diff --git a/cranelift/codegen/src/ir/dfg.rs b/cranelift/codegen/src/ir/dfg.rs
index 49f6fdbd73..9e8634b741 100644
--- a/cranelift/codegen/src/ir/dfg.rs
+++ b/cranelift/codegen/src/ir/dfg.rs
@@ -104,6 +104,7 @@ impl DataFlowGraph {
         self.value_lists.clear();
         self.values.clear();
         self.signatures.clear();
+        self.old_signatures.clear();
         self.ext_funcs.clear();
         self.values_labels = None;
         self.constants.clear();