+enum {
+ AVAILABLE_EVERYWHERE,
+ AVAILABLE_NOWHERE,
+ AVAILABLE_PARTLY,
+ AVAILABLE_UNKNOWN
+};
+
+static unsigned available_in_all_preds(workset_t* const* pred_worksets,
+ size_t n_pred_worksets,
+ const ir_node *value, bool is_local_phi)
+{
+ size_t i;
+ bool avail_everywhere = true;
+ bool avail_nowhere = true;
+
+ assert(n_pred_worksets > 0);
+
+ /* value available in all preds? */
+ for (i = 0; i < n_pred_worksets; ++i) {
+ bool found = false;
+ const workset_t *p_workset = pred_worksets[i];
+ int p_len = workset_get_length(p_workset);
+ int p_i;
+ const ir_node *l_value;
+
+ if (is_local_phi) {
+ assert(is_Phi(value));
+ l_value = get_irn_n(value, i);
+ } else {
+ l_value = value;
+ }
+
+ for (p_i = 0; p_i < p_len; ++p_i) {
+ const loc_t *p_l = &p_workset->vals[p_i];
+ if (p_l->node != l_value)
+ continue;
+
+ found = true;
+ break;
+ }
+
+ if (found) {
+ avail_nowhere = false;
+ } else {
+ avail_everywhere = false;
+ }
+ }
+
+ if (avail_everywhere) {
+ assert(!avail_nowhere);
+ return AVAILABLE_EVERYWHERE;
+ } else if (avail_nowhere) {
+ return AVAILABLE_NOWHERE;
+ } else {
+ return AVAILABLE_PARTLY;
+ }
+}
+
+/** Decides whether a specific node should be in the start workset or not
+ *
+ * @param env belady environment
+ * @param first
+ * @param node the node to test
+ * @param loop the loop of the node
+ */
+static loc_t to_take_or_not_to_take(ir_node* first, ir_node *node,
+ ir_loop *loop, unsigned available)
+{
+ be_next_use_t next_use;
+ loc_t loc;
+
+ loc.time = USES_INFINITY;
+ loc.node = node;
+ loc.spilled = false;
+
+ if (!arch_irn_consider_in_reg_alloc(cls, node)) {
+ loc.time = USES_INFINITY;
+ return loc;
+ }
+
+ /* We have to keep nonspillable nodes in the workingset */
+ if (arch_get_irn_flags(skip_Proj_const(node)) & arch_irn_flags_dont_spill) {
+ loc.time = 0;
+ DB((dbg, DBG_START, " %+F taken (dontspill node)\n", node, loc.time));
+ return loc;
+ }
+
+ next_use = be_get_next_use(uses, first, node, 0);
+ if (USES_IS_INFINITE(next_use.time)) {
+ /* the nodes marked as live in shouldn't be dead, so it must be a phi */
+ assert(is_Phi(node));
+ loc.time = USES_INFINITY;
+ DB((dbg, DBG_START, " %+F not taken (dead)\n", node));
+ return loc;
+ }
+
+ loc.time = next_use.time;
+
+ if (improve_known_preds) {
+ if (available == AVAILABLE_EVERYWHERE) {
+ DB((dbg, DBG_START, " %+F taken (%u, live in all preds)\n",
+ node, loc.time));
+ return loc;
+ } else if (available == AVAILABLE_NOWHERE) {
+ DB((dbg, DBG_START, " %+F not taken (%u, live in no pred)\n",
+ node, loc.time));
+ loc.time = USES_INFINITY;
+ return loc;
+ }
+ }
+
+ if (!respectloopdepth || next_use.outermost_loop >= get_loop_depth(loop)) {
+ DB((dbg, DBG_START, " %+F taken (%u, loop %d)\n", node, loc.time,
+ next_use.outermost_loop));
+ } else {
+ loc.time = USES_PENDING;
+ DB((dbg, DBG_START, " %+F delayed (outerdepth %d < loopdepth %d)\n",
+ node, next_use.outermost_loop, get_loop_depth(loop)));
+ }
+
+ return loc;
+}