diff --git a/tools/logState.ml b/tools/logState.ml
index cbd25a6a38..94d364e4b9 100644
--- a/tools/logState.ml
+++ b/tools/logState.ml
@@ -224,15 +224,18 @@ let empty_sts = { p_nouts = Int64.zero ; p_sts = []; }
 
 let pretty_bd loc v = pretty_binding loc v ^ ";"
 
+let pp_st st =
+  let e,f,a = st_as_string st in
+  let pp_e = List.map (fun (loc,v) -> pretty_bd loc v) e
+  and pp_f = f
+  and pp_a = List.map (sprintf "~%s") a in
+  String.concat " " (pp_e @ pp_f @ pp_a )
+
 let pretty_state pref mode with_noccs st =
   let buff = Buffer.create 10 in
   Buffer.add_string buff pref ;
   Buffer.add_char buff '[' ;
-  let e,f,a = st_as_string st.p_st in
-  let pp_e = List.map (fun (loc,v) -> pretty_bd loc v) e
-  and pp_f = f
-  and pp_a = List.map (sprintf "~%s") a in
-  let pp = String.concat " " (pp_e @ pp_f @ pp_a ) in
+  let pp = pp_st st.p_st in
   Buffer.add_string buff pp ;
   Buffer.add_char buff ']' ;
   if with_noccs then begin
@@ -349,6 +352,11 @@ let mismatch s =
   let loc,_ = HashedBinding.as_t s in
   raise (StateMismatch loc)
 
+let compare_bindings p1 p2 =
+  match HashedBinding.compare_loc p1 p2 with
+  | 0 -> HashedBinding.compare_v p1 p2
+  | r -> mismatch (if r > 0 then p2 else p1)
+
 let rec compare_env st1 st2 =
   let open Hashcons in
   let open HashedEnv in
@@ -357,14 +365,9 @@ let rec compare_env st1 st2 =
   | (Nil,Cons (p,_))
   | (Cons (p,_),Nil) -> mismatch p
   | Cons (p1,st1),Cons (p2,st2) ->
-      match HashedBinding.compare_loc p1 p2 with
-      | 0 ->
-          begin match HashedBinding.compare_v p1 p2 with
-          | 0 -> compare_env st1 st2
-          | r -> r
-          end
-      | r ->
-          mismatch (if r > 0 then p2 else p1)
+      match compare_bindings p1 p2 with
+      | 0 -> compare_env st1 st2
+      | r -> r
 
 (* Check bindings only *)
 
@@ -409,20 +412,20 @@ let diff_faults sts1 sts2 =
     sts1
 
 let cmp_by_env sts1 sts2 =
-    match sts1,sts2 with
-    | st1::_,st2::_ -> compare_state_by_env st1 st2
-    | _,_ -> assert false
+  match sts1,sts2 with
+  | st1::_,st2::_ -> compare_state_by_env st1 st2
+  | _,_ -> assert false
 
 let do_diff_states =
   let rec diff stss1 stss2 =
     match stss1,stss2 with
     | (_,[])|([],_) -> List.concat stss1
-    | sts1::stss1,sts2::stss2 ->
+    | sts1::r1,sts2::r2 ->
        let r = cmp_by_env sts1 sts2 in
-       if r < 0 then sts1@diff stss1 (sts2::stss2)
-       else if r > 0 then diff stss1 (sts2::stss2)
+       if r < 0 then sts1@diff r1 stss2
+       else if r > 0 then diff stss1 r2
        else
-         diff_faults sts1 sts2@diff stss1 stss2 in
+         diff_faults sts1 sts2@diff r1 r2 in
   fun sts1 sts2 ->
     diff (group_by_env sts1) (group_by_env sts2)
 
diff --git a/tools/tests/mcompare.t/NEW.01 b/tools/tests/mcompare.t/NEW.01
new file mode 100644
index 0000000000..62c173901e
--- /dev/null
+++ b/tools/tests/mcompare.t/NEW.01
@@ -0,0 +1,14 @@
+Test R3+W+32 Allow
+Histogram (5 states)
+769612764:> 0:X1=1; 0:X2=1; 0:X3=1;
+114     :> 0:X1=1; 0:X2=1; 0:X3=2;
+78      :> 0:X1=1; 0:X2=2; 0:X3=2;
+1       :> 0:X1=2; 0:X2=2; 0:X3=1;
+387043  :> 0:X1=2; 0:X2=2; 0:X3=2;
+No
+Witnesses
+Positive: 0 Negative: 770000000
+Condition exists (0:X1=1 /\ 0:X2=2 /\ 0:X3=1) is not validated
+Hash=89712cfbdd33d2386352a5422ece65f8
+Time R3+W+32 771.12
+
diff --git a/tools/tests/mcompare.t/OLD.01 b/tools/tests/mcompare.t/OLD.01
new file mode 100644
index 0000000000..1dd20e8794
--- /dev/null
+++ b/tools/tests/mcompare.t/OLD.01
@@ -0,0 +1,15 @@
+Test R3+W+32 Allow
+Histogram (6 states)
+8396307392:> 0:X1=1; 0:X2=1; 0:X3=1;
+124     :> 0:X1=1; 0:X2=1; 0:X3=2;
+3       :> 0:X1=1; 0:X2=2; 0:X3=1;
+2323034 :> 0:X1=1; 0:X2=2; 0:X3=2;
+5       :> 0:X1=2; 0:X2=1; 0:X3=1;
+163769442:> 0:X1=2; 0:X2=2; 0:X3=2;
+Ok
+Witnesses
+Positive: 3 Negative: 8562399997
+Condition exists (0:X1=1 /\ 0:X2=2 /\ 0:X3=1) is validated
+Hash=89712cfbdd33d2386352a5422ece65f8
+Time R3+W+32 16030.74
+
diff --git a/tools/tests/mcompare.t/run.t b/tools/tests/mcompare.t/run.t
index ff1ba2943a..f6b5220de0 100644
--- a/tools/tests/mcompare.t/run.t
+++ b/tools/tests/mcompare.t/run.t
@@ -44,3 +44,18 @@ Negative faults do not intervene in state comparisons
    |Ok   |                              
   
   $ mcmp7 xxx.log yyy.log
+State diff on complete logs was wrong.
+  $ mcompare7 OLD.01 NEW.01
+  *Diffs*
+         |Kind | OLD.01                    NEW.01                    
+  -------------------------------------------------------------------
+  -------------------------------------------------------------------
+  R3+W+32|Allow| [0:X1=1; 0:X2=1; 0:X3=1;] +[0:X1=2; 0:X2=2; 0:X3=1;]
+         |Ok   | [0:X1=1; 0:X2=1; 0:X3=2;] -[0:X1=1; 0:X2=2; 0:X3=1;]
+         |     | [0:X1=1; 0:X2=2; 0:X3=1;] -[0:X1=2; 0:X2=1; 0:X3=1;]
+         |     | [0:X1=1; 0:X2=2; 0:X3=2;]                           
+         |     | [0:X1=2; 0:X2=1; 0:X3=1;]                           
+         |     | [0:X1=2; 0:X2=2; 0:X3=2;]                           
+  
+  !!! Warning positive differences in: +R3+W+32
+  !!! Warning negative differences in: -R3+W+32