From f4f1c63abb4a6fd0df908e376b0ab014bce3d9da Mon Sep 17 00:00:00 2001 From: Leonardo de Moura Date: Thu, 6 Jun 2013 13:20:43 -0700 Subject: [PATCH] Fix issue https://z3.codeplex.com/workitem/38 Signed-off-by: Leonardo de Moura --- src/sat/sat_clause_use_list.h | 20 +++++++++++++++++--- src/sat/sat_simplifier.cpp | 27 +++++++++++++++++---------- src/sat/sat_simplifier.h | 4 ++-- 3 files changed, 36 insertions(+), 15 deletions(-) diff --git a/src/sat/sat_clause_use_list.h b/src/sat/sat_clause_use_list.h index ccf4b4a5b..0859439d5 100644 --- a/src/sat/sat_clause_use_list.h +++ b/src/sat/sat_clause_use_list.h @@ -20,6 +20,7 @@ Revision History: #define _SAT_CLAUSE_USE_LIST_H_ #include"sat_types.h" +#include"trace.h" namespace sat { @@ -35,6 +36,7 @@ namespace sat { #endif public: clause_use_list() { + STRACE("clause_use_list_bug", tout << "[cul_created] " << this << "\n";); #ifdef LAZY_USE_LIST m_size = 0; #endif @@ -51,22 +53,33 @@ namespace sat { bool empty() const { return size() == 0; } void insert(clause & c) { - SASSERT(!m_clauses.contains(&c)); SASSERT(!c.was_removed()); + STRACE("clause_use_list_bug", tout << "[cul_insert] " << this << " " << &c << "\n";); + SASSERT(!m_clauses.contains(&c)); + SASSERT(!c.was_removed()); m_clauses.push_back(&c); #ifdef LAZY_USE_LIST m_size++; #endif } + void erase_not_removed(clause & c) { + STRACE("clause_use_list_bug", tout << "[cul_erase_not_removed] " << this << " " << &c << "\n";); #ifdef LAZY_USE_LIST - SASSERT(m_clauses.contains(&c)); SASSERT(!c.was_removed()); m_clauses.erase(&c); m_size--; + SASSERT(m_clauses.contains(&c)); + SASSERT(!c.was_removed()); + m_clauses.erase(&c); + m_size--; #else m_clauses.erase(&c); #endif } + void erase(clause & c) { + STRACE("clause_use_list_bug", tout << "[cul_erase] " << this << " " << &c << "\n";); #ifdef LAZY_USE_LIST - SASSERT(m_clauses.contains(&c)); SASSERT(c.was_removed()); m_size--; + SASSERT(m_clauses.contains(&c)); + SASSERT(c.was_removed()); + m_size--; #else m_clauses.erase(&c); #endif @@ -80,6 +93,7 @@ namespace sat { } bool check_invariant() const; + // iterate & compress class iterator { clause_vector & m_clauses; diff --git a/src/sat/sat_simplifier.cpp b/src/sat/sat_simplifier.cpp index 623c73758..51006b2c9 100644 --- a/src/sat/sat_simplifier.cpp +++ b/src/sat/sat_simplifier.cpp @@ -146,8 +146,11 @@ namespace sat { m_need_cleanup = false; m_use_list.init(s.num_vars()); init_visited(); - if (learned) + bool learned_in_use_lists = false; + if (learned) { register_clauses(s.m_learned); + learned_in_use_lists = true; + } register_clauses(s.m_clauses); if (!learned && (m_elim_blocked_clauses || m_elim_blocked_clauses_at == m_num_calls)) @@ -179,7 +182,7 @@ namespace sat { if (!m_need_cleanup) { if (vars_eliminated) { // must remove learned clauses with eliminated variables - cleanup_clauses(s.m_learned, true, true); + cleanup_clauses(s.m_learned, true, true, learned_in_use_lists); } CASSERT("sat_solver", s.check_invariant()); TRACE("after_simplifier", s.display(tout); tout << "model_converter:\n"; s.m_mc.display(tout);); @@ -187,8 +190,8 @@ namespace sat { return; } cleanup_watches(); - cleanup_clauses(s.m_learned, true, vars_eliminated); - cleanup_clauses(s.m_clauses, false, vars_eliminated); + cleanup_clauses(s.m_learned, true, vars_eliminated, learned_in_use_lists); + cleanup_clauses(s.m_clauses, false, vars_eliminated, true); TRACE("after_simplifier", s.display(tout); tout << "model_converter:\n"; s.m_mc.display(tout);); CASSERT("sat_solver", s.check_invariant()); free_memory(); @@ -221,7 +224,7 @@ namespace sat { } } - void simplifier::cleanup_clauses(clause_vector & cs, bool learned, bool vars_eliminated) { + void simplifier::cleanup_clauses(clause_vector & cs, bool learned, bool vars_eliminated, bool in_use_lists) { clause_vector::iterator it = cs.begin(); clause_vector::iterator it2 = it; clause_vector::iterator end = cs.end(); @@ -245,7 +248,7 @@ namespace sat { } } - if (cleanup_clause(c)) { + if (cleanup_clause(c, in_use_lists)) { s.del_clause(c); continue; } @@ -516,7 +519,7 @@ namespace sat { Return true if the clause is satisfied */ - bool simplifier::cleanup_clause(clause & c) { + bool simplifier::cleanup_clause(clause & c, bool in_use_list) { bool r = false; unsigned sz = c.size(); unsigned j = 0; @@ -529,7 +532,11 @@ namespace sat { break; case l_false: m_need_cleanup = true; - m_use_list.get(l).erase_not_removed(c); + if (in_use_list && !c.frozen()) { + // Remark: if in_use_list is false, then the given clause was not added to the use lists. + // Remark: frozen clauses are not added to the use lists. + m_use_list.get(l).erase_not_removed(c); + } break; case l_true: r = true; @@ -611,7 +618,7 @@ namespace sat { clause_use_list & occurs = m_use_list.get(l); occurs.erase_not_removed(c); m_sub_counter -= occurs.size()/2; - if (cleanup_clause(c)) { + if (cleanup_clause(c, true /* clause is in the use lists */)) { // clause was satisfied TRACE("elim_lit", tout << "clause was satisfied\n";); remove_clause(c); @@ -805,7 +812,7 @@ namespace sat { m_sub_counter--; TRACE("subsumption", tout << "next: " << c << "\n";); if (s.m_trail.size() > m_last_sub_trail_sz) { - if (cleanup_clause(c)) { + if (cleanup_clause(c, true /* clause is in the use_lists */)) { remove_clause(c); continue; } diff --git a/src/sat/sat_simplifier.h b/src/sat/sat_simplifier.h index 44e2f0dee..96d346598 100644 --- a/src/sat/sat_simplifier.h +++ b/src/sat/sat_simplifier.h @@ -125,7 +125,7 @@ namespace sat { void collect_subsumed0(clause const & c1, clause_vector & out); void back_subsumption0(clause & c1); - bool cleanup_clause(clause & c); + bool cleanup_clause(clause & c, bool in_use_list); bool cleanup_clause(literal_vector & c); void propagate_unit(literal l); void elim_lit(clause & c, literal l); @@ -136,7 +136,7 @@ namespace sat { void subsume(); void cleanup_watches(); - void cleanup_clauses(clause_vector & cs, bool learned, bool vars_eliminated); + void cleanup_clauses(clause_vector & cs, bool learned, bool vars_eliminated, bool in_use_lists); bool is_external(bool_var v) const; bool was_eliminated(bool_var v) const;