diff --git a/yjit/src/backend/ir.rs b/yjit/src/backend/ir.rs
index 5f69f5a01f..7477f375ac 100644
--- a/yjit/src/backend/ir.rs
+++ b/yjit/src/backend/ir.rs
@@ -1568,7 +1568,7 @@ impl AssemblerDrainingIterator {
         Self {
             insns: asm.insns.into_iter().peekable(),
             index: 0,
-            indices: Vec::default()
+            indices: Vec::with_capacity(ASSEMBLER_INSNS_CAPACITY),
         }
     }