diff --git a/driver/tool.cpp b/driver/tool.cpp
index 7d1a7f0e80..b14347241b 100644
--- a/driver/tool.cpp
+++ b/driver/tool.cpp
@@ -121,8 +121,10 @@ void appendTargetArgsForGcc(std::vector<std::string> &args) {
     return;
 
   case Triple::riscv64:
+    if (triple.isArch64Bit()) {
       args.push_back("-march=rv64gc");
       args.push_back("-mabi=lp64d");
+    }
     return;
 
   default: