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fix #2019 - insufficient axioms for special cases

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2018-12-08 13:57:35 +01:00
parent a20e68facc
commit 38b5e6de56
3 changed files with 17 additions and 14 deletions
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2
src/ast/ast_smt2_pp.cpp
View file

@ -238,7 +238,7 @@ format * smt2_pp_environment::pp_float_literal(app * t, bool use_bv_lits, bool u
string_buffer<> buf;
VERIFY(get_futil().is_numeral(t, v));
if (fm.is_nan(v)) {
buf << "(_ NaN " << v.get().get_ebits() << " " << v.get().get_sbits() << ")";
buf << "(_ NaN " << v.get().get_ebits() << " " << v.get().get_sbits() << ")";
return mk_string(m, buf.c_str());
}
else if (fm.is_pinf(v)) {

12
src/ast/rewriter/bv_rewriter.cpp
View file

@ -780,13 +780,11 @@ br_status bv_rewriter::mk_extract(unsigned high, unsigned low, expr * arg, expr_
}
expr* c = nullptr, *t = nullptr, *e = nullptr;
if (m().is_ite(arg, c, t, e)) {
if ((t->get_ref_count() == 1 && e->get_ref_count() == 1) ||
(!m().is_ite(t) && !m().is_ite(e))) {
//std::cout << "n-ite\n";
result = m().mk_ite(c, m_mk_extract(high, low, t), m_mk_extract(high, low, e));
return BR_REWRITE2;
}
if (m().is_ite(arg, c, t, e) &&
(t->get_ref_count() == 1 || !m().is_ite(t)) &&
(e->get_ref_count() == 1 || !m().is_ite(e))) {
result = m().mk_ite(c, m_mk_extract(high, low, t), m_mk_extract(high, low, e));
return BR_REWRITE2;
}
return BR_FAILED;

17
src/smt/theory_seq.cpp
View file

@ -2396,7 +2396,6 @@ bool theory_seq::is_var(expr* a) const {
!m_util.str.is_string(a) &&
!m_util.str.is_unit(a) &&
!m_util.str.is_itos(a) &&
!m_util.str.is_extract(a) &&
!m.is_ite(a);
}
@ -4812,11 +4811,15 @@ void theory_seq::add_extract_axiom(expr* e) {
void theory_seq::add_tail_axiom(expr* e, expr* s) {
expr_ref head(m), tail(m);
mk_decompose(s, head, tail);
add_axiom(mk_eq_empty(s), mk_seq_eq(s, mk_concat(head, e)));
literal emp = mk_eq_empty(s);
add_axiom(emp, mk_seq_eq(s, mk_concat(head, e)));
add_axiom(~emp, mk_eq_empty(e));
}
void theory_seq::add_drop_last_axiom(expr* e, expr* s) {
add_axiom(mk_eq_empty(s), mk_seq_eq(s, mk_concat(e, m_util.str.mk_unit(mk_last(s)))));
literal emp = mk_eq_empty(s);
add_axiom(emp, mk_seq_eq(s, mk_concat(e, m_util.str.mk_unit(mk_last(s)))));
add_axiom(~emp, mk_eq_empty(e));
}
bool theory_seq::is_drop_last(expr* s, expr* i, expr* l) {
@ -4857,6 +4860,7 @@ bool theory_seq::is_extract_suffix(expr* s, expr* i, expr* l) {
/*
0 <= l <= len(s) => s = ey & l = len(e)
len(s) < l => s = e
l < 0 => e = empty
*/
void theory_seq::add_extract_prefix_axiom(expr* e, expr* s, expr* l) {
TRACE("seq", tout << mk_pp(e, m) << " " << mk_pp(s, m) << " " << mk_pp(l, m) << "\n";);
@ -4872,12 +4876,13 @@ void theory_seq::add_extract_prefix_axiom(expr* e, expr* s, expr* l) {
add_axiom(~l_ge_0, ~l_le_s, mk_eq(l, le, false));
add_axiom(~l_ge_0, ~l_le_s, mk_eq(ls_minus_l, mk_len(y), false));
add_axiom(l_le_s, mk_eq(e, s, false));
add_axiom(l_ge_0, mk_eq_empty(e));
}
/*
0 <= i <= len(s) => s = xe & i = len(x)
i < 0 => len(e) = 0
i > len(s) => len(e) = 0
i < 0 => e = empty
i > len(s) => e = empty
*/
void theory_seq::add_extract_suffix_axiom(expr* e, expr* s, expr* i) {
expr_ref x(mk_skolem(m_pre, s, i), m);
@ -4885,7 +4890,7 @@ void theory_seq::add_extract_suffix_axiom(expr* e, expr* s, expr* i) {
expr_ref ls = mk_len(s);
expr_ref zero(m_autil.mk_int(0), m);
expr_ref xe = mk_concat(x, e);
literal le_is_0 = mk_eq(zero, mk_len(e), false);
literal le_is_0 = mk_eq_empty(e);
literal i_ge_0 = mk_simplified_literal(m_autil.mk_ge(i, zero));
literal i_le_s = mk_simplified_literal(m_autil.mk_le(mk_sub(i, ls), zero));
add_axiom(~i_ge_0, ~i_le_s, mk_seq_eq(s, xe));