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fix #7389

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2024-09-22 02:41:11 +03:00
parent 0c48a50d59
commit d66609ea14
1 changed files with 25 additions and 0 deletions
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25
src/ast/rewriter/bv_rewriter.cpp
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@ -618,6 +618,31 @@ br_status bv_rewriter::mk_leq_core(bool is_signed, expr * a, expr * b, expr_ref
return BR_REWRITE3;
}
// #x000f <=_u a <=> not (a <=_u #x000f) or a = #x000f
i = bv_sz;
first_non_zero = UINT_MAX;
while (i > 0) {
--i;
if (!is_zero_bit(a, i)) {
first_non_zero = i;
break;
}
}
if (first_non_zero == UINT_MAX) {
// all bits are zero
result = m.mk_eq(b, mk_zero(bv_sz));
return BR_REWRITE1;
}
else if (first_non_zero < bv_sz - 1 && m_le2extract) {
result = m.mk_and(m.mk_eq(m_mk_extract(bv_sz - 1, first_non_zero + 1, b), mk_zero(bv_sz - first_non_zero - 1)),
m_util.mk_ule(m_mk_extract(first_non_zero, 0, b), m_mk_extract(first_non_zero, 0, a)));
result = m.mk_or(m.mk_not(result), m.mk_eq(a, b));
return BR_REWRITE_FULL;
}
}
#endif