2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Performs SSA-Destruction.
23 * @author Daniel Grund
34 #include "iredges_t.h"
42 #include "bechordal_t.h"
47 #include "bestatevent.h"
49 #include "beintlive_t.h"
51 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
53 #define get_reg(irn) arch_get_irn_register(irn)
54 #define set_reg(irn, reg) arch_set_irn_register(irn, reg)
56 static void clear_link(ir_node *irn, void *data)
59 set_irn_link(irn, NULL);
63 * For each block build a linked list of phis that
65 * - have the current register class
66 * The list is rooted at get_irn_link(BB).
68 static void collect_phis_walker(ir_node *irn, void *data)
70 be_chordal_env_t *env = data;
71 if (is_Phi(irn) && chordal_has_class(env, irn)) {
72 ir_node *bl = get_nodes_block(irn);
73 set_irn_link(irn, get_irn_link(bl));
74 set_irn_link(bl, irn);
79 * This struct represents a Proj for a Perm.
80 * It records the argument in the Perm and the corresponding Proj of the
84 ir_node *arg; /**< The phi argument to make the Proj for. */
85 int pos; /**< The proj number the Proj will get.
86 This also denotes the position of @p arg
87 in the in array of the Perm. */
88 ir_node *proj; /**< The proj created for @p arg. */
91 static int cmp_perm_proj(const void *a, const void *b, size_t n)
93 const perm_proj_t *p = a;
94 const perm_proj_t *q = b;
97 return !(p->arg == q->arg);
100 typedef struct insert_all_perms_env_t {
101 be_chordal_env_t *chordal_env;
103 } insert_all_perms_env_t;
106 * Insert Perms in all predecessors of a block containing a phi
108 static void insert_all_perms_walker(ir_node *bl, void *data)
110 insert_all_perms_env_t *env = data;
111 be_chordal_env_t *chordal_env = env->chordal_env;
112 pmap *perm_map = env->perm_map;
113 be_lv_t *lv = chordal_env->birg->lv;
116 assert(is_Block(bl));
118 /* If the link flag is NULL, this block has no phis. */
119 if (!get_irn_link(bl))
122 /* Look at all predecessors of the phi block */
123 for (i = 0, n = get_irn_arity(bl); i < n; ++i) {
124 ir_node *phi, *perm, *insert_after, **in;
126 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
127 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
130 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
133 * Note that all phis in the list are in the same
134 * register class by construction.
136 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
137 ir_node *arg = get_irn_n(phi, i);
138 const arch_register_req_t *req = arch_get_register_req_out(arg);
142 if (req->type & arch_register_req_type_ignore)
145 hash = hash_irn(arg);
147 pp = set_find(arg_set, &templ, sizeof(templ), hash);
150 * If a proj_perm_t entry has not been made in the argument set,
151 * create one. The only restriction is, that the phi argument
152 * may not be live in at the current block, since this argument
153 * interferes with the phi and must thus not be member of a
154 * Perm. A copy will be inserted for this argument later on.
156 if (!pp && !be_is_live_in(lv, bl, arg)) {
157 templ.pos = n_projs++;
158 set_insert(arg_set, &templ, sizeof(templ), hash);
165 * Create a new Perm with the arguments just collected
166 * above in the arg_set and insert it into the schedule.
168 in = XMALLOCN(ir_node*, n_projs);
169 for (pp = set_first(arg_set); pp; pp = set_next(arg_set))
170 in[pp->pos] = pp->arg;
172 perm = be_new_Perm(chordal_env->cls, pred_bl, n_projs, in);
173 be_stat_ev("phi_perm", n_projs);
175 insert_after = sched_skip(sched_last(pred_bl), 0, sched_skip_cf_predicator, NULL);
176 sched_add_after(insert_after, perm);
179 * Make the Projs for the Perm and insert into schedule.
180 * Register allocation is copied from the former phi
181 * arguments to the projs (new phi arguments).
184 for (pp = set_first(arg_set); pp; pp = set_next(arg_set)) {
185 ir_node *proj = new_r_Proj(pred_bl, perm, get_irn_mode(pp->arg), pp->pos);
187 assert(get_reg(pp->arg));
188 set_reg(proj, get_reg(pp->arg));
190 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", get_reg(pp->arg)->name, pp->arg, pp->proj));
194 * Set the phi nodes to their new arguments: The Projs of the Perm
196 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
199 templ.arg = get_irn_n(phi, i);
200 pp = set_find(arg_set, &templ, sizeof(templ), hash_irn(templ.arg));
202 /* If not found, it was an interfering argument */
204 set_irn_n(phi, i, pp->proj);
205 be_liveness_introduce(lv, pp->proj);
209 /* update the liveness of the Perm's operands. It might be changed. */
212 for (i = 0; i < n_projs; ++i)
213 be_liveness_update(lv, in[i]);
217 /* register in perm map */
218 pmap_insert(perm_map, pred_bl, perm);
225 #define is_pinned(irn) (get_irn_link(irn))
226 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
227 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
230 * Adjusts the register allocation for the (new) phi-operands
231 * and insert duplicates iff necessary.
233 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data)
235 be_chordal_env_t *chordal_env = data;
236 be_lv_t *lv = chordal_env->birg->lv;
239 /* Consider all phis of this block */
240 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
241 ir_node *phi_block = get_nodes_block(phi);
242 const arch_register_t *phi_reg = get_reg(phi);
243 const arch_register_class_t *cls = phi_reg->reg_class;
247 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
249 /* process all arguments of the phi */
250 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
251 ir_node *arg = get_irn_n(phi, i);
252 const arch_register_req_t *req = arch_get_register_req_out(arg);
253 const arch_register_t *arg_reg;
256 if (req->type & arch_register_req_type_ignore)
259 arg_block = get_Block_cfgpred_block(phi_block, i);
260 arg_reg = get_reg(arg);
262 assert(arg_reg && "Register must be set while placing perms");
264 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
266 if (be_values_interfere(lv, phi, arg)) {
268 Insert a duplicate in arguments block,
269 make it the new phi arg,
271 insert it into schedule,
274 ir_node *dupl = be_new_Copy(cls, arg_block, arg);
276 /* this is commented out because it will fail in case of unknown float */
278 ir_mode *m_phi = get_irn_mode(phi), *m_dupl = get_irn_mode(dupl);
281 Conv signed <-> unsigned is killed on ia32
282 check for: (both int OR both float) AND equal mode sizes
284 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
285 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
286 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
289 set_irn_n(phi, i, dupl);
290 set_reg(dupl, phi_reg);
291 sched_add_after(sched_skip(sched_last(arg_block), 0, sched_skip_cf_predicator, NULL), dupl);
292 pin_irn(dupl, phi_block);
293 be_liveness_introduce(lv, dupl);
294 be_liveness_update(lv, arg);
295 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
296 continue; /* with next argument */
299 if (phi_reg == arg_reg) {
300 /* Phi and arg have the same register, so pin and continue */
301 pin_irn(arg, phi_block);
302 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, get_reg(arg)->name));
306 DBG((dbg, LEVEL_1, " they do not interfere\n"));
307 assert(is_Proj(arg));
309 First check if there is an other phi
311 - having arg at the current pos in its arg-list
312 - having the same color as arg
314 If found, then pin the arg (for that phi)
316 if (! is_pinned(arg)) {
319 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
321 for (other_phi = get_irn_link(phi_block); other_phi; other_phi = get_irn_link(other_phi)) {
323 assert(is_Phi(other_phi) &&
324 get_nodes_block(phi) == get_nodes_block(other_phi) &&
325 "link fields are screwed up");
327 if (get_irn_n(other_phi, i) == arg && get_reg(other_phi) == arg_reg) {
328 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, get_reg(other_phi)->name));
329 pin_irn(arg, phi_block);
335 if (is_pinned(arg)) {
337 Insert a duplicate of the original value in arguments block,
338 make it the new phi arg,
340 insert it into schedule,
343 ir_node *perm = get_Proj_pred(arg);
344 ir_node *dupl = be_new_Copy(cls, arg_block, arg);
347 /* this is commented out because it will fail in case of unknown float */
349 ir_mode *m_phi = get_irn_mode(phi);
350 ir_mode *m_dupl = get_irn_mode(dupl);
353 Conv signed <-> unsigned is killed on ia32
354 check for: (both int OR both float) AND equal mode sizes
356 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
357 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
358 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
361 set_irn_n(phi, i, dupl);
362 set_reg(dupl, phi_reg);
363 /* skip the Perm's Projs and insert the copies behind. */
364 for (ins = sched_next(perm); is_Proj(ins); ins = sched_next(ins));
365 sched_add_before(ins, dupl);
366 pin_irn(dupl, phi_block);
367 be_liveness_introduce(lv, dupl);
368 be_liveness_update(lv, arg);
369 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
372 No other phi has the same color (else arg would have been pinned),
373 so just set the register and pin
375 set_reg(arg, phi_reg);
376 pin_irn(arg, phi_block);
377 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, get_reg(arg)->name));
383 void be_ssa_destruction(be_chordal_env_t *chordal_env)
385 insert_all_perms_env_t insert_perms_env;
386 pmap *perm_map = pmap_create();
387 ir_graph *irg = chordal_env->irg;
388 be_lv_t *lv = be_assure_liveness(chordal_env->birg);
390 FIRM_DBG_REGISTER(dbg, "ir.be.ssadestr");
392 be_liveness_invalidate(lv);
394 /* create a map for fast lookup of perms: block --> perm */
395 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
397 DBG((dbg, LEVEL_1, "Placing perms...\n"));
398 insert_perms_env.chordal_env = chordal_env;
399 insert_perms_env.perm_map = perm_map;
400 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, &insert_perms_env);
402 // Matze: really needed here?
403 // Sebastian: Yes. the walker function uses interference.
404 be_liveness_invalidate(lv);
406 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
407 be_dump(irg, "-ssa_destr_perms_placed", dump_ir_block_graph_sched);
409 be_liveness_assure_chk(lv);
411 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
412 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
414 /* TODO: unfortunately updating doesn't work yet. */
415 be_liveness_invalidate(lv);
417 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
418 be_dump(irg, "-ssa_destr_regs_set", dump_ir_block_graph_sched);
420 pmap_destroy(perm_map);
423 static void ssa_destruction_check_walker(ir_node *bl, void *data)
429 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
430 const arch_register_t *phi_reg, *arg_reg;
432 phi_reg = get_reg(phi);
433 /* iterate over all args of phi */
434 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
435 ir_node *arg = get_irn_n(phi, i);
436 const arch_register_req_t *req = arch_get_register_req_out(arg);
438 if (req->type & arch_register_req_type_ignore)
441 arg_reg = get_reg(arg);
443 if (phi_reg != arg_reg) {
444 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
448 if (! is_pinned(arg)) {
449 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
456 void be_ssa_destruction_check(be_chordal_env_t *chordal_env)
458 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, NULL);