diff --git a/cranelift/codegen/src/isa/aarch64/lower.isle b/cranelift/codegen/src/isa/aarch64/lower.isle
index 13f0cfd28c6c..08550ae26d23 100644
--- a/cranelift/codegen/src/isa/aarch64/lower.isle
+++ b/cranelift/codegen/src/isa/aarch64/lower.isle
@@ -768,7 +768,7 @@
 
 ;; Special cases for when we're subtracting an extended register where the
 ;; extending operation can get folded into the sub itself.
-(rule 1 (lower (has_type (fits_in_64 ty) (isub x (extended_value_from_value y))))
+(rule isub_extend 1 (lower (has_type (fits_in_64 ty) (isub x (extended_value_from_value y))))
       (sub_extend ty x y))
 
 ;; Finally a special case for when we're subtracting the shift of a different