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fix #2618

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-10-06 19:44:33 -07:00
parent 7c10fb83a0
commit a8e7074ddd
2 changed files with 33 additions and 28 deletions
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51
src/ast/rewriter/seq_rewriter.cpp
View file

@ -981,20 +981,18 @@ 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) { br_status seq_rewriter::mk_seq_at(expr* a, expr* b, expr_ref& result) {
zstring c; zstring c;
rational r; rational r;
if (!m_autil.is_numeral(b, r)) { expr_ref_vector lens(m());
if (!get_lengths(b, lens, r)) {
return BR_FAILED; return BR_FAILED;
} }
if (r.is_neg()) { if (lens.empty() && r.is_neg()) {
result = m_util.str.mk_empty(m().get_sort(a)); result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE; return BR_DONE;
} }
if (!r.is_unsigned()) {
return BR_FAILED;
}
unsigned len = r.get_unsigned();
expr* a2 = nullptr, *i2 = nullptr; expr* a2 = nullptr, *i2 = nullptr;
if (m_util.str.is_at(a, a2, i2)) { if (lens.empty() && m_util.str.is_at(a, a2, i2)) {
if (len > 0) { if (r.is_pos()) {
result = m_util.str.mk_empty(m().get_sort(a)); result = m_util.str.mk_empty(m().get_sort(a));
} }
else { else {
@ -1003,30 +1001,37 @@ br_status seq_rewriter::mk_seq_at(expr* a, expr* b, expr_ref& result) {
return BR_DONE; return BR_DONE;
} }
expr_ref_vector as(m()); m_lhs.reset();
m_util.str.get_concat_units(a, as); m_util.str.get_concat_units(a, m_lhs);
for (unsigned i = 0; i < as.size(); ++i) { unsigned i = 0;
expr* a = as.get(i); for (; i < m_lhs.size(); ++i) {
if (m_util.str.is_unit(a)) { expr* lhs = m_lhs.get(i);
if (len == i) { if (lens.contains(lhs)) {
result = a; lens.erase(lhs);
return BR_REWRITE1;
} }
} else if (m_util.str.is_unit(lhs) && r.is_pos()) {
else if (i > 0) { r -= rational(1);
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 { else {
break;
}
}
if (i == 0) {
return BR_FAILED; return BR_FAILED;
} }
} if (m_lhs.size() == i) {
result = m_util.str.mk_empty(m().get_sort(a)); result = m_util.str.mk_empty(m().get_sort(a));
return BR_DONE; return BR_DONE;
} }
expr_ref pos(m_autil.mk_int(r), m());
for (expr* rhs : lens) {
pos = m_autil.mk_add(pos, m_util.str.mk_length(rhs));
}
result = m_util.str.mk_concat(m_lhs.size() - i , m_lhs.c_ptr() + i);
result = m_util.str.mk_at(result, pos);
return BR_REWRITE2;
}
br_status seq_rewriter::mk_seq_nth(expr* a, expr* b, expr_ref& result) { br_status seq_rewriter::mk_seq_nth(expr* a, expr* b, expr_ref& result) {

2
src/smt/theory_seq.cpp
View file

@ -3702,7 +3702,7 @@ void theory_seq::add_stoi_axiom(expr* e) {
add_axiom(l); add_axiom(l);
// stoi("") = -1 // stoi("") = -1
add_axiom(mk_eq(m_util.str.mk_stoi(m_util.str.mk_empty(m.get_sort(s))), m_autil.mk_int(-1), false)); add_axiom(~mk_literal(m_util.str.mk_is_empty(s)), mk_eq(m_util.str.mk_stoi(s), m_autil.mk_int(-1), false));
} }
void theory_seq::add_itos_axiom(expr* e) { void theory_seq::add_itos_axiom(expr* e) {