diff --git a/insns.def b/insns.def
index 34cbaa4d35..f75007dca2 100644
--- a/insns.def
+++ b/insns.def
@@ -498,7 +498,6 @@ concatarray
 (VALUE ary1, VALUE ary2st)
 (VALUE ary)
 {
-    const VALUE *sp = GET_SP();
     const VALUE ary2 = ary2st;
     VALUE tmp1 = rb_check_convert_type(ary1, T_ARRAY, "Array", "to_a");
     VALUE tmp2 = rb_check_convert_type(ary2, T_ARRAY, "Array", "to_a");