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fix #2422

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-07-24 09:47:25 -07:00
parent 1a70fce92e
commit 019d78e219
1 changed files with 13 additions and 13 deletions
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26
src/smt/theory_seq.cpp
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@ -4998,10 +4998,7 @@ this translates to:
0 <= i <= |s| -> len(x) = i
0 <= i <= |s| & 0 <= l <= |s| - i -> |e| = l
0 <= i <= |s| & |s| < l + i -> |e| = |s| - i
i >= |s| => |e| = 0
i < 0 => |e| = 0
l <= 0 => |e| = 0
|e| = 0 => i < 0 | l <= 0 | i >= |s|
|e| = 0 <=> i < 0 | |s| <= i | l <= 0 | |s| <= 0
It follows that:
|e| = min(l, |s| - i) for 0 <= i < |s| and 0 < |l|
@ -5040,21 +5037,24 @@ void theory_seq::add_extract_axiom(expr* e) {
expr_ref zero(m_autil.mk_int(0), m);
literal i_ge_0 = mk_simplified_literal(m_autil.mk_ge(i, zero));
literal ls_le_i = mk_simplified_literal(m_autil.mk_le(mk_sub(i, ls), zero));
literal i_le_ls = mk_simplified_literal(m_autil.mk_le(mk_sub(i, ls), zero));
literal ls_le_i = mk_simplified_literal(m_autil.mk_le(mk_sub(ls, i), zero));
literal li_ge_ls = mk_simplified_literal(m_autil.mk_ge(ls_minus_i_l, zero));
literal l_ge_zero = mk_simplified_literal(m_autil.mk_ge(l, zero));
literal l_ge_0 = mk_simplified_literal(m_autil.mk_ge(l, zero));
literal l_le_0 = mk_simplified_literal(m_autil.mk_le(l, zero));
literal ls_le_0 = mk_simplified_literal(m_autil.mk_le(ls, zero));
literal le_is_0 = mk_eq(le, zero, false);
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, ~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_0, ~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_0, mk_eq(le, zero, false));
add_axiom(i_ge_0, le_is_0);
add_axiom(ls_le_i, le_is_0);
add_axiom(~ls_le_i, le_is_0);
add_axiom(~ls_le_0, le_is_0);
add_axiom(~le_is_0, ~i_ge_0, ~ls_le_i, ls_le_0);
add_axiom(~l_le_0, le_is_0);
add_axiom(~le_is_0, ~i_ge_0, ls_le_i, ls_le_0, l_le_0);
}
void theory_seq::add_tail_axiom(expr* e, expr* s) {