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4ee9c684 | 1 | /* SSA Dominator optimizations for trees |
62b180e1 | 2 | Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006 |
3 | Free Software Foundation, Inc. | |
4ee9c684 | 4 | Contributed by Diego Novillo <dnovillo@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2, or (at your option) | |
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 | |
19 | along with GCC; see the file COPYING. If not, write to | |
67ce556b | 20 | the Free Software Foundation, 51 Franklin Street, Fifth Floor, |
21 | Boston, MA 02110-1301, USA. */ | |
4ee9c684 | 22 | |
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
26 | #include "tm.h" | |
27 | #include "tree.h" | |
28 | #include "flags.h" | |
29 | #include "rtl.h" | |
30 | #include "tm_p.h" | |
31 | #include "ggc.h" | |
32 | #include "basic-block.h" | |
388d1fc1 | 33 | #include "cfgloop.h" |
4ee9c684 | 34 | #include "output.h" |
4ee9c684 | 35 | #include "expr.h" |
36 | #include "function.h" | |
37 | #include "diagnostic.h" | |
38 | #include "timevar.h" | |
39 | #include "tree-dump.h" | |
40 | #include "tree-flow.h" | |
41 | #include "domwalk.h" | |
42 | #include "real.h" | |
43 | #include "tree-pass.h" | |
7d564439 | 44 | #include "tree-ssa-propagate.h" |
4ee9c684 | 45 | #include "langhooks.h" |
cf024d22 | 46 | #include "params.h" |
4ee9c684 | 47 | |
48 | /* This file implements optimizations on the dominator tree. */ | |
49 | ||
2f0993e7 | 50 | |
51 | /* Structure for recording edge equivalences as well as any pending | |
52 | edge redirections during the dominator optimizer. | |
53 | ||
54 | Computing and storing the edge equivalences instead of creating | |
55 | them on-demand can save significant amounts of time, particularly | |
56 | for pathological cases involving switch statements. | |
57 | ||
58 | These structures live for a single iteration of the dominator | |
59 | optimizer in the edge's AUX field. At the end of an iteration we | |
60 | free each of these structures and update the AUX field to point | |
61 | to any requested redirection target (the code for updating the | |
62 | CFG and SSA graph for edge redirection expects redirection edge | |
63 | targets to be in the AUX field for each edge. */ | |
64 | ||
65 | struct edge_info | |
66 | { | |
67 | /* If this edge creates a simple equivalence, the LHS and RHS of | |
68 | the equivalence will be stored here. */ | |
69 | tree lhs; | |
70 | tree rhs; | |
71 | ||
72 | /* Traversing an edge may also indicate one or more particular conditions | |
73 | are true or false. The number of recorded conditions can vary, but | |
74 | can be determined by the condition's code. So we have an array | |
75 | and its maximum index rather than use a varray. */ | |
76 | tree *cond_equivalences; | |
77 | unsigned int max_cond_equivalences; | |
2f0993e7 | 78 | }; |
79 | ||
80 | ||
4ee9c684 | 81 | /* Hash table with expressions made available during the renaming process. |
82 | When an assignment of the form X_i = EXPR is found, the statement is | |
83 | stored in this table. If the same expression EXPR is later found on the | |
84 | RHS of another statement, it is replaced with X_i (thus performing | |
85 | global redundancy elimination). Similarly as we pass through conditionals | |
86 | we record the conditional itself as having either a true or false value | |
87 | in this table. */ | |
88 | static htab_t avail_exprs; | |
89 | ||
9c629f0e | 90 | /* Stack of available expressions in AVAIL_EXPRs. Each block pushes any |
91 | expressions it enters into the hash table along with a marker entry | |
73645111 | 92 | (null). When we finish processing the block, we pop off entries and |
9c629f0e | 93 | remove the expressions from the global hash table until we hit the |
94 | marker. */ | |
046bfc77 | 95 | static VEC(tree,heap) *avail_exprs_stack; |
9c629f0e | 96 | |
a721131d | 97 | /* Stack of statements we need to rescan during finalization for newly |
98 | exposed variables. | |
99 | ||
100 | Statement rescanning must occur after the current block's available | |
101 | expressions are removed from AVAIL_EXPRS. Else we may change the | |
102 | hash code for an expression and be unable to find/remove it from | |
103 | AVAIL_EXPRS. */ | |
046bfc77 | 104 | static VEC(tree,heap) *stmts_to_rescan; |
a721131d | 105 | |
4ee9c684 | 106 | /* Structure for entries in the expression hash table. |
107 | ||
108 | This requires more memory for the hash table entries, but allows us | |
109 | to avoid creating silly tree nodes and annotations for conditionals, | |
110 | eliminates 2 global hash tables and two block local varrays. | |
111 | ||
112 | It also allows us to reduce the number of hash table lookups we | |
113 | have to perform in lookup_avail_expr and finally it allows us to | |
114 | significantly reduce the number of calls into the hashing routine | |
115 | itself. */ | |
a8046f60 | 116 | |
4ee9c684 | 117 | struct expr_hash_elt |
118 | { | |
119 | /* The value (lhs) of this expression. */ | |
120 | tree lhs; | |
121 | ||
122 | /* The expression (rhs) we want to record. */ | |
123 | tree rhs; | |
124 | ||
b66731e8 | 125 | /* The stmt pointer if this element corresponds to a statement. */ |
126 | tree stmt; | |
4ee9c684 | 127 | |
128 | /* The hash value for RHS/ann. */ | |
129 | hashval_t hash; | |
130 | }; | |
131 | ||
da43203c | 132 | /* Stack of dest,src pairs that need to be restored during finalization. |
133 | ||
134 | A NULL entry is used to mark the end of pairs which need to be | |
135 | restored during finalization of this block. */ | |
046bfc77 | 136 | static VEC(tree,heap) *const_and_copies_stack; |
da43203c | 137 | |
4ee9c684 | 138 | /* Track whether or not we have changed the control flow graph. */ |
139 | static bool cfg_altered; | |
140 | ||
35c15734 | 141 | /* Bitmap of blocks that have had EH statements cleaned. We should |
0870fd6e | 142 | remove their dead edges eventually. */ |
35c15734 | 143 | static bitmap need_eh_cleanup; |
144 | ||
4ee9c684 | 145 | /* Statistics for dominator optimizations. */ |
146 | struct opt_stats_d | |
147 | { | |
148 | long num_stmts; | |
149 | long num_exprs_considered; | |
150 | long num_re; | |
88dbf20f | 151 | long num_const_prop; |
152 | long num_copy_prop; | |
4ee9c684 | 153 | }; |
154 | ||
d0d897b6 | 155 | static struct opt_stats_d opt_stats; |
156 | ||
4ee9c684 | 157 | struct eq_expr_value |
158 | { | |
159 | tree src; | |
160 | tree dst; | |
161 | }; | |
162 | ||
163 | /* Local functions. */ | |
164 | static void optimize_stmt (struct dom_walk_data *, | |
165 | basic_block bb, | |
166 | block_stmt_iterator); | |
9c629f0e | 167 | static tree lookup_avail_expr (tree, bool); |
4ee9c684 | 168 | static hashval_t avail_expr_hash (const void *); |
23ace16d | 169 | static hashval_t real_avail_expr_hash (const void *); |
4ee9c684 | 170 | static int avail_expr_eq (const void *, const void *); |
171 | static void htab_statistics (FILE *, htab_t); | |
9c629f0e | 172 | static void record_cond (tree, tree); |
da43203c | 173 | static void record_const_or_copy (tree, tree); |
174 | static void record_equality (tree, tree); | |
2f0993e7 | 175 | static void record_equivalences_from_phis (basic_block); |
176 | static void record_equivalences_from_incoming_edge (basic_block); | |
8f628ee8 | 177 | static bool eliminate_redundant_computations (tree); |
180d0339 | 178 | static void record_equivalences_from_stmt (tree, int, stmt_ann_t); |
62b180e1 | 179 | static void dom_thread_across_edge (struct dom_walk_data *, edge); |
4ee9c684 | 180 | static void dom_opt_finalize_block (struct dom_walk_data *, basic_block); |
4ee9c684 | 181 | static void dom_opt_initialize_block (struct dom_walk_data *, basic_block); |
2f0993e7 | 182 | static void propagate_to_outgoing_edges (struct dom_walk_data *, basic_block); |
9c629f0e | 183 | static void remove_local_expressions_from_table (void); |
da43203c | 184 | static void restore_vars_to_original_value (void); |
c0735efa | 185 | static edge single_incoming_edge_ignoring_loop_edges (basic_block); |
4ee9c684 | 186 | |
88dbf20f | 187 | |
2f0993e7 | 188 | /* Allocate an EDGE_INFO for edge E and attach it to E. |
189 | Return the new EDGE_INFO structure. */ | |
190 | ||
191 | static struct edge_info * | |
192 | allocate_edge_info (edge e) | |
193 | { | |
194 | struct edge_info *edge_info; | |
195 | ||
945865c5 | 196 | edge_info = XCNEW (struct edge_info); |
2f0993e7 | 197 | |
198 | e->aux = edge_info; | |
199 | return edge_info; | |
200 | } | |
201 | ||
202 | /* Free all EDGE_INFO structures associated with edges in the CFG. | |
640e9781 | 203 | If a particular edge can be threaded, copy the redirection |
2f0993e7 | 204 | target from the EDGE_INFO structure into the edge's AUX field |
205 | as required by code to update the CFG and SSA graph for | |
206 | jump threading. */ | |
207 | ||
208 | static void | |
209 | free_all_edge_infos (void) | |
210 | { | |
211 | basic_block bb; | |
212 | edge_iterator ei; | |
213 | edge e; | |
214 | ||
215 | FOR_EACH_BB (bb) | |
216 | { | |
217 | FOR_EACH_EDGE (e, ei, bb->preds) | |
218 | { | |
945865c5 | 219 | struct edge_info *edge_info = (struct edge_info *) e->aux; |
2f0993e7 | 220 | |
221 | if (edge_info) | |
222 | { | |
2f0993e7 | 223 | if (edge_info->cond_equivalences) |
224 | free (edge_info->cond_equivalences); | |
225 | free (edge_info); | |
3cebc9d2 | 226 | e->aux = NULL; |
2f0993e7 | 227 | } |
228 | } | |
229 | } | |
230 | } | |
231 | ||
4ee9c684 | 232 | /* Jump threading, redundancy elimination and const/copy propagation. |
233 | ||
4ee9c684 | 234 | This pass may expose new symbols that need to be renamed into SSA. For |
235 | every new symbol exposed, its corresponding bit will be set in | |
591c2a30 | 236 | VARS_TO_RENAME. */ |
4ee9c684 | 237 | |
2a1990e9 | 238 | static unsigned int |
4ee9c684 | 239 | tree_ssa_dominator_optimize (void) |
240 | { | |
4ee9c684 | 241 | struct dom_walk_data walk_data; |
242 | unsigned int i; | |
388d1fc1 | 243 | struct loops loops_info; |
4ee9c684 | 244 | |
03ec6c0e | 245 | memset (&opt_stats, 0, sizeof (opt_stats)); |
246 | ||
4ee9c684 | 247 | /* Create our hash tables. */ |
23ace16d | 248 | avail_exprs = htab_create (1024, real_avail_expr_hash, avail_expr_eq, free); |
046bfc77 | 249 | avail_exprs_stack = VEC_alloc (tree, heap, 20); |
046bfc77 | 250 | const_and_copies_stack = VEC_alloc (tree, heap, 20); |
046bfc77 | 251 | stmts_to_rescan = VEC_alloc (tree, heap, 20); |
27335ffd | 252 | need_eh_cleanup = BITMAP_ALLOC (NULL); |
4ee9c684 | 253 | |
254 | /* Setup callbacks for the generic dominator tree walker. */ | |
255 | walk_data.walk_stmts_backward = false; | |
256 | walk_data.dom_direction = CDI_DOMINATORS; | |
180d0339 | 257 | walk_data.initialize_block_local_data = NULL; |
4ee9c684 | 258 | walk_data.before_dom_children_before_stmts = dom_opt_initialize_block; |
259 | walk_data.before_dom_children_walk_stmts = optimize_stmt; | |
2f0993e7 | 260 | walk_data.before_dom_children_after_stmts = propagate_to_outgoing_edges; |
4ee9c684 | 261 | walk_data.after_dom_children_before_stmts = NULL; |
262 | walk_data.after_dom_children_walk_stmts = NULL; | |
263 | walk_data.after_dom_children_after_stmts = dom_opt_finalize_block; | |
264 | /* Right now we only attach a dummy COND_EXPR to the global data pointer. | |
265 | When we attach more stuff we'll need to fill this out with a real | |
266 | structure. */ | |
267 | walk_data.global_data = NULL; | |
180d0339 | 268 | walk_data.block_local_data_size = 0; |
88dbf20f | 269 | walk_data.interesting_blocks = NULL; |
4ee9c684 | 270 | |
271 | /* Now initialize the dominator walker. */ | |
272 | init_walk_dominator_tree (&walk_data); | |
273 | ||
4ee9c684 | 274 | calculate_dominance_info (CDI_DOMINATORS); |
275 | ||
388d1fc1 | 276 | /* We need to know which edges exit loops so that we can |
277 | aggressively thread through loop headers to an exit | |
278 | edge. */ | |
279 | flow_loops_find (&loops_info); | |
280 | mark_loop_exit_edges (&loops_info); | |
281 | flow_loops_free (&loops_info); | |
282 | ||
283 | /* Clean up the CFG so that any forwarder blocks created by loop | |
284 | canonicalization are removed. */ | |
285 | cleanup_tree_cfg (); | |
8171a1dd | 286 | calculate_dominance_info (CDI_DOMINATORS); |
388d1fc1 | 287 | |
62b180e1 | 288 | /* We need accurate information regarding back edges in the CFG |
289 | for jump threading. */ | |
290 | mark_dfs_back_edges (); | |
388d1fc1 | 291 | |
62b180e1 | 292 | /* Recursively walk the dominator tree optimizing statements. */ |
293 | walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR); | |
4ee9c684 | 294 | |
62b180e1 | 295 | { |
296 | block_stmt_iterator bsi; | |
297 | basic_block bb; | |
298 | FOR_EACH_BB (bb) | |
22aa74c4 | 299 | { |
62b180e1 | 300 | for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) |
301 | update_stmt_if_modified (bsi_stmt (bsi)); | |
22aa74c4 | 302 | } |
62b180e1 | 303 | } |
0638045e | 304 | |
62b180e1 | 305 | /* If we exposed any new variables, go ahead and put them into |
306 | SSA form now, before we handle jump threading. This simplifies | |
307 | interactions between rewriting of _DECL nodes into SSA form | |
308 | and rewriting SSA_NAME nodes into SSA form after block | |
309 | duplication and CFG manipulation. */ | |
310 | update_ssa (TODO_update_ssa); | |
388d1fc1 | 311 | |
62b180e1 | 312 | free_all_edge_infos (); |
388d1fc1 | 313 | |
62b180e1 | 314 | /* Thread jumps, creating duplicate blocks as needed. */ |
315 | cfg_altered |= thread_through_all_blocks (); | |
4ee9c684 | 316 | |
62b180e1 | 317 | /* Removal of statements may make some EH edges dead. Purge |
318 | such edges from the CFG as needed. */ | |
319 | if (!bitmap_empty_p (need_eh_cleanup)) | |
320 | { | |
321 | cfg_altered |= tree_purge_all_dead_eh_edges (need_eh_cleanup); | |
322 | bitmap_zero (need_eh_cleanup); | |
323 | } | |
4ee9c684 | 324 | |
62b180e1 | 325 | if (cfg_altered) |
326 | free_dominance_info (CDI_DOMINATORS); | |
7414901f | 327 | |
62b180e1 | 328 | /* Finally, remove everything except invariants in SSA_NAME_VALUE. |
7414901f | 329 | |
62b180e1 | 330 | Long term we will be able to let everything in SSA_NAME_VALUE |
331 | persist. However, for now, we know this is the safe thing to do. */ | |
332 | for (i = 0; i < num_ssa_names; i++) | |
333 | { | |
334 | tree name = ssa_name (i); | |
335 | tree value; | |
7414901f | 336 | |
62b180e1 | 337 | if (!name) |
338 | continue; | |
7414901f | 339 | |
62b180e1 | 340 | value = SSA_NAME_VALUE (name); |
341 | if (value && !is_gimple_min_invariant (value)) | |
342 | SSA_NAME_VALUE (name) = NULL; | |
4ee9c684 | 343 | } |
4ee9c684 | 344 | |
4ee9c684 | 345 | /* Debugging dumps. */ |
346 | if (dump_file && (dump_flags & TDF_STATS)) | |
347 | dump_dominator_optimization_stats (dump_file); | |
348 | ||
62b180e1 | 349 | /* Delete our main hashtable. */ |
4ee9c684 | 350 | htab_delete (avail_exprs); |
4ee9c684 | 351 | |
352 | /* And finalize the dominator walker. */ | |
353 | fini_walk_dominator_tree (&walk_data); | |
a8ddfbad | 354 | |
8dbf774a | 355 | /* Free asserted bitmaps and stacks. */ |
27335ffd | 356 | BITMAP_FREE (need_eh_cleanup); |
486b57c7 | 357 | |
046bfc77 | 358 | VEC_free (tree, heap, avail_exprs_stack); |
359 | VEC_free (tree, heap, const_and_copies_stack); | |
046bfc77 | 360 | VEC_free (tree, heap, stmts_to_rescan); |
2a1990e9 | 361 | return 0; |
4ee9c684 | 362 | } |
363 | ||
364 | static bool | |
365 | gate_dominator (void) | |
366 | { | |
367 | return flag_tree_dom != 0; | |
368 | } | |
369 | ||
370 | struct tree_opt_pass pass_dominator = | |
371 | { | |
372 | "dom", /* name */ | |
373 | gate_dominator, /* gate */ | |
374 | tree_ssa_dominator_optimize, /* execute */ | |
375 | NULL, /* sub */ | |
376 | NULL, /* next */ | |
377 | 0, /* static_pass_number */ | |
378 | TV_TREE_SSA_DOMINATOR_OPTS, /* tv_id */ | |
f45a1ca1 | 379 | PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */ |
4ee9c684 | 380 | 0, /* properties_provided */ |
eff665b7 | 381 | PROP_smt_usage, /* properties_destroyed */ |
4ee9c684 | 382 | 0, /* todo_flags_start */ |
88dbf20f | 383 | TODO_dump_func |
384 | | TODO_update_ssa | |
62b180e1 | 385 | | TODO_cleanup_cfg |
de08b454 | 386 | | TODO_verify_ssa |
eff665b7 | 387 | | TODO_update_smt_usage, /* todo_flags_finish */ |
0f9005dd | 388 | 0 /* letter */ |
4ee9c684 | 389 | }; |
390 | ||
391 | ||
54aceb26 | 392 | /* Given a stmt CONDSTMT containing a COND_EXPR, canonicalize the |
393 | COND_EXPR into a canonical form. */ | |
394 | ||
395 | static void | |
396 | canonicalize_comparison (tree condstmt) | |
397 | { | |
398 | tree cond = COND_EXPR_COND (condstmt); | |
399 | tree op0; | |
400 | tree op1; | |
401 | enum tree_code code = TREE_CODE (cond); | |
402 | ||
403 | if (!COMPARISON_CLASS_P (cond)) | |
404 | return; | |
405 | ||
406 | op0 = TREE_OPERAND (cond, 0); | |
407 | op1 = TREE_OPERAND (cond, 1); | |
408 | ||
409 | /* If it would be profitable to swap the operands, then do so to | |
410 | canonicalize the statement, enabling better optimization. | |
411 | ||
412 | By placing canonicalization of such expressions here we | |
413 | transparently keep statements in canonical form, even | |
414 | when the statement is modified. */ | |
415 | if (tree_swap_operands_p (op0, op1, false)) | |
416 | { | |
417 | /* For relationals we need to swap the operands | |
418 | and change the code. */ | |
419 | if (code == LT_EXPR | |
420 | || code == GT_EXPR | |
421 | || code == LE_EXPR | |
422 | || code == GE_EXPR) | |
423 | { | |
424 | TREE_SET_CODE (cond, swap_tree_comparison (code)); | |
425 | swap_tree_operands (condstmt, | |
426 | &TREE_OPERAND (cond, 0), | |
427 | &TREE_OPERAND (cond, 1)); | |
428 | /* If one operand was in the operand cache, but the other is | |
429 | not, because it is a constant, this is a case that the | |
430 | internal updating code of swap_tree_operands can't handle | |
431 | properly. */ | |
432 | if (TREE_CODE_CLASS (TREE_CODE (op0)) | |
433 | != TREE_CODE_CLASS (TREE_CODE (op1))) | |
434 | update_stmt (condstmt); | |
435 | } | |
436 | } | |
437 | } | |
4ee9c684 | 438 | |
4ee9c684 | 439 | /* Initialize local stacks for this optimizer and record equivalences |
440 | upon entry to BB. Equivalences can come from the edge traversed to | |
441 | reach BB or they may come from PHI nodes at the start of BB. */ | |
442 | ||
443 | static void | |
2f0993e7 | 444 | dom_opt_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
445 | basic_block bb) | |
4ee9c684 | 446 | { |
447 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
448 | fprintf (dump_file, "\n\nOptimizing block #%d\n\n", bb->index); | |
449 | ||
dd2d357d | 450 | /* Push a marker on the stacks of local information so that we know how |
451 | far to unwind when we finalize this block. */ | |
046bfc77 | 452 | VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE); |
046bfc77 | 453 | VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); |
9c629f0e | 454 | |
2f0993e7 | 455 | record_equivalences_from_incoming_edge (bb); |
4ee9c684 | 456 | |
457 | /* PHI nodes can create equivalences too. */ | |
2f0993e7 | 458 | record_equivalences_from_phis (bb); |
4ee9c684 | 459 | } |
460 | ||
461 | /* Given an expression EXPR (a relational expression or a statement), | |
5206b159 | 462 | initialize the hash table element pointed to by ELEMENT. */ |
4ee9c684 | 463 | |
464 | static void | |
465 | initialize_hash_element (tree expr, tree lhs, struct expr_hash_elt *element) | |
466 | { | |
467 | /* Hash table elements may be based on conditional expressions or statements. | |
468 | ||
469 | For the former case, we have no annotation and we want to hash the | |
470 | conditional expression. In the latter case we have an annotation and | |
471 | we want to record the expression the statement evaluates. */ | |
ce45a448 | 472 | if (COMPARISON_CLASS_P (expr) || TREE_CODE (expr) == TRUTH_NOT_EXPR) |
4ee9c684 | 473 | { |
b66731e8 | 474 | element->stmt = NULL; |
4ee9c684 | 475 | element->rhs = expr; |
476 | } | |
477 | else if (TREE_CODE (expr) == COND_EXPR) | |
478 | { | |
b66731e8 | 479 | element->stmt = expr; |
4ee9c684 | 480 | element->rhs = COND_EXPR_COND (expr); |
481 | } | |
482 | else if (TREE_CODE (expr) == SWITCH_EXPR) | |
483 | { | |
b66731e8 | 484 | element->stmt = expr; |
4ee9c684 | 485 | element->rhs = SWITCH_COND (expr); |
486 | } | |
487 | else if (TREE_CODE (expr) == RETURN_EXPR && TREE_OPERAND (expr, 0)) | |
488 | { | |
b66731e8 | 489 | element->stmt = expr; |
4ee9c684 | 490 | element->rhs = TREE_OPERAND (TREE_OPERAND (expr, 0), 1); |
491 | } | |
a01d0a8b | 492 | else if (TREE_CODE (expr) == GOTO_EXPR) |
493 | { | |
b66731e8 | 494 | element->stmt = expr; |
a01d0a8b | 495 | element->rhs = GOTO_DESTINATION (expr); |
496 | } | |
4ee9c684 | 497 | else |
498 | { | |
b66731e8 | 499 | element->stmt = expr; |
4ee9c684 | 500 | element->rhs = TREE_OPERAND (expr, 1); |
501 | } | |
502 | ||
503 | element->lhs = lhs; | |
504 | element->hash = avail_expr_hash (element); | |
505 | } | |
506 | ||
507 | /* Remove all the expressions in LOCALS from TABLE, stopping when there are | |
508 | LIMIT entries left in LOCALs. */ | |
509 | ||
510 | static void | |
9c629f0e | 511 | remove_local_expressions_from_table (void) |
4ee9c684 | 512 | { |
4ee9c684 | 513 | /* Remove all the expressions made available in this block. */ |
046bfc77 | 514 | while (VEC_length (tree, avail_exprs_stack) > 0) |
4ee9c684 | 515 | { |
516 | struct expr_hash_elt element; | |
046bfc77 | 517 | tree expr = VEC_pop (tree, avail_exprs_stack); |
9c629f0e | 518 | |
519 | if (expr == NULL_TREE) | |
520 | break; | |
4ee9c684 | 521 | |
522 | initialize_hash_element (expr, NULL, &element); | |
9c629f0e | 523 | htab_remove_elt_with_hash (avail_exprs, &element, element.hash); |
4ee9c684 | 524 | } |
525 | } | |
526 | ||
da43203c | 527 | /* Use the source/dest pairs in CONST_AND_COPIES_STACK to restore |
528 | CONST_AND_COPIES to its original state, stopping when we hit a | |
529 | NULL marker. */ | |
4ee9c684 | 530 | |
531 | static void | |
da43203c | 532 | restore_vars_to_original_value (void) |
4ee9c684 | 533 | { |
046bfc77 | 534 | while (VEC_length (tree, const_and_copies_stack) > 0) |
4ee9c684 | 535 | { |
536 | tree prev_value, dest; | |
537 | ||
046bfc77 | 538 | dest = VEC_pop (tree, const_and_copies_stack); |
4ee9c684 | 539 | |
da43203c | 540 | if (dest == NULL) |
541 | break; | |
542 | ||
046bfc77 | 543 | prev_value = VEC_pop (tree, const_and_copies_stack); |
4c7a0518 | 544 | SSA_NAME_VALUE (dest) = prev_value; |
4ee9c684 | 545 | } |
546 | } | |
547 | ||
62b180e1 | 548 | /* A trivial wrapper so that we can present the generic jump |
549 | threading code with a simple API for simplifying statements. */ | |
550 | static tree | |
551 | simplify_stmt_for_jump_threading (tree stmt) | |
552 | { | |
553 | return lookup_avail_expr (stmt, false); | |
554 | } | |
555 | ||
556 | /* Wrapper for common code to attempt to thread an edge. For example, | |
557 | it handles lazily building the dummy condition and the bookkeeping | |
558 | when jump threading is successful. */ | |
559 | ||
560 | static void | |
561 | dom_thread_across_edge (struct dom_walk_data *walk_data, edge e) | |
562 | { | |
563 | /* If we don't already have a dummy condition, build it now. */ | |
564 | if (! walk_data->global_data) | |
565 | { | |
15348a37 | 566 | tree dummy_cond = build2 (NE_EXPR, boolean_type_node, |
62b180e1 | 567 | integer_zero_node, integer_zero_node); |
568 | dummy_cond = build3 (COND_EXPR, void_type_node, dummy_cond, NULL, NULL); | |
569 | walk_data->global_data = dummy_cond; | |
570 | } | |
571 | ||
572 | thread_across_edge (walk_data->global_data, e, false, | |
573 | &const_and_copies_stack, | |
574 | simplify_stmt_for_jump_threading); | |
575 | } | |
576 | ||
4ee9c684 | 577 | /* We have finished processing the dominator children of BB, perform |
578 | any finalization actions in preparation for leaving this node in | |
579 | the dominator tree. */ | |
580 | ||
581 | static void | |
582 | dom_opt_finalize_block (struct dom_walk_data *walk_data, basic_block bb) | |
583 | { | |
4ee9c684 | 584 | tree last; |
585 | ||
62b180e1 | 586 | |
2080a2d5 | 587 | /* If we have an outgoing edge to a block with multiple incoming and |
588 | outgoing edges, then we may be able to thread the edge. ie, we | |
589 | may be able to statically determine which of the outgoing edges | |
590 | will be traversed when the incoming edge from BB is traversed. */ | |
ea091dfd | 591 | if (single_succ_p (bb) |
592 | && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0 | |
62b180e1 | 593 | && potentially_threadable_block (single_succ (bb))) |
4ee9c684 | 594 | { |
62b180e1 | 595 | dom_thread_across_edge (walk_data, single_succ_edge (bb)); |
4ee9c684 | 596 | } |
597 | else if ((last = last_stmt (bb)) | |
598 | && TREE_CODE (last) == COND_EXPR | |
ce45a448 | 599 | && (COMPARISON_CLASS_P (COND_EXPR_COND (last)) |
4ee9c684 | 600 | || TREE_CODE (COND_EXPR_COND (last)) == SSA_NAME) |
cd665a06 | 601 | && EDGE_COUNT (bb->succs) == 2 |
602 | && (EDGE_SUCC (bb, 0)->flags & EDGE_ABNORMAL) == 0 | |
603 | && (EDGE_SUCC (bb, 1)->flags & EDGE_ABNORMAL) == 0) | |
4ee9c684 | 604 | { |
605 | edge true_edge, false_edge; | |
4ee9c684 | 606 | |
607 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
608 | ||
2080a2d5 | 609 | /* Only try to thread the edge if it reaches a target block with |
610 | more than one predecessor and more than one successor. */ | |
62b180e1 | 611 | if (potentially_threadable_block (true_edge->dest)) |
4ee9c684 | 612 | { |
2f0993e7 | 613 | struct edge_info *edge_info; |
614 | unsigned int i; | |
615 | ||
9c629f0e | 616 | /* Push a marker onto the available expression stack so that we |
617 | unwind any expressions related to the TRUE arm before processing | |
618 | the false arm below. */ | |
046bfc77 | 619 | VEC_safe_push (tree, heap, avail_exprs_stack, NULL_TREE); |
046bfc77 | 620 | VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); |
9c629f0e | 621 | |
945865c5 | 622 | edge_info = (struct edge_info *) true_edge->aux; |
2f0993e7 | 623 | |
624 | /* If we have info associated with this edge, record it into | |
625 | our equivalency tables. */ | |
626 | if (edge_info) | |
4ee9c684 | 627 | { |
2f0993e7 | 628 | tree *cond_equivalences = edge_info->cond_equivalences; |
629 | tree lhs = edge_info->lhs; | |
630 | tree rhs = edge_info->rhs; | |
631 | ||
a01d0a8b | 632 | /* If we have a simple NAME = VALUE equivalency record it. */ |
633 | if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
2f0993e7 | 634 | record_const_or_copy (lhs, rhs); |
635 | ||
636 | /* If we have 0 = COND or 1 = COND equivalences, record them | |
637 | into our expression hash tables. */ | |
638 | if (cond_equivalences) | |
639 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) | |
640 | { | |
641 | tree expr = cond_equivalences[i]; | |
642 | tree value = cond_equivalences[i + 1]; | |
643 | ||
644 | record_cond (expr, value); | |
645 | } | |
4ee9c684 | 646 | } |
4ee9c684 | 647 | |
62b180e1 | 648 | dom_thread_across_edge (walk_data, true_edge); |
4ee9c684 | 649 | |
650 | /* And restore the various tables to their state before | |
651 | we threaded this edge. */ | |
9c629f0e | 652 | remove_local_expressions_from_table (); |
4ee9c684 | 653 | } |
654 | ||
655 | /* Similarly for the ELSE arm. */ | |
62b180e1 | 656 | if (potentially_threadable_block (false_edge->dest)) |
4ee9c684 | 657 | { |
2f0993e7 | 658 | struct edge_info *edge_info; |
659 | unsigned int i; | |
660 | ||
62b180e1 | 661 | VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); |
945865c5 | 662 | edge_info = (struct edge_info *) false_edge->aux; |
2f0993e7 | 663 | |
664 | /* If we have info associated with this edge, record it into | |
665 | our equivalency tables. */ | |
666 | if (edge_info) | |
4ee9c684 | 667 | { |
2f0993e7 | 668 | tree *cond_equivalences = edge_info->cond_equivalences; |
669 | tree lhs = edge_info->lhs; | |
670 | tree rhs = edge_info->rhs; | |
671 | ||
a01d0a8b | 672 | /* If we have a simple NAME = VALUE equivalency record it. */ |
673 | if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
2f0993e7 | 674 | record_const_or_copy (lhs, rhs); |
675 | ||
676 | /* If we have 0 = COND or 1 = COND equivalences, record them | |
677 | into our expression hash tables. */ | |
678 | if (cond_equivalences) | |
679 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) | |
680 | { | |
681 | tree expr = cond_equivalences[i]; | |
682 | tree value = cond_equivalences[i + 1]; | |
683 | ||
684 | record_cond (expr, value); | |
685 | } | |
4ee9c684 | 686 | } |
4ee9c684 | 687 | |
62b180e1 | 688 | /* Now thread the edge. */ |
689 | dom_thread_across_edge (walk_data, false_edge); | |
4ee9c684 | 690 | |
691 | /* No need to remove local expressions from our tables | |
692 | or restore vars to their original value as that will | |
693 | be done immediately below. */ | |
694 | } | |
695 | } | |
696 | ||
9c629f0e | 697 | remove_local_expressions_from_table (); |
da43203c | 698 | restore_vars_to_original_value (); |
4ee9c684 | 699 | |
a721131d | 700 | /* If we queued any statements to rescan in this block, then |
701 | go ahead and rescan them now. */ | |
046bfc77 | 702 | while (VEC_length (tree, stmts_to_rescan) > 0) |
4ee9c684 | 703 | { |
046bfc77 | 704 | tree stmt = VEC_last (tree, stmts_to_rescan); |
a721131d | 705 | basic_block stmt_bb = bb_for_stmt (stmt); |
706 | ||
707 | if (stmt_bb != bb) | |
708 | break; | |
709 | ||
046bfc77 | 710 | VEC_pop (tree, stmts_to_rescan); |
88dbf20f | 711 | mark_new_vars_to_rename (stmt); |
4ee9c684 | 712 | } |
713 | } | |
714 | ||
715 | /* PHI nodes can create equivalences too. | |
716 | ||
717 | Ignoring any alternatives which are the same as the result, if | |
718 | all the alternatives are equal, then the PHI node creates an | |
8dbf774a | 719 | equivalence. */ |
6e9a4371 | 720 | |
4ee9c684 | 721 | static void |
2f0993e7 | 722 | record_equivalences_from_phis (basic_block bb) |
4ee9c684 | 723 | { |
4ee9c684 | 724 | tree phi; |
725 | ||
04f8eea3 | 726 | for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) |
4ee9c684 | 727 | { |
728 | tree lhs = PHI_RESULT (phi); | |
729 | tree rhs = NULL; | |
730 | int i; | |
731 | ||
732 | for (i = 0; i < PHI_NUM_ARGS (phi); i++) | |
733 | { | |
734 | tree t = PHI_ARG_DEF (phi, i); | |
735 | ||
2fb4af30 | 736 | /* Ignore alternatives which are the same as our LHS. Since |
737 | LHS is a PHI_RESULT, it is known to be a SSA_NAME, so we | |
738 | can simply compare pointers. */ | |
fcf57fc2 | 739 | if (lhs == t) |
92527855 | 740 | continue; |
741 | ||
742 | /* If we have not processed an alternative yet, then set | |
743 | RHS to this alternative. */ | |
744 | if (rhs == NULL) | |
745 | rhs = t; | |
746 | /* If we have processed an alternative (stored in RHS), then | |
747 | see if it is equal to this one. If it isn't, then stop | |
748 | the search. */ | |
749 | else if (! operand_equal_for_phi_arg_p (rhs, t)) | |
4ee9c684 | 750 | break; |
751 | } | |
752 | ||
753 | /* If we had no interesting alternatives, then all the RHS alternatives | |
754 | must have been the same as LHS. */ | |
755 | if (!rhs) | |
756 | rhs = lhs; | |
757 | ||
758 | /* If we managed to iterate through each PHI alternative without | |
759 | breaking out of the loop, then we have a PHI which may create | |
760 | a useful equivalence. We do not need to record unwind data for | |
761 | this, since this is a true assignment and not an equivalence | |
365db11e | 762 | inferred from a comparison. All uses of this ssa name are dominated |
4ee9c684 | 763 | by this assignment, so unwinding just costs time and space. */ |
764 | if (i == PHI_NUM_ARGS (phi) | |
765 | && may_propagate_copy (lhs, rhs)) | |
4c7a0518 | 766 | SSA_NAME_VALUE (lhs) = rhs; |
4ee9c684 | 767 | } |
768 | } | |
769 | ||
c0735efa | 770 | /* Ignoring loop backedges, if BB has precisely one incoming edge then |
771 | return that edge. Otherwise return NULL. */ | |
772 | static edge | |
773 | single_incoming_edge_ignoring_loop_edges (basic_block bb) | |
774 | { | |
775 | edge retval = NULL; | |
776 | edge e; | |
cd665a06 | 777 | edge_iterator ei; |
c0735efa | 778 | |
cd665a06 | 779 | FOR_EACH_EDGE (e, ei, bb->preds) |
c0735efa | 780 | { |
781 | /* A loop back edge can be identified by the destination of | |
782 | the edge dominating the source of the edge. */ | |
783 | if (dominated_by_p (CDI_DOMINATORS, e->src, e->dest)) | |
784 | continue; | |
785 | ||
786 | /* If we have already seen a non-loop edge, then we must have | |
787 | multiple incoming non-loop edges and thus we return NULL. */ | |
788 | if (retval) | |
789 | return NULL; | |
790 | ||
791 | /* This is the first non-loop incoming edge we have found. Record | |
792 | it. */ | |
793 | retval = e; | |
794 | } | |
795 | ||
796 | return retval; | |
797 | } | |
798 | ||
4ee9c684 | 799 | /* Record any equivalences created by the incoming edge to BB. If BB |
800 | has more than one incoming edge, then no equivalence is created. */ | |
801 | ||
802 | static void | |
2f0993e7 | 803 | record_equivalences_from_incoming_edge (basic_block bb) |
4ee9c684 | 804 | { |
2f0993e7 | 805 | edge e; |
4ee9c684 | 806 | basic_block parent; |
2f0993e7 | 807 | struct edge_info *edge_info; |
4ee9c684 | 808 | |
0975351b | 809 | /* If our parent block ended with a control statement, then we may be |
4ee9c684 | 810 | able to record some equivalences based on which outgoing edge from |
811 | the parent was followed. */ | |
812 | parent = get_immediate_dominator (CDI_DOMINATORS, bb); | |
4ee9c684 | 813 | |
2f0993e7 | 814 | e = single_incoming_edge_ignoring_loop_edges (bb); |
4ee9c684 | 815 | |
2f0993e7 | 816 | /* If we had a single incoming edge from our parent block, then enter |
817 | any data associated with the edge into our tables. */ | |
818 | if (e && e->src == parent) | |
4ee9c684 | 819 | { |
2f0993e7 | 820 | unsigned int i; |
4ee9c684 | 821 | |
945865c5 | 822 | edge_info = (struct edge_info *) e->aux; |
4ee9c684 | 823 | |
2f0993e7 | 824 | if (edge_info) |
4ee9c684 | 825 | { |
2f0993e7 | 826 | tree lhs = edge_info->lhs; |
827 | tree rhs = edge_info->rhs; | |
828 | tree *cond_equivalences = edge_info->cond_equivalences; | |
829 | ||
830 | if (lhs) | |
831 | record_equality (lhs, rhs); | |
832 | ||
833 | if (cond_equivalences) | |
4ee9c684 | 834 | { |
2f0993e7 | 835 | for (i = 0; i < edge_info->max_cond_equivalences; i += 2) |
4ee9c684 | 836 | { |
2f0993e7 | 837 | tree expr = cond_equivalences[i]; |
838 | tree value = cond_equivalences[i + 1]; | |
839 | ||
840 | record_cond (expr, value); | |
4ee9c684 | 841 | } |
842 | } | |
4ee9c684 | 843 | } |
844 | } | |
4ee9c684 | 845 | } |
846 | ||
847 | /* Dump SSA statistics on FILE. */ | |
848 | ||
849 | void | |
850 | dump_dominator_optimization_stats (FILE *file) | |
851 | { | |
852 | long n_exprs; | |
853 | ||
854 | fprintf (file, "Total number of statements: %6ld\n\n", | |
855 | opt_stats.num_stmts); | |
856 | fprintf (file, "Exprs considered for dominator optimizations: %6ld\n", | |
857 | opt_stats.num_exprs_considered); | |
858 | ||
859 | n_exprs = opt_stats.num_exprs_considered; | |
860 | if (n_exprs == 0) | |
861 | n_exprs = 1; | |
862 | ||
863 | fprintf (file, " Redundant expressions eliminated: %6ld (%.0f%%)\n", | |
864 | opt_stats.num_re, PERCENT (opt_stats.num_re, | |
865 | n_exprs)); | |
88dbf20f | 866 | fprintf (file, " Constants propagated: %6ld\n", |
867 | opt_stats.num_const_prop); | |
868 | fprintf (file, " Copies propagated: %6ld\n", | |
869 | opt_stats.num_copy_prop); | |
4ee9c684 | 870 | |
871 | fprintf (file, "\nHash table statistics:\n"); | |
872 | ||
873 | fprintf (file, " avail_exprs: "); | |
874 | htab_statistics (file, avail_exprs); | |
875 | } | |
876 | ||
877 | ||
878 | /* Dump SSA statistics on stderr. */ | |
879 | ||
880 | void | |
881 | debug_dominator_optimization_stats (void) | |
882 | { | |
883 | dump_dominator_optimization_stats (stderr); | |
884 | } | |
885 | ||
886 | ||
887 | /* Dump statistics for the hash table HTAB. */ | |
888 | ||
889 | static void | |
890 | htab_statistics (FILE *file, htab_t htab) | |
891 | { | |
892 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
893 | (long) htab_size (htab), | |
894 | (long) htab_elements (htab), | |
895 | htab_collisions (htab)); | |
896 | } | |
897 | ||
4ee9c684 | 898 | /* Enter a statement into the true/false expression hash table indicating |
899 | that the condition COND has the value VALUE. */ | |
900 | ||
901 | static void | |
9c629f0e | 902 | record_cond (tree cond, tree value) |
4ee9c684 | 903 | { |
945865c5 | 904 | struct expr_hash_elt *element = XCNEW (struct expr_hash_elt); |
4ee9c684 | 905 | void **slot; |
906 | ||
907 | initialize_hash_element (cond, value, element); | |
908 | ||
909 | slot = htab_find_slot_with_hash (avail_exprs, (void *)element, | |
67c4f309 | 910 | element->hash, INSERT); |
4ee9c684 | 911 | if (*slot == NULL) |
912 | { | |
913 | *slot = (void *) element; | |
046bfc77 | 914 | VEC_safe_push (tree, heap, avail_exprs_stack, cond); |
4ee9c684 | 915 | } |
916 | else | |
917 | free (element); | |
918 | } | |
919 | ||
2f0993e7 | 920 | /* Build a new conditional using NEW_CODE, OP0 and OP1 and store |
921 | the new conditional into *p, then store a boolean_true_node | |
822e391f | 922 | into *(p + 1). */ |
2f0993e7 | 923 | |
924 | static void | |
925 | build_and_record_new_cond (enum tree_code new_code, tree op0, tree op1, tree *p) | |
926 | { | |
927 | *p = build2 (new_code, boolean_type_node, op0, op1); | |
928 | p++; | |
929 | *p = boolean_true_node; | |
930 | } | |
931 | ||
932 | /* Record that COND is true and INVERTED is false into the edge information | |
933 | structure. Also record that any conditions dominated by COND are true | |
934 | as well. | |
043d0665 | 935 | |
936 | For example, if a < b is true, then a <= b must also be true. */ | |
937 | ||
938 | static void | |
2f0993e7 | 939 | record_conditions (struct edge_info *edge_info, tree cond, tree inverted) |
043d0665 | 940 | { |
2f0993e7 | 941 | tree op0, op1; |
942 | ||
943 | if (!COMPARISON_CLASS_P (cond)) | |
944 | return; | |
945 | ||
946 | op0 = TREE_OPERAND (cond, 0); | |
947 | op1 = TREE_OPERAND (cond, 1); | |
948 | ||
043d0665 | 949 | switch (TREE_CODE (cond)) |
950 | { | |
951 | case LT_EXPR: | |
043d0665 | 952 | case GT_EXPR: |
2f0993e7 | 953 | edge_info->max_cond_equivalences = 12; |
945865c5 | 954 | edge_info->cond_equivalences = XNEWVEC (tree, 12); |
2f0993e7 | 955 | build_and_record_new_cond ((TREE_CODE (cond) == LT_EXPR |
956 | ? LE_EXPR : GE_EXPR), | |
957 | op0, op1, &edge_info->cond_equivalences[4]); | |
958 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
959 | &edge_info->cond_equivalences[6]); | |
960 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
961 | &edge_info->cond_equivalences[8]); | |
962 | build_and_record_new_cond (LTGT_EXPR, op0, op1, | |
963 | &edge_info->cond_equivalences[10]); | |
043d0665 | 964 | break; |
965 | ||
966 | case GE_EXPR: | |
967 | case LE_EXPR: | |
2f0993e7 | 968 | edge_info->max_cond_equivalences = 6; |
945865c5 | 969 | edge_info->cond_equivalences = XNEWVEC (tree, 6); |
2f0993e7 | 970 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, |
971 | &edge_info->cond_equivalences[4]); | |
043d0665 | 972 | break; |
973 | ||
974 | case EQ_EXPR: | |
2f0993e7 | 975 | edge_info->max_cond_equivalences = 10; |
945865c5 | 976 | edge_info->cond_equivalences = XNEWVEC (tree, 10); |
2f0993e7 | 977 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, |
978 | &edge_info->cond_equivalences[4]); | |
979 | build_and_record_new_cond (LE_EXPR, op0, op1, | |
980 | &edge_info->cond_equivalences[6]); | |
981 | build_and_record_new_cond (GE_EXPR, op0, op1, | |
982 | &edge_info->cond_equivalences[8]); | |
043d0665 | 983 | break; |
984 | ||
985 | case UNORDERED_EXPR: | |
2f0993e7 | 986 | edge_info->max_cond_equivalences = 16; |
945865c5 | 987 | edge_info->cond_equivalences = XNEWVEC (tree, 16); |
2f0993e7 | 988 | build_and_record_new_cond (NE_EXPR, op0, op1, |
989 | &edge_info->cond_equivalences[4]); | |
990 | build_and_record_new_cond (UNLE_EXPR, op0, op1, | |
991 | &edge_info->cond_equivalences[6]); | |
992 | build_and_record_new_cond (UNGE_EXPR, op0, op1, | |
993 | &edge_info->cond_equivalences[8]); | |
994 | build_and_record_new_cond (UNEQ_EXPR, op0, op1, | |
995 | &edge_info->cond_equivalences[10]); | |
996 | build_and_record_new_cond (UNLT_EXPR, op0, op1, | |
997 | &edge_info->cond_equivalences[12]); | |
998 | build_and_record_new_cond (UNGT_EXPR, op0, op1, | |
999 | &edge_info->cond_equivalences[14]); | |
043d0665 | 1000 | break; |
1001 | ||
1002 | case UNLT_EXPR: | |
043d0665 | 1003 | case UNGT_EXPR: |
2f0993e7 | 1004 | edge_info->max_cond_equivalences = 8; |
945865c5 | 1005 | edge_info->cond_equivalences = XNEWVEC (tree, 8); |
2f0993e7 | 1006 | build_and_record_new_cond ((TREE_CODE (cond) == UNLT_EXPR |
1007 | ? UNLE_EXPR : UNGE_EXPR), | |
1008 | op0, op1, &edge_info->cond_equivalences[4]); | |
1009 | build_and_record_new_cond (NE_EXPR, op0, op1, | |
1010 | &edge_info->cond_equivalences[6]); | |
043d0665 | 1011 | break; |
1012 | ||
1013 | case UNEQ_EXPR: | |
2f0993e7 | 1014 | edge_info->max_cond_equivalences = 8; |
945865c5 | 1015 | edge_info->cond_equivalences = XNEWVEC (tree, 8); |
2f0993e7 | 1016 | build_and_record_new_cond (UNLE_EXPR, op0, op1, |
1017 | &edge_info->cond_equivalences[4]); | |
1018 | build_and_record_new_cond (UNGE_EXPR, op0, op1, | |
1019 | &edge_info->cond_equivalences[6]); | |
043d0665 | 1020 | break; |
1021 | ||
1022 | case LTGT_EXPR: | |
2f0993e7 | 1023 | edge_info->max_cond_equivalences = 8; |
945865c5 | 1024 | edge_info->cond_equivalences = XNEWVEC (tree, 8); |
2f0993e7 | 1025 | build_and_record_new_cond (NE_EXPR, op0, op1, |
1026 | &edge_info->cond_equivalences[4]); | |
1027 | build_and_record_new_cond (ORDERED_EXPR, op0, op1, | |
1028 | &edge_info->cond_equivalences[6]); | |
1029 | break; | |
043d0665 | 1030 | |
1031 | default: | |
2f0993e7 | 1032 | edge_info->max_cond_equivalences = 4; |
945865c5 | 1033 | edge_info->cond_equivalences = XNEWVEC (tree, 4); |
043d0665 | 1034 | break; |
1035 | } | |
2f0993e7 | 1036 | |
1037 | /* Now store the original true and false conditions into the first | |
1038 | two slots. */ | |
1039 | edge_info->cond_equivalences[0] = cond; | |
1040 | edge_info->cond_equivalences[1] = boolean_true_node; | |
1041 | edge_info->cond_equivalences[2] = inverted; | |
1042 | edge_info->cond_equivalences[3] = boolean_false_node; | |
043d0665 | 1043 | } |
1044 | ||
4ee9c684 | 1045 | /* A helper function for record_const_or_copy and record_equality. |
1046 | Do the work of recording the value and undo info. */ | |
1047 | ||
1048 | static void | |
da43203c | 1049 | record_const_or_copy_1 (tree x, tree y, tree prev_x) |
4ee9c684 | 1050 | { |
4c7a0518 | 1051 | SSA_NAME_VALUE (x) = y; |
4ee9c684 | 1052 | |
046bfc77 | 1053 | VEC_reserve (tree, heap, const_and_copies_stack, 2); |
1054 | VEC_quick_push (tree, const_and_copies_stack, prev_x); | |
1055 | VEC_quick_push (tree, const_and_copies_stack, x); | |
4ee9c684 | 1056 | } |
1057 | ||
ba4c299c | 1058 | |
1059 | /* Return the loop depth of the basic block of the defining statement of X. | |
1060 | This number should not be treated as absolutely correct because the loop | |
1061 | information may not be completely up-to-date when dom runs. However, it | |
1062 | will be relatively correct, and as more passes are taught to keep loop info | |
1063 | up to date, the result will become more and more accurate. */ | |
1064 | ||
88dbf20f | 1065 | int |
ba4c299c | 1066 | loop_depth_of_name (tree x) |
1067 | { | |
1068 | tree defstmt; | |
1069 | basic_block defbb; | |
1070 | ||
1071 | /* If it's not an SSA_NAME, we have no clue where the definition is. */ | |
1072 | if (TREE_CODE (x) != SSA_NAME) | |
1073 | return 0; | |
1074 | ||
1075 | /* Otherwise return the loop depth of the defining statement's bb. | |
1076 | Note that there may not actually be a bb for this statement, if the | |
1077 | ssa_name is live on entry. */ | |
1078 | defstmt = SSA_NAME_DEF_STMT (x); | |
1079 | defbb = bb_for_stmt (defstmt); | |
1080 | if (!defbb) | |
1081 | return 0; | |
1082 | ||
1083 | return defbb->loop_depth; | |
1084 | } | |
1085 | ||
1086 | ||
4ee9c684 | 1087 | /* Record that X is equal to Y in const_and_copies. Record undo |
f0458177 | 1088 | information in the block-local vector. */ |
4ee9c684 | 1089 | |
1090 | static void | |
da43203c | 1091 | record_const_or_copy (tree x, tree y) |
4ee9c684 | 1092 | { |
4c7a0518 | 1093 | tree prev_x = SSA_NAME_VALUE (x); |
4ee9c684 | 1094 | |
1095 | if (TREE_CODE (y) == SSA_NAME) | |
1096 | { | |
4c7a0518 | 1097 | tree tmp = SSA_NAME_VALUE (y); |
4ee9c684 | 1098 | if (tmp) |
1099 | y = tmp; | |
1100 | } | |
1101 | ||
da43203c | 1102 | record_const_or_copy_1 (x, y, prev_x); |
4ee9c684 | 1103 | } |
1104 | ||
1105 | /* Similarly, but assume that X and Y are the two operands of an EQ_EXPR. | |
1106 | This constrains the cases in which we may treat this as assignment. */ | |
1107 | ||
1108 | static void | |
da43203c | 1109 | record_equality (tree x, tree y) |
4ee9c684 | 1110 | { |
1111 | tree prev_x = NULL, prev_y = NULL; | |
1112 | ||
1113 | if (TREE_CODE (x) == SSA_NAME) | |
4c7a0518 | 1114 | prev_x = SSA_NAME_VALUE (x); |
4ee9c684 | 1115 | if (TREE_CODE (y) == SSA_NAME) |
4c7a0518 | 1116 | prev_y = SSA_NAME_VALUE (y); |
4ee9c684 | 1117 | |
ba4c299c | 1118 | /* If one of the previous values is invariant, or invariant in more loops |
1119 | (by depth), then use that. | |
4ee9c684 | 1120 | Otherwise it doesn't matter which value we choose, just so |
1121 | long as we canonicalize on one value. */ | |
1122 | if (TREE_INVARIANT (y)) | |
1123 | ; | |
ba4c299c | 1124 | else if (TREE_INVARIANT (x) || (loop_depth_of_name (x) <= loop_depth_of_name (y))) |
4ee9c684 | 1125 | prev_x = x, x = y, y = prev_x, prev_x = prev_y; |
1126 | else if (prev_x && TREE_INVARIANT (prev_x)) | |
1127 | x = y, y = prev_x, prev_x = prev_y; | |
4c7a0518 | 1128 | else if (prev_y && TREE_CODE (prev_y) != VALUE_HANDLE) |
4ee9c684 | 1129 | y = prev_y; |
1130 | ||
1131 | /* After the swapping, we must have one SSA_NAME. */ | |
1132 | if (TREE_CODE (x) != SSA_NAME) | |
1133 | return; | |
1134 | ||
1135 | /* For IEEE, -0.0 == 0.0, so we don't necessarily know the sign of a | |
1136 | variable compared against zero. If we're honoring signed zeros, | |
1137 | then we cannot record this value unless we know that the value is | |
365db11e | 1138 | nonzero. */ |
4ee9c684 | 1139 | if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (x))) |
1140 | && (TREE_CODE (y) != REAL_CST | |
1141 | || REAL_VALUES_EQUAL (dconst0, TREE_REAL_CST (y)))) | |
1142 | return; | |
1143 | ||
da43203c | 1144 | record_const_or_copy_1 (x, y, prev_x); |
4ee9c684 | 1145 | } |
1146 | ||
119a0489 | 1147 | /* Returns true when STMT is a simple iv increment. It detects the |
1148 | following situation: | |
1149 | ||
1150 | i_1 = phi (..., i_2) | |
1151 | i_2 = i_1 +/- ... */ | |
1152 | ||
1153 | static bool | |
1154 | simple_iv_increment_p (tree stmt) | |
1155 | { | |
1156 | tree lhs, rhs, preinc, phi; | |
1157 | unsigned i; | |
1158 | ||
1159 | if (TREE_CODE (stmt) != MODIFY_EXPR) | |
1160 | return false; | |
1161 | ||
1162 | lhs = TREE_OPERAND (stmt, 0); | |
1163 | if (TREE_CODE (lhs) != SSA_NAME) | |
1164 | return false; | |
1165 | ||
1166 | rhs = TREE_OPERAND (stmt, 1); | |
1167 | ||
1168 | if (TREE_CODE (rhs) != PLUS_EXPR | |
1169 | && TREE_CODE (rhs) != MINUS_EXPR) | |
1170 | return false; | |
1171 | ||
1172 | preinc = TREE_OPERAND (rhs, 0); | |
1173 | if (TREE_CODE (preinc) != SSA_NAME) | |
1174 | return false; | |
1175 | ||
1176 | phi = SSA_NAME_DEF_STMT (preinc); | |
1177 | if (TREE_CODE (phi) != PHI_NODE) | |
1178 | return false; | |
1179 | ||
1180 | for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++) | |
1181 | if (PHI_ARG_DEF (phi, i) == lhs) | |
1182 | return true; | |
1183 | ||
1184 | return false; | |
1185 | } | |
1186 | ||
591c2a30 | 1187 | /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current |
1188 | known value for that SSA_NAME (or NULL if no value is known). | |
1189 | ||
8dbf774a | 1190 | Propagate values from CONST_AND_COPIES into the PHI nodes of the |
1191 | successors of BB. */ | |
591c2a30 | 1192 | |
1193 | static void | |
8dbf774a | 1194 | cprop_into_successor_phis (basic_block bb) |
591c2a30 | 1195 | { |
1196 | edge e; | |
cd665a06 | 1197 | edge_iterator ei; |
591c2a30 | 1198 | |
cd665a06 | 1199 | FOR_EACH_EDGE (e, ei, bb->succs) |
591c2a30 | 1200 | { |
1201 | tree phi; | |
5f50f9bf | 1202 | int indx; |
591c2a30 | 1203 | |
1204 | /* If this is an abnormal edge, then we do not want to copy propagate | |
1205 | into the PHI alternative associated with this edge. */ | |
1206 | if (e->flags & EDGE_ABNORMAL) | |
1207 | continue; | |
1208 | ||
1209 | phi = phi_nodes (e->dest); | |
1210 | if (! phi) | |
1211 | continue; | |
1212 | ||
5f50f9bf | 1213 | indx = e->dest_idx; |
591c2a30 | 1214 | for ( ; phi; phi = PHI_CHAIN (phi)) |
1215 | { | |
591c2a30 | 1216 | tree new; |
1217 | use_operand_p orig_p; | |
1218 | tree orig; | |
1219 | ||
591c2a30 | 1220 | /* The alternative may be associated with a constant, so verify |
1221 | it is an SSA_NAME before doing anything with it. */ | |
5f50f9bf | 1222 | orig_p = PHI_ARG_DEF_PTR (phi, indx); |
591c2a30 | 1223 | orig = USE_FROM_PTR (orig_p); |
1224 | if (TREE_CODE (orig) != SSA_NAME) | |
1225 | continue; | |
1226 | ||
591c2a30 | 1227 | /* If we have *ORIG_P in our constant/copy table, then replace |
1228 | ORIG_P with its value in our constant/copy table. */ | |
4c7a0518 | 1229 | new = SSA_NAME_VALUE (orig); |
591c2a30 | 1230 | if (new |
88dbf20f | 1231 | && new != orig |
591c2a30 | 1232 | && (TREE_CODE (new) == SSA_NAME |
1233 | || is_gimple_min_invariant (new)) | |
1234 | && may_propagate_copy (orig, new)) | |
88dbf20f | 1235 | propagate_value (orig_p, new); |
591c2a30 | 1236 | } |
1237 | } | |
1238 | } | |
1239 | ||
2f0993e7 | 1240 | /* We have finished optimizing BB, record any information implied by |
1241 | taking a specific outgoing edge from BB. */ | |
1242 | ||
1243 | static void | |
1244 | record_edge_info (basic_block bb) | |
1245 | { | |
1246 | block_stmt_iterator bsi = bsi_last (bb); | |
1247 | struct edge_info *edge_info; | |
1248 | ||
1249 | if (! bsi_end_p (bsi)) | |
1250 | { | |
1251 | tree stmt = bsi_stmt (bsi); | |
1252 | ||
1253 | if (stmt && TREE_CODE (stmt) == SWITCH_EXPR) | |
1254 | { | |
1255 | tree cond = SWITCH_COND (stmt); | |
1256 | ||
1257 | if (TREE_CODE (cond) == SSA_NAME) | |
1258 | { | |
1259 | tree labels = SWITCH_LABELS (stmt); | |
1260 | int i, n_labels = TREE_VEC_LENGTH (labels); | |
945865c5 | 1261 | tree *info = XCNEWVEC (tree, last_basic_block); |
2f0993e7 | 1262 | edge e; |
1263 | edge_iterator ei; | |
1264 | ||
1265 | for (i = 0; i < n_labels; i++) | |
1266 | { | |
1267 | tree label = TREE_VEC_ELT (labels, i); | |
1268 | basic_block target_bb = label_to_block (CASE_LABEL (label)); | |
1269 | ||
1270 | if (CASE_HIGH (label) | |
1271 | || !CASE_LOW (label) | |
1272 | || info[target_bb->index]) | |
1273 | info[target_bb->index] = error_mark_node; | |
1274 | else | |
1275 | info[target_bb->index] = label; | |
1276 | } | |
1277 | ||
1278 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1279 | { | |
1280 | basic_block target_bb = e->dest; | |
1281 | tree node = info[target_bb->index]; | |
591c2a30 | 1282 | |
2f0993e7 | 1283 | if (node != NULL && node != error_mark_node) |
1284 | { | |
1285 | tree x = fold_convert (TREE_TYPE (cond), CASE_LOW (node)); | |
1286 | edge_info = allocate_edge_info (e); | |
1287 | edge_info->lhs = cond; | |
1288 | edge_info->rhs = x; | |
1289 | } | |
1290 | } | |
1291 | free (info); | |
1292 | } | |
1293 | } | |
1294 | ||
1295 | /* A COND_EXPR may create equivalences too. */ | |
1296 | if (stmt && TREE_CODE (stmt) == COND_EXPR) | |
1297 | { | |
1298 | tree cond = COND_EXPR_COND (stmt); | |
1299 | edge true_edge; | |
1300 | edge false_edge; | |
1301 | ||
1302 | extract_true_false_edges_from_block (bb, &true_edge, &false_edge); | |
1303 | ||
640e9781 | 1304 | /* If the conditional is a single variable 'X', record 'X = 1' |
2f0993e7 | 1305 | for the true edge and 'X = 0' on the false edge. */ |
1306 | if (SSA_VAR_P (cond)) | |
1307 | { | |
1308 | struct edge_info *edge_info; | |
1309 | ||
1310 | edge_info = allocate_edge_info (true_edge); | |
1311 | edge_info->lhs = cond; | |
1312 | edge_info->rhs = constant_boolean_node (1, TREE_TYPE (cond)); | |
1313 | ||
1314 | edge_info = allocate_edge_info (false_edge); | |
1315 | edge_info->lhs = cond; | |
1316 | edge_info->rhs = constant_boolean_node (0, TREE_TYPE (cond)); | |
1317 | } | |
1318 | /* Equality tests may create one or two equivalences. */ | |
1319 | else if (COMPARISON_CLASS_P (cond)) | |
1320 | { | |
1321 | tree op0 = TREE_OPERAND (cond, 0); | |
1322 | tree op1 = TREE_OPERAND (cond, 1); | |
1323 | ||
1324 | /* Special case comparing booleans against a constant as we | |
1325 | know the value of OP0 on both arms of the branch. i.e., we | |
1326 | can record an equivalence for OP0 rather than COND. */ | |
1327 | if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR) | |
1328 | && TREE_CODE (op0) == SSA_NAME | |
1329 | && TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE | |
1330 | && is_gimple_min_invariant (op1)) | |
1331 | { | |
1332 | if (TREE_CODE (cond) == EQ_EXPR) | |
1333 | { | |
1334 | edge_info = allocate_edge_info (true_edge); | |
1335 | edge_info->lhs = op0; | |
1336 | edge_info->rhs = (integer_zerop (op1) | |
1337 | ? boolean_false_node | |
1338 | : boolean_true_node); | |
1339 | ||
1340 | edge_info = allocate_edge_info (false_edge); | |
1341 | edge_info->lhs = op0; | |
1342 | edge_info->rhs = (integer_zerop (op1) | |
1343 | ? boolean_true_node | |
1344 | : boolean_false_node); | |
1345 | } | |
1346 | else | |
1347 | { | |
1348 | edge_info = allocate_edge_info (true_edge); | |
1349 | edge_info->lhs = op0; | |
1350 | edge_info->rhs = (integer_zerop (op1) | |
1351 | ? boolean_true_node | |
1352 | : boolean_false_node); | |
1353 | ||
1354 | edge_info = allocate_edge_info (false_edge); | |
1355 | edge_info->lhs = op0; | |
1356 | edge_info->rhs = (integer_zerop (op1) | |
1357 | ? boolean_false_node | |
1358 | : boolean_true_node); | |
1359 | } | |
1360 | } | |
1361 | ||
a07a7473 | 1362 | else if (is_gimple_min_invariant (op0) |
1363 | && (TREE_CODE (op1) == SSA_NAME | |
1364 | || is_gimple_min_invariant (op1))) | |
2f0993e7 | 1365 | { |
1366 | tree inverted = invert_truthvalue (cond); | |
1367 | struct edge_info *edge_info; | |
1368 | ||
1369 | edge_info = allocate_edge_info (true_edge); | |
1370 | record_conditions (edge_info, cond, inverted); | |
1371 | ||
1372 | if (TREE_CODE (cond) == EQ_EXPR) | |
1373 | { | |
1374 | edge_info->lhs = op1; | |
1375 | edge_info->rhs = op0; | |
1376 | } | |
1377 | ||
1378 | edge_info = allocate_edge_info (false_edge); | |
1379 | record_conditions (edge_info, inverted, cond); | |
1380 | ||
1381 | if (TREE_CODE (cond) == NE_EXPR) | |
1382 | { | |
1383 | edge_info->lhs = op1; | |
1384 | edge_info->rhs = op0; | |
1385 | } | |
1386 | } | |
1387 | ||
a07a7473 | 1388 | else if (TREE_CODE (op0) == SSA_NAME |
1389 | && (is_gimple_min_invariant (op1) | |
1390 | || TREE_CODE (op1) == SSA_NAME)) | |
2f0993e7 | 1391 | { |
1392 | tree inverted = invert_truthvalue (cond); | |
1393 | struct edge_info *edge_info; | |
1394 | ||
1395 | edge_info = allocate_edge_info (true_edge); | |
1396 | record_conditions (edge_info, cond, inverted); | |
1397 | ||
1398 | if (TREE_CODE (cond) == EQ_EXPR) | |
1399 | { | |
1400 | edge_info->lhs = op0; | |
1401 | edge_info->rhs = op1; | |
1402 | } | |
1403 | ||
1404 | edge_info = allocate_edge_info (false_edge); | |
1405 | record_conditions (edge_info, inverted, cond); | |
1406 | ||
1407 | if (TREE_CODE (cond) == NE_EXPR) | |
1408 | { | |
1409 | edge_info->lhs = op0; | |
1410 | edge_info->rhs = op1; | |
1411 | } | |
1412 | } | |
1413 | } | |
1414 | ||
1415 | /* ??? TRUTH_NOT_EXPR can create an equivalence too. */ | |
1416 | } | |
1417 | } | |
1418 | } | |
1419 | ||
1420 | /* Propagate information from BB to its outgoing edges. | |
1421 | ||
1422 | This can include equivalency information implied by control statements | |
1423 | at the end of BB and const/copy propagation into PHIs in BB's | |
1424 | successor blocks. */ | |
4ee9c684 | 1425 | |
1426 | static void | |
2f0993e7 | 1427 | propagate_to_outgoing_edges (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1428 | basic_block bb) | |
4ee9c684 | 1429 | { |
2f0993e7 | 1430 | record_edge_info (bb); |
8dbf774a | 1431 | cprop_into_successor_phis (bb); |
4ee9c684 | 1432 | } |
1433 | ||
1434 | /* Search for redundant computations in STMT. If any are found, then | |
1435 | replace them with the variable holding the result of the computation. | |
1436 | ||
1437 | If safe, record this expression into the available expression hash | |
1438 | table. */ | |
1439 | ||
1440 | static bool | |
8f628ee8 | 1441 | eliminate_redundant_computations (tree stmt) |
4ee9c684 | 1442 | { |
4ee9c684 | 1443 | tree *expr_p, def = NULL_TREE; |
1444 | bool insert = true; | |
1445 | tree cached_lhs; | |
1446 | bool retval = false; | |
f6be5aa5 | 1447 | bool modify_expr_p = false; |
4ee9c684 | 1448 | |
1449 | if (TREE_CODE (stmt) == MODIFY_EXPR) | |
1450 | def = TREE_OPERAND (stmt, 0); | |
1451 | ||
1452 | /* Certain expressions on the RHS can be optimized away, but can not | |
dac49aa5 | 1453 | themselves be entered into the hash tables. */ |
9d637cc5 | 1454 | if (! def |
4ee9c684 | 1455 | || TREE_CODE (def) != SSA_NAME |
1456 | || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def) | |
b66731e8 | 1457 | || !ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF) |
119a0489 | 1458 | /* Do not record equivalences for increments of ivs. This would create |
1459 | overlapping live ranges for a very questionable gain. */ | |
1460 | || simple_iv_increment_p (stmt)) | |
4ee9c684 | 1461 | insert = false; |
1462 | ||
1463 | /* Check if the expression has been computed before. */ | |
9c629f0e | 1464 | cached_lhs = lookup_avail_expr (stmt, insert); |
4ee9c684 | 1465 | |
4ee9c684 | 1466 | opt_stats.num_exprs_considered++; |
1467 | ||
1468 | /* Get a pointer to the expression we are trying to optimize. */ | |
1469 | if (TREE_CODE (stmt) == COND_EXPR) | |
1470 | expr_p = &COND_EXPR_COND (stmt); | |
1471 | else if (TREE_CODE (stmt) == SWITCH_EXPR) | |
1472 | expr_p = &SWITCH_COND (stmt); | |
1473 | else if (TREE_CODE (stmt) == RETURN_EXPR && TREE_OPERAND (stmt, 0)) | |
f6be5aa5 | 1474 | { |
1475 | expr_p = &TREE_OPERAND (TREE_OPERAND (stmt, 0), 1); | |
1476 | modify_expr_p = true; | |
1477 | } | |
4ee9c684 | 1478 | else |
f6be5aa5 | 1479 | { |
1480 | expr_p = &TREE_OPERAND (stmt, 1); | |
1481 | modify_expr_p = true; | |
1482 | } | |
4ee9c684 | 1483 | |
1484 | /* It is safe to ignore types here since we have already done | |
1485 | type checking in the hashing and equality routines. In fact | |
1486 | type checking here merely gets in the way of constant | |
1487 | propagation. Also, make sure that it is safe to propagate | |
1488 | CACHED_LHS into *EXPR_P. */ | |
1489 | if (cached_lhs | |
f6be5aa5 | 1490 | && ((TREE_CODE (cached_lhs) != SSA_NAME |
1491 | && (modify_expr_p | |
1492 | || tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p), | |
1493 | TREE_TYPE (cached_lhs)))) | |
591c2a30 | 1494 | || may_propagate_copy (*expr_p, cached_lhs))) |
4ee9c684 | 1495 | { |
1496 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1497 | { | |
1498 | fprintf (dump_file, " Replaced redundant expr '"); | |
1499 | print_generic_expr (dump_file, *expr_p, dump_flags); | |
1500 | fprintf (dump_file, "' with '"); | |
1501 | print_generic_expr (dump_file, cached_lhs, dump_flags); | |
1502 | fprintf (dump_file, "'\n"); | |
1503 | } | |
1504 | ||
1505 | opt_stats.num_re++; | |
1506 | ||
1507 | #if defined ENABLE_CHECKING | |
8c0963c4 | 1508 | gcc_assert (TREE_CODE (cached_lhs) == SSA_NAME |
1509 | || is_gimple_min_invariant (cached_lhs)); | |
4ee9c684 | 1510 | #endif |
1511 | ||
1512 | if (TREE_CODE (cached_lhs) == ADDR_EXPR | |
1513 | || (POINTER_TYPE_P (TREE_TYPE (*expr_p)) | |
1514 | && is_gimple_min_invariant (cached_lhs))) | |
1515 | retval = true; | |
f6be5aa5 | 1516 | |
1517 | if (modify_expr_p | |
1518 | && !tree_ssa_useless_type_conversion_1 (TREE_TYPE (*expr_p), | |
1519 | TREE_TYPE (cached_lhs))) | |
1520 | cached_lhs = fold_convert (TREE_TYPE (*expr_p), cached_lhs); | |
4ee9c684 | 1521 | |
56004dc5 | 1522 | propagate_tree_value (expr_p, cached_lhs); |
22aa74c4 | 1523 | mark_stmt_modified (stmt); |
4ee9c684 | 1524 | } |
1525 | return retval; | |
1526 | } | |
1527 | ||
1528 | /* STMT, a MODIFY_EXPR, may create certain equivalences, in either | |
1529 | the available expressions table or the const_and_copies table. | |
1530 | Detect and record those equivalences. */ | |
1531 | ||
1532 | static void | |
1533 | record_equivalences_from_stmt (tree stmt, | |
4ee9c684 | 1534 | int may_optimize_p, |
1535 | stmt_ann_t ann) | |
1536 | { | |
1537 | tree lhs = TREE_OPERAND (stmt, 0); | |
1538 | enum tree_code lhs_code = TREE_CODE (lhs); | |
4ee9c684 | 1539 | |
1540 | if (lhs_code == SSA_NAME) | |
1541 | { | |
1542 | tree rhs = TREE_OPERAND (stmt, 1); | |
1543 | ||
1544 | /* Strip away any useless type conversions. */ | |
1545 | STRIP_USELESS_TYPE_CONVERSION (rhs); | |
1546 | ||
1547 | /* If the RHS of the assignment is a constant or another variable that | |
1548 | may be propagated, register it in the CONST_AND_COPIES table. We | |
1549 | do not need to record unwind data for this, since this is a true | |
365db11e | 1550 | assignment and not an equivalence inferred from a comparison. All |
4ee9c684 | 1551 | uses of this ssa name are dominated by this assignment, so unwinding |
1552 | just costs time and space. */ | |
1553 | if (may_optimize_p | |
1554 | && (TREE_CODE (rhs) == SSA_NAME | |
1555 | || is_gimple_min_invariant (rhs))) | |
4c7a0518 | 1556 | SSA_NAME_VALUE (lhs) = rhs; |
4ee9c684 | 1557 | } |
1558 | ||
4ee9c684 | 1559 | /* A memory store, even an aliased store, creates a useful |
1560 | equivalence. By exchanging the LHS and RHS, creating suitable | |
1561 | vops and recording the result in the available expression table, | |
1562 | we may be able to expose more redundant loads. */ | |
1563 | if (!ann->has_volatile_ops | |
1564 | && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME | |
1565 | || is_gimple_min_invariant (TREE_OPERAND (stmt, 1))) | |
1566 | && !is_gimple_reg (lhs)) | |
1567 | { | |
1568 | tree rhs = TREE_OPERAND (stmt, 1); | |
1569 | tree new; | |
4ee9c684 | 1570 | |
1571 | /* FIXME: If the LHS of the assignment is a bitfield and the RHS | |
1572 | is a constant, we need to adjust the constant to fit into the | |
1573 | type of the LHS. If the LHS is a bitfield and the RHS is not | |
1574 | a constant, then we can not record any equivalences for this | |
1575 | statement since we would need to represent the widening or | |
1576 | narrowing of RHS. This fixes gcc.c-torture/execute/921016-1.c | |
1577 | and should not be necessary if GCC represented bitfields | |
1578 | properly. */ | |
1579 | if (lhs_code == COMPONENT_REF | |
1580 | && DECL_BIT_FIELD (TREE_OPERAND (lhs, 1))) | |
1581 | { | |
1582 | if (TREE_CONSTANT (rhs)) | |
1583 | rhs = widen_bitfield (rhs, TREE_OPERAND (lhs, 1), lhs); | |
1584 | else | |
1585 | rhs = NULL; | |
1586 | ||
1587 | /* If the value overflowed, then we can not use this equivalence. */ | |
1588 | if (rhs && ! is_gimple_min_invariant (rhs)) | |
1589 | rhs = NULL; | |
1590 | } | |
1591 | ||
1592 | if (rhs) | |
1593 | { | |
4ee9c684 | 1594 | /* Build a new statement with the RHS and LHS exchanged. */ |
40b19772 | 1595 | new = build2 (MODIFY_EXPR, TREE_TYPE (stmt), rhs, lhs); |
4ee9c684 | 1596 | |
b66731e8 | 1597 | create_ssa_artficial_load_stmt (new, stmt); |
4ee9c684 | 1598 | |
1599 | /* Finally enter the statement into the available expression | |
1600 | table. */ | |
9c629f0e | 1601 | lookup_avail_expr (new, true); |
4ee9c684 | 1602 | } |
1603 | } | |
1604 | } | |
1605 | ||
591c2a30 | 1606 | /* Replace *OP_P in STMT with any known equivalent value for *OP_P from |
1607 | CONST_AND_COPIES. */ | |
1608 | ||
1609 | static bool | |
fa0f49c6 | 1610 | cprop_operand (tree stmt, use_operand_p op_p) |
591c2a30 | 1611 | { |
1612 | bool may_have_exposed_new_symbols = false; | |
1613 | tree val; | |
1614 | tree op = USE_FROM_PTR (op_p); | |
1615 | ||
1616 | /* If the operand has a known constant value or it is known to be a | |
1617 | copy of some other variable, use the value or copy stored in | |
1618 | CONST_AND_COPIES. */ | |
4c7a0518 | 1619 | val = SSA_NAME_VALUE (op); |
88dbf20f | 1620 | if (val && val != op && TREE_CODE (val) != VALUE_HANDLE) |
591c2a30 | 1621 | { |
1622 | tree op_type, val_type; | |
1623 | ||
1624 | /* Do not change the base variable in the virtual operand | |
1625 | tables. That would make it impossible to reconstruct | |
1626 | the renamed virtual operand if we later modify this | |
1627 | statement. Also only allow the new value to be an SSA_NAME | |
1628 | for propagation into virtual operands. */ | |
1629 | if (!is_gimple_reg (op) | |
88dbf20f | 1630 | && (TREE_CODE (val) != SSA_NAME |
1631 | || is_gimple_reg (val) | |
1632 | || get_virtual_var (val) != get_virtual_var (op))) | |
591c2a30 | 1633 | return false; |
1634 | ||
93b4f514 | 1635 | /* Do not replace hard register operands in asm statements. */ |
1636 | if (TREE_CODE (stmt) == ASM_EXPR | |
1637 | && !may_propagate_copy_into_asm (op)) | |
1638 | return false; | |
1639 | ||
591c2a30 | 1640 | /* Get the toplevel type of each operand. */ |
1641 | op_type = TREE_TYPE (op); | |
1642 | val_type = TREE_TYPE (val); | |
1643 | ||
1644 | /* While both types are pointers, get the type of the object | |
1645 | pointed to. */ | |
1646 | while (POINTER_TYPE_P (op_type) && POINTER_TYPE_P (val_type)) | |
1647 | { | |
1648 | op_type = TREE_TYPE (op_type); | |
1649 | val_type = TREE_TYPE (val_type); | |
1650 | } | |
1651 | ||
4f7f73c8 | 1652 | /* Make sure underlying types match before propagating a constant by |
1653 | converting the constant to the proper type. Note that convert may | |
1654 | return a non-gimple expression, in which case we ignore this | |
1655 | propagation opportunity. */ | |
1656 | if (TREE_CODE (val) != SSA_NAME) | |
591c2a30 | 1657 | { |
4f7f73c8 | 1658 | if (!lang_hooks.types_compatible_p (op_type, val_type)) |
1659 | { | |
1660 | val = fold_convert (TREE_TYPE (op), val); | |
1661 | if (!is_gimple_min_invariant (val)) | |
1662 | return false; | |
1663 | } | |
591c2a30 | 1664 | } |
1665 | ||
1666 | /* Certain operands are not allowed to be copy propagated due | |
1667 | to their interaction with exception handling and some GCC | |
1668 | extensions. */ | |
4f7f73c8 | 1669 | else if (!may_propagate_copy (op, val)) |
591c2a30 | 1670 | return false; |
652a5bec | 1671 | |
1672 | /* Do not propagate copies if the propagated value is at a deeper loop | |
1673 | depth than the propagatee. Otherwise, this may move loop variant | |
1674 | variables outside of their loops and prevent coalescing | |
1675 | opportunities. If the value was loop invariant, it will be hoisted | |
1676 | by LICM and exposed for copy propagation. */ | |
1677 | if (loop_depth_of_name (val) > loop_depth_of_name (op)) | |
1678 | return false; | |
591c2a30 | 1679 | |
1680 | /* Dump details. */ | |
1681 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1682 | { | |
1683 | fprintf (dump_file, " Replaced '"); | |
1684 | print_generic_expr (dump_file, op, dump_flags); | |
1685 | fprintf (dump_file, "' with %s '", | |
1686 | (TREE_CODE (val) != SSA_NAME ? "constant" : "variable")); | |
1687 | print_generic_expr (dump_file, val, dump_flags); | |
1688 | fprintf (dump_file, "'\n"); | |
1689 | } | |
1690 | ||
1691 | /* If VAL is an ADDR_EXPR or a constant of pointer type, note | |
1692 | that we may have exposed a new symbol for SSA renaming. */ | |
1693 | if (TREE_CODE (val) == ADDR_EXPR | |
1694 | || (POINTER_TYPE_P (TREE_TYPE (op)) | |
1695 | && is_gimple_min_invariant (val))) | |
1696 | may_have_exposed_new_symbols = true; | |
1697 | ||
88dbf20f | 1698 | if (TREE_CODE (val) != SSA_NAME) |
1699 | opt_stats.num_const_prop++; | |
1700 | else | |
1701 | opt_stats.num_copy_prop++; | |
1702 | ||
591c2a30 | 1703 | propagate_value (op_p, val); |
1704 | ||
1705 | /* And note that we modified this statement. This is now | |
1706 | safe, even if we changed virtual operands since we will | |
1707 | rescan the statement and rewrite its operands again. */ | |
22aa74c4 | 1708 | mark_stmt_modified (stmt); |
591c2a30 | 1709 | } |
1710 | return may_have_exposed_new_symbols; | |
1711 | } | |
1712 | ||
1713 | /* CONST_AND_COPIES is a table which maps an SSA_NAME to the current | |
1714 | known value for that SSA_NAME (or NULL if no value is known). | |
1715 | ||
1716 | Propagate values from CONST_AND_COPIES into the uses, vuses and | |
1717 | v_may_def_ops of STMT. */ | |
1718 | ||
1719 | static bool | |
fa0f49c6 | 1720 | cprop_into_stmt (tree stmt) |
591c2a30 | 1721 | { |
1722 | bool may_have_exposed_new_symbols = false; | |
43daa21e | 1723 | use_operand_p op_p; |
1724 | ssa_op_iter iter; | |
591c2a30 | 1725 | |
43daa21e | 1726 | FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_ALL_USES) |
591c2a30 | 1727 | { |
591c2a30 | 1728 | if (TREE_CODE (USE_FROM_PTR (op_p)) == SSA_NAME) |
fa0f49c6 | 1729 | may_have_exposed_new_symbols |= cprop_operand (stmt, op_p); |
591c2a30 | 1730 | } |
1731 | ||
591c2a30 | 1732 | return may_have_exposed_new_symbols; |
1733 | } | |
1734 | ||
1735 | ||
5206b159 | 1736 | /* Optimize the statement pointed to by iterator SI. |
4ee9c684 | 1737 | |
1738 | We try to perform some simplistic global redundancy elimination and | |
1739 | constant propagation: | |
1740 | ||
1741 | 1- To detect global redundancy, we keep track of expressions that have | |
1742 | been computed in this block and its dominators. If we find that the | |
1743 | same expression is computed more than once, we eliminate repeated | |
1744 | computations by using the target of the first one. | |
1745 | ||
1746 | 2- Constant values and copy assignments. This is used to do very | |
1747 | simplistic constant and copy propagation. When a constant or copy | |
1748 | assignment is found, we map the value on the RHS of the assignment to | |
1749 | the variable in the LHS in the CONST_AND_COPIES table. */ | |
1750 | ||
1751 | static void | |
15ea1735 | 1752 | optimize_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, |
1753 | basic_block bb, block_stmt_iterator si) | |
4ee9c684 | 1754 | { |
1755 | stmt_ann_t ann; | |
4c27dd45 | 1756 | tree stmt, old_stmt; |
4ee9c684 | 1757 | bool may_optimize_p; |
1758 | bool may_have_exposed_new_symbols = false; | |
4ee9c684 | 1759 | |
4c27dd45 | 1760 | old_stmt = stmt = bsi_stmt (si); |
54aceb26 | 1761 | |
1762 | if (TREE_CODE (stmt) == COND_EXPR) | |
1763 | canonicalize_comparison (stmt); | |
1764 | ||
22aa74c4 | 1765 | update_stmt_if_modified (stmt); |
4ee9c684 | 1766 | ann = stmt_ann (stmt); |
4ee9c684 | 1767 | opt_stats.num_stmts++; |
1768 | may_have_exposed_new_symbols = false; | |
1769 | ||
1770 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1771 | { | |
1772 | fprintf (dump_file, "Optimizing statement "); | |
1773 | print_generic_stmt (dump_file, stmt, TDF_SLIM); | |
1774 | } | |
1775 | ||
2cf24776 | 1776 | /* Const/copy propagate into USES, VUSES and the RHS of V_MAY_DEFs. */ |
fa0f49c6 | 1777 | may_have_exposed_new_symbols = cprop_into_stmt (stmt); |
4ee9c684 | 1778 | |
1779 | /* If the statement has been modified with constant replacements, | |
1780 | fold its RHS before checking for redundant computations. */ | |
1781 | if (ann->modified) | |
1782 | { | |
f2fae51f | 1783 | tree rhs; |
1784 | ||
4ee9c684 | 1785 | /* Try to fold the statement making sure that STMT is kept |
1786 | up to date. */ | |
1787 | if (fold_stmt (bsi_stmt_ptr (si))) | |
1788 | { | |
1789 | stmt = bsi_stmt (si); | |
1790 | ann = stmt_ann (stmt); | |
1791 | ||
1792 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1793 | { | |
1794 | fprintf (dump_file, " Folded to: "); | |
1795 | print_generic_stmt (dump_file, stmt, TDF_SLIM); | |
1796 | } | |
1797 | } | |
1798 | ||
f2fae51f | 1799 | rhs = get_rhs (stmt); |
1800 | if (rhs && TREE_CODE (rhs) == ADDR_EXPR) | |
750ad201 | 1801 | recompute_tree_invariant_for_addr_expr (rhs); |
f2fae51f | 1802 | |
4ee9c684 | 1803 | /* Constant/copy propagation above may change the set of |
1804 | virtual operands associated with this statement. Folding | |
1805 | may remove the need for some virtual operands. | |
1806 | ||
1807 | Indicate we will need to rescan and rewrite the statement. */ | |
1808 | may_have_exposed_new_symbols = true; | |
1809 | } | |
1810 | ||
1811 | /* Check for redundant computations. Do this optimization only | |
1812 | for assignments that have no volatile ops and conditionals. */ | |
1813 | may_optimize_p = (!ann->has_volatile_ops | |
1814 | && ((TREE_CODE (stmt) == RETURN_EXPR | |
1815 | && TREE_OPERAND (stmt, 0) | |
1816 | && TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR | |
1817 | && ! (TREE_SIDE_EFFECTS | |
1818 | (TREE_OPERAND (TREE_OPERAND (stmt, 0), 1)))) | |
1819 | || (TREE_CODE (stmt) == MODIFY_EXPR | |
1820 | && ! TREE_SIDE_EFFECTS (TREE_OPERAND (stmt, 1))) | |
1821 | || TREE_CODE (stmt) == COND_EXPR | |
1822 | || TREE_CODE (stmt) == SWITCH_EXPR)); | |
1823 | ||
1824 | if (may_optimize_p) | |
8f628ee8 | 1825 | may_have_exposed_new_symbols |= eliminate_redundant_computations (stmt); |
4ee9c684 | 1826 | |
1827 | /* Record any additional equivalences created by this statement. */ | |
1828 | if (TREE_CODE (stmt) == MODIFY_EXPR) | |
1829 | record_equivalences_from_stmt (stmt, | |
4ee9c684 | 1830 | may_optimize_p, |
1831 | ann); | |
1832 | ||
4ee9c684 | 1833 | /* If STMT is a COND_EXPR and it was modified, then we may know |
1834 | where it goes. If that is the case, then mark the CFG as altered. | |
1835 | ||
1836 | This will cause us to later call remove_unreachable_blocks and | |
1837 | cleanup_tree_cfg when it is safe to do so. It is not safe to | |
1838 | clean things up here since removal of edges and such can trigger | |
1839 | the removal of PHI nodes, which in turn can release SSA_NAMEs to | |
1840 | the manager. | |
1841 | ||
1842 | That's all fine and good, except that once SSA_NAMEs are released | |
1843 | to the manager, we must not call create_ssa_name until all references | |
1844 | to released SSA_NAMEs have been eliminated. | |
1845 | ||
1846 | All references to the deleted SSA_NAMEs can not be eliminated until | |
1847 | we remove unreachable blocks. | |
1848 | ||
1849 | We can not remove unreachable blocks until after we have completed | |
1850 | any queued jump threading. | |
1851 | ||
1852 | We can not complete any queued jump threads until we have taken | |
1853 | appropriate variables out of SSA form. Taking variables out of | |
1854 | SSA form can call create_ssa_name and thus we lose. | |
1855 | ||
1856 | Ultimately I suspect we're going to need to change the interface | |
1857 | into the SSA_NAME manager. */ | |
1858 | ||
1859 | if (ann->modified) | |
1860 | { | |
1861 | tree val = NULL; | |
1862 | ||
1863 | if (TREE_CODE (stmt) == COND_EXPR) | |
1864 | val = COND_EXPR_COND (stmt); | |
1865 | else if (TREE_CODE (stmt) == SWITCH_EXPR) | |
1866 | val = SWITCH_COND (stmt); | |
1867 | ||
35c15734 | 1868 | if (val && TREE_CODE (val) == INTEGER_CST && find_taken_edge (bb, val)) |
4ee9c684 | 1869 | cfg_altered = true; |
35c15734 | 1870 | |
1871 | /* If we simplified a statement in such a way as to be shown that it | |
1872 | cannot trap, update the eh information and the cfg to match. */ | |
4c27dd45 | 1873 | if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) |
35c15734 | 1874 | { |
1875 | bitmap_set_bit (need_eh_cleanup, bb->index); | |
1876 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1877 | fprintf (dump_file, " Flagged to clear EH edges.\n"); | |
1878 | } | |
4ee9c684 | 1879 | } |
35c15734 | 1880 | |
4ee9c684 | 1881 | if (may_have_exposed_new_symbols) |
046bfc77 | 1882 | VEC_safe_push (tree, heap, stmts_to_rescan, bsi_stmt (si)); |
4ee9c684 | 1883 | } |
1884 | ||
4ee9c684 | 1885 | /* Search for an existing instance of STMT in the AVAIL_EXPRS table. If |
1886 | found, return its LHS. Otherwise insert STMT in the table and return | |
1887 | NULL_TREE. | |
1888 | ||
1889 | Also, when an expression is first inserted in the AVAIL_EXPRS table, it | |
5206b159 | 1890 | is also added to the stack pointed to by BLOCK_AVAIL_EXPRS_P, so that they |
4ee9c684 | 1891 | can be removed when we finish processing this block and its children. |
1892 | ||
1893 | NOTE: This function assumes that STMT is a MODIFY_EXPR node that | |
1894 | contains no CALL_EXPR on its RHS and makes no volatile nor | |
1895 | aliased references. */ | |
1896 | ||
1897 | static tree | |
9c629f0e | 1898 | lookup_avail_expr (tree stmt, bool insert) |
4ee9c684 | 1899 | { |
1900 | void **slot; | |
1901 | tree lhs; | |
1902 | tree temp; | |
945865c5 | 1903 | struct expr_hash_elt *element = XNEW (struct expr_hash_elt); |
4ee9c684 | 1904 | |
1905 | lhs = TREE_CODE (stmt) == MODIFY_EXPR ? TREE_OPERAND (stmt, 0) : NULL; | |
1906 | ||
1907 | initialize_hash_element (stmt, lhs, element); | |
1908 | ||
1909 | /* Don't bother remembering constant assignments and copy operations. | |
1910 | Constants and copy operations are handled by the constant/copy propagator | |
1911 | in optimize_stmt. */ | |
1912 | if (TREE_CODE (element->rhs) == SSA_NAME | |
1913 | || is_gimple_min_invariant (element->rhs)) | |
1914 | { | |
1915 | free (element); | |
1916 | return NULL_TREE; | |
1917 | } | |
1918 | ||
4ee9c684 | 1919 | /* Finally try to find the expression in the main expression hash table. */ |
1920 | slot = htab_find_slot_with_hash (avail_exprs, element, element->hash, | |
1921 | (insert ? INSERT : NO_INSERT)); | |
1922 | if (slot == NULL) | |
1923 | { | |
1924 | free (element); | |
1925 | return NULL_TREE; | |
1926 | } | |
1927 | ||
1928 | if (*slot == NULL) | |
1929 | { | |
1930 | *slot = (void *) element; | |
046bfc77 | 1931 | VEC_safe_push (tree, heap, avail_exprs_stack, |
f0458177 | 1932 | stmt ? stmt : element->rhs); |
4ee9c684 | 1933 | return NULL_TREE; |
1934 | } | |
1935 | ||
1936 | /* Extract the LHS of the assignment so that it can be used as the current | |
1937 | definition of another variable. */ | |
1938 | lhs = ((struct expr_hash_elt *)*slot)->lhs; | |
1939 | ||
1940 | /* See if the LHS appears in the CONST_AND_COPIES table. If it does, then | |
1941 | use the value from the const_and_copies table. */ | |
1942 | if (TREE_CODE (lhs) == SSA_NAME) | |
1943 | { | |
4c7a0518 | 1944 | temp = SSA_NAME_VALUE (lhs); |
1945 | if (temp && TREE_CODE (temp) != VALUE_HANDLE) | |
4ee9c684 | 1946 | lhs = temp; |
1947 | } | |
1948 | ||
1949 | free (element); | |
1950 | return lhs; | |
1951 | } | |
1952 | ||
4ee9c684 | 1953 | /* Hashing and equality functions for AVAIL_EXPRS. The table stores |
1954 | MODIFY_EXPR statements. We compute a value number for expressions using | |
1955 | the code of the expression and the SSA numbers of its operands. */ | |
1956 | ||
1957 | static hashval_t | |
1958 | avail_expr_hash (const void *p) | |
1959 | { | |
b66731e8 | 1960 | tree stmt = ((struct expr_hash_elt *)p)->stmt; |
4ee9c684 | 1961 | tree rhs = ((struct expr_hash_elt *)p)->rhs; |
b66731e8 | 1962 | tree vuse; |
1963 | ssa_op_iter iter; | |
4ee9c684 | 1964 | hashval_t val = 0; |
4ee9c684 | 1965 | |
1966 | /* iterative_hash_expr knows how to deal with any expression and | |
1967 | deals with commutative operators as well, so just use it instead | |
1968 | of duplicating such complexities here. */ | |
1969 | val = iterative_hash_expr (rhs, val); | |
1970 | ||
1971 | /* If the hash table entry is not associated with a statement, then we | |
1972 | can just hash the expression and not worry about virtual operands | |
1973 | and such. */ | |
b66731e8 | 1974 | if (!stmt || !stmt_ann (stmt)) |
4ee9c684 | 1975 | return val; |
1976 | ||
1977 | /* Add the SSA version numbers of every vuse operand. This is important | |
1978 | because compound variables like arrays are not renamed in the | |
1979 | operands. Rather, the rename is done on the virtual variable | |
1980 | representing all the elements of the array. */ | |
b66731e8 | 1981 | FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, iter, SSA_OP_VUSE) |
1982 | val = iterative_hash_expr (vuse, val); | |
4ee9c684 | 1983 | |
1984 | return val; | |
1985 | } | |
1986 | ||
23ace16d | 1987 | static hashval_t |
1988 | real_avail_expr_hash (const void *p) | |
1989 | { | |
1990 | return ((const struct expr_hash_elt *)p)->hash; | |
1991 | } | |
4ee9c684 | 1992 | |
1993 | static int | |
1994 | avail_expr_eq (const void *p1, const void *p2) | |
1995 | { | |
b66731e8 | 1996 | tree stmt1 = ((struct expr_hash_elt *)p1)->stmt; |
4ee9c684 | 1997 | tree rhs1 = ((struct expr_hash_elt *)p1)->rhs; |
b66731e8 | 1998 | tree stmt2 = ((struct expr_hash_elt *)p2)->stmt; |
4ee9c684 | 1999 | tree rhs2 = ((struct expr_hash_elt *)p2)->rhs; |
2000 | ||
2001 | /* If they are the same physical expression, return true. */ | |
b66731e8 | 2002 | if (rhs1 == rhs2 && stmt1 == stmt2) |
4ee9c684 | 2003 | return true; |
2004 | ||
2005 | /* If their codes are not equal, then quit now. */ | |
2006 | if (TREE_CODE (rhs1) != TREE_CODE (rhs2)) | |
2007 | return false; | |
2008 | ||
2009 | /* In case of a collision, both RHS have to be identical and have the | |
2010 | same VUSE operands. */ | |
2011 | if ((TREE_TYPE (rhs1) == TREE_TYPE (rhs2) | |
2012 | || lang_hooks.types_compatible_p (TREE_TYPE (rhs1), TREE_TYPE (rhs2))) | |
2013 | && operand_equal_p (rhs1, rhs2, OEP_PURE_SAME)) | |
2014 | { | |
b66731e8 | 2015 | bool ret = compare_ssa_operands_equal (stmt1, stmt2, SSA_OP_VUSE); |
2016 | gcc_assert (!ret || ((struct expr_hash_elt *)p1)->hash | |
8c0963c4 | 2017 | == ((struct expr_hash_elt *)p2)->hash); |
b66731e8 | 2018 | return ret; |
4ee9c684 | 2019 | } |
2020 | ||
2021 | return false; | |
2022 | } |