diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 68bbc1520a06d..7f7e3e492f4ef 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -1741,7 +1741,7 @@ fn parse_jobs_all(
                 check_upper_limit(frontend, opt_name);
                 frontend
             }
-            None => jobs.flatten(),
+            None => jobs.flatten().or(NonZero::new(1)),
         },
     };
     let backend = match matches.opt_str("jobs-backend") {