can pass loop3

Documentations/4.2-gvn/README.md

 # Lab4 实验文档
 
 - [Lab4 实验文档](#lab4-实验文档)
+  
     - [0. 前言](#0-前言)
+  
     - [1. GVN 基础知识](#1-gvn-基础知识)
+      
         - [1.1 GVN 简介](#11-gvn-简介)
         - [1.2 GVN 相关概念](#12-gvn-相关概念)
             - [1. IR 假设](#1-ir-假设)
@@ -14,8 +17,11 @@
             - [7. Join 操作](#7-join-操作)
             - [8. 变量等价与表达式等价](#8-变量等价与表达式等价)
             - [9. Transfer Function](#9-transfer-function)
+  
     - [2. GVN 算法（论文中提供的伪代码）](#2-gvn-算法论文中提供的伪代码)
+  
     - [3. 实验内容](#3-实验内容)
+      
         - [3.1 GVN pass 实现内容要求](#31-gvn-pass-实现内容要求)
         - [3.2 GVN 辅助类](#32-gvn-辅助类)
         - [3.3 注册及运行 GVN Pass](#33-注册及运行-gvn-pass)
@@ -23,8 +29,11 @@
             - [运行 Pass](#运行-pass)
         - [3.3 自动测试](#33-自动测试)
         - [3.4 Tips](#34-tips)
+  
     - [4. 提交要求](#4-提交要求)
+      
         - [目录结构](#目录结构)
+      
         - [提交要求和评分标准](#提交要求和评分标准)
           
           ## 0. 前言

gvn.json

+[{
+"function": "main", 
+"pout": {"label_entry": [["%op0", ], ["%op1", ], ["%op2", "%op3", ], ],}},]
\ No newline at end of file

src/optimization/GVN.cpp

@@ -263,9 +263,7 @@ GVN::intersect(shared_ptr<CongruenceClass> ci, shared_ptr<CongruenceClass> cj) {
     if (c->members_.size()) // not empty
     {
         if (c->index_ == 0) {
-            // it must be a phi instruction
-            // and be separated to 2 copy statement
-            // we should use the copy-stmt int the previous block
+            // we should use the `index` int the previous block
             auto instr = static_cast<Instruction *>(*c->members_.begin());
             auto instr_phi = dynamic_cast<PhiInst *>(instr);
             int exact_idx;
@@ -570,7 +568,6 @@ GVN::transferFunction(Instruction *instr, Value *e, partitions pin) {
         }
 
     // TODO: get different ValueExpr by Instruction::OpID, modify pout
-    // ??
     // get ve and vpf
     shared_ptr<Expression> ve;
     if (e) {