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seq rewriting fixes

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-11-22 10:48:49 -08:00
parent 7b2590c026
commit 498fa87993
4 changed files with 184 additions and 142 deletions
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157
src/ast/rewriter/seq_rewriter.cpp
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@ -675,25 +675,17 @@ br_status seq_rewriter::mk_seq_contains(expr* a, expr* b, expr_ref& result) {
result = m().mk_bool_val(c.contains(d));
return BR_DONE;
}
expr* x = nullptr, *y, *z;
if (m_util.str.is_extract(b, x, y, z) && x == a) {
result = m().mk_true();
return BR_DONE;
}
// check if subsequence of a is in b.
expr_ref_vector as(m()), bs(m());
if (m_util.str.is_string(a, c)) {
for (unsigned i = 0; i < c.length(); ++i) {
as.push_back(m_util.str.mk_unit(m_util.str.mk_char(c, i)));
}
}
else {
m_util.str.get_concat(a, as);
}
if (m_util.str.is_string(b, d)) {
for (unsigned i = 0; i < d.length(); ++i) {
bs.push_back(m_util.str.mk_unit(m_util.str.mk_char(d, i)));
}
}
else {
m_util.str.get_concat(b, bs);
}
bool all_values = true;
m_util.str.get_concat_units(a, as);
m_util.str.get_concat_units(b, bs);
TRACE("seq", tout << mk_pp(a, m()) << " contains " << mk_pp(b, m()) << "\n";);
if (bs.empty()) {
@ -701,24 +693,21 @@ br_status seq_rewriter::mk_seq_contains(expr* a, expr* b, expr_ref& result) {
return BR_DONE;
}
for (unsigned i = 0; all_values && i < bs.size(); ++i) {
all_values = m().is_value(bs[i].get());
if (as.empty()) {
result = m().mk_eq(b, m_util.str.mk_empty(m().get_sort(b)));
return BR_REWRITE2;
}
bool found = false;
for (unsigned i = 0; !found && i < as.size(); ++i) {
all_values &= m().is_value(as[i].get());
if (bs.size() <= as.size() - i) {
unsigned j = 0;
for (; j < bs.size() && as[j+i].get() == bs[j].get(); ++j) {};
found = j == bs.size();
for (unsigned i = 0; bs.size() + i <= as.size(); ++i) {
unsigned j = 0;
for (; j < bs.size() && as.get(j+i) == bs.get(j); ++j) {};
if (j == bs.size()) {
result = m().mk_true();
return BR_DONE;
}
}
if (found) {
result = m().mk_true();
return BR_DONE;
}
if (all_values) {
std::function<bool(expr*)> is_value = [&](expr* e) { return m().is_value(e); };
if (bs.forall(is_value) && as.forall(is_value)) {
result = m().mk_false();
return BR_DONE;
}
@ -733,26 +722,12 @@ br_status seq_rewriter::mk_seq_contains(expr* a, expr* b, expr_ref& result) {
}
}
if (as.empty()) {
result = m().mk_eq(b, m_util.str.mk_empty(m().get_sort(b)));
return BR_REWRITE2;
}
if (bs.size() == 1 && m_util.str.is_string(bs[0].get(), c)) {
for (auto a_i : as) {
if (m_util.str.is_string(a_i, d) && d.contains(c)) {
result = m().mk_true();
return BR_DONE;
}
}
}
unsigned offs = 0;
unsigned sz = as.size();
expr* b0 = bs[0].get();
expr* bL = bs[bs.size()-1].get();
expr* b0 = bs.get(0);
expr* bL = bs.get(bs.size()-1);
for (; offs < as.size() && cannot_contain_prefix(as[offs].get(), b0); ++offs) {}
for (; sz > offs && cannot_contain_suffix(as[sz-1].get(), bL); --sz) {}
for (; sz > offs && cannot_contain_suffix(as.get(sz-1), bL); --sz) {}
if (offs == sz) {
result = m().mk_eq(b, m_util.str.mk_empty(m().get_sort(b)));
return BR_REWRITE2;
@ -763,24 +738,15 @@ br_status seq_rewriter::mk_seq_contains(expr* a, expr* b, expr_ref& result) {
return BR_REWRITE2;
}
expr* x, *y, *z;
if (m_util.str.is_extract(b, x, y, z) && x == a) {
result = m().mk_true();
return BR_DONE;
}
std::function<bool(expr*)> is_unit = [&](expr *e) { return m_util.str.is_unit(e); };
if (bs.forall(is_unit) && as.forall(is_unit)) {
if (as.size() < bs.size()) {
result = m().mk_false();
return BR_DONE;
}
expr_ref_vector ors(m());
for (unsigned i = 0; i < as.size() - bs.size() + 1; ++i) {
for (unsigned i = 0; i + bs.size() <= as.size(); ++i) {
expr_ref_vector ands(m());
for (unsigned j = 0; j < bs.size(); ++j) {
ands.push_back(m().mk_eq(as[i + j].get(), bs[j].get()));
ands.push_back(m().mk_eq(as.get(i + j), bs.get(j)));
}
ors.push_back(::mk_and(ands));
}
@ -797,46 +763,41 @@ br_status seq_rewriter::mk_seq_contains(expr* a, expr* b, expr_ref& result) {
br_status seq_rewriter::mk_seq_at(expr* a, expr* b, expr_ref& result) {
zstring c;
rational r;
if (m_autil.is_numeral(b, r)) {
if (r.is_neg()) {
result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE;
}
unsigned len = 0;
bool bounded = min_length(1, &a, len);
if (bounded && r >= rational(len)) {
result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE;
}
if (m_util.str.is_string(a, c)) {
if (r.is_unsigned() && r < rational(c.length())) {
result = m_util.str.mk_string(c.extract(r.get_unsigned(), 1));
}
else {
result = m_util.str.mk_empty(m().get_sort(a));
}
return BR_DONE;
}
if (r.is_unsigned()) {
len = r.get_unsigned();
expr_ref_vector as(m());
m_util.str.get_concat(a, as);
for (unsigned i = 0; i < as.size(); ++i) {
if (m_util.str.is_unit(as[i].get())) {
if (len == 0) {
result = as[i].get();
return BR_DONE;
}
--len;
}
else {
return BR_FAILED;
}
}
}
if (!m_autil.is_numeral(b, r)) {
return BR_FAILED;
}
return BR_FAILED;
if (r.is_neg()) {
result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE;
}
if (!r.is_unsigned()) {
return BR_FAILED;
}
unsigned len = r.get_unsigned();
expr_ref_vector as(m());
m_util.str.get_concat_units(a, as);
for (unsigned i = 0; i < as.size(); ++i) {
expr* a = as.get(i);
if (m_util.str.is_unit(a)) {
if (len == i) {
result = a;
return BR_REWRITE1;
}
}
else if (i > 0) {
SASSERT(len >= i);
result = m_util.str.mk_concat(as.size() - i, as.c_ptr() + i);
result = m().mk_app(m_util.get_family_id(), OP_SEQ_AT, result, m_autil.mk_int(len - i));
return BR_REWRITE2;
}
else {
return BR_FAILED;
}
}
result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE;
}
br_status seq_rewriter::mk_seq_index(expr* a, expr* b, expr* c, expr_ref& result) {