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6de9cd9a | 1 | /* Rewrite a program in Normal form into SSA. |
5624e564 | 2 | Copyright (C) 2001-2015 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 DN |
39 | #include "domwalk.h" |
40 | ||
1fe37220 | 41 | #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y)) |
726a989a | 42 | |
6de9cd9a DN |
43 | /* This file builds the SSA form for a function as described in: |
44 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
45 | Computing Static Single Assignment Form and the Control Dependence | |
46 | Graph. ACM Transactions on Programming Languages and Systems, | |
47 | 13(4):451-490, October 1991. */ | |
48 | ||
6de9cd9a DN |
49 | /* Structure to map a variable VAR to the set of blocks that contain |
50 | definitions for VAR. */ | |
526ceb68 | 51 | struct def_blocks |
6de9cd9a | 52 | { |
6de9cd9a DN |
53 | /* Blocks that contain definitions of VAR. Bit I will be set if the |
54 | Ith block contains a definition of VAR. */ | |
55 | bitmap def_blocks; | |
56 | ||
7256233c | 57 | /* Blocks that contain a PHI node for VAR. */ |
5f240ec4 ZD |
58 | bitmap phi_blocks; |
59 | ||
6de9cd9a DN |
60 | /* Blocks where VAR is live-on-entry. Similar semantics as |
61 | DEF_BLOCKS. */ | |
62 | bitmap livein_blocks; | |
63 | }; | |
64 | ||
9fae925b | 65 | /* Stack of trees used to restore the global currdefs to its original |
0bca51f0 DN |
66 | state after completing rewriting of a block and its dominator |
67 | children. Its elements have the following properties: | |
9fae925b | 68 | |
38635499 DN |
69 | - An SSA_NAME (N) indicates that the current definition of the |
70 | underlying variable should be set to the given SSA_NAME. If the | |
71 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
72 | next slot in the stack must be a _DECL node (SYM). In this case, | |
73 | the name N in the previous slot is the current reaching | |
74 | definition for SYM. | |
9fae925b | 75 | |
0bca51f0 DN |
76 | - A _DECL node indicates that the underlying variable has no |
77 | current definition. | |
7256233c | 78 | |
38635499 | 79 | - A NULL node at the top entry is used to mark the last slot |
0bca51f0 | 80 | associated with the current block. */ |
9771b263 | 81 | static vec<tree> block_defs_stack; |
3a2e4b46 | 82 | |
726a989a | 83 | |
0bca51f0 DN |
84 | /* Set of existing SSA names being replaced by update_ssa. */ |
85 | static sbitmap old_ssa_names; | |
86 | ||
87 | /* Set of new SSA names being added by update_ssa. Note that both | |
88 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
89 | the operations done on them are presence tests. */ | |
90 | static sbitmap new_ssa_names; | |
91 | ||
16876bdc | 92 | static sbitmap interesting_blocks; |
726a989a | 93 | |
0bca51f0 DN |
94 | /* Set of SSA names that have been marked to be released after they |
95 | were registered in the replacement table. They will be finally | |
96 | released after we finish updating the SSA web. */ | |
d2e2feaa | 97 | bitmap names_to_release; |
0bca51f0 | 98 | |
9771b263 | 99 | /* vec of vec of PHIs to rewrite in a basic block. Element I corresponds |
580b2c2e SB |
100 | the to basic block with index I. Allocated once per compilation, *not* |
101 | released between different functions. */ | |
538dd0b7 | 102 | static vec< vec<gphi *> > phis_to_rewrite; |
2ce79879 ZD |
103 | |
104 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
105 | static bitmap blocks_with_phis_to_rewrite; |
106 | ||
0bca51f0 | 107 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
45db3141 RG |
108 | to grow as the callers to create_new_def_for will create new names on |
109 | the fly. | |
110 | FIXME. Currently set to 1/3 to avoid frequent reallocations but still | |
111 | need to find a reasonable growth strategy. */ | |
0bca51f0 DN |
112 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) |
113 | ||
0bca51f0 | 114 | |
5006671f | 115 | /* The function the SSA updating data structures have been initialized for. |
45db3141 | 116 | NULL if they need to be initialized by create_new_def_for. */ |
5006671f | 117 | static struct function *update_ssa_initialized_fn = NULL; |
0bca51f0 | 118 | |
6de9cd9a DN |
119 | /* Global data to attach to the main dominator walk structure. */ |
120 | struct mark_def_sites_global_data | |
121 | { | |
0bca51f0 DN |
122 | /* This bitmap contains the variables which are set before they |
123 | are used in a basic block. */ | |
7d793e36 | 124 | bitmap kills; |
6de9cd9a DN |
125 | }; |
126 | ||
80560f95 AM |
127 | /* It is advantageous to avoid things like life analysis for variables which |
128 | do not need PHI nodes. This enum describes whether or not a particular | |
129 | variable may need a PHI node. */ | |
130 | ||
131 | enum need_phi_state { | |
132 | /* This is the default. If we are still in this state after finding | |
133 | all the definition and use sites, then we will assume the variable | |
134 | needs PHI nodes. This is probably an overly conservative assumption. */ | |
135 | NEED_PHI_STATE_UNKNOWN, | |
136 | ||
137 | /* This state indicates that we have seen one or more sets of the | |
138 | variable in a single basic block and that the sets dominate all | |
139 | uses seen so far. If after finding all definition and use sites | |
140 | we are still in this state, then the variable does not need any | |
141 | PHI nodes. */ | |
142 | NEED_PHI_STATE_NO, | |
143 | ||
144 | /* This state indicates that we have either seen multiple definitions of | |
145 | the variable in multiple blocks, or that we encountered a use in a | |
146 | block that was not dominated by the block containing the set(s) of | |
147 | this variable. This variable is assumed to need PHI nodes. */ | |
148 | NEED_PHI_STATE_MAYBE | |
149 | }; | |
150 | ||
8812aab1 | 151 | /* Information stored for both SSA names and decls. */ |
526ceb68 | 152 | struct common_info |
b4e209fd | 153 | { |
b4e209fd RG |
154 | /* This field indicates whether or not the variable may need PHI nodes. |
155 | See the enum's definition for more detailed information about the | |
156 | states. */ | |
157 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
158 | ||
8812aab1 | 159 | /* The current reaching definition replacing this var. */ |
b4e209fd RG |
160 | tree current_def; |
161 | ||
8812aab1 | 162 | /* Definitions for this var. */ |
526ceb68 | 163 | struct def_blocks def_blocks; |
b4e209fd RG |
164 | }; |
165 | ||
8812aab1 | 166 | /* Information stored for decls. */ |
526ceb68 | 167 | struct var_info |
8812aab1 RG |
168 | { |
169 | /* The variable. */ | |
170 | tree var; | |
171 | ||
172 | /* Information stored for both SSA names and decls. */ | |
526ceb68 | 173 | common_info info; |
8812aab1 RG |
174 | }; |
175 | ||
b4e209fd | 176 | |
bf190e8d LC |
177 | /* VAR_INFOS hashtable helpers. */ |
178 | ||
526ceb68 | 179 | struct var_info_hasher : free_ptr_hash <var_info> |
bf190e8d | 180 | { |
84baa4b9 TS |
181 | static inline hashval_t hash (const value_type &); |
182 | static inline bool equal (const value_type &, const compare_type &); | |
bf190e8d LC |
183 | }; |
184 | ||
185 | inline hashval_t | |
84baa4b9 | 186 | var_info_hasher::hash (const value_type &p) |
bf190e8d LC |
187 | { |
188 | return DECL_UID (p->var); | |
189 | } | |
190 | ||
191 | inline bool | |
84baa4b9 | 192 | var_info_hasher::equal (const value_type &p1, const compare_type &p2) |
bf190e8d LC |
193 | { |
194 | return p1->var == p2->var; | |
195 | } | |
196 | ||
197 | ||
b4e209fd RG |
198 | /* Each entry in VAR_INFOS contains an element of type STRUCT |
199 | VAR_INFO_D. */ | |
c203e8a7 | 200 | static hash_table<var_info_hasher> *var_infos; |
b4e209fd RG |
201 | |
202 | ||
0bca51f0 | 203 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
204 | struct ssa_name_info |
205 | { | |
891f2df6 RG |
206 | /* Age of this record (so that info_for_ssa_name table can be cleared |
207 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
208 | are assumed to be null. */ | |
209 | unsigned age; | |
95dd3097 | 210 | |
891f2df6 RG |
211 | /* Replacement mappings, allocated from update_ssa_obstack. */ |
212 | bitmap repl_set; | |
b4e209fd | 213 | |
8812aab1 | 214 | /* Information stored for both SSA names and decls. */ |
526ceb68 | 215 | common_info info; |
5f240ec4 | 216 | }; |
6de9cd9a | 217 | |
526ceb68 | 218 | static vec<ssa_name_info *> info_for_ssa_name; |
95dd3097 ZD |
219 | static unsigned current_info_for_ssa_name_age; |
220 | ||
891f2df6 RG |
221 | static bitmap_obstack update_ssa_obstack; |
222 | ||
95dd3097 | 223 | /* The set of blocks affected by update_ssa. */ |
95dd3097 | 224 | static bitmap blocks_to_update; |
6de9cd9a | 225 | |
0bca51f0 DN |
226 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
227 | called several times to do different, but related, tasks. | |
228 | Initially, we need it to rename the whole program into SSA form. | |
229 | At other times, we may need it to only rename into SSA newly | |
230 | exposed symbols. Finally, we can also call it to incrementally fix | |
231 | an already built SSA web. */ | |
232 | enum rewrite_mode { | |
233 | /* Convert the whole function into SSA form. */ | |
234 | REWRITE_ALL, | |
235 | ||
236 | /* Incrementally update the SSA web by replacing existing SSA | |
237 | names with new ones. See update_ssa for details. */ | |
238 | REWRITE_UPDATE | |
239 | }; | |
240 | ||
13714310 RG |
241 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ |
242 | static bitmap symbols_to_rename_set; | |
9771b263 | 243 | static vec<tree> symbols_to_rename; |
13714310 RG |
244 | |
245 | /* Mark SYM for renaming. */ | |
246 | ||
247 | static void | |
248 | mark_for_renaming (tree sym) | |
249 | { | |
250 | if (!symbols_to_rename_set) | |
251 | symbols_to_rename_set = BITMAP_ALLOC (NULL); | |
252 | if (bitmap_set_bit (symbols_to_rename_set, DECL_UID (sym))) | |
9771b263 | 253 | symbols_to_rename.safe_push (sym); |
13714310 RG |
254 | } |
255 | ||
256 | /* Return true if SYM is marked for renaming. */ | |
257 | ||
258 | static bool | |
259 | marked_for_renaming (tree sym) | |
260 | { | |
70b5e7dc | 261 | if (!symbols_to_rename_set || sym == NULL_TREE) |
13714310 RG |
262 | return false; |
263 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
264 | } | |
265 | ||
266 | ||
726a989a RB |
267 | /* Return true if STMT needs to be rewritten. When renaming a subset |
268 | of the variables, not all statements will be processed. This is | |
269 | decided in mark_def_sites. */ | |
270 | ||
271 | static inline bool | |
355fe088 | 272 | rewrite_uses_p (gimple *stmt) |
726a989a RB |
273 | { |
274 | return gimple_visited_p (stmt); | |
275 | } | |
276 | ||
277 | ||
278 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
279 | ||
280 | static inline void | |
355fe088 | 281 | set_rewrite_uses (gimple *stmt, bool rewrite_p) |
726a989a RB |
282 | { |
283 | gimple_set_visited (stmt, rewrite_p); | |
284 | } | |
285 | ||
286 | ||
287 | /* Return true if the DEFs created by statement STMT should be | |
288 | registered when marking new definition sites. This is slightly | |
289 | different than rewrite_uses_p: it's used by update_ssa to | |
290 | distinguish statements that need to have both uses and defs | |
291 | processed from those that only need to have their defs processed. | |
292 | Statements that define new SSA names only need to have their defs | |
293 | registered, but they don't need to have their uses renamed. */ | |
294 | ||
295 | static inline bool | |
355fe088 | 296 | register_defs_p (gimple *stmt) |
726a989a RB |
297 | { |
298 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
299 | } | |
300 | ||
301 | ||
302 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
303 | ||
304 | static inline void | |
355fe088 | 305 | set_register_defs (gimple *stmt, bool register_defs_p) |
726a989a RB |
306 | { |
307 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
308 | } | |
309 | ||
310 | ||
5f240ec4 ZD |
311 | /* Get the information associated with NAME. */ |
312 | ||
526ceb68 | 313 | static inline ssa_name_info * |
5f240ec4 ZD |
314 | get_ssa_name_ann (tree name) |
315 | { | |
95dd3097 | 316 | unsigned ver = SSA_NAME_VERSION (name); |
9771b263 | 317 | unsigned len = info_for_ssa_name.length (); |
95dd3097 ZD |
318 | struct ssa_name_info *info; |
319 | ||
f5843d08 | 320 | /* Re-allocate the vector at most once per update/into-SSA. */ |
95dd3097 | 321 | if (ver >= len) |
9771b263 | 322 | info_for_ssa_name.safe_grow_cleared (num_ssa_names); |
f5843d08 RG |
323 | |
324 | /* But allocate infos lazily. */ | |
9771b263 | 325 | info = info_for_ssa_name[ver]; |
f5843d08 | 326 | if (!info) |
95dd3097 | 327 | { |
f5843d08 RG |
328 | info = XCNEW (struct ssa_name_info); |
329 | info->age = current_info_for_ssa_name_age; | |
330 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
9771b263 | 331 | info_for_ssa_name[ver] = info; |
95dd3097 ZD |
332 | } |
333 | ||
95dd3097 ZD |
334 | if (info->age < current_info_for_ssa_name_age) |
335 | { | |
95dd3097 | 336 | info->age = current_info_for_ssa_name_age; |
8812aab1 RG |
337 | info->repl_set = NULL; |
338 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
339 | info->info.current_def = NULL_TREE; | |
340 | info->info.def_blocks.def_blocks = NULL; | |
341 | info->info.def_blocks.phi_blocks = NULL; | |
342 | info->info.def_blocks.livein_blocks = NULL; | |
95dd3097 | 343 | } |
5f240ec4 | 344 | |
95dd3097 | 345 | return info; |
5f240ec4 ZD |
346 | } |
347 | ||
b4e209fd RG |
348 | /* Return and allocate the auxiliar information for DECL. */ |
349 | ||
526ceb68 | 350 | static inline var_info * |
b4e209fd RG |
351 | get_var_info (tree decl) |
352 | { | |
526ceb68 TS |
353 | var_info vi; |
354 | var_info **slot; | |
b4e209fd | 355 | vi.var = decl; |
c203e8a7 | 356 | slot = var_infos->find_slot_with_hash (&vi, DECL_UID (decl), INSERT); |
b4e209fd RG |
357 | if (*slot == NULL) |
358 | { | |
526ceb68 | 359 | var_info *v = XCNEW (var_info); |
b4e209fd | 360 | v->var = decl; |
bf190e8d | 361 | *slot = v; |
b4e209fd RG |
362 | return v; |
363 | } | |
bf190e8d | 364 | return *slot; |
b4e209fd RG |
365 | } |
366 | ||
38635499 DN |
367 | |
368 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
369 | |
370 | static void | |
371 | clear_ssa_name_info (void) | |
372 | { | |
373 | current_info_for_ssa_name_age++; | |
891f2df6 RG |
374 | |
375 | /* If current_info_for_ssa_name_age wraps we use stale information. | |
376 | Asser that this does not happen. */ | |
377 | gcc_assert (current_info_for_ssa_name_age != 0); | |
95dd3097 | 378 | } |
7256233c | 379 | |
38635499 | 380 | |
8812aab1 | 381 | /* Get access to the auxiliar information stored per SSA name or decl. */ |
5f240ec4 | 382 | |
526ceb68 | 383 | static inline common_info * |
8812aab1 | 384 | get_common_info (tree var) |
5f240ec4 ZD |
385 | { |
386 | if (TREE_CODE (var) == SSA_NAME) | |
8812aab1 | 387 | return &get_ssa_name_ann (var)->info; |
5f240ec4 | 388 | else |
8812aab1 | 389 | return &get_var_info (var)->info; |
5f240ec4 ZD |
390 | } |
391 | ||
7256233c | 392 | |
5f240ec4 ZD |
393 | /* Return the current definition for VAR. */ |
394 | ||
84d65814 | 395 | tree |
5f240ec4 ZD |
396 | get_current_def (tree var) |
397 | { | |
8812aab1 | 398 | return get_common_info (var)->current_def; |
5f240ec4 ZD |
399 | } |
400 | ||
7256233c | 401 | |
5f240ec4 ZD |
402 | /* Sets current definition of VAR to DEF. */ |
403 | ||
84d65814 | 404 | void |
5f240ec4 ZD |
405 | set_current_def (tree var, tree def) |
406 | { | |
8812aab1 | 407 | get_common_info (var)->current_def = def; |
5f240ec4 ZD |
408 | } |
409 | ||
95dd3097 ZD |
410 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
411 | all statements in basic block BB. */ | |
412 | ||
413 | static void | |
414 | initialize_flags_in_bb (basic_block bb) | |
415 | { | |
355fe088 | 416 | gimple *stmt; |
726a989a | 417 | gimple_stmt_iterator gsi; |
95dd3097 | 418 | |
726a989a | 419 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 420 | { |
355fe088 | 421 | gimple *phi = gsi_stmt (gsi); |
726a989a RB |
422 | set_rewrite_uses (phi, false); |
423 | set_register_defs (phi, false); | |
95dd3097 ZD |
424 | } |
425 | ||
726a989a | 426 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 427 | { |
726a989a RB |
428 | stmt = gsi_stmt (gsi); |
429 | ||
95dd3097 ZD |
430 | /* We are going to use the operand cache API, such as |
431 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
432 | cache for each statement should be up-to-date. */ | |
4ad14919 | 433 | gcc_checking_assert (!gimple_modified_p (stmt)); |
726a989a RB |
434 | set_rewrite_uses (stmt, false); |
435 | set_register_defs (stmt, false); | |
95dd3097 ZD |
436 | } |
437 | } | |
438 | ||
439 | /* Mark block BB as interesting for update_ssa. */ | |
440 | ||
441 | static void | |
442 | mark_block_for_update (basic_block bb) | |
443 | { | |
4ad14919 | 444 | gcc_checking_assert (blocks_to_update != NULL); |
f3cf730b | 445 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
95dd3097 | 446 | return; |
95dd3097 ZD |
447 | initialize_flags_in_bb (bb); |
448 | } | |
449 | ||
7256233c DN |
450 | /* Return the set of blocks where variable VAR is defined and the blocks |
451 | where VAR is live on entry (livein). If no entry is found in | |
452 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 453 | |
526ceb68 TS |
454 | static inline def_blocks * |
455 | get_def_blocks_for (common_info *info) | |
6de9cd9a | 456 | { |
526ceb68 | 457 | def_blocks *db_p = &info->def_blocks; |
b4e209fd | 458 | if (!db_p->def_blocks) |
6de9cd9a | 459 | { |
b4e209fd RG |
460 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
461 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
462 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
a32b97a2 BB |
463 | } |
464 | ||
7256233c | 465 | return db_p; |
6de9cd9a DN |
466 | } |
467 | ||
7d5f9cc6 | 468 | |
5f240ec4 | 469 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 470 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
471 | |
472 | static void | |
0bca51f0 | 473 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a | 474 | { |
526ceb68 TS |
475 | def_blocks *db_p; |
476 | common_info *info; | |
34eb8991 | 477 | |
8812aab1 RG |
478 | info = get_common_info (var); |
479 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
480 | |
481 | /* Set the bit corresponding to the block where VAR is defined. */ | |
482 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
483 | if (phi_p) |
484 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 485 | |
7256233c | 486 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
487 | |
488 | If we are in the UNKNOWN state, then this is the first definition | |
489 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 490 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
491 | transition to NEED_PHI_STATE_NO). |
492 | ||
493 | If we are in any other state, then we either have multiple definitions | |
494 | of this variable occurring in different blocks or we saw a use of the | |
495 | variable which was not dominated by the block containing the | |
496 | definition(s). In this case we may need a PHI node, so enter | |
497 | state NEED_PHI_STATE_MAYBE. */ | |
8812aab1 RG |
498 | if (info->need_phi_state == NEED_PHI_STATE_UNKNOWN) |
499 | info->need_phi_state = NEED_PHI_STATE_NO; | |
6de9cd9a | 500 | else |
8812aab1 | 501 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
502 | } |
503 | ||
504 | ||
505 | /* Mark block BB as having VAR live at the entry to BB. */ | |
506 | ||
507 | static void | |
508 | set_livein_block (tree var, basic_block bb) | |
509 | { | |
526ceb68 TS |
510 | common_info *info; |
511 | def_blocks *db_p; | |
6de9cd9a | 512 | |
8812aab1 RG |
513 | info = get_common_info (var); |
514 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
515 | |
516 | /* Set the bit corresponding to the block where VAR is live in. */ | |
517 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
518 | ||
7256233c | 519 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
520 | |
521 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
522 | by the single block containing the definition(s) of this variable. If | |
523 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
524 | NEED_PHI_STATE_MAYBE. */ | |
8812aab1 | 525 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
6de9cd9a DN |
526 | { |
527 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
528 | ||
529 | if (def_block_index == -1 | |
530 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
06e28de2 | 531 | BASIC_BLOCK_FOR_FN (cfun, def_block_index))) |
8812aab1 | 532 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
533 | } |
534 | else | |
8812aab1 | 535 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
536 | } |
537 | ||
538 | ||
0bca51f0 | 539 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
6de9cd9a | 540 | |
0bca51f0 DN |
541 | static inline bool |
542 | is_old_name (tree name) | |
543 | { | |
84d65814 | 544 | unsigned ver = SSA_NAME_VERSION (name); |
c36eadbe | 545 | if (!old_ssa_names) |
5006671f | 546 | return false; |
c36eadbe | 547 | return (ver < SBITMAP_SIZE (old_ssa_names) |
d7c028c0 | 548 | && bitmap_bit_p (old_ssa_names, ver)); |
0bca51f0 DN |
549 | } |
550 | ||
551 | ||
552 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 553 | |
0bca51f0 DN |
554 | static inline bool |
555 | is_new_name (tree name) | |
556 | { | |
84d65814 | 557 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
558 | if (!new_ssa_names) |
559 | return false; | |
5829cc0f | 560 | return (ver < SBITMAP_SIZE (new_ssa_names) |
d7c028c0 | 561 | && bitmap_bit_p (new_ssa_names, ver)); |
6de9cd9a DN |
562 | } |
563 | ||
7256233c | 564 | |
82d6e6fc | 565 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
566 | |
567 | static inline bitmap | |
82d6e6fc | 568 | names_replaced_by (tree new_tree) |
0bca51f0 | 569 | { |
891f2df6 | 570 | return get_ssa_name_ann (new_tree)->repl_set; |
0bca51f0 DN |
571 | } |
572 | ||
573 | ||
82d6e6fc | 574 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
575 | |
576 | static inline void | |
82d6e6fc | 577 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 | 578 | { |
891f2df6 RG |
579 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
580 | if (!*set) | |
581 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
582 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
0bca51f0 DN |
583 | } |
584 | ||
585 | ||
82d6e6fc | 586 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
587 | represents the set of names O_1 ... O_j replaced by N_i. This is |
588 | used by update_ssa and its helpers to introduce new SSA names in an | |
589 | already formed SSA web. */ | |
590 | ||
591 | static void | |
82d6e6fc | 592 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 | 593 | { |
82d6e6fc | 594 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
4ad14919 RG |
595 | gcc_checking_assert (new_tree != old |
596 | && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 597 | |
38635499 DN |
598 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
599 | caller may have created new names since the set was created. */ | |
5829cc0f | 600 | if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1) |
38635499 DN |
601 | { |
602 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
603 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
604 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
605 | } |
606 | ||
0bca51f0 | 607 | /* Update the REPL_TBL table. */ |
82d6e6fc | 608 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 609 | |
0bca51f0 | 610 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 611 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 612 | if (is_new_name (old)) |
82d6e6fc | 613 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 614 | |
82d6e6fc | 615 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 616 | respectively. */ |
d7c028c0 LC |
617 | bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
618 | bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old)); | |
d00ad49b | 619 | } |
6de9cd9a | 620 | |
6de9cd9a | 621 | |
7256233c DN |
622 | /* Call back for walk_dominator_tree used to collect definition sites |
623 | for every variable in the function. For every statement S in block | |
624 | BB: | |
6de9cd9a | 625 | |
f47c96aa | 626 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
ccf5c864 | 627 | KILLS. |
6de9cd9a | 628 | |
7256233c | 629 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 630 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 631 | |
7256233c DN |
632 | This information is used to determine which variables are live |
633 | across block boundaries to reduce the number of PHI nodes | |
634 | we create. */ | |
6de9cd9a | 635 | |
7256233c | 636 | static void |
355fe088 | 637 | mark_def_sites (basic_block bb, gimple *stmt, bitmap kills) |
7256233c | 638 | { |
726a989a | 639 | tree def; |
7256233c | 640 | use_operand_p use_p; |
7256233c DN |
641 | ssa_op_iter iter; |
642 | ||
726a989a RB |
643 | /* Since this is the first time that we rewrite the program into SSA |
644 | form, force an operand scan on every statement. */ | |
726a989a | 645 | update_stmt (stmt); |
7256233c | 646 | |
4ad14919 | 647 | gcc_checking_assert (blocks_to_update == NULL); |
726a989a RB |
648 | set_register_defs (stmt, false); |
649 | set_rewrite_uses (stmt, false); | |
7256233c | 650 | |
b5b8b0ac | 651 | if (is_gimple_debug (stmt)) |
ddb555ed JJ |
652 | { |
653 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
654 | { | |
655 | tree sym = USE_FROM_PTR (use_p); | |
4ad14919 | 656 | gcc_checking_assert (DECL_P (sym)); |
ddb555ed JJ |
657 | set_rewrite_uses (stmt, true); |
658 | } | |
659 | if (rewrite_uses_p (stmt)) | |
d7c028c0 | 660 | bitmap_set_bit (interesting_blocks, bb->index); |
ddb555ed JJ |
661 | return; |
662 | } | |
b5b8b0ac | 663 | |
7256233c DN |
664 | /* If a variable is used before being set, then the variable is live |
665 | across a block boundary, so mark it live-on-entry to BB. */ | |
39c58b3a | 666 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
7256233c | 667 | { |
0bca51f0 | 668 | tree sym = USE_FROM_PTR (use_p); |
4ad14919 | 669 | gcc_checking_assert (DECL_P (sym)); |
a3648cfc | 670 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 671 | set_livein_block (sym, bb); |
726a989a | 672 | set_rewrite_uses (stmt, true); |
7256233c | 673 | } |
b8698a0f | 674 | |
38635499 DN |
675 | /* Now process the defs. Mark BB as the definition block and add |
676 | each def to the set of killed symbols. */ | |
39c58b3a | 677 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
7256233c | 678 | { |
4ad14919 | 679 | gcc_checking_assert (DECL_P (def)); |
0bca51f0 | 680 | set_def_block (def, bb, false); |
a3648cfc | 681 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 682 | set_register_defs (stmt, true); |
7256233c | 683 | } |
0bca51f0 DN |
684 | |
685 | /* If we found the statement interesting then also mark the block BB | |
686 | as interesting. */ | |
726a989a | 687 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
d7c028c0 | 688 | bitmap_set_bit (interesting_blocks, bb->index); |
7256233c DN |
689 | } |
690 | ||
f074ff6c ZD |
691 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
692 | in the dfs numbering of the dominance tree. */ | |
693 | ||
694 | struct dom_dfsnum | |
695 | { | |
696 | /* Basic block whose index this entry corresponds to. */ | |
697 | unsigned bb_index; | |
698 | ||
699 | /* The dfs number of this node. */ | |
700 | unsigned dfs_num; | |
701 | }; | |
702 | ||
703 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
704 | for qsort. */ | |
705 | ||
706 | static int | |
707 | cmp_dfsnum (const void *a, const void *b) | |
708 | { | |
3d9a9f94 KG |
709 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
710 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
711 | |
712 | return (int) da->dfs_num - (int) db->dfs_num; | |
713 | } | |
714 | ||
715 | /* Among the intervals starting at the N points specified in DEFS, find | |
716 | the one that contains S, and return its bb_index. */ | |
717 | ||
718 | static unsigned | |
719 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
720 | { | |
721 | unsigned f = 0, t = n, m; | |
722 | ||
723 | while (t > f + 1) | |
724 | { | |
725 | m = (f + t) / 2; | |
726 | if (defs[m].dfs_num <= s) | |
727 | f = m; | |
728 | else | |
729 | t = m; | |
730 | } | |
731 | ||
732 | return defs[f].bb_index; | |
733 | } | |
734 | ||
735 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
736 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
737 | ||
738 | static void | |
739 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
740 | { | |
f074ff6c ZD |
741 | bitmap_iterator bi; |
742 | unsigned i, b, p, u, top; | |
743 | bitmap live_phis; | |
744 | basic_block def_bb, use_bb; | |
745 | edge e; | |
746 | edge_iterator ei; | |
747 | bitmap to_remove; | |
748 | struct dom_dfsnum *defs; | |
749 | unsigned n_defs, adef; | |
750 | ||
751 | if (bitmap_empty_p (uses)) | |
752 | { | |
753 | bitmap_clear (phis); | |
754 | return; | |
755 | } | |
756 | ||
757 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
758 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
759 | to_remove = BITMAP_ALLOC (NULL); | |
760 | bitmap_and_compl (to_remove, kills, uses); | |
761 | bitmap_and_compl_into (phis, to_remove); | |
762 | if (bitmap_empty_p (phis)) | |
763 | { | |
764 | BITMAP_FREE (to_remove); | |
765 | return; | |
766 | } | |
767 | ||
768 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
769 | liveness information, as that may be linear in the size of CFG, and if | |
770 | there are lot of different variables to rewrite, this may lead to quadratic | |
771 | behavior. | |
772 | ||
773 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
774 | then for each of them find the nearest def that dominates them. If this | |
775 | def is a phi node, we mark it live, and if it was not live before, we | |
776 | add the predecessors of its basic block to the worklist. | |
b8698a0f | 777 | |
f074ff6c ZD |
778 | To quickly locate the nearest def that dominates use, we use dfs numbering |
779 | of the dominance tree (that is already available in order to speed up | |
780 | queries). For each def, we have the interval given by the dfs number on | |
781 | entry to and on exit from the corresponding subtree in the dominance tree. | |
782 | The nearest dominator for a given use is the smallest of these intervals | |
783 | that contains entry and exit dfs numbers for the basic block with the use. | |
784 | If we store the bounds for all the uses to an array and sort it, we can | |
785 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
786 | bitmap_ior (to_remove, kills, phis); | |
787 | n_defs = bitmap_count_bits (to_remove); | |
788 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
789 | defs[0].bb_index = 1; | |
790 | defs[0].dfs_num = 0; | |
791 | adef = 1; | |
792 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
793 | { | |
06e28de2 | 794 | def_bb = BASIC_BLOCK_FOR_FN (cfun, i); |
f074ff6c ZD |
795 | defs[adef].bb_index = i; |
796 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
797 | defs[adef + 1].bb_index = i; | |
798 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
799 | adef += 2; | |
800 | } | |
801 | BITMAP_FREE (to_remove); | |
802 | gcc_assert (adef == 2 * n_defs + 1); | |
803 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
804 | gcc_assert (defs[0].bb_index == 1); | |
805 | ||
806 | /* Now each DEFS entry contains the number of the basic block to that the | |
807 | dfs number corresponds. Change them to the number of basic block that | |
808 | corresponds to the interval following the dfs number. Also, for the | |
809 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
810 | to the start of the following interval, not to the end of the current | |
811 | one). We use WORKLIST as a stack. */ | |
ef062b13 | 812 | auto_vec<int> worklist (n_defs + 1); |
9771b263 | 813 | worklist.quick_push (1); |
f074ff6c ZD |
814 | top = 1; |
815 | n_defs = 1; | |
816 | for (i = 1; i < adef; i++) | |
817 | { | |
818 | b = defs[i].bb_index; | |
819 | if (b == top) | |
820 | { | |
821 | /* This is a closing element. Interval corresponding to the top | |
822 | of the stack after removing it follows. */ | |
9771b263 DN |
823 | worklist.pop (); |
824 | top = worklist[worklist.length () - 1]; | |
f074ff6c ZD |
825 | defs[n_defs].bb_index = top; |
826 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
827 | } | |
828 | else | |
829 | { | |
830 | /* Opening element. Nothing to do, just push it to the stack and move | |
831 | it to the correct position. */ | |
832 | defs[n_defs].bb_index = defs[i].bb_index; | |
833 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
9771b263 | 834 | worklist.quick_push (b); |
f074ff6c ZD |
835 | top = b; |
836 | } | |
837 | ||
838 | /* If this interval starts at the same point as the previous one, cancel | |
839 | the previous one. */ | |
840 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
841 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
842 | else | |
843 | n_defs++; | |
844 | } | |
9771b263 DN |
845 | worklist.pop (); |
846 | gcc_assert (worklist.is_empty ()); | |
f074ff6c ZD |
847 | |
848 | /* Now process the uses. */ | |
849 | live_phis = BITMAP_ALLOC (NULL); | |
850 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
851 | { | |
9771b263 | 852 | worklist.safe_push (i); |
f074ff6c ZD |
853 | } |
854 | ||
9771b263 | 855 | while (!worklist.is_empty ()) |
f074ff6c | 856 | { |
9771b263 | 857 | b = worklist.pop (); |
f074ff6c ZD |
858 | if (b == ENTRY_BLOCK) |
859 | continue; | |
860 | ||
861 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
862 | find the def that dominates the immediate dominator of USE_BB | |
863 | (the kill in USE_BB does not dominate the use). */ | |
864 | if (bitmap_bit_p (phis, b)) | |
865 | p = b; | |
866 | else | |
867 | { | |
06e28de2 DM |
868 | use_bb = get_immediate_dominator (CDI_DOMINATORS, |
869 | BASIC_BLOCK_FOR_FN (cfun, b)); | |
f074ff6c ZD |
870 | p = find_dfsnum_interval (defs, n_defs, |
871 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
872 | if (!bitmap_bit_p (phis, p)) | |
873 | continue; | |
874 | } | |
875 | ||
876 | /* If the phi node is already live, there is nothing to do. */ | |
fcaa4ca4 | 877 | if (!bitmap_set_bit (live_phis, p)) |
f074ff6c ZD |
878 | continue; |
879 | ||
fcaa4ca4 | 880 | /* Add the new uses to the worklist. */ |
06e28de2 | 881 | def_bb = BASIC_BLOCK_FOR_FN (cfun, p); |
f074ff6c ZD |
882 | FOR_EACH_EDGE (e, ei, def_bb->preds) |
883 | { | |
884 | u = e->src->index; | |
885 | if (bitmap_bit_p (uses, u)) | |
886 | continue; | |
887 | ||
1e5787ef ZD |
888 | /* In case there is a kill directly in the use block, do not record |
889 | the use (this is also necessary for correctness, as we assume that | |
890 | uses dominated by a def directly in their block have been filtered | |
891 | out before). */ | |
892 | if (bitmap_bit_p (kills, u)) | |
893 | continue; | |
894 | ||
f074ff6c | 895 | bitmap_set_bit (uses, u); |
9771b263 | 896 | worklist.safe_push (u); |
f074ff6c ZD |
897 | } |
898 | } | |
899 | ||
f074ff6c ZD |
900 | bitmap_copy (phis, live_phis); |
901 | BITMAP_FREE (live_phis); | |
902 | free (defs); | |
903 | } | |
7256233c | 904 | |
7256233c DN |
905 | /* Return the set of blocks where variable VAR is defined and the blocks |
906 | where VAR is live on entry (livein). Return NULL, if no entry is | |
907 | found in DEF_BLOCKS. */ | |
908 | ||
526ceb68 | 909 | static inline def_blocks * |
7256233c DN |
910 | find_def_blocks_for (tree var) |
911 | { | |
526ceb68 | 912 | def_blocks *p = &get_common_info (var)->def_blocks; |
b4e209fd RG |
913 | if (!p->def_blocks) |
914 | return NULL; | |
915 | return p; | |
7256233c DN |
916 | } |
917 | ||
918 | ||
2ce79879 ZD |
919 | /* Marks phi node PHI in basic block BB for rewrite. */ |
920 | ||
921 | static void | |
538dd0b7 | 922 | mark_phi_for_rewrite (basic_block bb, gphi *phi) |
2ce79879 | 923 | { |
538dd0b7 | 924 | vec<gphi *> phis; |
580b2c2e | 925 | unsigned n, idx = bb->index; |
2ce79879 | 926 | |
726a989a | 927 | if (rewrite_uses_p (phi)) |
2ce79879 | 928 | return; |
38635499 | 929 | |
726a989a | 930 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
931 | |
932 | if (!blocks_with_phis_to_rewrite) | |
933 | return; | |
934 | ||
935 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
580b2c2e | 936 | |
8b1c6fd7 | 937 | n = (unsigned) last_basic_block_for_fn (cfun) + 1; |
9771b263 DN |
938 | if (phis_to_rewrite.length () < n) |
939 | phis_to_rewrite.safe_grow_cleared (n); | |
2ce79879 | 940 | |
9771b263 DN |
941 | phis = phis_to_rewrite[idx]; |
942 | phis.reserve (10); | |
2ce79879 | 943 | |
9771b263 DN |
944 | phis.safe_push (phi); |
945 | phis_to_rewrite[idx] = phis; | |
2ce79879 ZD |
946 | } |
947 | ||
7256233c | 948 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 949 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
950 | function assumes that the caller is incrementally updating the |
951 | existing SSA form, in which case VAR may be an SSA name instead of | |
952 | a symbol. | |
0bca51f0 DN |
953 | |
954 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
955 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
956 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
957 | |
958 | static void | |
0bca51f0 | 959 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
960 | { |
961 | unsigned bb_index; | |
962 | edge e; | |
538dd0b7 | 963 | gphi *phi; |
7256233c DN |
964 | basic_block bb; |
965 | bitmap_iterator bi; | |
526ceb68 | 966 | def_blocks *def_map = find_def_blocks_for (var); |
7256233c DN |
967 | |
968 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
969 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
970 | ||
f074ff6c ZD |
971 | /* Remove obviously useless phi nodes. */ |
972 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
973 | def_map->livein_blocks); | |
7256233c DN |
974 | |
975 | /* And insert the PHI nodes. */ | |
f074ff6c | 976 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c | 977 | { |
06e28de2 | 978 | bb = BASIC_BLOCK_FOR_FN (cfun, bb_index); |
95dd3097 ZD |
979 | if (update_p) |
980 | mark_block_for_update (bb); | |
7256233c | 981 | |
fa5556de RB |
982 | if (dump_file && (dump_flags & TDF_DETAILS)) |
983 | { | |
984 | fprintf (dump_file, "creating PHI node in block #%d for ", bb_index); | |
985 | print_generic_expr (dump_file, var, TDF_SLIM); | |
986 | fprintf (dump_file, "\n"); | |
987 | } | |
726a989a | 988 | phi = NULL; |
38635499 DN |
989 | |
990 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 991 | { |
84d65814 DN |
992 | /* If we are rewriting SSA names, create the LHS of the PHI |
993 | node by duplicating VAR. This is useful in the case of | |
994 | pointers, to also duplicate pointer attributes (alias | |
995 | information, in particular). */ | |
7256233c | 996 | edge_iterator ei; |
84d65814 | 997 | tree new_lhs; |
0bca51f0 | 998 | |
4ad14919 | 999 | gcc_checking_assert (update_p); |
dcc748dd RG |
1000 | new_lhs = duplicate_ssa_name (var, NULL); |
1001 | phi = create_phi_node (new_lhs, bb); | |
84d65814 | 1002 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1003 | |
1004 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1005 | every argument so that rewrite_update_phi_arguments knows | |
1006 | which name is this PHI node replacing. If VAR is a | |
1007 | symbol marked for renaming, this is not necessary, the | |
1008 | renamer will use the symbol on the LHS to get its | |
1009 | reaching definition. */ | |
7256233c | 1010 | FOR_EACH_EDGE (e, ei, bb->preds) |
9e227d60 | 1011 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
7256233c | 1012 | } |
84d65814 DN |
1013 | else |
1014 | { | |
b5b8b0ac | 1015 | tree tracked_var; |
3a56edc7 | 1016 | |
4ad14919 | 1017 | gcc_checking_assert (DECL_P (var)); |
e24c4814 | 1018 | phi = create_phi_node (var, bb); |
3a56edc7 AO |
1019 | |
1020 | tracked_var = target_for_debug_bind (var); | |
1021 | if (tracked_var) | |
b5b8b0ac | 1022 | { |
355fe088 TS |
1023 | gimple *note = gimple_build_debug_bind (tracked_var, |
1024 | PHI_RESULT (phi), | |
b5b8b0ac AO |
1025 | phi); |
1026 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1027 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1028 | } | |
84d65814 | 1029 | } |
0bca51f0 DN |
1030 | |
1031 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1032 | set_register_defs (phi, true); |
2ce79879 | 1033 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1034 | } |
1035 | } | |
1036 | ||
b4e209fd | 1037 | /* Sort var_infos after DECL_UID of their var. */ |
d9ed2fbd RG |
1038 | |
1039 | static int | |
b4e209fd | 1040 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
d9ed2fbd | 1041 | { |
526ceb68 TS |
1042 | const var_info *defa = *(var_info * const *)a; |
1043 | const var_info *defb = *(var_info * const *)b; | |
d9ed2fbd RG |
1044 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1045 | return -1; | |
1046 | else | |
1047 | return 1; | |
1048 | } | |
7256233c | 1049 | |
7256233c DN |
1050 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1051 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1052 | the flowgraph. */ |
7256233c DN |
1053 | |
1054 | static void | |
0fc555fb | 1055 | insert_phi_nodes (bitmap_head *dfs) |
7256233c | 1056 | { |
c203e8a7 | 1057 | hash_table<var_info_hasher>::iterator hi; |
d9ed2fbd | 1058 | unsigned i; |
526ceb68 | 1059 | var_info *info; |
7256233c DN |
1060 | |
1061 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
b8698a0f | 1062 | |
526ceb68 | 1063 | auto_vec<var_info *> vars (var_infos->elements ()); |
c203e8a7 | 1064 | FOR_EACH_HASH_TABLE_ELEMENT (*var_infos, info, var_info_p, hi) |
8812aab1 | 1065 | if (info->info.need_phi_state != NEED_PHI_STATE_NO) |
9771b263 | 1066 | vars.quick_push (info); |
d9ed2fbd | 1067 | |
e68c7b43 RG |
1068 | /* Do two stages to avoid code generation differences for UID |
1069 | differences but no UID ordering differences. */ | |
9771b263 | 1070 | vars.qsort (insert_phi_nodes_compare_var_infos); |
e68c7b43 | 1071 | |
9771b263 | 1072 | FOR_EACH_VEC_ELT (vars, i, info) |
5f240ec4 | 1073 | { |
8812aab1 | 1074 | bitmap idf = compute_idf (info->info.def_blocks.def_blocks, dfs); |
b4e209fd | 1075 | insert_phi_nodes_for (info->var, idf, false); |
e68c7b43 RG |
1076 | BITMAP_FREE (idf); |
1077 | } | |
1078 | ||
6de9cd9a DN |
1079 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1080 | } | |
1081 | ||
1082 | ||
38635499 DN |
1083 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1084 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1085 | |
cfaab3a9 | 1086 | static void |
38635499 | 1087 | register_new_def (tree def, tree sym) |
7256233c | 1088 | { |
526ceb68 | 1089 | common_info *info = get_common_info (sym); |
7256233c | 1090 | tree currdef; |
b8698a0f | 1091 | |
7256233c DN |
1092 | /* If this variable is set in a single basic block and all uses are |
1093 | dominated by the set(s) in that single basic block, then there is | |
1094 | no reason to record anything for this variable in the block local | |
1095 | definition stacks. Doing so just wastes time and memory. | |
1096 | ||
1097 | This is the same test to prune the set of variables which may | |
1098 | need PHI nodes. So we just use that information since it's already | |
1099 | computed and available for us to use. */ | |
8812aab1 | 1100 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
7256233c | 1101 | { |
8812aab1 | 1102 | info->current_def = def; |
7256233c DN |
1103 | return; |
1104 | } | |
1105 | ||
8812aab1 | 1106 | currdef = info->current_def; |
7256233c | 1107 | |
38635499 DN |
1108 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1109 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1110 | in the stack so that we know which symbol is being defined by | |
1111 | this SSA name when we unwind the stack. */ | |
1112 | if (currdef && !is_gimple_reg (sym)) | |
9771b263 | 1113 | block_defs_stack.safe_push (sym); |
7256233c | 1114 | |
38635499 DN |
1115 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1116 | stack is later used by the dominator tree callbacks to restore | |
1117 | the reaching definitions for all the variables defined in the | |
1118 | block after a recursive visit to all its immediately dominated | |
1119 | blocks. If there is no current reaching definition, then just | |
1120 | record the underlying _DECL node. */ | |
9771b263 | 1121 | block_defs_stack.safe_push (currdef ? currdef : sym); |
38635499 DN |
1122 | |
1123 | /* Set the current reaching definition for SYM to be DEF. */ | |
8812aab1 | 1124 | info->current_def = def; |
7256233c DN |
1125 | } |
1126 | ||
1127 | ||
6de9cd9a DN |
1128 | /* Perform a depth-first traversal of the dominator tree looking for |
1129 | variables to rename. BB is the block where to start searching. | |
1130 | Renaming is a five step process: | |
1131 | ||
1132 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1133 | registered as the current definition for the corresponding variable. | |
1134 | ||
1135 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1136 | rewritten with their corresponding reaching definition. DEF and | |
1137 | VDEF targets are registered as new definitions. | |
b8698a0f | 1138 | |
6de9cd9a DN |
1139 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1140 | argument corresponding to BB is replaced with its current reaching | |
1141 | definition. | |
1142 | ||
1143 | 4- Recursively rewrite every dominator child block of BB. | |
1144 | ||
1145 | 5- Restore (in reverse order) the current reaching definition for every | |
1146 | new definition introduced in this block. This is done so that when | |
1147 | we return from the recursive call, all the current reaching | |
1148 | definitions are restored to the names that were valid in the | |
1149 | dominator parent of BB. */ | |
1150 | ||
7256233c | 1151 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1152 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1153 | |
7256233c DN |
1154 | static tree |
1155 | get_reaching_def (tree var) | |
1156 | { | |
526ceb68 | 1157 | common_info *info = get_common_info (var); |
38635499 | 1158 | tree currdef; |
b8698a0f | 1159 | |
7256233c | 1160 | /* Lookup the current reaching definition for VAR. */ |
8812aab1 | 1161 | currdef = info->current_def; |
5f240ec4 | 1162 | |
7256233c DN |
1163 | /* If there is no reaching definition for VAR, create and register a |
1164 | default definition for it (if needed). */ | |
38635499 | 1165 | if (currdef == NULL_TREE) |
7256233c | 1166 | { |
38635499 | 1167 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
32244553 | 1168 | currdef = get_or_create_ssa_default_def (cfun, sym); |
7256233c DN |
1169 | } |
1170 | ||
1171 | /* Return the current reaching definition for VAR, or the default | |
1172 | definition, if we had to create one. */ | |
38635499 | 1173 | return currdef; |
7256233c DN |
1174 | } |
1175 | ||
1176 | ||
ddb555ed JJ |
1177 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1178 | ||
1179 | static void | |
355fe088 | 1180 | rewrite_debug_stmt_uses (gimple *stmt) |
ddb555ed JJ |
1181 | { |
1182 | use_operand_p use_p; | |
1183 | ssa_op_iter iter; | |
1184 | bool update = false; | |
1185 | ||
1186 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1187 | { | |
5f564b8f | 1188 | tree var = USE_FROM_PTR (use_p), def; |
526ceb68 | 1189 | common_info *info = get_common_info (var); |
4ad14919 | 1190 | gcc_checking_assert (DECL_P (var)); |
8812aab1 | 1191 | def = info->current_def; |
5f564b8f | 1192 | if (!def) |
ddb555ed | 1193 | { |
fefa31b5 DM |
1194 | if (TREE_CODE (var) == PARM_DECL |
1195 | && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun))) | |
ddb555ed JJ |
1196 | { |
1197 | gimple_stmt_iterator gsi | |
fefa31b5 DM |
1198 | = |
1199 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1200 | int lim; |
1201 | /* Search a few source bind stmts at the start of first bb to | |
1202 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1203 | for (lim = 32; | |
1204 | !gsi_end_p (gsi) && lim > 0; | |
1205 | gsi_next (&gsi), lim--) | |
1206 | { | |
355fe088 | 1207 | gimple *gstmt = gsi_stmt (gsi); |
ddb555ed JJ |
1208 | if (!gimple_debug_source_bind_p (gstmt)) |
1209 | break; | |
1210 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1211 | { | |
1212 | def = gimple_debug_source_bind_get_var (gstmt); | |
1213 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1214 | break; | |
1215 | else | |
1216 | def = NULL_TREE; | |
1217 | } | |
1218 | } | |
1219 | /* If not, add a new source bind stmt. */ | |
1220 | if (def == NULL_TREE) | |
1221 | { | |
355fe088 | 1222 | gimple *def_temp; |
ddb555ed JJ |
1223 | def = make_node (DEBUG_EXPR_DECL); |
1224 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1225 | DECL_ARTIFICIAL (def) = 1; | |
1226 | TREE_TYPE (def) = TREE_TYPE (var); | |
1227 | DECL_MODE (def) = DECL_MODE (var); | |
fefa31b5 DM |
1228 | gsi = |
1229 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1230 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); |
1231 | } | |
1232 | update = true; | |
1233 | } | |
1234 | } | |
1235 | else | |
15923c25 | 1236 | { |
8812aab1 | 1237 | /* Check if info->current_def can be trusted. */ |
5f564b8f MM |
1238 | basic_block bb = gimple_bb (stmt); |
1239 | basic_block def_bb | |
1240 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1241 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1242 | ||
1243 | /* If definition is in current bb, it is fine. */ | |
1244 | if (bb == def_bb) | |
1245 | ; | |
1246 | /* If definition bb doesn't dominate the current bb, | |
1247 | it can't be used. */ | |
1248 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1249 | def = NULL; | |
1250 | /* If there is just one definition and dominates the current | |
1251 | bb, it is fine. */ | |
8812aab1 | 1252 | else if (info->need_phi_state == NEED_PHI_STATE_NO) |
5f564b8f MM |
1253 | ; |
1254 | else | |
15923c25 | 1255 | { |
526ceb68 | 1256 | def_blocks *db_p = get_def_blocks_for (info); |
15923c25 | 1257 | |
5f564b8f MM |
1258 | /* If there are some non-debug uses in the current bb, |
1259 | it is fine. */ | |
1260 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
15923c25 | 1261 | ; |
5f564b8f | 1262 | /* Otherwise give up for now. */ |
15923c25 | 1263 | else |
5f564b8f | 1264 | def = NULL; |
15923c25 JJ |
1265 | } |
1266 | } | |
ddb555ed JJ |
1267 | if (def == NULL) |
1268 | { | |
1269 | gimple_debug_bind_reset_value (stmt); | |
1270 | update_stmt (stmt); | |
1271 | return; | |
1272 | } | |
1273 | SET_USE (use_p, def); | |
1274 | } | |
1275 | if (update) | |
1276 | update_stmt (stmt); | |
1277 | } | |
1278 | ||
7256233c DN |
1279 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1280 | the block with its immediate reaching definitions. Update the current | |
1281 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1282 | |
1283 | static void | |
5f33a4fc | 1284 | rewrite_stmt (gimple_stmt_iterator *si) |
5f240ec4 | 1285 | { |
7256233c DN |
1286 | use_operand_p use_p; |
1287 | def_operand_p def_p; | |
1288 | ssa_op_iter iter; | |
355fe088 | 1289 | gimple *stmt = gsi_stmt (*si); |
7256233c | 1290 | |
7256233c DN |
1291 | /* If mark_def_sites decided that we don't need to rewrite this |
1292 | statement, ignore it. */ | |
95dd3097 | 1293 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1294 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1295 | return; |
5f240ec4 ZD |
1296 | |
1297 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1298 | { |
1299 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1300 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1301 | fprintf (dump_file, "\n"); |
1302 | } | |
5f240ec4 | 1303 | |
38635499 | 1304 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1305 | if (rewrite_uses_p (stmt)) |
ddb555ed JJ |
1306 | { |
1307 | if (is_gimple_debug (stmt)) | |
1308 | rewrite_debug_stmt_uses (stmt); | |
1309 | else | |
39c58b3a | 1310 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
ddb555ed JJ |
1311 | { |
1312 | tree var = USE_FROM_PTR (use_p); | |
4ad14919 | 1313 | gcc_checking_assert (DECL_P (var)); |
ddb555ed JJ |
1314 | SET_USE (use_p, get_reaching_def (var)); |
1315 | } | |
1316 | } | |
5f240ec4 | 1317 | |
38635499 | 1318 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1319 | if (register_defs_p (stmt)) |
39c58b3a | 1320 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
1321 | { |
1322 | tree var = DEF_FROM_PTR (def_p); | |
5f33a4fc | 1323 | tree name; |
b5b8b0ac | 1324 | tree tracked_var; |
5f33a4fc | 1325 | |
4ad14919 | 1326 | gcc_checking_assert (DECL_P (var)); |
5f33a4fc RG |
1327 | |
1328 | if (gimple_clobber_p (stmt) | |
1329 | && is_gimple_reg (var)) | |
1330 | { | |
1331 | /* If we rewrite a DECL into SSA form then drop its | |
1332 | clobber stmts and replace uses with a new default def. */ | |
4ad14919 RG |
1333 | gcc_checking_assert (TREE_CODE (var) == VAR_DECL |
1334 | && !gimple_vdef (stmt)); | |
5f33a4fc RG |
1335 | gsi_replace (si, gimple_build_nop (), true); |
1336 | register_new_def (get_or_create_ssa_default_def (cfun, var), var); | |
1337 | break; | |
1338 | } | |
1339 | ||
1340 | name = make_ssa_name (var, stmt); | |
b5b8b0ac | 1341 | SET_DEF (def_p, name); |
38635499 | 1342 | register_new_def (DEF_FROM_PTR (def_p), var); |
b5b8b0ac AO |
1343 | |
1344 | tracked_var = target_for_debug_bind (var); | |
1345 | if (tracked_var) | |
1346 | { | |
355fe088 | 1347 | gimple *note = gimple_build_debug_bind (tracked_var, name, stmt); |
5f33a4fc | 1348 | gsi_insert_after (si, note, GSI_SAME_STMT); |
b5b8b0ac | 1349 | } |
0bca51f0 | 1350 | } |
5f240ec4 | 1351 | } |
6de9cd9a | 1352 | |
7256233c | 1353 | |
6de9cd9a DN |
1354 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1355 | PHI nodes. For every PHI node found, add a new argument containing the | |
1356 | current reaching definition for the variable and the edge through which | |
471854f8 | 1357 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1358 | |
1359 | static void | |
ccf5c864 | 1360 | rewrite_add_phi_arguments (basic_block bb) |
6de9cd9a DN |
1361 | { |
1362 | edge e; | |
628f6a4e | 1363 | edge_iterator ei; |
6de9cd9a | 1364 | |
628f6a4e | 1365 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1366 | { |
538dd0b7 DM |
1367 | gphi *phi; |
1368 | gphi_iterator gsi; | |
6de9cd9a | 1369 | |
726a989a RB |
1370 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1371 | gsi_next (&gsi)) | |
6de9cd9a | 1372 | { |
ffc5b2bb RB |
1373 | tree currdef, res; |
1374 | location_t loc; | |
f5045c96 | 1375 | |
538dd0b7 | 1376 | phi = gsi.phi (); |
ffc5b2bb RB |
1377 | res = gimple_phi_result (phi); |
1378 | currdef = get_reaching_def (SSA_NAME_VAR (res)); | |
1379 | /* Virtual operand PHI args do not need a location. */ | |
1380 | if (virtual_operand_p (res)) | |
1381 | loc = UNKNOWN_LOCATION; | |
1382 | else | |
1383 | loc = gimple_location (SSA_NAME_DEF_STMT (currdef)); | |
1384 | add_phi_arg (phi, currdef, e, loc); | |
6de9cd9a DN |
1385 | } |
1386 | } | |
1387 | } | |
1388 | ||
4d9192b5 TS |
1389 | class rewrite_dom_walker : public dom_walker |
1390 | { | |
1391 | public: | |
1392 | rewrite_dom_walker (cdi_direction direction) : dom_walker (direction) {} | |
1393 | ||
3daacdcd | 1394 | virtual edge before_dom_children (basic_block); |
4d9192b5 TS |
1395 | virtual void after_dom_children (basic_block); |
1396 | }; | |
1397 | ||
ccf5c864 PB |
1398 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1399 | of reaching definitions for new SSA names produced in this block | |
1400 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1401 | block. */ | |
1402 | ||
3daacdcd | 1403 | edge |
4d9192b5 | 1404 | rewrite_dom_walker::before_dom_children (basic_block bb) |
ccf5c864 | 1405 | { |
ccf5c864 PB |
1406 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1407 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1408 | ||
1409 | /* Mark the unwind point for this block. */ | |
9771b263 | 1410 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
1411 | |
1412 | /* Step 1. Register new definitions for every PHI node in the block. | |
1413 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1414 | node introduces a new version for the associated variable. */ | |
538dd0b7 DM |
1415 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1416 | gsi_next (&gsi)) | |
ccf5c864 | 1417 | { |
39c58b3a | 1418 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
ccf5c864 PB |
1419 | register_new_def (result, SSA_NAME_VAR (result)); |
1420 | } | |
1421 | ||
1422 | /* Step 2. Rewrite every variable used in each statement in the block | |
1423 | with its immediate reaching definitions. Update the current definition | |
1424 | of a variable when a new real or virtual definition is found. */ | |
d7c028c0 | 1425 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
538dd0b7 DM |
1426 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1427 | gsi_next (&gsi)) | |
5f33a4fc | 1428 | rewrite_stmt (&gsi); |
ccf5c864 PB |
1429 | |
1430 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1431 | For every PHI node found, add a new argument containing the current | |
1432 | reaching definition for the variable and the edge through which that | |
1433 | definition is reaching the PHI node. */ | |
1434 | rewrite_add_phi_arguments (bb); | |
3daacdcd JL |
1435 | |
1436 | return NULL; | |
ccf5c864 PB |
1437 | } |
1438 | ||
1439 | ||
7256233c | 1440 | |
38635499 DN |
1441 | /* Called after visiting all the statements in basic block BB and all |
1442 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a | 1443 | |
4d9192b5 TS |
1444 | void |
1445 | rewrite_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
6de9cd9a | 1446 | { |
9fae925b | 1447 | /* Restore CURRDEFS to its original state. */ |
9771b263 | 1448 | while (block_defs_stack.length () > 0) |
6de9cd9a | 1449 | { |
9771b263 | 1450 | tree tmp = block_defs_stack.pop (); |
6de9cd9a DN |
1451 | tree saved_def, var; |
1452 | ||
9fae925b JL |
1453 | if (tmp == NULL_TREE) |
1454 | break; | |
1455 | ||
6de9cd9a DN |
1456 | if (TREE_CODE (tmp) == SSA_NAME) |
1457 | { | |
38635499 DN |
1458 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1459 | current definition of its underlying variable. Note that | |
1460 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1461 | being defined is stored in the next slot in the stack. | |
1462 | This mechanism is needed because an SSA name for a | |
1463 | non-register symbol may be the definition for more than | |
1464 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1465 | saved_def = tmp; |
1466 | var = SSA_NAME_VAR (saved_def); | |
38635499 | 1467 | if (!is_gimple_reg (var)) |
9771b263 | 1468 | var = block_defs_stack.pop (); |
6de9cd9a DN |
1469 | } |
1470 | else | |
1471 | { | |
38635499 DN |
1472 | /* If we recorded anything else, it must have been a _DECL |
1473 | node and its current reaching definition must have been | |
1474 | NULL. */ | |
6de9cd9a DN |
1475 | saved_def = NULL; |
1476 | var = tmp; | |
1477 | } | |
b8698a0f | 1478 | |
8812aab1 | 1479 | get_common_info (var)->current_def = saved_def; |
6de9cd9a DN |
1480 | } |
1481 | } | |
1482 | ||
1483 | ||
38635499 DN |
1484 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1485 | ||
24e47c76 | 1486 | DEBUG_FUNCTION void |
38635499 DN |
1487 | debug_decl_set (bitmap set) |
1488 | { | |
1489 | dump_decl_set (stderr, set); | |
5006671f | 1490 | fprintf (stderr, "\n"); |
38635499 DN |
1491 | } |
1492 | ||
1493 | ||
1494 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1495 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1496 | dumped. New levels are created when the dominator tree traversal | |
1497 | used for renaming enters a new sub-tree. */ | |
1498 | ||
1499 | void | |
1500 | dump_defs_stack (FILE *file, int n) | |
1501 | { | |
1502 | int i, j; | |
1503 | ||
1504 | fprintf (file, "\n\nRenaming stack"); | |
1505 | if (n > 0) | |
1506 | fprintf (file, " (up to %d levels)", n); | |
1507 | fprintf (file, "\n\n"); | |
1508 | ||
1509 | i = 1; | |
1510 | fprintf (file, "Level %d (current level)\n", i); | |
9771b263 | 1511 | for (j = (int) block_defs_stack.length () - 1; j >= 0; j--) |
38635499 DN |
1512 | { |
1513 | tree name, var; | |
b8698a0f | 1514 | |
9771b263 | 1515 | name = block_defs_stack[j]; |
38635499 DN |
1516 | if (name == NULL_TREE) |
1517 | { | |
1518 | i++; | |
1519 | if (n > 0 && i > n) | |
1520 | break; | |
1521 | fprintf (file, "\nLevel %d\n", i); | |
1522 | continue; | |
1523 | } | |
1524 | ||
1525 | if (DECL_P (name)) | |
1526 | { | |
1527 | var = name; | |
1528 | name = NULL_TREE; | |
1529 | } | |
1530 | else | |
1531 | { | |
1532 | var = SSA_NAME_VAR (name); | |
1533 | if (!is_gimple_reg (var)) | |
1534 | { | |
1535 | j--; | |
9771b263 | 1536 | var = block_defs_stack[j]; |
38635499 DN |
1537 | } |
1538 | } | |
1539 | ||
1540 | fprintf (file, " Previous CURRDEF ("); | |
1541 | print_generic_expr (file, var, 0); | |
1542 | fprintf (file, ") = "); | |
1543 | if (name) | |
1544 | print_generic_expr (file, name, 0); | |
1545 | else | |
1546 | fprintf (file, "<NIL>"); | |
1547 | fprintf (file, "\n"); | |
1548 | } | |
1549 | } | |
1550 | ||
1551 | ||
1552 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1553 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1554 | dumped. New levels are created when the dominator tree traversal | |
1555 | used for renaming enters a new sub-tree. */ | |
1556 | ||
24e47c76 | 1557 | DEBUG_FUNCTION void |
38635499 DN |
1558 | debug_defs_stack (int n) |
1559 | { | |
1560 | dump_defs_stack (stderr, n); | |
1561 | } | |
1562 | ||
1563 | ||
1564 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1565 | ||
1566 | void | |
1567 | dump_currdefs (FILE *file) | |
1568 | { | |
13714310 | 1569 | unsigned i; |
38635499 DN |
1570 | tree var; |
1571 | ||
9771b263 | 1572 | if (symbols_to_rename.is_empty ()) |
13714310 RG |
1573 | return; |
1574 | ||
38635499 | 1575 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
9771b263 | 1576 | FOR_EACH_VEC_ELT (symbols_to_rename, i, var) |
13714310 | 1577 | { |
526ceb68 | 1578 | common_info *info = get_common_info (var); |
13714310 RG |
1579 | fprintf (file, "CURRDEF ("); |
1580 | print_generic_expr (file, var, 0); | |
1581 | fprintf (file, ") = "); | |
8812aab1 RG |
1582 | if (info->current_def) |
1583 | print_generic_expr (file, info->current_def, 0); | |
13714310 RG |
1584 | else |
1585 | fprintf (file, "<NIL>"); | |
1586 | fprintf (file, "\n"); | |
1587 | } | |
38635499 DN |
1588 | } |
1589 | ||
1590 | ||
1591 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1592 | ||
24e47c76 | 1593 | DEBUG_FUNCTION void |
38635499 DN |
1594 | debug_currdefs (void) |
1595 | { | |
1596 | dump_currdefs (stderr); | |
1597 | } | |
1598 | ||
1599 | ||
6de9cd9a DN |
1600 | /* Dump SSA information to FILE. */ |
1601 | ||
1602 | void | |
1603 | dump_tree_ssa (FILE *file) | |
1604 | { | |
6de9cd9a | 1605 | const char *funcname |
673fda6b | 1606 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1607 | |
38635499 | 1608 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1609 | |
b4e209fd | 1610 | dump_var_infos (file); |
38635499 DN |
1611 | dump_defs_stack (file, -1); |
1612 | dump_currdefs (file); | |
1613 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1614 | } |
1615 | ||
1616 | ||
1617 | /* Dump SSA information to stderr. */ | |
1618 | ||
24e47c76 | 1619 | DEBUG_FUNCTION void |
6de9cd9a DN |
1620 | debug_tree_ssa (void) |
1621 | { | |
1622 | dump_tree_ssa (stderr); | |
1623 | } | |
1624 | ||
1625 | ||
7256233c DN |
1626 | /* Dump statistics for the hash table HTAB. */ |
1627 | ||
1628 | static void | |
c203e8a7 | 1629 | htab_statistics (FILE *file, const hash_table<var_info_hasher> &htab) |
7256233c DN |
1630 | { |
1631 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
bf190e8d LC |
1632 | (long) htab.size (), |
1633 | (long) htab.elements (), | |
1634 | htab.collisions ()); | |
7256233c DN |
1635 | } |
1636 | ||
1637 | ||
6de9cd9a DN |
1638 | /* Dump SSA statistics on FILE. */ |
1639 | ||
1640 | void | |
1641 | dump_tree_ssa_stats (FILE *file) | |
1642 | { | |
c203e8a7 | 1643 | if (var_infos) |
38635499 | 1644 | { |
b4e209fd RG |
1645 | fprintf (file, "\nHash table statistics:\n"); |
1646 | fprintf (file, " var_infos: "); | |
c203e8a7 | 1647 | htab_statistics (file, *var_infos); |
b4e209fd | 1648 | fprintf (file, "\n"); |
38635499 | 1649 | } |
6de9cd9a DN |
1650 | } |
1651 | ||
1652 | ||
1653 | /* Dump SSA statistics on stderr. */ | |
1654 | ||
24e47c76 | 1655 | DEBUG_FUNCTION void |
6de9cd9a DN |
1656 | debug_tree_ssa_stats (void) |
1657 | { | |
1658 | dump_tree_ssa_stats (stderr); | |
1659 | } | |
1660 | ||
1661 | ||
b4e209fd | 1662 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
6de9cd9a | 1663 | |
bf190e8d | 1664 | int |
526ceb68 | 1665 | debug_var_infos_r (var_info **slot, FILE *file) |
7256233c | 1666 | { |
526ceb68 | 1667 | var_info *info = *slot; |
b8698a0f | 1668 | |
38635499 | 1669 | fprintf (file, "VAR: "); |
8812aab1 RG |
1670 | print_generic_expr (file, info->var, dump_flags); |
1671 | bitmap_print (file, info->info.def_blocks.def_blocks, | |
1672 | ", DEF_BLOCKS: { ", "}"); | |
1673 | bitmap_print (file, info->info.def_blocks.livein_blocks, | |
1674 | ", LIVEIN_BLOCKS: { ", "}"); | |
1675 | bitmap_print (file, info->info.def_blocks.phi_blocks, | |
1676 | ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1677 | |
7256233c DN |
1678 | return 1; |
1679 | } | |
6de9cd9a | 1680 | |
6de9cd9a | 1681 | |
b4e209fd | 1682 | /* Dump the VAR_INFOS hash table on FILE. */ |
38635499 DN |
1683 | |
1684 | void | |
b4e209fd | 1685 | dump_var_infos (FILE *file) |
38635499 DN |
1686 | { |
1687 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
c203e8a7 TS |
1688 | if (var_infos) |
1689 | var_infos->traverse <FILE *, debug_var_infos_r> (file); | |
38635499 DN |
1690 | } |
1691 | ||
1692 | ||
b4e209fd | 1693 | /* Dump the VAR_INFOS hash table on stderr. */ |
6de9cd9a | 1694 | |
24e47c76 | 1695 | DEBUG_FUNCTION void |
b4e209fd | 1696 | debug_var_infos (void) |
7256233c | 1697 | { |
b4e209fd | 1698 | dump_var_infos (stderr); |
7256233c | 1699 | } |
6de9cd9a | 1700 | |
5f240ec4 | 1701 | |
0bca51f0 | 1702 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1703 | |
0bca51f0 DN |
1704 | static inline void |
1705 | register_new_update_single (tree new_name, tree old_name) | |
1706 | { | |
526ceb68 | 1707 | common_info *info = get_common_info (old_name); |
8812aab1 | 1708 | tree currdef = info->current_def; |
5f240ec4 | 1709 | |
38635499 | 1710 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1711 | This stack is later used by the dominator tree callbacks to |
1712 | restore the reaching definitions for all the variables | |
1713 | defined in the block after a recursive visit to all its | |
1714 | immediately dominated blocks. */ | |
9771b263 DN |
1715 | block_defs_stack.reserve (2); |
1716 | block_defs_stack.quick_push (currdef); | |
1717 | block_defs_stack.quick_push (old_name); | |
5f240ec4 | 1718 | |
0bca51f0 DN |
1719 | /* Set the current reaching definition for OLD_NAME to be |
1720 | NEW_NAME. */ | |
8812aab1 | 1721 | info->current_def = new_name; |
0bca51f0 | 1722 | } |
7256233c | 1723 | |
6de9cd9a | 1724 | |
0bca51f0 DN |
1725 | /* Register NEW_NAME to be the new reaching definition for all the |
1726 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1727 | replace old SSA names with new ones. */ | |
7256233c | 1728 | |
0bca51f0 DN |
1729 | static inline void |
1730 | register_new_update_set (tree new_name, bitmap old_names) | |
1731 | { | |
1732 | bitmap_iterator bi; | |
1733 | unsigned i; | |
7256233c | 1734 | |
0bca51f0 DN |
1735 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1736 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1737 | } |
1738 | ||
7256233c | 1739 | |
0bca51f0 | 1740 | |
84d65814 DN |
1741 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1742 | it is a symbol marked for renaming, replace it with USE_P's current | |
1743 | reaching definition. */ | |
1744 | ||
1745 | static inline void | |
1746 | maybe_replace_use (use_operand_p use_p) | |
1747 | { | |
1748 | tree rdef = NULL_TREE; | |
1749 | tree use = USE_FROM_PTR (use_p); | |
1750 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1751 | ||
13714310 | 1752 | if (marked_for_renaming (sym)) |
84d65814 DN |
1753 | rdef = get_reaching_def (sym); |
1754 | else if (is_old_name (use)) | |
1755 | rdef = get_reaching_def (use); | |
1756 | ||
1757 | if (rdef && rdef != use) | |
1758 | SET_USE (use_p, rdef); | |
1759 | } | |
1760 | ||
1761 | ||
b5b8b0ac AO |
1762 | /* Same as maybe_replace_use, but without introducing default stmts, |
1763 | returning false to indicate a need to do so. */ | |
1764 | ||
1765 | static inline bool | |
1766 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1767 | { | |
1768 | tree rdef = NULL_TREE; | |
1769 | tree use = USE_FROM_PTR (use_p); | |
1770 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1771 | ||
13714310 | 1772 | if (marked_for_renaming (sym)) |
8812aab1 | 1773 | rdef = get_var_info (sym)->info.current_def; |
b5b8b0ac AO |
1774 | else if (is_old_name (use)) |
1775 | { | |
8812aab1 | 1776 | rdef = get_ssa_name_ann (use)->info.current_def; |
b5b8b0ac AO |
1777 | /* We can't assume that, if there's no current definition, the |
1778 | default one should be used. It could be the case that we've | |
1779 | rearranged blocks so that the earlier definition no longer | |
1780 | dominates the use. */ | |
1781 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1782 | rdef = use; | |
1783 | } | |
1784 | else | |
1785 | rdef = use; | |
1786 | ||
1787 | if (rdef && rdef != use) | |
1788 | SET_USE (use_p, rdef); | |
1789 | ||
1790 | return rdef != NULL_TREE; | |
1791 | } | |
1792 | ||
1793 | ||
84d65814 DN |
1794 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1795 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1796 | register it as the current definition for the names replaced by | |
956623c1 | 1797 | DEF_P. Returns whether the statement should be removed. */ |
84d65814 | 1798 | |
956623c1 | 1799 | static inline bool |
355fe088 | 1800 | maybe_register_def (def_operand_p def_p, gimple *stmt, |
3a56edc7 | 1801 | gimple_stmt_iterator gsi) |
84d65814 DN |
1802 | { |
1803 | tree def = DEF_FROM_PTR (def_p); | |
1804 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
956623c1 | 1805 | bool to_delete = false; |
84d65814 | 1806 | |
38635499 DN |
1807 | /* If DEF is a naked symbol that needs renaming, create a new |
1808 | name for it. */ | |
13714310 | 1809 | if (marked_for_renaming (sym)) |
84d65814 DN |
1810 | { |
1811 | if (DECL_P (def)) | |
1812 | { | |
956623c1 MG |
1813 | if (gimple_clobber_p (stmt) && is_gimple_reg (sym)) |
1814 | { | |
1815 | gcc_checking_assert (TREE_CODE (sym) == VAR_DECL); | |
1816 | /* Replace clobber stmts with a default def. This new use of a | |
1817 | default definition may make it look like SSA_NAMEs have | |
1818 | conflicting lifetimes, so we need special code to let them | |
1819 | coalesce properly. */ | |
1820 | to_delete = true; | |
1821 | def = get_or_create_ssa_default_def (cfun, sym); | |
1822 | } | |
1823 | else | |
1824 | def = make_ssa_name (def, stmt); | |
84d65814 | 1825 | SET_DEF (def_p, def); |
3a56edc7 | 1826 | |
956623c1 | 1827 | tree tracked_var = target_for_debug_bind (sym); |
3a56edc7 AO |
1828 | if (tracked_var) |
1829 | { | |
355fe088 | 1830 | gimple *note = gimple_build_debug_bind (tracked_var, def, stmt); |
c47987fa JJ |
1831 | /* If stmt ends the bb, insert the debug stmt on the single |
1832 | non-EH edge from the stmt. */ | |
1833 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1834 | { | |
1835 | basic_block bb = gsi_bb (gsi); | |
1836 | edge_iterator ei; | |
1837 | edge e, ef = NULL; | |
1838 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1839 | if (!(e->flags & EDGE_EH)) | |
1840 | { | |
4ad14919 | 1841 | gcc_checking_assert (!ef); |
c47987fa JJ |
1842 | ef = e; |
1843 | } | |
23d5ed5d AO |
1844 | /* If there are other predecessors to ef->dest, then |
1845 | there must be PHI nodes for the modified | |
1846 | variable, and therefore there will be debug bind | |
1847 | stmts after the PHI nodes. The debug bind notes | |
1848 | we'd insert would force the creation of a new | |
1849 | block (diverging codegen) and be redundant with | |
1850 | the post-PHI bind stmts, so don't add them. | |
1851 | ||
1852 | As for the exit edge, there wouldn't be redundant | |
1853 | bind stmts, but there wouldn't be a PC to bind | |
1854 | them to either, so avoid diverging the CFG. */ | |
1855 | if (ef && single_pred_p (ef->dest) | |
fefa31b5 | 1856 | && ef->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
23d5ed5d AO |
1857 | { |
1858 | /* If there were PHI nodes in the node, we'd | |
1859 | have to make sure the value we're binding | |
1860 | doesn't need rewriting. But there shouldn't | |
1861 | be PHI nodes in a single-predecessor block, | |
1862 | so we just add the note. */ | |
1863 | gsi_insert_on_edge_immediate (ef, note); | |
1864 | } | |
c47987fa JJ |
1865 | } |
1866 | else | |
1867 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
3a56edc7 | 1868 | } |
84d65814 DN |
1869 | } |
1870 | ||
1871 | register_new_update_single (def, sym); | |
1872 | } | |
1873 | else | |
1874 | { | |
1875 | /* If DEF is a new name, register it as a new definition | |
1876 | for all the names replaced by DEF. */ | |
1877 | if (is_new_name (def)) | |
1878 | register_new_update_set (def, names_replaced_by (def)); | |
1879 | ||
1880 | /* If DEF is an old name, register DEF as a new | |
1881 | definition for itself. */ | |
1882 | if (is_old_name (def)) | |
1883 | register_new_update_single (def, def); | |
1884 | } | |
956623c1 MG |
1885 | |
1886 | return to_delete; | |
84d65814 DN |
1887 | } |
1888 | ||
1889 | ||
0bca51f0 DN |
1890 | /* Update every variable used in the statement pointed-to by SI. The |
1891 | statement is assumed to be in SSA form already. Names in | |
1892 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1893 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1894 | will be registered as a new definition for their corresponding name | |
956623c1 | 1895 | in OLD_SSA_NAMES. Returns whether STMT should be removed. */ |
0bca51f0 | 1896 | |
956623c1 | 1897 | static bool |
355fe088 | 1898 | rewrite_update_stmt (gimple *stmt, gimple_stmt_iterator gsi) |
0bca51f0 | 1899 | { |
0bca51f0 DN |
1900 | use_operand_p use_p; |
1901 | def_operand_p def_p; | |
1902 | ssa_op_iter iter; | |
1903 | ||
0bca51f0 | 1904 | /* Only update marked statements. */ |
726a989a | 1905 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
956623c1 | 1906 | return false; |
0bca51f0 DN |
1907 | |
1908 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1909 | { | |
1910 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 1911 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
1912 | } |
1913 | ||
1914 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1915 | symbol is marked for renaming. */ | |
726a989a | 1916 | if (rewrite_uses_p (stmt)) |
b5b8b0ac AO |
1917 | { |
1918 | if (is_gimple_debug (stmt)) | |
1919 | { | |
1920 | bool failed = false; | |
1921 | ||
1922 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1923 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
1924 | { | |
1925 | failed = true; | |
1926 | break; | |
1927 | } | |
1928 | ||
1929 | if (failed) | |
1930 | { | |
1931 | /* DOM sometimes threads jumps in such a way that a | |
1932 | debug stmt ends up referencing a SSA variable that no | |
1933 | longer dominates the debug stmt, but such that all | |
1934 | incoming definitions refer to the same definition in | |
1935 | an earlier dominator. We could try to recover that | |
1936 | definition somehow, but this will have to do for now. | |
1937 | ||
1938 | Introducing a default definition, which is what | |
1939 | maybe_replace_use() would do in such cases, may | |
1940 | modify code generation, for the otherwise-unused | |
1941 | default definition would never go away, modifying SSA | |
1942 | version numbers all over. */ | |
1943 | gimple_debug_bind_reset_value (stmt); | |
1944 | update_stmt (stmt); | |
1945 | } | |
1946 | } | |
1947 | else | |
1948 | { | |
1949 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
1950 | maybe_replace_use (use_p); | |
1951 | } | |
1952 | } | |
0bca51f0 DN |
1953 | |
1954 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
1955 | Also register definitions for names whose underlying symbol is | |
1956 | marked for renaming. */ | |
956623c1 | 1957 | bool to_delete = false; |
726a989a | 1958 | if (register_defs_p (stmt)) |
5006671f | 1959 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
956623c1 MG |
1960 | to_delete |= maybe_register_def (def_p, stmt, gsi); |
1961 | ||
1962 | return to_delete; | |
0bca51f0 DN |
1963 | } |
1964 | ||
1965 | ||
1966 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
1967 | every PHI node found, check if any of its arguments is in | |
1968 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
1969 | definition, replace it. */ | |
1970 | ||
1971 | static void | |
ccf5c864 | 1972 | rewrite_update_phi_arguments (basic_block bb) |
0bca51f0 DN |
1973 | { |
1974 | edge e; | |
1975 | edge_iterator ei; | |
2ce79879 | 1976 | unsigned i; |
0bca51f0 DN |
1977 | |
1978 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1979 | { | |
538dd0b7 DM |
1980 | gphi *phi; |
1981 | vec<gphi *> phis; | |
0bca51f0 | 1982 | |
2ce79879 ZD |
1983 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
1984 | continue; | |
b8698a0f | 1985 | |
9771b263 DN |
1986 | phis = phis_to_rewrite[e->dest->index]; |
1987 | FOR_EACH_VEC_ELT (phis, i, phi) | |
0bca51f0 | 1988 | { |
f5045c96 | 1989 | tree arg, lhs_sym, reaching_def = NULL; |
0bca51f0 DN |
1990 | use_operand_p arg_p; |
1991 | ||
4ad14919 | 1992 | gcc_checking_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
1993 | |
1994 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
1995 | arg = USE_FROM_PTR (arg_p); | |
1996 | ||
1997 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
1998 | continue; | |
1999 | ||
726a989a | 2000 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 2001 | |
0bca51f0 DN |
2002 | if (arg == NULL_TREE) |
2003 | { | |
2004 | /* When updating a PHI node for a recently introduced | |
2005 | symbol we may find NULL arguments. That's why we | |
2006 | take the symbol from the LHS of the PHI node. */ | |
f5045c96 AM |
2007 | reaching_def = get_reaching_def (lhs_sym); |
2008 | ||
0bca51f0 DN |
2009 | } |
2010 | else | |
2011 | { | |
2012 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2013 | ||
13714310 | 2014 | if (marked_for_renaming (sym)) |
f5045c96 | 2015 | reaching_def = get_reaching_def (sym); |
0bca51f0 | 2016 | else if (is_old_name (arg)) |
f5045c96 AM |
2017 | reaching_def = get_reaching_def (arg); |
2018 | } | |
2019 | ||
2020 | /* Update the argument if there is a reaching def. */ | |
2021 | if (reaching_def) | |
2022 | { | |
f5045c96 AM |
2023 | source_location locus; |
2024 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2025 | ||
2026 | SET_USE (arg_p, reaching_def); | |
f5045c96 | 2027 | |
ffc5b2bb RB |
2028 | /* Virtual operands do not need a location. */ |
2029 | if (virtual_operand_p (reaching_def)) | |
2030 | locus = UNKNOWN_LOCATION; | |
f5045c96 | 2031 | else |
ffc5b2bb | 2032 | { |
355fe088 | 2033 | gimple *stmt = SSA_NAME_DEF_STMT (reaching_def); |
538dd0b7 | 2034 | gphi *other_phi = dyn_cast <gphi *> (stmt); |
ffc5b2bb RB |
2035 | |
2036 | /* Single element PHI nodes behave like copies, so get the | |
2037 | location from the phi argument. */ | |
538dd0b7 DM |
2038 | if (other_phi |
2039 | && gimple_phi_num_args (other_phi) == 1) | |
2040 | locus = gimple_phi_arg_location (other_phi, 0); | |
ffc5b2bb RB |
2041 | else |
2042 | locus = gimple_location (stmt); | |
2043 | } | |
f5045c96 AM |
2044 | |
2045 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
0bca51f0 DN |
2046 | } |
2047 | ||
f5045c96 | 2048 | |
0bca51f0 DN |
2049 | if (e->flags & EDGE_ABNORMAL) |
2050 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2051 | } | |
2052 | } | |
2053 | } | |
2054 | ||
4d9192b5 TS |
2055 | class rewrite_update_dom_walker : public dom_walker |
2056 | { | |
2057 | public: | |
2058 | rewrite_update_dom_walker (cdi_direction direction) : dom_walker (direction) {} | |
2059 | ||
3daacdcd | 2060 | virtual edge before_dom_children (basic_block); |
4d9192b5 TS |
2061 | virtual void after_dom_children (basic_block); |
2062 | }; | |
0bca51f0 | 2063 | |
ccf5c864 PB |
2064 | /* Initialization of block data structures for the incremental SSA |
2065 | update pass. Create a block local stack of reaching definitions | |
2066 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2067 | new definitions for every PHI node in the block. */ | |
2068 | ||
3daacdcd | 2069 | edge |
4d9192b5 | 2070 | rewrite_update_dom_walker::before_dom_children (basic_block bb) |
ccf5c864 | 2071 | { |
ccf5c864 | 2072 | bool is_abnormal_phi; |
ccf5c864 PB |
2073 | |
2074 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
427f99e2 | 2075 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
ccf5c864 PB |
2076 | bb->index); |
2077 | ||
2078 | /* Mark the unwind point for this block. */ | |
9771b263 | 2079 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
2080 | |
2081 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
3daacdcd | 2082 | return NULL; |
ccf5c864 PB |
2083 | |
2084 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2085 | edge. */ | |
31ff2426 | 2086 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
ccf5c864 PB |
2087 | |
2088 | /* If any of the PHI nodes is a replacement for a name in | |
2089 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2090 | register it as a new definition for its corresponding name. Also | |
2091 | register definitions for names whose underlying symbols are | |
2092 | marked for renaming. */ | |
538dd0b7 DM |
2093 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
2094 | gsi_next (&gsi)) | |
ccf5c864 PB |
2095 | { |
2096 | tree lhs, lhs_sym; | |
538dd0b7 | 2097 | gphi *phi = gsi.phi (); |
ccf5c864 PB |
2098 | |
2099 | if (!register_defs_p (phi)) | |
2100 | continue; | |
b8698a0f | 2101 | |
ccf5c864 PB |
2102 | lhs = gimple_phi_result (phi); |
2103 | lhs_sym = SSA_NAME_VAR (lhs); | |
2104 | ||
13714310 | 2105 | if (marked_for_renaming (lhs_sym)) |
ccf5c864 PB |
2106 | register_new_update_single (lhs, lhs_sym); |
2107 | else | |
2108 | { | |
2109 | ||
2110 | /* If LHS is a new name, register a new definition for all | |
2111 | the names replaced by LHS. */ | |
2112 | if (is_new_name (lhs)) | |
2113 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
b8698a0f | 2114 | |
ccf5c864 PB |
2115 | /* If LHS is an OLD name, register it as a new definition |
2116 | for itself. */ | |
2117 | if (is_old_name (lhs)) | |
2118 | register_new_update_single (lhs, lhs); | |
2119 | } | |
2120 | ||
2121 | if (is_abnormal_phi) | |
2122 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2123 | } | |
2124 | ||
2125 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
d7c028c0 | 2126 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
3a56edc7 | 2127 | { |
4ad14919 | 2128 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
538dd0b7 | 2129 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) |
956623c1 MG |
2130 | if (rewrite_update_stmt (gsi_stmt (gsi), gsi)) |
2131 | gsi_remove (&gsi, true); | |
2132 | else | |
2133 | gsi_next (&gsi); | |
3a56edc7 | 2134 | } |
ccf5c864 PB |
2135 | |
2136 | /* Step 3. Update PHI nodes. */ | |
2137 | rewrite_update_phi_arguments (bb); | |
3daacdcd JL |
2138 | |
2139 | return NULL; | |
ccf5c864 PB |
2140 | } |
2141 | ||
2142 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2143 | the current reaching definition of every name re-written in BB to | |
2144 | the original reaching definition before visiting BB. This | |
2145 | unwinding must be done in the opposite order to what is done in | |
2146 | register_new_update_set. */ | |
2147 | ||
4d9192b5 TS |
2148 | void |
2149 | rewrite_update_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
ccf5c864 | 2150 | { |
9771b263 | 2151 | while (block_defs_stack.length () > 0) |
ccf5c864 | 2152 | { |
9771b263 | 2153 | tree var = block_defs_stack.pop (); |
ccf5c864 | 2154 | tree saved_def; |
b8698a0f | 2155 | |
ccf5c864 PB |
2156 | /* NULL indicates the unwind stop point for this block (see |
2157 | rewrite_update_enter_block). */ | |
2158 | if (var == NULL) | |
2159 | return; | |
2160 | ||
9771b263 | 2161 | saved_def = block_defs_stack.pop (); |
8812aab1 | 2162 | get_common_info (var)->current_def = saved_def; |
ccf5c864 PB |
2163 | } |
2164 | } | |
2165 | ||
2166 | ||
0bca51f0 | 2167 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
b8698a0f | 2168 | form. |
0bca51f0 DN |
2169 | |
2170 | ENTRY indicates the block where to start. Every block dominated by | |
2171 | ENTRY will be rewritten. | |
2172 | ||
2173 | WHAT indicates what actions will be taken by the renamer (see enum | |
2174 | rewrite_mode). | |
2175 | ||
2176 | BLOCKS are the set of interesting blocks for the dominator walker | |
2177 | to process. If this set is NULL, then all the nodes dominated | |
2178 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2179 | are not present in BLOCKS are ignored. */ | |
2180 | ||
2181 | static void | |
ccf5c864 | 2182 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
0bca51f0 | 2183 | { |
0bca51f0 DN |
2184 | /* Rewrite all the basic blocks in the program. */ |
2185 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2186 | ||
4d9192b5 | 2187 | block_defs_stack.create (10); |
0bca51f0 | 2188 | |
4d9192b5 TS |
2189 | /* Recursively walk the dominator tree rewriting each statement in |
2190 | each basic block. */ | |
0bca51f0 | 2191 | if (what == REWRITE_ALL) |
4d9192b5 | 2192 | rewrite_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 | 2193 | else if (what == REWRITE_UPDATE) |
4d9192b5 | 2194 | rewrite_update_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 DN |
2195 | else |
2196 | gcc_unreachable (); | |
2197 | ||
0bca51f0 DN |
2198 | /* Debugging dumps. */ |
2199 | if (dump_file && (dump_flags & TDF_STATS)) | |
2200 | { | |
2201 | dump_dfa_stats (dump_file); | |
c203e8a7 | 2202 | if (var_infos) |
0bca51f0 DN |
2203 | dump_tree_ssa_stats (dump_file); |
2204 | } | |
b8698a0f | 2205 | |
9771b263 | 2206 | block_defs_stack.release (); |
0bca51f0 DN |
2207 | |
2208 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2209 | } | |
2210 | ||
4d9192b5 | 2211 | class mark_def_dom_walker : public dom_walker |
7256233c | 2212 | { |
4d9192b5 TS |
2213 | public: |
2214 | mark_def_dom_walker (cdi_direction direction); | |
2215 | ~mark_def_dom_walker (); | |
5f240ec4 | 2216 | |
3daacdcd | 2217 | virtual edge before_dom_children (basic_block); |
5f240ec4 | 2218 | |
4d9192b5 | 2219 | private: |
7256233c DN |
2220 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2221 | large enough to accommodate all the variables referenced in the | |
2222 | function, not just the ones we are renaming. */ | |
65d3284b | 2223 | bitmap m_kills; |
4d9192b5 | 2224 | }; |
6de9cd9a | 2225 | |
4d9192b5 | 2226 | mark_def_dom_walker::mark_def_dom_walker (cdi_direction direction) |
65d3284b | 2227 | : dom_walker (direction), m_kills (BITMAP_ALLOC (NULL)) |
4d9192b5 TS |
2228 | { |
2229 | } | |
7256233c | 2230 | |
4d9192b5 TS |
2231 | mark_def_dom_walker::~mark_def_dom_walker () |
2232 | { | |
65d3284b | 2233 | BITMAP_FREE (m_kills); |
4d9192b5 | 2234 | } |
7256233c | 2235 | |
4d9192b5 TS |
2236 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2237 | at the start of each block, and call mark_def_sites for each statement. */ | |
7256233c | 2238 | |
3daacdcd | 2239 | edge |
4d9192b5 TS |
2240 | mark_def_dom_walker::before_dom_children (basic_block bb) |
2241 | { | |
2242 | gimple_stmt_iterator gsi; | |
7256233c | 2243 | |
65d3284b | 2244 | bitmap_clear (m_kills); |
4d9192b5 | 2245 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
65d3284b | 2246 | mark_def_sites (bb, gsi_stmt (gsi), m_kills); |
3daacdcd | 2247 | return NULL; |
6de9cd9a DN |
2248 | } |
2249 | ||
38635499 DN |
2250 | /* Initialize internal data needed during renaming. */ |
2251 | ||
2252 | static void | |
2253 | init_ssa_renamer (void) | |
2254 | { | |
38635499 DN |
2255 | cfun->gimple_df->in_ssa_p = false; |
2256 | ||
2257 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
c203e8a7 TS |
2258 | gcc_assert (!var_infos); |
2259 | var_infos = new hash_table<var_info_hasher> | |
2260 | (vec_safe_length (cfun->local_decls)); | |
38635499 | 2261 | |
b4e209fd | 2262 | bitmap_obstack_initialize (&update_ssa_obstack); |
38635499 DN |
2263 | } |
2264 | ||
2265 | ||
2266 | /* Deallocate internal data structures used by the renamer. */ | |
2267 | ||
2268 | static void | |
2269 | fini_ssa_renamer (void) | |
2270 | { | |
c203e8a7 TS |
2271 | delete var_infos; |
2272 | var_infos = NULL; | |
38635499 | 2273 | |
b4e209fd RG |
2274 | bitmap_obstack_release (&update_ssa_obstack); |
2275 | ||
13714310 RG |
2276 | cfun->gimple_df->ssa_renaming_needed = 0; |
2277 | cfun->gimple_df->rename_vops = 0; | |
38635499 DN |
2278 | cfun->gimple_df->in_ssa_p = true; |
2279 | } | |
2280 | ||
7256233c | 2281 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2282 | proceeds in four main phases: |
6de9cd9a | 2283 | |
0bca51f0 DN |
2284 | 1- Compute dominance frontier and immediate dominators, needed to |
2285 | insert PHI nodes and rename the function in dominator tree | |
2286 | order. | |
6de9cd9a | 2287 | |
4d9192b5 | 2288 | 2- Find and mark all the blocks that define variables. |
6de9cd9a | 2289 | |
0bca51f0 | 2290 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2291 | |
0bca51f0 | 2292 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2293 | |
77bfa778 | 2294 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2295 | (walk_dominator_tree). */ |
7256233c | 2296 | |
be55bfe6 TS |
2297 | namespace { |
2298 | ||
2299 | const pass_data pass_data_build_ssa = | |
2300 | { | |
2301 | GIMPLE_PASS, /* type */ | |
2302 | "ssa", /* name */ | |
2303 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
2304 | TV_TREE_SSA_OTHER, /* tv_id */ |
2305 | PROP_cfg, /* properties_required */ | |
2306 | PROP_ssa, /* properties_provided */ | |
2307 | 0, /* properties_destroyed */ | |
2308 | 0, /* todo_flags_start */ | |
3bea341f | 2309 | TODO_remove_unused_locals, /* todo_flags_finish */ |
be55bfe6 TS |
2310 | }; |
2311 | ||
2312 | class pass_build_ssa : public gimple_opt_pass | |
2313 | { | |
2314 | public: | |
2315 | pass_build_ssa (gcc::context *ctxt) | |
2316 | : gimple_opt_pass (pass_data_build_ssa, ctxt) | |
2317 | {} | |
2318 | ||
2319 | /* opt_pass methods: */ | |
2320 | virtual bool gate (function *fun) | |
2321 | { | |
2322 | /* Do nothing for funcions that was produced already in SSA form. */ | |
2323 | return !(fun->curr_properties & PROP_ssa); | |
2324 | } | |
2325 | ||
2326 | virtual unsigned int execute (function *); | |
2327 | ||
2328 | }; // class pass_build_ssa | |
2329 | ||
2330 | unsigned int | |
2331 | pass_build_ssa::execute (function *fun) | |
6de9cd9a | 2332 | { |
0fc555fb | 2333 | bitmap_head *dfs; |
7256233c | 2334 | basic_block bb; |
70b5e7dc | 2335 | unsigned i; |
b8698a0f | 2336 | |
0bca51f0 | 2337 | /* Initialize operand data structures. */ |
be55bfe6 | 2338 | init_ssa_operands (fun); |
6de9cd9a | 2339 | |
38635499 DN |
2340 | /* Initialize internal data needed by the renamer. */ |
2341 | init_ssa_renamer (); | |
2342 | ||
0bca51f0 DN |
2343 | /* Initialize the set of interesting blocks. The callback |
2344 | mark_def_sites will add to this set those blocks that the renamer | |
2345 | should process. */ | |
be55bfe6 | 2346 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (fun)); |
f61e445a | 2347 | bitmap_clear (interesting_blocks); |
6de9cd9a | 2348 | |
af5d3a18 | 2349 | /* Initialize dominance frontier. */ |
be55bfe6 TS |
2350 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (fun)); |
2351 | FOR_EACH_BB_FN (bb, fun) | |
0fc555fb | 2352 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
6de9cd9a | 2353 | |
0bca51f0 DN |
2354 | /* 1- Compute dominance frontiers. */ |
2355 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2356 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2357 | |
0bca51f0 | 2358 | /* 2- Find and mark definition sites. */ |
be55bfe6 | 2359 | mark_def_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr); |
0bca51f0 DN |
2360 | |
2361 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2362 | insert_phi_nodes (dfs); |
6de9cd9a | 2363 | |
0bca51f0 | 2364 | /* 4- Rename all the blocks. */ |
be55bfe6 | 2365 | rewrite_blocks (ENTRY_BLOCK_PTR_FOR_FN (fun), REWRITE_ALL); |
6de9cd9a | 2366 | |
7256233c | 2367 | /* Free allocated memory. */ |
be55bfe6 | 2368 | FOR_EACH_BB_FN (bb, fun) |
0fc555fb | 2369 | bitmap_clear (&dfs[bb->index]); |
7256233c | 2370 | free (dfs); |
6de9cd9a | 2371 | |
b5dcb2b9 JL |
2372 | sbitmap_free (interesting_blocks); |
2373 | ||
38635499 DN |
2374 | fini_ssa_renamer (); |
2375 | ||
70b5e7dc RG |
2376 | /* Try to get rid of all gimplifier generated temporaries by making |
2377 | its SSA names anonymous. This way we can garbage collect them | |
2378 | all after removing unused locals which we do in our TODO. */ | |
2379 | for (i = 1; i < num_ssa_names; ++i) | |
2380 | { | |
2381 | tree decl, name = ssa_name (i); | |
2382 | if (!name | |
2383 | || SSA_NAME_IS_DEFAULT_DEF (name)) | |
2384 | continue; | |
2385 | decl = SSA_NAME_VAR (name); | |
2386 | if (decl | |
2387 | && TREE_CODE (decl) == VAR_DECL | |
2388 | && !VAR_DECL_IS_VIRTUAL_OPERAND (decl) | |
74fc8b8a RB |
2389 | && DECL_IGNORED_P (decl)) |
2390 | SET_SSA_NAME_VAR_OR_IDENTIFIER (name, DECL_NAME (decl)); | |
70b5e7dc RG |
2391 | } |
2392 | ||
c2924966 | 2393 | return 0; |
6de9cd9a DN |
2394 | } |
2395 | ||
27a4cd48 DM |
2396 | } // anon namespace |
2397 | ||
2398 | gimple_opt_pass * | |
2399 | make_pass_build_ssa (gcc::context *ctxt) | |
2400 | { | |
2401 | return new pass_build_ssa (ctxt); | |
2402 | } | |
2403 | ||
6de9cd9a | 2404 | |
0bca51f0 DN |
2405 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2406 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2407 | |
0bca51f0 | 2408 | static void |
355fe088 TS |
2409 | mark_def_interesting (tree var, gimple *stmt, basic_block bb, |
2410 | bool insert_phi_p) | |
6de9cd9a | 2411 | { |
4ad14919 | 2412 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2413 | set_register_defs (stmt, true); |
0bca51f0 DN |
2414 | |
2415 | if (insert_phi_p) | |
2416 | { | |
726a989a | 2417 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2418 | |
0bca51f0 DN |
2419 | set_def_block (var, bb, is_phi_p); |
2420 | ||
2421 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2422 | site for both itself and all the old names replaced by it. */ | |
2423 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2424 | { | |
2425 | bitmap_iterator bi; | |
2426 | unsigned i; | |
2427 | bitmap set = names_replaced_by (var); | |
2428 | if (set) | |
2429 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2430 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2431 | } | |
2432 | } | |
2433 | } | |
2434 | ||
2435 | ||
2436 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2437 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2438 | nodes. */ |
0bca51f0 DN |
2439 | |
2440 | static inline void | |
355fe088 TS |
2441 | mark_use_interesting (tree var, gimple *stmt, basic_block bb, |
2442 | bool insert_phi_p) | |
0bca51f0 | 2443 | { |
726a989a | 2444 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2445 | |
95dd3097 ZD |
2446 | mark_block_for_update (def_bb); |
2447 | mark_block_for_update (bb); | |
2448 | ||
726a989a | 2449 | if (gimple_code (stmt) == GIMPLE_PHI) |
538dd0b7 | 2450 | mark_phi_for_rewrite (def_bb, as_a <gphi *> (stmt)); |
2ce79879 | 2451 | else |
b5b8b0ac AO |
2452 | { |
2453 | set_rewrite_uses (stmt, true); | |
2454 | ||
2455 | if (is_gimple_debug (stmt)) | |
2456 | return; | |
2457 | } | |
0bca51f0 DN |
2458 | |
2459 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2460 | to BB. Note that we cannot just use the block holding VAR's | |
2461 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2462 | it will have several definitions (itself and all the names that | |
2463 | replace it). */ | |
2464 | if (insert_phi_p) | |
2465 | { | |
526ceb68 | 2466 | def_blocks *db_p = get_def_blocks_for (get_common_info (var)); |
0bca51f0 DN |
2467 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2468 | set_livein_block (var, bb); | |
2469 | } | |
2470 | } | |
2471 | ||
2472 | ||
0bca51f0 | 2473 | /* Do a dominator walk starting at BB processing statements that |
13714310 | 2474 | reference symbols in SSA operands. This is very similar to |
84d65814 | 2475 | mark_def_sites, but the scan handles statements whose operands may |
95dd3097 | 2476 | already be SSA names. |
0bca51f0 | 2477 | |
84d65814 DN |
2478 | If INSERT_PHI_P is true, mark those uses as live in the |
2479 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2480 | algorithm to make PHI pruning decisions. |
2481 | ||
2482 | FIXME. Most of this would be unnecessary if we could associate a | |
2483 | symbol to all the SSA names that reference it. But that | |
2484 | sounds like it would be expensive to maintain. Still, it | |
2485 | would be interesting to see if it makes better sense to do | |
2486 | that. */ | |
0bca51f0 DN |
2487 | |
2488 | static void | |
95dd3097 | 2489 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2490 | { |
2491 | basic_block son; | |
f074ff6c ZD |
2492 | edge e; |
2493 | edge_iterator ei; | |
0bca51f0 | 2494 | |
95dd3097 ZD |
2495 | mark_block_for_update (bb); |
2496 | ||
0bca51f0 | 2497 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2498 | the symbols that we are interested in. */ |
538dd0b7 DM |
2499 | for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); |
2500 | gsi_next (&si)) | |
0bca51f0 | 2501 | { |
538dd0b7 | 2502 | gphi *phi = si.phi (); |
726a989a | 2503 | tree lhs_sym, lhs = gimple_phi_result (phi); |
0bca51f0 | 2504 | |
13714310 | 2505 | if (TREE_CODE (lhs) == SSA_NAME |
a471762f RG |
2506 | && (! virtual_operand_p (lhs) |
2507 | || ! cfun->gimple_df->rename_vops)) | |
f074ff6c | 2508 | continue; |
726a989a | 2509 | |
a471762f | 2510 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
13714310 | 2511 | mark_for_renaming (lhs_sym); |
f074ff6c ZD |
2512 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2513 | ||
2514 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2515 | to process the arguments of the phi nodes of the successor edges of | |
2516 | BB at the end of prepare_block_for_update, however, that turns out | |
2517 | to be significantly more expensive. Doing it here is conservatively | |
2518 | correct -- it may only cause us to believe a value to be live in a | |
2519 | block that also contains its definition, and thus insert a few more | |
2520 | phi nodes for it. */ | |
2521 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2522 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2523 | } |
2524 | ||
2525 | /* Process the statements. */ | |
538dd0b7 DM |
2526 | for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); |
2527 | gsi_next (&si)) | |
0bca51f0 | 2528 | { |
355fe088 | 2529 | gimple *stmt; |
0bca51f0 DN |
2530 | ssa_op_iter i; |
2531 | use_operand_p use_p; | |
2532 | def_operand_p def_p; | |
b8698a0f | 2533 | |
726a989a | 2534 | stmt = gsi_stmt (si); |
0bca51f0 | 2535 | |
13714310 RG |
2536 | if (cfun->gimple_df->rename_vops |
2537 | && gimple_vuse (stmt)) | |
0bca51f0 | 2538 | { |
13714310 | 2539 | tree use = gimple_vuse (stmt); |
0bca51f0 | 2540 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
13714310 RG |
2541 | mark_for_renaming (sym); |
2542 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2543 | } |
2544 | ||
13714310 | 2545 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
0bca51f0 | 2546 | { |
13714310 RG |
2547 | tree use = USE_FROM_PTR (use_p); |
2548 | if (!DECL_P (use)) | |
2549 | continue; | |
2550 | mark_for_renaming (use); | |
2551 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2552 | } | |
2553 | ||
2554 | if (cfun->gimple_df->rename_vops | |
2555 | && gimple_vdef (stmt)) | |
2556 | { | |
2557 | tree def = gimple_vdef (stmt); | |
0bca51f0 | 2558 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
13714310 RG |
2559 | mark_for_renaming (sym); |
2560 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2561 | } | |
2562 | ||
2563 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2564 | { | |
2565 | tree def = DEF_FROM_PTR (def_p); | |
2566 | if (!DECL_P (def)) | |
2567 | continue; | |
2568 | mark_for_renaming (def); | |
2569 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2570 | } |
2571 | } | |
2572 | ||
2573 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2574 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2575 | son; |
2576 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2577 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2578 | } |
2579 | ||
2580 | ||
2581 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2582 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2583 | prepare_names_to_update. */ | |
2584 | ||
2585 | static void | |
95dd3097 | 2586 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2587 | { |
2588 | use_operand_p use_p; | |
2589 | imm_use_iterator iter; | |
2590 | ||
2591 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2592 | { | |
355fe088 | 2593 | gimple *stmt = USE_STMT (use_p); |
726a989a | 2594 | basic_block bb = gimple_bb (stmt); |
84d65814 | 2595 | |
726a989a | 2596 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2597 | { |
f074ff6c | 2598 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
538dd0b7 | 2599 | edge e = gimple_phi_arg_edge (as_a <gphi *> (stmt), ix); |
f074ff6c | 2600 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2601 | } |
2602 | else | |
2603 | { | |
2604 | /* For regular statements, mark this as an interesting use | |
2605 | for NAME. */ | |
95dd3097 | 2606 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2607 | } |
2608 | } | |
0bca51f0 DN |
2609 | } |
2610 | ||
2611 | ||
84d65814 DN |
2612 | /* Helper for prepare_names_to_update. Mark the definition site for |
2613 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2614 | prepare_names_to_update. */ | |
0bca51f0 DN |
2615 | |
2616 | static void | |
95dd3097 | 2617 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2618 | { |
355fe088 | 2619 | gimple *stmt; |
0bca51f0 DN |
2620 | basic_block bb; |
2621 | ||
4ad14919 RG |
2622 | gcc_checking_assert (names_to_release == NULL |
2623 | || !bitmap_bit_p (names_to_release, | |
2624 | SSA_NAME_VERSION (name))); | |
0bca51f0 DN |
2625 | |
2626 | stmt = SSA_NAME_DEF_STMT (name); | |
726a989a | 2627 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2628 | if (bb) |
2629 | { | |
8b1c6fd7 | 2630 | gcc_checking_assert (bb->index < last_basic_block_for_fn (cfun)); |
95dd3097 ZD |
2631 | mark_block_for_update (bb); |
2632 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2633 | } |
2634 | } | |
2635 | ||
2636 | ||
84d65814 | 2637 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2638 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2639 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2640 | |
2641 | static void | |
95dd3097 | 2642 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2643 | { |
dfea6c85 | 2644 | unsigned i = 0; |
0bca51f0 | 2645 | bitmap_iterator bi; |
b6e7e9af | 2646 | sbitmap_iterator sbi; |
0bca51f0 DN |
2647 | |
2648 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2649 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2650 | defining basic block (which most likely doesn't exist). Notice | |
2651 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2652 | want to replace existing instances. */ | |
2653 | if (names_to_release) | |
2654 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
d7c028c0 | 2655 | bitmap_clear_bit (new_ssa_names, i); |
0bca51f0 | 2656 | |
84d65814 DN |
2657 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2658 | names may be considered to be live-in on blocks that contain | |
2659 | definitions for their replacements. */ | |
d4ac4ce2 | 2660 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2661 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2662 | |
0bca51f0 DN |
2663 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2664 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
d4ac4ce2 | 2665 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2666 | { |
2667 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2668 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2669 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2670 | } |
0bca51f0 DN |
2671 | } |
2672 | ||
2673 | ||
2674 | /* Dump all the names replaced by NAME to FILE. */ | |
2675 | ||
2676 | void | |
2677 | dump_names_replaced_by (FILE *file, tree name) | |
2678 | { | |
2679 | unsigned i; | |
2680 | bitmap old_set; | |
2681 | bitmap_iterator bi; | |
2682 | ||
2683 | print_generic_expr (file, name, 0); | |
2684 | fprintf (file, " -> { "); | |
2685 | ||
2686 | old_set = names_replaced_by (name); | |
2687 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2688 | { | |
2689 | print_generic_expr (file, ssa_name (i), 0); | |
2690 | fprintf (file, " "); | |
2691 | } | |
2692 | ||
2693 | fprintf (file, "}\n"); | |
2694 | } | |
2695 | ||
2696 | ||
2697 | /* Dump all the names replaced by NAME to stderr. */ | |
2698 | ||
24e47c76 | 2699 | DEBUG_FUNCTION void |
0bca51f0 DN |
2700 | debug_names_replaced_by (tree name) |
2701 | { | |
2702 | dump_names_replaced_by (stderr, name); | |
2703 | } | |
2704 | ||
2705 | ||
84d65814 | 2706 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2707 | |
2708 | void | |
84d65814 | 2709 | dump_update_ssa (FILE *file) |
0bca51f0 | 2710 | { |
dfea6c85 | 2711 | unsigned i = 0; |
0bca51f0 DN |
2712 | bitmap_iterator bi; |
2713 | ||
5006671f | 2714 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
2715 | return; |
2716 | ||
f61e445a | 2717 | if (new_ssa_names && bitmap_first_set_bit (new_ssa_names) >= 0) |
0bca51f0 | 2718 | { |
b6e7e9af KH |
2719 | sbitmap_iterator sbi; |
2720 | ||
0bca51f0 DN |
2721 | fprintf (file, "\nSSA replacement table\n"); |
2722 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2723 | "O_1, ..., O_j\n\n"); | |
2724 | ||
d4ac4ce2 | 2725 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
b6e7e9af | 2726 | dump_names_replaced_by (file, ssa_name (i)); |
0bca51f0 DN |
2727 | } |
2728 | ||
13714310 | 2729 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
0bca51f0 | 2730 | { |
427f99e2 | 2731 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
13714310 | 2732 | dump_decl_set (file, symbols_to_rename_set); |
5006671f | 2733 | fprintf (file, "\n"); |
0bca51f0 DN |
2734 | } |
2735 | ||
0bca51f0 DN |
2736 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2737 | { | |
427f99e2 | 2738 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
0bca51f0 DN |
2739 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2740 | { | |
2741 | print_generic_expr (file, ssa_name (i), 0); | |
2742 | fprintf (file, " "); | |
2743 | } | |
427f99e2 | 2744 | fprintf (file, "\n"); |
0bca51f0 | 2745 | } |
0bca51f0 DN |
2746 | } |
2747 | ||
2748 | ||
84d65814 | 2749 | /* Dump SSA update information to stderr. */ |
0bca51f0 | 2750 | |
24e47c76 | 2751 | DEBUG_FUNCTION void |
84d65814 | 2752 | debug_update_ssa (void) |
0bca51f0 | 2753 | { |
84d65814 | 2754 | dump_update_ssa (stderr); |
0bca51f0 DN |
2755 | } |
2756 | ||
2757 | ||
2758 | /* Initialize data structures used for incremental SSA updates. */ | |
2759 | ||
2760 | static void | |
5006671f | 2761 | init_update_ssa (struct function *fn) |
0bca51f0 | 2762 | { |
84d65814 | 2763 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2764 | add_new_name_mapping are typically done after creating new SSA |
2765 | names, so we'll need to reallocate these arrays. */ | |
2766 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2767 | bitmap_clear (old_ssa_names); |
0bca51f0 DN |
2768 | |
2769 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2770 | bitmap_clear (new_ssa_names); |
0bca51f0 | 2771 | |
891f2df6 RG |
2772 | bitmap_obstack_initialize (&update_ssa_obstack); |
2773 | ||
0bca51f0 | 2774 | names_to_release = NULL; |
5006671f | 2775 | update_ssa_initialized_fn = fn; |
0bca51f0 DN |
2776 | } |
2777 | ||
2778 | ||
2779 | /* Deallocate data structures used for incremental SSA updates. */ | |
2780 | ||
84d65814 | 2781 | void |
0bca51f0 DN |
2782 | delete_update_ssa (void) |
2783 | { | |
2784 | unsigned i; | |
2785 | bitmap_iterator bi; | |
2786 | ||
2787 | sbitmap_free (old_ssa_names); | |
2788 | old_ssa_names = NULL; | |
2789 | ||
2790 | sbitmap_free (new_ssa_names); | |
2791 | new_ssa_names = NULL; | |
2792 | ||
13714310 RG |
2793 | BITMAP_FREE (symbols_to_rename_set); |
2794 | symbols_to_rename_set = NULL; | |
9771b263 | 2795 | symbols_to_rename.release (); |
0bca51f0 DN |
2796 | |
2797 | if (names_to_release) | |
2798 | { | |
2799 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2800 | release_ssa_name (ssa_name (i)); | |
2801 | BITMAP_FREE (names_to_release); | |
2802 | } | |
2803 | ||
95dd3097 | 2804 | clear_ssa_name_info (); |
38635499 DN |
2805 | |
2806 | fini_ssa_renamer (); | |
2807 | ||
2808 | if (blocks_with_phis_to_rewrite) | |
2809 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2810 | { | |
538dd0b7 | 2811 | vec<gphi *> phis = phis_to_rewrite[i]; |
9771b263 DN |
2812 | phis.release (); |
2813 | phis_to_rewrite[i].create (0); | |
38635499 DN |
2814 | } |
2815 | ||
2816 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2817 | BITMAP_FREE (blocks_to_update); | |
891f2df6 | 2818 | |
5006671f | 2819 | update_ssa_initialized_fn = NULL; |
0bca51f0 DN |
2820 | } |
2821 | ||
2822 | ||
2823 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
45db3141 RG |
2824 | operand pointed to by DEF_P with the newly created name. If DEF_P |
2825 | is NULL then STMT should be a GIMPLE assignment. | |
2826 | Return the new name and register the replacement mapping <NEW, OLD> in | |
0bca51f0 DN |
2827 | update_ssa's tables. */ |
2828 | ||
2829 | tree | |
355fe088 | 2830 | create_new_def_for (tree old_name, gimple *stmt, def_operand_p def) |
0bca51f0 | 2831 | { |
45db3141 | 2832 | tree new_name; |
0bca51f0 | 2833 | |
45db3141 RG |
2834 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
2835 | ||
2836 | if (!update_ssa_initialized_fn) | |
2837 | init_update_ssa (cfun); | |
2838 | ||
2839 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2840 | ||
2841 | new_name = duplicate_ssa_name (old_name, stmt); | |
2842 | if (def) | |
2843 | SET_DEF (def, new_name); | |
2844 | else | |
2845 | gimple_assign_set_lhs (stmt, new_name); | |
0bca51f0 | 2846 | |
726a989a | 2847 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 | 2848 | { |
726a989a | 2849 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2850 | |
2851 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
31ff2426 | 2852 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
0bca51f0 DN |
2853 | } |
2854 | ||
45db3141 | 2855 | add_new_name_mapping (new_name, old_name); |
0bca51f0 DN |
2856 | |
2857 | /* For the benefit of passes that will be updating the SSA form on | |
2858 | their own, set the current reaching definition of OLD_NAME to be | |
2859 | NEW_NAME. */ | |
8812aab1 | 2860 | get_ssa_name_ann (old_name)->info.current_def = new_name; |
0bca51f0 | 2861 | |
45db3141 | 2862 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
0bca51f0 | 2863 | |
45db3141 | 2864 | return new_name; |
0bca51f0 DN |
2865 | } |
2866 | ||
2867 | ||
525174a2 | 2868 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
0bca51f0 DN |
2869 | |
2870 | void | |
525174a2 | 2871 | mark_virtual_operands_for_renaming (struct function *fn) |
0bca51f0 | 2872 | { |
525174a2 RG |
2873 | fn->gimple_df->ssa_renaming_needed = 1; |
2874 | fn->gimple_df->rename_vops = 1; | |
0bca51f0 DN |
2875 | } |
2876 | ||
3d9c733e AM |
2877 | /* Replace all uses of NAME by underlying variable and mark it |
2878 | for renaming. This assumes the defining statement of NAME is | |
2879 | going to be removed. */ | |
2880 | ||
2881 | void | |
2882 | mark_virtual_operand_for_renaming (tree name) | |
2883 | { | |
2884 | tree name_var = SSA_NAME_VAR (name); | |
2885 | bool used = false; | |
2886 | imm_use_iterator iter; | |
2887 | use_operand_p use_p; | |
355fe088 | 2888 | gimple *stmt; |
3d9c733e AM |
2889 | |
2890 | gcc_assert (VAR_DECL_IS_VIRTUAL_OPERAND (name_var)); | |
2891 | FOR_EACH_IMM_USE_STMT (stmt, iter, name) | |
2892 | { | |
2893 | FOR_EACH_IMM_USE_ON_STMT (use_p, iter) | |
2894 | SET_USE (use_p, name_var); | |
2895 | used = true; | |
2896 | } | |
2897 | if (used) | |
2898 | mark_virtual_operands_for_renaming (cfun); | |
2899 | } | |
2900 | ||
2901 | /* Replace all uses of the virtual PHI result by its underlying variable | |
2902 | and mark it for renaming. This assumes the PHI node is going to be | |
2903 | removed. */ | |
2904 | ||
2905 | void | |
538dd0b7 | 2906 | mark_virtual_phi_result_for_renaming (gphi *phi) |
3d9c733e AM |
2907 | { |
2908 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2909 | { | |
2910 | fprintf (dump_file, "Marking result for renaming : "); | |
2911 | print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
2912 | fprintf (dump_file, "\n"); | |
2913 | } | |
2914 | ||
2915 | mark_virtual_operand_for_renaming (gimple_phi_result (phi)); | |
2916 | } | |
0bca51f0 | 2917 | |
5006671f RG |
2918 | /* Return true if there is any work to be done by update_ssa |
2919 | for function FN. */ | |
0bca51f0 DN |
2920 | |
2921 | bool | |
5006671f | 2922 | need_ssa_update_p (struct function *fn) |
0bca51f0 | 2923 | { |
5006671f RG |
2924 | gcc_assert (fn != NULL); |
2925 | return (update_ssa_initialized_fn == fn | |
13714310 | 2926 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
0bca51f0 DN |
2927 | } |
2928 | ||
0bca51f0 DN |
2929 | /* Return true if name N has been registered in the replacement table. */ |
2930 | ||
2931 | bool | |
726a989a | 2932 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 | 2933 | { |
5006671f | 2934 | if (!update_ssa_initialized_fn) |
0bca51f0 DN |
2935 | return false; |
2936 | ||
5006671f RG |
2937 | gcc_assert (update_ssa_initialized_fn == cfun); |
2938 | ||
2939 | return is_new_name (n) || is_old_name (n); | |
0bca51f0 DN |
2940 | } |
2941 | ||
2942 | ||
0bca51f0 DN |
2943 | /* Mark NAME to be released after update_ssa has finished. */ |
2944 | ||
2945 | void | |
2946 | release_ssa_name_after_update_ssa (tree name) | |
2947 | { | |
5006671f | 2948 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
0bca51f0 DN |
2949 | |
2950 | if (names_to_release == NULL) | |
2951 | names_to_release = BITMAP_ALLOC (NULL); | |
2952 | ||
2953 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2954 | } | |
2955 | ||
2956 | ||
2957 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2958 | frontier information. BLOCKS is the set of blocks to be updated. | |
2959 | ||
2960 | This is slightly different than the regular PHI insertion | |
2961 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2962 | real names (i.e., GIMPLE registers) are inserted: | |
b8698a0f | 2963 | |
0bca51f0 DN |
2964 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
2965 | nodes inside the region affected by the block that defines VAR | |
2966 | and the blocks that define all its replacements. All these | |
84d65814 | 2967 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
2968 | |
2969 | First, we compute the entry point to the region (ENTRY). This is | |
2970 | given by the nearest common dominator to all the definition | |
2971 | blocks. When computing the iterated dominance frontier (IDF), any | |
2972 | block not strictly dominated by ENTRY is ignored. | |
2973 | ||
2974 | We then call the standard PHI insertion algorithm with the pruned | |
2975 | IDF. | |
2976 | ||
2977 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
2978 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
2979 | ||
2980 | static void | |
0fc555fb | 2981 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
0bca51f0 DN |
2982 | unsigned update_flags) |
2983 | { | |
2984 | basic_block entry; | |
526ceb68 | 2985 | def_blocks *db; |
0bca51f0 DN |
2986 | bitmap idf, pruned_idf; |
2987 | bitmap_iterator bi; | |
2988 | unsigned i; | |
2989 | ||
0bca51f0 | 2990 | if (TREE_CODE (var) == SSA_NAME) |
77a74ed7 | 2991 | gcc_checking_assert (is_old_name (var)); |
0bca51f0 | 2992 | else |
13714310 | 2993 | gcc_checking_assert (marked_for_renaming (var)); |
0bca51f0 DN |
2994 | |
2995 | /* Get all the definition sites for VAR. */ | |
2996 | db = find_def_blocks_for (var); | |
2997 | ||
2998 | /* No need to do anything if there were no definitions to VAR. */ | |
2999 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3000 | return; | |
3001 | ||
3002 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 3003 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
3004 | pruned_idf = BITMAP_ALLOC (NULL); |
3005 | ||
3006 | if (TREE_CODE (var) == SSA_NAME) | |
3007 | { | |
3008 | if (update_flags == TODO_update_ssa) | |
3009 | { | |
3010 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3011 | only interested in IDF blocks dominated by the nearest | |
3012 | common dominator of all the definition blocks. */ | |
3013 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3014 | db->def_blocks); | |
fefa31b5 | 3015 | if (entry != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
0bca51f0 | 3016 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) |
06e28de2 DM |
3017 | if (BASIC_BLOCK_FOR_FN (cfun, i) != entry |
3018 | && dominated_by_p (CDI_DOMINATORS, | |
3019 | BASIC_BLOCK_FOR_FN (cfun, i), entry)) | |
0bca51f0 DN |
3020 | bitmap_set_bit (pruned_idf, i); |
3021 | } | |
3022 | else | |
3023 | { | |
3024 | /* Otherwise, do not prune the IDF for VAR. */ | |
4ad14919 | 3025 | gcc_checking_assert (update_flags == TODO_update_ssa_full_phi); |
0bca51f0 DN |
3026 | bitmap_copy (pruned_idf, idf); |
3027 | } | |
3028 | } | |
3029 | else | |
3030 | { | |
3031 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3032 | for the first time, so we need to compute the full IDF for | |
3033 | it. */ | |
3034 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
3035 | } |
3036 | ||
3037 | if (!bitmap_empty_p (pruned_idf)) | |
3038 | { | |
3039 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3040 | are included in the region to be updated. The feeding blocks | |
3041 | are important to guarantee that the PHI arguments are renamed | |
3042 | properly. */ | |
38635499 DN |
3043 | |
3044 | /* FIXME, this is not needed if we are updating symbols. We are | |
3045 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
3046 | bitmap_ior_into (blocks, pruned_idf); |
3047 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3048 | { | |
3049 | edge e; | |
3050 | edge_iterator ei; | |
06e28de2 | 3051 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); |
0bca51f0 DN |
3052 | |
3053 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3054 | if (e->src->index >= 0) | |
3055 | bitmap_set_bit (blocks, e->src->index); | |
3056 | } | |
3057 | ||
3058 | insert_phi_nodes_for (var, pruned_idf, true); | |
3059 | } | |
3060 | ||
3061 | BITMAP_FREE (pruned_idf); | |
3062 | BITMAP_FREE (idf); | |
3063 | } | |
3064 | ||
fa5556de RB |
3065 | /* Sort symbols_to_rename after their DECL_UID. */ |
3066 | ||
3067 | static int | |
3068 | insert_updated_phi_nodes_compare_uids (const void *a, const void *b) | |
3069 | { | |
3070 | const_tree syma = *(const const_tree *)a; | |
3071 | const_tree symb = *(const const_tree *)b; | |
3072 | if (DECL_UID (syma) == DECL_UID (symb)) | |
3073 | return 0; | |
3074 | return DECL_UID (syma) < DECL_UID (symb) ? -1 : 1; | |
3075 | } | |
0bca51f0 DN |
3076 | |
3077 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3078 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3079 | ||
3080 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3081 | NEW_SSA_NAMES are all re-written to be reached by the | |
3082 | appropriate definition from NEW_SSA_NAMES. | |
3083 | ||
3084 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3085 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3086 | ||
3087 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
45db3141 | 3088 | calling create_new_def_for to create new defs for names that the |
0bca51f0 DN |
3089 | caller wants to replace. |
3090 | ||
45db3141 RG |
3091 | The caller cretaes the new names to be inserted and the names that need |
3092 | to be replaced by calling create_new_def_for for each old definition | |
3093 | to be replaced. Note that the function assumes that the | |
3094 | new defining statement has already been inserted in the IL. | |
0bca51f0 DN |
3095 | |
3096 | For instance, given the following code: | |
3097 | ||
3098 | 1 L0: | |
3099 | 2 x_1 = PHI (0, x_5) | |
3100 | 3 if (x_1 < 10) | |
3101 | 4 if (x_1 > 7) | |
3102 | 5 y_2 = 0 | |
3103 | 6 else | |
3104 | 7 y_3 = x_1 + x_7 | |
3105 | 8 endif | |
3106 | 9 x_5 = x_1 + 1 | |
3107 | 10 goto L0; | |
3108 | 11 endif | |
3109 | ||
3110 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3111 | ||
3112 | 1 L0: | |
3113 | 2 x_1 = PHI (0, x_5) | |
3114 | 3 if (x_1 < 10) | |
3115 | 4 x_10 = ... | |
3116 | 5 if (x_1 > 7) | |
3117 | 6 y_2 = 0 | |
3118 | 7 else | |
3119 | 8 x_11 = ... | |
3120 | 9 y_3 = x_1 + x_7 | |
3121 | 10 endif | |
3122 | 11 x_5 = x_1 + 1 | |
3123 | 12 goto L0; | |
3124 | 13 endif | |
3125 | ||
3126 | We want to replace all the uses of x_1 with the new definitions of | |
3127 | x_10 and x_11. Note that the only uses that should be replaced are | |
3128 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3129 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3130 | renaming). | |
3131 | ||
3132 | Additionally, we may need to insert a PHI node at line 11 because | |
3133 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3134 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3135 | nodes is optional. They are not strictly necessary to preserve the | |
3136 | SSA form, and depending on what the caller inserted, they may not | |
3137 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3138 | aspects of how update_ssa operates, see the documentation for | |
3139 | TODO_update_ssa*. */ | |
3140 | ||
3141 | void | |
3142 | update_ssa (unsigned update_flags) | |
3143 | { | |
0bca51f0 DN |
3144 | basic_block bb, start_bb; |
3145 | bitmap_iterator bi; | |
dfea6c85 | 3146 | unsigned i = 0; |
0bca51f0 | 3147 | bool insert_phi_p; |
b6e7e9af | 3148 | sbitmap_iterator sbi; |
13714310 | 3149 | tree sym; |
0bca51f0 | 3150 | |
580b2c2e SB |
3151 | /* Only one update flag should be set. */ |
3152 | gcc_assert (update_flags == TODO_update_ssa | |
3153 | || update_flags == TODO_update_ssa_no_phi | |
3154 | || update_flags == TODO_update_ssa_full_phi | |
3155 | || update_flags == TODO_update_ssa_only_virtuals); | |
3156 | ||
5006671f | 3157 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
3158 | return; |
3159 | ||
b2b29377 MM |
3160 | if (flag_checking) |
3161 | { | |
3162 | timevar_push (TV_TREE_STMT_VERIFY); | |
90ad8d00 | 3163 | |
b2b29377 | 3164 | bool err = false; |
90ad8d00 | 3165 | |
b2b29377 | 3166 | FOR_EACH_BB_FN (bb, cfun) |
90ad8d00 | 3167 | { |
b2b29377 MM |
3168 | gimple_stmt_iterator gsi; |
3169 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
90ad8d00 | 3170 | { |
b2b29377 | 3171 | gimple *stmt = gsi_stmt (gsi); |
90ad8d00 | 3172 | |
b2b29377 MM |
3173 | ssa_op_iter i; |
3174 | use_operand_p use_p; | |
3175 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) | |
90ad8d00 | 3176 | { |
b2b29377 MM |
3177 | tree use = USE_FROM_PTR (use_p); |
3178 | if (TREE_CODE (use) != SSA_NAME) | |
3179 | continue; | |
3180 | ||
3181 | if (SSA_NAME_IN_FREE_LIST (use)) | |
3182 | { | |
3183 | error ("statement uses released SSA name:"); | |
3184 | debug_gimple_stmt (stmt); | |
3185 | fprintf (stderr, "The use of "); | |
3186 | print_generic_expr (stderr, use, 0); | |
3187 | fprintf (stderr," should have been replaced\n"); | |
3188 | err = true; | |
3189 | } | |
90ad8d00 TV |
3190 | } |
3191 | } | |
3192 | } | |
90ad8d00 | 3193 | |
b2b29377 MM |
3194 | if (err) |
3195 | internal_error ("cannot update SSA form"); | |
90ad8d00 | 3196 | |
b2b29377 MM |
3197 | timevar_pop (TV_TREE_STMT_VERIFY); |
3198 | } | |
90ad8d00 | 3199 | |
0bca51f0 DN |
3200 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
3201 | ||
427f99e2 MJ |
3202 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3203 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3204 | ||
5006671f RG |
3205 | if (!update_ssa_initialized_fn) |
3206 | init_update_ssa (cfun); | |
580b2c2e SB |
3207 | else if (update_flags == TODO_update_ssa_only_virtuals) |
3208 | { | |
3209 | /* If we only need to update virtuals, remove all the mappings for | |
3210 | real names before proceeding. The caller is responsible for | |
3211 | having dealt with the name mappings before calling update_ssa. */ | |
f61e445a LC |
3212 | bitmap_clear (old_ssa_names); |
3213 | bitmap_clear (new_ssa_names); | |
580b2c2e SB |
3214 | } |
3215 | ||
5006671f RG |
3216 | gcc_assert (update_ssa_initialized_fn == cfun); |
3217 | ||
2ce79879 | 3218 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
9771b263 | 3219 | if (!phis_to_rewrite.exists ()) |
8b1c6fd7 | 3220 | phis_to_rewrite.create (last_basic_block_for_fn (cfun) + 1); |
95dd3097 | 3221 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3222 | |
0bca51f0 DN |
3223 | /* Ensure that the dominance information is up-to-date. */ |
3224 | calculate_dominance_info (CDI_DOMINATORS); | |
3225 | ||
84d65814 | 3226 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 | 3227 | |
84d65814 DN |
3228 | /* If there are names defined in the replacement table, prepare |
3229 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3230 | OLD_SSA_NAMES. */ | |
f61e445a | 3231 | if (bitmap_first_set_bit (new_ssa_names) >= 0) |
84d65814 | 3232 | { |
95dd3097 | 3233 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3234 | |
3235 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3236 | removal, and there are no symbols to rename, then there's | |
3237 | nothing else to do. */ | |
f61e445a | 3238 | if (bitmap_first_set_bit (new_ssa_names) < 0 |
13714310 | 3239 | && !cfun->gimple_df->ssa_renaming_needed) |
84d65814 DN |
3240 | goto done; |
3241 | } | |
3242 | ||
3243 | /* Next, determine the block at which to start the renaming process. */ | |
13714310 | 3244 | if (cfun->gimple_df->ssa_renaming_needed) |
84d65814 | 3245 | { |
b4e209fd RG |
3246 | /* If we rename bare symbols initialize the mapping to |
3247 | auxiliar info we need to keep track of. */ | |
c203e8a7 | 3248 | var_infos = new hash_table<var_info_hasher> (47); |
b4e209fd | 3249 | |
84d65814 DN |
3250 | /* If we have to rename some symbols from scratch, we need to |
3251 | start the process at the root of the CFG. FIXME, it should | |
3252 | be possible to determine the nearest block that had a | |
3253 | definition for each of the symbols that are marked for | |
3254 | updating. For now this seems more work than it's worth. */ | |
fefa31b5 | 3255 | start_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
84d65814 | 3256 | |
38635499 | 3257 | /* Traverse the CFG looking for existing definitions and uses of |
13714310 | 3258 | symbols in SSA operands. Mark interesting blocks and |
38635499 DN |
3259 | statements and set local live-in information for the PHI |
3260 | placement heuristics. */ | |
95dd3097 | 3261 | prepare_block_for_update (start_bb, insert_phi_p); |
343c5d46 | 3262 | |
b2b29377 MM |
3263 | if (flag_checking) |
3264 | for (i = 1; i < num_ssa_names; ++i) | |
3265 | { | |
3266 | tree name = ssa_name (i); | |
3267 | if (!name | |
3268 | || virtual_operand_p (name)) | |
3269 | continue; | |
3270 | ||
3271 | /* For all but virtual operands, which do not have SSA names | |
3272 | with overlapping life ranges, ensure that symbols marked | |
3273 | for renaming do not have existing SSA names associated with | |
3274 | them as we do not re-write them out-of-SSA before going | |
3275 | into SSA for the remaining symbol uses. */ | |
3276 | if (marked_for_renaming (SSA_NAME_VAR (name))) | |
3277 | { | |
3278 | fprintf (stderr, "Existing SSA name for symbol marked for " | |
3279 | "renaming: "); | |
3280 | print_generic_expr (stderr, name, TDF_SLIM); | |
3281 | fprintf (stderr, "\n"); | |
3282 | internal_error ("SSA corruption"); | |
3283 | } | |
3284 | } | |
0bca51f0 DN |
3285 | } |
3286 | else | |
84d65814 DN |
3287 | { |
3288 | /* Otherwise, the entry block to the region is the nearest | |
3289 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3290 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3291 | blocks_to_update); | |
84d65814 | 3292 | } |
0bca51f0 DN |
3293 | |
3294 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3295 | of every block, creating new definitions for names in OLD_SSA_NAMES |
13714310 | 3296 | and for symbols found. */ |
0bca51f0 DN |
3297 | if (insert_phi_p) |
3298 | { | |
0fc555fb | 3299 | bitmap_head *dfs; |
9caf90a8 KH |
3300 | |
3301 | /* If the caller requested PHI nodes to be added, compute | |
3302 | dominance frontiers. */ | |
8b1c6fd7 | 3303 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
11cd3bed | 3304 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3305 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
9caf90a8 KH |
3306 | compute_dominance_frontiers (dfs); |
3307 | ||
f61e445a | 3308 | if (bitmap_first_set_bit (old_ssa_names) >= 0) |
0bca51f0 | 3309 | { |
b6e7e9af KH |
3310 | sbitmap_iterator sbi; |
3311 | ||
84d65814 DN |
3312 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3313 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3314 | will grow while we are traversing it (but it will not | |
3315 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3316 | for traversal. */ | |
5829cc0f | 3317 | sbitmap tmp = sbitmap_alloc (SBITMAP_SIZE (old_ssa_names)); |
f61e445a | 3318 | bitmap_copy (tmp, old_ssa_names); |
d4ac4ce2 | 3319 | EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi) |
95dd3097 | 3320 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3321 | update_flags); |
0bca51f0 DN |
3322 | sbitmap_free (tmp); |
3323 | } | |
3324 | ||
fa5556de | 3325 | symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids); |
9771b263 | 3326 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
13714310 | 3327 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, |
38635499 | 3328 | update_flags); |
0bca51f0 | 3329 | |
11cd3bed | 3330 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3331 | bitmap_clear (&dfs[bb->index]); |
9caf90a8 KH |
3332 | free (dfs); |
3333 | ||
0bca51f0 DN |
3334 | /* Insertion of PHI nodes may have added blocks to the region. |
3335 | We need to re-compute START_BB to include the newly added | |
3336 | blocks. */ | |
fefa31b5 | 3337 | if (start_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
95dd3097 ZD |
3338 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3339 | blocks_to_update); | |
0bca51f0 DN |
3340 | } |
3341 | ||
3342 | /* Reset the current definition for name and symbol before renaming | |
3343 | the sub-graph. */ | |
d4ac4ce2 | 3344 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
8812aab1 | 3345 | get_ssa_name_ann (ssa_name (i))->info.current_def = NULL_TREE; |
0bca51f0 | 3346 | |
9771b263 | 3347 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
8812aab1 | 3348 | get_var_info (sym)->info.current_def = NULL_TREE; |
0bca51f0 DN |
3349 | |
3350 | /* Now start the renaming process at START_BB. */ | |
8b1c6fd7 | 3351 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
f61e445a | 3352 | bitmap_clear (interesting_blocks); |
95dd3097 | 3353 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
d7c028c0 | 3354 | bitmap_set_bit (interesting_blocks, i); |
0bca51f0 | 3355 | |
ccf5c864 | 3356 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
0bca51f0 | 3357 | |
ccf5c864 | 3358 | sbitmap_free (interesting_blocks); |
0bca51f0 DN |
3359 | |
3360 | /* Debugging dumps. */ | |
3361 | if (dump_file) | |
3362 | { | |
3363 | int c; | |
3364 | unsigned i; | |
3365 | ||
84d65814 | 3366 | dump_update_ssa (dump_file); |
0bca51f0 | 3367 | |
427f99e2 | 3368 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
0bca51f0 DN |
3369 | start_bb->index); |
3370 | ||
3371 | c = 0; | |
95dd3097 | 3372 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 | 3373 | c++; |
8b1c6fd7 DM |
3374 | fprintf (dump_file, "Number of blocks in CFG: %d\n", |
3375 | last_basic_block_for_fn (cfun)); | |
427f99e2 | 3376 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
8b1c6fd7 | 3377 | c, PERCENT (c, last_basic_block_for_fn (cfun))); |
0bca51f0 DN |
3378 | |
3379 | if (dump_flags & TDF_DETAILS) | |
3380 | { | |
0eb09f31 | 3381 | fprintf (dump_file, "Affected blocks:"); |
95dd3097 | 3382 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0eb09f31 | 3383 | fprintf (dump_file, " %u", i); |
0bca51f0 DN |
3384 | fprintf (dump_file, "\n"); |
3385 | } | |
3386 | ||
3387 | fprintf (dump_file, "\n\n"); | |
3388 | } | |
3389 | ||
3390 | /* Free allocated memory. */ | |
84d65814 | 3391 | done: |
0bca51f0 DN |
3392 | delete_update_ssa (); |
3393 | ||
3394 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3395 | } |