;
+  const HexagonInstrInfo *TII = nullptr;
+  MachineRegisterInfo *MRI = nullptr;
+  const TargetRegisterInfo *TRI = nullptr;
 
 public:
   static char ID;
-  HexagonGenMemAbsolute() : MachineFunctionPass(ID), TII(0), MRI(0), TRI(0) {}
+  HexagonGenMemAbsolute() : MachineFunctionPass(ID) {}
 
   StringRef getPassName() const override {
     return "Hexagon Generate Load/Store Set Absolute Address Instruction";

llvm/lib/Target/Hexagon/HexagonTfrCleanup.cpp

@@ -43,7 +43,7 @@ namespace {
 class HexagonTfrCleanup : public MachineFunctionPass {
 public:
   static char ID;
-  HexagonTfrCleanup() : MachineFunctionPass(ID), HII(0), TRI(0) {}
+  HexagonTfrCleanup() : MachineFunctionPass(ID) {}
   StringRef getPassName() const override { return "Hexagon TFR Cleanup"; }
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesAll();
@@ -52,8 +52,8 @@ class HexagonTfrCleanup : public MachineFunctionPass {
   bool runOnMachineFunction(MachineFunction &MF) override;
 
 private:
-  const HexagonInstrInfo *HII;
-  const TargetRegisterInfo *TRI;
+  const HexagonInstrInfo *HII = nullptr;
+  const TargetRegisterInfo *TRI = nullptr;
 
   typedef DenseMap<unsigned, uint64_t> ImmediateMap;