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Commit | Line | Data |
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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" | |
24 | #include "tm.h" | |
40e23961 MC |
25 | #include "alias.h" |
26 | #include "symtab.h" | |
6de9cd9a | 27 | #include "tree.h" |
40e23961 | 28 | #include "fold-const.h" |
6de9cd9a | 29 | #include "flags.h" |
6de9cd9a DN |
30 | #include "tm_p.h" |
31 | #include "langhooks.h" | |
60393bbc | 32 | #include "predict.h" |
83685514 | 33 | #include "hard-reg-set.h" |
6de9cd9a | 34 | #include "function.h" |
60393bbc AM |
35 | #include "dominance.h" |
36 | #include "cfg.h" | |
37 | #include "cfganal.h" | |
38 | #include "basic-block.h" | |
cf835838 | 39 | #include "gimple-pretty-print.h" |
2fb9a547 AM |
40 | #include "tree-ssa-alias.h" |
41 | #include "internal-fn.h" | |
42 | #include "gimple-expr.h" | |
726a989a | 43 | #include "gimple.h" |
5be5c238 | 44 | #include "gimple-iterator.h" |
442b4905 AM |
45 | #include "gimple-ssa.h" |
46 | #include "tree-cfg.h" | |
47 | #include "tree-phinodes.h" | |
48 | #include "ssa-iterators.h" | |
d8a2d370 | 49 | #include "stringpool.h" |
442b4905 AM |
50 | #include "tree-ssanames.h" |
51 | #include "tree-into-ssa.h" | |
36566b39 | 52 | #include "rtl.h" |
36566b39 PK |
53 | #include "insn-config.h" |
54 | #include "expmed.h" | |
55 | #include "dojump.h" | |
56 | #include "explow.h" | |
57 | #include "calls.h" | |
58 | #include "emit-rtl.h" | |
59 | #include "varasm.h" | |
60 | #include "stmt.h" | |
d8a2d370 | 61 | #include "expr.h" |
442b4905 AM |
62 | #include "tree-dfa.h" |
63 | #include "tree-ssa.h" | |
6de9cd9a | 64 | #include "tree-inline.h" |
6de9cd9a DN |
65 | #include "tree-pass.h" |
66 | #include "cfgloop.h" | |
67 | #include "domwalk.h" | |
84d65814 | 68 | #include "params.h" |
d8d707b4 | 69 | #include "diagnostic-core.h" |
6de9cd9a | 70 | |
1fe37220 | 71 | #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y)) |
726a989a | 72 | |
6de9cd9a DN |
73 | /* This file builds the SSA form for a function as described in: |
74 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
75 | Computing Static Single Assignment Form and the Control Dependence | |
76 | Graph. ACM Transactions on Programming Languages and Systems, | |
77 | 13(4):451-490, October 1991. */ | |
78 | ||
6de9cd9a DN |
79 | /* Structure to map a variable VAR to the set of blocks that contain |
80 | definitions for VAR. */ | |
81 | struct def_blocks_d | |
82 | { | |
6de9cd9a DN |
83 | /* Blocks that contain definitions of VAR. Bit I will be set if the |
84 | Ith block contains a definition of VAR. */ | |
85 | bitmap def_blocks; | |
86 | ||
7256233c | 87 | /* Blocks that contain a PHI node for VAR. */ |
5f240ec4 ZD |
88 | bitmap phi_blocks; |
89 | ||
6de9cd9a DN |
90 | /* Blocks where VAR is live-on-entry. Similar semantics as |
91 | DEF_BLOCKS. */ | |
92 | bitmap livein_blocks; | |
93 | }; | |
94 | ||
d9ed2fbd RG |
95 | typedef struct def_blocks_d *def_blocks_p; |
96 | ||
6de9cd9a | 97 | |
9fae925b | 98 | /* Stack of trees used to restore the global currdefs to its original |
0bca51f0 DN |
99 | state after completing rewriting of a block and its dominator |
100 | children. Its elements have the following properties: | |
9fae925b | 101 | |
38635499 DN |
102 | - An SSA_NAME (N) indicates that the current definition of the |
103 | underlying variable should be set to the given SSA_NAME. If the | |
104 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
105 | next slot in the stack must be a _DECL node (SYM). In this case, | |
106 | the name N in the previous slot is the current reaching | |
107 | definition for SYM. | |
9fae925b | 108 | |
0bca51f0 DN |
109 | - A _DECL node indicates that the underlying variable has no |
110 | current definition. | |
7256233c | 111 | |
38635499 | 112 | - A NULL node at the top entry is used to mark the last slot |
0bca51f0 | 113 | associated with the current block. */ |
9771b263 | 114 | static vec<tree> block_defs_stack; |
3a2e4b46 | 115 | |
726a989a | 116 | |
0bca51f0 DN |
117 | /* Set of existing SSA names being replaced by update_ssa. */ |
118 | static sbitmap old_ssa_names; | |
119 | ||
120 | /* Set of new SSA names being added by update_ssa. Note that both | |
121 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
122 | the operations done on them are presence tests. */ | |
123 | static sbitmap new_ssa_names; | |
124 | ||
16876bdc | 125 | static sbitmap interesting_blocks; |
726a989a | 126 | |
0bca51f0 DN |
127 | /* Set of SSA names that have been marked to be released after they |
128 | were registered in the replacement table. They will be finally | |
129 | released after we finish updating the SSA web. */ | |
130 | static bitmap names_to_release; | |
131 | ||
9771b263 | 132 | /* vec of vec of PHIs to rewrite in a basic block. Element I corresponds |
580b2c2e SB |
133 | the to basic block with index I. Allocated once per compilation, *not* |
134 | released between different functions. */ | |
538dd0b7 | 135 | static vec< vec<gphi *> > phis_to_rewrite; |
2ce79879 ZD |
136 | |
137 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
138 | static bitmap blocks_with_phis_to_rewrite; |
139 | ||
0bca51f0 | 140 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
45db3141 RG |
141 | to grow as the callers to create_new_def_for will create new names on |
142 | the fly. | |
143 | FIXME. Currently set to 1/3 to avoid frequent reallocations but still | |
144 | need to find a reasonable growth strategy. */ | |
0bca51f0 DN |
145 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) |
146 | ||
0bca51f0 | 147 | |
5006671f | 148 | /* The function the SSA updating data structures have been initialized for. |
45db3141 | 149 | NULL if they need to be initialized by create_new_def_for. */ |
5006671f | 150 | static struct function *update_ssa_initialized_fn = NULL; |
0bca51f0 | 151 | |
6de9cd9a DN |
152 | /* Global data to attach to the main dominator walk structure. */ |
153 | struct mark_def_sites_global_data | |
154 | { | |
0bca51f0 DN |
155 | /* This bitmap contains the variables which are set before they |
156 | are used in a basic block. */ | |
7d793e36 | 157 | bitmap kills; |
6de9cd9a DN |
158 | }; |
159 | ||
80560f95 AM |
160 | /* It is advantageous to avoid things like life analysis for variables which |
161 | do not need PHI nodes. This enum describes whether or not a particular | |
162 | variable may need a PHI node. */ | |
163 | ||
164 | enum need_phi_state { | |
165 | /* This is the default. If we are still in this state after finding | |
166 | all the definition and use sites, then we will assume the variable | |
167 | needs PHI nodes. This is probably an overly conservative assumption. */ | |
168 | NEED_PHI_STATE_UNKNOWN, | |
169 | ||
170 | /* This state indicates that we have seen one or more sets of the | |
171 | variable in a single basic block and that the sets dominate all | |
172 | uses seen so far. If after finding all definition and use sites | |
173 | we are still in this state, then the variable does not need any | |
174 | PHI nodes. */ | |
175 | NEED_PHI_STATE_NO, | |
176 | ||
177 | /* This state indicates that we have either seen multiple definitions of | |
178 | the variable in multiple blocks, or that we encountered a use in a | |
179 | block that was not dominated by the block containing the set(s) of | |
180 | this variable. This variable is assumed to need PHI nodes. */ | |
181 | NEED_PHI_STATE_MAYBE | |
182 | }; | |
183 | ||
8812aab1 RG |
184 | /* Information stored for both SSA names and decls. */ |
185 | struct common_info_d | |
b4e209fd | 186 | { |
b4e209fd RG |
187 | /* This field indicates whether or not the variable may need PHI nodes. |
188 | See the enum's definition for more detailed information about the | |
189 | states. */ | |
190 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
191 | ||
8812aab1 | 192 | /* The current reaching definition replacing this var. */ |
b4e209fd RG |
193 | tree current_def; |
194 | ||
8812aab1 | 195 | /* Definitions for this var. */ |
b4e209fd RG |
196 | struct def_blocks_d def_blocks; |
197 | }; | |
198 | ||
8812aab1 RG |
199 | /* The information associated with decls and SSA names. */ |
200 | typedef struct common_info_d *common_info_p; | |
201 | ||
202 | /* Information stored for decls. */ | |
203 | struct var_info_d | |
204 | { | |
205 | /* The variable. */ | |
206 | tree var; | |
207 | ||
208 | /* Information stored for both SSA names and decls. */ | |
209 | struct common_info_d info; | |
210 | }; | |
211 | ||
b4e209fd RG |
212 | /* The information associated with decls. */ |
213 | typedef struct var_info_d *var_info_p; | |
214 | ||
b4e209fd | 215 | |
bf190e8d LC |
216 | /* VAR_INFOS hashtable helpers. */ |
217 | ||
95fbe13e | 218 | struct var_info_hasher : free_ptr_hash <var_info_d> |
bf190e8d | 219 | { |
84baa4b9 TS |
220 | static inline hashval_t hash (const value_type &); |
221 | static inline bool equal (const value_type &, const compare_type &); | |
bf190e8d LC |
222 | }; |
223 | ||
224 | inline hashval_t | |
84baa4b9 | 225 | var_info_hasher::hash (const value_type &p) |
bf190e8d LC |
226 | { |
227 | return DECL_UID (p->var); | |
228 | } | |
229 | ||
230 | inline bool | |
84baa4b9 | 231 | var_info_hasher::equal (const value_type &p1, const compare_type &p2) |
bf190e8d LC |
232 | { |
233 | return p1->var == p2->var; | |
234 | } | |
235 | ||
236 | ||
b4e209fd RG |
237 | /* Each entry in VAR_INFOS contains an element of type STRUCT |
238 | VAR_INFO_D. */ | |
c203e8a7 | 239 | static hash_table<var_info_hasher> *var_infos; |
b4e209fd RG |
240 | |
241 | ||
0bca51f0 | 242 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
243 | struct ssa_name_info |
244 | { | |
891f2df6 RG |
245 | /* Age of this record (so that info_for_ssa_name table can be cleared |
246 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
247 | are assumed to be null. */ | |
248 | unsigned age; | |
95dd3097 | 249 | |
891f2df6 RG |
250 | /* Replacement mappings, allocated from update_ssa_obstack. */ |
251 | bitmap repl_set; | |
b4e209fd | 252 | |
8812aab1 RG |
253 | /* Information stored for both SSA names and decls. */ |
254 | struct common_info_d info; | |
5f240ec4 | 255 | }; |
6de9cd9a | 256 | |
95dd3097 ZD |
257 | /* The information associated with names. */ |
258 | typedef struct ssa_name_info *ssa_name_info_p; | |
95dd3097 | 259 | |
9771b263 | 260 | static vec<ssa_name_info_p> info_for_ssa_name; |
95dd3097 ZD |
261 | static unsigned current_info_for_ssa_name_age; |
262 | ||
891f2df6 RG |
263 | static bitmap_obstack update_ssa_obstack; |
264 | ||
95dd3097 | 265 | /* The set of blocks affected by update_ssa. */ |
95dd3097 | 266 | static bitmap blocks_to_update; |
6de9cd9a | 267 | |
0bca51f0 DN |
268 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
269 | called several times to do different, but related, tasks. | |
270 | Initially, we need it to rename the whole program into SSA form. | |
271 | At other times, we may need it to only rename into SSA newly | |
272 | exposed symbols. Finally, we can also call it to incrementally fix | |
273 | an already built SSA web. */ | |
274 | enum rewrite_mode { | |
275 | /* Convert the whole function into SSA form. */ | |
276 | REWRITE_ALL, | |
277 | ||
278 | /* Incrementally update the SSA web by replacing existing SSA | |
279 | names with new ones. See update_ssa for details. */ | |
280 | REWRITE_UPDATE | |
281 | }; | |
282 | ||
13714310 RG |
283 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ |
284 | static bitmap symbols_to_rename_set; | |
9771b263 | 285 | static vec<tree> symbols_to_rename; |
13714310 RG |
286 | |
287 | /* Mark SYM for renaming. */ | |
288 | ||
289 | static void | |
290 | mark_for_renaming (tree sym) | |
291 | { | |
292 | if (!symbols_to_rename_set) | |
293 | symbols_to_rename_set = BITMAP_ALLOC (NULL); | |
294 | if (bitmap_set_bit (symbols_to_rename_set, DECL_UID (sym))) | |
9771b263 | 295 | symbols_to_rename.safe_push (sym); |
13714310 RG |
296 | } |
297 | ||
298 | /* Return true if SYM is marked for renaming. */ | |
299 | ||
300 | static bool | |
301 | marked_for_renaming (tree sym) | |
302 | { | |
70b5e7dc | 303 | if (!symbols_to_rename_set || sym == NULL_TREE) |
13714310 RG |
304 | return false; |
305 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
306 | } | |
307 | ||
308 | ||
726a989a RB |
309 | /* Return true if STMT needs to be rewritten. When renaming a subset |
310 | of the variables, not all statements will be processed. This is | |
311 | decided in mark_def_sites. */ | |
312 | ||
313 | static inline bool | |
314 | rewrite_uses_p (gimple stmt) | |
315 | { | |
316 | return gimple_visited_p (stmt); | |
317 | } | |
318 | ||
319 | ||
320 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
321 | ||
322 | static inline void | |
323 | set_rewrite_uses (gimple stmt, bool rewrite_p) | |
324 | { | |
325 | gimple_set_visited (stmt, rewrite_p); | |
326 | } | |
327 | ||
328 | ||
329 | /* Return true if the DEFs created by statement STMT should be | |
330 | registered when marking new definition sites. This is slightly | |
331 | different than rewrite_uses_p: it's used by update_ssa to | |
332 | distinguish statements that need to have both uses and defs | |
333 | processed from those that only need to have their defs processed. | |
334 | Statements that define new SSA names only need to have their defs | |
335 | registered, but they don't need to have their uses renamed. */ | |
336 | ||
337 | static inline bool | |
338 | register_defs_p (gimple stmt) | |
339 | { | |
340 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
341 | } | |
342 | ||
343 | ||
344 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
345 | ||
346 | static inline void | |
347 | set_register_defs (gimple stmt, bool register_defs_p) | |
348 | { | |
349 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
350 | } | |
351 | ||
352 | ||
5f240ec4 ZD |
353 | /* Get the information associated with NAME. */ |
354 | ||
38635499 | 355 | static inline ssa_name_info_p |
5f240ec4 ZD |
356 | get_ssa_name_ann (tree name) |
357 | { | |
95dd3097 | 358 | unsigned ver = SSA_NAME_VERSION (name); |
9771b263 | 359 | unsigned len = info_for_ssa_name.length (); |
95dd3097 ZD |
360 | struct ssa_name_info *info; |
361 | ||
f5843d08 | 362 | /* Re-allocate the vector at most once per update/into-SSA. */ |
95dd3097 | 363 | if (ver >= len) |
9771b263 | 364 | info_for_ssa_name.safe_grow_cleared (num_ssa_names); |
f5843d08 RG |
365 | |
366 | /* But allocate infos lazily. */ | |
9771b263 | 367 | info = info_for_ssa_name[ver]; |
f5843d08 | 368 | if (!info) |
95dd3097 | 369 | { |
f5843d08 RG |
370 | info = XCNEW (struct ssa_name_info); |
371 | info->age = current_info_for_ssa_name_age; | |
372 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
9771b263 | 373 | info_for_ssa_name[ver] = info; |
95dd3097 ZD |
374 | } |
375 | ||
95dd3097 ZD |
376 | if (info->age < current_info_for_ssa_name_age) |
377 | { | |
95dd3097 | 378 | info->age = current_info_for_ssa_name_age; |
8812aab1 RG |
379 | info->repl_set = NULL; |
380 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
381 | info->info.current_def = NULL_TREE; | |
382 | info->info.def_blocks.def_blocks = NULL; | |
383 | info->info.def_blocks.phi_blocks = NULL; | |
384 | info->info.def_blocks.livein_blocks = NULL; | |
95dd3097 | 385 | } |
5f240ec4 | 386 | |
95dd3097 | 387 | return info; |
5f240ec4 ZD |
388 | } |
389 | ||
b4e209fd RG |
390 | /* Return and allocate the auxiliar information for DECL. */ |
391 | ||
392 | static inline var_info_p | |
393 | get_var_info (tree decl) | |
394 | { | |
395 | struct var_info_d vi; | |
bf190e8d | 396 | var_info_d **slot; |
b4e209fd | 397 | vi.var = decl; |
c203e8a7 | 398 | slot = var_infos->find_slot_with_hash (&vi, DECL_UID (decl), INSERT); |
b4e209fd RG |
399 | if (*slot == NULL) |
400 | { | |
401 | var_info_p v = XCNEW (struct var_info_d); | |
402 | v->var = decl; | |
bf190e8d | 403 | *slot = v; |
b4e209fd RG |
404 | return v; |
405 | } | |
bf190e8d | 406 | return *slot; |
b4e209fd RG |
407 | } |
408 | ||
38635499 DN |
409 | |
410 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
411 | |
412 | static void | |
413 | clear_ssa_name_info (void) | |
414 | { | |
415 | current_info_for_ssa_name_age++; | |
891f2df6 RG |
416 | |
417 | /* If current_info_for_ssa_name_age wraps we use stale information. | |
418 | Asser that this does not happen. */ | |
419 | gcc_assert (current_info_for_ssa_name_age != 0); | |
95dd3097 | 420 | } |
7256233c | 421 | |
38635499 | 422 | |
8812aab1 | 423 | /* Get access to the auxiliar information stored per SSA name or decl. */ |
5f240ec4 | 424 | |
8812aab1 RG |
425 | static inline common_info_p |
426 | get_common_info (tree var) | |
5f240ec4 ZD |
427 | { |
428 | if (TREE_CODE (var) == SSA_NAME) | |
8812aab1 | 429 | return &get_ssa_name_ann (var)->info; |
5f240ec4 | 430 | else |
8812aab1 | 431 | return &get_var_info (var)->info; |
5f240ec4 ZD |
432 | } |
433 | ||
7256233c | 434 | |
5f240ec4 ZD |
435 | /* Return the current definition for VAR. */ |
436 | ||
84d65814 | 437 | tree |
5f240ec4 ZD |
438 | get_current_def (tree var) |
439 | { | |
8812aab1 | 440 | return get_common_info (var)->current_def; |
5f240ec4 ZD |
441 | } |
442 | ||
7256233c | 443 | |
5f240ec4 ZD |
444 | /* Sets current definition of VAR to DEF. */ |
445 | ||
84d65814 | 446 | void |
5f240ec4 ZD |
447 | set_current_def (tree var, tree def) |
448 | { | |
8812aab1 | 449 | get_common_info (var)->current_def = def; |
5f240ec4 ZD |
450 | } |
451 | ||
95dd3097 ZD |
452 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
453 | all statements in basic block BB. */ | |
454 | ||
455 | static void | |
456 | initialize_flags_in_bb (basic_block bb) | |
457 | { | |
726a989a RB |
458 | gimple stmt; |
459 | gimple_stmt_iterator gsi; | |
95dd3097 | 460 | |
726a989a | 461 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 462 | { |
726a989a RB |
463 | gimple phi = gsi_stmt (gsi); |
464 | set_rewrite_uses (phi, false); | |
465 | set_register_defs (phi, false); | |
95dd3097 ZD |
466 | } |
467 | ||
726a989a | 468 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 469 | { |
726a989a RB |
470 | stmt = gsi_stmt (gsi); |
471 | ||
95dd3097 ZD |
472 | /* We are going to use the operand cache API, such as |
473 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
474 | cache for each statement should be up-to-date. */ | |
4ad14919 | 475 | gcc_checking_assert (!gimple_modified_p (stmt)); |
726a989a RB |
476 | set_rewrite_uses (stmt, false); |
477 | set_register_defs (stmt, false); | |
95dd3097 ZD |
478 | } |
479 | } | |
480 | ||
481 | /* Mark block BB as interesting for update_ssa. */ | |
482 | ||
483 | static void | |
484 | mark_block_for_update (basic_block bb) | |
485 | { | |
4ad14919 | 486 | gcc_checking_assert (blocks_to_update != NULL); |
f3cf730b | 487 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
95dd3097 | 488 | return; |
95dd3097 ZD |
489 | initialize_flags_in_bb (bb); |
490 | } | |
491 | ||
7256233c DN |
492 | /* Return the set of blocks where variable VAR is defined and the blocks |
493 | where VAR is live on entry (livein). If no entry is found in | |
494 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 495 | |
7256233c | 496 | static inline struct def_blocks_d * |
8812aab1 | 497 | get_def_blocks_for (common_info_p info) |
6de9cd9a | 498 | { |
8812aab1 | 499 | struct def_blocks_d *db_p = &info->def_blocks; |
b4e209fd | 500 | if (!db_p->def_blocks) |
6de9cd9a | 501 | { |
b4e209fd RG |
502 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
503 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
504 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
a32b97a2 BB |
505 | } |
506 | ||
7256233c | 507 | return db_p; |
6de9cd9a DN |
508 | } |
509 | ||
7d5f9cc6 | 510 | |
5f240ec4 | 511 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 512 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
513 | |
514 | static void | |
0bca51f0 | 515 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a DN |
516 | { |
517 | struct def_blocks_d *db_p; | |
8812aab1 | 518 | common_info_p info; |
34eb8991 | 519 | |
8812aab1 RG |
520 | info = get_common_info (var); |
521 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
522 | |
523 | /* Set the bit corresponding to the block where VAR is defined. */ | |
524 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
525 | if (phi_p) |
526 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 527 | |
7256233c | 528 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
529 | |
530 | If we are in the UNKNOWN state, then this is the first definition | |
531 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 532 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
533 | transition to NEED_PHI_STATE_NO). |
534 | ||
535 | If we are in any other state, then we either have multiple definitions | |
536 | of this variable occurring in different blocks or we saw a use of the | |
537 | variable which was not dominated by the block containing the | |
538 | definition(s). In this case we may need a PHI node, so enter | |
539 | state NEED_PHI_STATE_MAYBE. */ | |
8812aab1 RG |
540 | if (info->need_phi_state == NEED_PHI_STATE_UNKNOWN) |
541 | info->need_phi_state = NEED_PHI_STATE_NO; | |
6de9cd9a | 542 | else |
8812aab1 | 543 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
544 | } |
545 | ||
546 | ||
547 | /* Mark block BB as having VAR live at the entry to BB. */ | |
548 | ||
549 | static void | |
550 | set_livein_block (tree var, basic_block bb) | |
551 | { | |
8812aab1 | 552 | common_info_p info; |
6de9cd9a | 553 | struct def_blocks_d *db_p; |
6de9cd9a | 554 | |
8812aab1 RG |
555 | info = get_common_info (var); |
556 | db_p = get_def_blocks_for (info); | |
6de9cd9a DN |
557 | |
558 | /* Set the bit corresponding to the block where VAR is live in. */ | |
559 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
560 | ||
7256233c | 561 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
562 | |
563 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
564 | by the single block containing the definition(s) of this variable. If | |
565 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
566 | NEED_PHI_STATE_MAYBE. */ | |
8812aab1 | 567 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
6de9cd9a DN |
568 | { |
569 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
570 | ||
571 | if (def_block_index == -1 | |
572 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
06e28de2 | 573 | BASIC_BLOCK_FOR_FN (cfun, def_block_index))) |
8812aab1 | 574 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
575 | } |
576 | else | |
8812aab1 | 577 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
6de9cd9a DN |
578 | } |
579 | ||
580 | ||
0bca51f0 | 581 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
6de9cd9a | 582 | |
0bca51f0 DN |
583 | static inline bool |
584 | is_old_name (tree name) | |
585 | { | |
84d65814 | 586 | unsigned ver = SSA_NAME_VERSION (name); |
c36eadbe | 587 | if (!old_ssa_names) |
5006671f | 588 | return false; |
c36eadbe | 589 | return (ver < SBITMAP_SIZE (old_ssa_names) |
d7c028c0 | 590 | && bitmap_bit_p (old_ssa_names, ver)); |
0bca51f0 DN |
591 | } |
592 | ||
593 | ||
594 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 595 | |
0bca51f0 DN |
596 | static inline bool |
597 | is_new_name (tree name) | |
598 | { | |
84d65814 | 599 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
600 | if (!new_ssa_names) |
601 | return false; | |
5829cc0f | 602 | return (ver < SBITMAP_SIZE (new_ssa_names) |
d7c028c0 | 603 | && bitmap_bit_p (new_ssa_names, ver)); |
6de9cd9a DN |
604 | } |
605 | ||
7256233c | 606 | |
82d6e6fc | 607 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
608 | |
609 | static inline bitmap | |
82d6e6fc | 610 | names_replaced_by (tree new_tree) |
0bca51f0 | 611 | { |
891f2df6 | 612 | return get_ssa_name_ann (new_tree)->repl_set; |
0bca51f0 DN |
613 | } |
614 | ||
615 | ||
82d6e6fc | 616 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
617 | |
618 | static inline void | |
82d6e6fc | 619 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 | 620 | { |
891f2df6 RG |
621 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
622 | if (!*set) | |
623 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
624 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
0bca51f0 DN |
625 | } |
626 | ||
627 | ||
82d6e6fc | 628 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
629 | represents the set of names O_1 ... O_j replaced by N_i. This is |
630 | used by update_ssa and its helpers to introduce new SSA names in an | |
631 | already formed SSA web. */ | |
632 | ||
633 | static void | |
82d6e6fc | 634 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 | 635 | { |
82d6e6fc | 636 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
4ad14919 RG |
637 | gcc_checking_assert (new_tree != old |
638 | && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 639 | |
38635499 DN |
640 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
641 | caller may have created new names since the set was created. */ | |
5829cc0f | 642 | if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1) |
38635499 DN |
643 | { |
644 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
645 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
646 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
647 | } |
648 | ||
0bca51f0 | 649 | /* Update the REPL_TBL table. */ |
82d6e6fc | 650 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 651 | |
0bca51f0 | 652 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 653 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 654 | if (is_new_name (old)) |
82d6e6fc | 655 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 656 | |
82d6e6fc | 657 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 658 | respectively. */ |
d7c028c0 LC |
659 | bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
660 | bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old)); | |
d00ad49b | 661 | } |
6de9cd9a | 662 | |
6de9cd9a | 663 | |
7256233c DN |
664 | /* Call back for walk_dominator_tree used to collect definition sites |
665 | for every variable in the function. For every statement S in block | |
666 | BB: | |
6de9cd9a | 667 | |
f47c96aa | 668 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
ccf5c864 | 669 | KILLS. |
6de9cd9a | 670 | |
7256233c | 671 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 672 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 673 | |
7256233c DN |
674 | This information is used to determine which variables are live |
675 | across block boundaries to reduce the number of PHI nodes | |
676 | we create. */ | |
6de9cd9a | 677 | |
7256233c | 678 | static void |
ccf5c864 | 679 | mark_def_sites (basic_block bb, gimple stmt, bitmap kills) |
7256233c | 680 | { |
726a989a | 681 | tree def; |
7256233c | 682 | use_operand_p use_p; |
7256233c DN |
683 | ssa_op_iter iter; |
684 | ||
726a989a RB |
685 | /* Since this is the first time that we rewrite the program into SSA |
686 | form, force an operand scan on every statement. */ | |
726a989a | 687 | update_stmt (stmt); |
7256233c | 688 | |
4ad14919 | 689 | gcc_checking_assert (blocks_to_update == NULL); |
726a989a RB |
690 | set_register_defs (stmt, false); |
691 | set_rewrite_uses (stmt, false); | |
7256233c | 692 | |
b5b8b0ac | 693 | if (is_gimple_debug (stmt)) |
ddb555ed JJ |
694 | { |
695 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
696 | { | |
697 | tree sym = USE_FROM_PTR (use_p); | |
4ad14919 | 698 | gcc_checking_assert (DECL_P (sym)); |
ddb555ed JJ |
699 | set_rewrite_uses (stmt, true); |
700 | } | |
701 | if (rewrite_uses_p (stmt)) | |
d7c028c0 | 702 | bitmap_set_bit (interesting_blocks, bb->index); |
ddb555ed JJ |
703 | return; |
704 | } | |
b5b8b0ac | 705 | |
7256233c DN |
706 | /* If a variable is used before being set, then the variable is live |
707 | across a block boundary, so mark it live-on-entry to BB. */ | |
39c58b3a | 708 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
7256233c | 709 | { |
0bca51f0 | 710 | tree sym = USE_FROM_PTR (use_p); |
4ad14919 | 711 | gcc_checking_assert (DECL_P (sym)); |
a3648cfc | 712 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 713 | set_livein_block (sym, bb); |
726a989a | 714 | set_rewrite_uses (stmt, true); |
7256233c | 715 | } |
b8698a0f | 716 | |
38635499 DN |
717 | /* Now process the defs. Mark BB as the definition block and add |
718 | each def to the set of killed symbols. */ | |
39c58b3a | 719 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
7256233c | 720 | { |
4ad14919 | 721 | gcc_checking_assert (DECL_P (def)); |
0bca51f0 | 722 | set_def_block (def, bb, false); |
a3648cfc | 723 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 724 | set_register_defs (stmt, true); |
7256233c | 725 | } |
0bca51f0 DN |
726 | |
727 | /* If we found the statement interesting then also mark the block BB | |
728 | as interesting. */ | |
726a989a | 729 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
d7c028c0 | 730 | bitmap_set_bit (interesting_blocks, bb->index); |
7256233c DN |
731 | } |
732 | ||
f074ff6c ZD |
733 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
734 | in the dfs numbering of the dominance tree. */ | |
735 | ||
736 | struct dom_dfsnum | |
737 | { | |
738 | /* Basic block whose index this entry corresponds to. */ | |
739 | unsigned bb_index; | |
740 | ||
741 | /* The dfs number of this node. */ | |
742 | unsigned dfs_num; | |
743 | }; | |
744 | ||
745 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
746 | for qsort. */ | |
747 | ||
748 | static int | |
749 | cmp_dfsnum (const void *a, const void *b) | |
750 | { | |
3d9a9f94 KG |
751 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
752 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
753 | |
754 | return (int) da->dfs_num - (int) db->dfs_num; | |
755 | } | |
756 | ||
757 | /* Among the intervals starting at the N points specified in DEFS, find | |
758 | the one that contains S, and return its bb_index. */ | |
759 | ||
760 | static unsigned | |
761 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
762 | { | |
763 | unsigned f = 0, t = n, m; | |
764 | ||
765 | while (t > f + 1) | |
766 | { | |
767 | m = (f + t) / 2; | |
768 | if (defs[m].dfs_num <= s) | |
769 | f = m; | |
770 | else | |
771 | t = m; | |
772 | } | |
773 | ||
774 | return defs[f].bb_index; | |
775 | } | |
776 | ||
777 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
778 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
779 | ||
780 | static void | |
781 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
782 | { | |
f074ff6c ZD |
783 | bitmap_iterator bi; |
784 | unsigned i, b, p, u, top; | |
785 | bitmap live_phis; | |
786 | basic_block def_bb, use_bb; | |
787 | edge e; | |
788 | edge_iterator ei; | |
789 | bitmap to_remove; | |
790 | struct dom_dfsnum *defs; | |
791 | unsigned n_defs, adef; | |
792 | ||
793 | if (bitmap_empty_p (uses)) | |
794 | { | |
795 | bitmap_clear (phis); | |
796 | return; | |
797 | } | |
798 | ||
799 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
800 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
801 | to_remove = BITMAP_ALLOC (NULL); | |
802 | bitmap_and_compl (to_remove, kills, uses); | |
803 | bitmap_and_compl_into (phis, to_remove); | |
804 | if (bitmap_empty_p (phis)) | |
805 | { | |
806 | BITMAP_FREE (to_remove); | |
807 | return; | |
808 | } | |
809 | ||
810 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
811 | liveness information, as that may be linear in the size of CFG, and if | |
812 | there are lot of different variables to rewrite, this may lead to quadratic | |
813 | behavior. | |
814 | ||
815 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
816 | then for each of them find the nearest def that dominates them. If this | |
817 | def is a phi node, we mark it live, and if it was not live before, we | |
818 | add the predecessors of its basic block to the worklist. | |
b8698a0f | 819 | |
f074ff6c ZD |
820 | To quickly locate the nearest def that dominates use, we use dfs numbering |
821 | of the dominance tree (that is already available in order to speed up | |
822 | queries). For each def, we have the interval given by the dfs number on | |
823 | entry to and on exit from the corresponding subtree in the dominance tree. | |
824 | The nearest dominator for a given use is the smallest of these intervals | |
825 | that contains entry and exit dfs numbers for the basic block with the use. | |
826 | If we store the bounds for all the uses to an array and sort it, we can | |
827 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
828 | bitmap_ior (to_remove, kills, phis); | |
829 | n_defs = bitmap_count_bits (to_remove); | |
830 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
831 | defs[0].bb_index = 1; | |
832 | defs[0].dfs_num = 0; | |
833 | adef = 1; | |
834 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
835 | { | |
06e28de2 | 836 | def_bb = BASIC_BLOCK_FOR_FN (cfun, i); |
f074ff6c ZD |
837 | defs[adef].bb_index = i; |
838 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
839 | defs[adef + 1].bb_index = i; | |
840 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
841 | adef += 2; | |
842 | } | |
843 | BITMAP_FREE (to_remove); | |
844 | gcc_assert (adef == 2 * n_defs + 1); | |
845 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
846 | gcc_assert (defs[0].bb_index == 1); | |
847 | ||
848 | /* Now each DEFS entry contains the number of the basic block to that the | |
849 | dfs number corresponds. Change them to the number of basic block that | |
850 | corresponds to the interval following the dfs number. Also, for the | |
851 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
852 | to the start of the following interval, not to the end of the current | |
853 | one). We use WORKLIST as a stack. */ | |
ef062b13 | 854 | auto_vec<int> worklist (n_defs + 1); |
9771b263 | 855 | worklist.quick_push (1); |
f074ff6c ZD |
856 | top = 1; |
857 | n_defs = 1; | |
858 | for (i = 1; i < adef; i++) | |
859 | { | |
860 | b = defs[i].bb_index; | |
861 | if (b == top) | |
862 | { | |
863 | /* This is a closing element. Interval corresponding to the top | |
864 | of the stack after removing it follows. */ | |
9771b263 DN |
865 | worklist.pop (); |
866 | top = worklist[worklist.length () - 1]; | |
f074ff6c ZD |
867 | defs[n_defs].bb_index = top; |
868 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
869 | } | |
870 | else | |
871 | { | |
872 | /* Opening element. Nothing to do, just push it to the stack and move | |
873 | it to the correct position. */ | |
874 | defs[n_defs].bb_index = defs[i].bb_index; | |
875 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
9771b263 | 876 | worklist.quick_push (b); |
f074ff6c ZD |
877 | top = b; |
878 | } | |
879 | ||
880 | /* If this interval starts at the same point as the previous one, cancel | |
881 | the previous one. */ | |
882 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
883 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
884 | else | |
885 | n_defs++; | |
886 | } | |
9771b263 DN |
887 | worklist.pop (); |
888 | gcc_assert (worklist.is_empty ()); | |
f074ff6c ZD |
889 | |
890 | /* Now process the uses. */ | |
891 | live_phis = BITMAP_ALLOC (NULL); | |
892 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
893 | { | |
9771b263 | 894 | worklist.safe_push (i); |
f074ff6c ZD |
895 | } |
896 | ||
9771b263 | 897 | while (!worklist.is_empty ()) |
f074ff6c | 898 | { |
9771b263 | 899 | b = worklist.pop (); |
f074ff6c ZD |
900 | if (b == ENTRY_BLOCK) |
901 | continue; | |
902 | ||
903 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
904 | find the def that dominates the immediate dominator of USE_BB | |
905 | (the kill in USE_BB does not dominate the use). */ | |
906 | if (bitmap_bit_p (phis, b)) | |
907 | p = b; | |
908 | else | |
909 | { | |
06e28de2 DM |
910 | use_bb = get_immediate_dominator (CDI_DOMINATORS, |
911 | BASIC_BLOCK_FOR_FN (cfun, b)); | |
f074ff6c ZD |
912 | p = find_dfsnum_interval (defs, n_defs, |
913 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
914 | if (!bitmap_bit_p (phis, p)) | |
915 | continue; | |
916 | } | |
917 | ||
918 | /* If the phi node is already live, there is nothing to do. */ | |
fcaa4ca4 | 919 | if (!bitmap_set_bit (live_phis, p)) |
f074ff6c ZD |
920 | continue; |
921 | ||
fcaa4ca4 | 922 | /* Add the new uses to the worklist. */ |
06e28de2 | 923 | def_bb = BASIC_BLOCK_FOR_FN (cfun, p); |
f074ff6c ZD |
924 | FOR_EACH_EDGE (e, ei, def_bb->preds) |
925 | { | |
926 | u = e->src->index; | |
927 | if (bitmap_bit_p (uses, u)) | |
928 | continue; | |
929 | ||
1e5787ef ZD |
930 | /* In case there is a kill directly in the use block, do not record |
931 | the use (this is also necessary for correctness, as we assume that | |
932 | uses dominated by a def directly in their block have been filtered | |
933 | out before). */ | |
934 | if (bitmap_bit_p (kills, u)) | |
935 | continue; | |
936 | ||
f074ff6c | 937 | bitmap_set_bit (uses, u); |
9771b263 | 938 | worklist.safe_push (u); |
f074ff6c ZD |
939 | } |
940 | } | |
941 | ||
f074ff6c ZD |
942 | bitmap_copy (phis, live_phis); |
943 | BITMAP_FREE (live_phis); | |
944 | free (defs); | |
945 | } | |
7256233c | 946 | |
7256233c DN |
947 | /* Return the set of blocks where variable VAR is defined and the blocks |
948 | where VAR is live on entry (livein). Return NULL, if no entry is | |
949 | found in DEF_BLOCKS. */ | |
950 | ||
951 | static inline struct def_blocks_d * | |
952 | find_def_blocks_for (tree var) | |
953 | { | |
8812aab1 | 954 | def_blocks_p p = &get_common_info (var)->def_blocks; |
b4e209fd RG |
955 | if (!p->def_blocks) |
956 | return NULL; | |
957 | return p; | |
7256233c DN |
958 | } |
959 | ||
960 | ||
2ce79879 ZD |
961 | /* Marks phi node PHI in basic block BB for rewrite. */ |
962 | ||
963 | static void | |
538dd0b7 | 964 | mark_phi_for_rewrite (basic_block bb, gphi *phi) |
2ce79879 | 965 | { |
538dd0b7 | 966 | vec<gphi *> phis; |
580b2c2e | 967 | unsigned n, idx = bb->index; |
2ce79879 | 968 | |
726a989a | 969 | if (rewrite_uses_p (phi)) |
2ce79879 | 970 | return; |
38635499 | 971 | |
726a989a | 972 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
973 | |
974 | if (!blocks_with_phis_to_rewrite) | |
975 | return; | |
976 | ||
977 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
580b2c2e | 978 | |
8b1c6fd7 | 979 | n = (unsigned) last_basic_block_for_fn (cfun) + 1; |
9771b263 DN |
980 | if (phis_to_rewrite.length () < n) |
981 | phis_to_rewrite.safe_grow_cleared (n); | |
2ce79879 | 982 | |
9771b263 DN |
983 | phis = phis_to_rewrite[idx]; |
984 | phis.reserve (10); | |
2ce79879 | 985 | |
9771b263 DN |
986 | phis.safe_push (phi); |
987 | phis_to_rewrite[idx] = phis; | |
2ce79879 ZD |
988 | } |
989 | ||
7256233c | 990 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 991 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
992 | function assumes that the caller is incrementally updating the |
993 | existing SSA form, in which case VAR may be an SSA name instead of | |
994 | a symbol. | |
0bca51f0 DN |
995 | |
996 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
997 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
998 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
999 | |
1000 | static void | |
0bca51f0 | 1001 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
1002 | { |
1003 | unsigned bb_index; | |
1004 | edge e; | |
538dd0b7 | 1005 | gphi *phi; |
7256233c DN |
1006 | basic_block bb; |
1007 | bitmap_iterator bi; | |
4ad14919 | 1008 | struct def_blocks_d *def_map = find_def_blocks_for (var); |
7256233c DN |
1009 | |
1010 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
1011 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
1012 | ||
f074ff6c ZD |
1013 | /* Remove obviously useless phi nodes. */ |
1014 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
1015 | def_map->livein_blocks); | |
7256233c DN |
1016 | |
1017 | /* And insert the PHI nodes. */ | |
f074ff6c | 1018 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c | 1019 | { |
06e28de2 | 1020 | bb = BASIC_BLOCK_FOR_FN (cfun, bb_index); |
95dd3097 ZD |
1021 | if (update_p) |
1022 | mark_block_for_update (bb); | |
7256233c | 1023 | |
fa5556de RB |
1024 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1025 | { | |
1026 | fprintf (dump_file, "creating PHI node in block #%d for ", bb_index); | |
1027 | print_generic_expr (dump_file, var, TDF_SLIM); | |
1028 | fprintf (dump_file, "\n"); | |
1029 | } | |
726a989a | 1030 | phi = NULL; |
38635499 DN |
1031 | |
1032 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 1033 | { |
84d65814 DN |
1034 | /* If we are rewriting SSA names, create the LHS of the PHI |
1035 | node by duplicating VAR. This is useful in the case of | |
1036 | pointers, to also duplicate pointer attributes (alias | |
1037 | information, in particular). */ | |
7256233c | 1038 | edge_iterator ei; |
84d65814 | 1039 | tree new_lhs; |
0bca51f0 | 1040 | |
4ad14919 | 1041 | gcc_checking_assert (update_p); |
dcc748dd RG |
1042 | new_lhs = duplicate_ssa_name (var, NULL); |
1043 | phi = create_phi_node (new_lhs, bb); | |
84d65814 | 1044 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1045 | |
1046 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1047 | every argument so that rewrite_update_phi_arguments knows | |
1048 | which name is this PHI node replacing. If VAR is a | |
1049 | symbol marked for renaming, this is not necessary, the | |
1050 | renamer will use the symbol on the LHS to get its | |
1051 | reaching definition. */ | |
7256233c | 1052 | FOR_EACH_EDGE (e, ei, bb->preds) |
9e227d60 | 1053 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
7256233c | 1054 | } |
84d65814 DN |
1055 | else |
1056 | { | |
b5b8b0ac | 1057 | tree tracked_var; |
3a56edc7 | 1058 | |
4ad14919 | 1059 | gcc_checking_assert (DECL_P (var)); |
e24c4814 | 1060 | phi = create_phi_node (var, bb); |
3a56edc7 AO |
1061 | |
1062 | tracked_var = target_for_debug_bind (var); | |
1063 | if (tracked_var) | |
b5b8b0ac AO |
1064 | { |
1065 | gimple note = gimple_build_debug_bind (tracked_var, | |
1066 | PHI_RESULT (phi), | |
1067 | phi); | |
1068 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1069 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1070 | } | |
84d65814 | 1071 | } |
0bca51f0 DN |
1072 | |
1073 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1074 | set_register_defs (phi, true); |
2ce79879 | 1075 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1076 | } |
1077 | } | |
1078 | ||
b4e209fd | 1079 | /* Sort var_infos after DECL_UID of their var. */ |
d9ed2fbd RG |
1080 | |
1081 | static int | |
b4e209fd | 1082 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
d9ed2fbd | 1083 | { |
b4e209fd RG |
1084 | const struct var_info_d *defa = *(struct var_info_d * const *)a; |
1085 | const struct var_info_d *defb = *(struct var_info_d * const *)b; | |
d9ed2fbd RG |
1086 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1087 | return -1; | |
1088 | else | |
1089 | return 1; | |
1090 | } | |
7256233c | 1091 | |
7256233c DN |
1092 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1093 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1094 | the flowgraph. */ |
7256233c DN |
1095 | |
1096 | static void | |
0fc555fb | 1097 | insert_phi_nodes (bitmap_head *dfs) |
7256233c | 1098 | { |
c203e8a7 | 1099 | hash_table<var_info_hasher>::iterator hi; |
d9ed2fbd | 1100 | unsigned i; |
b4e209fd | 1101 | var_info_p info; |
7256233c DN |
1102 | |
1103 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
b8698a0f | 1104 | |
c203e8a7 TS |
1105 | auto_vec<var_info_p> vars (var_infos->elements ()); |
1106 | FOR_EACH_HASH_TABLE_ELEMENT (*var_infos, info, var_info_p, hi) | |
8812aab1 | 1107 | if (info->info.need_phi_state != NEED_PHI_STATE_NO) |
9771b263 | 1108 | vars.quick_push (info); |
d9ed2fbd | 1109 | |
e68c7b43 RG |
1110 | /* Do two stages to avoid code generation differences for UID |
1111 | differences but no UID ordering differences. */ | |
9771b263 | 1112 | vars.qsort (insert_phi_nodes_compare_var_infos); |
e68c7b43 | 1113 | |
9771b263 | 1114 | FOR_EACH_VEC_ELT (vars, i, info) |
5f240ec4 | 1115 | { |
8812aab1 | 1116 | bitmap idf = compute_idf (info->info.def_blocks.def_blocks, dfs); |
b4e209fd | 1117 | insert_phi_nodes_for (info->var, idf, false); |
e68c7b43 RG |
1118 | BITMAP_FREE (idf); |
1119 | } | |
1120 | ||
6de9cd9a DN |
1121 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1122 | } | |
1123 | ||
1124 | ||
38635499 DN |
1125 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1126 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1127 | |
cfaab3a9 | 1128 | static void |
38635499 | 1129 | register_new_def (tree def, tree sym) |
7256233c | 1130 | { |
8812aab1 | 1131 | common_info_p info = get_common_info (sym); |
7256233c | 1132 | tree currdef; |
b8698a0f | 1133 | |
7256233c DN |
1134 | /* If this variable is set in a single basic block and all uses are |
1135 | dominated by the set(s) in that single basic block, then there is | |
1136 | no reason to record anything for this variable in the block local | |
1137 | definition stacks. Doing so just wastes time and memory. | |
1138 | ||
1139 | This is the same test to prune the set of variables which may | |
1140 | need PHI nodes. So we just use that information since it's already | |
1141 | computed and available for us to use. */ | |
8812aab1 | 1142 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
7256233c | 1143 | { |
8812aab1 | 1144 | info->current_def = def; |
7256233c DN |
1145 | return; |
1146 | } | |
1147 | ||
8812aab1 | 1148 | currdef = info->current_def; |
7256233c | 1149 | |
38635499 DN |
1150 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1151 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1152 | in the stack so that we know which symbol is being defined by | |
1153 | this SSA name when we unwind the stack. */ | |
1154 | if (currdef && !is_gimple_reg (sym)) | |
9771b263 | 1155 | block_defs_stack.safe_push (sym); |
7256233c | 1156 | |
38635499 DN |
1157 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1158 | stack is later used by the dominator tree callbacks to restore | |
1159 | the reaching definitions for all the variables defined in the | |
1160 | block after a recursive visit to all its immediately dominated | |
1161 | blocks. If there is no current reaching definition, then just | |
1162 | record the underlying _DECL node. */ | |
9771b263 | 1163 | block_defs_stack.safe_push (currdef ? currdef : sym); |
38635499 DN |
1164 | |
1165 | /* Set the current reaching definition for SYM to be DEF. */ | |
8812aab1 | 1166 | info->current_def = def; |
7256233c DN |
1167 | } |
1168 | ||
1169 | ||
6de9cd9a DN |
1170 | /* Perform a depth-first traversal of the dominator tree looking for |
1171 | variables to rename. BB is the block where to start searching. | |
1172 | Renaming is a five step process: | |
1173 | ||
1174 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1175 | registered as the current definition for the corresponding variable. | |
1176 | ||
1177 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1178 | rewritten with their corresponding reaching definition. DEF and | |
1179 | VDEF targets are registered as new definitions. | |
b8698a0f | 1180 | |
6de9cd9a DN |
1181 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1182 | argument corresponding to BB is replaced with its current reaching | |
1183 | definition. | |
1184 | ||
1185 | 4- Recursively rewrite every dominator child block of BB. | |
1186 | ||
1187 | 5- Restore (in reverse order) the current reaching definition for every | |
1188 | new definition introduced in this block. This is done so that when | |
1189 | we return from the recursive call, all the current reaching | |
1190 | definitions are restored to the names that were valid in the | |
1191 | dominator parent of BB. */ | |
1192 | ||
7256233c | 1193 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1194 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1195 | |
7256233c DN |
1196 | static tree |
1197 | get_reaching_def (tree var) | |
1198 | { | |
8812aab1 | 1199 | common_info_p info = get_common_info (var); |
38635499 | 1200 | tree currdef; |
b8698a0f | 1201 | |
7256233c | 1202 | /* Lookup the current reaching definition for VAR. */ |
8812aab1 | 1203 | currdef = info->current_def; |
5f240ec4 | 1204 | |
7256233c DN |
1205 | /* If there is no reaching definition for VAR, create and register a |
1206 | default definition for it (if needed). */ | |
38635499 | 1207 | if (currdef == NULL_TREE) |
7256233c | 1208 | { |
38635499 | 1209 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
32244553 | 1210 | currdef = get_or_create_ssa_default_def (cfun, sym); |
7256233c DN |
1211 | } |
1212 | ||
1213 | /* Return the current reaching definition for VAR, or the default | |
1214 | definition, if we had to create one. */ | |
38635499 | 1215 | return currdef; |
7256233c DN |
1216 | } |
1217 | ||
1218 | ||
ddb555ed JJ |
1219 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1220 | ||
1221 | static void | |
1222 | rewrite_debug_stmt_uses (gimple stmt) | |
1223 | { | |
1224 | use_operand_p use_p; | |
1225 | ssa_op_iter iter; | |
1226 | bool update = false; | |
1227 | ||
1228 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1229 | { | |
5f564b8f | 1230 | tree var = USE_FROM_PTR (use_p), def; |
8812aab1 | 1231 | common_info_p info = get_common_info (var); |
4ad14919 | 1232 | gcc_checking_assert (DECL_P (var)); |
8812aab1 | 1233 | def = info->current_def; |
5f564b8f | 1234 | if (!def) |
ddb555ed | 1235 | { |
fefa31b5 DM |
1236 | if (TREE_CODE (var) == PARM_DECL |
1237 | && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun))) | |
ddb555ed JJ |
1238 | { |
1239 | gimple_stmt_iterator gsi | |
fefa31b5 DM |
1240 | = |
1241 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1242 | int lim; |
1243 | /* Search a few source bind stmts at the start of first bb to | |
1244 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1245 | for (lim = 32; | |
1246 | !gsi_end_p (gsi) && lim > 0; | |
1247 | gsi_next (&gsi), lim--) | |
1248 | { | |
1249 | gimple gstmt = gsi_stmt (gsi); | |
1250 | if (!gimple_debug_source_bind_p (gstmt)) | |
1251 | break; | |
1252 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1253 | { | |
1254 | def = gimple_debug_source_bind_get_var (gstmt); | |
1255 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1256 | break; | |
1257 | else | |
1258 | def = NULL_TREE; | |
1259 | } | |
1260 | } | |
1261 | /* If not, add a new source bind stmt. */ | |
1262 | if (def == NULL_TREE) | |
1263 | { | |
1264 | gimple def_temp; | |
1265 | def = make_node (DEBUG_EXPR_DECL); | |
1266 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1267 | DECL_ARTIFICIAL (def) = 1; | |
1268 | TREE_TYPE (def) = TREE_TYPE (var); | |
1269 | DECL_MODE (def) = DECL_MODE (var); | |
fefa31b5 DM |
1270 | gsi = |
1271 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
ddb555ed JJ |
1272 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); |
1273 | } | |
1274 | update = true; | |
1275 | } | |
1276 | } | |
1277 | else | |
15923c25 | 1278 | { |
8812aab1 | 1279 | /* Check if info->current_def can be trusted. */ |
5f564b8f MM |
1280 | basic_block bb = gimple_bb (stmt); |
1281 | basic_block def_bb | |
1282 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1283 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1284 | ||
1285 | /* If definition is in current bb, it is fine. */ | |
1286 | if (bb == def_bb) | |
1287 | ; | |
1288 | /* If definition bb doesn't dominate the current bb, | |
1289 | it can't be used. */ | |
1290 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1291 | def = NULL; | |
1292 | /* If there is just one definition and dominates the current | |
1293 | bb, it is fine. */ | |
8812aab1 | 1294 | else if (info->need_phi_state == NEED_PHI_STATE_NO) |
5f564b8f MM |
1295 | ; |
1296 | else | |
15923c25 | 1297 | { |
8812aab1 | 1298 | struct def_blocks_d *db_p = get_def_blocks_for (info); |
15923c25 | 1299 | |
5f564b8f MM |
1300 | /* If there are some non-debug uses in the current bb, |
1301 | it is fine. */ | |
1302 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
15923c25 | 1303 | ; |
5f564b8f | 1304 | /* Otherwise give up for now. */ |
15923c25 | 1305 | else |
5f564b8f | 1306 | def = NULL; |
15923c25 JJ |
1307 | } |
1308 | } | |
ddb555ed JJ |
1309 | if (def == NULL) |
1310 | { | |
1311 | gimple_debug_bind_reset_value (stmt); | |
1312 | update_stmt (stmt); | |
1313 | return; | |
1314 | } | |
1315 | SET_USE (use_p, def); | |
1316 | } | |
1317 | if (update) | |
1318 | update_stmt (stmt); | |
1319 | } | |
1320 | ||
7256233c DN |
1321 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1322 | the block with its immediate reaching definitions. Update the current | |
1323 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1324 | |
1325 | static void | |
5f33a4fc | 1326 | rewrite_stmt (gimple_stmt_iterator *si) |
5f240ec4 | 1327 | { |
7256233c DN |
1328 | use_operand_p use_p; |
1329 | def_operand_p def_p; | |
1330 | ssa_op_iter iter; | |
5f33a4fc | 1331 | gimple stmt = gsi_stmt (*si); |
7256233c | 1332 | |
7256233c DN |
1333 | /* If mark_def_sites decided that we don't need to rewrite this |
1334 | statement, ignore it. */ | |
95dd3097 | 1335 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1336 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1337 | return; |
5f240ec4 ZD |
1338 | |
1339 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1340 | { |
1341 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1342 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1343 | fprintf (dump_file, "\n"); |
1344 | } | |
5f240ec4 | 1345 | |
38635499 | 1346 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1347 | if (rewrite_uses_p (stmt)) |
ddb555ed JJ |
1348 | { |
1349 | if (is_gimple_debug (stmt)) | |
1350 | rewrite_debug_stmt_uses (stmt); | |
1351 | else | |
39c58b3a | 1352 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
ddb555ed JJ |
1353 | { |
1354 | tree var = USE_FROM_PTR (use_p); | |
4ad14919 | 1355 | gcc_checking_assert (DECL_P (var)); |
ddb555ed JJ |
1356 | SET_USE (use_p, get_reaching_def (var)); |
1357 | } | |
1358 | } | |
5f240ec4 | 1359 | |
38635499 | 1360 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1361 | if (register_defs_p (stmt)) |
39c58b3a | 1362 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
1363 | { |
1364 | tree var = DEF_FROM_PTR (def_p); | |
5f33a4fc | 1365 | tree name; |
b5b8b0ac | 1366 | tree tracked_var; |
5f33a4fc | 1367 | |
4ad14919 | 1368 | gcc_checking_assert (DECL_P (var)); |
5f33a4fc RG |
1369 | |
1370 | if (gimple_clobber_p (stmt) | |
1371 | && is_gimple_reg (var)) | |
1372 | { | |
1373 | /* If we rewrite a DECL into SSA form then drop its | |
1374 | clobber stmts and replace uses with a new default def. */ | |
4ad14919 RG |
1375 | gcc_checking_assert (TREE_CODE (var) == VAR_DECL |
1376 | && !gimple_vdef (stmt)); | |
5f33a4fc RG |
1377 | gsi_replace (si, gimple_build_nop (), true); |
1378 | register_new_def (get_or_create_ssa_default_def (cfun, var), var); | |
1379 | break; | |
1380 | } | |
1381 | ||
1382 | name = make_ssa_name (var, stmt); | |
b5b8b0ac | 1383 | SET_DEF (def_p, name); |
38635499 | 1384 | register_new_def (DEF_FROM_PTR (def_p), var); |
b5b8b0ac AO |
1385 | |
1386 | tracked_var = target_for_debug_bind (var); | |
1387 | if (tracked_var) | |
1388 | { | |
1389 | gimple note = gimple_build_debug_bind (tracked_var, name, stmt); | |
5f33a4fc | 1390 | gsi_insert_after (si, note, GSI_SAME_STMT); |
b5b8b0ac | 1391 | } |
0bca51f0 | 1392 | } |
5f240ec4 | 1393 | } |
6de9cd9a | 1394 | |
7256233c | 1395 | |
6de9cd9a DN |
1396 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1397 | PHI nodes. For every PHI node found, add a new argument containing the | |
1398 | current reaching definition for the variable and the edge through which | |
471854f8 | 1399 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1400 | |
1401 | static void | |
ccf5c864 | 1402 | rewrite_add_phi_arguments (basic_block bb) |
6de9cd9a DN |
1403 | { |
1404 | edge e; | |
628f6a4e | 1405 | edge_iterator ei; |
6de9cd9a | 1406 | |
628f6a4e | 1407 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1408 | { |
538dd0b7 DM |
1409 | gphi *phi; |
1410 | gphi_iterator gsi; | |
6de9cd9a | 1411 | |
726a989a RB |
1412 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1413 | gsi_next (&gsi)) | |
6de9cd9a | 1414 | { |
ffc5b2bb RB |
1415 | tree currdef, res; |
1416 | location_t loc; | |
f5045c96 | 1417 | |
538dd0b7 | 1418 | phi = gsi.phi (); |
ffc5b2bb RB |
1419 | res = gimple_phi_result (phi); |
1420 | currdef = get_reaching_def (SSA_NAME_VAR (res)); | |
1421 | /* Virtual operand PHI args do not need a location. */ | |
1422 | if (virtual_operand_p (res)) | |
1423 | loc = UNKNOWN_LOCATION; | |
1424 | else | |
1425 | loc = gimple_location (SSA_NAME_DEF_STMT (currdef)); | |
1426 | add_phi_arg (phi, currdef, e, loc); | |
6de9cd9a DN |
1427 | } |
1428 | } | |
1429 | } | |
1430 | ||
4d9192b5 TS |
1431 | class rewrite_dom_walker : public dom_walker |
1432 | { | |
1433 | public: | |
1434 | rewrite_dom_walker (cdi_direction direction) : dom_walker (direction) {} | |
1435 | ||
1436 | virtual void before_dom_children (basic_block); | |
1437 | virtual void after_dom_children (basic_block); | |
1438 | }; | |
1439 | ||
ccf5c864 PB |
1440 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1441 | of reaching definitions for new SSA names produced in this block | |
1442 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1443 | block. */ | |
1444 | ||
4d9192b5 TS |
1445 | void |
1446 | rewrite_dom_walker::before_dom_children (basic_block bb) | |
ccf5c864 | 1447 | { |
ccf5c864 PB |
1448 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1449 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1450 | ||
1451 | /* Mark the unwind point for this block. */ | |
9771b263 | 1452 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
1453 | |
1454 | /* Step 1. Register new definitions for every PHI node in the block. | |
1455 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1456 | node introduces a new version for the associated variable. */ | |
538dd0b7 DM |
1457 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1458 | gsi_next (&gsi)) | |
ccf5c864 | 1459 | { |
39c58b3a | 1460 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
ccf5c864 PB |
1461 | register_new_def (result, SSA_NAME_VAR (result)); |
1462 | } | |
1463 | ||
1464 | /* Step 2. Rewrite every variable used in each statement in the block | |
1465 | with its immediate reaching definitions. Update the current definition | |
1466 | of a variable when a new real or virtual definition is found. */ | |
d7c028c0 | 1467 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
538dd0b7 DM |
1468 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1469 | gsi_next (&gsi)) | |
5f33a4fc | 1470 | rewrite_stmt (&gsi); |
ccf5c864 PB |
1471 | |
1472 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1473 | For every PHI node found, add a new argument containing the current | |
1474 | reaching definition for the variable and the edge through which that | |
1475 | definition is reaching the PHI node. */ | |
1476 | rewrite_add_phi_arguments (bb); | |
1477 | } | |
1478 | ||
1479 | ||
7256233c | 1480 | |
38635499 DN |
1481 | /* Called after visiting all the statements in basic block BB and all |
1482 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a | 1483 | |
4d9192b5 TS |
1484 | void |
1485 | rewrite_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
6de9cd9a | 1486 | { |
9fae925b | 1487 | /* Restore CURRDEFS to its original state. */ |
9771b263 | 1488 | while (block_defs_stack.length () > 0) |
6de9cd9a | 1489 | { |
9771b263 | 1490 | tree tmp = block_defs_stack.pop (); |
6de9cd9a DN |
1491 | tree saved_def, var; |
1492 | ||
9fae925b JL |
1493 | if (tmp == NULL_TREE) |
1494 | break; | |
1495 | ||
6de9cd9a DN |
1496 | if (TREE_CODE (tmp) == SSA_NAME) |
1497 | { | |
38635499 DN |
1498 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1499 | current definition of its underlying variable. Note that | |
1500 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1501 | being defined is stored in the next slot in the stack. | |
1502 | This mechanism is needed because an SSA name for a | |
1503 | non-register symbol may be the definition for more than | |
1504 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1505 | saved_def = tmp; |
1506 | var = SSA_NAME_VAR (saved_def); | |
38635499 | 1507 | if (!is_gimple_reg (var)) |
9771b263 | 1508 | var = block_defs_stack.pop (); |
6de9cd9a DN |
1509 | } |
1510 | else | |
1511 | { | |
38635499 DN |
1512 | /* If we recorded anything else, it must have been a _DECL |
1513 | node and its current reaching definition must have been | |
1514 | NULL. */ | |
6de9cd9a DN |
1515 | saved_def = NULL; |
1516 | var = tmp; | |
1517 | } | |
b8698a0f | 1518 | |
8812aab1 | 1519 | get_common_info (var)->current_def = saved_def; |
6de9cd9a DN |
1520 | } |
1521 | } | |
1522 | ||
1523 | ||
38635499 DN |
1524 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1525 | ||
24e47c76 | 1526 | DEBUG_FUNCTION void |
38635499 DN |
1527 | debug_decl_set (bitmap set) |
1528 | { | |
1529 | dump_decl_set (stderr, set); | |
5006671f | 1530 | fprintf (stderr, "\n"); |
38635499 DN |
1531 | } |
1532 | ||
1533 | ||
1534 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1535 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1536 | dumped. New levels are created when the dominator tree traversal | |
1537 | used for renaming enters a new sub-tree. */ | |
1538 | ||
1539 | void | |
1540 | dump_defs_stack (FILE *file, int n) | |
1541 | { | |
1542 | int i, j; | |
1543 | ||
1544 | fprintf (file, "\n\nRenaming stack"); | |
1545 | if (n > 0) | |
1546 | fprintf (file, " (up to %d levels)", n); | |
1547 | fprintf (file, "\n\n"); | |
1548 | ||
1549 | i = 1; | |
1550 | fprintf (file, "Level %d (current level)\n", i); | |
9771b263 | 1551 | for (j = (int) block_defs_stack.length () - 1; j >= 0; j--) |
38635499 DN |
1552 | { |
1553 | tree name, var; | |
b8698a0f | 1554 | |
9771b263 | 1555 | name = block_defs_stack[j]; |
38635499 DN |
1556 | if (name == NULL_TREE) |
1557 | { | |
1558 | i++; | |
1559 | if (n > 0 && i > n) | |
1560 | break; | |
1561 | fprintf (file, "\nLevel %d\n", i); | |
1562 | continue; | |
1563 | } | |
1564 | ||
1565 | if (DECL_P (name)) | |
1566 | { | |
1567 | var = name; | |
1568 | name = NULL_TREE; | |
1569 | } | |
1570 | else | |
1571 | { | |
1572 | var = SSA_NAME_VAR (name); | |
1573 | if (!is_gimple_reg (var)) | |
1574 | { | |
1575 | j--; | |
9771b263 | 1576 | var = block_defs_stack[j]; |
38635499 DN |
1577 | } |
1578 | } | |
1579 | ||
1580 | fprintf (file, " Previous CURRDEF ("); | |
1581 | print_generic_expr (file, var, 0); | |
1582 | fprintf (file, ") = "); | |
1583 | if (name) | |
1584 | print_generic_expr (file, name, 0); | |
1585 | else | |
1586 | fprintf (file, "<NIL>"); | |
1587 | fprintf (file, "\n"); | |
1588 | } | |
1589 | } | |
1590 | ||
1591 | ||
1592 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1593 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1594 | dumped. New levels are created when the dominator tree traversal | |
1595 | used for renaming enters a new sub-tree. */ | |
1596 | ||
24e47c76 | 1597 | DEBUG_FUNCTION void |
38635499 DN |
1598 | debug_defs_stack (int n) |
1599 | { | |
1600 | dump_defs_stack (stderr, n); | |
1601 | } | |
1602 | ||
1603 | ||
1604 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1605 | ||
1606 | void | |
1607 | dump_currdefs (FILE *file) | |
1608 | { | |
13714310 | 1609 | unsigned i; |
38635499 DN |
1610 | tree var; |
1611 | ||
9771b263 | 1612 | if (symbols_to_rename.is_empty ()) |
13714310 RG |
1613 | return; |
1614 | ||
38635499 | 1615 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
9771b263 | 1616 | FOR_EACH_VEC_ELT (symbols_to_rename, i, var) |
13714310 | 1617 | { |
8812aab1 | 1618 | common_info_p info = get_common_info (var); |
13714310 RG |
1619 | fprintf (file, "CURRDEF ("); |
1620 | print_generic_expr (file, var, 0); | |
1621 | fprintf (file, ") = "); | |
8812aab1 RG |
1622 | if (info->current_def) |
1623 | print_generic_expr (file, info->current_def, 0); | |
13714310 RG |
1624 | else |
1625 | fprintf (file, "<NIL>"); | |
1626 | fprintf (file, "\n"); | |
1627 | } | |
38635499 DN |
1628 | } |
1629 | ||
1630 | ||
1631 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1632 | ||
24e47c76 | 1633 | DEBUG_FUNCTION void |
38635499 DN |
1634 | debug_currdefs (void) |
1635 | { | |
1636 | dump_currdefs (stderr); | |
1637 | } | |
1638 | ||
1639 | ||
6de9cd9a DN |
1640 | /* Dump SSA information to FILE. */ |
1641 | ||
1642 | void | |
1643 | dump_tree_ssa (FILE *file) | |
1644 | { | |
6de9cd9a | 1645 | const char *funcname |
673fda6b | 1646 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1647 | |
38635499 | 1648 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1649 | |
b4e209fd | 1650 | dump_var_infos (file); |
38635499 DN |
1651 | dump_defs_stack (file, -1); |
1652 | dump_currdefs (file); | |
1653 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1654 | } |
1655 | ||
1656 | ||
1657 | /* Dump SSA information to stderr. */ | |
1658 | ||
24e47c76 | 1659 | DEBUG_FUNCTION void |
6de9cd9a DN |
1660 | debug_tree_ssa (void) |
1661 | { | |
1662 | dump_tree_ssa (stderr); | |
1663 | } | |
1664 | ||
1665 | ||
7256233c DN |
1666 | /* Dump statistics for the hash table HTAB. */ |
1667 | ||
1668 | static void | |
c203e8a7 | 1669 | htab_statistics (FILE *file, const hash_table<var_info_hasher> &htab) |
7256233c DN |
1670 | { |
1671 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
bf190e8d LC |
1672 | (long) htab.size (), |
1673 | (long) htab.elements (), | |
1674 | htab.collisions ()); | |
7256233c DN |
1675 | } |
1676 | ||
1677 | ||
6de9cd9a DN |
1678 | /* Dump SSA statistics on FILE. */ |
1679 | ||
1680 | void | |
1681 | dump_tree_ssa_stats (FILE *file) | |
1682 | { | |
c203e8a7 | 1683 | if (var_infos) |
38635499 | 1684 | { |
b4e209fd RG |
1685 | fprintf (file, "\nHash table statistics:\n"); |
1686 | fprintf (file, " var_infos: "); | |
c203e8a7 | 1687 | htab_statistics (file, *var_infos); |
b4e209fd | 1688 | fprintf (file, "\n"); |
38635499 | 1689 | } |
6de9cd9a DN |
1690 | } |
1691 | ||
1692 | ||
1693 | /* Dump SSA statistics on stderr. */ | |
1694 | ||
24e47c76 | 1695 | DEBUG_FUNCTION void |
6de9cd9a DN |
1696 | debug_tree_ssa_stats (void) |
1697 | { | |
1698 | dump_tree_ssa_stats (stderr); | |
1699 | } | |
1700 | ||
1701 | ||
b4e209fd | 1702 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
6de9cd9a | 1703 | |
bf190e8d LC |
1704 | int |
1705 | debug_var_infos_r (var_info_d **slot, FILE *file) | |
7256233c | 1706 | { |
bf190e8d | 1707 | struct var_info_d *info = *slot; |
b8698a0f | 1708 | |
38635499 | 1709 | fprintf (file, "VAR: "); |
8812aab1 RG |
1710 | print_generic_expr (file, info->var, dump_flags); |
1711 | bitmap_print (file, info->info.def_blocks.def_blocks, | |
1712 | ", DEF_BLOCKS: { ", "}"); | |
1713 | bitmap_print (file, info->info.def_blocks.livein_blocks, | |
1714 | ", LIVEIN_BLOCKS: { ", "}"); | |
1715 | bitmap_print (file, info->info.def_blocks.phi_blocks, | |
1716 | ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1717 | |
7256233c DN |
1718 | return 1; |
1719 | } | |
6de9cd9a | 1720 | |
6de9cd9a | 1721 | |
b4e209fd | 1722 | /* Dump the VAR_INFOS hash table on FILE. */ |
38635499 DN |
1723 | |
1724 | void | |
b4e209fd | 1725 | dump_var_infos (FILE *file) |
38635499 DN |
1726 | { |
1727 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
c203e8a7 TS |
1728 | if (var_infos) |
1729 | var_infos->traverse <FILE *, debug_var_infos_r> (file); | |
38635499 DN |
1730 | } |
1731 | ||
1732 | ||
b4e209fd | 1733 | /* Dump the VAR_INFOS hash table on stderr. */ |
6de9cd9a | 1734 | |
24e47c76 | 1735 | DEBUG_FUNCTION void |
b4e209fd | 1736 | debug_var_infos (void) |
7256233c | 1737 | { |
b4e209fd | 1738 | dump_var_infos (stderr); |
7256233c | 1739 | } |
6de9cd9a | 1740 | |
5f240ec4 | 1741 | |
0bca51f0 | 1742 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1743 | |
0bca51f0 DN |
1744 | static inline void |
1745 | register_new_update_single (tree new_name, tree old_name) | |
1746 | { | |
8812aab1 RG |
1747 | common_info_p info = get_common_info (old_name); |
1748 | tree currdef = info->current_def; | |
5f240ec4 | 1749 | |
38635499 | 1750 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1751 | This stack is later used by the dominator tree callbacks to |
1752 | restore the reaching definitions for all the variables | |
1753 | defined in the block after a recursive visit to all its | |
1754 | immediately dominated blocks. */ | |
9771b263 DN |
1755 | block_defs_stack.reserve (2); |
1756 | block_defs_stack.quick_push (currdef); | |
1757 | block_defs_stack.quick_push (old_name); | |
5f240ec4 | 1758 | |
0bca51f0 DN |
1759 | /* Set the current reaching definition for OLD_NAME to be |
1760 | NEW_NAME. */ | |
8812aab1 | 1761 | info->current_def = new_name; |
0bca51f0 | 1762 | } |
7256233c | 1763 | |
6de9cd9a | 1764 | |
0bca51f0 DN |
1765 | /* Register NEW_NAME to be the new reaching definition for all the |
1766 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1767 | replace old SSA names with new ones. */ | |
7256233c | 1768 | |
0bca51f0 DN |
1769 | static inline void |
1770 | register_new_update_set (tree new_name, bitmap old_names) | |
1771 | { | |
1772 | bitmap_iterator bi; | |
1773 | unsigned i; | |
7256233c | 1774 | |
0bca51f0 DN |
1775 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1776 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1777 | } |
1778 | ||
7256233c | 1779 | |
0bca51f0 | 1780 | |
84d65814 DN |
1781 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1782 | it is a symbol marked for renaming, replace it with USE_P's current | |
1783 | reaching definition. */ | |
1784 | ||
1785 | static inline void | |
1786 | maybe_replace_use (use_operand_p use_p) | |
1787 | { | |
1788 | tree rdef = NULL_TREE; | |
1789 | tree use = USE_FROM_PTR (use_p); | |
1790 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1791 | ||
13714310 | 1792 | if (marked_for_renaming (sym)) |
84d65814 DN |
1793 | rdef = get_reaching_def (sym); |
1794 | else if (is_old_name (use)) | |
1795 | rdef = get_reaching_def (use); | |
1796 | ||
1797 | if (rdef && rdef != use) | |
1798 | SET_USE (use_p, rdef); | |
1799 | } | |
1800 | ||
1801 | ||
b5b8b0ac AO |
1802 | /* Same as maybe_replace_use, but without introducing default stmts, |
1803 | returning false to indicate a need to do so. */ | |
1804 | ||
1805 | static inline bool | |
1806 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1807 | { | |
1808 | tree rdef = NULL_TREE; | |
1809 | tree use = USE_FROM_PTR (use_p); | |
1810 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1811 | ||
13714310 | 1812 | if (marked_for_renaming (sym)) |
8812aab1 | 1813 | rdef = get_var_info (sym)->info.current_def; |
b5b8b0ac AO |
1814 | else if (is_old_name (use)) |
1815 | { | |
8812aab1 | 1816 | rdef = get_ssa_name_ann (use)->info.current_def; |
b5b8b0ac AO |
1817 | /* We can't assume that, if there's no current definition, the |
1818 | default one should be used. It could be the case that we've | |
1819 | rearranged blocks so that the earlier definition no longer | |
1820 | dominates the use. */ | |
1821 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1822 | rdef = use; | |
1823 | } | |
1824 | else | |
1825 | rdef = use; | |
1826 | ||
1827 | if (rdef && rdef != use) | |
1828 | SET_USE (use_p, rdef); | |
1829 | ||
1830 | return rdef != NULL_TREE; | |
1831 | } | |
1832 | ||
1833 | ||
84d65814 DN |
1834 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1835 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1836 | register it as the current definition for the names replaced by | |
956623c1 | 1837 | DEF_P. Returns whether the statement should be removed. */ |
84d65814 | 1838 | |
956623c1 | 1839 | static inline bool |
3a56edc7 AO |
1840 | maybe_register_def (def_operand_p def_p, gimple stmt, |
1841 | gimple_stmt_iterator gsi) | |
84d65814 DN |
1842 | { |
1843 | tree def = DEF_FROM_PTR (def_p); | |
1844 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
956623c1 | 1845 | bool to_delete = false; |
84d65814 | 1846 | |
38635499 DN |
1847 | /* If DEF is a naked symbol that needs renaming, create a new |
1848 | name for it. */ | |
13714310 | 1849 | if (marked_for_renaming (sym)) |
84d65814 DN |
1850 | { |
1851 | if (DECL_P (def)) | |
1852 | { | |
956623c1 MG |
1853 | if (gimple_clobber_p (stmt) && is_gimple_reg (sym)) |
1854 | { | |
1855 | gcc_checking_assert (TREE_CODE (sym) == VAR_DECL); | |
1856 | /* Replace clobber stmts with a default def. This new use of a | |
1857 | default definition may make it look like SSA_NAMEs have | |
1858 | conflicting lifetimes, so we need special code to let them | |
1859 | coalesce properly. */ | |
1860 | to_delete = true; | |
1861 | def = get_or_create_ssa_default_def (cfun, sym); | |
1862 | } | |
1863 | else | |
1864 | def = make_ssa_name (def, stmt); | |
84d65814 | 1865 | SET_DEF (def_p, def); |
3a56edc7 | 1866 | |
956623c1 | 1867 | tree tracked_var = target_for_debug_bind (sym); |
3a56edc7 AO |
1868 | if (tracked_var) |
1869 | { | |
1870 | gimple note = gimple_build_debug_bind (tracked_var, def, stmt); | |
c47987fa JJ |
1871 | /* If stmt ends the bb, insert the debug stmt on the single |
1872 | non-EH edge from the stmt. */ | |
1873 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1874 | { | |
1875 | basic_block bb = gsi_bb (gsi); | |
1876 | edge_iterator ei; | |
1877 | edge e, ef = NULL; | |
1878 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1879 | if (!(e->flags & EDGE_EH)) | |
1880 | { | |
4ad14919 | 1881 | gcc_checking_assert (!ef); |
c47987fa JJ |
1882 | ef = e; |
1883 | } | |
23d5ed5d AO |
1884 | /* If there are other predecessors to ef->dest, then |
1885 | there must be PHI nodes for the modified | |
1886 | variable, and therefore there will be debug bind | |
1887 | stmts after the PHI nodes. The debug bind notes | |
1888 | we'd insert would force the creation of a new | |
1889 | block (diverging codegen) and be redundant with | |
1890 | the post-PHI bind stmts, so don't add them. | |
1891 | ||
1892 | As for the exit edge, there wouldn't be redundant | |
1893 | bind stmts, but there wouldn't be a PC to bind | |
1894 | them to either, so avoid diverging the CFG. */ | |
1895 | if (ef && single_pred_p (ef->dest) | |
fefa31b5 | 1896 | && ef->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
23d5ed5d AO |
1897 | { |
1898 | /* If there were PHI nodes in the node, we'd | |
1899 | have to make sure the value we're binding | |
1900 | doesn't need rewriting. But there shouldn't | |
1901 | be PHI nodes in a single-predecessor block, | |
1902 | so we just add the note. */ | |
1903 | gsi_insert_on_edge_immediate (ef, note); | |
1904 | } | |
c47987fa JJ |
1905 | } |
1906 | else | |
1907 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
3a56edc7 | 1908 | } |
84d65814 DN |
1909 | } |
1910 | ||
1911 | register_new_update_single (def, sym); | |
1912 | } | |
1913 | else | |
1914 | { | |
1915 | /* If DEF is a new name, register it as a new definition | |
1916 | for all the names replaced by DEF. */ | |
1917 | if (is_new_name (def)) | |
1918 | register_new_update_set (def, names_replaced_by (def)); | |
1919 | ||
1920 | /* If DEF is an old name, register DEF as a new | |
1921 | definition for itself. */ | |
1922 | if (is_old_name (def)) | |
1923 | register_new_update_single (def, def); | |
1924 | } | |
956623c1 MG |
1925 | |
1926 | return to_delete; | |
84d65814 DN |
1927 | } |
1928 | ||
1929 | ||
0bca51f0 DN |
1930 | /* Update every variable used in the statement pointed-to by SI. The |
1931 | statement is assumed to be in SSA form already. Names in | |
1932 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1933 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1934 | will be registered as a new definition for their corresponding name | |
956623c1 | 1935 | in OLD_SSA_NAMES. Returns whether STMT should be removed. */ |
0bca51f0 | 1936 | |
956623c1 | 1937 | static bool |
3a56edc7 | 1938 | rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi) |
0bca51f0 | 1939 | { |
0bca51f0 DN |
1940 | use_operand_p use_p; |
1941 | def_operand_p def_p; | |
1942 | ssa_op_iter iter; | |
1943 | ||
0bca51f0 | 1944 | /* Only update marked statements. */ |
726a989a | 1945 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
956623c1 | 1946 | return false; |
0bca51f0 DN |
1947 | |
1948 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1949 | { | |
1950 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 1951 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
1952 | } |
1953 | ||
1954 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1955 | symbol is marked for renaming. */ | |
726a989a | 1956 | if (rewrite_uses_p (stmt)) |
b5b8b0ac AO |
1957 | { |
1958 | if (is_gimple_debug (stmt)) | |
1959 | { | |
1960 | bool failed = false; | |
1961 | ||
1962 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1963 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
1964 | { | |
1965 | failed = true; | |
1966 | break; | |
1967 | } | |
1968 | ||
1969 | if (failed) | |
1970 | { | |
1971 | /* DOM sometimes threads jumps in such a way that a | |
1972 | debug stmt ends up referencing a SSA variable that no | |
1973 | longer dominates the debug stmt, but such that all | |
1974 | incoming definitions refer to the same definition in | |
1975 | an earlier dominator. We could try to recover that | |
1976 | definition somehow, but this will have to do for now. | |
1977 | ||
1978 | Introducing a default definition, which is what | |
1979 | maybe_replace_use() would do in such cases, may | |
1980 | modify code generation, for the otherwise-unused | |
1981 | default definition would never go away, modifying SSA | |
1982 | version numbers all over. */ | |
1983 | gimple_debug_bind_reset_value (stmt); | |
1984 | update_stmt (stmt); | |
1985 | } | |
1986 | } | |
1987 | else | |
1988 | { | |
1989 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
1990 | maybe_replace_use (use_p); | |
1991 | } | |
1992 | } | |
0bca51f0 DN |
1993 | |
1994 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
1995 | Also register definitions for names whose underlying symbol is | |
1996 | marked for renaming. */ | |
956623c1 | 1997 | bool to_delete = false; |
726a989a | 1998 | if (register_defs_p (stmt)) |
5006671f | 1999 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
956623c1 MG |
2000 | to_delete |= maybe_register_def (def_p, stmt, gsi); |
2001 | ||
2002 | return to_delete; | |
0bca51f0 DN |
2003 | } |
2004 | ||
2005 | ||
2006 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
2007 | every PHI node found, check if any of its arguments is in | |
2008 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
2009 | definition, replace it. */ | |
2010 | ||
2011 | static void | |
ccf5c864 | 2012 | rewrite_update_phi_arguments (basic_block bb) |
0bca51f0 DN |
2013 | { |
2014 | edge e; | |
2015 | edge_iterator ei; | |
2ce79879 | 2016 | unsigned i; |
0bca51f0 DN |
2017 | |
2018 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2019 | { | |
538dd0b7 DM |
2020 | gphi *phi; |
2021 | vec<gphi *> phis; | |
0bca51f0 | 2022 | |
2ce79879 ZD |
2023 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
2024 | continue; | |
b8698a0f | 2025 | |
9771b263 DN |
2026 | phis = phis_to_rewrite[e->dest->index]; |
2027 | FOR_EACH_VEC_ELT (phis, i, phi) | |
0bca51f0 | 2028 | { |
f5045c96 | 2029 | tree arg, lhs_sym, reaching_def = NULL; |
0bca51f0 DN |
2030 | use_operand_p arg_p; |
2031 | ||
4ad14919 | 2032 | gcc_checking_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
2033 | |
2034 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2035 | arg = USE_FROM_PTR (arg_p); | |
2036 | ||
2037 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2038 | continue; | |
2039 | ||
726a989a | 2040 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 2041 | |
0bca51f0 DN |
2042 | if (arg == NULL_TREE) |
2043 | { | |
2044 | /* When updating a PHI node for a recently introduced | |
2045 | symbol we may find NULL arguments. That's why we | |
2046 | take the symbol from the LHS of the PHI node. */ | |
f5045c96 AM |
2047 | reaching_def = get_reaching_def (lhs_sym); |
2048 | ||
0bca51f0 DN |
2049 | } |
2050 | else | |
2051 | { | |
2052 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2053 | ||
13714310 | 2054 | if (marked_for_renaming (sym)) |
f5045c96 | 2055 | reaching_def = get_reaching_def (sym); |
0bca51f0 | 2056 | else if (is_old_name (arg)) |
f5045c96 AM |
2057 | reaching_def = get_reaching_def (arg); |
2058 | } | |
2059 | ||
2060 | /* Update the argument if there is a reaching def. */ | |
2061 | if (reaching_def) | |
2062 | { | |
f5045c96 AM |
2063 | source_location locus; |
2064 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2065 | ||
2066 | SET_USE (arg_p, reaching_def); | |
f5045c96 | 2067 | |
ffc5b2bb RB |
2068 | /* Virtual operands do not need a location. */ |
2069 | if (virtual_operand_p (reaching_def)) | |
2070 | locus = UNKNOWN_LOCATION; | |
f5045c96 | 2071 | else |
ffc5b2bb RB |
2072 | { |
2073 | gimple stmt = SSA_NAME_DEF_STMT (reaching_def); | |
538dd0b7 | 2074 | gphi *other_phi = dyn_cast <gphi *> (stmt); |
ffc5b2bb RB |
2075 | |
2076 | /* Single element PHI nodes behave like copies, so get the | |
2077 | location from the phi argument. */ | |
538dd0b7 DM |
2078 | if (other_phi |
2079 | && gimple_phi_num_args (other_phi) == 1) | |
2080 | locus = gimple_phi_arg_location (other_phi, 0); | |
ffc5b2bb RB |
2081 | else |
2082 | locus = gimple_location (stmt); | |
2083 | } | |
f5045c96 AM |
2084 | |
2085 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
0bca51f0 DN |
2086 | } |
2087 | ||
f5045c96 | 2088 | |
0bca51f0 DN |
2089 | if (e->flags & EDGE_ABNORMAL) |
2090 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2091 | } | |
2092 | } | |
2093 | } | |
2094 | ||
4d9192b5 TS |
2095 | class rewrite_update_dom_walker : public dom_walker |
2096 | { | |
2097 | public: | |
2098 | rewrite_update_dom_walker (cdi_direction direction) : dom_walker (direction) {} | |
2099 | ||
2100 | virtual void before_dom_children (basic_block); | |
2101 | virtual void after_dom_children (basic_block); | |
2102 | }; | |
0bca51f0 | 2103 | |
ccf5c864 PB |
2104 | /* Initialization of block data structures for the incremental SSA |
2105 | update pass. Create a block local stack of reaching definitions | |
2106 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2107 | new definitions for every PHI node in the block. */ | |
2108 | ||
4d9192b5 TS |
2109 | void |
2110 | rewrite_update_dom_walker::before_dom_children (basic_block bb) | |
ccf5c864 | 2111 | { |
ccf5c864 | 2112 | bool is_abnormal_phi; |
ccf5c864 PB |
2113 | |
2114 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
427f99e2 | 2115 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
ccf5c864 PB |
2116 | bb->index); |
2117 | ||
2118 | /* Mark the unwind point for this block. */ | |
9771b263 | 2119 | block_defs_stack.safe_push (NULL_TREE); |
ccf5c864 PB |
2120 | |
2121 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
2122 | return; | |
2123 | ||
2124 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2125 | edge. */ | |
31ff2426 | 2126 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
ccf5c864 PB |
2127 | |
2128 | /* If any of the PHI nodes is a replacement for a name in | |
2129 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2130 | register it as a new definition for its corresponding name. Also | |
2131 | register definitions for names whose underlying symbols are | |
2132 | marked for renaming. */ | |
538dd0b7 DM |
2133 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
2134 | gsi_next (&gsi)) | |
ccf5c864 PB |
2135 | { |
2136 | tree lhs, lhs_sym; | |
538dd0b7 | 2137 | gphi *phi = gsi.phi (); |
ccf5c864 PB |
2138 | |
2139 | if (!register_defs_p (phi)) | |
2140 | continue; | |
b8698a0f | 2141 | |
ccf5c864 PB |
2142 | lhs = gimple_phi_result (phi); |
2143 | lhs_sym = SSA_NAME_VAR (lhs); | |
2144 | ||
13714310 | 2145 | if (marked_for_renaming (lhs_sym)) |
ccf5c864 PB |
2146 | register_new_update_single (lhs, lhs_sym); |
2147 | else | |
2148 | { | |
2149 | ||
2150 | /* If LHS is a new name, register a new definition for all | |
2151 | the names replaced by LHS. */ | |
2152 | if (is_new_name (lhs)) | |
2153 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
b8698a0f | 2154 | |
ccf5c864 PB |
2155 | /* If LHS is an OLD name, register it as a new definition |
2156 | for itself. */ | |
2157 | if (is_old_name (lhs)) | |
2158 | register_new_update_single (lhs, lhs); | |
2159 | } | |
2160 | ||
2161 | if (is_abnormal_phi) | |
2162 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2163 | } | |
2164 | ||
2165 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
d7c028c0 | 2166 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
3a56edc7 | 2167 | { |
4ad14919 | 2168 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
538dd0b7 | 2169 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) |
956623c1 MG |
2170 | if (rewrite_update_stmt (gsi_stmt (gsi), gsi)) |
2171 | gsi_remove (&gsi, true); | |
2172 | else | |
2173 | gsi_next (&gsi); | |
3a56edc7 | 2174 | } |
ccf5c864 PB |
2175 | |
2176 | /* Step 3. Update PHI nodes. */ | |
2177 | rewrite_update_phi_arguments (bb); | |
2178 | } | |
2179 | ||
2180 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2181 | the current reaching definition of every name re-written in BB to | |
2182 | the original reaching definition before visiting BB. This | |
2183 | unwinding must be done in the opposite order to what is done in | |
2184 | register_new_update_set. */ | |
2185 | ||
4d9192b5 TS |
2186 | void |
2187 | rewrite_update_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
ccf5c864 | 2188 | { |
9771b263 | 2189 | while (block_defs_stack.length () > 0) |
ccf5c864 | 2190 | { |
9771b263 | 2191 | tree var = block_defs_stack.pop (); |
ccf5c864 | 2192 | tree saved_def; |
b8698a0f | 2193 | |
ccf5c864 PB |
2194 | /* NULL indicates the unwind stop point for this block (see |
2195 | rewrite_update_enter_block). */ | |
2196 | if (var == NULL) | |
2197 | return; | |
2198 | ||
9771b263 | 2199 | saved_def = block_defs_stack.pop (); |
8812aab1 | 2200 | get_common_info (var)->current_def = saved_def; |
ccf5c864 PB |
2201 | } |
2202 | } | |
2203 | ||
2204 | ||
0bca51f0 | 2205 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
b8698a0f | 2206 | form. |
0bca51f0 DN |
2207 | |
2208 | ENTRY indicates the block where to start. Every block dominated by | |
2209 | ENTRY will be rewritten. | |
2210 | ||
2211 | WHAT indicates what actions will be taken by the renamer (see enum | |
2212 | rewrite_mode). | |
2213 | ||
2214 | BLOCKS are the set of interesting blocks for the dominator walker | |
2215 | to process. If this set is NULL, then all the nodes dominated | |
2216 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2217 | are not present in BLOCKS are ignored. */ | |
2218 | ||
2219 | static void | |
ccf5c864 | 2220 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
0bca51f0 | 2221 | { |
0bca51f0 DN |
2222 | /* Rewrite all the basic blocks in the program. */ |
2223 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2224 | ||
4d9192b5 | 2225 | block_defs_stack.create (10); |
0bca51f0 | 2226 | |
4d9192b5 TS |
2227 | /* Recursively walk the dominator tree rewriting each statement in |
2228 | each basic block. */ | |
0bca51f0 | 2229 | if (what == REWRITE_ALL) |
4d9192b5 | 2230 | rewrite_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 | 2231 | else if (what == REWRITE_UPDATE) |
4d9192b5 | 2232 | rewrite_update_dom_walker (CDI_DOMINATORS).walk (entry); |
0bca51f0 DN |
2233 | else |
2234 | gcc_unreachable (); | |
2235 | ||
0bca51f0 DN |
2236 | /* Debugging dumps. */ |
2237 | if (dump_file && (dump_flags & TDF_STATS)) | |
2238 | { | |
2239 | dump_dfa_stats (dump_file); | |
c203e8a7 | 2240 | if (var_infos) |
0bca51f0 DN |
2241 | dump_tree_ssa_stats (dump_file); |
2242 | } | |
b8698a0f | 2243 | |
9771b263 | 2244 | block_defs_stack.release (); |
0bca51f0 DN |
2245 | |
2246 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2247 | } | |
2248 | ||
4d9192b5 | 2249 | class mark_def_dom_walker : public dom_walker |
7256233c | 2250 | { |
4d9192b5 TS |
2251 | public: |
2252 | mark_def_dom_walker (cdi_direction direction); | |
2253 | ~mark_def_dom_walker (); | |
5f240ec4 | 2254 | |
4d9192b5 | 2255 | virtual void before_dom_children (basic_block); |
5f240ec4 | 2256 | |
4d9192b5 | 2257 | private: |
7256233c DN |
2258 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2259 | large enough to accommodate all the variables referenced in the | |
2260 | function, not just the ones we are renaming. */ | |
65d3284b | 2261 | bitmap m_kills; |
4d9192b5 | 2262 | }; |
6de9cd9a | 2263 | |
4d9192b5 | 2264 | mark_def_dom_walker::mark_def_dom_walker (cdi_direction direction) |
65d3284b | 2265 | : dom_walker (direction), m_kills (BITMAP_ALLOC (NULL)) |
4d9192b5 TS |
2266 | { |
2267 | } | |
7256233c | 2268 | |
4d9192b5 TS |
2269 | mark_def_dom_walker::~mark_def_dom_walker () |
2270 | { | |
65d3284b | 2271 | BITMAP_FREE (m_kills); |
4d9192b5 | 2272 | } |
7256233c | 2273 | |
4d9192b5 TS |
2274 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2275 | at the start of each block, and call mark_def_sites for each statement. */ | |
7256233c | 2276 | |
4d9192b5 TS |
2277 | void |
2278 | mark_def_dom_walker::before_dom_children (basic_block bb) | |
2279 | { | |
2280 | gimple_stmt_iterator gsi; | |
7256233c | 2281 | |
65d3284b | 2282 | bitmap_clear (m_kills); |
4d9192b5 | 2283 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
65d3284b | 2284 | mark_def_sites (bb, gsi_stmt (gsi), m_kills); |
6de9cd9a DN |
2285 | } |
2286 | ||
38635499 DN |
2287 | /* Initialize internal data needed during renaming. */ |
2288 | ||
2289 | static void | |
2290 | init_ssa_renamer (void) | |
2291 | { | |
38635499 DN |
2292 | cfun->gimple_df->in_ssa_p = false; |
2293 | ||
2294 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
c203e8a7 TS |
2295 | gcc_assert (!var_infos); |
2296 | var_infos = new hash_table<var_info_hasher> | |
2297 | (vec_safe_length (cfun->local_decls)); | |
38635499 | 2298 | |
b4e209fd | 2299 | bitmap_obstack_initialize (&update_ssa_obstack); |
38635499 DN |
2300 | } |
2301 | ||
2302 | ||
2303 | /* Deallocate internal data structures used by the renamer. */ | |
2304 | ||
2305 | static void | |
2306 | fini_ssa_renamer (void) | |
2307 | { | |
c203e8a7 TS |
2308 | delete var_infos; |
2309 | var_infos = NULL; | |
38635499 | 2310 | |
b4e209fd RG |
2311 | bitmap_obstack_release (&update_ssa_obstack); |
2312 | ||
13714310 RG |
2313 | cfun->gimple_df->ssa_renaming_needed = 0; |
2314 | cfun->gimple_df->rename_vops = 0; | |
38635499 DN |
2315 | cfun->gimple_df->in_ssa_p = true; |
2316 | } | |
2317 | ||
7256233c | 2318 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2319 | proceeds in four main phases: |
6de9cd9a | 2320 | |
0bca51f0 DN |
2321 | 1- Compute dominance frontier and immediate dominators, needed to |
2322 | insert PHI nodes and rename the function in dominator tree | |
2323 | order. | |
6de9cd9a | 2324 | |
4d9192b5 | 2325 | 2- Find and mark all the blocks that define variables. |
6de9cd9a | 2326 | |
0bca51f0 | 2327 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2328 | |
0bca51f0 | 2329 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2330 | |
77bfa778 | 2331 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2332 | (walk_dominator_tree). */ |
7256233c | 2333 | |
be55bfe6 TS |
2334 | namespace { |
2335 | ||
2336 | const pass_data pass_data_build_ssa = | |
2337 | { | |
2338 | GIMPLE_PASS, /* type */ | |
2339 | "ssa", /* name */ | |
2340 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
2341 | TV_TREE_SSA_OTHER, /* tv_id */ |
2342 | PROP_cfg, /* properties_required */ | |
2343 | PROP_ssa, /* properties_provided */ | |
2344 | 0, /* properties_destroyed */ | |
2345 | 0, /* todo_flags_start */ | |
3bea341f | 2346 | TODO_remove_unused_locals, /* todo_flags_finish */ |
be55bfe6 TS |
2347 | }; |
2348 | ||
2349 | class pass_build_ssa : public gimple_opt_pass | |
2350 | { | |
2351 | public: | |
2352 | pass_build_ssa (gcc::context *ctxt) | |
2353 | : gimple_opt_pass (pass_data_build_ssa, ctxt) | |
2354 | {} | |
2355 | ||
2356 | /* opt_pass methods: */ | |
2357 | virtual bool gate (function *fun) | |
2358 | { | |
2359 | /* Do nothing for funcions that was produced already in SSA form. */ | |
2360 | return !(fun->curr_properties & PROP_ssa); | |
2361 | } | |
2362 | ||
2363 | virtual unsigned int execute (function *); | |
2364 | ||
2365 | }; // class pass_build_ssa | |
2366 | ||
2367 | unsigned int | |
2368 | pass_build_ssa::execute (function *fun) | |
6de9cd9a | 2369 | { |
0fc555fb | 2370 | bitmap_head *dfs; |
7256233c | 2371 | basic_block bb; |
70b5e7dc | 2372 | unsigned i; |
b8698a0f | 2373 | |
0bca51f0 | 2374 | /* Initialize operand data structures. */ |
be55bfe6 | 2375 | init_ssa_operands (fun); |
6de9cd9a | 2376 | |
38635499 DN |
2377 | /* Initialize internal data needed by the renamer. */ |
2378 | init_ssa_renamer (); | |
2379 | ||
0bca51f0 DN |
2380 | /* Initialize the set of interesting blocks. The callback |
2381 | mark_def_sites will add to this set those blocks that the renamer | |
2382 | should process. */ | |
be55bfe6 | 2383 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (fun)); |
f61e445a | 2384 | bitmap_clear (interesting_blocks); |
6de9cd9a | 2385 | |
af5d3a18 | 2386 | /* Initialize dominance frontier. */ |
be55bfe6 TS |
2387 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (fun)); |
2388 | FOR_EACH_BB_FN (bb, fun) | |
0fc555fb | 2389 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
6de9cd9a | 2390 | |
0bca51f0 DN |
2391 | /* 1- Compute dominance frontiers. */ |
2392 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2393 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2394 | |
0bca51f0 | 2395 | /* 2- Find and mark definition sites. */ |
be55bfe6 | 2396 | mark_def_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr); |
0bca51f0 DN |
2397 | |
2398 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2399 | insert_phi_nodes (dfs); |
6de9cd9a | 2400 | |
0bca51f0 | 2401 | /* 4- Rename all the blocks. */ |
be55bfe6 | 2402 | rewrite_blocks (ENTRY_BLOCK_PTR_FOR_FN (fun), REWRITE_ALL); |
6de9cd9a | 2403 | |
7256233c | 2404 | /* Free allocated memory. */ |
be55bfe6 | 2405 | FOR_EACH_BB_FN (bb, fun) |
0fc555fb | 2406 | bitmap_clear (&dfs[bb->index]); |
7256233c | 2407 | free (dfs); |
6de9cd9a | 2408 | |
b5dcb2b9 JL |
2409 | sbitmap_free (interesting_blocks); |
2410 | ||
38635499 DN |
2411 | fini_ssa_renamer (); |
2412 | ||
70b5e7dc RG |
2413 | /* Try to get rid of all gimplifier generated temporaries by making |
2414 | its SSA names anonymous. This way we can garbage collect them | |
2415 | all after removing unused locals which we do in our TODO. */ | |
2416 | for (i = 1; i < num_ssa_names; ++i) | |
2417 | { | |
2418 | tree decl, name = ssa_name (i); | |
2419 | if (!name | |
2420 | || SSA_NAME_IS_DEFAULT_DEF (name)) | |
2421 | continue; | |
2422 | decl = SSA_NAME_VAR (name); | |
2423 | if (decl | |
2424 | && TREE_CODE (decl) == VAR_DECL | |
2425 | && !VAR_DECL_IS_VIRTUAL_OPERAND (decl) | |
74fc8b8a RB |
2426 | && DECL_IGNORED_P (decl)) |
2427 | SET_SSA_NAME_VAR_OR_IDENTIFIER (name, DECL_NAME (decl)); | |
70b5e7dc RG |
2428 | } |
2429 | ||
c2924966 | 2430 | return 0; |
6de9cd9a DN |
2431 | } |
2432 | ||
27a4cd48 DM |
2433 | } // anon namespace |
2434 | ||
2435 | gimple_opt_pass * | |
2436 | make_pass_build_ssa (gcc::context *ctxt) | |
2437 | { | |
2438 | return new pass_build_ssa (ctxt); | |
2439 | } | |
2440 | ||
6de9cd9a | 2441 | |
0bca51f0 DN |
2442 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2443 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2444 | |
0bca51f0 | 2445 | static void |
726a989a | 2446 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
6de9cd9a | 2447 | { |
4ad14919 | 2448 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2449 | set_register_defs (stmt, true); |
0bca51f0 DN |
2450 | |
2451 | if (insert_phi_p) | |
2452 | { | |
726a989a | 2453 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2454 | |
0bca51f0 DN |
2455 | set_def_block (var, bb, is_phi_p); |
2456 | ||
2457 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2458 | site for both itself and all the old names replaced by it. */ | |
2459 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2460 | { | |
2461 | bitmap_iterator bi; | |
2462 | unsigned i; | |
2463 | bitmap set = names_replaced_by (var); | |
2464 | if (set) | |
2465 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2466 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2467 | } | |
2468 | } | |
2469 | } | |
2470 | ||
2471 | ||
2472 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2473 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2474 | nodes. */ |
0bca51f0 DN |
2475 | |
2476 | static inline void | |
726a989a | 2477 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
0bca51f0 | 2478 | { |
726a989a | 2479 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2480 | |
95dd3097 ZD |
2481 | mark_block_for_update (def_bb); |
2482 | mark_block_for_update (bb); | |
2483 | ||
726a989a | 2484 | if (gimple_code (stmt) == GIMPLE_PHI) |
538dd0b7 | 2485 | mark_phi_for_rewrite (def_bb, as_a <gphi *> (stmt)); |
2ce79879 | 2486 | else |
b5b8b0ac AO |
2487 | { |
2488 | set_rewrite_uses (stmt, true); | |
2489 | ||
2490 | if (is_gimple_debug (stmt)) | |
2491 | return; | |
2492 | } | |
0bca51f0 DN |
2493 | |
2494 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2495 | to BB. Note that we cannot just use the block holding VAR's | |
2496 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2497 | it will have several definitions (itself and all the names that | |
2498 | replace it). */ | |
2499 | if (insert_phi_p) | |
2500 | { | |
8812aab1 | 2501 | struct def_blocks_d *db_p = get_def_blocks_for (get_common_info (var)); |
0bca51f0 DN |
2502 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2503 | set_livein_block (var, bb); | |
2504 | } | |
2505 | } | |
2506 | ||
2507 | ||
0bca51f0 | 2508 | /* Do a dominator walk starting at BB processing statements that |
13714310 | 2509 | reference symbols in SSA operands. This is very similar to |
84d65814 | 2510 | mark_def_sites, but the scan handles statements whose operands may |
95dd3097 | 2511 | already be SSA names. |
0bca51f0 | 2512 | |
84d65814 DN |
2513 | If INSERT_PHI_P is true, mark those uses as live in the |
2514 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2515 | algorithm to make PHI pruning decisions. |
2516 | ||
2517 | FIXME. Most of this would be unnecessary if we could associate a | |
2518 | symbol to all the SSA names that reference it. But that | |
2519 | sounds like it would be expensive to maintain. Still, it | |
2520 | would be interesting to see if it makes better sense to do | |
2521 | that. */ | |
0bca51f0 DN |
2522 | |
2523 | static void | |
95dd3097 | 2524 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2525 | { |
2526 | basic_block son; | |
f074ff6c ZD |
2527 | edge e; |
2528 | edge_iterator ei; | |
0bca51f0 | 2529 | |
95dd3097 ZD |
2530 | mark_block_for_update (bb); |
2531 | ||
0bca51f0 | 2532 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2533 | the symbols that we are interested in. */ |
538dd0b7 DM |
2534 | for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); |
2535 | gsi_next (&si)) | |
0bca51f0 | 2536 | { |
538dd0b7 | 2537 | gphi *phi = si.phi (); |
726a989a | 2538 | tree lhs_sym, lhs = gimple_phi_result (phi); |
0bca51f0 | 2539 | |
13714310 | 2540 | if (TREE_CODE (lhs) == SSA_NAME |
a471762f RG |
2541 | && (! virtual_operand_p (lhs) |
2542 | || ! cfun->gimple_df->rename_vops)) | |
f074ff6c | 2543 | continue; |
726a989a | 2544 | |
a471762f | 2545 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
13714310 | 2546 | mark_for_renaming (lhs_sym); |
f074ff6c ZD |
2547 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2548 | ||
2549 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2550 | to process the arguments of the phi nodes of the successor edges of | |
2551 | BB at the end of prepare_block_for_update, however, that turns out | |
2552 | to be significantly more expensive. Doing it here is conservatively | |
2553 | correct -- it may only cause us to believe a value to be live in a | |
2554 | block that also contains its definition, and thus insert a few more | |
2555 | phi nodes for it. */ | |
2556 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2557 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2558 | } |
2559 | ||
2560 | /* Process the statements. */ | |
538dd0b7 DM |
2561 | for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); |
2562 | gsi_next (&si)) | |
0bca51f0 | 2563 | { |
726a989a | 2564 | gimple stmt; |
0bca51f0 DN |
2565 | ssa_op_iter i; |
2566 | use_operand_p use_p; | |
2567 | def_operand_p def_p; | |
b8698a0f | 2568 | |
726a989a | 2569 | stmt = gsi_stmt (si); |
0bca51f0 | 2570 | |
13714310 RG |
2571 | if (cfun->gimple_df->rename_vops |
2572 | && gimple_vuse (stmt)) | |
0bca51f0 | 2573 | { |
13714310 | 2574 | tree use = gimple_vuse (stmt); |
0bca51f0 | 2575 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
13714310 RG |
2576 | mark_for_renaming (sym); |
2577 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2578 | } |
2579 | ||
13714310 | 2580 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
0bca51f0 | 2581 | { |
13714310 RG |
2582 | tree use = USE_FROM_PTR (use_p); |
2583 | if (!DECL_P (use)) | |
2584 | continue; | |
2585 | mark_for_renaming (use); | |
2586 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2587 | } | |
2588 | ||
2589 | if (cfun->gimple_df->rename_vops | |
2590 | && gimple_vdef (stmt)) | |
2591 | { | |
2592 | tree def = gimple_vdef (stmt); | |
0bca51f0 | 2593 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
13714310 RG |
2594 | mark_for_renaming (sym); |
2595 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2596 | } | |
2597 | ||
2598 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2599 | { | |
2600 | tree def = DEF_FROM_PTR (def_p); | |
2601 | if (!DECL_P (def)) | |
2602 | continue; | |
2603 | mark_for_renaming (def); | |
2604 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2605 | } |
2606 | } | |
2607 | ||
2608 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2609 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2610 | son; |
2611 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2612 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2613 | } |
2614 | ||
2615 | ||
2616 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2617 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2618 | prepare_names_to_update. */ | |
2619 | ||
2620 | static void | |
95dd3097 | 2621 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2622 | { |
2623 | use_operand_p use_p; | |
2624 | imm_use_iterator iter; | |
2625 | ||
2626 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2627 | { | |
726a989a RB |
2628 | gimple stmt = USE_STMT (use_p); |
2629 | basic_block bb = gimple_bb (stmt); | |
84d65814 | 2630 | |
726a989a | 2631 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2632 | { |
f074ff6c | 2633 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
538dd0b7 | 2634 | edge e = gimple_phi_arg_edge (as_a <gphi *> (stmt), ix); |
f074ff6c | 2635 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2636 | } |
2637 | else | |
2638 | { | |
2639 | /* For regular statements, mark this as an interesting use | |
2640 | for NAME. */ | |
95dd3097 | 2641 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2642 | } |
2643 | } | |
0bca51f0 DN |
2644 | } |
2645 | ||
2646 | ||
84d65814 DN |
2647 | /* Helper for prepare_names_to_update. Mark the definition site for |
2648 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2649 | prepare_names_to_update. */ | |
0bca51f0 DN |
2650 | |
2651 | static void | |
95dd3097 | 2652 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2653 | { |
726a989a | 2654 | gimple stmt; |
0bca51f0 DN |
2655 | basic_block bb; |
2656 | ||
4ad14919 RG |
2657 | gcc_checking_assert (names_to_release == NULL |
2658 | || !bitmap_bit_p (names_to_release, | |
2659 | SSA_NAME_VERSION (name))); | |
0bca51f0 DN |
2660 | |
2661 | stmt = SSA_NAME_DEF_STMT (name); | |
726a989a | 2662 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2663 | if (bb) |
2664 | { | |
8b1c6fd7 | 2665 | gcc_checking_assert (bb->index < last_basic_block_for_fn (cfun)); |
95dd3097 ZD |
2666 | mark_block_for_update (bb); |
2667 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2668 | } |
2669 | } | |
2670 | ||
2671 | ||
84d65814 | 2672 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2673 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2674 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2675 | |
2676 | static void | |
95dd3097 | 2677 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2678 | { |
dfea6c85 | 2679 | unsigned i = 0; |
0bca51f0 | 2680 | bitmap_iterator bi; |
b6e7e9af | 2681 | sbitmap_iterator sbi; |
0bca51f0 DN |
2682 | |
2683 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2684 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2685 | defining basic block (which most likely doesn't exist). Notice | |
2686 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2687 | want to replace existing instances. */ | |
2688 | if (names_to_release) | |
2689 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
d7c028c0 | 2690 | bitmap_clear_bit (new_ssa_names, i); |
0bca51f0 | 2691 | |
84d65814 DN |
2692 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2693 | names may be considered to be live-in on blocks that contain | |
2694 | definitions for their replacements. */ | |
d4ac4ce2 | 2695 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2696 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2697 | |
0bca51f0 DN |
2698 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2699 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
d4ac4ce2 | 2700 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2701 | { |
2702 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2703 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2704 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2705 | } |
0bca51f0 DN |
2706 | } |
2707 | ||
2708 | ||
2709 | /* Dump all the names replaced by NAME to FILE. */ | |
2710 | ||
2711 | void | |
2712 | dump_names_replaced_by (FILE *file, tree name) | |
2713 | { | |
2714 | unsigned i; | |
2715 | bitmap old_set; | |
2716 | bitmap_iterator bi; | |
2717 | ||
2718 | print_generic_expr (file, name, 0); | |
2719 | fprintf (file, " -> { "); | |
2720 | ||
2721 | old_set = names_replaced_by (name); | |
2722 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2723 | { | |
2724 | print_generic_expr (file, ssa_name (i), 0); | |
2725 | fprintf (file, " "); | |
2726 | } | |
2727 | ||
2728 | fprintf (file, "}\n"); | |
2729 | } | |
2730 | ||
2731 | ||
2732 | /* Dump all the names replaced by NAME to stderr. */ | |
2733 | ||
24e47c76 | 2734 | DEBUG_FUNCTION void |
0bca51f0 DN |
2735 | debug_names_replaced_by (tree name) |
2736 | { | |
2737 | dump_names_replaced_by (stderr, name); | |
2738 | } | |
2739 | ||
2740 | ||
84d65814 | 2741 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2742 | |
2743 | void | |
84d65814 | 2744 | dump_update_ssa (FILE *file) |
0bca51f0 | 2745 | { |
dfea6c85 | 2746 | unsigned i = 0; |
0bca51f0 DN |
2747 | bitmap_iterator bi; |
2748 | ||
5006671f | 2749 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
2750 | return; |
2751 | ||
f61e445a | 2752 | if (new_ssa_names && bitmap_first_set_bit (new_ssa_names) >= 0) |
0bca51f0 | 2753 | { |
b6e7e9af KH |
2754 | sbitmap_iterator sbi; |
2755 | ||
0bca51f0 DN |
2756 | fprintf (file, "\nSSA replacement table\n"); |
2757 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2758 | "O_1, ..., O_j\n\n"); | |
2759 | ||
d4ac4ce2 | 2760 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
b6e7e9af | 2761 | dump_names_replaced_by (file, ssa_name (i)); |
0bca51f0 DN |
2762 | } |
2763 | ||
13714310 | 2764 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
0bca51f0 | 2765 | { |
427f99e2 | 2766 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
13714310 | 2767 | dump_decl_set (file, symbols_to_rename_set); |
5006671f | 2768 | fprintf (file, "\n"); |
0bca51f0 DN |
2769 | } |
2770 | ||
0bca51f0 DN |
2771 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2772 | { | |
427f99e2 | 2773 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
0bca51f0 DN |
2774 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2775 | { | |
2776 | print_generic_expr (file, ssa_name (i), 0); | |
2777 | fprintf (file, " "); | |
2778 | } | |
427f99e2 | 2779 | fprintf (file, "\n"); |
0bca51f0 | 2780 | } |
0bca51f0 DN |
2781 | } |
2782 | ||
2783 | ||
84d65814 | 2784 | /* Dump SSA update information to stderr. */ |
0bca51f0 | 2785 | |
24e47c76 | 2786 | DEBUG_FUNCTION void |
84d65814 | 2787 | debug_update_ssa (void) |
0bca51f0 | 2788 | { |
84d65814 | 2789 | dump_update_ssa (stderr); |
0bca51f0 DN |
2790 | } |
2791 | ||
2792 | ||
2793 | /* Initialize data structures used for incremental SSA updates. */ | |
2794 | ||
2795 | static void | |
5006671f | 2796 | init_update_ssa (struct function *fn) |
0bca51f0 | 2797 | { |
84d65814 | 2798 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2799 | add_new_name_mapping are typically done after creating new SSA |
2800 | names, so we'll need to reallocate these arrays. */ | |
2801 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2802 | bitmap_clear (old_ssa_names); |
0bca51f0 DN |
2803 | |
2804 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
f61e445a | 2805 | bitmap_clear (new_ssa_names); |
0bca51f0 | 2806 | |
891f2df6 RG |
2807 | bitmap_obstack_initialize (&update_ssa_obstack); |
2808 | ||
0bca51f0 | 2809 | names_to_release = NULL; |
5006671f | 2810 | update_ssa_initialized_fn = fn; |
0bca51f0 DN |
2811 | } |
2812 | ||
2813 | ||
2814 | /* Deallocate data structures used for incremental SSA updates. */ | |
2815 | ||
84d65814 | 2816 | void |
0bca51f0 DN |
2817 | delete_update_ssa (void) |
2818 | { | |
2819 | unsigned i; | |
2820 | bitmap_iterator bi; | |
2821 | ||
2822 | sbitmap_free (old_ssa_names); | |
2823 | old_ssa_names = NULL; | |
2824 | ||
2825 | sbitmap_free (new_ssa_names); | |
2826 | new_ssa_names = NULL; | |
2827 | ||
13714310 RG |
2828 | BITMAP_FREE (symbols_to_rename_set); |
2829 | symbols_to_rename_set = NULL; | |
9771b263 | 2830 | symbols_to_rename.release (); |
0bca51f0 DN |
2831 | |
2832 | if (names_to_release) | |
2833 | { | |
2834 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2835 | release_ssa_name (ssa_name (i)); | |
2836 | BITMAP_FREE (names_to_release); | |
2837 | } | |
2838 | ||
95dd3097 | 2839 | clear_ssa_name_info (); |
38635499 DN |
2840 | |
2841 | fini_ssa_renamer (); | |
2842 | ||
2843 | if (blocks_with_phis_to_rewrite) | |
2844 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2845 | { | |
538dd0b7 | 2846 | vec<gphi *> phis = phis_to_rewrite[i]; |
9771b263 DN |
2847 | phis.release (); |
2848 | phis_to_rewrite[i].create (0); | |
38635499 DN |
2849 | } |
2850 | ||
2851 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2852 | BITMAP_FREE (blocks_to_update); | |
891f2df6 | 2853 | |
5006671f | 2854 | update_ssa_initialized_fn = NULL; |
0bca51f0 DN |
2855 | } |
2856 | ||
2857 | ||
2858 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
45db3141 RG |
2859 | operand pointed to by DEF_P with the newly created name. If DEF_P |
2860 | is NULL then STMT should be a GIMPLE assignment. | |
2861 | Return the new name and register the replacement mapping <NEW, OLD> in | |
0bca51f0 DN |
2862 | update_ssa's tables. */ |
2863 | ||
2864 | tree | |
726a989a | 2865 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
0bca51f0 | 2866 | { |
45db3141 | 2867 | tree new_name; |
0bca51f0 | 2868 | |
45db3141 RG |
2869 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
2870 | ||
2871 | if (!update_ssa_initialized_fn) | |
2872 | init_update_ssa (cfun); | |
2873 | ||
2874 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2875 | ||
2876 | new_name = duplicate_ssa_name (old_name, stmt); | |
2877 | if (def) | |
2878 | SET_DEF (def, new_name); | |
2879 | else | |
2880 | gimple_assign_set_lhs (stmt, new_name); | |
0bca51f0 | 2881 | |
726a989a | 2882 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 | 2883 | { |
726a989a | 2884 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2885 | |
2886 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
31ff2426 | 2887 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
0bca51f0 DN |
2888 | } |
2889 | ||
45db3141 | 2890 | add_new_name_mapping (new_name, old_name); |
0bca51f0 DN |
2891 | |
2892 | /* For the benefit of passes that will be updating the SSA form on | |
2893 | their own, set the current reaching definition of OLD_NAME to be | |
2894 | NEW_NAME. */ | |
8812aab1 | 2895 | get_ssa_name_ann (old_name)->info.current_def = new_name; |
0bca51f0 | 2896 | |
45db3141 | 2897 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
0bca51f0 | 2898 | |
45db3141 | 2899 | return new_name; |
0bca51f0 DN |
2900 | } |
2901 | ||
2902 | ||
525174a2 | 2903 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
0bca51f0 DN |
2904 | |
2905 | void | |
525174a2 | 2906 | mark_virtual_operands_for_renaming (struct function *fn) |
0bca51f0 | 2907 | { |
525174a2 RG |
2908 | fn->gimple_df->ssa_renaming_needed = 1; |
2909 | fn->gimple_df->rename_vops = 1; | |
0bca51f0 DN |
2910 | } |
2911 | ||
3d9c733e AM |
2912 | /* Replace all uses of NAME by underlying variable and mark it |
2913 | for renaming. This assumes the defining statement of NAME is | |
2914 | going to be removed. */ | |
2915 | ||
2916 | void | |
2917 | mark_virtual_operand_for_renaming (tree name) | |
2918 | { | |
2919 | tree name_var = SSA_NAME_VAR (name); | |
2920 | bool used = false; | |
2921 | imm_use_iterator iter; | |
2922 | use_operand_p use_p; | |
2923 | gimple stmt; | |
2924 | ||
2925 | gcc_assert (VAR_DECL_IS_VIRTUAL_OPERAND (name_var)); | |
2926 | FOR_EACH_IMM_USE_STMT (stmt, iter, name) | |
2927 | { | |
2928 | FOR_EACH_IMM_USE_ON_STMT (use_p, iter) | |
2929 | SET_USE (use_p, name_var); | |
2930 | used = true; | |
2931 | } | |
2932 | if (used) | |
2933 | mark_virtual_operands_for_renaming (cfun); | |
2934 | } | |
2935 | ||
2936 | /* Replace all uses of the virtual PHI result by its underlying variable | |
2937 | and mark it for renaming. This assumes the PHI node is going to be | |
2938 | removed. */ | |
2939 | ||
2940 | void | |
538dd0b7 | 2941 | mark_virtual_phi_result_for_renaming (gphi *phi) |
3d9c733e AM |
2942 | { |
2943 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2944 | { | |
2945 | fprintf (dump_file, "Marking result for renaming : "); | |
2946 | print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
2947 | fprintf (dump_file, "\n"); | |
2948 | } | |
2949 | ||
2950 | mark_virtual_operand_for_renaming (gimple_phi_result (phi)); | |
2951 | } | |
0bca51f0 | 2952 | |
5006671f RG |
2953 | /* Return true if there is any work to be done by update_ssa |
2954 | for function FN. */ | |
0bca51f0 DN |
2955 | |
2956 | bool | |
5006671f | 2957 | need_ssa_update_p (struct function *fn) |
0bca51f0 | 2958 | { |
5006671f RG |
2959 | gcc_assert (fn != NULL); |
2960 | return (update_ssa_initialized_fn == fn | |
13714310 | 2961 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
0bca51f0 DN |
2962 | } |
2963 | ||
0bca51f0 DN |
2964 | /* Return true if name N has been registered in the replacement table. */ |
2965 | ||
2966 | bool | |
726a989a | 2967 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 | 2968 | { |
5006671f | 2969 | if (!update_ssa_initialized_fn) |
0bca51f0 DN |
2970 | return false; |
2971 | ||
5006671f RG |
2972 | gcc_assert (update_ssa_initialized_fn == cfun); |
2973 | ||
2974 | return is_new_name (n) || is_old_name (n); | |
0bca51f0 DN |
2975 | } |
2976 | ||
2977 | ||
0bca51f0 DN |
2978 | /* Mark NAME to be released after update_ssa has finished. */ |
2979 | ||
2980 | void | |
2981 | release_ssa_name_after_update_ssa (tree name) | |
2982 | { | |
5006671f | 2983 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
0bca51f0 DN |
2984 | |
2985 | if (names_to_release == NULL) | |
2986 | names_to_release = BITMAP_ALLOC (NULL); | |
2987 | ||
2988 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2989 | } | |
2990 | ||
2991 | ||
2992 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2993 | frontier information. BLOCKS is the set of blocks to be updated. | |
2994 | ||
2995 | This is slightly different than the regular PHI insertion | |
2996 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2997 | real names (i.e., GIMPLE registers) are inserted: | |
b8698a0f | 2998 | |
0bca51f0 DN |
2999 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
3000 | nodes inside the region affected by the block that defines VAR | |
3001 | and the blocks that define all its replacements. All these | |
84d65814 | 3002 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
3003 | |
3004 | First, we compute the entry point to the region (ENTRY). This is | |
3005 | given by the nearest common dominator to all the definition | |
3006 | blocks. When computing the iterated dominance frontier (IDF), any | |
3007 | block not strictly dominated by ENTRY is ignored. | |
3008 | ||
3009 | We then call the standard PHI insertion algorithm with the pruned | |
3010 | IDF. | |
3011 | ||
3012 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
3013 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
3014 | ||
3015 | static void | |
0fc555fb | 3016 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
0bca51f0 DN |
3017 | unsigned update_flags) |
3018 | { | |
3019 | basic_block entry; | |
3020 | struct def_blocks_d *db; | |
3021 | bitmap idf, pruned_idf; | |
3022 | bitmap_iterator bi; | |
3023 | unsigned i; | |
3024 | ||
0bca51f0 | 3025 | if (TREE_CODE (var) == SSA_NAME) |
77a74ed7 | 3026 | gcc_checking_assert (is_old_name (var)); |
0bca51f0 | 3027 | else |
13714310 | 3028 | gcc_checking_assert (marked_for_renaming (var)); |
0bca51f0 DN |
3029 | |
3030 | /* Get all the definition sites for VAR. */ | |
3031 | db = find_def_blocks_for (var); | |
3032 | ||
3033 | /* No need to do anything if there were no definitions to VAR. */ | |
3034 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3035 | return; | |
3036 | ||
3037 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 3038 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
3039 | pruned_idf = BITMAP_ALLOC (NULL); |
3040 | ||
3041 | if (TREE_CODE (var) == SSA_NAME) | |
3042 | { | |
3043 | if (update_flags == TODO_update_ssa) | |
3044 | { | |
3045 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3046 | only interested in IDF blocks dominated by the nearest | |
3047 | common dominator of all the definition blocks. */ | |
3048 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3049 | db->def_blocks); | |
fefa31b5 | 3050 | if (entry != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
0bca51f0 | 3051 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) |
06e28de2 DM |
3052 | if (BASIC_BLOCK_FOR_FN (cfun, i) != entry |
3053 | && dominated_by_p (CDI_DOMINATORS, | |
3054 | BASIC_BLOCK_FOR_FN (cfun, i), entry)) | |
0bca51f0 DN |
3055 | bitmap_set_bit (pruned_idf, i); |
3056 | } | |
3057 | else | |
3058 | { | |
3059 | /* Otherwise, do not prune the IDF for VAR. */ | |
4ad14919 | 3060 | gcc_checking_assert (update_flags == TODO_update_ssa_full_phi); |
0bca51f0 DN |
3061 | bitmap_copy (pruned_idf, idf); |
3062 | } | |
3063 | } | |
3064 | else | |
3065 | { | |
3066 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3067 | for the first time, so we need to compute the full IDF for | |
3068 | it. */ | |
3069 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
3070 | } |
3071 | ||
3072 | if (!bitmap_empty_p (pruned_idf)) | |
3073 | { | |
3074 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3075 | are included in the region to be updated. The feeding blocks | |
3076 | are important to guarantee that the PHI arguments are renamed | |
3077 | properly. */ | |
38635499 DN |
3078 | |
3079 | /* FIXME, this is not needed if we are updating symbols. We are | |
3080 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
3081 | bitmap_ior_into (blocks, pruned_idf); |
3082 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3083 | { | |
3084 | edge e; | |
3085 | edge_iterator ei; | |
06e28de2 | 3086 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); |
0bca51f0 DN |
3087 | |
3088 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3089 | if (e->src->index >= 0) | |
3090 | bitmap_set_bit (blocks, e->src->index); | |
3091 | } | |
3092 | ||
3093 | insert_phi_nodes_for (var, pruned_idf, true); | |
3094 | } | |
3095 | ||
3096 | BITMAP_FREE (pruned_idf); | |
3097 | BITMAP_FREE (idf); | |
3098 | } | |
3099 | ||
fa5556de RB |
3100 | /* Sort symbols_to_rename after their DECL_UID. */ |
3101 | ||
3102 | static int | |
3103 | insert_updated_phi_nodes_compare_uids (const void *a, const void *b) | |
3104 | { | |
3105 | const_tree syma = *(const const_tree *)a; | |
3106 | const_tree symb = *(const const_tree *)b; | |
3107 | if (DECL_UID (syma) == DECL_UID (symb)) | |
3108 | return 0; | |
3109 | return DECL_UID (syma) < DECL_UID (symb) ? -1 : 1; | |
3110 | } | |
0bca51f0 DN |
3111 | |
3112 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3113 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3114 | ||
3115 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3116 | NEW_SSA_NAMES are all re-written to be reached by the | |
3117 | appropriate definition from NEW_SSA_NAMES. | |
3118 | ||
3119 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3120 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3121 | ||
3122 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
45db3141 | 3123 | calling create_new_def_for to create new defs for names that the |
0bca51f0 DN |
3124 | caller wants to replace. |
3125 | ||
45db3141 RG |
3126 | The caller cretaes the new names to be inserted and the names that need |
3127 | to be replaced by calling create_new_def_for for each old definition | |
3128 | to be replaced. Note that the function assumes that the | |
3129 | new defining statement has already been inserted in the IL. | |
0bca51f0 DN |
3130 | |
3131 | For instance, given the following code: | |
3132 | ||
3133 | 1 L0: | |
3134 | 2 x_1 = PHI (0, x_5) | |
3135 | 3 if (x_1 < 10) | |
3136 | 4 if (x_1 > 7) | |
3137 | 5 y_2 = 0 | |
3138 | 6 else | |
3139 | 7 y_3 = x_1 + x_7 | |
3140 | 8 endif | |
3141 | 9 x_5 = x_1 + 1 | |
3142 | 10 goto L0; | |
3143 | 11 endif | |
3144 | ||
3145 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3146 | ||
3147 | 1 L0: | |
3148 | 2 x_1 = PHI (0, x_5) | |
3149 | 3 if (x_1 < 10) | |
3150 | 4 x_10 = ... | |
3151 | 5 if (x_1 > 7) | |
3152 | 6 y_2 = 0 | |
3153 | 7 else | |
3154 | 8 x_11 = ... | |
3155 | 9 y_3 = x_1 + x_7 | |
3156 | 10 endif | |
3157 | 11 x_5 = x_1 + 1 | |
3158 | 12 goto L0; | |
3159 | 13 endif | |
3160 | ||
3161 | We want to replace all the uses of x_1 with the new definitions of | |
3162 | x_10 and x_11. Note that the only uses that should be replaced are | |
3163 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3164 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3165 | renaming). | |
3166 | ||
3167 | Additionally, we may need to insert a PHI node at line 11 because | |
3168 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3169 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3170 | nodes is optional. They are not strictly necessary to preserve the | |
3171 | SSA form, and depending on what the caller inserted, they may not | |
3172 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3173 | aspects of how update_ssa operates, see the documentation for | |
3174 | TODO_update_ssa*. */ | |
3175 | ||
3176 | void | |
3177 | update_ssa (unsigned update_flags) | |
3178 | { | |
0bca51f0 DN |
3179 | basic_block bb, start_bb; |
3180 | bitmap_iterator bi; | |
dfea6c85 | 3181 | unsigned i = 0; |
0bca51f0 | 3182 | bool insert_phi_p; |
b6e7e9af | 3183 | sbitmap_iterator sbi; |
13714310 | 3184 | tree sym; |
0bca51f0 | 3185 | |
580b2c2e SB |
3186 | /* Only one update flag should be set. */ |
3187 | gcc_assert (update_flags == TODO_update_ssa | |
3188 | || update_flags == TODO_update_ssa_no_phi | |
3189 | || update_flags == TODO_update_ssa_full_phi | |
3190 | || update_flags == TODO_update_ssa_only_virtuals); | |
3191 | ||
5006671f | 3192 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
3193 | return; |
3194 | ||
90ad8d00 TV |
3195 | #ifdef ENABLE_CHECKING |
3196 | timevar_push (TV_TREE_STMT_VERIFY); | |
3197 | ||
3198 | bool err = false; | |
3199 | ||
3200 | FOR_EACH_BB_FN (bb, cfun) | |
3201 | { | |
3202 | gimple_stmt_iterator gsi; | |
3203 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
3204 | { | |
3205 | gimple stmt = gsi_stmt (gsi); | |
3206 | ||
3207 | ssa_op_iter i; | |
3208 | use_operand_p use_p; | |
3209 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) | |
3210 | { | |
3211 | tree use = USE_FROM_PTR (use_p); | |
3212 | if (TREE_CODE (use) != SSA_NAME) | |
3213 | continue; | |
3214 | ||
3215 | if (SSA_NAME_IN_FREE_LIST (use)) | |
3216 | { | |
3217 | error ("statement uses released SSA name:"); | |
3218 | debug_gimple_stmt (stmt); | |
3219 | fprintf (stderr, "The use of "); | |
3220 | print_generic_expr (stderr, use, 0); | |
3221 | fprintf (stderr," should have been replaced\n"); | |
3222 | err = true; | |
3223 | } | |
3224 | } | |
3225 | } | |
3226 | } | |
3227 | ||
3228 | if (err) | |
3229 | internal_error ("cannot update SSA form"); | |
3230 | ||
3231 | timevar_pop (TV_TREE_STMT_VERIFY); | |
3232 | #endif | |
3233 | ||
0bca51f0 DN |
3234 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
3235 | ||
427f99e2 MJ |
3236 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3237 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3238 | ||
5006671f RG |
3239 | if (!update_ssa_initialized_fn) |
3240 | init_update_ssa (cfun); | |
580b2c2e SB |
3241 | else if (update_flags == TODO_update_ssa_only_virtuals) |
3242 | { | |
3243 | /* If we only need to update virtuals, remove all the mappings for | |
3244 | real names before proceeding. The caller is responsible for | |
3245 | having dealt with the name mappings before calling update_ssa. */ | |
f61e445a LC |
3246 | bitmap_clear (old_ssa_names); |
3247 | bitmap_clear (new_ssa_names); | |
580b2c2e SB |
3248 | } |
3249 | ||
5006671f RG |
3250 | gcc_assert (update_ssa_initialized_fn == cfun); |
3251 | ||
2ce79879 | 3252 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
9771b263 | 3253 | if (!phis_to_rewrite.exists ()) |
8b1c6fd7 | 3254 | phis_to_rewrite.create (last_basic_block_for_fn (cfun) + 1); |
95dd3097 | 3255 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3256 | |
0bca51f0 DN |
3257 | /* Ensure that the dominance information is up-to-date. */ |
3258 | calculate_dominance_info (CDI_DOMINATORS); | |
3259 | ||
84d65814 | 3260 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 | 3261 | |
84d65814 DN |
3262 | /* If there are names defined in the replacement table, prepare |
3263 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3264 | OLD_SSA_NAMES. */ | |
f61e445a | 3265 | if (bitmap_first_set_bit (new_ssa_names) >= 0) |
84d65814 | 3266 | { |
95dd3097 | 3267 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3268 | |
3269 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3270 | removal, and there are no symbols to rename, then there's | |
3271 | nothing else to do. */ | |
f61e445a | 3272 | if (bitmap_first_set_bit (new_ssa_names) < 0 |
13714310 | 3273 | && !cfun->gimple_df->ssa_renaming_needed) |
84d65814 DN |
3274 | goto done; |
3275 | } | |
3276 | ||
3277 | /* Next, determine the block at which to start the renaming process. */ | |
13714310 | 3278 | if (cfun->gimple_df->ssa_renaming_needed) |
84d65814 | 3279 | { |
b4e209fd RG |
3280 | /* If we rename bare symbols initialize the mapping to |
3281 | auxiliar info we need to keep track of. */ | |
c203e8a7 | 3282 | var_infos = new hash_table<var_info_hasher> (47); |
b4e209fd | 3283 | |
84d65814 DN |
3284 | /* If we have to rename some symbols from scratch, we need to |
3285 | start the process at the root of the CFG. FIXME, it should | |
3286 | be possible to determine the nearest block that had a | |
3287 | definition for each of the symbols that are marked for | |
3288 | updating. For now this seems more work than it's worth. */ | |
fefa31b5 | 3289 | start_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
84d65814 | 3290 | |
38635499 | 3291 | /* Traverse the CFG looking for existing definitions and uses of |
13714310 | 3292 | symbols in SSA operands. Mark interesting blocks and |
38635499 DN |
3293 | statements and set local live-in information for the PHI |
3294 | placement heuristics. */ | |
95dd3097 | 3295 | prepare_block_for_update (start_bb, insert_phi_p); |
343c5d46 RG |
3296 | |
3297 | #ifdef ENABLE_CHECKING | |
3298 | for (i = 1; i < num_ssa_names; ++i) | |
3299 | { | |
3300 | tree name = ssa_name (i); | |
3301 | if (!name | |
3302 | || virtual_operand_p (name)) | |
3303 | continue; | |
3304 | ||
3305 | /* For all but virtual operands, which do not have SSA names | |
3306 | with overlapping life ranges, ensure that symbols marked | |
3307 | for renaming do not have existing SSA names associated with | |
3308 | them as we do not re-write them out-of-SSA before going | |
3309 | into SSA for the remaining symbol uses. */ | |
3310 | if (marked_for_renaming (SSA_NAME_VAR (name))) | |
3311 | { | |
3312 | fprintf (stderr, "Existing SSA name for symbol marked for " | |
3313 | "renaming: "); | |
3314 | print_generic_expr (stderr, name, TDF_SLIM); | |
3315 | fprintf (stderr, "\n"); | |
3316 | internal_error ("SSA corruption"); | |
3317 | } | |
3318 | } | |
3319 | #endif | |
0bca51f0 DN |
3320 | } |
3321 | else | |
84d65814 DN |
3322 | { |
3323 | /* Otherwise, the entry block to the region is the nearest | |
3324 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3325 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3326 | blocks_to_update); | |
84d65814 | 3327 | } |
0bca51f0 DN |
3328 | |
3329 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3330 | of every block, creating new definitions for names in OLD_SSA_NAMES |
13714310 | 3331 | and for symbols found. */ |
0bca51f0 DN |
3332 | if (insert_phi_p) |
3333 | { | |
0fc555fb | 3334 | bitmap_head *dfs; |
9caf90a8 KH |
3335 | |
3336 | /* If the caller requested PHI nodes to be added, compute | |
3337 | dominance frontiers. */ | |
8b1c6fd7 | 3338 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
11cd3bed | 3339 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3340 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
9caf90a8 KH |
3341 | compute_dominance_frontiers (dfs); |
3342 | ||
f61e445a | 3343 | if (bitmap_first_set_bit (old_ssa_names) >= 0) |
0bca51f0 | 3344 | { |
b6e7e9af KH |
3345 | sbitmap_iterator sbi; |
3346 | ||
84d65814 DN |
3347 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3348 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3349 | will grow while we are traversing it (but it will not | |
3350 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3351 | for traversal. */ | |
5829cc0f | 3352 | sbitmap tmp = sbitmap_alloc (SBITMAP_SIZE (old_ssa_names)); |
f61e445a | 3353 | bitmap_copy (tmp, old_ssa_names); |
d4ac4ce2 | 3354 | EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi) |
95dd3097 | 3355 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3356 | update_flags); |
0bca51f0 DN |
3357 | sbitmap_free (tmp); |
3358 | } | |
3359 | ||
fa5556de | 3360 | symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids); |
9771b263 | 3361 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
13714310 | 3362 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, |
38635499 | 3363 | update_flags); |
0bca51f0 | 3364 | |
11cd3bed | 3365 | FOR_EACH_BB_FN (bb, cfun) |
0fc555fb | 3366 | bitmap_clear (&dfs[bb->index]); |
9caf90a8 KH |
3367 | free (dfs); |
3368 | ||
0bca51f0 DN |
3369 | /* Insertion of PHI nodes may have added blocks to the region. |
3370 | We need to re-compute START_BB to include the newly added | |
3371 | blocks. */ | |
fefa31b5 | 3372 | if (start_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
95dd3097 ZD |
3373 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3374 | blocks_to_update); | |
0bca51f0 DN |
3375 | } |
3376 | ||
3377 | /* Reset the current definition for name and symbol before renaming | |
3378 | the sub-graph. */ | |
d4ac4ce2 | 3379 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
8812aab1 | 3380 | get_ssa_name_ann (ssa_name (i))->info.current_def = NULL_TREE; |
0bca51f0 | 3381 | |
9771b263 | 3382 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
8812aab1 | 3383 | get_var_info (sym)->info.current_def = NULL_TREE; |
0bca51f0 DN |
3384 | |
3385 | /* Now start the renaming process at START_BB. */ | |
8b1c6fd7 | 3386 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
f61e445a | 3387 | bitmap_clear (interesting_blocks); |
95dd3097 | 3388 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
d7c028c0 | 3389 | bitmap_set_bit (interesting_blocks, i); |
0bca51f0 | 3390 | |
ccf5c864 | 3391 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
0bca51f0 | 3392 | |
ccf5c864 | 3393 | sbitmap_free (interesting_blocks); |
0bca51f0 DN |
3394 | |
3395 | /* Debugging dumps. */ | |
3396 | if (dump_file) | |
3397 | { | |
3398 | int c; | |
3399 | unsigned i; | |
3400 | ||
84d65814 | 3401 | dump_update_ssa (dump_file); |
0bca51f0 | 3402 | |
427f99e2 | 3403 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
0bca51f0 DN |
3404 | start_bb->index); |
3405 | ||
3406 | c = 0; | |
95dd3097 | 3407 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 | 3408 | c++; |
8b1c6fd7 DM |
3409 | fprintf (dump_file, "Number of blocks in CFG: %d\n", |
3410 | last_basic_block_for_fn (cfun)); | |
427f99e2 | 3411 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
8b1c6fd7 | 3412 | c, PERCENT (c, last_basic_block_for_fn (cfun))); |
0bca51f0 DN |
3413 | |
3414 | if (dump_flags & TDF_DETAILS) | |
3415 | { | |
0eb09f31 | 3416 | fprintf (dump_file, "Affected blocks:"); |
95dd3097 | 3417 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0eb09f31 | 3418 | fprintf (dump_file, " %u", i); |
0bca51f0 DN |
3419 | fprintf (dump_file, "\n"); |
3420 | } | |
3421 | ||
3422 | fprintf (dump_file, "\n\n"); | |
3423 | } | |
3424 | ||
3425 | /* Free allocated memory. */ | |
84d65814 | 3426 | done: |
0bca51f0 DN |
3427 | delete_update_ssa (); |
3428 | ||
3429 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3430 | } |