Source file TacBittest.ml
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open Lang
let positive e = F.p_leq F.e_zero e
let power k = F.e_bigint (Integer.two_power_of_int k)
let lookup_int e =
let open Qed.Logic in
match F.repr e with
| Kint z -> (try Some (Integer.to_int_exn z) with Z.Overflow -> None)
| _ -> None
let rec lookup_bittest e =
match F.repr e with
| Not e -> lookup_bittest e
| Fun(f,[n;ek]) when List.memq f Cint.f_bits ->
begin
match lookup_int ek with
| Some k when 0 <= k && k < 128 -> Some (n,k)
| _ -> None
end
| _ -> None
class bittestrange =
object
inherit Tactical.make
~id:"Wp.bittestrange"
~title:"Bit-Test Range"
~descr:"Compute bounds with respect to bits."
~params:[]
method select _feedback selection =
let e = Tactical.selected selection in
match lookup_bittest e with
| Some (n,k) ->
let bit = Cint.bit_test n k in
let bit_set = F.p_bool bit in
let bit_clear = F.p_not bit_set in
let pos = positive n in
let pk = power k in
let pk1 = power (succ k) in
let g_inf = F.p_hyps [pos] (F.p_leq pk n) in
let g_sup = F.p_hyps [pos;F.p_lt n pk1] (F.p_lt n pk) in
let name_inf = Printf.sprintf "Bit #%d (inf)" k in
let name_sup = Printf.sprintf "Bit #%d (sup)" k in
let at = Tactical.at selection in
Tactical.Applicable (Tactical.insert ?at [
name_inf , F.p_and bit_set g_inf ;
name_sup , F.p_and bit_clear g_sup ;
])
| None -> Tactical.Not_applicable
end
let tactical = Tactical.export (new bittestrange)
let strategy = Strategy.make tactical ~arguments:[]
let rec lookup push step e =
match F.repr e with
| And es -> List.iter (lookup push step) es
| Or es -> List.iter (lookup push step) es
| Imply (hs,p) -> List.iter (lookup push step) (p::hs)
| _ ->
begin
match lookup_bittest e with
| None -> ()
| Some _ ->
push @@ strategy ~priority:0.3 (Tactical.Inside(step,e))
end
class autobittestrange : Strategy.heuristic =
object
method id = "wp:bittestrange"
method title = "Auto Bit-Test Range"
method descr = "Apply bitwise tactics on bit-tests expressions."
method search push (seq : Conditions.sequent) =
Conditions.iter
(fun step ->
let p = Conditions.head step |> F.e_prop in
lookup push (Tactical.Step step) p
) (fst seq) ;
let p = snd seq in
lookup push (Tactical.Goal p) (F.e_prop p)
end
let () = Strategy.register (new autobittestrange)