diff --git a/disassembler/disassembler.cc b/disassembler/disassembler.cc
index 53461ce..a05183a 100644
--- a/disassembler/disassembler.cc
+++ b/disassembler/disassembler.cc
@@ -62,6 +62,7 @@
       return new x86::DisassemblerX86(options, /* supports_rex= */ true);
 #endif
     default:
+      UNUSED(options);
       UNIMPLEMENTED(FATAL) << static_cast<uint32_t>(instruction_set);
       UNREACHABLE();
   }