+bool be_can_move_up(ir_heights_t *heights, const ir_node *node,
+ const ir_node *after)
+{
+ unsigned n_outs = arch_get_irn_n_outs(node);
+ const ir_node *node_block = get_nodes_block(node);
+ const ir_node *after_block = get_block_const(after);
+ const ir_node *schedpoint;
+ if (node_block != after_block) {
+ /* currently we can move up exactly 1 block */
+ assert(get_Block_cfgpred_block(node_block, 0) == after_block);
+ ir_node *first = sched_first(node_block);
+
+ /* do not move nodes changing memory */
+ if (is_memop(node)) {
+ ir_node *meminput = get_memop_mem(node);
+ if (!is_NoMem(meminput))
+ return false;
+ }
+
+ /* make sure we can move to the beginning of the succ block */
+ if (node != first && !be_can_move_up(heights, node, sched_prev(first)))
+ return false;
+
+ /* check if node overrides any of live-in values of other successors */
+ ir_graph *irg = get_irn_irg(node);
+ be_lv_t *lv = be_get_irg_liveness(irg);
+ foreach_block_succ(after_block, edge) {
+ ir_node *succ = get_edge_src_irn(edge);
+ if (succ == node_block)
+ continue;
+
+ be_lv_foreach(lv, succ, be_lv_state_in, live_node) {
+ const arch_register_t *reg = arch_get_irn_register(live_node);
+ const arch_register_req_t *req = arch_get_irn_register_req(live_node);
+ for (unsigned o = 0; o < n_outs; ++o) {
+ const arch_register_t *outreg
+ = arch_get_irn_register_out(node, o);
+ const arch_register_req_t *outreq
+ = arch_get_irn_register_req_out(node, o);
+ if (overlapping_regs(outreg, outreq, reg, req))
+ return false;
+ }
+ }
+ sched_foreach(succ, phi) {
+ if (!is_Phi(phi))
+ break;
+ const arch_register_t *reg = arch_get_irn_register(phi);
+ const arch_register_req_t *req = arch_get_irn_register_req(phi);
+ for (unsigned o = 0; o < n_outs; ++o) {
+ const arch_register_t *outreg
+ = arch_get_irn_register_out(node, o);
+ const arch_register_req_t *outreq
+ = arch_get_irn_register_req_out(node, o);
+ if (overlapping_regs(outreg, outreq, reg, req))
+ return false;
+ }
+ }
+ }
+ schedpoint = sched_last(after_block);
+ } else {
+ schedpoint = sched_prev(node);
+ }
+
+ /* move schedule upwards until we hit the "after" node */
+ while (schedpoint != after) {
+ /* TODO: the following heights query only works for nodes in the same
+ * block, otherwise we have to be conservative here */
+ if (get_nodes_block(node) != get_nodes_block(schedpoint))
+ return false;
+ /* node must not depend on schedpoint */
+ if (heights_reachable_in_block(heights, node, schedpoint))
+ return false;
+
+ /* node must not overwrite registers used by schedpoint */
+ int arity = get_irn_arity(schedpoint);
+ for (int i = 0; i < arity; ++i) {
+ const arch_register_t *reg
+ = arch_get_irn_register_in(schedpoint, i);
+ if (reg == NULL)
+ continue;
+ const arch_register_req_t *in_req
+ = arch_get_irn_register_req_in(schedpoint, i);
+ for (unsigned o = 0; o < n_outs; ++o) {
+ const arch_register_t *outreg
+ = arch_get_irn_register_out(node, o);
+ const arch_register_req_t *outreq
+ = arch_get_irn_register_req_out(node, o);
+ if (overlapping_regs(outreg, outreq, reg, in_req))
+ return false;
+ }
+ }
+
+ schedpoint = sched_prev(schedpoint);
+ }
+ return true;
+}
+