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Commit | Line | Data |
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6de9cd9a | 1 | /* Rewrite a program in Normal form into SSA. |
7072a650 | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009 |
9dcd6f09 | 3 | Free Software Foundation, Inc. |
6de9cd9a DN |
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 | |
9dcd6f09 | 10 | the Free Software Foundation; either version 3, or (at your option) |
6de9cd9a DN |
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 | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
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" | |
28 | #include "rtl.h" | |
29 | #include "tm_p.h" | |
30 | #include "langhooks.h" | |
31 | #include "hard-reg-set.h" | |
32 | #include "basic-block.h" | |
33 | #include "output.h" | |
6de9cd9a DN |
34 | #include "expr.h" |
35 | #include "function.h" | |
36 | #include "diagnostic.h" | |
37 | #include "bitmap.h" | |
38 | #include "tree-flow.h" | |
726a989a | 39 | #include "gimple.h" |
6de9cd9a DN |
40 | #include "tree-inline.h" |
41 | #include "varray.h" | |
42 | #include "timevar.h" | |
6de9cd9a DN |
43 | #include "hashtab.h" |
44 | #include "tree-dump.h" | |
45 | #include "tree-pass.h" | |
46 | #include "cfgloop.h" | |
47 | #include "domwalk.h" | |
5f240ec4 | 48 | #include "ggc.h" |
84d65814 | 49 | #include "params.h" |
e3df376d | 50 | #include "vecprim.h" |
6de9cd9a | 51 | |
726a989a | 52 | |
6de9cd9a DN |
53 | /* This file builds the SSA form for a function as described in: |
54 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
55 | Computing Static Single Assignment Form and the Control Dependence | |
56 | Graph. ACM Transactions on Programming Languages and Systems, | |
57 | 13(4):451-490, October 1991. */ | |
58 | ||
6de9cd9a DN |
59 | /* Structure to map a variable VAR to the set of blocks that contain |
60 | definitions for VAR. */ | |
61 | struct def_blocks_d | |
62 | { | |
63 | /* The variable. */ | |
64 | tree var; | |
65 | ||
66 | /* Blocks that contain definitions of VAR. Bit I will be set if the | |
67 | Ith block contains a definition of VAR. */ | |
68 | bitmap def_blocks; | |
69 | ||
7256233c | 70 | /* Blocks that contain a PHI node for VAR. */ |
5f240ec4 ZD |
71 | bitmap phi_blocks; |
72 | ||
6de9cd9a DN |
73 | /* Blocks where VAR is live-on-entry. Similar semantics as |
74 | DEF_BLOCKS. */ | |
75 | bitmap livein_blocks; | |
76 | }; | |
77 | ||
7256233c | 78 | |
6de9cd9a DN |
79 | /* Each entry in DEF_BLOCKS contains an element of type STRUCT |
80 | DEF_BLOCKS_D, mapping a variable VAR to a bitmap describing all the | |
81 | basic blocks where VAR is defined (assigned a new value). It also | |
82 | contains a bitmap of all the blocks where VAR is live-on-entry | |
83 | (i.e., there is a use of VAR in block B without a preceding | |
84 | definition in B). The live-on-entry information is used when | |
85 | computing PHI pruning heuristics. */ | |
86 | static htab_t def_blocks; | |
87 | ||
9fae925b | 88 | /* Stack of trees used to restore the global currdefs to its original |
0bca51f0 DN |
89 | state after completing rewriting of a block and its dominator |
90 | children. Its elements have the following properties: | |
9fae925b | 91 | |
38635499 DN |
92 | - An SSA_NAME (N) indicates that the current definition of the |
93 | underlying variable should be set to the given SSA_NAME. If the | |
94 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
95 | next slot in the stack must be a _DECL node (SYM). In this case, | |
96 | the name N in the previous slot is the current reaching | |
97 | definition for SYM. | |
9fae925b | 98 | |
0bca51f0 DN |
99 | - A _DECL node indicates that the underlying variable has no |
100 | current definition. | |
7256233c | 101 | |
38635499 | 102 | - A NULL node at the top entry is used to mark the last slot |
0bca51f0 | 103 | associated with the current block. */ |
d4e6fecb | 104 | static VEC(tree,heap) *block_defs_stack; |
3a2e4b46 | 105 | |
726a989a | 106 | |
0bca51f0 DN |
107 | /* Set of existing SSA names being replaced by update_ssa. */ |
108 | static sbitmap old_ssa_names; | |
109 | ||
110 | /* Set of new SSA names being added by update_ssa. Note that both | |
111 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
112 | the operations done on them are presence tests. */ | |
113 | static sbitmap new_ssa_names; | |
114 | ||
ccf5c864 | 115 | sbitmap interesting_blocks; |
726a989a | 116 | |
0bca51f0 DN |
117 | /* Set of SSA names that have been marked to be released after they |
118 | were registered in the replacement table. They will be finally | |
119 | released after we finish updating the SSA web. */ | |
120 | static bitmap names_to_release; | |
121 | ||
726a989a | 122 | static VEC(gimple_vec, heap) *phis_to_rewrite; |
2ce79879 ZD |
123 | |
124 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
125 | static bitmap blocks_with_phis_to_rewrite; |
126 | ||
0bca51f0 DN |
127 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
128 | to grow as the callers to register_new_name_mapping will typically | |
129 | create new names on the fly. FIXME. Currently set to 1/3 to avoid | |
130 | frequent reallocations but still need to find a reasonable growth | |
131 | strategy. */ | |
132 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) | |
133 | ||
134 | /* Tuple used to represent replacement mappings. */ | |
135 | struct repl_map_d | |
136 | { | |
137 | tree name; | |
138 | bitmap set; | |
139 | }; | |
140 | ||
726a989a | 141 | |
0bca51f0 DN |
142 | /* NEW -> OLD_SET replacement table. If we are replacing several |
143 | existing SSA names O_1, O_2, ..., O_j with a new name N_i, | |
144 | then REPL_TBL[N_i] = { O_1, O_2, ..., O_j }. */ | |
145 | static htab_t repl_tbl; | |
146 | ||
5006671f RG |
147 | /* The function the SSA updating data structures have been initialized for. |
148 | NULL if they need to be initialized by register_new_name_mapping. */ | |
149 | static struct function *update_ssa_initialized_fn = NULL; | |
0bca51f0 | 150 | |
84d65814 DN |
151 | /* Statistics kept by update_ssa to use in the virtual mapping |
152 | heuristic. If the number of virtual mappings is beyond certain | |
153 | threshold, the updater will switch from using the mappings into | |
154 | renaming the virtual symbols from scratch. In some cases, the | |
155 | large number of name mappings for virtual names causes significant | |
156 | slowdowns in the PHI insertion code. */ | |
157 | struct update_ssa_stats_d | |
158 | { | |
159 | unsigned num_virtual_mappings; | |
160 | unsigned num_total_mappings; | |
161 | bitmap virtual_symbols; | |
162 | unsigned num_virtual_symbols; | |
163 | }; | |
164 | static struct update_ssa_stats_d update_ssa_stats; | |
0bca51f0 | 165 | |
6de9cd9a DN |
166 | /* Global data to attach to the main dominator walk structure. */ |
167 | struct mark_def_sites_global_data | |
168 | { | |
0bca51f0 DN |
169 | /* This bitmap contains the variables which are set before they |
170 | are used in a basic block. */ | |
7d793e36 | 171 | bitmap kills; |
6de9cd9a DN |
172 | }; |
173 | ||
5f240ec4 | 174 | |
0bca51f0 | 175 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
176 | struct ssa_name_info |
177 | { | |
38635499 | 178 | /* The current reaching definition replacing this SSA name. */ |
95dd3097 ZD |
179 | tree current_def; |
180 | ||
5f240ec4 ZD |
181 | /* This field indicates whether or not the variable may need PHI nodes. |
182 | See the enum's definition for more detailed information about the | |
183 | states. */ | |
184 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
185 | ||
95dd3097 | 186 | /* Age of this record (so that info_for_ssa_name table can be cleared |
fa10beec | 187 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields |
95dd3097 ZD |
188 | are assumed to be null. */ |
189 | unsigned age; | |
5f240ec4 | 190 | }; |
6de9cd9a | 191 | |
95dd3097 ZD |
192 | /* The information associated with names. */ |
193 | typedef struct ssa_name_info *ssa_name_info_p; | |
194 | DEF_VEC_P (ssa_name_info_p); | |
195 | DEF_VEC_ALLOC_P (ssa_name_info_p, heap); | |
196 | ||
197 | static VEC(ssa_name_info_p, heap) *info_for_ssa_name; | |
198 | static unsigned current_info_for_ssa_name_age; | |
199 | ||
200 | /* The set of blocks affected by update_ssa. */ | |
95dd3097 | 201 | static bitmap blocks_to_update; |
6de9cd9a | 202 | |
0bca51f0 DN |
203 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
204 | called several times to do different, but related, tasks. | |
205 | Initially, we need it to rename the whole program into SSA form. | |
206 | At other times, we may need it to only rename into SSA newly | |
207 | exposed symbols. Finally, we can also call it to incrementally fix | |
208 | an already built SSA web. */ | |
209 | enum rewrite_mode { | |
210 | /* Convert the whole function into SSA form. */ | |
211 | REWRITE_ALL, | |
212 | ||
213 | /* Incrementally update the SSA web by replacing existing SSA | |
214 | names with new ones. See update_ssa for details. */ | |
215 | REWRITE_UPDATE | |
216 | }; | |
217 | ||
218 | ||
0bca51f0 | 219 | |
7d5f9cc6 | 220 | |
84d65814 DN |
221 | /* Prototypes for debugging functions. */ |
222 | extern void dump_tree_ssa (FILE *); | |
223 | extern void debug_tree_ssa (void); | |
224 | extern void debug_def_blocks (void); | |
225 | extern void dump_tree_ssa_stats (FILE *); | |
226 | extern void debug_tree_ssa_stats (void); | |
38635499 DN |
227 | extern void dump_update_ssa (FILE *); |
228 | extern void debug_update_ssa (void); | |
229 | extern void dump_names_replaced_by (FILE *, tree); | |
230 | extern void debug_names_replaced_by (tree); | |
231 | extern void dump_def_blocks (FILE *); | |
232 | extern void debug_def_blocks (void); | |
233 | extern void dump_defs_stack (FILE *, int); | |
234 | extern void debug_defs_stack (int); | |
235 | extern void dump_currdefs (FILE *); | |
236 | extern void debug_currdefs (void); | |
84d65814 | 237 | |
726a989a RB |
238 | /* Return true if STMT needs to be rewritten. When renaming a subset |
239 | of the variables, not all statements will be processed. This is | |
240 | decided in mark_def_sites. */ | |
241 | ||
242 | static inline bool | |
243 | rewrite_uses_p (gimple stmt) | |
244 | { | |
245 | return gimple_visited_p (stmt); | |
246 | } | |
247 | ||
248 | ||
249 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
250 | ||
251 | static inline void | |
252 | set_rewrite_uses (gimple stmt, bool rewrite_p) | |
253 | { | |
254 | gimple_set_visited (stmt, rewrite_p); | |
255 | } | |
256 | ||
257 | ||
258 | /* Return true if the DEFs created by statement STMT should be | |
259 | registered when marking new definition sites. This is slightly | |
260 | different than rewrite_uses_p: it's used by update_ssa to | |
261 | distinguish statements that need to have both uses and defs | |
262 | processed from those that only need to have their defs processed. | |
263 | Statements that define new SSA names only need to have their defs | |
264 | registered, but they don't need to have their uses renamed. */ | |
265 | ||
266 | static inline bool | |
267 | register_defs_p (gimple stmt) | |
268 | { | |
269 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
270 | } | |
271 | ||
272 | ||
273 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
274 | ||
275 | static inline void | |
276 | set_register_defs (gimple stmt, bool register_defs_p) | |
277 | { | |
278 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
279 | } | |
280 | ||
281 | ||
5f240ec4 ZD |
282 | /* Get the information associated with NAME. */ |
283 | ||
38635499 | 284 | static inline ssa_name_info_p |
5f240ec4 ZD |
285 | get_ssa_name_ann (tree name) |
286 | { | |
95dd3097 ZD |
287 | unsigned ver = SSA_NAME_VERSION (name); |
288 | unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name); | |
289 | struct ssa_name_info *info; | |
290 | ||
291 | if (ver >= len) | |
292 | { | |
293 | unsigned new_len = num_ssa_names; | |
294 | ||
295 | VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name, new_len); | |
296 | while (len++ < new_len) | |
297 | { | |
298 | struct ssa_name_info *info = XCNEW (struct ssa_name_info); | |
299 | info->age = current_info_for_ssa_name_age; | |
300 | VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info); | |
301 | } | |
302 | } | |
303 | ||
304 | info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver); | |
305 | if (info->age < current_info_for_ssa_name_age) | |
306 | { | |
32e8bb8e | 307 | info->need_phi_state = NEED_PHI_STATE_UNKNOWN; |
95dd3097 ZD |
308 | info->current_def = NULL_TREE; |
309 | info->age = current_info_for_ssa_name_age; | |
310 | } | |
5f240ec4 | 311 | |
95dd3097 | 312 | return info; |
5f240ec4 ZD |
313 | } |
314 | ||
38635499 DN |
315 | |
316 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
317 | |
318 | static void | |
319 | clear_ssa_name_info (void) | |
320 | { | |
321 | current_info_for_ssa_name_age++; | |
322 | } | |
7256233c | 323 | |
38635499 DN |
324 | |
325 | /* Get phi_state field for VAR. */ | |
5f240ec4 ZD |
326 | |
327 | static inline enum need_phi_state | |
328 | get_phi_state (tree var) | |
329 | { | |
330 | if (TREE_CODE (var) == SSA_NAME) | |
331 | return get_ssa_name_ann (var)->need_phi_state; | |
332 | else | |
333 | return var_ann (var)->need_phi_state; | |
334 | } | |
335 | ||
7256233c | 336 | |
5f240ec4 ZD |
337 | /* Sets phi_state field for VAR to STATE. */ |
338 | ||
339 | static inline void | |
340 | set_phi_state (tree var, enum need_phi_state state) | |
341 | { | |
342 | if (TREE_CODE (var) == SSA_NAME) | |
343 | get_ssa_name_ann (var)->need_phi_state = state; | |
344 | else | |
345 | var_ann (var)->need_phi_state = state; | |
346 | } | |
347 | ||
7256233c | 348 | |
5f240ec4 ZD |
349 | /* Return the current definition for VAR. */ |
350 | ||
84d65814 | 351 | tree |
5f240ec4 ZD |
352 | get_current_def (tree var) |
353 | { | |
354 | if (TREE_CODE (var) == SSA_NAME) | |
355 | return get_ssa_name_ann (var)->current_def; | |
356 | else | |
357 | return var_ann (var)->current_def; | |
358 | } | |
359 | ||
7256233c | 360 | |
5f240ec4 ZD |
361 | /* Sets current definition of VAR to DEF. */ |
362 | ||
84d65814 | 363 | void |
5f240ec4 ZD |
364 | set_current_def (tree var, tree def) |
365 | { | |
366 | if (TREE_CODE (var) == SSA_NAME) | |
367 | get_ssa_name_ann (var)->current_def = def; | |
368 | else | |
369 | var_ann (var)->current_def = def; | |
370 | } | |
371 | ||
7256233c | 372 | |
fa10beec | 373 | /* Compute global livein information given the set of blocks where |
6de9cd9a DN |
374 | an object is locally live at the start of the block (LIVEIN) |
375 | and the set of blocks where the object is defined (DEF_BLOCKS). | |
376 | ||
377 | Note: This routine augments the existing local livein information | |
378 | to include global livein (i.e., it modifies the underlying bitmap | |
379 | for LIVEIN). */ | |
380 | ||
5f240ec4 | 381 | void |
726a989a | 382 | compute_global_livein (bitmap livein ATTRIBUTE_UNUSED, bitmap def_blocks ATTRIBUTE_UNUSED) |
6de9cd9a DN |
383 | { |
384 | basic_block bb, *worklist, *tos; | |
3cd8c58a | 385 | unsigned i; |
87c476a2 | 386 | bitmap_iterator bi; |
6de9cd9a DN |
387 | |
388 | tos = worklist | |
0bca51f0 | 389 | = (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1)); |
6de9cd9a | 390 | |
87c476a2 | 391 | EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi) |
38635499 | 392 | *tos++ = BASIC_BLOCK (i); |
6de9cd9a DN |
393 | |
394 | /* Iterate until the worklist is empty. */ | |
395 | while (tos != worklist) | |
396 | { | |
397 | edge e; | |
628f6a4e | 398 | edge_iterator ei; |
6de9cd9a DN |
399 | |
400 | /* Pull a block off the worklist. */ | |
401 | bb = *--tos; | |
402 | ||
403 | /* For each predecessor block. */ | |
628f6a4e | 404 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
405 | { |
406 | basic_block pred = e->src; | |
407 | int pred_index = pred->index; | |
408 | ||
409 | /* None of this is necessary for the entry block. */ | |
410 | if (pred != ENTRY_BLOCK_PTR | |
411 | && ! bitmap_bit_p (livein, pred_index) | |
412 | && ! bitmap_bit_p (def_blocks, pred_index)) | |
413 | { | |
414 | *tos++ = pred; | |
415 | bitmap_set_bit (livein, pred_index); | |
416 | } | |
417 | } | |
418 | } | |
419 | ||
420 | free (worklist); | |
421 | } | |
422 | ||
423 | ||
95dd3097 ZD |
424 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
425 | all statements in basic block BB. */ | |
426 | ||
427 | static void | |
428 | initialize_flags_in_bb (basic_block bb) | |
429 | { | |
726a989a RB |
430 | gimple stmt; |
431 | gimple_stmt_iterator gsi; | |
95dd3097 | 432 | |
726a989a | 433 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 434 | { |
726a989a RB |
435 | gimple phi = gsi_stmt (gsi); |
436 | set_rewrite_uses (phi, false); | |
437 | set_register_defs (phi, false); | |
95dd3097 ZD |
438 | } |
439 | ||
726a989a | 440 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 441 | { |
726a989a RB |
442 | stmt = gsi_stmt (gsi); |
443 | ||
95dd3097 ZD |
444 | /* We are going to use the operand cache API, such as |
445 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
446 | cache for each statement should be up-to-date. */ | |
726a989a RB |
447 | gcc_assert (!gimple_modified_p (stmt)); |
448 | set_rewrite_uses (stmt, false); | |
449 | set_register_defs (stmt, false); | |
95dd3097 ZD |
450 | } |
451 | } | |
452 | ||
453 | /* Mark block BB as interesting for update_ssa. */ | |
454 | ||
455 | static void | |
456 | mark_block_for_update (basic_block bb) | |
457 | { | |
458 | gcc_assert (blocks_to_update != NULL); | |
459 | if (bitmap_bit_p (blocks_to_update, bb->index)) | |
460 | return; | |
461 | bitmap_set_bit (blocks_to_update, bb->index); | |
462 | initialize_flags_in_bb (bb); | |
463 | } | |
464 | ||
7256233c DN |
465 | /* Return the set of blocks where variable VAR is defined and the blocks |
466 | where VAR is live on entry (livein). If no entry is found in | |
467 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 468 | |
7256233c DN |
469 | static inline struct def_blocks_d * |
470 | get_def_blocks_for (tree var) | |
6de9cd9a | 471 | { |
7256233c DN |
472 | struct def_blocks_d db, *db_p; |
473 | void **slot; | |
6de9cd9a | 474 | |
7256233c DN |
475 | db.var = var; |
476 | slot = htab_find_slot (def_blocks, (void *) &db, INSERT); | |
477 | if (*slot == NULL) | |
6de9cd9a | 478 | { |
858904db | 479 | db_p = XNEW (struct def_blocks_d); |
7256233c DN |
480 | db_p->var = var; |
481 | db_p->def_blocks = BITMAP_ALLOC (NULL); | |
482 | db_p->phi_blocks = BITMAP_ALLOC (NULL); | |
483 | db_p->livein_blocks = BITMAP_ALLOC (NULL); | |
484 | *slot = (void *) db_p; | |
a32b97a2 | 485 | } |
7256233c DN |
486 | else |
487 | db_p = (struct def_blocks_d *) *slot; | |
a32b97a2 | 488 | |
7256233c | 489 | return db_p; |
6de9cd9a DN |
490 | } |
491 | ||
7d5f9cc6 | 492 | |
5f240ec4 | 493 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 494 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
495 | |
496 | static void | |
0bca51f0 | 497 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a DN |
498 | { |
499 | struct def_blocks_d *db_p; | |
34eb8991 JL |
500 | enum need_phi_state state; |
501 | ||
5f240ec4 | 502 | state = get_phi_state (var); |
6de9cd9a DN |
503 | db_p = get_def_blocks_for (var); |
504 | ||
505 | /* Set the bit corresponding to the block where VAR is defined. */ | |
506 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
507 | if (phi_p) |
508 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 509 | |
7256233c | 510 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
511 | |
512 | If we are in the UNKNOWN state, then this is the first definition | |
513 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 514 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
515 | transition to NEED_PHI_STATE_NO). |
516 | ||
517 | If we are in any other state, then we either have multiple definitions | |
518 | of this variable occurring in different blocks or we saw a use of the | |
519 | variable which was not dominated by the block containing the | |
520 | definition(s). In this case we may need a PHI node, so enter | |
521 | state NEED_PHI_STATE_MAYBE. */ | |
522 | if (state == NEED_PHI_STATE_UNKNOWN) | |
5f240ec4 | 523 | set_phi_state (var, NEED_PHI_STATE_NO); |
6de9cd9a | 524 | else |
5f240ec4 | 525 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
526 | } |
527 | ||
528 | ||
529 | /* Mark block BB as having VAR live at the entry to BB. */ | |
530 | ||
531 | static void | |
532 | set_livein_block (tree var, basic_block bb) | |
533 | { | |
534 | struct def_blocks_d *db_p; | |
5f240ec4 | 535 | enum need_phi_state state = get_phi_state (var); |
6de9cd9a DN |
536 | |
537 | db_p = get_def_blocks_for (var); | |
538 | ||
539 | /* Set the bit corresponding to the block where VAR is live in. */ | |
540 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
541 | ||
7256233c | 542 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
543 | |
544 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
545 | by the single block containing the definition(s) of this variable. If | |
546 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
547 | NEED_PHI_STATE_MAYBE. */ | |
548 | if (state == NEED_PHI_STATE_NO) | |
549 | { | |
550 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
551 | ||
552 | if (def_block_index == -1 | |
553 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
554 | BASIC_BLOCK (def_block_index))) | |
5f240ec4 | 555 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
556 | } |
557 | else | |
5f240ec4 | 558 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
559 | } |
560 | ||
561 | ||
0bca51f0 | 562 | /* Return true if symbol SYM is marked for renaming. */ |
6de9cd9a | 563 | |
0bca51f0 DN |
564 | static inline bool |
565 | symbol_marked_for_renaming (tree sym) | |
6de9cd9a | 566 | { |
5006671f | 567 | return bitmap_bit_p (SYMS_TO_RENAME (cfun), DECL_UID (sym)); |
0bca51f0 DN |
568 | } |
569 | ||
570 | ||
571 | /* Return true if NAME is in OLD_SSA_NAMES. */ | |
6de9cd9a | 572 | |
0bca51f0 DN |
573 | static inline bool |
574 | is_old_name (tree name) | |
575 | { | |
84d65814 | 576 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
577 | if (!new_ssa_names) |
578 | return false; | |
84d65814 | 579 | return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver); |
0bca51f0 DN |
580 | } |
581 | ||
582 | ||
583 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 584 | |
0bca51f0 DN |
585 | static inline bool |
586 | is_new_name (tree name) | |
587 | { | |
84d65814 | 588 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
589 | if (!new_ssa_names) |
590 | return false; | |
84d65814 | 591 | return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver); |
6de9cd9a DN |
592 | } |
593 | ||
7256233c | 594 | |
0bca51f0 | 595 | /* Hashing and equality functions for REPL_TBL. */ |
d00ad49b | 596 | |
0bca51f0 DN |
597 | static hashval_t |
598 | repl_map_hash (const void *p) | |
d00ad49b | 599 | { |
0bca51f0 DN |
600 | return htab_hash_pointer ((const void *)((const struct repl_map_d *)p)->name); |
601 | } | |
d00ad49b | 602 | |
0bca51f0 DN |
603 | static int |
604 | repl_map_eq (const void *p1, const void *p2) | |
605 | { | |
606 | return ((const struct repl_map_d *)p1)->name | |
607 | == ((const struct repl_map_d *)p2)->name; | |
608 | } | |
609 | ||
610 | static void | |
611 | repl_map_free (void *p) | |
612 | { | |
613 | BITMAP_FREE (((struct repl_map_d *)p)->set); | |
614 | free (p); | |
615 | } | |
616 | ||
617 | ||
82d6e6fc | 618 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
619 | |
620 | static inline bitmap | |
82d6e6fc | 621 | names_replaced_by (tree new_tree) |
0bca51f0 DN |
622 | { |
623 | struct repl_map_d m; | |
624 | void **slot; | |
625 | ||
82d6e6fc | 626 | m.name = new_tree; |
0bca51f0 DN |
627 | slot = htab_find_slot (repl_tbl, (void *) &m, NO_INSERT); |
628 | ||
629 | /* If N was not registered in the replacement table, return NULL. */ | |
630 | if (slot == NULL || *slot == NULL) | |
631 | return NULL; | |
632 | ||
633 | return ((struct repl_map_d *) *slot)->set; | |
634 | } | |
635 | ||
636 | ||
82d6e6fc | 637 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
638 | |
639 | static inline void | |
82d6e6fc | 640 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 DN |
641 | { |
642 | struct repl_map_d m, *mp; | |
643 | void **slot; | |
644 | ||
82d6e6fc | 645 | m.name = new_tree; |
0bca51f0 DN |
646 | slot = htab_find_slot (repl_tbl, (void *) &m, INSERT); |
647 | if (*slot == NULL) | |
648 | { | |
858904db | 649 | mp = XNEW (struct repl_map_d); |
82d6e6fc | 650 | mp->name = new_tree; |
0bca51f0 DN |
651 | mp->set = BITMAP_ALLOC (NULL); |
652 | *slot = (void *) mp; | |
653 | } | |
654 | else | |
655 | mp = (struct repl_map_d *) *slot; | |
656 | ||
657 | bitmap_set_bit (mp->set, SSA_NAME_VERSION (old)); | |
658 | } | |
659 | ||
660 | ||
82d6e6fc | 661 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
662 | represents the set of names O_1 ... O_j replaced by N_i. This is |
663 | used by update_ssa and its helpers to introduce new SSA names in an | |
664 | already formed SSA web. */ | |
665 | ||
666 | static void | |
82d6e6fc | 667 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 DN |
668 | { |
669 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
670 | ||
82d6e6fc KG |
671 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
672 | gcc_assert (new_tree != old && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 673 | |
84d65814 | 674 | /* If this mapping is for virtual names, we will need to update |
38635499 DN |
675 | virtual operands. If this is a mapping for .MEM, then we gather |
676 | the symbols associated with each name. */ | |
82d6e6fc | 677 | if (!is_gimple_reg (new_tree)) |
0bca51f0 DN |
678 | { |
679 | tree sym; | |
680 | ||
38635499 DN |
681 | update_ssa_stats.num_virtual_mappings++; |
682 | update_ssa_stats.num_virtual_symbols++; | |
683 | ||
84d65814 DN |
684 | /* Keep counts of virtual mappings and symbols to use in the |
685 | virtual mapping heuristic. If we have large numbers of | |
686 | virtual mappings for a relatively low number of symbols, it | |
687 | will make more sense to rename the symbols from scratch. | |
688 | Otherwise, the insertion of PHI nodes for each of the old | |
689 | names in these mappings will be very slow. */ | |
82d6e6fc | 690 | sym = SSA_NAME_VAR (new_tree); |
38635499 DN |
691 | bitmap_set_bit (update_ssa_stats.virtual_symbols, DECL_UID (sym)); |
692 | } | |
693 | ||
694 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our | |
695 | caller may have created new names since the set was created. */ | |
696 | if (new_ssa_names->n_bits <= num_ssa_names - 1) | |
697 | { | |
698 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
699 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
700 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
701 | } |
702 | ||
0bca51f0 | 703 | /* Update the REPL_TBL table. */ |
82d6e6fc | 704 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 705 | |
0bca51f0 | 706 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 707 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 708 | if (is_new_name (old)) |
82d6e6fc | 709 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 710 | |
82d6e6fc | 711 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 712 | respectively. */ |
82d6e6fc | 713 | SET_BIT (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
0bca51f0 DN |
714 | SET_BIT (old_ssa_names, SSA_NAME_VERSION (old)); |
715 | ||
84d65814 DN |
716 | /* Update mapping counter to use in the virtual mapping heuristic. */ |
717 | update_ssa_stats.num_total_mappings++; | |
0bca51f0 DN |
718 | |
719 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
d00ad49b | 720 | } |
6de9cd9a | 721 | |
6de9cd9a | 722 | |
7256233c DN |
723 | /* Call back for walk_dominator_tree used to collect definition sites |
724 | for every variable in the function. For every statement S in block | |
725 | BB: | |
6de9cd9a | 726 | |
f47c96aa | 727 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
ccf5c864 | 728 | KILLS. |
6de9cd9a | 729 | |
7256233c | 730 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 731 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 732 | |
7256233c DN |
733 | This information is used to determine which variables are live |
734 | across block boundaries to reduce the number of PHI nodes | |
735 | we create. */ | |
6de9cd9a | 736 | |
7256233c | 737 | static void |
ccf5c864 | 738 | mark_def_sites (basic_block bb, gimple stmt, bitmap kills) |
7256233c | 739 | { |
726a989a | 740 | tree def; |
7256233c | 741 | use_operand_p use_p; |
7256233c DN |
742 | ssa_op_iter iter; |
743 | ||
726a989a RB |
744 | /* Since this is the first time that we rewrite the program into SSA |
745 | form, force an operand scan on every statement. */ | |
726a989a | 746 | update_stmt (stmt); |
7256233c | 747 | |
95dd3097 | 748 | gcc_assert (blocks_to_update == NULL); |
726a989a RB |
749 | set_register_defs (stmt, false); |
750 | set_rewrite_uses (stmt, false); | |
7256233c | 751 | |
b5b8b0ac AO |
752 | if (is_gimple_debug (stmt)) |
753 | return; | |
754 | ||
7256233c DN |
755 | /* If a variable is used before being set, then the variable is live |
756 | across a block boundary, so mark it live-on-entry to BB. */ | |
38635499 | 757 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
7256233c | 758 | { |
0bca51f0 DN |
759 | tree sym = USE_FROM_PTR (use_p); |
760 | gcc_assert (DECL_P (sym)); | |
a3648cfc | 761 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 762 | set_livein_block (sym, bb); |
726a989a | 763 | set_rewrite_uses (stmt, true); |
7256233c | 764 | } |
b8698a0f | 765 | |
38635499 DN |
766 | /* Now process the defs. Mark BB as the definition block and add |
767 | each def to the set of killed symbols. */ | |
768 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) | |
7256233c | 769 | { |
0bca51f0 DN |
770 | gcc_assert (DECL_P (def)); |
771 | set_def_block (def, bb, false); | |
a3648cfc | 772 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 773 | set_register_defs (stmt, true); |
7256233c | 774 | } |
0bca51f0 DN |
775 | |
776 | /* If we found the statement interesting then also mark the block BB | |
777 | as interesting. */ | |
726a989a | 778 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
ccf5c864 | 779 | SET_BIT (interesting_blocks, bb->index); |
7256233c DN |
780 | } |
781 | ||
f074ff6c ZD |
782 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
783 | in the dfs numbering of the dominance tree. */ | |
784 | ||
785 | struct dom_dfsnum | |
786 | { | |
787 | /* Basic block whose index this entry corresponds to. */ | |
788 | unsigned bb_index; | |
789 | ||
790 | /* The dfs number of this node. */ | |
791 | unsigned dfs_num; | |
792 | }; | |
793 | ||
794 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
795 | for qsort. */ | |
796 | ||
797 | static int | |
798 | cmp_dfsnum (const void *a, const void *b) | |
799 | { | |
3d9a9f94 KG |
800 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
801 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
802 | |
803 | return (int) da->dfs_num - (int) db->dfs_num; | |
804 | } | |
805 | ||
806 | /* Among the intervals starting at the N points specified in DEFS, find | |
807 | the one that contains S, and return its bb_index. */ | |
808 | ||
809 | static unsigned | |
810 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
811 | { | |
812 | unsigned f = 0, t = n, m; | |
813 | ||
814 | while (t > f + 1) | |
815 | { | |
816 | m = (f + t) / 2; | |
817 | if (defs[m].dfs_num <= s) | |
818 | f = m; | |
819 | else | |
820 | t = m; | |
821 | } | |
822 | ||
823 | return defs[f].bb_index; | |
824 | } | |
825 | ||
826 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
827 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
828 | ||
829 | static void | |
830 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
831 | { | |
832 | VEC(int, heap) *worklist; | |
833 | bitmap_iterator bi; | |
834 | unsigned i, b, p, u, top; | |
835 | bitmap live_phis; | |
836 | basic_block def_bb, use_bb; | |
837 | edge e; | |
838 | edge_iterator ei; | |
839 | bitmap to_remove; | |
840 | struct dom_dfsnum *defs; | |
841 | unsigned n_defs, adef; | |
842 | ||
843 | if (bitmap_empty_p (uses)) | |
844 | { | |
845 | bitmap_clear (phis); | |
846 | return; | |
847 | } | |
848 | ||
849 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
850 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
851 | to_remove = BITMAP_ALLOC (NULL); | |
852 | bitmap_and_compl (to_remove, kills, uses); | |
853 | bitmap_and_compl_into (phis, to_remove); | |
854 | if (bitmap_empty_p (phis)) | |
855 | { | |
856 | BITMAP_FREE (to_remove); | |
857 | return; | |
858 | } | |
859 | ||
860 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
861 | liveness information, as that may be linear in the size of CFG, and if | |
862 | there are lot of different variables to rewrite, this may lead to quadratic | |
863 | behavior. | |
864 | ||
865 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
866 | then for each of them find the nearest def that dominates them. If this | |
867 | def is a phi node, we mark it live, and if it was not live before, we | |
868 | add the predecessors of its basic block to the worklist. | |
b8698a0f | 869 | |
f074ff6c ZD |
870 | To quickly locate the nearest def that dominates use, we use dfs numbering |
871 | of the dominance tree (that is already available in order to speed up | |
872 | queries). For each def, we have the interval given by the dfs number on | |
873 | entry to and on exit from the corresponding subtree in the dominance tree. | |
874 | The nearest dominator for a given use is the smallest of these intervals | |
875 | that contains entry and exit dfs numbers for the basic block with the use. | |
876 | If we store the bounds for all the uses to an array and sort it, we can | |
877 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
878 | bitmap_ior (to_remove, kills, phis); | |
879 | n_defs = bitmap_count_bits (to_remove); | |
880 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
881 | defs[0].bb_index = 1; | |
882 | defs[0].dfs_num = 0; | |
883 | adef = 1; | |
884 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
885 | { | |
886 | def_bb = BASIC_BLOCK (i); | |
887 | defs[adef].bb_index = i; | |
888 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
889 | defs[adef + 1].bb_index = i; | |
890 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
891 | adef += 2; | |
892 | } | |
893 | BITMAP_FREE (to_remove); | |
894 | gcc_assert (adef == 2 * n_defs + 1); | |
895 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
896 | gcc_assert (defs[0].bb_index == 1); | |
897 | ||
898 | /* Now each DEFS entry contains the number of the basic block to that the | |
899 | dfs number corresponds. Change them to the number of basic block that | |
900 | corresponds to the interval following the dfs number. Also, for the | |
901 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
902 | to the start of the following interval, not to the end of the current | |
903 | one). We use WORKLIST as a stack. */ | |
904 | worklist = VEC_alloc (int, heap, n_defs + 1); | |
905 | VEC_quick_push (int, worklist, 1); | |
906 | top = 1; | |
907 | n_defs = 1; | |
908 | for (i = 1; i < adef; i++) | |
909 | { | |
910 | b = defs[i].bb_index; | |
911 | if (b == top) | |
912 | { | |
913 | /* This is a closing element. Interval corresponding to the top | |
914 | of the stack after removing it follows. */ | |
915 | VEC_pop (int, worklist); | |
916 | top = VEC_index (int, worklist, VEC_length (int, worklist) - 1); | |
917 | defs[n_defs].bb_index = top; | |
918 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
919 | } | |
920 | else | |
921 | { | |
922 | /* Opening element. Nothing to do, just push it to the stack and move | |
923 | it to the correct position. */ | |
924 | defs[n_defs].bb_index = defs[i].bb_index; | |
925 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
926 | VEC_quick_push (int, worklist, b); | |
927 | top = b; | |
928 | } | |
929 | ||
930 | /* If this interval starts at the same point as the previous one, cancel | |
931 | the previous one. */ | |
932 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
933 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
934 | else | |
935 | n_defs++; | |
936 | } | |
937 | VEC_pop (int, worklist); | |
938 | gcc_assert (VEC_empty (int, worklist)); | |
939 | ||
940 | /* Now process the uses. */ | |
941 | live_phis = BITMAP_ALLOC (NULL); | |
942 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
943 | { | |
944 | VEC_safe_push (int, heap, worklist, i); | |
945 | } | |
946 | ||
947 | while (!VEC_empty (int, worklist)) | |
948 | { | |
949 | b = VEC_pop (int, worklist); | |
950 | if (b == ENTRY_BLOCK) | |
951 | continue; | |
952 | ||
953 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
954 | find the def that dominates the immediate dominator of USE_BB | |
955 | (the kill in USE_BB does not dominate the use). */ | |
956 | if (bitmap_bit_p (phis, b)) | |
957 | p = b; | |
958 | else | |
959 | { | |
960 | use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b)); | |
961 | p = find_dfsnum_interval (defs, n_defs, | |
962 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
963 | if (!bitmap_bit_p (phis, p)) | |
964 | continue; | |
965 | } | |
966 | ||
967 | /* If the phi node is already live, there is nothing to do. */ | |
968 | if (bitmap_bit_p (live_phis, p)) | |
969 | continue; | |
970 | ||
971 | /* Mark the phi as live, and add the new uses to the worklist. */ | |
972 | bitmap_set_bit (live_phis, p); | |
973 | def_bb = BASIC_BLOCK (p); | |
974 | FOR_EACH_EDGE (e, ei, def_bb->preds) | |
975 | { | |
976 | u = e->src->index; | |
977 | if (bitmap_bit_p (uses, u)) | |
978 | continue; | |
979 | ||
1e5787ef ZD |
980 | /* In case there is a kill directly in the use block, do not record |
981 | the use (this is also necessary for correctness, as we assume that | |
982 | uses dominated by a def directly in their block have been filtered | |
983 | out before). */ | |
984 | if (bitmap_bit_p (kills, u)) | |
985 | continue; | |
986 | ||
f074ff6c ZD |
987 | bitmap_set_bit (uses, u); |
988 | VEC_safe_push (int, heap, worklist, u); | |
989 | } | |
990 | } | |
991 | ||
992 | VEC_free (int, heap, worklist); | |
993 | bitmap_copy (phis, live_phis); | |
994 | BITMAP_FREE (live_phis); | |
995 | free (defs); | |
996 | } | |
7256233c | 997 | |
7256233c DN |
998 | /* Return the set of blocks where variable VAR is defined and the blocks |
999 | where VAR is live on entry (livein). Return NULL, if no entry is | |
1000 | found in DEF_BLOCKS. */ | |
1001 | ||
1002 | static inline struct def_blocks_d * | |
1003 | find_def_blocks_for (tree var) | |
1004 | { | |
1005 | struct def_blocks_d dm; | |
1006 | dm.var = var; | |
1007 | return (struct def_blocks_d *) htab_find (def_blocks, &dm); | |
1008 | } | |
1009 | ||
1010 | ||
0bca51f0 DN |
1011 | /* Retrieve or create a default definition for symbol SYM. */ |
1012 | ||
1013 | static inline tree | |
1014 | get_default_def_for (tree sym) | |
1015 | { | |
5cd4ec7f | 1016 | tree ddef = gimple_default_def (cfun, sym); |
0bca51f0 DN |
1017 | |
1018 | if (ddef == NULL_TREE) | |
1019 | { | |
726a989a | 1020 | ddef = make_ssa_name (sym, gimple_build_nop ()); |
0bca51f0 DN |
1021 | set_default_def (sym, ddef); |
1022 | } | |
1023 | ||
1024 | return ddef; | |
1025 | } | |
1026 | ||
1027 | ||
2ce79879 ZD |
1028 | /* Marks phi node PHI in basic block BB for rewrite. */ |
1029 | ||
1030 | static void | |
726a989a | 1031 | mark_phi_for_rewrite (basic_block bb, gimple phi) |
2ce79879 | 1032 | { |
726a989a | 1033 | gimple_vec phis; |
2ce79879 ZD |
1034 | unsigned i, idx = bb->index; |
1035 | ||
726a989a | 1036 | if (rewrite_uses_p (phi)) |
2ce79879 | 1037 | return; |
38635499 | 1038 | |
726a989a | 1039 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
1040 | |
1041 | if (!blocks_with_phis_to_rewrite) | |
1042 | return; | |
1043 | ||
1044 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
726a989a RB |
1045 | VEC_reserve (gimple_vec, heap, phis_to_rewrite, last_basic_block + 1); |
1046 | for (i = VEC_length (gimple_vec, phis_to_rewrite); i <= idx; i++) | |
1047 | VEC_quick_push (gimple_vec, phis_to_rewrite, NULL); | |
2ce79879 | 1048 | |
726a989a | 1049 | phis = VEC_index (gimple_vec, phis_to_rewrite, idx); |
2ce79879 | 1050 | if (!phis) |
726a989a | 1051 | phis = VEC_alloc (gimple, heap, 10); |
2ce79879 | 1052 | |
726a989a RB |
1053 | VEC_safe_push (gimple, heap, phis, phi); |
1054 | VEC_replace (gimple_vec, phis_to_rewrite, idx, phis); | |
2ce79879 ZD |
1055 | } |
1056 | ||
7256233c | 1057 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 1058 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
1059 | function assumes that the caller is incrementally updating the |
1060 | existing SSA form, in which case VAR may be an SSA name instead of | |
1061 | a symbol. | |
0bca51f0 DN |
1062 | |
1063 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
1064 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
1065 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
1066 | |
1067 | static void | |
0bca51f0 | 1068 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
1069 | { |
1070 | unsigned bb_index; | |
1071 | edge e; | |
726a989a | 1072 | gimple phi; |
7256233c DN |
1073 | basic_block bb; |
1074 | bitmap_iterator bi; | |
1075 | struct def_blocks_d *def_map; | |
1076 | ||
1077 | def_map = find_def_blocks_for (var); | |
0bca51f0 | 1078 | gcc_assert (def_map); |
7256233c DN |
1079 | |
1080 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
1081 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
1082 | ||
f074ff6c ZD |
1083 | /* Remove obviously useless phi nodes. */ |
1084 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
1085 | def_map->livein_blocks); | |
7256233c DN |
1086 | |
1087 | /* And insert the PHI nodes. */ | |
f074ff6c | 1088 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c DN |
1089 | { |
1090 | bb = BASIC_BLOCK (bb_index); | |
95dd3097 ZD |
1091 | if (update_p) |
1092 | mark_block_for_update (bb); | |
7256233c | 1093 | |
726a989a | 1094 | phi = NULL; |
38635499 DN |
1095 | |
1096 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 1097 | { |
84d65814 DN |
1098 | /* If we are rewriting SSA names, create the LHS of the PHI |
1099 | node by duplicating VAR. This is useful in the case of | |
1100 | pointers, to also duplicate pointer attributes (alias | |
1101 | information, in particular). */ | |
7256233c | 1102 | edge_iterator ei; |
84d65814 | 1103 | tree new_lhs; |
0bca51f0 | 1104 | |
38635499 | 1105 | gcc_assert (update_p); |
84d65814 | 1106 | phi = create_phi_node (var, bb); |
38635499 | 1107 | |
84d65814 | 1108 | new_lhs = duplicate_ssa_name (var, phi); |
726a989a | 1109 | gimple_phi_set_result (phi, new_lhs); |
84d65814 | 1110 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1111 | |
1112 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1113 | every argument so that rewrite_update_phi_arguments knows | |
1114 | which name is this PHI node replacing. If VAR is a | |
1115 | symbol marked for renaming, this is not necessary, the | |
1116 | renamer will use the symbol on the LHS to get its | |
1117 | reaching definition. */ | |
7256233c | 1118 | FOR_EACH_EDGE (e, ei, bb->preds) |
f5045c96 | 1119 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
7256233c | 1120 | } |
84d65814 DN |
1121 | else |
1122 | { | |
b5b8b0ac | 1123 | tree tracked_var; |
3a56edc7 | 1124 | |
e24c4814 SB |
1125 | gcc_assert (DECL_P (var)); |
1126 | phi = create_phi_node (var, bb); | |
3a56edc7 AO |
1127 | |
1128 | tracked_var = target_for_debug_bind (var); | |
1129 | if (tracked_var) | |
b5b8b0ac AO |
1130 | { |
1131 | gimple note = gimple_build_debug_bind (tracked_var, | |
1132 | PHI_RESULT (phi), | |
1133 | phi); | |
1134 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1135 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1136 | } | |
84d65814 | 1137 | } |
0bca51f0 DN |
1138 | |
1139 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1140 | set_register_defs (phi, true); |
2ce79879 | 1141 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1142 | } |
1143 | } | |
1144 | ||
1145 | ||
7256233c DN |
1146 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1147 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1148 | the flowgraph. */ |
7256233c DN |
1149 | |
1150 | static void | |
84d65814 | 1151 | insert_phi_nodes (bitmap *dfs) |
7256233c | 1152 | { |
a3648cfc DB |
1153 | referenced_var_iterator rvi; |
1154 | tree var; | |
7256233c DN |
1155 | |
1156 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
b8698a0f | 1157 | |
a3648cfc | 1158 | FOR_EACH_REFERENCED_VAR (var, rvi) |
5f240ec4 | 1159 | { |
84d65814 DN |
1160 | struct def_blocks_d *def_map; |
1161 | bitmap idf; | |
0bca51f0 | 1162 | |
84d65814 DN |
1163 | def_map = find_def_blocks_for (var); |
1164 | if (def_map == NULL) | |
1165 | continue; | |
1166 | ||
1167 | if (get_phi_state (var) != NEED_PHI_STATE_NO) | |
1168 | { | |
38635499 | 1169 | idf = compute_idf (def_map->def_blocks, dfs); |
84d65814 DN |
1170 | insert_phi_nodes_for (var, idf, false); |
1171 | BITMAP_FREE (idf); | |
1172 | } | |
7256233c | 1173 | } |
5f240ec4 | 1174 | |
6de9cd9a DN |
1175 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1176 | } | |
1177 | ||
1178 | ||
38635499 DN |
1179 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1180 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1181 | |
cfaab3a9 | 1182 | static void |
38635499 | 1183 | register_new_def (tree def, tree sym) |
7256233c | 1184 | { |
7256233c | 1185 | tree currdef; |
b8698a0f | 1186 | |
7256233c DN |
1187 | /* If this variable is set in a single basic block and all uses are |
1188 | dominated by the set(s) in that single basic block, then there is | |
1189 | no reason to record anything for this variable in the block local | |
1190 | definition stacks. Doing so just wastes time and memory. | |
1191 | ||
1192 | This is the same test to prune the set of variables which may | |
1193 | need PHI nodes. So we just use that information since it's already | |
1194 | computed and available for us to use. */ | |
38635499 | 1195 | if (get_phi_state (sym) == NEED_PHI_STATE_NO) |
7256233c | 1196 | { |
38635499 | 1197 | set_current_def (sym, def); |
7256233c DN |
1198 | return; |
1199 | } | |
1200 | ||
38635499 | 1201 | currdef = get_current_def (sym); |
7256233c | 1202 | |
38635499 DN |
1203 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1204 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1205 | in the stack so that we know which symbol is being defined by | |
1206 | this SSA name when we unwind the stack. */ | |
1207 | if (currdef && !is_gimple_reg (sym)) | |
1208 | VEC_safe_push (tree, heap, block_defs_stack, sym); | |
7256233c | 1209 | |
38635499 DN |
1210 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1211 | stack is later used by the dominator tree callbacks to restore | |
1212 | the reaching definitions for all the variables defined in the | |
1213 | block after a recursive visit to all its immediately dominated | |
1214 | blocks. If there is no current reaching definition, then just | |
1215 | record the underlying _DECL node. */ | |
1216 | VEC_safe_push (tree, heap, block_defs_stack, currdef ? currdef : sym); | |
1217 | ||
1218 | /* Set the current reaching definition for SYM to be DEF. */ | |
1219 | set_current_def (sym, def); | |
7256233c DN |
1220 | } |
1221 | ||
1222 | ||
6de9cd9a DN |
1223 | /* Perform a depth-first traversal of the dominator tree looking for |
1224 | variables to rename. BB is the block where to start searching. | |
1225 | Renaming is a five step process: | |
1226 | ||
1227 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1228 | registered as the current definition for the corresponding variable. | |
1229 | ||
1230 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1231 | rewritten with their corresponding reaching definition. DEF and | |
1232 | VDEF targets are registered as new definitions. | |
b8698a0f | 1233 | |
6de9cd9a DN |
1234 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1235 | argument corresponding to BB is replaced with its current reaching | |
1236 | definition. | |
1237 | ||
1238 | 4- Recursively rewrite every dominator child block of BB. | |
1239 | ||
1240 | 5- Restore (in reverse order) the current reaching definition for every | |
1241 | new definition introduced in this block. This is done so that when | |
1242 | we return from the recursive call, all the current reaching | |
1243 | definitions are restored to the names that were valid in the | |
1244 | dominator parent of BB. */ | |
1245 | ||
7256233c | 1246 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1247 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1248 | |
7256233c DN |
1249 | static tree |
1250 | get_reaching_def (tree var) | |
1251 | { | |
38635499 | 1252 | tree currdef; |
b8698a0f | 1253 | |
7256233c | 1254 | /* Lookup the current reaching definition for VAR. */ |
38635499 | 1255 | currdef = get_current_def (var); |
5f240ec4 | 1256 | |
7256233c DN |
1257 | /* If there is no reaching definition for VAR, create and register a |
1258 | default definition for it (if needed). */ | |
38635499 | 1259 | if (currdef == NULL_TREE) |
7256233c | 1260 | { |
38635499 DN |
1261 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
1262 | currdef = get_default_def_for (sym); | |
1263 | set_current_def (var, currdef); | |
7256233c DN |
1264 | } |
1265 | ||
1266 | /* Return the current reaching definition for VAR, or the default | |
1267 | definition, if we had to create one. */ | |
38635499 | 1268 | return currdef; |
7256233c DN |
1269 | } |
1270 | ||
1271 | ||
1272 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in | |
1273 | the block with its immediate reaching definitions. Update the current | |
1274 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1275 | |
1276 | static void | |
b5b8b0ac | 1277 | rewrite_stmt (gimple_stmt_iterator si) |
5f240ec4 | 1278 | { |
7256233c DN |
1279 | use_operand_p use_p; |
1280 | def_operand_p def_p; | |
1281 | ssa_op_iter iter; | |
b5b8b0ac | 1282 | gimple stmt = gsi_stmt (si); |
7256233c | 1283 | |
7256233c DN |
1284 | /* If mark_def_sites decided that we don't need to rewrite this |
1285 | statement, ignore it. */ | |
95dd3097 | 1286 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1287 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1288 | return; |
5f240ec4 ZD |
1289 | |
1290 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1291 | { |
1292 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1293 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1294 | fprintf (dump_file, "\n"); |
1295 | } | |
5f240ec4 | 1296 | |
38635499 | 1297 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1298 | if (rewrite_uses_p (stmt)) |
38635499 | 1299 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
0bca51f0 DN |
1300 | { |
1301 | tree var = USE_FROM_PTR (use_p); | |
1302 | gcc_assert (DECL_P (var)); | |
1303 | SET_USE (use_p, get_reaching_def (var)); | |
1304 | } | |
5f240ec4 | 1305 | |
38635499 | 1306 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1307 | if (register_defs_p (stmt)) |
38635499 | 1308 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) |
0bca51f0 DN |
1309 | { |
1310 | tree var = DEF_FROM_PTR (def_p); | |
b5b8b0ac AO |
1311 | tree name = make_ssa_name (var, stmt); |
1312 | tree tracked_var; | |
0bca51f0 | 1313 | gcc_assert (DECL_P (var)); |
b5b8b0ac | 1314 | SET_DEF (def_p, name); |
38635499 | 1315 | register_new_def (DEF_FROM_PTR (def_p), var); |
b5b8b0ac AO |
1316 | |
1317 | tracked_var = target_for_debug_bind (var); | |
1318 | if (tracked_var) | |
1319 | { | |
1320 | gimple note = gimple_build_debug_bind (tracked_var, name, stmt); | |
1321 | gsi_insert_after (&si, note, GSI_SAME_STMT); | |
1322 | } | |
0bca51f0 | 1323 | } |
5f240ec4 | 1324 | } |
6de9cd9a | 1325 | |
7256233c | 1326 | |
6de9cd9a DN |
1327 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1328 | PHI nodes. For every PHI node found, add a new argument containing the | |
1329 | current reaching definition for the variable and the edge through which | |
471854f8 | 1330 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1331 | |
1332 | static void | |
ccf5c864 | 1333 | rewrite_add_phi_arguments (basic_block bb) |
6de9cd9a DN |
1334 | { |
1335 | edge e; | |
628f6a4e | 1336 | edge_iterator ei; |
6de9cd9a | 1337 | |
628f6a4e | 1338 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1339 | { |
726a989a RB |
1340 | gimple phi; |
1341 | gimple_stmt_iterator gsi; | |
6de9cd9a | 1342 | |
726a989a RB |
1343 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1344 | gsi_next (&gsi)) | |
6de9cd9a DN |
1345 | { |
1346 | tree currdef; | |
f5045c96 AM |
1347 | gimple stmt; |
1348 | ||
726a989a RB |
1349 | phi = gsi_stmt (gsi); |
1350 | currdef = get_reaching_def (SSA_NAME_VAR (gimple_phi_result (phi))); | |
f5045c96 AM |
1351 | stmt = SSA_NAME_DEF_STMT (currdef); |
1352 | add_phi_arg (phi, currdef, e, gimple_location (stmt)); | |
6de9cd9a DN |
1353 | } |
1354 | } | |
1355 | } | |
1356 | ||
ccf5c864 PB |
1357 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1358 | of reaching definitions for new SSA names produced in this block | |
1359 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1360 | block. */ | |
1361 | ||
1362 | static void | |
1363 | rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1364 | basic_block bb) | |
1365 | { | |
1366 | gimple phi; | |
1367 | gimple_stmt_iterator gsi; | |
1368 | ||
1369 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1370 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1371 | ||
1372 | /* Mark the unwind point for this block. */ | |
1373 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
1374 | ||
1375 | /* Step 1. Register new definitions for every PHI node in the block. | |
1376 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1377 | node introduces a new version for the associated variable. */ | |
1378 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1379 | { | |
1380 | tree result; | |
1381 | ||
1382 | phi = gsi_stmt (gsi); | |
1383 | result = gimple_phi_result (phi); | |
1384 | gcc_assert (is_gimple_reg (result)); | |
1385 | register_new_def (result, SSA_NAME_VAR (result)); | |
1386 | } | |
1387 | ||
1388 | /* Step 2. Rewrite every variable used in each statement in the block | |
1389 | with its immediate reaching definitions. Update the current definition | |
1390 | of a variable when a new real or virtual definition is found. */ | |
1391 | if (TEST_BIT (interesting_blocks, bb->index)) | |
1392 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
b5b8b0ac | 1393 | rewrite_stmt (gsi); |
ccf5c864 PB |
1394 | |
1395 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1396 | For every PHI node found, add a new argument containing the current | |
1397 | reaching definition for the variable and the edge through which that | |
1398 | definition is reaching the PHI node. */ | |
1399 | rewrite_add_phi_arguments (bb); | |
1400 | } | |
1401 | ||
1402 | ||
7256233c | 1403 | |
38635499 DN |
1404 | /* Called after visiting all the statements in basic block BB and all |
1405 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a DN |
1406 | |
1407 | static void | |
ccf5c864 PB |
1408 | rewrite_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1409 | basic_block bb ATTRIBUTE_UNUSED) | |
6de9cd9a | 1410 | { |
9fae925b | 1411 | /* Restore CURRDEFS to its original state. */ |
d4e6fecb | 1412 | while (VEC_length (tree, block_defs_stack) > 0) |
6de9cd9a | 1413 | { |
d4e6fecb | 1414 | tree tmp = VEC_pop (tree, block_defs_stack); |
6de9cd9a DN |
1415 | tree saved_def, var; |
1416 | ||
9fae925b JL |
1417 | if (tmp == NULL_TREE) |
1418 | break; | |
1419 | ||
6de9cd9a DN |
1420 | if (TREE_CODE (tmp) == SSA_NAME) |
1421 | { | |
38635499 DN |
1422 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1423 | current definition of its underlying variable. Note that | |
1424 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1425 | being defined is stored in the next slot in the stack. | |
1426 | This mechanism is needed because an SSA name for a | |
1427 | non-register symbol may be the definition for more than | |
1428 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1429 | saved_def = tmp; |
1430 | var = SSA_NAME_VAR (saved_def); | |
38635499 DN |
1431 | if (!is_gimple_reg (var)) |
1432 | var = VEC_pop (tree, block_defs_stack); | |
6de9cd9a DN |
1433 | } |
1434 | else | |
1435 | { | |
38635499 DN |
1436 | /* If we recorded anything else, it must have been a _DECL |
1437 | node and its current reaching definition must have been | |
1438 | NULL. */ | |
6de9cd9a DN |
1439 | saved_def = NULL; |
1440 | var = tmp; | |
1441 | } | |
b8698a0f | 1442 | |
5f240ec4 | 1443 | set_current_def (var, saved_def); |
6de9cd9a DN |
1444 | } |
1445 | } | |
1446 | ||
1447 | ||
38635499 DN |
1448 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1449 | ||
1450 | void | |
1451 | dump_decl_set (FILE *file, bitmap set) | |
1452 | { | |
1453 | if (set) | |
1454 | { | |
3b302421 RG |
1455 | bitmap_iterator bi; |
1456 | unsigned i; | |
38635499 DN |
1457 | |
1458 | fprintf (file, "{ "); | |
1459 | ||
3b302421 | 1460 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
38635499 | 1461 | { |
3b302421 | 1462 | print_generic_expr (file, referenced_var (i), 0); |
38635499 DN |
1463 | fprintf (file, " "); |
1464 | } | |
1465 | ||
5006671f | 1466 | fprintf (file, "}"); |
38635499 DN |
1467 | } |
1468 | else | |
5006671f | 1469 | fprintf (file, "NIL"); |
38635499 DN |
1470 | } |
1471 | ||
1472 | ||
1473 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ | |
1474 | ||
1475 | void | |
1476 | debug_decl_set (bitmap set) | |
1477 | { | |
1478 | dump_decl_set (stderr, set); | |
5006671f | 1479 | fprintf (stderr, "\n"); |
38635499 DN |
1480 | } |
1481 | ||
1482 | ||
1483 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1484 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1485 | dumped. New levels are created when the dominator tree traversal | |
1486 | used for renaming enters a new sub-tree. */ | |
1487 | ||
1488 | void | |
1489 | dump_defs_stack (FILE *file, int n) | |
1490 | { | |
1491 | int i, j; | |
1492 | ||
1493 | fprintf (file, "\n\nRenaming stack"); | |
1494 | if (n > 0) | |
1495 | fprintf (file, " (up to %d levels)", n); | |
1496 | fprintf (file, "\n\n"); | |
1497 | ||
1498 | i = 1; | |
1499 | fprintf (file, "Level %d (current level)\n", i); | |
1500 | for (j = (int) VEC_length (tree, block_defs_stack) - 1; j >= 0; j--) | |
1501 | { | |
1502 | tree name, var; | |
b8698a0f | 1503 | |
38635499 DN |
1504 | name = VEC_index (tree, block_defs_stack, j); |
1505 | if (name == NULL_TREE) | |
1506 | { | |
1507 | i++; | |
1508 | if (n > 0 && i > n) | |
1509 | break; | |
1510 | fprintf (file, "\nLevel %d\n", i); | |
1511 | continue; | |
1512 | } | |
1513 | ||
1514 | if (DECL_P (name)) | |
1515 | { | |
1516 | var = name; | |
1517 | name = NULL_TREE; | |
1518 | } | |
1519 | else | |
1520 | { | |
1521 | var = SSA_NAME_VAR (name); | |
1522 | if (!is_gimple_reg (var)) | |
1523 | { | |
1524 | j--; | |
1525 | var = VEC_index (tree, block_defs_stack, j); | |
1526 | } | |
1527 | } | |
1528 | ||
1529 | fprintf (file, " Previous CURRDEF ("); | |
1530 | print_generic_expr (file, var, 0); | |
1531 | fprintf (file, ") = "); | |
1532 | if (name) | |
1533 | print_generic_expr (file, name, 0); | |
1534 | else | |
1535 | fprintf (file, "<NIL>"); | |
1536 | fprintf (file, "\n"); | |
1537 | } | |
1538 | } | |
1539 | ||
1540 | ||
1541 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1542 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1543 | dumped. New levels are created when the dominator tree traversal | |
1544 | used for renaming enters a new sub-tree. */ | |
1545 | ||
1546 | void | |
1547 | debug_defs_stack (int n) | |
1548 | { | |
1549 | dump_defs_stack (stderr, n); | |
1550 | } | |
1551 | ||
1552 | ||
1553 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1554 | ||
1555 | void | |
1556 | dump_currdefs (FILE *file) | |
1557 | { | |
1558 | referenced_var_iterator i; | |
1559 | tree var; | |
1560 | ||
1561 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); | |
1562 | FOR_EACH_REFERENCED_VAR (var, i) | |
5006671f RG |
1563 | if (SYMS_TO_RENAME (cfun) == NULL |
1564 | || bitmap_bit_p (SYMS_TO_RENAME (cfun), DECL_UID (var))) | |
38635499 DN |
1565 | { |
1566 | fprintf (file, "CURRDEF ("); | |
1567 | print_generic_expr (file, var, 0); | |
1568 | fprintf (file, ") = "); | |
1569 | if (get_current_def (var)) | |
1570 | print_generic_expr (file, get_current_def (var), 0); | |
1571 | else | |
1572 | fprintf (file, "<NIL>"); | |
1573 | fprintf (file, "\n"); | |
1574 | } | |
1575 | } | |
1576 | ||
1577 | ||
1578 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1579 | ||
1580 | void | |
1581 | debug_currdefs (void) | |
1582 | { | |
1583 | dump_currdefs (stderr); | |
1584 | } | |
1585 | ||
1586 | ||
6de9cd9a DN |
1587 | /* Dump SSA information to FILE. */ |
1588 | ||
1589 | void | |
1590 | dump_tree_ssa (FILE *file) | |
1591 | { | |
6de9cd9a | 1592 | const char *funcname |
673fda6b | 1593 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1594 | |
38635499 | 1595 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1596 | |
38635499 DN |
1597 | dump_def_blocks (file); |
1598 | dump_defs_stack (file, -1); | |
1599 | dump_currdefs (file); | |
1600 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1601 | } |
1602 | ||
1603 | ||
1604 | /* Dump SSA information to stderr. */ | |
1605 | ||
1606 | void | |
1607 | debug_tree_ssa (void) | |
1608 | { | |
1609 | dump_tree_ssa (stderr); | |
1610 | } | |
1611 | ||
1612 | ||
7256233c DN |
1613 | /* Dump statistics for the hash table HTAB. */ |
1614 | ||
1615 | static void | |
1616 | htab_statistics (FILE *file, htab_t htab) | |
1617 | { | |
1618 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1619 | (long) htab_size (htab), | |
1620 | (long) htab_elements (htab), | |
1621 | htab_collisions (htab)); | |
1622 | } | |
1623 | ||
1624 | ||
6de9cd9a DN |
1625 | /* Dump SSA statistics on FILE. */ |
1626 | ||
1627 | void | |
1628 | dump_tree_ssa_stats (FILE *file) | |
1629 | { | |
38635499 DN |
1630 | if (def_blocks || repl_tbl) |
1631 | fprintf (file, "\nHash table statistics:\n"); | |
6de9cd9a | 1632 | |
38635499 DN |
1633 | if (def_blocks) |
1634 | { | |
1635 | fprintf (file, " def_blocks: "); | |
1636 | htab_statistics (file, def_blocks); | |
1637 | } | |
6de9cd9a | 1638 | |
38635499 DN |
1639 | if (repl_tbl) |
1640 | { | |
1641 | fprintf (file, " repl_tbl: "); | |
1642 | htab_statistics (file, repl_tbl); | |
1643 | } | |
1644 | ||
1645 | if (def_blocks || repl_tbl) | |
1646 | fprintf (file, "\n"); | |
6de9cd9a DN |
1647 | } |
1648 | ||
1649 | ||
1650 | /* Dump SSA statistics on stderr. */ | |
1651 | ||
1652 | void | |
1653 | debug_tree_ssa_stats (void) | |
1654 | { | |
1655 | dump_tree_ssa_stats (stderr); | |
1656 | } | |
1657 | ||
1658 | ||
7256233c | 1659 | /* Hashing and equality functions for DEF_BLOCKS. */ |
6de9cd9a | 1660 | |
7256233c DN |
1661 | static hashval_t |
1662 | def_blocks_hash (const void *p) | |
6de9cd9a | 1663 | { |
7256233c DN |
1664 | return htab_hash_pointer |
1665 | ((const void *)((const struct def_blocks_d *)p)->var); | |
1666 | } | |
1667 | ||
1668 | static int | |
1669 | def_blocks_eq (const void *p1, const void *p2) | |
1670 | { | |
1671 | return ((const struct def_blocks_d *)p1)->var | |
1672 | == ((const struct def_blocks_d *)p2)->var; | |
6de9cd9a DN |
1673 | } |
1674 | ||
1675 | ||
7256233c | 1676 | /* Free memory allocated by one entry in DEF_BLOCKS. */ |
6de9cd9a DN |
1677 | |
1678 | static void | |
7256233c | 1679 | def_blocks_free (void *p) |
6de9cd9a | 1680 | { |
858904db | 1681 | struct def_blocks_d *entry = (struct def_blocks_d *) p; |
7256233c DN |
1682 | BITMAP_FREE (entry->def_blocks); |
1683 | BITMAP_FREE (entry->phi_blocks); | |
1684 | BITMAP_FREE (entry->livein_blocks); | |
1685 | free (entry); | |
1686 | } | |
6de9cd9a | 1687 | |
6de9cd9a | 1688 | |
7256233c | 1689 | /* Callback for htab_traverse to dump the DEF_BLOCKS hash table. */ |
6de9cd9a | 1690 | |
7256233c | 1691 | static int |
38635499 | 1692 | debug_def_blocks_r (void **slot, void *data) |
7256233c | 1693 | { |
38635499 | 1694 | FILE *file = (FILE *) data; |
7256233c | 1695 | struct def_blocks_d *db_p = (struct def_blocks_d *) *slot; |
b8698a0f | 1696 | |
38635499 DN |
1697 | fprintf (file, "VAR: "); |
1698 | print_generic_expr (file, db_p->var, dump_flags); | |
1699 | bitmap_print (file, db_p->def_blocks, ", DEF_BLOCKS: { ", "}"); | |
1700 | bitmap_print (file, db_p->livein_blocks, ", LIVEIN_BLOCKS: { ", "}"); | |
1701 | bitmap_print (file, db_p->phi_blocks, ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1702 | |
7256233c DN |
1703 | return 1; |
1704 | } | |
6de9cd9a | 1705 | |
6de9cd9a | 1706 | |
38635499 DN |
1707 | /* Dump the DEF_BLOCKS hash table on FILE. */ |
1708 | ||
1709 | void | |
1710 | dump_def_blocks (FILE *file) | |
1711 | { | |
1712 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
1713 | if (def_blocks) | |
1714 | htab_traverse (def_blocks, debug_def_blocks_r, file); | |
1715 | } | |
1716 | ||
1717 | ||
7256233c | 1718 | /* Dump the DEF_BLOCKS hash table on stderr. */ |
6de9cd9a | 1719 | |
7256233c DN |
1720 | void |
1721 | debug_def_blocks (void) | |
1722 | { | |
38635499 | 1723 | dump_def_blocks (stderr); |
7256233c | 1724 | } |
6de9cd9a | 1725 | |
5f240ec4 | 1726 | |
0bca51f0 | 1727 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1728 | |
0bca51f0 DN |
1729 | static inline void |
1730 | register_new_update_single (tree new_name, tree old_name) | |
1731 | { | |
1732 | tree currdef = get_current_def (old_name); | |
5f240ec4 | 1733 | |
38635499 | 1734 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1735 | This stack is later used by the dominator tree callbacks to |
1736 | restore the reaching definitions for all the variables | |
1737 | defined in the block after a recursive visit to all its | |
1738 | immediately dominated blocks. */ | |
d4e6fecb NS |
1739 | VEC_reserve (tree, heap, block_defs_stack, 2); |
1740 | VEC_quick_push (tree, block_defs_stack, currdef); | |
1741 | VEC_quick_push (tree, block_defs_stack, old_name); | |
5f240ec4 | 1742 | |
0bca51f0 DN |
1743 | /* Set the current reaching definition for OLD_NAME to be |
1744 | NEW_NAME. */ | |
1745 | set_current_def (old_name, new_name); | |
1746 | } | |
7256233c | 1747 | |
6de9cd9a | 1748 | |
0bca51f0 DN |
1749 | /* Register NEW_NAME to be the new reaching definition for all the |
1750 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1751 | replace old SSA names with new ones. */ | |
7256233c | 1752 | |
0bca51f0 DN |
1753 | static inline void |
1754 | register_new_update_set (tree new_name, bitmap old_names) | |
1755 | { | |
1756 | bitmap_iterator bi; | |
1757 | unsigned i; | |
7256233c | 1758 | |
0bca51f0 DN |
1759 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1760 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1761 | } |
1762 | ||
7256233c | 1763 | |
0bca51f0 | 1764 | |
84d65814 DN |
1765 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1766 | it is a symbol marked for renaming, replace it with USE_P's current | |
1767 | reaching definition. */ | |
1768 | ||
1769 | static inline void | |
1770 | maybe_replace_use (use_operand_p use_p) | |
1771 | { | |
1772 | tree rdef = NULL_TREE; | |
1773 | tree use = USE_FROM_PTR (use_p); | |
1774 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1775 | ||
1776 | if (symbol_marked_for_renaming (sym)) | |
1777 | rdef = get_reaching_def (sym); | |
1778 | else if (is_old_name (use)) | |
1779 | rdef = get_reaching_def (use); | |
1780 | ||
1781 | if (rdef && rdef != use) | |
1782 | SET_USE (use_p, rdef); | |
1783 | } | |
1784 | ||
1785 | ||
b5b8b0ac AO |
1786 | /* Same as maybe_replace_use, but without introducing default stmts, |
1787 | returning false to indicate a need to do so. */ | |
1788 | ||
1789 | static inline bool | |
1790 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1791 | { | |
1792 | tree rdef = NULL_TREE; | |
1793 | tree use = USE_FROM_PTR (use_p); | |
1794 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1795 | ||
1796 | if (symbol_marked_for_renaming (sym)) | |
1797 | rdef = get_current_def (sym); | |
1798 | else if (is_old_name (use)) | |
1799 | { | |
1800 | rdef = get_current_def (use); | |
1801 | /* We can't assume that, if there's no current definition, the | |
1802 | default one should be used. It could be the case that we've | |
1803 | rearranged blocks so that the earlier definition no longer | |
1804 | dominates the use. */ | |
1805 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1806 | rdef = use; | |
1807 | } | |
1808 | else | |
1809 | rdef = use; | |
1810 | ||
1811 | if (rdef && rdef != use) | |
1812 | SET_USE (use_p, rdef); | |
1813 | ||
1814 | return rdef != NULL_TREE; | |
1815 | } | |
1816 | ||
1817 | ||
84d65814 DN |
1818 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1819 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1820 | register it as the current definition for the names replaced by | |
1821 | DEF_P. */ | |
1822 | ||
1823 | static inline void | |
3a56edc7 AO |
1824 | maybe_register_def (def_operand_p def_p, gimple stmt, |
1825 | gimple_stmt_iterator gsi) | |
84d65814 DN |
1826 | { |
1827 | tree def = DEF_FROM_PTR (def_p); | |
1828 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
1829 | ||
38635499 DN |
1830 | /* If DEF is a naked symbol that needs renaming, create a new |
1831 | name for it. */ | |
84d65814 DN |
1832 | if (symbol_marked_for_renaming (sym)) |
1833 | { | |
1834 | if (DECL_P (def)) | |
1835 | { | |
3a56edc7 AO |
1836 | tree tracked_var; |
1837 | ||
84d65814 DN |
1838 | def = make_ssa_name (def, stmt); |
1839 | SET_DEF (def_p, def); | |
3a56edc7 AO |
1840 | |
1841 | tracked_var = target_for_debug_bind (sym); | |
1842 | if (tracked_var) | |
1843 | { | |
1844 | gimple note = gimple_build_debug_bind (tracked_var, def, stmt); | |
1845 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
1846 | } | |
84d65814 DN |
1847 | } |
1848 | ||
1849 | register_new_update_single (def, sym); | |
1850 | } | |
1851 | else | |
1852 | { | |
1853 | /* If DEF is a new name, register it as a new definition | |
1854 | for all the names replaced by DEF. */ | |
1855 | if (is_new_name (def)) | |
1856 | register_new_update_set (def, names_replaced_by (def)); | |
1857 | ||
1858 | /* If DEF is an old name, register DEF as a new | |
1859 | definition for itself. */ | |
1860 | if (is_old_name (def)) | |
1861 | register_new_update_single (def, def); | |
1862 | } | |
1863 | } | |
1864 | ||
1865 | ||
0bca51f0 DN |
1866 | /* Update every variable used in the statement pointed-to by SI. The |
1867 | statement is assumed to be in SSA form already. Names in | |
1868 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1869 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1870 | will be registered as a new definition for their corresponding name | |
1871 | in OLD_SSA_NAMES. */ | |
1872 | ||
1873 | static void | |
3a56edc7 | 1874 | rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi) |
0bca51f0 | 1875 | { |
0bca51f0 DN |
1876 | use_operand_p use_p; |
1877 | def_operand_p def_p; | |
1878 | ssa_op_iter iter; | |
1879 | ||
0bca51f0 | 1880 | /* Only update marked statements. */ |
726a989a | 1881 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
0bca51f0 DN |
1882 | return; |
1883 | ||
1884 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1885 | { | |
1886 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 1887 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
1888 | fprintf (dump_file, "\n"); |
1889 | } | |
1890 | ||
1891 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1892 | symbol is marked for renaming. */ | |
726a989a | 1893 | if (rewrite_uses_p (stmt)) |
b5b8b0ac AO |
1894 | { |
1895 | if (is_gimple_debug (stmt)) | |
1896 | { | |
1897 | bool failed = false; | |
1898 | ||
1899 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1900 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
1901 | { | |
1902 | failed = true; | |
1903 | break; | |
1904 | } | |
1905 | ||
1906 | if (failed) | |
1907 | { | |
1908 | /* DOM sometimes threads jumps in such a way that a | |
1909 | debug stmt ends up referencing a SSA variable that no | |
1910 | longer dominates the debug stmt, but such that all | |
1911 | incoming definitions refer to the same definition in | |
1912 | an earlier dominator. We could try to recover that | |
1913 | definition somehow, but this will have to do for now. | |
1914 | ||
1915 | Introducing a default definition, which is what | |
1916 | maybe_replace_use() would do in such cases, may | |
1917 | modify code generation, for the otherwise-unused | |
1918 | default definition would never go away, modifying SSA | |
1919 | version numbers all over. */ | |
1920 | gimple_debug_bind_reset_value (stmt); | |
1921 | update_stmt (stmt); | |
1922 | } | |
1923 | } | |
1924 | else | |
1925 | { | |
1926 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
1927 | maybe_replace_use (use_p); | |
1928 | } | |
1929 | } | |
0bca51f0 DN |
1930 | |
1931 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
1932 | Also register definitions for names whose underlying symbol is | |
1933 | marked for renaming. */ | |
726a989a | 1934 | if (register_defs_p (stmt)) |
5006671f | 1935 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
3a56edc7 | 1936 | maybe_register_def (def_p, stmt, gsi); |
0bca51f0 DN |
1937 | } |
1938 | ||
1939 | ||
1940 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
1941 | every PHI node found, check if any of its arguments is in | |
1942 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
1943 | definition, replace it. */ | |
1944 | ||
1945 | static void | |
ccf5c864 | 1946 | rewrite_update_phi_arguments (basic_block bb) |
0bca51f0 DN |
1947 | { |
1948 | edge e; | |
1949 | edge_iterator ei; | |
2ce79879 | 1950 | unsigned i; |
0bca51f0 DN |
1951 | |
1952 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1953 | { | |
726a989a RB |
1954 | gimple phi; |
1955 | gimple_vec phis; | |
0bca51f0 | 1956 | |
2ce79879 ZD |
1957 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
1958 | continue; | |
b8698a0f | 1959 | |
726a989a RB |
1960 | phis = VEC_index (gimple_vec, phis_to_rewrite, e->dest->index); |
1961 | for (i = 0; VEC_iterate (gimple, phis, i, phi); i++) | |
0bca51f0 | 1962 | { |
f5045c96 | 1963 | tree arg, lhs_sym, reaching_def = NULL; |
0bca51f0 DN |
1964 | use_operand_p arg_p; |
1965 | ||
726a989a | 1966 | gcc_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
1967 | |
1968 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
1969 | arg = USE_FROM_PTR (arg_p); | |
1970 | ||
1971 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
1972 | continue; | |
1973 | ||
726a989a | 1974 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 1975 | |
0bca51f0 DN |
1976 | if (arg == NULL_TREE) |
1977 | { | |
1978 | /* When updating a PHI node for a recently introduced | |
1979 | symbol we may find NULL arguments. That's why we | |
1980 | take the symbol from the LHS of the PHI node. */ | |
f5045c96 AM |
1981 | reaching_def = get_reaching_def (lhs_sym); |
1982 | ||
0bca51f0 DN |
1983 | } |
1984 | else | |
1985 | { | |
1986 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
1987 | ||
1988 | if (symbol_marked_for_renaming (sym)) | |
f5045c96 | 1989 | reaching_def = get_reaching_def (sym); |
0bca51f0 | 1990 | else if (is_old_name (arg)) |
f5045c96 AM |
1991 | reaching_def = get_reaching_def (arg); |
1992 | } | |
1993 | ||
1994 | /* Update the argument if there is a reaching def. */ | |
1995 | if (reaching_def) | |
1996 | { | |
1997 | gimple stmt; | |
1998 | source_location locus; | |
1999 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2000 | ||
2001 | SET_USE (arg_p, reaching_def); | |
2002 | stmt = SSA_NAME_DEF_STMT (reaching_def); | |
2003 | ||
b8698a0f | 2004 | /* Single element PHI nodes behave like copies, so get the |
f5045c96 | 2005 | location from the phi argument. */ |
b8698a0f | 2006 | if (gimple_code (stmt) == GIMPLE_PHI && |
f5045c96 AM |
2007 | gimple_phi_num_args (stmt) == 1) |
2008 | locus = gimple_phi_arg_location (stmt, 0); | |
2009 | else | |
2010 | locus = gimple_location (stmt); | |
2011 | ||
2012 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
0bca51f0 DN |
2013 | } |
2014 | ||
f5045c96 | 2015 | |
0bca51f0 DN |
2016 | if (e->flags & EDGE_ABNORMAL) |
2017 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2018 | } | |
2019 | } | |
2020 | } | |
2021 | ||
2022 | ||
ccf5c864 PB |
2023 | /* Initialization of block data structures for the incremental SSA |
2024 | update pass. Create a block local stack of reaching definitions | |
2025 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2026 | new definitions for every PHI node in the block. */ | |
2027 | ||
2028 | static void | |
2029 | rewrite_update_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2030 | basic_block bb) | |
2031 | { | |
2032 | edge e; | |
2033 | edge_iterator ei; | |
2034 | bool is_abnormal_phi; | |
2035 | gimple_stmt_iterator gsi; | |
2036 | ||
2037 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2038 | fprintf (dump_file, "\n\nRegistering new PHI nodes in block #%d\n\n", | |
2039 | bb->index); | |
2040 | ||
2041 | /* Mark the unwind point for this block. */ | |
2042 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
2043 | ||
2044 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
2045 | return; | |
2046 | ||
2047 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2048 | edge. */ | |
2049 | is_abnormal_phi = false; | |
2050 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2051 | if (e->flags & EDGE_ABNORMAL) | |
2052 | { | |
2053 | is_abnormal_phi = true; | |
2054 | break; | |
2055 | } | |
2056 | ||
2057 | /* If any of the PHI nodes is a replacement for a name in | |
2058 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2059 | register it as a new definition for its corresponding name. Also | |
2060 | register definitions for names whose underlying symbols are | |
2061 | marked for renaming. */ | |
2062 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2063 | { | |
2064 | tree lhs, lhs_sym; | |
2065 | gimple phi = gsi_stmt (gsi); | |
2066 | ||
2067 | if (!register_defs_p (phi)) | |
2068 | continue; | |
b8698a0f | 2069 | |
ccf5c864 PB |
2070 | lhs = gimple_phi_result (phi); |
2071 | lhs_sym = SSA_NAME_VAR (lhs); | |
2072 | ||
2073 | if (symbol_marked_for_renaming (lhs_sym)) | |
2074 | register_new_update_single (lhs, lhs_sym); | |
2075 | else | |
2076 | { | |
2077 | ||
2078 | /* If LHS is a new name, register a new definition for all | |
2079 | the names replaced by LHS. */ | |
2080 | if (is_new_name (lhs)) | |
2081 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
b8698a0f | 2082 | |
ccf5c864 PB |
2083 | /* If LHS is an OLD name, register it as a new definition |
2084 | for itself. */ | |
2085 | if (is_old_name (lhs)) | |
2086 | register_new_update_single (lhs, lhs); | |
2087 | } | |
2088 | ||
2089 | if (is_abnormal_phi) | |
2090 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2091 | } | |
2092 | ||
2093 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
2094 | if (TEST_BIT (interesting_blocks, bb->index)) | |
3a56edc7 AO |
2095 | { |
2096 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); | |
ccf5c864 | 2097 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
3a56edc7 AO |
2098 | rewrite_update_stmt (gsi_stmt (gsi), gsi); |
2099 | } | |
ccf5c864 PB |
2100 | |
2101 | /* Step 3. Update PHI nodes. */ | |
2102 | rewrite_update_phi_arguments (bb); | |
2103 | } | |
2104 | ||
2105 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2106 | the current reaching definition of every name re-written in BB to | |
2107 | the original reaching definition before visiting BB. This | |
2108 | unwinding must be done in the opposite order to what is done in | |
2109 | register_new_update_set. */ | |
2110 | ||
2111 | static void | |
2112 | rewrite_update_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2113 | basic_block bb ATTRIBUTE_UNUSED) | |
2114 | { | |
2115 | while (VEC_length (tree, block_defs_stack) > 0) | |
2116 | { | |
2117 | tree var = VEC_pop (tree, block_defs_stack); | |
2118 | tree saved_def; | |
b8698a0f | 2119 | |
ccf5c864 PB |
2120 | /* NULL indicates the unwind stop point for this block (see |
2121 | rewrite_update_enter_block). */ | |
2122 | if (var == NULL) | |
2123 | return; | |
2124 | ||
2125 | saved_def = VEC_pop (tree, block_defs_stack); | |
2126 | set_current_def (var, saved_def); | |
2127 | } | |
2128 | } | |
2129 | ||
2130 | ||
0bca51f0 | 2131 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
b8698a0f | 2132 | form. |
0bca51f0 DN |
2133 | |
2134 | ENTRY indicates the block where to start. Every block dominated by | |
2135 | ENTRY will be rewritten. | |
2136 | ||
2137 | WHAT indicates what actions will be taken by the renamer (see enum | |
2138 | rewrite_mode). | |
2139 | ||
2140 | BLOCKS are the set of interesting blocks for the dominator walker | |
2141 | to process. If this set is NULL, then all the nodes dominated | |
2142 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2143 | are not present in BLOCKS are ignored. */ | |
2144 | ||
2145 | static void | |
ccf5c864 | 2146 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
0bca51f0 DN |
2147 | { |
2148 | struct dom_walk_data walk_data; | |
b8698a0f | 2149 | |
0bca51f0 DN |
2150 | /* Rewrite all the basic blocks in the program. */ |
2151 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2152 | ||
2153 | /* Setup callbacks for the generic dominator tree walker. */ | |
2154 | memset (&walk_data, 0, sizeof (walk_data)); | |
2155 | ||
2156 | walk_data.dom_direction = CDI_DOMINATORS; | |
0bca51f0 DN |
2157 | |
2158 | if (what == REWRITE_ALL) | |
ccf5c864 PB |
2159 | { |
2160 | walk_data.before_dom_children = rewrite_enter_block; | |
2161 | walk_data.after_dom_children = rewrite_leave_block; | |
2162 | } | |
0bca51f0 | 2163 | else if (what == REWRITE_UPDATE) |
ccf5c864 PB |
2164 | { |
2165 | walk_data.before_dom_children = rewrite_update_enter_block; | |
2166 | walk_data.after_dom_children = rewrite_update_leave_block; | |
2167 | } | |
0bca51f0 DN |
2168 | else |
2169 | gcc_unreachable (); | |
2170 | ||
d4e6fecb | 2171 | block_defs_stack = VEC_alloc (tree, heap, 10); |
0bca51f0 DN |
2172 | |
2173 | /* Initialize the dominator walker. */ | |
2174 | init_walk_dominator_tree (&walk_data); | |
2175 | ||
2176 | /* Recursively walk the dominator tree rewriting each statement in | |
2177 | each basic block. */ | |
2178 | walk_dominator_tree (&walk_data, entry); | |
2179 | ||
2180 | /* Finalize the dominator walker. */ | |
2181 | fini_walk_dominator_tree (&walk_data); | |
2182 | ||
2183 | /* Debugging dumps. */ | |
2184 | if (dump_file && (dump_flags & TDF_STATS)) | |
2185 | { | |
2186 | dump_dfa_stats (dump_file); | |
2187 | if (def_blocks) | |
2188 | dump_tree_ssa_stats (dump_file); | |
2189 | } | |
b8698a0f | 2190 | |
d4e6fecb | 2191 | VEC_free (tree, heap, block_defs_stack); |
0bca51f0 DN |
2192 | |
2193 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2194 | } | |
2195 | ||
2196 | ||
ccf5c864 PB |
2197 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2198 | at the start of each block, and call mark_def_sites for each statement. */ | |
6de9cd9a | 2199 | |
5f240ec4 | 2200 | static void |
ccf5c864 | 2201 | mark_def_sites_block (struct dom_walk_data *walk_data, basic_block bb) |
5f240ec4 | 2202 | { |
38635499 | 2203 | struct mark_def_sites_global_data *gd; |
ccf5c864 PB |
2204 | bitmap kills; |
2205 | gimple_stmt_iterator gsi; | |
2206 | ||
38635499 | 2207 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; |
ccf5c864 PB |
2208 | kills = gd->kills; |
2209 | ||
2210 | bitmap_clear (kills); | |
2211 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2212 | mark_def_sites (bb, gsi_stmt (gsi), kills); | |
7256233c | 2213 | } |
5f240ec4 | 2214 | |
5f240ec4 | 2215 | |
0bca51f0 DN |
2216 | /* Mark the definition site blocks for each variable, so that we know |
2217 | where the variable is actually live. | |
2218 | ||
ccf5c864 PB |
2219 | The INTERESTING_BLOCKS global will be filled in with all the blocks |
2220 | that should be processed by the renamer. It is assumed that the | |
2221 | caller has already initialized and zeroed it. */ | |
5f240ec4 | 2222 | |
0bca51f0 | 2223 | static void |
ccf5c864 | 2224 | mark_def_site_blocks (void) |
7256233c | 2225 | { |
7256233c DN |
2226 | struct dom_walk_data walk_data; |
2227 | struct mark_def_sites_global_data mark_def_sites_global_data; | |
5f240ec4 | 2228 | |
7256233c DN |
2229 | /* Setup callbacks for the generic dominator tree walker to find and |
2230 | mark definition sites. */ | |
7256233c DN |
2231 | walk_data.dom_direction = CDI_DOMINATORS; |
2232 | walk_data.initialize_block_local_data = NULL; | |
ccf5c864 PB |
2233 | walk_data.before_dom_children = mark_def_sites_block; |
2234 | walk_data.after_dom_children = NULL; | |
5f240ec4 | 2235 | |
7256233c DN |
2236 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2237 | large enough to accommodate all the variables referenced in the | |
2238 | function, not just the ones we are renaming. */ | |
2239 | mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); | |
2240 | walk_data.global_data = &mark_def_sites_global_data; | |
6de9cd9a | 2241 | |
7256233c DN |
2242 | /* We do not have any local data. */ |
2243 | walk_data.block_local_data_size = 0; | |
2244 | ||
2245 | /* Initialize the dominator walker. */ | |
2246 | init_walk_dominator_tree (&walk_data); | |
2247 | ||
2248 | /* Recursively walk the dominator tree. */ | |
2249 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
2250 | ||
2251 | /* Finalize the dominator walker. */ | |
2252 | fini_walk_dominator_tree (&walk_data); | |
2253 | ||
2254 | /* We no longer need this bitmap, clear and free it. */ | |
2255 | BITMAP_FREE (mark_def_sites_global_data.kills); | |
6de9cd9a DN |
2256 | } |
2257 | ||
6de9cd9a | 2258 | |
38635499 DN |
2259 | /* Initialize internal data needed during renaming. */ |
2260 | ||
2261 | static void | |
2262 | init_ssa_renamer (void) | |
2263 | { | |
2264 | tree var; | |
2265 | referenced_var_iterator rvi; | |
2266 | ||
2267 | cfun->gimple_df->in_ssa_p = false; | |
2268 | ||
2269 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
2270 | gcc_assert (def_blocks == NULL); | |
2271 | def_blocks = htab_create (num_referenced_vars, def_blocks_hash, | |
2272 | def_blocks_eq, def_blocks_free); | |
2273 | ||
2274 | FOR_EACH_REFERENCED_VAR(var, rvi) | |
2275 | set_current_def (var, NULL_TREE); | |
2276 | } | |
2277 | ||
2278 | ||
2279 | /* Deallocate internal data structures used by the renamer. */ | |
2280 | ||
2281 | static void | |
2282 | fini_ssa_renamer (void) | |
2283 | { | |
2284 | if (def_blocks) | |
2285 | { | |
2286 | htab_delete (def_blocks); | |
2287 | def_blocks = NULL; | |
2288 | } | |
2289 | ||
2290 | cfun->gimple_df->in_ssa_p = true; | |
2291 | } | |
2292 | ||
7256233c | 2293 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2294 | proceeds in four main phases: |
6de9cd9a | 2295 | |
0bca51f0 DN |
2296 | 1- Compute dominance frontier and immediate dominators, needed to |
2297 | insert PHI nodes and rename the function in dominator tree | |
2298 | order. | |
6de9cd9a | 2299 | |
0bca51f0 | 2300 | 2- Find and mark all the blocks that define variables |
7256233c | 2301 | (mark_def_site_blocks). |
6de9cd9a | 2302 | |
0bca51f0 | 2303 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2304 | |
0bca51f0 | 2305 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2306 | |
77bfa778 | 2307 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2308 | (walk_dominator_tree). */ |
7256233c | 2309 | |
c2924966 | 2310 | static unsigned int |
0bca51f0 | 2311 | rewrite_into_ssa (void) |
6de9cd9a | 2312 | { |
7256233c DN |
2313 | bitmap *dfs; |
2314 | basic_block bb; | |
b8698a0f | 2315 | |
7256233c | 2316 | timevar_push (TV_TREE_SSA_OTHER); |
6de9cd9a | 2317 | |
0bca51f0 DN |
2318 | /* Initialize operand data structures. */ |
2319 | init_ssa_operands (); | |
6de9cd9a | 2320 | |
38635499 DN |
2321 | /* Initialize internal data needed by the renamer. */ |
2322 | init_ssa_renamer (); | |
2323 | ||
0bca51f0 DN |
2324 | /* Initialize the set of interesting blocks. The callback |
2325 | mark_def_sites will add to this set those blocks that the renamer | |
2326 | should process. */ | |
2327 | interesting_blocks = sbitmap_alloc (last_basic_block); | |
2328 | sbitmap_zero (interesting_blocks); | |
6de9cd9a | 2329 | |
af5d3a18 | 2330 | /* Initialize dominance frontier. */ |
38635499 | 2331 | dfs = XNEWVEC (bitmap, last_basic_block); |
7256233c DN |
2332 | FOR_EACH_BB (bb) |
2333 | dfs[bb->index] = BITMAP_ALLOC (NULL); | |
6de9cd9a | 2334 | |
0bca51f0 DN |
2335 | /* 1- Compute dominance frontiers. */ |
2336 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2337 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2338 | |
0bca51f0 | 2339 | /* 2- Find and mark definition sites. */ |
ccf5c864 | 2340 | mark_def_site_blocks (); |
0bca51f0 DN |
2341 | |
2342 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2343 | insert_phi_nodes (dfs); |
6de9cd9a | 2344 | |
0bca51f0 | 2345 | /* 4- Rename all the blocks. */ |
ccf5c864 | 2346 | rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL); |
6de9cd9a | 2347 | |
7256233c DN |
2348 | /* Free allocated memory. */ |
2349 | FOR_EACH_BB (bb) | |
2350 | BITMAP_FREE (dfs[bb->index]); | |
2351 | free (dfs); | |
6de9cd9a | 2352 | |
b5dcb2b9 JL |
2353 | sbitmap_free (interesting_blocks); |
2354 | ||
38635499 DN |
2355 | fini_ssa_renamer (); |
2356 | ||
7256233c | 2357 | timevar_pop (TV_TREE_SSA_OTHER); |
c2924966 | 2358 | return 0; |
6de9cd9a DN |
2359 | } |
2360 | ||
2361 | ||
b8698a0f | 2362 | struct gimple_opt_pass pass_build_ssa = |
6de9cd9a | 2363 | { |
8ddbbcae JH |
2364 | { |
2365 | GIMPLE_PASS, | |
7256233c DN |
2366 | "ssa", /* name */ |
2367 | NULL, /* gate */ | |
0bca51f0 | 2368 | rewrite_into_ssa, /* execute */ |
7256233c DN |
2369 | NULL, /* sub */ |
2370 | NULL, /* next */ | |
2371 | 0, /* static_pass_number */ | |
7072a650 | 2372 | TV_NONE, /* tv_id */ |
7256233c DN |
2373 | PROP_cfg | PROP_referenced_vars, /* properties_required */ |
2374 | PROP_ssa, /* properties_provided */ | |
2375 | 0, /* properties_destroyed */ | |
2376 | 0, /* todo_flags_start */ | |
3f519b35 | 2377 | TODO_dump_func |
5006671f | 2378 | | TODO_update_ssa_only_virtuals |
3f519b35 | 2379 | | TODO_verify_ssa |
8ddbbcae JH |
2380 | | TODO_remove_unused_locals /* todo_flags_finish */ |
2381 | } | |
7256233c | 2382 | }; |
6de9cd9a DN |
2383 | |
2384 | ||
0bca51f0 DN |
2385 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2386 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2387 | |
0bca51f0 | 2388 | static void |
726a989a | 2389 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
6de9cd9a | 2390 | { |
95dd3097 | 2391 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2392 | set_register_defs (stmt, true); |
0bca51f0 DN |
2393 | |
2394 | if (insert_phi_p) | |
2395 | { | |
726a989a | 2396 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2397 | |
0bca51f0 DN |
2398 | set_def_block (var, bb, is_phi_p); |
2399 | ||
2400 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2401 | site for both itself and all the old names replaced by it. */ | |
2402 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2403 | { | |
2404 | bitmap_iterator bi; | |
2405 | unsigned i; | |
2406 | bitmap set = names_replaced_by (var); | |
2407 | if (set) | |
2408 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2409 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2410 | } | |
2411 | } | |
2412 | } | |
2413 | ||
2414 | ||
2415 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2416 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2417 | nodes. */ |
0bca51f0 DN |
2418 | |
2419 | static inline void | |
726a989a | 2420 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
0bca51f0 | 2421 | { |
726a989a | 2422 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2423 | |
95dd3097 ZD |
2424 | mark_block_for_update (def_bb); |
2425 | mark_block_for_update (bb); | |
2426 | ||
726a989a | 2427 | if (gimple_code (stmt) == GIMPLE_PHI) |
2ce79879 ZD |
2428 | mark_phi_for_rewrite (def_bb, stmt); |
2429 | else | |
b5b8b0ac AO |
2430 | { |
2431 | set_rewrite_uses (stmt, true); | |
2432 | ||
2433 | if (is_gimple_debug (stmt)) | |
2434 | return; | |
2435 | } | |
0bca51f0 DN |
2436 | |
2437 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2438 | to BB. Note that we cannot just use the block holding VAR's | |
2439 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2440 | it will have several definitions (itself and all the names that | |
2441 | replace it). */ | |
2442 | if (insert_phi_p) | |
2443 | { | |
84d65814 | 2444 | struct def_blocks_d *db_p = get_def_blocks_for (var); |
0bca51f0 DN |
2445 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2446 | set_livein_block (var, bb); | |
2447 | } | |
2448 | } | |
2449 | ||
2450 | ||
0bca51f0 | 2451 | /* Do a dominator walk starting at BB processing statements that |
84d65814 DN |
2452 | reference symbols in SYMS_TO_RENAME. This is very similar to |
2453 | mark_def_sites, but the scan handles statements whose operands may | |
95dd3097 | 2454 | already be SSA names. |
0bca51f0 | 2455 | |
84d65814 DN |
2456 | If INSERT_PHI_P is true, mark those uses as live in the |
2457 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2458 | algorithm to make PHI pruning decisions. |
2459 | ||
2460 | FIXME. Most of this would be unnecessary if we could associate a | |
2461 | symbol to all the SSA names that reference it. But that | |
2462 | sounds like it would be expensive to maintain. Still, it | |
2463 | would be interesting to see if it makes better sense to do | |
2464 | that. */ | |
0bca51f0 DN |
2465 | |
2466 | static void | |
95dd3097 | 2467 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2468 | { |
2469 | basic_block son; | |
726a989a | 2470 | gimple_stmt_iterator si; |
f074ff6c ZD |
2471 | edge e; |
2472 | edge_iterator ei; | |
0bca51f0 | 2473 | |
95dd3097 ZD |
2474 | mark_block_for_update (bb); |
2475 | ||
0bca51f0 | 2476 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2477 | the symbols that we are interested in. */ |
726a989a | 2478 | for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2479 | { |
726a989a RB |
2480 | gimple phi = gsi_stmt (si); |
2481 | tree lhs_sym, lhs = gimple_phi_result (phi); | |
0bca51f0 | 2482 | |
0bca51f0 DN |
2483 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
2484 | ||
f074ff6c ZD |
2485 | if (!symbol_marked_for_renaming (lhs_sym)) |
2486 | continue; | |
726a989a | 2487 | |
f074ff6c ZD |
2488 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2489 | ||
2490 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2491 | to process the arguments of the phi nodes of the successor edges of | |
2492 | BB at the end of prepare_block_for_update, however, that turns out | |
2493 | to be significantly more expensive. Doing it here is conservatively | |
2494 | correct -- it may only cause us to believe a value to be live in a | |
2495 | block that also contains its definition, and thus insert a few more | |
2496 | phi nodes for it. */ | |
2497 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2498 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2499 | } |
2500 | ||
2501 | /* Process the statements. */ | |
726a989a | 2502 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2503 | { |
726a989a | 2504 | gimple stmt; |
0bca51f0 DN |
2505 | ssa_op_iter i; |
2506 | use_operand_p use_p; | |
2507 | def_operand_p def_p; | |
b8698a0f | 2508 | |
726a989a | 2509 | stmt = gsi_stmt (si); |
0bca51f0 | 2510 | |
38635499 | 2511 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) |
0bca51f0 DN |
2512 | { |
2513 | tree use = USE_FROM_PTR (use_p); | |
2514 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
84d65814 | 2515 | if (symbol_marked_for_renaming (sym)) |
38635499 | 2516 | mark_use_interesting (sym, stmt, bb, insert_phi_p); |
0bca51f0 DN |
2517 | } |
2518 | ||
38635499 | 2519 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
2520 | { |
2521 | tree def = DEF_FROM_PTR (def_p); | |
2522 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
0bca51f0 | 2523 | if (symbol_marked_for_renaming (sym)) |
38635499 | 2524 | mark_def_interesting (sym, stmt, bb, insert_phi_p); |
0bca51f0 DN |
2525 | } |
2526 | } | |
2527 | ||
2528 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2529 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2530 | son; |
2531 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2532 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2533 | } |
2534 | ||
2535 | ||
2536 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2537 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2538 | prepare_names_to_update. */ | |
2539 | ||
2540 | static void | |
95dd3097 | 2541 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2542 | { |
2543 | use_operand_p use_p; | |
2544 | imm_use_iterator iter; | |
2545 | ||
2546 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2547 | { | |
726a989a RB |
2548 | gimple stmt = USE_STMT (use_p); |
2549 | basic_block bb = gimple_bb (stmt); | |
84d65814 | 2550 | |
726a989a | 2551 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2552 | { |
f074ff6c | 2553 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
726a989a | 2554 | edge e = gimple_phi_arg_edge (stmt, ix); |
f074ff6c | 2555 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2556 | } |
2557 | else | |
2558 | { | |
2559 | /* For regular statements, mark this as an interesting use | |
2560 | for NAME. */ | |
95dd3097 | 2561 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2562 | } |
2563 | } | |
0bca51f0 DN |
2564 | } |
2565 | ||
2566 | ||
84d65814 DN |
2567 | /* Helper for prepare_names_to_update. Mark the definition site for |
2568 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2569 | prepare_names_to_update. */ | |
0bca51f0 DN |
2570 | |
2571 | static void | |
95dd3097 | 2572 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2573 | { |
726a989a | 2574 | gimple stmt; |
0bca51f0 DN |
2575 | basic_block bb; |
2576 | ||
0bca51f0 DN |
2577 | gcc_assert (names_to_release == NULL |
2578 | || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name))); | |
2579 | ||
2580 | stmt = SSA_NAME_DEF_STMT (name); | |
726a989a | 2581 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2582 | if (bb) |
2583 | { | |
2584 | gcc_assert (bb->index < last_basic_block); | |
95dd3097 ZD |
2585 | mark_block_for_update (bb); |
2586 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2587 | } |
2588 | } | |
2589 | ||
2590 | ||
84d65814 | 2591 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2592 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2593 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2594 | |
2595 | static void | |
95dd3097 | 2596 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2597 | { |
dfea6c85 | 2598 | unsigned i = 0; |
0bca51f0 | 2599 | bitmap_iterator bi; |
b6e7e9af | 2600 | sbitmap_iterator sbi; |
0bca51f0 DN |
2601 | |
2602 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2603 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2604 | defining basic block (which most likely doesn't exist). Notice | |
2605 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2606 | want to replace existing instances. */ | |
2607 | if (names_to_release) | |
2608 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2609 | RESET_BIT (new_ssa_names, i); | |
2610 | ||
84d65814 DN |
2611 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2612 | names may be considered to be live-in on blocks that contain | |
2613 | definitions for their replacements. */ | |
b6e7e9af | 2614 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2615 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2616 | |
0bca51f0 DN |
2617 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2618 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
b6e7e9af | 2619 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2620 | { |
2621 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2622 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2623 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2624 | } |
0bca51f0 DN |
2625 | } |
2626 | ||
2627 | ||
2628 | /* Dump all the names replaced by NAME to FILE. */ | |
2629 | ||
2630 | void | |
2631 | dump_names_replaced_by (FILE *file, tree name) | |
2632 | { | |
2633 | unsigned i; | |
2634 | bitmap old_set; | |
2635 | bitmap_iterator bi; | |
2636 | ||
2637 | print_generic_expr (file, name, 0); | |
2638 | fprintf (file, " -> { "); | |
2639 | ||
2640 | old_set = names_replaced_by (name); | |
2641 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2642 | { | |
2643 | print_generic_expr (file, ssa_name (i), 0); | |
2644 | fprintf (file, " "); | |
2645 | } | |
2646 | ||
2647 | fprintf (file, "}\n"); | |
2648 | } | |
2649 | ||
2650 | ||
2651 | /* Dump all the names replaced by NAME to stderr. */ | |
2652 | ||
2653 | void | |
2654 | debug_names_replaced_by (tree name) | |
2655 | { | |
2656 | dump_names_replaced_by (stderr, name); | |
2657 | } | |
2658 | ||
2659 | ||
84d65814 | 2660 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2661 | |
2662 | void | |
84d65814 | 2663 | dump_update_ssa (FILE *file) |
0bca51f0 | 2664 | { |
dfea6c85 | 2665 | unsigned i = 0; |
0bca51f0 DN |
2666 | bitmap_iterator bi; |
2667 | ||
5006671f | 2668 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
2669 | return; |
2670 | ||
2671 | if (new_ssa_names && sbitmap_first_set_bit (new_ssa_names) >= 0) | |
2672 | { | |
b6e7e9af KH |
2673 | sbitmap_iterator sbi; |
2674 | ||
0bca51f0 DN |
2675 | fprintf (file, "\nSSA replacement table\n"); |
2676 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2677 | "O_1, ..., O_j\n\n"); | |
2678 | ||
b6e7e9af KH |
2679 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
2680 | dump_names_replaced_by (file, ssa_name (i)); | |
84d65814 DN |
2681 | |
2682 | fprintf (file, "\n"); | |
2683 | fprintf (file, "Number of virtual NEW -> OLD mappings: %7u\n", | |
2684 | update_ssa_stats.num_virtual_mappings); | |
2685 | fprintf (file, "Number of real NEW -> OLD mappings: %7u\n", | |
2686 | update_ssa_stats.num_total_mappings | |
2687 | - update_ssa_stats.num_virtual_mappings); | |
2688 | fprintf (file, "Number of total NEW -> OLD mappings: %7u\n", | |
2689 | update_ssa_stats.num_total_mappings); | |
2690 | ||
2691 | fprintf (file, "\nNumber of virtual symbols: %u\n", | |
2692 | update_ssa_stats.num_virtual_symbols); | |
0bca51f0 DN |
2693 | } |
2694 | ||
5006671f | 2695 | if (!bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
0bca51f0 DN |
2696 | { |
2697 | fprintf (file, "\n\nSymbols to be put in SSA form\n\n"); | |
5006671f RG |
2698 | dump_decl_set (file, SYMS_TO_RENAME (cfun)); |
2699 | fprintf (file, "\n"); | |
0bca51f0 DN |
2700 | } |
2701 | ||
0bca51f0 DN |
2702 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2703 | { | |
2704 | fprintf (file, "\n\nSSA names to release after updating the SSA web\n\n"); | |
2705 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2706 | { | |
2707 | print_generic_expr (file, ssa_name (i), 0); | |
2708 | fprintf (file, " "); | |
2709 | } | |
2710 | } | |
2711 | ||
2712 | fprintf (file, "\n\n"); | |
2713 | } | |
2714 | ||
2715 | ||
84d65814 | 2716 | /* Dump SSA update information to stderr. */ |
0bca51f0 DN |
2717 | |
2718 | void | |
84d65814 | 2719 | debug_update_ssa (void) |
0bca51f0 | 2720 | { |
84d65814 | 2721 | dump_update_ssa (stderr); |
0bca51f0 DN |
2722 | } |
2723 | ||
2724 | ||
2725 | /* Initialize data structures used for incremental SSA updates. */ | |
2726 | ||
2727 | static void | |
5006671f | 2728 | init_update_ssa (struct function *fn) |
0bca51f0 | 2729 | { |
84d65814 | 2730 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2731 | add_new_name_mapping are typically done after creating new SSA |
2732 | names, so we'll need to reallocate these arrays. */ | |
2733 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2734 | sbitmap_zero (old_ssa_names); | |
2735 | ||
2736 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2737 | sbitmap_zero (new_ssa_names); | |
2738 | ||
2739 | repl_tbl = htab_create (20, repl_map_hash, repl_map_eq, repl_map_free); | |
0bca51f0 | 2740 | names_to_release = NULL; |
84d65814 DN |
2741 | memset (&update_ssa_stats, 0, sizeof (update_ssa_stats)); |
2742 | update_ssa_stats.virtual_symbols = BITMAP_ALLOC (NULL); | |
5006671f | 2743 | update_ssa_initialized_fn = fn; |
0bca51f0 DN |
2744 | } |
2745 | ||
2746 | ||
2747 | /* Deallocate data structures used for incremental SSA updates. */ | |
2748 | ||
84d65814 | 2749 | void |
0bca51f0 DN |
2750 | delete_update_ssa (void) |
2751 | { | |
2752 | unsigned i; | |
2753 | bitmap_iterator bi; | |
2754 | ||
2755 | sbitmap_free (old_ssa_names); | |
2756 | old_ssa_names = NULL; | |
2757 | ||
2758 | sbitmap_free (new_ssa_names); | |
2759 | new_ssa_names = NULL; | |
2760 | ||
2761 | htab_delete (repl_tbl); | |
2762 | repl_tbl = NULL; | |
2763 | ||
5006671f | 2764 | bitmap_clear (SYMS_TO_RENAME (update_ssa_initialized_fn)); |
84d65814 | 2765 | BITMAP_FREE (update_ssa_stats.virtual_symbols); |
0bca51f0 DN |
2766 | |
2767 | if (names_to_release) | |
2768 | { | |
2769 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2770 | release_ssa_name (ssa_name (i)); | |
2771 | BITMAP_FREE (names_to_release); | |
2772 | } | |
2773 | ||
95dd3097 | 2774 | clear_ssa_name_info (); |
38635499 DN |
2775 | |
2776 | fini_ssa_renamer (); | |
2777 | ||
2778 | if (blocks_with_phis_to_rewrite) | |
2779 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2780 | { | |
726a989a | 2781 | gimple_vec phis = VEC_index (gimple_vec, phis_to_rewrite, i); |
38635499 | 2782 | |
726a989a RB |
2783 | VEC_free (gimple, heap, phis); |
2784 | VEC_replace (gimple_vec, phis_to_rewrite, i, NULL); | |
38635499 DN |
2785 | } |
2786 | ||
2787 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2788 | BITMAP_FREE (blocks_to_update); | |
5006671f | 2789 | update_ssa_initialized_fn = NULL; |
0bca51f0 DN |
2790 | } |
2791 | ||
2792 | ||
2793 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
2794 | operand pointed to by DEF_P with the newly created name. Return | |
2795 | the new name and register the replacement mapping <NEW, OLD> in | |
2796 | update_ssa's tables. */ | |
2797 | ||
2798 | tree | |
726a989a | 2799 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
0bca51f0 DN |
2800 | { |
2801 | tree new_name = duplicate_ssa_name (old_name, stmt); | |
2802 | ||
2803 | SET_DEF (def, new_name); | |
2804 | ||
726a989a | 2805 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 DN |
2806 | { |
2807 | edge e; | |
2808 | edge_iterator ei; | |
726a989a | 2809 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2810 | |
2811 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
2812 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2813 | if (e->flags & EDGE_ABNORMAL) | |
2814 | { | |
2815 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = 1; | |
2816 | break; | |
2817 | } | |
2818 | } | |
2819 | ||
2820 | register_new_name_mapping (new_name, old_name); | |
2821 | ||
2822 | /* For the benefit of passes that will be updating the SSA form on | |
2823 | their own, set the current reaching definition of OLD_NAME to be | |
2824 | NEW_NAME. */ | |
2825 | set_current_def (old_name, new_name); | |
2826 | ||
2827 | return new_name; | |
2828 | } | |
2829 | ||
2830 | ||
2831 | /* Register name NEW to be a replacement for name OLD. This function | |
2832 | must be called for every replacement that should be performed by | |
2833 | update_ssa. */ | |
2834 | ||
2835 | void | |
5006671f | 2836 | register_new_name_mapping (tree new_tree, tree old) |
0bca51f0 | 2837 | { |
5006671f RG |
2838 | if (!update_ssa_initialized_fn) |
2839 | init_update_ssa (cfun); | |
2840 | ||
2841 | gcc_assert (update_ssa_initialized_fn == cfun); | |
0bca51f0 | 2842 | |
5006671f | 2843 | add_new_name_mapping (new_tree, old); |
0bca51f0 DN |
2844 | } |
2845 | ||
2846 | ||
2847 | /* Register symbol SYM to be renamed by update_ssa. */ | |
2848 | ||
2849 | void | |
2850 | mark_sym_for_renaming (tree sym) | |
2851 | { | |
5006671f | 2852 | bitmap_set_bit (SYMS_TO_RENAME (cfun), DECL_UID (sym)); |
0bca51f0 DN |
2853 | } |
2854 | ||
2855 | ||
2856 | /* Register all the symbols in SET to be renamed by update_ssa. */ | |
2857 | ||
2858 | void | |
2859 | mark_set_for_renaming (bitmap set) | |
2860 | { | |
2861 | bitmap_iterator bi; | |
2862 | unsigned i; | |
2863 | ||
38635499 | 2864 | if (set == NULL || bitmap_empty_p (set)) |
84d65814 DN |
2865 | return; |
2866 | ||
0bca51f0 | 2867 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
38635499 | 2868 | mark_sym_for_renaming (referenced_var (i)); |
0bca51f0 DN |
2869 | } |
2870 | ||
2871 | ||
5006671f RG |
2872 | /* Return true if there is any work to be done by update_ssa |
2873 | for function FN. */ | |
0bca51f0 DN |
2874 | |
2875 | bool | |
5006671f | 2876 | need_ssa_update_p (struct function *fn) |
0bca51f0 | 2877 | { |
5006671f RG |
2878 | gcc_assert (fn != NULL); |
2879 | return (update_ssa_initialized_fn == fn | |
2880 | || (fn->gimple_df | |
2881 | && !bitmap_empty_p (SYMS_TO_RENAME (fn)))); | |
0bca51f0 DN |
2882 | } |
2883 | ||
8f8bb1d2 ZD |
2884 | /* Return true if SSA name mappings have been registered for SSA updating. */ |
2885 | ||
2886 | bool | |
2887 | name_mappings_registered_p (void) | |
2888 | { | |
5006671f RG |
2889 | if (!update_ssa_initialized_fn) |
2890 | return false; | |
2891 | ||
2892 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2893 | ||
8f8bb1d2 ZD |
2894 | return repl_tbl && htab_elements (repl_tbl) > 0; |
2895 | } | |
0bca51f0 DN |
2896 | |
2897 | /* Return true if name N has been registered in the replacement table. */ | |
2898 | ||
2899 | bool | |
726a989a | 2900 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 | 2901 | { |
5006671f | 2902 | if (!update_ssa_initialized_fn) |
0bca51f0 DN |
2903 | return false; |
2904 | ||
5006671f RG |
2905 | gcc_assert (update_ssa_initialized_fn == cfun); |
2906 | ||
2907 | return is_new_name (n) || is_old_name (n); | |
0bca51f0 DN |
2908 | } |
2909 | ||
2910 | ||
2911 | /* Return the set of all the SSA names marked to be replaced. */ | |
2912 | ||
2913 | bitmap | |
2914 | ssa_names_to_replace (void) | |
2915 | { | |
dfea6c85 | 2916 | unsigned i = 0; |
0bca51f0 | 2917 | bitmap ret; |
b6e7e9af | 2918 | sbitmap_iterator sbi; |
b8698a0f | 2919 | |
5006671f RG |
2920 | gcc_assert (update_ssa_initialized_fn == NULL |
2921 | || update_ssa_initialized_fn == cfun); | |
2922 | ||
0bca51f0 | 2923 | ret = BITMAP_ALLOC (NULL); |
b6e7e9af KH |
2924 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
2925 | bitmap_set_bit (ret, i); | |
0bca51f0 | 2926 | |
0bca51f0 DN |
2927 | return ret; |
2928 | } | |
2929 | ||
2930 | ||
2931 | /* Mark NAME to be released after update_ssa has finished. */ | |
2932 | ||
2933 | void | |
2934 | release_ssa_name_after_update_ssa (tree name) | |
2935 | { | |
5006671f | 2936 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
0bca51f0 DN |
2937 | |
2938 | if (names_to_release == NULL) | |
2939 | names_to_release = BITMAP_ALLOC (NULL); | |
2940 | ||
2941 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2942 | } | |
2943 | ||
2944 | ||
2945 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2946 | frontier information. BLOCKS is the set of blocks to be updated. | |
2947 | ||
2948 | This is slightly different than the regular PHI insertion | |
2949 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2950 | real names (i.e., GIMPLE registers) are inserted: | |
b8698a0f | 2951 | |
0bca51f0 DN |
2952 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
2953 | nodes inside the region affected by the block that defines VAR | |
2954 | and the blocks that define all its replacements. All these | |
84d65814 | 2955 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
2956 | |
2957 | First, we compute the entry point to the region (ENTRY). This is | |
2958 | given by the nearest common dominator to all the definition | |
2959 | blocks. When computing the iterated dominance frontier (IDF), any | |
2960 | block not strictly dominated by ENTRY is ignored. | |
2961 | ||
2962 | We then call the standard PHI insertion algorithm with the pruned | |
2963 | IDF. | |
2964 | ||
2965 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
2966 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
2967 | ||
2968 | static void | |
2969 | insert_updated_phi_nodes_for (tree var, bitmap *dfs, bitmap blocks, | |
2970 | unsigned update_flags) | |
2971 | { | |
2972 | basic_block entry; | |
2973 | struct def_blocks_d *db; | |
2974 | bitmap idf, pruned_idf; | |
2975 | bitmap_iterator bi; | |
2976 | unsigned i; | |
2977 | ||
2978 | #if defined ENABLE_CHECKING | |
2979 | if (TREE_CODE (var) == SSA_NAME) | |
2980 | gcc_assert (is_old_name (var)); | |
2981 | else | |
2982 | gcc_assert (symbol_marked_for_renaming (var)); | |
2983 | #endif | |
2984 | ||
2985 | /* Get all the definition sites for VAR. */ | |
2986 | db = find_def_blocks_for (var); | |
2987 | ||
2988 | /* No need to do anything if there were no definitions to VAR. */ | |
2989 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
2990 | return; | |
2991 | ||
2992 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 2993 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
2994 | pruned_idf = BITMAP_ALLOC (NULL); |
2995 | ||
2996 | if (TREE_CODE (var) == SSA_NAME) | |
2997 | { | |
2998 | if (update_flags == TODO_update_ssa) | |
2999 | { | |
3000 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3001 | only interested in IDF blocks dominated by the nearest | |
3002 | common dominator of all the definition blocks. */ | |
3003 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3004 | db->def_blocks); | |
0bca51f0 DN |
3005 | if (entry != ENTRY_BLOCK_PTR) |
3006 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) | |
3007 | if (BASIC_BLOCK (i) != entry | |
3008 | && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) | |
3009 | bitmap_set_bit (pruned_idf, i); | |
3010 | } | |
3011 | else | |
3012 | { | |
3013 | /* Otherwise, do not prune the IDF for VAR. */ | |
3014 | gcc_assert (update_flags == TODO_update_ssa_full_phi); | |
3015 | bitmap_copy (pruned_idf, idf); | |
3016 | } | |
3017 | } | |
3018 | else | |
3019 | { | |
3020 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3021 | for the first time, so we need to compute the full IDF for | |
3022 | it. */ | |
3023 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
3024 | } |
3025 | ||
3026 | if (!bitmap_empty_p (pruned_idf)) | |
3027 | { | |
3028 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3029 | are included in the region to be updated. The feeding blocks | |
3030 | are important to guarantee that the PHI arguments are renamed | |
3031 | properly. */ | |
38635499 DN |
3032 | |
3033 | /* FIXME, this is not needed if we are updating symbols. We are | |
3034 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
3035 | bitmap_ior_into (blocks, pruned_idf); |
3036 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3037 | { | |
3038 | edge e; | |
3039 | edge_iterator ei; | |
3040 | basic_block bb = BASIC_BLOCK (i); | |
3041 | ||
3042 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3043 | if (e->src->index >= 0) | |
3044 | bitmap_set_bit (blocks, e->src->index); | |
3045 | } | |
3046 | ||
3047 | insert_phi_nodes_for (var, pruned_idf, true); | |
3048 | } | |
3049 | ||
3050 | BITMAP_FREE (pruned_idf); | |
3051 | BITMAP_FREE (idf); | |
3052 | } | |
3053 | ||
3054 | ||
84d65814 DN |
3055 | /* Heuristic to determine whether SSA name mappings for virtual names |
3056 | should be discarded and their symbols rewritten from scratch. When | |
3057 | there is a large number of mappings for virtual names, the | |
3058 | insertion of PHI nodes for the old names in the mappings takes | |
3059 | considerable more time than if we inserted PHI nodes for the | |
3060 | symbols instead. | |
3061 | ||
3062 | Currently the heuristic takes these stats into account: | |
3063 | ||
3064 | - Number of mappings for virtual SSA names. | |
3065 | - Number of distinct virtual symbols involved in those mappings. | |
3066 | ||
3067 | If the number of virtual mappings is much larger than the number of | |
3068 | virtual symbols, then it will be faster to compute PHI insertion | |
3069 | spots for the symbols. Even if this involves traversing the whole | |
3070 | CFG, which is what happens when symbols are renamed from scratch. */ | |
3071 | ||
3072 | static bool | |
3073 | switch_virtuals_to_full_rewrite_p (void) | |
3074 | { | |
3075 | if (update_ssa_stats.num_virtual_mappings < (unsigned) MIN_VIRTUAL_MAPPINGS) | |
3076 | return false; | |
3077 | ||
3078 | if (update_ssa_stats.num_virtual_mappings | |
3079 | > (unsigned) VIRTUAL_MAPPINGS_TO_SYMS_RATIO | |
3080 | * update_ssa_stats.num_virtual_symbols) | |
3081 | return true; | |
3082 | ||
3083 | return false; | |
3084 | } | |
3085 | ||
3086 | ||
3087 | /* Remove every virtual mapping and mark all the affected virtual | |
3088 | symbols for renaming. */ | |
3089 | ||
3090 | static void | |
3091 | switch_virtuals_to_full_rewrite (void) | |
3092 | { | |
dfea6c85 | 3093 | unsigned i = 0; |
b6e7e9af | 3094 | sbitmap_iterator sbi; |
84d65814 DN |
3095 | |
3096 | if (dump_file) | |
3097 | { | |
3098 | fprintf (dump_file, "\nEnabled virtual name mapping heuristic.\n"); | |
3099 | fprintf (dump_file, "\tNumber of virtual mappings: %7u\n", | |
3100 | update_ssa_stats.num_virtual_mappings); | |
3101 | fprintf (dump_file, "\tNumber of unique virtual symbols: %7u\n", | |
3102 | update_ssa_stats.num_virtual_symbols); | |
3103 | fprintf (dump_file, "Updating FUD-chains from top of CFG will be " | |
3104 | "faster than processing\nthe name mappings.\n\n"); | |
3105 | } | |
3106 | ||
3107 | /* Remove all virtual names from NEW_SSA_NAMES and OLD_SSA_NAMES. | |
3108 | Note that it is not really necessary to remove the mappings from | |
3109 | REPL_TBL, that would only waste time. */ | |
b6e7e9af | 3110 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
84d65814 | 3111 | if (!is_gimple_reg (ssa_name (i))) |
b6e7e9af | 3112 | RESET_BIT (new_ssa_names, i); |
84d65814 | 3113 | |
b6e7e9af | 3114 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
84d65814 | 3115 | if (!is_gimple_reg (ssa_name (i))) |
b6e7e9af | 3116 | RESET_BIT (old_ssa_names, i); |
84d65814 | 3117 | |
38635499 | 3118 | mark_set_for_renaming (update_ssa_stats.virtual_symbols); |
84d65814 DN |
3119 | } |
3120 | ||
3121 | ||
0bca51f0 DN |
3122 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of |
3123 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3124 | ||
3125 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3126 | NEW_SSA_NAMES are all re-written to be reached by the | |
3127 | appropriate definition from NEW_SSA_NAMES. | |
3128 | ||
3129 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3130 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3131 | ||
3132 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
3133 | calling register_new_name_mapping for every pair of names that the | |
3134 | caller wants to replace. | |
3135 | ||
3136 | The caller identifies the new names that have been inserted and the | |
3137 | names that need to be replaced by calling register_new_name_mapping | |
3138 | for every pair <NEW, OLD>. Note that the function assumes that the | |
3139 | new names have already been inserted in the IL. | |
3140 | ||
3141 | For instance, given the following code: | |
3142 | ||
3143 | 1 L0: | |
3144 | 2 x_1 = PHI (0, x_5) | |
3145 | 3 if (x_1 < 10) | |
3146 | 4 if (x_1 > 7) | |
3147 | 5 y_2 = 0 | |
3148 | 6 else | |
3149 | 7 y_3 = x_1 + x_7 | |
3150 | 8 endif | |
3151 | 9 x_5 = x_1 + 1 | |
3152 | 10 goto L0; | |
3153 | 11 endif | |
3154 | ||
3155 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3156 | ||
3157 | 1 L0: | |
3158 | 2 x_1 = PHI (0, x_5) | |
3159 | 3 if (x_1 < 10) | |
3160 | 4 x_10 = ... | |
3161 | 5 if (x_1 > 7) | |
3162 | 6 y_2 = 0 | |
3163 | 7 else | |
3164 | 8 x_11 = ... | |
3165 | 9 y_3 = x_1 + x_7 | |
3166 | 10 endif | |
3167 | 11 x_5 = x_1 + 1 | |
3168 | 12 goto L0; | |
3169 | 13 endif | |
3170 | ||
3171 | We want to replace all the uses of x_1 with the new definitions of | |
3172 | x_10 and x_11. Note that the only uses that should be replaced are | |
3173 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3174 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3175 | renaming). | |
3176 | ||
3177 | Additionally, we may need to insert a PHI node at line 11 because | |
3178 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3179 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3180 | nodes is optional. They are not strictly necessary to preserve the | |
3181 | SSA form, and depending on what the caller inserted, they may not | |
3182 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3183 | aspects of how update_ssa operates, see the documentation for | |
3184 | TODO_update_ssa*. */ | |
3185 | ||
3186 | void | |
3187 | update_ssa (unsigned update_flags) | |
3188 | { | |
0bca51f0 DN |
3189 | basic_block bb, start_bb; |
3190 | bitmap_iterator bi; | |
dfea6c85 | 3191 | unsigned i = 0; |
0bca51f0 | 3192 | bool insert_phi_p; |
b6e7e9af | 3193 | sbitmap_iterator sbi; |
0bca51f0 | 3194 | |
5006671f | 3195 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
3196 | return; |
3197 | ||
3198 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
3199 | ||
5006671f RG |
3200 | if (!update_ssa_initialized_fn) |
3201 | init_update_ssa (cfun); | |
3202 | gcc_assert (update_ssa_initialized_fn == cfun); | |
3203 | ||
2ce79879 ZD |
3204 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
3205 | if (!phis_to_rewrite) | |
726a989a | 3206 | phis_to_rewrite = VEC_alloc (gimple_vec, heap, last_basic_block); |
95dd3097 | 3207 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3208 | |
0bca51f0 DN |
3209 | /* Ensure that the dominance information is up-to-date. */ |
3210 | calculate_dominance_info (CDI_DOMINATORS); | |
3211 | ||
3212 | /* Only one update flag should be set. */ | |
3213 | gcc_assert (update_flags == TODO_update_ssa | |
3214 | || update_flags == TODO_update_ssa_no_phi | |
3215 | || update_flags == TODO_update_ssa_full_phi | |
3216 | || update_flags == TODO_update_ssa_only_virtuals); | |
3217 | ||
3218 | /* If we only need to update virtuals, remove all the mappings for | |
84d65814 DN |
3219 | real names before proceeding. The caller is responsible for |
3220 | having dealt with the name mappings before calling update_ssa. */ | |
0bca51f0 DN |
3221 | if (update_flags == TODO_update_ssa_only_virtuals) |
3222 | { | |
3223 | sbitmap_zero (old_ssa_names); | |
3224 | sbitmap_zero (new_ssa_names); | |
3225 | htab_empty (repl_tbl); | |
0bca51f0 DN |
3226 | } |
3227 | ||
84d65814 | 3228 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 DN |
3229 | |
3230 | if (insert_phi_p) | |
3231 | { | |
9caf90a8 KH |
3232 | /* If the caller requested PHI nodes to be added, initialize |
3233 | live-in information data structures (DEF_BLOCKS). */ | |
0bca51f0 DN |
3234 | |
3235 | /* For each SSA name N, the DEF_BLOCKS table describes where the | |
3236 | name is defined, which blocks have PHI nodes for N, and which | |
3237 | blocks have uses of N (i.e., N is live-on-entry in those | |
3238 | blocks). */ | |
3239 | def_blocks = htab_create (num_ssa_names, def_blocks_hash, | |
3240 | def_blocks_eq, def_blocks_free); | |
3241 | } | |
3242 | else | |
3243 | { | |
0bca51f0 DN |
3244 | def_blocks = NULL; |
3245 | } | |
3246 | ||
84d65814 DN |
3247 | /* Heuristic to avoid massive slow downs when the replacement |
3248 | mappings include lots of virtual names. */ | |
3249 | if (insert_phi_p && switch_virtuals_to_full_rewrite_p ()) | |
3250 | switch_virtuals_to_full_rewrite (); | |
3251 | ||
3252 | /* If there are names defined in the replacement table, prepare | |
3253 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3254 | OLD_SSA_NAMES. */ | |
3255 | if (sbitmap_first_set_bit (new_ssa_names) >= 0) | |
3256 | { | |
95dd3097 | 3257 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3258 | |
3259 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3260 | removal, and there are no symbols to rename, then there's | |
3261 | nothing else to do. */ | |
3262 | if (sbitmap_first_set_bit (new_ssa_names) < 0 | |
5006671f | 3263 | && bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
84d65814 DN |
3264 | goto done; |
3265 | } | |
3266 | ||
3267 | /* Next, determine the block at which to start the renaming process. */ | |
5006671f | 3268 | if (!bitmap_empty_p (SYMS_TO_RENAME (cfun))) |
84d65814 DN |
3269 | { |
3270 | /* If we have to rename some symbols from scratch, we need to | |
3271 | start the process at the root of the CFG. FIXME, it should | |
3272 | be possible to determine the nearest block that had a | |
3273 | definition for each of the symbols that are marked for | |
3274 | updating. For now this seems more work than it's worth. */ | |
3275 | start_bb = ENTRY_BLOCK_PTR; | |
3276 | ||
38635499 DN |
3277 | /* Traverse the CFG looking for existing definitions and uses of |
3278 | symbols in SYMS_TO_RENAME. Mark interesting blocks and | |
3279 | statements and set local live-in information for the PHI | |
3280 | placement heuristics. */ | |
95dd3097 | 3281 | prepare_block_for_update (start_bb, insert_phi_p); |
0bca51f0 DN |
3282 | } |
3283 | else | |
84d65814 DN |
3284 | { |
3285 | /* Otherwise, the entry block to the region is the nearest | |
3286 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3287 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3288 | blocks_to_update); | |
84d65814 | 3289 | } |
0bca51f0 DN |
3290 | |
3291 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3292 | of every block, creating new definitions for names in OLD_SSA_NAMES |
0bca51f0 DN |
3293 | and for symbols in SYMS_TO_RENAME. */ |
3294 | if (insert_phi_p) | |
3295 | { | |
9caf90a8 KH |
3296 | bitmap *dfs; |
3297 | ||
3298 | /* If the caller requested PHI nodes to be added, compute | |
3299 | dominance frontiers. */ | |
858904db | 3300 | dfs = XNEWVEC (bitmap, last_basic_block); |
9caf90a8 KH |
3301 | FOR_EACH_BB (bb) |
3302 | dfs[bb->index] = BITMAP_ALLOC (NULL); | |
3303 | compute_dominance_frontiers (dfs); | |
3304 | ||
0bca51f0 DN |
3305 | if (sbitmap_first_set_bit (old_ssa_names) >= 0) |
3306 | { | |
b6e7e9af KH |
3307 | sbitmap_iterator sbi; |
3308 | ||
84d65814 DN |
3309 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3310 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3311 | will grow while we are traversing it (but it will not | |
3312 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3313 | for traversal. */ | |
0bca51f0 DN |
3314 | sbitmap tmp = sbitmap_alloc (old_ssa_names->n_bits); |
3315 | sbitmap_copy (tmp, old_ssa_names); | |
b6e7e9af | 3316 | EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i, sbi) |
95dd3097 | 3317 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3318 | update_flags); |
0bca51f0 DN |
3319 | sbitmap_free (tmp); |
3320 | } | |
3321 | ||
5006671f | 3322 | EXECUTE_IF_SET_IN_BITMAP (SYMS_TO_RENAME (cfun), 0, i, bi) |
38635499 DN |
3323 | insert_updated_phi_nodes_for (referenced_var (i), dfs, blocks_to_update, |
3324 | update_flags); | |
0bca51f0 | 3325 | |
9caf90a8 KH |
3326 | FOR_EACH_BB (bb) |
3327 | BITMAP_FREE (dfs[bb->index]); | |
3328 | free (dfs); | |
3329 | ||
0bca51f0 DN |
3330 | /* Insertion of PHI nodes may have added blocks to the region. |
3331 | We need to re-compute START_BB to include the newly added | |
3332 | blocks. */ | |
3333 | if (start_bb != ENTRY_BLOCK_PTR) | |
95dd3097 ZD |
3334 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3335 | blocks_to_update); | |
0bca51f0 DN |
3336 | } |
3337 | ||
3338 | /* Reset the current definition for name and symbol before renaming | |
3339 | the sub-graph. */ | |
b6e7e9af KH |
3340 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
3341 | set_current_def (ssa_name (i), NULL_TREE); | |
0bca51f0 | 3342 | |
5006671f | 3343 | EXECUTE_IF_SET_IN_BITMAP (SYMS_TO_RENAME (cfun), 0, i, bi) |
0bca51f0 DN |
3344 | set_current_def (referenced_var (i), NULL_TREE); |
3345 | ||
3346 | /* Now start the renaming process at START_BB. */ | |
ccf5c864 PB |
3347 | interesting_blocks = sbitmap_alloc (last_basic_block); |
3348 | sbitmap_zero (interesting_blocks); | |
95dd3097 | 3349 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
ccf5c864 | 3350 | SET_BIT (interesting_blocks, i); |
0bca51f0 | 3351 | |
ccf5c864 | 3352 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
0bca51f0 | 3353 | |
ccf5c864 | 3354 | sbitmap_free (interesting_blocks); |
0bca51f0 DN |
3355 | |
3356 | /* Debugging dumps. */ | |
3357 | if (dump_file) | |
3358 | { | |
3359 | int c; | |
3360 | unsigned i; | |
3361 | ||
84d65814 | 3362 | dump_update_ssa (dump_file); |
0bca51f0 DN |
3363 | |
3364 | fprintf (dump_file, "Incremental SSA update started at block: %d\n\n", | |
3365 | start_bb->index); | |
3366 | ||
3367 | c = 0; | |
95dd3097 | 3368 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3369 | c++; |
3370 | fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block); | |
3371 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n\n", | |
3372 | c, PERCENT (c, last_basic_block)); | |
3373 | ||
3374 | if (dump_flags & TDF_DETAILS) | |
3375 | { | |
3376 | fprintf (dump_file, "Affected blocks: "); | |
95dd3097 | 3377 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3378 | fprintf (dump_file, "%u ", i); |
3379 | fprintf (dump_file, "\n"); | |
3380 | } | |
3381 | ||
3382 | fprintf (dump_file, "\n\n"); | |
3383 | } | |
3384 | ||
3385 | /* Free allocated memory. */ | |
84d65814 | 3386 | done: |
0bca51f0 DN |
3387 | delete_update_ssa (); |
3388 | ||
3389 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3390 | } |