+static int get_n_out_edges(const ir_node *irn) {
+ const ir_edge_t *edge;
+ int cnt = 0;
+
+ foreach_out_edge(irn, edge) {
+ cnt++;
+ }
+
+ return cnt;
+}
+
+static ir_node *belower_skip_proj(ir_node *irn) {
+ while(is_Proj(irn))
+ irn = get_Proj_pred(irn);
+ return irn;
+}
+
+static void fix_in(ir_node *irn, ir_node *old, ir_node *nw) {
+ int i, n;
+
+ irn = belower_skip_proj(irn);
+ n = get_irn_arity(irn);
+
+ for (i = 0; i < n; i++) {
+ if (get_irn_n(irn, i) == old) {
+ set_irn_n(irn, i, nw);
+ break;
+ }
+ }
+}
+
+static void gen_assure_different_pattern(ir_node *irn, be_irg_t *birg, ir_node *other_different) {
+ const arch_env_t *arch_env = birg->main_env->arch_env;
+ ir_node *in[2], *keep, *cpy, *temp;
+ ir_node *block = get_nodes_block(irn);
+ firm_dbg_module_t *mod = firm_dbg_register("firm.be.lower");
+ const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, other_different, -1);
+
+ if (arch_irn_is_ignore(arch_env, other_different)) {
+ DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore\n", irn));
+ return;
+ }
+
+ /* Make a not spillable copy of the different node */
+ /* this is needed because the different irn could be */
+ /* in block far far away */
+ /* The copy is optimized later if not needed */
+
+ temp = new_rd_Unknown(birg->irg, get_irn_mode(other_different));
+ cpy = be_new_Copy(cls, birg->irg, block, temp);
+ be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);
+
+ in[0] = irn;
+ in[1] = cpy;
+
+ /* Let the irn use the copy instead of the old other_different */
+ fix_in(irn, other_different, cpy);
+
+ /* Add the Keep resp. CopyKeep and reroute the users */
+ /* of the other_different irn in case of CopyKeep. */
+ if (get_n_out_edges(other_different) == 0) {
+ keep = be_new_Keep(cls, birg->irg, block, 2, in);
+ }
+ else {
+ keep = be_new_CopyKeep_single(cls, birg->irg, block, cpy, irn, get_irn_mode(other_different));
+ edges_reroute(other_different, keep, birg->irg);
+ }
+
+ /* after rerouting: let the copy point to the other_different irn */
+ set_irn_n(cpy, 0, other_different);
+
+ DBG((mod, LEVEL_1, "created %+F for %+F to assure should_be_different\n", keep, irn));
+}
+
+/**
+ * Checks if node has a should_be_different constraint in output
+ * and adds a Keep then to assure the constraint.
+ */
+static void assure_different_constraints(ir_node *irn, be_irg_t *birg) {
+ const arch_env_t *arch_env = birg->main_env->arch_env;
+ const arch_register_req_t *req;
+ arch_register_req_t req_temp;
+ int i, n;
+
+ req = arch_get_register_req(arch_env, &req_temp, irn, -1);
+
+ if (req) {
+ if (arch_register_req_is(req, should_be_different)) {
+ gen_assure_different_pattern(irn, birg, req->other_different);
+ }
+ else if (arch_register_req_is(req, should_be_different_from_all)) {
+ n = get_irn_arity(belower_skip_proj(irn));
+ for (i = 0; i < n; i++) {
+ gen_assure_different_pattern(irn, birg, get_irn_n(belower_skip_proj(irn), i));
+ }
+ }
+ }
+}
+
+
+
+/**
+ * Calls the functions to assure register constraints.
+ *
+ * @param irn The node to be checked for lowering
+ * @param walk_env The walker environment
+ */
+static void assure_constraints_walker(ir_node *irn, void *walk_env) {
+ if (is_Block(irn))
+ return;
+
+ if (mode_is_datab(get_irn_mode(irn)))
+ assure_different_constraints(irn, walk_env);
+
+ return;
+}
+
+
+
+/**
+ * Walks over all nodes to assure register constraints.
+ *
+ * @param birg The birg structure containing the irg
+ */
+void assure_constraints(be_irg_t *birg) {
+ irg_walk_blkwise_graph(birg->irg, NULL, assure_constraints_walker, birg);
+}
+
+
+
/**
* Calls the corresponding lowering function for the node.
*
/**
* Walks over all blocks in an irg and performs lowering need to be
- * done after register allocation (e.g. perm and spill/reload lowering).
+ * done after register allocation (e.g. perm lowering).
*
* @param chord_env The chordal environment containing the irg
* @param do_copy 1 == resolve cycles with a free reg if available