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4ee9c684 | 1 | /* Rewrite a program in Normal form into SSA. |
841424cc | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011 |
8c4c00c1 | 3 | Free Software Foundation, Inc. |
4ee9c684 | 4 | Contributed by Diego Novillo <dnovillo@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 10 | the Free Software Foundation; either version 3, or (at your option) |
4ee9c684 | 11 | any later version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
4ee9c684 | 28 | #include "tm_p.h" |
29 | #include "langhooks.h" | |
4ee9c684 | 30 | #include "basic-block.h" |
4ee9c684 | 31 | #include "function.h" |
ce084dfc | 32 | #include "gimple-pretty-print.h" |
4ee9c684 | 33 | #include "bitmap.h" |
34 | #include "tree-flow.h" | |
75a70cf9 | 35 | #include "gimple.h" |
4ee9c684 | 36 | #include "tree-inline.h" |
4ee9c684 | 37 | #include "hashtab.h" |
4ee9c684 | 38 | #include "tree-pass.h" |
39 | #include "cfgloop.h" | |
40 | #include "domwalk.h" | |
095dcfa3 | 41 | #include "params.h" |
b4fa1427 | 42 | #include "diagnostic-core.h" |
4ee9c684 | 43 | |
75a70cf9 | 44 | |
4ee9c684 | 45 | /* This file builds the SSA form for a function as described in: |
46 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
47 | Computing Static Single Assignment Form and the Control Dependence | |
48 | Graph. ACM Transactions on Programming Languages and Systems, | |
49 | 13(4):451-490, October 1991. */ | |
50 | ||
4ee9c684 | 51 | /* Structure to map a variable VAR to the set of blocks that contain |
52 | definitions for VAR. */ | |
53 | struct def_blocks_d | |
54 | { | |
4ee9c684 | 55 | /* Blocks that contain definitions of VAR. Bit I will be set if the |
56 | Ith block contains a definition of VAR. */ | |
57 | bitmap def_blocks; | |
58 | ||
e551bd1a | 59 | /* Blocks that contain a PHI node for VAR. */ |
f3d9a16c | 60 | bitmap phi_blocks; |
61 | ||
4ee9c684 | 62 | /* Blocks where VAR is live-on-entry. Similar semantics as |
63 | DEF_BLOCKS. */ | |
64 | bitmap livein_blocks; | |
65 | }; | |
66 | ||
c86a4051 | 67 | typedef struct def_blocks_d *def_blocks_p; |
68 | ||
4ee9c684 | 69 | |
dd2d357d | 70 | /* Stack of trees used to restore the global currdefs to its original |
88dbf20f | 71 | state after completing rewriting of a block and its dominator |
72 | children. Its elements have the following properties: | |
dd2d357d | 73 | |
4fb5e5ca | 74 | - An SSA_NAME (N) indicates that the current definition of the |
75 | underlying variable should be set to the given SSA_NAME. If the | |
76 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
77 | next slot in the stack must be a _DECL node (SYM). In this case, | |
78 | the name N in the previous slot is the current reaching | |
79 | definition for SYM. | |
dd2d357d | 80 | |
88dbf20f | 81 | - A _DECL node indicates that the underlying variable has no |
82 | current definition. | |
e551bd1a | 83 | |
4fb5e5ca | 84 | - A NULL node at the top entry is used to mark the last slot |
88dbf20f | 85 | associated with the current block. */ |
f1f41a6c | 86 | static vec<tree> block_defs_stack; |
486b57c7 | 87 | |
75a70cf9 | 88 | |
88dbf20f | 89 | /* Set of existing SSA names being replaced by update_ssa. */ |
90 | static sbitmap old_ssa_names; | |
91 | ||
92 | /* Set of new SSA names being added by update_ssa. Note that both | |
93 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
94 | the operations done on them are presence tests. */ | |
95 | static sbitmap new_ssa_names; | |
96 | ||
6bf320fb | 97 | sbitmap interesting_blocks; |
75a70cf9 | 98 | |
88dbf20f | 99 | /* Set of SSA names that have been marked to be released after they |
100 | were registered in the replacement table. They will be finally | |
101 | released after we finish updating the SSA web. */ | |
102 | static bitmap names_to_release; | |
103 | ||
f1f41a6c | 104 | /* vec of vec of PHIs to rewrite in a basic block. Element I corresponds |
2670407e | 105 | the to basic block with index I. Allocated once per compilation, *not* |
106 | released between different functions. */ | |
f1f41a6c | 107 | static vec<gimple_vec> phis_to_rewrite; |
70630fcd | 108 | |
109 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
70630fcd | 110 | static bitmap blocks_with_phis_to_rewrite; |
111 | ||
88dbf20f | 112 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
0dc262e0 | 113 | to grow as the callers to create_new_def_for will create new names on |
114 | the fly. | |
115 | FIXME. Currently set to 1/3 to avoid frequent reallocations but still | |
116 | need to find a reasonable growth strategy. */ | |
88dbf20f | 117 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) |
118 | ||
88dbf20f | 119 | |
dd277d48 | 120 | /* The function the SSA updating data structures have been initialized for. |
0dc262e0 | 121 | NULL if they need to be initialized by create_new_def_for. */ |
dd277d48 | 122 | static struct function *update_ssa_initialized_fn = NULL; |
88dbf20f | 123 | |
4ee9c684 | 124 | /* Global data to attach to the main dominator walk structure. */ |
125 | struct mark_def_sites_global_data | |
126 | { | |
88dbf20f | 127 | /* This bitmap contains the variables which are set before they |
128 | are used in a basic block. */ | |
ecddc799 | 129 | bitmap kills; |
4ee9c684 | 130 | }; |
131 | ||
74105c0d | 132 | /* Information stored for both SSA names and decls. */ |
133 | struct common_info_d | |
22d6c74e | 134 | { |
22d6c74e | 135 | /* This field indicates whether or not the variable may need PHI nodes. |
136 | See the enum's definition for more detailed information about the | |
137 | states. */ | |
138 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
139 | ||
74105c0d | 140 | /* The current reaching definition replacing this var. */ |
22d6c74e | 141 | tree current_def; |
142 | ||
74105c0d | 143 | /* Definitions for this var. */ |
22d6c74e | 144 | struct def_blocks_d def_blocks; |
145 | }; | |
146 | ||
74105c0d | 147 | /* The information associated with decls and SSA names. */ |
148 | typedef struct common_info_d *common_info_p; | |
149 | ||
150 | /* Information stored for decls. */ | |
151 | struct var_info_d | |
152 | { | |
153 | /* The variable. */ | |
154 | tree var; | |
155 | ||
156 | /* Information stored for both SSA names and decls. */ | |
157 | struct common_info_d info; | |
158 | }; | |
159 | ||
22d6c74e | 160 | /* The information associated with decls. */ |
161 | typedef struct var_info_d *var_info_p; | |
162 | ||
22d6c74e | 163 | |
164 | /* Each entry in VAR_INFOS contains an element of type STRUCT | |
165 | VAR_INFO_D. */ | |
166 | static htab_t var_infos; | |
167 | ||
168 | ||
88dbf20f | 169 | /* Information stored for SSA names. */ |
f3d9a16c | 170 | struct ssa_name_info |
171 | { | |
5eeafc2d | 172 | /* Age of this record (so that info_for_ssa_name table can be cleared |
173 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
174 | are assumed to be null. */ | |
175 | unsigned age; | |
2920559d | 176 | |
5eeafc2d | 177 | /* Replacement mappings, allocated from update_ssa_obstack. */ |
178 | bitmap repl_set; | |
22d6c74e | 179 | |
74105c0d | 180 | /* Information stored for both SSA names and decls. */ |
181 | struct common_info_d info; | |
f3d9a16c | 182 | }; |
4ee9c684 | 183 | |
2920559d | 184 | /* The information associated with names. */ |
185 | typedef struct ssa_name_info *ssa_name_info_p; | |
2920559d | 186 | |
f1f41a6c | 187 | static vec<ssa_name_info_p> info_for_ssa_name; |
2920559d | 188 | static unsigned current_info_for_ssa_name_age; |
189 | ||
5eeafc2d | 190 | static bitmap_obstack update_ssa_obstack; |
191 | ||
2920559d | 192 | /* The set of blocks affected by update_ssa. */ |
2920559d | 193 | static bitmap blocks_to_update; |
4ee9c684 | 194 | |
88dbf20f | 195 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
196 | called several times to do different, but related, tasks. | |
197 | Initially, we need it to rename the whole program into SSA form. | |
198 | At other times, we may need it to only rename into SSA newly | |
199 | exposed symbols. Finally, we can also call it to incrementally fix | |
200 | an already built SSA web. */ | |
201 | enum rewrite_mode { | |
202 | /* Convert the whole function into SSA form. */ | |
203 | REWRITE_ALL, | |
204 | ||
205 | /* Incrementally update the SSA web by replacing existing SSA | |
206 | names with new ones. See update_ssa for details. */ | |
207 | REWRITE_UPDATE | |
208 | }; | |
209 | ||
210 | ||
88dbf20f | 211 | |
6cf80e5b | 212 | |
095dcfa3 | 213 | /* Prototypes for debugging functions. */ |
214 | extern void dump_tree_ssa (FILE *); | |
215 | extern void debug_tree_ssa (void); | |
216 | extern void debug_def_blocks (void); | |
217 | extern void dump_tree_ssa_stats (FILE *); | |
218 | extern void debug_tree_ssa_stats (void); | |
4fb5e5ca | 219 | extern void dump_update_ssa (FILE *); |
220 | extern void debug_update_ssa (void); | |
221 | extern void dump_names_replaced_by (FILE *, tree); | |
222 | extern void debug_names_replaced_by (tree); | |
22d6c74e | 223 | extern void dump_var_infos (FILE *); |
224 | extern void debug_var_infos (void); | |
4fb5e5ca | 225 | extern void dump_defs_stack (FILE *, int); |
226 | extern void debug_defs_stack (int); | |
227 | extern void dump_currdefs (FILE *); | |
228 | extern void debug_currdefs (void); | |
095dcfa3 | 229 | |
e70e8b13 | 230 | |
231 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ | |
232 | static bitmap symbols_to_rename_set; | |
f1f41a6c | 233 | static vec<tree> symbols_to_rename; |
e70e8b13 | 234 | |
235 | /* Mark SYM for renaming. */ | |
236 | ||
237 | static void | |
238 | mark_for_renaming (tree sym) | |
239 | { | |
240 | if (!symbols_to_rename_set) | |
241 | symbols_to_rename_set = BITMAP_ALLOC (NULL); | |
242 | if (bitmap_set_bit (symbols_to_rename_set, DECL_UID (sym))) | |
f1f41a6c | 243 | symbols_to_rename.safe_push (sym); |
e70e8b13 | 244 | } |
245 | ||
246 | /* Return true if SYM is marked for renaming. */ | |
247 | ||
248 | static bool | |
249 | marked_for_renaming (tree sym) | |
250 | { | |
ec11736b | 251 | if (!symbols_to_rename_set || sym == NULL_TREE) |
e70e8b13 | 252 | return false; |
253 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
254 | } | |
255 | ||
256 | ||
75a70cf9 | 257 | /* Return true if STMT needs to be rewritten. When renaming a subset |
258 | of the variables, not all statements will be processed. This is | |
259 | decided in mark_def_sites. */ | |
260 | ||
261 | static inline bool | |
262 | rewrite_uses_p (gimple stmt) | |
263 | { | |
264 | return gimple_visited_p (stmt); | |
265 | } | |
266 | ||
267 | ||
268 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
269 | ||
270 | static inline void | |
271 | set_rewrite_uses (gimple stmt, bool rewrite_p) | |
272 | { | |
273 | gimple_set_visited (stmt, rewrite_p); | |
274 | } | |
275 | ||
276 | ||
277 | /* Return true if the DEFs created by statement STMT should be | |
278 | registered when marking new definition sites. This is slightly | |
279 | different than rewrite_uses_p: it's used by update_ssa to | |
280 | distinguish statements that need to have both uses and defs | |
281 | processed from those that only need to have their defs processed. | |
282 | Statements that define new SSA names only need to have their defs | |
283 | registered, but they don't need to have their uses renamed. */ | |
284 | ||
285 | static inline bool | |
286 | register_defs_p (gimple stmt) | |
287 | { | |
288 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
289 | } | |
290 | ||
291 | ||
292 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
293 | ||
294 | static inline void | |
295 | set_register_defs (gimple stmt, bool register_defs_p) | |
296 | { | |
297 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
298 | } | |
299 | ||
300 | ||
f3d9a16c | 301 | /* Get the information associated with NAME. */ |
302 | ||
4fb5e5ca | 303 | static inline ssa_name_info_p |
f3d9a16c | 304 | get_ssa_name_ann (tree name) |
305 | { | |
2920559d | 306 | unsigned ver = SSA_NAME_VERSION (name); |
f1f41a6c | 307 | unsigned len = info_for_ssa_name.length (); |
2920559d | 308 | struct ssa_name_info *info; |
309 | ||
83b709f2 | 310 | /* Re-allocate the vector at most once per update/into-SSA. */ |
2920559d | 311 | if (ver >= len) |
f1f41a6c | 312 | info_for_ssa_name.safe_grow_cleared (num_ssa_names); |
83b709f2 | 313 | |
314 | /* But allocate infos lazily. */ | |
f1f41a6c | 315 | info = info_for_ssa_name[ver]; |
83b709f2 | 316 | if (!info) |
2920559d | 317 | { |
83b709f2 | 318 | info = XCNEW (struct ssa_name_info); |
319 | info->age = current_info_for_ssa_name_age; | |
320 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
f1f41a6c | 321 | info_for_ssa_name[ver] = info; |
2920559d | 322 | } |
323 | ||
2920559d | 324 | if (info->age < current_info_for_ssa_name_age) |
325 | { | |
2920559d | 326 | info->age = current_info_for_ssa_name_age; |
74105c0d | 327 | info->repl_set = NULL; |
328 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
329 | info->info.current_def = NULL_TREE; | |
330 | info->info.def_blocks.def_blocks = NULL; | |
331 | info->info.def_blocks.phi_blocks = NULL; | |
332 | info->info.def_blocks.livein_blocks = NULL; | |
2920559d | 333 | } |
f3d9a16c | 334 | |
2920559d | 335 | return info; |
f3d9a16c | 336 | } |
337 | ||
22d6c74e | 338 | /* Return and allocate the auxiliar information for DECL. */ |
339 | ||
340 | static inline var_info_p | |
341 | get_var_info (tree decl) | |
342 | { | |
343 | struct var_info_d vi; | |
344 | void **slot; | |
345 | vi.var = decl; | |
346 | slot = htab_find_slot_with_hash (var_infos, &vi, DECL_UID (decl), INSERT); | |
347 | if (*slot == NULL) | |
348 | { | |
349 | var_info_p v = XCNEW (struct var_info_d); | |
350 | v->var = decl; | |
351 | *slot = (void *)v; | |
352 | return v; | |
353 | } | |
354 | return (var_info_p) *slot; | |
355 | } | |
356 | ||
4fb5e5ca | 357 | |
358 | /* Clears info for SSA names. */ | |
2920559d | 359 | |
360 | static void | |
361 | clear_ssa_name_info (void) | |
362 | { | |
363 | current_info_for_ssa_name_age++; | |
5eeafc2d | 364 | |
365 | /* If current_info_for_ssa_name_age wraps we use stale information. | |
366 | Asser that this does not happen. */ | |
367 | gcc_assert (current_info_for_ssa_name_age != 0); | |
2920559d | 368 | } |
e551bd1a | 369 | |
4fb5e5ca | 370 | |
74105c0d | 371 | /* Get access to the auxiliar information stored per SSA name or decl. */ |
f3d9a16c | 372 | |
74105c0d | 373 | static inline common_info_p |
374 | get_common_info (tree var) | |
f3d9a16c | 375 | { |
376 | if (TREE_CODE (var) == SSA_NAME) | |
74105c0d | 377 | return &get_ssa_name_ann (var)->info; |
f3d9a16c | 378 | else |
74105c0d | 379 | return &get_var_info (var)->info; |
f3d9a16c | 380 | } |
381 | ||
e551bd1a | 382 | |
f3d9a16c | 383 | /* Return the current definition for VAR. */ |
384 | ||
095dcfa3 | 385 | tree |
f3d9a16c | 386 | get_current_def (tree var) |
387 | { | |
74105c0d | 388 | return get_common_info (var)->current_def; |
f3d9a16c | 389 | } |
390 | ||
e551bd1a | 391 | |
f3d9a16c | 392 | /* Sets current definition of VAR to DEF. */ |
393 | ||
095dcfa3 | 394 | void |
f3d9a16c | 395 | set_current_def (tree var, tree def) |
396 | { | |
74105c0d | 397 | get_common_info (var)->current_def = def; |
f3d9a16c | 398 | } |
399 | ||
2920559d | 400 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
401 | all statements in basic block BB. */ | |
402 | ||
403 | static void | |
404 | initialize_flags_in_bb (basic_block bb) | |
405 | { | |
75a70cf9 | 406 | gimple stmt; |
407 | gimple_stmt_iterator gsi; | |
2920559d | 408 | |
75a70cf9 | 409 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 410 | { |
75a70cf9 | 411 | gimple phi = gsi_stmt (gsi); |
412 | set_rewrite_uses (phi, false); | |
413 | set_register_defs (phi, false); | |
2920559d | 414 | } |
415 | ||
75a70cf9 | 416 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 417 | { |
75a70cf9 | 418 | stmt = gsi_stmt (gsi); |
419 | ||
2920559d | 420 | /* We are going to use the operand cache API, such as |
421 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
422 | cache for each statement should be up-to-date. */ | |
88536563 | 423 | gcc_checking_assert (!gimple_modified_p (stmt)); |
75a70cf9 | 424 | set_rewrite_uses (stmt, false); |
425 | set_register_defs (stmt, false); | |
2920559d | 426 | } |
427 | } | |
428 | ||
429 | /* Mark block BB as interesting for update_ssa. */ | |
430 | ||
431 | static void | |
432 | mark_block_for_update (basic_block bb) | |
433 | { | |
88536563 | 434 | gcc_checking_assert (blocks_to_update != NULL); |
39192870 | 435 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
2920559d | 436 | return; |
2920559d | 437 | initialize_flags_in_bb (bb); |
438 | } | |
439 | ||
e551bd1a | 440 | /* Return the set of blocks where variable VAR is defined and the blocks |
441 | where VAR is live on entry (livein). If no entry is found in | |
442 | DEF_BLOCKS, a new one is created and returned. */ | |
4ee9c684 | 443 | |
e551bd1a | 444 | static inline struct def_blocks_d * |
74105c0d | 445 | get_def_blocks_for (common_info_p info) |
4ee9c684 | 446 | { |
74105c0d | 447 | struct def_blocks_d *db_p = &info->def_blocks; |
22d6c74e | 448 | if (!db_p->def_blocks) |
4ee9c684 | 449 | { |
22d6c74e | 450 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
451 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
452 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
2cf24776 | 453 | } |
454 | ||
e551bd1a | 455 | return db_p; |
4ee9c684 | 456 | } |
457 | ||
6cf80e5b | 458 | |
f3d9a16c | 459 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
88dbf20f | 460 | VAR is defined by a PHI node. */ |
4ee9c684 | 461 | |
462 | static void | |
88dbf20f | 463 | set_def_block (tree var, basic_block bb, bool phi_p) |
4ee9c684 | 464 | { |
465 | struct def_blocks_d *db_p; | |
74105c0d | 466 | common_info_p info; |
ce898113 | 467 | |
74105c0d | 468 | info = get_common_info (var); |
469 | db_p = get_def_blocks_for (info); | |
4ee9c684 | 470 | |
471 | /* Set the bit corresponding to the block where VAR is defined. */ | |
472 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
f3d9a16c | 473 | if (phi_p) |
474 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
4ee9c684 | 475 | |
e551bd1a | 476 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 477 | |
478 | If we are in the UNKNOWN state, then this is the first definition | |
479 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
e551bd1a | 480 | we do not need a PHI node for this variable at this time (i.e., |
4ee9c684 | 481 | transition to NEED_PHI_STATE_NO). |
482 | ||
483 | If we are in any other state, then we either have multiple definitions | |
484 | of this variable occurring in different blocks or we saw a use of the | |
485 | variable which was not dominated by the block containing the | |
486 | definition(s). In this case we may need a PHI node, so enter | |
487 | state NEED_PHI_STATE_MAYBE. */ | |
74105c0d | 488 | if (info->need_phi_state == NEED_PHI_STATE_UNKNOWN) |
489 | info->need_phi_state = NEED_PHI_STATE_NO; | |
4ee9c684 | 490 | else |
74105c0d | 491 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 492 | } |
493 | ||
494 | ||
495 | /* Mark block BB as having VAR live at the entry to BB. */ | |
496 | ||
497 | static void | |
498 | set_livein_block (tree var, basic_block bb) | |
499 | { | |
74105c0d | 500 | common_info_p info; |
4ee9c684 | 501 | struct def_blocks_d *db_p; |
4ee9c684 | 502 | |
74105c0d | 503 | info = get_common_info (var); |
504 | db_p = get_def_blocks_for (info); | |
4ee9c684 | 505 | |
506 | /* Set the bit corresponding to the block where VAR is live in. */ | |
507 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
508 | ||
e551bd1a | 509 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 510 | |
511 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
512 | by the single block containing the definition(s) of this variable. If | |
513 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
514 | NEED_PHI_STATE_MAYBE. */ | |
74105c0d | 515 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
4ee9c684 | 516 | { |
517 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
518 | ||
519 | if (def_block_index == -1 | |
520 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
521 | BASIC_BLOCK (def_block_index))) | |
74105c0d | 522 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 523 | } |
524 | else | |
74105c0d | 525 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 526 | } |
527 | ||
528 | ||
88dbf20f | 529 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
4ee9c684 | 530 | |
88dbf20f | 531 | static inline bool |
532 | is_old_name (tree name) | |
533 | { | |
095dcfa3 | 534 | unsigned ver = SSA_NAME_VERSION (name); |
dd277d48 | 535 | if (!new_ssa_names) |
536 | return false; | |
156093aa | 537 | return (ver < SBITMAP_SIZE (new_ssa_names) |
08b7917c | 538 | && bitmap_bit_p (old_ssa_names, ver)); |
88dbf20f | 539 | } |
540 | ||
541 | ||
542 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
ce898113 | 543 | |
88dbf20f | 544 | static inline bool |
545 | is_new_name (tree name) | |
546 | { | |
095dcfa3 | 547 | unsigned ver = SSA_NAME_VERSION (name); |
dd277d48 | 548 | if (!new_ssa_names) |
549 | return false; | |
156093aa | 550 | return (ver < SBITMAP_SIZE (new_ssa_names) |
08b7917c | 551 | && bitmap_bit_p (new_ssa_names, ver)); |
4ee9c684 | 552 | } |
553 | ||
e551bd1a | 554 | |
f4e36c33 | 555 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
88dbf20f | 556 | |
557 | static inline bitmap | |
f4e36c33 | 558 | names_replaced_by (tree new_tree) |
88dbf20f | 559 | { |
5eeafc2d | 560 | return get_ssa_name_ann (new_tree)->repl_set; |
88dbf20f | 561 | } |
562 | ||
563 | ||
f4e36c33 | 564 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
88dbf20f | 565 | |
566 | static inline void | |
f4e36c33 | 567 | add_to_repl_tbl (tree new_tree, tree old) |
88dbf20f | 568 | { |
5eeafc2d | 569 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
570 | if (!*set) | |
571 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
572 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
88dbf20f | 573 | } |
574 | ||
575 | ||
f4e36c33 | 576 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
88dbf20f | 577 | represents the set of names O_1 ... O_j replaced by N_i. This is |
578 | used by update_ssa and its helpers to introduce new SSA names in an | |
579 | already formed SSA web. */ | |
580 | ||
581 | static void | |
f4e36c33 | 582 | add_new_name_mapping (tree new_tree, tree old) |
88dbf20f | 583 | { |
f4e36c33 | 584 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
88536563 | 585 | gcc_checking_assert (new_tree != old |
586 | && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
095dcfa3 | 587 | |
4fb5e5ca | 588 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
589 | caller may have created new names since the set was created. */ | |
156093aa | 590 | if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1) |
4fb5e5ca | 591 | { |
592 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
593 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
594 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
88dbf20f | 595 | } |
596 | ||
88dbf20f | 597 | /* Update the REPL_TBL table. */ |
f4e36c33 | 598 | add_to_repl_tbl (new_tree, old); |
56004dc5 | 599 | |
88dbf20f | 600 | /* If OLD had already been registered as a new name, then all the |
f4e36c33 | 601 | names that OLD replaces should also be replaced by NEW_TREE. */ |
88dbf20f | 602 | if (is_new_name (old)) |
f4e36c33 | 603 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
88dbf20f | 604 | |
f4e36c33 | 605 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
88dbf20f | 606 | respectively. */ |
08b7917c | 607 | bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
608 | bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old)); | |
56004dc5 | 609 | } |
4ee9c684 | 610 | |
4ee9c684 | 611 | |
e551bd1a | 612 | /* Call back for walk_dominator_tree used to collect definition sites |
613 | for every variable in the function. For every statement S in block | |
614 | BB: | |
4ee9c684 | 615 | |
b66731e8 | 616 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
6bf320fb | 617 | KILLS. |
4ee9c684 | 618 | |
e551bd1a | 619 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
5cdd0289 | 620 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
4ee9c684 | 621 | |
e551bd1a | 622 | This information is used to determine which variables are live |
623 | across block boundaries to reduce the number of PHI nodes | |
624 | we create. */ | |
4ee9c684 | 625 | |
e551bd1a | 626 | static void |
6bf320fb | 627 | mark_def_sites (basic_block bb, gimple stmt, bitmap kills) |
e551bd1a | 628 | { |
75a70cf9 | 629 | tree def; |
e551bd1a | 630 | use_operand_p use_p; |
e551bd1a | 631 | ssa_op_iter iter; |
632 | ||
75a70cf9 | 633 | /* Since this is the first time that we rewrite the program into SSA |
634 | form, force an operand scan on every statement. */ | |
75a70cf9 | 635 | update_stmt (stmt); |
e551bd1a | 636 | |
88536563 | 637 | gcc_checking_assert (blocks_to_update == NULL); |
75a70cf9 | 638 | set_register_defs (stmt, false); |
639 | set_rewrite_uses (stmt, false); | |
e551bd1a | 640 | |
9845d120 | 641 | if (is_gimple_debug (stmt)) |
841424cc | 642 | { |
643 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
644 | { | |
645 | tree sym = USE_FROM_PTR (use_p); | |
88536563 | 646 | gcc_checking_assert (DECL_P (sym)); |
841424cc | 647 | set_rewrite_uses (stmt, true); |
648 | } | |
649 | if (rewrite_uses_p (stmt)) | |
08b7917c | 650 | bitmap_set_bit (interesting_blocks, bb->index); |
841424cc | 651 | return; |
652 | } | |
9845d120 | 653 | |
e551bd1a | 654 | /* If a variable is used before being set, then the variable is live |
655 | across a block boundary, so mark it live-on-entry to BB. */ | |
5aabc5f2 | 656 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
e551bd1a | 657 | { |
88dbf20f | 658 | tree sym = USE_FROM_PTR (use_p); |
88536563 | 659 | gcc_checking_assert (DECL_P (sym)); |
a55dc2cd | 660 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
88dbf20f | 661 | set_livein_block (sym, bb); |
75a70cf9 | 662 | set_rewrite_uses (stmt, true); |
e551bd1a | 663 | } |
48e1416a | 664 | |
4fb5e5ca | 665 | /* Now process the defs. Mark BB as the definition block and add |
666 | each def to the set of killed symbols. */ | |
5aabc5f2 | 667 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
e551bd1a | 668 | { |
88536563 | 669 | gcc_checking_assert (DECL_P (def)); |
88dbf20f | 670 | set_def_block (def, bb, false); |
a55dc2cd | 671 | bitmap_set_bit (kills, DECL_UID (def)); |
75a70cf9 | 672 | set_register_defs (stmt, true); |
e551bd1a | 673 | } |
88dbf20f | 674 | |
675 | /* If we found the statement interesting then also mark the block BB | |
676 | as interesting. */ | |
75a70cf9 | 677 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
08b7917c | 678 | bitmap_set_bit (interesting_blocks, bb->index); |
e551bd1a | 679 | } |
680 | ||
f50cf978 | 681 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
682 | in the dfs numbering of the dominance tree. */ | |
683 | ||
684 | struct dom_dfsnum | |
685 | { | |
686 | /* Basic block whose index this entry corresponds to. */ | |
687 | unsigned bb_index; | |
688 | ||
689 | /* The dfs number of this node. */ | |
690 | unsigned dfs_num; | |
691 | }; | |
692 | ||
693 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
694 | for qsort. */ | |
695 | ||
696 | static int | |
697 | cmp_dfsnum (const void *a, const void *b) | |
698 | { | |
45ba1503 | 699 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
700 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f50cf978 | 701 | |
702 | return (int) da->dfs_num - (int) db->dfs_num; | |
703 | } | |
704 | ||
705 | /* Among the intervals starting at the N points specified in DEFS, find | |
706 | the one that contains S, and return its bb_index. */ | |
707 | ||
708 | static unsigned | |
709 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
710 | { | |
711 | unsigned f = 0, t = n, m; | |
712 | ||
713 | while (t > f + 1) | |
714 | { | |
715 | m = (f + t) / 2; | |
716 | if (defs[m].dfs_num <= s) | |
717 | f = m; | |
718 | else | |
719 | t = m; | |
720 | } | |
721 | ||
722 | return defs[f].bb_index; | |
723 | } | |
724 | ||
725 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
726 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
727 | ||
728 | static void | |
729 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
730 | { | |
f1f41a6c | 731 | vec<int> worklist; |
f50cf978 | 732 | bitmap_iterator bi; |
733 | unsigned i, b, p, u, top; | |
734 | bitmap live_phis; | |
735 | basic_block def_bb, use_bb; | |
736 | edge e; | |
737 | edge_iterator ei; | |
738 | bitmap to_remove; | |
739 | struct dom_dfsnum *defs; | |
740 | unsigned n_defs, adef; | |
741 | ||
742 | if (bitmap_empty_p (uses)) | |
743 | { | |
744 | bitmap_clear (phis); | |
745 | return; | |
746 | } | |
747 | ||
748 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
749 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
750 | to_remove = BITMAP_ALLOC (NULL); | |
751 | bitmap_and_compl (to_remove, kills, uses); | |
752 | bitmap_and_compl_into (phis, to_remove); | |
753 | if (bitmap_empty_p (phis)) | |
754 | { | |
755 | BITMAP_FREE (to_remove); | |
756 | return; | |
757 | } | |
758 | ||
759 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
760 | liveness information, as that may be linear in the size of CFG, and if | |
761 | there are lot of different variables to rewrite, this may lead to quadratic | |
762 | behavior. | |
763 | ||
764 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
765 | then for each of them find the nearest def that dominates them. If this | |
766 | def is a phi node, we mark it live, and if it was not live before, we | |
767 | add the predecessors of its basic block to the worklist. | |
48e1416a | 768 | |
f50cf978 | 769 | To quickly locate the nearest def that dominates use, we use dfs numbering |
770 | of the dominance tree (that is already available in order to speed up | |
771 | queries). For each def, we have the interval given by the dfs number on | |
772 | entry to and on exit from the corresponding subtree in the dominance tree. | |
773 | The nearest dominator for a given use is the smallest of these intervals | |
774 | that contains entry and exit dfs numbers for the basic block with the use. | |
775 | If we store the bounds for all the uses to an array and sort it, we can | |
776 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
777 | bitmap_ior (to_remove, kills, phis); | |
778 | n_defs = bitmap_count_bits (to_remove); | |
779 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
780 | defs[0].bb_index = 1; | |
781 | defs[0].dfs_num = 0; | |
782 | adef = 1; | |
783 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
784 | { | |
785 | def_bb = BASIC_BLOCK (i); | |
786 | defs[adef].bb_index = i; | |
787 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
788 | defs[adef + 1].bb_index = i; | |
789 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
790 | adef += 2; | |
791 | } | |
792 | BITMAP_FREE (to_remove); | |
793 | gcc_assert (adef == 2 * n_defs + 1); | |
794 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
795 | gcc_assert (defs[0].bb_index == 1); | |
796 | ||
797 | /* Now each DEFS entry contains the number of the basic block to that the | |
798 | dfs number corresponds. Change them to the number of basic block that | |
799 | corresponds to the interval following the dfs number. Also, for the | |
800 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
801 | to the start of the following interval, not to the end of the current | |
802 | one). We use WORKLIST as a stack. */ | |
f1f41a6c | 803 | worklist.create (n_defs + 1); |
804 | worklist.quick_push (1); | |
f50cf978 | 805 | top = 1; |
806 | n_defs = 1; | |
807 | for (i = 1; i < adef; i++) | |
808 | { | |
809 | b = defs[i].bb_index; | |
810 | if (b == top) | |
811 | { | |
812 | /* This is a closing element. Interval corresponding to the top | |
813 | of the stack after removing it follows. */ | |
f1f41a6c | 814 | worklist.pop (); |
815 | top = worklist[worklist.length () - 1]; | |
f50cf978 | 816 | defs[n_defs].bb_index = top; |
817 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
818 | } | |
819 | else | |
820 | { | |
821 | /* Opening element. Nothing to do, just push it to the stack and move | |
822 | it to the correct position. */ | |
823 | defs[n_defs].bb_index = defs[i].bb_index; | |
824 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
f1f41a6c | 825 | worklist.quick_push (b); |
f50cf978 | 826 | top = b; |
827 | } | |
828 | ||
829 | /* If this interval starts at the same point as the previous one, cancel | |
830 | the previous one. */ | |
831 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
832 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
833 | else | |
834 | n_defs++; | |
835 | } | |
f1f41a6c | 836 | worklist.pop (); |
837 | gcc_assert (worklist.is_empty ()); | |
f50cf978 | 838 | |
839 | /* Now process the uses. */ | |
840 | live_phis = BITMAP_ALLOC (NULL); | |
841 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
842 | { | |
f1f41a6c | 843 | worklist.safe_push (i); |
f50cf978 | 844 | } |
845 | ||
f1f41a6c | 846 | while (!worklist.is_empty ()) |
f50cf978 | 847 | { |
f1f41a6c | 848 | b = worklist.pop (); |
f50cf978 | 849 | if (b == ENTRY_BLOCK) |
850 | continue; | |
851 | ||
852 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
853 | find the def that dominates the immediate dominator of USE_BB | |
854 | (the kill in USE_BB does not dominate the use). */ | |
855 | if (bitmap_bit_p (phis, b)) | |
856 | p = b; | |
857 | else | |
858 | { | |
859 | use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b)); | |
860 | p = find_dfsnum_interval (defs, n_defs, | |
861 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
862 | if (!bitmap_bit_p (phis, p)) | |
863 | continue; | |
864 | } | |
865 | ||
866 | /* If the phi node is already live, there is nothing to do. */ | |
6ef9bbe0 | 867 | if (!bitmap_set_bit (live_phis, p)) |
f50cf978 | 868 | continue; |
869 | ||
6ef9bbe0 | 870 | /* Add the new uses to the worklist. */ |
f50cf978 | 871 | def_bb = BASIC_BLOCK (p); |
872 | FOR_EACH_EDGE (e, ei, def_bb->preds) | |
873 | { | |
874 | u = e->src->index; | |
875 | if (bitmap_bit_p (uses, u)) | |
876 | continue; | |
877 | ||
94858f65 | 878 | /* In case there is a kill directly in the use block, do not record |
879 | the use (this is also necessary for correctness, as we assume that | |
880 | uses dominated by a def directly in their block have been filtered | |
881 | out before). */ | |
882 | if (bitmap_bit_p (kills, u)) | |
883 | continue; | |
884 | ||
f50cf978 | 885 | bitmap_set_bit (uses, u); |
f1f41a6c | 886 | worklist.safe_push (u); |
f50cf978 | 887 | } |
888 | } | |
889 | ||
f1f41a6c | 890 | worklist.release (); |
f50cf978 | 891 | bitmap_copy (phis, live_phis); |
892 | BITMAP_FREE (live_phis); | |
893 | free (defs); | |
894 | } | |
e551bd1a | 895 | |
e551bd1a | 896 | /* Return the set of blocks where variable VAR is defined and the blocks |
897 | where VAR is live on entry (livein). Return NULL, if no entry is | |
898 | found in DEF_BLOCKS. */ | |
899 | ||
900 | static inline struct def_blocks_d * | |
901 | find_def_blocks_for (tree var) | |
902 | { | |
74105c0d | 903 | def_blocks_p p = &get_common_info (var)->def_blocks; |
22d6c74e | 904 | if (!p->def_blocks) |
905 | return NULL; | |
906 | return p; | |
e551bd1a | 907 | } |
908 | ||
909 | ||
70630fcd | 910 | /* Marks phi node PHI in basic block BB for rewrite. */ |
911 | ||
912 | static void | |
75a70cf9 | 913 | mark_phi_for_rewrite (basic_block bb, gimple phi) |
70630fcd | 914 | { |
75a70cf9 | 915 | gimple_vec phis; |
2670407e | 916 | unsigned n, idx = bb->index; |
70630fcd | 917 | |
75a70cf9 | 918 | if (rewrite_uses_p (phi)) |
70630fcd | 919 | return; |
4fb5e5ca | 920 | |
75a70cf9 | 921 | set_rewrite_uses (phi, true); |
70630fcd | 922 | |
923 | if (!blocks_with_phis_to_rewrite) | |
924 | return; | |
925 | ||
926 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
2670407e | 927 | |
928 | n = (unsigned) last_basic_block + 1; | |
f1f41a6c | 929 | if (phis_to_rewrite.length () < n) |
930 | phis_to_rewrite.safe_grow_cleared (n); | |
70630fcd | 931 | |
f1f41a6c | 932 | phis = phis_to_rewrite[idx]; |
933 | phis.reserve (10); | |
70630fcd | 934 | |
f1f41a6c | 935 | phis.safe_push (phi); |
936 | phis_to_rewrite[idx] = phis; | |
70630fcd | 937 | } |
938 | ||
e551bd1a | 939 | /* Insert PHI nodes for variable VAR using the iterated dominance |
88dbf20f | 940 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
4fb5e5ca | 941 | function assumes that the caller is incrementally updating the |
942 | existing SSA form, in which case VAR may be an SSA name instead of | |
943 | a symbol. | |
88dbf20f | 944 | |
945 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
946 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
947 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
e551bd1a | 948 | |
949 | static void | |
88dbf20f | 950 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
e551bd1a | 951 | { |
952 | unsigned bb_index; | |
953 | edge e; | |
75a70cf9 | 954 | gimple phi; |
e551bd1a | 955 | basic_block bb; |
956 | bitmap_iterator bi; | |
88536563 | 957 | struct def_blocks_d *def_map = find_def_blocks_for (var); |
e551bd1a | 958 | |
959 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
960 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
961 | ||
f50cf978 | 962 | /* Remove obviously useless phi nodes. */ |
963 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
964 | def_map->livein_blocks); | |
e551bd1a | 965 | |
966 | /* And insert the PHI nodes. */ | |
f50cf978 | 967 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
e551bd1a | 968 | { |
969 | bb = BASIC_BLOCK (bb_index); | |
2920559d | 970 | if (update_p) |
971 | mark_block_for_update (bb); | |
e551bd1a | 972 | |
75a70cf9 | 973 | phi = NULL; |
4fb5e5ca | 974 | |
975 | if (TREE_CODE (var) == SSA_NAME) | |
e551bd1a | 976 | { |
095dcfa3 | 977 | /* If we are rewriting SSA names, create the LHS of the PHI |
978 | node by duplicating VAR. This is useful in the case of | |
979 | pointers, to also duplicate pointer attributes (alias | |
980 | information, in particular). */ | |
e551bd1a | 981 | edge_iterator ei; |
095dcfa3 | 982 | tree new_lhs; |
88dbf20f | 983 | |
88536563 | 984 | gcc_checking_assert (update_p); |
9c06f260 | 985 | new_lhs = duplicate_ssa_name (var, NULL); |
986 | phi = create_phi_node (new_lhs, bb); | |
095dcfa3 | 987 | add_new_name_mapping (new_lhs, var); |
88dbf20f | 988 | |
989 | /* Add VAR to every argument slot of PHI. We need VAR in | |
990 | every argument so that rewrite_update_phi_arguments knows | |
991 | which name is this PHI node replacing. If VAR is a | |
992 | symbol marked for renaming, this is not necessary, the | |
993 | renamer will use the symbol on the LHS to get its | |
994 | reaching definition. */ | |
e551bd1a | 995 | FOR_EACH_EDGE (e, ei, bb->preds) |
60d535d2 | 996 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
e551bd1a | 997 | } |
095dcfa3 | 998 | else |
999 | { | |
9845d120 | 1000 | tree tracked_var; |
cd610ee6 | 1001 | |
88536563 | 1002 | gcc_checking_assert (DECL_P (var)); |
25ae9ba2 | 1003 | phi = create_phi_node (var, bb); |
cd610ee6 | 1004 | |
1005 | tracked_var = target_for_debug_bind (var); | |
1006 | if (tracked_var) | |
9845d120 | 1007 | { |
1008 | gimple note = gimple_build_debug_bind (tracked_var, | |
1009 | PHI_RESULT (phi), | |
1010 | phi); | |
1011 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1012 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1013 | } | |
095dcfa3 | 1014 | } |
88dbf20f | 1015 | |
1016 | /* Mark this PHI node as interesting for update_ssa. */ | |
75a70cf9 | 1017 | set_register_defs (phi, true); |
70630fcd | 1018 | mark_phi_for_rewrite (bb, phi); |
e551bd1a | 1019 | } |
1020 | } | |
1021 | ||
22d6c74e | 1022 | /* Sort var_infos after DECL_UID of their var. */ |
c86a4051 | 1023 | |
1024 | static int | |
22d6c74e | 1025 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
c86a4051 | 1026 | { |
22d6c74e | 1027 | const struct var_info_d *defa = *(struct var_info_d * const *)a; |
1028 | const struct var_info_d *defb = *(struct var_info_d * const *)b; | |
c86a4051 | 1029 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1030 | return -1; | |
1031 | else | |
1032 | return 1; | |
1033 | } | |
e551bd1a | 1034 | |
e551bd1a | 1035 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1036 | definitions. DFS contains the dominance frontier information for | |
4fb5e5ca | 1037 | the flowgraph. */ |
e551bd1a | 1038 | |
1039 | static void | |
8a2980be | 1040 | insert_phi_nodes (bitmap_head *dfs) |
e551bd1a | 1041 | { |
c86a4051 | 1042 | htab_iterator hi; |
1043 | unsigned i; | |
22d6c74e | 1044 | var_info_p info; |
f1f41a6c | 1045 | vec<var_info_p> vars; |
e551bd1a | 1046 | |
1047 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
48e1416a | 1048 | |
f1f41a6c | 1049 | vars.create (htab_elements (var_infos)); |
22d6c74e | 1050 | FOR_EACH_HTAB_ELEMENT (var_infos, info, var_info_p, hi) |
74105c0d | 1051 | if (info->info.need_phi_state != NEED_PHI_STATE_NO) |
f1f41a6c | 1052 | vars.quick_push (info); |
c86a4051 | 1053 | |
409a375f | 1054 | /* Do two stages to avoid code generation differences for UID |
1055 | differences but no UID ordering differences. */ | |
f1f41a6c | 1056 | vars.qsort (insert_phi_nodes_compare_var_infos); |
409a375f | 1057 | |
f1f41a6c | 1058 | FOR_EACH_VEC_ELT (vars, i, info) |
f3d9a16c | 1059 | { |
74105c0d | 1060 | bitmap idf = compute_idf (info->info.def_blocks.def_blocks, dfs); |
22d6c74e | 1061 | insert_phi_nodes_for (info->var, idf, false); |
409a375f | 1062 | BITMAP_FREE (idf); |
1063 | } | |
1064 | ||
f1f41a6c | 1065 | vars.release (); |
409a375f | 1066 | |
4ee9c684 | 1067 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1068 | } | |
1069 | ||
1070 | ||
4fb5e5ca | 1071 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1072 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
e551bd1a | 1073 | |
de6ed584 | 1074 | static void |
4fb5e5ca | 1075 | register_new_def (tree def, tree sym) |
e551bd1a | 1076 | { |
74105c0d | 1077 | common_info_p info = get_common_info (sym); |
e551bd1a | 1078 | tree currdef; |
48e1416a | 1079 | |
e551bd1a | 1080 | /* If this variable is set in a single basic block and all uses are |
1081 | dominated by the set(s) in that single basic block, then there is | |
1082 | no reason to record anything for this variable in the block local | |
1083 | definition stacks. Doing so just wastes time and memory. | |
1084 | ||
1085 | This is the same test to prune the set of variables which may | |
1086 | need PHI nodes. So we just use that information since it's already | |
1087 | computed and available for us to use. */ | |
74105c0d | 1088 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
e551bd1a | 1089 | { |
74105c0d | 1090 | info->current_def = def; |
e551bd1a | 1091 | return; |
1092 | } | |
1093 | ||
74105c0d | 1094 | currdef = info->current_def; |
e551bd1a | 1095 | |
4fb5e5ca | 1096 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1097 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1098 | in the stack so that we know which symbol is being defined by | |
1099 | this SSA name when we unwind the stack. */ | |
1100 | if (currdef && !is_gimple_reg (sym)) | |
f1f41a6c | 1101 | block_defs_stack.safe_push (sym); |
e551bd1a | 1102 | |
4fb5e5ca | 1103 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1104 | stack is later used by the dominator tree callbacks to restore | |
1105 | the reaching definitions for all the variables defined in the | |
1106 | block after a recursive visit to all its immediately dominated | |
1107 | blocks. If there is no current reaching definition, then just | |
1108 | record the underlying _DECL node. */ | |
f1f41a6c | 1109 | block_defs_stack.safe_push (currdef ? currdef : sym); |
4fb5e5ca | 1110 | |
1111 | /* Set the current reaching definition for SYM to be DEF. */ | |
74105c0d | 1112 | info->current_def = def; |
e551bd1a | 1113 | } |
1114 | ||
1115 | ||
4ee9c684 | 1116 | /* Perform a depth-first traversal of the dominator tree looking for |
1117 | variables to rename. BB is the block where to start searching. | |
1118 | Renaming is a five step process: | |
1119 | ||
1120 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1121 | registered as the current definition for the corresponding variable. | |
1122 | ||
1123 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1124 | rewritten with their corresponding reaching definition. DEF and | |
1125 | VDEF targets are registered as new definitions. | |
48e1416a | 1126 | |
4ee9c684 | 1127 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1128 | argument corresponding to BB is replaced with its current reaching | |
1129 | definition. | |
1130 | ||
1131 | 4- Recursively rewrite every dominator child block of BB. | |
1132 | ||
1133 | 5- Restore (in reverse order) the current reaching definition for every | |
1134 | new definition introduced in this block. This is done so that when | |
1135 | we return from the recursive call, all the current reaching | |
1136 | definitions are restored to the names that were valid in the | |
1137 | dominator parent of BB. */ | |
1138 | ||
e551bd1a | 1139 | /* Return the current definition for variable VAR. If none is found, |
4fb5e5ca | 1140 | create a new SSA name to act as the zeroth definition for VAR. */ |
f3d9a16c | 1141 | |
e551bd1a | 1142 | static tree |
1143 | get_reaching_def (tree var) | |
1144 | { | |
74105c0d | 1145 | common_info_p info = get_common_info (var); |
4fb5e5ca | 1146 | tree currdef; |
48e1416a | 1147 | |
e551bd1a | 1148 | /* Lookup the current reaching definition for VAR. */ |
74105c0d | 1149 | currdef = info->current_def; |
f3d9a16c | 1150 | |
e551bd1a | 1151 | /* If there is no reaching definition for VAR, create and register a |
1152 | default definition for it (if needed). */ | |
4fb5e5ca | 1153 | if (currdef == NULL_TREE) |
e551bd1a | 1154 | { |
4fb5e5ca | 1155 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
c6dfe037 | 1156 | currdef = get_or_create_ssa_default_def (cfun, sym); |
e551bd1a | 1157 | } |
1158 | ||
1159 | /* Return the current reaching definition for VAR, or the default | |
1160 | definition, if we had to create one. */ | |
4fb5e5ca | 1161 | return currdef; |
e551bd1a | 1162 | } |
1163 | ||
1164 | ||
841424cc | 1165 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1166 | ||
1167 | static void | |
1168 | rewrite_debug_stmt_uses (gimple stmt) | |
1169 | { | |
1170 | use_operand_p use_p; | |
1171 | ssa_op_iter iter; | |
1172 | bool update = false; | |
1173 | ||
1174 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1175 | { | |
4ae5778c | 1176 | tree var = USE_FROM_PTR (use_p), def; |
74105c0d | 1177 | common_info_p info = get_common_info (var); |
88536563 | 1178 | gcc_checking_assert (DECL_P (var)); |
74105c0d | 1179 | def = info->current_def; |
4ae5778c | 1180 | if (!def) |
841424cc | 1181 | { |
1182 | if (TREE_CODE (var) == PARM_DECL && single_succ_p (ENTRY_BLOCK_PTR)) | |
1183 | { | |
1184 | gimple_stmt_iterator gsi | |
1185 | = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1186 | int lim; | |
1187 | /* Search a few source bind stmts at the start of first bb to | |
1188 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1189 | for (lim = 32; | |
1190 | !gsi_end_p (gsi) && lim > 0; | |
1191 | gsi_next (&gsi), lim--) | |
1192 | { | |
1193 | gimple gstmt = gsi_stmt (gsi); | |
1194 | if (!gimple_debug_source_bind_p (gstmt)) | |
1195 | break; | |
1196 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1197 | { | |
1198 | def = gimple_debug_source_bind_get_var (gstmt); | |
1199 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1200 | break; | |
1201 | else | |
1202 | def = NULL_TREE; | |
1203 | } | |
1204 | } | |
1205 | /* If not, add a new source bind stmt. */ | |
1206 | if (def == NULL_TREE) | |
1207 | { | |
1208 | gimple def_temp; | |
1209 | def = make_node (DEBUG_EXPR_DECL); | |
1210 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1211 | DECL_ARTIFICIAL (def) = 1; | |
1212 | TREE_TYPE (def) = TREE_TYPE (var); | |
1213 | DECL_MODE (def) = DECL_MODE (var); | |
1214 | gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1215 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); | |
1216 | } | |
1217 | update = true; | |
1218 | } | |
1219 | } | |
1220 | else | |
824651eb | 1221 | { |
74105c0d | 1222 | /* Check if info->current_def can be trusted. */ |
4ae5778c | 1223 | basic_block bb = gimple_bb (stmt); |
1224 | basic_block def_bb | |
1225 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1226 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1227 | ||
1228 | /* If definition is in current bb, it is fine. */ | |
1229 | if (bb == def_bb) | |
1230 | ; | |
1231 | /* If definition bb doesn't dominate the current bb, | |
1232 | it can't be used. */ | |
1233 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1234 | def = NULL; | |
1235 | /* If there is just one definition and dominates the current | |
1236 | bb, it is fine. */ | |
74105c0d | 1237 | else if (info->need_phi_state == NEED_PHI_STATE_NO) |
4ae5778c | 1238 | ; |
1239 | else | |
824651eb | 1240 | { |
74105c0d | 1241 | struct def_blocks_d *db_p = get_def_blocks_for (info); |
824651eb | 1242 | |
4ae5778c | 1243 | /* If there are some non-debug uses in the current bb, |
1244 | it is fine. */ | |
1245 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
824651eb | 1246 | ; |
4ae5778c | 1247 | /* Otherwise give up for now. */ |
824651eb | 1248 | else |
4ae5778c | 1249 | def = NULL; |
824651eb | 1250 | } |
1251 | } | |
841424cc | 1252 | if (def == NULL) |
1253 | { | |
1254 | gimple_debug_bind_reset_value (stmt); | |
1255 | update_stmt (stmt); | |
1256 | return; | |
1257 | } | |
1258 | SET_USE (use_p, def); | |
1259 | } | |
1260 | if (update) | |
1261 | update_stmt (stmt); | |
1262 | } | |
1263 | ||
e551bd1a | 1264 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1265 | the block with its immediate reaching definitions. Update the current | |
1266 | definition of a variable when a new real or virtual definition is found. */ | |
f3d9a16c | 1267 | |
1268 | static void | |
eb54054d | 1269 | rewrite_stmt (gimple_stmt_iterator *si) |
f3d9a16c | 1270 | { |
e551bd1a | 1271 | use_operand_p use_p; |
1272 | def_operand_p def_p; | |
1273 | ssa_op_iter iter; | |
eb54054d | 1274 | gimple stmt = gsi_stmt (*si); |
e551bd1a | 1275 | |
e551bd1a | 1276 | /* If mark_def_sites decided that we don't need to rewrite this |
1277 | statement, ignore it. */ | |
2920559d | 1278 | gcc_assert (blocks_to_update == NULL); |
75a70cf9 | 1279 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
e551bd1a | 1280 | return; |
f3d9a16c | 1281 | |
1282 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
e551bd1a | 1283 | { |
1284 | fprintf (dump_file, "Renaming statement "); | |
75a70cf9 | 1285 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
e551bd1a | 1286 | fprintf (dump_file, "\n"); |
1287 | } | |
f3d9a16c | 1288 | |
4fb5e5ca | 1289 | /* Step 1. Rewrite USES in the statement. */ |
75a70cf9 | 1290 | if (rewrite_uses_p (stmt)) |
841424cc | 1291 | { |
1292 | if (is_gimple_debug (stmt)) | |
1293 | rewrite_debug_stmt_uses (stmt); | |
1294 | else | |
5aabc5f2 | 1295 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
841424cc | 1296 | { |
1297 | tree var = USE_FROM_PTR (use_p); | |
88536563 | 1298 | gcc_checking_assert (DECL_P (var)); |
841424cc | 1299 | SET_USE (use_p, get_reaching_def (var)); |
1300 | } | |
1301 | } | |
f3d9a16c | 1302 | |
4fb5e5ca | 1303 | /* Step 2. Register the statement's DEF operands. */ |
75a70cf9 | 1304 | if (register_defs_p (stmt)) |
5aabc5f2 | 1305 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
88dbf20f | 1306 | { |
1307 | tree var = DEF_FROM_PTR (def_p); | |
eb54054d | 1308 | tree name; |
9845d120 | 1309 | tree tracked_var; |
eb54054d | 1310 | |
88536563 | 1311 | gcc_checking_assert (DECL_P (var)); |
eb54054d | 1312 | |
1313 | if (gimple_clobber_p (stmt) | |
1314 | && is_gimple_reg (var)) | |
1315 | { | |
1316 | /* If we rewrite a DECL into SSA form then drop its | |
1317 | clobber stmts and replace uses with a new default def. */ | |
88536563 | 1318 | gcc_checking_assert (TREE_CODE (var) == VAR_DECL |
1319 | && !gimple_vdef (stmt)); | |
eb54054d | 1320 | gsi_replace (si, gimple_build_nop (), true); |
1321 | register_new_def (get_or_create_ssa_default_def (cfun, var), var); | |
1322 | break; | |
1323 | } | |
1324 | ||
1325 | name = make_ssa_name (var, stmt); | |
9845d120 | 1326 | SET_DEF (def_p, name); |
4fb5e5ca | 1327 | register_new_def (DEF_FROM_PTR (def_p), var); |
9845d120 | 1328 | |
1329 | tracked_var = target_for_debug_bind (var); | |
1330 | if (tracked_var) | |
1331 | { | |
1332 | gimple note = gimple_build_debug_bind (tracked_var, name, stmt); | |
eb54054d | 1333 | gsi_insert_after (si, note, GSI_SAME_STMT); |
9845d120 | 1334 | } |
88dbf20f | 1335 | } |
f3d9a16c | 1336 | } |
4ee9c684 | 1337 | |
e551bd1a | 1338 | |
4ee9c684 | 1339 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1340 | PHI nodes. For every PHI node found, add a new argument containing the | |
1341 | current reaching definition for the variable and the edge through which | |
dac49aa5 | 1342 | that definition is reaching the PHI node. */ |
4ee9c684 | 1343 | |
1344 | static void | |
6bf320fb | 1345 | rewrite_add_phi_arguments (basic_block bb) |
4ee9c684 | 1346 | { |
1347 | edge e; | |
cd665a06 | 1348 | edge_iterator ei; |
4ee9c684 | 1349 | |
cd665a06 | 1350 | FOR_EACH_EDGE (e, ei, bb->succs) |
4ee9c684 | 1351 | { |
75a70cf9 | 1352 | gimple phi; |
1353 | gimple_stmt_iterator gsi; | |
4ee9c684 | 1354 | |
75a70cf9 | 1355 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1356 | gsi_next (&gsi)) | |
4ee9c684 | 1357 | { |
1358 | tree currdef; | |
efbcb6de | 1359 | gimple stmt; |
1360 | ||
75a70cf9 | 1361 | phi = gsi_stmt (gsi); |
1362 | currdef = get_reaching_def (SSA_NAME_VAR (gimple_phi_result (phi))); | |
efbcb6de | 1363 | stmt = SSA_NAME_DEF_STMT (currdef); |
60d535d2 | 1364 | add_phi_arg (phi, currdef, e, gimple_location (stmt)); |
4ee9c684 | 1365 | } |
1366 | } | |
1367 | } | |
1368 | ||
6bf320fb | 1369 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1370 | of reaching definitions for new SSA names produced in this block | |
1371 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1372 | block. */ | |
1373 | ||
1374 | static void | |
1375 | rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1376 | basic_block bb) | |
1377 | { | |
6bf320fb | 1378 | gimple_stmt_iterator gsi; |
1379 | ||
1380 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1381 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1382 | ||
1383 | /* Mark the unwind point for this block. */ | |
f1f41a6c | 1384 | block_defs_stack.safe_push (NULL_TREE); |
6bf320fb | 1385 | |
1386 | /* Step 1. Register new definitions for every PHI node in the block. | |
1387 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1388 | node introduces a new version for the associated variable. */ | |
1389 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1390 | { | |
5aabc5f2 | 1391 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
6bf320fb | 1392 | register_new_def (result, SSA_NAME_VAR (result)); |
1393 | } | |
1394 | ||
1395 | /* Step 2. Rewrite every variable used in each statement in the block | |
1396 | with its immediate reaching definitions. Update the current definition | |
1397 | of a variable when a new real or virtual definition is found. */ | |
08b7917c | 1398 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
6bf320fb | 1399 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
eb54054d | 1400 | rewrite_stmt (&gsi); |
6bf320fb | 1401 | |
1402 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1403 | For every PHI node found, add a new argument containing the current | |
1404 | reaching definition for the variable and the edge through which that | |
1405 | definition is reaching the PHI node. */ | |
1406 | rewrite_add_phi_arguments (bb); | |
1407 | } | |
1408 | ||
1409 | ||
e551bd1a | 1410 | |
4fb5e5ca | 1411 | /* Called after visiting all the statements in basic block BB and all |
1412 | of its dominator children. Restore CURRDEFS to its original value. */ | |
4ee9c684 | 1413 | |
1414 | static void | |
6bf320fb | 1415 | rewrite_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1416 | basic_block bb ATTRIBUTE_UNUSED) | |
4ee9c684 | 1417 | { |
dd2d357d | 1418 | /* Restore CURRDEFS to its original state. */ |
f1f41a6c | 1419 | while (block_defs_stack.length () > 0) |
4ee9c684 | 1420 | { |
f1f41a6c | 1421 | tree tmp = block_defs_stack.pop (); |
4ee9c684 | 1422 | tree saved_def, var; |
1423 | ||
dd2d357d | 1424 | if (tmp == NULL_TREE) |
1425 | break; | |
1426 | ||
4ee9c684 | 1427 | if (TREE_CODE (tmp) == SSA_NAME) |
1428 | { | |
4fb5e5ca | 1429 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1430 | current definition of its underlying variable. Note that | |
1431 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1432 | being defined is stored in the next slot in the stack. | |
1433 | This mechanism is needed because an SSA name for a | |
1434 | non-register symbol may be the definition for more than | |
1435 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
4ee9c684 | 1436 | saved_def = tmp; |
1437 | var = SSA_NAME_VAR (saved_def); | |
4fb5e5ca | 1438 | if (!is_gimple_reg (var)) |
f1f41a6c | 1439 | var = block_defs_stack.pop (); |
4ee9c684 | 1440 | } |
1441 | else | |
1442 | { | |
4fb5e5ca | 1443 | /* If we recorded anything else, it must have been a _DECL |
1444 | node and its current reaching definition must have been | |
1445 | NULL. */ | |
4ee9c684 | 1446 | saved_def = NULL; |
1447 | var = tmp; | |
1448 | } | |
48e1416a | 1449 | |
74105c0d | 1450 | get_common_info (var)->current_def = saved_def; |
4ee9c684 | 1451 | } |
1452 | } | |
1453 | ||
1454 | ||
4fb5e5ca | 1455 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1456 | ||
1457 | void | |
1458 | dump_decl_set (FILE *file, bitmap set) | |
1459 | { | |
1460 | if (set) | |
1461 | { | |
c0ff55b3 | 1462 | bitmap_iterator bi; |
1463 | unsigned i; | |
4fb5e5ca | 1464 | |
1465 | fprintf (file, "{ "); | |
1466 | ||
c0ff55b3 | 1467 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
4fb5e5ca | 1468 | { |
b03e5397 | 1469 | fprintf (file, "D.%u", i); |
4fb5e5ca | 1470 | fprintf (file, " "); |
1471 | } | |
1472 | ||
dd277d48 | 1473 | fprintf (file, "}"); |
4fb5e5ca | 1474 | } |
1475 | else | |
dd277d48 | 1476 | fprintf (file, "NIL"); |
4fb5e5ca | 1477 | } |
1478 | ||
1479 | ||
1480 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ | |
1481 | ||
4b987fac | 1482 | DEBUG_FUNCTION void |
4fb5e5ca | 1483 | debug_decl_set (bitmap set) |
1484 | { | |
1485 | dump_decl_set (stderr, set); | |
dd277d48 | 1486 | fprintf (stderr, "\n"); |
4fb5e5ca | 1487 | } |
1488 | ||
1489 | ||
1490 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1491 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1492 | dumped. New levels are created when the dominator tree traversal | |
1493 | used for renaming enters a new sub-tree. */ | |
1494 | ||
1495 | void | |
1496 | dump_defs_stack (FILE *file, int n) | |
1497 | { | |
1498 | int i, j; | |
1499 | ||
1500 | fprintf (file, "\n\nRenaming stack"); | |
1501 | if (n > 0) | |
1502 | fprintf (file, " (up to %d levels)", n); | |
1503 | fprintf (file, "\n\n"); | |
1504 | ||
1505 | i = 1; | |
1506 | fprintf (file, "Level %d (current level)\n", i); | |
f1f41a6c | 1507 | for (j = (int) block_defs_stack.length () - 1; j >= 0; j--) |
4fb5e5ca | 1508 | { |
1509 | tree name, var; | |
48e1416a | 1510 | |
f1f41a6c | 1511 | name = block_defs_stack[j]; |
4fb5e5ca | 1512 | if (name == NULL_TREE) |
1513 | { | |
1514 | i++; | |
1515 | if (n > 0 && i > n) | |
1516 | break; | |
1517 | fprintf (file, "\nLevel %d\n", i); | |
1518 | continue; | |
1519 | } | |
1520 | ||
1521 | if (DECL_P (name)) | |
1522 | { | |
1523 | var = name; | |
1524 | name = NULL_TREE; | |
1525 | } | |
1526 | else | |
1527 | { | |
1528 | var = SSA_NAME_VAR (name); | |
1529 | if (!is_gimple_reg (var)) | |
1530 | { | |
1531 | j--; | |
f1f41a6c | 1532 | var = block_defs_stack[j]; |
4fb5e5ca | 1533 | } |
1534 | } | |
1535 | ||
1536 | fprintf (file, " Previous CURRDEF ("); | |
1537 | print_generic_expr (file, var, 0); | |
1538 | fprintf (file, ") = "); | |
1539 | if (name) | |
1540 | print_generic_expr (file, name, 0); | |
1541 | else | |
1542 | fprintf (file, "<NIL>"); | |
1543 | fprintf (file, "\n"); | |
1544 | } | |
1545 | } | |
1546 | ||
1547 | ||
1548 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1549 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1550 | dumped. New levels are created when the dominator tree traversal | |
1551 | used for renaming enters a new sub-tree. */ | |
1552 | ||
4b987fac | 1553 | DEBUG_FUNCTION void |
4fb5e5ca | 1554 | debug_defs_stack (int n) |
1555 | { | |
1556 | dump_defs_stack (stderr, n); | |
1557 | } | |
1558 | ||
1559 | ||
1560 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1561 | ||
1562 | void | |
1563 | dump_currdefs (FILE *file) | |
1564 | { | |
e70e8b13 | 1565 | unsigned i; |
4fb5e5ca | 1566 | tree var; |
1567 | ||
f1f41a6c | 1568 | if (symbols_to_rename.is_empty ()) |
e70e8b13 | 1569 | return; |
1570 | ||
4fb5e5ca | 1571 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
f1f41a6c | 1572 | FOR_EACH_VEC_ELT (symbols_to_rename, i, var) |
e70e8b13 | 1573 | { |
74105c0d | 1574 | common_info_p info = get_common_info (var); |
e70e8b13 | 1575 | fprintf (file, "CURRDEF ("); |
1576 | print_generic_expr (file, var, 0); | |
1577 | fprintf (file, ") = "); | |
74105c0d | 1578 | if (info->current_def) |
1579 | print_generic_expr (file, info->current_def, 0); | |
e70e8b13 | 1580 | else |
1581 | fprintf (file, "<NIL>"); | |
1582 | fprintf (file, "\n"); | |
1583 | } | |
4fb5e5ca | 1584 | } |
1585 | ||
1586 | ||
1587 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1588 | ||
4b987fac | 1589 | DEBUG_FUNCTION void |
4fb5e5ca | 1590 | debug_currdefs (void) |
1591 | { | |
1592 | dump_currdefs (stderr); | |
1593 | } | |
1594 | ||
1595 | ||
4ee9c684 | 1596 | /* Dump SSA information to FILE. */ |
1597 | ||
1598 | void | |
1599 | dump_tree_ssa (FILE *file) | |
1600 | { | |
4ee9c684 | 1601 | const char *funcname |
5135beeb | 1602 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
4ee9c684 | 1603 | |
4fb5e5ca | 1604 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
4ee9c684 | 1605 | |
22d6c74e | 1606 | dump_var_infos (file); |
4fb5e5ca | 1607 | dump_defs_stack (file, -1); |
1608 | dump_currdefs (file); | |
1609 | dump_tree_ssa_stats (file); | |
4ee9c684 | 1610 | } |
1611 | ||
1612 | ||
1613 | /* Dump SSA information to stderr. */ | |
1614 | ||
4b987fac | 1615 | DEBUG_FUNCTION void |
4ee9c684 | 1616 | debug_tree_ssa (void) |
1617 | { | |
1618 | dump_tree_ssa (stderr); | |
1619 | } | |
1620 | ||
1621 | ||
e551bd1a | 1622 | /* Dump statistics for the hash table HTAB. */ |
1623 | ||
1624 | static void | |
1625 | htab_statistics (FILE *file, htab_t htab) | |
1626 | { | |
1627 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1628 | (long) htab_size (htab), | |
1629 | (long) htab_elements (htab), | |
1630 | htab_collisions (htab)); | |
1631 | } | |
1632 | ||
1633 | ||
4ee9c684 | 1634 | /* Dump SSA statistics on FILE. */ |
1635 | ||
1636 | void | |
1637 | dump_tree_ssa_stats (FILE *file) | |
1638 | { | |
22d6c74e | 1639 | if (var_infos) |
4fb5e5ca | 1640 | { |
22d6c74e | 1641 | fprintf (file, "\nHash table statistics:\n"); |
1642 | fprintf (file, " var_infos: "); | |
1643 | htab_statistics (file, var_infos); | |
1644 | fprintf (file, "\n"); | |
4fb5e5ca | 1645 | } |
4ee9c684 | 1646 | } |
1647 | ||
1648 | ||
1649 | /* Dump SSA statistics on stderr. */ | |
1650 | ||
4b987fac | 1651 | DEBUG_FUNCTION void |
4ee9c684 | 1652 | debug_tree_ssa_stats (void) |
1653 | { | |
1654 | dump_tree_ssa_stats (stderr); | |
1655 | } | |
1656 | ||
1657 | ||
22d6c74e | 1658 | /* Hashing and equality functions for VAR_INFOS. */ |
4ee9c684 | 1659 | |
e551bd1a | 1660 | static hashval_t |
22d6c74e | 1661 | var_info_hash (const void *p) |
4ee9c684 | 1662 | { |
22d6c74e | 1663 | return DECL_UID (((const struct var_info_d *)p)->var); |
e551bd1a | 1664 | } |
1665 | ||
1666 | static int | |
22d6c74e | 1667 | var_info_eq (const void *p1, const void *p2) |
4ee9c684 | 1668 | { |
22d6c74e | 1669 | return ((const struct var_info_d *)p1)->var |
1670 | == ((const struct var_info_d *)p2)->var; | |
e551bd1a | 1671 | } |
4ee9c684 | 1672 | |
4ee9c684 | 1673 | |
22d6c74e | 1674 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
4ee9c684 | 1675 | |
e551bd1a | 1676 | static int |
22d6c74e | 1677 | debug_var_infos_r (void **slot, void *data) |
e551bd1a | 1678 | { |
4fb5e5ca | 1679 | FILE *file = (FILE *) data; |
74105c0d | 1680 | struct var_info_d *info = (struct var_info_d *) *slot; |
48e1416a | 1681 | |
4fb5e5ca | 1682 | fprintf (file, "VAR: "); |
74105c0d | 1683 | print_generic_expr (file, info->var, dump_flags); |
1684 | bitmap_print (file, info->info.def_blocks.def_blocks, | |
1685 | ", DEF_BLOCKS: { ", "}"); | |
1686 | bitmap_print (file, info->info.def_blocks.livein_blocks, | |
1687 | ", LIVEIN_BLOCKS: { ", "}"); | |
1688 | bitmap_print (file, info->info.def_blocks.phi_blocks, | |
1689 | ", PHI_BLOCKS: { ", "}\n"); | |
4ee9c684 | 1690 | |
e551bd1a | 1691 | return 1; |
1692 | } | |
4ee9c684 | 1693 | |
4ee9c684 | 1694 | |
22d6c74e | 1695 | /* Dump the VAR_INFOS hash table on FILE. */ |
4fb5e5ca | 1696 | |
1697 | void | |
22d6c74e | 1698 | dump_var_infos (FILE *file) |
4fb5e5ca | 1699 | { |
1700 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
22d6c74e | 1701 | if (var_infos) |
1702 | htab_traverse (var_infos, debug_var_infos_r, file); | |
4fb5e5ca | 1703 | } |
1704 | ||
1705 | ||
22d6c74e | 1706 | /* Dump the VAR_INFOS hash table on stderr. */ |
4ee9c684 | 1707 | |
4b987fac | 1708 | DEBUG_FUNCTION void |
22d6c74e | 1709 | debug_var_infos (void) |
e551bd1a | 1710 | { |
22d6c74e | 1711 | dump_var_infos (stderr); |
e551bd1a | 1712 | } |
4ee9c684 | 1713 | |
f3d9a16c | 1714 | |
88dbf20f | 1715 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
4ee9c684 | 1716 | |
88dbf20f | 1717 | static inline void |
1718 | register_new_update_single (tree new_name, tree old_name) | |
1719 | { | |
74105c0d | 1720 | common_info_p info = get_common_info (old_name); |
1721 | tree currdef = info->current_def; | |
f3d9a16c | 1722 | |
4fb5e5ca | 1723 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
88dbf20f | 1724 | This stack is later used by the dominator tree callbacks to |
1725 | restore the reaching definitions for all the variables | |
1726 | defined in the block after a recursive visit to all its | |
1727 | immediately dominated blocks. */ | |
f1f41a6c | 1728 | block_defs_stack.reserve (2); |
1729 | block_defs_stack.quick_push (currdef); | |
1730 | block_defs_stack.quick_push (old_name); | |
f3d9a16c | 1731 | |
88dbf20f | 1732 | /* Set the current reaching definition for OLD_NAME to be |
1733 | NEW_NAME. */ | |
74105c0d | 1734 | info->current_def = new_name; |
88dbf20f | 1735 | } |
e551bd1a | 1736 | |
4ee9c684 | 1737 | |
88dbf20f | 1738 | /* Register NEW_NAME to be the new reaching definition for all the |
1739 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1740 | replace old SSA names with new ones. */ | |
e551bd1a | 1741 | |
88dbf20f | 1742 | static inline void |
1743 | register_new_update_set (tree new_name, bitmap old_names) | |
1744 | { | |
1745 | bitmap_iterator bi; | |
1746 | unsigned i; | |
e551bd1a | 1747 | |
88dbf20f | 1748 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1749 | register_new_update_single (new_name, ssa_name (i)); | |
4ee9c684 | 1750 | } |
1751 | ||
e551bd1a | 1752 | |
88dbf20f | 1753 | |
095dcfa3 | 1754 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1755 | it is a symbol marked for renaming, replace it with USE_P's current | |
1756 | reaching definition. */ | |
1757 | ||
1758 | static inline void | |
1759 | maybe_replace_use (use_operand_p use_p) | |
1760 | { | |
1761 | tree rdef = NULL_TREE; | |
1762 | tree use = USE_FROM_PTR (use_p); | |
1763 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1764 | ||
e70e8b13 | 1765 | if (marked_for_renaming (sym)) |
095dcfa3 | 1766 | rdef = get_reaching_def (sym); |
1767 | else if (is_old_name (use)) | |
1768 | rdef = get_reaching_def (use); | |
1769 | ||
1770 | if (rdef && rdef != use) | |
1771 | SET_USE (use_p, rdef); | |
1772 | } | |
1773 | ||
1774 | ||
9845d120 | 1775 | /* Same as maybe_replace_use, but without introducing default stmts, |
1776 | returning false to indicate a need to do so. */ | |
1777 | ||
1778 | static inline bool | |
1779 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1780 | { | |
1781 | tree rdef = NULL_TREE; | |
1782 | tree use = USE_FROM_PTR (use_p); | |
1783 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1784 | ||
e70e8b13 | 1785 | if (marked_for_renaming (sym)) |
74105c0d | 1786 | rdef = get_var_info (sym)->info.current_def; |
9845d120 | 1787 | else if (is_old_name (use)) |
1788 | { | |
74105c0d | 1789 | rdef = get_ssa_name_ann (use)->info.current_def; |
9845d120 | 1790 | /* We can't assume that, if there's no current definition, the |
1791 | default one should be used. It could be the case that we've | |
1792 | rearranged blocks so that the earlier definition no longer | |
1793 | dominates the use. */ | |
1794 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1795 | rdef = use; | |
1796 | } | |
1797 | else | |
1798 | rdef = use; | |
1799 | ||
1800 | if (rdef && rdef != use) | |
1801 | SET_USE (use_p, rdef); | |
1802 | ||
1803 | return rdef != NULL_TREE; | |
1804 | } | |
1805 | ||
1806 | ||
095dcfa3 | 1807 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1808 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1809 | register it as the current definition for the names replaced by | |
1810 | DEF_P. */ | |
1811 | ||
1812 | static inline void | |
cd610ee6 | 1813 | maybe_register_def (def_operand_p def_p, gimple stmt, |
1814 | gimple_stmt_iterator gsi) | |
095dcfa3 | 1815 | { |
1816 | tree def = DEF_FROM_PTR (def_p); | |
1817 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
1818 | ||
4fb5e5ca | 1819 | /* If DEF is a naked symbol that needs renaming, create a new |
1820 | name for it. */ | |
e70e8b13 | 1821 | if (marked_for_renaming (sym)) |
095dcfa3 | 1822 | { |
1823 | if (DECL_P (def)) | |
1824 | { | |
cd610ee6 | 1825 | tree tracked_var; |
1826 | ||
095dcfa3 | 1827 | def = make_ssa_name (def, stmt); |
1828 | SET_DEF (def_p, def); | |
cd610ee6 | 1829 | |
1830 | tracked_var = target_for_debug_bind (sym); | |
1831 | if (tracked_var) | |
1832 | { | |
1833 | gimple note = gimple_build_debug_bind (tracked_var, def, stmt); | |
8d7f27c3 | 1834 | /* If stmt ends the bb, insert the debug stmt on the single |
1835 | non-EH edge from the stmt. */ | |
1836 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1837 | { | |
1838 | basic_block bb = gsi_bb (gsi); | |
1839 | edge_iterator ei; | |
1840 | edge e, ef = NULL; | |
1841 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1842 | if (!(e->flags & EDGE_EH)) | |
1843 | { | |
88536563 | 1844 | gcc_checking_assert (!ef); |
8d7f27c3 | 1845 | ef = e; |
1846 | } | |
36a2709b | 1847 | /* If there are other predecessors to ef->dest, then |
1848 | there must be PHI nodes for the modified | |
1849 | variable, and therefore there will be debug bind | |
1850 | stmts after the PHI nodes. The debug bind notes | |
1851 | we'd insert would force the creation of a new | |
1852 | block (diverging codegen) and be redundant with | |
1853 | the post-PHI bind stmts, so don't add them. | |
1854 | ||
1855 | As for the exit edge, there wouldn't be redundant | |
1856 | bind stmts, but there wouldn't be a PC to bind | |
1857 | them to either, so avoid diverging the CFG. */ | |
1858 | if (ef && single_pred_p (ef->dest) | |
1859 | && ef->dest != EXIT_BLOCK_PTR) | |
1860 | { | |
1861 | /* If there were PHI nodes in the node, we'd | |
1862 | have to make sure the value we're binding | |
1863 | doesn't need rewriting. But there shouldn't | |
1864 | be PHI nodes in a single-predecessor block, | |
1865 | so we just add the note. */ | |
1866 | gsi_insert_on_edge_immediate (ef, note); | |
1867 | } | |
8d7f27c3 | 1868 | } |
1869 | else | |
1870 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
cd610ee6 | 1871 | } |
095dcfa3 | 1872 | } |
1873 | ||
1874 | register_new_update_single (def, sym); | |
1875 | } | |
1876 | else | |
1877 | { | |
1878 | /* If DEF is a new name, register it as a new definition | |
1879 | for all the names replaced by DEF. */ | |
1880 | if (is_new_name (def)) | |
1881 | register_new_update_set (def, names_replaced_by (def)); | |
1882 | ||
1883 | /* If DEF is an old name, register DEF as a new | |
1884 | definition for itself. */ | |
1885 | if (is_old_name (def)) | |
1886 | register_new_update_single (def, def); | |
1887 | } | |
1888 | } | |
1889 | ||
1890 | ||
88dbf20f | 1891 | /* Update every variable used in the statement pointed-to by SI. The |
1892 | statement is assumed to be in SSA form already. Names in | |
1893 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1894 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1895 | will be registered as a new definition for their corresponding name | |
1896 | in OLD_SSA_NAMES. */ | |
1897 | ||
1898 | static void | |
cd610ee6 | 1899 | rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi) |
88dbf20f | 1900 | { |
88dbf20f | 1901 | use_operand_p use_p; |
1902 | def_operand_p def_p; | |
1903 | ssa_op_iter iter; | |
1904 | ||
88dbf20f | 1905 | /* Only update marked statements. */ |
75a70cf9 | 1906 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
88dbf20f | 1907 | return; |
1908 | ||
1909 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1910 | { | |
1911 | fprintf (dump_file, "Updating SSA information for statement "); | |
75a70cf9 | 1912 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
88dbf20f | 1913 | } |
1914 | ||
1915 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1916 | symbol is marked for renaming. */ | |
75a70cf9 | 1917 | if (rewrite_uses_p (stmt)) |
9845d120 | 1918 | { |
1919 | if (is_gimple_debug (stmt)) | |
1920 | { | |
1921 | bool failed = false; | |
1922 | ||
1923 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1924 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
1925 | { | |
1926 | failed = true; | |
1927 | break; | |
1928 | } | |
1929 | ||
1930 | if (failed) | |
1931 | { | |
1932 | /* DOM sometimes threads jumps in such a way that a | |
1933 | debug stmt ends up referencing a SSA variable that no | |
1934 | longer dominates the debug stmt, but such that all | |
1935 | incoming definitions refer to the same definition in | |
1936 | an earlier dominator. We could try to recover that | |
1937 | definition somehow, but this will have to do for now. | |
1938 | ||
1939 | Introducing a default definition, which is what | |
1940 | maybe_replace_use() would do in such cases, may | |
1941 | modify code generation, for the otherwise-unused | |
1942 | default definition would never go away, modifying SSA | |
1943 | version numbers all over. */ | |
1944 | gimple_debug_bind_reset_value (stmt); | |
1945 | update_stmt (stmt); | |
1946 | } | |
1947 | } | |
1948 | else | |
1949 | { | |
1950 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
1951 | maybe_replace_use (use_p); | |
1952 | } | |
1953 | } | |
88dbf20f | 1954 | |
1955 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
1956 | Also register definitions for names whose underlying symbol is | |
1957 | marked for renaming. */ | |
75a70cf9 | 1958 | if (register_defs_p (stmt)) |
dd277d48 | 1959 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
cd610ee6 | 1960 | maybe_register_def (def_p, stmt, gsi); |
88dbf20f | 1961 | } |
1962 | ||
1963 | ||
1964 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
1965 | every PHI node found, check if any of its arguments is in | |
1966 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
1967 | definition, replace it. */ | |
1968 | ||
1969 | static void | |
6bf320fb | 1970 | rewrite_update_phi_arguments (basic_block bb) |
88dbf20f | 1971 | { |
1972 | edge e; | |
1973 | edge_iterator ei; | |
70630fcd | 1974 | unsigned i; |
88dbf20f | 1975 | |
1976 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1977 | { | |
75a70cf9 | 1978 | gimple phi; |
1979 | gimple_vec phis; | |
88dbf20f | 1980 | |
70630fcd | 1981 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
1982 | continue; | |
48e1416a | 1983 | |
f1f41a6c | 1984 | phis = phis_to_rewrite[e->dest->index]; |
1985 | FOR_EACH_VEC_ELT (phis, i, phi) | |
88dbf20f | 1986 | { |
efbcb6de | 1987 | tree arg, lhs_sym, reaching_def = NULL; |
88dbf20f | 1988 | use_operand_p arg_p; |
1989 | ||
88536563 | 1990 | gcc_checking_assert (rewrite_uses_p (phi)); |
88dbf20f | 1991 | |
1992 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
1993 | arg = USE_FROM_PTR (arg_p); | |
1994 | ||
1995 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
1996 | continue; | |
1997 | ||
75a70cf9 | 1998 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
4fb5e5ca | 1999 | |
88dbf20f | 2000 | if (arg == NULL_TREE) |
2001 | { | |
2002 | /* When updating a PHI node for a recently introduced | |
2003 | symbol we may find NULL arguments. That's why we | |
2004 | take the symbol from the LHS of the PHI node. */ | |
efbcb6de | 2005 | reaching_def = get_reaching_def (lhs_sym); |
2006 | ||
88dbf20f | 2007 | } |
2008 | else | |
2009 | { | |
2010 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2011 | ||
e70e8b13 | 2012 | if (marked_for_renaming (sym)) |
efbcb6de | 2013 | reaching_def = get_reaching_def (sym); |
88dbf20f | 2014 | else if (is_old_name (arg)) |
efbcb6de | 2015 | reaching_def = get_reaching_def (arg); |
2016 | } | |
2017 | ||
2018 | /* Update the argument if there is a reaching def. */ | |
2019 | if (reaching_def) | |
2020 | { | |
2021 | gimple stmt; | |
2022 | source_location locus; | |
2023 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2024 | ||
2025 | SET_USE (arg_p, reaching_def); | |
2026 | stmt = SSA_NAME_DEF_STMT (reaching_def); | |
2027 | ||
48e1416a | 2028 | /* Single element PHI nodes behave like copies, so get the |
efbcb6de | 2029 | location from the phi argument. */ |
48e1416a | 2030 | if (gimple_code (stmt) == GIMPLE_PHI && |
efbcb6de | 2031 | gimple_phi_num_args (stmt) == 1) |
2032 | locus = gimple_phi_arg_location (stmt, 0); | |
2033 | else | |
2034 | locus = gimple_location (stmt); | |
2035 | ||
2036 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
88dbf20f | 2037 | } |
2038 | ||
efbcb6de | 2039 | |
88dbf20f | 2040 | if (e->flags & EDGE_ABNORMAL) |
2041 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2042 | } | |
2043 | } | |
2044 | } | |
2045 | ||
2046 | ||
6bf320fb | 2047 | /* Initialization of block data structures for the incremental SSA |
2048 | update pass. Create a block local stack of reaching definitions | |
2049 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2050 | new definitions for every PHI node in the block. */ | |
2051 | ||
2052 | static void | |
2053 | rewrite_update_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2054 | basic_block bb) | |
2055 | { | |
6bf320fb | 2056 | bool is_abnormal_phi; |
2057 | gimple_stmt_iterator gsi; | |
2058 | ||
2059 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
0ffbb1b6 | 2060 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
6bf320fb | 2061 | bb->index); |
2062 | ||
2063 | /* Mark the unwind point for this block. */ | |
f1f41a6c | 2064 | block_defs_stack.safe_push (NULL_TREE); |
6bf320fb | 2065 | |
2066 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
2067 | return; | |
2068 | ||
2069 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2070 | edge. */ | |
f1047120 | 2071 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
6bf320fb | 2072 | |
2073 | /* If any of the PHI nodes is a replacement for a name in | |
2074 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2075 | register it as a new definition for its corresponding name. Also | |
2076 | register definitions for names whose underlying symbols are | |
2077 | marked for renaming. */ | |
2078 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2079 | { | |
2080 | tree lhs, lhs_sym; | |
2081 | gimple phi = gsi_stmt (gsi); | |
2082 | ||
2083 | if (!register_defs_p (phi)) | |
2084 | continue; | |
48e1416a | 2085 | |
6bf320fb | 2086 | lhs = gimple_phi_result (phi); |
2087 | lhs_sym = SSA_NAME_VAR (lhs); | |
2088 | ||
e70e8b13 | 2089 | if (marked_for_renaming (lhs_sym)) |
6bf320fb | 2090 | register_new_update_single (lhs, lhs_sym); |
2091 | else | |
2092 | { | |
2093 | ||
2094 | /* If LHS is a new name, register a new definition for all | |
2095 | the names replaced by LHS. */ | |
2096 | if (is_new_name (lhs)) | |
2097 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
48e1416a | 2098 | |
6bf320fb | 2099 | /* If LHS is an OLD name, register it as a new definition |
2100 | for itself. */ | |
2101 | if (is_old_name (lhs)) | |
2102 | register_new_update_single (lhs, lhs); | |
2103 | } | |
2104 | ||
2105 | if (is_abnormal_phi) | |
2106 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2107 | } | |
2108 | ||
2109 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
08b7917c | 2110 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
cd610ee6 | 2111 | { |
88536563 | 2112 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
6bf320fb | 2113 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
cd610ee6 | 2114 | rewrite_update_stmt (gsi_stmt (gsi), gsi); |
2115 | } | |
6bf320fb | 2116 | |
2117 | /* Step 3. Update PHI nodes. */ | |
2118 | rewrite_update_phi_arguments (bb); | |
2119 | } | |
2120 | ||
2121 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2122 | the current reaching definition of every name re-written in BB to | |
2123 | the original reaching definition before visiting BB. This | |
2124 | unwinding must be done in the opposite order to what is done in | |
2125 | register_new_update_set. */ | |
2126 | ||
2127 | static void | |
2128 | rewrite_update_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2129 | basic_block bb ATTRIBUTE_UNUSED) | |
2130 | { | |
f1f41a6c | 2131 | while (block_defs_stack.length () > 0) |
6bf320fb | 2132 | { |
f1f41a6c | 2133 | tree var = block_defs_stack.pop (); |
6bf320fb | 2134 | tree saved_def; |
48e1416a | 2135 | |
6bf320fb | 2136 | /* NULL indicates the unwind stop point for this block (see |
2137 | rewrite_update_enter_block). */ | |
2138 | if (var == NULL) | |
2139 | return; | |
2140 | ||
f1f41a6c | 2141 | saved_def = block_defs_stack.pop (); |
74105c0d | 2142 | get_common_info (var)->current_def = saved_def; |
6bf320fb | 2143 | } |
2144 | } | |
2145 | ||
2146 | ||
88dbf20f | 2147 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
48e1416a | 2148 | form. |
88dbf20f | 2149 | |
2150 | ENTRY indicates the block where to start. Every block dominated by | |
2151 | ENTRY will be rewritten. | |
2152 | ||
2153 | WHAT indicates what actions will be taken by the renamer (see enum | |
2154 | rewrite_mode). | |
2155 | ||
2156 | BLOCKS are the set of interesting blocks for the dominator walker | |
2157 | to process. If this set is NULL, then all the nodes dominated | |
2158 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2159 | are not present in BLOCKS are ignored. */ | |
2160 | ||
2161 | static void | |
6bf320fb | 2162 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
88dbf20f | 2163 | { |
2164 | struct dom_walk_data walk_data; | |
48e1416a | 2165 | |
88dbf20f | 2166 | /* Rewrite all the basic blocks in the program. */ |
2167 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2168 | ||
2169 | /* Setup callbacks for the generic dominator tree walker. */ | |
2170 | memset (&walk_data, 0, sizeof (walk_data)); | |
2171 | ||
2172 | walk_data.dom_direction = CDI_DOMINATORS; | |
88dbf20f | 2173 | |
2174 | if (what == REWRITE_ALL) | |
6bf320fb | 2175 | { |
2176 | walk_data.before_dom_children = rewrite_enter_block; | |
2177 | walk_data.after_dom_children = rewrite_leave_block; | |
2178 | } | |
88dbf20f | 2179 | else if (what == REWRITE_UPDATE) |
6bf320fb | 2180 | { |
2181 | walk_data.before_dom_children = rewrite_update_enter_block; | |
2182 | walk_data.after_dom_children = rewrite_update_leave_block; | |
2183 | } | |
88dbf20f | 2184 | else |
2185 | gcc_unreachable (); | |
2186 | ||
f1f41a6c | 2187 | block_defs_stack.create (10); |
88dbf20f | 2188 | |
2189 | /* Initialize the dominator walker. */ | |
2190 | init_walk_dominator_tree (&walk_data); | |
2191 | ||
2192 | /* Recursively walk the dominator tree rewriting each statement in | |
2193 | each basic block. */ | |
2194 | walk_dominator_tree (&walk_data, entry); | |
2195 | ||
2196 | /* Finalize the dominator walker. */ | |
2197 | fini_walk_dominator_tree (&walk_data); | |
2198 | ||
2199 | /* Debugging dumps. */ | |
2200 | if (dump_file && (dump_flags & TDF_STATS)) | |
2201 | { | |
2202 | dump_dfa_stats (dump_file); | |
22d6c74e | 2203 | if (var_infos) |
88dbf20f | 2204 | dump_tree_ssa_stats (dump_file); |
2205 | } | |
48e1416a | 2206 | |
f1f41a6c | 2207 | block_defs_stack.release (); |
88dbf20f | 2208 | |
2209 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2210 | } | |
2211 | ||
2212 | ||
6bf320fb | 2213 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2214 | at the start of each block, and call mark_def_sites for each statement. */ | |
4ee9c684 | 2215 | |
f3d9a16c | 2216 | static void |
6bf320fb | 2217 | mark_def_sites_block (struct dom_walk_data *walk_data, basic_block bb) |
f3d9a16c | 2218 | { |
4fb5e5ca | 2219 | struct mark_def_sites_global_data *gd; |
6bf320fb | 2220 | bitmap kills; |
2221 | gimple_stmt_iterator gsi; | |
2222 | ||
4fb5e5ca | 2223 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; |
6bf320fb | 2224 | kills = gd->kills; |
2225 | ||
2226 | bitmap_clear (kills); | |
2227 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2228 | mark_def_sites (bb, gsi_stmt (gsi), kills); | |
e551bd1a | 2229 | } |
f3d9a16c | 2230 | |
f3d9a16c | 2231 | |
88dbf20f | 2232 | /* Mark the definition site blocks for each variable, so that we know |
2233 | where the variable is actually live. | |
2234 | ||
6bf320fb | 2235 | The INTERESTING_BLOCKS global will be filled in with all the blocks |
2236 | that should be processed by the renamer. It is assumed that the | |
2237 | caller has already initialized and zeroed it. */ | |
f3d9a16c | 2238 | |
88dbf20f | 2239 | static void |
6bf320fb | 2240 | mark_def_site_blocks (void) |
e551bd1a | 2241 | { |
e551bd1a | 2242 | struct dom_walk_data walk_data; |
2243 | struct mark_def_sites_global_data mark_def_sites_global_data; | |
f3d9a16c | 2244 | |
e551bd1a | 2245 | /* Setup callbacks for the generic dominator tree walker to find and |
2246 | mark definition sites. */ | |
e551bd1a | 2247 | walk_data.dom_direction = CDI_DOMINATORS; |
2248 | walk_data.initialize_block_local_data = NULL; | |
6bf320fb | 2249 | walk_data.before_dom_children = mark_def_sites_block; |
2250 | walk_data.after_dom_children = NULL; | |
f3d9a16c | 2251 | |
e551bd1a | 2252 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2253 | large enough to accommodate all the variables referenced in the | |
2254 | function, not just the ones we are renaming. */ | |
2255 | mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); | |
2256 | walk_data.global_data = &mark_def_sites_global_data; | |
4ee9c684 | 2257 | |
e551bd1a | 2258 | /* We do not have any local data. */ |
2259 | walk_data.block_local_data_size = 0; | |
2260 | ||
2261 | /* Initialize the dominator walker. */ | |
2262 | init_walk_dominator_tree (&walk_data); | |
2263 | ||
2264 | /* Recursively walk the dominator tree. */ | |
2265 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
2266 | ||
2267 | /* Finalize the dominator walker. */ | |
2268 | fini_walk_dominator_tree (&walk_data); | |
2269 | ||
2270 | /* We no longer need this bitmap, clear and free it. */ | |
2271 | BITMAP_FREE (mark_def_sites_global_data.kills); | |
4ee9c684 | 2272 | } |
2273 | ||
4ee9c684 | 2274 | |
4fb5e5ca | 2275 | /* Initialize internal data needed during renaming. */ |
2276 | ||
2277 | static void | |
2278 | init_ssa_renamer (void) | |
2279 | { | |
4fb5e5ca | 2280 | cfun->gimple_df->in_ssa_p = false; |
2281 | ||
2282 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
22d6c74e | 2283 | gcc_assert (var_infos == NULL); |
f1f41a6c | 2284 | var_infos = htab_create (vec_safe_length (cfun->local_decls), |
78d53e33 | 2285 | var_info_hash, var_info_eq, free); |
4fb5e5ca | 2286 | |
22d6c74e | 2287 | bitmap_obstack_initialize (&update_ssa_obstack); |
4fb5e5ca | 2288 | } |
2289 | ||
2290 | ||
2291 | /* Deallocate internal data structures used by the renamer. */ | |
2292 | ||
2293 | static void | |
2294 | fini_ssa_renamer (void) | |
2295 | { | |
22d6c74e | 2296 | if (var_infos) |
4fb5e5ca | 2297 | { |
22d6c74e | 2298 | htab_delete (var_infos); |
2299 | var_infos = NULL; | |
4fb5e5ca | 2300 | } |
2301 | ||
22d6c74e | 2302 | bitmap_obstack_release (&update_ssa_obstack); |
2303 | ||
e70e8b13 | 2304 | cfun->gimple_df->ssa_renaming_needed = 0; |
2305 | cfun->gimple_df->rename_vops = 0; | |
4fb5e5ca | 2306 | cfun->gimple_df->in_ssa_p = true; |
2307 | } | |
2308 | ||
e551bd1a | 2309 | /* Main entry point into the SSA builder. The renaming process |
88dbf20f | 2310 | proceeds in four main phases: |
4ee9c684 | 2311 | |
88dbf20f | 2312 | 1- Compute dominance frontier and immediate dominators, needed to |
2313 | insert PHI nodes and rename the function in dominator tree | |
2314 | order. | |
4ee9c684 | 2315 | |
88dbf20f | 2316 | 2- Find and mark all the blocks that define variables |
e551bd1a | 2317 | (mark_def_site_blocks). |
4ee9c684 | 2318 | |
88dbf20f | 2319 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
4ee9c684 | 2320 | |
88dbf20f | 2321 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
4ee9c684 | 2322 | |
21bdfe89 | 2323 | Steps 3 and 4 are done using the dominator tree walker |
88dbf20f | 2324 | (walk_dominator_tree). */ |
e551bd1a | 2325 | |
2a1990e9 | 2326 | static unsigned int |
88dbf20f | 2327 | rewrite_into_ssa (void) |
4ee9c684 | 2328 | { |
8a2980be | 2329 | bitmap_head *dfs; |
e551bd1a | 2330 | basic_block bb; |
ec11736b | 2331 | unsigned i; |
48e1416a | 2332 | |
88dbf20f | 2333 | /* Initialize operand data structures. */ |
5084b2e4 | 2334 | init_ssa_operands (cfun); |
4ee9c684 | 2335 | |
4fb5e5ca | 2336 | /* Initialize internal data needed by the renamer. */ |
2337 | init_ssa_renamer (); | |
2338 | ||
88dbf20f | 2339 | /* Initialize the set of interesting blocks. The callback |
2340 | mark_def_sites will add to this set those blocks that the renamer | |
2341 | should process. */ | |
2342 | interesting_blocks = sbitmap_alloc (last_basic_block); | |
53c5d9d4 | 2343 | bitmap_clear (interesting_blocks); |
4ee9c684 | 2344 | |
71797bf6 | 2345 | /* Initialize dominance frontier. */ |
8a2980be | 2346 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
e551bd1a | 2347 | FOR_EACH_BB (bb) |
8a2980be | 2348 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
4ee9c684 | 2349 | |
88dbf20f | 2350 | /* 1- Compute dominance frontiers. */ |
2351 | calculate_dominance_info (CDI_DOMINATORS); | |
e551bd1a | 2352 | compute_dominance_frontiers (dfs); |
4ee9c684 | 2353 | |
88dbf20f | 2354 | /* 2- Find and mark definition sites. */ |
6bf320fb | 2355 | mark_def_site_blocks (); |
88dbf20f | 2356 | |
2357 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
095dcfa3 | 2358 | insert_phi_nodes (dfs); |
4ee9c684 | 2359 | |
88dbf20f | 2360 | /* 4- Rename all the blocks. */ |
6bf320fb | 2361 | rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL); |
4ee9c684 | 2362 | |
e551bd1a | 2363 | /* Free allocated memory. */ |
2364 | FOR_EACH_BB (bb) | |
8a2980be | 2365 | bitmap_clear (&dfs[bb->index]); |
e551bd1a | 2366 | free (dfs); |
4ee9c684 | 2367 | |
acf11b62 | 2368 | sbitmap_free (interesting_blocks); |
2369 | ||
4fb5e5ca | 2370 | fini_ssa_renamer (); |
2371 | ||
ec11736b | 2372 | /* Try to get rid of all gimplifier generated temporaries by making |
2373 | its SSA names anonymous. This way we can garbage collect them | |
2374 | all after removing unused locals which we do in our TODO. */ | |
2375 | for (i = 1; i < num_ssa_names; ++i) | |
2376 | { | |
2377 | tree decl, name = ssa_name (i); | |
2378 | if (!name | |
2379 | || SSA_NAME_IS_DEFAULT_DEF (name)) | |
2380 | continue; | |
2381 | decl = SSA_NAME_VAR (name); | |
2382 | if (decl | |
2383 | && TREE_CODE (decl) == VAR_DECL | |
2384 | && !VAR_DECL_IS_VIRTUAL_OPERAND (decl) | |
2385 | && DECL_ARTIFICIAL (decl) | |
2386 | && DECL_IGNORED_P (decl) | |
2387 | && !DECL_NAME (decl)) | |
2388 | SET_SSA_NAME_VAR_OR_IDENTIFIER (name, NULL_TREE); | |
2389 | } | |
2390 | ||
2a1990e9 | 2391 | return 0; |
4ee9c684 | 2392 | } |
2393 | ||
2394 | ||
48e1416a | 2395 | struct gimple_opt_pass pass_build_ssa = |
4ee9c684 | 2396 | { |
20099e35 | 2397 | { |
2398 | GIMPLE_PASS, | |
e551bd1a | 2399 | "ssa", /* name */ |
c7875731 | 2400 | OPTGROUP_NONE, /* optinfo_flags */ |
e551bd1a | 2401 | NULL, /* gate */ |
88dbf20f | 2402 | rewrite_into_ssa, /* execute */ |
e551bd1a | 2403 | NULL, /* sub */ |
2404 | NULL, /* next */ | |
2405 | 0, /* static_pass_number */ | |
4b366dd3 | 2406 | TV_TREE_SSA_OTHER, /* tv_id */ |
b03e5397 | 2407 | PROP_cfg, /* properties_required */ |
e551bd1a | 2408 | PROP_ssa, /* properties_provided */ |
2409 | 0, /* properties_destroyed */ | |
2410 | 0, /* todo_flags_start */ | |
5aabc5f2 | 2411 | TODO_verify_ssa |
20099e35 | 2412 | | TODO_remove_unused_locals /* todo_flags_finish */ |
2413 | } | |
e551bd1a | 2414 | }; |
4ee9c684 | 2415 | |
2416 | ||
88dbf20f | 2417 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2418 | renamer. BLOCKS is the set of blocks that need updating. */ | |
4ee9c684 | 2419 | |
88dbf20f | 2420 | static void |
75a70cf9 | 2421 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
4ee9c684 | 2422 | { |
88536563 | 2423 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
75a70cf9 | 2424 | set_register_defs (stmt, true); |
88dbf20f | 2425 | |
2426 | if (insert_phi_p) | |
2427 | { | |
75a70cf9 | 2428 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
88dbf20f | 2429 | |
88dbf20f | 2430 | set_def_block (var, bb, is_phi_p); |
2431 | ||
2432 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2433 | site for both itself and all the old names replaced by it. */ | |
2434 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2435 | { | |
2436 | bitmap_iterator bi; | |
2437 | unsigned i; | |
2438 | bitmap set = names_replaced_by (var); | |
2439 | if (set) | |
2440 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2441 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2442 | } | |
2443 | } | |
2444 | } | |
2445 | ||
2446 | ||
2447 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2448 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
2920559d | 2449 | nodes. */ |
88dbf20f | 2450 | |
2451 | static inline void | |
75a70cf9 | 2452 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
88dbf20f | 2453 | { |
75a70cf9 | 2454 | basic_block def_bb = gimple_bb (stmt); |
70630fcd | 2455 | |
2920559d | 2456 | mark_block_for_update (def_bb); |
2457 | mark_block_for_update (bb); | |
2458 | ||
75a70cf9 | 2459 | if (gimple_code (stmt) == GIMPLE_PHI) |
70630fcd | 2460 | mark_phi_for_rewrite (def_bb, stmt); |
2461 | else | |
9845d120 | 2462 | { |
2463 | set_rewrite_uses (stmt, true); | |
2464 | ||
2465 | if (is_gimple_debug (stmt)) | |
2466 | return; | |
2467 | } | |
88dbf20f | 2468 | |
2469 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2470 | to BB. Note that we cannot just use the block holding VAR's | |
2471 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2472 | it will have several definitions (itself and all the names that | |
2473 | replace it). */ | |
2474 | if (insert_phi_p) | |
2475 | { | |
74105c0d | 2476 | struct def_blocks_d *db_p = get_def_blocks_for (get_common_info (var)); |
88dbf20f | 2477 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2478 | set_livein_block (var, bb); | |
2479 | } | |
2480 | } | |
2481 | ||
2482 | ||
88dbf20f | 2483 | /* Do a dominator walk starting at BB processing statements that |
e70e8b13 | 2484 | reference symbols in SSA operands. This is very similar to |
095dcfa3 | 2485 | mark_def_sites, but the scan handles statements whose operands may |
2920559d | 2486 | already be SSA names. |
88dbf20f | 2487 | |
095dcfa3 | 2488 | If INSERT_PHI_P is true, mark those uses as live in the |
2489 | corresponding block. This is later used by the PHI placement | |
4fb5e5ca | 2490 | algorithm to make PHI pruning decisions. |
2491 | ||
2492 | FIXME. Most of this would be unnecessary if we could associate a | |
2493 | symbol to all the SSA names that reference it. But that | |
2494 | sounds like it would be expensive to maintain. Still, it | |
2495 | would be interesting to see if it makes better sense to do | |
2496 | that. */ | |
88dbf20f | 2497 | |
2498 | static void | |
2920559d | 2499 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
88dbf20f | 2500 | { |
2501 | basic_block son; | |
75a70cf9 | 2502 | gimple_stmt_iterator si; |
f50cf978 | 2503 | edge e; |
2504 | edge_iterator ei; | |
88dbf20f | 2505 | |
2920559d | 2506 | mark_block_for_update (bb); |
2507 | ||
88dbf20f | 2508 | /* Process PHI nodes marking interesting those that define or use |
095dcfa3 | 2509 | the symbols that we are interested in. */ |
75a70cf9 | 2510 | for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) |
88dbf20f | 2511 | { |
75a70cf9 | 2512 | gimple phi = gsi_stmt (si); |
2513 | tree lhs_sym, lhs = gimple_phi_result (phi); | |
88dbf20f | 2514 | |
e70e8b13 | 2515 | if (TREE_CODE (lhs) == SSA_NAME |
0087edc6 | 2516 | && (! virtual_operand_p (lhs) |
2517 | || ! cfun->gimple_df->rename_vops)) | |
f50cf978 | 2518 | continue; |
75a70cf9 | 2519 | |
0087edc6 | 2520 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
e70e8b13 | 2521 | mark_for_renaming (lhs_sym); |
f50cf978 | 2522 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2523 | ||
2524 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2525 | to process the arguments of the phi nodes of the successor edges of | |
2526 | BB at the end of prepare_block_for_update, however, that turns out | |
2527 | to be significantly more expensive. Doing it here is conservatively | |
2528 | correct -- it may only cause us to believe a value to be live in a | |
2529 | block that also contains its definition, and thus insert a few more | |
2530 | phi nodes for it. */ | |
2531 | FOR_EACH_EDGE (e, ei, bb->preds) | |
75a70cf9 | 2532 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
88dbf20f | 2533 | } |
2534 | ||
2535 | /* Process the statements. */ | |
75a70cf9 | 2536 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
88dbf20f | 2537 | { |
75a70cf9 | 2538 | gimple stmt; |
88dbf20f | 2539 | ssa_op_iter i; |
2540 | use_operand_p use_p; | |
2541 | def_operand_p def_p; | |
48e1416a | 2542 | |
75a70cf9 | 2543 | stmt = gsi_stmt (si); |
88dbf20f | 2544 | |
e70e8b13 | 2545 | if (cfun->gimple_df->rename_vops |
2546 | && gimple_vuse (stmt)) | |
88dbf20f | 2547 | { |
e70e8b13 | 2548 | tree use = gimple_vuse (stmt); |
88dbf20f | 2549 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
e70e8b13 | 2550 | mark_for_renaming (sym); |
2551 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
88dbf20f | 2552 | } |
2553 | ||
e70e8b13 | 2554 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
88dbf20f | 2555 | { |
e70e8b13 | 2556 | tree use = USE_FROM_PTR (use_p); |
2557 | if (!DECL_P (use)) | |
2558 | continue; | |
2559 | mark_for_renaming (use); | |
2560 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2561 | } | |
2562 | ||
2563 | if (cfun->gimple_df->rename_vops | |
2564 | && gimple_vdef (stmt)) | |
2565 | { | |
2566 | tree def = gimple_vdef (stmt); | |
88dbf20f | 2567 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
e70e8b13 | 2568 | mark_for_renaming (sym); |
2569 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2570 | } | |
2571 | ||
2572 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2573 | { | |
2574 | tree def = DEF_FROM_PTR (def_p); | |
2575 | if (!DECL_P (def)) | |
2576 | continue; | |
2577 | mark_for_renaming (def); | |
2578 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
88dbf20f | 2579 | } |
2580 | } | |
2581 | ||
2582 | /* Now visit all the blocks dominated by BB. */ | |
095dcfa3 | 2583 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
4fb5e5ca | 2584 | son; |
2585 | son = next_dom_son (CDI_DOMINATORS, son)) | |
2920559d | 2586 | prepare_block_for_update (son, insert_phi_p); |
095dcfa3 | 2587 | } |
2588 | ||
2589 | ||
2590 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2591 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2592 | prepare_names_to_update. */ | |
2593 | ||
2594 | static void | |
2920559d | 2595 | prepare_use_sites_for (tree name, bool insert_phi_p) |
095dcfa3 | 2596 | { |
2597 | use_operand_p use_p; | |
2598 | imm_use_iterator iter; | |
2599 | ||
2600 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2601 | { | |
75a70cf9 | 2602 | gimple stmt = USE_STMT (use_p); |
2603 | basic_block bb = gimple_bb (stmt); | |
095dcfa3 | 2604 | |
75a70cf9 | 2605 | if (gimple_code (stmt) == GIMPLE_PHI) |
095dcfa3 | 2606 | { |
f50cf978 | 2607 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
75a70cf9 | 2608 | edge e = gimple_phi_arg_edge (stmt, ix); |
f50cf978 | 2609 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
095dcfa3 | 2610 | } |
2611 | else | |
2612 | { | |
2613 | /* For regular statements, mark this as an interesting use | |
2614 | for NAME. */ | |
2920559d | 2615 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
095dcfa3 | 2616 | } |
2617 | } | |
88dbf20f | 2618 | } |
2619 | ||
2620 | ||
095dcfa3 | 2621 | /* Helper for prepare_names_to_update. Mark the definition site for |
2622 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2623 | prepare_names_to_update. */ | |
88dbf20f | 2624 | |
2625 | static void | |
2920559d | 2626 | prepare_def_site_for (tree name, bool insert_phi_p) |
88dbf20f | 2627 | { |
75a70cf9 | 2628 | gimple stmt; |
88dbf20f | 2629 | basic_block bb; |
2630 | ||
88536563 | 2631 | gcc_checking_assert (names_to_release == NULL |
2632 | || !bitmap_bit_p (names_to_release, | |
2633 | SSA_NAME_VERSION (name))); | |
88dbf20f | 2634 | |
2635 | stmt = SSA_NAME_DEF_STMT (name); | |
75a70cf9 | 2636 | bb = gimple_bb (stmt); |
88dbf20f | 2637 | if (bb) |
2638 | { | |
88536563 | 2639 | gcc_checking_assert (bb->index < last_basic_block); |
2920559d | 2640 | mark_block_for_update (bb); |
2641 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
88dbf20f | 2642 | } |
2643 | } | |
2644 | ||
2645 | ||
095dcfa3 | 2646 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
2920559d | 2647 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2648 | PHI nodes for newly created names. */ | |
88dbf20f | 2649 | |
2650 | static void | |
2920559d | 2651 | prepare_names_to_update (bool insert_phi_p) |
88dbf20f | 2652 | { |
86c1585a | 2653 | unsigned i = 0; |
88dbf20f | 2654 | bitmap_iterator bi; |
3e790786 | 2655 | sbitmap_iterator sbi; |
88dbf20f | 2656 | |
2657 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2658 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2659 | defining basic block (which most likely doesn't exist). Notice | |
2660 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2661 | want to replace existing instances. */ | |
2662 | if (names_to_release) | |
2663 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
08b7917c | 2664 | bitmap_clear_bit (new_ssa_names, i); |
88dbf20f | 2665 | |
095dcfa3 | 2666 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2667 | names may be considered to be live-in on blocks that contain | |
2668 | definitions for their replacements. */ | |
0d211963 | 2669 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
2920559d | 2670 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
095dcfa3 | 2671 | |
88dbf20f | 2672 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2673 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
0d211963 | 2674 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
095dcfa3 | 2675 | { |
2676 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
2920559d | 2677 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2678 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
3e790786 | 2679 | } |
88dbf20f | 2680 | } |
2681 | ||
2682 | ||
2683 | /* Dump all the names replaced by NAME to FILE. */ | |
2684 | ||
2685 | void | |
2686 | dump_names_replaced_by (FILE *file, tree name) | |
2687 | { | |
2688 | unsigned i; | |
2689 | bitmap old_set; | |
2690 | bitmap_iterator bi; | |
2691 | ||
2692 | print_generic_expr (file, name, 0); | |
2693 | fprintf (file, " -> { "); | |
2694 | ||
2695 | old_set = names_replaced_by (name); | |
2696 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2697 | { | |
2698 | print_generic_expr (file, ssa_name (i), 0); | |
2699 | fprintf (file, " "); | |
2700 | } | |
2701 | ||
2702 | fprintf (file, "}\n"); | |
2703 | } | |
2704 | ||
2705 | ||
2706 | /* Dump all the names replaced by NAME to stderr. */ | |
2707 | ||
4b987fac | 2708 | DEBUG_FUNCTION void |
88dbf20f | 2709 | debug_names_replaced_by (tree name) |
2710 | { | |
2711 | dump_names_replaced_by (stderr, name); | |
2712 | } | |
2713 | ||
2714 | ||
095dcfa3 | 2715 | /* Dump SSA update information to FILE. */ |
88dbf20f | 2716 | |
2717 | void | |
095dcfa3 | 2718 | dump_update_ssa (FILE *file) |
88dbf20f | 2719 | { |
86c1585a | 2720 | unsigned i = 0; |
88dbf20f | 2721 | bitmap_iterator bi; |
2722 | ||
dd277d48 | 2723 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 2724 | return; |
2725 | ||
53c5d9d4 | 2726 | if (new_ssa_names && bitmap_first_set_bit (new_ssa_names) >= 0) |
88dbf20f | 2727 | { |
3e790786 | 2728 | sbitmap_iterator sbi; |
2729 | ||
88dbf20f | 2730 | fprintf (file, "\nSSA replacement table\n"); |
2731 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2732 | "O_1, ..., O_j\n\n"); | |
2733 | ||
0d211963 | 2734 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
3e790786 | 2735 | dump_names_replaced_by (file, ssa_name (i)); |
88dbf20f | 2736 | } |
2737 | ||
e70e8b13 | 2738 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
88dbf20f | 2739 | { |
0ffbb1b6 | 2740 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
e70e8b13 | 2741 | dump_decl_set (file, symbols_to_rename_set); |
dd277d48 | 2742 | fprintf (file, "\n"); |
88dbf20f | 2743 | } |
2744 | ||
88dbf20f | 2745 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2746 | { | |
0ffbb1b6 | 2747 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
88dbf20f | 2748 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2749 | { | |
2750 | print_generic_expr (file, ssa_name (i), 0); | |
2751 | fprintf (file, " "); | |
2752 | } | |
0ffbb1b6 | 2753 | fprintf (file, "\n"); |
88dbf20f | 2754 | } |
88dbf20f | 2755 | } |
2756 | ||
2757 | ||
095dcfa3 | 2758 | /* Dump SSA update information to stderr. */ |
88dbf20f | 2759 | |
4b987fac | 2760 | DEBUG_FUNCTION void |
095dcfa3 | 2761 | debug_update_ssa (void) |
88dbf20f | 2762 | { |
095dcfa3 | 2763 | dump_update_ssa (stderr); |
88dbf20f | 2764 | } |
2765 | ||
2766 | ||
2767 | /* Initialize data structures used for incremental SSA updates. */ | |
2768 | ||
2769 | static void | |
dd277d48 | 2770 | init_update_ssa (struct function *fn) |
88dbf20f | 2771 | { |
095dcfa3 | 2772 | /* Reserve more space than the current number of names. The calls to |
88dbf20f | 2773 | add_new_name_mapping are typically done after creating new SSA |
2774 | names, so we'll need to reallocate these arrays. */ | |
2775 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
53c5d9d4 | 2776 | bitmap_clear (old_ssa_names); |
88dbf20f | 2777 | |
2778 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
53c5d9d4 | 2779 | bitmap_clear (new_ssa_names); |
88dbf20f | 2780 | |
5eeafc2d | 2781 | bitmap_obstack_initialize (&update_ssa_obstack); |
2782 | ||
88dbf20f | 2783 | names_to_release = NULL; |
dd277d48 | 2784 | update_ssa_initialized_fn = fn; |
88dbf20f | 2785 | } |
2786 | ||
2787 | ||
2788 | /* Deallocate data structures used for incremental SSA updates. */ | |
2789 | ||
095dcfa3 | 2790 | void |
88dbf20f | 2791 | delete_update_ssa (void) |
2792 | { | |
2793 | unsigned i; | |
2794 | bitmap_iterator bi; | |
2795 | ||
2796 | sbitmap_free (old_ssa_names); | |
2797 | old_ssa_names = NULL; | |
2798 | ||
2799 | sbitmap_free (new_ssa_names); | |
2800 | new_ssa_names = NULL; | |
2801 | ||
e70e8b13 | 2802 | BITMAP_FREE (symbols_to_rename_set); |
2803 | symbols_to_rename_set = NULL; | |
f1f41a6c | 2804 | symbols_to_rename.release (); |
88dbf20f | 2805 | |
2806 | if (names_to_release) | |
2807 | { | |
2808 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2809 | release_ssa_name (ssa_name (i)); | |
2810 | BITMAP_FREE (names_to_release); | |
2811 | } | |
2812 | ||
2920559d | 2813 | clear_ssa_name_info (); |
4fb5e5ca | 2814 | |
2815 | fini_ssa_renamer (); | |
2816 | ||
2817 | if (blocks_with_phis_to_rewrite) | |
2818 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2819 | { | |
f1f41a6c | 2820 | gimple_vec phis = phis_to_rewrite[i]; |
2821 | phis.release (); | |
2822 | phis_to_rewrite[i].create (0); | |
4fb5e5ca | 2823 | } |
2824 | ||
2825 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2826 | BITMAP_FREE (blocks_to_update); | |
5eeafc2d | 2827 | |
dd277d48 | 2828 | update_ssa_initialized_fn = NULL; |
88dbf20f | 2829 | } |
2830 | ||
2831 | ||
2832 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
0dc262e0 | 2833 | operand pointed to by DEF_P with the newly created name. If DEF_P |
2834 | is NULL then STMT should be a GIMPLE assignment. | |
2835 | Return the new name and register the replacement mapping <NEW, OLD> in | |
88dbf20f | 2836 | update_ssa's tables. */ |
2837 | ||
2838 | tree | |
75a70cf9 | 2839 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
88dbf20f | 2840 | { |
0dc262e0 | 2841 | tree new_name; |
88dbf20f | 2842 | |
0dc262e0 | 2843 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
2844 | ||
2845 | if (!update_ssa_initialized_fn) | |
2846 | init_update_ssa (cfun); | |
2847 | ||
2848 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2849 | ||
2850 | new_name = duplicate_ssa_name (old_name, stmt); | |
2851 | if (def) | |
2852 | SET_DEF (def, new_name); | |
2853 | else | |
2854 | gimple_assign_set_lhs (stmt, new_name); | |
88dbf20f | 2855 | |
75a70cf9 | 2856 | if (gimple_code (stmt) == GIMPLE_PHI) |
88dbf20f | 2857 | { |
75a70cf9 | 2858 | basic_block bb = gimple_bb (stmt); |
88dbf20f | 2859 | |
2860 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
f1047120 | 2861 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
88dbf20f | 2862 | } |
2863 | ||
0dc262e0 | 2864 | add_new_name_mapping (new_name, old_name); |
88dbf20f | 2865 | |
2866 | /* For the benefit of passes that will be updating the SSA form on | |
2867 | their own, set the current reaching definition of OLD_NAME to be | |
2868 | NEW_NAME. */ | |
74105c0d | 2869 | get_ssa_name_ann (old_name)->info.current_def = new_name; |
88dbf20f | 2870 | |
0dc262e0 | 2871 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
88dbf20f | 2872 | |
0dc262e0 | 2873 | return new_name; |
88dbf20f | 2874 | } |
2875 | ||
2876 | ||
278611f2 | 2877 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
88dbf20f | 2878 | |
2879 | void | |
278611f2 | 2880 | mark_virtual_operands_for_renaming (struct function *fn) |
88dbf20f | 2881 | { |
278611f2 | 2882 | fn->gimple_df->ssa_renaming_needed = 1; |
2883 | fn->gimple_df->rename_vops = 1; | |
88dbf20f | 2884 | } |
2885 | ||
2886 | ||
dd277d48 | 2887 | /* Return true if there is any work to be done by update_ssa |
2888 | for function FN. */ | |
88dbf20f | 2889 | |
2890 | bool | |
dd277d48 | 2891 | need_ssa_update_p (struct function *fn) |
88dbf20f | 2892 | { |
dd277d48 | 2893 | gcc_assert (fn != NULL); |
2894 | return (update_ssa_initialized_fn == fn | |
e70e8b13 | 2895 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
88dbf20f | 2896 | } |
2897 | ||
88dbf20f | 2898 | /* Return true if name N has been registered in the replacement table. */ |
2899 | ||
2900 | bool | |
75a70cf9 | 2901 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
88dbf20f | 2902 | { |
dd277d48 | 2903 | if (!update_ssa_initialized_fn) |
88dbf20f | 2904 | return false; |
2905 | ||
dd277d48 | 2906 | gcc_assert (update_ssa_initialized_fn == cfun); |
2907 | ||
2908 | return is_new_name (n) || is_old_name (n); | |
88dbf20f | 2909 | } |
2910 | ||
2911 | ||
88dbf20f | 2912 | /* Mark NAME to be released after update_ssa has finished. */ |
2913 | ||
2914 | void | |
2915 | release_ssa_name_after_update_ssa (tree name) | |
2916 | { | |
dd277d48 | 2917 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
88dbf20f | 2918 | |
2919 | if (names_to_release == NULL) | |
2920 | names_to_release = BITMAP_ALLOC (NULL); | |
2921 | ||
2922 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2923 | } | |
2924 | ||
2925 | ||
2926 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2927 | frontier information. BLOCKS is the set of blocks to be updated. | |
2928 | ||
2929 | This is slightly different than the regular PHI insertion | |
2930 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2931 | real names (i.e., GIMPLE registers) are inserted: | |
48e1416a | 2932 | |
88dbf20f | 2933 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
2934 | nodes inside the region affected by the block that defines VAR | |
2935 | and the blocks that define all its replacements. All these | |
095dcfa3 | 2936 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
88dbf20f | 2937 | |
2938 | First, we compute the entry point to the region (ENTRY). This is | |
2939 | given by the nearest common dominator to all the definition | |
2940 | blocks. When computing the iterated dominance frontier (IDF), any | |
2941 | block not strictly dominated by ENTRY is ignored. | |
2942 | ||
2943 | We then call the standard PHI insertion algorithm with the pruned | |
2944 | IDF. | |
2945 | ||
2946 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
2947 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
2948 | ||
2949 | static void | |
8a2980be | 2950 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
88dbf20f | 2951 | unsigned update_flags) |
2952 | { | |
2953 | basic_block entry; | |
2954 | struct def_blocks_d *db; | |
2955 | bitmap idf, pruned_idf; | |
2956 | bitmap_iterator bi; | |
2957 | unsigned i; | |
2958 | ||
88dbf20f | 2959 | if (TREE_CODE (var) == SSA_NAME) |
1b4345f7 | 2960 | gcc_checking_assert (is_old_name (var)); |
88dbf20f | 2961 | else |
e70e8b13 | 2962 | gcc_checking_assert (marked_for_renaming (var)); |
88dbf20f | 2963 | |
2964 | /* Get all the definition sites for VAR. */ | |
2965 | db = find_def_blocks_for (var); | |
2966 | ||
2967 | /* No need to do anything if there were no definitions to VAR. */ | |
2968 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
2969 | return; | |
2970 | ||
2971 | /* Compute the initial iterated dominance frontier. */ | |
4fb5e5ca | 2972 | idf = compute_idf (db->def_blocks, dfs); |
88dbf20f | 2973 | pruned_idf = BITMAP_ALLOC (NULL); |
2974 | ||
2975 | if (TREE_CODE (var) == SSA_NAME) | |
2976 | { | |
2977 | if (update_flags == TODO_update_ssa) | |
2978 | { | |
2979 | /* If doing regular SSA updates for GIMPLE registers, we are | |
2980 | only interested in IDF blocks dominated by the nearest | |
2981 | common dominator of all the definition blocks. */ | |
2982 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
2983 | db->def_blocks); | |
88dbf20f | 2984 | if (entry != ENTRY_BLOCK_PTR) |
2985 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) | |
2986 | if (BASIC_BLOCK (i) != entry | |
2987 | && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) | |
2988 | bitmap_set_bit (pruned_idf, i); | |
2989 | } | |
2990 | else | |
2991 | { | |
2992 | /* Otherwise, do not prune the IDF for VAR. */ | |
88536563 | 2993 | gcc_checking_assert (update_flags == TODO_update_ssa_full_phi); |
88dbf20f | 2994 | bitmap_copy (pruned_idf, idf); |
2995 | } | |
2996 | } | |
2997 | else | |
2998 | { | |
2999 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3000 | for the first time, so we need to compute the full IDF for | |
3001 | it. */ | |
3002 | bitmap_copy (pruned_idf, idf); | |
88dbf20f | 3003 | } |
3004 | ||
3005 | if (!bitmap_empty_p (pruned_idf)) | |
3006 | { | |
3007 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3008 | are included in the region to be updated. The feeding blocks | |
3009 | are important to guarantee that the PHI arguments are renamed | |
3010 | properly. */ | |
4fb5e5ca | 3011 | |
3012 | /* FIXME, this is not needed if we are updating symbols. We are | |
3013 | already starting at the ENTRY block anyway. */ | |
88dbf20f | 3014 | bitmap_ior_into (blocks, pruned_idf); |
3015 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3016 | { | |
3017 | edge e; | |
3018 | edge_iterator ei; | |
3019 | basic_block bb = BASIC_BLOCK (i); | |
3020 | ||
3021 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3022 | if (e->src->index >= 0) | |
3023 | bitmap_set_bit (blocks, e->src->index); | |
3024 | } | |
3025 | ||
3026 | insert_phi_nodes_for (var, pruned_idf, true); | |
3027 | } | |
3028 | ||
3029 | BITMAP_FREE (pruned_idf); | |
3030 | BITMAP_FREE (idf); | |
3031 | } | |
3032 | ||
3033 | ||
3034 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3035 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3036 | ||
3037 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3038 | NEW_SSA_NAMES are all re-written to be reached by the | |
3039 | appropriate definition from NEW_SSA_NAMES. | |
3040 | ||
3041 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3042 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3043 | ||
3044 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
0dc262e0 | 3045 | calling create_new_def_for to create new defs for names that the |
88dbf20f | 3046 | caller wants to replace. |
3047 | ||
0dc262e0 | 3048 | The caller cretaes the new names to be inserted and the names that need |
3049 | to be replaced by calling create_new_def_for for each old definition | |
3050 | to be replaced. Note that the function assumes that the | |
3051 | new defining statement has already been inserted in the IL. | |
88dbf20f | 3052 | |
3053 | For instance, given the following code: | |
3054 | ||
3055 | 1 L0: | |
3056 | 2 x_1 = PHI (0, x_5) | |
3057 | 3 if (x_1 < 10) | |
3058 | 4 if (x_1 > 7) | |
3059 | 5 y_2 = 0 | |
3060 | 6 else | |
3061 | 7 y_3 = x_1 + x_7 | |
3062 | 8 endif | |
3063 | 9 x_5 = x_1 + 1 | |
3064 | 10 goto L0; | |
3065 | 11 endif | |
3066 | ||
3067 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3068 | ||
3069 | 1 L0: | |
3070 | 2 x_1 = PHI (0, x_5) | |
3071 | 3 if (x_1 < 10) | |
3072 | 4 x_10 = ... | |
3073 | 5 if (x_1 > 7) | |
3074 | 6 y_2 = 0 | |
3075 | 7 else | |
3076 | 8 x_11 = ... | |
3077 | 9 y_3 = x_1 + x_7 | |
3078 | 10 endif | |
3079 | 11 x_5 = x_1 + 1 | |
3080 | 12 goto L0; | |
3081 | 13 endif | |
3082 | ||
3083 | We want to replace all the uses of x_1 with the new definitions of | |
3084 | x_10 and x_11. Note that the only uses that should be replaced are | |
3085 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3086 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3087 | renaming). | |
3088 | ||
3089 | Additionally, we may need to insert a PHI node at line 11 because | |
3090 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3091 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3092 | nodes is optional. They are not strictly necessary to preserve the | |
3093 | SSA form, and depending on what the caller inserted, they may not | |
3094 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3095 | aspects of how update_ssa operates, see the documentation for | |
3096 | TODO_update_ssa*. */ | |
3097 | ||
3098 | void | |
3099 | update_ssa (unsigned update_flags) | |
3100 | { | |
88dbf20f | 3101 | basic_block bb, start_bb; |
3102 | bitmap_iterator bi; | |
86c1585a | 3103 | unsigned i = 0; |
88dbf20f | 3104 | bool insert_phi_p; |
3e790786 | 3105 | sbitmap_iterator sbi; |
e70e8b13 | 3106 | tree sym; |
88dbf20f | 3107 | |
2670407e | 3108 | /* Only one update flag should be set. */ |
3109 | gcc_assert (update_flags == TODO_update_ssa | |
3110 | || update_flags == TODO_update_ssa_no_phi | |
3111 | || update_flags == TODO_update_ssa_full_phi | |
3112 | || update_flags == TODO_update_ssa_only_virtuals); | |
3113 | ||
dd277d48 | 3114 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 3115 | return; |
3116 | ||
3117 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
3118 | ||
0ffbb1b6 | 3119 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3120 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3121 | ||
dd277d48 | 3122 | if (!update_ssa_initialized_fn) |
3123 | init_update_ssa (cfun); | |
2670407e | 3124 | else if (update_flags == TODO_update_ssa_only_virtuals) |
3125 | { | |
3126 | /* If we only need to update virtuals, remove all the mappings for | |
3127 | real names before proceeding. The caller is responsible for | |
3128 | having dealt with the name mappings before calling update_ssa. */ | |
53c5d9d4 | 3129 | bitmap_clear (old_ssa_names); |
3130 | bitmap_clear (new_ssa_names); | |
2670407e | 3131 | } |
3132 | ||
dd277d48 | 3133 | gcc_assert (update_ssa_initialized_fn == cfun); |
3134 | ||
70630fcd | 3135 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
f1f41a6c | 3136 | if (!phis_to_rewrite.exists ()) |
3137 | phis_to_rewrite.create (last_basic_block + 1); | |
2920559d | 3138 | blocks_to_update = BITMAP_ALLOC (NULL); |
70630fcd | 3139 | |
88dbf20f | 3140 | /* Ensure that the dominance information is up-to-date. */ |
3141 | calculate_dominance_info (CDI_DOMINATORS); | |
3142 | ||
095dcfa3 | 3143 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
88dbf20f | 3144 | |
095dcfa3 | 3145 | /* If there are names defined in the replacement table, prepare |
3146 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3147 | OLD_SSA_NAMES. */ | |
53c5d9d4 | 3148 | if (bitmap_first_set_bit (new_ssa_names) >= 0) |
095dcfa3 | 3149 | { |
2920559d | 3150 | prepare_names_to_update (insert_phi_p); |
095dcfa3 | 3151 | |
3152 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3153 | removal, and there are no symbols to rename, then there's | |
3154 | nothing else to do. */ | |
53c5d9d4 | 3155 | if (bitmap_first_set_bit (new_ssa_names) < 0 |
e70e8b13 | 3156 | && !cfun->gimple_df->ssa_renaming_needed) |
095dcfa3 | 3157 | goto done; |
3158 | } | |
3159 | ||
3160 | /* Next, determine the block at which to start the renaming process. */ | |
e70e8b13 | 3161 | if (cfun->gimple_df->ssa_renaming_needed) |
095dcfa3 | 3162 | { |
22d6c74e | 3163 | /* If we rename bare symbols initialize the mapping to |
3164 | auxiliar info we need to keep track of. */ | |
78d53e33 | 3165 | var_infos = htab_create (47, var_info_hash, var_info_eq, free); |
22d6c74e | 3166 | |
095dcfa3 | 3167 | /* If we have to rename some symbols from scratch, we need to |
3168 | start the process at the root of the CFG. FIXME, it should | |
3169 | be possible to determine the nearest block that had a | |
3170 | definition for each of the symbols that are marked for | |
3171 | updating. For now this seems more work than it's worth. */ | |
3172 | start_bb = ENTRY_BLOCK_PTR; | |
3173 | ||
4fb5e5ca | 3174 | /* Traverse the CFG looking for existing definitions and uses of |
e70e8b13 | 3175 | symbols in SSA operands. Mark interesting blocks and |
4fb5e5ca | 3176 | statements and set local live-in information for the PHI |
3177 | placement heuristics. */ | |
2920559d | 3178 | prepare_block_for_update (start_bb, insert_phi_p); |
f8aa507d | 3179 | |
3180 | #ifdef ENABLE_CHECKING | |
3181 | for (i = 1; i < num_ssa_names; ++i) | |
3182 | { | |
3183 | tree name = ssa_name (i); | |
3184 | if (!name | |
3185 | || virtual_operand_p (name)) | |
3186 | continue; | |
3187 | ||
3188 | /* For all but virtual operands, which do not have SSA names | |
3189 | with overlapping life ranges, ensure that symbols marked | |
3190 | for renaming do not have existing SSA names associated with | |
3191 | them as we do not re-write them out-of-SSA before going | |
3192 | into SSA for the remaining symbol uses. */ | |
3193 | if (marked_for_renaming (SSA_NAME_VAR (name))) | |
3194 | { | |
3195 | fprintf (stderr, "Existing SSA name for symbol marked for " | |
3196 | "renaming: "); | |
3197 | print_generic_expr (stderr, name, TDF_SLIM); | |
3198 | fprintf (stderr, "\n"); | |
3199 | internal_error ("SSA corruption"); | |
3200 | } | |
3201 | } | |
3202 | #endif | |
88dbf20f | 3203 | } |
3204 | else | |
095dcfa3 | 3205 | { |
3206 | /* Otherwise, the entry block to the region is the nearest | |
3207 | common dominator for the blocks in BLOCKS. */ | |
2920559d | 3208 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3209 | blocks_to_update); | |
095dcfa3 | 3210 | } |
88dbf20f | 3211 | |
3212 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
095dcfa3 | 3213 | of every block, creating new definitions for names in OLD_SSA_NAMES |
e70e8b13 | 3214 | and for symbols found. */ |
88dbf20f | 3215 | if (insert_phi_p) |
3216 | { | |
8a2980be | 3217 | bitmap_head *dfs; |
66d00abf | 3218 | |
3219 | /* If the caller requested PHI nodes to be added, compute | |
3220 | dominance frontiers. */ | |
8a2980be | 3221 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
66d00abf | 3222 | FOR_EACH_BB (bb) |
8a2980be | 3223 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
66d00abf | 3224 | compute_dominance_frontiers (dfs); |
3225 | ||
53c5d9d4 | 3226 | if (bitmap_first_set_bit (old_ssa_names) >= 0) |
88dbf20f | 3227 | { |
3e790786 | 3228 | sbitmap_iterator sbi; |
3229 | ||
095dcfa3 | 3230 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3231 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3232 | will grow while we are traversing it (but it will not | |
3233 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3234 | for traversal. */ | |
156093aa | 3235 | sbitmap tmp = sbitmap_alloc (SBITMAP_SIZE (old_ssa_names)); |
53c5d9d4 | 3236 | bitmap_copy (tmp, old_ssa_names); |
0d211963 | 3237 | EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi) |
2920559d | 3238 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
3e790786 | 3239 | update_flags); |
88dbf20f | 3240 | sbitmap_free (tmp); |
3241 | } | |
3242 | ||
f1f41a6c | 3243 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
e70e8b13 | 3244 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, |
4fb5e5ca | 3245 | update_flags); |
88dbf20f | 3246 | |
66d00abf | 3247 | FOR_EACH_BB (bb) |
8a2980be | 3248 | bitmap_clear (&dfs[bb->index]); |
66d00abf | 3249 | free (dfs); |
3250 | ||
88dbf20f | 3251 | /* Insertion of PHI nodes may have added blocks to the region. |
3252 | We need to re-compute START_BB to include the newly added | |
3253 | blocks. */ | |
3254 | if (start_bb != ENTRY_BLOCK_PTR) | |
2920559d | 3255 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3256 | blocks_to_update); | |
88dbf20f | 3257 | } |
3258 | ||
3259 | /* Reset the current definition for name and symbol before renaming | |
3260 | the sub-graph. */ | |
0d211963 | 3261 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
74105c0d | 3262 | get_ssa_name_ann (ssa_name (i))->info.current_def = NULL_TREE; |
88dbf20f | 3263 | |
f1f41a6c | 3264 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
74105c0d | 3265 | get_var_info (sym)->info.current_def = NULL_TREE; |
88dbf20f | 3266 | |
3267 | /* Now start the renaming process at START_BB. */ | |
6bf320fb | 3268 | interesting_blocks = sbitmap_alloc (last_basic_block); |
53c5d9d4 | 3269 | bitmap_clear (interesting_blocks); |
2920559d | 3270 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
08b7917c | 3271 | bitmap_set_bit (interesting_blocks, i); |
88dbf20f | 3272 | |
6bf320fb | 3273 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
88dbf20f | 3274 | |
6bf320fb | 3275 | sbitmap_free (interesting_blocks); |
88dbf20f | 3276 | |
3277 | /* Debugging dumps. */ | |
3278 | if (dump_file) | |
3279 | { | |
3280 | int c; | |
3281 | unsigned i; | |
3282 | ||
095dcfa3 | 3283 | dump_update_ssa (dump_file); |
88dbf20f | 3284 | |
0ffbb1b6 | 3285 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
88dbf20f | 3286 | start_bb->index); |
3287 | ||
3288 | c = 0; | |
2920559d | 3289 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
88dbf20f | 3290 | c++; |
3291 | fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block); | |
0ffbb1b6 | 3292 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
88dbf20f | 3293 | c, PERCENT (c, last_basic_block)); |
3294 | ||
3295 | if (dump_flags & TDF_DETAILS) | |
3296 | { | |
7ef97146 | 3297 | fprintf (dump_file, "Affected blocks:"); |
2920559d | 3298 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
7ef97146 | 3299 | fprintf (dump_file, " %u", i); |
88dbf20f | 3300 | fprintf (dump_file, "\n"); |
3301 | } | |
3302 | ||
3303 | fprintf (dump_file, "\n\n"); | |
3304 | } | |
3305 | ||
3306 | /* Free allocated memory. */ | |
095dcfa3 | 3307 | done: |
88dbf20f | 3308 | delete_update_ssa (); |
3309 | ||
3310 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3311 | } |