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1 | /* DDG - Data Dependence Graph implementation. |
2 | Copyright (C) 2004 | |
3 | Free Software Foundation, Inc. | |
4 | Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.com> | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 2, or (at your option) any later | |
11 | version. | |
12 | ||
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GCC; see the file COPYING. If not, write to the Free | |
20 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
21 | 02111-1307, USA. */ | |
22 | ||
23 | ||
24 | #include "config.h" | |
25 | #include "system.h" | |
26 | #include "coretypes.h" | |
27 | #include "tm.h" | |
28 | #include "toplev.h" | |
29 | #include "rtl.h" | |
30 | #include "tm_p.h" | |
31 | #include "hard-reg-set.h" | |
32 | #include "basic-block.h" | |
33 | #include "regs.h" | |
34 | #include "function.h" | |
35 | #include "flags.h" | |
36 | #include "insn-config.h" | |
37 | #include "insn-attr.h" | |
38 | #include "except.h" | |
39 | #include "recog.h" | |
40 | #include "sched-int.h" | |
41 | #include "target.h" | |
42 | #include "cfglayout.h" | |
43 | #include "cfgloop.h" | |
44 | #include "sbitmap.h" | |
45 | #include "expr.h" | |
46 | #include "bitmap.h" | |
47 | #include "df.h" | |
48 | #include "ddg.h" | |
49 | ||
50 | /* A flag indicating that a ddg edge belongs to an SCC or not. */ | |
51 | enum edge_flag {NOT_IN_SCC = 0, IN_SCC}; | |
52 | ||
53 | /* Forward declarations. */ | |
54 | static void add_backarc_to_ddg (ddg_ptr, ddg_edge_ptr); | |
55 | static void add_backarc_to_scc (ddg_scc_ptr, ddg_edge_ptr); | |
56 | static void add_scc_to_ddg (ddg_all_sccs_ptr, ddg_scc_ptr); | |
57 | static void create_ddg_dependence (ddg_ptr, ddg_node_ptr, ddg_node_ptr, rtx); | |
58 | static void create_ddg_dep_no_link (ddg_ptr, ddg_node_ptr, ddg_node_ptr, | |
59 | dep_type, dep_data_type, int); | |
60 | static ddg_edge_ptr create_ddg_edge (ddg_node_ptr, ddg_node_ptr, dep_type, | |
61 | dep_data_type, int, int); | |
62 | static void add_edge_to_ddg (ddg_ptr g, ddg_edge_ptr); | |
63 | \f | |
64 | /* Auxiliary variable for mem_read_insn_p/mem_write_insn_p. */ | |
65 | static bool mem_ref_p; | |
66 | ||
67 | /* Auxiliary function for mem_read_insn_p. */ | |
68 | static int | |
69 | mark_mem_use (rtx *x, void *data ATTRIBUTE_UNUSED) | |
70 | { | |
71 | if (GET_CODE (*x) == MEM) | |
72 | mem_ref_p = true; | |
73 | return 0; | |
74 | } | |
75 | ||
76 | /* Auxiliary function for mem_read_insn_p. */ | |
77 | static void | |
78 | mark_mem_use_1 (rtx *x, void *data) | |
79 | { | |
80 | for_each_rtx (x, mark_mem_use, data); | |
81 | } | |
82 | ||
1ea7e6ad | 83 | /* Returns nonzero if INSN reads from memory. */ |
d397e8c6 MH |
84 | static bool |
85 | mem_read_insn_p (rtx insn) | |
86 | { | |
87 | mem_ref_p = false; | |
88 | note_uses (&PATTERN (insn), mark_mem_use_1, NULL); | |
89 | return mem_ref_p; | |
90 | } | |
91 | ||
92 | static void | |
93 | mark_mem_store (rtx loc, rtx setter ATTRIBUTE_UNUSED, void *data ATTRIBUTE_UNUSED) | |
94 | { | |
95 | if (GET_CODE (loc) == MEM) | |
96 | mem_ref_p = true; | |
97 | } | |
98 | ||
1ea7e6ad | 99 | /* Returns nonzero if INSN writes to memory. */ |
d397e8c6 MH |
100 | static bool |
101 | mem_write_insn_p (rtx insn) | |
102 | { | |
103 | mem_ref_p = false; | |
104 | note_stores (PATTERN (insn), mark_mem_store, NULL); | |
105 | return mem_ref_p; | |
106 | } | |
107 | ||
1ea7e6ad | 108 | /* Returns nonzero if X has access to memory. */ |
d397e8c6 MH |
109 | static bool |
110 | rtx_mem_access_p (rtx x) | |
111 | { | |
112 | int i, j; | |
113 | const char *fmt; | |
114 | enum rtx_code code; | |
115 | ||
116 | if (x == 0) | |
117 | return false; | |
118 | ||
119 | if (GET_CODE (x) == MEM) | |
120 | return true; | |
121 | ||
122 | code = GET_CODE (x); | |
123 | fmt = GET_RTX_FORMAT (code); | |
124 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
125 | { | |
126 | if (fmt[i] == 'e') | |
127 | { | |
128 | if (rtx_mem_access_p (XEXP (x, i))) | |
129 | return true; | |
130 | } | |
131 | else if (fmt[i] == 'E') | |
132 | for (j = 0; j < XVECLEN (x, i); j++) | |
133 | { | |
134 | if (rtx_mem_access_p (XVECEXP (x, i, j))) | |
135 | return true; | |
136 | } | |
137 | } | |
138 | return false; | |
139 | } | |
140 | ||
1ea7e6ad | 141 | /* Returns nonzero if INSN reads to or writes from memory. */ |
d397e8c6 MH |
142 | static bool |
143 | mem_access_insn_p (rtx insn) | |
144 | { | |
145 | return rtx_mem_access_p (PATTERN (insn)); | |
146 | } | |
147 | ||
148 | /* Computes the dependence parameters (latency, distance etc.), creates | |
149 | a ddg_edge and adds it to the given DDG. */ | |
150 | static void | |
151 | create_ddg_dependence (ddg_ptr g, ddg_node_ptr src_node, | |
152 | ddg_node_ptr dest_node, rtx link) | |
153 | { | |
154 | ddg_edge_ptr e; | |
155 | int latency, distance = 0; | |
156 | int interloop = (src_node->cuid >= dest_node->cuid); | |
157 | dep_type t = TRUE_DEP; | |
158 | dep_data_type dt = (mem_access_insn_p (src_node->insn) | |
159 | && mem_access_insn_p (dest_node->insn) ? MEM_DEP | |
160 | : REG_DEP); | |
161 | ||
162 | /* For now we don't have an exact calculation of the distance, | |
163 | so assume 1 conservatively. */ | |
164 | if (interloop) | |
165 | distance = 1; | |
166 | ||
167 | if (!link) | |
168 | abort (); | |
169 | ||
170 | /* Note: REG_DEP_ANTI applies to MEM ANTI_DEP as well!! */ | |
171 | if (REG_NOTE_KIND (link) == REG_DEP_ANTI) | |
172 | t = ANTI_DEP; | |
173 | else if (REG_NOTE_KIND (link) == REG_DEP_OUTPUT) | |
174 | t = OUTPUT_DEP; | |
175 | latency = insn_cost (src_node->insn, link, dest_node->insn); | |
176 | ||
177 | e = create_ddg_edge (src_node, dest_node, t, dt, latency, distance); | |
178 | ||
179 | if (interloop) | |
180 | { | |
181 | /* Some interloop dependencies are relaxed: | |
182 | 1. Every insn is output dependent on itself; ignore such deps. | |
183 | 2. Every true/flow dependence is an anti dependence in the | |
184 | opposite direction with distance 1; such register deps | |
185 | will be removed by renaming if broken --- ignore them. */ | |
186 | if (!(t == OUTPUT_DEP && src_node == dest_node) | |
187 | && !(t == ANTI_DEP && dt == REG_DEP)) | |
188 | add_backarc_to_ddg (g, e); | |
189 | else | |
190 | free (e); | |
191 | } | |
192 | else | |
193 | add_edge_to_ddg (g, e); | |
194 | } | |
195 | ||
196 | /* The same as the above function, but it doesn't require a link parameter. */ | |
197 | static void | |
198 | create_ddg_dep_no_link (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to, | |
199 | dep_type d_t, dep_data_type d_dt, int distance) | |
200 | { | |
201 | ddg_edge_ptr e; | |
202 | int l; | |
203 | rtx link = alloc_INSN_LIST (to->insn, NULL_RTX); | |
204 | ||
205 | if (d_t == ANTI_DEP) | |
206 | PUT_REG_NOTE_KIND (link, REG_DEP_ANTI); | |
207 | else if (d_t == OUTPUT_DEP) | |
208 | PUT_REG_NOTE_KIND (link, REG_DEP_OUTPUT); | |
209 | ||
210 | l = insn_cost (from->insn, link, to->insn); | |
211 | free_INSN_LIST_node (link); | |
212 | ||
213 | e = create_ddg_edge (from, to, d_t, d_dt, l, distance); | |
214 | if (distance > 0) | |
215 | add_backarc_to_ddg (g, e); | |
216 | else | |
217 | add_edge_to_ddg (g, e); | |
218 | } | |
219 | ||
220 | \f | |
221 | /* Given a downwards exposed register def RD, add inter-loop true dependences | |
222 | for all its uses in the next iteration, and an output dependence to the | |
223 | first def of the next iteration. */ | |
224 | static void | |
225 | add_deps_for_def (ddg_ptr g, struct df *df, struct ref *rd) | |
226 | { | |
227 | int regno = DF_REF_REGNO (rd); | |
228 | struct bb_info *bb_info = DF_BB_INFO (df, g->bb); | |
229 | struct df_link *r_use; | |
230 | int use_before_def = false; | |
231 | rtx def_insn = DF_REF_INSN (rd); | |
232 | ddg_node_ptr src_node = get_node_of_insn (g, def_insn); | |
233 | ||
234 | /* Create and inter-loop true dependence between RD and each of its uses | |
235 | that is upwards exposed in RD's block. */ | |
236 | for (r_use = DF_REF_CHAIN (rd); r_use != NULL; r_use = r_use->next) | |
237 | { | |
238 | if (bitmap_bit_p (bb_info->ru_gen, r_use->ref->id)) | |
239 | { | |
240 | rtx use_insn = DF_REF_INSN (r_use->ref); | |
241 | ddg_node_ptr dest_node = get_node_of_insn (g, use_insn); | |
242 | ||
243 | if (!src_node || !dest_node) | |
244 | abort (); | |
245 | ||
246 | /* Any such upwards exposed use appears before the rd def. */ | |
247 | use_before_def = true; | |
248 | create_ddg_dep_no_link (g, src_node, dest_node, TRUE_DEP, | |
249 | REG_DEP, 1); | |
250 | } | |
251 | } | |
252 | ||
253 | /* Create an inter-loop output dependence between RD (which is the | |
254 | last def in its block, being downwards exposed) and the first def | |
255 | in its block. Avoid creating a self output dependence. Avoid creating | |
256 | an output dependence if there is a dependence path between the two defs | |
257 | starting with a true dependence followed by an anti dependence (i.e. if | |
258 | there is a use between the two defs. */ | |
259 | if (! use_before_def) | |
260 | { | |
261 | struct ref *def = df_bb_regno_first_def_find (df, g->bb, regno); | |
262 | int i; | |
263 | ddg_node_ptr dest_node; | |
264 | ||
265 | if (!def || rd->id == def->id) | |
266 | return; | |
267 | ||
268 | /* Check if there are uses after RD. */ | |
269 | for (i = src_node->cuid + 1; i < g->num_nodes; i++) | |
270 | if (df_reg_used (df, g->nodes[i].insn, rd->reg)) | |
271 | return; | |
272 | ||
273 | dest_node = get_node_of_insn (g, def->insn); | |
274 | create_ddg_dep_no_link (g, src_node, dest_node, OUTPUT_DEP, REG_DEP, 1); | |
275 | } | |
276 | } | |
277 | ||
278 | /* Given a register USE, add an inter-loop anti dependence to the first | |
279 | (nearest BLOCK_BEGIN) def of the next iteration, unless USE is followed | |
280 | by a def in the block. */ | |
281 | static void | |
282 | add_deps_for_use (ddg_ptr g, struct df *df, struct ref *use) | |
283 | { | |
284 | int i; | |
285 | int regno = DF_REF_REGNO (use); | |
286 | struct ref *first_def = df_bb_regno_first_def_find (df, g->bb, regno); | |
287 | ddg_node_ptr use_node; | |
288 | ddg_node_ptr def_node; | |
289 | struct bb_info *bb_info; | |
290 | ||
291 | bb_info = DF_BB_INFO (df, g->bb); | |
292 | ||
293 | if (!first_def) | |
294 | return; | |
295 | ||
296 | use_node = get_node_of_insn (g, use->insn); | |
297 | def_node = get_node_of_insn (g, first_def->insn); | |
298 | ||
299 | if (!use_node || !def_node) | |
300 | abort (); | |
301 | ||
302 | /* Make sure there are no defs after USE. */ | |
303 | for (i = use_node->cuid + 1; i < g->num_nodes; i++) | |
304 | if (df_find_def (df, g->nodes[i].insn, use->reg)) | |
305 | return; | |
306 | /* We must not add ANTI dep when there is an intra-loop TRUE dep in | |
307 | the opozite direction. If the first_def reaches the USE then there is | |
308 | such a dep. */ | |
309 | if (! bitmap_bit_p (bb_info->rd_gen, first_def->id)) | |
310 | create_ddg_dep_no_link (g, use_node, def_node, ANTI_DEP, REG_DEP, 1); | |
311 | } | |
312 | ||
313 | /* Build inter-loop dependencies, by looking at DF analysis backwards. */ | |
314 | static void | |
315 | build_inter_loop_deps (ddg_ptr g, struct df *df) | |
316 | { | |
317 | int rd_num, u_num; | |
318 | struct bb_info *bb_info; | |
319 | ||
320 | bb_info = DF_BB_INFO (df, g->bb); | |
321 | ||
322 | /* Find inter-loop output and true deps by connecting downward exposed defs | |
323 | to the first def of the BB and to upwards exposed uses. */ | |
324 | EXECUTE_IF_SET_IN_BITMAP (bb_info->rd_gen, 0, rd_num, | |
325 | { | |
326 | struct ref *rd = df->defs[rd_num]; | |
327 | ||
328 | add_deps_for_def (g, df, rd); | |
329 | }); | |
330 | ||
331 | /* Find inter-loop anti deps. We are interested in uses of the block that | |
332 | appear below all defs; this implies that these uses are killed. */ | |
333 | EXECUTE_IF_SET_IN_BITMAP (bb_info->ru_kill, 0, u_num, | |
334 | { | |
335 | struct ref *use = df->uses[u_num]; | |
336 | ||
337 | /* We are interested in uses of this BB. */ | |
338 | if (BLOCK_FOR_INSN (use->insn) == g->bb) | |
339 | add_deps_for_use (g, df,use); | |
340 | }); | |
341 | } | |
342 | ||
343 | /* Given two nodes, analyze their RTL insns and add inter-loop mem deps | |
344 | to ddg G. */ | |
345 | static void | |
346 | add_inter_loop_mem_dep (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to) | |
347 | { | |
348 | if (mem_write_insn_p (from->insn)) | |
349 | { | |
350 | if (mem_read_insn_p (to->insn)) | |
351 | create_ddg_dep_no_link (g, from, to, TRUE_DEP, MEM_DEP, 1); | |
352 | else if (from->cuid != to->cuid) | |
353 | create_ddg_dep_no_link (g, from, to, OUTPUT_DEP, MEM_DEP, 1); | |
354 | } | |
355 | else | |
356 | { | |
357 | if (mem_read_insn_p (to->insn)) | |
358 | return; | |
359 | else if (from->cuid != to->cuid) | |
360 | { | |
361 | create_ddg_dep_no_link (g, from, to, ANTI_DEP, MEM_DEP, 1); | |
362 | create_ddg_dep_no_link (g, to, from, TRUE_DEP, MEM_DEP, 1); | |
363 | } | |
364 | } | |
365 | ||
366 | } | |
367 | ||
368 | /* Perform intra-block Data Dependency analysis and connect the nodes in | |
369 | the DDG. We assume the loop has a single basic block. */ | |
370 | static void | |
371 | build_intra_loop_deps (ddg_ptr g) | |
372 | { | |
373 | int i; | |
374 | /* Hold the dependency analysis state during dependency calculations. */ | |
375 | struct deps tmp_deps; | |
376 | rtx head, tail, link; | |
377 | ||
378 | /* Build the dependence information, using the sched_analyze function. */ | |
379 | init_deps_global (); | |
380 | init_deps (&tmp_deps); | |
381 | ||
382 | /* Do the intra-block data dependence analysis for the given block. */ | |
383 | get_block_head_tail (g->bb->index, &head, &tail); | |
384 | sched_analyze (&tmp_deps, head, tail); | |
385 | ||
1ea7e6ad | 386 | /* Build intra-loop data dependecies using the scheduler dependecy |
d397e8c6 MH |
387 | analysis. */ |
388 | for (i = 0; i < g->num_nodes; i++) | |
389 | { | |
390 | ddg_node_ptr dest_node = &g->nodes[i]; | |
391 | ||
392 | if (! INSN_P (dest_node->insn)) | |
393 | continue; | |
394 | ||
395 | for (link = LOG_LINKS (dest_node->insn); link; link = XEXP (link, 1)) | |
396 | { | |
397 | ddg_node_ptr src_node = get_node_of_insn (g, XEXP (link, 0)); | |
398 | ||
399 | if (!src_node) | |
400 | continue; | |
401 | ||
402 | add_forward_dependence (XEXP (link, 0), dest_node->insn, | |
403 | REG_NOTE_KIND (link)); | |
404 | create_ddg_dependence (g, src_node, dest_node, | |
405 | INSN_DEPEND (src_node->insn)); | |
406 | } | |
407 | ||
408 | /* If this insn modifies memory, add an edge to all insns that access | |
409 | memory. */ | |
410 | if (mem_access_insn_p (dest_node->insn)) | |
411 | { | |
412 | int j; | |
413 | ||
414 | for (j = 0; j <= i; j++) | |
415 | { | |
416 | ddg_node_ptr j_node = &g->nodes[j]; | |
417 | if (mem_access_insn_p (j_node->insn)) | |
418 | /* Don't bother calculating inter-loop dep if an intra-loop dep | |
419 | already exists. */ | |
420 | if (! TEST_BIT (dest_node->successors, j)) | |
421 | add_inter_loop_mem_dep (g, dest_node, j_node); | |
422 | } | |
423 | } | |
424 | } | |
425 | ||
426 | /* Free the INSN_LISTs. */ | |
427 | finish_deps_global (); | |
428 | free_deps (&tmp_deps); | |
429 | } | |
430 | ||
431 | ||
432 | /* Given a basic block, create its DDG and return a pointer to a variable | |
433 | of ddg type that represents it. | |
434 | Initialize the ddg structure fields to the appropriate values. */ | |
435 | ddg_ptr | |
436 | create_ddg (basic_block bb, struct df *df, int closing_branch_deps) | |
437 | { | |
438 | ddg_ptr g; | |
439 | rtx insn, first_note; | |
440 | int i; | |
441 | int num_nodes = 0; | |
442 | ||
443 | g = (ddg_ptr) xcalloc (1, sizeof (struct ddg)); | |
444 | ||
445 | g->bb = bb; | |
446 | g->closing_branch_deps = closing_branch_deps; | |
447 | ||
448 | /* Count the number of insns in the BB. */ | |
449 | for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); | |
450 | insn = NEXT_INSN (insn)) | |
451 | { | |
452 | if (! INSN_P (insn) || GET_CODE (PATTERN (insn)) == USE) | |
453 | continue; | |
454 | ||
455 | if (mem_read_insn_p (insn)) | |
456 | g->num_loads++; | |
457 | if (mem_write_insn_p (insn)) | |
458 | g->num_stores++; | |
459 | num_nodes++; | |
460 | } | |
461 | ||
462 | /* There is nothing to do for this BB. */ | |
463 | if (num_nodes <= 1) | |
464 | { | |
465 | free (g); | |
466 | return NULL; | |
467 | } | |
468 | ||
469 | /* Allocate the nodes array, and initialize the nodes. */ | |
470 | g->num_nodes = num_nodes; | |
471 | g->nodes = (ddg_node_ptr) xcalloc (num_nodes, sizeof (struct ddg_node)); | |
472 | g->closing_branch = NULL; | |
473 | i = 0; | |
474 | first_note = NULL_RTX; | |
475 | for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); | |
476 | insn = NEXT_INSN (insn)) | |
477 | { | |
478 | if (! INSN_P (insn)) | |
479 | { | |
480 | if (! first_note && GET_CODE (insn) == NOTE | |
481 | && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK) | |
482 | first_note = insn; | |
483 | continue; | |
484 | } | |
485 | if (GET_CODE (insn) == JUMP_INSN) | |
486 | { | |
487 | if (g->closing_branch) | |
488 | abort (); /* Found two branches in DDG. */ | |
489 | else | |
490 | g->closing_branch = &g->nodes[i]; | |
491 | } | |
492 | else if (GET_CODE (PATTERN (insn)) == USE) | |
493 | { | |
494 | if (! first_note) | |
495 | first_note = insn; | |
496 | continue; | |
497 | } | |
498 | ||
499 | g->nodes[i].cuid = i; | |
500 | g->nodes[i].successors = sbitmap_alloc (num_nodes); | |
501 | sbitmap_zero (g->nodes[i].successors); | |
502 | g->nodes[i].predecessors = sbitmap_alloc (num_nodes); | |
503 | sbitmap_zero (g->nodes[i].predecessors); | |
504 | g->nodes[i].first_note = (first_note ? first_note : insn); | |
505 | g->nodes[i++].insn = insn; | |
506 | first_note = NULL_RTX; | |
507 | } | |
508 | ||
509 | if (!g->closing_branch) | |
510 | abort (); /* Found no branch in DDG. */ | |
511 | ||
512 | /* Build the data dependecy graph. */ | |
513 | build_intra_loop_deps (g); | |
514 | build_inter_loop_deps (g, df); | |
515 | return g; | |
516 | } | |
517 | ||
518 | /* Free all the memory allocated for the DDG. */ | |
519 | void | |
520 | free_ddg (ddg_ptr g) | |
521 | { | |
522 | int i; | |
523 | ||
524 | if (!g) | |
525 | return; | |
526 | ||
527 | for (i = 0; i < g->num_nodes; i++) | |
528 | { | |
529 | ddg_edge_ptr e = g->nodes[i].out; | |
530 | ||
531 | while (e) | |
532 | { | |
533 | ddg_edge_ptr next = e->next_out; | |
534 | ||
535 | free (e); | |
536 | e = next; | |
537 | } | |
538 | sbitmap_free (g->nodes[i].successors); | |
539 | sbitmap_free (g->nodes[i].predecessors); | |
540 | } | |
541 | if (g->num_backarcs > 0) | |
542 | free (g->backarcs); | |
543 | free (g->nodes); | |
544 | free (g); | |
545 | } | |
546 | ||
547 | void | |
548 | print_ddg_edge (FILE *dump_file, ddg_edge_ptr e) | |
549 | { | |
550 | char dep_c; | |
551 | ||
552 | switch (e->type) { | |
553 | case OUTPUT_DEP : | |
554 | dep_c = 'O'; | |
555 | break; | |
556 | case ANTI_DEP : | |
557 | dep_c = 'A'; | |
558 | break; | |
559 | default: | |
560 | dep_c = 'T'; | |
561 | } | |
562 | ||
563 | fprintf (dump_file, " [%d -(%c,%d,%d)-> %d] ", INSN_UID (e->src->insn), | |
564 | dep_c, e->latency, e->distance, INSN_UID (e->dest->insn)); | |
565 | } | |
566 | ||
567 | /* Print the DDG nodes with there in/out edges to the dump file. */ | |
568 | void | |
569 | print_ddg (FILE *dump_file, ddg_ptr g) | |
570 | { | |
571 | int i; | |
572 | ||
573 | for (i = 0; i < g->num_nodes; i++) | |
574 | { | |
575 | ddg_edge_ptr e; | |
576 | ||
577 | print_rtl_single (dump_file, g->nodes[i].insn); | |
578 | fprintf (dump_file, "OUT ARCS: "); | |
579 | for (e = g->nodes[i].out; e; e = e->next_out) | |
580 | print_ddg_edge (dump_file, e); | |
581 | ||
582 | fprintf (dump_file, "\nIN ARCS: "); | |
583 | for (e = g->nodes[i].in; e; e = e->next_in) | |
584 | print_ddg_edge (dump_file, e); | |
585 | ||
586 | fprintf (dump_file, "\n"); | |
587 | } | |
588 | } | |
589 | ||
590 | /* Print the given DDG in VCG format. */ | |
591 | void | |
592 | vcg_print_ddg (FILE *dump_file, ddg_ptr g) | |
593 | { | |
594 | int src_cuid; | |
595 | ||
596 | fprintf (dump_file, "graph: {\n"); | |
597 | for (src_cuid = 0; src_cuid < g->num_nodes; src_cuid++) | |
598 | { | |
599 | ddg_edge_ptr e; | |
600 | int src_uid = INSN_UID (g->nodes[src_cuid].insn); | |
601 | ||
602 | fprintf (dump_file, "node: {title: \"%d_%d\" info1: \"", src_cuid, src_uid); | |
603 | print_rtl_single (dump_file, g->nodes[src_cuid].insn); | |
604 | fprintf (dump_file, "\"}\n"); | |
605 | for (e = g->nodes[src_cuid].out; e; e = e->next_out) | |
606 | { | |
607 | int dst_uid = INSN_UID (e->dest->insn); | |
608 | int dst_cuid = e->dest->cuid; | |
609 | ||
610 | /* Give the backarcs a different color. */ | |
611 | if (e->distance > 0) | |
612 | fprintf (dump_file, "backedge: {color: red "); | |
613 | else | |
614 | fprintf (dump_file, "edge: { "); | |
615 | ||
616 | fprintf (dump_file, "sourcename: \"%d_%d\" ", src_cuid, src_uid); | |
617 | fprintf (dump_file, "targetname: \"%d_%d\" ", dst_cuid, dst_uid); | |
618 | fprintf (dump_file, "label: \"%d_%d\"}\n", e->latency, e->distance); | |
619 | } | |
620 | } | |
621 | fprintf (dump_file, "}\n"); | |
622 | } | |
623 | ||
624 | /* Create an edge and initialize it with given values. */ | |
625 | static ddg_edge_ptr | |
626 | create_ddg_edge (ddg_node_ptr src, ddg_node_ptr dest, | |
627 | dep_type t, dep_data_type dt, int l, int d) | |
628 | { | |
629 | ddg_edge_ptr e = (ddg_edge_ptr) xmalloc (sizeof (struct ddg_edge)); | |
630 | ||
631 | e->src = src; | |
632 | e->dest = dest; | |
633 | e->type = t; | |
634 | e->data_type = dt; | |
635 | e->latency = l; | |
636 | e->distance = d; | |
637 | e->next_in = e->next_out = NULL; | |
638 | e->aux.info = 0; | |
639 | return e; | |
640 | } | |
641 | ||
642 | /* Add the given edge to the in/out linked lists of the DDG nodes. */ | |
643 | static void | |
644 | add_edge_to_ddg (ddg_ptr g ATTRIBUTE_UNUSED, ddg_edge_ptr e) | |
645 | { | |
646 | ddg_node_ptr src = e->src; | |
647 | ddg_node_ptr dest = e->dest; | |
648 | ||
649 | if (!src->successors || !dest->predecessors) | |
650 | abort (); /* Should have allocated the sbitmaps. */ | |
651 | ||
652 | SET_BIT (src->successors, dest->cuid); | |
653 | SET_BIT (dest->predecessors, src->cuid); | |
654 | e->next_in = dest->in; | |
655 | dest->in = e; | |
656 | e->next_out = src->out; | |
657 | src->out = e; | |
658 | } | |
659 | ||
660 | ||
661 | \f | |
662 | /* Algorithm for computing the recurrence_length of an scc. We assume at | |
663 | for now that cycles in the data dependence graph contain a single backarc. | |
664 | This simplifies the algorithm, and can be generalized later. */ | |
665 | static void | |
666 | set_recurrence_length (ddg_scc_ptr scc, ddg_ptr g) | |
667 | { | |
668 | int j; | |
669 | int result = -1; | |
670 | ||
671 | for (j = 0; j < scc->num_backarcs; j++) | |
672 | { | |
673 | ddg_edge_ptr backarc = scc->backarcs[j]; | |
674 | int length; | |
675 | int distance = backarc->distance; | |
676 | ddg_node_ptr src = backarc->dest; | |
677 | ddg_node_ptr dest = backarc->src; | |
678 | ||
679 | length = longest_simple_path (g, src->cuid, dest->cuid, scc->nodes); | |
680 | if (length < 0 ) | |
681 | { | |
682 | /* fprintf (stderr, "Backarc not on simple cycle in SCC.\n"); */ | |
683 | continue; | |
684 | } | |
685 | length += backarc->latency; | |
686 | result = MAX (result, (length / distance)); | |
687 | } | |
688 | scc->recurrence_length = result; | |
689 | } | |
690 | ||
691 | /* Create a new SCC given the set of its nodes. Compute its recurrence_length | |
692 | and mark edges that belong to this scc as IN_SCC. */ | |
693 | static ddg_scc_ptr | |
694 | create_scc (ddg_ptr g, sbitmap nodes) | |
695 | { | |
696 | ddg_scc_ptr scc; | |
697 | int u; | |
698 | ||
699 | scc = (ddg_scc_ptr) xmalloc (sizeof (struct ddg_scc)); | |
700 | scc->backarcs = NULL; | |
701 | scc->num_backarcs = 0; | |
702 | scc->nodes = sbitmap_alloc (g->num_nodes); | |
703 | sbitmap_copy (scc->nodes, nodes); | |
704 | ||
705 | /* Mark the backarcs that belong to this SCC. */ | |
706 | EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, u, | |
707 | { | |
708 | ddg_edge_ptr e; | |
709 | ddg_node_ptr n = &g->nodes[u]; | |
710 | ||
711 | for (e = n->out; e; e = e->next_out) | |
712 | if (TEST_BIT (nodes, e->dest->cuid)) | |
713 | { | |
714 | e->aux.count = IN_SCC; | |
715 | if (e->distance > 0) | |
716 | add_backarc_to_scc (scc, e); | |
717 | } | |
718 | }); | |
719 | ||
720 | set_recurrence_length (scc, g); | |
721 | return scc; | |
722 | } | |
723 | ||
724 | /* Cleans the memory allocation of a given SCC. */ | |
725 | static void | |
726 | free_scc (ddg_scc_ptr scc) | |
727 | { | |
728 | if (!scc) | |
729 | return; | |
730 | ||
731 | sbitmap_free (scc->nodes); | |
732 | if (scc->num_backarcs > 0) | |
733 | free (scc->backarcs); | |
734 | free (scc); | |
735 | } | |
736 | ||
737 | ||
738 | /* Add a given edge known to be a backarc to the given DDG. */ | |
739 | static void | |
740 | add_backarc_to_ddg (ddg_ptr g, ddg_edge_ptr e) | |
741 | { | |
742 | int size = (g->num_backarcs + 1) * sizeof (ddg_edge_ptr); | |
743 | ||
744 | add_edge_to_ddg (g, e); | |
745 | g->backarcs = (ddg_edge_ptr *) xrealloc (g->backarcs, size); | |
746 | g->backarcs[g->num_backarcs++] = e; | |
747 | } | |
748 | ||
749 | /* Add backarc to an SCC. */ | |
750 | static void | |
751 | add_backarc_to_scc (ddg_scc_ptr scc, ddg_edge_ptr e) | |
752 | { | |
753 | int size = (scc->num_backarcs + 1) * sizeof (ddg_edge_ptr); | |
754 | ||
755 | scc->backarcs = (ddg_edge_ptr *) xrealloc (scc->backarcs, size); | |
756 | scc->backarcs[scc->num_backarcs++] = e; | |
757 | } | |
758 | ||
759 | /* Add the given SCC to the DDG. */ | |
760 | static void | |
761 | add_scc_to_ddg (ddg_all_sccs_ptr g, ddg_scc_ptr scc) | |
762 | { | |
763 | int size = (g->num_sccs + 1) * sizeof (ddg_scc_ptr); | |
764 | ||
765 | g->sccs = (ddg_scc_ptr *) xrealloc (g->sccs, size); | |
766 | g->sccs[g->num_sccs++] = scc; | |
767 | } | |
768 | ||
769 | /* Given the instruction INSN return the node that represents it. */ | |
770 | ddg_node_ptr | |
771 | get_node_of_insn (ddg_ptr g, rtx insn) | |
772 | { | |
773 | int i; | |
774 | ||
775 | for (i = 0; i < g->num_nodes; i++) | |
776 | if (insn == g->nodes[i].insn) | |
777 | return &g->nodes[i]; | |
778 | return NULL; | |
779 | } | |
780 | ||
781 | /* Given a set OPS of nodes in the DDG, find the set of their successors | |
782 | which are not in OPS, and set their bits in SUCC. Bits corresponding to | |
783 | OPS are cleared from SUCC. Leaves the other bits in SUCC unchanged. */ | |
784 | void | |
785 | find_successors (sbitmap succ, ddg_ptr g, sbitmap ops) | |
786 | { | |
787 | int i; | |
788 | ||
789 | EXECUTE_IF_SET_IN_SBITMAP (ops, 0, i, | |
790 | { | |
791 | const sbitmap node_succ = NODE_SUCCESSORS (&g->nodes[i]); | |
792 | sbitmap_a_or_b (succ, succ, node_succ); | |
793 | }); | |
794 | ||
795 | /* We want those that are not in ops. */ | |
796 | sbitmap_difference (succ, succ, ops); | |
797 | } | |
798 | ||
799 | /* Given a set OPS of nodes in the DDG, find the set of their predecessors | |
800 | which are not in OPS, and set their bits in PREDS. Bits corresponding to | |
801 | OPS are cleared from PREDS. Leaves the other bits in PREDS unchanged. */ | |
802 | void | |
803 | find_predecessors (sbitmap preds, ddg_ptr g, sbitmap ops) | |
804 | { | |
805 | int i; | |
806 | ||
807 | EXECUTE_IF_SET_IN_SBITMAP (ops, 0, i, | |
808 | { | |
809 | const sbitmap node_preds = NODE_PREDECESSORS (&g->nodes[i]); | |
810 | sbitmap_a_or_b (preds, preds, node_preds); | |
811 | }); | |
812 | ||
813 | /* We want those that are not in ops. */ | |
814 | sbitmap_difference (preds, preds, ops); | |
815 | } | |
816 | ||
817 | ||
818 | /* Compare function to be passed to qsort to order the backarcs in descending | |
819 | recMII order. */ | |
820 | static int | |
821 | compare_sccs (const void *s1, const void *s2) | |
822 | { | |
823 | int rec_l1 = (*(ddg_scc_ptr *)s1)->recurrence_length; | |
824 | int rec_l2 = (*(ddg_scc_ptr *)s2)->recurrence_length; | |
825 | return ((rec_l2 > rec_l1) - (rec_l2 < rec_l1)); | |
826 | ||
827 | } | |
828 | ||
829 | /* Order the backarcs in descending recMII order using compare_sccs. */ | |
830 | static void | |
831 | order_sccs (ddg_all_sccs_ptr g) | |
832 | { | |
833 | qsort (g->sccs, g->num_sccs, sizeof (ddg_scc_ptr), | |
834 | (int (*) (const void *, const void *)) compare_sccs); | |
835 | } | |
836 | ||
837 | /* Perform the Strongly Connected Components decomposing algorithm on the | |
838 | DDG and return DDG_ALL_SCCS structure that contains them. */ | |
839 | ddg_all_sccs_ptr | |
840 | create_ddg_all_sccs (ddg_ptr g) | |
841 | { | |
842 | int i; | |
843 | int num_nodes = g->num_nodes; | |
844 | sbitmap from = sbitmap_alloc (num_nodes); | |
845 | sbitmap to = sbitmap_alloc (num_nodes); | |
846 | sbitmap scc_nodes = sbitmap_alloc (num_nodes); | |
847 | ddg_all_sccs_ptr sccs = (ddg_all_sccs_ptr) | |
848 | xmalloc (sizeof (struct ddg_all_sccs)); | |
849 | ||
850 | sccs->ddg = g; | |
851 | sccs->sccs = NULL; | |
852 | sccs->num_sccs = 0; | |
853 | ||
854 | for (i = 0; i < g->num_backarcs; i++) | |
855 | { | |
856 | ddg_scc_ptr scc; | |
857 | ddg_edge_ptr backarc = g->backarcs[i]; | |
858 | ddg_node_ptr src = backarc->src; | |
859 | ddg_node_ptr dest = backarc->dest; | |
860 | ||
861 | /* If the backarc already belongs to an SCC, continue. */ | |
862 | if (backarc->aux.count == IN_SCC) | |
863 | continue; | |
864 | ||
865 | sbitmap_zero (from); | |
866 | sbitmap_zero (to); | |
867 | SET_BIT (from, dest->cuid); | |
868 | SET_BIT (to, src->cuid); | |
869 | ||
870 | if (find_nodes_on_paths (scc_nodes, g, from, to)) | |
871 | { | |
872 | scc = create_scc (g, scc_nodes); | |
873 | add_scc_to_ddg (sccs, scc); | |
874 | } | |
875 | } | |
876 | order_sccs (sccs); | |
877 | sbitmap_free (from); | |
878 | sbitmap_free (to); | |
879 | sbitmap_free (scc_nodes); | |
880 | return sccs; | |
881 | } | |
882 | ||
883 | /* Frees the memory allocated for all SCCs of the DDG, but keeps the DDG. */ | |
884 | void | |
885 | free_ddg_all_sccs (ddg_all_sccs_ptr all_sccs) | |
886 | { | |
887 | int i; | |
888 | ||
889 | if (!all_sccs) | |
890 | return; | |
891 | ||
892 | for (i = 0; i < all_sccs->num_sccs; i++) | |
893 | free_scc (all_sccs->sccs[i]); | |
894 | ||
895 | free (all_sccs); | |
896 | } | |
897 | ||
898 | \f | |
899 | /* Given FROM - a bitmap of source nodes - and TO - a bitmap of destination | |
900 | nodes - find all nodes that lie on paths from FROM to TO (not excluding | |
901 | nodes from FROM and TO). Return non zero if nodes exist. */ | |
902 | int | |
903 | find_nodes_on_paths (sbitmap result, ddg_ptr g, sbitmap from, sbitmap to) | |
904 | { | |
905 | int answer; | |
906 | int change, u; | |
907 | int num_nodes = g->num_nodes; | |
908 | sbitmap workset = sbitmap_alloc (num_nodes); | |
909 | sbitmap reachable_from = sbitmap_alloc (num_nodes); | |
910 | sbitmap reach_to = sbitmap_alloc (num_nodes); | |
911 | sbitmap tmp = sbitmap_alloc (num_nodes); | |
912 | ||
913 | sbitmap_copy (reachable_from, from); | |
914 | sbitmap_copy (tmp, from); | |
915 | ||
916 | change = 1; | |
917 | while (change) | |
918 | { | |
919 | change = 0; | |
920 | sbitmap_copy (workset, tmp); | |
921 | sbitmap_zero (tmp); | |
922 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, | |
923 | { | |
924 | ddg_edge_ptr e; | |
925 | ddg_node_ptr u_node = &g->nodes[u]; | |
926 | ||
927 | for (e = u_node->out; e != (ddg_edge_ptr) 0; e = e->next_out) | |
928 | { | |
929 | ddg_node_ptr v_node = e->dest; | |
930 | int v = v_node->cuid; | |
931 | ||
932 | if (!TEST_BIT (reachable_from, v)) | |
933 | { | |
934 | SET_BIT (reachable_from, v); | |
935 | SET_BIT (tmp, v); | |
936 | change = 1; | |
937 | } | |
938 | } | |
939 | }); | |
940 | } | |
941 | ||
942 | sbitmap_copy (reach_to, to); | |
943 | sbitmap_copy (tmp, to); | |
944 | ||
945 | change = 1; | |
946 | while (change) | |
947 | { | |
948 | change = 0; | |
949 | sbitmap_copy (workset, tmp); | |
950 | sbitmap_zero (tmp); | |
951 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, | |
952 | { | |
953 | ddg_edge_ptr e; | |
954 | ddg_node_ptr u_node = &g->nodes[u]; | |
955 | ||
956 | for (e = u_node->in; e != (ddg_edge_ptr) 0; e = e->next_in) | |
957 | { | |
958 | ddg_node_ptr v_node = e->src; | |
959 | int v = v_node->cuid; | |
960 | ||
961 | if (!TEST_BIT (reach_to, v)) | |
962 | { | |
963 | SET_BIT (reach_to, v); | |
964 | SET_BIT (tmp, v); | |
965 | change = 1; | |
966 | } | |
967 | } | |
968 | }); | |
969 | } | |
970 | ||
971 | answer = sbitmap_a_and_b_cg (result, reachable_from, reach_to); | |
972 | sbitmap_free (workset); | |
973 | sbitmap_free (reachable_from); | |
974 | sbitmap_free (reach_to); | |
975 | sbitmap_free (tmp); | |
976 | return answer; | |
977 | } | |
978 | ||
979 | ||
980 | /* Updates the counts of U_NODE's successors (that belong to NODES) to be | |
981 | at-least as large as the count of U_NODE plus the latency between them. | |
982 | Sets a bit in TMP for each successor whose count was changed (increased). | |
1ea7e6ad | 983 | Returns nonzero if any count was changed. */ |
d397e8c6 MH |
984 | static int |
985 | update_dist_to_successors (ddg_node_ptr u_node, sbitmap nodes, sbitmap tmp) | |
986 | { | |
987 | ddg_edge_ptr e; | |
988 | int result = 0; | |
989 | ||
990 | for (e = u_node->out; e; e = e->next_out) | |
991 | { | |
992 | ddg_node_ptr v_node = e->dest; | |
993 | int v = v_node->cuid; | |
994 | ||
995 | if (TEST_BIT (nodes, v) | |
996 | && (e->distance == 0) | |
997 | && (v_node->aux.count < u_node->aux.count + e->latency)) | |
998 | { | |
999 | v_node->aux.count = u_node->aux.count + e->latency; | |
1000 | SET_BIT (tmp, v); | |
1001 | result = 1; | |
1002 | } | |
1003 | } | |
1004 | return result; | |
1005 | } | |
1006 | ||
1007 | ||
1008 | /* Find the length of a longest path from SRC to DEST in G, | |
1009 | going only through NODES, and disregarding backarcs. */ | |
1010 | int | |
1011 | longest_simple_path (struct ddg * g, int src, int dest, sbitmap nodes) | |
1012 | { | |
1013 | int i, u; | |
1014 | int change = 1; | |
1015 | int result; | |
1016 | int num_nodes = g->num_nodes; | |
1017 | sbitmap workset = sbitmap_alloc (num_nodes); | |
1018 | sbitmap tmp = sbitmap_alloc (num_nodes); | |
1019 | ||
1020 | ||
1021 | /* Data will hold the distance of the longest path found so far from | |
1022 | src to each node. Initialize to -1 = less than minimum. */ | |
1023 | for (i = 0; i < g->num_nodes; i++) | |
1024 | g->nodes[i].aux.count = -1; | |
1025 | g->nodes[src].aux.count = 0; | |
1026 | ||
1027 | sbitmap_zero (tmp); | |
1028 | SET_BIT (tmp, src); | |
1029 | ||
1030 | while (change) | |
1031 | { | |
1032 | change = 0; | |
1033 | sbitmap_copy (workset, tmp); | |
1034 | sbitmap_zero (tmp); | |
1035 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, | |
1036 | { | |
1037 | ddg_node_ptr u_node = &g->nodes[u]; | |
1038 | ||
1039 | change |= update_dist_to_successors (u_node, nodes, tmp); | |
1040 | }); | |
1041 | } | |
1042 | result = g->nodes[dest].aux.count; | |
1043 | sbitmap_free (workset); | |
1044 | sbitmap_free (tmp); | |
1045 | return result; | |
1046 | } |