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4ee9c684 | 1 | /* Rewrite a program in Normal form into SSA. |
841424cc | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011 |
8c4c00c1 | 3 | Free Software Foundation, Inc. |
4ee9c684 | 4 | Contributed by Diego Novillo <dnovillo@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 10 | the Free Software Foundation; either version 3, or (at your option) |
4ee9c684 | 11 | any later version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
4ee9c684 | 28 | #include "tm_p.h" |
29 | #include "langhooks.h" | |
4ee9c684 | 30 | #include "basic-block.h" |
4ee9c684 | 31 | #include "function.h" |
ce084dfc | 32 | #include "tree-pretty-print.h" |
33 | #include "gimple-pretty-print.h" | |
4ee9c684 | 34 | #include "bitmap.h" |
35 | #include "tree-flow.h" | |
75a70cf9 | 36 | #include "gimple.h" |
4ee9c684 | 37 | #include "tree-inline.h" |
4ee9c684 | 38 | #include "timevar.h" |
4ee9c684 | 39 | #include "hashtab.h" |
40 | #include "tree-dump.h" | |
41 | #include "tree-pass.h" | |
42 | #include "cfgloop.h" | |
43 | #include "domwalk.h" | |
095dcfa3 | 44 | #include "params.h" |
05f3df98 | 45 | #include "vecprim.h" |
4ee9c684 | 46 | |
75a70cf9 | 47 | |
4ee9c684 | 48 | /* This file builds the SSA form for a function as described in: |
49 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
50 | Computing Static Single Assignment Form and the Control Dependence | |
51 | Graph. ACM Transactions on Programming Languages and Systems, | |
52 | 13(4):451-490, October 1991. */ | |
53 | ||
4ee9c684 | 54 | /* Structure to map a variable VAR to the set of blocks that contain |
55 | definitions for VAR. */ | |
56 | struct def_blocks_d | |
57 | { | |
58 | /* The variable. */ | |
59 | tree var; | |
60 | ||
61 | /* Blocks that contain definitions of VAR. Bit I will be set if the | |
62 | Ith block contains a definition of VAR. */ | |
63 | bitmap def_blocks; | |
64 | ||
e551bd1a | 65 | /* Blocks that contain a PHI node for VAR. */ |
f3d9a16c | 66 | bitmap phi_blocks; |
67 | ||
4ee9c684 | 68 | /* Blocks where VAR is live-on-entry. Similar semantics as |
69 | DEF_BLOCKS. */ | |
70 | bitmap livein_blocks; | |
71 | }; | |
72 | ||
e551bd1a | 73 | |
4ee9c684 | 74 | /* Each entry in DEF_BLOCKS contains an element of type STRUCT |
75 | DEF_BLOCKS_D, mapping a variable VAR to a bitmap describing all the | |
76 | basic blocks where VAR is defined (assigned a new value). It also | |
77 | contains a bitmap of all the blocks where VAR is live-on-entry | |
78 | (i.e., there is a use of VAR in block B without a preceding | |
79 | definition in B). The live-on-entry information is used when | |
80 | computing PHI pruning heuristics. */ | |
81 | static htab_t def_blocks; | |
82 | ||
dd2d357d | 83 | /* Stack of trees used to restore the global currdefs to its original |
88dbf20f | 84 | state after completing rewriting of a block and its dominator |
85 | children. Its elements have the following properties: | |
dd2d357d | 86 | |
4fb5e5ca | 87 | - An SSA_NAME (N) indicates that the current definition of the |
88 | underlying variable should be set to the given SSA_NAME. If the | |
89 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
90 | next slot in the stack must be a _DECL node (SYM). In this case, | |
91 | the name N in the previous slot is the current reaching | |
92 | definition for SYM. | |
dd2d357d | 93 | |
88dbf20f | 94 | - A _DECL node indicates that the underlying variable has no |
95 | current definition. | |
e551bd1a | 96 | |
4fb5e5ca | 97 | - A NULL node at the top entry is used to mark the last slot |
88dbf20f | 98 | associated with the current block. */ |
046bfc77 | 99 | static VEC(tree,heap) *block_defs_stack; |
486b57c7 | 100 | |
75a70cf9 | 101 | |
88dbf20f | 102 | /* Set of existing SSA names being replaced by update_ssa. */ |
103 | static sbitmap old_ssa_names; | |
104 | ||
105 | /* Set of new SSA names being added by update_ssa. Note that both | |
106 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
107 | the operations done on them are presence tests. */ | |
108 | static sbitmap new_ssa_names; | |
109 | ||
6bf320fb | 110 | sbitmap interesting_blocks; |
75a70cf9 | 111 | |
88dbf20f | 112 | /* Set of SSA names that have been marked to be released after they |
113 | were registered in the replacement table. They will be finally | |
114 | released after we finish updating the SSA web. */ | |
115 | static bitmap names_to_release; | |
116 | ||
75a70cf9 | 117 | static VEC(gimple_vec, heap) *phis_to_rewrite; |
70630fcd | 118 | |
119 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
70630fcd | 120 | static bitmap blocks_with_phis_to_rewrite; |
121 | ||
88dbf20f | 122 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
123 | to grow as the callers to register_new_name_mapping will typically | |
124 | create new names on the fly. FIXME. Currently set to 1/3 to avoid | |
125 | frequent reallocations but still need to find a reasonable growth | |
126 | strategy. */ | |
127 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) | |
128 | ||
129 | /* Tuple used to represent replacement mappings. */ | |
130 | struct repl_map_d | |
131 | { | |
132 | tree name; | |
133 | bitmap set; | |
134 | }; | |
135 | ||
75a70cf9 | 136 | |
88dbf20f | 137 | /* NEW -> OLD_SET replacement table. If we are replacing several |
138 | existing SSA names O_1, O_2, ..., O_j with a new name N_i, | |
139 | then REPL_TBL[N_i] = { O_1, O_2, ..., O_j }. */ | |
140 | static htab_t repl_tbl; | |
141 | ||
dd277d48 | 142 | /* The function the SSA updating data structures have been initialized for. |
143 | NULL if they need to be initialized by register_new_name_mapping. */ | |
144 | static struct function *update_ssa_initialized_fn = NULL; | |
88dbf20f | 145 | |
095dcfa3 | 146 | /* Statistics kept by update_ssa to use in the virtual mapping |
147 | heuristic. If the number of virtual mappings is beyond certain | |
148 | threshold, the updater will switch from using the mappings into | |
149 | renaming the virtual symbols from scratch. In some cases, the | |
150 | large number of name mappings for virtual names causes significant | |
151 | slowdowns in the PHI insertion code. */ | |
152 | struct update_ssa_stats_d | |
153 | { | |
154 | unsigned num_virtual_mappings; | |
155 | unsigned num_total_mappings; | |
156 | bitmap virtual_symbols; | |
157 | unsigned num_virtual_symbols; | |
158 | }; | |
159 | static struct update_ssa_stats_d update_ssa_stats; | |
88dbf20f | 160 | |
4ee9c684 | 161 | /* Global data to attach to the main dominator walk structure. */ |
162 | struct mark_def_sites_global_data | |
163 | { | |
88dbf20f | 164 | /* This bitmap contains the variables which are set before they |
165 | are used in a basic block. */ | |
ecddc799 | 166 | bitmap kills; |
4ee9c684 | 167 | }; |
168 | ||
f3d9a16c | 169 | |
88dbf20f | 170 | /* Information stored for SSA names. */ |
f3d9a16c | 171 | struct ssa_name_info |
172 | { | |
4fb5e5ca | 173 | /* The current reaching definition replacing this SSA name. */ |
2920559d | 174 | tree current_def; |
175 | ||
f3d9a16c | 176 | /* This field indicates whether or not the variable may need PHI nodes. |
177 | See the enum's definition for more detailed information about the | |
178 | states. */ | |
179 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
180 | ||
2920559d | 181 | /* Age of this record (so that info_for_ssa_name table can be cleared |
f0b5f617 | 182 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields |
2920559d | 183 | are assumed to be null. */ |
184 | unsigned age; | |
f3d9a16c | 185 | }; |
4ee9c684 | 186 | |
2920559d | 187 | /* The information associated with names. */ |
188 | typedef struct ssa_name_info *ssa_name_info_p; | |
189 | DEF_VEC_P (ssa_name_info_p); | |
190 | DEF_VEC_ALLOC_P (ssa_name_info_p, heap); | |
191 | ||
192 | static VEC(ssa_name_info_p, heap) *info_for_ssa_name; | |
193 | static unsigned current_info_for_ssa_name_age; | |
194 | ||
195 | /* The set of blocks affected by update_ssa. */ | |
2920559d | 196 | static bitmap blocks_to_update; |
4ee9c684 | 197 | |
88dbf20f | 198 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
199 | called several times to do different, but related, tasks. | |
200 | Initially, we need it to rename the whole program into SSA form. | |
201 | At other times, we may need it to only rename into SSA newly | |
202 | exposed symbols. Finally, we can also call it to incrementally fix | |
203 | an already built SSA web. */ | |
204 | enum rewrite_mode { | |
205 | /* Convert the whole function into SSA form. */ | |
206 | REWRITE_ALL, | |
207 | ||
208 | /* Incrementally update the SSA web by replacing existing SSA | |
209 | names with new ones. See update_ssa for details. */ | |
210 | REWRITE_UPDATE | |
211 | }; | |
212 | ||
213 | ||
88dbf20f | 214 | |
6cf80e5b | 215 | |
095dcfa3 | 216 | /* Prototypes for debugging functions. */ |
217 | extern void dump_tree_ssa (FILE *); | |
218 | extern void debug_tree_ssa (void); | |
219 | extern void debug_def_blocks (void); | |
220 | extern void dump_tree_ssa_stats (FILE *); | |
221 | extern void debug_tree_ssa_stats (void); | |
4fb5e5ca | 222 | extern void dump_update_ssa (FILE *); |
223 | extern void debug_update_ssa (void); | |
224 | extern void dump_names_replaced_by (FILE *, tree); | |
225 | extern void debug_names_replaced_by (tree); | |
226 | extern void dump_def_blocks (FILE *); | |
227 | extern void debug_def_blocks (void); | |
228 | extern void dump_defs_stack (FILE *, int); | |
229 | extern void debug_defs_stack (int); | |
230 | extern void dump_currdefs (FILE *); | |
231 | extern void debug_currdefs (void); | |
095dcfa3 | 232 | |
75a70cf9 | 233 | /* Return true if STMT needs to be rewritten. When renaming a subset |
234 | of the variables, not all statements will be processed. This is | |
235 | decided in mark_def_sites. */ | |
236 | ||
237 | static inline bool | |
238 | rewrite_uses_p (gimple stmt) | |
239 | { | |
240 | return gimple_visited_p (stmt); | |
241 | } | |
242 | ||
243 | ||
244 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
245 | ||
246 | static inline void | |
247 | set_rewrite_uses (gimple stmt, bool rewrite_p) | |
248 | { | |
249 | gimple_set_visited (stmt, rewrite_p); | |
250 | } | |
251 | ||
252 | ||
253 | /* Return true if the DEFs created by statement STMT should be | |
254 | registered when marking new definition sites. This is slightly | |
255 | different than rewrite_uses_p: it's used by update_ssa to | |
256 | distinguish statements that need to have both uses and defs | |
257 | processed from those that only need to have their defs processed. | |
258 | Statements that define new SSA names only need to have their defs | |
259 | registered, but they don't need to have their uses renamed. */ | |
260 | ||
261 | static inline bool | |
262 | register_defs_p (gimple stmt) | |
263 | { | |
264 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
265 | } | |
266 | ||
267 | ||
268 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
269 | ||
270 | static inline void | |
271 | set_register_defs (gimple stmt, bool register_defs_p) | |
272 | { | |
273 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
274 | } | |
275 | ||
276 | ||
f3d9a16c | 277 | /* Get the information associated with NAME. */ |
278 | ||
4fb5e5ca | 279 | static inline ssa_name_info_p |
f3d9a16c | 280 | get_ssa_name_ann (tree name) |
281 | { | |
2920559d | 282 | unsigned ver = SSA_NAME_VERSION (name); |
283 | unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name); | |
284 | struct ssa_name_info *info; | |
285 | ||
286 | if (ver >= len) | |
287 | { | |
288 | unsigned new_len = num_ssa_names; | |
289 | ||
290 | VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name, new_len); | |
291 | while (len++ < new_len) | |
292 | { | |
293 | struct ssa_name_info *info = XCNEW (struct ssa_name_info); | |
294 | info->age = current_info_for_ssa_name_age; | |
295 | VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info); | |
296 | } | |
297 | } | |
298 | ||
299 | info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver); | |
300 | if (info->age < current_info_for_ssa_name_age) | |
301 | { | |
8458f4ca | 302 | info->need_phi_state = NEED_PHI_STATE_UNKNOWN; |
2920559d | 303 | info->current_def = NULL_TREE; |
304 | info->age = current_info_for_ssa_name_age; | |
305 | } | |
f3d9a16c | 306 | |
2920559d | 307 | return info; |
f3d9a16c | 308 | } |
309 | ||
4fb5e5ca | 310 | |
311 | /* Clears info for SSA names. */ | |
2920559d | 312 | |
313 | static void | |
314 | clear_ssa_name_info (void) | |
315 | { | |
316 | current_info_for_ssa_name_age++; | |
317 | } | |
e551bd1a | 318 | |
4fb5e5ca | 319 | |
320 | /* Get phi_state field for VAR. */ | |
f3d9a16c | 321 | |
322 | static inline enum need_phi_state | |
323 | get_phi_state (tree var) | |
324 | { | |
325 | if (TREE_CODE (var) == SSA_NAME) | |
326 | return get_ssa_name_ann (var)->need_phi_state; | |
327 | else | |
328 | return var_ann (var)->need_phi_state; | |
329 | } | |
330 | ||
e551bd1a | 331 | |
f3d9a16c | 332 | /* Sets phi_state field for VAR to STATE. */ |
333 | ||
334 | static inline void | |
335 | set_phi_state (tree var, enum need_phi_state state) | |
336 | { | |
337 | if (TREE_CODE (var) == SSA_NAME) | |
338 | get_ssa_name_ann (var)->need_phi_state = state; | |
339 | else | |
340 | var_ann (var)->need_phi_state = state; | |
341 | } | |
342 | ||
e551bd1a | 343 | |
f3d9a16c | 344 | /* Return the current definition for VAR. */ |
345 | ||
095dcfa3 | 346 | tree |
f3d9a16c | 347 | get_current_def (tree var) |
348 | { | |
349 | if (TREE_CODE (var) == SSA_NAME) | |
350 | return get_ssa_name_ann (var)->current_def; | |
351 | else | |
352 | return var_ann (var)->current_def; | |
353 | } | |
354 | ||
e551bd1a | 355 | |
f3d9a16c | 356 | /* Sets current definition of VAR to DEF. */ |
357 | ||
095dcfa3 | 358 | void |
f3d9a16c | 359 | set_current_def (tree var, tree def) |
360 | { | |
361 | if (TREE_CODE (var) == SSA_NAME) | |
362 | get_ssa_name_ann (var)->current_def = def; | |
363 | else | |
364 | var_ann (var)->current_def = def; | |
365 | } | |
366 | ||
e551bd1a | 367 | |
f0b5f617 | 368 | /* Compute global livein information given the set of blocks where |
4ee9c684 | 369 | an object is locally live at the start of the block (LIVEIN) |
370 | and the set of blocks where the object is defined (DEF_BLOCKS). | |
371 | ||
372 | Note: This routine augments the existing local livein information | |
373 | to include global livein (i.e., it modifies the underlying bitmap | |
374 | for LIVEIN). */ | |
375 | ||
f3d9a16c | 376 | void |
75a70cf9 | 377 | compute_global_livein (bitmap livein ATTRIBUTE_UNUSED, bitmap def_blocks ATTRIBUTE_UNUSED) |
4ee9c684 | 378 | { |
379 | basic_block bb, *worklist, *tos; | |
4f917ffe | 380 | unsigned i; |
0cc4271a | 381 | bitmap_iterator bi; |
4ee9c684 | 382 | |
383 | tos = worklist | |
88dbf20f | 384 | = (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1)); |
4ee9c684 | 385 | |
0cc4271a | 386 | EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi) |
4fb5e5ca | 387 | *tos++ = BASIC_BLOCK (i); |
4ee9c684 | 388 | |
389 | /* Iterate until the worklist is empty. */ | |
390 | while (tos != worklist) | |
391 | { | |
392 | edge e; | |
cd665a06 | 393 | edge_iterator ei; |
4ee9c684 | 394 | |
395 | /* Pull a block off the worklist. */ | |
396 | bb = *--tos; | |
397 | ||
398 | /* For each predecessor block. */ | |
cd665a06 | 399 | FOR_EACH_EDGE (e, ei, bb->preds) |
4ee9c684 | 400 | { |
401 | basic_block pred = e->src; | |
402 | int pred_index = pred->index; | |
403 | ||
404 | /* None of this is necessary for the entry block. */ | |
405 | if (pred != ENTRY_BLOCK_PTR | |
406 | && ! bitmap_bit_p (livein, pred_index) | |
407 | && ! bitmap_bit_p (def_blocks, pred_index)) | |
408 | { | |
409 | *tos++ = pred; | |
410 | bitmap_set_bit (livein, pred_index); | |
411 | } | |
412 | } | |
413 | } | |
414 | ||
415 | free (worklist); | |
416 | } | |
417 | ||
418 | ||
2920559d | 419 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
420 | all statements in basic block BB. */ | |
421 | ||
422 | static void | |
423 | initialize_flags_in_bb (basic_block bb) | |
424 | { | |
75a70cf9 | 425 | gimple stmt; |
426 | gimple_stmt_iterator gsi; | |
2920559d | 427 | |
75a70cf9 | 428 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 429 | { |
75a70cf9 | 430 | gimple phi = gsi_stmt (gsi); |
431 | set_rewrite_uses (phi, false); | |
432 | set_register_defs (phi, false); | |
2920559d | 433 | } |
434 | ||
75a70cf9 | 435 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 436 | { |
75a70cf9 | 437 | stmt = gsi_stmt (gsi); |
438 | ||
2920559d | 439 | /* We are going to use the operand cache API, such as |
440 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
441 | cache for each statement should be up-to-date. */ | |
75a70cf9 | 442 | gcc_assert (!gimple_modified_p (stmt)); |
443 | set_rewrite_uses (stmt, false); | |
444 | set_register_defs (stmt, false); | |
2920559d | 445 | } |
446 | } | |
447 | ||
448 | /* Mark block BB as interesting for update_ssa. */ | |
449 | ||
450 | static void | |
451 | mark_block_for_update (basic_block bb) | |
452 | { | |
453 | gcc_assert (blocks_to_update != NULL); | |
39192870 | 454 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
2920559d | 455 | return; |
2920559d | 456 | initialize_flags_in_bb (bb); |
457 | } | |
458 | ||
e551bd1a | 459 | /* Return the set of blocks where variable VAR is defined and the blocks |
460 | where VAR is live on entry (livein). If no entry is found in | |
461 | DEF_BLOCKS, a new one is created and returned. */ | |
4ee9c684 | 462 | |
e551bd1a | 463 | static inline struct def_blocks_d * |
464 | get_def_blocks_for (tree var) | |
4ee9c684 | 465 | { |
e551bd1a | 466 | struct def_blocks_d db, *db_p; |
467 | void **slot; | |
4ee9c684 | 468 | |
e551bd1a | 469 | db.var = var; |
470 | slot = htab_find_slot (def_blocks, (void *) &db, INSERT); | |
471 | if (*slot == NULL) | |
4ee9c684 | 472 | { |
680a19b9 | 473 | db_p = XNEW (struct def_blocks_d); |
e551bd1a | 474 | db_p->var = var; |
475 | db_p->def_blocks = BITMAP_ALLOC (NULL); | |
476 | db_p->phi_blocks = BITMAP_ALLOC (NULL); | |
477 | db_p->livein_blocks = BITMAP_ALLOC (NULL); | |
478 | *slot = (void *) db_p; | |
2cf24776 | 479 | } |
e551bd1a | 480 | else |
481 | db_p = (struct def_blocks_d *) *slot; | |
2cf24776 | 482 | |
e551bd1a | 483 | return db_p; |
4ee9c684 | 484 | } |
485 | ||
6cf80e5b | 486 | |
f3d9a16c | 487 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
88dbf20f | 488 | VAR is defined by a PHI node. */ |
4ee9c684 | 489 | |
490 | static void | |
88dbf20f | 491 | set_def_block (tree var, basic_block bb, bool phi_p) |
4ee9c684 | 492 | { |
493 | struct def_blocks_d *db_p; | |
ce898113 | 494 | enum need_phi_state state; |
495 | ||
f3d9a16c | 496 | state = get_phi_state (var); |
4ee9c684 | 497 | db_p = get_def_blocks_for (var); |
498 | ||
499 | /* Set the bit corresponding to the block where VAR is defined. */ | |
500 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
f3d9a16c | 501 | if (phi_p) |
502 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
4ee9c684 | 503 | |
e551bd1a | 504 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 505 | |
506 | If we are in the UNKNOWN state, then this is the first definition | |
507 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
e551bd1a | 508 | we do not need a PHI node for this variable at this time (i.e., |
4ee9c684 | 509 | transition to NEED_PHI_STATE_NO). |
510 | ||
511 | If we are in any other state, then we either have multiple definitions | |
512 | of this variable occurring in different blocks or we saw a use of the | |
513 | variable which was not dominated by the block containing the | |
514 | definition(s). In this case we may need a PHI node, so enter | |
515 | state NEED_PHI_STATE_MAYBE. */ | |
516 | if (state == NEED_PHI_STATE_UNKNOWN) | |
f3d9a16c | 517 | set_phi_state (var, NEED_PHI_STATE_NO); |
4ee9c684 | 518 | else |
f3d9a16c | 519 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
4ee9c684 | 520 | } |
521 | ||
522 | ||
523 | /* Mark block BB as having VAR live at the entry to BB. */ | |
524 | ||
525 | static void | |
526 | set_livein_block (tree var, basic_block bb) | |
527 | { | |
528 | struct def_blocks_d *db_p; | |
f3d9a16c | 529 | enum need_phi_state state = get_phi_state (var); |
4ee9c684 | 530 | |
531 | db_p = get_def_blocks_for (var); | |
532 | ||
533 | /* Set the bit corresponding to the block where VAR is live in. */ | |
534 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
535 | ||
e551bd1a | 536 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 537 | |
538 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
539 | by the single block containing the definition(s) of this variable. If | |
540 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
541 | NEED_PHI_STATE_MAYBE. */ | |
542 | if (state == NEED_PHI_STATE_NO) | |
543 | { | |
544 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
545 | ||
546 | if (def_block_index == -1 | |
547 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
548 | BASIC_BLOCK (def_block_index))) | |
f3d9a16c | 549 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
4ee9c684 | 550 | } |
551 | else | |
f3d9a16c | 552 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
4ee9c684 | 553 | } |
554 | ||
555 | ||
88dbf20f | 556 | /* Return true if symbol SYM is marked for renaming. */ |
4ee9c684 | 557 | |
182cf5a9 | 558 | bool |
88dbf20f | 559 | symbol_marked_for_renaming (tree sym) |
4ee9c684 | 560 | { |
dd277d48 | 561 | return bitmap_bit_p (SYMS_TO_RENAME (cfun), DECL_UID (sym)); |
88dbf20f | 562 | } |
563 | ||
564 | ||
565 | /* Return true if NAME is in OLD_SSA_NAMES. */ | |
4ee9c684 | 566 | |
88dbf20f | 567 | static inline bool |
568 | is_old_name (tree name) | |
569 | { | |
095dcfa3 | 570 | unsigned ver = SSA_NAME_VERSION (name); |
dd277d48 | 571 | if (!new_ssa_names) |
572 | return false; | |
095dcfa3 | 573 | return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver); |
88dbf20f | 574 | } |
575 | ||
576 | ||
577 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
ce898113 | 578 | |
88dbf20f | 579 | static inline bool |
580 | is_new_name (tree name) | |
581 | { | |
095dcfa3 | 582 | unsigned ver = SSA_NAME_VERSION (name); |
dd277d48 | 583 | if (!new_ssa_names) |
584 | return false; | |
095dcfa3 | 585 | return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver); |
4ee9c684 | 586 | } |
587 | ||
e551bd1a | 588 | |
88dbf20f | 589 | /* Hashing and equality functions for REPL_TBL. */ |
56004dc5 | 590 | |
88dbf20f | 591 | static hashval_t |
592 | repl_map_hash (const void *p) | |
56004dc5 | 593 | { |
88dbf20f | 594 | return htab_hash_pointer ((const void *)((const struct repl_map_d *)p)->name); |
595 | } | |
56004dc5 | 596 | |
88dbf20f | 597 | static int |
598 | repl_map_eq (const void *p1, const void *p2) | |
599 | { | |
600 | return ((const struct repl_map_d *)p1)->name | |
601 | == ((const struct repl_map_d *)p2)->name; | |
602 | } | |
603 | ||
604 | static void | |
605 | repl_map_free (void *p) | |
606 | { | |
607 | BITMAP_FREE (((struct repl_map_d *)p)->set); | |
608 | free (p); | |
609 | } | |
610 | ||
611 | ||
f4e36c33 | 612 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
88dbf20f | 613 | |
614 | static inline bitmap | |
f4e36c33 | 615 | names_replaced_by (tree new_tree) |
88dbf20f | 616 | { |
617 | struct repl_map_d m; | |
618 | void **slot; | |
619 | ||
f4e36c33 | 620 | m.name = new_tree; |
88dbf20f | 621 | slot = htab_find_slot (repl_tbl, (void *) &m, NO_INSERT); |
622 | ||
623 | /* If N was not registered in the replacement table, return NULL. */ | |
624 | if (slot == NULL || *slot == NULL) | |
625 | return NULL; | |
626 | ||
627 | return ((struct repl_map_d *) *slot)->set; | |
628 | } | |
629 | ||
630 | ||
f4e36c33 | 631 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
88dbf20f | 632 | |
633 | static inline void | |
f4e36c33 | 634 | add_to_repl_tbl (tree new_tree, tree old) |
88dbf20f | 635 | { |
636 | struct repl_map_d m, *mp; | |
637 | void **slot; | |
638 | ||
f4e36c33 | 639 | m.name = new_tree; |
88dbf20f | 640 | slot = htab_find_slot (repl_tbl, (void *) &m, INSERT); |
641 | if (*slot == NULL) | |
642 | { | |
680a19b9 | 643 | mp = XNEW (struct repl_map_d); |
f4e36c33 | 644 | mp->name = new_tree; |
88dbf20f | 645 | mp->set = BITMAP_ALLOC (NULL); |
646 | *slot = (void *) mp; | |
647 | } | |
648 | else | |
649 | mp = (struct repl_map_d *) *slot; | |
650 | ||
651 | bitmap_set_bit (mp->set, SSA_NAME_VERSION (old)); | |
652 | } | |
653 | ||
654 | ||
f4e36c33 | 655 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
88dbf20f | 656 | represents the set of names O_1 ... O_j replaced by N_i. This is |
657 | used by update_ssa and its helpers to introduce new SSA names in an | |
658 | already formed SSA web. */ | |
659 | ||
660 | static void | |
f4e36c33 | 661 | add_new_name_mapping (tree new_tree, tree old) |
88dbf20f | 662 | { |
663 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
664 | ||
f4e36c33 | 665 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
666 | gcc_assert (new_tree != old && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
095dcfa3 | 667 | |
095dcfa3 | 668 | /* If this mapping is for virtual names, we will need to update |
4fb5e5ca | 669 | virtual operands. If this is a mapping for .MEM, then we gather |
670 | the symbols associated with each name. */ | |
f4e36c33 | 671 | if (!is_gimple_reg (new_tree)) |
88dbf20f | 672 | { |
673 | tree sym; | |
674 | ||
4fb5e5ca | 675 | update_ssa_stats.num_virtual_mappings++; |
676 | update_ssa_stats.num_virtual_symbols++; | |
677 | ||
095dcfa3 | 678 | /* Keep counts of virtual mappings and symbols to use in the |
679 | virtual mapping heuristic. If we have large numbers of | |
680 | virtual mappings for a relatively low number of symbols, it | |
681 | will make more sense to rename the symbols from scratch. | |
682 | Otherwise, the insertion of PHI nodes for each of the old | |
683 | names in these mappings will be very slow. */ | |
f4e36c33 | 684 | sym = SSA_NAME_VAR (new_tree); |
4fb5e5ca | 685 | bitmap_set_bit (update_ssa_stats.virtual_symbols, DECL_UID (sym)); |
686 | } | |
687 | ||
688 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our | |
689 | caller may have created new names since the set was created. */ | |
690 | if (new_ssa_names->n_bits <= num_ssa_names - 1) | |
691 | { | |
692 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
693 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
694 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
88dbf20f | 695 | } |
696 | ||
88dbf20f | 697 | /* Update the REPL_TBL table. */ |
f4e36c33 | 698 | add_to_repl_tbl (new_tree, old); |
56004dc5 | 699 | |
88dbf20f | 700 | /* If OLD had already been registered as a new name, then all the |
f4e36c33 | 701 | names that OLD replaces should also be replaced by NEW_TREE. */ |
88dbf20f | 702 | if (is_new_name (old)) |
f4e36c33 | 703 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
88dbf20f | 704 | |
f4e36c33 | 705 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
88dbf20f | 706 | respectively. */ |
f4e36c33 | 707 | SET_BIT (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
88dbf20f | 708 | SET_BIT (old_ssa_names, SSA_NAME_VERSION (old)); |
709 | ||
095dcfa3 | 710 | /* Update mapping counter to use in the virtual mapping heuristic. */ |
711 | update_ssa_stats.num_total_mappings++; | |
88dbf20f | 712 | |
713 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
56004dc5 | 714 | } |
4ee9c684 | 715 | |
4ee9c684 | 716 | |
e551bd1a | 717 | /* Call back for walk_dominator_tree used to collect definition sites |
718 | for every variable in the function. For every statement S in block | |
719 | BB: | |
4ee9c684 | 720 | |
b66731e8 | 721 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
6bf320fb | 722 | KILLS. |
4ee9c684 | 723 | |
e551bd1a | 724 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
5cdd0289 | 725 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
4ee9c684 | 726 | |
e551bd1a | 727 | This information is used to determine which variables are live |
728 | across block boundaries to reduce the number of PHI nodes | |
729 | we create. */ | |
4ee9c684 | 730 | |
e551bd1a | 731 | static void |
6bf320fb | 732 | mark_def_sites (basic_block bb, gimple stmt, bitmap kills) |
e551bd1a | 733 | { |
75a70cf9 | 734 | tree def; |
e551bd1a | 735 | use_operand_p use_p; |
e551bd1a | 736 | ssa_op_iter iter; |
737 | ||
75a70cf9 | 738 | /* Since this is the first time that we rewrite the program into SSA |
739 | form, force an operand scan on every statement. */ | |
75a70cf9 | 740 | update_stmt (stmt); |
e551bd1a | 741 | |
2920559d | 742 | gcc_assert (blocks_to_update == NULL); |
75a70cf9 | 743 | set_register_defs (stmt, false); |
744 | set_rewrite_uses (stmt, false); | |
e551bd1a | 745 | |
9845d120 | 746 | if (is_gimple_debug (stmt)) |
841424cc | 747 | { |
748 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
749 | { | |
750 | tree sym = USE_FROM_PTR (use_p); | |
751 | gcc_assert (DECL_P (sym)); | |
752 | set_rewrite_uses (stmt, true); | |
753 | } | |
754 | if (rewrite_uses_p (stmt)) | |
755 | SET_BIT (interesting_blocks, bb->index); | |
756 | return; | |
757 | } | |
9845d120 | 758 | |
e551bd1a | 759 | /* If a variable is used before being set, then the variable is live |
760 | across a block boundary, so mark it live-on-entry to BB. */ | |
4fb5e5ca | 761 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
e551bd1a | 762 | { |
88dbf20f | 763 | tree sym = USE_FROM_PTR (use_p); |
764 | gcc_assert (DECL_P (sym)); | |
a55dc2cd | 765 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
88dbf20f | 766 | set_livein_block (sym, bb); |
75a70cf9 | 767 | set_rewrite_uses (stmt, true); |
e551bd1a | 768 | } |
48e1416a | 769 | |
4fb5e5ca | 770 | /* Now process the defs. Mark BB as the definition block and add |
771 | each def to the set of killed symbols. */ | |
772 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) | |
e551bd1a | 773 | { |
88dbf20f | 774 | gcc_assert (DECL_P (def)); |
775 | set_def_block (def, bb, false); | |
a55dc2cd | 776 | bitmap_set_bit (kills, DECL_UID (def)); |
75a70cf9 | 777 | set_register_defs (stmt, true); |
e551bd1a | 778 | } |
88dbf20f | 779 | |
780 | /* If we found the statement interesting then also mark the block BB | |
781 | as interesting. */ | |
75a70cf9 | 782 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
6bf320fb | 783 | SET_BIT (interesting_blocks, bb->index); |
e551bd1a | 784 | } |
785 | ||
f50cf978 | 786 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
787 | in the dfs numbering of the dominance tree. */ | |
788 | ||
789 | struct dom_dfsnum | |
790 | { | |
791 | /* Basic block whose index this entry corresponds to. */ | |
792 | unsigned bb_index; | |
793 | ||
794 | /* The dfs number of this node. */ | |
795 | unsigned dfs_num; | |
796 | }; | |
797 | ||
798 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
799 | for qsort. */ | |
800 | ||
801 | static int | |
802 | cmp_dfsnum (const void *a, const void *b) | |
803 | { | |
45ba1503 | 804 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
805 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f50cf978 | 806 | |
807 | return (int) da->dfs_num - (int) db->dfs_num; | |
808 | } | |
809 | ||
810 | /* Among the intervals starting at the N points specified in DEFS, find | |
811 | the one that contains S, and return its bb_index. */ | |
812 | ||
813 | static unsigned | |
814 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
815 | { | |
816 | unsigned f = 0, t = n, m; | |
817 | ||
818 | while (t > f + 1) | |
819 | { | |
820 | m = (f + t) / 2; | |
821 | if (defs[m].dfs_num <= s) | |
822 | f = m; | |
823 | else | |
824 | t = m; | |
825 | } | |
826 | ||
827 | return defs[f].bb_index; | |
828 | } | |
829 | ||
830 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
831 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
832 | ||
833 | static void | |
834 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
835 | { | |
836 | VEC(int, heap) *worklist; | |
837 | bitmap_iterator bi; | |
838 | unsigned i, b, p, u, top; | |
839 | bitmap live_phis; | |
840 | basic_block def_bb, use_bb; | |
841 | edge e; | |
842 | edge_iterator ei; | |
843 | bitmap to_remove; | |
844 | struct dom_dfsnum *defs; | |
845 | unsigned n_defs, adef; | |
846 | ||
847 | if (bitmap_empty_p (uses)) | |
848 | { | |
849 | bitmap_clear (phis); | |
850 | return; | |
851 | } | |
852 | ||
853 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
854 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
855 | to_remove = BITMAP_ALLOC (NULL); | |
856 | bitmap_and_compl (to_remove, kills, uses); | |
857 | bitmap_and_compl_into (phis, to_remove); | |
858 | if (bitmap_empty_p (phis)) | |
859 | { | |
860 | BITMAP_FREE (to_remove); | |
861 | return; | |
862 | } | |
863 | ||
864 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
865 | liveness information, as that may be linear in the size of CFG, and if | |
866 | there are lot of different variables to rewrite, this may lead to quadratic | |
867 | behavior. | |
868 | ||
869 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
870 | then for each of them find the nearest def that dominates them. If this | |
871 | def is a phi node, we mark it live, and if it was not live before, we | |
872 | add the predecessors of its basic block to the worklist. | |
48e1416a | 873 | |
f50cf978 | 874 | To quickly locate the nearest def that dominates use, we use dfs numbering |
875 | of the dominance tree (that is already available in order to speed up | |
876 | queries). For each def, we have the interval given by the dfs number on | |
877 | entry to and on exit from the corresponding subtree in the dominance tree. | |
878 | The nearest dominator for a given use is the smallest of these intervals | |
879 | that contains entry and exit dfs numbers for the basic block with the use. | |
880 | If we store the bounds for all the uses to an array and sort it, we can | |
881 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
882 | bitmap_ior (to_remove, kills, phis); | |
883 | n_defs = bitmap_count_bits (to_remove); | |
884 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
885 | defs[0].bb_index = 1; | |
886 | defs[0].dfs_num = 0; | |
887 | adef = 1; | |
888 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
889 | { | |
890 | def_bb = BASIC_BLOCK (i); | |
891 | defs[adef].bb_index = i; | |
892 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
893 | defs[adef + 1].bb_index = i; | |
894 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
895 | adef += 2; | |
896 | } | |
897 | BITMAP_FREE (to_remove); | |
898 | gcc_assert (adef == 2 * n_defs + 1); | |
899 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
900 | gcc_assert (defs[0].bb_index == 1); | |
901 | ||
902 | /* Now each DEFS entry contains the number of the basic block to that the | |
903 | dfs number corresponds. Change them to the number of basic block that | |
904 | corresponds to the interval following the dfs number. Also, for the | |
905 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
906 | to the start of the following interval, not to the end of the current | |
907 | one). We use WORKLIST as a stack. */ | |
908 | worklist = VEC_alloc (int, heap, n_defs + 1); | |
909 | VEC_quick_push (int, worklist, 1); | |
910 | top = 1; | |
911 | n_defs = 1; | |
912 | for (i = 1; i < adef; i++) | |
913 | { | |
914 | b = defs[i].bb_index; | |
915 | if (b == top) | |
916 | { | |
917 | /* This is a closing element. Interval corresponding to the top | |
918 | of the stack after removing it follows. */ | |
919 | VEC_pop (int, worklist); | |
920 | top = VEC_index (int, worklist, VEC_length (int, worklist) - 1); | |
921 | defs[n_defs].bb_index = top; | |
922 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
923 | } | |
924 | else | |
925 | { | |
926 | /* Opening element. Nothing to do, just push it to the stack and move | |
927 | it to the correct position. */ | |
928 | defs[n_defs].bb_index = defs[i].bb_index; | |
929 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
930 | VEC_quick_push (int, worklist, b); | |
931 | top = b; | |
932 | } | |
933 | ||
934 | /* If this interval starts at the same point as the previous one, cancel | |
935 | the previous one. */ | |
936 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
937 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
938 | else | |
939 | n_defs++; | |
940 | } | |
941 | VEC_pop (int, worklist); | |
942 | gcc_assert (VEC_empty (int, worklist)); | |
943 | ||
944 | /* Now process the uses. */ | |
945 | live_phis = BITMAP_ALLOC (NULL); | |
946 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
947 | { | |
948 | VEC_safe_push (int, heap, worklist, i); | |
949 | } | |
950 | ||
951 | while (!VEC_empty (int, worklist)) | |
952 | { | |
953 | b = VEC_pop (int, worklist); | |
954 | if (b == ENTRY_BLOCK) | |
955 | continue; | |
956 | ||
957 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
958 | find the def that dominates the immediate dominator of USE_BB | |
959 | (the kill in USE_BB does not dominate the use). */ | |
960 | if (bitmap_bit_p (phis, b)) | |
961 | p = b; | |
962 | else | |
963 | { | |
964 | use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b)); | |
965 | p = find_dfsnum_interval (defs, n_defs, | |
966 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
967 | if (!bitmap_bit_p (phis, p)) | |
968 | continue; | |
969 | } | |
970 | ||
971 | /* If the phi node is already live, there is nothing to do. */ | |
6ef9bbe0 | 972 | if (!bitmap_set_bit (live_phis, p)) |
f50cf978 | 973 | continue; |
974 | ||
6ef9bbe0 | 975 | /* Add the new uses to the worklist. */ |
f50cf978 | 976 | def_bb = BASIC_BLOCK (p); |
977 | FOR_EACH_EDGE (e, ei, def_bb->preds) | |
978 | { | |
979 | u = e->src->index; | |
980 | if (bitmap_bit_p (uses, u)) | |
981 | continue; | |
982 | ||
94858f65 | 983 | /* In case there is a kill directly in the use block, do not record |
984 | the use (this is also necessary for correctness, as we assume that | |
985 | uses dominated by a def directly in their block have been filtered | |
986 | out before). */ | |
987 | if (bitmap_bit_p (kills, u)) | |
988 | continue; | |
989 | ||
f50cf978 | 990 | bitmap_set_bit (uses, u); |
991 | VEC_safe_push (int, heap, worklist, u); | |
992 | } | |
993 | } | |
994 | ||
995 | VEC_free (int, heap, worklist); | |
996 | bitmap_copy (phis, live_phis); | |
997 | BITMAP_FREE (live_phis); | |
998 | free (defs); | |
999 | } | |
e551bd1a | 1000 | |
e551bd1a | 1001 | /* Return the set of blocks where variable VAR is defined and the blocks |
1002 | where VAR is live on entry (livein). Return NULL, if no entry is | |
1003 | found in DEF_BLOCKS. */ | |
1004 | ||
1005 | static inline struct def_blocks_d * | |
1006 | find_def_blocks_for (tree var) | |
1007 | { | |
1008 | struct def_blocks_d dm; | |
1009 | dm.var = var; | |
1010 | return (struct def_blocks_d *) htab_find (def_blocks, &dm); | |
1011 | } | |
1012 | ||
1013 | ||
88dbf20f | 1014 | /* Retrieve or create a default definition for symbol SYM. */ |
1015 | ||
1016 | static inline tree | |
1017 | get_default_def_for (tree sym) | |
1018 | { | |
2d04fd8d | 1019 | tree ddef = gimple_default_def (cfun, sym); |
88dbf20f | 1020 | |
1021 | if (ddef == NULL_TREE) | |
1022 | { | |
75a70cf9 | 1023 | ddef = make_ssa_name (sym, gimple_build_nop ()); |
88dbf20f | 1024 | set_default_def (sym, ddef); |
1025 | } | |
1026 | ||
1027 | return ddef; | |
1028 | } | |
1029 | ||
1030 | ||
70630fcd | 1031 | /* Marks phi node PHI in basic block BB for rewrite. */ |
1032 | ||
1033 | static void | |
75a70cf9 | 1034 | mark_phi_for_rewrite (basic_block bb, gimple phi) |
70630fcd | 1035 | { |
75a70cf9 | 1036 | gimple_vec phis; |
70630fcd | 1037 | unsigned i, idx = bb->index; |
1038 | ||
75a70cf9 | 1039 | if (rewrite_uses_p (phi)) |
70630fcd | 1040 | return; |
4fb5e5ca | 1041 | |
75a70cf9 | 1042 | set_rewrite_uses (phi, true); |
70630fcd | 1043 | |
1044 | if (!blocks_with_phis_to_rewrite) | |
1045 | return; | |
1046 | ||
1047 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
75a70cf9 | 1048 | VEC_reserve (gimple_vec, heap, phis_to_rewrite, last_basic_block + 1); |
1049 | for (i = VEC_length (gimple_vec, phis_to_rewrite); i <= idx; i++) | |
1050 | VEC_quick_push (gimple_vec, phis_to_rewrite, NULL); | |
70630fcd | 1051 | |
75a70cf9 | 1052 | phis = VEC_index (gimple_vec, phis_to_rewrite, idx); |
70630fcd | 1053 | if (!phis) |
75a70cf9 | 1054 | phis = VEC_alloc (gimple, heap, 10); |
70630fcd | 1055 | |
75a70cf9 | 1056 | VEC_safe_push (gimple, heap, phis, phi); |
1057 | VEC_replace (gimple_vec, phis_to_rewrite, idx, phis); | |
70630fcd | 1058 | } |
1059 | ||
e551bd1a | 1060 | /* Insert PHI nodes for variable VAR using the iterated dominance |
88dbf20f | 1061 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
4fb5e5ca | 1062 | function assumes that the caller is incrementally updating the |
1063 | existing SSA form, in which case VAR may be an SSA name instead of | |
1064 | a symbol. | |
88dbf20f | 1065 | |
1066 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
1067 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
1068 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
e551bd1a | 1069 | |
1070 | static void | |
88dbf20f | 1071 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
e551bd1a | 1072 | { |
1073 | unsigned bb_index; | |
1074 | edge e; | |
75a70cf9 | 1075 | gimple phi; |
e551bd1a | 1076 | basic_block bb; |
1077 | bitmap_iterator bi; | |
1078 | struct def_blocks_d *def_map; | |
1079 | ||
1080 | def_map = find_def_blocks_for (var); | |
88dbf20f | 1081 | gcc_assert (def_map); |
e551bd1a | 1082 | |
1083 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
1084 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
1085 | ||
f50cf978 | 1086 | /* Remove obviously useless phi nodes. */ |
1087 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
1088 | def_map->livein_blocks); | |
e551bd1a | 1089 | |
1090 | /* And insert the PHI nodes. */ | |
f50cf978 | 1091 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
e551bd1a | 1092 | { |
1093 | bb = BASIC_BLOCK (bb_index); | |
2920559d | 1094 | if (update_p) |
1095 | mark_block_for_update (bb); | |
e551bd1a | 1096 | |
75a70cf9 | 1097 | phi = NULL; |
4fb5e5ca | 1098 | |
1099 | if (TREE_CODE (var) == SSA_NAME) | |
e551bd1a | 1100 | { |
095dcfa3 | 1101 | /* If we are rewriting SSA names, create the LHS of the PHI |
1102 | node by duplicating VAR. This is useful in the case of | |
1103 | pointers, to also duplicate pointer attributes (alias | |
1104 | information, in particular). */ | |
e551bd1a | 1105 | edge_iterator ei; |
095dcfa3 | 1106 | tree new_lhs; |
88dbf20f | 1107 | |
4fb5e5ca | 1108 | gcc_assert (update_p); |
095dcfa3 | 1109 | phi = create_phi_node (var, bb); |
4fb5e5ca | 1110 | |
095dcfa3 | 1111 | new_lhs = duplicate_ssa_name (var, phi); |
75a70cf9 | 1112 | gimple_phi_set_result (phi, new_lhs); |
095dcfa3 | 1113 | add_new_name_mapping (new_lhs, var); |
88dbf20f | 1114 | |
1115 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1116 | every argument so that rewrite_update_phi_arguments knows | |
1117 | which name is this PHI node replacing. If VAR is a | |
1118 | symbol marked for renaming, this is not necessary, the | |
1119 | renamer will use the symbol on the LHS to get its | |
1120 | reaching definition. */ | |
e551bd1a | 1121 | FOR_EACH_EDGE (e, ei, bb->preds) |
efbcb6de | 1122 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
e551bd1a | 1123 | } |
095dcfa3 | 1124 | else |
1125 | { | |
9845d120 | 1126 | tree tracked_var; |
cd610ee6 | 1127 | |
25ae9ba2 | 1128 | gcc_assert (DECL_P (var)); |
1129 | phi = create_phi_node (var, bb); | |
cd610ee6 | 1130 | |
1131 | tracked_var = target_for_debug_bind (var); | |
1132 | if (tracked_var) | |
9845d120 | 1133 | { |
1134 | gimple note = gimple_build_debug_bind (tracked_var, | |
1135 | PHI_RESULT (phi), | |
1136 | phi); | |
1137 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1138 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1139 | } | |
095dcfa3 | 1140 | } |
88dbf20f | 1141 | |
1142 | /* Mark this PHI node as interesting for update_ssa. */ | |
75a70cf9 | 1143 | set_register_defs (phi, true); |
70630fcd | 1144 | mark_phi_for_rewrite (bb, phi); |
e551bd1a | 1145 | } |
1146 | } | |
1147 | ||
1148 | ||
e551bd1a | 1149 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1150 | definitions. DFS contains the dominance frontier information for | |
4fb5e5ca | 1151 | the flowgraph. */ |
e551bd1a | 1152 | |
1153 | static void | |
8a2980be | 1154 | insert_phi_nodes (bitmap_head *dfs) |
e551bd1a | 1155 | { |
a55dc2cd | 1156 | referenced_var_iterator rvi; |
409a375f | 1157 | bitmap_iterator bi; |
a55dc2cd | 1158 | tree var; |
409a375f | 1159 | bitmap vars; |
1160 | unsigned uid; | |
e551bd1a | 1161 | |
1162 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
48e1416a | 1163 | |
409a375f | 1164 | /* Do two stages to avoid code generation differences for UID |
1165 | differences but no UID ordering differences. */ | |
1166 | ||
1167 | vars = BITMAP_ALLOC (NULL); | |
a23e00ae | 1168 | FOR_EACH_REFERENCED_VAR (cfun, var, rvi) |
f3d9a16c | 1169 | { |
095dcfa3 | 1170 | struct def_blocks_d *def_map; |
88dbf20f | 1171 | |
095dcfa3 | 1172 | def_map = find_def_blocks_for (var); |
1173 | if (def_map == NULL) | |
1174 | continue; | |
1175 | ||
1176 | if (get_phi_state (var) != NEED_PHI_STATE_NO) | |
409a375f | 1177 | bitmap_set_bit (vars, DECL_UID (var)); |
e551bd1a | 1178 | } |
f3d9a16c | 1179 | |
409a375f | 1180 | EXECUTE_IF_SET_IN_BITMAP (vars, 0, uid, bi) |
1181 | { | |
1182 | tree var = referenced_var (uid); | |
1183 | struct def_blocks_d *def_map; | |
1184 | bitmap idf; | |
1185 | ||
1186 | def_map = find_def_blocks_for (var); | |
1187 | idf = compute_idf (def_map->def_blocks, dfs); | |
1188 | insert_phi_nodes_for (var, idf, false); | |
1189 | BITMAP_FREE (idf); | |
1190 | } | |
1191 | ||
1192 | BITMAP_FREE (vars); | |
1193 | ||
4ee9c684 | 1194 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1195 | } | |
1196 | ||
1197 | ||
4fb5e5ca | 1198 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1199 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
e551bd1a | 1200 | |
de6ed584 | 1201 | static void |
4fb5e5ca | 1202 | register_new_def (tree def, tree sym) |
e551bd1a | 1203 | { |
e551bd1a | 1204 | tree currdef; |
48e1416a | 1205 | |
e551bd1a | 1206 | /* If this variable is set in a single basic block and all uses are |
1207 | dominated by the set(s) in that single basic block, then there is | |
1208 | no reason to record anything for this variable in the block local | |
1209 | definition stacks. Doing so just wastes time and memory. | |
1210 | ||
1211 | This is the same test to prune the set of variables which may | |
1212 | need PHI nodes. So we just use that information since it's already | |
1213 | computed and available for us to use. */ | |
4fb5e5ca | 1214 | if (get_phi_state (sym) == NEED_PHI_STATE_NO) |
e551bd1a | 1215 | { |
4fb5e5ca | 1216 | set_current_def (sym, def); |
e551bd1a | 1217 | return; |
1218 | } | |
1219 | ||
4fb5e5ca | 1220 | currdef = get_current_def (sym); |
e551bd1a | 1221 | |
4fb5e5ca | 1222 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1223 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1224 | in the stack so that we know which symbol is being defined by | |
1225 | this SSA name when we unwind the stack. */ | |
1226 | if (currdef && !is_gimple_reg (sym)) | |
1227 | VEC_safe_push (tree, heap, block_defs_stack, sym); | |
e551bd1a | 1228 | |
4fb5e5ca | 1229 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1230 | stack is later used by the dominator tree callbacks to restore | |
1231 | the reaching definitions for all the variables defined in the | |
1232 | block after a recursive visit to all its immediately dominated | |
1233 | blocks. If there is no current reaching definition, then just | |
1234 | record the underlying _DECL node. */ | |
1235 | VEC_safe_push (tree, heap, block_defs_stack, currdef ? currdef : sym); | |
1236 | ||
1237 | /* Set the current reaching definition for SYM to be DEF. */ | |
1238 | set_current_def (sym, def); | |
e551bd1a | 1239 | } |
1240 | ||
1241 | ||
4ee9c684 | 1242 | /* Perform a depth-first traversal of the dominator tree looking for |
1243 | variables to rename. BB is the block where to start searching. | |
1244 | Renaming is a five step process: | |
1245 | ||
1246 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1247 | registered as the current definition for the corresponding variable. | |
1248 | ||
1249 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1250 | rewritten with their corresponding reaching definition. DEF and | |
1251 | VDEF targets are registered as new definitions. | |
48e1416a | 1252 | |
4ee9c684 | 1253 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1254 | argument corresponding to BB is replaced with its current reaching | |
1255 | definition. | |
1256 | ||
1257 | 4- Recursively rewrite every dominator child block of BB. | |
1258 | ||
1259 | 5- Restore (in reverse order) the current reaching definition for every | |
1260 | new definition introduced in this block. This is done so that when | |
1261 | we return from the recursive call, all the current reaching | |
1262 | definitions are restored to the names that were valid in the | |
1263 | dominator parent of BB. */ | |
1264 | ||
e551bd1a | 1265 | /* Return the current definition for variable VAR. If none is found, |
4fb5e5ca | 1266 | create a new SSA name to act as the zeroth definition for VAR. */ |
f3d9a16c | 1267 | |
e551bd1a | 1268 | static tree |
1269 | get_reaching_def (tree var) | |
1270 | { | |
4fb5e5ca | 1271 | tree currdef; |
48e1416a | 1272 | |
e551bd1a | 1273 | /* Lookup the current reaching definition for VAR. */ |
4fb5e5ca | 1274 | currdef = get_current_def (var); |
f3d9a16c | 1275 | |
e551bd1a | 1276 | /* If there is no reaching definition for VAR, create and register a |
1277 | default definition for it (if needed). */ | |
4fb5e5ca | 1278 | if (currdef == NULL_TREE) |
e551bd1a | 1279 | { |
4fb5e5ca | 1280 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
1281 | currdef = get_default_def_for (sym); | |
1282 | set_current_def (var, currdef); | |
e551bd1a | 1283 | } |
1284 | ||
1285 | /* Return the current reaching definition for VAR, or the default | |
1286 | definition, if we had to create one. */ | |
4fb5e5ca | 1287 | return currdef; |
e551bd1a | 1288 | } |
1289 | ||
1290 | ||
841424cc | 1291 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1292 | ||
1293 | static void | |
1294 | rewrite_debug_stmt_uses (gimple stmt) | |
1295 | { | |
1296 | use_operand_p use_p; | |
1297 | ssa_op_iter iter; | |
1298 | bool update = false; | |
1299 | ||
1300 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1301 | { | |
1302 | tree var = USE_FROM_PTR (use_p), def = NULL_TREE; | |
1303 | gcc_assert (DECL_P (var)); | |
1304 | if (var_ann (var) == NULL) | |
1305 | { | |
1306 | if (TREE_CODE (var) == PARM_DECL && single_succ_p (ENTRY_BLOCK_PTR)) | |
1307 | { | |
1308 | gimple_stmt_iterator gsi | |
1309 | = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1310 | int lim; | |
1311 | /* Search a few source bind stmts at the start of first bb to | |
1312 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1313 | for (lim = 32; | |
1314 | !gsi_end_p (gsi) && lim > 0; | |
1315 | gsi_next (&gsi), lim--) | |
1316 | { | |
1317 | gimple gstmt = gsi_stmt (gsi); | |
1318 | if (!gimple_debug_source_bind_p (gstmt)) | |
1319 | break; | |
1320 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1321 | { | |
1322 | def = gimple_debug_source_bind_get_var (gstmt); | |
1323 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1324 | break; | |
1325 | else | |
1326 | def = NULL_TREE; | |
1327 | } | |
1328 | } | |
1329 | /* If not, add a new source bind stmt. */ | |
1330 | if (def == NULL_TREE) | |
1331 | { | |
1332 | gimple def_temp; | |
1333 | def = make_node (DEBUG_EXPR_DECL); | |
1334 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1335 | DECL_ARTIFICIAL (def) = 1; | |
1336 | TREE_TYPE (def) = TREE_TYPE (var); | |
1337 | DECL_MODE (def) = DECL_MODE (var); | |
1338 | gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1339 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); | |
1340 | } | |
1341 | update = true; | |
1342 | } | |
1343 | } | |
1344 | else | |
824651eb | 1345 | { |
1346 | def = get_current_def (var); | |
1347 | /* Check if get_current_def can be trusted. */ | |
1348 | if (def) | |
1349 | { | |
1350 | basic_block bb = gimple_bb (stmt); | |
1351 | basic_block def_bb | |
1352 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1353 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1354 | ||
1355 | /* If definition is in current bb, it is fine. */ | |
1356 | if (bb == def_bb) | |
1357 | ; | |
1358 | /* If definition bb doesn't dominate the current bb, | |
1359 | it can't be used. */ | |
1360 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1361 | def = NULL; | |
1362 | /* If there is just one definition and dominates the current | |
1363 | bb, it is fine. */ | |
1364 | else if (get_phi_state (var) == NEED_PHI_STATE_NO) | |
1365 | ; | |
1366 | else | |
1367 | { | |
1368 | struct def_blocks_d *db_p = get_def_blocks_for (var); | |
1369 | ||
1370 | /* If there are some non-debug uses in the current bb, | |
1371 | it is fine. */ | |
1372 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
1373 | ; | |
1374 | /* Otherwise give up for now. */ | |
1375 | else | |
1376 | def = NULL; | |
1377 | } | |
1378 | } | |
1379 | } | |
841424cc | 1380 | if (def == NULL) |
1381 | { | |
1382 | gimple_debug_bind_reset_value (stmt); | |
1383 | update_stmt (stmt); | |
1384 | return; | |
1385 | } | |
1386 | SET_USE (use_p, def); | |
1387 | } | |
1388 | if (update) | |
1389 | update_stmt (stmt); | |
1390 | } | |
1391 | ||
e551bd1a | 1392 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1393 | the block with its immediate reaching definitions. Update the current | |
1394 | definition of a variable when a new real or virtual definition is found. */ | |
f3d9a16c | 1395 | |
1396 | static void | |
9845d120 | 1397 | rewrite_stmt (gimple_stmt_iterator si) |
f3d9a16c | 1398 | { |
e551bd1a | 1399 | use_operand_p use_p; |
1400 | def_operand_p def_p; | |
1401 | ssa_op_iter iter; | |
9845d120 | 1402 | gimple stmt = gsi_stmt (si); |
e551bd1a | 1403 | |
e551bd1a | 1404 | /* If mark_def_sites decided that we don't need to rewrite this |
1405 | statement, ignore it. */ | |
2920559d | 1406 | gcc_assert (blocks_to_update == NULL); |
75a70cf9 | 1407 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
e551bd1a | 1408 | return; |
f3d9a16c | 1409 | |
1410 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
e551bd1a | 1411 | { |
1412 | fprintf (dump_file, "Renaming statement "); | |
75a70cf9 | 1413 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
e551bd1a | 1414 | fprintf (dump_file, "\n"); |
1415 | } | |
f3d9a16c | 1416 | |
4fb5e5ca | 1417 | /* Step 1. Rewrite USES in the statement. */ |
75a70cf9 | 1418 | if (rewrite_uses_p (stmt)) |
841424cc | 1419 | { |
1420 | if (is_gimple_debug (stmt)) | |
1421 | rewrite_debug_stmt_uses (stmt); | |
1422 | else | |
1423 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1424 | { | |
1425 | tree var = USE_FROM_PTR (use_p); | |
1426 | gcc_assert (DECL_P (var)); | |
1427 | SET_USE (use_p, get_reaching_def (var)); | |
1428 | } | |
1429 | } | |
f3d9a16c | 1430 | |
4fb5e5ca | 1431 | /* Step 2. Register the statement's DEF operands. */ |
75a70cf9 | 1432 | if (register_defs_p (stmt)) |
4fb5e5ca | 1433 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) |
88dbf20f | 1434 | { |
1435 | tree var = DEF_FROM_PTR (def_p); | |
9845d120 | 1436 | tree name = make_ssa_name (var, stmt); |
1437 | tree tracked_var; | |
88dbf20f | 1438 | gcc_assert (DECL_P (var)); |
9845d120 | 1439 | SET_DEF (def_p, name); |
4fb5e5ca | 1440 | register_new_def (DEF_FROM_PTR (def_p), var); |
9845d120 | 1441 | |
1442 | tracked_var = target_for_debug_bind (var); | |
1443 | if (tracked_var) | |
1444 | { | |
1445 | gimple note = gimple_build_debug_bind (tracked_var, name, stmt); | |
1446 | gsi_insert_after (&si, note, GSI_SAME_STMT); | |
1447 | } | |
88dbf20f | 1448 | } |
f3d9a16c | 1449 | } |
4ee9c684 | 1450 | |
e551bd1a | 1451 | |
4ee9c684 | 1452 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1453 | PHI nodes. For every PHI node found, add a new argument containing the | |
1454 | current reaching definition for the variable and the edge through which | |
dac49aa5 | 1455 | that definition is reaching the PHI node. */ |
4ee9c684 | 1456 | |
1457 | static void | |
6bf320fb | 1458 | rewrite_add_phi_arguments (basic_block bb) |
4ee9c684 | 1459 | { |
1460 | edge e; | |
cd665a06 | 1461 | edge_iterator ei; |
4ee9c684 | 1462 | |
cd665a06 | 1463 | FOR_EACH_EDGE (e, ei, bb->succs) |
4ee9c684 | 1464 | { |
75a70cf9 | 1465 | gimple phi; |
1466 | gimple_stmt_iterator gsi; | |
4ee9c684 | 1467 | |
75a70cf9 | 1468 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1469 | gsi_next (&gsi)) | |
4ee9c684 | 1470 | { |
1471 | tree currdef; | |
efbcb6de | 1472 | gimple stmt; |
1473 | ||
75a70cf9 | 1474 | phi = gsi_stmt (gsi); |
1475 | currdef = get_reaching_def (SSA_NAME_VAR (gimple_phi_result (phi))); | |
efbcb6de | 1476 | stmt = SSA_NAME_DEF_STMT (currdef); |
1477 | add_phi_arg (phi, currdef, e, gimple_location (stmt)); | |
4ee9c684 | 1478 | } |
1479 | } | |
1480 | } | |
1481 | ||
6bf320fb | 1482 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1483 | of reaching definitions for new SSA names produced in this block | |
1484 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1485 | block. */ | |
1486 | ||
1487 | static void | |
1488 | rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1489 | basic_block bb) | |
1490 | { | |
1491 | gimple phi; | |
1492 | gimple_stmt_iterator gsi; | |
1493 | ||
1494 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1495 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1496 | ||
1497 | /* Mark the unwind point for this block. */ | |
1498 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
1499 | ||
1500 | /* Step 1. Register new definitions for every PHI node in the block. | |
1501 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1502 | node introduces a new version for the associated variable. */ | |
1503 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1504 | { | |
1505 | tree result; | |
1506 | ||
1507 | phi = gsi_stmt (gsi); | |
1508 | result = gimple_phi_result (phi); | |
1509 | gcc_assert (is_gimple_reg (result)); | |
1510 | register_new_def (result, SSA_NAME_VAR (result)); | |
1511 | } | |
1512 | ||
1513 | /* Step 2. Rewrite every variable used in each statement in the block | |
1514 | with its immediate reaching definitions. Update the current definition | |
1515 | of a variable when a new real or virtual definition is found. */ | |
1516 | if (TEST_BIT (interesting_blocks, bb->index)) | |
1517 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
9845d120 | 1518 | rewrite_stmt (gsi); |
6bf320fb | 1519 | |
1520 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1521 | For every PHI node found, add a new argument containing the current | |
1522 | reaching definition for the variable and the edge through which that | |
1523 | definition is reaching the PHI node. */ | |
1524 | rewrite_add_phi_arguments (bb); | |
1525 | } | |
1526 | ||
1527 | ||
e551bd1a | 1528 | |
4fb5e5ca | 1529 | /* Called after visiting all the statements in basic block BB and all |
1530 | of its dominator children. Restore CURRDEFS to its original value. */ | |
4ee9c684 | 1531 | |
1532 | static void | |
6bf320fb | 1533 | rewrite_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1534 | basic_block bb ATTRIBUTE_UNUSED) | |
4ee9c684 | 1535 | { |
dd2d357d | 1536 | /* Restore CURRDEFS to its original state. */ |
046bfc77 | 1537 | while (VEC_length (tree, block_defs_stack) > 0) |
4ee9c684 | 1538 | { |
046bfc77 | 1539 | tree tmp = VEC_pop (tree, block_defs_stack); |
4ee9c684 | 1540 | tree saved_def, var; |
1541 | ||
dd2d357d | 1542 | if (tmp == NULL_TREE) |
1543 | break; | |
1544 | ||
4ee9c684 | 1545 | if (TREE_CODE (tmp) == SSA_NAME) |
1546 | { | |
4fb5e5ca | 1547 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1548 | current definition of its underlying variable. Note that | |
1549 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1550 | being defined is stored in the next slot in the stack. | |
1551 | This mechanism is needed because an SSA name for a | |
1552 | non-register symbol may be the definition for more than | |
1553 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
4ee9c684 | 1554 | saved_def = tmp; |
1555 | var = SSA_NAME_VAR (saved_def); | |
4fb5e5ca | 1556 | if (!is_gimple_reg (var)) |
1557 | var = VEC_pop (tree, block_defs_stack); | |
4ee9c684 | 1558 | } |
1559 | else | |
1560 | { | |
4fb5e5ca | 1561 | /* If we recorded anything else, it must have been a _DECL |
1562 | node and its current reaching definition must have been | |
1563 | NULL. */ | |
4ee9c684 | 1564 | saved_def = NULL; |
1565 | var = tmp; | |
1566 | } | |
48e1416a | 1567 | |
f3d9a16c | 1568 | set_current_def (var, saved_def); |
4ee9c684 | 1569 | } |
1570 | } | |
1571 | ||
1572 | ||
4fb5e5ca | 1573 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1574 | ||
1575 | void | |
1576 | dump_decl_set (FILE *file, bitmap set) | |
1577 | { | |
1578 | if (set) | |
1579 | { | |
c0ff55b3 | 1580 | bitmap_iterator bi; |
1581 | unsigned i; | |
4fb5e5ca | 1582 | |
1583 | fprintf (file, "{ "); | |
1584 | ||
c0ff55b3 | 1585 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
4fb5e5ca | 1586 | { |
29e4566c | 1587 | tree var = referenced_var_lookup (cfun, i); |
1a981e1a | 1588 | if (var) |
1589 | print_generic_expr (file, var, 0); | |
1590 | else | |
1591 | fprintf (file, "D.%u", i); | |
4fb5e5ca | 1592 | fprintf (file, " "); |
1593 | } | |
1594 | ||
dd277d48 | 1595 | fprintf (file, "}"); |
4fb5e5ca | 1596 | } |
1597 | else | |
dd277d48 | 1598 | fprintf (file, "NIL"); |
4fb5e5ca | 1599 | } |
1600 | ||
1601 | ||
1602 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ | |
1603 | ||
4b987fac | 1604 | DEBUG_FUNCTION void |
4fb5e5ca | 1605 | debug_decl_set (bitmap set) |
1606 | { | |
1607 | dump_decl_set (stderr, set); | |
dd277d48 | 1608 | fprintf (stderr, "\n"); |
4fb5e5ca | 1609 | } |
1610 | ||
1611 | ||
1612 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1613 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1614 | dumped. New levels are created when the dominator tree traversal | |
1615 | used for renaming enters a new sub-tree. */ | |
1616 | ||
1617 | void | |
1618 | dump_defs_stack (FILE *file, int n) | |
1619 | { | |
1620 | int i, j; | |
1621 | ||
1622 | fprintf (file, "\n\nRenaming stack"); | |
1623 | if (n > 0) | |
1624 | fprintf (file, " (up to %d levels)", n); | |
1625 | fprintf (file, "\n\n"); | |
1626 | ||
1627 | i = 1; | |
1628 | fprintf (file, "Level %d (current level)\n", i); | |
1629 | for (j = (int) VEC_length (tree, block_defs_stack) - 1; j >= 0; j--) | |
1630 | { | |
1631 | tree name, var; | |
48e1416a | 1632 | |
4fb5e5ca | 1633 | name = VEC_index (tree, block_defs_stack, j); |
1634 | if (name == NULL_TREE) | |
1635 | { | |
1636 | i++; | |
1637 | if (n > 0 && i > n) | |
1638 | break; | |
1639 | fprintf (file, "\nLevel %d\n", i); | |
1640 | continue; | |
1641 | } | |
1642 | ||
1643 | if (DECL_P (name)) | |
1644 | { | |
1645 | var = name; | |
1646 | name = NULL_TREE; | |
1647 | } | |
1648 | else | |
1649 | { | |
1650 | var = SSA_NAME_VAR (name); | |
1651 | if (!is_gimple_reg (var)) | |
1652 | { | |
1653 | j--; | |
1654 | var = VEC_index (tree, block_defs_stack, j); | |
1655 | } | |
1656 | } | |
1657 | ||
1658 | fprintf (file, " Previous CURRDEF ("); | |
1659 | print_generic_expr (file, var, 0); | |
1660 | fprintf (file, ") = "); | |
1661 | if (name) | |
1662 | print_generic_expr (file, name, 0); | |
1663 | else | |
1664 | fprintf (file, "<NIL>"); | |
1665 | fprintf (file, "\n"); | |
1666 | } | |
1667 | } | |
1668 | ||
1669 | ||
1670 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1671 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1672 | dumped. New levels are created when the dominator tree traversal | |
1673 | used for renaming enters a new sub-tree. */ | |
1674 | ||
4b987fac | 1675 | DEBUG_FUNCTION void |
4fb5e5ca | 1676 | debug_defs_stack (int n) |
1677 | { | |
1678 | dump_defs_stack (stderr, n); | |
1679 | } | |
1680 | ||
1681 | ||
1682 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1683 | ||
1684 | void | |
1685 | dump_currdefs (FILE *file) | |
1686 | { | |
1687 | referenced_var_iterator i; | |
1688 | tree var; | |
1689 | ||
1690 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); | |
a23e00ae | 1691 | FOR_EACH_REFERENCED_VAR (cfun, var, i) |
dd277d48 | 1692 | if (SYMS_TO_RENAME (cfun) == NULL |
1693 | || bitmap_bit_p (SYMS_TO_RENAME (cfun), DECL_UID (var))) | |
4fb5e5ca | 1694 | { |
1695 | fprintf (file, "CURRDEF ("); | |
1696 | print_generic_expr (file, var, 0); | |
1697 | fprintf (file, ") = "); | |
1698 | if (get_current_def (var)) | |
1699 | print_generic_expr (file, get_current_def (var), 0); | |
1700 | else | |
1701 | fprintf (file, "<NIL>"); | |
1702 | fprintf (file, "\n"); | |
1703 | } | |
1704 | } | |
1705 | ||
1706 | ||
1707 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1708 | ||
4b987fac | 1709 | DEBUG_FUNCTION void |
4fb5e5ca | 1710 | debug_currdefs (void) |
1711 | { | |
1712 | dump_currdefs (stderr); | |
1713 | } | |
1714 | ||
1715 | ||
4ee9c684 | 1716 | /* Dump SSA information to FILE. */ |
1717 | ||
1718 | void | |
1719 | dump_tree_ssa (FILE *file) | |
1720 | { | |
4ee9c684 | 1721 | const char *funcname |
5135beeb | 1722 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
4ee9c684 | 1723 | |
4fb5e5ca | 1724 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
4ee9c684 | 1725 | |
4fb5e5ca | 1726 | dump_def_blocks (file); |
1727 | dump_defs_stack (file, -1); | |
1728 | dump_currdefs (file); | |
1729 | dump_tree_ssa_stats (file); | |
4ee9c684 | 1730 | } |
1731 | ||
1732 | ||
1733 | /* Dump SSA information to stderr. */ | |
1734 | ||
4b987fac | 1735 | DEBUG_FUNCTION void |
4ee9c684 | 1736 | debug_tree_ssa (void) |
1737 | { | |
1738 | dump_tree_ssa (stderr); | |
1739 | } | |
1740 | ||
1741 | ||
e551bd1a | 1742 | /* Dump statistics for the hash table HTAB. */ |
1743 | ||
1744 | static void | |
1745 | htab_statistics (FILE *file, htab_t htab) | |
1746 | { | |
1747 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1748 | (long) htab_size (htab), | |
1749 | (long) htab_elements (htab), | |
1750 | htab_collisions (htab)); | |
1751 | } | |
1752 | ||
1753 | ||
4ee9c684 | 1754 | /* Dump SSA statistics on FILE. */ |
1755 | ||
1756 | void | |
1757 | dump_tree_ssa_stats (FILE *file) | |
1758 | { | |
4fb5e5ca | 1759 | if (def_blocks || repl_tbl) |
1760 | fprintf (file, "\nHash table statistics:\n"); | |
4ee9c684 | 1761 | |
4fb5e5ca | 1762 | if (def_blocks) |
1763 | { | |
1764 | fprintf (file, " def_blocks: "); | |
1765 | htab_statistics (file, def_blocks); | |
1766 | } | |
4ee9c684 | 1767 | |
4fb5e5ca | 1768 | if (repl_tbl) |
1769 | { | |
1770 | fprintf (file, " repl_tbl: "); | |
1771 | htab_statistics (file, repl_tbl); | |
1772 | } | |
1773 | ||
1774 | if (def_blocks || repl_tbl) | |
1775 | fprintf (file, "\n"); | |
4ee9c684 | 1776 | } |
1777 | ||
1778 | ||
1779 | /* Dump SSA statistics on stderr. */ | |
1780 | ||
4b987fac | 1781 | DEBUG_FUNCTION void |
4ee9c684 | 1782 | debug_tree_ssa_stats (void) |
1783 | { | |
1784 | dump_tree_ssa_stats (stderr); | |
1785 | } | |
1786 | ||
1787 | ||
e551bd1a | 1788 | /* Hashing and equality functions for DEF_BLOCKS. */ |
4ee9c684 | 1789 | |
e551bd1a | 1790 | static hashval_t |
1791 | def_blocks_hash (const void *p) | |
4ee9c684 | 1792 | { |
e551bd1a | 1793 | return htab_hash_pointer |
1794 | ((const void *)((const struct def_blocks_d *)p)->var); | |
1795 | } | |
1796 | ||
1797 | static int | |
1798 | def_blocks_eq (const void *p1, const void *p2) | |
1799 | { | |
1800 | return ((const struct def_blocks_d *)p1)->var | |
1801 | == ((const struct def_blocks_d *)p2)->var; | |
4ee9c684 | 1802 | } |
1803 | ||
1804 | ||
e551bd1a | 1805 | /* Free memory allocated by one entry in DEF_BLOCKS. */ |
4ee9c684 | 1806 | |
1807 | static void | |
e551bd1a | 1808 | def_blocks_free (void *p) |
4ee9c684 | 1809 | { |
680a19b9 | 1810 | struct def_blocks_d *entry = (struct def_blocks_d *) p; |
e551bd1a | 1811 | BITMAP_FREE (entry->def_blocks); |
1812 | BITMAP_FREE (entry->phi_blocks); | |
1813 | BITMAP_FREE (entry->livein_blocks); | |
1814 | free (entry); | |
1815 | } | |
4ee9c684 | 1816 | |
4ee9c684 | 1817 | |
e551bd1a | 1818 | /* Callback for htab_traverse to dump the DEF_BLOCKS hash table. */ |
4ee9c684 | 1819 | |
e551bd1a | 1820 | static int |
4fb5e5ca | 1821 | debug_def_blocks_r (void **slot, void *data) |
e551bd1a | 1822 | { |
4fb5e5ca | 1823 | FILE *file = (FILE *) data; |
e551bd1a | 1824 | struct def_blocks_d *db_p = (struct def_blocks_d *) *slot; |
48e1416a | 1825 | |
4fb5e5ca | 1826 | fprintf (file, "VAR: "); |
1827 | print_generic_expr (file, db_p->var, dump_flags); | |
1828 | bitmap_print (file, db_p->def_blocks, ", DEF_BLOCKS: { ", "}"); | |
1829 | bitmap_print (file, db_p->livein_blocks, ", LIVEIN_BLOCKS: { ", "}"); | |
1830 | bitmap_print (file, db_p->phi_blocks, ", PHI_BLOCKS: { ", "}\n"); | |
4ee9c684 | 1831 | |
e551bd1a | 1832 | return 1; |
1833 | } | |
4ee9c684 | 1834 | |
4ee9c684 | 1835 | |
4fb5e5ca | 1836 | /* Dump the DEF_BLOCKS hash table on FILE. */ |
1837 | ||
1838 | void | |
1839 | dump_def_blocks (FILE *file) | |
1840 | { | |
1841 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
1842 | if (def_blocks) | |
1843 | htab_traverse (def_blocks, debug_def_blocks_r, file); | |
1844 | } | |
1845 | ||
1846 | ||
e551bd1a | 1847 | /* Dump the DEF_BLOCKS hash table on stderr. */ |
4ee9c684 | 1848 | |
4b987fac | 1849 | DEBUG_FUNCTION void |
e551bd1a | 1850 | debug_def_blocks (void) |
1851 | { | |
4fb5e5ca | 1852 | dump_def_blocks (stderr); |
e551bd1a | 1853 | } |
4ee9c684 | 1854 | |
f3d9a16c | 1855 | |
88dbf20f | 1856 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
4ee9c684 | 1857 | |
88dbf20f | 1858 | static inline void |
1859 | register_new_update_single (tree new_name, tree old_name) | |
1860 | { | |
1861 | tree currdef = get_current_def (old_name); | |
f3d9a16c | 1862 | |
4fb5e5ca | 1863 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
88dbf20f | 1864 | This stack is later used by the dominator tree callbacks to |
1865 | restore the reaching definitions for all the variables | |
1866 | defined in the block after a recursive visit to all its | |
1867 | immediately dominated blocks. */ | |
046bfc77 | 1868 | VEC_reserve (tree, heap, block_defs_stack, 2); |
1869 | VEC_quick_push (tree, block_defs_stack, currdef); | |
1870 | VEC_quick_push (tree, block_defs_stack, old_name); | |
f3d9a16c | 1871 | |
88dbf20f | 1872 | /* Set the current reaching definition for OLD_NAME to be |
1873 | NEW_NAME. */ | |
1874 | set_current_def (old_name, new_name); | |
1875 | } | |
e551bd1a | 1876 | |
4ee9c684 | 1877 | |
88dbf20f | 1878 | /* Register NEW_NAME to be the new reaching definition for all the |
1879 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1880 | replace old SSA names with new ones. */ | |
e551bd1a | 1881 | |
88dbf20f | 1882 | static inline void |
1883 | register_new_update_set (tree new_name, bitmap old_names) | |
1884 | { | |
1885 | bitmap_iterator bi; | |
1886 | unsigned i; | |
e551bd1a | 1887 | |
88dbf20f | 1888 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1889 | register_new_update_single (new_name, ssa_name (i)); | |
4ee9c684 | 1890 | } |
1891 | ||
e551bd1a | 1892 | |
88dbf20f | 1893 | |
095dcfa3 | 1894 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1895 | it is a symbol marked for renaming, replace it with USE_P's current | |
1896 | reaching definition. */ | |
1897 | ||
1898 | static inline void | |
1899 | maybe_replace_use (use_operand_p use_p) | |
1900 | { | |
1901 | tree rdef = NULL_TREE; | |
1902 | tree use = USE_FROM_PTR (use_p); | |
1903 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1904 | ||
1905 | if (symbol_marked_for_renaming (sym)) | |
1906 | rdef = get_reaching_def (sym); | |
1907 | else if (is_old_name (use)) | |
1908 | rdef = get_reaching_def (use); | |
1909 | ||
1910 | if (rdef && rdef != use) | |
1911 | SET_USE (use_p, rdef); | |
1912 | } | |
1913 | ||
1914 | ||
9845d120 | 1915 | /* Same as maybe_replace_use, but without introducing default stmts, |
1916 | returning false to indicate a need to do so. */ | |
1917 | ||
1918 | static inline bool | |
1919 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1920 | { | |
1921 | tree rdef = NULL_TREE; | |
1922 | tree use = USE_FROM_PTR (use_p); | |
1923 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1924 | ||
1925 | if (symbol_marked_for_renaming (sym)) | |
1926 | rdef = get_current_def (sym); | |
1927 | else if (is_old_name (use)) | |
1928 | { | |
1929 | rdef = get_current_def (use); | |
1930 | /* We can't assume that, if there's no current definition, the | |
1931 | default one should be used. It could be the case that we've | |
1932 | rearranged blocks so that the earlier definition no longer | |
1933 | dominates the use. */ | |
1934 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1935 | rdef = use; | |
1936 | } | |
1937 | else | |
1938 | rdef = use; | |
1939 | ||
1940 | if (rdef && rdef != use) | |
1941 | SET_USE (use_p, rdef); | |
1942 | ||
1943 | return rdef != NULL_TREE; | |
1944 | } | |
1945 | ||
1946 | ||
095dcfa3 | 1947 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1948 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1949 | register it as the current definition for the names replaced by | |
1950 | DEF_P. */ | |
1951 | ||
1952 | static inline void | |
cd610ee6 | 1953 | maybe_register_def (def_operand_p def_p, gimple stmt, |
1954 | gimple_stmt_iterator gsi) | |
095dcfa3 | 1955 | { |
1956 | tree def = DEF_FROM_PTR (def_p); | |
1957 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
1958 | ||
4fb5e5ca | 1959 | /* If DEF is a naked symbol that needs renaming, create a new |
1960 | name for it. */ | |
095dcfa3 | 1961 | if (symbol_marked_for_renaming (sym)) |
1962 | { | |
1963 | if (DECL_P (def)) | |
1964 | { | |
cd610ee6 | 1965 | tree tracked_var; |
1966 | ||
095dcfa3 | 1967 | def = make_ssa_name (def, stmt); |
1968 | SET_DEF (def_p, def); | |
cd610ee6 | 1969 | |
1970 | tracked_var = target_for_debug_bind (sym); | |
1971 | if (tracked_var) | |
1972 | { | |
1973 | gimple note = gimple_build_debug_bind (tracked_var, def, stmt); | |
8d7f27c3 | 1974 | /* If stmt ends the bb, insert the debug stmt on the single |
1975 | non-EH edge from the stmt. */ | |
1976 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1977 | { | |
1978 | basic_block bb = gsi_bb (gsi); | |
1979 | edge_iterator ei; | |
1980 | edge e, ef = NULL; | |
1981 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1982 | if (!(e->flags & EDGE_EH)) | |
1983 | { | |
1984 | gcc_assert (!ef); | |
1985 | ef = e; | |
1986 | } | |
36a2709b | 1987 | /* If there are other predecessors to ef->dest, then |
1988 | there must be PHI nodes for the modified | |
1989 | variable, and therefore there will be debug bind | |
1990 | stmts after the PHI nodes. The debug bind notes | |
1991 | we'd insert would force the creation of a new | |
1992 | block (diverging codegen) and be redundant with | |
1993 | the post-PHI bind stmts, so don't add them. | |
1994 | ||
1995 | As for the exit edge, there wouldn't be redundant | |
1996 | bind stmts, but there wouldn't be a PC to bind | |
1997 | them to either, so avoid diverging the CFG. */ | |
1998 | if (ef && single_pred_p (ef->dest) | |
1999 | && ef->dest != EXIT_BLOCK_PTR) | |
2000 | { | |
2001 | /* If there were PHI nodes in the node, we'd | |
2002 | have to make sure the value we're binding | |
2003 | doesn't need rewriting. But there shouldn't | |
2004 | be PHI nodes in a single-predecessor block, | |
2005 | so we just add the note. */ | |
2006 | gsi_insert_on_edge_immediate (ef, note); | |
2007 | } | |
8d7f27c3 | 2008 | } |
2009 | else | |
2010 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
cd610ee6 | 2011 | } |
095dcfa3 | 2012 | } |
2013 | ||
2014 | register_new_update_single (def, sym); | |
2015 | } | |
2016 | else | |
2017 | { | |
2018 | /* If DEF is a new name, register it as a new definition | |
2019 | for all the names replaced by DEF. */ | |
2020 | if (is_new_name (def)) | |
2021 | register_new_update_set (def, names_replaced_by (def)); | |
2022 | ||
2023 | /* If DEF is an old name, register DEF as a new | |
2024 | definition for itself. */ | |
2025 | if (is_old_name (def)) | |
2026 | register_new_update_single (def, def); | |
2027 | } | |
2028 | } | |
2029 | ||
2030 | ||
88dbf20f | 2031 | /* Update every variable used in the statement pointed-to by SI. The |
2032 | statement is assumed to be in SSA form already. Names in | |
2033 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
2034 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
2035 | will be registered as a new definition for their corresponding name | |
2036 | in OLD_SSA_NAMES. */ | |
2037 | ||
2038 | static void | |
cd610ee6 | 2039 | rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi) |
88dbf20f | 2040 | { |
88dbf20f | 2041 | use_operand_p use_p; |
2042 | def_operand_p def_p; | |
2043 | ssa_op_iter iter; | |
2044 | ||
88dbf20f | 2045 | /* Only update marked statements. */ |
75a70cf9 | 2046 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
88dbf20f | 2047 | return; |
2048 | ||
2049 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2050 | { | |
2051 | fprintf (dump_file, "Updating SSA information for statement "); | |
75a70cf9 | 2052 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
88dbf20f | 2053 | } |
2054 | ||
2055 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
2056 | symbol is marked for renaming. */ | |
75a70cf9 | 2057 | if (rewrite_uses_p (stmt)) |
9845d120 | 2058 | { |
2059 | if (is_gimple_debug (stmt)) | |
2060 | { | |
2061 | bool failed = false; | |
2062 | ||
2063 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
2064 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
2065 | { | |
2066 | failed = true; | |
2067 | break; | |
2068 | } | |
2069 | ||
2070 | if (failed) | |
2071 | { | |
2072 | /* DOM sometimes threads jumps in such a way that a | |
2073 | debug stmt ends up referencing a SSA variable that no | |
2074 | longer dominates the debug stmt, but such that all | |
2075 | incoming definitions refer to the same definition in | |
2076 | an earlier dominator. We could try to recover that | |
2077 | definition somehow, but this will have to do for now. | |
2078 | ||
2079 | Introducing a default definition, which is what | |
2080 | maybe_replace_use() would do in such cases, may | |
2081 | modify code generation, for the otherwise-unused | |
2082 | default definition would never go away, modifying SSA | |
2083 | version numbers all over. */ | |
2084 | gimple_debug_bind_reset_value (stmt); | |
2085 | update_stmt (stmt); | |
2086 | } | |
2087 | } | |
2088 | else | |
2089 | { | |
2090 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
2091 | maybe_replace_use (use_p); | |
2092 | } | |
2093 | } | |
88dbf20f | 2094 | |
2095 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
2096 | Also register definitions for names whose underlying symbol is | |
2097 | marked for renaming. */ | |
75a70cf9 | 2098 | if (register_defs_p (stmt)) |
dd277d48 | 2099 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
cd610ee6 | 2100 | maybe_register_def (def_p, stmt, gsi); |
88dbf20f | 2101 | } |
2102 | ||
2103 | ||
2104 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
2105 | every PHI node found, check if any of its arguments is in | |
2106 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
2107 | definition, replace it. */ | |
2108 | ||
2109 | static void | |
6bf320fb | 2110 | rewrite_update_phi_arguments (basic_block bb) |
88dbf20f | 2111 | { |
2112 | edge e; | |
2113 | edge_iterator ei; | |
70630fcd | 2114 | unsigned i; |
88dbf20f | 2115 | |
2116 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2117 | { | |
75a70cf9 | 2118 | gimple phi; |
2119 | gimple_vec phis; | |
88dbf20f | 2120 | |
70630fcd | 2121 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
2122 | continue; | |
48e1416a | 2123 | |
75a70cf9 | 2124 | phis = VEC_index (gimple_vec, phis_to_rewrite, e->dest->index); |
48148244 | 2125 | FOR_EACH_VEC_ELT (gimple, phis, i, phi) |
88dbf20f | 2126 | { |
efbcb6de | 2127 | tree arg, lhs_sym, reaching_def = NULL; |
88dbf20f | 2128 | use_operand_p arg_p; |
2129 | ||
75a70cf9 | 2130 | gcc_assert (rewrite_uses_p (phi)); |
88dbf20f | 2131 | |
2132 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2133 | arg = USE_FROM_PTR (arg_p); | |
2134 | ||
2135 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2136 | continue; | |
2137 | ||
75a70cf9 | 2138 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
4fb5e5ca | 2139 | |
88dbf20f | 2140 | if (arg == NULL_TREE) |
2141 | { | |
2142 | /* When updating a PHI node for a recently introduced | |
2143 | symbol we may find NULL arguments. That's why we | |
2144 | take the symbol from the LHS of the PHI node. */ | |
efbcb6de | 2145 | reaching_def = get_reaching_def (lhs_sym); |
2146 | ||
88dbf20f | 2147 | } |
2148 | else | |
2149 | { | |
2150 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2151 | ||
2152 | if (symbol_marked_for_renaming (sym)) | |
efbcb6de | 2153 | reaching_def = get_reaching_def (sym); |
88dbf20f | 2154 | else if (is_old_name (arg)) |
efbcb6de | 2155 | reaching_def = get_reaching_def (arg); |
2156 | } | |
2157 | ||
2158 | /* Update the argument if there is a reaching def. */ | |
2159 | if (reaching_def) | |
2160 | { | |
2161 | gimple stmt; | |
2162 | source_location locus; | |
2163 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2164 | ||
2165 | SET_USE (arg_p, reaching_def); | |
2166 | stmt = SSA_NAME_DEF_STMT (reaching_def); | |
2167 | ||
48e1416a | 2168 | /* Single element PHI nodes behave like copies, so get the |
efbcb6de | 2169 | location from the phi argument. */ |
48e1416a | 2170 | if (gimple_code (stmt) == GIMPLE_PHI && |
efbcb6de | 2171 | gimple_phi_num_args (stmt) == 1) |
2172 | locus = gimple_phi_arg_location (stmt, 0); | |
2173 | else | |
2174 | locus = gimple_location (stmt); | |
2175 | ||
2176 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
88dbf20f | 2177 | } |
2178 | ||
efbcb6de | 2179 | |
88dbf20f | 2180 | if (e->flags & EDGE_ABNORMAL) |
2181 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2182 | } | |
2183 | } | |
2184 | } | |
2185 | ||
2186 | ||
6bf320fb | 2187 | /* Initialization of block data structures for the incremental SSA |
2188 | update pass. Create a block local stack of reaching definitions | |
2189 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2190 | new definitions for every PHI node in the block. */ | |
2191 | ||
2192 | static void | |
2193 | rewrite_update_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2194 | basic_block bb) | |
2195 | { | |
6bf320fb | 2196 | bool is_abnormal_phi; |
2197 | gimple_stmt_iterator gsi; | |
2198 | ||
2199 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
0ffbb1b6 | 2200 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
6bf320fb | 2201 | bb->index); |
2202 | ||
2203 | /* Mark the unwind point for this block. */ | |
2204 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
2205 | ||
2206 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
2207 | return; | |
2208 | ||
2209 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2210 | edge. */ | |
f1047120 | 2211 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
6bf320fb | 2212 | |
2213 | /* If any of the PHI nodes is a replacement for a name in | |
2214 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2215 | register it as a new definition for its corresponding name. Also | |
2216 | register definitions for names whose underlying symbols are | |
2217 | marked for renaming. */ | |
2218 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2219 | { | |
2220 | tree lhs, lhs_sym; | |
2221 | gimple phi = gsi_stmt (gsi); | |
2222 | ||
2223 | if (!register_defs_p (phi)) | |
2224 | continue; | |
48e1416a | 2225 | |
6bf320fb | 2226 | lhs = gimple_phi_result (phi); |
2227 | lhs_sym = SSA_NAME_VAR (lhs); | |
2228 | ||
2229 | if (symbol_marked_for_renaming (lhs_sym)) | |
2230 | register_new_update_single (lhs, lhs_sym); | |
2231 | else | |
2232 | { | |
2233 | ||
2234 | /* If LHS is a new name, register a new definition for all | |
2235 | the names replaced by LHS. */ | |
2236 | if (is_new_name (lhs)) | |
2237 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
48e1416a | 2238 | |
6bf320fb | 2239 | /* If LHS is an OLD name, register it as a new definition |
2240 | for itself. */ | |
2241 | if (is_old_name (lhs)) | |
2242 | register_new_update_single (lhs, lhs); | |
2243 | } | |
2244 | ||
2245 | if (is_abnormal_phi) | |
2246 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2247 | } | |
2248 | ||
2249 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
2250 | if (TEST_BIT (interesting_blocks, bb->index)) | |
cd610ee6 | 2251 | { |
2252 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); | |
6bf320fb | 2253 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
cd610ee6 | 2254 | rewrite_update_stmt (gsi_stmt (gsi), gsi); |
2255 | } | |
6bf320fb | 2256 | |
2257 | /* Step 3. Update PHI nodes. */ | |
2258 | rewrite_update_phi_arguments (bb); | |
2259 | } | |
2260 | ||
2261 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2262 | the current reaching definition of every name re-written in BB to | |
2263 | the original reaching definition before visiting BB. This | |
2264 | unwinding must be done in the opposite order to what is done in | |
2265 | register_new_update_set. */ | |
2266 | ||
2267 | static void | |
2268 | rewrite_update_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2269 | basic_block bb ATTRIBUTE_UNUSED) | |
2270 | { | |
2271 | while (VEC_length (tree, block_defs_stack) > 0) | |
2272 | { | |
2273 | tree var = VEC_pop (tree, block_defs_stack); | |
2274 | tree saved_def; | |
48e1416a | 2275 | |
6bf320fb | 2276 | /* NULL indicates the unwind stop point for this block (see |
2277 | rewrite_update_enter_block). */ | |
2278 | if (var == NULL) | |
2279 | return; | |
2280 | ||
2281 | saved_def = VEC_pop (tree, block_defs_stack); | |
2282 | set_current_def (var, saved_def); | |
2283 | } | |
2284 | } | |
2285 | ||
2286 | ||
88dbf20f | 2287 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
48e1416a | 2288 | form. |
88dbf20f | 2289 | |
2290 | ENTRY indicates the block where to start. Every block dominated by | |
2291 | ENTRY will be rewritten. | |
2292 | ||
2293 | WHAT indicates what actions will be taken by the renamer (see enum | |
2294 | rewrite_mode). | |
2295 | ||
2296 | BLOCKS are the set of interesting blocks for the dominator walker | |
2297 | to process. If this set is NULL, then all the nodes dominated | |
2298 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2299 | are not present in BLOCKS are ignored. */ | |
2300 | ||
2301 | static void | |
6bf320fb | 2302 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
88dbf20f | 2303 | { |
2304 | struct dom_walk_data walk_data; | |
48e1416a | 2305 | |
88dbf20f | 2306 | /* Rewrite all the basic blocks in the program. */ |
2307 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2308 | ||
2309 | /* Setup callbacks for the generic dominator tree walker. */ | |
2310 | memset (&walk_data, 0, sizeof (walk_data)); | |
2311 | ||
2312 | walk_data.dom_direction = CDI_DOMINATORS; | |
88dbf20f | 2313 | |
2314 | if (what == REWRITE_ALL) | |
6bf320fb | 2315 | { |
2316 | walk_data.before_dom_children = rewrite_enter_block; | |
2317 | walk_data.after_dom_children = rewrite_leave_block; | |
2318 | } | |
88dbf20f | 2319 | else if (what == REWRITE_UPDATE) |
6bf320fb | 2320 | { |
2321 | walk_data.before_dom_children = rewrite_update_enter_block; | |
2322 | walk_data.after_dom_children = rewrite_update_leave_block; | |
2323 | } | |
88dbf20f | 2324 | else |
2325 | gcc_unreachable (); | |
2326 | ||
046bfc77 | 2327 | block_defs_stack = VEC_alloc (tree, heap, 10); |
88dbf20f | 2328 | |
2329 | /* Initialize the dominator walker. */ | |
2330 | init_walk_dominator_tree (&walk_data); | |
2331 | ||
2332 | /* Recursively walk the dominator tree rewriting each statement in | |
2333 | each basic block. */ | |
2334 | walk_dominator_tree (&walk_data, entry); | |
2335 | ||
2336 | /* Finalize the dominator walker. */ | |
2337 | fini_walk_dominator_tree (&walk_data); | |
2338 | ||
2339 | /* Debugging dumps. */ | |
2340 | if (dump_file && (dump_flags & TDF_STATS)) | |
2341 | { | |
2342 | dump_dfa_stats (dump_file); | |
2343 | if (def_blocks) | |
2344 | dump_tree_ssa_stats (dump_file); | |
2345 | } | |
48e1416a | 2346 | |
046bfc77 | 2347 | VEC_free (tree, heap, block_defs_stack); |
88dbf20f | 2348 | |
2349 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2350 | } | |
2351 | ||
2352 | ||
6bf320fb | 2353 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2354 | at the start of each block, and call mark_def_sites for each statement. */ | |
4ee9c684 | 2355 | |
f3d9a16c | 2356 | static void |
6bf320fb | 2357 | mark_def_sites_block (struct dom_walk_data *walk_data, basic_block bb) |
f3d9a16c | 2358 | { |
4fb5e5ca | 2359 | struct mark_def_sites_global_data *gd; |
6bf320fb | 2360 | bitmap kills; |
2361 | gimple_stmt_iterator gsi; | |
2362 | ||
4fb5e5ca | 2363 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; |
6bf320fb | 2364 | kills = gd->kills; |
2365 | ||
2366 | bitmap_clear (kills); | |
2367 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2368 | mark_def_sites (bb, gsi_stmt (gsi), kills); | |
e551bd1a | 2369 | } |
f3d9a16c | 2370 | |
f3d9a16c | 2371 | |
88dbf20f | 2372 | /* Mark the definition site blocks for each variable, so that we know |
2373 | where the variable is actually live. | |
2374 | ||
6bf320fb | 2375 | The INTERESTING_BLOCKS global will be filled in with all the blocks |
2376 | that should be processed by the renamer. It is assumed that the | |
2377 | caller has already initialized and zeroed it. */ | |
f3d9a16c | 2378 | |
88dbf20f | 2379 | static void |
6bf320fb | 2380 | mark_def_site_blocks (void) |
e551bd1a | 2381 | { |
e551bd1a | 2382 | struct dom_walk_data walk_data; |
2383 | struct mark_def_sites_global_data mark_def_sites_global_data; | |
f3d9a16c | 2384 | |
e551bd1a | 2385 | /* Setup callbacks for the generic dominator tree walker to find and |
2386 | mark definition sites. */ | |
e551bd1a | 2387 | walk_data.dom_direction = CDI_DOMINATORS; |
2388 | walk_data.initialize_block_local_data = NULL; | |
6bf320fb | 2389 | walk_data.before_dom_children = mark_def_sites_block; |
2390 | walk_data.after_dom_children = NULL; | |
f3d9a16c | 2391 | |
e551bd1a | 2392 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2393 | large enough to accommodate all the variables referenced in the | |
2394 | function, not just the ones we are renaming. */ | |
2395 | mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); | |
2396 | walk_data.global_data = &mark_def_sites_global_data; | |
4ee9c684 | 2397 | |
e551bd1a | 2398 | /* We do not have any local data. */ |
2399 | walk_data.block_local_data_size = 0; | |
2400 | ||
2401 | /* Initialize the dominator walker. */ | |
2402 | init_walk_dominator_tree (&walk_data); | |
2403 | ||
2404 | /* Recursively walk the dominator tree. */ | |
2405 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
2406 | ||
2407 | /* Finalize the dominator walker. */ | |
2408 | fini_walk_dominator_tree (&walk_data); | |
2409 | ||
2410 | /* We no longer need this bitmap, clear and free it. */ | |
2411 | BITMAP_FREE (mark_def_sites_global_data.kills); | |
4ee9c684 | 2412 | } |
2413 | ||
4ee9c684 | 2414 | |
4fb5e5ca | 2415 | /* Initialize internal data needed during renaming. */ |
2416 | ||
2417 | static void | |
2418 | init_ssa_renamer (void) | |
2419 | { | |
2420 | tree var; | |
2421 | referenced_var_iterator rvi; | |
2422 | ||
2423 | cfun->gimple_df->in_ssa_p = false; | |
2424 | ||
2425 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
2426 | gcc_assert (def_blocks == NULL); | |
2427 | def_blocks = htab_create (num_referenced_vars, def_blocks_hash, | |
2428 | def_blocks_eq, def_blocks_free); | |
2429 | ||
a23e00ae | 2430 | FOR_EACH_REFERENCED_VAR (cfun, var, rvi) |
4fb5e5ca | 2431 | set_current_def (var, NULL_TREE); |
2432 | } | |
2433 | ||
2434 | ||
2435 | /* Deallocate internal data structures used by the renamer. */ | |
2436 | ||
2437 | static void | |
2438 | fini_ssa_renamer (void) | |
2439 | { | |
2440 | if (def_blocks) | |
2441 | { | |
2442 | htab_delete (def_blocks); | |
2443 | def_blocks = NULL; | |
2444 | } | |
2445 | ||
2446 | cfun->gimple_df->in_ssa_p = true; | |
2447 | } | |
2448 | ||
e551bd1a | 2449 | /* Main entry point into the SSA builder. The renaming process |
88dbf20f | 2450 | proceeds in four main phases: |
4ee9c684 | 2451 | |
88dbf20f | 2452 | 1- Compute dominance frontier and immediate dominators, needed to |
2453 | insert PHI nodes and rename the function in dominator tree | |
2454 | order. | |
4ee9c684 | 2455 | |
88dbf20f | 2456 | 2- Find and mark all the blocks that define variables |
e551bd1a | 2457 | (mark_def_site_blocks). |
4ee9c684 | 2458 | |
88dbf20f | 2459 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
4ee9c684 | 2460 | |
88dbf20f | 2461 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
4ee9c684 | 2462 | |
21bdfe89 | 2463 | Steps 3 and 4 are done using the dominator tree walker |
88dbf20f | 2464 | (walk_dominator_tree). */ |
e551bd1a | 2465 | |
2a1990e9 | 2466 | static unsigned int |
88dbf20f | 2467 | rewrite_into_ssa (void) |
4ee9c684 | 2468 | { |
8a2980be | 2469 | bitmap_head *dfs; |
e551bd1a | 2470 | basic_block bb; |
48e1416a | 2471 | |
88dbf20f | 2472 | /* Initialize operand data structures. */ |
5084b2e4 | 2473 | init_ssa_operands (cfun); |
4ee9c684 | 2474 | |
4fb5e5ca | 2475 | /* Initialize internal data needed by the renamer. */ |
2476 | init_ssa_renamer (); | |
2477 | ||
88dbf20f | 2478 | /* Initialize the set of interesting blocks. The callback |
2479 | mark_def_sites will add to this set those blocks that the renamer | |
2480 | should process. */ | |
2481 | interesting_blocks = sbitmap_alloc (last_basic_block); | |
2482 | sbitmap_zero (interesting_blocks); | |
4ee9c684 | 2483 | |
71797bf6 | 2484 | /* Initialize dominance frontier. */ |
8a2980be | 2485 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
e551bd1a | 2486 | FOR_EACH_BB (bb) |
8a2980be | 2487 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
4ee9c684 | 2488 | |
88dbf20f | 2489 | /* 1- Compute dominance frontiers. */ |
2490 | calculate_dominance_info (CDI_DOMINATORS); | |
e551bd1a | 2491 | compute_dominance_frontiers (dfs); |
4ee9c684 | 2492 | |
88dbf20f | 2493 | /* 2- Find and mark definition sites. */ |
6bf320fb | 2494 | mark_def_site_blocks (); |
88dbf20f | 2495 | |
2496 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
095dcfa3 | 2497 | insert_phi_nodes (dfs); |
4ee9c684 | 2498 | |
88dbf20f | 2499 | /* 4- Rename all the blocks. */ |
6bf320fb | 2500 | rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL); |
4ee9c684 | 2501 | |
e551bd1a | 2502 | /* Free allocated memory. */ |
2503 | FOR_EACH_BB (bb) | |
8a2980be | 2504 | bitmap_clear (&dfs[bb->index]); |
e551bd1a | 2505 | free (dfs); |
4ee9c684 | 2506 | |
acf11b62 | 2507 | sbitmap_free (interesting_blocks); |
2508 | ||
4fb5e5ca | 2509 | fini_ssa_renamer (); |
2510 | ||
2a1990e9 | 2511 | return 0; |
4ee9c684 | 2512 | } |
2513 | ||
2514 | ||
48e1416a | 2515 | struct gimple_opt_pass pass_build_ssa = |
4ee9c684 | 2516 | { |
20099e35 | 2517 | { |
2518 | GIMPLE_PASS, | |
e551bd1a | 2519 | "ssa", /* name */ |
2520 | NULL, /* gate */ | |
88dbf20f | 2521 | rewrite_into_ssa, /* execute */ |
e551bd1a | 2522 | NULL, /* sub */ |
2523 | NULL, /* next */ | |
2524 | 0, /* static_pass_number */ | |
4b366dd3 | 2525 | TV_TREE_SSA_OTHER, /* tv_id */ |
e551bd1a | 2526 | PROP_cfg | PROP_referenced_vars, /* properties_required */ |
2527 | PROP_ssa, /* properties_provided */ | |
2528 | 0, /* properties_destroyed */ | |
2529 | 0, /* todo_flags_start */ | |
771e2890 | 2530 | TODO_update_ssa_only_virtuals |
db22d3cc | 2531 | | TODO_verify_ssa |
20099e35 | 2532 | | TODO_remove_unused_locals /* todo_flags_finish */ |
2533 | } | |
e551bd1a | 2534 | }; |
4ee9c684 | 2535 | |
2536 | ||
88dbf20f | 2537 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2538 | renamer. BLOCKS is the set of blocks that need updating. */ | |
4ee9c684 | 2539 | |
88dbf20f | 2540 | static void |
75a70cf9 | 2541 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
4ee9c684 | 2542 | { |
2920559d | 2543 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
75a70cf9 | 2544 | set_register_defs (stmt, true); |
88dbf20f | 2545 | |
2546 | if (insert_phi_p) | |
2547 | { | |
75a70cf9 | 2548 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
88dbf20f | 2549 | |
88dbf20f | 2550 | set_def_block (var, bb, is_phi_p); |
2551 | ||
2552 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2553 | site for both itself and all the old names replaced by it. */ | |
2554 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2555 | { | |
2556 | bitmap_iterator bi; | |
2557 | unsigned i; | |
2558 | bitmap set = names_replaced_by (var); | |
2559 | if (set) | |
2560 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2561 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2562 | } | |
2563 | } | |
2564 | } | |
2565 | ||
2566 | ||
2567 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2568 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
2920559d | 2569 | nodes. */ |
88dbf20f | 2570 | |
2571 | static inline void | |
75a70cf9 | 2572 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
88dbf20f | 2573 | { |
75a70cf9 | 2574 | basic_block def_bb = gimple_bb (stmt); |
70630fcd | 2575 | |
2920559d | 2576 | mark_block_for_update (def_bb); |
2577 | mark_block_for_update (bb); | |
2578 | ||
75a70cf9 | 2579 | if (gimple_code (stmt) == GIMPLE_PHI) |
70630fcd | 2580 | mark_phi_for_rewrite (def_bb, stmt); |
2581 | else | |
9845d120 | 2582 | { |
2583 | set_rewrite_uses (stmt, true); | |
2584 | ||
2585 | if (is_gimple_debug (stmt)) | |
2586 | return; | |
2587 | } | |
88dbf20f | 2588 | |
2589 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2590 | to BB. Note that we cannot just use the block holding VAR's | |
2591 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2592 | it will have several definitions (itself and all the names that | |
2593 | replace it). */ | |
2594 | if (insert_phi_p) | |
2595 | { | |
095dcfa3 | 2596 | struct def_blocks_d *db_p = get_def_blocks_for (var); |
88dbf20f | 2597 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2598 | set_livein_block (var, bb); | |
2599 | } | |
2600 | } | |
2601 | ||
2602 | ||
88dbf20f | 2603 | /* Do a dominator walk starting at BB processing statements that |
095dcfa3 | 2604 | reference symbols in SYMS_TO_RENAME. This is very similar to |
2605 | mark_def_sites, but the scan handles statements whose operands may | |
2920559d | 2606 | already be SSA names. |
88dbf20f | 2607 | |
095dcfa3 | 2608 | If INSERT_PHI_P is true, mark those uses as live in the |
2609 | corresponding block. This is later used by the PHI placement | |
4fb5e5ca | 2610 | algorithm to make PHI pruning decisions. |
2611 | ||
2612 | FIXME. Most of this would be unnecessary if we could associate a | |
2613 | symbol to all the SSA names that reference it. But that | |
2614 | sounds like it would be expensive to maintain. Still, it | |
2615 | would be interesting to see if it makes better sense to do | |
2616 | that. */ | |
88dbf20f | 2617 | |
2618 | static void | |
2920559d | 2619 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
88dbf20f | 2620 | { |
2621 | basic_block son; | |
75a70cf9 | 2622 | gimple_stmt_iterator si; |
f50cf978 | 2623 | edge e; |
2624 | edge_iterator ei; | |
88dbf20f | 2625 | |
2920559d | 2626 | mark_block_for_update (bb); |
2627 | ||
88dbf20f | 2628 | /* Process PHI nodes marking interesting those that define or use |
095dcfa3 | 2629 | the symbols that we are interested in. */ |
75a70cf9 | 2630 | for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) |
88dbf20f | 2631 | { |
75a70cf9 | 2632 | gimple phi = gsi_stmt (si); |
2633 | tree lhs_sym, lhs = gimple_phi_result (phi); | |
88dbf20f | 2634 | |
88dbf20f | 2635 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
2636 | ||
f50cf978 | 2637 | if (!symbol_marked_for_renaming (lhs_sym)) |
2638 | continue; | |
75a70cf9 | 2639 | |
f50cf978 | 2640 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2641 | ||
2642 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2643 | to process the arguments of the phi nodes of the successor edges of | |
2644 | BB at the end of prepare_block_for_update, however, that turns out | |
2645 | to be significantly more expensive. Doing it here is conservatively | |
2646 | correct -- it may only cause us to believe a value to be live in a | |
2647 | block that also contains its definition, and thus insert a few more | |
2648 | phi nodes for it. */ | |
2649 | FOR_EACH_EDGE (e, ei, bb->preds) | |
75a70cf9 | 2650 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
88dbf20f | 2651 | } |
2652 | ||
2653 | /* Process the statements. */ | |
75a70cf9 | 2654 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
88dbf20f | 2655 | { |
75a70cf9 | 2656 | gimple stmt; |
88dbf20f | 2657 | ssa_op_iter i; |
2658 | use_operand_p use_p; | |
2659 | def_operand_p def_p; | |
48e1416a | 2660 | |
75a70cf9 | 2661 | stmt = gsi_stmt (si); |
88dbf20f | 2662 | |
4fb5e5ca | 2663 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) |
88dbf20f | 2664 | { |
2665 | tree use = USE_FROM_PTR (use_p); | |
2666 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
095dcfa3 | 2667 | if (symbol_marked_for_renaming (sym)) |
4fb5e5ca | 2668 | mark_use_interesting (sym, stmt, bb, insert_phi_p); |
88dbf20f | 2669 | } |
2670 | ||
4fb5e5ca | 2671 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_ALL_DEFS) |
88dbf20f | 2672 | { |
2673 | tree def = DEF_FROM_PTR (def_p); | |
2674 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
88dbf20f | 2675 | if (symbol_marked_for_renaming (sym)) |
4fb5e5ca | 2676 | mark_def_interesting (sym, stmt, bb, insert_phi_p); |
88dbf20f | 2677 | } |
2678 | } | |
2679 | ||
2680 | /* Now visit all the blocks dominated by BB. */ | |
095dcfa3 | 2681 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
4fb5e5ca | 2682 | son; |
2683 | son = next_dom_son (CDI_DOMINATORS, son)) | |
2920559d | 2684 | prepare_block_for_update (son, insert_phi_p); |
095dcfa3 | 2685 | } |
2686 | ||
2687 | ||
2688 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2689 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2690 | prepare_names_to_update. */ | |
2691 | ||
2692 | static void | |
2920559d | 2693 | prepare_use_sites_for (tree name, bool insert_phi_p) |
095dcfa3 | 2694 | { |
2695 | use_operand_p use_p; | |
2696 | imm_use_iterator iter; | |
2697 | ||
2698 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2699 | { | |
75a70cf9 | 2700 | gimple stmt = USE_STMT (use_p); |
2701 | basic_block bb = gimple_bb (stmt); | |
095dcfa3 | 2702 | |
75a70cf9 | 2703 | if (gimple_code (stmt) == GIMPLE_PHI) |
095dcfa3 | 2704 | { |
f50cf978 | 2705 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
75a70cf9 | 2706 | edge e = gimple_phi_arg_edge (stmt, ix); |
f50cf978 | 2707 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
095dcfa3 | 2708 | } |
2709 | else | |
2710 | { | |
2711 | /* For regular statements, mark this as an interesting use | |
2712 | for NAME. */ | |
2920559d | 2713 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
095dcfa3 | 2714 | } |
2715 | } | |
88dbf20f | 2716 | } |
2717 | ||
2718 | ||
095dcfa3 | 2719 | /* Helper for prepare_names_to_update. Mark the definition site for |
2720 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2721 | prepare_names_to_update. */ | |
88dbf20f | 2722 | |
2723 | static void | |
2920559d | 2724 | prepare_def_site_for (tree name, bool insert_phi_p) |
88dbf20f | 2725 | { |
75a70cf9 | 2726 | gimple stmt; |
88dbf20f | 2727 | basic_block bb; |
2728 | ||
88dbf20f | 2729 | gcc_assert (names_to_release == NULL |
2730 | || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name))); | |
2731 | ||
2732 | stmt = SSA_NAME_DEF_STMT (name); | |
75a70cf9 | 2733 | bb = gimple_bb (stmt); |
88dbf20f | 2734 | if (bb) |
2735 | { | |
2736 | gcc_assert (bb->index < last_basic_block); | |
2920559d | 2737 | mark_block_for_update (bb); |
2738 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
88dbf20f | 2739 | } |
2740 | } | |
2741 | ||
2742 | ||
095dcfa3 | 2743 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
2920559d | 2744 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2745 | PHI nodes for newly created names. */ | |
88dbf20f | 2746 | |
2747 | static void | |
2920559d | 2748 | prepare_names_to_update (bool insert_phi_p) |
88dbf20f | 2749 | { |
86c1585a | 2750 | unsigned i = 0; |
88dbf20f | 2751 | bitmap_iterator bi; |
3e790786 | 2752 | sbitmap_iterator sbi; |
88dbf20f | 2753 | |
2754 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2755 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2756 | defining basic block (which most likely doesn't exist). Notice | |
2757 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2758 | want to replace existing instances. */ | |
2759 | if (names_to_release) | |
2760 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2761 | RESET_BIT (new_ssa_names, i); | |
2762 | ||
095dcfa3 | 2763 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2764 | names may be considered to be live-in on blocks that contain | |
2765 | definitions for their replacements. */ | |
3e790786 | 2766 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
2920559d | 2767 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
095dcfa3 | 2768 | |
88dbf20f | 2769 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2770 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
3e790786 | 2771 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
095dcfa3 | 2772 | { |
2773 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
2920559d | 2774 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2775 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
3e790786 | 2776 | } |
88dbf20f | 2777 | } |
2778 | ||
2779 | ||
2780 | /* Dump all the names replaced by NAME to FILE. */ | |
2781 | ||
2782 | void | |
2783 | dump_names_replaced_by (FILE *file, tree name) | |
2784 | { | |
2785 | unsigned i; | |
2786 | bitmap old_set; | |
2787 | bitmap_iterator bi; | |
2788 | ||
2789 | print_generic_expr (file, name, 0); | |
2790 | fprintf (file, " -> { "); | |
2791 | ||
2792 | old_set = names_replaced_by (name); | |
2793 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2794 | { | |
2795 | print_generic_expr (file, ssa_name (i), 0); | |
2796 | fprintf (file, " "); | |
2797 | } | |
2798 | ||
2799 | fprintf (file, "}\n"); | |
2800 | } | |
2801 | ||
2802 | ||
2803 | /* Dump all the names replaced by NAME to stderr. */ | |
2804 | ||
4b987fac | 2805 | DEBUG_FUNCTION void |
88dbf20f | 2806 | debug_names_replaced_by (tree name) |
2807 | { | |
2808 | dump_names_replaced_by (stderr, name); | |
2809 | } | |
2810 | ||
2811 | ||
095dcfa3 | 2812 | /* Dump SSA update information to FILE. */ |
88dbf20f | 2813 | |
2814 | void | |
095dcfa3 | 2815 | dump_update_ssa (FILE *file) |
88dbf20f | 2816 | { |
86c1585a | 2817 | unsigned i = 0; |
88dbf20f | 2818 | bitmap_iterator bi; |
2819 | ||
dd277d48 | 2820 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 2821 | return; |
2822 | ||
2823 | if (new_ssa_names && sbitmap_first_set_bit (new_ssa_names) >= 0) | |
2824 | { | |
3e790786 | 2825 | sbitmap_iterator sbi; |
2826 | ||
88dbf20f | 2827 | fprintf (file, "\nSSA replacement table\n"); |
2828 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2829 | "O_1, ..., O_j\n\n"); | |
2830 | ||
3e790786 | 2831 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
2832 | dump_names_replaced_by (file, ssa_name (i)); | |
095dcfa3 | 2833 | |
2834 | fprintf (file, "\n"); | |
2835 | fprintf (file, "Number of virtual NEW -> OLD mappings: %7u\n", | |
2836 | update_ssa_stats.num_virtual_mappings); | |
2837 | fprintf (file, "Number of real NEW -> OLD mappings: %7u\n", | |
2838 | update_ssa_stats.num_total_mappings | |
2839 | - update_ssa_stats.num_virtual_mappings); | |
2840 | fprintf (file, "Number of total NEW -> OLD mappings: %7u\n", | |
2841 | update_ssa_stats.num_total_mappings); | |
2842 | ||
2843 | fprintf (file, "\nNumber of virtual symbols: %u\n", | |
2844 | update_ssa_stats.num_virtual_symbols); | |
88dbf20f | 2845 | } |
2846 | ||
dd277d48 | 2847 | if (!bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
88dbf20f | 2848 | { |
0ffbb1b6 | 2849 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
dd277d48 | 2850 | dump_decl_set (file, SYMS_TO_RENAME (cfun)); |
2851 | fprintf (file, "\n"); | |
88dbf20f | 2852 | } |
2853 | ||
88dbf20f | 2854 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2855 | { | |
0ffbb1b6 | 2856 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
88dbf20f | 2857 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2858 | { | |
2859 | print_generic_expr (file, ssa_name (i), 0); | |
2860 | fprintf (file, " "); | |
2861 | } | |
0ffbb1b6 | 2862 | fprintf (file, "\n"); |
88dbf20f | 2863 | } |
88dbf20f | 2864 | } |
2865 | ||
2866 | ||
095dcfa3 | 2867 | /* Dump SSA update information to stderr. */ |
88dbf20f | 2868 | |
4b987fac | 2869 | DEBUG_FUNCTION void |
095dcfa3 | 2870 | debug_update_ssa (void) |
88dbf20f | 2871 | { |
095dcfa3 | 2872 | dump_update_ssa (stderr); |
88dbf20f | 2873 | } |
2874 | ||
2875 | ||
2876 | /* Initialize data structures used for incremental SSA updates. */ | |
2877 | ||
2878 | static void | |
dd277d48 | 2879 | init_update_ssa (struct function *fn) |
88dbf20f | 2880 | { |
095dcfa3 | 2881 | /* Reserve more space than the current number of names. The calls to |
88dbf20f | 2882 | add_new_name_mapping are typically done after creating new SSA |
2883 | names, so we'll need to reallocate these arrays. */ | |
2884 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2885 | sbitmap_zero (old_ssa_names); | |
2886 | ||
2887 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2888 | sbitmap_zero (new_ssa_names); | |
2889 | ||
2890 | repl_tbl = htab_create (20, repl_map_hash, repl_map_eq, repl_map_free); | |
88dbf20f | 2891 | names_to_release = NULL; |
095dcfa3 | 2892 | memset (&update_ssa_stats, 0, sizeof (update_ssa_stats)); |
2893 | update_ssa_stats.virtual_symbols = BITMAP_ALLOC (NULL); | |
dd277d48 | 2894 | update_ssa_initialized_fn = fn; |
88dbf20f | 2895 | } |
2896 | ||
2897 | ||
2898 | /* Deallocate data structures used for incremental SSA updates. */ | |
2899 | ||
095dcfa3 | 2900 | void |
88dbf20f | 2901 | delete_update_ssa (void) |
2902 | { | |
2903 | unsigned i; | |
2904 | bitmap_iterator bi; | |
2905 | ||
2906 | sbitmap_free (old_ssa_names); | |
2907 | old_ssa_names = NULL; | |
2908 | ||
2909 | sbitmap_free (new_ssa_names); | |
2910 | new_ssa_names = NULL; | |
2911 | ||
2912 | htab_delete (repl_tbl); | |
2913 | repl_tbl = NULL; | |
2914 | ||
dd277d48 | 2915 | bitmap_clear (SYMS_TO_RENAME (update_ssa_initialized_fn)); |
095dcfa3 | 2916 | BITMAP_FREE (update_ssa_stats.virtual_symbols); |
88dbf20f | 2917 | |
2918 | if (names_to_release) | |
2919 | { | |
2920 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2921 | release_ssa_name (ssa_name (i)); | |
2922 | BITMAP_FREE (names_to_release); | |
2923 | } | |
2924 | ||
2920559d | 2925 | clear_ssa_name_info (); |
4fb5e5ca | 2926 | |
2927 | fini_ssa_renamer (); | |
2928 | ||
2929 | if (blocks_with_phis_to_rewrite) | |
2930 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2931 | { | |
75a70cf9 | 2932 | gimple_vec phis = VEC_index (gimple_vec, phis_to_rewrite, i); |
4fb5e5ca | 2933 | |
75a70cf9 | 2934 | VEC_free (gimple, heap, phis); |
2935 | VEC_replace (gimple_vec, phis_to_rewrite, i, NULL); | |
4fb5e5ca | 2936 | } |
2937 | ||
2938 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2939 | BITMAP_FREE (blocks_to_update); | |
dd277d48 | 2940 | update_ssa_initialized_fn = NULL; |
88dbf20f | 2941 | } |
2942 | ||
2943 | ||
2944 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
2945 | operand pointed to by DEF_P with the newly created name. Return | |
2946 | the new name and register the replacement mapping <NEW, OLD> in | |
2947 | update_ssa's tables. */ | |
2948 | ||
2949 | tree | |
75a70cf9 | 2950 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
88dbf20f | 2951 | { |
2952 | tree new_name = duplicate_ssa_name (old_name, stmt); | |
2953 | ||
2954 | SET_DEF (def, new_name); | |
2955 | ||
75a70cf9 | 2956 | if (gimple_code (stmt) == GIMPLE_PHI) |
88dbf20f | 2957 | { |
75a70cf9 | 2958 | basic_block bb = gimple_bb (stmt); |
88dbf20f | 2959 | |
2960 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
f1047120 | 2961 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
88dbf20f | 2962 | } |
2963 | ||
2964 | register_new_name_mapping (new_name, old_name); | |
2965 | ||
2966 | /* For the benefit of passes that will be updating the SSA form on | |
2967 | their own, set the current reaching definition of OLD_NAME to be | |
2968 | NEW_NAME. */ | |
2969 | set_current_def (old_name, new_name); | |
2970 | ||
2971 | return new_name; | |
2972 | } | |
2973 | ||
2974 | ||
2975 | /* Register name NEW to be a replacement for name OLD. This function | |
2976 | must be called for every replacement that should be performed by | |
2977 | update_ssa. */ | |
2978 | ||
2979 | void | |
dd277d48 | 2980 | register_new_name_mapping (tree new_tree, tree old) |
88dbf20f | 2981 | { |
dd277d48 | 2982 | if (!update_ssa_initialized_fn) |
2983 | init_update_ssa (cfun); | |
2984 | ||
2985 | gcc_assert (update_ssa_initialized_fn == cfun); | |
88dbf20f | 2986 | |
dd277d48 | 2987 | add_new_name_mapping (new_tree, old); |
88dbf20f | 2988 | } |
2989 | ||
2990 | ||
2991 | /* Register symbol SYM to be renamed by update_ssa. */ | |
2992 | ||
2993 | void | |
2994 | mark_sym_for_renaming (tree sym) | |
2995 | { | |
dd277d48 | 2996 | bitmap_set_bit (SYMS_TO_RENAME (cfun), DECL_UID (sym)); |
88dbf20f | 2997 | } |
2998 | ||
2999 | ||
3000 | /* Register all the symbols in SET to be renamed by update_ssa. */ | |
3001 | ||
3002 | void | |
3003 | mark_set_for_renaming (bitmap set) | |
3004 | { | |
3005 | bitmap_iterator bi; | |
3006 | unsigned i; | |
3007 | ||
4fb5e5ca | 3008 | if (set == NULL || bitmap_empty_p (set)) |
095dcfa3 | 3009 | return; |
3010 | ||
88dbf20f | 3011 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
4fb5e5ca | 3012 | mark_sym_for_renaming (referenced_var (i)); |
88dbf20f | 3013 | } |
3014 | ||
3015 | ||
dd277d48 | 3016 | /* Return true if there is any work to be done by update_ssa |
3017 | for function FN. */ | |
88dbf20f | 3018 | |
3019 | bool | |
dd277d48 | 3020 | need_ssa_update_p (struct function *fn) |
88dbf20f | 3021 | { |
dd277d48 | 3022 | gcc_assert (fn != NULL); |
3023 | return (update_ssa_initialized_fn == fn | |
3024 | || (fn->gimple_df | |
3025 | && !bitmap_empty_p (SYMS_TO_RENAME (fn)))); | |
88dbf20f | 3026 | } |
3027 | ||
4c64356a | 3028 | /* Return true if SSA name mappings have been registered for SSA updating. */ |
3029 | ||
3030 | bool | |
3031 | name_mappings_registered_p (void) | |
3032 | { | |
dd277d48 | 3033 | if (!update_ssa_initialized_fn) |
3034 | return false; | |
3035 | ||
3036 | gcc_assert (update_ssa_initialized_fn == cfun); | |
3037 | ||
4c64356a | 3038 | return repl_tbl && htab_elements (repl_tbl) > 0; |
3039 | } | |
88dbf20f | 3040 | |
3041 | /* Return true if name N has been registered in the replacement table. */ | |
3042 | ||
3043 | bool | |
75a70cf9 | 3044 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
88dbf20f | 3045 | { |
dd277d48 | 3046 | if (!update_ssa_initialized_fn) |
88dbf20f | 3047 | return false; |
3048 | ||
dd277d48 | 3049 | gcc_assert (update_ssa_initialized_fn == cfun); |
3050 | ||
3051 | return is_new_name (n) || is_old_name (n); | |
88dbf20f | 3052 | } |
3053 | ||
3054 | ||
88dbf20f | 3055 | /* Mark NAME to be released after update_ssa has finished. */ |
3056 | ||
3057 | void | |
3058 | release_ssa_name_after_update_ssa (tree name) | |
3059 | { | |
dd277d48 | 3060 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
88dbf20f | 3061 | |
3062 | if (names_to_release == NULL) | |
3063 | names_to_release = BITMAP_ALLOC (NULL); | |
3064 | ||
3065 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
3066 | } | |
3067 | ||
3068 | ||
3069 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
3070 | frontier information. BLOCKS is the set of blocks to be updated. | |
3071 | ||
3072 | This is slightly different than the regular PHI insertion | |
3073 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
3074 | real names (i.e., GIMPLE registers) are inserted: | |
48e1416a | 3075 | |
88dbf20f | 3076 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
3077 | nodes inside the region affected by the block that defines VAR | |
3078 | and the blocks that define all its replacements. All these | |
095dcfa3 | 3079 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
88dbf20f | 3080 | |
3081 | First, we compute the entry point to the region (ENTRY). This is | |
3082 | given by the nearest common dominator to all the definition | |
3083 | blocks. When computing the iterated dominance frontier (IDF), any | |
3084 | block not strictly dominated by ENTRY is ignored. | |
3085 | ||
3086 | We then call the standard PHI insertion algorithm with the pruned | |
3087 | IDF. | |
3088 | ||
3089 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
3090 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
3091 | ||
3092 | static void | |
8a2980be | 3093 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
88dbf20f | 3094 | unsigned update_flags) |
3095 | { | |
3096 | basic_block entry; | |
3097 | struct def_blocks_d *db; | |
3098 | bitmap idf, pruned_idf; | |
3099 | bitmap_iterator bi; | |
3100 | unsigned i; | |
3101 | ||
88dbf20f | 3102 | if (TREE_CODE (var) == SSA_NAME) |
1b4345f7 | 3103 | gcc_checking_assert (is_old_name (var)); |
88dbf20f | 3104 | else |
1b4345f7 | 3105 | gcc_checking_assert (symbol_marked_for_renaming (var)); |
88dbf20f | 3106 | |
3107 | /* Get all the definition sites for VAR. */ | |
3108 | db = find_def_blocks_for (var); | |
3109 | ||
3110 | /* No need to do anything if there were no definitions to VAR. */ | |
3111 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3112 | return; | |
3113 | ||
3114 | /* Compute the initial iterated dominance frontier. */ | |
4fb5e5ca | 3115 | idf = compute_idf (db->def_blocks, dfs); |
88dbf20f | 3116 | pruned_idf = BITMAP_ALLOC (NULL); |
3117 | ||
3118 | if (TREE_CODE (var) == SSA_NAME) | |
3119 | { | |
3120 | if (update_flags == TODO_update_ssa) | |
3121 | { | |
3122 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3123 | only interested in IDF blocks dominated by the nearest | |
3124 | common dominator of all the definition blocks. */ | |
3125 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3126 | db->def_blocks); | |
88dbf20f | 3127 | if (entry != ENTRY_BLOCK_PTR) |
3128 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) | |
3129 | if (BASIC_BLOCK (i) != entry | |
3130 | && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) | |
3131 | bitmap_set_bit (pruned_idf, i); | |
3132 | } | |
3133 | else | |
3134 | { | |
3135 | /* Otherwise, do not prune the IDF for VAR. */ | |
3136 | gcc_assert (update_flags == TODO_update_ssa_full_phi); | |
3137 | bitmap_copy (pruned_idf, idf); | |
3138 | } | |
3139 | } | |
3140 | else | |
3141 | { | |
3142 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3143 | for the first time, so we need to compute the full IDF for | |
3144 | it. */ | |
3145 | bitmap_copy (pruned_idf, idf); | |
88dbf20f | 3146 | } |
3147 | ||
3148 | if (!bitmap_empty_p (pruned_idf)) | |
3149 | { | |
3150 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3151 | are included in the region to be updated. The feeding blocks | |
3152 | are important to guarantee that the PHI arguments are renamed | |
3153 | properly. */ | |
4fb5e5ca | 3154 | |
3155 | /* FIXME, this is not needed if we are updating symbols. We are | |
3156 | already starting at the ENTRY block anyway. */ | |
88dbf20f | 3157 | bitmap_ior_into (blocks, pruned_idf); |
3158 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3159 | { | |
3160 | edge e; | |
3161 | edge_iterator ei; | |
3162 | basic_block bb = BASIC_BLOCK (i); | |
3163 | ||
3164 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3165 | if (e->src->index >= 0) | |
3166 | bitmap_set_bit (blocks, e->src->index); | |
3167 | } | |
3168 | ||
3169 | insert_phi_nodes_for (var, pruned_idf, true); | |
3170 | } | |
3171 | ||
3172 | BITMAP_FREE (pruned_idf); | |
3173 | BITMAP_FREE (idf); | |
3174 | } | |
3175 | ||
3176 | ||
095dcfa3 | 3177 | /* Heuristic to determine whether SSA name mappings for virtual names |
3178 | should be discarded and their symbols rewritten from scratch. When | |
3179 | there is a large number of mappings for virtual names, the | |
3180 | insertion of PHI nodes for the old names in the mappings takes | |
3181 | considerable more time than if we inserted PHI nodes for the | |
3182 | symbols instead. | |
3183 | ||
3184 | Currently the heuristic takes these stats into account: | |
3185 | ||
3186 | - Number of mappings for virtual SSA names. | |
3187 | - Number of distinct virtual symbols involved in those mappings. | |
3188 | ||
3189 | If the number of virtual mappings is much larger than the number of | |
3190 | virtual symbols, then it will be faster to compute PHI insertion | |
3191 | spots for the symbols. Even if this involves traversing the whole | |
3192 | CFG, which is what happens when symbols are renamed from scratch. */ | |
3193 | ||
3194 | static bool | |
3195 | switch_virtuals_to_full_rewrite_p (void) | |
3196 | { | |
3197 | if (update_ssa_stats.num_virtual_mappings < (unsigned) MIN_VIRTUAL_MAPPINGS) | |
3198 | return false; | |
3199 | ||
3200 | if (update_ssa_stats.num_virtual_mappings | |
3201 | > (unsigned) VIRTUAL_MAPPINGS_TO_SYMS_RATIO | |
3202 | * update_ssa_stats.num_virtual_symbols) | |
3203 | return true; | |
3204 | ||
3205 | return false; | |
3206 | } | |
3207 | ||
3208 | ||
3209 | /* Remove every virtual mapping and mark all the affected virtual | |
3210 | symbols for renaming. */ | |
3211 | ||
3212 | static void | |
3213 | switch_virtuals_to_full_rewrite (void) | |
3214 | { | |
86c1585a | 3215 | unsigned i = 0; |
3e790786 | 3216 | sbitmap_iterator sbi; |
095dcfa3 | 3217 | |
3218 | if (dump_file) | |
3219 | { | |
3220 | fprintf (dump_file, "\nEnabled virtual name mapping heuristic.\n"); | |
3221 | fprintf (dump_file, "\tNumber of virtual mappings: %7u\n", | |
3222 | update_ssa_stats.num_virtual_mappings); | |
3223 | fprintf (dump_file, "\tNumber of unique virtual symbols: %7u\n", | |
3224 | update_ssa_stats.num_virtual_symbols); | |
3225 | fprintf (dump_file, "Updating FUD-chains from top of CFG will be " | |
3226 | "faster than processing\nthe name mappings.\n\n"); | |
3227 | } | |
3228 | ||
3229 | /* Remove all virtual names from NEW_SSA_NAMES and OLD_SSA_NAMES. | |
3230 | Note that it is not really necessary to remove the mappings from | |
3231 | REPL_TBL, that would only waste time. */ | |
3e790786 | 3232 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
095dcfa3 | 3233 | if (!is_gimple_reg (ssa_name (i))) |
3e790786 | 3234 | RESET_BIT (new_ssa_names, i); |
095dcfa3 | 3235 | |
3e790786 | 3236 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
095dcfa3 | 3237 | if (!is_gimple_reg (ssa_name (i))) |
3e790786 | 3238 | RESET_BIT (old_ssa_names, i); |
095dcfa3 | 3239 | |
4fb5e5ca | 3240 | mark_set_for_renaming (update_ssa_stats.virtual_symbols); |
095dcfa3 | 3241 | } |
3242 | ||
3243 | ||
88dbf20f | 3244 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of |
3245 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3246 | ||
3247 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3248 | NEW_SSA_NAMES are all re-written to be reached by the | |
3249 | appropriate definition from NEW_SSA_NAMES. | |
3250 | ||
3251 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3252 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3253 | ||
3254 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
3255 | calling register_new_name_mapping for every pair of names that the | |
3256 | caller wants to replace. | |
3257 | ||
3258 | The caller identifies the new names that have been inserted and the | |
3259 | names that need to be replaced by calling register_new_name_mapping | |
3260 | for every pair <NEW, OLD>. Note that the function assumes that the | |
3261 | new names have already been inserted in the IL. | |
3262 | ||
3263 | For instance, given the following code: | |
3264 | ||
3265 | 1 L0: | |
3266 | 2 x_1 = PHI (0, x_5) | |
3267 | 3 if (x_1 < 10) | |
3268 | 4 if (x_1 > 7) | |
3269 | 5 y_2 = 0 | |
3270 | 6 else | |
3271 | 7 y_3 = x_1 + x_7 | |
3272 | 8 endif | |
3273 | 9 x_5 = x_1 + 1 | |
3274 | 10 goto L0; | |
3275 | 11 endif | |
3276 | ||
3277 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3278 | ||
3279 | 1 L0: | |
3280 | 2 x_1 = PHI (0, x_5) | |
3281 | 3 if (x_1 < 10) | |
3282 | 4 x_10 = ... | |
3283 | 5 if (x_1 > 7) | |
3284 | 6 y_2 = 0 | |
3285 | 7 else | |
3286 | 8 x_11 = ... | |
3287 | 9 y_3 = x_1 + x_7 | |
3288 | 10 endif | |
3289 | 11 x_5 = x_1 + 1 | |
3290 | 12 goto L0; | |
3291 | 13 endif | |
3292 | ||
3293 | We want to replace all the uses of x_1 with the new definitions of | |
3294 | x_10 and x_11. Note that the only uses that should be replaced are | |
3295 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3296 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3297 | renaming). | |
3298 | ||
3299 | Additionally, we may need to insert a PHI node at line 11 because | |
3300 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3301 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3302 | nodes is optional. They are not strictly necessary to preserve the | |
3303 | SSA form, and depending on what the caller inserted, they may not | |
3304 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3305 | aspects of how update_ssa operates, see the documentation for | |
3306 | TODO_update_ssa*. */ | |
3307 | ||
3308 | void | |
3309 | update_ssa (unsigned update_flags) | |
3310 | { | |
88dbf20f | 3311 | basic_block bb, start_bb; |
3312 | bitmap_iterator bi; | |
86c1585a | 3313 | unsigned i = 0; |
88dbf20f | 3314 | bool insert_phi_p; |
3e790786 | 3315 | sbitmap_iterator sbi; |
88dbf20f | 3316 | |
dd277d48 | 3317 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 3318 | return; |
3319 | ||
3320 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
3321 | ||
0ffbb1b6 | 3322 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3323 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3324 | ||
dd277d48 | 3325 | if (!update_ssa_initialized_fn) |
3326 | init_update_ssa (cfun); | |
3327 | gcc_assert (update_ssa_initialized_fn == cfun); | |
3328 | ||
70630fcd | 3329 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
3330 | if (!phis_to_rewrite) | |
75a70cf9 | 3331 | phis_to_rewrite = VEC_alloc (gimple_vec, heap, last_basic_block); |
2920559d | 3332 | blocks_to_update = BITMAP_ALLOC (NULL); |
70630fcd | 3333 | |
88dbf20f | 3334 | /* Ensure that the dominance information is up-to-date. */ |
3335 | calculate_dominance_info (CDI_DOMINATORS); | |
3336 | ||
3337 | /* Only one update flag should be set. */ | |
3338 | gcc_assert (update_flags == TODO_update_ssa | |
3339 | || update_flags == TODO_update_ssa_no_phi | |
3340 | || update_flags == TODO_update_ssa_full_phi | |
3341 | || update_flags == TODO_update_ssa_only_virtuals); | |
3342 | ||
3343 | /* If we only need to update virtuals, remove all the mappings for | |
095dcfa3 | 3344 | real names before proceeding. The caller is responsible for |
3345 | having dealt with the name mappings before calling update_ssa. */ | |
88dbf20f | 3346 | if (update_flags == TODO_update_ssa_only_virtuals) |
3347 | { | |
3348 | sbitmap_zero (old_ssa_names); | |
3349 | sbitmap_zero (new_ssa_names); | |
3350 | htab_empty (repl_tbl); | |
88dbf20f | 3351 | } |
3352 | ||
095dcfa3 | 3353 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
88dbf20f | 3354 | |
3355 | if (insert_phi_p) | |
3356 | { | |
66d00abf | 3357 | /* If the caller requested PHI nodes to be added, initialize |
3358 | live-in information data structures (DEF_BLOCKS). */ | |
88dbf20f | 3359 | |
3360 | /* For each SSA name N, the DEF_BLOCKS table describes where the | |
3361 | name is defined, which blocks have PHI nodes for N, and which | |
3362 | blocks have uses of N (i.e., N is live-on-entry in those | |
3363 | blocks). */ | |
3364 | def_blocks = htab_create (num_ssa_names, def_blocks_hash, | |
3365 | def_blocks_eq, def_blocks_free); | |
3366 | } | |
3367 | else | |
3368 | { | |
88dbf20f | 3369 | def_blocks = NULL; |
3370 | } | |
3371 | ||
095dcfa3 | 3372 | /* Heuristic to avoid massive slow downs when the replacement |
3373 | mappings include lots of virtual names. */ | |
3374 | if (insert_phi_p && switch_virtuals_to_full_rewrite_p ()) | |
3375 | switch_virtuals_to_full_rewrite (); | |
3376 | ||
3377 | /* If there are names defined in the replacement table, prepare | |
3378 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3379 | OLD_SSA_NAMES. */ | |
3380 | if (sbitmap_first_set_bit (new_ssa_names) >= 0) | |
3381 | { | |
2920559d | 3382 | prepare_names_to_update (insert_phi_p); |
095dcfa3 | 3383 | |
3384 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3385 | removal, and there are no symbols to rename, then there's | |
3386 | nothing else to do. */ | |
3387 | if (sbitmap_first_set_bit (new_ssa_names) < 0 | |
dd277d48 | 3388 | && bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
095dcfa3 | 3389 | goto done; |
3390 | } | |
3391 | ||
3392 | /* Next, determine the block at which to start the renaming process. */ | |
dd277d48 | 3393 | if (!bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
095dcfa3 | 3394 | { |
3395 | /* If we have to rename some symbols from scratch, we need to | |
3396 | start the process at the root of the CFG. FIXME, it should | |
3397 | be possible to determine the nearest block that had a | |
3398 | definition for each of the symbols that are marked for | |
3399 | updating. For now this seems more work than it's worth. */ | |
3400 | start_bb = ENTRY_BLOCK_PTR; | |
3401 | ||
4fb5e5ca | 3402 | /* Traverse the CFG looking for existing definitions and uses of |
3403 | symbols in SYMS_TO_RENAME. Mark interesting blocks and | |
3404 | statements and set local live-in information for the PHI | |
3405 | placement heuristics. */ | |
2920559d | 3406 | prepare_block_for_update (start_bb, insert_phi_p); |
88dbf20f | 3407 | } |
3408 | else | |
095dcfa3 | 3409 | { |
3410 | /* Otherwise, the entry block to the region is the nearest | |
3411 | common dominator for the blocks in BLOCKS. */ | |
2920559d | 3412 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3413 | blocks_to_update); | |
095dcfa3 | 3414 | } |
88dbf20f | 3415 | |
3416 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
095dcfa3 | 3417 | of every block, creating new definitions for names in OLD_SSA_NAMES |
88dbf20f | 3418 | and for symbols in SYMS_TO_RENAME. */ |
3419 | if (insert_phi_p) | |
3420 | { | |
8a2980be | 3421 | bitmap_head *dfs; |
66d00abf | 3422 | |
3423 | /* If the caller requested PHI nodes to be added, compute | |
3424 | dominance frontiers. */ | |
8a2980be | 3425 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
66d00abf | 3426 | FOR_EACH_BB (bb) |
8a2980be | 3427 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
66d00abf | 3428 | compute_dominance_frontiers (dfs); |
3429 | ||
88dbf20f | 3430 | if (sbitmap_first_set_bit (old_ssa_names) >= 0) |
3431 | { | |
3e790786 | 3432 | sbitmap_iterator sbi; |
3433 | ||
095dcfa3 | 3434 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3435 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3436 | will grow while we are traversing it (but it will not | |
3437 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3438 | for traversal. */ | |
88dbf20f | 3439 | sbitmap tmp = sbitmap_alloc (old_ssa_names->n_bits); |
3440 | sbitmap_copy (tmp, old_ssa_names); | |
3e790786 | 3441 | EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i, sbi) |
2920559d | 3442 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
3e790786 | 3443 | update_flags); |
88dbf20f | 3444 | sbitmap_free (tmp); |
3445 | } | |
3446 | ||
dd277d48 | 3447 | EXECUTE_IF_SET_IN_BITMAP (SYMS_TO_RENAME (cfun), 0, i, bi) |
4fb5e5ca | 3448 | insert_updated_phi_nodes_for (referenced_var (i), dfs, blocks_to_update, |
3449 | update_flags); | |
88dbf20f | 3450 | |
66d00abf | 3451 | FOR_EACH_BB (bb) |
8a2980be | 3452 | bitmap_clear (&dfs[bb->index]); |
66d00abf | 3453 | free (dfs); |
3454 | ||
88dbf20f | 3455 | /* Insertion of PHI nodes may have added blocks to the region. |
3456 | We need to re-compute START_BB to include the newly added | |
3457 | blocks. */ | |
3458 | if (start_bb != ENTRY_BLOCK_PTR) | |
2920559d | 3459 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3460 | blocks_to_update); | |
88dbf20f | 3461 | } |
3462 | ||
3463 | /* Reset the current definition for name and symbol before renaming | |
3464 | the sub-graph. */ | |
3e790786 | 3465 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
3466 | set_current_def (ssa_name (i), NULL_TREE); | |
88dbf20f | 3467 | |
dd277d48 | 3468 | EXECUTE_IF_SET_IN_BITMAP (SYMS_TO_RENAME (cfun), 0, i, bi) |
88dbf20f | 3469 | set_current_def (referenced_var (i), NULL_TREE); |
3470 | ||
3471 | /* Now start the renaming process at START_BB. */ | |
6bf320fb | 3472 | interesting_blocks = sbitmap_alloc (last_basic_block); |
3473 | sbitmap_zero (interesting_blocks); | |
2920559d | 3474 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
6bf320fb | 3475 | SET_BIT (interesting_blocks, i); |
88dbf20f | 3476 | |
6bf320fb | 3477 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
88dbf20f | 3478 | |
6bf320fb | 3479 | sbitmap_free (interesting_blocks); |
88dbf20f | 3480 | |
3481 | /* Debugging dumps. */ | |
3482 | if (dump_file) | |
3483 | { | |
3484 | int c; | |
3485 | unsigned i; | |
3486 | ||
095dcfa3 | 3487 | dump_update_ssa (dump_file); |
88dbf20f | 3488 | |
0ffbb1b6 | 3489 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
88dbf20f | 3490 | start_bb->index); |
3491 | ||
3492 | c = 0; | |
2920559d | 3493 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
88dbf20f | 3494 | c++; |
3495 | fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block); | |
0ffbb1b6 | 3496 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
88dbf20f | 3497 | c, PERCENT (c, last_basic_block)); |
3498 | ||
3499 | if (dump_flags & TDF_DETAILS) | |
3500 | { | |
7ef97146 | 3501 | fprintf (dump_file, "Affected blocks:"); |
2920559d | 3502 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
7ef97146 | 3503 | fprintf (dump_file, " %u", i); |
88dbf20f | 3504 | fprintf (dump_file, "\n"); |
3505 | } | |
3506 | ||
3507 | fprintf (dump_file, "\n\n"); | |
3508 | } | |
3509 | ||
3510 | /* Free allocated memory. */ | |
095dcfa3 | 3511 | done: |
88dbf20f | 3512 | delete_update_ssa (); |
3513 | ||
3514 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3515 | } |