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fix #4021

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-04-19 12:18:18 -07:00
parent 79b776fee5
commit 339a2568b2
2 changed files with 40 additions and 29 deletions
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67
src/smt/seq_axioms.cpp
View file

@ -52,8 +52,6 @@ expr_ref seq_axioms::mk_len(expr* s) {
return result;
}
literal seq_axioms::mk_literal(expr* _e) {
expr_ref e(_e, m);
if (a.is_arith_expr(e)) {
@ -86,10 +84,8 @@ this translates to:
It follows that:
|e| = min(l, |s| - i) for 0 <= i < |s| and 0 < |l|
*/
void seq_axioms::add_extract_axiom(expr* e) {
TRACE("seq", tout << mk_pp(e, m) << "\n";);
expr* s = nullptr, *i = nullptr, *l = nullptr;
@ -718,44 +714,59 @@ void seq_axioms::add_le_axiom(expr* n) {
add_axiom(~lt, le);
}
/**
Unit is injective:
u = inv-unit(unit(u))
*/
void seq_axioms::add_unit_axiom(expr* n) {
expr* u = nullptr;
VERIFY(seq.str.is_unit(n, u));
add_axiom(mk_eq(u, m_sk.mk_unit_inv(n)));
}
/**
suffix(s, t) => s = seq.suffix_inv(s, t) + t
~suffix(s, t) => len(s) > len(t) or s = y(s, t) + unit(c(s, t)) + x(s, t)
~suffix(s, t) => len(s) > len(t) or t = z(s, t) + unit(d(s, t)) + x(s, t)
~suffix(s, t) => len(s) > len(t) or c(s,t) != d(s,t)
*/
void seq_axioms::add_suffix_axiom(expr* e) {
expr* e1 = nullptr, *e2 = nullptr;
VERIFY(seq.str.is_suffix(e, e1, e2));
expr* s = nullptr, *t = nullptr;
VERIFY(seq.str.is_suffix(e, s, t));
literal lit = mk_literal(e);
literal e1_gt_e2 = mk_ge(mk_sub(mk_len(e1), mk_len(e2)), 1);
literal s_gt_t = mk_ge(mk_sub(mk_len(s), mk_len(t)), 1);
sort* char_sort = nullptr;
VERIFY(seq.is_seq(m.get_sort(e1), char_sort));
expr_ref x = m_sk.mk(symbol("seq.suffix.x"), e1, e2);
expr_ref y = m_sk.mk(symbol("seq.suffix.y"), e1, e2);
expr_ref z = m_sk.mk(symbol("seq.suffix.z"), e1, e2);
expr_ref c = m_sk.mk(symbol("seq.suffix.c"), e1, e2, nullptr, nullptr, char_sort);
expr_ref d = m_sk.mk(symbol("seq.suffix.d"), e1, e2, nullptr, nullptr, char_sort);
add_axiom(lit, e1_gt_e2, mk_seq_eq(e1, mk_concat(y, seq.str.mk_unit(c), x)));
add_axiom(lit, e1_gt_e2, mk_seq_eq(e2, mk_concat(z, seq.str.mk_unit(d), x)));
add_axiom(lit, e1_gt_e2, ~mk_eq(c, d));
VERIFY(seq.is_seq(m.get_sort(s), char_sort));
expr_ref x = m_sk.mk("seq.suffix.x", s, t);
expr_ref y = m_sk.mk("seq.suffix.y", s, t);
expr_ref z = m_sk.mk("seq.suffix.z", s, t);
expr_ref c = m_sk.mk("seq.suffix.c", s, t, char_sort);
expr_ref d = m_sk.mk("seq.suffix.d", s, t, char_sort);
add_axiom(lit, s_gt_t, mk_seq_eq(s, mk_concat(y, seq.str.mk_unit(c), x)));
add_axiom(lit, s_gt_t, mk_seq_eq(t, mk_concat(z, seq.str.mk_unit(d), x)));
add_axiom(lit, s_gt_t, ~mk_eq(c, d));
}
void seq_axioms::add_prefix_axiom(expr* e) {
expr* e1 = nullptr, *e2 = nullptr;
VERIFY(seq.str.is_prefix(e, e1, e2));
expr* s = nullptr, *t = nullptr;
VERIFY(seq.str.is_prefix(e, s, t));
literal lit = mk_literal(e);
literal e1_gt_e2 = mk_ge(mk_sub(mk_len(e1), mk_len(e2)), 1);
literal s_gt_t = mk_ge(mk_sub(mk_len(s), mk_len(t)), 1);
sort* char_sort = nullptr;
VERIFY(seq.is_seq(m.get_sort(e1), char_sort));
expr_ref x = m_sk.mk(symbol("seq.prefix.x"), e1, e2);
expr_ref y = m_sk.mk(symbol("seq.prefix.y"), e1, e2);
expr_ref z = m_sk.mk(symbol("seq.prefix.z"), e1, e2);
expr_ref c = m_sk.mk(symbol("seq.prefix.c"), e1, e2, nullptr, nullptr, char_sort);
expr_ref d = m_sk.mk(symbol("seq.prefix.d"), e1, e2, nullptr, nullptr, char_sort);
add_axiom(lit, e1_gt_e2, mk_seq_eq(e1, mk_concat(x, seq.str.mk_unit(c), y)));
add_axiom(lit, e1_gt_e2, mk_seq_eq(e2, mk_concat(x, seq.str.mk_unit(d), z)), mk_seq_eq(e2, x));
add_axiom(lit, e1_gt_e2, ~mk_eq(c, d));
VERIFY(seq.is_seq(m.get_sort(s), char_sort));
expr_ref x = m_sk.mk("seq.prefix.x", s, t);
expr_ref y = m_sk.mk("seq.prefix.y", s, t);
expr_ref z = m_sk.mk("seq.prefix.z", s, t);
expr_ref c = m_sk.mk("seq.prefix.c", s, t, char_sort);
expr_ref d = m_sk.mk("seq.prefix.d", s, t, char_sort);
add_axiom(lit, s_gt_t, mk_seq_eq(s, mk_concat(x, seq.str.mk_unit(c), y)));
add_axiom(lit, s_gt_t, mk_seq_eq(t, mk_concat(x, seq.str.mk_unit(d), z)), mk_seq_eq(t, x));
add_axiom(lit, s_gt_t, ~mk_eq(c, d));
}
/***

2
src/tactic/core/nnf_tactic.cpp
View file

@ -70,7 +70,7 @@ public:
proof_ref new_pr(m);
unsigned sz = g->size();
for (unsigned i = 0; i < sz; i++) {
for (unsigned i = 0; !g->inconsistent() && i < sz; i++) {
expr * curr = g->form(i);
local_nnf(curr, defs, def_prs, new_curr, new_pr);
if (produce_proofs) {