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Commit | Line | Data |
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6de9cd9a | 1 | /* Rewrite a program in Normal form into SSA. |
fa10beec | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008 |
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 | ||
726a989a | 115 | |
0bca51f0 DN |
116 | /* Symbols whose SSA form needs to be updated or created for the first |
117 | time. */ | |
118 | static bitmap syms_to_rename; | |
119 | ||
38635499 DN |
120 | /* Subset of SYMS_TO_RENAME. Contains all the GIMPLE register symbols |
121 | that have been marked for renaming. */ | |
122 | static bitmap regs_to_rename; | |
123 | ||
124 | /* Subset of SYMS_TO_RENAME. Contains all the memory symbols | |
125 | that have been marked for renaming. */ | |
126 | static bitmap mem_syms_to_rename; | |
127 | ||
0bca51f0 DN |
128 | /* Set of SSA names that have been marked to be released after they |
129 | were registered in the replacement table. They will be finally | |
130 | released after we finish updating the SSA web. */ | |
131 | static bitmap names_to_release; | |
132 | ||
726a989a | 133 | static VEC(gimple_vec, heap) *phis_to_rewrite; |
2ce79879 ZD |
134 | |
135 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
136 | static bitmap blocks_with_phis_to_rewrite; |
137 | ||
0bca51f0 DN |
138 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
139 | to grow as the callers to register_new_name_mapping will typically | |
140 | create new names on the fly. FIXME. Currently set to 1/3 to avoid | |
141 | frequent reallocations but still need to find a reasonable growth | |
142 | strategy. */ | |
143 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) | |
144 | ||
145 | /* Tuple used to represent replacement mappings. */ | |
146 | struct repl_map_d | |
147 | { | |
148 | tree name; | |
149 | bitmap set; | |
150 | }; | |
151 | ||
726a989a | 152 | |
0bca51f0 DN |
153 | /* NEW -> OLD_SET replacement table. If we are replacing several |
154 | existing SSA names O_1, O_2, ..., O_j with a new name N_i, | |
155 | then REPL_TBL[N_i] = { O_1, O_2, ..., O_j }. */ | |
156 | static htab_t repl_tbl; | |
157 | ||
158 | /* true if register_new_name_mapping needs to initialize the data | |
159 | structures needed by update_ssa. */ | |
160 | static bool need_to_initialize_update_ssa_p = true; | |
161 | ||
162 | /* true if update_ssa needs to update virtual operands. */ | |
163 | static bool need_to_update_vops_p = false; | |
164 | ||
84d65814 DN |
165 | /* Statistics kept by update_ssa to use in the virtual mapping |
166 | heuristic. If the number of virtual mappings is beyond certain | |
167 | threshold, the updater will switch from using the mappings into | |
168 | renaming the virtual symbols from scratch. In some cases, the | |
169 | large number of name mappings for virtual names causes significant | |
170 | slowdowns in the PHI insertion code. */ | |
171 | struct update_ssa_stats_d | |
172 | { | |
173 | unsigned num_virtual_mappings; | |
174 | unsigned num_total_mappings; | |
175 | bitmap virtual_symbols; | |
176 | unsigned num_virtual_symbols; | |
177 | }; | |
178 | static struct update_ssa_stats_d update_ssa_stats; | |
0bca51f0 | 179 | |
6de9cd9a DN |
180 | /* Global data to attach to the main dominator walk structure. */ |
181 | struct mark_def_sites_global_data | |
182 | { | |
0bca51f0 DN |
183 | /* This bitmap contains the variables which are set before they |
184 | are used in a basic block. */ | |
7d793e36 | 185 | bitmap kills; |
5f240ec4 ZD |
186 | |
187 | /* Bitmap of names to rename. */ | |
188 | sbitmap names_to_rename; | |
0bca51f0 DN |
189 | |
190 | /* Set of blocks that mark_def_sites deems interesting for the | |
191 | renamer to process. */ | |
192 | sbitmap interesting_blocks; | |
6de9cd9a DN |
193 | }; |
194 | ||
5f240ec4 | 195 | |
0bca51f0 | 196 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
197 | struct ssa_name_info |
198 | { | |
38635499 | 199 | /* The current reaching definition replacing this SSA name. */ |
95dd3097 ZD |
200 | tree current_def; |
201 | ||
5f240ec4 ZD |
202 | /* This field indicates whether or not the variable may need PHI nodes. |
203 | See the enum's definition for more detailed information about the | |
204 | states. */ | |
205 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
206 | ||
95dd3097 | 207 | /* Age of this record (so that info_for_ssa_name table can be cleared |
fa10beec | 208 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields |
95dd3097 ZD |
209 | are assumed to be null. */ |
210 | unsigned age; | |
5f240ec4 | 211 | }; |
6de9cd9a | 212 | |
95dd3097 ZD |
213 | /* The information associated with names. */ |
214 | typedef struct ssa_name_info *ssa_name_info_p; | |
215 | DEF_VEC_P (ssa_name_info_p); | |
216 | DEF_VEC_ALLOC_P (ssa_name_info_p, heap); | |
217 | ||
218 | static VEC(ssa_name_info_p, heap) *info_for_ssa_name; | |
219 | static unsigned current_info_for_ssa_name_age; | |
220 | ||
221 | /* The set of blocks affected by update_ssa. */ | |
95dd3097 | 222 | static bitmap blocks_to_update; |
6de9cd9a | 223 | |
0bca51f0 DN |
224 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
225 | called several times to do different, but related, tasks. | |
226 | Initially, we need it to rename the whole program into SSA form. | |
227 | At other times, we may need it to only rename into SSA newly | |
228 | exposed symbols. Finally, we can also call it to incrementally fix | |
229 | an already built SSA web. */ | |
230 | enum rewrite_mode { | |
231 | /* Convert the whole function into SSA form. */ | |
232 | REWRITE_ALL, | |
233 | ||
234 | /* Incrementally update the SSA web by replacing existing SSA | |
235 | names with new ones. See update_ssa for details. */ | |
236 | REWRITE_UPDATE | |
237 | }; | |
238 | ||
239 | ||
0bca51f0 | 240 | |
7d5f9cc6 | 241 | |
84d65814 DN |
242 | /* Prototypes for debugging functions. */ |
243 | extern void dump_tree_ssa (FILE *); | |
244 | extern void debug_tree_ssa (void); | |
245 | extern void debug_def_blocks (void); | |
246 | extern void dump_tree_ssa_stats (FILE *); | |
247 | extern void debug_tree_ssa_stats (void); | |
38635499 DN |
248 | extern void dump_update_ssa (FILE *); |
249 | extern void debug_update_ssa (void); | |
250 | extern void dump_names_replaced_by (FILE *, tree); | |
251 | extern void debug_names_replaced_by (tree); | |
252 | extern void dump_def_blocks (FILE *); | |
253 | extern void debug_def_blocks (void); | |
254 | extern void dump_defs_stack (FILE *, int); | |
255 | extern void debug_defs_stack (int); | |
256 | extern void dump_currdefs (FILE *); | |
257 | extern void debug_currdefs (void); | |
84d65814 | 258 | |
726a989a RB |
259 | /* Return true if STMT needs to be rewritten. When renaming a subset |
260 | of the variables, not all statements will be processed. This is | |
261 | decided in mark_def_sites. */ | |
262 | ||
263 | static inline bool | |
264 | rewrite_uses_p (gimple stmt) | |
265 | { | |
266 | return gimple_visited_p (stmt); | |
267 | } | |
268 | ||
269 | ||
270 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
271 | ||
272 | static inline void | |
273 | set_rewrite_uses (gimple stmt, bool rewrite_p) | |
274 | { | |
275 | gimple_set_visited (stmt, rewrite_p); | |
276 | } | |
277 | ||
278 | ||
279 | /* Return true if the DEFs created by statement STMT should be | |
280 | registered when marking new definition sites. This is slightly | |
281 | different than rewrite_uses_p: it's used by update_ssa to | |
282 | distinguish statements that need to have both uses and defs | |
283 | processed from those that only need to have their defs processed. | |
284 | Statements that define new SSA names only need to have their defs | |
285 | registered, but they don't need to have their uses renamed. */ | |
286 | ||
287 | static inline bool | |
288 | register_defs_p (gimple stmt) | |
289 | { | |
290 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
291 | } | |
292 | ||
293 | ||
294 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
295 | ||
296 | static inline void | |
297 | set_register_defs (gimple stmt, bool register_defs_p) | |
298 | { | |
299 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
300 | } | |
301 | ||
302 | ||
5f240ec4 ZD |
303 | /* Get the information associated with NAME. */ |
304 | ||
38635499 | 305 | static inline ssa_name_info_p |
5f240ec4 ZD |
306 | get_ssa_name_ann (tree name) |
307 | { | |
95dd3097 ZD |
308 | unsigned ver = SSA_NAME_VERSION (name); |
309 | unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name); | |
310 | struct ssa_name_info *info; | |
311 | ||
312 | if (ver >= len) | |
313 | { | |
314 | unsigned new_len = num_ssa_names; | |
315 | ||
316 | VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name, new_len); | |
317 | while (len++ < new_len) | |
318 | { | |
319 | struct ssa_name_info *info = XCNEW (struct ssa_name_info); | |
320 | info->age = current_info_for_ssa_name_age; | |
321 | VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info); | |
322 | } | |
323 | } | |
324 | ||
325 | info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver); | |
326 | if (info->age < current_info_for_ssa_name_age) | |
327 | { | |
328 | info->need_phi_state = 0; | |
329 | info->current_def = NULL_TREE; | |
330 | info->age = current_info_for_ssa_name_age; | |
331 | } | |
5f240ec4 | 332 | |
95dd3097 | 333 | return info; |
5f240ec4 ZD |
334 | } |
335 | ||
38635499 DN |
336 | |
337 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
338 | |
339 | static void | |
340 | clear_ssa_name_info (void) | |
341 | { | |
342 | current_info_for_ssa_name_age++; | |
343 | } | |
7256233c | 344 | |
38635499 DN |
345 | |
346 | /* Get phi_state field for VAR. */ | |
5f240ec4 ZD |
347 | |
348 | static inline enum need_phi_state | |
349 | get_phi_state (tree var) | |
350 | { | |
351 | if (TREE_CODE (var) == SSA_NAME) | |
352 | return get_ssa_name_ann (var)->need_phi_state; | |
353 | else | |
354 | return var_ann (var)->need_phi_state; | |
355 | } | |
356 | ||
7256233c | 357 | |
5f240ec4 ZD |
358 | /* Sets phi_state field for VAR to STATE. */ |
359 | ||
360 | static inline void | |
361 | set_phi_state (tree var, enum need_phi_state state) | |
362 | { | |
363 | if (TREE_CODE (var) == SSA_NAME) | |
364 | get_ssa_name_ann (var)->need_phi_state = state; | |
365 | else | |
366 | var_ann (var)->need_phi_state = state; | |
367 | } | |
368 | ||
7256233c | 369 | |
5f240ec4 ZD |
370 | /* Return the current definition for VAR. */ |
371 | ||
84d65814 | 372 | tree |
5f240ec4 ZD |
373 | get_current_def (tree var) |
374 | { | |
375 | if (TREE_CODE (var) == SSA_NAME) | |
376 | return get_ssa_name_ann (var)->current_def; | |
377 | else | |
378 | return var_ann (var)->current_def; | |
379 | } | |
380 | ||
7256233c | 381 | |
5f240ec4 ZD |
382 | /* Sets current definition of VAR to DEF. */ |
383 | ||
84d65814 | 384 | void |
5f240ec4 ZD |
385 | set_current_def (tree var, tree def) |
386 | { | |
387 | if (TREE_CODE (var) == SSA_NAME) | |
388 | get_ssa_name_ann (var)->current_def = def; | |
389 | else | |
390 | var_ann (var)->current_def = def; | |
391 | } | |
392 | ||
7256233c | 393 | |
fa10beec | 394 | /* Compute global livein information given the set of blocks where |
6de9cd9a DN |
395 | an object is locally live at the start of the block (LIVEIN) |
396 | and the set of blocks where the object is defined (DEF_BLOCKS). | |
397 | ||
398 | Note: This routine augments the existing local livein information | |
399 | to include global livein (i.e., it modifies the underlying bitmap | |
400 | for LIVEIN). */ | |
401 | ||
5f240ec4 | 402 | void |
726a989a | 403 | compute_global_livein (bitmap livein ATTRIBUTE_UNUSED, bitmap def_blocks ATTRIBUTE_UNUSED) |
6de9cd9a DN |
404 | { |
405 | basic_block bb, *worklist, *tos; | |
3cd8c58a | 406 | unsigned i; |
87c476a2 | 407 | bitmap_iterator bi; |
6de9cd9a DN |
408 | |
409 | tos = worklist | |
0bca51f0 | 410 | = (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1)); |
6de9cd9a | 411 | |
87c476a2 | 412 | EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi) |
38635499 | 413 | *tos++ = BASIC_BLOCK (i); |
6de9cd9a DN |
414 | |
415 | /* Iterate until the worklist is empty. */ | |
416 | while (tos != worklist) | |
417 | { | |
418 | edge e; | |
628f6a4e | 419 | edge_iterator ei; |
6de9cd9a DN |
420 | |
421 | /* Pull a block off the worklist. */ | |
422 | bb = *--tos; | |
423 | ||
424 | /* For each predecessor block. */ | |
628f6a4e | 425 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
426 | { |
427 | basic_block pred = e->src; | |
428 | int pred_index = pred->index; | |
429 | ||
430 | /* None of this is necessary for the entry block. */ | |
431 | if (pred != ENTRY_BLOCK_PTR | |
432 | && ! bitmap_bit_p (livein, pred_index) | |
433 | && ! bitmap_bit_p (def_blocks, pred_index)) | |
434 | { | |
435 | *tos++ = pred; | |
436 | bitmap_set_bit (livein, pred_index); | |
437 | } | |
438 | } | |
439 | } | |
440 | ||
441 | free (worklist); | |
442 | } | |
443 | ||
444 | ||
95dd3097 ZD |
445 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
446 | all statements in basic block BB. */ | |
447 | ||
448 | static void | |
449 | initialize_flags_in_bb (basic_block bb) | |
450 | { | |
726a989a RB |
451 | gimple stmt; |
452 | gimple_stmt_iterator gsi; | |
95dd3097 | 453 | |
726a989a | 454 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 455 | { |
726a989a RB |
456 | gimple phi = gsi_stmt (gsi); |
457 | set_rewrite_uses (phi, false); | |
458 | set_register_defs (phi, false); | |
95dd3097 ZD |
459 | } |
460 | ||
726a989a | 461 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 462 | { |
726a989a RB |
463 | stmt = gsi_stmt (gsi); |
464 | ||
95dd3097 ZD |
465 | /* We are going to use the operand cache API, such as |
466 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
467 | cache for each statement should be up-to-date. */ | |
726a989a RB |
468 | gcc_assert (!gimple_modified_p (stmt)); |
469 | set_rewrite_uses (stmt, false); | |
470 | set_register_defs (stmt, false); | |
95dd3097 ZD |
471 | } |
472 | } | |
473 | ||
474 | /* Mark block BB as interesting for update_ssa. */ | |
475 | ||
476 | static void | |
477 | mark_block_for_update (basic_block bb) | |
478 | { | |
479 | gcc_assert (blocks_to_update != NULL); | |
480 | if (bitmap_bit_p (blocks_to_update, bb->index)) | |
481 | return; | |
482 | bitmap_set_bit (blocks_to_update, bb->index); | |
483 | initialize_flags_in_bb (bb); | |
484 | } | |
485 | ||
7256233c DN |
486 | /* Return the set of blocks where variable VAR is defined and the blocks |
487 | where VAR is live on entry (livein). If no entry is found in | |
488 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 489 | |
7256233c DN |
490 | static inline struct def_blocks_d * |
491 | get_def_blocks_for (tree var) | |
6de9cd9a | 492 | { |
7256233c DN |
493 | struct def_blocks_d db, *db_p; |
494 | void **slot; | |
6de9cd9a | 495 | |
7256233c DN |
496 | db.var = var; |
497 | slot = htab_find_slot (def_blocks, (void *) &db, INSERT); | |
498 | if (*slot == NULL) | |
6de9cd9a | 499 | { |
858904db | 500 | db_p = XNEW (struct def_blocks_d); |
7256233c DN |
501 | db_p->var = var; |
502 | db_p->def_blocks = BITMAP_ALLOC (NULL); | |
503 | db_p->phi_blocks = BITMAP_ALLOC (NULL); | |
504 | db_p->livein_blocks = BITMAP_ALLOC (NULL); | |
505 | *slot = (void *) db_p; | |
a32b97a2 | 506 | } |
7256233c DN |
507 | else |
508 | db_p = (struct def_blocks_d *) *slot; | |
a32b97a2 | 509 | |
7256233c | 510 | return db_p; |
6de9cd9a DN |
511 | } |
512 | ||
7d5f9cc6 | 513 | |
5f240ec4 | 514 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 515 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
516 | |
517 | static void | |
0bca51f0 | 518 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a DN |
519 | { |
520 | struct def_blocks_d *db_p; | |
34eb8991 JL |
521 | enum need_phi_state state; |
522 | ||
5f240ec4 | 523 | state = get_phi_state (var); |
6de9cd9a DN |
524 | db_p = get_def_blocks_for (var); |
525 | ||
526 | /* Set the bit corresponding to the block where VAR is defined. */ | |
527 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
528 | if (phi_p) |
529 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 530 | |
7256233c | 531 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
532 | |
533 | If we are in the UNKNOWN state, then this is the first definition | |
534 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 535 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
536 | transition to NEED_PHI_STATE_NO). |
537 | ||
538 | If we are in any other state, then we either have multiple definitions | |
539 | of this variable occurring in different blocks or we saw a use of the | |
540 | variable which was not dominated by the block containing the | |
541 | definition(s). In this case we may need a PHI node, so enter | |
542 | state NEED_PHI_STATE_MAYBE. */ | |
543 | if (state == NEED_PHI_STATE_UNKNOWN) | |
5f240ec4 | 544 | set_phi_state (var, NEED_PHI_STATE_NO); |
6de9cd9a | 545 | else |
5f240ec4 | 546 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
547 | } |
548 | ||
549 | ||
550 | /* Mark block BB as having VAR live at the entry to BB. */ | |
551 | ||
552 | static void | |
553 | set_livein_block (tree var, basic_block bb) | |
554 | { | |
555 | struct def_blocks_d *db_p; | |
5f240ec4 | 556 | enum need_phi_state state = get_phi_state (var); |
6de9cd9a DN |
557 | |
558 | db_p = get_def_blocks_for (var); | |
559 | ||
560 | /* Set the bit corresponding to the block where VAR is live in. */ | |
561 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
562 | ||
7256233c | 563 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
564 | |
565 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
566 | by the single block containing the definition(s) of this variable. If | |
567 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
568 | NEED_PHI_STATE_MAYBE. */ | |
569 | if (state == NEED_PHI_STATE_NO) | |
570 | { | |
571 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
572 | ||
573 | if (def_block_index == -1 | |
574 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
575 | BASIC_BLOCK (def_block_index))) | |
5f240ec4 | 576 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
577 | } |
578 | else | |
5f240ec4 | 579 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
580 | } |
581 | ||
582 | ||
0bca51f0 | 583 | /* Return true if symbol SYM is marked for renaming. */ |
6de9cd9a | 584 | |
0bca51f0 DN |
585 | static inline bool |
586 | symbol_marked_for_renaming (tree sym) | |
6de9cd9a | 587 | { |
a3648cfc | 588 | return bitmap_bit_p (syms_to_rename, DECL_UID (sym)); |
0bca51f0 DN |
589 | } |
590 | ||
591 | ||
592 | /* Return true if NAME is in OLD_SSA_NAMES. */ | |
6de9cd9a | 593 | |
0bca51f0 DN |
594 | static inline bool |
595 | is_old_name (tree name) | |
596 | { | |
84d65814 DN |
597 | unsigned ver = SSA_NAME_VERSION (name); |
598 | return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver); | |
0bca51f0 DN |
599 | } |
600 | ||
601 | ||
602 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 603 | |
0bca51f0 DN |
604 | static inline bool |
605 | is_new_name (tree name) | |
606 | { | |
84d65814 DN |
607 | unsigned ver = SSA_NAME_VERSION (name); |
608 | return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver); | |
6de9cd9a DN |
609 | } |
610 | ||
7256233c | 611 | |
0bca51f0 | 612 | /* Hashing and equality functions for REPL_TBL. */ |
d00ad49b | 613 | |
0bca51f0 DN |
614 | static hashval_t |
615 | repl_map_hash (const void *p) | |
d00ad49b | 616 | { |
0bca51f0 DN |
617 | return htab_hash_pointer ((const void *)((const struct repl_map_d *)p)->name); |
618 | } | |
d00ad49b | 619 | |
0bca51f0 DN |
620 | static int |
621 | repl_map_eq (const void *p1, const void *p2) | |
622 | { | |
623 | return ((const struct repl_map_d *)p1)->name | |
624 | == ((const struct repl_map_d *)p2)->name; | |
625 | } | |
626 | ||
627 | static void | |
628 | repl_map_free (void *p) | |
629 | { | |
630 | BITMAP_FREE (((struct repl_map_d *)p)->set); | |
631 | free (p); | |
632 | } | |
633 | ||
634 | ||
82d6e6fc | 635 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
636 | |
637 | static inline bitmap | |
82d6e6fc | 638 | names_replaced_by (tree new_tree) |
0bca51f0 DN |
639 | { |
640 | struct repl_map_d m; | |
641 | void **slot; | |
642 | ||
82d6e6fc | 643 | m.name = new_tree; |
0bca51f0 DN |
644 | slot = htab_find_slot (repl_tbl, (void *) &m, NO_INSERT); |
645 | ||
646 | /* If N was not registered in the replacement table, return NULL. */ | |
647 | if (slot == NULL || *slot == NULL) | |
648 | return NULL; | |
649 | ||
650 | return ((struct repl_map_d *) *slot)->set; | |
651 | } | |
652 | ||
653 | ||
82d6e6fc | 654 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
655 | |
656 | static inline void | |
82d6e6fc | 657 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 DN |
658 | { |
659 | struct repl_map_d m, *mp; | |
660 | void **slot; | |
661 | ||
82d6e6fc | 662 | m.name = new_tree; |
0bca51f0 DN |
663 | slot = htab_find_slot (repl_tbl, (void *) &m, INSERT); |
664 | if (*slot == NULL) | |
665 | { | |
858904db | 666 | mp = XNEW (struct repl_map_d); |
82d6e6fc | 667 | mp->name = new_tree; |
0bca51f0 DN |
668 | mp->set = BITMAP_ALLOC (NULL); |
669 | *slot = (void *) mp; | |
670 | } | |
671 | else | |
672 | mp = (struct repl_map_d *) *slot; | |
673 | ||
674 | bitmap_set_bit (mp->set, SSA_NAME_VERSION (old)); | |
675 | } | |
676 | ||
677 | ||
82d6e6fc | 678 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
679 | represents the set of names O_1 ... O_j replaced by N_i. This is |
680 | used by update_ssa and its helpers to introduce new SSA names in an | |
681 | already formed SSA web. */ | |
682 | ||
683 | static void | |
82d6e6fc | 684 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 DN |
685 | { |
686 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
687 | ||
82d6e6fc KG |
688 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
689 | gcc_assert (new_tree != old && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 690 | |
84d65814 | 691 | /* If this mapping is for virtual names, we will need to update |
38635499 DN |
692 | virtual operands. If this is a mapping for .MEM, then we gather |
693 | the symbols associated with each name. */ | |
82d6e6fc | 694 | if (!is_gimple_reg (new_tree)) |
0bca51f0 DN |
695 | { |
696 | tree sym; | |
697 | ||
84d65814 | 698 | need_to_update_vops_p = true; |
0bca51f0 | 699 | |
38635499 DN |
700 | update_ssa_stats.num_virtual_mappings++; |
701 | update_ssa_stats.num_virtual_symbols++; | |
702 | ||
84d65814 DN |
703 | /* Keep counts of virtual mappings and symbols to use in the |
704 | virtual mapping heuristic. If we have large numbers of | |
705 | virtual mappings for a relatively low number of symbols, it | |
706 | will make more sense to rename the symbols from scratch. | |
707 | Otherwise, the insertion of PHI nodes for each of the old | |
708 | names in these mappings will be very slow. */ | |
82d6e6fc | 709 | sym = SSA_NAME_VAR (new_tree); |
38635499 DN |
710 | bitmap_set_bit (update_ssa_stats.virtual_symbols, DECL_UID (sym)); |
711 | } | |
712 | ||
713 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our | |
714 | caller may have created new names since the set was created. */ | |
715 | if (new_ssa_names->n_bits <= num_ssa_names - 1) | |
716 | { | |
717 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
718 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
719 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
720 | } |
721 | ||
0bca51f0 | 722 | /* Update the REPL_TBL table. */ |
82d6e6fc | 723 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 724 | |
0bca51f0 | 725 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 726 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 727 | if (is_new_name (old)) |
82d6e6fc | 728 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 729 | |
82d6e6fc | 730 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 731 | respectively. */ |
82d6e6fc | 732 | SET_BIT (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
0bca51f0 DN |
733 | SET_BIT (old_ssa_names, SSA_NAME_VERSION (old)); |
734 | ||
84d65814 DN |
735 | /* Update mapping counter to use in the virtual mapping heuristic. */ |
736 | update_ssa_stats.num_total_mappings++; | |
0bca51f0 DN |
737 | |
738 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
d00ad49b | 739 | } |
6de9cd9a | 740 | |
6de9cd9a | 741 | |
7256233c DN |
742 | /* Call back for walk_dominator_tree used to collect definition sites |
743 | for every variable in the function. For every statement S in block | |
744 | BB: | |
6de9cd9a | 745 | |
f47c96aa | 746 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
7256233c | 747 | WALK_DATA->GLOBAL_DATA->KILLS. |
6de9cd9a | 748 | |
7256233c | 749 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 750 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 751 | |
7256233c DN |
752 | This information is used to determine which variables are live |
753 | across block boundaries to reduce the number of PHI nodes | |
754 | we create. */ | |
6de9cd9a | 755 | |
7256233c | 756 | static void |
38635499 | 757 | mark_def_sites (struct dom_walk_data *walk_data, basic_block bb, |
726a989a | 758 | gimple_stmt_iterator gsi) |
7256233c | 759 | { |
38635499 DN |
760 | struct mark_def_sites_global_data *gd; |
761 | bitmap kills; | |
726a989a RB |
762 | tree def; |
763 | gimple stmt; | |
7256233c | 764 | use_operand_p use_p; |
7256233c DN |
765 | ssa_op_iter iter; |
766 | ||
726a989a RB |
767 | /* Since this is the first time that we rewrite the program into SSA |
768 | form, force an operand scan on every statement. */ | |
769 | stmt = gsi_stmt (gsi); | |
770 | update_stmt (stmt); | |
7256233c | 771 | |
38635499 DN |
772 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; |
773 | kills = gd->kills; | |
774 | ||
95dd3097 | 775 | gcc_assert (blocks_to_update == NULL); |
726a989a RB |
776 | set_register_defs (stmt, false); |
777 | set_rewrite_uses (stmt, false); | |
7256233c DN |
778 | |
779 | /* If a variable is used before being set, then the variable is live | |
780 | across a block boundary, so mark it live-on-entry to BB. */ | |
38635499 | 781 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
7256233c | 782 | { |
0bca51f0 DN |
783 | tree sym = USE_FROM_PTR (use_p); |
784 | gcc_assert (DECL_P (sym)); | |
a3648cfc | 785 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 786 | set_livein_block (sym, bb); |
726a989a | 787 | set_rewrite_uses (stmt, true); |
7256233c DN |
788 | } |
789 | ||
38635499 DN |
790 | /* Now process the defs. Mark BB as the definition block and add |
791 | each def to the set of killed symbols. */ | |
792 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF) | |
7256233c | 793 | { |
0bca51f0 DN |
794 | gcc_assert (DECL_P (def)); |
795 | set_def_block (def, bb, false); | |
a3648cfc | 796 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 797 | set_register_defs (stmt, true); |
7256233c | 798 | } |
0bca51f0 DN |
799 | |
800 | /* If we found the statement interesting then also mark the block BB | |
801 | as interesting. */ | |
726a989a | 802 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
0bca51f0 | 803 | SET_BIT (gd->interesting_blocks, bb->index); |
7256233c DN |
804 | } |
805 | ||
f074ff6c ZD |
806 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
807 | in the dfs numbering of the dominance tree. */ | |
808 | ||
809 | struct dom_dfsnum | |
810 | { | |
811 | /* Basic block whose index this entry corresponds to. */ | |
812 | unsigned bb_index; | |
813 | ||
814 | /* The dfs number of this node. */ | |
815 | unsigned dfs_num; | |
816 | }; | |
817 | ||
818 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
819 | for qsort. */ | |
820 | ||
821 | static int | |
822 | cmp_dfsnum (const void *a, const void *b) | |
823 | { | |
3d9a9f94 KG |
824 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
825 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
826 | |
827 | return (int) da->dfs_num - (int) db->dfs_num; | |
828 | } | |
829 | ||
830 | /* Among the intervals starting at the N points specified in DEFS, find | |
831 | the one that contains S, and return its bb_index. */ | |
832 | ||
833 | static unsigned | |
834 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
835 | { | |
836 | unsigned f = 0, t = n, m; | |
837 | ||
838 | while (t > f + 1) | |
839 | { | |
840 | m = (f + t) / 2; | |
841 | if (defs[m].dfs_num <= s) | |
842 | f = m; | |
843 | else | |
844 | t = m; | |
845 | } | |
846 | ||
847 | return defs[f].bb_index; | |
848 | } | |
849 | ||
850 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
851 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
852 | ||
853 | static void | |
854 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
855 | { | |
856 | VEC(int, heap) *worklist; | |
857 | bitmap_iterator bi; | |
858 | unsigned i, b, p, u, top; | |
859 | bitmap live_phis; | |
860 | basic_block def_bb, use_bb; | |
861 | edge e; | |
862 | edge_iterator ei; | |
863 | bitmap to_remove; | |
864 | struct dom_dfsnum *defs; | |
865 | unsigned n_defs, adef; | |
866 | ||
867 | if (bitmap_empty_p (uses)) | |
868 | { | |
869 | bitmap_clear (phis); | |
870 | return; | |
871 | } | |
872 | ||
873 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
874 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
875 | to_remove = BITMAP_ALLOC (NULL); | |
876 | bitmap_and_compl (to_remove, kills, uses); | |
877 | bitmap_and_compl_into (phis, to_remove); | |
878 | if (bitmap_empty_p (phis)) | |
879 | { | |
880 | BITMAP_FREE (to_remove); | |
881 | return; | |
882 | } | |
883 | ||
884 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
885 | liveness information, as that may be linear in the size of CFG, and if | |
886 | there are lot of different variables to rewrite, this may lead to quadratic | |
887 | behavior. | |
888 | ||
889 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
890 | then for each of them find the nearest def that dominates them. If this | |
891 | def is a phi node, we mark it live, and if it was not live before, we | |
892 | add the predecessors of its basic block to the worklist. | |
893 | ||
894 | To quickly locate the nearest def that dominates use, we use dfs numbering | |
895 | of the dominance tree (that is already available in order to speed up | |
896 | queries). For each def, we have the interval given by the dfs number on | |
897 | entry to and on exit from the corresponding subtree in the dominance tree. | |
898 | The nearest dominator for a given use is the smallest of these intervals | |
899 | that contains entry and exit dfs numbers for the basic block with the use. | |
900 | If we store the bounds for all the uses to an array and sort it, we can | |
901 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
902 | bitmap_ior (to_remove, kills, phis); | |
903 | n_defs = bitmap_count_bits (to_remove); | |
904 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
905 | defs[0].bb_index = 1; | |
906 | defs[0].dfs_num = 0; | |
907 | adef = 1; | |
908 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
909 | { | |
910 | def_bb = BASIC_BLOCK (i); | |
911 | defs[adef].bb_index = i; | |
912 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
913 | defs[adef + 1].bb_index = i; | |
914 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
915 | adef += 2; | |
916 | } | |
917 | BITMAP_FREE (to_remove); | |
918 | gcc_assert (adef == 2 * n_defs + 1); | |
919 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
920 | gcc_assert (defs[0].bb_index == 1); | |
921 | ||
922 | /* Now each DEFS entry contains the number of the basic block to that the | |
923 | dfs number corresponds. Change them to the number of basic block that | |
924 | corresponds to the interval following the dfs number. Also, for the | |
925 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
926 | to the start of the following interval, not to the end of the current | |
927 | one). We use WORKLIST as a stack. */ | |
928 | worklist = VEC_alloc (int, heap, n_defs + 1); | |
929 | VEC_quick_push (int, worklist, 1); | |
930 | top = 1; | |
931 | n_defs = 1; | |
932 | for (i = 1; i < adef; i++) | |
933 | { | |
934 | b = defs[i].bb_index; | |
935 | if (b == top) | |
936 | { | |
937 | /* This is a closing element. Interval corresponding to the top | |
938 | of the stack after removing it follows. */ | |
939 | VEC_pop (int, worklist); | |
940 | top = VEC_index (int, worklist, VEC_length (int, worklist) - 1); | |
941 | defs[n_defs].bb_index = top; | |
942 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
943 | } | |
944 | else | |
945 | { | |
946 | /* Opening element. Nothing to do, just push it to the stack and move | |
947 | it to the correct position. */ | |
948 | defs[n_defs].bb_index = defs[i].bb_index; | |
949 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
950 | VEC_quick_push (int, worklist, b); | |
951 | top = b; | |
952 | } | |
953 | ||
954 | /* If this interval starts at the same point as the previous one, cancel | |
955 | the previous one. */ | |
956 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
957 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
958 | else | |
959 | n_defs++; | |
960 | } | |
961 | VEC_pop (int, worklist); | |
962 | gcc_assert (VEC_empty (int, worklist)); | |
963 | ||
964 | /* Now process the uses. */ | |
965 | live_phis = BITMAP_ALLOC (NULL); | |
966 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
967 | { | |
968 | VEC_safe_push (int, heap, worklist, i); | |
969 | } | |
970 | ||
971 | while (!VEC_empty (int, worklist)) | |
972 | { | |
973 | b = VEC_pop (int, worklist); | |
974 | if (b == ENTRY_BLOCK) | |
975 | continue; | |
976 | ||
977 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
978 | find the def that dominates the immediate dominator of USE_BB | |
979 | (the kill in USE_BB does not dominate the use). */ | |
980 | if (bitmap_bit_p (phis, b)) | |
981 | p = b; | |
982 | else | |
983 | { | |
984 | use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b)); | |
985 | p = find_dfsnum_interval (defs, n_defs, | |
986 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
987 | if (!bitmap_bit_p (phis, p)) | |
988 | continue; | |
989 | } | |
990 | ||
991 | /* If the phi node is already live, there is nothing to do. */ | |
992 | if (bitmap_bit_p (live_phis, p)) | |
993 | continue; | |
994 | ||
995 | /* Mark the phi as live, and add the new uses to the worklist. */ | |
996 | bitmap_set_bit (live_phis, p); | |
997 | def_bb = BASIC_BLOCK (p); | |
998 | FOR_EACH_EDGE (e, ei, def_bb->preds) | |
999 | { | |
1000 | u = e->src->index; | |
1001 | if (bitmap_bit_p (uses, u)) | |
1002 | continue; | |
1003 | ||
1e5787ef ZD |
1004 | /* In case there is a kill directly in the use block, do not record |
1005 | the use (this is also necessary for correctness, as we assume that | |
1006 | uses dominated by a def directly in their block have been filtered | |
1007 | out before). */ | |
1008 | if (bitmap_bit_p (kills, u)) | |
1009 | continue; | |
1010 | ||
f074ff6c ZD |
1011 | bitmap_set_bit (uses, u); |
1012 | VEC_safe_push (int, heap, worklist, u); | |
1013 | } | |
1014 | } | |
1015 | ||
1016 | VEC_free (int, heap, worklist); | |
1017 | bitmap_copy (phis, live_phis); | |
1018 | BITMAP_FREE (live_phis); | |
1019 | free (defs); | |
1020 | } | |
7256233c | 1021 | |
7256233c DN |
1022 | /* Return the set of blocks where variable VAR is defined and the blocks |
1023 | where VAR is live on entry (livein). Return NULL, if no entry is | |
1024 | found in DEF_BLOCKS. */ | |
1025 | ||
1026 | static inline struct def_blocks_d * | |
1027 | find_def_blocks_for (tree var) | |
1028 | { | |
1029 | struct def_blocks_d dm; | |
1030 | dm.var = var; | |
1031 | return (struct def_blocks_d *) htab_find (def_blocks, &dm); | |
1032 | } | |
1033 | ||
1034 | ||
0bca51f0 DN |
1035 | /* Retrieve or create a default definition for symbol SYM. */ |
1036 | ||
1037 | static inline tree | |
1038 | get_default_def_for (tree sym) | |
1039 | { | |
5cd4ec7f | 1040 | tree ddef = gimple_default_def (cfun, sym); |
0bca51f0 DN |
1041 | |
1042 | if (ddef == NULL_TREE) | |
1043 | { | |
726a989a | 1044 | ddef = make_ssa_name (sym, gimple_build_nop ()); |
0bca51f0 DN |
1045 | set_default_def (sym, ddef); |
1046 | } | |
1047 | ||
1048 | return ddef; | |
1049 | } | |
1050 | ||
1051 | ||
2ce79879 ZD |
1052 | /* Marks phi node PHI in basic block BB for rewrite. */ |
1053 | ||
1054 | static void | |
726a989a | 1055 | mark_phi_for_rewrite (basic_block bb, gimple phi) |
2ce79879 | 1056 | { |
726a989a | 1057 | gimple_vec phis; |
2ce79879 ZD |
1058 | unsigned i, idx = bb->index; |
1059 | ||
726a989a | 1060 | if (rewrite_uses_p (phi)) |
2ce79879 | 1061 | return; |
38635499 | 1062 | |
726a989a | 1063 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
1064 | |
1065 | if (!blocks_with_phis_to_rewrite) | |
1066 | return; | |
1067 | ||
1068 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
726a989a RB |
1069 | VEC_reserve (gimple_vec, heap, phis_to_rewrite, last_basic_block + 1); |
1070 | for (i = VEC_length (gimple_vec, phis_to_rewrite); i <= idx; i++) | |
1071 | VEC_quick_push (gimple_vec, phis_to_rewrite, NULL); | |
2ce79879 | 1072 | |
726a989a | 1073 | phis = VEC_index (gimple_vec, phis_to_rewrite, idx); |
2ce79879 | 1074 | if (!phis) |
726a989a | 1075 | phis = VEC_alloc (gimple, heap, 10); |
2ce79879 | 1076 | |
726a989a RB |
1077 | VEC_safe_push (gimple, heap, phis, phi); |
1078 | VEC_replace (gimple_vec, phis_to_rewrite, idx, phis); | |
2ce79879 ZD |
1079 | } |
1080 | ||
38635499 | 1081 | |
7256233c | 1082 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 1083 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
1084 | function assumes that the caller is incrementally updating the |
1085 | existing SSA form, in which case VAR may be an SSA name instead of | |
1086 | a symbol. | |
0bca51f0 DN |
1087 | |
1088 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
1089 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
1090 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
1091 | |
1092 | static void | |
0bca51f0 | 1093 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
1094 | { |
1095 | unsigned bb_index; | |
1096 | edge e; | |
726a989a | 1097 | gimple phi; |
7256233c DN |
1098 | basic_block bb; |
1099 | bitmap_iterator bi; | |
1100 | struct def_blocks_d *def_map; | |
1101 | ||
1102 | def_map = find_def_blocks_for (var); | |
0bca51f0 | 1103 | gcc_assert (def_map); |
7256233c DN |
1104 | |
1105 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
1106 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
1107 | ||
f074ff6c ZD |
1108 | /* Remove obviously useless phi nodes. */ |
1109 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
1110 | def_map->livein_blocks); | |
7256233c DN |
1111 | |
1112 | /* And insert the PHI nodes. */ | |
f074ff6c | 1113 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c DN |
1114 | { |
1115 | bb = BASIC_BLOCK (bb_index); | |
95dd3097 ZD |
1116 | if (update_p) |
1117 | mark_block_for_update (bb); | |
7256233c | 1118 | |
726a989a | 1119 | phi = NULL; |
38635499 DN |
1120 | |
1121 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 1122 | { |
84d65814 DN |
1123 | /* If we are rewriting SSA names, create the LHS of the PHI |
1124 | node by duplicating VAR. This is useful in the case of | |
1125 | pointers, to also duplicate pointer attributes (alias | |
1126 | information, in particular). */ | |
7256233c | 1127 | edge_iterator ei; |
84d65814 | 1128 | tree new_lhs; |
0bca51f0 | 1129 | |
38635499 | 1130 | gcc_assert (update_p); |
84d65814 | 1131 | phi = create_phi_node (var, bb); |
38635499 | 1132 | |
84d65814 | 1133 | new_lhs = duplicate_ssa_name (var, phi); |
726a989a | 1134 | gimple_phi_set_result (phi, new_lhs); |
84d65814 | 1135 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1136 | |
1137 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1138 | every argument so that rewrite_update_phi_arguments knows | |
1139 | which name is this PHI node replacing. If VAR is a | |
1140 | symbol marked for renaming, this is not necessary, the | |
1141 | renamer will use the symbol on the LHS to get its | |
1142 | reaching definition. */ | |
7256233c DN |
1143 | FOR_EACH_EDGE (e, ei, bb->preds) |
1144 | add_phi_arg (phi, var, e); | |
1145 | } | |
84d65814 DN |
1146 | else |
1147 | { | |
e24c4814 SB |
1148 | gcc_assert (DECL_P (var)); |
1149 | phi = create_phi_node (var, bb); | |
84d65814 | 1150 | } |
0bca51f0 DN |
1151 | |
1152 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1153 | set_register_defs (phi, true); |
2ce79879 | 1154 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1155 | } |
1156 | } | |
1157 | ||
1158 | ||
7256233c DN |
1159 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1160 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1161 | the flowgraph. */ |
7256233c DN |
1162 | |
1163 | static void | |
84d65814 | 1164 | insert_phi_nodes (bitmap *dfs) |
7256233c | 1165 | { |
a3648cfc DB |
1166 | referenced_var_iterator rvi; |
1167 | tree var; | |
7256233c DN |
1168 | |
1169 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
a3648cfc DB |
1170 | |
1171 | FOR_EACH_REFERENCED_VAR (var, rvi) | |
5f240ec4 | 1172 | { |
84d65814 DN |
1173 | struct def_blocks_d *def_map; |
1174 | bitmap idf; | |
0bca51f0 | 1175 | |
84d65814 DN |
1176 | def_map = find_def_blocks_for (var); |
1177 | if (def_map == NULL) | |
1178 | continue; | |
1179 | ||
1180 | if (get_phi_state (var) != NEED_PHI_STATE_NO) | |
1181 | { | |
38635499 | 1182 | idf = compute_idf (def_map->def_blocks, dfs); |
84d65814 DN |
1183 | insert_phi_nodes_for (var, idf, false); |
1184 | BITMAP_FREE (idf); | |
1185 | } | |
7256233c | 1186 | } |
5f240ec4 | 1187 | |
6de9cd9a DN |
1188 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1189 | } | |
1190 | ||
1191 | ||
38635499 DN |
1192 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1193 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1194 | |
cfaab3a9 | 1195 | static void |
38635499 | 1196 | register_new_def (tree def, tree sym) |
7256233c | 1197 | { |
7256233c DN |
1198 | tree currdef; |
1199 | ||
1200 | /* If this variable is set in a single basic block and all uses are | |
1201 | dominated by the set(s) in that single basic block, then there is | |
1202 | no reason to record anything for this variable in the block local | |
1203 | definition stacks. Doing so just wastes time and memory. | |
1204 | ||
1205 | This is the same test to prune the set of variables which may | |
1206 | need PHI nodes. So we just use that information since it's already | |
1207 | computed and available for us to use. */ | |
38635499 | 1208 | if (get_phi_state (sym) == NEED_PHI_STATE_NO) |
7256233c | 1209 | { |
38635499 | 1210 | set_current_def (sym, def); |
7256233c DN |
1211 | return; |
1212 | } | |
1213 | ||
38635499 | 1214 | currdef = get_current_def (sym); |
7256233c | 1215 | |
38635499 DN |
1216 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1217 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1218 | in the stack so that we know which symbol is being defined by | |
1219 | this SSA name when we unwind the stack. */ | |
1220 | if (currdef && !is_gimple_reg (sym)) | |
1221 | VEC_safe_push (tree, heap, block_defs_stack, sym); | |
7256233c | 1222 | |
38635499 DN |
1223 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1224 | stack is later used by the dominator tree callbacks to restore | |
1225 | the reaching definitions for all the variables defined in the | |
1226 | block after a recursive visit to all its immediately dominated | |
1227 | blocks. If there is no current reaching definition, then just | |
1228 | record the underlying _DECL node. */ | |
1229 | VEC_safe_push (tree, heap, block_defs_stack, currdef ? currdef : sym); | |
1230 | ||
1231 | /* Set the current reaching definition for SYM to be DEF. */ | |
1232 | set_current_def (sym, def); | |
7256233c DN |
1233 | } |
1234 | ||
1235 | ||
6de9cd9a DN |
1236 | /* Perform a depth-first traversal of the dominator tree looking for |
1237 | variables to rename. BB is the block where to start searching. | |
1238 | Renaming is a five step process: | |
1239 | ||
1240 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1241 | registered as the current definition for the corresponding variable. | |
1242 | ||
1243 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1244 | rewritten with their corresponding reaching definition. DEF and | |
1245 | VDEF targets are registered as new definitions. | |
1246 | ||
1247 | 3- All the PHI nodes in successor blocks of BB are visited. The | |
1248 | argument corresponding to BB is replaced with its current reaching | |
1249 | definition. | |
1250 | ||
1251 | 4- Recursively rewrite every dominator child block of BB. | |
1252 | ||
1253 | 5- Restore (in reverse order) the current reaching definition for every | |
1254 | new definition introduced in this block. This is done so that when | |
1255 | we return from the recursive call, all the current reaching | |
1256 | definitions are restored to the names that were valid in the | |
1257 | dominator parent of BB. */ | |
1258 | ||
6de9cd9a DN |
1259 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1260 | of reaching definitions for new SSA names produced in this block | |
1261 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1262 | block. */ | |
1263 | ||
1264 | static void | |
9fae925b JL |
1265 | rewrite_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1266 | basic_block bb) | |
6de9cd9a | 1267 | { |
726a989a RB |
1268 | gimple phi; |
1269 | gimple_stmt_iterator gsi; | |
6de9cd9a DN |
1270 | |
1271 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1272 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1273 | ||
9fae925b | 1274 | /* Mark the unwind point for this block. */ |
d4e6fecb | 1275 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); |
9fae925b | 1276 | |
6de9cd9a DN |
1277 | /* Step 1. Register new definitions for every PHI node in the block. |
1278 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1279 | node introduces a new version for the associated variable. */ | |
726a989a | 1280 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
6de9cd9a | 1281 | { |
726a989a RB |
1282 | tree result; |
1283 | ||
1284 | phi = gsi_stmt (gsi); | |
1285 | result = gimple_phi_result (phi); | |
38635499 DN |
1286 | gcc_assert (is_gimple_reg (result)); |
1287 | register_new_def (result, SSA_NAME_VAR (result)); | |
6de9cd9a DN |
1288 | } |
1289 | } | |
1290 | ||
5f240ec4 | 1291 | |
7256233c | 1292 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1293 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1294 | |
7256233c DN |
1295 | static tree |
1296 | get_reaching_def (tree var) | |
1297 | { | |
38635499 | 1298 | tree currdef; |
7256233c DN |
1299 | |
1300 | /* Lookup the current reaching definition for VAR. */ | |
38635499 | 1301 | currdef = get_current_def (var); |
5f240ec4 | 1302 | |
7256233c DN |
1303 | /* If there is no reaching definition for VAR, create and register a |
1304 | default definition for it (if needed). */ | |
38635499 | 1305 | if (currdef == NULL_TREE) |
7256233c | 1306 | { |
38635499 DN |
1307 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
1308 | currdef = get_default_def_for (sym); | |
1309 | set_current_def (var, currdef); | |
7256233c DN |
1310 | } |
1311 | ||
1312 | /* Return the current reaching definition for VAR, or the default | |
1313 | definition, if we had to create one. */ | |
38635499 | 1314 | return currdef; |
7256233c DN |
1315 | } |
1316 | ||
1317 | ||
1318 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in | |
1319 | the block with its immediate reaching definitions. Update the current | |
1320 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1321 | |
1322 | static void | |
7256233c | 1323 | rewrite_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
726a989a | 1324 | basic_block bb ATTRIBUTE_UNUSED, gimple_stmt_iterator si) |
5f240ec4 | 1325 | { |
726a989a | 1326 | gimple stmt; |
7256233c DN |
1327 | use_operand_p use_p; |
1328 | def_operand_p def_p; | |
1329 | ssa_op_iter iter; | |
1330 | ||
726a989a | 1331 | stmt = gsi_stmt (si); |
7256233c DN |
1332 | |
1333 | /* If mark_def_sites decided that we don't need to rewrite this | |
1334 | statement, ignore it. */ | |
95dd3097 | 1335 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1336 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1337 | return; |
5f240ec4 ZD |
1338 | |
1339 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1340 | { |
1341 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1342 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1343 | fprintf (dump_file, "\n"); |
1344 | } | |
5f240ec4 | 1345 | |
38635499 | 1346 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1347 | if (rewrite_uses_p (stmt)) |
38635499 | 1348 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) |
0bca51f0 DN |
1349 | { |
1350 | tree var = USE_FROM_PTR (use_p); | |
1351 | gcc_assert (DECL_P (var)); | |
1352 | SET_USE (use_p, get_reaching_def (var)); | |
1353 | } | |
5f240ec4 | 1354 | |
38635499 | 1355 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1356 | if (register_defs_p (stmt)) |
38635499 | 1357 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) |
0bca51f0 DN |
1358 | { |
1359 | tree var = DEF_FROM_PTR (def_p); | |
1360 | gcc_assert (DECL_P (var)); | |
1361 | SET_DEF (def_p, make_ssa_name (var, stmt)); | |
38635499 | 1362 | register_new_def (DEF_FROM_PTR (def_p), var); |
0bca51f0 | 1363 | } |
5f240ec4 | 1364 | } |
6de9cd9a | 1365 | |
7256233c | 1366 | |
6de9cd9a DN |
1367 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1368 | PHI nodes. For every PHI node found, add a new argument containing the | |
1369 | current reaching definition for the variable and the edge through which | |
471854f8 | 1370 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1371 | |
1372 | static void | |
1373 | rewrite_add_phi_arguments (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1374 | basic_block bb) | |
1375 | { | |
1376 | edge e; | |
628f6a4e | 1377 | edge_iterator ei; |
6de9cd9a | 1378 | |
628f6a4e | 1379 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1380 | { |
726a989a RB |
1381 | gimple phi; |
1382 | gimple_stmt_iterator gsi; | |
6de9cd9a | 1383 | |
726a989a RB |
1384 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1385 | gsi_next (&gsi)) | |
6de9cd9a DN |
1386 | { |
1387 | tree currdef; | |
726a989a RB |
1388 | phi = gsi_stmt (gsi); |
1389 | currdef = get_reaching_def (SSA_NAME_VAR (gimple_phi_result (phi))); | |
d2e398df | 1390 | add_phi_arg (phi, currdef, e); |
6de9cd9a DN |
1391 | } |
1392 | } | |
1393 | } | |
1394 | ||
7256233c | 1395 | |
38635499 DN |
1396 | /* Called after visiting all the statements in basic block BB and all |
1397 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a DN |
1398 | |
1399 | static void | |
9fae925b | 1400 | rewrite_finalize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
6de9cd9a DN |
1401 | basic_block bb ATTRIBUTE_UNUSED) |
1402 | { | |
9fae925b | 1403 | /* Restore CURRDEFS to its original state. */ |
d4e6fecb | 1404 | while (VEC_length (tree, block_defs_stack) > 0) |
6de9cd9a | 1405 | { |
d4e6fecb | 1406 | tree tmp = VEC_pop (tree, block_defs_stack); |
6de9cd9a DN |
1407 | tree saved_def, var; |
1408 | ||
9fae925b JL |
1409 | if (tmp == NULL_TREE) |
1410 | break; | |
1411 | ||
6de9cd9a DN |
1412 | if (TREE_CODE (tmp) == SSA_NAME) |
1413 | { | |
38635499 DN |
1414 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1415 | current definition of its underlying variable. Note that | |
1416 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1417 | being defined is stored in the next slot in the stack. | |
1418 | This mechanism is needed because an SSA name for a | |
1419 | non-register symbol may be the definition for more than | |
1420 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1421 | saved_def = tmp; |
1422 | var = SSA_NAME_VAR (saved_def); | |
38635499 DN |
1423 | if (!is_gimple_reg (var)) |
1424 | var = VEC_pop (tree, block_defs_stack); | |
6de9cd9a DN |
1425 | } |
1426 | else | |
1427 | { | |
38635499 DN |
1428 | /* If we recorded anything else, it must have been a _DECL |
1429 | node and its current reaching definition must have been | |
1430 | NULL. */ | |
6de9cd9a DN |
1431 | saved_def = NULL; |
1432 | var = tmp; | |
1433 | } | |
9fae925b | 1434 | |
5f240ec4 | 1435 | set_current_def (var, saved_def); |
6de9cd9a DN |
1436 | } |
1437 | } | |
1438 | ||
1439 | ||
38635499 DN |
1440 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1441 | ||
1442 | void | |
1443 | dump_decl_set (FILE *file, bitmap set) | |
1444 | { | |
1445 | if (set) | |
1446 | { | |
3b302421 RG |
1447 | bitmap_iterator bi; |
1448 | unsigned i; | |
38635499 DN |
1449 | |
1450 | fprintf (file, "{ "); | |
1451 | ||
3b302421 | 1452 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
38635499 | 1453 | { |
3b302421 | 1454 | print_generic_expr (file, referenced_var (i), 0); |
38635499 DN |
1455 | fprintf (file, " "); |
1456 | } | |
1457 | ||
1458 | fprintf (file, "}\n"); | |
1459 | } | |
1460 | else | |
1461 | fprintf (file, "NIL\n"); | |
1462 | } | |
1463 | ||
1464 | ||
1465 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ | |
1466 | ||
1467 | void | |
1468 | debug_decl_set (bitmap set) | |
1469 | { | |
1470 | dump_decl_set (stderr, set); | |
1471 | } | |
1472 | ||
1473 | ||
1474 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1475 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1476 | dumped. New levels are created when the dominator tree traversal | |
1477 | used for renaming enters a new sub-tree. */ | |
1478 | ||
1479 | void | |
1480 | dump_defs_stack (FILE *file, int n) | |
1481 | { | |
1482 | int i, j; | |
1483 | ||
1484 | fprintf (file, "\n\nRenaming stack"); | |
1485 | if (n > 0) | |
1486 | fprintf (file, " (up to %d levels)", n); | |
1487 | fprintf (file, "\n\n"); | |
1488 | ||
1489 | i = 1; | |
1490 | fprintf (file, "Level %d (current level)\n", i); | |
1491 | for (j = (int) VEC_length (tree, block_defs_stack) - 1; j >= 0; j--) | |
1492 | { | |
1493 | tree name, var; | |
1494 | ||
1495 | name = VEC_index (tree, block_defs_stack, j); | |
1496 | if (name == NULL_TREE) | |
1497 | { | |
1498 | i++; | |
1499 | if (n > 0 && i > n) | |
1500 | break; | |
1501 | fprintf (file, "\nLevel %d\n", i); | |
1502 | continue; | |
1503 | } | |
1504 | ||
1505 | if (DECL_P (name)) | |
1506 | { | |
1507 | var = name; | |
1508 | name = NULL_TREE; | |
1509 | } | |
1510 | else | |
1511 | { | |
1512 | var = SSA_NAME_VAR (name); | |
1513 | if (!is_gimple_reg (var)) | |
1514 | { | |
1515 | j--; | |
1516 | var = VEC_index (tree, block_defs_stack, j); | |
1517 | } | |
1518 | } | |
1519 | ||
1520 | fprintf (file, " Previous CURRDEF ("); | |
1521 | print_generic_expr (file, var, 0); | |
1522 | fprintf (file, ") = "); | |
1523 | if (name) | |
1524 | print_generic_expr (file, name, 0); | |
1525 | else | |
1526 | fprintf (file, "<NIL>"); | |
1527 | fprintf (file, "\n"); | |
1528 | } | |
1529 | } | |
1530 | ||
1531 | ||
1532 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1533 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1534 | dumped. New levels are created when the dominator tree traversal | |
1535 | used for renaming enters a new sub-tree. */ | |
1536 | ||
1537 | void | |
1538 | debug_defs_stack (int n) | |
1539 | { | |
1540 | dump_defs_stack (stderr, n); | |
1541 | } | |
1542 | ||
1543 | ||
1544 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1545 | ||
1546 | void | |
1547 | dump_currdefs (FILE *file) | |
1548 | { | |
1549 | referenced_var_iterator i; | |
1550 | tree var; | |
1551 | ||
1552 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); | |
1553 | FOR_EACH_REFERENCED_VAR (var, i) | |
1554 | if (syms_to_rename == NULL || bitmap_bit_p (syms_to_rename, DECL_UID (var))) | |
1555 | { | |
1556 | fprintf (file, "CURRDEF ("); | |
1557 | print_generic_expr (file, var, 0); | |
1558 | fprintf (file, ") = "); | |
1559 | if (get_current_def (var)) | |
1560 | print_generic_expr (file, get_current_def (var), 0); | |
1561 | else | |
1562 | fprintf (file, "<NIL>"); | |
1563 | fprintf (file, "\n"); | |
1564 | } | |
1565 | } | |
1566 | ||
1567 | ||
1568 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1569 | ||
1570 | void | |
1571 | debug_currdefs (void) | |
1572 | { | |
1573 | dump_currdefs (stderr); | |
1574 | } | |
1575 | ||
1576 | ||
6de9cd9a DN |
1577 | /* Dump SSA information to FILE. */ |
1578 | ||
1579 | void | |
1580 | dump_tree_ssa (FILE *file) | |
1581 | { | |
6de9cd9a | 1582 | const char *funcname |
673fda6b | 1583 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1584 | |
38635499 | 1585 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1586 | |
38635499 DN |
1587 | dump_def_blocks (file); |
1588 | dump_defs_stack (file, -1); | |
1589 | dump_currdefs (file); | |
1590 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1591 | } |
1592 | ||
1593 | ||
1594 | /* Dump SSA information to stderr. */ | |
1595 | ||
1596 | void | |
1597 | debug_tree_ssa (void) | |
1598 | { | |
1599 | dump_tree_ssa (stderr); | |
1600 | } | |
1601 | ||
1602 | ||
7256233c DN |
1603 | /* Dump statistics for the hash table HTAB. */ |
1604 | ||
1605 | static void | |
1606 | htab_statistics (FILE *file, htab_t htab) | |
1607 | { | |
1608 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1609 | (long) htab_size (htab), | |
1610 | (long) htab_elements (htab), | |
1611 | htab_collisions (htab)); | |
1612 | } | |
1613 | ||
1614 | ||
6de9cd9a DN |
1615 | /* Dump SSA statistics on FILE. */ |
1616 | ||
1617 | void | |
1618 | dump_tree_ssa_stats (FILE *file) | |
1619 | { | |
38635499 DN |
1620 | if (def_blocks || repl_tbl) |
1621 | fprintf (file, "\nHash table statistics:\n"); | |
6de9cd9a | 1622 | |
38635499 DN |
1623 | if (def_blocks) |
1624 | { | |
1625 | fprintf (file, " def_blocks: "); | |
1626 | htab_statistics (file, def_blocks); | |
1627 | } | |
6de9cd9a | 1628 | |
38635499 DN |
1629 | if (repl_tbl) |
1630 | { | |
1631 | fprintf (file, " repl_tbl: "); | |
1632 | htab_statistics (file, repl_tbl); | |
1633 | } | |
1634 | ||
1635 | if (def_blocks || repl_tbl) | |
1636 | fprintf (file, "\n"); | |
6de9cd9a DN |
1637 | } |
1638 | ||
1639 | ||
1640 | /* Dump SSA statistics on stderr. */ | |
1641 | ||
1642 | void | |
1643 | debug_tree_ssa_stats (void) | |
1644 | { | |
1645 | dump_tree_ssa_stats (stderr); | |
1646 | } | |
1647 | ||
1648 | ||
7256233c | 1649 | /* Hashing and equality functions for DEF_BLOCKS. */ |
6de9cd9a | 1650 | |
7256233c DN |
1651 | static hashval_t |
1652 | def_blocks_hash (const void *p) | |
6de9cd9a | 1653 | { |
7256233c DN |
1654 | return htab_hash_pointer |
1655 | ((const void *)((const struct def_blocks_d *)p)->var); | |
1656 | } | |
1657 | ||
1658 | static int | |
1659 | def_blocks_eq (const void *p1, const void *p2) | |
1660 | { | |
1661 | return ((const struct def_blocks_d *)p1)->var | |
1662 | == ((const struct def_blocks_d *)p2)->var; | |
6de9cd9a DN |
1663 | } |
1664 | ||
1665 | ||
7256233c | 1666 | /* Free memory allocated by one entry in DEF_BLOCKS. */ |
6de9cd9a DN |
1667 | |
1668 | static void | |
7256233c | 1669 | def_blocks_free (void *p) |
6de9cd9a | 1670 | { |
858904db | 1671 | struct def_blocks_d *entry = (struct def_blocks_d *) p; |
7256233c DN |
1672 | BITMAP_FREE (entry->def_blocks); |
1673 | BITMAP_FREE (entry->phi_blocks); | |
1674 | BITMAP_FREE (entry->livein_blocks); | |
1675 | free (entry); | |
1676 | } | |
6de9cd9a | 1677 | |
6de9cd9a | 1678 | |
7256233c | 1679 | /* Callback for htab_traverse to dump the DEF_BLOCKS hash table. */ |
6de9cd9a | 1680 | |
7256233c | 1681 | static int |
38635499 | 1682 | debug_def_blocks_r (void **slot, void *data) |
7256233c | 1683 | { |
38635499 | 1684 | FILE *file = (FILE *) data; |
7256233c DN |
1685 | struct def_blocks_d *db_p = (struct def_blocks_d *) *slot; |
1686 | ||
38635499 DN |
1687 | fprintf (file, "VAR: "); |
1688 | print_generic_expr (file, db_p->var, dump_flags); | |
1689 | bitmap_print (file, db_p->def_blocks, ", DEF_BLOCKS: { ", "}"); | |
1690 | bitmap_print (file, db_p->livein_blocks, ", LIVEIN_BLOCKS: { ", "}"); | |
1691 | bitmap_print (file, db_p->phi_blocks, ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1692 | |
7256233c DN |
1693 | return 1; |
1694 | } | |
6de9cd9a | 1695 | |
6de9cd9a | 1696 | |
38635499 DN |
1697 | /* Dump the DEF_BLOCKS hash table on FILE. */ |
1698 | ||
1699 | void | |
1700 | dump_def_blocks (FILE *file) | |
1701 | { | |
1702 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
1703 | if (def_blocks) | |
1704 | htab_traverse (def_blocks, debug_def_blocks_r, file); | |
1705 | } | |
1706 | ||
1707 | ||
7256233c | 1708 | /* Dump the DEF_BLOCKS hash table on stderr. */ |
6de9cd9a | 1709 | |
7256233c DN |
1710 | void |
1711 | debug_def_blocks (void) | |
1712 | { | |
38635499 | 1713 | dump_def_blocks (stderr); |
7256233c | 1714 | } |
6de9cd9a | 1715 | |
5f240ec4 | 1716 | |
0bca51f0 | 1717 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1718 | |
0bca51f0 DN |
1719 | static inline void |
1720 | register_new_update_single (tree new_name, tree old_name) | |
1721 | { | |
1722 | tree currdef = get_current_def (old_name); | |
5f240ec4 | 1723 | |
38635499 | 1724 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1725 | This stack is later used by the dominator tree callbacks to |
1726 | restore the reaching definitions for all the variables | |
1727 | defined in the block after a recursive visit to all its | |
1728 | immediately dominated blocks. */ | |
d4e6fecb NS |
1729 | VEC_reserve (tree, heap, block_defs_stack, 2); |
1730 | VEC_quick_push (tree, block_defs_stack, currdef); | |
1731 | VEC_quick_push (tree, block_defs_stack, old_name); | |
5f240ec4 | 1732 | |
0bca51f0 DN |
1733 | /* Set the current reaching definition for OLD_NAME to be |
1734 | NEW_NAME. */ | |
1735 | set_current_def (old_name, new_name); | |
1736 | } | |
7256233c | 1737 | |
6de9cd9a | 1738 | |
0bca51f0 DN |
1739 | /* Register NEW_NAME to be the new reaching definition for all the |
1740 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1741 | replace old SSA names with new ones. */ | |
7256233c | 1742 | |
0bca51f0 DN |
1743 | static inline void |
1744 | register_new_update_set (tree new_name, bitmap old_names) | |
1745 | { | |
1746 | bitmap_iterator bi; | |
1747 | unsigned i; | |
7256233c | 1748 | |
0bca51f0 DN |
1749 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1750 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1751 | } |
1752 | ||
7256233c | 1753 | |
0bca51f0 DN |
1754 | /* Initialization of block data structures for the incremental SSA |
1755 | update pass. Create a block local stack of reaching definitions | |
1756 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
1757 | new definitions for every PHI node in the block. */ | |
6de9cd9a DN |
1758 | |
1759 | static void | |
0bca51f0 DN |
1760 | rewrite_update_init_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1761 | basic_block bb) | |
6de9cd9a | 1762 | { |
0bca51f0 DN |
1763 | edge e; |
1764 | edge_iterator ei; | |
0bca51f0 | 1765 | bool is_abnormal_phi; |
726a989a | 1766 | gimple_stmt_iterator gsi; |
7d5f9cc6 | 1767 | |
0bca51f0 DN |
1768 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1769 | fprintf (dump_file, "\n\nRegistering new PHI nodes in block #%d\n\n", | |
1770 | bb->index); | |
6de9cd9a | 1771 | |
0bca51f0 | 1772 | /* Mark the unwind point for this block. */ |
d4e6fecb | 1773 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); |
6de9cd9a | 1774 | |
95dd3097 ZD |
1775 | if (!bitmap_bit_p (blocks_to_update, bb->index)) |
1776 | return; | |
1777 | ||
0bca51f0 DN |
1778 | /* Mark the LHS if any of the arguments flows through an abnormal |
1779 | edge. */ | |
1780 | is_abnormal_phi = false; | |
1781 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1782 | if (e->flags & EDGE_ABNORMAL) | |
1783 | { | |
1784 | is_abnormal_phi = true; | |
1785 | break; | |
1786 | } | |
6de9cd9a | 1787 | |
0bca51f0 DN |
1788 | /* If any of the PHI nodes is a replacement for a name in |
1789 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
1790 | register it as a new definition for its corresponding name. Also | |
1791 | register definitions for names whose underlying symbols are | |
1792 | marked for renaming. */ | |
726a989a | 1793 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
6de9cd9a | 1794 | { |
0bca51f0 | 1795 | tree lhs, lhs_sym; |
726a989a | 1796 | gimple phi = gsi_stmt (gsi); |
7256233c | 1797 | |
726a989a | 1798 | if (!register_defs_p (phi)) |
0bca51f0 DN |
1799 | continue; |
1800 | ||
726a989a | 1801 | lhs = gimple_phi_result (phi); |
0bca51f0 | 1802 | lhs_sym = SSA_NAME_VAR (lhs); |
7256233c | 1803 | |
0bca51f0 DN |
1804 | if (symbol_marked_for_renaming (lhs_sym)) |
1805 | register_new_update_single (lhs, lhs_sym); | |
1806 | else | |
1807 | { | |
38635499 | 1808 | |
0bca51f0 DN |
1809 | /* If LHS is a new name, register a new definition for all |
1810 | the names replaced by LHS. */ | |
1811 | if (is_new_name (lhs)) | |
1812 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
1813 | ||
1814 | /* If LHS is an OLD name, register it as a new definition | |
1815 | for itself. */ | |
1816 | if (is_old_name (lhs)) | |
1817 | register_new_update_single (lhs, lhs); | |
1818 | } | |
1819 | ||
1820 | if (is_abnormal_phi) | |
1821 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
1822 | } | |
6de9cd9a DN |
1823 | } |
1824 | ||
7d5f9cc6 | 1825 | |
0bca51f0 DN |
1826 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore |
1827 | the current reaching definition of every name re-written in BB to | |
1828 | the original reaching definition before visiting BB. This | |
1829 | unwinding must be done in the opposite order to what is done in | |
1830 | register_new_update_set. */ | |
1831 | ||
1832 | static void | |
1833 | rewrite_update_fini_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1834 | basic_block bb ATTRIBUTE_UNUSED) | |
1835 | { | |
d4e6fecb | 1836 | while (VEC_length (tree, block_defs_stack) > 0) |
0bca51f0 | 1837 | { |
d4e6fecb | 1838 | tree var = VEC_pop (tree, block_defs_stack); |
0bca51f0 DN |
1839 | tree saved_def; |
1840 | ||
1841 | /* NULL indicates the unwind stop point for this block (see | |
1842 | rewrite_update_init_block). */ | |
1843 | if (var == NULL) | |
1844 | return; | |
1845 | ||
d4e6fecb | 1846 | saved_def = VEC_pop (tree, block_defs_stack); |
0bca51f0 DN |
1847 | set_current_def (var, saved_def); |
1848 | } | |
1849 | } | |
1850 | ||
1851 | ||
84d65814 DN |
1852 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1853 | it is a symbol marked for renaming, replace it with USE_P's current | |
1854 | reaching definition. */ | |
1855 | ||
1856 | static inline void | |
1857 | maybe_replace_use (use_operand_p use_p) | |
1858 | { | |
1859 | tree rdef = NULL_TREE; | |
1860 | tree use = USE_FROM_PTR (use_p); | |
1861 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1862 | ||
1863 | if (symbol_marked_for_renaming (sym)) | |
1864 | rdef = get_reaching_def (sym); | |
1865 | else if (is_old_name (use)) | |
1866 | rdef = get_reaching_def (use); | |
1867 | ||
1868 | if (rdef && rdef != use) | |
1869 | SET_USE (use_p, rdef); | |
1870 | } | |
1871 | ||
1872 | ||
1873 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES | |
1874 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1875 | register it as the current definition for the names replaced by | |
1876 | DEF_P. */ | |
1877 | ||
1878 | static inline void | |
726a989a | 1879 | maybe_register_def (def_operand_p def_p, gimple stmt) |
84d65814 DN |
1880 | { |
1881 | tree def = DEF_FROM_PTR (def_p); | |
1882 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
1883 | ||
38635499 DN |
1884 | /* If DEF is a naked symbol that needs renaming, create a new |
1885 | name for it. */ | |
84d65814 DN |
1886 | if (symbol_marked_for_renaming (sym)) |
1887 | { | |
1888 | if (DECL_P (def)) | |
1889 | { | |
1890 | def = make_ssa_name (def, stmt); | |
1891 | SET_DEF (def_p, def); | |
1892 | } | |
1893 | ||
1894 | register_new_update_single (def, sym); | |
1895 | } | |
1896 | else | |
1897 | { | |
1898 | /* If DEF is a new name, register it as a new definition | |
1899 | for all the names replaced by DEF. */ | |
1900 | if (is_new_name (def)) | |
1901 | register_new_update_set (def, names_replaced_by (def)); | |
1902 | ||
1903 | /* If DEF is an old name, register DEF as a new | |
1904 | definition for itself. */ | |
1905 | if (is_old_name (def)) | |
1906 | register_new_update_single (def, def); | |
1907 | } | |
1908 | } | |
1909 | ||
1910 | ||
0bca51f0 DN |
1911 | /* Update every variable used in the statement pointed-to by SI. The |
1912 | statement is assumed to be in SSA form already. Names in | |
1913 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1914 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1915 | will be registered as a new definition for their corresponding name | |
1916 | in OLD_SSA_NAMES. */ | |
1917 | ||
1918 | static void | |
1919 | rewrite_update_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1920 | basic_block bb ATTRIBUTE_UNUSED, | |
726a989a | 1921 | gimple_stmt_iterator si) |
0bca51f0 | 1922 | { |
726a989a | 1923 | gimple stmt; |
0bca51f0 DN |
1924 | use_operand_p use_p; |
1925 | def_operand_p def_p; | |
1926 | ssa_op_iter iter; | |
1927 | ||
726a989a | 1928 | stmt = gsi_stmt (si); |
0bca51f0 | 1929 | |
95dd3097 ZD |
1930 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
1931 | ||
0bca51f0 | 1932 | /* Only update marked statements. */ |
726a989a | 1933 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
0bca51f0 DN |
1934 | return; |
1935 | ||
1936 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1937 | { | |
1938 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 1939 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
1940 | fprintf (dump_file, "\n"); |
1941 | } | |
1942 | ||
1943 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1944 | symbol is marked for renaming. */ | |
726a989a | 1945 | if (rewrite_uses_p (stmt)) |
0bca51f0 DN |
1946 | { |
1947 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
84d65814 | 1948 | maybe_replace_use (use_p); |
0bca51f0 DN |
1949 | |
1950 | if (need_to_update_vops_p) | |
38635499 | 1951 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_VIRTUAL_USES) |
84d65814 | 1952 | maybe_replace_use (use_p); |
0bca51f0 DN |
1953 | } |
1954 | ||
1955 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
1956 | Also register definitions for names whose underlying symbol is | |
1957 | marked for renaming. */ | |
726a989a | 1958 | if (register_defs_p (stmt)) |
0bca51f0 DN |
1959 | { |
1960 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) | |
84d65814 | 1961 | maybe_register_def (def_p, stmt); |
0bca51f0 DN |
1962 | |
1963 | if (need_to_update_vops_p) | |
1964 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_VIRTUAL_DEFS) | |
84d65814 | 1965 | maybe_register_def (def_p, stmt); |
0bca51f0 DN |
1966 | } |
1967 | } | |
1968 | ||
1969 | ||
1970 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
1971 | every PHI node found, check if any of its arguments is in | |
1972 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
1973 | definition, replace it. */ | |
1974 | ||
1975 | static void | |
1976 | rewrite_update_phi_arguments (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1977 | basic_block bb) | |
1978 | { | |
1979 | edge e; | |
1980 | edge_iterator ei; | |
2ce79879 | 1981 | unsigned i; |
0bca51f0 DN |
1982 | |
1983 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1984 | { | |
726a989a RB |
1985 | gimple phi; |
1986 | gimple_vec phis; | |
0bca51f0 | 1987 | |
2ce79879 ZD |
1988 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
1989 | continue; | |
1990 | ||
726a989a RB |
1991 | phis = VEC_index (gimple_vec, phis_to_rewrite, e->dest->index); |
1992 | for (i = 0; VEC_iterate (gimple, phis, i, phi); i++) | |
0bca51f0 | 1993 | { |
38635499 | 1994 | tree arg, lhs_sym; |
0bca51f0 DN |
1995 | use_operand_p arg_p; |
1996 | ||
726a989a | 1997 | gcc_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
1998 | |
1999 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2000 | arg = USE_FROM_PTR (arg_p); | |
2001 | ||
2002 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2003 | continue; | |
2004 | ||
726a989a | 2005 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 2006 | |
0bca51f0 DN |
2007 | if (arg == NULL_TREE) |
2008 | { | |
2009 | /* When updating a PHI node for a recently introduced | |
2010 | symbol we may find NULL arguments. That's why we | |
2011 | take the symbol from the LHS of the PHI node. */ | |
38635499 | 2012 | SET_USE (arg_p, get_reaching_def (lhs_sym)); |
0bca51f0 DN |
2013 | } |
2014 | else | |
2015 | { | |
2016 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2017 | ||
2018 | if (symbol_marked_for_renaming (sym)) | |
38635499 | 2019 | SET_USE (arg_p, get_reaching_def (sym)); |
0bca51f0 | 2020 | else if (is_old_name (arg)) |
38635499 | 2021 | SET_USE (arg_p, get_reaching_def (arg)); |
0bca51f0 DN |
2022 | } |
2023 | ||
2024 | if (e->flags & EDGE_ABNORMAL) | |
2025 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2026 | } | |
2027 | } | |
2028 | } | |
2029 | ||
2030 | ||
2031 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA | |
2032 | form. | |
2033 | ||
2034 | ENTRY indicates the block where to start. Every block dominated by | |
2035 | ENTRY will be rewritten. | |
2036 | ||
2037 | WHAT indicates what actions will be taken by the renamer (see enum | |
2038 | rewrite_mode). | |
2039 | ||
2040 | BLOCKS are the set of interesting blocks for the dominator walker | |
2041 | to process. If this set is NULL, then all the nodes dominated | |
2042 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2043 | are not present in BLOCKS are ignored. */ | |
2044 | ||
2045 | static void | |
2046 | rewrite_blocks (basic_block entry, enum rewrite_mode what, sbitmap blocks) | |
2047 | { | |
2048 | struct dom_walk_data walk_data; | |
2049 | ||
2050 | /* Rewrite all the basic blocks in the program. */ | |
2051 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2052 | ||
2053 | /* Setup callbacks for the generic dominator tree walker. */ | |
2054 | memset (&walk_data, 0, sizeof (walk_data)); | |
2055 | ||
2056 | walk_data.dom_direction = CDI_DOMINATORS; | |
2057 | walk_data.interesting_blocks = blocks; | |
2058 | ||
38635499 | 2059 | if (what == REWRITE_ALL) |
0bca51f0 | 2060 | walk_data.before_dom_children_before_stmts = rewrite_initialize_block; |
38635499 DN |
2061 | else |
2062 | walk_data.before_dom_children_before_stmts = rewrite_update_init_block; | |
0bca51f0 DN |
2063 | |
2064 | if (what == REWRITE_ALL) | |
2065 | walk_data.before_dom_children_walk_stmts = rewrite_stmt; | |
2066 | else if (what == REWRITE_UPDATE) | |
2067 | walk_data.before_dom_children_walk_stmts = rewrite_update_stmt; | |
2068 | else | |
2069 | gcc_unreachable (); | |
2070 | ||
2071 | if (what == REWRITE_ALL) | |
2072 | walk_data.before_dom_children_after_stmts = rewrite_add_phi_arguments; | |
2073 | else if (what == REWRITE_UPDATE) | |
2074 | walk_data.before_dom_children_after_stmts = rewrite_update_phi_arguments; | |
2075 | else | |
2076 | gcc_unreachable (); | |
2077 | ||
2078 | if (what == REWRITE_ALL) | |
2079 | walk_data.after_dom_children_after_stmts = rewrite_finalize_block; | |
2080 | else if (what == REWRITE_UPDATE) | |
2081 | walk_data.after_dom_children_after_stmts = rewrite_update_fini_block; | |
2082 | else | |
2083 | gcc_unreachable (); | |
2084 | ||
d4e6fecb | 2085 | block_defs_stack = VEC_alloc (tree, heap, 10); |
0bca51f0 DN |
2086 | |
2087 | /* Initialize the dominator walker. */ | |
2088 | init_walk_dominator_tree (&walk_data); | |
2089 | ||
2090 | /* Recursively walk the dominator tree rewriting each statement in | |
2091 | each basic block. */ | |
2092 | walk_dominator_tree (&walk_data, entry); | |
2093 | ||
2094 | /* Finalize the dominator walker. */ | |
2095 | fini_walk_dominator_tree (&walk_data); | |
2096 | ||
2097 | /* Debugging dumps. */ | |
2098 | if (dump_file && (dump_flags & TDF_STATS)) | |
2099 | { | |
2100 | dump_dfa_stats (dump_file); | |
2101 | if (def_blocks) | |
2102 | dump_tree_ssa_stats (dump_file); | |
2103 | } | |
0bca51f0 | 2104 | |
d4e6fecb | 2105 | VEC_free (tree, heap, block_defs_stack); |
0bca51f0 DN |
2106 | |
2107 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2108 | } | |
2109 | ||
2110 | ||
2111 | /* Block initialization routine for mark_def_sites. Clear the | |
2112 | KILLS bitmap at the start of each block. */ | |
6de9cd9a | 2113 | |
5f240ec4 | 2114 | static void |
7256233c DN |
2115 | mark_def_sites_initialize_block (struct dom_walk_data *walk_data, |
2116 | basic_block bb ATTRIBUTE_UNUSED) | |
5f240ec4 | 2117 | { |
38635499 DN |
2118 | struct mark_def_sites_global_data *gd; |
2119 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; | |
2120 | bitmap_clear (gd->kills); | |
7256233c | 2121 | } |
5f240ec4 | 2122 | |
5f240ec4 | 2123 | |
0bca51f0 DN |
2124 | /* Mark the definition site blocks for each variable, so that we know |
2125 | where the variable is actually live. | |
2126 | ||
2127 | INTERESTING_BLOCKS will be filled in with all the blocks that | |
2128 | should be processed by the renamer. It is assumed to be | |
2129 | initialized and zeroed by the caller. */ | |
5f240ec4 | 2130 | |
0bca51f0 DN |
2131 | static void |
2132 | mark_def_site_blocks (sbitmap interesting_blocks) | |
7256233c | 2133 | { |
7256233c DN |
2134 | struct dom_walk_data walk_data; |
2135 | struct mark_def_sites_global_data mark_def_sites_global_data; | |
5f240ec4 | 2136 | |
7256233c DN |
2137 | /* Setup callbacks for the generic dominator tree walker to find and |
2138 | mark definition sites. */ | |
2139 | walk_data.walk_stmts_backward = false; | |
2140 | walk_data.dom_direction = CDI_DOMINATORS; | |
2141 | walk_data.initialize_block_local_data = NULL; | |
2142 | walk_data.before_dom_children_before_stmts = mark_def_sites_initialize_block; | |
2143 | walk_data.before_dom_children_walk_stmts = mark_def_sites; | |
2144 | walk_data.before_dom_children_after_stmts = NULL; | |
2145 | walk_data.after_dom_children_before_stmts = NULL; | |
2146 | walk_data.after_dom_children_walk_stmts = NULL; | |
2147 | walk_data.after_dom_children_after_stmts = NULL; | |
0bca51f0 | 2148 | walk_data.interesting_blocks = NULL; |
5f240ec4 | 2149 | |
7256233c DN |
2150 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2151 | large enough to accommodate all the variables referenced in the | |
2152 | function, not just the ones we are renaming. */ | |
2153 | mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); | |
0bca51f0 DN |
2154 | |
2155 | /* Create the set of interesting blocks that will be filled by | |
2156 | mark_def_sites. */ | |
2157 | mark_def_sites_global_data.interesting_blocks = interesting_blocks; | |
7256233c | 2158 | walk_data.global_data = &mark_def_sites_global_data; |
6de9cd9a | 2159 | |
7256233c DN |
2160 | /* We do not have any local data. */ |
2161 | walk_data.block_local_data_size = 0; | |
2162 | ||
2163 | /* Initialize the dominator walker. */ | |
2164 | init_walk_dominator_tree (&walk_data); | |
2165 | ||
2166 | /* Recursively walk the dominator tree. */ | |
2167 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
2168 | ||
2169 | /* Finalize the dominator walker. */ | |
2170 | fini_walk_dominator_tree (&walk_data); | |
2171 | ||
2172 | /* We no longer need this bitmap, clear and free it. */ | |
2173 | BITMAP_FREE (mark_def_sites_global_data.kills); | |
6de9cd9a DN |
2174 | } |
2175 | ||
6de9cd9a | 2176 | |
38635499 DN |
2177 | /* Initialize internal data needed during renaming. */ |
2178 | ||
2179 | static void | |
2180 | init_ssa_renamer (void) | |
2181 | { | |
2182 | tree var; | |
2183 | referenced_var_iterator rvi; | |
2184 | ||
2185 | cfun->gimple_df->in_ssa_p = false; | |
2186 | ||
2187 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
2188 | gcc_assert (def_blocks == NULL); | |
2189 | def_blocks = htab_create (num_referenced_vars, def_blocks_hash, | |
2190 | def_blocks_eq, def_blocks_free); | |
2191 | ||
2192 | FOR_EACH_REFERENCED_VAR(var, rvi) | |
2193 | set_current_def (var, NULL_TREE); | |
2194 | } | |
2195 | ||
2196 | ||
2197 | /* Deallocate internal data structures used by the renamer. */ | |
2198 | ||
2199 | static void | |
2200 | fini_ssa_renamer (void) | |
2201 | { | |
2202 | if (def_blocks) | |
2203 | { | |
2204 | htab_delete (def_blocks); | |
2205 | def_blocks = NULL; | |
2206 | } | |
2207 | ||
2208 | cfun->gimple_df->in_ssa_p = true; | |
2209 | } | |
2210 | ||
7256233c | 2211 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2212 | proceeds in four main phases: |
6de9cd9a | 2213 | |
0bca51f0 DN |
2214 | 1- Compute dominance frontier and immediate dominators, needed to |
2215 | insert PHI nodes and rename the function in dominator tree | |
2216 | order. | |
6de9cd9a | 2217 | |
0bca51f0 | 2218 | 2- Find and mark all the blocks that define variables |
7256233c | 2219 | (mark_def_site_blocks). |
6de9cd9a | 2220 | |
0bca51f0 | 2221 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2222 | |
0bca51f0 | 2223 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2224 | |
77bfa778 | 2225 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2226 | (walk_dominator_tree). */ |
7256233c | 2227 | |
c2924966 | 2228 | static unsigned int |
0bca51f0 | 2229 | rewrite_into_ssa (void) |
6de9cd9a | 2230 | { |
7256233c DN |
2231 | bitmap *dfs; |
2232 | basic_block bb; | |
0bca51f0 | 2233 | sbitmap interesting_blocks; |
6de9cd9a | 2234 | |
7256233c | 2235 | timevar_push (TV_TREE_SSA_OTHER); |
6de9cd9a | 2236 | |
0bca51f0 DN |
2237 | /* Initialize operand data structures. */ |
2238 | init_ssa_operands (); | |
6de9cd9a | 2239 | |
38635499 DN |
2240 | /* Initialize internal data needed by the renamer. */ |
2241 | init_ssa_renamer (); | |
2242 | ||
0bca51f0 DN |
2243 | /* Initialize the set of interesting blocks. The callback |
2244 | mark_def_sites will add to this set those blocks that the renamer | |
2245 | should process. */ | |
2246 | interesting_blocks = sbitmap_alloc (last_basic_block); | |
2247 | sbitmap_zero (interesting_blocks); | |
6de9cd9a | 2248 | |
af5d3a18 | 2249 | /* Initialize dominance frontier. */ |
38635499 | 2250 | dfs = XNEWVEC (bitmap, last_basic_block); |
7256233c DN |
2251 | FOR_EACH_BB (bb) |
2252 | dfs[bb->index] = BITMAP_ALLOC (NULL); | |
6de9cd9a | 2253 | |
0bca51f0 DN |
2254 | /* 1- Compute dominance frontiers. */ |
2255 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2256 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2257 | |
0bca51f0 DN |
2258 | /* 2- Find and mark definition sites. */ |
2259 | mark_def_site_blocks (interesting_blocks); | |
2260 | ||
2261 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2262 | insert_phi_nodes (dfs); |
6de9cd9a | 2263 | |
0bca51f0 DN |
2264 | /* 4- Rename all the blocks. */ |
2265 | rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL, interesting_blocks); | |
6de9cd9a | 2266 | |
7256233c DN |
2267 | /* Free allocated memory. */ |
2268 | FOR_EACH_BB (bb) | |
2269 | BITMAP_FREE (dfs[bb->index]); | |
2270 | free (dfs); | |
0bca51f0 | 2271 | sbitmap_free (interesting_blocks); |
6de9cd9a | 2272 | |
38635499 DN |
2273 | fini_ssa_renamer (); |
2274 | ||
7256233c | 2275 | timevar_pop (TV_TREE_SSA_OTHER); |
c2924966 | 2276 | return 0; |
6de9cd9a DN |
2277 | } |
2278 | ||
2279 | ||
8ddbbcae | 2280 | struct gimple_opt_pass pass_build_ssa = |
6de9cd9a | 2281 | { |
8ddbbcae JH |
2282 | { |
2283 | GIMPLE_PASS, | |
7256233c DN |
2284 | "ssa", /* name */ |
2285 | NULL, /* gate */ | |
0bca51f0 | 2286 | rewrite_into_ssa, /* execute */ |
7256233c DN |
2287 | NULL, /* sub */ |
2288 | NULL, /* next */ | |
2289 | 0, /* static_pass_number */ | |
2290 | 0, /* tv_id */ | |
2291 | PROP_cfg | PROP_referenced_vars, /* properties_required */ | |
2292 | PROP_ssa, /* properties_provided */ | |
2293 | 0, /* properties_destroyed */ | |
2294 | 0, /* todo_flags_start */ | |
3f519b35 RG |
2295 | TODO_dump_func |
2296 | | TODO_verify_ssa | |
8ddbbcae JH |
2297 | | TODO_remove_unused_locals /* todo_flags_finish */ |
2298 | } | |
7256233c | 2299 | }; |
6de9cd9a DN |
2300 | |
2301 | ||
0bca51f0 DN |
2302 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2303 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2304 | |
0bca51f0 | 2305 | static void |
726a989a | 2306 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
6de9cd9a | 2307 | { |
95dd3097 | 2308 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2309 | set_register_defs (stmt, true); |
0bca51f0 DN |
2310 | |
2311 | if (insert_phi_p) | |
2312 | { | |
726a989a | 2313 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2314 | |
0bca51f0 DN |
2315 | set_def_block (var, bb, is_phi_p); |
2316 | ||
2317 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2318 | site for both itself and all the old names replaced by it. */ | |
2319 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2320 | { | |
2321 | bitmap_iterator bi; | |
2322 | unsigned i; | |
2323 | bitmap set = names_replaced_by (var); | |
2324 | if (set) | |
2325 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2326 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2327 | } | |
2328 | } | |
2329 | } | |
2330 | ||
2331 | ||
2332 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2333 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2334 | nodes. */ |
0bca51f0 DN |
2335 | |
2336 | static inline void | |
726a989a | 2337 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
0bca51f0 | 2338 | { |
726a989a | 2339 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2340 | |
95dd3097 ZD |
2341 | mark_block_for_update (def_bb); |
2342 | mark_block_for_update (bb); | |
2343 | ||
726a989a | 2344 | if (gimple_code (stmt) == GIMPLE_PHI) |
2ce79879 ZD |
2345 | mark_phi_for_rewrite (def_bb, stmt); |
2346 | else | |
726a989a | 2347 | set_rewrite_uses (stmt, true); |
0bca51f0 DN |
2348 | |
2349 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2350 | to BB. Note that we cannot just use the block holding VAR's | |
2351 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2352 | it will have several definitions (itself and all the names that | |
2353 | replace it). */ | |
2354 | if (insert_phi_p) | |
2355 | { | |
84d65814 | 2356 | struct def_blocks_d *db_p = get_def_blocks_for (var); |
0bca51f0 DN |
2357 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2358 | set_livein_block (var, bb); | |
2359 | } | |
2360 | } | |
2361 | ||
2362 | ||
0bca51f0 | 2363 | /* Do a dominator walk starting at BB processing statements that |
84d65814 DN |
2364 | reference symbols in SYMS_TO_RENAME. This is very similar to |
2365 | mark_def_sites, but the scan handles statements whose operands may | |
95dd3097 | 2366 | already be SSA names. |
0bca51f0 | 2367 | |
84d65814 DN |
2368 | If INSERT_PHI_P is true, mark those uses as live in the |
2369 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2370 | algorithm to make PHI pruning decisions. |
2371 | ||
2372 | FIXME. Most of this would be unnecessary if we could associate a | |
2373 | symbol to all the SSA names that reference it. But that | |
2374 | sounds like it would be expensive to maintain. Still, it | |
2375 | would be interesting to see if it makes better sense to do | |
2376 | that. */ | |
0bca51f0 DN |
2377 | |
2378 | static void | |
95dd3097 | 2379 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2380 | { |
2381 | basic_block son; | |
726a989a | 2382 | gimple_stmt_iterator si; |
f074ff6c ZD |
2383 | edge e; |
2384 | edge_iterator ei; | |
0bca51f0 | 2385 | |
95dd3097 ZD |
2386 | mark_block_for_update (bb); |
2387 | ||
0bca51f0 | 2388 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2389 | the symbols that we are interested in. */ |
726a989a | 2390 | for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2391 | { |
726a989a RB |
2392 | gimple phi = gsi_stmt (si); |
2393 | tree lhs_sym, lhs = gimple_phi_result (phi); | |
0bca51f0 | 2394 | |
0bca51f0 DN |
2395 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
2396 | ||
f074ff6c ZD |
2397 | if (!symbol_marked_for_renaming (lhs_sym)) |
2398 | continue; | |
726a989a | 2399 | |
f074ff6c ZD |
2400 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2401 | ||
2402 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2403 | to process the arguments of the phi nodes of the successor edges of | |
2404 | BB at the end of prepare_block_for_update, however, that turns out | |
2405 | to be significantly more expensive. Doing it here is conservatively | |
2406 | correct -- it may only cause us to believe a value to be live in a | |
2407 | block that also contains its definition, and thus insert a few more | |
2408 | phi nodes for it. */ | |
2409 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2410 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2411 | } |
2412 | ||
2413 | /* Process the statements. */ | |
726a989a | 2414 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2415 | { |
726a989a | 2416 | gimple stmt; |
0bca51f0 DN |
2417 | ssa_op_iter i; |
2418 | use_operand_p use_p; | |
2419 | def_operand_p def_p; | |
2420 | ||
726a989a | 2421 | stmt = gsi_stmt (si); |
0bca51f0 | 2422 | |
38635499 | 2423 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) |
0bca51f0 DN |
2424 | { |
2425 | tree use = USE_FROM_PTR (use_p); | |
2426 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
84d65814 | 2427 | if (symbol_marked_for_renaming (sym)) |
38635499 | 2428 | mark_use_interesting (sym, stmt, bb, insert_phi_p); |
0bca51f0 DN |
2429 | } |
2430 | ||
38635499 | 2431 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
2432 | { |
2433 | tree def = DEF_FROM_PTR (def_p); | |
2434 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
0bca51f0 | 2435 | if (symbol_marked_for_renaming (sym)) |
38635499 | 2436 | mark_def_interesting (sym, stmt, bb, insert_phi_p); |
0bca51f0 DN |
2437 | } |
2438 | } | |
2439 | ||
2440 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2441 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2442 | son; |
2443 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2444 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2445 | } |
2446 | ||
2447 | ||
2448 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2449 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2450 | prepare_names_to_update. */ | |
2451 | ||
2452 | static void | |
95dd3097 | 2453 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2454 | { |
2455 | use_operand_p use_p; | |
2456 | imm_use_iterator iter; | |
2457 | ||
2458 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2459 | { | |
726a989a RB |
2460 | gimple stmt = USE_STMT (use_p); |
2461 | basic_block bb = gimple_bb (stmt); | |
84d65814 | 2462 | |
726a989a | 2463 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2464 | { |
f074ff6c | 2465 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
726a989a | 2466 | edge e = gimple_phi_arg_edge (stmt, ix); |
f074ff6c | 2467 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2468 | } |
2469 | else | |
2470 | { | |
2471 | /* For regular statements, mark this as an interesting use | |
2472 | for NAME. */ | |
95dd3097 | 2473 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2474 | } |
2475 | } | |
0bca51f0 DN |
2476 | } |
2477 | ||
2478 | ||
84d65814 DN |
2479 | /* Helper for prepare_names_to_update. Mark the definition site for |
2480 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2481 | prepare_names_to_update. */ | |
0bca51f0 DN |
2482 | |
2483 | static void | |
95dd3097 | 2484 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2485 | { |
726a989a | 2486 | gimple stmt; |
0bca51f0 DN |
2487 | basic_block bb; |
2488 | ||
0bca51f0 DN |
2489 | gcc_assert (names_to_release == NULL |
2490 | || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name))); | |
2491 | ||
2492 | stmt = SSA_NAME_DEF_STMT (name); | |
726a989a | 2493 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2494 | if (bb) |
2495 | { | |
2496 | gcc_assert (bb->index < last_basic_block); | |
95dd3097 ZD |
2497 | mark_block_for_update (bb); |
2498 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2499 | } |
2500 | } | |
2501 | ||
2502 | ||
84d65814 | 2503 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2504 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2505 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2506 | |
2507 | static void | |
95dd3097 | 2508 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2509 | { |
dfea6c85 | 2510 | unsigned i = 0; |
0bca51f0 | 2511 | bitmap_iterator bi; |
b6e7e9af | 2512 | sbitmap_iterator sbi; |
0bca51f0 DN |
2513 | |
2514 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2515 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2516 | defining basic block (which most likely doesn't exist). Notice | |
2517 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2518 | want to replace existing instances. */ | |
2519 | if (names_to_release) | |
2520 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2521 | RESET_BIT (new_ssa_names, i); | |
2522 | ||
84d65814 DN |
2523 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2524 | names may be considered to be live-in on blocks that contain | |
2525 | definitions for their replacements. */ | |
b6e7e9af | 2526 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2527 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2528 | |
0bca51f0 DN |
2529 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2530 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
b6e7e9af | 2531 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2532 | { |
2533 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2534 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2535 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2536 | } |
0bca51f0 DN |
2537 | } |
2538 | ||
2539 | ||
2540 | /* Dump all the names replaced by NAME to FILE. */ | |
2541 | ||
2542 | void | |
2543 | dump_names_replaced_by (FILE *file, tree name) | |
2544 | { | |
2545 | unsigned i; | |
2546 | bitmap old_set; | |
2547 | bitmap_iterator bi; | |
2548 | ||
2549 | print_generic_expr (file, name, 0); | |
2550 | fprintf (file, " -> { "); | |
2551 | ||
2552 | old_set = names_replaced_by (name); | |
2553 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2554 | { | |
2555 | print_generic_expr (file, ssa_name (i), 0); | |
2556 | fprintf (file, " "); | |
2557 | } | |
2558 | ||
2559 | fprintf (file, "}\n"); | |
2560 | } | |
2561 | ||
2562 | ||
2563 | /* Dump all the names replaced by NAME to stderr. */ | |
2564 | ||
2565 | void | |
2566 | debug_names_replaced_by (tree name) | |
2567 | { | |
2568 | dump_names_replaced_by (stderr, name); | |
2569 | } | |
2570 | ||
2571 | ||
84d65814 | 2572 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2573 | |
2574 | void | |
84d65814 | 2575 | dump_update_ssa (FILE *file) |
0bca51f0 | 2576 | { |
dfea6c85 | 2577 | unsigned i = 0; |
0bca51f0 DN |
2578 | bitmap_iterator bi; |
2579 | ||
2580 | if (!need_ssa_update_p ()) | |
2581 | return; | |
2582 | ||
2583 | if (new_ssa_names && sbitmap_first_set_bit (new_ssa_names) >= 0) | |
2584 | { | |
b6e7e9af KH |
2585 | sbitmap_iterator sbi; |
2586 | ||
0bca51f0 DN |
2587 | fprintf (file, "\nSSA replacement table\n"); |
2588 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2589 | "O_1, ..., O_j\n\n"); | |
2590 | ||
b6e7e9af KH |
2591 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
2592 | dump_names_replaced_by (file, ssa_name (i)); | |
84d65814 DN |
2593 | |
2594 | fprintf (file, "\n"); | |
2595 | fprintf (file, "Number of virtual NEW -> OLD mappings: %7u\n", | |
2596 | update_ssa_stats.num_virtual_mappings); | |
2597 | fprintf (file, "Number of real NEW -> OLD mappings: %7u\n", | |
2598 | update_ssa_stats.num_total_mappings | |
2599 | - update_ssa_stats.num_virtual_mappings); | |
2600 | fprintf (file, "Number of total NEW -> OLD mappings: %7u\n", | |
2601 | update_ssa_stats.num_total_mappings); | |
2602 | ||
2603 | fprintf (file, "\nNumber of virtual symbols: %u\n", | |
2604 | update_ssa_stats.num_virtual_symbols); | |
0bca51f0 DN |
2605 | } |
2606 | ||
2607 | if (syms_to_rename && !bitmap_empty_p (syms_to_rename)) | |
2608 | { | |
2609 | fprintf (file, "\n\nSymbols to be put in SSA form\n\n"); | |
38635499 | 2610 | dump_decl_set (file, syms_to_rename); |
0bca51f0 DN |
2611 | } |
2612 | ||
0bca51f0 DN |
2613 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2614 | { | |
2615 | fprintf (file, "\n\nSSA names to release after updating the SSA web\n\n"); | |
2616 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2617 | { | |
2618 | print_generic_expr (file, ssa_name (i), 0); | |
2619 | fprintf (file, " "); | |
2620 | } | |
2621 | } | |
2622 | ||
2623 | fprintf (file, "\n\n"); | |
2624 | } | |
2625 | ||
2626 | ||
84d65814 | 2627 | /* Dump SSA update information to stderr. */ |
0bca51f0 DN |
2628 | |
2629 | void | |
84d65814 | 2630 | debug_update_ssa (void) |
0bca51f0 | 2631 | { |
84d65814 | 2632 | dump_update_ssa (stderr); |
0bca51f0 DN |
2633 | } |
2634 | ||
2635 | ||
2636 | /* Initialize data structures used for incremental SSA updates. */ | |
2637 | ||
2638 | static void | |
2639 | init_update_ssa (void) | |
2640 | { | |
84d65814 | 2641 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2642 | add_new_name_mapping are typically done after creating new SSA |
2643 | names, so we'll need to reallocate these arrays. */ | |
2644 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2645 | sbitmap_zero (old_ssa_names); | |
2646 | ||
2647 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2648 | sbitmap_zero (new_ssa_names); | |
2649 | ||
2650 | repl_tbl = htab_create (20, repl_map_hash, repl_map_eq, repl_map_free); | |
2651 | need_to_initialize_update_ssa_p = false; | |
2652 | need_to_update_vops_p = false; | |
0bca51f0 | 2653 | syms_to_rename = BITMAP_ALLOC (NULL); |
38635499 DN |
2654 | regs_to_rename = BITMAP_ALLOC (NULL); |
2655 | mem_syms_to_rename = BITMAP_ALLOC (NULL); | |
0bca51f0 | 2656 | names_to_release = NULL; |
84d65814 DN |
2657 | memset (&update_ssa_stats, 0, sizeof (update_ssa_stats)); |
2658 | update_ssa_stats.virtual_symbols = BITMAP_ALLOC (NULL); | |
0bca51f0 DN |
2659 | } |
2660 | ||
2661 | ||
2662 | /* Deallocate data structures used for incremental SSA updates. */ | |
2663 | ||
84d65814 | 2664 | void |
0bca51f0 DN |
2665 | delete_update_ssa (void) |
2666 | { | |
2667 | unsigned i; | |
2668 | bitmap_iterator bi; | |
2669 | ||
2670 | sbitmap_free (old_ssa_names); | |
2671 | old_ssa_names = NULL; | |
2672 | ||
2673 | sbitmap_free (new_ssa_names); | |
2674 | new_ssa_names = NULL; | |
2675 | ||
2676 | htab_delete (repl_tbl); | |
2677 | repl_tbl = NULL; | |
2678 | ||
2679 | need_to_initialize_update_ssa_p = true; | |
2680 | need_to_update_vops_p = false; | |
0bca51f0 | 2681 | BITMAP_FREE (syms_to_rename); |
38635499 DN |
2682 | BITMAP_FREE (regs_to_rename); |
2683 | BITMAP_FREE (mem_syms_to_rename); | |
84d65814 | 2684 | BITMAP_FREE (update_ssa_stats.virtual_symbols); |
0bca51f0 DN |
2685 | |
2686 | if (names_to_release) | |
2687 | { | |
2688 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2689 | release_ssa_name (ssa_name (i)); | |
2690 | BITMAP_FREE (names_to_release); | |
2691 | } | |
2692 | ||
95dd3097 | 2693 | clear_ssa_name_info (); |
38635499 DN |
2694 | |
2695 | fini_ssa_renamer (); | |
2696 | ||
2697 | if (blocks_with_phis_to_rewrite) | |
2698 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2699 | { | |
726a989a | 2700 | gimple_vec phis = VEC_index (gimple_vec, phis_to_rewrite, i); |
38635499 | 2701 | |
726a989a RB |
2702 | VEC_free (gimple, heap, phis); |
2703 | VEC_replace (gimple_vec, phis_to_rewrite, i, NULL); | |
38635499 DN |
2704 | } |
2705 | ||
2706 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2707 | BITMAP_FREE (blocks_to_update); | |
0bca51f0 DN |
2708 | } |
2709 | ||
2710 | ||
2711 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
2712 | operand pointed to by DEF_P with the newly created name. Return | |
2713 | the new name and register the replacement mapping <NEW, OLD> in | |
2714 | update_ssa's tables. */ | |
2715 | ||
2716 | tree | |
726a989a | 2717 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
0bca51f0 DN |
2718 | { |
2719 | tree new_name = duplicate_ssa_name (old_name, stmt); | |
2720 | ||
2721 | SET_DEF (def, new_name); | |
2722 | ||
726a989a | 2723 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 DN |
2724 | { |
2725 | edge e; | |
2726 | edge_iterator ei; | |
726a989a | 2727 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2728 | |
2729 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
2730 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2731 | if (e->flags & EDGE_ABNORMAL) | |
2732 | { | |
2733 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = 1; | |
2734 | break; | |
2735 | } | |
2736 | } | |
2737 | ||
2738 | register_new_name_mapping (new_name, old_name); | |
2739 | ||
2740 | /* For the benefit of passes that will be updating the SSA form on | |
2741 | their own, set the current reaching definition of OLD_NAME to be | |
2742 | NEW_NAME. */ | |
2743 | set_current_def (old_name, new_name); | |
2744 | ||
2745 | return new_name; | |
2746 | } | |
2747 | ||
2748 | ||
2749 | /* Register name NEW to be a replacement for name OLD. This function | |
2750 | must be called for every replacement that should be performed by | |
2751 | update_ssa. */ | |
2752 | ||
2753 | void | |
82d6e6fc | 2754 | register_new_name_mapping (tree new_Tree ATTRIBUTE_UNUSED, tree old ATTRIBUTE_UNUSED) |
0bca51f0 DN |
2755 | { |
2756 | if (need_to_initialize_update_ssa_p) | |
2757 | init_update_ssa (); | |
2758 | ||
82d6e6fc | 2759 | add_new_name_mapping (new_Tree, old); |
0bca51f0 DN |
2760 | } |
2761 | ||
2762 | ||
2763 | /* Register symbol SYM to be renamed by update_ssa. */ | |
2764 | ||
2765 | void | |
2766 | mark_sym_for_renaming (tree sym) | |
2767 | { | |
2768 | if (need_to_initialize_update_ssa_p) | |
2769 | init_update_ssa (); | |
2770 | ||
a3648cfc | 2771 | bitmap_set_bit (syms_to_rename, DECL_UID (sym)); |
0bca51f0 DN |
2772 | |
2773 | if (!is_gimple_reg (sym)) | |
38635499 DN |
2774 | { |
2775 | need_to_update_vops_p = true; | |
2776 | if (memory_partition (sym)) | |
2777 | bitmap_set_bit (syms_to_rename, DECL_UID (memory_partition (sym))); | |
2778 | } | |
0bca51f0 DN |
2779 | } |
2780 | ||
2781 | ||
2782 | /* Register all the symbols in SET to be renamed by update_ssa. */ | |
2783 | ||
2784 | void | |
2785 | mark_set_for_renaming (bitmap set) | |
2786 | { | |
2787 | bitmap_iterator bi; | |
2788 | unsigned i; | |
2789 | ||
38635499 | 2790 | if (set == NULL || bitmap_empty_p (set)) |
84d65814 DN |
2791 | return; |
2792 | ||
0bca51f0 DN |
2793 | if (need_to_initialize_update_ssa_p) |
2794 | init_update_ssa (); | |
2795 | ||
0bca51f0 | 2796 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
38635499 | 2797 | mark_sym_for_renaming (referenced_var (i)); |
0bca51f0 DN |
2798 | } |
2799 | ||
2800 | ||
2801 | /* Return true if there is any work to be done by update_ssa. */ | |
2802 | ||
2803 | bool | |
2804 | need_ssa_update_p (void) | |
2805 | { | |
2806 | return syms_to_rename || old_ssa_names || new_ssa_names; | |
2807 | } | |
2808 | ||
8f8bb1d2 ZD |
2809 | /* Return true if SSA name mappings have been registered for SSA updating. */ |
2810 | ||
2811 | bool | |
2812 | name_mappings_registered_p (void) | |
2813 | { | |
2814 | return repl_tbl && htab_elements (repl_tbl) > 0; | |
2815 | } | |
0bca51f0 DN |
2816 | |
2817 | /* Return true if name N has been registered in the replacement table. */ | |
2818 | ||
2819 | bool | |
726a989a | 2820 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 DN |
2821 | { |
2822 | if (!need_ssa_update_p ()) | |
2823 | return false; | |
2824 | ||
2825 | return is_new_name (n) | |
2826 | || is_old_name (n) | |
2827 | || symbol_marked_for_renaming (SSA_NAME_VAR (n)); | |
2828 | } | |
2829 | ||
2830 | ||
2831 | /* Return the set of all the SSA names marked to be replaced. */ | |
2832 | ||
2833 | bitmap | |
2834 | ssa_names_to_replace (void) | |
2835 | { | |
dfea6c85 | 2836 | unsigned i = 0; |
0bca51f0 | 2837 | bitmap ret; |
b6e7e9af | 2838 | sbitmap_iterator sbi; |
0bca51f0 DN |
2839 | |
2840 | ret = BITMAP_ALLOC (NULL); | |
b6e7e9af KH |
2841 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
2842 | bitmap_set_bit (ret, i); | |
0bca51f0 | 2843 | |
0bca51f0 DN |
2844 | return ret; |
2845 | } | |
2846 | ||
2847 | ||
2848 | /* Mark NAME to be released after update_ssa has finished. */ | |
2849 | ||
2850 | void | |
2851 | release_ssa_name_after_update_ssa (tree name) | |
2852 | { | |
2853 | gcc_assert (!need_to_initialize_update_ssa_p); | |
2854 | ||
2855 | if (names_to_release == NULL) | |
2856 | names_to_release = BITMAP_ALLOC (NULL); | |
2857 | ||
2858 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2859 | } | |
2860 | ||
2861 | ||
2862 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2863 | frontier information. BLOCKS is the set of blocks to be updated. | |
2864 | ||
2865 | This is slightly different than the regular PHI insertion | |
2866 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2867 | real names (i.e., GIMPLE registers) are inserted: | |
2868 | ||
2869 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI | |
2870 | nodes inside the region affected by the block that defines VAR | |
2871 | and the blocks that define all its replacements. All these | |
84d65814 | 2872 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
2873 | |
2874 | First, we compute the entry point to the region (ENTRY). This is | |
2875 | given by the nearest common dominator to all the definition | |
2876 | blocks. When computing the iterated dominance frontier (IDF), any | |
2877 | block not strictly dominated by ENTRY is ignored. | |
2878 | ||
2879 | We then call the standard PHI insertion algorithm with the pruned | |
2880 | IDF. | |
2881 | ||
2882 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
2883 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
2884 | ||
2885 | static void | |
2886 | insert_updated_phi_nodes_for (tree var, bitmap *dfs, bitmap blocks, | |
2887 | unsigned update_flags) | |
2888 | { | |
2889 | basic_block entry; | |
2890 | struct def_blocks_d *db; | |
2891 | bitmap idf, pruned_idf; | |
2892 | bitmap_iterator bi; | |
2893 | unsigned i; | |
2894 | ||
2895 | #if defined ENABLE_CHECKING | |
2896 | if (TREE_CODE (var) == SSA_NAME) | |
2897 | gcc_assert (is_old_name (var)); | |
2898 | else | |
2899 | gcc_assert (symbol_marked_for_renaming (var)); | |
2900 | #endif | |
2901 | ||
2902 | /* Get all the definition sites for VAR. */ | |
2903 | db = find_def_blocks_for (var); | |
2904 | ||
2905 | /* No need to do anything if there were no definitions to VAR. */ | |
2906 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
2907 | return; | |
2908 | ||
2909 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 2910 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
2911 | pruned_idf = BITMAP_ALLOC (NULL); |
2912 | ||
2913 | if (TREE_CODE (var) == SSA_NAME) | |
2914 | { | |
2915 | if (update_flags == TODO_update_ssa) | |
2916 | { | |
2917 | /* If doing regular SSA updates for GIMPLE registers, we are | |
2918 | only interested in IDF blocks dominated by the nearest | |
2919 | common dominator of all the definition blocks. */ | |
2920 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
2921 | db->def_blocks); | |
0bca51f0 DN |
2922 | if (entry != ENTRY_BLOCK_PTR) |
2923 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) | |
2924 | if (BASIC_BLOCK (i) != entry | |
2925 | && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) | |
2926 | bitmap_set_bit (pruned_idf, i); | |
2927 | } | |
2928 | else | |
2929 | { | |
2930 | /* Otherwise, do not prune the IDF for VAR. */ | |
2931 | gcc_assert (update_flags == TODO_update_ssa_full_phi); | |
2932 | bitmap_copy (pruned_idf, idf); | |
2933 | } | |
2934 | } | |
2935 | else | |
2936 | { | |
2937 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
2938 | for the first time, so we need to compute the full IDF for | |
2939 | it. */ | |
2940 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
2941 | } |
2942 | ||
2943 | if (!bitmap_empty_p (pruned_idf)) | |
2944 | { | |
2945 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
2946 | are included in the region to be updated. The feeding blocks | |
2947 | are important to guarantee that the PHI arguments are renamed | |
2948 | properly. */ | |
38635499 DN |
2949 | |
2950 | /* FIXME, this is not needed if we are updating symbols. We are | |
2951 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
2952 | bitmap_ior_into (blocks, pruned_idf); |
2953 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
2954 | { | |
2955 | edge e; | |
2956 | edge_iterator ei; | |
2957 | basic_block bb = BASIC_BLOCK (i); | |
2958 | ||
2959 | FOR_EACH_EDGE (e, ei, bb->preds) | |
2960 | if (e->src->index >= 0) | |
2961 | bitmap_set_bit (blocks, e->src->index); | |
2962 | } | |
2963 | ||
2964 | insert_phi_nodes_for (var, pruned_idf, true); | |
2965 | } | |
2966 | ||
2967 | BITMAP_FREE (pruned_idf); | |
2968 | BITMAP_FREE (idf); | |
2969 | } | |
2970 | ||
2971 | ||
84d65814 DN |
2972 | /* Heuristic to determine whether SSA name mappings for virtual names |
2973 | should be discarded and their symbols rewritten from scratch. When | |
2974 | there is a large number of mappings for virtual names, the | |
2975 | insertion of PHI nodes for the old names in the mappings takes | |
2976 | considerable more time than if we inserted PHI nodes for the | |
2977 | symbols instead. | |
2978 | ||
2979 | Currently the heuristic takes these stats into account: | |
2980 | ||
2981 | - Number of mappings for virtual SSA names. | |
2982 | - Number of distinct virtual symbols involved in those mappings. | |
2983 | ||
2984 | If the number of virtual mappings is much larger than the number of | |
2985 | virtual symbols, then it will be faster to compute PHI insertion | |
2986 | spots for the symbols. Even if this involves traversing the whole | |
2987 | CFG, which is what happens when symbols are renamed from scratch. */ | |
2988 | ||
2989 | static bool | |
2990 | switch_virtuals_to_full_rewrite_p (void) | |
2991 | { | |
2992 | if (update_ssa_stats.num_virtual_mappings < (unsigned) MIN_VIRTUAL_MAPPINGS) | |
2993 | return false; | |
2994 | ||
2995 | if (update_ssa_stats.num_virtual_mappings | |
2996 | > (unsigned) VIRTUAL_MAPPINGS_TO_SYMS_RATIO | |
2997 | * update_ssa_stats.num_virtual_symbols) | |
2998 | return true; | |
2999 | ||
3000 | return false; | |
3001 | } | |
3002 | ||
3003 | ||
3004 | /* Remove every virtual mapping and mark all the affected virtual | |
3005 | symbols for renaming. */ | |
3006 | ||
3007 | static void | |
3008 | switch_virtuals_to_full_rewrite (void) | |
3009 | { | |
dfea6c85 | 3010 | unsigned i = 0; |
b6e7e9af | 3011 | sbitmap_iterator sbi; |
84d65814 DN |
3012 | |
3013 | if (dump_file) | |
3014 | { | |
3015 | fprintf (dump_file, "\nEnabled virtual name mapping heuristic.\n"); | |
3016 | fprintf (dump_file, "\tNumber of virtual mappings: %7u\n", | |
3017 | update_ssa_stats.num_virtual_mappings); | |
3018 | fprintf (dump_file, "\tNumber of unique virtual symbols: %7u\n", | |
3019 | update_ssa_stats.num_virtual_symbols); | |
3020 | fprintf (dump_file, "Updating FUD-chains from top of CFG will be " | |
3021 | "faster than processing\nthe name mappings.\n\n"); | |
3022 | } | |
3023 | ||
3024 | /* Remove all virtual names from NEW_SSA_NAMES and OLD_SSA_NAMES. | |
3025 | Note that it is not really necessary to remove the mappings from | |
3026 | REPL_TBL, that would only waste time. */ | |
b6e7e9af | 3027 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
84d65814 | 3028 | if (!is_gimple_reg (ssa_name (i))) |
b6e7e9af | 3029 | RESET_BIT (new_ssa_names, i); |
84d65814 | 3030 | |
b6e7e9af | 3031 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
84d65814 | 3032 | if (!is_gimple_reg (ssa_name (i))) |
b6e7e9af | 3033 | RESET_BIT (old_ssa_names, i); |
84d65814 | 3034 | |
38635499 | 3035 | mark_set_for_renaming (update_ssa_stats.virtual_symbols); |
84d65814 DN |
3036 | } |
3037 | ||
3038 | ||
0bca51f0 DN |
3039 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of |
3040 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3041 | ||
3042 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3043 | NEW_SSA_NAMES are all re-written to be reached by the | |
3044 | appropriate definition from NEW_SSA_NAMES. | |
3045 | ||
3046 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3047 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3048 | ||
3049 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
3050 | calling register_new_name_mapping for every pair of names that the | |
3051 | caller wants to replace. | |
3052 | ||
3053 | The caller identifies the new names that have been inserted and the | |
3054 | names that need to be replaced by calling register_new_name_mapping | |
3055 | for every pair <NEW, OLD>. Note that the function assumes that the | |
3056 | new names have already been inserted in the IL. | |
3057 | ||
3058 | For instance, given the following code: | |
3059 | ||
3060 | 1 L0: | |
3061 | 2 x_1 = PHI (0, x_5) | |
3062 | 3 if (x_1 < 10) | |
3063 | 4 if (x_1 > 7) | |
3064 | 5 y_2 = 0 | |
3065 | 6 else | |
3066 | 7 y_3 = x_1 + x_7 | |
3067 | 8 endif | |
3068 | 9 x_5 = x_1 + 1 | |
3069 | 10 goto L0; | |
3070 | 11 endif | |
3071 | ||
3072 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3073 | ||
3074 | 1 L0: | |
3075 | 2 x_1 = PHI (0, x_5) | |
3076 | 3 if (x_1 < 10) | |
3077 | 4 x_10 = ... | |
3078 | 5 if (x_1 > 7) | |
3079 | 6 y_2 = 0 | |
3080 | 7 else | |
3081 | 8 x_11 = ... | |
3082 | 9 y_3 = x_1 + x_7 | |
3083 | 10 endif | |
3084 | 11 x_5 = x_1 + 1 | |
3085 | 12 goto L0; | |
3086 | 13 endif | |
3087 | ||
3088 | We want to replace all the uses of x_1 with the new definitions of | |
3089 | x_10 and x_11. Note that the only uses that should be replaced are | |
3090 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3091 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3092 | renaming). | |
3093 | ||
3094 | Additionally, we may need to insert a PHI node at line 11 because | |
3095 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3096 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3097 | nodes is optional. They are not strictly necessary to preserve the | |
3098 | SSA form, and depending on what the caller inserted, they may not | |
3099 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3100 | aspects of how update_ssa operates, see the documentation for | |
3101 | TODO_update_ssa*. */ | |
3102 | ||
3103 | void | |
3104 | update_ssa (unsigned update_flags) | |
3105 | { | |
0bca51f0 DN |
3106 | basic_block bb, start_bb; |
3107 | bitmap_iterator bi; | |
dfea6c85 | 3108 | unsigned i = 0; |
0bca51f0 DN |
3109 | sbitmap tmp; |
3110 | bool insert_phi_p; | |
b6e7e9af | 3111 | sbitmap_iterator sbi; |
0bca51f0 DN |
3112 | |
3113 | if (!need_ssa_update_p ()) | |
3114 | return; | |
3115 | ||
3116 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
3117 | ||
2ce79879 ZD |
3118 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
3119 | if (!phis_to_rewrite) | |
726a989a | 3120 | phis_to_rewrite = VEC_alloc (gimple_vec, heap, last_basic_block); |
95dd3097 | 3121 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3122 | |
0bca51f0 DN |
3123 | /* Ensure that the dominance information is up-to-date. */ |
3124 | calculate_dominance_info (CDI_DOMINATORS); | |
3125 | ||
3126 | /* Only one update flag should be set. */ | |
3127 | gcc_assert (update_flags == TODO_update_ssa | |
3128 | || update_flags == TODO_update_ssa_no_phi | |
3129 | || update_flags == TODO_update_ssa_full_phi | |
3130 | || update_flags == TODO_update_ssa_only_virtuals); | |
3131 | ||
3132 | /* If we only need to update virtuals, remove all the mappings for | |
84d65814 DN |
3133 | real names before proceeding. The caller is responsible for |
3134 | having dealt with the name mappings before calling update_ssa. */ | |
0bca51f0 DN |
3135 | if (update_flags == TODO_update_ssa_only_virtuals) |
3136 | { | |
3137 | sbitmap_zero (old_ssa_names); | |
3138 | sbitmap_zero (new_ssa_names); | |
3139 | htab_empty (repl_tbl); | |
0bca51f0 DN |
3140 | } |
3141 | ||
84d65814 | 3142 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 DN |
3143 | |
3144 | if (insert_phi_p) | |
3145 | { | |
9caf90a8 KH |
3146 | /* If the caller requested PHI nodes to be added, initialize |
3147 | live-in information data structures (DEF_BLOCKS). */ | |
0bca51f0 DN |
3148 | |
3149 | /* For each SSA name N, the DEF_BLOCKS table describes where the | |
3150 | name is defined, which blocks have PHI nodes for N, and which | |
3151 | blocks have uses of N (i.e., N is live-on-entry in those | |
3152 | blocks). */ | |
3153 | def_blocks = htab_create (num_ssa_names, def_blocks_hash, | |
3154 | def_blocks_eq, def_blocks_free); | |
3155 | } | |
3156 | else | |
3157 | { | |
0bca51f0 DN |
3158 | def_blocks = NULL; |
3159 | } | |
3160 | ||
84d65814 DN |
3161 | /* Heuristic to avoid massive slow downs when the replacement |
3162 | mappings include lots of virtual names. */ | |
3163 | if (insert_phi_p && switch_virtuals_to_full_rewrite_p ()) | |
3164 | switch_virtuals_to_full_rewrite (); | |
3165 | ||
38635499 DN |
3166 | /* If there are symbols to rename, identify those symbols that are |
3167 | GIMPLE registers into the set REGS_TO_RENAME and those that are | |
3168 | memory symbols into the set MEM_SYMS_TO_RENAME. */ | |
3169 | if (!bitmap_empty_p (syms_to_rename)) | |
3170 | { | |
3b302421 RG |
3171 | unsigned i; |
3172 | bitmap_iterator bi; | |
38635499 | 3173 | |
3b302421 | 3174 | EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi) |
38635499 | 3175 | { |
3b302421 | 3176 | tree sym = referenced_var (i); |
38635499 DN |
3177 | if (is_gimple_reg (sym)) |
3178 | bitmap_set_bit (regs_to_rename, i); | |
3179 | else | |
3180 | { | |
3181 | /* Memory partitioning information may have been | |
3182 | computed after the symbol was marked for renaming, | |
3183 | if SYM is inside a partition also mark the partition | |
3184 | for renaming. */ | |
3185 | tree mpt = memory_partition (sym); | |
3186 | if (mpt) | |
3187 | bitmap_set_bit (syms_to_rename, DECL_UID (mpt)); | |
3188 | } | |
3189 | } | |
3190 | ||
3191 | /* Memory symbols are those not in REGS_TO_RENAME. */ | |
3192 | bitmap_and_compl (mem_syms_to_rename, syms_to_rename, regs_to_rename); | |
3193 | } | |
3194 | ||
84d65814 DN |
3195 | /* If there are names defined in the replacement table, prepare |
3196 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3197 | OLD_SSA_NAMES. */ | |
3198 | if (sbitmap_first_set_bit (new_ssa_names) >= 0) | |
3199 | { | |
95dd3097 | 3200 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3201 | |
3202 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3203 | removal, and there are no symbols to rename, then there's | |
3204 | nothing else to do. */ | |
3205 | if (sbitmap_first_set_bit (new_ssa_names) < 0 | |
3206 | && bitmap_empty_p (syms_to_rename)) | |
3207 | goto done; | |
3208 | } | |
3209 | ||
3210 | /* Next, determine the block at which to start the renaming process. */ | |
3211 | if (!bitmap_empty_p (syms_to_rename)) | |
3212 | { | |
3213 | /* If we have to rename some symbols from scratch, we need to | |
3214 | start the process at the root of the CFG. FIXME, it should | |
3215 | be possible to determine the nearest block that had a | |
3216 | definition for each of the symbols that are marked for | |
3217 | updating. For now this seems more work than it's worth. */ | |
3218 | start_bb = ENTRY_BLOCK_PTR; | |
3219 | ||
38635499 DN |
3220 | /* Traverse the CFG looking for existing definitions and uses of |
3221 | symbols in SYMS_TO_RENAME. Mark interesting blocks and | |
3222 | statements and set local live-in information for the PHI | |
3223 | placement heuristics. */ | |
95dd3097 | 3224 | prepare_block_for_update (start_bb, insert_phi_p); |
0bca51f0 DN |
3225 | } |
3226 | else | |
84d65814 DN |
3227 | { |
3228 | /* Otherwise, the entry block to the region is the nearest | |
3229 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3230 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3231 | blocks_to_update); | |
84d65814 | 3232 | } |
0bca51f0 DN |
3233 | |
3234 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3235 | of every block, creating new definitions for names in OLD_SSA_NAMES |
0bca51f0 DN |
3236 | and for symbols in SYMS_TO_RENAME. */ |
3237 | if (insert_phi_p) | |
3238 | { | |
9caf90a8 KH |
3239 | bitmap *dfs; |
3240 | ||
3241 | /* If the caller requested PHI nodes to be added, compute | |
3242 | dominance frontiers. */ | |
858904db | 3243 | dfs = XNEWVEC (bitmap, last_basic_block); |
9caf90a8 KH |
3244 | FOR_EACH_BB (bb) |
3245 | dfs[bb->index] = BITMAP_ALLOC (NULL); | |
3246 | compute_dominance_frontiers (dfs); | |
3247 | ||
0bca51f0 DN |
3248 | if (sbitmap_first_set_bit (old_ssa_names) >= 0) |
3249 | { | |
b6e7e9af KH |
3250 | sbitmap_iterator sbi; |
3251 | ||
84d65814 DN |
3252 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3253 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3254 | will grow while we are traversing it (but it will not | |
3255 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3256 | for traversal. */ | |
0bca51f0 DN |
3257 | sbitmap tmp = sbitmap_alloc (old_ssa_names->n_bits); |
3258 | sbitmap_copy (tmp, old_ssa_names); | |
b6e7e9af | 3259 | EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i, sbi) |
95dd3097 | 3260 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3261 | update_flags); |
0bca51f0 DN |
3262 | sbitmap_free (tmp); |
3263 | } | |
3264 | ||
3265 | EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi) | |
38635499 DN |
3266 | insert_updated_phi_nodes_for (referenced_var (i), dfs, blocks_to_update, |
3267 | update_flags); | |
0bca51f0 | 3268 | |
9caf90a8 KH |
3269 | FOR_EACH_BB (bb) |
3270 | BITMAP_FREE (dfs[bb->index]); | |
3271 | free (dfs); | |
3272 | ||
0bca51f0 DN |
3273 | /* Insertion of PHI nodes may have added blocks to the region. |
3274 | We need to re-compute START_BB to include the newly added | |
3275 | blocks. */ | |
3276 | if (start_bb != ENTRY_BLOCK_PTR) | |
95dd3097 ZD |
3277 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3278 | blocks_to_update); | |
0bca51f0 DN |
3279 | } |
3280 | ||
3281 | /* Reset the current definition for name and symbol before renaming | |
3282 | the sub-graph. */ | |
b6e7e9af KH |
3283 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
3284 | set_current_def (ssa_name (i), NULL_TREE); | |
0bca51f0 DN |
3285 | |
3286 | EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi) | |
3287 | set_current_def (referenced_var (i), NULL_TREE); | |
3288 | ||
3289 | /* Now start the renaming process at START_BB. */ | |
3290 | tmp = sbitmap_alloc (last_basic_block); | |
3291 | sbitmap_zero (tmp); | |
95dd3097 | 3292 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3293 | SET_BIT (tmp, i); |
3294 | ||
3295 | rewrite_blocks (start_bb, REWRITE_UPDATE, tmp); | |
3296 | ||
3297 | sbitmap_free (tmp); | |
3298 | ||
3299 | /* Debugging dumps. */ | |
3300 | if (dump_file) | |
3301 | { | |
3302 | int c; | |
3303 | unsigned i; | |
3304 | ||
84d65814 | 3305 | dump_update_ssa (dump_file); |
0bca51f0 DN |
3306 | |
3307 | fprintf (dump_file, "Incremental SSA update started at block: %d\n\n", | |
3308 | start_bb->index); | |
3309 | ||
3310 | c = 0; | |
95dd3097 | 3311 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3312 | c++; |
3313 | fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block); | |
3314 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n\n", | |
3315 | c, PERCENT (c, last_basic_block)); | |
3316 | ||
3317 | if (dump_flags & TDF_DETAILS) | |
3318 | { | |
3319 | fprintf (dump_file, "Affected blocks: "); | |
95dd3097 | 3320 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3321 | fprintf (dump_file, "%u ", i); |
3322 | fprintf (dump_file, "\n"); | |
3323 | } | |
3324 | ||
3325 | fprintf (dump_file, "\n\n"); | |
3326 | } | |
3327 | ||
3328 | /* Free allocated memory. */ | |
84d65814 | 3329 | done: |
0bca51f0 DN |
3330 | delete_update_ssa (); |
3331 | ||
3332 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3333 | } |