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fix #1694

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-06-20 17:35:41 -07:00
parent 8241ba784d
commit 19e2f8c9d5
3 changed files with 48 additions and 18 deletions
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33
src/tactic/core/tseitin_cnf_tactic.cpp
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@ -466,6 +466,38 @@ class tseitin_cnf_tactic : public tactic {
}
return NO;
}
mres match_iff_or(app * t, bool first, bool root) {
expr * a = nullptr, * _b = nullptr;
if (!root) return NO;
if (!is_iff(m, t, a, _b)) return NO;
bool sign = m.is_not(_b, _b);
if (!m.is_or(_b)) return NO;
app* b = to_app(_b);
unsigned num = b->get_num_args();
if (first) {
bool visited = true;
visit(a, visited);
for (expr* arg : *b) {
visit(arg, visited);
}
if (!visited)
return CONT;
}
expr_ref la(m), nla(m), nlb(m), lb(m);
get_lit(a, sign, la);
inv(la, nla);
expr_ref_buffer lits(m);
lits.push_back(nla);
for (expr* arg : *b) {
get_lit(arg, false, lb);
lits.push_back(lb);
inv(lb, nlb);
mk_clause(la, nlb);
}
mk_clause(lits.size(), lits.c_ptr());
return DONE;
}
mres match_iff(app * t, bool first, bool root) {
expr * a, * b;
@ -784,6 +816,7 @@ class tseitin_cnf_tactic : public tactic {
TRY(match_or_3and);
TRY(match_or);
TRY(match_iff3);
// TRY(match_iff_or);
TRY(match_iff);
TRY(match_ite);
TRY(match_not);