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6de9cd9a | 1 | /* Rewrite a program in Normal form into SSA. |
a5544970 | 2 | Copyright (C) 2001-2019 Free Software Foundation, Inc. |
6de9cd9a DN |
3 | Contributed by Diego Novillo <dnovillo@redhat.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9dcd6f09 | 9 | the Free Software Foundation; either version 3, or (at your option) |
6de9cd9a DN |
10 | any later version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
c7131fb2 | 24 | #include "backend.h" |
957060b5 | 25 | #include "rtl.h" |
6de9cd9a | 26 | #include "tree.h" |
c7131fb2 | 27 | #include "gimple.h" |
957060b5 | 28 | #include "tree-pass.h" |
c7131fb2 | 29 | #include "ssa.h" |
957060b5 AM |
30 | #include "gimple-pretty-print.h" |
31 | #include "diagnostic-core.h" | |
6de9cd9a | 32 | #include "langhooks.h" |
60393bbc | 33 | #include "cfganal.h" |
5be5c238 | 34 | #include "gimple-iterator.h" |
442b4905 | 35 | #include "tree-cfg.h" |
442b4905 AM |
36 | #include "tree-into-ssa.h" |
37 | #include "tree-dfa.h" | |
38 | #include "tree-ssa.h" | |
6de9cd9a | 39 | #include "domwalk.h" |
f0251020 | 40 | #include "statistics.h" |
314e6352 ML |
41 | #include "stringpool.h" |
42 | #include "attribs.h" | |
f6b9f2ff | 43 | #include "asan.h" |
6de9cd9a | 44 | |
1fe37220 | 45 | #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y)) |
726a989a | 46 | |
6de9cd9a DN |
47 | /* This file builds the SSA form for a function as described in: |
48 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
49 | Computing Static Single Assignment Form and the Control Dependence | |
50 | Graph. ACM Transactions on Programming Languages and Systems, | |
51 | 13(4):451-490, October 1991. */ | |
52 | ||
6de9cd9a DN |
53 | /* Structure to map a variable VAR to the set of blocks that contain |
54 | definitions for VAR. */ | |
526ceb68 | 55 | struct def_blocks |
6de9cd9a | 56 | { |
6de9cd9a DN |
57 | /* Blocks that contain definitions of VAR. Bit I will be set if the |
58 | Ith block contains a definition of VAR. */ | |
59 | bitmap def_blocks; | |
60 | ||
7256233c | 61 | /* Blocks that contain a PHI node for VAR. */ |
5f240ec4 ZD |
62 | bitmap phi_blocks; |
63 | ||
6de9cd9a DN |
64 | /* Blocks where VAR is live-on-entry. Similar semantics as |
65 | DEF_BLOCKS. */ | |
66 | bitmap livein_blocks; | |
67 | }; | |
68 | ||
9fae925b | 69 | /* Stack of trees used to restore the global currdefs to its original |
0bca51f0 DN |
70 | state after completing rewriting of a block and its dominator |
71 | children. Its elements have the following properties: | |
9fae925b | 72 | |
38635499 DN |
73 | - An SSA_NAME (N) indicates that the current definition of the |
74 | underlying variable should be set to the given SSA_NAME. If the | |
75 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
76 | next slot in the stack must be a _DECL node (SYM). In this case, | |
77 | the name N in the previous slot is the current reaching | |
78 | definition for SYM. | |
9fae925b | 79 | |
0bca51f0 DN |
80 | - A _DECL node indicates that the underlying variable has no |
81 | current definition. | |
7256233c | 82 | |
38635499 | 83 | - A NULL node at the top entry is used to mark the last slot |
0bca51f0 | 84 | associated with the current block. */ |
9771b263 | 85 | static vec<tree> block_defs_stack; |
3a2e4b46 | 86 | |
726a989a | 87 | |
0bca51f0 DN |
88 | /* Set of existing SSA names being replaced by update_ssa. */ |
89 | static sbitmap old_ssa_names; | |
90 | ||
91 | /* Set of new SSA names being added by update_ssa. Note that both | |
92 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
93 | the operations done on them are presence tests. */ | |
94 | static sbitmap new_ssa_names; | |
95 | ||
16876bdc | 96 | static sbitmap interesting_blocks; |
726a989a | 97 | |
0bca51f0 DN |
98 | /* Set of SSA names that have been marked to be released after they |
99 | were registered in the replacement table. They will be finally | |
100 | released after we finish updating the SSA web. */ | |
d2e2feaa | 101 | bitmap names_to_release; |
0bca51f0 | 102 | |
9771b263 | 103 | /* vec of vec of PHIs to rewrite in a basic block. Element I corresponds |
580b2c2e SB |
104 | the to basic block with index I. Allocated once per compilation, *not* |
105 | released between different functions. */ | |
538dd0b7 | 106 | static vec< vec<gphi *> > phis_to_rewrite; |
2ce79879 ZD |
107 | |
108 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
109 | static bitmap blocks_with_phis_to_rewrite; |
110 | ||
0bca51f0 | 111 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
45db3141 RG |
112 | to grow as the callers to create_new_def_for will create new names on |
113 | the fly. | |
114 | FIXME. Currently set to 1/3 to avoid frequent reallocations but still | |
115 | need to find a reasonable growth strategy. */ | |
0bca51f0 DN |
116 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) |
117 | ||
0bca51f0 | 118 | |
5006671f | 119 | /* The function the SSA updating data structures have been initialized for. |
45db3141 | 120 | NULL if they need to be initialized by create_new_def_for. */ |
5006671f | 121 | static struct function *update_ssa_initialized_fn = NULL; |
0bca51f0 | 122 | |
6de9cd9a DN |
123 | /* Global data to attach to the main dominator walk structure. */ |
124 | struct mark_def_sites_global_data | |
125 | { | |
0bca51f0 DN |
126 | /* This bitmap contains the variables which are set before they |
127 | are used in a basic block. */ | |
7d793e36 | 128 | bitmap kills; |
6de9cd9a DN |
129 | }; |
130 | ||
80560f95 AM |
131 | /* It is advantageous to avoid things like life analysis for variables which |
132 | do not need PHI nodes. This enum describes whether or not a particular | |
133 | variable may need a PHI node. */ | |
134 | ||
135 | enum need_phi_state { | |
136 | /* This is the default. If we are still in this state after finding | |
137 | all the definition and use sites, then we will assume the variable | |
138 | needs PHI nodes. This is probably an overly conservative assumption. */ | |
139 | NEED_PHI_STATE_UNKNOWN, | |
140 | ||
141 | /* This state indicates that we have seen one or more sets of the | |
142 | variable in a single basic block and that the sets dominate all | |
143 | uses seen so far. If after finding all definition and use sites | |
144 | we are still in this state, then the variable does not need any | |
145 | PHI nodes. */ | |
146 | NEED_PHI_STATE_NO, | |
147 | ||
148 | /* This state indicates that we have either seen multiple definitions of | |
149 | the variable in multiple blocks, or that we encountered a use in a | |
150 | block that was not dominated by the block containing the set(s) of | |
151 | this variable. This variable is assumed to need PHI nodes. */ | |
152 | NEED_PHI_STATE_MAYBE | |
153 | }; | |
154 | ||
8812aab1 | 155 | /* Information stored for both SSA names and decls. */ |
526ceb68 | 156 | struct common_info |
b4e209fd | 157 | { |
b4e209fd RG |
158 | /* This field indicates whether or not the variable may need PHI nodes. |
159 | See the enum's definition for more detailed information about the | |
160 | states. */ | |
161 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
162 | ||
8812aab1 | 163 | /* The current reaching definition replacing this var. */ |
b4e209fd RG |
164 | tree current_def; |
165 | ||
8812aab1 | 166 | /* Definitions for this var. */ |
526ceb68 | 167 | struct def_blocks def_blocks; |
b4e209fd RG |
168 | }; |
169 | ||
8812aab1 | 170 | /* Information stored for decls. */ |
526ceb68 | 171 | struct var_info |
8812aab1 RG |
172 | { |
173 | /* The variable. */ | |
174 | tree var; | |
175 | ||
176 | /* Information stored for both SSA names and decls. */ | |
526ceb68 | 177 | common_info info; |
8812aab1 RG |
178 | }; |
179 | ||
b4e209fd | 180 | |
bf190e8d LC |
181 | /* VAR_INFOS hashtable helpers. */ |
182 | ||
526ceb68 | 183 | struct var_info_hasher : free_ptr_hash <var_info> |
bf190e8d | 184 | { |
84baa4b9 TS |
185 | static inline hashval_t hash (const value_type &); |
186 | static inline bool equal (const value_type &, const compare_type &); | |
bf190e8d LC |
187 | }; |
188 | ||
189 | inline hashval_t | |
84baa4b9 | 190 | var_info_hasher::hash (const value_type &p) |
bf190e8d LC |
191 | { |
192 | return DECL_UID (p->var); | |
193 | } | |
194 | ||
195 | inline bool | |
84baa4b9 | 196 | var_info_hasher::equal (const value_type &p1, const compare_type &p2) |
bf190e8d LC |
197 | { |
198 | return p1->var == p2->var; | |
199 | } | |
200 | ||
201 | ||
b4e209fd RG |
202 | /* Each entry in VAR_INFOS contains an element of type STRUCT |
203 | VAR_INFO_D. */ | |
c203e8a7 | 204 | static hash_table<var_info_hasher> *var_infos; |
b4e209fd RG |
205 | |
206 | ||
0bca51f0 | 207 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
208 | struct ssa_name_info |
209 | { | |
891f2df6 RG |
210 | /* Age of this record (so that info_for_ssa_name table can be cleared |
211 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
212 | are assumed to be null. */ | |
213 | unsigned age; | |
95dd3097 | 214 | |
891f2df6 RG |
215 | /* Replacement mappings, allocated from update_ssa_obstack. */ |
216 | bitmap repl_set; | |
b4e209fd | 217 | |
8812aab1 | 218 | /* Information stored for both SSA names and decls. */ |
526ceb68 | 219 | common_info info; |
5f240ec4 | 220 | }; |
6de9cd9a | 221 | |
526ceb68 | 222 | static vec<ssa_name_info *> info_for_ssa_name; |
95dd3097 ZD |
223 | static unsigned current_info_for_ssa_name_age; |
224 | ||
891f2df6 RG |
225 | static bitmap_obstack update_ssa_obstack; |
226 | ||
95dd3097 | 227 | /* The set of blocks affected by update_ssa. */ |
95dd3097 | 228 | static bitmap blocks_to_update; |
6de9cd9a | 229 | |
0bca51f0 DN |
230 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
231 | called several times to do different, but related, tasks. | |
232 | Initially, we need it to rename the whole program into SSA form. | |
233 | At other times, we may need it to only rename into SSA newly | |
234 | exposed symbols. Finally, we can also call it to incrementally fix | |
235 | an already built SSA web. */ | |
236 | enum rewrite_mode { | |
237 | /* Convert the whole function into SSA form. */ | |
238 | REWRITE_ALL, | |
239 | ||
240 | /* Incrementally update the SSA web by replacing existing SSA | |
241 | names with new ones. See update_ssa for details. */ | |
242 | REWRITE_UPDATE | |
243 | }; | |
244 | ||
13714310 RG |
245 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ |
246 | static bitmap symbols_to_rename_set; | |
9771b263 | 247 | static vec<tree> symbols_to_rename; |
13714310 RG |
248 | |
249 | /* Mark SYM for renaming. */ | |
250 | ||
251 | static void | |
252 | mark_for_renaming (tree sym) | |
253 | { | |
254 | if (!symbols_to_rename_set) | |
255 | symbols_to_rename_set = BITMAP_ALLOC (NULL); | |
256 | if (bitmap_set_bit (symbols_to_rename_set, DECL_UID (sym))) | |
9771b263 | 257 | symbols_to_rename.safe_push (sym); |
13714310 RG |
258 | } |
259 | ||
260 | /* Return true if SYM is marked for renaming. */ | |
261 | ||
262 | static bool | |
263 | marked_for_renaming (tree sym) | |
264 | { | |
70b5e7dc | 265 | if (!symbols_to_rename_set || sym == NULL_TREE) |
13714310 RG |
266 | return false; |
267 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
268 | } | |
269 | ||
270 | ||
726a989a RB |
271 | /* Return true if STMT needs to be rewritten. When renaming a subset |
272 | of the variables, not all statements will be processed. This is | |
273 | decided in mark_def_sites. */ | |
274 | ||
275 | static inline bool | |
355fe088 | 276 | rewrite_uses_p (gimple *stmt) |
726a989a RB |
277 | { |
278 | return gimple_visited_p (stmt); | |
279 | } | |
280 | ||
281 | ||
282 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
283 | ||
284 | static inline void | |
355fe088 | 285 | set_rewrite_uses (gimple *stmt, bool rewrite_p) |
726a989a RB |
286 | { |
287 | gimple_set_visited (stmt, rewrite_p); | |
288 | } | |
289 | ||
290 | ||
291 | /* Return true if the DEFs created by statement STMT should be | |
292 | registered when marking new definition sites. This is slightly | |
293 | different than rewrite_uses_p: it's used by update_ssa to | |
294 | distinguish statements that need to have both uses and defs | |
295 | processed from those that only need to have their defs processed. | |
296 | Statements that define new SSA names only need to have their defs | |
297 | registered, but they don't need to have their uses renamed. */ | |
298 | ||
299 | static inline bool | |
355fe088 | 300 | register_defs_p (gimple *stmt) |
726a989a RB |
301 | { |
302 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
303 | } | |
304 | ||
305 | ||
306 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
307 | ||
308 | static inline void | |
355fe088 | 309 | set_register_defs (gimple *stmt, bool register_defs_p) |
726a989a RB |
310 | { |
311 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
312 | } | |
313 | ||
314 | ||
5f240ec4 ZD |
315 | /* Get the information associated with NAME. */ |
316 | ||
526ceb68 | 317 | static inline ssa_name_info * |
5f240ec4 ZD |
318 | get_ssa_name_ann (tree name) |
319 | { | |
95dd3097 | 320 | unsigned ver = SSA_NAME_VERSION (name); |
9771b263 | 321 | unsigned len = info_for_ssa_name.length (); |
95dd3097 ZD |
322 | struct ssa_name_info *info; |
323 | ||
f5843d08 | 324 | /* Re-allocate the vector at most once per update/into-SSA. */ |
95dd3097 | 325 | if (ver >= len) |
9771b263 | 326 | info_for_ssa_name.safe_grow_cleared (num_ssa_names); |
f5843d08 RG |
327 | |
328 | /* But allocate infos lazily. */ | |
9771b263 | 329 | info = info_for_ssa_name[ver]; |
f5843d08 | 330 | if (!info) |
95dd3097 | 331 | { |
f5843d08 RG |
332 | info = XCNEW (struct ssa_name_info); |
333 | info->age = current_info_for_ssa_name_age; | |
334 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
9771b263 | 335 | info_for_ssa_name[ver] = info; |
95dd3097 ZD |
336 | } |
337 | ||
95dd3097 ZD |
338 | if (info->age < current_info_for_ssa_name_age) |
339 | { | |
95dd3097 | 340 | info->age = current_info_for_ssa_name_age; |
8812aab1 RG |
341 | info->repl_set = NULL; |
342 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
343 | info->info.current_def = NULL_TREE; | |
344 | info->info.def_blocks.def_blocks = NULL; | |
345 | info->info.def_blocks.phi_blocks = NULL; | |
346 | info->info.def_blocks.livein_blocks = NULL; | |
95dd3097 | 347 | } |
5f240ec4 | 348 | |
95dd3097 | 349 | return info; |
5f240ec4 ZD |
350 | } |
351 | ||
b4e209fd RG |
352 | /* Return and allocate the auxiliar information for DECL. */ |
353 | ||
526ceb68 | 354 | static inline var_info * |
b4e209fd RG |
355 | get_var_info (tree decl) |
356 | { | |
526ceb68 TS |
357 | var_info vi; |
358 | var_info **slot; | |
b4e209fd | 359 | vi.var = decl; |
c203e8a7 | 360 | slot = var_infos->find_slot_with_hash (&vi, DECL_UID (decl), INSERT); |
b4e209fd RG |
361 | if (*slot == NULL) |
362 | { | |
526ceb68 | 363 | var_info *v = XCNEW (var_info); |
b4e209fd | 364 | v->var = decl; |
bf190e8d | 365 | *slot = v; |
b4e209fd RG |
366 | return v; |
367 | } | |
bf190e8d | 368 | return *slot; |
b4e209fd RG |
369 | } |
370 | ||
38635499 DN |
371 | |
372 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
373 | |
374 | static void | |
375 | clear_ssa_name_info (void) | |
376 | { | |
377 | current_info_for_ssa_name_age++; | |
891f2df6 RG |
378 | |
379 | /* If current_info_for_ssa_name_age wraps we use stale information. | |
380 | Asser that this does not happen. */ | |
381 | gcc_assert (current_info_for_ssa_name_age != 0); | |
95dd3097 | 382 | } |
7256233c | 383 | |
38635499 | 384 | |
8812aab1 | 385 | /* Get access to the auxiliar information stored per SSA name or decl. */ |
5f240ec4 | 386 | |
526ceb68 | 387 | static inline common_info * |
8812aab1 | 388 | get_common_info (tree var) |
5f240ec4 ZD |
389 | { |
390 | if (TREE_CODE (var) == SSA_NAME) | |
8812aab1 | 391 | return &get_ssa_name_ann (var)->info; |
5f240ec4 | 392 | else |
8812aab1 | 393 | return &get_var_info (var)->info; |
5f240ec4 ZD |
394 | } |
395 | ||
7256233c | 396 | |
5f240ec4 ZD |
397 | /* Return the current definition for VAR. */ |
398 | ||
84d65814 | 399 | tree |
5f240ec4 ZD |
400 | get_current_def (tree var) |
401 | { | |
8812aab1 | 402 | return get_common_info (var)->current_def; |
5f240ec4 ZD |
403 | } |
404 | ||
7256233c | 405 | |
5f240ec4 ZD |
406 | /* Sets current definition of VAR to DEF. */ |
407 | ||
84d65814 | 408 | void |
5f240ec4 ZD |
409 | set_current_def (tree var, tree def) |
410 | { | |
8812aab1 | 411 | get_common_info (var)->current_def = def; |
5f240ec4 ZD |
412 | } |
413 | ||
95dd3097 ZD |
414 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
415 | all statements in basic block BB. */ | |
416 | ||
417 | static void | |
418 | initialize_flags_in_bb (basic_block bb) | |
419 | { | |
355fe088 | 420 | gimple *stmt; |
726a989a | 421 | gimple_stmt_iterator gsi; |
95dd3097 | 422 | |
726a989a | 423 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 424 | { |
355fe088 | 425 | gimple *phi = gsi_stmt (gsi); |
726a989a RB |
426 | set_rewrite_uses (phi, false); |
427 | set_register_defs (phi, false); | |
95dd3097 ZD |
428 | } |
429 | ||
726a989a | 430 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 431 | { |
726a989a RB |
432 | stmt = gsi_stmt (gsi); |
433 | ||
95dd3097 ZD |
434 | /* We are going to use the operand cache API, such as |
435 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
436 | cache for each statement should be up-to-date. */ | |
4ad14919 | 437 | gcc_checking_assert (!gimple_modified_p (stmt)); |
726a989a RB |
438 | set_rewrite_uses (stmt, false); |
439 | set_register_defs (stmt, false); | |
95dd3097 ZD |
440 | } |
441 | } | |
442 | ||
443 | /* Mark block BB as interesting for update_ssa. */ | |
444 | ||
445 | static void | |
446 | mark_block_for_update (basic_block bb) | |
447 | { | |
4ad14919 | 448 | gcc_checking_assert (blocks_to_update != NULL); |
f3cf730b | 449 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
95dd3097 | 450 | return; |
95dd3097 ZD |
451 | initialize_flags_in_bb (bb); |
452 | } | |
453 | ||
7256233c DN |
454 | /* Return the set of blocks where variable VAR is defined and the blocks |
455 | where VAR is live on entry (livein). If no entry is found in | |
456 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 457 | |
526ceb68 TS |
458 | static inline def_blocks * |
459 | get_def_blocks_for (common_info *info) | |
6de9cd9a | 460 | { |
526ceb68 | 461 | def_blocks *db_p = &info->def_blocks; |
b4e209fd | 462 | if (!db_p->def_blocks) |
6de9cd9a | 463 | { |
b4e209fd RG |
464 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
465 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
466 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
a32b97a2 BB |
467 | } |
468 | ||
7256233c | 469 | return db_p; |
6de9cd9a DN |
470 | } |
471 | ||
7d5f9cc6 | 472 | |
5f240ec4 | 473 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 474 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
475 | |
476 | static void | |
0bca51f0 | 477 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a | 478 | { |
526ceb68 TS |
479 | def_blocks *db_p; |
480 | common_info *info; | |
34eb8991 | 481 | |
8812aab1 RG |
482 | info = get_common_info (var); |
483 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
484 | |
485 | /* Set the bit corresponding to the block where VAR is defined. */ | |
486 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
487 | if (phi_p) |
488 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 489 | |
7256233c | 490 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
491 | |
492 | If we are in the UNKNOWN state, then this is the first definition | |
493 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 494 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
495 | transition to NEED_PHI_STATE_NO). |
496 | ||
497 | If we are in any other state, then we either have multiple definitions | |
498 | of this variable occurring in different blocks or we saw a use of the | |
499 | variable which was not dominated by the block containing the | |
500 | definition(s). In this case we may need a PHI node, so enter | |
501 | state NEED_PHI_STATE_MAYBE. */ | |
8812aab1 RG |
502 | if (info->need_phi_state == NEED_PHI_STATE_UNKNOWN) |
503 | info->need_phi_state = NEED_PHI_STATE_NO; | |
6de9cd9a | 504 | else |
8812aab1 | 505 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
506 | } |
507 | ||
508 | ||
509 | /* Mark block BB as having VAR live at the entry to BB. */ | |
510 | ||
511 | static void | |
512 | set_livein_block (tree var, basic_block bb) | |
513 | { | |
526ceb68 TS |
514 | common_info *info; |
515 | def_blocks *db_p; | |
6de9cd9a | 516 | |
8812aab1 RG |
517 | info = get_common_info (var); |
518 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
519 | |
520 | /* Set the bit corresponding to the block where VAR is live in. */ | |
521 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
522 | ||
7256233c | 523 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
524 | |
525 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
526 | by the single block containing the definition(s) of this variable. If | |
527 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
528 | NEED_PHI_STATE_MAYBE. */ | |
8812aab1 | 529 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
6de9cd9a DN |
530 | { |
531 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
532 | ||
533 | if (def_block_index == -1 | |
534 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
06e28de2 | 535 | BASIC_BLOCK_FOR_FN (cfun, def_block_index))) |
8812aab1 | 536 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
537 | } |
538 | else | |
8812aab1 | 539 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
540 | } |
541 | ||
542 | ||
0bca51f0 | 543 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
6de9cd9a | 544 | |
0bca51f0 DN |
545 | static inline bool |
546 | is_old_name (tree name) | |
547 | { | |
84d65814 | 548 | unsigned ver = SSA_NAME_VERSION (name); |
c36eadbe | 549 | if (!old_ssa_names) |
5006671f | 550 | return false; |
c36eadbe | 551 | return (ver < SBITMAP_SIZE (old_ssa_names) |
d7c028c0 | 552 | && bitmap_bit_p (old_ssa_names, ver)); |
0bca51f0 DN |
553 | } |
554 | ||
555 | ||
556 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 557 | |
0bca51f0 DN |
558 | static inline bool |
559 | is_new_name (tree name) | |
560 | { | |
84d65814 | 561 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
562 | if (!new_ssa_names) |
563 | return false; | |
5829cc0f | 564 | return (ver < SBITMAP_SIZE (new_ssa_names) |
d7c028c0 | 565 | && bitmap_bit_p (new_ssa_names, ver)); |
6de9cd9a DN |
566 | } |
567 | ||
7256233c | 568 | |
82d6e6fc | 569 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
570 | |
571 | static inline bitmap | |
82d6e6fc | 572 | names_replaced_by (tree new_tree) |
0bca51f0 | 573 | { |
891f2df6 | 574 | return get_ssa_name_ann (new_tree)->repl_set; |
0bca51f0 DN |
575 | } |
576 | ||
577 | ||
82d6e6fc | 578 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
579 | |
580 | static inline void | |
82d6e6fc | 581 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 | 582 | { |
891f2df6 RG |
583 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
584 | if (!*set) | |
585 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
586 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
0bca51f0 DN |
587 | } |
588 | ||
589 | ||
82d6e6fc | 590 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
591 | represents the set of names O_1 ... O_j replaced by N_i. This is |
592 | used by update_ssa and its helpers to introduce new SSA names in an | |
593 | already formed SSA web. */ | |
594 | ||
595 | static void | |
82d6e6fc | 596 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 | 597 | { |
82d6e6fc | 598 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
4ad14919 RG |
599 | gcc_checking_assert (new_tree != old |
600 | && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 601 | |
38635499 DN |
602 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
603 | caller may have created new names since the set was created. */ | |
5829cc0f | 604 | if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1) |
38635499 DN |
605 | { |
606 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
607 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
608 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
609 | } |
610 | ||
0bca51f0 | 611 | /* Update the REPL_TBL table. */ |
82d6e6fc | 612 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 613 | |
0bca51f0 | 614 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 615 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 616 | if (is_new_name (old)) |
82d6e6fc | 617 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 618 | |
82d6e6fc | 619 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 620 | respectively. */ |
d7c028c0 LC |
621 | bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
622 | bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old)); | |
d00ad49b | 623 | } |
6de9cd9a | 624 | |
6de9cd9a | 625 | |
7256233c DN |
626 | /* Call back for walk_dominator_tree used to collect definition sites |
627 | for every variable in the function. For every statement S in block | |
628 | BB: | |
6de9cd9a | 629 | |
f47c96aa | 630 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
ccf5c864 | 631 | KILLS. |
6de9cd9a | 632 | |
7256233c | 633 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 634 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 635 | |
7256233c DN |
636 | This information is used to determine which variables are live |
637 | across block boundaries to reduce the number of PHI nodes | |
638 | we create. */ | |
6de9cd9a | 639 | |
7256233c | 640 | static void |
355fe088 | 641 | mark_def_sites (basic_block bb, gimple *stmt, bitmap kills) |
7256233c | 642 | { |
726a989a | 643 | tree def; |
7256233c | 644 | use_operand_p use_p; |
7256233c DN |
645 | ssa_op_iter iter; |
646 | ||
726a989a RB |
647 | /* Since this is the first time that we rewrite the program into SSA |
648 | form, force an operand scan on every statement. */ | |
726a989a | 649 | update_stmt (stmt); |
7256233c | 650 | |
4ad14919 | 651 | gcc_checking_assert (blocks_to_update == NULL); |
726a989a RB |
652 | set_register_defs (stmt, false); |
653 | set_rewrite_uses (stmt, false); | |
7256233c | 654 | |
b5b8b0ac | 655 | if (is_gimple_debug (stmt)) |
ddb555ed JJ |
656 | { |
657 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
658 | { | |
659 | tree sym = USE_FROM_PTR (use_p); | |
4ad14919 | 660 | gcc_checking_assert (DECL_P (sym)); |
ddb555ed JJ |
661 | set_rewrite_uses (stmt, true); |
662 | } | |
663 | if (rewrite_uses_p (stmt)) | |
d7c028c0 | 664 | bitmap_set_bit (interesting_blocks, bb->index); |
ddb555ed JJ |
665 | return; |
666 | } | |
b5b8b0ac | 667 | |
7256233c DN |
668 | /* If a variable is used before being set, then the variable is live |
669 | across a block boundary, so mark it live-on-entry to BB. */ | |
39c58b3a | 670 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
7256233c | 671 | { |
0bca51f0 | 672 | tree sym = USE_FROM_PTR (use_p); |
381cdae4 RB |
673 | if (TREE_CODE (sym) == SSA_NAME) |
674 | continue; | |
4ad14919 | 675 | gcc_checking_assert (DECL_P (sym)); |
a3648cfc | 676 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 677 | set_livein_block (sym, bb); |
726a989a | 678 | set_rewrite_uses (stmt, true); |
7256233c | 679 | } |
b8698a0f | 680 | |
38635499 DN |
681 | /* Now process the defs. Mark BB as the definition block and add |
682 | each def to the set of killed symbols. */ | |
39c58b3a | 683 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
7256233c | 684 | { |
381cdae4 RB |
685 | if (TREE_CODE (def) == SSA_NAME) |
686 | continue; | |
4ad14919 | 687 | gcc_checking_assert (DECL_P (def)); |
0bca51f0 | 688 | set_def_block (def, bb, false); |
a3648cfc | 689 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 690 | set_register_defs (stmt, true); |
7256233c | 691 | } |
0bca51f0 DN |
692 | |
693 | /* If we found the statement interesting then also mark the block BB | |
694 | as interesting. */ | |
726a989a | 695 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
d7c028c0 | 696 | bitmap_set_bit (interesting_blocks, bb->index); |
7256233c DN |
697 | } |
698 | ||
f074ff6c ZD |
699 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
700 | in the dfs numbering of the dominance tree. */ | |
701 | ||
702 | struct dom_dfsnum | |
703 | { | |
704 | /* Basic block whose index this entry corresponds to. */ | |
705 | unsigned bb_index; | |
706 | ||
707 | /* The dfs number of this node. */ | |
708 | unsigned dfs_num; | |
709 | }; | |
710 | ||
711 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
712 | for qsort. */ | |
713 | ||
714 | static int | |
715 | cmp_dfsnum (const void *a, const void *b) | |
716 | { | |
3d9a9f94 KG |
717 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
718 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
719 | |
720 | return (int) da->dfs_num - (int) db->dfs_num; | |
721 | } | |
722 | ||
723 | /* Among the intervals starting at the N points specified in DEFS, find | |
724 | the one that contains S, and return its bb_index. */ | |
725 | ||
726 | static unsigned | |
727 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
728 | { | |
729 | unsigned f = 0, t = n, m; | |
730 | ||
731 | while (t > f + 1) | |
732 | { | |
733 | m = (f + t) / 2; | |
734 | if (defs[m].dfs_num <= s) | |
735 | f = m; | |
736 | else | |
737 | t = m; | |
738 | } | |
739 | ||
740 | return defs[f].bb_index; | |
741 | } | |
742 | ||
743 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
744 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
745 | ||
746 | static void | |
747 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
748 | { | |
f074ff6c ZD |
749 | bitmap_iterator bi; |
750 | unsigned i, b, p, u, top; | |
751 | bitmap live_phis; | |
752 | basic_block def_bb, use_bb; | |
753 | edge e; | |
754 | edge_iterator ei; | |
755 | bitmap to_remove; | |
756 | struct dom_dfsnum *defs; | |
757 | unsigned n_defs, adef; | |
758 | ||
759 | if (bitmap_empty_p (uses)) | |
760 | { | |
761 | bitmap_clear (phis); | |
762 | return; | |
763 | } | |
764 | ||
765 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
766 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
767 | to_remove = BITMAP_ALLOC (NULL); | |
768 | bitmap_and_compl (to_remove, kills, uses); | |
769 | bitmap_and_compl_into (phis, to_remove); | |
770 | if (bitmap_empty_p (phis)) | |
771 | { | |
772 | BITMAP_FREE (to_remove); | |
773 | return; | |
774 | } | |
775 | ||
776 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
777 | liveness information, as that may be linear in the size of CFG, and if | |
778 | there are lot of different variables to rewrite, this may lead to quadratic | |
779 | behavior. | |
780 | ||
781 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
782 | then for each of them find the nearest def that dominates them. If this | |
783 | def is a phi node, we mark it live, and if it was not live before, we | |
784 | add the predecessors of its basic block to the worklist. | |
b8698a0f | 785 | |
f074ff6c ZD |
786 | To quickly locate the nearest def that dominates use, we use dfs numbering |
787 | of the dominance tree (that is already available in order to speed up | |
788 | queries). For each def, we have the interval given by the dfs number on | |
789 | entry to and on exit from the corresponding subtree in the dominance tree. | |
790 | The nearest dominator for a given use is the smallest of these intervals | |
791 | that contains entry and exit dfs numbers for the basic block with the use. | |
792 | If we store the bounds for all the uses to an array and sort it, we can | |
793 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
794 | bitmap_ior (to_remove, kills, phis); | |
795 | n_defs = bitmap_count_bits (to_remove); | |
796 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
797 | defs[0].bb_index = 1; | |
798 | defs[0].dfs_num = 0; | |
799 | adef = 1; | |
800 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
801 | { | |
06e28de2 | 802 | def_bb = BASIC_BLOCK_FOR_FN (cfun, i); |
f074ff6c ZD |
803 | defs[adef].bb_index = i; |
804 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
805 | defs[adef + 1].bb_index = i; | |
806 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
807 | adef += 2; | |
808 | } | |
809 | BITMAP_FREE (to_remove); | |
810 | gcc_assert (adef == 2 * n_defs + 1); | |
811 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
812 | gcc_assert (defs[0].bb_index == 1); | |
813 | ||
814 | /* Now each DEFS entry contains the number of the basic block to that the | |
815 | dfs number corresponds. Change them to the number of basic block that | |
816 | corresponds to the interval following the dfs number. Also, for the | |
817 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
818 | to the start of the following interval, not to the end of the current | |
819 | one). We use WORKLIST as a stack. */ | |
ef062b13 | 820 | auto_vec<int> worklist (n_defs + 1); |
9771b263 | 821 | worklist.quick_push (1); |
f074ff6c ZD |
822 | top = 1; |
823 | n_defs = 1; | |
824 | for (i = 1; i < adef; i++) | |
825 | { | |
826 | b = defs[i].bb_index; | |
827 | if (b == top) | |
828 | { | |
829 | /* This is a closing element. Interval corresponding to the top | |
830 | of the stack after removing it follows. */ | |
9771b263 DN |
831 | worklist.pop (); |
832 | top = worklist[worklist.length () - 1]; | |
f074ff6c ZD |
833 | defs[n_defs].bb_index = top; |
834 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
835 | } | |
836 | else | |
837 | { | |
838 | /* Opening element. Nothing to do, just push it to the stack and move | |
839 | it to the correct position. */ | |
840 | defs[n_defs].bb_index = defs[i].bb_index; | |
841 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
9771b263 | 842 | worklist.quick_push (b); |
f074ff6c ZD |
843 | top = b; |
844 | } | |
845 | ||
846 | /* If this interval starts at the same point as the previous one, cancel | |
847 | the previous one. */ | |
848 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
849 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
850 | else | |
851 | n_defs++; | |
852 | } | |
9771b263 DN |
853 | worklist.pop (); |
854 | gcc_assert (worklist.is_empty ()); | |
f074ff6c ZD |
855 | |
856 | /* Now process the uses. */ | |
857 | live_phis = BITMAP_ALLOC (NULL); | |
858 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
859 | { | |
9771b263 | 860 | worklist.safe_push (i); |
f074ff6c ZD |
861 | } |
862 | ||
9771b263 | 863 | while (!worklist.is_empty ()) |
f074ff6c | 864 | { |
9771b263 | 865 | b = worklist.pop (); |
f074ff6c ZD |
866 | if (b == ENTRY_BLOCK) |
867 | continue; | |
868 | ||
869 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
870 | find the def that dominates the immediate dominator of USE_BB | |
871 | (the kill in USE_BB does not dominate the use). */ | |
872 | if (bitmap_bit_p (phis, b)) | |
873 | p = b; | |
874 | else | |
875 | { | |
06e28de2 DM |
876 | use_bb = get_immediate_dominator (CDI_DOMINATORS, |
877 | BASIC_BLOCK_FOR_FN (cfun, b)); | |
f074ff6c ZD |
878 | p = find_dfsnum_interval (defs, n_defs, |
879 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
880 | if (!bitmap_bit_p (phis, p)) | |
881 | continue; | |
882 | } | |
883 | ||
884 | /* If the phi node is already live, there is nothing to do. */ | |
fcaa4ca4 | 885 | if (!bitmap_set_bit (live_phis, p)) |
f074ff6c ZD |
886 | continue; |
887 | ||
fcaa4ca4 | 888 | /* Add the new uses to the worklist. */ |
06e28de2 | 889 | def_bb = BASIC_BLOCK_FOR_FN (cfun, p); |
f074ff6c ZD |
890 | FOR_EACH_EDGE (e, ei, def_bb->preds) |
891 | { | |
892 | u = e->src->index; | |
893 | if (bitmap_bit_p (uses, u)) | |
894 | continue; | |
895 | ||
1e5787ef ZD |
896 | /* In case there is a kill directly in the use block, do not record |
897 | the use (this is also necessary for correctness, as we assume that | |
898 | uses dominated by a def directly in their block have been filtered | |
899 | out before). */ | |
900 | if (bitmap_bit_p (kills, u)) | |
901 | continue; | |
902 | ||
f074ff6c | 903 | bitmap_set_bit (uses, u); |
9771b263 | 904 | worklist.safe_push (u); |
f074ff6c ZD |
905 | } |
906 | } | |
907 | ||
f074ff6c ZD |
908 | bitmap_copy (phis, live_phis); |
909 | BITMAP_FREE (live_phis); | |
910 | free (defs); | |
911 | } | |
7256233c | 912 | |
7256233c DN |
913 | /* Return the set of blocks where variable VAR is defined and the blocks |
914 | where VAR is live on entry (livein). Return NULL, if no entry is | |
915 | found in DEF_BLOCKS. */ | |
916 | ||
526ceb68 | 917 | static inline def_blocks * |
7256233c DN |
918 | find_def_blocks_for (tree var) |
919 | { | |
526ceb68 | 920 | def_blocks *p = &get_common_info (var)->def_blocks; |
b4e209fd RG |
921 | if (!p->def_blocks) |
922 | return NULL; | |
923 | return p; | |
7256233c DN |
924 | } |
925 | ||
926 | ||
2ce79879 ZD |
927 | /* Marks phi node PHI in basic block BB for rewrite. */ |
928 | ||
929 | static void | |
538dd0b7 | 930 | mark_phi_for_rewrite (basic_block bb, gphi *phi) |
2ce79879 | 931 | { |
538dd0b7 | 932 | vec<gphi *> phis; |
580b2c2e | 933 | unsigned n, idx = bb->index; |
2ce79879 | 934 | |
726a989a | 935 | if (rewrite_uses_p (phi)) |
2ce79879 | 936 | return; |
38635499 | 937 | |
726a989a | 938 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
939 | |
940 | if (!blocks_with_phis_to_rewrite) | |
941 | return; | |
942 | ||
943 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
580b2c2e | 944 | |
8b1c6fd7 | 945 | n = (unsigned) last_basic_block_for_fn (cfun) + 1; |
9771b263 DN |
946 | if (phis_to_rewrite.length () < n) |
947 | phis_to_rewrite.safe_grow_cleared (n); | |
2ce79879 | 948 | |
9771b263 DN |
949 | phis = phis_to_rewrite[idx]; |
950 | phis.reserve (10); | |
2ce79879 | 951 | |
9771b263 DN |
952 | phis.safe_push (phi); |
953 | phis_to_rewrite[idx] = phis; | |
2ce79879 ZD |
954 | } |
955 | ||
7256233c | 956 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 957 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
958 | function assumes that the caller is incrementally updating the |
959 | existing SSA form, in which case VAR may be an SSA name instead of | |
960 | a symbol. | |
0bca51f0 DN |
961 | |
962 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
963 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
964 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
965 | |
966 | static void | |
0bca51f0 | 967 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
968 | { |
969 | unsigned bb_index; | |
970 | edge e; | |
538dd0b7 | 971 | gphi *phi; |
7256233c DN |
972 | basic_block bb; |
973 | bitmap_iterator bi; | |
526ceb68 | 974 | def_blocks *def_map = find_def_blocks_for (var); |
7256233c DN |
975 | |
976 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
977 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
978 | ||
f074ff6c ZD |
979 | /* Remove obviously useless phi nodes. */ |
980 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
981 | def_map->livein_blocks); | |
7256233c DN |
982 | |
983 | /* And insert the PHI nodes. */ | |
f074ff6c | 984 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c | 985 | { |
06e28de2 | 986 | bb = BASIC_BLOCK_FOR_FN (cfun, bb_index); |
95dd3097 ZD |
987 | if (update_p) |
988 | mark_block_for_update (bb); | |
7256233c | 989 | |
fa5556de RB |
990 | if (dump_file && (dump_flags & TDF_DETAILS)) |
991 | { | |
992 | fprintf (dump_file, "creating PHI node in block #%d for ", bb_index); | |
993 | print_generic_expr (dump_file, var, TDF_SLIM); | |
994 | fprintf (dump_file, "\n"); | |
995 | } | |
726a989a | 996 | phi = NULL; |
38635499 DN |
997 | |
998 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 999 | { |
84d65814 DN |
1000 | /* If we are rewriting SSA names, create the LHS of the PHI |
1001 | node by duplicating VAR. This is useful in the case of | |
1002 | pointers, to also duplicate pointer attributes (alias | |
1003 | information, in particular). */ | |
7256233c | 1004 | edge_iterator ei; |
84d65814 | 1005 | tree new_lhs; |
0bca51f0 | 1006 | |
4ad14919 | 1007 | gcc_checking_assert (update_p); |
dcc748dd RG |
1008 | new_lhs = duplicate_ssa_name (var, NULL); |
1009 | phi = create_phi_node (new_lhs, bb); | |
84d65814 | 1010 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1011 | |
1012 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1013 | every argument so that rewrite_update_phi_arguments knows | |
1014 | which name is this PHI node replacing. If VAR is a | |
1015 | symbol marked for renaming, this is not necessary, the | |
1016 | renamer will use the symbol on the LHS to get its | |
1017 | reaching definition. */ | |
7256233c | 1018 | FOR_EACH_EDGE (e, ei, bb->preds) |
9e227d60 | 1019 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
7256233c | 1020 | } |
84d65814 DN |
1021 | else |
1022 | { | |
b5b8b0ac | 1023 | tree tracked_var; |
3a56edc7 | 1024 | |
4ad14919 | 1025 | gcc_checking_assert (DECL_P (var)); |
e24c4814 | 1026 | phi = create_phi_node (var, bb); |
3a56edc7 AO |
1027 | |
1028 | tracked_var = target_for_debug_bind (var); | |
1029 | if (tracked_var) | |
b5b8b0ac | 1030 | { |
355fe088 TS |
1031 | gimple *note = gimple_build_debug_bind (tracked_var, |
1032 | PHI_RESULT (phi), | |
b5b8b0ac AO |
1033 | phi); |
1034 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1035 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1036 | } | |
84d65814 | 1037 | } |
0bca51f0 DN |
1038 | |
1039 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1040 | set_register_defs (phi, true); |
2ce79879 | 1041 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1042 | } |
1043 | } | |
1044 | ||
b4e209fd | 1045 | /* Sort var_infos after DECL_UID of their var. */ |
d9ed2fbd RG |
1046 | |
1047 | static int | |
b4e209fd | 1048 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
d9ed2fbd | 1049 | { |
526ceb68 TS |
1050 | const var_info *defa = *(var_info * const *)a; |
1051 | const var_info *defb = *(var_info * const *)b; | |
d9ed2fbd RG |
1052 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1053 | return -1; | |
1054 | else | |
1055 | return 1; | |
1056 | } | |
7256233c | 1057 | |
7256233c DN |
1058 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1059 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1060 | the flowgraph. */ |
7256233c DN |
1061 | |
1062 | static void | |
0fc555fb | 1063 | insert_phi_nodes (bitmap_head *dfs) |
7256233c | 1064 | { |
c203e8a7 | 1065 | hash_table<var_info_hasher>::iterator hi; |
d9ed2fbd | 1066 | unsigned i; |
526ceb68 | 1067 | var_info *info; |
7256233c DN |
1068 | |
1069 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
b8698a0f | 1070 | |
977472e8 RB |
1071 | /* When the gimplifier introduces SSA names it cannot easily avoid |
1072 | situations where abnormal edges added by CFG construction break | |
1073 | the use-def dominance requirement. For this case rewrite SSA | |
1074 | names with broken use-def dominance out-of-SSA and register them | |
1075 | for PHI insertion. We only need to do this if abnormal edges | |
1076 | can appear in the function. */ | |
1077 | tree name; | |
1078 | if (cfun->calls_setjmp | |
1079 | || cfun->has_nonlocal_label) | |
1080 | FOR_EACH_SSA_NAME (i, name, cfun) | |
1081 | { | |
1082 | gimple *def_stmt = SSA_NAME_DEF_STMT (name); | |
1083 | if (SSA_NAME_IS_DEFAULT_DEF (name)) | |
1084 | continue; | |
1085 | ||
1086 | basic_block def_bb = gimple_bb (def_stmt); | |
1087 | imm_use_iterator it; | |
1088 | gimple *use_stmt; | |
1089 | bool need_phis = false; | |
1090 | FOR_EACH_IMM_USE_STMT (use_stmt, it, name) | |
1091 | { | |
1092 | basic_block use_bb = gimple_bb (use_stmt); | |
1093 | if (use_bb != def_bb | |
1094 | && ! dominated_by_p (CDI_DOMINATORS, use_bb, def_bb)) | |
1095 | need_phis = true; | |
1096 | } | |
1097 | if (need_phis) | |
1098 | { | |
1099 | tree var = create_tmp_reg (TREE_TYPE (name)); | |
1100 | use_operand_p use_p; | |
1101 | FOR_EACH_IMM_USE_STMT (use_stmt, it, name) | |
1102 | { | |
1103 | basic_block use_bb = gimple_bb (use_stmt); | |
1104 | FOR_EACH_IMM_USE_ON_STMT (use_p, it) | |
1105 | SET_USE (use_p, var); | |
1106 | update_stmt (use_stmt); | |
1107 | set_livein_block (var, use_bb); | |
1108 | set_rewrite_uses (use_stmt, true); | |
1109 | bitmap_set_bit (interesting_blocks, use_bb->index); | |
1110 | } | |
1111 | def_operand_p def_p; | |
1112 | ssa_op_iter dit; | |
1113 | FOR_EACH_SSA_DEF_OPERAND (def_p, def_stmt, dit, SSA_OP_DEF) | |
1114 | if (DEF_FROM_PTR (def_p) == name) | |
1115 | SET_DEF (def_p, var); | |
1116 | update_stmt (def_stmt); | |
1117 | set_def_block (var, def_bb, false); | |
1118 | set_register_defs (def_stmt, true); | |
1119 | bitmap_set_bit (interesting_blocks, def_bb->index); | |
1120 | release_ssa_name (name); | |
1121 | } | |
1122 | } | |
1123 | ||
526ceb68 | 1124 | auto_vec<var_info *> vars (var_infos->elements ()); |
c203e8a7 | 1125 | FOR_EACH_HASH_TABLE_ELEMENT (*var_infos, info, var_info_p, hi) |
8812aab1 | 1126 | if (info->info.need_phi_state != NEED_PHI_STATE_NO) |
9771b263 | 1127 | vars.quick_push (info); |
d9ed2fbd | 1128 | |
e68c7b43 RG |
1129 | /* Do two stages to avoid code generation differences for UID |
1130 | differences but no UID ordering differences. */ | |
9771b263 | 1131 | vars.qsort (insert_phi_nodes_compare_var_infos); |
e68c7b43 | 1132 | |
9771b263 | 1133 | FOR_EACH_VEC_ELT (vars, i, info) |
5f240ec4 | 1134 | { |
8812aab1 | 1135 | bitmap idf = compute_idf (info->info.def_blocks.def_blocks, dfs); |
b4e209fd | 1136 | insert_phi_nodes_for (info->var, idf, false); |
e68c7b43 RG |
1137 | BITMAP_FREE (idf); |
1138 | } | |
1139 | ||
6de9cd9a DN |
1140 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1141 | } | |
1142 | ||
1143 | ||
38635499 DN |
1144 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1145 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1146 | |
cfaab3a9 | 1147 | static void |
38635499 | 1148 | register_new_def (tree def, tree sym) |
7256233c | 1149 | { |
526ceb68 | 1150 | common_info *info = get_common_info (sym); |
7256233c | 1151 | tree currdef; |
b8698a0f | 1152 | |
7256233c DN |
1153 | /* If this variable is set in a single basic block and all uses are |
1154 | dominated by the set(s) in that single basic block, then there is | |
1155 | no reason to record anything for this variable in the block local | |
1156 | definition stacks. Doing so just wastes time and memory. | |
1157 | ||
1158 | This is the same test to prune the set of variables which may | |
1159 | need PHI nodes. So we just use that information since it's already | |
1160 | computed and available for us to use. */ | |
8812aab1 | 1161 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
7256233c | 1162 | { |
8812aab1 | 1163 | info->current_def = def; |
7256233c DN |
1164 | return; |
1165 | } | |
1166 | ||
8812aab1 | 1167 | currdef = info->current_def; |
7256233c | 1168 | |
38635499 DN |
1169 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1170 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1171 | in the stack so that we know which symbol is being defined by | |
1172 | this SSA name when we unwind the stack. */ | |
1173 | if (currdef && !is_gimple_reg (sym)) | |
9771b263 | 1174 | block_defs_stack.safe_push (sym); |
7256233c | 1175 | |
38635499 DN |
1176 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1177 | stack is later used by the dominator tree callbacks to restore | |
1178 | the reaching definitions for all the variables defined in the | |
1179 | block after a recursive visit to all its immediately dominated | |
1180 | blocks. If there is no current reaching definition, then just | |
1181 | record the underlying _DECL node. */ | |
9771b263 | 1182 | block_defs_stack.safe_push (currdef ? currdef : sym); |
38635499 DN |
1183 | |
1184 | /* Set the current reaching definition for SYM to be DEF. */ | |
8812aab1 | 1185 | info->current_def = def; |
7256233c DN |
1186 | } |
1187 | ||
1188 | ||
6de9cd9a DN |
1189 | /* Perform a depth-first traversal of the dominator tree looking for |
1190 | variables to rename. BB is the block where to start searching. | |
1191 | Renaming is a five step process: | |
1192 | ||
1193 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1194 | registered as the current definition for the corresponding variable. | |
1195 | ||
1196 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1197 | rewritten with their corresponding reaching definition. DEF and | |
1198 | VDEF targets are registered as new definitions. | |
b8698a0f | 1199 | |
6de9cd9a DN |
1200 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1201 | argument corresponding to BB is replaced with its current reaching | |
1202 | definition. | |
1203 | ||
1204 | 4- Recursively rewrite every dominator child block of BB. | |
1205 | ||
1206 | 5- Restore (in reverse order) the current reaching definition for every | |
1207 | new definition introduced in this block. This is done so that when | |
1208 | we return from the recursive call, all the current reaching | |
1209 | definitions are restored to the names that were valid in the | |
1210 | dominator parent of BB. */ | |
1211 | ||
7256233c | 1212 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1213 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1214 | |
7256233c DN |
1215 | static tree |
1216 | get_reaching_def (tree var) | |
1217 | { | |
526ceb68 | 1218 | common_info *info = get_common_info (var); |
38635499 | 1219 | tree currdef; |
b8698a0f | 1220 | |
7256233c | 1221 | /* Lookup the current reaching definition for VAR. */ |
8812aab1 | 1222 | currdef = info->current_def; |
5f240ec4 | 1223 | |
7256233c DN |
1224 | /* If there is no reaching definition for VAR, create and register a |
1225 | default definition for it (if needed). */ | |
38635499 | 1226 | if (currdef == NULL_TREE) |
7256233c | 1227 | { |
38635499 | 1228 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
bd8d431f RB |
1229 | if (! sym) |
1230 | sym = create_tmp_reg (TREE_TYPE (var)); | |
32244553 | 1231 | currdef = get_or_create_ssa_default_def (cfun, sym); |
7256233c DN |
1232 | } |
1233 | ||
1234 | /* Return the current reaching definition for VAR, or the default | |
1235 | definition, if we had to create one. */ | |
38635499 | 1236 | return currdef; |
7256233c DN |
1237 | } |
1238 | ||
1239 | ||
ddb555ed JJ |
1240 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1241 | ||
1242 | static void | |
355fe088 | 1243 | rewrite_debug_stmt_uses (gimple *stmt) |
ddb555ed JJ |
1244 | { |
1245 | use_operand_p use_p; | |
1246 | ssa_op_iter iter; | |
1247 | bool update = false; | |
1248 | ||
1249 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1250 | { | |
5f564b8f | 1251 | tree var = USE_FROM_PTR (use_p), def; |
526ceb68 | 1252 | common_info *info = get_common_info (var); |
4ad14919 | 1253 | gcc_checking_assert (DECL_P (var)); |
8812aab1 | 1254 | def = info->current_def; |
5f564b8f | 1255 | if (!def) |
ddb555ed | 1256 | { |
fefa31b5 DM |
1257 | if (TREE_CODE (var) == PARM_DECL |
1258 | && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun))) | |
ddb555ed JJ |
1259 | { |
1260 | gimple_stmt_iterator gsi | |
fefa31b5 DM |
1261 | = |
1262 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1263 | int lim; |
1264 | /* Search a few source bind stmts at the start of first bb to | |
1265 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1266 | for (lim = 32; | |
1267 | !gsi_end_p (gsi) && lim > 0; | |
1268 | gsi_next (&gsi), lim--) | |
1269 | { | |
355fe088 | 1270 | gimple *gstmt = gsi_stmt (gsi); |
ddb555ed JJ |
1271 | if (!gimple_debug_source_bind_p (gstmt)) |
1272 | break; | |
1273 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1274 | { | |
1275 | def = gimple_debug_source_bind_get_var (gstmt); | |
1276 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1277 | break; | |
1278 | else | |
1279 | def = NULL_TREE; | |
1280 | } | |
1281 | } | |
1282 | /* If not, add a new source bind stmt. */ | |
1283 | if (def == NULL_TREE) | |
1284 | { | |
355fe088 | 1285 | gimple *def_temp; |
ddb555ed JJ |
1286 | def = make_node (DEBUG_EXPR_DECL); |
1287 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1288 | DECL_ARTIFICIAL (def) = 1; | |
1289 | TREE_TYPE (def) = TREE_TYPE (var); | |
899ca90e | 1290 | SET_DECL_MODE (def, DECL_MODE (var)); |
fefa31b5 DM |
1291 | gsi = |
1292 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1293 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); |
1294 | } | |
1295 | update = true; | |
1296 | } | |
1297 | } | |
1298 | else | |
15923c25 | 1299 | { |
8812aab1 | 1300 | /* Check if info->current_def can be trusted. */ |
5f564b8f MM |
1301 | basic_block bb = gimple_bb (stmt); |
1302 | basic_block def_bb | |
1303 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1304 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1305 | ||
1306 | /* If definition is in current bb, it is fine. */ | |
1307 | if (bb == def_bb) | |
1308 | ; | |
1309 | /* If definition bb doesn't dominate the current bb, | |
1310 | it can't be used. */ | |
1311 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1312 | def = NULL; | |
1313 | /* If there is just one definition and dominates the current | |
1314 | bb, it is fine. */ | |
8812aab1 | 1315 | else if (info->need_phi_state == NEED_PHI_STATE_NO) |
5f564b8f MM |
1316 | ; |
1317 | else | |
15923c25 | 1318 | { |
526ceb68 | 1319 | def_blocks *db_p = get_def_blocks_for (info); |
15923c25 | 1320 | |
5f564b8f MM |
1321 | /* If there are some non-debug uses in the current bb, |
1322 | it is fine. */ | |
1323 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
15923c25 | 1324 | ; |
5f564b8f | 1325 | /* Otherwise give up for now. */ |
15923c25 | 1326 | else |
5f564b8f | 1327 | def = NULL; |
15923c25 JJ |
1328 | } |
1329 | } | |
ddb555ed JJ |
1330 | if (def == NULL) |
1331 | { | |
1332 | gimple_debug_bind_reset_value (stmt); | |
1333 | update_stmt (stmt); | |
1334 | return; | |
1335 | } | |
1336 | SET_USE (use_p, def); | |
1337 | } | |
1338 | if (update) | |
1339 | update_stmt (stmt); | |
1340 | } | |
1341 | ||
7256233c DN |
1342 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1343 | the block with its immediate reaching definitions. Update the current | |
1344 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1345 | |
1346 | static void | |
5f33a4fc | 1347 | rewrite_stmt (gimple_stmt_iterator *si) |
5f240ec4 | 1348 | { |
7256233c DN |
1349 | use_operand_p use_p; |
1350 | def_operand_p def_p; | |
1351 | ssa_op_iter iter; | |
355fe088 | 1352 | gimple *stmt = gsi_stmt (*si); |
7256233c | 1353 | |
7256233c DN |
1354 | /* If mark_def_sites decided that we don't need to rewrite this |
1355 | statement, ignore it. */ | |
95dd3097 | 1356 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1357 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1358 | return; |
5f240ec4 ZD |
1359 | |
1360 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1361 | { |
1362 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1363 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1364 | fprintf (dump_file, "\n"); |
1365 | } | |
5f240ec4 | 1366 | |
38635499 | 1367 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1368 | if (rewrite_uses_p (stmt)) |
ddb555ed JJ |
1369 | { |
1370 | if (is_gimple_debug (stmt)) | |
1371 | rewrite_debug_stmt_uses (stmt); | |
1372 | else | |
39c58b3a | 1373 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
ddb555ed JJ |
1374 | { |
1375 | tree var = USE_FROM_PTR (use_p); | |
381cdae4 RB |
1376 | if (TREE_CODE (var) == SSA_NAME) |
1377 | continue; | |
4ad14919 | 1378 | gcc_checking_assert (DECL_P (var)); |
ddb555ed JJ |
1379 | SET_USE (use_p, get_reaching_def (var)); |
1380 | } | |
1381 | } | |
5f240ec4 | 1382 | |
38635499 | 1383 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1384 | if (register_defs_p (stmt)) |
39c58b3a | 1385 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
1386 | { |
1387 | tree var = DEF_FROM_PTR (def_p); | |
5f33a4fc | 1388 | tree name; |
b5b8b0ac | 1389 | tree tracked_var; |
5f33a4fc | 1390 | |
381cdae4 RB |
1391 | if (TREE_CODE (var) == SSA_NAME) |
1392 | continue; | |
4ad14919 | 1393 | gcc_checking_assert (DECL_P (var)); |
5f33a4fc RG |
1394 | |
1395 | if (gimple_clobber_p (stmt) | |
1396 | && is_gimple_reg (var)) | |
1397 | { | |
1398 | /* If we rewrite a DECL into SSA form then drop its | |
1399 | clobber stmts and replace uses with a new default def. */ | |
8813a647 | 1400 | gcc_checking_assert (VAR_P (var) && !gimple_vdef (stmt)); |
5f33a4fc RG |
1401 | gsi_replace (si, gimple_build_nop (), true); |
1402 | register_new_def (get_or_create_ssa_default_def (cfun, var), var); | |
1403 | break; | |
1404 | } | |
1405 | ||
1406 | name = make_ssa_name (var, stmt); | |
b5b8b0ac | 1407 | SET_DEF (def_p, name); |
38635499 | 1408 | register_new_def (DEF_FROM_PTR (def_p), var); |
b5b8b0ac AO |
1409 | |
1410 | tracked_var = target_for_debug_bind (var); | |
1411 | if (tracked_var) | |
1412 | { | |
355fe088 | 1413 | gimple *note = gimple_build_debug_bind (tracked_var, name, stmt); |
5f33a4fc | 1414 | gsi_insert_after (si, note, GSI_SAME_STMT); |
b5b8b0ac | 1415 | } |
0bca51f0 | 1416 | } |
5f240ec4 | 1417 | } |
6de9cd9a | 1418 | |
7256233c | 1419 | |
6de9cd9a DN |
1420 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1421 | PHI nodes. For every PHI node found, add a new argument containing the | |
1422 | current reaching definition for the variable and the edge through which | |
471854f8 | 1423 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1424 | |
1425 | static void | |
ccf5c864 | 1426 | rewrite_add_phi_arguments (basic_block bb) |
6de9cd9a DN |
1427 | { |
1428 | edge e; | |
628f6a4e | 1429 | edge_iterator ei; |
6de9cd9a | 1430 | |
628f6a4e | 1431 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1432 | { |
538dd0b7 DM |
1433 | gphi *phi; |
1434 | gphi_iterator gsi; | |
6de9cd9a | 1435 | |
726a989a RB |
1436 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1437 | gsi_next (&gsi)) | |
6de9cd9a | 1438 | { |
1ee62b92 | 1439 | tree currdef, res, argvar; |
ffc5b2bb | 1440 | location_t loc; |
f5045c96 | 1441 | |
538dd0b7 | 1442 | phi = gsi.phi (); |
ffc5b2bb | 1443 | res = gimple_phi_result (phi); |
1ee62b92 PG |
1444 | /* If we have pre-existing PHI (via the GIMPLE FE) its args may |
1445 | be different vars than existing vars and they may be constants | |
1446 | as well. Note the following supports partial SSA for PHI args. */ | |
1447 | argvar = gimple_phi_arg_def (phi, e->dest_idx); | |
1448 | if (argvar && ! DECL_P (argvar)) | |
1449 | continue; | |
1450 | if (!argvar) | |
1451 | argvar = SSA_NAME_VAR (res); | |
1452 | currdef = get_reaching_def (argvar); | |
ffc5b2bb RB |
1453 | /* Virtual operand PHI args do not need a location. */ |
1454 | if (virtual_operand_p (res)) | |
1455 | loc = UNKNOWN_LOCATION; | |
1456 | else | |
1457 | loc = gimple_location (SSA_NAME_DEF_STMT (currdef)); | |
1458 | add_phi_arg (phi, currdef, e, loc); | |
6de9cd9a DN |
1459 | } |
1460 | } | |
1461 | } | |
1462 | ||
4d9192b5 TS |
1463 | class rewrite_dom_walker : public dom_walker |
1464 | { | |
1465 | public: | |
dc3b4a20 RB |
1466 | rewrite_dom_walker (cdi_direction direction) |
1467 | : dom_walker (direction, ALL_BLOCKS, NULL) {} | |
4d9192b5 | 1468 | |
3daacdcd | 1469 | virtual edge before_dom_children (basic_block); |
4d9192b5 TS |
1470 | virtual void after_dom_children (basic_block); |
1471 | }; | |
1472 | ||
ccf5c864 PB |
1473 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1474 | of reaching definitions for new SSA names produced in this block | |
1475 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1476 | block. */ | |
1477 | ||
3daacdcd | 1478 | edge |
4d9192b5 | 1479 | rewrite_dom_walker::before_dom_children (basic_block bb) |
ccf5c864 | 1480 | { |
ccf5c864 PB |
1481 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1482 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1483 | ||
1484 | /* Mark the unwind point for this block. */ | |
9771b263 | 1485 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
1486 | |
1487 | /* Step 1. Register new definitions for every PHI node in the block. | |
1488 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1489 | node introduces a new version for the associated variable. */ | |
538dd0b7 DM |
1490 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1491 | gsi_next (&gsi)) | |
ccf5c864 | 1492 | { |
39c58b3a | 1493 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
ccf5c864 PB |
1494 | register_new_def (result, SSA_NAME_VAR (result)); |
1495 | } | |
1496 | ||
1497 | /* Step 2. Rewrite every variable used in each statement in the block | |
1498 | with its immediate reaching definitions. Update the current definition | |
1499 | of a variable when a new real or virtual definition is found. */ | |
d7c028c0 | 1500 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
538dd0b7 DM |
1501 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1502 | gsi_next (&gsi)) | |
5f33a4fc | 1503 | rewrite_stmt (&gsi); |
ccf5c864 PB |
1504 | |
1505 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1506 | For every PHI node found, add a new argument containing the current | |
1507 | reaching definition for the variable and the edge through which that | |
1508 | definition is reaching the PHI node. */ | |
1509 | rewrite_add_phi_arguments (bb); | |
3daacdcd JL |
1510 | |
1511 | return NULL; | |
ccf5c864 PB |
1512 | } |
1513 | ||
1514 | ||
7256233c | 1515 | |
38635499 DN |
1516 | /* Called after visiting all the statements in basic block BB and all |
1517 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a | 1518 | |
4d9192b5 TS |
1519 | void |
1520 | rewrite_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
6de9cd9a | 1521 | { |
9fae925b | 1522 | /* Restore CURRDEFS to its original state. */ |
9771b263 | 1523 | while (block_defs_stack.length () > 0) |
6de9cd9a | 1524 | { |
9771b263 | 1525 | tree tmp = block_defs_stack.pop (); |
6de9cd9a DN |
1526 | tree saved_def, var; |
1527 | ||
9fae925b JL |
1528 | if (tmp == NULL_TREE) |
1529 | break; | |
1530 | ||
6de9cd9a DN |
1531 | if (TREE_CODE (tmp) == SSA_NAME) |
1532 | { | |
38635499 DN |
1533 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1534 | current definition of its underlying variable. Note that | |
1535 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1536 | being defined is stored in the next slot in the stack. | |
1537 | This mechanism is needed because an SSA name for a | |
1538 | non-register symbol may be the definition for more than | |
1539 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1540 | saved_def = tmp; |
1541 | var = SSA_NAME_VAR (saved_def); | |
38635499 | 1542 | if (!is_gimple_reg (var)) |
9771b263 | 1543 | var = block_defs_stack.pop (); |
6de9cd9a DN |
1544 | } |
1545 | else | |
1546 | { | |
38635499 DN |
1547 | /* If we recorded anything else, it must have been a _DECL |
1548 | node and its current reaching definition must have been | |
1549 | NULL. */ | |
6de9cd9a DN |
1550 | saved_def = NULL; |
1551 | var = tmp; | |
1552 | } | |
b8698a0f | 1553 | |
8812aab1 | 1554 | get_common_info (var)->current_def = saved_def; |
6de9cd9a DN |
1555 | } |
1556 | } | |
1557 | ||
1558 | ||
38635499 DN |
1559 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1560 | ||
24e47c76 | 1561 | DEBUG_FUNCTION void |
38635499 DN |
1562 | debug_decl_set (bitmap set) |
1563 | { | |
1564 | dump_decl_set (stderr, set); | |
5006671f | 1565 | fprintf (stderr, "\n"); |
38635499 DN |
1566 | } |
1567 | ||
1568 | ||
1569 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1570 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1571 | dumped. New levels are created when the dominator tree traversal | |
1572 | used for renaming enters a new sub-tree. */ | |
1573 | ||
1574 | void | |
1575 | dump_defs_stack (FILE *file, int n) | |
1576 | { | |
1577 | int i, j; | |
1578 | ||
1579 | fprintf (file, "\n\nRenaming stack"); | |
1580 | if (n > 0) | |
1581 | fprintf (file, " (up to %d levels)", n); | |
1582 | fprintf (file, "\n\n"); | |
1583 | ||
1584 | i = 1; | |
1585 | fprintf (file, "Level %d (current level)\n", i); | |
9771b263 | 1586 | for (j = (int) block_defs_stack.length () - 1; j >= 0; j--) |
38635499 DN |
1587 | { |
1588 | tree name, var; | |
b8698a0f | 1589 | |
9771b263 | 1590 | name = block_defs_stack[j]; |
38635499 DN |
1591 | if (name == NULL_TREE) |
1592 | { | |
1593 | i++; | |
1594 | if (n > 0 && i > n) | |
1595 | break; | |
1596 | fprintf (file, "\nLevel %d\n", i); | |
1597 | continue; | |
1598 | } | |
1599 | ||
1600 | if (DECL_P (name)) | |
1601 | { | |
1602 | var = name; | |
1603 | name = NULL_TREE; | |
1604 | } | |
1605 | else | |
1606 | { | |
1607 | var = SSA_NAME_VAR (name); | |
1608 | if (!is_gimple_reg (var)) | |
1609 | { | |
1610 | j--; | |
9771b263 | 1611 | var = block_defs_stack[j]; |
38635499 DN |
1612 | } |
1613 | } | |
1614 | ||
1615 | fprintf (file, " Previous CURRDEF ("); | |
ef6cb4c7 | 1616 | print_generic_expr (file, var); |
38635499 DN |
1617 | fprintf (file, ") = "); |
1618 | if (name) | |
ef6cb4c7 | 1619 | print_generic_expr (file, name); |
38635499 DN |
1620 | else |
1621 | fprintf (file, "<NIL>"); | |
1622 | fprintf (file, "\n"); | |
1623 | } | |
1624 | } | |
1625 | ||
1626 | ||
1627 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1628 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1629 | dumped. New levels are created when the dominator tree traversal | |
1630 | used for renaming enters a new sub-tree. */ | |
1631 | ||
24e47c76 | 1632 | DEBUG_FUNCTION void |
38635499 DN |
1633 | debug_defs_stack (int n) |
1634 | { | |
1635 | dump_defs_stack (stderr, n); | |
1636 | } | |
1637 | ||
1638 | ||
1639 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1640 | ||
1641 | void | |
1642 | dump_currdefs (FILE *file) | |
1643 | { | |
13714310 | 1644 | unsigned i; |
38635499 DN |
1645 | tree var; |
1646 | ||
9771b263 | 1647 | if (symbols_to_rename.is_empty ()) |
13714310 RG |
1648 | return; |
1649 | ||
38635499 | 1650 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
9771b263 | 1651 | FOR_EACH_VEC_ELT (symbols_to_rename, i, var) |
13714310 | 1652 | { |
526ceb68 | 1653 | common_info *info = get_common_info (var); |
13714310 | 1654 | fprintf (file, "CURRDEF ("); |
ef6cb4c7 | 1655 | print_generic_expr (file, var); |
13714310 | 1656 | fprintf (file, ") = "); |
8812aab1 | 1657 | if (info->current_def) |
ef6cb4c7 | 1658 | print_generic_expr (file, info->current_def); |
13714310 RG |
1659 | else |
1660 | fprintf (file, "<NIL>"); | |
1661 | fprintf (file, "\n"); | |
1662 | } | |
38635499 DN |
1663 | } |
1664 | ||
1665 | ||
1666 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1667 | ||
24e47c76 | 1668 | DEBUG_FUNCTION void |
38635499 DN |
1669 | debug_currdefs (void) |
1670 | { | |
1671 | dump_currdefs (stderr); | |
1672 | } | |
1673 | ||
1674 | ||
6de9cd9a DN |
1675 | /* Dump SSA information to FILE. */ |
1676 | ||
1677 | void | |
1678 | dump_tree_ssa (FILE *file) | |
1679 | { | |
6de9cd9a | 1680 | const char *funcname |
673fda6b | 1681 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1682 | |
38635499 | 1683 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1684 | |
b4e209fd | 1685 | dump_var_infos (file); |
38635499 DN |
1686 | dump_defs_stack (file, -1); |
1687 | dump_currdefs (file); | |
1688 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1689 | } |
1690 | ||
1691 | ||
1692 | /* Dump SSA information to stderr. */ | |
1693 | ||
24e47c76 | 1694 | DEBUG_FUNCTION void |
6de9cd9a DN |
1695 | debug_tree_ssa (void) |
1696 | { | |
1697 | dump_tree_ssa (stderr); | |
1698 | } | |
1699 | ||
1700 | ||
7256233c DN |
1701 | /* Dump statistics for the hash table HTAB. */ |
1702 | ||
1703 | static void | |
c203e8a7 | 1704 | htab_statistics (FILE *file, const hash_table<var_info_hasher> &htab) |
7256233c DN |
1705 | { |
1706 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
bf190e8d LC |
1707 | (long) htab.size (), |
1708 | (long) htab.elements (), | |
1709 | htab.collisions ()); | |
7256233c DN |
1710 | } |
1711 | ||
1712 | ||
6de9cd9a DN |
1713 | /* Dump SSA statistics on FILE. */ |
1714 | ||
1715 | void | |
1716 | dump_tree_ssa_stats (FILE *file) | |
1717 | { | |
c203e8a7 | 1718 | if (var_infos) |
38635499 | 1719 | { |
b4e209fd RG |
1720 | fprintf (file, "\nHash table statistics:\n"); |
1721 | fprintf (file, " var_infos: "); | |
c203e8a7 | 1722 | htab_statistics (file, *var_infos); |
b4e209fd | 1723 | fprintf (file, "\n"); |
38635499 | 1724 | } |
6de9cd9a DN |
1725 | } |
1726 | ||
1727 | ||
1728 | /* Dump SSA statistics on stderr. */ | |
1729 | ||
24e47c76 | 1730 | DEBUG_FUNCTION void |
6de9cd9a DN |
1731 | debug_tree_ssa_stats (void) |
1732 | { | |
1733 | dump_tree_ssa_stats (stderr); | |
1734 | } | |
1735 | ||
1736 | ||
b4e209fd | 1737 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
6de9cd9a | 1738 | |
bf190e8d | 1739 | int |
526ceb68 | 1740 | debug_var_infos_r (var_info **slot, FILE *file) |
7256233c | 1741 | { |
526ceb68 | 1742 | var_info *info = *slot; |
b8698a0f | 1743 | |
38635499 | 1744 | fprintf (file, "VAR: "); |
8812aab1 RG |
1745 | print_generic_expr (file, info->var, dump_flags); |
1746 | bitmap_print (file, info->info.def_blocks.def_blocks, | |
1747 | ", DEF_BLOCKS: { ", "}"); | |
1748 | bitmap_print (file, info->info.def_blocks.livein_blocks, | |
1749 | ", LIVEIN_BLOCKS: { ", "}"); | |
1750 | bitmap_print (file, info->info.def_blocks.phi_blocks, | |
1751 | ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1752 | |
7256233c DN |
1753 | return 1; |
1754 | } | |
6de9cd9a | 1755 | |
6de9cd9a | 1756 | |
b4e209fd | 1757 | /* Dump the VAR_INFOS hash table on FILE. */ |
38635499 DN |
1758 | |
1759 | void | |
b4e209fd | 1760 | dump_var_infos (FILE *file) |
38635499 DN |
1761 | { |
1762 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
c203e8a7 TS |
1763 | if (var_infos) |
1764 | var_infos->traverse <FILE *, debug_var_infos_r> (file); | |
38635499 DN |
1765 | } |
1766 | ||
1767 | ||
b4e209fd | 1768 | /* Dump the VAR_INFOS hash table on stderr. */ |
6de9cd9a | 1769 | |
24e47c76 | 1770 | DEBUG_FUNCTION void |
b4e209fd | 1771 | debug_var_infos (void) |
7256233c | 1772 | { |
b4e209fd | 1773 | dump_var_infos (stderr); |
7256233c | 1774 | } |
6de9cd9a | 1775 | |
5f240ec4 | 1776 | |
0bca51f0 | 1777 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1778 | |
0bca51f0 DN |
1779 | static inline void |
1780 | register_new_update_single (tree new_name, tree old_name) | |
1781 | { | |
526ceb68 | 1782 | common_info *info = get_common_info (old_name); |
8812aab1 | 1783 | tree currdef = info->current_def; |
5f240ec4 | 1784 | |
38635499 | 1785 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1786 | This stack is later used by the dominator tree callbacks to |
1787 | restore the reaching definitions for all the variables | |
1788 | defined in the block after a recursive visit to all its | |
1789 | immediately dominated blocks. */ | |
9771b263 DN |
1790 | block_defs_stack.reserve (2); |
1791 | block_defs_stack.quick_push (currdef); | |
1792 | block_defs_stack.quick_push (old_name); | |
5f240ec4 | 1793 | |
0bca51f0 DN |
1794 | /* Set the current reaching definition for OLD_NAME to be |
1795 | NEW_NAME. */ | |
8812aab1 | 1796 | info->current_def = new_name; |
0bca51f0 | 1797 | } |
7256233c | 1798 | |
6de9cd9a | 1799 | |
0bca51f0 DN |
1800 | /* Register NEW_NAME to be the new reaching definition for all the |
1801 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1802 | replace old SSA names with new ones. */ | |
7256233c | 1803 | |
0bca51f0 DN |
1804 | static inline void |
1805 | register_new_update_set (tree new_name, bitmap old_names) | |
1806 | { | |
1807 | bitmap_iterator bi; | |
1808 | unsigned i; | |
7256233c | 1809 | |
0bca51f0 DN |
1810 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1811 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1812 | } |
1813 | ||
7256233c | 1814 | |
0bca51f0 | 1815 | |
84d65814 DN |
1816 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1817 | it is a symbol marked for renaming, replace it with USE_P's current | |
1818 | reaching definition. */ | |
1819 | ||
1820 | static inline void | |
1821 | maybe_replace_use (use_operand_p use_p) | |
1822 | { | |
1823 | tree rdef = NULL_TREE; | |
1824 | tree use = USE_FROM_PTR (use_p); | |
1825 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1826 | ||
13714310 | 1827 | if (marked_for_renaming (sym)) |
84d65814 DN |
1828 | rdef = get_reaching_def (sym); |
1829 | else if (is_old_name (use)) | |
1830 | rdef = get_reaching_def (use); | |
1831 | ||
1832 | if (rdef && rdef != use) | |
1833 | SET_USE (use_p, rdef); | |
1834 | } | |
1835 | ||
1836 | ||
b5b8b0ac AO |
1837 | /* Same as maybe_replace_use, but without introducing default stmts, |
1838 | returning false to indicate a need to do so. */ | |
1839 | ||
1840 | static inline bool | |
1841 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1842 | { | |
1843 | tree rdef = NULL_TREE; | |
1844 | tree use = USE_FROM_PTR (use_p); | |
1845 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1846 | ||
13714310 | 1847 | if (marked_for_renaming (sym)) |
8812aab1 | 1848 | rdef = get_var_info (sym)->info.current_def; |
b5b8b0ac AO |
1849 | else if (is_old_name (use)) |
1850 | { | |
8812aab1 | 1851 | rdef = get_ssa_name_ann (use)->info.current_def; |
b5b8b0ac AO |
1852 | /* We can't assume that, if there's no current definition, the |
1853 | default one should be used. It could be the case that we've | |
1854 | rearranged blocks so that the earlier definition no longer | |
1855 | dominates the use. */ | |
1856 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1857 | rdef = use; | |
1858 | } | |
1859 | else | |
1860 | rdef = use; | |
1861 | ||
1862 | if (rdef && rdef != use) | |
1863 | SET_USE (use_p, rdef); | |
1864 | ||
1865 | return rdef != NULL_TREE; | |
1866 | } | |
1867 | ||
1868 | ||
f6b9f2ff ML |
1869 | /* If DEF has x_5 = ASAN_POISON () as its current def, add |
1870 | ASAN_POISON_USE (x_5) stmt before GSI to denote the stmt writes into | |
1871 | a poisoned (out of scope) variable. */ | |
1872 | ||
1873 | static void | |
1874 | maybe_add_asan_poison_write (tree def, gimple_stmt_iterator *gsi) | |
1875 | { | |
1876 | tree cdef = get_current_def (def); | |
1877 | if (cdef != NULL | |
1878 | && TREE_CODE (cdef) == SSA_NAME | |
1879 | && gimple_call_internal_p (SSA_NAME_DEF_STMT (cdef), IFN_ASAN_POISON)) | |
1880 | { | |
1881 | gcall *call | |
1882 | = gimple_build_call_internal (IFN_ASAN_POISON_USE, 1, cdef); | |
1883 | gimple_set_location (call, gimple_location (gsi_stmt (*gsi))); | |
1884 | gsi_insert_before (gsi, call, GSI_SAME_STMT); | |
1885 | } | |
1886 | } | |
1887 | ||
1888 | ||
84d65814 DN |
1889 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1890 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1891 | register it as the current definition for the names replaced by | |
956623c1 | 1892 | DEF_P. Returns whether the statement should be removed. */ |
84d65814 | 1893 | |
956623c1 | 1894 | static inline bool |
355fe088 | 1895 | maybe_register_def (def_operand_p def_p, gimple *stmt, |
3a56edc7 | 1896 | gimple_stmt_iterator gsi) |
84d65814 DN |
1897 | { |
1898 | tree def = DEF_FROM_PTR (def_p); | |
1899 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
956623c1 | 1900 | bool to_delete = false; |
84d65814 | 1901 | |
38635499 DN |
1902 | /* If DEF is a naked symbol that needs renaming, create a new |
1903 | name for it. */ | |
13714310 | 1904 | if (marked_for_renaming (sym)) |
84d65814 DN |
1905 | { |
1906 | if (DECL_P (def)) | |
1907 | { | |
956623c1 MG |
1908 | if (gimple_clobber_p (stmt) && is_gimple_reg (sym)) |
1909 | { | |
8813a647 | 1910 | gcc_checking_assert (VAR_P (sym)); |
956623c1 MG |
1911 | /* Replace clobber stmts with a default def. This new use of a |
1912 | default definition may make it look like SSA_NAMEs have | |
1913 | conflicting lifetimes, so we need special code to let them | |
1914 | coalesce properly. */ | |
1915 | to_delete = true; | |
1916 | def = get_or_create_ssa_default_def (cfun, sym); | |
1917 | } | |
1918 | else | |
f6b9f2ff ML |
1919 | { |
1920 | if (asan_sanitize_use_after_scope ()) | |
1921 | maybe_add_asan_poison_write (def, &gsi); | |
1922 | def = make_ssa_name (def, stmt); | |
1923 | } | |
84d65814 | 1924 | SET_DEF (def_p, def); |
3a56edc7 | 1925 | |
956623c1 | 1926 | tree tracked_var = target_for_debug_bind (sym); |
3a56edc7 AO |
1927 | if (tracked_var) |
1928 | { | |
355fe088 | 1929 | gimple *note = gimple_build_debug_bind (tracked_var, def, stmt); |
c47987fa JJ |
1930 | /* If stmt ends the bb, insert the debug stmt on the single |
1931 | non-EH edge from the stmt. */ | |
1932 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1933 | { | |
1934 | basic_block bb = gsi_bb (gsi); | |
1935 | edge_iterator ei; | |
1936 | edge e, ef = NULL; | |
1937 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1938 | if (!(e->flags & EDGE_EH)) | |
1939 | { | |
4ad14919 | 1940 | gcc_checking_assert (!ef); |
c47987fa JJ |
1941 | ef = e; |
1942 | } | |
23d5ed5d AO |
1943 | /* If there are other predecessors to ef->dest, then |
1944 | there must be PHI nodes for the modified | |
1945 | variable, and therefore there will be debug bind | |
1946 | stmts after the PHI nodes. The debug bind notes | |
1947 | we'd insert would force the creation of a new | |
1948 | block (diverging codegen) and be redundant with | |
1949 | the post-PHI bind stmts, so don't add them. | |
1950 | ||
1951 | As for the exit edge, there wouldn't be redundant | |
1952 | bind stmts, but there wouldn't be a PC to bind | |
1953 | them to either, so avoid diverging the CFG. */ | |
1954 | if (ef && single_pred_p (ef->dest) | |
fefa31b5 | 1955 | && ef->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
23d5ed5d AO |
1956 | { |
1957 | /* If there were PHI nodes in the node, we'd | |
1958 | have to make sure the value we're binding | |
1959 | doesn't need rewriting. But there shouldn't | |
1960 | be PHI nodes in a single-predecessor block, | |
1961 | so we just add the note. */ | |
1962 | gsi_insert_on_edge_immediate (ef, note); | |
1963 | } | |
c47987fa JJ |
1964 | } |
1965 | else | |
1966 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
3a56edc7 | 1967 | } |
84d65814 DN |
1968 | } |
1969 | ||
1970 | register_new_update_single (def, sym); | |
1971 | } | |
1972 | else | |
1973 | { | |
1974 | /* If DEF is a new name, register it as a new definition | |
1975 | for all the names replaced by DEF. */ | |
1976 | if (is_new_name (def)) | |
1977 | register_new_update_set (def, names_replaced_by (def)); | |
1978 | ||
1979 | /* If DEF is an old name, register DEF as a new | |
1980 | definition for itself. */ | |
1981 | if (is_old_name (def)) | |
1982 | register_new_update_single (def, def); | |
1983 | } | |
956623c1 MG |
1984 | |
1985 | return to_delete; | |
84d65814 DN |
1986 | } |
1987 | ||
1988 | ||
0bca51f0 DN |
1989 | /* Update every variable used in the statement pointed-to by SI. The |
1990 | statement is assumed to be in SSA form already. Names in | |
1991 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1992 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1993 | will be registered as a new definition for their corresponding name | |
956623c1 | 1994 | in OLD_SSA_NAMES. Returns whether STMT should be removed. */ |
0bca51f0 | 1995 | |
956623c1 | 1996 | static bool |
355fe088 | 1997 | rewrite_update_stmt (gimple *stmt, gimple_stmt_iterator gsi) |
0bca51f0 | 1998 | { |
0bca51f0 DN |
1999 | use_operand_p use_p; |
2000 | def_operand_p def_p; | |
2001 | ssa_op_iter iter; | |
2002 | ||
0bca51f0 | 2003 | /* Only update marked statements. */ |
726a989a | 2004 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
956623c1 | 2005 | return false; |
0bca51f0 DN |
2006 | |
2007 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2008 | { | |
2009 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 2010 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
2011 | } |
2012 | ||
2013 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
2014 | symbol is marked for renaming. */ | |
726a989a | 2015 | if (rewrite_uses_p (stmt)) |
b5b8b0ac AO |
2016 | { |
2017 | if (is_gimple_debug (stmt)) | |
2018 | { | |
2019 | bool failed = false; | |
2020 | ||
2021 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
2022 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
2023 | { | |
2024 | failed = true; | |
2025 | break; | |
2026 | } | |
2027 | ||
2028 | if (failed) | |
2029 | { | |
2030 | /* DOM sometimes threads jumps in such a way that a | |
2031 | debug stmt ends up referencing a SSA variable that no | |
2032 | longer dominates the debug stmt, but such that all | |
2033 | incoming definitions refer to the same definition in | |
2034 | an earlier dominator. We could try to recover that | |
2035 | definition somehow, but this will have to do for now. | |
2036 | ||
2037 | Introducing a default definition, which is what | |
2038 | maybe_replace_use() would do in such cases, may | |
2039 | modify code generation, for the otherwise-unused | |
2040 | default definition would never go away, modifying SSA | |
2041 | version numbers all over. */ | |
2042 | gimple_debug_bind_reset_value (stmt); | |
2043 | update_stmt (stmt); | |
2044 | } | |
2045 | } | |
2046 | else | |
2047 | { | |
2048 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
2049 | maybe_replace_use (use_p); | |
2050 | } | |
2051 | } | |
0bca51f0 DN |
2052 | |
2053 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
2054 | Also register definitions for names whose underlying symbol is | |
2055 | marked for renaming. */ | |
956623c1 | 2056 | bool to_delete = false; |
726a989a | 2057 | if (register_defs_p (stmt)) |
5006671f | 2058 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
956623c1 MG |
2059 | to_delete |= maybe_register_def (def_p, stmt, gsi); |
2060 | ||
2061 | return to_delete; | |
0bca51f0 DN |
2062 | } |
2063 | ||
2064 | ||
2065 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
2066 | every PHI node found, check if any of its arguments is in | |
2067 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
2068 | definition, replace it. */ | |
2069 | ||
2070 | static void | |
ccf5c864 | 2071 | rewrite_update_phi_arguments (basic_block bb) |
0bca51f0 DN |
2072 | { |
2073 | edge e; | |
2074 | edge_iterator ei; | |
2ce79879 | 2075 | unsigned i; |
0bca51f0 DN |
2076 | |
2077 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2078 | { | |
538dd0b7 DM |
2079 | gphi *phi; |
2080 | vec<gphi *> phis; | |
0bca51f0 | 2081 | |
2ce79879 ZD |
2082 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
2083 | continue; | |
b8698a0f | 2084 | |
9771b263 DN |
2085 | phis = phis_to_rewrite[e->dest->index]; |
2086 | FOR_EACH_VEC_ELT (phis, i, phi) | |
0bca51f0 | 2087 | { |
f5045c96 | 2088 | tree arg, lhs_sym, reaching_def = NULL; |
0bca51f0 DN |
2089 | use_operand_p arg_p; |
2090 | ||
4ad14919 | 2091 | gcc_checking_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
2092 | |
2093 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2094 | arg = USE_FROM_PTR (arg_p); | |
2095 | ||
2096 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2097 | continue; | |
2098 | ||
726a989a | 2099 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 2100 | |
0bca51f0 DN |
2101 | if (arg == NULL_TREE) |
2102 | { | |
2103 | /* When updating a PHI node for a recently introduced | |
2104 | symbol we may find NULL arguments. That's why we | |
2105 | take the symbol from the LHS of the PHI node. */ | |
f5045c96 AM |
2106 | reaching_def = get_reaching_def (lhs_sym); |
2107 | ||
0bca51f0 DN |
2108 | } |
2109 | else | |
2110 | { | |
2111 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2112 | ||
13714310 | 2113 | if (marked_for_renaming (sym)) |
f5045c96 | 2114 | reaching_def = get_reaching_def (sym); |
0bca51f0 | 2115 | else if (is_old_name (arg)) |
f5045c96 AM |
2116 | reaching_def = get_reaching_def (arg); |
2117 | } | |
2118 | ||
2119 | /* Update the argument if there is a reaching def. */ | |
2120 | if (reaching_def) | |
2121 | { | |
620e594b | 2122 | location_t locus; |
f5045c96 AM |
2123 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); |
2124 | ||
2125 | SET_USE (arg_p, reaching_def); | |
f5045c96 | 2126 | |
ffc5b2bb RB |
2127 | /* Virtual operands do not need a location. */ |
2128 | if (virtual_operand_p (reaching_def)) | |
2129 | locus = UNKNOWN_LOCATION; | |
f5045c96 | 2130 | else |
ffc5b2bb | 2131 | { |
355fe088 | 2132 | gimple *stmt = SSA_NAME_DEF_STMT (reaching_def); |
538dd0b7 | 2133 | gphi *other_phi = dyn_cast <gphi *> (stmt); |
ffc5b2bb RB |
2134 | |
2135 | /* Single element PHI nodes behave like copies, so get the | |
2136 | location from the phi argument. */ | |
538dd0b7 DM |
2137 | if (other_phi |
2138 | && gimple_phi_num_args (other_phi) == 1) | |
2139 | locus = gimple_phi_arg_location (other_phi, 0); | |
ffc5b2bb RB |
2140 | else |
2141 | locus = gimple_location (stmt); | |
2142 | } | |
f5045c96 AM |
2143 | |
2144 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
0bca51f0 DN |
2145 | } |
2146 | ||
f5045c96 | 2147 | |
0bca51f0 DN |
2148 | if (e->flags & EDGE_ABNORMAL) |
2149 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2150 | } | |
2151 | } | |
2152 | } | |
2153 | ||
4d9192b5 TS |
2154 | class rewrite_update_dom_walker : public dom_walker |
2155 | { | |
2156 | public: | |
dc3b4a20 RB |
2157 | rewrite_update_dom_walker (cdi_direction direction) |
2158 | : dom_walker (direction, ALL_BLOCKS, NULL) {} | |
4d9192b5 | 2159 | |
3daacdcd | 2160 | virtual edge before_dom_children (basic_block); |
4d9192b5 TS |
2161 | virtual void after_dom_children (basic_block); |
2162 | }; | |
0bca51f0 | 2163 | |
ccf5c864 PB |
2164 | /* Initialization of block data structures for the incremental SSA |
2165 | update pass. Create a block local stack of reaching definitions | |
2166 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2167 | new definitions for every PHI node in the block. */ | |
2168 | ||
3daacdcd | 2169 | edge |
4d9192b5 | 2170 | rewrite_update_dom_walker::before_dom_children (basic_block bb) |
ccf5c864 | 2171 | { |
ccf5c864 | 2172 | bool is_abnormal_phi; |
ccf5c864 PB |
2173 | |
2174 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
427f99e2 | 2175 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
ccf5c864 PB |
2176 | bb->index); |
2177 | ||
2178 | /* Mark the unwind point for this block. */ | |
9771b263 | 2179 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
2180 | |
2181 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
3daacdcd | 2182 | return NULL; |
ccf5c864 PB |
2183 | |
2184 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2185 | edge. */ | |
31ff2426 | 2186 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
ccf5c864 PB |
2187 | |
2188 | /* If any of the PHI nodes is a replacement for a name in | |
2189 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2190 | register it as a new definition for its corresponding name. Also | |
2191 | register definitions for names whose underlying symbols are | |
2192 | marked for renaming. */ | |
538dd0b7 DM |
2193 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
2194 | gsi_next (&gsi)) | |
ccf5c864 PB |
2195 | { |
2196 | tree lhs, lhs_sym; | |
538dd0b7 | 2197 | gphi *phi = gsi.phi (); |
ccf5c864 PB |
2198 | |
2199 | if (!register_defs_p (phi)) | |
2200 | continue; | |
b8698a0f | 2201 | |
ccf5c864 PB |
2202 | lhs = gimple_phi_result (phi); |
2203 | lhs_sym = SSA_NAME_VAR (lhs); | |
2204 | ||
13714310 | 2205 | if (marked_for_renaming (lhs_sym)) |
ccf5c864 PB |
2206 | register_new_update_single (lhs, lhs_sym); |
2207 | else | |
2208 | { | |
2209 | ||
2210 | /* If LHS is a new name, register a new definition for all | |
2211 | the names replaced by LHS. */ | |
2212 | if (is_new_name (lhs)) | |
2213 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
b8698a0f | 2214 | |
ccf5c864 PB |
2215 | /* If LHS is an OLD name, register it as a new definition |
2216 | for itself. */ | |
2217 | if (is_old_name (lhs)) | |
2218 | register_new_update_single (lhs, lhs); | |
2219 | } | |
2220 | ||
2221 | if (is_abnormal_phi) | |
2222 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2223 | } | |
2224 | ||
2225 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
d7c028c0 | 2226 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
3a56edc7 | 2227 | { |
4ad14919 | 2228 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
538dd0b7 | 2229 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) |
956623c1 MG |
2230 | if (rewrite_update_stmt (gsi_stmt (gsi), gsi)) |
2231 | gsi_remove (&gsi, true); | |
2232 | else | |
2233 | gsi_next (&gsi); | |
3a56edc7 | 2234 | } |
ccf5c864 PB |
2235 | |
2236 | /* Step 3. Update PHI nodes. */ | |
2237 | rewrite_update_phi_arguments (bb); | |
3daacdcd JL |
2238 | |
2239 | return NULL; | |
ccf5c864 PB |
2240 | } |
2241 | ||
2242 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2243 | the current reaching definition of every name re-written in BB to | |
2244 | the original reaching definition before visiting BB. This | |
2245 | unwinding must be done in the opposite order to what is done in | |
2246 | register_new_update_set. */ | |
2247 | ||
4d9192b5 TS |
2248 | void |
2249 | rewrite_update_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
ccf5c864 | 2250 | { |
9771b263 | 2251 | while (block_defs_stack.length () > 0) |
ccf5c864 | 2252 | { |
9771b263 | 2253 | tree var = block_defs_stack.pop (); |
ccf5c864 | 2254 | tree saved_def; |
b8698a0f | 2255 | |
ccf5c864 PB |
2256 | /* NULL indicates the unwind stop point for this block (see |
2257 | rewrite_update_enter_block). */ | |
2258 | if (var == NULL) | |
2259 | return; | |
2260 | ||
9771b263 | 2261 | saved_def = block_defs_stack.pop (); |
8812aab1 | 2262 | get_common_info (var)->current_def = saved_def; |
ccf5c864 PB |
2263 | } |
2264 | } | |
2265 | ||
2266 | ||
0bca51f0 | 2267 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
b8698a0f | 2268 | form. |
0bca51f0 DN |
2269 | |
2270 | ENTRY indicates the block where to start. Every block dominated by | |
2271 | ENTRY will be rewritten. | |
2272 | ||
2273 | WHAT indicates what actions will be taken by the renamer (see enum | |
2274 | rewrite_mode). | |
2275 | ||
2276 | BLOCKS are the set of interesting blocks for the dominator walker | |
2277 | to process. If this set is NULL, then all the nodes dominated | |
2278 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2279 | are not present in BLOCKS are ignored. */ | |
2280 | ||
2281 | static void | |
ccf5c864 | 2282 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
0bca51f0 | 2283 | { |
0bca51f0 DN |
2284 | /* Rewrite all the basic blocks in the program. */ |
2285 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2286 | ||
4d9192b5 | 2287 | block_defs_stack.create (10); |
0bca51f0 | 2288 | |
4d9192b5 TS |
2289 | /* Recursively walk the dominator tree rewriting each statement in |
2290 | each basic block. */ | |
0bca51f0 | 2291 | if (what == REWRITE_ALL) |
4d9192b5 | 2292 | rewrite_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 | 2293 | else if (what == REWRITE_UPDATE) |
4d9192b5 | 2294 | rewrite_update_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 DN |
2295 | else |
2296 | gcc_unreachable (); | |
2297 | ||
0bca51f0 DN |
2298 | /* Debugging dumps. */ |
2299 | if (dump_file && (dump_flags & TDF_STATS)) | |
2300 | { | |
2301 | dump_dfa_stats (dump_file); | |
c203e8a7 | 2302 | if (var_infos) |
0bca51f0 DN |
2303 | dump_tree_ssa_stats (dump_file); |
2304 | } | |
b8698a0f | 2305 | |
9771b263 | 2306 | block_defs_stack.release (); |
0bca51f0 DN |
2307 | |
2308 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2309 | } | |
2310 | ||
4d9192b5 | 2311 | class mark_def_dom_walker : public dom_walker |
7256233c | 2312 | { |
4d9192b5 TS |
2313 | public: |
2314 | mark_def_dom_walker (cdi_direction direction); | |
2315 | ~mark_def_dom_walker (); | |
5f240ec4 | 2316 | |
3daacdcd | 2317 | virtual edge before_dom_children (basic_block); |
5f240ec4 | 2318 | |
4d9192b5 | 2319 | private: |
7256233c DN |
2320 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2321 | large enough to accommodate all the variables referenced in the | |
2322 | function, not just the ones we are renaming. */ | |
65d3284b | 2323 | bitmap m_kills; |
4d9192b5 | 2324 | }; |
6de9cd9a | 2325 | |
4d9192b5 | 2326 | mark_def_dom_walker::mark_def_dom_walker (cdi_direction direction) |
dc3b4a20 | 2327 | : dom_walker (direction, ALL_BLOCKS, NULL), m_kills (BITMAP_ALLOC (NULL)) |
4d9192b5 TS |
2328 | { |
2329 | } | |
7256233c | 2330 | |
4d9192b5 TS |
2331 | mark_def_dom_walker::~mark_def_dom_walker () |
2332 | { | |
65d3284b | 2333 | BITMAP_FREE (m_kills); |
4d9192b5 | 2334 | } |
7256233c | 2335 | |
4d9192b5 TS |
2336 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2337 | at the start of each block, and call mark_def_sites for each statement. */ | |
7256233c | 2338 | |
3daacdcd | 2339 | edge |
4d9192b5 TS |
2340 | mark_def_dom_walker::before_dom_children (basic_block bb) |
2341 | { | |
2342 | gimple_stmt_iterator gsi; | |
7256233c | 2343 | |
65d3284b | 2344 | bitmap_clear (m_kills); |
4d9192b5 | 2345 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
65d3284b | 2346 | mark_def_sites (bb, gsi_stmt (gsi), m_kills); |
3daacdcd | 2347 | return NULL; |
6de9cd9a DN |
2348 | } |
2349 | ||
38635499 DN |
2350 | /* Initialize internal data needed during renaming. */ |
2351 | ||
2352 | static void | |
2353 | init_ssa_renamer (void) | |
2354 | { | |
38635499 DN |
2355 | cfun->gimple_df->in_ssa_p = false; |
2356 | ||
2357 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
c203e8a7 TS |
2358 | gcc_assert (!var_infos); |
2359 | var_infos = new hash_table<var_info_hasher> | |
2360 | (vec_safe_length (cfun->local_decls)); | |
38635499 | 2361 | |
b4e209fd | 2362 | bitmap_obstack_initialize (&update_ssa_obstack); |
38635499 DN |
2363 | } |
2364 | ||
2365 | ||
2366 | /* Deallocate internal data structures used by the renamer. */ | |
2367 | ||
2368 | static void | |
2369 | fini_ssa_renamer (void) | |
2370 | { | |
c203e8a7 TS |
2371 | delete var_infos; |
2372 | var_infos = NULL; | |
38635499 | 2373 | |
b4e209fd RG |
2374 | bitmap_obstack_release (&update_ssa_obstack); |
2375 | ||
13714310 RG |
2376 | cfun->gimple_df->ssa_renaming_needed = 0; |
2377 | cfun->gimple_df->rename_vops = 0; | |
38635499 DN |
2378 | cfun->gimple_df->in_ssa_p = true; |
2379 | } | |
2380 | ||
7256233c | 2381 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2382 | proceeds in four main phases: |
6de9cd9a | 2383 | |
0bca51f0 DN |
2384 | 1- Compute dominance frontier and immediate dominators, needed to |
2385 | insert PHI nodes and rename the function in dominator tree | |
2386 | order. | |
6de9cd9a | 2387 | |
4d9192b5 | 2388 | 2- Find and mark all the blocks that define variables. |
6de9cd9a | 2389 | |
0bca51f0 | 2390 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2391 | |
0bca51f0 | 2392 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2393 | |
77bfa778 | 2394 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2395 | (walk_dominator_tree). */ |
7256233c | 2396 | |
be55bfe6 TS |
2397 | namespace { |
2398 | ||
2399 | const pass_data pass_data_build_ssa = | |
2400 | { | |
2401 | GIMPLE_PASS, /* type */ | |
2402 | "ssa", /* name */ | |
2403 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
2404 | TV_TREE_SSA_OTHER, /* tv_id */ |
2405 | PROP_cfg, /* properties_required */ | |
2406 | PROP_ssa, /* properties_provided */ | |
2407 | 0, /* properties_destroyed */ | |
2408 | 0, /* todo_flags_start */ | |
3bea341f | 2409 | TODO_remove_unused_locals, /* todo_flags_finish */ |
be55bfe6 TS |
2410 | }; |
2411 | ||
2412 | class pass_build_ssa : public gimple_opt_pass | |
2413 | { | |
2414 | public: | |
2415 | pass_build_ssa (gcc::context *ctxt) | |
2416 | : gimple_opt_pass (pass_data_build_ssa, ctxt) | |
2417 | {} | |
2418 | ||
2419 | /* opt_pass methods: */ | |
2420 | virtual bool gate (function *fun) | |
2421 | { | |
2422 | /* Do nothing for funcions that was produced already in SSA form. */ | |
2423 | return !(fun->curr_properties & PROP_ssa); | |
2424 | } | |
2425 | ||
2426 | virtual unsigned int execute (function *); | |
2427 | ||
2428 | }; // class pass_build_ssa | |
2429 | ||
2430 | unsigned int | |
2431 | pass_build_ssa::execute (function *fun) | |
6de9cd9a | 2432 | { |
0fc555fb | 2433 | bitmap_head *dfs; |
7256233c | 2434 | basic_block bb; |
b8698a0f | 2435 | |
0bca51f0 | 2436 | /* Initialize operand data structures. */ |
be55bfe6 | 2437 | init_ssa_operands (fun); |
6de9cd9a | 2438 | |
38635499 DN |
2439 | /* Initialize internal data needed by the renamer. */ |
2440 | init_ssa_renamer (); | |
2441 | ||
0bca51f0 DN |
2442 | /* Initialize the set of interesting blocks. The callback |
2443 | mark_def_sites will add to this set those blocks that the renamer | |
2444 | should process. */ | |
be55bfe6 | 2445 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (fun)); |
f61e445a | 2446 | bitmap_clear (interesting_blocks); |
6de9cd9a | 2447 | |
af5d3a18 | 2448 | /* Initialize dominance frontier. */ |
be55bfe6 TS |
2449 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (fun)); |
2450 | FOR_EACH_BB_FN (bb, fun) | |
0fc555fb | 2451 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
6de9cd9a | 2452 | |
0bca51f0 DN |
2453 | /* 1- Compute dominance frontiers. */ |
2454 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2455 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2456 | |
0bca51f0 | 2457 | /* 2- Find and mark definition sites. */ |
be55bfe6 | 2458 | mark_def_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr); |
0bca51f0 DN |
2459 | |
2460 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2461 | insert_phi_nodes (dfs); |
6de9cd9a | 2462 | |
0bca51f0 | 2463 | /* 4- Rename all the blocks. */ |
be55bfe6 | 2464 | rewrite_blocks (ENTRY_BLOCK_PTR_FOR_FN (fun), REWRITE_ALL); |
6de9cd9a | 2465 | |
7256233c | 2466 | /* Free allocated memory. */ |
be55bfe6 | 2467 | FOR_EACH_BB_FN (bb, fun) |
0fc555fb | 2468 | bitmap_clear (&dfs[bb->index]); |
7256233c | 2469 | free (dfs); |
6de9cd9a | 2470 | |
b5dcb2b9 JL |
2471 | sbitmap_free (interesting_blocks); |
2472 | ||
38635499 DN |
2473 | fini_ssa_renamer (); |
2474 | ||
70b5e7dc RG |
2475 | /* Try to get rid of all gimplifier generated temporaries by making |
2476 | its SSA names anonymous. This way we can garbage collect them | |
2477 | all after removing unused locals which we do in our TODO. */ | |
46aa019a KV |
2478 | unsigned i; |
2479 | tree name; | |
2480 | ||
2481 | FOR_EACH_SSA_NAME (i, name, cfun) | |
70b5e7dc | 2482 | { |
46aa019a | 2483 | if (SSA_NAME_IS_DEFAULT_DEF (name)) |
70b5e7dc | 2484 | continue; |
46aa019a | 2485 | tree decl = SSA_NAME_VAR (name); |
70b5e7dc | 2486 | if (decl |
8813a647 | 2487 | && VAR_P (decl) |
70b5e7dc | 2488 | && !VAR_DECL_IS_VIRTUAL_OPERAND (decl) |
74fc8b8a RB |
2489 | && DECL_IGNORED_P (decl)) |
2490 | SET_SSA_NAME_VAR_OR_IDENTIFIER (name, DECL_NAME (decl)); | |
70b5e7dc RG |
2491 | } |
2492 | ||
6214d5c7 RB |
2493 | /* Initialize SSA_NAME_POINTS_TO_READONLY_MEMORY. */ |
2494 | tree fnspec = lookup_attribute ("fn spec", | |
2495 | TYPE_ATTRIBUTES (TREE_TYPE (fun->decl))); | |
2496 | if (fnspec) | |
2497 | { | |
2498 | fnspec = TREE_VALUE (TREE_VALUE (fnspec)); | |
2499 | unsigned i = 1; | |
2500 | for (tree arg = DECL_ARGUMENTS (cfun->decl); | |
2501 | arg; arg = DECL_CHAIN (arg), ++i) | |
2502 | { | |
2503 | if (i >= (unsigned) TREE_STRING_LENGTH (fnspec)) | |
2504 | break; | |
2505 | if (TREE_STRING_POINTER (fnspec)[i] == 'R' | |
2506 | || TREE_STRING_POINTER (fnspec)[i] == 'r') | |
2507 | { | |
2508 | tree name = ssa_default_def (fun, arg); | |
2509 | if (name) | |
2510 | SSA_NAME_POINTS_TO_READONLY_MEMORY (name) = 1; | |
2511 | } | |
2512 | } | |
2513 | } | |
2514 | ||
c2924966 | 2515 | return 0; |
6de9cd9a DN |
2516 | } |
2517 | ||
27a4cd48 DM |
2518 | } // anon namespace |
2519 | ||
2520 | gimple_opt_pass * | |
2521 | make_pass_build_ssa (gcc::context *ctxt) | |
2522 | { | |
2523 | return new pass_build_ssa (ctxt); | |
2524 | } | |
2525 | ||
6de9cd9a | 2526 | |
0bca51f0 DN |
2527 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2528 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2529 | |
0bca51f0 | 2530 | static void |
355fe088 TS |
2531 | mark_def_interesting (tree var, gimple *stmt, basic_block bb, |
2532 | bool insert_phi_p) | |
6de9cd9a | 2533 | { |
4ad14919 | 2534 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2535 | set_register_defs (stmt, true); |
0bca51f0 DN |
2536 | |
2537 | if (insert_phi_p) | |
2538 | { | |
726a989a | 2539 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2540 | |
0bca51f0 DN |
2541 | set_def_block (var, bb, is_phi_p); |
2542 | ||
2543 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2544 | site for both itself and all the old names replaced by it. */ | |
2545 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2546 | { | |
2547 | bitmap_iterator bi; | |
2548 | unsigned i; | |
2549 | bitmap set = names_replaced_by (var); | |
2550 | if (set) | |
2551 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2552 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2553 | } | |
2554 | } | |
2555 | } | |
2556 | ||
2557 | ||
2558 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2559 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2560 | nodes. */ |
0bca51f0 DN |
2561 | |
2562 | static inline void | |
355fe088 TS |
2563 | mark_use_interesting (tree var, gimple *stmt, basic_block bb, |
2564 | bool insert_phi_p) | |
0bca51f0 | 2565 | { |
726a989a | 2566 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2567 | |
95dd3097 ZD |
2568 | mark_block_for_update (def_bb); |
2569 | mark_block_for_update (bb); | |
2570 | ||
726a989a | 2571 | if (gimple_code (stmt) == GIMPLE_PHI) |
538dd0b7 | 2572 | mark_phi_for_rewrite (def_bb, as_a <gphi *> (stmt)); |
2ce79879 | 2573 | else |
b5b8b0ac AO |
2574 | { |
2575 | set_rewrite_uses (stmt, true); | |
2576 | ||
2577 | if (is_gimple_debug (stmt)) | |
2578 | return; | |
2579 | } | |
0bca51f0 DN |
2580 | |
2581 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2582 | to BB. Note that we cannot just use the block holding VAR's | |
2583 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2584 | it will have several definitions (itself and all the names that | |
2585 | replace it). */ | |
2586 | if (insert_phi_p) | |
2587 | { | |
526ceb68 | 2588 | def_blocks *db_p = get_def_blocks_for (get_common_info (var)); |
0bca51f0 DN |
2589 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2590 | set_livein_block (var, bb); | |
2591 | } | |
2592 | } | |
2593 | ||
2594 | ||
0bca51f0 | 2595 | /* Do a dominator walk starting at BB processing statements that |
13714310 | 2596 | reference symbols in SSA operands. This is very similar to |
84d65814 | 2597 | mark_def_sites, but the scan handles statements whose operands may |
95dd3097 | 2598 | already be SSA names. |
0bca51f0 | 2599 | |
84d65814 DN |
2600 | If INSERT_PHI_P is true, mark those uses as live in the |
2601 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2602 | algorithm to make PHI pruning decisions. |
2603 | ||
2604 | FIXME. Most of this would be unnecessary if we could associate a | |
2605 | symbol to all the SSA names that reference it. But that | |
2606 | sounds like it would be expensive to maintain. Still, it | |
2607 | would be interesting to see if it makes better sense to do | |
2608 | that. */ | |
0bca51f0 DN |
2609 | |
2610 | static void | |
95dd3097 | 2611 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2612 | { |
2613 | basic_block son; | |
f074ff6c ZD |
2614 | edge e; |
2615 | edge_iterator ei; | |
0bca51f0 | 2616 | |
95dd3097 ZD |
2617 | mark_block_for_update (bb); |
2618 | ||
0bca51f0 | 2619 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2620 | the symbols that we are interested in. */ |
538dd0b7 DM |
2621 | for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); |
2622 | gsi_next (&si)) | |
0bca51f0 | 2623 | { |
538dd0b7 | 2624 | gphi *phi = si.phi (); |
726a989a | 2625 | tree lhs_sym, lhs = gimple_phi_result (phi); |
0bca51f0 | 2626 | |
13714310 | 2627 | if (TREE_CODE (lhs) == SSA_NAME |
a471762f RG |
2628 | && (! virtual_operand_p (lhs) |
2629 | || ! cfun->gimple_df->rename_vops)) | |
f074ff6c | 2630 | continue; |
726a989a | 2631 | |
a471762f | 2632 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
13714310 | 2633 | mark_for_renaming (lhs_sym); |
f074ff6c ZD |
2634 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2635 | ||
2636 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2637 | to process the arguments of the phi nodes of the successor edges of | |
2638 | BB at the end of prepare_block_for_update, however, that turns out | |
2639 | to be significantly more expensive. Doing it here is conservatively | |
2640 | correct -- it may only cause us to believe a value to be live in a | |
2641 | block that also contains its definition, and thus insert a few more | |
2642 | phi nodes for it. */ | |
2643 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2644 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2645 | } |
2646 | ||
2647 | /* Process the statements. */ | |
538dd0b7 DM |
2648 | for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); |
2649 | gsi_next (&si)) | |
0bca51f0 | 2650 | { |
355fe088 | 2651 | gimple *stmt; |
0bca51f0 DN |
2652 | ssa_op_iter i; |
2653 | use_operand_p use_p; | |
2654 | def_operand_p def_p; | |
b8698a0f | 2655 | |
726a989a | 2656 | stmt = gsi_stmt (si); |
0bca51f0 | 2657 | |
13714310 RG |
2658 | if (cfun->gimple_df->rename_vops |
2659 | && gimple_vuse (stmt)) | |
0bca51f0 | 2660 | { |
13714310 | 2661 | tree use = gimple_vuse (stmt); |
0bca51f0 | 2662 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
13714310 RG |
2663 | mark_for_renaming (sym); |
2664 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2665 | } |
2666 | ||
13714310 | 2667 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
0bca51f0 | 2668 | { |
13714310 RG |
2669 | tree use = USE_FROM_PTR (use_p); |
2670 | if (!DECL_P (use)) | |
2671 | continue; | |
2672 | mark_for_renaming (use); | |
2673 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2674 | } | |
2675 | ||
2676 | if (cfun->gimple_df->rename_vops | |
2677 | && gimple_vdef (stmt)) | |
2678 | { | |
2679 | tree def = gimple_vdef (stmt); | |
0bca51f0 | 2680 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
13714310 RG |
2681 | mark_for_renaming (sym); |
2682 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2683 | } | |
2684 | ||
2685 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2686 | { | |
2687 | tree def = DEF_FROM_PTR (def_p); | |
2688 | if (!DECL_P (def)) | |
2689 | continue; | |
2690 | mark_for_renaming (def); | |
2691 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2692 | } |
2693 | } | |
2694 | ||
2695 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2696 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2697 | son; |
2698 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2699 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2700 | } |
2701 | ||
2702 | ||
2703 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2704 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2705 | prepare_names_to_update. */ | |
2706 | ||
2707 | static void | |
95dd3097 | 2708 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2709 | { |
2710 | use_operand_p use_p; | |
2711 | imm_use_iterator iter; | |
2712 | ||
18d08617 RB |
2713 | /* If we rename virtual operands do not update them. */ |
2714 | if (virtual_operand_p (name) | |
2715 | && cfun->gimple_df->rename_vops) | |
2716 | return; | |
2717 | ||
84d65814 DN |
2718 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) |
2719 | { | |
355fe088 | 2720 | gimple *stmt = USE_STMT (use_p); |
726a989a | 2721 | basic_block bb = gimple_bb (stmt); |
84d65814 | 2722 | |
726a989a | 2723 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2724 | { |
f074ff6c | 2725 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
538dd0b7 | 2726 | edge e = gimple_phi_arg_edge (as_a <gphi *> (stmt), ix); |
f074ff6c | 2727 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2728 | } |
2729 | else | |
2730 | { | |
2731 | /* For regular statements, mark this as an interesting use | |
2732 | for NAME. */ | |
95dd3097 | 2733 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2734 | } |
2735 | } | |
0bca51f0 DN |
2736 | } |
2737 | ||
2738 | ||
84d65814 DN |
2739 | /* Helper for prepare_names_to_update. Mark the definition site for |
2740 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2741 | prepare_names_to_update. */ | |
0bca51f0 DN |
2742 | |
2743 | static void | |
95dd3097 | 2744 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2745 | { |
355fe088 | 2746 | gimple *stmt; |
0bca51f0 DN |
2747 | basic_block bb; |
2748 | ||
4ad14919 RG |
2749 | gcc_checking_assert (names_to_release == NULL |
2750 | || !bitmap_bit_p (names_to_release, | |
2751 | SSA_NAME_VERSION (name))); | |
0bca51f0 | 2752 | |
18d08617 RB |
2753 | /* If we rename virtual operands do not update them. */ |
2754 | if (virtual_operand_p (name) | |
2755 | && cfun->gimple_df->rename_vops) | |
2756 | return; | |
2757 | ||
0bca51f0 | 2758 | stmt = SSA_NAME_DEF_STMT (name); |
726a989a | 2759 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2760 | if (bb) |
2761 | { | |
8b1c6fd7 | 2762 | gcc_checking_assert (bb->index < last_basic_block_for_fn (cfun)); |
95dd3097 ZD |
2763 | mark_block_for_update (bb); |
2764 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2765 | } |
2766 | } | |
2767 | ||
2768 | ||
84d65814 | 2769 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2770 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2771 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2772 | |
2773 | static void | |
95dd3097 | 2774 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2775 | { |
dfea6c85 | 2776 | unsigned i = 0; |
0bca51f0 | 2777 | bitmap_iterator bi; |
b6e7e9af | 2778 | sbitmap_iterator sbi; |
0bca51f0 DN |
2779 | |
2780 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2781 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2782 | defining basic block (which most likely doesn't exist). Notice | |
2783 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2784 | want to replace existing instances. */ | |
2785 | if (names_to_release) | |
2786 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
d7c028c0 | 2787 | bitmap_clear_bit (new_ssa_names, i); |
0bca51f0 | 2788 | |
84d65814 DN |
2789 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2790 | names may be considered to be live-in on blocks that contain | |
2791 | definitions for their replacements. */ | |
d4ac4ce2 | 2792 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2793 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2794 | |
0bca51f0 DN |
2795 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2796 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
d4ac4ce2 | 2797 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2798 | { |
2799 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2800 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2801 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2802 | } |
0bca51f0 DN |
2803 | } |
2804 | ||
2805 | ||
2806 | /* Dump all the names replaced by NAME to FILE. */ | |
2807 | ||
2808 | void | |
2809 | dump_names_replaced_by (FILE *file, tree name) | |
2810 | { | |
2811 | unsigned i; | |
2812 | bitmap old_set; | |
2813 | bitmap_iterator bi; | |
2814 | ||
ef6cb4c7 | 2815 | print_generic_expr (file, name); |
0bca51f0 DN |
2816 | fprintf (file, " -> { "); |
2817 | ||
2818 | old_set = names_replaced_by (name); | |
2819 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2820 | { | |
ef6cb4c7 | 2821 | print_generic_expr (file, ssa_name (i)); |
0bca51f0 DN |
2822 | fprintf (file, " "); |
2823 | } | |
2824 | ||
2825 | fprintf (file, "}\n"); | |
2826 | } | |
2827 | ||
2828 | ||
2829 | /* Dump all the names replaced by NAME to stderr. */ | |
2830 | ||
24e47c76 | 2831 | DEBUG_FUNCTION void |
0bca51f0 DN |
2832 | debug_names_replaced_by (tree name) |
2833 | { | |
2834 | dump_names_replaced_by (stderr, name); | |
2835 | } | |
2836 | ||
2837 | ||
84d65814 | 2838 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2839 | |
2840 | void | |
84d65814 | 2841 | dump_update_ssa (FILE *file) |
0bca51f0 | 2842 | { |
dfea6c85 | 2843 | unsigned i = 0; |
0bca51f0 DN |
2844 | bitmap_iterator bi; |
2845 | ||
5006671f | 2846 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
2847 | return; |
2848 | ||
f61e445a | 2849 | if (new_ssa_names && bitmap_first_set_bit (new_ssa_names) >= 0) |
0bca51f0 | 2850 | { |
b6e7e9af KH |
2851 | sbitmap_iterator sbi; |
2852 | ||
0bca51f0 DN |
2853 | fprintf (file, "\nSSA replacement table\n"); |
2854 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2855 | "O_1, ..., O_j\n\n"); | |
2856 | ||
d4ac4ce2 | 2857 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
b6e7e9af | 2858 | dump_names_replaced_by (file, ssa_name (i)); |
0bca51f0 DN |
2859 | } |
2860 | ||
13714310 | 2861 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
0bca51f0 | 2862 | { |
427f99e2 | 2863 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
13714310 | 2864 | dump_decl_set (file, symbols_to_rename_set); |
5006671f | 2865 | fprintf (file, "\n"); |
0bca51f0 DN |
2866 | } |
2867 | ||
0bca51f0 DN |
2868 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2869 | { | |
427f99e2 | 2870 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
0bca51f0 DN |
2871 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2872 | { | |
ef6cb4c7 | 2873 | print_generic_expr (file, ssa_name (i)); |
0bca51f0 DN |
2874 | fprintf (file, " "); |
2875 | } | |
427f99e2 | 2876 | fprintf (file, "\n"); |
0bca51f0 | 2877 | } |
0bca51f0 DN |
2878 | } |
2879 | ||
2880 | ||
84d65814 | 2881 | /* Dump SSA update information to stderr. */ |
0bca51f0 | 2882 | |
24e47c76 | 2883 | DEBUG_FUNCTION void |
84d65814 | 2884 | debug_update_ssa (void) |
0bca51f0 | 2885 | { |
84d65814 | 2886 | dump_update_ssa (stderr); |
0bca51f0 DN |
2887 | } |
2888 | ||
2889 | ||
2890 | /* Initialize data structures used for incremental SSA updates. */ | |
2891 | ||
2892 | static void | |
5006671f | 2893 | init_update_ssa (struct function *fn) |
0bca51f0 | 2894 | { |
84d65814 | 2895 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2896 | add_new_name_mapping are typically done after creating new SSA |
2897 | names, so we'll need to reallocate these arrays. */ | |
2898 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2899 | bitmap_clear (old_ssa_names); |
0bca51f0 DN |
2900 | |
2901 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2902 | bitmap_clear (new_ssa_names); |
0bca51f0 | 2903 | |
891f2df6 RG |
2904 | bitmap_obstack_initialize (&update_ssa_obstack); |
2905 | ||
0bca51f0 | 2906 | names_to_release = NULL; |
5006671f | 2907 | update_ssa_initialized_fn = fn; |
0bca51f0 DN |
2908 | } |
2909 | ||
2910 | ||
2911 | /* Deallocate data structures used for incremental SSA updates. */ | |
2912 | ||
84d65814 | 2913 | void |
0bca51f0 DN |
2914 | delete_update_ssa (void) |
2915 | { | |
2916 | unsigned i; | |
2917 | bitmap_iterator bi; | |
2918 | ||
2919 | sbitmap_free (old_ssa_names); | |
2920 | old_ssa_names = NULL; | |
2921 | ||
2922 | sbitmap_free (new_ssa_names); | |
2923 | new_ssa_names = NULL; | |
2924 | ||
13714310 RG |
2925 | BITMAP_FREE (symbols_to_rename_set); |
2926 | symbols_to_rename_set = NULL; | |
9771b263 | 2927 | symbols_to_rename.release (); |
0bca51f0 DN |
2928 | |
2929 | if (names_to_release) | |
2930 | { | |
2931 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2932 | release_ssa_name (ssa_name (i)); | |
2933 | BITMAP_FREE (names_to_release); | |
2934 | } | |
2935 | ||
95dd3097 | 2936 | clear_ssa_name_info (); |
38635499 DN |
2937 | |
2938 | fini_ssa_renamer (); | |
2939 | ||
2940 | if (blocks_with_phis_to_rewrite) | |
2941 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2942 | { | |
538dd0b7 | 2943 | vec<gphi *> phis = phis_to_rewrite[i]; |
9771b263 DN |
2944 | phis.release (); |
2945 | phis_to_rewrite[i].create (0); | |
38635499 DN |
2946 | } |
2947 | ||
2948 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2949 | BITMAP_FREE (blocks_to_update); | |
891f2df6 | 2950 | |
5006671f | 2951 | update_ssa_initialized_fn = NULL; |
0bca51f0 DN |
2952 | } |
2953 | ||
2954 | ||
2955 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
45db3141 RG |
2956 | operand pointed to by DEF_P with the newly created name. If DEF_P |
2957 | is NULL then STMT should be a GIMPLE assignment. | |
2958 | Return the new name and register the replacement mapping <NEW, OLD> in | |
0bca51f0 DN |
2959 | update_ssa's tables. */ |
2960 | ||
2961 | tree | |
355fe088 | 2962 | create_new_def_for (tree old_name, gimple *stmt, def_operand_p def) |
0bca51f0 | 2963 | { |
45db3141 | 2964 | tree new_name; |
0bca51f0 | 2965 | |
45db3141 RG |
2966 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
2967 | ||
2968 | if (!update_ssa_initialized_fn) | |
2969 | init_update_ssa (cfun); | |
2970 | ||
2971 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2972 | ||
2973 | new_name = duplicate_ssa_name (old_name, stmt); | |
2974 | if (def) | |
2975 | SET_DEF (def, new_name); | |
2976 | else | |
2977 | gimple_assign_set_lhs (stmt, new_name); | |
0bca51f0 | 2978 | |
726a989a | 2979 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 | 2980 | { |
726a989a | 2981 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2982 | |
2983 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
31ff2426 | 2984 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
0bca51f0 DN |
2985 | } |
2986 | ||
45db3141 | 2987 | add_new_name_mapping (new_name, old_name); |
0bca51f0 DN |
2988 | |
2989 | /* For the benefit of passes that will be updating the SSA form on | |
2990 | their own, set the current reaching definition of OLD_NAME to be | |
2991 | NEW_NAME. */ | |
8812aab1 | 2992 | get_ssa_name_ann (old_name)->info.current_def = new_name; |
0bca51f0 | 2993 | |
45db3141 | 2994 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
0bca51f0 | 2995 | |
45db3141 | 2996 | return new_name; |
0bca51f0 DN |
2997 | } |
2998 | ||
2999 | ||
525174a2 | 3000 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
0bca51f0 DN |
3001 | |
3002 | void | |
525174a2 | 3003 | mark_virtual_operands_for_renaming (struct function *fn) |
0bca51f0 | 3004 | { |
525174a2 RG |
3005 | fn->gimple_df->ssa_renaming_needed = 1; |
3006 | fn->gimple_df->rename_vops = 1; | |
0bca51f0 DN |
3007 | } |
3008 | ||
3d9c733e AM |
3009 | /* Replace all uses of NAME by underlying variable and mark it |
3010 | for renaming. This assumes the defining statement of NAME is | |
3011 | going to be removed. */ | |
3012 | ||
3013 | void | |
3014 | mark_virtual_operand_for_renaming (tree name) | |
3015 | { | |
3016 | tree name_var = SSA_NAME_VAR (name); | |
3017 | bool used = false; | |
3018 | imm_use_iterator iter; | |
3019 | use_operand_p use_p; | |
355fe088 | 3020 | gimple *stmt; |
3d9c733e AM |
3021 | |
3022 | gcc_assert (VAR_DECL_IS_VIRTUAL_OPERAND (name_var)); | |
3023 | FOR_EACH_IMM_USE_STMT (stmt, iter, name) | |
3024 | { | |
3025 | FOR_EACH_IMM_USE_ON_STMT (use_p, iter) | |
3026 | SET_USE (use_p, name_var); | |
3027 | used = true; | |
3028 | } | |
3029 | if (used) | |
3030 | mark_virtual_operands_for_renaming (cfun); | |
3031 | } | |
3032 | ||
3033 | /* Replace all uses of the virtual PHI result by its underlying variable | |
3034 | and mark it for renaming. This assumes the PHI node is going to be | |
3035 | removed. */ | |
3036 | ||
3037 | void | |
538dd0b7 | 3038 | mark_virtual_phi_result_for_renaming (gphi *phi) |
3d9c733e AM |
3039 | { |
3040 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3041 | { | |
3042 | fprintf (dump_file, "Marking result for renaming : "); | |
3043 | print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
3044 | fprintf (dump_file, "\n"); | |
3045 | } | |
3046 | ||
3047 | mark_virtual_operand_for_renaming (gimple_phi_result (phi)); | |
3048 | } | |
0bca51f0 | 3049 | |
5006671f RG |
3050 | /* Return true if there is any work to be done by update_ssa |
3051 | for function FN. */ | |
0bca51f0 DN |
3052 | |
3053 | bool | |
5006671f | 3054 | need_ssa_update_p (struct function *fn) |
0bca51f0 | 3055 | { |
5006671f RG |
3056 | gcc_assert (fn != NULL); |
3057 | return (update_ssa_initialized_fn == fn | |
13714310 | 3058 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
0bca51f0 DN |
3059 | } |
3060 | ||
0bca51f0 DN |
3061 | /* Return true if name N has been registered in the replacement table. */ |
3062 | ||
3063 | bool | |
726a989a | 3064 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 | 3065 | { |
5006671f | 3066 | if (!update_ssa_initialized_fn) |
0bca51f0 DN |
3067 | return false; |
3068 | ||
5006671f RG |
3069 | gcc_assert (update_ssa_initialized_fn == cfun); |
3070 | ||
3071 | return is_new_name (n) || is_old_name (n); | |
0bca51f0 DN |
3072 | } |
3073 | ||
3074 | ||
0bca51f0 DN |
3075 | /* Mark NAME to be released after update_ssa has finished. */ |
3076 | ||
3077 | void | |
3078 | release_ssa_name_after_update_ssa (tree name) | |
3079 | { | |
5006671f | 3080 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
0bca51f0 DN |
3081 | |
3082 | if (names_to_release == NULL) | |
3083 | names_to_release = BITMAP_ALLOC (NULL); | |
3084 | ||
3085 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
3086 | } | |
3087 | ||
3088 | ||
3089 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
3090 | frontier information. BLOCKS is the set of blocks to be updated. | |
3091 | ||
3092 | This is slightly different than the regular PHI insertion | |
3093 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
3094 | real names (i.e., GIMPLE registers) are inserted: | |
b8698a0f | 3095 | |
0bca51f0 DN |
3096 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
3097 | nodes inside the region affected by the block that defines VAR | |
3098 | and the blocks that define all its replacements. All these | |
84d65814 | 3099 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
3100 | |
3101 | First, we compute the entry point to the region (ENTRY). This is | |
3102 | given by the nearest common dominator to all the definition | |
3103 | blocks. When computing the iterated dominance frontier (IDF), any | |
3104 | block not strictly dominated by ENTRY is ignored. | |
3105 | ||
3106 | We then call the standard PHI insertion algorithm with the pruned | |
3107 | IDF. | |
3108 | ||
3109 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
3110 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
3111 | ||
3112 | static void | |
0fc555fb | 3113 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
0bca51f0 DN |
3114 | unsigned update_flags) |
3115 | { | |
3116 | basic_block entry; | |
526ceb68 | 3117 | def_blocks *db; |
0bca51f0 DN |
3118 | bitmap idf, pruned_idf; |
3119 | bitmap_iterator bi; | |
3120 | unsigned i; | |
3121 | ||
0bca51f0 | 3122 | if (TREE_CODE (var) == SSA_NAME) |
77a74ed7 | 3123 | gcc_checking_assert (is_old_name (var)); |
0bca51f0 | 3124 | else |
13714310 | 3125 | gcc_checking_assert (marked_for_renaming (var)); |
0bca51f0 DN |
3126 | |
3127 | /* Get all the definition sites for VAR. */ | |
3128 | db = find_def_blocks_for (var); | |
3129 | ||
3130 | /* No need to do anything if there were no definitions to VAR. */ | |
3131 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3132 | return; | |
3133 | ||
3134 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 3135 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
3136 | pruned_idf = BITMAP_ALLOC (NULL); |
3137 | ||
3138 | if (TREE_CODE (var) == SSA_NAME) | |
3139 | { | |
3140 | if (update_flags == TODO_update_ssa) | |
3141 | { | |
3142 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3143 | only interested in IDF blocks dominated by the nearest | |
3144 | common dominator of all the definition blocks. */ | |
3145 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3146 | db->def_blocks); | |
fefa31b5 | 3147 | if (entry != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
0bca51f0 | 3148 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) |
06e28de2 DM |
3149 | if (BASIC_BLOCK_FOR_FN (cfun, i) != entry |
3150 | && dominated_by_p (CDI_DOMINATORS, | |
3151 | BASIC_BLOCK_FOR_FN (cfun, i), entry)) | |
0bca51f0 DN |
3152 | bitmap_set_bit (pruned_idf, i); |
3153 | } | |
3154 | else | |
3155 | { | |
3156 | /* Otherwise, do not prune the IDF for VAR. */ | |
4ad14919 | 3157 | gcc_checking_assert (update_flags == TODO_update_ssa_full_phi); |
0bca51f0 DN |
3158 | bitmap_copy (pruned_idf, idf); |
3159 | } | |
3160 | } | |
3161 | else | |
3162 | { | |
3163 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3164 | for the first time, so we need to compute the full IDF for | |
3165 | it. */ | |
3166 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
3167 | } |
3168 | ||
3169 | if (!bitmap_empty_p (pruned_idf)) | |
3170 | { | |
3171 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3172 | are included in the region to be updated. The feeding blocks | |
3173 | are important to guarantee that the PHI arguments are renamed | |
3174 | properly. */ | |
38635499 DN |
3175 | |
3176 | /* FIXME, this is not needed if we are updating symbols. We are | |
3177 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
3178 | bitmap_ior_into (blocks, pruned_idf); |
3179 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3180 | { | |
3181 | edge e; | |
3182 | edge_iterator ei; | |
06e28de2 | 3183 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); |
0bca51f0 DN |
3184 | |
3185 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3186 | if (e->src->index >= 0) | |
3187 | bitmap_set_bit (blocks, e->src->index); | |
3188 | } | |
3189 | ||
3190 | insert_phi_nodes_for (var, pruned_idf, true); | |
3191 | } | |
3192 | ||
3193 | BITMAP_FREE (pruned_idf); | |
3194 | BITMAP_FREE (idf); | |
3195 | } | |
3196 | ||
fa5556de RB |
3197 | /* Sort symbols_to_rename after their DECL_UID. */ |
3198 | ||
3199 | static int | |
3200 | insert_updated_phi_nodes_compare_uids (const void *a, const void *b) | |
3201 | { | |
3202 | const_tree syma = *(const const_tree *)a; | |
3203 | const_tree symb = *(const const_tree *)b; | |
3204 | if (DECL_UID (syma) == DECL_UID (symb)) | |
3205 | return 0; | |
3206 | return DECL_UID (syma) < DECL_UID (symb) ? -1 : 1; | |
3207 | } | |
0bca51f0 DN |
3208 | |
3209 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3210 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3211 | ||
3212 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3213 | NEW_SSA_NAMES are all re-written to be reached by the | |
3214 | appropriate definition from NEW_SSA_NAMES. | |
3215 | ||
3216 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3217 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3218 | ||
3219 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
45db3141 | 3220 | calling create_new_def_for to create new defs for names that the |
0bca51f0 DN |
3221 | caller wants to replace. |
3222 | ||
45db3141 RG |
3223 | The caller cretaes the new names to be inserted and the names that need |
3224 | to be replaced by calling create_new_def_for for each old definition | |
3225 | to be replaced. Note that the function assumes that the | |
3226 | new defining statement has already been inserted in the IL. | |
0bca51f0 DN |
3227 | |
3228 | For instance, given the following code: | |
3229 | ||
3230 | 1 L0: | |
3231 | 2 x_1 = PHI (0, x_5) | |
3232 | 3 if (x_1 < 10) | |
3233 | 4 if (x_1 > 7) | |
3234 | 5 y_2 = 0 | |
3235 | 6 else | |
3236 | 7 y_3 = x_1 + x_7 | |
3237 | 8 endif | |
3238 | 9 x_5 = x_1 + 1 | |
3239 | 10 goto L0; | |
3240 | 11 endif | |
3241 | ||
3242 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3243 | ||
3244 | 1 L0: | |
3245 | 2 x_1 = PHI (0, x_5) | |
3246 | 3 if (x_1 < 10) | |
3247 | 4 x_10 = ... | |
3248 | 5 if (x_1 > 7) | |
3249 | 6 y_2 = 0 | |
3250 | 7 else | |
3251 | 8 x_11 = ... | |
3252 | 9 y_3 = x_1 + x_7 | |
3253 | 10 endif | |
3254 | 11 x_5 = x_1 + 1 | |
3255 | 12 goto L0; | |
3256 | 13 endif | |
3257 | ||
3258 | We want to replace all the uses of x_1 with the new definitions of | |
3259 | x_10 and x_11. Note that the only uses that should be replaced are | |
3260 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3261 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3262 | renaming). | |
3263 | ||
3264 | Additionally, we may need to insert a PHI node at line 11 because | |
3265 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3266 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3267 | nodes is optional. They are not strictly necessary to preserve the | |
3268 | SSA form, and depending on what the caller inserted, they may not | |
3269 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3270 | aspects of how update_ssa operates, see the documentation for | |
3271 | TODO_update_ssa*. */ | |
3272 | ||
3273 | void | |
3274 | update_ssa (unsigned update_flags) | |
3275 | { | |
0bca51f0 DN |
3276 | basic_block bb, start_bb; |
3277 | bitmap_iterator bi; | |
dfea6c85 | 3278 | unsigned i = 0; |
0bca51f0 | 3279 | bool insert_phi_p; |
b6e7e9af | 3280 | sbitmap_iterator sbi; |
13714310 | 3281 | tree sym; |
0bca51f0 | 3282 | |
580b2c2e SB |
3283 | /* Only one update flag should be set. */ |
3284 | gcc_assert (update_flags == TODO_update_ssa | |
3285 | || update_flags == TODO_update_ssa_no_phi | |
3286 | || update_flags == TODO_update_ssa_full_phi | |
3287 | || update_flags == TODO_update_ssa_only_virtuals); | |
3288 | ||
5006671f | 3289 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
3290 | return; |
3291 | ||
b2b29377 MM |
3292 | if (flag_checking) |
3293 | { | |
3294 | timevar_push (TV_TREE_STMT_VERIFY); | |
90ad8d00 | 3295 | |
b2b29377 | 3296 | bool err = false; |
90ad8d00 | 3297 | |
b2b29377 | 3298 | FOR_EACH_BB_FN (bb, cfun) |
90ad8d00 | 3299 | { |
b2b29377 MM |
3300 | gimple_stmt_iterator gsi; |
3301 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
90ad8d00 | 3302 | { |
b2b29377 | 3303 | gimple *stmt = gsi_stmt (gsi); |
90ad8d00 | 3304 | |
b2b29377 MM |
3305 | ssa_op_iter i; |
3306 | use_operand_p use_p; | |
3307 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) | |
90ad8d00 | 3308 | { |
b2b29377 MM |
3309 | tree use = USE_FROM_PTR (use_p); |
3310 | if (TREE_CODE (use) != SSA_NAME) | |
3311 | continue; | |
3312 | ||
3313 | if (SSA_NAME_IN_FREE_LIST (use)) | |
3314 | { | |
3315 | error ("statement uses released SSA name:"); | |
3316 | debug_gimple_stmt (stmt); | |
3317 | fprintf (stderr, "The use of "); | |
ef6cb4c7 | 3318 | print_generic_expr (stderr, use); |
b2b29377 MM |
3319 | fprintf (stderr," should have been replaced\n"); |
3320 | err = true; | |
3321 | } | |
90ad8d00 TV |
3322 | } |
3323 | } | |
3324 | } | |
90ad8d00 | 3325 | |
b2b29377 MM |
3326 | if (err) |
3327 | internal_error ("cannot update SSA form"); | |
90ad8d00 | 3328 | |
b2b29377 MM |
3329 | timevar_pop (TV_TREE_STMT_VERIFY); |
3330 | } | |
90ad8d00 | 3331 | |
0bca51f0 DN |
3332 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
3333 | ||
427f99e2 MJ |
3334 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3335 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3336 | ||
5006671f RG |
3337 | if (!update_ssa_initialized_fn) |
3338 | init_update_ssa (cfun); | |
580b2c2e SB |
3339 | else if (update_flags == TODO_update_ssa_only_virtuals) |
3340 | { | |
3341 | /* If we only need to update virtuals, remove all the mappings for | |
3342 | real names before proceeding. The caller is responsible for | |
3343 | having dealt with the name mappings before calling update_ssa. */ | |
f61e445a LC |
3344 | bitmap_clear (old_ssa_names); |
3345 | bitmap_clear (new_ssa_names); | |
580b2c2e SB |
3346 | } |
3347 | ||
5006671f RG |
3348 | gcc_assert (update_ssa_initialized_fn == cfun); |
3349 | ||
2ce79879 | 3350 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
9771b263 | 3351 | if (!phis_to_rewrite.exists ()) |
8b1c6fd7 | 3352 | phis_to_rewrite.create (last_basic_block_for_fn (cfun) + 1); |
95dd3097 | 3353 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3354 | |
0bca51f0 DN |
3355 | /* Ensure that the dominance information is up-to-date. */ |
3356 | calculate_dominance_info (CDI_DOMINATORS); | |
3357 | ||
84d65814 | 3358 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 | 3359 | |
84d65814 DN |
3360 | /* If there are names defined in the replacement table, prepare |
3361 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3362 | OLD_SSA_NAMES. */ | |
f61e445a | 3363 | if (bitmap_first_set_bit (new_ssa_names) >= 0) |
84d65814 | 3364 | { |
f0251020 RB |
3365 | statistics_counter_event (cfun, "Incremental SSA update", 1); |
3366 | ||
95dd3097 | 3367 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3368 | |
3369 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3370 | removal, and there are no symbols to rename, then there's | |
3371 | nothing else to do. */ | |
f61e445a | 3372 | if (bitmap_first_set_bit (new_ssa_names) < 0 |
13714310 | 3373 | && !cfun->gimple_df->ssa_renaming_needed) |
84d65814 DN |
3374 | goto done; |
3375 | } | |
3376 | ||
3377 | /* Next, determine the block at which to start the renaming process. */ | |
13714310 | 3378 | if (cfun->gimple_df->ssa_renaming_needed) |
84d65814 | 3379 | { |
f0251020 RB |
3380 | statistics_counter_event (cfun, "Symbol to SSA rewrite", 1); |
3381 | ||
b4e209fd RG |
3382 | /* If we rename bare symbols initialize the mapping to |
3383 | auxiliar info we need to keep track of. */ | |
c203e8a7 | 3384 | var_infos = new hash_table<var_info_hasher> (47); |
b4e209fd | 3385 | |
84d65814 DN |
3386 | /* If we have to rename some symbols from scratch, we need to |
3387 | start the process at the root of the CFG. FIXME, it should | |
3388 | be possible to determine the nearest block that had a | |
3389 | definition for each of the symbols that are marked for | |
3390 | updating. For now this seems more work than it's worth. */ | |
fefa31b5 | 3391 | start_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
84d65814 | 3392 | |
38635499 | 3393 | /* Traverse the CFG looking for existing definitions and uses of |
13714310 | 3394 | symbols in SSA operands. Mark interesting blocks and |
38635499 DN |
3395 | statements and set local live-in information for the PHI |
3396 | placement heuristics. */ | |
95dd3097 | 3397 | prepare_block_for_update (start_bb, insert_phi_p); |
343c5d46 | 3398 | |
46aa019a KV |
3399 | tree name; |
3400 | ||
b2b29377 | 3401 | if (flag_checking) |
46aa019a | 3402 | FOR_EACH_SSA_NAME (i, name, cfun) |
b2b29377 | 3403 | { |
46aa019a | 3404 | if (virtual_operand_p (name)) |
b2b29377 MM |
3405 | continue; |
3406 | ||
3407 | /* For all but virtual operands, which do not have SSA names | |
3408 | with overlapping life ranges, ensure that symbols marked | |
3409 | for renaming do not have existing SSA names associated with | |
3410 | them as we do not re-write them out-of-SSA before going | |
3411 | into SSA for the remaining symbol uses. */ | |
3412 | if (marked_for_renaming (SSA_NAME_VAR (name))) | |
3413 | { | |
3414 | fprintf (stderr, "Existing SSA name for symbol marked for " | |
3415 | "renaming: "); | |
3416 | print_generic_expr (stderr, name, TDF_SLIM); | |
3417 | fprintf (stderr, "\n"); | |
3418 | internal_error ("SSA corruption"); | |
3419 | } | |
3420 | } | |
0bca51f0 DN |
3421 | } |
3422 | else | |
84d65814 DN |
3423 | { |
3424 | /* Otherwise, the entry block to the region is the nearest | |
3425 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3426 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3427 | blocks_to_update); | |
84d65814 | 3428 | } |
0bca51f0 DN |
3429 | |
3430 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3431 | of every block, creating new definitions for names in OLD_SSA_NAMES |
13714310 | 3432 | and for symbols found. */ |
0bca51f0 DN |
3433 | if (insert_phi_p) |
3434 | { | |
0fc555fb | 3435 | bitmap_head *dfs; |
9caf90a8 KH |
3436 | |
3437 | /* If the caller requested PHI nodes to be added, compute | |
3438 | dominance frontiers. */ | |
8b1c6fd7 | 3439 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
11cd3bed | 3440 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3441 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
9caf90a8 KH |
3442 | compute_dominance_frontiers (dfs); |
3443 | ||
f61e445a | 3444 | if (bitmap_first_set_bit (old_ssa_names) >= 0) |
0bca51f0 | 3445 | { |
b6e7e9af KH |
3446 | sbitmap_iterator sbi; |
3447 | ||
84d65814 DN |
3448 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3449 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3450 | will grow while we are traversing it (but it will not | |
3451 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3452 | for traversal. */ | |
7ba9e72d | 3453 | auto_sbitmap tmp (SBITMAP_SIZE (old_ssa_names)); |
f61e445a | 3454 | bitmap_copy (tmp, old_ssa_names); |
d4ac4ce2 | 3455 | EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi) |
95dd3097 | 3456 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3457 | update_flags); |
0bca51f0 DN |
3458 | } |
3459 | ||
fa5556de | 3460 | symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids); |
9771b263 | 3461 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
13714310 | 3462 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, |
38635499 | 3463 | update_flags); |
0bca51f0 | 3464 | |
11cd3bed | 3465 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3466 | bitmap_clear (&dfs[bb->index]); |
9caf90a8 KH |
3467 | free (dfs); |
3468 | ||
0bca51f0 DN |
3469 | /* Insertion of PHI nodes may have added blocks to the region. |
3470 | We need to re-compute START_BB to include the newly added | |
3471 | blocks. */ | |
fefa31b5 | 3472 | if (start_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
95dd3097 ZD |
3473 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3474 | blocks_to_update); | |
0bca51f0 DN |
3475 | } |
3476 | ||
3477 | /* Reset the current definition for name and symbol before renaming | |
3478 | the sub-graph. */ | |
d4ac4ce2 | 3479 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
8812aab1 | 3480 | get_ssa_name_ann (ssa_name (i))->info.current_def = NULL_TREE; |
0bca51f0 | 3481 | |
9771b263 | 3482 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
8812aab1 | 3483 | get_var_info (sym)->info.current_def = NULL_TREE; |
0bca51f0 DN |
3484 | |
3485 | /* Now start the renaming process at START_BB. */ | |
8b1c6fd7 | 3486 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
f61e445a | 3487 | bitmap_clear (interesting_blocks); |
95dd3097 | 3488 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
d7c028c0 | 3489 | bitmap_set_bit (interesting_blocks, i); |
0bca51f0 | 3490 | |
ccf5c864 | 3491 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
0bca51f0 | 3492 | |
ccf5c864 | 3493 | sbitmap_free (interesting_blocks); |
0bca51f0 DN |
3494 | |
3495 | /* Debugging dumps. */ | |
3496 | if (dump_file) | |
3497 | { | |
3498 | int c; | |
3499 | unsigned i; | |
3500 | ||
84d65814 | 3501 | dump_update_ssa (dump_file); |
0bca51f0 | 3502 | |
427f99e2 | 3503 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
0bca51f0 DN |
3504 | start_bb->index); |
3505 | ||
3506 | c = 0; | |
95dd3097 | 3507 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 | 3508 | c++; |
8b1c6fd7 DM |
3509 | fprintf (dump_file, "Number of blocks in CFG: %d\n", |
3510 | last_basic_block_for_fn (cfun)); | |
427f99e2 | 3511 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
8b1c6fd7 | 3512 | c, PERCENT (c, last_basic_block_for_fn (cfun))); |
0bca51f0 DN |
3513 | |
3514 | if (dump_flags & TDF_DETAILS) | |
3515 | { | |
0eb09f31 | 3516 | fprintf (dump_file, "Affected blocks:"); |
95dd3097 | 3517 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0eb09f31 | 3518 | fprintf (dump_file, " %u", i); |
0bca51f0 DN |
3519 | fprintf (dump_file, "\n"); |
3520 | } | |
3521 | ||
3522 | fprintf (dump_file, "\n\n"); | |
3523 | } | |
3524 | ||
3525 | /* Free allocated memory. */ | |
84d65814 | 3526 | done: |
0bca51f0 DN |
3527 | delete_update_ssa (); |
3528 | ||
3529 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3530 | } |