text: /*++
  Copyright (c) 2012 Microsoft Corporation
  
  Module Name:
  
  fpa2bv_converter.cpp
  
  Abstract:
  
  Conversion routines for Floating Point -> Bit-Vector
  
  Author:
  
  Christoph (cwinter) 2012-02-09
  
  Notes:
  
  --*/
  #include<math.h>
  
  #include "ast/ast_smt2_pp.h"
  #include "ast/well_sorted.h"
  #include "ast/rewriter/th_rewriter.h"
  
  #include "ast/fpa/fpa2bv_converter.h"
  #include "ast/rewriter/fpa_rewriter.h"
  
  #define BVULT(X,Y,R) { expr_ref t(m); t = m_bv_util.mk_ule(Y,X); m_simp.mk_not(t, R); }
  
  fpa2bv_converter::fpa2bv_converter(ast_manager & m) :
      m(m),
      m_simp(m),
      m_util(m),
      m_bv_util(m),
      m_arith_util(m),
      m_dt_util(m),
      m_seq_util(m),
      m_mpf_manager(m_util.fm()),
      m_mpz_manager(m_mpf_manager.mpz_manager()),
      m_hi_fp_unspecified(true),
      m_extra_assertions(m) {
      m_plugin = static_cast<fpa_decl_plugin*>(m.get_plugin(m.mk_family_id("fpa")));
  }
  
  fpa2bv_converter::~fpa2bv_converter() {
      reset();
  }
  
  void fpa2bv_converter::mk_eq(expr * a, expr * b, expr_ref & result) {
      if (is_float(a) && is_float(b)) {
          SASSERT(m_util.is_fp(a) && m_util.is_fp(b));
  
          TRACE("fpa2bv", tout << "mk_eq a=" << mk_ismt2_pp(a, m) << std::endl;
                          tout << "mk_eq b=" << mk_ismt2_pp(b, m) << std::endl;);
  
          expr_ref eq_sgn(m), eq_exp(m), eq_sig(m);
          m_simp.mk_eq(to_app(a)->get_arg(0), to_app(b)->get_arg(0), eq_sgn);
          m_simp.mk_eq(to_app(a)->get_arg(1), to_app(b)->get_arg(1), eq_exp);
          m_simp.mk_eq(to_app(a)->get_arg(2), to_app(b)->get_arg(2), eq_sig);
  
          dbg_decouple("fpa2bv_eq_sgn", eq_sgn);
          dbg_decouple("fpa2bv_eq_exp", eq_exp);
          dbg_decouple("fpa2bv_eq_sig", eq_sig);
  
          expr_ref both_the_same(m);
          m_simp.mk_and(eq_sgn, eq_exp, eq_sig, both_the_same);
          dbg_decouple("fpa2bv_eq_both_the_same", both_the_same);
  
          // The SMT FPA theory asks for _one_ NaN value, but the bit-blasting
          // has many, like IEEE754. This encoding of equality makes it look like
          // a single NaN again.
          expr_ref a_is_nan(m), b_is_nan(m), both_are_nan(m);
          mk_is_nan(a, a_is_nan);
          mk_is_nan(b, b_is_nan);
          m_simp.mk_and(a_is_nan, b_is_nan, both_are_nan);
          dbg_decouple("fpa2bv_eq_both_are_nan", both_are_nan);
  
          m_simp.mk_or(both_are_nan, both_the_same, result);
      }
      else if (is_rm(a) && is_rm(b)) {
          SASSERT(m_util.is_bv2rm(b) && m_util.is_bv2rm(a));
  
          TRACE("fpa2bv", tout << "mk_eq_rm a=" << mk_ismt2_pp(a, m) << std::endl;
                          tout << "mk_eq_rm b=" << mk_ismt2_pp(b, m) << std::endl;);
  
          m_simp.mk_eq(to_app(a)->get_arg(0), to_app(b)->get_arg(0), result);
      }
      else
          UNREACHABLE();
  }
  
  void fpa2bv_converter::mk_ite(expr * c, expr * t, expr * f, expr_ref & result) {
      if (m_util.is_fp(t) && m_util.is_fp(f)) {
          expr *t_sgn, *t_sig, *t_exp;
          expr *f_sgn, *f_sig, *f_exp;
          split_fp(t, t_sgn, t_exp, t_sig);
          split_fp(f, f_sgn, f_exp, f_sig);
  
          expr_ref sgn(m), s(m), e(m);
          m_simp.mk_ite(c, t_sgn, f_sgn, sgn);
          m_simp.mk_ite(c, t_sig, f_sig, s);
          m_simp.mk_ite(c, t_exp, f_exp, e);
  
          result = m_util.mk_fp(sgn, e, s);
      }
      else if (m_util.is_rm(t) && m_util.is_rm(f))
      {
          SASSERT(m_util.is_bv2rm(t) && m_util.is_bv2rm(f));
          TRACE("fpa2bv", tout << "ite rm: t=" << mk_ismt2_pp(t, m) << " f=" << mk_ismt2_pp(f, m) << std::endl; );
          m_simp.mk_ite(c, to_app(t)->get_arg(0), to_app(f)->get_arg(0), result);
          result = m_util.mk_bv2rm(result);
      }
      else
          UNREACHABLE();
  }
  
  void fpa2bv_converter::mk_distinct(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      // Note: in SMT there is only one NaN, so multiple of them are considered
      // equal, thus (distinct NaN NaN) is false, even if the two NaNs have
      // different bitwise representations (see also mk_eq).
      result = m.mk_true();
      for (unsigned i = 0; i < num; i++) {
          for (unsigned j = i+1; j < num; j++) {
              expr_ref eq(m), neq(m);
              mk_eq(args[i], args[j], eq);
              neq = m.mk_not(eq);
              m_simp.mk_and(result, neq, result);
          }
      }
  }
  
  void fpa2bv_converter::mk_numeral(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 0);
      SASSERT(f->get_num_parameters() == 1);
      SASSERT(f->get_parameter(0).is_external());
      unsigned p_id = f->get_parameter(0).get_ext_id();
      mpf const & v = m_plugin->get_value(p_id);
      mk_numeral(f->get_range(), v, result);
  }
  
  void fpa2bv_converter::mk_numeral(sort * s, mpf const & v, expr_ref & result) {
      unsigned sbits = v.get_sbits();
      unsigned ebits = v.get_ebits();
  
      bool sign = m_util.fm().sgn(v);
      mpz const & sig = m_util.fm().sig(v);
      mpf_exp_t const & exp = m_util.fm().exp(v);
  
      if (m_util.fm().is_nan(v))
          mk_nan(s, result);
      else if (m_util.fm().is_inf(v)) {
          if (m_util.fm().sgn(v))
              mk_ninf(s, result);
          else
              mk_pinf(s, result);
      }
      else {
          expr_ref bv_sgn(m), bv_sig(m), e(m), biased_exp(m);
          bv_sgn = m_bv_util.mk_numeral((sign) ? 1 : 0, 1);
          bv_sig = m_bv_util.mk_numeral(rational(sig), sbits-1);
          e = m_bv_util.mk_numeral(exp, ebits);
  
          mk_bias(e, biased_exp);
  
          result = m_util.mk_fp(bv_sgn, biased_exp, bv_sig);
          TRACE("fpa2bv_dbg", tout << "value of [" << sign << " " << m_mpz_manager.to_string(sig) << " " << exp << "] is "
              << mk_ismt2_pp(result, m) << std::endl;);
      }
  }
  
  app * fpa2bv_converter::mk_fresh_const(char const * prefix, unsigned sz) {
      return m.mk_fresh_const(prefix, m_bv_util.mk_sort(sz));
  }
  
  void fpa2bv_converter::mk_const(func_decl * f, expr_ref & result) {
      SASSERT(f->get_family_id() == null_family_id);
      SASSERT(f->get_arity() == 0);
      expr * r;
      if (m_const2bv.find(f, r)) {
          result = r;
      }
      else {
          sort * srt = f->get_range();
          SASSERT(is_float(srt));
          unsigned ebits = m_util.get_ebits(srt);
          unsigned sbits = m_util.get_sbits(srt);
  
          app_ref sgn(m), s(m), e(m);
  
  #ifdef Z3DEBUG
          std::string p("fpa2bv");
          std::string name = f->get_name().str();
  
          sgn = mk_fresh_const((p + "_sgn_" + name).c_str(), 1);
          e = mk_fresh_const((p + "_exp_" + name).c_str(), ebits);
          s = mk_fresh_const((p + "_sig_" + name).c_str(), sbits-1);
  #else
          app_ref bv(m);
          unsigned bv_sz = 1 + ebits + (sbits - 1);
          bv = mk_fresh_const(nullptr, bv_sz);
  
          sgn = m_bv_util.mk_extract(bv_sz - 1, bv_sz - 1, bv);
          e = m_bv_util.mk_extract(bv_sz - 2, sbits - 1, bv);
          s = m_bv_util.mk_extract(sbits - 2, 0, bv);
  
          SASSERT(m_bv_util.get_bv_size(sgn) == 1);
          SASSERT(m_bv_util.get_bv_size(s) == sbits-1);
          SASSERT(m_bv_util.get_bv_size(e) == ebits);
  #endif
  
          result = m_util.mk_fp(sgn, e, s);
  
          m_const2bv.insert(f, result);
          m.inc_ref(f);
          m.inc_ref(result);
      }
  }
  
  void fpa2bv_converter::mk_var(unsigned base_inx, sort * srt, expr_ref & result) {
      SASSERT(is_float(srt));
      unsigned ebits = m_util.get_ebits(srt);
      unsigned sbits = m_util.get_sbits(srt);
  
      expr_ref sgn(m), s(m), e(m);
  
      sgn = m.mk_var(base_inx, m_bv_util.mk_sort(1));
      s = m.mk_var(base_inx+1, m_bv_util.mk_sort(sbits-1));
      e = m.mk_var(base_inx+2, m_bv_util.mk_sort(ebits));
  
      result = m_util.mk_fp(sgn, e, s);
  }
  
  void fpa2bv_converter::mk_uf(func_decl * f, unsigned num, expr * const * args, expr_ref & result)
  {
      TRACE("fpa2bv", tout << "UF: " << mk_ismt2_pp(f, m) << std::endl; );
  
      expr_ref fapp(m), feq(m);
      sort_ref rng(m);
      app_ref bv_app(m), flt_app(m);
      rng = f->get_range();
      fapp = m.mk_app(f, num, args);
      if (m_util.is_float(rng)) {
          sort_ref bv_rng(m);
          expr_ref new_eq(m);
          unsigned ebits = m_util.get_ebits(rng);
          unsigned sbits = m_util.get_sbits(rng);
          unsigned bv_sz = ebits+sbits;
          bv_rng = m_bv_util.mk_sort(bv_sz);
          func_decl * bv_f = mk_bv_uf(f, f->get_domain(), bv_rng);
          bv_app = m.mk_app(bv_f, num, args);
          flt_app = m_util.mk_fp(m_bv_util.mk_extract(bv_sz-1, bv_sz-1, bv_app),
                                 m_bv_util.mk_extract(sbits+ebits-2, sbits-1, bv_app),
                                 m_bv_util.mk_extract(sbits-2, 0, bv_app));
          new_eq = m.mk_eq(fapp, flt_app);
          m_extra_assertions.push_back(new_eq);
          result = flt_app;
      }
      else if (m_util.is_rm(rng)) {
          sort_ref bv_rng(m);
          expr_ref new_eq(m);
          bv_rng = m_bv_util.mk_sort(3);
          func_decl * bv_f = mk_bv_uf(f, f->get_domain(), bv_rng);
          bv_app = m.mk_app(bv_f, num, args);
          flt_app = m_util.mk_bv2rm(bv_app);
          new_eq = m.mk_eq(fapp, flt_app);
          m_extra_assertions.push_back(new_eq);
          result = flt_app;
      }
      else
          result = fapp;
  
      TRACE("fpa2bv", tout << "UF result: " << mk_ismt2_pp(result, m) << std::endl; );
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_rm_const(func_decl * f, expr_ref & result) {
      SASSERT(f->get_family_id() == null_family_id);
      SASSERT(f->get_arity() == 0);
      expr * r;
      if (m_rm_const2bv.find(f, r)) {
          result = r;
      }
      else {
          SASSERT(is_rm(f->get_range()));
  
          expr_ref bv3(m);
          bv3 = m.mk_fresh_const(
  #ifdef Z3DEBUG
              "fpa2bv_rm"
  #else
              nullptr
  #endif
              , m_bv_util.mk_sort(3));
  
          result = m_util.mk_bv2rm(bv3);
          m_rm_const2bv.insert(f, result);
          m.inc_ref(f);
          m.inc_ref(result);
  
          expr_ref rcc(m);
          rcc = bu().mk_ule(bv3, bu().mk_numeral(4, 3));
          m_extra_assertions.push_back(rcc);
      }
  }
  
  void fpa2bv_converter::mk_pinf(func_decl * f, expr_ref & result) {
      mk_pinf(f->get_range(), result);
  }
  
  void fpa2bv_converter::mk_pinf(sort * s, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      expr_ref top_exp(m);
      mk_top_exp(ebits, top_exp);
      result = m_util.mk_fp(m_bv_util.mk_numeral(0, 1), top_exp, m_bv_util.mk_numeral(0, sbits-1));
  }
  
  void fpa2bv_converter::mk_ninf(func_decl * f, expr_ref & result) {
      mk_ninf(f->get_range(), result);
  }
  
  void fpa2bv_converter::mk_ninf(sort * s, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      expr_ref top_exp(m);
      mk_top_exp(ebits, top_exp);
      result = m_util.mk_fp(m_bv_util.mk_numeral(1, 1), top_exp, m_bv_util.mk_numeral(0, sbits-1));
  }
  
  void fpa2bv_converter::mk_nan(func_decl * f, expr_ref & result) {
      mk_nan(f->get_range(), result);
  }
  
  void fpa2bv_converter::mk_nan(sort * s, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      expr_ref top_exp(m);
      mk_top_exp(ebits, top_exp);
      result = m_util.mk_fp(m_bv_util.mk_numeral(0, 1), top_exp, m_bv_util.mk_numeral(1, sbits - 1));
  }
  
  void fpa2bv_converter::mk_nzero(func_decl * f, expr_ref & result) {
      mk_nzero(f->get_range(), result);
  }
  
  void fpa2bv_converter::mk_nzero(sort * s, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      expr_ref bot_exp(m);
      mk_bot_exp(ebits, bot_exp);
      result = m_util.mk_fp(m_bv_util.mk_numeral(1, 1), bot_exp, m_bv_util.mk_numeral(0, sbits - 1));
  }
  
  void fpa2bv_converter::mk_pzero(func_decl * f, expr_ref & result) {
      mk_pzero(f->get_range(), result);
  }
  
  void fpa2bv_converter::mk_pzero(sort * s, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      expr_ref bot_exp(m);
      mk_bot_exp(ebits, bot_exp);
      result = m_util.mk_fp(m_bv_util.mk_numeral(0, 1), bot_exp, m_bv_util.mk_numeral(0, sbits-1));
  }
  
  void fpa2bv_converter::mk_zero(sort * s, expr_ref & sgn, expr_ref & result) {
      expr_ref is_pos(m), pzero(m), nzero(m);
      is_pos = m.mk_eq(sgn, m_bv_util.mk_numeral(0, 1));
      mk_pzero(s, pzero);
      mk_nzero(s, nzero);
      mk_ite(is_pos, pzero, nzero, result);
  }
  
  void fpa2bv_converter::mk_one(func_decl * f, expr_ref & sign, expr_ref & result) {
      mk_one(f->get_range(), sign, result);
  }
  
  void fpa2bv_converter::mk_one(sort * s, expr_ref & sign, expr_ref & result) {
      SASSERT(is_float(s));
      unsigned sbits = m_util.get_sbits(s);
      unsigned ebits = m_util.get_ebits(s);
      result = m_util.mk_fp(sign, m_bv_util.mk_numeral(fu().fm().m_powers2.m1(ebits-1), ebits), m_bv_util.mk_numeral(0, sbits-1));
  }
  
  void fpa2bv_converter::add_core(unsigned sbits, unsigned ebits,
      expr_ref & c_sgn, expr_ref & c_sig, expr_ref & c_exp, expr_ref & d_sgn, expr_ref & d_sig, expr_ref & d_exp,
      expr_ref & res_sgn, expr_ref & res_sig, expr_ref & res_exp)
  {
      // c/d are now such that c_exp >= d_exp.
      expr_ref exp_delta(m);
      exp_delta = m_bv_util.mk_bv_sub(c_exp, d_exp);
  
      dbg_decouple("fpa2bv_add_exp_delta", exp_delta);
  
      if (log2(sbits + 2) < ebits + 2)
      {
          // cap the delta
          expr_ref cap(m), cap_le_delta(m), exp_delta_ext(m);
          cap = m_bv_util.mk_numeral(sbits + 2, ebits + 2);
          cap_le_delta = m_bv_util.mk_ule(cap, m_bv_util.mk_zero_extend(2, exp_delta));
          exp_delta_ext = m_bv_util.mk_zero_extend(2, exp_delta);
          m_simp.mk_ite(cap_le_delta, cap, exp_delta_ext, exp_delta);
          exp_delta = m_bv_util.mk_extract(ebits - 1, 0, exp_delta);
          dbg_decouple("fpa2bv_add_exp_cap", cap);
      }
  
      dbg_decouple("fpa2bv_add_exp_delta_capped", exp_delta);
  
      // Three extra bits for c/d
      c_sig = m_bv_util.mk_concat(c_sig, m_bv_util.mk_numeral(0, 3));
      d_sig = m_bv_util.mk_concat(d_sig, m_bv_util.mk_numeral(0, 3));
  
      SASSERT(is_well_sorted(m, c_sig));
      SASSERT(is_well_sorted(m, d_sig));
  
      // Alignment shift with sticky bit computation.
      expr_ref big_d_sig(m);
      big_d_sig = m_bv_util.mk_concat(d_sig, m_bv_util.mk_numeral(0, sbits+3));
  
      SASSERT(is_well_sorted(m, big_d_sig));
  
      expr_ref shifted_big(m), shifted_d_sig(m), sticky_raw(m), sticky(m);
      shifted_big = m_bv_util.mk_bv_lshr(big_d_sig, m_bv_util.mk_concat(m_bv_util.mk_numeral(0, (2*(sbits+3))-ebits), exp_delta));
      shifted_d_sig = m_bv_util.mk_extract((2*(sbits+3)-1), (sbits+3), shifted_big);
      SASSERT(is_well_sorted(m, shifted_d_sig));
  
      sticky_raw = m_bv_util.mk_extract(sbits+2, 0, shifted_big);
      expr_ref sticky_eq(m), nil_sbit3(m), one_sbit3(m);
      nil_sbit3 = m_bv_util.mk_numeral(0, sbits+3);
      one_sbit3 = m_bv_util.mk_numeral(1, sbits+3);
      m_simp.mk_eq(sticky_raw, nil_sbit3, sticky_eq);
      m_simp.mk_ite(sticky_eq, nil_sbit3, one_sbit3, sticky);
      SASSERT(is_well_sorted(m, sticky));
  
      expr * or_args[2] = { shifted_d_sig, sticky };
      shifted_d_sig = m_bv_util.mk_bv_or(2, or_args);
      SASSERT(is_well_sorted(m, shifted_d_sig));
  
      expr_ref eq_sgn(m);
      m_simp.mk_eq(c_sgn, d_sgn, eq_sgn);
  
      dbg_decouple("fpa2bv_add_eq_sgn", eq_sgn);
      TRACE("fpa2bv_add_core", tout << "EQ_SGN = " << mk_ismt2_pp(eq_sgn, m) << std::endl; );
  
      // two extra bits for catching the overflow.
      c_sig = m_bv_util.mk_zero_extend(2, c_sig);
      shifted_d_sig = m_bv_util.mk_zero_extend(2, shifted_d_sig);
  
      SASSERT(m_bv_util.get_bv_size(c_sig) == sbits+5);
      SASSERT(m_bv_util.get_bv_size(shifted_d_sig) == sbits+5);
  
      dbg_decouple("fpa2bv_add_c_sig", c_sig);
      dbg_decouple("fpa2bv_add_shifted_d_sig", shifted_d_sig);
  
      expr_ref sum(m), c_plus_d(m), c_minus_d(m);
      c_plus_d = m_bv_util.mk_bv_add(c_sig, shifted_d_sig);
      c_minus_d = m_bv_util.mk_bv_sub(c_sig, shifted_d_sig);
      m_simp.mk_ite(eq_sgn, c_plus_d, c_minus_d, sum);
  
      SASSERT(is_well_sorted(m, sum));
  
      dbg_decouple("fpa2bv_add_sum", sum);
  
      expr_ref sign_bv(m), n_sum(m);
      sign_bv = m_bv_util.mk_extract(sbits+4, sbits+4, sum);
      n_sum = m_bv_util.mk_bv_neg(sum);
  
      dbg_decouple("fpa2bv_add_sign_bv", sign_bv);
      dbg_decouple("fpa2bv_add_n_sum", n_sum);
  
      family_id bvfid = m_bv_util.get_fid();
  
      expr_ref res_sgn_c1(m), res_sgn_c2(m), res_sgn_c3(m);
      expr_ref not_c_sgn(m), not_d_sgn(m), not_sign_bv(m);
      not_c_sgn = m_bv_util.mk_bv_not(c_sgn);
      not_d_sgn = m_bv_util.mk_bv_not(d_sgn);
      not_sign_bv = m_bv_util.mk_bv_not(sign_bv);
      res_sgn_c1 = m.mk_app(bvfid, OP_BAND, not_c_sgn, d_sgn, sign_bv);
      res_sgn_c2 = m.mk_app(bvfid, OP_BAND, c_sgn, not_d_sgn, not_sign_bv);
      res_sgn_c3 = m.mk_app(bvfid, OP_BAND, c_sgn, d_sgn);
      expr * res_sgn_or_args[3] = { res_sgn_c1, res_sgn_c2, res_sgn_c3 };
      res_sgn = m_bv_util.mk_bv_or(3, res_sgn_or_args);
  
      expr_ref res_sig_eq(m), sig_abs(m), one_1(m);
      one_1 = m_bv_util.mk_numeral(1, 1);
      m_simp.mk_eq(sign_bv, one_1, res_sig_eq);
      m_simp.mk_ite(res_sig_eq, n_sum, sum, sig_abs);
  
      dbg_decouple("fpa2bv_add_sig_abs", sig_abs);
  
      res_sig = m_bv_util.mk_extract(sbits+3, 0, sig_abs);
      res_exp = m_bv_util.mk_sign_extend(2, c_exp); // rounder requires 2 extra bits!
  }
  
  void fpa2bv_converter::mk_add(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 3);
      SASSERT(m_util.is_bv2rm(args[0]));
  
      expr_ref rm(m), x(m), y(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
      y = args[2];
      mk_add(f->get_range(), rm, x, y, result);
  }
  
  void fpa2bv_converter::mk_add(sort * s, expr_ref & rm, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref nan(m), nzero(m), pzero(m);
      mk_nan(s, nan);
      mk_nzero(s, nzero);
      mk_pzero(s, pzero);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_neg(m), x_is_inf(m);
      expr_ref y_is_nan(m), y_is_zero(m), y_is_pos(m), y_is_neg(m), y_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_neg(x, x_is_neg);
      mk_is_inf(x, x_is_inf);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(y, y_is_zero);
      mk_is_pos(y, y_is_pos);
      mk_is_neg(y, y_is_neg);
      mk_is_inf(y, y_is_inf);
  
      dbg_decouple("fpa2bv_add_x_is_nan", x_is_nan);
      dbg_decouple("fpa2bv_add_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_add_x_is_pos", x_is_pos);
      dbg_decouple("fpa2bv_add_x_is_neg", x_is_neg);
      dbg_decouple("fpa2bv_add_x_is_inf", x_is_inf);
      dbg_decouple("fpa2bv_add_y_is_nan", y_is_nan);
      dbg_decouple("fpa2bv_add_y_is_zero", y_is_zero);
      dbg_decouple("fpa2bv_add_y_is_pos", y_is_pos);
      dbg_decouple("fpa2bv_add_y_is_neg", y_is_neg);
      dbg_decouple("fpa2bv_add_y_is_inf", y_is_inf);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m);
  
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      v1 = nan;
  
      mk_is_inf(x, c2);
      expr_ref nx(m), ny(m), nx_xor_ny(m), inf_xor(m);
      mk_is_neg(x, nx);
      mk_is_neg(y, ny);
      m_simp.mk_xor(nx, ny, nx_xor_ny);
      m_simp.mk_and(y_is_inf, nx_xor_ny, inf_xor);
      mk_ite(inf_xor, nan, x, v2);
  
      mk_is_inf(y, c3);
      expr_ref xy_is_neg(m), v3_and(m);
      m_simp.mk_xor(x_is_neg, y_is_neg, xy_is_neg);
      m_simp.mk_and(x_is_inf, xy_is_neg, v3_and);
      mk_ite(v3_and, nan, y, v3);
  
      expr_ref rm_is_to_neg(m), signs_and(m), signs_xor(m), v4_and(m), rm_and_xor(m), neg_cond(m);
      m_simp.mk_and(x_is_zero, y_is_zero, c4);
      m_simp.mk_and(x_is_neg, y_is_neg, signs_and);
      m_simp.mk_xor(x_is_neg, y_is_neg, signs_xor);
      mk_is_rm(rm, BV_RM_TO_NEGATIVE, rm_is_to_neg);
      m_simp.mk_and(rm_is_to_neg, signs_xor, rm_and_xor);
      m_simp.mk_or(signs_and, rm_and_xor, neg_cond);
      mk_ite(neg_cond, nzero, pzero, v4);
      m_simp.mk_and(x_is_neg, y_is_neg, v4_and);
      mk_ite(v4_and, x, v4, v4);
  
      c5 = x_is_zero;
      v5 = y;
  
      c6 = y_is_zero;
      v6 = x;
  
      // Actual addition.
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m), b_sgn(m), b_sig(m), b_exp(m), b_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, false);
      unpack(y, b_sgn, b_sig, b_exp, b_lz, false);
  
      dbg_decouple("fpa2bv_add_unpack_a_sgn", a_sgn);
      dbg_decouple("fpa2bv_add_unpack_a_sig", a_sig);
      dbg_decouple("fpa2bv_add_unpack_a_exp", a_exp);
      dbg_decouple("fpa2bv_add_unpack_b_sgn", b_sgn);
      dbg_decouple("fpa2bv_add_unpack_b_sig", b_sig);
      dbg_decouple("fpa2bv_add_unpack_b_exp", b_exp);
  
      expr_ref swap_cond(m);
      swap_cond = m_bv_util.mk_sle(a_exp, b_exp);
  
      expr_ref c_sgn(m), c_sig(m), c_exp(m), d_sgn(m), d_sig(m), d_exp(m);
      m_simp.mk_ite(swap_cond, b_sgn, a_sgn, c_sgn);
      m_simp.mk_ite(swap_cond, b_sig, a_sig, c_sig); // has sbits
      m_simp.mk_ite(swap_cond, b_exp, a_exp, c_exp); // has ebits
      m_simp.mk_ite(swap_cond, a_sgn, b_sgn, d_sgn);
      m_simp.mk_ite(swap_cond, a_sig, b_sig, d_sig); // has sbits
      m_simp.mk_ite(swap_cond, a_exp, b_exp, d_exp); // has ebits
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
      add_core(sbits, ebits,
          c_sgn, c_sig, c_exp, d_sgn, d_sig, d_exp,
          res_sgn, res_sig, res_exp);
  
      expr_ref is_zero_sig(m), nil_sbit4(m);
      nil_sbit4 = m_bv_util.mk_numeral(0, sbits+4);
      m_simp.mk_eq(res_sig, nil_sbit4, is_zero_sig);
  
      SASSERT(is_well_sorted(m, is_zero_sig));
  
      dbg_decouple("fpa2bv_add_is_zero_sig", is_zero_sig);
  
      expr_ref zero_case(m);
      mk_ite(rm_is_to_neg, nzero, pzero, zero_case);
  
      expr_ref rounded(m);
      round(s, rm, res_sgn, res_sig, res_exp, rounded);
  
      mk_ite(is_zero_sig, zero_case, rounded, v7);
  
      mk_ite(c6, v6, v7, result);
      mk_ite(c5, v5, result, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_add", tout << "ADD = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_sub(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 3);
      expr_ref rm(m), x(m), y(m);
      rm = args[0];
      x = args[1];
      y = args[2];
      mk_sub(f->get_range(), rm, x, y, result);
  }
  
  void fpa2bv_converter::mk_sub(sort * s, expr_ref & rm, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref t(m);
      mk_neg(s, y, t);
      mk_add(s, rm, x, t, result);
  }
  
  void fpa2bv_converter::mk_neg(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref x(m);
      x = args[0];
      mk_neg(f->get_range(), x, result);
  }
  
  void fpa2bv_converter::mk_neg(sort * srt, expr_ref & x, expr_ref & result) {
      expr * sgn, *sig, *e;
      split_fp(x, sgn, e, sig);
      expr_ref c(m), nsgn(m);
      mk_is_nan(x, c);
      nsgn = m_bv_util.mk_bv_not(sgn);
      expr_ref r_sgn(m);
      m_simp.mk_ite(c, sgn, nsgn, r_sgn);
      result = m_util.mk_fp(r_sgn, e, sig);
  }
  
  void fpa2bv_converter::mk_mul(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 3);
      SASSERT(m_util.is_bv2rm(args[0]));
  
      expr_ref rm(m), x(m), y(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
      y = args[2];
      mk_mul(f->get_range(), rm, x, y, result);
  }
  
  void fpa2bv_converter::mk_mul(sort * s, expr_ref & rm, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(s, nan);
      mk_nzero(s, nzero);
      mk_pzero(s, pzero);
      mk_ninf(s, ninf);
      mk_pinf(s, pinf);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_inf(m);
      expr_ref y_is_nan(m), y_is_zero(m), y_is_pos(m), y_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_inf(x, x_is_inf);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(y, y_is_zero);
      mk_is_pos(y, y_is_pos);
      mk_is_inf(y, y_is_inf);
  
      dbg_decouple("fpa2bv_mul_x_is_nan", x_is_nan);
      dbg_decouple("fpa2bv_mul_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_mul_x_is_pos", x_is_pos);
      dbg_decouple("fpa2bv_mul_x_is_inf", x_is_inf);
      dbg_decouple("fpa2bv_mul_y_is_nan", y_is_nan);
      dbg_decouple("fpa2bv_mul_y_is_zero", y_is_zero);
      dbg_decouple("fpa2bv_mul_y_is_pos", y_is_pos);
      dbg_decouple("fpa2bv_mul_y_is_inf", y_is_inf);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m);
  
      // (x is NaN) || (y is NaN) -> NaN
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      v1 = nan;
  
      // (x is +oo) -> if (y is 0) then NaN else inf with y's sign.
      mk_is_pinf(x, c2);
      expr_ref y_sgn_inf(m);
      mk_ite(y_is_pos, pinf, ninf, y_sgn_inf);
      mk_ite(y_is_zero, nan, y_sgn_inf, v2);
  
      // (y is +oo) -> if (x is 0) then NaN else inf with x's sign.
      mk_is_pinf(y, c3);
      expr_ref x_sgn_inf(m);
      mk_ite(x_is_pos, pinf, ninf, x_sgn_inf);
      mk_ite(x_is_zero, nan, x_sgn_inf, v3);
  
      // (x is -oo) -> if (y is 0) then NaN else inf with -y's sign.
      mk_is_ninf(x, c4);
      expr_ref neg_y_sgn_inf(m);
      mk_ite(y_is_pos, ninf, pinf, neg_y_sgn_inf);
      mk_ite(y_is_zero, nan, neg_y_sgn_inf, v4);
  
      // (y is -oo) -> if (x is 0) then NaN else inf with -x's sign.
      mk_is_ninf(y, c5);
      expr_ref neg_x_sgn_inf(m);
      mk_ite(x_is_pos, ninf, pinf, neg_x_sgn_inf);
      mk_ite(x_is_zero, nan, neg_x_sgn_inf, v5);
  
      // (x is 0) || (y is 0) -> x but with sign = x.sign ^ y.sign
      m_simp.mk_or(x_is_zero, y_is_zero, c6);
      expr_ref sign_xor(m);
      m_simp.mk_xor(x_is_pos, y_is_pos, sign_xor);
      mk_ite(sign_xor, nzero, pzero, v6);
  
      // else comes the actual multiplication.
      unsigned sbits = m_util.get_sbits(s);
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m), b_sgn(m), b_sig(m), b_exp(m), b_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
      unpack(y, b_sgn, b_sig, b_exp, b_lz, true);
  
      dbg_decouple("fpa2bv_mul_a_sig", a_sig);
      dbg_decouple("fpa2bv_mul_a_exp", a_exp);
      dbg_decouple("fpa2bv_mul_b_sig", b_sig);
      dbg_decouple("fpa2bv_mul_b_exp", b_exp);
  
      expr_ref a_lz_ext(m), b_lz_ext(m);
      a_lz_ext = m_bv_util.mk_zero_extend(2, a_lz);
      b_lz_ext = m_bv_util.mk_zero_extend(2, b_lz);
  
      dbg_decouple("fpa2bv_mul_lz_a", a_lz);
      dbg_decouple("fpa2bv_mul_lz_b", b_lz);
  
      expr_ref a_sig_ext(m), b_sig_ext(m);
      a_sig_ext = m_bv_util.mk_zero_extend(sbits, a_sig);
      b_sig_ext = m_bv_util.mk_zero_extend(sbits, b_sig);
  
      expr_ref a_exp_ext(m), b_exp_ext(m);
      a_exp_ext = m_bv_util.mk_sign_extend(2, a_exp);
      b_exp_ext = m_bv_util.mk_sign_extend(2, b_exp);
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
      expr * signs[2] = { a_sgn, b_sgn };
      res_sgn = m_bv_util.mk_bv_xor(2, signs);
  
      dbg_decouple("fpa2bv_mul_res_sgn", res_sgn);
  
      res_exp = m_bv_util.mk_bv_add(
          m_bv_util.mk_bv_sub(a_exp_ext, a_lz_ext),
          m_bv_util.mk_bv_sub(b_exp_ext, b_lz_ext));
  
      expr_ref product(m);
      product = m_bv_util.mk_bv_mul(a_sig_ext, b_sig_ext);
  
      dbg_decouple("fpa2bv_mul_product", product);
  
      SASSERT(m_bv_util.get_bv_size(product) == 2*sbits);
  
      expr_ref h_p(m), l_p(m), rbits(m);
      h_p = m_bv_util.mk_extract(2*sbits-1, sbits, product);
      l_p = m_bv_util.mk_extract(sbits-1, 0, product);
  
      if (sbits >= 4) {
          expr_ref sticky(m);
          sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, m_bv_util.mk_extract(sbits-4, 0, product));
          rbits = m_bv_util.mk_concat(m_bv_util.mk_extract(sbits-1, sbits-3, product), sticky);
      }
      else
          rbits = m_bv_util.mk_concat(l_p, m_bv_util.mk_numeral(0, 4 - sbits));
  
      SASSERT(m_bv_util.get_bv_size(rbits) == 4);
      res_sig = m_bv_util.mk_concat(h_p, rbits);
  
      round(s, rm, res_sgn, res_sig, res_exp, v7);
  
      // And finally, we tie them together.
      mk_ite(c6, v6, v7, result);
      mk_ite(c5, v5, result, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_mul", tout << "MUL = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_div(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 3);
      SASSERT(m_util.is_bv2rm(args[0]));
      expr_ref rm(m), x(m), y(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
      y = args[2];
      mk_div(f->get_range(), rm, x, y, result);
  }
  
  void fpa2bv_converter::mk_div(sort * s, expr_ref & rm, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(s, nan);
      mk_nzero(s, nzero);
      mk_pzero(s, pzero);
      mk_ninf(s, ninf);
      mk_pinf(s, pinf);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_inf(m);
      expr_ref y_is_nan(m), y_is_zero(m), y_is_pos(m), y_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_inf(x, x_is_inf);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(y, y_is_zero);
      mk_is_pos(y, y_is_pos);
      mk_is_inf(y, y_is_inf);
  
      dbg_decouple("fpa2bv_div_x_is_nan", x_is_nan);
      dbg_decouple("fpa2bv_div_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_div_x_is_pos", x_is_pos);
      dbg_decouple("fpa2bv_div_x_is_inf", x_is_inf);
      dbg_decouple("fpa2bv_div_y_is_nan", y_is_nan);
      dbg_decouple("fpa2bv_div_y_is_zero", y_is_zero);
      dbg_decouple("fpa2bv_div_y_is_pos", y_is_pos);
      dbg_decouple("fpa2bv_div_y_is_inf", y_is_inf);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m), c7(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m), v8(m);
  
      // (x is NaN) || (y is NaN) -> NaN
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      v1 = nan;
  
      // (x is +oo) -> if (y is oo) then NaN else inf with y's sign.
      mk_is_pinf(x, c2);
      expr_ref y_sgn_inf(m);
      mk_ite(y_is_pos, pinf, ninf, y_sgn_inf);
      mk_ite(y_is_inf, nan, y_sgn_inf, v2);
  
      // (y is +oo) -> if (x is oo) then NaN else 0 with sign x.sgn ^ y.sgn
      mk_is_pinf(y, c3);
      expr_ref xy_zero(m), signs_xor(m);
      m_simp.mk_xor(x_is_pos, y_is_pos, signs_xor);
      mk_ite(signs_xor, nzero, pzero, xy_zero);
      mk_ite(x_is_inf, nan, xy_zero, v3);
  
      // (x is -oo) -> if (y is oo) then NaN else inf with -y's sign.
      mk_is_ninf(x, c4);
      expr_ref neg_y_sgn_inf(m);
      mk_ite(y_is_pos, ninf, pinf, neg_y_sgn_inf);
      mk_ite(y_is_inf, nan, neg_y_sgn_inf, v4);
  
      // (y is -oo) -> if (x is oo) then NaN else 0 with sign x.sgn ^ y.sgn
      mk_is_ninf(y, c5);
      mk_ite(x_is_inf, nan, xy_zero, v5);
  
      // (y is 0) -> if (x is 0) then NaN else inf with xor sign.
      c6 = y_is_zero;
      expr_ref sgn_inf(m);
      mk_ite(signs_xor, ninf, pinf, sgn_inf);
      mk_ite(x_is_zero, nan, sgn_inf, v6);
  
      // (x is 0) -> result is zero with sgn = x.sgn^y.sgn
      // This is a special case to avoid problems with the unpacking of zero.
      c7 = x_is_zero;
      mk_ite(signs_xor, nzero, pzero, v7);
  
      // else comes the actual division.
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
      SASSERT(ebits <= sbits);
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m), b_sgn(m), b_sig(m), b_exp(m), b_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
      unpack(y, b_sgn, b_sig, b_exp, b_lz, true);
  
      unsigned extra_bits = sbits+2;
      expr_ref a_sig_ext(m), b_sig_ext(m);
      a_sig_ext = m_bv_util.mk_concat(a_sig, m_bv_util.mk_numeral(0, sbits + extra_bits));
      b_sig_ext = m_bv_util.mk_zero_extend(sbits + extra_bits, b_sig);
  
      expr_ref a_exp_ext(m), b_exp_ext(m);
      a_exp_ext = m_bv_util.mk_sign_extend(2, a_exp);
      b_exp_ext = m_bv_util.mk_sign_extend(2, b_exp);
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
      expr * signs[2] = { a_sgn, b_sgn };
      res_sgn = m_bv_util.mk_bv_xor(2, signs);
  
      expr_ref a_lz_ext(m), b_lz_ext(m);
      a_lz_ext = m_bv_util.mk_zero_extend(2, a_lz);
      b_lz_ext = m_bv_util.mk_zero_extend(2, b_lz);
  
      res_exp = m_bv_util.mk_bv_sub(
          m_bv_util.mk_bv_sub(a_exp_ext, a_lz_ext),
          m_bv_util.mk_bv_sub(b_exp_ext, b_lz_ext));
  
      expr_ref quotient(m);
      // b_sig_ext can't be 0 here, so it's safe to use OP_BUDIV_I
      quotient = m.mk_app(m_bv_util.get_fid(), OP_BUDIV_I, a_sig_ext, b_sig_ext);
  
      dbg_decouple("fpa2bv_div_quotient", quotient);
  
      SASSERT(m_bv_util.get_bv_size(quotient) == (sbits + sbits + extra_bits));
  
      expr_ref sticky(m);
      sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, m_bv_util.mk_extract(extra_bits-2, 0, quotient));
      res_sig = m_bv_util.mk_concat(m_bv_util.mk_extract(extra_bits+sbits+1, extra_bits-1, quotient), sticky);
  
      SASSERT(m_bv_util.get_bv_size(res_sig) == (sbits + 4));
  
      expr_ref res_sig_lz(m);
      mk_leading_zeros(res_sig, sbits + 4, res_sig_lz);
      dbg_decouple("fpa2bv_div_res_sig_lz", res_sig_lz);
      expr_ref res_sig_shift_amount(m);
      res_sig_shift_amount = m_bv_util.mk_bv_sub(res_sig_lz, m_bv_util.mk_numeral(1, sbits + 4));
      dbg_decouple("fpa2bv_div_res_sig_shift_amount", res_sig_shift_amount);
      expr_ref shift_cond(m);
      shift_cond = m_bv_util.mk_ule(res_sig_lz, m_bv_util.mk_numeral(1, sbits + 4));
      expr_ref res_sig_shifted(m), res_exp_shifted(m);
      res_sig_shifted = m_bv_util.mk_bv_shl(res_sig, res_sig_shift_amount);
      res_exp_shifted = m_bv_util.mk_bv_sub(res_exp, m_bv_util.mk_extract(ebits + 1, 0, res_sig_shift_amount));
      m_simp.mk_ite(shift_cond, res_sig, res_sig_shifted, res_sig);
      m_simp.mk_ite(shift_cond, res_exp, res_exp_shifted, res_exp);
  
      round(s, rm, res_sgn, res_sig, res_exp, v8);
  
      // And finally, we tie them together.
      mk_ite(c7, v7, v8, result);
      mk_ite(c6, v6, result, result);
      mk_ite(c5, v5, result, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_div", tout << "DIV = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_rem(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_rem(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_rem(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      TRACE("fpa2bv_rem", tout << "X = " << mk_ismt2_pp(x, m) << std::endl;
                          tout << "Y = " << mk_ismt2_pp(y, m) << std::endl;);
  
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(s, nan);
      mk_nzero(s, nzero);
      mk_pzero(s, pzero);
      mk_ninf(s, ninf);
      mk_pinf(s, pinf);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_neg(m), x_is_inf(m);
      expr_ref y_is_nan(m), y_is_zero(m), y_is_pos(m), y_is_neg(m), y_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_neg(x, x_is_neg);
      mk_is_inf(x, x_is_inf);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(y, y_is_zero);
      mk_is_pos(y, y_is_pos);
      mk_is_neg(y, y_is_neg);
      mk_is_inf(y, y_is_inf);
  
      dbg_decouple("fpa2bv_rem_x_is_nan", x_is_nan);
      dbg_decouple("fpa2bv_rem_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_rem_x_is_pos", x_is_pos);
      dbg_decouple("fpa2bv_rem_x_is_inf", x_is_inf);
      dbg_decouple("fpa2bv_rem_y_is_nan", y_is_nan);
      dbg_decouple("fpa2bv_rem_y_is_zero", y_is_zero);
      dbg_decouple("fpa2bv_rem_y_is_pos", y_is_pos);
      dbg_decouple("fpa2bv_rem_y_is_inf", y_is_inf);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m);
  
      // (x is NaN) || (y is NaN) -> NaN
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      v1 = nan;
  
      // (x is +-oo) -> NaN
      c2 = x_is_inf;
      v2 = nan;
  
      // (y is +-oo) -> x
      c3 = y_is_inf;
      v3 = x;
  
      // (y is 0) -> NaN.
      c4 = y_is_zero;
      v4 = nan;
  
      // (x is 0) -> x
      c5 = x_is_zero;
      v5 = pzero;
  
      // exp(x) < exp(y) -> x
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
      expr * x_sgn, *x_sig, *x_exp;
      expr * y_sgn, *y_sig, *y_exp;
      split_fp(x, x_sgn, x_exp, x_sig);
      split_fp(y, y_sgn, y_exp, y_sig);
      expr_ref one_ebits(m), y_exp_m1(m), xe_lt_yem1(m), ye_neq_zero(m);
      one_ebits = m_bv_util.mk_numeral(1, ebits);
      y_exp_m1 = m_bv_util.mk_bv_sub(y_exp, one_ebits);
      BVULT(x_exp, y_exp_m1, xe_lt_yem1);
      ye_neq_zero = m.mk_not(m.mk_eq(y_exp, m_bv_util.mk_numeral(0, ebits)));
      c6 = m.mk_and(ye_neq_zero, xe_lt_yem1);
      v6 = x;
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m);
      expr_ref b_sgn(m), b_sig(m), b_exp(m), b_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
      unpack(y, b_sgn, b_sig, b_exp, b_lz, true);
  
      dbg_decouple("fpa2bv_rem_a_sgn", a_sgn);
      dbg_decouple("fpa2bv_rem_a_sig", a_sig);
      dbg_decouple("fpa2bv_rem_a_exp", a_exp);
      dbg_decouple("fpa2bv_rem_a_lz", a_lz);
      dbg_decouple("fpa2bv_rem_b_sgn", b_sgn);
      dbg_decouple("fpa2bv_rem_b_sig", b_sig);
      dbg_decouple("fpa2bv_rem_b_exp", b_exp);
      dbg_decouple("fpa2bv_rem_b_lz", b_lz);
  
      // else the actual remainder.
      // max. exponent difference is (2^ebits) - 3
      const mpz & two_to_ebits = fu().fm().m_powers2(ebits);
      mpz max_exp_diff;
      m_mpz_manager.sub(two_to_ebits, 3, max_exp_diff);
      SASSERT(m_mpz_manager.is_int64(max_exp_diff));
      SASSERT(m_mpz_manager.get_uint64(max_exp_diff) <= UINT_MAX);
  
      uint64_t max_exp_diff_ui64 = m_mpz_manager.get_uint64(max_exp_diff);
      SASSERT(max_exp_diff_ui64 <= UINT_MAX);
      unsigned max_exp_diff_ui = (unsigned)max_exp_diff_ui64;
      m_mpz_manager.del(max_exp_diff);
  
      expr_ref a_exp_ext(m), b_exp_ext(m);
      a_exp_ext = m_bv_util.mk_sign_extend(2, a_exp);
      b_exp_ext = m_bv_util.mk_sign_extend(2, b_exp);
  
      expr_ref a_lz_ext(m), b_lz_ext(m);
      a_lz_ext = m_bv_util.mk_zero_extend(2, a_lz);
      b_lz_ext = m_bv_util.mk_zero_extend(2, b_lz);
  
      expr_ref exp_diff(m), neg_exp_diff(m), exp_diff_is_neg(m);
      exp_diff = m_bv_util.mk_bv_sub(
          m_bv_util.mk_bv_sub(a_exp_ext, a_lz_ext),
          m_bv_util.mk_bv_sub(b_exp_ext, b_lz_ext));
      neg_exp_diff = m_bv_util.mk_bv_neg(exp_diff);
      exp_diff_is_neg = m_bv_util.mk_sle(exp_diff, m_bv_util.mk_numeral(0, ebits+2));
      dbg_decouple("fpa2bv_rem_exp_diff", exp_diff);
  
      // CMW: This creates _huge_ bit-vectors, which is potentially sub-optimal,
      // but calculating this via rem = x - y * nearest(x/y) creates huge
      // circuits, too. Lazy instantiation seems the way to go in the long run
      // (using the lazy bit-blaster helps on simple instances).
      expr_ref a_sig_ext(m), b_sig_ext(m), lshift(m), rshift(m), shifted(m), huge_rem(m);
      a_sig_ext = m_bv_util.mk_concat(m_bv_util.mk_zero_extend(max_exp_diff_ui, a_sig), m_bv_util.mk_numeral(0, 3));
      b_sig_ext = m_bv_util.mk_concat(m_bv_util.mk_zero_extend(max_exp_diff_ui, b_sig), m_bv_util.mk_numeral(0, 3));
      lshift = m_bv_util.mk_zero_extend(max_exp_diff_ui + sbits - (ebits+2) + 3, exp_diff);
      rshift = m_bv_util.mk_zero_extend(max_exp_diff_ui + sbits - (ebits+2) + 3, neg_exp_diff);
      shifted = m.mk_ite(exp_diff_is_neg, m_bv_util.mk_bv_ashr(a_sig_ext, rshift),
                                          m_bv_util.mk_bv_shl(a_sig_ext, lshift));
      huge_rem = m_bv_util.mk_bv_urem(shifted, b_sig_ext);
      dbg_decouple("fpa2bv_rem_huge_rem", huge_rem);
  
      expr_ref rndd_sgn(m), rndd_exp(m), rndd_sig(m), rne_bv(m), rndd(m);
      rndd_sgn = a_sgn;
      rndd_exp = m_bv_util.mk_bv_sub(b_exp_ext, b_lz_ext);
      rndd_sig = m_bv_util.mk_extract(sbits+3, 0, huge_rem);
      rne_bv = m_bv_util.mk_numeral(BV_RM_TIES_TO_EVEN, 3);
      round(s, rne_bv, rndd_sgn, rndd_sig, rndd_exp, rndd);
  
      expr_ref y_half(m), ny_half(m), zero_e(m), two_e(m);
      expr_ref y_half_is_zero(m), y_half_is_nz(m);
      expr_ref r_ge_y_half(m), r_gt_ny_half(m), r_le_y_half(m), r_lt_ny_half(m);
      expr_ref r_ge_zero(m), r_le_zero(m);
      expr_ref rounded_sub_y(m), rounded_add_y(m);
      mpf zero, two;
      m_mpf_manager.set(two, ebits, sbits, 2);
      m_mpf_manager.set(zero, ebits, sbits, 0);
      mk_numeral(s, two, two_e);
      mk_numeral(s, zero, zero_e);
      mk_div(s, rne_bv, y, two_e, y_half);
      mk_neg(s, y_half, ny_half);
      mk_is_zero(y_half, y_half_is_zero);
      y_half_is_nz = m.mk_not(y_half_is_zero);
  
      mk_float_ge(s, rndd, y_half, r_ge_y_half);
      mk_float_gt(s, rndd, ny_half, r_gt_ny_half);
      mk_float_le(s, rndd, y_half, r_le_y_half);
      mk_float_lt(s, rndd, ny_half, r_lt_ny_half);
  
      mk_sub(s, rne_bv, rndd, y, rounded_sub_y);
      mk_add(s, rne_bv, rndd, y, rounded_add_y);
  
      expr_ref sub_cnd(m), add_cnd(m);
      sub_cnd = m.mk_and(y_half_is_nz,
                  m.mk_or(m.mk_and(y_is_pos, r_ge_y_half),
                          m.mk_and(y_is_neg, r_le_y_half)));
      add_cnd = m.mk_and(y_half_is_nz,
                  m.mk_or(m.mk_and(y_is_pos, r_lt_ny_half),
                      m.mk_and(y_is_neg, r_gt_ny_half)));
  
      mk_ite(add_cnd, rounded_add_y, rndd, v7);
      mk_ite(sub_cnd, rounded_sub_y, v7, v7);
  
      // And finally, we tie them together.
      mk_ite(c6, v6, v7, result);
      mk_ite(c5, v5, result, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      expr_ref result_is_zero(m), zeros(m);
      mk_is_zero(result, result_is_zero);
      mk_ite(x_is_pos, pzero, nzero, zeros);
      mk_ite(result_is_zero, zeros, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_rem", tout << "REM = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_abs(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref x(m);
      x = args[0];
      mk_abs(f->get_range(), x, result);
  }
  
  void fpa2bv_converter::mk_abs(sort * s, expr_ref & x, expr_ref & result) {
      expr * sgn, *sig, *exp;
      split_fp(x, sgn, exp, sig);
      result = m_util.mk_fp(m_bv_util.mk_numeral(0, 1), exp, sig);
  }
  
  void fpa2bv_converter::mk_min(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
  
      expr * x = args[0], * y = args[1];
  
      expr * x_sgn, *x_sig, *x_exp;
      expr * y_sgn, *y_sig, *y_exp;
      split_fp(x, x_sgn, x_exp, x_sig);
      split_fp(y, y_sgn, y_exp, y_sig);
  
      expr_ref bv0(m), bv1(m);
      bv0 = m_bv_util.mk_numeral(0, 1);
      bv1 = m_bv_util.mk_numeral(1, 1);
  
      expr_ref x_is_nan(m), y_is_nan(m), x_is_zero(m), y_is_zero(m), xy_are_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_zero(y, y_is_zero);
      xy_are_zero = m.mk_and(x_is_zero, y_is_zero);
  
      expr_ref x_is_pos(m), x_is_neg(m);
      expr_ref y_is_pos(m), y_is_neg(m);
      expr_ref pn(m), np(m), pn_or_np_zeros(m);
      mk_is_pos(x, x_is_pos);
      mk_is_pos(y, y_is_pos);
      mk_is_neg(x, x_is_neg);
      mk_is_neg(y, y_is_neg);
      pn_or_np_zeros = m.mk_and(xy_are_zero, m.mk_not(m.mk_eq(x_sgn, y_sgn)));
  
      expr_ref unspec(m);
      unspec = mk_min_max_unspecified(f, x, y);
  
      expr_ref x_lt_y(m);
      mk_float_lt(f, num, args, x_lt_y);
  
      mk_ite(x_lt_y, x, y, result);
      mk_ite(xy_are_zero, y, result, result);
      mk_ite(pn_or_np_zeros, unspec, result, result);
      mk_ite(y_is_nan, x, result, result);
      mk_ite(x_is_nan, y, result, result);
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_max(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
  
      expr * x = args[0], *y = args[1];
  
      expr * x_sgn, *x_sig, *x_exp;
      expr * y_sgn, *y_sig, *y_exp;
      split_fp(x, x_sgn, x_exp, x_sig);
      split_fp(y, y_sgn, y_exp, y_sig);
  
      expr_ref x_is_nan(m), y_is_nan(m), x_is_zero(m), y_is_zero(m), xy_are_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_zero(y, y_is_zero);
      xy_are_zero = m.mk_and(x_is_zero, y_is_zero);
  
      expr_ref x_is_pos(m), x_is_neg(m);
      expr_ref y_is_pos(m), y_is_neg(m);
      expr_ref pn(m), np(m), pn_or_np_zeros(m);
      mk_is_pos(x, x_is_pos);
      mk_is_pos(y, y_is_pos);
      mk_is_neg(x, x_is_neg);
      mk_is_neg(y, y_is_neg);
      pn_or_np_zeros = m.mk_and(xy_are_zero, m.mk_not(m.mk_eq(x_sgn, y_sgn)));
  
      expr_ref unspec(m);
      unspec = mk_min_max_unspecified(f, x, y);
  
      expr_ref x_gt_y(m);
      mk_float_gt(f, num, args, x_gt_y);
  
      mk_ite(x_gt_y, x, y, result);
      mk_ite(xy_are_zero, y, result, result);
      mk_ite(pn_or_np_zeros, unspec, result, result);
      mk_ite(y_is_nan, x, result, result);
      mk_ite(x_is_nan, y, result, result);
  
      SASSERT(is_well_sorted(m, result));
  }
  
  expr_ref fpa2bv_converter::mk_min_max_unspecified(func_decl * f, expr * x, expr * y) {
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
      expr_ref res(m);
  
      // The only cases in which min/max is unspecified for is when the arguments are +0.0 and -0.0.
      // There is no "hardware interpretation" for fp.min/fp.max.
  
      std::pair<app*, app*> decls(0, 0);
      if (!m_min_max_ufs.find(f, decls)) {
          decls.first = m.mk_fresh_const(nullptr, m_bv_util.mk_sort(1));
          decls.second = m.mk_fresh_const(nullptr, m_bv_util.mk_sort(1));
          m_min_max_ufs.insert(f, decls);
          m.inc_ref(f);
          m.inc_ref(decls.first);
          m.inc_ref(decls.second);
      }
  
      expr_ref pn(m), np(m);
      pn = m_util.mk_fp(decls.first, m_bv_util.mk_numeral(0, ebits), m_bv_util.mk_numeral(0, sbits - 1));
      np = m_util.mk_fp(decls.second, m_bv_util.mk_numeral(0, ebits), m_bv_util.mk_numeral(0, sbits - 1));
  
      expr_ref x_is_pzero(m), y_is_nzero(m), xyzero(m);
      mk_is_pzero(x, x_is_pzero);
      mk_is_nzero(y, y_is_nzero);
      m_simp.mk_and(x_is_pzero, y_is_nzero, xyzero);
      mk_ite(xyzero, pn, np, res);
  
      return res;
  }
  
  void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 4);
      SASSERT(m_util.is_bv2rm(args[0]));
  
      // fusedma means (x * y) + z
      expr_ref rm(m), x(m), y(m), z(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
      y = args[2];
      z = args[3];
  
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(f, nan);
      mk_nzero(f, nzero);
      mk_pzero(f, pzero);
      mk_ninf(f, ninf);
      mk_pinf(f, pinf);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_neg(m), x_is_inf(m);
      expr_ref y_is_nan(m), y_is_zero(m), y_is_pos(m), y_is_neg(m), y_is_inf(m);
      expr_ref z_is_nan(m), z_is_zero(m), z_is_pos(m), z_is_neg(m), z_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_neg(x, x_is_neg);
      mk_is_inf(x, x_is_inf);
      mk_is_nan(y, y_is_nan);
      mk_is_zero(y, y_is_zero);
      mk_is_pos(y, y_is_pos);
      mk_is_neg(y, y_is_neg);
      mk_is_inf(y, y_is_inf);
      mk_is_nan(z, z_is_nan);
      mk_is_zero(z, z_is_zero);
      mk_is_pos(z, z_is_pos);
      mk_is_neg(z, z_is_neg);
      mk_is_inf(z, z_is_inf);
  
      expr_ref rm_is_to_neg(m);
      mk_is_rm(rm, BV_RM_TO_NEGATIVE, rm_is_to_neg);
  
      dbg_decouple("fpa2bv_fma_x_is_nan", x_is_nan);
      dbg_decouple("fpa2bv_fma_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_fma_x_is_pos", x_is_pos);
      dbg_decouple("fpa2bv_fma_x_is_inf", x_is_inf);
      dbg_decouple("fpa2bv_fma_y_is_nan", y_is_nan);
      dbg_decouple("fpa2bv_fma_y_is_zero", y_is_zero);
      dbg_decouple("fpa2bv_fma_y_is_pos", y_is_pos);
      dbg_decouple("fpa2bv_fma_y_is_inf", y_is_inf);
      dbg_decouple("fpa2bv_fma_z_is_nan", z_is_nan);
      dbg_decouple("fpa2bv_fma_z_is_zero", z_is_zero);
      dbg_decouple("fpa2bv_fma_z_is_pos", z_is_pos);
      dbg_decouple("fpa2bv_fma_z_is_inf", z_is_inf);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m), c7(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m), v8(m);
  
      expr_ref inf_xor(m), inf_cond(m);
      m_simp.mk_xor(x_is_neg, y_is_neg, inf_xor);
      m_simp.mk_xor(inf_xor, z_is_neg, inf_xor);
      m_simp.mk_and(z_is_inf, inf_xor, inf_cond);
  
      // (x is NaN) || (y is NaN) || (z is Nan) -> NaN
      m_simp.mk_or(x_is_nan, y_is_nan, z_is_nan, c1);
      v1 = nan;
  
      // (x is +oo) -> if (y is 0) then NaN else inf with y's sign.
      mk_is_pinf(x, c2);
      expr_ref y_sgn_inf(m), inf_or(m);
      mk_ite(y_is_pos, pinf, ninf, y_sgn_inf);
      m_simp.mk_or(y_is_zero, inf_cond, inf_or);
      mk_ite(inf_or, nan, y_sgn_inf, v2);
  
      // (y is +oo) -> if (x is 0) then NaN else inf with x's sign.
      mk_is_pinf(y, c3);
      expr_ref x_sgn_inf(m);
      mk_ite(x_is_pos, pinf, ninf, x_sgn_inf);
      m_simp.mk_or(x_is_zero, inf_cond, inf_or);
      mk_ite(inf_or, nan, x_sgn_inf, v3);
  
      // (x is -oo) -> if (y is 0) then NaN else inf with -y's sign.
      mk_is_ninf(x, c4);
      expr_ref neg_y_sgn_inf(m);
      mk_ite(y_is_pos, ninf, pinf, neg_y_sgn_inf);
      m_simp.mk_or(y_is_zero, inf_cond, inf_or);
      mk_ite(inf_or, nan, neg_y_sgn_inf, v4);
  
      // (y is -oo) -> if (x is 0) then NaN else inf with -x's sign.
      mk_is_ninf(y, c5);
      expr_ref neg_x_sgn_inf(m);
      mk_ite(x_is_pos, ninf, pinf, neg_x_sgn_inf);
      m_simp.mk_or(x_is_zero, inf_cond, inf_or);
      mk_ite(inf_or, nan, neg_x_sgn_inf, v5);
  
      // z is +-INF -> z.
      mk_is_inf(z, c6);
      v6 = z;
  
      // (x is 0) || (y is 0) -> z
      expr_ref c71(m), xy_sgn(m), xyz_sgn(m);
      m_simp.mk_or(x_is_zero, y_is_zero, c7);
      m_simp.mk_xor(x_is_neg, y_is_neg, xy_sgn);
  
      m_simp.mk_xor(xy_sgn, z_is_neg, xyz_sgn);
      m_simp.mk_and(z_is_zero, xyz_sgn, c71);
  
      expr_ref zero_cond(m), rm_is_not_to_neg(m);
      rm_is_not_to_neg = m.mk_not(rm_is_to_neg);
      m_simp.mk_ite(rm_is_to_neg, nzero, pzero, zero_cond);
      mk_ite(c71, zero_cond, z, v7);
  
      // else comes the fused multiplication.
      expr_ref one_1(m), zero_1(m);
      one_1 = m_bv_util.mk_numeral(1, 1);
      zero_1 = m_bv_util.mk_numeral(0, 1);
  
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m);
      expr_ref b_sgn(m), b_sig(m), b_exp(m), b_lz(m);
      expr_ref c_sgn(m), c_sig(m), c_exp(m), c_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
      unpack(y, b_sgn, b_sig, b_exp, b_lz, true);
      unpack(z, c_sgn, c_sig, c_exp, c_lz, true);
  
      expr_ref a_lz_ext(m), b_lz_ext(m), c_lz_ext(m);
      a_lz_ext = m_bv_util.mk_zero_extend(2, a_lz);
      b_lz_ext = m_bv_util.mk_zero_extend(2, b_lz);
      c_lz_ext = m_bv_util.mk_zero_extend(2, c_lz);
  
      expr_ref a_sig_ext(m), b_sig_ext(m);
      a_sig_ext = m_bv_util.mk_zero_extend(sbits, a_sig);
      b_sig_ext = m_bv_util.mk_zero_extend(sbits, b_sig);
  
      expr_ref a_exp_ext(m), b_exp_ext(m), c_exp_ext(m);
      a_exp_ext = m_bv_util.mk_sign_extend(2, a_exp);
      b_exp_ext = m_bv_util.mk_sign_extend(2, b_exp);
      c_exp_ext = m_bv_util.mk_sign_extend(2, c_exp);
  
      dbg_decouple("fpa2bv_fma_a_sig", a_sig_ext);
      dbg_decouple("fpa2bv_fma_b_sig", b_sig_ext);
      dbg_decouple("fpa2bv_fma_c_sig", c_sig);
      dbg_decouple("fpa2bv_fma_a_exp", a_exp_ext);
      dbg_decouple("fpa2bv_fma_b_exp", b_exp_ext);
      dbg_decouple("fpa2bv_fma_c_exp", c_exp_ext);
      dbg_decouple("fpa2bv_fma_a_lz", a_lz_ext);
      dbg_decouple("fpa2bv_fma_b_lz", b_lz_ext);
      dbg_decouple("fpa2bv_fma_c_lz", c_lz_ext);
  
      expr_ref mul_sgn(m), mul_sig(m), mul_exp(m);
      expr * signs[2] = { a_sgn, b_sgn };
  
      mul_sgn = m_bv_util.mk_bv_xor(2, signs);
      dbg_decouple("fpa2bv_fma_mul_sgn", mul_sgn);
  
      mul_exp = m_bv_util.mk_bv_add(
          m_bv_util.mk_bv_sub(a_exp_ext, a_lz_ext),
          m_bv_util.mk_bv_sub(b_exp_ext, b_lz_ext));
      dbg_decouple("fpa2bv_fma_mul_exp", mul_exp);
  
      mul_sig = m_bv_util.mk_bv_mul(a_sig_ext, b_sig_ext);
      dbg_decouple("fpa2bv_fma_mul_sig", mul_sig);
  
      SASSERT(m_bv_util.get_bv_size(mul_sig) == 2*sbits);
      SASSERT(m_bv_util.get_bv_size(mul_exp) == ebits + 2);
  
      // The product has the form [-1][0].[2*sbits - 2].
  
      // Extend c
      expr_ref c_sig_ext(m);
      c_sig_ext = m_bv_util.mk_zero_extend(1, m_bv_util.mk_concat(c_sig, m_bv_util.mk_numeral(0, sbits+2)));
      c_exp_ext = m_bv_util.mk_bv_sub(c_exp_ext, c_lz_ext);
      mul_sig = m_bv_util.mk_concat(mul_sig, m_bv_util.mk_numeral(0, 3));
  
      SASSERT(m_bv_util.get_bv_size(mul_sig) == 2*sbits+3);
      SASSERT(m_bv_util.get_bv_size(c_sig_ext) == 2*sbits+3);
      dbg_decouple("fpa2bv_fma_c_sig_ext", c_sig_ext);
      dbg_decouple("fpa2bv_fma_c_exp_ext", c_exp_ext);
  
      expr_ref swap_cond(m);
      swap_cond = m_bv_util.mk_sle(mul_exp, c_exp_ext);
      SASSERT(is_well_sorted(m, swap_cond));
      dbg_decouple("fpa2bv_fma_swap_cond", swap_cond);
  
      expr_ref e_sgn(m), e_sig(m), e_exp(m), f_sgn(m), f_sig(m), f_exp(m);
      m_simp.mk_ite(swap_cond, c_sgn, mul_sgn, e_sgn);
      m_simp.mk_ite(swap_cond, c_sig_ext, mul_sig, e_sig); // has 2 * sbits + 3
      m_simp.mk_ite(swap_cond, c_exp_ext, mul_exp, e_exp); // has ebits + 2
      m_simp.mk_ite(swap_cond, mul_sgn, c_sgn, f_sgn);
      m_simp.mk_ite(swap_cond, mul_sig, c_sig_ext, f_sig); // has 2 * sbits + 3
      m_simp.mk_ite(swap_cond, mul_exp, c_exp_ext, f_exp); // has ebits + 2
  
      SASSERT(is_well_sorted(m, e_sgn));
      SASSERT(is_well_sorted(m, e_sig));
      SASSERT(is_well_sorted(m, e_exp));
      SASSERT(is_well_sorted(m, f_sgn));
      SASSERT(is_well_sorted(m, f_sig));
      SASSERT(is_well_sorted(m, f_exp));
  
      SASSERT(m_bv_util.get_bv_size(e_sig) == 2*sbits+3);
      SASSERT(m_bv_util.get_bv_size(f_sig) == 2*sbits+3);
      SASSERT(m_bv_util.get_bv_size(e_exp) == ebits + 2);
      SASSERT(m_bv_util.get_bv_size(f_exp) == ebits + 2);
  
      dbg_decouple("fpa2bv_fma_e_sig", e_sig);
      dbg_decouple("fpa2bv_fma_e_exp", e_exp);
      dbg_decouple("fpa2bv_fma_f_sig", f_sig);
      dbg_decouple("fpa2bv_fma_f_exp", f_exp);
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
  
      expr_ref exp_delta(m);
      exp_delta = m_bv_util.mk_bv_sub(e_exp, f_exp);
      dbg_decouple("fpa2bv_fma_add_exp_delta", exp_delta);
  
      // cap the delta
      expr_ref cap(m), cap_le_delta(m);
      cap = m_bv_util.mk_numeral(2*sbits+3, ebits+2);
      cap_le_delta = m_bv_util.mk_ule(cap, exp_delta);
      m_simp.mk_ite(cap_le_delta, cap, exp_delta, exp_delta);
      SASSERT(m_bv_util.get_bv_size(exp_delta) == ebits+2);
      SASSERT(is_well_sorted(m, exp_delta));
      dbg_decouple("fpa2bv_fma_add_exp_delta_capped", exp_delta);
  
      // Alignment shift with sticky bit computation.
      expr_ref shifted_big(m), shifted_f_sig(m);
      expr_ref alignment_sticky_raw(m), alignment_sticky(m);
      shifted_big = m_bv_util.mk_bv_lshr(
          m_bv_util.mk_concat(f_sig, m_bv_util.mk_numeral(0, sbits)),
          m_bv_util.mk_zero_extend((3*sbits+3)-(ebits+2), exp_delta));
      shifted_f_sig = m_bv_util.mk_extract(3*sbits+2, sbits, shifted_big);
      alignment_sticky_raw = m_bv_util.mk_extract(sbits-1, 0, shifted_big);
      alignment_sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, alignment_sticky_raw.get());
      dbg_decouple("fpa2bv_fma_shifted_f_sig", shifted_f_sig);
      dbg_decouple("fpa2bv_fma_f_sig_alignment_sticky", alignment_sticky);
      SASSERT(is_well_sorted(m, alignment_sticky));
      SASSERT(m_bv_util.get_bv_size(shifted_f_sig) == 2*sbits+3);
      SASSERT(is_well_sorted(m, shifted_f_sig));
  
      // Significant addition.
      // Two extra bits for the sign and for catching overflows.
      e_sig = m_bv_util.mk_zero_extend(2, e_sig);
      shifted_f_sig = m_bv_util.mk_zero_extend(2, shifted_f_sig);
  
      expr_ref eq_sgn(m);
      m_simp.mk_eq(e_sgn, f_sgn, eq_sgn);
      dbg_decouple("fpa2bv_fma_eq_sgn", eq_sgn);
  
      SASSERT(m_bv_util.get_bv_size(e_sig) == 2*sbits+5);
      SASSERT(m_bv_util.get_bv_size(shifted_f_sig) == 2*sbits+5);
  
      dbg_decouple("fpa2bv_fma_add_e_sig", e_sig);
      dbg_decouple("fpa2bv_fma_add_shifted_f_sig", shifted_f_sig);
  
      expr_ref sum(m), e_plus_f(m), e_minus_f(m), sticky_wide(m);
      sticky_wide = m_bv_util.mk_zero_extend(2*sbits+4, alignment_sticky);
      e_plus_f = m_bv_util.mk_bv_add(e_sig, shifted_f_sig);
      e_plus_f = m.mk_ite(m.mk_eq(m_bv_util.mk_extract(0, 0, e_plus_f), zero_1),
                          m_bv_util.mk_bv_add(e_plus_f, sticky_wide),
                          e_plus_f);
      e_minus_f = m_bv_util.mk_bv_sub(e_sig, shifted_f_sig);
      e_minus_f = m.mk_ite(m.mk_eq(m_bv_util.mk_extract(0, 0, e_minus_f), zero_1),
                           m_bv_util.mk_bv_sub(e_minus_f, sticky_wide),
                           e_minus_f);
      SASSERT(is_well_sorted(m, shifted_f_sig));
      dbg_decouple("fpa2bv_fma_f_sig_or_sticky", shifted_f_sig);
  
      m_simp.mk_ite(eq_sgn, e_plus_f, e_minus_f, sum);
      SASSERT(m_bv_util.get_bv_size(sum) == 2*sbits+5);
      SASSERT(is_well_sorted(m, sum));
      dbg_decouple("fpa2bv_fma_add_sum", sum);
  
      expr_ref sign_bv(m), n_sum(m);
      sign_bv = m_bv_util.mk_extract(2*sbits+4, 2*sbits+4, sum);
      n_sum = m_bv_util.mk_bv_neg(sum);
      dbg_decouple("fpa2bv_fma_add_sign_bv", sign_bv);
      dbg_decouple("fpa2bv_fma_add_n_sum", n_sum);
  
      expr_ref res_sig_eq(m), sig_abs(m);
      m_simp.mk_eq(sign_bv, one_1, res_sig_eq);
      m_simp.mk_ite(res_sig_eq, n_sum, sum, sig_abs);
      dbg_decouple("fpa2bv_fma_add_sig_abs", sig_abs);
  
      family_id bvfid = m_bv_util.get_fid();
      expr_ref res_sgn_c1(m), res_sgn_c2(m), res_sgn_c3(m);
      expr_ref not_e_sgn(m), not_f_sgn(m), not_sign_bv(m);
      not_e_sgn = m_bv_util.mk_bv_not(e_sgn);
      not_f_sgn = m_bv_util.mk_bv_not(f_sgn);
      not_sign_bv = m_bv_util.mk_bv_not(sign_bv);
      res_sgn_c1 = m.mk_app(bvfid, OP_BAND, not_e_sgn, f_sgn, sign_bv);
      res_sgn_c2 = m.mk_app(bvfid, OP_BAND, e_sgn, not_f_sgn, not_sign_bv);
      res_sgn_c3 = m.mk_app(bvfid, OP_BAND, e_sgn, f_sgn);
      expr * res_sgn_or_args[3] = { res_sgn_c1, res_sgn_c2, res_sgn_c3 };
      res_sgn = m_bv_util.mk_bv_or(3, res_sgn_or_args);
      dbg_decouple("fpa2bv_fma_res_sgn", res_sgn);
  
      expr_ref is_sig_neg(m);
      is_sig_neg = m.mk_eq(one_1, m_bv_util.mk_extract(2*sbits+4, 2*sbits+4, sig_abs));
      sig_abs = m.mk_ite(is_sig_neg, m_bv_util.mk_bv_neg(sig_abs), sig_abs);
      dbg_decouple("fpa2bv_fma_is_sig_neg", is_sig_neg);
  
      // Result could have overflown into 4.xxx.
      SASSERT(m_bv_util.get_bv_size(sig_abs) == 2*sbits+5);
      expr_ref extra(m), extra_is_zero(m);
      extra = m_bv_util.mk_extract(2*sbits+4, 2*sbits+3, sig_abs);
      extra_is_zero = m.mk_eq(extra, m_bv_util.mk_numeral(0, 2));
      dbg_decouple("fpa2bv_fma_extra", extra);
  
      res_exp = m.mk_ite(extra_is_zero, e_exp, m_bv_util.mk_bv_add(e_exp, m_bv_util.mk_numeral(1, ebits + 2)));
  
      // Renormalize
      expr_ref zero_e2(m), min_exp(m), sig_lz(m), max_exp_delta(m), sig_lz_capped(m), renorm_delta(m);
      zero_e2 = m_bv_util.mk_numeral(0, ebits + 2);
      mk_min_exp(ebits, min_exp);
      min_exp = m_bv_util.mk_sign_extend(2, min_exp);
      mk_leading_zeros(sig_abs, ebits+2, sig_lz);
      sig_lz = m_bv_util.mk_bv_sub(sig_lz, m_bv_util.mk_numeral(2, ebits+2));
      max_exp_delta = m_bv_util.mk_bv_sub(res_exp, min_exp);
      sig_lz_capped = m.mk_ite(m_bv_util.mk_sle(sig_lz, max_exp_delta), sig_lz, max_exp_delta);
      renorm_delta = m.mk_ite(m_bv_util.mk_sle(zero_e2, sig_lz_capped), sig_lz_capped, zero_e2);
      res_exp = m_bv_util.mk_bv_sub(res_exp, renorm_delta);
      sig_abs = m_bv_util.mk_bv_shl(sig_abs, m_bv_util.mk_zero_extend(2*sbits+3-ebits, renorm_delta));
      dbg_decouple("fpa2bv_fma_min_exp", min_exp);
      dbg_decouple("fpa2bv_fma_max_exp_delta", max_exp_delta);
      dbg_decouple("fpa2bv_fma_sig_lz", sig_lz);
      dbg_decouple("fpa2bv_fma_sig_lz_capped", sig_lz_capped);
      dbg_decouple("fpa2bv_fma_renorm_delta", renorm_delta);
  
      unsigned too_short = 0;
      if (sbits < 5) {
          too_short = 6 - sbits + 1;
          sig_abs = m_bv_util.mk_concat(sig_abs, m_bv_util.mk_numeral(0, too_short));
      }
  
      expr_ref sig_abs_h1(m), sticky_h1(m), sticky_h1_red(m), sig_abs_h1_f(m), res_sig_1(m);
      sticky_h1 = m_bv_util.mk_extract(sbits+too_short-2, 0, sig_abs);
      sig_abs_h1 = m_bv_util.mk_extract(2*sbits+too_short+4, sbits-1+too_short, sig_abs);
      sticky_h1_red = m_bv_util.mk_zero_extend(sbits+5, m.mk_app(m_bv_util.get_fid(), OP_BREDOR, sticky_h1.get()));
      expr * sticky_h1_red_args[2] = { sig_abs_h1, sticky_h1_red };
      sig_abs_h1_f = m_bv_util.mk_bv_or(2, sticky_h1_red_args);
      res_sig_1 = m_bv_util.mk_extract(sbits+3, 0, sig_abs_h1_f);
      SASSERT(m_bv_util.get_bv_size(sticky_h1) == sbits+too_short-1);
      SASSERT(m_bv_util.get_bv_size(sig_abs_h1) == sbits+6);
      SASSERT(m_bv_util.get_bv_size(sticky_h1_red) == sbits+6);
      SASSERT(m_bv_util.get_bv_size(sig_abs_h1_f) == sbits+6);
      SASSERT(m_bv_util.get_bv_size(res_sig_1) == sbits+4);
  
      expr_ref sig_abs_h2(m), sticky_h2(m), sticky_h2_red(m), sig_abs_h2_f(m), res_sig_2(m);
      sticky_h2 = m_bv_util.mk_extract(sbits+too_short-1, 0, sig_abs);
      sig_abs_h2 = m_bv_util.mk_extract(2*sbits+too_short+4, sbits+too_short, sig_abs);
      sticky_h2_red = m_bv_util.mk_zero_extend(sbits+4, m.mk_app(m_bv_util.get_fid(), OP_BREDOR, sticky_h1.get()));
      expr * sticky_h2_red_args[2] = { sig_abs_h2, sticky_h2_red };
      sig_abs_h2_f = m_bv_util.mk_zero_extend(1, m_bv_util.mk_bv_or(2, sticky_h2_red_args));
      res_sig_2 = m_bv_util.mk_extract(sbits+3, 0, sig_abs_h2_f);
      SASSERT(m_bv_util.get_bv_size(sticky_h2) == sbits+too_short);
      SASSERT(m_bv_util.get_bv_size(sig_abs_h2) == sbits+5);
      SASSERT(m_bv_util.get_bv_size(sticky_h2_red) == sbits+5);
      SASSERT(m_bv_util.get_bv_size(sig_abs_h2_f) == sbits+6);
      SASSERT(m_bv_util.get_bv_size(res_sig_2) == sbits+4);
  
      res_sig = m.mk_ite(extra_is_zero, res_sig_1, res_sig_2);
  
      dbg_decouple("fpa2bv_fma_res_sig", res_sig);
      dbg_decouple("fpa2bv_fma_res_exp", res_exp);
      SASSERT(m_bv_util.get_bv_size(res_sig) == sbits + 4);
  
      expr_ref is_zero_sig(m), nil_sbits4(m);
      nil_sbits4 = m_bv_util.mk_numeral(0, sbits+4);
      m_simp.mk_eq(res_sig, nil_sbits4, is_zero_sig);
      SASSERT(is_well_sorted(m, is_zero_sig));
  
      dbg_decouple("fpa2bv_fma_is_zero_sig", is_zero_sig);
  
      expr_ref zero_case(m);
      mk_ite(rm_is_to_neg, nzero, pzero, zero_case);
  
      expr_ref rounded(m);
      round(f->get_range(), rm, res_sgn, res_sig, res_exp, rounded);
  
      mk_ite(is_zero_sig, zero_case, rounded, v8);
  
      // And finally, we tie them together.
      mk_ite(c7, v7, v8, result);
      mk_ite(c6, v6, result, result);
      mk_ite(c5, v5, result, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_fma_", tout << "FMA = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_sqrt(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      SASSERT(m_util.is_bv2rm(args[0]));
  
      expr_ref rm(m), x(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
  
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(f, nan);
      mk_nzero(f, nzero);
      mk_pzero(f, pzero);
      mk_ninf(f, ninf);
      mk_pinf(f, pinf);
  
      expr_ref x_is_nan(m), x_is_zero(m), x_is_pos(m), x_is_inf(m);
      mk_is_nan(x, x_is_nan);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_inf(x, x_is_inf);
  
      expr_ref zero1(m), one1(m);
      zero1 = m_bv_util.mk_numeral(0, 1);
      one1 = m_bv_util.mk_numeral(1, 1);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m), c6(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m), v7(m);
  
      // (x is NaN) -> NaN
      c1 = x_is_nan;
      v1 = x;
  
      // (x is +oo) -> +oo
      mk_is_pinf(x, c2);
      v2 = x;
  
      // (x is +-0) -> +-0
      mk_is_zero(x, c3);
      v3 = x;
  
      // (x < 0) -> NaN
      mk_is_neg(x, c4);
      v4 = nan;
  
      // else comes the actual square root.
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
  
      dbg_decouple("fpa2bv_sqrt_sig", a_sig);
      dbg_decouple("fpa2bv_sqrt_exp", a_exp);
  
      SASSERT(m_bv_util.get_bv_size(a_sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(a_exp) == ebits);
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
  
      res_sgn = zero1;
  
      expr_ref real_exp(m);
      real_exp = m_bv_util.mk_bv_sub(m_bv_util.mk_sign_extend(1, a_exp), m_bv_util.mk_zero_extend(1, a_lz));
      res_exp = m_bv_util.mk_sign_extend(2, m_bv_util.mk_extract(ebits, 1, real_exp));
  
      expr_ref e_is_odd(m);
      e_is_odd = m.mk_eq(m_bv_util.mk_extract(0, 0, real_exp), one1);
  
      dbg_decouple("fpa2bv_sqrt_e_is_odd", e_is_odd);
      dbg_decouple("fpa2bv_sqrt_real_exp", real_exp);
  
      expr_ref sig_prime(m), a_z(m), z_a(m);
      a_z = m_bv_util.mk_concat(a_sig, zero1);
      z_a = m_bv_util.mk_concat(zero1, a_sig);
      m_simp.mk_ite(e_is_odd, a_z, z_a, sig_prime);
      SASSERT(m_bv_util.get_bv_size(sig_prime) == sbits+1);
      dbg_decouple("fpa2bv_sqrt_sig_prime", sig_prime);
  
      // This is algorithm 10.2 in the Handbook of Floating-Point Arithmetic
      expr_ref Q(m), R(m), S(m), T(m);
  
      const mpz & p2 = fu().fm().m_powers2(sbits+3);
      Q = m_bv_util.mk_numeral(p2, sbits+5);
      R = m_bv_util.mk_bv_sub(m_bv_util.mk_concat(sig_prime, m_bv_util.mk_numeral(0, 4)), Q);
      S = Q;
  
      for (unsigned i = 0; i < sbits + 3; i++) {
          dbg_decouple("fpa2bv_sqrt_Q", Q);
          dbg_decouple("fpa2bv_sqrt_R", R);
  
          S = m_bv_util.mk_concat(zero1, m_bv_util.mk_extract(sbits+4, 1, S));
  
          expr_ref twoQ_plus_S(m);
          twoQ_plus_S = m_bv_util.mk_bv_add(m_bv_util.mk_concat(Q, zero1), m_bv_util.mk_concat(zero1, S));
          T = m_bv_util.mk_bv_sub(m_bv_util.mk_concat(R, zero1), twoQ_plus_S);
  
          dbg_decouple("fpa2bv_sqrt_T", T);
  
          SASSERT(m_bv_util.get_bv_size(Q) == sbits + 5);
          SASSERT(m_bv_util.get_bv_size(R) == sbits + 5);
          SASSERT(m_bv_util.get_bv_size(S) == sbits + 5);
          SASSERT(m_bv_util.get_bv_size(T) == sbits + 6);
  
          expr_ref t_lt_0(m), T_lsds5(m);
          T_lsds5 = m_bv_util.mk_extract(sbits + 5, sbits + 5, T);
          m_simp.mk_eq(T_lsds5, one1, t_lt_0);
  
          expr * or_args[2] = { Q, S };
          expr_ref Q_or_S(m), R_shftd(m), T_lsds4(m);
          Q_or_S = m_bv_util.mk_bv_or(2, or_args);
          m_simp.mk_ite(t_lt_0, Q, Q_or_S, Q);
          R_shftd = m_bv_util.mk_concat(m_bv_util.mk_extract(sbits + 3, 0, R), zero1);
          T_lsds4 = m_bv_util.mk_extract(sbits + 4, 0, T);
          m_simp.mk_ite(t_lt_0, R_shftd, T_lsds4, R);
      }
  
      expr_ref is_exact(m), zero_sbits5(m);
      zero_sbits5 = m_bv_util.mk_numeral(0, sbits + 5);
      m_simp.mk_eq(R, zero_sbits5, is_exact);
      dbg_decouple("fpa2bv_sqrt_is_exact", is_exact);
  
      expr_ref rest(m), last(m), q_is_odd(m), rest_ext(m);
      last = m_bv_util.mk_extract(0, 0, Q);
      rest = m_bv_util.mk_extract(sbits+3, 1, Q);
      dbg_decouple("fpa2bv_sqrt_last", last);
      dbg_decouple("fpa2bv_sqrt_rest", rest);
      rest_ext = m_bv_util.mk_zero_extend(1, rest);
      expr_ref sticky(m), last_ext(m), one_sbits4(m);
      last_ext = m_bv_util.mk_zero_extend(sbits + 3, last);
      one_sbits4 = m_bv_util.mk_numeral(1, sbits + 4);
      m_simp.mk_ite(is_exact, last_ext, one_sbits4, sticky);
      expr * or_args[2] = { rest_ext, sticky };
      res_sig = m_bv_util.mk_bv_or(2, or_args);
  
      SASSERT(m_bv_util.get_bv_size(res_sig) == sbits + 4);
  
      expr_ref rounded(m);
      round(f->get_range(), rm, res_sgn, res_sig, res_exp, rounded);
      v5 = rounded;
  
      // And finally, we tie them together.
      mk_ite(c4, v4, v5, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_round_to_integral(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      SASSERT(m_util.is_bv2rm(args[0]));
  
      expr_ref rm(m), x(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
      mk_round_to_integral(f->get_range(), rm, x, result);
  }
  
  void fpa2bv_converter::mk_round_to_integral(sort * s, expr_ref & rm, expr_ref & x, expr_ref & result) {
      expr_ref rm_is_rta(m), rm_is_rte(m), rm_is_rtp(m), rm_is_rtn(m), rm_is_rtz(m);
      mk_is_rm(rm, BV_RM_TIES_TO_AWAY, rm_is_rta);
      mk_is_rm(rm, BV_RM_TIES_TO_EVEN, rm_is_rte);
      mk_is_rm(rm, BV_RM_TO_POSITIVE, rm_is_rtp);
      mk_is_rm(rm, BV_RM_TO_NEGATIVE, rm_is_rtn);
      mk_is_rm(rm, BV_RM_TO_ZERO, rm_is_rtz);
  
      expr_ref nan(m), nzero(m), pzero(m), ninf(m), pinf(m);
      mk_nan(s, nan);
      mk_nzero(s, nzero);
      mk_pzero(s, pzero);
  
      expr_ref x_is_zero(m), x_is_pos(m), x_is_neg(m);
      mk_is_zero(x, x_is_zero);
      mk_is_pos(x, x_is_pos);
      mk_is_neg(x, x_is_neg);
  
      dbg_decouple("fpa2bv_r2i_x_is_zero", x_is_zero);
      dbg_decouple("fpa2bv_r2i_x_is_pos", x_is_pos);
  
      expr_ref c1(m), c2(m), c3(m), c4(m), c5(m);
      expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m);
  
      // (x is NaN) -> NaN
      mk_is_nan(x, c1);
      v1 = nan;
  
      // (x is +-oo) -> x
      mk_is_inf(x, c2);
      v2 = x;
  
      // (x is +-0) -> x ; -0.0 -> -0.0, says IEEE754, Sec 5.9.
      mk_is_zero(x, c3);
      v3 = x;
  
  
      expr_ref one_1(m), zero_1(m);
      one_1 = m_bv_util.mk_numeral(1, 1);
      zero_1 = m_bv_util.mk_numeral(0, 1);
  
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
  
      expr_ref a_sgn(m), a_sig(m), a_exp(m), a_lz(m);
      unpack(x, a_sgn, a_sig, a_exp, a_lz, true);
  
      dbg_decouple("fpa2bv_r2i_unpacked_sgn", a_sgn);
      dbg_decouple("fpa2bv_r2i_unpacked_exp", a_exp);
      dbg_decouple("fpa2bv_r2i_unpacked_sig", a_sig);
      dbg_decouple("fpa2bv_r2i_unpacked_lz", a_lz);
  
      expr_ref xzero(m), sgn_eq_1(m);
      sgn_eq_1 = m.mk_eq(a_sgn, one_1);
      mk_ite(sgn_eq_1, nzero, pzero, xzero);
  
      // exponent < 0 -> 0/1
      expr_ref exp_lt_zero(m), exp_h(m);
      exp_h = m_bv_util.mk_extract(ebits-1, ebits-1, a_exp);
      m_simp.mk_eq(exp_h, one_1, exp_lt_zero);
      dbg_decouple("fpa2bv_r2i_exp_lt_zero", exp_lt_zero);
      c4 = exp_lt_zero;
  
      expr_ref pone(m), none(m), xone(m), c421(m), c422(m), c423(m), t1(m), t2(m), tie(m), v42(m), exp_lt_m1(m);
      mk_one(s, zero_1, pone);
      mk_one(s, one_1, none);
      mk_ite(sgn_eq_1, none, pone, xone);
  
      expr_ref pow_2_sbitsm1(m), m1(m);
      pow_2_sbitsm1 = m_bv_util.mk_numeral(fu().fm().m_powers2(sbits - 1), sbits);
      m1 = m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, ebits));
      m_simp.mk_eq(a_sig, pow_2_sbitsm1, t1);
      m_simp.mk_eq(a_exp, m1, t2);
      m_simp.mk_and(t1, t2, tie);
      dbg_decouple("fpa2bv_r2i_c42_tie", tie);
  
      m_simp.mk_and(tie, rm_is_rte, c421);
      m_simp.mk_and(tie, rm_is_rta, c422);
      c423 = m_bv_util.mk_sle(a_exp, m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(2, ebits)));
  
      dbg_decouple("fpa2bv_r2i_c421", c421);
      dbg_decouple("fpa2bv_r2i_c422", c422);
      dbg_decouple("fpa2bv_r2i_c423", c423);
  
      v42 = xone;
      mk_ite(c423, xzero, v42, v42);
      mk_ite(c422, xone, v42, v42);
      mk_ite(c421, xzero, v42, v42);
  
      expr_ref v4_rtn(m), v4_rtp(m);
      mk_ite(x_is_neg, nzero, pone, v4_rtp);
      mk_ite(x_is_neg, none, pzero, v4_rtn);
  
      mk_ite(rm_is_rtp, v4_rtp, v42, v4);
      mk_ite(rm_is_rtn, v4_rtn, v4, v4);
      mk_ite(rm_is_rtz, xzero, v4, v4);
  
      SASSERT(is_well_sorted(m, v4));
  
      // exponent >= sbits-1
      expr_ref exp_is_large(m);
      exp_is_large = m_bv_util.mk_sle(m_bv_util.mk_numeral(sbits-1, ebits), a_exp);
      dbg_decouple("fpa2bv_r2i_exp_is_large", exp_is_large);
      c5 = exp_is_large;
      v5 = x;
  
      // Actual conversion with rounding.
      // x.exponent >= 0 && x.exponent < x.sbits - 1
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
      res_sgn = a_sgn;
      res_exp = a_exp;
  
      SASSERT(m_bv_util.get_bv_size(a_sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(a_exp) == ebits);
  
      expr_ref zero_s(m);
      zero_s = m_bv_util.mk_numeral(0, sbits);
  
      expr_ref shift(m), shifted_sig(m), div(m), rem(m);
      shift = m_bv_util.mk_bv_sub(m_bv_util.mk_numeral(sbits - 1, sbits),
                                  m_bv_util.mk_zero_extend(sbits-ebits, a_exp));
      shifted_sig = m_bv_util.mk_bv_lshr(m_bv_util.mk_concat(a_sig, zero_s),
                                         m_bv_util.mk_concat(zero_s, shift));
      div = m_bv_util.mk_extract(2*sbits-1, sbits, shifted_sig);
      rem = m_bv_util.mk_extract(sbits-1, 0, shifted_sig);
  
      SASSERT(is_well_sorted(m, div));
      SASSERT(is_well_sorted(m, rem));
      SASSERT(m_bv_util.get_bv_size(shift) == sbits);
      SASSERT(m_bv_util.get_bv_size(div) == sbits);
      SASSERT(m_bv_util.get_bv_size(rem) == sbits);
  
      dbg_decouple("fpa2bv_r2i_shifted_sig", shifted_sig);
      dbg_decouple("fpa2bv_r2i_shift", shift);
      dbg_decouple("fpa2bv_r2i_div", div);
      dbg_decouple("fpa2bv_r2i_rem", rem);
  
      expr_ref div_p1(m);
      div_p1 = m_bv_util.mk_bv_add(div, m_bv_util.mk_numeral(1, sbits));
  
      expr_ref tie_pttrn(m), tie2(m), tie2_c(m), div_last(m), v51(m);
      tie_pttrn = m_bv_util.mk_concat(one_1, m_bv_util.mk_numeral(0, sbits-1));
      m_simp.mk_eq(rem, tie_pttrn, tie2);
      div_last = m_bv_util.mk_extract(0, 0, div);
      expr_ref div_last_eq_1(m), rte_and_dl_eq_1(m), rte_and_dl_eq_1_or_rta(m), tie_pttrn_ule_rem(m);
      div_last_eq_1 = m.mk_eq(div_last, one_1);
      rte_and_dl_eq_1 = m.mk_and(rm_is_rte, div_last_eq_1);
      rte_and_dl_eq_1_or_rta = m.mk_or(rte_and_dl_eq_1, rm_is_rta);
      tie_pttrn_ule_rem = m_bv_util.mk_ule(tie_pttrn, rem);
      tie2_c = m.mk_ite(tie2, rte_and_dl_eq_1_or_rta, tie_pttrn_ule_rem);
      m_simp.mk_ite(tie2_c, div_p1, div, v51);
  
      dbg_decouple("fpa2bv_r2i_v51", v51);
      dbg_decouple("fpa2bv_r2i_tie2", tie2);
      dbg_decouple("fpa2bv_r2i_tie2_c", tie2_c);
  
      SASSERT(is_well_sorted(m, tie2));
      SASSERT(is_well_sorted(m, tie2_c));
      SASSERT(is_well_sorted(m, v51));
  
      expr_ref c521(m), v52(m), rem_eq_0(m), sgn_eq_zero(m);
      rem_eq_0 = m.mk_eq(rem, m_bv_util.mk_numeral(0, sbits));
      sgn_eq_zero = m.mk_eq(res_sgn, zero_1);
      m_simp.mk_not(rem_eq_0, c521);
      m_simp.mk_and(c521, sgn_eq_zero, c521);
      m_simp.mk_ite(c521, div_p1, div, v52);
  
      expr_ref c531(m), v53(m), sgn_eq_one(m);
      sgn_eq_one = m.mk_eq(res_sgn, one_1);
      m_simp.mk_not(rem_eq_0, c531);
      m_simp.mk_and(c531, sgn_eq_one, c531);
      m_simp.mk_ite(c531, div_p1, div, v53);
  
      expr_ref c51(m), c52(m), c53(m);
      c51 = m.mk_or(rm_is_rte, rm_is_rta);
      c52 = rm_is_rtp;
      c53 = rm_is_rtn;
  
      res_sig = div;
      m_simp.mk_ite(c53, v53, res_sig, res_sig);
      m_simp.mk_ite(c52, v52, res_sig, res_sig);
      m_simp.mk_ite(c51, v51, res_sig, res_sig);
      res_sig = m_bv_util.mk_zero_extend(1, m_bv_util.mk_concat(res_sig, m_bv_util.mk_numeral(0, 3))); // rounding bits are all 0.
  
      SASSERT(m_bv_util.get_bv_size(res_exp) == ebits);
      SASSERT(m_bv_util.get_bv_size(shift) == sbits);
  
      expr_ref e_shift(m);
      e_shift = (ebits + 2 <= sbits + 1) ? m_bv_util.mk_extract(ebits + 1, 0, shift) :
                                           m_bv_util.mk_sign_extend((ebits + 2) - (sbits), shift);
      SASSERT(m_bv_util.get_bv_size(e_shift) == ebits + 2);
      res_exp = m_bv_util.mk_bv_add(m_bv_util.mk_zero_extend(2, res_exp), e_shift);
  
      SASSERT(m_bv_util.get_bv_size(res_sgn) == 1);
      SASSERT(m_bv_util.get_bv_size(res_sig) == sbits + 4);
      SASSERT(m_bv_util.get_bv_size(res_exp) == ebits + 2);
  
      // CMW: We use the rounder for normalization.
      round(s, rm, res_sgn, res_sig, res_exp, v6);
  
      // And finally, we tie them together.
      mk_ite(c5, v5, v6, result);
      mk_ite(c4, v4, result, result);
      mk_ite(c3, v3, result, result);
      mk_ite(c2, v2, result, result);
      mk_ite(c1, v1, result, result);
  
      SASSERT(is_well_sorted(m, result));
  
      TRACE("fpa2bv_round_to_integral", tout << "ROUND2INTEGRAL = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_float_eq(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_float_eq(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_float_eq(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      TRACE("fpa2bv_float_eq", tout << "X = " << mk_ismt2_pp(x, m) << std::endl;
                               tout << "Y = " << mk_ismt2_pp(y, m) << std::endl;);
  
      expr_ref c1(m), c2(m), x_is_nan(m), y_is_nan(m), x_is_zero(m), y_is_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_nan(y, y_is_nan);
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      mk_is_zero(x, x_is_zero);
      mk_is_zero(y, y_is_zero);
      m_simp.mk_and(x_is_zero, y_is_zero, c2);
  
      expr * x_sgn, * x_sig, * x_exp;
      expr * y_sgn, * y_sig, * y_exp;
      split_fp(x, x_sgn, x_exp, x_sig);
      split_fp(y, y_sgn, y_exp, y_sig);
  
      expr_ref x_eq_y_sgn(m), x_eq_y_exp(m), x_eq_y_sig(m);
      m_simp.mk_eq(x_sgn, y_sgn, x_eq_y_sgn);
      m_simp.mk_eq(x_exp, y_exp, x_eq_y_exp);
      m_simp.mk_eq(x_sig, y_sig, x_eq_y_sig);
  
      expr_ref c3(m), t4(m);
      m_simp.mk_not(x_eq_y_sgn, c3);
      m_simp.mk_and(x_eq_y_exp, x_eq_y_sig, t4);
  
      expr_ref c3t4(m), c2else(m);
      m_simp.mk_ite(c3, m.mk_false(), t4, c3t4);
      m_simp.mk_ite(c2, m.mk_true(), c3t4, c2else);
      m_simp.mk_ite(c1, m.mk_false(), c2else, result);
  
      TRACE("fpa2bv_float_eq", tout << "FLOAT_EQ = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_float_lt(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_float_lt(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_float_lt(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref c1(m), c2(m), x_is_nan(m), y_is_nan(m), x_is_zero(m), y_is_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_nan(y, y_is_nan);
      m_simp.mk_or(x_is_nan, y_is_nan, c1);
      mk_is_zero(x, x_is_zero);
      mk_is_zero(y, y_is_zero);
      m_simp.mk_and(x_is_zero, y_is_zero, c2);
  
      expr * x_sgn, * x_sig, * x_exp;
      expr * y_sgn, * y_sig, * y_exp;
      split_fp(x, x_sgn, x_exp, x_sig);
      split_fp(y, y_sgn, y_exp, y_sig);
  
      expr_ref c3(m), t3(m), t4(m), one_1(m), nil_1(m);
      one_1 = m_bv_util.mk_numeral(1, 1);
      nil_1 = m_bv_util.mk_numeral(0, 1);
      m_simp.mk_eq(x_sgn, one_1, c3);
  
      expr_ref y_sgn_eq_0(m), y_lt_x_exp(m), y_lt_x_sig(m), y_eq_x_exp(m), y_le_x_sig_exp(m), t3_or(m);
      m_simp.mk_eq(y_sgn, nil_1, y_sgn_eq_0);
      BVULT(y_exp, x_exp, y_lt_x_exp);
      BVULT(y_sig, x_sig, y_lt_x_sig);
      m_simp.mk_eq(y_exp, x_exp, y_eq_x_exp);
      m_simp.mk_and(y_eq_x_exp, y_lt_x_sig, y_le_x_sig_exp);
      m_simp.mk_or(y_lt_x_exp, y_le_x_sig_exp, t3_or);
      m_simp.mk_ite(y_sgn_eq_0, m.mk_true(), t3_or, t3);
  
      expr_ref y_sgn_eq_1(m), x_lt_y_exp(m), x_eq_y_exp(m), x_lt_y_sig(m), x_le_y_sig_exp(m), t4_or(m);
      m_simp.mk_eq(y_sgn, one_1, y_sgn_eq_1);
      BVULT(x_exp, y_exp, x_lt_y_exp);
      m_simp.mk_eq(x_exp, y_exp, x_eq_y_exp);
      BVULT(x_sig, y_sig, x_lt_y_sig);
      m_simp.mk_and(x_eq_y_exp, x_lt_y_sig, x_le_y_sig_exp);
      m_simp.mk_or(x_lt_y_exp, x_le_y_sig_exp, t4_or);
      m_simp.mk_ite(y_sgn_eq_1, m.mk_false(), t4_or, t4);
  
      expr_ref c3t3t4(m), c2else(m);
      m_simp.mk_ite(c3, t3, t4, c3t3t4);
      m_simp.mk_ite(c2, m.mk_false(), c3t3t4, c2else);
      m_simp.mk_ite(c1, m.mk_false(), c2else, result);
  }
  
  void fpa2bv_converter::mk_float_gt(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_float_gt(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_float_gt(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref t3(m);
      mk_float_le(s, x, y, t3);
  
      expr_ref nan_or(m), xy_zero(m), not_t3(m), r_else(m);
      expr_ref x_is_nan(m), y_is_nan(m), x_is_zero(m), y_is_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_nan(y, y_is_nan);
      m_simp.mk_or(x_is_nan, y_is_nan, nan_or);
      mk_is_zero(x, x_is_zero);
      mk_is_zero(y, y_is_zero);
      m_simp.mk_and(x_is_zero, y_is_zero, xy_zero);
      m_simp.mk_not(t3, not_t3);
      m_simp.mk_ite(xy_zero, m.mk_false(), not_t3, r_else);
      m_simp.mk_ite(nan_or, m.mk_false(), r_else, result);
  }
  
  void fpa2bv_converter::mk_float_le(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_float_le(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_float_le(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref a(m), b(m);
      mk_float_lt(s, x, y, a);
      mk_float_eq(s, x, y, b);
      m_simp.mk_or(a, b, result);
  }
  
  void fpa2bv_converter::mk_float_ge(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      expr_ref x(m), y(m);
      x = args[0];
      y = args[1];
      mk_float_ge(f->get_range(), x, y, result);
  }
  
  void fpa2bv_converter::mk_float_ge(sort * s, expr_ref & x, expr_ref & y, expr_ref & result) {
      expr_ref a(m), b(m);
      mk_float_gt(s, x, y, a);
      mk_float_eq(s, x, y, b);
      m_simp.mk_or(a, b, result);
  }
  
  void fpa2bv_converter::mk_is_zero(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      mk_is_zero(args[0], result);
  }
  
  void fpa2bv_converter::mk_is_nzero(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref a0_is_neg(m), a0_is_zero(m);
      mk_is_neg(args[0], a0_is_neg);
      mk_is_zero(args[0], a0_is_zero);
      m_simp.mk_and(a0_is_neg, a0_is_zero, result);
  }
  
  void fpa2bv_converter::mk_is_pzero(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref a0_is_pos(m), a0_is_zero(m);
      mk_is_pos(args[0], a0_is_pos);
      mk_is_zero(args[0], a0_is_zero);
      m_simp.mk_and(a0_is_pos, a0_is_zero, result);
  }
  
  void fpa2bv_converter::mk_is_nan(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      mk_is_nan(args[0], result);
  }
  
  void fpa2bv_converter::mk_is_inf(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      mk_is_inf(args[0], result);
  }
  
  void fpa2bv_converter::mk_is_normal(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      mk_is_normal(args[0], result);
  }
  
  void fpa2bv_converter::mk_is_subnormal(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      mk_is_denormal(args[0], result);
  }
  
  void fpa2bv_converter::mk_is_negative(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref t1(m), t2(m), nt1(m);
      mk_is_nan(args[0], t1);
      mk_is_neg(args[0], t2);
      nt1 = m.mk_not(t1);
      result = m.mk_and(nt1, t2);
      TRACE("fpa2bv_is_negative", tout << "result = " << mk_ismt2_pp(result, m) << std::endl;);
  }
  
  void fpa2bv_converter::mk_is_positive(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref t1(m), t2(m), nt1(m);
      mk_is_nan(args[0], t1);
      mk_is_pos(args[0], t2);
      nt1 = m.mk_not(t1);
      result = m.mk_and(nt1, t2);
  }
  
  void fpa2bv_converter::mk_to_fp(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_fp", for (unsigned i=0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl; );
  
      if (num == 1 &&
          m_bv_util.is_bv(args[0])) {
          sort * s = f->get_range();
          unsigned to_sbits = m_util.get_sbits(s);
          unsigned to_ebits = m_util.get_ebits(s);
  
          expr * bv = args[0];
          int sz = m_bv_util.get_bv_size(bv);
          (void)to_sbits;
          SASSERT((unsigned)sz == to_sbits + to_ebits);
  
          result = m_util.mk_fp(m_bv_util.mk_extract(sz - 1, sz - 1, bv),
                                m_bv_util.mk_extract(sz - 2, sz - to_ebits - 1, bv),
                                m_bv_util.mk_extract(sz - to_ebits - 2, 0, bv));
      }
      else if (num == 2 &&
          m_util.is_rm(args[0]) &&
          m_util.is_float(m.get_sort(args[1]))) {
          // rm + float -> float
          mk_to_fp_float(f, f->get_range(), args[0], args[1], result);
      }
      else if (num == 2 &&
          m_util.is_rm(args[0]) &&
          (m_arith_util.is_int(args[1]) ||
              m_arith_util.is_real(args[1]))) {
          // rm + real -> float
          mk_to_fp_real(f, f->get_range(), args[0], args[1], result);
      }
      else if (num == 2 &&
          m_util.is_rm(args[0]) &&
          m_bv_util.is_bv(args[1])) {
          // rm + signed bv -> float
          mk_to_fp_signed(f, num, args, result);
      }
      else if (num == 3 &&
          m_bv_util.is_bv(args[0]) &&
          m_bv_util.is_bv(args[1]) &&
          m_bv_util.is_bv(args[2])) {
          // 3 BV -> float
          SASSERT(m_bv_util.get_bv_size(args[0]) == 1);
          SASSERT(m_util.get_ebits(f->get_range()) == m_bv_util.get_bv_size(args[1]));
          SASSERT(m_util.get_sbits(f->get_range()) == m_bv_util.get_bv_size(args[2])+1);
          result = m_util.mk_fp(args[0], args[1], args[2]);
      }
      else if (num == 3 &&
          m_util.is_rm(args[0]) &&
          m_arith_util.is_numeral(args[1]) &&
          m_arith_util.is_numeral(args[2]))
      {
          // rm + real + int -> float
          mk_to_fp_real_int(f, num, args, result);
      }
      else
          UNREACHABLE();
  
      SASSERT(is_well_sorted(m, result));
  }
  
  
  void fpa2bv_converter::mk_to_fp_float(func_decl * f, sort * s, expr * rm, expr * x, expr_ref & result) {
      SASSERT(m_util.is_bv2rm(rm));
      mk_to_fp_float(s, to_app(rm)->get_arg(0), x, result);
  }
  
  void fpa2bv_converter::mk_to_fp_float(sort * to_srt, expr * rm, expr * x, expr_ref & result) {
      unsigned from_sbits = m_util.get_sbits(m.get_sort(x));
      unsigned from_ebits = m_util.get_ebits(m.get_sort(x));
      unsigned to_sbits = m_util.get_sbits(to_srt);
      unsigned to_ebits = m_util.get_ebits(to_srt);
  
      if (from_sbits == to_sbits && from_ebits == to_ebits)
          result = x;
      else {
          expr_ref c1(m), c2(m), c3(m), c4(m), c5(m);
          expr_ref v1(m), v2(m), v3(m), v4(m), v5(m), v6(m);
          expr_ref one1(m);
  
          one1 = m_bv_util.mk_numeral(1, 1);
          expr_ref ninf(m), pinf(m);
          mk_pinf(to_srt, pinf);
          mk_ninf(to_srt, ninf);
  
          // NaN -> NaN
          mk_is_nan(x, c1);
          mk_nan(to_srt, v1);
  
          // +0 -> +0
          mk_is_pzero(x, c2);
          mk_pzero(to_srt, v2);
  
          // -0 -> -0
          mk_is_nzero(x, c3);
          mk_nzero(to_srt, v3);
  
          // +oo -> +oo
          mk_is_pinf(x, c4);
          v4 = pinf;
  
          // -oo -> -oo
          mk_is_ninf(x, c5);
          v5 = ninf;
  
          // otherwise: the actual conversion with rounding.
          expr_ref sgn(m), sig(m), exp(m), lz(m);
          unpack(x, sgn, sig, exp, lz, true);
  
          dbg_decouple("fpa2bv_to_float_x_sgn", sgn);
          dbg_decouple("fpa2bv_to_float_x_sig", sig);
          dbg_decouple("fpa2bv_to_float_x_exp", exp);
          dbg_decouple("fpa2bv_to_float_lz", lz);
  
          expr_ref res_sgn(m), res_sig(m), res_exp(m);
  
          res_sgn = sgn;
  
          SASSERT(m_bv_util.get_bv_size(sgn) == 1);
          SASSERT(m_bv_util.get_bv_size(sig) == from_sbits);
          SASSERT(m_bv_util.get_bv_size(exp) == from_ebits);
          SASSERT(m_bv_util.get_bv_size(lz) == from_ebits);
  
          if (from_sbits < (to_sbits + 3)) {
              // make sure that sig has at least to_sbits + 3
              res_sig = m_bv_util.mk_concat(sig, m_bv_util.mk_numeral(0, to_sbits + 3 - from_sbits));
          }
          else if (from_sbits > (to_sbits + 3)) {
              // collapse the extra bits into a sticky bit.
              expr_ref sticky(m), low(m), high(m);
              high = m_bv_util.mk_extract(from_sbits - 1, from_sbits - to_sbits - 2, sig);
              SASSERT(m_bv_util.get_bv_size(high) == to_sbits + 2);
              low = m_bv_util.mk_extract(from_sbits - to_sbits - 3, 0, sig);
              sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, low.get());
              SASSERT(m_bv_util.get_bv_size(sticky) == 1);
              dbg_decouple("fpa2bv_to_float_sticky", sticky);
              res_sig = m_bv_util.mk_concat(high, sticky);
              SASSERT(m_bv_util.get_bv_size(res_sig) == to_sbits + 3);
          }
          else
              res_sig = sig;
  
          res_sig = m_bv_util.mk_zero_extend(1, res_sig); // extra zero in the front for the rounder.
          unsigned sig_sz = m_bv_util.get_bv_size(res_sig);
          (void) sig_sz;
          SASSERT(sig_sz == to_sbits + 4);
  
          expr_ref exponent_overflow(m), exponent_underflow(m);
          exponent_overflow = m.mk_false();
          exponent_underflow = m.mk_false();
  
          if (from_ebits < (to_ebits + 2)) {
              res_exp = m_bv_util.mk_sign_extend(to_ebits - from_ebits + 2, exp);
  
              // subtract lz for subnormal numbers.
              expr_ref lz_ext(m);
              lz_ext = m_bv_util.mk_zero_extend(to_ebits - from_ebits + 2, lz);
              res_exp = m_bv_util.mk_bv_sub(res_exp, lz_ext);
          }
          else if (from_ebits > (to_ebits + 2)) {
              unsigned ebits_diff = from_ebits - (to_ebits + 2);
  
              // subtract lz for subnormal numbers.
              expr_ref exp_sub_lz(m);
              exp_sub_lz = m_bv_util.mk_bv_sub(m_bv_util.mk_sign_extend(2, exp), m_bv_util.mk_sign_extend(2, lz));
              dbg_decouple("fpa2bv_to_float_exp_sub_lz", exp_sub_lz);
  
              // check whether exponent is within roundable (to_ebits+2) range.
              expr_ref max_exp(m), min_exp(m), exp_in_range(m);
              const mpz & z = m_mpf_manager.m_powers2(to_ebits + 1, true);
              max_exp = m_bv_util.mk_concat(
                  m_bv_util.mk_numeral(m_mpf_manager.m_powers2.m1(to_ebits, false), to_ebits + 1),
                  m_bv_util.mk_numeral(0, 1));
              min_exp = m_bv_util.mk_numeral(z + mpz(2), to_ebits+2);
              dbg_decouple("fpa2bv_to_float_max_exp", max_exp);
              dbg_decouple("fpa2bv_to_float_min_exp", min_exp);
  
              expr_ref first_ovf_exp(m), first_udf_exp(m);
              const mpz & ovft = m_mpf_manager.m_powers2.m1(to_ebits+1, false);
              first_ovf_exp = m_bv_util.mk_numeral(ovft, from_ebits+2);
              first_udf_exp = m_bv_util.mk_concat(
                  m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, ebits_diff + 3)),
                  m_bv_util.mk_numeral(1, to_ebits + 1));
              dbg_decouple("fpa2bv_to_float_first_ovf_exp", first_ovf_exp);
              dbg_decouple("fpa2bv_to_float_first_udf_exp", first_udf_exp);
  
              exp_in_range = m_bv_util.mk_extract(to_ebits + 1, 0, exp_sub_lz);
              SASSERT(m_bv_util.get_bv_size(exp_in_range) == to_ebits + 2);
  
              expr_ref ovf_cond(m), udf_cond(m);
              ovf_cond = m_bv_util.mk_sle(first_ovf_exp, exp_sub_lz);
              udf_cond = m_bv_util.mk_sle(exp_sub_lz, first_udf_exp);
              dbg_decouple("fpa2bv_to_float_exp_ovf", ovf_cond);
              dbg_decouple("fpa2bv_to_float_exp_udf", udf_cond);
  
              res_exp = exp_in_range;
              res_exp = m.mk_ite(ovf_cond, max_exp, res_exp);
              res_exp = m.mk_ite(udf_cond, min_exp, res_exp);
          }
          else { // from_ebits == (to_ebits + 2)
              res_exp = m_bv_util.mk_bv_sub(exp, lz);
          }
  
          SASSERT(m_bv_util.get_bv_size(res_exp) == to_ebits + 2);
          SASSERT(is_well_sorted(m, res_exp));
  
          dbg_decouple("fpa2bv_to_float_res_sig", res_sig);
          dbg_decouple("fpa2bv_to_float_res_exp", res_exp);
  
          expr_ref rounded(m);
          expr_ref rm_e(rm, m);
          round(to_srt, rm_e, res_sgn, res_sig, res_exp, rounded);
  
          expr_ref is_neg(m), sig_inf(m);
          m_simp.mk_eq(sgn, one1, is_neg);
          mk_ite(is_neg, ninf, pinf, sig_inf);
  
          mk_ite(exponent_overflow, sig_inf, rounded, v6);
  
          // And finally, we tie them together.
          mk_ite(c5, v5, v6, result);
          mk_ite(c4, v4, result, result);
          mk_ite(c3, v3, result, result);
          mk_ite(c2, v2, result, result);
          mk_ite(c1, v1, result, result);
      }
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_fp_real(func_decl * f, sort * s, expr * rm, expr * x, expr_ref & result) {
      TRACE("fpa2bv_to_fp_real", tout << "rm: " << mk_ismt2_pp(rm, m) << std::endl <<
          "x: " << mk_ismt2_pp(x, m) << std::endl;);
      SASSERT(m_util.is_float(s));
      SASSERT(au().is_real(x) || au().is_int(x));
      SASSERT(m_util.is_bv2rm(rm));
  
      expr * bv_rm = to_app(rm)->get_arg(0);
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
  
      if (m_bv_util.is_numeral(bv_rm) && m_util.au().is_numeral(x)) {
          rational tmp_rat; unsigned sz;
          m_bv_util.is_numeral(to_expr(bv_rm), tmp_rat, sz);
          SASSERT(tmp_rat.is_int32());
          SASSERT(sz == 3);
  
          mpf_rounding_mode mrm;
          switch ((BV_RM_VAL)tmp_rat.get_unsigned()) {
          case BV_RM_TIES_TO_AWAY: mrm = MPF_ROUND_NEAREST_TAWAY; break;
          case BV_RM_TIES_TO_EVEN: mrm = MPF_ROUND_NEAREST_TEVEN; break;
          case BV_RM_TO_NEGATIVE: mrm = MPF_ROUND_TOWARD_NEGATIVE; break;
          case BV_RM_TO_POSITIVE: mrm = MPF_ROUND_TOWARD_POSITIVE; break;
          case BV_RM_TO_ZERO: mrm = MPF_ROUND_TOWARD_ZERO; break;
          default: UNREACHABLE();
          }
  
          rational q;
          bool is_int;
          m_util.au().is_numeral(x, q, is_int);
  
          if (q.is_zero())
              return mk_pzero(f, result);
          else {
              scoped_mpf v(m_mpf_manager);
              m_util.fm().set(v, ebits, sbits, mrm, q.to_mpq());
  
              expr_ref sgn(m), sig(m), exp(m), unbiased_exp(m);
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v), ebits);
              mk_bias(unbiased_exp, exp);
  
              result = m_util.mk_fp(sgn, exp, sig);
          }
      }
      else if (m_util.au().is_numeral(x)) {
          rational q;
          bool is_int;
          m_util.au().is_numeral(x, q, is_int);
  
          if (m_util.au().is_zero(x))
              mk_pzero(f, result);
          else {
              expr_ref rm_nta(m), rm_nte(m), rm_tp(m), rm_tn(m), rm_tz(m);
              mk_is_rm(bv_rm, BV_RM_TIES_TO_AWAY, rm_nta);
              mk_is_rm(bv_rm, BV_RM_TIES_TO_EVEN, rm_nte);
              mk_is_rm(bv_rm, BV_RM_TO_POSITIVE, rm_tp);
              mk_is_rm(bv_rm, BV_RM_TO_NEGATIVE, rm_tn);
              mk_is_rm(bv_rm, BV_RM_TO_ZERO, rm_tz);
  
              scoped_mpf v_nta(m_mpf_manager), v_nte(m_mpf_manager), v_tp(m_mpf_manager);
              scoped_mpf v_tn(m_mpf_manager), v_tz(m_mpf_manager);
              m_util.fm().set(v_nta, ebits, sbits, MPF_ROUND_NEAREST_TAWAY, q.to_mpq());
              m_util.fm().set(v_nte, ebits, sbits, MPF_ROUND_NEAREST_TEVEN, q.to_mpq());
              m_util.fm().set(v_tp, ebits, sbits, MPF_ROUND_TOWARD_POSITIVE, q.to_mpq());
              m_util.fm().set(v_tn, ebits, sbits, MPF_ROUND_TOWARD_NEGATIVE, q.to_mpq());
              m_util.fm().set(v_tz, ebits, sbits, MPF_ROUND_TOWARD_ZERO, q.to_mpq());
  
              expr_ref v1(m), v2(m), v3(m), v4(m);
  
              expr_ref sgn(m), sig(m), exp(m), unbiased_exp(m);
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v_nta)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v_nta), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v_nta), ebits);
              mk_bias(unbiased_exp, exp);
              v1 = m_util.mk_fp(sgn, exp, sig);
  
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v_nte)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v_nte), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v_nte), ebits);
              mk_bias(unbiased_exp, exp);
              v2 = m_util.mk_fp(sgn, exp, sig);
  
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v_tp)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v_tp), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v_tp), ebits);
              mk_bias(unbiased_exp, exp);
              v3 = m_util.mk_fp(sgn, exp, sig);
  
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v_tn)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v_tn), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v_tn), ebits);
              mk_bias(unbiased_exp, exp);
              v4 = m_util.mk_fp(sgn, exp, sig);
  
              sgn = m_bv_util.mk_numeral((m_util.fm().sgn(v_tp)) ? 1 : 0, 1);
              sig = m_bv_util.mk_numeral(m_util.fm().sig(v_tp), sbits - 1);
              unbiased_exp = m_bv_util.mk_numeral(m_util.fm().exp(v_tp), ebits);
              mk_bias(unbiased_exp, exp);
  
              result = m_util.mk_fp(sgn, exp, sig);
              mk_ite(rm_tn, v4, result, result);
              mk_ite(rm_tp, v3, result, result);
              mk_ite(rm_nte, v2, result, result);
              mk_ite(rm_nta, v1, result, result);
          }
      }
      else {
          SASSERT(!m_arith_util.is_numeral(x));
          bv_util & bu = m_bv_util;
          arith_util & au = m_arith_util;
  
          expr_ref bv0(m), bv1(m), zero(m), two(m);
          bv0 = bu.mk_numeral(0, 1);
          bv1 = bu.mk_numeral(1, 1);
          zero = au.mk_numeral(rational(0), false);
          two = au.mk_numeral(rational(2), false);
  
          expr_ref sgn(m), sig(m), exp(m);
          sgn = mk_fresh_const("fpa2bv_to_fp_real_sgn", 1);
          sig = mk_fresh_const("fpa2bv_to_fp_real_sig", sbits + 4);
          exp = mk_fresh_const("fpa2bv_to_fp_real_exp", ebits + 2);
  
          expr_ref rme(bv_rm, m);
          round(s, rme, sgn, sig, exp, result);
  
          expr * e = m.mk_eq(m_util.mk_to_real(result), x);
          m_extra_assertions.push_back(e);
      }
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_fp_real_int(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      // rm + real + int -> float
      SASSERT(m_util.is_float(f->get_range()));
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
  
      SASSERT(m_util.is_bv2rm(args[0]));
      expr * bv_rm = to_app(args[0])->get_arg(0);
  
      SASSERT((m_arith_util.is_int(args[1]) && m_arith_util.is_real(args[2])) ||
              (m_arith_util.is_real(args[1]) && m_arith_util.is_int(args[2])));
  
      rational q, e;
  
      if (m_arith_util.is_int(args[1]) && m_arith_util.is_real(args[2])) {
          if (!m_arith_util.is_numeral(args[1], e) ||
              !m_arith_util.is_numeral(args[2], q))
              UNREACHABLE();
      }
      else {
          if (!m_arith_util.is_numeral(args[2], e) ||
              !m_arith_util.is_numeral(args[1], q))
              UNREACHABLE();
      }
  
      SASSERT(e.is_int64());
      SASSERT(m_mpz_manager.eq(e.to_mpq().denominator(), 1));
  
      if (q.is_zero())
          return mk_pzero(f, result);
      else {
          scoped_mpf nte(m_mpf_manager), nta(m_mpf_manager), tp(m_mpf_manager), tn(m_mpf_manager), tz(m_mpf_manager);
          m_mpf_manager.set(nte, ebits, sbits, MPF_ROUND_NEAREST_TEVEN, e.to_mpq().numerator(), q.to_mpq());
          m_mpf_manager.set(nta, ebits, sbits, MPF_ROUND_NEAREST_TAWAY, e.to_mpq().numerator(), q.to_mpq());
          m_mpf_manager.set(tp, ebits, sbits, MPF_ROUND_TOWARD_POSITIVE, e.to_mpq().numerator(), q.to_mpq());
          m_mpf_manager.set(tn, ebits, sbits, MPF_ROUND_TOWARD_NEGATIVE, e.to_mpq().numerator(), q.to_mpq());
          m_mpf_manager.set(tz, ebits, sbits, MPF_ROUND_TOWARD_ZERO, e.to_mpq().numerator(), q.to_mpq());
  
          app_ref a_nte(m), a_nta(m), a_tp(m), a_tn(m), a_tz(m);
          a_nte = m_plugin->mk_numeral(nte);
          a_nta = m_plugin->mk_numeral(nta);
          a_tp = m_plugin->mk_numeral(tp);
          a_tn = m_plugin->mk_numeral(tn);
          a_tz = m_plugin->mk_numeral(tz);
  
          expr_ref bv_nte(m), bv_nta(m), bv_tp(m), bv_tn(m), bv_tz(m);
          mk_numeral(a_nte->get_decl(), 0, nullptr, bv_nte);
          mk_numeral(a_nta->get_decl(), 0, nullptr, bv_nta);
          mk_numeral(a_tp->get_decl(), 0, nullptr, bv_tp);
          mk_numeral(a_tn->get_decl(), 0, nullptr, bv_tn);
          mk_numeral(a_tz->get_decl(), 0, nullptr, bv_tz);
  
          expr_ref c1(m), c2(m), c3(m), c4(m);
          c1 = m.mk_eq(bv_rm, m_bv_util.mk_numeral(BV_RM_TO_POSITIVE, 3));
          c2 = m.mk_eq(bv_rm, m_bv_util.mk_numeral(BV_RM_TO_POSITIVE, 3));
          c3 = m.mk_eq(bv_rm, m_bv_util.mk_numeral(BV_RM_TIES_TO_AWAY, 3));
          c4 = m.mk_eq(bv_rm, m_bv_util.mk_numeral(BV_RM_TIES_TO_EVEN, 3));
  
          mk_ite(c1, bv_tn, bv_tz, result);
          mk_ite(c2, bv_tp, result, result);
          mk_ite(c3, bv_nta, result, result);
          mk_ite(c4, bv_nte, result, result);
      }
  }
  
  void fpa2bv_converter::mk_to_real(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_real", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
      SASSERT(num == 1);
      SASSERT(f->get_num_parameters() == 0);
      SASSERT(is_app_of(args[0], m_plugin->get_family_id(), OP_FPA_FP));
  
      expr * x = args[0];
      sort * s = m.get_sort(x);
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
  
      sort * rs = m_arith_util.mk_real();
      expr_ref x_is_nan(m), x_is_inf(m), x_is_zero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_inf(x, x_is_inf);
      mk_is_zero(x, x_is_zero);
  
      expr_ref sgn(m), sig(m), exp(m), lz(m);
      unpack(x, sgn, sig, exp, lz, true);
      // sig is of the form [1].[sigbits]
  
      SASSERT(m_bv_util.get_bv_size(sgn) == 1);
      SASSERT(m_bv_util.get_bv_size(sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits);
  
      expr_ref rsig(m), bit(m), bit_eq_1(m), rsig_mul_2(m), zero(m), one(m), two(m), bv0(m), bv1(m);
      zero = m_arith_util.mk_numeral(rational(0), rs);
      one = m_arith_util.mk_numeral(rational(1), rs);
      two = m_arith_util.mk_numeral(rational(2), rs);
      bv0 = m_bv_util.mk_numeral(0, 1);
      bv1 = m_bv_util.mk_numeral(1, 1);
      rsig = one;
      for (unsigned i = sbits - 2; i != (unsigned)-1; i--) {
          bit = m_bv_util.mk_extract(i, i, sig);
          bit_eq_1 = m.mk_eq(bit, bv1);
          rsig_mul_2 = m_arith_util.mk_mul(rsig, two);
          rsig = m_arith_util.mk_add(rsig_mul_2,
              m.mk_ite(bit_eq_1, one, zero));
      }
  
      const mpz & p2 = fu().fm().m_powers2(sbits - 1);
      expr_ref ep2(m);
      ep2 = m_arith_util.mk_numeral(rational(p2), false);
      rsig = m_arith_util.mk_div(rsig, ep2);
      dbg_decouple("fpa2bv_to_real_ep2", ep2);
      dbg_decouple("fpa2bv_to_real_rsig", rsig);
  
      expr_ref exp_n(m), exp_p(m), exp_is_neg(m), exp_abs(m);
      exp_is_neg = m.mk_eq(m_bv_util.mk_extract(ebits - 1, ebits - 1, exp), bv1);
      dbg_decouple("fpa2bv_to_real_exp_is_neg", exp_is_neg);
      exp_p = m_bv_util.mk_sign_extend(1, exp);
      exp_n = m_bv_util.mk_bv_neg(exp_p);
      exp_abs = m.mk_ite(exp_is_neg, exp_n, exp_p);
      dbg_decouple("fpa2bv_to_real_exp_abs", exp);
      SASSERT(m_bv_util.get_bv_size(exp_abs) == ebits + 1);
  
      expr_ref exp2(m), exp2_mul_2(m), prev_bit(m);
      exp2 = zero;
      for (unsigned i = ebits; i != (unsigned)-1; i--) {
          bit = m_bv_util.mk_extract(i, i, exp_abs);
          bit_eq_1 = m.mk_eq(bit, bv1);
          exp2_mul_2 = m_arith_util.mk_mul(exp2, two);
          exp2 = m_arith_util.mk_add(exp2_mul_2,
              m.mk_ite(bit_eq_1, one, zero));
          prev_bit = bit;
      }
  
      expr_ref one_div_exp2(m);
      one_div_exp2 = m_arith_util.mk_div(one, exp2);
      exp2 = m.mk_ite(exp_is_neg, one_div_exp2, exp2);
      dbg_decouple("fpa2bv_to_real_exp2", exp2);
  
      expr_ref res(m), two_exp2(m), minus_res(m), sgn_is_1(m);
      two_exp2 = m_arith_util.mk_power(two, exp2);
      res = m_arith_util.mk_mul(rsig, two_exp2);
      minus_res = m_arith_util.mk_uminus(res);
      sgn_is_1 = m.mk_eq(sgn, bv1);
      res = m.mk_ite(sgn_is_1, minus_res, res);
      dbg_decouple("fpa2bv_to_real_sig_times_exp2", res);
  
      TRACE("fpa2bv_to_real", tout << "rsig = " << mk_ismt2_pp(rsig, m) << std::endl;
      tout << "exp2 = " << mk_ismt2_pp(exp2, m) << std::endl;);
  
      expr_ref unspec(m);
      mk_to_real_unspecified(f, num, args, unspec);
      result = m.mk_ite(x_is_zero, zero, res);
      result = m.mk_ite(x_is_inf, unspec, result);
      result = m.mk_ite(x_is_nan, unspec, result);
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_fp_signed(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_fp_signed", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
  
      // This is a conversion from signed bitvector to float:
      // ; from signed machine integer, represented as a 2's complement bit vector
      // ((_ to_fp eb sb) RoundingMode (_ BitVec m) (_ FloatingPoint eb sb))
      // Semantics:
      //    Let b in[[(_ BitVec m)]] and let n be the signed integer represented by b (in 2's complement format).
      //    [[(_ to_fp eb sb)]](r, b) = +/ -infinity if n is too large / too small to be represented as a finite
      //    number of [[(_ FloatingPoint eb sb)]]; [[(_ to_fp eb sb)]](r, x) = y otherwise, where y is the finite
      //    number such that [[fp.to_real]](y) is closest to n according to rounding mode r.
  
      SASSERT(num == 2);
      SASSERT(m_util.is_float(f->get_range()));
      SASSERT(m_util.is_bv2rm(args[0]));
      SASSERT(m_bv_util.is_bv(args[1]));
  
      expr_ref rm(m), x(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
  
      dbg_decouple("fpa2bv_to_fp_signed_x", x);
  
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
      unsigned bv_sz = m_bv_util.get_bv_size(x);
      SASSERT(m_bv_util.get_bv_size(rm) == 3);
  
      expr_ref bv0_1(m), bv1_1(m), bv0_sz(m), bv1_sz(m);
      bv0_1 = m_bv_util.mk_numeral(0, 1);
      bv1_1 = m_bv_util.mk_numeral(1, 1);
      bv0_sz = m_bv_util.mk_numeral(0, bv_sz);
      bv1_sz = m_bv_util.mk_numeral(1, bv_sz);
  
      expr_ref is_zero(m), nzero(m), pzero(m), ninf(m), pinf(m);
      is_zero = m.mk_eq(x, bv0_sz);
      mk_nzero(f, nzero);
      mk_pzero(f, pzero);
      mk_ninf(f, ninf);
      mk_pinf(f, pinf);
  
      // Special case: x == 0 -> p/n zero
      expr_ref c1(m), v1(m);
      c1 = is_zero;
      v1 = pzero;
  
      // Special case: x != 0
      expr_ref is_neg_bit(m), exp_too_large(m), sig_4(m), exp_2(m);
      expr_ref is_neg(m), x_abs(m), neg_x(m);
      is_neg_bit = m_bv_util.mk_extract(bv_sz - 1, bv_sz - 1, x);
      is_neg = m.mk_eq(is_neg_bit, bv1_1);
      neg_x = m_bv_util.mk_bv_neg(x); // overflow problem?
      x_abs = m.mk_ite(is_neg, neg_x, x);
      dbg_decouple("fpa2bv_to_fp_signed_is_neg", is_neg);
      // x_abs has an extra bit in the front.
      // x_abs is [bv_sz-1, bv_sz-2] . [bv_sz-3 ... 0] * 2^(bv_sz-2)
      // bv_sz-2 is the "1.0" bit for the rounder.
  
      expr_ref lz(m), e_bv_sz(m), e_rest_sz(m);
      mk_leading_zeros(x_abs, bv_sz, lz);
      e_bv_sz = m_bv_util.mk_numeral(bv_sz, bv_sz);
      e_rest_sz = m_bv_util.mk_bv_sub(e_bv_sz, lz);
      SASSERT(m_bv_util.get_bv_size(lz) == m_bv_util.get_bv_size(e_bv_sz));
      dbg_decouple("fpa2bv_to_fp_signed_lz", lz);
      expr_ref shifted_sig(m);
      shifted_sig = m_bv_util.mk_bv_shl(x_abs, lz);
  
      expr_ref sticky(m);
      // shifted_sig is [bv_sz-1, bv_sz-2] . [bv_sz-3 ... 0] * 2^(bv_sz-2) * 2^(-lz)
      unsigned sig_sz = sbits + 4; // we want extra rounding bits.
      if (sig_sz <= bv_sz) {
          expr_ref sig_rest(m);
          sig_4 = m_bv_util.mk_extract(bv_sz - 1, bv_sz - sig_sz + 1, shifted_sig); // one short
          sig_rest = m_bv_util.mk_extract(bv_sz - sig_sz, 0, shifted_sig);
          sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, sig_rest.get());
          sig_4 = m_bv_util.mk_concat(sig_4, sticky);
      }
      else {
          unsigned extra_bits = sig_sz - bv_sz;
          expr_ref extra_zeros(m);
          extra_zeros = m_bv_util.mk_numeral(0, extra_bits);
          sig_4 = m_bv_util.mk_concat(shifted_sig, extra_zeros);
          lz = m_bv_util.mk_bv_add(m_bv_util.mk_concat(extra_zeros, lz),
              m_bv_util.mk_numeral(extra_bits, sig_sz));
          bv_sz = bv_sz + extra_bits;
          SASSERT(is_well_sorted(m, lz));
      }
      SASSERT(m_bv_util.get_bv_size(sig_4) == sig_sz);
      dbg_decouple("fpa2bv_to_fp_signed_sig_4", sig_4);
  
      expr_ref s_exp(m), exp_rest(m);
      s_exp = m_bv_util.mk_bv_sub(m_bv_util.mk_numeral(bv_sz - 2, bv_sz), lz);
      // s_exp = (bv_sz-2) + (-lz) signed
      SASSERT(m_bv_util.get_bv_size(s_exp) == bv_sz);
      dbg_decouple("fpa2bv_to_fp_signed_s_exp", s_exp);
  
      unsigned exp_sz = ebits + 2; // (+2 for rounder)
      exp_2 = m_bv_util.mk_extract(exp_sz - 1, 0, s_exp);
      // the remaining bits are 0 if ebits is large enough.
      exp_too_large = m.mk_false();
  
      // The exponent is at most bv_sz, i.e., we need ld(bv_sz)+1 ebits.
      // exp < bv_sz (+sign bit which is [0])
      unsigned exp_worst_case_sz = (unsigned)((log((double)bv_sz) / log((double)2)) + 1.0);
  
      TRACE("fpa2bv_to_fp_signed", tout << "exp worst case sz: " << exp_worst_case_sz << std::endl;);
  
      if (exp_sz < exp_worst_case_sz) {
          // exp_sz < exp_worst_case_sz and exp >= 0.
          // Take the maximum legal exponent; this
          // allows us to keep the most precision.
          expr_ref max_exp(m), max_exp_bvsz(m), zero_sig_sz(m);
          mk_max_exp(exp_sz, max_exp);
          max_exp_bvsz = m_bv_util.mk_zero_extend(bv_sz - exp_sz, max_exp);
  
          exp_too_large = m_bv_util.mk_sle(
                              m_bv_util.mk_bv_add(max_exp_bvsz, m_bv_util.mk_numeral(1, bv_sz)),
                              s_exp);
          zero_sig_sz = m_bv_util.mk_numeral(0, sig_sz);
          sig_4 = m.mk_ite(exp_too_large, zero_sig_sz, sig_4);
          exp_2 = m.mk_ite(exp_too_large, max_exp, exp_2);
      }
      dbg_decouple("fpa2bv_to_fp_signed_exp_too_large", exp_too_large);
  
      expr_ref sgn(m), sig(m), exp(m);
      sgn = is_neg_bit;
      sig = sig_4;
      exp = exp_2;
  
      dbg_decouple("fpa2bv_to_fp_signed_sgn", sgn);
      dbg_decouple("fpa2bv_to_fp_signed_sig", sig);
      dbg_decouple("fpa2bv_to_fp_signed_exp", exp);
  
      SASSERT(m_bv_util.get_bv_size(sig) == sbits + 4);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits + 2);
  
      expr_ref v2(m);
      round(f->get_range(), rm, sgn, sig, exp, v2);
  
      mk_ite(c1, v1, v2, result);
  }
  
  void fpa2bv_converter::mk_to_fp_unsigned(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_fp_unsigned", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
  
      // This is a conversion from unsigned bitvector to float:
      // ((_ to_fp_unsigned eb sb) RoundingMode (_ BitVec m) (_ FloatingPoint eb sb))
      // Semantics:
      //    Let b in[[(_ BitVec m)]] and let n be the unsigned integer represented by b.
      //    [[(_ to_fp_unsigned eb sb)]](r, x) = +infinity if n is too large to be
      //    represented as a finite number of[[(_ FloatingPoint eb sb)]];
      //    [[(_ to_fp_unsigned eb sb)]](r, x) = y otherwise, where y is the finite number
      //    such that[[fp.to_real]](y) is closest to n according to rounding mode r.
  
      SASSERT(num == 2);
      SASSERT(m_util.is_float(f->get_range()));
      SASSERT(m_util.is_bv2rm(args[0]));
      SASSERT(m_bv_util.is_bv(args[1]));
  
      expr_ref rm(m), x(m);
      rm = to_app(args[0])->get_arg(0);
      x = args[1];
  
      dbg_decouple("fpa2bv_to_fp_unsigned_x", x);
  
      unsigned ebits = m_util.get_ebits(f->get_range());
      unsigned sbits = m_util.get_sbits(f->get_range());
      unsigned bv_sz = m_bv_util.get_bv_size(x);
      SASSERT(m_bv_util.get_bv_size(rm) == 3);
  
      expr_ref bv0_1(m), bv1_1(m), bv0_sz(m), bv1_sz(m);
      bv0_1 = m_bv_util.mk_numeral(0, 1);
      bv1_1 = m_bv_util.mk_numeral(1, 1);
      bv0_sz = m_bv_util.mk_numeral(0, bv_sz);
      bv1_sz = m_bv_util.mk_numeral(1, bv_sz);
  
      expr_ref is_zero(m), nzero(m), pzero(m), ninf(m), pinf(m);
      is_zero = m.mk_eq(x, bv0_sz);
      mk_nzero(f, nzero);
      mk_pzero(f, pzero);
      mk_ninf(f, ninf);
      mk_pinf(f, pinf);
  
      // Special case: x == 0 -> p/n zero
      expr_ref c1(m), v1(m);
      c1 = is_zero;
      v1 = pzero;
  
      // Special case: x != 0
      expr_ref exp_too_large(m), sig_4(m), exp_2(m);
      // x is [bv_sz-1] . [bv_sz-2 ... 0] * 2^(bv_sz-1)
      // bv_sz-1 is the "1.0" bit for the rounder.
  
      expr_ref lz(m), e_bv_sz(m), e_rest_sz(m);
      mk_leading_zeros(x, bv_sz, lz);
      e_bv_sz = m_bv_util.mk_numeral(bv_sz, bv_sz);
      e_rest_sz = m_bv_util.mk_bv_sub(e_bv_sz, lz);
      SASSERT(m_bv_util.get_bv_size(lz) == m_bv_util.get_bv_size(e_bv_sz));
      dbg_decouple("fpa2bv_to_fp_unsigned_lz", lz);
      expr_ref shifted_sig(m);
      shifted_sig = m_bv_util.mk_bv_shl(x, lz);
  
      expr_ref sticky(m);
      // shifted_sig is [bv_sz-1] . [bv_sz-2 ... 0] * 2^(bv_sz-1) * 2^(-lz)
      unsigned sig_sz = sbits + 4; // we want extra rounding bits.
      if (sig_sz <= bv_sz) {
          expr_ref sig_rest(m);
          sig_4 = m_bv_util.mk_extract(bv_sz - 1, bv_sz - sig_sz + 1, shifted_sig); // one short
          sig_rest = m_bv_util.mk_extract(bv_sz - sig_sz, 0, shifted_sig);
          sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, sig_rest.get());
          sig_4 = m_bv_util.mk_concat(sig_4, sticky);
      }
      else {
          unsigned extra_bits = sig_sz - bv_sz;
          expr_ref extra_zeros(m);
          extra_zeros = m_bv_util.mk_numeral(0, extra_bits);
          sig_4 = m_bv_util.mk_concat(shifted_sig, extra_zeros);
          lz = m_bv_util.mk_bv_add(m_bv_util.mk_concat(extra_zeros, lz),
              m_bv_util.mk_numeral(extra_bits, sig_sz));
          bv_sz = bv_sz + extra_bits;
          SASSERT(is_well_sorted(m, lz));
      }
      SASSERT(m_bv_util.get_bv_size(sig_4) == sig_sz);
  
      expr_ref s_exp(m), exp_rest(m);
      s_exp = m_bv_util.mk_bv_sub(m_bv_util.mk_numeral(bv_sz - 2, bv_sz), lz);
      // s_exp = (bv_sz-2) + (-lz) signed
      SASSERT(m_bv_util.get_bv_size(s_exp) == bv_sz);
  
      unsigned exp_sz = ebits + 2; // (+2 for rounder)
      exp_2 = m_bv_util.mk_extract(exp_sz - 1, 0, s_exp);
      // the remaining bits are 0 if ebits is large enough.
      exp_too_large = m.mk_false(); // This is always in range.
  
                                    // The exponent is at most bv_sz, i.e., we need ld(bv_sz)+1 ebits.
                                    // exp < bv_sz (+sign bit which is [0])
      unsigned exp_worst_case_sz = (unsigned)((log((double)bv_sz) / log((double)2)) + 1.0);
  
      if (exp_sz < exp_worst_case_sz) {
          // exp_sz < exp_worst_case_sz and exp >= 0.
          // Take the maximum legal exponent; this
          // allows us to keep the most precision.
          expr_ref max_exp(m), max_exp_bvsz(m), zero_sig_sz(m);
          mk_max_exp(exp_sz, max_exp);
          max_exp_bvsz = m_bv_util.mk_zero_extend(bv_sz - exp_sz, max_exp);
  
          exp_too_large = m_bv_util.mk_sle(m_bv_util.mk_bv_add(
              max_exp_bvsz,
              m_bv_util.mk_numeral(1, bv_sz)),
              s_exp);
          zero_sig_sz = m_bv_util.mk_numeral(0, sig_sz);
          sig_4 = m.mk_ite(exp_too_large, zero_sig_sz, sig_4);
          exp_2 = m.mk_ite(exp_too_large, max_exp, exp_2);
      }
      dbg_decouple("fpa2bv_to_fp_unsigned_exp_too_large", exp_too_large);
  
      expr_ref sgn(m), sig(m), exp(m);
      sgn = bv0_1;
      sig = sig_4;
      exp = exp_2;
  
      dbg_decouple("fpa2bv_to_fp_unsigned_sgn", sgn);
      dbg_decouple("fpa2bv_to_fp_unsigned_sig", sig);
      dbg_decouple("fpa2bv_to_fp_unsigned_exp", exp);
  
      SASSERT(m_bv_util.get_bv_size(sig) == sbits + 4);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits + 2);
  
      expr_ref v2(m);
      round(f->get_range(), rm, sgn, sig, exp, v2);
  
      mk_ite(c1, v1, v2, result);
  }
  
  void fpa2bv_converter::mk_to_ieee_bv(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      expr_ref x(m), x_is_nan(m);
      expr * sgn, * s, * e;
      x = args[0];
      split_fp(x, sgn, e, s);
      mk_is_nan(x, x_is_nan);
  
      expr_ref unspec(m);
      mk_to_ieee_bv_unspecified(f, num, args, unspec);
  
      expr_ref sgn_e_s(m);
      join_fp(x, sgn_e_s);
      m_simp.mk_ite(x_is_nan, unspec, sgn_e_s, result);
  
      TRACE("fpa2bv_to_ieee_bv", tout << "result=" << mk_ismt2_pp(result, m) << std::endl;);
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_ieee_bv_unspecified(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
      SASSERT(m_util.is_float(args[0]));
      unsigned ebits = f->get_domain()[0]->get_parameter(0).get_int();
      unsigned sbits = f->get_domain()[0]->get_parameter(1).get_int();
  
      if (m_hi_fp_unspecified) {
          mk_nan(f->get_domain()[0], result);
          join_fp(result, result);
      }
      else {
          expr_ref nw = nan_wrap(args[0]);
  
          sort * domain[1] = { m.get_sort(nw) };
          func_decl * f_bv = mk_bv_uf(f, domain, f->get_range());
          result = m.mk_app(f_bv, nw);
  
          expr_ref exp_bv(m), exp_all_ones(m);
          exp_bv = m_bv_util.mk_extract(ebits+sbits-2, sbits-1, result);
          exp_all_ones = m.mk_eq(exp_bv, m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, ebits)));
          m_extra_assertions.push_back(exp_all_ones);
  
          expr_ref sig_bv(m), sig_is_non_zero(m);
          sig_bv = m_bv_util.mk_extract(sbits-2, 0, result);
          sig_is_non_zero = m.mk_not(m.mk_eq(sig_bv, m_bv_util.mk_numeral(0, sbits-1)));
          m_extra_assertions.push_back(sig_is_non_zero);
      }
  
      TRACE("fpa2bv_to_ieee_bv_unspecified", tout << "result=" << mk_ismt2_pp(result, m) << std::endl;);
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_bv(func_decl * f, unsigned num, expr * const * args, bool is_signed, expr_ref & result) {
      TRACE("fpa2bv_to_bv", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
  
      SASSERT(num == 2);
      SASSERT(m_util.is_bv2rm(args[0]));
      SASSERT(m_util.is_float(args[1]));
  
      expr * rm = to_app(args[0])->get_arg(0);
      expr * x = args[1];
      sort * xs = m.get_sort(x);
      sort * bv_srt = f->get_range();
  
      unsigned ebits = m_util.get_ebits(xs);
      unsigned sbits = m_util.get_sbits(xs);
      unsigned bv_sz = (unsigned)f->get_parameter(0).get_int();
  
      expr_ref bv0(m), bv1(m);
      bv0 = m_bv_util.mk_numeral(0, 1);
      bv1 = m_bv_util.mk_numeral(1, 1);
  
      expr_ref x_is_nan(m), x_is_inf(m), x_is_zero(m), x_is_neg(m), x_is_nzero(m);
      mk_is_nan(x, x_is_nan);
      mk_is_inf(x, x_is_inf);
      mk_is_zero(x, x_is_zero);
      mk_is_neg(x, x_is_neg);
      mk_is_nzero(x, x_is_nzero);
  
      // NaN, Inf, or negative (except -0) -> unspecified
      expr_ref c1(m), v1(m), unspec_v(m);
      c1 = m.mk_or(x_is_nan, x_is_inf);
      mk_to_bv_unspecified(f, num, args, unspec_v);
      v1 = unspec_v;
      dbg_decouple("fpa2bv_to_bv_c1", c1);
  
      // +-0 -> 0
      expr_ref c2(m), v2(m);
      c2 = x_is_zero;
      v2 = m_bv_util.mk_numeral(rational(0), bv_srt);
      dbg_decouple("fpa2bv_to_bv_c2", c2);
  
      // Otherwise...
      expr_ref sgn(m), sig(m), exp(m), lz(m);
      unpack(x, sgn, sig, exp, lz, true);
  
      dbg_decouple("fpa2bv_to_bv_sgn", sgn);
      dbg_decouple("fpa2bv_to_bv_sig", sig);
      dbg_decouple("fpa2bv_to_bv_exp", exp);
      dbg_decouple("fpa2bv_to_bv_lz", lz);
  
      // sig is of the form +- [1].[sig] * 2^(exp-lz)
      SASSERT(m_bv_util.get_bv_size(sgn) == 1);
      SASSERT(m_bv_util.get_bv_size(sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits);
      SASSERT(m_bv_util.get_bv_size(lz) == ebits);
  
      unsigned sig_sz = sbits;
      if (sig_sz < (bv_sz + 3))
          sig = m_bv_util.mk_concat(sig, m_bv_util.mk_numeral(0, bv_sz-sig_sz+3));
      sig_sz = m_bv_util.get_bv_size(sig);
      SASSERT(sig_sz >= (bv_sz + 3));
  
      // x is of the form +- [1].[sig][r][g][s] ... and at least bv_sz + 3 long
  
      expr_ref exp_m_lz(m), e_m_lz_m_bv_sz(m), shift(m), is_neg_shift(m), big_sig(m);
      exp_m_lz = m_bv_util.mk_bv_sub(m_bv_util.mk_sign_extend(2, exp),
                                     m_bv_util.mk_zero_extend(2, lz));
  
      // big_sig is +- [... bv_sz+2 bits ...][1].[r][ ... sbits-1  ... ]
      big_sig = m_bv_util.mk_concat(m_bv_util.mk_zero_extend(bv_sz + 2, sig), bv0);
      unsigned big_sig_sz = sig_sz+1+bv_sz+2;
      SASSERT(m_bv_util.get_bv_size(big_sig) == big_sig_sz);
  
      is_neg_shift = m_bv_util.mk_sle(exp_m_lz, m_bv_util.mk_numeral(0, ebits+2));
      shift = m.mk_ite(is_neg_shift, m_bv_util.mk_bv_neg(exp_m_lz), exp_m_lz);
      if (ebits+2 < big_sig_sz)
          shift = m_bv_util.mk_zero_extend(big_sig_sz-ebits-2, shift);
      else if (ebits+2 > big_sig_sz) {
          expr_ref upper(m);
          upper = m_bv_util.mk_extract(big_sig_sz, ebits+2, shift);
          shift = m_bv_util.mk_extract(ebits+1, 0, shift);
          shift = m.mk_ite(m.mk_eq(upper, m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(upper))),
                           shift,
                           m_bv_util.mk_numeral(big_sig_sz-1, ebits+2));
      }
      dbg_decouple("fpa2bv_to_bv_shift_uncapped", shift);
      SASSERT(m_bv_util.get_bv_size(shift) == m_bv_util.get_bv_size(big_sig));
      dbg_decouple("fpa2bv_to_bv_big_sig", big_sig);
  
      expr_ref shift_limit(m);
      shift_limit = m_bv_util.mk_numeral(bv_sz+2, m_bv_util.get_bv_size(shift));
      shift = m.mk_ite(m_bv_util.mk_ule(shift, shift_limit), shift, shift_limit);
      dbg_decouple("fpa2bv_to_bv_shift_limit", shift_limit);
      dbg_decouple("fpa2bv_to_bv_is_neg_shift", is_neg_shift);
      dbg_decouple("fpa2bv_to_bv_shift", shift);
  
      expr_ref big_sig_shifted(m), int_part(m), last(m), round(m), stickies(m), sticky(m);
      big_sig_shifted = m.mk_ite(is_neg_shift, m_bv_util.mk_bv_lshr(big_sig, shift),
                                               m_bv_util.mk_bv_shl(big_sig, shift));
      int_part = m_bv_util.mk_extract(big_sig_sz-1, big_sig_sz-(bv_sz+3), big_sig_shifted);
      SASSERT(m_bv_util.get_bv_size(int_part) == bv_sz+3);
      last     = m_bv_util.mk_extract(big_sig_sz-(bv_sz+3), big_sig_sz-(bv_sz+3), big_sig_shifted);
      round    = m_bv_util.mk_extract(big_sig_sz-(bv_sz+4), big_sig_sz-(bv_sz+4), big_sig_shifted);
      stickies = m_bv_util.mk_extract(big_sig_sz-(bv_sz+5), 0, big_sig_shifted);
      sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, stickies.get());
      dbg_decouple("fpa2bv_to_bv_big_sig_shifted", big_sig_shifted);
      dbg_decouple("fpa2bv_to_bv_int_part", int_part);
      dbg_decouple("fpa2bv_to_bv_last", last);
      dbg_decouple("fpa2bv_to_bv_round", round);
      dbg_decouple("fpa2bv_to_bv_sticky", sticky);
  
      expr_ref rounding_decision(m);
      rounding_decision = mk_rounding_decision(rm, sgn, last, round, sticky);
      SASSERT(m_bv_util.get_bv_size(rounding_decision) == 1);
      dbg_decouple("fpa2bv_to_bv_rounding_decision", rounding_decision);
  
      expr_ref inc(m), pre_rounded(m);
      inc = m_bv_util.mk_zero_extend(bv_sz+2, rounding_decision);
      pre_rounded = m_bv_util.mk_bv_add(int_part, inc);
      dbg_decouple("fpa2bv_to_bv_inc", inc);
      dbg_decouple("fpa2bv_to_bv_pre_rounded", pre_rounded);
  
      expr_ref incd(m), pr_is_zero(m), ovfl(m);
      incd = m.mk_eq(rounding_decision, bv1);
      pr_is_zero = m.mk_eq(pre_rounded, m_bv_util.mk_numeral(0, bv_sz + 3));
      ovfl = m.mk_and(incd, pr_is_zero);
      dbg_decouple("fpa2bv_to_bv_incd", incd);
      dbg_decouple("fpa2bv_to_bv_ovfl", ovfl);
  
      expr_ref ul(m), in_range(m);
      if (!is_signed) {
          ul = m_bv_util.mk_zero_extend(3, m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, bv_sz)));
          in_range = m.mk_and(m.mk_not(x_is_neg), m.mk_not(ovfl),
                              m_bv_util.mk_ule(pre_rounded, ul));
      }
      else {
          expr_ref ll(m);
          ll = m_bv_util.mk_sign_extend(3, m_bv_util.mk_concat(bv1, m_bv_util.mk_numeral(0, bv_sz-1)));
          ul = m_bv_util.mk_zero_extend(4, m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, bv_sz-1)));
          ovfl = m.mk_or(ovfl, m_bv_util.mk_sle(pre_rounded, m_bv_util.mk_bv_neg(m_bv_util.mk_numeral(1, bv_sz + 3))));
          in_range = m.mk_and(m.mk_not(ovfl),
                              m_bv_util.mk_sle(ll, pre_rounded),
                              m_bv_util.mk_sle(pre_rounded, ul));
          dbg_decouple("fpa2bv_to_bv_in_range_ll", ll);
          pre_rounded = m.mk_ite(x_is_neg, m_bv_util.mk_bv_neg(pre_rounded), pre_rounded);
      }
      dbg_decouple("fpa2bv_to_bv_in_range_ovfl", ovfl);
      dbg_decouple("fpa2bv_to_bv_in_range_ul", ul);
      dbg_decouple("fpa2bv_to_bv_in_range", in_range);
  
      expr_ref rounded(m);
      rounded = m_bv_util.mk_extract(bv_sz-1, 0, pre_rounded);
      dbg_decouple("fpa2bv_to_bv_rounded", rounded);
  
      result = m.mk_ite(m.mk_not(in_range), unspec_v, rounded);
      result = m.mk_ite(c2, v2, result);
      result = m.mk_ite(c1, v1, result);
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_ubv(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_ubv", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
      mk_to_bv(f, num, args, false, result);
  }
  
  void fpa2bv_converter::mk_to_sbv(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      TRACE("fpa2bv_to_sbv", for (unsigned i = 0; i < num; i++)
          tout << "arg" << i << " = " << mk_ismt2_pp(args[i], m) << std::endl;);
      mk_to_bv(f, num, args, true, result);
  }
  
  expr_ref fpa2bv_converter::nan_wrap(expr * n) {
      expr_ref n_bv(m), arg_is_nan(m), nan(m), nan_bv(m), res(m);
      mk_is_nan(n, arg_is_nan);
      mk_nan(m.get_sort(n), nan);
      join_fp(nan, nan_bv);
      join_fp(n, n_bv);
      res = expr_ref(m.mk_ite(arg_is_nan, nan_bv, n_bv), m);
      SASSERT(is_well_sorted(m, res));
      return res;
  }
  
  void fpa2bv_converter::mk_to_bv_unspecified(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 2);
      SASSERT(m_util.is_bv2rm(args[0]));
      SASSERT(m_util.is_float(args[1]));
  
      if (m_hi_fp_unspecified)
          result = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(f->get_range()));
      else {
          expr * rm_bv = to_app(args[0])->get_arg(0);
          expr_ref nw = nan_wrap(args[1]);
          sort * domain[2] = { m.get_sort(rm_bv), m.get_sort(nw) };
          func_decl * f_bv = mk_bv_uf(f, domain, f->get_range());
          result = m.mk_app(f_bv, rm_bv, nw);
      }
  
      TRACE("fpa2bv_to_bv_unspecified", tout << "result=" << mk_ismt2_pp(result, m) << std::endl;);
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_to_real_unspecified(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 1);
  
      if (m_hi_fp_unspecified)
          result = m_arith_util.mk_numeral(rational(0), false);
      else {
          expr * n = args[0];
          expr_ref nw = nan_wrap(n);
          sort * domain[1] = { m.get_sort(nw) };
          func_decl * f_bv = mk_bv_uf(f, domain, f->get_range());
          result = m.mk_app(f_bv, nw);
      }
  }
  
  void fpa2bv_converter::mk_fp(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
      SASSERT(num == 3);
      SASSERT(m_bv_util.get_bv_size(args[0]) == 1);
      SASSERT(m_util.get_sbits(f->get_range()) == m_bv_util.get_bv_size(args[2]) + 1);
      SASSERT(m_util.get_ebits(f->get_range()) == m_bv_util.get_bv_size(args[1]));
      result = m_util.mk_fp(args[0], args[1], args[2]);
      TRACE("fpa2bv_mk_fp", tout << "mk_fp result = " << mk_ismt2_pp(result, m) << std::endl;);
  }
  
  void fpa2bv_converter::split_fp(expr * e, expr * & sgn, expr * & exp, expr * & sig) const {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
      sgn = to_app(e)->get_arg(0);
      exp = to_app(e)->get_arg(1);
      sig = to_app(e)->get_arg(2);
  }
  
  void fpa2bv_converter::split_fp(expr * e, expr_ref & sgn, expr_ref & exp, expr_ref & sig) const {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
      expr *e_sgn, *e_sig, *e_exp;
      split_fp(e, e_sgn, e_exp, e_sig);
      sgn = e_sgn;
      exp = e_exp;
      sig = e_sig;
  }
  
  void fpa2bv_converter::join_fp(expr * e, expr_ref & res) {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
      expr *sgn, *exp, *sig;
      split_fp(e, sgn, exp, sig);
      res = m_bv_util.mk_concat(m_bv_util.mk_concat(sgn, exp), sig);
  }
  
  void fpa2bv_converter::mk_is_nan(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
  
      // exp == 1^n , sig != 0
      expr_ref sig_is_zero(m), sig_is_not_zero(m), exp_is_top(m), top_exp(m), zero(m);
      mk_top_exp(m_bv_util.get_bv_size(exp), top_exp);
  
      zero = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(sig));
      m_simp.mk_eq(sig, zero, sig_is_zero);
      m_simp.mk_not(sig_is_zero, sig_is_not_zero);
      m_simp.mk_eq(exp, top_exp, exp_is_top);
      m_simp.mk_and(exp_is_top, sig_is_not_zero, result);
  }
  
  void fpa2bv_converter::mk_is_inf(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
      expr_ref eq1(m), eq2(m), top_exp(m), zero(m);
      mk_top_exp(m_bv_util.get_bv_size(exp), top_exp);
      zero = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(sig));
      m_simp.mk_eq(sig, zero, eq1);
      m_simp.mk_eq(exp, top_exp, eq2);
      m_simp.mk_and(eq1, eq2, result);
  }
  
  void fpa2bv_converter::mk_is_pinf(expr * e, expr_ref & result) {
      expr_ref e_is_pos(m), e_is_inf(m);
      mk_is_pos(e, e_is_pos);
      mk_is_inf(e, e_is_inf);
      m_simp.mk_and(e_is_pos, e_is_inf, result);
  }
  
  void fpa2bv_converter::mk_is_ninf(expr * e, expr_ref & result) {
      expr_ref e_is_neg(m), e_is_inf(m);
      mk_is_neg(e, e_is_neg);
      mk_is_inf(e, e_is_inf);
      m_simp.mk_and(e_is_neg, e_is_inf, result);
  }
  
  void fpa2bv_converter::mk_is_pos(expr * e, expr_ref & result) {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
      expr * a0 = to_app(e)->get_arg(0);
      expr_ref zero(m);
      zero = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(a0));
      m_simp.mk_eq(a0, zero, result);
  }
  
  void fpa2bv_converter::mk_is_neg(expr * e, expr_ref & result) {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
      expr * a0 = to_app(e)->get_arg(0);
      expr_ref one(m);
      one = m_bv_util.mk_numeral(1, m_bv_util.get_bv_size(a0));
      m_simp.mk_eq(a0, one, result);
  }
  
  void fpa2bv_converter::mk_is_zero(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
      expr_ref eq1(m), eq2(m), bot_exp(m), zero(m);
      mk_bot_exp(m_bv_util.get_bv_size(exp), bot_exp);
      zero = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(sig));
      m_simp.mk_eq(sig, zero, eq1);
      m_simp.mk_eq(exp, bot_exp, eq2);
      m_simp.mk_and(eq1, eq2, result);
  }
  
  void fpa2bv_converter::mk_is_nzero(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
      expr_ref e_is_zero(m), eq(m), one_1(m);
      mk_is_zero(e, e_is_zero);
      one_1 = m_bv_util.mk_numeral(1, 1);
      m_simp.mk_eq(sgn, one_1, eq);
      m_simp.mk_and(eq, e_is_zero, result);
  }
  
  void fpa2bv_converter::mk_is_pzero(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
      expr_ref e_is_zero(m), eq(m), nil_1(m);
      mk_is_zero(e, e_is_zero);
      nil_1 = m_bv_util.mk_numeral(0, 1);
      m_simp.mk_eq(sgn, nil_1, eq);
      m_simp.mk_and(eq, e_is_zero, result);
  }
  
  void fpa2bv_converter::mk_is_denormal(expr * e, expr_ref & result) {
      expr * sgn, *sig, *exp;
      split_fp(e, sgn, exp, sig);
  
      expr_ref zero(m), zexp(m), is_zero(m), n_is_zero(m);
      zero = m_bv_util.mk_numeral(0, m_bv_util.get_bv_size(exp));
      m_simp.mk_eq(exp, zero, result);
      m_simp.mk_eq(exp, zero, zexp);
      mk_is_zero(e, is_zero);
      m_simp.mk_not(is_zero, n_is_zero);
      m_simp.mk_and(n_is_zero, zexp, result);
  }
  
  void fpa2bv_converter::mk_is_normal(expr * e, expr_ref & result) {
      expr * sgn, * sig, * exp;
      split_fp(e, sgn, exp, sig);
  
      expr_ref is_special(m), is_denormal(m), p(m), is_zero(m);
      mk_is_denormal(e, is_denormal);
      mk_is_zero(e, is_zero);
      unsigned ebits = m_bv_util.get_bv_size(exp);
      p = m_bv_util.mk_numeral(fu().fm().m_powers2.m1(ebits), ebits);
      m_simp.mk_eq(exp, p, is_special);
  
      expr_ref or_ex(m);
      m_simp.mk_or(is_special, is_denormal, or_ex);
      m_simp.mk_or(is_zero, or_ex, or_ex);
      m_simp.mk_not(or_ex, result);
  }
  
  void fpa2bv_converter::mk_is_rm(expr * rme, BV_RM_VAL rm, expr_ref & result) {
      expr_ref rm_num(m);
      rm_num = m_bv_util.mk_numeral(rm, 3);
  
      switch(rm)
      {
      case BV_RM_TIES_TO_AWAY:
      case BV_RM_TIES_TO_EVEN:
      case BV_RM_TO_NEGATIVE:
      case BV_RM_TO_POSITIVE:
      case BV_RM_TO_ZERO:
          return m_simp.mk_eq(rme, rm_num, result);
      default:
          UNREACHABLE();
      }
  }
  
  void fpa2bv_converter::mk_top_exp(unsigned sz, expr_ref & result) {
      result = m_bv_util.mk_numeral(fu().fm().m_powers2.m1(sz), sz);
  }
  
  void fpa2bv_converter::mk_bot_exp(unsigned sz, expr_ref & result) {
      result = m_bv_util.mk_numeral(0, sz);
  }
  
  void fpa2bv_converter::mk_min_exp(unsigned ebits, expr_ref & result) {
      SASSERT(ebits >= 2);
      const mpz & z = m_mpf_manager.m_powers2.m1(ebits-1, true);
      result = m_bv_util.mk_numeral(z + mpz(1), ebits);
  }
  
  void fpa2bv_converter::mk_max_exp(unsigned ebits, expr_ref & result) {
      SASSERT(ebits >= 2);
      result = m_bv_util.mk_numeral(m_mpf_manager.m_powers2.m1(ebits-1, false), ebits);
  }
  
  void fpa2bv_converter::mk_leading_zeros(expr * e, unsigned max_bits, expr_ref & result) {
      SASSERT(m_bv_util.is_bv(e));
      unsigned bv_sz = m_bv_util.get_bv_size(e);
  
      if (bv_sz == 0)
          result = m_bv_util.mk_numeral(0, max_bits);
      else if (bv_sz == 1) {
          expr_ref eq(m), nil_1(m), one_m(m), nil_m(m);
          nil_1 = m_bv_util.mk_numeral(0, 1);
          one_m = m_bv_util.mk_numeral(1, max_bits);
          nil_m = m_bv_util.mk_numeral(0, max_bits);
          m_simp.mk_eq(e, nil_1, eq);
          m_simp.mk_ite(eq, one_m, nil_m, result);
      }
      else {
          expr_ref H(m), L(m);
          H = m_bv_util.mk_extract(bv_sz-1, bv_sz/2, e);
          L = m_bv_util.mk_extract(bv_sz/2-1, 0, e);
  
          unsigned H_size = m_bv_util.get_bv_size(H);
          // unsigned L_size = m_bv_util.get_bv_size(L);
  
          expr_ref lzH(m), lzL(m);
          mk_leading_zeros(H, max_bits, lzH); /* recursive! */
          mk_leading_zeros(L, max_bits, lzL);
  
          expr_ref H_is_zero(m), nil_h(m);
          nil_h = m_bv_util.mk_numeral(0, H_size);
          m_simp.mk_eq(H, nil_h, H_is_zero);
  
          expr_ref sum(m), h_m(m);
          h_m = m_bv_util.mk_numeral(H_size, max_bits);
          sum = m_bv_util.mk_bv_add(h_m, lzL);
          m_simp.mk_ite(H_is_zero, sum, lzH, result);
      }
  
      SASSERT(is_well_sorted(m, result));
  }
  
  void fpa2bv_converter::mk_bias(expr * e, expr_ref & result) {
      unsigned ebits = m_bv_util.get_bv_size(e);
      SASSERT(ebits >= 2);
  
      expr_ref bias(m);
      bias = m_bv_util.mk_numeral(fu().fm().m_powers2.m1(ebits-1), ebits);
      result = m_bv_util.mk_bv_add(e, bias);
  }
  
  void fpa2bv_converter::mk_unbias(expr * e, expr_ref & result) {
      unsigned ebits = m_bv_util.get_bv_size(e);
      SASSERT(ebits >= 2);
  
      expr_ref e_plus_one(m);
      e_plus_one = m_bv_util.mk_bv_add(e, m_bv_util.mk_numeral(1, ebits));
  
      expr_ref leading(m), n_leading(m), rest(m);
      leading = m_bv_util.mk_extract(ebits-1, ebits-1, e_plus_one);
      n_leading = m_bv_util.mk_bv_not(leading);
      rest = m_bv_util.mk_extract(ebits-2, 0, e_plus_one);
  
      result = m_bv_util.mk_concat(n_leading, rest);
  }
  
  void fpa2bv_converter::unpack(expr * e, expr_ref & sgn, expr_ref & sig, expr_ref & exp, expr_ref & lz, bool normalize) {
      SASSERT(m_util.is_fp(e));
      SASSERT(to_app(e)->get_num_args() == 3);
  
      sort * srt = to_app(e)->get_decl()->get_range();
      SASSERT(is_float(srt));
      unsigned sbits = m_util.get_sbits(srt);
      unsigned ebits = m_util.get_ebits(srt);
  
      split_fp(e, sgn, exp, sig);
  
      SASSERT(m_bv_util.get_bv_size(sgn) == 1);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits);
      SASSERT(m_bv_util.get_bv_size(sig) == sbits-1);
  
      dbg_decouple("fpa2bv_unpack_sgn", sgn);
      dbg_decouple("fpa2bv_unpack_exp", exp);
      dbg_decouple("fpa2bv_unpack_sig", sig);
  
      expr_ref is_normal(m);
      mk_is_normal(e, is_normal);
  
      expr_ref normal_sig(m), normal_exp(m);
      normal_sig = m_bv_util.mk_concat(m_bv_util.mk_numeral(1, 1), sig);
      mk_unbias(exp, normal_exp);
      dbg_decouple("fpa2bv_unpack_normal_exp", normal_exp);
  
      expr_ref denormal_sig(m), denormal_exp(m);
      denormal_sig = m_bv_util.mk_zero_extend(1, sig);
      denormal_exp = m_bv_util.mk_numeral(1, ebits);
      mk_unbias(denormal_exp, denormal_exp);
      dbg_decouple("fpa2bv_unpack_denormal_exp", denormal_exp);
  
      expr_ref zero_e(m);
      zero_e = m_bv_util.mk_numeral(0, ebits);
  
      if (normalize) {
          expr_ref is_sig_zero(m), zero_s(m);
          zero_s = m_bv_util.mk_numeral(0, sbits);
          m_simp.mk_eq(zero_s, denormal_sig, is_sig_zero);
  
          expr_ref lz_d(m), norm_or_zero(m);
          mk_leading_zeros(denormal_sig, ebits, lz_d);
          norm_or_zero = m.mk_or(is_normal, is_sig_zero);
          m_simp.mk_ite(norm_or_zero, zero_e, lz_d, lz);
          dbg_decouple("fpa2bv_unpack_lz", lz);
  
          expr_ref shift(m);
          m_simp.mk_ite(is_sig_zero, zero_e, lz, shift);
          dbg_decouple("fpa2bv_unpack_shift", shift);
          SASSERT(is_well_sorted(m, is_sig_zero));
          SASSERT(is_well_sorted(m, shift));
          SASSERT(m_bv_util.get_bv_size(shift) == ebits);
          if (ebits <= sbits) {
              expr_ref q(m);
              q = m_bv_util.mk_zero_extend(sbits-ebits, shift);
              denormal_sig = m_bv_util.mk_bv_shl(denormal_sig, q);
          }
          else {
              // the maximum shift is `sbits', because after that the mantissa
              // would be zero anyways. So we can safely cut the shift variable down,
              // as long as we check the higher bits.
              expr_ref zero_ems(m), sh(m), is_sh_zero(m), sl(m), sbits_s(m), short_shift(m);
              zero_ems = m_bv_util.mk_numeral(0, ebits - sbits);
              sbits_s = m_bv_util.mk_numeral(sbits, sbits);
              sh = m_bv_util.mk_extract(ebits-1, sbits, shift);
              m_simp.mk_eq(zero_ems, sh, is_sh_zero);
              short_shift = m_bv_util.mk_extract(sbits-1, 0, shift);
              m_simp.mk_ite(is_sh_zero, short_shift, sbits_s, sl);
              denormal_sig = m_bv_util.mk_bv_shl(denormal_sig, sl);
          }
      }
      else
          lz = zero_e;
  
      SASSERT(is_well_sorted(m, normal_sig));
      SASSERT(is_well_sorted(m, denormal_sig));
      SASSERT(is_well_sorted(m, normal_exp));
      SASSERT(is_well_sorted(m, denormal_exp));
  
      dbg_decouple("fpa2bv_unpack_is_normal", is_normal);
  
      m_simp.mk_ite(is_normal, normal_sig, denormal_sig, sig);
      m_simp.mk_ite(is_normal, normal_exp, denormal_exp, exp);
  
      SASSERT(is_well_sorted(m, sgn));
      SASSERT(is_well_sorted(m, sig));
      SASSERT(is_well_sorted(m, exp));
  
      SASSERT(m_bv_util.get_bv_size(sgn) == 1);
      SASSERT(m_bv_util.get_bv_size(sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits);
  
      TRACE("fpa2bv_unpack", tout << "UNPACK SGN = " << mk_ismt2_pp(sgn, m) << std::endl; );
      TRACE("fpa2bv_unpack", tout << "UNPACK SIG = " << mk_ismt2_pp(sig, m) << std::endl; );
      TRACE("fpa2bv_unpack", tout << "UNPACK EXP = " << mk_ismt2_pp(exp, m) << std::endl; );
  }
  
  void fpa2bv_converter::mk_rounding_mode(decl_kind k, expr_ref & result)
  {
      switch(k)
      {
      case OP_FPA_RM_NEAREST_TIES_TO_EVEN: result = m_bv_util.mk_numeral(BV_RM_TIES_TO_EVEN, 3); break;
      case OP_FPA_RM_NEAREST_TIES_TO_AWAY: result = m_bv_util.mk_numeral(BV_RM_TIES_TO_AWAY, 3); break;
      case OP_FPA_RM_TOWARD_POSITIVE: result = m_bv_util.mk_numeral(BV_RM_TO_POSITIVE, 3); break;
      case OP_FPA_RM_TOWARD_NEGATIVE: result = m_bv_util.mk_numeral(BV_RM_TO_NEGATIVE, 3); break;
      case OP_FPA_RM_TOWARD_ZERO: result = m_bv_util.mk_numeral(BV_RM_TO_ZERO, 3); break;
      default: UNREACHABLE();
      }
  
      result = m_util.mk_bv2rm(result);
  }
  
  void fpa2bv_converter::dbg_decouple(const char * prefix, expr_ref & e) {
  #ifdef Z3DEBUG
      return;
      // CMW: This works only for quantifier-free formulas.
      if (m_util.is_fp(e)) {
          expr_ref new_bv(m);
          expr *e_sgn, *e_sig, *e_exp;
          split_fp(e, e_sgn, e_exp, e_sig);
          unsigned ebits = m_bv_util.get_bv_size(e_exp);
          unsigned sbits = m_bv_util.get_bv_size(e_sig) + 1;
          unsigned bv_sz = ebits + sbits;
          new_bv = m.mk_fresh_const(prefix, m_bv_util.mk_sort(bv_sz));
          expr_ref bv_sgn(m), bv_exp(m), bv_sig(m);
          bv_sgn = m_bv_util.mk_extract(bv_sz-1, bv_sz-1, new_bv);
          bv_exp = m_bv_util.mk_extract(bv_sz-2, bv_sz-ebits-1, new_bv);
          bv_sig = m_bv_util.mk_extract(sbits-2, 0, new_bv);
  
          expr_ref e_sgn_eq_bv_sgn(m), e_exp_eq_bv_exp(m), e_sig_eq_bv_sig(m);
          e_sgn_eq_bv_sgn = m.mk_eq(e_sgn, bv_sgn);
          e_exp_eq_bv_exp = m.mk_eq(e_exp, bv_exp);
          e_sig_eq_bv_sig = m.mk_eq(e_sig, bv_sig);
          m_extra_assertions.push_back(e_sgn_eq_bv_sgn);
          m_extra_assertions.push_back(e_exp_eq_bv_exp);
          m_extra_assertions.push_back(e_sig_eq_bv_sig);
          e = m_util.mk_fp(bv_sgn, bv_exp, bv_sig);
      }
      else {
          expr_ref new_e(m), new_e_eq_e(m);
          new_e = m.mk_fresh_const(prefix, m.get_sort(e));
          new_e_eq_e = m.mk_eq(new_e, e);
          m_extra_assertions.push_back(new_e_eq_e);
          e = new_e;
      }
  #endif
  }
  
  expr_ref fpa2bv_converter::mk_rounding_decision(expr * rm, expr * sgn, expr * last, expr * round, expr * sticky) {
      expr_ref rmr(rm, m);
      expr_ref sgnr(sgn, m);
      expr_ref lastr(last, m);
      expr_ref roundr(round, m);
      expr_ref stickyr(sticky, m);
      dbg_decouple("fpa2bv_rnd_dec_rm", rmr);
      dbg_decouple("fpa2bv_rnd_dec_sgn", sgnr);
      dbg_decouple("fpa2bv_rnd_dec_last", lastr);
      dbg_decouple("fpa2bv_rnd_dec_round", roundr);
      dbg_decouple("fpa2bv_rnd_dec_sticky", stickyr);
  
      expr_ref last_or_sticky(m), round_or_sticky(m), not_last(m), not_round(m), not_sticky(m), not_lors(m), not_rors(m), not_sgn(m);
      expr * last_sticky[2] = { last, sticky };
      expr * round_sticky[2] = { round, sticky };
      last_or_sticky = m_bv_util.mk_bv_or(2, last_sticky);
      round_or_sticky = m_bv_util.mk_bv_or(2, round_sticky);
      not_last = m_bv_util.mk_bv_not(last);
      not_round = m_bv_util.mk_bv_not(round);
      not_sticky = m_bv_util.mk_bv_not(sticky);
      not_lors = m_bv_util.mk_bv_not(last_or_sticky);
      not_rors = m_bv_util.mk_bv_not(round_or_sticky);
      not_sgn = m_bv_util.mk_bv_not(sgn);
      expr * nround_lors[2] = { not_round, not_lors };
      expr * pos_args[2] = { sgn, not_rors };
      expr * neg_args[2] = { not_sgn, not_rors };
  
      expr_ref inc_teven(m), inc_taway(m), inc_pos(m), inc_neg(m);
      inc_teven = m_bv_util.mk_bv_not(m_bv_util.mk_bv_or(2, nround_lors));
      inc_taway = round;
      inc_pos = m_bv_util.mk_bv_not(m_bv_util.mk_bv_or(2, pos_args));
      inc_neg = m_bv_util.mk_bv_not(m_bv_util.mk_bv_or(2, neg_args));
  
      expr_ref res(m), inc_c2(m), inc_c3(m), inc_c4(m);
      expr_ref rm_is_to_neg(m), rm_is_to_pos(m), rm_is_away(m), rm_is_even(m), nil_1(m);
      nil_1 = m_bv_util.mk_numeral(0, 1);
      mk_is_rm(rm, BV_RM_TO_NEGATIVE, rm_is_to_neg);
      mk_is_rm(rm, BV_RM_TO_POSITIVE, rm_is_to_pos);
      mk_is_rm(rm, BV_RM_TIES_TO_AWAY, rm_is_away);
      mk_is_rm(rm, BV_RM_TIES_TO_EVEN, rm_is_even);
      m_simp.mk_ite(rm_is_to_neg, inc_neg, nil_1, inc_c4);
      m_simp.mk_ite(rm_is_to_pos, inc_pos, inc_c4, inc_c3);
      m_simp.mk_ite(rm_is_away, inc_taway, inc_c3, inc_c2);
      m_simp.mk_ite(rm_is_even, inc_teven, inc_c2, res);
  
      dbg_decouple("fpa2bv_rnd_dec_res", res);
      return res;
  }
  
  void fpa2bv_converter::round(sort * s, expr_ref & rm, expr_ref & sgn, expr_ref & sig, expr_ref & exp, expr_ref & result) {
      unsigned ebits = m_util.get_ebits(s);
      unsigned sbits = m_util.get_sbits(s);
  
      dbg_decouple("fpa2bv_rnd_rm", rm);
      dbg_decouple("fpa2bv_rnd_sgn", sgn);
      dbg_decouple("fpa2bv_rnd_sig", sig);
      dbg_decouple("fpa2bv_rnd_exp", exp);
  
      SASSERT(is_well_sorted(m, rm));
      SASSERT(is_well_sorted(m, sgn));
      SASSERT(is_well_sorted(m, sig));
      SASSERT(is_well_sorted(m, exp));
  
      TRACE("fpa2bv_dbg", tout << "RND: " << std::endl <<
          "ebits = " << ebits << std::endl <<
          "sbits = " << sbits << std::endl <<
          "sgn = " << mk_ismt2_pp(sgn, m) << std::endl <<
          "sig = " << mk_ismt2_pp(sig, m) << std::endl <<
          "exp = " << mk_ismt2_pp(exp, m) << std::endl; );
  
      // Assumptions: sig is of the form f[-1:0] . f[1:sbits-1] [guard,round,sticky],
      // i.e., it has 2 + (sbits-1) + 3 = sbits + 4 bits, where the first one is in sgn.
      // Furthermore, note that sig is an unsigned bit-vector, while exp is signed.
  
      SASSERT(m_bv_util.is_bv(rm) && m_bv_util.get_bv_size(rm) == 3);
      SASSERT(m_bv_util.is_bv(sgn) && m_bv_util.get_bv_size(sgn) == 1);
      SASSERT(m_bv_util.is_bv(sig) && m_bv_util.get_bv_size(sig) >= 5);
      SASSERT(m_bv_util.is_bv(exp) && m_bv_util.get_bv_size(exp) >= 4);
  
      SASSERT(m_bv_util.get_bv_size(sig) == sbits+4);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits+2);
  
      expr_ref e_min(m), e_max(m);
      mk_min_exp(ebits, e_min);
      mk_max_exp(ebits, e_max);
  
      TRACE("fpa2bv_dbg", tout << "e_min = " << mk_ismt2_pp(e_min, m) << std::endl;
                          tout << "e_max = " << mk_ismt2_pp(e_max, m) << std::endl;);
  
      expr_ref OVF1(m), e_top_three(m), sigm1(m), e_eq_emax_and_sigm1(m), e_eq_emax(m);
      expr_ref e3(m), ne3(m), e2(m), e1(m), e21(m), one_1(m), h_exp(m), sh_exp(m), th_exp(m);
      one_1 = m_bv_util.mk_numeral(1, 1);
      h_exp = m_bv_util.mk_extract(ebits+1, ebits+1, exp);
      sh_exp = m_bv_util.mk_extract(ebits, ebits, exp);
      th_exp = m_bv_util.mk_extract(ebits-1, ebits-1, exp);
      m_simp.mk_eq(h_exp, one_1, e3);
      m_simp.mk_eq(sh_exp, one_1, e2);
      m_simp.mk_eq(th_exp, one_1, e1);
      m_simp.mk_or(e2, e1, e21);
      m_simp.mk_not(e3, ne3);
      m_simp.mk_and(ne3, e21, e_top_three);
  
      expr_ref ext_emax(m), t_sig(m);
      ext_emax = m_bv_util.mk_zero_extend(2, e_max);
      t_sig = m_bv_util.mk_extract(sbits+3, sbits+3, sig);
      m_simp.mk_eq(ext_emax, exp, e_eq_emax);
      m_simp.mk_eq(t_sig, one_1, sigm1);
      m_simp.mk_and(e_eq_emax, sigm1, e_eq_emax_and_sigm1);
      m_simp.mk_or(e_top_three, e_eq_emax_and_sigm1, OVF1);
  
      dbg_decouple("fpa2bv_rnd_OVF1", OVF1);
  
      TRACE("fpa2bv_dbg", tout << "OVF1 = " << mk_ismt2_pp(OVF1, m) << std::endl;);
      SASSERT(is_well_sorted(m, OVF1));
  
      expr_ref lz(m);
      mk_leading_zeros(sig, ebits+2, lz); // CMW: is this always large enough?
  
      dbg_decouple("fpa2bv_rnd_lz", lz);
  
      TRACE("fpa2bv_dbg", tout << "LZ = " << mk_ismt2_pp(lz, m) << std::endl;);
  
      expr_ref t(m);
      t = m_bv_util.mk_bv_add(exp, m_bv_util.mk_numeral(1, ebits+2));
      t = m_bv_util.mk_bv_sub(t, lz);
      t = m_bv_util.mk_bv_sub(t, m_bv_util.mk_sign_extend(2, e_min));
      dbg_decouple("fpa2bv_rnd_t", t);
      expr_ref TINY(m);
      TINY = m_bv_util.mk_sle(t, m_bv_util.mk_numeral((unsigned)-1, ebits+2));
      dbg_decouple("fpa2bv_rnd_TINY", TINY);
      TRACE("fpa2bv_dbg", tout << "TINY = " << mk_ismt2_pp(TINY, m) << std::endl;);
      SASSERT(is_well_sorted(m, TINY));
  
      expr_ref beta(m);
      beta = m_bv_util.mk_bv_add(m_bv_util.mk_bv_sub(exp, lz), m_bv_util.mk_numeral(1, ebits+2));
  
      TRACE("fpa2bv_dbg", tout << "beta = " << mk_ismt2_pp(beta, m) << std::endl; );
      SASSERT(is_well_sorted(m, beta));
  
      dbg_decouple("fpa2bv_rnd_beta", beta);
      dbg_decouple("fpa2bv_rnd_e_min", e_min);
      dbg_decouple("fpa2bv_rnd_e_max", e_max);
  
      expr_ref sigma(m), sigma_add(m);
      sigma_add = m_bv_util.mk_bv_sub(exp, m_bv_util.mk_sign_extend(2, e_min));
      sigma_add = m_bv_util.mk_bv_add(sigma_add, m_bv_util.mk_numeral(1, ebits+2));
      m_simp.mk_ite(TINY, sigma_add, lz, sigma);
  
      dbg_decouple("fpa2bv_rnd_sigma", sigma);
  
      TRACE("fpa2bv_dbg", tout << "Shift distance: " << mk_ismt2_pp(sigma, m) << std::endl;);
      SASSERT(is_well_sorted(m, sigma));
  
      // Normalization shift
      dbg_decouple("fpa2bv_rnd_sig_before_shift", sig);
  
      unsigned sig_size = m_bv_util.get_bv_size(sig);
      SASSERT(sig_size == sbits + 4);
      SASSERT(m_bv_util.get_bv_size(sigma) == ebits+2);
      unsigned sigma_size = ebits + 2;
  
      expr_ref sigma_neg(m), sigma_cap(m), sigma_neg_capped(m), sigma_lt_zero(m), sig_ext(m),
          rs_sig(m), ls_sig(m), big_sh_sig(m), sigma_le_cap(m);
      sigma_neg = m_bv_util.mk_bv_neg(sigma);
      sigma_cap = m_bv_util.mk_numeral(sbits+2, sigma_size);
      sigma_le_cap = m_bv_util.mk_ule(sigma_neg, sigma_cap);
      m_simp.mk_ite(sigma_le_cap, sigma_neg, sigma_cap, sigma_neg_capped);
      dbg_decouple("fpa2bv_rnd_sigma_neg", sigma_neg);
      dbg_decouple("fpa2bv_rnd_sigma_cap", sigma_cap);
      dbg_decouple("fpa2bv_rnd_sigma_neg_capped", sigma_neg_capped);
      sigma_lt_zero = m_bv_util.mk_sle(sigma, m_bv_util.mk_numeral((unsigned)-1, sigma_size));
      dbg_decouple("fpa2bv_rnd_sigma_lt_zero", sigma_lt_zero);
  
      sig_ext = m_bv_util.mk_concat(sig, m_bv_util.mk_numeral(0, sig_size));
      rs_sig = m_bv_util.mk_bv_lshr(sig_ext, m_bv_util.mk_zero_extend(2*sig_size - sigma_size, sigma_neg_capped));
      ls_sig = m_bv_util.mk_bv_shl(sig_ext, m_bv_util.mk_zero_extend(2*sig_size - sigma_size, sigma));
      m_simp.mk_ite(sigma_lt_zero, rs_sig, ls_sig, big_sh_sig);
      SASSERT(m_bv_util.get_bv_size(big_sh_sig) == 2*sig_size);
  
      dbg_decouple("fpa2bv_rnd_big_sh_sig", big_sh_sig);
  
      unsigned sig_extract_low_bit = (2*sig_size-1)-(sbits+2)+1;
      sig = m_bv_util.mk_extract(2*sig_size-1, sig_extract_low_bit, big_sh_sig);
      SASSERT(m_bv_util.get_bv_size(sig) == sbits+2);
  
      dbg_decouple("fpa2bv_rnd_shifted_sig", sig);
  
      expr_ref sticky(m);
      sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, m_bv_util.mk_extract(sig_extract_low_bit-1, 0, big_sh_sig));
      SASSERT(is_well_sorted(m, sticky));
      SASSERT(is_well_sorted(m, sig));
  
      // put the sticky bit into the significand.
      expr_ref ext_sticky(m);
      ext_sticky = m_bv_util.mk_zero_extend(sbits+1, sticky);
      expr * tmp[2] = { sig, ext_sticky };
      sig = m_bv_util.mk_bv_or(2, tmp);
      SASSERT(is_well_sorted(m, sig));
      SASSERT(m_bv_util.get_bv_size(sig) == sbits+2);
  
      expr_ref ext_emin(m);
      ext_emin = m_bv_util.mk_zero_extend(2, e_min);
      m_simp.mk_ite(TINY, ext_emin, beta, exp);
      SASSERT(is_well_sorted(m, exp));
  
      // Significand rounding
      expr_ref round(m), last(m);
      sticky = m_bv_util.mk_extract(0, 0, sig); // new sticky bit!
      round = m_bv_util.mk_extract(1, 1, sig);
      last = m_bv_util.mk_extract(2, 2, sig);
  
      TRACE("fpa2bv_dbg", tout << "sticky = " << mk_ismt2_pp(sticky, m) << std::endl;);
  
      dbg_decouple("fpa2bv_rnd_sticky", sticky);
      dbg_decouple("fpa2bv_rnd_round", round);
      dbg_decouple("fpa2bv_rnd_last", last);
  
      sig = m_bv_util.mk_extract(sbits+1, 2, sig);
  
      expr_ref inc(m);
      inc = mk_rounding_decision(rm, sgn, last, round, sticky);
  
      SASSERT(m_bv_util.get_bv_size(inc) == 1 && is_well_sorted(m, inc));
      dbg_decouple("fpa2bv_rnd_inc", inc);
  
      sig = m_bv_util.mk_bv_add(m_bv_util.mk_zero_extend(1, sig),
          m_bv_util.mk_zero_extend(sbits, inc));
      SASSERT(is_well_sorted(m, sig));
      dbg_decouple("fpa2bv_rnd_sig_plus_inc", sig);
  
      // Post normalization
      SASSERT(m_bv_util.get_bv_size(sig) == sbits + 1);
      expr_ref SIGovf(m);
      t_sig = m_bv_util.mk_extract(sbits, sbits, sig);
      m_simp.mk_eq(t_sig, one_1, SIGovf);
      SASSERT(is_well_sorted(m, SIGovf));
      dbg_decouple("fpa2bv_rnd_SIGovf", SIGovf);
  
      expr_ref hallbut1_sig(m), lallbut1_sig(m);
      hallbut1_sig = m_bv_util.mk_extract(sbits, 1, sig);
      lallbut1_sig = m_bv_util.mk_extract(sbits-1, 0, sig);
      m_simp.mk_ite(SIGovf, hallbut1_sig, lallbut1_sig, sig);
  
      SASSERT(m_bv_util.get_bv_size(exp) == ebits + 2);
  
      expr_ref exp_p1(m);
      exp_p1 = m_bv_util.mk_bv_add(exp, m_bv_util.mk_numeral(1, ebits+2));
      m_simp.mk_ite(SIGovf, exp_p1, exp, exp);
  
      SASSERT(is_well_sorted(m, sig));
      SASSERT(is_well_sorted(m, exp));
      dbg_decouple("fpa2bv_rnd_sig_postnormalized", sig);
      dbg_decouple("fpa2bv_rnd_exp_postnormalized", exp);
  
      SASSERT(m_bv_util.get_bv_size(sig) == sbits);
      SASSERT(m_bv_util.get_bv_size(exp) == ebits + 2);
      SASSERT(m_bv_util.get_bv_size(e_max) == ebits);
  
      // Exponent adjustment and rounding
      expr_ref biased_exp(m);
      mk_bias(m_bv_util.mk_extract(ebits-1, 0, exp), biased_exp);
      dbg_decouple("fpa2bv_rnd_unbiased_exp", exp);
      dbg_decouple("fpa2bv_rnd_biased_exp", biased_exp);
  
      // AdjustExp
      SASSERT(is_well_sorted(m, OVF1));
      SASSERT(m.is_bool(OVF1));
  
      expr_ref preOVF2(m), OVF2(m), OVF(m), exp_redand(m), pem2m1(m);
      exp_redand = m.mk_app(m_bv_util.get_fid(), OP_BREDAND, biased_exp.get());
      m_simp.mk_eq(exp_redand, one_1, preOVF2);
      m_simp.mk_and(SIGovf, preOVF2, OVF2);
      pem2m1 = m_bv_util.mk_numeral(fu().fm().m_powers2.m1(ebits-2), ebits);
      m_simp.mk_ite(OVF2, pem2m1, biased_exp, biased_exp);
      m_simp.mk_or(OVF1, OVF2, OVF);
  
      SASSERT(is_well_sorted(m, OVF2));
      SASSERT(is_well_sorted(m, OVF));
  
      SASSERT(m.is_bool(OVF2));
      SASSERT(m.is_bool(OVF));
      dbg_decouple("fpa2bv_rnd_OVF2", OVF2);
      dbg_decouple("fpa2bv_rnd_OVF", OVF);
  
      // ExpRnd
      expr_ref top_exp(m), bot_exp(m);
      mk_top_exp(ebits, top_exp);
      mk_bot_exp(ebits, bot_exp);
  
      expr_ref nil_1(m);
      nil_1 = m_bv_util.mk_numeral(0, 1);
  
      expr_ref rm_is_to_zero(m), rm_is_to_neg(m), rm_is_to_pos(m), rm_zero_or_neg(m), rm_zero_or_pos(m);
      mk_is_rm(rm, BV_RM_TO_ZERO, rm_is_to_zero);
      mk_is_rm(rm, BV_RM_TO_NEGATIVE, rm_is_to_neg);
      mk_is_rm(rm, BV_RM_TO_POSITIVE, rm_is_to_pos);
      m_simp.mk_or(rm_is_to_zero, rm_is_to_neg, rm_zero_or_neg);
      m_simp.mk_or(rm_is_to_zero, rm_is_to_pos, rm_zero_or_pos);
      dbg_decouple("fpa2bv_rnd_rm_is_to_zero", rm_is_to_zero);
      dbg_decouple("fpa2bv_rnd_rm_is_to_neg", rm_is_to_neg);
      dbg_decouple("fpa2bv_rnd_rm_is_to_pos", rm_is_to_pos);
  
      expr_ref sgn_is_zero(m), zero1(m);
      zero1 = m_bv_util.mk_numeral(0, 1);
      m_simp.mk_eq(sgn, zero1, sgn_is_zero);
      dbg_decouple("fpa2bv_rnd_sgn_is_zero", sgn_is_zero);
  
      expr_ref max_sig(m), max_exp(m), inf_sig(m), inf_exp(m);
      max_sig = m_bv_util.mk_numeral(fu().fm().m_powers2.m1(sbits-1, false), sbits-1);
      max_exp = m_bv_util.mk_concat(m_bv_util.mk_numeral(fu().fm().m_powers2.m1(ebits-1, false), ebits-1),
          m_bv_util.mk_numeral(0, 1));
      inf_sig = m_bv_util.mk_numeral(0, sbits-1);
      inf_exp = top_exp;
  
      dbg_decouple("fpa2bv_rnd_max_exp", max_exp);
      dbg_decouple("fpa2bv_rnd_max_sig", max_sig);
      dbg_decouple("fpa2bv_rnd_inf_sig", inf_sig);
      dbg_decouple("fpa2bv_rnd_inf_exp", inf_exp);
  
      expr_ref ovfl_exp(m), max_inf_exp_neg(m), max_inf_exp_pos(m), n_d_check(m), n_d_exp(m);
      m_simp.mk_ite(rm_zero_or_pos, max_exp, inf_exp, max_inf_exp_neg);
      m_simp.mk_ite(rm_zero_or_neg, max_exp, inf_exp, max_inf_exp_pos);
      m_simp.mk_ite(sgn_is_zero, max_inf_exp_pos, max_inf_exp_neg, ovfl_exp);
      t_sig = m_bv_util.mk_extract(sbits-1, sbits-1, sig);
      m_simp.mk_eq(t_sig, nil_1, n_d_check);
      m_simp.mk_ite(n_d_check, bot_exp /* denormal */, biased_exp, n_d_exp);
      m_simp.mk_ite(OVF, ovfl_exp, n_d_exp, exp);
  
      expr_ref max_inf_sig_neg(m), max_inf_sig_pos(m), ovfl_sig(m), rest_sig(m);
      m_simp.mk_ite(rm_zero_or_pos, max_sig, inf_sig, max_inf_sig_neg);
      m_simp.mk_ite(rm_zero_or_neg, max_sig, inf_sig, max_inf_sig_pos);
      m_simp.mk_ite(sgn_is_zero, max_inf_sig_pos, max_inf_sig_neg, ovfl_sig);
      rest_sig = m_bv_util.mk_extract(sbits-2, 0, sig);
      m_simp.mk_ite(OVF, ovfl_sig, rest_sig, sig);
  
      dbg_decouple("fpa2bv_rnd_max_inf_sig_neg", max_inf_sig_neg);
      dbg_decouple("fpa2bv_rnd_max_inf_sig_pos", max_inf_sig_pos);
      dbg_decouple("fpa2bv_rnd_rm_zero_or_neg", rm_zero_or_neg);
      dbg_decouple("fpa2bv_rnd_rm_zero_or_pos", rm_zero_or_pos);
  
      dbg_decouple("fpa2bv_rnd_sgn_final", sgn);
      dbg_decouple("fpa2bv_rnd_sig_final", sig);
      dbg_decouple("fpa2bv_rnd_exp_final", exp);
  
      expr_ref res_sgn(m), res_sig(m), res_exp(m);
      res_sgn = sgn;
      res_sig = sig;
      res_exp = exp;
  
      SASSERT(m_bv_util.get_bv_size(res_sgn) == 1);
      SASSERT(is_well_sorted(m, res_sgn));
      SASSERT(m_bv_util.get_bv_size(res_sig) == sbits-1);
      SASSERT(is_well_sorted(m, res_sig));
      SASSERT(m_bv_util.get_bv_size(res_exp) == ebits);
      SASSERT(is_well_sorted(m, res_exp));
  
      result = m_util.mk_fp(res_sgn, res_exp, res_sig);
  
      TRACE("fpa2bv_round", tout << "ROUND = " << mk_ismt2_pp(result, m) << std::endl; );
  }
  
  void fpa2bv_converter::reset() {
      dec_ref_map_key_values(m, m_const2bv);
      dec_ref_map_key_values(m, m_rm_const2bv);
      dec_ref_map_key_values(m, m_uf2bvuf);
      for (obj_map<func_decl, std::pair<app*, app*> >::iterator it = m_min_max_ufs.begin();
          it != m_min_max_ufs.end();
          it++) {
          m.dec_ref(it->m_key);
          m.dec_ref(it->m_value.first);
          m.dec_ref(it->m_value.second);
      }
      m_min_max_ufs.reset();
      m_extra_assertions.reset();
  }
  
  func_decl * fpa2bv_converter::mk_bv_uf(func_decl * f, sort * const * domain, sort * range) {
      func_decl * res;
      if (!m_uf2bvuf.find(f, res)) {
          res = m.mk_fresh_func_decl(nullptr, f->get_arity(), domain, range);
          m_uf2bvuf.insert(f, res);
          m.inc_ref(f);
          m.inc_ref(res);
          TRACE("fpa2bv", tout << "New UF func_decl: " << std::endl << mk_ismt2_pp(res, m) << std::endl;);
      }
      return res;
  }
  