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GCC Code Coverage Report

Directory:	.		Exec	Total	Coverage
File:	src/preprocessing/passes/bool_to_bv.cpp	Lines:	173	179	96.6 %
Date:	2021-09-15	Branches:	409	785	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 "options/bv_options.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(statisticsRegistry())
{
  d_boolToBVMode = options().bv.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, rewrite(newAssertion));
    }
  }
  else
  {
    Assert(d_boolToBVMode == options::BoolToBVMode::ITE);
    for (size_t i = 0; i < size; ++i)
    {
      assertionsToPreprocess->replace(
          i, 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(StatisticsRegistry& reg)
    : d_numIteToBvite(
        reg.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(
          reg.registerInt("preprocessing::passes:BoolToBV::NumTermsLowered")),
      d_numIntroducedItes(reg.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 "options/bv_options.h"
24		#include "preprocessing/assertion_pipeline.h"
25		#include "preprocessing/preprocessing_pass_context.h"
26		#include "smt/smt_statistics_registry.h"
27		#include "theory/bv/theory_bv_utils.h"
28		#include "theory/rewriter.h"
29		#include "theory/theory.h"
30
31		namespace cvc5 {
32		namespace preprocessing {
33		namespace passes {
34		using namespace cvc5::theory;
35
36	9942	BoolToBV::BoolToBV(PreprocessingPassContext* preprocContext)
37		: PreprocessingPass(preprocContext, "bool-to-bv"),
38	9942	d_statistics(statisticsRegistry())
39		{
40	9942	d_boolToBVMode = options().bv.boolToBitvector;
41	9942	};
42
43	12	PreprocessingPassResult BoolToBV::applyInternal(
44		AssertionPipeline* assertionsToPreprocess)
45		{
46	12	d_preprocContext->spendResource(Resource::PreprocessStep);
47
48	12	size_t size = assertionsToPreprocess->size();
49
50	12	if (d_boolToBVMode == options::BoolToBVMode::ALL)
51		{
52	74	for (size_t i = 0; i < size; ++i)
53		{
54	132	Node newAssertion = lowerAssertion((*assertionsToPreprocess)[i], true);
55	66	assertionsToPreprocess->replace(i, rewrite(newAssertion));
56		}
57		}
58		else
59		{
60	4	Assert(d_boolToBVMode == options::BoolToBVMode::ITE);
61	24	for (size_t i = 0; i < size; ++i)
62		{
63	20	assertionsToPreprocess->replace(
64	40	i, rewrite(lowerIte((*assertionsToPreprocess)[i])));
65		}
66		}
67
68	12	return PreprocessingPassResult::NO_CONFLICT;
69		}
70
71	158	void BoolToBV::updateCache(TNode n, TNode rebuilt)
72		{
73		// check more likely case first
74	158	if ((n.getKind() != kind::ITE) \|\| !n[1].getType().isBitVector())
75		{
76	154	d_lowerCache[n] = rebuilt;
77		}
78		else
79		{
80	4	d_iteBVLowerCache[n] = rebuilt;
81		}
82	158	}
83
84	1342	Node BoolToBV::fromCache(TNode n) const
85		{
86		// check more likely case first
87	1342	if (n.getKind() != kind::ITE)
88		{
89	1326	if (d_lowerCache.find(n) != d_lowerCache.end())
90		{
91	734	return d_lowerCache.at(n);
92		}
93		}
94		else
95		{
96	16	if (d_iteBVLowerCache.find(n) != d_iteBVLowerCache.end())
97		{
98	8	return d_iteBVLowerCache.at(n);
99		}
100		}
101	600	return n;
102		}
103
104	216	inline bool BoolToBV::inCache(const Node& n) const
105		{
106	216	return (ContainsKey(d_lowerCache, n) \|\| ContainsKey(d_iteBVLowerCache, n));
107		}
108
109	536	bool BoolToBV::needToRebuild(TNode n) const
110		{
111		// check if any children were rebuilt
112	748	for (const Node& nn : n)
113		{
114	216	if (inCache(nn))
115		{
116	4	return true;
117		}
118		}
119	532	return false;
120		}
121
122	66	Node BoolToBV::lowerAssertion(const TNode& assertion, bool allowIteIntroduction)
123		{
124		// first try to lower all the children
125	168	for (const Node& c : assertion)
126		{
127	102	lowerNode(c, allowIteIntroduction);
128		}
129
130		// now try lowering the assertion, but don't force it with an ITE (even in mode all)
131	66	lowerNode(assertion, false);
132	66	Node newAssertion = fromCache(assertion);
133	132	TypeNode newAssertionType = newAssertion.getType();
134	66	if (newAssertionType.isBitVector())
135		{
136	62	Assert(newAssertionType.getBitVectorSize() == 1);
137	124	newAssertion = NodeManager::currentNM()->mkNode(
138	124	kind::EQUAL, newAssertion, bv::utils::mkOne(1));
139	62	newAssertionType = newAssertion.getType();
140		}
141	66	Assert(newAssertionType.isBoolean());
142	132	return newAssertion;
143		}
144
145	172	Node BoolToBV::lowerNode(const TNode& node, bool allowIteIntroduction)
146		{
147	344	std::vector<TNode> to_visit;
148	172	to_visit.push_back(node);
149	344	std::unordered_set<TNode> visited;
150
151	2540	while (!to_visit.empty())
152		{
153	2368	TNode n = to_visit.back();
154	1184	to_visit.pop_back();
155
156	2368	Debug("bool-to-bv") << "BoolToBV::lowerNode: Post-order traversal with "
157	2368	<< n << " and visited = " << ContainsKey(visited, n)
158	1184	<< std::endl;
159
160		// Mark as visited
161	1184	if (ContainsKey(visited, n))
162		{
163	614	visit(n, allowIteIntroduction);
164		}
165		else
166		{
167	570	visited.insert(n);
168	570	to_visit.push_back(n);
169
170		// insert children in reverse order so that they're processed in order
171		// important for rewriting which sorts by node id
172		// NOTE: size_t is unsigned, so using underflow for termination condition
173	570	size_t numChildren = n.getNumChildren();
174	1012	for (size_t i = numChildren - 1; i < numChildren; --i)
175		{
176	442	to_visit.push_back(n[i]);
177		}
178		}
179		}
180
181	344	return fromCache(node);
182		}
183
184	614	void BoolToBV::visit(const TNode& n, bool allowIteIntroduction)
185		{
186	614	Kind k = n.getKind();
187
188		// easy case -- just replace boolean constant
189	614	if (k == kind::CONST_BOOLEAN)
190		{
191	10	updateCache(n,
192	20	(n == bv::utils::mkTrue()) ? bv::utils::mkOne(1)
193		: bv::utils::mkZero(1));
194	132	return;
195		}
196
197	604	NodeManager* nm = NodeManager::currentNM();
198	604	Kind new_kind = k;
199	604	switch (k)
200		{
201	38	case kind::EQUAL: new_kind = kind::BITVECTOR_COMP; break;
202	10	case kind::AND: new_kind = kind::BITVECTOR_AND; break;
203	4	case kind::OR: new_kind = kind::BITVECTOR_OR; break;
204	26	case kind::NOT: new_kind = kind::BITVECTOR_NOT; break;
205	6	case kind::XOR: new_kind = kind::BITVECTOR_XOR; break;
206	20	case kind::IMPLIES: new_kind = kind::BITVECTOR_OR; break;
207	12	case kind::ITE: new_kind = kind::BITVECTOR_ITE; break;
208	16	case kind::BITVECTOR_ULT: new_kind = kind::BITVECTOR_ULTBV; break;
209	4	case kind::BITVECTOR_SLT: new_kind = kind::BITVECTOR_SLTBV; break;
210		case kind::BITVECTOR_ULE:
211		case kind::BITVECTOR_UGT:
212		case kind::BITVECTOR_UGE:
213		case kind::BITVECTOR_SLE:
214		case kind::BITVECTOR_SGT:
215		case kind::BITVECTOR_SGE:
216		// Should have been removed by rewriting.
217		Unreachable();
218	468	default: break;
219		}
220
221		// check if it's safe to lower or rebuild the node
222		// Note: might have to rebuild to keep changes to children, even if this node
223		// isn't being lowered
224
225		// it's safe to lower if all the children are bit-vectors
226	604	bool safe_to_lower =
227	604	(new_kind != k); // don't need to lower at all if kind hasn't changed
228
229		// it's safe to rebuild if rebuilding doesn't change any of the types of the
230		// children
231	604	bool safe_to_rebuild = true;
232
233	998	for (const Node& nn : n)
234		{
235	434	safe_to_lower = safe_to_lower && fromCache(nn).getType().isBitVector();
236	434	safe_to_rebuild = safe_to_rebuild && (fromCache(nn).getType() == nn.getType());
237
238		// if it's already not safe to do either, stop checking
239	434	if (!safe_to_lower && !safe_to_rebuild)
240		{
241	40	break;
242		}
243		}
244
245	1208	Debug("bool-to-bv") << "safe_to_lower = " << safe_to_lower
246	604	<< ", safe_to_rebuild = " << safe_to_rebuild << std::endl;
247
248	604	if (new_kind != k && safe_to_lower)
249		{
250		// lower to BV
251	104	rebuildNode(n, new_kind);
252	104	return;
253		}
254	500	else if (new_kind != k && allowIteIntroduction && fromCache(n).getType().isBoolean())
255		{
256		// lower to BV using an ITE
257
258	8	if (safe_to_rebuild && needToRebuild(n))
259		{
260		// need to rebuild to keep changes made to descendants
261		rebuildNode(n, k);
262		}
263
264	8	updateCache(n,
265	48	nm->mkNode(kind::ITE,
266	16	fromCache(n),
267	16	bv::utils::mkOne(1),
268	16	bv::utils::mkZero(1)));
269	16	Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
270	8	<< " =>\n"
271	8	<< fromCache(n) << std::endl;
272	8	if (d_boolToBVMode == options::BoolToBVMode::ALL)
273		{
274		// this statistic only makes sense for ALL mode
275	8	++(d_statistics.d_numIntroducedItes);
276		}
277	8	return;
278		}
279	492	else if (safe_to_rebuild && needToRebuild(n))
280		{
281		// rebuild to incorporate changes to children
282		Assert(k == new_kind);
283		rebuildNode(n, k);
284		}
285	492	else if (allowIteIntroduction && fromCache(n).getType().isBoolean())
286		{
287		// force booleans (which haven't already been converted) to bit-vector
288		// needed to maintain the invariant that all boolean children
289		// have been converted (even constants and variables) when forcing
290		// with ITE introductions
291	32	updateCache(
292	64	n, nm->mkNode(kind::ITE, n, bv::utils::mkOne(1), bv::utils::mkZero(1)));
293	64	Debug("bool-to-bv") << "BoolToBV::visit forcing " << n
294	32	<< " =>\n"
295	32	<< fromCache(n) << std::endl;
296	32	if (d_boolToBVMode == options::BoolToBVMode::ALL)
297		{
298		// this statistic only makes sense for ALL mode
299	32	++(d_statistics.d_numIntroducedItes);
300		}
301		}
302		else
303		{
304		// do nothing
305	920	Debug("bool-to-bv") << "BoolToBV::visit skipping: " << n
306	460	<< std::endl;
307		}
308		}
309
310	20	Node BoolToBV::lowerIte(const TNode& node)
311		{
312	40	std::vector<TNode> visit;
313	20	visit.push_back(node);
314	40	std::unordered_set<TNode> visited;
315
316	316	while (!visit.empty())
317		{
318	296	TNode n = visit.back();
319	148	visit.pop_back();
320
321	296	Debug("bool-to-bv") << "BoolToBV::lowerIte: Post-order traversal with " << n
322	296	<< " and visited = " << ContainsKey(visited, n)
323	148	<< std::endl;
324
325		// Look for ITEs and mark visited
326	148	if (!ContainsKey(visited, n))
327		{
328	72	if ((n.getKind() == kind::ITE) && n[1].getType().isBitVector())
329		{
330	8	Debug("bool-to-bv") << "BoolToBV::lowerIte: adding " << n[0]
331	4	<< " to set of ite conditions" << std::endl;
332		// don't force in this case -- forcing only introduces more ITEs
333	8	Node loweredNode = lowerNode(n, false);
334		// some of the lowered nodes might appear elsewhere but not in an ITE
335		// reset the cache to prevent lowering them
336		// the bit-vector ITEs are still tracked in d_iteBVLowerCache though
337	4	d_lowerCache.clear();
338		}
339		else
340		{
341	68	visit.push_back(n);
342	68	visited.insert(n);
343		// insert in reverse order so that they're processed in order
344	128	for (int i = n.getNumChildren() - 1; i >= 0; --i)
345		{
346	60	visit.push_back(n[i]);
347		}
348		}
349		}
350	76	else if (needToRebuild(n))
351		{
352		// Note: it's always safe to rebuild here, because we've only lowered
353		// ITEs of type bit-vector to BITVECTOR_ITE
354	4	rebuildNode(n, n.getKind());
355		}
356		else
357		{
358	144	Debug("bool-to-bv")
359	72	<< "BoolToBV::lowerIte Skipping because don't need to rebuild: " << n
360	72	<< std::endl;
361		}
362		}
363	40	return fromCache(node);
364		}
365
366	108	void BoolToBV::rebuildNode(const TNode& n, Kind new_kind)
367		{
368	108	Kind k = n.getKind();
369	108	NodeManager* nm = NodeManager::currentNM();
370	216	NodeBuilder builder(new_kind);
371
372	216	Debug("bool-to-bv") << "BoolToBV::rebuildNode with " << n
373	216	<< " and new_kind = " << kindToString(new_kind)
374	108	<< std::endl;
375
376	108	if ((d_boolToBVMode == options::BoolToBVMode::ALL) && (new_kind != k))
377		{
378		// this statistic only makes sense for ALL mode
379	96	++(d_statistics.d_numTermsLowered);
380		}
381
382	108	if (n.getMetaKind() == kind::metakind::PARAMETERIZED)
383		{
384		builder << n.getOperator();
385		}
386
387		// special case IMPLIES because needs to be rewritten
388	108	if ((k == kind::IMPLIES) && (new_kind != k))
389		{
390	20	builder << nm->mkNode(kind::BITVECTOR_NOT, fromCache(n[0]));
391	20	builder << fromCache(n[1]);
392		}
393		else
394		{
395	250	for (const Node& nn : n)
396		{
397	162	builder << fromCache(nn);
398		}
399		}
400
401	216	Debug("bool-to-bv") << "BoolToBV::rebuildNode " << n << " =>\n"
402	108	<< builder << std::endl;
403
404	108	updateCache(n, builder.constructNode());
405	108	}
406
407	9942	BoolToBV::Statistics::Statistics(StatisticsRegistry& reg)
408		: d_numIteToBvite(
409	19884	reg.registerInt("preprocessing::passes::BoolToBV::NumIteToBvite")),
410		// the following two statistics are not correct in the ITE mode, because
411		// we might discard rebuilt nodes if we fails to convert a bool to
412		// width-one bit-vector (never forces)
413		d_numTermsLowered(
414	19884	reg.registerInt("preprocessing::passes:BoolToBV::NumTermsLowered")),
415		d_numIntroducedItes(reg.registerInt(
416	29826	"preprocessing::passes::BoolToBV::NumTermsForcedLowered"))
417		{
418	9942	}
419
420		} // namespace passes
421		} // namespace preprocessing
422	29577	} // namespace cvc5