1 files changed, 0 insertions, 2 deletions
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 99e9e8794e3..30e577a5172 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -572,8 +572,6 @@ impl Step for Miri {
                 return;
             }
 
-            // # Run `cargo test` with `-Zmir-opt-level=4`.
-            cargo.env("MIRIFLAGS", "-O -Zmir-opt-level=4");
             if !try_run(builder, &mut cargo) {
                 return;
             }