2 * Copyright (C) 1995-2007 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
36 #include "iredges_t.h"
44 #include "bechordal_t.h"
48 #include "besched_t.h"
49 #include "benodesets.h"
50 #include "bestatevent.h"
52 #include "beintlive_t.h"
54 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
56 #define get_chordal_arch(ce) ((ce)->birg->main_env->arch_env)
57 #define get_reg(irn) arch_get_irn_register(get_chordal_arch(chordal_env), irn)
58 #define set_reg(irn, reg) arch_set_irn_register(get_chordal_arch(chordal_env), irn, reg)
60 #define is_Perm(irn) (arch_irn_class_is(arch_env, irn, perm))
61 #define get_reg_cls(irn) (arch_get_irn_reg_class(arch_env, irn, -1))
62 #define is_curr_reg_class(irn) (get_reg_cls(p) == chordal_env->cls)
64 static void clear_link(ir_node *irn, void *data) {
66 set_irn_link(irn, NULL);
70 * For each block build a linked list of phis that
72 * - have the current register class
73 * The list is rooted at get_irn_link(BB).
75 static void collect_phis_walker(ir_node *irn, void *data) {
76 be_chordal_env_t *env = data;
77 if (is_Phi(irn) && chordal_has_class(env, irn)) {
78 ir_node *bl = get_nodes_block(irn);
79 set_irn_link(irn, get_irn_link(bl));
80 set_irn_link(bl, irn);
85 * This struct represents a Proj for a Perm.
86 * It records the argument in the Perm and the corresponding Proj of the
90 ir_node *arg; /**< The phi argument to make the Proj for. */
91 int pos; /**< The proj number the Proj will get.
92 This also denotes the position of @p arg
93 in the in array of the Perm. */
94 ir_node *proj; /**< The proj created for @p arg. */
97 static int cmp_perm_proj(const void *a, const void *b, size_t n) {
98 const perm_proj_t *p = a;
99 const perm_proj_t *q = b;
102 return !(p->arg == q->arg);
105 typedef struct insert_all_perms_env_t {
106 be_chordal_env_t *chordal_env;
108 } insert_all_perms_env_t;
111 * Insert Perms in all predecessors of a block containing a phi
113 static void insert_all_perms_walker(ir_node *bl, void *data) {
114 insert_all_perms_env_t *env = data;
115 be_chordal_env_t *chordal_env = env->chordal_env;
116 pmap *perm_map = env->perm_map;
117 ir_graph *irg = chordal_env->irg;
118 be_lv_t *lv = chordal_env->birg->lv;
121 assert(is_Block(bl));
123 /* If the link flag is NULL, this block has no phis. */
124 if(!get_irn_link(bl))
127 /* Look at all predecessors of the phi block */
128 for(i = 0, n = get_irn_arity(bl); i < n; ++i) {
129 ir_node *phi, *perm, *insert_after, **in;
131 set *arg_set = new_set(cmp_perm_proj, chordal_env->cls->n_regs);
132 ir_node *pred_bl = get_Block_cfgpred_block(bl, i);
135 assert(!pmap_contains(perm_map, pred_bl) && "Already permed that block");
138 * Note that all phis in the list are in the same
139 * register class by construction.
141 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
143 ir_node *arg = get_irn_n(phi, i);
144 unsigned hash = nodeset_hash(arg);
146 if (arch_irn_is(chordal_env->birg->main_env->arch_env, arg, ignore))
150 pp = set_find(arg_set, &templ, sizeof(templ), hash);
153 * If a proj_perm_t entry has not been made in the argument set,
154 * create one. The only restriction is, that the phi argument
155 * may not be live in at the current block, since this argument
156 * interferes with the phi and must thus not be member of a
157 * Perm. A copy will be inserted for this argument alter on.
159 if(!pp && !be_is_live_in(lv, bl, arg)) {
160 templ.pos = n_projs++;
161 set_insert(arg_set, &templ, sizeof(templ), hash);
168 * Create a new Perm with the arguments just collected
169 * above in the arg_set and insert it into the schedule.
171 in = xmalloc(n_projs * sizeof(in[0]));
172 for(pp = set_first(arg_set); pp; pp = set_next(arg_set))
173 in[pp->pos] = pp->arg;
175 perm = be_new_Perm(chordal_env->cls, irg, pred_bl, n_projs, in);
176 be_stat_ev("phi_perm", n_projs);
178 insert_after = sched_skip(sched_last(pred_bl), 0, sched_skip_cf_predicator, chordal_env->birg->main_env->arch_env);
179 sched_add_after(insert_after, perm);
182 * Make the Projs for the Perm and insert into schedule.
183 * Register allocation is copied from the former phi
184 * arguments to the projs (new phi arguments).
187 for(pp = set_first(arg_set); pp; pp = set_next(arg_set)) {
188 ir_node *proj = new_r_Proj(irg, pred_bl, perm, get_irn_mode(pp->arg), pp->pos);
190 assert(get_reg(pp->arg));
191 set_reg(proj, get_reg(pp->arg));
193 DBG((dbg, LEVEL_2, "Copy register assignment %s from %+F to %+F\n", get_reg(pp->arg)->name, pp->arg, pp->proj));
197 * Set the phi nodes to their new arguments: The Projs of the Perm
199 for(phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
202 templ.arg = get_irn_n(phi, i);
203 pp = set_find(arg_set, &templ, sizeof(templ), nodeset_hash(templ.arg));
205 /* If not found, it was an interfering argument */
207 set_irn_n(phi, i, pp->proj);
208 be_liveness_introduce(lv, pp->proj);
212 /* update the liveness of the Perm's operands. It might be changed. */
215 for (i = 0; i < n_projs; ++i)
216 be_liveness_update(lv, in[i]);
220 /* register in perm map */
221 pmap_insert(perm_map, pred_bl, perm);
228 #define is_pinned(irn) (get_irn_link(irn))
229 #define get_pinning_block(irn) ((ir_node *)get_irn_link(irn))
230 #define pin_irn(irn, lock) (set_irn_link(irn, lock))
233 * Adjusts the register allocation for the (new) phi-operands
234 * and insert duplicates iff necessary.
236 static void set_regs_or_place_dupls_walker(ir_node *bl, void *data) {
237 be_chordal_env_t *chordal_env = data;
238 be_lv_t *lv = chordal_env->birg->lv;
241 /* Consider all phis of this block */
242 for (phi = get_irn_link(bl); phi; phi = get_irn_link(phi)) {
244 ir_node *arg, *phi_block, *arg_block;
245 const arch_register_t *phi_reg, *arg_reg;
246 const arch_register_class_t *cls;
248 assert(is_Phi(phi) && "Can only handle phi-destruction :)");
250 phi_block = get_nodes_block(phi);
251 phi_reg = get_reg(phi);
252 cls = arch_get_irn_reg_class(get_chordal_arch(chordal_env), phi, -1);
254 /* process all arguments of the phi */
255 for (i = 0, max = get_irn_arity(phi); i < max; ++i) {
256 arg = get_irn_n(phi, i);
257 arg_block = get_Block_cfgpred_block(phi_block, i);
258 arg_reg = get_reg(arg);
260 if (arch_irn_is(chordal_env->birg->main_env->arch_env, arg, ignore))
263 assert(arg_reg && "Register must be set while placing perms");
265 DBG((dbg, LEVEL_1, " for %+F(%s) -- %+F(%s)\n", phi, phi_reg->name, arg, arg_reg->name));
267 if (values_interfere(chordal_env->birg, phi, arg)) {
269 Insert a duplicate in arguments block,
270 make it the new phi arg,
272 insert it into schedule,
275 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, arg);
277 /* this is commented out because it will fail in case of unknown float */
279 ir_mode *m_phi = get_irn_mode(phi), *m_dupl = get_irn_mode(dupl);
282 Conv signed <-> unsigned is killed on ia32
283 check for: (both int OR both float) AND equal mode sizes
285 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
286 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
287 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
290 set_irn_n(phi, i, dupl);
291 set_reg(dupl, phi_reg);
292 sched_add_after(sched_skip(sched_last(arg_block), 0, sched_skip_cf_predicator, chordal_env->birg->main_env->arch_env), dupl);
293 pin_irn(dupl, phi_block);
294 be_liveness_introduce(lv, dupl);
295 be_liveness_update(lv, arg);
296 DBG((dbg, LEVEL_1, " they do interfere: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
297 continue; /* with next argument */
300 if (phi_reg == arg_reg) {
301 /* Phi and arg have the same register, so pin and continue */
302 pin_irn(arg, phi_block);
303 DBG((dbg, LEVEL_1, " arg has same reg: pin %+F(%s)\n", arg, get_reg(arg)->name));
307 DBG((dbg, LEVEL_1, " they do not interfere\n"));
308 assert(is_Proj(arg));
310 First check if there is an other phi
312 - having arg at the current pos in its arg-list
313 - having the same color as arg
315 If found, then pin the arg (for that phi)
317 if (! is_pinned(arg)) {
320 DBG((dbg, LEVEL_1, " searching for phi with same arg having args register\n"));
322 for(other_phi = get_irn_link(phi_block); other_phi; other_phi = get_irn_link(other_phi)) {
324 assert(is_Phi(other_phi) &&
325 get_nodes_block(phi) == get_nodes_block(other_phi) &&
326 "link fields are screwed up");
328 if (get_irn_n(other_phi, i) == arg && get_reg(other_phi) == arg_reg) {
329 DBG((dbg, LEVEL_1, " found %+F(%s)\n", other_phi, get_reg(other_phi)->name));
330 pin_irn(arg, phi_block);
336 if (is_pinned(arg)) {
338 Insert a duplicate of the original value in arguments block,
339 make it the new phi arg,
341 insert it into schedule,
344 ir_node *perm = get_Proj_pred(arg);
345 ir_node *dupl = be_new_Copy(cls, chordal_env->irg, arg_block, arg);
348 /* this is commented out because it will fail in case of unknown float */
350 ir_mode *m_phi = get_irn_mode(phi);
351 ir_mode *m_dupl = get_irn_mode(dupl);
354 Conv signed <-> unsigned is killed on ia32
355 check for: (both int OR both float) AND equal mode sizes
357 assert(((mode_is_int(m_phi) && mode_is_int(m_dupl)) ||
358 (mode_is_float(m_phi) && mode_is_float(m_dupl))) &&
359 (get_mode_size_bits(m_phi) == get_mode_size_bits(m_dupl)));
362 set_irn_n(phi, i, dupl);
363 set_reg(dupl, phi_reg);
364 /* skip the Perm's Projs and insert the copies behind. */
365 for(ins = sched_next(perm); is_Proj(ins); ins = sched_next(ins));
366 sched_add_before(ins, dupl);
367 pin_irn(dupl, phi_block);
368 be_liveness_introduce(lv, dupl);
369 be_liveness_update(lv, arg);
370 DBG((dbg, LEVEL_1, " arg is pinned: insert %+F(%s)\n", dupl, get_reg(dupl)->name));
373 No other phi has the same color (else arg would have been pinned),
374 so just set the register and pin
376 set_reg(arg, phi_reg);
377 pin_irn(arg, phi_block);
378 DBG((dbg, LEVEL_1, " arg is not pinned: so pin %+F(%s)\n", arg, get_reg(arg)->name));
384 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);
393 be_liveness_assure_sets(lv);
395 /* create a map for fast lookup of perms: block --> perm */
396 irg_walk_graph(irg, clear_link, collect_phis_walker, chordal_env);
398 DBG((dbg, LEVEL_1, "Placing perms...\n"));
399 insert_perms_env.chordal_env = chordal_env;
400 insert_perms_env.perm_map = perm_map;
401 irg_block_walk_graph(irg, insert_all_perms_walker, NULL, &insert_perms_env);
403 // Matze: really needed here?
404 // Sebastian: Yes. the walker function uses interference.
405 be_liveness_invalidate(lv);
407 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
408 be_dump(irg, "-ssa_destr_perms_placed", dump_ir_block_graph_sched);
410 be_liveness_assure_chk(lv);
412 DBG((dbg, LEVEL_1, "Setting regs and placing dupls...\n"));
413 irg_block_walk_graph(irg, set_regs_or_place_dupls_walker, NULL, chordal_env);
415 /* TODO: unfortunaltely updating doesn't work yet. */
416 be_liveness_invalidate(lv);
418 if (chordal_env->opts->dump_flags & BE_CH_DUMP_SSADESTR)
419 be_dump(irg, "-ssa_destr_regs_set", dump_ir_block_graph_sched);
421 pmap_destroy(perm_map);
424 static void ssa_destruction_check_walker(ir_node *bl, void *data) {
425 be_chordal_env_t *chordal_env = 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);
437 if (arch_irn_is(chordal_env->birg->main_env->arch_env, arg, ignore))
440 arg_reg = get_reg(arg);
442 if (phi_reg != arg_reg) {
443 DBG((dbg, 0, "Error: Registers of %+F and %+F differ: %s %s\n", phi, arg, phi_reg->name, arg_reg->name));
447 if (! is_pinned(arg)) {
448 DBG((dbg, 0, "Warning: Phi argument %+F is not pinned.\n", arg));
455 void be_ssa_destruction_check(be_chordal_env_t *chordal_env) {
456 irg_block_walk_graph(chordal_env->irg, ssa_destruction_check_walker, NULL, chordal_env);