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Added rewrite cycle detection in demodulator/ufbv_rewriter. Partial fix for #1456.

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This commit is contained in:
Christoph M. Wintersteiger 2018-01-25 15:18:05 +00:00
parent 450f3c9b45
commit 305212c021
1 changed files with 23 additions and 3 deletions
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26
src/tactic/ufbv/ufbv_rewriter.cpp
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@ -322,8 +322,27 @@ bool ufbv_rewriter::rewrite_visit_children(app * a) {
while (j > 0) {
expr * e = a->get_arg(--j);
if (!m_rewrite_cache.contains(e) || !m_rewrite_cache.get(e).second) {
m_rewrite_todo.push_back(e);
res = false;
bool recursive = false;
unsigned sz = m_rewrite_todo.size();
expr * v = e;
if (m_rewrite_cache.contains(e)) {
expr_bool_pair const & ebp = m_rewrite_cache.get(e);
if (ebp.second)
v = ebp.first;
}
for (unsigned i = sz; i > 0; i--) {
if (m_rewrite_todo[i - 1] == v) {
recursive = true;
TRACE("demodulator", tout << "Detected demodulator cycle: " <<
mk_pp(a, m_manager) << " --> " << mk_pp(v, m_manager) << std::endl;);
m_rewrite_cache.insert(e, expr_bool_pair(v, true));
break;
}
}
if (!recursive) {
m_rewrite_todo.push_back(e);
res = false;
}
}
}
return res;
@ -347,7 +366,8 @@ expr * ufbv_rewriter::rewrite(expr * n) {
while (!m_rewrite_todo.empty()) {
TRACE("demodulator_stack", tout << "STACK: " << std::endl;
for ( unsigned i = 0; i<m_rewrite_todo.size(); i++)
tout << std::dec << i << ": " << std::hex << (size_t)m_rewrite_todo[i] << std::endl;
tout << std::dec << i << ": " << std::hex << (size_t)m_rewrite_todo[i] <<
" = " << mk_pp(m_rewrite_todo[i], m_manager) << std::endl;
);
expr * e = m_rewrite_todo.back();