/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
 *  Main authors:
 *     Guido Tack <guido.tack@monash.edu>
 */

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <minizinc/flat_exp.hh>

#include <list>

namespace MiniZinc {

ASTString op_to_builtin(Expression* op_lhs, Expression* op_rhs, BinOpType bot) {
  std::string builtin;
  if (op_rhs->type().isint()) {
    switch (bot) {
      case BOT_PLUS:
        return constants().ids.int_.plus;
      case BOT_MINUS:
        return constants().ids.int_.minus;
      case BOT_MULT:
        return constants().ids.int_.times;
      case BOT_POW:
        return constants().ids.pow;
      case BOT_IDIV:
        return constants().ids.int_.div;
      case BOT_MOD:
        return constants().ids.int_.mod;
      case BOT_LE:
        return constants().ids.int_.lt;
      case BOT_LQ:
        return constants().ids.int_.le;
      case BOT_GR:
        return constants().ids.int_.gt;
      case BOT_GQ:
        return constants().ids.int_.ge;
      case BOT_EQ:
        return constants().ids.int_.eq;
      case BOT_NQ:
        return constants().ids.int_.ne;
      default:
        throw InternalError("not yet implemented");
    }
  } else if (op_rhs->type().isbool()) {
    if (bot == BOT_EQ || bot == BOT_EQUIV) {
      return constants().ids.bool_eq;
    }
    builtin = "bool_";
  } else if (op_rhs->type().isSet()) {
    builtin = "set_";
  } else if (op_rhs->type().isfloat()) {
    switch (bot) {
      case BOT_PLUS:
        return constants().ids.float_.plus;
      case BOT_MINUS:
        return constants().ids.float_.minus;
      case BOT_MULT:
        return constants().ids.float_.times;
      case BOT_POW:
        return constants().ids.pow;
      case BOT_DIV:
        return constants().ids.float_.div;
      case BOT_MOD:
        return constants().ids.float_.mod;
      case BOT_LE:
        return constants().ids.float_.lt;
      case BOT_LQ:
        return constants().ids.float_.le;
      case BOT_GR:
        return constants().ids.float_.gt;
      case BOT_GQ:
        return constants().ids.float_.ge;
      case BOT_EQ:
        return constants().ids.float_.eq;
      case BOT_NQ:
        return constants().ids.float_.ne;
      default:
        throw InternalError("not yet implemented");
    }
  } else if (op_rhs->type().isOpt() && (bot == BOT_EQUIV || bot == BOT_EQ)) {
    /// TODO: extend to all option type operators
    switch (op_lhs->type().bt()) {
      case Type::BT_BOOL:
        return constants().ids.bool_eq;
      case Type::BT_FLOAT:
        return constants().ids.float_.eq;
      case Type::BT_INT:
        if (op_lhs->type().st() == Type::ST_PLAIN) {
          return constants().ids.int_.eq;
        } else {
          return constants().ids.set_eq;
        }
      default:
        throw InternalError("not yet implemented");
    }

  } else {
    throw InternalError("Operator not yet implemented");
  }
  switch (bot) {
    case BOT_PLUS:
      return builtin + "plus";
    case BOT_MINUS:
      return builtin + "minus";
    case BOT_MULT:
      return builtin + "times";
    case BOT_DIV:
    case BOT_IDIV:
      return builtin + "div";
    case BOT_MOD:
      return builtin + "mod";
    case BOT_LE:
      return builtin + "lt";
    case BOT_LQ:
      return builtin + "le";
    case BOT_GR:
      return builtin + "gt";
    case BOT_GQ:
      return builtin + "ge";
    case BOT_EQ:
      return builtin + "eq";
    case BOT_NQ:
      return builtin + "ne";
    case BOT_IN:
      return constants().ids.set_in;
    case BOT_SUBSET:
      return builtin + "subset";
    case BOT_SUPERSET:
      return builtin + "superset";
    case BOT_UNION:
      return builtin + "union";
    case BOT_DIFF:
      return builtin + "diff";
    case BOT_SYMDIFF:
      return builtin + "symdiff";
    case BOT_INTERSECT:
      return builtin + "intersect";
    case BOT_PLUSPLUS:
    case BOT_DOTDOT:
      throw InternalError("not yet implemented");
    case BOT_EQUIV:
      return builtin + "eq";
    case BOT_IMPL:
      return builtin + "le";
    case BOT_RIMPL:
      return builtin + "ge";
    case BOT_OR:
      return builtin + "or";
    case BOT_AND:
      return builtin + "and";
    case BOT_XOR:
      return constants().ids.bool_xor;
    default:
      assert(false);
      return ASTString();
  }
}

ASTString op_to_id(BinOpType bot) {
  switch (bot) {
    case BOT_PLUS:
      return ASTString("'+'");
    case BOT_MINUS:
      return ASTString("'-'");
    case BOT_MULT:
      return ASTString("'*'");
    case BOT_DIV:
      return ASTString("'/'");
    case BOT_IDIV:
      return ASTString("'div'");
    case BOT_MOD:
      return ASTString("'mod'");
    case BOT_LE:
      return ASTString("'<'");
    case BOT_LQ:
      return ASTString("'<='");
    case BOT_GR:
      return ASTString("'>'");
    case BOT_GQ:
      return ASTString("'>='");
    case BOT_EQ:
      return ASTString("'='");
    case BOT_NQ:
      return ASTString("'!='");
    case BOT_IN:
      return ASTString("'in'");
    case BOT_SUBSET:
      return ASTString("'subset'");
    case BOT_SUPERSET:
      return ASTString("'superset'");
    case BOT_UNION:
      return ASTString("'union'");
    case BOT_DIFF:
      return ASTString("'diff'");
    case BOT_SYMDIFF:
      return ASTString("'symdiff'");
    case BOT_INTERSECT:
      return ASTString("'intersect'");
    case BOT_PLUSPLUS:
      return ASTString("'++'");
    case BOT_DOTDOT:
      return ASTString("'..'");
    case BOT_EQUIV:
      return ASTString("'<->'");
    case BOT_IMPL:
      return ASTString("'->'");
    case BOT_RIMPL:
      return ASTString("'<-'");
    case BOT_OR:
      return ASTString("'\\/'");
    case BOT_AND:
      return ASTString("'/\\'");
    case BOT_XOR:
      return ASTString("'xor'");
    default:
      assert(false);
      return ASTString("");
  }
}

bool is_reverse_map(BinOp* e) { return e->ann().contains(constants().ann.is_reverse_map); }

template <class Lit>
void collect_linexps(EnvI& env, typename LinearTraits<Lit>::Val in_c, Expression* exp,
                     std::vector<typename LinearTraits<Lit>::Val>& coeffs,
                     std::vector<KeepAlive>& vars, typename LinearTraits<Lit>::Val& constval) {
  typedef typename LinearTraits<Lit>::Val Val;
  struct StackItem {
    Expression* e;
    Val c;
    StackItem(Expression* e0, Val c0) : e(e0), c(c0) {}
  };
  std::vector<StackItem> stack;
  stack.push_back(StackItem(exp, in_c));
  while (!stack.empty()) {
    Expression* e = stack.back().e;
    Val c = stack.back().c;
    stack.pop_back();
    if (e == nullptr) {
      continue;
    }
    if (e->type().isPar()) {
      constval += c * LinearTraits<Lit>::eval(env, e);
    } else if (Lit* l = e->dynamicCast<Lit>()) {
      constval += c * l->v();
    } else if (auto* bo = e->dynamicCast<BinOp>()) {
      switch (bo->op()) {
        case BOT_PLUS:
          stack.push_back(StackItem(bo->lhs(), c));
          stack.push_back(StackItem(bo->rhs(), c));
          break;
        case BOT_MINUS:
          stack.push_back(StackItem(bo->lhs(), c));
          stack.push_back(StackItem(bo->rhs(), -c));
          break;
        case BOT_MULT:
          if (bo->lhs()->type().isPar()) {
            stack.push_back(StackItem(bo->rhs(), c * LinearTraits<Lit>::eval(env, bo->lhs())));
          } else if (bo->rhs()->type().isPar()) {
            stack.push_back(StackItem(bo->lhs(), c * LinearTraits<Lit>::eval(env, bo->rhs())));
          } else {
            coeffs.push_back(c);
            vars.emplace_back(e);
          }
          break;
        case BOT_DIV:
          if (bo->rhs()->isa<FloatLit>() && bo->rhs()->cast<FloatLit>()->v() == 1.0) {
            stack.push_back(StackItem(bo->lhs(), c));
          } else {
            coeffs.push_back(c);
            vars.emplace_back(e);
          }
          break;
        case BOT_IDIV:
          if (bo->rhs()->isa<IntLit>() && bo->rhs()->cast<IntLit>()->v() == 1) {
            stack.push_back(StackItem(bo->lhs(), c));
          } else {
            coeffs.push_back(c);
            vars.emplace_back(e);
          }
          break;
        default:
          coeffs.push_back(c);
          vars.emplace_back(e);
          break;
      }
      //      } else if (Call* call = e->dynamicCast<Call>()) {
      //        /// TODO! Handle sum, lin_exp (maybe not that important?)
    } else {
      coeffs.push_back(c);
      vars.emplace_back(e);
    }
  }
}

template <class Lit>
KeepAlive mklinexp(EnvI& env, typename LinearTraits<Lit>::Val c0,
                   typename LinearTraits<Lit>::Val c1, Expression* e0, Expression* e1) {
  typedef typename LinearTraits<Lit>::Val Val;
  GCLock lock;

  std::vector<Val> coeffs;
  std::vector<KeepAlive> vars;
  Val constval = 0;
  collect_linexps<Lit>(env, c0, e0, coeffs, vars, constval);
  collect_linexps<Lit>(env, c1, e1, coeffs, vars, constval);
  simplify_lin<Lit>(coeffs, vars, constval);
  KeepAlive ka;
  if (coeffs.empty()) {
    ka = LinearTraits<Lit>::newLit(constval);
  } else if (coeffs.size() == 1 && coeffs[0] == 1 && constval == 0) {
    ka = vars[0];
  } else {
    std::vector<Expression*> coeffs_e(coeffs.size());
    for (auto i = static_cast<unsigned int>(coeffs.size()); i--;) {
      if (!LinearTraits<Lit>::finite(coeffs[i])) {
        throw FlatteningError(
            env, e0->loc(),
            "unbounded coefficient in linear expression."
            " Make sure variables involved in non-linear/logical expressions have finite bounds"
            " in their definition or via constraints");
      }
      coeffs_e[i] = LinearTraits<Lit>::newLit(coeffs[i]);
    }
    std::vector<Expression*> vars_e(vars.size());
    for (auto i = static_cast<unsigned int>(vars.size()); i--;) {
      vars_e[i] = vars[i]();
    }

    std::vector<Expression*> args(3);
    args[0] = new ArrayLit(e0->loc(), coeffs_e);
    Type t = coeffs_e[0]->type();
    t.dim(1);
    args[0]->type(t);
    args[1] = new ArrayLit(e0->loc(), vars_e);
    Type tt = vars_e[0]->type();
    tt.dim(1);
    args[1]->type(tt);
    args[2] = LinearTraits<Lit>::newLit(constval);
    Call* c = new Call(e0->loc().introduce(), constants().ids.lin_exp, args);
    add_path_annotation(env, c);
    tt = args[1]->type();
    tt.dim(0);
    c->decl(env.model->matchFn(env, c, false));
    if (c->decl() == nullptr) {
      throw FlatteningError(env, c->loc(), "cannot find matching declaration");
    }
    c->type(c->decl()->rtype(env, args, false));
    ka = c;
  }
  assert(ka());
  return ka;
}

Call* aggregate_and_or_ops(EnvI& env, BinOp* bo, bool negateArgs, BinOpType bot) {
  assert(bot == BOT_AND || bot == BOT_OR);
  BinOpType negbot = (bot == BOT_AND ? BOT_OR : BOT_AND);
  typedef std::pair<Expression*, bool> arg_literal;
  typedef std::list<arg_literal> arg_literal_l;
  arg_literal_l bo_args({arg_literal(bo->lhs(), !negateArgs), arg_literal(bo->rhs(), !negateArgs)});
  std::vector<Expression*> output_pos;
  std::vector<Expression*> output_neg;
  auto i = bo_args.begin();
  while (i != bo_args.end()) {
    auto* bo_arg = i->first->dynamicCast<BinOp>();
    UnOp* uo_arg = i->first->dynamicCast<UnOp>();
    bool positive = i->second;
    if ((bo_arg != nullptr) && positive && bo_arg->op() == bot) {
      i->first = bo_arg->lhs();
      i++;
      bo_args.insert(i, arg_literal(bo_arg->rhs(), true));
      i--;
      i--;
    } else if ((bo_arg != nullptr) && !positive && bo_arg->op() == negbot) {
      i->first = bo_arg->lhs();
      i++;
      bo_args.insert(i, arg_literal(bo_arg->rhs(), false));
      i--;
      i--;
    } else if ((uo_arg != nullptr) && !positive && uo_arg->op() == UOT_NOT) {
      i->first = uo_arg->e();
      i->second = true;
    } else if (bot == BOT_OR && (uo_arg != nullptr) && positive && uo_arg->op() == UOT_NOT) {
      output_neg.push_back(uo_arg->e());
      i++;
    } else {
      if (positive) {
        output_pos.push_back(i->first);
      } else {
        output_neg.push_back(i->first);
      }
      i++;
    }
  }
  Call* c;
  std::vector<Expression*> c_args(1);
  if (bot == BOT_AND) {
    for (auto& i : output_neg) {
      UnOp* neg_arg = new UnOp(i->loc(), UOT_NOT, i);
      neg_arg->type(i->type());
      output_pos.push_back(neg_arg);
    }
    auto* al = new ArrayLit(bo->loc().introduce(), output_pos);
    Type al_t = bo->type();
    al_t.dim(1);
    al->type(al_t);
    env.annotateFromCallStack(al);
    c_args[0] = al;
    c = new Call(bo->loc().introduce(),
                 bot == BOT_AND ? constants().ids.forall : constants().ids.exists, c_args);
  } else {
    auto* al_pos = new ArrayLit(bo->loc().introduce(), output_pos);
    Type al_t = bo->type();
    al_t.dim(1);
    al_pos->type(al_t);
    env.annotateFromCallStack(al_pos);
    c_args[0] = al_pos;
    if (!output_neg.empty()) {
      auto* al_neg = new ArrayLit(bo->loc().introduce(), output_neg);
      al_neg->type(al_t);
      env.annotateFromCallStack(al_neg);
      c_args.push_back(al_neg);
    }
    c = new Call(bo->loc().introduce(),
                 output_neg.empty() ? constants().ids.exists : constants().ids.clause, c_args);
  }
  c->decl(env.model->matchFn(env, c, false));
  assert(c->decl());
  Type t = c->decl()->rtype(env, c_args, false);
  t.cv(bo->type().cv());
  c->type(t);
  return c;
}

/// Return a lin_exp or id if \a e is a lin_exp or id
template <class Lit>
Expression* get_linexp(Expression* e) {
  for (;;) {
    if (e && e->eid() == Expression::E_ID && e != constants().absent) {
      if (e->cast<Id>()->decl()->e()) {
        e = e->cast<Id>()->decl()->e();
      } else {
        break;
      }
    } else {
      break;
    }
  }
  if (e && (e->isa<Id>() || e->isa<Lit>() ||
            (e->isa<Call>() && e->cast<Call>()->id() == constants().ids.lin_exp))) {
    return e;
  }
  return nullptr;
}

template <class Lit>
void flatten_linexp_binop(EnvI& env, const Ctx& ctx, VarDecl* r, VarDecl* b, EE& ret,
                          Expression* le0, Expression* le1, BinOpType& bot, bool doubleNeg,
                          std::vector<EE>& ees, std::vector<KeepAlive>& args, ASTString& callid) {
  typedef typename LinearTraits<Lit>::Val Val;
  std::vector<Val> coeffv;
  std::vector<KeepAlive> alv;
  Val d = 0;
  Expression* le[2] = {le0, le1};

  // Assign linear expression directly if one side is an Id.
  Id* assignTo = nullptr;
  if (bot == BOT_EQ && ctx.b == C_ROOT) {
    if (le0->isa<Id>()) {
      assignTo = le0->cast<Id>();
    } else if (le1->isa<Id>()) {
      assignTo = le1->cast<Id>();
    }
  }

  for (unsigned int i = 0; i < 2; i++) {
    Val sign = (i == 0 ? 1 : -1);
    if (Lit* l = le[i]->dynamicCast<Lit>()) {
      try {
        d += sign * l->v();
      } catch (ArithmeticError& e) {
        throw EvalError(env, l->loc(), e.msg());
      }
    } else if (le[i]->isa<Id>()) {
      coeffv.push_back(sign);
      alv.emplace_back(le[i]);
    } else if (Call* sc = le[i]->dynamicCast<Call>()) {
      GCLock lock;
      ArrayLit* sc_coeff = eval_array_lit(env, sc->arg(0));
      ArrayLit* sc_al = eval_array_lit(env, sc->arg(1));
      try {
        d += sign * LinearTraits<Lit>::eval(env, sc->arg(2));
        for (unsigned int j = 0; j < sc_coeff->size(); j++) {
          coeffv.push_back(sign * LinearTraits<Lit>::eval(env, (*sc_coeff)[j]));
          alv.emplace_back((*sc_al)[j]);
        }
      } catch (ArithmeticError& e) {
        throw EvalError(env, sc->loc(), e.msg());
      }

    } else {
      throw EvalError(env, le[i]->loc(),
                      "Internal error, unexpected expression inside linear expression");
    }
  }
  simplify_lin<Lit>(coeffv, alv, d);
  if (coeffv.empty()) {
    bool result;
    switch (bot) {
      case BOT_LE:
        result = (0 < -d);
        break;
      case BOT_LQ:
        result = (0 <= -d);
        break;
      case BOT_GR:
        result = (0 > -d);
        break;
      case BOT_GQ:
        result = (0 >= -d);
        break;
      case BOT_EQ:
        result = (0 == -d);
        break;
      case BOT_NQ:
        result = (0 != -d);
        break;
      default:
        assert(false);
        break;
    }
    if (doubleNeg) {
      result = !result;
    }
    ees[2].b = constants().boollit(result);
    ret.r = conj(env, r, ctx, ees);
    return;
  }
  if (coeffv.size() == 1 && std::abs(coeffv[0]) == 1) {
    if (coeffv[0] == -1) {
      switch (bot) {
        case BOT_LE:
          bot = BOT_GR;
          break;
        case BOT_LQ:
          bot = BOT_GQ;
          break;
        case BOT_GR:
          bot = BOT_LE;
          break;
        case BOT_GQ:
          bot = BOT_LQ;
          break;
        default:
          break;
      }
    } else {
      d = -d;
    }
    typename LinearTraits<Lit>::Bounds ib = LinearTraits<Lit>::computeBounds(env, alv[0]());
    if (ib.valid) {
      bool failed = false;
      bool subsumed = false;
      switch (bot) {
        case BOT_LE:
          subsumed = ib.u < d;
          failed = ib.l >= d;
          break;
        case BOT_LQ:
          subsumed = ib.u <= d;
          failed = ib.l > d;
          break;
        case BOT_GR:
          subsumed = ib.l > d;
          failed = ib.u <= d;
          break;
        case BOT_GQ:
          subsumed = ib.l >= d;
          failed = ib.u < d;
          break;
        case BOT_EQ:
          subsumed = ib.l == d && ib.u == d;
          failed = ib.u < d || ib.l > d;
          break;
        case BOT_NQ:
          subsumed = ib.u < d || ib.l > d;
          failed = ib.l == d && ib.u == d;
          break;
        default:
          break;
      }
      if (doubleNeg) {
        std::swap(subsumed, failed);
      }
      if (subsumed) {
        ees[2].b = constants().literalTrue;
        ret.r = conj(env, r, ctx, ees);
        return;
      }
      if (failed) {
        ees[2].b = constants().literalFalse;
        ret.r = conj(env, r, ctx, ees);
        return;
      }
    }

    if (ctx.b == C_ROOT && alv[0]()->isa<Id>() && bot == BOT_EQ) {
      GCLock lock;
      VarDecl* vd = alv[0]()->cast<Id>()->decl();
      if (vd->ti()->domain()) {
        typename LinearTraits<Lit>::Domain domain =
            LinearTraits<Lit>::evalDomain(env, vd->ti()->domain());
        if (LinearTraits<Lit>::domainContains(domain, d)) {
          if (!LinearTraits<Lit>::domainEquals(domain, d)) {
            set_computed_domain(env, vd, LinearTraits<Lit>::newDomain(d), false);
          }
          ret.r = bind(env, ctx, r, constants().literalTrue);
        } else {
          ret.r = bind(env, ctx, r, constants().literalFalse);
        }
      } else {
        set_computed_domain(env, vd, LinearTraits<Lit>::newDomain(d), false);
        ret.r = bind(env, ctx, r, constants().literalTrue);
      }
    } else {
      GCLock lock;
      Expression* e0;
      Expression* e1;
      BinOpType old_bot = bot;
      Val old_d = d;
      switch (bot) {
        case BOT_LE:
          e0 = alv[0]();
          if (e0->type().isint()) {
            d--;
            bot = BOT_LQ;
          }
          e1 = LinearTraits<Lit>::newLit(d);
          break;
        case BOT_GR:
          e1 = alv[0]();
          if (e1->type().isint()) {
            d++;
            bot = BOT_LQ;
          } else {
            bot = BOT_LE;
          }
          e0 = LinearTraits<Lit>::newLit(d);
          break;
        case BOT_GQ:
          e0 = LinearTraits<Lit>::newLit(d);
          e1 = alv[0]();
          bot = BOT_LQ;
          break;
        default:
          e0 = alv[0]();
          e1 = LinearTraits<Lit>::newLit(d);
      }
      if (ctx.b == C_ROOT && alv[0]()->isa<Id>() && !env.hasReverseMapper(alv[0]()->cast<Id>()) &&
          alv[0]()->cast<Id>()->decl()->ti()->domain()) {
        VarDecl* vd = alv[0]()->cast<Id>()->decl();
        typename LinearTraits<Lit>::Domain domain =
            LinearTraits<Lit>::evalDomain(env, vd->ti()->domain());
        typename LinearTraits<Lit>::Domain ndomain =
            LinearTraits<Lit>::limitDomain(old_bot, domain, old_d);
        if (domain && ndomain) {
          if (LinearTraits<Lit>::domainEmpty(ndomain)) {
            ret.r = bind(env, ctx, r, constants().literalFalse);
            return;
          }
          if (!LinearTraits<Lit>::domainEquals(domain, ndomain)) {
            ret.r = bind(env, ctx, r, constants().literalTrue);
            set_computed_domain(env, vd, LinearTraits<Lit>::newDomain(ndomain), false);

            if (r == constants().varTrue) {
              auto* bo = new BinOp(Location().introduce(), e0, bot, e1);
              bo->type(Type::varbool());
              std::vector<Expression*> boargs(2);
              boargs[0] = e0;
              boargs[1] = e1;
              Call* c = new Call(Location(), op_to_builtin(e0, e1, bot), boargs);
              c->type(Type::varbool());
              c->decl(env.model->matchFn(env, c, false));
              auto it = env.cseMapFind(c);
              if (it != env.cseMapEnd()) {
                if (Id* ident = it->second.r()->template dynamicCast<Id>()) {
                  bind(env, Ctx(), ident->decl(), constants().literalTrue);
                  it->second.r = constants().literalTrue;
                }
                if (Id* ident = it->second.b()->template dynamicCast<Id>()) {
                  bind(env, Ctx(), ident->decl(), constants().literalTrue);
                  it->second.b = constants().literalTrue;
                }
              }
            }
          }
          return;
        }
      }
      args.emplace_back(e0);
      args.emplace_back(e1);
    }
  } else if (bot == BOT_EQ && coeffv.size() == 2 && coeffv[0] == -coeffv[1] && d == 0) {
    Id* id0 = alv[0]()->cast<Id>();
    Id* id1 = alv[1]()->cast<Id>();
    if (ctx.b == C_ROOT && r == constants().varTrue &&
        (id0->decl()->e() == nullptr || id1->decl()->e() == nullptr)) {
      if (id0->decl()->e()) {
        (void)bind(env, ctx, id1->decl(), id0);
      } else {
        (void)bind(env, ctx, id0->decl(), id1);
      }
    } else {
      callid = LinearTraits<Lit>::id_eq();
      args.emplace_back(alv[0]());
      args.emplace_back(alv[1]());
    }
  } else {
    GCLock lock;
    if (assignTo != nullptr) {
      Val resultCoeff = 0;
      typename LinearTraits<Lit>::Bounds bounds(d, d, true);
      for (auto i = static_cast<unsigned int>(coeffv.size()); i--;) {
        if (alv[i]() == assignTo) {
          resultCoeff = coeffv[i];
          continue;
        }
        typename LinearTraits<Lit>::Bounds bound = LinearTraits<Lit>::computeBounds(env, alv[i]());

        if (bound.valid && LinearTraits<Lit>::finite(bound)) {
          if (coeffv[i] > 0) {
            bounds.l += coeffv[i] * bound.l;
            bounds.u += coeffv[i] * bound.u;
          } else {
            bounds.l += coeffv[i] * bound.u;
            bounds.u += coeffv[i] * bound.l;
          }
        } else {
          bounds.valid = false;
          break;
        }
      }
      if (bounds.valid && resultCoeff != 0) {
        if (resultCoeff < 0) {
          bounds.l = LinearTraits<Lit>::floorDiv(bounds.l, -resultCoeff);
          bounds.u = LinearTraits<Lit>::ceilDiv(bounds.u, -resultCoeff);
        } else {
          Val bl = bounds.l;
          bounds.l = LinearTraits<Lit>::ceilDiv(bounds.u, -resultCoeff);
          bounds.u = LinearTraits<Lit>::floorDiv(bl, -resultCoeff);
        }
        VarDecl* vd = assignTo->decl();
        if (vd->ti()->domain()) {
          typename LinearTraits<Lit>::Domain domain =
              LinearTraits<Lit>::evalDomain(env, vd->ti()->domain());
          if (LinearTraits<Lit>::domainIntersects(domain, bounds.l, bounds.u)) {
            typename LinearTraits<Lit>::Domain new_domain =
                LinearTraits<Lit>::intersectDomain(domain, bounds.l, bounds.u);
            if (!LinearTraits<Lit>::domainEquals(domain, new_domain)) {
              set_computed_domain(env, vd, LinearTraits<Lit>::newDomain(new_domain), false);
            }
          } else {
            ret.r = bind(env, ctx, r, constants().literalFalse);
          }
        } else {
          set_computed_domain(env, vd, LinearTraits<Lit>::newDomain(bounds.l, bounds.u), true);
        }
      }
    }

    int coeff_sign;
    LinearTraits<Lit>::constructLinBuiltin(bot, callid, coeff_sign, d);
    std::vector<Expression*> coeff_ev(coeffv.size());
    for (auto i = static_cast<unsigned int>(coeff_ev.size()); i--;) {
      coeff_ev[i] = LinearTraits<Lit>::newLit(coeff_sign * coeffv[i]);
    }
    auto* ncoeff = new ArrayLit(Location().introduce(), coeff_ev);
    Type t = coeff_ev[0]->type();
    t.dim(1);
    ncoeff->type(t);
    args.emplace_back(ncoeff);
    std::vector<Expression*> alv_e(alv.size());
    Type tt = alv[0]()->type();
    tt.dim(1);
    for (auto i = static_cast<unsigned int>(alv.size()); i--;) {
      if (alv[i]()->type().isvar()) {
        tt.ti(Type::TI_VAR);
      }
      alv_e[i] = alv[i]();
    }
    auto* nal = new ArrayLit(Location().introduce(), alv_e);
    nal->type(tt);
    args.emplace_back(nal);
    Lit* il = LinearTraits<Lit>::newLit(-d);
    args.push_back(il);
  }
}

EE flatten_binop(EnvI& env, const Ctx& input_ctx, Expression* e, VarDecl* r, VarDecl* b) {
  Ctx ctx = input_ctx;
  CallStackItem _csi(env, e);
  EE ret;
  auto* bo = e->cast<BinOp>();
  if (is_reverse_map(bo)) {
    CallArgItem cai(env);
    Id* id = bo->lhs()->dynamicCast<Id>();
    if (id == nullptr) {
      throw EvalError(env, bo->lhs()->loc(), "Reverse mappers are only defined for identifiers");
    }
    if (bo->op() != BOT_EQ && bo->op() != BOT_EQUIV) {
      throw EvalError(env, bo->loc(), "Reverse mappers have to use `=` as the operator");
    }
    Call* c = bo->rhs()->dynamicCast<Call>();
    if (c == nullptr) {
      throw EvalError(env, bo->rhs()->loc(), "Reverse mappers require call on right hand side");
    }

    std::vector<Expression*> args(c->argCount());
    for (unsigned int i = 0; i < c->argCount(); i++) {
      Id* idi = c->arg(i)->dynamicCast<Id>();
      if (idi == nullptr) {
        throw EvalError(env, c->arg(i)->loc(),
                        "Reverse mapper calls require identifiers as arguments");
      }
      EE ee = flat_exp(env, Ctx(), idi, nullptr, constants().varTrue);
      args[i] = ee.r();
    }

    EE ee = flat_exp(env, Ctx(), id, nullptr, constants().varTrue);

    GCLock lock;
    Call* revMap = new Call(Location().introduce(), c->id(), args);

    args.push_back(ee.r());
    Call* keepAlive = new Call(Location().introduce(), constants().varRedef->id(), args);
    keepAlive->type(Type::varbool());
    keepAlive->decl(constants().varRedef);
    ret = flat_exp(env, Ctx(), keepAlive, constants().varTrue, constants().varTrue);

    if (ee.r()->isa<Id>()) {
      env.reverseMappers.insert(ee.r()->cast<Id>(), revMap);
    }
    return ret;
  }
  if ((bo->op() == BOT_EQ || bo->op() == BOT_EQUIV) &&
      (bo->lhs() == constants().absent || bo->rhs() == constants().absent)) {
    GCLock lock;
    std::vector<Expression*> args(1);
    args[0] = bo->lhs() == constants().absent ? bo->rhs() : bo->lhs();
    if (args[0] != constants().absent) {
      Call* cr = new Call(bo->loc().introduce(), "absent", args);
      cr->decl(env.model->matchFn(env, cr, false));
      cr->type(cr->decl()->rtype(env, args, false));
      ret = flat_exp(env, ctx, cr, r, b);
    } else {
      ret.b = bind(env, Ctx(), b, constants().literalTrue);
      ret.r = bind(env, ctx, r, constants().literalTrue);
    }
    return ret;
  }
  Ctx ctx0 = ctx;
  ctx0.neg = false;
  Ctx ctx1 = ctx;
  ctx1.neg = false;
  BinOpType bot = bo->op();
  if (bo->lhs()->type().isbool()) {
    switch (bot) {
      case BOT_EQ:
        bot = BOT_EQUIV;
        break;
      case BOT_NQ:
        bot = BOT_XOR;
        break;
      case BOT_LQ:
        bot = BOT_IMPL;
        break;
      case BOT_GQ:
        bot = BOT_RIMPL;
        break;
      default:
        break;
    }
  }
  bool negArgs = false;
  bool doubleNeg = false;
  if (ctx.neg) {
    switch (bot) {
      case BOT_AND:
        ctx.b = -ctx.b;
        ctx.neg = false;
        negArgs = true;
        bot = BOT_OR;
        break;
      case BOT_OR:
        ctx.b = -ctx.b;
        ctx.neg = false;
        negArgs = true;
        bot = BOT_AND;
        break;
      default:
        break;
    }
  }
  Expression* boe0 = bo->lhs();
  Expression* boe1 = bo->rhs();
  bool isBuiltin = bo->decl() == nullptr || bo->decl()->e() == nullptr;
  switch (bot) {
    case BOT_AND:
      if (isBuiltin) {
        if (r == constants().varTrue) {
          Ctx nctx;
          nctx.neg = negArgs;
          nctx.b = negArgs ? C_NEG : C_ROOT;
          std::vector<Expression*> todo;
          todo.push_back(boe1);
          todo.push_back(boe0);
          while (!todo.empty()) {
            Expression* e_todo = todo.back();
            todo.pop_back();
            auto* e_bo = e_todo->dynamicCast<BinOp>();
            if ((e_bo != nullptr) && e_bo->op() == (negArgs ? BOT_OR : BOT_AND)) {
              todo.push_back(e_bo->rhs());
              todo.push_back(e_bo->lhs());
            } else {
              (void)flat_exp(env, nctx, e_todo, constants().varTrue, constants().varTrue);
            }
          }
          ret.r = bind(env, ctx, r, constants().literalTrue);
          break;
        }
        GC::lock();
        Call* c = aggregate_and_or_ops(env, bo, negArgs, bot);
        KeepAlive ka(c);
        GC::unlock();
        ret = flat_exp(env, ctx, c, r, b);
        if (Id* id = ret.r()->dynamicCast<Id>()) {
          add_ctx_ann(id->decl(), ctx.b);
        }
        break;
      }
    case BOT_OR:
      if (isBuiltin) {
        GC::lock();
        Call* c = aggregate_and_or_ops(env, bo, negArgs, bot);
        KeepAlive ka(c);
        GC::unlock();
        ret = flat_exp(env, ctx, c, r, b);
        if (Id* id = ret.r()->dynamicCast<Id>()) {
          add_ctx_ann(id->decl(), ctx.b);
        }
        break;
      }
    case BOT_PLUS:
      if (isBuiltin) {
        KeepAlive ka;
        if (boe0->type().isint()) {
          ka = mklinexp<IntLit>(env, 1, 1, boe0, boe1);
        } else {
          ka = mklinexp<FloatLit>(env, 1.0, 1.0, boe0, boe1);
        }
        ret = flat_exp(env, ctx, ka(), r, b);
        break;
      }
    case BOT_MINUS:
      if (isBuiltin) {
        KeepAlive ka;
        if (boe0->type().isint()) {
          ka = mklinexp<IntLit>(env, 1, -1, boe0, boe1);
        } else {
          ka = mklinexp<FloatLit>(env, 1.0, -1.0, boe0, boe1);
        }
        ret = flat_exp(env, ctx, ka(), r, b);
        break;
      }
    case BOT_MULT:
    case BOT_IDIV:
    case BOT_MOD:
    case BOT_POW:
    case BOT_DIV:
    case BOT_UNION:
    case BOT_DIFF:
    case BOT_SYMDIFF:
    case BOT_INTERSECT:
    case BOT_DOTDOT: {
      assert(!ctx0.neg);
      assert(!ctx1.neg);
      EE e0 = flat_exp(env, ctx0, boe0, nullptr, b);
      EE e1 = flat_exp(env, ctx1, boe1, nullptr, b);

      if (e0.r()->type().isPar() && e1.r()->type().isPar()) {
        GCLock lock;
        auto* parbo = new BinOp(bo->loc(), e0.r(), bo->op(), e1.r());
        std::vector<Expression*> args(2);
        args[0] = e0.r();
        args[1] = e1.r();
        FunctionI* fi = env.model->matchFn(env, bo->opToString(), args, false);
        parbo->decl(fi);
        Type tt = fi->rtype(env, {e0.r()->type(), e1.r()->type()}, false);
        assert(tt.isPar());
        parbo->type(tt);
        try {
          Expression* res = eval_par(env, parbo);
          assert(!res->type().isunknown());
          ret.r = bind(env, ctx, r, res);
          std::vector<EE> ees(2);
          ees[0].b = e0.b;
          ees[1].b = e1.b;
          ret.b = conj(env, b, Ctx(), ees);
        } catch (ResultUndefinedError&) {
          ret.r = create_dummy_value(env, e->type());
          ret.b = bind(env, Ctx(), b, constants().literalFalse);
        }
        break;
      }

      if (isBuiltin && bot == BOT_MULT) {
        Expression* e0r = e0.r();
        Expression* e1r = e1.r();
        if (e0r->type().isPar()) {
          std::swap(e0r, e1r);
        }
        if (e1r->type().isPar() && e1r->type().isint()) {
          IntVal coeff = eval_int(env, e1r);
          KeepAlive ka = mklinexp<IntLit>(env, coeff, 0, e0r, nullptr);
          ret = flat_exp(env, ctx, ka(), r, b);
          break;
        }
        if (e1r->type().isPar() && e1r->type().isfloat()) {
          FloatVal coeff = eval_float(env, e1r);
          KeepAlive ka = mklinexp<FloatLit>(env, coeff, 0.0, e0r, nullptr);
          ret = flat_exp(env, ctx, ka(), r, b);
          break;
        }
      } else if (isBuiltin && (bot == BOT_DIV || bot == BOT_IDIV)) {
        Expression* e0r = e0.r();
        Expression* e1r = e1.r();
        if (e1r->type().isPar() && e1r->type().isint()) {
          IntVal coeff = eval_int(env, e1r);
          if (coeff == 1) {
            ret = flat_exp(env, ctx, e0r, r, b);
            break;
          }
        } else if (e1r->type().isPar() && e1r->type().isfloat()) {
          FloatVal coeff = eval_float(env, e1r);
          if (coeff == 1.0) {
            ret = flat_exp(env, ctx, e0r, r, b);
            break;
          }
          KeepAlive ka = mklinexp<FloatLit>(env, 1.0 / coeff, 0.0, e0r, nullptr);
          ret = flat_exp(env, ctx, ka(), r, b);
          break;
        }
      }

      GC::lock();
      std::vector<Expression*> args(2);
      args[0] = e0.r();
      args[1] = e1.r();
      Call* cc;
      if (!isBuiltin) {
        cc = new Call(bo->loc().introduce(), bo->opToString(), args);
      } else {
        cc = new Call(bo->loc().introduce(), op_to_builtin(args[0], args[1], bot), args);
      }
      cc->type(bo->type());
      EnvI::CSEMap::iterator cit;
      if ((cit = env.cseMapFind(cc)) != env.cseMapEnd()) {
        ret.b = bind(env, Ctx(), b, env.ignorePartial ? constants().literalTrue : cit->second.b());
        ret.r = bind(env, ctx, r, cit->second.r());
      } else {
        if (FunctionI* fi = env.model->matchFn(env, cc->id(), args, false)) {
          assert(cc->type() == fi->rtype(env, args, false));
          cc->decl(fi);
          cc->type(cc->decl()->rtype(env, args, false));
          KeepAlive ka(cc);
          GC::unlock();
          EE ee = flat_exp(env, ctx, cc, r, nullptr);
          GC::lock();
          ret.r = ee.r;
          std::vector<EE> ees(3);
          ees[0].b = e0.b;
          ees[1].b = e1.b;
          ees[2].b = ee.b;
          ret.b = conj(env, b, Ctx(), ees);
        } else {
          add_path_annotation(env, cc);
          ret.r = bind(env, ctx, r, cc);
          std::vector<EE> ees(2);
          ees[0].b = e0.b;
          ees[1].b = e1.b;
          ret.b = conj(env, b, Ctx(), ees);
          if (!ctx.neg) {
            env.cseMapInsert(cc, ret);
          }
        }
      }
    }
      GC::unlock();
      break;
    case BOT_RIMPL: {
      std::swap(boe0, boe1);
    }
      // fall through
    case BOT_IMPL: {
      if (ctx.b == C_ROOT && r == constants().varTrue && boe0->type().isPar()) {
        bool bval;
        {
          GCLock lock;
          bval = eval_bool(env, boe0);
        }
        if (bval) {
          Ctx nctx = ctx;
          nctx.neg = negArgs;
          nctx.b = negArgs ? C_NEG : C_ROOT;
          ret = flat_exp(env, nctx, boe1, constants().varTrue, constants().varTrue);
        } else {
          Ctx nctx = ctx;
          nctx.neg = negArgs;
          nctx.b = negArgs ? C_NEG : C_ROOT;
          ret = flat_exp(env, nctx, constants().literalTrue, constants().varTrue,
                         constants().varTrue);
        }
        break;
      }
      if (ctx.b == C_ROOT && r == constants().varTrue && boe1->type().isPar()) {
        bool bval;
        {
          GCLock lock;
          bval = eval_bool(env, boe1);
        }
        if (bval) {
          Ctx nctx = ctx;
          nctx.neg = negArgs;
          nctx.b = negArgs ? C_NEG : C_ROOT;
          ret = flat_exp(env, nctx, constants().literalTrue, constants().varTrue,
                         constants().varTrue);
          break;
        }
        Ctx nctx = ctx;
        nctx.neg = !negArgs;
        nctx.b = !negArgs ? C_NEG : C_ROOT;
        ret = flat_exp(env, nctx, boe0, constants().varTrue, constants().varTrue);
        break;
      }
      GC::lock();
      std::vector<Expression*> args;
      ASTString id;
      if (ctx.neg) {
        std::vector<Expression*> bo_args(2);
        bo_args[0] = boe0;
        bo_args[1] = new UnOp(bo->loc(), UOT_NOT, boe1);
        bo_args[1]->type(boe1->type());
        id = constants().ids.forall;
        args.push_back(new ArrayLit(bo->loc(), bo_args));
        args[0]->type(Type::varbool(1));
      } else {
        std::vector<Expression*> clause_pos(1);
        clause_pos[0] = boe1;
        std::vector<Expression*> clause_neg(1);
        clause_neg[0] = boe0;
        args.push_back(new ArrayLit(boe1->loc().introduce(), clause_pos));
        Type t0 = boe1->type();
        t0.dim(1);
        args[0]->type(t0);
        args.push_back(new ArrayLit(boe0->loc().introduce(), clause_neg));
        Type t1 = boe0->type();
        t1.dim(1);
        args[1]->type(t1);
        id = constants().ids.clause;
      }
      ctx.neg = false;
      Call* c = new Call(bo->loc().introduce(), id, args);
      c->decl(env.model->matchFn(env, c, false));
      if (c->decl() == nullptr) {
        throw FlatteningError(env, c->loc(), "cannot find matching declaration");
      }
      c->type(c->decl()->rtype(env, args, false));
      KeepAlive ka(c);
      GC::unlock();
      ret = flat_exp(env, ctx, c, r, b);
      if (Id* id = ret.r()->dynamicCast<Id>()) {
        add_ctx_ann(id->decl(), ctx.b);
      }
    } break;
    case BOT_EQUIV:
      if (ctx.neg) {
        ctx.neg = false;
        ctx.b = -ctx.b;
        bot = BOT_XOR;
        ctx0.b = ctx1.b = C_MIX;
        goto flatten_bool_op;
      }
      if (!boe1->type().isOpt() && istrue(env, boe0)) {
        return flat_exp(env, ctx, boe1, r, b);
      }
      if (!boe0->type().isOpt() && istrue(env, boe1)) {
        return flat_exp(env, ctx, boe0, r, b);
      }
      if (!boe0->type().isOpt() && !boe1->type().isOpt() && (r != nullptr) &&
          r == constants().varTrue) {
        if (boe1->type().isPar() || boe1->isa<Id>()) {
          std::swap(boe0, boe1);
        }
        if (istrue(env, boe0)) {
          return flat_exp(env, ctx1, boe1, r, b);
        }
        if (isfalse(env, boe0)) {
          ctx1.neg = true;
          ctx1.b = -ctx1.b;
          return flat_exp(env, ctx1, boe1, r, b);
        }
        ctx0.b = C_MIX;
        EE e0 = flat_exp(env, ctx0, boe0, nullptr, nullptr);
        if (istrue(env, e0.r())) {
          return flat_exp(env, ctx1, boe1, r, b);
        }
        if (isfalse(env, e0.r())) {
          ctx1.neg = true;
          ctx1.b = -ctx1.b;
          return flat_exp(env, ctx1, boe1, r, b);
        }
        Id* id = e0.r()->cast<Id>();
        ctx1.b = C_MIX;
        (void)flat_exp(env, ctx1, boe1, id->decl(), constants().varTrue);
        add_ctx_ann(id->decl(), ctx1.b);
        ret.b = bind(env, Ctx(), b, constants().literalTrue);
        ret.r = bind(env, Ctx(), r, constants().literalTrue);
        break;
      }
      ctx0.b = ctx1.b = C_MIX;
      goto flatten_bool_op;
    case BOT_XOR:
      if (ctx.neg) {
        ctx.neg = false;
        ctx.b = -ctx.b;
        bot = BOT_EQUIV;
      }
      ctx0.b = ctx1.b = C_MIX;
      goto flatten_bool_op;
    case BOT_LE:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_GQ;
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = +ctx0.b;
          ctx1.b = -ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = +ctx0.b;
          ctx1.i = -ctx1.b;
        }
      } else {
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = -ctx0.b;
          ctx1.b = +ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = -ctx0.b;
          ctx1.i = +ctx1.b;
        }
      }
      goto flatten_bool_op;
    case BOT_LQ:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_GR;
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = +ctx0.b;
          ctx1.b = -ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = +ctx0.b;
          ctx1.i = -ctx1.b;
        }
      } else {
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = -ctx0.b;
          ctx1.b = +ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = -ctx0.b;
          ctx1.i = +ctx1.b;
        }
      }
      goto flatten_bool_op;
    case BOT_GR:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_LQ;
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = -ctx0.b;
          ctx1.b = +ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = -ctx0.b;
          ctx1.i = +ctx1.b;
        }
      } else {
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = +ctx0.b;
          ctx1.b = -ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = +ctx0.b;
          ctx1.i = -ctx1.b;
        }
      }
      goto flatten_bool_op;
    case BOT_GQ:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_LE;
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = -ctx0.b;
          ctx1.b = +ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = -ctx0.b;
          ctx1.i = +ctx1.b;
        }
      } else {
        if (boe0->type().bt() == Type::BT_BOOL) {
          ctx0.b = +ctx0.b;
          ctx1.b = -ctx1.b;
        } else if (boe0->type().bt() == Type::BT_INT) {
          ctx0.i = +ctx0.b;
          ctx1.i = -ctx1.b;
        }
      }
      goto flatten_bool_op;
    case BOT_EQ:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_NQ;
      }
      if (boe0->type().bt() == Type::BT_BOOL) {
        ctx0.b = ctx1.b = C_MIX;
      } else if (boe0->type().bt() == Type::BT_INT) {
        ctx0.i = ctx1.i = C_MIX;
      }
      goto flatten_bool_op;
    case BOT_NQ:
      if (ctx.neg) {
        doubleNeg = true;
        bot = BOT_EQ;
      }
      if (boe0->type().bt() == Type::BT_BOOL) {
        ctx0.b = ctx1.b = C_MIX;
      } else if (boe0->type().bt() == Type::BT_INT) {
        ctx0.i = ctx1.i = C_MIX;
      }
      goto flatten_bool_op;
    case BOT_IN:
    case BOT_SUBSET:
    case BOT_SUPERSET:
      ctx0.i = ctx1.i = C_MIX;
    flatten_bool_op : {
      bool inRootCtx = (ctx0.b == ctx1.b && ctx0.b == C_ROOT && b == constants().varTrue);
      EE e0 = flat_exp(env, ctx0, boe0, nullptr, inRootCtx ? b : nullptr);
      EE e1 = flat_exp(env, ctx1, boe1, nullptr, inRootCtx ? b : nullptr);

      ret.b = bind(env, Ctx(), b, constants().literalTrue);

      std::vector<EE> ees(3);
      ees[0].b = e0.b;
      ees[1].b = e1.b;

      if (isfalse(env, e0.b()) || isfalse(env, e1.b())) {
        ees.resize(2);
        ret.r = conj(env, r, ctx, ees);
        break;
      }

      if (e0.r()->type().isPar() && e1.r()->type().isPar()) {
        GCLock lock;
        auto* bo_par = new BinOp(e->loc(), e0.r(), bot, e1.r());
        std::vector<Expression*> args({e0.r(), e1.r()});
        bo_par->decl(env.model->matchFn(env, bo_par->opToString(), args, false));
        if (bo_par->decl() == nullptr) {
          throw FlatteningError(env, bo_par->loc(), "cannot find matching declaration");
        }
        bo_par->type(Type::parbool());
        bool bo_val = eval_bool(env, bo_par);
        if (doubleNeg) {
          bo_val = !bo_val;
        }
        ees[2].b = constants().boollit(bo_val);
        ret.r = conj(env, r, ctx, ees);
        break;
      }

      if (e0.r()->type().bt() == Type::BT_INT && e1.r()->type().isPar() && e0.r()->isa<Id>() &&
          (bot == BOT_IN || bot == BOT_SUBSET)) {
        VarDecl* vd = e0.r()->cast<Id>()->decl();
        Id* ident = vd->id();
        if (ctx.b == C_ROOT && r == constants().varTrue) {
          if (vd->ti()->domain() == nullptr) {
            vd->ti()->domain(e1.r());
          } else {
            GCLock lock;
            IntSetVal* newdom = eval_intset(env, e1.r());
            while (ident != nullptr) {
              bool changeDom = false;
              if (ident->decl()->ti()->domain() != nullptr) {
                IntSetVal* domain = eval_intset(env, ident->decl()->ti()->domain());
                IntSetRanges dr(domain);
                IntSetRanges ibr(newdom);
                Ranges::Inter<IntVal, IntSetRanges, IntSetRanges> i(dr, ibr);
                IntSetVal* newibv = IntSetVal::ai(i);
                if (domain->card() != newibv->card()) {
                  newdom = newibv;
                  changeDom = true;
                }
              } else {
                changeDom = true;
              }
              if (ident->type().st() == Type::ST_PLAIN && newdom->size() == 0) {
                env.fail();
              } else if (changeDom) {
                set_computed_domain(env, ident->decl(), new SetLit(Location().introduce(), newdom),
                                    false);
                if (ident->decl()->e() == nullptr && newdom->min() == newdom->max() &&
                    !vd->type().isSet()) {
                  ident->decl()->e(IntLit::a(newdom->min()));
                }
              }
              ident =
                  ident->decl()->e() != nullptr ? ident->decl()->e()->dynamicCast<Id>() : nullptr;
            }
          }
          ret.r = bind(env, ctx, r, constants().literalTrue);
          break;
        }
        if (vd->ti()->domain() != nullptr) {
          // check if current domain is already subsumed or falsified by this constraint
          GCLock lock;
          IntSetVal* check_dom = eval_intset(env, e1.r());
          IntSetVal* domain = eval_intset(env, ident->decl()->ti()->domain());
          {
            IntSetRanges cdr(check_dom);
            IntSetRanges dr(domain);
            if (Ranges::subset(dr, cdr)) {
              // the constraint is subsumed
              ret.r = bind(env, ctx, r, constants().literalTrue);
              break;
            }
          }
          if (vd->type().st() == Type::ST_PLAIN) {
            // only for var int (for var set of int, subset can never fail because of the domain)
            IntSetRanges cdr(check_dom);
            IntSetRanges dr(domain);
            if (Ranges::disjoint(cdr, dr)) {
              // the constraint is false
              ret.r = bind(env, ctx, r, constants().literalFalse);
              break;
            }
          }
        }
      }

      std::vector<KeepAlive> args;
      ASTString callid;

      Expression* le0 = nullptr;
      Expression* le1 = nullptr;

      if (boe0->type().isint() && !boe0->type().isOpt() && bot != BOT_IN) {
        le0 = get_linexp<IntLit>(e0.r());
      } else if (boe0->type().isfloat() && !boe0->type().isOpt() && bot != BOT_IN) {
        le0 = get_linexp<FloatLit>(e0.r());
      }
      if (le0 != nullptr) {
        if (boe0->type().isint() && boe1->type().isint() && !boe1->type().isOpt()) {
          le1 = get_linexp<IntLit>(e1.r());
        } else if (boe0->type().isfloat() && boe1->type().isfloat() && !boe1->type().isOpt()) {
          le1 = get_linexp<FloatLit>(e1.r());
        }
      }
      if (le1 != nullptr) {
        if (boe0->type().isint()) {
          flatten_linexp_binop<IntLit>(env, ctx, r, b, ret, le0, le1, bot, doubleNeg, ees, args,
                                       callid);
        } else {
          flatten_linexp_binop<FloatLit>(env, ctx, r, b, ret, le0, le1, bot, doubleNeg, ees, args,
                                         callid);
        }
      } else {
        switch (bot) {
          case BOT_GR:
            std::swap(e0, e1);
            bot = BOT_LE;
            break;
          case BOT_GQ:
            std::swap(e0, e1);
            bot = BOT_LQ;
            break;
          default:
            break;
        }
        args.push_back(e0.r);
        args.push_back(e1.r);
      }

      if (!args.empty()) {
        GC::lock();

        bool idIsOp = false;
        if (callid == "") {
          assert(args.size() == 2);
          if (!isBuiltin) {
            callid = op_to_id(bot);
            idIsOp = true;
          } else {
            callid = op_to_builtin(args[0](), args[1](), bot);
          }
        }

        std::vector<Expression*> args_e(args.size());
        for (auto i = static_cast<unsigned int>(args.size()); (i--) != 0U;) {
          args_e[i] = args[i]();
        }
        Call* cc = new Call(e->loc().introduce(), callid, args_e);
        cc->decl(env.model->matchFn(env, cc->id(), args_e, false));
        if (cc->decl() == nullptr) {
          throw FlatteningError(env, cc->loc(), "cannot find matching declaration");
        }
        if (idIsOp && cc->decl()->e() == nullptr) {
          // This is in fact a built-in operator, but we only found out after
          // constructing the call
          cc = new Call(e->loc().introduce(), op_to_builtin(args[0](), args[1](), bot), args_e);
          cc->decl(env.model->matchFn(env, cc->id(), args_e, false));
          if (cc->decl() == nullptr) {
            throw FlatteningError(env, cc->loc(), "cannot find matching declaration");
          }
        }
        cc->type(cc->decl()->rtype(env, args_e, false));

        // add defines_var annotation if applicable
        Id* assignTo = nullptr;
        if (bot == BOT_EQ && ctx.b == C_ROOT) {
          if ((le0 != nullptr) && le0->isa<Id>()) {
            assignTo = le0->cast<Id>();
          } else if ((le1 != nullptr) && le1->isa<Id>()) {
            assignTo = le1->cast<Id>();
          }
          if (assignTo != nullptr) {
            make_defined_var(assignTo->decl()->flat(), cc);
          }
        }

        auto cit = env.cseMapFind(cc);
        if (cit != env.cseMapEnd()) {
          ees[2].b = cit->second.r();
          if (doubleNeg) {
            Type t = ees[2].b()->type();
            ees[2].b = new UnOp(Location().introduce(), UOT_NOT, ees[2].b());
            ees[2].b()->type(t);
          }
          if (Id* id = ees[2].b()->dynamicCast<Id>()) {
            add_ctx_ann(id->decl(), ctx.b);
          }
          ret.r = conj(env, r, ctx, ees);
          GC::unlock();
        } else {
          bool singleExp = true;
          for (auto& ee : ees) {
            if (!istrue(env, ee.b())) {
              singleExp = false;
              break;
            }
          }
          KeepAlive ka(cc);
          GC::unlock();
          if (singleExp) {
            if (doubleNeg) {
              ctx.b = -ctx.b;
              ctx.neg = !ctx.neg;
            }
            ret.r = flat_exp(env, ctx, cc, r, nullptr).r;
          } else {
            ees[2].b = flat_exp(env, Ctx(), cc, nullptr, nullptr).r;
            if (doubleNeg) {
              GCLock lock;
              Type t = ees[2].b()->type();
              ees[2].b = new UnOp(Location().introduce(), UOT_NOT, ees[2].b());
              ees[2].b()->type(t);
            }
            if (Id* id = ees[2].b()->dynamicCast<Id>()) {
              add_ctx_ann(id->decl(), ctx.b);
            }
            ret.r = conj(env, r, ctx, ees);
          }
        }
      } else {
        ret.r = conj(env, r, ctx, ees);
      }
    } break;

    case BOT_PLUSPLUS: {
      std::vector<EE> ee(2);
      EE eev = flat_exp(env, ctx, boe0, nullptr, nullptr);
      ee[0] = eev;
      ArrayLit* al;
      if (eev.r()->isa<ArrayLit>()) {
        al = eev.r()->cast<ArrayLit>();
      } else {
        Id* id = eev.r()->cast<Id>();
        if (id->decl() == nullptr) {
          throw InternalError("undefined identifier");
        }
        if (id->decl()->e() == nullptr) {
          throw InternalError("array without initialiser not supported");
        }
        al = follow_id(id)->cast<ArrayLit>();
      }
      ArrayLit* al0 = al;
      eev = flat_exp(env, ctx, boe1, nullptr, nullptr);
      ee[1] = eev;
      if (eev.r()->isa<ArrayLit>()) {
        al = eev.r()->cast<ArrayLit>();
      } else {
        Id* id = eev.r()->cast<Id>();
        if (id->decl() == nullptr) {
          throw InternalError("undefined identifier");
        }
        if (id->decl()->e() == nullptr) {
          throw InternalError("array without initialiser not supported");
        }
        al = follow_id(id)->cast<ArrayLit>();
      }
      ArrayLit* al1 = al;
      std::vector<Expression*> v(al0->size() + al1->size());
      for (unsigned int i = al0->size(); (i--) != 0U;) {
        v[i] = (*al0)[i];
      }
      for (unsigned int i = al1->size(); (i--) != 0U;) {
        v[al0->size() + i] = (*al1)[i];
      }
      GCLock lock;
      auto* alret = new ArrayLit(e->loc(), v);
      alret->type(e->type());
      ret.b = conj(env, b, Ctx(), ee);
      ret.r = bind(env, ctx, r, alret);
    } break;
  }
  return ret;
}

}  // namespace MiniZinc