/* Check if the constraints in "set" imply any stride on set dimension "pos" and
* store the results in data->stride and data->offset.
*
* In particular, compute the affine hull and then check if
* any of the constraints in the hull impose any stride on the dimension.
* If no such constraint can be found, then the offset is taken
* to be the zero expression and the stride is taken to be one.
*/
static void set_detect_stride(__isl_keep isl_set *set, int pos,
struct isl_detect_stride_data *data)
{
isl_basic_set *hull;
hull = isl_set_affine_hull(isl_set_copy(set));
data->pos = pos;
data->found = 0;
data->stride = NULL;
data->offset = NULL;
if (isl_basic_set_foreach_constraint(hull, &detect_stride, data) < 0)
goto error;
if (!data->found) {
data->stride = isl_val_one(isl_set_get_ctx(set));
if (data->want_offset) {
isl_space *space;
isl_local_space *ls;
space = isl_set_get_space(set);
ls = isl_local_space_from_space(space);
data->offset = isl_aff_zero_on_domain(ls);
}
}
isl_basic_set_free(hull);
return;
error:
isl_basic_set_free(hull);
data->stride = isl_val_free(data->stride);
data->offset = isl_aff_free(data->offset);
}
/* Check if dimension "dim" belongs to a residue class
* i_dim \equiv r mod m
* with m != 1 and if so return m in *modulo and r in *residue.
* As a special case, when i_dim has a fixed value v, then
* *modulo is set to 0 and *residue to v.
*
* If i_dim does not belong to such a residue class, then *modulo
* is set to 1 and *residue is set to 0.
*/
isl_stat isl_set_dim_residue_class_val(__isl_keep isl_set *set,
int pos, __isl_give isl_val **modulo, __isl_give isl_val **residue)
{
*modulo = NULL;
*residue = NULL;
if (!set)
return isl_stat_error;
*modulo = isl_val_alloc(isl_set_get_ctx(set));
*residue = isl_val_alloc(isl_set_get_ctx(set));
if (!*modulo || !*residue)
goto error;
if (isl_set_dim_residue_class(set, pos,
&(*modulo)->n, &(*residue)->n) < 0)
goto error;
isl_int_set_si((*modulo)->d, 1);
isl_int_set_si((*residue)->d, 1);
return isl_stat_ok;
error:
isl_val_free(*modulo);
isl_val_free(*residue);
return isl_stat_error;
}
