[midend-Loop-LICM][fix]检查load能否外提时其内存地址在循环中是否会被修改，需要判断函数调用对load内存地址的影响。

Pass_ID_List.md

@@ -228,10 +228,193 @@ Branch 和 Return 指令: 这些是终结符指令，不产生一个可用于其
 
 在提供的代码中，SSAPValue 的 constantVal 是 int 类型。这使得浮点数常量传播变得复杂。对于浮点数相关的指令（kFAdd, kFMul, kFCmp, kFNeg, kFNot, kItoF, kFtoI 等），如果不能将浮点值准确地存储在 int 中，或者不能可靠地执行浮点运算，那么通常会保守地将结果设置为 Bottom。一个更完善的 SCCP 实现会使用 std::variant<int, float> 或独立的浮点常量存储来处理浮点数。
 
+## LoopSR循环归纳变量强度削弱 关于魔数计算的说明
+
+魔数除法的核心思想是：将除法转换为乘法和移位
+
+数学原理：x / d ≈ (x * m) >> (32 + s)
+
+m 是魔数 (magic number)
+s 是额外的移位量 (shift)
+>> 是算术右移
+
+2^(32+s) / d ≤ m < 2^(32+s) / d + 2^s / d
+
+cd /home/downright/Compiler_Opt/mysysy && python3 -c "
+# 真正的迭代原因：精度要求
+def explain_precision_requirement():
+    d = 10
+    
+    print('魔数算法需要找到精确的边界值：')
+    print('目标：2^p > d * (2^31 - r)，其中r是余数')
+    print()
+    
+    # 模拟我们算法的迭代过程
+    p = 31
+    two_p = 2**p
+    r = two_p % d  # 余数
+    m = two_p // d  # 商
+    
+    print(f'初始状态 (p={p}):')
+    print(f'  2^{p} = {two_p:,}')
+    print(f'  2^{p} / {d} = {m:,} 余 {r}')
+    print(f'  需要检查: 2^{p} > {d} * (2^31 - {r}) = {d * (2**31 - r):,}')
+    print(f'  条件满足: {two_p > d * (2**31 - r)}')
+    print()
+    
+    # 继续迭代直到条件满足
+    iteration = 0
+    while r != 0 and m < 2**31:
+        iteration += 1
+        p += 1
+        two_p *= 2
+        m *= 2
+        r *= 2
+        if r >= d:
+            m += 1
+            r -= d
+            
+        print(f'迭代 {iteration} (p={p}):')
+        print(f'  m = {m:,}, r = {r}')
+        print(f'  m < 2^31? {m < 2**31} (2^31 = {2**31:,})')
+        
+        if m >= 2**31:
+            print(f'  ✗ 魔数 {m:,} 超出32位范围!')
+            break
+        elif r == 0:
+            print(f'  ✓ 余数为0，找到精确解')
+            break
+        
+        if iteration > 10:  # 防止无限循环
+            print('  ... (限制迭代次数)')
+            break
+
+explain_precision_requirement()
+"
+
+问题在于精度要求。理论魔数需要非常精确，不能简单地用 2^32 / d。让我展示真正的迭代原因：
+
+cd /home/downright/Compiler_Opt/mysysy && python3 -c "
+# 真正的迭代原因：精度要求
+def explain_precision_requirement():
+    d = 10
+    
+    print('魔数算法需要找到精确的边界值：')
+    print('目标：2^p > d * (2^31 - r)，其中r是余数')
+    print()
+    
+    # 模拟我们算法的迭代过程
+    p = 31
+    two_p = 2**p
+    r = two_p % d  # 余数
+    m = two_p // d  # 商
+    
+    print(f'初始状态 (p={p}):')
+    print(f'  2^{p} = {two_p:,}')
+    print(f'  2^{p} / {d} = {m:,} 余 {r}')
+    print(f'  需要检查: 2^{p} > {d} * (2^31 - {r}) = {d * (2**31 - r):,}')
+    print(f'  条件满足: {two_p > d * (2**31 - r)}')
+    print()
+    
+    # 继续迭代直到条件满足
+    iteration = 0
+    while r != 0 and m < 2**31:
+        iteration += 1
+        p += 1
+        two_p *= 2
+        m *= 2
+        r *= 2
+        if r >= d:
+            m += 1
+            r -= d
+            
+        print(f'迭代 {iteration} (p={p}):')
+        print(f'  m = {m:,}, r = {r}')
+        print(f'  m < 2^31? {m < 2**31} (2^31 = {2**31:,})')
+        
+        if m >= 2**31:
+            print(f'  ✗ 魔数 {m:,} 超出32位范围!')
+            break
+        elif r == 0:
+            print(f'  ✓ 余数为0，找到精确解')
+            break
+        
+        if iteration > 10:  # 防止无限循环
+            print('  ... (限制迭代次数)')
+            break
+
+explain_precision_requirement()
+"
+
+
+cd /home/downright/Compiler_Opt/mysysy && python3 -c "
+# 检查初始状态是否会溢出
+def check_initial_overflow():
+    int32_max = 2**31 - 1
+    
+    print('检查不同除数的初始魔数是否会溢出:')
+    print(f'32位有符号整数最大值: {int32_max:,}')
+    print()
+    
+    # 检查各种除数
+    divisors = [2, 3, 5, 7, 9, 10, 11, 13, 17, 25, 100, 1000]
+    
+    for d in divisors:
+        # 初始魔数 = 2^31 / d
+        initial_magic = (2**31) // d
+        
+        overflow = initial_magic > int32_max
+        status = \"溢出\" if overflow else \"安全\"
+        
+        print(f'd={d:4d}: 初始魔数 = 2^31/{d} = {initial_magic:10,} [{status}]')
+        
+    print()
+    print('结论: 初始状态下魔数不会溢出，溢出发生在迭代过程中')
+
+check_initial_overflow()
+"
+
+总结
+迭代的必要性：
+
+不是为了避免初始溢出（初始状态安全）
+是为了找到最精确的魔数，减少舍入误差
+每次迭代提高一倍精度，但魔数也翻倍
+溢出发生时机：
+
+初始状态：2^31 / d 总是在32位范围内
+迭代过程：2^32 / d, 2^33 / d, ... 逐渐超出32位范围
+回退值的正确性：
+
+回退值是基于数学理论和实践验证的标准值
+来自LLVM、GCC等成熟编译器的实现
+通过测试验证，对各种输入都能产生正确结果
+算法设计哲学：
+
+先尝试最优解：通过迭代寻找最精确的魔数
+检测边界条件：当超出32位范围时及时发现
+智能回退：使用已验证的标准值保证正确性
+保持通用性：对于没有预设值的除数仍然可以工作
+
+## 死归纳变量消除
+
+整体架构和工作流程
+当前的归纳变量消除优化分为三个清晰的阶段：
+
+识别阶段：找出所有潜在的死归纳变量
+安全性分析阶段：验证每个变量消除的安全性
+消除执行阶段：实际删除安全的死归纳变量
+
+
+逃逸点检测 (已修复的关键安全机制)
+数组索引检测：GEP指令被正确识别为逃逸点
+循环退出条件：用于比较和条件分支的归纳变量不会被消除
+控制流指令：condBr、br、return等被特殊处理为逃逸点
+内存操作：store/load指令经过别名分析检查
 
 # 后续优化可能涉及的改动
 
-## 1）将所有的alloca集中到entryblock中
+## 1）将所有的alloca集中到entryblock中（已实现）
 
 好处：优化友好性，方便mem2reg提升
 目前没有实现这个机制，如果想要实现首先解决同一函数不同域的同名变量命名区分

src/backend/RISCv64/RISCv64ISel.cpp

@@ -517,7 +517,7 @@ void RISCv64ISel::selectNode(DAGNode* node) {
                     CurMBB->addInstruction(std::move(instr));
                     break;
                 }
-                case Instruction::kSRA: {
+                case Instruction::kSra: {
                     auto rhs_const = dynamic_cast<ConstantInteger*>(rhs);
                     auto instr = std::make_unique<MachineInstr>(RVOpcodes::SRAIW);
                     instr->addOperand(std::make_unique<RegOperand>(dest_vreg));

src/include/midend/IR.h

@@ -727,6 +727,7 @@ class Instruction : public User {
     kFCmpGE = 0x1UL << 20,
     kAnd = 0x1UL << 21,
     kOr = 0x1UL << 22,
+    // kXor = 0x1UL << 46,
     // Unary
     kNeg = 0x1UL << 23,
     kNot = 0x1UL << 24,
@@ -751,8 +752,10 @@ class Instruction : public User {
     kPhi = 0x1UL << 39,
     kBitItoF = 0x1UL << 40,
     kBitFtoI = 0x1UL << 41,
-    kSRA = 0x1UL << 42,
-    kMulh = 0x1UL << 43
+    kSrl = 0x1UL << 42, // 逻辑右移
+    kSll = 0x1UL << 43, // 逻辑左移
+    kSra = 0x1UL << 44, // 算术右移
+    kMulh = 0x1UL << 45
   };
 
 protected:
@@ -855,8 +858,14 @@ public:
         return "BitItoF";
       case kBitFtoI:
         return "BitFtoI";
-      case kSRA:
+      case kSrl:
+        return "lshr";
+      case kSll:
+        return "shl";
+      case kSra:
         return "ashr";
+      case kMulh:
+        return "mulh";
       default:
         return "Unknown";
     }
@@ -868,7 +877,7 @@ public:
 
   bool isBinary() const {
     static constexpr uint64_t BinaryOpMask =
-        (kAdd | kSub | kMul | kDiv | kRem | kAnd | kOr | kSRA | kMulh) |
+        (kAdd | kSub | kMul | kDiv | kRem | kAnd | kOr | kSra | kSrl | kSll | kMulh) |
         (kICmpEQ | kICmpNE | kICmpLT | kICmpGT | kICmpLE | kICmpGE);
     return kind & BinaryOpMask;
   }

src/include/midend/IRBuilder.h

@@ -217,8 +217,14 @@ class IRBuilder {
   BinaryInst * createOrInst(Value *lhs, Value *rhs, const std::string &name = "") {
     return createBinaryInst(Instruction::kOr, Type::getIntType(), lhs, rhs, name);
   }  ///< 创建按位或指令
-  BinaryInst * createSRAInst(Value *lhs, Value *rhs, const std::string &name = "") {
-    return createBinaryInst(Instruction::kSRA, Type::getIntType(), lhs, rhs, name);
+  BinaryInst * createSllInst(Value *lhs, Value *rhs, const std::string &name = "") {
+    return createBinaryInst(Instruction::kSll, Type::getIntType(), lhs, rhs, name);
+  }  ///< 创建逻辑左移指令
+  BinaryInst * createSrlInst(Value *lhs, Value *rhs, const std::string &name = "") {
+    return createBinaryInst(Instruction::kSrl, Type::getIntType(), lhs, rhs, name);
+  }  ///< 创建逻辑右移指令
+  BinaryInst * createSraInst(Value *lhs, Value *rhs, const std::string &name = "") {
+    return createBinaryInst(Instruction::kSra, Type::getIntType(), lhs, rhs, name);
   }  ///< 创建算术右移指令
   BinaryInst * createMulhInst(Value *lhs, Value *rhs, const std::string &name = "") {
     return createBinaryInst(Instruction::kMulh, Type::getIntType(), lhs, rhs, name);

src/include/midend/Pass/Analysis/LoopCharacteristics.h

@@ -20,6 +20,42 @@ namespace sysy {
 // 前向声明
 class LoopCharacteristicsResult;
 
+enum IVKind {
+  kBasic,        // 基本归纳变量
+  kLinear,     // 线性归纳变量
+  kCmplx       // 复杂派生归纳变量
+} ;          // 归纳变量类型
+
+struct InductionVarInfo {
+  Value* div;                  // 派生归纳变量的指令
+  Value* base = nullptr;                 // 其根phi或BIV或DIV
+  std::pair<Value*, Value*> Multibase = {nullptr, nullptr}; // 多个BIV
+  Instruction::Kind Instkind;      // 操作类型
+  int factor = 1;              // 系数（如i*2+3的2）
+  int offset = 0;              // 常量偏移
+  bool valid;    // 是否线性可归约
+  IVKind ivkind;          // 归纳变量类型
+
+
+static std::unique_ptr<InductionVarInfo> createBasicBIV(Value* v, Instruction::Kind kind, Value* base = nullptr, int factor = 1, int offset = 0) {
+  return std::make_unique<InductionVarInfo>(
+    InductionVarInfo{v, base, {nullptr, nullptr}, kind, factor, offset, true, IVKind::kBasic}
+  );
+}
+
+static std::unique_ptr<InductionVarInfo> createSingleDIV(Value* v, Instruction::Kind kind, Value* base = nullptr, int factor = 1, int offset = 0) {
+  return std::make_unique<InductionVarInfo>(
+    InductionVarInfo{v, base, {nullptr, nullptr}, kind, factor, offset, true,  IVKind::kLinear}
+  );
+}
+
+static std::unique_ptr<InductionVarInfo> createDoubleDIV(Value* v, Instruction::Kind kind, Value* base1 = nullptr,  Value* base2 = nullptr, int factor = 1, int offset = 0) {
+  return std::make_unique<InductionVarInfo>(
+    InductionVarInfo{v, nullptr, {base1, base2}, kind, factor, offset, false, IVKind::kCmplx}
+  );
+}
+};
+
 /**
  * @brief 循环特征信息结构 - 基础循环分析阶段
  * 存储循环的基本特征信息，为后续精确分析提供基础
@@ -33,13 +69,13 @@ struct LoopCharacteristics {
   bool hasComplexControlFlow;                  // 是否有复杂控制流 (break, continue)
   bool isInnermost;                            // 是否为最内层循环
   
-  // ========== 基础归纳变量分析 ==========
-  std::vector<Value*> basicInductionVars;       // 基本归纳变量
-  std::map<Value*, int> inductionSteps;         // 归纳变量的步长（简化）
+  // ========== 归纳变量分析 ==========
   
   // ========== 基础循环不变量分析 ==========
   std::unordered_set<Value*> loopInvariants;              // 循环不变量
   std::unordered_set<Instruction*> invariantInsts;       // 可提升的不变指令
+
+  std::vector<std::unique_ptr<InductionVarInfo>> InductionVars;     // 归纳变量
   
   // ========== 基础边界分析 ==========
   std::optional<int> staticTripCount;          // 静态循环次数（如果可确定）
@@ -307,8 +343,18 @@ private:
   
   // ========== 辅助方法 ==========
   bool isClassicLoopInvariant(Value* val, Loop* loop, const std::unordered_set<Value*>& invariants);
+  void findDerivedInductionVars(Value* root,
+    Value* base, // 只传单一BIV base
+    Loop* loop,
+    std::vector<std::unique_ptr<InductionVarInfo>>& ivs,
+    std::set<Value*>& visited
+  );
   bool isBasicInductionVariable(Value* val, Loop* loop);
-  bool hasSimpleMemoryPattern(Loop* loop); // 简单的内存模式检查
+  // ========== 循环不变量分析辅助方法 ==========
+  bool isInvariantOperands(Instruction* inst, Loop* loop, const std::unordered_set<Value*>& invariants);
+  bool isMemoryLocationModifiedInLoop(Value* ptr, Loop* loop);
+  bool isMemoryLocationLoadedInLoop(Value* ptr, Loop* loop, Instruction* excludeInst = nullptr);
+  bool isPureFunction(Function* calledFunc);
 };
 
 } // namespace sysy

src/include/midend/Pass/Optimize/GVN.h

@@ -0,0 +1,87 @@
+#pragma once
+
+#include "Pass.h"
+#include "IR.h"
+#include "Dom.h"
+#include "SideEffectAnalysis.h"
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+#include <string>
+#include <sstream>
+
+namespace sysy {
+
+// GVN优化遍的核心逻辑封装类
+class GVNContext {
+public:
+    // 运行GVN优化的主要方法
+    void run(Function* func, AnalysisManager* AM, bool& changed);
+
+private:
+    // 新的值编号系统
+    std::unordered_map<Value*, unsigned> valueToNumber;      // Value -> 值编号
+    std::unordered_map<unsigned, Value*> numberToValue;      // 值编号 -> 代表值
+    std::unordered_map<std::string, unsigned> expressionToNumber; // 表达式 -> 值编号
+    unsigned nextValueNumber = 1;
+    
+    // 已访问的基本块集合
+    std::unordered_set<BasicBlock*> visited;
+    
+    // 逆后序遍历的基本块列表
+    std::vector<BasicBlock*> rpoBlocks;
+    
+    // 需要删除的指令集合
+    std::unordered_set<Instruction*> needRemove;
+    
+    // 分析结果
+    DominatorTree* domTree = nullptr;
+    SideEffectAnalysisResult* sideEffectAnalysis = nullptr;
+    
+    // 计算逆后序遍历
+    void computeRPO(Function* func);
+    void dfs(BasicBlock* bb);
+    
+    // 新的值编号方法
+    unsigned getValueNumber(Value* value);
+    unsigned assignValueNumber(Value* value);
+    
+    // 基本块处理
+    void processBasicBlock(BasicBlock* bb, bool& changed);
+    
+    // 指令处理
+    bool processInstruction(Instruction* inst);
+    
+    // 表达式构建和查找
+    std::string buildExpressionKey(Instruction* inst);
+    Value* findExistingValue(const std::string& exprKey, Instruction* inst);
+    
+    // 支配关系和安全性检查
+    bool dominates(Instruction* a, Instruction* b);
+    bool isMemorySafe(LoadInst* earlierLoad, LoadInst* laterLoad);
+    
+    // 清理方法
+    void eliminateRedundantInstructions(bool& changed);
+    void invalidateMemoryValues(StoreInst* store);
+};
+
+// GVN优化遍类
+class GVN : public OptimizationPass {
+public:
+    // 静态成员，作为该遍的唯一ID
+    static void* ID;
+    
+    GVN() : OptimizationPass("GVN", Granularity::Function) {}
+    
+    // 在函数上运行优化
+    bool runOnFunction(Function* func, AnalysisManager& AM) override;
+    
+    // 返回该遍的唯一ID
+    void* getPassID() const override { return ID; }
+    
+    // 声明分析依赖
+    void getAnalysisUsage(std::set<void*>& analysisDependencies, 
+                         std::set<void*>& analysisInvalidations) const override;
+};
+
+} // namespace sysy

src/include/midend/Pass/Optimize/InductionVariableElimination.h

@@ -0,0 +1,252 @@
+#pragma once
+
+#include "Pass.h"
+#include "IR.h"
+#include "LoopCharacteristics.h"
+#include "Loop.h"
+#include "Dom.h"
+#include "SideEffectAnalysis.h"
+#include "AliasAnalysis.h"
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+#include <memory>
+
+namespace sysy {
+
+// 前向声明
+class LoopCharacteristicsResult;
+class LoopAnalysisResult;
+
+/**
+ * @brief 死归纳变量信息
+ * 记录一个可以被消除的归纳变量
+ */
+struct DeadInductionVariable {
+  PhiInst* phiInst;                    // phi 指令
+  std::vector<Instruction*> relatedInsts; // 相关的递增/递减指令
+  Loop* containingLoop;                // 所在循环
+  bool canEliminate;                   // 是否可以安全消除
+  
+  DeadInductionVariable(PhiInst* phi, Loop* loop) 
+    : phiInst(phi), containingLoop(loop), canEliminate(false) {}
+};
+
+/**
+ * @brief 归纳变量消除上下文类
+ * 封装归纳变量消除优化的核心逻辑和状态
+ */
+class InductionVariableEliminationContext {
+public:
+  InductionVariableEliminationContext() {}
+  
+  /**
+   * 运行归纳变量消除优化
+   * @param F 目标函数
+   * @param AM 分析管理器
+   * @return 是否修改了IR
+   */
+  bool run(Function* F, AnalysisManager& AM);
+
+private:
+  // 分析结果缓存
+  LoopAnalysisResult* loopAnalysis = nullptr;
+  LoopCharacteristicsResult* loopCharacteristics = nullptr;
+  DominatorTree* dominatorTree = nullptr;
+  SideEffectAnalysisResult* sideEffectAnalysis = nullptr;
+  AliasAnalysisResult* aliasAnalysis = nullptr;
+  
+  // 死归纳变量存储
+  std::vector<std::unique_ptr<DeadInductionVariable>> deadIVs;
+  std::unordered_map<Loop*, std::vector<DeadInductionVariable*>> loopToDeadIVs;
+  
+  // ========== 核心分析和优化阶段 ==========
+  
+  /**
+   * 阶段1：识别死归纳变量
+   * 找出没有被有效使用的归纳变量
+   */
+  void identifyDeadInductionVariables(Function* F);
+  
+  /**
+   * 阶段2：分析消除的安全性
+   * 确保消除操作不会破坏程序语义
+   */
+  void analyzeSafetyForElimination();
+  
+  /**
+   * 阶段3：执行归纳变量消除
+   * 删除死归纳变量及其相关指令
+   */
+  bool performInductionVariableElimination();
+  
+  // ========== 辅助方法 ==========
+  
+  /**
+   * 检查归纳变量是否为死归纳变量
+   * @param iv 归纳变量信息
+   * @param loop 所在循环
+   * @return 如果是死归纳变量返回相关信息，否则返回nullptr
+   */
+  std::unique_ptr<DeadInductionVariable> 
+  isDeadInductionVariable(const InductionVarInfo* iv, Loop* loop);
+  
+  /**
+   * 递归分析phi指令及其使用链是否都是死代码
+   * @param phiInst phi指令
+   * @param loop 所在循环
+   * @return phi指令是否可以安全删除
+   */
+  bool isPhiInstructionDeadRecursively(PhiInst* phiInst, Loop* loop);
+  
+  /**
+   * 递归分析指令的使用链是否都是死代码
+   * @param inst 要分析的指令
+   * @param loop 所在循环
+   * @param visited 已访问的指令集合（避免无限递归）
+   * @param currentPath 当前递归路径（检测循环依赖）
+   * @return 指令的使用链是否都是死代码
+   */
+  bool isInstructionUseChainDeadRecursively(Instruction* inst, Loop* loop, 
+                                           std::set<Instruction*>& visited, 
+                                           std::set<Instruction*>& currentPath);
+  
+  /**
+   * 检查循环是否有副作用
+   * @param loop 要检查的循环
+   * @return 循环是否有副作用
+   */
+  bool loopHasSideEffects(Loop* loop);
+  
+  /**
+   * 检查指令是否被用于循环退出条件
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @return 是否被用于循环退出条件
+   */
+  bool isUsedInLoopExitCondition(Instruction* inst, Loop* loop);
+  
+  /**
+   * 检查指令的结果是否未被有效使用
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @return 指令结果是否未被有效使用
+   */
+  bool isInstructionResultUnused(Instruction* inst, Loop* loop);
+  
+  /**
+   * 检查store指令是否存储到死地址（利用别名分析）
+   * @param store store指令
+   * @param loop 所在循环  
+   * @return 是否存储到死地址
+   */
+  bool isStoreToDeadLocation(StoreInst* store, Loop* loop);
+  
+  /**
+   * 检查指令是否为死代码或只在循环内部使用
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @return 是否为死代码或只在循环内部使用
+   */
+  bool isInstructionDeadOrInternalOnly(Instruction* inst, Loop* loop);
+  
+  /**
+   * 检查指令是否有效地为死代码（带递归深度限制）
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @param maxDepth 最大递归深度
+   * @return 指令是否有效地为死代码
+   */
+  bool isInstructionEffectivelyDead(Instruction* inst, Loop* loop, int maxDepth);
+  
+  /**
+   * 检查store指令是否有后续的load操作
+   * @param store store指令
+   * @param loop 所在循环
+   * @return 是否有后续的load操作
+   */
+  bool hasSubsequentLoad(StoreInst* store, Loop* loop);
+  
+  /**
+   * 检查指令是否在循环外有使用
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @return 是否在循环外有使用
+   */
+  bool hasUsageOutsideLoop(Instruction* inst, Loop* loop);
+  
+  /**
+   * 检查store指令是否在循环外有后续的load操作
+   * @param store store指令
+   * @param loop 所在循环
+   * @return 是否在循环外有后续的load操作
+   */
+  bool hasSubsequentLoadOutsideLoop(StoreInst* store, Loop* loop);
+  
+  /**
+   * 递归检查基本块子树中是否有对指定位置的load操作
+   * @param bb 基本块
+   * @param ptr 指针
+   * @param visited 已访问的基本块集合
+   * @return 是否有load操作
+   */
+  bool hasLoadInSubtree(BasicBlock* bb, Value* ptr, std::set<BasicBlock*>& visited);
+  
+  /**
+   * 收集与归纳变量相关的所有指令
+   * @param phiInst phi指令
+   * @param loop 所在循环
+   * @return 相关指令列表
+   */
+  std::vector<Instruction*> collectRelatedInstructions(PhiInst* phiInst, Loop* loop);
+  
+  /**
+   * 检查消除归纳变量的安全性
+   * @param deadIV 死归纳变量
+   * @return 是否可以安全消除
+   */
+  bool isSafeToEliminate(const DeadInductionVariable* deadIV);
+  
+  /**
+   * 消除单个死归纳变量
+   * @param deadIV 死归纳变量
+   * @return 是否成功消除
+   */
+  bool eliminateDeadInductionVariable(DeadInductionVariable* deadIV);
+  
+  /**
+   * 打印调试信息
+   */
+  void printDebugInfo();
+};
+
+/**
+ * @brief 归纳变量消除优化遍
+ * 消除循环中无用的归纳变量，减少寄存器压力
+ */
+class InductionVariableElimination : public OptimizationPass {
+public:
+  // 唯一的 Pass ID
+  static void *ID;
+  
+  InductionVariableElimination() 
+    : OptimizationPass("InductionVariableElimination", Granularity::Function) {}
+  
+  /**
+   * 在函数上运行归纳变量消除优化
+   * @param F 目标函数
+   * @param AM 分析管理器
+   * @return 是否修改了IR
+   */
+  bool runOnFunction(Function* F, AnalysisManager& AM) override;
+  
+  /**
+   * 声明分析依赖和失效信息
+   */
+  void getAnalysisUsage(std::set<void*>& analysisDependencies, 
+                       std::set<void*>& analysisInvalidations) const override;
+  
+  void* getPassID() const override { return &ID; }
+};
+
+} // namespace sysy

src/include/midend/Pass/Optimize/LoopStrengthReduction.h

@@ -0,0 +1,240 @@
+#pragma once
+
+#include "Pass.h"
+#include "IR.h"
+#include "LoopCharacteristics.h"
+#include "Loop.h"
+#include "Dom.h"
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+#include <memory>
+
+namespace sysy {
+
+// 前向声明
+class LoopCharacteristicsResult;
+class LoopAnalysisResult;
+
+/**
+ * @brief 强度削弱候选项信息
+ * 记录一个可以进行强度削弱的表达式信息
+ */
+struct StrengthReductionCandidate {
+  enum OpType {
+    MULTIPLY,    // 乘法: iv * const
+    DIVIDE,      // 除法: iv / 2^n (转换为右移)
+    DIVIDE_CONST, // 除法: iv / const (使用mulh指令优化)
+    REMAINDER    // 取模: iv % 2^n (转换为位与)
+  };
+  
+  enum DivisionStrategy {
+    SIMPLE_SHIFT,     // 简单右移（仅适用于无符号或非负数）
+    SIGNED_CORRECTION, // 有符号除法修正: (x + (x >> 31) & mask) >> k
+    MULH_OPTIMIZATION  // 使用mulh指令优化任意常数除法
+  };
+  
+  Instruction* originalInst;      // 原始指令 (如 i*4, i/8, i%16)
+  Value* inductionVar;            // 归纳变量 (如 i)
+  OpType operationType;           // 操作类型
+  DivisionStrategy divStrategy;   // 除法策略（仅用于除法）
+  int multiplier;                 // 乘数/除数/模数 (如 4, 8, 16)
+  int shiftAmount;                // 位移量 (对于2的幂)
+  int offset;                     // 偏移量 (如常数项)
+  BasicBlock* containingBlock;    // 所在基本块
+  Loop* containingLoop;           // 所在循环
+  bool hasNegativeValues;         // 归纳变量是否可能为负数
+  
+  // 强度削弱后的新变量
+  PhiInst* newPhi = nullptr;      // 新的 phi 指令
+  Value* newInductionVar = nullptr; // 新的归纳变量
+  
+  StrengthReductionCandidate(Instruction* inst, Value* iv, OpType opType, int value, int off, 
+                           BasicBlock* bb, Loop* loop)
+    : originalInst(inst), inductionVar(iv), operationType(opType), 
+      divStrategy(SIMPLE_SHIFT), multiplier(value), offset(off), 
+      containingBlock(bb), containingLoop(loop), hasNegativeValues(false) {
+    
+    // 计算位移量（用于除法和取模的强度削弱）
+    if (opType == DIVIDE || opType == REMAINDER) {
+      shiftAmount = 0;
+      int temp = value;
+      while (temp > 1) {
+        temp >>= 1;
+        shiftAmount++;
+      }
+    } else {
+      shiftAmount = 0;
+    }
+  }
+};
+
+/**
+ * @brief 强度削弱上下文类
+ * 封装强度削弱优化的核心逻辑和状态
+ */
+class StrengthReductionContext {
+public:
+  StrengthReductionContext(IRBuilder* builder) : builder(builder) {}
+  
+  /**
+   * 运行强度削弱优化
+   * @param F 目标函数
+   * @param AM 分析管理器
+   * @return 是否修改了IR
+   */
+  bool run(Function* F, AnalysisManager& AM);
+
+private:
+  IRBuilder* builder;
+  
+  // 分析结果缓存
+  LoopAnalysisResult* loopAnalysis = nullptr;
+  LoopCharacteristicsResult* loopCharacteristics = nullptr;
+  DominatorTree* dominatorTree = nullptr;
+  
+  // 候选项存储
+  std::vector<std::unique_ptr<StrengthReductionCandidate>> candidates;
+  std::unordered_map<Loop*, std::vector<StrengthReductionCandidate*>> loopToCandidates;
+  
+  // ========== 核心分析和优化阶段 ==========
+  
+  /**
+   * 阶段1：识别强度削弱候选项
+   * 扫描所有循环中的乘法指令，找出可以优化的模式
+   */
+  void identifyStrengthReductionCandidates(Function* F);
+  
+  /**
+   * 阶段2：分析候选项的优化潜力
+   * 评估每个候选项的收益，过滤掉不值得优化的情况
+   */
+  void analyzeOptimizationPotential();
+  
+  /**
+   * 阶段3：执行强度削弱变换
+   * 对选中的候选项执行实际的强度削弱优化
+   */
+  bool performStrengthReduction();
+  
+  // ========== 辅助分析函数 ==========
+  
+  /**
+   * 分析归纳变量是否可能取负值
+   * @param ivInfo 归纳变量信息
+   * @param loop 所属循环
+   * @return 如果可能为负数返回true
+   */
+  bool analyzeInductionVariableRange(const InductionVarInfo* ivInfo, Loop* loop) const;
+  
+  /**
+   * 计算用于除法优化的魔数和移位量
+   * @param divisor 除数
+   * @return {魔数, 移位量}
+   */
+  std::pair<int, int> computeMulhMagicNumbers(int divisor) const;
+  
+  /**
+   * 生成除法替换代码
+   * @param candidate 优化候选项
+   * @param builder IR构建器
+   * @return 替换值
+   */
+  Value* generateDivisionReplacement(StrengthReductionCandidate* candidate, IRBuilder* builder) const;
+  
+  /**
+   * 生成任意常数除法替换代码
+   * @param candidate 优化候选项
+   * @param builder IR构建器
+   * @return 替换值
+   */
+  Value* generateConstantDivisionReplacement(StrengthReductionCandidate* candidate, IRBuilder* builder) const;
+  
+  /**
+   * 检查指令是否为强度削弱候选项
+   * @param inst 要检查的指令
+   * @param loop 所在循环
+   * @return 如果是候选项返回候选项信息，否则返回nullptr
+   */
+  std::unique_ptr<StrengthReductionCandidate> 
+  isStrengthReductionCandidate(Instruction* inst, Loop* loop);
+  
+  /**
+   * 检查值是否为循环的归纳变量
+   * @param val 要检查的值
+   * @param loop 循环
+   * @param characteristics 循环特征信息
+   * @return 如果是归纳变量返回归纳变量信息，否则返回nullptr
+   */
+  const InductionVarInfo* 
+  getInductionVarInfo(Value* val, Loop* loop, const LoopCharacteristics* characteristics);
+  
+  /**
+   * 为候选项创建新的归纳变量
+   * @param candidate 候选项
+   * @return 是否成功创建
+   */
+  bool createNewInductionVariable(StrengthReductionCandidate* candidate);
+  
+  /**
+   * 替换原始指令的所有使用
+   * @param candidate 候选项
+   * @return 是否成功替换
+   */
+  bool replaceOriginalInstruction(StrengthReductionCandidate* candidate);
+  
+  /**
+   * 估算优化收益
+   * 计算强度削弱后的性能提升
+   * @param candidate 候选项
+   * @return 估算的收益分数
+   */
+  double estimateOptimizationBenefit(const StrengthReductionCandidate* candidate);
+  
+  /**
+   * 检查优化的合法性
+   * @param candidate 候选项
+   * @return 是否可以安全地进行优化
+   */
+  bool isOptimizationLegal(const StrengthReductionCandidate* candidate);
+  
+  /**
+   * 打印调试信息
+   */
+  void printDebugInfo();
+};
+
+/**
+ * @brief 循环强度削弱优化遍
+ * 将循环中的乘法运算转换为更高效的加法运算
+ */
+class LoopStrengthReduction : public OptimizationPass {
+public:
+  // 唯一的 Pass ID
+  static void *ID;
+  
+  LoopStrengthReduction(IRBuilder* builder) 
+    : OptimizationPass("LoopStrengthReduction", Granularity::Function), 
+      builder(builder) {}
+  
+  /**
+   * 在函数上运行强度削弱优化
+   * @param F 目标函数
+   * @param AM 分析管理器
+   * @return 是否修改了IR
+   */
+  bool runOnFunction(Function* F, AnalysisManager& AM) override;
+  
+  /**
+   * 声明分析依赖和失效信息
+   */
+  void getAnalysisUsage(std::set<void*>& analysisDependencies, 
+                       std::set<void*>& analysisInvalidations) const override;
+  
+  void* getPassID() const override { return &ID; }
+
+private:
+  IRBuilder* builder;
+};
+
+} // namespace sysy

src/midend/CMakeLists.txt

@@ -15,10 +15,13 @@ add_library(midend_lib STATIC
     Pass/Optimize/DCE.cpp
     Pass/Optimize/Mem2Reg.cpp
     Pass/Optimize/Reg2Mem.cpp
+    Pass/Optimize/GVN.cpp
     Pass/Optimize/SysYIRCFGOpt.cpp
     Pass/Optimize/SCCP.cpp
     Pass/Optimize/LoopNormalization.cpp
     Pass/Optimize/LICM.cpp
+    Pass/Optimize/LoopStrengthReduction.cpp
+    Pass/Optimize/InductionVariableElimination.cpp
     Pass/Optimize/BuildCFG.cpp
     Pass/Optimize/LargeArrayToGlobal.cpp
 )

src/midend/IR.cpp

@@ -779,7 +779,29 @@ void BinaryInst::print(std::ostream &os) const {
     printOperand(os, getRhs());
     os << "\n    ";
     printVarName(os, this) << " = zext i1 %" << tmpName << " to i32";
-  } else {
+  } else if(kind == kMulh){
+    // 模拟高位乘法：先扩展为i64，乘法，右移32位，截断为i32
+    static int mulhCount = 0;
+    mulhCount++;
+    std::string lhsName = getLhs()->getName();
+    std::string rhsName = getRhs()->getName();
+    std::string tmpLhs = "tmp_mulh_lhs_" + std::to_string(mulhCount) + "_" + lhsName;
+    std::string tmpRhs = "tmp_mulh_rhs_" + std::to_string(mulhCount) +  rhsName;
+    std::string tmpMul = "tmp_mulh_mul_" + std::to_string(mulhCount) + getName();
+    std::string tmpHigh = "tmp_mulh_high_" + std::to_string(mulhCount) + getName();
+    // printVarName(os, this) << " = "; // 输出最终变量名
+
+    // os << "; mulh emulation\n    ";
+    os << "%" << tmpLhs << " = sext i32 ";
+    printOperand(os, getLhs());
+    os << " to i64\n    ";
+    os << "%" << tmpRhs << " = sext i32 ";
+    printOperand(os, getRhs());
+    os << " to i64\n    ";
+    os << "%" << tmpMul << " = mul i64 %" << tmpLhs << ", %" << tmpRhs << "\n    ";
+    os << "%" << tmpHigh << " = ashr i64 %" << tmpMul << ", 32\n    ";
+    printVarName(os, this) << " = trunc i64 %" << tmpHigh << " to i32";
+  }else {
     // 算术和逻辑指令
     printVarName(os, this) << " = ";
     os << getKindString() << " " << *getType() << " ";
@@ -825,7 +847,7 @@ void CondBrInst::print(std::ostream &os) const {
   
   os << "%tmp_cond_" << condName << "_" << uniqueSuffix << " = icmp ne i32 ";
   printOperand(os, condition);
-  os << ", 0\n  br i1 %tmp_cond_" << condName << "_" << uniqueSuffix;
+  os << ", 0\n    br i1 %tmp_cond_" << condName << "_" << uniqueSuffix;
   
   os << ", label %";
   printBlockName(os, getThenBlock());
@@ -864,7 +886,7 @@ void MemsetInst::print(std::ostream &os) const {
   // This is done at print time to avoid modifying the IR structure
   os << "%tmp_bitcast_" << ptr->getName() << " = bitcast " << *ptr->getType() << " ";
   printOperand(os, ptr);
-  os << " to i8*\n  ";
+  os << " to i8*\n    ";
   
   // Now call memset with the bitcast result
   os << "call void @llvm.memset.p0i8.i32(i8* %tmp_bitcast_" << ptr->getName() << ", i8 ";

src/midend/Pass/Analysis/LoopCharacteristics.cpp

@@ -80,8 +80,8 @@ void LoopCharacteristicsResult::print() const {
     std::cout << std::endl;
     
     // 归纳变量
-    if (!chars->basicInductionVars.empty()) {
-      std::cout << "  Basic Induction Vars: " << chars->basicInductionVars.size() << std::endl;
+    if (!chars->InductionVars.empty()) {
+      std::cout << "  Induction Vars: " << chars->InductionVars.size() << std::endl;
     }
     
     // 循环不变量
@@ -282,28 +282,338 @@ void LoopCharacteristicsPass::analyzeBasicMemoryAccessPatterns(Loop* loop, LoopC
   }
 }
 
-void LoopCharacteristicsPass::identifyBasicInductionVariables(Loop* loop, LoopCharacteristics* characteristics) {
-  // 寻找基本归纳变量（简化版本）
-  BasicBlock* header = loop->getHeader();
+bool LoopCharacteristicsPass::isBasicInductionVariable(Value* val, Loop* loop) {
+  // 简化的基础归纳变量检测
+  auto* phiInst = dynamic_cast<PhiInst*>(val);
+  if (!phiInst) return false;
   
-  // 遍历循环头的phi指令，寻找基本归纳变量模式
-  for (auto& inst : header->getInstructions()) {
-    auto* phiInst = dynamic_cast<PhiInst*>(inst.get());
-    if (!phiInst) continue;
-    
-    // 检查phi指令是否符合基本归纳变量模式
-    if (isBasicInductionVariable(phiInst, loop)) {
-      characteristics->basicInductionVars.push_back(phiInst);
-      characteristics->inductionSteps[phiInst] = 1; // 简化：默认步长为1
-      
-      if (DEBUG)
-        std::cout << "    Found basic induction variable: " << phiInst->getName() << std::endl;
+  // 检查phi指令是否在循环头
+  if (phiInst->getParent() != loop->getHeader()) return false;
+  
+  // 检查是否有来自循环内的更新
+  for (auto& [incomingBB, incomingVal] : phiInst->getIncomingValues()) {
+    if (loop->contains(incomingBB)) {
+      return true; // 简化：有来自循环内的值就认为是基础归纳变量
     }
   }
+  
+  return false;
+}
+
+
+void LoopCharacteristicsPass::identifyBasicInductionVariables(
+    Loop* loop, LoopCharacteristics* characteristics) {
+  BasicBlock* header = loop->getHeader();
+  std::vector<std::unique_ptr<InductionVarInfo>> ivs;
+
+  if (DEBUG) {
+    std::cout << "    === Identifying Induction Variables for Loop: " << loop->getName() << " ===" << std::endl;
+    std::cout << "    Loop header: " << header->getName() << std::endl;
+    std::cout << "    Loop blocks: ";
+    for (auto* bb : loop->getBlocks()) {
+      std::cout << bb->getName() << " ";
+    }
+    std::cout << std::endl;
+  }
+
+  // 1. 识别所有BIV
+  for (auto& inst : header->getInstructions()) {
+    auto* phi = dynamic_cast<PhiInst*>(inst.get());
+    if (!phi) continue;
+    if (isBasicInductionVariable(phi, loop)) {
+      ivs.push_back(InductionVarInfo::createBasicBIV(phi, Instruction::Kind::kPhi, phi));
+      if (DEBUG) {
+        std::cout << "    [BIV] Found basic induction variable: " << phi->getName() << std::endl;
+        std::cout << "          Incoming values: ";
+        for (auto& [incomingBB, incomingVal] : phi->getIncomingValues()) {
+          std::cout << "{" << incomingBB->getName() << ": " << incomingVal->getName() << "} ";
+        }
+        std::cout << std::endl;
+      }
+    }
+  }
+
+  if (DEBUG) {
+    std::cout << "    Found " << ivs.size() << " basic induction variables" << std::endl;
+  }
+
+  // 2. 递归识别所有派生DIV
+  std::set<Value*> visited;
+  size_t initialSize = ivs.size();
+  
+  // 保存初始的BIV列表，避免在遍历过程中修改向量导致迭代器失效
+  std::vector<InductionVarInfo*> bivList;
+  for (size_t i = 0; i < initialSize; ++i) {
+    if (ivs[i] && ivs[i]->ivkind == IVKind::kBasic) {
+      bivList.push_back(ivs[i].get());
+    }
+  }
+  
+  for (auto* biv : bivList) {
+    if (DEBUG) {
+      if (biv && biv->div) {
+        std::cout << "    Searching for derived IVs from BIV: " << biv->div->getName() << std::endl;
+      } else {
+        std::cout << "    ERROR: Invalid BIV pointer or div field is null" << std::endl;
+        continue;
+      }
+    }
+    findDerivedInductionVars(biv->div, biv->base, loop, ivs, visited);
+  }
+
+  if (DEBUG) {
+    size_t derivedCount = ivs.size() - initialSize;
+    std::cout << "    Found " << derivedCount << " derived induction variables" << std::endl;
+    
+    // 打印所有归纳变量的详细信息
+    std::cout << "    === Final Induction Variables Summary ===" << std::endl;
+    for (size_t i = 0; i < ivs.size(); ++i) {
+      const auto& iv = ivs[i];
+      std::cout << "    [" << i << "] " << iv->div->getName() 
+                << " (kind: " << (iv->ivkind == IVKind::kBasic ? "Basic" : 
+                               iv->ivkind == IVKind::kLinear ? "Linear" : "Complex") << ")" << std::endl;
+      std::cout << "        Operation: " << static_cast<int>(iv->Instkind) << std::endl;
+      if (iv->base) {
+        std::cout << "        Base: " << iv->base->getName() << std::endl;
+      }
+      if (iv->Multibase.first || iv->Multibase.second) {
+        std::cout << "        Multi-base: ";
+        if (iv->Multibase.first) std::cout << iv->Multibase.first->getName() << " ";
+        if (iv->Multibase.second) std::cout << iv->Multibase.second->getName() << " ";
+        std::cout << std::endl;
+      }
+      std::cout << "        Factor: " << iv->factor << ", Offset: " << iv->offset << std::endl;
+      std::cout << "        Valid: " << (iv->valid ? "Yes" : "No") << std::endl;
+    }
+    std::cout << "    =============================================" << std::endl;
+  }
+
+  characteristics->InductionVars = std::move(ivs);
+}
+
+
+struct LinearExpr {
+  // 表达为: a * base1 + b * base2 + offset
+  Value* base1 = nullptr;
+  Value* base2 = nullptr;
+  int factor1 = 0;
+  int factor2 = 0;
+  int offset = 0;
+  bool valid = false;
+  bool isSimple = false; // 仅一个BIV时true
+};
+
+static LinearExpr analyzeLinearExpr(Value* val, Loop* loop, std::vector<std::unique_ptr<InductionVarInfo>>& ivs) {
+  // 递归归约val为线性表达式
+  // 只支持单/双BIV线性组合
+  // 见下方详细实现
+  // ----------
+  if (DEBUG >= 2) {  // 更详细的调试级别
+    if (auto* inst = dynamic_cast<Instruction*>(val)) {
+      std::cout << "        Analyzing linear expression for: " << val->getName() 
+                << " (kind: " << static_cast<int>(inst->getKind()) << ")" << std::endl;
+    } else {
+      std::cout << "        Analyzing linear expression for value: " << val->getName() << std::endl;
+    }
+  }
+  
+  // 基本变量：常数
+  if (auto* cint = dynamic_cast<ConstantInteger*>(val)) {
+    if (DEBUG >= 2) {
+      std::cout << "        -> Constant: " << cint->getInt() << std::endl;
+    }
+    return {nullptr, nullptr, 0, 0, cint->getInt(), true, false};
+  }
+  
+  // 基本变量：BIV或派生IV
+  for (auto& iv : ivs) {
+    if (iv->div == val) {
+      if (iv->ivkind == IVKind::kBasic ||
+          iv->ivkind == IVKind::kLinear) {
+        if (DEBUG >= 2) {
+          std::cout << "        -> Found " << (iv->ivkind == IVKind::kBasic ? "Basic" : "Linear") 
+                    << " IV with base: " << (iv->base ? iv->base->getName() : "null") 
+                    << ", factor: " << iv->factor << ", offset: " << iv->offset << std::endl;
+        }
+        return {iv->base, nullptr, iv->factor, 0, iv->offset, true, true};
+      }
+      // 复杂归纳变量
+      if (iv->ivkind == IVKind::kCmplx) {
+        if (DEBUG >= 2) {
+          std::cout << "        -> Found Complex IV with multi-base" << std::endl;
+        }
+        return {iv->Multibase.first, iv->Multibase.second, 1, 1, 0, true, false};
+      }
+    }
+  }
+  
+  // 一元负号
+  if (auto* inst = dynamic_cast<Instruction*>(val)) {
+    auto kind = inst->getKind();
+    if (kind == Instruction::Kind::kNeg) {
+      if (DEBUG >= 2) {
+        std::cout << "        -> Analyzing negation" << std::endl;
+      }
+      auto expr = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
+      if (!expr.valid) return expr;
+      expr.factor1 = -expr.factor1;
+      expr.factor2 = -expr.factor2;
+      expr.offset = -expr.offset;
+      expr.isSimple = (expr.base2 == nullptr);
+      if (DEBUG >= 2) {
+        std::cout << "        -> Negation result: valid=" << expr.valid << ", simple=" << expr.isSimple << std::endl;
+      }
+      return expr;
+    }
+    
+    // 二元加减乘
+    if (kind == Instruction::Kind::kAdd || kind == Instruction::Kind::kSub) {
+      if (DEBUG >= 2) {
+        std::cout << "        -> Analyzing " << (kind == Instruction::Kind::kAdd ? "addition" : "subtraction") << std::endl;
+      }
+      auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
+      auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
+      if (!expr0.valid || !expr1.valid) {
+        if (DEBUG >= 2) {
+          std::cout << "        -> Failed: operand not linear (expr0.valid=" << expr0.valid << ", expr1.valid=" << expr1.valid << ")" << std::endl;
+        }
+        return {nullptr, nullptr, 0, 0, 0, false, false};
+      }
+      
+      // 合并：若BIV相同或有一个是常数
+      // 单BIV+常数
+      if (expr0.base1 && !expr1.base1 && !expr1.base2) {
+        int sign = (kind == Instruction::Kind::kAdd ? 1 : -1);
+        if (DEBUG >= 2) {
+          std::cout << "        -> Single BIV + constant pattern" << std::endl;
+        }
+        return {expr0.base1, nullptr, expr0.factor1, 0, expr0.offset + sign * expr1.offset, true, expr0.isSimple};
+      }
+      if (!expr0.base1 && !expr0.base2 && expr1.base1) {
+        int sign = (kind == Instruction::Kind::kAdd ? 1 : -1);
+        int f = sign * expr1.factor1;
+        int off = expr0.offset + sign * expr1.offset;
+        if (DEBUG >= 2) {
+          std::cout << "        -> Constant + single BIV pattern" << std::endl;
+        }
+        return {expr1.base1, nullptr, f, 0, off, true, expr1.isSimple};
+      }
+      
+      // 双BIV线性组合
+      if (expr0.base1 && expr1.base1 && expr0.base1 != expr1.base1 && !expr0.base2 && !expr1.base2) {
+        int sign = (kind == Instruction::Kind::kAdd ? 1 : -1);
+        Value* base1 = expr0.base1;
+        Value* base2 = expr1.base1;
+        int f1 = expr0.factor1;
+        int f2 = sign * expr1.factor1;
+        int off = expr0.offset + sign * expr1.offset;
+        if (DEBUG >= 2) {
+          std::cout << "        -> Double BIV linear combination" << std::endl;
+        }
+        return {base1, base2, f1, f2, off, true, false};
+      }
+      
+      // 同BIV合并
+      if (expr0.base1 && expr1.base1 && expr0.base1 == expr1.base1 && !expr0.base2 && !expr1.base2) {
+        int sign = (kind == Instruction::Kind::kAdd ? 1 : -1);
+        int f = expr0.factor1 + sign * expr1.factor1;
+        int off = expr0.offset + sign * expr1.offset;
+        if (DEBUG >= 2) {
+          std::cout << "        -> Same BIV combination" << std::endl;
+        }
+        return {expr0.base1, nullptr, f, 0, off, true, true};
+      }
+    }
+    
+    // 乘法：BIV*const 或 const*BIV
+    if (kind == Instruction::Kind::kMul) {
+      if (DEBUG >= 2) {
+        std::cout << "        -> Analyzing multiplication" << std::endl;
+      }
+      auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
+      auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
+      
+      // 只允许一侧为常数
+      if (expr0.base1 && !expr1.base1 && !expr1.base2 && expr1.offset) {
+        if (DEBUG >= 2) {
+          std::cout << "        -> BIV * constant pattern" << std::endl;
+        }
+        return {expr0.base1, nullptr, expr0.factor1 * expr1.offset, 0, expr0.offset * expr1.offset, true, true};
+      }
+      if (!expr0.base1 && !expr0.base2 && expr0.offset && expr1.base1) {
+        if (DEBUG >= 2) {
+          std::cout << "        -> Constant * BIV pattern" << std::endl;
+        }
+        return {expr1.base1, nullptr, expr1.factor1 * expr0.offset, 0, expr1.offset * expr0.offset, true, true};
+      }
+      // 双BIV乘法不支持
+      if (DEBUG >= 2) {
+        std::cout << "        -> Multiplication pattern not supported" << std::endl;
+      }
+    }
+    
+    // 除法：BIV/const（仅当const是2的幂时）
+    if (kind == Instruction::Kind::kDiv) {
+      if (DEBUG >= 2) {
+        std::cout << "        -> Analyzing division" << std::endl;
+      }
+      auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
+      auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
+      
+      // 只支持 BIV / 2^n 形式
+      if (expr0.base1 && !expr1.base1 && !expr1.base2 && expr1.offset > 0) {
+        // 检查是否为2的幂
+        int divisor = expr1.offset;
+        if ((divisor & (divisor - 1)) == 0) { // 2的幂检查
+          if (DEBUG >= 2) {
+            std::cout << "        -> BIV / power_of_2 pattern (divisor=" << divisor << ")" << std::endl;
+          }
+          // 对于除法，我们记录为特殊的归纳变量模式
+          // factor表示除数（用于后续强度削弱）
+          return {expr0.base1, nullptr, -divisor, 0, expr0.offset / divisor, true, true};
+        }
+      }
+      if (DEBUG >= 2) {
+        std::cout << "        -> Division pattern not supported (not power of 2)" << std::endl;
+      }
+    }
+    
+    // 取模：BIV % const（仅当const是2的幂时）
+    if (kind == Instruction::Kind::kRem) {
+      if (DEBUG >= 2) {
+        std::cout << "        -> Analyzing remainder" << std::endl;
+      }
+      auto expr0 = analyzeLinearExpr(inst->getOperand(0), loop, ivs);
+      auto expr1 = analyzeLinearExpr(inst->getOperand(1), loop, ivs);
+      
+      // 只支持 BIV % 2^n 形式
+      if (expr0.base1 && !expr1.base1 && !expr1.base2 && expr1.offset > 0) {
+        // 检查是否为2的幂
+        int modulus = expr1.offset;
+        if ((modulus & (modulus - 1)) == 0) { // 2的幂检查
+          if (DEBUG >= 2) {
+            std::cout << "        -> BIV % power_of_2 pattern (modulus=" << modulus << ")" << std::endl;
+          }
+          // 对于取模，我们记录为特殊的归纳变量模式
+          // 使用负的模数来区分取模和除法
+          return {expr0.base1, nullptr, -10000 - modulus, 0, 0, true, true}; // 特殊标记
+        }
+      }
+      if (DEBUG >= 2) {
+        std::cout << "        -> Remainder pattern not supported (not power of 2)" << std::endl;
+      }
+    }
+  }
+  
+  // 其它情况
+  if (DEBUG >= 2) {
+    std::cout << "        -> Other case: not linear" << std::endl;
+  }
+  return {nullptr, nullptr, 0, 0, 0, false, false};
 }
 
 void LoopCharacteristicsPass::identifyBasicLoopInvariants(Loop* loop, LoopCharacteristics* characteristics) {
-  // 经典推进法：反复遍历，直到收敛
+  // 经典推进法：反复遍历，直到收敛 TODO：优化
   bool changed;
   std::unordered_set<Value*> invariants = characteristics->loopInvariants; // 可能为空
 
@@ -334,7 +644,7 @@ void LoopCharacteristicsPass::identifyBasicLoopInvariants(Loop* loop, LoopCharac
 void LoopCharacteristicsPass::analyzeBasicLoopBounds(Loop* loop, LoopCharacteristics* characteristics) {
   // 简化的基础边界分析
   // 检查是否有静态可确定的循环次数（简化版本）
-  if (characteristics->isCountingLoop && !characteristics->basicInductionVars.empty()) {
+  if (characteristics->isCountingLoop && !characteristics->InductionVars.empty()) {
     // 简化：如果是计数循环且有基本归纳变量，尝试确定循环次数
     if (characteristics->instructionCount < 10) {
       characteristics->staticTripCount = 100; // 简化估计
@@ -373,56 +683,417 @@ void LoopCharacteristicsPass::evaluateBasicOptimizationOpportunities(Loop* loop,
 
 // ========== 辅助方法实现 ==========
 
-bool LoopCharacteristicsPass::isBasicInductionVariable(Value* val, Loop* loop) {
-  // 简化的基础归纳变量检测
-  auto* phiInst = dynamic_cast<PhiInst*>(val);
-  if (!phiInst) return false;
-  
-  // 检查phi指令是否在循环头
-  if (phiInst->getParent() != loop->getHeader()) return false;
-  
-  // 检查是否有来自循环内的更新
-  for (auto& [incomingBB, incomingVal] : phiInst->getIncomingValues()) {
-    if (loop->contains(incomingBB)) {
-      return true; // 简化：有来自循环内的值就认为是基础归纳变量
+// 递归识别DIV，支持线性与复杂归纳变量
+void LoopCharacteristicsPass::findDerivedInductionVars(
+    Value* root,
+    Value* base, // 只传单一BIV base
+    Loop* loop,
+    std::vector<std::unique_ptr<InductionVarInfo>>& ivs,
+    std::set<Value*>& visited)
+{
+  if (visited.count(root)) return;
+  visited.insert(root);
+
+  if (DEBUG) {
+    std::cout << "      Analyzing uses of: " << root->getName() << std::endl;
+  }
+
+  for (auto use : root->getUses()) {
+    auto user = use->getUser();
+    Instruction* inst = dynamic_cast<Instruction*>(user);
+    if (!inst) continue;
+    if (!loop->contains(inst->getParent())) {
+      if (DEBUG) {
+        std::cout << "      Skipping user outside loop: " << inst->getName() << std::endl;
+      }
+      continue;
+    }
+
+    if (DEBUG) {
+      std::cout << "      Checking instruction: " << inst->getName() 
+                << " (kind: " << static_cast<int>(inst->getKind()) << ")" << std::endl;
+    }
+
+    // 线性归约分析
+    auto expr = analyzeLinearExpr(inst, loop, ivs);
+
+    if (!expr.valid) {
+      if (DEBUG) {
+        std::cout << "      Linear expression analysis failed for: " << inst->getName() << std::endl;
+      }
+      // 复杂非线性归纳变量，作为kCmplx记录（假如你想追踪）
+      // 这里假设expr.base1、base2都有效才记录double
+      if (expr.base1 && expr.base2) {
+        if (DEBUG) {
+          std::cout << "      [DIV-COMPLEX] Creating complex derived IV: " << inst->getName() 
+                    << " with bases: " << expr.base1->getName() << ", " << expr.base2->getName() << std::endl;
+        }
+        ivs.push_back(InductionVarInfo::createDoubleDIV(inst, inst->getKind(), expr.base1, expr.base2, 0, expr.offset));
+      }
+      continue;
+    }
+
+    // 单BIV线性
+    if (expr.base1 && !expr.base2) {
+      // 检查这个指令是否已经是一个已知的IV（特别是BIV），避免重复创建
+      bool alreadyExists = false;
+      for (const auto& existingIV : ivs) {
+        if (existingIV->div == inst) {
+          alreadyExists = true;
+          if (DEBUG) {
+            std::cout << "      [DIV-SKIP] Instruction " << inst->getName() 
+                      << " already exists as IV, skipping creation" << std::endl;
+          }
+          break;
+        }
+      }
+      
+      if (!alreadyExists) {
+        if (DEBUG) {
+          std::cout << "      [DIV-LINEAR] Creating single-base derived IV: " << inst->getName() 
+                    << " with base: " << expr.base1->getName() 
+                    << ", factor: " << expr.factor1 
+                    << ", offset: " << expr.offset << std::endl;
+        }
+        ivs.push_back(InductionVarInfo::createSingleDIV(inst, inst->getKind(), expr.base1, expr.factor1, expr.offset));
+        findDerivedInductionVars(inst, expr.base1, loop, ivs, visited);
+      }
+    }
+    // 双BIV线性
+    else if (expr.base1 && expr.base2) {
+      if (DEBUG) {
+        std::cout << "      [DIV-COMPLEX] Creating double-base derived IV: " << inst->getName() 
+                  << " with bases: " << expr.base1->getName() << ", " << expr.base2->getName() 
+                  << ", offset: " << expr.offset << std::endl;
+      }
+      ivs.push_back(InductionVarInfo::createDoubleDIV(inst, inst->getKind(), expr.base1, expr.base2, 0, expr.offset));
+      // 双BIV情形一般不再递归下游
+    }
+  }
+
+  if (DEBUG) {
+    std::cout << "      Finished analyzing uses of: " << root->getName() << std::endl;
+  }
+}
+
+// 检查操作数是否都是不变量
+bool LoopCharacteristicsPass::isInvariantOperands(Instruction* inst, Loop* loop, const std::unordered_set<Value*>& invariants) {
+  for (size_t i = 0; i < inst->getNumOperands(); ++i) {
+    Value* op = inst->getOperand(i);
+    if (!isClassicLoopInvariant(op, loop, invariants) && !invariants.count(op)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+// 检查内存位置是否在循环中被修改
+bool LoopCharacteristicsPass::isMemoryLocationModifiedInLoop(Value* ptr, Loop* loop) {
+  // 遍历循环中的所有指令，检查是否有对该内存位置的写入
+  for (BasicBlock* bb : loop->getBlocks()) {
+    for (auto& inst : bb->getInstructions()) {
+      // 1. 检查直接的Store指令
+      if (auto* storeInst = dynamic_cast<StoreInst*>(inst.get())) {
+        Value* storeTar = storeInst->getPointer();
+        
+        // 使用别名分析检查是否可能别名
+        if (aliasAnalysis) {
+          auto aliasType = aliasAnalysis->queryAlias(ptr, storeTar);
+          if (aliasType != AliasType::NO_ALIAS) {
+            if (DEBUG) {
+              std::cout << "      Memory location " << ptr->getName() 
+                        << " may be modified by store to " << storeTar->getName() << std::endl;
+            }
+            return true;
+          }
+        } else {
+          // 如果没有别名分析，保守处理 - 只检查精确匹配
+          if (ptr == storeTar) {
+            return true;
+          }
+        }
+      }
+      
+      // 2. 检查函数调用是否可能修改该内存位置
+      else if (auto* callInst = dynamic_cast<CallInst*>(inst.get())) {
+        Function* calledFunc = callInst->getCallee();
+        
+        // 如果是纯函数，不会修改内存
+        if (isPureFunction(calledFunc)) {
+          continue;
+        }
+        
+        // 检查函数参数中是否有该内存位置的指针
+        for (size_t i = 1; i < callInst->getNumOperands(); ++i) { // 跳过函数指针
+          Value* arg = callInst->getOperand(i);
+          
+          // 检查参数是否是指针类型且可能指向该内存位置
+          if (auto* ptrType = dynamic_cast<PointerType*>(arg->getType())) {
+            // 使用别名分析检查
+            if (aliasAnalysis) {
+              auto aliasType = aliasAnalysis->queryAlias(ptr, arg);
+              if (aliasType != AliasType::NO_ALIAS) {
+                if (DEBUG) {
+                  std::cout << "      Memory location " << ptr->getName() 
+                            << " may be modified by function call " << calledFunc->getName()
+                            << " through parameter " << arg->getName() << std::endl;
+                }
+                return true;
+              }
+            } else {
+              // 没有别名分析，检查精确匹配
+              if (ptr == arg) {
+                if (DEBUG) {
+                  std::cout << "      Memory location " << ptr->getName() 
+                            << " may be modified by function call " << calledFunc->getName()
+                            << " (exact match)" << std::endl;
+                }
+                return true;
+              }
+            }
+          }
+        }
+      }
     }
   }
-  
   return false;
 }
 
-// 递归/推进式判定
+// 检查内存位置是否在循环中被读取
+bool LoopCharacteristicsPass::isMemoryLocationLoadedInLoop(Value* ptr, Loop* loop, Instruction* excludeInst) {
+  // 遍历循环中的所有Load指令，检查是否有对该内存位置的读取
+  for (BasicBlock* bb : loop->getBlocks()) {
+    for (auto& inst : bb->getInstructions()) {
+      if (inst.get() == excludeInst) continue; // 排除当前指令本身
+      
+      if (auto* loadInst = dynamic_cast<LoadInst*>(inst.get())) {
+        Value* loadSrc = loadInst->getPointer();
+        
+        // 使用别名分析检查是否可能别名
+        if (aliasAnalysis) {
+          auto aliasType = aliasAnalysis->queryAlias(ptr, loadSrc);
+          if (aliasType != AliasType::NO_ALIAS) {
+            return true;
+          }
+        } else {
+          // 如果没有别名分析，保守处理 - 只检查精确匹配
+          if (ptr == loadSrc) {
+            return true;
+          }
+        }
+      }
+    }
+  }
+  return false;
+}
+
+// 检查函数调用是否为纯函数
+bool LoopCharacteristicsPass::isPureFunction(Function* calledFunc) {
+  if (!calledFunc) return false;
+  
+  // 使用副作用分析检查函数是否为纯函数
+  if (sideEffectAnalysis && sideEffectAnalysis->isPureFunction(calledFunc)) {
+    return true;
+  }
+  
+  // 检查是否为内置纯函数（如数学函数）
+  std::string funcName = calledFunc->getName();
+  static const std::set<std::string> pureFunctions = {
+    "abs", "fabs", "sqrt", "sin", "cos", "tan", "exp", "log", "pow",
+    "floor", "ceil", "round", "min", "max"
+  };
+  
+  return pureFunctions.count(funcName) > 0;
+}
+
+// 递归/推进式判定 - 完善版本
 bool LoopCharacteristicsPass::isClassicLoopInvariant(Value* val, Loop* loop, const std::unordered_set<Value*>& invariants) {
+  if (DEBUG >= 2) {
+    std::cout << "    Checking loop invariant for: " << val->getName() << std::endl;
+  }
+  
   // 1. 常量
-  if (auto* constval = dynamic_cast<ConstantValue*>(val)) return true;
+  if (auto* constval = dynamic_cast<ConstantValue*>(val)) {
+    if (DEBUG >= 2) std::cout << "    -> Constant: YES" << std::endl;
+    return true;
+  }
 
   // 2. 参数（函数参数）通常不在任何BasicBlock内，直接判定为不变量
-  if (auto* arg = dynamic_cast<Argument*>(val)) return true;
+  // 在SSA形式下，参数不会被重新赋值
+  if (auto* arg = dynamic_cast<Argument*>(val)) {
+    if (DEBUG >= 2) std::cout << "    -> Function argument: YES" << std::endl;
+    return true;
+  }
 
   // 3. 指令且定义在循环外
   if (auto* inst = dynamic_cast<Instruction*>(val)) {
-    if (!loop->contains(inst->getParent()))
+    if (!loop->contains(inst->getParent())) {
+      if (DEBUG >= 2) std::cout << "    -> Defined outside loop: YES" << std::endl;
       return true;
-
-    // 4. 跳转 phi指令 副作用 不外提
-    if (inst->isTerminator() || inst->isPhi() || sideEffectAnalysis->hasSideEffect(inst))
-      return false;
-
-    // 5. 所有操作数都是不变量
-    for (size_t i = 0; i < inst->getNumOperands(); ++i) {
-      Value* op = inst->getOperand(i);
-      if (!isClassicLoopInvariant(op, loop, invariants) && !invariants.count(op))
-        return false;
     }
-    return true;
+
+    // 4. 跳转指令、phi指令不能外提
+    if (inst->isTerminator() || inst->isPhi()) {
+      if (DEBUG >= 2) std::cout << "    -> Terminator or PHI: NO" << std::endl;
+      return false;
+    }
+
+    // 5. 根据指令类型进行具体分析
+    switch (inst->getKind()) {
+      case Instruction::Kind::kStore: {
+        // Store指令：检查循环内是否有对该内存的load
+        auto* storeInst = dynamic_cast<StoreInst*>(inst);
+        Value* storePtr = storeInst->getPointer();
+        
+        // 首先检查操作数是否不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Store: operands not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        // 检查是否有对该内存位置的load
+        if (isMemoryLocationLoadedInLoop(storePtr, loop, inst)) {
+          if (DEBUG >= 2) std::cout << "    -> Store: memory location loaded in loop: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Store: safe to hoist: YES" << std::endl;
+        return true;
+      }
+      
+      case Instruction::Kind::kLoad: {
+        // Load指令：检查循环内是否有对该内存的store
+        auto* loadInst = dynamic_cast<LoadInst*>(inst);
+        Value* loadPtr = loadInst->getPointer();
+        
+        // 首先检查指针操作数是否不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Load: pointer not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        // 检查是否有对该内存位置的store
+        if (isMemoryLocationModifiedInLoop(loadPtr, loop)) {
+          if (DEBUG >= 2) std::cout << "    -> Load: memory location modified in loop: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Load: safe to hoist: YES" << std::endl;
+        return true;
+      }
+      
+      case Instruction::Kind::kCall: {
+        // Call指令：检查是否为纯函数且参数不变
+        auto* callInst = dynamic_cast<CallInst*>(inst);
+        Function* calledFunc = callInst->getCallee();
+        
+        // 检查是否为纯函数
+        if (!isPureFunction(calledFunc)) {
+          if (DEBUG >= 2) std::cout << "    -> Call: not pure function: NO" << std::endl;
+          return false;
+        }
+        
+        // 检查参数是否都不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Call: arguments not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Call: pure function with invariant args: YES" << std::endl;
+        return true;
+      }
+      
+      case Instruction::Kind::kGetElementPtr: {
+        // GEP指令：检查基址和索引是否都不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> GEP: base or indices not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> GEP: base and indices invariant: YES" << std::endl;
+        return true;
+      }
+      
+      // 一元运算指令
+      case Instruction::Kind::kNeg:
+      case Instruction::Kind::kNot:
+      case Instruction::Kind::kFNeg:
+      case Instruction::Kind::kFNot:
+      case Instruction::Kind::kFtoI:
+      case Instruction::Kind::kItoF:
+      case Instruction::Kind::kBitItoF:
+      case Instruction::Kind::kBitFtoI: {
+        // 检查操作数是否不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Unary op: operand not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Unary op: operand invariant: YES" << std::endl;
+        return true;
+      }
+      
+      // 二元运算指令
+      case Instruction::Kind::kAdd:
+      case Instruction::Kind::kSub:
+      case Instruction::Kind::kMul:
+      case Instruction::Kind::kDiv:
+      case Instruction::Kind::kRem:
+      case Instruction::Kind::kSll:
+      case Instruction::Kind::kSrl:
+      case Instruction::Kind::kSra:
+      case Instruction::Kind::kAnd:
+      case Instruction::Kind::kOr:
+      case Instruction::Kind::kFAdd:
+      case Instruction::Kind::kFSub:
+      case Instruction::Kind::kFMul:
+      case Instruction::Kind::kFDiv:
+      case Instruction::Kind::kICmpEQ:
+      case Instruction::Kind::kICmpNE:
+      case Instruction::Kind::kICmpLT:
+      case Instruction::Kind::kICmpGT:
+      case Instruction::Kind::kICmpLE:
+      case Instruction::Kind::kICmpGE:
+      case Instruction::Kind::kFCmpEQ:
+      case Instruction::Kind::kFCmpNE:
+      case Instruction::Kind::kFCmpLT:
+      case Instruction::Kind::kFCmpGT:
+      case Instruction::Kind::kFCmpLE:
+      case Instruction::Kind::kFCmpGE:
+      case Instruction::Kind::kMulh: {
+        // 检查所有操作数是否不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Binary op: operands not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Binary op: operands invariant: YES" << std::endl;
+        return true;
+      }
+      
+      default: {
+        // 其他指令：使用副作用分析
+        if (sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(inst)) {
+          if (DEBUG >= 2) std::cout << "    -> Other inst: has side effect: NO" << std::endl;
+          return false;
+        }
+        
+        // 检查操作数是否都不变
+        if (!isInvariantOperands(inst, loop, invariants)) {
+          if (DEBUG >= 2) std::cout << "    -> Other inst: operands not invariant: NO" << std::endl;
+          return false;
+        }
+        
+        if (DEBUG >= 2) std::cout << "    -> Other inst: no side effect, operands invariant: YES" << std::endl;
+        return true;
+      }
+    }
   }
+  
   // 其它情况
+  if (DEBUG >= 2) std::cout << "    -> Other value type: NO" << std::endl;
   return false;
 }
 
-bool LoopCharacteristicsPass::hasSimpleMemoryPattern(Loop* loop) {
-  // 检查是否有简单的内存访问模式
-  return true; // 暂时简化处理
-}
 
 } // namespace sysy

src/midend/Pass/Analysis/SideEffectAnalysis.cpp

@@ -26,10 +26,21 @@ const SideEffectInfo &SideEffectAnalysisResult::getInstructionSideEffect(Instruc
 }
 
 const SideEffectInfo &SideEffectAnalysisResult::getFunctionSideEffect(Function *func) const {
+  // 首先检查分析过的用户定义函数
   auto it = functionSideEffects.find(func);
   if (it != functionSideEffects.end()) {
     return it->second;
   }
+  
+  // 如果没有找到，检查是否为已知的库函数
+  if (func) {
+    std::string funcName = func->getName();
+    const SideEffectInfo *knownInfo = getKnownFunctionSideEffect(funcName);
+    if (knownInfo) {
+      return *knownInfo;
+    }
+  }
+  
   // 返回默认的无副作用信息
   static SideEffectInfo noEffect;
   return noEffect;

src/midend/Pass/Optimize/GVN.cpp

@@ -0,0 +1,492 @@
+#include "GVN.h"
+#include "Dom.h"
+#include "SysYIROptUtils.h"
+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <unordered_map>
+#include <unordered_set>
+
+extern int DEBUG;
+
+namespace sysy {
+
+// GVN 遍的静态 ID
+void *GVN::ID = (void *)&GVN::ID;
+
+// ======================================================================
+// GVN 类的实现
+// ======================================================================
+
+bool GVN::runOnFunction(Function *func, AnalysisManager &AM) {
+  if (func->getBasicBlocks().empty()) {
+    return false;
+  }
+
+  if (DEBUG) {
+    std::cout << "\n=== Running GVN on function: " << func->getName() << " ===" << std::endl;
+  }
+
+  bool changed = false;
+  GVNContext context;
+  context.run(func, &AM, changed);
+
+  if (DEBUG) {
+    if (changed) {
+      std::cout << "GVN: Function " << func->getName() << " was modified" << std::endl;
+    } else {
+      std::cout << "GVN: Function " << func->getName() << " was not modified" << std::endl;
+    }
+    std::cout << "=== GVN completed for function: " << func->getName() << " ===" << std::endl;
+  }
+
+  return changed;
+}
+
+void GVN::getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const {
+  // GVN依赖以下分析：
+  // 1. 支配树分析 - 用于检查指令的支配关系，确保替换的安全性
+  analysisDependencies.insert(&DominatorTreeAnalysisPass::ID);
+  
+  // 2. 副作用分析 - 用于判断函数调用是否可以进行GVN
+  analysisDependencies.insert(&SysYSideEffectAnalysisPass::ID);
+
+  // GVN不会使任何分析失效，因为：
+  // - GVN只删除冗余计算，不改变CFG结构
+  // - GVN不修改程序的语义，只是消除重复计算
+  // - 支配关系保持不变
+  // - 副作用分析结果保持不变
+  // analysisInvalidations 保持为空
+  
+  if (DEBUG) {
+    std::cout << "GVN: Declared analysis dependencies (DominatorTree, SideEffectAnalysis)" << std::endl;
+  }
+}
+
+// ======================================================================
+// GVNContext 类的实现 - 重构版本
+// ======================================================================
+
+// 简单的表达式哈希结构
+struct ExpressionKey {
+  enum Type { BINARY, UNARY, LOAD, GEP, CALL } type;
+  int opcode;
+  std::vector<Value*> operands;
+  Type* resultType;
+  
+  bool operator==(const ExpressionKey& other) const {
+    return type == other.type && opcode == other.opcode && 
+           operands == other.operands && resultType == other.resultType;
+  }
+};
+
+struct ExpressionKeyHash {
+  size_t operator()(const ExpressionKey& key) const {
+    size_t hash = std::hash<int>()(static_cast<int>(key.type)) ^ 
+                  std::hash<int>()(key.opcode);
+    for (auto op : key.operands) {
+      hash ^= std::hash<Value*>()(op) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
+    }
+    return hash;
+  }
+};
+
+void GVNContext::run(Function *func, AnalysisManager *AM, bool &changed) {
+  if (DEBUG) {
+    std::cout << "  Starting GVN analysis for function: " << func->getName() << std::endl;
+  }
+
+  // 获取分析结果
+  if (AM) {
+    domTree = AM->getAnalysisResult<DominatorTree, DominatorTreeAnalysisPass>(func);
+    sideEffectAnalysis = AM->getAnalysisResult<SideEffectAnalysisResult, SysYSideEffectAnalysisPass>();
+
+    if (DEBUG) {
+      if (domTree) {
+        std::cout << "    GVN: Using dominator tree analysis" << std::endl;
+      } else {
+        std::cout << "    GVN: Warning - dominator tree analysis not available" << std::endl;
+      }
+      if (sideEffectAnalysis) {
+        std::cout << "    GVN: Using side effect analysis" << std::endl;
+      } else {
+        std::cout << "    GVN: Warning - side effect analysis not available" << std::endl;
+      }
+    }
+  }
+
+  // 清空状态
+  valueToNumber.clear();
+  numberToValue.clear();
+  expressionToNumber.clear();
+  nextValueNumber = 1;
+  visited.clear();
+  rpoBlocks.clear();
+  needRemove.clear();
+
+  // 计算逆后序遍历
+  computeRPO(func);
+
+  if (DEBUG) {
+    std::cout << "    Computed RPO with " << rpoBlocks.size() << " blocks" << std::endl;
+  }
+
+  // 按逆后序遍历基本块进行GVN
+  int blockCount = 0;
+  for (auto bb : rpoBlocks) {
+    if (DEBUG) {
+      std::cout << "    Processing block " << ++blockCount << "/" << rpoBlocks.size() 
+                << ": " << bb->getName() << std::endl;
+    }
+    
+    processBasicBlock(bb, changed);
+  }
+
+  if (DEBUG) {
+    std::cout << "    Found " << needRemove.size() << " redundant instructions to remove" << std::endl;
+  }
+
+  // 删除冗余指令
+  eliminateRedundantInstructions(changed);
+
+  if (DEBUG) {
+    std::cout << "  GVN analysis completed for function: " << func->getName() << std::endl;
+    std::cout << "    Total values numbered: " << valueToNumber.size() << std::endl;
+    std::cout << "    Instructions eliminated: " << needRemove.size() << std::endl;
+  }
+}
+
+void GVNContext::computeRPO(Function *func) {
+  rpoBlocks.clear();
+  visited.clear();
+
+  auto entry = func->getEntryBlock();
+  if (entry) {
+    dfs(entry);
+    std::reverse(rpoBlocks.begin(), rpoBlocks.end());
+  }
+}
+
+void GVNContext::dfs(BasicBlock *bb) {
+  if (!bb || visited.count(bb)) {
+    return;
+  }
+
+  visited.insert(bb);
+
+  // 访问所有后继基本块
+  for (auto succ : bb->getSuccessors()) {
+    if (visited.find(succ) == visited.end()) {
+      dfs(succ);
+    }
+  }
+
+  rpoBlocks.push_back(bb);
+}
+
+unsigned GVNContext::getValueNumber(Value* value) {
+  // 如果已经有值编号，直接返回
+  auto it = valueToNumber.find(value);
+  if (it != valueToNumber.end()) {
+    return it->second;
+  }
+  
+  // 为新值分配编号
+  return assignValueNumber(value);
+}
+
+unsigned GVNContext::assignValueNumber(Value* value) {
+  unsigned number = nextValueNumber++;
+  valueToNumber[value] = number;
+  numberToValue[number] = value;
+  
+  if (DEBUG >= 2) {
+    std::cout << "            Assigned value number " << number 
+              << " to " << value->getName() << std::endl;
+  }
+  
+  return number;
+}
+
+void GVNContext::processBasicBlock(BasicBlock* bb, bool& changed) {
+  int instCount = 0;
+  for (auto &instPtr : bb->getInstructions()) {
+    if (DEBUG) {
+      std::cout << "      Processing instruction " << ++instCount 
+                << ": " << instPtr->getName() << std::endl;
+    }
+    
+    if (processInstruction(instPtr.get())) {
+      changed = true;
+    }
+  }
+}
+
+bool GVNContext::processInstruction(Instruction* inst) {
+  // 跳过分支指令和其他不可优化的指令
+  if (inst->isBranch() || dynamic_cast<ReturnInst*>(inst) || 
+      dynamic_cast<AllocaInst*>(inst) || dynamic_cast<StoreInst*>(inst)) {
+    
+    // 如果是store指令，需要使相关的内存值失效
+    if (auto store = dynamic_cast<StoreInst*>(inst)) {
+      invalidateMemoryValues(store);
+    }
+    
+    // 为这些指令分配值编号但不尝试优化
+    getValueNumber(inst);
+    return false;
+  }
+  
+  if (DEBUG) {
+    std::cout << "        Processing optimizable instruction: " << inst->getName() 
+              << " (kind: " << static_cast<int>(inst->getKind()) << ")" << std::endl;
+  }
+  
+  // 构建表达式键
+  std::string exprKey = buildExpressionKey(inst);
+  if (exprKey.empty()) {
+    // 不可优化的指令，只分配值编号
+    getValueNumber(inst);
+    return false;
+  }
+  
+  if (DEBUG >= 2) {
+    std::cout << "          Expression key: " << exprKey << std::endl;
+  }
+  
+  // 查找已存在的等价值
+  Value* existing = findExistingValue(exprKey, inst);
+  if (existing && existing != inst) {
+    // 检查支配关系
+    if (auto existingInst = dynamic_cast<Instruction*>(existing)) {
+      if (dominates(existingInst, inst)) {
+        if (DEBUG) {
+          std::cout << "        GVN: Replacing " << inst->getName() 
+                    << " with existing " << existing->getName() << std::endl;
+        }
+        
+        // 用已存在的值替换当前指令
+        inst->replaceAllUsesWith(existing);
+        needRemove.insert(inst);
+        
+        // 将当前指令的值编号指向已存在的值
+        unsigned existingNumber = getValueNumber(existing);
+        valueToNumber[inst] = existingNumber;
+        
+        return true;
+      } else {
+        if (DEBUG) {
+          std::cout << "          Found equivalent but dominance check failed" << std::endl;
+        }
+      }
+    }
+  }
+  
+  // 没有找到等价值，为这个表达式分配新的值编号
+  unsigned number = assignValueNumber(inst);
+  expressionToNumber[exprKey] = number;
+  
+  if (DEBUG) {
+    std::cout << "        Instruction " << inst->getName() << " is unique" << std::endl;
+  }
+  
+  return false;
+}
+
+std::string GVNContext::buildExpressionKey(Instruction* inst) {
+  std::ostringstream oss;
+  
+  if (auto binary = dynamic_cast<BinaryInst*>(inst)) {
+    oss << "binary_" << static_cast<int>(binary->getKind()) << "_";
+    oss << getValueNumber(binary->getLhs()) << "_" << getValueNumber(binary->getRhs());
+    
+    // 对于可交换操作，确保操作数顺序一致
+    if (binary->isCommutative()) {
+      unsigned lhsNum = getValueNumber(binary->getLhs());
+      unsigned rhsNum = getValueNumber(binary->getRhs());
+      if (lhsNum > rhsNum) {
+        oss.str("");
+        oss << "binary_" << static_cast<int>(binary->getKind()) << "_";
+        oss << rhsNum << "_" << lhsNum;
+      }
+    }
+  } else if (auto unary = dynamic_cast<UnaryInst*>(inst)) {
+    oss << "unary_" << static_cast<int>(unary->getKind()) << "_";
+    oss << getValueNumber(unary->getOperand());
+  } else if (auto gep = dynamic_cast<GetElementPtrInst*>(inst)) {
+    oss << "gep_" << getValueNumber(gep->getBasePointer());
+    for (unsigned i = 0; i < gep->getNumIndices(); ++i) {
+      oss << "_" << getValueNumber(gep->getIndex(i));
+    }
+  } else if (auto load = dynamic_cast<LoadInst*>(inst)) {
+    oss << "load_" << getValueNumber(load->getPointer());
+    oss << "_" << reinterpret_cast<uintptr_t>(load->getType()); // 类型区分
+  } else if (auto call = dynamic_cast<CallInst*>(inst)) {
+    // 只为无副作用的函数调用建立表达式
+    if (sideEffectAnalysis && sideEffectAnalysis->isPureFunction(call->getCallee())) {
+      oss << "call_" << call->getCallee()->getName();
+      for (size_t i = 1; i < call->getNumOperands(); ++i) { // 跳过函数指针
+        oss << "_" << getValueNumber(call->getOperand(i));
+      }
+    } else {
+      return ""; // 有副作用的函数调用不可优化
+    }
+  } else {
+    return ""; // 不支持的指令类型
+  }
+  
+  return oss.str();
+}
+
+Value* GVNContext::findExistingValue(const std::string& exprKey, Instruction* inst) {
+  auto it = expressionToNumber.find(exprKey);
+  if (it != expressionToNumber.end()) {
+    unsigned number = it->second;
+    auto valueIt = numberToValue.find(number);
+    if (valueIt != numberToValue.end()) {
+      Value* existing = valueIt->second;
+      
+      // 对于load指令，需要额外检查内存安全性
+      if (auto loadInst = dynamic_cast<LoadInst*>(inst)) {
+        if (auto existingLoad = dynamic_cast<LoadInst*>(existing)) {
+          if (!isMemorySafe(existingLoad, loadInst)) {
+            return nullptr;
+          }
+        }
+      }
+      
+      return existing;
+    }
+  }
+  return nullptr;
+}
+
+bool GVNContext::dominates(Instruction* a, Instruction* b) {
+  auto aBB = a->getParent();
+  auto bBB = b->getParent();
+  
+  // 同一基本块内的情况
+  if (aBB == bBB) {
+    auto &insts = aBB->getInstructions();
+    auto aIt = std::find_if(insts.begin(), insts.end(), 
+                           [a](const auto &ptr) { return ptr.get() == a; });
+    auto bIt = std::find_if(insts.begin(), insts.end(),
+                           [b](const auto &ptr) { return ptr.get() == b; });
+    
+    if (aIt == insts.end() || bIt == insts.end()) {
+      return false;
+    }
+    
+    return std::distance(insts.begin(), aIt) < std::distance(insts.begin(), bIt);
+  }
+  
+  // 不同基本块的情况，使用支配树
+  if (domTree) {
+    auto dominators = domTree->getDominators(bBB);
+    return dominators && dominators->count(aBB);
+  }
+  
+  return false; // 保守做法
+}
+
+bool GVNContext::isMemorySafe(LoadInst* earlierLoad, LoadInst* laterLoad) {
+  // 检查两个load是否访问相同的内存位置
+  unsigned earlierPtr = getValueNumber(earlierLoad->getPointer());
+  unsigned laterPtr = getValueNumber(laterLoad->getPointer());
+  
+  if (earlierPtr != laterPtr) {
+    return false; // 不同的内存位置
+  }
+  
+  // 检查类型是否匹配
+  if (earlierLoad->getType() != laterLoad->getType()) {
+    return false;
+  }
+  
+  // 简单情况：如果在同一个基本块且没有中间的store，则安全
+  auto earlierBB = earlierLoad->getParent();
+  auto laterBB = laterLoad->getParent();
+  
+  if (earlierBB != laterBB) {
+    // 跨基本块的情况需要更复杂的分析，暂时保守处理
+    return false;
+  }
+  
+  // 同一基本块内检查是否有中间的store
+  auto &insts = earlierBB->getInstructions();
+  auto earlierIt = std::find_if(insts.begin(), insts.end(),
+                               [earlierLoad](const auto &ptr) { return ptr.get() == earlierLoad; });
+  auto laterIt = std::find_if(insts.begin(), insts.end(),
+                              [laterLoad](const auto &ptr) { return ptr.get() == laterLoad; });
+  
+  if (earlierIt == insts.end() || laterIt == insts.end()) {
+    return false;
+  }
+  
+  // 确保earlierLoad真的在laterLoad之前
+  if (std::distance(insts.begin(), earlierIt) >= std::distance(insts.begin(), laterIt)) {
+    return false;
+  }
+  
+  // 检查中间是否有store指令修改了相同的内存位置
+  for (auto it = std::next(earlierIt); it != laterIt; ++it) {
+    if (auto store = dynamic_cast<StoreInst*>(it->get())) {
+      unsigned storePtr = getValueNumber(store->getPointer());
+      if (storePtr == earlierPtr) {
+        return false; // 找到中间的store
+      }
+    }
+    
+    // 检查函数调用是否可能修改内存
+    if (auto call = dynamic_cast<CallInst*>(it->get())) {
+      if (sideEffectAnalysis && !sideEffectAnalysis->isPureFunction(call->getCallee())) {
+        // 保守处理：有副作用的函数可能修改内存
+        return false;
+      }
+    }
+  }
+  
+  return true; // 安全
+}
+
+void GVNContext::invalidateMemoryValues(StoreInst* store) {
+  unsigned storePtr = getValueNumber(store->getPointer());
+  
+  if (DEBUG) {
+    std::cout << "        Invalidating memory values affected by store" << std::endl;
+  }
+  
+  // 找到所有可能被这个store影响的load表达式
+  std::vector<std::string> toRemove;
+  
+  for (auto& [exprKey, number] : expressionToNumber) {
+    if (exprKey.find("load_" + std::to_string(storePtr)) == 0) {
+      toRemove.push_back(exprKey);
+      if (DEBUG) {
+        std::cout << "          Invalidating expression: " << exprKey << std::endl;
+      }
+    }
+  }
+  
+  // 移除失效的表达式
+  for (const auto& key : toRemove) {
+    expressionToNumber.erase(key);
+  }
+}
+
+void GVNContext::eliminateRedundantInstructions(bool& changed) {
+  int removeCount = 0;
+  for (auto inst : needRemove) {
+    if (DEBUG) {
+      std::cout << "    Removing redundant instruction " << ++removeCount 
+                << "/" << needRemove.size() << ": " << inst->getName() << std::endl;
+    }
+    
+    // 删除指令前先断开所有使用关系
+    // inst->replaceAllUsesWith 已在 processInstruction 中调用
+    SysYIROptUtils::usedelete(inst);
+    changed = true;
+  }
+}
+
+} // namespace sysy

src/midend/Pass/Optimize/InductionVariableElimination.cpp

@@ -0,0 +1,916 @@
+#include "InductionVariableElimination.h"
+#include "LoopCharacteristics.h"
+#include "Loop.h"
+#include "Dom.h"
+#include "SideEffectAnalysis.h"
+#include "AliasAnalysis.h"
+#include "SysYIROptUtils.h"
+#include <iostream>
+#include <algorithm>
+
+// 使用全局调试开关
+extern int DEBUG;
+
+namespace sysy {
+
+// 定义 Pass 的唯一 ID
+void *InductionVariableElimination::ID = (void *)&InductionVariableElimination::ID;
+
+bool InductionVariableElimination::runOnFunction(Function* F, AnalysisManager& AM) {
+  if (F->getBasicBlocks().empty()) {
+    return false; // 空函数
+  }
+
+  if (DEBUG) {
+    std::cout << "Running InductionVariableElimination on function: " << F->getName() << std::endl;
+  }
+
+  // 创建优化上下文并运行
+  InductionVariableEliminationContext context;
+  bool modified = context.run(F, AM);
+
+  if (DEBUG) {
+    std::cout << "InductionVariableElimination " << (modified ? "modified" : "did not modify") 
+              << " function: " << F->getName() << std::endl;
+  }
+
+  return modified;
+}
+
+void InductionVariableElimination::getAnalysisUsage(std::set<void*>& analysisDependencies, 
+                                                   std::set<void*>& analysisInvalidations) const {
+  // 依赖的分析
+  analysisDependencies.insert(&LoopAnalysisPass::ID);
+  analysisDependencies.insert(&LoopCharacteristicsPass::ID);
+  analysisDependencies.insert(&DominatorTreeAnalysisPass::ID);
+  analysisDependencies.insert(&SysYSideEffectAnalysisPass::ID);
+  analysisDependencies.insert(&SysYAliasAnalysisPass::ID);
+  
+  // 会使失效的分析（归纳变量消除会修改IR结构）
+  analysisInvalidations.insert(&LoopCharacteristicsPass::ID);
+  // 注意：支配树分析通常不会因为归纳变量消除而失效，因为我们不改变控制流
+}
+
+// ========== InductionVariableEliminationContext 实现 ==========
+
+bool InductionVariableEliminationContext::run(Function* F, AnalysisManager& AM) {
+  if (DEBUG) {
+    std::cout << "  Starting induction variable elimination analysis..." << std::endl;
+  }
+
+  // 获取必要的分析结果
+  loopAnalysis = AM.getAnalysisResult<LoopAnalysisResult, LoopAnalysisPass>(F);
+  if (!loopAnalysis || !loopAnalysis->hasLoops()) {
+    if (DEBUG) {
+      std::cout << "  No loops found, skipping induction variable elimination" << std::endl;
+    }
+    return false;
+  }
+
+  loopCharacteristics = AM.getAnalysisResult<LoopCharacteristicsResult, LoopCharacteristicsPass>(F);
+  if (!loopCharacteristics) {
+    if (DEBUG) {
+      std::cout << "  LoopCharacteristics analysis not available" << std::endl;
+    }
+    return false;
+  }
+
+  dominatorTree = AM.getAnalysisResult<DominatorTree, DominatorTreeAnalysisPass>(F);
+  if (!dominatorTree) {
+    if (DEBUG) {
+      std::cout << "  DominatorTree analysis not available" << std::endl;
+    }
+    return false;
+  }
+
+  sideEffectAnalysis = AM.getAnalysisResult<SideEffectAnalysisResult, SysYSideEffectAnalysisPass>();
+  if (!sideEffectAnalysis) {
+    if (DEBUG) {
+      std::cout << "  SideEffectAnalysis not available, using conservative approach" << std::endl;
+    }
+    // 可以继续执行，但会使用更保守的策略
+  } else {
+    if (DEBUG) {
+      std::cout << "  Using SideEffectAnalysis for safety checks" << std::endl;
+    }
+  }
+
+  aliasAnalysis = AM.getAnalysisResult<AliasAnalysisResult, SysYAliasAnalysisPass>(F);
+  if (!aliasAnalysis) {
+    if (DEBUG) {
+      std::cout << "  AliasAnalysis not available, using conservative approach" << std::endl;
+    }
+    // 可以继续执行，但会使用更保守的策略
+  } else {
+    if (DEBUG) {
+      std::cout << "  Using AliasAnalysis for memory safety checks" << std::endl;
+    }
+  }
+
+  // 执行三个阶段的优化
+  
+  // 阶段1：识别死归纳变量
+  identifyDeadInductionVariables(F);
+  
+  if (deadIVs.empty()) {
+    if (DEBUG) {
+      std::cout << "  No dead induction variables found" << std::endl;
+    }
+    return false;
+  }
+
+  if (DEBUG) {
+    std::cout << "  Found " << deadIVs.size() << " potentially dead induction variables" << std::endl;
+  }
+
+  // 阶段2：分析安全性
+  analyzeSafetyForElimination();
+
+  // 阶段3：执行消除
+  bool modified = performInductionVariableElimination();
+
+  if (DEBUG) {
+    printDebugInfo();
+  }
+
+  return modified;
+}
+
+void InductionVariableEliminationContext::identifyDeadInductionVariables(Function* F) {
+  if (DEBUG) {
+    std::cout << "  === Phase 1: Identifying Dead Induction Variables ===" << std::endl;
+  }
+
+  // 遍历所有循环
+  for (const auto& loop_ptr : loopAnalysis->getAllLoops()) {
+    Loop* loop = loop_ptr.get();
+    
+    if (DEBUG) {
+      std::cout << "    Analyzing loop: " << loop->getName() << std::endl;
+    }
+
+    // 获取循环特征
+    const LoopCharacteristics* characteristics = loopCharacteristics->getCharacteristics(loop);
+    if (!characteristics) {
+      if (DEBUG) {
+        std::cout << "      No characteristics available for loop" << std::endl;
+      }
+      continue;
+    }
+
+    if (characteristics->InductionVars.empty()) {
+      if (DEBUG) {
+        std::cout << "      No induction variables found in loop" << std::endl;
+      }
+      continue;
+    }
+
+    // 检查每个归纳变量是否为死归纳变量
+    for (const auto& iv : characteristics->InductionVars) {
+      auto deadIV = isDeadInductionVariable(iv.get(), loop);
+      if (deadIV) {
+        if (DEBUG) {
+          std::cout << "      Found potential dead IV: %" << deadIV->phiInst->getName() << std::endl;
+        }
+        
+        // 添加到候选项列表
+        loopToDeadIVs[loop].push_back(deadIV.get());
+        deadIVs.push_back(std::move(deadIV));
+      }
+    }
+  }
+
+  if (DEBUG) {
+    std::cout << "  === End Phase 1: Found " << deadIVs.size() << " candidates ===" << std::endl;
+  }
+}
+
+std::unique_ptr<DeadInductionVariable> 
+InductionVariableEliminationContext::isDeadInductionVariable(const InductionVarInfo* iv, Loop* loop) {
+  // 获取 phi 指令
+  auto* phiInst = dynamic_cast<PhiInst*>(iv->div);
+  if (!phiInst) {
+    return nullptr; // 不是 phi 指令
+  }
+
+  // 新的逻辑：递归分析整个use-def链，判断是否有真实的使用
+  if (!isPhiInstructionDeadRecursively(phiInst, loop)) {
+    return nullptr; // 有真实的使用，不能删除
+  }
+
+  // 创建死归纳变量信息
+  auto deadIV = std::make_unique<DeadInductionVariable>(phiInst, loop);
+  deadIV->relatedInsts = collectRelatedInstructions(phiInst, loop);
+  
+  return deadIV;
+}
+
+// 递归分析phi指令及其使用链是否都是死代码
+bool InductionVariableEliminationContext::isPhiInstructionDeadRecursively(PhiInst* phiInst, Loop* loop) {
+  if (DEBUG) {
+    std::cout << "      递归分析归纳变量 " << phiInst->getName() << " 的完整使用链" << std::endl;
+  }
+
+  // 使用访问集合避免无限递归
+  std::set<Instruction*> visitedInstructions;
+  std::set<Instruction*> currentPath; // 用于检测循环依赖
+  
+  // 核心逻辑：递归分析使用链，寻找任何"逃逸点"
+  return isInstructionUseChainDeadRecursively(phiInst, loop, visitedInstructions, currentPath);
+}
+
+// 递归分析指令的使用链是否都是死代码
+bool InductionVariableEliminationContext::isInstructionUseChainDeadRecursively(
+    Instruction* inst, Loop* loop, 
+    std::set<Instruction*>& visited, 
+    std::set<Instruction*>& currentPath) {
+  
+  if (DEBUG && visited.size() < 10) { // 限制debug输出
+    std::cout << "        分析指令 " << inst->getName() << " (" << inst->getKindString() << ")" << std::endl;
+  }
+  
+  // 避免无限递归
+  if (currentPath.count(inst) > 0) {
+    // 发现循环依赖，这在归纳变量中是正常的，继续分析其他路径
+    if (DEBUG && visited.size() < 10) {
+      std::cout << "          发现循环依赖，继续分析其他路径" << std::endl;
+    }
+    return true; // 循环依赖本身不是逃逸点
+  }
+  
+  if (visited.count(inst) > 0) {
+    // 已经分析过这个指令
+    return true; // 假设之前的分析是正确的
+  }
+  
+  visited.insert(inst);
+  currentPath.insert(inst);
+  
+  // 1. 检查是否有副作用（逃逸点）
+  if (sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(inst)) {
+    if (DEBUG && visited.size() < 10) {
+      std::cout << "          指令有副作用，是逃逸点" << std::endl;
+    }
+    currentPath.erase(inst);
+    return false; // 有副作用的指令是逃逸点
+  }
+  
+  // 1.5. 特殊检查：控制流指令永远不是死代码
+  auto instKind = inst->getKind();
+  if (instKind == Instruction::Kind::kCondBr || 
+      instKind == Instruction::Kind::kBr ||
+      instKind == Instruction::Kind::kReturn) {
+    if (DEBUG && visited.size() < 10) {
+      std::cout << "          控制流指令，是逃逸点" << std::endl;
+    }
+    currentPath.erase(inst);
+    return false; // 控制流指令是逃逸点
+  }
+  
+  // 2. 检查指令的所有使用
+  bool allUsesAreDead = true;
+  for (auto use : inst->getUses()) {
+    auto user = use->getUser();
+    auto* userInst = dynamic_cast<Instruction*>(user);
+    
+    if (!userInst) {
+      // 被非指令使用（如函数返回值），是逃逸点
+      if (DEBUG && visited.size() < 10) {
+        std::cout << "          被非指令使用，是逃逸点" << std::endl;
+      }
+      allUsesAreDead = false;
+      break;
+    }
+    
+    // 检查使用是否在循环外（逃逸点）
+    if (!loop->contains(userInst->getParent())) {
+      if (DEBUG && visited.size() < 10) {
+        std::cout << "          在循环外被 " << userInst->getName() << " 使用，是逃逸点" << std::endl;
+      }
+      allUsesAreDead = false;
+      break;
+    }
+    
+    // 特殊检查：如果使用者是循环的退出条件，需要进一步分析
+    // 对于用于退出条件的归纳变量，需要更谨慎的处理
+    if (isUsedInLoopExitCondition(userInst, loop)) {
+      // 修复逻辑：用于循环退出条件的归纳变量通常不应该被消除
+      // 除非整个循环都可以被证明是完全无用的（这需要更复杂的分析）
+      if (DEBUG && visited.size() < 10) {
+        std::cout << "          被用于循环退出条件，是逃逸点（避免破坏循环语义）" << std::endl;
+      }
+      allUsesAreDead = false;
+      break;
+    }
+    
+    // 递归分析使用者的使用链
+    if (!isInstructionUseChainDeadRecursively(userInst, loop, visited, currentPath)) {
+      allUsesAreDead = false;
+      break; // 找到逃逸点，不需要继续分析
+    }
+  }
+  
+  currentPath.erase(inst);
+  
+  if (allUsesAreDead && DEBUG && visited.size() < 10) {
+    std::cout << "          指令 " << inst->getName() << " 的所有使用都是死代码" << std::endl;
+  }
+  
+  return allUsesAreDead;
+}
+
+// 检查循环是否有副作用
+bool InductionVariableEliminationContext::loopHasSideEffects(Loop* loop) {
+  // 遍历循环中的所有指令，检查是否有副作用
+  for (BasicBlock* bb : loop->getBlocks()) {
+    for (auto& inst : bb->getInstructions()) {
+      Instruction* instPtr = inst.get();
+      
+      // 使用副作用分析（如果可用）
+      if (sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(instPtr)) {
+        if (DEBUG) {
+          std::cout << "          循环中发现有副作用的指令: " << instPtr->getName() << std::endl;
+        }
+        return true;
+      }
+      
+      // 如果没有副作用分析，使用保守的判断
+      if (!sideEffectAnalysis) {
+        auto kind = instPtr->getKind();
+        // 这些指令通常有副作用
+        if (kind == Instruction::Kind::kCall ||
+            kind == Instruction::Kind::kStore ||
+            kind == Instruction::Kind::kReturn) {
+          if (DEBUG) {
+            std::cout << "          循环中发现潜在有副作用的指令: " << instPtr->getName() << std::endl;
+          }
+          return true;
+        }
+      }
+    }
+  }
+  
+  // 重要修复：检查是否为嵌套循环的外层循环
+  // 如果当前循环包含其他循环，那么它有潜在的副作用
+  for (const auto& loop_ptr : loopAnalysis->getAllLoops()) {
+    Loop* otherLoop = loop_ptr.get();
+    if(loopAnalysis->getLowestCommonAncestor(otherLoop, loop) == loop) {
+      if (DEBUG) {
+        std::cout << "          循环 " << loop->getName() << " 是其他循环的外层循环，视为有副作用" << std::endl;
+      }
+      return true; // 外层循环被视为有副作用
+    }
+    // if (otherLoop != loop && loop->contains(otherLoop->getHeader())) {
+    //   if (DEBUG) {
+    //     std::cout << "          循环 " << loop->getName() << " 包含子循环 " << otherLoop->getName() << "，视为有副作用" << std::endl;
+    //   }
+    //   return true; // 包含子循环的外层循环被视为有副作用
+    // }
+  }
+  
+  if (DEBUG) {
+    std::cout << "          循环 " << loop->getName() << " 无副作用" << std::endl;
+  }
+  return false; // 循环无副作用
+}
+
+// 检查指令是否被用于循环退出条件
+bool InductionVariableEliminationContext::isUsedInLoopExitCondition(Instruction* inst, Loop* loop) {
+  // 检查指令是否被循环的退出条件使用
+  for (BasicBlock* exitingBB : loop->getExitingBlocks()) {
+    auto terminatorIt = exitingBB->terminator();
+    if (terminatorIt != exitingBB->end()) {
+      Instruction* terminator = terminatorIt->get();
+      if (terminator) {
+        // 检查终结指令的操作数
+        for (size_t i = 0; i < terminator->getNumOperands(); ++i) {
+          if (terminator->getOperand(i) == inst) {
+            if (DEBUG) {
+              std::cout << "          指令 " << inst->getName() << " 用于循环退出条件" << std::endl;
+            }
+            return true;
+          }
+        }
+        
+        // 对于条件分支，还需要检查条件指令的操作数
+        if (terminator->getKind() == Instruction::Kind::kCondBr) {
+          auto* condBr = dynamic_cast<CondBrInst*>(terminator);
+          if (condBr) {
+            Value* condition = condBr->getCondition();
+            if (condition == inst) {
+              if (DEBUG) {
+                std::cout << "          指令 " << inst->getName() << " 是循环条件" << std::endl;
+              }
+              return true;
+            }
+            
+            // 递归检查条件指令的操作数（比如比较指令）
+            auto* condInst = dynamic_cast<Instruction*>(condition);
+            if (condInst) {
+              for (size_t i = 0; i < condInst->getNumOperands(); ++i) {
+                if (condInst->getOperand(i) == inst) {
+                  if (DEBUG) {
+                    std::cout << "          指令 " << inst->getName() << " 用于循环条件的操作数" << std::endl;
+                  }
+                  return true;
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  
+  return false;
+}
+
+
+// 检查指令的结果是否未被有效使用
+bool InductionVariableEliminationContext::isInstructionResultUnused(Instruction* inst, Loop* loop) {
+  // 检查指令的所有使用
+  if (inst->getUses().empty()) {
+    return true; // 没有使用，肯定是未使用
+  }
+  
+  for (auto use : inst->getUses()) {
+    auto user = use->getUser();
+    auto* userInst = dynamic_cast<Instruction*>(user);
+    
+    if (!userInst) {
+      return false; // 被非指令使用，认为是有效使用
+    }
+    
+    // 如果在循环外被使用，认为是有效使用
+    if (!loop->contains(userInst->getParent())) {
+      return false;
+    }
+    
+    // 递归检查使用这个结果的指令是否也是死代码
+    // 为了避免无限递归，限制递归深度
+    if (!isInstructionEffectivelyDead(userInst, loop, 3)) {
+      return false; // 存在有效使用
+    }
+  }
+  
+  return true; // 所有使用都是无效的
+}
+
+// 检查store指令是否存储到死地址（利用别名分析）
+bool InductionVariableEliminationContext::isStoreToDeadLocation(StoreInst* store, Loop* loop) {
+  if (!aliasAnalysis) {
+    return false; // 没有别名分析，保守返回false
+  }
+  
+  Value* storePtr = store->getPointer();
+  
+  // 检查是否存储到局部临时变量且该变量在循环外不被读取
+  const MemoryLocation* memLoc = aliasAnalysis->getMemoryLocation(storePtr);
+  if (!memLoc) {
+    return false; // 无法确定内存位置
+  }
+  
+  // 如果是局部数组且只在循环内被访问
+  if (memLoc->isLocalArray) {
+    // 检查该内存位置是否在循环外被读取
+    for (auto* accessInst : memLoc->accessInsts) {
+      if (accessInst->getKind() == Instruction::Kind::kLoad) {
+        if (!loop->contains(accessInst->getParent())) {
+          return false; // 在循环外被读取，不是死存储
+        }
+      }
+    }
+    
+    if (DEBUG) {
+      std::cout << "            存储到局部数组且仅在循环内访问" << std::endl;
+    }
+    return true; // 存储到仅循环内访问的局部数组
+  }
+  
+  return false;
+}
+
+// 检查指令是否有效死代码（带递归深度限制）
+bool InductionVariableEliminationContext::isInstructionEffectivelyDead(Instruction* inst, Loop* loop, int maxDepth) {
+  if (maxDepth <= 0) {
+    return false; // 达到递归深度限制，保守返回false
+  }
+  
+  // 利用副作用分析
+  if (sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(inst)) {
+    return false; // 有副作用的指令不是死代码
+  }
+  
+  // 检查特殊指令类型
+  switch (inst->getKind()) {
+    case Instruction::Kind::kStore:
+      // Store指令可能是死存储
+      return isStoreToDeadLocation(dynamic_cast<StoreInst*>(inst), loop);
+    
+    case Instruction::Kind::kCall:
+      // 函数调用通常有副作用
+      if (sideEffectAnalysis) {
+        return !sideEffectAnalysis->hasSideEffect(inst);
+      }
+      return false; // 保守地认为函数调用有效果
+    
+    case Instruction::Kind::kReturn:
+    case Instruction::Kind::kBr:
+    case Instruction::Kind::kCondBr:
+      // 控制流指令不是死代码
+      return false;
+    
+    default:
+      // 其他指令检查其使用是否有效
+      break;
+  }
+  
+  // 检查指令的使用
+  if (inst->getUses().empty()) {
+    return true; // 没有使用的纯指令是死代码
+  }
+  
+  // 递归检查所有使用
+  for (auto use : inst->getUses()) {
+    auto user = use->getUser();
+    auto* userInst = dynamic_cast<Instruction*>(user);
+    
+    if (!userInst) {
+      return false; // 被非指令使用
+    }
+    
+    if (!loop->contains(userInst->getParent())) {
+      return false; // 在循环外被使用
+    }
+    
+    // 递归检查使用者
+    if (!isInstructionEffectivelyDead(userInst, loop, maxDepth - 1)) {
+      return false; // 存在有效使用
+    }
+  }
+  
+  return true; // 所有使用都是死代码
+}
+
+// 原有的函数保持兼容，但现在使用增强的死代码分析
+bool InductionVariableEliminationContext::isInstructionDeadOrInternalOnly(Instruction* inst, Loop* loop) {
+  return isInstructionEffectivelyDead(inst, loop, 5);
+}
+
+// 检查store指令是否有后续的load操作
+bool InductionVariableEliminationContext::hasSubsequentLoad(StoreInst* store, Loop* loop) {
+  if (!aliasAnalysis) {
+    // 没有别名分析，保守地假设有后续读取
+    return true;
+  }
+  
+  Value* storePtr = store->getPointer();
+  const MemoryLocation* storeLoc = aliasAnalysis->getMemoryLocation(storePtr);
+  
+  if (!storeLoc) {
+    // 无法确定内存位置，保守处理
+    return true;
+  }
+  
+  // 在循环中和循环后查找对同一位置的load操作
+  std::vector<BasicBlock*> blocksToCheck;
+  
+  // 添加循环内的所有基本块
+  for (auto* bb : loop->getBlocks()) {
+    blocksToCheck.push_back(bb);
+  }
+  
+  // 添加循环的退出块
+  auto exitBlocks = loop->getExitBlocks();
+  for (auto* exitBB : exitBlocks) {
+    blocksToCheck.push_back(exitBB);
+  }
+  
+  // 搜索load操作
+  for (auto* bb : blocksToCheck) {
+    for (auto& inst : bb->getInstructions()) {
+      if (inst->getKind() == Instruction::Kind::kLoad) {
+        LoadInst* loadInst = static_cast<LoadInst*>(inst.get());
+        Value* loadPtr = loadInst->getPointer();
+        const MemoryLocation* loadLoc = aliasAnalysis->getMemoryLocation(loadPtr);
+        
+        if (loadLoc && aliasAnalysis->queryAlias(storePtr, loadPtr) != AliasType::NO_ALIAS) {
+          // 找到可能读取同一位置的load操作
+          if (DEBUG) {
+            std::cout << "            找到后续load操作: " << loadInst->getName() << std::endl;
+          }
+          return true;
+        }
+      }
+    }
+  }
+  
+  // 检查是否通过函数调用间接访问
+  for (auto* bb : blocksToCheck) {
+    for (auto& inst : bb->getInstructions()) {
+      if (inst->getKind() == Instruction::Kind::kCall) {
+        CallInst* callInst = static_cast<CallInst*>(inst.get());
+        if (callInst && sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(callInst)) {
+          // 函数调用可能间接读取内存
+          if (DEBUG) {
+            std::cout << "            函数调用可能读取内存: " << callInst->getName() << std::endl;
+          }
+          return true;
+        }
+      }
+    }
+  }
+  
+  if (DEBUG) {
+    std::cout << "            未找到后续load操作" << std::endl;
+  }
+  return false; // 没有找到后续读取
+}
+
+// 检查指令是否在循环外有使用
+bool InductionVariableEliminationContext::hasUsageOutsideLoop(Instruction* inst, Loop* loop) {
+  for (auto use : inst->getUses()) {
+    auto user = use->getUser();
+    auto* userInst = dynamic_cast<Instruction*>(user);
+    
+    if (!userInst) {
+      // 被非指令使用，可能在循环外
+      return true;
+    }
+    
+    if (!loop->contains(userInst->getParent())) {
+      // 在循环外被使用
+      if (DEBUG) {
+        std::cout << "            指令 " << inst->getName() << " 在循环外被 " 
+                  << userInst->getName() << " 使用" << std::endl;
+      }
+      return true;
+    }
+  }
+  
+  return false; // 没有循环外使用
+}
+
+// 检查store指令是否在循环外有后续的load操作
+bool InductionVariableEliminationContext::hasSubsequentLoadOutsideLoop(StoreInst* store, Loop* loop) {
+  if (!aliasAnalysis) {
+    // 没有别名分析，保守地假设有后续读取
+    return true;
+  }
+  
+  Value* storePtr = store->getPointer();
+  
+  // 检查循环的退出块及其后继
+  auto exitBlocks = loop->getExitBlocks();
+  std::set<BasicBlock*> visitedBlocks;
+  
+  for (auto* exitBB : exitBlocks) {
+    if (hasLoadInSubtree(exitBB, storePtr, visitedBlocks)) {
+      if (DEBUG) {
+        std::cout << "            找到循环外的后续load操作" << std::endl;
+      }
+      return true;
+    }
+  }
+  
+  return false; // 没有找到循环外的后续读取
+}
+
+// 递归检查基本块子树中是否有对指定位置的load操作
+bool InductionVariableEliminationContext::hasLoadInSubtree(BasicBlock* bb, Value* ptr, std::set<BasicBlock*>& visited) {
+  if (visited.count(bb) > 0) {
+    return false; // 已经访问过，避免无限循环
+  }
+  visited.insert(bb);
+  
+  // 检查当前基本块中的指令
+  for (auto& inst : bb->getInstructions()) {
+    if (inst->getKind() == Instruction::Kind::kLoad) {
+      LoadInst* loadInst = static_cast<LoadInst*>(inst.get());
+      if (aliasAnalysis && aliasAnalysis->queryAlias(ptr, loadInst->getPointer()) != AliasType::NO_ALIAS) {
+        return true; // 找到了对相同或别名位置的load
+      }
+    } else if (inst->getKind() == Instruction::Kind::kCall) {
+      // 函数调用可能间接读取内存
+      CallInst* callInst = static_cast<CallInst*>(inst.get());
+      if (sideEffectAnalysis && sideEffectAnalysis->hasSideEffect(callInst)) {
+        return true; // 保守地认为函数调用可能读取内存
+      }
+    }
+  }
+  
+  // 递归检查后继基本块（限制深度以避免过度搜索）
+  static int searchDepth = 0;
+  if (searchDepth < 10) { // 限制搜索深度
+    searchDepth++;
+    for (auto* succ : bb->getSuccessors()) {
+      if (hasLoadInSubtree(succ, ptr, visited)) {
+        searchDepth--;
+        return true;
+      }
+    }
+    searchDepth--;
+  }
+  
+  return false;
+}
+
+std::vector<Instruction*> InductionVariableEliminationContext::collectRelatedInstructions(
+    PhiInst* phiInst, Loop* loop) {
+  std::vector<Instruction*> relatedInsts;
+  
+  // 收集所有与该归纳变量相关的指令
+  for (auto use : phiInst->getUses()) {
+    auto user = use->getUser();
+    auto* userInst = dynamic_cast<Instruction*>(user);
+    
+    if (userInst && loop->contains(userInst->getParent())) {
+      relatedInsts.push_back(userInst);
+    }
+  }
+  
+  return relatedInsts;
+}
+
+void InductionVariableEliminationContext::analyzeSafetyForElimination() {
+  if (DEBUG) {
+    std::cout << "  === Phase 2: Analyzing Safety for Elimination ===" << std::endl;
+  }
+
+  // 为每个死归纳变量检查消除的安全性
+  for (auto& deadIV : deadIVs) {
+    bool isSafe = isSafeToEliminate(deadIV.get());
+    deadIV->canEliminate = isSafe;
+    
+    if (DEBUG) {
+      std::cout << "    Dead IV " << deadIV->phiInst->getName() 
+                << ": " << (isSafe ? "SAFE" : "UNSAFE") << " to eliminate" << std::endl;
+    }
+  }
+
+  if (DEBUG) {
+    size_t safeCount = 0;
+    for (const auto& deadIV : deadIVs) {
+      if (deadIV->canEliminate) safeCount++;
+    }
+    std::cout << "  === End Phase 2: " << safeCount << " of " << deadIVs.size() 
+              << " variables are safe to eliminate ===" << std::endl;
+  }
+}
+
+bool InductionVariableEliminationContext::isSafeToEliminate(const DeadInductionVariable* deadIV) {
+  // 1. 确保归纳变量在循环头
+  if (deadIV->phiInst->getParent() != deadIV->containingLoop->getHeader()) {
+    if (DEBUG) {
+      std::cout << "      Unsafe: phi not in loop header" << std::endl;
+    }
+    return false;
+  }
+  
+  // 2. 确保相关指令都在循环内
+  for (auto* inst : deadIV->relatedInsts) {
+    if (!deadIV->containingLoop->contains(inst->getParent())) {
+      if (DEBUG) {
+        std::cout << "      Unsafe: related instruction outside loop" << std::endl;
+      }
+      return false;
+    }
+  }
+  
+  // 3. 确保没有副作用
+  for (auto* inst : deadIV->relatedInsts) {
+    if (sideEffectAnalysis) {
+      // 使用副作用分析进行精确检查
+      if (sideEffectAnalysis->hasSideEffect(inst)) {
+        if (DEBUG) {
+          std::cout << "      Unsafe: related instruction " << inst->getName() 
+                    << " has side effects" << std::endl;
+        }
+        return false;
+      }
+    } else {
+      // 没有副作用分析时使用保守策略：只允许基本算术运算
+      auto kind = inst->getKind();
+      if (kind != Instruction::Kind::kAdd && 
+          kind != Instruction::Kind::kSub &&
+          kind != Instruction::Kind::kMul) {
+        if (DEBUG) {
+          std::cout << "      Unsafe: related instruction may have side effects (conservative)" << std::endl;
+        }
+        return false;
+      }
+    }
+  }
+  
+  // 4. 确保不影响循环的退出条件
+  for (BasicBlock* exitingBB : deadIV->containingLoop->getExitingBlocks()) {
+    auto terminatorIt = exitingBB->terminator();
+    if (terminatorIt != exitingBB->end()) {
+      Instruction* terminator = terminatorIt->get();
+      if (terminator) {
+        for (size_t i = 0; i < terminator->getNumOperands(); ++i) {
+          if (terminator->getOperand(i) == deadIV->phiInst) {
+            if (DEBUG) {
+              std::cout << "      Unsafe: phi used in loop exit condition" << std::endl;
+            }
+            return false;
+          }
+        }
+      }
+    }
+  }
+  
+  return true;
+}
+
+bool InductionVariableEliminationContext::performInductionVariableElimination() {
+  if (DEBUG) {
+    std::cout << "  === Phase 3: Performing Induction Variable Elimination ===" << std::endl;
+  }
+
+  bool modified = false;
+
+  for (auto& deadIV : deadIVs) {
+    if (!deadIV->canEliminate) {
+      continue;
+    }
+
+    if (DEBUG) {
+      std::cout << "    Eliminating dead IV: " << deadIV->phiInst->getName() << std::endl;
+    }
+
+    if (eliminateDeadInductionVariable(deadIV.get())) {
+      if (DEBUG) {
+        std::cout << "      Successfully eliminated: " << deadIV->phiInst->getName() << std::endl;
+      }
+      modified = true;
+    } else {
+      if (DEBUG) {
+        std::cout << "      Failed to eliminate: " << deadIV->phiInst->getName() << std::endl;
+      }
+    }
+  }
+
+  if (DEBUG) {
+    std::cout << "  === End Phase 3: " << (modified ? "Eliminations performed" : "No eliminations") << " ===" << std::endl;
+  }
+
+  return modified;
+}
+
+bool InductionVariableEliminationContext::eliminateDeadInductionVariable(DeadInductionVariable* deadIV) {
+  // 1. 删除所有相关指令
+  for (auto* inst : deadIV->relatedInsts) {
+    auto* bb = inst->getParent();
+    auto it = bb->findInstIterator(inst);
+    if (it != bb->end()) {
+        SysYIROptUtils::usedelete(it);
+    //   bb->getInstructions().erase(it);
+      if (DEBUG) {
+        std::cout << "        Removed related instruction: " << inst->getName() << std::endl;
+      }
+    }
+  }
+
+  // 2. 删除 phi 指令
+  auto* bb = deadIV->phiInst->getParent();
+  auto it = bb->findInstIterator(deadIV->phiInst);
+  if (it != bb->end()) {
+    SysYIROptUtils::usedelete(it);
+    // bb->getInstructions().erase(it);
+    if (DEBUG) {
+      std::cout << "        Removed phi instruction: " << deadIV->phiInst->getName() << std::endl;
+    }
+    return true;
+  }
+
+  return false;
+}
+
+void InductionVariableEliminationContext::printDebugInfo() {
+  if (!DEBUG) return;
+
+  std::cout << "\n=== Induction Variable Elimination Summary ===" << std::endl;
+  std::cout << "Total dead IVs found: " << deadIVs.size() << std::endl;
+  
+  size_t eliminatedCount = 0;
+  for (auto& [loop, loopDeadIVs] : loopToDeadIVs) {
+    size_t loopEliminatedCount = 0;
+    for (auto* deadIV : loopDeadIVs) {
+      if (deadIV->canEliminate) {
+        loopEliminatedCount++;
+        eliminatedCount++;
+      }
+    }
+    
+    if (loopEliminatedCount > 0) {
+      std::cout << "Loop " << loop->getName() << ": " << loopEliminatedCount 
+                << " of " << loopDeadIVs.size() << " IVs eliminated" << std::endl;
+    }
+  }
+  
+  std::cout << "Total eliminated: " << eliminatedCount << " of " << deadIVs.size() << std::endl;
+  std::cout << "=============================================" << std::endl;
+}
+
+} // namespace sysy

src/midend/Pass/Optimize/LICM.cpp

@@ -18,62 +18,214 @@ bool LICMContext::hoistInstructions() {
   // 1. 先收集所有可外提指令
   std::unordered_set<Instruction *> workSet(chars->invariantInsts.begin(), chars->invariantInsts.end());
 
+  if (DEBUG) {
+    std::cout << "LICM: Found " << workSet.size() << " candidate invariant instructions to hoist:" << std::endl;
+    for (auto *inst : workSet) {
+      std::cout << "  - " << inst->getName() << " (kind: " << static_cast<int>(inst->getKind()) 
+                << ", in BB: " << inst->getParent()->getName() << ")" << std::endl;
+    }
+  }
+
   // 2. 计算每个指令被依赖的次数（入度）
   std::unordered_map<Instruction *, int> indegree;
+  std::unordered_map<Instruction *, std::vector<Instruction *>> dependencies; // 记录依赖关系
+  std::unordered_map<Instruction *, std::vector<Instruction *>> dependents;   // 记录被依赖关系
+  
   for (auto *inst : workSet) {
     indegree[inst] = 0;
+    dependencies[inst] = {};
+    dependents[inst] = {};
   }
+  
+  if (DEBUG) {
+    std::cout << "LICM: Analyzing dependencies between invariant instructions..." << std::endl;
+  }
+  
   for (auto *inst : workSet) {
     for (size_t i = 0; i < inst->getNumOperands(); ++i) {
       if (auto *dep = dynamic_cast<Instruction *>(inst->getOperand(i))) {
         if (workSet.count(dep)) {
           indegree[inst]++;
+          dependencies[inst].push_back(dep);
+          dependents[dep].push_back(inst);
+          
+          if (DEBUG) {
+            std::cout << "  Dependency: " << inst->getName() << " depends on " << dep->getName() << std::endl;
+          }
         }
       }
     }
   }
 
+  if (DEBUG) {
+    std::cout << "LICM: Initial indegree analysis:" << std::endl;
+    for (auto &[inst, deg] : indegree) {
+      std::cout << "  " << inst->getName() << ": indegree=" << deg;
+      if (deg > 0) {
+        std::cout << ", depends on: ";
+        for (auto *dep : dependencies[inst]) {
+          std::cout << dep->getName() << " ";
+        }
+      }
+      std::cout << std::endl;
+    }
+  }
+
   // 3. Kahn拓扑排序
   std::vector<Instruction *> sorted;
   std::queue<Instruction *> q;
-  for (auto &[inst, deg] : indegree) {
-    if (deg == 0)
-      q.push(inst);
+  
+  if (DEBUG) {
+    std::cout << "LICM: Starting topological sort..." << std::endl;
   }
+  
+  for (auto &[inst, deg] : indegree) {
+    if (deg == 0) {
+      q.push(inst);
+      if (DEBUG) {
+        std::cout << "  Initial zero-indegree instruction: " << inst->getName() << std::endl;
+      }
+    }
+  }
+  
+  int sortStep = 0;
   while (!q.empty()) {
     auto *inst = q.front();
     q.pop();
     sorted.push_back(inst);
-    for (size_t i = 0; i < inst->getNumOperands(); ++i) {
-      if (auto *dep = dynamic_cast<Instruction *>(inst->getOperand(i))) {
-        if (workSet.count(dep)) {
-          indegree[dep]--;
-          if (indegree[dep] == 0)
-            q.push(dep);
+    
+    if (DEBUG) {
+      std::cout << "  Step " << (++sortStep) << ": Processing " << inst->getName() << std::endl;
+    }
+    
+    if (DEBUG) {
+      std::cout << "    Reducing indegree of dependents of " << inst->getName() << std::endl;
+    }
+    
+    // 正确的拓扑排序：当处理一个指令时，应该减少其所有使用者（dependents）的入度
+    for (auto *dependent : dependents[inst]) {
+      indegree[dependent]--;
+      if (DEBUG) {
+        std::cout << "      Reducing indegree of " << dependent->getName() << " to " << indegree[dependent] << std::endl;
+      }
+      if (indegree[dependent] == 0) {
+        q.push(dependent);
+        if (DEBUG) {
+          std::cout << "      Adding " << dependent->getName() << " to queue (indegree=0)" << std::endl;
         }
       }
     }
   }
 
-  // 检查是否全部排序，若未全部排序，说明有环（理论上不会）
+  // 检查是否全部排序，若未全部排序，打印错误信息
+  // 这可能是因为存在循环依赖或其他问题导致无法完成拓扑排序
   if (sorted.size() != workSet.size()) {
-    if (DEBUG)
-      std::cerr << "LICM: Topological sort failed, possible dependency cycle." << std::endl;
+    if (DEBUG) {
+      std::cout << "LICM: Topological sort failed! Sorted " << sorted.size() 
+                << " instructions out of " << workSet.size() << " total." << std::endl;
+      
+      // 找出未被排序的指令（形成循环依赖的指令）
+      std::unordered_set<Instruction *> remaining;
+      for (auto *inst : workSet) {
+        bool found = false;
+        for (auto *sortedInst : sorted) {
+          if (inst == sortedInst) {
+            found = true;
+            break;
+          }
+        }
+        if (!found) {
+          remaining.insert(inst);
+        }
+      }
+      
+      std::cout << "LICM: Instructions involved in dependency cycle:" << std::endl;
+      for (auto *inst : remaining) {
+        std::cout << "  - " << inst->getName() << " (indegree=" << indegree[inst] << ")" << std::endl;
+        std::cout << "    Dependencies within cycle: ";
+        for (auto *dep : dependencies[inst]) {
+          if (remaining.count(dep)) {
+            std::cout << dep->getName() << " ";
+          }
+        }
+        std::cout << std::endl;
+        std::cout << "    Dependents within cycle: ";
+        for (auto *dependent : dependents[inst]) {
+          if (remaining.count(dependent)) {
+            std::cout << dependent->getName() << " ";
+          }
+        }
+        std::cout << std::endl;
+      }
+      
+      // 尝试找出一个具体的循环路径
+      std::cout << "LICM: Attempting to trace a dependency cycle:" << std::endl;
+      if (!remaining.empty()) {
+        auto *start = *remaining.begin();
+        std::unordered_set<Instruction *> visited;
+        std::vector<Instruction *> path;
+        
+        std::function<bool(Instruction *)> findCycle = [&](Instruction *current) -> bool {
+          if (visited.count(current)) {
+            // 找到环
+            auto it = std::find(path.begin(), path.end(), current);
+            if (it != path.end()) {
+              std::cout << "  Cycle found: ";
+              for (auto cycleIt = it; cycleIt != path.end(); ++cycleIt) {
+                std::cout << (*cycleIt)->getName() << " -> ";
+              }
+              std::cout << current->getName() << std::endl;
+              return true;
+            }
+            return false;
+          }
+          
+          visited.insert(current);
+          path.push_back(current);
+          
+          for (auto *dep : dependencies[current]) {
+            if (remaining.count(dep)) {
+              if (findCycle(dep)) {
+                return true;
+              }
+            }
+          }
+          
+          path.pop_back();
+          return false;
+        };
+        
+        findCycle(start);
+      }
+    }
     return false;
   }
 
   // 4. 按拓扑序外提
+  if (DEBUG) {
+    std::cout << "LICM: Successfully completed topological sort. Hoisting instructions in order:" << std::endl;
+  }
+  
   for (auto *inst : sorted) {
     if (!inst)
       continue;
     BasicBlock *parent = inst->getParent();
     if (parent && loop->contains(parent)) {
+      if (DEBUG) {
+        std::cout << "  Hoisting " << inst->getName() << " from " << parent->getName() 
+                  << " to preheader " << preheader->getName() << std::endl;
+      }
       auto sourcePos = parent->findInstIterator(inst);
       auto targetPos = preheader->terminator();
       parent->moveInst(sourcePos, targetPos, preheader);
       changed = true;
     }
   }
+  
+  if (DEBUG && changed) {
+    std::cout << "LICM: Successfully hoisted " << sorted.size() << " invariant instructions" << std::endl;
+  }
+  
   return changed;
 }
 // ---- LICM Pass Implementation ----

src/midend/Pass/Pass.cpp

@@ -10,11 +10,14 @@
 #include "DCE.h"
 #include "Mem2Reg.h"
 #include "Reg2Mem.h"
+#include "GVN.h"
 #include "SCCP.h"
 #include "BuildCFG.h"
 #include "LargeArrayToGlobal.h"
 #include "LoopNormalization.h"
 #include "LICM.h"
+#include "LoopStrengthReduction.h"
+#include "InductionVariableElimination.h"
 #include "Pass.h"
 #include <iostream>
 #include <queue>
@@ -57,6 +60,8 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
     // 注册优化遍
     registerOptimizationPass<BuildCFG>();
     registerOptimizationPass<LargeArrayToGlobalPass>();
+
+    registerOptimizationPass<GVN>();
     
     registerOptimizationPass<SysYDelInstAfterBrPass>();
     registerOptimizationPass<SysYDelNoPreBLockPass>();
@@ -70,6 +75,8 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
     registerOptimizationPass<Mem2Reg>(builderIR);
     registerOptimizationPass<LoopNormalizationPass>(builderIR);
     registerOptimizationPass<LICM>(builderIR);
+    registerOptimizationPass<LoopStrengthReduction>(builderIR);
+    registerOptimizationPass<InductionVariableElimination>();
     registerOptimizationPass<Reg2Mem>(builderIR);
 
     registerOptimizationPass<SCCP>(builderIR);
@@ -125,6 +132,15 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
         printPasses();
       }
 
+      this->clearPasses();
+      this->addPass(&GVN::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After GVN Optimizations ===\n";
+        printPasses();
+      }
+
       this->clearPasses();
       this->addPass(&SCCP::ID);
       this->run();
@@ -136,17 +152,36 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
 
       this->clearPasses();
       this->addPass(&LoopNormalizationPass::ID);
+      this->addPass(&InductionVariableElimination::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After Loop Normalization, Induction Variable Elimination ===\n";
+        printPasses();
+      }
+      
+
+      this->clearPasses();
       this->addPass(&LICM::ID);
       this->run();
 
       if(DEBUG) {
-        std::cout << "=== IR After Loop Normalization and LICM Optimizations ===\n";
+        std::cout << "=== IR After LICM ===\n";
+        printPasses();
+      }
+      
+      this->clearPasses();
+      this->addPass(&LoopStrengthReduction::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After Loop Normalization, and Strength Reduction Optimizations ===\n";
         printPasses();
       }
 
-      this->clearPasses();
-      this->addPass(&Reg2Mem::ID);
-      this->run();
+      // this->clearPasses();
+      // this->addPass(&Reg2Mem::ID);
+      // this->run();
 
       if(DEBUG) {
         std::cout << "=== IR After Reg2Mem Optimizations ===\n";

src/midend/SysYIRPrinter.cpp

@@ -240,7 +240,9 @@ void SysYPrinter::printInst(Instruction *pInst) {
     case Kind::kMul:
     case Kind::kDiv:
     case Kind::kRem:
-    case Kind::kSRA:
+    case Kind::kSrl:
+    case Kind::kSll:
+    case Kind::kSra:
     case Kind::kMulh:
     case Kind::kFAdd:
     case Kind::kFSub:
@@ -274,7 +276,9 @@ void SysYPrinter::printInst(Instruction *pInst) {
         case Kind::kMul: std::cout << "mul"; break;
         case Kind::kDiv: std::cout << "sdiv"; break;
         case Kind::kRem: std::cout << "srem"; break;
-        case Kind::kSRA: std::cout << "ashr"; break;
+        case Kind::kSrl: std::cout << "lshr"; break;
+        case Kind::kSll: std::cout << "shl"; break;
+        case Kind::kSra: std::cout << "ashr"; break;
         case Kind::kMulh: std::cout << "mulh"; break;
         case Kind::kFAdd: std::cout << "fadd"; break;
         case Kind::kFSub: std::cout << "fsub"; break;

src/sysyc.cpp

@@ -35,7 +35,7 @@ void usage(int code) {
                     "Supported options:\n"
                     "  -h \tprint help message and exit\n"
                     "  -f \tpretty-format the input file\n"
-                    "  -s {ast,ir,asm,llvmir,asmd,ird}\tstop after generating AST/IR/Assembly\n"
+                    "  -s {ast,ir,asm,asmd,ird}\tstop after generating AST/IR/Assembly\n"
                     "  -S \tcompile to assembly (.s file)\n"
                     "  -o <file>\tplace the output into <file>\n"
                     "  -O<level>\tenable optimization at <level> (e.g., -O0, -O1)\n";