mirror of
https://github.com/Z3Prover/z3
synced 2025-04-10 03:07:07 +00:00
make semantics of extract/substr deterministic. Issue #781
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
parent
fa8427258a
commit
e65d80dedd
|
@ -3259,15 +3259,18 @@ bool theory_seq::get_length(expr* e, rational& val) const {
|
|||
|
||||
let e = extract(s, i, l)
|
||||
|
||||
0 <= i <= len(s) -> prefix(xe,s)
|
||||
0 <= i <= len(s) -> len(x) = i
|
||||
0 <= i <= len(s) & 0 <= l <= len(s) - i -> len(e) = l
|
||||
0 <= i <= len(s) & len(s) < l + i -> len(e) = len(s) - i
|
||||
0 <= i <= len(s) & l < 0 -> len(e) = 0
|
||||
* i < 0 -> e = empty
|
||||
* i > len(s) -> e = empty
|
||||
0 <= i <= |s| -> prefix(xe,s)
|
||||
0 <= i <= |s| -> len(x) = i
|
||||
0 <= i <= |s| & 0 <= l <= |s| - i -> |e| = l
|
||||
0 <= i <= |s| & |s| < l + i -> |e| = |s| - i
|
||||
0 <= i <= |s| & l < 0 -> |e| = 0
|
||||
i >= |s| => |e| = 0
|
||||
i < 0 => |e| = 0
|
||||
l <= 0 => |e| = 0
|
||||
|
||||
It follows that:
|
||||
|e| = min(l, |s| - i) for 0 <= i < |s| and 0 < |l|
|
||||
|
||||
|
||||
|
||||
*/
|
||||
|
||||
|
@ -3301,16 +3304,20 @@ void theory_seq::add_extract_axiom(expr* e) {
|
|||
expr_ref zero(m_autil.mk_int(0), m);
|
||||
|
||||
literal i_ge_0 = mk_literal(m_autil.mk_ge(i, zero));
|
||||
literal i_le_ls = mk_literal(m_autil.mk_le(mk_sub(i, ls), zero));
|
||||
literal ls_le_i = mk_literal(m_autil.mk_le(mk_sub(i, ls), zero));
|
||||
literal li_ge_ls = mk_literal(m_autil.mk_ge(ls_minus_i_l, zero));
|
||||
literal l_ge_zero = mk_literal(m_autil.mk_ge(l, zero));
|
||||
literal ls_le_0 = mk_literal(m_autil.mk_le(ls, zero));
|
||||
|
||||
// add_axiom(~i_ge_0, ~i_le_ls, mk_literal(m_util.str.mk_prefix(xe, s)));
|
||||
add_axiom(~i_ge_0, ~i_le_ls, mk_seq_eq(xey, s));
|
||||
add_axiom(~i_ge_0, ~i_le_ls, mk_eq(lx, i, false));
|
||||
add_axiom(~i_ge_0, ~i_le_ls, ~l_ge_zero, ~li_ge_ls, mk_eq(le, l, false));
|
||||
add_axiom(~i_ge_0, ~i_le_ls, li_ge_ls, mk_eq(le, mk_sub(ls, i), false));
|
||||
add_axiom(~i_ge_0, ~i_le_ls, l_ge_zero, mk_eq(le, zero, false));
|
||||
// add_axiom(~i_ge_0, ~ls_le_i, mk_literal(m_util.str.mk_prefix(xe, s)));
|
||||
add_axiom(~i_ge_0, ~ls_le_i, mk_seq_eq(xey, s));
|
||||
add_axiom(~i_ge_0, ~ls_le_i, mk_eq(lx, i, false));
|
||||
add_axiom(~i_ge_0, ~ls_le_i, ~l_ge_zero, ~li_ge_ls, mk_eq(le, l, false));
|
||||
add_axiom(~i_ge_0, ~ls_le_i, li_ge_ls, mk_eq(le, mk_sub(ls, i), false));
|
||||
add_axiom(~i_ge_0, ~ls_le_i, l_ge_zero, mk_eq(le, zero, false));
|
||||
add_axiom(i_ge_0, mk_eq(le, zero, false));
|
||||
add_axiom(ls_le_i, mk_eq(le, zero, false));
|
||||
add_axiom(~ls_le_0, mk_eq(le, zero, false));
|
||||
}
|
||||
|
||||
void theory_seq::add_tail_axiom(expr* e, expr* s) {
|
||||
|
|
Loading…
Reference in a new issue