diff --git a/Readme.md b/Readme.md
index 6759403b64f..61595e97730 100644
--- a/Readme.md
+++ b/Readme.md
@@ -69,7 +69,7 @@ function jit_calc() {
     to make it possible to use incremental mode for all analyses performed by rustc without caching
     object files when their content should have been changed by a change to cg_clif.</dd>
     <dt>CG_CLIF_DISPLAY_CG_TIME</dt>
-    <dd>Display the time it took to perform codegen for a crate</dd>
+    <dd>If "1", display the time it took to perform codegen for a crate</dd>
 </dl>
 
 ## Not yet supported
diff --git a/src/driver/mod.rs b/src/driver/mod.rs
index d75b6e05f32..9a60b1e6a33 100644
--- a/src/driver/mod.rs
+++ b/src/driver/mod.rs
@@ -109,7 +109,7 @@ fn trans_mono_item<'tcx, B: Backend + 'static>(
 }
 
 fn time<R>(tcx: TyCtxt<'_>, name: &'static str, f: impl FnOnce() -> R) -> R {
-    if std::env::var("CG_CLIF_DISPLAY_CG_TIME").is_ok() {
+    if std::env::var("CG_CLIF_DISPLAY_CG_TIME").as_ref().map(|val| &**val) == Ok("1") {
         println!("[{:<30}: {}] start", tcx.crate_name(LOCAL_CRATE), name);
         let before = std::time::Instant::now();
         let res = tcx.sess.time(name, f);