+/**
+ * Tries to create Pops from Load, IncSP combinations.
+ * The Loads are replaced by Pops, the IncSP is modified
+ * (possibly into IncSP 0, but not removed).
+ */
+static void peephole_Load_IncSP_to_pop(ir_node *irn)
+{
+ const arch_register_t *esp = &ia32_gp_regs[REG_ESP];
+ int i, maxslot, inc_ofs, ofs;
+ ir_node *node, *pred_sp, *block;
+ ir_node *loads[MAXPUSH_OPTIMIZE];
+ ir_graph *irg;
+ unsigned regmask = 0;
+ unsigned copymask = ~0;
+
+ memset(loads, 0, sizeof(loads));
+ assert(be_is_IncSP(irn));
+
+ inc_ofs = -be_get_IncSP_offset(irn);
+ if (inc_ofs < 4)
+ return;
+
+ /*
+ * We first walk the schedule before the IncSP node as long as we find
+ * suitable Loads that could be transformed to a Pop.
+ * We save them into the stores array which is sorted by the frame offset/4
+ * attached to the node
+ */
+ maxslot = -1;
+ pred_sp = be_get_IncSP_pred(irn);
+ for (node = sched_prev(irn); !sched_is_end(node); node = sched_prev(node)) {
+ int offset;
+ int loadslot;
+ const arch_register_t *sreg, *dreg;
+
+ /* it has to be a Load */
+ if (!is_ia32_Load(node)) {
+ if (be_is_Copy(node)) {
+ if (!mode_needs_gp_reg(get_irn_mode(node))) {
+ /* not a GP copy, ignore */
+ continue;
+ }
+ dreg = arch_get_irn_register(node);
+ sreg = arch_get_irn_register(be_get_Copy_op(node));
+ if (regmask & copymask & (1 << sreg->index)) {
+ break;
+ }
+ if (regmask & copymask & (1 << dreg->index)) {
+ break;
+ }
+ /* we CAN skip Copies if neither the destination nor the source
+ * is not in our regmask, ie none of our future Pop will overwrite it */
+ regmask |= (1 << dreg->index) | (1 << sreg->index);
+ copymask &= ~((1 << dreg->index) | (1 << sreg->index));
+ continue;
+ }
+ break;
+ }
+
+ /* we can handle only GP loads */
+ if (!mode_needs_gp_reg(get_ia32_ls_mode(node)))
+ continue;
+
+ /* it has to use our predecessor sp value */
+ if (get_irn_n(node, n_ia32_base) != pred_sp) {
+ /* it would be ok if this load does not use a Pop result,
+ * but we do not check this */
+ break;
+ }
+
+ /* should have NO index */
+ if (!is_ia32_NoReg_GP(get_irn_n(node, n_ia32_index)))
+ break;
+
+ offset = get_ia32_am_offs_int(node);
+ /* we should NEVER access uninitialized stack BELOW the current SP */
+ assert(offset >= 0);
+
+ /* storing at half-slots is bad */
+ if ((offset & 3) != 0)
+ break;
+
+ if (offset < 0 || offset >= MAXPUSH_OPTIMIZE * 4)
+ continue;
+ /* ignore those outside the possible windows */
+ if (offset > inc_ofs - 4)
+ continue;
+ loadslot = offset >> 2;
+
+ /* loading from the same slot twice is bad (and shouldn't happen...) */
+ if (loads[loadslot] != NULL)
+ break;
+
+ dreg = arch_get_irn_register(node);
+ if (regmask & (1 << dreg->index)) {
+ /* this register is already used */
+ break;
+ }
+ regmask |= 1 << dreg->index;
+
+ loads[loadslot] = node;
+ if (loadslot > maxslot)
+ maxslot = loadslot;
+ }
+
+ if (maxslot < 0)
+ return;
+
+ /* find the first slot */
+ for (i = maxslot; i >= 0; --i) {
+ ir_node *load = loads[i];
+
+ if (load == NULL)
+ break;
+ }
+
+ ofs = inc_ofs - (maxslot + 1) * 4;
+ inc_ofs = (i+1) * 4;
+
+ /* create a new IncSP if needed */
+ block = get_nodes_block(irn);
+ irg = cg->irg;
+ if (inc_ofs > 0) {
+ pred_sp = be_new_IncSP(esp, irg, block, pred_sp, -inc_ofs, be_get_IncSP_align(irn));
+ sched_add_before(irn, pred_sp);
+ }
+
+ /* walk through the Loads and create Pops for them */
+ for (++i; i <= maxslot; ++i) {
+ ir_node *load = loads[i];
+ ir_node *mem, *pop;
+ const ir_edge_t *edge, *tmp;
+ const arch_register_t *reg;
+
+ mem = get_irn_n(load, n_ia32_mem);
+ reg = arch_get_irn_register(load);
+
+ pop = new_rd_ia32_Pop(get_irn_dbg_info(load), irg, block, mem, pred_sp);
+ arch_set_irn_register(pop, reg);
+
+ copy_mark(load, pop);
+
+ /* create stackpointer Proj */
+ pred_sp = new_r_Proj(irg, block, pop, mode_Iu, pn_ia32_Pop_stack);
+ arch_set_irn_register(pred_sp, esp);
+
+ sched_add_before(irn, pop);
+
+ /* rewire now */
+ foreach_out_edge_safe(load, edge, tmp) {
+ ir_node *proj = get_edge_src_irn(edge);
+
+ set_Proj_pred(proj, pop);
+ }
+
+ /* we can remove the Load now */
+ sched_remove(load);
+ kill_node(load);
+ }
+
+ be_set_IncSP_offset(irn, -ofs);
+ be_set_IncSP_pred(irn, pred_sp);
+}
+
+