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Bugfix seq-eq sls (#7495)

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* Fixed spurious counterexamples in seq-sls. Updates might not be identity mapping

* Removed debug code

* One check was missing
This commit is contained in:
Clemens Eisenhofer 2024-12-27 17:40:34 +01:00 • committed by GitHub
parent 5eb71c3be6
commit 8de0005ab3
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GPG key ID: B5690EEEBB952194
2 changed files with 32 additions and 14 deletions
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44
src/ast/sls/sls_seq_plugin.cpp
View file

@ -114,10 +114,10 @@ namespace sls {
auto e = ctx.atom(lit.var());
if (!is_seq_predicate(e))
return;
auto a = to_app(e);
if (bval1(e) != lit.sign())
return;
ctx.new_value_eh(e);
// Literal not currently satisfied => report back to context
ctx.new_value_eh(e);
}
expr_ref seq_plugin::get_value(expr* e) {
@ -265,6 +265,7 @@ namespace sls {
return e.rhs;
}
// Gets the currently assumed value for e
zstring& seq_plugin::strval0(expr* e) {
SASSERT(seq.is_string(e->get_sort()));
return get_eval(e).val0.svalue;
@ -343,8 +344,8 @@ namespace sls {
return false;
}
// Evaluate e using the assumed values of its arguments and cache + return the result
zstring const& seq_plugin::strval1(expr* e) {
SASSERT(is_app(e));
SASSERT(seq.is_string(e->get_sort()));
auto & ev = get_eval(e);
if (ev.is_value)
@ -608,6 +609,7 @@ namespace sls {
VERIFY(m.is_eq(e, x, y));
IF_VERBOSE(3, verbose_stream() << is_true << ": " << mk_bounded_pp(e, m, 3) << "\n");
if (ctx.is_true(e)) {
// equality
if (false && ctx.rand(2) != 0 && repair_down_str_eq_edit_distance_incremental(e))
return true;
if (ctx.rand(2) != 0 && repair_down_str_eq_edit_distance(e))
@ -620,6 +622,7 @@ namespace sls {
m_str_updates.push_back({ y, strval1(x), 1 });
}
else {
// disequality
if (!is_value(x) && !m_chars.empty()) {
zstring ch(m_chars[ctx.rand(m_chars.size())]);
m_str_updates.push_back({ x, strval1(y) + ch, 1 });
@ -672,15 +675,28 @@ namespace sls {
m_str_updates.push_back({ x, a + zstring(ch), 1 });
for (auto ch : chars)
m_str_updates.push_back({ x, zstring(ch) + a, 1 });
if (a.length() > 0) {
if (!a.empty()) {
zstring b = a.extract(0, a.length() - 1);
unsigned remC = a[a.length() - 1];
m_str_updates.push_back({ x, b, 1 }); // truncate a
for (auto ch : chars)
for (auto ch : chars) {
if (ch == remC)
// We would end up with the initial string
// => this "no-op" could be spuriously considered a solution (also it does not help)
continue;
m_str_updates.push_back({ x, b + zstring(ch), 1 }); // replace last character in a by ch
b = a.extract(1, a.length() - 1);
m_str_updates.push_back({ x, b, 1 }); // truncate a
for (auto ch : chars)
m_str_updates.push_back({ x, zstring(ch) + b, 1 }); // replace first character in a by ch
}
if (a.length() > 1) {
// Otw. we just get the same set of candidates another time
b = a.extract(1, a.length() - 1);
remC = a[0];
m_str_updates.push_back({ x, b, 1 }); // truncate a
for (auto ch : chars) {
if (ch == remC)
continue;
m_str_updates.push_back({ x, zstring(ch) + b, 1 }); // replace first character in a by ch
}
}
}
}
unsigned first_diff = UINT_MAX;
@ -699,7 +715,8 @@ namespace sls {
if (is_value(x))
break;
auto new_val = val_x.extract(0, first_diff) + zstring(val_other[first_diff]) + val_x.extract(first_diff + 1, val_x.length());
m_str_updates.push_back({ x, new_val, 1 });
if (val_x != new_val)
m_str_updates.push_back({ x, new_val, 1 });
break;
}
index -= len_x;
@ -1468,7 +1485,7 @@ namespace sls {
uint_set chars;
for (auto ch : value0)
chars.insert(ch);
chars.insert(ch);
add_edit_updates(es, value, value0, chars);
@ -1606,8 +1623,9 @@ namespace sls {
}
bool seq_plugin::update(expr* e, zstring const& value) {
if (value == strval0(e))
return true;
SASSERT(value != strval0(e));
// if (value == strval0(e))
// return true;
if (is_value(e))
return false;
if (get_eval(e).min_length > value.length() || get_eval(e).max_length < value.length())

2
src/ast/sls/sls_seq_plugin.h
View file

@ -47,7 +47,7 @@ namespace sls {
seq_rewriter rw;
th_rewriter thrw;
scoped_ptr_vector<eval> m_values;
indexed_uint_set m_chars;
indexed_uint_set m_chars; // set of characters in the problem
bool m_initialized = false;
struct str_update {