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skip non-overlap simplification in rewriter

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-05-29 17:27:54 -07:00
parent e68c72755a
commit d41ecda03e
3 changed files with 35 additions and 7 deletions
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30
src/ast/rewriter/seq_rewriter.cpp
View file

@ -706,9 +706,6 @@ br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * con
if (st == BR_FAILED) {
st = lift_ite(f, num_args, args, result);
}
if (st != BR_FAILED && m().get_sort(result) != f->get_range()) {
std::cout << expr_ref(m().mk_app(f, num_args, args), m()) << " -> " << result << "\n";
}
CTRACE("seq_verbose", st != BR_FAILED, tout << expr_ref(m().mk_app(f, num_args, args), m()) << " -> " << result << "\n";);
SASSERT(st == BR_FAILED || m().get_sort(result) == f->get_range());
return st;
@ -2604,7 +2601,7 @@ br_status seq_rewriter::mk_str_in_regexp(expr* a, expr* b, expr_ref& result) {
return BR_REWRITE_FULL;
}
if (rewrite_contains_pattern(a, b, result))
if (false && rewrite_contains_pattern(a, b, result))
return BR_REWRITE_FULL;
return BR_FAILED;
@ -3463,6 +3460,8 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
reduce_itos(rs, ls, eqs) &&
reduce_by_length(ls, rs, eqs) &&
reduce_subsequence(ls, rs, eqs) &&
reduce_non_overlap(ls, rs, eqs) &&
reduce_non_overlap(rs, ls, eqs) &&
(change = (hash_l != ls.hash() || hash_r != rs.hash() || eqs.size() != sz_eqs),
true);
}
@ -3689,6 +3688,29 @@ bool seq_rewriter::is_epsilon(expr* e) const {
return re().is_to_re(e, e1) && str().is_empty(e1);
}
/**
reduce for the case where rs = a constant string,
ls contains a substring that matches no substring of rs.
*/
bool seq_rewriter::reduce_non_overlap(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs) {
for (expr* u : rs)
if (!str().is_unit(u))
return true;
expr_ref_vector pattern(m());
for (expr* x : ls) {
if (str().is_unit(x))
pattern.push_back(x);
else if (!pattern.empty()) {
if (non_overlap(pattern, rs))
return false;
pattern.reset();
}
}
if (!pattern.empty() && non_overlap(pattern, rs))
return false;
return true;
}
bool seq_rewriter::reduce_subsequence(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs) {
if (ls.size() > rs.size())

1
src/ast/rewriter/seq_rewriter.h
View file

@ -199,6 +199,7 @@ class seq_rewriter {
bool sign_is_determined(expr* len, sign& s);
bool set_empty(unsigned sz, expr* const* es, bool all, expr_ref_pair_vector& eqs);
bool reduce_non_overlap(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs);
bool reduce_subsequence(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs);
bool reduce_by_length(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs);
bool reduce_itos(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_pair_vector& eqs);

11
src/smt/seq_regex.cpp
View file

@ -63,16 +63,21 @@ namespace smt {
bool seq_regex::is_string_equality(literal lit) {
expr* s = nullptr, *r = nullptr;
expr* e = ctx.bool_var2expr(lit.var());
expr_ref id(a().mk_int(e->get_id()), m);
unsigned idx = 0;
VERIFY(str().is_in_re(e, s, r));
sort* seq_sort = m.get_sort(s);
vector<expr_ref_vector> patterns;
auto mk_cont = [&](unsigned idx) {
return sk().mk("seq.cont", id, a().mk_int(idx), seq_sort);
};
if (seq_rw().is_re_contains_pattern(r, patterns)) {
expr_ref t(m);
expr_ref_vector ts(m);
sort* seq_sort = m.get_sort(s);
ts.push_back(m.mk_fresh_const("seq.cont", seq_sort));
ts.push_back(mk_cont(idx));
for (auto const& p : patterns) {
ts.append(p);
ts.push_back(m.mk_fresh_const("seq.cont", seq_sort));
ts.push_back(mk_cont(idx));
}
t = th.mk_concat(ts, seq_sort);
th.propagate_eq(lit, s, t, true);