diff --git a/src/plugins/instantiate/instantiator_builder.ml b/src/plugins/instantiate/instantiator_builder.ml
index df9028d122de56f183632d9571c2f3e3056ec14c..6b98b3ad9d26c521d5cbb90be41c7c45bed3383f 100644
--- a/src/plugins/instantiate/instantiator_builder.ml
+++ b/src/plugins/instantiate/instantiator_builder.ml
@@ -46,10 +46,9 @@ module type Instantiator = sig
   val retype_args: override_key -> exp list -> exp list
   val get_override: override_key -> fundec
   val get_kfs: unit -> kernel_function list
-  val mark_as_computed:  ?project:Project.t -> unit -> unit
+  val clear: unit -> unit
 end
 
-
 let build_body caller callee args_generator =
   let open Extlib in
   let loc  = Cil_datatype.Location.unknown in
@@ -68,12 +67,13 @@ let build_body caller callee args_generator =
 module Make_instantiator (G: Generator_sig) = struct
   include G
   module Enabled = Options.NewInstantiator (G)
-  module Cache = State_builder.Hashtbl (G.Hashtbl) (Cil_datatype.Fundec)
-      (struct
-        let size = 5
-        let dependencies = []
-        let name = "Instantiator." ^ G.function_name
-      end)
+  module Cache = struct
+    let tbl = G.Hashtbl.create 13
+    let find = G.Hashtbl.find tbl
+    let add = G.Hashtbl.add tbl
+    let fold f = G.Hashtbl.fold f tbl
+    let clear () = G.Hashtbl.clear tbl
+  end
 
   let make_fundec key =
     let open Globals.Functions in
@@ -113,5 +113,6 @@ module Make_instantiator (G: Generator_sig) = struct
   let get_kfs () =
     Cache.fold (fun _ fd l -> Globals.Functions.get fd.svar :: l) []
 
-  let mark_as_computed = Cache.mark_as_computed
+  let clear () =
+    Cache.clear ()
 end
diff --git a/src/plugins/instantiate/instantiator_builder.mli b/src/plugins/instantiate/instantiator_builder.mli
index e2432608275499398adeb83d13636fb8ea7f2146..87c268d2d49824682e3f4e2d0ddfa18cd7d081ba 100644
--- a/src/plugins/instantiate/instantiator_builder.mli
+++ b/src/plugins/instantiate/instantiator_builder.mli
@@ -123,10 +123,9 @@ module type Instantiator = sig
   *)
   val get_kfs: unit -> kernel_function list
 
-  (** [mark_as_computed ?project ()] applies the [mark_as_computed] on the
-      internal table.
+  (** [clear ()] clears the internal table of the instantiator.
   *)
-  val mark_as_computed:  ?project:Project.t -> unit -> unit
+  val clear: unit -> unit
 end
 
 (** Generates a [Instantiator] from a [Generator_sig] adding all necessary stuff for
diff --git a/src/plugins/instantiate/tests/plugin/ast_clear.c b/src/plugins/instantiate/tests/plugin/ast_clear.c
new file mode 100644
index 0000000000000000000000000000000000000000..d3dfbb6ad2a2fb83924f23cba30589f680d415e9
--- /dev/null
+++ b/src/plugins/instantiate/tests/plugin/ast_clear.c
@@ -0,0 +1,9 @@
+/* run.config
+   OPT: -instantiate -then -pp-annot
+*/
+
+#include <string.h>
+
+int foo(char* s1, char* s2, size_t len){
+  return memcmp(s1, s2, len) ;
+}
\ No newline at end of file
diff --git a/src/plugins/instantiate/tests/plugin/oracle/ast_clear.res.oracle b/src/plugins/instantiate/tests/plugin/oracle/ast_clear.res.oracle
new file mode 100644
index 0000000000000000000000000000000000000000..1a8c67bb4f4a92cf3d5a5f39514eb119d0d7c121
--- /dev/null
+++ b/src/plugins/instantiate/tests/plugin/oracle/ast_clear.res.oracle
@@ -0,0 +1,2 @@
+[kernel] Parsing tests/plugin/ast_clear.c (with preprocessing)
+[kernel] Parsing tests/plugin/ast_clear.c (with preprocessing)
diff --git a/src/plugins/instantiate/transform.ml b/src/plugins/instantiate/transform.ml
index 28f7a1ca81145cb2e7b414d21a0218b59ec6905f..c1f0f29d170495ca9c3421cf725d8c3d5c7a8d37 100644
--- a/src/plugins/instantiate/transform.ml
+++ b/src/plugins/instantiate/transform.ml
@@ -29,12 +29,6 @@ let register (module G: Generator_sig) =
   let module Instantiator = Make_instantiator(G) in
   Hashtbl.add base G.function_name (module Instantiator)
 
-let mark_as_computed () =
-  let mark_as_computed _ instantiator =
-    let module I = (val instantiator: Instantiator) in I.mark_as_computed ()
-  in
-  Hashtbl.iter mark_as_computed base
-
 let get_kfs () =
   let get_kfs _ instantiator =
     let module I = (val instantiator: Instantiator) in
@@ -43,6 +37,13 @@ let get_kfs () =
   in
   Hashtbl.fold (fun k v l -> (get_kfs k v) @ l) base []
 
+let clear () =
+  let clear _ instantiator =
+    let module I = (val instantiator: Instantiator) in
+    I.clear ()
+  in
+  Hashtbl.iter clear base
+
 module VISet = Cil_datatype.Varinfo.Hptset
 
 class transformer = object(self)
@@ -55,7 +56,6 @@ class transformer = object(self)
     let post f =
       Ast.mark_as_changed () ;
       Ast.mark_as_grown () ;
-      mark_as_computed () ;
       f
     in
     Cil.DoChildrenPost post
@@ -158,5 +158,6 @@ let compute_statuses_all_kfs () =
   List.iter compute_comp_disj_statuses kfs
 
 let transform file =
+  clear () ;
   Visitor.visitFramacFile (new transformer) file ;
   compute_statuses_all_kfs ()