diff --git a/src/RISCv64RegAlloc.cpp b/src/RISCv64RegAlloc.cpp
index 5edcf98..329ddb8 100644
--- a/src/RISCv64RegAlloc.cpp
+++ b/src/RISCv64RegAlloc.cpp
@@ -436,8 +436,12 @@ void RISCv64RegAlloc::rewriteFunction() {
                     if (reg_op->isVirtual()) {
                         unsigned vreg = reg_op->getVRegNum();
                         if (color_map.count(vreg)) {
-                            // 如果vreg被成功着色，替换为物理寄存器
-                            reg_op->setPReg(color_map.at(vreg));
+                            PhysicalReg preg = color_map.at(vreg);
+                            reg_op->setPReg(preg);
+                            // 检查这个物理寄存器是否是 s0-s11
+                            if (preg >= PhysicalReg::S0 && preg <= PhysicalReg::S11) {
+                                used_callee_saved_regs.insert(preg);
+                            }
                         } else if (spilled_vregs.count(vreg)) {
                             // 如果vreg被溢出，替换为专用的溢出物理寄存器t6
                             reg_op->setPReg(PhysicalReg::T6);
diff --git a/src/include/RISCv64RegAlloc.h b/src/include/RISCv64RegAlloc.h
index 724ad1c..dc63e62 100644
--- a/src/include/RISCv64RegAlloc.h
+++ b/src/include/RISCv64RegAlloc.h
@@ -54,8 +54,11 @@ private:
     // 这个map将在run()函数开始时被填充，并在rewriteFunction()中使用。
     std::map<unsigned, Value*> vreg_to_value_map;
 
+    std::set<PhysicalReg> used_callee_saved_regs;
+    
     // 用于计算类型大小的辅助函数
     unsigned getTypeSizeInBytes(Type* type);
+    
 };
 
 } // namespace sysy