From 9c87cb397bf1c68187cd722a4d0c7c0515e92e07 Mon Sep 17 00:00:00 2001
From: Lixuanwang <xlwmail@nudt.edu.cn>
Date: Tue, 22 Jul 2025 00:07:54 +0800
Subject: [PATCH] =?UTF-8?q?[backend]=E8=A7=A3=E5=86=B3=E4=BA=86=E9=9D=9E?=
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---
 src/RISCv64ISel.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/src/RISCv64ISel.cpp b/src/RISCv64ISel.cpp
index 2da2373..fdef521 100644
--- a/src/RISCv64ISel.cpp
+++ b/src/RISCv64ISel.cpp
@@ -238,7 +238,52 @@ void RISCv64ISel::selectNode(DAGNode* node) {
             auto bin = dynamic_cast<BinaryInst*>(node->value);
             Value* lhs = bin->getLhs();
             Value* rhs = bin->getRhs();
+            
+            // 检查是否是“基地址+偏移量”的地址计算模式
+            if (bin->getKind() == BinaryInst::kAdd) {
+                Value* base = nullptr;
+                Value* offset = nullptr;
 
+                // 判断哪个是基地址（AllocaInst），哪个是偏移量
+                if (dynamic_cast<AllocaInst*>(lhs)) {
+                    base = lhs;
+                    offset = rhs;
+                } else if (dynamic_cast<AllocaInst*>(rhs)) {
+                    base = rhs;
+                    offset = lhs;
+                }
+                
+                // 如果成功匹配到该模式
+                if (base) {
+                    // [最终修复]
+                    // 1. 先为偏移量加载常量（如果它是常量的话）
+                    if (auto const_offset = dynamic_cast<ConstantValue*>(offset)) {
+                        auto li = std::make_unique<MachineInstr>(RVOpcodes::LI);
+                        li->addOperand(std::make_unique<RegOperand>(getVReg(const_offset)));
+                        li->addOperand(std::make_unique<ImmOperand>(const_offset->getInt()));
+                        CurMBB->addInstruction(std::move(li));
+                    }
+                    
+                    // 2. 使用FRAME_ADDR伪指令来获取基地址
+                    auto base_addr_vreg = getNewVReg(); // 创建一个新的临时vreg来存放基地址
+                    auto frame_addr_instr = std::make_unique<MachineInstr>(RVOpcodes::FRAME_ADDR);
+                    frame_addr_instr->addOperand(std::make_unique<RegOperand>(base_addr_vreg));
+                    frame_addr_instr->addOperand(std::make_unique<RegOperand>(getVReg(base)));
+                    CurMBB->addInstruction(std::move(frame_addr_instr));
+
+                    // 3. 生成真正的add指令，计算最终地址
+                    auto final_addr_vreg = getVReg(bin); // 这是整个二元运算的结果vreg
+                    auto offset_vreg = getVReg(offset);
+                    auto add_instr = std::make_unique<MachineInstr>(RVOpcodes::ADD); // 指针运算是64位
+                    add_instr->addOperand(std::make_unique<RegOperand>(final_addr_vreg));
+                    add_instr->addOperand(std::make_unique<RegOperand>(base_addr_vreg));
+                    add_instr->addOperand(std::make_unique<RegOperand>(offset_vreg));
+                    CurMBB->addInstruction(std::move(add_instr));
+                    
+                    return; // 地址计算处理完毕，直接返回
+                }
+            }
+            
             // [V2优点] 在BINARY节点内部按需加载常量操作数。
             auto load_val_if_const = [&](Value* val) {
                 if (auto c = dynamic_cast<ConstantValue*>(val)) {