+static void belady(ir_node *blk, void *env);
+
+/*
+ * Computes set of live-ins for each block with multiple predecessors
+ * and notifies spill algorithm which phis need to be spilled
+ */
+static void spill_phi_walker(ir_node *block, void *data) {
+ belady_env_t *env = data;
+ block_info_t *block_info;
+ ir_node *first, *irn;
+ loc_t loc, *starters;
+ int i, len, ws_count;
+
+ if(get_Block_n_cfgpreds(block) == 1 && get_irg_start_block(get_irn_irg(block)) != block)
+ return;
+
+ block_info = new_block_info(&env->ob);
+ set_block_info(block, block_info);
+
+ /* Collect all values living at start of block */
+ starters = NEW_ARR_F(loc_t, 0);
+
+ /* rebuild schedule time information, because it seems to be broken */
+ sched_renumber(block);
+
+ DBG((dbg, DBG_START, "Living at start of %+F:\n", block));
+ first = sched_first(block);
+ sched_foreach(block, irn) {
+ if(!is_Phi(irn))
+ break;
+ if(!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irn))
+ continue;
+
+ loc.irn = irn;
+ loc.time = get_distance(env, first, 0, irn, 0);
+ ARR_APP1(loc_t, starters, loc);
+ DBG((dbg, DBG_START, " %+F:\n", irn));
+ }
+
+ be_lv_foreach(env->cenv->lv, block, be_lv_state_in, i) {
+ ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
+ if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irn))
+ continue;
+
+ loc.irn = irn;
+ loc.time = get_distance(env, first, 0, irn, 0);
+ ARR_APP1(loc_t, starters, loc);
+ DBG((dbg, DBG_START, " %+F:\n", irn));
+ }
+
+ // Sort start values by first use
+ qsort(starters, ARR_LEN(starters), sizeof(starters[0]), loc_compare);
+
+ /* Copy the best ones from starters to start workset */
+ ws_count = MIN(ARR_LEN(starters), env->n_regs);
+ block_info->ws_start = new_workset(env, &env->ob);
+ workset_bulk_fill(block_info->ws_start, ws_count, starters);
+
+ /* The phis of this block which are not in the start set have to be spilled later. */
+ for (i = ws_count, len = ARR_LEN(starters); i < len; ++i) {
+ irn = starters[i].irn;
+ if (!is_Phi(irn) || get_nodes_block(irn) != block)
+ continue;
+
+ be_spill_phi(env->senv, irn);
+ }
+
+ DEL_ARR_F(starters);
+}
+
+/**
+ * Collects all values live-in at block @p blk and all phi results in this block.
+ * Then it adds the best values (at most n_regs) to the blocks start_workset.
+ * The phis among the remaining values get spilled: Introduce psudo-copies of
+ * their args to break interference and make it possible to spill them to the
+ * same spill slot.
+ */
+static block_info_t *compute_block_start_info(belady_env_t *env, ir_node *block) {
+ ir_node *pred_block;
+ block_info_t *res, *pred_info;
+
+ /* Have we seen this block before? */
+ res = get_block_info(block);
+ if (res)
+ return res;
+
+ /* Create the block info for this block. */
+ res = new_block_info(&env->ob);
+ set_block_info(block, res);
+
+ /* Use endset of predecessor block as startset */
+ assert(get_Block_n_cfgpreds(block) == 1 && block != get_irg_start_block(get_irn_irg(block)));
+ pred_block = get_Block_cfgpred_block(block, 0);
+ pred_info = get_block_info(pred_block);
+
+ /* if pred block has not been processed yet, do it now */
+ if (pred_info == NULL || pred_info->processed == 0) {
+ belady(pred_block, env);
+ pred_info = get_block_info(pred_block);
+ }
+
+ /* now we have an end_set of pred */
+ assert(pred_info->ws_end && "The recursive call (above) is supposed to compute an end_set");
+ res->ws_start = workset_clone(env, &env->ob, pred_info->ws_end);
+
+ return res;
+}
+
+