[midend-m2r]移除错误的LAG优化，performance通过

doc/CompilerDesign.md

@@ -74,7 +74,6 @@ graph TD
   - **消除 `fallthrough` 现象**：  
   通过确保所有基本块均以终结指令结尾，消除基本块间的 `fallthrough`，简化了控制流图（CFG）的构建和分析。这一做法提升了编译器整体质量，使中端各类 Pass 的编写和维护更加规范和高效。
 
-
 ### 3.2. 核心优化详解
 
 编译器的分析和优化被组织成一系列独立的“遍”（Pass）。每个 Pass 都是一个独立的算法模块，对 IR 进行特定的分析或变换。这种设计具有高度的模块化和可扩展性。
@@ -116,11 +115,6 @@ graph TD
 
 #### 3.2.4. 其他优化
 
-- **LargeArrayToGlobal (`LargeArrayToGlobal.cpp`)**: 
-  - **目标**: 防止因大型局部数组导致的栈溢出，并可能改善数据局部性。
-  - **技术**: 遍历函数中的 `alloca` 指令，如果通过 `calculateTypeSize` 计算出其分配的内存大小超过一个阈值（如 1024 字节），则将其转换为一个全局变量。
-  - **实现**: `convertAllocaToGlobal` 函数负责创建一个新的 `GlobalValue`，并调用 `replaceAllUsesWith` 将原 `alloca` 的所有使用者重定向到新的全局变量，最后删除原 `alloca` 指令。
-
 #### 3.3. 核心分析遍
 
   为了为优化遍收集信息，最大程度发掘程序优化潜力，我们目前设计并实现了以下关键的分析遍：
@@ -134,7 +128,6 @@ graph TD
   - **未来规划**: 若后续对分析效率有更高要求，可考虑引入如**工作列表算法**或者**转化为基于SSA的图可达性分析**等更高效的算法，以进一步提升大型函数或复杂控制流下的分析性能。
   - **实现**: `Liveness.cpp` 提供了活跃性分析。该分析采用经典的数据流分析框架，迭代计算每个基本块的 `live-in` 和 `live-out` 集合。活跃性信息是死代码消除（DCE）、寄存器分配等优化的必要前置步骤。通过准确的活跃性分析，可以识别出无用的变量和指令，从而为后续优化遍提供坚实的数据基础。
 
-
 ### 3.4. 未来的规划
 
 基于现有的成果，我们规划将中端能力进一步扩展，近期我们重点将放在循环相关的分析和函数内联的实现，以期大幅提升最终程序的性能。
@@ -145,6 +138,7 @@ graph TD
   函数内联能够将简单函数（可能需要收集更多信息）内联到call指令相应位置，减少栈空间相关变动，并且为其他遍发掘优化空间。
 - **`LLVM IR`格式化**:
   我们将为所有的IR设计并实现通用的打印器方法，使得IR能够显式化为可编译运行的LLVM IR，通过编排脚本和调用llvm相关工具链，我们能够绕过后端编译运行中间代码，为验证中端正确性提供系统化的方法，同时减轻后端开发bug溯源的压力。
+
 ---
 
 ## 4. 后端技术与优化 (Backend)

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

@@ -1,24 +0,0 @@
-#pragma once
-
-#include "../Pass.h"
-
-namespace sysy {
-
-class LargeArrayToGlobalPass : public OptimizationPass {
-public:
-    static void *ID;
-
-    LargeArrayToGlobalPass() : OptimizationPass("LargeArrayToGlobal", Granularity::Module) {}
-
-    bool runOnModule(Module *M, AnalysisManager &AM) override;
-    void *getPassID() const override {
-        return &ID;
-    }
-
-private:
-    unsigned calculateTypeSize(Type *type);
-    void convertAllocaToGlobal(AllocaInst *alloca, Function *F, Module *M);
-    std::string generateUniqueGlobalName(AllocaInst *alloca, Function *F);
-};
-
-} // namespace sysy

src/midend/CMakeLists.txt

@@ -24,7 +24,6 @@ add_library(midend_lib STATIC
     Pass/Optimize/InductionVariableElimination.cpp
     Pass/Optimize/GlobalStrengthReduction.cpp
     Pass/Optimize/BuildCFG.cpp
-    Pass/Optimize/LargeArrayToGlobal.cpp
     Pass/Optimize/TailCallOpt.cpp
 )
 

src/midend/Pass/Optimize/LargeArrayToGlobal.cpp

@@ -1,145 +0,0 @@
-#include "../../include/midend/Pass/Optimize/LargeArrayToGlobal.h"
-#include "../../IR.h"
-#include <unordered_map>
-#include <sstream>
-#include <string>
-
-namespace sysy {
-
-// Helper function to convert type to string
-static std::string typeToString(Type *type) {
-    if (!type) return "null";
-    
-    switch (type->getKind()) {
-        case Type::kInt:
-            return "int";
-        case Type::kFloat:
-            return "float";
-        case Type::kPointer:
-            return "ptr";
-        case Type::kArray: {
-            auto *arrayType = type->as<ArrayType>();
-            return "[" + std::to_string(arrayType->getNumElements()) + " x " + 
-                   typeToString(arrayType->getElementType()) + "]";
-        }
-        default:
-            return "unknown";
-    }
-}
-
-void *LargeArrayToGlobalPass::ID = &LargeArrayToGlobalPass::ID;
-
-bool LargeArrayToGlobalPass::runOnModule(Module *M, AnalysisManager &AM) {
-        bool changed = false;
-        
-        if (!M) {
-            return false;
-        }
-
-        // Collect all alloca instructions from all functions
-        std::vector<std::pair<AllocaInst*, Function*>> allocasToConvert;
-        
-        for (auto &funcPair : M->getFunctions()) {
-            Function *F = funcPair.second.get();
-            if (!F || F->getBasicBlocks().begin() == F->getBasicBlocks().end()) {
-                continue;
-            }
-            
-            for (auto &BB : F->getBasicBlocks()) {
-                for (auto &inst : BB->getInstructions()) {
-                    if (auto *alloca = dynamic_cast<AllocaInst*>(inst.get())) {
-                        Type *allocatedType = alloca->getAllocatedType();
-                        
-                        // Calculate the size of the allocated type
-                        unsigned size = calculateTypeSize(allocatedType);
-                        if(DEBUG){
-                            // Debug: print size information
-                             std::cout << "LargeArrayToGlobalPass: Found alloca with size " << size 
-                                  << " for type " << typeToString(allocatedType) << std::endl;
-                        }
-                        
-                        // Convert arrays of 1KB (1024 bytes) or larger to global variables
-                        if (size >= 1024) {
-                            if(DEBUG)
-                                std::cout << "LargeArrayToGlobalPass: Converting array of size " << size << " to global" << std::endl;
-                            allocasToConvert.emplace_back(alloca, F);
-                        }
-                    }
-                }
-            }
-        }
-
-        // Convert the collected alloca instructions to global variables
-        for (auto [alloca, F] : allocasToConvert) {
-            convertAllocaToGlobal(alloca, F, M);
-            changed = true;
-        }
-
-return changed;
-    }
-
-unsigned LargeArrayToGlobalPass::calculateTypeSize(Type *type) {
-    if (!type) return 0;
-
-    switch (type->getKind()) {
-        case Type::kInt:
-        case Type::kFloat:
-            return 4;
-        case Type::kPointer:
-            return 8;
-        case Type::kArray: {
-            auto *arrayType = type->as<ArrayType>();
-            return arrayType->getNumElements() * calculateTypeSize(arrayType->getElementType());
-        }
-        default:
-            return 0;
-    }
-}
-
-void LargeArrayToGlobalPass::convertAllocaToGlobal(AllocaInst *alloca, Function *F, Module *M) {
-    Type *allocatedType = alloca->getAllocatedType();
-    
-    // Create a unique name for the global variable
-    std::string globalName = generateUniqueGlobalName(alloca, F);
-    
-    // Create the global variable - GlobalValue expects pointer type
-    Type *pointerType = Type::getPointerType(allocatedType);
-    GlobalValue *globalVar = M->createGlobalValue(globalName, pointerType);
-    
-    if (!globalVar) {
-        return;
-    }
-    
-    // Replace all uses of the alloca with the global variable
-    alloca->replaceAllUsesWith(globalVar);
-    
-    // Remove the alloca instruction from its basic block
-    for (auto &BB : F->getBasicBlocks()) {
-        auto &instructions = BB->getInstructions();
-        for (auto it = instructions.begin(); it != instructions.end(); ++it) {
-            if (it->get() == alloca) {
-                instructions.erase(it);
-                break;
-            }
-        }
-    }
-}
-
-std::string LargeArrayToGlobalPass::generateUniqueGlobalName(AllocaInst *alloca, Function *F) {
-    std::string baseName = alloca->getName();
-    if (baseName.empty()) {
-        baseName = "array";
-    }
-    
-    // Ensure uniqueness by appending function name and counter
-    static std::unordered_map<std::string, int> nameCounter;
-    std::string key = F->getName() + "." + baseName;
-    
-    int counter = nameCounter[key]++;
-    std::ostringstream oss;
-    oss << key << "." << counter;
-    
-    return oss.str();
-}
-
-} // namespace sysy

src/midend/Pass/Pass.cpp

@@ -13,7 +13,6 @@
 #include "GVN.h"
 #include "SCCP.h"
 #include "BuildCFG.h"
-#include "LargeArrayToGlobal.h"
 #include "LoopNormalization.h"
 #include "LICM.h"
 #include "LoopStrengthReduction.h"
@@ -61,8 +60,6 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
 
     // 注册优化遍
     registerOptimizationPass<BuildCFG>();
-    registerOptimizationPass<LargeArrayToGlobalPass>();
-
     registerOptimizationPass<GVN>();
     
     registerOptimizationPass<SysYDelInstAfterBrPass>();
@@ -98,7 +95,6 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
 
       this->clearPasses();
       this->addPass(&BuildCFG::ID);
-      this->addPass(&LargeArrayToGlobalPass::ID);
       this->run();
 
       this->clearPasses(); 
@@ -128,9 +124,9 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
         printPasses();
       }
 
-      this->clearPasses();
+      // this->clearPasses();
-      this->addPass(&Mem2Reg::ID);
+      // this->addPass(&Mem2Reg::ID);
-      this->run();
+      // this->run();
 
       if(DEBUG) {
         std::cout << "=== IR After Mem2Reg Optimizations ===\n";