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fixes related to #6577

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- enforce elim-and in bool-rewriter when invoking hoisting.
- make cnf tactic more resilient to non-normalized input.
- enable eliminate predicates on ground formulas
This commit is contained in:
Nikolaj Bjorner 2023-02-12 13:43:44 -08:00
parent ede9e5ffc2
commit cac5052685
5 changed files with 69 additions and 8 deletions
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41
src/tactic/core/tseitin_cnf_tactic.cpp
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@ -141,6 +141,7 @@ class tseitin_cnf_tactic : public tactic {
sign = !sign;
goto start;
case OP_OR:
case OP_AND:
l = nullptr;
m_cache.find(to_app(n), l);
SASSERT(l != 0);
@ -187,6 +188,7 @@ class tseitin_cnf_tactic : public tactic {
goto start;
}
case OP_OR:
case OP_AND:
visited = false;
push_frame(to_app(n));
return;
@ -197,7 +199,6 @@ class tseitin_cnf_tactic : public tactic {
push_frame(to_app(n));
}
return;
case OP_AND:
case OP_XOR:
case OP_IMPLIES:
case OP_DISTINCT:
@ -617,6 +618,43 @@ class tseitin_cnf_tactic : public tactic {
}
return DONE;
}
mres match_and(app * t, bool first, bool root) {
if (!m.is_and(t))
return NO;
if (first) {
bool visited = true;
for (expr* a : *t)
visit(a, visited);
if (!visited)
return CONT;
}
expr_ref_buffer lits(m);
expr_ref l(m), nl(m);
app_ref k(m), nk(m);
if (root) {
for (expr* arg : *t) {
get_lit(arg, false, l);
expr* lits[1] = { l };
mk_clause(1, lits);
}
}
else {
k = mk_fresh();
nk = m.mk_not(k);
cache_result(t, k);
for (expr* arg : *t) {
get_lit(arg, false, l);
mk_clause(nk, l);
inv(l, nl);
lits.push_back(nl);
}
lits.push_back(k);
mk_clause(lits.size(), lits.data());
}
return DONE;
}
mres match_or(app * t, bool first, bool root) {
if (!m.is_or(t))
@ -778,6 +816,7 @@ class tseitin_cnf_tactic : public tactic {
fr.m_first = false;
TRY(match_or_3and);
TRY(match_or);
TRY(match_and);
TRY(match_iff3);
// TRY(match_iff_or);
TRY(match_iff);