+/** 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_irn_get_flags(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, 0, 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;
+}