+void be_peephole_new_node(ir_node * nw)
+{
+ be_liveness_introduce(lv, nw);
+}
+
+/**
+ * must be called from peephole optimisations before a node will be killed
+ * and its users will be redirected to new_node.
+ * so bepeephole can update it's internal state.
+ *
+ * Note: killing a node and rewiring os only allowed if new_node produces
+ * the same registers as old_node.
+ */
+void be_peephole_before_exchange(const ir_node *old_node, ir_node *new_node)
+{
+ const arch_register_t *reg;
+ const arch_register_class_t *cls;
+ unsigned reg_idx;
+ unsigned cls_idx;
+
+ DBG((dbg, LEVEL_1, "About to exchange and kill %+F with %+F\n", old_node, new_node));
+
+ if (current_node == old_node) {
+ /* next node to be processed will be killed. Its scheduling predecessor
+ * must be processed next. */
+ current_node = sched_next(current_node);
+ assert (!is_Bad(current_node));
+ }
+
+ if (!mode_is_data(get_irn_mode(old_node)))
+ return;
+
+ reg = arch_get_irn_register(arch_env, old_node);
+ if (reg == NULL) {
+ panic("No register assigned at %+F", old_node);
+ }
+ assert(reg == arch_get_irn_register(arch_env, new_node) &&
+ "KILLING a node and replacing by different register is not allowed");
+
+ cls = arch_register_get_class(reg);
+ reg_idx = arch_register_get_index(reg);
+ cls_idx = arch_register_class_index(cls);
+
+ if (register_values[cls_idx][reg_idx] == old_node) {
+ register_values[cls_idx][reg_idx] = new_node;
+ }
+
+ be_liveness_remove(lv, old_node);
+}
+
+void be_peephole_exchange(ir_node *old, ir_node *nw)
+{
+ be_peephole_before_exchange(old, nw);
+ sched_remove(old);
+ exchange(old, nw);
+ be_peephole_new_node(nw);
+}
+
+/**
+ * block-walker: run peephole optimization on the given block.
+ */