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reducing dependencies on simplifier

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-08-22 15:09:34 -07:00
parent a206362cef
commit e2b46257d6
18 changed files with 289 additions and 215 deletions
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60
src/ast/rewriter/poly_rewriter_def.h
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@ -931,3 +931,63 @@ expr* poly_rewriter<Config>::merge_muls(expr* x, expr* y) {
m1[k] = mk_add_app(2, args);
return mk_mul_app(k+1, m1.c_ptr());
}
template<typename Config>
bool poly_rewriter<Config>::is_times_minus_one(expr * n, expr* & r) const {
if (is_mul(n) && to_app(n)->get_num_args() == 2 && is_minus_one(to_app(n)->get_arg(0))) {
r = to_app(n)->get_arg(1);
return true;
}
return false;
}
/**
\brief Return true if n is can be put into the form (+ v t) or (+ (- v) t)
\c inv = true will contain true if (- v) is found, and false otherwise.
*/
template<typename Config>
bool poly_rewriter<Config>::is_var_plus_ground(expr * n, bool & inv, var * & v, expr_ref & t) {
if (!is_add(n) || is_ground(n))
return false;
ptr_buffer<expr> args;
v = 0;
expr * curr = to_app(n);
bool stop = false;
inv = false;
while (!stop) {
expr * arg;
expr * neg_arg;
if (is_add(curr)) {
arg = to_app(curr)->get_arg(0);
curr = to_app(curr)->get_arg(1);
}
else {
arg = curr;
stop = true;
}
if (is_ground(arg)) {
TRACE("model_checker_bug", tout << "pushing:\n" << mk_pp(arg, m()) << "\n";);
args.push_back(arg);
}
else if (is_var(arg)) {
if (v != 0)
return false; // already found variable
v = to_var(arg);
}
else if (is_times_minus_one(arg, neg_arg) && is_var(neg_arg)) {
if (v != 0)
return false; // already found variable
v = to_var(neg_arg);
inv = true;
}
else {
return false; // non ground term.
}
}
if (v == 0)
return false; // did not find variable
SASSERT(!args.empty());
mk_add(args.size(), args.c_ptr(), t);
return true;
}