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Lookahead for regex splits applied to membership constraints

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Rewriting constraint/prefix/suffix with constant strings to regexes
This commit is contained in:
CEisenhofer 2026-06-10 20:35:36 +02:00
parent f9f16550e0
commit 2dbefbcd56
7 changed files with 220 additions and 69 deletions
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52
src/smt/theory_nseq.cpp
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@ -287,13 +287,13 @@ namespace smt {
void theory_nseq::assign_eh(bool_var v, bool is_true) {
try {
expr* e = ctx.bool_var2expr(v);
//std::cout << "assigned [" << sat::literal(v, !is_true) << "] " << mk_pp(e, m) << " = " << is_true << std::endl;
const literal lit(v, !is_true);
//std::cout << "assigned [" << lit << "] " << mk_pp(e, m) << " = " << is_true << std::endl;
expr *s = nullptr, *re = nullptr, *a = nullptr, *b = nullptr;
TRACE(seq, tout << (is_true ? "" : "¬") << mk_bounded_pp(e, m, 3) << "\n";);
if (m_seq.str.is_in_re(e, s, re)) {
euf::snode* sn_str = get_snode(s);
euf::snode* sn_re = get_snode(re);
const literal lit(v, !is_true);
const seq::dep_tracker dep = nullptr;
if (is_true) {
ctx.push_trail(restore_vector(m_prop_queue));
@ -314,18 +314,63 @@ namespace smt {
}
}
else if (m_seq.str.is_prefix(e)) {
zstring str;
if (m_seq.str.is_string(to_app(e)->get_arg(0), str)) {
// prefix(u, v) with u const => v \in u \Sigma^*
const expr_ref pre(m_seq.re.mk_in_re(to_app(e)->get_arg(1), m_seq.re.mk_concat(
m_seq.re.mk_to_re(to_app(e)->get_arg(0)),
m_seq.re.mk_full_seq(m_seq.re.mk_re(to_app(e)->get_arg(0)->get_sort()))
)), m);
ctx.internalize(pre, false);
literal l = ctx.get_literal(pre);
if (!is_true)
l = ~l;
ctx.mk_th_axiom(get_id(), ~lit, l);
return;
}
if (is_true)
m_axioms.prefix_true_axiom(e);
else
m_axioms.prefix_axiom(e);
}
else if (m_seq.str.is_suffix(e)) {
zstring str;
if (m_seq.str.is_string(to_app(e)->get_arg(0), str)) {
// suffix(u, v) with u const => v \in \Sigma* u
const expr_ref suff(m_seq.re.mk_in_re(to_app(e)->get_arg(1), m_seq.re.mk_concat(
m_seq.re.mk_full_seq(m_seq.re.mk_re(to_app(e)->get_arg(0)->get_sort())),
m_seq.re.mk_to_re(to_app(e)->get_arg(0))
)), m);
ctx.internalize(suff, false);
literal l = ctx.get_literal(suff);
if (!is_true)
l = ~l;
ctx.mk_th_axiom(get_id(), ~lit, l);
return;
}
if (is_true)
m_axioms.suffix_true_axiom(e);
else
m_axioms.suffix_axiom(e);
}
else if (m_seq.str.is_contains(e)) {
zstring str;
if (m_seq.str.is_string(to_app(e)->get_arg(1), str)) {
// contains(u, v) with v const => u \in \Sigma* v \Sigma^*
sort* re_sort = m_seq.re.mk_re(to_app(e)->get_arg(0)->get_sort());
expr* all = m_seq.re.mk_full_seq(re_sort);
const expr_ref con(m_seq.re.mk_in_re(to_app(e)->get_arg(0), m_seq.re.mk_concat(
all,
m_seq.re.mk_concat(
m_seq.re.mk_to_re(to_app(e)->get_arg(1)), all)
)), m);
ctx.internalize(con, false);
literal l = ctx.get_literal(con);
if (!is_true)
l = ~l;
ctx.mk_th_axiom(get_id(), ~lit, l);
return;
}
if (is_true)
m_axioms.contains_true_axiom(e);
else
@ -457,7 +502,7 @@ namespace smt {
expr* const re = mem.m_regex->get_expr();
expr* const s = mem.m_str->get_expr();
// std::cout << "Propagating: " << seq::mem_pp(mem, m) << std::endl;
std::cout << "Propagating: " << seq::mem_pp(mem, m) << std::endl;
if (!mem.m_str->is_empty()) {
if (mem.m_str->first()->is_char()) {
@ -721,7 +766,6 @@ namespace smt {
}
else if (std::holds_alternative<mem_item>(item)) {
auto const& mem = std::get<mem_item>(item);
std::cout << "Adding " << seq::mem_pp(mem, m) << std::endl;
int triv = m_regex.check_trivial(mem);
if (triv > 0) {
++num_mems;