[midend-phielimination]消除只有一个incomingvalue的phi指令

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

@@ -110,14 +110,18 @@ public:
 
   
   // PHI指令消除相关方法
-  static void eliminateRedundantPhisInFunction(Function* func){
+  static bool eliminateRedundantPhisInFunction(Function* func){
+    bool changed = false;
     std::vector<Instruction *> toDelete;
     for (auto &bb : func->getBasicBlocks()) {
       for (auto &inst : bb->getInstructions()) {
         if (auto phi = dynamic_cast<PhiInst *>(inst.get())) {
           auto incoming = phi->getIncomingValues();
+          if(DEBUG){
+            std::cout << "Checking Phi: " << phi->getName() << " with " << incoming.size() << " incoming values." << std::endl;
+          }
           if (incoming.size() == 1) {
-            Value *singleVal = incoming[0].first;
+            Value *singleVal = incoming[0].second;
             inst->replaceAllUsesWith(singleVal);
             toDelete.push_back(inst.get());
           }
@@ -128,7 +132,9 @@ public:
     }
     for (auto *phi : toDelete) {
       usedelete(phi);
+      changed = true; // 标记为已更改
     }
+    return changed; // 返回是否有删除发生
   }
 
   //该实现参考了libdivide的算法