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GCC Code Coverage Report

Directory:	.		Exec	Total	Coverage
File:	src/preprocessing/passes/bool_to_bv.cpp	Lines:	176	182	96.7 %
Date:	2021-08-14	Branches:	408	783	52.1 %


/******************************************************************************
 * Top contributors (to current version):
 *   Makai Mann, Yoni Zohar, Clark Barrett
 *
 * This file is part of the cvc5 project.
 *
 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
 * in the top-level source directory and their institutional affiliations.
 * All rights reserved.  See the file COPYING in the top-level source
 * directory for licensing information.
 * ****************************************************************************
 *
 * The BoolToBV preprocessing pass.
 *
 */

#include "preprocessing/passes/bool_to_bv.h"

#include <string>

#include "base/map_util.h"
#include "expr/node.h"
#include "preprocessing/assertion_pipeline.h"
#include "preprocessing/preprocessing_pass_context.h"
#include "smt/smt_statistics_registry.h"
#include "theory/bv/theory_bv_utils.h"
#include "theory/rewriter.h"
#include "theory/theory.h"

namespace cvc5 {
namespace preprocessing {
namespace passes {
using namespace cvc5::theory;

BoolToBV::BoolToBV(PreprocessingPassContext* preprocContext)
    : PreprocessingPass(preprocContext, "bool-to-bv"), d_statistics()
{
  d_boolToBVMode = options::boolToBitvector();
};

PreprocessingPassResult BoolToBV::applyInternal(
    AssertionPipeline* assertionsToPreprocess)
{
  d_preprocContext->spendResource(Resource::PreprocessStep);

  size_t size = assertionsToPreprocess->size();

  if (d_boolToBVMode == options::BoolToBVMode::ALL)
  {
    for (size_t i = 0; i < size; ++i)
    {
      Node newAssertion = lowerAssertion((*assertionsToPreprocess)[i], true);
      assertionsToPreprocess->replace(i, Rewriter::rewrite(newAssertion));
    }
  }
  else
  {
    Assert(d_boolToBVMode == options::BoolToBVMode::ITE);
    for (size_t i = 0; i < size; ++i)
    {
      assertionsToPreprocess->replace(
          i, Rewriter::rewrite(lowerIte((*assertionsToPreprocess)[i])));
    }
  }

  return PreprocessingPassResult::NO_CONFLICT;
}

void BoolToBV::updateCache(TNode n, TNode rebuilt)
{
  // check more likely case first
  if ((n.getKind() != kind::ITE) || !n[1].getType().isBitVector())
  {
    d_lowerCache[n] = rebuilt;
  }
  else
  {
    d_iteBVLowerCache[n] = rebuilt;
  }
}

Node BoolToBV::fromCache(TNode n) const
{
  // check more likely case first
  if (n.getKind() != kind::ITE)
  {
    if (d_lowerCache.find(n) != d_lowerCache.end())
    {
      return d_lowerCache.at(n);
    }
  }
  else
  {
    if (d_iteBVLowerCache.find(n) != d_iteBVLowerCache.end())
    {
      return d_iteBVLowerCache.at(n);
    }
  }
  return n;
}

inline bool BoolToBV::inCache(const Node& n) const
{
  return (ContainsKey(d_lowerCache, n) || ContainsKey(d_iteBVLowerCache, n));
}

bool BoolToBV::needToRebuild(TNode n) const
{
  // check if any children were rebuilt
  for (const Node& nn : n)
  {
    if (inCache(nn))
    {
      return true;
    }
  }
  return false;
}

Node BoolToBV::lowerAssertion(const TNode& assertion, bool allowIteIntroduction)
{
  // first try to lower all the children
  for (const Node& c : assertion)
  {
    lowerNode(c, allowIteIntroduction);
  }

  // now try lowering the assertion, but don't force it with an ITE (even in mode all)
  lowerNode(assertion, false);
  Node newAssertion = fromCache(assertion);
  TypeNode newAssertionType = newAssertion.getType();
  if (newAssertionType.isBitVector())
  {
    Assert(newAssertionType.getBitVectorSize() == 1);
    newAssertion = NodeManager::currentNM()->mkNode(
        kind::EQUAL, newAssertion, bv::utils::mkOne(1));
    newAssertionType = newAssertion.getType();
  }
  Assert(newAssertionType.isBoolean());
  return newAssertion;
}

Node BoolToBV::lowerNode(const TNode& node, bool allowIteIntroduction)
{
  std::vector<TNode> to_visit;
  to_visit.push_back(node);
  std::unordered_set<TNode> visited;

  while (!to_visit.empty())
  {
    TNode n = to_visit.back();
    to_visit.pop_back();

    Debug("bool-to-bv") << "BoolToBV::lowerNode: Post-order traversal with "
                        << n << " and visited = " << ContainsKey(visited, n)
                        << std::endl;

    // Mark as visited
    if (ContainsKey(visited, n))
    {
      visit(n, allowIteIntroduction);
    }
    else
    {
      visited.insert(n);
      to_visit.push_back(n);

      // insert children in reverse order so that they're processed in order
      //    important for rewriting which sorts by node id
      // NOTE: size_t is unsigned, so using underflow for termination condition
      size_t numChildren = n.getNumChildren();
      for (size_t i = numChildren - 1; i < numChildren; --i)
      {
        to_visit.push_back(n[i]);
      }
    }
  }

  return fromCache(node);
}

void BoolToBV::visit(const TNode& n, bool allowIteIntroduction)
{
  Kind k = n.getKind();

  // easy case -- just replace boolean constant
  if (k == kind::CONST_BOOLEAN)
  {
    updateCache(n,
                (n == bv::utils::mkTrue()) ? bv::utils::mkOne(1)
                                           : bv::utils::mkZero(1));
    return;
  }

  NodeManager* nm = NodeManager::currentNM();
  Kind new_kind = k;
  switch (k)
  {
    case kind::EQUAL: new_kind = kind::BITVECTOR_COMP; break;
    case kind::AND: new_kind = kind::BITVECTOR_AND; break;
    case kind::OR: new_kind = kind::BITVECTOR_OR; break;
    case kind::NOT: new_kind = kind::BITVECTOR_NOT; break;
    case kind::XOR: new_kind = kind::BITVECTOR_XOR; break;
    case kind::IMPLIES: new_kind = kind::BITVECTOR_OR; break;
    case kind::ITE: new_kind = kind::BITVECTOR_ITE; break;
    case kind::BITVECTOR_ULT: new_kind = kind::BITVECTOR_ULTBV; break;
    case kind::BITVECTOR_SLT: new_kind = kind::BITVECTOR_SLTBV; break;
    case kind::BITVECTOR_ULE:
    case kind::BITVECTOR_UGT:
    case kind::BITVECTOR_UGE:
    case kind::BITVECTOR_SLE:
    case kind::BITVECTOR_SGT:
    case kind::BITVECTOR_SGE:
      // Should have been removed by rewriting.
      Unreachable();
    default: break;
  }

  // check if it's safe to lower or rebuild the node
  // Note: might have to rebuild to keep changes to children, even if this node
  // isn't being lowered

  // it's safe to lower if all the children are bit-vectors
  bool safe_to_lower =
      (new_kind != k);  // don't need to lower at all if kind hasn't changed

  // it's safe to rebuild if rebuilding doesn't change any of the types of the
  // children
  bool safe_to_rebuild = true;

  for (const Node& nn : n)
  {
    safe_to_lower = safe_to_lower && fromCache(nn).getType().isBitVector();
    safe_to_rebuild = safe_to_rebuild && (fromCache(nn).getType() == nn.getType());

    // if it's already not safe to do either, stop checking
    if (!safe_to_lower && !safe_to_rebuild)
    {
      break;
    }
  }

  Debug("bool-to-bv") << "safe_to_lower = " << safe_to_lower
                      << ", safe_to_rebuild = " << safe_to_rebuild << std::endl;

  if (new_kind != k && safe_to_lower)
  {
    // lower to BV
    rebuildNode(n, new_kind);
    return;
  }
  else if (new_kind != k && allowIteIntroduction && fromCache(n).getType().isBoolean())
  {
    // lower to BV using an ITE

    if (safe_to_rebuild && needToRebuild(n))
    {
      // need to rebuild to keep changes made to descendants
      rebuildNode(n, k);
    }

    updateCache(n,
                nm->mkNode(kind::ITE,
                           fromCache(n),
                           bv::utils::mkOne(1),
                           bv::utils::mkZero(1)));
    Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
                        << " =>\n"
                        << fromCache(n) << std::endl;
    if (d_boolToBVMode == options::BoolToBVMode::ALL)
    {
      // this statistic only makes sense for ALL mode
      ++(d_statistics.d_numIntroducedItes);
    }
    return;
  }
  else if (safe_to_rebuild && needToRebuild(n))
  {
    // rebuild to incorporate changes to children
    Assert(k == new_kind);
    rebuildNode(n, k);
  }
  else if (allowIteIntroduction && fromCache(n).getType().isBoolean())
  {
    // force booleans (which haven't already been converted) to bit-vector
    // needed to maintain the invariant that all boolean children
    // have been converted (even constants and variables) when forcing
    // with ITE introductions
    updateCache(
        n, nm->mkNode(kind::ITE, n, bv::utils::mkOne(1), bv::utils::mkZero(1)));
    Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
                        << " =>\n"
                        << fromCache(n) << std::endl;
    if (d_boolToBVMode == options::BoolToBVMode::ALL)
    {
      // this statistic only makes sense for ALL mode
      ++(d_statistics.d_numIntroducedItes);
    }
  }
  else
  {
    // do nothing
    Debug("bool-to-bv") << "BoolToBV::visit skipping: " << n
                        << std::endl;
  }
}

Node BoolToBV::lowerIte(const TNode& node)
{
  std::vector<TNode> visit;
  visit.push_back(node);
  std::unordered_set<TNode> visited;

  while (!visit.empty())
  {
    TNode n = visit.back();
    visit.pop_back();

    Debug("bool-to-bv") << "BoolToBV::lowerIte: Post-order traversal with " << n
                        << " and visited = " << ContainsKey(visited, n)
                        << std::endl;

    // Look for ITEs and mark visited
    if (!ContainsKey(visited, n))
    {
      if ((n.getKind() == kind::ITE) && n[1].getType().isBitVector())
      {
        Debug("bool-to-bv") << "BoolToBV::lowerIte: adding " << n[0]
                            << " to set of ite conditions" << std::endl;
        // don't force in this case -- forcing only introduces more ITEs
        Node loweredNode = lowerNode(n, false);
        // some of the lowered nodes might appear elsewhere but not in an ITE
        // reset the cache to prevent lowering them
        // the bit-vector ITEs are still tracked in d_iteBVLowerCache though
        d_lowerCache.clear();
      }
      else
      {
        visit.push_back(n);
        visited.insert(n);
        // insert in reverse order so that they're processed in order
        for (int i = n.getNumChildren() - 1; i >= 0; --i)
        {
          visit.push_back(n[i]);
        }
      }
    }
    else if (needToRebuild(n))
    {
      // Note: it's always safe to rebuild here, because we've only lowered
      //       ITEs of type bit-vector to BITVECTOR_ITE
      rebuildNode(n, n.getKind());
    }
    else
    {
      Debug("bool-to-bv")
          << "BoolToBV::lowerIte Skipping because don't need to rebuild: " << n
          << std::endl;
    }
  }
  return fromCache(node);
}

void BoolToBV::rebuildNode(const TNode& n, Kind new_kind)
{
  Kind k = n.getKind();
  NodeManager* nm = NodeManager::currentNM();
  NodeBuilder builder(new_kind);

  Debug("bool-to-bv") << "BoolToBV::rebuildNode with " << n
                      << " and new_kind = " << kindToString(new_kind)
                      << std::endl;

  if ((d_boolToBVMode == options::BoolToBVMode::ALL) && (new_kind != k))
  {
    // this statistic only makes sense for ALL mode
    ++(d_statistics.d_numTermsLowered);
  }

  if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
  {
    builder << n.getOperator();
  }

  // special case IMPLIES because needs to be rewritten
  if ((k == kind::IMPLIES) && (new_kind != k))
  {
    builder << nm->mkNode(kind::BITVECTOR_NOT, fromCache(n[0]));
    builder << fromCache(n[1]);
  }
  else
  {
    for (const Node& nn : n)
    {
      builder << fromCache(nn);
    }
  }

  Debug("bool-to-bv") << "BoolToBV::rebuildNode " << n << " =>\n"
                      << builder << std::endl;

  updateCache(n, builder.constructNode());
}

BoolToBV::Statistics::Statistics()
    : d_numIteToBvite(smtStatisticsRegistry().registerInt(
        "preprocessing::passes::BoolToBV::NumIteToBvite")),
      // the following two statistics are not correct in the ITE mode, because
      // we might discard rebuilt nodes if we fails to convert a bool to
      // width-one bit-vector (never forces)
      d_numTermsLowered(smtStatisticsRegistry().registerInt(
          "preprocessing::passes:BoolToBV::NumTermsLowered")),
      d_numIntroducedItes(smtStatisticsRegistry().registerInt(
          "preprocessing::passes::BoolToBV::NumTermsForcedLowered"))
{
}

}  // namespace passes
}  // namespace preprocessing
}  // namespace cvc5


Generated by: GCOVR (Version 3.2)

Line	Exec	Source
1		/******************************************************************************
2		* Top contributors (to current version):
3		* Makai Mann, Yoni Zohar, Clark Barrett
4		*
5		* This file is part of the cvc5 project.
6		*
7		* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
8		* in the top-level source directory and their institutional affiliations.
9		* All rights reserved. See the file COPYING in the top-level source
10		* directory for licensing information.
11		* ****************************************************************************
12		*
13		* The BoolToBV preprocessing pass.
14		*
15		*/
16
17		#include "preprocessing/passes/bool_to_bv.h"
18
19		#include <string>
20
21		#include "base/map_util.h"
22		#include "expr/node.h"
23		#include "preprocessing/assertion_pipeline.h"
24		#include "preprocessing/preprocessing_pass_context.h"
25		#include "smt/smt_statistics_registry.h"
26		#include "theory/bv/theory_bv_utils.h"
27		#include "theory/rewriter.h"
28		#include "theory/theory.h"
29
30		namespace cvc5 {
31		namespace preprocessing {
32		namespace passes {
33		using namespace cvc5::theory;
34
35	9853	BoolToBV::BoolToBV(PreprocessingPassContext* preprocContext)
36	9853	: PreprocessingPass(preprocContext, "bool-to-bv"), d_statistics()
37		{
38	9853	d_boolToBVMode = options::boolToBitvector();
39	9853	};
40
41	12	PreprocessingPassResult BoolToBV::applyInternal(
42		AssertionPipeline* assertionsToPreprocess)
43		{
44	12	d_preprocContext->spendResource(Resource::PreprocessStep);
45
46	12	size_t size = assertionsToPreprocess->size();
47
48	12	if (d_boolToBVMode == options::BoolToBVMode::ALL)
49		{
50	74	for (size_t i = 0; i < size; ++i)
51		{
52	132	Node newAssertion = lowerAssertion((*assertionsToPreprocess)[i], true);
53	66	assertionsToPreprocess->replace(i, Rewriter::rewrite(newAssertion));
54		}
55		}
56		else
57		{
58	4	Assert(d_boolToBVMode == options::BoolToBVMode::ITE);
59	24	for (size_t i = 0; i < size; ++i)
60		{
61	20	assertionsToPreprocess->replace(
62	40	i, Rewriter::rewrite(lowerIte((*assertionsToPreprocess)[i])));
63		}
64		}
65
66	12	return PreprocessingPassResult::NO_CONFLICT;
67		}
68
69	158	void BoolToBV::updateCache(TNode n, TNode rebuilt)
70		{
71		// check more likely case first
72	158	if ((n.getKind() != kind::ITE) \|\| !n[1].getType().isBitVector())
73		{
74	154	d_lowerCache[n] = rebuilt;
75		}
76		else
77		{
78	4	d_iteBVLowerCache[n] = rebuilt;
79		}
80	158	}
81
82	1342	Node BoolToBV::fromCache(TNode n) const
83		{
84		// check more likely case first
85	1342	if (n.getKind() != kind::ITE)
86		{
87	1326	if (d_lowerCache.find(n) != d_lowerCache.end())
88		{
89	734	return d_lowerCache.at(n);
90		}
91		}
92		else
93		{
94	16	if (d_iteBVLowerCache.find(n) != d_iteBVLowerCache.end())
95		{
96	8	return d_iteBVLowerCache.at(n);
97		}
98		}
99	600	return n;
100		}
101
102	216	inline bool BoolToBV::inCache(const Node& n) const
103		{
104	216	return (ContainsKey(d_lowerCache, n) \|\| ContainsKey(d_iteBVLowerCache, n));
105		}
106
107	536	bool BoolToBV::needToRebuild(TNode n) const
108		{
109		// check if any children were rebuilt
110	748	for (const Node& nn : n)
111		{
112	216	if (inCache(nn))
113		{
114	4	return true;
115		}
116		}
117	532	return false;
118		}
119
120	66	Node BoolToBV::lowerAssertion(const TNode& assertion, bool allowIteIntroduction)
121		{
122		// first try to lower all the children
123	168	for (const Node& c : assertion)
124		{
125	102	lowerNode(c, allowIteIntroduction);
126		}
127
128		// now try lowering the assertion, but don't force it with an ITE (even in mode all)
129	66	lowerNode(assertion, false);
130	66	Node newAssertion = fromCache(assertion);
131	132	TypeNode newAssertionType = newAssertion.getType();
132	66	if (newAssertionType.isBitVector())
133		{
134	62	Assert(newAssertionType.getBitVectorSize() == 1);
135	124	newAssertion = NodeManager::currentNM()->mkNode(
136	124	kind::EQUAL, newAssertion, bv::utils::mkOne(1));
137	62	newAssertionType = newAssertion.getType();
138		}
139	66	Assert(newAssertionType.isBoolean());
140	132	return newAssertion;
141		}
142
143	172	Node BoolToBV::lowerNode(const TNode& node, bool allowIteIntroduction)
144		{
145	344	std::vector<TNode> to_visit;
146	172	to_visit.push_back(node);
147	344	std::unordered_set<TNode> visited;
148
149	2540	while (!to_visit.empty())
150		{
151	2368	TNode n = to_visit.back();
152	1184	to_visit.pop_back();
153
154	2368	Debug("bool-to-bv") << "BoolToBV::lowerNode: Post-order traversal with "
155	2368	<< n << " and visited = " << ContainsKey(visited, n)
156	1184	<< std::endl;
157
158		// Mark as visited
159	1184	if (ContainsKey(visited, n))
160		{
161	614	visit(n, allowIteIntroduction);
162		}
163		else
164		{
165	570	visited.insert(n);
166	570	to_visit.push_back(n);
167
168		// insert children in reverse order so that they're processed in order
169		// important for rewriting which sorts by node id
170		// NOTE: size_t is unsigned, so using underflow for termination condition
171	570	size_t numChildren = n.getNumChildren();
172	1012	for (size_t i = numChildren - 1; i < numChildren; --i)
173		{
174	442	to_visit.push_back(n[i]);
175		}
176		}
177		}
178
179	344	return fromCache(node);
180		}
181
182	614	void BoolToBV::visit(const TNode& n, bool allowIteIntroduction)
183		{
184	614	Kind k = n.getKind();
185
186		// easy case -- just replace boolean constant
187	614	if (k == kind::CONST_BOOLEAN)
188		{
189	10	updateCache(n,
190	20	(n == bv::utils::mkTrue()) ? bv::utils::mkOne(1)
191		: bv::utils::mkZero(1));
192	132	return;
193		}
194
195	604	NodeManager* nm = NodeManager::currentNM();
196	604	Kind new_kind = k;
197	604	switch (k)
198		{
199	38	case kind::EQUAL: new_kind = kind::BITVECTOR_COMP; break;
200	10	case kind::AND: new_kind = kind::BITVECTOR_AND; break;
201	4	case kind::OR: new_kind = kind::BITVECTOR_OR; break;
202	26	case kind::NOT: new_kind = kind::BITVECTOR_NOT; break;
203	6	case kind::XOR: new_kind = kind::BITVECTOR_XOR; break;
204	20	case kind::IMPLIES: new_kind = kind::BITVECTOR_OR; break;
205	12	case kind::ITE: new_kind = kind::BITVECTOR_ITE; break;
206	16	case kind::BITVECTOR_ULT: new_kind = kind::BITVECTOR_ULTBV; break;
207	4	case kind::BITVECTOR_SLT: new_kind = kind::BITVECTOR_SLTBV; break;
208		case kind::BITVECTOR_ULE:
209		case kind::BITVECTOR_UGT:
210		case kind::BITVECTOR_UGE:
211		case kind::BITVECTOR_SLE:
212		case kind::BITVECTOR_SGT:
213		case kind::BITVECTOR_SGE:
214		// Should have been removed by rewriting.
215		Unreachable();
216	468	default: break;
217		}
218
219		// check if it's safe to lower or rebuild the node
220		// Note: might have to rebuild to keep changes to children, even if this node
221		// isn't being lowered
222
223		// it's safe to lower if all the children are bit-vectors
224	604	bool safe_to_lower =
225	604	(new_kind != k); // don't need to lower at all if kind hasn't changed
226
227		// it's safe to rebuild if rebuilding doesn't change any of the types of the
228		// children
229	604	bool safe_to_rebuild = true;
230
231	998	for (const Node& nn : n)
232		{
233	434	safe_to_lower = safe_to_lower && fromCache(nn).getType().isBitVector();
234	434	safe_to_rebuild = safe_to_rebuild && (fromCache(nn).getType() == nn.getType());
235
236		// if it's already not safe to do either, stop checking
237	434	if (!safe_to_lower && !safe_to_rebuild)
238		{
239	40	break;
240		}
241		}
242
243	1208	Debug("bool-to-bv") << "safe_to_lower = " << safe_to_lower
244	604	<< ", safe_to_rebuild = " << safe_to_rebuild << std::endl;
245
246	604	if (new_kind != k && safe_to_lower)
247		{
248		// lower to BV
249	104	rebuildNode(n, new_kind);
250	104	return;
251		}
252	500	else if (new_kind != k && allowIteIntroduction && fromCache(n).getType().isBoolean())
253		{
254		// lower to BV using an ITE
255
256	8	if (safe_to_rebuild && needToRebuild(n))
257		{
258		// need to rebuild to keep changes made to descendants
259		rebuildNode(n, k);
260		}
261
262	8	updateCache(n,
263	48	nm->mkNode(kind::ITE,
264	16	fromCache(n),
265	16	bv::utils::mkOne(1),
266	16	bv::utils::mkZero(1)));
267	16	Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
268	8	<< " =>\n"
269	8	<< fromCache(n) << std::endl;
270	8	if (d_boolToBVMode == options::BoolToBVMode::ALL)
271		{
272		// this statistic only makes sense for ALL mode
273	8	++(d_statistics.d_numIntroducedItes);
274		}
275	8	return;
276		}
277	492	else if (safe_to_rebuild && needToRebuild(n))
278		{
279		// rebuild to incorporate changes to children
280		Assert(k == new_kind);
281		rebuildNode(n, k);
282		}
283	492	else if (allowIteIntroduction && fromCache(n).getType().isBoolean())
284		{
285		// force booleans (which haven't already been converted) to bit-vector
286		// needed to maintain the invariant that all boolean children
287		// have been converted (even constants and variables) when forcing
288		// with ITE introductions
289	32	updateCache(
290	64	n, nm->mkNode(kind::ITE, n, bv::utils::mkOne(1), bv::utils::mkZero(1)));
291	64	Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
292	32	<< " =>\n"
293	32	<< fromCache(n) << std::endl;
294	32	if (d_boolToBVMode == options::BoolToBVMode::ALL)
295		{
296		// this statistic only makes sense for ALL mode
297	32	++(d_statistics.d_numIntroducedItes);
298		}
299		}
300		else
301		{
302		// do nothing
303	920	Debug("bool-to-bv") << "BoolToBV::visit skipping: " << n
304	460	<< std::endl;
305		}
306		}
307
308	20	Node BoolToBV::lowerIte(const TNode& node)
309		{
310	40	std::vector<TNode> visit;
311	20	visit.push_back(node);
312	40	std::unordered_set<TNode> visited;
313
314	316	while (!visit.empty())
315		{
316	296	TNode n = visit.back();
317	148	visit.pop_back();
318
319	296	Debug("bool-to-bv") << "BoolToBV::lowerIte: Post-order traversal with " << n
320	296	<< " and visited = " << ContainsKey(visited, n)
321	148	<< std::endl;
322
323		// Look for ITEs and mark visited
324	148	if (!ContainsKey(visited, n))
325		{
326	72	if ((n.getKind() == kind::ITE) && n[1].getType().isBitVector())
327		{
328	8	Debug("bool-to-bv") << "BoolToBV::lowerIte: adding " << n[0]
329	4	<< " to set of ite conditions" << std::endl;
330		// don't force in this case -- forcing only introduces more ITEs
331	8	Node loweredNode = lowerNode(n, false);
332		// some of the lowered nodes might appear elsewhere but not in an ITE
333		// reset the cache to prevent lowering them
334		// the bit-vector ITEs are still tracked in d_iteBVLowerCache though
335	4	d_lowerCache.clear();
336		}
337		else
338		{
339	68	visit.push_back(n);
340	68	visited.insert(n);
341		// insert in reverse order so that they're processed in order
342	128	for (int i = n.getNumChildren() - 1; i >= 0; --i)
343		{
344	60	visit.push_back(n[i]);
345		}
346		}
347		}
348	76	else if (needToRebuild(n))
349		{
350		// Note: it's always safe to rebuild here, because we've only lowered
351		// ITEs of type bit-vector to BITVECTOR_ITE
352	4	rebuildNode(n, n.getKind());
353		}
354		else
355		{
356	144	Debug("bool-to-bv")
357	72	<< "BoolToBV::lowerIte Skipping because don't need to rebuild: " << n
358	72	<< std::endl;
359		}
360		}
361	40	return fromCache(node);
362		}
363
364	108	void BoolToBV::rebuildNode(const TNode& n, Kind new_kind)
365		{
366	108	Kind k = n.getKind();
367	108	NodeManager* nm = NodeManager::currentNM();
368	216	NodeBuilder builder(new_kind);
369
370	216	Debug("bool-to-bv") << "BoolToBV::rebuildNode with " << n
371	216	<< " and new_kind = " << kindToString(new_kind)
372	108	<< std::endl;
373
374	108	if ((d_boolToBVMode == options::BoolToBVMode::ALL) && (new_kind != k))
375		{
376		// this statistic only makes sense for ALL mode
377	96	++(d_statistics.d_numTermsLowered);
378		}
379
380	108	if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
381		{
382		builder << n.getOperator();
383		}
384
385		// special case IMPLIES because needs to be rewritten
386	108	if ((k == kind::IMPLIES) && (new_kind != k))
387		{
388	20	builder << nm->mkNode(kind::BITVECTOR_NOT, fromCache(n[0]));
389	20	builder << fromCache(n[1]);
390		}
391		else
392		{
393	250	for (const Node& nn : n)
394		{
395	162	builder << fromCache(nn);
396		}
397		}
398
399	216	Debug("bool-to-bv") << "BoolToBV::rebuildNode " << n << " =>\n"
400	108	<< builder << std::endl;
401
402	108	updateCache(n, builder.constructNode());
403	108	}
404
405	9853	BoolToBV::Statistics::Statistics()
406	9853	: d_numIteToBvite(smtStatisticsRegistry().registerInt(
407	19706	"preprocessing::passes::BoolToBV::NumIteToBvite")),
408		// the following two statistics are not correct in the ITE mode, because
409		// we might discard rebuilt nodes if we fails to convert a bool to
410		// width-one bit-vector (never forces)
411	9853	d_numTermsLowered(smtStatisticsRegistry().registerInt(
412	19706	"preprocessing::passes:BoolToBV::NumTermsLowered")),
413	9853	d_numIntroducedItes(smtStatisticsRegistry().registerInt(
414	29559	"preprocessing::passes::BoolToBV::NumTermsForcedLowered"))
415		{
416	9853	}
417
418		} // namespace passes
419		} // namespace preprocessing
420	29340	} // namespace cvc5