Module SplitLong


Instruction selection for 64-bit integer operations

From Coq Require String.
Require Import Coqlib.
Require Import AST Integers Floats.
Require Import Op CminorSel.
Require Import OpHelpers.
Require Import SelectOp.

Local Open Scope cminorsel_scope.
Local Open Scope string_scope.

Section SELECT.

Context {hf: helper_functions}.

Definition makelong (h l: expr): expr :=
  Eop Omakelong (h ::: l ::: Enil).

Original definition: 
Nondetfunction splitlong (e: expr) (f: expr -> expr -> expr) :=
  match e with
  | Eop Omakelong (h ::: l ::: Enil) => f h l
  | _ => Elet e (f (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil)))
  end.

Inductive splitlong_cases: forall (e: expr) , Type :=
  | splitlong_case1: forall h l, splitlong_cases (Eop Omakelong (h ::: l ::: Enil))
  | splitlong_default: forall (e: expr) , splitlong_cases e.

Definition splitlong_match (e: expr) :=
  match e as zz1 return splitlong_cases zz1 with
  | Eop Omakelong (h ::: l ::: Enil) => splitlong_case1 h l
  | e => splitlong_default e
  end.

Definition splitlong (e: expr) (f: expr -> expr -> expr) :=
  match splitlong_match e with
  | splitlong_case1 h l =>
      f h l
  | splitlong_default e =>
      Elet e (f (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil)))
  end.


Original definition: 
Nondetfunction splitlong2 (e1 e2: expr) (f: expr -> expr -> expr -> expr -> expr) :=
  match e1, e2 with
  | Eop Omakelong (h1 ::: l1 ::: Enil), Eop Omakelong (h2 ::: l2 ::: Enil) =>
      f h1 l1 h2 l2
  | Eop Omakelong (h1 ::: l1 ::: Enil), t2 =>
      Elet t2 (f (lift h1) (lift l1)
                 (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil)))
  | t1, Eop Omakelong (h2 ::: l2 ::: Enil) =>
      Elet t1 (f (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil))
                 (lift h2) (lift l2))
  | _, _ =>
      Elet e1 (Elet (lift e2)
        (f (Eop Ohighlong (Eletvar 1 ::: Enil)) (Eop Olowlong (Eletvar 1 ::: Enil))
           (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil))))
  end.

Inductive splitlong2_cases: forall (e1 e2: expr) , Type :=
  | splitlong2_case1: forall h1 l1 h2 l2, splitlong2_cases (Eop Omakelong (h1 ::: l1 ::: Enil)) (Eop Omakelong (h2 ::: l2 ::: Enil))
  | splitlong2_case2: forall h1 l1 t2, splitlong2_cases (Eop Omakelong (h1 ::: l1 ::: Enil)) (t2)
  | splitlong2_case3: forall t1 h2 l2, splitlong2_cases (t1) (Eop Omakelong (h2 ::: l2 ::: Enil))
  | splitlong2_default: forall (e1 e2: expr) , splitlong2_cases e1 e2.

Definition splitlong2_match (e1 e2: expr) :=
  match e1 as zz1, e2 as zz2 return splitlong2_cases zz1 zz2 with
  | Eop Omakelong (h1 ::: l1 ::: Enil), Eop Omakelong (h2 ::: l2 ::: Enil) => splitlong2_case1 h1 l1 h2 l2
  | Eop Omakelong (h1 ::: l1 ::: Enil), t2 => splitlong2_case2 h1 l1 t2
  | t1, Eop Omakelong (h2 ::: l2 ::: Enil) => splitlong2_case3 t1 h2 l2
  | e1, e2 => splitlong2_default e1 e2
  end.

Definition splitlong2 (e1 e2: expr) (f: expr -> expr -> expr -> expr -> expr) :=
  match splitlong2_match e1 e2 with
  | splitlong2_case1 h1 l1 h2 l2 =>
      f h1 l1 h2 l2
  | splitlong2_case2 h1 l1 t2 =>
      Elet t2 (f (lift h1) (lift l1) (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil)))
  | splitlong2_case3 t1 h2 l2 =>
      Elet t1 (f (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil)) (lift h2) (lift l2))
  | splitlong2_default e1 e2 =>
      Elet e1 (Elet (lift e2) (f (Eop Ohighlong (Eletvar 1 ::: Enil)) (Eop Olowlong (Eletvar 1 ::: Enil)) (Eop Ohighlong (Eletvar O ::: Enil)) (Eop Olowlong (Eletvar O ::: Enil))))
  end.


Original definition: 
Nondetfunction lowlong (e: expr) :=
  match e with
  | Eop Omakelong (e1 ::: e2 ::: Enil) => e2
  | _ => Eop Olowlong (e ::: Enil)
  end.

Inductive lowlong_cases: forall (e: expr), Type :=
  | lowlong_case1: forall e1 e2, lowlong_cases (Eop Omakelong (e1 ::: e2 ::: Enil))
  | lowlong_default: forall (e: expr), lowlong_cases e.

Definition lowlong_match (e: expr) :=
  match e as zz1 return lowlong_cases zz1 with
  | Eop Omakelong (e1 ::: e2 ::: Enil) => lowlong_case1 e1 e2
  | e => lowlong_default e
  end.

Definition lowlong (e: expr) :=
  match lowlong_match e with
  | lowlong_case1 e1 e2 =>
      e2
  | lowlong_default e =>
      Eop Olowlong (e ::: Enil)
  end.


Original definition: 
Nondetfunction highlong (e: expr) :=
  match e with
  | Eop Omakelong (e1 ::: e2 ::: Enil) => e1
  | _ => Eop Ohighlong (e ::: Enil)
  end.

Inductive highlong_cases: forall (e: expr), Type :=
  | highlong_case1: forall e1 e2, highlong_cases (Eop Omakelong (e1 ::: e2 ::: Enil))
  | highlong_default: forall (e: expr), highlong_cases e.

Definition highlong_match (e: expr) :=
  match e as zz1 return highlong_cases zz1 with
  | Eop Omakelong (e1 ::: e2 ::: Enil) => highlong_case1 e1 e2
  | e => highlong_default e
  end.

Definition highlong (e: expr) :=
  match highlong_match e with
  | highlong_case1 e1 e2 =>
      e1
  | highlong_default e =>
      Eop Ohighlong (e ::: Enil)
  end.


Definition longconst (n: int64) : expr :=
  makelong (Eop (Ointconst (Int64.hiword n)) Enil)
           (Eop (Ointconst (Int64.loword n)) Enil).

Original definition: 
Nondetfunction is_longconst (e: expr) :=
  match e with
  | Eop Omakelong (Eop (Ointconst h) Enil ::: Eop (Ointconst l) Enil ::: Enil) =>
      Some(Int64.ofwords h l)
  | _ =>
      None
  end.

Inductive is_longconst_cases: forall (e: expr), Type :=
  | is_longconst_case1: forall h l, is_longconst_cases (Eop Omakelong (Eop (Ointconst h) Enil ::: Eop (Ointconst l) Enil ::: Enil))
  | is_longconst_default: forall (e: expr), is_longconst_cases e.

Definition is_longconst_match (e: expr) :=
  match e as zz1 return is_longconst_cases zz1 with
  | Eop Omakelong (Eop (Ointconst h) Enil ::: Eop (Ointconst l) Enil ::: Enil) => is_longconst_case1 h l
  | e => is_longconst_default e
  end.

Definition is_longconst (e: expr) :=
  match is_longconst_match e with
  | is_longconst_case1 h l =>
      Some(Int64.ofwords h l)
  | is_longconst_default e =>
      None
  end.


Definition is_longconst_zero (e: expr) :=
  match is_longconst e with
  | Some n => Int64.eq n Int64.zero
  | None => false
  end.

Definition intoflong (e: expr) := lowlong e.

Original definition: 
Nondetfunction longofint (e: expr) :=
  match e with
  | Eop (Ointconst n) Enil => longconst (Int64.repr (Int.signed n))
  | _ => Elet e (makelong (shrimm (Eletvar O) (Int.repr 31)) (Eletvar O))
  end.

Inductive longofint_cases: forall (e: expr), Type :=
  | longofint_case1: forall n, longofint_cases (Eop (Ointconst n) Enil)
  | longofint_default: forall (e: expr), longofint_cases e.

Definition longofint_match (e: expr) :=
  match e as zz1 return longofint_cases zz1 with
  | Eop (Ointconst n) Enil => longofint_case1 n
  | e => longofint_default e
  end.

Definition longofint (e: expr) :=
  match longofint_match e with
  | longofint_case1 n =>
      longconst (Int64.repr (Int.signed n))
  | longofint_default e =>
      Elet e (makelong (shrimm (Eletvar O) (Int.repr 31)) (Eletvar O))
  end.


Definition longofintu (e: expr) :=
  makelong (Eop (Ointconst Int.zero) Enil) e.

Definition negl (e: expr) :=
  match is_longconst e with
  | Some n => longconst (Int64.neg n)
  | None => Ebuiltin (EF_builtin "__builtin_negl" sig_l_l) (e ::: Enil)
  end.

Definition notl (e: expr) :=
  splitlong e (fun h l => makelong (notint h) (notint l)).

Definition longoffloat (arg: expr) :=
  Eexternal (QualIdent.root i64_dtos) sig_f_l (arg ::: Enil).
Definition longuoffloat (arg: expr) :=
  Eexternal (QualIdent.root i64_dtou) sig_f_l (arg ::: Enil).
Definition floatoflong (arg: expr) :=
  Eexternal (QualIdent.root i64_stod) sig_l_f (arg ::: Enil).
Definition floatoflongu (arg: expr) :=
  Eexternal (QualIdent.root i64_utod) sig_l_f (arg ::: Enil).
Definition longofsingle (arg: expr) :=
  longoffloat (floatofsingle arg).
Definition longuofsingle (arg: expr) :=
  longuoffloat (floatofsingle arg).
Definition singleoflong (arg: expr) :=
  Eexternal (QualIdent.root i64_stof) sig_l_s (arg ::: Enil).
Definition singleoflongu (arg: expr) :=
  Eexternal (QualIdent.root i64_utof) sig_l_s (arg ::: Enil).

Definition andl (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 => makelong (and h1 h2) (and l1 l2)).

Definition orl (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 => makelong (or h1 h2) (or l1 l2)).

Definition xorl (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 => makelong (xor h1 h2) (xor l1 l2)).

Definition shllimm (e1: expr) (n: int) :=
  if Int.eq n Int.zero then e1 else
  if Int.ltu n Int.iwordsize then
   splitlong e1 (fun h l =>
     makelong (or (shlimm h n) (shruimm l (Int.sub Int.iwordsize n)))
              (shlimm l n))
  else if Int.ltu n Int64.iwordsize' then
    makelong (shlimm (lowlong e1) (Int.sub n Int.iwordsize))
             (Eop (Ointconst Int.zero) Enil)
  else
    Eexternal (QualIdent.root i64_shl) sig_li_l (e1 ::: Eop (Ointconst n) Enil ::: Enil).

Definition shrluimm (e1: expr) (n: int) :=
  if Int.eq n Int.zero then e1 else
  if Int.ltu n Int.iwordsize then
    splitlong e1 (fun h l =>
      makelong (shruimm h n)
               (or (shruimm l n) (shlimm h (Int.sub Int.iwordsize n))))
  else if Int.ltu n Int64.iwordsize' then
    makelong (Eop (Ointconst Int.zero) Enil)
             (shruimm (highlong e1) (Int.sub n Int.iwordsize))
  else
    Eexternal (QualIdent.root i64_shr) sig_li_l (e1 ::: Eop (Ointconst n) Enil ::: Enil).

Definition shrlimm (e1: expr) (n: int) :=
  if Int.eq n Int.zero then e1 else
  if Int.ltu n Int.iwordsize then
    splitlong e1 (fun h l =>
      makelong (shrimm h n)
               (or (shruimm l n) (shlimm h (Int.sub Int.iwordsize n))))
  else if Int.ltu n Int64.iwordsize' then
    Elet (highlong e1)
      (makelong (shrimm (Eletvar 0) (Int.repr 31))
                (shrimm (Eletvar 0) (Int.sub n Int.iwordsize)))
  else
    Eexternal (QualIdent.root i64_sar) sig_li_l (e1 ::: Eop (Ointconst n) Enil ::: Enil).

Definition is_intconst (e: expr) :=
  match e with
  | Eop (Ointconst n) Enil => Some n
  | _ => None
  end.

Definition shll (e1 e2: expr) :=
  match is_intconst e2 with
  | Some n => shllimm e1 n
  | None => Eexternal (QualIdent.root i64_shl) sig_li_l (e1 ::: e2 ::: Enil)
  end.

Definition shrlu (e1 e2: expr) :=
  match is_intconst e2 with
  | Some n => shrluimm e1 n
  | None => Eexternal (QualIdent.root i64_shr) sig_li_l (e1 ::: e2 ::: Enil)
  end.

Definition shrl (e1 e2: expr) :=
  match is_intconst e2 with
  | Some n => shrlimm e1 n
  | None => Eexternal (QualIdent.root i64_sar) sig_li_l (e1 ::: e2 ::: Enil)
  end.

Definition addl (e1 e2: expr) :=
  let default := Ebuiltin (EF_builtin "__builtin_addl" sig_ll_l) (e1 ::: e2 ::: Enil) in
  match is_longconst e1, is_longconst e2 with
  | Some n1, Some n2 => longconst (Int64.add n1 n2)
  | Some n1, _ => if Int64.eq n1 Int64.zero then e2 else default
  | _, Some n2 => if Int64.eq n2 Int64.zero then e1 else default
  | _, _ => default
  end.

Definition subl (e1 e2: expr) :=
  let default := Ebuiltin (EF_builtin "__builtin_subl" sig_ll_l) (e1 ::: e2 ::: Enil) in
  match is_longconst e1, is_longconst e2 with
  | Some n1, Some n2 => longconst (Int64.sub n1 n2)
  | Some n1, _ => if Int64.eq n1 Int64.zero then negl e2 else default
  | _, Some n2 => if Int64.eq n2 Int64.zero then e1 else default
  | _, _ => default
  end.

Definition mull_base (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 =>
    Elet (Ebuiltin (EF_builtin "__builtin_mull" sig_ii_l) (l1 ::: l2 ::: Enil))
      (makelong
        (add (add (Eop Ohighlong (Eletvar O ::: Enil))
                  (mul (lift l1) (lift h2)))
             (mul (lift h1) (lift l2)))
        (Eop Olowlong (Eletvar O ::: Enil)))).

Definition mullimm (n: int64) (e: expr) :=
  if Int64.eq n Int64.zero then longconst Int64.zero else
  if Int64.eq n Int64.one then e else
  match Int64.is_power2' n with
  | Some l => shllimm e l
  | None => mull_base e (longconst n)
  end.

Definition mull (e1 e2: expr) :=
  match is_longconst e1, is_longconst e2 with
  | Some n1, Some n2 => longconst (Int64.mul n1 n2)
  | Some n1, _ => mullimm n1 e2
  | _, Some n2 => mullimm n2 e1
  | _, _ => mull_base e1 e2
  end.

Definition mullhu (e1: expr) (n2: int64) :=
  Eexternal (QualIdent.root i64_umulh) sig_ll_l (e1 ::: longconst n2 ::: Enil).
Definition mullhs (e1: expr) (n2: int64) :=
  Eexternal (QualIdent.root i64_smulh) sig_ll_l (e1 ::: longconst n2 ::: Enil).

Definition shrxlimm (e: expr) (n: int) :=
  if Int.eq n Int.zero then e else
    Elet e (shrlimm (addl (Eletvar O)
                          (shrluimm (shrlimm (Eletvar O) (Int.repr 63))
                                    (Int.sub (Int.repr 64) n)))
                    n).

Definition divlu_base (e1 e2: expr) := Eexternal (QualIdent.root i64_udiv) sig_ll_l (e1 ::: e2 ::: Enil).
Definition modlu_base (e1 e2: expr) := Eexternal (QualIdent.root i64_umod) sig_ll_l (e1 ::: e2 ::: Enil).
Definition divls_base (e1 e2: expr) := Eexternal (QualIdent.root i64_sdiv) sig_ll_l (e1 ::: e2 ::: Enil).
Definition modls_base (e1 e2: expr) := Eexternal (QualIdent.root i64_smod) sig_ll_l (e1 ::: e2 ::: Enil).

Definition cmpl_eq_zero (e: expr) :=
  splitlong e (fun h l => comp Ceq (or h l) (Eop (Ointconst Int.zero) Enil)).

Definition cmpl_ne_zero (e: expr) :=
  splitlong e (fun h l => comp Cne (or h l) (Eop (Ointconst Int.zero) Enil)).

Definition cmplu_gen (ch cl: comparison) (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 =>
    Econdition (CEcond (Ccomp Ceq) None (h1:::h2:::Enil))
               (Eop (Ocmp (Ccompu cl)) (l1:::l2:::Enil))
               (Eop (Ocmp (Ccompu ch)) (h1:::h2:::Enil))).

Definition cmplu (c: comparison) (e1 e2: expr) :=
  match c with
  | Ceq =>
      cmpl_eq_zero (xorl e1 e2)
  | Cne =>
      cmpl_ne_zero (xorl e1 e2)
  | Clt =>
      cmplu_gen Clt Clt e1 e2
  | Cle =>
      cmplu_gen Clt Cle e1 e2
  | Cgt =>
      cmplu_gen Cgt Cgt e1 e2
  | Cge =>
      cmplu_gen Cgt Cge e1 e2
  end.

Definition cmpl_gen (ch cl: comparison) (e1 e2: expr) :=
  splitlong2 e1 e2 (fun h1 l1 h2 l2 =>
    Econdition (CEcond (Ccomp Ceq) None (h1:::h2:::Enil))
               (Eop (Ocmp (Ccompu cl)) (l1:::l2:::Enil))
               (Eop (Ocmp (Ccomp ch)) (h1:::h2:::Enil))).

Definition cmpl (c: comparison) (e1 e2: expr) :=
  match c with
  | Ceq =>
      cmpl_eq_zero (xorl e1 e2)
  | Cne =>
      cmpl_ne_zero (xorl e1 e2)
  | Clt =>
      if is_longconst_zero e2
      then comp Clt (highlong e1) (Eop (Ointconst Int.zero) Enil)
      else cmpl_gen Clt Clt e1 e2
  | Cle =>
      cmpl_gen Clt Cle e1 e2
  | Cgt =>
      cmpl_gen Cgt Cgt e1 e2
  | Cge =>
      if is_longconst_zero e2
      then comp Cge (highlong e1) (Eop (Ointconst Int.zero) Enil)
      else cmpl_gen Cgt Cge e1 e2
  end.

Definition select_long (cond: condition) (args: exprlist) (e1 e2: expr) :=
  if select_supported Tlong then
    select Tlong cond args e1 e2
  else
    bind_exprs (e1 ::: e2 ::: args) (fun al =>
      match al with
      | e1 ::: e2 ::: args =>
          makelong
            (select Tint cond args (Eop Ohighlong (e1 ::: Enil)) (Eop Ohighlong (e2 ::: Enil)))
            (select Tint cond args (Eop Olowlong (e1 ::: Enil)) (Eop Olowlong (e2 ::: Enil)))

      | _ => longconst Int64.zero
      end).

End SELECT.
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