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d397e8c6 | 1 | /* DDG - Data Dependence Graph implementation. |
6fb5fa3c | 2 | Copyright (C) 2004, 2005, 2006, 2007 |
d397e8c6 MH |
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 | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
d397e8c6 MH |
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 | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
d397e8c6 MH |
21 | |
22 | ||
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
26 | #include "tm.h" | |
27 | #include "toplev.h" | |
28 | #include "rtl.h" | |
29 | #include "tm_p.h" | |
30 | #include "hard-reg-set.h" | |
d397e8c6 MH |
31 | #include "regs.h" |
32 | #include "function.h" | |
33 | #include "flags.h" | |
34 | #include "insn-config.h" | |
35 | #include "insn-attr.h" | |
36 | #include "except.h" | |
37 | #include "recog.h" | |
38 | #include "sched-int.h" | |
39 | #include "target.h" | |
40 | #include "cfglayout.h" | |
41 | #include "cfgloop.h" | |
42 | #include "sbitmap.h" | |
43 | #include "expr.h" | |
44 | #include "bitmap.h" | |
d397e8c6 MH |
45 | #include "ddg.h" |
46 | ||
47 | /* A flag indicating that a ddg edge belongs to an SCC or not. */ | |
48 | enum edge_flag {NOT_IN_SCC = 0, IN_SCC}; | |
49 | ||
50 | /* Forward declarations. */ | |
51 | static void add_backarc_to_ddg (ddg_ptr, ddg_edge_ptr); | |
52 | static void add_backarc_to_scc (ddg_scc_ptr, ddg_edge_ptr); | |
53 | static void add_scc_to_ddg (ddg_all_sccs_ptr, ddg_scc_ptr); | |
517d76fa VY |
54 | static void create_ddg_dep_from_intra_loop_link (ddg_ptr, ddg_node_ptr, |
55 | ddg_node_ptr, dep_t); | |
d397e8c6 MH |
56 | static void create_ddg_dep_no_link (ddg_ptr, ddg_node_ptr, ddg_node_ptr, |
57 | dep_type, dep_data_type, int); | |
58 | static ddg_edge_ptr create_ddg_edge (ddg_node_ptr, ddg_node_ptr, dep_type, | |
59 | dep_data_type, int, int); | |
60 | static void add_edge_to_ddg (ddg_ptr g, ddg_edge_ptr); | |
61 | \f | |
62 | /* Auxiliary variable for mem_read_insn_p/mem_write_insn_p. */ | |
63 | static bool mem_ref_p; | |
64 | ||
65 | /* Auxiliary function for mem_read_insn_p. */ | |
66 | static int | |
67 | mark_mem_use (rtx *x, void *data ATTRIBUTE_UNUSED) | |
68 | { | |
d9c4ef55 | 69 | if (MEM_P (*x)) |
d397e8c6 MH |
70 | mem_ref_p = true; |
71 | return 0; | |
72 | } | |
73 | ||
74 | /* Auxiliary function for mem_read_insn_p. */ | |
75 | static void | |
76 | mark_mem_use_1 (rtx *x, void *data) | |
77 | { | |
78 | for_each_rtx (x, mark_mem_use, data); | |
79 | } | |
80 | ||
1ea7e6ad | 81 | /* Returns nonzero if INSN reads from memory. */ |
d397e8c6 MH |
82 | static bool |
83 | mem_read_insn_p (rtx insn) | |
84 | { | |
85 | mem_ref_p = false; | |
86 | note_uses (&PATTERN (insn), mark_mem_use_1, NULL); | |
87 | return mem_ref_p; | |
88 | } | |
89 | ||
90 | static void | |
7bc980e1 | 91 | mark_mem_store (rtx loc, const_rtx setter ATTRIBUTE_UNUSED, void *data ATTRIBUTE_UNUSED) |
d397e8c6 | 92 | { |
d9c4ef55 | 93 | if (MEM_P (loc)) |
d397e8c6 MH |
94 | mem_ref_p = true; |
95 | } | |
96 | ||
1ea7e6ad | 97 | /* Returns nonzero if INSN writes to memory. */ |
d397e8c6 MH |
98 | static bool |
99 | mem_write_insn_p (rtx insn) | |
100 | { | |
101 | mem_ref_p = false; | |
102 | note_stores (PATTERN (insn), mark_mem_store, NULL); | |
103 | return mem_ref_p; | |
104 | } | |
105 | ||
1ea7e6ad | 106 | /* Returns nonzero if X has access to memory. */ |
d397e8c6 MH |
107 | static bool |
108 | rtx_mem_access_p (rtx x) | |
109 | { | |
110 | int i, j; | |
111 | const char *fmt; | |
112 | enum rtx_code code; | |
113 | ||
114 | if (x == 0) | |
115 | return false; | |
116 | ||
d9c4ef55 | 117 | if (MEM_P (x)) |
d397e8c6 MH |
118 | return true; |
119 | ||
120 | code = GET_CODE (x); | |
121 | fmt = GET_RTX_FORMAT (code); | |
122 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
123 | { | |
124 | if (fmt[i] == 'e') | |
125 | { | |
126 | if (rtx_mem_access_p (XEXP (x, i))) | |
127 | return true; | |
128 | } | |
129 | else if (fmt[i] == 'E') | |
130 | for (j = 0; j < XVECLEN (x, i); j++) | |
131 | { | |
132 | if (rtx_mem_access_p (XVECEXP (x, i, j))) | |
133 | return true; | |
134 | } | |
135 | } | |
136 | return false; | |
137 | } | |
138 | ||
1ea7e6ad | 139 | /* Returns nonzero if INSN reads to or writes from memory. */ |
d397e8c6 MH |
140 | static bool |
141 | mem_access_insn_p (rtx insn) | |
142 | { | |
143 | return rtx_mem_access_p (PATTERN (insn)); | |
144 | } | |
145 | ||
146 | /* Computes the dependence parameters (latency, distance etc.), creates | |
147 | a ddg_edge and adds it to the given DDG. */ | |
148 | static void | |
517d76fa VY |
149 | create_ddg_dep_from_intra_loop_link (ddg_ptr g, ddg_node_ptr src_node, |
150 | ddg_node_ptr dest_node, dep_t link) | |
d397e8c6 MH |
151 | { |
152 | ddg_edge_ptr e; | |
153 | int latency, distance = 0; | |
d397e8c6 MH |
154 | dep_type t = TRUE_DEP; |
155 | dep_data_type dt = (mem_access_insn_p (src_node->insn) | |
156 | && mem_access_insn_p (dest_node->insn) ? MEM_DEP | |
157 | : REG_DEP); | |
517d76fa | 158 | gcc_assert (src_node->cuid < dest_node->cuid); |
ced3f397 | 159 | gcc_assert (link); |
d397e8c6 MH |
160 | |
161 | /* Note: REG_DEP_ANTI applies to MEM ANTI_DEP as well!! */ | |
e2f6ff94 | 162 | if (DEP_TYPE (link) == REG_DEP_ANTI) |
d397e8c6 | 163 | t = ANTI_DEP; |
e2f6ff94 | 164 | else if (DEP_TYPE (link) == REG_DEP_OUTPUT) |
d397e8c6 | 165 | t = OUTPUT_DEP; |
d397e8c6 | 166 | |
517d76fa VY |
167 | /* We currently choose not to create certain anti-deps edges and |
168 | compensate for that by generating reg-moves based on the life-range | |
169 | analysis. The anti-deps that will be deleted are the ones which | |
170 | have true-deps edges in the opposite direction (in other words | |
171 | the kernel has only one def of the relevant register). TODO: | |
172 | support the removal of all anti-deps edges, i.e. including those | |
173 | whose register has multiple defs in the loop. */ | |
174 | if (flag_modulo_sched_allow_regmoves && (t == ANTI_DEP && dt == REG_DEP)) | |
d397e8c6 | 175 | { |
517d76fa VY |
176 | rtx set; |
177 | ||
178 | set = single_set (dest_node->insn); | |
179 | if (set) | |
180 | { | |
181 | int regno = REGNO (SET_DEST (set)); | |
182 | struct df_ref *first_def = | |
183 | df_bb_regno_first_def_find (g->bb, regno); | |
184 | struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (g->bb); | |
185 | ||
186 | if (bitmap_bit_p (bb_info->gen, first_def->id)) | |
187 | return; | |
188 | } | |
d397e8c6 | 189 | } |
517d76fa VY |
190 | |
191 | latency = dep_cost (link); | |
192 | e = create_ddg_edge (src_node, dest_node, t, dt, latency, distance); | |
193 | add_edge_to_ddg (g, e); | |
d397e8c6 MH |
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; | |
b198261f MK |
203 | enum reg_note dep_kind; |
204 | struct _dep _dep, *dep = &_dep; | |
d397e8c6 MH |
205 | |
206 | if (d_t == ANTI_DEP) | |
b198261f | 207 | dep_kind = REG_DEP_ANTI; |
d397e8c6 | 208 | else if (d_t == OUTPUT_DEP) |
b198261f MK |
209 | dep_kind = REG_DEP_OUTPUT; |
210 | else | |
211 | { | |
212 | gcc_assert (d_t == TRUE_DEP); | |
213 | ||
214 | dep_kind = REG_DEP_TRUE; | |
215 | } | |
216 | ||
217 | init_dep (dep, from->insn, to->insn, dep_kind); | |
d397e8c6 | 218 | |
b198261f | 219 | l = dep_cost (dep); |
d397e8c6 MH |
220 | |
221 | e = create_ddg_edge (from, to, d_t, d_dt, l, distance); | |
222 | if (distance > 0) | |
223 | add_backarc_to_ddg (g, e); | |
224 | else | |
225 | add_edge_to_ddg (g, e); | |
226 | } | |
227 | ||
e0ab232e RE |
228 | |
229 | /* Given a downwards exposed register def LAST_DEF (which is the last | |
230 | definition of that register in the bb), add inter-loop true dependences | |
231 | to all its uses in the next iteration, an output dependence to the | |
232 | first def of the same register (possibly itself) in the next iteration | |
233 | and anti-dependences from its uses in the current iteration to the | |
234 | first definition in the next iteration. */ | |
d397e8c6 | 235 | static void |
e0ab232e | 236 | add_cross_iteration_register_deps (ddg_ptr g, struct df_ref *last_def) |
d397e8c6 | 237 | { |
e0ab232e | 238 | int regno = DF_REF_REGNO (last_def); |
d397e8c6 | 239 | struct df_link *r_use; |
e0ab232e RE |
240 | int has_use_in_bb_p = false; |
241 | rtx def_insn = DF_REF_INSN (last_def); | |
242 | ddg_node_ptr last_def_node = get_node_of_insn (g, def_insn); | |
243 | ddg_node_ptr use_node; | |
e439ba28 | 244 | #ifdef ENABLE_CHECKING |
e0ab232e | 245 | struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (g->bb); |
e439ba28 | 246 | #endif |
e0ab232e | 247 | struct df_ref *first_def = df_bb_regno_first_def_find (g->bb, regno); |
d397e8c6 | 248 | |
e0ab232e RE |
249 | gcc_assert (last_def_node); |
250 | gcc_assert (first_def); | |
251 | ||
517d76fa VY |
252 | #ifdef ENABLE_CHECKING |
253 | if (last_def->id != first_def->id) | |
254 | gcc_assert (!bitmap_bit_p (bb_info->gen, first_def->id)); | |
255 | #endif | |
256 | ||
e0ab232e RE |
257 | /* Create inter-loop true dependences and anti dependences. */ |
258 | for (r_use = DF_REF_CHAIN (last_def); r_use != NULL; r_use = r_use->next) | |
d397e8c6 | 259 | { |
e0ab232e | 260 | rtx use_insn = DF_REF_INSN (r_use->ref); |
d397e8c6 | 261 | |
e0ab232e RE |
262 | if (BLOCK_FOR_INSN (use_insn) != g->bb) |
263 | continue; | |
d397e8c6 | 264 | |
e0ab232e RE |
265 | /* ??? Do not handle uses with DF_REF_IN_NOTE notes. */ |
266 | use_node = get_node_of_insn (g, use_insn); | |
267 | gcc_assert (use_node); | |
268 | has_use_in_bb_p = true; | |
269 | if (use_node->cuid <= last_def_node->cuid) | |
270 | { | |
271 | /* Add true deps from last_def to it's uses in the next | |
272 | iteration. Any such upwards exposed use appears before | |
273 | the last_def def. */ | |
274 | create_ddg_dep_no_link (g, last_def_node, use_node, TRUE_DEP, | |
d397e8c6 MH |
275 | REG_DEP, 1); |
276 | } | |
e0ab232e RE |
277 | else |
278 | { | |
279 | /* Add anti deps from last_def's uses in the current iteration | |
280 | to the first def in the next iteration. We do not add ANTI | |
281 | dep when there is an intra-loop TRUE dep in the opposite | |
282 | direction, but use regmoves to fix such disregarded ANTI | |
283 | deps when broken. If the first_def reaches the USE then | |
284 | there is such a dep. */ | |
285 | ddg_node_ptr first_def_node = get_node_of_insn (g, | |
286 | first_def->insn); | |
287 | ||
288 | gcc_assert (first_def_node); | |
289 | ||
517d76fa VY |
290 | if (last_def->id != first_def->id |
291 | || !flag_modulo_sched_allow_regmoves) | |
292 | create_ddg_dep_no_link (g, use_node, first_def_node, ANTI_DEP, | |
293 | REG_DEP, 1); | |
294 | ||
e0ab232e | 295 | } |
d397e8c6 | 296 | } |
e0ab232e RE |
297 | /* Create an inter-loop output dependence between LAST_DEF (which is the |
298 | last def in its block, being downwards exposed) and the first def in | |
299 | its block. Avoid creating a self output dependence. Avoid creating | |
300 | an output dependence if there is a dependence path between the two | |
301 | defs starting with a true dependence to a use which can be in the | |
302 | next iteration; followed by an anti dependence of that use to the | |
303 | first def (i.e. if there is a use between the two defs.) */ | |
304 | if (!has_use_in_bb_p) | |
d397e8c6 | 305 | { |
d397e8c6 MH |
306 | ddg_node_ptr dest_node; |
307 | ||
e0ab232e | 308 | if (last_def->id == first_def->id) |
d397e8c6 MH |
309 | return; |
310 | ||
e0ab232e RE |
311 | dest_node = get_node_of_insn (g, first_def->insn); |
312 | gcc_assert (dest_node); | |
313 | create_ddg_dep_no_link (g, last_def_node, dest_node, | |
314 | OUTPUT_DEP, REG_DEP, 1); | |
d397e8c6 MH |
315 | } |
316 | } | |
d397e8c6 MH |
317 | /* Build inter-loop dependencies, by looking at DF analysis backwards. */ |
318 | static void | |
6fb5fa3c | 319 | build_inter_loop_deps (ddg_ptr g) |
d397e8c6 | 320 | { |
e0ab232e | 321 | unsigned rd_num; |
4d779342 | 322 | struct df_rd_bb_info *rd_bb_info; |
87c476a2 | 323 | bitmap_iterator bi; |
d397e8c6 | 324 | |
6fb5fa3c | 325 | rd_bb_info = DF_RD_BB_INFO (g->bb); |
d397e8c6 | 326 | |
e0ab232e | 327 | /* Find inter-loop register output, true and anti deps. */ |
4d779342 | 328 | EXECUTE_IF_SET_IN_BITMAP (rd_bb_info->gen, 0, rd_num, bi) |
e0ab232e RE |
329 | { |
330 | struct df_ref *rd = DF_DEFS_GET (rd_num); | |
4d779342 | 331 | |
e0ab232e RE |
332 | add_cross_iteration_register_deps (g, rd); |
333 | } | |
d397e8c6 MH |
334 | } |
335 | ||
e0ab232e | 336 | |
d397e8c6 MH |
337 | /* Given two nodes, analyze their RTL insns and add inter-loop mem deps |
338 | to ddg G. */ | |
339 | static void | |
340 | add_inter_loop_mem_dep (ddg_ptr g, ddg_node_ptr from, ddg_node_ptr to) | |
341 | { | |
342 | if (mem_write_insn_p (from->insn)) | |
343 | { | |
344 | if (mem_read_insn_p (to->insn)) | |
345 | create_ddg_dep_no_link (g, from, to, TRUE_DEP, MEM_DEP, 1); | |
346 | else if (from->cuid != to->cuid) | |
347 | create_ddg_dep_no_link (g, from, to, OUTPUT_DEP, MEM_DEP, 1); | |
348 | } | |
349 | else | |
350 | { | |
351 | if (mem_read_insn_p (to->insn)) | |
352 | return; | |
353 | else if (from->cuid != to->cuid) | |
354 | { | |
355 | create_ddg_dep_no_link (g, from, to, ANTI_DEP, MEM_DEP, 1); | |
356 | create_ddg_dep_no_link (g, to, from, TRUE_DEP, MEM_DEP, 1); | |
357 | } | |
358 | } | |
359 | ||
360 | } | |
361 | ||
362 | /* Perform intra-block Data Dependency analysis and connect the nodes in | |
9cf737f8 | 363 | the DDG. We assume the loop has a single basic block. */ |
d397e8c6 MH |
364 | static void |
365 | build_intra_loop_deps (ddg_ptr g) | |
366 | { | |
367 | int i; | |
368 | /* Hold the dependency analysis state during dependency calculations. */ | |
369 | struct deps tmp_deps; | |
b198261f | 370 | rtx head, tail; |
d397e8c6 MH |
371 | |
372 | /* Build the dependence information, using the sched_analyze function. */ | |
373 | init_deps_global (); | |
374 | init_deps (&tmp_deps); | |
375 | ||
376 | /* Do the intra-block data dependence analysis for the given block. */ | |
496d7bb0 | 377 | get_ebb_head_tail (g->bb, g->bb, &head, &tail); |
d397e8c6 MH |
378 | sched_analyze (&tmp_deps, head, tail); |
379 | ||
61ada8ae | 380 | /* Build intra-loop data dependencies using the scheduler dependency |
d397e8c6 MH |
381 | analysis. */ |
382 | for (i = 0; i < g->num_nodes; i++) | |
383 | { | |
384 | ddg_node_ptr dest_node = &g->nodes[i]; | |
e2f6ff94 MK |
385 | sd_iterator_def sd_it; |
386 | dep_t dep; | |
d397e8c6 MH |
387 | |
388 | if (! INSN_P (dest_node->insn)) | |
389 | continue; | |
390 | ||
e2f6ff94 | 391 | FOR_EACH_DEP (dest_node->insn, SD_LIST_BACK, sd_it, dep) |
d397e8c6 | 392 | { |
b198261f | 393 | ddg_node_ptr src_node = get_node_of_insn (g, DEP_PRO (dep)); |
d397e8c6 MH |
394 | |
395 | if (!src_node) | |
396 | continue; | |
397 | ||
517d76fa | 398 | create_ddg_dep_from_intra_loop_link (g, src_node, dest_node, dep); |
d397e8c6 MH |
399 | } |
400 | ||
401 | /* If this insn modifies memory, add an edge to all insns that access | |
402 | memory. */ | |
403 | if (mem_access_insn_p (dest_node->insn)) | |
404 | { | |
405 | int j; | |
406 | ||
407 | for (j = 0; j <= i; j++) | |
408 | { | |
409 | ddg_node_ptr j_node = &g->nodes[j]; | |
410 | if (mem_access_insn_p (j_node->insn)) | |
411 | /* Don't bother calculating inter-loop dep if an intra-loop dep | |
412 | already exists. */ | |
413 | if (! TEST_BIT (dest_node->successors, j)) | |
414 | add_inter_loop_mem_dep (g, dest_node, j_node); | |
415 | } | |
416 | } | |
417 | } | |
418 | ||
419 | /* Free the INSN_LISTs. */ | |
420 | finish_deps_global (); | |
421 | free_deps (&tmp_deps); | |
e2f6ff94 MK |
422 | |
423 | /* Free dependencies. */ | |
424 | sched_free_deps (head, tail, false); | |
d397e8c6 MH |
425 | } |
426 | ||
427 | ||
428 | /* Given a basic block, create its DDG and return a pointer to a variable | |
429 | of ddg type that represents it. | |
430 | Initialize the ddg structure fields to the appropriate values. */ | |
431 | ddg_ptr | |
6fb5fa3c | 432 | create_ddg (basic_block bb, int closing_branch_deps) |
d397e8c6 MH |
433 | { |
434 | ddg_ptr g; | |
435 | rtx insn, first_note; | |
436 | int i; | |
437 | int num_nodes = 0; | |
438 | ||
439 | g = (ddg_ptr) xcalloc (1, sizeof (struct ddg)); | |
440 | ||
441 | g->bb = bb; | |
442 | g->closing_branch_deps = closing_branch_deps; | |
443 | ||
444 | /* Count the number of insns in the BB. */ | |
445 | for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); | |
446 | insn = NEXT_INSN (insn)) | |
447 | { | |
448 | if (! INSN_P (insn) || GET_CODE (PATTERN (insn)) == USE) | |
449 | continue; | |
450 | ||
451 | if (mem_read_insn_p (insn)) | |
452 | g->num_loads++; | |
453 | if (mem_write_insn_p (insn)) | |
454 | g->num_stores++; | |
455 | num_nodes++; | |
456 | } | |
457 | ||
458 | /* There is nothing to do for this BB. */ | |
459 | if (num_nodes <= 1) | |
460 | { | |
461 | free (g); | |
462 | return NULL; | |
463 | } | |
464 | ||
465 | /* Allocate the nodes array, and initialize the nodes. */ | |
466 | g->num_nodes = num_nodes; | |
467 | g->nodes = (ddg_node_ptr) xcalloc (num_nodes, sizeof (struct ddg_node)); | |
468 | g->closing_branch = NULL; | |
469 | i = 0; | |
470 | first_note = NULL_RTX; | |
471 | for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); | |
472 | insn = NEXT_INSN (insn)) | |
473 | { | |
474 | if (! INSN_P (insn)) | |
475 | { | |
4b4bf941 | 476 | if (! first_note && NOTE_P (insn) |
a38e7aa5 | 477 | && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK) |
d397e8c6 MH |
478 | first_note = insn; |
479 | continue; | |
480 | } | |
4b4bf941 | 481 | if (JUMP_P (insn)) |
d397e8c6 | 482 | { |
ced3f397 NS |
483 | gcc_assert (!g->closing_branch); |
484 | g->closing_branch = &g->nodes[i]; | |
d397e8c6 MH |
485 | } |
486 | else if (GET_CODE (PATTERN (insn)) == USE) | |
487 | { | |
488 | if (! first_note) | |
489 | first_note = insn; | |
490 | continue; | |
491 | } | |
492 | ||
493 | g->nodes[i].cuid = i; | |
494 | g->nodes[i].successors = sbitmap_alloc (num_nodes); | |
495 | sbitmap_zero (g->nodes[i].successors); | |
496 | g->nodes[i].predecessors = sbitmap_alloc (num_nodes); | |
497 | sbitmap_zero (g->nodes[i].predecessors); | |
498 | g->nodes[i].first_note = (first_note ? first_note : insn); | |
499 | g->nodes[i++].insn = insn; | |
500 | first_note = NULL_RTX; | |
501 | } | |
ced3f397 NS |
502 | |
503 | /* We must have found a branch in DDG. */ | |
504 | gcc_assert (g->closing_branch); | |
505 | ||
d397e8c6 | 506 | |
61ada8ae | 507 | /* Build the data dependency graph. */ |
d397e8c6 | 508 | build_intra_loop_deps (g); |
6fb5fa3c | 509 | build_inter_loop_deps (g); |
d397e8c6 MH |
510 | return g; |
511 | } | |
512 | ||
513 | /* Free all the memory allocated for the DDG. */ | |
514 | void | |
515 | free_ddg (ddg_ptr g) | |
516 | { | |
517 | int i; | |
518 | ||
519 | if (!g) | |
520 | return; | |
521 | ||
522 | for (i = 0; i < g->num_nodes; i++) | |
523 | { | |
524 | ddg_edge_ptr e = g->nodes[i].out; | |
525 | ||
526 | while (e) | |
527 | { | |
528 | ddg_edge_ptr next = e->next_out; | |
529 | ||
530 | free (e); | |
531 | e = next; | |
532 | } | |
533 | sbitmap_free (g->nodes[i].successors); | |
534 | sbitmap_free (g->nodes[i].predecessors); | |
535 | } | |
536 | if (g->num_backarcs > 0) | |
537 | free (g->backarcs); | |
538 | free (g->nodes); | |
539 | free (g); | |
540 | } | |
541 | ||
542 | void | |
10d22567 | 543 | print_ddg_edge (FILE *file, ddg_edge_ptr e) |
d397e8c6 MH |
544 | { |
545 | char dep_c; | |
546 | ||
428aba16 RS |
547 | switch (e->type) |
548 | { | |
d397e8c6 MH |
549 | case OUTPUT_DEP : |
550 | dep_c = 'O'; | |
551 | break; | |
552 | case ANTI_DEP : | |
553 | dep_c = 'A'; | |
554 | break; | |
555 | default: | |
556 | dep_c = 'T'; | |
428aba16 | 557 | } |
d397e8c6 | 558 | |
10d22567 | 559 | fprintf (file, " [%d -(%c,%d,%d)-> %d] ", INSN_UID (e->src->insn), |
d397e8c6 MH |
560 | dep_c, e->latency, e->distance, INSN_UID (e->dest->insn)); |
561 | } | |
562 | ||
563 | /* Print the DDG nodes with there in/out edges to the dump file. */ | |
564 | void | |
10d22567 | 565 | print_ddg (FILE *file, ddg_ptr g) |
d397e8c6 MH |
566 | { |
567 | int i; | |
568 | ||
569 | for (i = 0; i < g->num_nodes; i++) | |
570 | { | |
571 | ddg_edge_ptr e; | |
572 | ||
76b4f0f7 | 573 | fprintf (file, "Node num: %d\n", g->nodes[i].cuid); |
10d22567 ZD |
574 | print_rtl_single (file, g->nodes[i].insn); |
575 | fprintf (file, "OUT ARCS: "); | |
d397e8c6 | 576 | for (e = g->nodes[i].out; e; e = e->next_out) |
10d22567 | 577 | print_ddg_edge (file, e); |
d397e8c6 | 578 | |
10d22567 | 579 | fprintf (file, "\nIN ARCS: "); |
d397e8c6 | 580 | for (e = g->nodes[i].in; e; e = e->next_in) |
10d22567 | 581 | print_ddg_edge (file, e); |
d397e8c6 | 582 | |
10d22567 | 583 | fprintf (file, "\n"); |
d397e8c6 MH |
584 | } |
585 | } | |
586 | ||
587 | /* Print the given DDG in VCG format. */ | |
588 | void | |
10d22567 | 589 | vcg_print_ddg (FILE *file, ddg_ptr g) |
d397e8c6 MH |
590 | { |
591 | int src_cuid; | |
592 | ||
10d22567 | 593 | fprintf (file, "graph: {\n"); |
d397e8c6 MH |
594 | for (src_cuid = 0; src_cuid < g->num_nodes; src_cuid++) |
595 | { | |
596 | ddg_edge_ptr e; | |
597 | int src_uid = INSN_UID (g->nodes[src_cuid].insn); | |
598 | ||
10d22567 ZD |
599 | fprintf (file, "node: {title: \"%d_%d\" info1: \"", src_cuid, src_uid); |
600 | print_rtl_single (file, g->nodes[src_cuid].insn); | |
601 | fprintf (file, "\"}\n"); | |
d397e8c6 MH |
602 | for (e = g->nodes[src_cuid].out; e; e = e->next_out) |
603 | { | |
604 | int dst_uid = INSN_UID (e->dest->insn); | |
605 | int dst_cuid = e->dest->cuid; | |
606 | ||
607 | /* Give the backarcs a different color. */ | |
608 | if (e->distance > 0) | |
10d22567 | 609 | fprintf (file, "backedge: {color: red "); |
d397e8c6 | 610 | else |
10d22567 | 611 | fprintf (file, "edge: { "); |
d397e8c6 | 612 | |
10d22567 ZD |
613 | fprintf (file, "sourcename: \"%d_%d\" ", src_cuid, src_uid); |
614 | fprintf (file, "targetname: \"%d_%d\" ", dst_cuid, dst_uid); | |
615 | fprintf (file, "label: \"%d_%d\"}\n", e->latency, e->distance); | |
d397e8c6 MH |
616 | } |
617 | } | |
10d22567 | 618 | fprintf (file, "}\n"); |
d397e8c6 MH |
619 | } |
620 | ||
8cec1624 RE |
621 | /* Dump the sccs in SCCS. */ |
622 | void | |
623 | print_sccs (FILE *file, ddg_all_sccs_ptr sccs, ddg_ptr g) | |
624 | { | |
625 | unsigned int u = 0; | |
626 | sbitmap_iterator sbi; | |
627 | int i; | |
628 | ||
629 | if (!file) | |
630 | return; | |
631 | ||
632 | fprintf (file, "\n;; Number of SCC nodes - %d\n", sccs->num_sccs); | |
633 | for (i = 0; i < sccs->num_sccs; i++) | |
634 | { | |
635 | fprintf (file, "SCC number: %d\n", i); | |
636 | EXECUTE_IF_SET_IN_SBITMAP (sccs->sccs[i]->nodes, 0, u, sbi) | |
637 | { | |
638 | fprintf (file, "insn num %d\n", u); | |
639 | print_rtl_single (file, g->nodes[u].insn); | |
640 | } | |
641 | } | |
642 | fprintf (file, "\n"); | |
643 | } | |
644 | ||
d397e8c6 MH |
645 | /* Create an edge and initialize it with given values. */ |
646 | static ddg_edge_ptr | |
647 | create_ddg_edge (ddg_node_ptr src, ddg_node_ptr dest, | |
648 | dep_type t, dep_data_type dt, int l, int d) | |
649 | { | |
650 | ddg_edge_ptr e = (ddg_edge_ptr) xmalloc (sizeof (struct ddg_edge)); | |
651 | ||
652 | e->src = src; | |
653 | e->dest = dest; | |
654 | e->type = t; | |
655 | e->data_type = dt; | |
656 | e->latency = l; | |
657 | e->distance = d; | |
658 | e->next_in = e->next_out = NULL; | |
659 | e->aux.info = 0; | |
660 | return e; | |
661 | } | |
662 | ||
663 | /* Add the given edge to the in/out linked lists of the DDG nodes. */ | |
664 | static void | |
665 | add_edge_to_ddg (ddg_ptr g ATTRIBUTE_UNUSED, ddg_edge_ptr e) | |
666 | { | |
667 | ddg_node_ptr src = e->src; | |
668 | ddg_node_ptr dest = e->dest; | |
669 | ||
ced3f397 NS |
670 | /* Should have allocated the sbitmaps. */ |
671 | gcc_assert (src->successors && dest->predecessors); | |
d397e8c6 MH |
672 | |
673 | SET_BIT (src->successors, dest->cuid); | |
674 | SET_BIT (dest->predecessors, src->cuid); | |
675 | e->next_in = dest->in; | |
676 | dest->in = e; | |
677 | e->next_out = src->out; | |
678 | src->out = e; | |
679 | } | |
680 | ||
681 | ||
682 | \f | |
683 | /* Algorithm for computing the recurrence_length of an scc. We assume at | |
684 | for now that cycles in the data dependence graph contain a single backarc. | |
685 | This simplifies the algorithm, and can be generalized later. */ | |
686 | static void | |
687 | set_recurrence_length (ddg_scc_ptr scc, ddg_ptr g) | |
688 | { | |
689 | int j; | |
690 | int result = -1; | |
691 | ||
692 | for (j = 0; j < scc->num_backarcs; j++) | |
693 | { | |
694 | ddg_edge_ptr backarc = scc->backarcs[j]; | |
695 | int length; | |
696 | int distance = backarc->distance; | |
697 | ddg_node_ptr src = backarc->dest; | |
698 | ddg_node_ptr dest = backarc->src; | |
699 | ||
700 | length = longest_simple_path (g, src->cuid, dest->cuid, scc->nodes); | |
701 | if (length < 0 ) | |
702 | { | |
703 | /* fprintf (stderr, "Backarc not on simple cycle in SCC.\n"); */ | |
704 | continue; | |
705 | } | |
706 | length += backarc->latency; | |
707 | result = MAX (result, (length / distance)); | |
708 | } | |
709 | scc->recurrence_length = result; | |
710 | } | |
711 | ||
712 | /* Create a new SCC given the set of its nodes. Compute its recurrence_length | |
713 | and mark edges that belong to this scc as IN_SCC. */ | |
714 | static ddg_scc_ptr | |
715 | create_scc (ddg_ptr g, sbitmap nodes) | |
716 | { | |
717 | ddg_scc_ptr scc; | |
dfea6c85 | 718 | unsigned int u = 0; |
b6e7e9af | 719 | sbitmap_iterator sbi; |
d397e8c6 MH |
720 | |
721 | scc = (ddg_scc_ptr) xmalloc (sizeof (struct ddg_scc)); | |
722 | scc->backarcs = NULL; | |
723 | scc->num_backarcs = 0; | |
724 | scc->nodes = sbitmap_alloc (g->num_nodes); | |
725 | sbitmap_copy (scc->nodes, nodes); | |
726 | ||
727 | /* Mark the backarcs that belong to this SCC. */ | |
b6e7e9af | 728 | EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, u, sbi) |
d397e8c6 MH |
729 | { |
730 | ddg_edge_ptr e; | |
731 | ddg_node_ptr n = &g->nodes[u]; | |
732 | ||
733 | for (e = n->out; e; e = e->next_out) | |
734 | if (TEST_BIT (nodes, e->dest->cuid)) | |
735 | { | |
736 | e->aux.count = IN_SCC; | |
737 | if (e->distance > 0) | |
738 | add_backarc_to_scc (scc, e); | |
739 | } | |
b6e7e9af | 740 | } |
d397e8c6 MH |
741 | |
742 | set_recurrence_length (scc, g); | |
743 | return scc; | |
744 | } | |
745 | ||
746 | /* Cleans the memory allocation of a given SCC. */ | |
747 | static void | |
748 | free_scc (ddg_scc_ptr scc) | |
749 | { | |
750 | if (!scc) | |
751 | return; | |
752 | ||
753 | sbitmap_free (scc->nodes); | |
754 | if (scc->num_backarcs > 0) | |
755 | free (scc->backarcs); | |
756 | free (scc); | |
757 | } | |
758 | ||
759 | ||
760 | /* Add a given edge known to be a backarc to the given DDG. */ | |
761 | static void | |
762 | add_backarc_to_ddg (ddg_ptr g, ddg_edge_ptr e) | |
763 | { | |
764 | int size = (g->num_backarcs + 1) * sizeof (ddg_edge_ptr); | |
765 | ||
766 | add_edge_to_ddg (g, e); | |
767 | g->backarcs = (ddg_edge_ptr *) xrealloc (g->backarcs, size); | |
768 | g->backarcs[g->num_backarcs++] = e; | |
769 | } | |
770 | ||
771 | /* Add backarc to an SCC. */ | |
772 | static void | |
773 | add_backarc_to_scc (ddg_scc_ptr scc, ddg_edge_ptr e) | |
774 | { | |
775 | int size = (scc->num_backarcs + 1) * sizeof (ddg_edge_ptr); | |
776 | ||
777 | scc->backarcs = (ddg_edge_ptr *) xrealloc (scc->backarcs, size); | |
778 | scc->backarcs[scc->num_backarcs++] = e; | |
779 | } | |
780 | ||
781 | /* Add the given SCC to the DDG. */ | |
782 | static void | |
783 | add_scc_to_ddg (ddg_all_sccs_ptr g, ddg_scc_ptr scc) | |
784 | { | |
785 | int size = (g->num_sccs + 1) * sizeof (ddg_scc_ptr); | |
786 | ||
787 | g->sccs = (ddg_scc_ptr *) xrealloc (g->sccs, size); | |
788 | g->sccs[g->num_sccs++] = scc; | |
789 | } | |
790 | ||
791 | /* Given the instruction INSN return the node that represents it. */ | |
792 | ddg_node_ptr | |
793 | get_node_of_insn (ddg_ptr g, rtx insn) | |
794 | { | |
795 | int i; | |
796 | ||
797 | for (i = 0; i < g->num_nodes; i++) | |
798 | if (insn == g->nodes[i].insn) | |
799 | return &g->nodes[i]; | |
800 | return NULL; | |
801 | } | |
802 | ||
803 | /* Given a set OPS of nodes in the DDG, find the set of their successors | |
804 | which are not in OPS, and set their bits in SUCC. Bits corresponding to | |
805 | OPS are cleared from SUCC. Leaves the other bits in SUCC unchanged. */ | |
806 | void | |
807 | find_successors (sbitmap succ, ddg_ptr g, sbitmap ops) | |
808 | { | |
dfea6c85 | 809 | unsigned int i = 0; |
b6e7e9af | 810 | sbitmap_iterator sbi; |
d397e8c6 | 811 | |
b6e7e9af | 812 | EXECUTE_IF_SET_IN_SBITMAP (ops, 0, i, sbi) |
d397e8c6 MH |
813 | { |
814 | const sbitmap node_succ = NODE_SUCCESSORS (&g->nodes[i]); | |
815 | sbitmap_a_or_b (succ, succ, node_succ); | |
b6e7e9af | 816 | }; |
d397e8c6 MH |
817 | |
818 | /* We want those that are not in ops. */ | |
819 | sbitmap_difference (succ, succ, ops); | |
820 | } | |
821 | ||
822 | /* Given a set OPS of nodes in the DDG, find the set of their predecessors | |
823 | which are not in OPS, and set their bits in PREDS. Bits corresponding to | |
824 | OPS are cleared from PREDS. Leaves the other bits in PREDS unchanged. */ | |
825 | void | |
826 | find_predecessors (sbitmap preds, ddg_ptr g, sbitmap ops) | |
827 | { | |
dfea6c85 | 828 | unsigned int i = 0; |
b6e7e9af | 829 | sbitmap_iterator sbi; |
d397e8c6 | 830 | |
b6e7e9af | 831 | EXECUTE_IF_SET_IN_SBITMAP (ops, 0, i, sbi) |
d397e8c6 MH |
832 | { |
833 | const sbitmap node_preds = NODE_PREDECESSORS (&g->nodes[i]); | |
834 | sbitmap_a_or_b (preds, preds, node_preds); | |
b6e7e9af | 835 | }; |
d397e8c6 MH |
836 | |
837 | /* We want those that are not in ops. */ | |
838 | sbitmap_difference (preds, preds, ops); | |
839 | } | |
840 | ||
841 | ||
842 | /* Compare function to be passed to qsort to order the backarcs in descending | |
843 | recMII order. */ | |
844 | static int | |
845 | compare_sccs (const void *s1, const void *s2) | |
846 | { | |
5f754896 KG |
847 | const int rec_l1 = (*(const ddg_scc_ptr *)s1)->recurrence_length; |
848 | const int rec_l2 = (*(const ddg_scc_ptr *)s2)->recurrence_length; | |
d397e8c6 MH |
849 | return ((rec_l2 > rec_l1) - (rec_l2 < rec_l1)); |
850 | ||
851 | } | |
852 | ||
853 | /* Order the backarcs in descending recMII order using compare_sccs. */ | |
854 | static void | |
855 | order_sccs (ddg_all_sccs_ptr g) | |
856 | { | |
857 | qsort (g->sccs, g->num_sccs, sizeof (ddg_scc_ptr), | |
858 | (int (*) (const void *, const void *)) compare_sccs); | |
859 | } | |
860 | ||
72b31363 | 861 | #ifdef ENABLE_CHECKING |
8cec1624 RE |
862 | /* Check that every node in SCCS belongs to exactly one strongly connected |
863 | component and that no element of SCCS is empty. */ | |
864 | static void | |
865 | check_sccs (ddg_all_sccs_ptr sccs, int num_nodes) | |
866 | { | |
867 | int i = 0; | |
868 | sbitmap tmp = sbitmap_alloc (num_nodes); | |
869 | ||
870 | sbitmap_zero (tmp); | |
871 | for (i = 0; i < sccs->num_sccs; i++) | |
872 | { | |
873 | gcc_assert (!sbitmap_empty_p (sccs->sccs[i]->nodes)); | |
874 | /* Verify that every node in sccs is in exactly one strongly | |
875 | connected component. */ | |
876 | gcc_assert (!sbitmap_any_common_bits (tmp, sccs->sccs[i]->nodes)); | |
877 | sbitmap_a_or_b (tmp, tmp, sccs->sccs[i]->nodes); | |
878 | } | |
879 | sbitmap_free (tmp); | |
880 | } | |
72b31363 | 881 | #endif |
8cec1624 | 882 | |
d397e8c6 MH |
883 | /* Perform the Strongly Connected Components decomposing algorithm on the |
884 | DDG and return DDG_ALL_SCCS structure that contains them. */ | |
885 | ddg_all_sccs_ptr | |
886 | create_ddg_all_sccs (ddg_ptr g) | |
887 | { | |
888 | int i; | |
889 | int num_nodes = g->num_nodes; | |
890 | sbitmap from = sbitmap_alloc (num_nodes); | |
891 | sbitmap to = sbitmap_alloc (num_nodes); | |
892 | sbitmap scc_nodes = sbitmap_alloc (num_nodes); | |
893 | ddg_all_sccs_ptr sccs = (ddg_all_sccs_ptr) | |
894 | xmalloc (sizeof (struct ddg_all_sccs)); | |
895 | ||
896 | sccs->ddg = g; | |
897 | sccs->sccs = NULL; | |
898 | sccs->num_sccs = 0; | |
899 | ||
900 | for (i = 0; i < g->num_backarcs; i++) | |
901 | { | |
902 | ddg_scc_ptr scc; | |
903 | ddg_edge_ptr backarc = g->backarcs[i]; | |
904 | ddg_node_ptr src = backarc->src; | |
905 | ddg_node_ptr dest = backarc->dest; | |
906 | ||
907 | /* If the backarc already belongs to an SCC, continue. */ | |
908 | if (backarc->aux.count == IN_SCC) | |
909 | continue; | |
910 | ||
7ee1ad84 | 911 | sbitmap_zero (scc_nodes); |
d397e8c6 MH |
912 | sbitmap_zero (from); |
913 | sbitmap_zero (to); | |
914 | SET_BIT (from, dest->cuid); | |
915 | SET_BIT (to, src->cuid); | |
916 | ||
917 | if (find_nodes_on_paths (scc_nodes, g, from, to)) | |
918 | { | |
919 | scc = create_scc (g, scc_nodes); | |
920 | add_scc_to_ddg (sccs, scc); | |
921 | } | |
922 | } | |
923 | order_sccs (sccs); | |
924 | sbitmap_free (from); | |
925 | sbitmap_free (to); | |
926 | sbitmap_free (scc_nodes); | |
8cec1624 RE |
927 | #ifdef ENABLE_CHECKING |
928 | check_sccs (sccs, num_nodes); | |
929 | #endif | |
d397e8c6 MH |
930 | return sccs; |
931 | } | |
932 | ||
933 | /* Frees the memory allocated for all SCCs of the DDG, but keeps the DDG. */ | |
934 | void | |
935 | free_ddg_all_sccs (ddg_all_sccs_ptr all_sccs) | |
936 | { | |
937 | int i; | |
938 | ||
939 | if (!all_sccs) | |
940 | return; | |
941 | ||
942 | for (i = 0; i < all_sccs->num_sccs; i++) | |
943 | free_scc (all_sccs->sccs[i]); | |
944 | ||
945 | free (all_sccs); | |
946 | } | |
947 | ||
948 | \f | |
949 | /* Given FROM - a bitmap of source nodes - and TO - a bitmap of destination | |
950 | nodes - find all nodes that lie on paths from FROM to TO (not excluding | |
b01d837f | 951 | nodes from FROM and TO). Return nonzero if nodes exist. */ |
d397e8c6 MH |
952 | int |
953 | find_nodes_on_paths (sbitmap result, ddg_ptr g, sbitmap from, sbitmap to) | |
954 | { | |
955 | int answer; | |
b6e7e9af | 956 | int change; |
dfea6c85 | 957 | unsigned int u = 0; |
d397e8c6 | 958 | int num_nodes = g->num_nodes; |
b6e7e9af KH |
959 | sbitmap_iterator sbi; |
960 | ||
d397e8c6 MH |
961 | sbitmap workset = sbitmap_alloc (num_nodes); |
962 | sbitmap reachable_from = sbitmap_alloc (num_nodes); | |
963 | sbitmap reach_to = sbitmap_alloc (num_nodes); | |
964 | sbitmap tmp = sbitmap_alloc (num_nodes); | |
965 | ||
966 | sbitmap_copy (reachable_from, from); | |
967 | sbitmap_copy (tmp, from); | |
968 | ||
969 | change = 1; | |
970 | while (change) | |
971 | { | |
972 | change = 0; | |
973 | sbitmap_copy (workset, tmp); | |
974 | sbitmap_zero (tmp); | |
b6e7e9af | 975 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, sbi) |
d397e8c6 MH |
976 | { |
977 | ddg_edge_ptr e; | |
978 | ddg_node_ptr u_node = &g->nodes[u]; | |
979 | ||
980 | for (e = u_node->out; e != (ddg_edge_ptr) 0; e = e->next_out) | |
981 | { | |
982 | ddg_node_ptr v_node = e->dest; | |
983 | int v = v_node->cuid; | |
984 | ||
985 | if (!TEST_BIT (reachable_from, v)) | |
986 | { | |
987 | SET_BIT (reachable_from, v); | |
988 | SET_BIT (tmp, v); | |
989 | change = 1; | |
990 | } | |
991 | } | |
b6e7e9af | 992 | } |
d397e8c6 MH |
993 | } |
994 | ||
995 | sbitmap_copy (reach_to, to); | |
996 | sbitmap_copy (tmp, to); | |
997 | ||
998 | change = 1; | |
999 | while (change) | |
1000 | { | |
1001 | change = 0; | |
1002 | sbitmap_copy (workset, tmp); | |
1003 | sbitmap_zero (tmp); | |
b6e7e9af | 1004 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, sbi) |
d397e8c6 MH |
1005 | { |
1006 | ddg_edge_ptr e; | |
1007 | ddg_node_ptr u_node = &g->nodes[u]; | |
1008 | ||
1009 | for (e = u_node->in; e != (ddg_edge_ptr) 0; e = e->next_in) | |
1010 | { | |
1011 | ddg_node_ptr v_node = e->src; | |
1012 | int v = v_node->cuid; | |
1013 | ||
1014 | if (!TEST_BIT (reach_to, v)) | |
1015 | { | |
1016 | SET_BIT (reach_to, v); | |
1017 | SET_BIT (tmp, v); | |
1018 | change = 1; | |
1019 | } | |
1020 | } | |
b6e7e9af | 1021 | } |
d397e8c6 MH |
1022 | } |
1023 | ||
1024 | answer = sbitmap_a_and_b_cg (result, reachable_from, reach_to); | |
1025 | sbitmap_free (workset); | |
1026 | sbitmap_free (reachable_from); | |
1027 | sbitmap_free (reach_to); | |
1028 | sbitmap_free (tmp); | |
1029 | return answer; | |
1030 | } | |
1031 | ||
1032 | ||
1033 | /* Updates the counts of U_NODE's successors (that belong to NODES) to be | |
1034 | at-least as large as the count of U_NODE plus the latency between them. | |
1035 | Sets a bit in TMP for each successor whose count was changed (increased). | |
1ea7e6ad | 1036 | Returns nonzero if any count was changed. */ |
d397e8c6 MH |
1037 | static int |
1038 | update_dist_to_successors (ddg_node_ptr u_node, sbitmap nodes, sbitmap tmp) | |
1039 | { | |
1040 | ddg_edge_ptr e; | |
1041 | int result = 0; | |
1042 | ||
1043 | for (e = u_node->out; e; e = e->next_out) | |
1044 | { | |
1045 | ddg_node_ptr v_node = e->dest; | |
1046 | int v = v_node->cuid; | |
1047 | ||
1048 | if (TEST_BIT (nodes, v) | |
1049 | && (e->distance == 0) | |
1050 | && (v_node->aux.count < u_node->aux.count + e->latency)) | |
1051 | { | |
1052 | v_node->aux.count = u_node->aux.count + e->latency; | |
1053 | SET_BIT (tmp, v); | |
1054 | result = 1; | |
1055 | } | |
1056 | } | |
1057 | return result; | |
1058 | } | |
1059 | ||
1060 | ||
1061 | /* Find the length of a longest path from SRC to DEST in G, | |
1062 | going only through NODES, and disregarding backarcs. */ | |
1063 | int | |
1064 | longest_simple_path (struct ddg * g, int src, int dest, sbitmap nodes) | |
1065 | { | |
b6e7e9af | 1066 | int i; |
dfea6c85 | 1067 | unsigned int u = 0; |
d397e8c6 MH |
1068 | int change = 1; |
1069 | int result; | |
1070 | int num_nodes = g->num_nodes; | |
1071 | sbitmap workset = sbitmap_alloc (num_nodes); | |
1072 | sbitmap tmp = sbitmap_alloc (num_nodes); | |
1073 | ||
1074 | ||
1075 | /* Data will hold the distance of the longest path found so far from | |
1076 | src to each node. Initialize to -1 = less than minimum. */ | |
1077 | for (i = 0; i < g->num_nodes; i++) | |
1078 | g->nodes[i].aux.count = -1; | |
1079 | g->nodes[src].aux.count = 0; | |
1080 | ||
1081 | sbitmap_zero (tmp); | |
1082 | SET_BIT (tmp, src); | |
1083 | ||
1084 | while (change) | |
1085 | { | |
b6e7e9af KH |
1086 | sbitmap_iterator sbi; |
1087 | ||
d397e8c6 MH |
1088 | change = 0; |
1089 | sbitmap_copy (workset, tmp); | |
1090 | sbitmap_zero (tmp); | |
b6e7e9af | 1091 | EXECUTE_IF_SET_IN_SBITMAP (workset, 0, u, sbi) |
d397e8c6 MH |
1092 | { |
1093 | ddg_node_ptr u_node = &g->nodes[u]; | |
1094 | ||
1095 | change |= update_dist_to_successors (u_node, nodes, tmp); | |
b6e7e9af | 1096 | } |
d397e8c6 MH |
1097 | } |
1098 | result = g->nodes[dest].aux.count; | |
1099 | sbitmap_free (workset); | |
1100 | sbitmap_free (tmp); | |
1101 | return result; | |
1102 | } |