[midend-tco]修复命名重复问题

Pass_ID_List.md

@@ -396,9 +396,25 @@ check_initial_overflow()
 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/Optimize/Peephole.cpp

@@ -634,6 +634,22 @@ void PeepholeOptimizer::runOnMachineFunction(MachineFunction *mfunc) {
           }
         }
       }
+      // 8. 消除无用移动指令: mv a, a -> (删除)
+      else if (mi1->getOpcode() == RVOpcodes::MV &&
+               mi1->getOperands().size() == 2) {
+        if (mi1->getOperands()[0]->getKind() == MachineOperand::KIND_REG &&
+            mi1->getOperands()[1]->getKind() == MachineOperand::KIND_REG) {
+          auto *dst = static_cast<RegOperand *>(mi1->getOperands()[0].get());
+          auto *src = static_cast<RegOperand *>(mi1->getOperands()[1].get());
+          
+          // 检查源和目标寄存器是否相同
+          if (areRegsEqual(dst, src)) {
+            // 删除这条无用指令
+            instrs.erase(instrs.begin() + i);
+            changed = true;
+          }
+        }
+      }
 
       // 根据是否发生变化调整遍历索引
       if (!changed) {

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

@@ -350,7 +350,11 @@ private:
     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/GlobalStrengthReduction.h

@@ -0,0 +1,107 @@
+#pragma once
+
+#include "Pass.h"
+#include "IR.h"
+#include "SideEffectAnalysis.h"
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+#include <cstdint>
+
+namespace sysy {
+
+// 魔数乘法结构，用于除法优化
+struct MagicNumber {
+    uint32_t multiplier;
+    int shift;
+    bool needAdd;
+    
+    MagicNumber(uint32_t m, int s, bool add = false) 
+        : multiplier(m), shift(s), needAdd(add) {}
+};
+
+// 全局强度削弱优化遍的核心逻辑封装类
+class GlobalStrengthReductionContext {
+public:
+    // 构造函数，接受IRBuilder参数
+    explicit GlobalStrengthReductionContext(IRBuilder* builder) : builder(builder) {}
+    
+    // 运行优化的主要方法
+    void run(Function* func, AnalysisManager* AM, bool& changed);
+
+private:
+    IRBuilder* builder;  // IR构建器
+    
+    // 分析结果
+    SideEffectAnalysisResult* sideEffectAnalysis = nullptr;
+    
+    // 优化计数
+    int algebraicOptCount = 0;
+    int strengthReductionCount = 0;
+    int divisionOptCount = 0;
+    
+    // 主要优化方法
+    bool processBasicBlock(BasicBlock* bb);
+    bool processInstruction(Instruction* inst);
+    
+    // 代数优化方法
+    bool tryAlgebraicOptimization(Instruction* inst);
+    bool optimizeAddition(BinaryInst* inst);
+    bool optimizeSubtraction(BinaryInst* inst);
+    bool optimizeMultiplication(BinaryInst* inst);
+    bool optimizeDivision(BinaryInst* inst);
+    bool optimizeComparison(BinaryInst* inst);
+    bool optimizeLogical(BinaryInst* inst);
+    
+    // 强度削弱方法
+    bool tryStrengthReduction(Instruction* inst);
+    bool reduceMultiplication(BinaryInst* inst);
+    bool reduceDivision(BinaryInst* inst);
+    bool reducePower(CallInst* inst);
+    
+    // 复杂乘法强度削弱方法
+    bool tryComplexMultiplication(BinaryInst* inst, Value* variable, int constant);
+    bool findOptimalShiftDecomposition(int constant, std::vector<int>& shifts);
+    Value* createShiftDecomposition(BinaryInst* inst, Value* variable, const std::vector<int>& shifts);
+    
+    // 魔数乘法相关方法
+    MagicNumber computeMagicNumber(uint32_t divisor);
+    std::pair<int, int> computeMulhMagicNumbers(int divisor);
+    Value* createMagicDivision(BinaryInst* divInst, uint32_t divisor, const MagicNumber& magic);
+    Value* createMagicDivisionLibdivide(BinaryInst* divInst, int divisor);
+    bool isPowerOfTwo(uint32_t n);
+    int log2OfPowerOfTwo(uint32_t n);
+    
+    // 辅助方法
+    bool isConstantInt(Value* val, int& constVal);
+    bool isConstantInt(Value* val, uint32_t& constVal);
+    ConstantInteger* getConstantInt(int val);
+    bool hasOnlyLocalUses(Instruction* inst);
+    void replaceWithOptimized(Instruction* original, Value* replacement);
+};
+
+// 全局强度削弱优化遍类
+class GlobalStrengthReduction : public OptimizationPass {
+private:
+    IRBuilder* builder;  // IR构建器，用于创建新指令
+
+public:
+    // 静态成员，作为该遍的唯一ID
+    static void* ID;
+    
+    // 构造函数，接受IRBuilder参数
+    explicit GlobalStrengthReduction(IRBuilder* builder) 
+        : OptimizationPass("GlobalStrengthReduction", Granularity::Function), builder(builder) {}
+    
+    // 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

@@ -6,6 +6,7 @@
 #include "Loop.h"
 #include "Dom.h"
 #include "SideEffectAnalysis.h"
+#include "AliasAnalysis.h"
 #include <vector>
 #include <unordered_map>
 #include <unordered_set>
@@ -53,6 +54,7 @@ private:
   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;
@@ -90,12 +92,105 @@ private:
   isDeadInductionVariable(const InductionVarInfo* iv, Loop* loop);
   
   /**
-   * 检查归纳变量是否只用于自身更新
+   * 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 是否只用于自身更新
+   * @return phi指令是否可以安全删除
    */
-  bool isUsedOnlyForSelfUpdate(PhiInst* phiInst, Loop* loop);
+  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

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

@@ -127,13 +127,6 @@ private:
    */
   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

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

@@ -107,6 +107,190 @@ public:
     // 所以当AllocaInst的basetype是PointerType时（一维数组）或者是指向ArrayType的PointerType（多位数组）时，返回true
     return aval && (baseType->isPointer() || baseType->as<PointerType>()->getBaseType()->isArray());
   }
+
+  
+  //该实现参考了libdivide的算法
+  static std::pair<int, int> computeMulhMagicNumbers(int divisor) {
+    
+    if (DEBUG) {
+      std::cout << "\n[SR] ===== Computing magic numbers for divisor " << divisor << " (libdivide algorithm) =====" << std::endl;
+    }
+    
+    if (divisor == 0) {
+      if (DEBUG) std::cout << "[SR] Error: divisor must be != 0" << std::endl;
+      return {-1, -1};
+    }
+
+    // libdivide 常数
+    const uint8_t LIBDIVIDE_ADD_MARKER = 0x40;
+    const uint8_t LIBDIVIDE_NEGATIVE_DIVISOR = 0x80;
+    
+    // 辅助函数：计算前导零个数
+    auto count_leading_zeros32 = [](uint32_t val) -> uint32_t {
+      if (val == 0) return 32;
+      return __builtin_clz(val);
+    };
+    
+    // 辅助函数：64位除法返回32位商和余数
+    auto div_64_32 = [](uint32_t high, uint32_t low, uint32_t divisor, uint32_t* rem) -> uint32_t {
+      uint64_t dividend = ((uint64_t)high << 32) | low;
+      uint32_t quotient = dividend / divisor;
+      *rem = dividend % divisor;
+      return quotient;
+    };
+
+    if (DEBUG) {
+      std::cout << "[SR] Input divisor: " << divisor << std::endl;
+    }
+
+    // libdivide_internal_s32_gen 算法实现
+    int32_t d = divisor;
+    uint32_t ud = (uint32_t)d;
+    uint32_t absD = (d < 0) ? -ud : ud;
+    
+    if (DEBUG) {
+      std::cout << "[SR] absD = " << absD << std::endl;
+    }
+    
+    uint32_t floor_log_2_d = 31 - count_leading_zeros32(absD);
+    
+    if (DEBUG) {
+      std::cout << "[SR] floor_log_2_d = " << floor_log_2_d << std::endl;
+    }
+    
+    // 检查 absD 是否为2的幂
+    if ((absD & (absD - 1)) == 0) {
+      if (DEBUG) {
+        std::cout << "[SR] " << absD << " 是2的幂，使用移位方法" << std::endl;
+      }
+      
+      // 对于2的幂，我们只使用移位，不需要魔数
+      int shift = floor_log_2_d;
+      if (d < 0) shift |= 0x80; // 标记负数
+      
+      if (DEBUG) {
+        std::cout << "[SR] Power of 2 result: magic=0, shift=" << shift << std::endl;
+        std::cout << "[SR] ===== End magic computation =====" << std::endl;
+      }
+      
+      // 对于我们的目的，我们将在IR生成中以不同方式处理2的幂
+      // 返回特殊标记
+      return {0, shift};
+    }
+    
+    if (DEBUG) {
+      std::cout << "[SR] " << absD << " is not a power of 2, computing magic number" << std::endl;
+    }
+    
+    // 非2的幂除数的魔数计算
+    uint8_t more;
+    uint32_t rem, proposed_m;
+    
+    // 计算 proposed_m = floor(2^(floor_log_2_d + 31) / absD)
+    proposed_m = div_64_32((uint32_t)1 << (floor_log_2_d - 1), 0, absD, &rem);
+    const uint32_t e = absD - rem;
+    
+    if (DEBUG) {
+      std::cout << "[SR] proposed_m = " << proposed_m << ", rem = " << rem << ", e = " << e << std::endl;
+    }
+    
+    // 确定是否需要"加法"版本
+    const bool branchfree = false; // 使用分支版本
+    
+    if (!branchfree && e < ((uint32_t)1 << floor_log_2_d)) {
+      // 这个幂次有效
+      more = (uint8_t)(floor_log_2_d - 1);
+      if (DEBUG) {
+        std::cout << "[SR] Using basic algorithm, shift = " << (int)more << std::endl;
+      }
+    } else {
+      // 我们需要上升一个等级
+      proposed_m += proposed_m;
+      const uint32_t twice_rem = rem + rem;
+      if (twice_rem >= absD || twice_rem < rem) {
+        proposed_m += 1;
+      }
+      more = (uint8_t)(floor_log_2_d | LIBDIVIDE_ADD_MARKER);
+      if (DEBUG) {
+        std::cout << "[SR] Using add algorithm, proposed_m = " << proposed_m << ", more = " << (int)more << std::endl;
+      }
+    }
+    
+    proposed_m += 1;
+    int32_t magic = (int32_t)proposed_m;
+    
+    // 处理负除数
+    if (d < 0) {
+      more |= LIBDIVIDE_NEGATIVE_DIVISOR;
+      if (!branchfree) {
+        magic = -magic;
+      }
+      if (DEBUG) {
+        std::cout << "[SR] Negative divisor, magic = " << magic << ", more = " << (int)more << std::endl;
+      }
+    }
+    
+    // 为我们的IR生成提取移位量和标志  
+    int shift = more & 0x3F; // 移除标志，保留移位量（位0-5）
+    bool need_add = (more & LIBDIVIDE_ADD_MARKER) != 0;
+    bool is_negative = (more & LIBDIVIDE_NEGATIVE_DIVISOR) != 0;
+    
+    if (DEBUG) {
+      std::cout << "[SR] Final result: magic = " << magic << ", more = " << (int)more 
+                << " (0x" << std::hex << (int)more << std::dec << ")" << std::endl;
+      std::cout << "[SR] Shift = " << shift << ", need_add = " << need_add 
+                << ", is_negative = " << is_negative << std::endl;
+      
+      // Test the magic number using the correct libdivide algorithm
+      std::cout << "[SR] Testing magic number (libdivide algorithm):" << std::endl;
+      int test_values[] = {1, 7, 37, 100, 999, -1, -7, -37, -100};
+      
+      for (int test_val : test_values) {
+        int64_t quotient;
+        
+        // 实现正确的libdivide算法
+        int64_t product = (int64_t)test_val * magic;
+        int64_t high_bits = product >> 32;
+        
+        if (need_add) {
+          // ADD_MARKER情况：移位前加上被除数
+          // 这是libdivide的关键洞察！
+          high_bits += test_val;
+          quotient = high_bits >> shift;
+        } else {
+          // 正常情况：只是移位
+          quotient = high_bits >> shift;
+        }
+        
+        // 符号修正：这是libdivide有符号除法的关键部分！
+        // 如果被除数为负，商需要加1来匹配C语言的截断除法语义
+        if (test_val < 0) {
+          quotient += 1;
+        }
+        
+        int expected = test_val / divisor;
+        
+        bool correct = (quotient == expected);
+        std::cout << "[SR]   " << test_val << " / " << divisor << " = " << quotient 
+                  << " (expected " << expected << ") " << (correct ? "✓" : "✗") << std::endl;
+      }
+      
+      std::cout << "[SR] ===== End magic computation =====" << std::endl;
+    }
+    
+    // 返回魔数、移位量，并在移位中编码ADD_MARKER标志
+    // 我们将使用移位的第6位表示ADD_MARKER，第7位表示负数（如果需要）
+    int encoded_shift = shift;
+    if (need_add) {
+      encoded_shift |= 0x40; // 设置第6位表示ADD_MARKER
+      if (DEBUG) {
+        std::cout << "[SR] Encoding ADD_MARKER in shift: " << encoded_shift << std::endl;
+      }
+    }
+    
+    return {magic, encoded_shift};
+  }
+
 };
 
 }// namespace sysy

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

@@ -0,0 +1,39 @@
+#pragma once
+
+#include "Pass.h"
+#include "Dom.h"
+#include "Loop.h"
+
+namespace sysy {
+
+/**
+ * @class TailCallOpt
+ * @brief 优化尾调用的中端优化通道。
+ *
+ * 该类实现了一个针对函数级别的尾调用优化的优化通道（OptimizationPass）。
+ * 通过分析和转换 IR（中间表示），将可优化的尾调用转换为更高效的形式，
+ * 以减少函数调用的开销，提升程序性能。
+ *
+ * @note 需要传入 IRBuilder 指针用于 IR 构建和修改。
+ *
+ * @method runOnFunction
+ * 对指定函数进行尾调用优化。
+ *
+ * @method getPassID
+ * 获取当前优化通道的唯一标识符。
+ *
+ * @method getAnalysisUsage
+ * 指定该优化通道所依赖和失效的分析集合。
+ */
+class TailCallOpt : public OptimizationPass {
+private:
+  IRBuilder* builder;
+public:
+  TailCallOpt(IRBuilder* builder) : OptimizationPass("TailCallOpt", Granularity::Function), builder(builder) {}
+  static void *ID;
+  bool runOnFunction(Function *F, AnalysisManager &AM) override;
+  void *getPassID() const override { return &ID; }
+  void getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const override;
+};
+
+} // namespace sysy

src/midend/CMakeLists.txt

@@ -15,14 +15,17 @@ 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/GlobalStrengthReduction.cpp
     Pass/Optimize/BuildCFG.cpp
     Pass/Optimize/LargeArrayToGlobal.cpp
+    Pass/Optimize/TailCallOpt.cpp
 )
 
 # 包含中端模块所需的头文件路径

src/midend/IR.cpp

@@ -847,7 +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());
@@ -886,7 +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

@@ -776,38 +776,324 @@ void LoopCharacteristicsPass::findDerivedInductionVars(
   }
 }
 
-// 递归/推进式判定
-bool LoopCharacteristicsPass::isClassicLoopInvariant(Value* val, Loop* loop, const std::unordered_set<Value*>& invariants) {
-  // 1. 常量
-  if (auto* constval = dynamic_cast<ConstantValue*>(val)) 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;
-
-  // 3. 指令且定义在循环外
-  if (auto* inst = dynamic_cast<Instruction*>(val)) {
-    if (!loop->contains(inst->getParent()))
-      return true;
-
-    // 4. 跳转 phi指令 副作用 不外提
-    if (inst->isTerminator() || inst->isPhi() || sideEffectAnalysis->hasSideEffect(inst))
+// 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;
-
-    // 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;
   }
-  // 其它情况
+  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;
 }
 
-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
+// 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)) {
+    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
+  // 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 (DEBUG >= 2) std::cout << "    -> Defined outside loop: YES" << std::endl;
+      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;
+}
+
+
 } // 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/GlobalStrengthReduction.cpp

@@ -0,0 +1,897 @@
+#include "GlobalStrengthReduction.h"
+#include "SysYIROptUtils.h"
+#include "IRBuilder.h"
+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <cmath>
+
+extern int DEBUG;
+
+namespace sysy {
+
+// 全局强度削弱优化遍的静态 ID
+void *GlobalStrengthReduction::ID = (void *)&GlobalStrengthReduction::ID;
+
+// ======================================================================
+// GlobalStrengthReduction 类的实现
+// ======================================================================
+
+bool GlobalStrengthReduction::runOnFunction(Function *func, AnalysisManager &AM) {
+  if (func->getBasicBlocks().empty()) {
+    return false;
+  }
+
+  if (DEBUG) {
+    std::cout << "\n=== Running GlobalStrengthReduction on function: " << func->getName() << " ===" << std::endl;
+  }
+
+  bool changed = false;
+  GlobalStrengthReductionContext context(builder);
+  context.run(func, &AM, changed);
+
+  if (DEBUG) {
+    if (changed) {
+      std::cout << "GlobalStrengthReduction: Function " << func->getName() << " was modified" << std::endl;
+    } else {
+      std::cout << "GlobalStrengthReduction: Function " << func->getName() << " was not modified" << std::endl;
+    }
+    std::cout << "=== GlobalStrengthReduction completed for function: " << func->getName() << " ===" << std::endl;
+  }
+
+  return changed;
+}
+
+void GlobalStrengthReduction::getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const {
+  // 强度削弱依赖副作用分析来判断指令是否可以安全优化
+  analysisDependencies.insert(&SysYSideEffectAnalysisPass::ID);
+  
+  // 强度削弱不会使分析失效，因为：
+  // - 只替换计算指令，不改变控制流
+  // - 不修改内存，不影响别名分析
+  // - 保持程序语义不变
+  // analysisInvalidations 保持为空
+  
+  if (DEBUG) {
+    std::cout << "GlobalStrengthReduction: Declared analysis dependencies (SideEffectAnalysis)" << std::endl;
+  }
+}
+
+// ======================================================================
+// GlobalStrengthReductionContext 类的实现
+// ======================================================================
+
+void GlobalStrengthReductionContext::run(Function *func, AnalysisManager *AM, bool &changed) {
+  if (DEBUG) {
+    std::cout << "  Starting GlobalStrengthReduction analysis for function: " << func->getName() << std::endl;
+  }
+
+  // 获取分析结果
+  if (AM) {
+    sideEffectAnalysis = AM->getAnalysisResult<SideEffectAnalysisResult, SysYSideEffectAnalysisPass>();
+    
+    if (DEBUG) {
+      if (sideEffectAnalysis) {
+        std::cout << "    GlobalStrengthReduction: Using side effect analysis" << std::endl;
+      } else {
+        std::cout << "    GlobalStrengthReduction: Warning - side effect analysis not available" << std::endl;
+      }
+    }
+  }
+
+  // 重置计数器
+  algebraicOptCount = 0;
+  strengthReductionCount = 0;
+  divisionOptCount = 0;
+
+  // 遍历所有基本块进行优化
+  for (auto &bb_ptr : func->getBasicBlocks()) {
+    if (processBasicBlock(bb_ptr.get())) {
+      changed = true;
+    }
+  }
+
+  if (DEBUG) {
+    std::cout << "  GlobalStrengthReduction completed for function: " << func->getName() << std::endl;
+    std::cout << "    Algebraic optimizations: " << algebraicOptCount << std::endl;
+    std::cout << "    Strength reductions: " << strengthReductionCount << std::endl;
+    std::cout << "    Division optimizations: " << divisionOptCount << std::endl;
+  }
+}
+
+bool GlobalStrengthReductionContext::processBasicBlock(BasicBlock *bb) {
+  bool changed = false;
+  
+  if (DEBUG) {
+    std::cout << "    Processing block: " << bb->getName() << std::endl;
+  }
+
+  // 收集需要处理的指令（避免迭代器失效）
+  std::vector<Instruction*> instructions;
+  for (auto &inst_ptr : bb->getInstructions()) {
+    instructions.push_back(inst_ptr.get());
+  }
+
+  // 处理每条指令
+  for (auto inst : instructions) {
+    if (processInstruction(inst)) {
+      changed = true;
+    }
+  }
+
+  return changed;
+}
+
+bool GlobalStrengthReductionContext::processInstruction(Instruction *inst) {
+
+  if (DEBUG) {
+    std::cout << "      Processing instruction: " << inst->getName() << std::endl;
+  }
+
+  // 先尝试代数优化
+  if (tryAlgebraicOptimization(inst)) {
+    algebraicOptCount++;
+    return true;
+  }
+
+  // 再尝试强度削弱
+  if (tryStrengthReduction(inst)) {
+    strengthReductionCount++;
+    return true;
+  }
+
+  return false;
+}
+
+// ======================================================================
+// 代数优化方法
+// ======================================================================
+
+bool GlobalStrengthReductionContext::tryAlgebraicOptimization(Instruction *inst) {
+  auto binary = dynamic_cast<BinaryInst*>(inst);
+  if (!binary) {
+    return false;
+  }
+
+  switch (binary->getKind()) {
+    case Instruction::kAdd:
+      return optimizeAddition(binary);
+    case Instruction::kSub:
+      return optimizeSubtraction(binary);
+    case Instruction::kMul:
+      return optimizeMultiplication(binary);
+    case Instruction::kDiv:
+      return optimizeDivision(binary);
+    case Instruction::kICmpEQ:
+    case Instruction::kICmpNE:
+    case Instruction::kICmpLT:
+    case Instruction::kICmpGT:
+    case Instruction::kICmpLE:
+    case Instruction::kICmpGE:
+      return optimizeComparison(binary);
+    case Instruction::kAnd:
+    case Instruction::kOr:
+      return optimizeLogical(binary);
+    default:
+      return false;
+  }
+}
+
+bool GlobalStrengthReductionContext::optimizeAddition(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  // x + 0 = x
+  if (isConstantInt(rhs, constVal) && constVal == 0) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x + 0 -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, lhs);
+    return true;
+  }
+  
+  // 0 + x = x
+  if (isConstantInt(lhs, constVal) && constVal == 0) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = 0 + x -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, rhs);
+    return true;
+  }
+
+  // x + (-y) = x - y
+  if (auto rhsInst = dynamic_cast<UnaryInst*>(rhs)) {
+    if (rhsInst->getKind() == Instruction::kNeg) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x + (-y) -> x - y" << std::endl;
+      }
+      // 创建减法指令
+      builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+      auto subInst = builder->createSubInst(lhs, rhsInst->getOperand());
+      replaceWithOptimized(inst, subInst);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::optimizeSubtraction(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  // x - 0 = x
+  if (isConstantInt(rhs, constVal) && constVal == 0) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x - 0 -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, lhs);
+    return true;
+  }
+
+  // x - x = 0 (如果x没有副作用)
+  if (lhs == rhs && hasOnlyLocalUses(dynamic_cast<Instruction*>(lhs))) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x - x -> 0" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(0));
+    return true;
+  }
+
+  // x - (-y) = x + y
+  if (auto rhsInst = dynamic_cast<UnaryInst*>(rhs)) {
+    if (rhsInst->getKind() == Instruction::kNeg) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x - (-y) -> x + y" << std::endl;
+      }
+      builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+      auto addInst = builder->createAddInst(lhs, rhsInst->getOperand());
+      replaceWithOptimized(inst, addInst);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::optimizeMultiplication(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  // x * 0 = 0
+  if (isConstantInt(rhs, constVal) && constVal == 0) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x * 0 -> 0" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(0));
+    return true;
+  }
+  
+  // 0 * x = 0
+  if (isConstantInt(lhs, constVal) && constVal == 0) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = 0 * x -> 0" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(0));
+    return true;
+  }
+
+  // x * 1 = x
+  if (isConstantInt(rhs, constVal) && constVal == 1) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x * 1 -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, lhs);
+    return true;
+  }
+  
+  // 1 * x = x
+  if (isConstantInt(lhs, constVal) && constVal == 1) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = 1 * x -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, rhs);
+    return true;
+  }
+
+  // x * (-1) = -x
+  if (isConstantInt(rhs, constVal) && constVal == -1) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x * (-1) -> -x" << std::endl;
+    }
+    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    auto negInst = builder->createNegInst(lhs);
+    replaceWithOptimized(inst, negInst);
+    return true;
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::optimizeDivision(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  // x / 1 = x
+  if (isConstantInt(rhs, constVal) && constVal == 1) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x / 1 -> x" << std::endl;
+    }
+    replaceWithOptimized(inst, lhs);
+    return true;
+  }
+
+  // x / (-1) = -x
+  if (isConstantInt(rhs, constVal) && constVal == -1) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x / (-1) -> -x" << std::endl;
+    }
+    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    auto negInst = builder->createNegInst(lhs);
+    replaceWithOptimized(inst, negInst);
+    return true;
+  }
+
+  // x / x = 1 (如果x != 0且没有副作用)
+  if (lhs == rhs && hasOnlyLocalUses(dynamic_cast<Instruction*>(lhs))) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x / x -> 1" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(1));
+    return true;
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::optimizeComparison(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+
+  // x == x = true (如果x没有副作用)
+  if (inst->getKind() == Instruction::kICmpEQ && lhs == rhs && 
+      hasOnlyLocalUses(dynamic_cast<Instruction*>(lhs))) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x == x -> true" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(1));
+    return true;
+  }
+
+  // x != x = false (如果x没有副作用)
+  if (inst->getKind() == Instruction::kICmpNE && lhs == rhs && 
+      hasOnlyLocalUses(dynamic_cast<Instruction*>(lhs))) {
+    if (DEBUG) {
+      std::cout << "        Algebraic: " << inst->getName() << " = x != x -> false" << std::endl;
+    }
+    replaceWithOptimized(inst, getConstantInt(0));
+    return true;
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::optimizeLogical(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  if (inst->getKind() == Instruction::kAnd) {
+    // x && 0 = 0
+    if (isConstantInt(rhs, constVal) && constVal == 0) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x && 0 -> 0" << std::endl;
+      }
+      replaceWithOptimized(inst, getConstantInt(0));
+      return true;
+    }
+    
+    // x && -1 = x
+    if (isConstantInt(rhs, constVal) && constVal == -1) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x && 1 -> x" << std::endl;
+      }
+      replaceWithOptimized(inst, lhs);
+      return true;
+    }
+
+    // x && x = x
+    if (lhs == rhs) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x && x -> x" << std::endl;
+      }
+      replaceWithOptimized(inst, lhs);
+      return true;
+    }
+  } else if (inst->getKind() == Instruction::kOr) {
+    // x || 0 = x
+    if (isConstantInt(rhs, constVal) && constVal == 0) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x || 0 -> x" << std::endl;
+      }
+      replaceWithOptimized(inst, lhs);
+      return true;
+    }
+
+    // x || x = x
+    if (lhs == rhs) {
+      if (DEBUG) {
+        std::cout << "        Algebraic: " << inst->getName() << " = x || x -> x" << std::endl;
+      }
+      replaceWithOptimized(inst, lhs);
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// ======================================================================
+// 强度削弱方法
+// ======================================================================
+
+bool GlobalStrengthReductionContext::tryStrengthReduction(Instruction *inst) {
+  if (auto binary = dynamic_cast<BinaryInst*>(inst)) {
+    switch (binary->getKind()) {
+      case Instruction::kMul:
+        return reduceMultiplication(binary);
+      case Instruction::kDiv:
+        return reduceDivision(binary);
+      default:
+        return false;
+    }
+  } else if (auto call = dynamic_cast<CallInst*>(inst)) {
+    return reducePower(call);
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::reduceMultiplication(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  int constVal;
+
+  // 尝试右操作数为常数
+  Value* variable = lhs;
+  if (isConstantInt(rhs, constVal) && constVal > 0) {
+    return tryComplexMultiplication(inst, variable, constVal);
+  }
+  
+  // 尝试左操作数为常数
+  if (isConstantInt(lhs, constVal) && constVal > 0) {
+    variable = rhs;
+    return tryComplexMultiplication(inst, variable, constVal);
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::tryComplexMultiplication(BinaryInst* inst, Value* variable, int constant) {
+  // 首先检查是否为2的幂，使用简单位移
+  if (isPowerOfTwo(constant)) {
+    int shiftAmount = log2OfPowerOfTwo(constant);
+    if (DEBUG) {
+      std::cout << "        StrengthReduction: " << inst->getName() 
+                << " = x * " << constant << " -> x << " << shiftAmount << std::endl;
+    }
+    
+    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    auto shiftInst = builder->createBinaryInst(Instruction::kSll, Type::getIntType(), variable, getConstantInt(shiftAmount));
+    replaceWithOptimized(inst, shiftInst);
+    return true;
+  }
+  
+  // 尝试分解为位移和加法的组合
+  std::vector<int> shifts;
+  if (findOptimalShiftDecomposition(constant, shifts)) {
+    if (DEBUG) {
+      std::cout << "        StrengthReduction: " << inst->getName() 
+                << " = x * " << constant << " -> shift decomposition with " << shifts.size() << " terms" << std::endl;
+    }
+    
+    Value* result = createShiftDecomposition(inst, variable, shifts);
+    if (result) {
+      replaceWithOptimized(inst, result);
+      return true;
+    }
+  }
+  
+  return false;
+}
+
+bool GlobalStrengthReductionContext::findOptimalShiftDecomposition(int constant, std::vector<int>& shifts) {
+  shifts.clear();
+  
+  // 常见的有效分解模式
+  switch (constant) {
+    case 3:   // 3 = 2^1 + 2^0 -> (x << 1) + x
+      shifts = {1, 0};
+      return true;
+    case 5:   // 5 = 2^2 + 2^0 -> (x << 2) + x  
+      shifts = {2, 0};
+      return true;
+    case 6:   // 6 = 2^2 + 2^1 -> (x << 2) + (x << 1)
+      shifts = {2, 1};
+      return true;
+    case 7:   // 7 = 2^2 + 2^1 + 2^0 -> (x << 2) + (x << 1) + x
+      shifts = {2, 1, 0};
+      return true;
+    case 9:   // 9 = 2^3 + 2^0 -> (x << 3) + x
+      shifts = {3, 0};
+      return true;
+    case 10:  // 10 = 2^3 + 2^1 -> (x << 3) + (x << 1)
+      shifts = {3, 1};
+      return true;
+    case 11:  // 11 = 2^3 + 2^1 + 2^0 -> (x << 3) + (x << 1) + x
+      shifts = {3, 1, 0};
+      return true;
+    case 12:  // 12 = 2^3 + 2^2 -> (x << 3) + (x << 2)
+      shifts = {3, 2};
+      return true;
+    case 13:  // 13 = 2^3 + 2^2 + 2^0 -> (x << 3) + (x << 2) + x
+      shifts = {3, 2, 0};
+      return true;
+    case 14:  // 14 = 2^3 + 2^2 + 2^1 -> (x << 3) + (x << 2) + (x << 1)
+      shifts = {3, 2, 1};
+      return true;
+    case 15:  // 15 = 2^3 + 2^2 + 2^1 + 2^0 -> (x << 3) + (x << 2) + (x << 1) + x
+      shifts = {3, 2, 1, 0};
+      return true;
+    case 17:  // 17 = 2^4 + 2^0 -> (x << 4) + x
+      shifts = {4, 0};
+      return true;
+    case 18:  // 18 = 2^4 + 2^1 -> (x << 4) + (x << 1)
+      shifts = {4, 1};
+      return true;
+    case 20:  // 20 = 2^4 + 2^2 -> (x << 4) + (x << 2)
+      shifts = {4, 2};
+      return true;
+    case 24:  // 24 = 2^4 + 2^3 -> (x << 4) + (x << 3)
+      shifts = {4, 3};
+      return true;
+    case 25:  // 25 = 2^4 + 2^3 + 2^0 -> (x << 4) + (x << 3) + x
+      shifts = {4, 3, 0};
+      return true;
+    case 100: // 100 = 2^6 + 2^5 + 2^2 -> (x << 6) + (x << 5) + (x << 2)
+      shifts = {6, 5, 2};
+      return true;
+  }
+  
+  // 通用二进制分解（最多4个项，避免过度复杂化）
+  if (constant > 0 && constant < 256) {
+    std::vector<int> binaryShifts;
+    int temp = constant;
+    int bit = 0;
+    
+    while (temp > 0 && binaryShifts.size() < 4) {
+      if (temp & 1) {
+        binaryShifts.push_back(bit);
+      }
+      temp >>= 1;
+      bit++;
+    }
+    
+    // 只有当项数不超过3个时才使用二进制分解（比直接乘法更有效）
+    if (binaryShifts.size() <= 3 && binaryShifts.size() >= 2) {
+      shifts = binaryShifts;
+      return true;
+    }
+  }
+  
+  return false;
+}
+
+Value* GlobalStrengthReductionContext::createShiftDecomposition(BinaryInst* inst, Value* variable, const std::vector<int>& shifts) {
+  if (shifts.empty()) return nullptr;
+  
+  builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+  
+  Value* result = nullptr;
+  
+  for (int shift : shifts) {
+    Value* term;
+    if (shift == 0) {
+      // 0位移就是原变量
+      term = variable;
+    } else {
+      // 创建位移指令
+      term = builder->createBinaryInst(Instruction::kSll, Type::getIntType(), variable, getConstantInt(shift));
+    }
+    
+    if (result == nullptr) {
+      result = term;
+    } else {
+      // 累加到结果中
+      result = builder->createAddInst(result, term);
+    }
+  }
+  
+  return result;
+}
+
+bool GlobalStrengthReductionContext::reduceDivision(BinaryInst *inst) {
+  Value *lhs = inst->getLhs();
+  Value *rhs = inst->getRhs();
+  uint32_t constVal;
+
+  // x / 2^n = x >> n (对于无符号除法或已知为正数的情况)
+  if (isConstantInt(rhs, constVal) && constVal > 0 && isPowerOfTwo(constVal)) {
+    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    int shiftAmount = log2OfPowerOfTwo(constVal);
+    // 有符号除法校正：(x + (x >> 31) & mask) >> k
+    int maskValue = constVal - 1;
+    
+    // x >> 31 (算术右移获取符号位)
+    Value* signShift = ConstantInteger::get(31);
+    Value* signBits = builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      lhs->getType(),
+      lhs,
+      signShift
+    );
+    
+    // (x >> 31) & mask
+    Value* mask = ConstantInteger::get(maskValue);
+    Value* correction = builder->createBinaryInst(
+      Instruction::Kind::kAnd,
+      lhs->getType(),
+      signBits,
+      mask
+    );
+    
+    // x + correction
+    Value* corrected = builder->createAddInst(lhs, correction);
+    
+    // (x + correction) >> k
+    Value* divShift = ConstantInteger::get(shiftAmount);
+    Value* shiftInst = builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      lhs->getType(),
+      corrected,
+      divShift
+    );
+
+    if (DEBUG) {
+      std::cout << "        StrengthReduction: " << inst->getName() 
+                << " = x / " << constVal << " -> (x + (x >> 31) & mask) >> " << shiftAmount << std::endl;
+    }
+    
+    // builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    // Value* divisor_minus_1 = ConstantInteger::get(constVal - 1);
+    // Value* adjusted = builder->createAddInst(lhs, divisor_minus_1);
+    // Value* shiftInst = builder->createBinaryInst(Instruction::kSra, Type::getIntType(), adjusted, getConstantInt(shiftAmount));
+    replaceWithOptimized(inst, shiftInst);
+    strengthReductionCount++;
+    return true;
+  }
+
+  // x / c = x * magic_number (魔数乘法优化 - 使用libdivide算法)
+  if (isConstantInt(rhs, constVal) && constVal > 1 && constVal != (uint32_t)(-1)) {
+    // auto magicPair = computeMulhMagicNumbers(static_cast<int>(constVal));
+    Value* magicResult = createMagicDivisionLibdivide(inst, static_cast<int>(constVal));
+    replaceWithOptimized(inst, magicResult);
+    divisionOptCount++;
+    return true;
+  }
+
+  return false;
+}
+
+bool GlobalStrengthReductionContext::reducePower(CallInst *inst) {
+  // 检查是否是pow函数调用
+  Function* callee = inst->getCallee();
+  if (!callee || callee->getName() != "pow") {
+    return false;
+  }
+
+  // pow(x, 2) = x * x
+  if (inst->getNumOperands() >= 2) {
+    int exponent;
+    if (isConstantInt(inst->getOperand(1), exponent)) {
+      if (exponent == 2) {
+        if (DEBUG) {
+          std::cout << "        StrengthReduction: pow(x, 2) -> x * x" << std::endl;
+        }
+        
+        Value* base = inst->getOperand(0);
+        builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+        auto mulInst = builder->createMulInst(base, base);
+        replaceWithOptimized(inst, mulInst);
+        strengthReductionCount++;
+        return true;
+      } else if (exponent >= 3 && exponent <= 8) {
+        // 对于小的指数，展开为连续乘法
+        if (DEBUG) {
+          std::cout << "        StrengthReduction: pow(x, " << exponent << ") -> repeated multiplication" << std::endl;
+        }
+        
+        Value* base = inst->getOperand(0);
+        Value* result = base;
+        builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+        
+        for (int i = 1; i < exponent; i++) {
+          result = builder->createMulInst(result, base);
+        }
+        
+        replaceWithOptimized(inst, result);
+        strengthReductionCount++;
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+Value* GlobalStrengthReductionContext::createMagicDivisionLibdivide(BinaryInst* divInst, int divisor) {
+  builder->setPosition(divInst->getParent(), divInst->getParent()->findInstIterator(divInst));
+  // 使用mulh指令优化任意常数除法
+  auto [magic, shift] = SysYIROptUtils::computeMulhMagicNumbers(divisor);
+  
+  // 检查是否无法优化（magic == -1, shift == -1 表示失败）
+  if (magic == -1 && shift == -1) {
+    if (DEBUG) {
+      std::cout << "[SR] Cannot optimize division by " << divisor 
+                << ", keeping original division" << std::endl;
+    }
+    // 返回 nullptr 表示无法优化，调用方应该保持原始除法
+    return nullptr;
+  }
+  
+  // 2的幂次方除法可以用移位优化（但这不是魔数法的情况）这种情况应该不会被分类到这里但是还是做一个保护措施
+  if ((divisor & (divisor - 1)) == 0 && divisor > 0) {
+    // 是2的幂次方，可以用移位
+    int shift_amount = 0;
+    int temp = divisor;
+    while (temp > 1) {
+      temp >>= 1;
+      shift_amount++;
+    }
+    
+    Value* shiftConstant = ConstantInteger::get(shift_amount);
+    // 对于有符号除法，需要先加上除数-1然后再移位（为了正确处理负数舍入）
+    Value* divisor_minus_1 = ConstantInteger::get(divisor - 1);
+    Value* adjusted = builder->createAddInst(divInst->getOperand(0), divisor_minus_1);
+    return builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      divInst->getOperand(0)->getType(),
+      adjusted,
+      shiftConstant
+    );
+  }
+  
+  // 创建魔数常量
+  // 检查魔数是否能放入32位，如果不能，则不进行优化
+  if (magic > INT32_MAX || magic < INT32_MIN) {
+    if (DEBUG) {
+      std::cout << "[SR] Magic number " << magic << " exceeds 32-bit range, skipping optimization" << std::endl;
+    }
+    return nullptr; // 无法优化，保持原始除法
+  }
+  
+  Value* magicConstant = ConstantInteger::get((int32_t)magic);
+  
+  // 检查是否需要ADD_MARKER处理（加法调整）
+  bool needAdd = (shift & 0x40) != 0;
+  int actualShift = shift & 0x3F; // 提取真实的移位量
+  
+  if (DEBUG) {
+    std::cout << "[SR] IR Generation: magic=" << magic << ", needAdd=" << needAdd 
+              << ", actualShift=" << actualShift << std::endl;
+  }
+  
+  // 执行高位乘法：mulh(x, magic)
+  Value* mulhResult = builder->createBinaryInst(
+    Instruction::Kind::kMulh,  // 高位乘法
+    divInst->getOperand(0)->getType(),
+    divInst->getOperand(0),
+    magicConstant
+  );
+  
+  if (needAdd) {
+    // ADD_MARKER 情况：需要在移位前加上被除数
+    // 这对应于 libdivide 的加法调整算法
+    if (DEBUG) {
+      std::cout << "[SR] Applying ADD_MARKER: adding dividend before shift" << std::endl;
+    }
+    mulhResult = builder->createAddInst(mulhResult, divInst->getOperand(0));
+  }
+  
+  if (actualShift > 0) {
+    // 如果需要额外移位
+    Value* shiftConstant = ConstantInteger::get(actualShift);
+    mulhResult = builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      divInst->getOperand(0)->getType(),
+      mulhResult,
+      shiftConstant
+    );
+  }
+  
+  // 标准的有符号除法符号修正：如果被除数为负，商需要加1
+  // 这对所有有符号除法都需要，不管是否可能有负数
+  Value* isNegative = builder->createICmpLTInst(divInst->getOperand(0), ConstantInteger::get(0));
+  // 将i1转换为i32：负数时为1，非负数时为0 ICmpLTInst的结果会默认转化为32位
+  mulhResult = builder->createAddInst(mulhResult, isNegative);
+  
+  return mulhResult; 
+}
+
+// ======================================================================
+// 辅助方法
+// ======================================================================
+
+bool GlobalStrengthReductionContext::isPowerOfTwo(uint32_t n) {
+  return n > 0 && (n & (n - 1)) == 0;
+}
+
+int GlobalStrengthReductionContext::log2OfPowerOfTwo(uint32_t n) {
+  int result = 0;
+  while (n > 1) {
+    n >>= 1;
+    result++;
+  }
+  return result;
+}
+
+bool GlobalStrengthReductionContext::isConstantInt(Value* val, int& constVal) {
+  if (auto constInt = dynamic_cast<ConstantInteger*>(val)) {
+    constVal = std::get<int>(constInt->getVal());
+    return true;
+  }
+  return false;
+}
+
+bool GlobalStrengthReductionContext::isConstantInt(Value* val, uint32_t& constVal) {
+  if (auto constInt = dynamic_cast<ConstantInteger*>(val)) {
+    int signedVal = std::get<int>(constInt->getVal());
+    if (signedVal >= 0) {
+      constVal = static_cast<uint32_t>(signedVal);
+      return true;
+    }
+  }
+  return false;
+}
+
+ConstantInteger* GlobalStrengthReductionContext::getConstantInt(int val) {
+  return ConstantInteger::get(val);
+}
+
+bool GlobalStrengthReductionContext::hasOnlyLocalUses(Instruction* inst) {
+  if (!inst) return true;
+  
+  // 简单检查：如果指令没有副作用，则认为是本地的
+  if (sideEffectAnalysis) {
+    auto sideEffect = sideEffectAnalysis->getInstructionSideEffect(inst);
+    return sideEffect.type == SideEffectType::NO_SIDE_EFFECT;
+  }
+  
+  // 没有副作用分析时，保守处理
+  return !inst->isCall() && !inst->isStore() && !inst->isLoad();
+}
+
+void GlobalStrengthReductionContext::replaceWithOptimized(Instruction* original, Value* replacement) {
+  if (DEBUG) {
+    std::cout << "          Replacing " << original->getName() 
+              << " with " << replacement->getName() << std::endl;
+  }
+  
+  original->replaceAllUsesWith(replacement);
+  
+  // 如果替换值是新创建的指令，确保它有合适的名字
+//   if (auto replInst = dynamic_cast<Instruction*>(replacement)) {
+//     if (replInst->getName().empty()) {
+//       replInst->setName(original->getName() + "_opt");
+//     }
+//   }
+  
+  // 删除原指令，让调用者处理
+  SysYIROptUtils::usedelete(original);
+}
+
+} // namespace sysy

src/midend/Pass/Optimize/InductionVariableElimination.cpp

@@ -3,6 +3,7 @@
 #include "Loop.h"
 #include "Dom.h"
 #include "SideEffectAnalysis.h"
+#include "AliasAnalysis.h"
 #include "SysYIROptUtils.h"
 #include <iostream>
 #include <algorithm>
@@ -43,6 +44,7 @@ void InductionVariableElimination::getAnalysisUsage(std::set<void*>& analysisDep
   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);
@@ -93,6 +95,18 @@ bool InductionVariableEliminationContext::run(Function* F, AnalysisManager& AM)
     }
   }
 
+  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
@@ -179,9 +193,9 @@ InductionVariableEliminationContext::isDeadInductionVariable(const InductionVarI
     return nullptr; // 不是 phi 指令
   }
 
-  // 检查是否只用于自身更新
-  if (!isUsedOnlyForSelfUpdate(phiInst, loop)) {
-    return nullptr; // 有其他用途
+  // 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
@@ -191,9 +205,333 @@ InductionVariableEliminationContext::isDeadInductionVariable(const InductionVarI
   return deadIV;
 }
 
-bool InductionVariableEliminationContext::isUsedOnlyForSelfUpdate(PhiInst* phiInst, Loop* loop) {
-  // 检查 phi 指令的所有使用
-  for (auto use : phiInst->getUses()) {
+// 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);
     
@@ -201,35 +539,180 @@ bool InductionVariableEliminationContext::isUsedOnlyForSelfUpdate(PhiInst* phiIn
       return false; // 被非指令使用
     }
     
-    // 检查使用是否在循环内
     if (!loop->contains(userInst->getParent())) {
       return false; // 在循环外被使用
     }
     
-    // 检查是否为自身的更新指令
-    bool isSelfUpdate = false;
-    
-    // 检查是否为加法/减法指令（常见的归纳变量更新模式）
-    if (userInst->getKind() == Instruction::Kind::kAdd || 
-        userInst->getKind() == Instruction::Kind::kSub) {
-      auto* binInst = dynamic_cast<BinaryInst*>(userInst);
-      if (binInst && (binInst->getOperand(0) == phiInst || binInst->getOperand(1) == phiInst)) {
-        // 检查这个指令的结果是否流回到 phi
-        for (auto& [incomingBB, incomingVal] : phiInst->getIncomingValues()) {
-          if (loop->contains(incomingBB) && incomingVal == binInst) {
-            isSelfUpdate = true;
-            break;
-          }
-        }
-      }
-    }
-    
-    if (!isSelfUpdate) {
-      return false; // 有非自更新的使用
+    // 递归检查使用者
+    if (!isInstructionEffectivelyDead(userInst, loop, maxDepth - 1)) {
+      return false; // 存在有效使用
     }
   }
   
-  return true; // 只用于自身更新
+  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(

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/Optimize/LoopStrengthReduction.cpp

@@ -106,187 +106,6 @@ bool StrengthReductionContext::analyzeInductionVariableRange(
   return hasNegativePotential;
 }
 
-//该实现参考了libdivide的算法
-std::pair<int, int> StrengthReductionContext::computeMulhMagicNumbers(int divisor) const {
-  
-  if (DEBUG) {
-    std::cout << "\n[SR] ===== Computing magic numbers for divisor " << divisor << " (libdivide algorithm) =====" << std::endl;
-  }
-  
-  if (divisor == 0) {
-    if (DEBUG) std::cout << "[SR] Error: divisor must be != 0" << std::endl;
-    return {-1, -1};
-  }
-
-  // libdivide 常数
-  const uint8_t LIBDIVIDE_ADD_MARKER = 0x40;
-  const uint8_t LIBDIVIDE_NEGATIVE_DIVISOR = 0x80;
-  
-  // 辅助函数：计算前导零个数
-  auto count_leading_zeros32 = [](uint32_t val) -> uint32_t {
-    if (val == 0) return 32;
-    return __builtin_clz(val);
-  };
-  
-  // 辅助函数：64位除法返回32位商和余数
-  auto div_64_32 = [](uint32_t high, uint32_t low, uint32_t divisor, uint32_t* rem) -> uint32_t {
-    uint64_t dividend = ((uint64_t)high << 32) | low;
-    uint32_t quotient = dividend / divisor;
-    *rem = dividend % divisor;
-    return quotient;
-  };
-
-  if (DEBUG) {
-    std::cout << "[SR] Input divisor: " << divisor << std::endl;
-  }
-
-  // libdivide_internal_s32_gen 算法实现
-  int32_t d = divisor;
-  uint32_t ud = (uint32_t)d;
-  uint32_t absD = (d < 0) ? -ud : ud;
-  
-  if (DEBUG) {
-    std::cout << "[SR] absD = " << absD << std::endl;
-  }
-  
-  uint32_t floor_log_2_d = 31 - count_leading_zeros32(absD);
-  
-  if (DEBUG) {
-    std::cout << "[SR] floor_log_2_d = " << floor_log_2_d << std::endl;
-  }
-  
-  // 检查 absD 是否为2的幂
-  if ((absD & (absD - 1)) == 0) {
-    if (DEBUG) {
-      std::cout << "[SR] " << absD << " 是2的幂，使用移位方法" << std::endl;
-    }
-    
-    // 对于2的幂，我们只使用移位，不需要魔数
-    int shift = floor_log_2_d;
-    if (d < 0) shift |= 0x80; // 标记负数
-    
-    if (DEBUG) {
-      std::cout << "[SR] Power of 2 result: magic=0, shift=" << shift << std::endl;
-      std::cout << "[SR] ===== End magic computation =====" << std::endl;
-    }
-    
-    // 对于我们的目的，我们将在IR生成中以不同方式处理2的幂
-    // 返回特殊标记
-    return {0, shift};
-  }
-  
-  if (DEBUG) {
-    std::cout << "[SR] " << absD << " is not a power of 2, computing magic number" << std::endl;
-  }
-  
-  // 非2的幂除数的魔数计算
-  uint8_t more;
-  uint32_t rem, proposed_m;
-  
-  // 计算 proposed_m = floor(2^(floor_log_2_d + 31) / absD)
-  proposed_m = div_64_32((uint32_t)1 << (floor_log_2_d - 1), 0, absD, &rem);
-  const uint32_t e = absD - rem;
-  
-  if (DEBUG) {
-    std::cout << "[SR] proposed_m = " << proposed_m << ", rem = " << rem << ", e = " << e << std::endl;
-  }
-  
-  // 确定是否需要"加法"版本
-  const bool branchfree = false; // 使用分支版本
-  
-  if (!branchfree && e < ((uint32_t)1 << floor_log_2_d)) {
-    // 这个幂次有效
-    more = (uint8_t)(floor_log_2_d - 1);
-    if (DEBUG) {
-      std::cout << "[SR] Using basic algorithm, shift = " << (int)more << std::endl;
-    }
-  } else {
-    // 我们需要上升一个等级
-    proposed_m += proposed_m;
-    const uint32_t twice_rem = rem + rem;
-    if (twice_rem >= absD || twice_rem < rem) {
-      proposed_m += 1;
-    }
-    more = (uint8_t)(floor_log_2_d | LIBDIVIDE_ADD_MARKER);
-    if (DEBUG) {
-      std::cout << "[SR] Using add algorithm, proposed_m = " << proposed_m << ", more = " << (int)more << std::endl;
-    }
-  }
-  
-  proposed_m += 1;
-  int32_t magic = (int32_t)proposed_m;
-  
-  // 处理负除数
-  if (d < 0) {
-    more |= LIBDIVIDE_NEGATIVE_DIVISOR;
-    if (!branchfree) {
-      magic = -magic;
-    }
-    if (DEBUG) {
-      std::cout << "[SR] Negative divisor, magic = " << magic << ", more = " << (int)more << std::endl;
-    }
-  }
-  
-  // 为我们的IR生成提取移位量和标志  
-  int shift = more & 0x3F; // 移除标志，保留移位量（位0-5）
-  bool need_add = (more & LIBDIVIDE_ADD_MARKER) != 0;
-  bool is_negative = (more & LIBDIVIDE_NEGATIVE_DIVISOR) != 0;
-  
-  if (DEBUG) {
-    std::cout << "[SR] Final result: magic = " << magic << ", more = " << (int)more 
-              << " (0x" << std::hex << (int)more << std::dec << ")" << std::endl;
-    std::cout << "[SR] Shift = " << shift << ", need_add = " << need_add 
-              << ", is_negative = " << is_negative << std::endl;
-    
-    // Test the magic number using the correct libdivide algorithm
-    std::cout << "[SR] Testing magic number (libdivide algorithm):" << std::endl;
-    int test_values[] = {1, 7, 37, 100, 999, -1, -7, -37, -100};
-    
-    for (int test_val : test_values) {
-      int64_t quotient;
-      
-      // 实现正确的libdivide算法
-      int64_t product = (int64_t)test_val * magic;
-      int64_t high_bits = product >> 32;
-      
-      if (need_add) {
-        // ADD_MARKER情况：移位前加上被除数
-        // 这是libdivide的关键洞察！
-        high_bits += test_val;
-        quotient = high_bits >> shift;
-      } else {
-        // 正常情况：只是移位
-        quotient = high_bits >> shift;
-      }
-      
-      // 符号修正：这是libdivide有符号除法的关键部分！
-      // 如果被除数为负，商需要加1来匹配C语言的截断除法语义
-      if (test_val < 0) {
-        quotient += 1;
-      }
-      
-      int expected = test_val / divisor;
-      
-      bool correct = (quotient == expected);
-      std::cout << "[SR]   " << test_val << " / " << divisor << " = " << quotient 
-                << " (expected " << expected << ") " << (correct ? "✓" : "✗") << std::endl;
-    }
-    
-    std::cout << "[SR] ===== End magic computation =====" << std::endl;
-  }
-  
-  // 返回魔数、移位量，并在移位中编码ADD_MARKER标志
-  // 我们将使用移位的第6位表示ADD_MARKER，第7位表示负数（如果需要）
-  int encoded_shift = shift;
-  if (need_add) {
-    encoded_shift |= 0x40; // 设置第6位表示ADD_MARKER
-    if (DEBUG) {
-      std::cout << "[SR] Encoding ADD_MARKER in shift: " << encoded_shift << std::endl;
-    }
-  }
-  
-  return {magic, encoded_shift};
-}
 
 bool LoopStrengthReduction::runOnFunction(Function* F, AnalysisManager& AM) {
   if (F->getBasicBlocks().empty()) {
@@ -1018,7 +837,7 @@ Value* StrengthReductionContext::generateConstantDivisionReplacement(
   IRBuilder* builder
 ) const {
   // 使用mulh指令优化任意常数除法
-  auto [magic, shift] = computeMulhMagicNumbers(candidate->multiplier);
+  auto [magic, shift] = SysYIROptUtils::computeMulhMagicNumbers(candidate->multiplier);
   
   // 检查是否无法优化（magic == -1, shift == -1 表示失败）
   if (magic == -1 && shift == -1) {

src/midend/Pass/Optimize/TailCallOpt.cpp

@@ -0,0 +1,125 @@
+#include "TailCallOpt.h"
+#include "IR.h"
+#include "IRBuilder.h"
+#include "SysYIROptUtils.h"
+#include <vector>
+// #include <iostream>
+#include <algorithm>
+
+namespace sysy {
+
+void *TailCallOpt::ID = (void *)&TailCallOpt::ID;
+
+void TailCallOpt::getAnalysisUsage(std::set<void *> &analysisDependencies, std::set<void *> &analysisInvalidations) const {
+  analysisInvalidations.insert(&DominatorTreeAnalysisPass::ID);
+  analysisInvalidations.insert(&LoopAnalysisPass::ID);
+}
+
+bool TailCallOpt::runOnFunction(Function *F, AnalysisManager &AM) {
+  std::vector<CallInst *> tailCallInsts;
+  // 遍历函数的所有基本块
+  for (auto &bb_ptr : F->getBasicBlocks()) {
+    auto BB = bb_ptr.get();
+    if (BB->getInstructions().empty()) continue; // 跳过空基本块
+
+    auto term_iter = BB->terminator();
+    if (term_iter == BB->getInstructions().end()) continue; // 没有终结指令则跳过
+    auto term = (*term_iter).get();
+
+    if (!term || !term->isReturn()) continue; // 不是返回指令则跳过
+    auto retInst = static_cast<ReturnInst *>(term);
+
+    Instruction *prevInst = nullptr;
+    if (BB->getInstructions().size() > 1) {
+        auto it = term_iter;
+        --it; // 获取返回指令前的指令
+        prevInst = (*it).get();
+    }
+
+    if (!prevInst || !prevInst->isCall()) continue; // 前一条不是调用指令则跳过
+    auto callInst = static_cast<CallInst *>(prevInst);
+
+    // 检查是否为尾递归调用：被调用函数与当前函数相同且返回值与调用结果匹配
+    if (callInst->getCallee() == F) {
+  // 对于尾递归，返回值应为调用结果或为 void 类型
+        if (retInst->getReturnValue() == callInst || 
+            (retInst->getReturnValue() == nullptr && callInst->getType()->isVoid())) {
+            tailCallInsts.push_back(callInst);
+        }
+    }
+  }
+
+  if (tailCallInsts.empty()) {
+    return false;
+  }
+
+  // 创建一个新的入口基本块，作为循环的前置块
+  auto original_entry = F->getEntryBlock();
+  auto new_entry = F->addBasicBlock("tco.entry." + F->getName());
+  auto loop_header = F->addBasicBlock("tco.loop_header." + F->getName());
+  
+  // 将原入口块中的所有指令移动到循环头块
+  loop_header->getInstructions().splice(loop_header->end(), original_entry->getInstructions());
+  original_entry->setName("tco.pre_header");
+
+  // 为函数参数创建 phi 节点
+  builder->setPosition(loop_header, loop_header->begin());
+  std::vector<PhiInst *> phis;
+  auto original_args = F->getArguments();
+  for (auto &arg : original_args) {
+    auto phi = builder->createPhiInst(arg->getType(), {}, {}, "tco.phi."+arg->getName());
+    phis.push_back(phi);
+  }
+
+  // 用 phi 节点替换所有原始参数的使用
+  for (size_t i = 0; i < original_args.size(); ++i) {
+    original_args[i]->replaceAllUsesWith(phis[i]);
+  }
+
+  // 设置 phi 节点的输入值
+  for (size_t i = 0; i < phis.size(); ++i) {
+    phis[i]->addIncoming(original_args[i], new_entry);
+  }
+
+  // 连接各个基本块
+  builder->setPosition(original_entry, original_entry->end());
+  builder->createUncondBrInst(new_entry);
+  original_entry->addSuccessor(new_entry);
+  
+  builder->setPosition(new_entry, new_entry->end());
+  builder->createUncondBrInst(loop_header);
+  new_entry->addSuccessor(loop_header);
+  loop_header->addPredecessor(new_entry);
+
+  // 处理每一个尾递归调用
+  for (auto callInst : tailCallInsts) {
+    auto tail_call_block = callInst->getParent();
+    
+  // 收集尾递归调用的参数
+    auto args_range = callInst->getArguments();
+    std::vector<Value*> args;
+    std::transform(args_range.begin(), args_range.end(), std::back_inserter(args), 
+                   [](auto& use_ptr){ return use_ptr->getValue(); });
+
+  // 用新的参数值更新 phi 节点
+    for (size_t i = 0; i < phis.size(); ++i) {
+        phis[i]->addIncoming(args[i], tail_call_block);
+    }
+
+  // 移除原有的调用和返回指令
+    auto term_iter = tail_call_block->terminator();
+    SysYIROptUtils::usedelete(term_iter);
+    auto call_iter = tail_call_block->findInstIterator(callInst);
+    SysYIROptUtils::usedelete(call_iter);
+
+  // 添加跳转回循环头块的分支指令
+    builder->setPosition(tail_call_block, tail_call_block->end());
+    builder->createUncondBrInst(loop_header);
+    tail_call_block->addSuccessor(loop_header);
+    loop_header->addPredecessor(tail_call_block);
+  }
+
+  return true;
+}
+
+} // namespace sysy

src/midend/Pass/Pass.cpp

@@ -10,6 +10,7 @@
 #include "DCE.h"
 #include "Mem2Reg.h"
 #include "Reg2Mem.h"
+#include "GVN.h"
 #include "SCCP.h"
 #include "BuildCFG.h"
 #include "LargeArrayToGlobal.h"
@@ -17,6 +18,8 @@
 #include "LICM.h"
 #include "LoopStrengthReduction.h"
 #include "InductionVariableElimination.h"
+#include "GlobalStrengthReduction.h"
+#include "TailCallOpt.h"
 #include "Pass.h"
 #include <iostream>
 #include <queue>
@@ -59,6 +62,8 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
     // 注册优化遍
     registerOptimizationPass<BuildCFG>();
     registerOptimizationPass<LargeArrayToGlobalPass>();
+
+    registerOptimizationPass<GVN>();
     
     registerOptimizationPass<SysYDelInstAfterBrPass>();
     registerOptimizationPass<SysYDelNoPreBLockPass>();
@@ -74,7 +79,10 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
     registerOptimizationPass<LICM>(builderIR);
     registerOptimizationPass<LoopStrengthReduction>(builderIR);
     registerOptimizationPass<InductionVariableElimination>();
+
+    registerOptimizationPass<GlobalStrengthReduction>(builderIR);
     registerOptimizationPass<Reg2Mem>(builderIR);
+    registerOptimizationPass<TailCallOpt>(builderIR);
 
     registerOptimizationPass<SCCP>(builderIR);
 
@@ -129,6 +137,25 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
         printPasses();
       }
 
+      this->clearPasses();
+      this->addPass(&GVN::ID);
+      this->run();
+
+      this->clearPasses();
+      this->addPass(&TailCallOpt::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After TailCallOpt ===\n";
+        SysYPrinter printer(moduleIR);
+        printer.printIR();
+      }
+
+      if(DEBUG) {
+        std::cout << "=== IR After GVN Optimizations ===\n";
+        printPasses();
+      }
+
       this->clearPasses();
       this->addPass(&SCCP::ID);
       this->run();
@@ -140,19 +167,46 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
 
       this->clearPasses();
       this->addPass(&LoopNormalizationPass::ID);
-      this->addPass(&LICM::ID);
-      this->addPass(&LoopStrengthReduction::ID);
       this->addPass(&InductionVariableElimination::ID);
       this->run();
 
       if(DEBUG) {
-        std::cout << "=== IR After Loop Normalization, LICM, and Strength Reduction Optimizations ===\n";
+        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 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();
+      // 全局强度削弱优化，包括代数优化和魔数除法
+      this->clearPasses();
+      this->addPass(&GlobalStrengthReduction::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After Global Strength Reduction Optimizations ===\n";
+        printPasses();
+      }
+
+      this->clearPasses();
+      this->addPass(&Reg2Mem::ID);
+      this->run();
 
       if(DEBUG) {
         std::cout << "=== IR After Reg2Mem Optimizations ===\n";