-- Mathlib/.lake/packages/lean4/src/lean/Std/Tactic/BVDecide/Bitblast/BVExpr/Circuit/Lemmas/Operations/Udiv.lean
theorem denote_blastDivSubtractShift_q (aig : AIG α) (assign : α → Bool) (lhs rhs : BitVec w)
    (falseRef trueRef : AIG.Ref aig) (n d : AIG.RefVec aig w) (wn wr : Nat)
    (q r : AIG.RefVec aig w) (qbv rbv : BitVec w)
    (hleft : ∀ (idx : Nat) (hidx : idx < w), ⟦aig, n.get idx hidx, assign⟧ = lhs.getLsbD idx)
    (hright : ∀ (idx : Nat) (hidx : idx < w), ⟦aig, d.get idx hidx, assign⟧ = rhs.getLsbD idx)
    (hq : ∀ (idx : Nat) (hidx : idx < w), ⟦aig, q.get idx hidx, assign⟧ = qbv.getLsbD idx)
    (hr : ∀ (idx : Nat) (hidx : idx < w), ⟦aig, r.get idx hidx, assign⟧ = rbv.getLsbD idx)
    (hfalse : ⟦aig, falseRef, assign⟧ = false)
    (htrue : ⟦aig, trueRef, assign⟧ = true)
      :
    ∀ (idx : Nat) (hidx : idx < w),
      ⟦
        (blastDivSubtractShift aig falseRef trueRef n d wn wr q r).aig,
        (blastDivSubtractShift aig falseRef trueRef n d wn wr q r).q.get idx hidx,
        assign
      ⟧
        =
      (BitVec.divSubtractShift { n := lhs, d := rhs } { wn := wn, wr := wr, q := qbv, r := rbv }).q.getLsbD idx

Proof state:
α : Type
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
assign : α → Bool
lhs rhs : BitVec w
falseRef trueRef : aig.Ref
n d : aig.RefVec w
wn wr : Nat
q r : aig.RefVec w
qbv rbv : BitVec w
hleft : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := n.get idx hidx }⟧ = lhs.getLsbD idx
hright : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := d.get idx hidx }⟧ = rhs.getLsbD idx
hq : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := q.get idx hidx }⟧ = qbv.getLsbD idx
hr : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := r.get idx hidx }⟧ = rbv.getLsbD idx
hfalse : ⟦assign, { aig := aig, ref := falseRef }⟧ = false
htrue : ⟦assign, { aig := aig, ref := trueRef }⟧ = true
idx : Nat
hidx : idx < w
⊢ ⟦assign,
      {
        aig :=
          (RefVec.ite
              (BVPred.mkUlt
                  (blastSub
                      (blastShiftConcat
                          (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                              { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                          { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                      { lhs := ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                        rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                  {
                    lhs :=
                      (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast ⋯,
                    rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
              {
                discr :=
                  (BVPred.mkUlt
                      (blastSub
                          (blastShiftConcat
                              (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                              { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                          {
                            lhs :=
                              ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                            rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                      {
                        lhs :=
                          (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                ⋯).cast
                            ⋯,
                        rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                lhs :=
                  (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                            ⋯).cast
                        ⋯).cast
                    ⋯,
                rhs :=
                  ((blastShiftConcat
                              (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                              { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                        ⋯).cast
                    ⋯ }).aig,
        ref :=
          {
            gate :=
              (((RefVec.ite
                            (BVPred.mkUlt
                                (blastSub
                                    (blastShiftConcat
                                        (blastShiftConcat
                                            (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                            { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                        { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                                    {
                                      lhs :=
                                        ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                              ⋯).cast
                                          ⋯,
                                      rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                                {
                                  lhs :=
                                    (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                              ⋯).cast
                                          ⋯).cast
                                      ⋯,
                                  rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
                            {
                              discr :=
                                (BVPred.mkUlt
                                    (blastSub
                                        (blastShiftConcat
                                            (blastShiftConcat
                                                (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                            { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                                        {
                                          lhs :=
                                            ((blastShiftConcat aig
                                                        { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                                  ⋯).cast
                                              ⋯,
                                          rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                                    {
                                      lhs :=
                                        (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                                  ⋯).cast
                                              ⋯).cast
                                          ⋯,
                                      rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                              lhs :=
                                (((blastShiftConcat
                                                (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                                          ⋯).cast
                                      ⋯).cast
                                  ⋯,
                              rhs :=
                                ((blastShiftConcat
                                            (blastShiftConcat
                                                (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                                { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                            { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                                      ⋯).cast
                                  ⋯ }).vec.cast
                      ⋯).get
                  idx hidx).gate,
            hgate := ?m.6686 } }⟧ =
    (if rbv.shiftConcat (lhs.getLsbD (wn - 1)) < rhs then
            { wn := wn - 1, wr := wr + 1, q := qbv.shiftConcat false, r := rbv.shiftConcat (lhs.getLsbD (wn - 1)) }
          else
            { wn := wn - 1, wr := wr + 1, q := qbv.shiftConcat true,
              r := rbv.shiftConcat (lhs.getLsbD (wn - 1)) - rhs }).q.getLsbD
      idx

Tactic:
simp only [RefVec.get_cast, Ref.gate_cast]

Result:
α : Type
inst✝¹ : Hashable α
inst✝ : DecidableEq α
w : Nat
aig : AIG α
assign : α → Bool
lhs rhs : BitVec w
falseRef trueRef : aig.Ref
n d : aig.RefVec w
wn wr : Nat
q r : aig.RefVec w
qbv rbv : BitVec w
hleft : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := n.get idx hidx }⟧ = lhs.getLsbD idx
hright : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := d.get idx hidx }⟧ = rhs.getLsbD idx
hq : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := q.get idx hidx }⟧ = qbv.getLsbD idx
hr : ∀ (idx : Nat) (hidx : idx < w), ⟦assign, { aig := aig, ref := r.get idx hidx }⟧ = rbv.getLsbD idx
hfalse : ⟦assign, { aig := aig, ref := falseRef }⟧ = false
htrue : ⟦assign, { aig := aig, ref := trueRef }⟧ = true
idx : Nat
hidx : idx < w
⊢ ⟦assign,
      {
        aig :=
          (RefVec.ite
              (BVPred.mkUlt
                  (blastSub
                      (blastShiftConcat
                          (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                              { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                          { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                      { lhs := ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                        rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                  {
                    lhs :=
                      (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯).cast ⋯,
                    rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
              {
                discr :=
                  (BVPred.mkUlt
                      (blastSub
                          (blastShiftConcat
                              (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                              { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                          {
                            lhs :=
                              ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast ⋯,
                            rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                      {
                        lhs :=
                          (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                ⋯).cast
                            ⋯,
                        rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                lhs :=
                  (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                            ⋯).cast
                        ⋯).cast
                    ⋯,
                rhs :=
                  ((blastShiftConcat
                              (blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                  { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                              { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                        ⋯).cast
                    ⋯ }).aig,
        ref :=
          {
            gate :=
              ((RefVec.ite
                        (BVPred.mkUlt
                            (blastSub
                                (blastShiftConcat
                                    (blastShiftConcat
                                        (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                        { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                    { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                                {
                                  lhs :=
                                    ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                          ⋯).cast
                                      ⋯,
                                  rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                            {
                              lhs :=
                                (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast ⋯).cast
                                      ⋯).cast
                                  ⋯,
                              rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).aig
                        {
                          discr :=
                            (BVPred.mkUlt
                                (blastSub
                                    (blastShiftConcat
                                        (blastShiftConcat
                                            (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                            { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                        { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).aig
                                    {
                                      lhs :=
                                        ((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                              ⋯).cast
                                          ⋯,
                                      rhs := ((d.cast ⋯).cast ⋯).cast ⋯ }).aig
                                {
                                  lhs :=
                                    (((blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).vec.cast
                                              ⋯).cast
                                          ⋯).cast
                                      ⋯,
                                  rhs := (((d.cast ⋯).cast ⋯).cast ⋯).cast ⋯ }).ref,
                          lhs :=
                            (((blastShiftConcat (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                            { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).vec.cast
                                      ⋯).cast
                                  ⋯).cast
                              ⋯,
                          rhs :=
                            ((blastShiftConcat
                                        (blastShiftConcat
                                            (blastShiftConcat aig { lhs := r, bit := n.getD (wn - 1) falseRef }).aig
                                            { lhs := q.cast ⋯, bit := falseRef.cast ⋯ }).aig
                                        { lhs := (q.cast ⋯).cast ⋯, bit := (trueRef.cast ⋯).cast ⋯ }).vec.cast
                                  ⋯).cast
                              ⋯ }).vec.get
                  idx hidx).gate,
            hgate := ⋯ } }⟧ =
    (if rbv.shiftConcat (lhs.getLsbD (wn - 1)) < rhs then
            { wn := wn - 1, wr := wr + 1, q := qbv.shiftConcat false, r := rbv.shiftConcat (lhs.getLsbD (wn - 1)) }
          else
            { wn := wn - 1, wr := wr + 1, q := qbv.shiftConcat true,
              r := rbv.shiftConcat (lhs.getLsbD (wn - 1)) - rhs }).q.getLsbD
      idx