Module ConstpropOpproof

Require Import Coqlib Compopts.
Require Import Integers Floats Values Memory Globalenvs Events.
Require Import Op Registers RTL ValueDomain.
Require Import ConstpropOp.
Require Import Lia.

Section STRENGTH_REDUCTION.

Variable bc: block_classification.
Variable ge: genv.
Hypothesis GENV: genv_match bc ge.
Variable sp: block.
Hypothesis STACK: bc sp = BCstack.
Variable ae: AE.t.
Variable e: regset.
Variable m: mem.
Hypothesis MATCH: ematch bc e ae.

Lemma match_G:
  forall r id ofs,
  AE.get r ae = Ptr(Gl id ofs) -> Val.lessdef e#r (Genv.symbol_address ge id ofs).

Lemma match_S:
  forall r ofs,
  AE.get r ae = Ptr(Stk ofs) -> Val.lessdef e#r (Vptr sp ofs).

Ltac InvApproxRegs :=
  match goal with
  | [ H: _ :: _ = _ :: _ |- _ ] =>
        injection H; clear H; intros; InvApproxRegs
  | [ H: ?v = AE.get ?r ae |- _ ] =>
        generalize (MATCH r); rewrite <- H; clear H; intro; InvApproxRegs
  | _ => idtac
  end.

Ltac SimplVM :=
  match goal with
  | [ H: vmatch _ ?v (I ?n) |- _ ] =>
      let E := fresh in
      assert (E: v = Vint n) by (inversion H; auto);
      rewrite E in *; clear H; SimplVM
  | [ H: vmatch _ ?v (L ?n) |- _ ] =>
      let E := fresh in
      assert (E: v = Vlong n) by (inversion H; auto);
      rewrite E in *; clear H; SimplVM
  | [ H: vmatch _ ?v (F ?n) |- _ ] =>
      let E := fresh in
      assert (E: v = Vfloat n) by (inversion H; auto);
      rewrite E in *; clear H; SimplVM
  | [ H: vmatch _ ?v (FS ?n) |- _ ] =>
      let E := fresh in
      assert (E: v = Vsingle n) by (inversion H; auto);
      rewrite E in *; clear H; SimplVM
  | [ H: vmatch _ ?v (Ptr(Gl ?id ?ofs)) |- _ ] =>
      let E := fresh in
      assert (E: Val.lessdef v (Genv.symbol_address ge id ofs)) by (eapply vmatch_ptr_gl; eauto);
      clear H; SimplVM
  | [ H: vmatch _ ?v (Ptr(Stk ?ofs)) |- _ ] =>
      let E := fresh in
      assert (E: Val.lessdef v (Vptr sp ofs)) by (eapply vmatch_ptr_stk; eauto);
      clear H; SimplVM
  | _ => idtac
  end.

Lemma const_for_result_correct:
  forall a op v,
  const_for_result a = Some op ->
  vmatch bc v a ->
  exists v', eval_operation ge (Vptr sp Ptrofs.zero) op nil m = Some v' /\ Val.lessdef v v'.

Lemma cond_strength_reduction_correct:
  forall cond args vl,
  vl = map (fun r => AE.get r ae) args ->
  let (cond', args') := cond_strength_reduction cond args vl in
  eval_condition cond' e##args' m = eval_condition cond e##args m.

Lemma make_cmp_base_correct:
  forall c args vl,
  vl = map (fun r => AE.get r ae) args ->
  let (op', args') := make_cmp_base c args vl in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op' e##args' m = Some v
         /\ Val.lessdef (Val.of_optbool (eval_condition c e##args m)) v.

Lemma make_cmp_correct:
  forall c args vl,
  vl = map (fun r => AE.get r ae) args ->
  let (op', args') := make_cmp c args vl in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op' e##args' m = Some v
         /\ Val.lessdef (Val.of_optbool (eval_condition c e##args m)) v.

Lemma make_addimm_correct:
  forall n r,
  let (op, args) := make_addimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.add e#r (Vint n)) v.

Lemma make_shlimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shlimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shl e#r1 (Vint n)) v.

Lemma make_shrimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shrimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shr e#r1 (Vint n)) v.

Lemma make_shruimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shruimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shru e#r1 (Vint n)) v.

Lemma make_mulimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_mulimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mul e#r1 (Vint n)) v.

Lemma make_divimm_correct:
  forall n r1 r2 v,
  Val.divs e#r1 e#r2 = Some v ->
  e#r2 = Vint n ->
  let (op, args) := make_divimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_divuimm_correct:
  forall n r1 r2 v,
  Val.divu e#r1 e#r2 = Some v ->
  e#r2 = Vint n ->
  let (op, args) := make_divuimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_moduimm_correct:
  forall n r1 r2 v,
  Val.modu e#r1 e#r2 = Some v ->
  e#r2 = Vint n ->
  let (op, args) := make_moduimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_andimm_correct:
  forall n r x,
  vmatch bc e#r x ->
  let (op, args) := make_andimm n r x in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.and e#r (Vint n)) v.

Lemma make_orimm_correct:
  forall n r,
  let (op, args) := make_orimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.or e#r (Vint n)) v.

Lemma make_xorimm_correct:
  forall n r,
  let (op, args) := make_xorimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.xor e#r (Vint n)) v.

Lemma make_addlimm_correct:
  forall n r,
  let (op, args) := make_addlimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.addl e#r (Vlong n)) v.

Lemma make_shllimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shllimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shll e#r1 (Vint n)) v.

Lemma make_shrlimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shrlimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shrl e#r1 (Vint n)) v.

Lemma make_shrluimm_correct:
  forall n r1 r2,
  e#r2 = Vint n ->
  let (op, args) := make_shrluimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.shrlu e#r1 (Vint n)) v.

Lemma make_mullimm_correct:
  forall n r1 r2,
  e#r2 = Vlong n ->
  let (op, args) := make_mullimm n r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mull e#r1 (Vlong n)) v.

Lemma make_divlimm_correct:
  forall n r1 r2 v,
  Val.divls e#r1 e#r2 = Some v ->
  e#r2 = Vlong n ->
  let (op, args) := make_divlimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_divluimm_correct:
  forall n r1 r2 v,
  Val.divlu e#r1 e#r2 = Some v ->
  e#r2 = Vlong n ->
  let (op, args) := make_divluimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_modluimm_correct:
  forall n r1 r2 v,
  Val.modlu e#r1 e#r2 = Some v ->
  e#r2 = Vlong n ->
  let (op, args) := make_modluimm n r1 r2 in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some w /\ Val.lessdef v w.

Lemma make_andlimm_correct:
  forall n r x,
  let (op, args) := make_andlimm n r x in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.andl e#r (Vlong n)) v.

Lemma make_orlimm_correct:
  forall n r,
  let (op, args) := make_orlimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.orl e#r (Vlong n)) v.

Lemma make_xorlimm_correct:
  forall n r,
  let (op, args) := make_xorlimm n r in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.xorl e#r (Vlong n)) v.

Lemma make_mulfimm_correct:
  forall n r1 r2,
  e#r2 = Vfloat n ->
  let (op, args) := make_mulfimm n r1 r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mulf e#r1 e#r2) v.

Lemma make_mulfimm_correct_2:
  forall n r1 r2,
  e#r1 = Vfloat n ->
  let (op, args) := make_mulfimm n r2 r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mulf e#r1 e#r2) v.

Lemma make_mulfsimm_correct:
  forall n r1 r2,
  e#r2 = Vsingle n ->
  let (op, args) := make_mulfsimm n r1 r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mulfs e#r1 e#r2) v.

Lemma make_mulfsimm_correct_2:
  forall n r1 r2,
  e#r1 = Vsingle n ->
  let (op, args) := make_mulfsimm n r2 r1 r2 in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.mulfs e#r1 e#r2) v.

Lemma make_cast8signed_correct:
  forall r x,
  vmatch bc e#r x ->
  let (op, args) := make_cast8signed r x in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.sign_ext 8 e#r) v.

Lemma make_cast16signed_correct:
  forall r x,
  vmatch bc e#r x ->
  let (op, args) := make_cast16signed r x in
  exists v, eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v /\ Val.lessdef (Val.sign_ext 16 e#r) v.

Lemma op_strength_reduction_correct:
  forall op args vl v,
  vl = map (fun r => AE.get r ae) args ->
  eval_operation ge (Vptr sp Ptrofs.zero) op e##args m = Some v ->
  let (op', args') := op_strength_reduction op args vl in
  exists w, eval_operation ge (Vptr sp Ptrofs.zero) op' e##args' m = Some w /\ Val.lessdef v w.

Lemma addr_strength_reduction_correct:
  forall addr args vl res,
  vl = map (fun r => AE.get r ae) args ->
  eval_addressing ge (Vptr sp Ptrofs.zero) addr e##args = Some res ->
  let (addr', args') := addr_strength_reduction addr args vl in
  exists res', eval_addressing ge (Vptr sp Ptrofs.zero) addr' e##args' = Some res' /\ Val.lessdef res res'.

End STRENGTH_REDUCTION.