diff --git a/src/IR.cpp b/src/IR.cpp
index 540f974..5f4e0c5 100644
--- a/src/IR.cpp
+++ b/src/IR.cpp
@@ -102,30 +102,54 @@ void Value::replaceAllUsesWith(Value *value) {
   uses.clear();
 }
 
-ConstantValue* ConstantValue::get(int value) {
-  static std::map<int, std::unique_ptr<ConstantValue>> intConstants;
-  auto iter = intConstants.find(value);
-  if (iter != intConstants.end()) {
-    return iter->second.get();
+
+// Implementations for static members
+
+std::unordered_map<ConstantValueKey, ConstantValue*, ConstantValueHash, ConstantValueEqual> ConstantValue::mConstantPool;
+std::unordered_map<Type*, UndefinedValue*> UndefinedValue::UndefValues;
+
+ConstantValue* ConstantValue::get(Type* type, ConstantValVariant val) {
+  ConstantValueKey key = {type, val};
+  auto it = mConstantPool.find(key);
+  if (it != mConstantPool.end()) {
+    return it->second;
   }
-  auto inst = new ConstantValue(value);
-  assert(inst);
-  auto result = intConstants.emplace(value, inst);
-  return result.first->second.get();
+
+  ConstantValue* newConstant = nullptr;
+  if (std::holds_alternative<int>(val)) {
+    newConstant = new ConstantInteger(type, std::get<int>(val));
+  } else if (std::holds_alternative<float>(val)) {
+    newConstant = new ConstantFloating(type, std::get<float>(val));
+  } else {
+    assert(false && "Unsupported ConstantValVariant type");
+  }
+
+  mConstantPool[key] = newConstant;
+  return newConstant;
 }
 
-ConstantValue* ConstantValue::get(float value) {
-  static std::map<float, std::unique_ptr<ConstantValue>> floatConstants;
-  auto iter = floatConstants.find(value);
-  if (iter != floatConstants.end()) {
-    return iter->second.get();
-  }
-  auto inst = new ConstantValue(value);
-  assert(inst);
-  auto result = floatConstants.emplace(value, inst);
-  return result.first->second.get();
+ConstantInteger* ConstantInteger::get(Type* type, int val) {
+  return dynamic_cast<ConstantInteger*>(ConstantValue::get(type, val));
 }
 
+ConstantFloating* ConstantFloating::get(Type* type, float val) {
+  return dynamic_cast<ConstantFloating*>(ConstantValue::get(type, val));
+}
+
+UndefinedValue* UndefinedValue::get(Type* type) {
+  assert(!type->isVoid() && "Cannot get UndefinedValue of void type!");
+
+  auto it = UndefValues.find(type);
+  if (it != UndefValues.end()) {
+    return it->second;
+  }
+
+  UndefinedValue* newUndef = new UndefinedValue(type);
+  UndefValues[type] = newUndef;
+  return newUndef;
+}
+
+
 auto Function::getCalleesWithNoExternalAndSelf() -> std::set<Function *> {
   std::set<Function *> result;
   for (auto callee : callees) {
@@ -545,6 +569,83 @@ void User::replaceOperand(unsigned index, Value *value) {
   value->addUse(use);
 }
 
+/**
+ * phi相关函数
+ */
+
+ Value* PhiInst::getvalfromBlk(BasicBlock* blk){
+  refreshB2VMap();
+  if( blk2val.find(blk) != blk2val.end()) {
+    return blk2val.at(blk);
+  }
+  return nullptr;
+}
+
+BasicBlock* PhiInst::getBlkfromVal(Value* val){
+  // 返回第一个值对应的基本块
+  for(unsigned i = 0; i < vsize; i++) {
+    if(getValue(i) == val) {
+      return getBlock(i);
+    }
+  }
+  return nullptr;
+}
+
+void PhiInst::delValue(Value* val){
+  //根据value删除对应的基本块和值
+  unsigned i = 0;
+  BasicBlock* blk = getBlkfromVal(val);
+  for(i = 0; i < vsize; i++) {
+    if(getValue(i) == val) {
+      break;
+    }
+  }
+  removeOperand(2 * i + 1); // 删除blk
+  removeOperand(2 * i); // 删除val
+  vsize--;
+  blk2val.erase(blk); // 删除blk2val映射
+}
+
+void PhiInst::delBlk(BasicBlock* blk){
+  //根据Blk删除对应的基本块和值
+  unsigned i = 0;
+  Value* val = getvalfromBlk(blk);
+  for(i = 0; i < vsize; i++) {
+    if(getBlock(i) == blk) {
+      break;
+    }
+  }
+  removeOperand(2 * i + 1); // 删除blk
+  removeOperand(2 * i); // 删除val
+  vsize--;
+  blk2val.erase(blk); // 删除blk2val映射
+}
+
+void PhiInst::replaceBlk(BasicBlock* newBlk, unsigned k){
+  refreshB2VMap();
+  Value* val = blk2val.at(getBlock(k));
+  // 替换基本块
+  setOperand(2 * k + 1, newBlk);
+  // 替换blk2val映射
+  blk2val.erase(getBlock(k));
+  blk2val.emplace(newBlk, val);
+}
+
+void PhiInst::replaceold2new(BasicBlock* oldBlk, BasicBlock* newBlk){
+  refreshB2VMap();
+  Value* val = blk2val.at(oldBlk);
+  // 替换基本块
+  delBlk(oldBlk);
+  addIncoming(val, newBlk);
+}
+
+void PhiInst::refreshB2VMap(){
+  blk2val.clear();
+  for(unsigned i = 0; i < vsize; i++) {
+    blk2val.emplace(getBlock(i), getValue(i));
+  }
+}
+
 CallInst::CallInst(Function *callee, const std::vector<Value *> &args, BasicBlock *parent, const std::string &name)
     : Instruction(kCall, callee->getReturnType(), parent, name) {
   addOperand(callee);
diff --git a/src/include/IR.h b/src/include/IR.h
index 1b4c702..060bdc5 100644
--- a/src/include/IR.h
+++ b/src/include/IR.h
@@ -268,6 +268,51 @@ class ValueCounter {
   }  ///< 清空ValueCounter
 };
 
+
+// --- Refactored ConstantValue and related classes start here ---
+
+using ConstantValVariant = std::variant<int, float>;
+
+// Helper for hashing std::variant
+struct VariantHash {
+  template <class T>
+  std::size_t operator()(const T& val) const {
+    return std::hash<T>{}(val);
+  }
+  std::size_t operator()(const ConstantValVariant& v) const {
+    return std::visit(*this, v);
+  }
+};
+
+struct ConstantValueKey {
+  Type* type;
+  ConstantValVariant val;
+
+  bool operator==(const ConstantValueKey& other) const {
+    // Assuming Type objects are canonicalized, or add Type::isSame()
+    // If Type::isSame() is not available and Type objects are not canonicalized,
+    // this comparison might not be robust enough for structural equivalence of types.
+    return type == other.type && val == other.val;
+  }
+};
+
+struct ConstantValueHash {
+  std::size_t operator()(const ConstantValueKey& key) const {
+    std::size_t typeHash = std::hash<Type*>{}(key.type);
+    std::size_t valHash = VariantHash{}(key.val);
+    // A simple way to combine hashes
+    return typeHash ^ (valHash << 1);
+  }
+};
+
+struct ConstantValueEqual {
+  bool operator()(const ConstantValueKey& lhs, const ConstantValueKey& rhs) const {
+    // Assuming Type objects are canonicalized (e.g., Type::getIntType() always returns same pointer)
+    // If not, and Type::isSame() is intended, it should be added to Type class.
+    return lhs.type == rhs.type && lhs.val == rhs.val;
+  }
+};
+
 /*!
  * Static constants known at compile time.
  *
@@ -276,45 +321,135 @@ class ValueCounter {
  * `ConstantValue`并不由指令定义, 也不使用任何Value。它的类型为int/float。
  */
 
+template<class T> struct always_false : std::false_type {};
+template<class T> constexpr bool always_false_v = always_false<T>::value;
 
 class ConstantValue : public Value {
- protected:
-  /// 定义字面量类型的聚合类型
-  union {
-    int iScalar;
-    float fScalar;
-  };
+protected:
+  static std::unordered_map<ConstantValueKey, ConstantValue*, ConstantValueHash, ConstantValueEqual> mConstantPool;
 
- protected:
-  explicit ConstantValue(int value, const std::string &name = "") : Value(Type::getIntType(), name), iScalar(value) {}
-  explicit ConstantValue(float value, const std::string &name = "")
-      : Value(Type::getFloatType(), name), fScalar(value) {}
+public:
+  explicit ConstantValue(Type* type, const std::string& name = "") : Value(type, name) {}
+  virtual ~ConstantValue() = default;
 
- public:
-  static ConstantValue* get(int value);    ///< 获取一个int类型的ConstValue *，其值为value
-  static ConstantValue* get(float value);  ///< 获取一个float类型的ConstValue *，其值为value
+  virtual size_t hash() const = 0;
+  virtual ConstantValVariant getVal() const = 0;
 
- public:
+  // Static factory method to get a canonical ConstantValue from the pool
+  static ConstantValue* get(Type* type, ConstantValVariant val);
+
+  // Helper methods to access constant values with appropriate casting
   int getInt() const {
-    assert(isInt());
-    return iScalar;
-  }  ///< 返回int类型的值
+    assert(getType()->isInt() && "Calling getInt() on non-integer type");
+    return std::get<int>(getVal());
+  }
   float getFloat() const {
-    assert(isFloat());
-    return fScalar;
-  }  ///< 返回float类型的值
-  template <typename T>
-  T getValue() const {
-    if (std::is_same<T, int>::value && isInt()) {
+    assert(getType()->isFloat() && "Calling getFloat() on non-float type");
+    return std::get<float>(getVal());
+  }
+
+  template<typename T>
+  T getVal() const {
+    if constexpr (std::is_same_v<T, int>) {
       return getInt();
-    }
-    if (std::is_same<T, float>::value && isFloat()) {
+    } else if constexpr (std::is_same_v<T, float>) {
       return getFloat();
+    } else {
+      // This ensures a compilation error if an unsupported type is used
+      static_assert(always_false_v<T>, "Unsupported type for ConstantValue::getValue()");
     }
-    throw std::bad_cast();  // 或者其他适当的异常处理
-  }                         ///< 返回值，getInt和getFloat统一化，整数返回整形，浮点返回浮点型
+  }
+
+  virtual bool isZero() const = 0;
+  virtual bool isOne() const = 0;
 };
 
+class ConstantInteger : public ConstantValue {
+  int constVal;
+public:
+  explicit ConstantInteger(Type* type, int val, const std::string& name = "")
+      : ConstantValue(type, name), constVal(val) {}
+
+  size_t hash() const override {
+      std::size_t typeHash = std::hash<Type*>{}(getType());
+      std::size_t valHash = std::hash<int>{}(constVal);
+      return typeHash ^ (valHash << 1);
+  }
+  int getInt() const { return constVal; }
+  ConstantValVariant getVal() const override { return constVal; }
+
+  static ConstantInteger* get(Type* type, int val);
+  static ConstantInteger* get(int val) { return get(Type::getIntType(), val); }
+
+  ConstantInteger* getNeg() const {
+    assert(getType()->isInt() && "Cannot negate non-integer constant");
+    return ConstantInteger::get(-constVal);
+  }
+
+  bool isZero() const override { return constVal == 0; }
+  bool isOne() const override { return constVal == 1; }
+};
+
+class ConstantFloating : public ConstantValue {
+  float constFVal;
+public:
+  explicit ConstantFloating(Type* type, float val, const std::string& name = "")
+      : ConstantValue(type, name), constFVal(val) {}
+
+  size_t hash() const override {
+    std::size_t typeHash = std::hash<Type*>{}(getType());
+    std::size_t valHash = std::hash<float>{}(constFVal);
+    return typeHash ^ (valHash << 1);
+  }
+  float getFloat() const { return constFVal; }
+  ConstantValVariant getVal() const override { return constFVal; }
+
+  static ConstantFloating* get(Type* type, float val);
+  static ConstantFloating* get(float val) { return get(Type::getFloatType(), val); }
+
+  ConstantFloating* getNeg() const {
+    assert(getType()->isFloat() && "Cannot negate non-float constant");
+    return ConstantFloating::get(-constFVal);
+  }
+
+  bool isZero() const override { return constFVal == 0.0f; }
+  bool isOne() const override { return constFVal == 1.0f; }
+};
+
+class UndefinedValue : public ConstantValue {
+private:
+  static std::unordered_map<Type*, UndefinedValue*> UndefValues;
+
+protected:
+  explicit UndefinedValue(Type* type, const std::string& name = "")
+      : ConstantValue(type, name) {
+    assert(!type->isVoid() && "Cannot create UndefinedValue of void type!");
+  }
+
+public:
+  static UndefinedValue* get(Type* type);
+
+  size_t hash() const override {
+    return std::hash<Type*>{}(getType());
+  }
+
+  ConstantValVariant getVal() const override {
+    if (getType()->isInt()) {
+      return 0; // Return 0 for undefined integer
+    } else if (getType()->isFloat()) {
+      return 0.0f; // Return 0.0f for undefined float
+    }
+    assert(false && "UndefinedValue has unexpected type for getValue()");
+    return 0; // Should not be reached
+  }
+
+  bool isZero() const override { return false; }
+  bool isOne() const override { return false; }
+};
+
+// --- End of refactored ConstantValue and related classes ---
+
+
 class Instruction;
 class Function;
 class BasicBlock;
@@ -562,8 +697,8 @@ class Instruction : public User {
     kLa = 0x1UL << 36,
     kMemset = 0x1UL << 37,
     kGetSubArray = 0x1UL << 38,
-    // constant
-    kConstant = 0x1UL << 37, 
+    // Constant Kind removed as Constants are now Values, not Instructions.
+    // kConstant = 0x1UL << 37, // Conflicts with kMemset if kept as is
     // phi
     kPhi = 0x1UL << 39,
     kBitItoF = 0x1UL << 40,
@@ -755,24 +890,51 @@ class LaInst : public Instruction {
 class PhiInst : public Instruction {
   friend class IRBuilder;
   friend class Function;
-  friend class SysySSA;
 
  protected:
-  Value *map_val;  // Phi的旧值
 
-  PhiInst(Type *type, Value *lhs, const std::vector<Value *> &rhs, Value *mval, BasicBlock *parent,
+  std::unordered_map<BasicBlock *, Value *> blk2val;  ///< 存储每个基本块对应的值
+  unsigned vsize;  ///< 存储值的数量
+
+  PhiInst(Type *type, 
+          const std::vector<Value *> &rhs = {}, 
+          const std::vector<BasicBlock*> &Blocks = {},
+          BasicBlock *parent = nullptr,
           const std::string &name = "")
-      : Instruction(Kind::kPhi, type, parent, name) {
-    map_val = mval;
-    addOperand(lhs);
-    addOperands(rhs);
+      : Instruction(Kind::kPhi, type, parent, name), vsize(rhs.size()) {
+    assert(rhs.size() == Blocks.size() && "PhiInst: rhs and Blocks must have the same size");
+    for(size_t i = 0; i < rhs.size(); ++i) {
+      addOperand(rhs[i]);
+      blk2val[Blocks[i]] = rhs[i];
+    }
   }
 
  public:
-  Value* getMapVal() { return map_val; }
-  Value* getPointer() const { return getOperand(0); }
+  Value* getValue(unsigned k) const {return getOperand(2 * k);}  ///< 获取位置为k的值
+  BasicBlock* getBlock(unsigned k) const {return dynamic_cast<BasicBlock*>(getOperand(2 * k + 1));}
+
+  auto& getincomings() const {return blk2val;}  ///< 获取所有的基本块和对应的值
+
+  Value* getvalfromBlk(BasicBlock* blk);
+  BasicBlock* getBlkfromVal(Value* val);
+
+  unsigned getNumIncomingValues() const { return vsize; }  ///< 获取传入值的数量
+  void addIncoming(Value *value, BasicBlock *block) {
+    assert(value && block && "PhiInst: value and block must not be null");
+    addOperand(value);
+    addOperand(block);
+    blk2val[block] = value;
+    vsize++;
+  }  ///< 添加传入值和对应的基本块
+
+  void delValue(Value* val);
+  void delBlk(BasicBlock* blk);
+
+  void replaceBlk(BasicBlock* newBlk, unsigned k);
+  void replaceold2new(BasicBlock* oldBlk, BasicBlock* newBlk);
+  void refreshB2VMap();
+
   auto getValues() { return make_range(std::next(operand_begin()), operand_end()); }
-  Value* getValue(unsigned index) const { return getOperand(index + 1); }
 };
 
 
@@ -884,7 +1046,7 @@ public:
     }
   }  ///< 根据指令类型进行二元计算，eval template模板实现
   static BinaryInst* create(Kind kind, Type *type, Value *lhs, Value *rhs, BasicBlock *parent, const std::string &name = "") {
-        // 后端处理数组访存操作时需要创建计算地址的指令，需要在外部构造 BinaryInst 对象，所以写了个public的方法。
+        // 后端处理数组访存操作时需要创建计算地址的指令，需要在外部构造 BinaryInst 对象
         return new BinaryInst(kind, type, lhs, rhs, parent, name);
   }
 }; // class BinaryInst
@@ -1230,12 +1392,15 @@ protected:
     if (init.size() == 0) {
       unsigned num = 1;
       for (unsigned i = 0; i < numDims; i++) {
-        num *= dynamic_cast<ConstantValue *>(dims[i])->getInt();
+        // Assume dims elements are ConstantInteger and cast appropriately
+        auto dim_val = dynamic_cast<ConstantInteger*>(dims[i]);
+        assert(dim_val && "GlobalValue dims must be constant integers");
+        num *= dim_val->getInt();
       }
       if (dynamic_cast<PointerType *>(type)->getBaseType() == Type::getFloatType()) {
-        init.push_back(ConstantValue::get(0.0F), num);
+        init.push_back(ConstantFloating::get(0.0F), num); // Use new constant factory
       } else {
-        init.push_back(ConstantValue::get(0), num);
+        init.push_back(ConstantInteger::get(0), num); // Use new constant factory
       }
     }
     initValues = init;
@@ -1261,8 +1426,11 @@ public:
    Value* getByIndices(const std::vector<Value *> &indices) const  {
     int index = 0;
     for (size_t i = 0; i < indices.size(); i++) {
-      index = dynamic_cast<ConstantValue *>(getDim(i))->getInt() * index +
-              dynamic_cast<ConstantValue *>(indices[i])->getInt();
+      // Ensure dims[i] and indices[i] are ConstantInteger and retrieve their values correctly
+      auto dim_val = dynamic_cast<ConstantInteger*>(getDim(i));
+      auto idx_val = dynamic_cast<ConstantInteger*>(indices[i]);
+      assert(dim_val && idx_val && "Dims and indices must be constant integers");
+      index = dim_val->getInt() * index + idx_val->getInt();
     }
     return getByIndex(index);
   }  ///< 通过多维索引indices获取初始值
@@ -1303,8 +1471,11 @@ class ConstantVariable : public User, public LVal {
     int index = 0;
     // 计算偏移量
     for (size_t i = 0; i < indices.size(); i++) {
-      index = dynamic_cast<ConstantValue *>(getDim(i))->getInt() * index +
-              dynamic_cast<ConstantValue *>(indices[i])->getInt();
+      // Ensure dims[i] and indices[i] are ConstantInteger and retrieve their values correctly
+      auto dim_val = dynamic_cast<ConstantInteger*>(getDim(i));
+      auto idx_val = dynamic_cast<ConstantInteger*>(indices[i]);
+      assert(dim_val && idx_val && "Dims and indices must be constant integers");
+      index = dim_val->getInt() * index + idx_val->getInt();
     }
 
     return getByIndex(index);
diff --git a/src/include/IRBuilder.h b/src/include/IRBuilder.h
index aab9a1d..6df82e7 100644
--- a/src/include/IRBuilder.h
+++ b/src/include/IRBuilder.h
@@ -333,15 +333,11 @@ class IRBuilder {
     block->getInstructions().emplace(position, inst);
     return inst;
   }  ///< 创建store指令
-  PhiInst * createPhiInst(Type *type, Value *lhs, BasicBlock *parent, const std::string &name = "") {
-    auto predNum = parent->getNumPredecessors();
-    std::vector<Value *> rhs;
-    for (size_t i = 0; i < predNum; i++) {
-      rhs.push_back(lhs);
-    }
-    auto inst = new PhiInst(type, lhs, rhs, lhs, parent, name);
+  PhiInst * createPhiInst(Type *type, const std::vector<Value*> &vals = {}, const std::vector<BasicBlock*> &blks = {}, const std::string &name = "") {
+    auto predNum = block->getNumPredecessors();
+    auto inst = new PhiInst(type, vals, blks, block, name);
     assert(inst);
-    parent->getInstructions().emplace(parent->begin(), inst);
+    block->getInstructions().emplace(block->begin(), inst);
     return inst;
   }  ///< 创建Phi指令
 };