bv_refinementt::approximationt &
bv_refinementt::add_approximation(
const exprt &expr, bvt &bv)
{
approximations.push_back(approximationt(approximations.size()));
approximationt &a=approximations.back(); // stable!
unsigned width=boolbv_width(expr.type());
assert(width!=0);
a.expr=expr;
a.result_bv=prop.new_variables(width);
a.no_operands=expr.operands().size();
set_frozen(a.result_bv);
if(a.no_operands==1)
{
a.op0_bv=convert_bv(expr.op0());
set_frozen(a.op0_bv);
}
else if(a.no_operands==2)
{
a.op0_bv=convert_bv(expr.op0());
a.op1_bv=convert_bv(expr.op1());
set_frozen(a.op0_bv);
set_frozen(a.op1_bv);
}
else if(a.no_operands==3)
{
a.op0_bv=convert_bv(expr.op0());
a.op1_bv=convert_bv(expr.op1());
a.op2_bv=convert_bv(expr.op2());
set_frozen(a.op0_bv);
set_frozen(a.op1_bv);
set_frozen(a.op2_bv);
}
else
assert(false);
bv=a.result_bv;
initialize(a);
return a;
}
void prop_convt::set_frozen(const bvt &bv)
{
for(unsigned i=0; i<bv.size(); i++)
if(!bv[i].is_constant())
set_frozen(bv[i]);
}
