[backend]修复了多参数传递的错误

src/backend/RISCv64/RISCv64AsmPrinter.cpp

@@ -144,6 +144,9 @@ void RISCv64AsmPrinter::printInstruction(MachineInstr* instr, bool debug) {
         case RVOpcodes::FRAME_STORE_F:
             if (!debug) throw std::runtime_error("FRAME_STORE_F not eliminated before AsmPrinter");
             *OS << "frame_store_f ";  break;
+        case RVOpcodes::PSEUDO_KEEPALIVE:
+            if (!debug) throw std::runtime_error("PSEUDO_KEEPALIVE not eliminated before AsmPrinter");
+            *OS << "keepalive ";  break;
         default: 
             throw std::runtime_error("Unknown opcode in AsmPrinter");
     }