/* * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved. * * This file is part of libFirm. * * This file may be distributed and/or modified under the terms of the * GNU General Public License version 2 as published by the Free Software * Foundation and appearing in the file LICENSE.GPL included in the * packaging of this file. * * Licensees holding valid libFirm Professional Edition licenses may use * this file in accordance with the libFirm Commercial License. * Agreement provided with the Software. * * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE. */ /** * @file * @brief Performs lowering of perm nodes. Inserts copies to assure register constraints. * @author Christian Wuerdig * @date 14.12.2005 * @version $Id$ */ #include "config.h" #include #include "ircons.h" #include "debug.h" #include "xmalloc.h" #include "irnodeset.h" #include "irnodemap.h" #include "irgmod.h" #include "iredges_t.h" #include "irgwalk.h" #include "array_t.h" #include "bearch.h" #include "belower.h" #include "benode.h" #include "besched.h" #include "bestat.h" #include "bessaconstr.h" #include "beintlive_t.h" #undef KEEP_ALIVE_COPYKEEP_HACK DEBUG_ONLY(static firm_dbg_module_t *dbg;) DEBUG_ONLY(static firm_dbg_module_t *dbg_constr;) DEBUG_ONLY(static firm_dbg_module_t *dbg_permmove;) /** Associates an ir_node with it's copy and CopyKeep. */ typedef struct { ir_nodeset_t copies; /**< all non-spillable copies of this irn */ const arch_register_class_t *cls; } op_copy_assoc_t; /** Environment for constraints. */ typedef struct { ir_graph *irg; ir_nodemap_t op_set; struct obstack obst; } constraint_env_t; /** Lowering walker environment. */ typedef struct lower_env_t { ir_graph *irg; unsigned do_copy : 1; } lower_env_t; /** Holds a Perm register pair. */ typedef struct reg_pair_t { const arch_register_t *in_reg; /**< a perm IN register */ ir_node *in_node; /**< the in node to which the register belongs */ const arch_register_t *out_reg; /**< a perm OUT register */ ir_node *out_node; /**< the out node to which the register belongs */ int checked; /**< indicates whether the pair was check for cycle or not */ } reg_pair_t; typedef enum perm_type_t { PERM_CYCLE, PERM_CHAIN, PERM_SWAP, PERM_COPY } perm_type_t; /** Structure to represent cycles or chains in a Perm. */ typedef struct perm_cycle_t { const arch_register_t **elems; /**< the registers in the cycle */ int n_elems; /**< number of elements in the cycle */ perm_type_t type; /**< type (CHAIN or CYCLE) */ } perm_cycle_t; /** returns the number register pairs marked as checked. */ static int get_n_unchecked_pairs(reg_pair_t const *const pairs, int const n) { int n_unchecked = 0; int i; for (i = 0; i < n; i++) { if (!pairs[i].checked) n_unchecked++; } return n_unchecked; } /** * Gets the node corresponding to an IN register from an array of register pairs. * NOTE: The given registers pairs and the register to look for must belong * to the same register class. * * @param pairs The array of register pairs * @param n The number of pairs * @param reg The register to look for * @return The corresponding node or NULL if not found */ static ir_node *get_node_for_in_register(reg_pair_t *pairs, int n, const arch_register_t *reg) { int i; for (i = 0; i < n; i++) { /* in register matches */ if (pairs[i].in_reg->index == reg->index) return pairs[i].in_node; } return NULL; } /** * Gets the node corresponding to an OUT register from an array of register pairs. * NOTE: The given registers pairs and the register to look for must belong * to the same register class. * * @param pairs The array of register pairs * @param n The number of pairs * @param reg The register to look for * @return The corresponding node or NULL if not found */ static ir_node *get_node_for_out_register(reg_pair_t *pairs, int n, const arch_register_t *reg) { int i; for (i = 0; i < n; i++) { /* out register matches */ if (pairs[i].out_reg->index == reg->index) return pairs[i].out_node; } return NULL; } /** * Gets the index in the register pair array where the in register * corresponds to reg_idx. * * @param pairs The array of register pairs * @param n The number of pairs * @param reg The register index to look for * * @return The corresponding index in pairs or -1 if not found */ static int get_pairidx_for_in_regidx(reg_pair_t *pairs, int n, unsigned reg_idx) { int i; for (i = 0; i < n; i++) { /* in register matches */ if (pairs[i].in_reg->index == reg_idx) return i; } return -1; } /** * Gets the index in the register pair array where the out register * corresponds to reg_idx. * * @param pairs The array of register pairs * @param n The number of pairs * @param reg The register index to look for * * @return The corresponding index in pairs or -1 if not found */ static int get_pairidx_for_out_regidx(reg_pair_t *pairs, int n, unsigned reg_idx) { int i; for (i = 0; i < n; i++) { /* out register matches */ if (pairs[i].out_reg->index == reg_idx) return i; } return -1; } /** * Gets an array of register pairs and tries to identify a cycle or chain * starting at position start. * * @param cycle Variable to hold the cycle * @param pairs Array of register pairs * @param n length of the pairs array * @param start Index to start * * @return The cycle or chain */ static void get_perm_cycle(perm_cycle_t *const cycle, reg_pair_t *const pairs, int const n, int start) { int head = pairs[start].in_reg->index; int cur_idx = pairs[start].out_reg->index; int const n_pairs_todo = get_n_unchecked_pairs(pairs, n); perm_type_t cycle_tp = PERM_CYCLE; int idx; /* We could be right in the middle of a chain, so we need to find the start */ while (head != cur_idx) { /* goto previous register in cycle or chain */ int const cur_pair_idx = get_pairidx_for_out_regidx(pairs, n, head); if (cur_pair_idx < 0) { cycle_tp = PERM_CHAIN; break; } else { head = pairs[cur_pair_idx].in_reg->index; start = cur_pair_idx; } } /* assume worst case: all remaining pairs build a cycle or chain */ cycle->elems = XMALLOCNZ(const arch_register_t*, n_pairs_todo * 2); cycle->n_elems = 2; /* initial number of elements is 2 */ cycle->elems[0] = pairs[start].in_reg; cycle->elems[1] = pairs[start].out_reg; cycle->type = cycle_tp; cur_idx = pairs[start].out_reg->index; idx = 2; /* check for cycle or end of a chain */ while (cur_idx != head) { /* goto next register in cycle or chain */ int const cur_pair_idx = get_pairidx_for_in_regidx(pairs, n, cur_idx); if (cur_pair_idx < 0) break; cur_idx = pairs[cur_pair_idx].out_reg->index; /* it's not the first element: insert it */ if (cur_idx != head) { cycle->elems[idx++] = pairs[cur_pair_idx].out_reg; cycle->n_elems++; } else { /* we are there where we started -> CYCLE */ cycle->type = PERM_CYCLE; } } /* mark all pairs having one in/out register with cycle in common as checked */ for (idx = 0; idx < cycle->n_elems; idx++) { int cur_pair_idx; cur_pair_idx = get_pairidx_for_in_regidx(pairs, n, cycle->elems[idx]->index); if (cur_pair_idx >= 0) pairs[cur_pair_idx].checked = 1; cur_pair_idx = get_pairidx_for_out_regidx(pairs, n, cycle->elems[idx]->index); if (cur_pair_idx >= 0) pairs[cur_pair_idx].checked = 1; } } /** * Lowers a perm node. Resolves cycles and creates a bunch of * copy and swap operations to permute registers. * Note: The caller of this function has to make sure, that irn * is a Perm node. * * @param irn The perm node * @param block The block the perm node belongs to * @param env The lowerer environment */ static void lower_perm_node(ir_node *irn, lower_env_t *env) { const arch_register_class_t *const reg_class = arch_get_irn_register(get_irn_n(irn, 0))->reg_class; ir_node *const block = get_nodes_block(irn); int const arity = get_irn_arity(irn); reg_pair_t *const pairs = ALLOCAN(reg_pair_t, arity); int keep_perm = 0; int do_copy = env->do_copy; /* Get the schedule predecessor node to the perm. * NOTE: This works with auto-magic. If we insert the new copy/exchange * nodes after this node, everything should be ok. */ ir_node * sched_point = sched_prev(irn); const ir_edge_t * edge; const ir_edge_t * next; int n; int i; DBG((dbg, LEVEL_1, "perm: %+F, sched point is %+F\n", irn, sched_point)); assert(sched_point && "Perm is not scheduled or has no predecessor"); assert(arity == get_irn_n_edges(irn) && "perm's in and out numbers different"); /* build the list of register pairs (in, out) */ n = 0; foreach_out_edge_safe(irn, edge, next) { ir_node *const out = get_edge_src_irn(edge); long const pn = get_Proj_proj(out); ir_node *const in = get_irn_n(irn, pn); arch_register_t const *const in_reg = arch_get_irn_register(in); arch_register_t const *const out_reg = arch_get_irn_register(out); reg_pair_t * pair; if (in_reg == out_reg) { DBG((dbg, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n", irn, in, out, out_reg->name)); exchange(out, in); continue; } pair = &pairs[n++]; pair->in_node = in; pair->in_reg = in_reg; pair->out_node = out; pair->out_reg = out_reg; pair->checked = 0; } DBG((dbg, LEVEL_1, "%+F has %d unresolved constraints\n", irn, n)); /* Set do_copy to 0 if it's on but we have no free register */ /* TODO check for free register */ if (do_copy) { do_copy = 0; } /* check for cycles and chains */ while (get_n_unchecked_pairs(pairs, n) > 0) { perm_cycle_t cycle; int j; /* go to the first not-checked pair */ for (i = 0; pairs[i].checked; ++i) {} get_perm_cycle(&cycle, pairs, n, i); DB((dbg, LEVEL_1, "%+F: following %s created:\n ", irn, cycle.type == PERM_CHAIN ? "chain" : "cycle")); for (j = 0; j < cycle.n_elems; j++) { DB((dbg, LEVEL_1, " %s", cycle.elems[j]->name)); } DB((dbg, LEVEL_1, "\n")); if (cycle.type == PERM_CYCLE && arity == 2) { /* We don't need to do anything if we have a Perm with two elements * which represents a cycle, because those nodes already represent * exchange nodes */ keep_perm = 1; } else { /* TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and * insert copy to/from it before/after the copy cascade (this * reduces the cycle into a chain) */ /* build copy/swap nodes from back to front */ for (i = cycle.n_elems - 2; i >= 0; i--) { ir_node *arg1 = get_node_for_in_register(pairs, n, cycle.elems[i]); ir_node *arg2 = get_node_for_in_register(pairs, n, cycle.elems[i + 1]); ir_node *res1 = get_node_for_out_register(pairs, n, cycle.elems[i]); ir_node *res2 = get_node_for_out_register(pairs, n, cycle.elems[i + 1]); /* If we have a cycle and don't copy: we need to create exchange * nodes * NOTE: An exchange node is a perm node with 2 INs and 2 OUTs * IN_1 = in node with register i * IN_2 = in node with register i + 1 * OUT_1 = out node with register i + 1 * OUT_2 = out node with register i */ if (cycle.type == PERM_CYCLE && !do_copy) { ir_node *in[2]; ir_node *cpyxchg; in[0] = arg1; in[1] = arg2; /* At this point we have to handle the following problem: * * If we have a cycle with more than two elements, then this * could correspond to the following Perm node: * * +----+ +----+ +----+ * | r1 | | r2 | | r3 | * +-+--+ +-+--+ +--+-+ * | | | * | | | * +-+--------+---------+-+ * | Perm | * +-+--------+---------+-+ * | | | * | | | * +-+--+ +-+--+ +--+-+ * |Proj| |Proj| |Proj| * | r2 | | r3 | | r1 | * +----+ +----+ +----+ * * This node is about to be split up into two 2x Perm's for * which we need 4 Proj's and the one additional Proj of the * first Perm has to be one IN of the second. So in general * we need to create one additional Proj for each "middle" * Perm and set this to one in node of the successor Perm. */ DBG((dbg, LEVEL_1, "%+F creating exchange node (%+F, %s) and (%+F, %s) with\n", irn, arg1, cycle.elems[i]->name, arg2, cycle.elems[i + 1]->name)); DBG((dbg, LEVEL_1, "%+F (%+F, %s) and (%+F, %s)\n", irn, res1, cycle.elems[i]->name, res2, cycle.elems[i + 1]->name)); cpyxchg = be_new_Perm(reg_class, block, 2, in); if (i > 0) { /* cycle is not done yet */ int pidx = get_pairidx_for_in_regidx(pairs, n, cycle.elems[i]->index); /* create intermediate proj */ res1 = new_r_Proj(cpyxchg, get_irn_mode(res1), 0); /* set as in for next Perm */ pairs[pidx].in_node = res1; } set_Proj_pred(res2, cpyxchg); set_Proj_proj(res2, 0); set_Proj_pred(res1, cpyxchg); set_Proj_proj(res1, 1); arch_set_irn_register(res2, cycle.elems[i + 1]); arch_set_irn_register(res1, cycle.elems[i]); /* insert the copy/exchange node in schedule after the magic schedule node (see above) */ sched_add_after(skip_Proj(sched_point), cpyxchg); DB((dbg, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point)); /* set the new scheduling point */ sched_point = res1; } else { ir_node *cpyxchg; DB((dbg, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n", irn, arg1, cycle.elems[i]->name, res2, cycle.elems[i + 1]->name)); cpyxchg = be_new_Copy(reg_class, block, arg1); arch_set_irn_register(cpyxchg, cycle.elems[i + 1]); /* exchange copy node and proj */ exchange(res2, cpyxchg); /* insert the copy/exchange node in schedule after the magic schedule node (see above) */ sched_add_after(skip_Proj(sched_point), cpyxchg); /* set the new scheduling point */ sched_point = cpyxchg; } } } free((void*)cycle.elems); } /* remove the perm from schedule */ if (!keep_perm) { sched_remove(irn); kill_node(irn); } } static int has_irn_users(const ir_node *irn) { return get_irn_out_edge_first_kind(irn, EDGE_KIND_NORMAL) != 0; } static ir_node *find_copy(ir_node *irn, ir_node *op) { ir_node *cur_node; for (cur_node = irn;;) { cur_node = sched_prev(cur_node); if (! be_is_Copy(cur_node)) return NULL; if (be_get_Copy_op(cur_node) == op && arch_irn_is(cur_node, dont_spill)) return cur_node; } } static void gen_assure_different_pattern(ir_node *irn, ir_node *other_different, constraint_env_t *env) { ir_nodemap_t *op_set; ir_node *block; const arch_register_class_t *cls; ir_node *keep, *cpy; op_copy_assoc_t *entry; if (arch_irn_is_ignore(other_different) || !mode_is_datab(get_irn_mode(other_different))) { DB((dbg_constr, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn)); return; } op_set = &env->op_set; block = get_nodes_block(irn); cls = arch_get_irn_reg_class_out(other_different); /* 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 */ /* check if already exists such a copy in the schedule immediately before */ cpy = find_copy(skip_Proj(irn), other_different); if (! cpy) { cpy = be_new_Copy(cls, block, other_different); arch_irn_set_flags(cpy, arch_irn_flags_dont_spill); DB((dbg_constr, LEVEL_1, "created non-spillable %+F for value %+F\n", cpy, other_different)); } else { DB((dbg_constr, LEVEL_1, "using already existing %+F for value %+F\n", cpy, other_different)); } /* Add the Keep resp. CopyKeep and reroute the users */ /* of the other_different irn in case of CopyKeep. */ if (has_irn_users(other_different)) { keep = be_new_CopyKeep_single(cls, block, cpy, irn, get_irn_mode(other_different)); be_node_set_reg_class_in(keep, 1, cls); } else { ir_node *in[2]; in[0] = irn; in[1] = cpy; keep = be_new_Keep(block, 2, in); } DB((dbg_constr, LEVEL_1, "created %+F(%+F, %+F)\n\n", keep, irn, cpy)); /* insert copy and keep into schedule */ assert(sched_is_scheduled(irn) && "need schedule to assure constraints"); if (! sched_is_scheduled(cpy)) sched_add_before(skip_Proj(irn), cpy); sched_add_after(skip_Proj(irn), keep); /* insert the other different and it's copies into the map */ entry = (op_copy_assoc_t*)ir_nodemap_get(op_set, other_different); if (! entry) { entry = OALLOC(&env->obst, op_copy_assoc_t); entry->cls = cls; ir_nodeset_init(&entry->copies); ir_nodemap_insert(op_set, other_different, entry); } /* insert copy */ ir_nodeset_insert(&entry->copies, cpy); /* insert keep in case of CopyKeep */ if (be_is_CopyKeep(keep)) ir_nodeset_insert(&entry->copies, keep); } /** * Checks if node has a must_be_different constraint in output and adds a Keep * then to assure the constraint. * * @param irn the node to check * @param skipped_irn if irn is a Proj node, its predecessor, else irn * @param env the constraint environment */ static void assure_different_constraints(ir_node *irn, ir_node *skipped_irn, constraint_env_t *env) { const arch_register_req_t *req = arch_get_register_req_out(irn); if (arch_register_req_is(req, must_be_different)) { const unsigned other = req->other_different; int i; if (arch_register_req_is(req, should_be_same)) { const unsigned same = req->other_same; if (is_po2(other) && is_po2(same)) { int idx_other = ntz(other); int idx_same = ntz(same); /* * We can safely ignore a should_be_same x must_be_different y * IFF both inputs are equal! */ if (get_irn_n(skipped_irn, idx_other) == get_irn_n(skipped_irn, idx_same)) { return; } } } for (i = 0; 1U << i <= other; ++i) { if (other & (1U << i)) { ir_node *different_from = get_irn_n(skipped_irn, i); gen_assure_different_pattern(irn, different_from, env); } } } } /** * Calls the functions to assure register constraints. * * @param block The block to be checked * @param walk_env The walker environment */ static void assure_constraints_walker(ir_node *block, void *walk_env) { ir_node *irn; constraint_env_t *env = (constraint_env_t*)walk_env; sched_foreach_reverse(block, irn) { ir_mode *mode = get_irn_mode(irn); if (mode == mode_T) { const ir_edge_t *edge; foreach_out_edge(irn, edge) { ir_node *proj = get_edge_src_irn(edge); mode = get_irn_mode(proj); if (mode_is_datab(mode)) assure_different_constraints(proj, irn, env); } } else if (mode_is_datab(mode)) { assure_different_constraints(irn, irn, env); } } } /** * Melt all copykeeps pointing to the same node * (or Projs of the same node), copying the same operand. */ static void melt_copykeeps(constraint_env_t *cenv) { ir_nodemap_iterator_t map_iter; ir_nodemap_entry_t map_entry; /* for all */ foreach_ir_nodemap(&cenv->op_set, map_entry, map_iter) { op_copy_assoc_t *entry = (op_copy_assoc_t*)map_entry.data; int idx, num_ck; ir_node *cp; struct obstack obst; ir_nodeset_iterator_t iter; ir_node **ck_arr, **melt_arr; obstack_init(&obst); /* collect all copykeeps */ num_ck = idx = 0; foreach_ir_nodeset(&entry->copies, cp, iter) { if (be_is_CopyKeep(cp)) { obstack_grow(&obst, &cp, sizeof(cp)); ++num_ck; } #ifdef KEEP_ALIVE_COPYKEEP_HACK else { set_irn_mode(cp, mode_ANY); keep_alive(cp); } #endif /* KEEP_ALIVE_COPYKEEP_HACK */ } /* compare each copykeep with all other copykeeps */ ck_arr = (ir_node **)obstack_finish(&obst); for (idx = 0; idx < num_ck; ++idx) { ir_node *ref, *ref_mode_T; if (ck_arr[idx]) { int j, n_melt; ir_node **new_ck_in; ir_node *new_ck; ir_node *sched_pt = NULL; n_melt = 1; ref = ck_arr[idx]; ref_mode_T = skip_Proj(get_irn_n(ref, 1)); obstack_grow(&obst, &ref, sizeof(ref)); DB((dbg_constr, LEVEL_1, "Trying to melt %+F:\n", ref)); /* check for copykeeps pointing to the same mode_T node as the reference copykeep */ for (j = 0; j < num_ck; ++j) { ir_node *cur_ck = ck_arr[j]; if (j != idx && cur_ck && skip_Proj(get_irn_n(cur_ck, 1)) == ref_mode_T) { obstack_grow(&obst, &cur_ck, sizeof(cur_ck)); ir_nodeset_remove(&entry->copies, cur_ck); DB((dbg_constr, LEVEL_1, "\t%+F\n", cur_ck)); ck_arr[j] = NULL; ++n_melt; sched_remove(cur_ck); } } ck_arr[idx] = NULL; /* check, if we found some candidates for melting */ if (n_melt == 1) { DB((dbg_constr, LEVEL_1, "\tno candidate found\n")); continue; } ir_nodeset_remove(&entry->copies, ref); sched_remove(ref); melt_arr = (ir_node **)obstack_finish(&obst); /* melt all found copykeeps */ NEW_ARR_A(ir_node *, new_ck_in, n_melt); for (j = 0; j < n_melt; ++j) { new_ck_in[j] = get_irn_n(melt_arr[j], 1); /* now, we can kill the melted keep, except the */ /* ref one, we still need some information */ if (melt_arr[j] != ref) kill_node(melt_arr[j]); } #ifdef KEEP_ALIVE_COPYKEEP_HACK new_ck = be_new_CopyKeep(entry->cls, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, mode_ANY); keep_alive(new_ck); #else new_ck = be_new_CopyKeep(entry->cls, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, get_irn_mode(ref)); #endif /* KEEP_ALIVE_COPYKEEP_HACK */ /* set register class for all kept inputs */ for (j = 1; j <= n_melt; ++j) be_node_set_reg_class_in(new_ck, j, entry->cls); ir_nodeset_insert(&entry->copies, new_ck); /* find scheduling point */ sched_pt = ref_mode_T; do { /* just walk along the schedule until a non-Keep/CopyKeep node is found */ sched_pt = sched_next(sched_pt); } while (be_is_Keep(sched_pt) || be_is_CopyKeep(sched_pt)); sched_add_before(sched_pt, new_ck); DB((dbg_constr, LEVEL_1, "created %+F, scheduled before %+F\n", new_ck, sched_pt)); /* finally: kill the reference copykeep */ kill_node(ref); } } obstack_free(&obst, NULL); } } void assure_constraints(ir_graph *irg) { constraint_env_t cenv; ir_nodemap_iterator_t map_iter; ir_nodemap_entry_t map_entry; FIRM_DBG_REGISTER(dbg_constr, "firm.be.lower.constr"); cenv.irg = irg; ir_nodemap_init(&cenv.op_set); obstack_init(&cenv.obst); irg_block_walk_graph(irg, NULL, assure_constraints_walker, &cenv); /* melt copykeeps, pointing to projs of */ /* the same mode_T node and keeping the */ /* same operand */ melt_copykeeps(&cenv); /* for all */ foreach_ir_nodemap(&cenv.op_set, map_entry, map_iter) { op_copy_assoc_t *entry = (op_copy_assoc_t*)map_entry.data; size_t n = ir_nodeset_size(&entry->copies); ir_node **nodes = ALLOCAN(ir_node*, n); ir_node *cp; ir_nodeset_iterator_t iter; be_ssa_construction_env_t senv; /* put the node in an array */ DBG((dbg_constr, LEVEL_1, "introduce copies for %+F ", map_entry.node)); /* collect all copies */ n = 0; foreach_ir_nodeset(&entry->copies, cp, iter) { nodes[n++] = cp; DB((dbg_constr, LEVEL_1, ", %+F ", cp)); } DB((dbg_constr, LEVEL_1, "\n")); /* introduce the copies for the operand and it's copies */ be_ssa_construction_init(&senv, irg); be_ssa_construction_add_copy(&senv, map_entry.node); be_ssa_construction_add_copies(&senv, nodes, n); be_ssa_construction_fix_users(&senv, map_entry.node); be_ssa_construction_destroy(&senv); /* Could be that not all CopyKeeps are really needed, */ /* so we transform unnecessary ones into Keeps. */ foreach_ir_nodeset(&entry->copies, cp, iter) { if (be_is_CopyKeep(cp) && get_irn_n_edges(cp) < 1) { int n = get_irn_arity(cp); ir_node *keep; keep = be_new_Keep(get_nodes_block(cp), n, get_irn_in(cp) + 1); sched_add_before(cp, keep); /* Set all ins (including the block) of the CopyKeep BAD to keep the verifier happy. */ sched_remove(cp); kill_node(cp); } } ir_nodeset_destroy(&entry->copies); } ir_nodemap_destroy(&cenv.op_set); obstack_free(&cenv.obst, NULL); be_liveness_invalidate(be_get_irg_liveness(irg)); } /** * Push nodes that do not need to be permed through the Perm. * This is commonly a reload cascade at block ends. * @note This routine needs interference. * @note Probably, we can implement it a little more efficient. * Especially searching the frontier lazily might be better. * * @param perm The perm * @param env The lowerer environment * * @return 1, if there is something left to perm over. * 0, if removed the complete perm. */ static int push_through_perm(ir_node *perm) { ir_graph *irg = get_irn_irg(perm); ir_node *bl = get_nodes_block(perm); ir_node *node; int arity = get_irn_arity(perm); int *map; int *proj_map; bitset_t *moved = bitset_alloca(arity); int n_moved; int new_size; ir_node *frontier = bl; ir_node *irn; int i, n; /* get some Proj and find out the register class of that Proj. */ const ir_edge_t *edge = get_irn_out_edge_first_kind(perm, EDGE_KIND_NORMAL); ir_node *one_proj = get_edge_src_irn(edge); const arch_register_class_t *cls = arch_get_irn_reg_class_out(one_proj); assert(is_Proj(one_proj)); DB((dbg_permmove, LEVEL_1, "perm move %+F irg %+F\n", perm, irg)); /* Find the point in the schedule after which the * potentially movable nodes must be defined. * A Perm will only be pushed up to first instruction * which lets an operand of itself die. * If we would allow to move the Perm above this instruction, * the former dead operand would be live now at the point of * the Perm, increasing the register pressure by one. */ sched_foreach_reverse_from(sched_prev(perm), irn) { for (i = get_irn_arity(irn) - 1; i >= 0; --i) { ir_node *op = get_irn_n(irn, i); be_lv_t *lv = be_get_irg_liveness(irg); if (arch_irn_consider_in_reg_alloc(cls, op) && !be_values_interfere(lv, op, one_proj)) { frontier = irn; goto found_front; } } } found_front: DB((dbg_permmove, LEVEL_2, "\tfrontier: %+F\n", frontier)); node = sched_prev(perm); n_moved = 0; while (!sched_is_begin(node)) { const arch_register_req_t *req; int input = -1; ir_node *proj; /* search if node is a INPUT of Perm */ foreach_out_edge(perm, edge) { ir_node *out = get_edge_src_irn(edge); int pn = get_Proj_proj(out); ir_node *in = get_irn_n(perm, pn); if (node == in) { proj = out; input = pn; break; } } /* it wasn't an input to the perm, we can't do anything more */ if (input < 0) break; if (!sched_comes_after(frontier, node)) break; if (arch_irn_is(node, modify_flags)) break; req = arch_get_register_req_out(node); if (req->type != arch_register_req_type_normal) break; for (i = get_irn_arity(node) - 1; i >= 0; --i) { ir_node *opop = get_irn_n(node, i); if (arch_irn_consider_in_reg_alloc(cls, opop)) { break; } } if (i >= 0) break; DBG((dbg_permmove, LEVEL_2, "\tmoving %+F after %+F, killing %+F\n", node, perm, proj)); /* move the movable node in front of the Perm */ sched_remove(node); sched_add_after(perm, node); /* give it the proj's register */ arch_set_irn_register(node, arch_get_irn_register(proj)); /* reroute all users of the proj to the moved node. */ exchange(proj, node); bitset_set(moved, input); n_moved++; node = sched_prev(node); } /* well, we could not push anything through the perm */ if (n_moved == 0) return 1; new_size = arity - n_moved; if (new_size == 0) { sched_remove(perm); kill_node(perm); return 0; } map = ALLOCAN(int, new_size); proj_map = ALLOCAN(int, arity); memset(proj_map, -1, sizeof(proj_map[0])); n = 0; for (i = 0; i < arity; ++i) { if (bitset_is_set(moved, i)) continue; map[n] = i; proj_map[i] = n; n++; } assert(n == new_size); foreach_out_edge(perm, edge) { ir_node *proj = get_edge_src_irn(edge); int pn = get_Proj_proj(proj); pn = proj_map[pn]; assert(pn >= 0); set_Proj_proj(proj, pn); } be_Perm_reduce(perm, new_size, map); return 1; } /** * Calls the corresponding lowering function for the node. * * @param irn The node to be checked for lowering * @param walk_env The walker environment */ static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) { int perm_stayed; if (!be_is_Perm(irn)) return; perm_stayed = push_through_perm(irn); if (perm_stayed) lower_perm_node(irn, (lower_env_t*)walk_env); } void lower_nodes_after_ra(ir_graph *irg, int do_copy) { lower_env_t env; FIRM_DBG_REGISTER(dbg, "firm.be.lower"); FIRM_DBG_REGISTER(dbg_permmove, "firm.be.lower.permmove"); env.irg = irg; env.do_copy = do_copy; /* we will need interference */ be_liveness_assure_chk(be_get_irg_liveness(irg)); irg_walk_graph(irg, NULL, lower_nodes_after_ra_walker, &env); }