From d038884ffba636ba6c55fe4e90a4853d223acf69 Mon Sep 17 00:00:00 2001
From: rain2133 <1370973498@qq.com>
Date: Sat, 16 Aug 2025 15:43:51 +0800
Subject: [PATCH] =?UTF-8?q?[midend-GVN]=20commit=E5=A4=B4=E6=96=87?=
 =?UTF-8?q?=E4=BB=B6?=
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---
 src/include/midend/Pass/Optimize/GVN.h | 82 ++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 src/include/midend/Pass/Optimize/GVN.h

diff --git a/src/include/midend/Pass/Optimize/GVN.h b/src/include/midend/Pass/Optimize/GVN.h
new file mode 100644
index 0000000..3358e48
--- /dev/null
+++ b/src/include/midend/Pass/Optimize/GVN.h
@@ -0,0 +1,82 @@
+#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:
+    // 值编号的哈希表：Value -> 代表值
+    std::unordered_map<Value*, Value*> hashtable;
+    
+    // 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);
+    
+    // 检查哈希表并获取值编号
+    Value* checkHashtable(Value* value);
+    
+    // 为不同类型的指令获取值编号
+    Value* getValueNumber(Instruction* inst);
+    Value* getValueNumber(BinaryInst* inst);
+    Value* getValueNumber(UnaryInst* inst);
+    Value* getValueNumber(GetElementPtrInst* inst);
+    Value* getValueNumber(LoadInst* inst);
+    Value* getValueNumber(CallInst* inst);
+    
+    // 访问指令并进行GVN优化
+    void visitInstruction(Instruction* inst);
+    
+    // 检查是否可以安全地用一个值替换另一个值
+    bool canReplace(Instruction* original, Value* replacement);
+    
+    // 生成表达式的标准化字符串
+    std::string getCanonicalExpression(Instruction* inst);
+};
+
+// 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