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Commit | Line | Data |
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6de9cd9a | 1 | /* Rewrite a program in Normal form into SSA. |
ddb555ed | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011 |
9dcd6f09 | 3 | Free Software Foundation, Inc. |
6de9cd9a DN |
4 | Contributed by Diego Novillo <dnovillo@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
9dcd6f09 | 10 | the Free Software Foundation; either version 3, or (at your option) |
6de9cd9a DN |
11 | any later version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
27 | #include "flags.h" | |
6de9cd9a DN |
28 | #include "tm_p.h" |
29 | #include "langhooks.h" | |
6de9cd9a | 30 | #include "basic-block.h" |
6de9cd9a | 31 | #include "function.h" |
cf835838 | 32 | #include "gimple-pretty-print.h" |
6de9cd9a DN |
33 | #include "bitmap.h" |
34 | #include "tree-flow.h" | |
726a989a | 35 | #include "gimple.h" |
6de9cd9a | 36 | #include "tree-inline.h" |
6de9cd9a | 37 | #include "hashtab.h" |
6de9cd9a DN |
38 | #include "tree-pass.h" |
39 | #include "cfgloop.h" | |
40 | #include "domwalk.h" | |
84d65814 | 41 | #include "params.h" |
e3df376d | 42 | #include "vecprim.h" |
6de9cd9a | 43 | |
726a989a | 44 | |
6de9cd9a DN |
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 | ||
6de9cd9a DN |
51 | /* Structure to map a variable VAR to the set of blocks that contain |
52 | definitions for VAR. */ | |
53 | struct def_blocks_d | |
54 | { | |
6de9cd9a DN |
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 | ||
7256233c | 59 | /* Blocks that contain a PHI node for VAR. */ |
5f240ec4 ZD |
60 | bitmap phi_blocks; |
61 | ||
6de9cd9a DN |
62 | /* Blocks where VAR is live-on-entry. Similar semantics as |
63 | DEF_BLOCKS. */ | |
64 | bitmap livein_blocks; | |
65 | }; | |
66 | ||
d9ed2fbd RG |
67 | typedef struct def_blocks_d *def_blocks_p; |
68 | ||
6de9cd9a | 69 | |
9fae925b | 70 | /* Stack of trees used to restore the global currdefs to its original |
0bca51f0 DN |
71 | state after completing rewriting of a block and its dominator |
72 | children. Its elements have the following properties: | |
9fae925b | 73 | |
38635499 DN |
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. | |
9fae925b | 80 | |
0bca51f0 DN |
81 | - A _DECL node indicates that the underlying variable has no |
82 | current definition. | |
7256233c | 83 | |
38635499 | 84 | - A NULL node at the top entry is used to mark the last slot |
0bca51f0 | 85 | associated with the current block. */ |
d4e6fecb | 86 | static VEC(tree,heap) *block_defs_stack; |
3a2e4b46 | 87 | |
726a989a | 88 | |
0bca51f0 DN |
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 | ||
ccf5c864 | 97 | sbitmap interesting_blocks; |
726a989a | 98 | |
0bca51f0 DN |
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 | ||
726a989a | 104 | static VEC(gimple_vec, heap) *phis_to_rewrite; |
2ce79879 ZD |
105 | |
106 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
2ce79879 ZD |
107 | static bitmap blocks_with_phis_to_rewrite; |
108 | ||
0bca51f0 DN |
109 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
110 | to grow as the callers to register_new_name_mapping will typically | |
111 | create new names on the fly. FIXME. Currently set to 1/3 to avoid | |
112 | frequent reallocations but still need to find a reasonable growth | |
113 | strategy. */ | |
114 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) | |
115 | ||
0bca51f0 | 116 | |
5006671f RG |
117 | /* The function the SSA updating data structures have been initialized for. |
118 | NULL if they need to be initialized by register_new_name_mapping. */ | |
119 | static struct function *update_ssa_initialized_fn = NULL; | |
0bca51f0 | 120 | |
6de9cd9a DN |
121 | /* Global data to attach to the main dominator walk structure. */ |
122 | struct mark_def_sites_global_data | |
123 | { | |
0bca51f0 DN |
124 | /* This bitmap contains the variables which are set before they |
125 | are used in a basic block. */ | |
7d793e36 | 126 | bitmap kills; |
6de9cd9a DN |
127 | }; |
128 | ||
5f240ec4 | 129 | |
b4e209fd RG |
130 | /* Information stored for decls. */ |
131 | struct var_info_d | |
132 | { | |
133 | /* The variable. */ | |
134 | tree var; | |
135 | ||
136 | /* This field indicates whether or not the variable may need PHI nodes. | |
137 | See the enum's definition for more detailed information about the | |
138 | states. */ | |
139 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
140 | ||
141 | /* The current reaching definition replacing this SSA name. */ | |
142 | tree current_def; | |
143 | ||
144 | /* Definitions for this VAR. */ | |
145 | struct def_blocks_d def_blocks; | |
146 | }; | |
147 | ||
148 | /* The information associated with decls. */ | |
149 | typedef struct var_info_d *var_info_p; | |
150 | ||
151 | DEF_VEC_P(var_info_p); | |
152 | DEF_VEC_ALLOC_P(var_info_p,heap); | |
153 | ||
154 | /* Each entry in VAR_INFOS contains an element of type STRUCT | |
155 | VAR_INFO_D. */ | |
156 | static htab_t var_infos; | |
157 | ||
158 | ||
0bca51f0 | 159 | /* Information stored for SSA names. */ |
5f240ec4 ZD |
160 | struct ssa_name_info |
161 | { | |
891f2df6 RG |
162 | /* Age of this record (so that info_for_ssa_name table can be cleared |
163 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
164 | are assumed to be null. */ | |
165 | unsigned age; | |
95dd3097 | 166 | |
5f240ec4 ZD |
167 | /* This field indicates whether or not the variable may need PHI nodes. |
168 | See the enum's definition for more detailed information about the | |
169 | states. */ | |
170 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
171 | ||
891f2df6 RG |
172 | /* The current reaching definition replacing this SSA name. */ |
173 | tree current_def; | |
174 | ||
175 | /* Replacement mappings, allocated from update_ssa_obstack. */ | |
176 | bitmap repl_set; | |
b4e209fd RG |
177 | |
178 | /* Definitions for this SSA name. */ | |
179 | struct def_blocks_d def_blocks; | |
5f240ec4 | 180 | }; |
6de9cd9a | 181 | |
95dd3097 ZD |
182 | /* The information associated with names. */ |
183 | typedef struct ssa_name_info *ssa_name_info_p; | |
184 | DEF_VEC_P (ssa_name_info_p); | |
185 | DEF_VEC_ALLOC_P (ssa_name_info_p, heap); | |
186 | ||
187 | static VEC(ssa_name_info_p, heap) *info_for_ssa_name; | |
188 | static unsigned current_info_for_ssa_name_age; | |
189 | ||
891f2df6 RG |
190 | static bitmap_obstack update_ssa_obstack; |
191 | ||
95dd3097 | 192 | /* The set of blocks affected by update_ssa. */ |
95dd3097 | 193 | static bitmap blocks_to_update; |
6de9cd9a | 194 | |
0bca51f0 DN |
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 | ||
0bca51f0 | 211 | |
7d5f9cc6 | 212 | |
84d65814 DN |
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); | |
38635499 DN |
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); | |
b4e209fd RG |
223 | extern void dump_var_infos (FILE *); |
224 | extern void debug_var_infos (void); | |
38635499 DN |
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); | |
84d65814 | 229 | |
13714310 RG |
230 | |
231 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ | |
232 | static bitmap symbols_to_rename_set; | |
233 | static VEC(tree,heap) *symbols_to_rename; | |
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))) | |
243 | VEC_safe_push (tree, heap, symbols_to_rename, sym); | |
244 | } | |
245 | ||
246 | /* Return true if SYM is marked for renaming. */ | |
247 | ||
248 | static bool | |
249 | marked_for_renaming (tree sym) | |
250 | { | |
251 | if (!symbols_to_rename_set) | |
252 | return false; | |
253 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
254 | } | |
255 | ||
256 | ||
726a989a RB |
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 | ||
5f240ec4 ZD |
301 | /* Get the information associated with NAME. */ |
302 | ||
38635499 | 303 | static inline ssa_name_info_p |
5f240ec4 ZD |
304 | get_ssa_name_ann (tree name) |
305 | { | |
95dd3097 ZD |
306 | unsigned ver = SSA_NAME_VERSION (name); |
307 | unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name); | |
308 | struct ssa_name_info *info; | |
309 | ||
310 | if (ver >= len) | |
311 | { | |
312 | unsigned new_len = num_ssa_names; | |
313 | ||
314 | VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name, new_len); | |
315 | while (len++ < new_len) | |
316 | { | |
317 | struct ssa_name_info *info = XCNEW (struct ssa_name_info); | |
318 | info->age = current_info_for_ssa_name_age; | |
319 | VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info); | |
320 | } | |
321 | } | |
322 | ||
323 | info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver); | |
324 | if (info->age < current_info_for_ssa_name_age) | |
325 | { | |
32e8bb8e | 326 | info->need_phi_state = NEED_PHI_STATE_UNKNOWN; |
95dd3097 | 327 | info->current_def = NULL_TREE; |
891f2df6 | 328 | info->repl_set = NULL; |
b4e209fd RG |
329 | info->def_blocks.def_blocks = NULL; |
330 | info->def_blocks.phi_blocks = NULL; | |
331 | info->def_blocks.livein_blocks = NULL; | |
95dd3097 ZD |
332 | info->age = current_info_for_ssa_name_age; |
333 | } | |
5f240ec4 | 334 | |
95dd3097 | 335 | return info; |
5f240ec4 ZD |
336 | } |
337 | ||
b4e209fd RG |
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 | ||
38635499 DN |
357 | |
358 | /* Clears info for SSA names. */ | |
95dd3097 ZD |
359 | |
360 | static void | |
361 | clear_ssa_name_info (void) | |
362 | { | |
363 | current_info_for_ssa_name_age++; | |
891f2df6 RG |
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); | |
95dd3097 | 368 | } |
7256233c | 369 | |
38635499 DN |
370 | |
371 | /* Get phi_state field for VAR. */ | |
5f240ec4 ZD |
372 | |
373 | static inline enum need_phi_state | |
374 | get_phi_state (tree var) | |
375 | { | |
376 | if (TREE_CODE (var) == SSA_NAME) | |
377 | return get_ssa_name_ann (var)->need_phi_state; | |
378 | else | |
b4e209fd | 379 | return get_var_info (var)->need_phi_state; |
5f240ec4 ZD |
380 | } |
381 | ||
7256233c | 382 | |
5f240ec4 ZD |
383 | /* Sets phi_state field for VAR to STATE. */ |
384 | ||
385 | static inline void | |
386 | set_phi_state (tree var, enum need_phi_state state) | |
387 | { | |
388 | if (TREE_CODE (var) == SSA_NAME) | |
389 | get_ssa_name_ann (var)->need_phi_state = state; | |
390 | else | |
b4e209fd | 391 | get_var_info (var)->need_phi_state = state; |
5f240ec4 ZD |
392 | } |
393 | ||
7256233c | 394 | |
5f240ec4 ZD |
395 | /* Return the current definition for VAR. */ |
396 | ||
84d65814 | 397 | tree |
5f240ec4 ZD |
398 | get_current_def (tree var) |
399 | { | |
400 | if (TREE_CODE (var) == SSA_NAME) | |
401 | return get_ssa_name_ann (var)->current_def; | |
402 | else | |
b4e209fd | 403 | return get_var_info (var)->current_def; |
5f240ec4 ZD |
404 | } |
405 | ||
7256233c | 406 | |
5f240ec4 ZD |
407 | /* Sets current definition of VAR to DEF. */ |
408 | ||
84d65814 | 409 | void |
5f240ec4 ZD |
410 | set_current_def (tree var, tree def) |
411 | { | |
412 | if (TREE_CODE (var) == SSA_NAME) | |
413 | get_ssa_name_ann (var)->current_def = def; | |
414 | else | |
b4e209fd | 415 | get_var_info (var)->current_def = def; |
5f240ec4 ZD |
416 | } |
417 | ||
7256233c | 418 | |
fa10beec | 419 | /* Compute global livein information given the set of blocks where |
6de9cd9a DN |
420 | an object is locally live at the start of the block (LIVEIN) |
421 | and the set of blocks where the object is defined (DEF_BLOCKS). | |
422 | ||
423 | Note: This routine augments the existing local livein information | |
424 | to include global livein (i.e., it modifies the underlying bitmap | |
425 | for LIVEIN). */ | |
426 | ||
5f240ec4 | 427 | void |
726a989a | 428 | compute_global_livein (bitmap livein ATTRIBUTE_UNUSED, bitmap def_blocks ATTRIBUTE_UNUSED) |
6de9cd9a DN |
429 | { |
430 | basic_block bb, *worklist, *tos; | |
3cd8c58a | 431 | unsigned i; |
87c476a2 | 432 | bitmap_iterator bi; |
6de9cd9a DN |
433 | |
434 | tos = worklist | |
0bca51f0 | 435 | = (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1)); |
6de9cd9a | 436 | |
87c476a2 | 437 | EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi) |
38635499 | 438 | *tos++ = BASIC_BLOCK (i); |
6de9cd9a DN |
439 | |
440 | /* Iterate until the worklist is empty. */ | |
441 | while (tos != worklist) | |
442 | { | |
443 | edge e; | |
628f6a4e | 444 | edge_iterator ei; |
6de9cd9a DN |
445 | |
446 | /* Pull a block off the worklist. */ | |
447 | bb = *--tos; | |
448 | ||
449 | /* For each predecessor block. */ | |
628f6a4e | 450 | FOR_EACH_EDGE (e, ei, bb->preds) |
6de9cd9a DN |
451 | { |
452 | basic_block pred = e->src; | |
453 | int pred_index = pred->index; | |
454 | ||
455 | /* None of this is necessary for the entry block. */ | |
456 | if (pred != ENTRY_BLOCK_PTR | |
457 | && ! bitmap_bit_p (livein, pred_index) | |
458 | && ! bitmap_bit_p (def_blocks, pred_index)) | |
459 | { | |
460 | *tos++ = pred; | |
461 | bitmap_set_bit (livein, pred_index); | |
462 | } | |
463 | } | |
464 | } | |
465 | ||
466 | free (worklist); | |
467 | } | |
468 | ||
469 | ||
95dd3097 ZD |
470 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
471 | all statements in basic block BB. */ | |
472 | ||
473 | static void | |
474 | initialize_flags_in_bb (basic_block bb) | |
475 | { | |
726a989a RB |
476 | gimple stmt; |
477 | gimple_stmt_iterator gsi; | |
95dd3097 | 478 | |
726a989a | 479 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 480 | { |
726a989a RB |
481 | gimple phi = gsi_stmt (gsi); |
482 | set_rewrite_uses (phi, false); | |
483 | set_register_defs (phi, false); | |
95dd3097 ZD |
484 | } |
485 | ||
726a989a | 486 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
95dd3097 | 487 | { |
726a989a RB |
488 | stmt = gsi_stmt (gsi); |
489 | ||
95dd3097 ZD |
490 | /* We are going to use the operand cache API, such as |
491 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
492 | cache for each statement should be up-to-date. */ | |
726a989a RB |
493 | gcc_assert (!gimple_modified_p (stmt)); |
494 | set_rewrite_uses (stmt, false); | |
495 | set_register_defs (stmt, false); | |
95dd3097 ZD |
496 | } |
497 | } | |
498 | ||
499 | /* Mark block BB as interesting for update_ssa. */ | |
500 | ||
501 | static void | |
502 | mark_block_for_update (basic_block bb) | |
503 | { | |
504 | gcc_assert (blocks_to_update != NULL); | |
f3cf730b | 505 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
95dd3097 | 506 | return; |
95dd3097 ZD |
507 | initialize_flags_in_bb (bb); |
508 | } | |
509 | ||
7256233c DN |
510 | /* Return the set of blocks where variable VAR is defined and the blocks |
511 | where VAR is live on entry (livein). If no entry is found in | |
512 | DEF_BLOCKS, a new one is created and returned. */ | |
6de9cd9a | 513 | |
7256233c DN |
514 | static inline struct def_blocks_d * |
515 | get_def_blocks_for (tree var) | |
6de9cd9a | 516 | { |
b4e209fd | 517 | struct def_blocks_d *db_p; |
6de9cd9a | 518 | |
b4e209fd RG |
519 | if (TREE_CODE (var) == SSA_NAME) |
520 | db_p = &get_ssa_name_ann (var)->def_blocks; | |
521 | else | |
522 | db_p = &get_var_info (var)->def_blocks; | |
523 | ||
524 | if (!db_p->def_blocks) | |
6de9cd9a | 525 | { |
b4e209fd RG |
526 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
527 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
528 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
a32b97a2 BB |
529 | } |
530 | ||
7256233c | 531 | return db_p; |
6de9cd9a DN |
532 | } |
533 | ||
7d5f9cc6 | 534 | |
5f240ec4 | 535 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
0bca51f0 | 536 | VAR is defined by a PHI node. */ |
6de9cd9a DN |
537 | |
538 | static void | |
0bca51f0 | 539 | set_def_block (tree var, basic_block bb, bool phi_p) |
6de9cd9a DN |
540 | { |
541 | struct def_blocks_d *db_p; | |
34eb8991 JL |
542 | enum need_phi_state state; |
543 | ||
5f240ec4 | 544 | state = get_phi_state (var); |
6de9cd9a DN |
545 | db_p = get_def_blocks_for (var); |
546 | ||
547 | /* Set the bit corresponding to the block where VAR is defined. */ | |
548 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
5f240ec4 ZD |
549 | if (phi_p) |
550 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
6de9cd9a | 551 | |
7256233c | 552 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
553 | |
554 | If we are in the UNKNOWN state, then this is the first definition | |
555 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
7256233c | 556 | we do not need a PHI node for this variable at this time (i.e., |
6de9cd9a DN |
557 | transition to NEED_PHI_STATE_NO). |
558 | ||
559 | If we are in any other state, then we either have multiple definitions | |
560 | of this variable occurring in different blocks or we saw a use of the | |
561 | variable which was not dominated by the block containing the | |
562 | definition(s). In this case we may need a PHI node, so enter | |
563 | state NEED_PHI_STATE_MAYBE. */ | |
564 | if (state == NEED_PHI_STATE_UNKNOWN) | |
5f240ec4 | 565 | set_phi_state (var, NEED_PHI_STATE_NO); |
6de9cd9a | 566 | else |
5f240ec4 | 567 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
568 | } |
569 | ||
570 | ||
571 | /* Mark block BB as having VAR live at the entry to BB. */ | |
572 | ||
573 | static void | |
574 | set_livein_block (tree var, basic_block bb) | |
575 | { | |
576 | struct def_blocks_d *db_p; | |
5f240ec4 | 577 | enum need_phi_state state = get_phi_state (var); |
6de9cd9a DN |
578 | |
579 | db_p = get_def_blocks_for (var); | |
580 | ||
581 | /* Set the bit corresponding to the block where VAR is live in. */ | |
582 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
583 | ||
7256233c | 584 | /* Keep track of whether or not we may need to insert PHI nodes. |
6de9cd9a DN |
585 | |
586 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
587 | by the single block containing the definition(s) of this variable. If | |
588 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
589 | NEED_PHI_STATE_MAYBE. */ | |
590 | if (state == NEED_PHI_STATE_NO) | |
591 | { | |
592 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
593 | ||
594 | if (def_block_index == -1 | |
595 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
596 | BASIC_BLOCK (def_block_index))) | |
5f240ec4 | 597 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
598 | } |
599 | else | |
5f240ec4 | 600 | set_phi_state (var, NEED_PHI_STATE_MAYBE); |
6de9cd9a DN |
601 | } |
602 | ||
603 | ||
0bca51f0 | 604 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
6de9cd9a | 605 | |
0bca51f0 DN |
606 | static inline bool |
607 | is_old_name (tree name) | |
608 | { | |
84d65814 | 609 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
610 | if (!new_ssa_names) |
611 | return false; | |
84d65814 | 612 | return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver); |
0bca51f0 DN |
613 | } |
614 | ||
615 | ||
616 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
34eb8991 | 617 | |
0bca51f0 DN |
618 | static inline bool |
619 | is_new_name (tree name) | |
620 | { | |
84d65814 | 621 | unsigned ver = SSA_NAME_VERSION (name); |
5006671f RG |
622 | if (!new_ssa_names) |
623 | return false; | |
84d65814 | 624 | return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver); |
6de9cd9a DN |
625 | } |
626 | ||
7256233c | 627 | |
82d6e6fc | 628 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
0bca51f0 DN |
629 | |
630 | static inline bitmap | |
82d6e6fc | 631 | names_replaced_by (tree new_tree) |
0bca51f0 | 632 | { |
891f2df6 | 633 | return get_ssa_name_ann (new_tree)->repl_set; |
0bca51f0 DN |
634 | } |
635 | ||
636 | ||
82d6e6fc | 637 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
0bca51f0 DN |
638 | |
639 | static inline void | |
82d6e6fc | 640 | add_to_repl_tbl (tree new_tree, tree old) |
0bca51f0 | 641 | { |
891f2df6 RG |
642 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
643 | if (!*set) | |
644 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
645 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
0bca51f0 DN |
646 | } |
647 | ||
648 | ||
82d6e6fc | 649 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
0bca51f0 DN |
650 | represents the set of names O_1 ... O_j replaced by N_i. This is |
651 | used by update_ssa and its helpers to introduce new SSA names in an | |
652 | already formed SSA web. */ | |
653 | ||
654 | static void | |
82d6e6fc | 655 | add_new_name_mapping (tree new_tree, tree old) |
0bca51f0 DN |
656 | { |
657 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
658 | ||
82d6e6fc KG |
659 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
660 | gcc_assert (new_tree != old && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
84d65814 | 661 | |
38635499 DN |
662 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
663 | caller may have created new names since the set was created. */ | |
664 | if (new_ssa_names->n_bits <= num_ssa_names - 1) | |
665 | { | |
666 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
667 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
668 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
0bca51f0 DN |
669 | } |
670 | ||
0bca51f0 | 671 | /* Update the REPL_TBL table. */ |
82d6e6fc | 672 | add_to_repl_tbl (new_tree, old); |
d00ad49b | 673 | |
0bca51f0 | 674 | /* If OLD had already been registered as a new name, then all the |
82d6e6fc | 675 | names that OLD replaces should also be replaced by NEW_TREE. */ |
0bca51f0 | 676 | if (is_new_name (old)) |
82d6e6fc | 677 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
0bca51f0 | 678 | |
82d6e6fc | 679 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
0bca51f0 | 680 | respectively. */ |
82d6e6fc | 681 | SET_BIT (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
0bca51f0 DN |
682 | SET_BIT (old_ssa_names, SSA_NAME_VERSION (old)); |
683 | ||
0bca51f0 | 684 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
d00ad49b | 685 | } |
6de9cd9a | 686 | |
6de9cd9a | 687 | |
7256233c DN |
688 | /* Call back for walk_dominator_tree used to collect definition sites |
689 | for every variable in the function. For every statement S in block | |
690 | BB: | |
6de9cd9a | 691 | |
f47c96aa | 692 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
ccf5c864 | 693 | KILLS. |
6de9cd9a | 694 | |
7256233c | 695 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
7b71de26 | 696 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
6de9cd9a | 697 | |
7256233c DN |
698 | This information is used to determine which variables are live |
699 | across block boundaries to reduce the number of PHI nodes | |
700 | we create. */ | |
6de9cd9a | 701 | |
7256233c | 702 | static void |
ccf5c864 | 703 | mark_def_sites (basic_block bb, gimple stmt, bitmap kills) |
7256233c | 704 | { |
726a989a | 705 | tree def; |
7256233c | 706 | use_operand_p use_p; |
7256233c DN |
707 | ssa_op_iter iter; |
708 | ||
726a989a RB |
709 | /* Since this is the first time that we rewrite the program into SSA |
710 | form, force an operand scan on every statement. */ | |
726a989a | 711 | update_stmt (stmt); |
7256233c | 712 | |
95dd3097 | 713 | gcc_assert (blocks_to_update == NULL); |
726a989a RB |
714 | set_register_defs (stmt, false); |
715 | set_rewrite_uses (stmt, false); | |
7256233c | 716 | |
b5b8b0ac | 717 | if (is_gimple_debug (stmt)) |
ddb555ed JJ |
718 | { |
719 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
720 | { | |
721 | tree sym = USE_FROM_PTR (use_p); | |
722 | gcc_assert (DECL_P (sym)); | |
723 | set_rewrite_uses (stmt, true); | |
724 | } | |
725 | if (rewrite_uses_p (stmt)) | |
726 | SET_BIT (interesting_blocks, bb->index); | |
727 | return; | |
728 | } | |
b5b8b0ac | 729 | |
7256233c DN |
730 | /* If a variable is used before being set, then the variable is live |
731 | across a block boundary, so mark it live-on-entry to BB. */ | |
39c58b3a | 732 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
7256233c | 733 | { |
0bca51f0 DN |
734 | tree sym = USE_FROM_PTR (use_p); |
735 | gcc_assert (DECL_P (sym)); | |
a3648cfc | 736 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
0bca51f0 | 737 | set_livein_block (sym, bb); |
726a989a | 738 | set_rewrite_uses (stmt, true); |
7256233c | 739 | } |
b8698a0f | 740 | |
38635499 DN |
741 | /* Now process the defs. Mark BB as the definition block and add |
742 | each def to the set of killed symbols. */ | |
39c58b3a | 743 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
7256233c | 744 | { |
0bca51f0 DN |
745 | gcc_assert (DECL_P (def)); |
746 | set_def_block (def, bb, false); | |
a3648cfc | 747 | bitmap_set_bit (kills, DECL_UID (def)); |
726a989a | 748 | set_register_defs (stmt, true); |
7256233c | 749 | } |
0bca51f0 DN |
750 | |
751 | /* If we found the statement interesting then also mark the block BB | |
752 | as interesting. */ | |
726a989a | 753 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
ccf5c864 | 754 | SET_BIT (interesting_blocks, bb->index); |
7256233c DN |
755 | } |
756 | ||
f074ff6c ZD |
757 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
758 | in the dfs numbering of the dominance tree. */ | |
759 | ||
760 | struct dom_dfsnum | |
761 | { | |
762 | /* Basic block whose index this entry corresponds to. */ | |
763 | unsigned bb_index; | |
764 | ||
765 | /* The dfs number of this node. */ | |
766 | unsigned dfs_num; | |
767 | }; | |
768 | ||
769 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
770 | for qsort. */ | |
771 | ||
772 | static int | |
773 | cmp_dfsnum (const void *a, const void *b) | |
774 | { | |
3d9a9f94 KG |
775 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
776 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f074ff6c ZD |
777 | |
778 | return (int) da->dfs_num - (int) db->dfs_num; | |
779 | } | |
780 | ||
781 | /* Among the intervals starting at the N points specified in DEFS, find | |
782 | the one that contains S, and return its bb_index. */ | |
783 | ||
784 | static unsigned | |
785 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
786 | { | |
787 | unsigned f = 0, t = n, m; | |
788 | ||
789 | while (t > f + 1) | |
790 | { | |
791 | m = (f + t) / 2; | |
792 | if (defs[m].dfs_num <= s) | |
793 | f = m; | |
794 | else | |
795 | t = m; | |
796 | } | |
797 | ||
798 | return defs[f].bb_index; | |
799 | } | |
800 | ||
801 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
802 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
803 | ||
804 | static void | |
805 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
806 | { | |
807 | VEC(int, heap) *worklist; | |
808 | bitmap_iterator bi; | |
809 | unsigned i, b, p, u, top; | |
810 | bitmap live_phis; | |
811 | basic_block def_bb, use_bb; | |
812 | edge e; | |
813 | edge_iterator ei; | |
814 | bitmap to_remove; | |
815 | struct dom_dfsnum *defs; | |
816 | unsigned n_defs, adef; | |
817 | ||
818 | if (bitmap_empty_p (uses)) | |
819 | { | |
820 | bitmap_clear (phis); | |
821 | return; | |
822 | } | |
823 | ||
824 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
825 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
826 | to_remove = BITMAP_ALLOC (NULL); | |
827 | bitmap_and_compl (to_remove, kills, uses); | |
828 | bitmap_and_compl_into (phis, to_remove); | |
829 | if (bitmap_empty_p (phis)) | |
830 | { | |
831 | BITMAP_FREE (to_remove); | |
832 | return; | |
833 | } | |
834 | ||
835 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
836 | liveness information, as that may be linear in the size of CFG, and if | |
837 | there are lot of different variables to rewrite, this may lead to quadratic | |
838 | behavior. | |
839 | ||
840 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
841 | then for each of them find the nearest def that dominates them. If this | |
842 | def is a phi node, we mark it live, and if it was not live before, we | |
843 | add the predecessors of its basic block to the worklist. | |
b8698a0f | 844 | |
f074ff6c ZD |
845 | To quickly locate the nearest def that dominates use, we use dfs numbering |
846 | of the dominance tree (that is already available in order to speed up | |
847 | queries). For each def, we have the interval given by the dfs number on | |
848 | entry to and on exit from the corresponding subtree in the dominance tree. | |
849 | The nearest dominator for a given use is the smallest of these intervals | |
850 | that contains entry and exit dfs numbers for the basic block with the use. | |
851 | If we store the bounds for all the uses to an array and sort it, we can | |
852 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
853 | bitmap_ior (to_remove, kills, phis); | |
854 | n_defs = bitmap_count_bits (to_remove); | |
855 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
856 | defs[0].bb_index = 1; | |
857 | defs[0].dfs_num = 0; | |
858 | adef = 1; | |
859 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
860 | { | |
861 | def_bb = BASIC_BLOCK (i); | |
862 | defs[adef].bb_index = i; | |
863 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
864 | defs[adef + 1].bb_index = i; | |
865 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
866 | adef += 2; | |
867 | } | |
868 | BITMAP_FREE (to_remove); | |
869 | gcc_assert (adef == 2 * n_defs + 1); | |
870 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
871 | gcc_assert (defs[0].bb_index == 1); | |
872 | ||
873 | /* Now each DEFS entry contains the number of the basic block to that the | |
874 | dfs number corresponds. Change them to the number of basic block that | |
875 | corresponds to the interval following the dfs number. Also, for the | |
876 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
877 | to the start of the following interval, not to the end of the current | |
878 | one). We use WORKLIST as a stack. */ | |
879 | worklist = VEC_alloc (int, heap, n_defs + 1); | |
880 | VEC_quick_push (int, worklist, 1); | |
881 | top = 1; | |
882 | n_defs = 1; | |
883 | for (i = 1; i < adef; i++) | |
884 | { | |
885 | b = defs[i].bb_index; | |
886 | if (b == top) | |
887 | { | |
888 | /* This is a closing element. Interval corresponding to the top | |
889 | of the stack after removing it follows. */ | |
890 | VEC_pop (int, worklist); | |
891 | top = VEC_index (int, worklist, VEC_length (int, worklist) - 1); | |
892 | defs[n_defs].bb_index = top; | |
893 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
894 | } | |
895 | else | |
896 | { | |
897 | /* Opening element. Nothing to do, just push it to the stack and move | |
898 | it to the correct position. */ | |
899 | defs[n_defs].bb_index = defs[i].bb_index; | |
900 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
901 | VEC_quick_push (int, worklist, b); | |
902 | top = b; | |
903 | } | |
904 | ||
905 | /* If this interval starts at the same point as the previous one, cancel | |
906 | the previous one. */ | |
907 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
908 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
909 | else | |
910 | n_defs++; | |
911 | } | |
912 | VEC_pop (int, worklist); | |
913 | gcc_assert (VEC_empty (int, worklist)); | |
914 | ||
915 | /* Now process the uses. */ | |
916 | live_phis = BITMAP_ALLOC (NULL); | |
917 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
918 | { | |
919 | VEC_safe_push (int, heap, worklist, i); | |
920 | } | |
921 | ||
922 | while (!VEC_empty (int, worklist)) | |
923 | { | |
924 | b = VEC_pop (int, worklist); | |
925 | if (b == ENTRY_BLOCK) | |
926 | continue; | |
927 | ||
928 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
929 | find the def that dominates the immediate dominator of USE_BB | |
930 | (the kill in USE_BB does not dominate the use). */ | |
931 | if (bitmap_bit_p (phis, b)) | |
932 | p = b; | |
933 | else | |
934 | { | |
935 | use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b)); | |
936 | p = find_dfsnum_interval (defs, n_defs, | |
937 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
938 | if (!bitmap_bit_p (phis, p)) | |
939 | continue; | |
940 | } | |
941 | ||
942 | /* If the phi node is already live, there is nothing to do. */ | |
fcaa4ca4 | 943 | if (!bitmap_set_bit (live_phis, p)) |
f074ff6c ZD |
944 | continue; |
945 | ||
fcaa4ca4 | 946 | /* Add the new uses to the worklist. */ |
f074ff6c ZD |
947 | def_bb = BASIC_BLOCK (p); |
948 | FOR_EACH_EDGE (e, ei, def_bb->preds) | |
949 | { | |
950 | u = e->src->index; | |
951 | if (bitmap_bit_p (uses, u)) | |
952 | continue; | |
953 | ||
1e5787ef ZD |
954 | /* In case there is a kill directly in the use block, do not record |
955 | the use (this is also necessary for correctness, as we assume that | |
956 | uses dominated by a def directly in their block have been filtered | |
957 | out before). */ | |
958 | if (bitmap_bit_p (kills, u)) | |
959 | continue; | |
960 | ||
f074ff6c ZD |
961 | bitmap_set_bit (uses, u); |
962 | VEC_safe_push (int, heap, worklist, u); | |
963 | } | |
964 | } | |
965 | ||
966 | VEC_free (int, heap, worklist); | |
967 | bitmap_copy (phis, live_phis); | |
968 | BITMAP_FREE (live_phis); | |
969 | free (defs); | |
970 | } | |
7256233c | 971 | |
7256233c DN |
972 | /* Return the set of blocks where variable VAR is defined and the blocks |
973 | where VAR is live on entry (livein). Return NULL, if no entry is | |
974 | found in DEF_BLOCKS. */ | |
975 | ||
976 | static inline struct def_blocks_d * | |
977 | find_def_blocks_for (tree var) | |
978 | { | |
b4e209fd RG |
979 | def_blocks_p p; |
980 | if (TREE_CODE (var) == SSA_NAME) | |
981 | p = &get_ssa_name_ann (var)->def_blocks; | |
982 | else | |
983 | p = &get_var_info (var)->def_blocks; | |
984 | if (!p->def_blocks) | |
985 | return NULL; | |
986 | return p; | |
7256233c DN |
987 | } |
988 | ||
989 | ||
2ce79879 ZD |
990 | /* Marks phi node PHI in basic block BB for rewrite. */ |
991 | ||
992 | static void | |
726a989a | 993 | mark_phi_for_rewrite (basic_block bb, gimple phi) |
2ce79879 | 994 | { |
726a989a | 995 | gimple_vec phis; |
2ce79879 ZD |
996 | unsigned i, idx = bb->index; |
997 | ||
726a989a | 998 | if (rewrite_uses_p (phi)) |
2ce79879 | 999 | return; |
38635499 | 1000 | |
726a989a | 1001 | set_rewrite_uses (phi, true); |
2ce79879 ZD |
1002 | |
1003 | if (!blocks_with_phis_to_rewrite) | |
1004 | return; | |
1005 | ||
1006 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
726a989a RB |
1007 | VEC_reserve (gimple_vec, heap, phis_to_rewrite, last_basic_block + 1); |
1008 | for (i = VEC_length (gimple_vec, phis_to_rewrite); i <= idx; i++) | |
1009 | VEC_quick_push (gimple_vec, phis_to_rewrite, NULL); | |
2ce79879 | 1010 | |
726a989a | 1011 | phis = VEC_index (gimple_vec, phis_to_rewrite, idx); |
2ce79879 | 1012 | if (!phis) |
726a989a | 1013 | phis = VEC_alloc (gimple, heap, 10); |
2ce79879 | 1014 | |
726a989a RB |
1015 | VEC_safe_push (gimple, heap, phis, phi); |
1016 | VEC_replace (gimple_vec, phis_to_rewrite, idx, phis); | |
2ce79879 ZD |
1017 | } |
1018 | ||
7256233c | 1019 | /* Insert PHI nodes for variable VAR using the iterated dominance |
0bca51f0 | 1020 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
38635499 DN |
1021 | function assumes that the caller is incrementally updating the |
1022 | existing SSA form, in which case VAR may be an SSA name instead of | |
1023 | a symbol. | |
0bca51f0 DN |
1024 | |
1025 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
1026 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
1027 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
7256233c DN |
1028 | |
1029 | static void | |
0bca51f0 | 1030 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
7256233c DN |
1031 | { |
1032 | unsigned bb_index; | |
1033 | edge e; | |
726a989a | 1034 | gimple phi; |
7256233c DN |
1035 | basic_block bb; |
1036 | bitmap_iterator bi; | |
1037 | struct def_blocks_d *def_map; | |
1038 | ||
1039 | def_map = find_def_blocks_for (var); | |
0bca51f0 | 1040 | gcc_assert (def_map); |
7256233c DN |
1041 | |
1042 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
1043 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
1044 | ||
f074ff6c ZD |
1045 | /* Remove obviously useless phi nodes. */ |
1046 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
1047 | def_map->livein_blocks); | |
7256233c DN |
1048 | |
1049 | /* And insert the PHI nodes. */ | |
f074ff6c | 1050 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
7256233c DN |
1051 | { |
1052 | bb = BASIC_BLOCK (bb_index); | |
95dd3097 ZD |
1053 | if (update_p) |
1054 | mark_block_for_update (bb); | |
7256233c | 1055 | |
726a989a | 1056 | phi = NULL; |
38635499 DN |
1057 | |
1058 | if (TREE_CODE (var) == SSA_NAME) | |
7256233c | 1059 | { |
84d65814 DN |
1060 | /* If we are rewriting SSA names, create the LHS of the PHI |
1061 | node by duplicating VAR. This is useful in the case of | |
1062 | pointers, to also duplicate pointer attributes (alias | |
1063 | information, in particular). */ | |
7256233c | 1064 | edge_iterator ei; |
84d65814 | 1065 | tree new_lhs; |
0bca51f0 | 1066 | |
38635499 | 1067 | gcc_assert (update_p); |
84d65814 | 1068 | phi = create_phi_node (var, bb); |
38635499 | 1069 | |
84d65814 | 1070 | new_lhs = duplicate_ssa_name (var, phi); |
726a989a | 1071 | gimple_phi_set_result (phi, new_lhs); |
84d65814 | 1072 | add_new_name_mapping (new_lhs, var); |
0bca51f0 DN |
1073 | |
1074 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1075 | every argument so that rewrite_update_phi_arguments knows | |
1076 | which name is this PHI node replacing. If VAR is a | |
1077 | symbol marked for renaming, this is not necessary, the | |
1078 | renamer will use the symbol on the LHS to get its | |
1079 | reaching definition. */ | |
7256233c | 1080 | FOR_EACH_EDGE (e, ei, bb->preds) |
9e227d60 | 1081 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
7256233c | 1082 | } |
84d65814 DN |
1083 | else |
1084 | { | |
b5b8b0ac | 1085 | tree tracked_var; |
3a56edc7 | 1086 | |
e24c4814 SB |
1087 | gcc_assert (DECL_P (var)); |
1088 | phi = create_phi_node (var, bb); | |
3a56edc7 AO |
1089 | |
1090 | tracked_var = target_for_debug_bind (var); | |
1091 | if (tracked_var) | |
b5b8b0ac AO |
1092 | { |
1093 | gimple note = gimple_build_debug_bind (tracked_var, | |
1094 | PHI_RESULT (phi), | |
1095 | phi); | |
1096 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1097 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1098 | } | |
84d65814 | 1099 | } |
0bca51f0 DN |
1100 | |
1101 | /* Mark this PHI node as interesting for update_ssa. */ | |
726a989a | 1102 | set_register_defs (phi, true); |
2ce79879 | 1103 | mark_phi_for_rewrite (bb, phi); |
7256233c DN |
1104 | } |
1105 | } | |
1106 | ||
b4e209fd | 1107 | /* Sort var_infos after DECL_UID of their var. */ |
d9ed2fbd RG |
1108 | |
1109 | static int | |
b4e209fd | 1110 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
d9ed2fbd | 1111 | { |
b4e209fd RG |
1112 | const struct var_info_d *defa = *(struct var_info_d * const *)a; |
1113 | const struct var_info_d *defb = *(struct var_info_d * const *)b; | |
d9ed2fbd RG |
1114 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1115 | return -1; | |
1116 | else | |
1117 | return 1; | |
1118 | } | |
7256233c | 1119 | |
7256233c DN |
1120 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1121 | definitions. DFS contains the dominance frontier information for | |
38635499 | 1122 | the flowgraph. */ |
7256233c DN |
1123 | |
1124 | static void | |
0fc555fb | 1125 | insert_phi_nodes (bitmap_head *dfs) |
7256233c | 1126 | { |
d9ed2fbd RG |
1127 | htab_iterator hi; |
1128 | unsigned i; | |
b4e209fd RG |
1129 | var_info_p info; |
1130 | VEC(var_info_p,heap) *vars; | |
7256233c DN |
1131 | |
1132 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
b8698a0f | 1133 | |
b4e209fd RG |
1134 | vars = VEC_alloc (var_info_p, heap, htab_elements (var_infos)); |
1135 | FOR_EACH_HTAB_ELEMENT (var_infos, info, var_info_p, hi) | |
1136 | if (info->need_phi_state != NEED_PHI_STATE_NO) | |
1137 | VEC_quick_push (var_info_p, vars, info); | |
d9ed2fbd | 1138 | |
e68c7b43 RG |
1139 | /* Do two stages to avoid code generation differences for UID |
1140 | differences but no UID ordering differences. */ | |
b4e209fd | 1141 | VEC_qsort (var_info_p, vars, insert_phi_nodes_compare_var_infos); |
e68c7b43 | 1142 | |
b4e209fd | 1143 | FOR_EACH_VEC_ELT (var_info_p, vars, i, info) |
5f240ec4 | 1144 | { |
b4e209fd RG |
1145 | bitmap idf = compute_idf (info->def_blocks.def_blocks, dfs); |
1146 | insert_phi_nodes_for (info->var, idf, false); | |
e68c7b43 RG |
1147 | BITMAP_FREE (idf); |
1148 | } | |
1149 | ||
b4e209fd | 1150 | VEC_free(var_info_p, heap, vars); |
e68c7b43 | 1151 | |
6de9cd9a DN |
1152 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1153 | } | |
1154 | ||
1155 | ||
38635499 DN |
1156 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1157 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
7256233c | 1158 | |
cfaab3a9 | 1159 | static void |
38635499 | 1160 | register_new_def (tree def, tree sym) |
7256233c | 1161 | { |
7256233c | 1162 | tree currdef; |
b8698a0f | 1163 | |
7256233c DN |
1164 | /* If this variable is set in a single basic block and all uses are |
1165 | dominated by the set(s) in that single basic block, then there is | |
1166 | no reason to record anything for this variable in the block local | |
1167 | definition stacks. Doing so just wastes time and memory. | |
1168 | ||
1169 | This is the same test to prune the set of variables which may | |
1170 | need PHI nodes. So we just use that information since it's already | |
1171 | computed and available for us to use. */ | |
38635499 | 1172 | if (get_phi_state (sym) == NEED_PHI_STATE_NO) |
7256233c | 1173 | { |
38635499 | 1174 | set_current_def (sym, def); |
7256233c DN |
1175 | return; |
1176 | } | |
1177 | ||
38635499 | 1178 | currdef = get_current_def (sym); |
7256233c | 1179 | |
38635499 DN |
1180 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1181 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1182 | in the stack so that we know which symbol is being defined by | |
1183 | this SSA name when we unwind the stack. */ | |
1184 | if (currdef && !is_gimple_reg (sym)) | |
1185 | VEC_safe_push (tree, heap, block_defs_stack, sym); | |
7256233c | 1186 | |
38635499 DN |
1187 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1188 | stack is later used by the dominator tree callbacks to restore | |
1189 | the reaching definitions for all the variables defined in the | |
1190 | block after a recursive visit to all its immediately dominated | |
1191 | blocks. If there is no current reaching definition, then just | |
1192 | record the underlying _DECL node. */ | |
1193 | VEC_safe_push (tree, heap, block_defs_stack, currdef ? currdef : sym); | |
1194 | ||
1195 | /* Set the current reaching definition for SYM to be DEF. */ | |
1196 | set_current_def (sym, def); | |
7256233c DN |
1197 | } |
1198 | ||
1199 | ||
6de9cd9a DN |
1200 | /* Perform a depth-first traversal of the dominator tree looking for |
1201 | variables to rename. BB is the block where to start searching. | |
1202 | Renaming is a five step process: | |
1203 | ||
1204 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1205 | registered as the current definition for the corresponding variable. | |
1206 | ||
1207 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1208 | rewritten with their corresponding reaching definition. DEF and | |
1209 | VDEF targets are registered as new definitions. | |
b8698a0f | 1210 | |
6de9cd9a DN |
1211 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1212 | argument corresponding to BB is replaced with its current reaching | |
1213 | definition. | |
1214 | ||
1215 | 4- Recursively rewrite every dominator child block of BB. | |
1216 | ||
1217 | 5- Restore (in reverse order) the current reaching definition for every | |
1218 | new definition introduced in this block. This is done so that when | |
1219 | we return from the recursive call, all the current reaching | |
1220 | definitions are restored to the names that were valid in the | |
1221 | dominator parent of BB. */ | |
1222 | ||
7256233c | 1223 | /* Return the current definition for variable VAR. If none is found, |
38635499 | 1224 | create a new SSA name to act as the zeroth definition for VAR. */ |
5f240ec4 | 1225 | |
7256233c DN |
1226 | static tree |
1227 | get_reaching_def (tree var) | |
1228 | { | |
38635499 | 1229 | tree currdef; |
b8698a0f | 1230 | |
7256233c | 1231 | /* Lookup the current reaching definition for VAR. */ |
38635499 | 1232 | currdef = get_current_def (var); |
5f240ec4 | 1233 | |
7256233c DN |
1234 | /* If there is no reaching definition for VAR, create and register a |
1235 | default definition for it (if needed). */ | |
38635499 | 1236 | if (currdef == NULL_TREE) |
7256233c | 1237 | { |
38635499 | 1238 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
32244553 | 1239 | currdef = get_or_create_ssa_default_def (cfun, sym); |
38635499 | 1240 | set_current_def (var, currdef); |
7256233c DN |
1241 | } |
1242 | ||
1243 | /* Return the current reaching definition for VAR, or the default | |
1244 | definition, if we had to create one. */ | |
38635499 | 1245 | return currdef; |
7256233c DN |
1246 | } |
1247 | ||
1248 | ||
ddb555ed JJ |
1249 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1250 | ||
1251 | static void | |
1252 | rewrite_debug_stmt_uses (gimple stmt) | |
1253 | { | |
1254 | use_operand_p use_p; | |
1255 | ssa_op_iter iter; | |
1256 | bool update = false; | |
1257 | ||
1258 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1259 | { | |
5f564b8f | 1260 | tree var = USE_FROM_PTR (use_p), def; |
ddb555ed | 1261 | gcc_assert (DECL_P (var)); |
5f564b8f MM |
1262 | def = get_current_def (var); |
1263 | if (!def) | |
ddb555ed JJ |
1264 | { |
1265 | if (TREE_CODE (var) == PARM_DECL && single_succ_p (ENTRY_BLOCK_PTR)) | |
1266 | { | |
1267 | gimple_stmt_iterator gsi | |
1268 | = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1269 | int lim; | |
1270 | /* Search a few source bind stmts at the start of first bb to | |
1271 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1272 | for (lim = 32; | |
1273 | !gsi_end_p (gsi) && lim > 0; | |
1274 | gsi_next (&gsi), lim--) | |
1275 | { | |
1276 | gimple gstmt = gsi_stmt (gsi); | |
1277 | if (!gimple_debug_source_bind_p (gstmt)) | |
1278 | break; | |
1279 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1280 | { | |
1281 | def = gimple_debug_source_bind_get_var (gstmt); | |
1282 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1283 | break; | |
1284 | else | |
1285 | def = NULL_TREE; | |
1286 | } | |
1287 | } | |
1288 | /* If not, add a new source bind stmt. */ | |
1289 | if (def == NULL_TREE) | |
1290 | { | |
1291 | gimple def_temp; | |
1292 | def = make_node (DEBUG_EXPR_DECL); | |
1293 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1294 | DECL_ARTIFICIAL (def) = 1; | |
1295 | TREE_TYPE (def) = TREE_TYPE (var); | |
1296 | DECL_MODE (def) = DECL_MODE (var); | |
1297 | gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR)); | |
1298 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); | |
1299 | } | |
1300 | update = true; | |
1301 | } | |
1302 | } | |
1303 | else | |
15923c25 | 1304 | { |
15923c25 | 1305 | /* Check if get_current_def can be trusted. */ |
5f564b8f MM |
1306 | basic_block bb = gimple_bb (stmt); |
1307 | basic_block def_bb | |
1308 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1309 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1310 | ||
1311 | /* If definition is in current bb, it is fine. */ | |
1312 | if (bb == def_bb) | |
1313 | ; | |
1314 | /* If definition bb doesn't dominate the current bb, | |
1315 | it can't be used. */ | |
1316 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1317 | def = NULL; | |
1318 | /* If there is just one definition and dominates the current | |
1319 | bb, it is fine. */ | |
1320 | else if (get_phi_state (var) == NEED_PHI_STATE_NO) | |
1321 | ; | |
1322 | else | |
15923c25 | 1323 | { |
5f564b8f | 1324 | struct def_blocks_d *db_p = get_def_blocks_for (var); |
15923c25 | 1325 | |
5f564b8f MM |
1326 | /* If there are some non-debug uses in the current bb, |
1327 | it is fine. */ | |
1328 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
15923c25 | 1329 | ; |
5f564b8f | 1330 | /* Otherwise give up for now. */ |
15923c25 | 1331 | else |
5f564b8f | 1332 | def = NULL; |
15923c25 JJ |
1333 | } |
1334 | } | |
ddb555ed JJ |
1335 | if (def == NULL) |
1336 | { | |
1337 | gimple_debug_bind_reset_value (stmt); | |
1338 | update_stmt (stmt); | |
1339 | return; | |
1340 | } | |
1341 | SET_USE (use_p, def); | |
1342 | } | |
1343 | if (update) | |
1344 | update_stmt (stmt); | |
1345 | } | |
1346 | ||
7256233c DN |
1347 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1348 | the block with its immediate reaching definitions. Update the current | |
1349 | definition of a variable when a new real or virtual definition is found. */ | |
5f240ec4 ZD |
1350 | |
1351 | static void | |
b5b8b0ac | 1352 | rewrite_stmt (gimple_stmt_iterator si) |
5f240ec4 | 1353 | { |
7256233c DN |
1354 | use_operand_p use_p; |
1355 | def_operand_p def_p; | |
1356 | ssa_op_iter iter; | |
b5b8b0ac | 1357 | gimple stmt = gsi_stmt (si); |
7256233c | 1358 | |
7256233c DN |
1359 | /* If mark_def_sites decided that we don't need to rewrite this |
1360 | statement, ignore it. */ | |
95dd3097 | 1361 | gcc_assert (blocks_to_update == NULL); |
726a989a | 1362 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
7256233c | 1363 | return; |
5f240ec4 ZD |
1364 | |
1365 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
7256233c DN |
1366 | { |
1367 | fprintf (dump_file, "Renaming statement "); | |
726a989a | 1368 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
7256233c DN |
1369 | fprintf (dump_file, "\n"); |
1370 | } | |
5f240ec4 | 1371 | |
38635499 | 1372 | /* Step 1. Rewrite USES in the statement. */ |
726a989a | 1373 | if (rewrite_uses_p (stmt)) |
ddb555ed JJ |
1374 | { |
1375 | if (is_gimple_debug (stmt)) | |
1376 | rewrite_debug_stmt_uses (stmt); | |
1377 | else | |
39c58b3a | 1378 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
ddb555ed JJ |
1379 | { |
1380 | tree var = USE_FROM_PTR (use_p); | |
1381 | gcc_assert (DECL_P (var)); | |
1382 | SET_USE (use_p, get_reaching_def (var)); | |
1383 | } | |
1384 | } | |
5f240ec4 | 1385 | |
38635499 | 1386 | /* Step 2. Register the statement's DEF operands. */ |
726a989a | 1387 | if (register_defs_p (stmt)) |
39c58b3a | 1388 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
0bca51f0 DN |
1389 | { |
1390 | tree var = DEF_FROM_PTR (def_p); | |
b5b8b0ac AO |
1391 | tree name = make_ssa_name (var, stmt); |
1392 | tree tracked_var; | |
0bca51f0 | 1393 | gcc_assert (DECL_P (var)); |
b5b8b0ac | 1394 | SET_DEF (def_p, name); |
38635499 | 1395 | register_new_def (DEF_FROM_PTR (def_p), var); |
b5b8b0ac AO |
1396 | |
1397 | tracked_var = target_for_debug_bind (var); | |
1398 | if (tracked_var) | |
1399 | { | |
1400 | gimple note = gimple_build_debug_bind (tracked_var, name, stmt); | |
1401 | gsi_insert_after (&si, note, GSI_SAME_STMT); | |
1402 | } | |
0bca51f0 | 1403 | } |
5f240ec4 | 1404 | } |
6de9cd9a | 1405 | |
7256233c | 1406 | |
6de9cd9a DN |
1407 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1408 | PHI nodes. For every PHI node found, add a new argument containing the | |
1409 | current reaching definition for the variable and the edge through which | |
471854f8 | 1410 | that definition is reaching the PHI node. */ |
6de9cd9a DN |
1411 | |
1412 | static void | |
ccf5c864 | 1413 | rewrite_add_phi_arguments (basic_block bb) |
6de9cd9a DN |
1414 | { |
1415 | edge e; | |
628f6a4e | 1416 | edge_iterator ei; |
6de9cd9a | 1417 | |
628f6a4e | 1418 | FOR_EACH_EDGE (e, ei, bb->succs) |
6de9cd9a | 1419 | { |
726a989a RB |
1420 | gimple phi; |
1421 | gimple_stmt_iterator gsi; | |
6de9cd9a | 1422 | |
726a989a RB |
1423 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1424 | gsi_next (&gsi)) | |
6de9cd9a DN |
1425 | { |
1426 | tree currdef; | |
f5045c96 AM |
1427 | gimple stmt; |
1428 | ||
726a989a RB |
1429 | phi = gsi_stmt (gsi); |
1430 | currdef = get_reaching_def (SSA_NAME_VAR (gimple_phi_result (phi))); | |
f5045c96 | 1431 | stmt = SSA_NAME_DEF_STMT (currdef); |
9e227d60 | 1432 | add_phi_arg (phi, currdef, e, gimple_location (stmt)); |
6de9cd9a DN |
1433 | } |
1434 | } | |
1435 | } | |
1436 | ||
ccf5c864 PB |
1437 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1438 | of reaching definitions for new SSA names produced in this block | |
1439 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1440 | block. */ | |
1441 | ||
1442 | static void | |
1443 | rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
1444 | basic_block bb) | |
1445 | { | |
ccf5c864 PB |
1446 | gimple_stmt_iterator gsi; |
1447 | ||
1448 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1449 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1450 | ||
1451 | /* Mark the unwind point for this block. */ | |
1452 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
1453 | ||
1454 | /* Step 1. Register new definitions for every PHI node in the block. | |
1455 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1456 | node introduces a new version for the associated variable. */ | |
1457 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1458 | { | |
39c58b3a | 1459 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
ccf5c864 PB |
1460 | register_new_def (result, SSA_NAME_VAR (result)); |
1461 | } | |
1462 | ||
1463 | /* Step 2. Rewrite every variable used in each statement in the block | |
1464 | with its immediate reaching definitions. Update the current definition | |
1465 | of a variable when a new real or virtual definition is found. */ | |
1466 | if (TEST_BIT (interesting_blocks, bb->index)) | |
1467 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
b5b8b0ac | 1468 | rewrite_stmt (gsi); |
ccf5c864 PB |
1469 | |
1470 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1471 | For every PHI node found, add a new argument containing the current | |
1472 | reaching definition for the variable and the edge through which that | |
1473 | definition is reaching the PHI node. */ | |
1474 | rewrite_add_phi_arguments (bb); | |
1475 | } | |
1476 | ||
1477 | ||
7256233c | 1478 | |
38635499 DN |
1479 | /* Called after visiting all the statements in basic block BB and all |
1480 | of its dominator children. Restore CURRDEFS to its original value. */ | |
6de9cd9a DN |
1481 | |
1482 | static void | |
ccf5c864 PB |
1483 | rewrite_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1484 | basic_block bb ATTRIBUTE_UNUSED) | |
6de9cd9a | 1485 | { |
9fae925b | 1486 | /* Restore CURRDEFS to its original state. */ |
d4e6fecb | 1487 | while (VEC_length (tree, block_defs_stack) > 0) |
6de9cd9a | 1488 | { |
d4e6fecb | 1489 | tree tmp = VEC_pop (tree, block_defs_stack); |
6de9cd9a DN |
1490 | tree saved_def, var; |
1491 | ||
9fae925b JL |
1492 | if (tmp == NULL_TREE) |
1493 | break; | |
1494 | ||
6de9cd9a DN |
1495 | if (TREE_CODE (tmp) == SSA_NAME) |
1496 | { | |
38635499 DN |
1497 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1498 | current definition of its underlying variable. Note that | |
1499 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1500 | being defined is stored in the next slot in the stack. | |
1501 | This mechanism is needed because an SSA name for a | |
1502 | non-register symbol may be the definition for more than | |
1503 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
6de9cd9a DN |
1504 | saved_def = tmp; |
1505 | var = SSA_NAME_VAR (saved_def); | |
38635499 DN |
1506 | if (!is_gimple_reg (var)) |
1507 | var = VEC_pop (tree, block_defs_stack); | |
6de9cd9a DN |
1508 | } |
1509 | else | |
1510 | { | |
38635499 DN |
1511 | /* If we recorded anything else, it must have been a _DECL |
1512 | node and its current reaching definition must have been | |
1513 | NULL. */ | |
6de9cd9a DN |
1514 | saved_def = NULL; |
1515 | var = tmp; | |
1516 | } | |
b8698a0f | 1517 | |
5f240ec4 | 1518 | set_current_def (var, saved_def); |
6de9cd9a DN |
1519 | } |
1520 | } | |
1521 | ||
1522 | ||
38635499 DN |
1523 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1524 | ||
1525 | void | |
1526 | dump_decl_set (FILE *file, bitmap set) | |
1527 | { | |
1528 | if (set) | |
1529 | { | |
3b302421 RG |
1530 | bitmap_iterator bi; |
1531 | unsigned i; | |
38635499 DN |
1532 | |
1533 | fprintf (file, "{ "); | |
1534 | ||
3b302421 | 1535 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) |
38635499 | 1536 | { |
46eb666a | 1537 | fprintf (file, "D.%u", i); |
38635499 DN |
1538 | fprintf (file, " "); |
1539 | } | |
1540 | ||
5006671f | 1541 | fprintf (file, "}"); |
38635499 DN |
1542 | } |
1543 | else | |
5006671f | 1544 | fprintf (file, "NIL"); |
38635499 DN |
1545 | } |
1546 | ||
1547 | ||
1548 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ | |
1549 | ||
24e47c76 | 1550 | DEBUG_FUNCTION void |
38635499 DN |
1551 | debug_decl_set (bitmap set) |
1552 | { | |
1553 | dump_decl_set (stderr, set); | |
5006671f | 1554 | fprintf (stderr, "\n"); |
38635499 DN |
1555 | } |
1556 | ||
1557 | ||
1558 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1559 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1560 | dumped. New levels are created when the dominator tree traversal | |
1561 | used for renaming enters a new sub-tree. */ | |
1562 | ||
1563 | void | |
1564 | dump_defs_stack (FILE *file, int n) | |
1565 | { | |
1566 | int i, j; | |
1567 | ||
1568 | fprintf (file, "\n\nRenaming stack"); | |
1569 | if (n > 0) | |
1570 | fprintf (file, " (up to %d levels)", n); | |
1571 | fprintf (file, "\n\n"); | |
1572 | ||
1573 | i = 1; | |
1574 | fprintf (file, "Level %d (current level)\n", i); | |
1575 | for (j = (int) VEC_length (tree, block_defs_stack) - 1; j >= 0; j--) | |
1576 | { | |
1577 | tree name, var; | |
b8698a0f | 1578 | |
38635499 DN |
1579 | name = VEC_index (tree, block_defs_stack, j); |
1580 | if (name == NULL_TREE) | |
1581 | { | |
1582 | i++; | |
1583 | if (n > 0 && i > n) | |
1584 | break; | |
1585 | fprintf (file, "\nLevel %d\n", i); | |
1586 | continue; | |
1587 | } | |
1588 | ||
1589 | if (DECL_P (name)) | |
1590 | { | |
1591 | var = name; | |
1592 | name = NULL_TREE; | |
1593 | } | |
1594 | else | |
1595 | { | |
1596 | var = SSA_NAME_VAR (name); | |
1597 | if (!is_gimple_reg (var)) | |
1598 | { | |
1599 | j--; | |
1600 | var = VEC_index (tree, block_defs_stack, j); | |
1601 | } | |
1602 | } | |
1603 | ||
1604 | fprintf (file, " Previous CURRDEF ("); | |
1605 | print_generic_expr (file, var, 0); | |
1606 | fprintf (file, ") = "); | |
1607 | if (name) | |
1608 | print_generic_expr (file, name, 0); | |
1609 | else | |
1610 | fprintf (file, "<NIL>"); | |
1611 | fprintf (file, "\n"); | |
1612 | } | |
1613 | } | |
1614 | ||
1615 | ||
1616 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1617 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1618 | dumped. New levels are created when the dominator tree traversal | |
1619 | used for renaming enters a new sub-tree. */ | |
1620 | ||
24e47c76 | 1621 | DEBUG_FUNCTION void |
38635499 DN |
1622 | debug_defs_stack (int n) |
1623 | { | |
1624 | dump_defs_stack (stderr, n); | |
1625 | } | |
1626 | ||
1627 | ||
1628 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1629 | ||
1630 | void | |
1631 | dump_currdefs (FILE *file) | |
1632 | { | |
13714310 | 1633 | unsigned i; |
38635499 DN |
1634 | tree var; |
1635 | ||
13714310 RG |
1636 | if (VEC_empty (tree, symbols_to_rename)) |
1637 | return; | |
1638 | ||
38635499 | 1639 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
13714310 RG |
1640 | FOR_EACH_VEC_ELT (tree, symbols_to_rename, i, var) |
1641 | { | |
1642 | fprintf (file, "CURRDEF ("); | |
1643 | print_generic_expr (file, var, 0); | |
1644 | fprintf (file, ") = "); | |
1645 | if (get_current_def (var)) | |
1646 | print_generic_expr (file, get_current_def (var), 0); | |
1647 | else | |
1648 | fprintf (file, "<NIL>"); | |
1649 | fprintf (file, "\n"); | |
1650 | } | |
38635499 DN |
1651 | } |
1652 | ||
1653 | ||
1654 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1655 | ||
24e47c76 | 1656 | DEBUG_FUNCTION void |
38635499 DN |
1657 | debug_currdefs (void) |
1658 | { | |
1659 | dump_currdefs (stderr); | |
1660 | } | |
1661 | ||
1662 | ||
6de9cd9a DN |
1663 | /* Dump SSA information to FILE. */ |
1664 | ||
1665 | void | |
1666 | dump_tree_ssa (FILE *file) | |
1667 | { | |
6de9cd9a | 1668 | const char *funcname |
673fda6b | 1669 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
6de9cd9a | 1670 | |
38635499 | 1671 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
6de9cd9a | 1672 | |
b4e209fd | 1673 | dump_var_infos (file); |
38635499 DN |
1674 | dump_defs_stack (file, -1); |
1675 | dump_currdefs (file); | |
1676 | dump_tree_ssa_stats (file); | |
6de9cd9a DN |
1677 | } |
1678 | ||
1679 | ||
1680 | /* Dump SSA information to stderr. */ | |
1681 | ||
24e47c76 | 1682 | DEBUG_FUNCTION void |
6de9cd9a DN |
1683 | debug_tree_ssa (void) |
1684 | { | |
1685 | dump_tree_ssa (stderr); | |
1686 | } | |
1687 | ||
1688 | ||
7256233c DN |
1689 | /* Dump statistics for the hash table HTAB. */ |
1690 | ||
1691 | static void | |
1692 | htab_statistics (FILE *file, htab_t htab) | |
1693 | { | |
1694 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
1695 | (long) htab_size (htab), | |
1696 | (long) htab_elements (htab), | |
1697 | htab_collisions (htab)); | |
1698 | } | |
1699 | ||
1700 | ||
6de9cd9a DN |
1701 | /* Dump SSA statistics on FILE. */ |
1702 | ||
1703 | void | |
1704 | dump_tree_ssa_stats (FILE *file) | |
1705 | { | |
b4e209fd | 1706 | if (var_infos) |
38635499 | 1707 | { |
b4e209fd RG |
1708 | fprintf (file, "\nHash table statistics:\n"); |
1709 | fprintf (file, " var_infos: "); | |
1710 | htab_statistics (file, var_infos); | |
1711 | fprintf (file, "\n"); | |
38635499 | 1712 | } |
6de9cd9a DN |
1713 | } |
1714 | ||
1715 | ||
1716 | /* Dump SSA statistics on stderr. */ | |
1717 | ||
24e47c76 | 1718 | DEBUG_FUNCTION void |
6de9cd9a DN |
1719 | debug_tree_ssa_stats (void) |
1720 | { | |
1721 | dump_tree_ssa_stats (stderr); | |
1722 | } | |
1723 | ||
1724 | ||
b4e209fd | 1725 | /* Hashing and equality functions for VAR_INFOS. */ |
6de9cd9a | 1726 | |
7256233c | 1727 | static hashval_t |
b4e209fd | 1728 | var_info_hash (const void *p) |
6de9cd9a | 1729 | { |
b4e209fd | 1730 | return DECL_UID (((const struct var_info_d *)p)->var); |
7256233c DN |
1731 | } |
1732 | ||
1733 | static int | |
b4e209fd | 1734 | var_info_eq (const void *p1, const void *p2) |
6de9cd9a | 1735 | { |
b4e209fd RG |
1736 | return ((const struct var_info_d *)p1)->var |
1737 | == ((const struct var_info_d *)p2)->var; | |
7256233c | 1738 | } |
6de9cd9a | 1739 | |
6de9cd9a | 1740 | |
b4e209fd | 1741 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
6de9cd9a | 1742 | |
7256233c | 1743 | static int |
b4e209fd | 1744 | debug_var_infos_r (void **slot, void *data) |
7256233c | 1745 | { |
38635499 | 1746 | FILE *file = (FILE *) data; |
b4e209fd | 1747 | struct var_info_d *db_p = (struct var_info_d *) *slot; |
b8698a0f | 1748 | |
38635499 DN |
1749 | fprintf (file, "VAR: "); |
1750 | print_generic_expr (file, db_p->var, dump_flags); | |
b4e209fd RG |
1751 | bitmap_print (file, db_p->def_blocks.def_blocks, ", DEF_BLOCKS: { ", "}"); |
1752 | bitmap_print (file, db_p->def_blocks.livein_blocks, ", LIVEIN_BLOCKS: { ", "}"); | |
1753 | bitmap_print (file, db_p->def_blocks.phi_blocks, ", PHI_BLOCKS: { ", "}\n"); | |
6de9cd9a | 1754 | |
7256233c DN |
1755 | return 1; |
1756 | } | |
6de9cd9a | 1757 | |
6de9cd9a | 1758 | |
b4e209fd | 1759 | /* Dump the VAR_INFOS hash table on FILE. */ |
38635499 DN |
1760 | |
1761 | void | |
b4e209fd | 1762 | dump_var_infos (FILE *file) |
38635499 DN |
1763 | { |
1764 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
b4e209fd RG |
1765 | if (var_infos) |
1766 | htab_traverse (var_infos, debug_var_infos_r, file); | |
38635499 DN |
1767 | } |
1768 | ||
1769 | ||
b4e209fd | 1770 | /* Dump the VAR_INFOS hash table on stderr. */ |
6de9cd9a | 1771 | |
24e47c76 | 1772 | DEBUG_FUNCTION void |
b4e209fd | 1773 | debug_var_infos (void) |
7256233c | 1774 | { |
b4e209fd | 1775 | dump_var_infos (stderr); |
7256233c | 1776 | } |
6de9cd9a | 1777 | |
5f240ec4 | 1778 | |
0bca51f0 | 1779 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
6de9cd9a | 1780 | |
0bca51f0 DN |
1781 | static inline void |
1782 | register_new_update_single (tree new_name, tree old_name) | |
1783 | { | |
1784 | tree currdef = get_current_def (old_name); | |
5f240ec4 | 1785 | |
38635499 | 1786 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
0bca51f0 DN |
1787 | This stack is later used by the dominator tree callbacks to |
1788 | restore the reaching definitions for all the variables | |
1789 | defined in the block after a recursive visit to all its | |
1790 | immediately dominated blocks. */ | |
d4e6fecb NS |
1791 | VEC_reserve (tree, heap, block_defs_stack, 2); |
1792 | VEC_quick_push (tree, block_defs_stack, currdef); | |
1793 | VEC_quick_push (tree, block_defs_stack, old_name); | |
5f240ec4 | 1794 | |
0bca51f0 DN |
1795 | /* Set the current reaching definition for OLD_NAME to be |
1796 | NEW_NAME. */ | |
1797 | set_current_def (old_name, new_name); | |
1798 | } | |
7256233c | 1799 | |
6de9cd9a | 1800 | |
0bca51f0 DN |
1801 | /* Register NEW_NAME to be the new reaching definition for all the |
1802 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1803 | replace old SSA names with new ones. */ | |
7256233c | 1804 | |
0bca51f0 DN |
1805 | static inline void |
1806 | register_new_update_set (tree new_name, bitmap old_names) | |
1807 | { | |
1808 | bitmap_iterator bi; | |
1809 | unsigned i; | |
7256233c | 1810 | |
0bca51f0 DN |
1811 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1812 | register_new_update_single (new_name, ssa_name (i)); | |
6de9cd9a DN |
1813 | } |
1814 | ||
7256233c | 1815 | |
0bca51f0 | 1816 | |
84d65814 DN |
1817 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1818 | it is a symbol marked for renaming, replace it with USE_P's current | |
1819 | reaching definition. */ | |
1820 | ||
1821 | static inline void | |
1822 | maybe_replace_use (use_operand_p use_p) | |
1823 | { | |
1824 | tree rdef = NULL_TREE; | |
1825 | tree use = USE_FROM_PTR (use_p); | |
1826 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1827 | ||
13714310 | 1828 | if (marked_for_renaming (sym)) |
84d65814 DN |
1829 | rdef = get_reaching_def (sym); |
1830 | else if (is_old_name (use)) | |
1831 | rdef = get_reaching_def (use); | |
1832 | ||
1833 | if (rdef && rdef != use) | |
1834 | SET_USE (use_p, rdef); | |
1835 | } | |
1836 | ||
1837 | ||
b5b8b0ac AO |
1838 | /* Same as maybe_replace_use, but without introducing default stmts, |
1839 | returning false to indicate a need to do so. */ | |
1840 | ||
1841 | static inline bool | |
1842 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1843 | { | |
1844 | tree rdef = NULL_TREE; | |
1845 | tree use = USE_FROM_PTR (use_p); | |
1846 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1847 | ||
13714310 | 1848 | if (marked_for_renaming (sym)) |
b5b8b0ac AO |
1849 | rdef = get_current_def (sym); |
1850 | else if (is_old_name (use)) | |
1851 | { | |
1852 | rdef = get_current_def (use); | |
1853 | /* We can't assume that, if there's no current definition, the | |
1854 | default one should be used. It could be the case that we've | |
1855 | rearranged blocks so that the earlier definition no longer | |
1856 | dominates the use. */ | |
1857 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1858 | rdef = use; | |
1859 | } | |
1860 | else | |
1861 | rdef = use; | |
1862 | ||
1863 | if (rdef && rdef != use) | |
1864 | SET_USE (use_p, rdef); | |
1865 | ||
1866 | return rdef != NULL_TREE; | |
1867 | } | |
1868 | ||
1869 | ||
84d65814 DN |
1870 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1871 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1872 | register it as the current definition for the names replaced by | |
1873 | DEF_P. */ | |
1874 | ||
1875 | static inline void | |
3a56edc7 AO |
1876 | maybe_register_def (def_operand_p def_p, gimple stmt, |
1877 | gimple_stmt_iterator gsi) | |
84d65814 DN |
1878 | { |
1879 | tree def = DEF_FROM_PTR (def_p); | |
1880 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
1881 | ||
38635499 DN |
1882 | /* If DEF is a naked symbol that needs renaming, create a new |
1883 | name for it. */ | |
13714310 | 1884 | if (marked_for_renaming (sym)) |
84d65814 DN |
1885 | { |
1886 | if (DECL_P (def)) | |
1887 | { | |
3a56edc7 AO |
1888 | tree tracked_var; |
1889 | ||
84d65814 DN |
1890 | def = make_ssa_name (def, stmt); |
1891 | SET_DEF (def_p, def); | |
3a56edc7 AO |
1892 | |
1893 | tracked_var = target_for_debug_bind (sym); | |
1894 | if (tracked_var) | |
1895 | { | |
1896 | gimple note = gimple_build_debug_bind (tracked_var, def, stmt); | |
c47987fa JJ |
1897 | /* If stmt ends the bb, insert the debug stmt on the single |
1898 | non-EH edge from the stmt. */ | |
1899 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1900 | { | |
1901 | basic_block bb = gsi_bb (gsi); | |
1902 | edge_iterator ei; | |
1903 | edge e, ef = NULL; | |
1904 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1905 | if (!(e->flags & EDGE_EH)) | |
1906 | { | |
1907 | gcc_assert (!ef); | |
1908 | ef = e; | |
1909 | } | |
23d5ed5d AO |
1910 | /* If there are other predecessors to ef->dest, then |
1911 | there must be PHI nodes for the modified | |
1912 | variable, and therefore there will be debug bind | |
1913 | stmts after the PHI nodes. The debug bind notes | |
1914 | we'd insert would force the creation of a new | |
1915 | block (diverging codegen) and be redundant with | |
1916 | the post-PHI bind stmts, so don't add them. | |
1917 | ||
1918 | As for the exit edge, there wouldn't be redundant | |
1919 | bind stmts, but there wouldn't be a PC to bind | |
1920 | them to either, so avoid diverging the CFG. */ | |
1921 | if (ef && single_pred_p (ef->dest) | |
1922 | && ef->dest != EXIT_BLOCK_PTR) | |
1923 | { | |
1924 | /* If there were PHI nodes in the node, we'd | |
1925 | have to make sure the value we're binding | |
1926 | doesn't need rewriting. But there shouldn't | |
1927 | be PHI nodes in a single-predecessor block, | |
1928 | so we just add the note. */ | |
1929 | gsi_insert_on_edge_immediate (ef, note); | |
1930 | } | |
c47987fa JJ |
1931 | } |
1932 | else | |
1933 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
3a56edc7 | 1934 | } |
84d65814 DN |
1935 | } |
1936 | ||
1937 | register_new_update_single (def, sym); | |
1938 | } | |
1939 | else | |
1940 | { | |
1941 | /* If DEF is a new name, register it as a new definition | |
1942 | for all the names replaced by DEF. */ | |
1943 | if (is_new_name (def)) | |
1944 | register_new_update_set (def, names_replaced_by (def)); | |
1945 | ||
1946 | /* If DEF is an old name, register DEF as a new | |
1947 | definition for itself. */ | |
1948 | if (is_old_name (def)) | |
1949 | register_new_update_single (def, def); | |
1950 | } | |
1951 | } | |
1952 | ||
1953 | ||
0bca51f0 DN |
1954 | /* Update every variable used in the statement pointed-to by SI. The |
1955 | statement is assumed to be in SSA form already. Names in | |
1956 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1957 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1958 | will be registered as a new definition for their corresponding name | |
1959 | in OLD_SSA_NAMES. */ | |
1960 | ||
1961 | static void | |
3a56edc7 | 1962 | rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi) |
0bca51f0 | 1963 | { |
0bca51f0 DN |
1964 | use_operand_p use_p; |
1965 | def_operand_p def_p; | |
1966 | ssa_op_iter iter; | |
1967 | ||
0bca51f0 | 1968 | /* Only update marked statements. */ |
726a989a | 1969 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
0bca51f0 DN |
1970 | return; |
1971 | ||
1972 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1973 | { | |
1974 | fprintf (dump_file, "Updating SSA information for statement "); | |
726a989a | 1975 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
0bca51f0 DN |
1976 | } |
1977 | ||
1978 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
1979 | symbol is marked for renaming. */ | |
726a989a | 1980 | if (rewrite_uses_p (stmt)) |
b5b8b0ac AO |
1981 | { |
1982 | if (is_gimple_debug (stmt)) | |
1983 | { | |
1984 | bool failed = false; | |
1985 | ||
1986 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1987 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
1988 | { | |
1989 | failed = true; | |
1990 | break; | |
1991 | } | |
1992 | ||
1993 | if (failed) | |
1994 | { | |
1995 | /* DOM sometimes threads jumps in such a way that a | |
1996 | debug stmt ends up referencing a SSA variable that no | |
1997 | longer dominates the debug stmt, but such that all | |
1998 | incoming definitions refer to the same definition in | |
1999 | an earlier dominator. We could try to recover that | |
2000 | definition somehow, but this will have to do for now. | |
2001 | ||
2002 | Introducing a default definition, which is what | |
2003 | maybe_replace_use() would do in such cases, may | |
2004 | modify code generation, for the otherwise-unused | |
2005 | default definition would never go away, modifying SSA | |
2006 | version numbers all over. */ | |
2007 | gimple_debug_bind_reset_value (stmt); | |
2008 | update_stmt (stmt); | |
2009 | } | |
2010 | } | |
2011 | else | |
2012 | { | |
2013 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
2014 | maybe_replace_use (use_p); | |
2015 | } | |
2016 | } | |
0bca51f0 DN |
2017 | |
2018 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
2019 | Also register definitions for names whose underlying symbol is | |
2020 | marked for renaming. */ | |
726a989a | 2021 | if (register_defs_p (stmt)) |
5006671f | 2022 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
3a56edc7 | 2023 | maybe_register_def (def_p, stmt, gsi); |
0bca51f0 DN |
2024 | } |
2025 | ||
2026 | ||
2027 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
2028 | every PHI node found, check if any of its arguments is in | |
2029 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
2030 | definition, replace it. */ | |
2031 | ||
2032 | static void | |
ccf5c864 | 2033 | rewrite_update_phi_arguments (basic_block bb) |
0bca51f0 DN |
2034 | { |
2035 | edge e; | |
2036 | edge_iterator ei; | |
2ce79879 | 2037 | unsigned i; |
0bca51f0 DN |
2038 | |
2039 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2040 | { | |
726a989a RB |
2041 | gimple phi; |
2042 | gimple_vec phis; | |
0bca51f0 | 2043 | |
2ce79879 ZD |
2044 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
2045 | continue; | |
b8698a0f | 2046 | |
726a989a | 2047 | phis = VEC_index (gimple_vec, phis_to_rewrite, e->dest->index); |
ac47786e | 2048 | FOR_EACH_VEC_ELT (gimple, phis, i, phi) |
0bca51f0 | 2049 | { |
f5045c96 | 2050 | tree arg, lhs_sym, reaching_def = NULL; |
0bca51f0 DN |
2051 | use_operand_p arg_p; |
2052 | ||
726a989a | 2053 | gcc_assert (rewrite_uses_p (phi)); |
0bca51f0 DN |
2054 | |
2055 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2056 | arg = USE_FROM_PTR (arg_p); | |
2057 | ||
2058 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2059 | continue; | |
2060 | ||
726a989a | 2061 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
38635499 | 2062 | |
0bca51f0 DN |
2063 | if (arg == NULL_TREE) |
2064 | { | |
2065 | /* When updating a PHI node for a recently introduced | |
2066 | symbol we may find NULL arguments. That's why we | |
2067 | take the symbol from the LHS of the PHI node. */ | |
f5045c96 AM |
2068 | reaching_def = get_reaching_def (lhs_sym); |
2069 | ||
0bca51f0 DN |
2070 | } |
2071 | else | |
2072 | { | |
2073 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2074 | ||
13714310 | 2075 | if (marked_for_renaming (sym)) |
f5045c96 | 2076 | reaching_def = get_reaching_def (sym); |
0bca51f0 | 2077 | else if (is_old_name (arg)) |
f5045c96 AM |
2078 | reaching_def = get_reaching_def (arg); |
2079 | } | |
2080 | ||
2081 | /* Update the argument if there is a reaching def. */ | |
2082 | if (reaching_def) | |
2083 | { | |
2084 | gimple stmt; | |
2085 | source_location locus; | |
2086 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); | |
2087 | ||
2088 | SET_USE (arg_p, reaching_def); | |
2089 | stmt = SSA_NAME_DEF_STMT (reaching_def); | |
2090 | ||
b8698a0f | 2091 | /* Single element PHI nodes behave like copies, so get the |
f5045c96 | 2092 | location from the phi argument. */ |
b8698a0f | 2093 | if (gimple_code (stmt) == GIMPLE_PHI && |
f5045c96 AM |
2094 | gimple_phi_num_args (stmt) == 1) |
2095 | locus = gimple_phi_arg_location (stmt, 0); | |
2096 | else | |
2097 | locus = gimple_location (stmt); | |
2098 | ||
2099 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
0bca51f0 DN |
2100 | } |
2101 | ||
f5045c96 | 2102 | |
0bca51f0 DN |
2103 | if (e->flags & EDGE_ABNORMAL) |
2104 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2105 | } | |
2106 | } | |
2107 | } | |
2108 | ||
2109 | ||
ccf5c864 PB |
2110 | /* Initialization of block data structures for the incremental SSA |
2111 | update pass. Create a block local stack of reaching definitions | |
2112 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2113 | new definitions for every PHI node in the block. */ | |
2114 | ||
2115 | static void | |
2116 | rewrite_update_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2117 | basic_block bb) | |
2118 | { | |
ccf5c864 PB |
2119 | bool is_abnormal_phi; |
2120 | gimple_stmt_iterator gsi; | |
2121 | ||
2122 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
427f99e2 | 2123 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
ccf5c864 PB |
2124 | bb->index); |
2125 | ||
2126 | /* Mark the unwind point for this block. */ | |
2127 | VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE); | |
2128 | ||
2129 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
2130 | return; | |
2131 | ||
2132 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2133 | edge. */ | |
31ff2426 | 2134 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
ccf5c864 PB |
2135 | |
2136 | /* If any of the PHI nodes is a replacement for a name in | |
2137 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2138 | register it as a new definition for its corresponding name. Also | |
2139 | register definitions for names whose underlying symbols are | |
2140 | marked for renaming. */ | |
2141 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2142 | { | |
2143 | tree lhs, lhs_sym; | |
2144 | gimple phi = gsi_stmt (gsi); | |
2145 | ||
2146 | if (!register_defs_p (phi)) | |
2147 | continue; | |
b8698a0f | 2148 | |
ccf5c864 PB |
2149 | lhs = gimple_phi_result (phi); |
2150 | lhs_sym = SSA_NAME_VAR (lhs); | |
2151 | ||
13714310 | 2152 | if (marked_for_renaming (lhs_sym)) |
ccf5c864 PB |
2153 | register_new_update_single (lhs, lhs_sym); |
2154 | else | |
2155 | { | |
2156 | ||
2157 | /* If LHS is a new name, register a new definition for all | |
2158 | the names replaced by LHS. */ | |
2159 | if (is_new_name (lhs)) | |
2160 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
b8698a0f | 2161 | |
ccf5c864 PB |
2162 | /* If LHS is an OLD name, register it as a new definition |
2163 | for itself. */ | |
2164 | if (is_old_name (lhs)) | |
2165 | register_new_update_single (lhs, lhs); | |
2166 | } | |
2167 | ||
2168 | if (is_abnormal_phi) | |
2169 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2170 | } | |
2171 | ||
2172 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
2173 | if (TEST_BIT (interesting_blocks, bb->index)) | |
3a56edc7 AO |
2174 | { |
2175 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); | |
ccf5c864 | 2176 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
3a56edc7 AO |
2177 | rewrite_update_stmt (gsi_stmt (gsi), gsi); |
2178 | } | |
ccf5c864 PB |
2179 | |
2180 | /* Step 3. Update PHI nodes. */ | |
2181 | rewrite_update_phi_arguments (bb); | |
2182 | } | |
2183 | ||
2184 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2185 | the current reaching definition of every name re-written in BB to | |
2186 | the original reaching definition before visiting BB. This | |
2187 | unwinding must be done in the opposite order to what is done in | |
2188 | register_new_update_set. */ | |
2189 | ||
2190 | static void | |
2191 | rewrite_update_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, | |
2192 | basic_block bb ATTRIBUTE_UNUSED) | |
2193 | { | |
2194 | while (VEC_length (tree, block_defs_stack) > 0) | |
2195 | { | |
2196 | tree var = VEC_pop (tree, block_defs_stack); | |
2197 | tree saved_def; | |
b8698a0f | 2198 | |
ccf5c864 PB |
2199 | /* NULL indicates the unwind stop point for this block (see |
2200 | rewrite_update_enter_block). */ | |
2201 | if (var == NULL) | |
2202 | return; | |
2203 | ||
2204 | saved_def = VEC_pop (tree, block_defs_stack); | |
2205 | set_current_def (var, saved_def); | |
2206 | } | |
2207 | } | |
2208 | ||
2209 | ||
0bca51f0 | 2210 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
b8698a0f | 2211 | form. |
0bca51f0 DN |
2212 | |
2213 | ENTRY indicates the block where to start. Every block dominated by | |
2214 | ENTRY will be rewritten. | |
2215 | ||
2216 | WHAT indicates what actions will be taken by the renamer (see enum | |
2217 | rewrite_mode). | |
2218 | ||
2219 | BLOCKS are the set of interesting blocks for the dominator walker | |
2220 | to process. If this set is NULL, then all the nodes dominated | |
2221 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2222 | are not present in BLOCKS are ignored. */ | |
2223 | ||
2224 | static void | |
ccf5c864 | 2225 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
0bca51f0 DN |
2226 | { |
2227 | struct dom_walk_data walk_data; | |
b8698a0f | 2228 | |
0bca51f0 DN |
2229 | /* Rewrite all the basic blocks in the program. */ |
2230 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2231 | ||
2232 | /* Setup callbacks for the generic dominator tree walker. */ | |
2233 | memset (&walk_data, 0, sizeof (walk_data)); | |
2234 | ||
2235 | walk_data.dom_direction = CDI_DOMINATORS; | |
0bca51f0 DN |
2236 | |
2237 | if (what == REWRITE_ALL) | |
ccf5c864 PB |
2238 | { |
2239 | walk_data.before_dom_children = rewrite_enter_block; | |
2240 | walk_data.after_dom_children = rewrite_leave_block; | |
2241 | } | |
0bca51f0 | 2242 | else if (what == REWRITE_UPDATE) |
ccf5c864 PB |
2243 | { |
2244 | walk_data.before_dom_children = rewrite_update_enter_block; | |
2245 | walk_data.after_dom_children = rewrite_update_leave_block; | |
2246 | } | |
0bca51f0 DN |
2247 | else |
2248 | gcc_unreachable (); | |
2249 | ||
d4e6fecb | 2250 | block_defs_stack = VEC_alloc (tree, heap, 10); |
0bca51f0 DN |
2251 | |
2252 | /* Initialize the dominator walker. */ | |
2253 | init_walk_dominator_tree (&walk_data); | |
2254 | ||
2255 | /* Recursively walk the dominator tree rewriting each statement in | |
2256 | each basic block. */ | |
2257 | walk_dominator_tree (&walk_data, entry); | |
2258 | ||
2259 | /* Finalize the dominator walker. */ | |
2260 | fini_walk_dominator_tree (&walk_data); | |
2261 | ||
2262 | /* Debugging dumps. */ | |
2263 | if (dump_file && (dump_flags & TDF_STATS)) | |
2264 | { | |
2265 | dump_dfa_stats (dump_file); | |
b4e209fd | 2266 | if (var_infos) |
0bca51f0 DN |
2267 | dump_tree_ssa_stats (dump_file); |
2268 | } | |
b8698a0f | 2269 | |
d4e6fecb | 2270 | VEC_free (tree, heap, block_defs_stack); |
0bca51f0 DN |
2271 | |
2272 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2273 | } | |
2274 | ||
2275 | ||
ccf5c864 PB |
2276 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2277 | at the start of each block, and call mark_def_sites for each statement. */ | |
6de9cd9a | 2278 | |
5f240ec4 | 2279 | static void |
ccf5c864 | 2280 | mark_def_sites_block (struct dom_walk_data *walk_data, basic_block bb) |
5f240ec4 | 2281 | { |
38635499 | 2282 | struct mark_def_sites_global_data *gd; |
ccf5c864 PB |
2283 | bitmap kills; |
2284 | gimple_stmt_iterator gsi; | |
2285 | ||
38635499 | 2286 | gd = (struct mark_def_sites_global_data *) walk_data->global_data; |
ccf5c864 PB |
2287 | kills = gd->kills; |
2288 | ||
2289 | bitmap_clear (kills); | |
2290 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2291 | mark_def_sites (bb, gsi_stmt (gsi), kills); | |
7256233c | 2292 | } |
5f240ec4 | 2293 | |
5f240ec4 | 2294 | |
0bca51f0 DN |
2295 | /* Mark the definition site blocks for each variable, so that we know |
2296 | where the variable is actually live. | |
2297 | ||
ccf5c864 PB |
2298 | The INTERESTING_BLOCKS global will be filled in with all the blocks |
2299 | that should be processed by the renamer. It is assumed that the | |
2300 | caller has already initialized and zeroed it. */ | |
5f240ec4 | 2301 | |
0bca51f0 | 2302 | static void |
ccf5c864 | 2303 | mark_def_site_blocks (void) |
7256233c | 2304 | { |
7256233c DN |
2305 | struct dom_walk_data walk_data; |
2306 | struct mark_def_sites_global_data mark_def_sites_global_data; | |
5f240ec4 | 2307 | |
7256233c DN |
2308 | /* Setup callbacks for the generic dominator tree walker to find and |
2309 | mark definition sites. */ | |
7256233c DN |
2310 | walk_data.dom_direction = CDI_DOMINATORS; |
2311 | walk_data.initialize_block_local_data = NULL; | |
ccf5c864 PB |
2312 | walk_data.before_dom_children = mark_def_sites_block; |
2313 | walk_data.after_dom_children = NULL; | |
5f240ec4 | 2314 | |
7256233c DN |
2315 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2316 | large enough to accommodate all the variables referenced in the | |
2317 | function, not just the ones we are renaming. */ | |
2318 | mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); | |
2319 | walk_data.global_data = &mark_def_sites_global_data; | |
6de9cd9a | 2320 | |
7256233c DN |
2321 | /* We do not have any local data. */ |
2322 | walk_data.block_local_data_size = 0; | |
2323 | ||
2324 | /* Initialize the dominator walker. */ | |
2325 | init_walk_dominator_tree (&walk_data); | |
2326 | ||
2327 | /* Recursively walk the dominator tree. */ | |
2328 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
2329 | ||
2330 | /* Finalize the dominator walker. */ | |
2331 | fini_walk_dominator_tree (&walk_data); | |
2332 | ||
2333 | /* We no longer need this bitmap, clear and free it. */ | |
2334 | BITMAP_FREE (mark_def_sites_global_data.kills); | |
6de9cd9a DN |
2335 | } |
2336 | ||
6de9cd9a | 2337 | |
38635499 DN |
2338 | /* Initialize internal data needed during renaming. */ |
2339 | ||
2340 | static void | |
2341 | init_ssa_renamer (void) | |
2342 | { | |
38635499 DN |
2343 | cfun->gimple_df->in_ssa_p = false; |
2344 | ||
2345 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
b4e209fd RG |
2346 | gcc_assert (var_infos == NULL); |
2347 | var_infos = htab_create (VEC_length (tree, cfun->local_decls), | |
2348 | var_info_hash, var_info_eq, NULL); | |
38635499 | 2349 | |
b4e209fd | 2350 | bitmap_obstack_initialize (&update_ssa_obstack); |
38635499 DN |
2351 | } |
2352 | ||
2353 | ||
2354 | /* Deallocate internal data structures used by the renamer. */ | |
2355 | ||
2356 | static void | |
2357 | fini_ssa_renamer (void) | |
2358 | { | |
b4e209fd | 2359 | if (var_infos) |
38635499 | 2360 | { |
b4e209fd RG |
2361 | htab_delete (var_infos); |
2362 | var_infos = NULL; | |
38635499 DN |
2363 | } |
2364 | ||
b4e209fd RG |
2365 | bitmap_obstack_release (&update_ssa_obstack); |
2366 | ||
13714310 RG |
2367 | cfun->gimple_df->ssa_renaming_needed = 0; |
2368 | cfun->gimple_df->rename_vops = 0; | |
38635499 DN |
2369 | cfun->gimple_df->in_ssa_p = true; |
2370 | } | |
2371 | ||
7256233c | 2372 | /* Main entry point into the SSA builder. The renaming process |
0bca51f0 | 2373 | proceeds in four main phases: |
6de9cd9a | 2374 | |
0bca51f0 DN |
2375 | 1- Compute dominance frontier and immediate dominators, needed to |
2376 | insert PHI nodes and rename the function in dominator tree | |
2377 | order. | |
6de9cd9a | 2378 | |
0bca51f0 | 2379 | 2- Find and mark all the blocks that define variables |
7256233c | 2380 | (mark_def_site_blocks). |
6de9cd9a | 2381 | |
0bca51f0 | 2382 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
6de9cd9a | 2383 | |
0bca51f0 | 2384 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
6de9cd9a | 2385 | |
77bfa778 | 2386 | Steps 3 and 4 are done using the dominator tree walker |
0bca51f0 | 2387 | (walk_dominator_tree). */ |
7256233c | 2388 | |
c2924966 | 2389 | static unsigned int |
0bca51f0 | 2390 | rewrite_into_ssa (void) |
6de9cd9a | 2391 | { |
0fc555fb | 2392 | bitmap_head *dfs; |
7256233c | 2393 | basic_block bb; |
b8698a0f | 2394 | |
0bca51f0 | 2395 | /* Initialize operand data structures. */ |
3828719a | 2396 | init_ssa_operands (cfun); |
6de9cd9a | 2397 | |
38635499 DN |
2398 | /* Initialize internal data needed by the renamer. */ |
2399 | init_ssa_renamer (); | |
2400 | ||
0bca51f0 DN |
2401 | /* Initialize the set of interesting blocks. The callback |
2402 | mark_def_sites will add to this set those blocks that the renamer | |
2403 | should process. */ | |
2404 | interesting_blocks = sbitmap_alloc (last_basic_block); | |
2405 | sbitmap_zero (interesting_blocks); | |
6de9cd9a | 2406 | |
af5d3a18 | 2407 | /* Initialize dominance frontier. */ |
0fc555fb | 2408 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
7256233c | 2409 | FOR_EACH_BB (bb) |
0fc555fb | 2410 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
6de9cd9a | 2411 | |
0bca51f0 DN |
2412 | /* 1- Compute dominance frontiers. */ |
2413 | calculate_dominance_info (CDI_DOMINATORS); | |
7256233c | 2414 | compute_dominance_frontiers (dfs); |
6de9cd9a | 2415 | |
0bca51f0 | 2416 | /* 2- Find and mark definition sites. */ |
ccf5c864 | 2417 | mark_def_site_blocks (); |
0bca51f0 DN |
2418 | |
2419 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
84d65814 | 2420 | insert_phi_nodes (dfs); |
6de9cd9a | 2421 | |
0bca51f0 | 2422 | /* 4- Rename all the blocks. */ |
ccf5c864 | 2423 | rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL); |
6de9cd9a | 2424 | |
7256233c DN |
2425 | /* Free allocated memory. */ |
2426 | FOR_EACH_BB (bb) | |
0fc555fb | 2427 | bitmap_clear (&dfs[bb->index]); |
7256233c | 2428 | free (dfs); |
6de9cd9a | 2429 | |
b5dcb2b9 JL |
2430 | sbitmap_free (interesting_blocks); |
2431 | ||
38635499 DN |
2432 | fini_ssa_renamer (); |
2433 | ||
c2924966 | 2434 | return 0; |
6de9cd9a DN |
2435 | } |
2436 | ||
2437 | ||
b8698a0f | 2438 | struct gimple_opt_pass pass_build_ssa = |
6de9cd9a | 2439 | { |
8ddbbcae JH |
2440 | { |
2441 | GIMPLE_PASS, | |
7256233c DN |
2442 | "ssa", /* name */ |
2443 | NULL, /* gate */ | |
0bca51f0 | 2444 | rewrite_into_ssa, /* execute */ |
7256233c DN |
2445 | NULL, /* sub */ |
2446 | NULL, /* next */ | |
2447 | 0, /* static_pass_number */ | |
a222c01a | 2448 | TV_TREE_SSA_OTHER, /* tv_id */ |
46eb666a | 2449 | PROP_cfg, /* properties_required */ |
7256233c DN |
2450 | PROP_ssa, /* properties_provided */ |
2451 | 0, /* properties_destroyed */ | |
2452 | 0, /* todo_flags_start */ | |
39c58b3a | 2453 | TODO_verify_ssa |
8ddbbcae JH |
2454 | | TODO_remove_unused_locals /* todo_flags_finish */ |
2455 | } | |
7256233c | 2456 | }; |
6de9cd9a DN |
2457 | |
2458 | ||
0bca51f0 DN |
2459 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2460 | renamer. BLOCKS is the set of blocks that need updating. */ | |
6de9cd9a | 2461 | |
0bca51f0 | 2462 | static void |
726a989a | 2463 | mark_def_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
6de9cd9a | 2464 | { |
95dd3097 | 2465 | gcc_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
726a989a | 2466 | set_register_defs (stmt, true); |
0bca51f0 DN |
2467 | |
2468 | if (insert_phi_p) | |
2469 | { | |
726a989a | 2470 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
0bca51f0 | 2471 | |
0bca51f0 DN |
2472 | set_def_block (var, bb, is_phi_p); |
2473 | ||
2474 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2475 | site for both itself and all the old names replaced by it. */ | |
2476 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2477 | { | |
2478 | bitmap_iterator bi; | |
2479 | unsigned i; | |
2480 | bitmap set = names_replaced_by (var); | |
2481 | if (set) | |
2482 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2483 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2484 | } | |
2485 | } | |
2486 | } | |
2487 | ||
2488 | ||
2489 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2490 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
95dd3097 | 2491 | nodes. */ |
0bca51f0 DN |
2492 | |
2493 | static inline void | |
726a989a | 2494 | mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) |
0bca51f0 | 2495 | { |
726a989a | 2496 | basic_block def_bb = gimple_bb (stmt); |
2ce79879 | 2497 | |
95dd3097 ZD |
2498 | mark_block_for_update (def_bb); |
2499 | mark_block_for_update (bb); | |
2500 | ||
726a989a | 2501 | if (gimple_code (stmt) == GIMPLE_PHI) |
2ce79879 ZD |
2502 | mark_phi_for_rewrite (def_bb, stmt); |
2503 | else | |
b5b8b0ac AO |
2504 | { |
2505 | set_rewrite_uses (stmt, true); | |
2506 | ||
2507 | if (is_gimple_debug (stmt)) | |
2508 | return; | |
2509 | } | |
0bca51f0 DN |
2510 | |
2511 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2512 | to BB. Note that we cannot just use the block holding VAR's | |
2513 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2514 | it will have several definitions (itself and all the names that | |
2515 | replace it). */ | |
2516 | if (insert_phi_p) | |
2517 | { | |
84d65814 | 2518 | struct def_blocks_d *db_p = get_def_blocks_for (var); |
0bca51f0 DN |
2519 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2520 | set_livein_block (var, bb); | |
2521 | } | |
2522 | } | |
2523 | ||
2524 | ||
0bca51f0 | 2525 | /* Do a dominator walk starting at BB processing statements that |
13714310 | 2526 | reference symbols in SSA operands. This is very similar to |
84d65814 | 2527 | mark_def_sites, but the scan handles statements whose operands may |
95dd3097 | 2528 | already be SSA names. |
0bca51f0 | 2529 | |
84d65814 DN |
2530 | If INSERT_PHI_P is true, mark those uses as live in the |
2531 | corresponding block. This is later used by the PHI placement | |
38635499 DN |
2532 | algorithm to make PHI pruning decisions. |
2533 | ||
2534 | FIXME. Most of this would be unnecessary if we could associate a | |
2535 | symbol to all the SSA names that reference it. But that | |
2536 | sounds like it would be expensive to maintain. Still, it | |
2537 | would be interesting to see if it makes better sense to do | |
2538 | that. */ | |
0bca51f0 DN |
2539 | |
2540 | static void | |
95dd3097 | 2541 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
0bca51f0 DN |
2542 | { |
2543 | basic_block son; | |
726a989a | 2544 | gimple_stmt_iterator si; |
f074ff6c ZD |
2545 | edge e; |
2546 | edge_iterator ei; | |
0bca51f0 | 2547 | |
95dd3097 ZD |
2548 | mark_block_for_update (bb); |
2549 | ||
0bca51f0 | 2550 | /* Process PHI nodes marking interesting those that define or use |
84d65814 | 2551 | the symbols that we are interested in. */ |
726a989a | 2552 | for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2553 | { |
726a989a RB |
2554 | gimple phi = gsi_stmt (si); |
2555 | tree lhs_sym, lhs = gimple_phi_result (phi); | |
0bca51f0 | 2556 | |
0bca51f0 DN |
2557 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
2558 | ||
13714310 RG |
2559 | if (TREE_CODE (lhs) == SSA_NAME |
2560 | && (TREE_CODE (lhs_sym) != VAR_DECL | |
2561 | || !VAR_DECL_IS_VIRTUAL_OPERAND (lhs_sym) | |
2562 | || !cfun->gimple_df->rename_vops)) | |
f074ff6c | 2563 | continue; |
726a989a | 2564 | |
13714310 | 2565 | mark_for_renaming (lhs_sym); |
f074ff6c ZD |
2566 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2567 | ||
2568 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2569 | to process the arguments of the phi nodes of the successor edges of | |
2570 | BB at the end of prepare_block_for_update, however, that turns out | |
2571 | to be significantly more expensive. Doing it here is conservatively | |
2572 | correct -- it may only cause us to believe a value to be live in a | |
2573 | block that also contains its definition, and thus insert a few more | |
2574 | phi nodes for it. */ | |
2575 | FOR_EACH_EDGE (e, ei, bb->preds) | |
726a989a | 2576 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
0bca51f0 DN |
2577 | } |
2578 | ||
2579 | /* Process the statements. */ | |
726a989a | 2580 | for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
0bca51f0 | 2581 | { |
726a989a | 2582 | gimple stmt; |
0bca51f0 DN |
2583 | ssa_op_iter i; |
2584 | use_operand_p use_p; | |
2585 | def_operand_p def_p; | |
b8698a0f | 2586 | |
726a989a | 2587 | stmt = gsi_stmt (si); |
0bca51f0 | 2588 | |
13714310 RG |
2589 | if (cfun->gimple_df->rename_vops |
2590 | && gimple_vuse (stmt)) | |
0bca51f0 | 2591 | { |
13714310 | 2592 | tree use = gimple_vuse (stmt); |
0bca51f0 | 2593 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
13714310 RG |
2594 | mark_for_renaming (sym); |
2595 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2596 | } |
2597 | ||
13714310 | 2598 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
0bca51f0 | 2599 | { |
13714310 RG |
2600 | tree use = USE_FROM_PTR (use_p); |
2601 | if (!DECL_P (use)) | |
2602 | continue; | |
2603 | mark_for_renaming (use); | |
2604 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2605 | } | |
2606 | ||
2607 | if (cfun->gimple_df->rename_vops | |
2608 | && gimple_vdef (stmt)) | |
2609 | { | |
2610 | tree def = gimple_vdef (stmt); | |
0bca51f0 | 2611 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
13714310 RG |
2612 | mark_for_renaming (sym); |
2613 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2614 | } | |
2615 | ||
2616 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2617 | { | |
2618 | tree def = DEF_FROM_PTR (def_p); | |
2619 | if (!DECL_P (def)) | |
2620 | continue; | |
2621 | mark_for_renaming (def); | |
2622 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2623 | } |
2624 | } | |
2625 | ||
2626 | /* Now visit all the blocks dominated by BB. */ | |
84d65814 | 2627 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
38635499 DN |
2628 | son; |
2629 | son = next_dom_son (CDI_DOMINATORS, son)) | |
95dd3097 | 2630 | prepare_block_for_update (son, insert_phi_p); |
84d65814 DN |
2631 | } |
2632 | ||
2633 | ||
2634 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2635 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2636 | prepare_names_to_update. */ | |
2637 | ||
2638 | static void | |
95dd3097 | 2639 | prepare_use_sites_for (tree name, bool insert_phi_p) |
84d65814 DN |
2640 | { |
2641 | use_operand_p use_p; | |
2642 | imm_use_iterator iter; | |
2643 | ||
2644 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) | |
2645 | { | |
726a989a RB |
2646 | gimple stmt = USE_STMT (use_p); |
2647 | basic_block bb = gimple_bb (stmt); | |
84d65814 | 2648 | |
726a989a | 2649 | if (gimple_code (stmt) == GIMPLE_PHI) |
84d65814 | 2650 | { |
f074ff6c | 2651 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
726a989a | 2652 | edge e = gimple_phi_arg_edge (stmt, ix); |
f074ff6c | 2653 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
84d65814 DN |
2654 | } |
2655 | else | |
2656 | { | |
2657 | /* For regular statements, mark this as an interesting use | |
2658 | for NAME. */ | |
95dd3097 | 2659 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
84d65814 DN |
2660 | } |
2661 | } | |
0bca51f0 DN |
2662 | } |
2663 | ||
2664 | ||
84d65814 DN |
2665 | /* Helper for prepare_names_to_update. Mark the definition site for |
2666 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2667 | prepare_names_to_update. */ | |
0bca51f0 DN |
2668 | |
2669 | static void | |
95dd3097 | 2670 | prepare_def_site_for (tree name, bool insert_phi_p) |
0bca51f0 | 2671 | { |
726a989a | 2672 | gimple stmt; |
0bca51f0 DN |
2673 | basic_block bb; |
2674 | ||
0bca51f0 DN |
2675 | gcc_assert (names_to_release == NULL |
2676 | || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name))); | |
2677 | ||
2678 | stmt = SSA_NAME_DEF_STMT (name); | |
726a989a | 2679 | bb = gimple_bb (stmt); |
0bca51f0 DN |
2680 | if (bb) |
2681 | { | |
2682 | gcc_assert (bb->index < last_basic_block); | |
95dd3097 ZD |
2683 | mark_block_for_update (bb); |
2684 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
0bca51f0 DN |
2685 | } |
2686 | } | |
2687 | ||
2688 | ||
84d65814 | 2689 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
95dd3097 ZD |
2690 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2691 | PHI nodes for newly created names. */ | |
0bca51f0 DN |
2692 | |
2693 | static void | |
95dd3097 | 2694 | prepare_names_to_update (bool insert_phi_p) |
0bca51f0 | 2695 | { |
dfea6c85 | 2696 | unsigned i = 0; |
0bca51f0 | 2697 | bitmap_iterator bi; |
b6e7e9af | 2698 | sbitmap_iterator sbi; |
0bca51f0 DN |
2699 | |
2700 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2701 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2702 | defining basic block (which most likely doesn't exist). Notice | |
2703 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2704 | want to replace existing instances. */ | |
2705 | if (names_to_release) | |
2706 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2707 | RESET_BIT (new_ssa_names, i); | |
2708 | ||
84d65814 DN |
2709 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2710 | names may be considered to be live-in on blocks that contain | |
2711 | definitions for their replacements. */ | |
b6e7e9af | 2712 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
95dd3097 | 2713 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
84d65814 | 2714 | |
0bca51f0 DN |
2715 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2716 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
b6e7e9af | 2717 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
84d65814 DN |
2718 | { |
2719 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
95dd3097 ZD |
2720 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2721 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
b6e7e9af | 2722 | } |
0bca51f0 DN |
2723 | } |
2724 | ||
2725 | ||
2726 | /* Dump all the names replaced by NAME to FILE. */ | |
2727 | ||
2728 | void | |
2729 | dump_names_replaced_by (FILE *file, tree name) | |
2730 | { | |
2731 | unsigned i; | |
2732 | bitmap old_set; | |
2733 | bitmap_iterator bi; | |
2734 | ||
2735 | print_generic_expr (file, name, 0); | |
2736 | fprintf (file, " -> { "); | |
2737 | ||
2738 | old_set = names_replaced_by (name); | |
2739 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2740 | { | |
2741 | print_generic_expr (file, ssa_name (i), 0); | |
2742 | fprintf (file, " "); | |
2743 | } | |
2744 | ||
2745 | fprintf (file, "}\n"); | |
2746 | } | |
2747 | ||
2748 | ||
2749 | /* Dump all the names replaced by NAME to stderr. */ | |
2750 | ||
24e47c76 | 2751 | DEBUG_FUNCTION void |
0bca51f0 DN |
2752 | debug_names_replaced_by (tree name) |
2753 | { | |
2754 | dump_names_replaced_by (stderr, name); | |
2755 | } | |
2756 | ||
2757 | ||
84d65814 | 2758 | /* Dump SSA update information to FILE. */ |
0bca51f0 DN |
2759 | |
2760 | void | |
84d65814 | 2761 | dump_update_ssa (FILE *file) |
0bca51f0 | 2762 | { |
dfea6c85 | 2763 | unsigned i = 0; |
0bca51f0 DN |
2764 | bitmap_iterator bi; |
2765 | ||
5006671f | 2766 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
2767 | return; |
2768 | ||
2769 | if (new_ssa_names && sbitmap_first_set_bit (new_ssa_names) >= 0) | |
2770 | { | |
b6e7e9af KH |
2771 | sbitmap_iterator sbi; |
2772 | ||
0bca51f0 DN |
2773 | fprintf (file, "\nSSA replacement table\n"); |
2774 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2775 | "O_1, ..., O_j\n\n"); | |
2776 | ||
b6e7e9af KH |
2777 | EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi) |
2778 | dump_names_replaced_by (file, ssa_name (i)); | |
0bca51f0 DN |
2779 | } |
2780 | ||
13714310 | 2781 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
0bca51f0 | 2782 | { |
427f99e2 | 2783 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
13714310 | 2784 | dump_decl_set (file, symbols_to_rename_set); |
5006671f | 2785 | fprintf (file, "\n"); |
0bca51f0 DN |
2786 | } |
2787 | ||
0bca51f0 DN |
2788 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2789 | { | |
427f99e2 | 2790 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
0bca51f0 DN |
2791 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2792 | { | |
2793 | print_generic_expr (file, ssa_name (i), 0); | |
2794 | fprintf (file, " "); | |
2795 | } | |
427f99e2 | 2796 | fprintf (file, "\n"); |
0bca51f0 | 2797 | } |
0bca51f0 DN |
2798 | } |
2799 | ||
2800 | ||
84d65814 | 2801 | /* Dump SSA update information to stderr. */ |
0bca51f0 | 2802 | |
24e47c76 | 2803 | DEBUG_FUNCTION void |
84d65814 | 2804 | debug_update_ssa (void) |
0bca51f0 | 2805 | { |
84d65814 | 2806 | dump_update_ssa (stderr); |
0bca51f0 DN |
2807 | } |
2808 | ||
2809 | ||
2810 | /* Initialize data structures used for incremental SSA updates. */ | |
2811 | ||
2812 | static void | |
5006671f | 2813 | init_update_ssa (struct function *fn) |
0bca51f0 | 2814 | { |
84d65814 | 2815 | /* Reserve more space than the current number of names. The calls to |
0bca51f0 DN |
2816 | add_new_name_mapping are typically done after creating new SSA |
2817 | names, so we'll need to reallocate these arrays. */ | |
2818 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2819 | sbitmap_zero (old_ssa_names); | |
2820 | ||
2821 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
2822 | sbitmap_zero (new_ssa_names); | |
2823 | ||
891f2df6 RG |
2824 | bitmap_obstack_initialize (&update_ssa_obstack); |
2825 | ||
0bca51f0 | 2826 | names_to_release = NULL; |
5006671f | 2827 | update_ssa_initialized_fn = fn; |
0bca51f0 DN |
2828 | } |
2829 | ||
2830 | ||
2831 | /* Deallocate data structures used for incremental SSA updates. */ | |
2832 | ||
84d65814 | 2833 | void |
0bca51f0 DN |
2834 | delete_update_ssa (void) |
2835 | { | |
2836 | unsigned i; | |
2837 | bitmap_iterator bi; | |
2838 | ||
2839 | sbitmap_free (old_ssa_names); | |
2840 | old_ssa_names = NULL; | |
2841 | ||
2842 | sbitmap_free (new_ssa_names); | |
2843 | new_ssa_names = NULL; | |
2844 | ||
13714310 RG |
2845 | BITMAP_FREE (symbols_to_rename_set); |
2846 | symbols_to_rename_set = NULL; | |
2847 | VEC_free (tree, heap, symbols_to_rename); | |
0bca51f0 DN |
2848 | |
2849 | if (names_to_release) | |
2850 | { | |
2851 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2852 | release_ssa_name (ssa_name (i)); | |
2853 | BITMAP_FREE (names_to_release); | |
2854 | } | |
2855 | ||
95dd3097 | 2856 | clear_ssa_name_info (); |
38635499 DN |
2857 | |
2858 | fini_ssa_renamer (); | |
2859 | ||
2860 | if (blocks_with_phis_to_rewrite) | |
2861 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2862 | { | |
726a989a | 2863 | gimple_vec phis = VEC_index (gimple_vec, phis_to_rewrite, i); |
38635499 | 2864 | |
726a989a RB |
2865 | VEC_free (gimple, heap, phis); |
2866 | VEC_replace (gimple_vec, phis_to_rewrite, i, NULL); | |
38635499 DN |
2867 | } |
2868 | ||
2869 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2870 | BITMAP_FREE (blocks_to_update); | |
891f2df6 | 2871 | |
5006671f | 2872 | update_ssa_initialized_fn = NULL; |
0bca51f0 DN |
2873 | } |
2874 | ||
2875 | ||
2876 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
2877 | operand pointed to by DEF_P with the newly created name. Return | |
2878 | the new name and register the replacement mapping <NEW, OLD> in | |
2879 | update_ssa's tables. */ | |
2880 | ||
2881 | tree | |
726a989a | 2882 | create_new_def_for (tree old_name, gimple stmt, def_operand_p def) |
0bca51f0 DN |
2883 | { |
2884 | tree new_name = duplicate_ssa_name (old_name, stmt); | |
2885 | ||
2886 | SET_DEF (def, new_name); | |
2887 | ||
726a989a | 2888 | if (gimple_code (stmt) == GIMPLE_PHI) |
0bca51f0 | 2889 | { |
726a989a | 2890 | basic_block bb = gimple_bb (stmt); |
0bca51f0 DN |
2891 | |
2892 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
31ff2426 | 2893 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
0bca51f0 DN |
2894 | } |
2895 | ||
2896 | register_new_name_mapping (new_name, old_name); | |
2897 | ||
2898 | /* For the benefit of passes that will be updating the SSA form on | |
2899 | their own, set the current reaching definition of OLD_NAME to be | |
2900 | NEW_NAME. */ | |
2901 | set_current_def (old_name, new_name); | |
2902 | ||
2903 | return new_name; | |
2904 | } | |
2905 | ||
2906 | ||
2907 | /* Register name NEW to be a replacement for name OLD. This function | |
2908 | must be called for every replacement that should be performed by | |
2909 | update_ssa. */ | |
2910 | ||
2911 | void | |
5006671f | 2912 | register_new_name_mapping (tree new_tree, tree old) |
0bca51f0 | 2913 | { |
5006671f RG |
2914 | if (!update_ssa_initialized_fn) |
2915 | init_update_ssa (cfun); | |
2916 | ||
2917 | gcc_assert (update_ssa_initialized_fn == cfun); | |
0bca51f0 | 2918 | |
5006671f | 2919 | add_new_name_mapping (new_tree, old); |
0bca51f0 DN |
2920 | } |
2921 | ||
2922 | ||
525174a2 | 2923 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
0bca51f0 DN |
2924 | |
2925 | void | |
525174a2 | 2926 | mark_virtual_operands_for_renaming (struct function *fn) |
0bca51f0 | 2927 | { |
525174a2 RG |
2928 | fn->gimple_df->ssa_renaming_needed = 1; |
2929 | fn->gimple_df->rename_vops = 1; | |
0bca51f0 DN |
2930 | } |
2931 | ||
2932 | ||
5006671f RG |
2933 | /* Return true if there is any work to be done by update_ssa |
2934 | for function FN. */ | |
0bca51f0 DN |
2935 | |
2936 | bool | |
5006671f | 2937 | need_ssa_update_p (struct function *fn) |
0bca51f0 | 2938 | { |
5006671f RG |
2939 | gcc_assert (fn != NULL); |
2940 | return (update_ssa_initialized_fn == fn | |
13714310 | 2941 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
0bca51f0 DN |
2942 | } |
2943 | ||
0bca51f0 DN |
2944 | /* Return true if name N has been registered in the replacement table. */ |
2945 | ||
2946 | bool | |
726a989a | 2947 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
0bca51f0 | 2948 | { |
5006671f | 2949 | if (!update_ssa_initialized_fn) |
0bca51f0 DN |
2950 | return false; |
2951 | ||
5006671f RG |
2952 | gcc_assert (update_ssa_initialized_fn == cfun); |
2953 | ||
2954 | return is_new_name (n) || is_old_name (n); | |
0bca51f0 DN |
2955 | } |
2956 | ||
2957 | ||
0bca51f0 DN |
2958 | /* Mark NAME to be released after update_ssa has finished. */ |
2959 | ||
2960 | void | |
2961 | release_ssa_name_after_update_ssa (tree name) | |
2962 | { | |
5006671f | 2963 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
0bca51f0 DN |
2964 | |
2965 | if (names_to_release == NULL) | |
2966 | names_to_release = BITMAP_ALLOC (NULL); | |
2967 | ||
2968 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
2969 | } | |
2970 | ||
2971 | ||
2972 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
2973 | frontier information. BLOCKS is the set of blocks to be updated. | |
2974 | ||
2975 | This is slightly different than the regular PHI insertion | |
2976 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
2977 | real names (i.e., GIMPLE registers) are inserted: | |
b8698a0f | 2978 | |
0bca51f0 DN |
2979 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
2980 | nodes inside the region affected by the block that defines VAR | |
2981 | and the blocks that define all its replacements. All these | |
84d65814 | 2982 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
0bca51f0 DN |
2983 | |
2984 | First, we compute the entry point to the region (ENTRY). This is | |
2985 | given by the nearest common dominator to all the definition | |
2986 | blocks. When computing the iterated dominance frontier (IDF), any | |
2987 | block not strictly dominated by ENTRY is ignored. | |
2988 | ||
2989 | We then call the standard PHI insertion algorithm with the pruned | |
2990 | IDF. | |
2991 | ||
2992 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
2993 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
2994 | ||
2995 | static void | |
0fc555fb | 2996 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
0bca51f0 DN |
2997 | unsigned update_flags) |
2998 | { | |
2999 | basic_block entry; | |
3000 | struct def_blocks_d *db; | |
3001 | bitmap idf, pruned_idf; | |
3002 | bitmap_iterator bi; | |
3003 | unsigned i; | |
3004 | ||
0bca51f0 | 3005 | if (TREE_CODE (var) == SSA_NAME) |
77a74ed7 | 3006 | gcc_checking_assert (is_old_name (var)); |
0bca51f0 | 3007 | else |
13714310 | 3008 | gcc_checking_assert (marked_for_renaming (var)); |
0bca51f0 DN |
3009 | |
3010 | /* Get all the definition sites for VAR. */ | |
3011 | db = find_def_blocks_for (var); | |
3012 | ||
3013 | /* No need to do anything if there were no definitions to VAR. */ | |
3014 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3015 | return; | |
3016 | ||
3017 | /* Compute the initial iterated dominance frontier. */ | |
38635499 | 3018 | idf = compute_idf (db->def_blocks, dfs); |
0bca51f0 DN |
3019 | pruned_idf = BITMAP_ALLOC (NULL); |
3020 | ||
3021 | if (TREE_CODE (var) == SSA_NAME) | |
3022 | { | |
3023 | if (update_flags == TODO_update_ssa) | |
3024 | { | |
3025 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3026 | only interested in IDF blocks dominated by the nearest | |
3027 | common dominator of all the definition blocks. */ | |
3028 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3029 | db->def_blocks); | |
0bca51f0 DN |
3030 | if (entry != ENTRY_BLOCK_PTR) |
3031 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) | |
3032 | if (BASIC_BLOCK (i) != entry | |
3033 | && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) | |
3034 | bitmap_set_bit (pruned_idf, i); | |
3035 | } | |
3036 | else | |
3037 | { | |
3038 | /* Otherwise, do not prune the IDF for VAR. */ | |
3039 | gcc_assert (update_flags == TODO_update_ssa_full_phi); | |
3040 | bitmap_copy (pruned_idf, idf); | |
3041 | } | |
3042 | } | |
3043 | else | |
3044 | { | |
3045 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3046 | for the first time, so we need to compute the full IDF for | |
3047 | it. */ | |
3048 | bitmap_copy (pruned_idf, idf); | |
0bca51f0 DN |
3049 | } |
3050 | ||
3051 | if (!bitmap_empty_p (pruned_idf)) | |
3052 | { | |
3053 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3054 | are included in the region to be updated. The feeding blocks | |
3055 | are important to guarantee that the PHI arguments are renamed | |
3056 | properly. */ | |
38635499 DN |
3057 | |
3058 | /* FIXME, this is not needed if we are updating symbols. We are | |
3059 | already starting at the ENTRY block anyway. */ | |
0bca51f0 DN |
3060 | bitmap_ior_into (blocks, pruned_idf); |
3061 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3062 | { | |
3063 | edge e; | |
3064 | edge_iterator ei; | |
3065 | basic_block bb = BASIC_BLOCK (i); | |
3066 | ||
3067 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3068 | if (e->src->index >= 0) | |
3069 | bitmap_set_bit (blocks, e->src->index); | |
3070 | } | |
3071 | ||
3072 | insert_phi_nodes_for (var, pruned_idf, true); | |
3073 | } | |
3074 | ||
3075 | BITMAP_FREE (pruned_idf); | |
3076 | BITMAP_FREE (idf); | |
3077 | } | |
3078 | ||
3079 | ||
3080 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3081 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3082 | ||
3083 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3084 | NEW_SSA_NAMES are all re-written to be reached by the | |
3085 | appropriate definition from NEW_SSA_NAMES. | |
3086 | ||
3087 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3088 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3089 | ||
3090 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
3091 | calling register_new_name_mapping for every pair of names that the | |
3092 | caller wants to replace. | |
3093 | ||
3094 | The caller identifies the new names that have been inserted and the | |
3095 | names that need to be replaced by calling register_new_name_mapping | |
3096 | for every pair <NEW, OLD>. Note that the function assumes that the | |
3097 | new names have already been inserted in the IL. | |
3098 | ||
3099 | For instance, given the following code: | |
3100 | ||
3101 | 1 L0: | |
3102 | 2 x_1 = PHI (0, x_5) | |
3103 | 3 if (x_1 < 10) | |
3104 | 4 if (x_1 > 7) | |
3105 | 5 y_2 = 0 | |
3106 | 6 else | |
3107 | 7 y_3 = x_1 + x_7 | |
3108 | 8 endif | |
3109 | 9 x_5 = x_1 + 1 | |
3110 | 10 goto L0; | |
3111 | 11 endif | |
3112 | ||
3113 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3114 | ||
3115 | 1 L0: | |
3116 | 2 x_1 = PHI (0, x_5) | |
3117 | 3 if (x_1 < 10) | |
3118 | 4 x_10 = ... | |
3119 | 5 if (x_1 > 7) | |
3120 | 6 y_2 = 0 | |
3121 | 7 else | |
3122 | 8 x_11 = ... | |
3123 | 9 y_3 = x_1 + x_7 | |
3124 | 10 endif | |
3125 | 11 x_5 = x_1 + 1 | |
3126 | 12 goto L0; | |
3127 | 13 endif | |
3128 | ||
3129 | We want to replace all the uses of x_1 with the new definitions of | |
3130 | x_10 and x_11. Note that the only uses that should be replaced are | |
3131 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3132 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3133 | renaming). | |
3134 | ||
3135 | Additionally, we may need to insert a PHI node at line 11 because | |
3136 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3137 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3138 | nodes is optional. They are not strictly necessary to preserve the | |
3139 | SSA form, and depending on what the caller inserted, they may not | |
3140 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3141 | aspects of how update_ssa operates, see the documentation for | |
3142 | TODO_update_ssa*. */ | |
3143 | ||
3144 | void | |
3145 | update_ssa (unsigned update_flags) | |
3146 | { | |
0bca51f0 DN |
3147 | basic_block bb, start_bb; |
3148 | bitmap_iterator bi; | |
dfea6c85 | 3149 | unsigned i = 0; |
0bca51f0 | 3150 | bool insert_phi_p; |
b6e7e9af | 3151 | sbitmap_iterator sbi; |
13714310 | 3152 | tree sym; |
0bca51f0 | 3153 | |
5006671f | 3154 | if (!need_ssa_update_p (cfun)) |
0bca51f0 DN |
3155 | return; |
3156 | ||
3157 | timevar_push (TV_TREE_SSA_INCREMENTAL); | |
3158 | ||
427f99e2 MJ |
3159 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3160 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3161 | ||
5006671f RG |
3162 | if (!update_ssa_initialized_fn) |
3163 | init_update_ssa (cfun); | |
3164 | gcc_assert (update_ssa_initialized_fn == cfun); | |
3165 | ||
2ce79879 ZD |
3166 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
3167 | if (!phis_to_rewrite) | |
726a989a | 3168 | phis_to_rewrite = VEC_alloc (gimple_vec, heap, last_basic_block); |
95dd3097 | 3169 | blocks_to_update = BITMAP_ALLOC (NULL); |
2ce79879 | 3170 | |
0bca51f0 DN |
3171 | /* Ensure that the dominance information is up-to-date. */ |
3172 | calculate_dominance_info (CDI_DOMINATORS); | |
3173 | ||
3174 | /* Only one update flag should be set. */ | |
3175 | gcc_assert (update_flags == TODO_update_ssa | |
3176 | || update_flags == TODO_update_ssa_no_phi | |
3177 | || update_flags == TODO_update_ssa_full_phi | |
3178 | || update_flags == TODO_update_ssa_only_virtuals); | |
3179 | ||
3180 | /* If we only need to update virtuals, remove all the mappings for | |
84d65814 DN |
3181 | real names before proceeding. The caller is responsible for |
3182 | having dealt with the name mappings before calling update_ssa. */ | |
0bca51f0 DN |
3183 | if (update_flags == TODO_update_ssa_only_virtuals) |
3184 | { | |
3185 | sbitmap_zero (old_ssa_names); | |
3186 | sbitmap_zero (new_ssa_names); | |
0bca51f0 DN |
3187 | } |
3188 | ||
84d65814 | 3189 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
0bca51f0 | 3190 | |
84d65814 DN |
3191 | /* If there are names defined in the replacement table, prepare |
3192 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3193 | OLD_SSA_NAMES. */ | |
3194 | if (sbitmap_first_set_bit (new_ssa_names) >= 0) | |
3195 | { | |
95dd3097 | 3196 | prepare_names_to_update (insert_phi_p); |
84d65814 DN |
3197 | |
3198 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3199 | removal, and there are no symbols to rename, then there's | |
3200 | nothing else to do. */ | |
3201 | if (sbitmap_first_set_bit (new_ssa_names) < 0 | |
13714310 | 3202 | && !cfun->gimple_df->ssa_renaming_needed) |
84d65814 DN |
3203 | goto done; |
3204 | } | |
3205 | ||
3206 | /* Next, determine the block at which to start the renaming process. */ | |
13714310 | 3207 | if (cfun->gimple_df->ssa_renaming_needed) |
84d65814 | 3208 | { |
b4e209fd RG |
3209 | /* If we rename bare symbols initialize the mapping to |
3210 | auxiliar info we need to keep track of. */ | |
3211 | var_infos = htab_create (47, var_info_hash, var_info_eq, NULL); | |
3212 | ||
84d65814 DN |
3213 | /* If we have to rename some symbols from scratch, we need to |
3214 | start the process at the root of the CFG. FIXME, it should | |
3215 | be possible to determine the nearest block that had a | |
3216 | definition for each of the symbols that are marked for | |
3217 | updating. For now this seems more work than it's worth. */ | |
3218 | start_bb = ENTRY_BLOCK_PTR; | |
3219 | ||
38635499 | 3220 | /* Traverse the CFG looking for existing definitions and uses of |
13714310 | 3221 | symbols in SSA operands. Mark interesting blocks and |
38635499 DN |
3222 | statements and set local live-in information for the PHI |
3223 | placement heuristics. */ | |
95dd3097 | 3224 | prepare_block_for_update (start_bb, insert_phi_p); |
0bca51f0 DN |
3225 | } |
3226 | else | |
84d65814 DN |
3227 | { |
3228 | /* Otherwise, the entry block to the region is the nearest | |
3229 | common dominator for the blocks in BLOCKS. */ | |
95dd3097 ZD |
3230 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3231 | blocks_to_update); | |
84d65814 | 3232 | } |
0bca51f0 DN |
3233 | |
3234 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
84d65814 | 3235 | of every block, creating new definitions for names in OLD_SSA_NAMES |
13714310 | 3236 | and for symbols found. */ |
0bca51f0 DN |
3237 | if (insert_phi_p) |
3238 | { | |
0fc555fb | 3239 | bitmap_head *dfs; |
9caf90a8 KH |
3240 | |
3241 | /* If the caller requested PHI nodes to be added, compute | |
3242 | dominance frontiers. */ | |
0fc555fb | 3243 | dfs = XNEWVEC (bitmap_head, last_basic_block); |
9caf90a8 | 3244 | FOR_EACH_BB (bb) |
0fc555fb | 3245 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
9caf90a8 KH |
3246 | compute_dominance_frontiers (dfs); |
3247 | ||
0bca51f0 DN |
3248 | if (sbitmap_first_set_bit (old_ssa_names) >= 0) |
3249 | { | |
b6e7e9af KH |
3250 | sbitmap_iterator sbi; |
3251 | ||
84d65814 DN |
3252 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3253 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3254 | will grow while we are traversing it (but it will not | |
3255 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3256 | for traversal. */ | |
0bca51f0 DN |
3257 | sbitmap tmp = sbitmap_alloc (old_ssa_names->n_bits); |
3258 | sbitmap_copy (tmp, old_ssa_names); | |
b6e7e9af | 3259 | EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i, sbi) |
95dd3097 | 3260 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
b6e7e9af | 3261 | update_flags); |
0bca51f0 DN |
3262 | sbitmap_free (tmp); |
3263 | } | |
3264 | ||
13714310 RG |
3265 | FOR_EACH_VEC_ELT (tree, symbols_to_rename, i, sym) |
3266 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, | |
38635499 | 3267 | update_flags); |
0bca51f0 | 3268 | |
9caf90a8 | 3269 | FOR_EACH_BB (bb) |
0fc555fb | 3270 | bitmap_clear (&dfs[bb->index]); |
9caf90a8 KH |
3271 | free (dfs); |
3272 | ||
0bca51f0 DN |
3273 | /* Insertion of PHI nodes may have added blocks to the region. |
3274 | We need to re-compute START_BB to include the newly added | |
3275 | blocks. */ | |
3276 | if (start_bb != ENTRY_BLOCK_PTR) | |
95dd3097 ZD |
3277 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3278 | blocks_to_update); | |
0bca51f0 DN |
3279 | } |
3280 | ||
3281 | /* Reset the current definition for name and symbol before renaming | |
3282 | the sub-graph. */ | |
b6e7e9af KH |
3283 | EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) |
3284 | set_current_def (ssa_name (i), NULL_TREE); | |
0bca51f0 | 3285 | |
13714310 RG |
3286 | FOR_EACH_VEC_ELT (tree, symbols_to_rename, i, sym) |
3287 | set_current_def (sym, NULL_TREE); | |
0bca51f0 DN |
3288 | |
3289 | /* Now start the renaming process at START_BB. */ | |
ccf5c864 PB |
3290 | interesting_blocks = sbitmap_alloc (last_basic_block); |
3291 | sbitmap_zero (interesting_blocks); | |
95dd3097 | 3292 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
ccf5c864 | 3293 | SET_BIT (interesting_blocks, i); |
0bca51f0 | 3294 | |
ccf5c864 | 3295 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
0bca51f0 | 3296 | |
ccf5c864 | 3297 | sbitmap_free (interesting_blocks); |
0bca51f0 DN |
3298 | |
3299 | /* Debugging dumps. */ | |
3300 | if (dump_file) | |
3301 | { | |
3302 | int c; | |
3303 | unsigned i; | |
3304 | ||
84d65814 | 3305 | dump_update_ssa (dump_file); |
0bca51f0 | 3306 | |
427f99e2 | 3307 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
0bca51f0 DN |
3308 | start_bb->index); |
3309 | ||
3310 | c = 0; | |
95dd3097 | 3311 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0bca51f0 DN |
3312 | c++; |
3313 | fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block); | |
427f99e2 | 3314 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
0bca51f0 DN |
3315 | c, PERCENT (c, last_basic_block)); |
3316 | ||
3317 | if (dump_flags & TDF_DETAILS) | |
3318 | { | |
0eb09f31 | 3319 | fprintf (dump_file, "Affected blocks:"); |
95dd3097 | 3320 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
0eb09f31 | 3321 | fprintf (dump_file, " %u", i); |
0bca51f0 DN |
3322 | fprintf (dump_file, "\n"); |
3323 | } | |
3324 | ||
3325 | fprintf (dump_file, "\n\n"); | |
3326 | } | |
3327 | ||
3328 | /* Free allocated memory. */ | |
84d65814 | 3329 | done: |
0bca51f0 DN |
3330 | delete_update_ssa (); |
3331 | ||
3332 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3333 | } |