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
21 * @file ir/opt/ifconv.c
22 * @brief If conversion
23 * @author Christoph Mallon
32 #include "iroptimize.h"
49 DEBUG_ONLY(static firm_dbg_module_t *dbg);
51 /** allow every Psi to be created. */
52 static int default_allow_ifconv(ir_node *sel, ir_node* phi_list, int i, int j)
64 static const ir_settings_if_conv_t default_info = {
65 0, /* doesn't matter for Psi */
70 * Additional block info.
72 typedef struct block_info {
73 ir_node *phi; /**< head of the Phi list */
74 int has_pinned; /**< set if the block contains instructions that cannot be moved */
78 static INLINE block_info* get_block_blockinfo(const ir_node* block)
80 return get_irn_link(block);
85 * Returns non-zero if a Block can be emptied.
87 static int can_empty_block(ir_node *block)
89 return !get_block_blockinfo(block)->has_pinned;
93 static ir_node* walk_to_projx(ir_node* start, const ir_node* dependency)
98 /* No need to find the conditional block if this block cannot be emptied and
99 * therefore not moved */
100 if (!can_empty_block(start)) return NULL;
102 arity = get_irn_arity(start);
103 for (i = 0; i < arity; ++i) {
104 ir_node* pred = get_irn_n(start, i);
105 ir_node* pred_block = get_nodes_block(pred);
107 if (pred_block == dependency) {
109 assert(get_irn_mode(pred) == mode_X);
116 assert(get_irn_mode(pred) == mode_X);
120 if (is_cdep_on(pred_block, dependency)) {
121 return walk_to_projx(pred_block, dependency);
129 * Copies the DAG starting at node to the ith predecessor block of src_block
130 * -if the node isn't in the src_block, this is a nop and the node is returned
131 * -if the node is a phi in the src_block, the ith predecessor of the phi is
133 * otherwise returns the copy of the passed node
135 static ir_node* copy_to(ir_node* node, ir_node* src_block, int i)
142 if (get_nodes_block(node) != src_block) return node;
143 if (get_irn_op(node) == op_Phi) return get_irn_n(node, i);
145 copy = exact_copy(node);
146 dst_block = get_nodes_block(get_irn_n(src_block, i));
147 set_nodes_block(copy, dst_block);
149 DB((dbg, LEVEL_1, "Copying node %+F to block %+F, copy is %+F\n",
150 node, dst_block, copy));
152 arity = get_irn_arity(node);
153 for (j = 0; j < arity; ++j) {
154 set_irn_n(copy, j, copy_to(get_irn_n(node, j), src_block, i));
155 DB((dbg, LEVEL_2, "-- pred %d is %+F\n", j, get_irn_n(copy, j)));
162 * Remove predecessors i and j from node and add predecessor new_pred
164 static void rewire(ir_node* node, int i, int j, ir_node* new_pred)
166 int arity = get_irn_arity(node);
171 NEW_ARR_A(ir_node *, ins, arity - 1);
174 for (k = 0; k < i; ++k) ins[l++] = get_irn_n(node, k);
175 for (++k; k < j; ++k) ins[l++] = get_irn_n(node, k);
176 for (++k; k < arity; ++k) ins[l++] = get_irn_n(node, k);
178 assert(l == arity - 1);
179 set_irn_in(node, l, ins);
184 * Remove the jth predecessors from the ith predecessor of block and add it to block
186 static void split_block(ir_node* block, int i, int j)
188 ir_node* pred_block = get_nodes_block(get_irn_n(block, i));
189 int arity = get_irn_arity(block);
196 DB((dbg, LEVEL_1, "Splitting predecessor %d of predecessor %d of %+F\n", j, i, block));
198 NEW_ARR_A(ir_node*, ins, arity + 1);
200 for (phi = get_block_blockinfo(block)->phi; phi != NULL; phi = get_irn_link(phi)) {
201 ir_node* copy = copy_to(get_irn_n(phi, i), pred_block, j);
203 for (k = 0; k < i; ++k) ins[k] = get_irn_n(phi, k);
205 for (; k < arity; ++k) ins[k] = get_irn_n(phi, k);
206 ins[k] = get_irn_n(phi, i);
208 set_irn_in(phi, arity + 1, ins);
211 for (k = 0; k < i; ++k) ins[k] = get_irn_n(block, k);
212 ins[k++] = get_irn_n(pred_block, j);
213 for (; k < arity; ++k) ins[k] = get_irn_n(block, k);
214 ins[k] = get_irn_n(block, i);
216 set_irn_in(block, arity + 1, ins);
218 new_pred_arity = get_irn_arity(pred_block) - 1;
219 NEW_ARR_A(ir_node*, pred_ins, new_pred_arity);
221 for (phi = get_block_blockinfo(pred_block)->phi; phi != NULL; phi = get_irn_link(phi)) {
222 for (k = 0; k < j; ++k) pred_ins[k] = get_irn_n(phi, k);
223 for (; k < new_pred_arity; ++k) pred_ins[k] = get_irn_n(phi, k + 1);
224 assert(k == new_pred_arity);
225 if (new_pred_arity > 1) {
226 set_irn_in(phi, new_pred_arity, pred_ins);
228 exchange(phi, pred_ins[0]);
232 for (k = 0; k < j; ++k) pred_ins[k] = get_irn_n(pred_block, k);
233 for (; k < new_pred_arity; ++k) pred_ins[k] = get_irn_n(pred_block, k + 1);
234 assert(k == new_pred_arity);
235 if (new_pred_arity > 1) {
236 set_irn_in(pred_block, new_pred_arity, pred_ins);
238 exchange(pred_block, get_nodes_block(pred_ins[0]));
243 static void prepare_path(ir_node* block, int i, const ir_node* dependency)
245 ir_node* pred = get_nodes_block(get_irn_n(block, i));
249 DB((dbg, LEVEL_1, "Preparing predecessor %d of %+F\n", i, block));
251 pred_arity = get_irn_arity(pred);
252 for (j = 0; j < pred_arity; ++j) {
253 ir_node* pred_pred = get_nodes_block(get_irn_n(pred, j));
255 if (is_cdep_on(pred_pred, dependency)) {
256 prepare_path(pred, j, dependency);
257 split_block(block, i, j);
264 static void if_conv_walker(ir_node* block, void* env)
266 ir_settings_if_conv_t* opt_info = env;
270 /* Bail out, if there are no Phis at all */
271 if (get_block_blockinfo(block)->phi == NULL) return;
274 arity = get_irn_arity(block);
275 for (i = 0; i < arity; ++i) {
279 pred0 = get_nodes_block(get_irn_n(block, i));
280 for (cdep = find_cdep(pred0); cdep != NULL; cdep = cdep->next) {
281 const ir_node* dependency = cdep->node;
282 ir_node* projx0 = walk_to_projx(pred0, dependency);
286 if (projx0 == NULL) continue;
288 cond = get_Proj_pred(projx0);
289 if (get_irn_op(cond) != op_Cond) continue;
291 /* We only handle boolean decisions, no switches */
292 if (get_irn_mode(get_Cond_selector(cond)) != mode_b) continue;
294 for (j = i + 1; j < arity; ++j) {
302 pred1 = get_nodes_block(get_irn_n(block, j));
304 if (!is_cdep_on(pred1, dependency)) continue;
306 projx1 = walk_to_projx(pred1, dependency);
308 if (projx1 == NULL) continue;
310 phi = get_block_blockinfo(block)->phi;
311 if (!opt_info->allow_ifconv(get_Cond_selector(cond), phi, i, j)) continue;
313 DB((dbg, LEVEL_1, "Found Cond %+F with proj %+F and %+F\n",
317 prepare_path(block, i, dependency);
318 prepare_path(block, j, dependency);
319 arity = get_irn_arity(block);
321 conds[0] = get_Cond_selector(cond);
323 psi_block = get_nodes_block(cond);
324 cond_dbg = get_irn_dbg_info(cond);
326 ir_node* val_i = get_irn_n(phi, i);
327 ir_node* val_j = get_irn_n(phi, j);
331 if (val_i == val_j) {
333 DB((dbg, LEVEL_2, "Generating no psi, because both values are equal\n"));
337 /* Something is very fishy if two predecessors of a PhiM point into
338 * one block, but not at the same memory node
340 assert(get_irn_mode(phi) != mode_M);
341 if (get_Proj_proj(projx0) == pn_Cond_true) {
349 psi = new_rd_Psi(cond_dbg, current_ir_graph, psi_block, 1, conds, vals, get_irn_mode(phi));
350 DB((dbg, LEVEL_2, "Generating %+F for %+F\n", psi, phi));
353 next_phi = get_irn_link(phi);
358 rewire(phi, i, j, psi);
362 } while (phi != NULL);
364 exchange(get_nodes_block(get_irn_n(block, i)), psi_block);
365 exchange(get_nodes_block(get_irn_n(block, j)), psi_block);
369 DB((dbg, LEVEL_1, "Welding block %+F and %+F\n", block, psi_block));
370 /* copy the block-info from the Psi-block to the block before merging */
371 get_block_blockinfo(psi_block)->has_pinned |= get_block_blockinfo(block)->has_pinned;
372 set_irn_link(block, get_irn_link(psi_block));
374 set_irn_in(block, get_irn_arity(psi_block), get_irn_in(psi_block) + 1);
375 exchange_cdep(psi_block, block);
376 exchange(psi_block, block);
378 DB((dbg, LEVEL_1, "Welding block %+F to %+F\n", block, psi_block));
379 get_block_blockinfo(psi_block)->has_pinned |= get_block_blockinfo(block)->has_pinned;
380 exchange(block, psi_block);
384 rewire(block, i, j, new_r_Jmp(current_ir_graph, psi_block));
393 * Block walker: add additional data
395 static void init_block_link(ir_node *block, void *env)
397 struct obstack *obst = env;
398 block_info *bi = obstack_alloc(obst, sizeof(*bi));
402 set_irn_link(block, bi);
407 * Daisy-chain all phis in a block
408 * If a non-movable node is encountered set the has_pinned flag
410 static void collect_phis(ir_node *node, void *env)
415 ir_node *block = get_nodes_block(node);
416 block_info *bi = get_block_blockinfo(block);
418 set_irn_link(node, bi->phi);
421 if (is_no_Block(node) && get_irn_pinned(node) == op_pin_state_pinned) {
423 * Ignore control flow nodes, these will be removed.
424 * This ignores Raise. That is surely bad. FIXME.
426 if (!is_cfop(node)) {
427 ir_node *block = get_nodes_block(node);
428 block_info *bi = get_block_blockinfo(block);
430 DB((dbg, LEVEL_2, "Node %+F in block %+F is unmovable\n", node, block));
437 static void optimise_psis_0(ir_node* psi, void* env)
444 if (!is_Psi(psi)) return;
446 t = get_Psi_val(psi, 0);
447 f = get_Psi_default(psi);
449 DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", psi, t, f));
452 DB((dbg, LEVEL_3, "Replace Psi with unknown operand by %+F\n", f));
457 DB((dbg, LEVEL_3, "Replace Psi with unknown operand by %+F\n", t));
463 ir_graph* irg = current_ir_graph;
464 ir_node* block = get_nodes_block(psi);
465 ir_mode* mode = get_irn_mode(psi);
466 ir_node* c0 = get_Psi_cond(psi, 0);
467 ir_node* c1 = get_Psi_cond(t, 0);
468 ir_node* t1 = get_Psi_val(t, 0);
469 ir_node* f1 = get_Psi_default(t);
471 /* Psi(c0, Psi(c1, x, y), y) -> typical if (c0 && c1) x else y */
472 ir_node* and_ = new_r_And(irg, block, c0, c1, mode_b);
473 ir_node* vals[2] = { t1, f1 };
474 ir_node* new_psi = new_r_Psi(irg, block, 1, &and_, vals, mode);
475 exchange(psi, new_psi);
476 } else if (f == t1) {
477 /* Psi(c0, Psi(c1, x, y), x) */
478 ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
479 ir_node* and_ = new_r_And(irg, block, c0, not_c1, mode_b);
480 ir_node* vals[2] = { f1, t1 };
481 ir_node* new_psi = new_r_Psi(irg, block, 1, &and_, vals, mode);
482 exchange(psi, new_psi);
484 } else if (is_Psi(f)) {
485 ir_graph* irg = current_ir_graph;
486 ir_node* block = get_nodes_block(psi);
487 ir_mode* mode = get_irn_mode(psi);
488 ir_node* c0 = get_Psi_cond(psi, 0);
489 ir_node* c1 = get_Psi_cond(f, 0);
490 ir_node* t1 = get_Psi_val(f, 0);
491 ir_node* f1 = get_Psi_default(f);
493 /* Psi(c0, x, Psi(c1, x, y)) -> typical if (c0 || c1) x else y */
494 ir_node* or_ = new_r_Or(irg, block, c0, c1, mode_b);
495 ir_node* vals[2] = { t1, f1 };
496 ir_node* new_psi = new_r_Psi(irg, block, 1, &or_, vals, mode);
497 exchange(psi, new_psi);
498 } else if (t == f1) {
499 /* Psi(c0, x, Psi(c1, y, x)) */
500 ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
501 ir_node* or_ = new_r_Or(irg, block, c0, not_c1, mode_b);
502 ir_node* vals[2] = { f1, t1 };
503 ir_node* new_psi = new_r_Psi(irg, block, 1, &or_, vals, mode);
504 exchange(psi, new_psi);
510 static void optimise_psis_1(ir_node* psi, void* env)
518 if (!is_Psi(psi)) return;
520 t = get_Psi_val(psi, 0);
521 f = get_Psi_default(psi);
523 DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", psi, t, f));
525 mode = get_irn_mode(psi);
527 if (is_Const(t) && is_Const(f) && (mode_is_int(mode))) {
528 ir_node* block = get_nodes_block(psi);
529 ir_node* c = get_Psi_cond(psi, 0);
530 tarval* tv_t = get_Const_tarval(t);
531 tarval* tv_f = get_Const_tarval(f);
532 if (tarval_is_one(tv_t) && tarval_is_null(tv_f)) {
533 ir_node* conv = new_r_Conv(current_ir_graph, block, c, mode);
535 } else if (tarval_is_null(tv_t) && tarval_is_one(tv_f)) {
536 ir_node* not_ = new_r_Not(current_ir_graph, block, c, mode_b);
537 ir_node* conv = new_r_Conv(current_ir_graph, block, not_, mode);
544 void opt_if_conv(ir_graph *irg, const ir_settings_if_conv_t *params)
547 ir_settings_if_conv_t p;
549 /* get the parameters */
550 p = (params != NULL ? *params : default_info);
552 FIRM_DBG_REGISTER(dbg, "firm.opt.ifconv");
554 DB((dbg, LEVEL_1, "Running if-conversion on %+F\n", irg));
556 normalize_one_return(irg);
557 remove_critical_cf_edges(irg);
563 irg_block_walk_graph(irg, init_block_link, NULL, &obst);
564 irg_walk_graph(irg, collect_phis, NULL, NULL);
565 irg_block_walk_graph(irg, NULL, if_conv_walker, &p);
567 local_optimize_graph(irg);
569 irg_walk_graph(irg, NULL, optimise_psis_0, NULL);
571 irg_walk_graph(irg, NULL, optimise_psis_1, NULL);
574 obstack_free(&obst, NULL);