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3d436d2a | 1 | /* Natural loop analysis code for GNU compiler. |
83f676b3 | 2 | Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
3d436d2a ZD |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 2, or (at your option) any later | |
9 | version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING. If not, write to the Free | |
366ccddb KC |
18 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
19 | 02110-1301, USA. */ | |
3d436d2a ZD |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "rtl.h" | |
26 | #include "hard-reg-set.h" | |
7932a3db | 27 | #include "obstack.h" |
3d436d2a ZD |
28 | #include "basic-block.h" |
29 | #include "cfgloop.h" | |
30 | #include "expr.h" | |
31 | #include "output.h" | |
32 | ||
3d436d2a | 33 | /* Checks whether BB is executed exactly once in each LOOP iteration. */ |
f2dca510 | 34 | |
3d436d2a | 35 | bool |
6c878b23 | 36 | just_once_each_iteration_p (const struct loop *loop, basic_block bb) |
3d436d2a ZD |
37 | { |
38 | /* It must be executed at least once each iteration. */ | |
d47cc544 | 39 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb)) |
3d436d2a ZD |
40 | return false; |
41 | ||
42 | /* And just once. */ | |
43 | if (bb->loop_father != loop) | |
44 | return false; | |
45 | ||
46 | /* But this was not enough. We might have some irreducible loop here. */ | |
47 | if (bb->flags & BB_IRREDUCIBLE_LOOP) | |
48 | return false; | |
49 | ||
50 | return true; | |
51 | } | |
52 | ||
cfbe3efe ZD |
53 | /* Structure representing edge of a graph. */ |
54 | ||
55 | struct edge | |
56 | { | |
57 | int src, dest; /* Source and destination. */ | |
58 | struct edge *pred_next, *succ_next; | |
59 | /* Next edge in predecessor and successor lists. */ | |
60 | void *data; /* Data attached to the edge. */ | |
61 | }; | |
62 | ||
63 | /* Structure representing vertex of a graph. */ | |
64 | ||
65 | struct vertex | |
66 | { | |
67 | struct edge *pred, *succ; | |
68 | /* Lists of predecessors and successors. */ | |
69 | int component; /* Number of dfs restarts before reaching the | |
70 | vertex. */ | |
71 | int post; /* Postorder number. */ | |
72 | }; | |
73 | ||
74 | /* Structure representing a graph. */ | |
75 | ||
76 | struct graph | |
77 | { | |
78 | int n_vertices; /* Number of vertices. */ | |
79 | struct vertex *vertices; | |
80 | /* The vertices. */ | |
81 | }; | |
82 | ||
83 | /* Dumps graph G into F. */ | |
84 | ||
85 | extern void dump_graph (FILE *, struct graph *); | |
83f676b3 RS |
86 | |
87 | void | |
88 | dump_graph (FILE *f, struct graph *g) | |
cfbe3efe ZD |
89 | { |
90 | int i; | |
91 | struct edge *e; | |
92 | ||
93 | for (i = 0; i < g->n_vertices; i++) | |
94 | { | |
95 | if (!g->vertices[i].pred | |
96 | && !g->vertices[i].succ) | |
97 | continue; | |
98 | ||
99 | fprintf (f, "%d (%d)\t<-", i, g->vertices[i].component); | |
100 | for (e = g->vertices[i].pred; e; e = e->pred_next) | |
101 | fprintf (f, " %d", e->src); | |
102 | fprintf (f, "\n"); | |
103 | ||
104 | fprintf (f, "\t->"); | |
105 | for (e = g->vertices[i].succ; e; e = e->succ_next) | |
106 | fprintf (f, " %d", e->dest); | |
107 | fprintf (f, "\n"); | |
108 | } | |
109 | } | |
110 | ||
111 | /* Creates a new graph with N_VERTICES vertices. */ | |
112 | ||
113 | static struct graph * | |
114 | new_graph (int n_vertices) | |
115 | { | |
5ed6ace5 | 116 | struct graph *g = XNEW (struct graph); |
cfbe3efe ZD |
117 | |
118 | g->n_vertices = n_vertices; | |
5ed6ace5 | 119 | g->vertices = XCNEWVEC (struct vertex, n_vertices); |
cfbe3efe ZD |
120 | |
121 | return g; | |
122 | } | |
123 | ||
124 | /* Adds an edge from F to T to graph G, with DATA attached. */ | |
125 | ||
126 | static void | |
127 | add_edge (struct graph *g, int f, int t, void *data) | |
128 | { | |
129 | struct edge *e = xmalloc (sizeof (struct edge)); | |
130 | ||
131 | e->src = f; | |
132 | e->dest = t; | |
133 | e->data = data; | |
134 | ||
135 | e->pred_next = g->vertices[t].pred; | |
136 | g->vertices[t].pred = e; | |
137 | ||
138 | e->succ_next = g->vertices[f].succ; | |
139 | g->vertices[f].succ = e; | |
140 | } | |
141 | ||
142 | /* Runs dfs search over vertices of G, from NQ vertices in queue QS. | |
143 | The vertices in postorder are stored into QT. If FORWARD is false, | |
144 | backward dfs is run. */ | |
145 | ||
146 | static void | |
147 | dfs (struct graph *g, int *qs, int nq, int *qt, bool forward) | |
148 | { | |
149 | int i, tick = 0, v, comp = 0, top; | |
150 | struct edge *e; | |
151 | struct edge **stack = xmalloc (sizeof (struct edge *) * g->n_vertices); | |
152 | ||
153 | for (i = 0; i < g->n_vertices; i++) | |
154 | { | |
155 | g->vertices[i].component = -1; | |
156 | g->vertices[i].post = -1; | |
157 | } | |
158 | ||
159 | #define FST_EDGE(V) (forward ? g->vertices[(V)].succ : g->vertices[(V)].pred) | |
160 | #define NEXT_EDGE(E) (forward ? (E)->succ_next : (E)->pred_next) | |
161 | #define EDGE_SRC(E) (forward ? (E)->src : (E)->dest) | |
162 | #define EDGE_DEST(E) (forward ? (E)->dest : (E)->src) | |
163 | ||
164 | for (i = 0; i < nq; i++) | |
165 | { | |
166 | v = qs[i]; | |
167 | if (g->vertices[v].post != -1) | |
168 | continue; | |
169 | ||
170 | g->vertices[v].component = comp++; | |
171 | e = FST_EDGE (v); | |
172 | top = 0; | |
173 | ||
174 | while (1) | |
175 | { | |
176 | while (e && g->vertices[EDGE_DEST (e)].component != -1) | |
177 | e = NEXT_EDGE (e); | |
178 | ||
179 | if (!e) | |
180 | { | |
181 | if (qt) | |
182 | qt[tick] = v; | |
c22cacf3 | 183 | g->vertices[v].post = tick++; |
cfbe3efe ZD |
184 | |
185 | if (!top) | |
186 | break; | |
187 | ||
188 | e = stack[--top]; | |
189 | v = EDGE_SRC (e); | |
190 | e = NEXT_EDGE (e); | |
191 | continue; | |
192 | } | |
193 | ||
194 | stack[top++] = e; | |
195 | v = EDGE_DEST (e); | |
196 | e = FST_EDGE (v); | |
197 | g->vertices[v].component = comp - 1; | |
198 | } | |
199 | } | |
200 | ||
201 | free (stack); | |
202 | } | |
203 | ||
204 | /* Marks the edge E in graph G irreducible if it connects two vertices in the | |
205 | same scc. */ | |
206 | ||
207 | static void | |
208 | check_irred (struct graph *g, struct edge *e) | |
209 | { | |
210 | edge real = e->data; | |
211 | ||
212 | /* All edges should lead from a component with higher number to the | |
213 | one with lower one. */ | |
341c100f | 214 | gcc_assert (g->vertices[e->src].component >= g->vertices[e->dest].component); |
cfbe3efe ZD |
215 | |
216 | if (g->vertices[e->src].component != g->vertices[e->dest].component) | |
217 | return; | |
218 | ||
219 | real->flags |= EDGE_IRREDUCIBLE_LOOP; | |
220 | if (flow_bb_inside_loop_p (real->src->loop_father, real->dest)) | |
221 | real->src->flags |= BB_IRREDUCIBLE_LOOP; | |
222 | } | |
223 | ||
224 | /* Runs CALLBACK for all edges in G. */ | |
225 | ||
226 | static void | |
227 | for_each_edge (struct graph *g, | |
228 | void (callback) (struct graph *, struct edge *)) | |
229 | { | |
230 | struct edge *e; | |
231 | int i; | |
232 | ||
233 | for (i = 0; i < g->n_vertices; i++) | |
234 | for (e = g->vertices[i].succ; e; e = e->succ_next) | |
235 | callback (g, e); | |
236 | } | |
237 | ||
238 | /* Releases the memory occupied by G. */ | |
239 | ||
240 | static void | |
241 | free_graph (struct graph *g) | |
242 | { | |
243 | struct edge *e, *n; | |
244 | int i; | |
245 | ||
246 | for (i = 0; i < g->n_vertices; i++) | |
247 | for (e = g->vertices[i].succ; e; e = n) | |
248 | { | |
249 | n = e->succ_next; | |
250 | free (e); | |
251 | } | |
252 | free (g->vertices); | |
253 | free (g); | |
254 | } | |
255 | ||
35b07080 ZD |
256 | /* Marks blocks and edges that are part of non-recognized loops; i.e. we |
257 | throw away all latch edges and mark blocks inside any remaining cycle. | |
258 | Everything is a bit complicated due to fact we do not want to do this | |
259 | for parts of cycles that only "pass" through some loop -- i.e. for | |
260 | each cycle, we want to mark blocks that belong directly to innermost | |
cfbe3efe | 261 | loop containing the whole cycle. |
c22cacf3 | 262 | |
cfbe3efe ZD |
263 | LOOPS is the loop tree. */ |
264 | ||
265 | #define LOOP_REPR(LOOP) ((LOOP)->num + last_basic_block) | |
266 | #define BB_REPR(BB) ((BB)->index + 1) | |
267 | ||
3d436d2a | 268 | void |
d73be268 | 269 | mark_irreducible_loops (void) |
3d436d2a | 270 | { |
3d436d2a | 271 | basic_block act; |
cfbe3efe | 272 | edge e; |
628f6a4e | 273 | edge_iterator ei; |
cfbe3efe ZD |
274 | int i, src, dest; |
275 | struct graph *g; | |
42fd6772 | 276 | int num = current_loops ? number_of_loops () : 1; |
598ec7bd ZD |
277 | int *queue1 = XNEWVEC (int, last_basic_block + num); |
278 | int *queue2 = XNEWVEC (int, last_basic_block + num); | |
cfbe3efe | 279 | int nq, depth; |
42fd6772 ZD |
280 | struct loop *cloop, *loop; |
281 | loop_iterator li; | |
3d436d2a | 282 | |
35b07080 ZD |
283 | /* Reset the flags. */ |
284 | FOR_BB_BETWEEN (act, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) | |
285 | { | |
286 | act->flags &= ~BB_IRREDUCIBLE_LOOP; | |
628f6a4e | 287 | FOR_EACH_EDGE (e, ei, act->succs) |
35b07080 ZD |
288 | e->flags &= ~EDGE_IRREDUCIBLE_LOOP; |
289 | } | |
290 | ||
3d436d2a | 291 | /* Create the edge lists. */ |
598ec7bd | 292 | g = new_graph (last_basic_block + num); |
cfbe3efe | 293 | |
3d436d2a | 294 | FOR_BB_BETWEEN (act, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) |
628f6a4e | 295 | FOR_EACH_EDGE (e, ei, act->succs) |
3d436d2a | 296 | { |
c22cacf3 MS |
297 | /* Ignore edges to exit. */ |
298 | if (e->dest == EXIT_BLOCK_PTR) | |
3d436d2a | 299 | continue; |
cfbe3efe | 300 | |
598ec7bd ZD |
301 | src = BB_REPR (act); |
302 | dest = BB_REPR (e->dest); | |
cfbe3efe | 303 | |
d73be268 | 304 | if (current_loops) |
598ec7bd ZD |
305 | { |
306 | /* Ignore latch edges. */ | |
307 | if (e->dest->loop_father->header == e->dest | |
308 | && e->dest->loop_father->latch == act) | |
309 | continue; | |
cfbe3efe | 310 | |
598ec7bd ZD |
311 | /* Edges inside a single loop should be left where they are. Edges |
312 | to subloop headers should lead to representative of the subloop, | |
313 | but from the same place. | |
3d436d2a | 314 | |
598ec7bd ZD |
315 | Edges exiting loops should lead from representative |
316 | of the son of nearest common ancestor of the loops in that | |
317 | act lays. */ | |
3d436d2a | 318 | |
598ec7bd ZD |
319 | if (e->dest->loop_father->header == e->dest) |
320 | dest = LOOP_REPR (e->dest->loop_father); | |
cfbe3efe | 321 | |
598ec7bd ZD |
322 | if (!flow_bb_inside_loop_p (act->loop_father, e->dest)) |
323 | { | |
324 | depth = find_common_loop (act->loop_father, | |
325 | e->dest->loop_father)->depth + 1; | |
326 | if (depth == act->loop_father->depth) | |
327 | cloop = act->loop_father; | |
328 | else | |
329 | cloop = act->loop_father->pred[depth]; | |
330 | ||
331 | src = LOOP_REPR (cloop); | |
332 | } | |
3d436d2a | 333 | } |
cfbe3efe ZD |
334 | |
335 | add_edge (g, src, dest, e); | |
3d436d2a ZD |
336 | } |
337 | ||
cfbe3efe ZD |
338 | /* Find the strongly connected components. Use the algorithm of Tarjan -- |
339 | first determine the postorder dfs numbering in reversed graph, then | |
340 | run the dfs on the original graph in the order given by decreasing | |
341 | numbers assigned by the previous pass. */ | |
342 | nq = 0; | |
343 | FOR_BB_BETWEEN (act, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb) | |
3d436d2a | 344 | { |
cfbe3efe | 345 | queue1[nq++] = BB_REPR (act); |
3d436d2a | 346 | } |
42fd6772 ZD |
347 | |
348 | if (current_loops) | |
349 | { | |
350 | FOR_EACH_LOOP (li, loop, 0) | |
351 | { | |
352 | queue1[nq++] = LOOP_REPR (loop); | |
353 | } | |
354 | } | |
cfbe3efe ZD |
355 | dfs (g, queue1, nq, queue2, false); |
356 | for (i = 0; i < nq; i++) | |
357 | queue1[i] = queue2[nq - i - 1]; | |
358 | dfs (g, queue1, nq, NULL, true); | |
3d436d2a | 359 | |
cfbe3efe ZD |
360 | /* Mark the irreducible loops. */ |
361 | for_each_edge (g, check_irred); | |
3d436d2a | 362 | |
cfbe3efe ZD |
363 | free_graph (g); |
364 | free (queue1); | |
365 | free (queue2); | |
3d436d2a | 366 | |
d73be268 ZD |
367 | if (current_loops) |
368 | current_loops->state |= LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS; | |
3d436d2a ZD |
369 | } |
370 | ||
371 | /* Counts number of insns inside LOOP. */ | |
372 | int | |
d329e058 | 373 | num_loop_insns (struct loop *loop) |
3d436d2a ZD |
374 | { |
375 | basic_block *bbs, bb; | |
376 | unsigned i, ninsns = 0; | |
377 | rtx insn; | |
378 | ||
379 | bbs = get_loop_body (loop); | |
380 | for (i = 0; i < loop->num_nodes; i++) | |
381 | { | |
382 | bb = bbs[i]; | |
383 | ninsns++; | |
a813c111 | 384 | for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn)) |
91f4cfe3 ZD |
385 | if (INSN_P (insn)) |
386 | ninsns++; | |
3d436d2a ZD |
387 | } |
388 | free(bbs); | |
d329e058 | 389 | |
3d436d2a ZD |
390 | return ninsns; |
391 | } | |
392 | ||
393 | /* Counts number of insns executed on average per iteration LOOP. */ | |
394 | int | |
d329e058 | 395 | average_num_loop_insns (struct loop *loop) |
3d436d2a ZD |
396 | { |
397 | basic_block *bbs, bb; | |
398 | unsigned i, binsns, ninsns, ratio; | |
399 | rtx insn; | |
400 | ||
401 | ninsns = 0; | |
402 | bbs = get_loop_body (loop); | |
403 | for (i = 0; i < loop->num_nodes; i++) | |
404 | { | |
405 | bb = bbs[i]; | |
406 | ||
407 | binsns = 1; | |
a813c111 | 408 | for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn)) |
91f4cfe3 ZD |
409 | if (INSN_P (insn)) |
410 | binsns++; | |
3d436d2a ZD |
411 | |
412 | ratio = loop->header->frequency == 0 | |
413 | ? BB_FREQ_MAX | |
414 | : (bb->frequency * BB_FREQ_MAX) / loop->header->frequency; | |
415 | ninsns += binsns * ratio; | |
416 | } | |
417 | free(bbs); | |
d329e058 | 418 | |
3d436d2a ZD |
419 | ninsns /= BB_FREQ_MAX; |
420 | if (!ninsns) | |
421 | ninsns = 1; /* To avoid division by zero. */ | |
422 | ||
423 | return ninsns; | |
424 | } | |
425 | ||
ac84e05e ZD |
426 | /* Returns expected number of iterations of LOOP, according to |
427 | measured or guessed profile. No bounding is done on the | |
428 | value. */ | |
429 | ||
430 | gcov_type | |
431 | expected_loop_iterations_unbounded (const struct loop *loop) | |
3d436d2a ZD |
432 | { |
433 | edge e; | |
628f6a4e | 434 | edge_iterator ei; |
3d436d2a | 435 | |
997de8ed | 436 | if (loop->latch->count || loop->header->count) |
3d436d2a ZD |
437 | { |
438 | gcov_type count_in, count_latch, expected; | |
439 | ||
440 | count_in = 0; | |
441 | count_latch = 0; | |
442 | ||
628f6a4e | 443 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
3d436d2a ZD |
444 | if (e->src == loop->latch) |
445 | count_latch = e->count; | |
446 | else | |
447 | count_in += e->count; | |
448 | ||
449 | if (count_in == 0) | |
c22cacf3 | 450 | expected = count_latch * 2; |
bade3a00 | 451 | else |
c22cacf3 | 452 | expected = (count_latch + count_in - 1) / count_in; |
3d436d2a | 453 | |
ac84e05e | 454 | return expected; |
3d436d2a ZD |
455 | } |
456 | else | |
457 | { | |
458 | int freq_in, freq_latch; | |
459 | ||
460 | freq_in = 0; | |
461 | freq_latch = 0; | |
462 | ||
628f6a4e | 463 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
3d436d2a ZD |
464 | if (e->src == loop->latch) |
465 | freq_latch = EDGE_FREQUENCY (e); | |
466 | else | |
467 | freq_in += EDGE_FREQUENCY (e); | |
468 | ||
469 | if (freq_in == 0) | |
bade3a00 | 470 | return freq_latch * 2; |
3d436d2a ZD |
471 | |
472 | return (freq_latch + freq_in - 1) / freq_in; | |
473 | } | |
474 | } | |
689ba89d | 475 | |
ac84e05e ZD |
476 | /* Returns expected number of LOOP iterations. The returned value is bounded |
477 | by REG_BR_PROB_BASE. */ | |
478 | ||
479 | unsigned | |
480 | expected_loop_iterations (const struct loop *loop) | |
481 | { | |
482 | gcov_type expected = expected_loop_iterations_unbounded (loop); | |
483 | return (expected > REG_BR_PROB_BASE ? REG_BR_PROB_BASE : expected); | |
484 | } | |
485 | ||
689ba89d ZD |
486 | /* Returns the maximum level of nesting of subloops of LOOP. */ |
487 | ||
488 | unsigned | |
489 | get_loop_level (const struct loop *loop) | |
490 | { | |
491 | const struct loop *ploop; | |
492 | unsigned mx = 0, l; | |
493 | ||
494 | for (ploop = loop->inner; ploop; ploop = ploop->next) | |
495 | { | |
496 | l = get_loop_level (ploop); | |
497 | if (l >= mx) | |
498 | mx = l + 1; | |
499 | } | |
500 | return mx; | |
501 | } | |
5e962776 ZD |
502 | |
503 | /* Returns estimate on cost of computing SEQ. */ | |
504 | ||
505 | static unsigned | |
506 | seq_cost (rtx seq) | |
507 | { | |
508 | unsigned cost = 0; | |
509 | rtx set; | |
510 | ||
511 | for (; seq; seq = NEXT_INSN (seq)) | |
512 | { | |
513 | set = single_set (seq); | |
514 | if (set) | |
515 | cost += rtx_cost (set, SET); | |
516 | else | |
517 | cost++; | |
518 | } | |
519 | ||
520 | return cost; | |
521 | } | |
522 | ||
523 | /* The properties of the target. */ | |
524 | ||
8b11a64c ZD |
525 | unsigned target_avail_regs; /* Number of available registers. */ |
526 | unsigned target_res_regs; /* Number of reserved registers. */ | |
527 | unsigned target_small_cost; /* The cost for register when there is a free one. */ | |
528 | unsigned target_pres_cost; /* The cost for register when there are not too many | |
5e962776 | 529 | free ones. */ |
8b11a64c | 530 | unsigned target_spill_cost; /* The cost for register when we need to spill. */ |
5e962776 ZD |
531 | |
532 | /* Initialize the constants for computing set costs. */ | |
533 | ||
534 | void | |
535 | init_set_costs (void) | |
536 | { | |
537 | rtx seq; | |
538 | rtx reg1 = gen_raw_REG (SImode, FIRST_PSEUDO_REGISTER); | |
539 | rtx reg2 = gen_raw_REG (SImode, FIRST_PSEUDO_REGISTER + 1); | |
540 | rtx addr = gen_raw_REG (Pmode, FIRST_PSEUDO_REGISTER + 2); | |
541 | rtx mem = validize_mem (gen_rtx_MEM (SImode, addr)); | |
542 | unsigned i; | |
543 | ||
544 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
545 | if (TEST_HARD_REG_BIT (reg_class_contents[GENERAL_REGS], i) | |
546 | && !fixed_regs[i]) | |
8b11a64c | 547 | target_avail_regs++; |
5e962776 | 548 | |
8b11a64c | 549 | target_res_regs = 3; |
5e962776 ZD |
550 | |
551 | /* These are really just heuristic values. */ | |
c22cacf3 | 552 | |
5e962776 ZD |
553 | start_sequence (); |
554 | emit_move_insn (reg1, reg2); | |
555 | seq = get_insns (); | |
556 | end_sequence (); | |
8b11a64c ZD |
557 | target_small_cost = seq_cost (seq); |
558 | target_pres_cost = 2 * target_small_cost; | |
5e962776 ZD |
559 | |
560 | start_sequence (); | |
561 | emit_move_insn (mem, reg1); | |
562 | emit_move_insn (reg2, mem); | |
563 | seq = get_insns (); | |
564 | end_sequence (); | |
8b11a64c | 565 | target_spill_cost = seq_cost (seq); |
5e962776 ZD |
566 | } |
567 | ||
568 | /* Calculates cost for having SIZE new loop global variables. REGS_USED is the | |
569 | number of global registers used in loop. N_USES is the number of relevant | |
570 | variable uses. */ | |
571 | ||
572 | unsigned | |
573 | global_cost_for_size (unsigned size, unsigned regs_used, unsigned n_uses) | |
574 | { | |
575 | unsigned regs_needed = regs_used + size; | |
576 | unsigned cost = 0; | |
577 | ||
8b11a64c ZD |
578 | if (regs_needed + target_res_regs <= target_avail_regs) |
579 | cost += target_small_cost * size; | |
580 | else if (regs_needed <= target_avail_regs) | |
581 | cost += target_pres_cost * size; | |
5e962776 ZD |
582 | else |
583 | { | |
8b11a64c ZD |
584 | cost += target_pres_cost * size; |
585 | cost += target_spill_cost * n_uses * (regs_needed - target_avail_regs) / regs_needed; | |
5e962776 ZD |
586 | } |
587 | ||
588 | return cost; | |
589 | } | |
590 | ||
d73be268 | 591 | /* Sets EDGE_LOOP_EXIT flag for all loop exits. */ |
70388d94 ZD |
592 | |
593 | void | |
d73be268 | 594 | mark_loop_exit_edges (void) |
70388d94 ZD |
595 | { |
596 | basic_block bb; | |
597 | edge e; | |
c22cacf3 | 598 | |
d73be268 | 599 | if (!current_loops) |
70388d94 ZD |
600 | return; |
601 | ||
602 | FOR_EACH_BB (bb) | |
603 | { | |
604 | edge_iterator ei; | |
605 | ||
70388d94 ZD |
606 | FOR_EACH_EDGE (e, ei, bb->succs) |
607 | { | |
2ff3e325 ZD |
608 | if (bb->loop_father->outer |
609 | && loop_exit_edge_p (bb->loop_father, e)) | |
70388d94 ZD |
610 | e->flags |= EDGE_LOOP_EXIT; |
611 | else | |
612 | e->flags &= ~EDGE_LOOP_EXIT; | |
613 | } | |
614 | } | |
615 | } | |
616 |