[midend-LICM]优化了特征分析中对循环不变量的识别，实现了LICM遍，格式化副作用分析代码

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

@@ -0,0 +1,40 @@
+#pragma once
+#include "Pass.h"
+#include "Loop.h"
+#include "LoopCharacteristics.h"
+#include "Dom.h"
+#include <unordered_set>
+#include <vector>
+
+namespace sysy{
+
+class LICMContext {
+public:
+  LICMContext(Function* func, Loop* loop, IRBuilder* builder, const LoopCharacteristics* chars)
+    : func(func), loop(loop), builder(builder), chars(chars) {}
+    // 运行LICM主流程，返回IR是否被修改
+    bool run();
+
+private:
+    Function* func;
+    Loop* loop;
+    IRBuilder* builder;
+    const LoopCharacteristics* chars; // 特征分析结果
+
+    // 外提所有可提升指令
+    bool hoistInstructions();
+};
+
+
+class LICM : public OptimizationPass{
+private:
+	IRBuilder *builder; ///< IR构建器，用于插入指令
+public:
+	static void *ID;
+	LICM(IRBuilder *builder = nullptr) : OptimizationPass("LICM", Granularity::Function) , builder(builder) {}
+	bool runOnFunction(Function *F, AnalysisManager &AM) override;
+	void getAnalysisUsage(std::set<void *> &, std::set<void *> &) const override;
+	void *getPassID() const override { return &ID; }
+};
+
+} // namespace sysy