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fix #5687

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2021-12-01 10:08:29 -08:00
parent c6a5aa0cc4
commit 87aec8819f
1 changed files with 23 additions and 7 deletions
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30
src/ast/rewriter/bv_rewriter.cpp
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@ -1446,18 +1446,34 @@ br_status bv_rewriter::mk_bv2int(expr * arg, expr_ref & result) {
bool bv_rewriter::is_mul_no_overflow(expr* e) { bool bv_rewriter::is_mul_no_overflow(expr* e) {
if (!m_util.is_bv_mul(e)) return false; if (!m_util.is_bv_mul(e))
return false;
unsigned sz = get_bv_size(e); unsigned sz = get_bv_size(e);
unsigned sum = 0; unsigned sum = 0;
for (expr* x : *to_app(e)) sum += sz-num_leading_zero_bits(x); for (expr* x : *to_app(e))
return sum < sz; sum += sz - num_leading_zero_bits(x);
if (sum > sz + 1)
return false;
if (sum <= sz)
return true;
rational v;
unsigned shift;
for (expr* x : *to_app(e))
if (m_util.is_numeral(x, v) && v.is_power_of_two(shift))
return true;
return false;
} }
bool bv_rewriter::is_add_no_overflow(expr* e) { bool bv_rewriter::is_add_no_overflow(expr* e) {
if (!is_add(e)) return false; if (!is_add(e))
for (expr* x : *to_app(e)) { return false;
if (0 == num_leading_zero_bits(x)) return false; unsigned num_args = to_app(e)->get_num_args();
} if (num_args <= 1)
return true;
num_args -= 2;
for (expr* x : *to_app(e))
if (num_args >= num_leading_zero_bits(x))
return false;
return true; return true;
} }