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Derive with ranges (#9963)

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Margus Veanes <margus@microsoft.com>
Co-authored-by: Margus Veanes <veanes@users.noreply.github.com>
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Nikolaj Bjorner 2026-06-25 18:47:25 -07:00 • committed by GitHub
parent 0596c7c634
commit 22c2635786
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GPG key ID: B5690EEEBB952194
24 changed files with 3462 additions and 1000 deletions
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45
src/ast/rewriter/seq_subset.cpp
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@ -19,7 +19,7 @@ Author:
bool seq_subset::is_subset_rec(expr* a, expr* b, unsigned depth) const {
while (true) {
if (a == b)
return true;
if (m_re.is_empty(a))
@ -30,7 +30,7 @@ bool seq_subset::is_subset_rec(expr* a, expr* b, unsigned depth) const {
return true;
if (depth >= m_max_depth)
return false;
return false;
expr* a1 = nullptr, * a2 = nullptr, * b1 = nullptr, * b2 = nullptr;
unsigned la, ua, lb, ub;
@ -39,16 +39,12 @@ bool seq_subset::is_subset_rec(expr* a, expr* b, unsigned depth) const {
if (m_re.is_dot_plus(b) && m_re.get_info(a).nullable == l_false)
return true;
// a ⊆ a*
if (m_re.is_star(b, b1) && is_subset_rec(a, b1, depth))
return true;
// e ⊆ a*
if (m_re.is_epsilon(a) && m_re.is_star(b, b1))
return true;
// R ⊆ R*
if (m_re.is_star(b, b1) && is_subset_rec(a, b1, depth + 1))
// a ⊆ a*: if b = b1* and a ⊆ b1, then a ⊆ b1*
if (m_re.is_star(b, b1) && is_subset_rec(a, b1, depth))
return true;
// R1* ⊆ R2* if R1 ⊆ R2
@ -112,6 +108,12 @@ bool seq_subset::is_subset_rec(expr* a, expr* b, unsigned depth) const {
if (m_re.is_concat(b, b1, b2) && m_re.is_full_seq(b1) && is_subset_rec(a, b2, depth))
return true;
// prefix absorption: P·R' ⊆ Σ*·R' for any prefix P (since P ⊆ Σ*).
// Detect that a has R' (= b2) as a concatenation suffix, where b = Σ*·R'.
// Covers contains-patterns, e.g. Σ*·a·Σ*·b·Σ* ⊆ Σ*·b·Σ*.
if (m_re.is_concat(b, b1, b2) && m_re.is_full_seq(b1) && ends_with(a, b2))
return true;
// R ⊆ R'·Σ* if R ⊆ R'
if (m_re.is_concat(b, b1, b2) && m_re.is_full_seq(b2) && is_subset_rec(a, b1, depth))
return true;
@ -144,3 +146,30 @@ bool seq_subset::is_subset_rec(expr* a, expr* b, unsigned depth) const {
bool seq_subset::is_subset(expr* a, expr* b) const {
return is_subset_rec(a, b, 0);
}
bool seq_subset::ends_with(expr* a, expr* suf) const {
if (a == suf)
return true;
// Flatten both regexes into their sequence of concatenation factors
// (independent of left/right associativity) and test list-suffix equality.
ptr_vector<expr> af, sf;
flatten_concat(a, af);
flatten_concat(suf, sf);
if (sf.size() > af.size())
return false;
unsigned off = af.size() - sf.size();
for (unsigned i = 0; i < sf.size(); ++i)
if (af[off + i] != sf[i])
return false;
return true;
}
void seq_subset::flatten_concat(expr* a, ptr_vector<expr>& out) const {
expr* a1 = nullptr, * a2 = nullptr;
if (m_re.is_concat(a, a1, a2)) {
flatten_concat(a1, out);
flatten_concat(a2, out);
}
else
out.push_back(a);
}