diff --git a/hercules_cg/src/rt.rs b/hercules_cg/src/rt.rs
index 313f7c10ad8b4d56c8b5a45bc7aca315aab0f807..cbf70eec682be6dff91016e0f1b3722ce1fea0fa 100644
--- a/hercules_cg/src/rt.rs
+++ b/hercules_cg/src/rt.rs
@@ -138,6 +138,7 @@ struct RTContext<'a> {
 #[derive(Debug, Clone, Default)]
 struct RustBlock {
     prologue: String,
+    arc_clones: String,
     data: String,
     phi_tmp_assignments: String,
     phi_assignments: String,
@@ -268,8 +269,9 @@ impl<'a> RTContext<'a> {
             } else {
                 write!(
                     w,
-                    "{}{}{}{}{}",
+                    "{}{}{}{}{}{}",
                     block.prologue,
+                    block.arc_clones,
                     block.data,
                     block.phi_tmp_assignments,
                     block.phi_assignments,
@@ -566,12 +568,14 @@ impl<'a> RTContext<'a> {
                 assert_eq!(control, bb);
                 // The device backends ensure that device functions have the
                 // same interface as AsyncRust functions.
-                let block = &mut blocks.get_mut(&bb).unwrap().data;
+                let block = &mut blocks.get_mut(&bb).unwrap();
+                let arc_clones = &mut block.arc_clones;
+                let block = &mut block.data;
                 let is_async = func.schedules[id.idx()].contains(&Schedule::AsyncCall);
                 if is_async {
                     for arg in args {
                         if let Some(arc) = self.clone_arc(*arg) {
-                            write!(block, "{}", arc)?;
+                            write!(arc_clones, "{}", arc)?;
                         }
                     }
                 }
@@ -580,11 +584,13 @@ impl<'a> RTContext<'a> {
                     (Device::AsyncRust, false) | (_, false) => {
                         format!("{} = ", self.get_value(id, bb, true))
                     }
-                    (_, true) => format!(
-                        "{}*async_call_{}.lock().await = Some(::async_std::task::spawn(async move {{ ",
-                        self.clone_arc(id).unwrap(),
-                        id.idx(),
-                    ),
+                    (_, true) => {
+                        write!(arc_clones, "{}", self.clone_arc(id).unwrap())?;
+                        format!(
+                            "*async_call_{}.lock().await = Some(::async_std::task::spawn(async move {{ ",
+                            id.idx(),
+                        )
+                    }
                 };
                 let postfix = match (device, is_async) {
                     (Device::AsyncRust, false) => ".await",