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change data-structures to concanetation decomposition normal form

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-01-07 16:03:37 -08:00
parent 0c2334417c
commit ad778f87c7
6 changed files with 235 additions and 401 deletions
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118
src/ast/rewriter/seq_rewriter.cpp
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@ -830,11 +830,12 @@ br_status seq_rewriter::mk_re_opt(expr* a, expr_ref& result) {
br_status seq_rewriter::mk_eq_core(expr * l, expr * r, expr_ref & result) {
expr_ref_vector lhs(m()), rhs(m()), res(m());
if (!reduce_eq(l, r, lhs, rhs)) {
bool changed = false;
if (!reduce_eq(l, r, lhs, rhs, changed)) {
result = m().mk_false();
return BR_DONE;
}
if (lhs.size() == 1 && lhs[0].get() == l && rhs[0].get() == r) {
if (!changed) {
return BR_FAILED;
}
for (unsigned i = 0; i < lhs.size(); ++i) {
@ -844,20 +845,19 @@ br_status seq_rewriter::mk_eq_core(expr * l, expr * r, expr_ref & result) {
return BR_REWRITE3;
}
bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_vector& lhs, expr_ref_vector& rhs) {
bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_vector& lhs, expr_ref_vector& rhs, bool& change) {
expr* a, *b;
zstring s;
bool change = false;
bool lchange = false;
SASSERT(lhs.empty());
// solve from back
while (true) {
while (!rs.empty() && m_util.str.is_empty(rs.back())) {
rs.pop_back();
change = true;
}
while (!ls.empty() && m_util.str.is_empty(ls.back())) {
ls.pop_back();
change = true;
}
if (ls.empty() || rs.empty()) {
break;
@ -901,7 +901,9 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
else {
break;
}
TRACE("seq", tout << "change back\n";);
change = true;
lchange = true;
}
// solve from front
@ -956,7 +958,10 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
else {
break;
}
TRACE("seq", tout << "change front\n";);
change = true;
lchange = true;
}
// reduce strings
zstring s1, s2;
@ -982,7 +987,9 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
else {
rs[head2] = m_util.str.mk_string(s2.extract(l, s2.length()-l));
}
TRACE("seq", tout << "change string\n";);
change = true;
lchange = true;
}
while (head1 < ls.size() &&
head2 < rs.size() &&
@ -1002,52 +1009,109 @@ bool seq_rewriter::reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_
if (l < s2.length()) {
rs.push_back(m_util.str.mk_string(s2.extract(0, s2.length()-l)));
}
TRACE("seq", tout << "change string back\n";);
change = true;
lchange = true;
}
bool is_sat;
unsigned szl = ls.size() - head1, szr = rs.size() - head2;
expr* const* _ls = ls.c_ptr() + head1, * const* _rs = rs.c_ptr() + head2;
if (length_constrained(szl, _ls, szr, _rs, lhs, rhs, is_sat)) {
ls.reset(); rs.reset();
return is_sat;
}
if (is_subsequence(szl, _ls, szr, _rs, lhs, rhs, is_sat)) {
ls.reset(); rs.reset();
change = true;
return is_sat;
}
if (szl == 0 && szr == 0) {
ls.reset(); rs.reset();
return true;
}
else if (!change) {
// skip
SASSERT(lhs.empty());
}
else {
// could solve if either side is fixed size.
SASSERT(szl > 0 && szr > 0);
lhs.push_back(m_util.str.mk_concat(szl, ls.c_ptr() + head1));
rhs.push_back(m_util.str.mk_concat(szr, rs.c_ptr() + head2));
if (szr == 0 && szl == 0) {
ls.reset();
rs.reset();
return true;
}
SASSERT(lhs.empty() || ls.empty());
if (szr == 0 && szl > 0) {
std::swap(szr, szl);
std::swap(_ls, _rs);
}
if (szl == 0 && szr > 0) {
if (set_empty(szr, _rs, true, lhs, rhs)) {
lchange |= szr > 1;
change |= szr > 1;
TRACE("seq", tout << lchange << " " << szr << "\n";);
if (szr == 1 && !lchange) {
lhs.reset();
rhs.reset();
}
else {
ls.reset();
rs.reset();
}
return true;
}
else {
return false;
}
}
SASSERT(szl > 0 && szr > 0);
if (is_subsequence(szl, _ls, szr, _rs, lhs, rhs, is_sat)) {
ls.reset(); rs.reset();
change = true;
return is_sat;
}
if (lchange) {
if (head1 > 0) {
for (unsigned i = 0; i < szl; ++i) {
ls[i] = ls[i + head1];
}
}
ls.shrink(szl);
if (head2 > 0) {
for (unsigned i = 0; i < szr; ++i) {
rs[i] = rs[i + head2];
}
}
rs.shrink(szr);
}
SASSERT(rs.empty() == ls.empty());
change |= lchange;
return true;
}
bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs) {
void seq_rewriter::add_seqs(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref_vector& lhs, expr_ref_vector& rhs) {
if (ls.empty() && !rs.empty()) {
rhs.push_back(m_util.str.mk_concat(rs));
lhs.push_back(m_util.str.mk_empty(m().get_sort(rhs.back())));
}
else if (rs.empty() && !ls.empty()) {
lhs.push_back(m_util.str.mk_concat(ls));
rhs.push_back(m_util.str.mk_empty(m().get_sort(lhs.back())));
}
else if (!rs.empty() && !ls.empty()) {
lhs.push_back(m_util.str.mk_concat(ls));
rhs.push_back(m_util.str.mk_concat(rs));
}
}
bool seq_rewriter::reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs, bool& changed) {
m_lhs.reset();
m_rhs.reset();
m_util.str.get_concat(l, m_lhs);
m_util.str.get_concat(r, m_rhs);
if (reduce_eq(m_lhs, m_rhs, lhs, rhs)) {
bool change = false;
if (reduce_eq(m_lhs, m_rhs, lhs, rhs, change)) {
SASSERT(lhs.size() == rhs.size());
if (lhs.empty()) {
if (!change) {
lhs.push_back(l);
rhs.push_back(r);
}
else {
add_seqs(m_lhs, m_rhs, lhs, rhs);
}
changed |= change;
return true;
}
else {