From 46179e38662c9f56c238f3aed1269aed8718830a Mon Sep 17 00:00:00 2001
From: rain2133 <1370973498@qq.com>
Date: Mon, 11 Aug 2025 18:40:58 +0800
Subject: [PATCH] =?UTF-8?q?[midend-CFGOpt]=E4=BF=AE=E5=A4=8D=E9=83=A8?=
 =?UTF-8?q?=E5=88=86=E6=8C=87=E4=BB=A4=E5=88=A0=E9=99=A4=E9=80=BB=E8=BE=91?=
 =?UTF-8?q?=E9=94=99=E8=AF=AF?=
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---
 src/midend/Pass/Optimize/SysYIRCFGOpt.cpp | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/midend/Pass/Optimize/SysYIRCFGOpt.cpp b/src/midend/Pass/Optimize/SysYIRCFGOpt.cpp
index 393df63..3477864 100644
--- a/src/midend/Pass/Optimize/SysYIRCFGOpt.cpp
+++ b/src/midend/Pass/Optimize/SysYIRCFGOpt.cpp
@@ -42,7 +42,7 @@ bool SysYCFGOptUtils::SysYDelInstAfterBr(Function *func) {
       ++Branchiter;
     while (Branchiter != instructions.end()) {
       changed = true;
-      Branchiter = instructions.erase(Branchiter);
+      Branchiter = SysYIROptUtils::usedelete(Branchiter); // 删除指令
     }
 
     if (Branch) { // 更新前驱后继关系
@@ -91,7 +91,7 @@ bool SysYCFGOptUtils::SysYBlockMerge(Function *func) {
         BasicBlock *block = blockiter->get();
         BasicBlock *nextBlock = blockiter->get()->getSuccessors()[0];
         // auto nextarguments = nextBlock->getArguments();
-        // 删除br指令
+        // 删除block的br指令
         if (block->getNumInstructions() != 0) {
           auto thelastinstinst = block->terminator();
           if (thelastinstinst->get()->isUnconditional()) {
@@ -103,14 +103,20 @@ bool SysYCFGOptUtils::SysYBlockMerge(Function *func) {
             if (brinst->getThenBlock() == brinst->getElseBlock()) {
               thelastinstinst = SysYIROptUtils::usedelete(thelastinstinst);
             }
+            else{
+              assert(false && "SysYBlockMerge: unexpected conditional branch with different then and else blocks");
+            }
           }
         }
         // 将后继块的指令移动到当前块
         // 并将后继块的父指针改为当前块
         for (auto institer = nextBlock->begin(); institer != nextBlock->end();) {
-          institer->get()->setParent(block);
-          block->getInstructions().emplace_back(institer->release());
-          institer = nextBlock->getInstructions().erase(institer);
+          // institer->get()->setParent(block);
+          // block->getInstructions().emplace_back(institer->release());
+          // 用usedelete删除会导致use关系被删除我只希望移动指令到当前块
+          // institer = SysYIROptUtils::usedelete(institer);
+          // institer = nextBlock->getInstructions().erase(institer);
+          nextBlock->moveInst(institer, block->getInstructions().end(), block);
         }
         // 更新前驱后继关系，类似树节点操作
         block->removeSuccessor(nextBlock);