static int apply_alternating_path(bipartite_t const *const gr,
int *const matching,
bitset_t *const matched_left,
bitset_t *const matched_right)
{
bool done_something = false;
bitset_t *const tmp = bitset_alloca(gr->n_right);
for (unsigned left = 0; left < gr->n_left; ++left) {
bitset_t *left_adj = gr->adj[left];
bitset_copy(tmp, left_adj);
if (matching[left] >= 0) {
int old_right = matching[left];
/* Check of all neighbors of the left node are already matched.
* We cannot improve this edge then. */
if (bitset_contains(left_adj, matched_right))
continue;
bitset_andnot(tmp, matched_right);
unsigned right = bitset_next_set(tmp, 0);
assert(right != ~0u);
/* We have to find another left node which has the old right one as
* a neighbor. This node must not be part of a matching */
unsigned i;
for (i = 0; i < gr->n_left; ++i)
if (i != left && bitset_is_set(gr->adj[i], old_right) && !bitset_is_set(matched_left, i))
break;
/* If no such node can be found, exit. */
if (i >= gr->n_left)
continue;
/* Else, we can improve this edge. */
matching[left] = right;
matching[i] = old_right;
bitset_set(matched_left, i);
bitset_set(matched_right, right);
done_something = true;
} else {
/* We have to create a new single edge */
assert(!bitset_is_set(matched_left, left));
bitset_andnot(tmp, matched_right);
if (bitset_is_empty(tmp))
continue;
unsigned right = bitset_next_set(tmp, 0);
assert(!bitset_is_set(matched_right, right));
matching[left] = right;
bitset_set(matched_left, left);
bitset_set(matched_right, right);
done_something = true;
}
}
return done_something;
}
int has_backedges(const ir_node *n)
{
bitset_t *ba = get_backarray(n);
if (ba != NULL) {
return !bitset_is_empty(ba);
}
return 0;
}
// returns true iff this labelset is empty
static SB_INLINE bool labelset_is_empty(LabelSet *ls) {
if (ls == 0) return true;
return bitset_is_empty(*(ls->set));
}