[midend]修改GEP指令定义，更靠近llvm ir设计，增加自动推断类型函数，修复generator中错误生成ir的逻辑

src/include/IR.h

@@ -1124,24 +1124,24 @@ public:
 
 
 class GetElementPtrInst : public Instruction {
-  friend class IRBuilder; // 如果您有IRBuilder来创建指令，需要friend
+  friend class IRBuilder;
 
 protected:
   // GEP的构造函数：
   // resultType: GEP计算出的地址的类型 (通常是指向目标元素类型的指针)
   // basePointer: 基指针 (第一个操作数)
   // indices: 索引列表 (后续操作数)
-  GetElementPtrInst(Value *basePointer,
-                      const std::vector<Value *> &indices = {},
-                      BasicBlock *parent = nullptr, const std::string &name = "")
-      : Instruction(Kind::kGetElementPtr, basePointer->getType(), parent, name) {
+  GetElementPtrInst(Type *resultType,
+                    Value *basePointer,
+                    const std::vector<Value *> &indices = {},
+                    BasicBlock *parent = nullptr, const std::string &name = "")
+      : Instruction(Kind::kGetElementPtr, resultType, parent, name) {
     assert(basePointer && "GEP base pointer cannot be null!");
     // TODO : 安全检查
     assert(basePointer->getType()->isPointer() );
     addOperand(basePointer); // 第一个操作数是基指针
     addOperands(indices);    // 随后的操作数是索引
   }
-
 public:
   Value* getBasePointer() const { return getOperand(0); }
   unsigned getNumIndices() const { return getNumOperands() - 1; }
@@ -1155,7 +1155,7 @@ public:
   static GetElementPtrInst* create(Type *resultType, Value *basePointer,
                                     const std::vector<Value *> &indices = {},
                                     BasicBlock *parent = nullptr, const std::string &name = "") {
-    return new GetElementPtrInst(basePointer, indices, parent, name);
+    return new GetElementPtrInst(resultType, basePointer, indices, parent, name);
   }
 };