[midend-GVN]初步构建GVN，能够优化部分CSE无法处理的子表达式但是有错误需要debug。

src/midend/Pass/Pass.cpp

@@ -10,6 +10,7 @@
 #include "DCE.h"
 #include "Mem2Reg.h"
 #include "Reg2Mem.h"
+#include "GVN.h"
 #include "SCCP.h"
 #include "BuildCFG.h"
 #include "LargeArrayToGlobal.h"
@@ -59,6 +60,8 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
     // 注册优化遍
     registerOptimizationPass<BuildCFG>();
     registerOptimizationPass<LargeArrayToGlobalPass>();
+
+    registerOptimizationPass<GVN>();
     
     registerOptimizationPass<SysYDelInstAfterBrPass>();
     registerOptimizationPass<SysYDelNoPreBLockPass>();
@@ -129,6 +132,16 @@ void PassManager::runOptimizationPipeline(Module* moduleIR, IRBuilder* builderIR
         printPasses();
       }
 
+      // 添加GVN优化遍
+      this->clearPasses();
+      this->addPass(&GVN::ID);
+      this->run();
+
+      if(DEBUG) {
+        std::cout << "=== IR After GVN Optimizations ===\n";
+        printPasses();
+      }
+
       this->clearPasses();
       this->addPass(&SCCP::ID);
       this->run();