diff --git a/benchs/run_benchs.ml b/benchs/run_benchs.ml
index 593c8da7..bb7fd23e 100644
--- a/benchs/run_benchs.ml
+++ b/benchs/run_benchs.ml
@@ -1158,7 +1158,7 @@ module Str = struct
   (* random string, but always returns the same for a given size *)
   let rand_str_ ?(among="abcdefgh") n =
     let module Q = Quickcheck in
-    let st = Random.State.make [| n |] in
+    let st = Random.State.make [| n + 17 |] in
     let gen_c = Q.Gen.oneofl (CCString.to_list among) in
     Q.Gen.string_size ~gen:gen_c (Q.Gen.return n) st
 
@@ -1213,11 +1213,15 @@ module Str = struct
     and mk_current = match dir with
       | `Direct -> fun () -> CCString.find ~sub:needle haystack
       | `Reverse -> fun () -> CCString.rfind ~sub:needle haystack
+    and mk_current_compiled = match dir with
+      | `Direct -> let f = CCString.find ~start:0 ~sub:needle in fun () -> f haystack
+      | `Reverse -> let f = CCString.rfind ~sub:needle in fun () -> f haystack
     in
     assert (mk_naive () = mk_current ());
     B.throughputN 3 ~repeat
       [ "naive", mk_naive, ()
       ; "current", mk_current, ()
+      ; "current_compiled", mk_current_compiled, ()
       ]
 
   (* benchmark String.find_all *)
@@ -1226,11 +1230,14 @@ module Str = struct
     let haystack = rand_str_ n in
     pp_pb needle haystack;
     let mk_naive () = find_all_l ~sub:needle haystack
-    and mk_current () = CCString.find_all_l ~sub:needle haystack in
+    and mk_current () = CCString.find_all_l ~sub:needle haystack
+    and mk_current_compiled =
+      let f = CCString.find_all_l ~start:0 ~sub:needle in fun () -> f haystack in
     assert (mk_naive () = mk_current ());
     B.throughputN 3 ~repeat
       [ "naive", mk_naive, ()
       ; "current", mk_current, ()
+      ; "current_compiled", mk_current_compiled, ()
       ]
 
   (* benchmark String.find_all on constant strings *)
@@ -1252,8 +1259,7 @@ module Str = struct
   let () = B.Tree.register (
     "string" @>>>
       [ "find" @>>>
-          [ "1" @>> app_ints (bench_find ~size:1) [100; 100_000; 500_000]
-          ; "3" @>> app_ints (bench_find ~size:3) [100; 100_000; 500_000]
+          [ "3" @>> app_ints (bench_find ~size:3) [100; 100_000; 500_000]
           ; "5" @>> app_ints (bench_find ~size:5) [100; 100_000; 500_000]
           ; "15" @>> app_ints (bench_find ~size:15) [100; 100_000; 500_000]
           ; "50" @>> app_ints (bench_find ~size:50) [100; 100_000; 500_000]
diff --git a/src/core/CCString.cppo.ml b/src/core/CCString.cppo.ml
index ee2ab50b..5c14f724 100644
--- a/src/core/CCString.cppo.ml
+++ b/src/core/CCString.cppo.ml
@@ -75,15 +75,15 @@ type _ direction =
   | Reverse : [`Reverse] direction
 
 (* we follow https://en.wikipedia.org/wiki/Knuth–Morris–Pratt_algorithm *)
-module KMP = struct
-  type 'a pattern = {
+module Find = struct
+  type 'a kmp_pattern = {
     failure : int array;
     str : string;
   }
   (* invariant: [length failure = length str].
    We use a phantom type to avoid mixing the directions. *)
 
-  let pattern_length p = String.length p.str
+  let kmp_pattern_length p = String.length p.str
 
   (* access the [i]-th element of [s] according to direction [dir] *)
   let get_
@@ -92,8 +92,8 @@ module KMP = struct
     | Direct -> String.get
     | Reverse -> (fun s i -> s.[String.length s - i - 1])
 
-  let compile_
-  : type a. dir:a direction -> string -> a pattern
+  let kmp_compile_
+  : type a. dir:a direction -> string -> a kmp_pattern
   = fun ~dir str ->
     let len = length str in
     let get = get_ ~dir in (* how to read elements of the string *)
@@ -127,21 +127,21 @@ module KMP = struct
       (* Format.printf "{@[failure:%a, str:%s@]}@." CCFormat.(array int) failure str; *)
       { failure; str; }
 
-  let compile s = compile_ ~dir:Direct s
-  let rcompile s = compile_ ~dir:Reverse s
+  let kmp_compile s = kmp_compile_ ~dir:Direct s
+  let kmp_rcompile s = kmp_compile_ ~dir:Reverse s
 
   (* proper search function.
     [i] index in [s]
     [j] index in [pattern]
     [len] length of [s] *)
-  let find_
-  : type a. dir:a direction -> pattern:a pattern -> string -> int -> int
+  let kmp_find_
+  : type a. dir:a direction -> pattern:a kmp_pattern -> string -> int -> int
   = fun ~dir ~pattern s idx ->
     let len = length s in
     let get = get_ ~dir in
     let i = ref idx in
     let j = ref 0 in
-    let pat_len = pattern_length pattern in
+    let pat_len = kmp_pattern_length pattern in
     while !j < pat_len && !i + !j < len do
       let c = get s (!i + !j) in
       let expected = get pattern.str !j in
@@ -168,34 +168,63 @@ module KMP = struct
     then !i
     else -1
 
-  let find ~pattern s i = find_ ~dir:Direct ~pattern s i
+  let kmp_find ~pattern s i = kmp_find_ ~dir:Direct ~pattern s i
 
-  let rfind ~pattern s i =
+  let kmp_rfind ~pattern s i =
     let i = String.length s - i - 1 in
-    let res = find_ ~dir:Reverse ~pattern s i in
+    let res = kmp_find_ ~dir:Reverse ~pattern s i in
     (* adjust result: first, [res = string.length s - res -1] to convert
        back to real indices; then, what we got is actually the position
        of the end of the pattern, so we subtract the [length of the pattern -1]
        to obtain the real result. *)
     if res = ~-1
     then res
-    else (String.length s - res) - pattern_length pattern
+    else (String.length s - res) - kmp_pattern_length pattern
+
+  type 'a pattern =
+    | P_char of char
+    | P_KMP of 'a kmp_pattern
+
+  let pattern_length = function
+    | P_char _ -> 1
+    | P_KMP p -> kmp_pattern_length p
+
+  let compile ~sub : [`Direct] pattern =
+    if length sub=1
+    then P_char sub.[0]
+    else P_KMP (kmp_compile sub)
+
+  let rcompile ~sub : [`Reverse] pattern =
+    if length sub=1
+    then P_char sub.[0]
+    else P_KMP (kmp_rcompile sub)
+
+  let find ~pattern s start = match pattern with
+    | P_char c ->
+        (try String.index_from s start c with Not_found -> -1)
+    | P_KMP pattern -> kmp_find ~pattern s start
+
+  let rfind ~pattern s start = match pattern with
+    | P_char c ->
+        (try String.rindex_from s start c with Not_found -> -1)
+    | P_KMP pattern -> kmp_rfind ~pattern s start
 end
 
-let find ?(start=0) ~sub s =
-  let pattern = KMP.compile sub in
-  KMP.find ~pattern s start
+let find ?(start=0) ~sub =
+  let pattern = Find.compile ~sub in
+  fun s -> Find.find ~pattern s start
 
-let find_all ?(start=0) ~sub s =
-  let pattern = KMP.compile sub in
-  let i = ref start in
-  fun () ->
-    let res = KMP.find ~pattern s !i in
-    if res = ~-1 then None
-    else (
-      i := res + KMP.pattern_length pattern;
-      Some res
-    )
+let find_all ?(start=0) ~sub =
+  let pattern = Find.compile ~sub in
+  fun s ->
+    let i = ref start in
+    fun () ->
+      let res = Find.find ~pattern s !i in
+      if res = ~-1 then None
+      else (
+        i := res + Find.pattern_length pattern;
+        Some res
+      )
 
 let find_all_l ?start ~sub s =
   let rec aux acc g = match g () with
@@ -206,9 +235,9 @@ let find_all_l ?start ~sub s =
 
 let mem ?start ~sub s = find ?start ~sub s >= 0
 
-let rfind ~sub s =
-  let pattern = KMP.rcompile sub in
-  KMP.rfind ~pattern s (String.length s-1)
+let rfind ~sub =
+  let pattern = Find.rcompile ~sub in
+  fun s -> Find.rfind ~pattern s (String.length s-1)
 
 (* Replace substring [s.[pos]....s.[pos+len-1]] by [by] in [s] *)
 let replace_at_ ~pos ~len ~by s =
@@ -229,11 +258,11 @@ let replace ?(which=`All) ~sub ~by s =
       if i>=0 then replace_at_ ~pos:i ~len:(String.length sub) ~by s else s
   | `All ->
       (* compile search pattern only once *)
-      let pattern = KMP.compile sub in
+      let pattern = Find.compile ~sub in
       let b = Buffer.create (String.length s) in
       let start = ref 0 in
       while !start < String.length s do
-        let i = KMP.find ~pattern s !start in
+        let i = Find.find ~pattern s !start in
         if i>=0 then (
           (* between last and cur occurrences *)
           Buffer.add_substring b s !start (i- !start);
@@ -256,16 +285,16 @@ module Split = struct
     | SplitStop -> None
     | SplitAt prev -> _split_search ~by s prev
   and _split_search ~by s prev =
-    let j = KMP.find ~pattern:by s prev in
+    let j = Find.find ~pattern:by s prev in
     if j < 0
       then Some (SplitStop, prev, String.length s - prev)
-      else Some (SplitAt (j+KMP.pattern_length by), prev, j-prev)
+      else Some (SplitAt (j+Find.pattern_length by), prev, j-prev)
 
   let _tuple3 x y z = x,y,z
 
   let _mkgen ~by s k =
     let state = ref (SplitAt 0) in
-    let by = KMP.compile by in
+    let by = Find.compile ~sub:by in
     fun () ->
       match _split ~by s !state with
         | None -> None
@@ -278,7 +307,7 @@ module Split = struct
   let gen_cpy ~by s = _mkgen ~by s String.sub
 
   let _mklist ~by s k =
-    let by = KMP.compile by in
+    let by = Find.compile ~sub:by in
     let rec build acc state = match _split ~by s state with
       | None -> List.rev acc
       | Some (state', i, len) ->
@@ -291,7 +320,7 @@ module Split = struct
   let list_cpy ~by s = _mklist ~by s String.sub
 
   let _mkklist ~by s k =
-    let by = KMP.compile by in
+    let by = Find.compile ~sub:by in
     let rec make state () = match _split ~by s state with
       | None -> `Nil
       | Some (state', i, len) ->
@@ -303,7 +332,7 @@ module Split = struct
   let klist_cpy ~by s = _mkklist ~by s String.sub
 
   let _mkseq ~by s f k =
-    let by = KMP.compile by in
+    let by = Find.compile ~sub:by in
     let rec aux state = match _split ~by s state with
       | None -> ()
       | Some (state', i, len) -> k (f s i len); aux state'